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/*

 *  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.

 *

 *  mqueuerecvsupp.c,v 1.7 2002/04/26 23:39:01 joel Exp

 */

#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/watchdog.h>

#include <rtems/seterr.h>

#include <rtems/posix/mqueue.h>

#include <rtems/posix/time.h>

/*PAGE

 *

 *  _POSIX_Message_queue_Receive_support

 *

 *  NOTE: XXX Document how size, priority, length, and the buffer go

 *        through the layers.

 */

ssize_t _POSIX_Message_queue_Receive_support(

  mqd_t               mqdes,

  char               *msg_ptr,

  size_t              msg_len,

  unsigned int       *msg_prio,

  Watchdog_Interval   timeout

)

{

  POSIX_Message_queue_Control     *the_mq;

  POSIX_Message_queue_Control_fd  *the_mq_fd;

  Objects_Locations                location;

  unsigned32                       length_out;

  the_mq_fd = _POSIX_Message_queue_Get_fd( mqdes, &location );

  switch ( location ) {

    case OBJECTS_ERROR:

      rtems_set_errno_and_return_minus_one( EBADF );

    case OBJECTS_REMOTE:

      _Thread_Dispatch();

      return POSIX_MP_NOT_IMPLEMENTED();

      rtems_set_errno_and_return_minus_one( EINVAL );

    case OBJECTS_LOCAL:

      if ( (the_mq_fd->oflag & O_ACCMODE) == O_WRONLY ) {

        _Thread_Enable_dispatch();

        rtems_set_errno_and_return_minus_one( EBADF );

      }

      the_mq = the_mq_fd->Queue;

      if ( msg_len < the_mq->Message_queue.maximum_message_size ) {

        _Thread_Enable_dispatch();

        rtems_set_errno_and_return_minus_one( EMSGSIZE );

      }

      /*

       *  Now if something goes wrong, we return a "length" of -1

       *  to indicate an error.

       */

      length_out = -1;

      _CORE_message_queue_Seize(

        &the_mq->Message_queue,

        mqdes,

        msg_ptr,

        &length_out,

        (the_mq_fd->oflag & O_NONBLOCK) ? FALSE : TRUE,

        timeout

      );

      _Thread_Enable_dispatch();

      *msg_prio =

        _POSIX_Message_queue_Priority_from_core(_Thread_Executing->Wait.count);

      if ( !_Thread_Executing->Wait.return_code )

        return length_out;

      rtems_set_errno_and_return_minus_one(

        _POSIX_Message_queue_Translate_core_message_queue_return_code(

          _Thread_Executing->Wait.return_code

        )

      );

  }

  return POSIX_BOTTOM_REACHED();

}