extras/volume_id/lib/hfs.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef _GNU_SOURCE
  21 #define _GNU_SOURCE 1
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <ctype.h>
  30
  31 #include "libvolume_id.h"
  32 #include "libvolume_id-private.h"
  33 #include "md5.h"
  34
  35 struct hfs_finder_info{
  36         uint32_t        boot_folder;
  37         uint32_t        start_app;
  38         uint32_t        open_folder;
  39         uint32_t        os9_folder;
  40         uint32_t        reserved;
  41         uint32_t        osx_folder;
  42         uint8_t         id[8];
  43 } PACKED;
  44
  45 static struct hfs_mdb {
  46         uint8_t         signature[2];
  47         uint32_t        cr_date;
  48         uint32_t        ls_Mod;
  49         uint16_t        atrb;
  50         uint16_t        nm_fls;
  51         uint16_t        vbm_st;
  52         uint16_t        alloc_ptr;
  53         uint16_t        nm_al_blks;
  54         uint32_t        al_blk_size;
  55         uint32_t        clp_size;
  56         uint16_t        al_bl_st;
  57         uint32_t        nxt_cnid;
  58         uint16_t        free_bks;
  59         uint8_t         label_len;
  60         uint8_t         label[27];
  61         uint32_t        vol_bkup;
  62         uint16_t        vol_seq_num;
  63         uint32_t        wr_cnt;
  64         uint32_t        xt_clump_size;
  65         uint32_t        ct_clump_size;
  66         uint16_t        num_root_dirs;
  67         uint32_t        file_count;
  68         uint32_t        dir_count;
  69         struct hfs_finder_info finder_info;
  70         uint8_t         embed_sig[2];
  71         uint16_t        embed_startblock;
  72         uint16_t        embed_blockcount;
  73 } PACKED *hfs;
  74
  75 struct hfsplus_bnode_descriptor {
  76         uint32_t        next;
  77         uint32_t        prev;
  78         uint8_t         type;
  79         uint8_t         height;
  80         uint16_t        num_recs;
  81         uint16_t        reserved;
  82 } PACKED;
  83
  84 struct hfsplus_bheader_record {
  85         uint16_t        depth;
  86         uint32_t        root;
  87         uint32_t        leaf_count;
  88         uint32_t        leaf_head;
  89         uint32_t        leaf_tail;
  90         uint16_t        node_size;
  91 } PACKED;
  92
  93 struct hfsplus_catalog_key {
  94         uint16_t        key_len;
  95         uint32_t        parent_id;
  96         uint16_t        unicode_len;
  97         uint8_t         unicode[255 * 2];
  98 } PACKED;
  99
 100 struct hfsplus_extent {
 101         uint32_t        start_block;
 102         uint32_t        block_count;
 103 } PACKED;
 104
 105 #define HFSPLUS_EXTENT_COUNT            8
 106 struct hfsplus_fork {
 107         uint64_t        total_size;
 108         uint32_t        clump_size;
 109         uint32_t        total_blocks;
 110         struct hfsplus_extent extents[HFSPLUS_EXTENT_COUNT];
 111 } PACKED;
 112
 113 static struct hfsplus_vol_header {
 114         uint8_t         signature[2];
 115         uint16_t        version;
 116         uint32_t        attributes;
 117         uint32_t        last_mount_vers;
 118         uint32_t        reserved;
 119         uint32_t        create_date;
 120         uint32_t        modify_date;
 121         uint32_t        backup_date;
 122         uint32_t        checked_date;
 123         uint32_t        file_count;
 124         uint32_t        folder_count;
 125         uint32_t        blocksize;
 126         uint32_t        total_blocks;
 127         uint32_t        free_blocks;
 128         uint32_t        next_alloc;
 129         uint32_t        rsrc_clump_sz;
 130         uint32_t        data_clump_sz;
 131         uint32_t        next_cnid;
 132         uint32_t        write_count;
 133         uint64_t        encodings_bmp;
 134         struct hfs_finder_info finder_info;
 135         struct hfsplus_fork alloc_file;
 136         struct hfsplus_fork ext_file;
 137         struct hfsplus_fork cat_file;
 138         struct hfsplus_fork attr_file;
 139         struct hfsplus_fork start_file;
 140 } PACKED *hfsplus;
 141
 142 #define HFS_SUPERBLOCK_OFFSET           0x400
 143 #define HFS_NODE_LEAF                   0xff
 144 #define HFSPLUS_POR_CNID                1
 145
 146 static void hfsid_set_uuid(struct volume_id *id, const uint8_t *hfs_id)
 147 {
 148         struct md5_ctx md5c;
 149         static const uint8_t hash_init[16] = {
 150                 0xb3, 0xe2, 0x0f, 0x39, 0xf2, 0x92, 0x11, 0xd6,
 151                 0x97, 0xa4, 0x00, 0x30, 0x65, 0x43, 0xec, 0xac
 152         };
 153         uint8_t uuid[16];
 154
 155         if (*((uint64_t *)hfs_id) == 0)
 156                 return;
 157
 158         md5_init(&md5c);
 159         md5_update(&md5c, hash_init, 16);
 160         md5_update(&md5c, hfs_id, 8);
 161         md5_final(&md5c, uuid);
 162
 163         uuid[6] = 0x30 | (uuid[6] & 0x0f);
 164         uuid[8] = 0x80 | (uuid[8] & 0x3f);
 165         volume_id_set_uuid(id, uuid, 0, UUID_DCE);
 166 }
 167
 168 int volume_id_probe_hfs_hfsplus(struct volume_id *id, uint64_t off, uint64_t size)
 169 {
 170         unsigned int blocksize;
 171         unsigned int cat_block;
 172         unsigned int ext_block_start;
 173         unsigned int ext_block_count;
 174         int ext;
 175         unsigned int leaf_node_head;
 176         unsigned int leaf_node_count;
 177         unsigned int leaf_node_size;
 178         unsigned int leaf_block;
 179         uint64_t leaf_off;
 180         unsigned int alloc_block_size;
 181         unsigned int alloc_first_block;
 182         unsigned int embed_first_block;
 183         unsigned int record_count;
 184         struct hfsplus_bnode_descriptor *descr;
 185         struct hfsplus_bheader_record *bnode;
 186         struct hfsplus_catalog_key *key;
 187         unsigned int label_len;
 188         struct hfsplus_extent extents[HFSPLUS_EXTENT_COUNT];
 189         const uint8_t *buf;
 190
 191         info("probing at offset 0x%llx\n", (unsigned long long) off);
 192
 193         buf = volume_id_get_buffer(id, off + HFS_SUPERBLOCK_OFFSET, 0x200);
 194         if (buf == NULL)
 195                 return -1;
 196
 197         hfs = (struct hfs_mdb *) buf;
 198         if (memcmp(hfs->signature, "BD", 2) != 0)
 199                 goto checkplus;
 200
 201         /* it may be just a hfs wrapper for hfs+ */
 202         if (memcmp(hfs->embed_sig, "H+", 2) == 0) {
 203                 alloc_block_size = be32_to_cpu(hfs->al_blk_size);
 204                 dbg("alloc_block_size 0x%x\n", alloc_block_size);
 205
 206                 alloc_first_block = be16_to_cpu(hfs->al_bl_st);
 207                 dbg("alloc_first_block 0x%x\n", alloc_first_block);
 208
 209                 embed_first_block = be16_to_cpu(hfs->embed_startblock);
 210                 dbg("embed_first_block 0x%x\n", embed_first_block);
 211
 212                 off += (alloc_first_block * 512) +
 213                        (embed_first_block * alloc_block_size);
 214                 dbg("hfs wrapped hfs+ found at offset 0x%llx\n", (unsigned long long) off);
 215
 216                 buf = volume_id_get_buffer(id, off + HFS_SUPERBLOCK_OFFSET, 0x200);
 217                 if (buf == NULL)
 218                         return -1;
 219                 goto checkplus;
 220         }
 221
 222         if (hfs->label_len > 0 && hfs->label_len < 28) {
 223                 volume_id_set_label_raw(id, hfs->label, hfs->label_len);
 224                 volume_id_set_label_string(id, hfs->label, hfs->label_len) ;
 225         }
 226
 227         hfsid_set_uuid(id, hfs->finder_info.id);
 228
 229         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 230         id->type = "hfs";
 231
 232         return 0;
 233
 234 checkplus:
 235         hfsplus = (struct hfsplus_vol_header *) buf;
 236         if (memcmp(hfsplus->signature, "H+", 2) == 0)
 237                 goto hfsplus;
 238         if (memcmp(hfsplus->signature, "HX", 2) == 0)
 239                 goto hfsplus;
 240         return -1;
 241
 242 hfsplus:
 243         hfsid_set_uuid(id, hfsplus->finder_info.id);
 244
 245         blocksize = be32_to_cpu(hfsplus->blocksize);
 246         dbg("blocksize %u\n", blocksize);
 247
 248         memcpy(extents, hfsplus->cat_file.extents, sizeof(extents));
 249         cat_block = be32_to_cpu(extents[0].start_block);
 250         dbg("catalog start block 0x%x\n", cat_block);
 251
 252         buf = volume_id_get_buffer(id, off + (cat_block * blocksize), 0x2000);
 253         if (buf == NULL)
 254                 goto found;
 255
 256         bnode = (struct hfsplus_bheader_record *)
 257                 &buf[sizeof(struct hfsplus_bnode_descriptor)];
 258
 259         leaf_node_head = be32_to_cpu(bnode->leaf_head);
 260         dbg("catalog leaf node 0x%x\n", leaf_node_head);
 261
 262         leaf_node_size = be16_to_cpu(bnode->node_size);
 263         dbg("leaf node size 0x%x\n", leaf_node_size);
 264
 265         leaf_node_count = be32_to_cpu(bnode->leaf_count);
 266         dbg("leaf node count 0x%x\n", leaf_node_count);
 267         if (leaf_node_count == 0)
 268                 goto found;
 269
 270         leaf_block = (leaf_node_head * leaf_node_size) / blocksize;
 271
 272         /* get physical location */
 273         for (ext = 0; ext < HFSPLUS_EXTENT_COUNT; ext++) {
 274                 ext_block_start = be32_to_cpu(extents[ext].start_block);
 275                 ext_block_count = be32_to_cpu(extents[ext].block_count);
 276                 dbg("extent start block 0x%x, count 0x%x\n", ext_block_start, ext_block_count);
 277
 278                 if (ext_block_count == 0)
 279                         goto found;
 280
 281                 /* this is our extent */
 282                 if (leaf_block < ext_block_count)
 283                         break;
 284
 285                 leaf_block -= ext_block_count;
 286         }
 287         if (ext == HFSPLUS_EXTENT_COUNT)
 288                 goto found;
 289         dbg("found block in extent %i\n", ext);
 290
 291         leaf_off = (ext_block_start + leaf_block) * blocksize;
 292
 293         buf = volume_id_get_buffer(id, off + leaf_off, leaf_node_size);
 294         if (buf == NULL)
 295                 goto found;
 296
 297         descr = (struct hfsplus_bnode_descriptor *) buf;
 298         dbg("descriptor type 0x%x\n", descr->type);
 299
 300         record_count = be16_to_cpu(descr->num_recs);
 301         dbg("number of records %u\n", record_count);
 302         if (record_count == 0)
 303                 goto found;
 304
 305         if (descr->type != HFS_NODE_LEAF)
 306                 goto found;
 307
 308         key = (struct hfsplus_catalog_key *)
 309                 &buf[sizeof(struct hfsplus_bnode_descriptor)];
 310
 311         dbg("parent id 0x%x\n", be32_to_cpu(key->parent_id));
 312         if (be32_to_cpu(key->parent_id) != HFSPLUS_POR_CNID)
 313                 goto found;
 314
 315         label_len = be16_to_cpu(key->unicode_len) * 2;
 316         dbg("label unicode16 len %i\n", label_len);
 317         volume_id_set_label_raw(id, key->unicode, label_len);
 318         volume_id_set_label_unicode16(id, key->unicode, BE, label_len);
 319
 320 found:
 321         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 322         id->type = "hfsplus";
 323
 324         return 0;
 325 }