/**************************************************************************** * sched/mqueue/mq_timedsend.c * * Copyright (C) 2007-2009, 2011, 2013-2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include #include #include "clock/clock.h" #include "sched/sched.h" #include "mqueue/mqueue.h" /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: mq_sndtimeout * * Description: * This function is called if the timeout elapses before the message queue * becomes non-full. * * Parameters: * argc - the number of arguments (should be 1) * pid - the task ID of the task to wakeup * * Return Value: * None * * Assumptions: * ****************************************************************************/ static void mq_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 && wtcb->task_state == TSTATE_WAIT_MQNOTFULL) { /* Restart with task with a timeout error */ mq_waitirq(wtcb, ETIMEDOUT); } /* Interrupts may now be re-enabled. */ leave_critical_section(flags); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: 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_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. * * 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 * * 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_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, 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; int ticks; int result; int ret = ERROR; DEBUGASSERT(up_interrupt_context() == false && rtcb->waitdog == NULL); /* Verify the input parameters -- setting errno appropriately * on any failures to verify. */ if (mq_verifysend(mqdes, msg, msglen, prio) != OK) { /* mq_verifysend() will set the errno appropriately */ return ERROR; } /* Pre-allocate a message structure */ mqmsg = mq_msgalloc(); if (mqmsg == NULL) { /* Failed to allocate the message. mq_msgalloc() does not set the * errno value. */ set_errno(ENOMEM); return ERROR; } /* 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 mq_dosend() 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 mq_dosend() always returns OK. */ ret = mq_dosend(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) { result = 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) { result = 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) { goto errout_in_critical_section; } /* Start the watchdog and begin the wait for MQ not full */ wd_start(rtcb->waitdog, ticks, (wdentry_t)mq_sndtimeout, 1, getpid()); /* And wait for the message queue to be non-empty */ ret = mq_waitsend(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 mq_waitsend() failed */ if (ret < 0) { /* mq_waitsend() will set the errno, but the error exit will reset it */ result = get_errno(); 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 mq_dosend() always returns OK. */ ret = mq_dosend(mqdes, mqmsg, msg, msglen, prio); sched_unlock(); wd_delete(rtcb->waitdog); rtcb->waitdog = NULL; return ret; /* Exit here with (1) the scheduler locked, (2) a message allocated, (3) a * wdog allocated, and (4) interrupts disabled. The error code is in * 'result' */ 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: mq_msgfree(mqmsg); sched_unlock(); set_errno(result); return ERROR; }