/src/civetweb/src/civetweb.c

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/* Copyright (c) 2013-2021 the Civetweb developers
 * Copyright (c) 2004-2013 Sergey Lyubka
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#if defined(__GNUC__) || defined(__MINGW32__)
#ifndef GCC_VERSION
#define GCC_VERSION                                                            \
  (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif
#if GCC_VERSION >= 40500
/* gcc diagnostic pragmas available */
#define GCC_DIAGNOSTIC
#endif
#endif

#if defined(GCC_DIAGNOSTIC)
/* Disable unused macros warnings - not all defines are required
 * for all systems and all compilers. */
#pragma GCC diagnostic ignored "-Wunused-macros"
/* A padding warning is just plain useless */
#pragma GCC diagnostic ignored "-Wpadded"
#endif

#if defined(__clang__) /* GCC does not (yet) support this pragma */
/* We must set some flags for the headers we include. These flags
 * are reserved ids according to C99, so we need to disable a
 * warning for that. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wreserved-id-macro"
#endif

#if defined(_WIN32)
#if !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS /* Disable deprecation warning in VS2005 */
#endif
#if !defined(_WIN32_WINNT) /* defined for tdm-gcc so we can use getnameinfo */
#define _WIN32_WINNT 0x0502
#endif
#else
#if !defined(_GNU_SOURCE)
#define _GNU_SOURCE /* for setgroups(), pthread_setname_np() */
#endif
#if defined(__linux__) && !defined(_XOPEN_SOURCE)
#define _XOPEN_SOURCE 600 /* For flockfile() on Linux */
#endif
#if defined(__LSB_VERSION__) || defined(__sun)
#define NEED_TIMEGM
#define NO_THREAD_NAME
#endif
#if !defined(_LARGEFILE_SOURCE)
#define _LARGEFILE_SOURCE /* For fseeko(), ftello() */
#endif
#if !defined(_FILE_OFFSET_BITS)
#define _FILE_OFFSET_BITS 64 /* Use 64-bit file offsets by default */
#endif
#if !defined(__STDC_FORMAT_MACROS)
#define __STDC_FORMAT_MACROS /* <inttypes.h> wants this for C++ */
#endif
#if !defined(__STDC_LIMIT_MACROS)
#define __STDC_LIMIT_MACROS /* C++ wants that for INT64_MAX */
#endif
#if !defined(_DARWIN_UNLIMITED_SELECT)
#define _DARWIN_UNLIMITED_SELECT
#endif
#if defined(__sun)
#define __EXTENSIONS__  /* to expose flockfile and friends in stdio.h */
#define __inline inline /* not recognized on older compiler versions */
#endif
#endif

#if defined(__clang__)
/* Enable reserved-id-macro warning again. */
#pragma GCC diagnostic pop
#endif


#if defined(USE_LUA)
#define USE_TIMERS
#endif

#if defined(_MSC_VER)
/* 'type cast' : conversion from 'int' to 'HANDLE' of greater size */
#pragma warning(disable : 4306)
/* conditional expression is constant: introduced by FD_SET(..) */
#pragma warning(disable : 4127)
/* non-constant aggregate initializer: issued due to missing C99 support */
#pragma warning(disable : 4204)
/* padding added after data member */
#pragma warning(disable : 4820)
/* not defined as a preprocessor macro, replacing with '0' for '#if/#elif' */
#pragma warning(disable : 4668)
/* no function prototype given: converting '()' to '(void)' */
#pragma warning(disable : 4255)
/* function has been selected for automatic inline expansion */
#pragma warning(disable : 4711)
#endif


/* This code uses static_assert to check some conditions.
 * Unfortunately some compilers still do not support it, so we have a
 * replacement function here. */
#if defined(__STDC_VERSION__) && __STDC_VERSION__ > 201100L
#define mg_static_assert _Static_assert
#elif defined(__cplusplus) && __cplusplus >= 201103L
#define mg_static_assert static_assert
#else
char static_assert_replacement[1];
#define mg_static_assert(cond, txt)                                            \
  extern char static_assert_replacement[(cond) ? 1 : -1]
#endif

mg_static_assert(sizeof(int) == 4 || sizeof(int) == 8,
                 "int data type size check");
mg_static_assert(sizeof(void *) == 4 || sizeof(void *) == 8,
                 "pointer data type size check");
mg_static_assert(sizeof(void *) >= sizeof(int), "data type size check");


/* Select queue implementation. Diagnosis features originally only implemented
 * for the "ALTERNATIVE_QUEUE" have been ported to the previous queue
 * implementation (NO_ALTERNATIVE_QUEUE) as well. The new configuration value
 * "CONNECTION_QUEUE_SIZE" is only available for the previous queue
 * implementation, since the queue length is independent from the number of
 * worker threads there, while the new queue is one element per worker thread.
 *
 */
#if defined(NO_ALTERNATIVE_QUEUE) && defined(ALTERNATIVE_QUEUE)
/* The queues are exclusive or - only one can be used. */
#error                                                                         \
    "Define ALTERNATIVE_QUEUE or NO_ALTERNATIVE_QUEUE (or none of them), but not both"
#endif
#if !defined(NO_ALTERNATIVE_QUEUE) && !defined(ALTERNATIVE_QUEUE)
/* Use a default implementation */
#define NO_ALTERNATIVE_QUEUE
#endif

#if defined(NO_FILESYSTEMS) && !defined(NO_FILES)
/* File system access:
 * NO_FILES = do not serve any files from the file system automatically.
 * However, with NO_FILES CivetWeb may still write log files, read access
 * control files, default error page files or use API functions like
 * mg_send_file in callbacks to send files from the server local
 * file system.
 * NO_FILES only disables the automatic mapping between URLs and local
 * file names.
 * NO_FILESYSTEM = do not access any file at all. Useful for embedded
 * devices without file system. Logging to files in not available
 * (use callbacks instead) and API functions like mg_send_file are not
 * available.
 * If NO_FILESYSTEM is set, NO_FILES must be set as well.
 */
#error "Inconsistent build flags, NO_FILESYSTEMS requires NO_FILES"
#endif

/* DTL -- including winsock2.h works better if lean and mean */
#if !defined(WIN32_LEAN_AND_MEAN)
#define WIN32_LEAN_AND_MEAN
#endif

#if defined(__SYMBIAN32__)
/* According to https://en.wikipedia.org/wiki/Symbian#History,
 * Symbian is no longer maintained since 2014-01-01.
 * Support for Symbian has been removed from CivetWeb
 */
#error "Symbian is no longer maintained. CivetWeb no longer supports Symbian."
#endif /* __SYMBIAN32__ */

#if defined(__ZEPHYR__)
#include <ctype.h>
#include <fcntl.h>
#include <netdb.h>
#include <poll.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <time.h>

#include <zephyr/kernel.h>

/* Max worker threads is the max of pthreads minus the main application thread
 * and minus the main civetweb thread, thus -2
 */
#define MAX_WORKER_THREADS (CONFIG_MAX_PTHREAD_COUNT - 2)

#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
#define ZEPHYR_STACK_SIZE USE_STACK_SIZE
#else
#define ZEPHYR_STACK_SIZE (1024 * 16)
#endif

K_THREAD_STACK_DEFINE(civetweb_main_stack, ZEPHYR_STACK_SIZE);
K_THREAD_STACK_ARRAY_DEFINE(civetweb_worker_stacks,
                            MAX_WORKER_THREADS,
                            ZEPHYR_STACK_SIZE);

static int zephyr_worker_stack_index;

#endif

#if !defined(CIVETWEB_HEADER_INCLUDED)
/* Include the header file here, so the CivetWeb interface is defined for the
 * entire implementation, including the following forward definitions. */
#include "civetweb.h"
#endif

#if !defined(DEBUG_TRACE)
#if defined(DEBUG)
static void DEBUG_TRACE_FUNC(const char *func,
                             unsigned line,
                             PRINTF_FORMAT_STRING(const char *fmt),
                             ...) PRINTF_ARGS(3, 4);

#define DEBUG_TRACE(fmt, ...)                                                  \
  DEBUG_TRACE_FUNC(__func__, __LINE__, fmt, __VA_ARGS__)

#define NEED_DEBUG_TRACE_FUNC
#if !defined(DEBUG_TRACE_STREAM)
#define DEBUG_TRACE_STREAM stdout
#endif

#else
#define DEBUG_TRACE(fmt, ...)                                                  \
  do {                                                                       \
  } while (0)
#endif /* DEBUG */
#endif /* DEBUG_TRACE */


#if !defined(DEBUG_ASSERT)
#if defined(DEBUG)
#include <stdlib.h>
#define DEBUG_ASSERT(cond)                                                     \
  do {                                                                       \
    if (!(cond)) {                                                         \
      DEBUG_TRACE("ASSERTION FAILED: %s", #cond);                        \
      exit(2); /* Exit with error */                                     \
    }                                                                      \
  } while (0)
#else
#define DEBUG_ASSERT(cond)
#endif /* DEBUG */
#endif


#if defined(__GNUC__) && defined(GCC_INSTRUMENTATION)
void __cyg_profile_func_enter(void *this_fn, void *call_site)
    __attribute__((no_instrument_function));

void __cyg_profile_func_exit(void *this_fn, void *call_site)
    __attribute__((no_instrument_function));

void
__cyg_profile_func_enter(void *this_fn, void *call_site)
{
  if ((void *)this_fn != (void *)printf) {
    printf("E %p %p\n", this_fn, call_site);
  }
}

void
__cyg_profile_func_exit(void *this_fn, void *call_site)
{
  if ((void *)this_fn != (void *)printf) {
    printf("X %p %p\n", this_fn, call_site);
  }
}
#endif


#if !defined(IGNORE_UNUSED_RESULT)
#define IGNORE_UNUSED_RESULT(a) ((void)((a) && 1))
#endif


#if defined(__GNUC__) || defined(__MINGW32__)

/* GCC unused function attribute seems fundamentally broken.
 * Several attempts to tell the compiler "THIS FUNCTION MAY BE USED
 * OR UNUSED" for individual functions failed.
 * Either the compiler creates an "unused-function" warning if a
 * function is not marked with __attribute__((unused)).
 * On the other hand, if the function is marked with this attribute,
 * but is used, the compiler raises a completely idiotic
 * "used-but-marked-unused" warning - and
 *   #pragma GCC diagnostic ignored "-Wused-but-marked-unused"
 * raises error: unknown option after "#pragma GCC diagnostic".
 * Disable this warning completely, until the GCC guys sober up
 * again.
 */

#pragma GCC diagnostic ignored "-Wunused-function"

#define FUNCTION_MAY_BE_UNUSED /* __attribute__((unused)) */

#else
#define FUNCTION_MAY_BE_UNUSED
#endif


/* Some ANSI #includes are not available on Windows CE and Zephyr */
#if !defined(_WIN32_WCE) && !defined(__ZEPHYR__)
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#endif /* !_WIN32_WCE */


#if defined(__clang__)
/* When using -Weverything, clang does not accept it's own headers
 * in a release build configuration. Disable what is too much in
 * -Weverything. */
#pragma clang diagnostic ignored "-Wdisabled-macro-expansion"
#endif

#if defined(__GNUC__) || defined(__MINGW32__)
/* Who on earth came to the conclusion, using __DATE__ should rise
 * an "expansion of date or time macro is not reproducible"
 * warning. That's exactly what was intended by using this macro.
 * Just disable this nonsense warning. */

/* And disabling them does not work either:
 * #pragma clang diagnostic ignored "-Wno-error=date-time"
 * #pragma clang diagnostic ignored "-Wdate-time"
 * So we just have to disable ALL warnings for some lines
 * of code.
 * This seems to be a known GCC bug, not resolved since 2012:
 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431
 */
#endif


#if defined(__MACH__) && defined(__APPLE__) /* Apple OSX section */

#if defined(__clang__)
#if (__clang_major__ == 3) && ((__clang_minor__ == 7) || (__clang_minor__ == 8))
/* Avoid warnings for Xcode 7. It seems it does no longer exist in Xcode 8 */
#pragma clang diagnostic ignored "-Wno-reserved-id-macro"
#pragma clang diagnostic ignored "-Wno-keyword-macro"
#endif
#endif

#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC (1)
#endif
#ifndef CLOCK_REALTIME
#define CLOCK_REALTIME (2)
#endif

#include <mach/clock.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#include <sys/errno.h>
#include <sys/time.h>

/* clock_gettime is not implemented on OSX prior to 10.12 */
static int
_civet_clock_gettime(int clk_id, struct timespec *t)
{
  memset(t, 0, sizeof(*t));
  if (clk_id == CLOCK_REALTIME) {
    struct timeval now;
    int rv = gettimeofday(&now, NULL);
    if (rv) {
      return rv;
    }
    t->tv_sec = now.tv_sec;
    t->tv_nsec = now.tv_usec * 1000;
    return 0;

  } else if (clk_id == CLOCK_MONOTONIC) {
    static uint64_t clock_start_time = 0;
    static mach_timebase_info_data_t timebase_ifo = {0, 0};

    uint64_t now = mach_absolute_time();

    if (clock_start_time == 0) {
      kern_return_t mach_status = mach_timebase_info(&timebase_ifo);
      DEBUG_ASSERT(mach_status == KERN_SUCCESS);

      /* appease "unused variable" warning for release builds */
      (void)mach_status;

      clock_start_time = now;
    }

    now = (uint64_t)((double)(now - clock_start_time)
                     * (double)timebase_ifo.numer
                     / (double)timebase_ifo.denom);

    t->tv_sec = now / 1000000000;
    t->tv_nsec = now % 1000000000;
    return 0;
  }
  return -1; /* EINVAL - Clock ID is unknown */
}

/* if clock_gettime is declared, then __CLOCK_AVAILABILITY will be defined */
#if defined(__CLOCK_AVAILABILITY)
/* If we compiled with Mac OSX 10.12 or later, then clock_gettime will be
 * declared but it may be NULL at runtime. So we need to check before using
 * it. */
static int
_civet_safe_clock_gettime(int clk_id, struct timespec *t)
{
  if (clock_gettime) {
    return clock_gettime(clk_id, t);
  }
  return _civet_clock_gettime(clk_id, t);
}
#define clock_gettime _civet_safe_clock_gettime
#else
#define clock_gettime _civet_clock_gettime
#endif

#endif


#if defined(_WIN32)
#define ERROR_TRY_AGAIN(err) ((err) == WSAEWOULDBLOCK)
#else
/* Unix might return different error codes indicating to try again.
 * For Linux EAGAIN==EWOULDBLOCK, maybe EAGAIN!=EWOULDBLOCK is history from
 * decades ago, but better check both and let the compiler optimize it. */
#define ERROR_TRY_AGAIN(err)                                                   \
  (((err) == EAGAIN) || ((err) == EWOULDBLOCK) || ((err) == EINTR))
#endif

#if defined(USE_ZLIB)
#include "zconf.h"
#include "zlib.h"
#endif


/********************************************************************/
/* CivetWeb configuration defines */
/********************************************************************/

/* Maximum number of threads that can be configured.
 * The number of threads actually created depends on the "num_threads"
 * configuration parameter, but this is the upper limit. */
#if !defined(MAX_WORKER_THREADS)
#define MAX_WORKER_THREADS (1024 * 64) /* in threads (count) */
#endif

/* Timeout interval for select/poll calls.
 * The timeouts depend on "*_timeout_ms" configuration values, but long
 * timeouts are split into timouts as small as SOCKET_TIMEOUT_QUANTUM.
 * This reduces the time required to stop the server. */
#if !defined(SOCKET_TIMEOUT_QUANTUM)
#define SOCKET_TIMEOUT_QUANTUM (2000) /* in ms */
#endif

/* Do not try to compress files smaller than this limit. */
#if !defined(MG_FILE_COMPRESSION_SIZE_LIMIT)
#define MG_FILE_COMPRESSION_SIZE_LIMIT (1024) /* in bytes */
#endif

#if !defined(PASSWORDS_FILE_NAME)
#define PASSWORDS_FILE_NAME ".htpasswd"
#endif

/* Initial buffer size for all CGI environment variables. In case there is
 * not enough space, another block is allocated. */
#if !defined(CGI_ENVIRONMENT_SIZE)
#define CGI_ENVIRONMENT_SIZE (4096) /* in bytes */
#endif

/* Maximum number of environment variables. */
#if !defined(MAX_CGI_ENVIR_VARS)
#define MAX_CGI_ENVIR_VARS (256) /* in variables (count) */
#endif

/* General purpose buffer size. */
#if !defined(MG_BUF_LEN) /* in bytes */
#define MG_BUF_LEN (1024 * 8)
#endif


/********************************************************************/

/* Helper macros */
#if !defined(ARRAY_SIZE)
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
#endif

#include <stdint.h>

/* Standard defines */
#if !defined(INT64_MAX)
#define INT64_MAX (9223372036854775807)
#endif

#define SHUTDOWN_RD (0)
#define SHUTDOWN_WR (1)
#define SHUTDOWN_BOTH (2)

mg_static_assert(MAX_WORKER_THREADS >= 1,
                 "worker threads must be a positive number");

mg_static_assert(sizeof(size_t) == 4 || sizeof(size_t) == 8,
                 "size_t data type size check");


#if defined(_WIN32) /* WINDOWS include block */
#include <malloc.h> /* *alloc( */
#include <stdlib.h> /* *alloc( */
#include <time.h>   /* struct timespec */
#include <windows.h>
#include <winsock2.h> /* DTL add for SO_EXCLUSIVE */
#include <ws2tcpip.h>

typedef const char *SOCK_OPT_TYPE;

/* For a detailed description of these *_PATH_MAX defines, see
 * https://github.com/civetweb/civetweb/issues/937. */

/* UTF8_PATH_MAX is a char buffer size for 259 BMP characters in UTF-8 plus
 * null termination, rounded up to the next 4 bytes boundary */
#define UTF8_PATH_MAX (3 * 260)
/* UTF16_PATH_MAX is the 16-bit wchar_t buffer size required for 259 BMP
 * characters plus termination. (Note: wchar_t is 16 bit on Windows) */
#define UTF16_PATH_MAX (260)

#if !defined(_IN_PORT_T)
#if !defined(in_port_t)
#define in_port_t u_short
#endif
#endif

#if defined(_WIN32_WCE)
#error "WinCE support has ended"
#endif

#include <direct.h>
#include <io.h>
#include <process.h>


#define MAKEUQUAD(lo, hi)                                                      \
  ((uint64_t)(((uint32_t)(lo)) | ((uint64_t)((uint32_t)(hi))) << 32))
#define RATE_DIFF (10000000) /* 100 nsecs */
#define EPOCH_DIFF (MAKEUQUAD(0xd53e8000, 0x019db1de))
#define SYS2UNIX_TIME(lo, hi)                                                  \
  ((time_t)((MAKEUQUAD((lo), (hi)) - EPOCH_DIFF) / RATE_DIFF))

/* Visual Studio 6 does not know __func__ or __FUNCTION__
 * The rest of MS compilers use __FUNCTION__, not C99 __func__
 * Also use _strtoui64 on modern M$ compilers */
#if defined(_MSC_VER)
#if (_MSC_VER < 1300)
#define STRX(x) #x
#define STR(x) STRX(x)
#define __func__ __FILE__ ":" STR(__LINE__)
#define strtoull(x, y, z) ((unsigned __int64)_atoi64(x))
#define strtoll(x, y, z) (_atoi64(x))
#else
#define __func__ __FUNCTION__
#define strtoull(x, y, z) (_strtoui64(x, y, z))
#define strtoll(x, y, z) (_strtoi64(x, y, z))
#endif
#endif /* _MSC_VER */


#define ERRNO ((int)(GetLastError()))
#define NO_SOCKLEN_T


#if defined(_WIN64) || defined(__MINGW64__)
#if !defined(SSL_LIB)

#if defined(OPENSSL_API_3_0)
#define SSL_LIB "libssl-3-x64.dll"
#define CRYPTO_LIB "libcrypto-3-x64.dll"
#endif

#if defined(OPENSSL_API_1_1)
#define SSL_LIB "libssl-1_1-x64.dll"
#define CRYPTO_LIB "libcrypto-1_1-x64.dll"
#endif /* OPENSSL_API_1_1 */

#if defined(OPENSSL_API_1_0)
#define SSL_LIB "ssleay64.dll"
#define CRYPTO_LIB "libeay64.dll"
#endif /* OPENSSL_API_1_0 */

#endif
#else /* defined(_WIN64) || defined(__MINGW64__) */
#if !defined(SSL_LIB)

#if defined(OPENSSL_API_3_0)
#define SSL_LIB "libssl-3.dll"
#define CRYPTO_LIB "libcrypto-3.dll"
#endif

#if defined(OPENSSL_API_1_1)
#define SSL_LIB "libssl-1_1.dll"
#define CRYPTO_LIB "libcrypto-1_1.dll"
#endif /* OPENSSL_API_1_1 */

#if defined(OPENSSL_API_1_0)
#define SSL_LIB "ssleay32.dll"
#define CRYPTO_LIB "libeay32.dll"
#endif /* OPENSSL_API_1_0 */

#endif /* SSL_LIB */
#endif /* defined(_WIN64) || defined(__MINGW64__) */


#define O_NONBLOCK (0)
#if !defined(W_OK)
#define W_OK (2) /* http://msdn.microsoft.com/en-us/library/1w06ktdy.aspx */
#endif
#define _POSIX_
#define INT64_FMT "I64d"
#define UINT64_FMT "I64u"

#define WINCDECL __cdecl
#define vsnprintf_impl _vsnprintf
#define access _access
#define mg_sleep(x) (Sleep(x))

#define pipe(x) _pipe(x, MG_BUF_LEN, _O_BINARY)
#if !defined(popen)
#define popen(x, y) (_popen(x, y))
#endif
#if !defined(pclose)
#define pclose(x) (_pclose(x))
#endif
#define close(x) (_close(x))
#define dlsym(x, y) (GetProcAddress((HINSTANCE)(x), (y)))
#define RTLD_LAZY (0)
#define fseeko(x, y, z) ((_lseeki64(_fileno(x), (y), (z)) == -1) ? -1 : 0)
#define fdopen(x, y) (_fdopen((x), (y)))
#define write(x, y, z) (_write((x), (y), (unsigned)z))
#define read(x, y, z) (_read((x), (y), (unsigned)z))
#define flockfile(x) ((void)pthread_mutex_lock(&global_log_file_lock))
#define funlockfile(x) ((void)pthread_mutex_unlock(&global_log_file_lock))
#define sleep(x) (Sleep((x)*1000))
#define rmdir(x) (_rmdir(x))
#if defined(_WIN64) || !defined(__MINGW32__)
/* Only MinGW 32 bit is missing this function */
#define timegm(x) (_mkgmtime(x))
#else
time_t timegm(struct tm *tm);
#define NEED_TIMEGM
#endif


#if !defined(fileno)
#define fileno(x) (_fileno(x))
#endif /* !fileno MINGW #defines fileno */

typedef struct {
  CRITICAL_SECTION sec; /* Immovable */
} pthread_mutex_t;
typedef DWORD pthread_key_t;
typedef HANDLE pthread_t;
typedef struct {
  pthread_mutex_t threadIdSec;
  struct mg_workerTLS *waiting_thread; /* The chain of threads */
} pthread_cond_t;

#if !defined(__clockid_t_defined)
typedef DWORD clockid_t;
#endif
#if !defined(CLOCK_MONOTONIC)
#define CLOCK_MONOTONIC (1)
#endif
#if !defined(CLOCK_REALTIME)
#define CLOCK_REALTIME (2)
#endif
#if !defined(CLOCK_THREAD)
#define CLOCK_THREAD (3)
#endif
#if !defined(CLOCK_PROCESS)
#define CLOCK_PROCESS (4)
#endif


#if defined(_MSC_VER) && (_MSC_VER >= 1900)
#define _TIMESPEC_DEFINED
#endif
#if !defined(_TIMESPEC_DEFINED)
struct timespec {
  time_t tv_sec; /* seconds */
  long tv_nsec;  /* nanoseconds */
};
#endif

#if !defined(WIN_PTHREADS_TIME_H)
#define MUST_IMPLEMENT_CLOCK_GETTIME
#endif

#if defined(MUST_IMPLEMENT_CLOCK_GETTIME)
#define clock_gettime mg_clock_gettime
static int
clock_gettime(clockid_t clk_id, struct timespec *tp)
{
  FILETIME ft;
  ULARGE_INTEGER li, li2;
  BOOL ok = FALSE;
  double d;
  static double perfcnt_per_sec = 0.0;
  static BOOL initialized = FALSE;

  if (!initialized) {
    QueryPerformanceFrequency((LARGE_INTEGER *)&li);
    perfcnt_per_sec = 1.0 / li.QuadPart;
    initialized = TRUE;
  }

  if (tp) {
    memset(tp, 0, sizeof(*tp));

    if (clk_id == CLOCK_REALTIME) {

      /* BEGIN: CLOCK_REALTIME = wall clock (date and time) */
      GetSystemTimeAsFileTime(&ft);
      li.LowPart = ft.dwLowDateTime;
      li.HighPart = ft.dwHighDateTime;
      li.QuadPart -= 116444736000000000; /* 1.1.1970 in filedate */
      tp->tv_sec = (time_t)(li.QuadPart / 10000000);
      tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
      ok = TRUE;
      /* END: CLOCK_REALTIME */

    } else if (clk_id == CLOCK_MONOTONIC) {

      /* BEGIN: CLOCK_MONOTONIC = stopwatch (time differences) */
      QueryPerformanceCounter((LARGE_INTEGER *)&li);
      d = li.QuadPart * perfcnt_per_sec;
      tp->tv_sec = (time_t)d;
      d -= (double)tp->tv_sec;
      tp->tv_nsec = (long)(d * 1.0E9);
      ok = TRUE;
      /* END: CLOCK_MONOTONIC */

    } else if (clk_id == CLOCK_THREAD) {

      /* BEGIN: CLOCK_THREAD = CPU usage of thread */
      FILETIME t_create, t_exit, t_kernel, t_user;
      if (GetThreadTimes(GetCurrentThread(),
                         &t_create,
                         &t_exit,
                         &t_kernel,
                         &t_user)) {
        li.LowPart = t_user.dwLowDateTime;
        li.HighPart = t_user.dwHighDateTime;
        li2.LowPart = t_kernel.dwLowDateTime;
        li2.HighPart = t_kernel.dwHighDateTime;
        li.QuadPart += li2.QuadPart;
        tp->tv_sec = (time_t)(li.QuadPart / 10000000);
        tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
        ok = TRUE;
      }
      /* END: CLOCK_THREAD */

    } else if (clk_id == CLOCK_PROCESS) {

      /* BEGIN: CLOCK_PROCESS = CPU usage of process */
      FILETIME t_create, t_exit, t_kernel, t_user;
      if (GetProcessTimes(GetCurrentProcess(),
                          &t_create,
                          &t_exit,
                          &t_kernel,
                          &t_user)) {
        li.LowPart = t_user.dwLowDateTime;
        li.HighPart = t_user.dwHighDateTime;
        li2.LowPart = t_kernel.dwLowDateTime;
        li2.HighPart = t_kernel.dwHighDateTime;
        li.QuadPart += li2.QuadPart;
        tp->tv_sec = (time_t)(li.QuadPart / 10000000);
        tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
        ok = TRUE;
      }
      /* END: CLOCK_PROCESS */

    } else {

      /* BEGIN: unknown clock */
      /* ok = FALSE; already set by init */
      /* END: unknown clock */
    }
  }

  return ok ? 0 : -1;
}
#endif


#define pid_t HANDLE /* MINGW typedefs pid_t to int. Using #define here. */

static int pthread_mutex_lock(pthread_mutex_t *);
static int pthread_mutex_unlock(pthread_mutex_t *);
static void path_to_unicode(const struct mg_connection *conn,
                            const char *path,
                            wchar_t *wbuf,
                            size_t wbuf_len);

/* All file operations need to be rewritten to solve #246. */

struct mg_file;

static const char *mg_fgets(char *buf, size_t size, struct mg_file *filep);


/* POSIX dirent interface */
struct dirent {
  char d_name[UTF8_PATH_MAX];
};

typedef struct DIR {
  HANDLE handle;
  WIN32_FIND_DATAW info;
  struct dirent result;
} DIR;

#if defined(HAVE_POLL)
#define mg_pollfd pollfd
#else
struct mg_pollfd {
  SOCKET fd;
  short events;
  short revents;
};
#endif

/* Mark required libraries */
#if defined(_MSC_VER)
#pragma comment(lib, "Ws2_32.lib")
#endif

#else /* defined(_WIN32) - WINDOWS vs UNIX include block */

#include <inttypes.h>

/* Linux & co. internally use UTF8 */
#define UTF8_PATH_MAX (PATH_MAX)

typedef const void *SOCK_OPT_TYPE;

#if defined(ANDROID)
typedef unsigned short int in_port_t;
#endif

#if !defined(__ZEPHYR__)
#include <arpa/inet.h>
#include <ctype.h>
#include <dirent.h>
#include <grp.h>
#include <limits.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <pthread.h>
#include <pwd.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#if defined(USE_X_DOM_SOCKET)
#include <sys/un.h>
#endif
#endif

#define vsnprintf_impl vsnprintf

#if !defined(NO_SSL_DL) && !defined(NO_SSL)
#include <dlfcn.h>
#endif

#if defined(__MACH__) && defined(__APPLE__)
#define SSL_LIB "libssl.dylib"
#define CRYPTO_LIB "libcrypto.dylib"
#else
#if !defined(SSL_LIB)
#define SSL_LIB "libssl.so"
#endif
#if !defined(CRYPTO_LIB)
#define CRYPTO_LIB "libcrypto.so"
#endif
#endif
#if !defined(O_BINARY)
#define O_BINARY (0)
#endif /* O_BINARY */
#define closesocket(a) (close(a))
#define mg_mkdir(conn, path, mode) (mkdir(path, mode))
#define mg_remove(conn, x) (remove(x))
#define mg_sleep(x) (usleep((x)*1000))
#define mg_opendir(conn, x) (opendir(x))
#define mg_closedir(x) (closedir(x))
#define mg_readdir(x) (readdir(x))
#define ERRNO (errno)
#define INVALID_SOCKET (-1)
#define INT64_FMT PRId64
#define UINT64_FMT PRIu64
typedef int SOCKET;
#define WINCDECL

#if defined(__hpux)
/* HPUX 11 does not have monotonic, fall back to realtime */
#if !defined(CLOCK_MONOTONIC)
#define CLOCK_MONOTONIC CLOCK_REALTIME
#endif

/* HPUX defines socklen_t incorrectly as size_t which is 64bit on
 * Itanium.  Without defining _XOPEN_SOURCE or _XOPEN_SOURCE_EXTENDED
 * the prototypes use int* rather than socklen_t* which matches the
 * actual library expectation.  When called with the wrong size arg
 * accept() returns a zero client inet addr and check_acl() always
 * fails.  Since socklen_t is widely used below, just force replace
 * their typedef with int. - DTL
 */
#define socklen_t int
#endif /* hpux */

#define mg_pollfd pollfd

#endif /* defined(_WIN32) - WINDOWS vs UNIX include block */

/* In case our C library is missing "timegm", provide an implementation */
#if defined(NEED_TIMEGM)
static inline int
is_leap(int y)
{
  return (y % 4 == 0 && y % 100 != 0) || y % 400 == 0;
}

static inline int
count_leap(int y)
{
  return (y - 1969) / 4 - (y - 1901) / 100 + (y - 1601) / 400;
}

time_t
timegm(struct tm *tm)
{
  static const unsigned short ydays[] = {
      0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
  int year = tm->tm_year + 1900;
  int mon = tm->tm_mon;
  int mday = tm->tm_mday - 1;
  int hour = tm->tm_hour;
  int min = tm->tm_min;
  int sec = tm->tm_sec;

  if (year < 1970 || mon < 0 || mon > 11 || mday < 0
      || (mday >= ydays[mon + 1] - ydays[mon]
                      + (mon == 1 && is_leap(year) ? 1 : 0))
      || hour < 0 || hour > 23 || min < 0 || min > 59 || sec < 0 || sec > 60)
    return -1;

  time_t res = year - 1970;
  res *= 365;
  res += mday;
  res += ydays[mon] + (mon > 1 && is_leap(year) ? 1 : 0);
  res += count_leap(year);

  res *= 24;
  res += hour;
  res *= 60;
  res += min;
  res *= 60;
  res += sec;
  return res;
}
#endif /* NEED_TIMEGM */


/* va_copy should always be a macro, C99 and C++11 - DTL */
#if !defined(va_copy)
#define va_copy(x, y) ((x) = (y))
#endif


#if defined(_WIN32)
/* Create substitutes for POSIX functions in Win32. */

#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


static pthread_mutex_t global_log_file_lock;

FUNCTION_MAY_BE_UNUSED
static DWORD
pthread_self(void)
{
  return GetCurrentThreadId();
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_key_create(
    pthread_key_t *key,
    void (*_ignored)(void *) /* destructor not supported for Windows */
)
{
  (void)_ignored;

  if ((key != 0)) {
    *key = TlsAlloc();
    return (*key != TLS_OUT_OF_INDEXES) ? 0 : -1;
  }
  return -2;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_key_delete(pthread_key_t key)
{
  return TlsFree(key) ? 0 : 1;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_setspecific(pthread_key_t key, void *value)
{
  return TlsSetValue(key, value) ? 0 : 1;
}


FUNCTION_MAY_BE_UNUSED
static void *
pthread_getspecific(pthread_key_t key)
{
  return TlsGetValue(key);
}

#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif

static struct pthread_mutex_undefined_struct *pthread_mutex_attr = NULL;
#else
static pthread_mutexattr_t pthread_mutex_attr;
#endif /* _WIN32 */


#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
#endif

static pthread_mutex_t global_lock_mutex;


FUNCTION_MAY_BE_UNUSED
static void
mg_global_lock(void)
{
  (void)pthread_mutex_lock(&global_lock_mutex);
}


FUNCTION_MAY_BE_UNUSED
static void
mg_global_unlock(void)
{
  (void)pthread_mutex_unlock(&global_lock_mutex);
}


#if defined(_WIN64)
mg_static_assert(SIZE_MAX == 0xFFFFFFFFFFFFFFFFu, "Mismatch for atomic types");
#elif defined(_WIN32)
mg_static_assert(SIZE_MAX == 0xFFFFFFFFu, "Mismatch for atomic types");
#endif


/* Atomic functions working on ptrdiff_t ("signed size_t").
 * Operations: Increment, Decrement, Add, Maximum.
 * Up to size_t, they do not an atomic "load" operation.
 */
FUNCTION_MAY_BE_UNUSED
static ptrdiff_t
mg_atomic_inc(volatile ptrdiff_t *addr)
{
  ptrdiff_t ret;

#if defined(_WIN64) && !defined(NO_ATOMICS)
  ret = InterlockedIncrement64(addr);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
  ret = InterlockedIncrement(addr);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
  ret = __sync_add_and_fetch(addr, 1);
#else
  mg_global_lock();
  ret = (++(*addr));
  mg_global_unlock();
#endif
  return ret;
}


FUNCTION_MAY_BE_UNUSED
static ptrdiff_t
mg_atomic_dec(volatile ptrdiff_t *addr)
{
  ptrdiff_t ret;

#if defined(_WIN64) && !defined(NO_ATOMICS)
  ret = InterlockedDecrement64(addr);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
  ret = InterlockedDecrement(addr);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
  ret = __sync_sub_and_fetch(addr, 1);
#else
  mg_global_lock();
  ret = (--(*addr));
  mg_global_unlock();
#endif
  return ret;
}


#if defined(USE_SERVER_STATS) || defined(STOP_FLAG_NEEDS_LOCK)
static ptrdiff_t
mg_atomic_add(volatile ptrdiff_t *addr, ptrdiff_t value)
{
  ptrdiff_t ret;

#if defined(_WIN64) && !defined(NO_ATOMICS)
  ret = InterlockedAdd64(addr, value);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
  ret = InterlockedExchangeAdd(addr, value) + value;
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
  ret = __sync_add_and_fetch(addr, value);
#else
  mg_global_lock();
  *addr += value;
  ret = (*addr);
  mg_global_unlock();
#endif
  return ret;
}


FUNCTION_MAY_BE_UNUSED
static ptrdiff_t
mg_atomic_compare_and_swap(volatile ptrdiff_t *addr,
                           ptrdiff_t oldval,
                           ptrdiff_t newval)
{
  ptrdiff_t ret;

#if defined(_WIN64) && !defined(NO_ATOMICS)
  ret = InterlockedCompareExchange64(addr, newval, oldval);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
  ret = InterlockedCompareExchange(addr, newval, oldval);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
  ret = __sync_val_compare_and_swap(addr, oldval, newval);
#else
  mg_global_lock();
  ret = *addr;
  if ((ret != newval) && (ret == oldval)) {
    *addr = newval;
  }
  mg_global_unlock();
#endif
  return ret;
}


static void
mg_atomic_max(volatile ptrdiff_t *addr, ptrdiff_t value)
{
  register ptrdiff_t tmp = *addr;

#if defined(_WIN64) && !defined(NO_ATOMICS)
  while (tmp < value) {
    tmp = InterlockedCompareExchange64(addr, value, tmp);
  }
#elif defined(_WIN32) && !defined(NO_ATOMICS)
  while (tmp < value) {
    tmp = InterlockedCompareExchange(addr, value, tmp);
  }
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
  while (tmp < value) {
    tmp = __sync_val_compare_and_swap(addr, tmp, value);
  }
#else
  mg_global_lock();
  if (*addr < value) {
    *addr = value;
  }
  mg_global_unlock();
#endif
}


static int64_t
mg_atomic_add64(volatile int64_t *addr, int64_t value)
{
  int64_t ret;

#if defined(_WIN64) && !defined(NO_ATOMICS)
  ret = InterlockedAdd64(addr, value);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
  ret = InterlockedExchangeAdd64(addr, value) + value;
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
  ret = __sync_add_and_fetch(addr, value);
#else
  mg_global_lock();
  *addr += value;
  ret = (*addr);
  mg_global_unlock();
#endif
  return ret;
}
#endif


#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic pop
#endif


#if defined(USE_SERVER_STATS)

struct mg_memory_stat {
  volatile ptrdiff_t totalMemUsed;
  volatile ptrdiff_t maxMemUsed;
  volatile ptrdiff_t blockCount;
};


static struct mg_memory_stat *get_memory_stat(struct mg_context *ctx);


static void *
mg_malloc_ex(size_t size,
             struct mg_context *ctx,
             const char *file,
             unsigned line)
{
  void *data = malloc(size + 2 * sizeof(uintptr_t));
  void *memory = 0;
  struct mg_memory_stat *mstat = get_memory_stat(ctx);

#if defined(MEMORY_DEBUGGING)
  char mallocStr[256];
#else
  (void)file;
  (void)line;
#endif

  if (data) {
    ptrdiff_t mmem = mg_atomic_add(&mstat->totalMemUsed, (ptrdiff_t)size);
    mg_atomic_max(&mstat->maxMemUsed, mmem);

    mg_atomic_inc(&mstat->blockCount);
    ((uintptr_t *)data)[0] = size;
    ((uintptr_t *)data)[1] = (uintptr_t)mstat;
    memory = (void *)(((char *)data) + 2 * sizeof(uintptr_t));
  }

#if defined(MEMORY_DEBUGGING)
  sprintf(mallocStr,
          "MEM: %p %5lu alloc   %7lu %4lu --- %s:%u\n",
          memory,
          (unsigned long)size,
          (unsigned long)mstat->totalMemUsed,
          (unsigned long)mstat->blockCount,
          file,
          line);
  DEBUG_TRACE("%s", mallocStr);
#endif

  return memory;
}


static void *
mg_calloc_ex(size_t count,
             size_t size,
             struct mg_context *ctx,
             const char *file,
             unsigned line)
{
  void *data = mg_malloc_ex(size * count, ctx, file, line);

  if (data) {
    memset(data, 0, size * count);
  }
  return data;
}


static void
mg_free_ex(void *memory, const char *file, unsigned line)
{
#if defined(MEMORY_DEBUGGING)
  char mallocStr[256];
#else
  (void)file;
  (void)line;
#endif

  if (memory) {
    void *data = (void *)(((char *)memory) - 2 * sizeof(uintptr_t));
    uintptr_t size = ((uintptr_t *)data)[0];
    struct mg_memory_stat *mstat =
        (struct mg_memory_stat *)(((uintptr_t *)data)[1]);
    mg_atomic_add(&mstat->totalMemUsed, -(ptrdiff_t)size);
    mg_atomic_dec(&mstat->blockCount);

#if defined(MEMORY_DEBUGGING)
    sprintf(mallocStr,
            "MEM: %p %5lu free    %7lu %4lu --- %s:%u\n",
            memory,
            (unsigned long)size,
            (unsigned long)mstat->totalMemUsed,
            (unsigned long)mstat->blockCount,
            file,
            line);
    DEBUG_TRACE("%s", mallocStr);
#endif
    free(data);
  }
}


static void *
mg_realloc_ex(void *memory,
              size_t newsize,
              struct mg_context *ctx,
              const char *file,
              unsigned line)
{
  void *data;
  void *_realloc;
  uintptr_t oldsize;

#if defined(MEMORY_DEBUGGING)
  char mallocStr[256];
#else
  (void)file;
  (void)line;
#endif

  if (newsize) {
    if (memory) {
      /* Reallocate existing block */
      struct mg_memory_stat *mstat;
      data = (void *)(((char *)memory) - 2 * sizeof(uintptr_t));
      oldsize = ((uintptr_t *)data)[0];
      mstat = (struct mg_memory_stat *)((uintptr_t *)data)[1];
      _realloc = realloc(data, newsize + 2 * sizeof(uintptr_t));
      if (_realloc) {
        data = _realloc;
        mg_atomic_add(&mstat->totalMemUsed, -(ptrdiff_t)oldsize);
#if defined(MEMORY_DEBUGGING)
        sprintf(mallocStr,
                "MEM: %p %5lu r-free  %7lu %4lu --- %s:%u\n",
                memory,
                (unsigned long)oldsize,
                (unsigned long)mstat->totalMemUsed,
                (unsigned long)mstat->blockCount,
                file,
                line);
        DEBUG_TRACE("%s", mallocStr);
#endif
        mg_atomic_add(&mstat->totalMemUsed, (ptrdiff_t)newsize);

#if defined(MEMORY_DEBUGGING)
        sprintf(mallocStr,
                "MEM: %p %5lu r-alloc %7lu %4lu --- %s:%u\n",
                memory,
                (unsigned long)newsize,
                (unsigned long)mstat->totalMemUsed,
                (unsigned long)mstat->blockCount,
                file,
                line);
        DEBUG_TRACE("%s", mallocStr);
#endif
        *(uintptr_t *)data = newsize;
        data = (void *)(((char *)data) + 2 * sizeof(uintptr_t));
      } else {
#if defined(MEMORY_DEBUGGING)
        DEBUG_TRACE("%s", "MEM: realloc failed\n");
#endif
        return _realloc;
      }
    } else {
      /* Allocate new block */
      data = mg_malloc_ex(newsize, ctx, file, line);
    }
  } else {
    /* Free existing block */
    data = 0;
    mg_free_ex(memory, file, line);
  }

  return data;
}


#define mg_malloc(a) mg_malloc_ex(a, NULL, __FILE__, __LINE__)
#define mg_calloc(a, b) mg_calloc_ex(a, b, NULL, __FILE__, __LINE__)
#define mg_realloc(a, b) mg_realloc_ex(a, b, NULL, __FILE__, __LINE__)
#define mg_free(a) mg_free_ex(a, __FILE__, __LINE__)

#define mg_malloc_ctx(a, c) mg_malloc_ex(a, c, __FILE__, __LINE__)
#define mg_calloc_ctx(a, b, c) mg_calloc_ex(a, b, c, __FILE__, __LINE__)
#define mg_realloc_ctx(a, b, c) mg_realloc_ex(a, b, c, __FILE__, __LINE__)


#else /* USE_SERVER_STATS */


static __inline void *
mg_malloc(size_t a)
{
  return malloc(a);
}

static __inline void *
mg_calloc(size_t a, size_t b)
{
  return calloc(a, b);
}

static __inline void *
mg_realloc(void *a, size_t b)
{
  return realloc(a, b);
}

static __inline void
mg_free(void *a)
{
  free(a);
}

#define mg_malloc_ctx(a, c) mg_malloc(a)
#define mg_calloc_ctx(a, b, c) mg_calloc(a, b)
#define mg_realloc_ctx(a, b, c) mg_realloc(a, b)
#define mg_free_ctx(a, c) mg_free(a)

#endif /* USE_SERVER_STATS */


static void mg_vsnprintf(const struct mg_connection *conn,
                         int *truncated,
                         char *buf,
                         size_t buflen,
                         const char *fmt,
                         va_list ap);

static void mg_snprintf(const struct mg_connection *conn,
                        int *truncated,
                        char *buf,
                        size_t buflen,
                        PRINTF_FORMAT_STRING(const char *fmt),
                        ...) PRINTF_ARGS(5, 6);

/* This following lines are just meant as a reminder to use the mg-functions
 * for memory management */
#if defined(malloc)
#undef malloc
#endif
#if defined(calloc)
#undef calloc
#endif
#if defined(realloc)
#undef realloc
#endif
#if defined(free)
#undef free
#endif
#if defined(snprintf)
#undef snprintf
#endif
#if defined(vsnprintf)
#undef vsnprintf
#endif
#define malloc DO_NOT_USE_THIS_FUNCTION__USE_mg_malloc
#define calloc DO_NOT_USE_THIS_FUNCTION__USE_mg_calloc
#define realloc DO_NOT_USE_THIS_FUNCTION__USE_mg_realloc
#define free DO_NOT_USE_THIS_FUNCTION__USE_mg_free
#define snprintf DO_NOT_USE_THIS_FUNCTION__USE_mg_snprintf
#if defined(_WIN32)
/* vsnprintf must not be used in any system,
 * but this define only works well for Windows. */
#define vsnprintf DO_NOT_USE_THIS_FUNCTION__USE_mg_vsnprintf
#endif


/* mg_init_library counter */
static int mg_init_library_called = 0;

#if !defined(NO_SSL)
#if defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)                       \
    || defined(OPENSSL_API_3_0)
static int mg_openssl_initialized = 0;
#endif
#if !defined(OPENSSL_API_1_0) && !defined(OPENSSL_API_1_1)                     \
    && !defined(OPENSSL_API_3_0) && !defined(USE_MBEDTLS)
#error "Please define OPENSSL_API_#_# or USE_MBEDTLS"
#endif
#if defined(OPENSSL_API_1_0) && defined(OPENSSL_API_1_1)
#error "Multiple OPENSSL_API versions defined"
#endif
#if defined(OPENSSL_API_1_1) && defined(OPENSSL_API_3_0)
#error "Multiple OPENSSL_API versions defined"
#endif
#if defined(OPENSSL_API_1_0) && defined(OPENSSL_API_3_0)
#error "Multiple OPENSSL_API versions defined"
#endif
#if (defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)                      \
     || defined(OPENSSL_API_3_0))                                              \
    && defined(USE_MBEDTLS)
#error "Multiple SSL libraries defined"
#endif
#endif


static pthread_key_t sTlsKey; /* Thread local storage index */
static volatile ptrdiff_t thread_idx_max = 0;

#if defined(MG_LEGACY_INTERFACE)
#define MG_ALLOW_USING_GET_REQUEST_INFO_FOR_RESPONSE
#endif

struct mg_workerTLS {
  int is_master;
  unsigned long thread_idx;
  void *user_ptr;
#if defined(_WIN32)
  HANDLE pthread_cond_helper_mutex;
  struct mg_workerTLS *next_waiting_thread;
#endif
  const char *alpn_proto;
#if defined(MG_ALLOW_USING_GET_REQUEST_INFO_FOR_RESPONSE)
  char txtbuf[4];
#endif
};


#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
#endif


/* Get a unique thread ID as unsigned long, independent from the data type
 * of thread IDs defined by the operating system API.
 * If two calls to mg_current_thread_id  return the same value, they calls
 * are done from the same thread. If they return different values, they are
 * done from different threads. (Provided this function is used in the same
 * process context and threads are not repeatedly created and deleted, but
 * CivetWeb does not do that).
 * This function must match the signature required for SSL id callbacks:
 * CRYPTO_set_id_callback
 */
FUNCTION_MAY_BE_UNUSED
static unsigned long
mg_current_thread_id(void)
{
#if defined(_WIN32)
  return GetCurrentThreadId();
#else

#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
  /* For every compiler, either "sizeof(pthread_t) > sizeof(unsigned long)"
   * or not, so one of the two conditions will be unreachable by construction.
   * Unfortunately the C standard does not define a way to check this at
   * compile time, since the #if preprocessor conditions can not use the
   * sizeof operator as an argument. */
#endif

  if (sizeof(pthread_t) > sizeof(unsigned long)) {
    /* This is the problematic case for CRYPTO_set_id_callback:
     * The OS pthread_t can not be cast to unsigned long. */
    struct mg_workerTLS *tls =
        (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
    if (tls == NULL) {
      /* SSL called from an unknown thread: Create some thread index.
       */
      tls = (struct mg_workerTLS *)mg_malloc(sizeof(struct mg_workerTLS));
      tls->is_master = -2; /* -2 means "3rd party thread" */
      tls->thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
      pthread_setspecific(sTlsKey, tls);
    }
    return tls->thread_idx;
  } else {
    /* pthread_t may be any data type, so a simple cast to unsigned long
     * can rise a warning/error, depending on the platform.
     * Here memcpy is used as an anything-to-anything cast. */
    unsigned long ret = 0;
    pthread_t t = pthread_self();
    memcpy(&ret, &t, sizeof(pthread_t));
    return ret;
  }

#if defined(__clang__)
#pragma clang diagnostic pop
#endif

#endif
}


FUNCTION_MAY_BE_UNUSED
static uint64_t
mg_get_current_time_ns(void)
{
  struct timespec tsnow;
  clock_gettime(CLOCK_REALTIME, &tsnow);
  return (((uint64_t)tsnow.tv_sec) * 1000000000) + (uint64_t)tsnow.tv_nsec;
}


#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic pop
#endif


#if defined(NEED_DEBUG_TRACE_FUNC)
static void
DEBUG_TRACE_FUNC(const char *func, unsigned line, const char *fmt, ...)
{
  va_list args;
  struct timespec tsnow;

  /* Get some operating system independent thread id */
  unsigned long thread_id = mg_current_thread_id();

  clock_gettime(CLOCK_REALTIME, &tsnow);

  flockfile(DEBUG_TRACE_STREAM);
  fprintf(DEBUG_TRACE_STREAM,
          "*** %lu.%09lu %lu %s:%u: ",
          (unsigned long)tsnow.tv_sec,
          (unsigned long)tsnow.tv_nsec,
          thread_id,
          func,
          line);
  va_start(args, fmt);
  vfprintf(DEBUG_TRACE_STREAM, fmt, args);
  va_end(args);
  putc('\n', DEBUG_TRACE_STREAM);
  fflush(DEBUG_TRACE_STREAM);
  funlockfile(DEBUG_TRACE_STREAM);
}
#endif /* NEED_DEBUG_TRACE_FUNC */


#define MD5_STATIC static
#include "md5.inl"

/* Darwin prior to 7.0 and Win32 do not have socklen_t */
#if defined(NO_SOCKLEN_T)
typedef int socklen_t;
#endif /* NO_SOCKLEN_T */

#define IP_ADDR_STR_LEN (50) /* IPv6 hex string is 46 chars */

#if !defined(MSG_NOSIGNAL)
#define MSG_NOSIGNAL (0)
#endif


/* SSL: mbedTLS vs. no-ssl vs. OpenSSL */
#if defined(USE_MBEDTLS)
/* mbedTLS */
#include "mod_mbedtls.inl"

#elif defined(NO_SSL)
/* no SSL */
typedef struct SSL SSL; /* dummy for SSL argument to push/pull */
typedef struct SSL_CTX SSL_CTX;

#elif defined(NO_SSL_DL)
/* OpenSSL without dynamic loading */
#include <openssl/bn.h>
#include <openssl/conf.h>
#include <openssl/crypto.h>
#include <openssl/dh.h>
#include <openssl/engine.h>
#include <openssl/err.h>
#include <openssl/opensslv.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/tls1.h>
#include <openssl/x509.h>

#if defined(WOLFSSL_VERSION)
/* Additional defines for WolfSSL, see
 * https://github.com/civetweb/civetweb/issues/583 */
#include "wolfssl_extras.inl"
#endif

#if defined(OPENSSL_IS_BORINGSSL)
/* From boringssl/src/include/openssl/mem.h:
 *
 * OpenSSL has, historically, had a complex set of malloc debugging options.
 * However, that was written in a time before Valgrind and ASAN. Since we now
 * have those tools, the OpenSSL allocation functions are simply macros around
 * the standard memory functions.
 *
 * #define OPENSSL_free free */
#define free free
// disable for boringssl
#define CONF_modules_unload(a) ((void)0)
#define ENGINE_cleanup() ((void)0)
#endif

/* If OpenSSL headers are included, automatically select the API version */
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
#if !defined(OPENSSL_API_3_0)
#define OPENSSL_API_3_0
#endif
#define OPENSSL_REMOVE_THREAD_STATE()
#else
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
#if !defined(OPENSSL_API_1_1)
#define OPENSSL_API_1_1
#endif
#define OPENSSL_REMOVE_THREAD_STATE()
#else
#if !defined(OPENSSL_API_1_0)
#define OPENSSL_API_1_0
#endif
#define OPENSSL_REMOVE_THREAD_STATE() ERR_remove_thread_state(NULL)
#endif
#endif


#else
/* SSL loaded dynamically from DLL / shared object */
/* Add all prototypes here, to be independent from OpenSSL source
 * installation. */
#include "openssl_dl.inl"

#endif /* Various SSL bindings */


#if !defined(NO_CACHING)
static const char month_names[][4] = {"Jan",
                                      "Feb",
                                      "Mar",
                                      "Apr",
                                      "May",
                                      "Jun",
                                      "Jul",
                                      "Aug",
                                      "Sep",
                                      "Oct",
                                      "Nov",
                                      "Dec"};
#endif /* !NO_CACHING */


/* Unified socket address. For IPv6 support, add IPv6 address structure in
 * the union u. */
union usa {
  struct sockaddr sa;
  struct sockaddr_in sin;
#if defined(USE_IPV6)
  struct sockaddr_in6 sin6;
#endif
#if defined(USE_X_DOM_SOCKET)
  struct sockaddr_un sun;
#endif
};

#if defined(USE_X_DOM_SOCKET)
static unsigned short
USA_IN_PORT_UNSAFE(union usa *s)
{
  if (s->sa.sa_family == AF_INET)
    return s->sin.sin_port;
#if defined(USE_IPV6)
  if (s->sa.sa_family == AF_INET6)
    return s->sin6.sin6_port;
#endif
  return 0;
}
#endif
#if defined(USE_IPV6)
#define USA_IN_PORT_UNSAFE(s)                                                  \
  (((s)->sa.sa_family == AF_INET6) ? (s)->sin6.sin6_port : (s)->sin.sin_port)
#else
#define USA_IN_PORT_UNSAFE(s) ((s)->sin.sin_port)
#endif

/* Describes a string (chunk of memory). */
struct vec {
  const char *ptr;
  size_t len;
};

struct mg_file_stat {
  /* File properties filled by mg_stat: */
  uint64_t size;
  time_t last_modified;
  int is_directory; /* Set to 1 if mg_stat is called for a directory */
  int is_gzipped;   /* Set to 1 if the content is gzipped, in which
                     * case we need a "Content-Eencoding: gzip" header */
  int location;     /* 0 = nowhere, 1 = on disk, 2 = in memory */
};


struct mg_file_access {
  /* File properties filled by mg_fopen: */
  FILE *fp;
};

struct mg_file {
  struct mg_file_stat stat;
  struct mg_file_access access;
};


#define STRUCT_FILE_INITIALIZER                                                \
  {                                                                          \
    {(uint64_t)0, (time_t)0, 0, 0, 0},                                     \
    {                                                                      \
      (FILE *)NULL                                                       \
    }                                                                      \
  }


/* Describes listening socket, or socket which was accept()-ed by the master
 * thread and queued for future handling by the worker thread. */
struct socket {
  SOCKET sock;             /* Listening socket */
  union usa lsa;           /* Local socket address */
  union usa rsa;           /* Remote socket address */
  unsigned char is_ssl;    /* Is port SSL-ed */
  unsigned char ssl_redir; /* Is port supposed to redirect everything to SSL
                            * port */
  unsigned char in_use;    /* 0: invalid, 1: valid, 2: free */
};


/* Enum const for all options must be in sync with
 * static struct mg_option config_options[]
 * This is tested in the unit test (test/private.c)
 * "Private Config Options"
 */
enum {
  /* Once for each server */
  LISTENING_PORTS,
  NUM_THREADS,
  RUN_AS_USER,
  CONFIG_TCP_NODELAY, /* Prepended CONFIG_ to avoid conflict with the
                       * socket option typedef TCP_NODELAY. */
  MAX_REQUEST_SIZE,
  LINGER_TIMEOUT,
  CONNECTION_QUEUE_SIZE,
  LISTEN_BACKLOG_SIZE,
#if defined(__linux__)
  ALLOW_SENDFILE_CALL,
#endif
#if defined(_WIN32)
  CASE_SENSITIVE_FILES,
#endif
  THROTTLE,
  ENABLE_KEEP_ALIVE,
  REQUEST_TIMEOUT,
  KEEP_ALIVE_TIMEOUT,
#if defined(USE_WEBSOCKET)
  WEBSOCKET_TIMEOUT,
  ENABLE_WEBSOCKET_PING_PONG,
#endif
  DECODE_URL,
  DECODE_QUERY_STRING,
#if defined(USE_LUA)
  LUA_BACKGROUND_SCRIPT,
  LUA_BACKGROUND_SCRIPT_PARAMS,
#endif
#if defined(USE_HTTP2)
  ENABLE_HTTP2,
#endif

  /* Once for each domain */
  DOCUMENT_ROOT,

  ACCESS_LOG_FILE,
  ERROR_LOG_FILE,

  CGI_EXTENSIONS,
  CGI_ENVIRONMENT,
  CGI_INTERPRETER,
  CGI_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
  CGI_TIMEOUT,
#endif
  CGI_BUFFERING,

  CGI2_EXTENSIONS,
  CGI2_ENVIRONMENT,
  CGI2_INTERPRETER,
  CGI2_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
  CGI2_TIMEOUT,
#endif
  CGI2_BUFFERING,

#if defined(USE_4_CGI)
  CGI3_EXTENSIONS,
  CGI3_ENVIRONMENT,
  CGI3_INTERPRETER,
  CGI3_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
  CGI3_TIMEOUT,
#endif
  CGI3_BUFFERING,

  CGI4_EXTENSIONS,
  CGI4_ENVIRONMENT,
  CGI4_INTERPRETER,
  CGI4_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
  CGI4_TIMEOUT,
#endif
  CGI4_BUFFERING,
#endif

  PUT_DELETE_PASSWORDS_FILE, /* must follow CGI_* */
  PROTECT_URI,
  AUTHENTICATION_DOMAIN,
  ENABLE_AUTH_DOMAIN_CHECK,
  SSI_EXTENSIONS,
  ENABLE_DIRECTORY_LISTING,
  ENABLE_WEBDAV,
  GLOBAL_PASSWORDS_FILE,
  INDEX_FILES,
  ACCESS_CONTROL_LIST,
  EXTRA_MIME_TYPES,
  SSL_CERTIFICATE,
  SSL_CERTIFICATE_CHAIN,
  URL_REWRITE_PATTERN,
  HIDE_FILES,
  SSL_DO_VERIFY_PEER,
  SSL_CACHE_TIMEOUT,
  SSL_CA_PATH,
  SSL_CA_FILE,
  SSL_VERIFY_DEPTH,
  SSL_DEFAULT_VERIFY_PATHS,
  SSL_CIPHER_LIST,
  SSL_PROTOCOL_VERSION,
  SSL_SHORT_TRUST,

#if defined(USE_LUA)
  LUA_PRELOAD_FILE,
  LUA_SCRIPT_EXTENSIONS,
  LUA_SERVER_PAGE_EXTENSIONS,
#if defined(MG_EXPERIMENTAL_INTERFACES)
  LUA_DEBUG_PARAMS,
#endif
#endif
#if defined(USE_DUKTAPE)
  DUKTAPE_SCRIPT_EXTENSIONS,
#endif

#if defined(USE_WEBSOCKET)
  WEBSOCKET_ROOT,
#endif
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  LUA_WEBSOCKET_EXTENSIONS,
#endif

  ACCESS_CONTROL_ALLOW_ORIGIN,
  ACCESS_CONTROL_ALLOW_METHODS,
  ACCESS_CONTROL_ALLOW_HEADERS,
  ERROR_PAGES,
#if !defined(NO_CACHING)
  STATIC_FILE_MAX_AGE,
  STATIC_FILE_CACHE_CONTROL,
#endif
#if !defined(NO_SSL)
  STRICT_HTTPS_MAX_AGE,
#endif
  ADDITIONAL_HEADER,
  ALLOW_INDEX_SCRIPT_SUB_RES,

  NUM_OPTIONS
};


/* Config option name, config types, default value.
 * Must be in the same order as the enum const above.
 */
static const struct mg_option config_options[] = {

    /* Once for each server */
    {"listening_ports", MG_CONFIG_TYPE_STRING_LIST, "8080"},
    {"num_threads", MG_CONFIG_TYPE_NUMBER, "50"},
    {"run_as_user", MG_CONFIG_TYPE_STRING, NULL},
    {"tcp_nodelay", MG_CONFIG_TYPE_NUMBER, "0"},
    {"max_request_size", MG_CONFIG_TYPE_NUMBER, "16384"},
    {"linger_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
    {"connection_queue", MG_CONFIG_TYPE_NUMBER, "20"},
    {"listen_backlog", MG_CONFIG_TYPE_NUMBER, "200"},
#if defined(__linux__)
    {"allow_sendfile_call", MG_CONFIG_TYPE_BOOLEAN, "yes"},
#endif
#if defined(_WIN32)
    {"case_sensitive", MG_CONFIG_TYPE_BOOLEAN, "no"},
#endif
    {"throttle", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"enable_keep_alive", MG_CONFIG_TYPE_BOOLEAN, "no"},
    {"request_timeout_ms", MG_CONFIG_TYPE_NUMBER, "30000"},
    {"keep_alive_timeout_ms", MG_CONFIG_TYPE_NUMBER, "500"},
#if defined(USE_WEBSOCKET)
    {"websocket_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
    {"enable_websocket_ping_pong", MG_CONFIG_TYPE_BOOLEAN, "no"},
#endif
    {"decode_url", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"decode_query_string", MG_CONFIG_TYPE_BOOLEAN, "no"},
#if defined(USE_LUA)
    {"lua_background_script", MG_CONFIG_TYPE_FILE, NULL},
    {"lua_background_script_params", MG_CONFIG_TYPE_STRING_LIST, NULL},
#endif
#if defined(USE_HTTP2)
    {"enable_http2", MG_CONFIG_TYPE_BOOLEAN, "no"},
#endif

    /* Once for each domain */
    {"document_root", MG_CONFIG_TYPE_DIRECTORY, NULL},

    {"access_log_file", MG_CONFIG_TYPE_FILE, NULL},
    {"error_log_file", MG_CONFIG_TYPE_FILE, NULL},

    {"cgi_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.cgi$|**.pl$|**.php$"},
    {"cgi_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},

    {"cgi2_pattern", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
    {"cgi2_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi2_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi2_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi2_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi2_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},

#if defined(USE_4_CGI)
    {"cgi3_pattern", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
    {"cgi3_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi3_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi3_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi3_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi3_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},

    {"cgi4_pattern", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
    {"cgi4_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi4_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi4_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi4_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi4_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},

#endif

    {"put_delete_auth_file", MG_CONFIG_TYPE_FILE, NULL},
    {"protect_uri", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"authentication_domain", MG_CONFIG_TYPE_STRING, "mydomain.com"},
    {"enable_auth_domain_check", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"ssi_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.shtml$|**.shtm$"},
    {"enable_directory_listing", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"enable_webdav", MG_CONFIG_TYPE_BOOLEAN, "no"},
    {"global_auth_file", MG_CONFIG_TYPE_FILE, NULL},
    {"index_files",
     MG_CONFIG_TYPE_STRING_LIST,
#if defined(USE_LUA)
     "index.xhtml,index.html,index.htm,"
     "index.lp,index.lsp,index.lua,index.cgi,"
     "index.shtml,index.php"},
#else
     "index.xhtml,index.html,index.htm,index.cgi,index.shtml,index.php"},
#endif
    {"access_control_list", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"extra_mime_types", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"ssl_certificate", MG_CONFIG_TYPE_FILE, NULL},
    {"ssl_certificate_chain", MG_CONFIG_TYPE_FILE, NULL},
    {"url_rewrite_patterns", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"hide_files_patterns", MG_CONFIG_TYPE_EXT_PATTERN, NULL},

    {"ssl_verify_peer", MG_CONFIG_TYPE_YES_NO_OPTIONAL, "no"},
    {"ssl_cache_timeout", MG_CONFIG_TYPE_NUMBER, "-1"},

    {"ssl_ca_path", MG_CONFIG_TYPE_DIRECTORY, NULL},
    {"ssl_ca_file", MG_CONFIG_TYPE_FILE, NULL},
    {"ssl_verify_depth", MG_CONFIG_TYPE_NUMBER, "9"},
    {"ssl_default_verify_paths", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"ssl_cipher_list", MG_CONFIG_TYPE_STRING, NULL},

    /* HTTP2 requires ALPN, and anyway TLS1.2 should be considered
     * as a minimum in 2020 */
    {"ssl_protocol_version", MG_CONFIG_TYPE_NUMBER, "4"},

    {"ssl_short_trust", MG_CONFIG_TYPE_BOOLEAN, "no"},

#if defined(USE_LUA)
    {"lua_preload_file", MG_CONFIG_TYPE_FILE, NULL},
    {"lua_script_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.lua$"},
    {"lua_server_page_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.lp$|**.lsp$"},
#if defined(MG_EXPERIMENTAL_INTERFACES)
    {"lua_debug", MG_CONFIG_TYPE_STRING, NULL},
#endif
#endif
#if defined(USE_DUKTAPE)
    /* The support for duktape is still in alpha version state.
     * The name of this config option might change. */
    {"duktape_script_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.ssjs$"},
#endif

#if defined(USE_WEBSOCKET)
    {"websocket_root", MG_CONFIG_TYPE_DIRECTORY, NULL},
#endif
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    {"lua_websocket_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.lua$"},
#endif
    {"access_control_allow_origin", MG_CONFIG_TYPE_STRING, "*"},
    {"access_control_allow_methods", MG_CONFIG_TYPE_STRING, "*"},
    {"access_control_allow_headers", MG_CONFIG_TYPE_STRING, "*"},
    {"error_pages", MG_CONFIG_TYPE_DIRECTORY, NULL},
#if !defined(NO_CACHING)
    {"static_file_max_age", MG_CONFIG_TYPE_NUMBER, "3600"},
    {"static_file_cache_control", MG_CONFIG_TYPE_STRING, NULL},
#endif
#if !defined(NO_SSL)
    {"strict_transport_security_max_age", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"additional_header", MG_CONFIG_TYPE_STRING_MULTILINE, NULL},
    {"allow_index_script_resource", MG_CONFIG_TYPE_BOOLEAN, "no"},

    {NULL, MG_CONFIG_TYPE_UNKNOWN, NULL}};


/* Check if the config_options and the corresponding enum have compatible
 * sizes. */
mg_static_assert((sizeof(config_options) / sizeof(config_options[0]))
                     == (NUM_OPTIONS + 1),
                 "config_options and enum not sync");


enum { REQUEST_HANDLER, WEBSOCKET_HANDLER, AUTH_HANDLER };


struct mg_handler_info {
  /* Name/Pattern of the URI. */
  char *uri;
  size_t uri_len;

  /* handler type */
  int handler_type;

  /* Handler for http/https or requests. */
  mg_request_handler handler;
  unsigned int refcount;
  int removing;

  /* Handler for ws/wss (websocket) requests. */
  mg_websocket_connect_handler connect_handler;
  mg_websocket_ready_handler ready_handler;
  mg_websocket_data_handler data_handler;
  mg_websocket_close_handler close_handler;

  /* accepted subprotocols for ws/wss requests. */
  struct mg_websocket_subprotocols *subprotocols;

  /* Handler for authorization requests */
  mg_authorization_handler auth_handler;

  /* User supplied argument for the handler function. */
  void *cbdata;

  /* next handler in a linked list */
  struct mg_handler_info *next;
};


enum {
  CONTEXT_INVALID,
  CONTEXT_SERVER,
  CONTEXT_HTTP_CLIENT,
  CONTEXT_WS_CLIENT
};


struct mg_domain_context {
  SSL_CTX *ssl_ctx;                 /* SSL context */
  char *config[NUM_OPTIONS];        /* Civetweb configuration parameters */
  struct mg_handler_info *handlers; /* linked list of uri handlers */
  int64_t ssl_cert_last_mtime;

  /* Server nonce */
  uint64_t auth_nonce_mask;  /* Mask for all nonce values */
  unsigned long nonce_count; /* Used nonces, used for authentication */

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  /* linked list of shared lua websockets */
  struct mg_shared_lua_websocket_list *shared_lua_websockets;
#endif

  /* Linked list of domains */
  struct mg_domain_context *next;
};


/* Stop flag can be "volatile" or require a lock.
 * MSDN uses volatile for "Interlocked" operations, but also explicitly
 * states a read operation for int is always atomic. */
#if defined(STOP_FLAG_NEEDS_LOCK)

typedef ptrdiff_t volatile stop_flag_t;

static int
STOP_FLAG_IS_ZERO(const stop_flag_t *f)
{
  stop_flag_t sf = mg_atomic_add((stop_flag_t *)f, 0);
  return (sf == 0);
}

static int
STOP_FLAG_IS_TWO(stop_flag_t *f)
{
  stop_flag_t sf = mg_atomic_add(f, 0);
  return (sf == 2);
}

static void
STOP_FLAG_ASSIGN(stop_flag_t *f, stop_flag_t v)
{
  stop_flag_t sf;
  do {
    sf = mg_atomic_compare_and_swap(f, *f, v);
  } while (sf != v);
}

#else /* STOP_FLAG_NEEDS_LOCK */

typedef int volatile stop_flag_t;
#define STOP_FLAG_IS_ZERO(f) ((*(f)) == 0)
#define STOP_FLAG_IS_TWO(f) ((*(f)) == 2)
#define STOP_FLAG_ASSIGN(f, v) ((*(f)) = (v))

#endif /* STOP_FLAG_NEEDS_LOCK */


#if !defined(NUM_WEBDAV_LOCKS)
#define NUM_WEBDAV_LOCKS 10
#endif
#if !defined(LOCK_DURATION_S)
#define LOCK_DURATION_S 60
#endif


struct twebdav_lock {
  uint64_t locktime;
  char token[33];
  char path[UTF8_PATH_MAX * 2];
  char user[UTF8_PATH_MAX * 2];
};


struct mg_context {

  /* Part 1 - Physical context:
   * This holds threads, ports, timeouts, ...
   * set for the entire server, independent from the
   * addressed hostname.
   */

  /* Connection related */
  int context_type; /* See CONTEXT_* above */

  struct socket *listening_sockets;
  struct mg_pollfd *listening_socket_fds;
  unsigned int num_listening_sockets;

  struct mg_connection *worker_connections; /* The connection struct, pre-
                                             * allocated for each worker */

#if defined(USE_SERVER_STATS)
  volatile ptrdiff_t active_connections;
  volatile ptrdiff_t max_active_connections;
  volatile ptrdiff_t total_connections;
  volatile ptrdiff_t total_requests;
  volatile int64_t total_data_read;
  volatile int64_t total_data_written;
#endif

  /* Thread related */
  stop_flag_t stop_flag;        /* Should we stop event loop */
  pthread_mutex_t thread_mutex; /* Protects client_socks or queue */

  pthread_t masterthreadid; /* The master thread ID */
  unsigned int
      cfg_worker_threads;      /* The number of configured worker threads. */
  pthread_t *worker_threadids; /* The worker thread IDs */
  unsigned long starter_thread_idx; /* thread index which called mg_start */

  /* Connection to thread dispatching */
#if defined(ALTERNATIVE_QUEUE)
  struct socket *client_socks;
  void **client_wait_events;
#else
  struct socket *squeue; /* Socket queue (sq) : accepted sockets waiting for a
                         worker thread */
  volatile int sq_head;  /* Head of the socket queue */
  volatile int sq_tail;  /* Tail of the socket queue */
  pthread_cond_t sq_full;  /* Signaled when socket is produced */
  pthread_cond_t sq_empty; /* Signaled when socket is consumed */
  volatile int sq_blocked; /* Status information: sq is full */
  int sq_size;             /* No of elements in socket queue */
#if defined(USE_SERVER_STATS)
  int sq_max_fill;
#endif /* USE_SERVER_STATS */
#endif /* ALTERNATIVE_QUEUE */

  /* Memory related */
  unsigned int max_request_size; /* The max request size */

#if defined(USE_SERVER_STATS)
  struct mg_memory_stat ctx_memory;
#endif

  /* WebDAV lock structures */
  struct twebdav_lock webdav_lock[NUM_WEBDAV_LOCKS];

  /* Operating system related */
  char *systemName;  /* What operating system is running */
  time_t start_time; /* Server start time, used for authentication
                      * and for diagnstics. */

#if defined(USE_TIMERS)
  struct ttimers *timers;
#endif

  /* Lua specific: Background operations and shared websockets */
#if defined(USE_LUA)
  void *lua_background_state;   /* lua_State (here as void *) */
  pthread_mutex_t lua_bg_mutex; /* Protect background state */
  int lua_bg_log_available;     /* Use Lua background state for access log */
#endif

  /* Server nonce */
  pthread_mutex_t nonce_mutex; /* Protects ssl_ctx, handlers,
                                * ssl_cert_last_mtime, nonce_count, and
                                * next (linked list) */

  /* Server callbacks */
  struct mg_callbacks callbacks; /* User-defined callback function */
  void *user_data;               /* User-defined data */

  /* Part 2 - Logical domain:
   * This holds hostname, TLS certificate, document root, ...
   * set for a domain hosted at the server.
   * There may be multiple domains hosted at one physical server.
   * The default domain "dd" is the first element of a list of
   * domains.
   */
  struct mg_domain_context dd; /* default domain */
};


#if defined(USE_SERVER_STATS)
static struct mg_memory_stat mg_common_memory = {0, 0, 0};

static struct mg_memory_stat *
get_memory_stat(struct mg_context *ctx)
{
  if (ctx) {
    return &(ctx->ctx_memory);
  }
  return &mg_common_memory;
}
#endif

enum {
  CONNECTION_TYPE_INVALID = 0,
  CONNECTION_TYPE_REQUEST = 1,
  CONNECTION_TYPE_RESPONSE = 2
};

enum {
  PROTOCOL_TYPE_HTTP1 = 0,
  PROTOCOL_TYPE_WEBSOCKET = 1,
  PROTOCOL_TYPE_HTTP2 = 2
};


#if defined(USE_HTTP2)
#if !defined(HTTP2_DYN_TABLE_SIZE)
#define HTTP2_DYN_TABLE_SIZE (256)
#endif

struct mg_http2_connection {
  uint32_t stream_id;
  uint32_t dyn_table_size;
  struct mg_header dyn_table[HTTP2_DYN_TABLE_SIZE];
};
#endif


struct mg_connection {
  int connection_type; /* see CONNECTION_TYPE_* above */
  int protocol_type;   /* see PROTOCOL_TYPE_*: 0=http/1.x, 1=ws, 2=http/2 */
  int request_state;   /* 0: nothing sent, 1: header partially sent, 2: header
                       fully sent */
#if defined(USE_HTTP2)
  struct mg_http2_connection http2;
#endif

  struct mg_request_info request_info;
  struct mg_response_info response_info;

  struct mg_context *phys_ctx;
  struct mg_domain_context *dom_ctx;

#if defined(USE_SERVER_STATS)
  int conn_state; /* 0 = undef, numerical value may change in different
                   * versions. For the current definition, see
                   * mg_get_connection_info_impl */
#endif

  SSL *ssl;               /* SSL descriptor */
  struct socket client;   /* Connected client */
  time_t conn_birth_time; /* Time (wall clock) when connection was
                           * established */
#if defined(USE_SERVER_STATS)
  time_t conn_close_time; /* Time (wall clock) when connection was
                           * closed (or 0 if still open) */
  double processing_time; /* Processing time for one request. */
#endif
  struct timespec req_time; /* Time (since system start) when the request
                             * was received */
  int64_t num_bytes_sent;   /* Total bytes sent to client */
  int64_t content_len;      /* How many bytes of content can be read
                             * !is_chunked: Content-Length header value
                             *              or -1 (until connection closed,
                             *                     not allowed for a request)
                             * is_chunked: >= 0, appended gradually
                             */
  int64_t consumed_content; /* How many bytes of content have been read */
  int is_chunked;           /* Transfer-Encoding is chunked:
                             * 0 = not chunked,
                             * 1 = chunked, not yet, or some data read,
                             * 2 = chunked, has error,
                             * 3 = chunked, all data read except trailer,
                             * 4 = chunked, all data read
                             */
  char *buf;                /* Buffer for received data */
  char *path_info;          /* PATH_INFO part of the URL */

  int must_close;       /* 1 if connection must be closed */
  int accept_gzip;      /* 1 if gzip encoding is accepted */
  int in_error_handler; /* 1 if in handler for user defined error
                         * pages */
#if defined(USE_WEBSOCKET)
  int in_websocket_handling; /* 1 if in read_websocket */
#endif
#if defined(USE_ZLIB) && defined(USE_WEBSOCKET)                                \
    && defined(MG_EXPERIMENTAL_INTERFACES)
  /* Parameters for websocket data compression according to rfc7692 */
  int websocket_deflate_server_max_windows_bits;
  int websocket_deflate_client_max_windows_bits;
  int websocket_deflate_server_no_context_takeover;
  int websocket_deflate_client_no_context_takeover;
  int websocket_deflate_initialized;
  int websocket_deflate_flush;
  z_stream websocket_deflate_state;
  z_stream websocket_inflate_state;
#endif
  int handled_requests; /* Number of requests handled by this connection
                         */
  int buf_size;         /* Buffer size */
  int request_len;      /* Size of the request + headers in a buffer */
  int data_len;         /* Total size of data in a buffer */
  int status_code;      /* HTTP reply status code, e.g. 200 */
  int throttle;         /* Throttling, bytes/sec. <= 0 means no
                         * throttle */

  time_t last_throttle_time; /* Last time throttled data was sent */
  int last_throttle_bytes;   /* Bytes sent this second */
  pthread_mutex_t mutex;     /* Used by mg_(un)lock_connection to ensure
                              * atomic transmissions for websockets */
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  void *lua_websocket_state; /* Lua_State for a websocket connection */
#endif

  void *tls_user_ptr; /* User defined pointer in thread local storage,
                       * for quick access */
};


/* Directory entry */
struct de {
  char *file_name;
  struct mg_file_stat file;
};


#define mg_cry_internal(conn, fmt, ...)                                        \
  mg_cry_internal_wrap(conn, NULL, __func__, __LINE__, fmt, __VA_ARGS__)

#define mg_cry_ctx_internal(ctx, fmt, ...)                                     \
  mg_cry_internal_wrap(NULL, ctx, __func__, __LINE__, fmt, __VA_ARGS__)

static void mg_cry_internal_wrap(const struct mg_connection *conn,
                                 struct mg_context *ctx,
                                 const char *func,
                                 unsigned line,
                                 const char *fmt,
                                 ...) PRINTF_ARGS(5, 6);


#if !defined(NO_THREAD_NAME)
#if defined(_WIN32) && defined(_MSC_VER)
/* Set the thread name for debugging purposes in Visual Studio
 * http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
 */
#pragma pack(push, 8)
typedef struct tagTHREADNAME_INFO {
  DWORD dwType;     /* Must be 0x1000. */
  LPCSTR szName;    /* Pointer to name (in user addr space). */
  DWORD dwThreadID; /* Thread ID (-1=caller thread). */
  DWORD dwFlags;    /* Reserved for future use, must be zero. */
} THREADNAME_INFO;
#pragma pack(pop)

#elif defined(__linux__)

#include <sys/prctl.h>
#include <sys/sendfile.h>
#if defined(ALTERNATIVE_QUEUE)
#include <sys/eventfd.h>
#endif /* ALTERNATIVE_QUEUE */


#if defined(ALTERNATIVE_QUEUE)

static void *
event_create(void)
{
  int evhdl = eventfd(0, EFD_CLOEXEC);
  int *ret;

  if (evhdl == -1) {
    /* Linux uses -1 on error, Windows NULL. */
    /* However, Linux does not return 0 on success either. */
    return 0;
  }

  ret = (int *)mg_malloc(sizeof(int));
  if (ret) {
    *ret = evhdl;
  } else {
    (void)close(evhdl);
  }

  return (void *)ret;
}


static int
event_wait(void *eventhdl)
{
  uint64_t u;
  int evhdl, s;

  if (!eventhdl) {
    /* error */
    return 0;
  }
  evhdl = *(int *)eventhdl;

  s = (int)read(evhdl, &u, sizeof(u));
  if (s != sizeof(u)) {
    /* error */
    return 0;
  }
  (void)u; /* the value is not required */
  return 1;
}


static int
event_signal(void *eventhdl)
{
  uint64_t u = 1;
  int evhdl, s;

  if (!eventhdl) {
    /* error */
    return 0;
  }
  evhdl = *(int *)eventhdl;

  s = (int)write(evhdl, &u, sizeof(u));
  if (s != sizeof(u)) {
    /* error */
    return 0;
  }
  return 1;
}


static void
event_destroy(void *eventhdl)
{
  int evhdl;

  if (!eventhdl) {
    /* error */
    return;
  }
  evhdl = *(int *)eventhdl;

  close(evhdl);
  mg_free(eventhdl);
}


#endif

#endif


#if !defined(__linux__) && !defined(_WIN32) && defined(ALTERNATIVE_QUEUE)

struct posix_event {
  pthread_mutex_t mutex;
  pthread_cond_t cond;
  int signaled;
};


static void *
event_create(void)
{
  struct posix_event *ret = mg_malloc(sizeof(struct posix_event));
  if (ret == 0) {
    /* out of memory */
    return 0;
  }
  if (0 != pthread_mutex_init(&(ret->mutex), NULL)) {
    /* pthread mutex not available */
    mg_free(ret);
    return 0;
  }
  if (0 != pthread_cond_init(&(ret->cond), NULL)) {
    /* pthread cond not available */
    pthread_mutex_destroy(&(ret->mutex));
    mg_free(ret);
    return 0;
  }
  ret->signaled = 0;
  return (void *)ret;
}


static int
event_wait(void *eventhdl)
{
  struct posix_event *ev = (struct posix_event *)eventhdl;
  pthread_mutex_lock(&(ev->mutex));
  while (!ev->signaled) {
    pthread_cond_wait(&(ev->cond), &(ev->mutex));
  }
  ev->signaled = 0;
  pthread_mutex_unlock(&(ev->mutex));
  return 1;
}


static int
event_signal(void *eventhdl)
{
  struct posix_event *ev = (struct posix_event *)eventhdl;
  pthread_mutex_lock(&(ev->mutex));
  pthread_cond_signal(&(ev->cond));
  ev->signaled = 1;
  pthread_mutex_unlock(&(ev->mutex));
  return 1;
}


static void
event_destroy(void *eventhdl)
{
  struct posix_event *ev = (struct posix_event *)eventhdl;
  pthread_cond_destroy(&(ev->cond));
  pthread_mutex_destroy(&(ev->mutex));
  mg_free(ev);
}
#endif


static void
mg_set_thread_name(const char *name)
{
  char threadName[16 + 1]; /* 16 = Max. thread length in Linux/OSX/.. */

  mg_snprintf(
      NULL, NULL, threadName, sizeof(threadName), "civetweb-%s", name);

#if defined(_WIN32)
#if defined(_MSC_VER)
  /* Windows and Visual Studio Compiler */
  __try {
    THREADNAME_INFO info;
    info.dwType = 0x1000;
    info.szName = threadName;
    info.dwThreadID = ~0U;
    info.dwFlags = 0;

    RaiseException(0x406D1388,
                   0,
                   sizeof(info) / sizeof(ULONG_PTR),
                   (ULONG_PTR *)&info);
  } __except (EXCEPTION_EXECUTE_HANDLER) {
  }
#elif defined(__MINGW32__)
  /* No option known to set thread name for MinGW known */
#endif
#elif defined(_GNU_SOURCE) && defined(__GLIBC__)                               \
    && ((__GLIBC__ > 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 12)))
  /* pthread_setname_np first appeared in glibc in version 2.12 */
#if defined(__MACH__) && defined(__APPLE__)
  /* OS X only current thread name can be changed */
  (void)pthread_setname_np(threadName);
#else
  (void)pthread_setname_np(pthread_self(), threadName);
#endif
#elif defined(__linux__)
  /* On Linux we can use the prctl function.
   * When building for Linux Standard Base (LSB) use
   * NO_THREAD_NAME. However, thread names are a big
   * help for debugging, so the stadard is to set them.
   */
  (void)prctl(PR_SET_NAME, threadName, 0, 0, 0);
#endif
}
#else /* !defined(NO_THREAD_NAME) */
static void
mg_set_thread_name(const char *threadName)
{
}
#endif


CIVETWEB_API const struct mg_option *
mg_get_valid_options(void)
{
  return config_options;
}


/* Do not open file (unused) */
#define MG_FOPEN_MODE_NONE (0)

/* Open file for read only access */
#define MG_FOPEN_MODE_READ (1)

/* Open file for writing, create and overwrite */
#define MG_FOPEN_MODE_WRITE (2)

/* Open file for writing, create and append */
#define MG_FOPEN_MODE_APPEND (4)


static int
is_file_opened(const struct mg_file_access *fileacc)
{
  if (!fileacc) {
    return 0;
  }

  return (fileacc->fp != NULL);
}


#if !defined(NO_FILESYSTEMS)
static int mg_stat(const struct mg_connection *conn,
                   const char *path,
                   struct mg_file_stat *filep);


/* Reject files with special characters (for Windows) */
static int
mg_path_suspicious(const struct mg_connection *conn, const char *path)
{
  const uint8_t *c = (const uint8_t *)path;
  (void)conn; /* not used */

  if ((c == NULL) || (c[0] == 0)) {
    /* Null pointer or empty path --> suspicious */
    return 1;
  }

#if defined(_WIN32)
  while (*c) {
    if (*c < 32) {
      /* Control character */
      return 1;
    }
    if ((*c == '>') || (*c == '<') || (*c == '|')) {
      /* stdin/stdout redirection character */
      return 1;
    }
    if ((*c == '*') || (*c == '?')) {
      /* Wildcard character */
      return 1;
    }
    if (*c == '"') {
      /* Windows quotation */
      return 1;
    }
    c++;
  }
#endif

  /* Nothing suspicious found */
  return 0;
}


/* mg_fopen will open a file either in memory or on the disk.
 * The input parameter path is a string in UTF-8 encoding.
 * The input parameter mode is MG_FOPEN_MODE_*
 * On success, fp will be set in the output struct mg_file.
 * All status members will also be set.
 * The function returns 1 on success, 0 on error. */
static int
mg_fopen(const struct mg_connection *conn,
         const char *path,
         int mode,
         struct mg_file *filep)
{
  int found;

  if (!filep) {
    return 0;
  }
  filep->access.fp = NULL;

  if (mg_path_suspicious(conn, path)) {
    return 0;
  }

  /* filep is initialized in mg_stat: all fields with memset to,
   * some fields like size and modification date with values */
  found = mg_stat(conn, path, &(filep->stat));

  if ((mode == MG_FOPEN_MODE_READ) && (!found)) {
    /* file does not exist and will not be created */
    return 0;
  }

#if defined(_WIN32)
  {
    wchar_t wbuf[UTF16_PATH_MAX];
    path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
    switch (mode) {
    case MG_FOPEN_MODE_READ:
      filep->access.fp = _wfopen(wbuf, L"rb");
      break;
    case MG_FOPEN_MODE_WRITE:
      filep->access.fp = _wfopen(wbuf, L"wb");
      break;
    case MG_FOPEN_MODE_APPEND:
      filep->access.fp = _wfopen(wbuf, L"ab");
      break;
    }
  }
#else
  /* Linux et al already use unicode. No need to convert. */
  switch (mode) {
  case MG_FOPEN_MODE_READ:
    filep->access.fp = fopen(path, "r");
    break;
  case MG_FOPEN_MODE_WRITE:
    filep->access.fp = fopen(path, "w");
    break;
  case MG_FOPEN_MODE_APPEND:
    filep->access.fp = fopen(path, "a");
    break;
  }

#endif
  if (!found) {
    /* File did not exist before fopen was called.
     * Maybe it has been created now. Get stat info
     * like creation time now. */
    found = mg_stat(conn, path, &(filep->stat));
    (void)found;
  }

  /* return OK if file is opened */
  return (filep->access.fp != NULL);
}


/* return 0 on success, just like fclose */
static int
mg_fclose(struct mg_file_access *fileacc)
{
  int ret = -1;
  if (fileacc != NULL) {
    if (fileacc->fp != NULL) {
      ret = fclose(fileacc->fp);
    }
    /* reset all members of fileacc */
    memset(fileacc, 0, sizeof(*fileacc));
  }
  return ret;
}
#endif /* NO_FILESYSTEMS */


static void
mg_strlcpy(char *dst, const char *src, size_t n)
{
  for (; *src != '\0' && n > 1; n--) {
    *dst++ = *src++;
  }
  *dst = '\0';
}


static int
lowercase(const char *s)
{
  return tolower((unsigned char)*s);
}


CIVETWEB_API int
mg_strncasecmp(const char *s1, const char *s2, size_t len)
{
  int diff = 0;

  if (len > 0) {
    do {
      diff = lowercase(s1++) - lowercase(s2++);
    } while (diff == 0 && s1[-1] != '\0' && --len > 0);
  }

  return diff;
}


CIVETWEB_API int
mg_strcasecmp(const char *s1, const char *s2)
{
  int diff;

  do {
    diff = lowercase(s1++) - lowercase(s2++);
  } while (diff == 0 && s1[-1] != '\0');

  return diff;
}


static char *
mg_strndup_ctx(const char *ptr, size_t len, struct mg_context *ctx)
{
  char *p;
  (void)ctx; /* Avoid Visual Studio warning if USE_SERVER_STATS is not
              * defined */

  if ((p = (char *)mg_malloc_ctx(len + 1, ctx)) != NULL) {
    mg_strlcpy(p, ptr, len + 1);
  }

  return p;
}


static char *
mg_strdup_ctx(const char *str, struct mg_context *ctx)
{
  return mg_strndup_ctx(str, strlen(str), ctx);
}

static char *
mg_strdup(const char *str)
{
  return mg_strndup_ctx(str, strlen(str), NULL);
}


static const char *
mg_strcasestr(const char *big_str, const char *small_str)
{
  size_t i, big_len = strlen(big_str), small_len = strlen(small_str);

  if (big_len >= small_len) {
    for (i = 0; i <= (big_len - small_len); i++) {
      if (mg_strncasecmp(big_str + i, small_str, small_len) == 0) {
        return big_str + i;
      }
    }
  }

  return NULL;
}


/* Return null terminated string of given maximum length.
 * Report errors if length is exceeded. */
static void
mg_vsnprintf(const struct mg_connection *conn,
             int *truncated,
             char *buf,
             size_t buflen,
             const char *fmt,
             va_list ap)
{
  int n, ok;

  if (buflen == 0) {
    if (truncated) {
      *truncated = 1;
    }
    return;
  }

#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wformat-nonliteral"
  /* Using fmt as a non-literal is intended here, since it is mostly called
   * indirectly by mg_snprintf */
#endif

  n = (int)vsnprintf_impl(buf, buflen, fmt, ap);
  ok = (n >= 0) && ((size_t)n < buflen);

#if defined(__clang__)
#pragma clang diagnostic pop
#endif

  if (ok) {
    if (truncated) {
      *truncated = 0;
    }
  } else {
    if (truncated) {
      *truncated = 1;
    }
    mg_cry_internal(conn,
                    "truncating vsnprintf buffer: [%.*s]",
                    (int)((buflen > 200) ? 200 : (buflen - 1)),
                    buf);
    n = (int)buflen - 1;
  }
  buf[n] = '\0';
}


static void
mg_snprintf(const struct mg_connection *conn,
            int *truncated,
            char *buf,
            size_t buflen,
            const char *fmt,
            ...)
{
  va_list ap;

  va_start(ap, fmt);
  mg_vsnprintf(conn, truncated, buf, buflen, fmt, ap);
  va_end(ap);
}


static int
get_option_index(const char *name)
{
  int i;

  for (i = 0; config_options[i].name != NULL; i++) {
    if (strcmp(config_options[i].name, name) == 0) {
      return i;
    }
  }
  return -1;
}


CIVETWEB_API const char *
mg_get_option(const struct mg_context *ctx, const char *name)
{
  int i;
  if ((i = get_option_index(name)) == -1) {
    return NULL;
  } else if (!ctx || ctx->dd.config[i] == NULL) {
    return "";
  } else {
    return ctx->dd.config[i];
  }
}

#define mg_get_option DO_NOT_USE_THIS_FUNCTION_INTERNALLY__access_directly

CIVETWEB_API struct mg_context *
mg_get_context(const struct mg_connection *conn)
{
  return (conn == NULL) ? (struct mg_context *)NULL : (conn->phys_ctx);
}


CIVETWEB_API void *
mg_get_user_data(const struct mg_context *ctx)
{
  return (ctx == NULL) ? NULL : ctx->user_data;
}


CIVETWEB_API void *
mg_get_user_context_data(const struct mg_connection *conn)
{
  return mg_get_user_data(mg_get_context(conn));
}


CIVETWEB_API void *
mg_get_thread_pointer(const struct mg_connection *conn)
{
  /* both methods should return the same pointer */
  if (conn) {
    /* quick access, in case conn is known */
    return conn->tls_user_ptr;
  } else {
    /* otherwise get pointer from thread local storage (TLS) */
    struct mg_workerTLS *tls =
        (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
    return tls->user_ptr;
  }
}


CIVETWEB_API void
mg_set_user_connection_data(const struct mg_connection *const_conn, void *data)
{
  if (const_conn != NULL) {
    /* Const cast, since "const struct mg_connection *" does not mean
     * the connection object is not modified. Here "const" is used,
     * to indicate mg_read/mg_write/mg_send/.. must not be called. */
    struct mg_connection *conn = (struct mg_connection *)const_conn;
    conn->request_info.conn_data = data;
  }
}


CIVETWEB_API void *
mg_get_user_connection_data(const struct mg_connection *conn)
{
  if (conn != NULL) {
    return conn->request_info.conn_data;
  }
  return NULL;
}


CIVETWEB_API int
mg_get_server_ports(const struct mg_context *ctx,
                    int size,
                    struct mg_server_port *ports)
{
  int i, cnt = 0;

  if (size <= 0) {
    return -1;
  }
  memset(ports, 0, sizeof(*ports) * (size_t)size);
  if (!ctx) {
    return -1;
  }
  if (!ctx->listening_sockets) {
    return -1;
  }

  for (i = 0; (i < size) && (i < (int)ctx->num_listening_sockets); i++) {

    ports[cnt].port =
        ntohs(USA_IN_PORT_UNSAFE(&(ctx->listening_sockets[i].lsa)));
    ports[cnt].is_ssl = ctx->listening_sockets[i].is_ssl;
    ports[cnt].is_redirect = ctx->listening_sockets[i].ssl_redir;

    if (ctx->listening_sockets[i].lsa.sa.sa_family == AF_INET) {
      /* IPv4 */
      ports[cnt].protocol = 1;
      cnt++;
    } else if (ctx->listening_sockets[i].lsa.sa.sa_family == AF_INET6) {
      /* IPv6 */
      ports[cnt].protocol = 3;
      cnt++;
    }
  }

  return cnt;
}


#if defined(USE_X_DOM_SOCKET) && !defined(UNIX_DOMAIN_SOCKET_SERVER_NAME)
#define UNIX_DOMAIN_SOCKET_SERVER_NAME "*"
#endif

static void
sockaddr_to_string(char *buf, size_t len, const union usa *usa)
{
  buf[0] = '\0';

  if (!usa) {
    return;
  }

  if (usa->sa.sa_family == AF_INET) {
    getnameinfo(&usa->sa,
                sizeof(usa->sin),
                buf,
                (unsigned)len,
                NULL,
                0,
                NI_NUMERICHOST);
  }
#if defined(USE_IPV6)
  else if (usa->sa.sa_family == AF_INET6) {
    getnameinfo(&usa->sa,
                sizeof(usa->sin6),
                buf,
                (unsigned)len,
                NULL,
                0,
                NI_NUMERICHOST);
  }
#endif
#if defined(USE_X_DOM_SOCKET)
  else if (usa->sa.sa_family == AF_UNIX) {
    /* TODO: Define a remote address for unix domain sockets.
    * This code will always return "localhost", identical to http+tcp:
    getnameinfo(&usa->sa,
    sizeof(usa->sun),
    buf,
    (unsigned)len,
    NULL,
    0,
    NI_NUMERICHOST);
    */
    mg_strlcpy(buf, UNIX_DOMAIN_SOCKET_SERVER_NAME, len);
  }
#endif
}


/* Convert time_t to a string. According to RFC2616, Sec 14.18, this must be
 * included in all responses other than 100, 101, 5xx. */
static void
gmt_time_string(char *buf, size_t buf_len, time_t *t)
{
#if !defined(REENTRANT_TIME)
  struct tm *tm;

  tm = ((t != NULL) ? gmtime(t) : NULL);
  if (tm != NULL) {
#else
  struct tm _tm;
  struct tm *tm = &_tm;

  if (t != NULL) {
    gmtime_r(t, tm);
#endif
    strftime(buf, buf_len, "%a, %d %b %Y %H:%M:%S GMT", tm);
  } else {
    mg_strlcpy(buf, "Thu, 01 Jan 1970 00:00:00 GMT", buf_len);
  }
}


/* difftime for struct timespec. Return value is in seconds. */
static double
mg_difftimespec(const struct timespec *ts_now, const struct timespec *ts_before)
{
  return (double)(ts_now->tv_nsec - ts_before->tv_nsec) * 1.0E-9
         + (double)(ts_now->tv_sec - ts_before->tv_sec);
}


#if defined(MG_EXTERNAL_FUNCTION_mg_cry_internal_impl)
static void mg_cry_internal_impl(const struct mg_connection *conn,
                                 const char *func,
                                 unsigned line,
                                 const char *fmt,
                                 va_list ap);
#include "external_mg_cry_internal_impl.inl"
#elif !defined(NO_FILESYSTEMS)

/* Print error message to the opened error log stream. */
static void
mg_cry_internal_impl(const struct mg_connection *conn,
                     const char *func,
                     unsigned line,
                     const char *fmt,
                     va_list ap)
{
  char buf[MG_BUF_LEN], src_addr[IP_ADDR_STR_LEN];
  struct mg_file fi;
  time_t timestamp;

  /* Unused, in the RELEASE build */
  (void)func;
  (void)line;

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif

  IGNORE_UNUSED_RESULT(vsnprintf_impl(buf, sizeof(buf), fmt, ap));

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif

  buf[sizeof(buf) - 1] = 0;

  DEBUG_TRACE("mg_cry called from %s:%u: %s", func, line, buf);

  if (!conn) {
    puts(buf);
    return;
  }

  /* Do not lock when getting the callback value, here and below.
   * I suppose this is fine, since function cannot disappear in the
   * same way string option can. */
  if ((conn->phys_ctx->callbacks.log_message == NULL)
      || (conn->phys_ctx->callbacks.log_message(conn, buf) == 0)) {

    if (conn->dom_ctx->config[ERROR_LOG_FILE] != NULL) {
      if (mg_fopen(conn,
                   conn->dom_ctx->config[ERROR_LOG_FILE],
                   MG_FOPEN_MODE_APPEND,
                   &fi)
          == 0) {
        fi.access.fp = NULL;
      }
    } else {
      fi.access.fp = NULL;
    }

    if (fi.access.fp != NULL) {
      flockfile(fi.access.fp);
      timestamp = time(NULL);

      sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
      fprintf(fi.access.fp,
              "[%010lu] [error] [client %s] ",
              (unsigned long)timestamp,
              src_addr);

      if (conn->request_info.request_method != NULL) {
        fprintf(fi.access.fp,
                "%s %s: ",
                conn->request_info.request_method,
                conn->request_info.request_uri
                    ? conn->request_info.request_uri
                    : "");
      }

      fprintf(fi.access.fp, "%s", buf);
      fputc('\n', fi.access.fp);
      fflush(fi.access.fp);
      funlockfile(fi.access.fp);
      (void)mg_fclose(&fi.access); /* Ignore errors. We can't call
                                    * mg_cry here anyway ;-) */
    }
  }
}
#else
#error Must either enable filesystems or provide a custom mg_cry_internal_impl implementation
#endif /* Externally provided function */


/* Construct fake connection structure. Used for logging, if connection
 * is not applicable at the moment of logging. */
static struct mg_connection *
fake_connection(struct mg_connection *fc, struct mg_context *ctx)
{
  static const struct mg_connection conn_zero = {0};
  *fc = conn_zero;
  fc->phys_ctx = ctx;
  fc->dom_ctx = &(ctx->dd);
  return fc;
}


static void
mg_cry_internal_wrap(const struct mg_connection *conn,
                     struct mg_context *ctx,
                     const char *func,
                     unsigned line,
                     const char *fmt,
                     ...)
{
  va_list ap;
  va_start(ap, fmt);
  if (!conn && ctx) {
    struct mg_connection fc;
    mg_cry_internal_impl(fake_connection(&fc, ctx), func, line, fmt, ap);
  } else {
    mg_cry_internal_impl(conn, func, line, fmt, ap);
  }
  va_end(ap);
}


CIVETWEB_API void
mg_cry(const struct mg_connection *conn, const char *fmt, ...)
{
  va_list ap;
  va_start(ap, fmt);
  mg_cry_internal_impl(conn, "user", 0, fmt, ap);
  va_end(ap);
}


#define mg_cry DO_NOT_USE_THIS_FUNCTION__USE_mg_cry_internal


CIVETWEB_API const char *
mg_version(void)
{
  return CIVETWEB_VERSION;
}


CIVETWEB_API const struct mg_request_info *
mg_get_request_info(const struct mg_connection *conn)
{
  if (!conn) {
    return NULL;
  }
#if defined(MG_ALLOW_USING_GET_REQUEST_INFO_FOR_RESPONSE)
  if (conn->connection_type == CONNECTION_TYPE_RESPONSE) {
    char txt[16];
    struct mg_workerTLS *tls =
        (struct mg_workerTLS *)pthread_getspecific(sTlsKey);

    sprintf(txt, "%03i", conn->response_info.status_code);
    if (strlen(txt) == 3) {
      memcpy(tls->txtbuf, txt, 4);
    } else {
      strcpy(tls->txtbuf, "ERR");
    }

    ((struct mg_connection *)conn)->request_info.local_uri =
        tls->txtbuf; /* use thread safe buffer */
    ((struct mg_connection *)conn)->request_info.local_uri_raw =
        tls->txtbuf; /* use the same thread safe buffer */
    ((struct mg_connection *)conn)->request_info.request_uri =
        tls->txtbuf; /* use  the same thread safe buffer */

    ((struct mg_connection *)conn)->request_info.num_headers =
        conn->response_info.num_headers;
    memcpy(((struct mg_connection *)conn)->request_info.http_headers,
           conn->response_info.http_headers,
           sizeof(conn->response_info.http_headers));
  } else
#endif
      if (conn->connection_type != CONNECTION_TYPE_REQUEST) {
    return NULL;
  }
  return &conn->request_info;
}


CIVETWEB_API const struct mg_response_info *
mg_get_response_info(const struct mg_connection *conn)
{
  if (!conn) {
    return NULL;
  }
  if (conn->connection_type != CONNECTION_TYPE_RESPONSE) {
    return NULL;
  }
  return &conn->response_info;
}


static const char *
get_proto_name(const struct mg_connection *conn)
{
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
  /* Depending on USE_WEBSOCKET and NO_SSL, some oft the protocols might be
   * not supported. Clang raises an "unreachable code" warning for parts of ?:
   * unreachable, but splitting into four different #ifdef clauses here is
   * more complicated.
   */
#endif

  const struct mg_request_info *ri = &conn->request_info;

  const char *proto = ((conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET)
                           ? (ri->is_ssl ? "wss" : "ws")
                           : (ri->is_ssl ? "https" : "http"));

  return proto;

#if defined(__clang__)
#pragma clang diagnostic pop
#endif
}


static int
mg_construct_local_link(const struct mg_connection *conn,
                        char *buf,
                        size_t buflen,
                        const char *define_proto,
                        int define_port,
                        const char *define_uri)
{
  if ((buflen < 1) || (buf == 0) || (conn == 0)) {
    return -1;
  } else {
    int i, j;
    int truncated = 0;
    const struct mg_request_info *ri = &conn->request_info;

    const char *proto =
        (define_proto != NULL) ? define_proto : get_proto_name(conn);
    const char *uri =
        (define_uri != NULL)
            ? define_uri
            : ((ri->request_uri != NULL) ? ri->request_uri : ri->local_uri);
    int port = (define_port > 0) ? define_port : ri->server_port;
    int default_port = 80;
    char *uri_encoded;
    size_t uri_encoded_len;

    if (uri == NULL) {
      return -1;
    }

    uri_encoded_len = strlen(uri) * 3 + 1;
    uri_encoded = (char *)mg_malloc_ctx(uri_encoded_len, conn->phys_ctx);
    if (uri_encoded == NULL) {
      return -1;
    }
    mg_url_encode(uri, uri_encoded, uri_encoded_len);

    /* Directory separator should be preserved. */
    for (i = j = 0; uri_encoded[i]; j++) {
      if (!strncmp(uri_encoded + i, "%2f", 3)) {
        uri_encoded[j] = '/';
        i += 3;
      } else {
        uri_encoded[j] = uri_encoded[i++];
      }
    }
    uri_encoded[j] = '\0';

#if defined(USE_X_DOM_SOCKET)
    if (conn->client.lsa.sa.sa_family == AF_UNIX) {
      /* TODO: Define and document a link for UNIX domain sockets. */
      /* There seems to be no official standard for this.
       * Common uses seem to be "httpunix://", "http.unix://" or
       * "http+unix://" as a protocol definition string, followed by
       * "localhost" or "127.0.0.1" or "/tmp/unix/path" or
       * "%2Ftmp%2Funix%2Fpath" (url % encoded) or
       * "localhost:%2Ftmp%2Funix%2Fpath" (domain socket path as port) or
       * "" (completely skipping the server name part). In any case, the
       * last part is the server local path. */
      const char *server_name = UNIX_DOMAIN_SOCKET_SERVER_NAME;
      mg_snprintf(conn,
                  &truncated,
                  buf,
                  buflen,
                  "%s.unix://%s%s",
                  proto,
                  server_name,
                  ri->local_uri);
      default_port = 0;
      mg_free(uri_encoded);
      return 0;
    }
#endif

    if (define_proto) {
      /* If we got a protocol name, use the default port accordingly. */
      if ((0 == strcmp(define_proto, "https"))
          || (0 == strcmp(define_proto, "wss"))) {
        default_port = 443;
      }
    } else if (ri->is_ssl) {
      /* If we did not get a protocol name, use TLS as default if it is
       * already used. */
      default_port = 443;
    }

    {
#if defined(USE_IPV6)
      int is_ipv6 = (conn->client.lsa.sa.sa_family == AF_INET6);
#endif
      int auth_domain_check_enabled =
          conn->dom_ctx->config[ENABLE_AUTH_DOMAIN_CHECK]
          && (!mg_strcasecmp(
                 conn->dom_ctx->config[ENABLE_AUTH_DOMAIN_CHECK], "yes"));

      const char *server_domain =
          conn->dom_ctx->config[AUTHENTICATION_DOMAIN];

      char portstr[16];
      char server_ip[48];

      if (port != default_port) {
        sprintf(portstr, ":%u", (unsigned)port);
      } else {
        portstr[0] = 0;
      }

      if (!auth_domain_check_enabled || !server_domain) {

        sockaddr_to_string(server_ip,
                           sizeof(server_ip),
                           &conn->client.lsa);

        server_domain = server_ip;
      }

      mg_snprintf(conn,
                  &truncated,
                  buf,
                  buflen,
#if defined(USE_IPV6)
                  "%s://%s%s%s%s%s",
                  proto,
                  (is_ipv6 && (server_domain == server_ip)) ? "[" : "",
                  server_domain,
                  (is_ipv6 && (server_domain == server_ip)) ? "]" : "",
#else
                  "%s://%s%s%s",
                  proto,
                  server_domain,
#endif
                  portstr,
                  uri_encoded);

      mg_free(uri_encoded);
      if (truncated) {
        return -1;
      }
      return 0;
    }
  }
}


CIVETWEB_API int
mg_get_request_link(const struct mg_connection *conn, char *buf, size_t buflen)
{
  return mg_construct_local_link(conn, buf, buflen, NULL, -1, NULL);
}


/* Skip the characters until one of the delimiters characters found.
 * 0-terminate resulting word. Skip the delimiter and following whitespaces.
 * Advance pointer to buffer to the next word. Return found 0-terminated
 * word.
 * Delimiters can be quoted with quotechar. */
static char *
skip_quoted(char **buf,
            const char *delimiters,
            const char *whitespace,
            char quotechar)
{
  char *p, *begin_word, *end_word, *end_whitespace;

  begin_word = *buf;
  end_word = begin_word + strcspn(begin_word, delimiters);

  /* Check for quotechar */
  if (end_word > begin_word) {
    p = end_word - 1;
    while (*p == quotechar) {
      /* While the delimiter is quoted, look for the next delimiter. */
      /* This happens, e.g., in calls from parse_auth_header,
       * if the user name contains a " character. */

      /* If there is anything beyond end_word, copy it. */
      if (*end_word != '\0') {
        size_t end_off = strcspn(end_word + 1, delimiters);
        memmove(p, end_word, end_off + 1);
        p += end_off; /* p must correspond to end_word - 1 */
        end_word += end_off + 1;
      } else {
        *p = '\0';
        break;
      }
    }
    for (p++; p < end_word; p++) {
      *p = '\0';
    }
  }

  if (*end_word == '\0') {
    *buf = end_word;
  } else {

#if defined(GCC_DIAGNOSTIC)
    /* Disable spurious conversion warning for GCC */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsign-conversion"
#endif /* defined(GCC_DIAGNOSTIC) */

    end_whitespace = end_word + strspn(&end_word[1], whitespace) + 1;

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */

    for (p = end_word; p < end_whitespace; p++) {
      *p = '\0';
    }

    *buf = end_whitespace;
  }

  return begin_word;
}


/* Return HTTP header value, or NULL if not found. */
static const char *
get_header(const struct mg_header *hdr, int num_hdr, const char *name)
{
  int i;
  for (i = 0; i < num_hdr; i++) {
    if (!mg_strcasecmp(name, hdr[i].name)) {
      return hdr[i].value;
    }
  }

  return NULL;
}


/* Retrieve requested HTTP header multiple values, and return the number of
 * found occurrences */
static int
get_req_headers(const struct mg_request_info *ri,
                const char *name,
                const char **output,
                int output_max_size)
{
  int i;
  int cnt = 0;
  if (ri) {
    for (i = 0; i < ri->num_headers && cnt < output_max_size; i++) {
      if (!mg_strcasecmp(name, ri->http_headers[i].name)) {
        output[cnt++] = ri->http_headers[i].value;
      }
    }
  }
  return cnt;
}


CIVETWEB_API const char *
mg_get_header(const struct mg_connection *conn, const char *name)
{
  if (!conn) {
    return NULL;
  }

  if (conn->connection_type == CONNECTION_TYPE_REQUEST) {
    return get_header(conn->request_info.http_headers,
                      conn->request_info.num_headers,
                      name);
  }
  if (conn->connection_type == CONNECTION_TYPE_RESPONSE) {
    return get_header(conn->response_info.http_headers,
                      conn->response_info.num_headers,
                      name);
  }
  return NULL;
}


static const char *
get_http_version(const struct mg_connection *conn)
{
  if (!conn) {
    return NULL;
  }

  if (conn->connection_type == CONNECTION_TYPE_REQUEST) {
    return conn->request_info.http_version;
  }
  if (conn->connection_type == CONNECTION_TYPE_RESPONSE) {
    return conn->response_info.http_version;
  }
  return NULL;
}


/* A helper function for traversing a comma separated list of values.
 * It returns a list pointer shifted to the next value, or NULL if the end
 * of the list found.
 * Value is stored in val vector. If value has form "x=y", then eq_val
 * vector is initialized to point to the "y" part, and val vector length
 * is adjusted to point only to "x". */
static const char *
next_option(const char *list, struct vec *val, struct vec *eq_val)
{
  int end;

reparse:
  if (val == NULL || list == NULL || *list == '\0') {
    /* End of the list */
    return NULL;
  }

  /* Skip over leading LWS */
  while (*list == ' ' || *list == '\t')
    list++;

  val->ptr = list;
  if ((list = strchr(val->ptr, ',')) != NULL) {
    /* Comma found. Store length and shift the list ptr */
    val->len = ((size_t)(list - val->ptr));
    list++;
  } else {
    /* This value is the last one */
    list = val->ptr + strlen(val->ptr);
    val->len = ((size_t)(list - val->ptr));
  }

  /* Adjust length for trailing LWS */
  end = (int)val->len - 1;
  while (end >= 0 && ((val->ptr[end] == ' ') || (val->ptr[end] == '\t')))
    end--;
  val->len = (size_t)(end) + (size_t)(1);

  if (val->len == 0) {
    /* Ignore any empty entries. */
    goto reparse;
  }

  if (eq_val != NULL) {
    /* Value has form "x=y", adjust pointers and lengths
     * so that val points to "x", and eq_val points to "y". */
    eq_val->len = 0;
    eq_val->ptr = (const char *)memchr(val->ptr, '=', val->len);
    if (eq_val->ptr != NULL) {
      eq_val->ptr++; /* Skip over '=' character */
      eq_val->len = ((size_t)(val->ptr - eq_val->ptr)) + val->len;
      val->len = ((size_t)(eq_val->ptr - val->ptr)) - 1;
    }
  }

  return list;
}


/* A helper function for checking if a comma separated list of values
 * contains
 * the given option (case insensitvely).
 * 'header' can be NULL, in which case false is returned. */
static int
header_has_option(const char *header, const char *option)
{
  struct vec opt_vec;
  struct vec eq_vec;

  DEBUG_ASSERT(option != NULL);
  DEBUG_ASSERT(option[0] != '\0');

  while ((header = next_option(header, &opt_vec, &eq_vec)) != NULL) {
    if (mg_strncasecmp(option, opt_vec.ptr, opt_vec.len) == 0)
      return 1;
  }

  return 0;
}


/* Sorting function implemented in a separate file */
#include "sort.inl"

/* Pattern matching has been reimplemented in a new file */
#include "match.inl"


/* HTTP 1.1 assumes keep alive if "Connection:" header is not set
 * This function must tolerate situations when connection info is not
 * set up, for example if request parsing failed. */
static int
should_keep_alive(const struct mg_connection *conn)
{
  const char *http_version;
  const char *header;

  /* First satisfy needs of the server */
  if ((conn == NULL) || conn->must_close) {
    /* Close, if civetweb framework needs to close */
    return 0;
  }

  if (mg_strcasecmp(conn->dom_ctx->config[ENABLE_KEEP_ALIVE], "yes") != 0) {
    /* Close, if keep alive is not enabled */
    return 0;
  }

  /* Check explicit wish of the client */
  header = mg_get_header(conn, "Connection");
  if (header) {
    /* If there is a connection header from the client, obey */
    if (header_has_option(header, "keep-alive")) {
      return 1;
    }
    return 0;
  }

  /* Use default of the standard */
  http_version = get_http_version(conn);
  if (http_version && (0 == strcmp(http_version, "1.1"))) {
    /* HTTP 1.1 default is keep alive */
    return 1;
  }

  /* HTTP 1.0 (and earlier) default is to close the connection */
  return 0;
}


static int
should_decode_url(const struct mg_connection *conn)
{
  if (!conn || !conn->dom_ctx) {
    return 0;
  }

  return (mg_strcasecmp(conn->dom_ctx->config[DECODE_URL], "yes") == 0);
}


static int
should_decode_query_string(const struct mg_connection *conn)
{
  if (!conn || !conn->dom_ctx) {
    return 0;
  }

  return (mg_strcasecmp(conn->dom_ctx->config[DECODE_QUERY_STRING], "yes")
          == 0);
}


static const char *
suggest_connection_header(const struct mg_connection *conn)
{
  return should_keep_alive(conn) ? "keep-alive" : "close";
}


#include "response.inl"


static void
send_no_cache_header(struct mg_connection *conn)
{
  /* Send all current and obsolete cache opt-out directives. */
  mg_response_header_add(conn,
                         "Cache-Control",
                         "no-cache, no-store, "
                         "must-revalidate, private, max-age=0",
                         -1);
  mg_response_header_add(conn, "Expires", "0", -1);

  if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
    /* Obsolete, but still send it for HTTP/1.0 */
    mg_response_header_add(conn, "Pragma", "no-cache", -1);
  }
}


static void
send_static_cache_header(struct mg_connection *conn)
{
#if !defined(NO_CACHING)
  int max_age;
  char val[64];

  const char *cache_control =
      conn->dom_ctx->config[STATIC_FILE_CACHE_CONTROL];

  /* If there is a full cache-control option configured,0 use it */
  if (cache_control != NULL) {
    mg_response_header_add(conn, "Cache-Control", cache_control, -1);
    return;
  }

  /* Read the server config to check how long a file may be cached.
   * The configuration is in seconds. */
  max_age = atoi(conn->dom_ctx->config[STATIC_FILE_MAX_AGE]);
  if (max_age <= 0) {
    /* 0 means "do not cache". All values <0 are reserved
     * and may be used differently in the future. */
    /* If a file should not be cached, do not only send
     * max-age=0, but also pragmas and Expires headers. */
    send_no_cache_header(conn);
    return;
  }

  /* Use "Cache-Control: max-age" instead of "Expires" header.
   * Reason: see https://www.mnot.net/blog/2007/05/15/expires_max-age */
  /* See also https://www.mnot.net/cache_docs/ */
  /* According to RFC 2616, Section 14.21, caching times should not exceed
   * one year. A year with 365 days corresponds to 31536000 seconds, a
   * leap
   * year to 31622400 seconds. For the moment, we just send whatever has
   * been configured, still the behavior for >1 year should be considered
   * as undefined. */
  mg_snprintf(
      conn, NULL, val, sizeof(val), "max-age=%lu", (unsigned long)max_age);
  mg_response_header_add(conn, "Cache-Control", val, -1);

#else  /* NO_CACHING */

  send_no_cache_header(conn);
#endif /* !NO_CACHING */
}


static void
send_additional_header(struct mg_connection *conn)
{
  const char *header = conn->dom_ctx->config[ADDITIONAL_HEADER];

#if !defined(NO_SSL)
  if (conn->dom_ctx->config[STRICT_HTTPS_MAX_AGE]) {
    long max_age = atol(conn->dom_ctx->config[STRICT_HTTPS_MAX_AGE]);
    if (max_age >= 0) {
      char val[64];
      mg_snprintf(conn,
                  NULL,
                  val,
                  sizeof(val),
                  "max-age=%lu",
                  (unsigned long)max_age);
      mg_response_header_add(conn, "Strict-Transport-Security", val, -1);
    }
  }
#endif

  if (header && header[0]) {
    mg_response_header_add_lines(conn, header);
  }
}


static void
send_cors_header(struct mg_connection *conn)
{
  const char *origin_hdr = mg_get_header(conn, "Origin");
  const char *cors_orig_cfg =
      conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_ORIGIN];

  if (cors_orig_cfg && *cors_orig_cfg && origin_hdr && *origin_hdr) {
    /* Cross-origin resource sharing (CORS), see
     * http://www.html5rocks.com/en/tutorials/cors/,
     * http://www.html5rocks.com/static/images/cors_server_flowchart.png
     * CORS preflight is not supported for files. */
    mg_response_header_add(conn,
                           "Access-Control-Allow-Origin",
                           cors_orig_cfg,
                           -1);
  }
}


#if !defined(NO_FILESYSTEMS)
static void handle_file_based_request(struct mg_connection *conn,
                                      const char *path,
                                      struct mg_file *filep);
#endif /* NO_FILESYSTEMS */


CIVETWEB_API const char *
mg_get_response_code_text(const struct mg_connection *conn, int response_code)
{
  /* See IANA HTTP status code assignment:
   * http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
   */

  switch (response_code) {
    /* RFC2616 Section 10.1 - Informational 1xx */
  case 100:
    return "Continue"; /* RFC2616 Section 10.1.1 */
  case 101:
    return "Switching Protocols"; /* RFC2616 Section 10.1.2 */
  case 102:
    return "Processing"; /* RFC2518 Section 10.1 */

    /* RFC2616 Section 10.2 - Successful 2xx */
  case 200:
    return "OK"; /* RFC2616 Section 10.2.1 */
  case 201:
    return "Created"; /* RFC2616 Section 10.2.2 */
  case 202:
    return "Accepted"; /* RFC2616 Section 10.2.3 */
  case 203:
    return "Non-Authoritative Information"; /* RFC2616 Section 10.2.4 */
  case 204:
    return "No Content"; /* RFC2616 Section 10.2.5 */
  case 205:
    return "Reset Content"; /* RFC2616 Section 10.2.6 */
  case 206:
    return "Partial Content"; /* RFC2616 Section 10.2.7 */
  case 207:
    return "Multi-Status"; /* RFC2518 Section 10.2, RFC4918 Section 11.1
                            */
  case 208:
    return "Already Reported"; /* RFC5842 Section 7.1 */

  case 226:
    return "IM used"; /* RFC3229 Section 10.4.1 */

    /* RFC2616 Section 10.3 - Redirection 3xx */
  case 300:
    return "Multiple Choices"; /* RFC2616 Section 10.3.1 */
  case 301:
    return "Moved Permanently"; /* RFC2616 Section 10.3.2 */
  case 302:
    return "Found"; /* RFC2616 Section 10.3.3 */
  case 303:
    return "See Other"; /* RFC2616 Section 10.3.4 */
  case 304:
    return "Not Modified"; /* RFC2616 Section 10.3.5 */
  case 305:
    return "Use Proxy"; /* RFC2616 Section 10.3.6 */
  case 307:
    return "Temporary Redirect"; /* RFC2616 Section 10.3.8 */
  case 308:
    return "Permanent Redirect"; /* RFC7238 Section 3 */

    /* RFC2616 Section 10.4 - Client Error 4xx */
  case 400:
    return "Bad Request"; /* RFC2616 Section 10.4.1 */
  case 401:
    return "Unauthorized"; /* RFC2616 Section 10.4.2 */
  case 402:
    return "Payment Required"; /* RFC2616 Section 10.4.3 */
  case 403:
    return "Forbidden"; /* RFC2616 Section 10.4.4 */
  case 404:
    return "Not Found"; /* RFC2616 Section 10.4.5 */
  case 405:
    return "Method Not Allowed"; /* RFC2616 Section 10.4.6 */
  case 406:
    return "Not Acceptable"; /* RFC2616 Section 10.4.7 */
  case 407:
    return "Proxy Authentication Required"; /* RFC2616 Section 10.4.8 */
  case 408:
    return "Request Time-out"; /* RFC2616 Section 10.4.9 */
  case 409:
    return "Conflict"; /* RFC2616 Section 10.4.10 */
  case 410:
    return "Gone"; /* RFC2616 Section 10.4.11 */
  case 411:
    return "Length Required"; /* RFC2616 Section 10.4.12 */
  case 412:
    return "Precondition Failed"; /* RFC2616 Section 10.4.13 */
  case 413:
    return "Request Entity Too Large"; /* RFC2616 Section 10.4.14 */
  case 414:
    return "Request-URI Too Large"; /* RFC2616 Section 10.4.15 */
  case 415:
    return "Unsupported Media Type"; /* RFC2616 Section 10.4.16 */
  case 416:
    return "Requested range not satisfiable"; /* RFC2616 Section 10.4.17
                                               */
  case 417:
    return "Expectation Failed"; /* RFC2616 Section 10.4.18 */

  case 421:
    return "Misdirected Request"; /* RFC7540 Section 9.1.2 */
  case 422:
    return "Unproccessable entity"; /* RFC2518 Section 10.3, RFC4918
                                     * Section 11.2 */
  case 423:
    return "Locked"; /* RFC2518 Section 10.4, RFC4918 Section 11.3 */
  case 424:
    return "Failed Dependency"; /* RFC2518 Section 10.5, RFC4918
                                 * Section 11.4 */

  case 426:
    return "Upgrade Required"; /* RFC 2817 Section 4 */

  case 428:
    return "Precondition Required"; /* RFC 6585, Section 3 */
  case 429:
    return "Too Many Requests"; /* RFC 6585, Section 4 */

  case 431:
    return "Request Header Fields Too Large"; /* RFC 6585, Section 5 */

  case 451:
    return "Unavailable For Legal Reasons"; /* draft-tbray-http-legally-restricted-status-05,
                                             * Section 3 */

    /* RFC2616 Section 10.5 - Server Error 5xx */
  case 500:
    return "Internal Server Error"; /* RFC2616 Section 10.5.1 */
  case 501:
    return "Not Implemented"; /* RFC2616 Section 10.5.2 */
  case 502:
    return "Bad Gateway"; /* RFC2616 Section 10.5.3 */
  case 503:
    return "Service Unavailable"; /* RFC2616 Section 10.5.4 */
  case 504:
    return "Gateway Time-out"; /* RFC2616 Section 10.5.5 */
  case 505:
    return "HTTP Version not supported"; /* RFC2616 Section 10.5.6 */
  case 506:
    return "Variant Also Negotiates"; /* RFC 2295, Section 8.1 */
  case 507:
    return "Insufficient Storage"; /* RFC2518 Section 10.6, RFC4918
                                    * Section 11.5 */
  case 508:
    return "Loop Detected"; /* RFC5842 Section 7.1 */

  case 510:
    return "Not Extended"; /* RFC 2774, Section 7 */
  case 511:
    return "Network Authentication Required"; /* RFC 6585, Section 6 */

    /* Other status codes, not shown in the IANA HTTP status code
     * assignment.
     * E.g., "de facto" standards due to common use, ... */
  case 418:
    return "I am a teapot"; /* RFC2324 Section 2.3.2 */
  case 419:
    return "Authentication Timeout"; /* common use */
  case 420:
    return "Enhance Your Calm"; /* common use */
  case 440:
    return "Login Timeout"; /* common use */
  case 509:
    return "Bandwidth Limit Exceeded"; /* common use */

  default:
    /* This error code is unknown. This should not happen. */
    if (conn) {
      mg_cry_internal(conn,
                      "Unknown HTTP response code: %u",
                      response_code);
    }

    /* Return at least a category according to RFC 2616 Section 10. */
    if (response_code >= 100 && response_code < 200) {
      /* Unknown informational status code */
      return "Information";
    }
    if (response_code >= 200 && response_code < 300) {
      /* Unknown success code */
      return "Success";
    }
    if (response_code >= 300 && response_code < 400) {
      /* Unknown redirection code */
      return "Redirection";
    }
    if (response_code >= 400 && response_code < 500) {
      /* Unknown request error code */
      return "Client Error";
    }
    if (response_code >= 500 && response_code < 600) {
      /* Unknown server error code */
      return "Server Error";
    }

    /* Response code not even within reasonable range */
    return "";
  }
}


static int
mg_send_http_error_impl(struct mg_connection *conn,
                        int status,
                        const char *fmt,
                        va_list args)
{
  char errmsg_buf[MG_BUF_LEN];
  va_list ap;
  int has_body;

#if !defined(NO_FILESYSTEMS)
  char path_buf[UTF8_PATH_MAX];
  int len, i, page_handler_found, scope, truncated;
  const char *error_handler = NULL;
  struct mg_file error_page_file = STRUCT_FILE_INITIALIZER;
  const char *error_page_file_ext, *tstr;
#endif /* NO_FILESYSTEMS */
  int handled_by_callback = 0;

  if ((conn == NULL) || (fmt == NULL)) {
    return -2;
  }

  /* Set status (for log) */
  conn->status_code = status;

  /* Errors 1xx, 204 and 304 MUST NOT send a body */
  has_body = ((status > 199) && (status != 204) && (status != 304));

  /* Prepare message in buf, if required */
  if (has_body
      || (!conn->in_error_handler
          && (conn->phys_ctx->callbacks.http_error != NULL))) {
    /* Store error message in errmsg_buf */
    va_copy(ap, args);
    mg_vsnprintf(conn, NULL, errmsg_buf, sizeof(errmsg_buf), fmt, ap);
    va_end(ap);
    /* In a debug build, print all html errors */
    DEBUG_TRACE("Error %i - [%s]", status, errmsg_buf);
  }

  /* If there is a http_error callback, call it.
   * But don't do it recursively, if callback calls mg_send_http_error again.
   */
  if (!conn->in_error_handler
      && (conn->phys_ctx->callbacks.http_error != NULL)) {
    /* Mark in_error_handler to avoid recursion and call user callback. */
    conn->in_error_handler = 1;
    handled_by_callback =
        (conn->phys_ctx->callbacks.http_error(conn, status, errmsg_buf)
         == 0);
    conn->in_error_handler = 0;
  }

  if (!handled_by_callback) {
    /* Check for recursion */
    if (conn->in_error_handler) {
      DEBUG_TRACE(
          "Recursion when handling error %u - fall back to default",
          status);
#if !defined(NO_FILESYSTEMS)
    } else {
      /* Send user defined error pages, if defined */
      error_handler = conn->dom_ctx->config[ERROR_PAGES];
      error_page_file_ext = conn->dom_ctx->config[INDEX_FILES];
      page_handler_found = 0;

      if (error_handler != NULL) {
        for (scope = 1; (scope <= 3) && !page_handler_found; scope++) {
          switch (scope) {
          case 1: /* Handler for specific error, e.g. 404 error */
            mg_snprintf(conn,
                        &truncated,
                        path_buf,
                        sizeof(path_buf) - 32,
                        "%serror%03u.",
                        error_handler,
                        status);
            break;
          case 2: /* Handler for error group, e.g., 5xx error
                   * handler
                   * for all server errors (500-599) */
            mg_snprintf(conn,
                        &truncated,
                        path_buf,
                        sizeof(path_buf) - 32,
                        "%serror%01uxx.",
                        error_handler,
                        status / 100);
            break;
          default: /* Handler for all errors */
            mg_snprintf(conn,
                        &truncated,
                        path_buf,
                        sizeof(path_buf) - 32,
                        "%serror.",
                        error_handler);
            break;
          }

          /* String truncation in buf may only occur if
           * error_handler is too long. This string is
           * from the config, not from a client. */
          (void)truncated;

          /* The following code is redundant, but it should avoid
           * false positives in static source code analyzers and
           * vulnerability scanners.
           */
          path_buf[sizeof(path_buf) - 32] = 0;
          len = (int)strlen(path_buf);
          if (len > (int)sizeof(path_buf) - 32) {
            len = (int)sizeof(path_buf) - 32;
          }

          /* Start with the file extension from the configuration. */
          tstr = strchr(error_page_file_ext, '.');

          while (tstr) {
            for (i = 1;
                 (i < 32) && (tstr[i] != 0) && (tstr[i] != ',');
                 i++) {
              /* buffer overrun is not possible here, since
               * (i < 32) && (len < sizeof(path_buf) - 32)
               * ==> (i + len) < sizeof(path_buf) */
              path_buf[len + i - 1] = tstr[i];
            }
            /* buffer overrun is not possible here, since
             * (i <= 32) && (len < sizeof(path_buf) - 32)
             * ==> (i + len) <= sizeof(path_buf) */
            path_buf[len + i - 1] = 0;

            if (mg_stat(conn, path_buf, &error_page_file.stat)) {
              DEBUG_TRACE("Check error page %s - found",
                          path_buf);
              page_handler_found = 1;
              break;
            }
            DEBUG_TRACE("Check error page %s - not found",
                        path_buf);

            /* Continue with the next file extension from the
             * configuration (if there is a next one). */
            tstr = strchr(tstr + i, '.');
          }
        }
      }

      if (page_handler_found) {
        conn->in_error_handler = 1;
        handle_file_based_request(conn, path_buf, &error_page_file);
        conn->in_error_handler = 0;
        return 0;
      }
#endif /* NO_FILESYSTEMS */
    }

    /* No custom error page. Send default error page. */
    conn->must_close = 1;
    mg_response_header_start(conn, status);
    send_no_cache_header(conn);
    send_additional_header(conn);
    send_cors_header(conn);
    if (has_body) {
      mg_response_header_add(conn,
                             "Content-Type",
                             "text/plain; charset=utf-8",
                             -1);
    }
    mg_response_header_send(conn);

    /* HTTP responses 1xx, 204 and 304 MUST NOT send a body */
    if (has_body) {
      /* For other errors, send a generic error message. */
      const char *status_text = mg_get_response_code_text(conn, status);
      mg_printf(conn, "Error %d: %s\n", status, status_text);
      mg_write(conn, errmsg_buf, strlen(errmsg_buf));

    } else {
      /* No body allowed. Close the connection. */
      DEBUG_TRACE("Error %i", status);
    }
  }
  return 0;
}


CIVETWEB_API int
mg_send_http_error(struct mg_connection *conn, int status, const char *fmt, ...)
{
  va_list ap;
  int ret;

  va_start(ap, fmt);
  ret = mg_send_http_error_impl(conn, status, fmt, ap);
  va_end(ap);

  return ret;
}


CIVETWEB_API int
mg_send_http_ok(struct mg_connection *conn,
                const char *mime_type,
                long long content_length)
{
  if ((mime_type == NULL) || (*mime_type == 0)) {
    /* No content type defined: default to text/html */
    mime_type = "text/html";
  }

  mg_response_header_start(conn, 200);
  send_no_cache_header(conn);
  send_additional_header(conn);
  send_cors_header(conn);
  mg_response_header_add(conn, "Content-Type", mime_type, -1);
  if (content_length < 0) {
    /* Size not known. Use chunked encoding (HTTP/1.x) */
    if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
      /* Only HTTP/1.x defines "chunked" encoding, HTTP/2 does not*/
      mg_response_header_add(conn, "Transfer-Encoding", "chunked", -1);
    }
  } else {
    char len[32];
    int trunc = 0;
    mg_snprintf(conn,
                &trunc,
                len,
                sizeof(len),
                "%" UINT64_FMT,
                (uint64_t)content_length);
    if (!trunc) {
      /* Since 32 bytes is enough to hold any 64 bit decimal number,
       * !trunc is always true */
      mg_response_header_add(conn, "Content-Length", len, -1);
    }
  }
  mg_response_header_send(conn);

  return 0;
}


CIVETWEB_API int
mg_send_http_redirect(struct mg_connection *conn,
                      const char *target_url,
                      int redirect_code)
{
  /* Send a 30x redirect response.
   *
   * Redirect types (status codes):
   *
   * Status | Perm/Temp | Method              | Version
   *   301  | permanent | POST->GET undefined | HTTP/1.0
   *   302  | temporary | POST->GET undefined | HTTP/1.0
   *   303  | temporary | always use GET      | HTTP/1.1
   *   307  | temporary | always keep method  | HTTP/1.1
   *   308  | permanent | always keep method  | HTTP/1.1
   */

#if defined(MG_SEND_REDIRECT_BODY)
  char redirect_body[MG_BUF_LEN];
  size_t content_len = 0;
  char content_len_text[32];
#endif

  /* In case redirect_code=0, use 307. */
  if (redirect_code == 0) {
    redirect_code = 307;
  }

  /* In case redirect_code is none of the above, return error. */
  if ((redirect_code != 301) && (redirect_code != 302)
      && (redirect_code != 303) && (redirect_code != 307)
      && (redirect_code != 308)) {
    /* Parameter error */
    return -2;
  }

  /* If target_url is not defined, redirect to "/". */
  if ((target_url == NULL) || (*target_url == 0)) {
    target_url = "/";
  }

#if defined(MG_SEND_REDIRECT_BODY)
  /* TODO: condition name? */

  /* Prepare a response body with a hyperlink.
   *
   * According to RFC2616 (and RFC1945 before):
   * Unless the request method was HEAD, the entity of the
   * response SHOULD contain a short hypertext note with a hyperlink to
   * the new URI(s).
   *
   * However, this response body is not useful in M2M communication.
   * Probably the original reason in the RFC was, clients not supporting
   * a 30x HTTP redirect could still show the HTML page and let the user
   * press the link. Since current browsers support 30x HTTP, the additional
   * HTML body does not seem to make sense anymore.
   *
   * The new RFC7231 (Section 6.4) does no longer recommend it ("SHOULD"),
   * but it only notes:
   * The server's response payload usually contains a short
   * hypertext note with a hyperlink to the new URI(s).
   *
   * Deactivated by default. If you need the 30x body, set the define.
   */
  mg_snprintf(
      conn,
      NULL /* ignore truncation */,
      redirect_body,
      sizeof(redirect_body),
      "<html><head>%s</head><body><a href=\"%s\">%s</a></body></html>",
      redirect_text,
      target_url,
      target_url);
  content_len = strlen(reply);
  sprintf(content_len_text, "%lu", (unsigned long)content_len);
#endif

  /* Send all required headers */
  mg_response_header_start(conn, redirect_code);
  mg_response_header_add(conn, "Location", target_url, -1);
  if ((redirect_code == 301) || (redirect_code == 308)) {
    /* Permanent redirect */
    send_static_cache_header(conn);
  } else {
    /* Temporary redirect */
    send_no_cache_header(conn);
  }
  send_additional_header(conn);
  send_cors_header(conn);
#if defined(MG_SEND_REDIRECT_BODY)
  mg_response_header_add(conn, "Content-Type", "text/html", -1);
  mg_response_header_add(conn, "Content-Length", content_len_text, -1);
#else
  mg_response_header_add(conn, "Content-Length", "0", 1);
#endif
  mg_response_header_send(conn);

#if defined(MG_SEND_REDIRECT_BODY)
  /* Send response body */
  /* ... unless it is a HEAD request */
  if (0 != strcmp(conn->request_info.request_method, "HEAD")) {
    ret = mg_write(conn, redirect_body, content_len);
  }
#endif

  return 1;
}


#if defined(_WIN32)
/* Create substitutes for POSIX functions in Win32. */

#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


static int
pthread_mutex_init(pthread_mutex_t *mutex, void *unused)
{
  (void)unused;
  /* Always initialize as PTHREAD_MUTEX_RECURSIVE */
  InitializeCriticalSection(&mutex->sec);
  return 0;
}


static int
pthread_mutex_destroy(pthread_mutex_t *mutex)
{
  DeleteCriticalSection(&mutex->sec);
  return 0;
}


static int
pthread_mutex_lock(pthread_mutex_t *mutex)
{
  EnterCriticalSection(&mutex->sec);
  return 0;
}


static int
pthread_mutex_unlock(pthread_mutex_t *mutex)
{
  LeaveCriticalSection(&mutex->sec);
  return 0;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_init(pthread_cond_t *cv, const void *unused)
{
  (void)unused;
  (void)pthread_mutex_init(&cv->threadIdSec, &pthread_mutex_attr);
  cv->waiting_thread = NULL;
  return 0;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_timedwait(pthread_cond_t *cv,
                       pthread_mutex_t *mutex,
                       FUNCTION_MAY_BE_UNUSED const struct timespec *abstime)
{
  struct mg_workerTLS **ptls,
      *tls = (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
  int ok;
  uint64_t nsnow, nswaitabs;
  int64_t nswaitrel;
  DWORD mswaitrel;

  pthread_mutex_lock(&cv->threadIdSec);
  /* Add this thread to cv's waiting list */
  ptls = &cv->waiting_thread;
  for (; *ptls != NULL; ptls = &(*ptls)->next_waiting_thread)
    ;
  tls->next_waiting_thread = NULL;
  *ptls = tls;
  pthread_mutex_unlock(&cv->threadIdSec);

  if (abstime) {
    nsnow = mg_get_current_time_ns();
    nswaitabs =
        (((uint64_t)abstime->tv_sec) * 1000000000) + abstime->tv_nsec;
    nswaitrel = nswaitabs - nsnow;
    if (nswaitrel < 0) {
      nswaitrel = 0;
    }
    mswaitrel = (DWORD)(nswaitrel / 1000000);
  } else {
    mswaitrel = (DWORD)INFINITE;
  }

  pthread_mutex_unlock(mutex);
  ok = (WAIT_OBJECT_0
        == WaitForSingleObject(tls->pthread_cond_helper_mutex, mswaitrel));
  if (!ok) {
    ok = 1;
    pthread_mutex_lock(&cv->threadIdSec);
    ptls = &cv->waiting_thread;
    for (; *ptls != NULL; ptls = &(*ptls)->next_waiting_thread) {
      if (*ptls == tls) {
        *ptls = tls->next_waiting_thread;
        ok = 0;
        break;
      }
    }
    pthread_mutex_unlock(&cv->threadIdSec);
    if (ok) {
      WaitForSingleObject(tls->pthread_cond_helper_mutex,
                          (DWORD)INFINITE);
    }
  }
  /* This thread has been removed from cv's waiting list */
  pthread_mutex_lock(mutex);

  return ok ? 0 : -1;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex)
{
  return pthread_cond_timedwait(cv, mutex, NULL);
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_signal(pthread_cond_t *cv)
{
  HANDLE wkup = NULL;
  BOOL ok = FALSE;

  pthread_mutex_lock(&cv->threadIdSec);
  if (cv->waiting_thread) {
    wkup = cv->waiting_thread->pthread_cond_helper_mutex;
    cv->waiting_thread = cv->waiting_thread->next_waiting_thread;

    ok = SetEvent(wkup);
    DEBUG_ASSERT(ok);
  }
  pthread_mutex_unlock(&cv->threadIdSec);

  return ok ? 0 : 1;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_broadcast(pthread_cond_t *cv)
{
  pthread_mutex_lock(&cv->threadIdSec);
  while (cv->waiting_thread) {
    pthread_cond_signal(cv);
  }
  pthread_mutex_unlock(&cv->threadIdSec);

  return 0;
}


FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_destroy(pthread_cond_t *cv)
{
  pthread_mutex_lock(&cv->threadIdSec);
  DEBUG_ASSERT(cv->waiting_thread == NULL);
  pthread_mutex_unlock(&cv->threadIdSec);
  pthread_mutex_destroy(&cv->threadIdSec);

  return 0;
}


#if defined(ALTERNATIVE_QUEUE)
FUNCTION_MAY_BE_UNUSED
static void *
event_create(void)
{
  return (void *)CreateEvent(NULL, FALSE, FALSE, NULL);
}


FUNCTION_MAY_BE_UNUSED
static int
event_wait(void *eventhdl)
{
  int res = WaitForSingleObject((HANDLE)eventhdl, (DWORD)INFINITE);
  return (res == WAIT_OBJECT_0);
}


FUNCTION_MAY_BE_UNUSED
static int
event_signal(void *eventhdl)
{
  return (int)SetEvent((HANDLE)eventhdl);
}


FUNCTION_MAY_BE_UNUSED
static void
event_destroy(void *eventhdl)
{
  CloseHandle((HANDLE)eventhdl);
}
#endif


#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif


/* For Windows, change all slashes to backslashes in path names. */
static void
change_slashes_to_backslashes(char *path)
{
  int i;

  for (i = 0; path[i] != '\0'; i++) {
    if (path[i] == '/') {
      path[i] = '\\';
    }

    /* remove double backslash (check i > 0 to preserve UNC paths,
     * like \\server\file.txt) */
    if ((i > 0) && (path[i] == '\\')) {
      while ((path[i + 1] == '\\') || (path[i + 1] == '/')) {
        (void)memmove(path + i + 1, path + i + 2, strlen(path + i + 1));
      }
    }
  }
}


static int
mg_wcscasecmp(const wchar_t *s1, const wchar_t *s2)
{
  int diff;

  do {
    diff = ((*s1 >= L'A') && (*s1 <= L'Z') ? (*s1 - L'A' + L'a') : *s1)
           - ((*s2 >= L'A') && (*s2 <= L'Z') ? (*s2 - L'A' + L'a') : *s2);
    s1++;
    s2++;
  } while ((diff == 0) && (s1[-1] != L'\0'));

  return diff;
}


/* Encode 'path' which is assumed UTF-8 string, into UNICODE string.
 * wbuf and wbuf_len is a target buffer and its length. */
static void
path_to_unicode(const struct mg_connection *conn,
                const char *path,
                wchar_t *wbuf,
                size_t wbuf_len)
{
  char buf[UTF8_PATH_MAX], buf2[UTF8_PATH_MAX];
  wchar_t wbuf2[UTF16_PATH_MAX + 1];
  DWORD long_len, err;
  int (*fcompare)(const wchar_t *, const wchar_t *) = mg_wcscasecmp;

  mg_strlcpy(buf, path, sizeof(buf));
  change_slashes_to_backslashes(buf);

  /* Convert to Unicode and back. If doubly-converted string does not
   * match the original, something is fishy, reject. */
  memset(wbuf, 0, wbuf_len * sizeof(wchar_t));
  MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int)wbuf_len);
  WideCharToMultiByte(
      CP_UTF8, 0, wbuf, (int)wbuf_len, buf2, sizeof(buf2), NULL, NULL);
  if (strcmp(buf, buf2) != 0) {
    wbuf[0] = L'\0';
  }

  /* Windows file systems are not case sensitive, but you can still use
   * uppercase and lowercase letters (on all modern file systems).
   * The server can check if the URI uses the same upper/lowercase
   * letters an the file system, effectively making Windows servers
   * case sensitive (like Linux servers are). It is still not possible
   * to use two files with the same name in different cases on Windows
   * (like /a and /A) - this would be possible in Linux.
   * As a default, Windows is not case sensitive, but the case sensitive
   * file name check can be activated by an additional configuration. */
  if (conn) {
    if (conn->dom_ctx->config[CASE_SENSITIVE_FILES]
        && !mg_strcasecmp(conn->dom_ctx->config[CASE_SENSITIVE_FILES],
                          "yes")) {
      /* Use case sensitive compare function */
      fcompare = wcscmp;
    }
  }
  (void)conn; /* conn is currently unused */

  /* Only accept a full file path, not a Windows short (8.3) path. */
  memset(wbuf2, 0, ARRAY_SIZE(wbuf2) * sizeof(wchar_t));
  long_len = GetLongPathNameW(wbuf, wbuf2, ARRAY_SIZE(wbuf2) - 1);
  if (long_len == 0) {
    err = GetLastError();
    if (err == ERROR_FILE_NOT_FOUND) {
      /* File does not exist. This is not always a problem here. */
      return;
    }
  }
  if ((long_len >= ARRAY_SIZE(wbuf2)) || (fcompare(wbuf, wbuf2) != 0)) {
    /* Short name is used. */
    wbuf[0] = L'\0';
  }
}


#if !defined(NO_FILESYSTEMS)
/* Get file information, return 1 if file exists, 0 if not */
static int
mg_stat(const struct mg_connection *conn,
        const char *path,
        struct mg_file_stat *filep)
{
  wchar_t wbuf[UTF16_PATH_MAX];
  WIN32_FILE_ATTRIBUTE_DATA info;
  time_t creation_time;
  size_t len;

  if (!filep) {
    return 0;
  }
  memset(filep, 0, sizeof(*filep));

  if (mg_path_suspicious(conn, path)) {
    return 0;
  }

  path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
  /* Windows happily opens files with some garbage at the end of file name.
   * For example, fopen("a.cgi    ", "r") on Windows successfully opens
   * "a.cgi", despite one would expect an error back. */
  len = strlen(path);
  if ((len > 0) && (path[len - 1] != ' ') && (path[len - 1] != '.')
      && (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0)) {
    filep->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
    filep->last_modified =
        SYS2UNIX_TIME(info.ftLastWriteTime.dwLowDateTime,
                      info.ftLastWriteTime.dwHighDateTime);

    /* On Windows, the file creation time can be higher than the
     * modification time, e.g. when a file is copied.
     * Since the Last-Modified timestamp is used for caching
     * it should be based on the most recent timestamp. */
    creation_time = SYS2UNIX_TIME(info.ftCreationTime.dwLowDateTime,
                                  info.ftCreationTime.dwHighDateTime);
    if (creation_time > filep->last_modified) {
      filep->last_modified = creation_time;
    }

    filep->is_directory = info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
    return 1;
  }

  return 0;
}
#endif


static int
mg_remove(const struct mg_connection *conn, const char *path)
{
  wchar_t wbuf[UTF16_PATH_MAX];
  path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
  return DeleteFileW(wbuf) ? 0 : -1;
}


static int
mg_mkdir(const struct mg_connection *conn, const char *path, int mode)
{
  wchar_t wbuf[UTF16_PATH_MAX];
  (void)mode;
  path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
  return CreateDirectoryW(wbuf, NULL) ? 0 : -1;
}


/* Create substitutes for POSIX functions in Win32. */

#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


/* Implementation of POSIX opendir/closedir/readdir for Windows. */
FUNCTION_MAY_BE_UNUSED
static DIR *
mg_opendir(const struct mg_connection *conn, const char *name)
{
  DIR *dir = NULL;
  wchar_t wpath[UTF16_PATH_MAX];
  DWORD attrs;

  if (name == NULL) {
    SetLastError(ERROR_BAD_ARGUMENTS);
  } else if ((dir = (DIR *)mg_malloc(sizeof(*dir))) == NULL) {
    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
  } else {
    path_to_unicode(conn, name, wpath, ARRAY_SIZE(wpath));
    attrs = GetFileAttributesW(wpath);
    if ((wcslen(wpath) + 2 < ARRAY_SIZE(wpath)) && (attrs != 0xFFFFFFFF)
        && ((attrs & FILE_ATTRIBUTE_DIRECTORY) != 0)) {
      (void)wcscat(wpath, L"\\*");
      dir->handle = FindFirstFileW(wpath, &dir->info);
      dir->result.d_name[0] = '\0';
    } else {
      mg_free(dir);
      dir = NULL;
    }
  }

  return dir;
}


FUNCTION_MAY_BE_UNUSED
static int
mg_closedir(DIR *dir)
{
  int result = 0;

  if (dir != NULL) {
    if (dir->handle != INVALID_HANDLE_VALUE)
      result = FindClose(dir->handle) ? 0 : -1;

    mg_free(dir);
  } else {
    result = -1;
    SetLastError(ERROR_BAD_ARGUMENTS);
  }

  return result;
}


FUNCTION_MAY_BE_UNUSED
static struct dirent *
mg_readdir(DIR *dir)
{
  struct dirent *result = 0;

  if (dir) {
    if (dir->handle != INVALID_HANDLE_VALUE) {
      result = &dir->result;
      (void)WideCharToMultiByte(CP_UTF8,
                                0,
                                dir->info.cFileName,
                                -1,
                                result->d_name,
                                sizeof(result->d_name),
                                NULL,
                                NULL);

      if (!FindNextFileW(dir->handle, &dir->info)) {
        (void)FindClose(dir->handle);
        dir->handle = INVALID_HANDLE_VALUE;
      }

    } else {
      SetLastError(ERROR_FILE_NOT_FOUND);
    }
  } else {
    SetLastError(ERROR_BAD_ARGUMENTS);
  }

  return result;
}


#if !defined(HAVE_POLL)
#undef POLLIN
#undef POLLPRI
#undef POLLOUT
#undef POLLERR
#define POLLIN (1)  /* Data ready - read will not block. */
#define POLLPRI (2) /* Priority data ready. */
#define POLLOUT (4) /* Send queue not full - write will not block. */
#define POLLERR (8) /* Error event */

FUNCTION_MAY_BE_UNUSED
static int
poll(struct mg_pollfd *pfd, unsigned int n, int milliseconds)
{
  struct timeval tv;
  fd_set rset;
  fd_set wset;
  fd_set eset;
  unsigned int i;
  int result;
  SOCKET maxfd = 0;

  memset(&tv, 0, sizeof(tv));
  tv.tv_sec = milliseconds / 1000;
  tv.tv_usec = (milliseconds % 1000) * 1000;
  FD_ZERO(&rset);
  FD_ZERO(&wset);
  FD_ZERO(&eset);

  for (i = 0; i < n; i++) {
    if (pfd[i].events & (POLLIN | POLLOUT | POLLERR)) {
      if (pfd[i].events & POLLIN) {
        FD_SET(pfd[i].fd, &rset);
      }
      if (pfd[i].events & POLLOUT) {
        FD_SET(pfd[i].fd, &wset);
      }
      /* Check for errors for any FD in the set */
      FD_SET(pfd[i].fd, &eset);
    }
    pfd[i].revents = 0;

    if (pfd[i].fd > maxfd) {
      maxfd = pfd[i].fd;
    }
  }

  if ((result = select((int)maxfd + 1, &rset, &wset, &eset, &tv)) > 0) {
    for (i = 0; i < n; i++) {
      if (FD_ISSET(pfd[i].fd, &rset)) {
        pfd[i].revents |= POLLIN;
      }
      if (FD_ISSET(pfd[i].fd, &wset)) {
        pfd[i].revents |= POLLOUT;
      }
      if (FD_ISSET(pfd[i].fd, &eset)) {
        pfd[i].revents |= POLLERR;
      }
    }
  }

  /* We should subtract the time used in select from remaining
   * "milliseconds", in particular if called from mg_poll with a
   * timeout quantum.
   * Unfortunately, the remaining time is not stored in "tv" in all
   * implementations, so the result in "tv" must be considered undefined.
   * See http://man7.org/linux/man-pages/man2/select.2.html */

  return result;
}
#endif /* HAVE_POLL */


#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif


static void
set_close_on_exec(SOCKET sock,
                  const struct mg_connection *conn /* may be null */,
                  struct mg_context *ctx /* may be null */)
{
  (void)conn; /* Unused. */
  (void)ctx;

  (void)SetHandleInformation((HANDLE)(intptr_t)sock, HANDLE_FLAG_INHERIT, 0);
}


CIVETWEB_API int
mg_start_thread(mg_thread_func_t f, void *p)
{
#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
  /* Compile-time option to control stack size, e.g.
   * -DUSE_STACK_SIZE=16384
   */
  return ((_beginthread((void(__cdecl *)(void *))f, USE_STACK_SIZE, p)
           == ((uintptr_t)(-1L)))
              ? -1
              : 0);
#else
  return (
      (_beginthread((void(__cdecl *)(void *))f, 0, p) == ((uintptr_t)(-1L)))
          ? -1
          : 0);
#endif /* defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1) */
}


/* Start a thread storing the thread context. */
static int
mg_start_thread_with_id(unsigned(__stdcall *f)(void *),
                        void *p,
                        pthread_t *threadidptr)
{
  uintptr_t uip;
  HANDLE threadhandle;
  int result = -1;

  uip = _beginthreadex(NULL, 0, f, p, 0, NULL);
  threadhandle = (HANDLE)uip;
  if ((uip != 0) && (threadidptr != NULL)) {
    *threadidptr = threadhandle;
    result = 0;
  }

  return result;
}


/* Wait for a thread to finish. */
static int
mg_join_thread(pthread_t threadid)
{
  int result;
  DWORD dwevent;

  result = -1;
  dwevent = WaitForSingleObject(threadid, (DWORD)INFINITE);
  if (dwevent == WAIT_FAILED) {
    DEBUG_TRACE("WaitForSingleObject() failed, error %d", ERRNO);
  } else {
    if (dwevent == WAIT_OBJECT_0) {
      CloseHandle(threadid);
      result = 0;
    }
  }

  return result;
}

#if !defined(NO_SSL_DL) && !defined(NO_SSL)
/* If SSL is loaded dynamically, dlopen/dlclose is required. */
/* Create substitutes for POSIX functions in Win32. */

#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


FUNCTION_MAY_BE_UNUSED
static HANDLE
dlopen(const char *dll_name, int flags)
{
  wchar_t wbuf[UTF16_PATH_MAX];
  (void)flags;
  path_to_unicode(NULL, dll_name, wbuf, ARRAY_SIZE(wbuf));
  return LoadLibraryW(wbuf);
}


FUNCTION_MAY_BE_UNUSED
static int
dlclose(void *handle)
{
  int result;

  if (FreeLibrary((HMODULE)handle) != 0) {
    result = 0;
  } else {
    result = -1;
  }

  return result;
}


#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif

#endif


#if !defined(NO_CGI)
#define SIGKILL (0)


static int
kill(pid_t pid, int sig_num)
{
  (void)TerminateProcess((HANDLE)pid, (UINT)sig_num);
  (void)CloseHandle((HANDLE)pid);
  return 0;
}


#if !defined(WNOHANG)
#define WNOHANG (1)
#endif


static pid_t
waitpid(pid_t pid, int *status, int flags)
{
  DWORD timeout = INFINITE;
  DWORD waitres;

  (void)status; /* Currently not used by any client here */

  if ((flags | WNOHANG) == WNOHANG) {
    timeout = 0;
  }

  waitres = WaitForSingleObject((HANDLE)pid, timeout);
  if (waitres == WAIT_OBJECT_0) {
    return pid;
  }
  if (waitres == WAIT_TIMEOUT) {
    return 0;
  }
  return (pid_t)-1;
}


static void
trim_trailing_whitespaces(char *s)
{
  char *e = s + strlen(s);
  while ((e > s) && isspace((unsigned char)e[-1])) {
    *(--e) = '\0';
  }
}


static pid_t
spawn_process(struct mg_connection *conn,
              const char *prog,
              char *envblk,
              char *envp[],
              int fdin[2],
              int fdout[2],
              int fderr[2],
              const char *dir,
              unsigned char cgi_config_idx)
{
  HANDLE me;
  char *interp;
  char *interp_arg = 0;
  char full_dir[UTF8_PATH_MAX], cmdline[UTF8_PATH_MAX], buf[UTF8_PATH_MAX];
  int truncated;
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  STARTUPINFOA si;
  PROCESS_INFORMATION pi = {0};

  (void)envp;

  memset(&si, 0, sizeof(si));
  si.cb = sizeof(si);

  si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
  si.wShowWindow = SW_HIDE;

  me = GetCurrentProcess();
  DuplicateHandle(me,
                  (HANDLE)_get_osfhandle(fdin[0]),
                  me,
                  &si.hStdInput,
                  0,
                  TRUE,
                  DUPLICATE_SAME_ACCESS);
  DuplicateHandle(me,
                  (HANDLE)_get_osfhandle(fdout[1]),
                  me,
                  &si.hStdOutput,
                  0,
                  TRUE,
                  DUPLICATE_SAME_ACCESS);
  DuplicateHandle(me,
                  (HANDLE)_get_osfhandle(fderr[1]),
                  me,
                  &si.hStdError,
                  0,
                  TRUE,
                  DUPLICATE_SAME_ACCESS);

  /* Mark handles that should not be inherited. See
   * https://msdn.microsoft.com/en-us/library/windows/desktop/ms682499%28v=vs.85%29.aspx
   */
  SetHandleInformation((HANDLE)_get_osfhandle(fdin[1]),
                       HANDLE_FLAG_INHERIT,
                       0);
  SetHandleInformation((HANDLE)_get_osfhandle(fdout[0]),
                       HANDLE_FLAG_INHERIT,
                       0);
  SetHandleInformation((HANDLE)_get_osfhandle(fderr[0]),
                       HANDLE_FLAG_INHERIT,
                       0);

  /* First check, if there is a CGI interpreter configured for all CGI
   * scripts. */
  interp = conn->dom_ctx->config[CGI_INTERPRETER + cgi_config_idx];
  if (interp != NULL) {
    /* If there is a configured interpreter, check for additional arguments
     */
    interp_arg =
        conn->dom_ctx->config[CGI_INTERPRETER_ARGS + cgi_config_idx];
  } else {
    /* Otherwise, the interpreter must be stated in the first line of the
     * CGI script file, after a #! (shebang) mark. */
    buf[0] = buf[1] = '\0';

    /* Get the full script path */
    mg_snprintf(
        conn, &truncated, cmdline, sizeof(cmdline), "%s/%s", dir, prog);

    if (truncated) {
      pi.hProcess = (pid_t)-1;
      goto spawn_cleanup;
    }

    /* Open the script file, to read the first line */
    if (mg_fopen(conn, cmdline, MG_FOPEN_MODE_READ, &file)) {

      /* Read the first line of the script into the buffer */
      mg_fgets(buf, sizeof(buf), &file);
      (void)mg_fclose(&file.access); /* ignore error on read only file */
      buf[sizeof(buf) - 1] = '\0';
    }

    if ((buf[0] == '#') && (buf[1] == '!')) {
      trim_trailing_whitespaces(buf + 2);
    } else {
      buf[2] = '\0';
    }
    interp = buf + 2;
  }

  GetFullPathNameA(dir, sizeof(full_dir), full_dir, NULL);

  if (interp[0] != '\0') {
    /* This is an interpreted script file. We must call the interpreter. */
    if ((interp_arg != 0) && (interp_arg[0] != 0)) {
      mg_snprintf(conn,
                  &truncated,
                  cmdline,
                  sizeof(cmdline),
                  "\"%s\" %s \"%s\\%s\"",
                  interp,
                  interp_arg,
                  full_dir,
                  prog);
    } else {
      mg_snprintf(conn,
                  &truncated,
                  cmdline,
                  sizeof(cmdline),
                  "\"%s\" \"%s\\%s\"",
                  interp,
                  full_dir,
                  prog);
    }
  } else {
    /* This is (probably) a compiled program. We call it directly. */
    mg_snprintf(conn,
                &truncated,
                cmdline,
                sizeof(cmdline),
                "\"%s\\%s\"",
                full_dir,
                prog);
  }

  if (truncated) {
    pi.hProcess = (pid_t)-1;
    goto spawn_cleanup;
  }

  DEBUG_TRACE("Running [%s]", cmdline);
  if (CreateProcessA(NULL,
                     cmdline,
                     NULL,
                     NULL,
                     TRUE,
                     CREATE_NEW_PROCESS_GROUP,
                     envblk,
                     NULL,
                     &si,
                     &pi)
      == 0) {
    mg_cry_internal(
        conn, "%s: CreateProcess(%s): %ld", __func__, cmdline, (long)ERRNO);
    pi.hProcess = (pid_t)-1;
    /* goto spawn_cleanup; */
  }

spawn_cleanup:
  (void)CloseHandle(si.hStdOutput);
  (void)CloseHandle(si.hStdError);
  (void)CloseHandle(si.hStdInput);
  if (pi.hThread != NULL) {
    (void)CloseHandle(pi.hThread);
  }

  return (pid_t)pi.hProcess;
}
#endif /* !NO_CGI */


static int
set_blocking_mode(SOCKET sock)
{
  unsigned long non_blocking = 0;
  return ioctlsocket(sock, (long)FIONBIO, &non_blocking);
}


static int
set_non_blocking_mode(SOCKET sock)
{
  unsigned long non_blocking = 1;
  return ioctlsocket(sock, (long)FIONBIO, &non_blocking);
}


#else


#if !defined(NO_FILESYSTEMS)
static int
mg_stat(const struct mg_connection *conn,
        const char *path,
        struct mg_file_stat *filep)
{
  struct stat st;
  if (!filep) {
    return 0;
  }
  memset(filep, 0, sizeof(*filep));

  if (mg_path_suspicious(conn, path)) {
    return 0;
  }

  if (0 == stat(path, &st)) {
    filep->size = (uint64_t)(st.st_size);
    filep->last_modified = st.st_mtime;
    filep->is_directory = S_ISDIR(st.st_mode);
    return 1;
  }

  return 0;
}
#endif /* NO_FILESYSTEMS */


static void
set_close_on_exec(int fd,
                  const struct mg_connection *conn /* may be null */,
                  struct mg_context *ctx /* may be null */)
{
#if defined(__ZEPHYR__)
  (void)fd;
  (void)conn;
  (void)ctx;
#else
  if (fcntl(fd, F_SETFD, FD_CLOEXEC) != 0) {
    if (conn || ctx) {
      struct mg_connection fc;
      mg_cry_internal((conn ? conn : fake_connection(&fc, ctx)),
                      "%s: fcntl(F_SETFD FD_CLOEXEC) failed: %s",
                      __func__,
                      strerror(ERRNO));
    }
  }
#endif
}


CIVETWEB_API int
mg_start_thread(mg_thread_func_t func, void *param)
{
  pthread_t thread_id;
  pthread_attr_t attr;
  int result;

  (void)pthread_attr_init(&attr);
  (void)pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

#if defined(__ZEPHYR__)
  pthread_attr_setstack(&attr, &civetweb_main_stack, ZEPHYR_STACK_SIZE);
#elif defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
  /* Compile-time option to control stack size,
   * e.g. -DUSE_STACK_SIZE=16384 */
  (void)pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
#endif /* defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1) */

  result = pthread_create(&thread_id, &attr, func, param);
  pthread_attr_destroy(&attr);

  return result;
}


/* Start a thread storing the thread context. */
static int
mg_start_thread_with_id(mg_thread_func_t func,
                        void *param,
                        pthread_t *threadidptr)
{
  pthread_t thread_id;
  pthread_attr_t attr;
  int result;

  (void)pthread_attr_init(&attr);

#if defined(__ZEPHYR__)
  pthread_attr_setstack(&attr,
                        &civetweb_worker_stacks[zephyr_worker_stack_index++],
                        ZEPHYR_STACK_SIZE);
#elif defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
  /* Compile-time option to control stack size,
   * e.g. -DUSE_STACK_SIZE=16384 */
  (void)pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
#endif /* defined(USE_STACK_SIZE) && USE_STACK_SIZE > 1 */

  result = pthread_create(&thread_id, &attr, func, param);
  pthread_attr_destroy(&attr);
  if ((result == 0) && (threadidptr != NULL)) {
    *threadidptr = thread_id;
  }
  return result;
}


/* Wait for a thread to finish. */
static int
mg_join_thread(pthread_t threadid)
{
  int result;

  result = pthread_join(threadid, NULL);
  return result;
}


#if !defined(NO_CGI)
static pid_t
spawn_process(struct mg_connection *conn,
              const char *prog,
              char *envblk,
              char *envp[],
              int fdin[2],
              int fdout[2],
              int fderr[2],
              const char *dir,
              unsigned char cgi_config_idx)
{
  pid_t pid;
  const char *interp;

  (void)envblk;

  if ((pid = fork()) == -1) {
    /* Parent */
    mg_cry_internal(conn, "%s: fork(): %s", __func__, strerror(ERRNO));
  } else if (pid != 0) {
    /* Make sure children close parent-side descriptors.
     * The caller will close the child-side immediately. */
    set_close_on_exec(fdin[1], conn, NULL);  /* stdin write */
    set_close_on_exec(fdout[0], conn, NULL); /* stdout read */
    set_close_on_exec(fderr[0], conn, NULL); /* stderr read */
  } else {
    /* Child */
    if (chdir(dir) != 0) {
      mg_cry_internal(
          conn, "%s: chdir(%s): %s", __func__, dir, strerror(ERRNO));
    } else if (dup2(fdin[0], 0) == -1) {
      mg_cry_internal(conn,
                      "%s: dup2(%d, 0): %s",
                      __func__,
                      fdin[0],
                      strerror(ERRNO));
    } else if (dup2(fdout[1], 1) == -1) {
      mg_cry_internal(conn,
                      "%s: dup2(%d, 1): %s",
                      __func__,
                      fdout[1],
                      strerror(ERRNO));
    } else if (dup2(fderr[1], 2) == -1) {
      mg_cry_internal(conn,
                      "%s: dup2(%d, 2): %s",
                      __func__,
                      fderr[1],
                      strerror(ERRNO));
    } else {
      struct sigaction sa;

      /* Keep stderr and stdout in two different pipes.
       * Stdout will be sent back to the client,
       * stderr should go into a server error log. */
      (void)close(fdin[0]);
      (void)close(fdout[1]);
      (void)close(fderr[1]);

      /* Close write end fdin and read end fdout and fderr */
      (void)close(fdin[1]);
      (void)close(fdout[0]);
      (void)close(fderr[0]);

      /* After exec, all signal handlers are restored to their default
       * values, with one exception of SIGCHLD. According to
       * POSIX.1-2001 and Linux's implementation, SIGCHLD's handler
       * will leave unchanged after exec if it was set to be ignored.
       * Restore it to default action. */
      memset(&sa, 0, sizeof(sa));
      sa.sa_handler = SIG_DFL;
      sigaction(SIGCHLD, &sa, NULL);

      interp = conn->dom_ctx->config[CGI_INTERPRETER + cgi_config_idx];
      if (interp == NULL) {
        /* no interpreter configured, call the program directly */
        (void)execle(prog, prog, NULL, envp);
        mg_cry_internal(conn,
                        "%s: execle(%s): %s",
                        __func__,
                        prog,
                        strerror(ERRNO));
      } else {
        /* call the configured interpreter */
        const char *interp_args =
            conn->dom_ctx
                ->config[CGI_INTERPRETER_ARGS + cgi_config_idx];

        if ((interp_args != NULL) && (interp_args[0] != 0)) {
          (void)execle(interp, interp, interp_args, prog, NULL, envp);
        } else {
          (void)execle(interp, interp, prog, NULL, envp);
        }
        mg_cry_internal(conn,
                        "%s: execle(%s %s): %s",
                        __func__,
                        interp,
                        prog,
                        strerror(ERRNO));
      }
    }
    exit(EXIT_FAILURE);
  }

  return pid;
}
#endif /* !NO_CGI */


static int
set_non_blocking_mode(SOCKET sock)
{
  int flags = fcntl(sock, F_GETFL, 0);
  if (flags < 0) {
    return -1;
  }

  if (fcntl(sock, F_SETFL, (flags | O_NONBLOCK)) < 0) {
    return -1;
  }
  return 0;
}

static int
set_blocking_mode(SOCKET sock)
{
  int flags = fcntl(sock, F_GETFL, 0);
  if (flags < 0) {
    return -1;
  }

  if (fcntl(sock, F_SETFL, flags & (~(int)(O_NONBLOCK))) < 0) {
    return -1;
  }
  return 0;
}
#endif /* _WIN32 / else */

/* End of initial operating system specific define block. */


/* Get a random number (independent of C rand function) */
static uint64_t
get_random(void)
{
  static uint64_t lfsr = 0; /* Linear feedback shift register */
  static uint64_t lcg = 0;  /* Linear congruential generator */
  uint64_t now = mg_get_current_time_ns();

  if (lfsr == 0) {
    /* lfsr will be only 0 if has not been initialized,
     * so this code is called only once. */
    lfsr = mg_get_current_time_ns();
    lcg = mg_get_current_time_ns();
  } else {
    /* Get the next step of both random number generators. */
    lfsr = (lfsr >> 1)
           | ((((lfsr >> 0) ^ (lfsr >> 1) ^ (lfsr >> 3) ^ (lfsr >> 4)) & 1)
              << 63);
    lcg = lcg * 6364136223846793005LL + 1442695040888963407LL;
  }

  /* Combining two pseudo-random number generators and a high resolution
   * part
   * of the current server time will make it hard (impossible?) to guess
   * the
   * next number. */
  return (lfsr ^ lcg ^ now);
}


static int
mg_poll(struct mg_pollfd *pfd,
        unsigned int n,
        int milliseconds,
        const stop_flag_t *stop_flag)
{
  /* Call poll, but only for a maximum time of a few seconds.
   * This will allow to stop the server after some seconds, instead
   * of having to wait for a long socket timeout. */
  int ms_now = SOCKET_TIMEOUT_QUANTUM; /* Sleep quantum in ms */

  int check_pollerr = 0;
  if ((n == 1) && ((pfd[0].events & POLLERR) == 0)) {
    /* If we wait for only one file descriptor, wait on error as well */
    pfd[0].events |= POLLERR;
    check_pollerr = 1;
  }

  do {
    int result;

    if (!STOP_FLAG_IS_ZERO(&*stop_flag)) {
      /* Shut down signal */
      return -2;
    }

    if ((milliseconds >= 0) && (milliseconds < ms_now)) {
      ms_now = milliseconds;
    }

    result = poll(pfd, n, ms_now);
    if (result != 0) {
      int err = ERRNO;
      if ((result == 1) || (!ERROR_TRY_AGAIN(err))) {
        /* Poll returned either success (1) or error (-1).
         * Forward both to the caller. */
        if ((check_pollerr)
            && ((pfd[0].revents & (POLLIN | POLLOUT | POLLERR))
                == POLLERR)) {
          /* One and only file descriptor returned error */
          return -1;
        }
        return result;
      }
    }

    /* Poll returned timeout (0). */
    if (milliseconds > 0) {
      milliseconds -= ms_now;
    }

  } while (milliseconds > 0);

  /* timeout: return 0 */
  return 0;
}


/* Write data to the IO channel - opened file descriptor, socket or SSL
 * descriptor.
 * Return value:
 *  >=0 .. number of bytes successfully written
 *   -1 .. timeout
 *   -2 .. error
 */
static int
push_inner(struct mg_context *ctx,
           FILE *fp,
           SOCKET sock,
           SSL *ssl,
           const char *buf,
           int len,
           double timeout)
{
  uint64_t start = 0, now = 0, timeout_ns = 0;
  int n, err;
  unsigned ms_wait = SOCKET_TIMEOUT_QUANTUM; /* Sleep quantum in ms */

#if defined(_WIN32)
  typedef int len_t;
#else
  typedef size_t len_t;
#endif

  if (timeout > 0) {
    now = mg_get_current_time_ns();
    start = now;
    timeout_ns = (uint64_t)(timeout * 1.0E9);
  }

  if (ctx == NULL) {
    return -2;
  }

#if defined(NO_SSL) && !defined(USE_MBEDTLS)
  if (ssl) {
    return -2;
  }
#endif

  /* Try to read until it succeeds, fails, times out, or the server
   * shuts down. */
  for (;;) {

#if defined(USE_MBEDTLS)
    if (ssl != NULL) {
      n = mbed_ssl_write(ssl, (const unsigned char *)buf, len);
      if (n <= 0) {
        if ((n == MBEDTLS_ERR_SSL_WANT_READ)
            || (n == MBEDTLS_ERR_SSL_WANT_WRITE)
            || n == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
          n = 0;
        } else {
          fprintf(stderr, "SSL write failed, error %d\n", n);
          return -2;
        }
      } else {
        err = 0;
      }
    } else
#elif !defined(NO_SSL)
    if (ssl != NULL) {
      ERR_clear_error();
      n = SSL_write(ssl, buf, len);
      if (n <= 0) {
        err = SSL_get_error(ssl, n);
        if ((err == SSL_ERROR_SYSCALL) && (n == -1)) {
          err = ERRNO;
        } else if ((err == SSL_ERROR_WANT_READ)
                   || (err == SSL_ERROR_WANT_WRITE)) {
          n = 0;
        } else {
          DEBUG_TRACE("SSL_write() failed, error %d", err);
          ERR_clear_error();
          return -2;
        }
        ERR_clear_error();
      } else {
        err = 0;
      }
    } else
#endif

        if (fp != NULL) {
      n = (int)fwrite(buf, 1, (size_t)len, fp);
      if (ferror(fp)) {
        n = -1;
        err = ERRNO;
      } else {
        err = 0;
      }
    } else {
      n = (int)send(sock, buf, (len_t)len, MSG_NOSIGNAL);
      err = (n < 0) ? ERRNO : 0;
      if (ERROR_TRY_AGAIN(err)) {
        err = 0;
        n = 0;
      }
      if (n < 0) {
        /* shutdown of the socket at client side */
        return -2;
      }
    }

    if (!STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
      return -2;
    }

    if ((n > 0) || ((n == 0) && (len == 0))) {
      /* some data has been read, or no data was requested */
      return n;
    }
    if (n < 0) {
      /* socket error - check errno */
      DEBUG_TRACE("send() failed, error %d", err);

      /* TODO (mid): error handling depending on the error code.
       * These codes are different between Windows and Linux.
       * Currently there is no problem with failing send calls,
       * if there is a reproducible situation, it should be
       * investigated in detail.
       */
      return -2;
    }

    /* Only in case n=0 (timeout), repeat calling the write function */

    /* If send failed, wait before retry */
    if (fp != NULL) {
      /* For files, just wait a fixed time.
       * Maybe it helps, maybe not. */
      mg_sleep(5);
    } else {
      /* For sockets, wait for the socket using poll */
      struct mg_pollfd pfd[1];
      int pollres;

      pfd[0].fd = sock;
      pfd[0].events = POLLOUT;
      pollres = mg_poll(pfd, 1, (int)(ms_wait), &(ctx->stop_flag));
      if (!STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
        return -2;
      }
      if (pollres > 0) {
        continue;
      }
    }

    if (timeout > 0) {
      now = mg_get_current_time_ns();
      if ((now - start) > timeout_ns) {
        /* Timeout */
        break;
      }
    }
  }

  (void)err; /* Avoid unused warning if NO_SSL is set and DEBUG_TRACE is not
             used */

  return -1;
}


static int
push_all(struct mg_context *ctx,
         FILE *fp,
         SOCKET sock,
         SSL *ssl,
         const char *buf,
         int len)
{
  double timeout = -1.0;
  int n, nwritten = 0;

  if (ctx == NULL) {
    return -1;
  }

  if (ctx->dd.config[REQUEST_TIMEOUT]) {
    timeout = atoi(ctx->dd.config[REQUEST_TIMEOUT]) / 1000.0;
  }
  if (timeout <= 0.0) {
    timeout = strtod(config_options[REQUEST_TIMEOUT].default_value, NULL)
              / 1000.0;
  }

  while ((len > 0) && STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
    n = push_inner(ctx, fp, sock, ssl, buf + nwritten, len, timeout);
    if (n < 0) {
      if (nwritten == 0) {
        nwritten = -1; /* Propagate the error */
      }
      break;
    } else if (n == 0) {
      break; /* No more data to write */
    } else {
      nwritten += n;
      len -= n;
    }
  }

  return nwritten;
}


/* Read from IO channel - opened file descriptor, socket, or SSL descriptor.
 * Return value:
 *  >=0 .. number of bytes successfully read
 *   -1 .. timeout
 *   -2 .. error
 */
static int
pull_inner(FILE *fp,
           struct mg_connection *conn,
           char *buf,
           int len,
           double timeout)
{
  int nread, err = 0;

#if defined(_WIN32)
  typedef int len_t;
#else
  typedef size_t len_t;
#endif

  /* We need an additional wait loop around this, because in some cases
   * with TLSwe may get data from the socket but not from SSL_read.
   * In this case we need to repeat at least once.
   */

  if (fp != NULL) {
    /* Use read() instead of fread(), because if we're reading from the
     * CGI pipe, fread() may block until IO buffer is filled up. We
     * cannot afford to block and must pass all read bytes immediately
     * to the client. */
    nread = (int)read(fileno(fp), buf, (size_t)len);

    err = (nread < 0) ? ERRNO : 0;
    if ((nread == 0) && (len > 0)) {
      /* Should get data, but got EOL */
      return -2;
    }

#if defined(USE_MBEDTLS)
  } else if (conn->ssl != NULL) {
    struct mg_pollfd pfd[1];
    int to_read;
    int pollres;

    to_read = mbedtls_ssl_get_bytes_avail(conn->ssl);

    if (to_read > 0) {
      /* We already know there is no more data buffered in conn->buf
       * but there is more available in the SSL layer. So don't poll
       * conn->client.sock yet. */

      pollres = 1;
      if (to_read > len)
        to_read = len;
    } else {
      pfd[0].fd = conn->client.sock;
      pfd[0].events = POLLIN;

      to_read = len;

      pollres = mg_poll(pfd,
                        1,
                        (int)(timeout * 1000.0),
                        &(conn->phys_ctx->stop_flag));

      if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
        return -2;
      }
    }

    if (pollres > 0) {
      nread = mbed_ssl_read(conn->ssl, (unsigned char *)buf, to_read);
      if (nread <= 0) {
        if ((nread == MBEDTLS_ERR_SSL_WANT_READ)
            || (nread == MBEDTLS_ERR_SSL_WANT_WRITE)
            || nread == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
          nread = 0;
        } else {
          fprintf(stderr, "SSL read failed, error %d\n", nread);
          return -2;
        }
      } else {
        err = 0;
      }

    } else if (pollres < 0) {
      /* Error */
      return -2;
    } else {
      /* pollres = 0 means timeout */
      nread = 0;
    }

#elif !defined(NO_SSL)
  } else if (conn->ssl != NULL) {
    int ssl_pending;
    struct mg_pollfd pfd[1];
    int pollres;

    if ((ssl_pending = SSL_pending(conn->ssl)) > 0) {
      /* We already know there is no more data buffered in conn->buf
       * but there is more available in the SSL layer. So don't poll
       * conn->client.sock yet. */
      if (ssl_pending > len) {
        ssl_pending = len;
      }
      pollres = 1;
    } else {
      pfd[0].fd = conn->client.sock;
      pfd[0].events = POLLIN;
      pollres = mg_poll(pfd,
                        1,
                        (int)(timeout * 1000.0),
                        &(conn->phys_ctx->stop_flag));
      if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
        return -2;
      }
    }
    if (pollres > 0) {
      ERR_clear_error();
      nread =
          SSL_read(conn->ssl, buf, (ssl_pending > 0) ? ssl_pending : len);
      if (nread <= 0) {
        err = SSL_get_error(conn->ssl, nread);
        if ((err == SSL_ERROR_SYSCALL) && (nread == -1)) {
          err = ERRNO;
        } else if ((err == SSL_ERROR_WANT_READ)
                   || (err == SSL_ERROR_WANT_WRITE)) {
          nread = 0;
        } else {
          /* All errors should return -2 */
          DEBUG_TRACE("SSL_read() failed, error %d", err);
          ERR_clear_error();
          return -2;
        }
        ERR_clear_error();
      } else {
        err = 0;
      }
    } else if (pollres < 0) {
      /* Error */
      return -2;
    } else {
      /* pollres = 0 means timeout */
      nread = 0;
    }
#endif

  } else {
    struct mg_pollfd pfd[1];
    int pollres;

    pfd[0].fd = conn->client.sock;
    pfd[0].events = POLLIN;
    pollres = mg_poll(pfd,
                      1,
                      (int)(timeout * 1000.0),
                      &(conn->phys_ctx->stop_flag));
    if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
      return -2;
    }
    if (pollres > 0) {
      nread = (int)recv(conn->client.sock, buf, (len_t)len, 0);
      err = (nread < 0) ? ERRNO : 0;
      if (nread <= 0) {
        /* shutdown of the socket at client side */
        return -2;
      }
    } else if (pollres < 0) {
      /* error calling poll */
      return -2;
    } else {
      /* pollres = 0 means timeout */
      nread = 0;
    }
  }

  if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
    return -2;
  }

  if ((nread > 0) || ((nread == 0) && (len == 0))) {
    /* some data has been read, or no data was requested */
    return nread;
  }

  if (nread < 0) {
    /* socket error - check errno */
#if defined(_WIN32)
    if (err == WSAEWOULDBLOCK) {
      /* TODO (low): check if this is still required */
      /* standard case if called from close_socket_gracefully */
      return -2;
    } else if (err == WSAETIMEDOUT) {
      /* TODO (low): check if this is still required */
      /* timeout is handled by the while loop  */
      return 0;
    } else if (err == WSAECONNABORTED) {
      /* See https://www.chilkatsoft.com/p/p_299.asp */
      return -2;
    } else {
      DEBUG_TRACE("recv() failed, error %d", err);
      return -2;
    }
#else
    /* TODO: POSIX returns either EAGAIN or EWOULDBLOCK in both cases,
     * if the timeout is reached and if the socket was set to non-
     * blocking in close_socket_gracefully, so we can not distinguish
     * here. We have to wait for the timeout in both cases for now.
     */
    if (ERROR_TRY_AGAIN(err)) {
      /* TODO (low): check if this is still required */
      /* EAGAIN/EWOULDBLOCK:
       * standard case if called from close_socket_gracefully
       * => should return -1 */
      /* or timeout occurred
       * => the code must stay in the while loop */

      /* EINTR can be generated on a socket with a timeout set even
       * when SA_RESTART is effective for all relevant signals
       * (see signal(7)).
       * => stay in the while loop */
    } else {
      DEBUG_TRACE("recv() failed, error %d", err);
      return -2;
    }
#endif
  }

  /* Timeout occurred, but no data available. */
  return -1;
}


static int
pull_all(FILE *fp, struct mg_connection *conn, char *buf, int len)
{
  int n, nread = 0;
  double timeout = -1.0;
  uint64_t start_time = 0, now = 0, timeout_ns = 0;

  if (conn->dom_ctx->config[REQUEST_TIMEOUT]) {
    timeout = atoi(conn->dom_ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }
  if (timeout <= 0.0) {
    timeout = strtod(config_options[REQUEST_TIMEOUT].default_value, NULL)
              / 1000.0;
  }
  start_time = mg_get_current_time_ns();
  timeout_ns = (uint64_t)(timeout * 1.0E9);

  while ((len > 0) && STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
    n = pull_inner(fp, conn, buf + nread, len, timeout);
    if (n == -2) {
      if (nread == 0) {
        nread = -1; /* Propagate the error */
      }
      break;
    } else if (n == -1) {
      /* timeout */
      if (timeout >= 0.0) {
        now = mg_get_current_time_ns();
        if ((now - start_time) <= timeout_ns) {
          continue;
        }
      }
      break;
    } else if (n == 0) {
      break; /* No more data to read */
    } else {
      nread += n;
      len -= n;
    }
  }

  return nread;
}


static void
discard_unread_request_data(struct mg_connection *conn)
{
  char buf[MG_BUF_LEN];

  while (mg_read(conn, buf, sizeof(buf)) > 0)
    ;
}


static int
mg_read_inner(struct mg_connection *conn, void *buf, size_t len)
{
  int64_t content_len, n, buffered_len, nread;
  int64_t len64 =
      (int64_t)((len > INT_MAX) ? INT_MAX : len); /* since the return value is
                                                   * int, we may not read more
                                                   * bytes */
  const char *body;

  if (conn == NULL) {
    return 0;
  }

  /* If Content-Length is not set for a response with body data,
   * we do not know in advance how much data should be read. */
  content_len = conn->content_len;
  if (content_len < 0) {
    /* The body data is completed when the connection is closed. */
    content_len = INT64_MAX;
  }

  nread = 0;
  if (conn->consumed_content < content_len) {
    /* Adjust number of bytes to read. */
    int64_t left_to_read = content_len - conn->consumed_content;
    if (left_to_read < len64) {
      /* Do not read more than the total content length of the
       * request.
       */
      len64 = left_to_read;
    }

    /* Return buffered data */
    buffered_len = (int64_t)(conn->data_len) - (int64_t)conn->request_len
                   - conn->consumed_content;
    if (buffered_len > 0) {
      if (len64 < buffered_len) {
        buffered_len = len64;
      }
      body = conn->buf + conn->request_len + conn->consumed_content;
      memcpy(buf, body, (size_t)buffered_len);
      len64 -= buffered_len;
      conn->consumed_content += buffered_len;
      nread += buffered_len;
      buf = (char *)buf + buffered_len;
    }

    /* We have returned all buffered data. Read new data from the remote
     * socket.
     */
    if ((n = pull_all(NULL, conn, (char *)buf, (int)len64)) >= 0) {
      conn->consumed_content += n;
      nread += n;
    } else {
      nread = ((nread > 0) ? nread : n);
    }
  }
  return (int)nread;
}


/* Forward declarations */
static void handle_request(struct mg_connection *);
static void log_access(const struct mg_connection *);


/* Handle request, update statistics and call access log */
static void
handle_request_stat_log(struct mg_connection *conn)
{
#if defined(USE_SERVER_STATS)
  struct timespec tnow;
  conn->conn_state = 4; /* processing */
#endif

  handle_request(conn);


#if defined(USE_SERVER_STATS)
  conn->conn_state = 5; /* processed */

  clock_gettime(CLOCK_MONOTONIC, &tnow);
  conn->processing_time = mg_difftimespec(&tnow, &(conn->req_time));

  mg_atomic_add64(&(conn->phys_ctx->total_data_read), conn->consumed_content);
  mg_atomic_add64(&(conn->phys_ctx->total_data_written),
                  conn->num_bytes_sent);
#endif

  DEBUG_TRACE("%s", "handle_request done");

  if (conn->phys_ctx->callbacks.end_request != NULL) {
    conn->phys_ctx->callbacks.end_request(conn, conn->status_code);
    DEBUG_TRACE("%s", "end_request callback done");
  }
  log_access(conn);
}


#if defined(USE_HTTP2)
#if defined(NO_SSL)
#error "HTTP2 requires ALPN, ALPN requires SSL/TLS"
#endif
#define USE_ALPN
#include "http2.inl"
/* Not supported with HTTP/2 */
#define HTTP1_only                                                             \
  {                                                                          \
    if (conn->protocol_type == PROTOCOL_TYPE_HTTP2) {                      \
      http2_must_use_http1(conn);                                        \
      DEBUG_TRACE("%s", "must use HTTP/1.x");                            \
      return;                                                            \
    }                                                                      \
  }
#else
#define HTTP1_only
#endif


CIVETWEB_API int
mg_read(struct mg_connection *conn, void *buf, size_t len)
{
  if (len > INT_MAX) {
    len = INT_MAX;
  }

  if (conn == NULL) {
    return 0;
  }

  if (conn->is_chunked) {
    size_t all_read = 0;

    while (len > 0) {
      if (conn->is_chunked >= 3) {
        /* No more data left to read */
        return 0;
      }
      if (conn->is_chunked != 1) {
        /* Has error */
        return -1;
      }

      if (conn->consumed_content != conn->content_len) {
        /* copy from the current chunk */
        int read_ret = mg_read_inner(conn, (char *)buf + all_read, len);

        if (read_ret < 1) {
          /* read error */
          conn->is_chunked = 2;
          return -1;
        }

        all_read += (size_t)read_ret;
        len -= (size_t)read_ret;

        if (conn->consumed_content == conn->content_len) {
          /* Add data bytes in the current chunk have been read,
           * so we are expecting \r\n now. */
          char x[2];
          conn->content_len += 2;
          if ((mg_read_inner(conn, x, 2) != 2) || (x[0] != '\r')
              || (x[1] != '\n')) {
            /* Protocol violation */
            conn->is_chunked = 2;
            return -1;
          }
        }

      } else {
        /* fetch a new chunk */
        size_t i;
        char lenbuf[64];
        char *end = NULL;
        unsigned long chunkSize = 0;

        for (i = 0; i < (sizeof(lenbuf) - 1); i++) {
          conn->content_len++;
          if (mg_read_inner(conn, lenbuf + i, 1) != 1) {
            lenbuf[i] = 0;
          }
          if ((i > 0) && (lenbuf[i] == ';'))
          {
            // chunk extension --> skip chars until next CR
            //
            // RFC 2616, 3.6.1 Chunked Transfer Coding
              // (https://www.rfc-editor.org/rfc/rfc2616#page-25)
            //
            // chunk          = chunk-size [ chunk-extension ] CRLF
            //                  chunk-data CRLF
            // ...
            // chunk-extension= *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
            do
              ++conn->content_len;
            while (mg_read_inner(conn, lenbuf + i, 1) == 1 &&
                 lenbuf[i] != '\r');
          }
          if ((i > 0) && (lenbuf[i] == '\r')
              && (lenbuf[i - 1] != '\r')) {
            continue;
          }
          if ((i > 1) && (lenbuf[i] == '\n')
              && (lenbuf[i - 1] == '\r')) {
            lenbuf[i + 1] = 0;
            chunkSize = strtoul(lenbuf, &end, 16);
            if (chunkSize == 0) {
              /* regular end of content */
              conn->is_chunked = 3;
            }
            break;
          }
          if (!isxdigit((unsigned char)lenbuf[i])) {
            /* illegal character for chunk length */
            conn->is_chunked = 2;
            return -1;
          }
        }
        if ((end == NULL) || (*end != '\r')) {
          /* chunksize not set correctly */
          conn->is_chunked = 2;
          return -1;
        }
        if (conn->is_chunked == 3) {
          /* try discarding trailer for keep-alive */

          // We found the last chunk (length 0) including the
          // CRLF that terminates that chunk. Now follows a possibly
          // empty trailer and a final CRLF.
          //
          // see RFC 2616, 3.6.1 Chunked Transfer Coding
          // (https://www.rfc-editor.org/rfc/rfc2616#page-25)
          //
          // Chunked-Body   = *chunk
          //                  last-chunk
          //                  trailer
          //                  CRLF
          // ...
          // last-chunk     = 1*("0") [ chunk-extension ] CRLF
          // ...
          // trailer        = *(entity-header CRLF)

          int crlf_count = 2;  // one CRLF already determined

          while (crlf_count < 4 && conn->is_chunked == 3) {
            ++conn->content_len;
            if (mg_read_inner(conn, lenbuf, 1) == 1) {
              if ((crlf_count == 0 || crlf_count == 2)) {
                if (lenbuf[0] == '\r')
                  ++crlf_count;
                else
                  crlf_count = 0;
              }
              else {
                // previous character was a CR
                // --> next character must be LF

                if (lenbuf[0] == '\n')
                  ++crlf_count;
                else
                  conn->is_chunked = 2;
              }
            }
            else
              // premature end of trailer
              conn->is_chunked = 2;
          }

          if (conn->is_chunked == 2)
            return -1;
          else
            conn->is_chunked = 4;

          break;
        }

        /* append a new chunk */
        conn->content_len += (int64_t)chunkSize;
      }
    }

    return (int)all_read;
  }
  return mg_read_inner(conn, buf, len);
}


CIVETWEB_API int
mg_write(struct mg_connection *conn, const void *buf, size_t len)
{
  time_t now;
  int n, total, allowed;

  if (conn == NULL) {
    return 0;
  }
  if (len > INT_MAX) {
    return -1;
  }

  /* Mark connection as "data sent" */
  conn->request_state = 10;
#if defined(USE_HTTP2)
  if (conn->protocol_type == PROTOCOL_TYPE_HTTP2) {
    http2_data_frame_head(conn, len, 0);
  }
#endif

  if (conn->throttle > 0) {
    if ((now = time(NULL)) != conn->last_throttle_time) {
      conn->last_throttle_time = now;
      conn->last_throttle_bytes = 0;
    }
    allowed = conn->throttle - conn->last_throttle_bytes;
    if (allowed > (int)len) {
      allowed = (int)len;
    }

    total = push_all(conn->phys_ctx,
                     NULL,
                     conn->client.sock,
                     conn->ssl,
                     (const char *)buf,
                     allowed);

    if (total == allowed) {

      buf = (const char *)buf + total;
      conn->last_throttle_bytes += total;
      while ((total < (int)len)
             && STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
        allowed = (conn->throttle > ((int)len - total))
                      ? (int)len - total
                      : conn->throttle;

        n = push_all(conn->phys_ctx,
                     NULL,
                     conn->client.sock,
                     conn->ssl,
                     (const char *)buf,
                     allowed);

        if (n != allowed) {
          break;
        }
        sleep(1);
        conn->last_throttle_bytes = allowed;
        conn->last_throttle_time = time(NULL);
        buf = (const char *)buf + n;
        total += n;
      }
    }
  } else {
    total = push_all(conn->phys_ctx,
                     NULL,
                     conn->client.sock,
                     conn->ssl,
                     (const char *)buf,
                     (int)len);
  }
  if (total > 0) {
    conn->num_bytes_sent += total;
  }
  return total;
}


/* Send a chunk, if "Transfer-Encoding: chunked" is used */
CIVETWEB_API int
mg_send_chunk(struct mg_connection *conn,
              const char *chunk,
              unsigned int chunk_len)
{
  char lenbuf[16];
  size_t lenbuf_len;
  int ret;
  int t;

  /* First store the length information in a text buffer. */
  sprintf(lenbuf, "%x\r\n", chunk_len);
  lenbuf_len = strlen(lenbuf);

  /* Then send length information, chunk and terminating \r\n. */
  ret = mg_write(conn, lenbuf, lenbuf_len);
  if (ret != (int)lenbuf_len) {
    return -1;
  }
  t = ret;

  ret = mg_write(conn, chunk, chunk_len);
  if (ret != (int)chunk_len) {
    return -1;
  }
  t += ret;

  ret = mg_write(conn, "\r\n", 2);
  if (ret != 2) {
    return -1;
  }
  t += ret;

  return t;
}


#if defined(GCC_DIAGNOSTIC)
/* This block forwards format strings to printf implementations,
 * so we need to disable the format-nonliteral warning. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif


/* Alternative alloc_vprintf() for non-compliant C runtimes */
static int
alloc_vprintf2(char **buf, const char *fmt, va_list ap)
{
  va_list ap_copy;
  size_t size = MG_BUF_LEN / 4;
  int len = -1;

  *buf = NULL;
  while (len < 0) {
    if (*buf) {
      mg_free(*buf);
    }

    size *= 4;
    *buf = (char *)mg_malloc(size);
    if (!*buf) {
      break;
    }

    va_copy(ap_copy, ap);
    len = vsnprintf_impl(*buf, size - 1, fmt, ap_copy);
    va_end(ap_copy);
    (*buf)[size - 1] = 0;
  }

  return len;
}


/* Print message to buffer. If buffer is large enough to hold the message,
 * return buffer. If buffer is to small, allocate large enough buffer on
 * heap,
 * and return allocated buffer. */
static int
alloc_vprintf(char **out_buf,
              char *prealloc_buf,
              size_t prealloc_size,
              const char *fmt,
              va_list ap)
{
  va_list ap_copy;
  int len;

  /* Windows is not standard-compliant, and vsnprintf() returns -1 if
   * buffer is too small. Also, older versions of msvcrt.dll do not have
   * _vscprintf().  However, if size is 0, vsnprintf() behaves correctly.
   * Therefore, we make two passes: on first pass, get required message
   * length.
   * On second pass, actually print the message. */
  va_copy(ap_copy, ap);
  len = vsnprintf_impl(NULL, 0, fmt, ap_copy);
  va_end(ap_copy);

  if (len < 0) {
    /* C runtime is not standard compliant, vsnprintf() returned -1.
     * Switch to alternative code path that uses incremental
     * allocations.
     */
    va_copy(ap_copy, ap);
    len = alloc_vprintf2(out_buf, fmt, ap_copy);
    va_end(ap_copy);

  } else if ((size_t)(len) >= prealloc_size) {
    /* The pre-allocated buffer not large enough. */
    /* Allocate a new buffer. */
    *out_buf = (char *)mg_malloc((size_t)(len) + 1);
    if (!*out_buf) {
      /* Allocation failed. Return -1 as "out of memory" error. */
      return -1;
    }
    /* Buffer allocation successful. Store the string there. */
    va_copy(ap_copy, ap);
    IGNORE_UNUSED_RESULT(
        vsnprintf_impl(*out_buf, (size_t)(len) + 1, fmt, ap_copy));
    va_end(ap_copy);

  } else {
    /* The pre-allocated buffer is large enough.
     * Use it to store the string and return the address. */
    va_copy(ap_copy, ap);
    IGNORE_UNUSED_RESULT(
        vsnprintf_impl(prealloc_buf, prealloc_size, fmt, ap_copy));
    va_end(ap_copy);
    *out_buf = prealloc_buf;
  }

  return len;
}


static int
alloc_printf(char **out_buf, const char *fmt, ...)
{
  va_list ap;
  int result;

  va_start(ap, fmt);
  result = alloc_vprintf(out_buf, NULL, 0, fmt, ap);
  va_end(ap);

  return result;
}


#if defined(GCC_DIAGNOSTIC)
/* Enable format-nonliteral warning again. */
#pragma GCC diagnostic pop
#endif


static int
mg_vprintf(struct mg_connection *conn, const char *fmt, va_list ap)
{
  char mem[MG_BUF_LEN];
  char *buf = NULL;
  int len;

  if ((len = alloc_vprintf(&buf, mem, sizeof(mem), fmt, ap)) > 0) {
    len = mg_write(conn, buf, (size_t)len);
  }
  if (buf != mem) {
    mg_free(buf);
  }

  return len;
}


CIVETWEB_API int
mg_printf(struct mg_connection *conn, const char *fmt, ...)
{
  va_list ap;
  int result;

  va_start(ap, fmt);
  result = mg_vprintf(conn, fmt, ap);
  va_end(ap);

  return result;
}


CIVETWEB_API int
mg_url_decode(const char *src,
              int src_len,
              char *dst,
              int dst_len,
              int is_form_url_encoded)
{
  int i, j, a, b;
#define HEXTOI(x) (isdigit(x) ? (x - '0') : (x - 'W'))

  for (i = j = 0; (i < src_len) && (j < (dst_len - 1)); i++, j++) {
    if ((i < src_len - 2) && (src[i] == '%')
        && isxdigit((unsigned char)src[i + 1])
        && isxdigit((unsigned char)src[i + 2])) {
      a = tolower((unsigned char)src[i + 1]);
      b = tolower((unsigned char)src[i + 2]);
      dst[j] = (char)((HEXTOI(a) << 4) | HEXTOI(b));
      i += 2;
    } else if (is_form_url_encoded && (src[i] == '+')) {
      dst[j] = ' ';
    } else {
      dst[j] = src[i];
    }
  }

  dst[j] = '\0'; /* Null-terminate the destination */

  return (i >= src_len) ? j : -1;
}


/* form url decoding of an entire string */
static void
url_decode_in_place(char *buf)
{
  int len = (int)strlen(buf);
  (void)mg_url_decode(buf, len, buf, len + 1, 1);
}


CIVETWEB_API int
mg_get_var(const char *data,
           size_t data_len,
           const char *name,
           char *dst,
           size_t dst_len)
{
  return mg_get_var2(data, data_len, name, dst, dst_len, 0);
}


CIVETWEB_API int
mg_get_var2(const char *data,
            size_t data_len,
            const char *name,
            char *dst,
            size_t dst_len,
            size_t occurrence)
{
  const char *p, *e, *s;
  size_t name_len;
  int len;

  if ((dst == NULL) || (dst_len == 0)) {
    len = -2;
  } else if ((data == NULL) || (name == NULL) || (data_len == 0)) {
    len = -1;
    dst[0] = '\0';
  } else {
    name_len = strlen(name);
    e = data + data_len;
    len = -1;
    dst[0] = '\0';

    /* data is "var1=val1&var2=val2...". Find variable first */
    for (p = data; p + name_len < e; p++) {
      if (((p == data) || (p[-1] == '&')) && (p[name_len] == '=')
          && !mg_strncasecmp(name, p, name_len) && 0 == occurrence--) {
        /* Point p to variable value */
        p += name_len + 1;

        /* Point s to the end of the value */
        s = (const char *)memchr(p, '&', (size_t)(e - p));
        if (s == NULL) {
          s = e;
        }
        DEBUG_ASSERT(s >= p);
        if (s < p) {
          return -3;
        }

        /* Decode variable into destination buffer */
        len = mg_url_decode(p, (int)(s - p), dst, (int)dst_len, 1);

        /* Redirect error code from -1 to -2 (destination buffer too
         * small). */
        if (len == -1) {
          len = -2;
        }
        break;
      }
    }
  }

  return len;
}


/* split a string "key1=val1&key2=val2" into key/value pairs */
CIVETWEB_API int
mg_split_form_urlencoded(char *data,
                         struct mg_header *form_fields,
                         unsigned num_form_fields)
{
  char *b;
  int i;
  int num = 0;

  if (data == NULL) {
    /* parameter error */
    return -1;
  }

  if ((form_fields == NULL) && (num_form_fields == 0)) {
    /* determine the number of expected fields */
    if (data[0] == 0) {
      return 0;
    }
    /* count number of & to return the number of key-value-pairs */
    num = 1;
    while (*data) {
      if (*data == '&') {
        num++;
      }
      data++;
    }
    return num;
  }

  if ((form_fields == NULL) || ((int)num_form_fields <= 0)) {
    /* parameter error */
    return -1;
  }

  for (i = 0; i < (int)num_form_fields; i++) {
    /* extract key-value pairs from input data */
    while ((*data == ' ') || (*data == '\t')) {
      /* skip initial spaces */
      data++;
    }
    if (*data == 0) {
      /* end of string reached */
      break;
    }
    form_fields[num].name = data;

    /* find & or = */
    b = data;
    while ((*b != 0) && (*b != '&') && (*b != '=')) {
      b++;
    }

    if (*b == 0) {
      /* last key without value */
      form_fields[num].value = NULL;
    } else if (*b == '&') {
      /* mid key without value */
      form_fields[num].value = NULL;
    } else {
      /* terminate string */
      *b = 0;
      /* value starts after '=' */
      data = b + 1;
      form_fields[num].value = data;
    }

    /* new field is stored */
    num++;

    /* find a next key */
    b = strchr(data, '&');
    if (b == 0) {
      /* no more data */
      break;
    } else {
      /* terminate value of last field at '&' */
      *b = 0;
      /* next key-value-pairs starts after '&' */
      data = b + 1;
    }
  }

  /* Decode all values */
  for (i = 0; i < num; i++) {
    if (form_fields[i].name) {
      url_decode_in_place((char *)form_fields[i].name);
    }
    if (form_fields[i].value) {
      url_decode_in_place((char *)form_fields[i].value);
    }
  }

  /* return number of fields found */
  return num;
}


/* HCP24: some changes to compare whole var_name */
CIVETWEB_API int
mg_get_cookie(const char *cookie_header,
              const char *var_name,
              char *dst,
              size_t dst_size)
{
  const char *s, *p, *end;
  int name_len, len = -1;

  if ((dst == NULL) || (dst_size == 0)) {
    return -2;
  }

  dst[0] = '\0';
  if ((var_name == NULL) || ((s = cookie_header) == NULL)) {
    return -1;
  }

  name_len = (int)strlen(var_name);
  end = s + strlen(s);
  for (; (s = mg_strcasestr(s, var_name)) != NULL; s += name_len) {
    if (s[name_len] == '=') {
      /* HCP24: now check is it a substring or a full cookie name */
      if ((s == cookie_header) || (s[-1] == ' ')) {
        s += name_len + 1;
        if ((p = strchr(s, ' ')) == NULL) {
          p = end;
        }
        if (p[-1] == ';') {
          p--;
        }
        if ((*s == '"') && (p[-1] == '"') && (p > s + 1)) {
          s++;
          p--;
        }
        if ((size_t)(p - s) < dst_size) {
          len = (int)(p - s);
          mg_strlcpy(dst, s, (size_t)len + 1);
        } else {
          len = -3;
        }
        break;
      }
    }
  }
  return len;
}


CIVETWEB_API int
mg_base64_encode(const unsigned char *src,
                 size_t src_len,
                 char *dst,
                 size_t *dst_len)
{
  static const char *b64 =
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  size_t i, j;
  int a, b, c;

  if (dst_len != NULL) {
    /* Expected length including 0 termination: */
    /* IN 1 -> OUT 5, IN 2 -> OUT 5, IN 3 -> OUT 5, IN 4 -> OUT 9,
     * IN 5 -> OUT 9, IN 6 -> OUT 9, IN 7 -> OUT 13, etc. */
    size_t expected_len = ((src_len + 2) / 3) * 4 + 1;
    if (*dst_len < expected_len) {
      if (*dst_len > 0) {
        dst[0] = '\0';
      }
      *dst_len = expected_len;
      return 0;
    }
  }

  for (i = j = 0; i < src_len; i += 3) {
    a = src[i];
    b = ((i + 1) >= src_len) ? 0 : src[i + 1];
    c = ((i + 2) >= src_len) ? 0 : src[i + 2];

    dst[j++] = b64[a >> 2];
    dst[j++] = b64[((a & 3) << 4) | (b >> 4)];
    if (i + 1 < src_len) {
      dst[j++] = b64[(b & 15) << 2 | (c >> 6)];
    }
    if (i + 2 < src_len) {
      dst[j++] = b64[c & 63];
    }
  }
  while (j % 4 != 0) {
    dst[j++] = '=';
  }
  dst[j++] = '\0';

  if (dst_len != NULL) {
    *dst_len = (size_t)j;
  }

  /* Return -1 for "OK" */
  return -1;
}


static unsigned char
b64reverse(char letter)
{
  if ((letter >= 'A') && (letter <= 'Z')) {
    return letter - 'A';
  }
  if ((letter >= 'a') && (letter <= 'z')) {
    return letter - 'a' + 26;
  }
  if ((letter >= '0') && (letter <= '9')) {
    return letter - '0' + 52;
  }
  if (letter == '+') {
    return 62;
  }
  if (letter == '/') {
    return 63;
  }
  if (letter == '=') {
    return 255; /* normal end */
  }
  return 254; /* error */
}


CIVETWEB_API int
mg_base64_decode(const char *src,
                 size_t src_len,
                 unsigned char *dst,
                 size_t *dst_len)
{
  size_t i;
  unsigned char a, b, c, d;
  size_t dst_len_limit = (size_t)-1;
  size_t dst_len_used = 0;

  if (dst_len != NULL) {
    dst_len_limit = *dst_len;
    *dst_len = 0;
  }

  for (i = 0; i < src_len; i += 4) {
    /* Read 4 characters from BASE64 string */
    a = b64reverse(src[i]);
    if (a >= 254) {
      return (int)i;
    }

    b = b64reverse(((i + 1) >= src_len) ? 0 : src[i + 1]);
    if (b >= 254) {
      return (int)i + 1;
    }

    c = b64reverse(((i + 2) >= src_len) ? 0 : src[i + 2]);
    if (c == 254) {
      return (int)i + 2;
    }

    d = b64reverse(((i + 3) >= src_len) ? 0 : src[i + 3]);
    if (d == 254) {
      return (int)i + 3;
    }

    /* Add first (of 3) decoded character */
    if (dst_len_used < dst_len_limit) {
      dst[dst_len_used] = (a << 2) + (b >> 4);
    }
    dst_len_used++;

    if (c != 255) {
      if (dst_len_used < dst_len_limit) {

        dst[dst_len_used] = (b << 4) + (c >> 2);
      }
      dst_len_used++;
      if (d != 255) {
        if (dst_len_used < dst_len_limit) {
          dst[dst_len_used] = (c << 6) + d;
        }
        dst_len_used++;
      }
    }
  }

  /* Add terminating zero */
  if (dst_len_used < dst_len_limit) {
    dst[dst_len_used] = '\0';
  }
  dst_len_used++;
  if (dst_len != NULL) {
    *dst_len = dst_len_used;
  }

  if (dst_len_used > dst_len_limit) {
    /* Out of memory */
    return 0;
  }

  /* Return -1 for "OK" */
  return -1;
}


static int
is_put_or_delete_method(const struct mg_connection *conn)
{
  if (conn) {
    const char *s = conn->request_info.request_method;
    if (s != NULL) {
      /* PUT, DELETE, MKCOL, PATCH, LOCK, UNLOCK, PROPPATCH, MOVE, COPY */
      return (!strcmp(s, "PUT") || !strcmp(s, "DELETE")
              || !strcmp(s, "MKCOL") || !strcmp(s, "PATCH")
              || !strcmp(s, "LOCK") || !strcmp(s, "UNLOCK")
              || !strcmp(s, "PROPPATCH") || !strcmp(s, "MOVE")
              || !strcmp(s, "COPY"));
    }
  }
  return 0;
}


static int
is_civetweb_webdav_method(const struct mg_connection *conn)
{
  /* Note: Here we only have to identify the WebDav methods that need special
   * handling in the CivetWeb code - not all methods used in WebDav. In
   * particular, methods used on directories (when using Windows Explorer as
   * WebDav client).
   */
  if (conn) {
    const char *s = conn->request_info.request_method;
    if (s != NULL) {
      /* These are the civetweb builtin DAV methods */
      return (!strcmp(s, "PROPFIND") || !strcmp(s, "PROPPATCH")
              || !strcmp(s, "LOCK") || !strcmp(s, "UNLOCK")
              || !strcmp(s, "MOVE") || !strcmp(s, "COPY"));
    }
  }
  return 0;
}


#if !defined(NO_FILES)
static int
extention_matches_script(
    struct mg_connection *conn, /* in: request (must be valid) */
    const char *filename        /* in: filename  (must be valid) */
)
{
#if !defined(NO_CGI)
  unsigned char cgi_config_idx, inc, max;
#endif

#if defined(USE_LUA)
  if (match_prefix_strlen(conn->dom_ctx->config[LUA_SCRIPT_EXTENSIONS],
                          filename)
      > 0) {
    return 1;
  }
#endif
#if defined(USE_DUKTAPE)
  if (match_prefix_strlen(conn->dom_ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
                          filename)
      > 0) {
    return 1;
  }
#endif
#if !defined(NO_CGI)
  inc = CGI2_EXTENSIONS - CGI_EXTENSIONS;
  max = PUT_DELETE_PASSWORDS_FILE - CGI_EXTENSIONS;
  for (cgi_config_idx = 0; cgi_config_idx < max; cgi_config_idx += inc) {
    if ((conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx] != NULL)
        && (match_prefix_strlen(
                conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx],
                filename)
            > 0)) {
      return 1;
    }
  }
#endif
  /* filename and conn could be unused, if all preocessor conditions
   * are false (no script language supported). */
  (void)filename;
  (void)conn;

  return 0;
}


static int
extention_matches_template_text(
    struct mg_connection *conn, /* in: request (must be valid) */
    const char *filename        /* in: filename  (must be valid) */
)
{
#if defined(USE_LUA)
  if (match_prefix_strlen(conn->dom_ctx->config[LUA_SERVER_PAGE_EXTENSIONS],
                          filename)
      > 0) {
    return 1;
  }
#endif
  if (match_prefix_strlen(conn->dom_ctx->config[SSI_EXTENSIONS], filename)
      > 0) {
    return 1;
  }
  return 0;
}


/* For given directory path, substitute it to valid index file.
 * Return 1 if index file has been found, 0 if not found.
 * If the file is found, it's stats is returned in stp. */
static int
substitute_index_file(struct mg_connection *conn,
                      char *path,
                      size_t path_len,
                      struct mg_file_stat *filestat)
{
  const char *list = conn->dom_ctx->config[INDEX_FILES];
  struct vec filename_vec;
  size_t n = strlen(path);
  int found = 0;

  /* The 'path' given to us points to the directory. Remove all trailing
   * directory separator characters from the end of the path, and
   * then append single directory separator character. */
  while ((n > 0) && (path[n - 1] == '/')) {
    n--;
  }
  path[n] = '/';

  /* Traverse index files list. For each entry, append it to the given
   * path and see if the file exists. If it exists, break the loop */
  while ((list = next_option(list, &filename_vec, NULL)) != NULL) {
    /* Ignore too long entries that may overflow path buffer */
    if ((filename_vec.len + 1) > (path_len - (n + 1))) {
      continue;
    }

    /* Prepare full path to the index file */
    mg_strlcpy(path + n + 1, filename_vec.ptr, filename_vec.len + 1);

    /* Does it exist? */
    if (mg_stat(conn, path, filestat)) {
      /* Yes it does, break the loop */
      found = 1;
      break;
    }
  }

  /* If no index file exists, restore directory path */
  if (!found) {
    path[n] = '\0';
  }

  return found;
}
#endif


static void
interpret_uri(struct mg_connection *conn, /* in/out: request (must be valid) */
              char *filename,             /* out: filename */
              size_t filename_buf_len,    /* in: size of filename buffer */
              struct mg_file_stat *filestat, /* out: file status structure */
              int *is_found,                 /* out: file found (directly) */
              int *is_script_resource,       /* out: handled by a script? */
              int *is_websocket_request,     /* out: websocket connection? */
              int *is_put_or_delete_request, /* out: put/delete a file? */
              int *is_webdav_request,        /* out: webdav request? */
              int *is_template_text          /* out: SSI file or LSP file? */
)
{
  char const *accept_encoding;

#if !defined(NO_FILES)
  const char *uri = conn->request_info.local_uri;
  const char *root = conn->dom_ctx->config[DOCUMENT_ROOT];
  const char *rewrite;
  struct vec a, b;
  ptrdiff_t match_len;
  char gz_path[UTF8_PATH_MAX];
  int truncated;
#if !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE)
  char *tmp_str;
  size_t tmp_str_len, sep_pos;
  int allow_substitute_script_subresources;
#endif
#else
  (void)filename_buf_len; /* unused if NO_FILES is defined */
#endif

  /* Step 1: Set all initially unknown outputs to zero */
  memset(filestat, 0, sizeof(*filestat));
  *filename = 0;
  *is_found = 0;
  *is_script_resource = 0;
  *is_template_text = 0;

  /* Step 2: Classify the request method */
  /* Step 2a: Check if the request attempts to modify the file system */
  *is_put_or_delete_request = is_put_or_delete_method(conn);
  /* Step 2b: Check if the request uses WebDav method that requires special
   * handling */
  *is_webdav_request = is_civetweb_webdav_method(conn);

  /* Step 3: Check if it is a websocket request, and modify the document
   * root if required */
#if defined(USE_WEBSOCKET)
  *is_websocket_request = (conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET);
#if !defined(NO_FILES)
  if ((*is_websocket_request) && conn->dom_ctx->config[WEBSOCKET_ROOT]) {
    root = conn->dom_ctx->config[WEBSOCKET_ROOT];
  }
#endif /* !NO_FILES */
#else  /* USE_WEBSOCKET */
  *is_websocket_request = 0;
#endif /* USE_WEBSOCKET */

  /* Step 4: Check if gzip encoded response is allowed */
  conn->accept_gzip = 0;
  if ((accept_encoding = mg_get_header(conn, "Accept-Encoding")) != NULL) {
    if (strstr(accept_encoding, "gzip") != NULL) {
      conn->accept_gzip = 1;
    }
  }

#if !defined(NO_FILES)
  /* Step 5: If there is no root directory, don't look for files. */
  /* Note that root == NULL is a regular use case here. This occurs,
   * if all requests are handled by callbacks, so the WEBSOCKET_ROOT
   * config is not required. */
  if (root == NULL) {
    /* all file related outputs have already been set to 0, just return
     */
    return;
  }

  /* Step 6: Determine the local file path from the root path and the
   * request uri. */
  /* Using filename_buf_len - 1 because memmove() for PATH_INFO may shift
   * part of the path one byte on the right. */
  truncated = 0;
  mg_snprintf(
      conn, &truncated, filename, filename_buf_len - 1, "%s%s", root, uri);

  if (truncated) {
    goto interpret_cleanup;
  }

  /* Step 7: URI rewriting */
  rewrite = conn->dom_ctx->config[URL_REWRITE_PATTERN];
  while ((rewrite = next_option(rewrite, &a, &b)) != NULL) {
    if ((match_len = match_prefix(a.ptr, a.len, uri)) > 0) {
      mg_snprintf(conn,
                  &truncated,
                  filename,
                  filename_buf_len - 1,
                  "%.*s%s",
                  (int)b.len,
                  b.ptr,
                  uri + match_len);
      break;
    }
  }

  if (truncated) {
    goto interpret_cleanup;
  }

  /* Step 8: Check if the file exists at the server */
  /* Local file path and name, corresponding to requested URI
   * is now stored in "filename" variable. */
  if (mg_stat(conn, filename, filestat)) {
    int uri_len = (int)strlen(uri);
    int is_uri_end_slash = (uri_len > 0) && (uri[uri_len - 1] == '/');

    /* 8.1: File exists. */
    *is_found = 1;

    /* 8.2: Check if it is a script type. */
    if (extention_matches_script(conn, filename)) {
      /* The request addresses a CGI resource, Lua script or
       * server-side javascript.
       * The URI corresponds to the script itself (like
       * /path/script.cgi), and there is no additional resource
       * path (like /path/script.cgi/something).
       * Requests that modify (replace or delete) a resource, like
       * PUT and DELETE requests, should replace/delete the script
       * file.
       * Requests that read or write from/to a resource, like GET and
       * POST requests, should call the script and return the
       * generated response. */
      *is_script_resource = (!*is_put_or_delete_request);
    }

    /* 8.3: Check for SSI and LSP files */
    if (extention_matches_template_text(conn, filename)) {
      /* Same as above, but for *.lsp and *.shtml files. */
      /* A "template text" is a file delivered directly to the client,
       * but with some text tags replaced by dynamic content.
       * E.g. a Server Side Include (SSI) or Lua Page/Lua Server Page
       * (LP, LSP) file. */
      *is_template_text = (!*is_put_or_delete_request);
    }

    /* 8.4: If the request target is a directory, there could be
     * a substitute file (index.html, index.cgi, ...). */
    /* But do not substitute a directory for a WebDav request */
    if (filestat->is_directory && is_uri_end_slash
        && (!*is_webdav_request)) {
      /* Use a local copy here, since substitute_index_file will
       * change the content of the file status */
      struct mg_file_stat tmp_filestat;
      memset(&tmp_filestat, 0, sizeof(tmp_filestat));

      if (substitute_index_file(
              conn, filename, filename_buf_len, &tmp_filestat)) {

        /* Substitute file found. Copy stat to the output, then
         * check if the file is a script file */
        *filestat = tmp_filestat;

        if (extention_matches_script(conn, filename)) {
          /* Substitute file is a script file */
          *is_script_resource = 1;
        } else if (extention_matches_template_text(conn, filename)) {
          /* Substitute file is a LSP or SSI file */
          *is_template_text = 1;
        } else {
          /* Substitute file is a regular file */
          *is_script_resource = 0;
          *is_found = (mg_stat(conn, filename, filestat) ? 1 : 0);
        }
      }
      /* If there is no substitute file, the server could return
       * a directory listing in a later step */
    }
    return;
  }

  /* Step 9: Check for zipped files: */
  /* If we can't find the actual file, look for the file
   * with the same name but a .gz extension. If we find it,
   * use that and set the gzipped flag in the file struct
   * to indicate that the response need to have the content-
   * encoding: gzip header.
   * We can only do this if the browser declares support. */
  if (conn->accept_gzip) {
    mg_snprintf(
        conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", filename);

    if (truncated) {
      goto interpret_cleanup;
    }

    if (mg_stat(conn, gz_path, filestat)) {
      if (filestat) {
        filestat->is_gzipped = 1;
        *is_found = 1;
      }
      /* Currently gz files can not be scripts. */
      return;
    }
  }

#if !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE)
  /* Step 10: Script resources may handle sub-resources */
  /* Support PATH_INFO for CGI scripts. */
  tmp_str_len = strlen(filename);
  tmp_str =
      (char *)mg_malloc_ctx(tmp_str_len + UTF8_PATH_MAX + 1, conn->phys_ctx);
  if (!tmp_str) {
    /* Out of memory */
    goto interpret_cleanup;
  }
  memcpy(tmp_str, filename, tmp_str_len + 1);

  /* Check config, if index scripts may have sub-resources */
  allow_substitute_script_subresources =
      !mg_strcasecmp(conn->dom_ctx->config[ALLOW_INDEX_SCRIPT_SUB_RES],
                     "yes");
  if (*is_webdav_request) {
    /* TO BE DEFINED: Should scripts handle special WebDAV methods lile
     * PROPFIND for their subresources? */
    /* allow_substitute_script_subresources = 0; */
  }

  sep_pos = tmp_str_len;
  while (sep_pos > 0) {
    sep_pos--;
    if (tmp_str[sep_pos] == '/') {
      int is_script = 0, does_exist = 0;

      tmp_str[sep_pos] = 0;
      if (tmp_str[0]) {
        is_script = extention_matches_script(conn, tmp_str);
        does_exist = mg_stat(conn, tmp_str, filestat);
      }

      if (does_exist && is_script) {
        filename[sep_pos] = 0;
        memmove(filename + sep_pos + 2,
                filename + sep_pos + 1,
                strlen(filename + sep_pos + 1) + 1);
        conn->path_info = filename + sep_pos + 1;
        filename[sep_pos + 1] = '/';
        *is_script_resource = 1;
        *is_found = 1;
        break;
      }

      if (allow_substitute_script_subresources) {
        if (substitute_index_file(
                conn, tmp_str, tmp_str_len + UTF8_PATH_MAX, filestat)) {

          /* some intermediate directory has an index file */
          if (extention_matches_script(conn, tmp_str)) {

            size_t script_name_len = strlen(tmp_str);

            /* subres_name read before this memory locatio will be
            overwritten */
            char *subres_name = filename + sep_pos;
            size_t subres_name_len = strlen(subres_name);

            DEBUG_TRACE("Substitute script %s serving path %s",
                        tmp_str,
                        filename);

            /* this index file is a script */
            if ((script_name_len + subres_name_len + 2)
                >= filename_buf_len) {
              mg_free(tmp_str);
              goto interpret_cleanup;
            }

            conn->path_info =
                filename + script_name_len + 1; /* new target */
            memmove(conn->path_info, subres_name, subres_name_len);
            conn->path_info[subres_name_len] = 0;
            memcpy(filename, tmp_str, script_name_len + 1);

            *is_script_resource = 1;
            *is_found = 1;
            break;

          } else {

            DEBUG_TRACE("Substitute file %s serving path %s",
                        tmp_str,
                        filename);

            /* non-script files will not have sub-resources */
            filename[sep_pos] = 0;
            conn->path_info = 0;
            *is_script_resource = 0;
            *is_found = 0;
            break;
          }
        }
      }

      tmp_str[sep_pos] = '/';
    }
  }

  mg_free(tmp_str);

#endif /* !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE) */
#endif /* !defined(NO_FILES) */
  return;

#if !defined(NO_FILES)
/* Reset all outputs */
interpret_cleanup:
  memset(filestat, 0, sizeof(*filestat));
  *filename = 0;
  *is_found = 0;
  *is_script_resource = 0;
  *is_websocket_request = 0;
  *is_put_or_delete_request = 0;
#endif /* !defined(NO_FILES) */
}


/* Check whether full request is buffered. Return:
 * -1  if request or response is malformed
 *  0  if request or response is not yet fully buffered
 * >0  actual request length, including last \r\n\r\n */
static int
get_http_header_len(const char *buf, int buflen)
{
  int i;
  for (i = 0; i < buflen; i++) {
    /* Do an unsigned comparison in some conditions below */
    const unsigned char c = (unsigned char)buf[i];

    if ((c < 128) && ((char)c != '\r') && ((char)c != '\n')
        && !isprint(c)) {
      /* abort scan as soon as one malformed character is found */
      return -1;
    }

    if (i < buflen - 1) {
      if ((buf[i] == '\n') && (buf[i + 1] == '\n')) {
        /* Two newline, no carriage return - not standard compliant,
         * but it should be accepted */
        return i + 2;
      }
    }

    if (i < buflen - 3) {
      if ((buf[i] == '\r') && (buf[i + 1] == '\n') && (buf[i + 2] == '\r')
          && (buf[i + 3] == '\n')) {
        /* Two \r\n - standard compliant */
        return i + 4;
      }
    }
  }

  return 0;
}


#if !defined(NO_CACHING)
/* Convert month to the month number. Return -1 on error, or month number */
static int
get_month_index(const char *s)
{
  size_t i;

  for (i = 0; i < ARRAY_SIZE(month_names); i++) {
    if (!strcmp(s, month_names[i])) {
      return (int)i;
    }
  }

  return -1;
}


/* Parse UTC date-time string, and return the corresponding time_t value. */
static time_t
parse_date_string(const char *datetime)
{
  char month_str[32] = {0};
  int second, minute, hour, day, month, year;
  time_t result = (time_t)0;
  struct tm tm;

  if ((sscanf(datetime,
              "%d/%3s/%d %d:%d:%d",
              &day,
              month_str,
              &year,
              &hour,
              &minute,
              &second)
       == 6)
      || (sscanf(datetime,
                 "%d %3s %d %d:%d:%d",
                 &day,
                 month_str,
                 &year,
                 &hour,
                 &minute,
                 &second)
          == 6)
      || (sscanf(datetime,
                 "%*3s, %d %3s %d %d:%d:%d",
                 &day,
                 month_str,
                 &year,
                 &hour,
                 &minute,
                 &second)
          == 6)
      || (sscanf(datetime,
                 "%d-%3s-%d %d:%d:%d",
                 &day,
                 month_str,
                 &year,
                 &hour,
                 &minute,
                 &second)
          == 6)) {
    month = get_month_index(month_str);
    if ((month >= 0) && (year >= 1970)) {
      memset(&tm, 0, sizeof(tm));
      tm.tm_year = year - 1900;
      tm.tm_mon = month;
      tm.tm_mday = day;
      tm.tm_hour = hour;
      tm.tm_min = minute;
      tm.tm_sec = second;
      result = timegm(&tm);
    }
  }

  return result;
}
#endif /* !NO_CACHING */


/* Pre-process URIs according to RFC + protect against directory disclosure
 * attacks by removing '..', excessive '/' and '\' characters */
static void
remove_dot_segments(char *inout)
{
  /* Windows backend protection
   * (https://tools.ietf.org/html/rfc3986#section-7.3): Replace backslash
   * in URI by slash */
  char *out_end = inout;
  char *in = inout;

  if (!in) {
    /* Param error. */
    return;
  }

  while (*in) {
    if (*in == '\\') {
      *in = '/';
    }
    in++;
  }

  /* Algorithm "remove_dot_segments" from
   * https://tools.ietf.org/html/rfc3986#section-5.2.4 */
  /* Step 1:
   * The input buffer is initialized.
   * The output buffer is initialized to the empty string.
   */
  in = inout;

  /* Step 2:
   * While the input buffer is not empty, loop as follows:
   */
  /* Less than out_end of the inout buffer is used as output, so keep
   * condition: out_end <= in */
  while (*in) {
    /* Step 2a:
     * If the input buffer begins with a prefix of "../" or "./",
     * then remove that prefix from the input buffer;
     */
    if (!strncmp(in, "../", 3)) {
      in += 3;
    } else if (!strncmp(in, "./", 2)) {
      in += 2;
    }
    /* otherwise */
    /* Step 2b:
     * if the input buffer begins with a prefix of "/./" or "/.",
     * where "." is a complete path segment, then replace that
     * prefix with "/" in the input buffer;
     */
    else if (!strncmp(in, "/./", 3)) {
      in += 2;
    } else if (!strcmp(in, "/.")) {
      in[1] = 0;
    }
    /* otherwise */
    /* Step 2c:
     * if the input buffer begins with a prefix of "/../" or "/..",
     * where ".." is a complete path segment, then replace that
     * prefix with "/" in the input buffer and remove the last
     * segment and its preceding "/" (if any) from the output
     * buffer;
     */
    else if (!strncmp(in, "/../", 4)) {
      in += 3;
      if (inout != out_end) {
        /* remove last segment */
        do {
          out_end--;
        } while ((inout != out_end) && (*out_end != '/'));
      }
    } else if (!strcmp(in, "/..")) {
      in[1] = 0;
      if (inout != out_end) {
        /* remove last segment */
        do {
          out_end--;
        } while ((inout != out_end) && (*out_end != '/'));
      }
    }
    /* otherwise */
    /* Step 2d:
     * if the input buffer consists only of "." or "..", then remove
     * that from the input buffer;
     */
    else if (!strcmp(in, ".") || !strcmp(in, "..")) {
      *in = 0;
    }
    /* otherwise */
    /* Step 2e:
     * move the first path segment in the input buffer to the end of
     * the output buffer, including the initial "/" character (if
     * any) and any subsequent characters up to, but not including,
     * the next "/" character or the end of the input buffer.
     */
    else {
      do {
        *out_end = *in;
        out_end++;
        in++;
      } while ((*in != 0) && (*in != '/'));
    }
  }

  /* Step 3:
   * Finally, the output buffer is returned as the result of
   * remove_dot_segments.
   */
  /* Terminate output */
  *out_end = 0;

  /* For Windows, the files/folders "x" and "x." (with a dot but without
   * extension) are identical. Replace all "./" by "/" and remove a "." at
   * the end. Also replace all "//" by "/". Repeat until there is no "./"
   * or "//" anymore.
   */
  out_end = in = inout;
  while (*in) {
    if (*in == '.') {
      /* remove . at the end or preceding of / */
      char *in_ahead = in;
      do {
        in_ahead++;
      } while (*in_ahead == '.');
      if (*in_ahead == '/') {
        in = in_ahead;
        if ((out_end != inout) && (out_end[-1] == '/')) {
          /* remove generated // */
          out_end--;
        }
      } else if (*in_ahead == 0) {
        in = in_ahead;
      } else {
        do {
          *out_end++ = '.';
          in++;
        } while (in != in_ahead);
      }
    } else if (*in == '/') {
      /* replace // by / */
      *out_end++ = '/';
      do {
        in++;
      } while (*in == '/');
    } else {
      *out_end++ = *in;
      in++;
    }
  }
  *out_end = 0;
}


static const struct {
  const char *extension;
  size_t ext_len;
  const char *mime_type;
} builtin_mime_types[] = {
    /* IANA registered MIME types
     * (http://www.iana.org/assignments/media-types)
     * application types */
    {".bin", 4, "application/octet-stream"},
    {".deb", 4, "application/octet-stream"},
    {".dmg", 4, "application/octet-stream"},
    {".dll", 4, "application/octet-stream"},
    {".doc", 4, "application/msword"},
    {".eps", 4, "application/postscript"},
    {".exe", 4, "application/octet-stream"},
    {".iso", 4, "application/octet-stream"},
    {".js", 3, "application/javascript"},
    {".json", 5, "application/json"},
    {".msi", 4, "application/octet-stream"},
    {".pdf", 4, "application/pdf"},
    {".ps", 3, "application/postscript"},
    {".rtf", 4, "application/rtf"},
    {".xhtml", 6, "application/xhtml+xml"},
    {".xsl", 4, "application/xml"},
    {".xslt", 5, "application/xml"},

    /* fonts */
    {".ttf", 4, "application/font-sfnt"},
    {".cff", 4, "application/font-sfnt"},
    {".otf", 4, "application/font-sfnt"},
    {".aat", 4, "application/font-sfnt"},
    {".sil", 4, "application/font-sfnt"},
    {".pfr", 4, "application/font-tdpfr"},
    {".woff", 5, "application/font-woff"},
    {".woff2", 6, "application/font-woff2"},

    /* audio */
    {".mp3", 4, "audio/mpeg"},
    {".oga", 4, "audio/ogg"},
    {".ogg", 4, "audio/ogg"},

    /* image */
    {".gif", 4, "image/gif"},
    {".ief", 4, "image/ief"},
    {".jpeg", 5, "image/jpeg"},
    {".jpg", 4, "image/jpeg"},
    {".jpm", 4, "image/jpm"},
    {".jpx", 4, "image/jpx"},
    {".png", 4, "image/png"},
    {".svg", 4, "image/svg+xml"},
    {".tif", 4, "image/tiff"},
    {".tiff", 5, "image/tiff"},

    /* model */
    {".wrl", 4, "model/vrml"},

    /* text */
    {".css", 4, "text/css"},
    {".csv", 4, "text/csv"},
    {".htm", 4, "text/html"},
    {".html", 5, "text/html"},
    {".sgm", 4, "text/sgml"},
    {".shtm", 5, "text/html"},
    {".shtml", 6, "text/html"},
    {".txt", 4, "text/plain"},
    {".xml", 4, "text/xml"},

    /* video */
    {".mov", 4, "video/quicktime"},
    {".mp4", 4, "video/mp4"},
    {".mpeg", 5, "video/mpeg"},
    {".mpg", 4, "video/mpeg"},
    {".ogv", 4, "video/ogg"},
    {".qt", 3, "video/quicktime"},

    /* not registered types
     * (http://reference.sitepoint.com/html/mime-types-full,
     * http://www.hansenb.pdx.edu/DMKB/dict/tutorials/mime_typ.php, ..) */
    {".arj", 4, "application/x-arj-compressed"},
    {".gz", 3, "application/x-gunzip"},
    {".rar", 4, "application/x-arj-compressed"},
    {".swf", 4, "application/x-shockwave-flash"},
    {".tar", 4, "application/x-tar"},
    {".tgz", 4, "application/x-tar-gz"},
    {".torrent", 8, "application/x-bittorrent"},
    {".ppt", 4, "application/x-mspowerpoint"},
    {".xls", 4, "application/x-msexcel"},
    {".zip", 4, "application/x-zip-compressed"},
    {".aac",
     4,
     "audio/aac"}, /* http://en.wikipedia.org/wiki/Advanced_Audio_Coding */
    {".flac", 5, "audio/flac"},
    {".aif", 4, "audio/x-aif"},
    {".m3u", 4, "audio/x-mpegurl"},
    {".mid", 4, "audio/x-midi"},
    {".ra", 3, "audio/x-pn-realaudio"},
    {".ram", 4, "audio/x-pn-realaudio"},
    {".wav", 4, "audio/x-wav"},
    {".bmp", 4, "image/bmp"},
    {".ico", 4, "image/x-icon"},
    {".pct", 4, "image/x-pct"},
    {".pict", 5, "image/pict"},
    {".rgb", 4, "image/x-rgb"},
    {".webm", 5, "video/webm"}, /* http://en.wikipedia.org/wiki/WebM */
    {".asf", 4, "video/x-ms-asf"},
    {".avi", 4, "video/x-msvideo"},
    {".m4v", 4, "video/x-m4v"},
    {NULL, 0, NULL}};


CIVETWEB_API const char *
mg_get_builtin_mime_type(const char *path)
{
  const char *ext;
  size_t i, path_len;

  path_len = strlen(path);

  for (i = 0; builtin_mime_types[i].extension != NULL; i++) {
    ext = path + (path_len - builtin_mime_types[i].ext_len);
    if ((path_len > builtin_mime_types[i].ext_len)
        && (mg_strcasecmp(ext, builtin_mime_types[i].extension) == 0)) {
      return builtin_mime_types[i].mime_type;
    }
  }

  return "text/plain";
}


/* Look at the "path" extension and figure what mime type it has.
 * Store mime type in the vector. */
static void
get_mime_type(struct mg_connection *conn, const char *path, struct vec *vec)
{
  struct vec ext_vec, mime_vec;
  const char *list, *ext;
  size_t path_len;

  path_len = strlen(path);

  if ((conn == NULL) || (vec == NULL)) {
    if (vec != NULL) {
      memset(vec, '\0', sizeof(struct vec));
    }
    return;
  }

  /* Scan user-defined mime types first, in case user wants to
   * override default mime types. */
  list = conn->dom_ctx->config[EXTRA_MIME_TYPES];
  while ((list = next_option(list, &ext_vec, &mime_vec)) != NULL) {
    /* ext now points to the path suffix */
    ext = path + path_len - ext_vec.len;
    if (mg_strncasecmp(ext, ext_vec.ptr, ext_vec.len) == 0) {
      *vec = mime_vec;
      return;
    }
  }

  vec->ptr = mg_get_builtin_mime_type(path);
  vec->len = strlen(vec->ptr);
}


/* Stringify binary data. Output buffer must be twice as big as input,
 * because each byte takes 2 bytes in string representation */
static void
bin2str(char *to, const unsigned char *p, size_t len)
{
  static const char *hex = "0123456789abcdef";

  for (; len--; p++) {
    *to++ = hex[p[0] >> 4];
    *to++ = hex[p[0] & 0x0f];
  }
  *to = '\0';
}


/* Return stringified MD5 hash for list of strings. Buffer must be 33 bytes.
 */
CIVETWEB_API char *
mg_md5(char buf[33], ...)
{
  md5_byte_t hash[16];
  const char *p;
  va_list ap;
  md5_state_t ctx;

  md5_init(&ctx);

  va_start(ap, buf);
  while ((p = va_arg(ap, const char *)) != NULL) {
    md5_append(&ctx, (const md5_byte_t *)p, strlen(p));
  }
  va_end(ap);

  md5_finish(&ctx, hash);
  bin2str(buf, hash, sizeof(hash));
  return buf;
}


/* Check the user's password, return 1 if OK */
static int
check_password_digest(const char *method,
                      const char *ha1,
                      const char *uri,
                      const char *nonce,
                      const char *nc,
                      const char *cnonce,
                      const char *qop,
                      const char *response)
{
  char ha2[32 + 1], expected_response[32 + 1];

  /* Some of the parameters may be NULL */
  if ((method == NULL) || (nonce == NULL) || (nc == NULL) || (cnonce == NULL)
      || (qop == NULL) || (response == NULL)) {
    return 0;
  }

  /* NOTE(lsm): due to a bug in MSIE, we do not compare the URI */
  if (strlen(response) != 32) {
    return 0;
  }

  mg_md5(ha2, method, ":", uri, NULL);
  mg_md5(expected_response,
         ha1,
         ":",
         nonce,
         ":",
         nc,
         ":",
         cnonce,
         ":",
         qop,
         ":",
         ha2,
         NULL);

  return mg_strcasecmp(response, expected_response) == 0;
}


#if !defined(NO_FILESYSTEMS)
/* Use the global passwords file, if specified by auth_gpass option,
 * or search for .htpasswd in the requested directory. */
static void
open_auth_file(struct mg_connection *conn,
               const char *path,
               struct mg_file *filep)
{
  if ((conn != NULL) && (conn->dom_ctx != NULL)) {
    char name[UTF8_PATH_MAX];
    const char *p, *e,
        *gpass = conn->dom_ctx->config[GLOBAL_PASSWORDS_FILE];
    int truncated;

    if (gpass != NULL) {
      /* Use global passwords file */
      if (!mg_fopen(conn, gpass, MG_FOPEN_MODE_READ, filep)) {
#if defined(DEBUG)
        /* Use mg_cry_internal here, since gpass has been
         * configured. */
        mg_cry_internal(conn, "fopen(%s): %s", gpass, strerror(ERRNO));
#endif
      }
      /* Important: using local struct mg_file to test path for
       * is_directory flag. If filep is used, mg_stat() makes it
       * appear as if auth file was opened.
       * TODO(mid): Check if this is still required after rewriting
       * mg_stat */
    } else if (mg_stat(conn, path, &filep->stat)
               && filep->stat.is_directory) {
      mg_snprintf(conn,
                  &truncated,
                  name,
                  sizeof(name),
                  "%s/%s",
                  path,
                  PASSWORDS_FILE_NAME);

      if (truncated || !mg_fopen(conn, name, MG_FOPEN_MODE_READ, filep)) {
#if defined(DEBUG)
        /* Don't use mg_cry_internal here, but only a trace, since
         * this is a typical case. It will occur for every directory
         * without a password file. */
        DEBUG_TRACE("fopen(%s): %s", name, strerror(ERRNO));
#endif
      }
    } else {
      /* Try to find .htpasswd in requested directory. */
      for (p = path, e = p + strlen(p) - 1; e > p; e--) {
        if (e[0] == '/') {
          break;
        }
      }
      mg_snprintf(conn,
                  &truncated,
                  name,
                  sizeof(name),
                  "%.*s/%s",
                  (int)(e - p),
                  p,
                  PASSWORDS_FILE_NAME);

      if (truncated || !mg_fopen(conn, name, MG_FOPEN_MODE_READ, filep)) {
#if defined(DEBUG)
        /* Don't use mg_cry_internal here, but only a trace, since
         * this is a typical case. It will occur for every directory
         * without a password file. */
        DEBUG_TRACE("fopen(%s): %s", name, strerror(ERRNO));
#endif
      }
    }
  }
}
#endif /* NO_FILESYSTEMS */


/* Parsed Authorization header */
struct ah {
  char *user;
  int type;             /* 1 = basic, 2 = digest */
  char *plain_password; /* Basic only */
  char *uri, *cnonce, *response, *qop, *nc, *nonce; /* Digest only */
};


/* Return 1 on success. Always initializes the ah structure. */
static int
parse_auth_header(struct mg_connection *conn,
                  char *buf,
                  size_t buf_size,
                  struct ah *ah)
{
  char *name, *value, *s;
  const char *auth_header;
  uint64_t nonce;

  if (!ah || !conn) {
    return 0;
  }

  (void)memset(ah, 0, sizeof(*ah));
  auth_header = mg_get_header(conn, "Authorization");

  if (auth_header == NULL) {
    /* No Authorization header at all */
    return 0;
  }
  if (0 == mg_strncasecmp(auth_header, "Basic ", 6)) {
    /* Basic Auth (we never asked for this, but some client may send it) */
    char *split;
    const char *userpw_b64 = auth_header + 6;
    size_t userpw_b64_len = strlen(userpw_b64);
    size_t buf_len_r = buf_size;
    if (mg_base64_decode(
            userpw_b64, userpw_b64_len, (unsigned char *)buf, &buf_len_r)
        != -1) {
      return 0; /* decode error */
    }
    split = strchr(buf, ':');
    if (!split) {
      return 0; /* Format error */
    }

    /* Separate string at ':' */
    *split = 0;

    /* User name is before ':', Password is after ':'  */
    ah->user = buf;
    ah->type = 1;
    ah->plain_password = split + 1;

    return 1;

  } else if (0 == mg_strncasecmp(auth_header, "Digest ", 7)) {
    /* Digest Auth ... implemented below */
    ah->type = 2;

  } else {
    /* Unknown or invalid Auth method */
    return 0;
  }

  /* Make modifiable copy of the auth header */
  (void)mg_strlcpy(buf, auth_header + 7, buf_size);
  s = buf;

  /* Parse authorization header */
  for (;;) {
    /* Gobble initial spaces */
    while (isspace((unsigned char)*s)) {
      s++;
    }
    name = skip_quoted(&s, "=", " ", 0);
    /* Value is either quote-delimited, or ends at first comma or space.
     */
    if (s[0] == '\"') {
      s++;
      value = skip_quoted(&s, "\"", " ", '\\');
      if (s[0] == ',') {
        s++;
      }
    } else {
      value = skip_quoted(&s, ", ", " ", 0); /* IE uses commas, FF
                                              * uses spaces */
    }
    if (*name == '\0') {
      break;
    }

    if (!strcmp(name, "username")) {
      ah->user = value;
    } else if (!strcmp(name, "cnonce")) {
      ah->cnonce = value;
    } else if (!strcmp(name, "response")) {
      ah->response = value;
    } else if (!strcmp(name, "uri")) {
      ah->uri = value;
    } else if (!strcmp(name, "qop")) {
      ah->qop = value;
    } else if (!strcmp(name, "nc")) {
      ah->nc = value;
    } else if (!strcmp(name, "nonce")) {
      ah->nonce = value;
    }
  }

#if !defined(NO_NONCE_CHECK)
  /* Read the nonce from the response. */
  if (ah->nonce == NULL) {
    return 0;
  }
  s = NULL;
  nonce = strtoull(ah->nonce, &s, 10);
  if ((s == NULL) || (*s != 0)) {
    return 0;
  }

  /* Convert the nonce from the client to a number. */
  nonce ^= conn->dom_ctx->auth_nonce_mask;

  /* The converted number corresponds to the time the nounce has been
   * created. This should not be earlier than the server start. */
  /* Server side nonce check is valuable in all situations but one:
   * if the server restarts frequently, but the client should not see
   * that, so the server should accept nonces from previous starts. */
  /* However, the reasonable default is to not accept a nonce from a
   * previous start, so if anyone changed the access rights between
   * two restarts, a new login is required. */
  if (nonce < (uint64_t)conn->phys_ctx->start_time) {
    /* nonce is from a previous start of the server and no longer valid
     * (replay attack?) */
    return 0;
  }
  /* Check if the nonce is too high, so it has not (yet) been used by the
   * server. */
  if (nonce >= ((uint64_t)conn->phys_ctx->start_time
                + conn->dom_ctx->nonce_count)) {
    return 0;
  }
#else
  (void)nonce;
#endif

  return (ah->user != NULL);
}


static const char *
mg_fgets(char *buf, size_t size, struct mg_file *filep)
{
  if (!filep) {
    return NULL;
  }

  if (filep->access.fp != NULL) {
    return fgets(buf, (int)size, filep->access.fp);
  } else {
    return NULL;
  }
}

/* Define the initial recursion depth for procesesing htpasswd files that
 * include other htpasswd
 * (or even the same) files.  It is not difficult to provide a file or files
 * s.t. they force civetweb
 * to infinitely recurse and then crash.
 */
#define INITIAL_DEPTH 9
#if INITIAL_DEPTH <= 0
#error Bad INITIAL_DEPTH for recursion, set to at least 1
#endif

#if !defined(NO_FILESYSTEMS)
struct read_auth_file_struct {
  struct mg_connection *conn;
  struct ah ah;
  const char *domain;
  char buf[256 + 256 + 40];
  const char *f_user;
  const char *f_domain;
  const char *f_ha1;
};


static int
read_auth_file(struct mg_file *filep,
               struct read_auth_file_struct *workdata,
               int depth)
{
  int is_authorized = 0;
  struct mg_file fp;
  size_t l;

  if (!filep || !workdata || (0 == depth)) {
    return 0;
  }

  /* Loop over passwords file */
  while (mg_fgets(workdata->buf, sizeof(workdata->buf), filep) != NULL) {
    l = strlen(workdata->buf);
    while (l > 0) {
      if (isspace((unsigned char)workdata->buf[l - 1])
          || iscntrl((unsigned char)workdata->buf[l - 1])) {
        l--;
        workdata->buf[l] = 0;
      } else
        break;
    }
    if (l < 1) {
      continue;
    }

    workdata->f_user = workdata->buf;

    if (workdata->f_user[0] == ':') {
      /* user names may not contain a ':' and may not be empty,
       * so lines starting with ':' may be used for a special purpose
       */
      if (workdata->f_user[1] == '#') {
        /* :# is a comment */
        continue;
      } else if (!strncmp(workdata->f_user + 1, "include=", 8)) {
        if (mg_fopen(workdata->conn,
                     workdata->f_user + 9,
                     MG_FOPEN_MODE_READ,
                     &fp)) {
          is_authorized = read_auth_file(&fp, workdata, depth - 1);
          (void)mg_fclose(
              &fp.access); /* ignore error on read only file */

          /* No need to continue processing files once we have a
           * match, since nothing will reset it back
           * to 0.
           */
          if (is_authorized) {
            return is_authorized;
          }
        } else {
          mg_cry_internal(workdata->conn,
                          "%s: cannot open authorization file: %s",
                          __func__,
                          workdata->buf);
        }
        continue;
      }
      /* everything is invalid for the moment (might change in the
       * future) */
      mg_cry_internal(workdata->conn,
                      "%s: syntax error in authorization file: %s",
                      __func__,
                      workdata->buf);
      continue;
    }

    workdata->f_domain = strchr(workdata->f_user, ':');
    if (workdata->f_domain == NULL) {
      mg_cry_internal(workdata->conn,
                      "%s: syntax error in authorization file: %s",
                      __func__,
                      workdata->buf);
      continue;
    }
    *(char *)(workdata->f_domain) = 0;
    (workdata->f_domain)++;

    workdata->f_ha1 = strchr(workdata->f_domain, ':');
    if (workdata->f_ha1 == NULL) {
      mg_cry_internal(workdata->conn,
                      "%s: syntax error in authorization file: %s",
                      __func__,
                      workdata->buf);
      continue;
    }
    *(char *)(workdata->f_ha1) = 0;
    (workdata->f_ha1)++;

    if (!strcmp(workdata->ah.user, workdata->f_user)
        && !strcmp(workdata->domain, workdata->f_domain)) {
      switch (workdata->ah.type) {
      case 1: /* Basic */
      {
        char md5[33];
        mg_md5(md5,
               workdata->f_user,
               ":",
               workdata->domain,
               ":",
               workdata->ah.plain_password,
               NULL);
        return 0 == memcmp(workdata->f_ha1, md5, 33);
      }
      case 2: /* Digest */
        return check_password_digest(
            workdata->conn->request_info.request_method,
            workdata->f_ha1,
            workdata->ah.uri,
            workdata->ah.nonce,
            workdata->ah.nc,
            workdata->ah.cnonce,
            workdata->ah.qop,
            workdata->ah.response);
      default: /* None/Other/Unknown */
        return 0;
      }
    }
  }

  return is_authorized;
}


/* Authorize against the opened passwords file. Return 1 if authorized. */
static int
authorize(struct mg_connection *conn, struct mg_file *filep, const char *realm)
{
  struct read_auth_file_struct workdata;
  char buf[MG_BUF_LEN];

  if (!conn || !conn->dom_ctx) {
    return 0;
  }

  memset(&workdata, 0, sizeof(workdata));
  workdata.conn = conn;

  if (!parse_auth_header(conn, buf, sizeof(buf), &workdata.ah)) {
    return 0;
  }

  /* CGI needs it as REMOTE_USER */
  conn->request_info.remote_user =
      mg_strdup_ctx(workdata.ah.user, conn->phys_ctx);

  if (realm) {
    workdata.domain = realm;
  } else {
    workdata.domain = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
  }

  return read_auth_file(filep, &workdata, INITIAL_DEPTH);
}


/* Public function to check http digest authentication header */
CIVETWEB_API int
mg_check_digest_access_authentication(struct mg_connection *conn,
                                      const char *realm,
                                      const char *filename)
{
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  int auth;

  if (!conn || !filename) {
    return -1;
  }
  if (!mg_fopen(conn, filename, MG_FOPEN_MODE_READ, &file)) {
    return -2;
  }

  auth = authorize(conn, &file, realm);

  mg_fclose(&file.access);

  return auth;
}
#endif /* NO_FILESYSTEMS */


/* Return 1 if request is authorised, 0 otherwise. */
static int
check_authorization(struct mg_connection *conn, const char *path)
{
#if !defined(NO_FILESYSTEMS)
  char fname[UTF8_PATH_MAX];
  struct vec uri_vec, filename_vec;
  const char *list;
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  int authorized = 1, truncated;

  if (!conn || !conn->dom_ctx) {
    return 0;
  }

  list = conn->dom_ctx->config[PROTECT_URI];
  while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
    if (!memcmp(conn->request_info.local_uri, uri_vec.ptr, uri_vec.len)) {
      mg_snprintf(conn,
                  &truncated,
                  fname,
                  sizeof(fname),
                  "%.*s",
                  (int)filename_vec.len,
                  filename_vec.ptr);

      if (truncated
          || !mg_fopen(conn, fname, MG_FOPEN_MODE_READ, &file)) {
        mg_cry_internal(conn,
                        "%s: cannot open %s: %s",
                        __func__,
                        fname,
                        strerror(errno));
      }
      break;
    }
  }

  if (!is_file_opened(&file.access)) {
    open_auth_file(conn, path, &file);
  }

  if (is_file_opened(&file.access)) {
    authorized = authorize(conn, &file, NULL);
    (void)mg_fclose(&file.access); /* ignore error on read only file */
  }

  return authorized;
#else
  (void)conn;
  (void)path;
  return 1;
#endif /* NO_FILESYSTEMS */
}


/* Internal function. Assumes conn is valid */
static void
send_authorization_request(struct mg_connection *conn, const char *realm)
{
  uint64_t nonce = (uint64_t)(conn->phys_ctx->start_time);
  int trunc = 0;
  char buf[128];

  if (!realm) {
    realm = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
  }

  mg_lock_context(conn->phys_ctx);
  nonce += conn->dom_ctx->nonce_count;
  ++conn->dom_ctx->nonce_count;
  mg_unlock_context(conn->phys_ctx);

  nonce ^= conn->dom_ctx->auth_nonce_mask;
  conn->must_close = 1;

  /* Create 401 response */
  mg_response_header_start(conn, 401);
  send_no_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn, "Content-Length", "0", -1);

  /* Content for "WWW-Authenticate" header */
  mg_snprintf(conn,
              &trunc,
              buf,
              sizeof(buf),
              "Digest qop=\"auth\", realm=\"%s\", "
              "nonce=\"%" UINT64_FMT "\"",
              realm,
              nonce);

  if (!trunc) {
    /* !trunc should always be true */
    mg_response_header_add(conn, "WWW-Authenticate", buf, -1);
  }

  /* Send all headers */
  mg_response_header_send(conn);
}


/* Interface function. Parameters are provided by the user, so do
 * at least some basic checks.
 */
CIVETWEB_API int
mg_send_digest_access_authentication_request(struct mg_connection *conn,
                                             const char *realm)
{
  if (conn && conn->dom_ctx) {
    send_authorization_request(conn, realm);
    return 0;
  }
  return -1;
}


#if !defined(NO_FILES)
static int
is_authorized_for_put(struct mg_connection *conn)
{
  int ret = 0;

  if (conn) {
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    const char *passfile = conn->dom_ctx->config[PUT_DELETE_PASSWORDS_FILE];

    if (passfile != NULL
        && mg_fopen(conn, passfile, MG_FOPEN_MODE_READ, &file)) {
      ret = authorize(conn, &file, NULL);
      (void)mg_fclose(&file.access); /* ignore error on read only file */
    }
  }

  DEBUG_TRACE("file write authorization: %i", ret);
  return ret;
}
#endif


CIVETWEB_API int
mg_modify_passwords_file_ha1(const char *fname,
                             const char *domain,
                             const char *user,
                             const char *ha1)
{
  int found = 0, i, result = 1;
  char line[512], u[256], d[256], h[256];
  struct stat st = {0};
  FILE *fp = NULL;
  char *temp_file = NULL;
  int temp_file_offs = 0;

  /* Regard empty password as no password - remove user record. */
  if ((ha1 != NULL) && (ha1[0] == '\0')) {
    ha1 = NULL;
  }

  /* Other arguments must not be empty */
  if ((fname == NULL) || (domain == NULL) || (user == NULL)) {
    return 0;
  }

  /* Using the given file format, user name and domain must not contain
   * the ':' character */
  if (strchr(user, ':') != NULL) {
    return 0;
  }
  if (strchr(domain, ':') != NULL) {
    return 0;
  }

  /* Do not allow control characters like newline in user name and domain.
   * Do not allow excessively long names either. */
  for (i = 0; ((i < 255) && (user[i] != 0)); i++) {
    if (iscntrl((unsigned char)user[i])) {
      return 0;
    }
  }
  if (user[i]) {
    return 0; /* user name too long */
  }
  for (i = 0; ((i < 255) && (domain[i] != 0)); i++) {
    if (iscntrl((unsigned char)domain[i])) {
      return 0;
    }
  }
  if (domain[i]) {
    return 0; /* domain name too long */
  }

  /* The maximum length of the path to the password file is limited */
  if (strlen(fname) >= UTF8_PATH_MAX) {
    return 0;
  }

  /* Check if the file exists, and get file size */
  if (0 == stat(fname, &st)) {
    int temp_buf_len = (int)st.st_size + 1024;

    /* Allocate memory (instead of using a temporary file) */
    temp_file = (char *)mg_calloc(temp_buf_len, 1);
    if (!temp_file) {
      /* Out of memory */
      return 0;
    }

    /* File exists. Read it into a memory buffer. */
    fp = fopen(fname, "r");
    if (fp == NULL) {
      /* Cannot read file. No permission? */
      mg_free(temp_file);
      return 0;
    }

    /* Read content and store in memory */
    while ((fgets(line, sizeof(line), fp) != NULL)
           && ((temp_file_offs + 600) < temp_buf_len)) {
      /* file format is "user:domain:hash\n" */
      if (sscanf(line, "%255[^:]:%255[^:]:%255s", u, d, h) != 3) {
        continue;
      }
      u[255] = 0;
      d[255] = 0;
      h[255] = 0;

      if (!strcmp(u, user) && !strcmp(d, domain)) {
        /* Found the user: change the password hash or drop the user
         */
        if ((ha1 != NULL) && (!found)) {
          i = sprintf(temp_file + temp_file_offs,
                      "%s:%s:%s\n",
                      user,
                      domain,
                      ha1);
          if (i < 1) {
            fclose(fp);
            mg_free(temp_file);
            return 0;
          }
          temp_file_offs += i;
        }
        found = 1;
      } else {
        /* Copy existing user, including password hash */
        i = sprintf(temp_file + temp_file_offs, "%s:%s:%s\n", u, d, h);
        if (i < 1) {
          fclose(fp);
          mg_free(temp_file);
          return 0;
        }
        temp_file_offs += i;
      }
    }
    fclose(fp);
  }

  /* Create new file */
  fp = fopen(fname, "w");
  if (!fp) {
    mg_free(temp_file);
    return 0;
  }

#if !defined(_WIN32)
  /* On Linux & co., restrict file read/write permissions to the owner */
  if (fchmod(fileno(fp), S_IRUSR | S_IWUSR) != 0) {
    result = 0;
  }
#endif

  if ((temp_file != NULL) && (temp_file_offs > 0)) {
    /* Store buffered content of old file */
    if (fwrite(temp_file, 1, temp_file_offs, fp)
        != (size_t)temp_file_offs) {
      result = 0;
    }
  }

  /* If new user, just add it */
  if ((ha1 != NULL) && (!found)) {
    if (fprintf(fp, "%s:%s:%s\n", user, domain, ha1) < 6) {
      result = 0;
    }
  }

  /* All data written */
  if (fclose(fp) != 0) {
    result = 0;
  }

  mg_free(temp_file);
  return result;
}


CIVETWEB_API int
mg_modify_passwords_file(const char *fname,
                         const char *domain,
                         const char *user,
                         const char *pass)
{
  char ha1buf[33];
  if ((fname == NULL) || (domain == NULL) || (user == NULL)) {
    return 0;
  }
  if ((pass == NULL) || (pass[0] == 0)) {
    return mg_modify_passwords_file_ha1(fname, domain, user, NULL);
  }

  mg_md5(ha1buf, user, ":", domain, ":", pass, NULL);
  return mg_modify_passwords_file_ha1(fname, domain, user, ha1buf);
}


static int
is_valid_port(unsigned long port)
{
  return (port <= 0xffff);
}


static int
mg_inet_pton(int af, const char *src, void *dst, size_t dstlen, int resolve_src)
{
  struct addrinfo hints, *res, *ressave;
  int func_ret = 0;
  int gai_ret;

  memset(&hints, 0, sizeof(struct addrinfo));
  hints.ai_family = af;
  if (!resolve_src) {
    hints.ai_flags = AI_NUMERICHOST;
  }

  gai_ret = getaddrinfo(src, NULL, &hints, &res);
  if (gai_ret != 0) {
    /* gai_strerror could be used to convert gai_ret to a string */
    /* POSIX return values: see
     * http://pubs.opengroup.org/onlinepubs/9699919799/functions/freeaddrinfo.html
     */
    /* Windows return values: see
     * https://msdn.microsoft.com/en-us/library/windows/desktop/ms738520%28v=vs.85%29.aspx
     */
    return 0;
  }

  ressave = res;

  while (res) {
    if ((dstlen >= (size_t)res->ai_addrlen)
        && (res->ai_addr->sa_family == af)) {
      memcpy(dst, res->ai_addr, res->ai_addrlen);
      func_ret = 1;
    }
    res = res->ai_next;
  }

  freeaddrinfo(ressave);
  return func_ret;
}


static int
connect_socket(
    struct mg_context *ctx /* may be NULL */,
    const char *host,
    int port,    /* 1..65535, or -99 for domain sockets (may be changed) */
    int use_ssl, /* 0 or 1 */
    struct mg_error_data *error,
    SOCKET *sock /* output: socket, must not be NULL */,
    union usa *sa /* output: socket address, must not be NULL  */
)
{
  int ip_ver = 0;
  int conn_ret = -1;
  int sockerr = 0;
  *sock = INVALID_SOCKET;
  memset(sa, 0, sizeof(*sa));

  if (host == NULL) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "NULL host");
    }
    return 0;
  }

#if defined(USE_X_DOM_SOCKET)
  if (port == -99) {
    /* Unix domain socket */
    size_t hostlen = strlen(host);
    if (hostlen >= sizeof(sa->sun.sun_path)) {
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for ebuf */
                    error->text,
                    error->text_buffer_size,
                    "%s",
                    "host length exceeds limit");
      }
      return 0;
    }
  } else
#endif
      if ((port <= 0) || !is_valid_port((unsigned)port)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "invalid port");
    }
    return 0;
  }

#if !defined(NO_SSL) && !defined(USE_MBEDTLS) && !defined(NO_SSL_DL)
#if defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0)
  if (use_ssl && (TLS_client_method == NULL)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_LIBRARY_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "SSL is not initialized");
    }
    return 0;
  }
#else
  if (use_ssl && (SSLv23_client_method == NULL)) {
    if (error != 0) {
      error->code = MG_ERROR_DATA_CODE_INIT_LIBRARY_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "SSL is not initialized");
    }
    return 0;
  }
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0*/
#else
  (void)use_ssl;
#endif /* NO SSL */

#if defined(USE_X_DOM_SOCKET)
  if (port == -99) {
    size_t hostlen = strlen(host);
    /* check (hostlen < sizeof(sun.sun_path)) already passed above */
    ip_ver = -99;
    sa->sun.sun_family = AF_UNIX;
    memset(sa->sun.sun_path, 0, sizeof(sa->sun.sun_path));
    memcpy(sa->sun.sun_path, host, hostlen);
  } else
#endif
      if (mg_inet_pton(AF_INET, host, &sa->sin, sizeof(sa->sin), 1)) {
    sa->sin.sin_port = htons((uint16_t)port);
    ip_ver = 4;
#if defined(USE_IPV6)
  } else if (mg_inet_pton(AF_INET6, host, &sa->sin6, sizeof(sa->sin6), 1)) {
    sa->sin6.sin6_port = htons((uint16_t)port);
    ip_ver = 6;
  } else if (host[0] == '[') {
    /* While getaddrinfo on Windows will work with [::1],
     * getaddrinfo on Linux only works with ::1 (without []). */
    size_t l = strlen(host + 1);
    char *h = (l > 1) ? mg_strdup_ctx(host + 1, ctx) : NULL;
    if (h) {
      h[l - 1] = 0;
      if (mg_inet_pton(AF_INET6, h, &sa->sin6, sizeof(sa->sin6), 0)) {
        sa->sin6.sin6_port = htons((uint16_t)port);
        ip_ver = 6;
      }
      mg_free(h);
    }
#endif
  }

  if (ip_ver == 0) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_HOST_NOT_FOUND;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "host not found");
    }
    return 0;
  }

  if (ip_ver == 4) {
    *sock = socket(PF_INET, SOCK_STREAM, 0);
  }
#if defined(USE_IPV6)
  else if (ip_ver == 6) {
    *sock = socket(PF_INET6, SOCK_STREAM, 0);
  }
#endif
#if defined(USE_X_DOM_SOCKET)
  else if (ip_ver == -99) {
    *sock = socket(AF_UNIX, SOCK_STREAM, 0);
  }
#endif

  if (*sock == INVALID_SOCKET) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OS_ERROR;
      error->code_sub = ERRNO;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "socket(): %s",
                  strerror(ERRNO));
    }
    return 0;
  }

  if (0 != set_non_blocking_mode(*sock)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OS_ERROR;
      error->code_sub = ERRNO;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "Cannot set socket to non-blocking: %s",
                  strerror(ERRNO));
    }
    closesocket(*sock);
    *sock = INVALID_SOCKET;
    return 0;
  }

  set_close_on_exec(*sock, NULL, ctx);

  if (ip_ver == 4) {
    /* connected with IPv4 */
    conn_ret = connect(*sock,
                       (struct sockaddr *)((void *)&sa->sin),
                       sizeof(sa->sin));
  }
#if defined(USE_IPV6)
  else if (ip_ver == 6) {
    /* connected with IPv6 */
    conn_ret = connect(*sock,
                       (struct sockaddr *)((void *)&sa->sin6),
                       sizeof(sa->sin6));
  }
#endif
#if defined(USE_X_DOM_SOCKET)
  else if (ip_ver == -99) {
    /* connected to domain socket */
    conn_ret = connect(*sock,
                       (struct sockaddr *)((void *)&sa->sun),
                       sizeof(sa->sun));
  }
#endif

  if (conn_ret != 0) {
    sockerr = ERRNO;
  }

#if defined(_WIN32)
  if ((conn_ret != 0) && (sockerr == WSAEWOULDBLOCK)) {
#else
  if ((conn_ret != 0) && (sockerr == EINPROGRESS)) {
#endif
    /* Data for getsockopt */
    void *psockerr = &sockerr;
    int ret;

#if defined(_WIN32)
    int len = (int)sizeof(sockerr);
#else
    socklen_t len = (socklen_t)sizeof(sockerr);
#endif

    /* Data for poll */
    struct mg_pollfd pfd[1];
    int pollres;
    int ms_wait = 10000; /* 10 second timeout */
    stop_flag_t nonstop;
    STOP_FLAG_ASSIGN(&nonstop, 0);

    /* For a non-blocking socket, the connect sequence is:
     * 1) call connect (will not block)
     * 2) wait until the socket is ready for writing (select or poll)
     * 3) check connection state with getsockopt
     */
    pfd[0].fd = *sock;
    pfd[0].events = POLLOUT;
    pollres = mg_poll(pfd, 1, ms_wait, ctx ? &(ctx->stop_flag) : &nonstop);

    if (pollres != 1) {
      /* Not connected */
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_CONNECT_TIMEOUT;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for ebuf */
                    error->text,
                    error->text_buffer_size,
                    "connect(%s:%d): timeout",
                    host,
                    port);
      }
      closesocket(*sock);
      *sock = INVALID_SOCKET;
      return 0;
    }

#if defined(_WIN32)
    ret = getsockopt(*sock, SOL_SOCKET, SO_ERROR, (char *)psockerr, &len);
#else
    ret = getsockopt(*sock, SOL_SOCKET, SO_ERROR, psockerr, &len);
#endif

    if ((ret == 0) && (sockerr == 0)) {
      conn_ret = 0;
    }
  }

  if (conn_ret != 0) {
    /* Not connected */
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_CONNECT_FAILED;
      error->code_sub = ERRNO;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "connect(%s:%d): error %s",
                  host,
                  port,
                  strerror(sockerr));
    }
    closesocket(*sock);
    *sock = INVALID_SOCKET;
    return 0;
  }

  return 1;
}


CIVETWEB_API int
mg_url_encode(const char *src, char *dst, size_t dst_len)
{
  static const char *dont_escape = "._-$,;~()";
  static const char *hex = "0123456789abcdef";
  char *pos = dst;
  const char *end = dst + dst_len - 1;

  for (; ((*src != '\0') && (pos < end)); src++, pos++) {
    if (isalnum((unsigned char)*src)
        || (strchr(dont_escape, *src) != NULL)) {
      *pos = *src;
    } else if (pos + 2 < end) {
      pos[0] = '%';
      pos[1] = hex[(unsigned char)*src >> 4];
      pos[2] = hex[(unsigned char)*src & 0xf];
      pos += 2;
    } else {
      break;
    }
  }

  *pos = '\0';
  return (*src == '\0') ? (int)(pos - dst) : -1;
}

/* Return 0 on success, non-zero if an error occurs. */

static int
print_dir_entry(struct mg_connection *conn, struct de *de)
{
  size_t namesize, escsize, i;
  char *href, *esc, *p;
  char size[64], mod[64];
#if defined(REENTRANT_TIME)
  struct tm _tm;
  struct tm *tm = &_tm;
#else
  struct tm *tm;
#endif

  /* Estimate worst case size for encoding and escaping */
  namesize = strlen(de->file_name) + 1;
  escsize = de->file_name[strcspn(de->file_name, "&<>")] ? namesize * 5 : 0;
  href = (char *)mg_malloc(namesize * 3 + escsize);
  if (href == NULL) {
    return -1;
  }
  mg_url_encode(de->file_name, href, namesize * 3);
  esc = NULL;
  if (escsize > 0) {
    /* HTML escaping needed */
    esc = href + namesize * 3;
    for (i = 0, p = esc; de->file_name[i]; i++, p += strlen(p)) {
      mg_strlcpy(p, de->file_name + i, 2);
      if (*p == '&') {
        strcpy(p, "&amp;");
      } else if (*p == '<') {
        strcpy(p, "&lt;");
      } else if (*p == '>') {
        strcpy(p, "&gt;");
      }
    }
  }

  if (de->file.is_directory) {
    mg_snprintf(conn,
                NULL, /* Buffer is big enough */
                size,
                sizeof(size),
                "%s",
                "[DIRECTORY]");
  } else {
    /* We use (signed) cast below because MSVC 6 compiler cannot
     * convert unsigned __int64 to double. Sigh. */
    if (de->file.size < 1024) {
      mg_snprintf(conn,
                  NULL, /* Buffer is big enough */
                  size,
                  sizeof(size),
                  "%d",
                  (int)de->file.size);
    } else if (de->file.size < 0x100000) {
      mg_snprintf(conn,
                  NULL, /* Buffer is big enough */
                  size,
                  sizeof(size),
                  "%.1fk",
                  (double)de->file.size / 1024.0);
    } else if (de->file.size < 0x40000000) {
      mg_snprintf(conn,
                  NULL, /* Buffer is big enough */
                  size,
                  sizeof(size),
                  "%.1fM",
                  (double)de->file.size / 1048576);
    } else {
      mg_snprintf(conn,
                  NULL, /* Buffer is big enough */
                  size,
                  sizeof(size),
                  "%.1fG",
                  (double)de->file.size / 1073741824);
    }
  }

  /* Note: mg_snprintf will not cause a buffer overflow above.
   * So, string truncation checks are not required here. */

#if defined(REENTRANT_TIME)
  localtime_r(&de->file.last_modified, tm);
#else
  tm = localtime(&de->file.last_modified);
#endif
  if (tm != NULL) {
    strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M", tm);
  } else {
    mg_strlcpy(mod, "01-Jan-1970 00:00", sizeof(mod));
  }
  mg_printf(conn,
            "<tr><td><a href=\"%s%s\">%s%s</a></td>"
            "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
            href,
            de->file.is_directory ? "/" : "",
            esc ? esc : de->file_name,
            de->file.is_directory ? "/" : "",
            mod,
            size);
  mg_free(href);
  return 0;
}


/* This function is called from send_directory() and used for
 * sorting directory entries by size, name, or modification time. */
static int
compare_dir_entries(const void *p1, const void *p2, void *arg)
{
  const char *query_string = (const char *)(arg != NULL ? arg : "");
  if (p1 && p2) {
    const struct de *a = (const struct de *)p1, *b = (const struct de *)p2;
    int cmp_result = 0;

    if ((query_string == NULL) || (query_string[0] == '\0')) {
      query_string = "n";
    }

    /* Sort Directories vs Files */
    if (a->file.is_directory && !b->file.is_directory) {
      return -1; /* Always put directories on top */
    } else if (!a->file.is_directory && b->file.is_directory) {
      return 1; /* Always put directories on top */
    }

    /* Sort by size or date */
    if (*query_string == 's') {
      cmp_result = (a->file.size == b->file.size)
                       ? 0
                       : ((a->file.size > b->file.size) ? 1 : -1);
    } else if (*query_string == 'd') {
      cmp_result =
          (a->file.last_modified == b->file.last_modified)
              ? 0
              : ((a->file.last_modified > b->file.last_modified) ? 1
                                                                 : -1);
    }

    /* Sort by name:
     * if (*query_string == 'n')  ...
     * but also sort files of same size/date by name as secondary criterion.
     */
    if (cmp_result == 0) {
      cmp_result = strcmp(a->file_name, b->file_name);
    }

    /* For descending order, invert result */
    return (query_string[1] == 'd') ? -cmp_result : cmp_result;
  }
  return 0;
}


static int
must_hide_file(struct mg_connection *conn, const char *path)
{
  if (conn && conn->dom_ctx) {
    const char *pw_pattern = "**" PASSWORDS_FILE_NAME "$";
    const char *pattern = conn->dom_ctx->config[HIDE_FILES];
    return (match_prefix_strlen(pw_pattern, path) > 0)
           || (match_prefix_strlen(pattern, path) > 0);
  }
  return 0;
}


#if !defined(NO_FILESYSTEMS)
static int
scan_directory(struct mg_connection *conn,
               const char *dir,
               void *data,
               int (*cb)(struct de *, void *))
{
  char path[UTF8_PATH_MAX];
  struct dirent *dp;
  DIR *dirp;
  struct de de;
  int truncated;

  if ((dirp = mg_opendir(conn, dir)) == NULL) {
    return 0;
  } else {

    while ((dp = mg_readdir(dirp)) != NULL) {
      /* Do not show current dir and hidden files */
      if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")
          || must_hide_file(conn, dp->d_name)) {
        continue;
      }

      mg_snprintf(
          conn, &truncated, path, sizeof(path), "%s/%s", dir, dp->d_name);

      /* If we don't memset stat structure to zero, mtime will have
       * garbage and strftime() will segfault later on in
       * print_dir_entry(). memset is required only if mg_stat()
       * fails. For more details, see
       * http://code.google.com/p/mongoose/issues/detail?id=79 */
      memset(&de.file, 0, sizeof(de.file));

      if (truncated) {
        /* If the path is not complete, skip processing. */
        continue;
      }

      if (!mg_stat(conn, path, &de.file)) {
        mg_cry_internal(conn,
                        "%s: mg_stat(%s) failed: %s",
                        __func__,
                        path,
                        strerror(ERRNO));
      }
      de.file_name = dp->d_name;
      if (cb(&de, data)) {
        /* stopped */
        break;
      }
    }
    (void)mg_closedir(dirp);
  }
  return 1;
}
#endif /* NO_FILESYSTEMS */


#if !defined(NO_FILES)
static int
remove_directory(struct mg_connection *conn, const char *dir)
{
  char path[UTF8_PATH_MAX];
  struct dirent *dp;
  DIR *dirp;
  struct de de;
  int truncated;
  int ok = 1;

  if ((dirp = mg_opendir(conn, dir)) == NULL) {
    return 0;
  } else {

    while ((dp = mg_readdir(dirp)) != NULL) {
      /* Do not show current dir (but show hidden files as they will
       * also be removed) */
      if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) {
        continue;
      }

      mg_snprintf(
          conn, &truncated, path, sizeof(path), "%s/%s", dir, dp->d_name);

      /* If we don't memset stat structure to zero, mtime will have
       * garbage and strftime() will segfault later on in
       * print_dir_entry(). memset is required only if mg_stat()
       * fails. For more details, see
       * http://code.google.com/p/mongoose/issues/detail?id=79 */
      memset(&de.file, 0, sizeof(de.file));

      if (truncated) {
        /* Do not delete anything shorter */
        ok = 0;
        continue;
      }

      if (!mg_stat(conn, path, &de.file)) {
        mg_cry_internal(conn,
                        "%s: mg_stat(%s) failed: %s",
                        __func__,
                        path,
                        strerror(ERRNO));
        ok = 0;
      }

      if (de.file.is_directory) {
        if (remove_directory(conn, path) == 0) {
          ok = 0;
        }
      } else {
        /* This will fail file is the file is in memory */
        if (mg_remove(conn, path) == 0) {
          ok = 0;
        }
      }
    }
    (void)mg_closedir(dirp);

    IGNORE_UNUSED_RESULT(rmdir(dir));
  }

  return ok;
}
#endif


struct dir_scan_data {
  struct de *entries;
  size_t num_entries;
  size_t arr_size;
};


#if !defined(NO_FILESYSTEMS)
static int
dir_scan_callback(struct de *de, void *data)
{
  struct dir_scan_data *dsd = (struct dir_scan_data *)data;
  struct de *entries = dsd->entries;

  if ((entries == NULL) || (dsd->num_entries >= dsd->arr_size)) {
    /* Here "entries" is a temporary pointer and can be replaced,
     * "dsd->entries" is the original pointer */
    entries =
        (struct de *)mg_realloc(entries,
                                dsd->arr_size * 2 * sizeof(entries[0]));
    if (entries == NULL) {
      /* stop scan */
      return 1;
    }
    dsd->entries = entries;
    dsd->arr_size *= 2;
  }
  entries[dsd->num_entries].file_name = mg_strdup(de->file_name);
  if (entries[dsd->num_entries].file_name == NULL) {
    /* stop scan */
    return 1;
  }
  entries[dsd->num_entries].file = de->file;
  dsd->num_entries++;

  return 0;
}


static void
handle_directory_request(struct mg_connection *conn, const char *dir)
{
  size_t i;
  int sort_direction;
  struct dir_scan_data data = {NULL, 0, 128};
  char date[64], *esc, *p;
  const char *title;
  time_t curtime = time(NULL);

  if (!conn) {
    return;
  }

  if (!scan_directory(conn, dir, &data, dir_scan_callback)) {
    mg_send_http_error(conn,
                       500,
                       "Error: Cannot open directory\nopendir(%s): %s",
                       dir,
                       strerror(ERRNO));
    return;
  }

  gmt_time_string(date, sizeof(date), &curtime);

  esc = NULL;
  title = conn->request_info.local_uri;
  if (title[strcspn(title, "&<>")]) {
    /* HTML escaping needed */
    esc = (char *)mg_malloc(strlen(title) * 5 + 1);
    if (esc) {
      for (i = 0, p = esc; title[i]; i++, p += strlen(p)) {
        mg_strlcpy(p, title + i, 2);
        if (*p == '&') {
          strcpy(p, "&amp;");
        } else if (*p == '<') {
          strcpy(p, "&lt;");
        } else if (*p == '>') {
          strcpy(p, "&gt;");
        }
      }
    } else {
      title = "";
    }
  }

  sort_direction = ((conn->request_info.query_string != NULL)
                    && (conn->request_info.query_string[0] != '\0')
                    && (conn->request_info.query_string[1] == 'd'))
                       ? 'a'
                       : 'd';

  conn->must_close = 1;

  /* Create 200 OK response */
  mg_response_header_start(conn, 200);
  send_static_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn,
                         "Content-Type",
                         "text/html; charset=utf-8",
                         -1);

  /* Send all headers */
  mg_response_header_send(conn);

  /* Body */
  mg_printf(conn,
            "<html><head><title>Index of %s</title>"
            "<style>th {text-align: left;}</style></head>"
            "<body><h1>Index of %s</h1><pre><table cellpadding=\"0\">"
            "<tr><th><a href=\"?n%c\">Name</a></th>"
            "<th><a href=\"?d%c\">Modified</a></th>"
            "<th><a href=\"?s%c\">Size</a></th></tr>"
            "<tr><td colspan=\"3\"><hr></td></tr>",
            esc ? esc : title,
            esc ? esc : title,
            sort_direction,
            sort_direction,
            sort_direction);
  mg_free(esc);

  /* Print first entry - link to a parent directory */
  mg_printf(conn,
            "<tr><td><a href=\"%s\">%s</a></td>"
            "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
            "..",
            "Parent directory",
            "-",
            "-");

  /* Sort and print directory entries */
  if (data.entries != NULL) {
    mg_sort(data.entries,
            data.num_entries,
            sizeof(data.entries[0]),
            compare_dir_entries,
            (void *)conn->request_info.query_string);
    for (i = 0; i < data.num_entries; i++) {
      print_dir_entry(conn, &data.entries[i]);
      mg_free(data.entries[i].file_name);
    }
    mg_free(data.entries);
  }

  mg_printf(conn, "%s", "</table></pre></body></html>");
  conn->status_code = 200;
}
#endif /* NO_FILESYSTEMS */


/* Send len bytes from the opened file to the client. */
static void
send_file_data(struct mg_connection *conn,
               struct mg_file *filep,
               int64_t offset,
               int64_t len,
               int no_buffering)
{
  char buf[MG_BUF_LEN];
  int to_read, num_read, num_written;
  int64_t size;

  if (!filep || !conn) {
    return;
  }

  /* Sanity check the offset */
  size = (filep->stat.size > INT64_MAX) ? INT64_MAX
                                        : (int64_t)(filep->stat.size);
  offset = (offset < 0) ? 0 : ((offset > size) ? size : offset);

  if (len > 0 && filep->access.fp != NULL) {
    /* file stored on disk */
#if defined(__linux__)
    /* sendfile is only available for Linux */
    if ((conn->ssl == 0) && (conn->throttle == 0)
        && (!mg_strcasecmp(conn->dom_ctx->config[ALLOW_SENDFILE_CALL],
                           "yes"))) {
      off_t sf_offs = (off_t)offset;
      ssize_t sf_sent;
      int sf_file = fileno(filep->access.fp);
      int loop_cnt = 0;

      do {
        /* 2147479552 (0x7FFFF000) is a limit found by experiment on
         * 64 bit Linux (2^31 minus one memory page of 4k?). */
        size_t sf_tosend =
            (size_t)((len < 0x7FFFF000) ? len : 0x7FFFF000);
        sf_sent =
            sendfile(conn->client.sock, sf_file, &sf_offs, sf_tosend);
        if (sf_sent > 0) {
          len -= sf_sent;
          offset += sf_sent;
        } else if (loop_cnt == 0) {
          /* This file can not be sent using sendfile.
           * This might be the case for pseudo-files in the
           * /sys/ and /proc/ file system.
           * Use the regular user mode copy code instead. */
          break;
        } else if (sf_sent == 0) {
          /* No error, but 0 bytes sent. May be EOF? */
          return;
        }
        loop_cnt++;

      } while ((len > 0) && (sf_sent >= 0));

      if (sf_sent > 0) {
        return; /* OK */
      }

      /* sf_sent<0 means error, thus fall back to the classic way */
      /* This is always the case, if sf_file is not a "normal" file,
       * e.g., for sending data from the output of a CGI process. */
      offset = (int64_t)sf_offs;
    }
#endif
    if ((offset > 0) && (fseeko(filep->access.fp, offset, SEEK_SET) != 0)) {
      mg_cry_internal(conn,
                      "%s: fseeko() failed: %s",
                      __func__,
                      strerror(ERRNO));
      mg_send_http_error(
          conn,
          500,
          "%s",
          "Error: Unable to access file at requested position.");
    } else {
      while (len > 0) {
        /* Calculate how much to read from the file into the buffer. */
        /* If no_buffering is set, we should not wait until the
         * CGI->Server buffer is filled, but send everything
         * immediately. In theory buffering could be turned off using
         * setbuf(filep->access.fp, NULL);
         * setvbuf(filep->access.fp, NULL, _IONBF, 0);
         * but in practice this does not work. A "Linux only" solution
         * may be to use select(). The only portable way is to read byte
         * by byte, but this is quite inefficient from a performance
         * point of view. */
        to_read = no_buffering ? 1 : sizeof(buf);
        if ((int64_t)to_read > len) {
          to_read = (int)len;
        }

        /* Read from file, exit the loop on error */
        if ((num_read =
                 (int)fread(buf, 1, (size_t)to_read, filep->access.fp))
            <= 0) {
          break;
        }

        /* Send read bytes to the client, exit the loop on error */
        if ((num_written = mg_write(conn, buf, (size_t)num_read))
            != num_read) {
          break;
        }

        /* Both read and were successful, adjust counters */
        len -= num_written;
      }
    }
  }
}


static int
parse_range_header(const char *header, int64_t *a, int64_t *b)
{
  return sscanf(header,
                "bytes=%" INT64_FMT "-%" INT64_FMT,
                a,
                b); // NOLINT(cert-err34-c) 'sscanf' used to convert a string
                    // to an integer value, but function will not report
                    // conversion errors; consider using 'strtol' instead
}


static void
construct_etag(char *buf, size_t buf_len, const struct mg_file_stat *filestat)
{
  if ((filestat != NULL) && (buf != NULL)) {
    mg_snprintf(NULL,
                NULL, /* All calls to construct_etag use 64 byte buffer */
                buf,
                buf_len,
                "\"%lx.%" INT64_FMT "\"",
                (unsigned long)filestat->last_modified,
                filestat->size);
  }
}


static void
fclose_on_exec(struct mg_file_access *filep, struct mg_connection *conn)
{
  if (filep != NULL && filep->fp != NULL) {
#if defined(_WIN32)
    (void)conn; /* Unused. */
#else
    if (fcntl(fileno(filep->fp), F_SETFD, FD_CLOEXEC) != 0) {
      mg_cry_internal(conn,
                      "%s: fcntl(F_SETFD FD_CLOEXEC) failed: %s",
                      __func__,
                      strerror(ERRNO));
    }
#endif
  }
}


#if defined(USE_ZLIB)
#include "mod_zlib.inl"
#endif


#if !defined(NO_FILESYSTEMS)
static void
handle_static_file_request(struct mg_connection *conn,
                           const char *path,
                           struct mg_file *filep,
                           const char *mime_type,
                           const char *additional_headers)
{
  char lm[64], etag[64];
  char range[128]; /* large enough, so there will be no overflow */
  const char *range_hdr;
  int64_t cl, r1, r2;
  struct vec mime_vec;
  int n, truncated;
  char gz_path[UTF8_PATH_MAX];
  const char *encoding = 0;
  int is_head_request;

#if defined(USE_ZLIB)
  /* Compression is allowed, unless there is a reason not to use
   * compression. If the file is already compressed, too small or a
   * "range" request was made, on the fly compression is not possible. */
  int allow_on_the_fly_compression = 1;
#endif

  if ((conn == NULL) || (conn->dom_ctx == NULL) || (filep == NULL)) {
    return;
  }

  is_head_request = !strcmp(conn->request_info.request_method, "HEAD");

  if (mime_type == NULL) {
    get_mime_type(conn, path, &mime_vec);
  } else {
    mime_vec.ptr = mime_type;
    mime_vec.len = strlen(mime_type);
  }
  if (filep->stat.size > INT64_MAX) {
    mg_send_http_error(conn,
                       500,
                       "Error: File size is too large to send\n%" INT64_FMT,
                       filep->stat.size);
    return;
  }
  cl = (int64_t)filep->stat.size;
  conn->status_code = 200;
  range[0] = '\0';

#if defined(USE_ZLIB)
  /* if this file is in fact a pre-gzipped file, rewrite its filename
   * it's important to rewrite the filename after resolving
   * the mime type from it, to preserve the actual file's type */
  if (!conn->accept_gzip) {
    allow_on_the_fly_compression = 0;
  }
#endif

  /* Check if there is a range header */
  range_hdr = mg_get_header(conn, "Range");

  /* For gzipped files, add *.gz */
  if (filep->stat.is_gzipped) {
    mg_snprintf(conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", path);

    if (truncated) {
      mg_send_http_error(conn,
                         500,
                         "Error: Path of zipped file too long (%s)",
                         path);
      return;
    }

    path = gz_path;
    encoding = "gzip";

#if defined(USE_ZLIB)
    /* File is already compressed. No "on the fly" compression. */
    allow_on_the_fly_compression = 0;
#endif
  } else if ((conn->accept_gzip) && (range_hdr == NULL)
             && (filep->stat.size >= MG_FILE_COMPRESSION_SIZE_LIMIT)) {
    struct mg_file_stat file_stat;

    mg_snprintf(conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", path);

    if (!truncated && mg_stat(conn, gz_path, &file_stat)
        && !file_stat.is_directory) {
      file_stat.is_gzipped = 1;
      filep->stat = file_stat;
      cl = (int64_t)filep->stat.size;
      path = gz_path;
      encoding = "gzip";

#if defined(USE_ZLIB)
      /* File is already compressed. No "on the fly" compression. */
      allow_on_the_fly_compression = 0;
#endif
    }
  }

  if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, filep)) {
    mg_send_http_error(conn,
                       500,
                       "Error: Cannot open file\nfopen(%s): %s",
                       path,
                       strerror(ERRNO));
    return;
  }

  fclose_on_exec(&filep->access, conn);

  /* If "Range" request was made: parse header, send only selected part
   * of the file. */
  r1 = r2 = 0;
  if ((range_hdr != NULL)
      && ((n = parse_range_header(range_hdr, &r1, &r2)) > 0) && (r1 >= 0)
      && (r2 >= 0)) {
    /* actually, range requests don't play well with a pre-gzipped
     * file (since the range is specified in the uncompressed space) */
    if (filep->stat.is_gzipped) {
      mg_send_http_error(
          conn,
          416, /* 416 = Range Not Satisfiable */
          "%s",
          "Error: Range requests in gzipped files are not supported");
      (void)mg_fclose(
          &filep->access); /* ignore error on read only file */
      return;
    }
    conn->status_code = 206;
    cl = (n == 2) ? (((r2 > cl) ? cl : r2) - r1 + 1) : (cl - r1);
    mg_snprintf(conn,
                NULL, /* range buffer is big enough */
                range,
                sizeof(range),
                "bytes "
                "%" INT64_FMT "-%" INT64_FMT "/%" INT64_FMT,
                r1,
                r1 + cl - 1,
                filep->stat.size);

#if defined(USE_ZLIB)
    /* Do not compress ranges. */
    allow_on_the_fly_compression = 0;
#endif
  }

  /* Do not compress small files. Small files do not benefit from file
   * compression, but there is still some overhead. */
#if defined(USE_ZLIB)
  if (filep->stat.size < MG_FILE_COMPRESSION_SIZE_LIMIT) {
    /* File is below the size limit. */
    allow_on_the_fly_compression = 0;
  }
#endif

  /* Prepare Etag, and Last-Modified headers. */
  gmt_time_string(lm, sizeof(lm), &filep->stat.last_modified);
  construct_etag(etag, sizeof(etag), &filep->stat);

  /* Create 2xx (200, 206) response */
  mg_response_header_start(conn, conn->status_code);
  send_static_cache_header(conn);
  send_additional_header(conn);
  send_cors_header(conn);
  mg_response_header_add(conn,
                         "Content-Type",
                         mime_vec.ptr,
                         (int)mime_vec.len);
  mg_response_header_add(conn, "Last-Modified", lm, -1);
  mg_response_header_add(conn, "Etag", etag, -1);

#if defined(USE_ZLIB)
  /* On the fly compression allowed */
  if (allow_on_the_fly_compression) {
    /* For on the fly compression, we don't know the content size in
     * advance, so we have to use chunked encoding */
    encoding = "gzip";
    if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
      /* HTTP/2 is always using "chunks" (frames) */
      mg_response_header_add(conn, "Transfer-Encoding", "chunked", -1);
    }

  } else
#endif
  {
    /* Without on-the-fly compression, we know the content-length
     * and we can use ranges (with on-the-fly compression we cannot).
     * So we send these response headers only in this case. */
    char len[32];
    int trunc = 0;
    mg_snprintf(conn, &trunc, len, sizeof(len), "%" INT64_FMT, cl);

    if (!trunc) {
      mg_response_header_add(conn, "Content-Length", len, -1);
    }

    mg_response_header_add(conn, "Accept-Ranges", "bytes", -1);
  }

  if (encoding) {
    mg_response_header_add(conn, "Content-Encoding", encoding, -1);
  }
  if (range[0] != 0) {
    mg_response_header_add(conn, "Content-Range", range, -1);
  }

  /* The code above does not add any header starting with X- to make
   * sure no one of the additional_headers is included twice */
  if ((additional_headers != NULL) && (*additional_headers != 0)) {
    mg_response_header_add_lines(conn, additional_headers);
  }

  /* Send all headers */
  mg_response_header_send(conn);

  if (!is_head_request) {
#if defined(USE_ZLIB)
    if (allow_on_the_fly_compression) {
      /* Compress and send */
      send_compressed_data(conn, filep);
    } else
#endif
    {
      /* Send file directly */
      send_file_data(conn, filep, r1, cl, 0); /* send static file */
    }
  }
  (void)mg_fclose(&filep->access); /* ignore error on read only file */
}


CIVETWEB_API int
mg_send_file_body(struct mg_connection *conn, const char *path)
{
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, &file)) {
    return -1;
  }
  fclose_on_exec(&file.access, conn);
  send_file_data(conn, &file, 0, INT64_MAX, 0); /* send static file */
  (void)mg_fclose(&file.access); /* Ignore errors for readonly files */
  return 0;                      /* >= 0 for OK */
}
#endif /* NO_FILESYSTEMS */


#if !defined(NO_CACHING)
/* Return True if we should reply 304 Not Modified. */
static int
is_not_modified(const struct mg_connection *conn,
                const struct mg_file_stat *filestat)
{
  char etag[64];
  const char *ims = mg_get_header(conn, "If-Modified-Since");
  const char *inm = mg_get_header(conn, "If-None-Match");
  construct_etag(etag, sizeof(etag), filestat);

  return ((inm != NULL) && !mg_strcasecmp(etag, inm))
         || ((ims != NULL)
             && (filestat->last_modified <= parse_date_string(ims)));
}


static void
handle_not_modified_static_file_request(struct mg_connection *conn,
                                        struct mg_file *filep)
{
  char lm[64], etag[64];

  if ((conn == NULL) || (filep == NULL)) {
    return;
  }

  gmt_time_string(lm, sizeof(lm), &filep->stat.last_modified);
  construct_etag(etag, sizeof(etag), &filep->stat);

  /* Create 304 "not modified" response */
  mg_response_header_start(conn, 304);
  send_static_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn, "Last-Modified", lm, -1);
  mg_response_header_add(conn, "Etag", etag, -1);

  /* Send all headers */
  mg_response_header_send(conn);
}
#endif


#if !defined(NO_FILESYSTEMS)
CIVETWEB_API void
mg_send_file(struct mg_connection *conn, const char *path)
{
  mg_send_mime_file2(conn, path, NULL, NULL);
}


CIVETWEB_API void
mg_send_mime_file(struct mg_connection *conn,
                  const char *path,
                  const char *mime_type)
{
  mg_send_mime_file2(conn, path, mime_type, NULL);
}


CIVETWEB_API void
mg_send_mime_file2(struct mg_connection *conn,
                   const char *path,
                   const char *mime_type,
                   const char *additional_headers)
{
  struct mg_file file = STRUCT_FILE_INITIALIZER;

  if (!conn) {
    /* No conn */
    return;
  }

  if (mg_stat(conn, path, &file.stat)) {
#if !defined(NO_CACHING)
    if (is_not_modified(conn, &file.stat)) {
      /* Send 304 "Not Modified" - this must not send any body data */
      handle_not_modified_static_file_request(conn, &file);
    } else
#endif /* NO_CACHING */
        if (file.stat.is_directory) {
      if (!mg_strcasecmp(conn->dom_ctx->config[ENABLE_DIRECTORY_LISTING],
                         "yes")) {
        handle_directory_request(conn, path);
      } else {
        mg_send_http_error(conn,
                           403,
                           "%s",
                           "Error: Directory listing denied");
      }
    } else {
      handle_static_file_request(
          conn, path, &file, mime_type, additional_headers);
    }
  } else {
    mg_send_http_error(conn, 404, "%s", "Error: File not found");
  }
}


/* For a given PUT path, create all intermediate subdirectories.
 * Return  0  if the path itself is a directory.
 * Return  1  if the path leads to a file.
 * Return -1  for if the path is too long.
 * Return -2  if path can not be created.
 */
static int
put_dir(struct mg_connection *conn, const char *path)
{
  char buf[UTF8_PATH_MAX];
  const char *s, *p;
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  size_t len;
  int res = 1;

  for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p) {
    len = (size_t)(p - path);
    if (len >= sizeof(buf)) {
      /* path too long */
      res = -1;
      break;
    }
    memcpy(buf, path, len);
    buf[len] = '\0';

    /* Try to create intermediate directory */
    DEBUG_TRACE("mkdir(%s)", buf);
    if (!mg_stat(conn, buf, &file.stat) && mg_mkdir(conn, buf, 0755) != 0) {
      /* path does not exist and can not be created */
      res = -2;
      break;
    }

    /* Is path itself a directory? */
    if (p[1] == '\0') {
      res = 0;
    }
  }

  return res;
}


static void
remove_bad_file(const struct mg_connection *conn, const char *path)
{
  int r = mg_remove(conn, path);
  if (r != 0) {
    mg_cry_internal(conn,
                    "%s: Cannot remove invalid file %s",
                    __func__,
                    path);
  }
}


CIVETWEB_API long long
mg_store_body(struct mg_connection *conn, const char *path)
{
  char buf[MG_BUF_LEN];
  long long len = 0;
  int ret, n;
  struct mg_file fi;

  if (conn->consumed_content != 0) {
    mg_cry_internal(conn, "%s: Contents already consumed", __func__);
    return -11;
  }

  ret = put_dir(conn, path);
  if (ret < 0) {
    /* -1 for path too long,
     * -2 for path can not be created. */
    return ret;
  }
  if (ret != 1) {
    /* Return 0 means, path itself is a directory. */
    return 0;
  }

  if (mg_fopen(conn, path, MG_FOPEN_MODE_WRITE, &fi) == 0) {
    return -12;
  }

  ret = mg_read(conn, buf, sizeof(buf));
  while (ret > 0) {
    n = (int)fwrite(buf, 1, (size_t)ret, fi.access.fp);
    if (n != ret) {
      (void)mg_fclose(
          &fi.access); /* File is bad and will be removed anyway. */
      remove_bad_file(conn, path);
      return -13;
    }
    len += ret;
    ret = mg_read(conn, buf, sizeof(buf));
  }

  /* File is open for writing. If fclose fails, there was probably an
   * error flushing the buffer to disk, so the file on disk might be
   * broken. Delete it and return an error to the caller. */
  if (mg_fclose(&fi.access) != 0) {
    remove_bad_file(conn, path);
    return -14;
  }

  return len;
}
#endif /* NO_FILESYSTEMS */


/* Parse a buffer:
 * Forward the string pointer till the end of a word, then
 * terminate it and forward till the begin of the next word.
 */
static int
skip_to_end_of_word_and_terminate(char **ppw, int eol)
{
  /* Forward until a space is found - use isgraph here */
  /* See http://www.cplusplus.com/reference/cctype/ */
  while (isgraph((unsigned char)**ppw)) {
    (*ppw)++;
  }

  /* Check end of word */
  if (eol) {
    /* must be a end of line */
    if ((**ppw != '\r') && (**ppw != '\n')) {
      return -1;
    }
  } else {
    /* must be a end of a word, but not a line */
    if (**ppw != ' ') {
      return -1;
    }
  }

  /* Terminate and forward to the next word */
  do {
    **ppw = 0;
    (*ppw)++;
  } while (isspace((unsigned char)**ppw));

  /* Check after term */
  if (!eol) {
    /* if it's not the end of line, there must be a next word */
    if (!isgraph((unsigned char)**ppw)) {
      return -1;
    }
  }

  /* ok */
  return 1;
}


/* Parse HTTP headers from the given buffer, advance buf pointer
 * to the point where parsing stopped.
 * All parameters must be valid pointers (not NULL).
 * Return <0 on error. */
static int
parse_http_headers(char **buf, struct mg_header hdr[MG_MAX_HEADERS])
{
  int i;
  int num_headers = 0;

  for (i = 0; i < (int)MG_MAX_HEADERS; i++) {
    char *dp = *buf;

    /* Skip all ASCII characters (>SPACE, <127), to find a ':' */
    while ((*dp != ':') && (*dp >= 33) && (*dp <= 126)) {
      dp++;
    }
    if (dp == *buf) {
      /* End of headers reached. */
      break;
    }

    /* Drop all spaces after header name before : */
    while (*dp == ' ') {
      *dp = 0;
      dp++;
    }
    if (*dp != ':') {
      /* This is not a valid field. */
      return -1;
    }

    /* End of header key (*dp == ':') */
    /* Truncate here and set the key name */
    *dp = 0;
    hdr[i].name = *buf;

    /* Skip all spaces */
    do {
      dp++;
    } while ((*dp == ' ') || (*dp == '\t'));

    /* The rest of the line is the value */
    hdr[i].value = dp;

    /* Find end of line */
    while ((*dp != 0) && (*dp != '\r') && (*dp != '\n')) {
      dp++;
    };

    /* eliminate \r */
    if (*dp == '\r') {
      *dp = 0;
      dp++;
      if (*dp != '\n') {
        /* This is not a valid line. */
        return -1;
      }
    }

    /* here *dp is either 0 or '\n' */
    /* in any case, we have a new header */
    num_headers = i + 1;

    if (*dp) {
      *dp = 0;
      dp++;
      *buf = dp;

      if ((dp[0] == '\r') || (dp[0] == '\n')) {
        /* This is the end of the header */
        break;
      }
    } else {
      *buf = dp;
      break;
    }
  }
  return num_headers;
}


struct mg_http_method_info {
  const char *name;
  int request_has_body;
  int response_has_body;
  int is_safe;
  int is_idempotent;
  int is_cacheable;
};


/* https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods */
static const struct mg_http_method_info http_methods[] = {
    /* HTTP (RFC 2616) */
    {"GET", 0, 1, 1, 1, 1},
    {"POST", 1, 1, 0, 0, 0},
    {"PUT", 1, 0, 0, 1, 0},
    {"DELETE", 0, 0, 0, 1, 0},
    {"HEAD", 0, 0, 1, 1, 1},
    {"OPTIONS", 0, 0, 1, 1, 0},
    {"CONNECT", 1, 1, 0, 0, 0},
    /* TRACE method (RFC 2616) is not supported for security reasons */

    /* PATCH method (RFC 5789) */
    {"PATCH", 1, 0, 0, 0, 0},
    /* PATCH method only allowed for CGI/Lua/LSP and callbacks. */

    /* WEBDAV (RFC 2518) */
    {"PROPFIND", 0, 1, 1, 1, 0},
    /* http://www.webdav.org/specs/rfc4918.html, 9.1:
     * Some PROPFIND results MAY be cached, with care,
     * as there is no cache validation mechanism for
     * most properties. This method is both safe and
     * idempotent (see Section 9.1 of [RFC2616]). */
    {"MKCOL", 0, 0, 0, 1, 0},
    /* http://www.webdav.org/specs/rfc4918.html, 9.1:
     * When MKCOL is invoked without a request body,
     * the newly created collection SHOULD have no
     * members. A MKCOL request message may contain
     * a message body. The precise behavior of a MKCOL
     * request when the body is present is undefined,
     * ... ==> We do not support MKCOL with body data.
     * This method is idempotent, but not safe (see
     * Section 9.1 of [RFC2616]). Responses to this
     * method MUST NOT be cached. */

    /* Methods for write access to files on WEBDAV (RFC 2518) */
    {"LOCK", 1, 1, 0, 0, 0},
    {"UNLOCK", 1, 0, 0, 0, 0},
    {"PROPPATCH", 1, 1, 0, 0, 0},
    {"COPY", 1, 0, 0, 0, 0},
    {"MOVE", 1, 1, 0, 0, 0},

    /* Unsupported WEBDAV Methods: */
    /* + 11 methods from RFC 3253 */
    /* ORDERPATCH (RFC 3648) */
    /* ACL (RFC 3744) */
    /* SEARCH (RFC 5323) */
    /* + MicroSoft extensions
     * https://msdn.microsoft.com/en-us/library/aa142917.aspx */

    /* REPORT method (RFC 3253) */
    {"REPORT", 1, 1, 1, 1, 1},
    /* REPORT method only allowed for CGI/Lua/LSP and callbacks. */
    /* It was defined for WEBDAV in RFC 3253, Sec. 3.6
     * (https://tools.ietf.org/html/rfc3253#section-3.6), but seems
     * to be useful for REST in case a "GET request with body" is
     * required. */

    {NULL, 0, 0, 0, 0, 0}
    /* end of list */
};


/* All method names */
static char *all_methods = NULL; /* Built by mg_init_library */


static const struct mg_http_method_info *
get_http_method_info(const char *method)
{
  /* Check if the method is known to the server. The list of all known
   * HTTP methods can be found here at
   * http://www.iana.org/assignments/http-methods/http-methods.xhtml
   */
  const struct mg_http_method_info *m = http_methods;

  while (m->name) {
    if (!strcmp(m->name, method)) {
      return m;
    }
    m++;
  }
  return NULL;
}


static int
is_valid_http_method(const char *method)
{
  return (get_http_method_info(method) != NULL);
}


/* Parse HTTP request, fill in mg_request_info structure.
 * This function modifies the buffer by NUL-terminating
 * HTTP request components, header names and header values.
 * Parameters:
 *   buf (in/out): pointer to the HTTP header to parse and split
 *   len (in): length of HTTP header buffer
 *   re (out): parsed header as mg_request_info
 * buf and ri must be valid pointers (not NULL), len>0.
 * Returns <0 on error. */
static int
parse_http_request(char *buf, int len, struct mg_request_info *ri)
{
  int request_length;
  int init_skip = 0;

  /* Reset attributes. DO NOT TOUCH is_ssl, remote_addr,
   * remote_port */
  ri->remote_user = ri->request_method = ri->request_uri = ri->http_version =
      NULL;
  ri->num_headers = 0;

  /* RFC says that all initial whitespaces should be ignored */
  /* This included all leading \r and \n (isspace) */
  /* See table: http://www.cplusplus.com/reference/cctype/ */
  while ((len > 0) && isspace((unsigned char)*buf)) {
    buf++;
    len--;
    init_skip++;
  }

  if (len == 0) {
    /* Incomplete request */
    return 0;
  }

  /* Control characters are not allowed, including zero */
  if (iscntrl((unsigned char)*buf)) {
    return -1;
  }

  /* Find end of HTTP header */
  request_length = get_http_header_len(buf, len);
  if (request_length <= 0) {
    return request_length;
  }
  buf[request_length - 1] = '\0';

  if ((*buf == 0) || (*buf == '\r') || (*buf == '\n')) {
    return -1;
  }

  /* The first word has to be the HTTP method */
  ri->request_method = buf;

  if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
    return -1;
  }

  /* The second word is the URI */
  ri->request_uri = buf;

  if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
    return -1;
  }

  /* Next would be the HTTP version */
  ri->http_version = buf;

  if (skip_to_end_of_word_and_terminate(&buf, 1) <= 0) {
    return -1;
  }

  /* Check for a valid HTTP version key */
  if (strncmp(ri->http_version, "HTTP/", 5) != 0) {
    /* Invalid request */
    return -1;
  }
  ri->http_version += 5;

  /* Check for a valid http method */
  if (!is_valid_http_method(ri->request_method)) {
    return -1;
  }

  /* Parse all HTTP headers */
  ri->num_headers = parse_http_headers(&buf, ri->http_headers);
  if (ri->num_headers < 0) {
    /* Error while parsing headers */
    return -1;
  }

  return request_length + init_skip;
}


static int
parse_http_response(char *buf, int len, struct mg_response_info *ri)
{
  int response_length;
  int init_skip = 0;
  char *tmp, *tmp2;
  long l;

  /* Initialize elements. */
  ri->http_version = ri->status_text = NULL;
  ri->num_headers = ri->status_code = 0;

  /* RFC says that all initial whitespaces should be ignored */
  /* This included all leading \r and \n (isspace) */
  /* See table: http://www.cplusplus.com/reference/cctype/ */
  while ((len > 0) && isspace((unsigned char)*buf)) {
    buf++;
    len--;
    init_skip++;
  }

  if (len == 0) {
    /* Incomplete request */
    return 0;
  }

  /* Control characters are not allowed, including zero */
  if (iscntrl((unsigned char)*buf)) {
    return -1;
  }

  /* Find end of HTTP header */
  response_length = get_http_header_len(buf, len);
  if (response_length <= 0) {
    return response_length;
  }
  buf[response_length - 1] = '\0';

  if ((*buf == 0) || (*buf == '\r') || (*buf == '\n')) {
    return -1;
  }

  /* The first word is the HTTP version */
  /* Check for a valid HTTP version key */
  if (strncmp(buf, "HTTP/", 5) != 0) {
    /* Invalid request */
    return -1;
  }
  buf += 5;
  if (!isgraph((unsigned char)buf[0])) {
    /* Invalid request */
    return -1;
  }
  ri->http_version = buf;

  if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
    return -1;
  }

  /* The second word is the status as a number */
  tmp = buf;

  if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
    return -1;
  }

  l = strtol(tmp, &tmp2, 10);
  if ((l < 100) || (l >= 1000) || ((tmp2 - tmp) != 3) || (*tmp2 != 0)) {
    /* Everything else but a 3 digit code is invalid */
    return -1;
  }
  ri->status_code = (int)l;

  /* The rest of the line is the status text */
  ri->status_text = buf;

  /* Find end of status text */
  /* isgraph or isspace = isprint */
  while (isprint((unsigned char)*buf)) {
    buf++;
  }
  if ((*buf != '\r') && (*buf != '\n')) {
    return -1;
  }
  /* Terminate string and forward buf to next line */
  do {
    *buf = 0;
    buf++;
  } while (isspace((unsigned char)*buf));

  /* Parse all HTTP headers */
  ri->num_headers = parse_http_headers(&buf, ri->http_headers);
  if (ri->num_headers < 0) {
    /* Error while parsing headers */
    return -1;
  }

  return response_length + init_skip;
}


/* Keep reading the input (either opened file descriptor fd, or socket sock,
 * or SSL descriptor ssl) into buffer buf, until \r\n\r\n appears in the
 * buffer (which marks the end of HTTP request). Buffer buf may already
 * have some data. The length of the data is stored in nread.
 * Upon every read operation, increase nread by the number of bytes read. */
static int
read_message(FILE *fp,
             struct mg_connection *conn,
             char *buf,
             int bufsiz,
             int *nread)
{
  int request_len, n = 0;
  struct timespec last_action_time;
  double request_timeout;

  if (!conn) {
    return 0;
  }

  memset(&last_action_time, 0, sizeof(last_action_time));

  if (conn->dom_ctx->config[REQUEST_TIMEOUT]) {
    /* value of request_timeout is in seconds, config in milliseconds */
    request_timeout =
        strtod(conn->dom_ctx->config[REQUEST_TIMEOUT], NULL) / 1000.0;
  } else {
    request_timeout =
        strtod(config_options[REQUEST_TIMEOUT].default_value, NULL)
        / 1000.0;
  }
  if (conn->handled_requests > 0) {
    if (conn->dom_ctx->config[KEEP_ALIVE_TIMEOUT]) {
      request_timeout =
          strtod(conn->dom_ctx->config[KEEP_ALIVE_TIMEOUT], NULL)
          / 1000.0;
    }
  }

  request_len = get_http_header_len(buf, *nread);

  while (request_len == 0) {
    /* Full request not yet received */
    if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
      /* Server is to be stopped. */
      return -1;
    }

    if (*nread >= bufsiz) {
      /* Request too long */
      return -2;
    }

    n = pull_inner(
        fp, conn, buf + *nread, bufsiz - *nread, request_timeout);
    if (n == -2) {
      /* Receive error */
      return -1;
    }

    /* update clock after every read request */
    clock_gettime(CLOCK_MONOTONIC, &last_action_time);

    if (n > 0) {
      *nread += n;
      request_len = get_http_header_len(buf, *nread);
    }

    if ((request_len == 0) && (request_timeout >= 0)) {
      if (mg_difftimespec(&last_action_time, &(conn->req_time))
          > request_timeout) {
        /* Timeout */
        return -1;
      }
    }
  }

  return request_len;
}


#if !defined(NO_CGI) || !defined(NO_FILES)
static int
forward_body_data(struct mg_connection *conn, FILE *fp, SOCKET sock, SSL *ssl)
{
  const char *expect;
  char buf[MG_BUF_LEN];
  int success = 0;

  if (!conn) {
    return 0;
  }

  expect = mg_get_header(conn, "Expect");
  DEBUG_ASSERT(fp != NULL);
  if (!fp) {
    mg_send_http_error(conn, 500, "%s", "Error: NULL File");
    return 0;
  }

  if ((expect != NULL) && (mg_strcasecmp(expect, "100-continue") != 0)) {
    /* Client sent an "Expect: xyz" header and xyz is not 100-continue.
     */
    mg_send_http_error(conn, 417, "Error: Can not fulfill expectation");
  } else {
    if (expect != NULL) {
      (void)mg_printf(conn, "%s", "HTTP/1.1 100 Continue\r\n\r\n");
      conn->status_code = 100;
    } else {
      conn->status_code = 200;
    }

    DEBUG_ASSERT(conn->consumed_content == 0);

    if (conn->consumed_content != 0) {
      mg_send_http_error(conn, 500, "%s", "Error: Size mismatch");
      return 0;
    }

    for (;;) {
      int nread = mg_read(conn, buf, sizeof(buf));
      if (nread <= 0) {
        success = (nread == 0);
        break;
      }
      if (push_all(conn->phys_ctx, fp, sock, ssl, buf, nread) != nread) {
        break;
      }
    }

    /* Each error code path in this function must send an error */
    if (!success) {
      /* NOTE: Maybe some data has already been sent. */
      /* TODO (low): If some data has been sent, a correct error
       * reply can no longer be sent, so just close the connection */
      mg_send_http_error(conn, 500, "%s", "");
    }
  }

  return success;
}
#endif


#if defined(USE_TIMERS)

#define TIMER_API static
#include "timer.inl"

#endif /* USE_TIMERS */


#if !defined(NO_CGI)
/* This structure helps to create an environment for the spawned CGI
 * program.
 * Environment is an array of "VARIABLE=VALUE\0" ASCII strings,
 * last element must be NULL.
 * However, on Windows there is a requirement that all these
 * VARIABLE=VALUE\0
 * strings must reside in a contiguous buffer. The end of the buffer is
 * marked by two '\0' characters.
 * We satisfy both worlds: we create an envp array (which is vars), all
 * entries are actually pointers inside buf. */
struct cgi_environment {
  struct mg_connection *conn;
  /* Data block */
  char *buf;      /* Environment buffer */
  size_t buflen;  /* Space available in buf */
  size_t bufused; /* Space taken in buf */
  /* Index block */
  char **var;     /* char **envp */
  size_t varlen;  /* Number of variables available in var */
  size_t varused; /* Number of variables stored in var */
};


static void addenv(struct cgi_environment *env,
                   PRINTF_FORMAT_STRING(const char *fmt),
                   ...) PRINTF_ARGS(2, 3);

/* Append VARIABLE=VALUE\0 string to the buffer, and add a respective
 * pointer into the vars array. Assumes env != NULL and fmt != NULL. */
static void
addenv(struct cgi_environment *env, const char *fmt, ...)
{
  size_t i, n, space;
  int truncated = 0;
  char *added;
  va_list ap;

  if ((env->varlen - env->varused) < 2) {
    mg_cry_internal(env->conn,
                    "%s: Cannot register CGI variable [%s]",
                    __func__,
                    fmt);
    return;
  }

  /* Calculate how much space is left in the buffer */
  space = (env->buflen - env->bufused);

  do {
    /* Space for "\0\0" is always needed. */
    if (space <= 2) {
      /* Allocate new buffer */
      n = env->buflen + CGI_ENVIRONMENT_SIZE;
      added = (char *)mg_realloc_ctx(env->buf, n, env->conn->phys_ctx);
      if (!added) {
        /* Out of memory */
        mg_cry_internal(
            env->conn,
            "%s: Cannot allocate memory for CGI variable [%s]",
            __func__,
            fmt);
        return;
      }
      /* Retarget pointers */
      env->buf = added;
      env->buflen = n;
      for (i = 0, n = 0; i < env->varused; i++) {
        env->var[i] = added + n;
        n += strlen(added + n) + 1;
      }
      space = (env->buflen - env->bufused);
    }

    /* Make a pointer to the free space int the buffer */
    added = env->buf + env->bufused;

    /* Copy VARIABLE=VALUE\0 string into the free space */
    va_start(ap, fmt);
    mg_vsnprintf(env->conn, &truncated, added, space - 1, fmt, ap);
    va_end(ap);

    /* Do not add truncated strings to the environment */
    if (truncated) {
      /* Reallocate the buffer */
      space = 0;
    }
  } while (truncated);

  /* Calculate number of bytes added to the environment */
  n = strlen(added) + 1;
  env->bufused += n;

  /* Append a pointer to the added string into the envp array */
  env->var[env->varused] = added;
  env->varused++;
}

/* Return 0 on success, non-zero if an error occurs. */

static int
prepare_cgi_environment(struct mg_connection *conn,
                        const char *prog,
                        struct cgi_environment *env,
                        unsigned char cgi_config_idx)
{
  const char *s;
  struct vec var_vec;
  char *p, src_addr[IP_ADDR_STR_LEN], http_var_name[128];
  int i, truncated, uri_len;

  if ((conn == NULL) || (prog == NULL) || (env == NULL)) {
    return -1;
  }

  env->conn = conn;
  env->buflen = CGI_ENVIRONMENT_SIZE;
  env->bufused = 0;
  env->buf = (char *)mg_malloc_ctx(env->buflen, conn->phys_ctx);
  if (env->buf == NULL) {
    mg_cry_internal(conn,
                    "%s: Not enough memory for environmental buffer",
                    __func__);
    return -1;
  }
  env->varlen = MAX_CGI_ENVIR_VARS;
  env->varused = 0;
  env->var =
      (char **)mg_malloc_ctx(env->varlen * sizeof(char *), conn->phys_ctx);
  if (env->var == NULL) {
    mg_cry_internal(conn,
                    "%s: Not enough memory for environmental variables",
                    __func__);
    mg_free(env->buf);
    return -1;
  }

  addenv(env, "SERVER_NAME=%s", conn->dom_ctx->config[AUTHENTICATION_DOMAIN]);
  addenv(env, "SERVER_ROOT=%s", conn->dom_ctx->config[DOCUMENT_ROOT]);
  addenv(env, "DOCUMENT_ROOT=%s", conn->dom_ctx->config[DOCUMENT_ROOT]);
  addenv(env, "SERVER_SOFTWARE=CivetWeb/%s", mg_version());

  /* Prepare the environment block */
  addenv(env, "%s", "GATEWAY_INTERFACE=CGI/1.1");
  addenv(env, "%s", "SERVER_PROTOCOL=HTTP/1.1");
  addenv(env, "%s", "REDIRECT_STATUS=200"); /* For PHP */

  addenv(env, "SERVER_PORT=%d", conn->request_info.server_port);

  sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
  addenv(env, "REMOTE_ADDR=%s", src_addr);

  addenv(env, "REQUEST_METHOD=%s", conn->request_info.request_method);
  addenv(env, "REMOTE_PORT=%d", conn->request_info.remote_port);

  addenv(env, "REQUEST_URI=%s", conn->request_info.request_uri);
  addenv(env, "LOCAL_URI=%s", conn->request_info.local_uri);
  addenv(env, "LOCAL_URI_RAW=%s", conn->request_info.local_uri_raw);

  /* SCRIPT_NAME */
  uri_len = (int)strlen(conn->request_info.local_uri);
  if (conn->path_info == NULL) {
    if (conn->request_info.local_uri[uri_len - 1] != '/') {
      /* URI: /path_to_script/script.cgi */
      addenv(env, "SCRIPT_NAME=%s", conn->request_info.local_uri);
    } else {
      /* URI: /path_to_script/ ... using index.cgi */
      const char *index_file = strrchr(prog, '/');
      if (index_file) {
        addenv(env,
               "SCRIPT_NAME=%s%s",
               conn->request_info.local_uri,
               index_file + 1);
      }
    }
  } else {
    /* URI: /path_to_script/script.cgi/path_info */
    addenv(env,
           "SCRIPT_NAME=%.*s",
           uri_len - (int)strlen(conn->path_info),
           conn->request_info.local_uri);
  }

  addenv(env, "SCRIPT_FILENAME=%s", prog);
  if (conn->path_info == NULL) {
    addenv(env, "PATH_TRANSLATED=%s", conn->dom_ctx->config[DOCUMENT_ROOT]);
  } else {
    addenv(env,
           "PATH_TRANSLATED=%s%s",
           conn->dom_ctx->config[DOCUMENT_ROOT],
           conn->path_info);
  }

  addenv(env, "HTTPS=%s", (conn->ssl == NULL) ? "off" : "on");

  if ((s = mg_get_header(conn, "Content-Type")) != NULL) {
    addenv(env, "CONTENT_TYPE=%s", s);
  }
  if (conn->request_info.query_string != NULL) {
    addenv(env, "QUERY_STRING=%s", conn->request_info.query_string);
  }
  if ((s = mg_get_header(conn, "Content-Length")) != NULL) {
    addenv(env, "CONTENT_LENGTH=%s", s);
  }
  if ((s = getenv("PATH")) != NULL) {
    addenv(env, "PATH=%s", s);
  }
  if (conn->path_info != NULL) {
    addenv(env, "PATH_INFO=%s", conn->path_info);
  }

  if (conn->status_code > 0) {
    /* CGI error handler should show the status code */
    addenv(env, "STATUS=%d", conn->status_code);
  }

#if defined(_WIN32)
  if ((s = getenv("COMSPEC")) != NULL) {
    addenv(env, "COMSPEC=%s", s);
  }
  if ((s = getenv("SYSTEMROOT")) != NULL) {
    addenv(env, "SYSTEMROOT=%s", s);
  }
  if ((s = getenv("SystemDrive")) != NULL) {
    addenv(env, "SystemDrive=%s", s);
  }
  if ((s = getenv("ProgramFiles")) != NULL) {
    addenv(env, "ProgramFiles=%s", s);
  }
  if ((s = getenv("ProgramFiles(x86)")) != NULL) {
    addenv(env, "ProgramFiles(x86)=%s", s);
  }
#else
  if ((s = getenv("LD_LIBRARY_PATH")) != NULL) {
    addenv(env, "LD_LIBRARY_PATH=%s", s);
  }
#endif /* _WIN32 */

  if ((s = getenv("PERLLIB")) != NULL) {
    addenv(env, "PERLLIB=%s", s);
  }

  if (conn->request_info.remote_user != NULL) {
    addenv(env, "REMOTE_USER=%s", conn->request_info.remote_user);
    addenv(env, "%s", "AUTH_TYPE=Digest");
  }

  /* Add all headers as HTTP_* variables */
  for (i = 0; i < conn->request_info.num_headers; i++) {

    (void)mg_snprintf(conn,
                      &truncated,
                      http_var_name,
                      sizeof(http_var_name),
                      "HTTP_%s",
                      conn->request_info.http_headers[i].name);

    if (truncated) {
      mg_cry_internal(conn,
                      "%s: HTTP header variable too long [%s]",
                      __func__,
                      conn->request_info.http_headers[i].name);
      continue;
    }

    /* Convert variable name into uppercase, and change - to _ */
    for (p = http_var_name; *p != '\0'; p++) {
      if (*p == '-') {
        *p = '_';
      }
      *p = (char)toupper((unsigned char)*p);
    }

    addenv(env,
           "%s=%s",
           http_var_name,
           conn->request_info.http_headers[i].value);
  }

  /* Add user-specified variables */
  s = conn->dom_ctx->config[CGI_ENVIRONMENT + cgi_config_idx];
  while ((s = next_option(s, &var_vec, NULL)) != NULL) {
    addenv(env, "%.*s", (int)var_vec.len, var_vec.ptr);
  }

  env->var[env->varused] = NULL;
  env->buf[env->bufused] = '\0';

  return 0;
}


/* Data for CGI process control: PID and number of references */
struct process_control_data {
  pid_t pid;
  ptrdiff_t references;
};

static int
abort_cgi_process(void *data)
{
  /* Waitpid checks for child status and won't work for a pid that does
   * not identify a child of the current process. Thus, if the pid is
   * reused, we will not affect a different process. */
  struct process_control_data *proc = (struct process_control_data *)data;
  int status = 0;
  ptrdiff_t refs;
  pid_t ret_pid;

  ret_pid = waitpid(proc->pid, &status, WNOHANG);
  if ((ret_pid != (pid_t)-1) && (status == 0)) {
    /* Stop child process */
    DEBUG_TRACE("CGI timer: Stop child process %d\n", proc->pid);
    kill(proc->pid, SIGABRT);

    /* Wait until process is terminated (don't leave zombies) */
    while (waitpid(proc->pid, &status, 0) != (pid_t)-1) /* nop */
      ;
  } else {
    DEBUG_TRACE("CGI timer: Child process %d already stopped\n", proc->pid);
  }
  /* Dec reference counter */
  refs = mg_atomic_dec(&proc->references);
  if (refs == 0) {
    /* no more references - free data */
    mg_free(data);
  }

  return 0;
}


/* Local (static) function assumes all arguments are valid. */
static void
handle_cgi_request(struct mg_connection *conn,
                   const char *prog,
                   unsigned char cgi_config_idx)
{
  char *buf;
  size_t buflen;
  int headers_len, data_len, i, truncated;
  int fdin[2] = {-1, -1}, fdout[2] = {-1, -1}, fderr[2] = {-1, -1};
  const char *status, *status_text;
  char *pbuf, dir[UTF8_PATH_MAX], *p;
  struct mg_request_info ri;
  struct cgi_environment blk;
  FILE *in = NULL, *out = NULL, *err = NULL;
  struct mg_file fout = STRUCT_FILE_INITIALIZER;
  pid_t pid = (pid_t)-1;
  struct process_control_data *proc = NULL;
  char *cfg_buffering = conn->dom_ctx->config[CGI_BUFFERING + cgi_config_idx];
  int no_buffering = 0;

#if defined(USE_TIMERS)
  double cgi_timeout;
  if (conn->dom_ctx->config[CGI_TIMEOUT + cgi_config_idx]) {
    /* Get timeout in seconds */
    cgi_timeout =
        atof(conn->dom_ctx->config[CGI_TIMEOUT + cgi_config_idx]) * 0.001;
  } else {
    cgi_timeout =
        atof(config_options[REQUEST_TIMEOUT].default_value) * 0.001;
  }
#endif
  if (cfg_buffering != NULL) {
    if (!mg_strcasecmp(cfg_buffering, "no")) {
      no_buffering = 1;
    }
  }

  buf = NULL;
  buflen = conn->phys_ctx->max_request_size;
  i = prepare_cgi_environment(conn, prog, &blk, cgi_config_idx);
  if (i != 0) {
    blk.buf = NULL;
    blk.var = NULL;
    goto done;
  }

  /* CGI must be executed in its own directory. 'dir' must point to the
   * directory containing executable program, 'p' must point to the
   * executable program name relative to 'dir'. */
  (void)mg_snprintf(conn, &truncated, dir, sizeof(dir), "%s", prog);

  if (truncated) {
    mg_cry_internal(conn, "Error: CGI program \"%s\": Path too long", prog);
    mg_send_http_error(conn, 500, "Error: %s", "CGI path too long");
    goto done;
  }

  if ((p = strrchr(dir, '/')) != NULL) {
    *p++ = '\0';
  } else {
    dir[0] = '.';
    dir[1] = '\0';
    p = (char *)prog;
  }

  if ((pipe(fdin) != 0) || (pipe(fdout) != 0) || (pipe(fderr) != 0)) {
    status = strerror(ERRNO);
    mg_cry_internal(
        conn,
        "Error: CGI program \"%s\": Can not create CGI pipes: %s",
        prog,
        status);
    mg_send_http_error(conn,
                       500,
                       "Error: Cannot create CGI pipe: %s",
                       status);
    goto done;
  }

  proc = (struct process_control_data *)
      mg_malloc_ctx(sizeof(struct process_control_data), conn->phys_ctx);
  if (proc == NULL) {
    mg_cry_internal(conn, "Error: CGI program \"%s\": Out or memory", prog);
    mg_send_http_error(conn, 500, "Error: Out of memory [%s]", prog);
    goto done;
  }

  DEBUG_TRACE("CGI: spawn %s %s\n", dir, p);
  pid = spawn_process(
      conn, p, blk.buf, blk.var, fdin, fdout, fderr, dir, cgi_config_idx);

  if (pid == (pid_t)-1) {
    status = strerror(ERRNO);
    mg_cry_internal(
        conn,
        "Error: CGI program \"%s\": Can not spawn CGI process: %s",
        prog,
        status);
    mg_send_http_error(conn, 500, "Error: Cannot spawn CGI process");
    mg_free(proc);
    proc = NULL;
    goto done;
  }

  /* Store data in shared process_control_data */
  proc->pid = pid;
  proc->references = 1;

#if defined(USE_TIMERS)
  if (cgi_timeout > 0.0) {
    proc->references = 2;

    // Start a timer for CGI
    timer_add(conn->phys_ctx,
              cgi_timeout /* in seconds */,
              0.0,
              1,
              abort_cgi_process,
              (void *)proc,
              NULL);
  }
#endif

  /* Parent closes only one side of the pipes.
   * If we don't mark them as closed, close() attempt before
   * return from this function throws an exception on Windows.
   * Windows does not like when closed descriptor is closed again. */
  (void)close(fdin[0]);
  (void)close(fdout[1]);
  (void)close(fderr[1]);
  fdin[0] = fdout[1] = fderr[1] = -1;

  if (((in = fdopen(fdin[1], "wb")) == NULL)
      || ((out = fdopen(fdout[0], "rb")) == NULL)
      || ((err = fdopen(fderr[0], "rb")) == NULL)) {
    status = strerror(ERRNO);
    mg_cry_internal(conn,
                    "Error: CGI program \"%s\": Can not open fd: %s",
                    prog,
                    status);
    mg_send_http_error(conn,
                       500,
                       "Error: CGI can not open fd\nfdopen: %s",
                       status);
    goto done;
  }

  setbuf(in, NULL);
  setbuf(out, NULL);
  setbuf(err, NULL);
  fout.access.fp = out;

  if ((conn->content_len != 0) || (conn->is_chunked)) {
    DEBUG_TRACE("CGI: send body data (%" INT64_FMT ")\n",
                conn->content_len);

    /* This is a POST/PUT request, or another request with body data. */
    if (!forward_body_data(conn, in, INVALID_SOCKET, NULL)) {
      /* Error sending the body data */
      mg_cry_internal(
          conn,
          "Error: CGI program \"%s\": Forward body data failed",
          prog);
      goto done;
    }
  }

  /* Close so child gets an EOF. */
  fclose(in);
  in = NULL;
  fdin[1] = -1;

  /* Now read CGI reply into a buffer. We need to set correct
   * status code, thus we need to see all HTTP headers first.
   * Do not send anything back to client, until we buffer in all
   * HTTP headers. */
  data_len = 0;
  buf = (char *)mg_malloc_ctx(buflen, conn->phys_ctx);
  if (buf == NULL) {
    mg_send_http_error(conn,
                       500,
                       "Error: Not enough memory for CGI buffer (%u bytes)",
                       (unsigned int)buflen);
    mg_cry_internal(
        conn,
        "Error: CGI program \"%s\": Not enough memory for buffer (%u "
        "bytes)",
        prog,
        (unsigned int)buflen);
    goto done;
  }

  DEBUG_TRACE("CGI: %s", "wait for response");
  headers_len = read_message(out, conn, buf, (int)buflen, &data_len);
  DEBUG_TRACE("CGI: response: %li", (signed long)headers_len);

  if (headers_len <= 0) {

    /* Could not parse the CGI response. Check if some error message on
     * stderr. */
    i = pull_all(err, conn, buf, (int)buflen);
    if (i > 0) {
      /* CGI program explicitly sent an error */
      /* Write the error message to the internal log */
      mg_cry_internal(conn,
                      "Error: CGI program \"%s\" sent error "
                      "message: [%.*s]",
                      prog,
                      i,
                      buf);
      /* Don't send the error message back to the client */
      mg_send_http_error(conn,
                         500,
                         "Error: CGI program \"%s\" failed.",
                         prog);
    } else {
      /* CGI program did not explicitly send an error, but a broken
       * respon header */
      mg_cry_internal(conn,
                      "Error: CGI program sent malformed or too big "
                      "(>%u bytes) HTTP headers: [%.*s]",
                      (unsigned)buflen,
                      data_len,
                      buf);

      mg_send_http_error(conn,
                         500,
                         "Error: CGI program sent malformed or too big "
                         "(>%u bytes) HTTP headers: [%.*s]",
                         (unsigned)buflen,
                         data_len,
                         buf);
    }

    /* in both cases, abort processing CGI */
    goto done;
  }

  pbuf = buf;
  buf[headers_len - 1] = '\0';
  ri.num_headers = parse_http_headers(&pbuf, ri.http_headers);

  /* Make up and send the status line */
  status_text = "OK";
  if ((status = get_header(ri.http_headers, ri.num_headers, "Status"))
      != NULL) {
    conn->status_code = atoi(status);
    status_text = status;
    while (isdigit((unsigned char)*status_text) || *status_text == ' ') {
      status_text++;
    }
  } else if (get_header(ri.http_headers, ri.num_headers, "Location")
             != NULL) {
    conn->status_code = 307;
  } else {
    conn->status_code = 200;
  }

  if (!should_keep_alive(conn)) {
    conn->must_close = 1;
  }

  DEBUG_TRACE("CGI: response %u %s", conn->status_code, status_text);

  (void)mg_printf(conn, "HTTP/1.1 %d %s\r\n", conn->status_code, status_text);

  /* Send headers */
  for (i = 0; i < ri.num_headers; i++) {
    DEBUG_TRACE("CGI header: %s: %s",
                ri.http_headers[i].name,
                ri.http_headers[i].value);
    mg_printf(conn,
              "%s: %s\r\n",
              ri.http_headers[i].name,
              ri.http_headers[i].value);
  }
  mg_write(conn, "\r\n", 2);

  /* Send chunk of data that may have been read after the headers */
  mg_write(conn, buf + headers_len, (size_t)(data_len - headers_len));

  /* Read the rest of CGI output and send to the client */
  DEBUG_TRACE("CGI: %s", "forward all data");
  send_file_data(conn, &fout, 0, INT64_MAX, no_buffering); /* send CGI data */
  DEBUG_TRACE("CGI: %s", "all data sent");

done:
  mg_free(blk.var);
  mg_free(blk.buf);

  if (pid != (pid_t)-1) {
    abort_cgi_process((void *)proc);
  }

  if (fdin[0] != -1) {
    close(fdin[0]);
  }
  if (fdout[1] != -1) {
    close(fdout[1]);
  }
  if (fderr[1] != -1) {
    close(fderr[1]);
  }

  if (in != NULL) {
    fclose(in);
  } else if (fdin[1] != -1) {
    close(fdin[1]);
  }

  if (out != NULL) {
    fclose(out);
  } else if (fdout[0] != -1) {
    close(fdout[0]);
  }

  if (err != NULL) {
    fclose(err);
  } else if (fderr[0] != -1) {
    close(fderr[0]);
  }

  mg_free(buf);
}
#endif /* !NO_CGI */


#if !defined(NO_FILES)
static void
dav_mkcol(struct mg_connection *conn, const char *path)
{
  int rc, body_len;
  struct de de;

  if (conn == NULL) {
    return;
  }

  /* TODO (mid): Check the mg_send_http_error situations in this function
   */

  memset(&de.file, 0, sizeof(de.file));
  if (!mg_stat(conn, path, &de.file)) {
    mg_cry_internal(conn,
                    "%s: mg_stat(%s) failed: %s",
                    __func__,
                    path,
                    strerror(ERRNO));
  }

  if (de.file.last_modified) {
    /* TODO (mid): This check does not seem to make any sense ! */
    /* TODO (mid): Add a webdav unit test first, before changing
     * anything here. */
    mg_send_http_error(
        conn, 405, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    return;
  }

  body_len = conn->data_len - conn->request_len;
  if (body_len > 0) {
    mg_send_http_error(
        conn, 415, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    return;
  }

  rc = mg_mkdir(conn, path, 0755);
  DEBUG_TRACE("mkdir %s: %i", path, rc);
  if (rc == 0) {
    /* Create 201 "Created" response */
    mg_response_header_start(conn, 201);
    send_static_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn, "Content-Length", "0", -1);

    /* Send all headers - there is no body */
    mg_response_header_send(conn);
  } else {
    int http_status = 500;
    switch (errno) {
    case EEXIST:
      http_status = 405;
      break;
    case EACCES:
      http_status = 403;
      break;
    case ENOENT:
      http_status = 409;
      break;
    }

    mg_send_http_error(conn,
                       http_status,
                       "Error processing %s: %s",
                       path,
                       strerror(ERRNO));
  }
}


/* Forward decrlaration */
static int get_uri_type(const char *uri);
static const char *
get_rel_url_at_current_server(const char *uri,
                              const struct mg_connection *conn);


static void
dav_move_file(struct mg_connection *conn, const char *path, int do_copy)
{
  const char *overwrite_hdr;
  const char *destination_hdr;
  const char *root;
  int rc, dest_uri_type;
  int http_status = 400;
  int do_overwrite = 0;
  int destination_ok = 0;
  char dest_path[UTF8_PATH_MAX];
  struct mg_file_stat ignored;

  if (conn == NULL) {
    return;
  }

  root = conn->dom_ctx->config[DOCUMENT_ROOT];
  overwrite_hdr = mg_get_header(conn, "Overwrite");
  destination_hdr = mg_get_header(conn, "Destination");
  if ((overwrite_hdr != NULL) && (toupper(overwrite_hdr[0]) == 'T')) {
    do_overwrite = 1;
  }

  if ((destination_hdr == NULL) || (destination_hdr[0] == 0)) {
    mg_send_http_error(conn, 400, "%s", "Missing destination");
    return;
  }

  if (root != NULL) {
    char *local_dest = NULL;
    dest_uri_type = get_uri_type(destination_hdr);
    if (dest_uri_type == 2) {
      local_dest = mg_strdup_ctx(destination_hdr, conn->phys_ctx);
    } else if ((dest_uri_type == 3) || (dest_uri_type == 4)) {
      const char *h =
          get_rel_url_at_current_server(destination_hdr, conn);
      if (h) {
        int len = (int)strlen(h);
        local_dest = mg_malloc_ctx(len + 1, conn->phys_ctx);
        mg_url_decode(h, len, local_dest, len + 1, 0);
      }
    }
    if (local_dest != NULL) {
      remove_dot_segments(local_dest);
      if (local_dest[0] == '/') {
        int trunc_check = 0;
        mg_snprintf(conn,
                    &trunc_check,
                    dest_path,
                    sizeof(dest_path),
                    "%s/%s",
                    root,
                    local_dest);
        if (trunc_check == 0) {
          destination_ok = 1;
        }
      }
      mg_free(local_dest);
    }
  }

  if (!destination_ok) {
    mg_send_http_error(conn, 502, "%s", "Illegal destination");
    return;
  }

  /* Check now if this file exists */
  if (mg_stat(conn, dest_path, &ignored)) {
    /* File exists */
    if (do_overwrite) {
      /* Overwrite allowed: delete the file first */
      if (0 != remove(dest_path)) {
        /* No overwrite: return error */
        mg_send_http_error(conn,
                           403,
                           "Cannot overwrite file: %s",
                           dest_path);
        return;
      }
    } else {
      /* No overwrite: return error */
      mg_send_http_error(conn,
                         412,
                         "Destination already exists: %s",
                         dest_path);
      return;
    }
  }

  /* Copy / Move / Rename operation. */
  DEBUG_TRACE("%s %s to %s", (do_copy ? "copy" : "move"), path, dest_path);
#if defined(_WIN32)
  {
    /* For Windows, we need to convert from UTF-8 to UTF-16 first. */
    wchar_t wSource[UTF16_PATH_MAX];
    wchar_t wDest[UTF16_PATH_MAX];
    BOOL ok;

    path_to_unicode(conn, path, wSource, ARRAY_SIZE(wSource));
    path_to_unicode(conn, dest_path, wDest, ARRAY_SIZE(wDest));
    if (do_copy) {
      ok = CopyFileW(wSource, wDest, do_overwrite ? FALSE : TRUE);
    } else {
      ok = MoveFileExW(wSource,
                       wDest,
                       do_overwrite ? MOVEFILE_REPLACE_EXISTING : 0);
    }
    if (ok) {
      rc = 0;
    } else {
      DWORD lastErr = GetLastError();
      if (lastErr == ERROR_ALREADY_EXISTS) {
        mg_send_http_error(conn,
                           412,
                           "Destination already exists: %s",
                           dest_path);
        return;
      }
      rc = -1;
      http_status = 400;
    }
  }

#else
  {
    /* Linux uses already UTF-8, we don't need to convert file names. */

    if (do_copy) {
      /* TODO: COPY for Linux. */
      mg_send_http_error(conn, 403, "%s", "COPY forbidden");
      return;
    }

    rc = rename(path, dest_path);
    if (rc) {
      switch (errno) {
      case EEXIST:
        http_status = 412;
        break;
      case EACCES:
        http_status = 403;
        break;
      case ENOENT:
        http_status = 409;
        break;
      }
    }
  }
#endif

  if (rc == 0) {
    /* Create 204 "No Content" response */
    mg_response_header_start(conn, 204);
    mg_response_header_add(conn, "Content-Length", "0", -1);

    /* Send all headers - there is no body */
    mg_response_header_send(conn);
  } else {
    mg_send_http_error(conn, http_status, "Operation failed");
  }
}


static void
put_file(struct mg_connection *conn, const char *path)
{
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  const char *range;
  int64_t r1, r2;
  int rc;

  if (conn == NULL) {
    return;
  }

  DEBUG_TRACE("store %s", path);

  if (mg_stat(conn, path, &file.stat)) {
    /* File already exists */
    conn->status_code = 200;

    if (file.stat.is_directory) {
      /* This is an already existing directory,
       * so there is nothing to do for the server. */
      rc = 0;

    } else {
      /* File exists and is not a directory. */
      /* Can it be replaced? */

      /* Check if the server may write this file */
      if (access(path, W_OK) == 0) {
        /* Access granted */
        rc = 1;
      } else {
        mg_send_http_error(
            conn,
            403,
            "Error: Put not possible\nReplacing %s is not allowed",
            path);
        return;
      }
    }
  } else {
    /* File should be created */
    conn->status_code = 201;
    rc = put_dir(conn, path);
  }

  if (rc == 0) {
    /* put_dir returns 0 if path is a directory */

    /* Create response */
    mg_response_header_start(conn, conn->status_code);
    send_no_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn, "Content-Length", "0", -1);

    /* Send all headers - there is no body */
    mg_response_header_send(conn);

    /* Request to create a directory has been fulfilled successfully.
     * No need to put a file. */
    return;
  }

  if (rc == -1) {
    /* put_dir returns -1 if the path is too long */
    mg_send_http_error(conn,
                       414,
                       "Error: Path too long\nput_dir(%s): %s",
                       path,
                       strerror(ERRNO));
    return;
  }

  if (rc == -2) {
    /* put_dir returns -2 if the directory can not be created */
    mg_send_http_error(conn,
                       500,
                       "Error: Can not create directory\nput_dir(%s): %s",
                       path,
                       strerror(ERRNO));
    return;
  }

  /* A file should be created or overwritten. */
  /* Currently CivetWeb does not need read+write access. */
  if (!mg_fopen(conn, path, MG_FOPEN_MODE_WRITE, &file)
      || file.access.fp == NULL) {
    (void)mg_fclose(&file.access);
    mg_send_http_error(conn,
                       500,
                       "Error: Can not create file\nfopen(%s): %s",
                       path,
                       strerror(ERRNO));
    return;
  }

  fclose_on_exec(&file.access, conn);
  range = mg_get_header(conn, "Content-Range");
  r1 = r2 = 0;
  if ((range != NULL) && parse_range_header(range, &r1, &r2) > 0) {
    conn->status_code = 206; /* Partial content */
    if (0 != fseeko(file.access.fp, r1, SEEK_SET)) {
      mg_send_http_error(conn,
                         500,
                         "Error: Internal error processing file %s",
                         path);
      return;
    }
  }

  if (!forward_body_data(conn, file.access.fp, INVALID_SOCKET, NULL)) {
    /* forward_body_data failed.
     * The error code has already been sent to the client,
     * and conn->status_code is already set. */
    (void)mg_fclose(&file.access);
    return;
  }

  if (mg_fclose(&file.access) != 0) {
    /* fclose failed. This might have different reasons, but a likely
     * one is "no space on disk", http 507. */
    conn->status_code = 507;
  }

  /* Create response (status_code has been set before) */
  mg_response_header_start(conn, conn->status_code);
  send_no_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn, "Content-Length", "0", -1);

  /* Send all headers - there is no body */
  mg_response_header_send(conn);
}


static void
delete_file(struct mg_connection *conn, const char *path)
{
  struct de de;
  memset(&de.file, 0, sizeof(de.file));
  if (!mg_stat(conn, path, &de.file)) {
    /* mg_stat returns 0 if the file does not exist */
    mg_send_http_error(conn,
                       404,
                       "Error: Cannot delete file\nFile %s not found",
                       path);
    return;
  }

  DEBUG_TRACE("delete %s", path);

  if (de.file.is_directory) {
    if (remove_directory(conn, path)) {
      /* Delete is successful: Return 204 without content. */
      mg_send_http_error(conn, 204, "%s", "");
    } else {
      /* Delete is not successful: Return 500 (Server error). */
      mg_send_http_error(conn, 500, "Error: Could not delete %s", path);
    }
    return;
  }

  /* This is an existing file (not a directory).
   * Check if write permission is granted. */
  if (access(path, W_OK) != 0) {
    /* File is read only */
    mg_send_http_error(
        conn,
        403,
        "Error: Delete not possible\nDeleting %s is not allowed",
        path);
    return;
  }

  /* Try to delete it. */
  if (mg_remove(conn, path) == 0) {
    /* Delete was successful: Return 204 without content. */
    mg_response_header_start(conn, 204);
    send_no_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn, "Content-Length", "0", -1);
    mg_response_header_send(conn);

  } else {
    /* Delete not successful (file locked). */
    mg_send_http_error(conn,
                       423,
                       "Error: Cannot delete file\nremove(%s): %s",
                       path,
                       strerror(ERRNO));
  }
}
#endif /* !NO_FILES */


#if !defined(NO_FILESYSTEMS)
static void
send_ssi_file(struct mg_connection *, const char *, struct mg_file *, int);


static void
do_ssi_include(struct mg_connection *conn,
               const char *ssi,
               char *tag,
               int include_level)
{
  char file_name[MG_BUF_LEN], path[512], *p;
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  size_t len;
  int truncated = 0;

  if (conn == NULL) {
    return;
  }

  /* sscanf() is safe here, since send_ssi_file() also uses buffer
   * of size MG_BUF_LEN to get the tag. So strlen(tag) is
   * always < MG_BUF_LEN. */
  if (sscanf(tag, " virtual=\"%511[^\"]\"", file_name) == 1) {
    /* File name is relative to the webserver root */
    file_name[511] = 0;
    (void)mg_snprintf(conn,
                      &truncated,
                      path,
                      sizeof(path),
                      "%s/%s",
                      conn->dom_ctx->config[DOCUMENT_ROOT],
                      file_name);

  } else if (sscanf(tag, " abspath=\"%511[^\"]\"", file_name) == 1) {
    /* File name is relative to the webserver working directory
     * or it is absolute system path */
    file_name[511] = 0;
    (void)
        mg_snprintf(conn, &truncated, path, sizeof(path), "%s", file_name);

  } else if ((sscanf(tag, " file=\"%511[^\"]\"", file_name) == 1)
             || (sscanf(tag, " \"%511[^\"]\"", file_name) == 1)) {
    /* File name is relative to the current document */
    file_name[511] = 0;
    (void)mg_snprintf(conn, &truncated, path, sizeof(path), "%s", ssi);

    if (!truncated) {
      if ((p = strrchr(path, '/')) != NULL) {
        p[1] = '\0';
      }
      len = strlen(path);
      (void)mg_snprintf(conn,
                        &truncated,
                        path + len,
                        sizeof(path) - len,
                        "%s",
                        file_name);
    }

  } else {
    mg_cry_internal(conn, "Bad SSI #include: [%s]", tag);
    return;
  }

  if (truncated) {
    mg_cry_internal(conn, "SSI #include path length overflow: [%s]", tag);
    return;
  }

  if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, &file)) {
    mg_cry_internal(conn,
                    "Cannot open SSI #include: [%s]: fopen(%s): %s",
                    tag,
                    path,
                    strerror(ERRNO));
  } else {
    fclose_on_exec(&file.access, conn);
    if (match_prefix_strlen(conn->dom_ctx->config[SSI_EXTENSIONS], path)
        > 0) {
      send_ssi_file(conn, path, &file, include_level + 1);
    } else {
      send_file_data(conn, &file, 0, INT64_MAX, 0); /* send static file */
    }
    (void)mg_fclose(&file.access); /* Ignore errors for readonly files */
  }
}


#if !defined(NO_POPEN)
static void
do_ssi_exec(struct mg_connection *conn, char *tag)
{
  char cmd[1024] = "";
  struct mg_file file = STRUCT_FILE_INITIALIZER;

  if (sscanf(tag, " \"%1023[^\"]\"", cmd) != 1) {
    mg_cry_internal(conn, "Bad SSI #exec: [%s]", tag);
  } else {
    cmd[1023] = 0;
    if ((file.access.fp = popen(cmd, "r")) == NULL) {
      mg_cry_internal(conn,
                      "Cannot SSI #exec: [%s]: %s",
                      cmd,
                      strerror(ERRNO));
    } else {
      send_file_data(conn, &file, 0, INT64_MAX, 0); /* send static file */
      pclose(file.access.fp);
    }
  }
}
#endif /* !NO_POPEN */


static int
mg_fgetc(struct mg_file *filep)
{
  if (filep == NULL) {
    return EOF;
  }

  if (filep->access.fp != NULL) {
    return fgetc(filep->access.fp);
  } else {
    return EOF;
  }
}


static void
send_ssi_file(struct mg_connection *conn,
              const char *path,
              struct mg_file *filep,
              int include_level)
{
  char buf[MG_BUF_LEN];
  int ch, len, in_tag, in_ssi_tag;

  if (include_level > 10) {
    mg_cry_internal(conn, "SSI #include level is too deep (%s)", path);
    return;
  }

  in_tag = in_ssi_tag = len = 0;

  /* Read file, byte by byte, and look for SSI include tags */
  while ((ch = mg_fgetc(filep)) != EOF) {

    if (in_tag) {
      /* We are in a tag, either SSI tag or html tag */

      if (ch == '>') {
        /* Tag is closing */
        buf[len++] = '>';

        if (in_ssi_tag) {
          /* Handle SSI tag */
          buf[len] = 0;

          if ((len > 12) && !memcmp(buf + 5, "include", 7)) {
            do_ssi_include(conn, path, buf + 12, include_level + 1);
#if !defined(NO_POPEN)
          } else if ((len > 9) && !memcmp(buf + 5, "exec", 4)) {
            do_ssi_exec(conn, buf + 9);
#endif /* !NO_POPEN */
          } else {
            mg_cry_internal(conn,
                            "%s: unknown SSI "
                            "command: \"%s\"",
                            path,
                            buf);
          }
          len = 0;
          in_ssi_tag = in_tag = 0;

        } else {
          /* Not an SSI tag */
          /* Flush buffer */
          (void)mg_write(conn, buf, (size_t)len);
          len = 0;
          in_tag = 0;
        }

      } else {
        /* Tag is still open */
        buf[len++] = (char)(ch & 0xff);

        if ((len == 5) && !memcmp(buf, "<!--#", 5)) {
          /* All SSI tags start with <!--# */
          in_ssi_tag = 1;
        }

        if ((len + 2) > (int)sizeof(buf)) {
          /* Tag to long for buffer */
          mg_cry_internal(conn, "%s: tag is too large", path);
          return;
        }
      }

    } else {

      /* We are not in a tag yet. */
      if (ch == '<') {
        /* Tag is opening */
        in_tag = 1;

        if (len > 0) {
          /* Flush current buffer.
           * Buffer is filled with "len" bytes. */
          (void)mg_write(conn, buf, (size_t)len);
        }
        /* Store the < */
        len = 1;
        buf[0] = '<';

      } else {
        /* No Tag */
        /* Add data to buffer */
        buf[len++] = (char)(ch & 0xff);
        /* Flush if buffer is full */
        if (len == (int)sizeof(buf)) {
          mg_write(conn, buf, (size_t)len);
          len = 0;
        }
      }
    }
  }

  /* Send the rest of buffered data */
  if (len > 0) {
    mg_write(conn, buf, (size_t)len);
  }
}


static void
handle_ssi_file_request(struct mg_connection *conn,
                        const char *path,
                        struct mg_file *filep)
{
  char date[64];
  time_t curtime = time(NULL);

  if ((conn == NULL) || (path == NULL) || (filep == NULL)) {
    return;
  }

  if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, filep)) {
    /* File exists (precondition for calling this function),
     * but can not be opened by the server. */
    mg_send_http_error(conn,
                       500,
                       "Error: Cannot read file\nfopen(%s): %s",
                       path,
                       strerror(ERRNO));
  } else {
    /* Set "must_close" for HTTP/1.x, since we do not know the
     * content length */
    conn->must_close = 1;
    gmt_time_string(date, sizeof(date), &curtime);
    fclose_on_exec(&filep->access, conn);

    /* 200 OK response */
    mg_response_header_start(conn, 200);
    send_no_cache_header(conn);
    send_additional_header(conn);
    send_cors_header(conn);
    mg_response_header_add(conn, "Content-Type", "text/html", -1);
    mg_response_header_send(conn);

    /* Header sent, now send body */
    send_ssi_file(conn, path, filep, 0);
    (void)mg_fclose(&filep->access); /* Ignore errors for readonly files */
  }
}
#endif /* NO_FILESYSTEMS */


#if !defined(NO_FILES)
static void
send_options(struct mg_connection *conn)
{
  if (!conn || !all_methods) {
    return;
  }

  /* We do not set a "Cache-Control" header here, but leave the default.
   * Since browsers do not send an OPTIONS request, we can not test the
   * effect anyway. */

  mg_response_header_start(conn, 200);
  mg_response_header_add(conn, "Content-Type", "text/html", -1);

  if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
    /* Use the same as before */
    mg_response_header_add(conn, "Allow", all_methods, -1);
    mg_response_header_add(conn, "DAV", "1", -1);
  } else {
    /* TODO: Check this later for HTTP/2 */
    mg_response_header_add(conn, "Allow", "GET, POST", -1);
  }
  send_additional_header(conn);
  mg_response_header_send(conn);
}


/* Writes PROPFIND properties for a collection element */
static int
print_props(struct mg_connection *conn,
            const char *uri,
            const char *name,
            struct mg_file_stat *filep)
{
  size_t i;
  char mtime[64];
  char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
  char *link_concat;
  size_t link_concat_len;

  if ((conn == NULL) || (uri == NULL) || (name == NULL) || (filep == NULL)) {
    return 0;
  }

  link_concat_len = strlen(uri) + strlen(name) + 1;
  link_concat = mg_malloc_ctx(link_concat_len, conn->phys_ctx);
  if (!link_concat) {
    return 0;
  }
  strcpy(link_concat, uri);
  strcat(link_concat, name);

  /* Get full link used in request */
  mg_construct_local_link(
      conn, link_buf, sizeof(link_buf), NULL, 0, link_concat);

  /*
  OutputDebugStringA("print_props:\n  uri: ");
  OutputDebugStringA(uri);
  OutputDebugStringA("\n  name: ");
  OutputDebugStringA(name);
  OutputDebugStringA("\n  link: ");
  OutputDebugStringA(link_buf);
  OutputDebugStringA("\n");
  */

  gmt_time_string(mtime, sizeof(mtime), &filep->last_modified);
  mg_printf(conn,
            "<d:response>"
            "<d:href>%s</d:href>"
            "<d:propstat>"
            "<d:prop>"
            "<d:resourcetype>%s</d:resourcetype>"
            "<d:getcontentlength>%" INT64_FMT "</d:getcontentlength>"
            "<d:getlastmodified>%s</d:getlastmodified>"
            "<d:lockdiscovery>",
            link_buf,
            filep->is_directory ? "<d:collection/>" : "",
            filep->size,
            mtime);

  for (i = 0; i < NUM_WEBDAV_LOCKS; i++) {
    struct twebdav_lock *dav_lock = conn->phys_ctx->webdav_lock;
    if (!strcmp(dav_lock[i].path, link_buf)) {
      mg_printf(conn,
                "<d:activelock>"
                "<d:locktype><d:write/></d:locktype>"
                "<d:lockscope><d:exclusive/></d:lockscope>"
                "<d:depth>0</d:depth>"
                "<d:owner>%s</d:owner>"
                "<d:timeout>Second-%u</d:timeout>"
                "<d:locktoken>"
                "<d:href>%s</d:href>"
                "</d:locktoken>"
                "</d:activelock>\n",
                dav_lock[i].user,
                (unsigned)LOCK_DURATION_S,
                dav_lock[i].token);
    }
  }

  mg_printf(conn,
            "</d:lockdiscovery>"
            "</d:prop>"
            "<d:status>HTTP/1.1 200 OK</d:status>"
            "</d:propstat>"
            "</d:response>\n");

  mg_free(link_concat);
  return 1;
}


static int
print_dav_dir_entry(struct de *de, void *data)
{
  struct mg_connection *conn = (struct mg_connection *)data;
  if (!de || !conn
      || !print_props(
             conn, conn->request_info.local_uri, de->file_name, &de->file)) {
    /* stop scan */
    return 1;
  }
  return 0;
}


static void
handle_propfind(struct mg_connection *conn,
                const char *path,
                struct mg_file_stat *filep)
{
  const char *depth = mg_get_header(conn, "Depth");

  if (!conn || !path || !filep || !conn->dom_ctx) {
    return;
  }

  /* return 207 "Multi-Status" */
  conn->must_close = 1;
  mg_response_header_start(conn, 207);
  send_static_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn,
                         "Content-Type",
                         "application/xml; charset=utf-8",
                         -1);
  mg_response_header_send(conn);

  /* Content */
  mg_printf(conn,
            "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
            "<d:multistatus xmlns:d='DAV:'>\n");

  /* Print properties for the requested resource itself */
  print_props(conn, conn->request_info.local_uri, "", filep);

  /* If it is a directory, print directory entries too if Depth is not 0
   */
  if (filep->is_directory
      && !mg_strcasecmp(conn->dom_ctx->config[ENABLE_DIRECTORY_LISTING],
                        "yes")
      && ((depth == NULL) || (strcmp(depth, "0") != 0))) {
    scan_directory(conn, path, conn, &print_dav_dir_entry);
  }

  mg_printf(conn, "%s\n", "</d:multistatus>");
}


static void
dav_lock_file(struct mg_connection *conn, const char *path)
{
  /* internal function - therefore conn is assumed to be valid */
  char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
  uint64_t new_locktime;
  int lock_index = -1;
  int i;
  uint64_t LOCK_DURATION_NS =
      (uint64_t)(LOCK_DURATION_S) * (uint64_t)1000000000;
  struct twebdav_lock *dav_lock = conn->phys_ctx->webdav_lock;

  if (!path || !conn->dom_ctx || !conn->request_info.remote_user) {
    return;
  }
  mg_get_request_link(conn, link_buf, sizeof(link_buf));

  /* const char *refresh = mg_get_header(conn, "If"); */
  /* Link refresh should have an "If" header:
   * http://www.webdav.org/specs/rfc2518.html#n-example---refreshing-a-write-lock
   * But it seems Windows Explorer does not send them.
   */

  mg_lock_context(conn->phys_ctx);
  new_locktime = mg_get_current_time_ns();

  /* Find a slot for a lock */
  while (lock_index < 0) {
    /* find existing lock */
    for (i = 0; i < NUM_WEBDAV_LOCKS; i++) {
      if (!strcmp(dav_lock[i].path, link_buf)) {
        if (!strcmp(conn->request_info.remote_user, dav_lock[i].user)) {
          /* locked by the same user */
          dav_lock[i].locktime = new_locktime;
          lock_index = i;
          break;
        } else {
          /* already locked by someone else */
          if (new_locktime
              > (dav_lock[i].locktime + LOCK_DURATION_NS)) {
            /* Lock expired */
            dav_lock[i].path[0] = 0;
          } else {
            /* Lock still valid */
            mg_unlock_context(conn->phys_ctx);
            mg_send_http_error(conn, 423, "%s", "Already locked");
            return;
          }
        }
      }
    }

    /* create new lock token */
    for (i = 0; i < NUM_WEBDAV_LOCKS; i++) {
      if (dav_lock[i].path[0] == 0) {
        char s[32];
        dav_lock[i].locktime = mg_get_current_time_ns();
        sprintf(s, "%" UINT64_FMT, (uint64_t)dav_lock[i].locktime);
        mg_md5(dav_lock[i].token,
               link_buf,
               "\x01",
               s,
               "\x01",
               conn->request_info.remote_user,
               NULL);
        mg_strlcpy(dav_lock[i].path,
                   link_buf,
                   sizeof(dav_lock[i].path));
        mg_strlcpy(dav_lock[i].user,
                   conn->request_info.remote_user,
                   sizeof(dav_lock[i].user));
        lock_index = i;
        break;
      }
    }
    if (lock_index < 0) {
      /* too many locks. Find oldest lock */
      uint64_t oldest_locktime = dav_lock[0].locktime;
      lock_index = 0;
      for (i = 1; i < NUM_WEBDAV_LOCKS; i++) {
        if (dav_lock[i].locktime < oldest_locktime) {
          oldest_locktime = dav_lock[i].locktime;
          lock_index = i;
        }
      }
      /* invalidate oldest lock */
      dav_lock[lock_index].path[0] = 0;
    }
  }
  mg_unlock_context(conn->phys_ctx);

  /* return 200 "OK" */
  conn->must_close = 1;
  mg_response_header_start(conn, 200);
  send_static_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn,
                         "Content-Type",
                         "application/xml; charset=utf-8",
                         -1);
  mg_response_header_add(conn, "Lock-Token", dav_lock[lock_index].token, -1);
  mg_response_header_send(conn);

  /* Content */
  mg_printf(conn,
            "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
            "<d:prop xmlns:d=\"DAV:\">\n"
            "     <d:lockdiscovery>\n"
            "       <d:activelock>\n"
            "         <d:lockscope><d:exclusive/></d:lockscope>\n"
            "         <d:locktype><d:write/></d:locktype>\n"
            "         <d:owner>\n"
            "           <d:href>%s</d:href>\n"
            "         </d:owner>\n"
            "         <d:timeout>Second-%u</d:timeout>\n"
            "         <d:locktoken><d:href>%s</d:href></d:locktoken>\n"
            "         <d:lockroot>\n"
            "           <d:href>%s</d:href>\n"
            "         </d:lockroot>\n"
            "       </d:activelock>\n"
            "     </d:lockdiscovery>\n"
            "   </d:prop>\n",
            dav_lock[lock_index].user,
            (LOCK_DURATION_S),
            dav_lock[lock_index].token,
            dav_lock[lock_index].path);
}


static void
dav_unlock_file(struct mg_connection *conn, const char *path)
{
  /* internal function - therefore conn is assumed to be valid */
  char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
  struct twebdav_lock *dav_lock = conn->phys_ctx->webdav_lock;
  int lock_index;

  if (!path || !conn->dom_ctx || !conn->request_info.remote_user) {
    return;
  }

  mg_get_request_link(conn, link_buf, sizeof(link_buf));

  mg_lock_context(conn->phys_ctx);
  /* find existing lock */
  for (lock_index = 0; lock_index < NUM_WEBDAV_LOCKS; lock_index++) {
    if (!strcmp(dav_lock[lock_index].path, link_buf)) {
      /* Success: return 204 "No Content" */
      mg_unlock_context(conn->phys_ctx);
      conn->must_close = 1;
      mg_response_header_start(conn, 204);
      mg_response_header_send(conn);
      return;
    }
  }
  mg_unlock_context(conn->phys_ctx);

  /* Error: Cannot unlock a resource that is not locked */
  mg_send_http_error(conn, 423, "%s", "Lock not found");
}


static void
dav_proppatch(struct mg_connection *conn, const char *path)
{
  char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */

  if (!conn || !path || !conn->dom_ctx) {
    return;
  }

  /* return 207 "Multi-Status" */
  conn->must_close = 1;
  mg_response_header_start(conn, 207);
  send_static_cache_header(conn);
  send_additional_header(conn);
  mg_response_header_add(conn,
                         "Content-Type",
                         "application/xml; charset=utf-8",
                         -1);
  mg_response_header_send(conn);

  mg_get_request_link(conn, link_buf, sizeof(link_buf));

  /* Content */
  mg_printf(conn,
            "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
            "<d:multistatus xmlns:d='DAV:'>\n"
            "<d:response>\n<d:href>%s</d:href>\n",
            link_buf);
  mg_printf(conn,
            "<d:propstat><d:status>HTTP/1.1 403 "
            "Forbidden</d:status></d:propstat>\n");
  mg_printf(conn, "%s\n", "</d:response></d:multistatus>");
}
#endif


CIVETWEB_API void
mg_lock_connection(struct mg_connection *conn)
{
  if (conn) {
    (void)pthread_mutex_lock(&conn->mutex);
  }
}


CIVETWEB_API void
mg_unlock_connection(struct mg_connection *conn)
{
  if (conn) {
    (void)pthread_mutex_unlock(&conn->mutex);
  }
}


CIVETWEB_API void
mg_lock_context(struct mg_context *ctx)
{
  if (ctx && (ctx->context_type == CONTEXT_SERVER)) {
    (void)pthread_mutex_lock(&ctx->nonce_mutex);
  }
}


CIVETWEB_API void
mg_unlock_context(struct mg_context *ctx)
{
  if (ctx && (ctx->context_type == CONTEXT_SERVER)) {
    (void)pthread_mutex_unlock(&ctx->nonce_mutex);
  }
}


#if defined(USE_LUA)
#include "mod_lua.inl"
#endif /* USE_LUA */

#if defined(USE_DUKTAPE)
#include "mod_duktape.inl"
#endif /* USE_DUKTAPE */

#if defined(USE_WEBSOCKET)

#if !defined(NO_SSL_DL)
#if !defined(OPENSSL_API_3_0)
#define SHA_API static
#include "sha1.inl"
#endif
#endif

static int
send_websocket_handshake(struct mg_connection *conn, const char *websock_key)
{
  static const char *magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
  char buf[100], sha[20], b64_sha[sizeof(sha) * 2];
  size_t dst_len = sizeof(b64_sha);
#if !defined(OPENSSL_API_3_0)
  SHA_CTX sha_ctx;
#endif
  int truncated;

  /* Calculate Sec-WebSocket-Accept reply from Sec-WebSocket-Key. */
  mg_snprintf(conn, &truncated, buf, sizeof(buf), "%s%s", websock_key, magic);
  if (truncated) {
    conn->must_close = 1;
    return 0;
  }

  DEBUG_TRACE("%s", "Send websocket handshake");

#if defined(OPENSSL_API_3_0)
  EVP_Digest((unsigned char *)buf,
             (uint32_t)strlen(buf),
             (unsigned char *)sha,
             NULL,
             EVP_get_digestbyname("sha1"),
             NULL);
#else
  SHA1_Init(&sha_ctx);
  SHA1_Update(&sha_ctx, (unsigned char *)buf, (uint32_t)strlen(buf));
  SHA1_Final((unsigned char *)sha, &sha_ctx);
#endif
  mg_base64_encode((unsigned char *)sha, sizeof(sha), b64_sha, &dst_len);
  mg_printf(conn,
            "HTTP/1.1 101 Switching Protocols\r\n"
            "Upgrade: websocket\r\n"
            "Connection: Upgrade\r\n"
            "Sec-WebSocket-Accept: %s\r\n",
            b64_sha);

#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
  // Send negotiated compression extension parameters
  websocket_deflate_response(conn);
#endif

  if (conn->request_info.acceptedWebSocketSubprotocol) {
    mg_printf(conn,
              "Sec-WebSocket-Protocol: %s\r\n\r\n",
              conn->request_info.acceptedWebSocketSubprotocol);
  } else {
    mg_printf(conn, "%s", "\r\n");
  }

  return 1;
}


#if !defined(MG_MAX_UNANSWERED_PING)
/* Configuration of the maximum number of websocket PINGs that might
 * stay unanswered before the connection is considered broken.
 * Note: The name of this define may still change (until it is
 * defined as a compile parameter in a documentation).
 */
#define MG_MAX_UNANSWERED_PING (5)
#endif


static void
read_websocket(struct mg_connection *conn,
               mg_websocket_data_handler ws_data_handler,
               void *callback_data)
{
  /* Pointer to the beginning of the portion of the incoming websocket
   * message queue.
   * The original websocket upgrade request is never removed, so the queue
   * begins after it. */
  unsigned char *buf = (unsigned char *)conn->buf + conn->request_len;
  int n, error, exit_by_callback;
  int ret;

  /* body_len is the length of the entire queue in bytes
   * len is the length of the current message
   * data_len is the length of the current message's data payload
   * header_len is the length of the current message's header */
  size_t i, len, mask_len = 0, header_len, body_len;
  uint64_t data_len = 0;

  /* "The masking key is a 32-bit value chosen at random by the client."
   * http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17#section-5
   */
  unsigned char mask[4];

  /* data points to the place where the message is stored when passed to
   * the websocket_data callback.  This is either mem on the stack, or a
   * dynamically allocated buffer if it is too large. */
  unsigned char mem[4096];
  unsigned char mop; /* mask flag and opcode */

  /* Variables used for connection monitoring */
  double timeout = -1.0;
  int enable_ping_pong = 0;
  int ping_count = 0;

  if (conn->dom_ctx->config[ENABLE_WEBSOCKET_PING_PONG]) {
    enable_ping_pong =
        !mg_strcasecmp(conn->dom_ctx->config[ENABLE_WEBSOCKET_PING_PONG],
                       "yes");
  }

  if (conn->dom_ctx->config[WEBSOCKET_TIMEOUT]) {
    timeout = atoi(conn->dom_ctx->config[WEBSOCKET_TIMEOUT]) / 1000.0;
  }
  if ((timeout <= 0.0) && (conn->dom_ctx->config[REQUEST_TIMEOUT])) {
    timeout = atoi(conn->dom_ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }
  if (timeout <= 0.0) {
    timeout = atof(config_options[REQUEST_TIMEOUT].default_value) / 1000.0;
  }

  /* Enter data processing loop */
  DEBUG_TRACE("Websocket connection %s:%u start data processing loop",
              conn->request_info.remote_addr,
              conn->request_info.remote_port);
  conn->in_websocket_handling = 1;
  mg_set_thread_name("wsock");

  /* Loop continuously, reading messages from the socket, invoking the
   * callback, and waiting repeatedly until an error occurs. */
  while (STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)
         && (!conn->must_close)) {
    header_len = 0;
    DEBUG_ASSERT(conn->data_len >= conn->request_len);
    if ((body_len = (size_t)(conn->data_len - conn->request_len)) >= 2) {
      len = buf[1] & 127;
      mask_len = (buf[1] & 128) ? 4 : 0;
      if ((len < 126) && (body_len >= mask_len)) {
        /* inline 7-bit length field */
        data_len = len;
        header_len = 2 + mask_len;
      } else if ((len == 126) && (body_len >= (4 + mask_len))) {
        /* 16-bit length field */
        header_len = 4 + mask_len;
        data_len = ((((size_t)buf[2]) << 8) + buf[3]);
      } else if (body_len >= (10 + mask_len)) {
        /* 64-bit length field */
        uint32_t l1, l2;
        memcpy(&l1, &buf[2], 4); /* Use memcpy for alignment */
        memcpy(&l2, &buf[6], 4);
        header_len = 10 + mask_len;
        data_len = (((uint64_t)ntohl(l1)) << 32) + ntohl(l2);

        if (data_len > (uint64_t)0x7FFF0000ul) {
          /* no can do */
          mg_cry_internal(
              conn,
              "%s",
              "websocket out of memory; closing connection");
          break;
        }
      }
    }

    if ((header_len > 0) && (body_len >= header_len)) {
      /* Allocate space to hold websocket payload */
      unsigned char *data = mem;

      if ((size_t)data_len > (size_t)sizeof(mem)) {
        data = (unsigned char *)mg_malloc_ctx((size_t)data_len,
                                              conn->phys_ctx);
        if (data == NULL) {
          /* Allocation failed, exit the loop and then close the
           * connection */
          mg_cry_internal(
              conn,
              "%s",
              "websocket out of memory; closing connection");
          break;
        }
      }

      /* Copy the mask before we shift the queue and destroy it */
      if (mask_len > 0) {
        memcpy(mask, buf + header_len - mask_len, sizeof(mask));
      } else {
        memset(mask, 0, sizeof(mask));
      }

      /* Read frame payload from the first message in the queue into
       * data and advance the queue by moving the memory in place. */
      DEBUG_ASSERT(body_len >= header_len);
      if (data_len + (uint64_t)header_len > (uint64_t)body_len) {
        mop = buf[0]; /* current mask and opcode */
                      /* Overflow case */
        len = body_len - header_len;
        memcpy(data, buf + header_len, len);
        error = 0;
        while ((uint64_t)len < data_len) {
          n = pull_inner(NULL,
                         conn,
                         (char *)(data + len),
                         (int)(data_len - len),
                         timeout);
          if (n <= -2) {
            error = 1;
            break;
          } else if (n > 0) {
            len += (size_t)n;
          } else {
            /* Timeout: should retry */
            /* TODO: retry condition */
          }
        }
        if (error) {
          mg_cry_internal(
              conn,
              "%s",
              "Websocket pull failed; closing connection");
          if (data != mem) {
            mg_free(data);
          }
          break;
        }

        conn->data_len = conn->request_len;

      } else {

        mop = buf[0]; /* current mask and opcode, overwritten by
                       * memmove() */

        /* Length of the message being read at the front of the
         * queue. Cast to 31 bit is OK, since we limited
         * data_len before. */
        len = (size_t)data_len + header_len;

        /* Copy the data payload into the data pointer for the
         * callback. Cast to 31 bit is OK, since we
         * limited data_len */
        memcpy(data, buf + header_len, (size_t)data_len);

        /* Move the queue forward len bytes */
        memmove(buf, buf + len, body_len - len);

        /* Mark the queue as advanced */
        conn->data_len -= (int)len;
      }

      /* Apply mask if necessary */
      if (mask_len > 0) {
        for (i = 0; i < (size_t)data_len; i++) {
          data[i] ^= mask[i & 3];
        }
      }

      exit_by_callback = 0;
      if (enable_ping_pong && ((mop & 0xF) == MG_WEBSOCKET_OPCODE_PONG)) {
        /* filter PONG messages */
        DEBUG_TRACE("PONG from %s:%u",
                    conn->request_info.remote_addr,
                    conn->request_info.remote_port);
        /* No unanwered PINGs left */
        ping_count = 0;
      } else if (enable_ping_pong
                 && ((mop & 0xF) == MG_WEBSOCKET_OPCODE_PING)) {
        /* reply PING messages */
        DEBUG_TRACE("Reply PING from %s:%u",
                    conn->request_info.remote_addr,
                    conn->request_info.remote_port);
        ret = mg_websocket_write(conn,
                                 MG_WEBSOCKET_OPCODE_PONG,
                                 (char *)data,
                                 (size_t)data_len);
        if (ret <= 0) {
          /* Error: send failed */
          DEBUG_TRACE("Reply PONG failed (%i)", ret);
          break;
        }

      } else {
        /* Exit the loop if callback signals to exit (server side),
         * or "connection close" opcode received (client side). */
        if (ws_data_handler != NULL) {
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
          if (mop & 0x40) {
            /* Inflate the data received if bit RSV1 is set. */
            if (!conn->websocket_deflate_initialized) {
              if (websocket_deflate_initialize(conn, 1) != Z_OK)
                exit_by_callback = 1;
            }
            if (!exit_by_callback) {
              size_t inflate_buf_size_old = 0;
              size_t inflate_buf_size =
                  data_len
                  * 4; // Initial guess of the inflated message
                       // size. We double the memory when needed.
              Bytef *inflated = NULL;
              Bytef *new_mem = NULL;
              conn->websocket_inflate_state.avail_in =
                  (uInt)(data_len + 4);
              conn->websocket_inflate_state.next_in = data;
              // Add trailing 0x00 0x00 0xff 0xff bytes
              data[data_len] = '\x00';
              data[data_len + 1] = '\x00';
              data[data_len + 2] = '\xff';
              data[data_len + 3] = '\xff';
              do {
                if (inflate_buf_size_old == 0) {
                  new_mem =
                      (Bytef *)mg_calloc(inflate_buf_size,
                                         sizeof(Bytef));
                } else {
                  inflate_buf_size *= 2;
                  new_mem =
                      (Bytef *)mg_realloc(inflated,
                                          inflate_buf_size);
                }
                if (new_mem == NULL) {
                  mg_cry_internal(
                      conn,
                      "Out of memory: Cannot allocate "
                      "inflate buffer of %lu bytes",
                      (unsigned long)inflate_buf_size);
                  exit_by_callback = 1;
                  break;
                }
                inflated = new_mem;
                conn->websocket_inflate_state.avail_out =
                    (uInt)(inflate_buf_size
                           - inflate_buf_size_old);
                conn->websocket_inflate_state.next_out =
                    inflated + inflate_buf_size_old;
                ret = inflate(&conn->websocket_inflate_state,
                              Z_SYNC_FLUSH);
                if (ret == Z_NEED_DICT || ret == Z_DATA_ERROR
                    || ret == Z_MEM_ERROR) {
                  mg_cry_internal(
                      conn,
                      "ZLIB inflate error: %i %s",
                      ret,
                      (conn->websocket_inflate_state.msg
                           ? conn->websocket_inflate_state.msg
                           : "<no error message>"));
                  exit_by_callback = 1;
                  break;
                }
                inflate_buf_size_old = inflate_buf_size;

              } while (conn->websocket_inflate_state.avail_out
                       == 0);
              inflate_buf_size -=
                  conn->websocket_inflate_state.avail_out;
              if (!ws_data_handler(conn,
                                   mop,
                                   (char *)inflated,
                                   inflate_buf_size,
                                   callback_data)) {
                exit_by_callback = 1;
              }
              mg_free(inflated);
            }
          } else
#endif
              if (!ws_data_handler(conn,
                                   mop,
                                   (char *)data,
                                   (size_t)data_len,
                                   callback_data)) {
            exit_by_callback = 1;
          }
        }
      }

      /* It a buffer has been allocated, free it again */
      if (data != mem) {
        mg_free(data);
      }

      if (exit_by_callback) {
        DEBUG_TRACE("Callback requests to close connection from %s:%u",
                    conn->request_info.remote_addr,
                    conn->request_info.remote_port);
        break;
      }
      if ((mop & 0xf) == MG_WEBSOCKET_OPCODE_CONNECTION_CLOSE) {
        /* Opcode == 8, connection close */
        DEBUG_TRACE("Message requests to close connection from %s:%u",
                    conn->request_info.remote_addr,
                    conn->request_info.remote_port);
        break;
      }

      /* Not breaking the loop, process next websocket frame. */
    } else {
      /* Read from the socket into the next available location in the
       * message queue. */
      n = pull_inner(NULL,
                     conn,
                     conn->buf + conn->data_len,
                     conn->buf_size - conn->data_len,
                     timeout);
      if (n <= -2) {
        /* Error, no bytes read */
        DEBUG_TRACE("PULL from %s:%u failed",
                    conn->request_info.remote_addr,
                    conn->request_info.remote_port);
        break;
      }
      if (n > 0) {
        conn->data_len += n;
        /* Reset open PING count */
        ping_count = 0;
      } else {
        if (STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)
            && (!conn->must_close)) {
          if (ping_count > MG_MAX_UNANSWERED_PING) {
            /* Stop sending PING */
            DEBUG_TRACE("Too many (%i) unanswered ping from %s:%u "
                        "- closing connection",
                        ping_count,
                        conn->request_info.remote_addr,
                        conn->request_info.remote_port);
            break;
          }
          if (enable_ping_pong) {
            /* Send Websocket PING message */
            DEBUG_TRACE("PING to %s:%u",
                        conn->request_info.remote_addr,
                        conn->request_info.remote_port);
            ret = mg_websocket_write(conn,
                                     MG_WEBSOCKET_OPCODE_PING,
                                     NULL,
                                     0);

            if (ret <= 0) {
              /* Error: send failed */
              DEBUG_TRACE("Send PING failed (%i)", ret);
              break;
            }
            ping_count++;
          }
        }
        /* Timeout: should retry */
        /* TODO: get timeout def */
      }
    }
  }

  /* Leave data processing loop */
  mg_set_thread_name("worker");
  conn->in_websocket_handling = 0;
  DEBUG_TRACE("Websocket connection %s:%u left data processing loop",
              conn->request_info.remote_addr,
              conn->request_info.remote_port);
}


static int
mg_websocket_write_exec(struct mg_connection *conn,
                        int opcode,
                        const char *data,
                        size_t dataLen,
                        uint32_t masking_key)
{
  unsigned char header[14];
  size_t headerLen;
  int retval;

#if defined(GCC_DIAGNOSTIC)
  /* Disable spurious conversion warning for GCC */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wconversion"
#endif

  /* Note that POSIX/Winsock's send() is threadsafe
   * http://stackoverflow.com/questions/1981372/are-parallel-calls-to-send-recv-on-the-same-socket-valid
   * but mongoose's mg_printf/mg_write is not (because of the loop in
   * push(), although that is only a problem if the packet is large or
   * outgoing buffer is full). */

  /* TODO: Check if this lock should be moved to user land.
   * Currently the server sets this lock for websockets, but
   * not for any other connection. It must be set for every
   * conn read/written by more than one thread, no matter if
   * it is a websocket or regular connection. */
  (void)mg_lock_connection(conn);

#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
  size_t deflated_size = 0;
  Bytef *deflated = 0;
  // Deflate websocket messages over 100kb
  int use_deflate = dataLen > 100 * 1024 && conn->accept_gzip;

  if (use_deflate) {
    if (!conn->websocket_deflate_initialized) {
      if (websocket_deflate_initialize(conn, 1) != Z_OK)
        return 0;
    }

    // Deflating the message
    header[0] = 0xC0u | (unsigned char)((unsigned)opcode & 0xf);
    conn->websocket_deflate_state.avail_in = (uInt)dataLen;
    conn->websocket_deflate_state.next_in = (unsigned char *)data;
    deflated_size = (size_t)compressBound((uLong)dataLen);
    deflated = mg_calloc(deflated_size, sizeof(Bytef));
    if (deflated == NULL) {
      mg_cry_internal(
          conn,
          "Out of memory: Cannot allocate deflate buffer of %lu bytes",
          (unsigned long)deflated_size);
      mg_unlock_connection(conn);
      return -1;
    }
    conn->websocket_deflate_state.avail_out = (uInt)deflated_size;
    conn->websocket_deflate_state.next_out = deflated;
    deflate(&conn->websocket_deflate_state, conn->websocket_deflate_flush);
    dataLen = deflated_size - conn->websocket_deflate_state.avail_out
              - 4; // Strip trailing 0x00 0x00 0xff 0xff bytes
  } else
#endif
    header[0] = 0x80u | (unsigned char)((unsigned)opcode & 0xf);

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif

  /* Frame format: http://tools.ietf.org/html/rfc6455#section-5.2 */
  if (dataLen < 126) {
    /* inline 7-bit length field */
    header[1] = (unsigned char)dataLen;
    headerLen = 2;
  } else if (dataLen <= 0xFFFF) {
    /* 16-bit length field */
    uint16_t len = htons((uint16_t)dataLen);
    header[1] = 126;
    memcpy(header + 2, &len, 2);
    headerLen = 4;
  } else {
    /* 64-bit length field */
    uint32_t len1 = htonl((uint32_t)((uint64_t)dataLen >> 32));
    uint32_t len2 = htonl((uint32_t)(dataLen & 0xFFFFFFFFu));
    header[1] = 127;
    memcpy(header + 2, &len1, 4);
    memcpy(header + 6, &len2, 4);
    headerLen = 10;
  }

  if (masking_key) {
    /* add mask */
    header[1] |= 0x80;
    memcpy(header + headerLen, &masking_key, 4);
    headerLen += 4;
  }

  retval = mg_write(conn, header, headerLen);
  if (retval != (int)headerLen) {
    /* Did not send complete header */
    retval = -1;
  } else {
    if (dataLen > 0) {
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
      if (use_deflate) {
        retval = mg_write(conn, deflated, dataLen);
        mg_free(deflated);
      } else
#endif
        retval = mg_write(conn, data, dataLen);
    }
    /* if dataLen == 0, the header length (2) is returned */
  }

  /* TODO: Remove this unlock as well, when lock is removed. */
  mg_unlock_connection(conn);

  return retval;
}


CIVETWEB_API int
mg_websocket_write(struct mg_connection *conn,
                   int opcode,
                   const char *data,
                   size_t dataLen)
{
  return mg_websocket_write_exec(conn, opcode, data, dataLen, 0);
}


static void
mask_data(const char *in, size_t in_len, uint32_t masking_key, char *out)
{
  size_t i = 0;

  i = 0;
  if ((in_len > 3) && ((ptrdiff_t)in % 4) == 0) {
    /* Convert in 32 bit words, if data is 4 byte aligned */
    while (i < (in_len - 3)) {
      *(uint32_t *)(void *)(out + i) =
          *(uint32_t *)(void *)(in + i) ^ masking_key;
      i += 4;
    }
  }
  if (i != in_len) {
    /* convert 1-3 remaining bytes if ((dataLen % 4) != 0)*/
    while (i < in_len) {
      *(uint8_t *)(void *)(out + i) =
          *(uint8_t *)(void *)(in + i)
          ^ *(((uint8_t *)&masking_key) + (i % 4));
      i++;
    }
  }
}


CIVETWEB_API int
mg_websocket_client_write(struct mg_connection *conn,
                          int opcode,
                          const char *data,
                          size_t dataLen)
{
  int retval = -1;
  char *masked_data =
      (char *)mg_malloc_ctx(((dataLen + 7) / 4) * 4, conn->phys_ctx);
  uint32_t masking_key = 0;

  if (masked_data == NULL) {
    /* Return -1 in an error case */
    mg_cry_internal(conn,
                    "%s",
                    "Cannot allocate buffer for masked websocket response: "
                    "Out of memory");
    return -1;
  }

  do {
    /* Get a masking key - but not 0 */
    masking_key = (uint32_t)get_random();
  } while (masking_key == 0);

  mask_data(data, dataLen, masking_key, masked_data);

  retval = mg_websocket_write_exec(
      conn, opcode, masked_data, dataLen, masking_key);
  mg_free(masked_data);

  return retval;
}


static void
handle_websocket_request(struct mg_connection *conn,
                         const char *path,
                         int is_callback_resource,
                         struct mg_websocket_subprotocols *subprotocols,
                         mg_websocket_connect_handler ws_connect_handler,
                         mg_websocket_ready_handler ws_ready_handler,
                         mg_websocket_data_handler ws_data_handler,
                         mg_websocket_close_handler ws_close_handler,
                         void *cbData)
{
  const char *websock_key = mg_get_header(conn, "Sec-WebSocket-Key");
  const char *version = mg_get_header(conn, "Sec-WebSocket-Version");
  ptrdiff_t lua_websock = 0;

#if !defined(USE_LUA)
  (void)path;
#endif

  /* Step 1: Check websocket protocol version. */
  /* Step 1.1: Check Sec-WebSocket-Key. */
  if (!websock_key) {
    /* The RFC standard version (https://tools.ietf.org/html/rfc6455)
     * requires a Sec-WebSocket-Key header.
     */
    /* It could be the hixie draft version
     * (http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-76).
     */
    const char *key1 = mg_get_header(conn, "Sec-WebSocket-Key1");
    const char *key2 = mg_get_header(conn, "Sec-WebSocket-Key2");
    char key3[8];

    if ((key1 != NULL) && (key2 != NULL)) {
      /* This version uses 8 byte body data in a GET request */
      conn->content_len = 8;
      if (8 == mg_read(conn, key3, 8)) {
        /* This is the hixie version */
        mg_send_http_error(conn,
                           426,
                           "%s",
                           "Protocol upgrade to RFC 6455 required");
        return;
      }
    }
    /* This is an unknown version */
    mg_send_http_error(conn, 400, "%s", "Malformed websocket request");
    return;
  }

  /* Step 1.2: Check websocket protocol version. */
  /* The RFC version (https://tools.ietf.org/html/rfc6455) is 13. */
  if ((version == NULL) || (strcmp(version, "13") != 0)) {
    /* Reject wrong versions */
    mg_send_http_error(conn, 426, "%s", "Protocol upgrade required");
    return;
  }

  /* Step 1.3: Could check for "Host", but we do not really need this
   * value for anything, so just ignore it. */

  /* Step 2: If a callback is responsible, call it. */
  if (is_callback_resource) {
    /* Step 2.1 check and select subprotocol */
    const char *protocols[64]; // max 64 headers
    int nbSubprotocolHeader = get_req_headers(&conn->request_info,
                                              "Sec-WebSocket-Protocol",
                                              protocols,
                                              64);

    if ((nbSubprotocolHeader > 0) && subprotocols) {

      int headerNo, idx;
      size_t len;
      const char *sep, *curSubProtocol,
          *acceptedWebSocketSubprotocol = NULL;

      /* look for matching subprotocol */
      for (headerNo = 0; headerNo < nbSubprotocolHeader; headerNo++) {
        /* There might be multiple headers ... */
        const char *protocol = protocols[headerNo];
        curSubProtocol = protocol;

        /* ... and in every header there might be a , separated list */
        while (!acceptedWebSocketSubprotocol && (*curSubProtocol)) {

          while ((*curSubProtocol == ' ') || (*curSubProtocol == ','))
            curSubProtocol++;
          sep = strchr(curSubProtocol, ',');
          if (sep) {
            len = (size_t)(sep - curSubProtocol);
          } else {
            len = strlen(curSubProtocol);
          }

          for (idx = 0; idx < subprotocols->nb_subprotocols; idx++) {
            // COMPARE: curSubProtocol ==
            // subprotocols->subprotocols[idx]
            if ((strlen(subprotocols->subprotocols[idx]) == len)
                && (strncmp(curSubProtocol,
                            subprotocols->subprotocols[idx],
                            len)
                    == 0)) {
              acceptedWebSocketSubprotocol =
                  subprotocols->subprotocols[idx];
              break;
            }
          }
          curSubProtocol += len;
        }
      }

      conn->request_info.acceptedWebSocketSubprotocol =
          acceptedWebSocketSubprotocol;
    }

#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
    websocket_deflate_negotiate(conn);
#endif

    if ((ws_connect_handler != NULL)
        && (ws_connect_handler(conn, cbData) != 0)) {
      /* C callback has returned non-zero, do not proceed with
       * handshake.
       */
      /* Note that C callbacks are no longer called when Lua is
       * responsible, so C can no longer filter callbacks for Lua. */
      return;
    }
  }

#if defined(USE_LUA)
  /* Step 3: No callback. Check if Lua is responsible. */
  else {
    /* Step 3.1: Check if Lua is responsible. */
    if (conn->dom_ctx->config[LUA_WEBSOCKET_EXTENSIONS]) {
      lua_websock = match_prefix_strlen(
          conn->dom_ctx->config[LUA_WEBSOCKET_EXTENSIONS], path);
    }

    if (lua_websock > 0) {
      /* Step 3.2: Lua is responsible: call it. */
      conn->lua_websocket_state = lua_websocket_new(path, conn);
      if (!conn->lua_websocket_state) {
        /* Lua rejected the new client */
        return;
      }
    }
  }
#endif

  /* Step 4: Check if there is a responsible websocket handler. */
  if (!is_callback_resource && !lua_websock) {
    /* There is no callback, and Lua is not responsible either. */
    /* Reply with a 404 Not Found. We are still at a standard
     * HTTP request here, before the websocket handshake, so
     * we can still send standard HTTP error replies. */
    mg_send_http_error(conn, 404, "%s", "Not found");
    return;
  }

  /* Step 5: The websocket connection has been accepted */
  if (!send_websocket_handshake(conn, websock_key)) {
    mg_send_http_error(conn, 500, "%s", "Websocket handshake failed");
    return;
  }

  /* Step 6: Call the ready handler */
  if (is_callback_resource) {
    if (ws_ready_handler != NULL) {
      ws_ready_handler(conn, cbData);
    }
#if defined(USE_LUA)
  } else if (lua_websock) {
    if (!lua_websocket_ready(conn, conn->lua_websocket_state)) {
      /* the ready handler returned false */
      return;
    }
#endif
  }

  /* Step 7: Enter the read loop */
  if (is_callback_resource) {
    read_websocket(conn, ws_data_handler, cbData);
#if defined(USE_LUA)
  } else if (lua_websock) {
    read_websocket(conn, lua_websocket_data, conn->lua_websocket_state);
#endif
  }

#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
  /* Step 8: Close the deflate & inflate buffers */
  if (conn->websocket_deflate_initialized) {
    deflateEnd(&conn->websocket_deflate_state);
    inflateEnd(&conn->websocket_inflate_state);
  }
#endif

  /* Step 9: Call the close handler */
  if (ws_close_handler) {
    ws_close_handler(conn, cbData);
  }
}
#endif /* !USE_WEBSOCKET */


/* Is upgrade request:
 *   0 = regular HTTP/1.0 or HTTP/1.1 request
 *   1 = upgrade to websocket
 *   2 = upgrade to HTTP/2
 * -1 = upgrade to unknown protocol
 */
static int
should_switch_to_protocol(const struct mg_connection *conn)
{
  const char *connection_headers[8];
  const char *upgrade_to;
  int connection_header_count, i, should_upgrade;

  /* A websocket protocol has the following HTTP headers:
   *
   * Connection: Upgrade
   * Upgrade: Websocket
   *
   * It seems some clients use multiple headers:
   * see https://github.com/civetweb/civetweb/issues/1083
   */
  connection_header_count = get_req_headers(&conn->request_info,
                                            "Connection",
                                            connection_headers,
                                            8);
  should_upgrade = 0;
  for (i = 0; i < connection_header_count; i++) {
    if (0 != mg_strcasestr(connection_headers[i], "upgrade")) {
      should_upgrade = 1;
    }
  }
  if (!should_upgrade) {
    return PROTOCOL_TYPE_HTTP1;
  }

  upgrade_to = mg_get_header(conn, "Upgrade");
  if (upgrade_to == NULL) {
    /* "Connection: Upgrade" without "Upgrade" Header --> Error */
    return -1;
  }

  /* Upgrade to ... */
  if (0 != mg_strcasestr(upgrade_to, "websocket")) {
    /* The headers "Host", "Sec-WebSocket-Key", "Sec-WebSocket-Protocol" and
     * "Sec-WebSocket-Version" are also required.
     * Don't check them here, since even an unsupported websocket protocol
     * request still IS a websocket request (in contrast to a standard HTTP
     * request). It will fail later in handle_websocket_request.
     */
    return PROTOCOL_TYPE_WEBSOCKET; /* Websocket */
  }
  if (0 != mg_strcasestr(upgrade_to, "h2")) {
    return PROTOCOL_TYPE_HTTP2; /* Websocket */
  }

  /* Upgrade to another protocol */
  return -1;
}


static int
parse_match_net(const struct vec *vec, const union usa *sa, int no_strict)
{
  int n;
  unsigned int a, b, c, d, slash;

  if (sscanf(vec->ptr, "%u.%u.%u.%u/%u%n", &a, &b, &c, &d, &slash, &n)
      != 5) { // NOLINT(cert-err34-c) 'sscanf' used to convert a string to an
            // integer value, but function will not report conversion
            // errors; consider using 'strtol' instead
    slash = 32;
    if (sscanf(vec->ptr, "%u.%u.%u.%u%n", &a, &b, &c, &d, &n)
        != 4) { // NOLINT(cert-err34-c) 'sscanf' used to convert a string to
              // an integer value, but function will not report conversion
              // errors; consider using 'strtol' instead
      n = 0;
    }
  }

  if ((n > 0) && ((size_t)n == vec->len)) {
    if ((a < 256) && (b < 256) && (c < 256) && (d < 256) && (slash < 33)) {
      /* IPv4 format */
      if (sa->sa.sa_family == AF_INET) {
        uint32_t ip = ntohl(sa->sin.sin_addr.s_addr);
        uint32_t net = ((uint32_t)a << 24) | ((uint32_t)b << 16)
                       | ((uint32_t)c << 8) | (uint32_t)d;
        uint32_t mask = slash ? (0xFFFFFFFFu << (32 - slash)) : 0;
        return (ip & mask) == net;
      }
      return 0;
    }
  }
#if defined(USE_IPV6)
  else {
    char ad[50];
    const char *p;

    if (sscanf(vec->ptr, "[%49[^]]]/%u%n", ad, &slash, &n) != 2) {
      slash = 128;
      if (sscanf(vec->ptr, "[%49[^]]]%n", ad, &n) != 1) {
        n = 0;
      }
    }

    if ((n <= 0) && no_strict) {
      /* no square brackets? */
      p = strchr(vec->ptr, '/');
      if (p && (p < (vec->ptr + vec->len))) {
        if (((size_t)(p - vec->ptr) < sizeof(ad))
            && (sscanf(p, "/%u%n", &slash, &n) == 1)) {
          n += (int)(p - vec->ptr);
          mg_strlcpy(ad, vec->ptr, (size_t)(p - vec->ptr) + 1);
        } else {
          n = 0;
        }
      } else if (vec->len < sizeof(ad)) {
        n = (int)vec->len;
        slash = 128;
        mg_strlcpy(ad, vec->ptr, vec->len + 1);
      }
    }

    if ((n > 0) && ((size_t)n == vec->len) && (slash < 129)) {
      p = ad;
      c = 0;
      /* zone indexes are unsupported, at least two colons are needed */
      while (isxdigit((unsigned char)*p) || (*p == '.') || (*p == ':')) {
        if (*(p++) == ':') {
          c++;
        }
      }
      if ((*p == '\0') && (c >= 2)) {
        struct sockaddr_in6 sin6;
        unsigned int i;

        /* for strict validation, an actual IPv6 argument is needed */
        if (sa->sa.sa_family != AF_INET6) {
          return 0;
        }
        if (mg_inet_pton(AF_INET6, ad, &sin6, sizeof(sin6), 0)) {
          /* IPv6 format */
          for (i = 0; i < 16; i++) {
            uint8_t ip = sa->sin6.sin6_addr.s6_addr[i];
            uint8_t net = sin6.sin6_addr.s6_addr[i];
            uint8_t mask = 0;

            if (8 * i + 8 < slash) {
              mask = 0xFFu;
            } else if (8 * i < slash) {
              mask = (uint8_t)(0xFFu << (8 * i + 8 - slash));
            }
            if ((ip & mask) != net) {
              return 0;
            }
          }
          return 1;
        }
      }
    }
  }
#else
  (void)no_strict;
#endif

  /* malformed */
  return -1;
}


static int
set_throttle(const char *spec, const union usa *rsa, const char *uri)
{
  int throttle = 0;
  struct vec vec, val;
  char mult;
  double v;

  while ((spec = next_option(spec, &vec, &val)) != NULL) {
    mult = ',';
    if ((val.ptr == NULL)
        || (sscanf(val.ptr, "%lf%c", &v, &mult)
            < 1) // NOLINT(cert-err34-c) 'sscanf' used to convert a string
                 // to an integer value, but function will not report
                 // conversion errors; consider using 'strtol' instead
        || (v < 0)
        || ((lowercase(&mult) != 'k') && (lowercase(&mult) != 'm')
            && (mult != ','))) {
      continue;
    }
    v *= (lowercase(&mult) == 'k')
             ? 1024
             : ((lowercase(&mult) == 'm') ? 1048576 : 1);
    if (vec.len == 1 && vec.ptr[0] == '*') {
      throttle = (int)v;
    } else {
      int matched = parse_match_net(&vec, rsa, 0);
      if (matched >= 0) {
        /* a valid IP subnet */
        if (matched) {
          throttle = (int)v;
        }
      } else if (match_prefix(vec.ptr, vec.len, uri) > 0) {
        throttle = (int)v;
      }
    }
  }

  return throttle;
}


/* The mg_upload function is superseded by mg_handle_form_request. */
#include "handle_form.inl"


static int
get_first_ssl_listener_index(const struct mg_context *ctx)
{
  unsigned int i;
  int idx = -1;
  if (ctx) {
    for (i = 0; ((idx == -1) && (i < ctx->num_listening_sockets)); i++) {
      idx = ctx->listening_sockets[i].is_ssl ? ((int)(i)) : -1;
    }
  }
  return idx;
}


/* Return host (without port) */
static void
get_host_from_request_info(struct vec *host, const struct mg_request_info *ri)
{
  const char *host_header =
      get_header(ri->http_headers, ri->num_headers, "Host");

  host->ptr = NULL;
  host->len = 0;

  if (host_header != NULL) {
    const char *pos;

    /* If the "Host" is an IPv6 address, like [::1], parse until ]
     * is found. */
    if (*host_header == '[') {
      pos = strchr(host_header, ']');
      if (!pos) {
        /* Malformed hostname starts with '[', but no ']' found */
        DEBUG_TRACE("%s", "Host name format error '[' without ']'");
        return;
      }
      /* terminate after ']' */
      host->ptr = host_header;
      host->len = (size_t)(pos + 1 - host_header);
    } else {
      /* Otherwise, a ':' separates hostname and port number */
      pos = strchr(host_header, ':');
      if (pos != NULL) {
        host->len = (size_t)(pos - host_header);
      } else {
        host->len = strlen(host_header);
      }
      host->ptr = host_header;
    }
  }
}


static int
switch_domain_context(struct mg_connection *conn)
{
  struct vec host;

  get_host_from_request_info(&host, &conn->request_info);

  if (host.ptr) {
    if (conn->ssl) {
      /* This is a HTTPS connection, maybe we have a hostname
       * from SNI (set in ssl_servername_callback). */
      const char *sslhost = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
      if (sslhost && (conn->dom_ctx != &(conn->phys_ctx->dd))) {
        /* We are not using the default domain */
        if ((strlen(sslhost) != host.len)
            || mg_strncasecmp(host.ptr, sslhost, host.len)) {
          /* Mismatch between SNI domain and HTTP domain */
          DEBUG_TRACE("Host mismatch: SNI: %s, HTTPS: %.*s",
                      sslhost,
                      (int)host.len,
                      host.ptr);
          return 0;
        }
      }

    } else {
      struct mg_domain_context *dom = &(conn->phys_ctx->dd);
      while (dom) {
        const char *domName = dom->config[AUTHENTICATION_DOMAIN];
        size_t domNameLen = strlen(domName);
        if ((domNameLen == host.len)
            && !mg_strncasecmp(host.ptr, domName, host.len)) {

          /* Found matching domain */
          DEBUG_TRACE("HTTP domain %s found",
                      dom->config[AUTHENTICATION_DOMAIN]);

          /* TODO: Check if this is a HTTP or HTTPS domain */
          conn->dom_ctx = dom;
          break;
        }
        mg_lock_context(conn->phys_ctx);
        dom = dom->next;
        mg_unlock_context(conn->phys_ctx);
      }
    }

    DEBUG_TRACE("HTTP%s Host: %.*s",
                conn->ssl ? "S" : "",
                (int)host.len,
                host.ptr);

  } else {
    DEBUG_TRACE("HTTP%s Host is not set", conn->ssl ? "S" : "");
    return 1;
  }

  return 1;
}


static void
redirect_to_https_port(struct mg_connection *conn, int port)
{
  char target_url[MG_BUF_LEN];
  int truncated = 0;
  const char *expect_proto =
      (conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET) ? "wss" : "https";

  /* Use "308 Permanent Redirect" */
  int redirect_code = 308;

  /* In any case, close the current connection */
  conn->must_close = 1;

  /* Send host, port, uri and (if it exists) ?query_string */
  if (mg_construct_local_link(
          conn, target_url, sizeof(target_url), expect_proto, port, NULL)
      < 0) {
    truncated = 1;
  } else if (conn->request_info.query_string != NULL) {
    size_t slen1 = strlen(target_url);
    size_t slen2 = strlen(conn->request_info.query_string);
    if ((slen1 + slen2 + 2) < sizeof(target_url)) {
      target_url[slen1] = '?';
      memcpy(target_url + slen1 + 1,
             conn->request_info.query_string,
             slen2);
      target_url[slen1 + slen2 + 1] = 0;
    } else {
      truncated = 1;
    }
  }

  /* Check overflow in location buffer (will not occur if MG_BUF_LEN
   * is used as buffer size) */
  if (truncated) {
    mg_send_http_error(conn, 500, "%s", "Redirect URL too long");
    return;
  }

  /* Use redirect helper function */
  mg_send_http_redirect(conn, target_url, redirect_code);
}


static void
mg_set_handler_type(struct mg_context *phys_ctx,
                    struct mg_domain_context *dom_ctx,
                    const char *uri,
                    int handler_type,
                    int is_delete_request,
                    mg_request_handler handler,
                    struct mg_websocket_subprotocols *subprotocols,
                    mg_websocket_connect_handler connect_handler,
                    mg_websocket_ready_handler ready_handler,
                    mg_websocket_data_handler data_handler,
                    mg_websocket_close_handler close_handler,
                    mg_authorization_handler auth_handler,
                    void *cbdata)
{
  struct mg_handler_info *tmp_rh, **lastref;
  size_t urilen = strlen(uri);

  if (handler_type == WEBSOCKET_HANDLER) {
    DEBUG_ASSERT(handler == NULL);
    DEBUG_ASSERT(is_delete_request || connect_handler != NULL
                 || ready_handler != NULL || data_handler != NULL
                 || close_handler != NULL);

    DEBUG_ASSERT(auth_handler == NULL);
    if (handler != NULL) {
      return;
    }
    if (!is_delete_request && (connect_handler == NULL)
        && (ready_handler == NULL) && (data_handler == NULL)
        && (close_handler == NULL)) {
      return;
    }
    if (auth_handler != NULL) {
      return;
    }

  } else if (handler_type == REQUEST_HANDLER) {
    DEBUG_ASSERT(connect_handler == NULL && ready_handler == NULL
                 && data_handler == NULL && close_handler == NULL);
    DEBUG_ASSERT(is_delete_request || (handler != NULL));
    DEBUG_ASSERT(auth_handler == NULL);

    if ((connect_handler != NULL) || (ready_handler != NULL)
        || (data_handler != NULL) || (close_handler != NULL)) {
      return;
    }
    if (!is_delete_request && (handler == NULL)) {
      return;
    }
    if (auth_handler != NULL) {
      return;
    }

  } else if (handler_type == AUTH_HANDLER) {
    DEBUG_ASSERT(handler == NULL);
    DEBUG_ASSERT(connect_handler == NULL && ready_handler == NULL
                 && data_handler == NULL && close_handler == NULL);
    DEBUG_ASSERT(is_delete_request || (auth_handler != NULL));
    if (handler != NULL) {
      return;
    }
    if ((connect_handler != NULL) || (ready_handler != NULL)
        || (data_handler != NULL) || (close_handler != NULL)) {
      return;
    }
    if (!is_delete_request && (auth_handler == NULL)) {
      return;
    }
  } else {
    /* Unknown handler type. */
    return;
  }

  if (!phys_ctx || !dom_ctx) {
    /* no context available */
    return;
  }

  mg_lock_context(phys_ctx);

  /* first try to find an existing handler */
  do {
    lastref = &(dom_ctx->handlers);
    for (tmp_rh = dom_ctx->handlers; tmp_rh != NULL;
         tmp_rh = tmp_rh->next) {
      if (tmp_rh->handler_type == handler_type
          && (urilen == tmp_rh->uri_len) && !strcmp(tmp_rh->uri, uri)) {
        if (!is_delete_request) {
          /* update existing handler */
          if (handler_type == REQUEST_HANDLER) {
            /* Wait for end of use before updating */
            if (tmp_rh->refcount) {
              mg_unlock_context(phys_ctx);
              mg_sleep(1);
              mg_lock_context(phys_ctx);
              /* tmp_rh might have been freed, search again. */
              break;
            }
            /* Ok, the handler is no more use -> Update it */
            tmp_rh->handler = handler;
          } else if (handler_type == WEBSOCKET_HANDLER) {
            tmp_rh->subprotocols = subprotocols;
            tmp_rh->connect_handler = connect_handler;
            tmp_rh->ready_handler = ready_handler;
            tmp_rh->data_handler = data_handler;
            tmp_rh->close_handler = close_handler;
          } else { /* AUTH_HANDLER */
            tmp_rh->auth_handler = auth_handler;
          }
          tmp_rh->cbdata = cbdata;
        } else {
          /* remove existing handler */
          if (handler_type == REQUEST_HANDLER) {
            /* Wait for end of use before removing */
            if (tmp_rh->refcount) {
              tmp_rh->removing = 1;
              mg_unlock_context(phys_ctx);
              mg_sleep(1);
              mg_lock_context(phys_ctx);
              /* tmp_rh might have been freed, search again. */
              break;
            }
            /* Ok, the handler is no more used */
          }
          *lastref = tmp_rh->next;
          mg_free(tmp_rh->uri);
          mg_free(tmp_rh);
        }
        mg_unlock_context(phys_ctx);
        return;
      }
      lastref = &(tmp_rh->next);
    }
  } while (tmp_rh != NULL);

  if (is_delete_request) {
    /* no handler to set, this was a remove request to a non-existing
     * handler */
    mg_unlock_context(phys_ctx);
    return;
  }

  tmp_rh =
      (struct mg_handler_info *)mg_calloc_ctx(1,
                                              sizeof(struct mg_handler_info),
                                              phys_ctx);
  if (tmp_rh == NULL) {
    mg_unlock_context(phys_ctx);
    mg_cry_ctx_internal(phys_ctx,
                        "%s",
                        "Cannot create new request handler struct, OOM");
    return;
  }
  tmp_rh->uri = mg_strdup_ctx(uri, phys_ctx);
  if (!tmp_rh->uri) {
    mg_unlock_context(phys_ctx);
    mg_free(tmp_rh);
    mg_cry_ctx_internal(phys_ctx,
                        "%s",
                        "Cannot create new request handler struct, OOM");
    return;
  }
  tmp_rh->uri_len = urilen;
  if (handler_type == REQUEST_HANDLER) {
    tmp_rh->refcount = 0;
    tmp_rh->removing = 0;
    tmp_rh->handler = handler;
  } else if (handler_type == WEBSOCKET_HANDLER) {
    tmp_rh->subprotocols = subprotocols;
    tmp_rh->connect_handler = connect_handler;
    tmp_rh->ready_handler = ready_handler;
    tmp_rh->data_handler = data_handler;
    tmp_rh->close_handler = close_handler;
  } else { /* AUTH_HANDLER */
    tmp_rh->auth_handler = auth_handler;
  }
  tmp_rh->cbdata = cbdata;
  tmp_rh->handler_type = handler_type;
  tmp_rh->next = NULL;

  *lastref = tmp_rh;
  mg_unlock_context(phys_ctx);
}


CIVETWEB_API void
mg_set_request_handler(struct mg_context *ctx,
                       const char *uri,
                       mg_request_handler handler,
                       void *cbdata)
{
  mg_set_handler_type(ctx,
                      &(ctx->dd),
                      uri,
                      REQUEST_HANDLER,
                      handler == NULL,
                      handler,
                      NULL,
                      NULL,
                      NULL,
                      NULL,
                      NULL,
                      NULL,
                      cbdata);
}


CIVETWEB_API void
mg_set_websocket_handler(struct mg_context *ctx,
                         const char *uri,
                         mg_websocket_connect_handler connect_handler,
                         mg_websocket_ready_handler ready_handler,
                         mg_websocket_data_handler data_handler,
                         mg_websocket_close_handler close_handler,
                         void *cbdata)
{
  mg_set_websocket_handler_with_subprotocols(ctx,
                                             uri,
                                             NULL,
                                             connect_handler,
                                             ready_handler,
                                             data_handler,
                                             close_handler,
                                             cbdata);
}


CIVETWEB_API void
mg_set_websocket_handler_with_subprotocols(
    struct mg_context *ctx,
    const char *uri,
    struct mg_websocket_subprotocols *subprotocols,
    mg_websocket_connect_handler connect_handler,
    mg_websocket_ready_handler ready_handler,
    mg_websocket_data_handler data_handler,
    mg_websocket_close_handler close_handler,
    void *cbdata)
{
  int is_delete_request = (connect_handler == NULL) && (ready_handler == NULL)
                          && (data_handler == NULL)
                          && (close_handler == NULL);
  mg_set_handler_type(ctx,
                      &(ctx->dd),
                      uri,
                      WEBSOCKET_HANDLER,
                      is_delete_request,
                      NULL,
                      subprotocols,
                      connect_handler,
                      ready_handler,
                      data_handler,
                      close_handler,
                      NULL,
                      cbdata);
}


CIVETWEB_API void
mg_set_auth_handler(struct mg_context *ctx,
                    const char *uri,
                    mg_authorization_handler handler,
                    void *cbdata)
{
  mg_set_handler_type(ctx,
                      &(ctx->dd),
                      uri,
                      AUTH_HANDLER,
                      handler == NULL,
                      NULL,
                      NULL,
                      NULL,
                      NULL,
                      NULL,
                      NULL,
                      handler,
                      cbdata);
}


static int
get_request_handler(struct mg_connection *conn,
                    int handler_type,
                    mg_request_handler *handler,
                    struct mg_websocket_subprotocols **subprotocols,
                    mg_websocket_connect_handler *connect_handler,
                    mg_websocket_ready_handler *ready_handler,
                    mg_websocket_data_handler *data_handler,
                    mg_websocket_close_handler *close_handler,
                    mg_authorization_handler *auth_handler,
                    void **cbdata,
                    struct mg_handler_info **handler_info)
{
  const struct mg_request_info *request_info = mg_get_request_info(conn);
  if (request_info) {
    const char *uri = request_info->local_uri;
    size_t urilen = strlen(uri);
    struct mg_handler_info *tmp_rh;
    int step, matched;

    if (!conn || !conn->phys_ctx || !conn->dom_ctx) {
      return 0;
    }

    mg_lock_context(conn->phys_ctx);

    for (step = 0; step < 3; step++) {
      for (tmp_rh = conn->dom_ctx->handlers; tmp_rh != NULL;
           tmp_rh = tmp_rh->next) {
        if (tmp_rh->handler_type != handler_type) {
          continue;
        }
        if (step == 0) {
          /* first try for an exact match */
          matched = (tmp_rh->uri_len == urilen)
                    && (strcmp(tmp_rh->uri, uri) == 0);
        } else if (step == 1) {
          /* next try for a partial match, we will accept
          uri/something */
          matched =
              (tmp_rh->uri_len < urilen)
              && (uri[tmp_rh->uri_len] == '/')
              && (memcmp(tmp_rh->uri, uri, tmp_rh->uri_len) == 0);
        } else {
          /* finally try for pattern match */
          matched =
              match_prefix(tmp_rh->uri, tmp_rh->uri_len, uri) > 0;
        }
        if (matched) {
          if (handler_type == WEBSOCKET_HANDLER) {
            *subprotocols = tmp_rh->subprotocols;
            *connect_handler = tmp_rh->connect_handler;
            *ready_handler = tmp_rh->ready_handler;
            *data_handler = tmp_rh->data_handler;
            *close_handler = tmp_rh->close_handler;
          } else if (handler_type == REQUEST_HANDLER) {
            if (tmp_rh->removing) {
              /* Treat as none found */
              step = 2;
              break;
            }
            *handler = tmp_rh->handler;
            /* Acquire handler and give it back */
            tmp_rh->refcount++;
            *handler_info = tmp_rh;
          } else { /* AUTH_HANDLER */
            *auth_handler = tmp_rh->auth_handler;
          }
          *cbdata = tmp_rh->cbdata;
          mg_unlock_context(conn->phys_ctx);
          return 1;
        }
      }
    }

    mg_unlock_context(conn->phys_ctx);
  }
  return 0; /* none found */
}


/* Check if the script file is in a path, allowed for script files.
 * This can be used if uploading files is possible not only for the server
 * admin, and the upload mechanism does not check the file extension.
 */
static int
is_in_script_path(const struct mg_connection *conn, const char *path)
{
  /* TODO (Feature): Add config value for allowed script path.
   * Default: All allowed. */
  (void)conn;
  (void)path;
  return 1;
}


#if defined(USE_WEBSOCKET) && defined(MG_EXPERIMENTAL_INTERFACES)
static int
experimental_websocket_client_data_wrapper(struct mg_connection *conn,
                                           int bits,
                                           char *data,
                                           size_t len,
                                           void *cbdata)
{
  struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
  if (pcallbacks->websocket_data) {
    return pcallbacks->websocket_data(conn, bits, data, len);
  }
  /* No handler set - assume "OK" */
  return 1;
}


static void
experimental_websocket_client_close_wrapper(const struct mg_connection *conn,
                                            void *cbdata)
{
  struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
  if (pcallbacks->connection_close) {
    pcallbacks->connection_close(conn);
  }
}
#endif


/* Decrement recount of handler. conn must not be NULL, handler_info may be NULL
 */
static void
release_handler_ref(struct mg_connection *conn,
                    struct mg_handler_info *handler_info)
{
  if (handler_info != NULL) {
    /* Use context lock for ref counter */
    mg_lock_context(conn->phys_ctx);
    handler_info->refcount--;
    mg_unlock_context(conn->phys_ctx);
  }
}


/* This is the heart of the Civetweb's logic.
 * This function is called when the request is read, parsed and validated,
 * and Civetweb must decide what action to take: serve a file, or
 * a directory, or call embedded function, etcetera. */
static void
handle_request(struct mg_connection *conn)
{
  struct mg_request_info *ri = &conn->request_info;
  char path[UTF8_PATH_MAX];
  int uri_len, ssl_index;
  int is_found = 0, is_script_resource = 0, is_websocket_request = 0,
      is_put_or_delete_request = 0, is_callback_resource = 0,
      is_template_text_file = 0, is_webdav_request = 0;
  int i;
  struct mg_file file = STRUCT_FILE_INITIALIZER;
  mg_request_handler callback_handler = NULL;
  struct mg_handler_info *handler_info = NULL;
  struct mg_websocket_subprotocols *subprotocols;
  mg_websocket_connect_handler ws_connect_handler = NULL;
  mg_websocket_ready_handler ws_ready_handler = NULL;
  mg_websocket_data_handler ws_data_handler = NULL;
  mg_websocket_close_handler ws_close_handler = NULL;
  void *callback_data = NULL;
  mg_authorization_handler auth_handler = NULL;
  void *auth_callback_data = NULL;
  int handler_type;
  time_t curtime = time(NULL);
  char date[64];
  char *tmp;

  path[0] = 0;

  /* 0. Reset internal state (required for HTTP/2 proxy) */
  conn->request_state = 0;

  /* 1. get the request url */
  /* 1.1. split into url and query string */
  if ((conn->request_info.query_string = strchr(ri->request_uri, '?'))
      != NULL) {
    *((char *)conn->request_info.query_string++) = '\0';
  }

  /* 1.2. do a https redirect, if required. Do not decode URIs yet. */
  if (!conn->client.is_ssl && conn->client.ssl_redir) {
    ssl_index = get_first_ssl_listener_index(conn->phys_ctx);
    if (ssl_index >= 0) {
      int port = (int)ntohs(USA_IN_PORT_UNSAFE(
          &(conn->phys_ctx->listening_sockets[ssl_index].lsa)));
      redirect_to_https_port(conn, port);
    } else {
      /* A http to https forward port has been specified,
       * but no https port to forward to. */
      mg_send_http_error(conn,
                         503,
                         "%s",
                         "Error: SSL forward not configured properly");
      mg_cry_internal(conn,
                      "%s",
                      "Can not redirect to SSL, no SSL port available");
    }
    return;
  }
  uri_len = (int)strlen(ri->local_uri);

  /* 1.3. decode url (if config says so) */
  if (should_decode_url(conn)) {
    url_decode_in_place((char *)ri->local_uri);
  }

  /* URL decode the query-string only if explicitly set in the configuration
   */
  if (conn->request_info.query_string) {
    if (should_decode_query_string(conn)) {
      url_decode_in_place((char *)conn->request_info.query_string);
    }
  }

  /* 1.4. clean URIs, so a path like allowed_dir/../forbidden_file is not
   * possible. The fact that we cleaned the URI is stored in that the
   * pointer to ri->local_ur and ri->local_uri_raw are now different.
   * ri->local_uri_raw still points to memory allocated in
   * worker_thread_run(). ri->local_uri is private to the request so we
   * don't have to use preallocated memory here. */
  tmp = mg_strdup(ri->local_uri_raw);
  if (!tmp) {
    /* Out of memory. We cannot do anything reasonable here. */
    return;
  }
  remove_dot_segments(tmp);
  ri->local_uri = tmp;

  /* step 1. completed, the url is known now */
  DEBUG_TRACE("REQUEST: %s %s", ri->request_method, ri->local_uri);

  /* 2. if this ip has limited speed, set it for this connection */
  conn->throttle = set_throttle(conn->dom_ctx->config[THROTTLE],
                                &conn->client.rsa,
                                ri->local_uri);

  /* 3. call a "handle everything" callback, if registered */
  if (conn->phys_ctx->callbacks.begin_request != NULL) {
    /* Note that since V1.7 the "begin_request" function is called
     * before an authorization check. If an authorization check is
     * required, use a request_handler instead. */
    i = conn->phys_ctx->callbacks.begin_request(conn);
    if (i > 0) {
      /* callback already processed the request. Store the
      return value as a status code for the access log. */
      conn->status_code = i;
      if (!conn->must_close) {
        discard_unread_request_data(conn);
      }
      DEBUG_TRACE("%s", "begin_request handled request");
      return;
    } else if (i == 0) {
      /* civetweb should process the request */
    } else {
      /* unspecified - may change with the next version */
      DEBUG_TRACE("%s", "done (undocumented behavior)");
      return;
    }
  }

  /* request not yet handled by a handler or redirect, so the request
   * is processed here */

  /* 4. Check for CORS preflight requests and handle them (if configured).
   * https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS
   */
  if (!strcmp(ri->request_method, "OPTIONS")) {
    /* Send a response to CORS preflights only if
     * access_control_allow_methods is not NULL and not an empty string.
     * In this case, scripts can still handle CORS. */
    const char *cors_meth_cfg =
        conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_METHODS];
    const char *cors_orig_cfg =
        conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_ORIGIN];
    const char *cors_origin =
        get_header(ri->http_headers, ri->num_headers, "Origin");
    const char *cors_acrm = get_header(ri->http_headers,
                                       ri->num_headers,
                                       "Access-Control-Request-Method");

    /* Todo: check if cors_origin is in cors_orig_cfg.
     * Or, let the client check this. */

    if ((cors_meth_cfg != NULL) && (*cors_meth_cfg != 0)
        && (cors_orig_cfg != NULL) && (*cors_orig_cfg != 0)
        && (cors_origin != NULL) && (cors_acrm != NULL)) {
      /* This is a valid CORS preflight, and the server is configured
       * to handle it automatically. */
      const char *cors_acrh =
          get_header(ri->http_headers,
                     ri->num_headers,
                     "Access-Control-Request-Headers");

      gmt_time_string(date, sizeof(date), &curtime);
      mg_printf(conn,
                "HTTP/1.1 200 OK\r\n"
                "Date: %s\r\n"
                "Access-Control-Allow-Origin: %s\r\n"
                "Access-Control-Allow-Methods: %s\r\n"
                "Content-Length: 0\r\n"
                "Connection: %s\r\n",
                date,
                cors_orig_cfg,
                ((cors_meth_cfg[0] == '*') ? cors_acrm : cors_meth_cfg),
                suggest_connection_header(conn));

      if (cors_acrh != NULL) {
        /* CORS request is asking for additional headers */
        const char *cors_hdr_cfg =
            conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_HEADERS];

        if ((cors_hdr_cfg != NULL) && (*cors_hdr_cfg != 0)) {
          /* Allow only if access_control_allow_headers is
           * not NULL and not an empty string. If this
           * configuration is set to *, allow everything.
           * Otherwise this configuration must be a list
           * of allowed HTTP header names. */
          mg_printf(conn,
                    "Access-Control-Allow-Headers: %s\r\n",
                    ((cors_hdr_cfg[0] == '*') ? cors_acrh
                                              : cors_hdr_cfg));
        }
      }
      mg_printf(conn, "Access-Control-Max-Age: 60\r\n");
      mg_printf(conn, "\r\n");
      DEBUG_TRACE("%s", "OPTIONS done");
      return;
    }
  }

  /* 5. interpret the url to find out how the request must be handled
   */
  /* 5.1. first test, if the request targets the regular http(s)://
   * protocol namespace or the websocket ws(s):// protocol namespace.
   */
  is_websocket_request = (conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET);
#if defined(USE_WEBSOCKET)
  handler_type = is_websocket_request ? WEBSOCKET_HANDLER : REQUEST_HANDLER;
#else
  handler_type = REQUEST_HANDLER;
#endif /* defined(USE_WEBSOCKET) */

  if (is_websocket_request) {
    HTTP1_only;
  }

  /* 5.2. check if the request will be handled by a callback */
  if (get_request_handler(conn,
                          handler_type,
                          &callback_handler,
                          &subprotocols,
                          &ws_connect_handler,
                          &ws_ready_handler,
                          &ws_data_handler,
                          &ws_close_handler,
                          NULL,
                          &callback_data,
                          &handler_info)) {
    /* 5.2.1. A callback will handle this request. All requests
     * handled by a callback have to be considered as requests
     * to a script resource. */
    is_callback_resource = 1;
    is_script_resource = 1;
    is_put_or_delete_request = is_put_or_delete_method(conn);
    /* Never handle a C callback according to File WebDav rules,
     * even if it is a webdav method */
    is_webdav_request = 0; /* is_civetweb_webdav_method(conn); */
  } else {
  no_callback_resource:

    /* 5.2.2. No callback is responsible for this request. The URI
     * addresses a file based resource (static content or Lua/cgi
     * scripts in the file system). */
    is_callback_resource = 0;
    interpret_uri(conn,
                  path,
                  sizeof(path),
                  &file.stat,
                  &is_found,
                  &is_script_resource,
                  &is_websocket_request,
                  &is_put_or_delete_request,
                  &is_webdav_request,
                  &is_template_text_file);
  }

  /* 5.3. A webdav request (PROPFIND/PROPPATCH/LOCK/UNLOCK) */
  if (is_webdav_request) {
    /* TODO: Do we need a config option? */
    const char *webdav_enable = conn->dom_ctx->config[ENABLE_WEBDAV];
    if (webdav_enable[0] != 'y') {
      mg_send_http_error(conn,
                         405,
                         "%s method not allowed",
                         conn->request_info.request_method);
      DEBUG_TRACE("%s", "webdav rejected");
      return;
    }
  }

  /* 6. authorization check */
  /* 6.1. a custom authorization handler is installed */
  if (get_request_handler(conn,
                          AUTH_HANDLER,
                          NULL,
                          NULL,
                          NULL,
                          NULL,
                          NULL,
                          NULL,
                          &auth_handler,
                          &auth_callback_data,
                          NULL)) {
    if (!auth_handler(conn, auth_callback_data)) {

      /* Callback handler will not be used anymore. Release it */
      release_handler_ref(conn, handler_info);
      DEBUG_TRACE("%s", "auth handler rejected request");
      return;
    }
  } else if (is_put_or_delete_request && !is_script_resource
             && !is_callback_resource) {
    HTTP1_only;
    /* 6.2. this request is a PUT/DELETE to a real file */
    /* 6.2.1. thus, the server must have real files */
#if defined(NO_FILES)
    if (1) {
#else
    if (conn->dom_ctx->config[DOCUMENT_ROOT] == NULL
        || conn->dom_ctx->config[PUT_DELETE_PASSWORDS_FILE] == NULL) {
#endif
      /* This code path will not be called for request handlers */
      DEBUG_ASSERT(handler_info == NULL);

      /* This server does not have any real files, thus the
       * PUT/DELETE methods are not valid. */
      mg_send_http_error(conn,
                         405,
                         "%s method not allowed",
                         conn->request_info.request_method);
      DEBUG_TRACE("%s", "all file based put/delete requests rejected");
      return;
    }

#if !defined(NO_FILES)
    /* 6.2.2. Check if put authorization for static files is
     * available.
     */
    if (!is_authorized_for_put(conn)) {
      send_authorization_request(conn, NULL);
      DEBUG_TRACE("%s", "file write needs authorization");
      return;
    }
#endif

  } else {
    /* 6.3. This is either a OPTIONS, GET, HEAD or POST request,
     * or it is a PUT or DELETE request to a resource that does not
     * correspond to a file. Check authorization. */
    if (!check_authorization(conn, path)) {
      send_authorization_request(conn, NULL);

      /* Callback handler will not be used anymore. Release it */
      release_handler_ref(conn, handler_info);
      DEBUG_TRACE("%s", "access authorization required");
      return;
    }
  }

  /* request is authorized or does not need authorization */

  /* 7. check if there are request handlers for this uri */
  if (is_callback_resource) {
    HTTP1_only;
    if (!is_websocket_request) {
      i = callback_handler(conn, callback_data);

      /* Callback handler will not be used anymore. Release it */
      release_handler_ref(conn, handler_info);

      if (i > 0) {
        /* Do nothing, callback has served the request. Store
         * then return value as status code for the log and discard
         * all data from the client not used by the callback. */
        conn->status_code = i;
        if (!conn->must_close) {
          discard_unread_request_data(conn);
        }
      } else {
        /* The handler did NOT handle the request. */
        /* Some proper reactions would be:
         * a) close the connections without sending anything
         * b) send a 404 not found
         * c) try if there is a file matching the URI
         * It would be possible to do a, b or c in the callback
         * implementation, and return 1 - we cannot do anything
         * here, that is not possible in the callback.
         *
         * TODO: What would be the best reaction here?
         * (Note: The reaction may change, if there is a better
         * idea.)
         */

        /* For the moment, use option c: We look for a proper file,
         * but since a file request is not always a script resource,
         * the authorization check might be different. */
        callback_handler = NULL;

        /* Here we are at a dead end:
         * According to URI matching, a callback should be
         * responsible for handling the request,
         * we called it, but the callback declared itself
         * not responsible.
         * We use a goto here, to get out of this dead end,
         * and continue with the default handling.
         * A goto here is simpler and better to understand
         * than some curious loop. */
        goto no_callback_resource;
      }
    } else {
#if defined(USE_WEBSOCKET)
      handle_websocket_request(conn,
                               path,
                               is_callback_resource,
                               subprotocols,
                               ws_connect_handler,
                               ws_ready_handler,
                               ws_data_handler,
                               ws_close_handler,
                               callback_data);
#endif
    }
    DEBUG_TRACE("%s", "websocket handling done");
    return;
  }

  /* 8. handle websocket requests */
#if defined(USE_WEBSOCKET)
  if (is_websocket_request) {
    HTTP1_only;
    if (is_script_resource) {

      if (is_in_script_path(conn, path)) {
        /* Websocket Lua script */
        handle_websocket_request(conn,
                                 path,
                                 0 /* Lua Script */,
                                 NULL,
                                 NULL,
                                 NULL,
                                 NULL,
                                 NULL,
                                 conn->phys_ctx->user_data);
      } else {
        /* Script was in an illegal path */
        mg_send_http_error(conn, 403, "%s", "Forbidden");
      }
    } else {
      mg_send_http_error(conn, 404, "%s", "Not found");
    }
    DEBUG_TRACE("%s", "websocket script done");
    return;
  } else
#endif

#if defined(NO_FILES)
    /* 9a. In case the server uses only callbacks, this uri is
     * unknown.
     * Then, all request handling ends here. */
    mg_send_http_error(conn, 404, "%s", "Not Found");

#else
  /* 9b. This request is either for a static file or resource handled
   * by a script file. Thus, a DOCUMENT_ROOT must exist. */
  if (conn->dom_ctx->config[DOCUMENT_ROOT] == NULL) {
    mg_send_http_error(conn, 404, "%s", "Not Found");
    DEBUG_TRACE("%s", "no document root available");
    return;
  }

  /* 10. Request is handled by a script */
  if (is_script_resource) {
    HTTP1_only;
    handle_file_based_request(conn, path, &file);
    DEBUG_TRACE("%s", "script handling done");
    return;
  }

  /* Request was not handled by a callback or script. It will be
   * handled by a server internal method. */

  /* 11. Handle put/delete/mkcol requests */
  if (is_put_or_delete_request) {
    HTTP1_only;
    /* 11.1. PUT method */
    if (!strcmp(ri->request_method, "PUT")) {
      put_file(conn, path);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.2. DELETE method */
    if (!strcmp(ri->request_method, "DELETE")) {
      delete_file(conn, path);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.3. MKCOL method */
    if (!strcmp(ri->request_method, "MKCOL")) {
      dav_mkcol(conn, path);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.4. MOVE method */
    if (!strcmp(ri->request_method, "MOVE")) {
      dav_move_file(conn, path, 0);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    if (!strcmp(ri->request_method, "COPY")) {
      dav_move_file(conn, path, 1);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.5. LOCK method */
    if (!strcmp(ri->request_method, "LOCK")) {
      dav_lock_file(conn, path);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.6. UNLOCK method */
    if (!strcmp(ri->request_method, "UNLOCK")) {
      dav_unlock_file(conn, path);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.7. PROPPATCH method */
    if (!strcmp(ri->request_method, "PROPPATCH")) {
      dav_proppatch(conn, path);
      DEBUG_TRACE("handling %s request to %s done",
                  ri->request_method,
                  path);
      return;
    }
    /* 11.8. Other methods, e.g.: PATCH
     * This method is not supported for static resources,
     * only for scripts (Lua, CGI) and callbacks. */
    mg_send_http_error(conn,
                       405,
                       "%s method not allowed",
                       conn->request_info.request_method);
    DEBUG_TRACE("method %s on %s is not supported",
                ri->request_method,
                path);
    return;
  }

  /* 11. File does not exist, or it was configured that it should be
   * hidden */
  if (!is_found || (must_hide_file(conn, path))) {
    mg_send_http_error(conn, 404, "%s", "Not found");
    DEBUG_TRACE("handling %s request to %s: file not found",
                ri->request_method,
                path);
    return;
  }

  /* 12. Directory uris should end with a slash */
  if (file.stat.is_directory && ((uri_len = (int)strlen(ri->local_uri)) > 0)
      && (ri->local_uri[uri_len - 1] != '/')) {

    /* Path + server root */
    size_t buflen = UTF8_PATH_MAX * 2 + 2;
    char *new_path;

    if (ri->query_string) {
      buflen += strlen(ri->query_string);
    }
    new_path = (char *)mg_malloc_ctx(buflen, conn->phys_ctx);
    if (!new_path) {
      mg_send_http_error(conn, 500, "out or memory");
    } else {
      mg_get_request_link(conn, new_path, buflen - 1);
      strcat(new_path, "/");
      if (ri->query_string) {
        /* Append ? and query string */
        strcat(new_path, "?");
        strcat(new_path, ri->query_string);
      }
      mg_send_http_redirect(conn, new_path, 301);
      mg_free(new_path);
    }
    DEBUG_TRACE("%s request to %s: directory redirection sent",
                ri->request_method,
                path);
    return;
  }

  /* 13. Handle other methods than GET/HEAD */
  /* 13.1. Handle PROPFIND */
  if (!strcmp(ri->request_method, "PROPFIND")) {
    handle_propfind(conn, path, &file.stat);
    DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
    return;
  }
  /* 13.2. Handle OPTIONS for files */
  if (!strcmp(ri->request_method, "OPTIONS")) {
    /* This standard handler is only used for real files.
     * Scripts should support the OPTIONS method themselves, to allow a
     * maximum flexibility.
     * Lua and CGI scripts may fully support CORS this way (including
     * preflights). */
    send_options(conn);
    DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
    return;
  }
  /* 13.3. everything but GET and HEAD (e.g. POST) */
  if ((0 != strcmp(ri->request_method, "GET"))
      && (0 != strcmp(ri->request_method, "HEAD"))) {
    mg_send_http_error(conn,
                       405,
                       "%s method not allowed",
                       conn->request_info.request_method);
    DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
    return;
  }

  /* 14. directories */
  if (file.stat.is_directory) {
    /* Substitute files have already been handled above. */
    /* Here we can either generate and send a directory listing,
     * or send an "access denied" error. */
    if (!mg_strcasecmp(conn->dom_ctx->config[ENABLE_DIRECTORY_LISTING],
                       "yes")) {
      handle_directory_request(conn, path);
    } else {
      mg_send_http_error(conn,
                         403,
                         "%s",
                         "Error: Directory listing denied");
    }
    DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
    return;
  }

  /* 15. Files with search/replace patterns: LSP and SSI */
  if (is_template_text_file) {
    HTTP1_only;
    handle_file_based_request(conn, path, &file);
    DEBUG_TRACE("handling %s request to %s done (template)",
                ri->request_method,
                path);
    return;
  }

  /* 16. Static file - maybe cached */
#if !defined(NO_CACHING)
  if ((!conn->in_error_handler) && is_not_modified(conn, &file.stat)) {
    /* Send 304 "Not Modified" - this must not send any body data */
    handle_not_modified_static_file_request(conn, &file);
    DEBUG_TRACE("handling %s request to %s done (not modified)",
                ri->request_method,
                path);
    return;
  }
#endif /* !NO_CACHING */

  /* 17. Static file - not cached */
  handle_static_file_request(conn, path, &file, NULL, NULL);
  DEBUG_TRACE("handling %s request to %s done (static)",
              ri->request_method,
              path);

#endif /* !defined(NO_FILES) */
}


#if !defined(NO_FILESYSTEMS)
static void
handle_file_based_request(struct mg_connection *conn,
                          const char *path,
                          struct mg_file *file)
{
#if !defined(NO_CGI)
  unsigned char cgi_config_idx, inc, max;
#endif

  if (!conn || !conn->dom_ctx) {
    return;
  }

#if defined(USE_LUA)
  if (match_prefix_strlen(conn->dom_ctx->config[LUA_SERVER_PAGE_EXTENSIONS],
                          path)
      > 0) {
    if (is_in_script_path(conn, path)) {
      /* Lua server page: an SSI like page containing mostly plain
       * html code plus some tags with server generated contents. */
      handle_lsp_request(conn, path, file, NULL);
    } else {
      /* Script was in an illegal path */
      mg_send_http_error(conn, 403, "%s", "Forbidden");
    }
    return;
  }

  if (match_prefix_strlen(conn->dom_ctx->config[LUA_SCRIPT_EXTENSIONS], path)
      > 0) {
    if (is_in_script_path(conn, path)) {
      /* Lua in-server module script: a CGI like script used to
       * generate the entire reply. */
      mg_exec_lua_script(conn, path, NULL);
    } else {
      /* Script was in an illegal path */
      mg_send_http_error(conn, 403, "%s", "Forbidden");
    }
    return;
  }
#endif

#if defined(USE_DUKTAPE)
  if (match_prefix_strlen(conn->dom_ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
                          path)
      > 0) {
    if (is_in_script_path(conn, path)) {
      /* Call duktape to generate the page */
      mg_exec_duktape_script(conn, path);
    } else {
      /* Script was in an illegal path */
      mg_send_http_error(conn, 403, "%s", "Forbidden");
    }
    return;
  }
#endif

#if !defined(NO_CGI)
  inc = CGI2_EXTENSIONS - CGI_EXTENSIONS;
  max = PUT_DELETE_PASSWORDS_FILE - CGI_EXTENSIONS;
  for (cgi_config_idx = 0; cgi_config_idx < max; cgi_config_idx += inc) {
    if (conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx] != NULL) {
      if (match_prefix_strlen(
              conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx],
              path)
          > 0) {
        if (is_in_script_path(conn, path)) {
          /* CGI scripts may support all HTTP methods */
          handle_cgi_request(conn, path, cgi_config_idx);
        } else {
          /* Script was in an illegal path */
          mg_send_http_error(conn, 403, "%s", "Forbidden");
        }
        return;
      }
    }
  }
#endif /* !NO_CGI */

  if (match_prefix_strlen(conn->dom_ctx->config[SSI_EXTENSIONS], path) > 0) {
    if (is_in_script_path(conn, path)) {
      handle_ssi_file_request(conn, path, file);
    } else {
      /* Script was in an illegal path */
      mg_send_http_error(conn, 403, "%s", "Forbidden");
    }
    return;
  }

#if !defined(NO_CACHING)
  if ((!conn->in_error_handler) && is_not_modified(conn, &file->stat)) {
    /* Send 304 "Not Modified" - this must not send any body data */
    handle_not_modified_static_file_request(conn, file);
    return;
  }
#endif /* !NO_CACHING */

  handle_static_file_request(conn, path, file, NULL, NULL);
}
#endif /* NO_FILESYSTEMS */


static void
close_all_listening_sockets(struct mg_context *ctx)
{
  unsigned int i;
  if (!ctx) {
    return;
  }

  for (i = 0; i < ctx->num_listening_sockets; i++) {
    closesocket(ctx->listening_sockets[i].sock);
#if defined(USE_X_DOM_SOCKET)
    /* For unix domain sockets, the socket name represents a file that has
     * to be deleted. */
    /* See
     * https://stackoverflow.com/questions/15716302/so-reuseaddr-and-af-unix
     */
    if ((ctx->listening_sockets[i].lsa.sin.sin_family == AF_UNIX)
        && (ctx->listening_sockets[i].sock != INVALID_SOCKET)) {
      IGNORE_UNUSED_RESULT(
          remove(ctx->listening_sockets[i].lsa.sun.sun_path));
    }
#endif
    ctx->listening_sockets[i].sock = INVALID_SOCKET;
  }
  mg_free(ctx->listening_sockets);
  ctx->listening_sockets = NULL;
  mg_free(ctx->listening_socket_fds);
  ctx->listening_socket_fds = NULL;
}


/* Valid listening port specification is: [ip_address:]port[s]
 * Examples for IPv4: 80, 443s, 127.0.0.1:3128, 192.0.2.3:8080s
 * Examples for IPv6: [::]:80, [::1]:80,
 *   [2001:0db8:7654:3210:FEDC:BA98:7654:3210]:443s
 *   see https://tools.ietf.org/html/rfc3513#section-2.2
 * In order to bind to both, IPv4 and IPv6, you can either add
 * both ports using 8080,[::]:8080, or the short form +8080.
 * Both forms differ in detail: 8080,[::]:8080 create two sockets,
 * one only accepting IPv4 the other only IPv6. +8080 creates
 * one socket accepting IPv4 and IPv6. Depending on the IPv6
 * environment, they might work differently, or might not work
 * at all - it must be tested what options work best in the
 * relevant network environment.
 */
static int
parse_port_string(const struct vec *vec, struct socket *so, int *ip_version)
{
  unsigned int a, b, c, d;
  unsigned port;
  unsigned long portUL;
  int ch, len;
  const char *cb;
  char *endptr;
#if defined(USE_IPV6)
  char buf[100] = {0};
#endif

  /* MacOS needs that. If we do not zero it, subsequent bind() will fail.
   * Also, all-zeroes in the socket address means binding to all addresses
   * for both IPv4 and IPv6 (INADDR_ANY and IN6ADDR_ANY_INIT). */
  memset(so, 0, sizeof(*so));
  so->lsa.sin.sin_family = AF_INET;
  *ip_version = 0;

  /* Initialize len as invalid. */
  port = 0;
  len = 0;

  /* Test for different ways to format this string */
  if (sscanf(vec->ptr,
             "%u.%u.%u.%u:%u%n",
             &a,
             &b,
             &c,
             &d,
             &port,
             &len) // NOLINT(cert-err34-c) 'sscanf' used to convert a string
                   // to an integer value, but function will not report
                   // conversion errors; consider using 'strtol' instead
      == 5) {
    /* Bind to a specific IPv4 address, e.g. 192.168.1.5:8080 */
    so->lsa.sin.sin_addr.s_addr =
        htonl((a << 24) | (b << 16) | (c << 8) | d);
    so->lsa.sin.sin_port = htons((uint16_t)port);
    *ip_version = 4;

#if defined(USE_IPV6)
  } else if (sscanf(vec->ptr, "[%49[^]]]:%u%n", buf, &port, &len) == 2
             && ((size_t)len <= vec->len)
             && mg_inet_pton(
                    AF_INET6, buf, &so->lsa.sin6, sizeof(so->lsa.sin6), 0)) {
    /* IPv6 address, examples: see above */
    /* so->lsa.sin6.sin6_family = AF_INET6; already set by mg_inet_pton
     */
    so->lsa.sin6.sin6_port = htons((uint16_t)port);
    *ip_version = 6;
#endif

  } else if ((vec->ptr[0] == '+')
             && (sscanf(vec->ptr + 1, "%u%n", &port, &len)
                 == 1)) { // NOLINT(cert-err34-c) 'sscanf' used to convert a
                        // string to an integer value, but function will not
                        // report conversion errors; consider using 'strtol'
                        // instead

    /* Port is specified with a +, bind to IPv6 and IPv4, INADDR_ANY */
    /* Add 1 to len for the + character we skipped before */
    len++;

#if defined(USE_IPV6)
    /* Set socket family to IPv6, do not use IPV6_V6ONLY */
    so->lsa.sin6.sin6_family = AF_INET6;
    so->lsa.sin6.sin6_port = htons((uint16_t)port);
    *ip_version = 4 + 6;
#else
    /* Bind to IPv4 only, since IPv6 is not built in. */
    so->lsa.sin.sin_port = htons((uint16_t)port);
    *ip_version = 4;
#endif

  } else if (is_valid_port(portUL = strtoul(vec->ptr, &endptr, 0))
             && (vec->ptr != endptr)) {
    len = (int)(endptr - vec->ptr);
    port = (uint16_t)portUL;
    /* If only port is specified, bind to IPv4, INADDR_ANY */
    so->lsa.sin.sin_port = htons((uint16_t)port);
    *ip_version = 4;

  } else if ((cb = strchr(vec->ptr, ':')) != NULL) {
    /* String could be a hostname. This check algorithm
     * will only work for RFC 952 compliant hostnames,
     * starting with a letter, containing only letters,
     * digits and hyphen ('-'). Newer specs may allow
     * more, but this is not guaranteed here, since it
     * may interfere with rules for port option lists. */

    /* According to RFC 1035, hostnames are restricted to 255 characters
     * in total (63 between two dots). */
    char hostname[256];
    size_t hostnlen = (size_t)(cb - vec->ptr);

    if ((hostnlen >= vec->len) || (hostnlen >= sizeof(hostname))) {
      /* This would be invalid in any case */
      *ip_version = 0;
      return 0;
    }

    mg_strlcpy(hostname, vec->ptr, hostnlen + 1);

    if (mg_inet_pton(
            AF_INET, hostname, &so->lsa.sin, sizeof(so->lsa.sin), 1)) {
      if (sscanf(cb + 1, "%u%n", &port, &len)
          == 1) { // NOLINT(cert-err34-c) 'sscanf' used to convert a
                // string to an integer value, but function will not
                // report conversion errors; consider using 'strtol'
                // instead
        *ip_version = 4;
        so->lsa.sin.sin_port = htons((uint16_t)port);
        len += (int)(hostnlen + 1);
      } else {
        len = 0;
      }
#if defined(USE_IPV6)
    } else if (mg_inet_pton(AF_INET6,
                            hostname,
                            &so->lsa.sin6,
                            sizeof(so->lsa.sin6),
                            1)) {
      if (sscanf(cb + 1, "%u%n", &port, &len) == 1) {
        *ip_version = 6;
        so->lsa.sin6.sin6_port = htons((uint16_t)port);
        len += (int)(hostnlen + 1);
      } else {
        len = 0;
      }
#endif
    } else {
      len = 0;
    }

#if defined(USE_X_DOM_SOCKET)

  } else if (vec->ptr[0] == 'x') {
    /* unix (linux) domain socket */
    if (vec->len < sizeof(so->lsa.sun.sun_path)) {
      len = vec->len;
      so->lsa.sun.sun_family = AF_UNIX;
      memset(so->lsa.sun.sun_path, 0, sizeof(so->lsa.sun.sun_path));
      memcpy(so->lsa.sun.sun_path, (char *)vec->ptr + 1, vec->len - 1);
      port = 0;
      *ip_version = 99;
    } else {
      /* String too long */
      len = 0;
    }
#endif

  } else {
    /* Parsing failure. */
    len = 0;
  }

  /* sscanf and the option splitting code ensure the following condition
   * Make sure the port is valid and vector ends with the port, 's' or 'r' */
  if ((len > 0) && is_valid_port(port)
      && (((size_t)len == vec->len) || (((size_t)len + 1) == vec->len))) {
    /* Next character after the port number */
    ch = ((size_t)len < vec->len) ? vec->ptr[len] : '\0';
    so->is_ssl = (ch == 's');
    so->ssl_redir = (ch == 'r');
    if ((ch == '\0') || (ch == 's') || (ch == 'r')) {
      return 1;
    }
  }

  /* Reset ip_version to 0 if there is an error */
  *ip_version = 0;
  return 0;
}


/* Is there any SSL port in use? */
static int
is_ssl_port_used(const char *ports)
{
  if (ports) {
    /* There are several different allowed syntax variants:
     * - "80" for a single port using every network interface
     * - "localhost:80" for a single port using only localhost
     * - "80,localhost:8080" for two ports, one bound to localhost
     * - "80,127.0.0.1:8084,[::1]:8086" for three ports, one bound
     *   to IPv4 localhost, one to IPv6 localhost
     * - "+80" use port 80 for IPv4 and IPv6
     * - "+80r,+443s" port 80 (HTTP) is a redirect to port 443 (HTTPS),
     *   for both: IPv4 and IPv4
     * - "+443s,localhost:8080" port 443 (HTTPS) for every interface,
     *   additionally port 8080 bound to localhost connections
     *
     * If we just look for 's' anywhere in the string, "localhost:80"
     * will be detected as SSL (false positive).
     * Looking for 's' after a digit may cause false positives in
     * "my24service:8080".
     * Looking from 's' backward if there are only ':' and numbers
     * before will not work for "24service:8080" (non SSL, port 8080)
     * or "24s" (SSL, port 24).
     *
     * Remark: Initially hostnames were not allowed to start with a
     * digit (according to RFC 952), this was allowed later (RFC 1123,
     * Section 2.1).
     *
     * To get this correct, the entire string must be parsed as a whole,
     * reading it as a list element for element and parsing with an
     * algorithm equivalent to parse_port_string.
     *
     * In fact, we use local interface names here, not arbitrary
     * hostnames, so in most cases the only name will be "localhost".
     *
     * So, for now, we use this simple algorithm, that may still return
     * a false positive in bizarre cases.
     */
    int i;
    int portslen = (int)strlen(ports);
    char prevIsNumber = 0;

    for (i = 0; i < portslen; i++) {
      if (prevIsNumber && (ports[i] == 's' || ports[i] == 'r')) {
        return 1;
      }
      if (ports[i] >= '0' && ports[i] <= '9') {
        prevIsNumber = 1;
      } else {
        prevIsNumber = 0;
      }
    }
  }
  return 0;
}


static int
set_ports_option(struct mg_context *phys_ctx)
{
  const char *list;
  int on = 1;
#if defined(USE_IPV6)
  int off = 0;
#endif
  struct vec vec;
  struct socket so, *ptr;

  struct mg_pollfd *pfd;
  union usa usa;
  socklen_t len;
  int ip_version;

  int portsTotal = 0;
  int portsOk = 0;

  const char *opt_txt;
  long opt_listen_backlog;

  if (!phys_ctx) {
    return 0;
  }

  memset(&so, 0, sizeof(so));
  memset(&usa, 0, sizeof(usa));
  len = sizeof(usa);
  list = phys_ctx->dd.config[LISTENING_PORTS];

  while ((list = next_option(list, &vec, NULL)) != NULL) {

    portsTotal++;

    if (!parse_port_string(&vec, &so, &ip_version)) {
      mg_cry_ctx_internal(
          phys_ctx,
          "%.*s: invalid port spec (entry %i). Expecting list of: %s",
          (int)vec.len,
          vec.ptr,
          portsTotal,
          "[IP_ADDRESS:]PORT[s|r]");
      continue;
    }

#if !defined(NO_SSL)
    if (so.is_ssl && phys_ctx->dd.ssl_ctx == NULL) {

      mg_cry_ctx_internal(phys_ctx,
                          "Cannot add SSL socket (entry %i)",
                          portsTotal);
      continue;
    }
#endif
    /* Create socket. */
    /* For a list of protocol numbers (e.g., TCP==6) see:
     * https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
     */
    if ((so.sock =
             socket(so.lsa.sa.sa_family,
                    SOCK_STREAM,
                    (ip_version == 99) ? (/* LOCAL */ 0) : (/* TCP */ 6)))
        == INVALID_SOCKET) {

      mg_cry_ctx_internal(phys_ctx,
                          "cannot create socket (entry %i)",
                          portsTotal);
      continue;
    }

#if defined(_WIN32)
    /* Windows SO_REUSEADDR lets many procs binds to a
     * socket, SO_EXCLUSIVEADDRUSE makes the bind fail
     * if someone already has the socket -- DTL */
    /* NOTE: If SO_EXCLUSIVEADDRUSE is used,
     * Windows might need a few seconds before
     * the same port can be used again in the
     * same process, so a short Sleep may be
     * required between mg_stop and mg_start.
     */
    if (setsockopt(so.sock,
                   SOL_SOCKET,
                   SO_EXCLUSIVEADDRUSE,
                   (SOCK_OPT_TYPE)&on,
                   sizeof(on))
        != 0) {

      /* Set reuse option, but don't abort on errors. */
      mg_cry_ctx_internal(
          phys_ctx,
          "cannot set socket option SO_EXCLUSIVEADDRUSE (entry %i)",
          portsTotal);
    }
#else
    if (setsockopt(so.sock,
                   SOL_SOCKET,
                   SO_REUSEADDR,
                   (SOCK_OPT_TYPE)&on,
                   sizeof(on))
        != 0) {

      /* Set reuse option, but don't abort on errors. */
      mg_cry_ctx_internal(
          phys_ctx,
          "cannot set socket option SO_REUSEADDR (entry %i)",
          portsTotal);
    }
#endif

#if defined(USE_X_DOM_SOCKET)
    if (ip_version == 99) {
      /* Unix domain socket */
    } else
#endif

        if (ip_version > 4) {
      /* Could be 6 for IPv6 onlyor 10 (4+6) for IPv4+IPv6 */
#if defined(USE_IPV6)
      if (ip_version > 6) {
        if (so.lsa.sa.sa_family == AF_INET6
            && setsockopt(so.sock,
                          IPPROTO_IPV6,
                          IPV6_V6ONLY,
                          (void *)&off,
                          sizeof(off))
                   != 0) {

          /* Set IPv6 only option, but don't abort on errors. */
          mg_cry_ctx_internal(phys_ctx,
                              "cannot set socket option "
                              "IPV6_V6ONLY=off (entry %i)",
                              portsTotal);
        }
      } else {
        if (so.lsa.sa.sa_family == AF_INET6
            && setsockopt(so.sock,
                          IPPROTO_IPV6,
                          IPV6_V6ONLY,
                          (void *)&on,
                          sizeof(on))
                   != 0) {

          /* Set IPv6 only option, but don't abort on errors. */
          mg_cry_ctx_internal(phys_ctx,
                              "cannot set socket option "
                              "IPV6_V6ONLY=on (entry %i)",
                              portsTotal);
        }
      }
#else
      mg_cry_ctx_internal(phys_ctx, "%s", "IPv6 not available");
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
#endif
    }

    if (so.lsa.sa.sa_family == AF_INET) {

      len = sizeof(so.lsa.sin);
      if (bind(so.sock, &so.lsa.sa, len) != 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "cannot bind to %.*s: %d (%s)",
                            (int)vec.len,
                            vec.ptr,
                            (int)ERRNO,
                            strerror(errno));
        closesocket(so.sock);
        so.sock = INVALID_SOCKET;
        continue;
      }
    }
#if defined(USE_IPV6)
    else if (so.lsa.sa.sa_family == AF_INET6) {

      len = sizeof(so.lsa.sin6);
      if (bind(so.sock, &so.lsa.sa, len) != 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "cannot bind to IPv6 %.*s: %d (%s)",
                            (int)vec.len,
                            vec.ptr,
                            (int)ERRNO,
                            strerror(errno));
        closesocket(so.sock);
        so.sock = INVALID_SOCKET;
        continue;
      }
    }
#endif
#if defined(USE_X_DOM_SOCKET)
    else if (so.lsa.sa.sa_family == AF_UNIX) {

      len = sizeof(so.lsa.sun);
      if (bind(so.sock, &so.lsa.sa, len) != 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "cannot bind to unix socket %s: %d (%s)",
                            so.lsa.sun.sun_path,
                            (int)ERRNO,
                            strerror(errno));
        closesocket(so.sock);
        so.sock = INVALID_SOCKET;
        continue;
      }
    }
#endif
    else {
      mg_cry_ctx_internal(
          phys_ctx,
          "cannot bind: address family not supported (entry %i)",
          portsTotal);
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    opt_txt = phys_ctx->dd.config[LISTEN_BACKLOG_SIZE];
    opt_listen_backlog = strtol(opt_txt, NULL, 10);
    if ((opt_listen_backlog > INT_MAX) || (opt_listen_backlog < 1)) {
      mg_cry_ctx_internal(phys_ctx,
                          "%s value \"%s\" is invalid",
                          config_options[LISTEN_BACKLOG_SIZE].name,
                          opt_txt);
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    if (listen(so.sock, (int)opt_listen_backlog) != 0) {

      mg_cry_ctx_internal(phys_ctx,
                          "cannot listen to %.*s: %d (%s)",
                          (int)vec.len,
                          vec.ptr,
                          (int)ERRNO,
                          strerror(errno));
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    if ((getsockname(so.sock, &(usa.sa), &len) != 0)
        || (usa.sa.sa_family != so.lsa.sa.sa_family)) {

      int err = (int)ERRNO;
      mg_cry_ctx_internal(phys_ctx,
                          "call to getsockname failed %.*s: %d (%s)",
                          (int)vec.len,
                          vec.ptr,
                          err,
                          strerror(errno));
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    /* Update lsa port in case of random free ports */
#if defined(USE_IPV6)
    if (so.lsa.sa.sa_family == AF_INET6) {
      so.lsa.sin6.sin6_port = usa.sin6.sin6_port;
    } else
#endif
    {
      so.lsa.sin.sin_port = usa.sin.sin_port;
    }

    if ((ptr = (struct socket *)
             mg_realloc_ctx(phys_ctx->listening_sockets,
                            (phys_ctx->num_listening_sockets + 1)
                                * sizeof(phys_ctx->listening_sockets[0]),
                            phys_ctx))
        == NULL) {

      mg_cry_ctx_internal(phys_ctx, "%s", "Out of memory");
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    if ((pfd = (struct mg_pollfd *)
             mg_realloc_ctx(phys_ctx->listening_socket_fds,
                            (phys_ctx->num_listening_sockets + 1)
                                * sizeof(phys_ctx->listening_socket_fds[0]),
                            phys_ctx))
        == NULL) {

      mg_cry_ctx_internal(phys_ctx, "%s", "Out of memory");
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      mg_free(ptr);
      continue;
    }

    set_close_on_exec(so.sock, NULL, phys_ctx);
    phys_ctx->listening_sockets = ptr;
    phys_ctx->listening_sockets[phys_ctx->num_listening_sockets] = so;
    phys_ctx->listening_socket_fds = pfd;
    phys_ctx->num_listening_sockets++;
    portsOk++;
  }

  if (portsOk != portsTotal) {
    close_all_listening_sockets(phys_ctx);
    portsOk = 0;
  }

  return portsOk;
}


static const char *
header_val(const struct mg_connection *conn, const char *header)
{
  const char *header_value;

  if ((header_value = mg_get_header(conn, header)) == NULL) {
    return "-";
  } else {
    return header_value;
  }
}


#if defined(MG_EXTERNAL_FUNCTION_log_access)
#include "external_log_access.inl"
#elif !defined(NO_FILESYSTEMS)

static void
log_access(const struct mg_connection *conn)
{
  const struct mg_request_info *ri;
  struct mg_file fi;
  char date[64], src_addr[IP_ADDR_STR_LEN];
#if defined(REENTRANT_TIME)
  struct tm _tm;
  struct tm *tm = &_tm;
#else
  struct tm *tm;
#endif

  const char *referer;
  const char *user_agent;

  char log_buf[4096];

  if (!conn || !conn->dom_ctx) {
    return;
  }

  /* Set log message to "empty" */
  log_buf[0] = 0;

#if defined(USE_LUA)
  if (conn->phys_ctx->lua_bg_log_available) {
    int ret;
    struct mg_context *ctx = conn->phys_ctx;
    lua_State *lstate = (lua_State *)ctx->lua_background_state;
    pthread_mutex_lock(&ctx->lua_bg_mutex);
    /* call "log()" in Lua */
    lua_getglobal(lstate, "log");
    prepare_lua_request_info_inner(conn, lstate);
    push_lua_response_log_data(conn, lstate);

    ret = lua_pcall(lstate, /* args */ 2, /* results */ 1, 0);
    if (ret == 0) {
      int t = lua_type(lstate, -1);
      if (t == LUA_TBOOLEAN) {
        if (lua_toboolean(lstate, -1) == 0) {
          /* log() returned false: do not log */
          pthread_mutex_unlock(&ctx->lua_bg_mutex);
          return;
        }
        /* log returned true: continue logging */
      } else if (t == LUA_TSTRING) {
        size_t len;
        const char *txt = lua_tolstring(lstate, -1, &len);
        if ((len == 0) || (*txt == 0)) {
          /* log() returned empty string: do not log */
          pthread_mutex_unlock(&ctx->lua_bg_mutex);
          return;
        }
        /* Copy test from Lua into log_buf */
        if (len >= sizeof(log_buf)) {
          len = sizeof(log_buf) - 1;
        }
        memcpy(log_buf, txt, len);
        log_buf[len] = 0;
      }
    } else {
      lua_cry(conn, ret, lstate, "lua_background_script", "log");
    }
    pthread_mutex_unlock(&ctx->lua_bg_mutex);
  }
#endif

  if (conn->dom_ctx->config[ACCESS_LOG_FILE] != NULL) {
    if (mg_fopen(conn,
                 conn->dom_ctx->config[ACCESS_LOG_FILE],
                 MG_FOPEN_MODE_APPEND,
                 &fi)
        == 0) {
      fi.access.fp = NULL;
    }
  } else {
    fi.access.fp = NULL;
  }

  /* Log is written to a file and/or a callback. If both are not set,
   * executing the rest of the function is pointless. */
  if ((fi.access.fp == NULL)
      && (conn->phys_ctx->callbacks.log_access == NULL)) {
    return;
  }

  /* If we did not get a log message from Lua, create it here. */
  if (!log_buf[0]) {
#if defined(REENTRANT_TIME)
    localtime_r(&conn->conn_birth_time, tm);
#else
    tm = localtime(&conn->conn_birth_time);
#endif
    if (tm != NULL) {
      strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z", tm);
    } else {
      mg_strlcpy(date, "01/Jan/1970:00:00:00 +0000", sizeof(date));
    }

    ri = &conn->request_info;

    sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
    referer = header_val(conn, "Referer");
    user_agent = header_val(conn, "User-Agent");

    mg_snprintf(conn,
                NULL, /* Ignore truncation in access log */
                log_buf,
                sizeof(log_buf),
                "%s - %s [%s] \"%s %s%s%s HTTP/%s\" %d %" INT64_FMT
                " %s %s",
                src_addr,
                (ri->remote_user == NULL) ? "-" : ri->remote_user,
                date,
                ri->request_method ? ri->request_method : "-",
                ri->request_uri ? ri->request_uri : "-",
                ri->query_string ? "?" : "",
                ri->query_string ? ri->query_string : "",
                ri->http_version,
                conn->status_code,
                conn->num_bytes_sent,
                referer,
                user_agent);
  }

  /* Here we have a log message in log_buf. Call the callback */
  if (conn->phys_ctx->callbacks.log_access) {
    if (conn->phys_ctx->callbacks.log_access(conn, log_buf)) {
      /* do not log if callback returns non-zero */
      if (fi.access.fp) {
        mg_fclose(&fi.access);
      }
      return;
    }
  }

  /* Store in file */
  if (fi.access.fp) {
    int ok = 1;
    flockfile(fi.access.fp);
    if (fprintf(fi.access.fp, "%s\n", log_buf) < 1) {
      ok = 0;
    }
    if (fflush(fi.access.fp) != 0) {
      ok = 0;
    }
    funlockfile(fi.access.fp);
    if (mg_fclose(&fi.access) != 0) {
      ok = 0;
    }
    if (!ok) {
      mg_cry_internal(conn,
                      "Error writing log file %s",
                      conn->dom_ctx->config[ACCESS_LOG_FILE]);
    }
  }
}
#else
#error "Either enable filesystems or provide a custom log_access implementation"
#endif /* Externally provided function */


/* Verify given socket address against the ACL.
 * Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
 */
static int
check_acl(struct mg_context *phys_ctx, const union usa *sa)
{
  int allowed, flag, matched;
  struct vec vec;

  if (phys_ctx) {
    const char *list = phys_ctx->dd.config[ACCESS_CONTROL_LIST];

    /* If any ACL is set, deny by default */
    allowed = (list == NULL) ? '+' : '-';

    while ((list = next_option(list, &vec, NULL)) != NULL) {
      flag = vec.ptr[0];
      matched = -1;
      if ((vec.len > 0) && ((flag == '+') || (flag == '-'))) {
        vec.ptr++;
        vec.len--;
        matched = parse_match_net(&vec, sa, 1);
      }
      if (matched < 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: subnet must be [+|-]IP-addr[/x]",
                            __func__);
        return -1;
      }
      if (matched) {
        allowed = flag;
      }
    }

    return allowed == '+';
  }
  return -1;
}


#if !defined(_WIN32) && !defined(__ZEPHYR__)
static int
set_uid_option(struct mg_context *phys_ctx)
{
  int success = 0;

  if (phys_ctx) {
    /* We are currently running as curr_uid. */
    const uid_t curr_uid = getuid();
    /* If set, we want to run as run_as_user. */
    const char *run_as_user = phys_ctx->dd.config[RUN_AS_USER];
    const struct passwd *to_pw = NULL;

    if ((run_as_user != NULL) && (to_pw = getpwnam(run_as_user)) == NULL) {
      /* run_as_user does not exist on the system. We can't proceed
       * further. */
      mg_cry_ctx_internal(phys_ctx,
                          "%s: unknown user [%s]",
                          __func__,
                          run_as_user);
    } else if ((run_as_user == NULL) || (curr_uid == to_pw->pw_uid)) {
      /* There was either no request to change user, or we're already
       * running as run_as_user. Nothing else to do.
       */
      success = 1;
    } else {
      /* Valid change request.  */
      if (setgid(to_pw->pw_gid) == -1) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: setgid(%s): %s",
                            __func__,
                            run_as_user,
                            strerror(errno));
      } else if (setgroups(0, NULL) == -1) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: setgroups(): %s",
                            __func__,
                            strerror(errno));
      } else if (setuid(to_pw->pw_uid) == -1) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: setuid(%s): %s",
                            __func__,
                            run_as_user,
                            strerror(errno));
      } else {
        success = 1;
      }
    }
  }

  return success;
}
#endif /* !_WIN32 */


static void
tls_dtor(void *key)
{
  struct mg_workerTLS *tls = (struct mg_workerTLS *)key;
  /* key == pthread_getspecific(sTlsKey); */

  if (tls) {
    if (tls->is_master == 2) {
      tls->is_master = -3; /* Mark memory as dead */
      mg_free(tls);
    }
  }
  pthread_setspecific(sTlsKey, NULL);
}


#if defined(USE_MBEDTLS)
/* Check if SSL is required.
 * If so, set up ctx->ssl_ctx pointer. */
static int
mg_sslctx_init(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
  if (!phys_ctx) {
    return 0;
  }

  if (!dom_ctx) {
    dom_ctx = &(phys_ctx->dd);
  }

  if (!is_ssl_port_used(dom_ctx->config[LISTENING_PORTS])) {
    /* No SSL port is set. No need to setup SSL. */
    return 1;
  }

  dom_ctx->ssl_ctx = (SSL_CTX *)mg_calloc(1, sizeof(*dom_ctx->ssl_ctx));
  if (dom_ctx->ssl_ctx == NULL) {
    fprintf(stderr, "ssl_ctx malloc failed\n");
    return 0;
  }

  return mbed_sslctx_init(dom_ctx->ssl_ctx, dom_ctx->config[SSL_CERTIFICATE])
                 == 0
             ? 1
             : 0;
}

#elif !defined(NO_SSL)

static int ssl_use_pem_file(struct mg_context *phys_ctx,
                            struct mg_domain_context *dom_ctx,
                            const char *pem,
                            const char *chain);
static const char *ssl_error(void);


static int
refresh_trust(struct mg_connection *conn)
{
  struct stat cert_buf;
  int64_t t = 0;
  const char *pem;
  const char *chain;
  int should_verify_peer;

  if ((pem = conn->dom_ctx->config[SSL_CERTIFICATE]) == NULL) {
    /* If pem is NULL and conn->phys_ctx->callbacks.init_ssl is not,
     * refresh_trust still can not work. */
    return 0;
  }
  chain = conn->dom_ctx->config[SSL_CERTIFICATE_CHAIN];
  if (chain == NULL) {
    /* pem is not NULL here */
    chain = pem;
  }
  if (*chain == 0) {
    chain = NULL;
  }

  if (stat(pem, &cert_buf) != -1) {
    t = (int64_t)cert_buf.st_mtime;
  }

  mg_lock_context(conn->phys_ctx);
  if ((t != 0) && (conn->dom_ctx->ssl_cert_last_mtime != t)) {
    conn->dom_ctx->ssl_cert_last_mtime = t;

    should_verify_peer = 0;
    if (conn->dom_ctx->config[SSL_DO_VERIFY_PEER] != NULL) {
      if (mg_strcasecmp(conn->dom_ctx->config[SSL_DO_VERIFY_PEER], "yes")
          == 0) {
        should_verify_peer = 1;
      } else if (mg_strcasecmp(conn->dom_ctx->config[SSL_DO_VERIFY_PEER],
                               "optional")
                 == 0) {
        should_verify_peer = 1;
      }
    }

    if (should_verify_peer) {
      char *ca_path = conn->dom_ctx->config[SSL_CA_PATH];
      char *ca_file = conn->dom_ctx->config[SSL_CA_FILE];
      if (SSL_CTX_load_verify_locations(conn->dom_ctx->ssl_ctx,
                                        ca_file,
                                        ca_path)
          != 1) {
        mg_unlock_context(conn->phys_ctx);
        mg_cry_ctx_internal(
            conn->phys_ctx,
            "SSL_CTX_load_verify_locations error: %s "
            "ssl_verify_peer requires setting "
            "either ssl_ca_path or ssl_ca_file. Is any of them "
            "present in "
            "the .conf file?",
            ssl_error());
        return 0;
      }
    }

    if (ssl_use_pem_file(conn->phys_ctx, conn->dom_ctx, pem, chain) == 0) {
      mg_unlock_context(conn->phys_ctx);
      return 0;
    }
  }
  mg_unlock_context(conn->phys_ctx);

  return 1;
}

#if defined(OPENSSL_API_1_1)
#else
static pthread_mutex_t *ssl_mutexes;
#endif /* OPENSSL_API_1_1 */

static int
sslize(struct mg_connection *conn,
       int (*func)(SSL *),
       const struct mg_client_options *client_options)
{
  int ret, err;
  int short_trust;
  unsigned timeout = 1024;
  unsigned i;

  if (!conn) {
    return 0;
  }

  short_trust =
      (conn->dom_ctx->config[SSL_SHORT_TRUST] != NULL)
      && (mg_strcasecmp(conn->dom_ctx->config[SSL_SHORT_TRUST], "yes") == 0);

  if (short_trust) {
    int trust_ret = refresh_trust(conn);
    if (!trust_ret) {
      return trust_ret;
    }
  }

  mg_lock_context(conn->phys_ctx);
  conn->ssl = SSL_new(conn->dom_ctx->ssl_ctx);
  mg_unlock_context(conn->phys_ctx);
  if (conn->ssl == NULL) {
    mg_cry_internal(conn, "sslize error: %s", ssl_error());
    OPENSSL_REMOVE_THREAD_STATE();
    return 0;
  }
  SSL_set_app_data(conn->ssl, (char *)conn);

  ret = SSL_set_fd(conn->ssl, conn->client.sock);
  if (ret != 1) {
    mg_cry_internal(conn, "sslize error: %s", ssl_error());
    SSL_free(conn->ssl);
    conn->ssl = NULL;
    OPENSSL_REMOVE_THREAD_STATE();
    return 0;
  }

  if (client_options) {
    if (client_options->host_name) {
      SSL_set_tlsext_host_name(conn->ssl, client_options->host_name);
    }
  }

  /* Reuse the request timeout for the SSL_Accept/SSL_connect timeout  */
  if (conn->dom_ctx->config[REQUEST_TIMEOUT]) {
    /* NOTE: The loop below acts as a back-off, so we can end
     * up sleeping for more (or less) than the REQUEST_TIMEOUT. */
    int to = atoi(conn->dom_ctx->config[REQUEST_TIMEOUT]);
    if (to >= 0) {
      timeout = (unsigned)to;
    }
  }

  /* SSL functions may fail and require to be called again:
   * see https://www.openssl.org/docs/manmaster/ssl/SSL_get_error.html
   * Here "func" could be SSL_connect or SSL_accept. */
  for (i = 0; i <= timeout; i += 50) {
    ERR_clear_error();
    /* conn->dom_ctx may be changed here (see ssl_servername_callback) */
    ret = func(conn->ssl);
    if (ret != 1) {
      err = SSL_get_error(conn->ssl, ret);
      if ((err == SSL_ERROR_WANT_CONNECT)
          || (err == SSL_ERROR_WANT_ACCEPT)
          || (err == SSL_ERROR_WANT_READ) || (err == SSL_ERROR_WANT_WRITE)
          || (err == SSL_ERROR_WANT_X509_LOOKUP)) {
        if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
          /* Don't wait if the server is going to be stopped. */
          break;
        }
        if (err == SSL_ERROR_WANT_X509_LOOKUP) {
          /* Simply retry the function call. */
          mg_sleep(50);
        } else {
          /* Need to retry the function call "later".
           * See https://linux.die.net/man/3/ssl_get_error
           * This is typical for non-blocking sockets. */
          struct mg_pollfd pfd;
          int pollres;
          pfd.fd = conn->client.sock;
          pfd.events = ((err == SSL_ERROR_WANT_CONNECT)
                        || (err == SSL_ERROR_WANT_WRITE))
                           ? POLLOUT
                           : POLLIN;
          pollres =
              mg_poll(&pfd, 1, 50, &(conn->phys_ctx->stop_flag));
          if (pollres < 0) {
            /* Break if error occurred (-1)
             * or server shutdown (-2) */
            break;
          }
        }

      } else if (err == SSL_ERROR_SYSCALL) {
        /* This is an IO error. Look at errno. */
        mg_cry_internal(conn, "SSL syscall error %i", ERRNO);
        break;

      } else {
        /* This is an SSL specific error, e.g. SSL_ERROR_SSL */
        mg_cry_internal(conn, "sslize error: %s", ssl_error());
        break;
      }

    } else {
      /* success */
      break;
    }
  }
  ERR_clear_error();

  if (ret != 1) {
    SSL_free(conn->ssl);
    conn->ssl = NULL;
    OPENSSL_REMOVE_THREAD_STATE();
    return 0;
  }

  return 1;
}


/* Return OpenSSL error message (from CRYPTO lib) */
static const char *
ssl_error(void)
{
  unsigned long err;
  err = ERR_get_error();
  return ((err == 0) ? "" : ERR_error_string(err, NULL));
}


static int
hexdump2string(void *mem, int memlen, char *buf, int buflen)
{
  int i;
  const char hexdigit[] = "0123456789abcdef";

  if ((memlen <= 0) || (buflen <= 0)) {
    return 0;
  }
  if (buflen < (3 * memlen)) {
    return 0;
  }

  for (i = 0; i < memlen; i++) {
    if (i > 0) {
      buf[3 * i - 1] = ' ';
    }
    buf[3 * i] = hexdigit[(((uint8_t *)mem)[i] >> 4) & 0xF];
    buf[3 * i + 1] = hexdigit[((uint8_t *)mem)[i] & 0xF];
  }
  buf[3 * memlen - 1] = 0;

  return 1;
}


static int
ssl_get_client_cert_info(const struct mg_connection *conn,
                         struct mg_client_cert *client_cert)
{
  X509 *cert = SSL_get_peer_certificate(conn->ssl);
  if (cert) {
    char str_buf[1024];
    unsigned char buf[256];
    char *str_serial = NULL;
    unsigned int ulen;
    int ilen;
    unsigned char *tmp_buf;
    unsigned char *tmp_p;

    /* Handle to algorithm used for fingerprint */
    const EVP_MD *digest = EVP_get_digestbyname("sha1");

    /* Get Subject and issuer */
    X509_NAME *subj = X509_get_subject_name(cert);
    X509_NAME *iss = X509_get_issuer_name(cert);

    /* Get serial number */
    ASN1_INTEGER *serial = X509_get_serialNumber(cert);

    /* Translate serial number to a hex string */
    BIGNUM *serial_bn = ASN1_INTEGER_to_BN(serial, NULL);
    if (serial_bn) {
      str_serial = BN_bn2hex(serial_bn);
      BN_free(serial_bn);
    }
    client_cert->serial =
        str_serial ? mg_strdup_ctx(str_serial, conn->phys_ctx) : NULL;

    /* Translate subject and issuer to a string */
    (void)X509_NAME_oneline(subj, str_buf, (int)sizeof(str_buf));
    client_cert->subject = mg_strdup_ctx(str_buf, conn->phys_ctx);
    (void)X509_NAME_oneline(iss, str_buf, (int)sizeof(str_buf));
    client_cert->issuer = mg_strdup_ctx(str_buf, conn->phys_ctx);

    /* Calculate SHA1 fingerprint and store as a hex string */
    ulen = 0;

    /* ASN1_digest is deprecated. Do the calculation manually,
     * using EVP_Digest. */
    ilen = i2d_X509(cert, NULL);
    tmp_buf = (ilen > 0)
                  ? (unsigned char *)mg_malloc_ctx((unsigned)ilen + 1,
                                                   conn->phys_ctx)
                  : NULL;
    if (tmp_buf) {
      tmp_p = tmp_buf;
      (void)i2d_X509(cert, &tmp_p);
      if (!EVP_Digest(
              tmp_buf, (unsigned)ilen, buf, &ulen, digest, NULL)) {
        ulen = 0;
      }
      mg_free(tmp_buf);
    }

    if (!hexdump2string(buf, (int)ulen, str_buf, (int)sizeof(str_buf))) {
      *str_buf = 0;
    }
    client_cert->finger = mg_strdup_ctx(str_buf, conn->phys_ctx);

    client_cert->peer_cert = (void *)cert;

    /* Strings returned from bn_bn2hex must be freed using OPENSSL_free,
     * see https://linux.die.net/man/3/bn_bn2hex */
    OPENSSL_free(str_serial);
    return 1;
  }
  return 0;
}


#if defined(OPENSSL_API_1_1)
#else
static void
ssl_locking_callback(int mode, int mutex_num, const char *file, int line)
{
  (void)line;
  (void)file;

  if (mode & 1) {
    /* 1 is CRYPTO_LOCK */
    (void)pthread_mutex_lock(&ssl_mutexes[mutex_num]);
  } else {
    (void)pthread_mutex_unlock(&ssl_mutexes[mutex_num]);
  }
}
#endif /* OPENSSL_API_1_1 */


#if !defined(NO_SSL_DL)
/* Load a DLL/Shared Object with a TLS/SSL implementation. */
static void *
load_tls_dll(char *ebuf,
             size_t ebuf_len,
             const char *dll_name,
             struct ssl_func *sw,
             int *feature_missing)
{
  union {
    void *p;
    void (*fp)(void);
  } u;
  void *dll_handle;
  struct ssl_func *fp;
  int ok;
  int truncated = 0;

  if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL) {
    mg_snprintf(NULL,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s: cannot load %s",
                __func__,
                dll_name);
    return NULL;
  }

  ok = 1;
  for (fp = sw; fp->name != NULL; fp++) {
#if defined(_WIN32)
    /* GetProcAddress() returns pointer to function */
    u.fp = (void (*)(void))dlsym(dll_handle, fp->name);
#else
    /* dlsym() on UNIX returns void *. ISO C forbids casts of data
     * pointers to function pointers. We need to use a union to make a
     * cast. */
    u.p = dlsym(dll_handle, fp->name);
#endif /* _WIN32 */

    /* Set pointer (might be NULL) */
    fp->ptr = u.fp;

    if (u.fp == NULL) {
      DEBUG_TRACE("Missing function: %s\n", fp->name);
      if (feature_missing) {
        feature_missing[fp->required]++;
      }
      if (fp->required == TLS_Mandatory) {
        /* Mandatory function is missing */
        if (ok) {
          /* This is the first missing function.
           * Create a new error message. */
          mg_snprintf(NULL,
                      &truncated,
                      ebuf,
                      ebuf_len,
                      "%s: %s: cannot find %s",
                      __func__,
                      dll_name,
                      fp->name);
          ok = 0;
        } else {
          /* This is yet anothermissing function.
           * Append existing error message. */
          size_t cur_len = strlen(ebuf);
          if (!truncated && ((ebuf_len - cur_len) > 3)) {
            mg_snprintf(NULL,
                        &truncated,
                        ebuf + cur_len,
                        ebuf_len - cur_len - 3,
                        ", %s",
                        fp->name);
            if (truncated) {
              /* If truncated, add "..." */
              strcat(ebuf, "...");
            }
          }
        }
      }
    }
  }

  if (!ok) {
    (void)dlclose(dll_handle);
    return NULL;
  }

  return dll_handle;
}


static void *ssllib_dll_handle;    /* Store the ssl library handle. */
static void *cryptolib_dll_handle; /* Store the crypto library handle. */

#endif /* NO_SSL_DL */


#if defined(SSL_ALREADY_INITIALIZED)
static volatile ptrdiff_t cryptolib_users =
    1; /* Reference counter for crypto library. */
#else
static volatile ptrdiff_t cryptolib_users =
    0; /* Reference counter for crypto library. */
#endif


static int
initialize_openssl(char *ebuf, size_t ebuf_len)
{
#if !defined(OPENSSL_API_1_1) && !defined(OPENSSL_API_3_0)
  int i, num_locks;
  size_t size;
#endif

  if (ebuf_len > 0) {
    ebuf[0] = 0;
  }

#if !defined(NO_SSL_DL)
  if (!cryptolib_dll_handle) {
    memset(tls_feature_missing, 0, sizeof(tls_feature_missing));
    cryptolib_dll_handle = load_tls_dll(
        ebuf, ebuf_len, CRYPTO_LIB, crypto_sw, tls_feature_missing);
    if (!cryptolib_dll_handle) {
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s: error loading library %s",
                  __func__,
                  CRYPTO_LIB);
      DEBUG_TRACE("%s", ebuf);
      return 0;
    }
  }
#endif /* NO_SSL_DL */

  if (mg_atomic_inc(&cryptolib_users) > 1) {
    return 1;
  }

#if !defined(OPENSSL_API_1_1) && !defined(OPENSSL_API_3_0)
  /* Initialize locking callbacks, needed for thread safety.
   * http://www.openssl.org/support/faq.html#PROG1
   */
  num_locks = CRYPTO_num_locks();
  if (num_locks < 0) {
    num_locks = 0;
  }
  size = sizeof(pthread_mutex_t) * ((size_t)(num_locks));

  /* allocate mutex array, if required */
  if (num_locks == 0) {
    /* No mutex array required */
    ssl_mutexes = NULL;
  } else {
    /* Mutex array required - allocate it */
    ssl_mutexes = (pthread_mutex_t *)mg_malloc(size);

    /* Check OOM */
    if (ssl_mutexes == NULL) {
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s: cannot allocate mutexes: %s",
                  __func__,
                  ssl_error());
      DEBUG_TRACE("%s", ebuf);
      return 0;
    }

    /* initialize mutex array */
    for (i = 0; i < num_locks; i++) {
      if (0 != pthread_mutex_init(&ssl_mutexes[i], &pthread_mutex_attr)) {
        mg_snprintf(NULL,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s: error initializing mutex %i of %i",
                    __func__,
                    i,
                    num_locks);
        DEBUG_TRACE("%s", ebuf);
        mg_free(ssl_mutexes);
        return 0;
      }
    }
  }

  CRYPTO_set_locking_callback(&ssl_locking_callback);
  CRYPTO_set_id_callback(&mg_current_thread_id);
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */

#if !defined(NO_SSL_DL)
  if (!ssllib_dll_handle) {
    ssllib_dll_handle =
        load_tls_dll(ebuf, ebuf_len, SSL_LIB, ssl_sw, tls_feature_missing);
    if (!ssllib_dll_handle) {
#if !defined(OPENSSL_API_1_1)
      mg_free(ssl_mutexes);
#endif
      DEBUG_TRACE("%s", ebuf);
      return 0;
    }
  }
#endif /* NO_SSL_DL */

#if (defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0))                     \
    && !defined(NO_SSL_DL)
  /* Initialize SSL library */
  OPENSSL_init_ssl(0, NULL);
  OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS
                       | OPENSSL_INIT_LOAD_CRYPTO_STRINGS,
                   NULL);
#else
  /* Initialize SSL library */
  SSL_library_init();
  SSL_load_error_strings();
#endif

  return 1;
}


static int
ssl_use_pem_file(struct mg_context *phys_ctx,
                 struct mg_domain_context *dom_ctx,
                 const char *pem,
                 const char *chain)
{
  if (SSL_CTX_use_certificate_file(dom_ctx->ssl_ctx, pem, 1) == 0) {
    mg_cry_ctx_internal(phys_ctx,
                        "%s: cannot open certificate file %s: %s",
                        __func__,
                        pem,
                        ssl_error());
    return 0;
  }

  /* could use SSL_CTX_set_default_passwd_cb_userdata */
  if (SSL_CTX_use_PrivateKey_file(dom_ctx->ssl_ctx, pem, 1) == 0) {
    mg_cry_ctx_internal(phys_ctx,
                        "%s: cannot open private key file %s: %s",
                        __func__,
                        pem,
                        ssl_error());
    return 0;
  }

  if (SSL_CTX_check_private_key(dom_ctx->ssl_ctx) == 0) {
    mg_cry_ctx_internal(phys_ctx,
                        "%s: certificate and private key do not match: %s",
                        __func__,
                        pem);
    return 0;
  }

  /* In contrast to OpenSSL, wolfSSL does not support certificate
   * chain files that contain private keys and certificates in
   * SSL_CTX_use_certificate_chain_file.
   * The CivetWeb-Server used pem-Files that contained both information.
   * In order to make wolfSSL work, it is split in two files.
   * One file that contains key and certificate used by the server and
   * an optional chain file for the ssl stack.
   */
  if (chain) {
    if (SSL_CTX_use_certificate_chain_file(dom_ctx->ssl_ctx, chain) == 0) {
      mg_cry_ctx_internal(phys_ctx,
                          "%s: cannot use certificate chain file %s: %s",
                          __func__,
                          chain,
                          ssl_error());
      return 0;
    }
  }
  return 1;
}


#if defined(OPENSSL_API_1_1)
static unsigned long
ssl_get_protocol(int version_id)
{
  long unsigned ret = (long unsigned)SSL_OP_ALL;
  if (version_id > 0)
    ret |= SSL_OP_NO_SSLv2;
  if (version_id > 1)
    ret |= SSL_OP_NO_SSLv3;
  if (version_id > 2)
    ret |= SSL_OP_NO_TLSv1;
  if (version_id > 3)
    ret |= SSL_OP_NO_TLSv1_1;
  if (version_id > 4)
    ret |= SSL_OP_NO_TLSv1_2;
#if defined(SSL_OP_NO_TLSv1_3)
  if (version_id > 5)
    ret |= SSL_OP_NO_TLSv1_3;
#endif
  return ret;
}
#else
static long
ssl_get_protocol(int version_id)
{
  unsigned long ret = (unsigned long)SSL_OP_ALL;
  if (version_id > 0)
    ret |= SSL_OP_NO_SSLv2;
  if (version_id > 1)
    ret |= SSL_OP_NO_SSLv3;
  if (version_id > 2)
    ret |= SSL_OP_NO_TLSv1;
  if (version_id > 3)
    ret |= SSL_OP_NO_TLSv1_1;
  if (version_id > 4)
    ret |= SSL_OP_NO_TLSv1_2;
#if defined(SSL_OP_NO_TLSv1_3)
  if (version_id > 5)
    ret |= SSL_OP_NO_TLSv1_3;
#endif
  return (long)ret;
}
#endif /* OPENSSL_API_1_1 */


/* SSL callback documentation:
 * https://www.openssl.org/docs/man1.1.0/ssl/SSL_set_info_callback.html
 * https://wiki.openssl.org/index.php/Manual:SSL_CTX_set_info_callback(3)
 * https://linux.die.net/man/3/ssl_set_info_callback */
/* Note: There is no "const" for the first argument in the documentation
 * examples, however some (maybe most, but not all) headers of OpenSSL
 * versions / OpenSSL compatibility layers have it. Having a different
 * definition will cause a warning in C and an error in C++. Use "const SSL
 * *", while automatic conversion from "SSL *" works for all compilers,
 * but not other way around */
static void
ssl_info_callback(const SSL *ssl, int what, int ret)
{
  (void)ret;

  if (what & SSL_CB_HANDSHAKE_START) {
    SSL_get_app_data(ssl);
  }
  if (what & SSL_CB_HANDSHAKE_DONE) {
    /* TODO: check for openSSL 1.1 */
    //#define SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS 0x0001
    // ssl->s3->flags |= SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS;
  }
}


static int
ssl_servername_callback(SSL *ssl, int *ad, void *arg)
{
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
#endif /* defined(GCC_DIAGNOSTIC) */

  /* We used an aligned pointer in SSL_set_app_data */
  struct mg_connection *conn = (struct mg_connection *)SSL_get_app_data(ssl);

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */

  const char *servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);

  (void)ad;
  (void)arg;

  if ((conn == NULL) || (conn->phys_ctx == NULL)) {
    DEBUG_ASSERT(0);
    return SSL_TLSEXT_ERR_NOACK;
  }
  conn->dom_ctx = &(conn->phys_ctx->dd);

  /* Old clients (Win XP) will not support SNI. Then, there
   * is no server name available in the request - we can
   * only work with the default certificate.
   * Multiple HTTPS hosts on one IP+port are only possible
   * with a certificate containing all alternative names.
   */
  if ((servername == NULL) || (*servername == 0)) {
    DEBUG_TRACE("%s", "SSL connection not supporting SNI");
    mg_lock_context(conn->phys_ctx);
    SSL_set_SSL_CTX(ssl, conn->dom_ctx->ssl_ctx);
    mg_unlock_context(conn->phys_ctx);
    return SSL_TLSEXT_ERR_NOACK;
  }

  DEBUG_TRACE("TLS connection to host %s", servername);

  while (conn->dom_ctx) {
    if (!mg_strcasecmp(servername,
                       conn->dom_ctx->config[AUTHENTICATION_DOMAIN])) {
      /* Found matching domain */
      DEBUG_TRACE("TLS domain %s found",
                  conn->dom_ctx->config[AUTHENTICATION_DOMAIN]);
      break;
    }
    mg_lock_context(conn->phys_ctx);
    conn->dom_ctx = conn->dom_ctx->next;
    mg_unlock_context(conn->phys_ctx);
  }

  if (conn->dom_ctx == NULL) {
    /* Default domain */
    DEBUG_TRACE("TLS default domain %s used",
                conn->phys_ctx->dd.config[AUTHENTICATION_DOMAIN]);
    conn->dom_ctx = &(conn->phys_ctx->dd);
  }
  mg_lock_context(conn->phys_ctx);
  SSL_set_SSL_CTX(ssl, conn->dom_ctx->ssl_ctx);
  mg_unlock_context(conn->phys_ctx);
  return SSL_TLSEXT_ERR_OK;
}


#if defined(USE_ALPN)
static const char alpn_proto_list[] = "\x02h2\x08http/1.1\x08http/1.0";
static const char *alpn_proto_order_http1[] = {alpn_proto_list + 3,
                                               alpn_proto_list + 3 + 8,
                                               NULL};
#if defined(USE_HTTP2)
static const char *alpn_proto_order_http2[] = {alpn_proto_list,
                                               alpn_proto_list + 3,
                                               alpn_proto_list + 3 + 8,
                                               NULL};
#endif

static int
alpn_select_cb(SSL *ssl,
               const unsigned char **out,
               unsigned char *outlen,
               const unsigned char *in,
               unsigned int inlen,
               void *arg)
{
  struct mg_domain_context *dom_ctx = (struct mg_domain_context *)arg;
  unsigned int i, j, enable_http2 = 0;
  const char **alpn_proto_order = alpn_proto_order_http1;

  struct mg_workerTLS *tls =
      (struct mg_workerTLS *)pthread_getspecific(sTlsKey);

  (void)ssl;

  if (tls == NULL) {
    /* Need to store protocol in Thread Local Storage */
    /* If there is no Thread Local Storage, don't use ALPN */
    return SSL_TLSEXT_ERR_NOACK;
  }

#if defined(USE_HTTP2)
  enable_http2 = (0 == strcmp(dom_ctx->config[ENABLE_HTTP2], "yes"));
  if (enable_http2) {
    alpn_proto_order = alpn_proto_order_http2;
  }
#endif

  for (j = 0; alpn_proto_order[j] != NULL; j++) {
    /* check all accepted protocols in this order */
    const char *alpn_proto = alpn_proto_order[j];
    /* search input for matching protocol */
    for (i = 0; i < inlen; i++) {
      if (!memcmp(in + i, alpn_proto, (unsigned char)alpn_proto[0])) {
        *out = in + i + 1;
        *outlen = in[i];
        tls->alpn_proto = alpn_proto;
        return SSL_TLSEXT_ERR_OK;
      }
    }
  }

  /* Nothing found */
  return SSL_TLSEXT_ERR_NOACK;
}


static int
next_protos_advertised_cb(SSL *ssl,
                          const unsigned char **data,
                          unsigned int *len,
                          void *arg)
{
  struct mg_domain_context *dom_ctx = (struct mg_domain_context *)arg;
  *data = (const unsigned char *)alpn_proto_list;
  *len = (unsigned int)strlen((const char *)data);

  (void)ssl;
  (void)dom_ctx;

  return SSL_TLSEXT_ERR_OK;
}


static int
init_alpn(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
  unsigned int alpn_len = (unsigned int)strlen((char *)alpn_proto_list);
  int ret = SSL_CTX_set_alpn_protos(dom_ctx->ssl_ctx,
                                    (const unsigned char *)alpn_proto_list,
                                    alpn_len);
  if (ret != 0) {
    mg_cry_ctx_internal(phys_ctx,
                        "SSL_CTX_set_alpn_protos error: %s",
                        ssl_error());
  }

  SSL_CTX_set_alpn_select_cb(dom_ctx->ssl_ctx,
                             alpn_select_cb,
                             (void *)dom_ctx);

  SSL_CTX_set_next_protos_advertised_cb(dom_ctx->ssl_ctx,
                                        next_protos_advertised_cb,
                                        (void *)dom_ctx);

  return ret;
}
#endif


/* Setup SSL CTX as required by CivetWeb */
static int
init_ssl_ctx_impl(struct mg_context *phys_ctx,
                  struct mg_domain_context *dom_ctx,
                  const char *pem,
                  const char *chain)
{
  int callback_ret;
  int should_verify_peer;
  int peer_certificate_optional;
  const char *ca_path;
  const char *ca_file;
  int use_default_verify_paths;
  int verify_depth;
  struct timespec now_mt;
  md5_byte_t ssl_context_id[16];
  md5_state_t md5state;
  int protocol_ver;
  int ssl_cache_timeout;

#if (defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0))                     \
    && !defined(NO_SSL_DL)
  if ((dom_ctx->ssl_ctx = SSL_CTX_new(TLS_server_method())) == NULL) {
    mg_cry_ctx_internal(phys_ctx,
                        "SSL_CTX_new (server) error: %s",
                        ssl_error());
    return 0;
  }
#else
  if ((dom_ctx->ssl_ctx = SSL_CTX_new(SSLv23_server_method())) == NULL) {
    mg_cry_ctx_internal(phys_ctx,
                        "SSL_CTX_new (server) error: %s",
                        ssl_error());
    return 0;
  }
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */

#if defined(SSL_OP_NO_TLSv1_3)
  SSL_CTX_clear_options(dom_ctx->ssl_ctx,
                        SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1
                            | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1_2
                            | SSL_OP_NO_TLSv1_3);
#else
  SSL_CTX_clear_options(dom_ctx->ssl_ctx,
                        SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1
                            | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1_2);
#endif

  protocol_ver = atoi(dom_ctx->config[SSL_PROTOCOL_VERSION]);
  SSL_CTX_set_options(dom_ctx->ssl_ctx, ssl_get_protocol(protocol_ver));
  SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_SINGLE_DH_USE);
  SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
  SSL_CTX_set_options(dom_ctx->ssl_ctx,
                      SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
  SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_NO_COMPRESSION);

#if defined(SSL_OP_NO_RENEGOTIATION)
  SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_NO_RENEGOTIATION);
#endif

#if !defined(NO_SSL_DL)
  SSL_CTX_set_ecdh_auto(dom_ctx->ssl_ctx, 1);
#endif /* NO_SSL_DL */

  /* In SSL documentation examples callback defined without const
   * specifier 'void (*)(SSL *, int, int)'   See:
   * https://www.openssl.org/docs/man1.0.2/ssl/ssl.html
   * https://www.openssl.org/docs/man1.1.0/ssl/ssl.html
   * But in the source code const SSL is used:
   * 'void (*)(const SSL *, int, int)' See:
   * https://github.com/openssl/openssl/blob/1d97c8435171a7af575f73c526d79e1ef0ee5960/ssl/ssl.h#L1173
   * Problem about wrong documentation described, but not resolved:
   * https://bugs.launchpad.net/ubuntu/+source/openssl/+bug/1147526
   * Wrong const cast ignored on C or can be suppressed by compiler flags.
   * But when compiled with modern C++ compiler, correct const should be
   * provided
   */
  SSL_CTX_set_info_callback(dom_ctx->ssl_ctx, ssl_info_callback);

  SSL_CTX_set_tlsext_servername_callback(dom_ctx->ssl_ctx,
                                         ssl_servername_callback);

  /* If a callback has been specified, call it. */
  callback_ret = (phys_ctx->callbacks.init_ssl == NULL)
                     ? 0
                     : (phys_ctx->callbacks.init_ssl(dom_ctx->ssl_ctx,
                                                     phys_ctx->user_data));

  /* If callback returns 0, civetweb sets up the SSL certificate.
   * If it returns 1, civetweb assumes the callback already did this.
   * If it returns -1, initializing ssl fails. */
  if (callback_ret < 0) {
    mg_cry_ctx_internal(phys_ctx,
                        "SSL callback returned error: %i",
                        callback_ret);
    return 0;
  }
  if (callback_ret > 0) {
    /* Callback did everything. */
    return 1;
  }

  /* If a domain callback has been specified, call it. */
  callback_ret = (phys_ctx->callbacks.init_ssl_domain == NULL)
                     ? 0
                     : (phys_ctx->callbacks.init_ssl_domain(
                           dom_ctx->config[AUTHENTICATION_DOMAIN],
                           dom_ctx->ssl_ctx,
                           phys_ctx->user_data));

  /* If domain callback returns 0, civetweb sets up the SSL certificate.
   * If it returns 1, civetweb assumes the callback already did this.
   * If it returns -1, initializing ssl fails. */
  if (callback_ret < 0) {
    mg_cry_ctx_internal(phys_ctx,
                        "Domain SSL callback returned error: %i",
                        callback_ret);
    return 0;
  }
  if (callback_ret > 0) {
    /* Domain callback did everything. */
    return 1;
  }

  /* Use some combination of start time, domain and port as a SSL
   * context ID. This should be unique on the current machine. */
  md5_init(&md5state);
  clock_gettime(CLOCK_MONOTONIC, &now_mt);
  md5_append(&md5state, (const md5_byte_t *)&now_mt, sizeof(now_mt));
  md5_append(&md5state,
             (const md5_byte_t *)phys_ctx->dd.config[LISTENING_PORTS],
             strlen(phys_ctx->dd.config[LISTENING_PORTS]));
  md5_append(&md5state,
             (const md5_byte_t *)dom_ctx->config[AUTHENTICATION_DOMAIN],
             strlen(dom_ctx->config[AUTHENTICATION_DOMAIN]));
  md5_append(&md5state, (const md5_byte_t *)phys_ctx, sizeof(*phys_ctx));
  md5_append(&md5state, (const md5_byte_t *)dom_ctx, sizeof(*dom_ctx));
  md5_finish(&md5state, ssl_context_id);

  SSL_CTX_set_session_id_context(dom_ctx->ssl_ctx,
                                 (unsigned char *)ssl_context_id,
                                 sizeof(ssl_context_id));

  if (pem != NULL) {
    if (!ssl_use_pem_file(phys_ctx, dom_ctx, pem, chain)) {
      return 0;
    }
  }

  /* Should we support client certificates? */
  /* Default is "no". */
  should_verify_peer = 0;
  peer_certificate_optional = 0;
  if (dom_ctx->config[SSL_DO_VERIFY_PEER] != NULL) {
    if (mg_strcasecmp(dom_ctx->config[SSL_DO_VERIFY_PEER], "yes") == 0) {
      /* Yes, they are mandatory */
      should_verify_peer = 1;
    } else if (mg_strcasecmp(dom_ctx->config[SSL_DO_VERIFY_PEER],
                             "optional")
               == 0) {
      /* Yes, they are optional */
      should_verify_peer = 1;
      peer_certificate_optional = 1;
    }
  }

  use_default_verify_paths =
      (dom_ctx->config[SSL_DEFAULT_VERIFY_PATHS] != NULL)
      && (mg_strcasecmp(dom_ctx->config[SSL_DEFAULT_VERIFY_PATHS], "yes")
          == 0);

  if (should_verify_peer) {
    ca_path = dom_ctx->config[SSL_CA_PATH];
    ca_file = dom_ctx->config[SSL_CA_FILE];
    if (SSL_CTX_load_verify_locations(dom_ctx->ssl_ctx, ca_file, ca_path)
        != 1) {
      mg_cry_ctx_internal(phys_ctx,
                          "SSL_CTX_load_verify_locations error: %s "
                          "ssl_verify_peer requires setting "
                          "either ssl_ca_path or ssl_ca_file. "
                          "Is any of them present in the "
                          ".conf file?",
                          ssl_error());
      return 0;
    }

    if (peer_certificate_optional) {
      SSL_CTX_set_verify(dom_ctx->ssl_ctx, SSL_VERIFY_PEER, NULL);
    } else {
      SSL_CTX_set_verify(dom_ctx->ssl_ctx,
                         SSL_VERIFY_PEER
                             | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                         NULL);
    }

    if (use_default_verify_paths
        && (SSL_CTX_set_default_verify_paths(dom_ctx->ssl_ctx) != 1)) {
      mg_cry_ctx_internal(phys_ctx,
                          "SSL_CTX_set_default_verify_paths error: %s",
                          ssl_error());
      return 0;
    }

    if (dom_ctx->config[SSL_VERIFY_DEPTH]) {
      verify_depth = atoi(dom_ctx->config[SSL_VERIFY_DEPTH]);
      SSL_CTX_set_verify_depth(dom_ctx->ssl_ctx, verify_depth);
    }
  }

  if (dom_ctx->config[SSL_CIPHER_LIST] != NULL) {
    if (SSL_CTX_set_cipher_list(dom_ctx->ssl_ctx,
                                dom_ctx->config[SSL_CIPHER_LIST])
        != 1) {
      mg_cry_ctx_internal(phys_ctx,
                          "SSL_CTX_set_cipher_list error: %s",
                          ssl_error());
    }
  }

  /* SSL session caching */
  ssl_cache_timeout = ((dom_ctx->config[SSL_CACHE_TIMEOUT] != NULL)
                           ? atoi(dom_ctx->config[SSL_CACHE_TIMEOUT])
                           : 0);
  if (ssl_cache_timeout > 0) {
    SSL_CTX_set_session_cache_mode(dom_ctx->ssl_ctx, SSL_SESS_CACHE_BOTH);
    /* SSL_CTX_sess_set_cache_size(dom_ctx->ssl_ctx, 10000);  ... use
     * default */
    SSL_CTX_set_timeout(dom_ctx->ssl_ctx, (long)ssl_cache_timeout);
  }

#if defined(USE_ALPN)
  /* Initialize ALPN only of TLS library (OpenSSL version) supports ALPN */
#if !defined(NO_SSL_DL)
  if (!tls_feature_missing[TLS_ALPN])
#endif
  {
    init_alpn(phys_ctx, dom_ctx);
  }
#endif

  return 1;
}


/* Check if SSL is required.
 * If so, dynamically load SSL library
 * and set up ctx->ssl_ctx pointer. */
static int
init_ssl_ctx(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
  void *ssl_ctx = 0;
  int callback_ret;
  const char *pem;
  const char *chain;
  char ebuf[128];

  if (!phys_ctx) {
    return 0;
  }

  if (!dom_ctx) {
    dom_ctx = &(phys_ctx->dd);
  }

  if (!is_ssl_port_used(dom_ctx->config[LISTENING_PORTS])) {
    /* No SSL port is set. No need to setup SSL. */
    return 1;
  }

  /* Check for external SSL_CTX */
  callback_ret =
      (phys_ctx->callbacks.external_ssl_ctx == NULL)
          ? 0
          : (phys_ctx->callbacks.external_ssl_ctx(&ssl_ctx,
                                                  phys_ctx->user_data));

  if (callback_ret < 0) {
    /* Callback exists and returns <0: Initializing failed. */
    mg_cry_ctx_internal(phys_ctx,
                        "external_ssl_ctx callback returned error: %i",
                        callback_ret);
    return 0;
  } else if (callback_ret > 0) {
    /* Callback exists and returns >0: Initializing complete,
     * civetweb should not modify the SSL context. */
    dom_ctx->ssl_ctx = (SSL_CTX *)ssl_ctx;
    if (!initialize_openssl(ebuf, sizeof(ebuf))) {
      mg_cry_ctx_internal(phys_ctx, "%s", ebuf);
      return 0;
    }
    return 1;
  }
  /* If the callback does not exist or return 0, civetweb must initialize
   * the SSL context. Handle "domain" callback next. */

  /* Check for external domain SSL_CTX callback. */
  callback_ret = (phys_ctx->callbacks.external_ssl_ctx_domain == NULL)
                     ? 0
                     : (phys_ctx->callbacks.external_ssl_ctx_domain(
                           dom_ctx->config[AUTHENTICATION_DOMAIN],
                           &ssl_ctx,
                           phys_ctx->user_data));

  if (callback_ret < 0) {
    /* Callback < 0: Error. Abort init. */
    mg_cry_ctx_internal(
        phys_ctx,
        "external_ssl_ctx_domain callback returned error: %i",
        callback_ret);
    return 0;
  } else if (callback_ret > 0) {
    /* Callback > 0: Consider init done. */
    dom_ctx->ssl_ctx = (SSL_CTX *)ssl_ctx;
    if (!initialize_openssl(ebuf, sizeof(ebuf))) {
      mg_cry_ctx_internal(phys_ctx, "%s", ebuf);
      return 0;
    }
    return 1;
  }
  /* else: external_ssl_ctx/external_ssl_ctx_domain do not exist or return
   * 0, CivetWeb should continue initializing SSL */

  /* If PEM file is not specified and the init_ssl callbacks
   * are not specified, setup will fail. */
  if (((pem = dom_ctx->config[SSL_CERTIFICATE]) == NULL)
      && (phys_ctx->callbacks.init_ssl == NULL)
      && (phys_ctx->callbacks.init_ssl_domain == NULL)) {
    /* No certificate and no init_ssl callbacks:
     * Essential data to set up TLS is missing.
     */
    mg_cry_ctx_internal(phys_ctx,
                        "Initializing SSL failed: -%s is not set",
                        config_options[SSL_CERTIFICATE].name);
    return 0;
  }

  /* If a certificate chain is configured, use it. */
  chain = dom_ctx->config[SSL_CERTIFICATE_CHAIN];
  if (chain == NULL) {
    /* Default: certificate chain in PEM file */
    chain = pem;
  }
  if ((chain != NULL) && (*chain == 0)) {
    /* If the chain is an empty string, don't use it. */
    chain = NULL;
  }

  if (!initialize_openssl(ebuf, sizeof(ebuf))) {
    mg_cry_ctx_internal(phys_ctx, "%s", ebuf);
    return 0;
  }

  return init_ssl_ctx_impl(phys_ctx, dom_ctx, pem, chain);
}


static void
uninitialize_openssl(void)
{
#if defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0)

  if (mg_atomic_dec(&cryptolib_users) == 0) {

    /* Shutdown according to
     * https://wiki.openssl.org/index.php/Library_Initialization#Cleanup
     * http://stackoverflow.com/questions/29845527/how-to-properly-uninitialize-openssl
     */
    CONF_modules_unload(1);
#else
  int i;

  if (mg_atomic_dec(&cryptolib_users) == 0) {

    /* Shutdown according to
     * https://wiki.openssl.org/index.php/Library_Initialization#Cleanup
     * http://stackoverflow.com/questions/29845527/how-to-properly-uninitialize-openssl
     */
    CRYPTO_set_locking_callback(NULL);
    CRYPTO_set_id_callback(NULL);
    ENGINE_cleanup();
    CONF_modules_unload(1);
    ERR_free_strings();
    EVP_cleanup();
    CRYPTO_cleanup_all_ex_data();
    OPENSSL_REMOVE_THREAD_STATE();

    for (i = 0; i < CRYPTO_num_locks(); i++) {
      pthread_mutex_destroy(&ssl_mutexes[i]);
    }
    mg_free(ssl_mutexes);
    ssl_mutexes = NULL;
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */
  }
}
#endif /* !defined(NO_SSL) && !defined(USE_MBEDTLS) */


#if !defined(NO_FILESYSTEMS)
static int
set_gpass_option(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
  if (phys_ctx) {
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    const char *path;
    struct mg_connection fc;
    if (!dom_ctx) {
      dom_ctx = &(phys_ctx->dd);
    }
    path = dom_ctx->config[GLOBAL_PASSWORDS_FILE];
    if ((path != NULL)
        && !mg_stat(fake_connection(&fc, phys_ctx), path, &file.stat)) {
      mg_cry_ctx_internal(phys_ctx,
                          "Cannot open %s: %s",
                          path,
                          strerror(ERRNO));
      return 0;
    }
    return 1;
  }
  return 0;
}
#endif /* NO_FILESYSTEMS */


static int
set_acl_option(struct mg_context *phys_ctx)
{
  union usa sa;
  memset(&sa, 0, sizeof(sa));
#if defined(USE_IPV6)
  sa.sin6.sin6_family = AF_INET6;
#else
  sa.sin.sin_family = AF_INET;
#endif
  return check_acl(phys_ctx, &sa) != -1;
}


static void
reset_per_request_attributes(struct mg_connection *conn)
{
  if (!conn) {
    return;
  }

  conn->num_bytes_sent = conn->consumed_content = 0;

  conn->path_info = NULL;
  conn->status_code = -1;
  conn->content_len = -1;
  conn->is_chunked = 0;
  conn->must_close = 0;
  conn->request_len = 0;
  conn->request_state = 0;
  conn->throttle = 0;
  conn->accept_gzip = 0;

  conn->response_info.content_length = conn->request_info.content_length = -1;
  conn->response_info.http_version = conn->request_info.http_version = NULL;
  conn->response_info.num_headers = conn->request_info.num_headers = 0;
  conn->response_info.status_text = NULL;
  conn->response_info.status_code = 0;

  conn->request_info.remote_user = NULL;
  conn->request_info.request_method = NULL;
  conn->request_info.request_uri = NULL;

  /* Free cleaned local URI (if any) */
  if (conn->request_info.local_uri != conn->request_info.local_uri_raw) {
    mg_free((void *)conn->request_info.local_uri);
    conn->request_info.local_uri = NULL;
  }
  conn->request_info.local_uri = NULL;

#if defined(USE_SERVER_STATS)
  conn->processing_time = 0;
#endif
}


static int
set_tcp_nodelay(const struct socket *so, int nodelay_on)
{
  if ((so->lsa.sa.sa_family == AF_INET)
      || (so->lsa.sa.sa_family == AF_INET6)) {
    /* Only for TCP sockets */
    if (setsockopt(so->sock,
                   IPPROTO_TCP,
                   TCP_NODELAY,
                   (SOCK_OPT_TYPE)&nodelay_on,
                   sizeof(nodelay_on))
        != 0) {
      /* Error */
      return 1;
    }
  }
  /* OK */
  return 0;
}


#if !defined(__ZEPHYR__)
static void
close_socket_gracefully(struct mg_connection *conn)
{
#if defined(_WIN32)
  char buf[MG_BUF_LEN];
  int n;
#endif
  struct linger linger;
  int error_code = 0;
  int linger_timeout = -2;
  socklen_t opt_len = sizeof(error_code);

  if (!conn) {
    return;
  }

  /* http://msdn.microsoft.com/en-us/library/ms739165(v=vs.85).aspx:
   * "Note that enabling a nonzero timeout on a nonblocking socket
   * is not recommended.", so set it to blocking now */
  set_blocking_mode(conn->client.sock);

  /* Send FIN to the client */
  shutdown(conn->client.sock, SHUTDOWN_WR);

#if defined(_WIN32)
  /* Read and discard pending incoming data. If we do not do that and
   * close
   * the socket, the data in the send buffer may be discarded. This
   * behaviour is seen on Windows, when client keeps sending data
   * when server decides to close the connection; then when client
   * does recv() it gets no data back. */
  do {
    n = pull_inner(NULL, conn, buf, sizeof(buf), /* Timeout in s: */ 1.0);
  } while (n > 0);
#endif

  if (conn->dom_ctx->config[LINGER_TIMEOUT]) {
    linger_timeout = atoi(conn->dom_ctx->config[LINGER_TIMEOUT]);
  }

  /* Set linger option according to configuration */
  if (linger_timeout >= 0) {
    /* Set linger option to avoid socket hanging out after close. This
     * prevent ephemeral port exhaust problem under high QPS. */
    linger.l_onoff = 1;

#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable : 4244)
#endif
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wconversion"
#endif
    /* Data type of linger structure elements may differ,
     * so we don't know what cast we need here.
     * Disable type conversion warnings. */

    linger.l_linger = (linger_timeout + 999) / 1000;

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif
#if defined(_MSC_VER)
#pragma warning(pop)
#endif

  } else {
    linger.l_onoff = 0;
    linger.l_linger = 0;
  }

  if (linger_timeout < -1) {
    /* Default: don't configure any linger */
  } else if (getsockopt(conn->client.sock,
                        SOL_SOCKET,
                        SO_ERROR,
#if defined(_WIN32) /* WinSock uses different data type here */
                        (char *)&error_code,
#else
                        &error_code,
#endif
                        &opt_len)
             != 0) {
    /* Cannot determine if socket is already closed. This should
     * not occur and never did in a test. Log an error message
     * and continue. */
    mg_cry_internal(conn,
                    "%s: getsockopt(SOL_SOCKET SO_ERROR) failed: %s",
                    __func__,
                    strerror(ERRNO));
#if defined(_WIN32)
  } else if (error_code == WSAECONNRESET) {
#else
  } else if (error_code == ECONNRESET) {
#endif
    /* Socket already closed by client/peer, close socket without linger
     */
  } else {

    /* Set linger timeout */
    if (setsockopt(conn->client.sock,
                   SOL_SOCKET,
                   SO_LINGER,
                   (char *)&linger,
                   sizeof(linger))
        != 0) {
      mg_cry_internal(
          conn,
          "%s: setsockopt(SOL_SOCKET SO_LINGER(%i,%i)) failed: %s",
          __func__,
          linger.l_onoff,
          linger.l_linger,
          strerror(ERRNO));
    }
  }

  /* Now we know that our FIN is ACK-ed, safe to close */
  closesocket(conn->client.sock);
  conn->client.sock = INVALID_SOCKET;
}
#endif


static void
close_connection(struct mg_connection *conn)
{
#if defined(USE_SERVER_STATS)
  conn->conn_state = 6; /* to close */
#endif

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  if (conn->lua_websocket_state) {
    lua_websocket_close(conn, conn->lua_websocket_state);
    conn->lua_websocket_state = NULL;
  }
#endif

  mg_lock_connection(conn);

  /* Set close flag, so keep-alive loops will stop */
  conn->must_close = 1;

  /* call the connection_close callback if assigned */
  if (conn->phys_ctx->callbacks.connection_close != NULL) {
    if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
      conn->phys_ctx->callbacks.connection_close(conn);
    }
  }

  /* Reset user data, after close callback is called.
   * Do not reuse it. If the user needs a destructor,
   * it must be done in the connection_close callback. */
  mg_set_user_connection_data(conn, NULL);

#if defined(USE_SERVER_STATS)
  conn->conn_state = 7; /* closing */
#endif

#if defined(USE_MBEDTLS)
  if (conn->ssl != NULL) {
    mbed_ssl_close(conn->ssl);
    conn->ssl = NULL;
  }
#elif !defined(NO_SSL)
  if (conn->ssl != NULL) {
    /* Run SSL_shutdown twice to ensure completely close SSL connection
     */
    SSL_shutdown(conn->ssl);
    SSL_free(conn->ssl);
    OPENSSL_REMOVE_THREAD_STATE();
    conn->ssl = NULL;
  }
#endif
  if (conn->client.sock != INVALID_SOCKET) {
#if defined(__ZEPHYR__)
    closesocket(conn->client.sock);
#else
    close_socket_gracefully(conn);
#endif
    conn->client.sock = INVALID_SOCKET;
  }

  /* call the connection_closed callback if assigned */
  if (conn->phys_ctx->callbacks.connection_closed != NULL) {
    if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
      conn->phys_ctx->callbacks.connection_closed(conn);
    }
  }

  mg_unlock_connection(conn);

#if defined(USE_SERVER_STATS)
  conn->conn_state = 8; /* closed */
#endif
}


CIVETWEB_API void
mg_close_connection(struct mg_connection *conn)
{
  if ((conn == NULL) || (conn->phys_ctx == NULL)) {
    return;
  }

#if defined(USE_WEBSOCKET)
  if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
    if (conn->in_websocket_handling) {
      /* Set close flag, so the server thread can exit. */
      conn->must_close = 1;
      return;
    }
  }
  if (conn->phys_ctx->context_type == CONTEXT_WS_CLIENT) {

    unsigned int i;

    /* client context: loops must end */
    STOP_FLAG_ASSIGN(&conn->phys_ctx->stop_flag, 1);
    conn->must_close = 1;

    /* We need to get the client thread out of the select/recv call
     * here. */
    /* Since we use a sleep quantum of some seconds to check for recv
     * timeouts, we will just wait a few seconds in mg_join_thread. */

    /* join worker thread */
    for (i = 0; i < conn->phys_ctx->cfg_worker_threads; i++) {
      mg_join_thread(conn->phys_ctx->worker_threadids[i]);
    }
  }
#endif /* defined(USE_WEBSOCKET) */

  close_connection(conn);

#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
  if (((conn->phys_ctx->context_type == CONTEXT_HTTP_CLIENT)
       || (conn->phys_ctx->context_type == CONTEXT_WS_CLIENT))
      && (conn->phys_ctx->dd.ssl_ctx != NULL)) {
    SSL_CTX_free(conn->phys_ctx->dd.ssl_ctx);
  }
#endif

#if defined(USE_WEBSOCKET)
  if (conn->phys_ctx->context_type == CONTEXT_WS_CLIENT) {
    mg_free(conn->phys_ctx->worker_threadids);
    (void)pthread_mutex_destroy(&conn->mutex);
    mg_free(conn);
  } else if (conn->phys_ctx->context_type == CONTEXT_HTTP_CLIENT) {
    (void)pthread_mutex_destroy(&conn->mutex);
    mg_free(conn);
  }
#else
  if (conn->phys_ctx->context_type == CONTEXT_HTTP_CLIENT) { /* Client */
    (void)pthread_mutex_destroy(&conn->mutex);
    mg_free(conn);
  }
#endif /* defined(USE_WEBSOCKET) */
}


static struct mg_connection *
mg_connect_client_impl(const struct mg_client_options *client_options,
                       int use_ssl,
                       struct mg_init_data *init,
                       struct mg_error_data *error)
{
  struct mg_connection *conn = NULL;
  SOCKET sock;
  union usa sa;
  struct sockaddr *psa;
  socklen_t len;

  unsigned max_req_size =
      (unsigned)atoi(config_options[MAX_REQUEST_SIZE].default_value);

  /* Size of structures, aligned to 8 bytes */
  size_t conn_size = ((sizeof(struct mg_connection) + 7) >> 3) << 3;
  size_t ctx_size = ((sizeof(struct mg_context) + 7) >> 3) << 3;
  size_t alloc_size = conn_size + ctx_size + max_req_size;

  (void)init; /* TODO: Implement required options */

  conn = (struct mg_connection *)mg_calloc(1, alloc_size);

  if (error != NULL) {
    error->code = MG_ERROR_DATA_CODE_OK;
    error->code_sub = 0;
    if (error->text_buffer_size > 0) {
      error->text[0] = 0;
    }
  }

  if (conn == NULL) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)alloc_size;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "calloc(): %s",
                  strerror(ERRNO));
    }
    return NULL;
  }

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
#endif /* defined(GCC_DIAGNOSTIC) */
  /* conn_size is aligned to 8 bytes */

  conn->phys_ctx = (struct mg_context *)(((char *)conn) + conn_size);

#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */

  conn->buf = (((char *)conn) + conn_size + ctx_size);
  conn->buf_size = (int)max_req_size;
  conn->phys_ctx->context_type = CONTEXT_HTTP_CLIENT;
  conn->dom_ctx = &(conn->phys_ctx->dd);

  if (!connect_socket(conn->phys_ctx,
                      client_options->host,
                      client_options->port,
                      use_ssl,
                      error,
                      &sock,
                      &sa)) {
    /* "error" will be set by connect_socket. */
    /* free all memory and return NULL; */
    mg_free(conn);
    return NULL;
  }

#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
#if (defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0))                     \
    && !defined(NO_SSL_DL)

  if (use_ssl
      && (conn->dom_ctx->ssl_ctx = SSL_CTX_new(TLS_client_method()))
             == NULL) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "SSL_CTX_new error: %s",
                  ssl_error());
    }

    closesocket(sock);
    mg_free(conn);
    return NULL;
  }

#else

  if (use_ssl
      && (conn->dom_ctx->ssl_ctx = SSL_CTX_new(SSLv23_client_method()))
             == NULL) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "SSL_CTX_new error: %s",
                  ssl_error());
    }

    closesocket(sock);
    mg_free(conn);
    return NULL;
  }

#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */
#endif /* NO_SSL */

#if defined(USE_IPV6)
  len = (sa.sa.sa_family == AF_INET) ? sizeof(conn->client.rsa.sin)
                                     : sizeof(conn->client.rsa.sin6);
  psa = (sa.sa.sa_family == AF_INET)
            ? (struct sockaddr *)&(conn->client.rsa.sin)
            : (struct sockaddr *)&(conn->client.rsa.sin6);
#else
  len = sizeof(conn->client.rsa.sin);
  psa = (struct sockaddr *)&(conn->client.rsa.sin);
#endif

  conn->client.sock = sock;
  conn->client.lsa = sa;

  if (getsockname(sock, psa, &len) != 0) {
    mg_cry_internal(conn,
                    "%s: getsockname() failed: %s",
                    __func__,
                    strerror(ERRNO));
  }

  conn->client.is_ssl = use_ssl ? 1 : 0;
  if (0 != pthread_mutex_init(&conn->mutex, &pthread_mutex_attr)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OS_ERROR;
      error->code_sub = (unsigned)ERRNO;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for ebuf */
                  error->text,
                  error->text_buffer_size,
                  "Can not create mutex");
    }
#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
    SSL_CTX_free(conn->dom_ctx->ssl_ctx);
#endif
    closesocket(sock);
    mg_free(conn);
    return NULL;
  }

#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
  if (use_ssl) {
    /* TODO: Check ssl_verify_peer and ssl_ca_path here.
     * SSL_CTX_set_verify call is needed to switch off server
     * certificate checking, which is off by default in OpenSSL and
     * on in yaSSL. */
    /* TODO: SSL_CTX_set_verify(conn->dom_ctx,
     * SSL_VERIFY_PEER, verify_ssl_server); */

    if (client_options->client_cert) {
      if (!ssl_use_pem_file(conn->phys_ctx,
                            conn->dom_ctx,
                            client_options->client_cert,
                            NULL)) {
        if (error != NULL) {
          error->code = MG_ERROR_DATA_CODE_TLS_CLIENT_CERT_ERROR;
          mg_snprintf(NULL,
                      NULL, /* No truncation check for ebuf */
                      error->text,
                      error->text_buffer_size,
                      "Can not use SSL client certificate");
        }

        SSL_CTX_free(conn->dom_ctx->ssl_ctx);
        closesocket(sock);
        mg_free(conn);
        return NULL;
      }
    }

    if (client_options->server_cert) {
      if (SSL_CTX_load_verify_locations(conn->dom_ctx->ssl_ctx,
                                        client_options->server_cert,
                                        NULL)
          != 1) {
        if (error != NULL) {
          error->code = MG_ERROR_DATA_CODE_TLS_SERVER_CERT_ERROR;
          mg_snprintf(NULL,
                      NULL, /* No truncation check for ebuf */
                      error->text,
                      error->text_buffer_size,
                      "SSL_CTX_load_verify_locations error: %s",
                      ssl_error());
        }
        SSL_CTX_free(conn->dom_ctx->ssl_ctx);
        closesocket(sock);
        mg_free(conn);
        return NULL;
      }
      SSL_CTX_set_verify(conn->dom_ctx->ssl_ctx, SSL_VERIFY_PEER, NULL);
    } else {
      SSL_CTX_set_verify(conn->dom_ctx->ssl_ctx, SSL_VERIFY_NONE, NULL);
    }

    if (!sslize(conn, SSL_connect, client_options)) {
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_TLS_CONNECT_ERROR;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for ebuf */
                    error->text,
                    error->text_buffer_size,
                    "SSL connection error");
      }
      SSL_CTX_free(conn->dom_ctx->ssl_ctx);
      closesocket(sock);
      mg_free(conn);
      return NULL;
    }
  }
#endif

  return conn;
}


CIVETWEB_API struct mg_connection *
mg_connect_client_secure(const struct mg_client_options *client_options,
                         char *error_buffer,
                         size_t error_buffer_size)
{
  struct mg_init_data init;
  struct mg_error_data error;

  memset(&init, 0, sizeof(init));
  memset(&error, 0, sizeof(error));
  error.text_buffer_size = error_buffer_size;
  error.text = error_buffer;
  return mg_connect_client_impl(client_options, 1, &init, &error);
}


CIVETWEB_API struct mg_connection *
mg_connect_client(const char *host,
                  int port,
                  int use_ssl,
                  char *error_buffer,
                  size_t error_buffer_size)
{
  struct mg_client_options opts;
  struct mg_init_data init;
  struct mg_error_data error;

  memset(&init, 0, sizeof(init));

  memset(&error, 0, sizeof(error));
  error.text_buffer_size = error_buffer_size;
  error.text = error_buffer;

  memset(&opts, 0, sizeof(opts));
  opts.host = host;
  opts.port = port;
  if (use_ssl) {
    opts.host_name = host;
  }

  return mg_connect_client_impl(&opts, use_ssl, &init, &error);
}


#if defined(MG_EXPERIMENTAL_INTERFACES)
CIVETWEB_API struct mg_connection *
mg_connect_client2(const char *host,
                   const char *protocol,
                   int port,
                   const char *path,
                   struct mg_init_data *init,
                   struct mg_error_data *error)
{
  (void)path;

  int is_ssl, is_ws;
  /* void *user_data = (init != NULL) ? init->user_data : NULL; -- TODO */

  if (error != NULL) {
    error->code = MG_ERROR_DATA_CODE_OK;
    error->code_sub = 0;
    if (error->text_buffer_size > 0) {
      *error->text = 0;
    }
  }

  if ((host == NULL) || (protocol == NULL)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Invalid parameters");
    }
    return NULL;
  }

  /* check all known protocols */
  if (!mg_strcasecmp(protocol, "http")) {
    is_ssl = 0;
    is_ws = 0;
  } else if (!mg_strcasecmp(protocol, "https")) {
    is_ssl = 1;
    is_ws = 0;
#if defined(USE_WEBSOCKET)
  } else if (!mg_strcasecmp(protocol, "ws")) {
    is_ssl = 0;
    is_ws = 1;
  } else if (!mg_strcasecmp(protocol, "wss")) {
    is_ssl = 1;
    is_ws = 1;
#endif
  } else {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Protocol %s not supported",
                  protocol);
    }
    return NULL;
  }

  /* TODO: The current implementation here just calls the old
   * implementations, without using any new options. This is just a first
   * step to test the new interfaces. */
#if defined(USE_WEBSOCKET)
  if (is_ws) {
    /* TODO: implement all options */
    return mg_connect_websocket_client(
        host,
        port,
        is_ssl,
        ((error != NULL) ? error->text : NULL),
        ((error != NULL) ? error->text_buffer_size : 0),
        (path ? path : ""),
        NULL /* TODO: origin */,
        experimental_websocket_client_data_wrapper,
        experimental_websocket_client_close_wrapper,
        (void *)init->callbacks);
  }
#else
  (void)is_ws;
#endif

  /* TODO: all additional options */
  struct mg_client_options opts;

  memset(&opts, 0, sizeof(opts));
  opts.host = host;
  opts.port = port;

  return mg_connect_client_impl(&opts, is_ssl, init, error);
}
#endif


static const struct {
  const char *proto;
  size_t proto_len;
  unsigned default_port;
} abs_uri_protocols[] = {{"http://", 7, 80},
                         {"https://", 8, 443},
                         {"ws://", 5, 80},
                         {"wss://", 6, 443},
                         {NULL, 0, 0}};


/* Check if the uri is valid.
 * return 0 for invalid uri,
 * return 1 for *,
 * return 2 for relative uri,
 * return 3 for absolute uri without port,
 * return 4 for absolute uri with port */
static int
get_uri_type(const char *uri)
{
  int i;
  const char *hostend, *portbegin;
  char *portend;
  unsigned long port;

  /* According to the HTTP standard
   * http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2
   * URI can be an asterisk (*) or should start with slash (relative uri),
   * or it should start with the protocol (absolute uri). */
  if ((uri[0] == '*') && (uri[1] == '\0')) {
    /* asterisk */
    return 1;
  }

  /* Valid URIs according to RFC 3986
   * (https://www.ietf.org/rfc/rfc3986.txt)
   * must only contain reserved characters :/?#[]@!$&'()*+,;=
   * and unreserved characters A-Z a-z 0-9 and -._~
   * and % encoded symbols.
   */
  for (i = 0; uri[i] != 0; i++) {
    if (uri[i] < 33) {
      /* control characters and spaces are invalid */
      return 0;
    }
    /* Allow everything else here (See #894) */
  }

  /* A relative uri starts with a / character */
  if (uri[0] == '/') {
    /* relative uri */
    return 2;
  }

  /* It could be an absolute uri: */
  /* This function only checks if the uri is valid, not if it is
   * addressing the current server. So civetweb can also be used
   * as a proxy server. */
  for (i = 0; abs_uri_protocols[i].proto != NULL; i++) {
    if (mg_strncasecmp(uri,
                       abs_uri_protocols[i].proto,
                       abs_uri_protocols[i].proto_len)
        == 0) {

      hostend = strchr(uri + abs_uri_protocols[i].proto_len, '/');
      if (!hostend) {
        return 0;
      }
      portbegin = strchr(uri + abs_uri_protocols[i].proto_len, ':');
      if (!portbegin) {
        return 3;
      }

      port = strtoul(portbegin + 1, &portend, 10);
      if ((portend != hostend) || (port <= 0) || !is_valid_port(port)) {
        return 0;
      }

      return 4;
    }
  }

  return 0;
}


/* Return NULL or the relative uri at the current server */
static const char *
get_rel_url_at_current_server(const char *uri, const struct mg_connection *conn)
{
  const char *server_domain;
  size_t server_domain_len;
  size_t request_domain_len = 0;
  unsigned long port = 0;
  int i, auth_domain_check_enabled;
  const char *hostbegin = NULL;
  const char *hostend = NULL;
  const char *portbegin;
  char *portend;

  auth_domain_check_enabled =
      !mg_strcasecmp(conn->dom_ctx->config[ENABLE_AUTH_DOMAIN_CHECK], "yes");

  /* DNS is case insensitive, so use case insensitive string compare here
   */
  for (i = 0; abs_uri_protocols[i].proto != NULL; i++) {
    if (mg_strncasecmp(uri,
                       abs_uri_protocols[i].proto,
                       abs_uri_protocols[i].proto_len)
        == 0) {

      hostbegin = uri + abs_uri_protocols[i].proto_len;
      hostend = strchr(hostbegin, '/');
      if (!hostend) {
        return 0;
      }
      portbegin = strchr(hostbegin, ':');
      if ((!portbegin) || (portbegin > hostend)) {
        port = abs_uri_protocols[i].default_port;
        request_domain_len = (size_t)(hostend - hostbegin);
      } else {
        port = strtoul(portbegin + 1, &portend, 10);
        if ((portend != hostend) || (port <= 0)
            || !is_valid_port(port)) {
          return 0;
        }
        request_domain_len = (size_t)(portbegin - hostbegin);
      }
      /* protocol found, port set */
      break;
    }
  }

  if (!port) {
    /* port remains 0 if the protocol is not found */
    return 0;
  }

  /* Check if the request is directed to a different server. */
  /* First check if the port is the same. */
  if (ntohs(USA_IN_PORT_UNSAFE(&conn->client.lsa)) != port) {
    /* Request is directed to a different port */
    return 0;
  }

  /* Finally check if the server corresponds to the authentication
   * domain of the server (the server domain).
   * Allow full matches (like http://mydomain.com/path/file.ext), and
   * allow subdomain matches (like http://www.mydomain.com/path/file.ext),
   * but do not allow substrings (like
   * http://notmydomain.com/path/file.ext
   * or http://mydomain.com.fake/path/file.ext).
   */
  if (auth_domain_check_enabled) {
    server_domain = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
    server_domain_len = strlen(server_domain);
    if ((server_domain_len == 0) || (hostbegin == NULL)) {
      return 0;
    }
    if ((request_domain_len == server_domain_len)
        && (!memcmp(server_domain, hostbegin, server_domain_len))) {
      /* Request is directed to this server - full name match. */
    } else {
      if (request_domain_len < (server_domain_len + 2)) {
        /* Request is directed to another server: The server name
         * is longer than the request name.
         * Drop this case here to avoid overflows in the
         * following checks. */
        return 0;
      }
      if (hostbegin[request_domain_len - server_domain_len - 1] != '.') {
        /* Request is directed to another server: It could be a
         * substring
         * like notmyserver.com */
        return 0;
      }
      if (0
          != memcmp(server_domain,
                    hostbegin + request_domain_len - server_domain_len,
                    server_domain_len)) {
        /* Request is directed to another server:
         * The server name is different. */
        return 0;
      }
    }
  }

  return hostend;
}


static int
get_message(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
  if (ebuf_len > 0) {
    ebuf[0] = '\0';
  }
  *err = 0;

  reset_per_request_attributes(conn);

  if (!conn) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Internal error");
    *err = 500;
    return 0;
  }

  /* Set the time the request was received. This value should be used for
   * timeouts. */
  clock_gettime(CLOCK_MONOTONIC, &(conn->req_time));

  conn->request_len =
      read_message(NULL, conn, conn->buf, conn->buf_size, &conn->data_len);
  DEBUG_ASSERT(conn->request_len < 0 || conn->data_len >= conn->request_len);
  if ((conn->request_len >= 0) && (conn->data_len < conn->request_len)) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Invalid message size");
    *err = 500;
    return 0;
  }

  if ((conn->request_len == 0) && (conn->data_len == conn->buf_size)) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Message too large");
    *err = 413;
    return 0;
  }

  if (conn->request_len <= 0) {
    if (conn->data_len > 0) {
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "Malformed message");
      *err = 400;
    } else {
      /* Server did not recv anything -> just close the connection */
      conn->must_close = 1;
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "No data received");
      *err = 0;
    }
    return 0;
  }
  return 1;
}


static int
get_request(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
  const char *cl;

  conn->connection_type =
      CONNECTION_TYPE_REQUEST; /* request (valid of not) */

  if (!get_message(conn, ebuf, ebuf_len, err)) {
    return 0;
  }

  if (parse_http_request(conn->buf, conn->buf_size, &conn->request_info)
      <= 0) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Bad request");
    *err = 400;
    return 0;
  }

  /* Message is a valid request */

  if (!switch_domain_context(conn)) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Bad request: Host mismatch");
    *err = 400;
    return 0;
  }

#if USE_ZLIB
  if (((cl = get_header(conn->request_info.http_headers,
                        conn->request_info.num_headers,
                        "Accept-Encoding"))
       != NULL)
      && strstr(cl, "gzip")) {
    conn->accept_gzip = 1;
  }
#endif
  if (((cl = get_header(conn->request_info.http_headers,
                        conn->request_info.num_headers,
                        "Transfer-Encoding"))
       != NULL)
      && mg_strcasecmp(cl, "identity")) {
    if (mg_strcasecmp(cl, "chunked")) {
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "Bad request");
      *err = 400;
      return 0;
    }
    conn->is_chunked = 1;
    conn->content_len = 0; /* not yet read */
  } else if ((cl = get_header(conn->request_info.http_headers,
                              conn->request_info.num_headers,
                              "Content-Length"))
             != NULL) {
    /* Request has content length set */
    char *endptr = NULL;
    conn->content_len = strtoll(cl, &endptr, 10);
    if ((endptr == cl) || (conn->content_len < 0)) {
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "Bad request");
      *err = 411;
      return 0;
    }
    /* Publish the content length back to the request info. */
    conn->request_info.content_length = conn->content_len;
  } else {
    /* There is no exception, see RFC7230. */
    conn->content_len = 0;
  }

  return 1;
}


/* conn is assumed to be valid in this internal function */
static int
get_response(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
  const char *cl;

  conn->connection_type =
      CONNECTION_TYPE_RESPONSE; /* response (valid or not) */

  if (!get_message(conn, ebuf, ebuf_len, err)) {
    return 0;
  }

  if (parse_http_response(conn->buf, conn->buf_size, &conn->response_info)
      <= 0) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Bad response");
    *err = 400;
    return 0;
  }

  /* Message is a valid response */

  if (((cl = get_header(conn->response_info.http_headers,
                        conn->response_info.num_headers,
                        "Transfer-Encoding"))
       != NULL)
      && mg_strcasecmp(cl, "identity")) {
    if (mg_strcasecmp(cl, "chunked")) {
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "Bad request");
      *err = 400;
      return 0;
    }
    conn->is_chunked = 1;
    conn->content_len = 0; /* not yet read */
  } else if ((cl = get_header(conn->response_info.http_headers,
                              conn->response_info.num_headers,
                              "Content-Length"))
             != NULL) {
    char *endptr = NULL;
    conn->content_len = strtoll(cl, &endptr, 10);
    if ((endptr == cl) || (conn->content_len < 0)) {
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "Bad request");
      *err = 411;
      return 0;
    }
    /* Publish the content length back to the response info. */
    conn->response_info.content_length = conn->content_len;

    /* TODO: check if it is still used in response_info */
    conn->request_info.content_length = conn->content_len;

    /* TODO: we should also consider HEAD method */
    if (conn->response_info.status_code == 304) {
      conn->content_len = 0;
    }
  } else {
    /* TODO: we should also consider HEAD method */
    if (((conn->response_info.status_code >= 100)
         && (conn->response_info.status_code <= 199))
        || (conn->response_info.status_code == 204)
        || (conn->response_info.status_code == 304)) {
      conn->content_len = 0;
    } else {
      conn->content_len = -1; /* unknown content length */
    }
  }

  return 1;
}


CIVETWEB_API int
mg_get_response(struct mg_connection *conn,
                char *ebuf,
                size_t ebuf_len,
                int timeout)
{
  int err, ret;
  char txt[32]; /* will not overflow */
  char *save_timeout;
  char *new_timeout;

  if (ebuf_len > 0) {
    ebuf[0] = '\0';
  }

  if (!conn) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                ebuf,
                ebuf_len,
                "%s",
                "Parameter error");
    return -1;
  }

  /* Reset the previous responses */
  conn->data_len = 0;

  /* Implementation of API function for HTTP clients */
  save_timeout = conn->dom_ctx->config[REQUEST_TIMEOUT];

  if (timeout >= 0) {
    mg_snprintf(conn, NULL, txt, sizeof(txt), "%i", timeout);
    new_timeout = txt;
  } else {
    new_timeout = NULL;
  }

  conn->dom_ctx->config[REQUEST_TIMEOUT] = new_timeout;
  ret = get_response(conn, ebuf, ebuf_len, &err);
  conn->dom_ctx->config[REQUEST_TIMEOUT] = save_timeout;

  /* TODO: here, the URI is the http response code */
  conn->request_info.local_uri_raw = conn->request_info.request_uri;
  conn->request_info.local_uri = conn->request_info.local_uri_raw;

  /* TODO (mid): Define proper return values - maybe return length?
   * For the first test use <0 for error and >0 for OK */
  return (ret == 0) ? -1 : +1;
}


CIVETWEB_API struct mg_connection *
mg_download(const char *host,
            int port,
            int use_ssl,
            char *ebuf,
            size_t ebuf_len,
            const char *fmt,
            ...)
{
  struct mg_connection *conn;
  va_list ap;
  int i;
  int reqerr;

  if (ebuf_len > 0) {
    ebuf[0] = '\0';
  }

  va_start(ap, fmt);

  /* open a connection */
  conn = mg_connect_client(host, port, use_ssl, ebuf, ebuf_len);

  if (conn != NULL) {
    i = mg_vprintf(conn, fmt, ap);
    if (i <= 0) {
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  ebuf_len,
                  "%s",
                  "Error sending request");
    } else {
      /* make sure the buffer is clear */
      conn->data_len = 0;
      get_response(conn, ebuf, ebuf_len, &reqerr);

      /* TODO: here, the URI is the http response code */
      conn->request_info.local_uri = conn->request_info.request_uri;
    }
  }

  /* if an error occurred, close the connection */
  if ((ebuf[0] != '\0') && (conn != NULL)) {
    mg_close_connection(conn);
    conn = NULL;
  }

  va_end(ap);
  return conn;
}


struct websocket_client_thread_data {
  struct mg_connection *conn;
  mg_websocket_data_handler data_handler;
  mg_websocket_close_handler close_handler;
  void *callback_data;
};


#if defined(USE_WEBSOCKET)
#if defined(_WIN32)
static unsigned __stdcall websocket_client_thread(void *data)
#else
static void *
websocket_client_thread(void *data)
#endif
{
  struct websocket_client_thread_data *cdata =
      (struct websocket_client_thread_data *)data;

  void *user_thread_ptr = NULL;

#if !defined(_WIN32) && !defined(__ZEPHYR__)
  struct sigaction sa;

  /* Ignore SIGPIPE */
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  sigaction(SIGPIPE, &sa, NULL);
#endif

  mg_set_thread_name("ws-clnt");

  if (cdata->conn->phys_ctx) {
    if (cdata->conn->phys_ctx->callbacks.init_thread) {
      /* 3 indicates a websocket client thread */
      /* TODO: check if conn->phys_ctx can be set */
      user_thread_ptr = cdata->conn->phys_ctx->callbacks.init_thread(
          cdata->conn->phys_ctx, 3);
    }
  }

  read_websocket(cdata->conn, cdata->data_handler, cdata->callback_data);

  DEBUG_TRACE("%s", "Websocket client thread exited\n");

  if (cdata->close_handler != NULL) {
    cdata->close_handler(cdata->conn, cdata->callback_data);
  }

  /* The websocket_client context has only this thread. If it runs out,
  set the stop_flag to 2 (= "stopped"). */
  STOP_FLAG_ASSIGN(&cdata->conn->phys_ctx->stop_flag, 2);

  if (cdata->conn->phys_ctx->callbacks.exit_thread) {
    cdata->conn->phys_ctx->callbacks.exit_thread(cdata->conn->phys_ctx,
                                                 3,
                                                 user_thread_ptr);
  }

  mg_free((void *)cdata);

#if defined(_WIN32)
  return 0;
#else
  return NULL;
#endif
}
#endif


static struct mg_connection *
mg_connect_websocket_client_impl(const struct mg_client_options *client_options,
                                 int use_ssl,
                                 char *error_buffer,
                                 size_t error_buffer_size,
                                 const char *path,
                                 const char *origin,
                                 const char *extensions,
                                 mg_websocket_data_handler data_func,
                                 mg_websocket_close_handler close_func,
                                 void *user_data)
{
  struct mg_connection *conn = NULL;

#if defined(USE_WEBSOCKET)
  struct websocket_client_thread_data *thread_data;
  static const char *magic = "x3JJHMbDL1EzLkh9GBhXDw==";

  const char *host = client_options->host;
  int i;

  struct mg_init_data init;
  struct mg_error_data error;

  memset(&init, 0, sizeof(init));
  memset(&error, 0, sizeof(error));
  error.text_buffer_size = error_buffer_size;
  error.text = error_buffer;

#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wformat-nonliteral"
#endif

  /* Establish the client connection and request upgrade */
  conn = mg_connect_client_impl(client_options, use_ssl, &init, &error);

  /* Connection object will be null if something goes wrong */
  if (conn == NULL) {
    /* error_buffer should be already filled ... */
    if (!error_buffer[0]) {
      /* ... if not add an error message */
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  error_buffer,
                  error_buffer_size,
                  "Unexpected error");
    }
    return NULL;
  }

  if (origin != NULL) {
    if (extensions != NULL) {
      i = mg_printf(conn,
                    "GET %s HTTP/1.1\r\n"
                    "Host: %s\r\n"
                    "Upgrade: websocket\r\n"
                    "Connection: Upgrade\r\n"
                    "Sec-WebSocket-Key: %s\r\n"
                    "Sec-WebSocket-Version: 13\r\n"
                    "Sec-WebSocket-Extensions: %s\r\n"
                    "Origin: %s\r\n"
                    "\r\n",
                    path,
                    host,
                    magic,
                    extensions,
                    origin);
    } else {
      i = mg_printf(conn,
                    "GET %s HTTP/1.1\r\n"
                    "Host: %s\r\n"
                    "Upgrade: websocket\r\n"
                    "Connection: Upgrade\r\n"
                    "Sec-WebSocket-Key: %s\r\n"
                    "Sec-WebSocket-Version: 13\r\n"
                    "Origin: %s\r\n"
                    "\r\n",
                    path,
                    host,
                    magic,
                    origin);
    }
  } else {

    if (extensions != NULL) {
      i = mg_printf(conn,
                    "GET %s HTTP/1.1\r\n"
                    "Host: %s\r\n"
                    "Upgrade: websocket\r\n"
                    "Connection: Upgrade\r\n"
                    "Sec-WebSocket-Key: %s\r\n"
                    "Sec-WebSocket-Version: 13\r\n"
                    "Sec-WebSocket-Extensions: %s\r\n"
                    "\r\n",
                    path,
                    host,
                    magic,
                    extensions);
    } else {
      i = mg_printf(conn,
                    "GET %s HTTP/1.1\r\n"
                    "Host: %s\r\n"
                    "Upgrade: websocket\r\n"
                    "Connection: Upgrade\r\n"
                    "Sec-WebSocket-Key: %s\r\n"
                    "Sec-WebSocket-Version: 13\r\n"
                    "\r\n",
                    path,
                    host,
                    magic);
    }
  }
  if (i <= 0) {
    mg_snprintf(conn,
                NULL, /* No truncation check for ebuf */
                error_buffer,
                error_buffer_size,
                "%s",
                "Error sending request");
    mg_close_connection(conn);
    return NULL;
  }

  conn->data_len = 0;
  if (!get_response(conn, error_buffer, error_buffer_size, &i)) {
    mg_close_connection(conn);
    return NULL;
  }
  conn->request_info.local_uri_raw = conn->request_info.request_uri;
  conn->request_info.local_uri = conn->request_info.local_uri_raw;

#if defined(__clang__)
#pragma clang diagnostic pop
#endif

  if (conn->response_info.status_code != 101) {
    /* We sent an "upgrade" request. For a correct websocket
     * protocol handshake, we expect a "101 Continue" response.
     * Otherwise it is a protocol violation. Maybe the HTTP
     * Server does not know websockets. */
    if (!*error_buffer) {
      /* set an error, if not yet set */
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  error_buffer,
                  error_buffer_size,
                  "Unexpected server reply");
    }

    DEBUG_TRACE("Websocket client connect error: %s\r\n", error_buffer);
    mg_close_connection(conn);
    return NULL;
  }

  thread_data = (struct websocket_client_thread_data *)mg_calloc_ctx(
      1, sizeof(struct websocket_client_thread_data), conn->phys_ctx);
  if (!thread_data) {
    DEBUG_TRACE("%s\r\n", "Out of memory");
    mg_close_connection(conn);
    return NULL;
  }

  thread_data->conn = conn;
  thread_data->data_handler = data_func;
  thread_data->close_handler = close_func;
  thread_data->callback_data = user_data;

  conn->phys_ctx->worker_threadids =
      (pthread_t *)mg_calloc_ctx(1, sizeof(pthread_t), conn->phys_ctx);
  if (!conn->phys_ctx->worker_threadids) {
    DEBUG_TRACE("%s\r\n", "Out of memory");
    mg_free(thread_data);
    mg_close_connection(conn);
    return NULL;
  }

  /* Now upgrade to ws/wss client context */
  conn->phys_ctx->user_data = user_data;
  conn->phys_ctx->context_type = CONTEXT_WS_CLIENT;
  conn->phys_ctx->cfg_worker_threads = 1; /* one worker thread */

  /* Start a thread to read the websocket client connection
   * This thread will automatically stop when mg_disconnect is
   * called on the client connection */
  if (mg_start_thread_with_id(websocket_client_thread,
                              thread_data,
                              conn->phys_ctx->worker_threadids)
      != 0) {
    conn->phys_ctx->cfg_worker_threads = 0;
    mg_free(thread_data);
    mg_close_connection(conn);
    conn = NULL;
    DEBUG_TRACE("%s",
                "Websocket client connect thread could not be started\r\n");
  }

#else
  /* Appease "unused parameter" warnings */
  (void)client_options;
  (void)use_ssl;
  (void)error_buffer;
  (void)error_buffer_size;
  (void)path;
  (void)origin;
  (void)extensions;
  (void)user_data;
  (void)data_func;
  (void)close_func;
#endif

  return conn;
}


CIVETWEB_API struct mg_connection *
mg_connect_websocket_client(const char *host,
                            int port,
                            int use_ssl,
                            char *error_buffer,
                            size_t error_buffer_size,
                            const char *path,
                            const char *origin,
                            mg_websocket_data_handler data_func,
                            mg_websocket_close_handler close_func,
                            void *user_data)
{
  struct mg_client_options client_options;
  memset(&client_options, 0, sizeof(client_options));
  client_options.host = host;
  client_options.port = port;

  return mg_connect_websocket_client_impl(&client_options,
                                          use_ssl,
                                          error_buffer,
                                          error_buffer_size,
                                          path,
                                          origin,
                                          NULL,
                                          data_func,
                                          close_func,
                                          user_data);
}


CIVETWEB_API struct mg_connection *
mg_connect_websocket_client_secure(
    const struct mg_client_options *client_options,
    char *error_buffer,
    size_t error_buffer_size,
    const char *path,
    const char *origin,
    mg_websocket_data_handler data_func,
    mg_websocket_close_handler close_func,
    void *user_data)
{
  if (!client_options) {
    return NULL;
  }
  return mg_connect_websocket_client_impl(client_options,
                                          1,
                                          error_buffer,
                                          error_buffer_size,
                                          path,
                                          origin,
                                          NULL,
                                          data_func,
                                          close_func,
                                          user_data);
}


CIVETWEB_API struct mg_connection *
mg_connect_websocket_client_extensions(const char *host,
                                       int port,
                                       int use_ssl,
                                       char *error_buffer,
                                       size_t error_buffer_size,
                                       const char *path,
                                       const char *origin,
                                       const char *extensions,
                                       mg_websocket_data_handler data_func,
                                       mg_websocket_close_handler close_func,
                                       void *user_data)
{
  struct mg_client_options client_options;
  memset(&client_options, 0, sizeof(client_options));
  client_options.host = host;
  client_options.port = port;

  return mg_connect_websocket_client_impl(&client_options,
                                          use_ssl,
                                          error_buffer,
                                          error_buffer_size,
                                          path,
                                          origin,
                                          extensions,
                                          data_func,
                                          close_func,
                                          user_data);
}


CIVETWEB_API struct mg_connection *
mg_connect_websocket_client_secure_extensions(
    const struct mg_client_options *client_options,
    char *error_buffer,
    size_t error_buffer_size,
    const char *path,
    const char *origin,
    const char *extensions,
    mg_websocket_data_handler data_func,
    mg_websocket_close_handler close_func,
    void *user_data)
{
  if (!client_options) {
    return NULL;
  }
  return mg_connect_websocket_client_impl(client_options,
                                          1,
                                          error_buffer,
                                          error_buffer_size,
                                          path,
                                          origin,
                                          extensions,
                                          data_func,
                                          close_func,
                                          user_data);
}


/* Prepare connection data structure */
static void
init_connection(struct mg_connection *conn)
{
  /* Is keep alive allowed by the server */
  int keep_alive_enabled =
      !mg_strcasecmp(conn->dom_ctx->config[ENABLE_KEEP_ALIVE], "yes");

  if (!keep_alive_enabled) {
    conn->must_close = 1;
  }

  /* Important: on new connection, reset the receiving buffer. Credit
   * goes to crule42. */
  conn->data_len = 0;
  conn->handled_requests = 0;
  conn->connection_type = CONNECTION_TYPE_INVALID;
  conn->request_info.acceptedWebSocketSubprotocol = NULL;
  mg_set_user_connection_data(conn, NULL);

#if defined(USE_SERVER_STATS)
  conn->conn_state = 2; /* init */
#endif

  /* call the init_connection callback if assigned */
  if (conn->phys_ctx->callbacks.init_connection != NULL) {
    if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
      void *conn_data = NULL;
      conn->phys_ctx->callbacks.init_connection(conn, &conn_data);
      mg_set_user_connection_data(conn, conn_data);
    }
  }
}


/* Process a connection - may handle multiple requests
 * using the same connection.
 * Must be called with a valid connection (conn  and
 * conn->phys_ctx must be valid).
 */
static void
process_new_connection(struct mg_connection *conn)
{
  struct mg_request_info *ri = &conn->request_info;
  int keep_alive, discard_len;
  char ebuf[100];
  const char *hostend;
  int reqerr, uri_type;

#if defined(USE_SERVER_STATS)
  ptrdiff_t mcon = mg_atomic_inc(&(conn->phys_ctx->active_connections));
  mg_atomic_add(&(conn->phys_ctx->total_connections), 1);
  mg_atomic_max(&(conn->phys_ctx->max_active_connections), mcon);
#endif

  DEBUG_TRACE("Start processing connection from %s",
              conn->request_info.remote_addr);

  /* Loop over multiple requests sent using the same connection
   * (while "keep alive"). */
  do {
    DEBUG_TRACE("calling get_request (%i times for this connection)",
                conn->handled_requests + 1);

#if defined(USE_SERVER_STATS)
    conn->conn_state = 3; /* ready */
#endif

    if (!get_request(conn, ebuf, sizeof(ebuf), &reqerr)) {
      /* The request sent by the client could not be understood by
       * the server, or it was incomplete or a timeout. Send an
       * error message and close the connection. */
      if (reqerr > 0) {
        DEBUG_ASSERT(ebuf[0] != '\0');
        mg_send_http_error(conn, reqerr, "%s", ebuf);
      }

    } else if (strcmp(ri->http_version, "1.0")
               && strcmp(ri->http_version, "1.1")) {
      /* HTTP/2 is not allowed here */
      mg_snprintf(conn,
                  NULL, /* No truncation check for ebuf */
                  ebuf,
                  sizeof(ebuf),
                  "Bad HTTP version: [%s]",
                  ri->http_version);
      mg_send_http_error(conn, 505, "%s", ebuf);
    }

    if (ebuf[0] == '\0') {
      uri_type = get_uri_type(conn->request_info.request_uri);
      switch (uri_type) {
      case 1:
        /* Asterisk */
        conn->request_info.local_uri_raw = 0;
        /* TODO: Deal with '*'. */
        break;
      case 2:
        /* relative uri */
        conn->request_info.local_uri_raw =
            conn->request_info.request_uri;
        break;
      case 3:
      case 4:
        /* absolute uri (with/without port) */
        hostend = get_rel_url_at_current_server(
            conn->request_info.request_uri, conn);
        if (hostend) {
          conn->request_info.local_uri_raw = hostend;
        } else {
          conn->request_info.local_uri_raw = NULL;
        }
        break;
      default:
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    sizeof(ebuf),
                    "Invalid URI");
        mg_send_http_error(conn, 400, "%s", ebuf);
        conn->request_info.local_uri_raw = NULL;
        break;
      }
      conn->request_info.local_uri =
          (char *)conn->request_info.local_uri_raw;
    }

    if (ebuf[0] != '\0') {
      conn->protocol_type = -1;

    } else {
      /* HTTP/1 allows protocol upgrade */
      conn->protocol_type = should_switch_to_protocol(conn);

      if (conn->protocol_type == PROTOCOL_TYPE_HTTP2) {
        /* This will occur, if a HTTP/1.1 request should be upgraded
         * to HTTP/2 - but not if HTTP/2 is negotiated using ALPN.
         * Since most (all?) major browsers only support HTTP/2 using
         * ALPN, this is hard to test and very low priority.
         * Deactivate it (at least for now).
         */
        conn->protocol_type = PROTOCOL_TYPE_HTTP1;
      }
    }

    DEBUG_TRACE("http: %s, error: %s",
                (ri->http_version ? ri->http_version : "none"),
                (ebuf[0] ? ebuf : "none"));

    if (ebuf[0] == '\0') {
      if (conn->request_info.local_uri) {

        /* handle request to local server */
        handle_request_stat_log(conn);

      } else {
        /* TODO: handle non-local request (PROXY) */
        conn->must_close = 1;
      }
    } else {
      conn->must_close = 1;
    }

    /* Response complete. Free header buffer */
    free_buffered_response_header_list(conn);

    if (ri->remote_user != NULL) {
      mg_free((void *)ri->remote_user);
      /* Important! When having connections with and without auth
       * would cause double free and then crash */
      ri->remote_user = NULL;
    }

    /* NOTE(lsm): order is important here. should_keep_alive() call
     * is using parsed request, which will be invalid after
     * memmove's below.
     * Therefore, memorize should_keep_alive() result now for later
     * use in loop exit condition. */
    /* Enable it only if this request is completely discardable. */
    keep_alive = STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)
                 && should_keep_alive(conn) && (conn->content_len >= 0)
                 && (conn->request_len > 0)
                 && ((conn->is_chunked == 4)
                     || (!conn->is_chunked
                         && ((conn->consumed_content == conn->content_len)
                             || ((conn->request_len + conn->content_len)
                                 <= conn->data_len))))
                 && (conn->protocol_type == PROTOCOL_TYPE_HTTP1);

    if (keep_alive) {
      /* Discard all buffered data for this request */
      discard_len =
          ((conn->request_len + conn->content_len) < conn->data_len)
              ? (int)(conn->request_len + conn->content_len)
              : conn->data_len;
      conn->data_len -= discard_len;

      if (conn->data_len > 0) {
        DEBUG_TRACE("discard_len = %d", discard_len);
        memmove(conn->buf,
                conn->buf + discard_len,
                (size_t)conn->data_len);
      }
    }

    DEBUG_ASSERT(conn->data_len >= 0);
    DEBUG_ASSERT(conn->data_len <= conn->buf_size);

    if ((conn->data_len < 0) || (conn->data_len > conn->buf_size)) {
      DEBUG_TRACE("internal error: data_len = %li, buf_size = %li",
                  (long int)conn->data_len,
                  (long int)conn->buf_size);
      break;
    }
    conn->handled_requests++;
  } while (keep_alive);

  DEBUG_TRACE("Done processing connection from %s (%f sec)",
              conn->request_info.remote_addr,
              difftime(time(NULL), conn->conn_birth_time));

  close_connection(conn);

#if defined(USE_SERVER_STATS)
  mg_atomic_add(&(conn->phys_ctx->total_requests), conn->handled_requests);
  mg_atomic_dec(&(conn->phys_ctx->active_connections));
#endif
}


#if defined(ALTERNATIVE_QUEUE)

static void
produce_socket(struct mg_context *ctx, const struct socket *sp)
{
  unsigned int i;

  while (!ctx->stop_flag) {
    for (i = 0; i < ctx->cfg_worker_threads; i++) {
      /* find a free worker slot and signal it */
      if (ctx->client_socks[i].in_use == 2) {
        (void)pthread_mutex_lock(&ctx->thread_mutex);
        if ((ctx->client_socks[i].in_use == 2) && !ctx->stop_flag) {
          ctx->client_socks[i] = *sp;
          ctx->client_socks[i].in_use = 1;
          /* socket has been moved to the consumer */
          (void)pthread_mutex_unlock(&ctx->thread_mutex);
          (void)event_signal(ctx->client_wait_events[i]);
          return;
        }
        (void)pthread_mutex_unlock(&ctx->thread_mutex);
      }
    }
    /* queue is full */
    mg_sleep(1);
  }
  /* must consume */
  set_blocking_mode(sp->sock);
  closesocket(sp->sock);
}


static int
consume_socket(struct mg_context *ctx, struct socket *sp, int thread_index)
{
  DEBUG_TRACE("%s", "going idle");
  (void)pthread_mutex_lock(&ctx->thread_mutex);
  ctx->client_socks[thread_index].in_use = 2;
  (void)pthread_mutex_unlock(&ctx->thread_mutex);

  event_wait(ctx->client_wait_events[thread_index]);

  (void)pthread_mutex_lock(&ctx->thread_mutex);
  *sp = ctx->client_socks[thread_index];
  if (ctx->stop_flag) {
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
    if (sp->in_use == 1) {
      /* must consume */
      set_blocking_mode(sp->sock);
      closesocket(sp->sock);
    }
    return 0;
  }
  (void)pthread_mutex_unlock(&ctx->thread_mutex);
  if (sp->in_use == 1) {
    DEBUG_TRACE("grabbed socket %d, going busy", sp->sock);
    return 1;
  }
  /* must not reach here */
  DEBUG_ASSERT(0);
  return 0;
}

#else /* ALTERNATIVE_QUEUE */

/* Worker threads take accepted socket from the queue */
static int
consume_socket(struct mg_context *ctx, struct socket *sp, int thread_index)
{
  (void)thread_index;

  (void)pthread_mutex_lock(&ctx->thread_mutex);
  DEBUG_TRACE("%s", "going idle");

  /* If the queue is empty, wait. We're idle at this point. */
  while ((ctx->sq_head == ctx->sq_tail)
         && (STOP_FLAG_IS_ZERO(&ctx->stop_flag))) {
    pthread_cond_wait(&ctx->sq_full, &ctx->thread_mutex);
  }

  /* If we're stopping, sq_head may be equal to sq_tail. */
  if (ctx->sq_head > ctx->sq_tail) {
    /* Copy socket from the queue and increment tail */
    *sp = ctx->squeue[ctx->sq_tail % ctx->sq_size];
    ctx->sq_tail++;

    DEBUG_TRACE("grabbed socket %d, going busy", sp ? sp->sock : -1);

    /* Wrap pointers if needed */
    while (ctx->sq_tail > ctx->sq_size) {
      ctx->sq_tail -= ctx->sq_size;
      ctx->sq_head -= ctx->sq_size;
    }
  }

  (void)pthread_cond_signal(&ctx->sq_empty);
  (void)pthread_mutex_unlock(&ctx->thread_mutex);

  return STOP_FLAG_IS_ZERO(&ctx->stop_flag);
}


/* Master thread adds accepted socket to a queue */
static void
produce_socket(struct mg_context *ctx, const struct socket *sp)
{
  int queue_filled;

  (void)pthread_mutex_lock(&ctx->thread_mutex);

  queue_filled = ctx->sq_head - ctx->sq_tail;

  /* If the queue is full, wait */
  while (STOP_FLAG_IS_ZERO(&ctx->stop_flag)
         && (queue_filled >= ctx->sq_size)) {
    ctx->sq_blocked = 1; /* Status information: All threads busy */
#if defined(USE_SERVER_STATS)
    if (queue_filled > ctx->sq_max_fill) {
      ctx->sq_max_fill = queue_filled;
    }
#endif
    (void)pthread_cond_wait(&ctx->sq_empty, &ctx->thread_mutex);
    ctx->sq_blocked = 0; /* Not blocked now */
    queue_filled = ctx->sq_head - ctx->sq_tail;
  }

  if (queue_filled < ctx->sq_size) {
    /* Copy socket to the queue and increment head */
    ctx->squeue[ctx->sq_head % ctx->sq_size] = *sp;
    ctx->sq_head++;
    DEBUG_TRACE("queued socket %d", sp ? sp->sock : -1);
  }

  queue_filled = ctx->sq_head - ctx->sq_tail;
#if defined(USE_SERVER_STATS)
  if (queue_filled > ctx->sq_max_fill) {
    ctx->sq_max_fill = queue_filled;
  }
#endif

  (void)pthread_cond_signal(&ctx->sq_full);
  (void)pthread_mutex_unlock(&ctx->thread_mutex);
}
#endif /* ALTERNATIVE_QUEUE */


static void
worker_thread_run(struct mg_connection *conn)
{
  struct mg_context *ctx = conn->phys_ctx;
  int thread_index;
  struct mg_workerTLS tls;

  mg_set_thread_name("worker");

  tls.is_master = 0;
  tls.thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
#if defined(_WIN32)
  tls.pthread_cond_helper_mutex = CreateEvent(NULL, FALSE, FALSE, NULL);
#endif

  /* Initialize thread local storage before calling any callback */
  pthread_setspecific(sTlsKey, &tls);

  /* Check if there is a user callback */
  if (ctx->callbacks.init_thread) {
    /* call init_thread for a worker thread (type 1), and store the
     * return value */
    tls.user_ptr = ctx->callbacks.init_thread(ctx, 1);
  } else {
    /* No callback: set user pointer to NULL */
    tls.user_ptr = NULL;
  }

  /* Connection structure has been pre-allocated */
  thread_index = (int)(conn - ctx->worker_connections);
  if ((thread_index < 0)
      || ((unsigned)thread_index >= (unsigned)ctx->cfg_worker_threads)) {
    mg_cry_ctx_internal(ctx,
                        "Internal error: Invalid worker index %i",
                        thread_index);
    return;
  }

  /* Request buffers are not pre-allocated. They are private to the
   * request and do not contain any state information that might be
   * of interest to anyone observing a server status.  */
  conn->buf = (char *)mg_malloc_ctx(ctx->max_request_size, conn->phys_ctx);
  if (conn->buf == NULL) {
    mg_cry_ctx_internal(
        ctx,
        "Out of memory: Cannot allocate buffer for worker %i",
        thread_index);
    return;
  }
  conn->buf_size = (int)ctx->max_request_size;

  conn->dom_ctx = &(ctx->dd); /* Use default domain and default host */

  conn->tls_user_ptr = tls.user_ptr; /* store ptr for quick access */

  conn->request_info.user_data = ctx->user_data;
  /* Allocate a mutex for this connection to allow communication both
   * within the request handler and from elsewhere in the application
   */
  if (0 != pthread_mutex_init(&conn->mutex, &pthread_mutex_attr)) {
    mg_free(conn->buf);
    mg_cry_ctx_internal(ctx, "%s", "Cannot create mutex");
    return;
  }

#if defined(USE_SERVER_STATS)
  conn->conn_state = 1; /* not consumed */
#endif

  /* Call consume_socket() even when ctx->stop_flag > 0, to let it
   * signal sq_empty condvar to wake up the master waiting in
   * produce_socket() */
  while (consume_socket(ctx, &conn->client, thread_index)) {

    /* New connections must start with new protocol negotiation */
    tls.alpn_proto = NULL;

#if defined(USE_SERVER_STATS)
    conn->conn_close_time = 0;
#endif
    conn->conn_birth_time = time(NULL);

    /* Fill in IP, port info early so even if SSL setup below fails,
     * error handler would have the corresponding info.
     * Thanks to Johannes Winkelmann for the patch.
     */
    conn->request_info.remote_port =
        ntohs(USA_IN_PORT_UNSAFE(&conn->client.rsa));

    conn->request_info.server_port =
        ntohs(USA_IN_PORT_UNSAFE(&conn->client.lsa));

    sockaddr_to_string(conn->request_info.remote_addr,
                       sizeof(conn->request_info.remote_addr),
                       &conn->client.rsa);

    DEBUG_TRACE("Incoming %sconnection from %s",
                (conn->client.is_ssl ? "SSL " : ""),
                conn->request_info.remote_addr);

    conn->request_info.is_ssl = conn->client.is_ssl;

    if (conn->client.is_ssl) {

#if defined(USE_MBEDTLS)
      /* HTTPS connection */
      if (mbed_ssl_accept(&(conn->ssl),
                          conn->dom_ctx->ssl_ctx,
                          (int *)&(conn->client.sock),
                          conn->phys_ctx)
          == 0) {
        /* conn->dom_ctx is set in get_request */
        /* process HTTPS connection */
        init_connection(conn);
        conn->connection_type = CONNECTION_TYPE_REQUEST;
        conn->protocol_type = PROTOCOL_TYPE_HTTP1;
        process_new_connection(conn);
      } else {
        /* make sure the connection is cleaned up on SSL failure */
        close_connection(conn);
      }

#elif !defined(NO_SSL)
      /* HTTPS connection */
      if (sslize(conn, SSL_accept, NULL)) {
        /* conn->dom_ctx is set in get_request */

        /* Get SSL client certificate information (if set) */
        struct mg_client_cert client_cert;
        if (ssl_get_client_cert_info(conn, &client_cert)) {
          conn->request_info.client_cert = &client_cert;
        }

        /* process HTTPS connection */
#if defined(USE_HTTP2)
        if ((tls.alpn_proto != NULL)
            && (!memcmp(tls.alpn_proto, "\x02h2", 3))) {
          /* process HTTPS/2 connection */
          init_connection(conn);
          conn->connection_type = CONNECTION_TYPE_REQUEST;
          conn->protocol_type = PROTOCOL_TYPE_HTTP2;
          conn->content_len =
              -1;               /* content length is not predefined */
          conn->is_chunked = 0; /* HTTP2 is never chunked */
          process_new_http2_connection(conn);
        } else
#endif
        {
          /* process HTTPS/1.x or WEBSOCKET-SECURE connection */
          init_connection(conn);
          conn->connection_type = CONNECTION_TYPE_REQUEST;
          /* Start with HTTP, WS will be an "upgrade" request later */
          conn->protocol_type = PROTOCOL_TYPE_HTTP1;
          process_new_connection(conn);
        }

        /* Free client certificate info */
        if (conn->request_info.client_cert) {
          mg_free((void *)(conn->request_info.client_cert->subject));
          mg_free((void *)(conn->request_info.client_cert->issuer));
          mg_free((void *)(conn->request_info.client_cert->serial));
          mg_free((void *)(conn->request_info.client_cert->finger));
          /* Free certificate memory */
          X509_free(
              (X509 *)conn->request_info.client_cert->peer_cert);
          conn->request_info.client_cert->peer_cert = 0;
          conn->request_info.client_cert->subject = 0;
          conn->request_info.client_cert->issuer = 0;
          conn->request_info.client_cert->serial = 0;
          conn->request_info.client_cert->finger = 0;
          conn->request_info.client_cert = 0;
        }
      } else {
        /* make sure the connection is cleaned up on SSL failure */
        close_connection(conn);
      }
#endif

    } else {
      /* process HTTP connection */
      init_connection(conn);
      conn->connection_type = CONNECTION_TYPE_REQUEST;
      /* Start with HTTP, WS will be an "upgrade" request later */
      conn->protocol_type = PROTOCOL_TYPE_HTTP1;
      process_new_connection(conn);
    }

    DEBUG_TRACE("%s", "Connection closed");

#if defined(USE_SERVER_STATS)
    conn->conn_close_time = time(NULL);
#endif
  }

  /* Call exit thread user callback */
  if (ctx->callbacks.exit_thread) {
    ctx->callbacks.exit_thread(ctx, 1, tls.user_ptr);
  }

  /* delete thread local storage objects */
  pthread_setspecific(sTlsKey, NULL);
#if defined(_WIN32)
  CloseHandle(tls.pthread_cond_helper_mutex);
#endif
  pthread_mutex_destroy(&conn->mutex);

  /* Free the request buffer. */
  conn->buf_size = 0;
  mg_free(conn->buf);
  conn->buf = NULL;

  /* Free cleaned URI (if any) */
  if (conn->request_info.local_uri != conn->request_info.local_uri_raw) {
    mg_free((void *)conn->request_info.local_uri);
    conn->request_info.local_uri = NULL;
  }

#if defined(USE_SERVER_STATS)
  conn->conn_state = 9; /* done */
#endif

  DEBUG_TRACE("%s", "exiting");
}


/* Threads have different return types on Windows and Unix. */
#if defined(_WIN32)
static unsigned __stdcall worker_thread(void *thread_func_param)
{
  worker_thread_run((struct mg_connection *)thread_func_param);
  return 0;
}
#else
static void *
worker_thread(void *thread_func_param)
{
#if !defined(__ZEPHYR__)
  struct sigaction sa;

  /* Ignore SIGPIPE */
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  sigaction(SIGPIPE, &sa, NULL);
#endif

  worker_thread_run((struct mg_connection *)thread_func_param);
  return NULL;
}
#endif /* _WIN32 */


/* This is an internal function, thus all arguments are expected to be
 * valid - a NULL check is not required. */
static void
accept_new_connection(const struct socket *listener, struct mg_context *ctx)
{
  struct socket so;
  char src_addr[IP_ADDR_STR_LEN];
  socklen_t len = sizeof(so.rsa);
#if !defined(__ZEPHYR__)
  int on = 1;
#endif
  memset(&so, 0, sizeof(so));

  if ((so.sock = accept(listener->sock, &so.rsa.sa, &len))
      == INVALID_SOCKET) {
  } else if (check_acl(ctx, &so.rsa) != 1) {
    sockaddr_to_string(src_addr, sizeof(src_addr), &so.rsa);
    mg_cry_ctx_internal(ctx,
                        "%s: %s is not allowed to connect",
                        __func__,
                        src_addr);
    closesocket(so.sock);
  } else {
    /* Put so socket structure into the queue */
    DEBUG_TRACE("Accepted socket %d", (int)so.sock);
    set_close_on_exec(so.sock, NULL, ctx);
    so.is_ssl = listener->is_ssl;
    so.ssl_redir = listener->ssl_redir;
    if (getsockname(so.sock, &so.lsa.sa, &len) != 0) {
      mg_cry_ctx_internal(ctx,
                          "%s: getsockname() failed: %s",
                          __func__,
                          strerror(ERRNO));
    }

#if !defined(__ZEPHYR__)
    if ((so.lsa.sa.sa_family == AF_INET)
        || (so.lsa.sa.sa_family == AF_INET6)) {
      /* Set TCP keep-alive for TCP sockets (IPv4 and IPv6).
       * This is needed because if HTTP-level keep-alive
       * is enabled, and client resets the connection, server won't get
       * TCP FIN or RST and will keep the connection open forever. With
       * TCP keep-alive, next keep-alive handshake will figure out that
       * the client is down and will close the server end.
       * Thanks to Igor Klopov who suggested the patch. */
      if (setsockopt(so.sock,
                     SOL_SOCKET,
                     SO_KEEPALIVE,
                     (SOCK_OPT_TYPE)&on,
                     sizeof(on))
          != 0) {
        mg_cry_ctx_internal(
            ctx,
            "%s: setsockopt(SOL_SOCKET SO_KEEPALIVE) failed: %s",
            __func__,
            strerror(ERRNO));
      }
    }
#endif

    /* Disable TCP Nagle's algorithm. Normally TCP packets are coalesced
     * to effectively fill up the underlying IP packet payload and
     * reduce the overhead of sending lots of small buffers. However
     * this hurts the server's throughput (ie. operations per second)
     * when HTTP 1.1 persistent connections are used and the responses
     * are relatively small (eg. less than 1400 bytes).
     */
    if ((ctx->dd.config[CONFIG_TCP_NODELAY] != NULL)
        && (!strcmp(ctx->dd.config[CONFIG_TCP_NODELAY], "1"))) {
      if (set_tcp_nodelay(&so, 1) != 0) {
        mg_cry_ctx_internal(
            ctx,
            "%s: setsockopt(IPPROTO_TCP TCP_NODELAY) failed: %s",
            __func__,
            strerror(ERRNO));
      }
    }

    /* The "non blocking" property should already be
     * inherited from the parent socket. Set it for
     * non-compliant socket implementations. */
    set_non_blocking_mode(so.sock);

    so.in_use = 0;
    produce_socket(ctx, &so);
  }
}


static void
master_thread_run(struct mg_context *ctx)
{
  struct mg_workerTLS tls;
  struct mg_pollfd *pfd;
  unsigned int i;
  unsigned int workerthreadcount;

  if (!ctx) {
    return;
  }

  mg_set_thread_name("master");

  /* Increase priority of the master thread */
#if defined(_WIN32)
  SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_ABOVE_NORMAL);
#elif defined(USE_MASTER_THREAD_PRIORITY)
  int min_prio = sched_get_priority_min(SCHED_RR);
  int max_prio = sched_get_priority_max(SCHED_RR);
  if ((min_prio >= 0) && (max_prio >= 0)
      && ((USE_MASTER_THREAD_PRIORITY) <= max_prio)
      && ((USE_MASTER_THREAD_PRIORITY) >= min_prio)) {
    struct sched_param sched_param = {0};
    sched_param.sched_priority = (USE_MASTER_THREAD_PRIORITY);
    pthread_setschedparam(pthread_self(), SCHED_RR, &sched_param);
  }
#endif

  /* Initialize thread local storage */
#if defined(_WIN32)
  tls.pthread_cond_helper_mutex = CreateEvent(NULL, FALSE, FALSE, NULL);
#endif
  tls.is_master = 1;
  pthread_setspecific(sTlsKey, &tls);

  if (ctx->callbacks.init_thread) {
    /* Callback for the master thread (type 0) */
    tls.user_ptr = ctx->callbacks.init_thread(ctx, 0);
  } else {
    tls.user_ptr = NULL;
  }

  /* Lua background script "start" event */
#if defined(USE_LUA)
  if (ctx->lua_background_state) {
    lua_State *lstate = (lua_State *)ctx->lua_background_state;
    pthread_mutex_lock(&ctx->lua_bg_mutex);

    /* call "start()" in Lua */
    lua_getglobal(lstate, "start");
    if (lua_type(lstate, -1) == LUA_TFUNCTION) {
      int ret = lua_pcall(lstate, /* args */ 0, /* results */ 0, 0);
      if (ret != 0) {
        struct mg_connection fc;
        lua_cry(fake_connection(&fc, ctx),
                ret,
                lstate,
                "lua_background_script",
                "start");
      }
    } else {
      lua_pop(lstate, 1);
    }

    /* determine if there is a "log()" function in Lua background script */
    lua_getglobal(lstate, "log");
    if (lua_type(lstate, -1) == LUA_TFUNCTION) {
      ctx->lua_bg_log_available = 1;
    }
    lua_pop(lstate, 1);

    pthread_mutex_unlock(&ctx->lua_bg_mutex);
  }
#endif

  /* Server starts *now* */
  ctx->start_time = time(NULL);

  /* Server accept loop */
  pfd = ctx->listening_socket_fds;
  while (STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
    for (i = 0; i < ctx->num_listening_sockets; i++) {
      pfd[i].fd = ctx->listening_sockets[i].sock;
      pfd[i].events = POLLIN;
    }

    if (mg_poll(pfd,
                ctx->num_listening_sockets,
                SOCKET_TIMEOUT_QUANTUM,
                &(ctx->stop_flag))
        > 0) {
      for (i = 0; i < ctx->num_listening_sockets; i++) {
        /* NOTE(lsm): on QNX, poll() returns POLLRDNORM after the
         * successful poll, and POLLIN is defined as
         * (POLLRDNORM | POLLRDBAND)
         * Therefore, we're checking pfd[i].revents & POLLIN, not
         * pfd[i].revents == POLLIN. */
        if (STOP_FLAG_IS_ZERO(&ctx->stop_flag)
            && (pfd[i].revents & POLLIN)) {
          accept_new_connection(&ctx->listening_sockets[i], ctx);
        }
      }
    }
  }

  /* Here stop_flag is 1 - Initiate shutdown. */
  DEBUG_TRACE("%s", "stopping workers");

  /* Stop signal received: somebody called mg_stop. Quit. */
  close_all_listening_sockets(ctx);

  /* Wakeup workers that are waiting for connections to handle. */
#if defined(ALTERNATIVE_QUEUE)
  for (i = 0; i < ctx->cfg_worker_threads; i++) {
    event_signal(ctx->client_wait_events[i]);
  }
#else
  (void)pthread_mutex_lock(&ctx->thread_mutex);
  pthread_cond_broadcast(&ctx->sq_full);
  (void)pthread_mutex_unlock(&ctx->thread_mutex);
#endif

  /* Join all worker threads to avoid leaking threads. */
  workerthreadcount = ctx->cfg_worker_threads;
  for (i = 0; i < workerthreadcount; i++) {
    if (ctx->worker_threadids[i] != 0) {
      mg_join_thread(ctx->worker_threadids[i]);
    }
  }

#if defined(USE_LUA)
  /* Free Lua state of lua background task */
  if (ctx->lua_background_state) {
    lua_State *lstate = (lua_State *)ctx->lua_background_state;
    ctx->lua_bg_log_available = 0;

    /* call "stop()" in Lua */
    pthread_mutex_lock(&ctx->lua_bg_mutex);
    lua_getglobal(lstate, "stop");
    if (lua_type(lstate, -1) == LUA_TFUNCTION) {
      int ret = lua_pcall(lstate, /* args */ 0, /* results */ 0, 0);
      if (ret != 0) {
        struct mg_connection fc;
        lua_cry(fake_connection(&fc, ctx),
                ret,
                lstate,
                "lua_background_script",
                "stop");
      }
    }
    DEBUG_TRACE("Close Lua background state %p", lstate);
    lua_close(lstate);

    ctx->lua_background_state = 0;
    pthread_mutex_unlock(&ctx->lua_bg_mutex);
  }
#endif

  DEBUG_TRACE("%s", "exiting");

  /* call exit thread callback */
  if (ctx->callbacks.exit_thread) {
    /* Callback for the master thread (type 0) */
    ctx->callbacks.exit_thread(ctx, 0, tls.user_ptr);
  }

#if defined(_WIN32)
  CloseHandle(tls.pthread_cond_helper_mutex);
#endif
  pthread_setspecific(sTlsKey, NULL);

  /* Signal mg_stop() that we're done.
   * WARNING: This must be the very last thing this
   * thread does, as ctx becomes invalid after this line. */
  STOP_FLAG_ASSIGN(&ctx->stop_flag, 2);
}


/* Threads have different return types on Windows and Unix. */
#if defined(_WIN32)
static unsigned __stdcall master_thread(void *thread_func_param)
{
  master_thread_run((struct mg_context *)thread_func_param);
  return 0;
}
#else
static void *
master_thread(void *thread_func_param)
{
#if !defined(__ZEPHYR__)
  struct sigaction sa;

  /* Ignore SIGPIPE */
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  sigaction(SIGPIPE, &sa, NULL);
#endif

  master_thread_run((struct mg_context *)thread_func_param);
  return NULL;
}
#endif /* _WIN32 */


static void
free_context(struct mg_context *ctx)
{
  int i;
  struct mg_handler_info *tmp_rh;

  if (ctx == NULL) {
    return;
  }

  /* Call user callback */
  if (ctx->callbacks.exit_context) {
    ctx->callbacks.exit_context(ctx);
  }

  /* All threads exited, no sync is needed. Destroy thread mutex and
   * condvars
   */
  (void)pthread_mutex_destroy(&ctx->thread_mutex);

#if defined(ALTERNATIVE_QUEUE)
  mg_free(ctx->client_socks);
  if (ctx->client_wait_events != NULL) {
    for (i = 0; (unsigned)i < ctx->cfg_worker_threads; i++) {
      event_destroy(ctx->client_wait_events[i]);
    }
    mg_free(ctx->client_wait_events);
  }
#else
  (void)pthread_cond_destroy(&ctx->sq_empty);
  (void)pthread_cond_destroy(&ctx->sq_full);
  mg_free(ctx->squeue);
#endif

  /* Destroy other context global data structures mutex */
  (void)pthread_mutex_destroy(&ctx->nonce_mutex);

#if defined(USE_LUA)
  (void)pthread_mutex_destroy(&ctx->lua_bg_mutex);
#endif

  /* Deallocate config parameters */
  for (i = 0; i < NUM_OPTIONS; i++) {
    if (ctx->dd.config[i] != NULL) {
#if defined(_MSC_VER)
#pragma warning(suppress : 6001)
#endif
      mg_free(ctx->dd.config[i]);
    }
  }

  /* Deallocate request handlers */
  while (ctx->dd.handlers) {
    tmp_rh = ctx->dd.handlers;
    ctx->dd.handlers = tmp_rh->next;
    mg_free(tmp_rh->uri);
    mg_free(tmp_rh);
  }

#if defined(USE_MBEDTLS)
  if (ctx->dd.ssl_ctx != NULL) {
    mbed_sslctx_uninit(ctx->dd.ssl_ctx);
    mg_free(ctx->dd.ssl_ctx);
    ctx->dd.ssl_ctx = NULL;
  }

#elif !defined(NO_SSL)
  /* Deallocate SSL context */
  if (ctx->dd.ssl_ctx != NULL) {
    void *ssl_ctx = (void *)ctx->dd.ssl_ctx;
    int callback_ret =
        (ctx->callbacks.external_ssl_ctx == NULL)
            ? 0
            : (ctx->callbacks.external_ssl_ctx(&ssl_ctx, ctx->user_data));

    if (callback_ret == 0) {
      SSL_CTX_free(ctx->dd.ssl_ctx);
    }
    /* else: ignore error and omit SSL_CTX_free in case
     * callback_ret is 1 */
  }
#endif /* !NO_SSL */

  /* Deallocate worker thread ID array */
  mg_free(ctx->worker_threadids);

  /* Deallocate worker thread ID array */
  mg_free(ctx->worker_connections);

  /* deallocate system name string */
  mg_free(ctx->systemName);

  /* Deallocate context itself */
  mg_free(ctx);
}


CIVETWEB_API void
mg_stop(struct mg_context *ctx)
{
  pthread_t mt;
  if (!ctx) {
    return;
  }

  /* We don't use a lock here. Calling mg_stop with the same ctx from
   * two threads is not allowed. */
  mt = ctx->masterthreadid;
  if (mt == 0) {
    return;
  }

  ctx->masterthreadid = 0;

  /* Set stop flag, so all threads know they have to exit. */
  STOP_FLAG_ASSIGN(&ctx->stop_flag, 1);

  /* Join timer thread */
#if defined(USE_TIMERS)
  timers_exit(ctx);
#endif

  /* Wait until everything has stopped. */
  while (!STOP_FLAG_IS_TWO(&ctx->stop_flag)) {
    (void)mg_sleep(10);
  }

  /* Wait to stop master thread */
  mg_join_thread(mt);

  /* Close remaining Lua states */
#if defined(USE_LUA)
  lua_ctx_exit(ctx);
#endif

  /* Free memory */
  free_context(ctx);
}


static void
get_system_name(char **sysName)
{
#if defined(_WIN32)
  char name[128];
  DWORD dwVersion = 0;
  DWORD dwMajorVersion = 0;
  DWORD dwMinorVersion = 0;
  DWORD dwBuild = 0;
  BOOL wowRet, isWoW = FALSE;

#if defined(_MSC_VER)
#pragma warning(push)
  /* GetVersion was declared deprecated */
#pragma warning(disable : 4996)
#endif
  dwVersion = GetVersion();
#if defined(_MSC_VER)
#pragma warning(pop)
#endif

  dwMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
  dwMinorVersion = (DWORD)(HIBYTE(LOWORD(dwVersion)));
  dwBuild = ((dwVersion < 0x80000000) ? (DWORD)(HIWORD(dwVersion)) : 0);
  (void)dwBuild;

  wowRet = IsWow64Process(GetCurrentProcess(), &isWoW);

  sprintf(name,
          "Windows %u.%u%s",
          (unsigned)dwMajorVersion,
          (unsigned)dwMinorVersion,
          (wowRet ? (isWoW ? " (WoW64)" : "") : " (?)"));

  *sysName = mg_strdup(name);

#elif defined(__ZEPHYR__)
  *sysName = mg_strdup("Zephyr OS");
#else
  struct utsname name;
  memset(&name, 0, sizeof(name));
  uname(&name);
  *sysName = mg_strdup(name.sysname);
#endif
}


static void
legacy_init(const char **options)
{
  const char *ports_option = config_options[LISTENING_PORTS].default_value;

  if (options) {
    const char **run_options = options;
    const char *optname = config_options[LISTENING_PORTS].name;

    /* Try to find the "listening_ports" option */
    while (*run_options) {
      if (!strcmp(*run_options, optname)) {
        ports_option = run_options[1];
      }
      run_options += 2;
    }
  }

  if (is_ssl_port_used(ports_option)) {
    /* Initialize with SSL support */
    mg_init_library(MG_FEATURES_TLS);
  } else {
    /* Initialize without SSL support */
    mg_init_library(MG_FEATURES_DEFAULT);
  }
}


CIVETWEB_API struct mg_context *
mg_start2(struct mg_init_data *init, struct mg_error_data *error)
{
  struct mg_context *ctx;
  const char *name, *value, *default_value;
  int idx, ok, workerthreadcount;
  unsigned int i;
  int itmp;
  void (*exit_callback)(const struct mg_context *ctx) = 0;
  const char **options =
      ((init != NULL) ? (init->configuration_options) : (NULL));

  struct mg_workerTLS tls;

  if (error != NULL) {
    error->code = MG_ERROR_DATA_CODE_OK;
    error->code_sub = 0;
    if (error->text_buffer_size > 0) {
      *error->text = 0;
    }
  }

  if (mg_init_library_called == 0) {
    /* Legacy INIT, if mg_start is called without mg_init_library.
     * Note: This will cause a memory leak when unloading the library.
     */
    legacy_init(options);
  }
  if (mg_init_library_called == 0) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_LIBRARY_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Library uninitialized");
    }
    return NULL;
  }

  /* Allocate context and initialize reasonable general case defaults. */
  ctx = (struct mg_context *)mg_calloc(1, sizeof(*ctx));
  if (ctx == NULL) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)sizeof(*ctx);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Out of memory");
    }
    return NULL;
  }

  /* Random number generator will initialize at the first call */
  ctx->dd.auth_nonce_mask =
      (uint64_t)get_random() ^ (uint64_t)(ptrdiff_t)(options);

  /* Save started thread index to reuse in other external API calls
   * For the sake of thread synchronization all non-civetweb threads
   * can be considered as single external thread */
  ctx->starter_thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
  tls.is_master = -1; /* Thread calling mg_start */
  tls.thread_idx = ctx->starter_thread_idx;
#if defined(_WIN32)
  tls.pthread_cond_helper_mutex = NULL;
#endif
  pthread_setspecific(sTlsKey, &tls);

  ok = (0 == pthread_mutex_init(&ctx->thread_mutex, &pthread_mutex_attr));
#if !defined(ALTERNATIVE_QUEUE)
  ok &= (0 == pthread_cond_init(&ctx->sq_empty, NULL));
  ok &= (0 == pthread_cond_init(&ctx->sq_full, NULL));
  ctx->sq_blocked = 0;
#endif
  ok &= (0 == pthread_mutex_init(&ctx->nonce_mutex, &pthread_mutex_attr));
#if defined(USE_LUA)
  ok &= (0 == pthread_mutex_init(&ctx->lua_bg_mutex, &pthread_mutex_attr));
#endif
  if (!ok) {
    unsigned error_id = (unsigned)ERRNO;
    const char *err_msg =
        "Cannot initialize thread synchronization objects";
    /* Fatal error - abort start. However, this situation should never
     * occur in practice. */

    mg_cry_ctx_internal(ctx, "%s", err_msg);
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OS_ERROR;
      error->code_sub = error_id;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    mg_free(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  if ((init != NULL) && (init->callbacks != NULL)) {
    /* Set all callbacks except exit_context. */
    ctx->callbacks = *init->callbacks;
    exit_callback = init->callbacks->exit_context;
    /* The exit callback is activated once the context is successfully
     * created. It should not be called, if an incomplete context object
     * is deleted during a failed initialization. */
    ctx->callbacks.exit_context = 0;
  }
  ctx->user_data = ((init != NULL) ? (init->user_data) : (NULL));
  ctx->dd.handlers = NULL;
  ctx->dd.next = NULL;

#if defined(USE_LUA)
  lua_ctx_init(ctx);
#endif

  /* Store options */
  while (options && (name = *options++) != NULL) {
    idx = get_option_index(name);
    if (idx == -1) {
      mg_cry_ctx_internal(ctx, "Invalid option: %s", name);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
        error->code_sub = (unsigned)-1;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Invalid configuration option: %s",
                    name);
      }

      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;

    } else if ((value = *options++) == NULL) {
      mg_cry_ctx_internal(ctx, "%s: option value cannot be NULL", name);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
        error->code_sub = (unsigned)idx;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Invalid configuration option value: %s",
                    name);
      }

      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }
    if (ctx->dd.config[idx] != NULL) {
      /* A duplicate configuration option is not an error - the last
       * option value will be used. */
      mg_cry_ctx_internal(ctx, "warning: %s: duplicate option", name);
      mg_free(ctx->dd.config[idx]);
    }
    ctx->dd.config[idx] = mg_strdup_ctx(value, ctx);
    DEBUG_TRACE("[%s] -> [%s]", name, value);
  }

  /* Set default value if needed */
  for (i = 0; config_options[i].name != NULL; i++) {
    default_value = config_options[i].default_value;
    if ((ctx->dd.config[i] == NULL) && (default_value != NULL)) {
      ctx->dd.config[i] = mg_strdup_ctx(default_value, ctx);
    }
  }

  /* Request size option */
  itmp = atoi(ctx->dd.config[MAX_REQUEST_SIZE]);
  if (itmp < 1024) {
    mg_cry_ctx_internal(ctx,
                        "%s too small",
                        config_options[MAX_REQUEST_SIZE].name);
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
      error->code_sub = (unsigned)MAX_REQUEST_SIZE;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Invalid configuration option value: %s",
                  config_options[MAX_REQUEST_SIZE].name);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
  ctx->max_request_size = (unsigned)itmp;

  /* Queue length */
#if !defined(ALTERNATIVE_QUEUE)
  itmp = atoi(ctx->dd.config[CONNECTION_QUEUE_SIZE]);
  if (itmp < 1) {
    mg_cry_ctx_internal(ctx,
                        "%s too small",
                        config_options[CONNECTION_QUEUE_SIZE].name);
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
      error->code_sub = CONNECTION_QUEUE_SIZE;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Invalid configuration option value: %s",
                  config_options[CONNECTION_QUEUE_SIZE].name);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
  ctx->squeue =
      (struct socket *)mg_calloc((unsigned int)itmp, sizeof(struct socket));
  if (ctx->squeue == NULL) {
    mg_cry_ctx_internal(ctx,
                        "Out of memory: Cannot allocate %s",
                        config_options[CONNECTION_QUEUE_SIZE].name);
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)itmp * (unsigned)sizeof(struct socket);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Out of memory: Cannot allocate %s",
                  config_options[CONNECTION_QUEUE_SIZE].name);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
  ctx->sq_size = itmp;
#endif

  /* Worker thread count option */
  workerthreadcount = atoi(ctx->dd.config[NUM_THREADS]);

  if ((workerthreadcount > MAX_WORKER_THREADS) || (workerthreadcount <= 0)) {
    if (workerthreadcount <= 0) {
      mg_cry_ctx_internal(ctx, "%s", "Invalid number of worker threads");
    } else {
      mg_cry_ctx_internal(ctx, "%s", "Too many worker threads");
    }
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
      error->code_sub = NUM_THREADS;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Invalid configuration option value: %s",
                  config_options[NUM_THREADS].name);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  /* Document root */
#if defined(NO_FILES)
  if (ctx->dd.config[DOCUMENT_ROOT] != NULL) {
    mg_cry_ctx_internal(ctx, "%s", "Document root must not be set");
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
      error->code_sub = (unsigned)DOCUMENT_ROOT;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Invalid configuration option value: %s",
                  config_options[DOCUMENT_ROOT].name);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

  get_system_name(&ctx->systemName);

#if defined(USE_LUA)
  /* If a Lua background script has been configured, start it. */
  ctx->lua_bg_log_available = 0;
  if (ctx->dd.config[LUA_BACKGROUND_SCRIPT] != NULL) {
    char ebuf[256];
    struct vec opt_vec;
    struct vec eq_vec;
    const char *sparams;

    memset(ebuf, 0, sizeof(ebuf));
    pthread_mutex_lock(&ctx->lua_bg_mutex);

    /* Create a Lua state, load all standard libraries and the mg table */
    lua_State *state = mg_lua_context_script_prepare(
        ctx->dd.config[LUA_BACKGROUND_SCRIPT], ctx, ebuf, sizeof(ebuf));
    if (!state) {
      mg_cry_ctx_internal(ctx,
                          "lua_background_script load error: %s",
                          ebuf);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_SCRIPT_ERROR;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Error in script %s: %s",
                    config_options[LUA_BACKGROUND_SCRIPT].name,
                    ebuf);
      }

      pthread_mutex_unlock(&ctx->lua_bg_mutex);

      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }

    /* Add a table with parameters into mg.params */
    sparams = ctx->dd.config[LUA_BACKGROUND_SCRIPT_PARAMS];
    if (sparams && sparams[0]) {
      lua_getglobal(state, "mg");
      lua_pushstring(state, "params");
      lua_newtable(state);

      while ((sparams = next_option(sparams, &opt_vec, &eq_vec))
             != NULL) {
        reg_llstring(
            state, opt_vec.ptr, opt_vec.len, eq_vec.ptr, eq_vec.len);
        if (mg_strncasecmp(sparams, opt_vec.ptr, opt_vec.len) == 0)
          break;
      }
      lua_rawset(state, -3);
      lua_pop(state, 1);
    }

    /* Call script */
    state = mg_lua_context_script_run(state,
                                      ctx->dd.config[LUA_BACKGROUND_SCRIPT],
                                      ctx,
                                      ebuf,
                                      sizeof(ebuf));
    if (!state) {
      mg_cry_ctx_internal(ctx,
                          "lua_background_script start error: %s",
                          ebuf);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_SCRIPT_ERROR;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Error in script %s: %s",
                    config_options[DOCUMENT_ROOT].name,
                    ebuf);
      }
      pthread_mutex_unlock(&ctx->lua_bg_mutex);

      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }

    /* state remains valid */
    ctx->lua_background_state = (void *)state;
    pthread_mutex_unlock(&ctx->lua_bg_mutex);

  } else {
    ctx->lua_background_state = 0;
  }
#endif

  /* Step by step initialization of ctx - depending on build options */
#if !defined(NO_FILESYSTEMS)
  if (!set_gpass_option(ctx, NULL)) {
    const char *err_msg = "Invalid global password file";
    /* Fatal error - abort start. */
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_PASS_FILE;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }
    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

#if defined(USE_MBEDTLS)
  if (!mg_sslctx_init(ctx, NULL)) {
    const char *err_msg = "Error initializing SSL context";
    /* Fatal error - abort start. */
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

#elif !defined(NO_SSL)
  if (!init_ssl_ctx(ctx, NULL)) {
    const char *err_msg = "Error initializing SSL context";
    /* Fatal error - abort start. */
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

  if (!set_ports_option(ctx)) {
    const char *err_msg = "Failed to setup server ports";
    /* Fatal error - abort start. */
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_PORTS_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

#if !defined(_WIN32) && !defined(__ZEPHYR__)
  if (!set_uid_option(ctx)) {
    const char *err_msg = "Failed to run as configured user";
    /* Fatal error - abort start. */
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_USER_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

  if (!set_acl_option(ctx)) {
    const char *err_msg = "Failed to setup access control list";
    /* Fatal error - abort start. */
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_ACL_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  ctx->cfg_worker_threads = ((unsigned int)(workerthreadcount));
  ctx->worker_threadids = (pthread_t *)mg_calloc_ctx(ctx->cfg_worker_threads,
                                                     sizeof(pthread_t),
                                                     ctx);

  if (ctx->worker_threadids == NULL) {
    const char *err_msg = "Not enough memory for worker thread ID array";
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub =
          (unsigned)ctx->cfg_worker_threads * (unsigned)sizeof(pthread_t);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
  ctx->worker_connections =
      (struct mg_connection *)mg_calloc_ctx(ctx->cfg_worker_threads,
                                            sizeof(struct mg_connection),
                                            ctx);
  if (ctx->worker_connections == NULL) {
    const char *err_msg =
        "Not enough memory for worker thread connection array";
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)ctx->cfg_worker_threads
                        * (unsigned)sizeof(struct mg_connection);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

#if defined(ALTERNATIVE_QUEUE)
  ctx->client_wait_events =
      (void **)mg_calloc_ctx(ctx->cfg_worker_threads,
                             sizeof(ctx->client_wait_events[0]),
                             ctx);
  if (ctx->client_wait_events == NULL) {
    const char *err_msg = "Not enough memory for worker event array";
    mg_cry_ctx_internal(ctx, "%s", err_msg);
    mg_free(ctx->worker_threadids);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)ctx->cfg_worker_threads
                        * (unsigned)sizeof(ctx->client_wait_events[0]);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  ctx->client_socks =
      (struct socket *)mg_calloc_ctx(ctx->cfg_worker_threads,
                                     sizeof(ctx->client_socks[0]),
                                     ctx);
  if (ctx->client_socks == NULL) {
    const char *err_msg = "Not enough memory for worker socket array";
    mg_cry_ctx_internal(ctx, "%s", err_msg);
    mg_free(ctx->client_wait_events);
    mg_free(ctx->worker_threadids);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)ctx->cfg_worker_threads
                        * (unsigned)sizeof(ctx->client_socks[0]);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  for (i = 0; (unsigned)i < ctx->cfg_worker_threads; i++) {
    ctx->client_wait_events[i] = event_create();
    if (ctx->client_wait_events[i] == 0) {
      const char *err_msg = "Error creating worker event %i";
      mg_cry_ctx_internal(ctx, err_msg, i);
      while (i > 0) {
        i--;
        event_destroy(ctx->client_wait_events[i]);
      }
      mg_free(ctx->client_socks);
      mg_free(ctx->client_wait_events);
      mg_free(ctx->worker_threadids);

      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_OS_ERROR;
        error->code_sub = ERRNO;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    err_msg,
                    i);
      }

      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }
  }
#endif

#if defined(USE_TIMERS)
  if (timers_init(ctx) != 0) {
    const char *err_msg = "Error creating timers";
    mg_cry_ctx_internal(ctx, "%s", err_msg);

    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OS_ERROR;
      error->code_sub = ERRNO;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  err_msg);
    }

    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

  /* Context has been created - init user libraries */
  if (ctx->callbacks.init_context) {
    ctx->callbacks.init_context(ctx);
  }

  /* From now, the context is successfully created.
   * When it is destroyed, the exit callback should be called. */
  ctx->callbacks.exit_context = exit_callback;
  ctx->context_type = CONTEXT_SERVER; /* server context */

  /* Start worker threads */
  for (i = 0; i < ctx->cfg_worker_threads; i++) {
    /* worker_thread sets up the other fields */
    ctx->worker_connections[i].phys_ctx = ctx;
    if (mg_start_thread_with_id(worker_thread,
                                &ctx->worker_connections[i],
                                &ctx->worker_threadids[i])
        != 0) {

      long error_no = (long)ERRNO;

      /* thread was not created */
      if (i > 0) {
        /* If the second, third, ... thread cannot be created, set a
         * warning, but keep running. */
        mg_cry_ctx_internal(ctx,
                            "Cannot start worker thread %i: error %ld",
                            i + 1,
                            error_no);

        /* If the server initialization should stop here, all
         * threads that have already been created must be stopped
         * first, before any free_context(ctx) call.
         */

      } else {
        /* If the first worker thread cannot be created, stop
         * initialization and free the entire server context. */
        mg_cry_ctx_internal(ctx,
                            "Cannot create threads: error %ld",
                            error_no);

        if (error != NULL) {
          error->code = MG_ERROR_DATA_CODE_OS_ERROR;
          error->code_sub = (unsigned)error_no;
          mg_snprintf(
              NULL,
              NULL, /* No truncation check for error buffers */
              error->text,
              error->text_buffer_size,
              "Cannot create first worker thread: error %ld",
              error_no);
        }

        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
      }
      break;
    }
  }

  /* Start master (listening) thread */
  mg_start_thread_with_id(master_thread, ctx, &ctx->masterthreadid);

  pthread_setspecific(sTlsKey, NULL);
  return ctx;
}


CIVETWEB_API struct mg_context *
mg_start(const struct mg_callbacks *callbacks,
         void *user_data,
         const char **options)
{
  struct mg_init_data init = {0};
  init.callbacks = callbacks;
  init.user_data = user_data;
  init.configuration_options = options;

  return mg_start2(&init, NULL);
}


/* Add an additional domain to an already running web server. */
CIVETWEB_API int
mg_start_domain2(struct mg_context *ctx,
                 const char **options,
                 struct mg_error_data *error)
{
  const char *name;
  const char *value;
  const char *default_value;
  struct mg_domain_context *new_dom;
  struct mg_domain_context *dom;
  int idx, i;

  if (error != NULL) {
    error->code = MG_ERROR_DATA_CODE_OK;
    error->code_sub = 0;
    if (error->text_buffer_size > 0) {
      *error->text = 0;
    }
  }

  if ((ctx == NULL) || (options == NULL)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Invalid parameters");
    }
    return -1;
  }

  if (!STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_SERVER_STOPPED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Server already stopped");
    }
    return -7;
  }

  new_dom = (struct mg_domain_context *)
      mg_calloc_ctx(1, sizeof(struct mg_domain_context), ctx);

  if (!new_dom) {
    /* Out of memory */
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
      error->code_sub = (unsigned)sizeof(struct mg_domain_context);
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Out or memory");
    }
    return -6;
  }

  /* Store options - TODO: unite duplicate code */
  while (options && (name = *options++) != NULL) {
    idx = get_option_index(name);
    if (idx == -1) {
      mg_cry_ctx_internal(ctx, "Invalid option: %s", name);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
        error->code_sub = (unsigned)-1;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Invalid option: %s",
                    name);
      }
      mg_free(new_dom);
      return -2;
    } else if ((value = *options++) == NULL) {
      mg_cry_ctx_internal(ctx, "%s: option value cannot be NULL", name);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
        error->code_sub = idx;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Invalid option value: %s",
                    name);
      }
      mg_free(new_dom);
      return -2;
    }
    if (new_dom->config[idx] != NULL) {
      /* Duplicate option: Later values overwrite earlier ones. */
      mg_cry_ctx_internal(ctx, "warning: %s: duplicate option", name);
      mg_free(new_dom->config[idx]);
    }
    new_dom->config[idx] = mg_strdup_ctx(value, ctx);
    DEBUG_TRACE("[%s] -> [%s]", name, value);
  }

  /* Authentication domain is mandatory */
  /* TODO: Maybe use a new option hostname? */
  if (!new_dom->config[AUTHENTICATION_DOMAIN]) {
    mg_cry_ctx_internal(ctx, "%s", "authentication domain required");
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_MISSING_OPTION;
      error->code_sub = AUTHENTICATION_DOMAIN;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "Mandatory option %s missing",
                  config_options[AUTHENTICATION_DOMAIN].name);
    }
    mg_free(new_dom);
    return -4;
  }

  /* Set default value if needed. Take the config value from
   * ctx as a default value. */
  for (i = 0; config_options[i].name != NULL; i++) {
    default_value = ctx->dd.config[i];
    if ((new_dom->config[i] == NULL) && (default_value != NULL)) {
      new_dom->config[i] = mg_strdup_ctx(default_value, ctx);
    }
  }

  new_dom->handlers = NULL;
  new_dom->next = NULL;
  new_dom->nonce_count = 0;
  new_dom->auth_nonce_mask = get_random() ^ (get_random() << 31);

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  new_dom->shared_lua_websockets = NULL;
#endif

#if !defined(NO_SSL) && !defined(USE_MBEDTLS)
  if (!init_ssl_ctx(ctx, new_dom)) {
    /* Init SSL failed */
    if (error != NULL) {
      error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
      mg_snprintf(NULL,
                  NULL, /* No truncation check for error buffers */
                  error->text,
                  error->text_buffer_size,
                  "%s",
                  "Initializing SSL context failed");
    }
    mg_free(new_dom);
    return -3;
  }
#endif

  /* Add element to linked list. */
  mg_lock_context(ctx);

  idx = 0;
  dom = &(ctx->dd);
  for (;;) {
    if (!mg_strcasecmp(new_dom->config[AUTHENTICATION_DOMAIN],
                       dom->config[AUTHENTICATION_DOMAIN])) {
      /* Domain collision */
      mg_cry_ctx_internal(ctx,
                          "domain %s already in use",
                          new_dom->config[AUTHENTICATION_DOMAIN]);
      if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_DUPLICATE_DOMAIN;
        mg_snprintf(NULL,
                    NULL, /* No truncation check for error buffers */
                    error->text,
                    error->text_buffer_size,
                    "Domain %s specified by %s is already in use",
                    new_dom->config[AUTHENTICATION_DOMAIN],
                    config_options[AUTHENTICATION_DOMAIN].name);
      }
      mg_free(new_dom);
      mg_unlock_context(ctx);
      return -5;
    }

    /* Count number of domains */
    idx++;

    if (dom->next == NULL) {
      dom->next = new_dom;
      break;
    }
    dom = dom->next;
  }

  mg_unlock_context(ctx);

  /* Return domain number */
  return idx;
}


CIVETWEB_API int
mg_start_domain(struct mg_context *ctx, const char **options)
{
  return mg_start_domain2(ctx, options, NULL);
}


/* Feature check API function */
CIVETWEB_API unsigned
mg_check_feature(unsigned feature)
{
  static const unsigned feature_set = 0
  /* Set bits for available features according to API documentation.
   * This bit mask is created at compile time, according to the active
   * preprocessor defines. It is a single const value at runtime. */
#if !defined(NO_FILES)
                                      | MG_FEATURES_FILES
#endif
#if !defined(NO_SSL) || defined(USE_MBEDTLS)
                                      | MG_FEATURES_SSL
#endif
#if !defined(NO_CGI)
                                      | MG_FEATURES_CGI
#endif
#if defined(USE_IPV6)
                                      | MG_FEATURES_IPV6
#endif
#if defined(USE_WEBSOCKET)
                                      | MG_FEATURES_WEBSOCKET
#endif
#if defined(USE_LUA)
                                      | MG_FEATURES_LUA
#endif
#if defined(USE_DUKTAPE)
                                      | MG_FEATURES_SSJS
#endif
#if !defined(NO_CACHING)
                                      | MG_FEATURES_CACHE
#endif
#if defined(USE_SERVER_STATS)
                                      | MG_FEATURES_STATS
#endif
#if defined(USE_ZLIB)
                                      | MG_FEATURES_COMPRESSION
#endif
#if defined(USE_HTTP2)
                                      | MG_FEATURES_HTTP2
#endif
#if defined(USE_X_DOM_SOCKET)
                                      | MG_FEATURES_X_DOMAIN_SOCKET
#endif

  /* Set some extra bits not defined in the API documentation.
   * These bits may change without further notice. */
#if defined(MG_LEGACY_INTERFACE)
                                      | 0x80000000u
#endif
#if defined(MG_EXPERIMENTAL_INTERFACES)
                                      | 0x40000000u
#endif
#if !defined(NO_RESPONSE_BUFFERING)
                                      | 0x20000000u
#endif
#if defined(MEMORY_DEBUGGING)
                                      | 0x10000000u
#endif
      ;
  return (feature & feature_set);
}


static size_t
mg_str_append(char **dst, char *end, const char *src)
{
  size_t len = strlen(src);
  if (*dst != end) {
    /* Append src if enough space, or close dst. */
    if ((size_t)(end - *dst) > len) {
      strcpy(*dst, src);
      *dst += len;
    } else {
      *dst = end;
    }
  }
  return len;
}


/* Get system information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_system_info(char *buffer, int buflen)
{
  char *end, *append_eoobj = NULL, block[256];
  size_t system_info_length = 0;

#if defined(_WIN32)
  static const char eol[] = "\r\n", eoobj[] = "\r\n}\r\n";
#else
  static const char eol[] = "\n", eoobj[] = "\n}\n";
#endif

  if ((buffer == NULL) || (buflen < 1)) {
    buflen = 0;
    end = buffer;
  } else {
    *buffer = 0;
    end = buffer + buflen;
  }
  if (buflen > (int)(sizeof(eoobj) - 1)) {
    /* has enough space to append eoobj */
    append_eoobj = buffer;
    if (end) {
      end -= sizeof(eoobj) - 1;
    }
  }

  system_info_length += mg_str_append(&buffer, end, "{");

  /* Server version */
  {
    const char *version = mg_version();
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s\"version\" : \"%s\"",
                eol,
                version);
    system_info_length += mg_str_append(&buffer, end, block);
  }

  /* System info */
  {
#if defined(_WIN32)
    DWORD dwVersion = 0;
    DWORD dwMajorVersion = 0;
    DWORD dwMinorVersion = 0;
    SYSTEM_INFO si;

    GetSystemInfo(&si);

#if defined(_MSC_VER)
#pragma warning(push)
    /* GetVersion was declared deprecated */
#pragma warning(disable : 4996)
#endif
    dwVersion = GetVersion();
#if defined(_MSC_VER)
#pragma warning(pop)
#endif

    dwMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
    dwMinorVersion = (DWORD)(HIBYTE(LOWORD(dwVersion)));

    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"os\" : \"Windows %u.%u\"",
                eol,
                (unsigned)dwMajorVersion,
                (unsigned)dwMinorVersion);
    system_info_length += mg_str_append(&buffer, end, block);

    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"cpu\" : \"type %u, cores %u, mask %x\"",
                eol,
                (unsigned)si.wProcessorArchitecture,
                (unsigned)si.dwNumberOfProcessors,
                (unsigned)si.dwActiveProcessorMask);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__ZEPHYR__)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"os\" : \"%s %s\"",
                eol,
                "Zephyr OS",
                ZEPHYR_VERSION);
    system_info_length += mg_str_append(&buffer, end, block);
#else
    struct utsname name;
    memset(&name, 0, sizeof(name));
    uname(&name);

    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"os\" : \"%s %s (%s) - %s\"",
                eol,
                name.sysname,
                name.version,
                name.release,
                name.machine);
    system_info_length += mg_str_append(&buffer, end, block);
#endif
  }

  /* Features */
  {
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"features\" : %lu"
                ",%s\"feature_list\" : \"Server:%s%s%s%s%s%s%s%s%s\"",
                eol,
                (unsigned long)mg_check_feature(0xFFFFFFFFu),
                eol,
                mg_check_feature(MG_FEATURES_FILES) ? " Files" : "",
                mg_check_feature(MG_FEATURES_SSL) ? " HTTPS" : "",
                mg_check_feature(MG_FEATURES_CGI) ? " CGI" : "",
                mg_check_feature(MG_FEATURES_IPV6) ? " IPv6" : "",
                mg_check_feature(MG_FEATURES_WEBSOCKET) ? " WebSockets"
                                                        : "",
                mg_check_feature(MG_FEATURES_LUA) ? " Lua" : "",
                mg_check_feature(MG_FEATURES_SSJS) ? " JavaScript" : "",
                mg_check_feature(MG_FEATURES_CACHE) ? " Cache" : "",
                mg_check_feature(MG_FEATURES_STATS) ? " Stats" : "");
    system_info_length += mg_str_append(&buffer, end, block);

#if defined(USE_LUA)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"lua_version\" : \"%u (%s)\"",
                eol,
                (unsigned)LUA_VERSION_NUM,
                LUA_RELEASE);
    system_info_length += mg_str_append(&buffer, end, block);
#endif
#if defined(USE_DUKTAPE)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"javascript\" : \"Duktape %u.%u.%u\"",
                eol,
                (unsigned)DUK_VERSION / 10000,
                ((unsigned)DUK_VERSION / 100) % 100,
                (unsigned)DUK_VERSION % 100);
    system_info_length += mg_str_append(&buffer, end, block);
#endif
  }

  /* Build identifier. If BUILD_DATE is not set, __DATE__ will be used. */
  {
#if defined(BUILD_DATE)
    const char *bd = BUILD_DATE;
#else
#if defined(GCC_DIAGNOSTIC)
#if GCC_VERSION >= 40900
#pragma GCC diagnostic push
    /* Disable idiotic compiler warning -Wdate-time, appeared in gcc5. This
     * does not work in some versions. If "BUILD_DATE" is defined to some
     * string, it is used instead of __DATE__. */
#pragma GCC diagnostic ignored "-Wdate-time"
#endif
#endif
    const char *bd = __DATE__;
#if defined(GCC_DIAGNOSTIC)
#if GCC_VERSION >= 40900
#pragma GCC diagnostic pop
#endif
#endif
#endif

    mg_snprintf(
        NULL, NULL, block, sizeof(block), ",%s\"build\" : \"%s\"", eol, bd);

    system_info_length += mg_str_append(&buffer, end, block);
  }

  /* Compiler information */
  /* http://sourceforge.net/p/predef/wiki/Compilers/ */
  {
#if defined(_MSC_VER)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"MSC: %u (%u)\"",
                eol,
                (unsigned)_MSC_VER,
                (unsigned)_MSC_FULL_VER);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__MINGW64__)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"MinGW64: %u.%u\"",
                eol,
                (unsigned)__MINGW64_VERSION_MAJOR,
                (unsigned)__MINGW64_VERSION_MINOR);
    system_info_length += mg_str_append(&buffer, end, block);
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"MinGW32: %u.%u\"",
                eol,
                (unsigned)__MINGW32_MAJOR_VERSION,
                (unsigned)__MINGW32_MINOR_VERSION);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__MINGW32__)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"MinGW32: %u.%u\"",
                eol,
                (unsigned)__MINGW32_MAJOR_VERSION,
                (unsigned)__MINGW32_MINOR_VERSION);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__clang__)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"clang: %u.%u.%u (%s)\"",
                eol,
                __clang_major__,
                __clang_minor__,
                __clang_patchlevel__,
                __clang_version__);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__GNUC__)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"gcc: %u.%u.%u\"",
                eol,
                (unsigned)__GNUC__,
                (unsigned)__GNUC_MINOR__,
                (unsigned)__GNUC_PATCHLEVEL__);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__INTEL_COMPILER)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"Intel C/C++: %u\"",
                eol,
                (unsigned)__INTEL_COMPILER);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__BORLANDC__)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"Borland C: 0x%x\"",
                eol,
                (unsigned)__BORLANDC__);
    system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__SUNPRO_C)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"Solaris: 0x%x\"",
                eol,
                (unsigned)__SUNPRO_C);
    system_info_length += mg_str_append(&buffer, end, block);
#else
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"compiler\" : \"other\"",
                eol);
    system_info_length += mg_str_append(&buffer, end, block);
#endif
  }

  /* Determine 32/64 bit data mode.
   * see https://en.wikipedia.org/wiki/64-bit_computing */
  {
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"data_model\" : \"int:%u/%u/%u/%u, float:%u/%u/%u, "
                "char:%u/%u, "
                "ptr:%u, size:%u, time:%u\"",
                eol,
                (unsigned)sizeof(short),
                (unsigned)sizeof(int),
                (unsigned)sizeof(long),
                (unsigned)sizeof(long long),
                (unsigned)sizeof(float),
                (unsigned)sizeof(double),
                (unsigned)sizeof(long double),
                (unsigned)sizeof(char),
                (unsigned)sizeof(wchar_t),
                (unsigned)sizeof(void *),
                (unsigned)sizeof(size_t),
                (unsigned)sizeof(time_t));
    system_info_length += mg_str_append(&buffer, end, block);
  }

  /* Terminate string */
  if (append_eoobj) {
    strcat(append_eoobj, eoobj);
  }
  system_info_length += sizeof(eoobj) - 1;

  return (int)system_info_length;
}


/* Get context information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_context_info(const struct mg_context *ctx, char *buffer, int buflen)
{
#if defined(USE_SERVER_STATS)
  char *end, *append_eoobj = NULL, block[256];
  size_t context_info_length = 0;

#if defined(_WIN32)
  static const char eol[] = "\r\n", eoobj[] = "\r\n}\r\n";
#else
  static const char eol[] = "\n", eoobj[] = "\n}\n";
#endif
  struct mg_memory_stat *ms = get_memory_stat((struct mg_context *)ctx);

  if ((buffer == NULL) || (buflen < 1)) {
    buflen = 0;
    end = buffer;
  } else {
    *buffer = 0;
    end = buffer + buflen;
  }
  if (buflen > (int)(sizeof(eoobj) - 1)) {
    /* has enough space to append eoobj */
    append_eoobj = buffer;
    end -= sizeof(eoobj) - 1;
  }

  context_info_length += mg_str_append(&buffer, end, "{");

  if (ms) { /* <-- should be always true */
          /* Memory information */
    int blockCount = (int)ms->blockCount;
    int64_t totalMemUsed = ms->totalMemUsed;
    int64_t maxMemUsed = ms->maxMemUsed;
    if (totalMemUsed > maxMemUsed) {
      maxMemUsed = totalMemUsed;
    }

    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s\"memory\" : {%s"
                "\"blocks\" : %i,%s"
                "\"used\" : %" INT64_FMT ",%s"
                "\"maxUsed\" : %" INT64_FMT "%s"
                "}",
                eol,
                eol,
                blockCount,
                eol,
                totalMemUsed,
                eol,
                maxMemUsed,
                eol);
    context_info_length += mg_str_append(&buffer, end, block);
  }

  if (ctx) {
    /* Declare all variables at begin of the block, to comply
     * with old C standards. */
    char start_time_str[64] = {0};
    char now_str[64] = {0};
    time_t start_time = ctx->start_time;
    time_t now = time(NULL);
    int64_t total_data_read, total_data_written;
    int active_connections = (int)ctx->active_connections;
    int max_active_connections = (int)ctx->max_active_connections;
    int total_connections = (int)ctx->total_connections;
    if (active_connections > max_active_connections) {
      max_active_connections = active_connections;
    }
    if (active_connections > total_connections) {
      total_connections = active_connections;
    }

    /* Connections information */
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"connections\" : {%s"
                "\"active\" : %i,%s"
                "\"maxActive\" : %i,%s"
                "\"total\" : %i%s"
                "}",
                eol,
                eol,
                active_connections,
                eol,
                max_active_connections,
                eol,
                total_connections,
                eol);
    context_info_length += mg_str_append(&buffer, end, block);

    /* Queue information */
#if !defined(ALTERNATIVE_QUEUE)
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"queue\" : {%s"
                "\"length\" : %i,%s"
                "\"filled\" : %i,%s"
                "\"maxFilled\" : %i,%s"
                "\"full\" : %s%s"
                "}",
                eol,
                eol,
                ctx->sq_size,
                eol,
                ctx->sq_head - ctx->sq_tail,
                eol,
                ctx->sq_max_fill,
                eol,
                (ctx->sq_blocked ? "true" : "false"),
                eol);
    context_info_length += mg_str_append(&buffer, end, block);
#endif

    /* Requests information */
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"requests\" : {%s"
                "\"total\" : %lu%s"
                "}",
                eol,
                eol,
                (unsigned long)ctx->total_requests,
                eol);
    context_info_length += mg_str_append(&buffer, end, block);

    /* Data information */
    total_data_read =
        mg_atomic_add64((volatile int64_t *)&ctx->total_data_read, 0);
    total_data_written =
        mg_atomic_add64((volatile int64_t *)&ctx->total_data_written, 0);
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"data\" : {%s"
                "\"read\" : %" INT64_FMT ",%s"
                "\"written\" : %" INT64_FMT "%s"
                "}",
                eol,
                eol,
                total_data_read,
                eol,
                total_data_written,
                eol);
    context_info_length += mg_str_append(&buffer, end, block);

    /* Execution time information */
    gmt_time_string(start_time_str,
                    sizeof(start_time_str) - 1,
                    &start_time);
    gmt_time_string(now_str, sizeof(now_str) - 1, &now);

    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                ",%s\"time\" : {%s"
                "\"uptime\" : %.0f,%s"
                "\"start\" : \"%s\",%s"
                "\"now\" : \"%s\"%s"
                "}",
                eol,
                eol,
                difftime(now, start_time),
                eol,
                start_time_str,
                eol,
                now_str,
                eol);
    context_info_length += mg_str_append(&buffer, end, block);
  }

  /* Terminate string */
  if (append_eoobj) {
    strcat(append_eoobj, eoobj);
  }
  context_info_length += sizeof(eoobj) - 1;

  return (int)context_info_length;
#else
  (void)ctx;
  if ((buffer != NULL) && (buflen > 0)) {
    *buffer = 0;
  }
  return 0;
#endif
}


CIVETWEB_API void
mg_disable_connection_keep_alive(struct mg_connection *conn)
{
  /* https://github.com/civetweb/civetweb/issues/727 */
  if (conn != NULL) {
    conn->must_close = 1;
  }
}


#if defined(MG_EXPERIMENTAL_INTERFACES)
/* Get connection information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_connection_info(const struct mg_context *ctx,
                       int idx,
                       char *buffer,
                       int buflen)
{
  const struct mg_connection *conn;
  const struct mg_request_info *ri;
  char *end, *append_eoobj = NULL, block[256];
  size_t connection_info_length = 0;
  int state = 0;
  const char *state_str = "unknown";

#if defined(_WIN32)
  static const char eol[] = "\r\n", eoobj[] = "\r\n}\r\n";
#else
  static const char eol[] = "\n", eoobj[] = "\n}\n";
#endif

  if ((buffer == NULL) || (buflen < 1)) {
    buflen = 0;
    end = buffer;
  } else {
    *buffer = 0;
    end = buffer + buflen;
  }
  if (buflen > (int)(sizeof(eoobj) - 1)) {
    /* has enough space to append eoobj */
    append_eoobj = buffer;
    end -= sizeof(eoobj) - 1;
  }

  if ((ctx == NULL) || (idx < 0)) {
    /* Parameter error */
    return 0;
  }

  if ((unsigned)idx >= ctx->cfg_worker_threads) {
    /* Out of range */
    return 0;
  }

  /* Take connection [idx]. This connection is not locked in
   * any way, so some other thread might use it. */
  conn = (ctx->worker_connections) + idx;

  /* Initialize output string */
  connection_info_length += mg_str_append(&buffer, end, "{");

  /* Init variables */
  ri = &(conn->request_info);

#if defined(USE_SERVER_STATS)
  state = conn->conn_state;

  /* State as string */
  switch (state) {
  case 0:
    state_str = "undefined";
    break;
  case 1:
    state_str = "not used";
    break;
  case 2:
    state_str = "init";
    break;
  case 3:
    state_str = "ready";
    break;
  case 4:
    state_str = "processing";
    break;
  case 5:
    state_str = "processed";
    break;
  case 6:
    state_str = "to close";
    break;
  case 7:
    state_str = "closing";
    break;
  case 8:
    state_str = "closed";
    break;
  case 9:
    state_str = "done";
    break;
  }
#endif

  /* Connection info */
  if ((state >= 3) && (state < 9)) {
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s\"connection\" : {%s"
                "\"remote\" : {%s"
                "\"protocol\" : \"%s\",%s"
                "\"addr\" : \"%s\",%s"
                "\"port\" : %u%s"
                "},%s"
                "\"handled_requests\" : %u%s"
                "}",
                eol,
                eol,
                eol,
                get_proto_name(conn),
                eol,
                ri->remote_addr,
                eol,
                ri->remote_port,
                eol,
                eol,
                conn->handled_requests,
                eol);
    connection_info_length += mg_str_append(&buffer, end, block);
  }

  /* Request info */
  if ((state >= 4) && (state < 6)) {
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s%s\"request_info\" : {%s"
                "\"method\" : \"%s\",%s"
                "\"uri\" : \"%s\",%s"
                "\"query\" : %s%s%s%s"
                "}",
                (connection_info_length > 1 ? "," : ""),
                eol,
                eol,
                ri->request_method,
                eol,
                ri->request_uri,
                eol,
                ri->query_string ? "\"" : "",
                ri->query_string ? ri->query_string : "null",
                ri->query_string ? "\"" : "",
                eol);
    connection_info_length += mg_str_append(&buffer, end, block);
  }

  /* Execution time information */
  if ((state >= 2) && (state < 9)) {
    char start_time_str[64] = {0};
    char close_time_str[64] = {0};
    time_t start_time = conn->conn_birth_time;
    time_t close_time = 0;
    double time_diff;

    gmt_time_string(start_time_str,
                    sizeof(start_time_str) - 1,
                    &start_time);
#if defined(USE_SERVER_STATS)
    close_time = conn->conn_close_time;
#endif
    if (close_time != 0) {
      time_diff = difftime(close_time, start_time);
      gmt_time_string(close_time_str,
                      sizeof(close_time_str) - 1,
                      &close_time);
    } else {
      time_t now = time(NULL);
      time_diff = difftime(now, start_time);
      close_time_str[0] = 0; /* or use "now" ? */
    }

    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s%s\"time\" : {%s"
                "\"uptime\" : %.0f,%s"
                "\"start\" : \"%s\",%s"
                "\"closed\" : \"%s\"%s"
                "}",
                (connection_info_length > 1 ? "," : ""),
                eol,
                eol,
                time_diff,
                eol,
                start_time_str,
                eol,
                close_time_str,
                eol);
    connection_info_length += mg_str_append(&buffer, end, block);
  }

  /* Remote user name */
  if ((ri->remote_user) && (state < 9)) {
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s%s\"user\" : {%s"
                "\"name\" : \"%s\",%s"
                "}",
                (connection_info_length > 1 ? "," : ""),
                eol,
                eol,
                ri->remote_user,
                eol);
    connection_info_length += mg_str_append(&buffer, end, block);
  }

  /* Data block */
  if (state >= 3) {
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s%s\"data\" : {%s"
                "\"read\" : %" INT64_FMT ",%s"
                "\"written\" : %" INT64_FMT "%s"
                "}",
                (connection_info_length > 1 ? "," : ""),
                eol,
                eol,
                conn->consumed_content,
                eol,
                conn->num_bytes_sent,
                eol);
    connection_info_length += mg_str_append(&buffer, end, block);
  }

  /* State */
  mg_snprintf(NULL,
              NULL,
              block,
              sizeof(block),
              "%s%s\"state\" : \"%s\"",
              (connection_info_length > 1 ? "," : ""),
              eol,
              state_str);
  connection_info_length += mg_str_append(&buffer, end, block);

  /* Terminate string */
  if (append_eoobj) {
    strcat(append_eoobj, eoobj);
  }
  connection_info_length += sizeof(eoobj) - 1;

  return (int)connection_info_length;
}

#if 0
/* Get handler information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_handler_info(struct mg_context *ctx,
                       char *buffer,
                       int buflen)
{
    int handler_info_len = 0;
    struct mg_handler_info *tmp_rh;
    mg_lock_context(ctx);

    for (tmp_rh = ctx->dd.handlers; tmp_rh != NULL; tmp_rh = tmp_rh->next) {

        if (buflen > handler_info_len+ tmp_rh->uri_len) {
        memcpy(buffer+handler_info_len, tmp_rh->uri, tmp_rh->uri_len);
        }
        handler_info_len += tmp_rh->uri_len;

        switch (tmp_rh->handler_type) {
            case REQUEST_HANDLER:
                (void)tmp_rh->handler;
            break;
            case WEBSOCKET_HANDLER:
        (void)tmp_rh->connect_handler;
       (void) tmp_rh->ready_handler;
       (void) tmp_rh->data_handler;
       (void) tmp_rh->close_handler;
            break;
            case AUTH_HANDLER:
             (void) tmp_rh->auth_handler;
            break;
        }
        (void)cbdata;
    }

    mg_unlock_context(ctx);
    return handler_info_len;
}
#endif
#endif


/* Initialize this library. This function does not need to be thread safe.
 */
CIVETWEB_API unsigned
mg_init_library(unsigned features)
{
  unsigned features_to_init = mg_check_feature(features & 0xFFu);
  unsigned features_inited = features_to_init;

  if (mg_init_library_called <= 0) {
    /* Not initialized yet */
    if (0 != pthread_mutex_init(&global_lock_mutex, NULL)) {
      return 0;
    }
  }

  mg_global_lock();

  if (mg_init_library_called <= 0) {
    int i, len;

#if defined(_WIN32)
    int file_mutex_init = 1;
    int wsa = 1;
#else
    int mutexattr_init = 1;
#endif
    int failed = 1;
    int key_create = pthread_key_create(&sTlsKey, tls_dtor);

    if (key_create == 0) {
#if defined(_WIN32)
      file_mutex_init =
          pthread_mutex_init(&global_log_file_lock, &pthread_mutex_attr);
      if (file_mutex_init == 0) {
        /* Start WinSock */
        WSADATA data;
        failed = wsa = WSAStartup(MAKEWORD(2, 2), &data);
      }
#else
      mutexattr_init = pthread_mutexattr_init(&pthread_mutex_attr);
      if (mutexattr_init == 0) {
        failed = pthread_mutexattr_settype(&pthread_mutex_attr,
                                           PTHREAD_MUTEX_RECURSIVE);
      }
#endif
    }

    if (failed) {
#if defined(_WIN32)
      if (wsa == 0) {
        (void)WSACleanup();
      }
      if (file_mutex_init == 0) {
        (void)pthread_mutex_destroy(&global_log_file_lock);
      }
#else
      if (mutexattr_init == 0) {
        (void)pthread_mutexattr_destroy(&pthread_mutex_attr);
      }
#endif
      if (key_create == 0) {
        (void)pthread_key_delete(sTlsKey);
      }
      mg_global_unlock();
      (void)pthread_mutex_destroy(&global_lock_mutex);
      return 0;
    }

    len = 1;
    for (i = 0; http_methods[i].name != NULL; i++) {
      size_t sl = strlen(http_methods[i].name);
      len += (int)sl;
      if (i > 0) {
        len += 2;
      }
    }
    all_methods = (char *)mg_malloc(len);
    if (!all_methods) {
      /* Must never happen */
      mg_global_unlock();
      (void)pthread_mutex_destroy(&global_lock_mutex);
      return 0;
    }
    all_methods[0] = 0;
    for (i = 0; http_methods[i].name != NULL; i++) {
      if (i > 0) {
        strcat(all_methods, ", ");
        strcat(all_methods, http_methods[i].name);
      } else {
        strcpy(all_methods, http_methods[i].name);
      }
    }
  }

#if defined(USE_LUA)
  lua_init_optional_libraries();
#endif

#if (defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)                      \
     || defined(OPENSSL_API_3_0))                                              \
    && !defined(NO_SSL)

  if (features_to_init & MG_FEATURES_SSL) {
    if (!mg_openssl_initialized) {
      char ebuf[128];
      if (initialize_openssl(ebuf, sizeof(ebuf))) {
        mg_openssl_initialized = 1;
      } else {
        (void)ebuf;
        DEBUG_TRACE("Initializing SSL failed: %s", ebuf);
        features_inited &= ~((unsigned)(MG_FEATURES_SSL));
      }
    } else {
      /* ssl already initialized */
    }
  }

#endif

  if (mg_init_library_called <= 0) {
    mg_init_library_called = 1;
  } else {
    mg_init_library_called++;
  }
  mg_global_unlock();

  return features_inited;
}


/* Un-initialize this library. */
CIVETWEB_API unsigned
mg_exit_library(void)
{
  if (mg_init_library_called <= 0) {
    return 0;
  }

  mg_global_lock();

  mg_init_library_called--;
  if (mg_init_library_called == 0) {
#if (defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)) && !defined(NO_SSL)
    if (mg_openssl_initialized) {
      uninitialize_openssl();
      mg_openssl_initialized = 0;
    }
#endif

#if defined(_WIN32)
    (void)WSACleanup();
    (void)pthread_mutex_destroy(&global_log_file_lock);
#else
    (void)pthread_mutexattr_destroy(&pthread_mutex_attr);
#endif

    (void)pthread_key_delete(sTlsKey);

#if defined(USE_LUA)
    lua_exit_optional_libraries();
#endif
    mg_free(all_methods);
    all_methods = NULL;

    mg_global_unlock();
    (void)pthread_mutex_destroy(&global_lock_mutex);
    return 1;
  }

  mg_global_unlock();
  return 1;
}


/* End of civetweb.c */

Coverage Report

Created: 2023-03-26 07:35