nuttx/fs/inode/fs_filedetach.c
Gregory Nutt a4d6af8343 Check return from nxsem_wait_initialize()
Resolution of Issue 619 will require multiple steps, this part of the first step in that resolution:  Every call to nxsem_wait_uninterruptible() must handle the return value from nxsem_wait_uninterruptible properly.  This commit is only for those files under fs/inode.  Utility functions under fs/incode were modified so the changes do extend to other fs/ sub-directories as well.
2020-03-30 01:33:31 +01:00

148 lines
4.5 KiB
C

/****************************************************************************
* fs/inode/fs_filedetach.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 <assert.h>
#include <errno.h>
#include <nuttx/sched.h>
#include <nuttx/fs/fs.h>
#include <nuttx/semaphore.h>
#include "inode/inode.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: _files_semtake
****************************************************************************/
static inline int _files_semtake(FAR struct filelist *list)
{
return nxsem_wait_uninterruptible(&list->fl_sem);
}
/****************************************************************************
* Name: _files_semgive
****************************************************************************/
#define _files_semgive(list) nxsem_post(&list->fl_sem)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: file_detach
*
* Description:
* This function is used in device drivers to create a task-independent
* handle to an entity in the file system. file_detach() duplicates the
* 'struct file' that underlies the file descriptor, then closes the file
* descriptor.
*
* This function will fail if fd is not a valid file descriptor. In
* particular, it will fail if fd is a socket descriptor.
*
* Input Parameters:
* fd - The file descriptor to be detached. This descriptor will be
* closed and invalid if the file was successfully detached.
* filep - A pointer to a user provided memory location in which to
* received the duplicated, detached file structure.
*
* Returned Value:
* Zero (OK) is returned on success; A negated errno value is returned on
* any failure to indicate the nature of the failure.
*
****************************************************************************/
int file_detach(int fd, FAR struct file *filep)
{
FAR struct filelist *list;
FAR struct file *parent;
int ret;
DEBUGASSERT(filep != NULL);
/* Verify the file descriptor range */
if (fd < 0 || fd >= CONFIG_NFILE_DESCRIPTORS)
{
/* Not a file descriptor (might be a socket descriptor) */
return -EBADF;
}
/* Get the thread-specific file list. It should never be NULL in this
* context.
*/
list = sched_getfiles();
DEBUGASSERT(list != NULL);
/* If the file was properly opened, there should be an inode assigned */
ret = _files_semtake(list);
if (ret < 0)
{
/* Probably canceled */
return ret;
}
parent = &list->fl_files[fd];
if (parent->f_inode == NULL)
{
/* File is not open */
_files_semgive(list);
return -EBADF;
}
/* Duplicate the 'struct file' content into the user-provided file
* structure.
*/
filep->f_oflags = parent->f_oflags;
filep->f_pos = parent->f_pos;
filep->f_inode = parent->f_inode;
filep->f_priv = parent->f_priv;
/* Release the file descriptor *without* calling the driver close method
* and without decrementing the inode reference count. That will be done
* in file_close().
*/
parent->f_oflags = 0;
parent->f_pos = 0;
parent->f_inode = NULL;
parent->f_priv = NULL;
_files_semgive(list);
return OK;
}