283 lines
7.9 KiB
C
283 lines
7.9 KiB
C
/****************************************************************************
|
|
* 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;
|
|
bool switch_needed;
|
|
|
|
#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);
|
|
|
|
/* Remove the tcb task from the ready-to-run list. */
|
|
|
|
switch_needed = nxsched_remove_readytorun(rtcb, true);
|
|
|
|
/* Add the task to the specified blocked task list */
|
|
|
|
rtcb->task_state = TSTATE_WAIT_MQNOTFULL;
|
|
nxsched_add_prioritized(rtcb, MQ_WNFLIST(msgq->cmn));
|
|
|
|
/* Now, perform the context switch if one is needed */
|
|
|
|
if (switch_needed)
|
|
{
|
|
up_switch_context(this_task(), rtcb);
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
|
|
/* Is the message queue FULL? */
|
|
|
|
if (msgq->nmsgs >= msgq->maxmsgs)
|
|
{
|
|
if (!up_interrupt_context()) /* In an interrupt handler? */
|
|
{
|
|
/* Yes.. the message queue is full. Wait for space to become
|
|
* available in the message queue.
|
|
*/
|
|
|
|
ret = msgsnd_wait(msgq, msgflg);
|
|
}
|
|
else if ((msgflg & IPC_NOWAIT) != 0)
|
|
{
|
|
ret = -EAGAIN;
|
|
}
|
|
}
|
|
|
|
if (ret == OK)
|
|
{
|
|
/* Now allocate the message. */
|
|
|
|
msg = (FAR struct msgbuf_s *)list_remove_head(&g_msgfreelist);
|
|
if (msg == NULL)
|
|
{
|
|
ret = -ENOMEM;
|
|
goto errout_with_critical;
|
|
}
|
|
|
|
/* Check if the message was successfully allocated */
|
|
|
|
msg->msize = msgsz;
|
|
msg->mtype = buf->mtype;
|
|
memcpy(msg->mtext, buf->mtext, msgsz);
|
|
|
|
/* Insert the new message in the message queue */
|
|
|
|
list_add_tail(&msgq->msglist, &msg->node);
|
|
|
|
msgq->nmsgs++;
|
|
|
|
if (msgq->cmn.nwaitnotempty > 0)
|
|
{
|
|
FAR struct tcb_s *rtcb = this_task();
|
|
|
|
/* Find the highest priority task that is waiting for
|
|
* this queue to be non-empty in g_waitingformqnotempty
|
|
* list. enter_critical_section() should give us sufficient
|
|
* protection since interrupts should never cause a change
|
|
* in this list
|
|
*/
|
|
|
|
btcb = (FAR struct tcb_s *)dq_remfirst(MQ_WNELIST(msgq->cmn));
|
|
|
|
/* If one was found, unblock it */
|
|
|
|
DEBUGASSERT(btcb);
|
|
|
|
if (WDOG_ISACTIVE(&btcb->waitdog))
|
|
{
|
|
wd_cancel(&btcb->waitdog);
|
|
}
|
|
|
|
msgq->cmn.nwaitnotempty--;
|
|
|
|
/* Indicate that the wait is over. */
|
|
|
|
btcb->waitobj = NULL;
|
|
|
|
/* Add the task to ready-to-run task list and
|
|
* perform the context switch if one is needed
|
|
*/
|
|
|
|
if (nxsched_add_readytorun(btcb))
|
|
{
|
|
up_switch_context(btcb, rtcb);
|
|
}
|
|
}
|
|
}
|
|
|
|
errout_with_critical:
|
|
leave_critical_section(flags);
|
|
errout:
|
|
if (ret < 0)
|
|
{
|
|
set_errno(-ret);
|
|
return ERROR;
|
|
}
|
|
|
|
return OK;
|
|
}
|