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);
106 /* Sometimes strerror_r() crashes too, so make sure we print an error
107 * message before we invoke it */
109 /* Avoid the strerror_r() prototype brain damage in glibc */
111 dprintf (2, " Error message: %m at:\n");
116 switch (strerror_r (error, buf, sizeof (buf)))
121 case ERANGE: /* should never happen */
122 msg = "unknwon (too big to display)";
125 msg = "unknown (invalid error number)";
128 fprintf (stderr, " Error message: %s\n", msg);
132 #ifdef HAVE_BACKTRACE
134 int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
135 backtrace_symbols_fd (stack, len, 2);
141 void vlc_pthread_fatal (const char *action, int error,
142 const char *file, unsigned line)
144 (void)action; (void)error; (void)file; (void)line;
149 /*****************************************************************************
150 * vlc_threads_init: initialize threads system
151 *****************************************************************************
152 * This function requires lazy initialization of a global lock in order to
153 * keep the library really thread-safe. Some architectures don't support this
154 * and thus do not guarantee the complete reentrancy.
155 *****************************************************************************/
156 int vlc_threads_init( void )
158 int i_ret = VLC_SUCCESS;
160 /* If we have lazy mutex initialization, use it. Otherwise, we just
161 * hope nothing wrong happens. */
162 #if defined( LIBVLC_USE_PTHREAD )
163 pthread_mutex_lock( &once_mutex );
166 if( i_initializations == 0 )
168 p_root = vlc_custom_create( NULL, sizeof( *p_root ),
169 VLC_OBJECT_GENERIC, "root" );
176 /* We should be safe now. Do all the initialization stuff we want. */
178 vlc_threadvar_create( &thread_object_key, NULL );
180 vlc_threadvar_create( &msg_context_global_key, msg_StackDestroy );
185 /* If we have lazy mutex initialization support, unlock the mutex.
186 * Otherwize, we are screwed. */
187 #if defined( LIBVLC_USE_PTHREAD )
188 pthread_mutex_unlock( &once_mutex );
194 /*****************************************************************************
195 * vlc_threads_end: stop threads system
196 *****************************************************************************
197 * FIXME: This function is far from being threadsafe.
198 *****************************************************************************/
199 void vlc_threads_end( void )
201 #if defined( LIBVLC_USE_PTHREAD )
202 pthread_mutex_lock( &once_mutex );
205 assert( i_initializations > 0 );
207 if( i_initializations == 1 )
209 vlc_object_release( p_root );
210 vlc_threadvar_delete( &msg_context_global_key );
212 vlc_threadvar_delete( &thread_object_key );
217 #if defined( LIBVLC_USE_PTHREAD )
218 pthread_mutex_unlock( &once_mutex );
222 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
223 /* This is not prototyped under glibc, though it exists. */
224 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
227 /*****************************************************************************
228 * vlc_mutex_init: initialize a mutex
229 *****************************************************************************/
230 int vlc_mutex_init( vlc_mutex_t *p_mutex )
232 #if defined( LIBVLC_USE_PTHREAD )
233 pthread_mutexattr_t attr;
236 pthread_mutexattr_init( &attr );
239 /* Create error-checking mutex to detect problems more easily. */
240 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
241 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
243 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
246 i_result = pthread_mutex_init( p_mutex, &attr );
247 pthread_mutexattr_destroy( &attr );
249 #elif defined( UNDER_CE )
250 InitializeCriticalSection( &p_mutex->csection );
253 #elif defined( WIN32 )
254 *p_mutex = CreateMutex( 0, FALSE, 0 );
255 return (*p_mutex != NULL) ? 0 : ENOMEM;
257 #elif defined( HAVE_KERNEL_SCHEDULER_H )
258 /* check the arguments and whether it's already been initialized */
259 if( p_mutex == NULL )
264 if( p_mutex->init == 9999 )
269 p_mutex->lock = create_sem( 1, "BeMutex" );
270 if( p_mutex->lock < B_NO_ERROR )
275 p_mutex->init = 9999;
281 /*****************************************************************************
282 * vlc_mutex_init: initialize a recursive mutex (Do not use)
283 *****************************************************************************/
284 int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
286 #if defined( LIBVLC_USE_PTHREAD )
287 pthread_mutexattr_t attr;
290 pthread_mutexattr_init( &attr );
291 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
292 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
294 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
296 i_result = pthread_mutex_init( p_mutex, &attr );
297 pthread_mutexattr_destroy( &attr );
299 #elif defined( WIN32 )
300 /* Create mutex returns a recursive mutex */
301 *p_mutex = CreateMutex( 0, FALSE, 0 );
302 return (*p_mutex != NULL) ? 0 : ENOMEM;
304 # error Unimplemented!
309 /*****************************************************************************
310 * vlc_mutex_destroy: destroy a mutex, inner version
311 *****************************************************************************/
312 void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
314 #if defined( LIBVLC_USE_PTHREAD )
315 int val = pthread_mutex_destroy( p_mutex );
316 VLC_THREAD_ASSERT ("destroying mutex");
318 #elif defined( UNDER_CE )
319 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
321 DeleteCriticalSection( &p_mutex->csection );
323 #elif defined( WIN32 )
324 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
326 CloseHandle( *p_mutex );
328 #elif defined( HAVE_KERNEL_SCHEDULER_H )
329 if( p_mutex->init == 9999 )
330 delete_sem( p_mutex->lock );
337 /*****************************************************************************
338 * vlc_cond_init: initialize a condition
339 *****************************************************************************/
340 int __vlc_cond_init( vlc_cond_t *p_condvar )
342 #if defined( LIBVLC_USE_PTHREAD )
343 pthread_condattr_t attr;
346 ret = pthread_condattr_init (&attr);
350 # if !defined (_POSIX_CLOCK_SELECTION)
351 /* Fairly outdated POSIX support (that was defined in 2001) */
352 # define _POSIX_CLOCK_SELECTION (-1)
354 # if (_POSIX_CLOCK_SELECTION >= 0)
355 /* NOTE: This must be the same clock as the one in mtime.c */
356 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
359 ret = pthread_cond_init (p_condvar, &attr);
360 pthread_condattr_destroy (&attr);
363 #elif defined( UNDER_CE ) || defined( WIN32 )
364 /* Initialize counter */
365 p_condvar->i_waiting_threads = 0;
367 /* Create an auto-reset event. */
368 p_condvar->event = CreateEvent( NULL, /* no security */
369 FALSE, /* auto-reset event */
370 FALSE, /* start non-signaled */
371 NULL ); /* unnamed */
372 return !p_condvar->event;
374 #elif defined( HAVE_KERNEL_SCHEDULER_H )
380 if( p_condvar->init == 9999 )
385 p_condvar->thread = -1;
386 p_condvar->init = 9999;
392 /*****************************************************************************
393 * vlc_cond_destroy: destroy a condition, inner version
394 *****************************************************************************/
395 void __vlc_cond_destroy( const char * psz_file, int i_line, vlc_cond_t *p_condvar )
397 #if defined( LIBVLC_USE_PTHREAD )
398 int val = pthread_cond_destroy( p_condvar );
399 VLC_THREAD_ASSERT ("destroying condition");
401 #elif defined( UNDER_CE ) || defined( WIN32 )
402 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
404 CloseHandle( p_condvar->event );
406 #elif defined( HAVE_KERNEL_SCHEDULER_H )
412 /*****************************************************************************
413 * vlc_tls_create: create a thread-local variable
414 *****************************************************************************/
415 int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
419 #if defined( LIBVLC_USE_PTHREAD )
420 i_ret = pthread_key_create( p_tls, destr );
421 #elif defined( UNDER_CE )
423 #elif defined( WIN32 )
425 i_ret = (*p_tls == TLS_OUT_OF_INDEXES) ? EAGAIN : 0;
427 # error Unimplemented!
432 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
434 #if defined( LIBVLC_USE_PTHREAD )
435 pthread_key_delete (*p_tls);
436 #elif defined( UNDER_CE )
437 #elif defined( WIN32 )
440 # error Unimplemented!
444 struct vlc_thread_boot
446 void * (*entry) (void *);
447 vlc_object_t *object;
450 #if defined (LIBVLC_USE_PTHREAD)
451 # define THREAD_RTYPE void *
452 # define THREAD_RVAL NULL
453 #elif defined (WIN32)
454 # define THREAD_RTYPE __stdcall unsigned
455 # define THREAD_RVAL 0
458 static THREAD_RTYPE thread_entry (void *data)
460 vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
461 void *(*func) (void *) = ((struct vlc_thread_boot *)data)->entry;
465 vlc_threadvar_set (&thread_object_key, obj);
467 msg_Dbg (obj, "thread started");
469 msg_Dbg (obj, "thread ended");
471 libvlc_priv_t *libpriv = libvlc_priv (obj->p_libvlc);
472 vlc_mutex_lock (&libpriv->threads_lock);
473 if (--libpriv->threads_count == 0)
474 vlc_cond_signal (&libpriv->threads_wait);
475 vlc_mutex_unlock (&libpriv->threads_lock);
479 /*****************************************************************************
480 * vlc_thread_create: create a thread, inner version
481 *****************************************************************************
482 * Note that i_priority is only taken into account on platforms supporting
483 * userland real-time priority threads.
484 *****************************************************************************/
485 int __vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
486 const char *psz_name, void * ( *func ) ( void * ),
487 int i_priority, bool b_wait )
490 vlc_object_internals_t *p_priv = vlc_internals( p_this );
491 libvlc_priv_t *libpriv = libvlc_priv (p_this->p_libvlc);
493 struct vlc_thread_boot *boot = malloc (sizeof (*boot));
497 boot->object = p_this;
499 vlc_mutex_lock (&libpriv->threads_lock);
500 libpriv->threads_count++;
501 vlc_mutex_unlock (&libpriv->threads_lock);
503 vlc_object_lock( p_this );
505 #if defined( LIBVLC_USE_PTHREAD )
507 pthread_attr_init (&attr);
509 /* Block the signals that signals interface plugin handles.
510 * If the LibVLC caller wants to handle some signals by itself, it should
511 * block these before whenever invoking LibVLC. And it must obviously not
512 * start the VLC signals interface plugin.
514 * LibVLC will normally ignore any interruption caused by an asynchronous
515 * signal during a system call. But there may well be some buggy cases
516 * where it fails to handle EINTR (bug reports welcome). Some underlying
517 * libraries might also not handle EINTR properly.
519 sigset_t set, oldset;
521 sigdelset (&set, SIGHUP);
522 sigaddset (&set, SIGINT);
523 sigaddset (&set, SIGQUIT);
524 sigaddset (&set, SIGTERM);
526 sigaddset (&set, SIGPIPE); /* We don't want this one, really! */
527 pthread_sigmask (SIG_BLOCK, &set, &oldset);
530 if( config_GetInt( p_this, "rt-priority" ) > 0 )
533 struct sched_param p = { .sched_priority = i_priority, };
536 /* Hack to avoid error msg */
537 if( config_GetType( p_this, "rt-offset" ) )
538 p.sched_priority += config_GetInt( p_this, "rt-offset" );
539 if( p.sched_priority <= 0 )
540 p.sched_priority += sched_get_priority_max (policy = SCHED_OTHER);
542 p.sched_priority += sched_get_priority_min (policy = SCHED_RR);
544 pthread_attr_setschedpolicy (&attr, policy);
545 pthread_attr_setschedparam (&attr, &p);
548 i_ret = pthread_create( &p_priv->thread_id, &attr, thread_entry, boot );
549 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
550 pthread_attr_destroy (&attr);
552 #elif defined( WIN32 ) || defined( UNDER_CE )
554 /* When using the MSVCRT C library you have to use the _beginthreadex
555 * function instead of CreateThread, otherwise you'll end up with
556 * memory leaks and the signal functions not working (see Microsoft
557 * Knowledge Base, article 104641) */
558 #if defined( UNDER_CE )
559 HANDLE hThread = CreateThread( NULL, 0, thread_entry,
560 (LPVOID)boot, CREATE_SUSPENDED,
563 HANDLE hThread = (HANDLE)(uintptr_t)
564 _beginthreadex( NULL, 0, thread_entry, boot,
565 CREATE_SUSPENDED, NULL );
567 p_priv->thread_id = hThread;
568 ResumeThread(hThread);
571 i_ret = ( p_priv->thread_id ? 0 : errno );
573 if( !i_ret && i_priority )
575 if( !SetThreadPriority(p_priv->thread_id, i_priority) )
577 msg_Warn( p_this, "couldn't set a faster priority" );
582 #elif defined( HAVE_KERNEL_SCHEDULER_H )
583 p_priv->thread_id = spawn_thread( (thread_func)thread_entry, psz_name,
584 i_priority, p_data );
585 i_ret = resume_thread( p_priv->thread_id );
593 msg_Dbg( p_this, "waiting for thread completion" );
594 vlc_object_wait( p_this );
597 p_priv->b_thread = true;
598 msg_Dbg( p_this, "thread %lu (%s) created at priority %d (%s:%d)",
599 (unsigned long)p_priv->thread_id, psz_name, i_priority,
605 msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
606 psz_name, psz_file, i_line );
609 vlc_object_unlock( p_this );
613 vlc_mutex_lock (&libpriv->threads_lock);
614 if (--libpriv->threads_count == 0)
615 vlc_cond_signal (&libpriv->threads_wait);
616 vlc_mutex_unlock (&libpriv->threads_lock);
621 /*****************************************************************************
622 * vlc_thread_set_priority: set the priority of the current thread when we
623 * couldn't set it in vlc_thread_create (for instance for the main thread)
624 *****************************************************************************/
625 int __vlc_thread_set_priority( vlc_object_t *p_this, const char * psz_file,
626 int i_line, int i_priority )
628 vlc_object_internals_t *p_priv = vlc_internals( p_this );
630 #if defined( LIBVLC_USE_PTHREAD )
632 if( config_GetInt( p_this, "rt-priority" ) > 0 )
635 int i_error, i_policy;
636 struct sched_param param;
638 memset( ¶m, 0, sizeof(struct sched_param) );
639 if( config_GetType( p_this, "rt-offset" ) )
640 i_priority += config_GetInt( p_this, "rt-offset" );
641 if( i_priority <= 0 )
643 param.sched_priority = (-1) * i_priority;
644 i_policy = SCHED_OTHER;
648 param.sched_priority = i_priority;
651 if( !p_priv->thread_id )
652 p_priv->thread_id = pthread_self();
653 if( (i_error = pthread_setschedparam( p_priv->thread_id,
654 i_policy, ¶m )) )
657 msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
663 #elif defined( WIN32 ) || defined( UNDER_CE )
664 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
666 if( !p_priv->thread_id )
667 p_priv->thread_id = GetCurrentThread();
668 if( !SetThreadPriority(p_priv->thread_id, i_priority) )
670 msg_Warn( p_this, "couldn't set a faster priority" );
679 /*****************************************************************************
680 * vlc_thread_ready: tell the parent thread we were successfully spawned
681 *****************************************************************************/
682 void __vlc_thread_ready( vlc_object_t *p_this )
684 vlc_object_signal( p_this );
687 /*****************************************************************************
688 * vlc_thread_join: wait until a thread exits, inner version
689 *****************************************************************************/
690 void __vlc_thread_join( vlc_object_t *p_this, const char * psz_file, int i_line )
692 vlc_object_internals_t *p_priv = vlc_internals( p_this );
695 #if defined( LIBVLC_USE_PTHREAD )
696 /* Make sure we do return if we are calling vlc_thread_join()
697 * from the joined thread */
698 if (pthread_equal (pthread_self (), p_priv->thread_id))
699 i_ret = pthread_detach (p_priv->thread_id);
701 i_ret = pthread_join (p_priv->thread_id, NULL);
703 #elif defined( UNDER_CE ) || defined( WIN32 )
705 BOOL (WINAPI *OurGetThreadTimes)( HANDLE, FILETIME*, FILETIME*,
706 FILETIME*, FILETIME* );
707 FILETIME create_ft, exit_ft, kernel_ft, user_ft;
708 int64_t real_time, kernel_time, user_time;
712 ** object will close its thread handle when destroyed, duplicate it here
713 ** to be on the safe side
715 if( ! DuplicateHandle(GetCurrentProcess(),
721 DUPLICATE_SAME_ACCESS) )
723 p_priv->b_thread = false;
724 i_ret = GetLastError();
728 WaitForSingleObject( hThread, INFINITE );
730 #if defined( UNDER_CE )
731 hmodule = GetModuleHandle( _T("COREDLL") );
733 hmodule = GetModuleHandle( _T("KERNEL32") );
735 OurGetThreadTimes = (BOOL (WINAPI*)( HANDLE, FILETIME*, FILETIME*,
736 FILETIME*, FILETIME* ))
737 GetProcAddress( hmodule, _T("GetThreadTimes") );
739 if( OurGetThreadTimes &&
740 OurGetThreadTimes( hThread,
741 &create_ft, &exit_ft, &kernel_ft, &user_ft ) )
744 ((((int64_t)exit_ft.dwHighDateTime)<<32)| exit_ft.dwLowDateTime) -
745 ((((int64_t)create_ft.dwHighDateTime)<<32)| create_ft.dwLowDateTime);
749 ((((int64_t)kernel_ft.dwHighDateTime)<<32)|
750 kernel_ft.dwLowDateTime) / 10;
753 ((((int64_t)user_ft.dwHighDateTime)<<32)|
754 user_ft.dwLowDateTime) / 10;
756 msg_Dbg( p_this, "thread times: "
757 "real %"PRId64"m%fs, kernel %"PRId64"m%fs, user %"PRId64"m%fs",
758 real_time/60/1000000,
759 (double)((real_time%(60*1000000))/1000000.0),
760 kernel_time/60/1000000,
761 (double)((kernel_time%(60*1000000))/1000000.0),
762 user_time/60/1000000,
763 (double)((user_time%(60*1000000))/1000000.0) );
765 CloseHandle( hThread );
768 #elif defined( HAVE_KERNEL_SCHEDULER_H )
770 i_ret = (B_OK == wait_for_thread( p_priv->thread_id, &exit_value ));
777 msg_Err( p_this, "thread_join(%lu) failed at %s:%d (%m)",
778 (unsigned long)p_priv->thread_id, psz_file, i_line );
781 msg_Dbg( p_this, "thread %lu joined (%s:%d)",
782 (unsigned long)p_priv->thread_id, psz_file, i_line );
784 p_priv->b_thread = false;