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- /****************************************************************************
- * fs/inode/fs_filedetach.c
- *
- * Copyright (C) 2016 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.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <semaphore.h>
- #include <assert.h>
- #include <errno.h>
- #include <nuttx/sched.h>
- #include <nuttx/fs/fs.h>
- #include "inode/inode.h"
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: _files_semtake
- ****************************************************************************/
- static inline void _files_semtake(FAR struct filelist *list)
- {
- /* Take the semaphore (perhaps waiting) */
- while (sem_wait(&list->fl_sem) != 0)
- {
- /* The only case that an error should occur here is if
- * the wait was awakened by a signal.
- */
- DEBUGASSERT(get_errno() == EINTR);
- }
- }
- /****************************************************************************
- * Name: _files_semgive
- ****************************************************************************/
- #define _files_semgive(list) sem_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.
- *
- ****************************************************************************/
- #if CONFIG_NFILE_DESCRIPTORS > 0
- int file_detach(int fd, FAR struct file *filep)
- {
- FAR struct filelist *list;
- FAR struct file *parent;
- /* 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 */
- _files_semtake(list);
- 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 descriptore *without* calling the drive close method
- * and without decrementing the inode reference count. That will be done
- * in file_close_detached().
- */
- parent->f_oflags = 0;
- parent->f_pos = 0;
- parent->f_inode = NULL;
- parent->f_priv = NULL;
- _files_semgive(list);
- return OK;
- }
- #endif
- /****************************************************************************
- * Name: file_close_detached
- *
- * Description:
- * Close a file that was previously detached with file_detach().
- *
- * REVISIT: This is essentially the same as _files_close()
- *
- * Input Parameters:
- * filep - A pointer to a user provided memory location containing the
- * open file data returned by file_detach().
- *
- * 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_close_detached(FAR struct file *filep)
- {
- struct inode *inode;
- int ret = OK;
- DEBUGASSERT(filep != NULL);
- inode = filep->f_inode;
- /* Check if the struct file is open (i.e., assigned an inode) */
- if (inode)
- {
- /* Close the file, driver, or mountpoint. */
- if (inode->u.i_ops && inode->u.i_ops->close)
- {
- /* Perform the close operation */
- ret = inode->u.i_ops->close(filep);
- }
- /* And release the inode */
- inode_release(inode);
- /* Reset the user file struct instance so that it cannot be reused. */
- filep->f_oflags = 0;
- filep->f_pos = 0;
- filep->f_inode = NULL;
- filep->f_priv = NULL;
- }
- return ret;
- }
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