px4-firmware/nuttx/sched/mq_close.c

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/****************************************************************************
* sched/mq_close.c
*
* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <mqueue.h>
#include <sched.h>
#include "os_internal.h"
#include "mq_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mq_desfree
*
* Description:
* Deallocate a message queue descriptor but returning it to the free list
*
* Inputs:
* mqdes - message queue descriptor to free
*
****************************************************************************/
#define mq_desfree(mqdes) sq_addlast((FAR sq_entry_t*)mqdes, &g_desfree)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mq_close
*
* Description:
* This function is used to indicate that the calling task is finished
* with the specified message queued mqdes. The mq_close() deallocates
* any system resources allocated by the system for use by this task for
* its message queue.
*
* If the calling task has attached a notification to the message queue
* via this mqdes, this attachment will be removed and the message queue
* is available for another process to attach a notification.
*
* Parameters:
* mqdes - Message queue descriptor.
*
* Return Value:
* 0 (OK) if the message queue is closed successfully,
* otherwise, -1 (ERROR).
*
* Assumptions:
* - The behavior of a task that is blocked on either a mq_send() or
* mq_receive() is undefined when mq_close() is called.
* - The results of using this message queue descriptor after a successful
* return from mq_close() is undefined.
*
****************************************************************************/
int mq_close(mqd_t mqdes)
{
FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head;
FAR msgq_t *msgq;
irqstate_t saved_state;
int ret = ERROR;
/* Verify the inputs */
if (mqdes)
{
sched_lock();
/* Remove the message descriptor from the current task's
* list of message descriptors.
*/
sq_rem((FAR sq_entry_t*)mqdes, &rtcb->msgdesq);
/* Find the message queue associated with the message descriptor */
msgq = mqdes->msgq;
/* Check if the calling task has a notification attached to
* the message queue via this mqdes.
*/
#ifndef CONFIG_DISABLE_SIGNALS
if (msgq->ntmqdes == mqdes)
{
msgq->ntpid = INVALID_PROCESS_ID;
msgq->ntsigno = 0;
msgq->ntvalue.sival_int = 0;
msgq->ntmqdes = NULL;
}
#endif
/* Decrement the connection count on the message queue. */
if (msgq->nconnect)
{
msgq->nconnect--;
}
/* If it is no longer connected to any message descriptor and if the
* message queue has already been unlinked, then we can discard the
* message queue.
*/
if (!msgq->nconnect && msgq->unlinked)
{
/* Remove the message queue from the list of all
* message queues
*/
saved_state = irqsave();
(void)sq_rem((FAR sq_entry_t*)msgq, &g_msgqueues);
irqrestore(saved_state);
/* Then deallocate it (and any messages left in it) */
mq_msgqfree(msgq);
}
/* Deallocate the message descriptor */
mq_desfree(mqdes);
sched_unlock();
ret = OK;
}
return ret;
}