mirror of
https://github.com/mpv-player/mpv
synced 2024-12-22 23:02:37 +00:00
0bfeba2d9a
As pointed out by uau on IRC, the pointer to info is still used outside of the lock. An extremely small race condition window, but still a race condition.
341 lines
9.2 KiB
C
341 lines
9.2 KiB
C
/* Copyright (C) 2017 the mpv developers
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <pthread.h>
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#include <semaphore.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <errno.h>
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#include <sys/time.h>
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#include <assert.h>
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int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
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{
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BOOL pending;
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if (!InitOnceBeginInitialize(once_control, 0, &pending, NULL))
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abort();
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if (pending) {
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init_routine();
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InitOnceComplete(once_control, 0, NULL);
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}
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return 0;
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}
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int pthread_mutex_destroy(pthread_mutex_t *mutex)
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{
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if (mutex->use_cs)
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DeleteCriticalSection(&mutex->lock.cs);
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return 0;
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}
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int pthread_mutex_init(pthread_mutex_t *restrict mutex,
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const pthread_mutexattr_t *restrict attr)
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{
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mutex->use_cs = attr && (*attr & PTHREAD_MUTEX_RECURSIVE);
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if (mutex->use_cs) {
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InitializeCriticalSection(&mutex->lock.cs);
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} else {
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InitializeSRWLock(&mutex->lock.srw);
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}
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return 0;
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}
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int pthread_mutex_lock(pthread_mutex_t *mutex)
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{
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if (mutex->use_cs) {
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EnterCriticalSection(&mutex->lock.cs);
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} else {
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AcquireSRWLockExclusive(&mutex->lock.srw);
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}
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return 0;
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}
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int pthread_mutex_unlock(pthread_mutex_t *mutex)
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{
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if (mutex->use_cs) {
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LeaveCriticalSection(&mutex->lock.cs);
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} else {
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ReleaseSRWLockExclusive(&mutex->lock.srw);
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}
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return 0;
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}
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static int cond_wait(pthread_cond_t *restrict cond,
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pthread_mutex_t *restrict mutex,
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DWORD ms)
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{
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BOOL res;
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if (mutex->use_cs) {
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res = SleepConditionVariableCS(cond, &mutex->lock.cs, ms);
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} else {
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res = SleepConditionVariableSRW(cond, &mutex->lock.srw, ms, 0);
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}
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return res ? 0 : ETIMEDOUT;
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}
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int pthread_cond_timedwait(pthread_cond_t *restrict cond,
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pthread_mutex_t *restrict mutex,
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const struct timespec *restrict abstime)
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{
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// mpv uses mingw's gettimeofday() as time source too.
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struct timeval tv;
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gettimeofday(&tv, NULL);
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DWORD timeout_ms = 0;
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if (abstime->tv_sec >= INT64_MAX / 10000) {
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timeout_ms = INFINITE;
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} else if (abstime->tv_sec >= tv.tv_sec) {
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long long msec = (abstime->tv_sec - tv.tv_sec) * 1000LL +
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abstime->tv_nsec / 1000LL / 1000LL - tv.tv_usec / 1000LL;
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if (msec > INT_MAX) {
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timeout_ms = INFINITE;
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} else if (msec > 0) {
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timeout_ms = msec;
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}
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}
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return cond_wait(cond, mutex, timeout_ms);
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}
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int pthread_cond_wait(pthread_cond_t *restrict cond,
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pthread_mutex_t *restrict mutex)
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{
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return cond_wait(cond, mutex, INFINITE);
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}
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static pthread_mutex_t pthread_table_lock = PTHREAD_MUTEX_INITIALIZER;
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static struct m_thread_info *pthread_table;
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size_t pthread_table_num;
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struct m_thread_info {
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DWORD id;
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HANDLE handle;
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void *(*user_fn)(void *);
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void *user_arg;
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void *res;
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};
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static struct m_thread_info *find_thread_info(DWORD id)
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{
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for (int n = 0; n < pthread_table_num; n++) {
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if (id == pthread_table[n].id)
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return &pthread_table[n];
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}
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return NULL;
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}
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static void remove_thread_info(struct m_thread_info *info)
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{
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assert(pthread_table_num);
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assert(info >= &pthread_table[0] && info < &pthread_table[pthread_table_num]);
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pthread_table[info - pthread_table] = pthread_table[pthread_table_num - 1];
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pthread_table_num -= 1;
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// Avoid upsetting leak detectors.
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if (pthread_table_num == 0) {
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free(pthread_table);
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pthread_table = NULL;
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}
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}
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void pthread_exit(void *retval)
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{
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pthread_mutex_lock(&pthread_table_lock);
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struct m_thread_info *info = find_thread_info(pthread_self());
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assert(info); // not started with pthread_create, or pthread_join() race
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info->res = retval;
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if (!info->handle)
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remove_thread_info(info); // detached case
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pthread_mutex_unlock(&pthread_table_lock);
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ExitThread(0);
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}
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int pthread_join(pthread_t thread, void **retval)
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{
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pthread_mutex_lock(&pthread_table_lock);
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struct m_thread_info *info = find_thread_info(thread);
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assert(info); // not started with pthread_create, or pthread_join() race
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HANDLE h = info->handle;
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assert(h); // thread was detached
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pthread_mutex_unlock(&pthread_table_lock);
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WaitForSingleObject(h, INFINITE);
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pthread_mutex_lock(&pthread_table_lock);
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info = find_thread_info(thread);
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assert(info);
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assert(info->handle == h);
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CloseHandle(h);
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if (retval)
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*retval = info->res;
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remove_thread_info(info);
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pthread_mutex_unlock(&pthread_table_lock);
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return 0;
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}
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int pthread_detach(pthread_t thread)
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{
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if (!pthread_equal(thread, pthread_self()))
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abort(); // restriction of this wrapper
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pthread_mutex_lock(&pthread_table_lock);
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struct m_thread_info *info = find_thread_info(thread);
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assert(info); // not started with pthread_create
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assert(info->handle); // already detached
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CloseHandle(info->handle);
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info->handle = NULL;
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pthread_mutex_unlock(&pthread_table_lock);
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return 0;
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}
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static DWORD WINAPI run_thread(LPVOID lpParameter)
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{
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pthread_mutex_lock(&pthread_table_lock);
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struct m_thread_info *pinfo = find_thread_info(pthread_self());
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assert(pinfo);
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struct m_thread_info info = *pinfo;
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pthread_mutex_unlock(&pthread_table_lock);
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pthread_exit(info.user_fn(info.user_arg));
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abort(); // not reached
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}
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int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
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void *(*start_routine) (void *), void *arg)
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{
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int res = 0;
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pthread_mutex_lock(&pthread_table_lock);
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void *nalloc =
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realloc(pthread_table, (pthread_table_num + 1) * sizeof(pthread_table[0]));
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if (!nalloc) {
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res = EAGAIN;
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goto done;
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}
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pthread_table = nalloc;
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pthread_table_num += 1;
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struct m_thread_info *info = &pthread_table[pthread_table_num - 1];
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*info = (struct m_thread_info) {
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.user_fn = start_routine,
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.user_arg = arg,
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};
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info->handle = CreateThread(NULL, 0, run_thread, NULL, CREATE_SUSPENDED,
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&info->id);
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if (!info->handle) {
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remove_thread_info(info);
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res = EAGAIN;
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goto done;
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}
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*thread = info->id;
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ResumeThread(info->handle);
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done:
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pthread_mutex_unlock(&pthread_table_lock);
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return res;
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}
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void pthread_set_name_np(pthread_t thread, const char *name)
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{
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#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP) && defined(_PROCESSTHREADSAPI_H_)
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HMODULE kernel32 = GetModuleHandleW(L"kernel32.dll");
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if (!kernel32)
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return;
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HRESULT (WINAPI *pSetThreadDescription)(HANDLE, PCWSTR) =
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(void*)GetProcAddress(kernel32, "SetThreadDescription");
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if (!pSetThreadDescription)
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return;
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HANDLE th = OpenThread(THREAD_SET_LIMITED_INFORMATION, FALSE, thread);
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if (!th)
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return;
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wchar_t wname[80];
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int wc = MultiByteToWideChar(CP_UTF8, 0, name, -1, wname,
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sizeof(wname) / sizeof(wchar_t) - 1);
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if (wc > 0) {
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wname[wc] = L'\0';
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pSetThreadDescription(th, wname);
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}
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CloseHandle(th);
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#endif
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}
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int sem_init(sem_t *sem, int pshared, unsigned int value)
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{
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if (pshared)
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abort(); // unsupported
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pthread_mutex_init(&sem->lock, NULL);
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pthread_cond_init(&sem->wakeup, NULL);
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sem->value = value;
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return 0;
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}
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int sem_destroy(sem_t *sem)
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{
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pthread_mutex_destroy(&sem->lock);
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pthread_cond_destroy(&sem->wakeup);
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return 0;
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}
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int sem_wait(sem_t *sem)
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{
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pthread_mutex_lock(&sem->lock);
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while (!sem->value)
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pthread_cond_wait(&sem->wakeup, &sem->lock);
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sem->value -= 1;
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pthread_mutex_unlock(&sem->lock);
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return 0;
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}
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int sem_trywait(sem_t *sem)
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{
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pthread_mutex_lock(&sem->lock);
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int r;
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if (sem->value > 0) {
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sem->value -= 1;
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r = 0;
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} else {
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errno = EAGAIN;
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r = -1;
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}
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pthread_mutex_unlock(&sem->lock);
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return r;
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}
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int sem_timedwait(sem_t *sem, const struct timespec *abs_timeout)
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{
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pthread_mutex_lock(&sem->lock);
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while (!sem->value) {
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int err = pthread_cond_timedwait(&sem->wakeup, &sem->lock, abs_timeout);
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if (err) {
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pthread_mutex_unlock(&sem->lock);
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errno = err;
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return -1;
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}
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}
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sem->value -= 1;
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pthread_mutex_unlock(&sem->lock);
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return 0;
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}
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int sem_post(sem_t *sem)
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{
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pthread_mutex_lock(&sem->lock);
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sem->value += 1;
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pthread_cond_broadcast(&sem->wakeup);
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pthread_mutex_unlock(&sem->lock);
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return 0;
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}
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