release/src/router/busybox/util-linux/swaponoff.c

   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         if (stat(device, &st)) {
  59                 bb_perror_msg("warning: can't stat '%s'", device);
  60                 return 1;
  61         }
  62
  63 #if ENABLE_DESKTOP
  64         /* test for holes */
  65         if (S_ISREG(st.st_mode))
  66                 if (st.st_blocks * (off_t)512 < st.st_size)
  67                         bb_error_msg("warning: swap file has holes");
  68 #endif
  69
  70         if (applet_name[5] == 'n')
  71                 status = swapon(device, g_flags);
  72         else
  73                 status = swapoff(device);
  74
  75         if (status != 0) {
  76                 bb_simple_perror_msg(device);
  77                 return 1;
  78         }
  79
  80         return 0;
  81 }
  82
  83 static int do_em_all(void)
  84 {
  85         struct mntent *m;
  86         FILE *f;
  87         int err;
  88
  89         f = setmntent("/etc/fstab", "r");
  90         if (f == NULL)
  91                 bb_perror_msg_and_die("/etc/fstab");
  92
  93         err = 0;
  94         while ((m = getmntent(f)) != NULL) {
  95                 if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
  96                         /* swapon -a should ignore entries with noauto,
  97                          * but swapoff -a should process them */
  98                         if (applet_name[5] != 'n'
  99                          || hasmntopt(m, MNTOPT_NOAUTO) == NULL
 100                         ) {
 101                                 err += swap_enable_disable(m->mnt_fsname);
 102                         }
 103                 }
 104         }
 105
 106         if (ENABLE_FEATURE_CLEAN_UP)
 107                 endmntent(f);
 108
 109         return err;
 110 }
 111
 112 int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 113 int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
 114 {
 115         int ret;
 116
 117         INIT_G();
 118
 119 #if !ENABLE_FEATURE_SWAPON_PRI
 120         ret = getopt32(argv, "a");
 121 #else
 122         if (applet_name[5] == 'n')
 123                 opt_complementary = "p+";
 124         ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);
 125
 126         if (ret & 2) { // -p
 127                 g_flags = SWAP_FLAG_PREFER |
 128                         ((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
 129                 ret &= 1;
 130         }
 131 #endif
 132
 133         if (ret /* & 1: not needed */) // -a
 134                 return do_em_all();
 135
 136         argv += optind;
 137         if (!*argv)
 138                 bb_show_usage();
 139
 140         /* ret = 0; redundant */
 141         do {
 142                 ret += swap_enable_disable(*argv);
 143         } while (*++argv);
 144
 145         return ret;
 146 }