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 ();
97 /*****************************************************************************
98 * vlc_thread_fatal: Report an error from the threading layer
99 *****************************************************************************
100 * This is mostly meant for debugging.
101 *****************************************************************************/
103 vlc_thread_fatal (const char *action, int error,
104 const char *function, const char *file, unsigned line)
106 fprintf (stderr, "LibVLC fatal error %s (%d) in thread %lu ",
107 action, error, vlc_threadid ());
108 vlc_trace (function, file, line);
110 /* Sometimes strerror_r() crashes too, so make sure we print an error
111 * message before we invoke it */
113 /* Avoid the strerror_r() prototype brain damage in glibc */
115 fprintf (stderr, " Error message: %m\n");
116 #elif !defined (WIN32)
120 switch (strerror_r (error, buf, sizeof (buf)))
125 case ERANGE: /* should never happen */
126 msg = "unknwon (too big to display)";
129 msg = "unknown (invalid error number)";
132 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;
249 BOOL WINAPI DllMain (HINSTANCE hinstDll, DWORD fdwReason, LPVOID lpvReserved)
256 case DLL_PROCESS_ATTACH:
257 vlc_mutex_init (&super_mutex);
258 vlc_threadvar_create (&cancel_key, free);
261 case DLL_PROCESS_DETACH:
262 vlc_threadvar_delete( &cancel_key );
263 vlc_mutex_destroy (&super_mutex);
270 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
271 /* This is not prototyped under glibc, though it exists. */
272 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
275 /*****************************************************************************
276 * vlc_mutex_init: initialize a mutex
277 *****************************************************************************/
278 int vlc_mutex_init( vlc_mutex_t *p_mutex )
280 #if defined( LIBVLC_USE_PTHREAD )
281 pthread_mutexattr_t attr;
284 pthread_mutexattr_init( &attr );
287 /* Create error-checking mutex to detect problems more easily. */
288 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
289 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
291 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
294 i_result = pthread_mutex_init( p_mutex, &attr );
295 pthread_mutexattr_destroy( &attr );
298 #elif defined( WIN32 )
299 /* This creates a recursive mutex. This is OK as fast mutexes have
300 * no defined behavior in case of recursive locking. */
301 InitializeCriticalSection (&p_mutex->mutex);
302 p_mutex->initialized = 1;
308 /*****************************************************************************
309 * vlc_mutex_init: initialize a recursive mutex (Do not use)
310 *****************************************************************************/
311 int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
313 #if defined( LIBVLC_USE_PTHREAD )
314 pthread_mutexattr_t attr;
317 pthread_mutexattr_init( &attr );
318 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
319 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
321 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
323 i_result = pthread_mutex_init( p_mutex, &attr );
324 pthread_mutexattr_destroy( &attr );
327 #elif defined( WIN32 )
328 InitializeCriticalSection( &p_mutex->mutex );
329 p_mutex->initialized = 1;
337 * Destroys a mutex. The mutex must not be locked.
339 * @param p_mutex mutex to destroy
340 * @return always succeeds
342 void vlc_mutex_destroy (vlc_mutex_t *p_mutex)
344 #if defined( LIBVLC_USE_PTHREAD )
345 int val = pthread_mutex_destroy( p_mutex );
346 VLC_THREAD_ASSERT ("destroying mutex");
348 #elif defined( WIN32 )
349 assert (InterlockedExchange (&p_mutex->initialized, -1) == 1);
350 DeleteCriticalSection (&p_mutex->mutex);
356 * Acquires a mutex. If needed, waits for any other thread to release it.
357 * Beware of deadlocks when locking multiple mutexes at the same time,
358 * or when using mutexes from callbacks.
359 * This function is not a cancellation-point.
361 * @param p_mutex mutex initialized with vlc_mutex_init() or
362 * vlc_mutex_init_recursive()
364 void vlc_mutex_lock (vlc_mutex_t *p_mutex)
366 #if defined(LIBVLC_USE_PTHREAD)
367 int val = pthread_mutex_lock( p_mutex );
368 VLC_THREAD_ASSERT ("locking mutex");
370 #elif defined( WIN32 )
371 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
372 { /* ^^ We could also lock super_mutex all the time... sluggish */
373 assert (p_mutex != &super_mutex); /* this one cannot be static */
375 vlc_mutex_lock (&super_mutex);
376 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
377 vlc_mutex_init (p_mutex);
378 /* FIXME: destroy the mutex some time... */
379 vlc_mutex_unlock (&super_mutex);
381 assert (InterlockedExchange (&p_mutex->initialized, 1) == 1);
382 EnterCriticalSection (&p_mutex->mutex);
388 * Acquires a mutex if and only if it is not currently held by another thread.
389 * This function never sleeps and can be used in delay-critical code paths.
390 * This function is not a cancellation-point.
392 * <b>Beware</b>: If this function fails, then the mutex is held... by another
393 * thread. The calling thread must deal with the error appropriately. That
394 * typically implies postponing the operations that would have required the
395 * mutex. If the thread cannot defer those operations, then it must use
396 * vlc_mutex_lock(). If in doubt, use vlc_mutex_lock() instead.
398 * @param p_mutex mutex initialized with vlc_mutex_init() or
399 * vlc_mutex_init_recursive()
400 * @return 0 if the mutex could be acquired, an error code otherwise.
402 int vlc_mutex_trylock (vlc_mutex_t *p_mutex)
404 #if defined(LIBVLC_USE_PTHREAD)
405 int val = pthread_mutex_trylock( p_mutex );
408 VLC_THREAD_ASSERT ("locking mutex");
411 #elif defined( WIN32 )
412 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
413 { /* ^^ We could also lock super_mutex all the time... sluggish */
414 assert (p_mutex != &super_mutex); /* this one cannot be static */
416 vlc_mutex_lock (&super_mutex);
417 if (InterlockedCompareExchange (&p_mutex->initialized, 0, 0) == 0)
418 vlc_mutex_init (p_mutex);
419 /* FIXME: destroy the mutex some time... */
420 vlc_mutex_unlock (&super_mutex);
422 assert (InterlockedExchange (&p_mutex->initialized, 1) == 1);
423 return TryEnterCriticalSection (&p_mutex->mutex) ? 0 : EBUSY;
429 * Releases a mutex (or crashes if the mutex is not locked by the caller).
430 * @param p_mutex mutex locked with vlc_mutex_lock().
432 void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
434 #if defined(LIBVLC_USE_PTHREAD)
435 int val = pthread_mutex_unlock( p_mutex );
436 VLC_THREAD_ASSERT ("unlocking mutex");
438 #elif defined( WIN32 )
439 assert (InterlockedExchange (&p_mutex->initialized, 1) == 1);
440 LeaveCriticalSection (&p_mutex->mutex);
445 /*****************************************************************************
446 * vlc_cond_init: initialize a condition variable
447 *****************************************************************************/
448 int vlc_cond_init( vlc_cond_t *p_condvar )
450 #if defined( LIBVLC_USE_PTHREAD )
451 pthread_condattr_t attr;
454 ret = pthread_condattr_init (&attr);
458 # if !defined (_POSIX_CLOCK_SELECTION)
459 /* Fairly outdated POSIX support (that was defined in 2001) */
460 # define _POSIX_CLOCK_SELECTION (-1)
462 # if (_POSIX_CLOCK_SELECTION >= 0)
463 /* NOTE: This must be the same clock as the one in mtime.c */
464 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
467 ret = pthread_cond_init (p_condvar, &attr);
468 pthread_condattr_destroy (&attr);
471 #elif defined( WIN32 )
472 /* Create a manual-reset event (manual reset is needed for broadcast). */
473 *p_condvar = CreateEvent( NULL, TRUE, FALSE, NULL );
474 return *p_condvar ? 0 : ENOMEM;
480 * Destroys a condition variable. No threads shall be waiting or signaling the
482 * @param p_condvar condition variable to destroy
484 void vlc_cond_destroy (vlc_cond_t *p_condvar)
486 #if defined( LIBVLC_USE_PTHREAD )
487 int val = pthread_cond_destroy( p_condvar );
488 VLC_THREAD_ASSERT ("destroying condition");
490 #elif defined( WIN32 )
491 CloseHandle( *p_condvar );
497 * Wakes up one thread waiting on a condition variable, if any.
498 * @param p_condvar condition variable
500 void vlc_cond_signal (vlc_cond_t *p_condvar)
502 #if defined(LIBVLC_USE_PTHREAD)
503 int val = pthread_cond_signal( p_condvar );
504 VLC_THREAD_ASSERT ("signaling condition variable");
506 #elif defined( WIN32 )
507 /* NOTE: This will cause a broadcast, that is wrong.
508 * This will also wake up the next waiting thread if no thread are yet
509 * waiting, which is also wrong. However both of these issues are allowed
510 * by the provision for spurious wakeups. Better have too many wakeups
511 * than too few (= deadlocks). */
512 SetEvent (*p_condvar);
518 * Wakes up all threads (if any) waiting on a condition variable.
519 * @param p_cond condition variable
521 void vlc_cond_broadcast (vlc_cond_t *p_condvar)
523 #if defined (LIBVLC_USE_PTHREAD)
524 pthread_cond_broadcast (p_condvar);
526 #elif defined (WIN32)
527 SetEvent (*p_condvar);
533 * Waits for a condition variable. The calling thread will be suspended until
534 * another thread calls vlc_cond_signal() or vlc_cond_broadcast() on the same
535 * condition variable, the thread is cancelled with vlc_cancel(), or the
536 * system causes a "spurious" unsolicited wake-up.
538 * A mutex is needed to wait on a condition variable. It must <b>not</b> be
539 * a recursive mutex. Although it is possible to use the same mutex for
540 * multiple condition, it is not valid to use different mutexes for the same
541 * condition variable at the same time from different threads.
543 * In case of thread cancellation, the mutex is always locked before
544 * cancellation proceeds.
546 * The canonical way to use a condition variable to wait for event foobar is:
548 vlc_mutex_lock (&lock);
549 mutex_cleanup_push (&lock); // release the mutex in case of cancellation
552 vlc_cond_wait (&wait, &lock);
554 --- foobar is now true, do something about it here --
556 vlc_cleanup_run (); // release the mutex
559 * @param p_condvar condition variable to wait on
560 * @param p_mutex mutex which is unlocked while waiting,
561 * then locked again when waking up.
562 * @param deadline <b>absolute</b> timeout
564 * @return 0 if the condition was signaled, an error code in case of timeout.
566 void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
568 #if defined(LIBVLC_USE_PTHREAD)
569 int val = pthread_cond_wait( p_condvar, p_mutex );
570 VLC_THREAD_ASSERT ("waiting on condition");
572 #elif defined( WIN32 )
578 LeaveCriticalSection (&p_mutex->mutex);
579 result = WaitForSingleObjectEx (*p_condvar, INFINITE, TRUE);
580 EnterCriticalSection (&p_mutex->mutex);
582 while (result == WAIT_IO_COMPLETION);
584 ResetEvent (*p_condvar);
590 * Waits for a condition variable up to a certain date.
591 * This works like vlc_cond_wait(), except for the additional timeout.
593 * @param p_condvar condition variable to wait on
594 * @param p_mutex mutex which is unlocked while waiting,
595 * then locked again when waking up.
596 * @param deadline <b>absolute</b> timeout
598 * @return 0 if the condition was signaled, an error code in case of timeout.
600 int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
603 #if defined(LIBVLC_USE_PTHREAD)
605 /* mdate() is mac_absolute_time on osx, which we must convert to do
606 * the same base than gettimeofday() on which pthread_cond_timedwait
608 mtime_t oldbase = mdate();
610 gettimeofday(&tv, NULL);
611 mtime_t newbase = (mtime_t)tv.tv_sec * 1000000 + (mtime_t) tv.tv_usec;
612 deadline = deadline - oldbase + newbase;
614 lldiv_t d = lldiv( deadline, CLOCK_FREQ );
615 struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
617 int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
618 if (val != ETIMEDOUT)
619 VLC_THREAD_ASSERT ("timed-waiting on condition");
622 #elif defined( WIN32 )
629 mtime_t total = (deadline - mdate ())/1000;
633 DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
634 LeaveCriticalSection (&p_mutex->mutex);
635 result = WaitForSingleObjectEx (*p_condvar, delay, TRUE);
636 EnterCriticalSection (&p_mutex->mutex);
638 while (result == WAIT_IO_COMPLETION);
640 ResetEvent (*p_condvar);
642 return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
647 /*****************************************************************************
648 * vlc_tls_create: create a thread-local variable
649 *****************************************************************************/
650 int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
654 #if defined( LIBVLC_USE_PTHREAD )
655 i_ret = pthread_key_create( p_tls, destr );
656 #elif defined( WIN32 )
657 /* FIXME: remember/use the destr() callback and stop leaking whatever */
659 i_ret = (*p_tls == TLS_OUT_OF_INDEXES) ? EAGAIN : 0;
661 # error Unimplemented!
666 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
668 #if defined( LIBVLC_USE_PTHREAD )
669 pthread_key_delete (*p_tls);
670 #elif defined( WIN32 )
673 # error Unimplemented!
677 #if defined (LIBVLC_USE_PTHREAD)
678 #elif defined (WIN32)
679 static unsigned __stdcall vlc_entry (void *data)
681 vlc_cancel_t cancel_data = VLC_CANCEL_INIT;
682 vlc_thread_t self = data;
684 cancel_data.cancel_event = self->cancel_event;
687 vlc_threadvar_set (&cancel_key, &cancel_data);
688 self->data = self->entry (self->data);
694 * Creates and starts new thread.
696 * @param p_handle [OUT] pointer to write the handle of the created thread to
697 * @param entry entry point for the thread
698 * @param data data parameter given to the entry point
699 * @param priority thread priority value
700 * @return 0 on success, a standard error code on error.
702 int vlc_clone (vlc_thread_t *p_handle, void * (*entry) (void *), void *data,
707 #if defined( LIBVLC_USE_PTHREAD )
709 pthread_attr_init (&attr);
711 /* Block the signals that signals interface plugin handles.
712 * If the LibVLC caller wants to handle some signals by itself, it should
713 * block these before whenever invoking LibVLC. And it must obviously not
714 * start the VLC signals interface plugin.
716 * LibVLC will normally ignore any interruption caused by an asynchronous
717 * signal during a system call. But there may well be some buggy cases
718 * where it fails to handle EINTR (bug reports welcome). Some underlying
719 * libraries might also not handle EINTR properly.
725 sigdelset (&set, SIGHUP);
726 sigaddset (&set, SIGINT);
727 sigaddset (&set, SIGQUIT);
728 sigaddset (&set, SIGTERM);
730 sigaddset (&set, SIGPIPE); /* We don't want this one, really! */
731 pthread_sigmask (SIG_BLOCK, &set, &oldset);
734 struct sched_param sp = { .sched_priority = priority, };
737 if (sp.sched_priority <= 0)
738 sp.sched_priority += sched_get_priority_max (policy = SCHED_OTHER);
740 sp.sched_priority += sched_get_priority_min (policy = SCHED_RR);
742 pthread_attr_setschedpolicy (&attr, policy);
743 pthread_attr_setschedparam (&attr, &sp);
746 /* The thread stack size.
747 * The lower the value, the less address space per thread, the highest
748 * maximum simultaneous threads per process. Too low values will cause
749 * stack overflows and weird crashes. Set with caution. Also keep in mind
750 * that 64-bits platforms consume more stack than 32-bits one.
752 * Thanks to on-demand paging, thread stack size only affects address space
753 * consumption. In terms of memory, threads only use what they need
754 * (rounded up to the page boundary).
756 * For example, on Linux i386, the default is 2 mega-bytes, which supports
757 * about 320 threads per processes. */
758 #define VLC_STACKSIZE (128 * sizeof (void *) * 1024)
761 ret = pthread_attr_setstacksize (&attr, VLC_STACKSIZE);
762 assert (ret == 0); /* fails iif VLC_STACKSIZE is invalid */
765 ret = pthread_create (p_handle, &attr, entry, data);
766 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
767 pthread_attr_destroy (&attr);
769 #elif defined( WIN32 ) || defined( UNDER_CE )
770 /* When using the MSVCRT C library you have to use the _beginthreadex
771 * function instead of CreateThread, otherwise you'll end up with
772 * memory leaks and the signal functions not working (see Microsoft
773 * Knowledge Base, article 104641) */
775 vlc_thread_t th = malloc (sizeof (*th));
782 #if defined( UNDER_CE )
783 th->cancel_event = CreateEvent (NULL, FALSE, FALSE, NULL);
784 if (th->cancel_event == NULL)
789 hThread = CreateThread (NULL, 128*1024, vlc_entry, th, CREATE_SUSPENDED, NULL);
791 hThread = (HANDLE)(uintptr_t)
792 _beginthreadex (NULL, 0, vlc_entry, th, CREATE_SUSPENDED, NULL);
798 /* Thread closes the handle when exiting, duplicate it here
799 * to be on the safe side when joining. */
800 if (!DuplicateHandle (GetCurrentProcess (), hThread,
801 GetCurrentProcess (), &th->handle, 0, FALSE,
802 DUPLICATE_SAME_ACCESS))
804 CloseHandle (hThread);
809 th->handle = hThread;
812 ResumeThread (hThread);
814 SetThreadPriority (hThread, priority);
830 /* APC procedure for thread cancellation */
831 static void CALLBACK vlc_cancel_self (ULONG_PTR dummy)
834 vlc_control_cancel (VLC_DO_CANCEL);
839 * Marks a thread as cancelled. Next time the target thread reaches a
840 * cancellation point (while not having disabled cancellation), it will
841 * run its cancellation cleanup handler, the thread variable destructors, and
842 * terminate. vlc_join() must be used afterward regardless of a thread being
845 void vlc_cancel (vlc_thread_t thread_id)
847 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
848 pthread_cancel (thread_id);
849 #elif defined (UNDER_CE)
850 SetEvent (thread_id->cancel_event);
851 #elif defined (WIN32)
852 QueueUserAPC (vlc_cancel_self, thread_id->handle, 0);
854 # warning vlc_cancel is not implemented!
859 * Waits for a thread to complete (if needed), and destroys it.
860 * This is a cancellation point; in case of cancellation, the join does _not_
863 * @param handle thread handle
864 * @param p_result [OUT] pointer to write the thread return value or NULL
865 * @return 0 on success, a standard error code otherwise.
867 void vlc_join (vlc_thread_t handle, void **result)
869 #if defined( LIBVLC_USE_PTHREAD )
870 int val = pthread_join (handle, result);
871 VLC_THREAD_ASSERT ("joining thread");
873 #elif defined( UNDER_CE ) || defined( WIN32 )
876 while (WaitForSingleObjectEx (handle->handle, INFINITE, TRUE)
877 == WAIT_IO_COMPLETION);
879 CloseHandle (handle->handle);
881 *result = handle->data;
882 #if defined( UNDER_CE )
883 CloseHandle (handle->cancel_event);
891 * Save the current cancellation state (enabled or disabled), then disable
892 * cancellation for the calling thread.
893 * This function must be called before entering a piece of code that is not
894 * cancellation-safe, unless it can be proven that the calling thread will not
896 * @return Previous cancellation state (opaque value for vlc_restorecancel()).
898 int vlc_savecancel (void)
902 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
903 int val = pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
904 VLC_THREAD_ASSERT ("saving cancellation");
907 vlc_cancel_t *nfo = vlc_threadvar_get (&cancel_key);
909 return false; /* Main thread - cannot be cancelled anyway */
911 state = nfo->killable;
912 nfo->killable = false;
919 * Restore the cancellation state for the calling thread.
920 * @param state previous state as returned by vlc_savecancel().
921 * @return Nothing, always succeeds.
923 void vlc_restorecancel (int state)
925 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
929 val = pthread_setcancelstate (state, &oldstate);
930 /* This should fail if an invalid value for given for state */
931 VLC_THREAD_ASSERT ("restoring cancellation");
933 if (oldstate != PTHREAD_CANCEL_DISABLE)
934 vlc_thread_fatal ("restoring cancellation while not disabled", EINVAL,
935 __func__, __FILE__, __LINE__);
937 pthread_setcancelstate (state, NULL);
941 vlc_cancel_t *nfo = vlc_threadvar_get (&cancel_key);
942 assert (state == false || state == true);
945 return; /* Main thread - cannot be cancelled anyway */
947 assert (!nfo->killable);
948 nfo->killable = state != 0;
954 * Issues an explicit deferred cancellation point.
955 * This has no effect if thread cancellation is disabled.
956 * This can be called when there is a rather slow non-sleeping operation.
957 * This is also used to force a cancellation point in a function that would
958 * otherwise "not always" be a one (block_FifoGet() is an example).
960 void vlc_testcancel (void)
962 #if defined (LIBVLC_USE_PTHREAD_CANCEL)
963 pthread_testcancel ();
966 vlc_cancel_t *nfo = vlc_threadvar_get (&cancel_key);
968 return; /* Main thread - cannot be cancelled anyway */
970 if (nfo->killable && nfo->killed)
972 for (vlc_cleanup_t *p = nfo->cleaners; p != NULL; p = p->next)
974 # if defined (LIBVLC_USE_PTHREAD)
975 pthread_exit (PTHREAD_CANCELLED);
976 # elif defined (UNDER_CE)
978 # elif defined (WIN32)
981 # error Not implemented!
988 struct vlc_thread_boot
990 void * (*entry) (vlc_object_t *);
991 vlc_object_t *object;
994 static void *thread_entry (void *data)
996 vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
997 void *(*func) (vlc_object_t *) = ((struct vlc_thread_boot *)data)->entry;
1000 msg_Dbg (obj, "thread started");
1002 msg_Dbg (obj, "thread ended");
1007 #undef vlc_thread_create
1008 /*****************************************************************************
1009 * vlc_thread_create: create a thread
1010 *****************************************************************************
1011 * Note that i_priority is only taken into account on platforms supporting
1012 * userland real-time priority threads.
1013 *****************************************************************************/
1014 int vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
1015 const char *psz_name, void *(*func) ( vlc_object_t * ),
1019 vlc_object_internals_t *p_priv = vlc_internals( p_this );
1021 struct vlc_thread_boot *boot = malloc (sizeof (*boot));
1025 boot->object = p_this;
1027 /* Make sure we don't re-create a thread if the object has already one */
1028 assert( !p_priv->b_thread );
1030 #if defined( LIBVLC_USE_PTHREAD )
1032 if( config_GetInt( p_this, "rt-priority" ) > 0 )
1035 /* Hack to avoid error msg */
1036 if( config_GetType( p_this, "rt-offset" ) )
1037 i_priority += config_GetInt( p_this, "rt-offset" );
1041 p_priv->b_thread = true;
1042 i_ret = vlc_clone( &p_priv->thread_id, thread_entry, boot, i_priority );
1044 msg_Dbg( p_this, "thread (%s) created at priority %d (%s:%d)",
1045 psz_name, i_priority, psz_file, i_line );
1048 p_priv->b_thread = false;
1050 msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
1051 psz_name, psz_file, i_line );
1057 /*****************************************************************************
1058 * vlc_thread_set_priority: set the priority of the current thread when we
1059 * couldn't set it in vlc_thread_create (for instance for the main thread)
1060 *****************************************************************************/
1061 int __vlc_thread_set_priority( vlc_object_t *p_this, const char * psz_file,
1062 int i_line, int i_priority )
1064 vlc_object_internals_t *p_priv = vlc_internals( p_this );
1066 if( !p_priv->b_thread )
1068 msg_Err( p_this, "couldn't set priority of non-existent thread" );
1072 #if defined( LIBVLC_USE_PTHREAD )
1074 if( config_GetInt( p_this, "rt-priority" ) > 0 )
1077 int i_error, i_policy;
1078 struct sched_param param;
1080 memset( ¶m, 0, sizeof(struct sched_param) );
1081 if( config_GetType( p_this, "rt-offset" ) )
1082 i_priority += config_GetInt( p_this, "rt-offset" );
1083 if( i_priority <= 0 )
1085 param.sched_priority = (-1) * i_priority;
1086 i_policy = SCHED_OTHER;
1090 param.sched_priority = i_priority;
1091 i_policy = SCHED_RR;
1093 if( (i_error = pthread_setschedparam( p_priv->thread_id,
1094 i_policy, ¶m )) )
1097 msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
1103 #elif defined( WIN32 ) || defined( UNDER_CE )
1104 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
1106 if( !SetThreadPriority(p_priv->thread_id->handle, i_priority) )
1108 msg_Warn( p_this, "couldn't set a faster priority" );
1117 /*****************************************************************************
1118 * vlc_thread_join: wait until a thread exits, inner version
1119 *****************************************************************************/
1120 void __vlc_thread_join( vlc_object_t *p_this )
1122 vlc_object_internals_t *p_priv = vlc_internals( p_this );
1124 #if defined( LIBVLC_USE_PTHREAD )
1125 vlc_join (p_priv->thread_id, NULL);
1127 #elif defined( UNDER_CE ) || defined( WIN32 )
1129 FILETIME create_ft, exit_ft, kernel_ft, user_ft;
1130 int64_t real_time, kernel_time, user_time;
1133 if( ! DuplicateHandle(GetCurrentProcess(),
1134 p_priv->thread_id->handle,
1135 GetCurrentProcess(),
1139 DUPLICATE_SAME_ACCESS) )
1141 p_priv->b_thread = false;
1142 return; /* We have a problem! */
1145 hThread = p_priv->thread_id->handle;
1148 vlc_join( p_priv->thread_id, NULL );
1150 if( GetThreadTimes( hThread, &create_ft, &exit_ft, &kernel_ft, &user_ft ) )
1153 ((((int64_t)exit_ft.dwHighDateTime)<<32)| exit_ft.dwLowDateTime) -
1154 ((((int64_t)create_ft.dwHighDateTime)<<32)| create_ft.dwLowDateTime);
1158 ((((int64_t)kernel_ft.dwHighDateTime)<<32)|
1159 kernel_ft.dwLowDateTime) / 10;
1162 ((((int64_t)user_ft.dwHighDateTime)<<32)|
1163 user_ft.dwLowDateTime) / 10;
1165 msg_Dbg( p_this, "thread times: "
1166 "real %"PRId64"m%fs, kernel %"PRId64"m%fs, user %"PRId64"m%fs",
1167 real_time/60/1000000,
1168 (double)((real_time%(60*1000000))/1000000.0),
1169 kernel_time/60/1000000,
1170 (double)((kernel_time%(60*1000000))/1000000.0),
1171 user_time/60/1000000,
1172 (double)((user_time%(60*1000000))/1000000.0) );
1174 CloseHandle( hThread );
1177 vlc_join( p_priv->thread_id, NULL );
1181 p_priv->b_thread = false;
1184 void vlc_thread_cancel (vlc_object_t *obj)
1186 vlc_object_internals_t *priv = vlc_internals (obj);
1189 vlc_cancel (priv->thread_id);
1192 void vlc_control_cancel (int cmd, ...)
1194 /* NOTE: This function only modifies thread-specific data, so there is no
1195 * need to lock anything. */
1196 #ifdef LIBVLC_USE_PTHREAD_CANCEL
1202 vlc_cancel_t *nfo = vlc_threadvar_get (&cancel_key);
1206 /* Main thread - cannot be cancelled anyway */
1209 nfo = malloc (sizeof (*nfo));
1211 return; /* Uho! Expect problems! */
1212 *nfo = VLC_CANCEL_INIT;
1213 vlc_threadvar_set (&cancel_key, nfo);
1224 case VLC_CLEANUP_PUSH:
1226 /* cleaner is a pointer to the caller stack, no need to allocate
1227 * and copy anything. As a nice side effect, this cannot fail. */
1228 vlc_cleanup_t *cleaner = va_arg (ap, vlc_cleanup_t *);
1229 cleaner->next = nfo->cleaners;
1230 nfo->cleaners = cleaner;
1234 case VLC_CLEANUP_POP:
1236 nfo->cleaners = nfo->cleaners->next;