ext.c revision b5e694267142042228a6cac99ecad6c4b4ef8759
/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
* 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 "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];
} PACKED;
#define EXT_SUPER_MAGIC 0xEF53
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x00000004
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x00000008
#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)
{
struct ext2_super_block *es;
size_t bsize;
dbg("probing at offset 0x%llx", (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", bsize);
if (bsize < EXT3_MIN_BLOCK_SIZE || bsize > EXT3_MAX_BLOCK_SIZE) {
dbg("invalid ext blocksize");
return -1;
}
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, UUID_DCE);
snprintf(id->type_version, sizeof(id->type_version)-1,
"%u.%u", es->s_rev_level, es->s_minor_rev_level);
/* check for external journal device */
if ((le32_to_cpu(es->s_feature_incompat) & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) {
volume_id_set_usage(id, VOLUME_ID_OTHER);
id->type = "jbd";
return 0;
}
/* check for ext2 / ext3 */
volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
if ((le32_to_cpu(es->s_feature_compat) & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0)
id->type = "ext3";
else
id->type = "ext2";
return 0;
}