1 /*****************************************************************************
2 * threads.c : threads implementation for the VideoLAN client
3 *****************************************************************************
4 * Copyright (C) 1999-2008 the VideoLAN team
7 * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
8 * Samuel Hocevar <sam@zoy.org>
9 * Gildas Bazin <gbazin@netcourrier.com>
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
26 *****************************************************************************/
32 #include <vlc_common.h>
42 #if defined( LIBVLC_USE_PTHREAD )
45 # include <sys/syscall.h> /* SYS_gettid */
48 static vlc_threadvar_t cancel_key;
51 #ifdef HAVE_EXECINFO_H
52 # include <execinfo.h>
56 # include <sys/time.h> /* gettimeofday in vlc_cond_timedwait */
60 * Print a backtrace to the standard error for debugging purpose.
62 void vlc_trace (const char *fn, const char *file, unsigned line)
64 fprintf (stderr, "at %s:%u in %s\n", file, line, fn);
65 fflush (stderr); /* needed before switch to low-level I/O */
68 int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
69 backtrace_symbols_fd (stack, len, 2);
76 static inline unsigned long vlc_threadid (void)
78 #if defined (LIBVLC_USE_PTHREAD)
79 # if defined (__linux__)
80 return syscall (SYS_gettid);
83 union { pthread_t th; unsigned long int i; } v = { };
84 v.th = pthread_self ();
89 return GetCurrentThreadId ();
98 /*****************************************************************************
99 * vlc_thread_fatal: Report an error from the threading layer
100 *****************************************************************************
101 * This is mostly meant for debugging.
102 *****************************************************************************/
104 vlc_thread_fatal (const char *action, int error,
105 const char *function, const char *file, unsigned line)
107 fprintf (stderr, "LibVLC fatal error %s (%d) in thread %lu ",
108 action, error, vlc_threadid ());
109 vlc_trace (function, file, line);
111 /* Sometimes strerror_r() crashes too, so make sure we print an error
112 * message before we invoke it */
114 /* Avoid the strerror_r() prototype brain damage in glibc */
116 fprintf (stderr, " Error message: %m\n");
117 #elif !defined (WIN32)
121 switch (strerror_r (error, buf, sizeof (buf)))
126 case ERANGE: /* should never happen */
127 msg = "unknwon (too big to display)";
130 msg = "unknown (invalid error number)";
133 fprintf (stderr, " Error message: %s\n", msg);
140 # define VLC_THREAD_ASSERT( action ) \
141 if (val) vlc_thread_fatal (action, val, __func__, __FILE__, __LINE__)
143 # define VLC_THREAD_ASSERT( action ) ((void)val)
147 * Per-thread cancellation data
149 #ifndef LIBVLC_USE_PTHREAD_CANCEL
150 typedef struct vlc_cancel_t
152 vlc_cleanup_t *cleaners;
161 # define VLC_CANCEL_INIT { NULL, true, false }
163 # define VLC_CANCEL_INIT { NULL, true, false, NULL }
168 static void CALLBACK vlc_cancel_self (ULONG_PTR dummy);
170 static DWORD vlc_cancelable_wait (DWORD count, const HANDLE *handles,
173 vlc_cancel_t *nfo = vlc_threadvar_get (cancel_key);
176 /* Main thread - cannot be cancelled anyway */
177 return WaitForMultipleObjects (count, handles, FALSE, delay);
179 HANDLE new_handles[count + 1];
180 memcpy(new_handles, handles, count * sizeof(HANDLE));
181 new_handles[count] = nfo->cancel_event;
182 DWORD result = WaitForMultipleObjects (count + 1, new_handles, FALSE,
184 if (result == WAIT_OBJECT_0 + count)
186 vlc_cancel_self (NULL);
187 return WAIT_IO_COMPLETION;
195 DWORD SleepEx (DWORD dwMilliseconds, BOOL bAlertable)
199 DWORD result = vlc_cancelable_wait (0, NULL, dwMilliseconds);
200 return (result == WAIT_TIMEOUT) ? 0 : WAIT_IO_COMPLETION;
204 Sleep(dwMilliseconds);
209 DWORD WaitForSingleObjectEx (HANDLE hHandle, DWORD dwMilliseconds,
214 /* The MSDN documentation specifies different return codes,
215 * but in practice they are the same. We just check that it
217 #if WAIT_ABANDONED != WAIT_ABANDONED_0
218 # error Windows headers changed, code needs to be rewritten!
220 return vlc_cancelable_wait (1, &hHandle, dwMilliseconds);
224 return WaitForSingleObject (hHandle, dwMilliseconds);
228 DWORD WaitForMultipleObjectsEx (DWORD nCount, const HANDLE *lpHandles,
229 BOOL bWaitAll, DWORD dwMilliseconds,
234 /* We do not support the bWaitAll case */
236 return vlc_cancelable_wait (nCount, lpHandles, dwMilliseconds);
240 return WaitForMultipleObjects (nCount, lpHandles, bWaitAll,
247 static vlc_mutex_t super_mutex, tls_mutex;
248 static struct vlc_threadvar *tls_list = NULL;
250 BOOL WINAPI DllMain (HINSTANCE hinstDll, DWORD fdwReason, LPVOID lpvReserved)
257 case DLL_PROCESS_ATTACH:
258 vlc_mutex_init (&super_mutex);
259 vlc_mutex_init (&tls_mutex);
260 vlc_threadvar_create (&cancel_key, free);
263 case DLL_PROCESS_DETACH:
264 vlc_threadvar_delete( &cancel_key );
265 assert (tls_list == NULL);
266 vlc_mutex_destroy (&tls_mutex);
267 vlc_mutex_destroy (&super_mutex);
274 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
275 /* This is not prototyped under glibc, though it exists. */
276 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
279 /*****************************************************************************
280 * vlc_mutex_init: initialize a mutex
281 *****************************************************************************/
282 int vlc_mutex_init( vlc_mutex_t *p_mutex )
284 #if defined( LIBVLC_USE_PTHREAD )
285 pthread_mutexattr_t attr;
288 pthread_mutexattr_init( &attr );
291 /* Create error-checking mutex to detect problems more easily. */
292 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
293 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
295 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
298 i_result = pthread_mutex_init( p_mutex, &attr );
299 pthread_mutexattr_destroy( &attr );
302 #elif defined( WIN32 )
303 /* This creates a recursive mutex. This is OK as fast mutexes have
304 * no defined behavior in case of recursive locking. */
305 InitializeCriticalSection (&p_mutex->mutex);
306 p_mutex->initialized = 1;
312 /*****************************************************************************
313 * vlc_mutex_init: initialize a recursive mutex (Do not use)
314 *****************************************************************************/
315 int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
317 #if defined( LIBVLC_USE_PTHREAD )
318 pthread_mutexattr_t attr;
321 pthread_mutexattr_init( &attr );
322 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
323 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
325 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
327 i_result = pthread_mutex_init( p_mutex, &attr );
328 pthread_mutexattr_destroy( &attr );
331 #elif defined( WIN32 )
332 InitializeCriticalSection( &p_mutex->mutex );
333 p_mutex->initialized = 1;
341 * Destroys a mutex. The mutex must not be locked.
343 * @param p_mutex mutex to destroy
344 * @return always succeeds
346 void vlc_mutex_destroy (vlc_mutex_t *p_mutex)
348 #if defined( LIBVLC_USE_PTHREAD )
349 int val = pthread_mutex_destroy( p_mutex );
350 VLC_THREAD_ASSERT ("destroying mutex");
352 #elif defined( WIN32 )
353 assert (InterlockedExchange (&p_mutex->initialized, -1) == 1);
354 DeleteCriticalSection (&p_mutex->mutex);
360 * Acquires a mutex. If needed, waits for any other thread to release it.
361 * Beware of deadlocks when locking multiple mutexes at the same time,
362 * or when using mutexes from callbacks.
363 * This function is not a cancellation-point.
365 * @param p_mutex mutex initialized with vlc_mutex_init() or
366 * vlc_mutex_init_recursive()
368 void vlc_mutex_lock (vlc_mutex_t *p_mutex)
370 #if defined(LIBVLC_USE_PTHREAD)
371 int val = pthread_mutex_lock( p_mutex );
372 VLC_THREAD_ASSERT ("locking mutex");
374 #elif defined( WIN32 )
375 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
376 { /* ^^ We could also lock super_mutex all the time... sluggish */
377 assert (p_mutex != &super_mutex); /* this one cannot be static */
379 vlc_mutex_lock (&super_mutex);
380 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
381 vlc_mutex_init (p_mutex);
382 /* FIXME: destroy the mutex some time... */
383 vlc_mutex_unlock (&super_mutex);
385 assert (InterlockedExchange (&p_mutex->initialized, 1) == 1);
386 EnterCriticalSection (&p_mutex->mutex);
392 * Acquires a mutex if and only if it is not currently held by another thread.
393 * This function never sleeps and can be used in delay-critical code paths.
394 * This function is not a cancellation-point.
396 * <b>Beware</b>: If this function fails, then the mutex is held... by another
397 * thread. The calling thread must deal with the error appropriately. That
398 * typically implies postponing the operations that would have required the
399 * mutex. If the thread cannot defer those operations, then it must use
400 * vlc_mutex_lock(). If in doubt, use vlc_mutex_lock() instead.
402 * @param p_mutex mutex initialized with vlc_mutex_init() or
403 * vlc_mutex_init_recursive()
404 * @return 0 if the mutex could be acquired, an error code otherwise.
406 int vlc_mutex_trylock (vlc_mutex_t *p_mutex)
408 #if defined(LIBVLC_USE_PTHREAD)
409 int val = pthread_mutex_trylock( p_mutex );
412 VLC_THREAD_ASSERT ("locking mutex");
415 #elif defined( WIN32 )
416 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
417 { /* ^^ We could also lock super_mutex all the time... sluggish */
418 assert (p_mutex != &super_mutex); /* this one cannot be static */
420 vlc_mutex_lock (&super_mutex);
421 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
422 vlc_mutex_init (p_mutex);
423 /* FIXME: destroy the mutex some time... */
424 vlc_mutex_unlock (&super_mutex);
426 assert (InterlockedExchange (&p_mutex->initialized, 1) == 1);
427 return TryEnterCriticalSection (&p_mutex->mutex) ? 0 : EBUSY;
433 * Releases a mutex (or crashes if the mutex is not locked by the caller).
434 * @param p_mutex mutex locked with vlc_mutex_lock().
436 void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
438 #if defined(LIBVLC_USE_PTHREAD)
439 int val = pthread_mutex_unlock( p_mutex );
440 VLC_THREAD_ASSERT ("unlocking mutex");
442 #elif defined( WIN32 )
443 assert (InterlockedExchange (&p_mutex->initialized, 1) == 1);
444 LeaveCriticalSection (&p_mutex->mutex);
449 /*****************************************************************************
450 * vlc_cond_init: initialize a condition variable
451 *****************************************************************************/
452 int vlc_cond_init( vlc_cond_t *p_condvar )
454 #if defined( LIBVLC_USE_PTHREAD )
455 pthread_condattr_t attr;
458 ret = pthread_condattr_init (&attr);
462 # if !defined (_POSIX_CLOCK_SELECTION)
463 /* Fairly outdated POSIX support (that was defined in 2001) */
464 # define _POSIX_CLOCK_SELECTION (-1)
466 # if (_POSIX_CLOCK_SELECTION >= 0)
467 /* NOTE: This must be the same clock as the one in mtime.c */
468 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
471 ret = pthread_cond_init (p_condvar, &attr);
472 pthread_condattr_destroy (&attr);
475 #elif defined( WIN32 )
476 /* Create a manual-reset event (manual reset is needed for broadcast). */
477 *p_condvar = CreateEvent( NULL, TRUE, FALSE, NULL );
478 return *p_condvar ? 0 : ENOMEM;
484 * Destroys a condition variable. No threads shall be waiting or signaling the
486 * @param p_condvar condition variable to destroy
488 void vlc_cond_destroy (vlc_cond_t *p_condvar)
490 #if defined( LIBVLC_USE_PTHREAD )
491 int val = pthread_cond_destroy( p_condvar );
492 VLC_THREAD_ASSERT ("destroying condition");
494 #elif defined( WIN32 )
495 CloseHandle( *p_condvar );
501 * Wakes up one thread waiting on a condition variable, if any.
502 * @param p_condvar condition variable
504 void vlc_cond_signal (vlc_cond_t *p_condvar)
506 #if defined(LIBVLC_USE_PTHREAD)
507 int val = pthread_cond_signal( p_condvar );
508 VLC_THREAD_ASSERT ("signaling condition variable");
510 #elif defined( WIN32 )
511 /* NOTE: This will cause a broadcast, that is wrong.
512 * This will also wake up the next waiting thread if no thread are yet
513 * waiting, which is also wrong. However both of these issues are allowed
514 * by the provision for spurious wakeups. Better have too many wakeups
515 * than too few (= deadlocks). */
516 SetEvent (*p_condvar);
522 * Wakes up all threads (if any) waiting on a condition variable.
523 * @param p_cond condition variable
525 void vlc_cond_broadcast (vlc_cond_t *p_condvar)
527 #if defined (LIBVLC_USE_PTHREAD)
528 pthread_cond_broadcast (p_condvar);
530 #elif defined (WIN32)
531 SetEvent (*p_condvar);
537 * Waits for a condition variable. The calling thread will be suspended until
538 * another thread calls vlc_cond_signal() or vlc_cond_broadcast() on the same
539 * condition variable, the thread is cancelled with vlc_cancel(), or the
540 * system causes a "spurious" unsolicited wake-up.
542 * A mutex is needed to wait on a condition variable. It must <b>not</b> be
543 * a recursive mutex. Although it is possible to use the same mutex for
544 * multiple condition, it is not valid to use different mutexes for the same
545 * condition variable at the same time from different threads.
547 * In case of thread cancellation, the mutex is always locked before
548 * cancellation proceeds.
550 * The canonical way to use a condition variable to wait for event foobar is:
552 vlc_mutex_lock (&lock);
553 mutex_cleanup_push (&lock); // release the mutex in case of cancellation
556 vlc_cond_wait (&wait, &lock);
558 --- foobar is now true, do something about it here --
560 vlc_cleanup_run (); // release the mutex
563 * @param p_condvar condition variable to wait on
564 * @param p_mutex mutex which is unlocked while waiting,
565 * then locked again when waking up.
566 * @param deadline <b>absolute</b> timeout
568 * @return 0 if the condition was signaled, an error code in case of timeout.
570 void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
572 #if defined(LIBVLC_USE_PTHREAD)
573 int val = pthread_cond_wait( p_condvar, p_mutex );
574 VLC_THREAD_ASSERT ("waiting on condition");
576 #elif defined( WIN32 )
582 LeaveCriticalSection (&p_mutex->mutex);
583 result = WaitForSingleObjectEx (*p_condvar, INFINITE, TRUE);
584 EnterCriticalSection (&p_mutex->mutex);
586 while (result == WAIT_IO_COMPLETION);
588 ResetEvent (*p_condvar);
594 * Waits for a condition variable up to a certain date.
595 * This works like vlc_cond_wait(), except for the additional timeout.
597 * @param p_condvar condition variable to wait on
598 * @param p_mutex mutex which is unlocked while waiting,
599 * then locked again when waking up.
600 * @param deadline <b>absolute</b> timeout
602 * @return 0 if the condition was signaled, an error code in case of timeout.
604 int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
607 #if defined(LIBVLC_USE_PTHREAD)
609 /* mdate() is mac_absolute_time on osx, which we must convert to do
610 * the same base than gettimeofday() on which pthread_cond_timedwait
612 mtime_t oldbase = mdate();
614 gettimeofday(&tv, NULL);
615 mtime_t newbase = (mtime_t)tv.tv_sec * 1000000 + (mtime_t) tv.tv_usec;
616 deadline = deadline - oldbase + newbase;
618 lldiv_t d = lldiv( deadline, CLOCK_FREQ );
619 struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
621 int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
622 if (val != ETIMEDOUT)
623 VLC_THREAD_ASSERT ("timed-waiting on condition");
626 #elif defined( WIN32 )
633 mtime_t total = (deadline - mdate ())/1000;
637 DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
638 LeaveCriticalSection (&p_mutex->mutex);
639 result = WaitForSingleObjectEx (*p_condvar, delay, TRUE);
640 EnterCriticalSection (&p_mutex->mutex);
642 while (result == WAIT_IO_COMPLETION);
644 ResetEvent (*p_condvar);
646 return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
652 #if defined (LIBVLC_USE_PTHREAD)
653 #elif defined (WIN32)
657 void (*cleanup) (void *);
658 struct vlc_threadvar *prev, *next;
661 static void vlc_threadvar_cleanup (void)
663 struct vlc_threadvar *p;
665 vlc_mutex_lock (&tls_mutex);
666 for (p = tls_list; p != NULL; p = p->next)
668 void *value = TlsGetValue (p->handle);
672 vlc_mutex_unlock (&tls_mutex);
676 /*****************************************************************************
677 * vlc_tls_create: create a thread-local variable
678 *****************************************************************************/
679 int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
681 #if defined( LIBVLC_USE_PTHREAD )
682 return pthread_key_create( p_tls, destr );
684 #elif defined( WIN32 )
685 struct vlc_threadvar *tls = malloc (sizeof (*tls));
689 tls->handle = TlsAlloc();
690 if (tls->handle == TLS_OUT_OF_INDEXES)
695 tls->cleanup = destr;
697 vlc_mutex_lock (&tls_mutex);
698 tls->next = tls_list;
700 tls_list->prev = tls;
702 vlc_mutex_unlock (&tls_mutex);
707 # error Unimplemented!
711 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
713 #if defined( LIBVLC_USE_PTHREAD )
714 pthread_key_delete (*p_tls);
716 #elif defined( WIN32 )
717 struct vlc_threadvar *tls = *p_tls;
719 TlsFree (tls->handle);
720 vlc_mutex_lock (&tls_mutex);
722 tls->prev->next = tls->next;
724 tls->next->prev = tls->prev;
725 vlc_mutex_unlock (&tls_mutex);
729 # error Unimplemented!
734 * Sets a thread-local variable.
735 * @param key thread-local variable key (created with vlc_threadvar_create())
736 * @param value new value for the variable for the calling thread
737 * @return 0 on success, a system error code otherwise.
739 int vlc_threadvar_set (vlc_threadvar_t key, void *value)
741 #if defined(LIBVLC_USE_PTHREAD)
742 return pthread_setspecific (key, value);
743 #elif defined( UNDER_CE ) || defined( WIN32 )
744 return TlsSetValue (key->handle, value) ? ENOMEM : 0;
746 # error Unimplemented!
751 * Gets the value of a thread-local variable for the calling thread.
752 * This function cannot fail.
753 * @return the value associated with the given variable for the calling
754 * or NULL if there is no value.
756 void *vlc_threadvar_get (vlc_threadvar_t key)
758 #if defined(LIBVLC_USE_PTHREAD)
759 return pthread_getspecific (key);
760 #elif defined( UNDER_CE ) || defined( WIN32 )
761 return TlsGetValue (key->handle);
763 # error Unimplemented!
767 #if defined (LIBVLC_USE_PTHREAD)
768 #elif defined (WIN32)
769 static unsigned __stdcall vlc_entry (void *data)
771 vlc_cancel_t cancel_data = VLC_CANCEL_INIT;
772 vlc_thread_t self = data;
774 cancel_data.cancel_event = self->cancel_event;
777 vlc_threadvar_set (cancel_key, &cancel_data);
778 self->data = self->entry (self->data);
779 vlc_threadvar_cleanup ();
785 * Creates and starts new thread.
787 * @param p_handle [OUT] pointer to write the handle of the created thread to
788 * @param entry entry point for the thread
789 * @param data data parameter given to the entry point
790 * @param priority thread priority value
791 * @return 0 on success, a standard error code on error.
793 int vlc_clone (vlc_thread_t *p_handle, void * (*entry) (void *), void *data,
798 #if defined( LIBVLC_USE_PTHREAD )
800 pthread_attr_init (&attr);
802 /* Block the signals that signals interface plugin handles.
803 * If the LibVLC caller wants to handle some signals by itself, it should
804 * block these before whenever invoking LibVLC. And it must obviously not
805 * start the VLC signals interface plugin.
807 * LibVLC will normally ignore any interruption caused by an asynchronous
808 * signal during a system call. But there may well be some buggy cases
809 * where it fails to handle EINTR (bug reports welcome). Some underlying
810 * libraries might also not handle EINTR properly.
816 sigdelset (&set, SIGHUP);
817 sigaddset (&set, SIGINT);
818 sigaddset (&set, SIGQUIT);
819 sigaddset (&set, SIGTERM);
821 sigaddset (&set, SIGPIPE); /* We don't want this one, really! */
822 pthread_sigmask (SIG_BLOCK, &set, &oldset);
825 struct sched_param sp = { .sched_priority = priority, };
828 if (sp.sched_priority <= 0)
829 sp.sched_priority += sched_get_priority_max (policy = SCHED_OTHER);
831 sp.sched_priority += sched_get_priority_min (policy = SCHED_RR);
833 pthread_attr_setschedpolicy (&attr, policy);
834 pthread_attr_setschedparam (&attr, &sp);
837 /* The thread stack size.
838 * The lower the value, the less address space per thread, the highest
839 * maximum simultaneous threads per process. Too low values will cause
840 * stack overflows and weird crashes. Set with caution. Also keep in mind
841 * that 64-bits platforms consume more stack than 32-bits one.
843 * Thanks to on-demand paging, thread stack size only affects address space
844 * consumption. In terms of memory, threads only use what they need
845 * (rounded up to the page boundary).
847 * For example, on Linux i386, the default is 2 mega-bytes, which supports
848 * about 320 threads per processes. */
849 #define VLC_STACKSIZE (128 * sizeof (void *) * 1024)
852 ret = pthread_attr_setstacksize (&attr, VLC_STACKSIZE);
853 assert (ret == 0); /* fails iif VLC_STACKSIZE is invalid */
856 ret = pthread_create (p_handle, &attr, entry, data);
857 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
858 pthread_attr_destroy (&attr);
860 #elif defined( WIN32 ) || defined( UNDER_CE )
861 /* When using the MSVCRT C library you have to use the _beginthreadex
862 * function instead of CreateThread, otherwise you'll end up with
863 * memory leaks and the signal functions not working (see Microsoft
864 * Knowledge Base, article 104641) */
866 vlc_thread_t th = malloc (sizeof (*th));
873 #if defined( UNDER_CE )
874 th->cancel_event = CreateEvent (NULL, FALSE, FALSE, NULL);
875 if (th->cancel_event == NULL)
880 hThread = CreateThread (NULL, 128*1024, vlc_entry, th, CREATE_SUSPENDED, NULL);
882 hThread = (HANDLE)(uintptr_t)
883 _beginthreadex (NULL, 0, vlc_entry, th, CREATE_SUSPENDED, NULL);
889 /* Thread closes the handle when exiting, duplicate it here
890 * to be on the safe side when joining. */
891 if (!DuplicateHandle (GetCurrentProcess (), hThread,
892 GetCurrentProcess (), &th->handle, 0, FALSE,
893 DUPLICATE_SAME_ACCESS))
895 CloseHandle (hThread);
900 th->handle = hThread;
903 ResumeThread (hThread);
905 SetThreadPriority (hThread, priority);
921 /* APC procedure for thread cancellation */
922 static void CALLBACK vlc_cancel_self (ULONG_PTR dummy)
925 vlc_control_cancel (VLC_DO_CANCEL);
930 * Marks a thread as cancelled. Next time the target thread reaches a
931 * cancellation point (while not having disabled cancellation), it will
932 * run its cancellation cleanup handler, the thread variable destructors, and
933 * terminate. vlc_join() must be used afterward regardless of a thread being
936 void vlc_cancel (vlc_thread_t thread_id)
938 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
939 pthread_cancel (thread_id);
940 #elif defined (UNDER_CE)
941 SetEvent (thread_id->cancel_event);
942 #elif defined (WIN32)
943 QueueUserAPC (vlc_cancel_self, thread_id->handle, 0);
945 # warning vlc_cancel is not implemented!
950 * Waits for a thread to complete (if needed), and destroys it.
951 * This is a cancellation point; in case of cancellation, the join does _not_
954 * @param handle thread handle
955 * @param p_result [OUT] pointer to write the thread return value or NULL
956 * @return 0 on success, a standard error code otherwise.
958 void vlc_join (vlc_thread_t handle, void **result)
960 #if defined( LIBVLC_USE_PTHREAD )
961 int val = pthread_join (handle, result);
962 VLC_THREAD_ASSERT ("joining thread");
964 #elif defined( UNDER_CE ) || defined( WIN32 )
967 while (WaitForSingleObjectEx (handle->handle, INFINITE, TRUE)
968 == WAIT_IO_COMPLETION);
970 CloseHandle (handle->handle);
972 *result = handle->data;
973 #if defined( UNDER_CE )
974 CloseHandle (handle->cancel_event);
982 * Save the current cancellation state (enabled or disabled), then disable
983 * cancellation for the calling thread.
984 * This function must be called before entering a piece of code that is not
985 * cancellation-safe, unless it can be proven that the calling thread will not
987 * @return Previous cancellation state (opaque value for vlc_restorecancel()).
989 int vlc_savecancel (void)
993 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
994 int val = pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
995 VLC_THREAD_ASSERT ("saving cancellation");
998 vlc_cancel_t *nfo = vlc_threadvar_get (cancel_key);
1000 return false; /* Main thread - cannot be cancelled anyway */
1002 state = nfo->killable;
1003 nfo->killable = false;
1010 * Restore the cancellation state for the calling thread.
1011 * @param state previous state as returned by vlc_savecancel().
1012 * @return Nothing, always succeeds.
1014 void vlc_restorecancel (int state)
1016 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
1020 val = pthread_setcancelstate (state, &oldstate);
1021 /* This should fail if an invalid value for given for state */
1022 VLC_THREAD_ASSERT ("restoring cancellation");
1024 if (oldstate != PTHREAD_CANCEL_DISABLE)
1025 vlc_thread_fatal ("restoring cancellation while not disabled", EINVAL,
1026 __func__, __FILE__, __LINE__);
1028 pthread_setcancelstate (state, NULL);
1032 vlc_cancel_t *nfo = vlc_threadvar_get (cancel_key);
1033 assert (state == false || state == true);
1036 return; /* Main thread - cannot be cancelled anyway */
1038 assert (!nfo->killable);
1039 nfo->killable = state != 0;
1045 * Issues an explicit deferred cancellation point.
1046 * This has no effect if thread cancellation is disabled.
1047 * This can be called when there is a rather slow non-sleeping operation.
1048 * This is also used to force a cancellation point in a function that would
1049 * otherwise "not always" be a one (block_FifoGet() is an example).
1051 void vlc_testcancel (void)
1053 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
1054 pthread_testcancel ();
1057 vlc_cancel_t *nfo = vlc_threadvar_get (cancel_key);
1059 return; /* Main thread - cannot be cancelled anyway */
1061 if (nfo->killable && nfo->killed)
1063 for (vlc_cleanup_t *p = nfo->cleaners; p != NULL; p = p->next)
1065 # if defined (LIBVLC_USE_PTHREAD)
1066 pthread_exit (PTHREAD_CANCELLED);
1067 # elif defined (UNDER_CE)
1068 vlc_threadvar_cleanup ();
1070 # elif defined (WIN32)
1071 vlc_threadvar_cleanup ();
1074 # error Not implemented!
1081 struct vlc_thread_boot
1083 void * (*entry) (vlc_object_t *);
1084 vlc_object_t *object;
1087 static void *thread_entry (void *data)
1089 vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
1090 void *(*func) (vlc_object_t *) = ((struct vlc_thread_boot *)data)->entry;
1093 msg_Dbg (obj, "thread started");
1095 msg_Dbg (obj, "thread ended");
1100 #undef vlc_thread_create
1101 /*****************************************************************************
1102 * vlc_thread_create: create a thread
1103 *****************************************************************************
1104 * Note that i_priority is only taken into account on platforms supporting
1105 * userland real-time priority threads.
1106 *****************************************************************************/
1107 int vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
1108 const char *psz_name, void *(*func) ( vlc_object_t * ),
1112 vlc_object_internals_t *p_priv = vlc_internals( p_this );
1114 struct vlc_thread_boot *boot = malloc (sizeof (*boot));
1118 boot->object = p_this;
1120 /* Make sure we don't re-create a thread if the object has already one */
1121 assert( !p_priv->b_thread );
1123 #if defined( LIBVLC_USE_PTHREAD )
1125 if( config_GetInt( p_this, "rt-priority" ) > 0 )
1128 /* Hack to avoid error msg */
1129 if( config_GetType( p_this, "rt-offset" ) )
1130 i_priority += config_GetInt( p_this, "rt-offset" );
1134 p_priv->b_thread = true;
1135 i_ret = vlc_clone( &p_priv->thread_id, thread_entry, boot, i_priority );
1137 msg_Dbg( p_this, "thread (%s) created at priority %d (%s:%d)",
1138 psz_name, i_priority, psz_file, i_line );
1141 p_priv->b_thread = false;
1143 msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
1144 psz_name, psz_file, i_line );
1150 /*****************************************************************************
1151 * vlc_thread_set_priority: set the priority of the current thread when we
1152 * couldn't set it in vlc_thread_create (for instance for the main thread)
1153 *****************************************************************************/
1154 int __vlc_thread_set_priority( vlc_object_t *p_this, const char * psz_file,
1155 int i_line, int i_priority )
1157 vlc_object_internals_t *p_priv = vlc_internals( p_this );
1159 if( !p_priv->b_thread )
1161 msg_Err( p_this, "couldn't set priority of non-existent thread" );
1165 #if defined( LIBVLC_USE_PTHREAD )
1167 if( config_GetInt( p_this, "rt-priority" ) > 0 )
1170 int i_error, i_policy;
1171 struct sched_param param;
1173 memset( ¶m, 0, sizeof(struct sched_param) );
1174 if( config_GetType( p_this, "rt-offset" ) )
1175 i_priority += config_GetInt( p_this, "rt-offset" );
1176 if( i_priority <= 0 )
1178 param.sched_priority = (-1) * i_priority;
1179 i_policy = SCHED_OTHER;
1183 param.sched_priority = i_priority;
1184 i_policy = SCHED_RR;
1186 if( (i_error = pthread_setschedparam( p_priv->thread_id,
1187 i_policy, ¶m )) )
1190 msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
1196 #elif defined( WIN32 ) || defined( UNDER_CE )
1197 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
1199 if( !SetThreadPriority(p_priv->thread_id->handle, i_priority) )
1201 msg_Warn( p_this, "couldn't set a faster priority" );
1210 /*****************************************************************************
1211 * vlc_thread_join: wait until a thread exits, inner version
1212 *****************************************************************************/
1213 void __vlc_thread_join( vlc_object_t *p_this )
1215 vlc_object_internals_t *p_priv = vlc_internals( p_this );
1217 #if defined( LIBVLC_USE_PTHREAD )
1218 vlc_join (p_priv->thread_id, NULL);
1220 #elif defined( UNDER_CE ) || defined( WIN32 )
1222 FILETIME create_ft, exit_ft, kernel_ft, user_ft;
1223 int64_t real_time, kernel_time, user_time;
1226 if( ! DuplicateHandle(GetCurrentProcess(),
1227 p_priv->thread_id->handle,
1228 GetCurrentProcess(),
1232 DUPLICATE_SAME_ACCESS) )
1234 p_priv->b_thread = false;
1235 return; /* We have a problem! */
1238 hThread = p_priv->thread_id->handle;
1241 vlc_join( p_priv->thread_id, NULL );
1243 if( GetThreadTimes( hThread, &create_ft, &exit_ft, &kernel_ft, &user_ft ) )
1246 ((((int64_t)exit_ft.dwHighDateTime)<<32)| exit_ft.dwLowDateTime) -
1247 ((((int64_t)create_ft.dwHighDateTime)<<32)| create_ft.dwLowDateTime);
1251 ((((int64_t)kernel_ft.dwHighDateTime)<<32)|
1252 kernel_ft.dwLowDateTime) / 10;
1255 ((((int64_t)user_ft.dwHighDateTime)<<32)|
1256 user_ft.dwLowDateTime) / 10;
1258 msg_Dbg( p_this, "thread times: "
1259 "real %"PRId64"m%fs, kernel %"PRId64"m%fs, user %"PRId64"m%fs",
1260 real_time/60/1000000,
1261 (double)((real_time%(60*1000000))/1000000.0),
1262 kernel_time/60/1000000,
1263 (double)((kernel_time%(60*1000000))/1000000.0),
1264 user_time/60/1000000,
1265 (double)((user_time%(60*1000000))/1000000.0) );
1267 CloseHandle( hThread );
1270 vlc_join( p_priv->thread_id, NULL );
1274 p_priv->b_thread = false;
1277 void vlc_thread_cancel (vlc_object_t *obj)
1279 vlc_object_internals_t *priv = vlc_internals (obj);
1282 vlc_cancel (priv->thread_id);
1285 void vlc_control_cancel (int cmd, ...)
1287 /* NOTE: This function only modifies thread-specific data, so there is no
1288 * need to lock anything. */
1289 #ifdef LIBVLC_USE_PTHREAD_CANCEL
1295 vlc_cancel_t *nfo = vlc_threadvar_get (cancel_key);
1299 /* Main thread - cannot be cancelled anyway */
1302 nfo = malloc (sizeof (*nfo));
1304 return; /* Uho! Expect problems! */
1305 *nfo = VLC_CANCEL_INIT;
1306 vlc_threadvar_set (cancel_key, nfo);
1317 case VLC_CLEANUP_PUSH:
1319 /* cleaner is a pointer to the caller stack, no need to allocate
1320 * and copy anything. As a nice side effect, this cannot fail. */
1321 vlc_cleanup_t *cleaner = va_arg (ap, vlc_cleanup_t *);
1322 cleaner->next = nfo->cleaners;
1323 nfo->cleaners = cleaner;
1327 case VLC_CLEANUP_POP:
1329 nfo->cleaners = nfo->cleaners->next;