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  * The probe logic is based on libblkid from e2fsutils.
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License as published by the
  11  *      Free Software Foundation version 2 of the License.
  12  */
  13
  14 #ifndef _GNU_SOURCE
  15 #define _GNU_SOURCE 1
  16 #endif
  17
  18 #ifdef HAVE_CONFIG_H
  19 #  include <config.h>
  20 #endif
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25 #include <string.h>
  26 #include <errno.h>
  27 #include <ctype.h>
  28
  29 #include "libvolume_id.h"
  30 #include "util.h"
  31
  32 struct ext2_super_block {
  33         uint32_t        s_inodes_count;
  34         uint32_t        s_blocks_count;
  35         uint32_t        s_r_blocks_count;
  36         uint32_t        s_free_blocks_count;
  37         uint32_t        s_free_inodes_count;
  38         uint32_t        s_first_data_block;
  39         uint32_t        s_log_block_size;
  40         uint32_t        s_log_frag_size;
  41         uint32_t        s_blocks_per_group;
  42         uint32_t        s_frags_per_group;
  43         uint32_t        s_inodes_per_group;
  44         uint32_t        s_mtime;
  45         uint32_t        s_wtime;
  46         uint16_t        s_mnt_count;
  47         uint16_t        s_max_mnt_count;
  48         uint16_t        s_magic;
  49         uint16_t        s_state;
  50         uint16_t        s_errors;
  51         uint16_t        s_minor_rev_level;
  52         uint32_t        s_lastcheck;
  53         uint32_t        s_checkinterval;
  54         uint32_t        s_creator_os;
  55         uint32_t        s_rev_level;
  56         uint16_t        s_def_resuid;
  57         uint16_t        s_def_resgid;
  58         uint32_t        s_first_ino;
  59         uint16_t        s_inode_size;
  60         uint16_t        s_block_group_nr;
  61         uint32_t        s_feature_compat;
  62         uint32_t        s_feature_incompat;
  63         uint32_t        s_feature_ro_compat;
  64         uint8_t         s_uuid[16];
  65         uint8_t         s_volume_name[16];
  66         uint8_t         s_last_mounted[64];
  67         uint32_t        s_algorithm_usage_bitmap;
  68         uint8_t         s_prealloc_blocks;
  69         uint8_t         s_prealloc_dir_blocks;
  70         uint16_t        s_reserved_gdt_blocks;
  71         uint8_t         s_journal_uuid[16];
  72         uint32_t        s_journal_inum;
  73         uint32_t        s_journal_dev;
  74         uint32_t        s_last_orphan;
  75         uint32_t        s_hash_seed[4];
  76         uint8_t         s_def_hash_version;
  77         uint8_t         s_jnl_backup_type;
  78         uint16_t        s_reserved_word_pad;
  79         uint32_t        s_default_mount_opts;
  80         uint32_t        s_first_meta_bg;
  81         uint32_t        s_mkfs_time;
  82         uint32_t        s_jnl_blocks[17];
  83         uint32_t        s_blocks_count_hi;
  84         uint32_t        s_r_blocks_count_hi;
  85         uint32_t        s_free_blocks_hi;
  86         uint16_t        s_min_extra_isize;
  87         uint16_t        s_want_extra_isize;
  88         uint32_t        s_flags;
  89 } PACKED;
  90
  91 #define EXT_SUPER_MAGIC                         0xEF53
  92 #define EXT2_FLAGS_TEST_FILESYS                 0x0004
  93 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
  94 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
  95 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
  96 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
  97 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
  98 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
  99 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
 100 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
 101
 102
 103 #define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 104                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 105                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 106 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
 107
 108 #define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 109                                          EXT2_FEATURE_INCOMPAT_META_BG)
 110 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP
 111
 112 #define EXT3_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 113                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 114                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 115 #define EXT3_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT3_FEATURE_RO_COMPAT_SUPP
 116
 117 #define EXT3_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 118                                          EXT3_FEATURE_INCOMPAT_RECOVER| \
 119                                          EXT2_FEATURE_INCOMPAT_META_BG)
 120 #define EXT3_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT3_FEATURE_INCOMPAT_SUPP
 121
 122 #define EXT_SUPERBLOCK_OFFSET                   0x400
 123 #define EXT3_MIN_BLOCK_SIZE                     0x400
 124 #define EXT3_MAX_BLOCK_SIZE                     0x1000
 125
 126 int volume_id_probe_ext(struct volume_id *id, uint64_t off, uint64_t size)
 127 {
 128         struct ext2_super_block *es;
 129         size_t bsize;
 130         uint32_t feature_compat;
 131         uint32_t feature_ro_compat;
 132         uint32_t feature_incompat;
 133         uint32_t flags;
 134
 135         info("probing at offset 0x%llx", (unsigned long long) off);
 136
 137         es = (struct ext2_super_block *) volume_id_get_buffer(id, off + EXT_SUPERBLOCK_OFFSET, 0x200);
 138         if (es == NULL)
 139                 return -1;
 140
 141         if (es->s_magic != cpu_to_le16(EXT_SUPER_MAGIC))
 142                 return -1;
 143
 144         bsize = 0x400 << le32_to_cpu(es->s_log_block_size);
 145         dbg("ext blocksize 0x%zx", bsize);
 146         if (bsize < EXT3_MIN_BLOCK_SIZE || bsize > EXT3_MAX_BLOCK_SIZE) {
 147                 dbg("invalid ext blocksize");
 148                 return -1;
 149         }
 150
 151         feature_compat = le32_to_cpu(es->s_feature_compat);
 152         feature_ro_compat = le32_to_cpu(es->s_feature_ro_compat);
 153         feature_incompat = le32_to_cpu(es->s_feature_incompat);
 154         flags = le32_to_cpu(es->s_flags);
 155
 156         /* external journal device is jbd */
 157         if ((feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) {
 158                 volume_id_set_usage(id, VOLUME_ID_OTHER);
 159                 id->type = "jbd";
 160                 goto found;
 161         }
 162
 163         /* has journal */
 164         if ((feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0) {
 165                 /* "use on development code" is ext4dev */
 166                 if ((flags & EXT2_FLAGS_TEST_FILESYS) != 0) {
 167                         id->type = "ext4dev";
 168                         goto found;
 169                 }
 170
 171                 /* incompatible ext3 features is ext4 */
 172                 if ((feature_ro_compat & EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) != 0 ||
 173                     (feature_incompat & EXT3_FEATURE_INCOMPAT_UNSUPPORTED) != 0) {
 174                         id->type = "ext4";
 175                         goto found;
 176                 }
 177
 178                 id->type = "ext3";
 179                 goto found;
 180         } else {
 181                 /* no incompatible ext2 feature is ext2 */
 182                 if ((feature_ro_compat & EXT2_FEATURE_RO_COMPAT_UNSUPPORTED) == 0 &&
 183                     (feature_incompat & EXT2_FEATURE_INCOMPAT_UNSUPPORTED) == 0) {
 184                         id->type = "ext2";
 185                         goto found;
 186                 }
 187         }
 188
 189         return -1;
 190
 191 found:
 192         volume_id_set_label_raw(id, es->s_volume_name, 16);
 193         volume_id_set_label_string(id, es->s_volume_name, 16);
 194         volume_id_set_uuid(id, es->s_uuid, 0, UUID_DCE);
 195         snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u",
 196                  le32_to_cpu(es->s_rev_level), le16_to_cpu(es->s_minor_rev_level));
 197
 198         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 199         return 0;
 200 }