shared/shmdr/shmdr-receive.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*  Shm_Receive_packet
0004  *
0005  *  This routine is the shared memory locked queue MPCI driver routine
0006  *  used to obtain a packet containing a message from this node's
0007  *  receive queue.
0008  *
0009  *  Input parameters:
0010  *    packet         - address of a pointer to a packet
0011  *
0012  *  Output parameters:
0013  *    *(rpb->packet) - pointer to packet
0014  *                     NULL if no packet currently available
0015  *
0016  *  COPYRIGHT (c) 1989-1999.
0017  *  On-Line Applications Research Corporation (OAR).
0018  *
0019  * Redistribution and use in source and binary forms, with or without
0020  * modification, are permitted provided that the following conditions
0021  * are met:
0022  * 1. Redistributions of source code must retain the above copyright
0023  *    notice, this list of conditions and the following disclaimer.
0024  * 2. Redistributions in binary form must reproduce the above copyright
0025  *    notice, this list of conditions and the following disclaimer in the
0026  *    documentation and/or other materials provided with the distribution.
0027  *
0028  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0029  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0030  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0031  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0032  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0033  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0034  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0035  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0036  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0037  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0038  * POSSIBILITY OF SUCH DAMAGE.
0039  */
0040
0041 #include <rtems.h>
0042 #include "shm_driver.h"
0043
0044 rtems_mpci_entry Shm_Receive_packet(
0045   rtems_packet_prefix **packet
0046 )
0047 {
0048   Shm_Envelope_control *ecb;
0049
0050   ecb = Shm_Locked_queue_Get( Shm_Local_receive_queue );
0051   if ( ecb ) {
0052     *(packet) = Shm_Envelope_control_to_packet_prefix_pointer( ecb );
0053     if ( ecb->Preamble.endian != Shm_Configuration->format )
0054       Shm_Convert_packet( *packet );
0055     Shm_Receive_message_count++;
0056   } else {
0057     *(packet) = NULL;
0058     Shm_Null_message_count++;
0059   }
0060 }