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 )
51 static pthread_mutex_t once_mutex = PTHREAD_MUTEX_INITIALIZER;
55 * Global process-wide VLC object.
56 * Contains inter-instance data, such as the module cache and global mutexes.
58 static libvlc_global_data_t *p_root;
60 libvlc_global_data_t *vlc_global( void )
62 assert( i_initializations > 0 );
68 * Object running the current thread
70 static vlc_threadvar_t thread_object_key;
72 vlc_object_t *vlc_threadobj (void)
74 return vlc_threadvar_get (&thread_object_key);
78 vlc_threadvar_t msg_context_global_key;
80 #if defined(LIBVLC_USE_PTHREAD)
81 static inline unsigned long vlc_threadid (void)
83 union { pthread_t th; unsigned long int i; } v = { };
84 v.th = pthread_self ();
88 #if defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE)
89 # include <execinfo.h>
92 /*****************************************************************************
93 * vlc_thread_fatal: Report an error from the threading layer
94 *****************************************************************************
95 * This is mostly meant for debugging.
96 *****************************************************************************/
97 void vlc_pthread_fatal (const char *action, int error,
98 const char *file, unsigned line)
100 fprintf (stderr, "LibVLC fatal error %s in thread %lu at %s:%u: %d\n",
101 action, vlc_threadid (), file, line, error);
104 /* Sometimes strerror_r() crashes too, so make sure we print an error
105 * message before we invoke it */
107 /* Avoid the strerror_r() prototype brain damage in glibc */
109 dprintf (2, " Error message: %m at:\n");
114 switch (strerror_r (error, buf, sizeof (buf)))
119 case ERANGE: /* should never happen */
120 msg = "unknwon (too big to display)";
123 msg = "unknown (invalid error number)";
126 fprintf (stderr, " Error message: %s\n", msg);
130 #ifdef HAVE_BACKTRACE
132 int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
133 backtrace_symbols_fd (stack, len, 2);
139 void vlc_pthread_fatal (const char *action, int error,
140 const char *file, unsigned line)
142 (void)action; (void)error; (void)file; (void)line;
147 /*****************************************************************************
148 * vlc_threads_init: initialize threads system
149 *****************************************************************************
150 * This function requires lazy initialization of a global lock in order to
151 * keep the library really thread-safe. Some architectures don't support this
152 * and thus do not guarantee the complete reentrancy.
153 *****************************************************************************/
154 int vlc_threads_init( void )
156 int i_ret = VLC_SUCCESS;
158 /* If we have lazy mutex initialization, use it. Otherwise, we just
159 * hope nothing wrong happens. */
160 #if defined( LIBVLC_USE_PTHREAD )
161 pthread_mutex_lock( &once_mutex );
164 if( i_initializations == 0 )
166 p_root = vlc_custom_create( NULL, sizeof( *p_root ),
167 VLC_OBJECT_GENERIC, "root" );
174 /* We should be safe now. Do all the initialization stuff we want. */
176 vlc_threadvar_create( &thread_object_key, NULL );
178 vlc_threadvar_create( &msg_context_global_key, msg_StackDestroy );
183 /* If we have lazy mutex initialization support, unlock the mutex.
184 * Otherwize, we are screwed. */
185 #if defined( LIBVLC_USE_PTHREAD )
186 pthread_mutex_unlock( &once_mutex );
192 /*****************************************************************************
193 * vlc_threads_end: stop threads system
194 *****************************************************************************
195 * FIXME: This function is far from being threadsafe.
196 *****************************************************************************/
197 void vlc_threads_end( void )
199 #if defined( LIBVLC_USE_PTHREAD )
200 pthread_mutex_lock( &once_mutex );
203 assert( i_initializations > 0 );
205 if( i_initializations == 1 )
207 vlc_object_release( p_root );
208 vlc_threadvar_delete( &msg_context_global_key );
210 vlc_threadvar_delete( &thread_object_key );
215 #if defined( LIBVLC_USE_PTHREAD )
216 pthread_mutex_unlock( &once_mutex );
220 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
221 /* This is not prototyped under glibc, though it exists. */
222 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
225 /*****************************************************************************
226 * vlc_mutex_init: initialize a mutex
227 *****************************************************************************/
228 int vlc_mutex_init( vlc_mutex_t *p_mutex )
230 #if defined( LIBVLC_USE_PTHREAD )
231 pthread_mutexattr_t attr;
234 pthread_mutexattr_init( &attr );
237 /* Create error-checking mutex to detect problems more easily. */
238 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
239 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
241 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
244 i_result = pthread_mutex_init( p_mutex, &attr );
245 pthread_mutexattr_destroy( &attr );
247 #elif defined( UNDER_CE )
248 InitializeCriticalSection( &p_mutex->csection );
251 #elif defined( WIN32 )
252 *p_mutex = CreateMutex( 0, FALSE, 0 );
253 return (*p_mutex != NULL) ? 0 : ENOMEM;
255 #elif defined( HAVE_KERNEL_SCHEDULER_H )
256 /* check the arguments and whether it's already been initialized */
257 if( p_mutex == NULL )
262 if( p_mutex->init == 9999 )
267 p_mutex->lock = create_sem( 1, "BeMutex" );
268 if( p_mutex->lock < B_NO_ERROR )
273 p_mutex->init = 9999;
279 /*****************************************************************************
280 * vlc_mutex_init: initialize a recursive mutex (Do not use)
281 *****************************************************************************/
282 int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
284 #if defined( LIBVLC_USE_PTHREAD )
285 pthread_mutexattr_t attr;
288 pthread_mutexattr_init( &attr );
289 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
290 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
292 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
294 i_result = pthread_mutex_init( p_mutex, &attr );
295 pthread_mutexattr_destroy( &attr );
297 #elif defined( WIN32 )
298 /* Create mutex returns a recursive mutex */
299 *p_mutex = CreateMutex( 0, FALSE, 0 );
300 return (*p_mutex != NULL) ? 0 : ENOMEM;
302 # error Unimplemented!
307 /*****************************************************************************
308 * vlc_mutex_destroy: destroy a mutex, inner version
309 *****************************************************************************/
310 void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
312 #if defined( LIBVLC_USE_PTHREAD )
313 int val = pthread_mutex_destroy( p_mutex );
314 VLC_THREAD_ASSERT ("destroying mutex");
316 #elif defined( UNDER_CE )
317 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
319 DeleteCriticalSection( &p_mutex->csection );
321 #elif defined( WIN32 )
322 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
324 CloseHandle( *p_mutex );
326 #elif defined( HAVE_KERNEL_SCHEDULER_H )
327 if( p_mutex->init == 9999 )
328 delete_sem( p_mutex->lock );
335 /*****************************************************************************
336 * vlc_cond_init: initialize a condition
337 *****************************************************************************/
338 int __vlc_cond_init( vlc_cond_t *p_condvar )
340 #if defined( LIBVLC_USE_PTHREAD )
341 pthread_condattr_t attr;
344 ret = pthread_condattr_init (&attr);
348 # if !defined (_POSIX_CLOCK_SELECTION)
349 /* Fairly outdated POSIX support (that was defined in 2001) */
350 # define _POSIX_CLOCK_SELECTION (-1)
352 # if (_POSIX_CLOCK_SELECTION >= 0)
353 /* NOTE: This must be the same clock as the one in mtime.c */
354 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
357 ret = pthread_cond_init (p_condvar, &attr);
358 pthread_condattr_destroy (&attr);
361 #elif defined( UNDER_CE ) || defined( WIN32 )
362 /* Initialize counter */
363 p_condvar->i_waiting_threads = 0;
365 /* Create an auto-reset event. */
366 p_condvar->event = CreateEvent( NULL, /* no security */
367 FALSE, /* auto-reset event */
368 FALSE, /* start non-signaled */
369 NULL ); /* unnamed */
370 return !p_condvar->event;
372 #elif defined( HAVE_KERNEL_SCHEDULER_H )
378 if( p_condvar->init == 9999 )
383 p_condvar->thread = -1;
384 p_condvar->init = 9999;
390 /*****************************************************************************
391 * vlc_cond_destroy: destroy a condition, inner version
392 *****************************************************************************/
393 void __vlc_cond_destroy( const char * psz_file, int i_line, vlc_cond_t *p_condvar )
395 #if defined( LIBVLC_USE_PTHREAD )
396 int val = pthread_cond_destroy( p_condvar );
397 VLC_THREAD_ASSERT ("destroying condition");
399 #elif defined( UNDER_CE ) || defined( WIN32 )
400 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
402 CloseHandle( p_condvar->event );
404 #elif defined( HAVE_KERNEL_SCHEDULER_H )
410 /*****************************************************************************
411 * vlc_tls_create: create a thread-local variable
412 *****************************************************************************/
413 int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
417 #if defined( LIBVLC_USE_PTHREAD )
418 i_ret = pthread_key_create( p_tls, destr );
419 #elif defined( UNDER_CE )
421 #elif defined( WIN32 )
423 i_ret = (*p_tls == TLS_OUT_OF_INDEXES) ? EAGAIN : 0;
425 # error Unimplemented!
430 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
432 #if defined( LIBVLC_USE_PTHREAD )
433 pthread_key_delete (*p_tls);
434 #elif defined( UNDER_CE )
435 #elif defined( WIN32 )
438 # error Unimplemented!
442 struct vlc_thread_boot
444 void * (*entry) (void *);
445 vlc_object_t *object;
448 #if defined (LIBVLC_USE_PTHREAD)
449 # define THREAD_RTYPE void *
450 # define THREAD_RVAL NULL
451 #elif defined (WIN32)
452 # define THREAD_RTYPE __stdcall unsigned
453 # define THREAD_RVAL 0
456 static THREAD_RTYPE thread_entry (void *data)
458 vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
459 void *(*func) (void *) = ((struct vlc_thread_boot *)data)->entry;
463 vlc_threadvar_set (&thread_object_key, obj);
465 msg_Dbg (obj, "thread started");
467 msg_Dbg (obj, "thread ended");
471 /*****************************************************************************
472 * vlc_thread_create: create a thread, inner version
473 *****************************************************************************
474 * Note that i_priority is only taken into account on platforms supporting
475 * userland real-time priority threads.
476 *****************************************************************************/
477 int __vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
478 const char *psz_name, void * ( *func ) ( void * ),
479 int i_priority, bool b_wait )
482 vlc_object_internals_t *p_priv = vlc_internals( p_this );
484 struct vlc_thread_boot *boot = malloc (sizeof (*boot));
488 boot->object = p_this;
490 vlc_mutex_lock( &p_this->object_lock );
492 #if defined( LIBVLC_USE_PTHREAD )
494 pthread_attr_init (&attr);
496 sigset_t set, oldset;
497 /* We really don't want signals to (literaly) interrupt our blocking I/O
498 * system calls. SIGPIPE is especially bad, as it can be caused by remote
499 * peers through connected sockets. Generally, we cannot know which signals
500 * are handled by the main program. Also, external LibVLC bindings tend not
501 * to setup a proper signal mask before invoking LibVLC.
502 * Hence, we hereby block all signals, except those for which blocking is
503 * undefined, as listed below. Note that SIGKILL and SIGSTOP need not be
504 * listed (see the documentation for pthread_sigmask) here. */
506 sigdelset (&set, SIGFPE);
507 sigdelset (&set, SIGILL);
508 sigdelset (&set, SIGSEGV);
509 sigdelset (&set, SIGBUS);
510 pthread_sigmask (SIG_BLOCK, &set, &oldset);
513 if( config_GetInt( p_this, "rt-priority" ) > 0 )
516 /* Hack to avoid error msg */
517 if( config_GetType( p_this, "rt-offset" ) )
518 i_priority += config_GetInt( p_this, "rt-offset" );
519 if( i_priority <= 0 )
521 struct sched_param param = { .sched_priority = -i_priority, };
522 pthread_attr_setschedpolicy (&attr, SCHED_OTHER);
523 pthread_attr_setschedparam (&attr, ¶m);
527 struct sched_param param = { .sched_priority = +i_priority, };
528 pthread_attr_setschedpolicy (&attr, SCHED_OTHER);
529 pthread_attr_setschedparam (&attr, ¶m);
533 i_ret = pthread_create( &p_priv->thread_id, &attr, thread_entry, boot );
534 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
535 pthread_attr_destroy (&attr);
537 #elif defined( WIN32 ) || defined( UNDER_CE )
539 /* When using the MSVCRT C library you have to use the _beginthreadex
540 * function instead of CreateThread, otherwise you'll end up with
541 * memory leaks and the signal functions not working (see Microsoft
542 * Knowledge Base, article 104641) */
543 #if defined( UNDER_CE )
544 HANDLE hThread = CreateThread( NULL, 0, thread_entry,
545 (LPVOID)boot, CREATE_SUSPENDED,
548 HANDLE hThread = (HANDLE)(uintptr_t)
549 _beginthreadex( NULL, 0, thread_entry, boot,
550 CREATE_SUSPENDED, NULL );
552 p_priv->thread_id = hThread;
553 ResumeThread(hThread);
556 i_ret = ( p_priv->thread_id ? 0 : errno );
558 if( !i_ret && i_priority )
560 if( !SetThreadPriority(p_priv->thread_id, i_priority) )
562 msg_Warn( p_this, "couldn't set a faster priority" );
567 #elif defined( HAVE_KERNEL_SCHEDULER_H )
568 p_priv->thread_id = spawn_thread( (thread_func)thread_entry, psz_name,
569 i_priority, p_data );
570 i_ret = resume_thread( p_priv->thread_id );
578 msg_Dbg( p_this, "waiting for thread completion" );
579 vlc_object_wait( p_this );
582 p_priv->b_thread = true;
583 msg_Dbg( p_this, "thread %lu (%s) created at priority %d (%s:%d)",
584 (unsigned long)p_priv->thread_id, psz_name, i_priority,
590 msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
591 psz_name, psz_file, i_line );
594 vlc_mutex_unlock( &p_this->object_lock );
598 /*****************************************************************************
599 * vlc_thread_set_priority: set the priority of the current thread when we
600 * couldn't set it in vlc_thread_create (for instance for the main thread)
601 *****************************************************************************/
602 int __vlc_thread_set_priority( vlc_object_t *p_this, const char * psz_file,
603 int i_line, int i_priority )
605 vlc_object_internals_t *p_priv = vlc_internals( p_this );
607 #if defined( LIBVLC_USE_PTHREAD )
609 if( config_GetInt( p_this, "rt-priority" ) > 0 )
612 int i_error, i_policy;
613 struct sched_param param;
615 memset( ¶m, 0, sizeof(struct sched_param) );
616 if( config_GetType( p_this, "rt-offset" ) )
617 i_priority += config_GetInt( p_this, "rt-offset" );
618 if( i_priority <= 0 )
620 param.sched_priority = (-1) * i_priority;
621 i_policy = SCHED_OTHER;
625 param.sched_priority = i_priority;
628 if( !p_priv->thread_id )
629 p_priv->thread_id = pthread_self();
630 if( (i_error = pthread_setschedparam( p_priv->thread_id,
631 i_policy, ¶m )) )
634 msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
640 #elif defined( WIN32 ) || defined( UNDER_CE )
641 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
643 if( !p_priv->thread_id )
644 p_priv->thread_id = GetCurrentThread();
645 if( !SetThreadPriority(p_priv->thread_id, i_priority) )
647 msg_Warn( p_this, "couldn't set a faster priority" );
656 /*****************************************************************************
657 * vlc_thread_ready: tell the parent thread we were successfully spawned
658 *****************************************************************************/
659 void __vlc_thread_ready( vlc_object_t *p_this )
661 vlc_object_signal( p_this );
664 /*****************************************************************************
665 * vlc_thread_join: wait until a thread exits, inner version
666 *****************************************************************************/
667 void __vlc_thread_join( vlc_object_t *p_this, const char * psz_file, int i_line )
669 vlc_object_internals_t *p_priv = vlc_internals( p_this );
672 #if defined( LIBVLC_USE_PTHREAD )
673 /* Make sure we do return if we are calling vlc_thread_join()
674 * from the joined thread */
675 if (pthread_equal (pthread_self (), p_priv->thread_id))
676 i_ret = pthread_detach (p_priv->thread_id);
678 i_ret = pthread_join (p_priv->thread_id, NULL);
680 #elif defined( UNDER_CE ) || defined( WIN32 )
682 BOOL (WINAPI *OurGetThreadTimes)( HANDLE, FILETIME*, FILETIME*,
683 FILETIME*, FILETIME* );
684 FILETIME create_ft, exit_ft, kernel_ft, user_ft;
685 int64_t real_time, kernel_time, user_time;
689 ** object will close its thread handle when destroyed, duplicate it here
690 ** to be on the safe side
692 if( ! DuplicateHandle(GetCurrentProcess(),
698 DUPLICATE_SAME_ACCESS) )
700 p_priv->b_thread = false;
701 i_ret = GetLastError();
705 WaitForSingleObject( hThread, INFINITE );
707 #if defined( UNDER_CE )
708 hmodule = GetModuleHandle( _T("COREDLL") );
710 hmodule = GetModuleHandle( _T("KERNEL32") );
712 OurGetThreadTimes = (BOOL (WINAPI*)( HANDLE, FILETIME*, FILETIME*,
713 FILETIME*, FILETIME* ))
714 GetProcAddress( hmodule, _T("GetThreadTimes") );
716 if( OurGetThreadTimes &&
717 OurGetThreadTimes( hThread,
718 &create_ft, &exit_ft, &kernel_ft, &user_ft ) )
721 ((((int64_t)exit_ft.dwHighDateTime)<<32)| exit_ft.dwLowDateTime) -
722 ((((int64_t)create_ft.dwHighDateTime)<<32)| create_ft.dwLowDateTime);
726 ((((int64_t)kernel_ft.dwHighDateTime)<<32)|
727 kernel_ft.dwLowDateTime) / 10;
730 ((((int64_t)user_ft.dwHighDateTime)<<32)|
731 user_ft.dwLowDateTime) / 10;
733 msg_Dbg( p_this, "thread times: "
734 "real %"PRId64"m%fs, kernel %"PRId64"m%fs, user %"PRId64"m%fs",
735 real_time/60/1000000,
736 (double)((real_time%(60*1000000))/1000000.0),
737 kernel_time/60/1000000,
738 (double)((kernel_time%(60*1000000))/1000000.0),
739 user_time/60/1000000,
740 (double)((user_time%(60*1000000))/1000000.0) );
742 CloseHandle( hThread );
745 #elif defined( HAVE_KERNEL_SCHEDULER_H )
747 i_ret = (B_OK == wait_for_thread( p_priv->thread_id, &exit_value ));
754 msg_Err( p_this, "thread_join(%lu) failed at %s:%d (%m)",
755 (unsigned long)p_priv->thread_id, psz_file, i_line );
758 msg_Dbg( p_this, "thread %lu joined (%s:%d)",
759 (unsigned long)p_priv->thread_id, psz_file, i_line );
761 p_priv->b_thread = false;