1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
|
/* vi: set sw=4 ts=4: */
/*
* Mini umount implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2005 by Rob Landley <rob@landley.net>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//usage:#define umount_trivial_usage
//usage: "[OPTIONS] FILESYSTEM|DIRECTORY"
//usage:#define umount_full_usage "\n\n"
//usage: "Unmount file systems\n"
//usage: IF_FEATURE_UMOUNT_ALL(
//usage: "\n -a Unmount all file systems" IF_FEATURE_MTAB_SUPPORT(" in /etc/mtab")
//usage: )
//usage: IF_FEATURE_MTAB_SUPPORT(
//usage: "\n -n Don't erase /etc/mtab entries"
//usage: )
//usage: "\n -r Try to remount devices as read-only if mount is busy"
//usage: "\n -l Lazy umount (detach filesystem)"
//usage: "\n -f Force umount (i.e., unreachable NFS server)"
//usage: IF_FEATURE_MOUNT_LOOP(
//usage: "\n -D Don't free loop device even if it has been used"
//usage: )
//usage:
//usage:#define umount_example_usage
//usage: "$ umount /dev/hdc1\n"
#include <mntent.h>
#include <sys/mount.h>
#ifndef MNT_DETACH
# define MNT_DETACH 0x00000002
#endif
#include "libbb.h"
#if defined(__dietlibc__)
// TODO: This does not belong here.
/* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
* dietlibc-0.30 does not have implementation of getmntent_r() */
static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM)
{
struct mntent* ment = getmntent(stream);
return memcpy(result, ment, sizeof(*ment));
}
#endif
/* Ignored: -v -t -i
* bbox always acts as if -d is present.
* -D can be used to suppress it (bbox extension).
* Rationale:
* (1) util-linux's umount does it if "loop=..." is seen in /etc/mtab:
* thus, on many systems, bare umount _does_ drop loop devices.
* (2) many users request this feature.
*/
#define OPTION_STRING "fldDnra" "vt:i"
#define OPT_FORCE (1 << 0) // Same as MNT_FORCE
#define OPT_LAZY (1 << 1) // Same as MNT_DETACH
//#define OPT_FREE_LOOP (1 << 2) // -d is assumed always present
#define OPT_DONT_FREE_LOOP (1 << 3)
#define OPT_NO_MTAB (1 << 4)
#define OPT_REMOUNT (1 << 5)
#define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 6) : 0)
int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int umount_main(int argc UNUSED_PARAM, char **argv)
{
int doForce;
struct mntent me;
FILE *fp;
char *fstype = NULL;
int status = EXIT_SUCCESS;
unsigned opt;
struct mtab_list {
char *dir;
char *device;
struct mtab_list *next;
} *mtl, *m;
opt = getopt32(argv, OPTION_STRING, &fstype);
//argc -= optind;
argv += optind;
// MNT_FORCE and MNT_DETACH (from linux/fs.h) must match
// OPT_FORCE and OPT_LAZY.
BUILD_BUG_ON(OPT_FORCE != MNT_FORCE || OPT_LAZY != MNT_DETACH);
doForce = opt & (OPT_FORCE|OPT_LAZY);
/* Get a list of mount points from mtab. We read them all in now mostly
* for umount -a (so we don't have to worry about the list changing while
* we iterate over it, or about getting stuck in a loop on the same failing
* entry. Notice that this also naturally reverses the list so that -a
* umounts the most recent entries first. */
m = mtl = NULL;
// If we're umounting all, then m points to the start of the list and
// the argument list should be empty (which will match all).
fp = setmntent(bb_path_mtab_file, "r");
if (!fp) {
if (opt & OPT_ALL)
bb_error_msg_and_die("can't open '%s'", bb_path_mtab_file);
} else {
while (getmntent_r(fp, &me, bb_common_bufsiz1, sizeof(bb_common_bufsiz1))) {
/* Match fstype if passed */
if (!match_fstype(&me, fstype))
continue;
m = xzalloc(sizeof(*m));
m->next = mtl;
m->device = xstrdup(me.mnt_fsname);
m->dir = xstrdup(me.mnt_dir);
mtl = m;
}
endmntent(fp);
}
// If we're not umounting all, we need at least one argument.
if (!(opt & OPT_ALL) && !fstype) {
if (!argv[0])
bb_show_usage();
m = NULL;
}
// Loop through everything we're supposed to umount, and do so.
for (;;) {
int curstat;
char *zapit = *argv;
char *path;
// Do we already know what to umount this time through the loop?
if (m)
path = xstrdup(m->dir);
// For umount -a, end of mtab means time to exit.
else if (opt & OPT_ALL)
break;
// Use command line argument (and look it up in mtab list)
else {
if (!zapit)
break;
argv++;
path = xmalloc_realpath(zapit);
if (path) {
for (m = mtl; m; m = m->next)
if (strcmp(path, m->dir) == 0 || strcmp(path, m->device) == 0)
break;
}
}
// If we couldn't find this sucker in /etc/mtab, punt by passing our
// command line argument straight to the umount syscall. Otherwise,
// umount the directory even if we were given the block device.
if (m) zapit = m->dir;
// umount from util-linux 2.22.2 does not do this:
// umount -f uses umount2(MNT_FORCE) immediately,
// not trying umount() first.
// (Strangely, umount -fl ignores -f: it is equivalent to umount -l.
// We do pass both flags in this case)
#if 0
// Let's ask the thing nicely to unmount.
curstat = umount(zapit);
// Unmount with force and/or lazy flags, if necessary.
if (curstat && doForce)
#endif
curstat = umount2(zapit, doForce);
// If still can't umount, maybe remount read-only?
if (curstat) {
if ((opt & OPT_REMOUNT) && errno == EBUSY && m) {
// Note! Even if we succeed here, later we should not
// free loop device or erase mtab entry!
const char *msg = "%s busy - remounted read-only";
curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
if (curstat) {
msg = "can't remount %s read-only";
status = EXIT_FAILURE;
}
bb_error_msg(msg, m->device);
} else {
status = EXIT_FAILURE;
bb_perror_msg("can't unmount %s", zapit);
}
} else {
// De-allocate the loop device. This ioctl should be ignored on
// any non-loop block devices.
if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONT_FREE_LOOP) && m)
del_loop(m->device);
if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
erase_mtab(m->dir);
}
// Find next matching mtab entry for -a or umount /dev
// Note this means that "umount /dev/blah" will unmount all instances
// of /dev/blah, not just the most recent.
if (m) {
while ((m = m->next) != NULL)
// NB: if m is non-NULL, path is non-NULL as well
if ((opt & OPT_ALL) || strcmp(path, m->device) == 0)
break;
}
free(path);
}
// Free mtab list if necessary
if (ENABLE_FEATURE_CLEAN_UP) {
while (mtl) {
m = mtl->next;
free(mtl->device);
free(mtl->dir);
free(mtl);
mtl = m;
}
}
return status;
}
|
