5f5d5496d9
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@165 42af7a65-404d-4744-a932-0658087f49c3
456 lines
13 KiB
C
456 lines
13 KiB
C
/************************************************************
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* mq_send.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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************************************************************/
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/************************************************************
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* Included Files
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************************************************************/
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#include <nuttx/compiler.h>
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#include <nuttx/kmalloc.h>
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#include <sys/types.h> /* uint32, etc. */
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#include <fcntl.h>
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#include <mqueue.h>
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#include <string.h>
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#include <errno.h>
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#include <sched.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include "os_internal.h"
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#ifndef CONFIG_DISABLE_SIGNALS
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# include "sig_internal.h"
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#endif
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#include "mq_internal.h"
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/************************************************************
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* Definitions
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************************************************************/
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/************************************************************
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* Private Type Declarations
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************************************************************/
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/************************************************************
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* Global Variables
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************************************************************/
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/************************************************************
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* Private Variables
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************************************************************/
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/************************************************************
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* Function: mq_msgalloc
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*
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* Description:
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* The mq_msgalloc function will get a free message for use
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* by the operating system. The message will be allocated
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* from the g_msgfree list.
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*
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* If the list is empty AND the message is NOT being
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* allocated from the interrupt level, then the message
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* will be allocated. If a message cannot be obtained,
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* the operating system is dead and therefore cannot
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* continue.
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*
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* If the list is empty AND the message IS being allocated
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* from the interrupt level. This function will attempt to
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* get a message from the g_msgfreeirq list. If this is
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* unsuccessful, the calling interrupt handler will be
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* notified.
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*
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* Inputs:
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* None
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*
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* Return Value:
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* A reference to the allocated msg structure
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*
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************************************************************/
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FAR mqmsg_t *mq_msgalloc(void)
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{
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FAR mqmsg_t *mqmsg;
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irqstate_t saved_state;
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/* If we were called from an interrupt handler, then try to
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* get the message from generally available list of messages.
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* If this fails, then try the list of messages reserved for
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* interrupt handlers
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*/
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if (up_interrupt_context())
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{
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/* Try the general free list */
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mqmsg = (FAR mqmsg_t*)sq_remfirst(&g_msgfree);
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if (!mqmsg)
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{
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/* Try the free list reserved for interrupt handlers */
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mqmsg = (FAR mqmsg_t*)sq_remfirst(&g_msgfreeirq);
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}
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}
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/* We were not called from an interrupt handler. */
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else
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{
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/* Try to get the message from the generally available free list.
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* Disable interrupts -- we might be called from an interrupt handler.
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*/
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saved_state = irqsave();
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mqmsg = (FAR mqmsg_t*)sq_remfirst(&g_msgfree);
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irqrestore(saved_state);
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/* If we cannot a message from the free list, then we will have to allocate one. */
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if (!mqmsg)
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{
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mqmsg = (FAR mqmsg_t *)kmalloc((sizeof (mqmsg_t)));
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/* Check if we got an allocated message */
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if (mqmsg)
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{
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mqmsg->type = MQ_ALLOC_DYN;
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}
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/* No? We are dead */
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else
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{
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dbg("Out of messages\n");
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PANIC((uint32)OSERR_OUTOFMESSAGES);
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}
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}
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}
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return(mqmsg);
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}
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/************************************************************
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* Private Functions
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************************************************************/
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/************************************************************
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* Public Functions
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************************************************************/
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/************************************************************
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* Function: mq_send
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*
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* Description:
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* This function adds the specificied message (msg) to the
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* message queue (mqdes). The "msglen" parameter specifies
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* the length of the message in bytes pointed to by "msg."
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* This length must not exceed the maximum message length
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* from the mq_getattr().
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*
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* If the message queue is not full, mq_send() place the
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* message in the message queue at the position indicated
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* by the "prio" argrument. Messages with higher priority
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* will be inserted before lower priority messages. The
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* value of "prio" must not exceed MQ_PRIO_MAX.
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*
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* If the specified message queue is full and O_NONBLOCK
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* is not set in the message queue, then mq_send() will
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* block until space becomes available to the queue the
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* message.
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*
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* If the message queue is full and O_NONBLOCK is set,
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* the message is not queued and ERROR is returned.
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*
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* Parameters:
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* mqdes - Message queue descriptor
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* msg - Message to send
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* msglen - The length of the message in bytes
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* prio - The priority of the message
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*
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* Return Value:
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* On success, mq_send() returns 0 (OK); on error, -1 (ERROR)
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* is returned, with errno set to indicate the error:
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*
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* EAGAIN The queue was empty, and the O_NONBLOCK flag was
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* set for the message queue description referred to
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* by mqdes.
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* EINVAL Either msg or mqdes is NULL or the value of prio
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* is invalid.
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* EPERM Message queue opened not opened for writing.
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* EMSGSIZE 'msglen' was greater than the maxmsgsize attribute
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* of the message queue.
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* EINTR The call was interrupted by a signal handler.
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*
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* Assumptions/restrictions:
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*
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************************************************************/
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int mq_send(mqd_t mqdes, const void *msg, size_t msglen, int prio)
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{
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FAR _TCB *rtcb;
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FAR _TCB *btcb;
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FAR msgq_t *msgq;
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FAR mqmsg_t *curr;
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FAR mqmsg_t *next;
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FAR mqmsg_t *prev;
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irqstate_t saved_state;
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int ret = ERROR;
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/* Verify the input parameters */
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if (!msg || !mqdes || prio < 0 || prio > MQ_PRIO_MAX)
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{
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*get_errno_ptr() = EINVAL;
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return ERROR;
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}
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if ((mqdes->oflags & O_WROK) == 0)
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{
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*get_errno_ptr() = EPERM;
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return ERROR;
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}
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if (msglen < 0 || msglen > (size_t)mqdes->msgq->maxmsgsize)
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{
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*get_errno_ptr() = EMSGSIZE;
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return ERROR;
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}
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/* Get a pointer to the message queue */
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sched_lock();
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msgq = mqdes->msgq;
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/* If we are sending a message from an interrupt handler, then
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* try to get message structure unconditionally.
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*/
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saved_state = irqsave();
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if (up_interrupt_context())
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{
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curr = mq_msgalloc();
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}
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/* Otherwise, arbitrarily limit the number of messages in the
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* queue to the value determined when the message queue was opened.
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* This makes us more POSIX-like as well as prohibits one slow
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* responding task from consuming all available memory.
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*/
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else if (msgq->nmsgs >= msgq->maxmsgs)
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{
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/* Should we block until there is sufficient space in the
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* message queue?
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*/
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if ((mqdes->oflags & O_NONBLOCK) != 0)
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{
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/* No... We will return an error to the caller. */
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*get_errno_ptr() = EAGAIN;
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curr = NULL;
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}
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/* Yes... We will not return control until the message queue is
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* available.
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*/
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else
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{
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boolean interrupted = FALSE;
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/* Loop until there are fewer than max allowable messages in the
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* receiving message queue
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*/
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while (msgq->nmsgs >= msgq->maxmsgs)
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{
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/* Block until the message queue is no longer full.
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* When we are unblocked, we will try again
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*/
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rtcb = (FAR _TCB*)g_readytorun.head;
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rtcb->msgwaitq = msgq;
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(msgq->nwaitnotfull)++;
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*get_errno_ptr() = OK;
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up_block_task(rtcb, TSTATE_WAIT_MQNOTFULL);
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/* When we resume at this point, either (1) the message queue
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* is no longer empty, or (2) the wait has been interrupted by
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* a signal. We can detect the latter case be examining the
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* errno value (should be EINTR).
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*/
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if (*get_errno_ptr() != OK)
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{
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interrupted = TRUE;
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break;
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}
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}
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/* If we were not interrupted, then it should be okay to add
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* a message to the receiving message queue now.
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*/
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if (!interrupted)
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{
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curr = mq_msgalloc();
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}
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}
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}
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/* We are not in an interrupt handler and the receiving message queue
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* is not full
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*/
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else
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{
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/* Just allocate a message */
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curr = mq_msgalloc();
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}
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irqrestore(saved_state);
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/* Check if we were able to get a message structure */
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if (curr)
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{
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/* Construct the current message header info */
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curr->priority = (ubyte)prio;
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curr->msglen = (ubyte)msglen;
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/* Copy the message data into the message */
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memcpy((void*)curr->mail, (const void*)msg, msglen);
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/* Insert the new message in the message queue */
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saved_state = irqsave();
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/* Search the message list to find the location to insert the new
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* message. Each is list is maintained in ascending priority order.
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*/
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for (prev = NULL, next = (FAR mqmsg_t*)msgq->msglist.head;
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next && prio <= next->priority;
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prev = next, next = next->next);
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/* Add the message at the right place */
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if (prev)
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{
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sq_addafter((FAR sq_entry_t*)prev, (FAR sq_entry_t*)curr,
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&msgq->msglist);
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}
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else
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{
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sq_addfirst((FAR sq_entry_t*)curr, &msgq->msglist);
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}
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/* Increment the count of message in the queue */
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msgq->nmsgs++;
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irqrestore(saved_state);
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/* Check if we need to notify any tasks that are attached to the
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* message queue
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*/
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#ifndef CONFIG_DISABLE_SIGNALS
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if (msgq->ntmqdes)
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{
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/* Remove the message notification data from the message queue. */
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#ifdef CONFIG_CAN_PASS_STRUCTS
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union sigval value = msgq->ntvalue;
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#else
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void *sival_ptr = msgq->ntvalue.sival_ptr;
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#endif
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int signo = msgq->ntsigno;
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int pid = msgq->ntpid;
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/* Detach the notification */
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msgq->ntpid = INVALID_PROCESS_ID;
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msgq->ntsigno = 0;
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msgq->ntvalue.sival_int = 0;
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msgq->ntmqdes = NULL;
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/* Queue the signal -- What if this returns an error? */
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#ifdef CONFIG_CAN_PASS_STRUCTS
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sig_mqnotempty(pid, signo, value);
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#else
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sig_mqnotempty(pid, signo, sival_ptr);
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#endif
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}
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#endif
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/* Check if any tasks are waiting for the MQ not empty event. */
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saved_state = irqsave();
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if (msgq->nwaitnotempty > 0)
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{
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/* Find the highest priority task that is waiting for
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* this queue to be non-empty in g_waitingformqnotempty
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* list. sched_lock() should give us sufficent protection since
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* interrupts should never cause a change in this list
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*/
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for (btcb = (FAR _TCB*)g_waitingformqnotempty.head;
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btcb && btcb->msgwaitq != msgq;
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btcb = btcb->flink);
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/* If one was found, unblock it */
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if (!btcb)
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{
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PANIC(OSERR_MQNONEMPTYCOUNT);
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}
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else
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{
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btcb->msgwaitq = NULL;
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msgq->nwaitnotempty--;
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up_unblock_task(btcb);
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}
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}
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irqrestore(saved_state);
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ret = OK;
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}
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sched_unlock();
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return(ret);
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}
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