incubator-nuttx/fs/fs_opendir.c

127 lines
4.3 KiB
C

/************************************************************
* fs_opendir.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 <stdlib.h>
#include <dirent.h>
#include <errno.h>
#include <nuttx/fs.h>
#include "fs_internal.h"
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Name: opendir
*
* Description:
* The opendir() function opens a directory stream
* corresponding to the directory name, and returns a
* pointer to the directory stream. The stream is
* positioned at the first entry in the directory.
*
* Inputs:
* path -- the directory to open
*
* Return:
* The opendir() function returns a pointer to the
* directory stream. On error, NULL is returned, and
* errno is set appropriately.
*
* EACCES - Permission denied.
* EMFILE - Too many file descriptors in use by process.
* ENFILE - Too many files are currently open in the
* system.
* ENOENT - Directory does not exist, or name is an empty
* string.
* ENOMEM - Insufficient memory to complete the operation.
* ENOTDIR - 'path' is not a directory.
*
************************************************************/
#if CONFIG_NFILE_DESCRIPTORS > 0
FAR DIR *opendir(const char *path)
{
FAR struct inode *inode;
FAR struct internal_dir_s *dir;
/* Get an inode corresponding to the path. On successful
* return, we will hold on reference count on the inode.
*/
inode = inode_finddir(path);
if (!inode)
{
/* 'path' is not a directory.*/
*get_errno_ptr() = ENOTDIR;
return NULL;
}
/* Allocate a type DIR -- which is little more than an inode
* container.
*/
dir = (FAR struct internal_dir_s *)zalloc(sizeof(struct internal_dir_s));
if (!dir)
{
/* Insufficient memory to complete the operation.*/
*get_errno_ptr() = ENOMEM;
inode_release(inode);
return NULL;
}
/* Populate the DIR structure and return it to the caller */
dir->root = inode; /* Save where we started in case we rewind */
inode_addref(inode); /* Now we have two references on inode */
dir->next = inode; /* This is the next node to use for readdir() */
return ((DIR*)dir);
}
#endif /* CONFIG_NFILE_DESCRIPTORS */