summaryrefslogtreecommitdiff
path: root/util-linux/swaponoff.c
blob: 3f223343e0a6c2eb80eee27fa9f097ef7156856c (plain)
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
/* vi: set sw=4 ts=4: */
/*
 * Mini swapon/swapoff implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

//usage:#define swapon_trivial_usage
//usage:       "[-a]" IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
//usage:#define swapon_full_usage "\n\n"
//usage:       "Start swapping on DEVICE\n"
//usage:     "\n	-a	Start swapping on all swap devices"
//usage:	IF_FEATURE_SWAPON_PRI(
//usage:     "\n	-p PRI	Set swap device priority"
//usage:	)
//usage:
//usage:#define swapoff_trivial_usage
//usage:       "[-a] [DEVICE]"
//usage:#define swapoff_full_usage "\n\n"
//usage:       "Stop swapping on DEVICE\n"
//usage:     "\n	-a	Stop swapping on all swap devices"

#include "libbb.h"
#include <mntent.h>
#ifndef __BIONIC__
# include <sys/swap.h>
#endif

#if ENABLE_FEATURE_MOUNT_LABEL
# include "volume_id.h"
#else
# define resolve_mount_spec(fsname) ((void)0)
#endif

#ifndef MNTTYPE_SWAP
# define MNTTYPE_SWAP "swap"
#endif

#if ENABLE_FEATURE_SWAPON_PRI
struct globals {
	int flags;
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define g_flags (G.flags)
#else
#define g_flags 0
#endif
#define INIT_G() do { } while (0)

static int swap_enable_disable(char *device)
{
	int status;
	struct stat st;

	resolve_mount_spec(&device);
	xstat(device, &st);

#if ENABLE_DESKTOP
	/* test for holes */
	if (S_ISREG(st.st_mode))
		if (st.st_blocks * (off_t)512 < st.st_size)
			bb_error_msg("warning: swap file has holes");
#endif

	if (applet_name[5] == 'n')
		status = swapon(device, g_flags);
	else
		status = swapoff(device);

	if (status != 0) {
		bb_simple_perror_msg(device);
		return 1;
	}

	return 0;
}

static int do_em_all(void)
{
	struct mntent *m;
	FILE *f;
	int err;

	f = setmntent("/etc/fstab", "r");
	if (f == NULL)
		bb_perror_msg_and_die("/etc/fstab");

	err = 0;
	while ((m = getmntent(f)) != NULL) {
		if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
			/* swapon -a should ignore entries with noauto,
			 * but swapoff -a should process them */
			if (applet_name[5] != 'n'
			 || hasmntopt(m, MNTOPT_NOAUTO) == NULL
			) {
#if ENABLE_FEATURE_SWAPON_PRI
				char *p;
				g_flags = 0; /* each swap space might have different flags */
				p = hasmntopt(m, "pri");
				if (p) {
					/* Max allowed 32767 (==SWAP_FLAG_PRIO_MASK) */
					unsigned int swap_prio = MIN(bb_strtou(p + 4 , NULL, 10), SWAP_FLAG_PRIO_MASK);
					/* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */
					if (errno != ERANGE) {
						g_flags = SWAP_FLAG_PREFER |
							(swap_prio << SWAP_FLAG_PRIO_SHIFT);
					}
				}
#endif
				err += swap_enable_disable(m->mnt_fsname);
			}
		}
	}

	if (ENABLE_FEATURE_CLEAN_UP)
		endmntent(f);

	return err;
}

int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
{
	int ret;

	INIT_G();

#if !ENABLE_FEATURE_SWAPON_PRI
	ret = getopt32(argv, "a");
#else
	if (applet_name[5] == 'n')
		opt_complementary = "p+";
	ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);

	if (ret & 2) { // -p
		g_flags = SWAP_FLAG_PREFER |
			((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
		ret &= 1;
	}
#endif

	if (ret /* & 1: not needed */) // -a
		return do_em_all();

	argv += optind;
	if (!*argv)
		bb_show_usage();

	/* ret = 0; redundant */
	do {
		ret += swap_enable_disable(*argv);
	} while (*++argv);

	return ret;
}