202 lines
7.0 KiB
C
202 lines
7.0 KiB
C
/****************************************************************************
|
|
* sched/mqueue/mq_receive.c
|
|
*
|
|
* Copyright (C) 2007, 2009, 2016-2017 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 <stdbool.h>
|
|
#include <errno.h>
|
|
#include <mqueue.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/irq.h>
|
|
#include <nuttx/arch.h>
|
|
#include <nuttx/mqueue.h>
|
|
#include <nuttx/cancelpt.h>
|
|
|
|
#include "mqueue/mqueue.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: nxmq_receive
|
|
*
|
|
* Description:
|
|
* This function receives the oldest of the highest priority messages
|
|
* from the message queue specified by "mqdes." This is an internal OS
|
|
* interface. It is functionally equivalent to mq_receive except that:
|
|
*
|
|
* - It is not a cancellaction point, and
|
|
* - It does not modify the errno value.
|
|
*
|
|
* See comments with mq_receive() for a more complete description of the
|
|
* behavior of this function
|
|
*
|
|
* Input Parameters:
|
|
* mqdes - Message Queue Descriptor
|
|
* msg - Buffer to receive the message
|
|
* msglen - Size of the buffer in bytes
|
|
* prio - If not NULL, the location to store message priority.
|
|
*
|
|
* Returned Value:
|
|
* This is an internal OS interface and should not be used by applications.
|
|
* It follows the NuttX internal error return policy: Zero (OK) is
|
|
* returned on success. A negated errno value is returned on failure.
|
|
* (see mq_receive() for the list list valid return values).
|
|
*
|
|
****************************************************************************/
|
|
|
|
ssize_t nxmq_receive(mqd_t mqdes, FAR char *msg, size_t msglen,
|
|
FAR int *prio)
|
|
{
|
|
FAR struct mqueue_msg_s *mqmsg;
|
|
irqstate_t flags;
|
|
ssize_t ret;
|
|
|
|
DEBUGASSERT(up_interrupt_context() == false);
|
|
|
|
/* Verify the input parameters and, in case of an error, set
|
|
* errno appropriately.
|
|
*/
|
|
|
|
ret = nxmq_verify_receive(mqdes, msg, msglen);
|
|
if (ret < 0)
|
|
{
|
|
return ret;
|
|
}
|
|
|
|
/* Get the next message from the message queue. We will disable
|
|
* pre-emption until we have completed the message received. This
|
|
* is not too bad because if the receipt takes a long time, it will
|
|
* be because we are blocked waiting for a message and pre-emption
|
|
* will be re-enabled while we are blocked
|
|
*/
|
|
|
|
sched_lock();
|
|
|
|
/* Furthermore, nxmq_wait_receive() expects to have interrupts disabled
|
|
* because messages can be sent from interrupt level.
|
|
*/
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Get the message from the message queue */
|
|
|
|
ret = nxmq_wait_receive(mqdes, &mqmsg);
|
|
leave_critical_section(flags);
|
|
|
|
/* Check if we got a message from the message queue. We might
|
|
* not have a message if:
|
|
*
|
|
* - The message queue is empty and O_NONBLOCK is set in the mqdes
|
|
* - The wait was interrupted by a signal
|
|
*/
|
|
|
|
if (ret >= 0)
|
|
{
|
|
DEBUGASSERT(mqmsg != NULL);
|
|
ret = nxmq_do_receive(mqdes, mqmsg, msg, prio);
|
|
}
|
|
|
|
sched_unlock();
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: mq_receive
|
|
*
|
|
* Description:
|
|
* This function receives the oldest of the highest priority messages
|
|
* from the message queue specified by "mqdes." If the size of the
|
|
* buffer in bytes (msglen) is less than the "mq_msgsize" attribute of
|
|
* the message queue, mq_receive will return an error. Otherwise, the
|
|
* selected message is removed from the queue and copied to "msg."
|
|
*
|
|
* If the message queue is empty and O_NONBLOCK was not set,
|
|
* mq_receive() will block until a message is added to the message
|
|
* queue. If more than one task is waiting to receive a message, only
|
|
* the task with the highest priority that has waited the longest will
|
|
* be unblocked.
|
|
*
|
|
* If the queue is empty and O_NONBLOCK is set, ERROR will be returned.
|
|
*
|
|
* Input Parameters:
|
|
* mqdes - Message Queue Descriptor
|
|
* msg - Buffer to receive the message
|
|
* msglen - Size of the buffer in bytes
|
|
* prio - If not NULL, the location to store message priority.
|
|
*
|
|
* Returned Value:
|
|
* One success, the length of the selected message in bytes is returned.
|
|
* On failure, -1 (ERROR) is returned and the errno is set appropriately:
|
|
*
|
|
* EAGAIN The queue was empty, and the O_NONBLOCK flag was set
|
|
* for the message queue description referred to by 'mqdes'.
|
|
* EPERM Message queue opened not opened for reading.
|
|
* EMSGSIZE 'msglen' was less than the maxmsgsize attribute of the
|
|
* message queue.
|
|
* EINTR The call was interrupted by a signal handler.
|
|
* EINVAL Invalid 'msg' or 'mqdes'
|
|
*
|
|
****************************************************************************/
|
|
|
|
ssize_t mq_receive(mqd_t mqdes, FAR char *msg, size_t msglen,
|
|
FAR int *prio)
|
|
{
|
|
int ret;
|
|
|
|
/* mq_receive() is a cancellation point */
|
|
|
|
(void)enter_cancellation_point();
|
|
|
|
/* Let nxmq_receive do all of the work */
|
|
|
|
ret = nxmq_receive(mqdes, msg, msglen, prio);
|
|
if (ret < 0)
|
|
{
|
|
set_errno(-ret);
|
|
ret = ERROR;
|
|
}
|
|
|
|
leave_cancellation_point();
|
|
return ret;
|
|
}
|