107 lines
3.6 KiB
C
107 lines
3.6 KiB
C
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/************************************************************
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* fs_telldir.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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 Gregory Nutt 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 <dirent.h>
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#include <errno.h>
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#include <nuttx/fs.h>
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#include "fs_internal.h"
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/************************************************************
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* Private Functions
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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: telldir
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*
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* Description:
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* The telldir() function returns the current location
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* associated with the directory stream dirp.
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*
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* Inputs:
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* dirp -- An instance of type DIR created by a previous
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* call to opendir();
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*
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* Return:
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* On success, the telldir() function returns the current
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* location in the directory stream. On error, -1 is
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* returned, and errno is set appropriately.
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*
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* EBADF - Invalid directory stream descriptor dir
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*
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************************************************************/
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#if CONFIG_NFILE_DESCRIPTORS > 0
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off_t telldir(FAR DIR *dirp)
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{
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struct internal_dir_s *idir = (struct internal_dir_s *)dirp;
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struct inode *curr;
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off_t offs;
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if (!idir)
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{
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*get_errno_ptr() = EBADF;
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return -1;
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}
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/* Traverse the peer list starting at the 'root' of the
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* the list until we find the 'next' node. If devices
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* are being registered and unregistered, then this can
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* be a very unpredictable operation.
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*/
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inode_semtake();
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for (offs = 0, curr = idir->root;
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curr && curr != idir->next;
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offs++, curr = curr->i_peer);
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/* We should have an offset now corresponding to idir->next.*/
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inode_semgive();
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return offs;
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}
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#endif /* CONFIG_NFILE_DESCRIPTORS */
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