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/**
* @file
*
* @brief POSIX Condition Variables Wait Support
* @ingroup POSIX_COND_VARS
*/
/*
* COPYRIGHT (c) 1989-2014.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <pthread.h>
#include <errno.h>
#include <rtems/system.h>
#include <rtems/score/watchdog.h>
#include <rtems/score/statesimpl.h>
#include <rtems/posix/condimpl.h>
#include <rtems/posix/time.h>
#include <rtems/posix/muteximpl.h>
int _POSIX_Condition_variables_Wait_support(
pthread_cond_t *cond,
pthread_mutex_t *mutex,
Watchdog_Interval timeout,
bool already_timedout
)
{
POSIX_Condition_variables_Control *the_cond;
POSIX_Mutex_Control *the_mutex;
Objects_Locations location;
int status;
int mutex_status;
Thread_Control *executing;
the_mutex = _POSIX_Mutex_Get( mutex, &location );
if ( !the_mutex ) {
return EINVAL;
}
_Objects_Put_without_thread_dispatch( &the_mutex->Object );
the_cond = _POSIX_Condition_variables_Get( cond, &location );
switch ( location ) {
case OBJECTS_LOCAL:
if ( the_cond->Mutex && ( the_cond->Mutex != *mutex ) ) {
_Objects_Put( &the_cond->Object );
return EINVAL;
}
mutex_status = pthread_mutex_unlock( mutex );
/*
* Historically, we ignored the return code since the behavior
* is undefined by POSIX. But GNU/Linux returns EPERM in this
* case, so we follow their lead.
*/
if ( mutex_status ) {
_Objects_Put( &the_cond->Object );
return EPERM;
}
if ( !already_timedout ) {
the_cond->Mutex = *mutex;
executing = _Thread_Executing;
executing->Wait.return_code = 0;
executing->Wait.id = *cond;
_Thread_queue_Enqueue(
&the_cond->Wait_queue,
executing,
STATES_WAITING_FOR_CONDITION_VARIABLE
| STATES_INTERRUPTIBLE_BY_SIGNAL,
timeout,
ETIMEDOUT
);
_Objects_Put( &the_cond->Object );
/*
* Switch ourself out because we blocked as a result of the
* _Thread_queue_Enqueue.
*/
/*
* If the thread is interrupted, while in the thread queue, by
* a POSIX signal, then pthread_cond_wait returns spuriously,
* according to the POSIX standard. It means that pthread_cond_wait
* returns a success status, except for the fact that it was not
* woken up a pthread_cond_signal or a pthread_cond_broadcast.
*/
status = executing->Wait.return_code;
if ( status == EINTR )
status = 0;
} else {
_Objects_Put( &the_cond->Object );
status = ETIMEDOUT;
}
/*
* When we get here the dispatch disable level is 0.
*/
mutex_status = pthread_mutex_lock( mutex );
if ( mutex_status )
return EINVAL;
return status;
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE:
#endif
case OBJECTS_ERROR:
break;
}
return EINVAL;
}
|
