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