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:     "\nOptions:"
  15 //usage:     "\n        -a      Start swapping on all swap devices"
  16 //usage:        IF_FEATURE_SWAPON_PRI(
  17 //usage:     "\n        -p PRI  Set swap device priority"
  18 //usage:        )
  19 //usage:
  20 //usage:#define swapoff_trivial_usage
  21 //usage:       "[-a] [DEVICE]"
  22 //usage:#define swapoff_full_usage "\n\n"
  23 //usage:       "Stop swapping on DEVICE\n"
  24 //usage:     "\nOptions:"
  25 //usage:     "\n        -a      Stop swapping on all swap devices"
  26
  27 #include "libbb.h"
  28 #include <mntent.h>
  29 #include <sys/swap.h>
  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 #if ENABLE_FEATURE_SWAPON_PRI
  38 struct globals {
  39         int flags;
  40 } FIX_ALIASING;
  41 #define G (*(struct globals*)&bb_common_bufsiz1)
  42 #define g_flags (G.flags)
  43 #else
  44 #define g_flags 0
  45 #endif
  46
  47 static int swap_enable_disable(char *device)
  48 {
  49         int status;
  50         struct stat st;
  51
  52         resolve_mount_spec(&device);
  53         xstat(device, &st);
  54
  55 #if ENABLE_DESKTOP
  56         /* test for holes */
  57         if (S_ISREG(st.st_mode))
  58                 if (st.st_blocks * (off_t)512 < st.st_size)
  59                         bb_error_msg("warning: swap file has holes");
  60 #endif
  61
  62         if (applet_name[5] == 'n')
  63                 status = swapon(device, g_flags);
  64         else
  65                 status = swapoff(device);
  66
  67         if (status != 0) {
  68                 bb_simple_perror_msg(device);
  69                 return 1;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int do_em_all(void)
  76 {
  77         struct mntent *m;
  78         FILE *f;
  79         int err;
  80
  81         f = setmntent("/etc/fstab", "r");
  82         if (f == NULL)
  83                 bb_perror_msg_and_die("/etc/fstab");
  84
  85         err = 0;
  86         while ((m = getmntent(f)) != NULL) {
  87                 if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
  88                         /* swapon -a should ignore entries with noauto,
  89                          * but swapoff -a should process them */
  90                         if (applet_name[5] != 'n'
  91                          || hasmntopt(m, MNTOPT_NOAUTO) == NULL
  92                         ) {
  93                                 err += swap_enable_disable(m->mnt_fsname);
  94                         }
  95                 }
  96         }
  97
  98         if (ENABLE_FEATURE_CLEAN_UP)
  99                 endmntent(f);
 100
 101         return err;
 102 }
 103
 104 int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 105 int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
 106 {
 107         int ret;
 108
 109 #if !ENABLE_FEATURE_SWAPON_PRI
 110         ret = getopt32(argv, "a");
 111 #else
 112         opt_complementary = "p+";
 113         ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);
 114
 115         if (ret & 2) { // -p
 116                 g_flags = SWAP_FLAG_PREFER |
 117                         ((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
 118                 ret &= 1;
 119         }
 120 #endif
 121
 122         if (ret /* & 1: not needed */) // -a
 123                 return do_em_all();
 124
 125         argv += optind;
 126         if (!*argv)
 127                 bb_show_usage();
 128
 129         /* ret = 0; redundant */
 130         do {
 131                 ret += swap_enable_disable(*argv);
 132         } while (*++argv);
 133
 134         return ret;
 135 }