extras/volume_id/lib/linux_swap.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  */
  10
  11 #ifndef _GNU_SOURCE
  12 #define _GNU_SOURCE 1
  13 #endif
  14
  15 #ifdef HAVE_CONFIG_H
  16 #  include <config.h>
  17 #endif
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25
  26 #include "libvolume_id.h"
  27 #include "util.h"
  28
  29 struct swap_header_v1_2 {
  30         uint8_t         bootbits[1024];
  31         uint32_t        version;
  32         uint32_t        last_page;
  33         uint32_t        nr_badpages;
  34         uint8_t         uuid[16];
  35         uint8_t         volume_name[16];
  36 } PACKED;
  37
  38 #define LARGEST_PAGESIZE                        0x4000
  39
  40 int volume_id_probe_linux_swap(struct volume_id *id, uint64_t off, uint64_t size)
  41 {
  42         const uint8_t *buf;
  43         unsigned int page;
  44         struct swap_header_v1_2 *sw;
  45
  46         info("probing at offset 0x%llx", (unsigned long long) off);
  47
  48         /* eek, the swap signature is at the end of the PAGE_SIZE */
  49         for (page = 0x1000; page <= LARGEST_PAGESIZE; page <<= 1) {
  50                         buf = volume_id_get_buffer(id, off + page-10, 10);
  51                         if (buf == NULL)
  52                                 return -1;
  53
  54                         if (memcmp(buf, "SWAP-SPACE", 10) == 0) {
  55                                 strcpy(id->type_version, "1");
  56                                 goto found;
  57                         }
  58
  59                         if (memcmp(buf, "SWAPSPACE2", 10) == 0) {
  60                                 id->type = "swap";
  61                                 strcpy(id->type_version, "2");
  62                                 goto found_label;
  63                         }
  64
  65                         if (memcmp(buf, "S1SUSPEND", 9) == 0) {
  66                                 id->type = "suspend";
  67                                 strcpy(id->type_version, "s1suspend");
  68                                 goto found_label;
  69                         }
  70
  71                         if (memcmp(buf, "ULSUSPEND", 9) == 0) {
  72                                 id->type = "suspend";
  73                                 strcpy(id->type_version, "ulsuspend");
  74                                 goto found_label;
  75                         }
  76         }
  77         return -1;
  78
  79 found_label:
  80         sw = (struct swap_header_v1_2 *) volume_id_get_buffer(id, off, sizeof(struct swap_header_v1_2));
  81         if (sw != NULL) {
  82                 volume_id_set_label_raw(id, sw->volume_name, 16);
  83                 volume_id_set_label_string(id, sw->volume_name, 16);
  84                 volume_id_set_uuid(id, sw->uuid, 0, UUID_DCE);
  85         }
  86
  87 found:
  88         volume_id_set_usage(id, VOLUME_ID_OTHER);
  89         return 0;
  90 }