/************************************************************
* 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
************************************************************/
/************************************************************
* Name: fs_finddirnode
*
* Description:
* This is called from the opendir() logic to get a reference
* to the inode associated with a directory. There are no
* real directories in this design; For our purposes, a
* directory inode is simply one that has children or one
* that is a mountpoint for a "real" file system
*
************************************************************/
static inline FAR struct inode *fs_finddirnode(const char *path, const char **relpath)
{
FAR struct inode *node;
FAR struct inode *root = NULL;
/* If we are given 'nothing' then we will interpret this as
* request for the root inode.
*/
if (!path || *path == 0 || strcmp(path, "/") == 0)
{
return root_inode;
}
/* We don't know what to do with relative pathes */
if (*path != '/')
{
return NULL;
}
/* Find the node matching the path. */
inode_semtake();
node = inode_search(&path, (FAR void*)NULL, (FAR void*)NULL, relpath);
if (node)
{
/* Is this a not in the psuedo filesystem? */
if (INODE_IS_MOUNTPT(node))
{
/* Yes, then return the inode itself as the 'root' of
* the directory. The actually directory is at relpath into the
* mounted filesystem. Increment the count of references
* on the inode.
*/
root = node;
root->i_crefs++;
}
else
{
/* It is a node in the psuedo filesystem. Does the inode have a child?
* If so that the child would be the 'root' of a list of nodes under
* the directory.
*/
root = node->i_child;
if (root)
{
/* If found, then increment the count of
* references on the child node.
*/
root->i_crefs++;
}
}
}
inode_semgive();
return root;
}
/************************************************************
* 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;
const char *relpath;
int ret;
/* Get an inode corresponding to the path. On successful
* return, we will hold on reference count on the inode.
*/
inode = fs_finddirnode(path, &relpath);
if (!inode)
{
/* 'path' is not a directory.*/
ret = ENOTDIR;
goto errout;
}
/* 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_inode;
}
/* 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->root = inode; /* Save the inode where we start */
dir->position = 0; /* This is the position in the read stream */
/* Is this a not in the psuedo filesystem? */
if (INODE_IS_MOUNTPT(inode))
{
/* 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;
}
/* Perform the opendir() operation */
ret = inode->u.i_mops->opendir(inode, relpath, dir);
if (ret < 0)
{
ret = -ret;
goto errout_with_direntry;
}
}
else
{
/* The node is part of the root psuedo file system */
inode_addref(inode); /* Now we have two references on inode */
dir->u.psuedo.next = inode; /* This is the next node to use for readdir() */
}
return ((DIR*)dir);
/* Nasty goto's make error handling simpler */
errout_with_direntry:
free(dir);
errout_with_inode:
inode_release(inode);
errout:
*get_errno_ptr() = ret;
return NULL;
}
#endif /* CONFIG_NFILE_DESCRIPTORS */
