/****************************************************************************
* sched/mq_send.c
*
* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* 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/kmalloc.h>
#include <nuttx/arch.h>
#include "os_internal.h"
#ifndef CONFIG_DISABLE_SIGNALS
# include "sig_internal.h"
#endif
#include "mq_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mq_verifysend
*
* Description:
* This is internal, common logic shared by both mq_send and mq_timesend.
* This function verifies the input parameters that are common to both
* functions.
*
* Parameters:
* mqdes - Message queue descriptor
* msg - Message to send
* msglen - The length of the message in bytes
* prio - The priority of the message
*
* Return Value:
* One success, 0 (OK) is returned. On failure, -1 (ERROR) is returned and
* the errno is set appropriately:
*
* 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.
*
* Assumptions:
*
****************************************************************************/
int mq_verifysend(mqd_t mqdes, const void *msg, size_t msglen, int prio)
{
/* Verify the input parameters */
if (!msg || !mqdes || prio < 0 || prio > MQ_PRIO_MAX)
{
set_errno(EINVAL);
return ERROR;
}
if ((mqdes->oflags & O_WROK) == 0)
{
set_errno(EPERM);
return ERROR;
}
if (msglen < 0 || msglen > (size_t)mqdes->msgq->maxmsgsize)
{
set_errno(EMSGSIZE);
return ERROR;
}
return OK;
}
/****************************************************************************
* Name: mq_msgalloc
*
* Description:
* The mq_msgalloc 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.
*
* Inputs:
* None
*
* Return Value:
* A reference to the allocated msg structure. On a failure to allocate,
* this function PANICs.
*
****************************************************************************/
FAR mqmsg_t *mq_msgalloc(void)
{
FAR mqmsg_t *mqmsg;
irqstate_t saved_state;
/* 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 mqmsg_t*)sq_remfirst(&g_msgfree);
if (!mqmsg)
{
/* Try the free list reserved for interrupt handlers */
mqmsg = (FAR mqmsg_t*)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.
*/
saved_state = irqsave();
mqmsg = (FAR mqmsg_t*)sq_remfirst(&g_msgfree);
irqrestore(saved_state);
/* If we cannot a message from the free list, then we will have to allocate one. */
if (!mqmsg)
{
mqmsg = (FAR mqmsg_t *)kmalloc((sizeof (mqmsg_t)));
/* Check if we got an allocated message */
if (mqmsg)
{
mqmsg->type = MQ_ALLOC_DYN;
}
/* No? We are dead */
else
{
sdbg("Out of messages\n");
PANIC((uint32_t)OSERR_OUTOFMESSAGES);
}
}
}
return mqmsg;
}
/****************************************************************************
* Name: mq_waitsend
*
* Description:
* This is internal, common logic shared by both mq_send and mq_timesend.
* This function waits until the message queue is not full.
*
* Parameters:
* mqdes - Message queue descriptor
*
* Return 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 empty, 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 mq_verifysend().
* - Interrupts are disabled.
*
****************************************************************************/
int mq_waitsend(mqd_t mqdes)
{
FAR _TCB *rtcb;
FAR msgq_t *msgq;
/* 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. */
set_errno(EAGAIN);
return ERROR;
}
/* Yes... We will not return control until the message queue is
* available or we receive a signal or at timout occurs.
*/
else
{
/* Loop until there are fewer than max allowable messages in the
* receiving message queue
*/
while (msgq->nmsgs >= msgq->maxmsgs)
{
/* Block until the message queue is no longer full.
* When we are unblocked, we will try again
*/
rtcb = (FAR _TCB*)g_readytorun.head;
rtcb->msgwaitq = msgq;
msgq->nwaitnotfull++;
set_errno(OK);
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
* errno value (should be EINTR or ETIMEOUT).
*/
if (get_errno() != OK)
{
return ERROR;
}
}
}
}
return OK;
}
/****************************************************************************
* Name: mq_dosend
*
* Description:
* This is internal, common logic shared by both mq_send and mq_timesend.
* This function adds the specificied 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.
*
* Parameters:
* mqdes - Message queue descriptor
* msg - Message to send
* msglen - The length of the message in bytes
* prio - The priority of the message
*
* Return Value:
* This function always returns OK.
*
* Assumptions/restrictions:
*
****************************************************************************/
int mq_dosend(mqd_t mqdes, FAR mqmsg_t *mqmsg, const void *msg, size_t msglen, int prio)
{
FAR _TCB *btcb;
FAR msgq_t *msgq;
FAR mqmsg_t *next;
FAR mqmsg_t *prev;
irqstate_t saved_state;
/* 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((void*)mqmsg->mail, (const void*)msg, msglen);
/* Insert the new message in the message queue */
saved_state = irqsave();
/* 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 mqmsg_t*)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++;
irqrestore(saved_state);
/* Check if we need to notify any tasks that are attached to the
* message queue
*/
#ifndef CONFIG_DISABLE_SIGNALS
if (msgq->ntmqdes)
{
/* Remove the message notification data from the message queue. */
#ifdef CONFIG_CAN_PASS_STRUCTS
union sigval value = msgq->ntvalue;
#else
void *sival_ptr = msgq->ntvalue.sival_ptr;
#endif
int signo = msgq->ntsigno;
int pid = msgq->ntpid;
/* Detach the notification */
msgq->ntpid = INVALID_PROCESS_ID;
msgq->ntsigno = 0;
msgq->ntvalue.sival_int = 0;
msgq->ntmqdes = NULL;
/* Queue the signal -- What if this returns an error? */
#ifdef CONFIG_CAN_PASS_STRUCTS
sig_mqnotempty(pid, signo, value);
#else
sig_mqnotempty(pid, signo, sival_ptr);
#endif
}
#endif
/* Check if any tasks are waiting for the MQ not empty event. */
saved_state = irqsave();
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 sufficent protection since
* interrupts should never cause a change in this list
*/
for (btcb = (FAR _TCB*)g_waitingformqnotempty.head;
btcb && btcb->msgwaitq != msgq;
btcb = btcb->flink);
/* If one was found, unblock it */
if (!btcb)
{
PANIC(OSERR_MQNONEMPTYCOUNT);
}
else
{
btcb->msgwaitq = NULL;
msgq->nwaitnotempty--;
up_unblock_task(btcb);
}
}
irqrestore(saved_state);
sched_unlock();
return OK;
}
