Contents of /tags/mkinitrd-6_2_0/util-linux/umount.c
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Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
Original Path: trunk/mkinitrd-magellan/busybox/util-linux/umount.c
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File size: 4161 byte(s)
Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
Original Path: trunk/mkinitrd-magellan/busybox/util-linux/umount.c
File MIME type: text/plain
File size: 4161 byte(s)
-import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
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 "busybox.h" |
12 | #include <mntent.h> |
13 | #include <getopt.h> |
14 | |
15 | #define OPTION_STRING "flDnravd" |
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 | |
23 | int umount_main(int argc, char **argv) |
24 | { |
25 | int doForce; |
26 | char path[2*PATH_MAX]; |
27 | struct mntent me; |
28 | FILE *fp; |
29 | int status = EXIT_SUCCESS; |
30 | unsigned opt; |
31 | struct mtab_list { |
32 | char *dir; |
33 | char *device; |
34 | struct mtab_list *next; |
35 | } *mtl, *m; |
36 | |
37 | /* Parse any options */ |
38 | |
39 | opt = getopt32(argc, argv, OPTION_STRING); |
40 | |
41 | argc -= optind; |
42 | argv += optind; |
43 | |
44 | doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY)); |
45 | |
46 | /* Get a list of mount points from mtab. We read them all in now mostly |
47 | * for umount -a (so we don't have to worry about the list changing while |
48 | * we iterate over it, or about getting stuck in a loop on the same failing |
49 | * entry. Notice that this also naturally reverses the list so that -a |
50 | * umounts the most recent entries first. */ |
51 | |
52 | m = mtl = 0; |
53 | |
54 | /* If we're umounting all, then m points to the start of the list and |
55 | * the argument list should be empty (which will match all). */ |
56 | |
57 | fp = setmntent(bb_path_mtab_file, "r"); |
58 | if (!fp) { |
59 | if (opt & OPT_ALL) |
60 | bb_error_msg_and_die("cannot open %s", bb_path_mtab_file); |
61 | } else { |
62 | while (getmntent_r(fp, &me, path, sizeof(path))) { |
63 | m = xmalloc(sizeof(struct mtab_list)); |
64 | m->next = mtl; |
65 | m->device = xstrdup(me.mnt_fsname); |
66 | m->dir = xstrdup(me.mnt_dir); |
67 | mtl = m; |
68 | } |
69 | endmntent(fp); |
70 | } |
71 | |
72 | /* If we're not umounting all, we need at least one argument. */ |
73 | if (!(opt & OPT_ALL)) { |
74 | m = 0; |
75 | if (!argc) bb_show_usage(); |
76 | } |
77 | |
78 | // Loop through everything we're supposed to umount, and do so. |
79 | for (;;) { |
80 | int curstat; |
81 | char *zapit = *argv; |
82 | |
83 | // Do we already know what to umount this time through the loop? |
84 | if (m) safe_strncpy(path, m->dir, PATH_MAX); |
85 | // For umount -a, end of mtab means time to exit. |
86 | else if (opt & OPT_ALL) break; |
87 | // Get next command line argument (and look it up in mtab list) |
88 | else if (!argc--) break; |
89 | else { |
90 | argv++; |
91 | realpath(zapit, path); |
92 | for (m = mtl; m; m = m->next) |
93 | if (!strcmp(path, m->dir) || !strcmp(path, m->device)) |
94 | break; |
95 | } |
96 | // If we couldn't find this sucker in /etc/mtab, punt by passing our |
97 | // command line argument straight to the umount syscall. Otherwise, |
98 | // umount the directory even if we were given the block device. |
99 | if (m) zapit = m->dir; |
100 | |
101 | // Let's ask the thing nicely to unmount. |
102 | curstat = umount(zapit); |
103 | |
104 | // Force the unmount, if necessary. |
105 | if (curstat && doForce) { |
106 | curstat = umount2(zapit, doForce); |
107 | if (curstat) |
108 | bb_error_msg("forced umount of %s failed!", zapit); |
109 | } |
110 | |
111 | // If still can't umount, maybe remount read-only? |
112 | if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) { |
113 | curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL); |
114 | bb_error_msg(curstat ? "cannot remount %s read-only" : |
115 | "%s busy - remounted read-only", m->device); |
116 | } |
117 | |
118 | if (curstat) { |
119 | status = EXIT_FAILURE; |
120 | bb_perror_msg("cannot umount %s", zapit); |
121 | } else { |
122 | /* De-allocate the loop device. This ioctl should be ignored on |
123 | * any non-loop block devices. */ |
124 | if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m) |
125 | del_loop(m->device); |
126 | if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m) |
127 | erase_mtab(m->dir); |
128 | } |
129 | |
130 | // Find next matching mtab entry for -a or umount /dev |
131 | // Note this means that "umount /dev/blah" will unmount all instances |
132 | // of /dev/blah, not just the most recent. |
133 | while (m && (m = m->next)) |
134 | if ((opt & OPT_ALL) || !strcmp(path, m->device)) |
135 | break; |
136 | } |
137 | |
138 | // Free mtab list if necessary |
139 | |
140 | if (ENABLE_FEATURE_CLEAN_UP) { |
141 | while (mtl) { |
142 | m = mtl->next; |
143 | free(mtl->device); |
144 | free(mtl->dir); |
145 | free(mtl); |
146 | mtl = m; |
147 | } |
148 | } |
149 | |
150 | return status; |
151 | } |