/**
* @file
*
* @ingroup POSIX_COND_VARS
*
* @brief POSIX Condition Variables Wait Support
*/
/*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/posix/condimpl.h>
#include <rtems/posix/posixapi.h>
#include <rtems/score/assert.h>
#include <rtems/score/statesimpl.h>
#include <rtems/score/status.h>
#include <rtems/score/threaddispatch.h>
static void _POSIX_Condition_variables_Mutex_unlock(
Thread_queue_Queue *queue,
Thread_Control *the_thread,
Thread_queue_Context *queue_context
)
{
POSIX_Condition_variables_Control *the_cond;
int mutex_error;
the_cond = POSIX_CONDITION_VARIABLE_OF_THREAD_QUEUE_QUEUE( queue );
mutex_error = pthread_mutex_unlock( the_cond->mutex );
if ( mutex_error != 0 ) {
/*
* 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.
*/
_Assert( mutex_error == EINVAL || mutex_error == EPERM );
_Thread_Continue( the_thread, STATUS_NOT_OWNER );
}
}
static void _POSIX_Condition_variables_Enqueue_no_timeout(
Thread_queue_Queue *queue,
Thread_Control *the_thread,
Per_CPU_Control *cpu_self,
Thread_queue_Context *queue_context
)
{
_POSIX_Condition_variables_Mutex_unlock( queue, the_thread, queue_context );
}
static void _POSIX_Condition_variables_Enqueue_with_timeout_monotonic(
Thread_queue_Queue *queue,
Thread_Control *the_thread,
Per_CPU_Control *cpu_self,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Add_timeout_monotonic_timespec(
queue,
the_thread,
cpu_self,
queue_context
);
_POSIX_Condition_variables_Mutex_unlock( queue, the_thread, queue_context );
}
static void _POSIX_Condition_variables_Enqueue_with_timeout_realtime(
Thread_queue_Queue *queue,
Thread_Control *the_thread,
Per_CPU_Control *cpu_self,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Add_timeout_realtime_timespec(
queue,
the_thread,
cpu_self,
queue_context
);
_POSIX_Condition_variables_Mutex_unlock( queue, the_thread, queue_context );
}
int _POSIX_Condition_variables_Wait_support(
pthread_cond_t *cond,
pthread_mutex_t *mutex,
const struct timespec *abstime
)
{
POSIX_Condition_variables_Control *the_cond;
unsigned long flags;
Thread_queue_Context queue_context;
int error;
Thread_Control *executing;
the_cond = _POSIX_Condition_variables_Get( cond );
POSIX_CONDITION_VARIABLES_VALIDATE_OBJECT( the_cond, flags );
_Thread_queue_Context_initialize( &queue_context );
if ( abstime != NULL ) {
_Thread_queue_Context_set_timeout_argument( &queue_context, abstime, true );
if ( _POSIX_Condition_variables_Get_clock( flags ) == CLOCK_MONOTONIC ) {
_Thread_queue_Context_set_enqueue_callout(
&queue_context,
_POSIX_Condition_variables_Enqueue_with_timeout_monotonic
);
} else {
_Thread_queue_Context_set_enqueue_callout(
&queue_context,
_POSIX_Condition_variables_Enqueue_with_timeout_realtime
);
}
} else {
_Thread_queue_Context_set_enqueue_callout(
&queue_context,
_POSIX_Condition_variables_Enqueue_no_timeout
);
}
executing = _POSIX_Condition_variables_Acquire( the_cond, &queue_context );
if (
the_cond->mutex != POSIX_CONDITION_VARIABLES_NO_MUTEX
&& the_cond->mutex != mutex
) {
_POSIX_Condition_variables_Release( the_cond, &queue_context );
return EINVAL;
}
the_cond->mutex = mutex;
_Thread_queue_Context_set_thread_state(
&queue_context,
STATES_WAITING_FOR_CONDITION_VARIABLE
);
_Thread_queue_Enqueue(
&the_cond->Queue.Queue,
POSIX_CONDITION_VARIABLES_TQ_OPERATIONS,
executing,
&queue_context
);
error = _POSIX_Get_error_after_wait( executing );
/*
* 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 ( error == EINTR ) {
error = 0;
}
/*
* When we get here the dispatch disable level is 0.
*/
if ( error != EPERM ) {
int mutex_error;
mutex_error = pthread_mutex_lock( mutex );
if ( mutex_error != 0 ) {
_Assert( mutex_error == EINVAL );
error = EINVAL;
}
}
return error;
}