void mq_inode_release(FAR struct inode *inode)
{
/* Decrement the reference count on the inode */
inode_semtake();
if (inode->i_crefs > 0)
{
inode->i_crefs--;
}
/* If the message queue was previously unlinked and the reference count
* has decremented to zero, then release the message queue and delete
* the inode now.
*/
if (inode->i_crefs <= 0 && (inode->i_flags & FSNODEFLAG_DELETED) != 0)
{
FAR struct mqueue_inode_s *msgq = inode->u.i_mqueue;
DEBUGASSERT(msgq);
/* Free the message queue (and any messages left in it) */
mq_msgqfree(msgq);
inode->u.i_mqueue = NULL;
/* Release and free the inode container */
inode_semgive();
inode_free(inode->i_child);
kmm_free(inode);
return;
}
inode_semgive();
}
mqd_t mq_open(FAR const char *mq_name, int oflags, ...)
{
FAR struct inode *inode;
FAR const char *relpath = NULL;
FAR struct mqueue_inode_s *msgq;
char fullpath[MAX_MQUEUE_PATH];
va_list ap;
struct mq_attr *attr;
mqd_t mqdes;
mode_t mode;
int errcode;
int ret;
/* Make sure that a non-NULL name is supplied */
if (!mq_name)
{
errcode = EINVAL;
goto errout;
}
/* Get the full path to the message queue */
snprintf(fullpath, MAX_MQUEUE_PATH, CONFIG_FS_MQUEUE_MPATH "/%s", mq_name);
/* Make sure that the check for the existence of the message queue
* and the creation of the message queue are atomic with respect to
* other processes executing mq_open(). A simple sched_lock() should
* be sufficient.
*/
sched_lock();
/* Get the inode for this mqueue. This should succeed if the message
* queue has already been created.
*/
inode = inode_find(fullpath, &relpath);
if (inode)
{
/* It exists. Verify that the inode is a message queue */
if (!INODE_IS_MQUEUE(inode))
{
errcode = ENXIO;
goto errout_with_inode;
}
/* It exists and is a message queue. Check if the caller wanted to
* create a new mqueue with this name.
*/
if ((oflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
{
errcode = EEXIST;
goto errout_with_inode;
}
/* Create a message queue descriptor for the current thread */
msgq = inode->u.i_mqueue;
mqdes = mq_descreate(NULL, msgq, oflags);
if (!mqdes)
{
errcode = ENOMEM;
goto errout_with_inode;
}
}
else
{
/* The mqueue does not exists. Were we asked to create it? */
if ((oflags & O_CREAT) == 0)
{
/* The mqueue does not exist and O_CREAT is not set */
errcode = ENOENT;
goto errout_with_lock;
}
/* Create the mqueue. First we have to extract the additional
* parameters from the variable argument list.
*/
va_start(ap, oflags);
mode = va_arg(ap, mode_t);
attr = va_arg(ap, FAR struct mq_attr*);
va_end(ap);
/* Create an inode in the pseudo-filesystem at this path */
inode_semtake();
ret = inode_reserve(fullpath, &inode);
inode_semgive();
if (ret < 0)
{
errcode = -ret;
goto errout_with_lock;
}
/* Allocate memory for the new message queue. */
msgq = (FAR struct mqueue_inode_s*)mq_msgqalloc(mode, attr);
if (!msgq)
{
errcode = ENOSPC;
goto errout_with_inode;
}
/* Create a message queue descriptor for the TCB */
mqdes = mq_descreate(NULL, msgq, oflags);
if (!mqdes)
{
errcode = ENOMEM;
goto errout_with_msgq;
}
/* Bind the message queue and the inode structure */
INODE_SET_MQUEUE(inode);
inode->u.i_mqueue = msgq;
msgq->inode = inode;
}
sched_unlock();
return mqdes;
errout_with_msgq:
mq_msgqfree(msgq);
inode->u.i_mqueue = NULL;
errout_with_inode:
inode_release(inode);
errout_with_lock:
sched_unlock();
errout:
set_errno(errcode);
return (mqd_t)ERROR;
}
int mq_close(mqd_t mqdes)
{
FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head;
FAR msgq_t *msgq;
irqstate_t saved_state;
int ret = ERROR;
/* Verify the inputs */
if (mqdes)
{
sched_lock();
/* Remove the message descriptor from the current task's
* list of message descriptors.
*/
sq_rem((FAR sq_entry_t*)mqdes, &rtcb->msgdesq);
/* Find the message queue associated with the message descriptor */
msgq = mqdes->msgq;
/* Check if the calling task has a notification attached to
* the message queue via this mqdes.
*/
#ifndef CONFIG_DISABLE_SIGNALS
if (msgq->ntmqdes == mqdes)
{
msgq->ntpid = INVALID_PROCESS_ID;
msgq->ntsigno = 0;
msgq->ntvalue.sival_int = 0;
msgq->ntmqdes = NULL;
}
#endif
/* Decrement the connection count on the message queue. */
if (msgq->nconnect)
{
msgq->nconnect--;
}
/* If it is no longer connected to any message descriptor and if the
* message queue has already been unlinked, then we can discard the
* message queue.
*/
if (!msgq->nconnect && msgq->unlinked)
{
/* Remove the message queue from the list of all
* message queues
*/
saved_state = irqsave();
(void)sq_rem((FAR sq_entry_t*)msgq, &g_msgqueues);
irqrestore(saved_state);
/* Then deallocate it (and any messages left in it) */
mq_msgqfree(msgq);
}
/* Deallocate the message descriptor */
mq_desfree(mqdes);
sched_unlock();
ret = OK;
}
return ret;
}
