Commit 0774c40b authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont

Rework threading:

 - lock/unlock/signal/wait/destroy functions cannot fail unless there is a bug,
   so have them return void rather than an unused int, and assert against bugs.
 - Fix a few corner case minor bugs.
 - Use fprintf() rather than msg_Err() to avoid infinite recursions.
parent 612a1f1d
......@@ -35,25 +35,17 @@
/*****************************************************************************
* Function definitions
*****************************************************************************/
VLC_EXPORT( void, vlc_threads_error, ( vlc_object_t *) );
VLC_EXPORT( int, __vlc_mutex_init, ( vlc_object_t *, vlc_mutex_t * ) );
VLC_EXPORT( int, __vlc_mutex_init_recursive, ( vlc_object_t *, vlc_mutex_t * ) );
VLC_EXPORT( int, __vlc_mutex_destroy, ( const char *, int, vlc_mutex_t * ) );
VLC_EXPORT( void, __vlc_mutex_destroy, ( const char *, int, vlc_mutex_t * ) );
VLC_EXPORT( int, __vlc_cond_init, ( vlc_object_t *, vlc_cond_t * ) );
VLC_EXPORT( int, __vlc_cond_destroy, ( const char *, int, vlc_cond_t * ) );
VLC_EXPORT( void, __vlc_cond_destroy, ( const char *, int, vlc_cond_t * ) );
VLC_EXPORT( int, __vlc_threadvar_create, (vlc_object_t *, vlc_threadvar_t * ) );
VLC_EXPORT( int, __vlc_thread_create, ( vlc_object_t *, const char *, int, const char *, void * ( * ) ( void * ), int, vlc_bool_t ) );
VLC_EXPORT( int, __vlc_thread_set_priority, ( vlc_object_t *, const char *, int, int ) );
VLC_EXPORT( void, __vlc_thread_ready, ( vlc_object_t * ) );
VLC_EXPORT( void, __vlc_thread_join, ( vlc_object_t *, const char *, int ) );
/*****************************************************************************
* vlc_threads_error: Signalize an error in the threading system
*****************************************************************************/
#ifdef NDEBUG
# define vlc_threads_error( P_THIS ) (void)0
#endif
/*****************************************************************************
* vlc_threads_init: initialize threads system
*****************************************************************************/
......@@ -85,71 +77,37 @@ VLC_EXPORT( void, __vlc_thread_join, ( vlc_object_t *, const char *, int ) );
__vlc_mutex_lock( __FILE__, __LINE__, P_MUTEX )
#if defined(LIBVLC_USE_PTHREAD)
static inline unsigned long int CAST_PTHREAD_TO_INT (pthread_t th)
{
union { pthread_t th; unsigned long int i; } v = { };
v.th = th;
return v.i;
}
VLC_EXPORT(void, vlc_pthread_fatal, (const char *action, int error, const char *file, unsigned line));
# define VLC_THREAD_ASSERT( action ) \
if (val) \
vlc_pthread_fatal (action, val, psz_file, i_line)
#else
# define VLC_THREAD_ASSERT (void)0
#endif
static inline int __vlc_mutex_lock( const char * psz_file, int i_line,
static inline void __vlc_mutex_lock( const char * psz_file, int i_line,
vlc_mutex_t * p_mutex )
{
int i_result;
/* In case of error : */
unsigned long int i_thread = 0;
#if defined( UNDER_CE )
EnterCriticalSection( &p_mutex->csection );
i_result = 0;
#elif defined( WIN32 )
if( p_mutex->mutex )
{
WaitForSingleObject( p_mutex->mutex, INFINITE );
}
else
{
EnterCriticalSection( &p_mutex->csection );
}
i_result = 0;
#elif defined( HAVE_KERNEL_SCHEDULER_H )
if( p_mutex == NULL )
{
i_result = B_BAD_VALUE;
}
else if( p_mutex->init < 2000 )
{
i_result = B_NO_INIT;
}
else
{
i_result = acquire_sem( p_mutex->lock );
}
acquire_sem( p_mutex->lock );
#elif defined(LIBVLC_USE_PTHREAD)
# define vlc_assert_locked( m ) \
assert (pthread_mutex_lock (&((m)->mutex)) == EDEADLK)
i_result = pthread_mutex_lock( &p_mutex->mutex );
if ( i_result )
{
i_thread = CAST_PTHREAD_TO_INT(pthread_self());
errno = i_result;
}
int val = pthread_mutex_lock( &p_mutex->mutex );
VLC_THREAD_ASSERT ("locking mutex");
#endif
if( i_result )
{
msg_Err( p_mutex->p_this,
"thread %li: mutex_lock failed at %s:%d (%d:%m)",
i_thread, psz_file, i_line, i_result );
vlc_threads_error( p_mutex->p_this );
}
return i_result;
}
#ifndef vlc_assert_locked
......@@ -162,62 +120,26 @@ static inline int __vlc_mutex_lock( const char * psz_file, int i_line,
#define vlc_mutex_unlock( P_MUTEX ) \
__vlc_mutex_unlock( __FILE__, __LINE__, P_MUTEX )
static inline int __vlc_mutex_unlock( const char * psz_file, int i_line,
static inline void __vlc_mutex_unlock( const char * psz_file, int i_line,
vlc_mutex_t *p_mutex )
{
int i_result;
/* In case of error : */
unsigned long int i_thread = 0;
#if defined( UNDER_CE )
LeaveCriticalSection( &p_mutex->csection );
i_result = 0;
#elif defined( WIN32 )
if( p_mutex->mutex )
{
ReleaseMutex( p_mutex->mutex );
}
else
{
LeaveCriticalSection( &p_mutex->csection );
}
i_result = 0;
#elif defined( HAVE_KERNEL_SCHEDULER_H )
if( p_mutex == NULL )
{
i_result = B_BAD_VALUE;
}
else if( p_mutex->init < 2000 )
{
i_result = B_NO_INIT;
}
else
{
release_sem( p_mutex->lock );
return B_OK;
}
release_sem( p_mutex->lock );
#elif defined(LIBVLC_USE_PTHREAD)
i_result = pthread_mutex_unlock( &p_mutex->mutex );
if ( i_result )
{
i_thread = CAST_PTHREAD_TO_INT(pthread_self());
errno = i_result;
}
int val = pthread_mutex_unlock( &p_mutex->mutex );
VLC_THREAD_ASSERT ("unlocking mutex");
#endif
if( i_result )
{
msg_Err( p_mutex->p_this,
"thread %li: mutex_unlock failed at %s:%d (%d:%m)",
i_thread, psz_file, i_line, i_result );
vlc_threads_error( p_mutex->p_this );
}
return i_result;
}
/*****************************************************************************
......@@ -238,16 +160,11 @@ static inline int __vlc_mutex_unlock( const char * psz_file, int i_line,
#define vlc_cond_signal( P_COND ) \
__vlc_cond_signal( __FILE__, __LINE__, P_COND )
static inline int __vlc_cond_signal( const char * psz_file, int i_line,
vlc_cond_t *p_condvar )
static inline void __vlc_cond_signal( const char * psz_file, int i_line,
vlc_cond_t *p_condvar )
{
int i_result;
/* In case of error : */
unsigned long int i_thread = 0;
#if defined( UNDER_CE )
PulseEvent( p_condvar->event );
i_result = 0;
#elif defined( WIN32 )
/* Release one waiting thread if one is available. */
......@@ -255,11 +172,9 @@ static inline int __vlc_cond_signal( const char * psz_file, int i_line,
* by a mutex. This will prevent another thread from stealing the signal */
if( !p_condvar->semaphore )
{
/*
** PulseEvent() only works if none of the waiting threads is suspended.
** this is particularily problematic under a debug session.
** as documented in http://support.microsoft.com/kb/q173260/
*/
/* PulseEvent() only works if none of the waiting threads is suspended.
* This is particularily problematic under a debug session.
* as documented in http://support.microsoft.com/kb/q173260/ */
PulseEvent( p_condvar->event );
}
else if( p_condvar->i_win9x_cv == 1 )
......@@ -293,64 +208,34 @@ static inline int __vlc_cond_signal( const char * psz_file, int i_line,
WaitForSingleObject( p_condvar->event, INFINITE );
}
}
i_result = 0;
#elif defined( HAVE_KERNEL_SCHEDULER_H )
if( p_condvar == NULL )
while( p_condvar->thread != -1 )
{
i_result = B_BAD_VALUE;
}
else if( p_condvar->init < 2000 )
{
i_result = B_NO_INIT;
}
else
{
while( p_condvar->thread != -1 )
thread_info info;
if( get_thread_info(p_condvar->thread, &info) == B_BAD_VALUE )
return;
if( info.state != B_THREAD_SUSPENDED )
{
thread_info info;
if( get_thread_info(p_condvar->thread, &info) == B_BAD_VALUE )
{
return 0;
}
if( info.state != B_THREAD_SUSPENDED )
{
/* The waiting thread is not suspended so it could
* have been interrupted beetwen the unlock and the
* suspend_thread line. That is why we sleep a little
* before retesting p_condver->thread. */
snooze( 10000 );
}
else
{
/* Ok, we have to wake up that thread */
resume_thread( p_condvar->thread );
return 0;
}
/* The waiting thread is not suspended so it could
* have been interrupted beetwen the unlock and the
* suspend_thread line. That is why we sleep a little
* before retesting p_condver->thread. */
snooze( 10000 );
}
else
{
/* Ok, we have to wake up that thread */
resume_thread( p_condvar->thread );
}
i_result = 0;
}
#elif defined(LIBVLC_USE_PTHREAD)
i_result = pthread_cond_signal( &p_condvar->cond );
if ( i_result )
{
i_thread = CAST_PTHREAD_TO_INT(pthread_self());
errno = i_result;
}
int val = pthread_cond_signal( &p_condvar->cond );
VLC_THREAD_ASSERT ("signaling condition variable");
#endif
if( i_result )
{
msg_Err( p_condvar->p_this,
"thread %li: cond_signal failed at %s:%d (%d:%m)",
i_thread, psz_file, i_line, i_result );
vlc_threads_error( p_condvar->p_this );
}
return i_result;
}
/*****************************************************************************
......@@ -359,13 +244,9 @@ static inline int __vlc_cond_signal( const char * psz_file, int i_line,
#define vlc_cond_wait( P_COND, P_MUTEX ) \
__vlc_cond_wait( __FILE__, __LINE__, P_COND, P_MUTEX )
static inline int __vlc_cond_wait( const char * psz_file, int i_line,
vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex )
static inline void __vlc_cond_wait( const char * psz_file, int i_line,
vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex )
{
int i_result;
/* In case of error : */
unsigned long int i_thread = 0;
#if defined( UNDER_CE )
p_condvar->i_waiting_threads++;
LeaveCriticalSection( &p_mutex->csection );
......@@ -375,8 +256,6 @@ static inline int __vlc_cond_wait( const char * psz_file, int i_line,
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
i_result = 0;
#elif defined( WIN32 )
if( !p_condvar->semaphore )
{
......@@ -451,22 +330,7 @@ static inline int __vlc_cond_wait( const char * psz_file, int i_line,
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
i_result = 0;
#elif defined( HAVE_KERNEL_SCHEDULER_H )
if( p_condvar == NULL )
{
i_result = B_BAD_VALUE;
}
else if( p_mutex == NULL )
{
i_result = B_BAD_VALUE;
}
else if( p_condvar->init < 2000 )
{
i_result = B_NO_INIT;
}
/* The p_condvar->thread var is initialized before the unlock because
* it enables to identify when the thread is interrupted beetwen the
* unlock line and the suspend_thread line */
......@@ -476,27 +340,12 @@ static inline int __vlc_cond_wait( const char * psz_file, int i_line,
p_condvar->thread = -1;
vlc_mutex_lock( p_mutex );
i_result = 0;
#elif defined(LIBVLC_USE_PTHREAD)
i_result = pthread_cond_wait( &p_condvar->cond, &p_mutex->mutex );
if ( i_result )
{
i_thread = CAST_PTHREAD_TO_INT(pthread_self());
errno = i_result;
}
int val = pthread_cond_wait( &p_condvar->cond, &p_mutex->mutex );
VLC_THREAD_ASSERT ("waiting on condition");
#endif
if( i_result )
{
msg_Err( p_condvar->p_this,
"thread %li: cond_wait failed at %s:%d (%d:%m)",
i_thread, psz_file, i_line, i_result );
vlc_threads_error( p_condvar->p_this );
}
return i_result;
}
......@@ -513,9 +362,6 @@ static inline int __vlc_cond_timedwait( const char * psz_file, int i_line,
vlc_mutex_t *p_mutex,
mtime_t deadline )
{
int i_res;
unsigned long int i_thread = 0;
#if defined( UNDER_CE )
mtime_t delay_ms = (deadline - mdate())/1000;
......@@ -531,9 +377,8 @@ static inline int __vlc_cond_timedwait( const char * psz_file, int i_line,
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
i_res = (int)result;
if(result == WAIT_TIMEOUT)
return WAIT_TIMEOUT; /* this error is perfectly normal */
return ETIMEDOUT; /* this error is perfectly normal */
#elif defined( WIN32 )
DWORD result;
......@@ -623,37 +468,23 @@ static inline int __vlc_cond_timedwait( const char * psz_file, int i_line,
/* Reacquire the mutex before returning. */
vlc_mutex_lock( p_mutex );
if(result == WAIT_TIMEOUT)
return WAIT_TIMEOUT; /* this error is perfectly normal */
i_res = (int)result;
return ETIMEDOUT; /* this error is perfectly normal */
#elif defined( HAVE_KERNEL_SCHEDULER_H )
# error Unimplemented
#elif defined(LIBVLC_USE_PTHREAD)
lldiv_t d = lldiv( deadline, 1000000 );
struct timespec ts = { d.quot, d.rem * 1000 };
i_res = pthread_cond_timedwait( &p_condvar->cond, &p_mutex->mutex, &ts );
if( i_res == ETIMEDOUT )
int val = pthread_cond_timedwait (&p_condvar->cond, &p_mutex->mutex, &ts);
if (val == ETIMEDOUT)
return ETIMEDOUT; /* this error is perfectly normal */
else
if ( i_res ) /* other errors = bug */
{
i_thread = CAST_PTHREAD_TO_INT(pthread_self());
errno = i_res;
}
VLC_THREAD_ASSERT ("timed-waiting on condition");
#endif
if( i_res )
{
msg_Err( p_condvar->p_this,
"thread %li: cond_wait failed at %s:%d (%d:%m)",
i_thread, psz_file, i_line, i_res );
vlc_threads_error( p_condvar->p_this );
}
return i_res;
return 0;
}
/*****************************************************************************
......@@ -726,25 +557,28 @@ static inline int vlc_spin_init (vlc_spinlock_t *spin)
/**
* Acquires a spinlock.
*/
static inline int vlc_spin_lock (vlc_spinlock_t *spin)
static inline void vlc_spin_lock (vlc_spinlock_t *spin)
{
return pthread_spin_lock (&spin->spin);
int val = pthread_spin_lock (&spin->spin);
assert (val == 0);
}
/**
* Releases a spinlock.
*/
static inline int vlc_spin_unlock (vlc_spinlock_t *spin)
static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
{
return pthread_spin_unlock (&spin->spin);
int val = pthread_spin_unlock (&spin->spin);
assert (val == 0);
}
/**
* Deinitializes a spinlock.
*/
static inline int vlc_spin_destroy (vlc_spinlock_t *spin)
static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
{
return pthread_spin_destroy (&spin->spin);
int val = pthread_spin_destroy (&spin->spin);
assert (val == 0);
}
#elif defined( WIN32 )
......@@ -762,25 +596,23 @@ static inline int vlc_spin_init (vlc_spinlock_t *spin)
/**
* Acquires a spinlock.
*/
static inline int vlc_spin_lock (vlc_spinlock_t *spin)
static inline void vlc_spin_lock (vlc_spinlock_t *spin)
{
EnterCriticalSection(spin);
return 0;
}
/**
* Releases a spinlock.
*/
static inline int vlc_spin_unlock (vlc_spinlock_t *spin)
static inline void vlc_spin_unlock (vlc_spinlock_t *spin)
{
LeaveCriticalSection(spin);
return 0;
}
/**
* Deinitializes a spinlock.
*/
static inline int vlc_spin_destroy (vlc_spinlock_t *spin)
static inline void vlc_spin_destroy (vlc_spinlock_t *spin)
{
DeleteCriticalSection(spin);
return 0;
......@@ -789,7 +621,6 @@ static inline int vlc_spin_destroy (vlc_spinlock_t *spin)
#else
/* Fallback to plain mutexes if spinlocks are not available */
typedef vlc_mutex_t vlc_spinlock_t;
......
......@@ -432,6 +432,7 @@ __vlc_object_waitpipe
__vlc_object_yield
vlc_opendir
vlc_parse_cmdline
vlc_pthread_fatal
vlc_rand_bytes
vlc_readdir
vlc_scandir
......@@ -448,7 +449,6 @@ vlc_submodule_create
__vlc_thread_create
__vlc_thread_join
__vlc_thread_ready
vlc_threads_error
__vlc_thread_set_priority
__vlc_threadvar_create
vlc_ureduce
......
......@@ -78,20 +78,40 @@ static pthread_mutex_t once_mutex = PTHREAD_MUTEX_INITIALIZER;
vlc_threadvar_t msg_context_global_key;
#ifndef NDEBUG
#if defined(LIBVLC_USE_PTHREAD)
static inline unsigned long vlc_threadid (void)
{
union { pthread_t th; unsigned long int i; } v = { };
v.th = pthread_self ();
return v.i;
}
/*****************************************************************************
* vlc_threads_error: Report an error from the threading mecanism
* vlc_thread_fatal: Report an error from the threading layer
*****************************************************************************
* This is especially useful to debug those errors, as this is a nice symbol
* on which you can break.
* This is mostly meant for debugging.
*****************************************************************************/
void vlc_threads_error( vlc_object_t *p_this )
void vlc_pthread_fatal (const char *action, int error,
const char *file, unsigned line)
{
msg_Err( p_this, "Error detected. Put a breakpoint in '%s' to debug.",
__func__ );
char buf[1000];
const char *msg;
fprintf (stderr, "LibVLC fatal error %s in thread %lu at %s:%u: %d\n",
action, vlc_threadid (), file, line, error);
fflush (stderr);
/* Sometimes strerror_r() crashes too, so make sure we print an error
* message before we invoke it */
msg = strerror_r (error, buf, sizeof (buf));
fprintf (stderr, " %s\n", msg ? msg : "(null)");
fflush (stderr);
abort ();
}
#endif
/*****************************************************************************
* vlc_threads_init: initialize threads system
*****************************************************************************
......@@ -309,6 +329,8 @@ int __vlc_mutex_init( vlc_object_t *p_this, vlc_mutex_t *p_mutex )
*****************************************************************************/
int __vlc_mutex_init_recursive( vlc_object_t *p_this, vlc_mutex_t *p_mutex )
{
p_mutex->p_this = p_this;
#if defined( WIN32 )
/* Create mutex returns a recursive mutex */
p_mutex->mutex = CreateMutex( 0, FALSE, 0 );
......@@ -341,54 +363,28 @@ int __vlc_mutex_init_recursive( vlc_object_t *p_this, vlc_mutex_t *p_mutex )
/*****************************************************************************
* vlc_mutex_destroy: destroy a mutex, inner version
*****************************************************************************/
int __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
{
int i_result;
/* In case of error : */
int i_thread = -1;
#if defined( UNDER_CE )
DeleteCriticalSection( &p_mutex->csection );
return 0;
#elif defined( WIN32 )
if( p_mutex->mutex )
{
CloseHandle( p_mutex->mutex );
}
else
{
DeleteCriticalSection( &p_mutex->csection );
}
return 0;
#elif defined( HAVE_KERNEL_SCHEDULER_H )
if( p_mutex->init == 9999 )
{
delete_sem( p_mutex->lock );
}
p_mutex->init = 0;
return B_OK;
#elif defined( LIBVLC_USE_PTHREAD )
i_result = pthread_mutex_destroy( &p_mutex->mutex );
if( i_result )
{
i_thread = CAST_PTHREAD_TO_INT(pthread_self());
errno = i_result;
}
int val = pthread_mutex_destroy( &p_mutex->mutex );
VLC_THREAD_ASSERT ("destroying mutex");
#endif
if( i_result )
{
msg_Err( p_mutex->p_this,
"thread %d: mutex_destroy failed at %s:%d (%d:%m)",
i_thread, psz_file, i_line, i_result );
vlc_threads_error( p_mutex->p_this );
}
return i_result;
}
/*****************************************************************************
......@@ -490,47 +486,31 @@ int __vlc_cond_init( vlc_object_t *p_this, vlc_cond_t *p_condvar )
/*****************************************************************************
* vlc_cond_destroy: destroy a condition, inner version