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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 <rtems/posix/condimpl.h>
#include <rtems/posix/muteximpl.h>
#include <rtems/score/assert.h>
#include <rtems/score/statesimpl.h>
#include <rtems/score/threaddispatch.h>
THREAD_QUEUE_OBJECT_ASSERT( POSIX_Condition_variables_Control, Wait_queue );
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;
ISR_lock_Context lock_context;
int status;
int mutex_status;
CORE_mutex_Status core_mutex_status;
Per_CPU_Control *cpu_self;
Thread_Control *executing;
if ( mutex == NULL ) {
return EINVAL;
}
the_cond = _POSIX_Condition_variables_Get( cond, &lock_context );
if ( the_cond == NULL ) {
return EINVAL;
}
_POSIX_Condition_variables_Acquire_critical( the_cond, &lock_context );
if (
the_cond->mutex != POSIX_CONDITION_VARIABLES_NO_MUTEX
&& the_cond->mutex != *mutex
) {
_POSIX_Condition_variables_Release( the_cond, &lock_context );
return EINVAL;
}
the_cond->mutex = *mutex;
cpu_self = _Thread_Dispatch_disable_critical( &lock_context );
executing = _Per_CPU_Get_executing( cpu_self );
/*
* Historically, we ignored the unlock status since the behavior
* is undefined by POSIX. But GNU/Linux returns EPERM in this
* case, so we follow their lead.
*/
the_mutex = _POSIX_Mutex_Get_no_protection( mutex );
if (
the_mutex == NULL
|| !_CORE_mutex_Is_owner( &the_mutex->Mutex, executing )
) {
_POSIX_Condition_variables_Release( the_cond, &lock_context );
_Thread_Dispatch_enable( cpu_self );
return EPERM;
}
if ( !already_timedout ) {
executing->Wait.return_code = 0;
_Thread_queue_Enqueue_critical(
&the_cond->Wait_queue.Queue,
POSIX_CONDITION_VARIABLES_TQ_OPERATIONS,
executing,
STATES_WAITING_FOR_CONDITION_VARIABLE,
timeout,
ETIMEDOUT,
&lock_context
);
} else {
_POSIX_Condition_variables_Release( the_cond, &lock_context );
executing->Wait.return_code = ETIMEDOUT;
}
_ISR_lock_ISR_disable( &lock_context );
core_mutex_status = _CORE_mutex_Surrender(
&the_mutex->Mutex,
NULL,
&lock_context
);
_Assert( core_mutex_status == CORE_MUTEX_STATUS_SUCCESSFUL );
(void) core_mutex_status;
/*
* Switch ourself out because we blocked as a result of the
* _Thread_queue_Enqueue_critical().
*/
_Thread_Dispatch_enable( cpu_self );
status = (int) executing->Wait.return_code;
/*
* 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().
*/
if ( status == EINTR ) {
status = 0;
}
/*
* When we get here the dispatch disable level is 0.
*/
mutex_status = pthread_mutex_lock( mutex );
if ( mutex_status != 0 ) {
return EINVAL;
}
return status;
}
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