[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini swapon/swapoff implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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| 6 | *
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[2725] | 7 | * Licensed under GPLv2, see file LICENSE in this source tree.
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[821] | 8 | */
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| 9 |
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[3232] | 10 | //usage:#define swapon_trivial_usage
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[3621] | 11 | //usage: "[-a] [-e]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
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[3232] | 12 | //usage:#define swapon_full_usage "\n\n"
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| 13 | //usage: "Start swapping on DEVICE\n"
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| 14 | //usage: "\n -a Start swapping on all swap devices"
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[3621] | 15 | //usage: IF_FEATURE_SWAPON_DISCARD(
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| 16 | //usage: "\n -d[POL] Discard blocks at swapon (POL=once),"
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| 17 | //usage: "\n as freed (POL=pages), or both (POL omitted)"
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| 18 | //usage: )
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| 19 | //usage: "\n -e Silently skip devices that do not exist"
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[3232] | 20 | //usage: IF_FEATURE_SWAPON_PRI(
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| 21 | //usage: "\n -p PRI Set swap device priority"
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| 22 | //usage: )
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| 23 | //usage:
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| 24 | //usage:#define swapoff_trivial_usage
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| 25 | //usage: "[-a] [DEVICE]"
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| 26 | //usage:#define swapoff_full_usage "\n\n"
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| 27 | //usage: "Stop swapping on DEVICE\n"
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| 28 | //usage: "\n -a Stop swapping on all swap devices"
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| 29 |
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[1765] | 30 | #include "libbb.h"
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[3621] | 31 | #include "common_bufsiz.h"
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[821] | 32 | #include <mntent.h>
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[3232] | 33 | #ifndef __BIONIC__
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| 34 | # include <sys/swap.h>
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| 35 | #endif
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[821] | 36 |
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[2725] | 37 | #if ENABLE_FEATURE_MOUNT_LABEL
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| 38 | # include "volume_id.h"
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| 39 | #else
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| 40 | # define resolve_mount_spec(fsname) ((void)0)
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| 41 | #endif
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| 42 |
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[3232] | 43 | #ifndef MNTTYPE_SWAP
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| 44 | # define MNTTYPE_SWAP "swap"
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| 45 | #endif
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| 46 |
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[3621] | 47 | #if ENABLE_FEATURE_SWAPON_DISCARD
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| 48 | #ifndef SWAP_FLAG_DISCARD
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| 49 | #define SWAP_FLAG_DISCARD 0x10000
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| 50 | #endif
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| 51 | #ifndef SWAP_FLAG_DISCARD_ONCE
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| 52 | #define SWAP_FLAG_DISCARD_ONCE 0x20000
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| 53 | #endif
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| 54 | #ifndef SWAP_FLAG_DISCARD_PAGES
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| 55 | #define SWAP_FLAG_DISCARD_PAGES 0x40000
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| 56 | #endif
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| 57 | #define SWAP_FLAG_DISCARD_MASK \
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| 58 | (SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | SWAP_FLAG_DISCARD_PAGES)
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| 59 | #endif
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| 60 |
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| 61 |
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| 62 | #if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
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[2725] | 63 | struct globals {
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| 64 | int flags;
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| 65 | } FIX_ALIASING;
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[3621] | 66 | #define G (*(struct globals*)bb_common_bufsiz1)
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[2725] | 67 | #define g_flags (G.flags)
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[3621] | 68 | #define save_g_flags() int save_g_flags = g_flags
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| 69 | #define restore_g_flags() g_flags = save_g_flags
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[2725] | 70 | #else
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| 71 | #define g_flags 0
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[3621] | 72 | #define save_g_flags() ((void)0)
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| 73 | #define restore_g_flags() ((void)0)
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[2725] | 74 | #endif
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[3621] | 75 | #define INIT_G() do { setup_common_bufsiz(); } while (0)
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[2725] | 76 |
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[3621] | 77 | #define do_swapoff (applet_name[5] == 'f')
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| 78 |
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| 79 | /* Command line options */
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| 80 | enum {
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| 81 | OPTBIT_a, /* -a all */
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| 82 | OPTBIT_e, /* -e ifexists */
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| 83 | IF_FEATURE_SWAPON_DISCARD( OPTBIT_d ,) /* -d discard */
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| 84 | IF_FEATURE_SWAPON_PRI ( OPTBIT_p ,) /* -p priority */
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| 85 | OPT_a = 1 << OPTBIT_a,
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| 86 | OPT_e = 1 << OPTBIT_e,
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| 87 | OPT_d = IF_FEATURE_SWAPON_DISCARD((1 << OPTBIT_d)) + 0,
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| 88 | OPT_p = IF_FEATURE_SWAPON_PRI ((1 << OPTBIT_p)) + 0,
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| 89 | };
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| 90 |
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| 91 | #define OPT_ALL (option_mask32 & OPT_a)
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| 92 | #define OPT_DISCARD (option_mask32 & OPT_d)
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| 93 | #define OPT_IFEXISTS (option_mask32 & OPT_e)
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| 94 | #define OPT_PRIO (option_mask32 & OPT_p)
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| 95 |
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[1765] | 96 | static int swap_enable_disable(char *device)
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[821] | 97 | {
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[3621] | 98 | int err = 0;
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| 99 | int quiet = 0;
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[821] | 100 |
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[2725] | 101 | resolve_mount_spec(&device);
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[821] | 102 |
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[3621] | 103 | if (do_swapoff) {
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| 104 | err = swapoff(device);
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| 105 | /* Don't complain on OPT_ALL if not a swap device or if it doesn't exist */
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| 106 | quiet = (OPT_ALL && (errno == EINVAL || errno == ENOENT));
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| 107 | } else {
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| 108 | /* swapon */
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| 109 | struct stat st;
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| 110 | err = stat(device, &st);
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| 111 | if (!err) {
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| 112 | if (ENABLE_DESKTOP && S_ISREG(st.st_mode)) {
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| 113 | if (st.st_blocks * (off_t)512 < st.st_size) {
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| 114 | bb_error_msg("%s: file has holes", device);
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| 115 | return 1;
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| 116 | }
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| 117 | }
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| 118 | err = swapon(device, g_flags);
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| 119 | /* Don't complain on swapon -a if device is already in use */
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| 120 | quiet = (OPT_ALL && errno == EBUSY);
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| 121 | }
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| 122 | /* Don't complain if file does not exist with -e option */
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| 123 | if (err && OPT_IFEXISTS && errno == ENOENT)
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| 124 | err = 0;
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| 125 | }
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[821] | 126 |
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[3621] | 127 | if (err && !quiet) {
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[2725] | 128 | bb_simple_perror_msg(device);
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[821] | 129 | return 1;
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| 130 | }
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| 131 | return 0;
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| 132 | }
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| 133 |
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[3621] | 134 | #if ENABLE_FEATURE_SWAPON_DISCARD
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| 135 | static void set_discard_flag(char *s)
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[821] | 136 | {
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[3621] | 137 | /* Unset the flag first to allow fstab options to override */
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| 138 | /* options set on the command line */
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| 139 | g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD;
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| 140 |
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| 141 | if (!s) /* No optional policy value on the commandline */
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| 142 | return;
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| 143 | /* Skip prepended '=' */
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| 144 | if (*s == '=')
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| 145 | s++;
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| 146 | /* For fstab parsing: remove other appended options */
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| 147 | *strchrnul(s, ',') = '\0';
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| 148 |
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| 149 | if (strcmp(s, "once") == 0)
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| 150 | g_flags |= SWAP_FLAG_DISCARD_ONCE;
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| 151 | if (strcmp(s, "pages") == 0)
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| 152 | g_flags |= SWAP_FLAG_DISCARD_PAGES;
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| 153 | }
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| 154 | #else
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| 155 | #define set_discard_flag(s) ((void)0)
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| 156 | #endif
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| 157 |
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| 158 | #if ENABLE_FEATURE_SWAPON_PRI
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| 159 | static void set_priority_flag(char *s)
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| 160 | {
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| 161 | unsigned prio;
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| 162 |
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| 163 | /* For fstab parsing: remove other appended options */
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| 164 | *strchrnul(s, ',') = '\0';
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| 165 | /* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
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| 166 | prio = bb_strtou(s, NULL, 10);
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| 167 | if (!errno) {
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| 168 | /* Unset the flag first to allow fstab options to override */
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| 169 | /* options set on the command line */
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| 170 | g_flags = (g_flags & ~SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER |
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| 171 | MIN(prio, SWAP_FLAG_PRIO_MASK);
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| 172 | }
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| 173 | }
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| 174 | #else
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| 175 | #define set_priority_flag(s) ((void)0)
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| 176 | #endif
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| 177 |
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| 178 | static int do_em_all_in_fstab(void)
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| 179 | {
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[821] | 180 | struct mntent *m;
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[3621] | 181 | int err = 0;
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| 182 | FILE *f = xfopen_for_read("/etc/fstab");
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[821] | 183 |
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[2725] | 184 | while ((m = getmntent(f)) != NULL) {
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| 185 | if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
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| 186 | /* swapon -a should ignore entries with noauto,
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[3621] | 187 | * but swapoff -a should process them
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| 188 | */
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| 189 | if (do_swapoff || hasmntopt(m, MNTOPT_NOAUTO) == NULL) {
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| 190 | /* each swap space might have different flags */
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| 191 | /* save global flags for the next round */
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| 192 | save_g_flags();
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| 193 | if (ENABLE_FEATURE_SWAPON_DISCARD) {
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| 194 | char *p = hasmntopt(m, "discard");
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| 195 | if (p) {
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| 196 | /* move to '=' or to end of string */
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| 197 | p += 7;
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| 198 | set_discard_flag(p);
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| 199 | }
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| 200 | }
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| 201 | if (ENABLE_FEATURE_SWAPON_PRI) {
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| 202 | char *p = hasmntopt(m, "pri");
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| 203 | if (p) {
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| 204 | set_priority_flag(p + 4);
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| 205 | }
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| 206 | }
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| 207 | err |= swap_enable_disable(m->mnt_fsname);
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| 208 | restore_g_flags();
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[2725] | 209 | }
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| 210 | }
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| 211 | }
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[821] | 212 |
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[2725] | 213 | if (ENABLE_FEATURE_CLEAN_UP)
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| 214 | endmntent(f);
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[821] | 215 |
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| 216 | return err;
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| 217 | }
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| 218 |
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[3621] | 219 | static int do_all_in_proc_swaps(void)
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| 220 | {
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| 221 | char *line;
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| 222 | int err = 0;
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| 223 | FILE *f = fopen_for_read("/proc/swaps");
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| 224 | /* Don't complain if missing */
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| 225 | if (f) {
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| 226 | while ((line = xmalloc_fgetline(f)) != NULL) {
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| 227 | if (line[0] == '/') {
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| 228 | *strchrnul(line, ' ') = '\0';
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| 229 | err |= swap_enable_disable(line);
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| 230 | }
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| 231 | free(line);
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| 232 | }
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| 233 | if (ENABLE_FEATURE_CLEAN_UP)
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| 234 | fclose(f);
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| 235 | }
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| 236 |
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| 237 | return err;
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| 238 | }
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| 239 |
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| 240 | #define OPTSTR_SWAPON "ae" \
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| 241 | IF_FEATURE_SWAPON_DISCARD("d::") \
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| 242 | IF_FEATURE_SWAPON_PRI("p:")
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| 243 |
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[2725] | 244 | int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 245 | int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
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[821] | 246 | {
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[3621] | 247 | IF_FEATURE_SWAPON_PRI(char *prio;)
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| 248 | IF_FEATURE_SWAPON_DISCARD(char *discard = NULL;)
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| 249 | int ret = 0;
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[821] | 250 |
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[3232] | 251 | INIT_G();
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| 252 |
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[3621] | 253 | getopt32(argv, do_swapoff ? "ae" : OPTSTR_SWAPON
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| 254 | IF_FEATURE_SWAPON_DISCARD(, &discard)
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| 255 | IF_FEATURE_SWAPON_PRI(, &prio)
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| 256 | );
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[821] | 257 |
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[3621] | 258 | argv += optind;
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| 259 |
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| 260 | if (OPT_DISCARD) {
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| 261 | set_discard_flag(discard);
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[2725] | 262 | }
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[3621] | 263 | if (OPT_PRIO) {
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| 264 | set_priority_flag(prio);
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| 265 | }
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[2725] | 266 |
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[3621] | 267 | if (OPT_ALL) {
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| 268 | /* swapoff -a does also /proc/swaps */
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| 269 | if (do_swapoff)
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| 270 | ret = do_all_in_proc_swaps();
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| 271 | ret |= do_em_all_in_fstab();
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| 272 | } else if (!*argv) {
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| 273 | /* if not -a we need at least one arg */
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[2725] | 274 | bb_show_usage();
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[3621] | 275 | }
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| 276 | /* Unset -a now to allow for more messages in swap_enable_disable */
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| 277 | option_mask32 = option_mask32 & ~OPT_a;
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| 278 | /* Now process devices on the commandline if any */
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| 279 | while (*argv) {
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| 280 | ret |= swap_enable_disable(*argv++);
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| 281 | }
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[821] | 282 | return ret;
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| 283 | }
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