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 #ifdef WORDS_BIGENDIAN 131 unsigned int groups_per_block; 132 struct ext2_group_desc *gdp; 133 int j; 134 #endif 135 char *time_env; 136 137 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 138 139 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 140 if (retval) 141 return retval; 142 143 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 144 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 145 fs->flags = flags; 146 /* don't overwrite sb backups unless flag is explicitly cleared */ 147 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 148 fs->umask = 022; 149 150 time_env = getenv("E2FSPROGS_FAKE_TIME"); 151 if (time_env) 152 fs->now = strtoul(time_env, NULL, 0); 153 154 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 155 if (retval) 156 goto cleanup; 157 strcpy(fs->device_name, name); 158 cp = strchr(fs->device_name, '?'); 159 if (!io_options && cp) { 160 *cp++ = 0; 161 io_options = cp; 162 } 163 164 io_flags = 0; 165 if (flags & EXT2_FLAG_RW) 166 io_flags |= IO_FLAG_RW; 167 if (flags & EXT2_FLAG_EXCLUSIVE) 168 io_flags |= IO_FLAG_EXCLUSIVE; 169 if (flags & EXT2_FLAG_DIRECT_IO) 170 io_flags |= IO_FLAG_DIRECT_IO; 171 retval = manager->open(fs->device_name, io_flags, &fs->io); 172 if (retval) 173 goto cleanup; 174 if (io_options && 175 (retval = io_channel_set_options(fs->io, io_options))) 176 goto cleanup; 177 fs->image_io = fs->io; 178 fs->io->app_data = fs; 179 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super); 180 if (retval) 181 goto cleanup; 182 if (flags & EXT2_FLAG_IMAGE_FILE) { 183 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 184 &fs->image_header); 185 if (retval) 186 goto cleanup; 187 retval = io_channel_read_blk(fs->io, 0, 188 -(int)sizeof(struct ext2_image_hdr), 189 fs->image_header); 190 if (retval) 191 goto cleanup; 192 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 193 return EXT2_ET_MAGIC_E2IMAGE; 194 superblock = 1; 195 block_size = fs->image_header->fs_blocksize; 196 } 197 198 /* 199 * If the user specifies a specific block # for the 200 * superblock, then he/she must also specify the block size! 201 * Otherwise, read the master superblock located at offset 202 * SUPERBLOCK_OFFSET from the start of the partition. 203 * 204 * Note: we only save a backup copy of the superblock if we 205 * are reading the superblock from the primary superblock location. 206 */ 207 if (superblock) { 208 if (!block_size) { 209 retval = EXT2_ET_INVALID_ARGUMENT; 210 goto cleanup; 211 } 212 io_channel_set_blksize(fs->io, block_size); 213 group_block = superblock; 214 fs->orig_super = 0; 215 } else { 216 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 217 superblock = 1; 218 group_block = 0; 219 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 220 if (retval) 221 goto cleanup; 222 } 223 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 224 fs->super); 225 if (retval) 226 goto cleanup; 227 if (fs->orig_super) 228 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 229 230 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) { 231 retval = 0; 232 if (!ext2fs_verify_csum_type(fs, fs->super)) 233 retval = EXT2_ET_UNKNOWN_CSUM; 234 if (!ext2fs_superblock_csum_verify(fs, fs->super)) 235 retval = EXT2_ET_SB_CSUM_INVALID; 236 } 237 238 #ifdef WORDS_BIGENDIAN 239 fs->flags |= EXT2_FLAG_SWAP_BYTES; 240 ext2fs_swap_super(fs->super); 241 #else 242 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 243 retval = EXT2_ET_UNIMPLEMENTED; 244 goto cleanup; 245 } 246 #endif 247 248 if (fs->super->s_magic != EXT2_SUPER_MAGIC) 249 retval = EXT2_ET_BAD_MAGIC; 250 if (retval) 251 goto cleanup; 252 253 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 254 retval = EXT2_ET_REV_TOO_HIGH; 255 goto cleanup; 256 } 257 258 /* 259 * Check for feature set incompatibility 260 */ 261 if (!(flags & EXT2_FLAG_FORCE)) { 262 features = fs->super->s_feature_incompat; 263 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 264 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 265 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT; 266 #endif 267 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 268 retval = EXT2_ET_UNSUPP_FEATURE; 269 goto cleanup; 270 } 271 272 features = fs->super->s_feature_ro_compat; 273 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 274 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 275 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT; 276 #endif 277 if ((flags & EXT2_FLAG_RW) && 278 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 279 retval = EXT2_ET_RO_UNSUPP_FEATURE; 280 goto cleanup; 281 } 282 283 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 284 ext2fs_has_feature_journal_dev(fs->super)) { 285 retval = EXT2_ET_UNSUPP_FEATURE; 286 goto cleanup; 287 } 288 } 289 290 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) > 291 EXT2_MAX_BLOCK_LOG_SIZE) { 292 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 293 goto cleanup; 294 } 295 296 /* 297 * bigalloc requires cluster-aware bitfield operations, which at the 298 * moment means we need EXT2_FLAG_64BITS. 299 */ 300 if (ext2fs_has_feature_bigalloc(fs->super) && 301 !(flags & EXT2_FLAG_64BITS)) { 302 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS; 303 goto cleanup; 304 } 305 306 if (!ext2fs_has_feature_bigalloc(fs->super) && 307 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { 308 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 309 goto cleanup; 310 } 311 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 312 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) { 313 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 314 goto cleanup; 315 } 316 317 /* Enforce the block group descriptor size */ 318 if (ext2fs_has_feature_64bit(fs->super)) { 319 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) { 320 retval = EXT2_ET_BAD_DESC_SIZE; 321 goto cleanup; 322 } 323 } else { 324 if (fs->super->s_desc_size && 325 fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) { 326 retval = EXT2_ET_BAD_DESC_SIZE; 327 goto cleanup; 328 } 329 } 330 331 fs->cluster_ratio_bits = fs->super->s_log_cluster_size - 332 fs->super->s_log_block_size; 333 if (EXT2_BLOCKS_PER_GROUP(fs->super) != 334 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { 335 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 336 goto cleanup; 337 } 338 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 339 EXT2_INODE_SIZE(fs->super) + 340 EXT2_BLOCK_SIZE(fs->super) - 1) / 341 EXT2_BLOCK_SIZE(fs->super)); 342 if (block_size) { 343 if (block_size != fs->blocksize) { 344 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 345 goto cleanup; 346 } 347 } 348 /* 349 * Set the blocksize to the filesystem's blocksize. 350 */ 351 io_channel_set_blksize(fs->io, fs->blocksize); 352 353 /* 354 * If this is an external journal device, don't try to read 355 * the group descriptors, because they're not there. 356 */ 357 if (ext2fs_has_feature_journal_dev(fs->super)) { 358 fs->group_desc_count = 0; 359 *ret_fs = fs; 360 return 0; 361 } 362 363 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 364 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 365 goto cleanup; 366 } 367 /* Precompute the FS UUID to seed other checksums */ 368 ext2fs_init_csum_seed(fs); 369 370 /* 371 * Read group descriptors 372 */ 373 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 374 if (blocks_per_group == 0 || 375 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 376 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 377 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 378 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { 379 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 380 goto cleanup; 381 } 382 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - 383 fs->super->s_first_data_block, 384 blocks_per_group); 385 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 386 fs->super->s_inodes_count) { 387 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 388 goto cleanup; 389 } 390 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 391 EXT2_DESC_PER_BLOCK(fs->super)); 392 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 393 &fs->group_desc); 394 if (retval) 395 goto cleanup; 396 if (!group_block) 397 group_block = fs->super->s_first_data_block; 398 /* 399 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders 400 * so we must increment block numbers to any group 0 items. 401 * 402 * However, we cannot touch group_block directly because in the meta_bg 403 * case, the ext2fs_descriptor_block_loc2() function will interpret 404 * group_block != s_first_data_block to mean that we want to access the 405 * backup group descriptors. This is not what we want if the caller 406 * set superblock == 0 (i.e. auto-detect the superblock), which is 407 * what's going on here. 408 */ 409 if (group_block == 0 && fs->blocksize == 1024) 410 group_zero_adjust = 1; 411 dest = (char *) fs->group_desc; 412 #ifdef WORDS_BIGENDIAN 413 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 414 #endif 415 if (ext2fs_has_feature_meta_bg(fs->super)) { 416 first_meta_bg = fs->super->s_first_meta_bg; 417 if (first_meta_bg > fs->desc_blocks) 418 first_meta_bg = fs->desc_blocks; 419 } else 420 first_meta_bg = fs->desc_blocks; 421 if (first_meta_bg) { 422 retval = io_channel_read_blk(fs->io, group_block + 423 group_zero_adjust + 1, 424 first_meta_bg, dest); 425 if (retval) 426 goto cleanup; 427 #ifdef WORDS_BIGENDIAN 428 gdp = (struct ext2_group_desc *) dest; 429 for (j=0; j < groups_per_block*first_meta_bg; j++) { 430 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 431 ext2fs_swap_group_desc2(fs, gdp); 432 } 433 #endif 434 dest += fs->blocksize*first_meta_bg; 435 } 436 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 437 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 438 retval = io_channel_read_blk64(fs->io, blk, 1, dest); 439 if (retval) 440 goto cleanup; 441 #ifdef WORDS_BIGENDIAN 442 for (j=0; j < groups_per_block; j++) { 443 gdp = ext2fs_group_desc(fs, fs->group_desc, 444 i * groups_per_block + j); 445 ext2fs_swap_group_desc2(fs, gdp); 446 } 447 #endif 448 dest += fs->blocksize; 449 } 450 451 fs->stride = fs->super->s_raid_stride; 452 453 /* 454 * If recovery is from backup superblock, Clear _UNININT flags & 455 * reset bg_itable_unused to zero 456 */ 457 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) { 458 dgrp_t group; 459 460 for (group = 0; group < fs->group_desc_count; group++) { 461 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); 462 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); 463 ext2fs_bg_itable_unused_set(fs, group, 0); 464 /* The checksum will be reset later, but fix it here 465 * anyway to avoid printing a lot of spurious errors. */ 466 ext2fs_group_desc_csum_set(fs, group); 467 } 468 if (fs->flags & EXT2_FLAG_RW) 469 ext2fs_mark_super_dirty(fs); 470 } 471 472 if (ext2fs_has_feature_mmp(fs->super) && 473 !(flags & EXT2_FLAG_SKIP_MMP) && 474 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) { 475 retval = ext2fs_mmp_start(fs); 476 if (retval) { 477 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */ 478 ext2fs_mmp_stop(fs); 479 goto cleanup; 480 } 481 } 482 483 if (fs->flags & EXT2_FLAG_SHARE_DUP) { 484 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash, 485 block_sha_map_free_entry, 4096); 486 if (!fs->block_sha_map) { 487 retval = EXT2_ET_NO_MEMORY; 488 goto cleanup; 489 } 490 ext2fs_set_feature_shared_blocks(fs->super); 491 } 492 493 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 494 *ret_fs = fs; 495 496 return 0; 497 cleanup: 498 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) { 499 ext2fs_free(fs); 500 fs = NULL; 501 } 502 *ret_fs = fs; 503 return retval; 504 } 505 506 /* 507 * Set/get the filesystem data I/O channel. 508 * 509 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 510 */ 511 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 512 { 513 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 514 return EXT2_ET_NOT_IMAGE_FILE; 515 if (old_io) { 516 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 517 } 518 return 0; 519 } 520 521 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 522 { 523 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 524 return EXT2_ET_NOT_IMAGE_FILE; 525 fs->io = new_io ? new_io : fs->image_io; 526 return 0; 527 } 528 529 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 530 { 531 errcode_t err; 532 533 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 534 return EXT2_ET_NOT_IMAGE_FILE; 535 err = io_channel_set_blksize(new_io, fs->blocksize); 536 if (err) 537 return err; 538 if ((new_io == fs->image_io) || (new_io == fs->io)) 539 return 0; 540 if ((fs->image_io != fs->io) && 541 fs->image_io) 542 io_channel_close(fs->image_io); 543 if (fs->io) 544 io_channel_close(fs->io); 545 fs->io = fs->image_io = new_io; 546 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 547 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 548 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 549 return 0; 550 } 551
