incubator-nuttx/fs/mount/fs_foreachmountpoint.c

156 lines
5.0 KiB
C

/****************************************************************************
* fs/mount/fs_foreachmountpoint.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 <sys/statfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include "inode/inode.h"
#include "mount/mount.h"
#ifndef CONFIG_DISABLE_MOUNTPOINT
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure just remembers the final consumer of the mountpoint
* information (and its argument).
*/
struct enum_mountpoint_s
{
foreach_mountpoint_t handler;
FAR void *arg;
};
/****************************************************************************
* Private Functions
****************************************************************************/
static int mountpoint_filter(FAR struct inode *node,
FAR char dirpath[PATH_MAX], FAR void *arg)
{
FAR struct enum_mountpoint_s *info = (FAR struct enum_mountpoint_s *)arg;
struct statfs statbuf;
int pathlen;
int namlen;
int ret = OK;
DEBUGASSERT(node && info && info->handler);
/* Check if the inode is a mountpoint. Mountpoints must support statfs.
* If this one does not for some reason, then it will be ignored.
*
* The root node is a special case: It has no operations (u.i_mops == NULL)
*/
if (INODE_IS_MOUNTPT(node) && node->u.i_mops && node->u.i_mops->statfs)
{
/* Yes... get the full path to the inode by concatenating the inode
* name and the path to the directory containing the inode.
*/
pathlen = strnlen(dirpath, PATH_MAX);
namlen = strnlen(node->i_name, PATH_MAX) + 1;
/* Make sure that this would not exceed the maximum path length */
if (pathlen + namlen > PATH_MAX)
{
return OK;
}
/* Append the inode name to the directory path */
snprintf(&dirpath[pathlen], PATH_MAX - pathlen, "/%s", node->i_name);
/* Get the status of the file system */
memset(&statbuf, 0, sizeof(struct statfs));
if (node->u.i_mops->statfs(node, &statbuf) == OK)
{
/* And pass the full path and file system status to the handler */
ret = info->handler(dirpath, &statbuf, info->arg);
}
/* Truncate the path name back to the correct length */
dirpath[pathlen] = '\0';
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: foreach_mountpoint
*
* Description:
* Visit each mountpoint in the pseudo-file system. The traversal is
* terminated when the callback 'handler' returns a non-zero value, or when
* all of the mountpoints have been visited.
*
* This is just a front end "filter" to foreach_inode() that forwards only
* mountpoint inodes. It is intended to support the mount() command to
* when the mount command is used to enumerate mounts.
*
* 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_mountpoint(foreach_mountpoint_t handler, FAR void *arg)
{
struct enum_mountpoint_s info;
/* Let foreach_inode do the real work */
info.handler = handler;
info.arg = arg;
return foreach_inode(mountpoint_filter, (FAR void *)&info);
}
#endif