253 lines
7.0 KiB
C
253 lines
7.0 KiB
C
/****************************************************************************
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* fs/dirent/fs_readdir.c
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*
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* Copyright (C) 2007-2009, 2011, 2017 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <string.h>
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#include <dirent.h>
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#include <errno.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/fs/dirent.h>
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#include "inode/inode.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: readpseudodir
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****************************************************************************/
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static inline int readpseudodir(struct fs_dirent_s *idir)
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{
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FAR struct inode *prev;
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/* Check if we are at the end of the list */
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if (!idir->u.pseudo.fd_next)
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{
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/* End of file and error conditions are not distinguishable
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* with readdir. Here we return -ENOENT to signal the end
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* of the directory.
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*/
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return -ENOENT;
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}
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/* Copy the inode name into the dirent structure */
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strncpy(idir->fd_dir.d_name, idir->u.pseudo.fd_next->i_name, NAME_MAX+1);
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/* If the node has file operations, we will say that it is
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* a file.
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*/
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idir->fd_dir.d_type = 0;
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if (idir->u.pseudo.fd_next->u.i_ops)
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{
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#ifndef CONFIG_DISABLE_MOUNTPOINT
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if (INODE_IS_BLOCK(idir->u.pseudo.fd_next))
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{
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idir->fd_dir.d_type |= DTYPE_BLK;
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}
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else if (INODE_IS_MOUNTPT(idir->u.pseudo.fd_next))
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{
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idir->fd_dir.d_type |= DTYPE_DIRECTORY;
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}
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else
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#endif
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#ifdef CONFIG_PSEUDOFS_SOFTLINKS
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if (INODE_IS_SOFTLINK(idir->u.pseudo.fd_next))
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{
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idir->fd_dir.d_type |= DTYPE_LINK;
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}
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else
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#endif
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{
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idir->fd_dir.d_type |= DTYPE_CHR;
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}
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}
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/* If the node has child node(s) or no operations, then we will say that
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* it is a directory rather than a special file. NOTE: that the node can
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* be both!
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*/
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if (idir->u.pseudo.fd_next->i_child || !idir->u.pseudo.fd_next->u.i_ops)
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{
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idir->fd_dir.d_type |= DTYPE_DIRECTORY;
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}
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/* Now get the inode to vist next time that readdir() is called */
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inode_semtake();
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prev = idir->u.pseudo.fd_next;
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idir->u.pseudo.fd_next = prev->i_peer; /* The next node to visit */
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if (idir->u.pseudo.fd_next)
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{
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/* Increment the reference count on this next node */
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idir->u.pseudo.fd_next->i_crefs++;
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}
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inode_semgive();
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if (prev)
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{
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inode_release(prev);
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}
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return OK;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: readdir
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*
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* Description:
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* The readdir() function returns a pointer to a dirent structure
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* representing the next directory entry in the directory stream pointed
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* to by dir. It returns NULL on reaching the end-of-file or if an error
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* occurred.
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*
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* Inputs:
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* dirp -- An instance of type DIR created by a previous call to opendir();
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*
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* Return:
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* The readdir() function returns a pointer to a dirent structure, or NULL
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* if an error occurs or end-of-file is reached. On error, errno is set
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* appropriately.
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*
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* EBADF - Invalid directory stream descriptor dir
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*
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****************************************************************************/
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FAR struct dirent *readdir(DIR *dirp)
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{
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FAR struct fs_dirent_s *idir = (struct fs_dirent_s *)dirp;
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struct inode *inode;
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int ret;
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/* Verify that we were provided with a valid directory structure */
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if (!idir)
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{
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ret = EBADF;
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goto errout;
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}
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/* A special case is when we enumerate an "empty", unused inode. That is
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* an inode in the pseudo-filesystem that has no operations and no children.
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* This is a "dangling" directory entry that has lost its children.
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*/
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inode = idir->fd_root;
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if (!inode)
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{
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/* End of file and error conditions are not distinguishable
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* with readdir. We return NULL to signal either case.
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*/
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ret = OK;
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goto errout;
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}
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/* The way we handle the readdir depends on the type of inode
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* that we are dealing with.
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*/
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#ifndef CONFIG_DISABLE_MOUNTPOINT
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if (INODE_IS_MOUNTPT(inode) && !DIRENT_ISPSEUDONODE(idir->fd_flags))
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{
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/* The node is a file system mointpoint. Verify that the mountpoint
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* supports the readdir() method
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*/
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if (!inode->u.i_mops || !inode->u.i_mops->readdir)
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{
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ret = EACCES;
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goto errout;
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}
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/* Perform the readdir() operation */
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ret = inode->u.i_mops->readdir(inode, idir);
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}
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else
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#endif
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{
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/* The node is part of the root pseudo file system */
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ret = readpseudodir(idir);
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}
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/* ret < 0 is an error. Special case: ret = -ENOENT is end of file */
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if (ret < 0)
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{
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if (ret == -ENOENT)
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{
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ret = OK;
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}
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else
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{
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ret = -ret;
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}
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goto errout;
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}
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/* Success */
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idir->fd_position++;
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return &idir->fd_dir;
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errout:
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set_errno(ret);
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return NULL;
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}
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