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Diffstat (limited to 'nuttx/sched/mq_send.c')
| -rw-r--r-- | nuttx/sched/mq_send.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/nuttx/sched/mq_send.c b/nuttx/sched/mq_send.c new file mode 100644 index 000000000..40628e924 --- /dev/null +++ b/nuttx/sched/mq_send.c @@ -0,0 +1,184 @@ +/**************************************************************************** + * 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 <mqueue.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/arch.h> + +#include "os_internal.h" +#include "mq_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: mq_send + * + * Description: + * This function adds the specificied message (msg) to the message queue + * (mqdes). The "msglen" parameter specifies the length of the message + * in bytes pointed to by "msg." This length must not exceed the maximum + * message length from the mq_getattr(). + * + * If the message queue is not full, mq_send() place the message in the + * message queue at the position indicated by the "prio" argrument. + * Messages with higher priority will be inserted before lower priority + * messages. The value of "prio" must not exceed MQ_PRIO_MAX. + * + * If the specified message queue is full and O_NONBLOCK is not set in the + * message queue, then mq_send() will block until space becomes available + * to the queue the message. + * + * If the message queue is full and O_NONBLOCK is set, the message is not + * queued and ERROR is returned. + * + * 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: + * 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. + * 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. + * + * Assumptions/restrictions: + * + ****************************************************************************/ + +int mq_send(mqd_t mqdes, const void *msg, size_t msglen, int prio) +{ + FAR msgq_t *msgq; + FAR mqmsg_t *mqmsg = NULL; + irqstate_t saved_state; + int ret = ERROR; + + /* Verify the input parameters -- setting errno appropriately + * on any failures to verify. + */ + + if (mq_verifysend(mqdes, msg, msglen, prio) != OK) + { + return ERROR; + } + + /* Get a pointer to the message queue */ + + sched_lock(); + msgq = mqdes->msgq; + + /* Allocate a message structure: + * - Immediately if we are called from an interrupt handler. + * - Immediately if the message queue is not full, or + * - After successfully waiting for the message queue to become + * non-FULL. This would fail with EAGAIN, EINTR, or ETIMEOUT. + */ + + saved_state = irqsave(); + if (up_interrupt_context() || /* In an interrupt handler */ + msgq->nmsgs < msgq->maxmsgs || /* OR Message queue not full */ + mq_waitsend(mqdes) == OK) /* OR Successfully waited for mq not full */ + { + /* Allocate the message */ + + irqrestore(saved_state); + mqmsg = mq_msgalloc(); + } + else + { + /* We cannot send the message (and didn't even try to allocate it) + * because: + * - We are not in an interrupt handler AND + * - The message queue is full AND + * - When we tried waiting, the wait was unsuccessful. + */ + + irqrestore(saved_state); + } + + /* Check if we were able to get a message structure -- this can fail + * either because we cannot send the message (and didn't bother trying + * to allocate it) or because the allocation failed. + */ + + if (mqmsg) + { + /* Yes, perform the message send. */ + + ret = mq_dosend(mqdes, mqmsg, msg, msglen, prio); + } + + sched_unlock(); + return ret; +} + |