/src/samba/lib/util/util.c

Source
/*
   Unix SMB/CIFS implementation.
   Samba utility functions
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Jeremy Allison 2001-2002
   Copyright (C) Simo Sorce 2001-2011
   Copyright (C) Jim McDonough (jmcd@us.ibm.com)  2003.
   Copyright (C) James J Myers 2003
   Copyright (C) Volker Lendecke 2010
   Copyright (C) Swen Schillig 2019

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "replace.h"
#include <talloc.h>
#include <tevent.h>
#include "system/network.h"
#include "system/filesys.h"
#include "system/locale.h"
#include "system/shmem.h"
#include "system/passwd.h"
#include "system/time.h"
#include "system/wait.h"
#include "debug.h"
#include "samba_util.h"
#include "lib/util/select.h"
#include <libgen.h>
#include <gnutls/gnutls.h>

#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif

#undef malloc
#undef strcasecmp
#undef strncasecmp
#undef strdup
#undef realloc
#undef calloc

/**
 * @file
 * @brief Misc utility functions
 */

/**
 Find a suitable temporary directory. The result should be copied immediately
 as it may be overwritten by a subsequent call.
**/
_PUBLIC_ const char *tmpdir(void)
{
  char *p;
  if ((p = getenv("TMPDIR")))
    return p;
  return "/tmp";
}


/**
 Create a tmp file, open it and immediately unlink it.
 If dir is NULL uses tmpdir()
 Returns the file descriptor or -1 on error.
**/
int create_unlink_tmp(const char *dir)
{
  size_t len = strlen(dir ? dir : (dir = tmpdir()));
  char fname[len+25];
  int fd;
  mode_t mask;

  len = snprintf(fname, sizeof(fname), "%s/listenerlock_XXXXXX", dir);
  if (len >= sizeof(fname)) {
    errno = ENOMEM;
    return -1;
  }
  mask = umask(S_IRWXO | S_IRWXG);
  fd = mkstemp(fname);
  umask(mask);
  if (fd == -1) {
    return -1;
  }
  if (unlink(fname) == -1) {
    int sys_errno = errno;
    close(fd);
    errno = sys_errno;
    return -1;
  }
  return fd;
}


/**
 Check if a file exists - call vfs_file_exist for samba files.
**/
_PUBLIC_ bool file_exist(const char *fname)
{
  struct stat st;

  if (stat(fname, &st) != 0) {
    return false;
  }

  return ((S_ISREG(st.st_mode)) || (S_ISFIFO(st.st_mode)));
}

/**
 * @brief Return a files modification time.
 *
 * @param fname  The name of the file.
 *
 * @param mt     A pointer to store the modification time.
 *
 * @return 0 on success, errno otherwise.
 */
_PUBLIC_ int file_modtime(const char *fname, struct timespec *mt)
{
  struct stat st = {0};

  if (stat(fname, &st) != 0) {
    return errno;
  }

  *mt = get_mtimespec(&st);
  return 0;
}

/**
 Check file permissions.
**/

_PUBLIC_ bool file_check_permissions(const char *fname,
             uid_t uid,
             mode_t file_perms,
             struct stat *pst)
{
  int ret;
  struct stat st;

  if (pst == NULL) {
    pst = &st;
  }

  ZERO_STRUCTP(pst);

  ret = stat(fname, pst);
  if (ret != 0) {
    DEBUG(0, ("stat failed on file '%s': %s\n",
       fname, strerror(errno)));
    return false;
  }

  if (pst->st_uid != uid && !uid_wrapper_enabled()) {
    DEBUG(0, ("invalid ownership of file '%s': "
       "owned by uid %u, should be %u\n",
       fname, (unsigned int)pst->st_uid,
       (unsigned int)uid));
    return false;
  }

  if ((pst->st_mode & 0777) != file_perms) {
    DEBUG(0, ("invalid permissions on file "
       "'%s': has 0%o should be 0%o\n", fname,
       (unsigned int)(pst->st_mode & 0777),
       (unsigned int)file_perms));
    return false;
  }

  return true;
}

/**
 Check if a directory exists.
**/

_PUBLIC_ bool directory_exist(const char *dname)
{
  struct stat st;
  bool ret;

  if (stat(dname,&st) != 0) {
    return false;
  }

  ret = S_ISDIR(st.st_mode);
  if(!ret)
    errno = ENOTDIR;
  return ret;
}

/**
 * Try to create the specified directory if it didn't exist.
 * A symlink to a directory is also accepted as a valid existing directory.
 *
 * @retval true if the directory already existed
 * or was successfully created.
 */
_PUBLIC_ bool directory_create_or_exist(const char *dname,
          mode_t dir_perms)
{
  int ret;
  mode_t old_umask;

  /* Create directory */
  old_umask = umask(0);
  ret = mkdir(dname, dir_perms);
  if (ret == -1 && errno != EEXIST) {
    int dbg_level = geteuid() == 0 ? DBGLVL_ERR : DBGLVL_NOTICE;

    DBG_PREFIX(dbg_level,
         ("mkdir failed on directory %s: %s\n",
          dname,
          strerror(errno)));
    umask(old_umask);
    return false;
  }
  umask(old_umask);

  if (ret != 0 && errno == EEXIST) {
    struct stat sbuf;

    ret = lstat(dname, &sbuf);
    if (ret != 0) {
      return false;
    }

    if (S_ISDIR(sbuf.st_mode)) {
      return true;
    }

    if (S_ISLNK(sbuf.st_mode)) {
      ret = stat(dname, &sbuf);
      if (ret != 0) {
        return false;
      }

      if (S_ISDIR(sbuf.st_mode)) {
        return true;
      }
    }

    return false;
  }

  return true;
}

_PUBLIC_ bool directory_create_or_exists_recursive(
    const char *dname,
    mode_t dir_perms)
{
  bool ok;

  ok = directory_create_or_exist(dname, dir_perms);
  if (!ok) {
    if (!directory_exist(dname)) {
      char tmp[PATH_MAX] = {0};
      char *parent = NULL;
      size_t n;

      /* Use the null context */
      n = strlcpy(tmp, dname, sizeof(tmp));
      if (n < strlen(dname)) {
        DBG_ERR("Path too long!\n");
        return false;
      }

      parent = dirname(tmp);
      if (parent == NULL) {
        DBG_ERR("Failed to create dirname!\n");
        return false;
      }

      ok = directory_create_or_exists_recursive(parent,
                  dir_perms);
      if (!ok) {
        return false;
      }

      ok = directory_create_or_exist(dname, dir_perms);
    }
  }

  return ok;
}

/**
 * @brief Try to create a specified directory if it doesn't exist.
 *
 * The function creates a directory with the given uid and permissions if it
 * doesn't exist. If it exists it makes sure the uid and permissions are
 * correct and it will fail if they are different.
 *
 * @param[in]  dname  The directory to create.
 *
 * @param[in]  uid    The uid the directory needs to belong too.
 *
 * @param[in]  dir_perms  The expected permissions of the directory.
 *
 * @return True on success, false on error.
 */
_PUBLIC_ bool directory_create_or_exist_strict(const char *dname,
                 uid_t uid,
                 mode_t dir_perms)
{
  struct stat st;
  bool ok;
  int rc;

  ok = directory_create_or_exist(dname, dir_perms);
  if (!ok) {
    return false;
  }

  rc = lstat(dname, &st);
  if (rc == -1) {
    DEBUG(0, ("lstat failed on created directory %s: %s\n",
        dname, strerror(errno)));
    return false;
  }

  /* Check ownership and permission on existing directory */
  if (!S_ISDIR(st.st_mode)) {
    DEBUG(0, ("directory %s isn't a directory\n",
      dname));
    return false;
  }
  if (st.st_uid != uid && !uid_wrapper_enabled()) {
    DBG_NOTICE("invalid ownership on directory "
        "%s\n", dname);
    return false;
  }
  if ((st.st_mode & 0777) != dir_perms) {
    DEBUG(0, ("invalid permissions on directory "
        "'%s': has 0%o should be 0%o\n", dname,
        (unsigned int)(st.st_mode & 0777), (unsigned int)dir_perms));
    return false;
  }

  return true;
}


/**
 Sleep for a specified number of milliseconds.
**/

_PUBLIC_ void smb_msleep(unsigned int t)
{
  sys_poll_intr(NULL, 0, t);
}

/**
 Get my own name, return in talloc'ed storage.
**/

_PUBLIC_ char *get_myname(TALLOC_CTX *ctx)
{
  char *p;
  char hostname[HOST_NAME_MAX];

  /* get my host name */
  if (gethostname(hostname, sizeof(hostname)) == -1) {
    DEBUG(0,("gethostname failed\n"));
    return NULL;
  }

  /* Ensure null termination. */
  hostname[sizeof(hostname)-1] = '\0';

  /* split off any parts after an initial . */
  p = strchr_m(hostname, '.');
  if (p) {
    *p = 0;
  }

  return talloc_strdup(ctx, hostname);
}

/**
 Check if a process exists. Does this work on all unixes?
**/

_PUBLIC_ bool process_exists_by_pid(pid_t pid)
{
  /* Doing kill with a non-positive pid causes messages to be
   * sent to places we don't want. */
  if (pid <= 0) {
    return false;
  }
  return(kill(pid,0) == 0 || errno != ESRCH);
}

/**
 Simple routine to do POSIX file locking. Cruft in NFS and 64->32 bit mapping
 is dealt with in posix.c
**/

_PUBLIC_ bool fcntl_lock(int fd, int op, off_t offset, off_t count, int type)
{
  struct flock lock;
  int ret;

  DEBUG(8,("fcntl_lock %d %d %.0f %.0f %d\n",fd,op,(double)offset,(double)count,type));

  lock.l_type = type;
  lock.l_whence = SEEK_SET;
  lock.l_start = offset;
  lock.l_len = count;
  lock.l_pid = 0;

  ret = fcntl(fd,op,&lock);

  if (ret == -1 && errno != 0)
    DEBUG(3,("fcntl_lock: fcntl lock gave errno %d (%s)\n",errno,strerror(errno)));

  /* a lock query */
  if (op == F_GETLK) {
    if ((ret != -1) &&
        (lock.l_type != F_UNLCK) &&
        (lock.l_pid != 0) &&
        (lock.l_pid != tevent_cached_getpid())) {
      DEBUG(3,("fcntl_lock: fd %d is locked by pid %d\n",fd,(int)lock.l_pid));
      return true;
    }

    /* it must be not locked or locked by me */
    return false;
  }

  /* a lock set or unset */
  if (ret == -1) {
    DEBUG(3,("fcntl_lock: lock failed at offset %.0f count %.0f op %d type %d (%s)\n",
      (double)offset,(double)count,op,type,strerror(errno)));
    return false;
  }

  /* everything went OK */
  DEBUG(8,("fcntl_lock: Lock call successful\n"));

  return true;
}

struct debug_channel_level {
  int channel;
  int level;
};

static void debugadd_channel_cb(const char *buf, void *private_data)
{
  struct debug_channel_level *dcl =
    (struct debug_channel_level *)private_data;

  DEBUGADDC(dcl->channel, dcl->level,("%s", buf));
}

static void debugadd_cb(const char *buf, void *private_data)
{
  int *plevel = (int *)private_data;
  DEBUGADD(*plevel, ("%s", buf));
}

void print_asc_cb(const uint8_t *buf, int len,
      void (*cb)(const char *buf, void *private_data),
      void *private_data)
{
  int i;
  char s[2];
  s[1] = 0;

  for (i=0; i<len; i++) {
    s[0] = isprint(buf[i]) ? buf[i] : '.';
    cb(s, private_data);
  }
}

void print_asc(int level, const uint8_t *buf,int len)
{
  print_asc_cb(buf, len, debugadd_cb, &level);
}

static void dump_data_block16(const char *prefix, size_t idx,
            const uint8_t *buf, size_t len,
            void (*cb)(const char *buf, void *private_data),
            void *private_data)
{
  size_t prefix_len = strlen(prefix);
  /* 16 (=%04zX) + 2 (=[]) + 1 (='\0') => 19 */
  char tmp[prefix_len + 19];
  size_t i;

  SMB_ASSERT(len <= 16);

  snprintf(tmp, sizeof(tmp), "%s[%04zX]", prefix, idx);
  cb(tmp, private_data);

  for (i=0; i<16; i++) {
    if (i == 8) {
      cb("  ", private_data);
    }
    if (i < len) {
      snprintf(tmp, sizeof(tmp), " %02X", (int)buf[i]);
    } else {
      snprintf(tmp, sizeof(tmp), "   ");
    }
    cb(tmp, private_data);
  }

  cb("   ", private_data);

  if (len == 0) {
    cb("EMPTY   BLOCK\n", private_data);
    return;
  }

  for (i=0; i<len; i++) {
    if (i == 8) {
      cb(" ", private_data);
    }
    print_asc_cb(&buf[i], 1, cb, private_data);
  }

  cb("\n", private_data);
}

/**
 * Write dump of binary data to a callback
 */
void dump_data_cb(const uint8_t *buf, int len,
      bool omit_zero_bytes,
      void (*cb)(const char *buf, void *private_data),
      void *private_data)
{
  int i=0;
  bool skipped = false;

  if (len<=0) return;

  for (i=0;i<len;i+=16) {
    size_t remaining_len = len - i;
    size_t this_len = MIN(remaining_len, 16);
    const uint8_t *this_buf = &buf[i];

    if (omit_zero_bytes && (i > 0) && (remaining_len > 16) &&
        (this_len == 16) && all_zero(this_buf, 16))
    {
      if (!skipped) {
        cb("skipping zero buffer bytes\n",
           private_data);
        skipped = true;
      }
      continue;
    }

    skipped = false;
    dump_data_block16("", i, this_buf, this_len,
          cb, private_data);
  }
}

/**
 * Write dump of binary data to the log file.
 *
 * The data is only written if the log level is at least level.
 */
_PUBLIC_ void dump_data(int level, const uint8_t *buf, int len)
{
  if (!DEBUGLVL(level)) {
    return;
  }
  dump_data_cb(buf, len, false, debugadd_cb, &level);
}

/**
 * Write dump of binary data to the log file.
 *
 * The data is only written if the log level is at least level for
 * debug class dbgc_class.
 */
_PUBLIC_ void dump_data_dbgc(int dbgc_class, int level, const uint8_t *buf, int len)
{
  struct debug_channel_level dcl = { dbgc_class, level };

  if (!DEBUGLVLC(dbgc_class, level)) {
    return;
  }
  dump_data_cb(buf, len, false, debugadd_channel_cb, &dcl);
}

/**
 * Write dump of binary data to the log file.
 *
 * The data is only written if the log level is at least level.
 * 16 zero bytes in a row are omitted
 */
_PUBLIC_ void dump_data_skip_zeros(int level, const uint8_t *buf, int len)
{
  if (!DEBUGLVL(level)) {
    return;
  }
  dump_data_cb(buf, len, true, debugadd_cb, &level);
}

static void fprintf_cb(const char *buf, void *private_data)
{
  FILE *f = (FILE *)private_data;
  fprintf(f, "%s", buf);
}

void dump_data_file(const uint8_t *buf, int len, bool omit_zero_bytes,
        FILE *f)
{
  dump_data_cb(buf, len, omit_zero_bytes, fprintf_cb, f);
}

/**
 * Write dump of compared binary data to a callback
 */
void dump_data_diff_cb(const uint8_t *buf1, size_t len1,
           const uint8_t *buf2, size_t len2,
           bool omit_zero_bytes,
           void (*cb)(const char *buf, void *private_data),
           void *private_data)
{
  size_t len = MAX(len1, len2);
  size_t i;
  bool skipped = false;

  for (i=0; i<len; i+=16) {
    size_t remaining_len = len - i;
    size_t remaining_len1 = 0;
    size_t this_len1 = 0;
    const uint8_t *this_buf1 = NULL;
    size_t remaining_len2 = 0;
    size_t this_len2 = 0;
    const uint8_t *this_buf2 = NULL;

    if (i < len1) {
      remaining_len1 = len1 - i;
      this_len1 = MIN(remaining_len1, 16);
      this_buf1 = &buf1[i];
    }
    if (i < len2) {
      remaining_len2 = len2 - i;
      this_len2 = MIN(remaining_len2, 16);
      this_buf2 = &buf2[i];
    }

    if (omit_zero_bytes && (i > 0) && (remaining_len > 16) &&
        (this_len1 == 16) && all_zero(this_buf1, 16) &&
        (this_len2 == 16) && all_zero(this_buf2, 16))
    {
      if (!skipped) {
        cb("skipping zero buffer bytes\n",
           private_data);
        skipped = true;
      }
      continue;
    }

    skipped = false;

    if ((this_len1 == this_len2) &&
        (memcmp(this_buf1, this_buf2, this_len1) == 0))
    {
      dump_data_block16(" ", i, this_buf1, this_len1,
            cb, private_data);
      continue;
    }

    dump_data_block16("-", i, this_buf1, this_len1,
          cb, private_data);
    dump_data_block16("+", i, this_buf2, this_len2,
          cb, private_data);
  }
}

_PUBLIC_ void dump_data_diff(int dbgc_class, int level,
           bool omit_zero_bytes,
           const uint8_t *buf1, size_t len1,
           const uint8_t *buf2, size_t len2)
{
  struct debug_channel_level dcl = { dbgc_class, level };

  if (!DEBUGLVLC(dbgc_class, level)) {
    return;
  }
  dump_data_diff_cb(buf1,
        len1,
        buf2,
        len2,
        omit_zero_bytes,
        debugadd_channel_cb,
        &dcl);
}

_PUBLIC_ void dump_data_file_diff(FILE *f,
                bool omit_zero_bytes,
                const uint8_t *buf1, size_t len1,
                const uint8_t *buf2, size_t len2)
{
  dump_data_diff_cb(buf1, len1, buf2, len2, omit_zero_bytes, fprintf_cb, f);
}

/**
 malloc that aborts with smb_panic on fail or zero size.
**/

_PUBLIC_ void *smb_xmalloc(size_t size)
{
  void *p;
  if (size == 0)
    smb_panic("smb_xmalloc: called with zero size.\n");
  if ((p = malloc(size)) == NULL)
    smb_panic("smb_xmalloc: malloc fail.\n");
  return p;
}

/**
 Memdup with smb_panic on fail.
**/

_PUBLIC_ void *smb_xmemdup(const void *p, size_t size)
{
  void *p2;
  p2 = smb_xmalloc(size);
  memcpy(p2, p, size);
  return p2;
}

/**
 strdup that aborts on malloc fail.
**/

char *smb_xstrdup(const char *s)
{
#if defined(PARANOID_MALLOC_CHECKER)
#ifdef strdup
#undef strdup
#endif
#endif

#ifndef HAVE_STRDUP
#define strdup rep_strdup
#endif

  char *s1 = strdup(s);
#if defined(PARANOID_MALLOC_CHECKER)
#ifdef strdup
#undef strdup
#endif
#define strdup(s) __ERROR_DONT_USE_STRDUP_DIRECTLY
#endif
  if (!s1) {
    smb_panic("smb_xstrdup: malloc failed");
  }
  return s1;

}

/**
 strndup that aborts on malloc fail.
**/

char *smb_xstrndup(const char *s, size_t n)
{
#if defined(PARANOID_MALLOC_CHECKER)
#ifdef strndup
#undef strndup
#endif
#endif

#if (defined(BROKEN_STRNDUP) || !defined(HAVE_STRNDUP))
#undef HAVE_STRNDUP
#define strndup rep_strndup
#endif

  char *s1 = strndup(s, n);
#if defined(PARANOID_MALLOC_CHECKER)
#ifdef strndup
#undef strndup
#endif
#define strndup(s,n) __ERROR_DONT_USE_STRNDUP_DIRECTLY
#endif
  if (!s1) {
    smb_panic("smb_xstrndup: malloc failed");
  }
  return s1;
}



/**
 Like strdup but for memory.
**/

_PUBLIC_ void *smb_memdup(const void *p, size_t size)
{
  void *p2;
  if (size == 0)
    return NULL;
  p2 = malloc(size);
  if (!p2)
    return NULL;
  memcpy(p2, p, size);
  return p2;
}

/**
 * Write a password to the log file.
 *
 * @note Only actually does something if DEBUG_PASSWORD was defined during
 * compile-time.
 */
_PUBLIC_ void dump_data_pw(const char *msg, const uint8_t * data, size_t len)
{
#ifdef DEBUG_PASSWORD
  DEBUG(11, ("%s", msg));
  if (data != NULL && len > 0)
  {
    dump_data(11, data, len);
  }
#endif
}

static void dump_data_addbuf_cb(const char *buf, void *private_data)
{
  char **str = private_data;
  talloc_asprintf_addbuf(str, "%s", buf);
}

_PUBLIC_ void dump_data_addbuf(const uint8_t *buf, size_t buflen, char **str)
{
  dump_data_cb(buf, buflen, false, dump_data_addbuf_cb, str);
}


/**
 * see if a range of memory is all zero. A NULL pointer is considered
 * to be all zero
 */
_PUBLIC_ bool all_zero(const uint8_t *ptr, size_t size)
{
  size_t i;
  if (!ptr) return true;
  for (i=0;i<size;i++) {
    if (ptr[i]) return false;
  }
  return true;
}

/**
  realloc an array, checking for integer overflow in the array size
*/
_PUBLIC_ void *realloc_array(void *ptr, size_t el_size, unsigned count, bool free_on_fail)
{
#define MAX_MALLOC_SIZE 0x7fffffff
  if (count == 0 ||
      count >= MAX_MALLOC_SIZE/el_size) {
    if (free_on_fail)
      SAFE_FREE(ptr);
    return NULL;
  }
  if (!ptr) {
    return malloc(el_size * count);
  }
  return realloc(ptr, el_size * count);
}

/****************************************************************************
 Type-safe malloc.
****************************************************************************/

void *malloc_array(size_t el_size, unsigned int count)
{
  return realloc_array(NULL, el_size, count, false);
}

/****************************************************************************
 Type-safe memalign
****************************************************************************/

void *memalign_array(size_t el_size, size_t align, unsigned int count)
{
  if (el_size == 0 || count >= MAX_MALLOC_SIZE/el_size) {
    return NULL;
  }

  return memalign(align, el_size*count);
}

/****************************************************************************
 Type-safe calloc.
****************************************************************************/

void *calloc_array(size_t size, size_t nmemb)
{
  if (nmemb >= MAX_MALLOC_SIZE/size) {
    return NULL;
  }
  if (size == 0 || nmemb == 0) {
    return NULL;
  }
  return calloc(nmemb, size);
}

/**
 Trim the specified elements off the front and back of a string.
**/
_PUBLIC_ bool trim_string(char *s, const char *front, const char *back)
{
  bool ret = false;
  size_t front_len;
  size_t back_len;
  size_t len;

  /* Ignore null or empty strings. */
  if (!s || (s[0] == '\0')) {
    return false;
  }
  len = strlen(s);

  front_len = front? strlen(front) : 0;
  back_len  = back? strlen(back) : 0;

  if (front_len) {
    size_t front_trim = 0;

    while (strncmp(s+front_trim, front, front_len)==0) {
      front_trim += front_len;
    }
    if (front_trim > 0) {
      /* Must use memmove here as src & dest can
       * easily overlap. Found by valgrind. JRA. */
      memmove(s, s+front_trim, (len-front_trim)+1);
      len -= front_trim;
      ret=true;
    }
  }

  if (back_len) {
    while ((len >= back_len) && strncmp(s+len-back_len,back,back_len)==0) {
      s[len-back_len]='\0';
      len -= back_len;
      ret=true;
    }
  }
  return ret;
}

/**
 Find the number of 'c' chars in a string
**/
_PUBLIC_ _PURE_ size_t count_chars(const char *s, char c)
{
  size_t count = 0;

  while (*s) {
    if (*s == c) count++;
    s ++;
  }

  return count;
}

/**
 * Routine to get hex characters and turn them into a byte array.
 * the array can be variable length.
 * -  "0xnn" or "0Xnn" is specially catered for.
 * - The first non-hex-digit character (apart from possibly leading "0x"
 *   finishes the conversion and skips the rest of the input.
 * - A single hex-digit character at the end of the string is skipped.
 *
 * valid examples: "0A5D15"; "0x123456"
 */
_PUBLIC_ size_t strhex_to_str(char *p, size_t p_len, const char *strhex, size_t strhex_len)
{
  size_t i = 0;
  size_t num_chars = 0;

  /* skip leading 0x prefix */
  if (strncasecmp(strhex, "0x", 2) == 0) {
    i += 2; /* skip two chars */
  }

  while ((i < strhex_len) && (num_chars < p_len)) {
    bool ok = hex_byte(&strhex[i], (uint8_t *)&p[num_chars]);
    if (!ok) {
      break;
    }
    i += 2;
    num_chars += 1;
  }

  return num_chars;
}

/**
 * Parse a hex string and return a data blob.
 */
_PUBLIC_ DATA_BLOB strhex_to_data_blob(TALLOC_CTX *mem_ctx, const char *strhex)
{
  DATA_BLOB ret_blob = data_blob_talloc(mem_ctx, NULL, strlen(strhex)/2+1);
  if (ret_blob.data == NULL) {
    /* ret_blob.length is already 0 */
    return ret_blob;
  }
  ret_blob.length = strhex_to_str((char *)ret_blob.data, ret_blob.length,
          strhex,
          strlen(strhex));

  return ret_blob;
}

/**
 * Parse a hex dump and return a data blob. Hex dump is structured as
 * is generated from dump_data_cb() elsewhere in this file
 *
 */
_PUBLIC_ DATA_BLOB hexdump_to_data_blob(TALLOC_CTX *mem_ctx, const char *hexdump, size_t hexdump_len)
{
  DATA_BLOB ret_blob = { 0 };
  size_t i = 0;
  size_t char_count = 0;
  /* hexdump line length is 77 chars long. We then use the ASCII representation of the bytes
   * at the end of the final line to calculate how many are in that line, minus the extra space
   * and newline. */
  size_t hexdump_byte_count = (16 * (hexdump_len / 77));
  if (hexdump_len % 77) {
    hexdump_byte_count += ((hexdump_len % 77) - 59 - 2);
  }

  ret_blob = data_blob_talloc(mem_ctx, NULL, hexdump_byte_count+1);
  for (; i+1 < hexdump_len && hexdump[i] != 0 && hexdump[i+1] != 0; i++) {
    if ((i%77) == 0)
      i += 7; /* Skip the offset at the start of the line */
    if ((i%77) < 56) { /* position 56 is after both hex chunks */
      if (hexdump[i] != ' ') {
        char_count += strhex_to_str((char *)&ret_blob.data[char_count],
                  hexdump_byte_count - char_count,
                  &hexdump[i], 2);
        i += 2;
      } else {
        i++;
      }
    } else {
      i++;
    }
  }
  ret_blob.length = char_count;

  return ret_blob;
}

/**
 * Print a buf in hex. Assumes dst is at least (srclen*2)+1 large.
 */
_PUBLIC_ void hex_encode_buf(char *dst, const uint8_t *src, size_t srclen)
{
  size_t i;
  for (i=0; i<srclen; i++) {
    snprintf(dst + i*2, 3, "%02X", src[i]);
  }
  /*
   * Ensure 0-termination for 0-length buffers
   */
  dst[srclen*2] = '\0';
}

/**
 * talloc version of hex_encode_buf()
 */
_PUBLIC_ char *hex_encode_talloc(TALLOC_CTX *mem_ctx, const unsigned char *buff_in, size_t len)
{
  char *hex_buffer;

  hex_buffer = talloc_array(mem_ctx, char, (len*2)+1);
  if (!hex_buffer) {
    return NULL;
  }
  hex_encode_buf(hex_buffer, buff_in, len);
  talloc_set_name_const(hex_buffer, hex_buffer);
  return hex_buffer;
}

/**
  variant of strcmp() that handles NULL ptrs
**/
_PUBLIC_ int strcmp_safe(const char *s1, const char *s2)
{
  if (s1 == s2) {
    return 0;
  }
  if (s1 == NULL || s2 == NULL) {
    return s1?-1:1;
  }
  return strcmp(s1, s2);
}


/**
return the number of bytes occupied by a buffer in ASCII format
the result includes the null termination
limited by 'n' bytes
**/
_PUBLIC_ size_t ascii_len_n(const char *src, size_t n)
{
  size_t len;

  len = strnlen(src, n);
  if (len+1 <= n) {
    len += 1;
  }

  return len;
}

_PUBLIC_ bool mem_equal_const_time(const void *s1, const void *s2, size_t n)
{
  /* Ensure we won't overflow the unsigned index used by gnutls. */
  SMB_ASSERT(n <= UINT_MAX);

  return gnutls_memcmp(s1, s2, n) == 0;
}

struct anonymous_shared_header {
  union {
    size_t length;
    uint8_t pad[16];
  } u;
};

/* Map a shared memory buffer of at least nelem counters. */
void *anonymous_shared_allocate(size_t orig_bufsz)
{
  void *ptr;
  void *buf;
  size_t pagesz = getpagesize();
  size_t pagecnt;
  size_t bufsz = orig_bufsz;
  struct anonymous_shared_header *hdr;

  bufsz += sizeof(*hdr);

  /* round up to full pages */
  pagecnt = bufsz / pagesz;
  if (bufsz % pagesz) {
    pagecnt += 1;
  }
  bufsz = pagesz * pagecnt;

  if (orig_bufsz >= bufsz) {
    /* integer wrap */
    errno = ENOMEM;
    return NULL;
  }

#ifdef MAP_ANON
  /* BSD */
  buf = mmap(NULL, bufsz, PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED,
      -1 /* fd */, 0 /* offset */);
#else
{
  int saved_errno;
  int fd;

  fd = open("/dev/zero", O_RDWR);
  if (fd == -1) {
    return NULL;
  }

  buf = mmap(NULL, bufsz, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED,
       fd, 0 /* offset */);
  saved_errno = errno;
  close(fd);
  errno = saved_errno;
}
#endif

  if (buf == MAP_FAILED) {
    return NULL;
  }

  hdr = (struct anonymous_shared_header *)buf;
  hdr->u.length = bufsz;

  ptr = (void *)(&hdr[1]);

  return ptr;
}

void *anonymous_shared_resize(void *ptr, size_t new_size, bool maymove)
{
#ifdef HAVE_MREMAP
  void *buf;
  size_t pagesz = getpagesize();
  size_t pagecnt;
  size_t bufsz;
  struct anonymous_shared_header *hdr;
  int flags = 0;

  if (ptr == NULL) {
    errno = EINVAL;
    return NULL;
  }

  hdr = (struct anonymous_shared_header *)ptr;
  hdr--;
  if (hdr->u.length > (new_size + sizeof(*hdr))) {
    errno = EINVAL;
    return NULL;
  }

  bufsz = new_size + sizeof(*hdr);

  /* round up to full pages */
  pagecnt = bufsz / pagesz;
  if (bufsz % pagesz) {
    pagecnt += 1;
  }
  bufsz = pagesz * pagecnt;

  if (new_size >= bufsz) {
    /* integer wrap */
    errno = ENOSPC;
    return NULL;
  }

  if (bufsz <= hdr->u.length) {
    return ptr;
  }

  if (maymove) {
    flags = MREMAP_MAYMOVE;
  }

  buf = mremap(hdr, hdr->u.length, bufsz, flags);

  if (buf == MAP_FAILED) {
    errno = ENOSPC;
    return NULL;
  }

  hdr = (struct anonymous_shared_header *)buf;
  hdr->u.length = bufsz;

  ptr = (void *)(&hdr[1]);

  return ptr;
#else
  errno = ENOSPC;
  return NULL;
#endif
}

void anonymous_shared_free(void *ptr)
{
  struct anonymous_shared_header *hdr;

  if (ptr == NULL) {
    return;
  }

  hdr = (struct anonymous_shared_header *)ptr;

  hdr--;

  munmap(hdr, hdr->u.length);
}

#ifdef DEVELOPER
/* used when you want a debugger started at a particular point in the
   code. Mostly useful in code that runs as a child process, where
   normal gdb attach is harder to organise.
*/
void samba_start_debugger(void)
{
  int ready_pipe[2];
  char c;
  int ret;
  pid_t pid;

  ret = pipe(ready_pipe);
  SMB_ASSERT(ret == 0);

  pid = fork();
  SMB_ASSERT(pid >= 0);

  if (pid) {
    c = 0;

    ret = close(ready_pipe[0]);
    SMB_ASSERT(ret == 0);
#if defined(HAVE_PRCTL) && defined(PR_SET_PTRACER)
    /*
     * Make sure the child process can attach a debugger.
     *
     * We don't check the error code as the debugger
     * will tell us if it can't attach.
     */
    (void)prctl(PR_SET_PTRACER, pid, 0, 0, 0);
#endif
    ret = write(ready_pipe[1], &c, 1);
    SMB_ASSERT(ret == 1);

    ret = close(ready_pipe[1]);
    SMB_ASSERT(ret == 0);

    /* Wait for gdb to attach. */
    sleep(2);
  } else {
    char *cmd = NULL;

    ret = close(ready_pipe[1]);
    SMB_ASSERT(ret == 0);

    ret = read(ready_pipe[0], &c, 1);
    SMB_ASSERT(ret == 1);

    ret = close(ready_pipe[0]);
    SMB_ASSERT(ret == 0);

    ret = asprintf(&cmd, "gdb --pid %u", getppid());
    SMB_ASSERT(ret != -1);

    execlp("xterm", "xterm", "-e", cmd, (char *) NULL);
    smb_panic("execlp() failed");
  }
}
#endif

Coverage Report

Created: 2026-05-24 06:47