Contents of /tags/mkinitrd-6_1_9/busybox/util-linux/umount.c
Parent Directory | Revision Log
Revision 919 -
(show annotations)
(download)
Wed Oct 28 00:26:51 2009 UTC (14 years, 11 months ago) by niro
File MIME type: text/plain
File size: 5260 byte(s)
Wed Oct 28 00:26:51 2009 UTC (14 years, 11 months ago) by niro
File MIME type: text/plain
File size: 5260 byte(s)
tagged 'mkinitrd-6_1_9'
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 "libbb.h" |
13 | |
14 | #if defined(__dietlibc__) |
15 | /* 16.12.2006, Sampo Kellomaki (sampo@iki.fi) |
16 | * dietlibc-0.30 does not have implementation of getmntent_r() */ |
17 | static struct mntent *getmntent_r(FILE* stream, struct mntent* result, |
18 | char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM) |
19 | { |
20 | struct mntent* ment = getmntent(stream); |
21 | return memcpy(result, ment, sizeof(*ment)); |
22 | } |
23 | #endif |
24 | |
25 | /* ignored: -v -d -t -i */ |
26 | #define OPTION_STRING "fldnra" "vdt:i" |
27 | #define OPT_FORCE (1 << 0) |
28 | #define OPT_LAZY (1 << 1) |
29 | #define OPT_FREELOOP (1 << 2) |
30 | #define OPT_NO_MTAB (1 << 3) |
31 | #define OPT_REMOUNT (1 << 4) |
32 | #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 5) : 0) |
33 | |
34 | // These constants from linux/fs.h must match OPT_FORCE and OPT_LAZY, |
35 | // otherwise "doForce" trick below won't work! |
36 | //#define MNT_FORCE 0x00000001 /* Attempt to forcibly umount */ |
37 | //#define MNT_DETACH 0x00000002 /* Just detach from the tree */ |
38 | |
39 | int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
40 | int umount_main(int argc UNUSED_PARAM, char **argv) |
41 | { |
42 | int doForce; |
43 | char *const path = xmalloc(PATH_MAX + 2); /* to save stack */ |
44 | struct mntent me; |
45 | FILE *fp; |
46 | char *fstype = NULL; |
47 | int status = EXIT_SUCCESS; |
48 | unsigned opt; |
49 | struct mtab_list { |
50 | char *dir; |
51 | char *device; |
52 | struct mtab_list *next; |
53 | } *mtl, *m; |
54 | |
55 | opt = getopt32(argv, OPTION_STRING, &fstype); |
56 | //argc -= optind; |
57 | argv += optind; |
58 | doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY)); |
59 | |
60 | /* Get a list of mount points from mtab. We read them all in now mostly |
61 | * for umount -a (so we don't have to worry about the list changing while |
62 | * we iterate over it, or about getting stuck in a loop on the same failing |
63 | * entry. Notice that this also naturally reverses the list so that -a |
64 | * umounts the most recent entries first. */ |
65 | m = mtl = NULL; |
66 | |
67 | // If we're umounting all, then m points to the start of the list and |
68 | // the argument list should be empty (which will match all). |
69 | fp = setmntent(bb_path_mtab_file, "r"); |
70 | if (!fp) { |
71 | if (opt & OPT_ALL) |
72 | bb_error_msg_and_die("can't open %s", bb_path_mtab_file); |
73 | } else { |
74 | while (getmntent_r(fp, &me, path, PATH_MAX)) { |
75 | /* Match fstype if passed */ |
76 | if (fstype && match_fstype(&me, fstype)) |
77 | continue; |
78 | m = xmalloc(sizeof(struct mtab_list)); |
79 | m->next = mtl; |
80 | m->device = xstrdup(me.mnt_fsname); |
81 | m->dir = xstrdup(me.mnt_dir); |
82 | mtl = m; |
83 | } |
84 | endmntent(fp); |
85 | } |
86 | |
87 | // If we're not umounting all, we need at least one argument. |
88 | if (!(opt & OPT_ALL) && !fstype) { |
89 | if (!argv[0]) |
90 | bb_show_usage(); |
91 | m = NULL; |
92 | } |
93 | |
94 | // Loop through everything we're supposed to umount, and do so. |
95 | for (;;) { |
96 | int curstat; |
97 | char *zapit = *argv; |
98 | |
99 | // Do we already know what to umount this time through the loop? |
100 | if (m) |
101 | safe_strncpy(path, m->dir, PATH_MAX); |
102 | // For umount -a, end of mtab means time to exit. |
103 | else if (opt & OPT_ALL) |
104 | break; |
105 | // Use command line argument (and look it up in mtab list) |
106 | else { |
107 | if (!zapit) |
108 | break; |
109 | argv++; |
110 | realpath(zapit, path); |
111 | for (m = mtl; m; m = m->next) |
112 | if (!strcmp(path, m->dir) || !strcmp(path, m->device)) |
113 | break; |
114 | } |
115 | // If we couldn't find this sucker in /etc/mtab, punt by passing our |
116 | // command line argument straight to the umount syscall. Otherwise, |
117 | // umount the directory even if we were given the block device. |
118 | if (m) zapit = m->dir; |
119 | |
120 | // Let's ask the thing nicely to unmount. |
121 | curstat = umount(zapit); |
122 | |
123 | // Force the unmount, if necessary. |
124 | if (curstat && doForce) |
125 | curstat = umount2(zapit, doForce); |
126 | |
127 | // If still can't umount, maybe remount read-only? |
128 | if (curstat) { |
129 | if ((opt & OPT_REMOUNT) && errno == EBUSY && m) { |
130 | // Note! Even if we succeed here, later we should not |
131 | // free loop device or erase mtab entry! |
132 | const char *msg = "%s busy - remounted read-only"; |
133 | curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL); |
134 | if (curstat) { |
135 | msg = "can't remount %s read-only"; |
136 | status = EXIT_FAILURE; |
137 | } |
138 | bb_error_msg(msg, m->device); |
139 | } else { |
140 | status = EXIT_FAILURE; |
141 | bb_perror_msg("can't %sumount %s", (doForce ? "forcibly " : ""), zapit); |
142 | } |
143 | } else { |
144 | // De-allocate the loop device. This ioctl should be ignored on |
145 | // any non-loop block devices. |
146 | if (ENABLE_FEATURE_MOUNT_LOOP && (opt & OPT_FREELOOP) && m) |
147 | del_loop(m->device); |
148 | if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m) |
149 | erase_mtab(m->dir); |
150 | } |
151 | |
152 | // Find next matching mtab entry for -a or umount /dev |
153 | // Note this means that "umount /dev/blah" will unmount all instances |
154 | // of /dev/blah, not just the most recent. |
155 | if (m) while ((m = m->next) != NULL) |
156 | if ((opt & OPT_ALL) || !strcmp(path, m->device)) |
157 | break; |
158 | } |
159 | |
160 | // Free mtab list if necessary |
161 | if (ENABLE_FEATURE_CLEAN_UP) { |
162 | while (mtl) { |
163 | m = mtl->next; |
164 | free(mtl->device); |
165 | free(mtl->dir); |
166 | free(mtl); |
167 | mtl = m; |
168 | } |
169 | free(path); |
170 | } |
171 | |
172 | return status; |
173 | } |