599f8b4682
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@62 42af7a65-404d-4744-a932-0658087f49c3
118 lines
3.8 KiB
C
118 lines
3.8 KiB
C
/************************************************************
|
|
* fs_seekdir.c
|
|
*
|
|
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
|
|
*
|
|
* 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 Gregory Nutt 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 <sys/types.h>
|
|
#include <dirent.h>
|
|
#include <errno.h>
|
|
#include <nuttx/fs.h>
|
|
#include "fs_internal.h"
|
|
|
|
/************************************************************
|
|
* Private Functions
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Public Functions
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Name: seekdir
|
|
*
|
|
* Description:
|
|
* The seekdir() function sets the location in the
|
|
* directory stream from which the next readdir() call will
|
|
* start. seekdir() should be used with an offset returned
|
|
* by telldir().
|
|
*
|
|
* Inputs:
|
|
* dirp -- An instance of type DIR created by a previous
|
|
* call to opendir();
|
|
* offset -- offset to seek to
|
|
*
|
|
* Return:
|
|
* None
|
|
*
|
|
************************************************************/
|
|
|
|
#if CONFIG_NFILE_DESCRIPTORS > 0
|
|
|
|
void seekdir(FAR DIR *dirp, off_t offset)
|
|
{
|
|
struct internal_dir_s *idir = (struct internal_dir_s *)dirp;
|
|
struct inode *curr;
|
|
struct inode *prev;
|
|
off_t i;
|
|
|
|
if (idir)
|
|
{
|
|
/* Traverse the peer list starting at the 'root' of the
|
|
* the list until we find the node at 'offset". If devices
|
|
* are being registered and unregistered, then this can
|
|
* be a very unpredictable operation.
|
|
*/
|
|
|
|
inode_semtake();
|
|
for (i = 0, curr = idir->root;
|
|
curr && i != offset;
|
|
i++, curr = curr->i_peer);
|
|
|
|
/* Now get the inode to vist next time that readdir() is called */
|
|
|
|
prev = idir->next;
|
|
idir->next = curr; /* The next node to visit */
|
|
|
|
if (curr)
|
|
{
|
|
/* Increment the reference count on this next node */
|
|
|
|
curr->i_crefs++;
|
|
}
|
|
|
|
inode_semgive();
|
|
|
|
if (prev)
|
|
{
|
|
inode_release(prev);
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif /* CONFIG_NFILE_DESCRIPTORS */
|