ext.c revision 2603474ff9be2418900581da1af5cccc9f13cae1
/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
* Copyright (C) 2008 Theodore Ts'o <tytso@mit.edu>
*
* The probe logic is based on libblkid from e2fsutils.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include "libvolume_id.h"
#include "libvolume_id-private.h"
#include "util.h"
struct ext2_super_block {
uint32_t s_inodes_count;
uint32_t s_blocks_count;
uint32_t s_r_blocks_count;
uint32_t s_free_blocks_count;
uint32_t s_free_inodes_count;
uint32_t s_first_data_block;
uint32_t s_log_block_size;
uint32_t s_log_frag_size;
uint32_t s_blocks_per_group;
uint32_t s_frags_per_group;
uint32_t s_inodes_per_group;
uint32_t s_mtime;
uint32_t s_wtime;
uint16_t s_mnt_count;
uint16_t s_max_mnt_count;
uint16_t s_magic;
uint16_t s_state;
uint16_t s_errors;
uint16_t s_minor_rev_level;
uint32_t s_lastcheck;
uint32_t s_checkinterval;
uint32_t s_creator_os;
uint32_t s_rev_level;
uint16_t s_def_resuid;
uint16_t s_def_resgid;
uint32_t s_first_ino;
uint16_t s_inode_size;
uint16_t s_block_group_nr;
uint32_t s_feature_compat;
uint32_t s_feature_incompat;
uint32_t s_feature_ro_compat;
uint8_t s_uuid[16];
uint8_t s_volume_name[16];
uint8_t s_last_mounted[64];
uint32_t s_algorithm_usage_bitmap;
uint8_t s_prealloc_blocks;
uint8_t s_prealloc_dir_blocks;
uint16_t s_reserved_gdt_blocks;
uint8_t s_journal_uuid[16];
uint32_t s_journal_inum;
uint32_t s_journal_dev;
uint32_t s_last_orphan;
uint32_t s_hash_seed[4];
uint8_t s_def_hash_version;
uint8_t s_jnl_backup_type;
uint16_t s_reserved_word_pad;
uint32_t s_default_mount_opts;
uint32_t s_first_meta_bg;
uint32_t s_mkfs_time;
uint32_t s_jnl_blocks[17];
uint32_t s_blocks_count_hi;
uint32_t s_r_blocks_count_hi;
uint32_t s_free_blocks_hi;
uint16_t s_min_extra_isize;
uint16_t s_want_extra_isize;
uint32_t s_flags;
} PACKED;
#define EXT_SUPER_MAGIC 0xEF53
#define EXT2_FLAGS_TEST_FILESYS 0x0004
#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
#define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED ~EXT2_FEATURE_RO_COMPAT_SUPP
#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT2_FEATURE_INCOMPAT_UNSUPPORTED ~EXT2_FEATURE_INCOMPAT_SUPP
#define EXT3_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
#define EXT3_FEATURE_RO_COMPAT_UNSUPPORTED ~EXT3_FEATURE_RO_COMPAT_SUPP
#define EXT3_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
EXT3_FEATURE_INCOMPAT_RECOVER| \
EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT3_FEATURE_INCOMPAT_UNSUPPORTED ~EXT3_FEATURE_INCOMPAT_SUPP
#define EXT_SUPERBLOCK_OFFSET 0x400
#define EXT3_MIN_BLOCK_SIZE 0x400
#define EXT3_MAX_BLOCK_SIZE 0x1000
int volume_id_probe_ext(struct volume_id *id, uint64_t off, uint64_t size)
{
struct ext2_super_block *es;
size_t bsize;
uint32_t feature_compat;
uint32_t feature_ro_compat;
uint32_t feature_incompat;
uint32_t flags;
info("probing at offset 0x%llx\n", (unsigned long long) off);
es = (struct ext2_super_block *) volume_id_get_buffer(id, off + EXT_SUPERBLOCK_OFFSET, 0x200);
if (es == NULL)
return -1;
if (es->s_magic != cpu_to_le16(EXT_SUPER_MAGIC))
return -1;
bsize = 0x400 << le32_to_cpu(es->s_log_block_size);
dbg("ext blocksize 0x%zx\n", bsize);
if (bsize < EXT3_MIN_BLOCK_SIZE || bsize > EXT3_MAX_BLOCK_SIZE) {
dbg("invalid ext blocksize\n");
return -1;
}
feature_compat = le32_to_cpu(es->s_feature_compat);
feature_ro_compat = le32_to_cpu(es->s_feature_ro_compat);
feature_incompat = le32_to_cpu(es->s_feature_incompat);
flags = le32_to_cpu(es->s_flags);
/* external journal device is jbd */
if ((feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) {
volume_id_set_usage(id, VOLUME_ID_OTHER);
id->type = "jbd";
goto found;
}
/* has journal */
if ((feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0) {
/* "use on development code" is ext4dev */
if ((flags & EXT2_FLAGS_TEST_FILESYS) != 0) {
id->type = "ext4dev";
goto found;
}
/* incompatible ext3 features is ext4 */
if ((feature_ro_compat & EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) != 0 ||
(feature_incompat & EXT3_FEATURE_INCOMPAT_UNSUPPORTED) != 0) {
id->type = "ext4";
goto found;
}
id->type = "ext3";
goto found;
} else {
/* no incompatible ext2 feature is ext2 */
if ((feature_ro_compat & EXT2_FEATURE_RO_COMPAT_UNSUPPORTED) == 0 &&
(feature_incompat & EXT2_FEATURE_INCOMPAT_UNSUPPORTED) == 0) {
id->type = "ext2";
goto found;
}
}
return -1;
found:
volume_id_set_label_raw(id, es->s_volume_name, 16);
volume_id_set_label_string(id, es->s_volume_name, 16);
volume_id_set_uuid(id, es->s_uuid, 0, UUID_DCE);
snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u",
le32_to_cpu(es->s_rev_level), le16_to_cpu(es->s_minor_rev_level));
volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
return 0;
}