source: MondoRescue/branches/2.2.5/mindi-busybox/util-linux/umount.c @ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 13 years ago

Update to busybox 1.7.2

File size: 4.2 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini umount implementation for busybox
4 *
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6 * Copyright (C) 2005 by Rob Landley <rob@landley.net>
7 *
8 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
9 */
10
11#include <mntent.h>
12#include <getopt.h>
13#include "libbb.h"
14
15#define OPTION_STRING       "flDnravdt:"
16#define OPT_FORCE           1
17#define OPT_LAZY            2
18#define OPT_DONTFREELOOP    4
19#define OPT_NO_MTAB         8
20#define OPT_REMOUNT         16
21#define OPT_ALL             (ENABLE_FEATURE_UMOUNT_ALL ? 32 : 0)
22
23int umount_main(int argc, char **argv);
24int umount_main(int argc, char **argv)
25{
26    int doForce;
27    char path[2*PATH_MAX];
28    struct mntent me;
29    FILE *fp;
30    char *fstype = 0;
31    int status = EXIT_SUCCESS;
32    unsigned opt;
33    struct mtab_list {
34        char *dir;
35        char *device;
36        struct mtab_list *next;
37    } *mtl, *m;
38
39    /* Parse any options */
40
41    opt = getopt32(argv, OPTION_STRING, &fstype);
42
43    argc -= optind;
44    argv += optind;
45
46    doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
47
48    /* Get a list of mount points from mtab.  We read them all in now mostly
49     * for umount -a (so we don't have to worry about the list changing while
50     * we iterate over it, or about getting stuck in a loop on the same failing
51     * entry.  Notice that this also naturally reverses the list so that -a
52     * umounts the most recent entries first. */
53
54    m = mtl = 0;
55
56    /* If we're umounting all, then m points to the start of the list and
57     * the argument list should be empty (which will match all). */
58
59    fp = setmntent(bb_path_mtab_file, "r");
60    if (!fp) {
61        if (opt & OPT_ALL)
62            bb_error_msg_and_die("cannot open %s", bb_path_mtab_file);
63    } else {
64        while (getmntent_r(fp, &me, path, sizeof(path))) {
65            /* Match fstype if passed */
66            if (fstype && match_fstype(&me, fstype))
67                continue;
68            m = xmalloc(sizeof(struct mtab_list));
69            m->next = mtl;
70            m->device = xstrdup(me.mnt_fsname);
71            m->dir = xstrdup(me.mnt_dir);
72            mtl = m;
73        }
74        endmntent(fp);
75    }
76
77    /* If we're not umounting all, we need at least one argument. */
78    if (!(opt & OPT_ALL) && !fstype) {
79        m = 0;
80        if (!argc) bb_show_usage();
81    }
82
83    // Loop through everything we're supposed to umount, and do so.
84    for (;;) {
85        int curstat;
86        char *zapit = *argv;
87
88        // Do we already know what to umount this time through the loop?
89        if (m) safe_strncpy(path, m->dir, PATH_MAX);
90        // For umount -a, end of mtab means time to exit.
91        else if (opt & OPT_ALL) break;
92        // Get next command line argument (and look it up in mtab list)
93        else if (!argc--) break;
94        else {
95            argv++;
96            realpath(zapit, path);
97            for (m = mtl; m; m = m->next)
98                if (!strcmp(path, m->dir) || !strcmp(path, m->device))
99                    break;
100        }
101        // If we couldn't find this sucker in /etc/mtab, punt by passing our
102        // command line argument straight to the umount syscall.  Otherwise,
103        // umount the directory even if we were given the block device.
104        if (m) zapit = m->dir;
105
106        // Let's ask the thing nicely to unmount.
107        curstat = umount(zapit);
108
109        // Force the unmount, if necessary.
110        if (curstat && doForce) {
111            curstat = umount2(zapit, doForce);
112            if (curstat)
113                bb_error_msg("forced umount of %s failed!", zapit);
114        }
115
116        // If still can't umount, maybe remount read-only?
117        if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
118            curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
119            bb_error_msg(curstat ? "cannot remount %s read-only" :
120                         "%s busy - remounted read-only", m->device);
121        }
122
123        if (curstat) {
124            status = EXIT_FAILURE;
125            bb_perror_msg("cannot umount %s", zapit);
126        } else {
127            /* De-allocate the loop device.  This ioctl should be ignored on
128             * any non-loop block devices. */
129            if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
130                del_loop(m->device);
131            if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
132                erase_mtab(m->dir);
133        }
134
135        // Find next matching mtab entry for -a or umount /dev
136        // Note this means that "umount /dev/blah" will unmount all instances
137        // of /dev/blah, not just the most recent.
138        while (m && (m = m->next))
139            if ((opt & OPT_ALL) || !strcmp(path, m->device))
140                break;
141    }
142
143    // Free mtab list if necessary
144
145    if (ENABLE_FEATURE_CLEAN_UP) {
146        while (mtl) {
147            m = mtl->next;
148            free(mtl->device);
149            free(mtl->dir);
150            free(mtl);
151            mtl = m;
152        }
153    }
154
155    return status;
156}
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