anchao commented on code in PR #7088: URL: https://github.com/apache/incubator-nuttx/pull/7088#discussion_r1000108292
########## sched/mqueue/msgsnd.c: ########## @@ -0,0 +1,246 @@ +/**************************************************************************** + * sched/mqueue/msgsnd.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 <assert.h> + +#include <nuttx/cancelpt.h> + +#include "sched/sched.h" +#include "mqueue/msg.h" + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: msgsnd_wait + ****************************************************************************/ + +static int msgsnd_wait(FAR struct msgq_s *msgq, int msgflg) +{ + FAR struct tcb_s *rtcb; + +#ifdef CONFIG_CANCELLATION_POINTS + /* msgsnd_wait() is not a cancellation point, but may be called via + * msgsnd() 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 + + /* Verify that the queue is indeed full as the caller thinks + * Loop until there are fewer than max allowable messages in the + * receiving message queue + */ + + while (msgq->nmsgs >= msgq->maxmsgs) + { + /* Should we block until there is sufficient space in the + * message queue? + */ + + if ((msgflg & IPC_NOWAIT) != 0) + { + return -EAGAIN; + } + + /* Block until the message queue is no longer full. + * When we are unblocked, we will try again + */ + + rtcb = this_task(); + rtcb->waitobj = msgq; + msgq->cmn.nwaitnotfull++; + + /* Initialize the errcode used to communication wake-up error + * conditions. + */ + + rtcb->errcode = 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). + */ + + if (rtcb->errcode != OK) + { + return -rtcb->errcode; + } + } + + return OK; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: msgsnd + * + * Description: + * The msgsnd() function is used to send a message to the queue + * associated with the message queue identifier specified by msqid. + * The msgp argument points to a user-defined buffer that must contain + * first a field of type long int that will specify the type of the + * message, and then a data portion that will hold the data bytes of + * the message. + * + * Input Parameters: + * msqid - Message queue identifier + * msgp - Pointer to a buffer with the message to be sent + * msgsz - Length of the data part of the message to be sent + * msgflg - Operations flags + * + * 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 full 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 msgsnd(int msqid, FAR const void *msgp, size_t msgsz, int msgflg) +{ + FAR const struct mymsg *buf = msgp; + FAR struct msgbuf_s *msg; + FAR struct msgq_s *msgq; + FAR struct tcb_s *btcb; + irqstate_t flags; + int ret = OK; + + if (msgp == NULL) + { + ret = -EFAULT; + goto errout; + } + + flags = enter_critical_section(); + + msgq = nxmsg_lookup(msqid); + if (msgq == NULL) + { + ret = -EINVAL; + goto errout_with_critical; + } + + if (msgsz > msgq->maxmsgsize) + { + ret = -EMSGSIZE; + goto errout_with_critical; + } + + if (!up_interrupt_context()) /* In an interrupt handler? */ + { + /* No.. Not in an interrupt handler. Is the message queue FULL? */ + + if (msgq->nmsgs >= msgq->maxmsgs) + { + /* Yes.. the message queue is full. Wait for space to become + * available in the message queue. + */ + + ret = msgsnd_wait(msgq, msgflg); + } Review Comment: Done -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
