posix/src/mqueuenotify.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup POSIX_MQUEUE
0007  *
0008  * @brief Notify Process that a Message is Available on a Queue
0009  */
0010
0011 /*
0012  *  COPYRIGHT (c) 1989-2007.
0013  *  On-Line Applications Research Corporation (OAR).
0014  *
0015  * Redistribution and use in source and binary forms, with or without
0016  * modification, are permitted provided that the following conditions
0017  * are met:
0018  * 1. Redistributions of source code must retain the above copyright
0019  *    notice, this list of conditions and the following disclaimer.
0020  * 2. Redistributions in binary form must reproduce the above copyright
0021  *    notice, this list of conditions and the following disclaimer in the
0022  *    documentation and/or other materials provided with the distribution.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #ifdef HAVE_CONFIG_H
0038 #include "config.h"
0039 #endif
0040
0041 #include <rtems/posix/mqueueimpl.h>
0042
0043 #include <signal.h>
0044
0045 static void _POSIX_Message_queue_Notify_handler(
0046   CORE_message_queue_Control *the_message_queue,
0047   Thread_queue_Context       *queue_context
0048 )
0049 {
0050   POSIX_Message_queue_Control *the_mq;
0051   int                          signo;
0052
0053   the_mq = RTEMS_CONTAINER_OF(
0054     the_message_queue,
0055     POSIX_Message_queue_Control,
0056     Message_queue
0057   );
0058
0059   signo = the_mq->notification.sigev_signo;
0060   _CORE_message_queue_Set_notify( &the_mq->Message_queue, NULL );
0061   _CORE_message_queue_Release( &the_mq->Message_queue, queue_context );
0062
0063   kill( getpid(), signo );
0064 }
0065
0066 int mq_notify(
0067   mqd_t                  mqdes,
0068   const struct sigevent *notification
0069 )
0070 {
0071   POSIX_Message_queue_Control *the_mq;
0072   Thread_queue_Context         queue_context;
0073
0074   the_mq = _POSIX_Message_queue_Get( mqdes, &queue_context );
0075
0076   if ( the_mq == NULL ) {
0077     rtems_set_errno_and_return_minus_one( EBADF );
0078   }
0079
0080   _CORE_message_queue_Acquire_critical(
0081     &the_mq->Message_queue,
0082     &queue_context
0083   );
0084
0085   if ( the_mq->open_count == 0 ) {
0086     _CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
0087     rtems_set_errno_and_return_minus_one( EBADF );
0088   }
0089
0090   if ( notification != NULL ) {
0091     if ( _CORE_message_queue_Is_notify_enabled( &the_mq->Message_queue ) ) {
0092       _CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
0093       rtems_set_errno_and_return_minus_one( EBUSY );
0094     }
0095
0096     the_mq->notification = *notification;
0097
0098     _CORE_message_queue_Set_notify(
0099       &the_mq->Message_queue,
0100       _POSIX_Message_queue_Notify_handler
0101     );
0102   } else {
0103     _CORE_message_queue_Set_notify( &the_mq->Message_queue, NULL );
0104   }
0105
0106   _CORE_message_queue_Release( &the_mq->Message_queue, &queue_context );
0107   return 0;
0108 }