summaryrefslogtreecommitdiff
path: root/nuttx/fs/mount/fs_foreachmountpoint.c
blob: dd412a19eb1b3cb3f7e4b2d620af42f459177006 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/****************************************************************************
 * fs/mount/fs_foreachmountpoint.c
 *
 *   Copyright (C) 2012 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 <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"

#ifndef CONFIG_DISABLE_MOUNTPOUNT

/****************************************************************************
 * 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 Variables
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * 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 = strlen(dirpath);
      namlen  = strlen(node->i_name) + 1;

      /* Make sure that this would not exceed the maximum path length */

      if (pathlen + namlen > PATH_MAX)
        {
          return -ENAMETOOLONG;
        }

      /* Append the inode name to the directory path */

      sprintf(&dirpath[pathlen], "/%s", node->i_name);

      /* Get the status of the file system */

      ret = node->u.i_mops->statfs(node, &statbuf);
      if (ret == 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