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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 <assert.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:
* msgq - Message queue descriptor
* msg - Message to send
* msglen - The length of the message in bytes
* prio - The priority of the message
*
* Returned Value:
* On success, 0 (OK) is returned. On failure, a negated errno value is
* returned.
*
* EINVAL Either msg or msgq is NULL or the value of prio is invalid.
* EBADF Message queue opened not opened for writing.
* EMSGSIZE 'msglen' was greater than the maxmsgsize attribute of the
* message queue.
*
****************************************************************************/
#ifdef CONFIG_DEBUG_FEATURES
int nxmq_verify_send(FAR FAR struct file *mq, FAR const char *msg,
size_t msglen, unsigned int prio)
{
FAR struct inode *inode = mq->f_inode;
FAR struct mqueue_inode_s *msgq;
if (inode == NULL)
{
return -EBADF;
}
msgq = inode->i_private;
/* Verify the input parameters */
if (msg == NULL || msgq == NULL || prio >= MQ_PRIO_MAX)
{
return -EINVAL;
}
if ((mq->f_oflags & O_WROK) == 0)
{
return -EBADF;
}
if (msglen > (size_t)msgq->maxmsgsize)
{
return -EMSGSIZE;
}
return OK;
}
#endif
/****************************************************************************
* 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 list_node *mqmsg;
/* Try to get the message from the generally available free list. */
mqmsg = list_remove_head(&g_msgfree);
if (mqmsg == NULL)
{
/* 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 free list reserved for interrupt handlers */
mqmsg = list_remove_head(&g_msgfreeirq);
}
/* We were not called from an interrupt handler. */
else
{
/* If we cannot a message from the free list, then we will have to
* allocate one.
*/
mqmsg = (FAR struct list_node *)
kmm_malloc((sizeof (struct mqueue_msg_s)));
/* Check if we allocated the message */
if (mqmsg != NULL)
{
/* Yes... remember that this message was dynamically
* allocated.
*/
((FAR struct mqueue_msg_s *)mqmsg)->type = MQ_ALLOC_DYN;
}
}
}
return (FAR struct mqueue_msg_s *)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:
* msgq - Message queue descriptor
* oflags - flags from user set
*
* 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 msgq.
* EINTR The call was interrupted by a signal handler.
* ETIMEDOUT 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(FAR struct mqueue_inode_s *msgq, int oflags)
{
FAR struct tcb_s *rtcb;
bool switch_needed;
#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
/* 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 ((oflags & O_NONBLOCK) != 0)
{
/* No... We will return an error to the caller. */
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(!is_idle_task(rtcb));
/* 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 ETIMEDOUT).
*/
if (rtcb->errcode != OK)
{
return -rtcb->errcode;
}
}
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 (msgq). 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:
* msgq - 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(FAR struct mqueue_inode_s *msgq,
FAR struct mqueue_msg_s *mqmsg,
FAR const char *msg, size_t msglen, unsigned int prio)
{
FAR struct mqueue_msg_s *prev = NULL;
FAR struct mqueue_msg_s *next;
FAR struct tcb_s *btcb;
/* 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
* Search the message list to find the location to insert the new
* message. Each is list is maintained in ascending priority order.
*/
list_for_every_entry(&msgq->msglist, next, struct mqueue_msg_s, node)
{
if (prio > next->priority)
{
break;
}
else
{
prev = next;
}
}
/* Add the message at the right place */
if (prev)
{
list_add_after(&prev->node, &mqmsg->node);
}
else
{
list_add_head(&msgq->msglist, &mqmsg->node);
}
/* Increment the count of messages in the queue */
if (msgq->nmsgs++ == 0)
{
nxmq_pollnotify(msgq, POLLIN);
}
/* Check if we need to notify any tasks that are attached to the
* message queue
*/
#ifndef CONFIG_DISABLE_MQUEUE_NOTIFICATION
if (msgq->ntpid != INVALID_PROCESS_ID)
{
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;
/* Notification the client */
DEBUGVERIFY(nxsig_notification(pid, &event,
SI_MESGQ, &msgq->ntwork));
}
#endif
/* Check if any tasks are waiting for the MQ not empty event. */
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 waitfornotempty
* list. leave_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);
}
}
return OK;
}
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