#include "pycore_interp.h"        // _PyInterpreterState.threads.stacksize

#include "pycore_pythread.h"      // _POSIX_SEMAPHORES

#include "pycore_time.h"          // _PyTime_FromMicrosecondsClamup()

/* Posix threads interface */

#include <stdlib.h>

#include <string.h>

#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)

#define destructor xxdestructor

#endif

#ifndef HAVE_PTHREAD_STUBS

#  include <pthread.h>

#endif

#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)

#undef destructor

#endif

#include <signal.h>

#include <unistd.h>             /* pause(), also getthrid() on OpenBSD */

#ifdef HAVE_GETTID

#   include <unistd.h>          // gettid()

#elif defined(__linux__)

#   include <sys/syscall.h>     /* syscall(SYS_gettid) */

#elif defined(__FreeBSD__)

#   include <pthread_np.h>      /* pthread_getthreadid_np() */

#elif defined(__FreeBSD_kernel__)

#   include <sys/syscall.h>     /* syscall(SYS_thr_self) */

#elif defined(_AIX)

#   include <sys/thread.h>      /* thread_self() */

#elif defined(__NetBSD__)

#   include <lwp.h>             /* _lwp_self() */

#elif defined(__DragonFly__)

#   include <sys/lwp.h>         /* lwp_gettid() */

#elif defined(__sun__) && SIZEOF_LONG >= 8

#   include <thread.h>

#endif

/* The POSIX spec requires that use of pthread_attr_setstacksize

   be conditional on _POSIX_THREAD_ATTR_STACKSIZE being defined. */

#ifdef _POSIX_THREAD_ATTR_STACKSIZE

#ifndef THREAD_STACK_SIZE

#define THREAD_STACK_SIZE       0       /* use default stack size */

#endif

/* The default stack size for new threads on BSD is small enough that

 * we'll get hard crashes instead of 'maximum recursion depth exceeded'

 * exceptions.

 *

 * The default stack size below is the empirically determined minimal stack

 * sizes where a simple recursive function doesn't cause a hard crash.

 *

 * For macOS the value of THREAD_STACK_SIZE is determined in configure.ac

 * as it also depends on the other configure options like chosen sanitizer

 * runtimes.

 */

#if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0

#undef  THREAD_STACK_SIZE

#define THREAD_STACK_SIZE       0x400000

#endif

#if defined(_AIX) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0

#undef  THREAD_STACK_SIZE

#define THREAD_STACK_SIZE       0x200000

#endif

/* bpo-38852: test_threading.test_recursion_limit() checks that 1000 recursive

   Python calls (default recursion limit) doesn't crash, but raise a regular

   RecursionError exception. In debug mode, Python function calls allocates

   more memory on the stack, so use a stack of 8 MiB. */

#if defined(__ANDROID__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0

#   ifdef Py_DEBUG

#   undef  THREAD_STACK_SIZE

#   define THREAD_STACK_SIZE    0x800000

#   endif

#endif

#if defined(__VXWORKS__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0

#undef  THREAD_STACK_SIZE

#define THREAD_STACK_SIZE       0x100000

#endif

/* for safety, ensure a viable minimum stacksize */

#define THREAD_STACK_MIN        0x8000  /* 32 KiB */

#else  /* !_POSIX_THREAD_ATTR_STACKSIZE */

#ifdef THREAD_STACK_SIZE

#error "THREAD_STACK_SIZE defined but _POSIX_THREAD_ATTR_STACKSIZE undefined"

#endif

#endif

/* The POSIX spec says that implementations supporting the sem_*

   family of functions must indicate this by defining

   _POSIX_SEMAPHORES. */

#ifdef _POSIX_SEMAPHORES

/* On FreeBSD 4.x, _POSIX_SEMAPHORES is defined empty, so

   we need to add 0 to make it work there as well. */

#if (_POSIX_SEMAPHORES+0) == -1

#  define HAVE_BROKEN_POSIX_SEMAPHORES

#else

#  include <semaphore.h>

#  include <errno.h>

#endif

#endif

/* Thread sanitizer doesn't currently support sem_clockwait */

#ifdef _Py_THREAD_SANITIZER

#undef HAVE_SEM_CLOCKWAIT

#endif

/* On platforms that don't use standard POSIX threads pthread_sigmask()

 * isn't present.  DEC threads uses sigprocmask() instead as do most

 * other UNIX International compliant systems that don't have the full

 * pthread implementation.

 */

#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)

#  define SET_THREAD_SIGMASK pthread_sigmask

#else

#  define SET_THREAD_SIGMASK sigprocmask

#endif

/*

 * pthread_cond support

 */

#define condattr_monotonic _PyRuntime.threads._condattr_monotonic.ptr

static void

init_condattr(void)

{

#ifdef CONDATTR_MONOTONIC

# define ca _PyRuntime.threads._condattr_monotonic.val

    // XXX We need to check the return code?

    pthread_condattr_init(&ca);

    // XXX We need to run pthread_condattr_destroy() during runtime fini.

    if (pthread_condattr_setclock(&ca, CLOCK_MONOTONIC) == 0) {

        condattr_monotonic = &ca;  // Use monotonic clock

    }

# undef ca

#endif  // CONDATTR_MONOTONIC

}

int

_PyThread_cond_init(PyCOND_T *cond)

{

    return pthread_cond_init(cond, condattr_monotonic);

}

void

_PyThread_cond_after(long long us, struct timespec *abs)

{

    PyTime_t timeout = _PyTime_FromMicrosecondsClamp(us);

    PyTime_t t;

#ifdef CONDATTR_MONOTONIC

    if (condattr_monotonic) {

        // silently ignore error: cannot report error to the caller

        (void)PyTime_MonotonicRaw(&t);

    }

    else

#endif

    {

        // silently ignore error: cannot report error to the caller

        (void)PyTime_TimeRaw(&t);

    }

    t = _PyTime_Add(t, timeout);

    _PyTime_AsTimespec_clamp(t, abs);

}

/* A pthread mutex isn't sufficient to model the Python lock type

 * because, according to Draft 5 of the docs (P1003.4a/D5), both of the

 * following are undefined:

 *  -> a thread tries to lock a mutex it already has locked

 *  -> a thread tries to unlock a mutex locked by a different thread

 * pthread mutexes are designed for serializing threads over short pieces

 * of code anyway, so wouldn't be an appropriate implementation of

 * Python's locks regardless.

 *

 * The pthread_lock struct implements a Python lock as a "locked?" bit

 * and a <condition, mutex> pair.  In general, if the bit can be acquired

 * instantly, it is, else the pair is used to block the thread until the

 * bit is cleared.     9 May 1994 tim@ksr.com

 */

typedef struct {

    char             locked; /* 0=unlocked, 1=locked */

    /* a <cond, mutex> pair to handle an acquire of a locked lock */

    pthread_cond_t   lock_released;

    pthread_mutex_t  mut;

} pthread_lock;

#define CHECK_STATUS(name)  if (status != 0) { perror(name); error = 1; }

#define CHECK_STATUS_PTHREAD(name)  if (status != 0) { fprintf(stderr, \

    "%s: %s\n", name, strerror(status)); error = 1; }

/*

 * Initialization for the current runtime.

 */

static void

PyThread__init_thread(void)

{

    // The library is only initialized once in the process,

    // regardless of how many times the Python runtime is initialized.

    static int lib_initialized = 0;

    if (!lib_initialized) {

        lib_initialized = 1;

#if defined(_AIX) && defined(__GNUC__)

        extern void pthread_init(void);

        pthread_init();

#endif

    }

    init_condattr();

}

/*

 * Thread support.

 */

/* bpo-33015: pythread_callback struct and pythread_wrapper() cast

   "void func(void *)" to "void* func(void *)": always return NULL.

   PyThread_start_new_thread() uses "void func(void *)" type, whereas

   pthread_create() requires a void* return value. */

typedef struct {

    void (*func) (void *);

    void *arg;

} pythread_callback;

static void *

pythread_wrapper(void *arg)

{

    /* copy func and func_arg and free the temporary structure */

    pythread_callback *callback = arg;

    void (*func)(void *) = callback->func;

    void *func_arg = callback->arg;

    free(callback);

    func(func_arg);

    return NULL;

}

static int

do_start_joinable_thread(void (*func)(void *), void *arg, pthread_t* out_id)

{

    pthread_t th;

    int status;

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)

    pthread_attr_t attrs;

#endif

#if defined(THREAD_STACK_SIZE)

    size_t      tss;

#endif

    if (!initialized)

        PyThread_init_thread();

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)

    if (pthread_attr_init(&attrs) != 0)

        return -1;

#endif

#if defined(THREAD_STACK_SIZE)

    PyThreadState *tstate = _PyThreadState_GET();

    size_t stacksize = tstate ? tstate->interp->threads.stacksize : 0;

    tss = (stacksize != 0) ? stacksize : THREAD_STACK_SIZE;

    if (tss != 0) {

        if (pthread_attr_setstacksize(&attrs, tss) != 0) {

            pthread_attr_destroy(&attrs);

            return -1;

        }

    }

#endif

#if defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)

    pthread_attr_setscope(&attrs, PTHREAD_SCOPE_SYSTEM);

#endif

    // Use free() instead of PyMem_RawFree() in pythread_wrapper() to avoid a

    // data race if another thread calls PyMem_SetAllocator() in parallel.

    pythread_callback *callback = malloc(sizeof(pythread_callback));

    if (callback == NULL) {

      return -1;

    }

    callback->func = func;

    callback->arg = arg;

    status = pthread_create(&th,

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)

                             &attrs,

#else

                             (pthread_attr_t*)NULL,

#endif

                             pythread_wrapper, callback);

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)

    pthread_attr_destroy(&attrs);

#endif

    if (status != 0) {

        free(callback);

        return -1;

    }

    *out_id = th;

    return 0;

}

/* Helper to convert pthread_t to PyThread_ident_t. POSIX allows pthread_t to be

   non-arithmetic, e.g., musl typedefs it as a pointer. */

static PyThread_ident_t

_pthread_t_to_ident(pthread_t value) {

// Cast through an integer type of the same size to avoid sign-extension.

#if SIZEOF_PTHREAD_T == SIZEOF_VOID_P

    return (uintptr_t) value;

#elif SIZEOF_PTHREAD_T == SIZEOF_LONG

    return (unsigned long) value;

#elif SIZEOF_PTHREAD_T == SIZEOF_INT

    return (unsigned int) value;

#elif SIZEOF_PTHREAD_T == SIZEOF_LONG_LONG

    return (unsigned long long) value;

#else

#error "Unsupported SIZEOF_PTHREAD_T value"

#endif

}

int

PyThread_start_joinable_thread(void (*func)(void *), void *arg,

                               PyThread_ident_t* ident, PyThread_handle_t* handle) {

    pthread_t th = (pthread_t) 0;

    if (do_start_joinable_thread(func, arg, &th)) {

        return -1;

    }

    *ident = _pthread_t_to_ident(th);

    *handle = (PyThread_handle_t) th;

    assert(th == (pthread_t) *handle);

    return 0;

}

unsigned long

PyThread_start_new_thread(void (*func)(void *), void *arg)

{

    pthread_t th = (pthread_t) 0;

    if (do_start_joinable_thread(func, arg, &th)) {

        return PYTHREAD_INVALID_THREAD_ID;

    }

    pthread_detach(th);

    return (unsigned long) _pthread_t_to_ident(th);;

}

int

PyThread_join_thread(PyThread_handle_t th) {

    return pthread_join((pthread_t) th, NULL);

}

int

PyThread_detach_thread(PyThread_handle_t th) {

    return pthread_detach((pthread_t) th);

}

/* XXX This implementation is considered (to quote Tim Peters) "inherently

   hosed" because:

     - It does not guarantee the promise that a non-zero integer is returned.

     - The cast to unsigned long is inherently unsafe.

     - It is not clear that the 'volatile' (for AIX?) are any longer necessary.

*/

PyThread_ident_t

PyThread_get_thread_ident_ex(void) {

    volatile pthread_t threadid;

    if (!initialized)

        PyThread_init_thread();

    threadid = pthread_self();

    return _pthread_t_to_ident(threadid);

}

unsigned long

PyThread_get_thread_ident(void)

{

    return (unsigned long) PyThread_get_thread_ident_ex();

}

#ifdef PY_HAVE_THREAD_NATIVE_ID

unsigned long

PyThread_get_thread_native_id(void)

{

    if (!initialized)

        PyThread_init_thread();

#ifdef __APPLE__

    uint64_t native_id;

    (void) pthread_threadid_np(NULL, &native_id);

#elif defined(HAVE_GETTID)

    pid_t native_id;

    native_id = gettid();

#elif defined(__linux__)

    pid_t native_id;

    native_id = syscall(SYS_gettid);

#elif defined(__FreeBSD__)

    int native_id;

    native_id = pthread_getthreadid_np();

#elif defined(__FreeBSD_kernel__)

    long native_id;

    syscall(SYS_thr_self, &native_id);

#elif defined(__OpenBSD__)

    pid_t native_id;

    native_id = getthrid();

#elif defined(_AIX)

    tid_t native_id;

    native_id = thread_self();

#elif defined(__NetBSD__)

    lwpid_t native_id;

    native_id = _lwp_self();

#elif defined(__DragonFly__)

    // lwp_gettid() is only unique within a process, so combine it with the pid.

    unsigned long native_id = (unsigned long)getpid() << 32 | lwp_gettid();

#elif defined(__sun__) && SIZEOF_LONG >= 8

    unsigned long native_id = (unsigned long)getpid() << 32 | thr_self();

#endif

    return (unsigned long) native_id;

}

#endif

void _Py_NO_RETURN

PyThread_exit_thread(void)

{

    if (!initialized)

        exit(0);

#if defined(__wasi__)

    /*

     * wasi-threads doesn't have pthread_exit right now

     * cf. https://github.com/WebAssembly/wasi-threads/issues/7

     */

    abort();

#else

    pthread_exit(0);

#endif

}

void _Py_NO_RETURN

PyThread_hang_thread(void)

{

    while (1) {

#if defined(__wasi__)

        sleep(9999999);  // WASI doesn't have pause() ?!

#else

        pause();

#endif

    }

}

/* set the thread stack size.

 * Return 0 if size is valid, -1 if size is invalid,

 * -2 if setting stack size is not supported.

 */

static int

_pythread_pthread_set_stacksize(size_t size)

{

#if defined(THREAD_STACK_SIZE)

    pthread_attr_t attrs;

    size_t tss_min;

    int rc = 0;

#endif

    /* set to default */

    if (size == 0) {

        _PyInterpreterState_GET()->threads.stacksize = 0;

        return 0;

    }

#if defined(THREAD_STACK_SIZE)

#if defined(PTHREAD_STACK_MIN)

    tss_min = PTHREAD_STACK_MIN > THREAD_STACK_MIN ? PTHREAD_STACK_MIN

                                                   : THREAD_STACK_MIN;

#else

    tss_min = THREAD_STACK_MIN;

#endif

    if (size >= tss_min) {

        /* validate stack size by setting thread attribute */

        if (pthread_attr_init(&attrs) == 0) {

            rc = pthread_attr_setstacksize(&attrs, size);

            pthread_attr_destroy(&attrs);

            if (rc == 0) {

                _PyInterpreterState_GET()->threads.stacksize = size;

                return 0;

            }

        }

    }

    return -1;

#else

    return -2;

#endif

}

#define THREAD_SET_STACKSIZE(x) _pythread_pthread_set_stacksize(x)

/* Thread Local Storage (TLS) API

   This API is DEPRECATED since Python 3.7.  See PEP 539 for details.

*/

/* Issue #25658: On platforms where native TLS key is defined in a way that

   cannot be safely cast to int, PyThread_create_key returns immediately a

   failure status and other TLS functions all are no-ops.  This indicates

   clearly that the old API is not supported on platforms where it cannot be

   used reliably, and that no effort will be made to add such support.

   Note: PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT will be unnecessary after

   removing this API.

*/

int

PyThread_create_key(void)

{

#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT

    pthread_key_t key;

    int fail = pthread_key_create(&key, NULL);

    if (fail)

        return -1;

    if (key > INT_MAX) {

        /* Issue #22206: handle integer overflow */

        pthread_key_delete(key);

        errno = ENOMEM;

        return -1;

    }

    return (int)key;

#else

    return -1;  /* never return valid key value. */

#endif

}

void

PyThread_delete_key(int key)

{

#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT

    pthread_key_delete(key);

#endif

}

void

PyThread_delete_key_value(int key)

{

#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT

    pthread_setspecific(key, NULL);

#endif

}

int

PyThread_set_key_value(int key, void *value)

{

#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT

    int fail = pthread_setspecific(key, value);

    return fail ? -1 : 0;

#else

    return -1;

#endif

}

void *

PyThread_get_key_value(int key)

{

#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT

    return pthread_getspecific(key);

#else

    return NULL;

#endif

}

void

PyThread_ReInitTLS(void)

{

}

/* Thread Specific Storage (TSS) API

   Platform-specific components of TSS API implementation.

*/

int

PyThread_tss_create(Py_tss_t *key)

{

    assert(key != NULL);

    /* If the key has been created, function is silently skipped. */

    if (key->_is_initialized) {

        return 0;

    }

    int fail = pthread_key_create(&(key->_key), NULL);

    if (fail) {

        return -1;

    }

    key->_is_initialized = 1;

    return 0;

}

void

PyThread_tss_delete(Py_tss_t *key)

{

    assert(key != NULL);

    /* If the key has not been created, function is silently skipped. */

    if (!key->_is_initialized) {

        return;

    }

    pthread_key_delete(key->_key);

    /* pthread has not provided the defined invalid value for the key. */

    key->_is_initialized = 0;

}

int

PyThread_tss_set(Py_tss_t *key, void *value)

{

    assert(key != NULL);

    int fail = pthread_setspecific(key->_key, value);

    return fail ? -1 : 0;

}

void *

PyThread_tss_get(Py_tss_t *key)

{

    assert(key != NULL);

    return pthread_getspecific(key->_key);

}