path: root/util-linux/swaponoff.c (plain)
blob: 963139adb6f8dc618076e13c307d1f59c994c1d4

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]" 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_PRI(
16	//usage: "\n -p PRI Set swap device priority"
17	//usage: )
18	//usage:
19	//usage:#define swapoff_trivial_usage
20	//usage: "[-a] [DEVICE]"
21	//usage:#define swapoff_full_usage "\n\n"
22	//usage: "Stop swapping on DEVICE\n"
23	//usage: "\n -a Stop swapping on all swap devices"
24
25	#include "libbb.h"
26	#include <mntent.h>
27	#ifndef __BIONIC__
28	# include <sys/swap.h>
29	#endif
30
31	#if ENABLE_FEATURE_MOUNT_LABEL
32	# include "volume_id.h"
33	#else
34	# define resolve_mount_spec(fsname) ((void)0)
35	#endif
36
37	#ifndef MNTTYPE_SWAP
38	# define MNTTYPE_SWAP "swap"
39	#endif
40
41	#if ENABLE_FEATURE_SWAPON_PRI
42	struct globals {
43	int flags;
44	} FIX_ALIASING;
45	#define G (*(struct globals*)&bb_common_bufsiz1)
46	#define g_flags (G.flags)
47	#else
48	#define g_flags 0
49	#endif
50	#define INIT_G() do { } while (0)
51
52	static int swap_enable_disable(char *device)
53	{
54	int status;
55	struct stat st;
56
57	resolve_mount_spec(&device);
58	xstat(device, &st);
59
60	#if ENABLE_DESKTOP
61	/* test for holes */
62	if (S_ISREG(st.st_mode))
63	if (st.st_blocks * (off_t)512 < (uint64_t) st.st_size)
64	bb_error_msg("warning: swap file has holes");
65	#endif
66
67	if (applet_name[5] == 'n')
68	status = swapon(device, g_flags);
69	else
70	status = swapoff(device);
71
72	if (status != 0) {
73	bb_simple_perror_msg(device);
74	return 1;
75	}
76
77	return 0;
78	}
79
80	static int do_em_all(void)
81	{
82	struct mntent *m;
83	FILE *f;
84	int err;
85
86	f = setmntent("/etc/fstab", "r");
87	if (f == NULL)
88	bb_perror_msg_and_die("/etc/fstab");
89
90	err = 0;
91	while ((m = getmntent(f)) != NULL) {
92	if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
93	/* swapon -a should ignore entries with noauto,
94	* but swapoff -a should process them */
95	if (applet_name[5] != 'n'
96	|| hasmntopt(m, MNTOPT_NOAUTO) == NULL
97	) {
98	#if ENABLE_FEATURE_SWAPON_PRI
99	const char *p;
100	g_flags = 0; /* each swap space might have different flags */
101	p = hasmntopt(m, "pri");
102	if (p) {
103	/* Max allowed 32767 (==SWAP_FLAG_PRIO_MASK) */
104	unsigned int swap_prio = MIN(bb_strtou(p + 4 , NULL, 10), SWAP_FLAG_PRIO_MASK);
105	/* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */
106	if (errno != ERANGE) {
107	g_flags = SWAP_FLAG_PREFER |
108	(swap_prio << SWAP_FLAG_PRIO_SHIFT);
109	}
110	}
111	#endif
112	err += swap_enable_disable(m->mnt_fsname);
113	}
114	}
115	}
116
117	if (ENABLE_FEATURE_CLEAN_UP)
118	endmntent(f);
119
120	return err;
121	}
122
123	int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
124	int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
125	{
126	int ret;
127
128	INIT_G();
129
130	#if !ENABLE_FEATURE_SWAPON_PRI
131	ret = getopt32(argv, "a");
132	#else
133	if (applet_name[5] == 'n')
134	opt_complementary = "p+";
135	ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);
136
137	if (ret & 2) { // -p
138	g_flags = SWAP_FLAG_PREFER |
139	((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
140	ret &= 1;
141	}
142	#endif
143
144	if (ret /* & 1: not needed */) // -a
145	return do_em_all();
146
147	argv += optind;
148	if (!*argv)
149	bb_show_usage();
150
151	/* ret = 0; redundant */
152	do {
153	ret += swap_enable_disable(*argv);
154	} while (*++argv);
155
156	return ret;
157	}
158