1 /*****************************************************************************
2 * threads.c : threads implementation for the VideoLAN client
3 *****************************************************************************
4 * Copyright (C) 1999-2007 the VideoLAN team
7 * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
8 * Samuel Hocevar <sam@zoy.org>
9 * Gildas Bazin <gbazin@netcourrier.com>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
31 #include <vlc_common.h>
40 #define VLC_THREADS_UNINITIALIZED 0
41 #define VLC_THREADS_PENDING 1
42 #define VLC_THREADS_ERROR 2
43 #define VLC_THREADS_READY 3
45 /*****************************************************************************
46 * Global mutex for lazy initialization of the threads system
47 *****************************************************************************/
48 static volatile unsigned i_initializations = 0;
50 #if defined( LIBVLC_USE_PTHREAD )
53 static pthread_mutex_t once_mutex = PTHREAD_MUTEX_INITIALIZER;
57 * Global process-wide VLC object.
58 * Contains inter-instance data, such as the module cache and global mutexes.
60 static libvlc_global_data_t *p_root;
62 libvlc_global_data_t *vlc_global( void )
64 assert( i_initializations > 0 );
70 * Object running the current thread
72 static vlc_threadvar_t thread_object_key;
74 vlc_object_t *vlc_threadobj (void)
76 return vlc_threadvar_get (&thread_object_key);
80 vlc_threadvar_t msg_context_global_key;
82 #if defined(LIBVLC_USE_PTHREAD)
83 static inline unsigned long vlc_threadid (void)
85 union { pthread_t th; unsigned long int i; } v = { };
86 v.th = pthread_self ();
90 #if defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE)
91 # include <execinfo.h>
94 /*****************************************************************************
95 * vlc_thread_fatal: Report an error from the threading layer
96 *****************************************************************************
97 * This is mostly meant for debugging.
98 *****************************************************************************/
99 void vlc_pthread_fatal (const char *action, int error,
100 const char *file, unsigned line)
102 fprintf (stderr, "LibVLC fatal error %s in thread %lu at %s:%u: %d\n",
103 action, vlc_threadid (), file, line, error);
105 /* Sometimes strerror_r() crashes too, so make sure we print an error
106 * message before we invoke it */
108 /* Avoid the strerror_r() prototype brain damage in glibc */
110 fprintf (stderr, " Error message: %m at:\n");
115 switch (strerror_r (error, buf, sizeof (buf)))
120 case ERANGE: /* should never happen */
121 msg = "unknwon (too big to display)";
124 msg = "unknown (invalid error number)";
127 fprintf (stderr, " Error message: %s\n", msg);
131 #ifdef HAVE_BACKTRACE
133 int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
134 backtrace_symbols_fd (stack, len, 2);
140 void vlc_pthread_fatal (const char *action, int error,
141 const char *file, unsigned line)
143 (void)action; (void)error; (void)file; (void)line;
148 /*****************************************************************************
149 * vlc_threads_init: initialize threads system
150 *****************************************************************************
151 * This function requires lazy initialization of a global lock in order to
152 * keep the library really thread-safe. Some architectures don't support this
153 * and thus do not guarantee the complete reentrancy.
154 *****************************************************************************/
155 int vlc_threads_init( void )
157 int i_ret = VLC_SUCCESS;
159 /* If we have lazy mutex initialization, use it. Otherwise, we just
160 * hope nothing wrong happens. */
161 #if defined( LIBVLC_USE_PTHREAD )
162 pthread_mutex_lock( &once_mutex );
165 if( i_initializations == 0 )
167 p_root = vlc_custom_create( (vlc_object_t *)NULL, sizeof( *p_root ),
168 VLC_OBJECT_GENERIC, "root" );
175 /* We should be safe now. Do all the initialization stuff we want. */
177 vlc_threadvar_create( &thread_object_key, NULL );
179 vlc_threadvar_create( &msg_context_global_key, msg_StackDestroy );
184 /* If we have lazy mutex initialization support, unlock the mutex.
185 * Otherwize, we are screwed. */
186 #if defined( LIBVLC_USE_PTHREAD )
187 pthread_mutex_unlock( &once_mutex );
193 /*****************************************************************************
194 * vlc_threads_end: stop threads system
195 *****************************************************************************
196 * FIXME: This function is far from being threadsafe.
197 *****************************************************************************/
198 void vlc_threads_end( void )
200 #if defined( LIBVLC_USE_PTHREAD )
201 pthread_mutex_lock( &once_mutex );
204 assert( i_initializations > 0 );
206 if( i_initializations == 1 )
208 vlc_object_release( p_root );
209 vlc_threadvar_delete( &msg_context_global_key );
211 vlc_threadvar_delete( &thread_object_key );
216 #if defined( LIBVLC_USE_PTHREAD )
217 pthread_mutex_unlock( &once_mutex );
221 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
222 /* This is not prototyped under glibc, though it exists. */
223 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
226 /*****************************************************************************
227 * vlc_mutex_init: initialize a mutex
228 *****************************************************************************/
229 int vlc_mutex_init( vlc_mutex_t *p_mutex )
231 #if defined( LIBVLC_USE_PTHREAD )
232 pthread_mutexattr_t attr;
235 pthread_mutexattr_init( &attr );
238 /* Create error-checking mutex to detect problems more easily. */
239 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
240 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
242 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
245 i_result = pthread_mutex_init( p_mutex, &attr );
246 pthread_mutexattr_destroy( &attr );
248 #elif defined( UNDER_CE )
249 InitializeCriticalSection( &p_mutex->csection );
252 #elif defined( WIN32 )
253 *p_mutex = CreateMutex( 0, FALSE, 0 );
254 return (*p_mutex != NULL) ? 0 : ENOMEM;
256 #elif defined( HAVE_KERNEL_SCHEDULER_H )
257 /* check the arguments and whether it's already been initialized */
258 if( p_mutex == NULL )
263 if( p_mutex->init == 9999 )
268 p_mutex->lock = create_sem( 1, "BeMutex" );
269 if( p_mutex->lock < B_NO_ERROR )
274 p_mutex->init = 9999;
280 /*****************************************************************************
281 * vlc_mutex_init: initialize a recursive mutex (Do not use)
282 *****************************************************************************/
283 int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
285 #if defined( LIBVLC_USE_PTHREAD )
286 pthread_mutexattr_t attr;
289 pthread_mutexattr_init( &attr );
290 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
291 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
293 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
295 i_result = pthread_mutex_init( p_mutex, &attr );
296 pthread_mutexattr_destroy( &attr );
298 #elif defined( WIN32 )
299 /* Create mutex returns a recursive mutex */
300 *p_mutex = CreateMutex( 0, FALSE, 0 );
301 return (*p_mutex != NULL) ? 0 : ENOMEM;
303 # error Unimplemented!
308 /*****************************************************************************
309 * vlc_mutex_destroy: destroy a mutex, inner version
310 *****************************************************************************/
311 void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
313 #if defined( LIBVLC_USE_PTHREAD )
314 int val = pthread_mutex_destroy( p_mutex );
315 VLC_THREAD_ASSERT ("destroying mutex");
317 #elif defined( UNDER_CE )
318 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
320 DeleteCriticalSection( &p_mutex->csection );
322 #elif defined( WIN32 )
323 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
325 CloseHandle( *p_mutex );
327 #elif defined( HAVE_KERNEL_SCHEDULER_H )
328 if( p_mutex->init == 9999 )
329 delete_sem( p_mutex->lock );
336 /*****************************************************************************
337 * vlc_cond_init: initialize a condition
338 *****************************************************************************/
339 int __vlc_cond_init( vlc_cond_t *p_condvar )
341 #if defined( LIBVLC_USE_PTHREAD )
342 pthread_condattr_t attr;
345 ret = pthread_condattr_init (&attr);
349 # if !defined (_POSIX_CLOCK_SELECTION)
350 /* Fairly outdated POSIX support (that was defined in 2001) */
351 # define _POSIX_CLOCK_SELECTION (-1)
353 # if (_POSIX_CLOCK_SELECTION >= 0)
354 /* NOTE: This must be the same clock as the one in mtime.c */
355 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
358 ret = pthread_cond_init (p_condvar, &attr);
359 pthread_condattr_destroy (&attr);
362 #elif defined( UNDER_CE ) || defined( WIN32 )
363 /* Initialize counter */
364 p_condvar->i_waiting_threads = 0;
366 /* Create an auto-reset event. */
367 p_condvar->event = CreateEvent( NULL, /* no security */
368 FALSE, /* auto-reset event */
369 FALSE, /* start non-signaled */
370 NULL ); /* unnamed */
371 return !p_condvar->event;
373 #elif defined( HAVE_KERNEL_SCHEDULER_H )
379 if( p_condvar->init == 9999 )
384 p_condvar->thread = -1;
385 p_condvar->init = 9999;
391 /*****************************************************************************
392 * vlc_cond_destroy: destroy a condition, inner version
393 *****************************************************************************/
394 void __vlc_cond_destroy( const char * psz_file, int i_line, vlc_cond_t *p_condvar )
396 #if defined( LIBVLC_USE_PTHREAD )
397 int val = pthread_cond_destroy( p_condvar );
398 VLC_THREAD_ASSERT ("destroying condition");
400 #elif defined( UNDER_CE ) || defined( WIN32 )
401 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
403 CloseHandle( p_condvar->event );
405 #elif defined( HAVE_KERNEL_SCHEDULER_H )
411 /*****************************************************************************
412 * vlc_tls_create: create a thread-local variable
413 *****************************************************************************/
414 int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
418 #if defined( LIBVLC_USE_PTHREAD )
419 i_ret = pthread_key_create( p_tls, destr );
420 #elif defined( UNDER_CE )
422 #elif defined( WIN32 )
424 i_ret = (*p_tls == TLS_OUT_OF_INDEXES) ? EAGAIN : 0;
426 # error Unimplemented!
431 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
433 #if defined( LIBVLC_USE_PTHREAD )
434 pthread_key_delete (*p_tls);
435 #elif defined( UNDER_CE )
436 #elif defined( WIN32 )
439 # error Unimplemented!
443 struct vlc_thread_boot
445 void * (*entry) (void *);
446 vlc_object_t *object;
449 #if defined (LIBVLC_USE_PTHREAD)
450 # define THREAD_RTYPE void *
451 # define THREAD_RVAL NULL
452 #elif defined (WIN32)
453 # define THREAD_RTYPE __stdcall unsigned
454 # define THREAD_RVAL 0
457 static THREAD_RTYPE thread_entry (void *data)
459 vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
460 void *(*func) (void *) = ((struct vlc_thread_boot *)data)->entry;
464 vlc_threadvar_set (&thread_object_key, obj);
466 msg_Dbg (obj, "thread started");
468 msg_Dbg (obj, "thread ended");
470 libvlc_priv_t *libpriv = libvlc_priv (obj->p_libvlc);
471 vlc_mutex_lock (&libpriv->threads_lock);
472 if (--libpriv->threads_count == 0)
473 vlc_cond_signal (&libpriv->threads_wait);
474 vlc_mutex_unlock (&libpriv->threads_lock);
478 /*****************************************************************************
479 * vlc_thread_create: create a thread, inner version
480 *****************************************************************************
481 * Note that i_priority is only taken into account on platforms supporting
482 * userland real-time priority threads.
483 *****************************************************************************/
484 int __vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
485 const char *psz_name, void * ( *func ) ( void * ),
486 int i_priority, bool b_wait )
489 vlc_object_internals_t *p_priv = vlc_internals( p_this );
490 libvlc_priv_t *libpriv = libvlc_priv (p_this->p_libvlc);
492 struct vlc_thread_boot *boot = malloc (sizeof (*boot));
496 boot->object = p_this;
498 vlc_mutex_lock (&libpriv->threads_lock);
499 libpriv->threads_count++;
500 vlc_mutex_unlock (&libpriv->threads_lock);
502 vlc_object_lock( p_this );
504 #if defined( LIBVLC_USE_PTHREAD )
506 pthread_attr_init (&attr);
508 /* Block the signals that signals interface plugin handles.
509 * If the LibVLC caller wants to handle some signals by itself, it should
510 * block these before whenever invoking LibVLC. And it must obviously not
511 * start the VLC signals interface plugin.
513 * LibVLC will normally ignore any interruption caused by an asynchronous
514 * signal during a system call. But there may well be some buggy cases
515 * where it fails to handle EINTR (bug reports welcome). Some underlying
516 * libraries might also not handle EINTR properly.
518 sigset_t set, oldset;
520 sigdelset (&set, SIGHUP);
521 sigaddset (&set, SIGINT);
522 sigaddset (&set, SIGQUIT);
523 sigaddset (&set, SIGTERM);
525 sigaddset (&set, SIGPIPE); /* We don't want this one, really! */
526 pthread_sigmask (SIG_BLOCK, &set, &oldset);
529 if( config_GetInt( p_this, "rt-priority" ) > 0 )
532 struct sched_param p = { .sched_priority = i_priority, };
535 /* Hack to avoid error msg */
536 if( config_GetType( p_this, "rt-offset" ) )
537 p.sched_priority += config_GetInt( p_this, "rt-offset" );
538 if( p.sched_priority <= 0 )
539 p.sched_priority += sched_get_priority_max (policy = SCHED_OTHER);
541 p.sched_priority += sched_get_priority_min (policy = SCHED_RR);
543 pthread_attr_setschedpolicy (&attr, policy);
544 pthread_attr_setschedparam (&attr, &p);
547 i_ret = pthread_create( &p_priv->thread_id, &attr, thread_entry, boot );
548 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
549 pthread_attr_destroy (&attr);
551 #elif defined( WIN32 ) || defined( UNDER_CE )
552 /* When using the MSVCRT C library you have to use the _beginthreadex
553 * function instead of CreateThread, otherwise you'll end up with
554 * memory leaks and the signal functions not working (see Microsoft
555 * Knowledge Base, article 104641) */
556 #if defined( UNDER_CE )
557 HANDLE hThread = CreateThread( NULL, 0, thread_entry,
558 (LPVOID)boot, CREATE_SUSPENDED, NULL );
560 HANDLE hThread = (HANDLE)(uintptr_t)
561 _beginthreadex( NULL, 0, thread_entry, boot, CREATE_SUSPENDED, NULL );
565 p_priv->thread_id = hThread;
566 ResumeThread (hThread);
568 if( i_priority && !SetThreadPriority (hThread, i_priority) )
570 msg_Warn( p_this, "couldn't set a faster priority" );
577 #elif defined( HAVE_KERNEL_SCHEDULER_H )
578 p_priv->thread_id = spawn_thread( (thread_func)thread_entry, psz_name,
579 i_priority, p_data );
580 i_ret = resume_thread( p_priv->thread_id );
588 msg_Dbg( p_this, "waiting for thread completion" );
589 vlc_object_wait( p_this );
592 p_priv->b_thread = true;
593 msg_Dbg( p_this, "thread %lu (%s) created at priority %d (%s:%d)",
594 (unsigned long)p_priv->thread_id, psz_name, i_priority,
600 msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
601 psz_name, psz_file, i_line );
604 vlc_object_unlock( p_this );
608 vlc_mutex_lock (&libpriv->threads_lock);
609 if (--libpriv->threads_count == 0)
610 vlc_cond_signal (&libpriv->threads_wait);
611 vlc_mutex_unlock (&libpriv->threads_lock);
616 /*****************************************************************************
617 * vlc_thread_set_priority: set the priority of the current thread when we
618 * couldn't set it in vlc_thread_create (for instance for the main thread)
619 *****************************************************************************/
620 int __vlc_thread_set_priority( vlc_object_t *p_this, const char * psz_file,
621 int i_line, int i_priority )
623 vlc_object_internals_t *p_priv = vlc_internals( p_this );
625 if( !p_priv->b_thread )
628 msg_Err( p_this, "couldn't set priority of non-existent thread" );
631 # warning FIXME: this is wrong
632 p_priv->b_thread = pthread_self();
636 #if defined( LIBVLC_USE_PTHREAD )
638 if( config_GetInt( p_this, "rt-priority" ) > 0 )
641 int i_error, i_policy;
642 struct sched_param param;
644 memset( ¶m, 0, sizeof(struct sched_param) );
645 if( config_GetType( p_this, "rt-offset" ) )
646 i_priority += config_GetInt( p_this, "rt-offset" );
647 if( i_priority <= 0 )
649 param.sched_priority = (-1) * i_priority;
650 i_policy = SCHED_OTHER;
654 param.sched_priority = i_priority;
657 if( (i_error = pthread_setschedparam( p_priv->thread_id,
658 i_policy, ¶m )) )
661 msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
667 #elif defined( WIN32 ) || defined( UNDER_CE )
668 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
670 if( !SetThreadPriority(p_priv->thread_id, i_priority) )
672 msg_Warn( p_this, "couldn't set a faster priority" );
681 /*****************************************************************************
682 * vlc_thread_join: wait until a thread exits, inner version
683 *****************************************************************************/
684 void __vlc_thread_join( vlc_object_t *p_this, const char * psz_file, int i_line )
686 vlc_object_internals_t *p_priv = vlc_internals( p_this );
689 #if defined( LIBVLC_USE_PTHREAD )
690 /* Make sure we do return if we are calling vlc_thread_join()
691 * from the joined thread */
692 if (pthread_equal (pthread_self (), p_priv->thread_id))
694 msg_Warn (p_this, "joining the active thread (VLC might crash)");
695 i_ret = pthread_detach (p_priv->thread_id);
698 i_ret = pthread_join (p_priv->thread_id, NULL);
700 #elif defined( UNDER_CE ) || defined( WIN32 )
702 BOOL (WINAPI *OurGetThreadTimes)( HANDLE, FILETIME*, FILETIME*,
703 FILETIME*, FILETIME* );
704 FILETIME create_ft, exit_ft, kernel_ft, user_ft;
705 int64_t real_time, kernel_time, user_time;
709 ** object will close its thread handle when destroyed, duplicate it here
710 ** to be on the safe side
712 if( ! DuplicateHandle(GetCurrentProcess(),
718 DUPLICATE_SAME_ACCESS) )
720 p_priv->b_thread = false;
721 i_ret = GetLastError();
725 WaitForSingleObject( hThread, INFINITE );
727 #if defined( UNDER_CE )
728 hmodule = GetModuleHandle( _T("COREDLL") );
730 hmodule = GetModuleHandle( _T("KERNEL32") );
732 OurGetThreadTimes = (BOOL (WINAPI*)( HANDLE, FILETIME*, FILETIME*,
733 FILETIME*, FILETIME* ))
734 GetProcAddress( hmodule, _T("GetThreadTimes") );
736 if( OurGetThreadTimes &&
737 OurGetThreadTimes( hThread,
738 &create_ft, &exit_ft, &kernel_ft, &user_ft ) )
741 ((((int64_t)exit_ft.dwHighDateTime)<<32)| exit_ft.dwLowDateTime) -
742 ((((int64_t)create_ft.dwHighDateTime)<<32)| create_ft.dwLowDateTime);
746 ((((int64_t)kernel_ft.dwHighDateTime)<<32)|
747 kernel_ft.dwLowDateTime) / 10;
750 ((((int64_t)user_ft.dwHighDateTime)<<32)|
751 user_ft.dwLowDateTime) / 10;
753 msg_Dbg( p_this, "thread times: "
754 "real %"PRId64"m%fs, kernel %"PRId64"m%fs, user %"PRId64"m%fs",
755 real_time/60/1000000,
756 (double)((real_time%(60*1000000))/1000000.0),
757 kernel_time/60/1000000,
758 (double)((kernel_time%(60*1000000))/1000000.0),
759 user_time/60/1000000,
760 (double)((user_time%(60*1000000))/1000000.0) );
762 CloseHandle( hThread );
765 #elif defined( HAVE_KERNEL_SCHEDULER_H )
767 i_ret = (B_OK == wait_for_thread( p_priv->thread_id, &exit_value ));
774 msg_Err( p_this, "thread_join(%lu) failed at %s:%d (%m)",
775 (unsigned long)p_priv->thread_id, psz_file, i_line );
778 msg_Dbg( p_this, "thread %lu joined (%s:%d)",
779 (unsigned long)p_priv->thread_id, psz_file, i_line );
781 p_priv->b_thread = false;