extras/volume_id/lib/ext.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2008 Theodore Ts'o <tytso@mit.edu>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #ifndef _GNU_SOURCE
  22 #define _GNU_SOURCE 1
  23 #endif
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include <ctype.h>
  31
  32 #include "libvolume_id.h"
  33 #include "libvolume_id-private.h"
  34
  35 struct ext2_super_block {
  36         uint32_t        s_inodes_count;
  37         uint32_t        s_blocks_count;
  38         uint32_t        s_r_blocks_count;
  39         uint32_t        s_free_blocks_count;
  40         uint32_t        s_free_inodes_count;
  41         uint32_t        s_first_data_block;
  42         uint32_t        s_log_block_size;
  43         uint32_t        s_log_frag_size;
  44         uint32_t        s_blocks_per_group;
  45         uint32_t        s_frags_per_group;
  46         uint32_t        s_inodes_per_group;
  47         uint32_t        s_mtime;
  48         uint32_t        s_wtime;
  49         uint16_t        s_mnt_count;
  50         uint16_t        s_max_mnt_count;
  51         uint16_t        s_magic;
  52         uint16_t        s_state;
  53         uint16_t        s_errors;
  54         uint16_t        s_minor_rev_level;
  55         uint32_t        s_lastcheck;
  56         uint32_t        s_checkinterval;
  57         uint32_t        s_creator_os;
  58         uint32_t        s_rev_level;
  59         uint16_t        s_def_resuid;
  60         uint16_t        s_def_resgid;
  61         uint32_t        s_first_ino;
  62         uint16_t        s_inode_size;
  63         uint16_t        s_block_group_nr;
  64         uint32_t        s_feature_compat;
  65         uint32_t        s_feature_incompat;
  66         uint32_t        s_feature_ro_compat;
  67         uint8_t         s_uuid[16];
  68         uint8_t         s_volume_name[16];
  69         uint8_t         s_last_mounted[64];
  70         uint32_t        s_algorithm_usage_bitmap;
  71         uint8_t         s_prealloc_blocks;
  72         uint8_t         s_prealloc_dir_blocks;
  73         uint16_t        s_reserved_gdt_blocks;
  74         uint8_t         s_journal_uuid[16];
  75         uint32_t        s_journal_inum;
  76         uint32_t        s_journal_dev;
  77         uint32_t        s_last_orphan;
  78         uint32_t        s_hash_seed[4];
  79         uint8_t         s_def_hash_version;
  80         uint8_t         s_jnl_backup_type;
  81         uint16_t        s_reserved_word_pad;
  82         uint32_t        s_default_mount_opts;
  83         uint32_t        s_first_meta_bg;
  84         uint32_t        s_mkfs_time;
  85         uint32_t        s_jnl_blocks[17];
  86         uint32_t        s_blocks_count_hi;
  87         uint32_t        s_r_blocks_count_hi;
  88         uint32_t        s_free_blocks_hi;
  89         uint16_t        s_min_extra_isize;
  90         uint16_t        s_want_extra_isize;
  91         uint32_t        s_flags;
  92 } PACKED;
  93
  94 #define EXT_SUPER_MAGIC                         0xEF53
  95 #define EXT2_FLAGS_TEST_FILESYS                 0x0004
  96 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
  97 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
  98 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
  99 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
 100 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
 101 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
 102 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
 103 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
 104
 105
 106 #define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 107                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 108                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 109 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
 110
 111 #define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 112                                          EXT2_FEATURE_INCOMPAT_META_BG)
 113 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP
 114
 115 #define EXT3_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 116                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 117                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 118 #define EXT3_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT3_FEATURE_RO_COMPAT_SUPP
 119
 120 #define EXT3_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 121                                          EXT3_FEATURE_INCOMPAT_RECOVER| \
 122                                          EXT2_FEATURE_INCOMPAT_META_BG)
 123 #define EXT3_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT3_FEATURE_INCOMPAT_SUPP
 124
 125 #define EXT_SUPERBLOCK_OFFSET                   0x400
 126 #define EXT3_MIN_BLOCK_SIZE                     0x400
 127 #define EXT3_MAX_BLOCK_SIZE                     0x1000
 128
 129 int volume_id_probe_ext(struct volume_id *id, uint64_t off, uint64_t size)
 130 {
 131         struct ext2_super_block *es;
 132         size_t bsize;
 133         uint32_t feature_compat;
 134         uint32_t feature_ro_compat;
 135         uint32_t feature_incompat;
 136         uint32_t flags;
 137
 138         info("probing at offset 0x%" PRIx64 "\n", off);
 139
 140         es = (struct ext2_super_block *) volume_id_get_buffer(id, off + EXT_SUPERBLOCK_OFFSET, 0x200);
 141         if (es == NULL)
 142                 return -1;
 143
 144         if (es->s_magic != cpu_to_le16(EXT_SUPER_MAGIC))
 145                 return -1;
 146
 147         bsize = 0x400 << le32_to_cpu(es->s_log_block_size);
 148         dbg("ext blocksize 0x%zx\n", bsize);
 149         if (bsize < EXT3_MIN_BLOCK_SIZE || bsize > EXT3_MAX_BLOCK_SIZE) {
 150                 dbg("invalid ext blocksize\n");
 151                 return -1;
 152         }
 153
 154         feature_compat = le32_to_cpu(es->s_feature_compat);
 155         feature_ro_compat = le32_to_cpu(es->s_feature_ro_compat);
 156         feature_incompat = le32_to_cpu(es->s_feature_incompat);
 157         flags = le32_to_cpu(es->s_flags);
 158
 159         /* external journal device is jbd */
 160         if ((feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) {
 161                 volume_id_set_usage(id, VOLUME_ID_OTHER);
 162                 id->type = "jbd";
 163                 goto found;
 164         }
 165
 166         /* has journal */
 167         if ((feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0) {
 168                 /* "use on development code" is ext4dev */
 169                 if ((flags & EXT2_FLAGS_TEST_FILESYS) != 0) {
 170                         id->type = "ext4dev";
 171                         goto found;
 172                 }
 173
 174                 /* incompatible ext3 features is ext4 */
 175                 if ((feature_ro_compat & EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) != 0 ||
 176                     (feature_incompat & EXT3_FEATURE_INCOMPAT_UNSUPPORTED) != 0) {
 177                         id->type = "ext4";
 178                         goto found;
 179                 }
 180
 181                 id->type = "ext3";
 182                 goto found;
 183         } else {
 184                 /* no incompatible ext2 feature is ext2 */
 185                 if ((feature_ro_compat & EXT2_FEATURE_RO_COMPAT_UNSUPPORTED) == 0 &&
 186                     (feature_incompat & EXT2_FEATURE_INCOMPAT_UNSUPPORTED) == 0) {
 187                         id->type = "ext2";
 188                         goto found;
 189                 }
 190         }
 191
 192         return -1;
 193
 194 found:
 195         volume_id_set_label_raw(id, es->s_volume_name, 16);
 196         volume_id_set_label_string(id, es->s_volume_name, 16);
 197         volume_id_set_uuid(id, es->s_uuid, 0, UUID_DCE);
 198         snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u",
 199                  le32_to_cpu(es->s_rev_level), le16_to_cpu(es->s_minor_rev_level));
 200
 201         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 202         return 0;
 203 }