source: branches/3.2/mindi-busybox/libbb/find_mount_point.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 1.7 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Utility routines.
4 *
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 */
9
10#include "libbb.h"
11#include <mntent.h>
12
13/*
14 * Given a block device, find the mount table entry if that block device
15 * is mounted.
16 *
17 * Given any other file (or directory), find the mount table entry for its
18 * filesystem.
19 */
20struct mntent* FAST_FUNC find_mount_point(const char *name, int subdir_too)
21{
22    struct stat s;
23    FILE *mtab_fp;
24    struct mntent *mountEntry;
25    dev_t devno_of_name;
26    bool block_dev;
27
28    if (stat(name, &s) != 0)
29        return NULL;
30
31    devno_of_name = s.st_dev;
32    block_dev = 0;
33    /* Why S_ISCHR? - UBI volumes use char devices, not block */
34    if (S_ISBLK(s.st_mode) || S_ISCHR(s.st_mode)) {
35        devno_of_name = s.st_rdev;
36        block_dev = 1;
37    }
38
39    mtab_fp = setmntent(bb_path_mtab_file, "r");
40    if (!mtab_fp)
41        return NULL;
42
43    while ((mountEntry = getmntent(mtab_fp)) != NULL) {
44        /* rootfs mount in Linux 2.6 exists always,
45         * and it makes sense to always ignore it.
46         * Otherwise people can't reference their "real" root! */
47        if (ENABLE_FEATURE_SKIP_ROOTFS && strcmp(mountEntry->mnt_fsname, "rootfs") == 0)
48            continue;
49
50        if (strcmp(name, mountEntry->mnt_dir) == 0
51         || strcmp(name, mountEntry->mnt_fsname) == 0
52        ) { /* String match. */
53            break;
54        }
55
56        if (!(subdir_too || block_dev))
57            continue;
58
59        /* Is device's dev_t == name's dev_t? */
60        if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == devno_of_name)
61            break;
62        /* Match the directory's mount point. */
63        if (stat(mountEntry->mnt_dir, &s) == 0 && s.st_dev == devno_of_name)
64            break;
65    }
66    endmntent(mtab_fp);
67
68    return mountEntry;
69}
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