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         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 < 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                                 err += swap_enable_disable(m->mnt_fsname);
  99                         }
 100                 }
 101         }
 102
 103         if (ENABLE_FEATURE_CLEAN_UP)
 104                 endmntent(f);
 105
 106         return err;
 107 }
 108
 109 int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 110 int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
 111 {
 112         int ret;
 113
 114         INIT_G();
 115
 116 #if !ENABLE_FEATURE_SWAPON_PRI
 117         ret = getopt32(argv, "a");
 118 #else
 119         if (applet_name[5] == 'n')
 120                 opt_complementary = "p+";
 121         ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);
 122
 123         if (ret & 2) { // -p
 124                 g_flags = SWAP_FLAG_PREFER |
 125                         ((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
 126                 ret &= 1;
 127         }
 128 #endif
 129
 130         if (ret /* & 1: not needed */) // -a
 131                 return do_em_all();
 132
 133         argv += optind;
 134         if (!*argv)
 135                 bb_show_usage();
 136
 137         /* ret = 0; redundant */
 138         do {
 139                 ret += swap_enable_disable(*argv);
 140         } while (*++argv);
 141
 142         return ret;
 143 }