path: root/cpukit/posix/src/mqueuenotify.c

/* SPDX-License-Identifier: BSD-2-Clause */

/**
 * @file
 *
 * @ingroup POSIX_MQUEUE
 *
 * @brief Notify Process that a Message is Available on a Queue
 */

/*
 *  COPYRIGHT (c) 1989-2007.
 *  On-Line Applications Research Corporation (OAR).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <rtems/posix/mqueueimpl.h>

#include <signal.h>

static void _POSIX_Message_queue_Notify_handler(
  CORE_message_queue_Control *the_message_queue,
  Thread_queue_Context       *queue_context
)
{
  POSIX_Message_queue_Control *the_mq;
  int                          signo;

  the_mq = RTEMS_CONTAINER_OF(
    the_message_queue,
    POSIX_Message_queue_Control,
    Message_queue
  );

  signo = the_mq->notification.sigev_signo;
  _CORE_message_queue_Set_notify( &the_mq->Message_queue, NULL );
  _CORE_message_queue_Release( &the_mq->Message_queue, queue_context );

  kill( getpid(), signo );
}

int mq_notify(
  mqd_t                  mqdes,
  const struct sigevent *notification
)
{
  POSIX_Message_queue_Control *the_mq;
  Thread_queue_Context         queue_context;

  the_mq = _POSIX_Message_queue_Get( mqdes, &queue_context );

  if ( the_mq == NULL ) {
    rtems_set_errno_and_return_minus_one( EBADF );
  }

  _CORE_message_queue_Acquire_critical(
    &the_mq->Message_queue,
    &queue_context
  );

  if ( the_mq->open_count == 0 ) {
    _CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
    rtems_set_errno_and_return_minus_one( EBADF );
  }

  if ( notification != NULL ) {
    if ( _CORE_message_queue_Is_notify_enabled( &the_mq->Message_queue ) ) {
      _CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
      rtems_set_errno_and_return_minus_one( EBUSY );
    }

    the_mq->notification = *notification;

    _CORE_message_queue_Set_notify(
      &the_mq->Message_queue,
      _POSIX_Message_queue_Notify_handler
    );
  } else {
    _CORE_message_queue_Set_notify( &the_mq->Message_queue, NULL );
  }

  _CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
  return 0;
}