source: branches/stable/mindi-busybox/util-linux/umount.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 4.0 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 * This program is licensed under the GNU General Public license (GPL)
9 * version 2 or later, see http://www.fsf.org/licensing/licenses/gpl.html
10 * or the file "LICENSE" in the busybox source tarball for the full text.
11 *
12 */
13
14#include "busybox.h"
15#include <mntent.h>
16#include <errno.h>
17#include <string.h>
18#include <getopt.h>
19
20#define OPTION_STRING       "flDnrvad"
21#define OPT_FORCE           1
22#define OPT_LAZY            2
23#define OPT_DONTFREELOOP    4
24#define OPT_NO_MTAB         8
25#define OPT_REMOUNT         16
26#define OPT_IGNORED         32  // -v is ignored
27#define OPT_ALL             (ENABLE_FEATURE_UMOUNT_ALL ? 64 : 0)
28
29int umount_main(int argc, char **argv)
30{
31    int doForce;
32    char path[2*PATH_MAX];
33    struct mntent me;
34    FILE *fp;
35    int status = EXIT_SUCCESS;
36    unsigned long opt;
37    struct mtab_list {
38        char *dir;
39        char *device;
40        struct mtab_list *next;
41    } *mtl, *m;
42
43    /* Parse any options */
44
45    opt = bb_getopt_ulflags(argc, argv, OPTION_STRING);
46
47    argc -= optind;
48    argv += optind;
49
50    doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
51
52    /* Get a list of mount points from mtab.  We read them all in now mostly
53     * for umount -a (so we don't have to worry about the list changing while
54     * we iterate over it, or about getting stuck in a loop on the same failing
55     * entry.  Notice that this also naturally reverses the list so that -a
56     * umounts the most recent entries first. */
57
58    m = mtl = 0;
59
60    /* If we're umounting all, then m points to the start of the list and
61     * the argument list should be empty (which will match all). */
62
63    if (!(fp = setmntent(bb_path_mtab_file, "r"))) {
64        if (opt & OPT_ALL)
65            bb_error_msg_and_die("Cannot open %s", bb_path_mtab_file);
66    } else while (getmntent_r(fp,&me,path,sizeof(path))) {
67        m = xmalloc(sizeof(struct mtab_list));
68        m->next = mtl;
69        m->device = bb_xstrdup(me.mnt_fsname);
70        m->dir = bb_xstrdup(me.mnt_dir);
71        mtl = m;
72    }
73    endmntent(fp);
74
75    /* If we're not mounting all, we need at least one argument. */
76    if (!(opt & OPT_ALL)) {
77        m = 0;
78        if (!argc) bb_show_usage();
79    }
80
81
82   
83    // Loop through everything we're supposed to umount, and do so.
84    for (;;) {
85        int curstat;
86
87        // Do we already know what to umount this time through the loop?
88        if (m) safe_strncpy(path, m->dir, PATH_MAX);
89        // For umount -a, end of mtab means time to exit.
90        else if (opt & OPT_ALL) break;
91        // Get next command line argument (and look it up in mtab list)
92        else if (!argc--) break;
93        else {
94            realpath(*argv++, path);
95            for (m = mtl; m; m = m->next)
96                if (!strcmp(path, m->dir) || !strcmp(path, m->device))
97                    break;
98        }
99
100        // Let's ask the thing nicely to unmount.
101        curstat = umount(path);
102
103        // Force the unmount, if necessary.
104        if (curstat && doForce) {
105            curstat = umount2(path, doForce);
106            if (curstat)
107                bb_error_msg_and_die("forced umount of %s failed!", path);
108        }
109
110        // If still can't umount, maybe remount read-only?
111        if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
112            curstat = mount(m->device, path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
113            bb_error_msg(curstat ? "Cannot remount %s read-only" :
114                         "%s busy - remounted read-only", m->device);
115        }
116
117        /* De-allocate the loop device.  This ioctl should be ignored on any
118         * non-loop block devices. */
119        if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
120            del_loop(m->device);
121
122        if (curstat) {
123            /* Yes, the ENABLE is redundant here, but the optimizer for ARM
124             * can't do simple constant propagation in local variables... */
125            if(ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
126                erase_mtab(m->dir);
127            status = EXIT_FAILURE;
128            bb_perror_msg("Couldn't umount %s", path);
129        }
130        // Find next matching mtab entry for -a or umount /dev
131        while (m && (m = m->next))
132            if ((opt & OPT_ALL) || !strcmp(path,m->device))
133                break;
134    }
135
136    // Free mtab list if necessary
137
138    if (ENABLE_FEATURE_CLEAN_UP) {
139        while (mtl) {
140            m = mtl->next;
141            free(mtl->device);
142            free(mtl->dir);
143            free(mtl);
144            mtl=m;
145        }
146    }
147
148    return status;
149}
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