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
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef _GNU_SOURCE
  21 #define _GNU_SOURCE 1
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <ctype.h>
  30
  31 #include "libvolume_id.h"
  32 #include "libvolume_id-private.h"
  33
  34 struct swap_header_v1_2 {
  35         uint8_t         bootbits[1024];
  36         uint32_t        version;
  37         uint32_t        last_page;
  38         uint32_t        nr_badpages;
  39         uint8_t         uuid[16];
  40         uint8_t         volume_name[16];
  41 } PACKED;
  42
  43 #define LARGEST_PAGESIZE                        0x10000
  44
  45 int volume_id_probe_linux_swap(struct volume_id *id, uint64_t off, uint64_t size)
  46 {
  47         const uint8_t *buf;
  48         unsigned int page;
  49         struct swap_header_v1_2 *sw;
  50
  51         info("probing at offset 0x%" PRIx64 "\n", off);
  52
  53         /* eek, the swap signature is at the end of the PAGE_SIZE */
  54         for (page = 0x1000; page <= LARGEST_PAGESIZE; page <<= 1) {
  55                         buf = volume_id_get_buffer(id, off + page-10, 10);
  56                         if (buf == NULL)
  57                                 return -1;
  58
  59                         if (memcmp(buf, "SWAP-SPACE", 10) == 0) {
  60                                 id->type = "swap";
  61                                 strcpy(id->type_version, "1");
  62                                 goto found;
  63                         }
  64
  65                         if (memcmp(buf, "SWAPSPACE2", 10) == 0) {
  66                                 id->type = "swap";
  67                                 strcpy(id->type_version, "2");
  68                                 goto found_label;
  69                         }
  70
  71                         if (memcmp(buf, "S1SUSPEND", 9) == 0) {
  72                                 id->type = "suspend";
  73                                 strcpy(id->type_version, "s1suspend");
  74                                 goto found_label;
  75                         }
  76
  77                         if (memcmp(buf, "ULSUSPEND", 9) == 0) {
  78                                 id->type = "suspend";
  79                                 strcpy(id->type_version, "ulsuspend");
  80                                 goto found_label;
  81                         }
  82
  83                         if (memcmp(buf, "\xed\xc3\x02\xe9\x98\x56\xe5\x0c", 8) == 0) {
  84                                 id->type = "suspend";
  85                                 strcpy(id->type_version, "tuxonice");
  86                                 goto found_label;
  87                         }
  88         }
  89         return -1;
  90
  91 found_label:
  92         sw = (struct swap_header_v1_2 *) volume_id_get_buffer(id, off, sizeof(struct swap_header_v1_2));
  93         if (sw != NULL) {
  94                 volume_id_set_label_raw(id, sw->volume_name, 16);
  95                 volume_id_set_label_string(id, sw->volume_name, 16);
  96                 volume_id_set_uuid(id, sw->uuid, 0, UUID_DCE);
  97         }
  98
  99 found:
 100         volume_id_set_usage(id, VOLUME_ID_OTHER);
 101         /* we think this is swap, but we make sure no other signatures are found */
 102         id->force_unique_result = 1;
 103         return 0;
 104 }