/****************************************************************************
* fs/mqueue/mq_close.c
*
* Copyright (C) 2007, 2009, 2013-2014 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 <sched.h>
#include <mqueue.h>
#include <assert.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mqueue.h>
#include "inode/inode.h"
#include "mqueue/mqueue.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mq_close
*
* Description:
* This function is used to indicate that the calling task is finished
* with the specified message queue 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 struct mqueue_inode_s *msgq;
FAR struct inode *inode;
/* Verify the inputs */
if (mqdes)
{
sched_lock();
/* Find the message queue associated with the message descriptor */
msgq = mqdes->msgq;
DEBUGASSERT(msgq && msgq->inode);
/* Close/free the message descriptor */
mq_desclose(mqdes);
/* Get the inode from the message queue structure */
inode = msgq->inode;
DEBUGASSERT(inode->u.i_mqueue == msgq);
/* Decrement the reference count on the inode, possibly freeing it */
mq_inode_release(inode);
sched_unlock();
}
return OK;
}
/****************************************************************************
* Name: mq_close
*
* Description:
* Release a reference count on a message queue inode.
*
* Parameters:
* inode - The message queue inode
*
* Return Value:
* None
*
****************************************************************************/
void mq_inode_release(FAR struct inode *inode)
{
/* Decrement the reference count on the inode */
inode_semtake();
if (inode->i_crefs > 0)
{
inode->i_crefs--;
}
/* If the message queue was previously unlinked and the reference count
* has decremented to zero, then release the message queue and delete
* the inode now.
*/
if (inode->i_crefs <= 0 && (inode->i_flags & FSNODEFLAG_DELETED) != 0)
{
FAR struct mqueue_inode_s *msgq = inode->u.i_mqueue;
DEBUGASSERT(msgq);
/* Free the message queue (and any messages left in it) */
mq_msgqfree(msgq);
inode->u.i_mqueue = NULL;
/* Release and free the inode container */
inode_semgive();
inode_free(inode->i_child);
kmm_free(inode);
return;
}
inode_semgive();
}
