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Diffstat (limited to 'nuttx/sched/mq_open.c')
| -rw-r--r-- | nuttx/sched/mq_open.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/nuttx/sched/mq_open.c b/nuttx/sched/mq_open.c new file mode 100644 index 000000000..5e1b9b137 --- /dev/null +++ b/nuttx/sched/mq_open.c @@ -0,0 +1,236 @@ +/**************************************************************************** + * sched/mq_open.c + * + * Copyright (C) 2007-2009, 2011 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 <stdarg.h> +#include <mqueue.h> +#include <fcntl.h> +#include <string.h> +#include <sched.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/kmalloc.h> + +#include "os_internal.h" +#include "mq_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: mq_open + * + * Description: + * This function establish a connection between a named message queue and + * the calling task. After a successful call of mq_open(), the task can + * reference the message queue using the address returned by the call. The + * message queue remains usable until it is closed by a successful call to + * mq_close(). + * + * Parameters: + * mq_name - Name of the queue to open + * oflags - open flags + * Optional parameters. When the O_CREAT flag is specified, two optional + * parameters are expected: + * + * 1. mode_t mode (ignored), and + * 2. struct mq_attr *attr. The mq_maxmsg attribute + * is used at the time that the message queue is + * created to determine the maximum number of + * messages that may be placed in the message queue. + * + * Return Value: + * A message queue descriptor or -1 (ERROR) + * + * Assumptions: + * + ****************************************************************************/ + +mqd_t mq_open(const char *mq_name, int oflags, ...) +{ + FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head; + FAR msgq_t *msgq; + mqd_t mqdes = NULL; + va_list arg; /* Points to each un-named argument */ + mode_t mode; /* MQ creation mode parameter (ignored) */ + struct mq_attr *attr; /* MQ creation attributes */ + int namelen; /* Length of MQ name */ + + /* Make sure that a non-NULL name is supplied */ + + if (mq_name) + { + sched_lock(); + namelen = strlen(mq_name); + if (namelen > 0) + { + /* See if the message queue already exists */ + + msgq = mq_findnamed(mq_name); + if (msgq) + { + /* It does. Check if the caller wanted to create a new + * message queue with this name (i.e., O_CREAT|O_EXCL) + */ + + if ((oflags & O_CREAT) == 0 || (oflags & O_EXCL) == 0) + { + /* Create a message queue descriptor for the TCB */ + + mqdes = mq_descreate(rtcb, msgq, oflags); + if (mqdes) + { + /* Allow a new connection to the message queue */ + + msgq->nconnect++; + } + } + } + + /* It doesn't exist. Should we create one? */ + + else if ((oflags & O_CREAT) != 0) + { + /* Allocate memory for the new message queue. The size to + * allocate is the size of the msgq_t header plus the size + * of the message queue name+1. + */ + + msgq = (FAR msgq_t*)kzalloc(SIZEOF_MQ_HEADER + namelen + 1); + if (msgq) + { + /* Create a message queue descriptor for the TCB */ + + mqdes = mq_descreate(rtcb, msgq, oflags); + if (mqdes) + { + /* Set up to get the optional arguments needed to create + * a message queue. + */ + + va_start(arg, oflags); + mode = va_arg(arg, mode_t); + attr = va_arg(arg, struct mq_attr*); + + /* Initialize the new named message queue */ + + sq_init(&msgq->msglist); + if (attr) + { + msgq->maxmsgs = (int16_t)attr->mq_maxmsg; + if (attr->mq_msgsize <= MQ_MAX_BYTES) + { + msgq->maxmsgsize = (int16_t)attr->mq_msgsize; + } + else + { + msgq->maxmsgsize = MQ_MAX_BYTES; + } + } + else + { + msgq->maxmsgs = MQ_MAX_MSGS; + msgq->maxmsgsize = MQ_MAX_BYTES; + } + + msgq->nconnect = 1; +#ifndef CONFIG_DISABLE_SIGNALS + msgq->ntpid = INVALID_PROCESS_ID; +#endif + strcpy(msgq->name, mq_name); + + /* Add the new message queue to the list of + * message queues + */ + + sq_addlast((FAR sq_entry_t*)msgq, &g_msgqueues); + + /* Clean-up variable argument stuff */ + + va_end(arg); + } + else + { + /* Deallocate the msgq structure. Since it is + * uninitialized, mq_deallocate() is not used. + */ + + sched_free(msgq); + } + } + } + } + + sched_unlock(); + } + + if (mqdes == NULL) + { + return (mqd_t)ERROR; + } + else + { + return mqdes; + } +} |