/****************************************************************************
* sched/mq_send.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 <sys/types.h>
#include <mqueue.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include "os_internal.h"
#include "mq_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: mq_send
*
* Description:
* This function adds the specificied message (msg) to the message queue
* (mqdes). The "msglen" parameter specifies the length of the message
* in bytes pointed to by "msg." This length must not exceed the maximum
* message length from the mq_getattr().
*
* If the message queue is not full, mq_send() place the message in the
* message queue at the position indicated by the "prio" argrument.
* Messages with higher priority will be inserted before lower priority
* messages. The value of "prio" must not exceed MQ_PRIO_MAX.
*
* If the specified message queue is full and O_NONBLOCK is not set in the
* message queue, then mq_send() will block until space becomes available
* to the queue the message.
*
* If the message queue is full and O_NONBLOCK is set, the message is not
* queued and ERROR is returned.
*
* Parameters:
* mqdes - Message queue descriptor
* msg - Message to send
* msglen - The length of the message in bytes
* prio - The priority of the message
*
* Return Value:
* On success, mq_send() returns 0 (OK); on error, -1 (ERROR)
* is returned, with errno set to indicate the error:
*
* EAGAIN The queue was empty, and the O_NONBLOCK flag was set for the
* message queue description referred to by mqdes.
* EINVAL Either msg or mqdes is NULL or the value of prio is invalid.
* EPERM Message queue opened not opened for writing.
* EMSGSIZE 'msglen' was greater than the maxmsgsize attribute of the
* message queue.
* EINTR The call was interrupted by a signal handler.
*
* Assumptions/restrictions:
*
****************************************************************************/
int mq_send(mqd_t mqdes, const void *msg, size_t msglen, int prio)
{
FAR msgq_t *msgq;
FAR mqmsg_t *mqmsg = NULL;
irqstate_t saved_state;
int ret = ERROR;
/* Verify the input parameters -- setting errno appropriately
* on any failures to verify.
*/
if (mq_verifysend(mqdes, msg, msglen, prio) != OK)
{
return ERROR;
}
/* Get a pointer to the message queue */
sched_lock();
msgq = mqdes->msgq;
/* Allocate a message structure:
* - Immediately if we are called from an interrupt handler.
* - Immediately if the message queue is not full, or
* - After successfully waiting for the message queue to become
* non-FULL. This would fail with EAGAIN, EINTR, or ETIMEOUT.
*/
saved_state = irqsave();
if (up_interrupt_context() || /* In an interrupt handler */
msgq->nmsgs < msgq->maxmsgs || /* OR Message queue not full */
mq_waitsend(mqdes) == OK) /* OR Successfully waited for mq not full */
{
/* Allocate the message */
irqrestore(saved_state);
mqmsg = mq_msgalloc();
}
else
{
/* We cannot send the message (and didn't even try to allocate it)
* because:
* - We are not in an interrupt handler AND
* - The message queue is full AND
* - When we tried waiting, the wait was unsuccessful.
*/
irqrestore(saved_state);
}
/* Check if we were able to get a message structure -- this can fail
* either because we cannot send the message (and didn't bother trying
* to allocate it) or because the allocation failed.
*/
if (mqmsg)
{
/* Yes, perform the message send. */
ret = mq_dosend(mqdes, mqmsg, msg, msglen, prio);
}
sched_unlock();
return ret;
}
