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incubator-nuttx/sched/mqueue/mq_sndinternal.c

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/****************************************************************************
* 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 <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <fcntl.h>
#include <mqueue.h>
#include <string.h>
#include <errno.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/kmalloc.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/cancelpt.h>
#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;
}
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