/************************************************************
* 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 <string.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.
*
************************************************************/
FAR DIR *opendir(const char *path)
{
FAR struct inode *inode = NULL;
FAR struct internal_dir_s *dir;
const char *relpath;
boolean isroot = FALSE;
int ret;
/* If we are given 'nothing' then we will interpret this as
* request for the root inode.
*/
if (!path || *path == 0 || strcmp(path, "/") == 0)
{
inode_semgive();
inode = root_inode;
isroot = TRUE;
}
else
{
/* We don't know what to do with relative pathes */
if (*path != '/')
{
return NULL;
}
/* Find the node matching the path. */
inode_semtake();
inode = inode_search(&path, (FAR void*)NULL, (FAR void*)NULL, &relpath);
}
/* Did we get an inode? */
if (!inode)
{
/* 'path' is not a does not exist.*/
ret = ENOTDIR;
goto errout_with_semaphore;
}
/* 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.*/
ret = ENOMEM;
goto errout_with_semaphore;
}
/* Populate the DIR structure and return it to the caller. The way that
* we do this depends on whenever this is a "normal" psuedo-file-system
* inode or a file system mountpoint.
*/
dir->fd_root = inode; /* Save the inode where we start */
dir->fd_position = 0; /* This is the position in the read stream */
/* Is this a node in the psuedo filesystem? Or a mountpoint? */
#ifndef CONFIG_DISABLE_MOUNTPOINT
if (INODE_IS_MOUNTPT(inode))
{
/* Yes, then return the inode itself as the 'root' of
* the directory. The actually directory is at relpath into the
* mounted filesystem.
*/
/* The node is a file system mointpoint. Verify that the mountpoint
* supports the opendir() method
*/
if (!inode->u.i_mops || !inode->u.i_mops->opendir)
{
ret = ENOSYS;
goto errout_with_direntry;
}
/* Take reference to the mountpoint inode (fd_root) */
inode_addref(inode);
/* Perform the opendir() operation */
ret = inode->u.i_mops->opendir(inode, relpath, dir);
if (ret < 0)
{
ret = -ret;
goto errout_with_inode;
}
}
else
#endif
{
/* The node is part of the root psuedo file system. Does the inode have a child?
* If so that the child would be the 'root' of a list of nodes under
* the directory.
*/
if (!isroot)
{
inode = inode->i_child;
if (!inode)
{
ret = ENOTDIR;
goto errout_with_direntry;
}
}
/* It looks we have a valid psuedo-filesystem node. Take two references
* on the inode -- one for the parent (fd_root) and one for the child (fd_next).
*/
inode_addref(inode);
inode_addref(inode);
dir->u.psuedo.fd_next = inode; /* This is the next node to use for readdir() */
/* Flag the inode as belonging to the psuedo-filesystem */
#ifndef CONFIG_DISABLE_MOUNTPOINT
DIRENT_SETPSUEDONODE(dir->fd_flags);
#endif
}
inode_semgive();
return ((DIR*)dir);
/* Nasty goto's make error handling simpler */
errout_with_inode:
inode_release(inode);
errout_with_direntry:
free(dir);
errout_with_semaphore:
inode_semgive();
*get_errno_ptr() = ret;
return NULL;
}
