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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.

 *

 *  $Id: mqueuesetattr.c,v 1.2 2001-09-27 11:59:17 chris Exp $

 */

#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/posix/seterr.h>

#include <rtems/posix/mqueue.h>

#include <rtems/posix/time.h>

/*PAGE

 *

 *  15.2.7 Set Message Queue Attributes, P1003.1b-1993, p. 281

 */

int mq_setattr(

  mqd_t                 mqdes,

  const struct mq_attr *mqstat,

  struct mq_attr       *omqstat

)

{

  register POSIX_Message_queue_Control *the_mq;

  CORE_message_queue_Control           *the_core_mq;

  Objects_Locations                     location;

  CORE_message_queue_Attributes        *the_mq_attr;

  if ( !mqstat )

    set_errno_and_return_minus_one( EINVAL );

  the_mq = _POSIX_Message_queue_Get( mqdes, &location );

  switch ( location ) {

    case OBJECTS_ERROR:

      set_errno_and_return_minus_one( EBADF );

    case OBJECTS_REMOTE:

      _Thread_Dispatch();

      return POSIX_MP_NOT_IMPLEMENTED();

      set_errno_and_return_minus_one( EINVAL );

    case OBJECTS_LOCAL:

      the_core_mq = &the_mq->Message_queue;

      /*

       *  Return the old values.

       */

      /* XXX this is the same stuff as is in mq_getattr... and probably */

      /* XXX should be in an inlined private routine */

      if ( omqstat ) {

        omqstat->mq_flags   = the_mq->oflag;

        omqstat->mq_msgsize = the_core_mq->maximum_message_size;

        omqstat->mq_maxmsg  = the_core_mq->maximum_pending_messages;

        omqstat->mq_curmsgs = the_core_mq->number_of_pending_messages;

      }

      /*

       *  If blocking was in effect and is not now, then there

       *  may be threads blocked on this message queue which need

       *  to be unblocked to make the state of the message queue

       *  consistent for future use.

       */

      the_mq_attr = &the_core_mq->Attributes;

      if ( !(the_mq->oflag & O_NONBLOCK) &&         /* were blocking */

           (mqstat->mq_flags & O_NONBLOCK) ) {      /* and now are not */

        _CORE_message_queue_Flush_waiting_threads( the_core_mq );

      }

      the_mq->oflag = mqstat->mq_flags;

      _Thread_Enable_dispatch();

      return 0;

  }

  return POSIX_BOTTOM_REACHED();

}