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/**
* @file
*
* @brief Receive Message from Message Queue
* @ingroup POSIXAPI
*/
/*
* NOTE: The structure of the routines is identical to that of POSIX
* Message_queues to leave the option of having unnamed message
* queues at a future date. They are currently not part of the
* POSIX standard but unnamed message_queues are. This is also
* the reason for the apparently unnecessary tracking of
* the process_shared attribute. [In addition to the fact that
* it would be trivial to add pshared to the mq_attr structure
* and have process private message queues.]
*
* This code ignores the O_RDONLY/O_WRONLY/O_RDWR flag at open
* time.
*/
/*
* COPYRIGHT (c) 1989-2008.
* 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 <stdarg.h>
#include <pthread.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <mqueue.h>
#include <rtems/system.h>
#include <rtems/score/todimpl.h>
#include <rtems/seterr.h>
#include <rtems/posix/mqueueimpl.h>
/*
* 15.2.5 Receive a Message From a Message Queue, P1003.1b-1993, p. 279
*
* NOTE: P1003.4b/D8, p. 45 adds mq_timedreceive().
*/
ssize_t mq_timedreceive(
mqd_t mqdes,
char *__restrict msg_ptr,
size_t msg_len,
unsigned int *__restrict msg_prio,
const struct timespec *__restrict abstime
)
{
Watchdog_Interval ticks;
bool do_wait = true;
TOD_Absolute_timeout_conversion_results status;
/*
* POSIX requires that blocking calls with timeouts that take
* an absolute timeout must ignore issues with the absolute
* time provided if the operation would otherwise succeed.
* So we check the abstime provided, and hold on to whether it
* is valid or not. If it isn't correct and in the future,
* then we do a polling operation and convert the UNSATISFIED
* status into the appropriate error.
*
* If the status is TOD_ABSOLUTE_TIMEOUT_INVALID,
* TOD_ABSOLUTE_TIMEOUT_IS_IN_PAST, or TOD_ABSOLUTE_TIMEOUT_IS_NOW,
* then we should not wait.
*/
status = _TOD_Absolute_timeout_to_ticks( abstime, CLOCK_REALTIME, &ticks );
if ( status != TOD_ABSOLUTE_TIMEOUT_IS_IN_FUTURE )
do_wait = false;
return _POSIX_Message_queue_Receive_support(
mqdes,
msg_ptr,
msg_len,
msg_prio,
do_wait,
ticks
);
}
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