source: MondoRescue/branches/3.3/mindi-busybox/util-linux/swaponoff.c

Last change on this file was 3621, checked in by Bruno Cornec, 7 years ago

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
File size: 7.1 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini swapon/swapoff implementation for busybox
4 *
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6 *
7 * Licensed under GPLv2, see file LICENSE in this source tree.
8 */
9
10//usage:#define swapon_trivial_usage
11//usage: "[-a] [-e]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
12//usage:#define swapon_full_usage "\n\n"
13//usage: "Start swapping on DEVICE\n"
14//usage: "\n -a Start swapping on all swap devices"
15//usage: IF_FEATURE_SWAPON_DISCARD(
16//usage: "\n -d[POL] Discard blocks at swapon (POL=once),"
17//usage: "\n as freed (POL=pages), or both (POL omitted)"
18//usage: )
19//usage: "\n -e Silently skip devices that do not exist"
20//usage: IF_FEATURE_SWAPON_PRI(
21//usage: "\n -p PRI Set swap device priority"
22//usage: )
23//usage:
24//usage:#define swapoff_trivial_usage
25//usage: "[-a] [DEVICE]"
26//usage:#define swapoff_full_usage "\n\n"
27//usage: "Stop swapping on DEVICE\n"
28//usage: "\n -a Stop swapping on all swap devices"
29
30#include "libbb.h"
31#include "common_bufsiz.h"
32#include <mntent.h>
33#ifndef __BIONIC__
34# include <sys/swap.h>
35#endif
36
37#if ENABLE_FEATURE_MOUNT_LABEL
38# include "volume_id.h"
39#else
40# define resolve_mount_spec(fsname) ((void)0)
41#endif
42
43#ifndef MNTTYPE_SWAP
44# define MNTTYPE_SWAP "swap"
45#endif
46
47#if ENABLE_FEATURE_SWAPON_DISCARD
48#ifndef SWAP_FLAG_DISCARD
49#define SWAP_FLAG_DISCARD 0x10000
50#endif
51#ifndef SWAP_FLAG_DISCARD_ONCE
52#define SWAP_FLAG_DISCARD_ONCE 0x20000
53#endif
54#ifndef SWAP_FLAG_DISCARD_PAGES
55#define SWAP_FLAG_DISCARD_PAGES 0x40000
56#endif
57#define SWAP_FLAG_DISCARD_MASK \
58 (SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | SWAP_FLAG_DISCARD_PAGES)
59#endif
60
61
62#if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
63struct globals {
64 int flags;
65} FIX_ALIASING;
66#define G (*(struct globals*)bb_common_bufsiz1)
67#define g_flags (G.flags)
68#define save_g_flags() int save_g_flags = g_flags
69#define restore_g_flags() g_flags = save_g_flags
70#else
71#define g_flags 0
72#define save_g_flags() ((void)0)
73#define restore_g_flags() ((void)0)
74#endif
75#define INIT_G() do { setup_common_bufsiz(); } while (0)
76
77#define do_swapoff (applet_name[5] == 'f')
78
79/* Command line options */
80enum {
81 OPTBIT_a, /* -a all */
82 OPTBIT_e, /* -e ifexists */
83 IF_FEATURE_SWAPON_DISCARD( OPTBIT_d ,) /* -d discard */
84 IF_FEATURE_SWAPON_PRI ( OPTBIT_p ,) /* -p priority */
85 OPT_a = 1 << OPTBIT_a,
86 OPT_e = 1 << OPTBIT_e,
87 OPT_d = IF_FEATURE_SWAPON_DISCARD((1 << OPTBIT_d)) + 0,
88 OPT_p = IF_FEATURE_SWAPON_PRI ((1 << OPTBIT_p)) + 0,
89};
90
91#define OPT_ALL (option_mask32 & OPT_a)
92#define OPT_DISCARD (option_mask32 & OPT_d)
93#define OPT_IFEXISTS (option_mask32 & OPT_e)
94#define OPT_PRIO (option_mask32 & OPT_p)
95
96static int swap_enable_disable(char *device)
97{
98 int err = 0;
99 int quiet = 0;
100
101 resolve_mount_spec(&device);
102
103 if (do_swapoff) {
104 err = swapoff(device);
105 /* Don't complain on OPT_ALL if not a swap device or if it doesn't exist */
106 quiet = (OPT_ALL && (errno == EINVAL || errno == ENOENT));
107 } else {
108 /* swapon */
109 struct stat st;
110 err = stat(device, &st);
111 if (!err) {
112 if (ENABLE_DESKTOP && S_ISREG(st.st_mode)) {
113 if (st.st_blocks * (off_t)512 < st.st_size) {
114 bb_error_msg("%s: file has holes", device);
115 return 1;
116 }
117 }
118 err = swapon(device, g_flags);
119 /* Don't complain on swapon -a if device is already in use */
120 quiet = (OPT_ALL && errno == EBUSY);
121 }
122 /* Don't complain if file does not exist with -e option */
123 if (err && OPT_IFEXISTS && errno == ENOENT)
124 err = 0;
125 }
126
127 if (err && !quiet) {
128 bb_simple_perror_msg(device);
129 return 1;
130 }
131 return 0;
132}
133
134#if ENABLE_FEATURE_SWAPON_DISCARD
135static void set_discard_flag(char *s)
136{
137 /* Unset the flag first to allow fstab options to override */
138 /* options set on the command line */
139 g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD;
140
141 if (!s) /* No optional policy value on the commandline */
142 return;
143 /* Skip prepended '=' */
144 if (*s == '=')
145 s++;
146 /* For fstab parsing: remove other appended options */
147 *strchrnul(s, ',') = '\0';
148
149 if (strcmp(s, "once") == 0)
150 g_flags |= SWAP_FLAG_DISCARD_ONCE;
151 if (strcmp(s, "pages") == 0)
152 g_flags |= SWAP_FLAG_DISCARD_PAGES;
153}
154#else
155#define set_discard_flag(s) ((void)0)
156#endif
157
158#if ENABLE_FEATURE_SWAPON_PRI
159static void set_priority_flag(char *s)
160{
161 unsigned prio;
162
163 /* For fstab parsing: remove other appended options */
164 *strchrnul(s, ',') = '\0';
165 /* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
166 prio = bb_strtou(s, NULL, 10);
167 if (!errno) {
168 /* Unset the flag first to allow fstab options to override */
169 /* options set on the command line */
170 g_flags = (g_flags & ~SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER |
171 MIN(prio, SWAP_FLAG_PRIO_MASK);
172 }
173}
174#else
175#define set_priority_flag(s) ((void)0)
176#endif
177
178static int do_em_all_in_fstab(void)
179{
180 struct mntent *m;
181 int err = 0;
182 FILE *f = xfopen_for_read("/etc/fstab");
183
184 while ((m = getmntent(f)) != NULL) {
185 if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
186 /* swapon -a should ignore entries with noauto,
187 * but swapoff -a should process them
188 */
189 if (do_swapoff || hasmntopt(m, MNTOPT_NOAUTO) == NULL) {
190 /* each swap space might have different flags */
191 /* save global flags for the next round */
192 save_g_flags();
193 if (ENABLE_FEATURE_SWAPON_DISCARD) {
194 char *p = hasmntopt(m, "discard");
195 if (p) {
196 /* move to '=' or to end of string */
197 p += 7;
198 set_discard_flag(p);
199 }
200 }
201 if (ENABLE_FEATURE_SWAPON_PRI) {
202 char *p = hasmntopt(m, "pri");
203 if (p) {
204 set_priority_flag(p + 4);
205 }
206 }
207 err |= swap_enable_disable(m->mnt_fsname);
208 restore_g_flags();
209 }
210 }
211 }
212
213 if (ENABLE_FEATURE_CLEAN_UP)
214 endmntent(f);
215
216 return err;
217}
218
219static int do_all_in_proc_swaps(void)
220{
221 char *line;
222 int err = 0;
223 FILE *f = fopen_for_read("/proc/swaps");
224 /* Don't complain if missing */
225 if (f) {
226 while ((line = xmalloc_fgetline(f)) != NULL) {
227 if (line[0] == '/') {
228 *strchrnul(line, ' ') = '\0';
229 err |= swap_enable_disable(line);
230 }
231 free(line);
232 }
233 if (ENABLE_FEATURE_CLEAN_UP)
234 fclose(f);
235 }
236
237 return err;
238}
239
240#define OPTSTR_SWAPON "ae" \
241 IF_FEATURE_SWAPON_DISCARD("d::") \
242 IF_FEATURE_SWAPON_PRI("p:")
243
244int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
245int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
246{
247 IF_FEATURE_SWAPON_PRI(char *prio;)
248 IF_FEATURE_SWAPON_DISCARD(char *discard = NULL;)
249 int ret = 0;
250
251 INIT_G();
252
253 getopt32(argv, do_swapoff ? "ae" : OPTSTR_SWAPON
254 IF_FEATURE_SWAPON_DISCARD(, &discard)
255 IF_FEATURE_SWAPON_PRI(, &prio)
256 );
257
258 argv += optind;
259
260 if (OPT_DISCARD) {
261 set_discard_flag(discard);
262 }
263 if (OPT_PRIO) {
264 set_priority_flag(prio);
265 }
266
267 if (OPT_ALL) {
268 /* swapoff -a does also /proc/swaps */
269 if (do_swapoff)
270 ret = do_all_in_proc_swaps();
271 ret |= do_em_all_in_fstab();
272 } else if (!*argv) {
273 /* if not -a we need at least one arg */
274 bb_show_usage();
275 }
276 /* Unset -a now to allow for more messages in swap_enable_disable */
277 option_mask32 = option_mask32 & ~OPT_a;
278 /* Now process devices on the commandline if any */
279 while (*argv) {
280 ret |= swap_enable_disable(*argv++);
281 }
282 return ret;
283}
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