/****************************************************************************
* fs/dirent/fs_readdir.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include <dirent.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/dirent.h>
#include "inode/inode.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: readpseudodir
****************************************************************************/
static inline int readpseudodir(struct fs_dirent_s *idir)
{
FAR struct inode *prev;
int ret;
/* Check if we are at the end of the list */
if (!idir->u.pseudo.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 */
strlcpy(idir->fd_dir.d_name, idir->u.pseudo.fd_next->i_name,
sizeof(idir->fd_dir.d_name));
/* If the node has file operations, we will say that it is a file. */
idir->fd_dir.d_type = DTYPE_UNKNOWN;
if (idir->u.pseudo.fd_next->u.i_ops)
{
#ifndef CONFIG_DISABLE_MOUNTPOINT
if (INODE_IS_BLOCK(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_BLK;
}
else if (INODE_IS_MTD(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_MTD;
}
else if (INODE_IS_MOUNTPT(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_DIRECTORY;
}
else
#endif
#ifdef CONFIG_PSEUDOFS_SOFTLINKS
if (INODE_IS_SOFTLINK(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_LINK;
}
else
#endif
if (INODE_IS_DRIVER(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_CHR;
}
else if (INODE_IS_NAMEDSEM(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_SEM;
}
else if (INODE_IS_MQUEUE(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_MQ;
}
else if (INODE_IS_SHM(idir->u.pseudo.fd_next))
{
idir->fd_dir.d_type = DTYPE_SHM;
}
}
/* If the node has child node(s) or no operations, then we will say that
* it is a directory rather than a special file. NOTE: that the node can
* be both!
*/
if (idir->u.pseudo.fd_next->i_child || !idir->u.pseudo.fd_next->u.i_ops)
{
idir->fd_dir.d_type = DTYPE_DIRECTORY;
}
/* Now get the inode to visit next time that readdir() is called */
ret = inode_semtake();
if (ret < 0)
{
return ret;
}
prev = idir->u.pseudo.fd_next;
idir->u.pseudo.fd_next = prev->i_peer; /* The next node to visit */
if (idir->u.pseudo.fd_next)
{
/* Increment the reference count on this next node */
idir->u.pseudo.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.
*
* Input Parameters:
* dirp -- An instance of type DIR created by a previous call to opendir();
*
* Returned Value:
* 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 fs_dirent_s *idir = (struct fs_dirent_s *)dirp;
struct inode *inode;
int ret;
/* Verify that we were provided with a valid directory structure */
if (!idir)
{
ret = -EBADF;
goto errout;
}
/* A special case is when we enumerate an "empty", unused inode. That is
* an inode in the pseudo-filesystem that has no operations and no
* children. This is a "dangling" directory entry that has lost its
* children.
*/
inode = idir->fd_root;
if (!inode)
{
/* End of file and error conditions are not distinguishable
* with readdir. We return NULL to signal either case.
*/
ret = OK;
goto errout;
}
/* The way we handle the readdir depends on the type of inode
* that we are dealing with.
*/
#ifndef CONFIG_DISABLE_MOUNTPOINT
if (INODE_IS_MOUNTPT(inode) && !DIRENT_ISPSEUDONODE(idir->fd_flags))
{
/* 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
#endif
{
/* The node is part of the root pseudo file system */
ret = readpseudodir(idir);
}
/* ret < 0 is an error. Special case: ret = -ENOENT is end of file */
if (ret < 0)
{
if (ret == -ENOENT)
{
ret = OK;
}
goto errout;
}
/* Success */
idir->fd_position++;
return &idir->fd_dir;
errout:
set_errno(-ret);
return NULL;
}