/**************************************************************************** * sched/mqueue/mq_sndinternal.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "sched/sched.h" #include "mqueue/mqueue.h" /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: nxmq_verify_send * * Description: * This is internal, common logic shared by both [nx]mq_send and * [nx]mq_timesend. This function verifies the input parameters that are * common to both functions. * * Input Parameters: * mqdes - Message queue descriptor * msg - Message to send * msglen - The length of the message in bytes * prio - The priority of the message * * Returned Value: * One success, 0 (OK) is returned. On failure, a negated errno value is * returned. * * 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. * ****************************************************************************/ int nxmq_verify_send(mqd_t mqdes, FAR const char *msg, size_t msglen, unsigned int prio) { /* Verify the input parameters */ if (msg == NULL || mqdes == NULL || prio > MQ_PRIO_MAX) { return -EINVAL; } if ((mqdes->oflags & O_WROK) == 0) { return -EPERM; } if (msglen > (size_t)mqdes->msgq->maxmsgsize) { return -EMSGSIZE; } return OK; } /**************************************************************************** * Name: nxmq_alloc_msg * * Description: * The nxmq_alloc_msg function will get a free message for use by the * operating system. The message will be allocated from the g_msgfree * list. * * If the list is empty AND the message is NOT being allocated from the * interrupt level, then the message will be allocated. If a message * cannot be obtained, the operating system is dead and therefore cannot * continue. * * If the list is empty AND the message IS being allocated from the * interrupt level. This function will attempt to get a message from * the g_msgfreeirq list. If this is unsuccessful, the calling interrupt * handler will be notified. * * Input Parameters: * None * * Returned Value: * A reference to the allocated msg structure. On a failure to allocate, * this function PANICs. * ****************************************************************************/ FAR struct mqueue_msg_s *nxmq_alloc_msg(void) { FAR struct mqueue_msg_s *mqmsg; irqstate_t flags; /* If we were called from an interrupt handler, then try to get the message * from generally available list of messages. If this fails, then try the * list of messages reserved for interrupt handlers */ if (up_interrupt_context()) { /* Try the general free list */ mqmsg = (FAR struct mqueue_msg_s *)sq_remfirst(&g_msgfree); if (mqmsg == NULL) { /* Try the free list reserved for interrupt handlers */ mqmsg = (FAR struct mqueue_msg_s *)sq_remfirst(&g_msgfreeirq); } } /* We were not called from an interrupt handler. */ else { /* Try to get the message from the generally available free list. * Disable interrupts -- we might be called from an interrupt handler. */ flags = enter_critical_section(); mqmsg = (FAR struct mqueue_msg_s *)sq_remfirst(&g_msgfree); leave_critical_section(flags); /* If we cannot a message from the free list, then we will have to * allocate one. */ if (mqmsg == NULL) { mqmsg = (FAR struct mqueue_msg_s *) kmm_malloc((sizeof (struct mqueue_msg_s))); /* Check if we allocated the message */ if (mqmsg != NULL) { /* Yes... remember that this message was dynamically * allocated. */ mqmsg->type = MQ_ALLOC_DYN; } } } return mqmsg; } /**************************************************************************** * Name: nxmq_wait_send * * Description: * This is internal, common logic shared by both [nx]mq_send and * [nx]mq_timesend. This function waits until the message queue is not * full. * * Input Parameters: * mqdes - Message queue descriptor * * Returned Value: * On success, nxmq_wait_send() returns 0 (OK); a negated errno value is * returned on any failure: * * EAGAIN The queue was full and the O_NONBLOCK flag was set for the * message queue description referred to by mqdes. * EINTR The call was interrupted by a signal handler. * ETIMEOUT A timeout expired before the message queue became non-full * (mq_timedsend only). * * Assumptions/restrictions: * - The caller has verified the input parameters using nxmq_verify_send(). * - Executes within a critical section established by the caller. * ****************************************************************************/ int nxmq_wait_send(mqd_t mqdes) { FAR struct tcb_s *rtcb; FAR struct mqueue_inode_s *msgq; int ret; #ifdef CONFIG_CANCELLATION_POINTS /* nxmq_wait_send() is not a cancellation point, but may be called via * mq_send() or mq_timedsend() which are cancellation points. */ if (check_cancellation_point()) { /* If there is a pending cancellation, then do not perform * the wait. Exit now with ECANCELED. */ return -ECANCELED; } #endif /* Get a pointer to the message queue */ msgq = mqdes->msgq; /* Verify that the queue is indeed full as the caller thinks */ if (msgq->nmsgs >= msgq->maxmsgs) { /* Should we block until there is sufficient space in the * message queue? */ if ((mqdes->oflags & O_NONBLOCK) != 0) { /* No... We will return an error to the caller. */ return -EAGAIN; } /* Yes... We will not return control until the message queue is * available or we receive a signal or at timeout occurs. */ else { /* Loop until there are fewer than max allowable messages in the * receiving message queue */ while (msgq->nmsgs >= msgq->maxmsgs) { int saved_errno; /* Block until the message queue is no longer full. * When we are unblocked, we will try again */ rtcb = this_task(); rtcb->msgwaitq = msgq; msgq->nwaitnotfull++; /* "Borrow" the per-task errno to communication wake-up error * conditions. */ saved_errno = rtcb->pterrno; rtcb->pterrno = OK; /* Make sure this is not the idle task, descheduling that * isn't going to end well. */ DEBUGASSERT(NULL != rtcb->flink); up_block_task(rtcb, TSTATE_WAIT_MQNOTFULL); /* When we resume at this point, either (1) the message queue * is no longer empty, or (2) the wait has been interrupted by * a signal. We can detect the latter case be examining the * per-task errno value (should be EINTR or ETIMEOUT). */ ret = rtcb->pterrno; rtcb->pterrno = saved_errno; if (ret != OK) { return -ret; } } } } return OK; } /**************************************************************************** * Name: nxmq_do_send * * Description: * This is internal, common logic shared by both [nx]mq_send and * [nx]mq_timesend. This function adds the specified message (msg) to the * message queue (mqdes). Then it notifies any tasks that were waiting * for message queue notifications setup by mq_notify. And, finally, it * awakens any tasks that were waiting for the message not empty event. * * Input Parameters: * mqdes - Message queue descriptor * msg - Message to send * msglen - The length of the message in bytes * prio - The priority of the message * * Returned Value: * This function always returns OK. * ****************************************************************************/ int nxmq_do_send(mqd_t mqdes, FAR struct mqueue_msg_s *mqmsg, FAR const char *msg, size_t msglen, unsigned int prio) { FAR struct tcb_s *btcb; FAR struct mqueue_inode_s *msgq; FAR struct mqueue_msg_s *next; FAR struct mqueue_msg_s *prev; irqstate_t flags; /* Get a pointer to the message queue */ sched_lock(); msgq = mqdes->msgq; /* Construct the message header info */ mqmsg->priority = prio; mqmsg->msglen = msglen; /* Copy the message data into the message */ memcpy((FAR void *)mqmsg->mail, (FAR const void *)msg, msglen); /* Insert the new message in the message queue */ flags = enter_critical_section(); /* Search the message list to find the location to insert the new * message. Each is list is maintained in ascending priority order. */ for (prev = NULL, next = (FAR struct mqueue_msg_s *)msgq->msglist.head; next && prio <= next->priority; prev = next, next = next->next); /* Add the message at the right place */ if (prev) { sq_addafter((FAR sq_entry_t *)prev, (FAR sq_entry_t *)mqmsg, &msgq->msglist); } else { sq_addfirst((FAR sq_entry_t *)mqmsg, &msgq->msglist); } /* Increment the count of messages in the queue */ msgq->nmsgs++; leave_critical_section(flags); /* Check if we need to notify any tasks that are attached to the * message queue */ if (msgq->ntmqdes) { struct sigevent event; pid_t pid; /* Remove the message notification data from the message queue. */ memcpy(&event, &msgq->ntevent, sizeof(struct sigevent)); pid = msgq->ntpid; /* Detach the notification */ memset(&msgq->ntevent, 0, sizeof(struct sigevent)); msgq->ntpid = INVALID_PROCESS_ID; msgq->ntmqdes = NULL; /* Notification the client */ DEBUGVERIFY(nxsig_notification(pid, &event, SI_MESGQ, &msgq->ntwork)); } /* Check if any tasks are waiting for the MQ not empty event. */ flags = enter_critical_section(); if (msgq->nwaitnotempty > 0) { /* Find the highest priority task that is waiting for * this queue to be non-empty in g_waitingformqnotempty * list. sched_lock() should give us sufficient protection since * interrupts should never cause a change in this list */ for (btcb = (FAR struct tcb_s *)g_waitingformqnotempty.head; btcb && btcb->msgwaitq != msgq; btcb = btcb->flink) { } /* If one was found, unblock it */ DEBUGASSERT(btcb); btcb->msgwaitq = NULL; msgq->nwaitnotempty--; up_unblock_task(btcb); } leave_critical_section(flags); sched_unlock(); return OK; }