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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7 | * Licensed under GPLv2, see file LICENSE in this source tree.
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8 | */
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9 |
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10 | //usage:#define swapon_trivial_usage
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11 | //usage: "[-a] [-e]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
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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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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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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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30 | #include "libbb.h"
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31 | #include "common_bufsiz.h"
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32 | #include <mntent.h>
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33 | #ifndef __BIONIC__
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34 | # include <sys/swap.h>
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35 | #endif
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36 |
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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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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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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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63 | struct globals {
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64 | int flags;
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65 | } FIX_ALIASING;
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66 | #define G (*(struct globals*)bb_common_bufsiz1)
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67 | #define g_flags (G.flags)
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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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70 | #else
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71 | #define g_flags 0
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72 | #define save_g_flags() ((void)0)
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73 | #define restore_g_flags() ((void)0)
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74 | #endif
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75 | #define INIT_G() do { setup_common_bufsiz(); } while (0)
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76 |
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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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96 | static int swap_enable_disable(char *device)
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97 | {
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98 | int err = 0;
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99 | int quiet = 0;
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100 |
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101 | resolve_mount_spec(&device);
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102 |
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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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126 |
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127 | if (err && !quiet) {
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128 | bb_simple_perror_msg(device);
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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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134 | #if ENABLE_FEATURE_SWAPON_DISCARD
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135 | static void set_discard_flag(char *s)
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136 | {
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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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180 | struct mntent *m;
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181 | int err = 0;
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182 | FILE *f = xfopen_for_read("/etc/fstab");
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183 |
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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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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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209 | }
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210 | }
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211 | }
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212 |
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213 | if (ENABLE_FEATURE_CLEAN_UP)
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214 | endmntent(f);
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215 |
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216 | return err;
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217 | }
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218 |
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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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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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246 | {
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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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250 |
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251 | INIT_G();
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252 |
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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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257 |
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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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262 | }
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263 | if (OPT_PRIO) {
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264 | set_priority_flag(prio);
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265 | }
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266 |
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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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274 | bb_show_usage();
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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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282 | return ret;
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283 | }
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