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- /****************************************************************************
- * sched/mqueue/mq_timedsend.c
- *
- * Copyright (C) 2007-2009, 2011, 2013-2017 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 <stdint.h>
- #include <stdbool.h>
- #include <unistd.h>
- #include <mqueue.h>
- #include <errno.h>
- #include <debug.h>
- #include <nuttx/irq.h>
- #include <nuttx/arch.h>
- #include <nuttx/wdog.h>
- #include <nuttx/cancelpt.h>
- #include "clock/clock.h"
- #include "sched/sched.h"
- #include "mqueue/mqueue.h"
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: nxmq_sndtimeout
- *
- * Description:
- * This function is called if the timeout elapses before the message queue
- * becomes non-full.
- *
- * Input Parameters:
- * argc - the number of arguments (should be 1)
- * pid - the task ID of the task to wakeup
- *
- * Returned Value:
- * None
- *
- * Assumptions:
- *
- ****************************************************************************/
- static void nxmq_sndtimeout(int argc, wdparm_t pid)
- {
- FAR struct tcb_s *wtcb;
- irqstate_t flags;
- /* Disable interrupts. This is necessary because an interrupt handler may
- * attempt to send a message while we are doing this.
- */
- flags = enter_critical_section();
- /* Get the TCB associated with this pid. It is possible that task may no
- * longer be active when this watchdog goes off.
- */
- wtcb = sched_gettcb((pid_t)pid);
- /* It is also possible that an interrupt/context switch beat us to the
- * punch and already changed the task's state.
- */
- if (wtcb != NULL && wtcb->task_state == TSTATE_WAIT_MQNOTFULL)
- {
- /* Restart with task with a timeout error */
- nxmq_wait_irq(wtcb, ETIMEDOUT);
- }
- /* Interrupts may now be re-enabled. */
- leave_critical_section(flags);
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: nxmq_timedsend
- *
- * Description:
- * This function adds the specified message (msg) to the message queue
- * (mqdes). nxmq_timedsend() behaves just like mq_send(), except
- * that if the queue is full and the O_NONBLOCK flag is not enabled for
- * the message queue description, then abstime points to a structure which
- * specifies a ceiling on the time for which the call will block.
- *
- * nxmq_timedsend() is functionally equivalent to mq_timedsend() except
- * that:
- *
- * - It is not a cancellation point, and
- * - It does not modify the errno value.
- *
- * See comments with mq_timedsend() for a more complete description of the
- * behavior of this function
- *
- * Input Parameters:
- * mqdes - Message queue descriptor
- * msg - Message to send
- * msglen - The length of the message in bytes
- * prio - The priority of the message
- * abstime - the absolute time to wait until a timeout is decleared
- *
- * 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_timedsend() for the list list valid return values).
- *
- * 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.
- *
- ****************************************************************************/
- int nxmq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen,
- unsigned int prio, FAR const struct timespec *abstime)
- {
- FAR struct tcb_s *rtcb = this_task();
- FAR struct mqueue_inode_s *msgq;
- FAR struct mqueue_msg_s *mqmsg = NULL;
- irqstate_t flags;
- sclock_t ticks;
- int result;
- int ret;
- DEBUGASSERT(up_interrupt_context() == false && rtcb->waitdog == NULL);
- /* Verify the input parameters on any failures to verify. */
- ret = nxmq_verify_send(mqdes, msg, msglen, prio);
- if (ret < 0)
- {
- return ret;
- }
- /* Pre-allocate a message structure */
- mqmsg = nxmq_alloc_msg();
- if (mqmsg == NULL)
- {
- /* Failed to allocate the message. nxmq_alloc_msg() does not set the
- * errno value.
- */
- return -ENOMEM;
- }
- /* Get a pointer to the message queue */
- sched_lock();
- msgq = mqdes->msgq;
- /* OpenGroup.org: "Under no circumstance shall the operation fail with a
- * timeout if there is sufficient room in the queue to add the message
- * immediately. The validity of the abstime parameter need not be checked
- * when there is sufficient room in the queue."
- *
- * Also ignore the time value if for some crazy reason we were called from
- * an interrupt handler. This probably really should be an assertion.
- *
- * NOTE: There is a race condition here: What if a message is added by
- * interrupt related logic so that queue again becomes non-empty. That
- * is handled because nxmq_do_send() will permit the maxmsgs limit to be
- * exceeded in that case.
- */
- if (msgq->nmsgs < msgq->maxmsgs || up_interrupt_context())
- {
- /* Do the send with no further checks (possibly exceeding maxmsgs)
- * Currently nxmq_do_send() always returns OK.
- */
- ret = nxmq_do_send(mqdes, mqmsg, msg, msglen, prio);
- sched_unlock();
- return ret;
- }
- /* The message queue is full... We are going to wait. Now we must have a
- * valid time value.
- */
- if (!abstime || abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
- {
- ret = -EINVAL;
- goto errout_with_mqmsg;
- }
- /* Create a watchdog. We will not actually need this watchdog
- * unless the queue is full, but we will reserve it up front
- * before we enter the following critical section.
- */
- rtcb->waitdog = wd_create();
- if (!rtcb->waitdog)
- {
- ret = -EINVAL;
- goto errout_with_mqmsg;
- }
- /* We are not in an interrupt handler and the message queue is full.
- * Set up a timed wait for the message queue to become non-full.
- *
- * Convert the timespec to clock ticks. We must have interrupts
- * disabled here so that this time stays valid until the wait begins.
- */
- flags = enter_critical_section();
- result = clock_abstime2ticks(CLOCK_REALTIME, abstime, &ticks);
- /* If the time has already expired and the message queue is empty,
- * return immediately.
- */
- if (result == OK && ticks <= 0)
- {
- result = ETIMEDOUT;
- }
- /* Handle any time-related errors */
- if (result != OK)
- {
- ret = -result;
- goto errout_in_critical_section;
- }
- /* Start the watchdog and begin the wait for MQ not full */
- (void)wd_start(rtcb->waitdog, ticks, (wdentry_t)nxmq_sndtimeout,
- 1, getpid());
- /* And wait for the message queue to be non-empty */
- ret = nxmq_wait_send(mqdes);
- /* This may return with an error and errno set to either EINTR
- * or ETIMEOUT. Cancel the watchdog timer in any event.
- */
- wd_cancel(rtcb->waitdog);
- /* Check if nxmq_wait_send() failed */
- if (ret < 0)
- {
- /* nxmq_wait_send() failed. */
- goto errout_in_critical_section;
- }
- /* That is the end of the atomic operations */
- leave_critical_section(flags);
- /* If any of the above failed, set the errno. Otherwise, there should
- * be space for another message in the message queue. NOW we can allocate
- * the message structure.
- *
- * Currently nxmq_do_send() always returns OK.
- */
- ret = nxmq_do_send(mqdes, mqmsg, msg, msglen, prio);
- sched_unlock();
- wd_delete(rtcb->waitdog);
- rtcb->waitdog = NULL;
- leave_cancellation_point();
- return ret;
- /* Exit here with (1) the scheduler locked, (2) a message allocated, (3) a
- * wdog allocated, and (4) interrupts disabled.
- */
- errout_in_critical_section:
- leave_critical_section(flags);
- wd_delete(rtcb->waitdog);
- rtcb->waitdog = NULL;
- /* Exit here with (1) the scheduler locked and 2) a message allocated. The
- * error code is in 'result'
- */
- errout_with_mqmsg:
- nxmq_free_msg(mqmsg);
- sched_unlock();
- return ret;
- }
- /****************************************************************************
- * Name: mq_timedsend
- *
- * Description:
- * This function adds the specified 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_timedsend() 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_timedsend() will block until space becomes available
- * to the queue the message or a timeout occurs.
- *
- * mq_timedsend() behaves just like mq_send(), except that if the queue
- * is full and the O_NONBLOCK flag is not enabled for the message queue
- * description, then abstime points to a structure which specifies a
- * ceiling on the time for which the call will block. This ceiling is an
- * absolute timeout in seconds and nanoseconds since the Epoch (midnight
- * on the morning of 1 January 1970).
- *
- * If the message queue is full, and the timeout has already expired by
- * the time of the call, mq_timedsend() returns immediately.
- *
- * Input Parameters:
- * mqdes - Message queue descriptor
- * msg - Message to send
- * msglen - The length of the message in bytes
- * prio - The priority of the message
- * abstime - the absolute time to wait until a timeout is decleared
- *
- * Returned 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_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen,
- unsigned int prio, FAR const struct timespec *abstime)
- {
- int ret;
- /* mq_timedsend() is a cancellation point */
- (void)enter_cancellation_point();
- /* Let nxmq_send() do all of the work */
- ret = nxmq_timedsend(mqdes, msg, msglen, prio, abstime);
- if (ret < 0)
- {
- set_errno(-ret);
- ret = ERROR;
- }
- leave_cancellation_point();
- return ret;
- }
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