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 #include <sys/swap.h>
  28 #ifndef __BIONIC__
  29 # include <sys/swap.h>
  30 #endif
  31
  32 #if ENABLE_FEATURE_MOUNT_LABEL
  33 # include "volume_id.h"
  34 #else
  35 # define resolve_mount_spec(fsname) ((void)0)
  36 #endif
  37
  38 #ifndef MNTTYPE_SWAP
  39 # define MNTTYPE_SWAP "swap"
  40 #endif
  41
  42 #if ENABLE_FEATURE_SWAPON_PRI
  43 struct globals {
  44         int flags;
  45 } FIX_ALIASING;
  46 #define G (*(struct globals*)&bb_common_bufsiz1)
  47 #define g_flags (G.flags)
  48 #else
  49 #define g_flags 0
  50 #endif
  51 #define INIT_G() do { } while (0)
  52
  53 static int swap_enable_disable(char *device)
  54 {
  55         int status;
  56         struct stat st;
  57
  58         resolve_mount_spec(&device);
  59         xstat(device, &st);
  60
  61 #if ENABLE_DESKTOP
  62         /* test for holes */
  63         if (S_ISREG(st.st_mode))
  64                 if (st.st_blocks * (off_t)512 < st.st_size)
  65                         bb_error_msg("warning: swap file has holes");
  66 #endif
  67
  68         if (applet_name[5] == 'n')
  69                 status = swapon(device, g_flags);
  70         else
  71                 status = swapoff(device);
  72
  73         if (status != 0) {
  74                 bb_simple_perror_msg(device);
  75                 return 1;
  76         }
  77
  78         return 0;
  79 }
  80
  81 static int do_em_all(void)
  82 {
  83         struct mntent *m;
  84         FILE *f;
  85         int err;
  86
  87         f = setmntent("/etc/fstab", "r");
  88         if (f == NULL)
  89                 bb_perror_msg_and_die("/etc/fstab");
  90
  91         err = 0;
  92         while ((m = getmntent(f)) != NULL) {
  93                 if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
  94                         /* swapon -a should ignore entries with noauto,
  95                          * but swapoff -a should process them */
  96                         if (applet_name[5] != 'n'
  97                          || hasmntopt(m, MNTOPT_NOAUTO) == NULL
  98                         ) {
  99                                 err += swap_enable_disable(m->mnt_fsname);
 100                         }
 101                 }
 102         }
 103
 104         if (ENABLE_FEATURE_CLEAN_UP)
 105                 endmntent(f);
 106
 107         return err;
 108 }
 109
 110 int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 111 int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
 112 {
 113         int ret;
 114
 115         INIT_G();
 116
 117 #if !ENABLE_FEATURE_SWAPON_PRI
 118         ret = getopt32(argv, "a");
 119 #else
 120         if (applet_name[5] == 'n')
 121                 opt_complementary = "p+";
 122         ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);
 123
 124         if (ret & 2) { // -p
 125                 g_flags = SWAP_FLAG_PREFER |
 126                         ((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
 127                 ret &= 1;
 128         }
 129 #endif
 130
 131         if (ret /* & 1: not needed */) // -a
 132                 return do_em_all();
 133
 134         argv += optind;
 135         if (!*argv)
 136                 bb_show_usage();
 137
 138         /* ret = 0; redundant */
 139         do {
 140                 ret += swap_enable_disable(*argv);
 141         } while (*++argv);
 142
 143         return ret;
 144 }