1 /* 2 * openfs.c --- open an ext2 filesystem 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include "config.h" 13 #include <stdio.h> 14 #include <string.h> 15 #if HAVE_UNISTD_H 16 #include <unistd.h> 17 #endif 18 #include <fcntl.h> 19 #include <time.h> 20 #if HAVE_SYS_STAT_H 21 #include <sys/stat.h> 22 #endif 23 #if HAVE_SYS_TYPES_H 24 #include <sys/types.h> 25 #endif 26 #ifdef HAVE_ERRNO_H 27 #include <errno.h> 28 #endif 29 30 #include "ext2_fs.h" 31 32 #include "ext2fs.h" 33 #include "e2image.h" 34 35 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block, 36 dgrp_t i) 37 { 38 int bg; 39 int has_super = 0, group_zero_adjust = 0; 40 blk64_t ret_blk; 41 42 /* 43 * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4 44 * stuff, so adjust for that if we're being asked for group 0. 45 */ 46 if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1) 47 group_zero_adjust = 1; 48 49 if (!ext2fs_has_feature_meta_bg(fs->super) || 50 (i < fs->super->s_first_meta_bg)) 51 return group_block + i + 1 + group_zero_adjust; 52 53 bg = EXT2_DESC_PER_BLOCK(fs->super) * i; 54 if (ext2fs_bg_has_super(fs, bg)) 55 has_super = 1; 56 ret_blk = ext2fs_group_first_block2(fs, bg); 57 /* 58 * If group_block is not the normal value, we're trying to use 59 * the backup group descriptors and superblock --- so use the 60 * alternate location of the second block group in the 61 * metablock group. Ideally we should be testing each bg 62 * descriptor block individually for correctness, but we don't 63 * have the infrastructure in place to do that. 64 */ 65 if (group_block != fs->super->s_first_data_block && 66 ((ret_blk + has_super + fs->super->s_blocks_per_group) < 67 ext2fs_blocks_count(fs->super))) { 68 ret_blk += fs->super->s_blocks_per_group; 69 70 /* 71 * If we're going to jump forward a block group, make sure 72 * that we adjust has_super to account for the next group's 73 * backup superblock (or lack thereof). 74 */ 75 if (ext2fs_bg_has_super(fs, bg + 1)) 76 has_super = 1; 77 else 78 has_super = 0; 79 } 80 return ret_blk + has_super + group_zero_adjust; 81 } 82 83 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) 84 { 85 return ext2fs_descriptor_block_loc2(fs, group_block, i); 86 } 87 88 errcode_t ext2fs_open(const char *name, int flags, int superblock, 89 unsigned int block_size, io_manager manager, 90 ext2_filsys *ret_fs) 91 { 92 return ext2fs_open2(name, 0, flags, superblock, block_size, 93 manager, ret_fs); 94 } 95 96 static void block_sha_map_free_entry(void *data) 97 { 98 free(data); 99 return; 100 } 101 102 /* 103 * Note: if superblock is non-zero, block-size must also be non-zero. 104 * Superblock and block_size can be zero to use the default size. 105 * 106 * Valid flags for ext2fs_open() 107 * 108 * EXT2_FLAG_RW - Open the filesystem for read/write. 109 * EXT2_FLAG_FORCE - Open the filesystem even if some of the 110 * features aren't supported. 111 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device 112 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check. 113 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large 114 * filesystems) 115 */ 116 errcode_t ext2fs_open2(const char *name, const char *io_options, 117 int flags, int superblock, 118 unsigned int block_size, io_manager manager, 119 ext2_filsys *ret_fs) 120 { 121 ext2_filsys fs; 122 errcode_t retval; 123 unsigned long i, first_meta_bg; 124 __u32 features; 125 unsigned int blocks_per_group, io_flags; 126 blk64_t group_block, blk; 127 char *dest, *cp; 128 int group_zero_adjust = 0; 129 unsigned int inode_size; 130 __u64 groups_cnt; 131 #ifdef WORDS_BIGENDIAN 132 unsigned int groups_per_block; 133 struct ext2_group_desc *gdp; 134 int j; 135 #endif 136 char *time_env; 137 int csum_retries = 0; 138 139 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 140 141 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 142 if (retval) 143 return retval; 144 145 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 146 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 147 fs->flags = flags; 148 /* don't overwrite sb backups unless flag is explicitly cleared */ 149 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 150 fs->umask = 022; 151 152 time_env = getenv("E2FSPROGS_FAKE_TIME"); 153 if (time_env) 154 fs->now = strtoul(time_env, NULL, 0); 155 156 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 157 if (retval) 158 goto cleanup; 159 strcpy(fs->device_name, name); 160 cp = strchr(fs->device_name, '?'); 161 if (!io_options && cp) { 162 *cp++ = 0; 163 io_options = cp; 164 } 165 166 io_flags = 0; 167 if (flags & EXT2_FLAG_RW) 168 io_flags |= IO_FLAG_RW; 169 if (flags & EXT2_FLAG_EXCLUSIVE) 170 io_flags |= IO_FLAG_EXCLUSIVE; 171 if (flags & EXT2_FLAG_DIRECT_IO) 172 io_flags |= IO_FLAG_DIRECT_IO; 173 if (flags & EXT2_FLAG_THREADS) 174 io_flags |= IO_FLAG_THREADS; 175 retval = manager->open(fs->device_name, io_flags, &fs->io); 176 if (retval) 177 goto cleanup; 178 if (io_options && 179 (retval = io_channel_set_options(fs->io, io_options))) 180 goto cleanup; 181 fs->image_io = fs->io; 182 fs->io->app_data = fs; 183 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super); 184 if (retval) 185 goto cleanup; 186 if (flags & EXT2_FLAG_IMAGE_FILE) { 187 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 188 &fs->image_header); 189 if (retval) 190 goto cleanup; 191 retval = io_channel_read_blk(fs->io, 0, 192 -(int)sizeof(struct ext2_image_hdr), 193 fs->image_header); 194 if (retval) 195 goto cleanup; 196 if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE) 197 return EXT2_ET_MAGIC_E2IMAGE; 198 superblock = 1; 199 block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize); 200 } 201 202 /* 203 * If the user specifies a specific block # for the 204 * superblock, then he/she must also specify the block size! 205 * Otherwise, read the master superblock located at offset 206 * SUPERBLOCK_OFFSET from the start of the partition. 207 * 208 * Note: we only save a backup copy of the superblock if we 209 * are reading the superblock from the primary superblock location. 210 */ 211 if (superblock) { 212 if (!block_size) { 213 retval = EXT2_ET_INVALID_ARGUMENT; 214 goto cleanup; 215 } 216 io_channel_set_blksize(fs->io, block_size); 217 group_block = superblock; 218 fs->orig_super = 0; 219 } else { 220 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 221 superblock = 1; 222 group_block = 0; 223 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 224 if (retval) 225 goto cleanup; 226 } 227 retry: 228 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 229 fs->super); 230 if (retval) 231 goto cleanup; 232 if (fs->orig_super) 233 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 234 235 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) { 236 retval = 0; 237 if (!ext2fs_verify_csum_type(fs, fs->super)) 238 retval = EXT2_ET_UNKNOWN_CSUM; 239 if (!ext2fs_superblock_csum_verify(fs, fs->super)) { 240 if (csum_retries++ < 3) 241 goto retry; 242 retval = EXT2_ET_SB_CSUM_INVALID; 243 } 244 } 245 246 #ifdef WORDS_BIGENDIAN 247 fs->flags |= EXT2_FLAG_SWAP_BYTES; 248 ext2fs_swap_super(fs->super); 249 #else 250 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 251 retval = EXT2_ET_UNIMPLEMENTED; 252 goto cleanup; 253 } 254 #endif 255 256 if (fs->super->s_magic != EXT2_SUPER_MAGIC) 257 retval = EXT2_ET_BAD_MAGIC; 258 if (retval) 259 goto cleanup; 260 261 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 262 retval = EXT2_ET_REV_TOO_HIGH; 263 goto cleanup; 264 } 265 266 /* 267 * Check for feature set incompatibility 268 */ 269 if (!(flags & EXT2_FLAG_FORCE)) { 270 features = fs->super->s_feature_incompat; 271 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 272 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 273 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT; 274 #endif 275 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 276 retval = EXT2_ET_UNSUPP_FEATURE; 277 goto cleanup; 278 } 279 280 features = fs->super->s_feature_ro_compat; 281 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 282 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 283 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT; 284 #endif 285 if ((flags & EXT2_FLAG_RW) && 286 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 287 retval = EXT2_ET_RO_UNSUPP_FEATURE; 288 goto cleanup; 289 } 290 291 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 292 ext2fs_has_feature_journal_dev(fs->super)) { 293 retval = EXT2_ET_UNSUPP_FEATURE; 294 goto cleanup; 295 } 296 } 297 298 if (fs->super->s_log_block_size > 299 (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) { 300 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 301 goto cleanup; 302 } 303 304 /* 305 * bigalloc requires cluster-aware bitfield operations, which at the 306 * moment means we need EXT2_FLAG_64BITS. 307 */ 308 if (ext2fs_has_feature_bigalloc(fs->super) && 309 !(flags & EXT2_FLAG_64BITS)) { 310 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS; 311 goto cleanup; 312 } 313 314 if (!ext2fs_has_feature_bigalloc(fs->super) && 315 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { 316 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 317 goto cleanup; 318 } 319 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 320 inode_size = EXT2_INODE_SIZE(fs->super); 321 if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) || 322 (inode_size > fs->blocksize) || 323 (inode_size & (inode_size - 1))) { 324 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 325 goto cleanup; 326 } 327 328 /* Enforce the block group descriptor size */ 329 if (ext2fs_has_feature_64bit(fs->super)) { 330 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) { 331 retval = EXT2_ET_BAD_DESC_SIZE; 332 goto cleanup; 333 } 334 } 335 336 fs->cluster_ratio_bits = fs->super->s_log_cluster_size - 337 fs->super->s_log_block_size; 338 if (EXT2_BLOCKS_PER_GROUP(fs->super) != 339 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { 340 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 341 goto cleanup; 342 } 343 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 344 EXT2_INODE_SIZE(fs->super) + 345 EXT2_BLOCK_SIZE(fs->super) - 1) / 346 EXT2_BLOCK_SIZE(fs->super)); 347 if (block_size) { 348 if (block_size != fs->blocksize) { 349 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 350 goto cleanup; 351 } 352 } 353 /* 354 * Set the blocksize to the filesystem's blocksize. 355 */ 356 io_channel_set_blksize(fs->io, fs->blocksize); 357 358 /* 359 * If this is an external journal device, don't try to read 360 * the group descriptors, because they're not there. 361 */ 362 if (ext2fs_has_feature_journal_dev(fs->super)) { 363 fs->group_desc_count = 0; 364 *ret_fs = fs; 365 return 0; 366 } 367 368 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 369 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 370 goto cleanup; 371 } 372 /* Precompute the FS UUID to seed other checksums */ 373 ext2fs_init_csum_seed(fs); 374 375 /* 376 * Read group descriptors 377 */ 378 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 379 if (blocks_per_group == 0 || 380 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 381 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 382 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 383 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { 384 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 385 goto cleanup; 386 } 387 groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - 388 fs->super->s_first_data_block, 389 blocks_per_group); 390 if (groups_cnt >> 32) { 391 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 392 goto cleanup; 393 } 394 fs->group_desc_count = groups_cnt; 395 if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) && 396 (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 397 fs->super->s_inodes_count) { 398 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 399 goto cleanup; 400 } 401 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 402 EXT2_DESC_PER_BLOCK(fs->super)); 403 if (flags & EXT2_FLAG_SUPER_ONLY) 404 goto skip_read_bg; 405 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 406 &fs->group_desc); 407 if (retval) 408 goto cleanup; 409 if (!group_block) 410 group_block = fs->super->s_first_data_block; 411 /* 412 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders 413 * so we must increment block numbers to any group 0 items. 414 * 415 * However, we cannot touch group_block directly because in the meta_bg 416 * case, the ext2fs_descriptor_block_loc2() function will interpret 417 * group_block != s_first_data_block to mean that we want to access the 418 * backup group descriptors. This is not what we want if the caller 419 * set superblock == 0 (i.e. auto-detect the superblock), which is 420 * what's going on here. 421 */ 422 if (group_block == 0 && fs->blocksize == 1024) 423 group_zero_adjust = 1; 424 dest = (char *) fs->group_desc; 425 #ifdef WORDS_BIGENDIAN 426 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 427 #endif 428 if (ext2fs_has_feature_meta_bg(fs->super) && 429 !(flags & EXT2_FLAG_IMAGE_FILE)) { 430 first_meta_bg = fs->super->s_first_meta_bg; 431 if (first_meta_bg > fs->desc_blocks) 432 first_meta_bg = fs->desc_blocks; 433 } else 434 first_meta_bg = fs->desc_blocks; 435 if (first_meta_bg) { 436 retval = io_channel_read_blk(fs->io, group_block + 437 group_zero_adjust + 1, 438 first_meta_bg, dest); 439 if (retval) 440 goto cleanup; 441 #ifdef WORDS_BIGENDIAN 442 gdp = (struct ext2_group_desc *) dest; 443 for (j=0; j < groups_per_block*first_meta_bg; j++) { 444 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 445 if (gdp) 446 ext2fs_swap_group_desc2(fs, gdp); 447 } 448 #endif 449 dest += fs->blocksize*first_meta_bg; 450 } 451 452 for (i = first_meta_bg ; i < fs->desc_blocks; i++) { 453 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 454 io_channel_cache_readahead(fs->io, blk, 1); 455 } 456 457 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 458 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 459 retval = io_channel_read_blk64(fs->io, blk, 1, dest); 460 if (retval) 461 goto cleanup; 462 #ifdef WORDS_BIGENDIAN 463 for (j=0; j < groups_per_block; j++) { 464 gdp = ext2fs_group_desc(fs, fs->group_desc, 465 i * groups_per_block + j); 466 if (gdp) 467 ext2fs_swap_group_desc2(fs, gdp); 468 } 469 #endif 470 dest += fs->blocksize; 471 } 472 473 fs->stride = fs->super->s_raid_stride; 474 475 /* 476 * If recovery is from backup superblock, Clear _UNININT flags & 477 * reset bg_itable_unused to zero 478 */ 479 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) { 480 dgrp_t group; 481 482 for (group = 0; group < fs->group_desc_count; group++) { 483 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); 484 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); 485 ext2fs_bg_itable_unused_set(fs, group, 0); 486 /* The checksum will be reset later, but fix it here 487 * anyway to avoid printing a lot of spurious errors. */ 488 ext2fs_group_desc_csum_set(fs, group); 489 } 490 if (fs->flags & EXT2_FLAG_RW) 491 ext2fs_mark_super_dirty(fs); 492 } 493 skip_read_bg: 494 if (ext2fs_has_feature_mmp(fs->super) && 495 !(flags & EXT2_FLAG_SKIP_MMP) && 496 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) { 497 retval = ext2fs_mmp_start(fs); 498 if (retval) { 499 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */ 500 ext2fs_mmp_stop(fs); 501 goto cleanup; 502 } 503 } 504 505 if (fs->flags & EXT2_FLAG_SHARE_DUP) { 506 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash, 507 block_sha_map_free_entry, 4096); 508 if (!fs->block_sha_map) { 509 retval = EXT2_ET_NO_MEMORY; 510 goto cleanup; 511 } 512 ext2fs_set_feature_shared_blocks(fs->super); 513 } 514 515 if (ext2fs_has_feature_casefold(fs->super)) 516 fs->encoding = ext2fs_load_nls_table(fs->super->s_encoding); 517 518 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 519 *ret_fs = fs; 520 521 return 0; 522 cleanup: 523 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) { 524 ext2fs_free(fs); 525 fs = NULL; 526 } 527 *ret_fs = fs; 528 return retval; 529 } 530 531 /* 532 * Set/get the filesystem data I/O channel. 533 * 534 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 535 */ 536 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 537 { 538 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 539 return EXT2_ET_NOT_IMAGE_FILE; 540 if (old_io) { 541 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 542 } 543 return 0; 544 } 545 546 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 547 { 548 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 549 return EXT2_ET_NOT_IMAGE_FILE; 550 fs->io = new_io ? new_io : fs->image_io; 551 return 0; 552 } 553 554 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 555 { 556 errcode_t err; 557 558 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 559 return EXT2_ET_NOT_IMAGE_FILE; 560 err = io_channel_set_blksize(new_io, fs->blocksize); 561 if (err) 562 return err; 563 if ((new_io == fs->image_io) || (new_io == fs->io)) 564 return 0; 565 if ((fs->image_io != fs->io) && 566 fs->image_io) 567 io_channel_close(fs->image_io); 568 if (fs->io) 569 io_channel_close(fs->io); 570 fs->io = fs->image_io = new_io; 571 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 572 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 573 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 574 return 0; 575 }