/**
* 11.4.2 Initializing and Destroying a Condition Variable,
* P1003.1c/Draft 10, p. 87
*/
int pthread_cond_destroy(
pthread_cond_t *cond
)
{
POSIX_Condition_variables_Control *the_cond;
Objects_Locations location;
the_cond = _POSIX_Condition_variables_Get( cond, &location );
switch ( location ) {
case OBJECTS_LOCAL:
if ( _Thread_queue_First( &the_cond->Wait_queue ) ) {
_Thread_Enable_dispatch();
return EBUSY;
}
_Objects_Close(
&_POSIX_Condition_variables_Information,
&the_cond->Object
);
_POSIX_Condition_variables_Free( the_cond );
_Thread_Enable_dispatch();
return 0;
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE:
#endif
case OBJECTS_ERROR:
break;
}
return EINVAL;
}
void _Region_Process_queue(
Region_Control *the_region
)
{
Thread_Control *the_thread;
void *the_segment;
/*
* Switch from using the memory allocation mutex to using a
* dispatching disabled critical section. We have to do this
* because this thread may unblock one or more threads that were
* waiting on memory.
*
* NOTE: Be sure to disable dispatching before unlocking the mutex
* since we do not want to open a window where a context
* switch could occur.
*/
_Thread_Disable_dispatch();
_RTEMS_Unlock_allocator();
/*
* NOTE: The following loop is O(n) where n is the number of
* threads whose memory request is satisfied.
*/
for ( ; ; ) {
the_thread = _Thread_queue_First( &the_region->Wait_queue );
if ( the_thread == NULL )
break;
the_segment = (void **) _Region_Allocate_segment(
the_region,
the_thread->Wait.count
);
if ( the_segment == NULL )
break;
*(void **)the_thread->Wait.return_argument = the_segment;
the_region->number_of_used_blocks += 1;
_Thread_queue_Extract( &the_region->Wait_queue, the_thread );
the_thread->Wait.return_code = RTEMS_SUCCESSFUL;
}
_Thread_Enable_dispatch();
}
/**
* 11.4.2 Initializing and Destroying a Condition Variable,
* P1003.1c/Draft 10, p. 87
*/
int pthread_cond_destroy(
pthread_cond_t *cond
)
{
POSIX_Condition_variables_Control *the_cond;
Objects_Locations location;
_Objects_Allocator_lock();
the_cond = _POSIX_Condition_variables_Get( cond, &location );
switch ( location ) {
case OBJECTS_LOCAL:
if (
_Thread_queue_First(
&the_cond->Wait_queue,
POSIX_CONDITION_VARIABLES_TQ_OPERATIONS
)
) {
_Objects_Put( &the_cond->Object );
_Objects_Allocator_unlock();
return EBUSY;
}
_Objects_Close(
&_POSIX_Condition_variables_Information,
&the_cond->Object
);
_Objects_Put( &the_cond->Object );
_POSIX_Condition_variables_Free( the_cond );
_Objects_Allocator_unlock();
return 0;
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE:
#endif
case OBJECTS_ERROR:
break;
}
_Objects_Allocator_unlock();
return EINVAL;
}
/**
* This directive allows a thread to delete a rwlock specified by
* the rwlock id. The rwlock is freed back to the inactive
* rwlock chain.
*
* @param[in] rwlock is the rwlock id
*
* @return This method returns 0 if there was not an
* error. Otherwise, a status code is returned indicating the
* source of the error.
*/
int pthread_rwlock_destroy(
pthread_rwlock_t *rwlock
)
{
POSIX_RWLock_Control *the_rwlock = NULL;
Objects_Locations location;
if ( !rwlock )
return EINVAL;
the_rwlock = _POSIX_RWLock_Get( rwlock, &location );
switch ( location ) {
case OBJECTS_LOCAL:
/*
* If there is at least one thread waiting, then do not delete it.
*/
if ( _Thread_queue_First( &the_rwlock->RWLock.Wait_queue ) != NULL ) {
_Objects_Put( &the_rwlock->Object );
return EBUSY;
}
/*
* POSIX doesn't require behavior when it is locked.
*/
_Objects_Close( &_POSIX_RWLock_Information, &the_rwlock->Object );
_POSIX_RWLock_Free( the_rwlock );
_Objects_Put( &the_rwlock->Object );
return 0;
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE:
#endif
case OBJECTS_ERROR:
break;
}
return EINVAL;
}
ER ref_mbx(
T_RMBX *pk_rmbx,
ID mbxid
)
{
register ITRON_Mailbox_Control *the_mailbox;
Objects_Locations location;
Chain_Control *pending;
if ( !pk_rmbx )
return E_PAR;
the_mailbox = _ITRON_Mailbox_Get( mbxid, &location );
switch ( location ) {
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE:
#endif
case OBJECTS_ERROR:
return _ITRON_Mailbox_Clarify_get_id_error( mbxid );
case OBJECTS_LOCAL:
pending = &the_mailbox->message_queue.Pending_messages;
if ( _Chain_Is_empty( pending ) )
pk_rmbx->pk_msg = NULL;
else
pk_rmbx->pk_msg = (T_MSG *) pending->first;
/*
* Fill in whether or not there is a waiting task
*/
if ( !_Thread_queue_First( &the_mailbox->message_queue.Wait_queue ) )
pk_rmbx->wtsk = FALSE;
else
pk_rmbx->wtsk = TRUE;
break;
}
_ITRON_return_errorno( E_OK );
}
void _CORE_RWLock_Obtain_for_reading(
CORE_RWLock_Control *the_rwlock,
Thread_Control *executing,
Objects_Id id,
bool wait,
Watchdog_Interval timeout,
CORE_RWLock_API_mp_support_callout api_rwlock_mp_support
)
{
ISR_Level level;
/*
* If unlocked, then OK to read.
* If locked for reading and no waiters, then OK to read.
* If any thread is waiting, then we wait.
*/
_ISR_Disable( level );
switch ( the_rwlock->current_state ) {
case CORE_RWLOCK_UNLOCKED:
the_rwlock->current_state = CORE_RWLOCK_LOCKED_FOR_READING;
the_rwlock->number_of_readers += 1;
_ISR_Enable( level );
executing->Wait.return_code = CORE_RWLOCK_SUCCESSFUL;
return;
case CORE_RWLOCK_LOCKED_FOR_READING: {
Thread_Control *waiter;
waiter = _Thread_queue_First( &the_rwlock->Wait_queue );
if ( !waiter ) {
the_rwlock->number_of_readers += 1;
_ISR_Enable( level );
executing->Wait.return_code = CORE_RWLOCK_SUCCESSFUL;
return;
}
break;
}
case CORE_RWLOCK_LOCKED_FOR_WRITING:
break;
}
/*
* If the thread is not willing to wait, then return immediately.
*/
if ( !wait ) {
_ISR_Enable( level );
executing->Wait.return_code = CORE_RWLOCK_UNAVAILABLE;
return;
}
/*
* We need to wait to enter this critical section
*/
_Thread_queue_Enter_critical_section( &the_rwlock->Wait_queue );
executing->Wait.queue = &the_rwlock->Wait_queue;
executing->Wait.id = id;
executing->Wait.option = CORE_RWLOCK_THREAD_WAITING_FOR_READ;
executing->Wait.return_code = CORE_RWLOCK_SUCCESSFUL;
_ISR_Enable( level );
_Thread_queue_Enqueue(
&the_rwlock->Wait_queue,
executing,
STATES_WAITING_FOR_RWLOCK,
timeout
);
/* return to API level so it can dispatch and we block */
}
CORE_RWLock_Status _CORE_RWLock_Release(
CORE_RWLock_Control *the_rwlock,
Thread_Control *executing
)
{
ISR_Level level;
Thread_Control *next;
/*
* If unlocked, then OK to read.
* Otherwise, we have to block.
* If locked for reading and no waiters, then OK to read.
* If any thread is waiting, then we wait.
*/
_ISR_Disable( level );
if ( the_rwlock->current_state == CORE_RWLOCK_UNLOCKED){
_ISR_Enable( level );
executing->Wait.return_code = CORE_RWLOCK_UNAVAILABLE;
return CORE_RWLOCK_SUCCESSFUL;
}
if ( the_rwlock->current_state == CORE_RWLOCK_LOCKED_FOR_READING ) {
the_rwlock->number_of_readers -= 1;
if ( the_rwlock->number_of_readers != 0 ) {
/* must be unlocked again */
_ISR_Enable( level );
return CORE_RWLOCK_SUCCESSFUL;
}
}
/* CORE_RWLOCK_LOCKED_FOR_WRITING or READING with readers */
executing->Wait.return_code = CORE_RWLOCK_SUCCESSFUL;
/*
* Implicitly transition to "unlocked" and find another thread interested
* in obtaining this rwlock.
*/
the_rwlock->current_state = CORE_RWLOCK_UNLOCKED;
_ISR_Enable( level );
next = _Thread_queue_Dequeue( &the_rwlock->Wait_queue );
if ( next ) {
if ( next->Wait.option == CORE_RWLOCK_THREAD_WAITING_FOR_WRITE ) {
the_rwlock->current_state = CORE_RWLOCK_LOCKED_FOR_WRITING;
return CORE_RWLOCK_SUCCESSFUL;
}
/*
* Must be CORE_RWLOCK_THREAD_WAITING_FOR_READING
*/
the_rwlock->number_of_readers += 1;
the_rwlock->current_state = CORE_RWLOCK_LOCKED_FOR_READING;
/*
* Now see if more readers can be let go.
*/
while ( 1 ) {
next = _Thread_queue_First( &the_rwlock->Wait_queue );
if ( !next ||
next->Wait.option == CORE_RWLOCK_THREAD_WAITING_FOR_WRITE )
return CORE_RWLOCK_SUCCESSFUL;
the_rwlock->number_of_readers += 1;
_Thread_queue_Extract( &the_rwlock->Wait_queue, next );
}
}
/* indentation is to match _ISR_Disable at top */
return CORE_RWLOCK_SUCCESSFUL;
}
