nuttx/include/nuttx/mqueue.h

411 lines
16 KiB
C

/****************************************************************************
* include/nuttx/mqueue.h
*
* Copyright (C) 2007, 2009, 2011, 2014-2017 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.
*
****************************************************************************/
#ifndef ___INCLUDE_NUTTX_MQUEUE_H
#define ___INCLUDE_NUTTX_MQUEUE_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <mqueue.h>
#include <queue.h>
#include <signal.h>
#if CONFIG_MQ_MAXMSGSIZE > 0
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Most internal nxmq_* interfaces are not available in the user space in
* PROTECTED and KERNEL builds. In that context, the application message
* queu interfaces must be used. The differences between the two sets of
* interfaces are: (1) the nxmq_* interfaces do not cause cancellation
* points and (2) they do not modify the errno variable.
*
* This is only important when compiling libraries (libc or libnx) that are
* used both by the OS (libkc.a and libknx.a) or by the applications
* (libuc.a and libunx.a). The that case, the correct interface must be
* used for the build context.
*
* The interfaces sigtimedwait(), sigwait(), sigwaitinfo(), sleep(),
* nanosleep(), and usleep() are cancellation points.
*
* REVISIT: The fact that these interfaces are cancellation points is an
* issue and may cause violations: It use of these internally will cause
* the calling function to become a cancellation points!
*/
#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
# define _MQ_SEND(d,m,l,p) nxmq_send(d,m,l,p)
# define _MQ_TIMEDSEND(d,m,l,p,t) nxmq_timedsend(d,m,l,p,t)
# define _MQ_RECEIVE(d,m,l,p) nxmq_receive(d,m,l,p)
# define _MQ_TIMEDRECIEVE(d,m,l,p,t) nxmq_timedreceive(d,m,l,p,t)
# define _MQ_GETERRNO(r) (-(r))
# define _MQ_SETERRNO(r) set_errno(-(r))
# define _MQ_GETERRVAL(r) (r)
#else
# define _MQ_SEND(d,m,l,p) mq_send(d,m,l,p)
# define _MQ_TIMEDSEND(d,m,l,p,t) mq_timedsend(d,m,l,p,t)
# define _MQ_RECEIVE(d,m,l,p) mq_receive(d,m,l,p)
# define _MQ_TIMEDRECIEVE(d,m,l,p,t) mq_timedreceive(d,m,l,p,t)
# define _MQ_GETERRNO(r) errno
# define _MQ_SETERRNO(r)
# define _MQ_GETERRVAL(r) (-errno)
#endif
/****************************************************************************
* Public Type Declarations
****************************************************************************/
/* This structure defines a message queue */
struct mq_des; /* forward reference */
struct mqueue_inode_s
{
FAR struct inode *inode; /* Containing inode */
sq_queue_t msglist; /* Prioritized message list */
int16_t maxmsgs; /* Maximum number of messages in the queue */
int16_t nmsgs; /* Number of message in the queue */
int16_t nwaitnotfull; /* Number tasks waiting for not full */
int16_t nwaitnotempty; /* Number tasks waiting for not empty */
#if CONFIG_MQ_MAXMSGSIZE < 256
uint8_t maxmsgsize; /* Max size of message in message queue */
#else
uint16_t maxmsgsize; /* Max size of message in message queue */
#endif
#ifndef CONFIG_DISABLE_SIGNALS
FAR struct mq_des *ntmqdes; /* Notification: Owning mqdes (NULL if none) */
pid_t ntpid; /* Notification: Receiving Task's PID */
struct sigevent ntevent; /* Notification description */
#endif
};
/* This describes the message queue descriptor that is held in the
* task's TCB
*/
struct mq_des
{
FAR struct mq_des *flink; /* Forward link to next message descriptor */
FAR struct mqueue_inode_s *msgq; /* Pointer to associated message queue */
int oflags; /* Flags set when message queue was opened */
};
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
struct tcb_s; /* Forward reference */
struct mq_attr; /* Forward reference */
struct timespec; /* Forward reference */
struct task_group_s; /* Forward reference */
/****************************************************************************
* Name: nxmq_send
*
* Description:
* This function adds the specified message (msg) to the message queue
* (mqdes). This is an internal OS interface. It is functionally
* equivalent to mq_send() except that:
*
* - It is not a cancellaction point, and
* - It does not modify the errno value.
*
* See comments with mq_send() for a more complete description of the
* behavior of this function
*
* Input Parameters:
* mqdes - Message queue descriptor
* msg - Message to send
* msglen - The length of the message in bytes
* prio - The priority of the message
*
* Returned Value:
* This is an internal OS interface and should not be used by applications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
* (see mq_send() for the list list valid return values).
*
****************************************************************************/
int nxmq_send(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio);
/****************************************************************************
* Name: nxmq_timedsend
*
* Description:
* This function adds the specified message (msg) to the message queue
* (mqdes). nxmq_timedsend() behaves just like mq_send(), except that if
* the queue is full and the O_NONBLOCK flag is not enabled for the
* message queue description, then abstime points to a structure which
* specifies a ceiling on the time for which the call will block.
*
* nxmq_timedsend() is functionally equivalent to mq_timedsend() except
* that:
*
* - It is not a cancellaction point, and
* - It does not modify the errno value.
*
* See comments with mq_timedsend() for a more complete description of the
* behavior of this function
*
* Input Parameters:
* mqdes - Message queue descriptor
* msg - Message to send
* msglen - The length of the message in bytes
* prio - The priority of the message
* abstime - the absolute time to wait until a timeout is decleared
*
* Returned Value:
* This is an internal OS interface and should not be used by applications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
* (see mq_timedsend() for the list list valid return values).
*
* 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.
*
****************************************************************************/
int nxmq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio,
FAR const struct timespec *abstime);
/****************************************************************************
* Name: nxmq_receive
*
* Description:
* This function receives the oldest of the highest priority messages
* from the message queue specified by "mqdes." This is an internal OS
* interface. It is functionally equivalent to mq_receive except that:
*
* - It is not a cancellaction point, and
* - It does not modify the errno value.
*
* See comments with mq_receive() for a more complete description of the
* behavior of this function
*
* Input Parameters:
* mqdes - Message Queue Descriptor
* msg - Buffer to receive the message
* msglen - Size of the buffer in bytes
* prio - If not NULL, the location to store message priority.
*
* Returned Value:
* This is an internal OS interface and should not be used by applications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
* (see mq_receive() for the list list valid return values).
*
****************************************************************************/
ssize_t nxmq_receive(mqd_t mqdes, FAR char *msg, size_t msglen,
FAR int *prio);
/****************************************************************************
* Name: nxmq_timedreceive
*
* Description:
* This function receives the oldest of the highest priority messages from
* the message queue specified by "mqdes." If the message queue is empty
* and O_NONBLOCK was not set, nxmq_timedreceive() will block until a
* message is added to the message queue (or until a timeout occurs).
*
* nxmq_timedreceive() is an internal OS interface. It is functionally
* equivalent to mq_timedreceive() except that:
*
* - It is not a cancellaction point, and
* - It does not modify the errno value.
*
* See comments with mq_timedreceive() for a more complete description of
* the behavior of this function
*
* Input Parameters:
* mqdes - Message Queue Descriptor
* msg - Buffer to receive the message
* msglen - Size of the buffer in bytes
* prio - If not NULL, the location to store message priority.
* abstime - the absolute time to wait until a timeout is declared.
*
* Returned Value:
* This is an internal OS interface and should not be used by applications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
* (see mq_timedreceive() for the list list valid return values).
*
****************************************************************************/
ssize_t nxmq_timedreceive(mqd_t mqdes, FAR char *msg, size_t msglen,
FAR int *prio, FAR const struct timespec *abstime);
/****************************************************************************
* Name: nxmq_free_msgq
*
* Description:
* This function deallocates an initialized message queue structure.
* First, it deallocates all of the queued messages in the message
* queue. It is assumed that this message is fully unlinked and
* closed so that no thread will attempt access it while it is being
* deleted.
*
* Input Parameters:
* msgq - Named essage queue to be freed
*
* Returned Value:
* None
*
****************************************************************************/
void nxmq_free_msgq(FAR struct mqueue_inode_s *msgq);
/****************************************************************************
* Name: nxmq_alloc_msgq
*
* Description:
* This function implements a part of the POSIX message queue open logic.
* It allocates and initializes a structu mqueue_inode_s structure.
*
* Input Parameters:
* mode - mode_t value is ignored
* 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.
*
* Returned Value:
* The allocated and initalized message queue structure or NULL in the
* event of a failure.
*
****************************************************************************/
FAR struct mqueue_inode_s *nxmq_alloc_msgq(mode_t mode,
FAR struct mq_attr *attr);
/****************************************************************************
* Name: nxmq_create_des
*
* Description:
* Create a message queue descriptor for the specified TCB
*
* Input Parameters:
* TCB - task that needs the descriptor.
* msgq - Named message queue containing the message
* oflags - access rights for the descriptor
*
* Returned Value:
* On success, the message queue descriptor is returned. NULL is returned
* on a failure to allocate.
*
****************************************************************************/
mqd_t nxmq_create_des(FAR struct tcb_s *mtcb,
FAR struct mqueue_inode_s *msgq, int oflags);
/****************************************************************************
* Name: nxmq_close_group
*
* Description:
* This function is used to indicate that all threads in the group are
* finished with the specified message queue mqdes. nxmq_close_group()
* deallocates any system resources allocated by the system for use by
* this task for its message queue.
*
* Input Parameters:
* mqdes - Message queue descriptor.
* group - Group that has the open descriptor.
*
* Returned Value:
* Zero (OK) if the message queue is closed successfully. Otherwise, a
* negated errno value is returned.
*
****************************************************************************/
int nxmq_close_group(mqd_t mqdes, FAR struct task_group_s *group);
/****************************************************************************
* Name: nxmq_desclose_group
*
* Description:
* This function performs the portion of the mq_close operation related
* to freeing resource used by the message queue descriptor itself.
*
* Input Parameters:
* mqdes - Message queue descriptor.
* group - Group that has the open descriptor.
*
* Returned Value:
* None.
*
* Assumptions:
* - Called only from mq_close() with the scheduler locked.
*
****************************************************************************/
void nxmq_desclose_group(mqd_t mqdes, FAR struct task_group_s *group);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_MQ_MAXMSGSIZE > 0 */
#endif /* ___INCLUDE_NUTTX_MQUEUE_H */