/****************************************************************************
* fs/fs_foreachinode.c
*
* Copyright (C) 2012-2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include "fs_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Is it better to allocate the struct inode_path_s from the heap? or
* from the stack? This decision depends on how often this is down and
* how much stack space you can afford.
*/
#define ENUM_INODE_ALLOC 1
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure manages the full path to the inode. */
struct inode_path_s
{
foreach_inode_t handler;
FAR void *arg;
char path[CONFIG_PATH_MAX];
};
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: foreach_inodelevel
*
* Description:
* This is the recursive 'heart' of foreach_inode. It will visit each
* inode at this level in the hierarchy and recurse handle each inode
* at the next level down.
*
* Assumptions:
* The caller holds the inode semaphore.
*
****************************************************************************/
int foreach_inodelevel(FAR struct inode *node, struct inode_path_s *info)
{
int ret = OK;
/* Visit each node at this level */
for (; node; node = node->i_peer)
{
/* Give the next inode to the callback */
ret = info->handler(node, info->path, info->arg);
/* Break out of the looop early if the handler returns a non-zero
* value
*/
if (ret != 0)
{
break;
}
/* If there is a level 'beneath' this one, then recurse to visit all
* of the inodes at that level.
*/
if (node->i_child)
{
/* Construct the path to the next level */
int pathlen = strlen(info->path);
int namlen = strlen(node->i_name) + 1;
/* Make sure that this would not exceed the maximum path length */
if (pathlen + namlen > PATH_MAX)
{
ret = -ENAMETOOLONG;
break;
}
/* Append the path segment to this inode and recurse */
sprintf(&info->path[pathlen], "/%s", node->i_name);
ret = foreach_inodelevel(node->i_child, info);
/* Truncate the path name back to the correct length */
info->path[pathlen] = '\0';
/* Return early if the handler at the lower level returned a non-
* zero value
*/
if (ret != 0)
{
break;
}
}
}
/* Return the result of the traversal. */
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: foreach_inode
*
* Description:
* Visit each inode in the pseudo-file system. The traversal is terminated
* when the callback 'handler' returns a non-zero value, or when all of
* the inodes have been visited.
*
* NOTE 1: Use with caution... The pseudo-file system is locked throughout
* the traversal.
* NOTE 2: The search algorithm is recursive and could, in principle, use
* an indeterminant amount of stack space. This will not usually be a
* real work issue.
*
****************************************************************************/
int foreach_inode(foreach_inode_t handler, FAR void *arg)
{
#ifdef ENUM_INODE_ALLOC
FAR struct inode_path_s *info;
int ret;
/* Allocate the mountpoint info structure */
info = (FAR struct inode_path_s *)kmalloc(sizeof(struct inode_path_s));
if (!info)
{
return -ENOMEM;
}
/* Initialize the info structure */
info->handler = handler;
info->arg = arg;
info->path[0] = '\0';
/* Start the recursion at the root inode */
inode_semtake();
ret = foreach_inodelevel(root_inode, info);
inode_semgive();
/* Free the info structure and return the result */
kfree(info);
return ret;
#else
struct inode_path_s info;
int ret;
/* Initialize the info structure */
info.handler = handler;
info.arg = arg;
info.path[0] = '\0';
/* Start the recursion at the root inode */
inode_semtake();
ret = foreach_inodelevel(root_inode, &info);
inode_semgive();
return ret;
#endif
}
