/************************************************************
* fs_readdir.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 <string.h>
#include <dirent.h>
#include <errno.h>
#include <nuttx/fs.h>
#include "fs_internal.h"
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Name: readpsuedodir
************************************************************/
#if CONFIG_NFILE_DESCRIPTORS > 0
static inline int readpsuedodir(struct internal_dir_s *idir)
{
FAR struct inode *prev;
/* Check if we are at the end of the list */
if (!idir->u.psuedo.fd_next)
{
/* End of file and error conditions are not distinguishable
* with readdir. Here we return -ENOENT to signal the end
* of the directory.
*/
return -ENOENT;
}
/* Copy the inode name into the dirent structure */
strncpy(idir->fd_dir.d_name, idir->u.psuedo.fd_next->i_name, NAME_MAX+1);
/* If the node has file operations, we will say that it is
* a file.
*/
idir->fd_dir.d_type = 0;
if (idir->u.psuedo.fd_next->u.i_ops)
{
idir->fd_dir.d_type |= DTYPE_FILE;
}
/* If the node has child node(s), then we will say that it
* is a directory. NOTE: that the node can be both!
*/
if (idir->u.psuedo.fd_next->i_child || !idir->u.psuedo.fd_next->u.i_ops)
{
idir->fd_dir.d_type |= DTYPE_DIRECTORY;
}
/* Now get the inode to vist next time that readdir() is called */
inode_semtake();
prev = idir->u.psuedo.fd_next;
idir->u.psuedo.fd_next = prev->i_peer; /* The next node to visit */
if (idir->u.psuedo.fd_next)
{
/* Increment the reference count on this next node */
idir->u.psuedo.fd_next->i_crefs++;
}
inode_semgive();
if (prev)
{
inode_release(prev);
}
return OK;
}
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Name: readdir
*
* Description:
* The readdir() function returns a pointer to a dirent
* structure representing the next directory entry in the
* directory stream pointed to by dir. It returns NULL on
* reaching the end-of-file or if an error occurred.
*
* Inputs:
* dirp -- An instance of type DIR created by a previous
* call to opendir();
*
* Return:
* The readdir() function returns a pointer to a dirent
* structure, or NULL if an error occurs or end-of-file
* is reached. On error, errno is set appropriately.
*
* EBADF - Invalid directory stream descriptor dir
*
************************************************************/
FAR struct dirent *readdir(DIR *dirp)
{
FAR struct internal_dir_s *idir = (struct internal_dir_s *)dirp;
struct inode *inode;
int ret;
/* Sanity checks */
if (!idir || !idir->fd_root)
{
ret = EBADF;
goto errout;
}
/* The way we handle the readdir depends on the type of inode
* that we are dealing with.
*/
inode = idir->fd_root;
if (INODE_IS_MOUNTPT(inode))
{
/* The node is a file system mointpoint. Verify that the mountpoint
* supports the readdir() method
*/
if (!inode->u.i_mops || !inode->u.i_mops->readdir)
{
ret = EACCES;
goto errout;
}
/* Perform the readdir() operation */
ret = inode->u.i_mops->readdir(inode, idir);
}
else
{
/* The node is part of the root psuedo file system, release
* our contained reference to the 'next' inode.
*/
ret = readpsuedodir(idir);
}
/* ret < 0 is an error. Special case: ret = -ENOENT is end of file */
if ( ret < 0)
{
if (ret == -ENOENT)
{
ret = OK;
}
else
{
ret = -ret;
}
goto errout;
}
/* Success */
idir->fd_position++;
return &idir->fd_dir;
errout:
*get_errno_ptr() = ret;
return NULL;
}
#endif /* CONFIG_NFILE_DESCRIPTORS */
