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 *****************************************************************************/
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 );
67 * Object running the current thread
69 static vlc_threadvar_t thread_object_key;
71 vlc_object_t *vlc_threadobj (void)
73 return vlc_threadvar_get (&thread_object_key);
76 vlc_threadvar_t msg_context_global_key;
78 #if defined(LIBVLC_USE_PTHREAD)
79 static inline unsigned long vlc_threadid (void)
81 union { pthread_t th; unsigned long int i; } v = { };
82 v.th = pthread_self ();
87 # include <execinfo.h>
90 /*****************************************************************************
91 * vlc_thread_fatal: Report an error from the threading layer
92 *****************************************************************************
93 * This is mostly meant for debugging.
94 *****************************************************************************/
95 void vlc_pthread_fatal (const char *action, int error,
96 const char *file, unsigned line)
98 fprintf (stderr, "LibVLC fatal error %s in thread %lu at %s:%u: %d\n",
99 action, vlc_threadid (), file, line, error);
102 /* Sometimes strerror_r() crashes too, so make sure we print an error
103 * message before we invoke it */
105 /* Avoid the strerror_r() prototype brain damage in glibc */
107 dprintf (2, " Error message: %m at:\n");
110 int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
111 backtrace_symbols_fd (stack, len, 2);
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);
135 void vlc_pthread_fatal (const char *action, int error,
136 const char *file, unsigned line)
138 (void)action; (void)error; (void)file; (void)line;
143 /*****************************************************************************
144 * vlc_threads_init: initialize threads system
145 *****************************************************************************
146 * This function requires lazy initialization of a global lock in order to
147 * keep the library really thread-safe. Some architectures don't support this
148 * and thus do not guarantee the complete reentrancy.
149 *****************************************************************************/
150 int vlc_threads_init( void )
152 int i_ret = VLC_SUCCESS;
154 /* If we have lazy mutex initialization, use it. Otherwise, we just
155 * hope nothing wrong happens. */
156 #if defined( LIBVLC_USE_PTHREAD )
157 pthread_mutex_lock( &once_mutex );
160 if( i_initializations == 0 )
162 p_root = vlc_custom_create( NULL, sizeof( *p_root ),
163 VLC_OBJECT_GENERIC, "root" );
170 /* We should be safe now. Do all the initialization stuff we want. */
171 vlc_threadvar_create( &thread_object_key, NULL );
172 vlc_threadvar_create( &msg_context_global_key, msg_StackDestroy );
177 /* If we have lazy mutex initialization support, unlock the mutex.
178 * Otherwize, we are screwed. */
179 #if defined( LIBVLC_USE_PTHREAD )
180 pthread_mutex_unlock( &once_mutex );
186 /*****************************************************************************
187 * vlc_threads_end: stop threads system
188 *****************************************************************************
189 * FIXME: This function is far from being threadsafe.
190 *****************************************************************************/
191 void vlc_threads_end( void )
193 #if defined( LIBVLC_USE_PTHREAD )
194 pthread_mutex_lock( &once_mutex );
197 assert( i_initializations > 0 );
199 if( i_initializations == 1 )
201 vlc_object_release( p_root );
202 vlc_threadvar_delete( &msg_context_global_key );
203 vlc_threadvar_delete( &thread_object_key );
207 #if defined( LIBVLC_USE_PTHREAD )
208 pthread_mutex_unlock( &once_mutex );
212 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
213 /* This is not prototyped under glibc, though it exists. */
214 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
217 /*****************************************************************************
218 * vlc_mutex_init: initialize a mutex
219 *****************************************************************************/
220 int vlc_mutex_init( vlc_mutex_t *p_mutex )
222 #if defined( LIBVLC_USE_PTHREAD )
223 pthread_mutexattr_t attr;
226 pthread_mutexattr_init( &attr );
229 /* Create error-checking mutex to detect problems more easily. */
230 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
231 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
233 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
236 i_result = pthread_mutex_init( p_mutex, &attr );
237 pthread_mutexattr_destroy( &attr );
239 #elif defined( UNDER_CE )
240 InitializeCriticalSection( &p_mutex->csection );
243 #elif defined( WIN32 )
244 *p_mutex = CreateMutex( 0, FALSE, 0 );
245 return (*p_mutex != NULL) ? 0 : ENOMEM;
247 #elif defined( HAVE_KERNEL_SCHEDULER_H )
248 /* check the arguments and whether it's already been initialized */
249 if( p_mutex == NULL )
254 if( p_mutex->init == 9999 )
259 p_mutex->lock = create_sem( 1, "BeMutex" );
260 if( p_mutex->lock < B_NO_ERROR )
265 p_mutex->init = 9999;
271 /*****************************************************************************
272 * vlc_mutex_init: initialize a recursive mutex (Do not use)
273 *****************************************************************************/
274 int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
276 #if defined( LIBVLC_USE_PTHREAD )
277 pthread_mutexattr_t attr;
280 pthread_mutexattr_init( &attr );
281 # if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
282 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
284 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
286 i_result = pthread_mutex_init( p_mutex, &attr );
287 pthread_mutexattr_destroy( &attr );
289 #elif defined( WIN32 )
290 /* Create mutex returns a recursive mutex */
291 *p_mutex = CreateMutex( 0, FALSE, 0 );
292 return (*p_mutex != NULL) ? 0 : ENOMEM;
294 # error Unimplemented!
299 /*****************************************************************************
300 * vlc_mutex_destroy: destroy a mutex, inner version
301 *****************************************************************************/
302 void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
304 #if defined( LIBVLC_USE_PTHREAD )
305 int val = pthread_mutex_destroy( p_mutex );
306 VLC_THREAD_ASSERT ("destroying mutex");
308 #elif defined( UNDER_CE )
309 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
311 DeleteCriticalSection( &p_mutex->csection );
313 #elif defined( WIN32 )
314 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
316 CloseHandle( *p_mutex );
318 #elif defined( HAVE_KERNEL_SCHEDULER_H )
319 if( p_mutex->init == 9999 )
320 delete_sem( p_mutex->lock );
327 /*****************************************************************************
328 * vlc_cond_init: initialize a condition
329 *****************************************************************************/
330 int __vlc_cond_init( vlc_cond_t *p_condvar )
332 #if defined( LIBVLC_USE_PTHREAD )
333 pthread_condattr_t attr;
336 ret = pthread_condattr_init (&attr);
340 # if !defined (_POSIX_CLOCK_SELECTION)
341 /* Fairly outdated POSIX support (that was defined in 2001) */
342 # define _POSIX_CLOCK_SELECTION (-1)
344 # if (_POSIX_CLOCK_SELECTION >= 0)
345 /* NOTE: This must be the same clock as the one in mtime.c */
346 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
349 ret = pthread_cond_init (p_condvar, &attr);
350 pthread_condattr_destroy (&attr);
353 #elif defined( UNDER_CE ) || defined( WIN32 )
354 /* Initialize counter */
355 p_condvar->i_waiting_threads = 0;
357 /* Create an auto-reset event. */
358 p_condvar->event = CreateEvent( NULL, /* no security */
359 FALSE, /* auto-reset event */
360 FALSE, /* start non-signaled */
361 NULL ); /* unnamed */
362 return !p_condvar->event;
364 #elif defined( HAVE_KERNEL_SCHEDULER_H )
370 if( p_condvar->init == 9999 )
375 p_condvar->thread = -1;
376 p_condvar->init = 9999;
382 /*****************************************************************************
383 * vlc_cond_destroy: destroy a condition, inner version
384 *****************************************************************************/
385 void __vlc_cond_destroy( const char * psz_file, int i_line, vlc_cond_t *p_condvar )
387 #if defined( LIBVLC_USE_PTHREAD )
388 int val = pthread_cond_destroy( p_condvar );
389 VLC_THREAD_ASSERT ("destroying condition");
391 #elif defined( UNDER_CE ) || defined( WIN32 )
392 VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
394 CloseHandle( p_condvar->event );
396 #elif defined( HAVE_KERNEL_SCHEDULER_H )
402 /*****************************************************************************
403 * vlc_tls_create: create a thread-local variable
404 *****************************************************************************/
405 int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
409 #if defined( LIBVLC_USE_PTHREAD )
410 i_ret = pthread_key_create( p_tls, destr );
411 #elif defined( UNDER_CE )
413 #elif defined( WIN32 )
415 i_ret = (*p_tls == TLS_OUT_OF_INDEXES) ? EAGAIN : 0;
417 # error Unimplemented!
422 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
424 #if defined( LIBVLC_USE_PTHREAD )
425 pthread_key_delete (*p_tls);
426 #elif defined( UNDER_CE )
427 #elif defined( WIN32 )
430 # error Unimplemented!
434 struct vlc_thread_boot
436 void * (*entry) (void *);
437 vlc_object_t *object;
440 #if defined (LIBVLC_USE_PTHREAD)
441 # define THREAD_RTYPE void *
442 # define THREAD_RVAL NULL
443 #elif defined (WIN32)
444 # define THREAD_RTYPE __stdcall unsigned
445 # define THREAD_RVAL 0
448 static THREAD_RTYPE thread_entry (void *data)
450 vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
451 void *(*func) (void *) = ((struct vlc_thread_boot *)data)->entry;
454 vlc_threadvar_set (&thread_object_key, obj);
455 msg_Dbg (obj, "thread started");
457 msg_Dbg (obj, "thread ended");
461 /*****************************************************************************
462 * vlc_thread_create: create a thread, inner version
463 *****************************************************************************
464 * Note that i_priority is only taken into account on platforms supporting
465 * userland real-time priority threads.
466 *****************************************************************************/
467 int __vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
468 const char *psz_name, void * ( *func ) ( void * ),
469 int i_priority, bool b_wait )
472 vlc_object_internals_t *p_priv = vlc_internals( p_this );
474 struct vlc_thread_boot *boot = malloc (sizeof (*boot));
478 boot->object = p_this;
480 vlc_mutex_lock( &p_this->object_lock );
482 #if defined( LIBVLC_USE_PTHREAD )
483 sigset_t set, oldset;
485 /* We really don't want signals to (literaly) interrupt our blocking I/O
486 * system calls. SIGPIPE is especially bad, as it can be caused by remote
487 * peers through connected sockets. Generally, we cannot know which signals
488 * are handled by the main program. Also, external LibVLC bindings tend not
489 * to setup a proper signal mask before invoking LibVLC.
490 * Hence, we hereby block all signals, except those for which blocking is
491 * undefined, as listed below. Note that SIGKILL and SIGSTOP need not be
492 * listed (see the documentation for pthread_sigmask) here. */
494 sigdelset (&set, SIGFPE);
495 sigdelset (&set, SIGILL);
496 sigdelset (&set, SIGSEGV);
497 sigdelset (&set, SIGBUS);
498 pthread_sigmask (SIG_BLOCK, &set, &oldset);
500 i_ret = pthread_create( &p_priv->thread_id, NULL, thread_entry, boot );
501 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
504 if( config_GetInt( p_this, "rt-priority" ) > 0 )
507 int i_error, i_policy;
508 struct sched_param param;
510 memset( ¶m, 0, sizeof(struct sched_param) );
511 if( config_GetType( p_this, "rt-offset" ) )
512 i_priority += config_GetInt( p_this, "rt-offset" );
513 if( i_priority <= 0 )
515 param.sched_priority = (-1) * i_priority;
516 i_policy = SCHED_OTHER;
520 param.sched_priority = i_priority;
523 if( (i_error = pthread_setschedparam( p_priv->thread_id,
524 i_policy, ¶m )) )
527 msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
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;