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