1/* 2 * volume_id - reads filesystem label and uuid 3 * 4 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the 8 * Free Software Foundation version 2 of the License. 9 */ 10 11#ifndef _GNU_SOURCE 12#define _GNU_SOURCE 1 13#endif 14 15#ifdef HAVE_CONFIG_H 16# include <config.h> 17#endif 18 19#include <stdio.h> 20#include <stdlib.h> 21#include <unistd.h> 22#include <string.h> 23#include <errno.h> 24#include <ctype.h> 25 26#include "libvolume_id.h" 27#include "util.h" 28 29struct ext2_super_block { 30 uint32_t s_inodes_count; 31 uint32_t s_blocks_count; 32 uint32_t s_r_blocks_count; 33 uint32_t s_free_blocks_count; 34 uint32_t s_free_inodes_count; 35 uint32_t s_first_data_block; 36 uint32_t s_log_block_size; 37 uint32_t s_log_frag_size; 38 uint32_t s_blocks_per_group; 39 uint32_t s_frags_per_group; 40 uint32_t s_inodes_per_group; 41 uint32_t s_mtime; 42 uint32_t s_wtime; 43 uint16_t s_mnt_count; 44 uint16_t s_max_mnt_count; 45 uint16_t s_magic; 46 uint16_t s_state; 47 uint16_t s_errors; 48 uint16_t s_minor_rev_level; 49 uint32_t s_lastcheck; 50 uint32_t s_checkinterval; 51 uint32_t s_creator_os; 52 uint32_t s_rev_level; 53 uint16_t s_def_resuid; 54 uint16_t s_def_resgid; 55 uint32_t s_first_ino; 56 uint16_t s_inode_size; 57 uint16_t s_block_group_nr; 58 uint32_t s_feature_compat; 59 uint32_t s_feature_incompat; 60 uint32_t s_feature_ro_compat; 61 uint8_t s_uuid[16]; 62 uint8_t s_volume_name[16]; 63} PACKED; 64 65#define EXT_SUPER_MAGIC 0xEF53 66#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x00000004 67#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x00000008 68#define EXT_SUPERBLOCK_OFFSET 0x400 69 70#define EXT3_MIN_BLOCK_SIZE 0x400 71#define EXT3_MAX_BLOCK_SIZE 0x1000 72 73int volume_id_probe_ext(struct volume_id *id, uint64_t off, uint64_t size) 74{ 75 struct ext2_super_block *es; 76 size_t bsize; 77 78 info("probing at offset 0x%llx", (unsigned long long) off); 79 80 es = (struct ext2_super_block *) volume_id_get_buffer(id, off + EXT_SUPERBLOCK_OFFSET, 0x200); 81 if (es == NULL) 82 return -1; 83 84 if (es->s_magic != cpu_to_le16(EXT_SUPER_MAGIC)) 85 return -1; 86 87 bsize = 0x400 << le32_to_cpu(es->s_log_block_size); 88 dbg("ext blocksize 0x%zx", bsize); 89 if (bsize < EXT3_MIN_BLOCK_SIZE || bsize > EXT3_MAX_BLOCK_SIZE) { 90 dbg("invalid ext blocksize"); 91 return -1; 92 } 93 94 volume_id_set_label_raw(id, es->s_volume_name, 16); 95 volume_id_set_label_string(id, es->s_volume_name, 16); 96 volume_id_set_uuid(id, es->s_uuid, 0, UUID_DCE); 97 snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u", 98 le32_to_cpu(es->s_rev_level), le16_to_cpu(es->s_minor_rev_level)); 99 100 /* check for external journal device */ 101 if ((le32_to_cpu(es->s_feature_incompat) & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) { 102 volume_id_set_usage(id, VOLUME_ID_OTHER); 103 id->type = "jbd"; 104 return 0; 105 } 106 107 /* check for ext2 / ext3 */ 108 volume_id_set_usage(id, VOLUME_ID_FILESYSTEM); 109 if ((le32_to_cpu(es->s_feature_compat) & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0) 110 id->type = "ext3"; 111 else 112 id->type = "ext2"; 113 114 return 0; 115} 116