157 lines
4.5 KiB
C
157 lines
4.5 KiB
C
/****************************************************************************
|
|
* fs/semaphore/sem_unlink.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <stdbool.h>
|
|
#include <stdio.h>
|
|
#include <sched.h>
|
|
#include <errno.h>
|
|
#include <assert.h>
|
|
|
|
#include <nuttx/kmalloc.h>
|
|
#include <nuttx/semaphore.h>
|
|
|
|
#include "inode/inode.h"
|
|
#include "notify/notify.h"
|
|
#include "semaphore/semaphore.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: nxsem_unlink
|
|
*
|
|
* Description:
|
|
* This function removes the semaphore named by the input parameter 'name.'
|
|
* If the semaphore named by 'name' is currently referenced by other task,
|
|
* the sem_unlink() will have no effect on the state of the semaphore. If
|
|
* one or more processes have the semaphore open when sem_unlink() is
|
|
* called, destruction of the semaphore will be postponed until all
|
|
* references to the semaphore have been destroyed by calls of sem_close().
|
|
*
|
|
* Input Parameters:
|
|
* name - Semaphore name
|
|
*
|
|
* Returned Value:
|
|
* 0 (OK), or negated errno if unsuccessful.
|
|
*
|
|
* Assumptions:
|
|
*
|
|
****************************************************************************/
|
|
|
|
int nxsem_unlink(FAR const char *name)
|
|
{
|
|
FAR struct inode *inode;
|
|
struct inode_search_s desc;
|
|
char fullpath[MAX_SEMPATH];
|
|
int ret;
|
|
|
|
/* Get the full path to the semaphore */
|
|
|
|
snprintf(fullpath, MAX_SEMPATH,
|
|
CONFIG_FS_NAMED_SEMAPHORES_VFS_PATH "/%s", name);
|
|
|
|
/* Get the inode for this semaphore. */
|
|
|
|
SETUP_SEARCH(&desc, fullpath, false);
|
|
|
|
ret = inode_find(&desc);
|
|
if (ret < 0)
|
|
{
|
|
/* There is no inode that includes in this path */
|
|
|
|
goto errout_with_search;
|
|
}
|
|
|
|
/* Get the search results */
|
|
|
|
inode = desc.node;
|
|
|
|
/* Verify that what we found is, indeed, a semaphore */
|
|
|
|
if (!INODE_IS_NAMEDSEM(inode))
|
|
{
|
|
ret = -ENOENT;
|
|
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.
|
|
*/
|
|
|
|
ret = inode_lock();
|
|
if (ret < 0)
|
|
{
|
|
goto errout_with_inode;
|
|
}
|
|
|
|
if (inode->i_child != NULL)
|
|
{
|
|
ret = -ENOTEMPTY;
|
|
goto errout_with_lock;
|
|
}
|
|
|
|
/* Remove the old inode from the tree. Because we hold a reference count
|
|
* on the inode, it will not be deleted now. This will put reference of
|
|
* inode.
|
|
*/
|
|
|
|
ret = inode_remove(fullpath);
|
|
|
|
/* inode_remove() should always fail with -EBUSY because we hae a reference
|
|
* on the inode. -EBUSY means that the inode was, indeed, unlinked but
|
|
* thatis could not be freed because there are references.
|
|
*/
|
|
|
|
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 sem_close(). sem_close will decrement
|
|
* the reference count on the inode. But it will also free the semaphore
|
|
* if that reference count decrements to zero. Since we hold one
|
|
* reference, that can only occur if the semaphore is not in-use.
|
|
*/
|
|
|
|
inode_unlock();
|
|
ret = nxsem_close(&inode->u.i_nsem->ns_sem);
|
|
RELEASE_SEARCH(&desc);
|
|
#ifdef CONFIG_FS_NOTIFY
|
|
notify_unlink(fullpath);
|
|
#endif
|
|
return ret;
|
|
|
|
errout_with_lock:
|
|
inode_unlock();
|
|
|
|
errout_with_inode:
|
|
inode_release(inode);
|
|
|
|
errout_with_search:
|
|
RELEASE_SEARCH(&desc);
|
|
return ret;
|
|
}
|