px4-firmware/nuttx/sched/mq_descreate.c

160 lines
5.0 KiB
C

/****************************************************************************
* sched/mq_descreate.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 <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <mqueue.h>
#include <sched.h>
#include <queue.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/kmalloc.h>
#include "os_internal.h"
#include "sig_internal.h"
#include "mq_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mq_desalloc
*
* Description:
* Allocate a message queue descriptor.
*
* Inputs:
* None
*
* Return Value:
* Reference to the allocated mq descriptor.
*
****************************************************************************/
static mqd_t mq_desalloc(void)
{
mqd_t mqdes;
/* Try to get the message descriptorfrom the free list */
mqdes = (mqd_t)sq_remfirst(&g_desfree);
/* Check if we got one. */
if (!mqdes)
{
/* Add another block of message descriptors to the list */
mq_desblockalloc();
/* And try again */
mqdes = (mqd_t)sq_remfirst(&g_desfree);
}
return mqdes;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mq_descreate
*
* Description:
* Create a message queue descriptor for the specified TCB
*
* Inputs:
* TCB - task that needs the descriptor.
* msgq - Named message queue containing the message
* oflags - access rights for the descriptor
*
* Return Value:
* On success, the message queue descriptor is returned. NULL is returned
* on a failure to allocate.
*
****************************************************************************/
mqd_t mq_descreate(FAR _TCB* mtcb, FAR msgq_t* msgq, int oflags)
{
mqd_t mqdes;
/* Create a message queue descriptor for the TCB */
mqdes = mq_desalloc();
if (mqdes)
{
/* Initialize the MQ descriptor */
memset(mqdes, 0, sizeof(struct mq_des));
mqdes->msgq = msgq;
mqdes->oflags = oflags;
/* And add it to the specified tasks's TCB */
sq_addlast((FAR sq_entry_t*)mqdes, &mtcb->msgdesq);
}
return mqdes;
}