/*
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* Copyright (C) 2005 Philippe Gerum <rpm@xenomai.org>.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*/
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#include <errno.h>
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#include <stdarg.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <pthread.h>
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#include <mqueue.h>
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#include <asm/xenomai/syscall.h>
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#include "internal.h"
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/**
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* @ingroup cobalt_api
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* @defgroup cobalt_api_mq Message queues
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*
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* Cobalt/POSIX message queue services
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*
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* A message queue allow exchanging data between real-time
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* threads. For a POSIX message queue, maximum message length and
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* maximum number of messages are fixed when it is created with
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* mq_open().
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*
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*@{
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*/
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/**
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* @brief Open a message queue
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*
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* This service opens the message queue named @a name.
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*
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* One of the following values should be set in @a oflags:
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* - O_RDONLY, meaning that the returned queue descriptor may only be used for
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* receiving messages;
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* - O_WRONLY, meaning that the returned queue descriptor may only be used for
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* sending messages;
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* - O_RDWR, meaning that the returned queue descriptor may be used for both
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* sending and receiving messages.
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*
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* If no message queue named @a name exists, and @a oflags has the @a O_CREAT
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* bit set, the message queue is created by this function, taking two more
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* arguments:
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* - a @a mode argument, of type @b mode_t, currently ignored;
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* - an @a attr argument, pointer to an @b mq_attr structure, specifying the
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* attributes of the new message queue.
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*
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* If @a oflags has the two bits @a O_CREAT and @a O_EXCL set and the message
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* queue alread exists, this service fails.
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*
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* If the O_NONBLOCK bit is set in @a oflags, the mq_send(), mq_receive(),
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* mq_timedsend() and mq_timedreceive() services return @a -1 with @a errno set
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* to EAGAIN instead of blocking their caller.
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*
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* The following arguments of the @b mq_attr structure at the address @a attr
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* are used when creating a message queue:
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* - @a mq_maxmsg is the maximum number of messages in the queue (128 by
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* default);
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* - @a mq_msgsize is the maximum size of each message (128 by default).
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*
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* @a name may be any arbitrary string, in which slashes have no particular
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* meaning. However, for portability, using a name which starts with a slash and
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* contains no other slash is recommended.
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*
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* @param name name of the message queue to open;
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*
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* @param oflags flags.
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*
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* @return a message queue descriptor on success;
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* @return -1 with @a errno set if:
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* - ENAMETOOLONG, the length of the @a name argument exceeds 64 characters;
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* - EEXIST, the bits @a O_CREAT and @a O_EXCL were set in @a oflags and the
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* message queue already exists;
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* - ENOENT, the bit @a O_CREAT is not set in @a oflags and the message queue
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* does not exist;
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* - ENOSPC, allocation of system memory failed, or insufficient memory available
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* from the system heap to create the queue, try increasing
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* CONFIG_XENO_OPT_SYS_HEAPSZ;
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* - EPERM, attempting to create a message queue from an invalid context;
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* - EINVAL, the @a attr argument is invalid;
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* - EMFILE, too many descriptors are currently open.
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* - EAGAIN, no registry slot available, check/raise CONFIG_XENO_OPT_REGISTRY_NRSLOTS.
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*
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* @see
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* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_open.html">
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* Specification.</a>
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*
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* @apitags{thread-unrestricted, switch-secondary}
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*/
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COBALT_IMPL(mqd_t, mq_open, (const char *name, int oflags, ...))
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{
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struct mq_attr *attr = NULL;
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mode_t mode = 0;
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va_list ap;
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int fd;
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if ((oflags & O_CREAT) != 0) {
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va_start(ap, oflags);
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mode = va_arg(ap, int); /* unused */
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attr = va_arg(ap, struct mq_attr *);
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va_end(ap);
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}
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fd = XENOMAI_SYSCALL4(sc_cobalt_mq_open, name, oflags, mode, attr);
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if (fd < 0) {
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errno = -fd;
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return (mqd_t)-1;
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}
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return (mqd_t)fd;
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}
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/**
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* @brief Close a message queue
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*
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* This service closes the message queue descriptor @a mqd. The
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* message queue is destroyed only when all open descriptors are
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* closed, and when unlinked with a call to the mq_unlink() service.
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*
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* @param mqd message queue descriptor.
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*
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* @retval 0 on success;
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* @retval -1 with @a errno set if:
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* - EBADF, @a mqd is an invalid message queue descriptor;
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* - EPERM, the caller context is invalid.
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*
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* @see
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* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_close.html">
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* Specification.</a>
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*
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* @apitags{thread-unrestricted, switch-secondary}
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*/
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COBALT_IMPL(int, mq_close, (mqd_t mqd))
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{
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int err;
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err = XENOMAI_SYSCALL1(sc_cobalt_mq_close, mqd);
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if (err) {
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errno = -err;
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return -1;
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}
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return 0;
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}
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/**
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* @brief Unlink a message queue
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*
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* This service unlinks the message queue named @a name. The message queue is
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* not destroyed until all queue descriptors obtained with the mq_open() service
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* are closed with the mq_close() service. However, after a call to this
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* service, the unlinked queue may no longer be reached with the mq_open()
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* service.
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*
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* @param name name of the message queue to be unlinked.
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*
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* @retval 0 on success;
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* @retval -1 with @a errno set if:
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* - EPERM, the caller context is invalid;
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* - ENAMETOOLONG, the length of the @a name argument exceeds 64 characters;
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* - ENOENT, the message queue does not exist.
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*
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* @see
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* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_unlink.html">
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* Specification.</a>
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*
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* @apitags{thread-unrestricted, switch-secondary}
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*/
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COBALT_IMPL(int, mq_unlink, (const char *name))
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{
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int err;
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err = XENOMAI_SYSCALL1(sc_cobalt_mq_unlink, name);
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if (!err)
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return 0;
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errno = -err;
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return -1;
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}
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/**
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* @brief Get message queue attributes
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*
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* This service stores, at the address @a attr, the attributes of the messages
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* queue descriptor @a mqd.
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*
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* The following attributes are set:
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* - @a mq_flags, flags of the message queue descriptor @a mqd;
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* - @a mq_maxmsg, maximum number of messages in the message queue;
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* - @a mq_msgsize, maximum message size;
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* - @a mq_curmsgs, number of messages currently in the queue.
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*
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* @param mqd message queue descriptor;
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*
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* @param attr address where the message queue attributes will be stored on
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* success.
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*
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* @retval 0 on success;
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* @retval -1 with @a errno set if:
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* - EBADF, @a mqd is not a valid descriptor.
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*
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* @see
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* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_getattr.html">
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* Specification.</a>
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*
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* @apitags{thread-unrestricted}
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*/
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COBALT_IMPL(int, mq_getattr, (mqd_t mqd, struct mq_attr *attr))
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{
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int err;
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err = XENOMAI_SYSCALL2(sc_cobalt_mq_getattr, mqd, attr);
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if (!err)
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return 0;
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errno = -err;
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return -1;
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}
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/**
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* @brief Set message queue attributes
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*
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* This service sets the flags of the @a mqd descriptor to the value
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* of the member @a mq_flags of the @b mq_attr structure pointed to by
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* @a attr.
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*
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* The previous value of the message queue attributes are stored at the address
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* @a oattr if it is not @a NULL.
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*
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* Only setting or clearing the O_NONBLOCK flag has an effect.
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*
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* @param mqd message queue descriptor;
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*
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* @param attr pointer to new attributes (only @a mq_flags is used);
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*
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* @param oattr if not @a NULL, address where previous message queue attributes
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* will be stored on success.
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*
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* @retval 0 on success;
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* @retval -1 with @a errno set if:
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* - EBADF, @a mqd is not a valid message queue descriptor.
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*
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* @see
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* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_setattr.html">
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* Specification.</a>
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*
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* @apitags{thread-unrestricted}
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*/
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COBALT_IMPL(int, mq_setattr, (mqd_t mqd,
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const struct mq_attr *__restrict__ attr,
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struct mq_attr *__restrict__ oattr))
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{
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int err = 0, flags;
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if (oattr) {
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err = XENOMAI_SYSCALL2(sc_cobalt_mq_getattr, mqd, oattr);
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if (err < 0)
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goto out_err;
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flags = oattr->mq_flags;
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} else {
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err = __WRAP(fcntl(mqd, F_GETFL));
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if (err < 0)
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goto out_err;
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flags = err;
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}
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flags = (flags & ~O_NONBLOCK) | (attr->mq_flags & O_NONBLOCK);
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err = __WRAP(fcntl(mqd, F_SETFL, flags));
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if (!err)
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return 0;
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out_err:
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errno = -err;
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return -1;
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}
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/**
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* Send a message to a message queue.
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*
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* If the message queue @a fd is not full, this service sends the message of
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* length @a len pointed to by the argument @a buffer, with priority @a prio. A
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* message with greater priority is inserted in the queue before a message with
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* lower priority.
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*
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* If the message queue is full and the flag @a O_NONBLOCK is not set, the
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* calling thread is suspended until the queue is not full. If the message queue
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* is full and the flag @a O_NONBLOCK is set, the message is not sent and the
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* service returns immediately a value of -1 with @a errno set to EAGAIN.
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*
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* @param q message queue descriptor;
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*
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* @param buffer pointer to the message to be sent;
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*
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* @param len length of the message;
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*
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* @param prio priority of the message.
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*
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* @return 0 and send a message on success;
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* @return -1 with no message sent and @a errno set if:
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* - EBADF, @a fd is not a valid message queue descriptor open for writing;
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* - EMSGSIZE, the message length @a len exceeds the @a mq_msgsize attribute of
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* the message queue;
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* - EAGAIN, the flag O_NONBLOCK is set for the descriptor @a fd and the message
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* queue is full;
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* - EPERM, the caller context is invalid;
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* - EINTR, the service was interrupted by a signal.
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*
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* @see
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* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_send.html">
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* Specification.</a>
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*
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* @apitags{xthread-only, switch-primary}
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*/
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COBALT_IMPL(int, mq_send, (mqd_t q, const char *buffer, size_t len, unsigned prio))
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{
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int err, oldtype;
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pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
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#ifdef __USE_TIME_BITS64
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err = XENOMAI_SYSCALL5(sc_cobalt_mq_timedsend64,
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q, buffer, len, prio, NULL);
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#else
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err = XENOMAI_SYSCALL5(sc_cobalt_mq_timedsend,
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q, buffer, len, prio, NULL);
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#endif
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pthread_setcanceltype(oldtype, NULL);
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if (!err)
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return 0;
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errno = -err;
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return -1;
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}
|
|
/**
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* Attempt, during a bounded time, to send a message to a message queue.
|
*
|
* This service is equivalent to mq_send(), except that if the message queue is
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* full and the flag @a O_NONBLOCK is not set for the descriptor @a fd, the
|
* calling thread is only suspended until the timeout specified by @a
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* abs_timeout expires.
|
*
|
* @param q message queue descriptor;
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*
|
* @param buffer pointer to the message to be sent;
|
*
|
* @param len length of the message;
|
*
|
* @param prio priority of the message;
|
*
|
* @param timeout the timeout, expressed as an absolute value of the
|
* CLOCK_REALTIME clock.
|
*
|
* @return 0 and send a message on success;
|
* @return -1 with no message sent and @a errno set if:
|
* - EBADF, @a fd is not a valid message queue descriptor open for writing;
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* - EMSGSIZE, the message length exceeds the @a mq_msgsize attribute of the
|
* message queue;
|
* - EAGAIN, the flag O_NONBLOCK is set for the descriptor @a fd and the message
|
* queue is full;
|
* - EPERM, the caller context is invalid;
|
* - ETIMEDOUT, the specified timeout expired;
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* - EINTR, the service was interrupted by a signal.
|
*
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* @see
|
* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_timedsend.html">
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* Specification.</a>
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*
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* @apitags{xthread-only, switch-primary}
|
*/
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COBALT_IMPL(int, mq_timedsend, (mqd_t q,
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const char *buffer,
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size_t len,
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unsigned prio, const struct timespec *timeout))
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{
|
int err, oldtype;
|
|
if (timeout == NULL)
|
return -EFAULT;
|
|
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
|
|
err = XENOMAI_SYSCALL5(sc_cobalt_mq_timedsend,
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q, buffer, len, prio, timeout);
|
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pthread_setcanceltype(oldtype, NULL);
|
|
if (!err)
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return 0;
|
|
errno = -err;
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return -1;
|
}
|
|
/**
|
* Receive a message from a message queue.
|
*
|
* If the message queue @a fd is not empty and if @a len is greater than the @a
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* mq_msgsize of the message queue, this service copies, at the address
|
* @a buffer, the queued message with the highest priority.
|
*
|
* If the queue is empty and the flag @a O_NONBLOCK is not set for the
|
* descriptor @a fd, the calling thread is suspended until some message is sent
|
* to the queue. If the queue is empty and the flag @a O_NONBLOCK is set for the
|
* descriptor @a fd, this service returns immediately a value of -1 with @a
|
* errno set to EAGAIN.
|
*
|
* @param q the queue descriptor;
|
*
|
* @param buffer the address where the received message will be stored on
|
* success;
|
*
|
* @param len @a buffer length;
|
*
|
* @param prio address where the priority of the received message will be
|
* stored on success.
|
*
|
* @return the message length, and copy a message at the address @a buffer on
|
* success;
|
* @return -1 with no message unqueued and @a errno set if:
|
* - EBADF, @a fd is not a valid descriptor open for reading;
|
* - EMSGSIZE, the length @a len is lesser than the message queue @a mq_msgsize
|
* attribute;
|
* - EAGAIN, the queue is empty, and the flag @a O_NONBLOCK is set for the
|
* descriptor @a fd;
|
* - EPERM, the caller context is invalid;
|
* - EINTR, the service was interrupted by a signal.
|
*
|
* @see
|
* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_receive.html">
|
* Specification.</a>
|
*
|
* @apitags{xthread-only, switch-primary}
|
*/
|
COBALT_IMPL(ssize_t, mq_receive, (mqd_t q, char *buffer, size_t len, unsigned *prio))
|
{
|
ssize_t rlen = (ssize_t) len;
|
int err, oldtype;
|
|
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
|
|
err = XENOMAI_SYSCALL5(sc_cobalt_mq_timedreceive,
|
q, buffer, &rlen, prio, NULL);
|
|
pthread_setcanceltype(oldtype, NULL);
|
|
if (!err)
|
return rlen;
|
|
errno = -err;
|
return -1;
|
}
|
|
/**
|
* Attempt, during a bounded time, to receive a message from a message queue.
|
*
|
* This service is equivalent to mq_receive(), except that if the flag @a
|
* O_NONBLOCK is not set for the descriptor @a fd and the message queue is
|
* empty, the calling thread is only suspended until the timeout @a abs_timeout
|
* expires.
|
*
|
* @param q the queue descriptor;
|
*
|
* @param buffer the address where the received message will be stored on
|
* success;
|
*
|
* @param len @a buffer length;
|
*
|
* @param prio address where the priority of the received message will be
|
* stored on success.
|
*
|
* @param timeout the timeout, expressed as an absolute value of the
|
* CLOCK_REALTIME clock.
|
*
|
* @return the message length, and copy a message at the address @a buffer on
|
* success;
|
* @return -1 with no message unqueued and @a errno set if:
|
* - EBADF, @a fd is not a valid descriptor open for reading;
|
* - EMSGSIZE, the length @a len is lesser than the message queue @a mq_msgsize
|
* attribute;
|
* - EAGAIN, the queue is empty, and the flag @a O_NONBLOCK is set for the
|
* descriptor @a fd;
|
* - EPERM, the caller context is invalid;
|
* - EINTR, the service was interrupted by a signal;
|
* - ETIMEDOUT, the specified timeout expired.
|
*
|
* @see
|
* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_timedreceive.html">
|
* Specification.</a>
|
*
|
* @apitags{xthread-only, switch-primary}
|
*/
|
COBALT_IMPL(ssize_t, mq_timedreceive, (mqd_t q,
|
char *__restrict__ buffer,
|
size_t len,
|
unsigned *__restrict__ prio,
|
const struct timespec * __restrict__ timeout))
|
{
|
ssize_t rlen = (ssize_t) len;
|
int err, oldtype;
|
|
if (timeout == NULL)
|
return -EFAULT;
|
|
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
|
|
#ifdef __USE_TIME_BITS64
|
err = XENOMAI_SYSCALL5(sc_cobalt_mq_timedreceive64,
|
q, buffer, &rlen, prio, timeout);
|
#else
|
err = XENOMAI_SYSCALL5(sc_cobalt_mq_timedreceive,
|
q, buffer, &rlen, prio, timeout);
|
#endif
|
|
pthread_setcanceltype(oldtype, NULL);
|
|
if (!err)
|
return rlen;
|
|
errno = -err;
|
return -1;
|
}
|
|
/**
|
* @brief Enable notification on message arrival
|
*
|
* If @a evp is not @a NULL and is the address of a @b sigevent
|
* structure with the @a sigev_notify member set to SIGEV_SIGNAL, the
|
* current thread will be notified by a signal when a message is sent
|
* to the message queue @a mqd, the queue is empty, and no thread is
|
* blocked in call to mq_receive() or mq_timedreceive(). After the
|
* notification, the thread is unregistered.
|
*
|
* If @a evp is @a NULL or the @a sigev_notify member is SIGEV_NONE,
|
* the current thread is unregistered.
|
*
|
* Only one thread may be registered at a time.
|
*
|
* If the current thread is not a Cobalt thread (created with
|
* pthread_create()), this service fails.
|
*
|
* @param mqd message queue descriptor;
|
*
|
* @param evp pointer to an event notification structure.
|
*
|
* @retval 0 on success;
|
* @retval -1 with @a errno set if:
|
* - EINVAL, @a evp is invalid;
|
* - EPERM, the caller context is invalid;
|
* - EBADF, @a mqd is not a valid message queue descriptor;
|
* - EBUSY, another thread is already registered.
|
*
|
* @see
|
* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/mq_notify.html">
|
* Specification.</a>
|
*
|
* @apitags{xthread-only, switch-primary}
|
*/
|
COBALT_IMPL(int, mq_notify, (mqd_t mqd, const struct sigevent *evp))
|
{
|
int err;
|
|
err = XENOMAI_SYSCALL2(sc_cobalt_mq_notify, mqd, evp);
|
if (err) {
|
errno = -err;
|
return -1;
|
}
|
|
return 0;
|
}
|
|
/** @}*/
|
