int inode_stat(FAR struct inode *inode, FAR struct stat *buf)
{
DEBUGASSERT(inode != NULL && buf != NULL);
memset(buf, 0, sizeof(*buf));
if (INODE_IS_SPECIAL(inode)) {
#if defined(CONFIG_FS_NAMED_SEMAPHORES)
if (INODE_IS_NAMEDSEM(inode)) {
buf->st_mode = S_IFSEM;
} else
#endif
#if !defined(CONFIG_DISABLE_MQUEUE)
if (INODE_IS_MQUEUE(inode)) {
buf->st_mode = S_IFMQ;
} else
#endif
{
}
} else if (inode->u.i_ops != NULL) {
/* Determine read/write privileges based on the existence of read
* and write methods.
*/
if (inode->u.i_ops->read) {
buf->st_mode = S_IROTH | S_IRGRP | S_IRUSR;
}
if (inode->u.i_ops->write) {
buf->st_mode |= S_IWOTH | S_IWGRP | S_IWUSR;
}
/* Determine the type of the inode */
if (INODE_IS_MOUNTPT(inode)) {
buf->st_mode |= S_IFDIR;
} else if (INODE_IS_BLOCK(inode)) {
/* What is if also has child inodes? */
buf->st_mode |= S_IFBLK;
} else /* if (INODE_IS_DRIVER(inode)) */ {
/* What is it if it also has child inodes? */
buf->st_mode |= S_IFCHR;
}
} else {
/* If it has no operations, then it must just be a intermediate
* node in the inode tree. It is something like a directory.
* We'll say that all pseudo-directories are read-able but not
* write-able.
*/
buf->st_mode |= S_IFDIR | S_IROTH | S_IRGRP | S_IRUSR;
}
return OK;
}
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_unlink(FAR const char *mq_name)
{
FAR struct inode *inode;
FAR const char *relpath = NULL;
char fullpath[MAX_MQUEUE_PATH];
int errcode;
int ret;
/* Get the full path to the message queue */
snprintf(fullpath, MAX_MQUEUE_PATH, CONFIG_FS_MQUEUE_MPATH "/%s", mq_name);
/* Get the inode for this message queue. */
sched_lock();
inode = inode_find(fullpath, &relpath);
if (!inode)
{
/* There is no inode that includes in this path */
errcode = ENOENT;
goto errout;
}
/* Verify that what we found is, indeed, a message queue */
if (!INODE_IS_MQUEUE(inode))
{
errcode = ENXIO;
goto errout_with_inode;
}
/* Refuse to unlink the inode if it has children. I.e., if it is
* functioning as a directory and the directory is not empty.
*/
inode_semtake();
if (inode->i_child != NULL)
{
errcode = ENOTEMPTY;
goto errout_with_semaphore;
}
/* Remove the old inode from the tree. Because we hold a reference count
* on the inode, it will not be deleted now. This will set the
* FSNODEFLAG_DELETED bit in the inode flags.
*/
ret = inode_remove(fullpath);
/* inode_remove() should always fail with -EBUSY because we hae a reference
* on the inode. -EBUSY means taht the inode was, indeed, unlinked but
* thatis could not be freed because there are refrences.
*/
DEBUGASSERT(ret >= 0 || ret == -EBUSY);
UNUSED(ret);
/* Now we do not release the reference count in the normal way (by calling
* inode release. Rather, we call mq_inode_release(). mq_inode_release
* will decrement the reference count on the inode. But it will also free
* the message queue if that reference count decrements to zero. Since we
* hold one reference, that can only occur if the message queue is not
* in-use.
*/
inode_semgive();
mq_inode_release(inode);
sched_unlock();
return OK;
errout_with_semaphore:
inode_semgive();
errout_with_inode:
inode_release(inode);
errout:
set_errno(errcode);
sched_unlock();
return ERROR;
}
