util-linux/volume_id/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 library is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU Lesser General Public
   8  *      License as published by the Free Software Foundation; either
   9  *      version 2.1 of the License, or (at your option) any later version.
  10  *
  11  *      This library 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 GNU
  14  *      Lesser General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU Lesser General Public
  17  *      License along with this library; if not, write to the Free Software
  18  *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  */
  20
  21 //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_LINUXSWAP) += linux_swap.o
  22
  23 //config:config FEATURE_VOLUMEID_LINUXSWAP
  24 //config:       bool "linux swap filesystem"
  25 //config:       default y
  26 //config:       depends on VOLUMEID
  27
  28 #include "volume_id_internal.h"
  29
  30 struct swap_header_v1_2 {
  31         uint8_t         bootbits[1024];
  32         uint32_t        version;
  33         uint32_t        last_page;
  34         uint32_t        nr_badpages;
  35         uint8_t         uuid[16];
  36         uint8_t         volume_name[16];
  37 } PACKED;
  38
  39 #define LARGEST_PAGESIZE                        0x4000
  40
  41 int FAST_FUNC volume_id_probe_linux_swap(struct volume_id *id /*,uint64_t off*/)
  42 {
  43 #define off ((uint64_t)0)
  44         struct swap_header_v1_2 *sw;
  45         const uint8_t *buf;
  46         unsigned page;
  47
  48         dbg("probing at offset 0x%llx", (unsigned long long) off);
  49
  50         /* the swap signature is at the end of the PAGE_SIZE */
  51         for (page = 0x1000; page <= LARGEST_PAGESIZE; page <<= 1) {
  52                         buf = volume_id_get_buffer(id, off + page-10, 10);
  53                         if (buf == NULL)
  54                                 return -1;
  55
  56                         if (memcmp(buf, "SWAP-SPACE", 10) == 0) {
  57 //                              id->type_version[0] = '1';
  58 //                              id->type_version[1] = '\0';
  59                                 goto found;
  60                         }
  61
  62                         if (memcmp(buf, "SWAPSPACE2", 10) == 0
  63                          || memcmp(buf, "S1SUSPEND", 9) == 0
  64                          || memcmp(buf, "S2SUSPEND", 9) == 0
  65                          || memcmp(buf, "ULSUSPEND", 9) == 0
  66                         ) {
  67                                 sw = volume_id_get_buffer(id, off, sizeof(struct swap_header_v1_2));
  68                                 if (sw == NULL)
  69                                         return -1;
  70 //                              id->type_version[0] = '2';
  71 //                              id->type_version[1] = '\0';
  72 //                              volume_id_set_label_raw(id, sw->volume_name, 16);
  73                                 volume_id_set_label_string(id, sw->volume_name, 16);
  74                                 volume_id_set_uuid(id, sw->uuid, UUID_DCE);
  75                                 goto found;
  76                         }
  77         }
  78         return -1;
  79
  80 found:
  81 //      volume_id_set_usage(id, VOLUME_ID_OTHER);
  82         IF_FEATURE_BLKID_TYPE(id->type = "swap";)
  83
  84         return 0;
  85 }