408 lines
11 KiB
C
408 lines
11 KiB
C
/****************************************************************************
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* fs/fs_files.c
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*
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* Copyright (C) 2007-2009, 2011-2013 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <string.h>
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#include <semaphore.h>
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#include <assert.h>
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#include <sched.h>
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#include <errno.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/kmalloc.h>
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#include "fs_internal.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: _files_semtake
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****************************************************************************/
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static void _files_semtake(FAR struct filelist *list)
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{
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/* Take the semaphore (perhaps waiting) */
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while (sem_wait(&list->fl_sem) != 0)
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{
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/* The only case that an error should occr here is if
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* the wait was awakened by a signal.
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*/
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ASSERT(get_errno() == EINTR);
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}
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}
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/****************************************************************************
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* Name: _files_semgive
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****************************************************************************/
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#define _files_semgive(list) sem_post(&list->fl_sem)
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/****************************************************************************
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* Name: _files_close
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*
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* Description:
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* Close an inode (if open)
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*
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* Assumuptions:
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* Caller holds the list semaphore because the file descriptor will be freed.
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*
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****************************************************************************/
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static int _files_close(FAR struct file *filep)
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{
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struct inode *inode = filep->f_inode;
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int ret = OK;
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/* Check if the struct file is open (i.e., assigned an inode) */
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if (inode)
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{
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/* Close the file, driver, or mountpoint. */
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if (inode->u.i_ops && inode->u.i_ops->close)
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{
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/* Perform the close operation */
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ret = inode->u.i_ops->close(filep);
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}
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/* And release the inode */
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inode_release(inode);
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/* Release the file descriptor */
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filep->f_oflags = 0;
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filep->f_pos = 0;
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filep->f_inode = NULL;
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: files_initialize
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*
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* Description:
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* This is called from the FS initialization logic to configure the files.
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*
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****************************************************************************/
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void files_initialize(void)
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{
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}
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/****************************************************************************
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* Name: files_initlist
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*
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* Description: Initializes the list of files for a new task
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*
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****************************************************************************/
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void files_initlist(FAR struct filelist *list)
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{
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DEBUGASSERT(list);
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/* Initialize the list access mutex */
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(void)sem_init(&list->fl_sem, 0, 1);
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}
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/****************************************************************************
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* Name: files_releaselist
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*
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* Description:
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* Release a reference to the file list
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*
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****************************************************************************/
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void files_releaselist(FAR struct filelist *list)
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{
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int i;
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DEBUGASSERT(list);
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/* Close each file descriptor .. Normally, you would need take the list
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* semaphore, but it is safe to ignore the semaphore in this context because
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* there should not be any references in this context.
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*/
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for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
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{
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(void)_files_close(&list->fl_files[i]);
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}
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/* Destroy the semaphore */
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(void)sem_destroy(&list->fl_sem);
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}
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/****************************************************************************
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* Name: files_dup
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*
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* Description:
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* Assign an inode to a specific files structure. This is the heart of
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* dup2.
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*
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****************************************************************************/
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int files_dup(FAR struct file *filep1, FAR struct file *filep2)
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{
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FAR struct filelist *list;
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FAR struct inode *inode;
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int err;
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int ret;
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if (!filep1 || !filep1->f_inode || !filep2)
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{
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err = EBADF;
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goto errout;
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}
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list = sched_getfiles();
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if (!list)
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{
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err = EMFILE;
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goto errout;
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}
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_files_semtake(list);
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/* If there is already an inode contained in the new file structure,
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* close the file and release the inode.
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*/
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ret = _files_close(filep2);
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if (ret < 0)
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{
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/* An error occurred while closing the driver */
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goto errout_with_ret;
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}
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/* Increment the reference count on the contained inode */
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inode = filep1->f_inode;
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inode_addref(inode);
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/* Then clone the file structure */
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filep2->f_oflags = filep1->f_oflags;
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filep2->f_pos = filep1->f_pos;
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filep2->f_inode = inode;
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/* Call the open method on the file, driver, mountpoint so that it
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* can maintain the correct open counts.
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*/
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if (inode->u.i_ops && inode->u.i_ops->open)
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{
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#ifndef CONFIG_DISABLE_MOUNTPOINT
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if (INODE_IS_MOUNTPT(inode))
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{
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/* Dup the open file on the in the new file structure */
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ret = inode->u.i_mops->dup(filep1, filep2);
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}
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else
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#endif
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{
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/* (Re-)open the pseudo file or device driver */
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ret = inode->u.i_ops->open(filep2);
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}
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/* Handle open failures */
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if (ret < 0)
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{
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goto errout_with_inode;
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}
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}
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_files_semgive(list);
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return OK;
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/* Handler various error conditions */
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errout_with_inode:
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inode_release(filep2->f_inode);
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filep2->f_oflags = 0;
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filep2->f_pos = 0;
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filep2->f_inode = NULL;
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errout_with_ret:
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err = -ret;
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_files_semgive(list);
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errout:
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set_errno(err);
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return ERROR;
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}
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/****************************************************************************
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* Name: files_allocate
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*
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* Description:
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* Allocate a struct files instance and associate it with an inode instance.
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* Returns the file descriptor == index into the files array.
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*
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****************************************************************************/
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int files_allocate(FAR struct inode *inode, int oflags, off_t pos, int minfd)
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{
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FAR struct filelist *list;
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int i;
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list = sched_getfiles();
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if (list)
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{
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_files_semtake(list);
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for (i = minfd; i < CONFIG_NFILE_DESCRIPTORS; i++)
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{
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if (!list->fl_files[i].f_inode)
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{
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list->fl_files[i].f_oflags = oflags;
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list->fl_files[i].f_pos = pos;
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list->fl_files[i].f_inode = inode;
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list->fl_files[i].f_priv = NULL;
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_files_semgive(list);
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return i;
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}
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}
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_files_semgive(list);
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}
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return ERROR;
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}
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/****************************************************************************
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* Name: files_close
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*
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* Description:
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* Close an inode (if open)
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*
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* Assumuptions:
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* Caller holds the list semaphore because the file descriptor will be freed.
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*
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****************************************************************************/
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int files_close(int filedes)
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{
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FAR struct filelist *list;
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int ret;
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/* Get the thread-specific file list */
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list = sched_getfiles();
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if (!list)
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{
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return -EMFILE;
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}
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/* If the file was properly opened, there should be an inode assigned */
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if (filedes < 0 || filedes >= CONFIG_NFILE_DESCRIPTORS || !list->fl_files[filedes].f_inode)
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{
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return -EBADF;
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}
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/* Perform the protected close operation */
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_files_semtake(list);
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ret = _files_close(&list->fl_files[filedes]);
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_files_semgive(list);
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return ret;
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}
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/****************************************************************************
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* Name: files_release
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*
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* Assumuptions:
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* Similar to files_close(). Called only from open() logic on error
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* conditions.
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*
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****************************************************************************/
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void files_release(int filedes)
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{
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FAR struct filelist *list;
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list = sched_getfiles();
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if (list)
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{
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if (filedes >=0 && filedes < CONFIG_NFILE_DESCRIPTORS)
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{
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_files_semtake(list);
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list->fl_files[filedes].f_oflags = 0;
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list->fl_files[filedes].f_pos = 0;
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list->fl_files[filedes].f_inode = NULL;
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_files_semgive(list);
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}
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}
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}
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