1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "ext4_utils.h" 18 #include "uuid.h" 19 #include "allocate.h" 20 #include "indirect.h" 21 #include "extent.h" 22 23 #include <sparse/sparse.h> 24 25 #include <fcntl.h> 26 #include <inttypes.h> 27 #include <sys/stat.h> 28 #include <sys/types.h> 29 #include <stddef.h> 30 #include <string.h> 31 32 #include <arpa/inet.h> 33 #include <sys/ioctl.h> 34 35 #if defined(__linux__) 36 #include <linux/fs.h> 37 #elif defined(__APPLE__) && defined(__MACH__) 38 #include <sys/disk.h> 39 #endif 40 41 int force = 0; 42 struct fs_info info; 43 struct fs_aux_info aux_info; 44 struct sparse_file *ext4_sparse_file; 45 46 jmp_buf setjmp_env; 47 48 /* returns 1 if a is a power of b */ 49 static int is_power_of(int a, int b) 50 { 51 while (a > b) { 52 if (a % b) 53 return 0; 54 a /= b; 55 } 56 57 return (a == b) ? 1 : 0; 58 } 59 60 int bitmap_get_bit(u8 *bitmap, u32 bit) 61 { 62 if (bitmap[bit / 8] & (1 << (bit % 8))) 63 return 1; 64 65 return 0; 66 } 67 68 void bitmap_clear_bit(u8 *bitmap, u32 bit) 69 { 70 bitmap[bit / 8] &= ~(1 << (bit % 8)); 71 72 return; 73 } 74 75 /* Returns 1 if the bg contains a backup superblock. On filesystems with 76 the sparse_super feature, only block groups 0, 1, and powers of 3, 5, 77 and 7 have backup superblocks. Otherwise, all block groups have backup 78 superblocks */ 79 int ext4_bg_has_super_block(int bg) 80 { 81 /* Without sparse_super, every block group has a superblock */ 82 if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) 83 return 1; 84 85 if (bg == 0 || bg == 1) 86 return 1; 87 88 if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7)) 89 return 1; 90 91 return 0; 92 } 93 94 /* Function to read the primary superblock */ 95 void read_sb(int fd, struct ext4_super_block *sb) 96 { 97 off_t ret; 98 99 ret = lseek(fd, 1024, SEEK_SET); 100 if (ret < 0) 101 critical_error_errno("failed to seek to superblock"); 102 103 ret = read(fd, sb, sizeof(*sb)); 104 if (ret < 0) 105 critical_error_errno("failed to read superblock"); 106 if (ret != sizeof(*sb)) 107 critical_error("failed to read all of superblock"); 108 } 109 110 /* Function to write a primary or backup superblock at a given offset */ 111 void write_sb(int fd, unsigned long long offset, struct ext4_super_block *sb) 112 { 113 off_t ret; 114 115 ret = lseek(fd, offset, SEEK_SET); 116 if (ret < 0) 117 critical_error_errno("failed to seek to superblock"); 118 119 ret = write(fd, sb, sizeof(*sb)); 120 if (ret < 0) 121 critical_error_errno("failed to write superblock"); 122 if (ret != sizeof(*sb)) 123 critical_error("failed to write all of superblock"); 124 } 125 126 /* Write the filesystem image to a file */ 127 void write_ext4_image(int fd, int gz, int sparse, int crc) 128 { 129 sparse_file_write(ext4_sparse_file, fd, gz, sparse, crc); 130 } 131 132 /* Compute the rest of the parameters of the filesystem from the basic info */ 133 void ext4_create_fs_aux_info() 134 { 135 aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1; 136 aux_info.len_blocks = info.len / info.block_size; 137 aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size, 138 info.block_size); 139 aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block, 140 info.blocks_per_group); 141 aux_info.blocks_per_ind = info.block_size / sizeof(u32); 142 aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind; 143 aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind; 144 145 aux_info.bg_desc_blocks = 146 DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc), 147 info.block_size); 148 149 aux_info.default_i_flags = EXT4_NOATIME_FL; 150 151 u32 last_group_size = aux_info.len_blocks % info.blocks_per_group; 152 u32 last_header_size = 2 + aux_info.inode_table_blocks; 153 if (ext4_bg_has_super_block(aux_info.groups - 1)) 154 last_header_size += 1 + aux_info.bg_desc_blocks + 155 info.bg_desc_reserve_blocks; 156 if (last_group_size > 0 && last_group_size < last_header_size) { 157 aux_info.groups--; 158 aux_info.len_blocks -= last_group_size; 159 } 160 161 aux_info.sb = calloc(info.block_size, 1); 162 /* Alloc an array to hold the pointers to the backup superblocks */ 163 aux_info.backup_sb = calloc(aux_info.groups, sizeof(char *)); 164 165 if (!aux_info.sb) 166 critical_error_errno("calloc"); 167 168 aux_info.bg_desc = calloc(info.block_size, aux_info.bg_desc_blocks); 169 if (!aux_info.bg_desc) 170 critical_error_errno("calloc"); 171 aux_info.xattrs = NULL; 172 } 173 174 void ext4_free_fs_aux_info() 175 { 176 unsigned int i; 177 178 for (i=0; i<aux_info.groups; i++) { 179 if (aux_info.backup_sb[i]) 180 free(aux_info.backup_sb[i]); 181 } 182 free(aux_info.sb); 183 free(aux_info.bg_desc); 184 } 185 186 /* Fill in the superblock memory buffer based on the filesystem parameters */ 187 void ext4_fill_in_sb() 188 { 189 unsigned int i; 190 struct ext4_super_block *sb = aux_info.sb; 191 192 sb->s_inodes_count = info.inodes_per_group * aux_info.groups; 193 sb->s_blocks_count_lo = aux_info.len_blocks; 194 sb->s_r_blocks_count_lo = (aux_info.len_blocks / 100) * info.reserve_pcnt; 195 sb->s_free_blocks_count_lo = 0; 196 sb->s_free_inodes_count = 0; 197 sb->s_first_data_block = aux_info.first_data_block; 198 sb->s_log_block_size = log_2(info.block_size / 1024); 199 sb->s_obso_log_frag_size = log_2(info.block_size / 1024); 200 sb->s_blocks_per_group = info.blocks_per_group; 201 sb->s_obso_frags_per_group = info.blocks_per_group; 202 sb->s_inodes_per_group = info.inodes_per_group; 203 sb->s_mtime = 0; 204 sb->s_wtime = 0; 205 sb->s_mnt_count = 0; 206 sb->s_max_mnt_count = 0xFFFF; 207 sb->s_magic = EXT4_SUPER_MAGIC; 208 sb->s_state = EXT4_VALID_FS; 209 sb->s_errors = EXT4_ERRORS_RO; 210 sb->s_minor_rev_level = 0; 211 sb->s_lastcheck = 0; 212 sb->s_checkinterval = 0; 213 sb->s_creator_os = EXT4_OS_LINUX; 214 sb->s_rev_level = EXT4_DYNAMIC_REV; 215 sb->s_def_resuid = EXT4_DEF_RESUID; 216 sb->s_def_resgid = EXT4_DEF_RESGID; 217 218 sb->s_first_ino = EXT4_GOOD_OLD_FIRST_INO; 219 sb->s_inode_size = info.inode_size; 220 sb->s_block_group_nr = 0; 221 sb->s_feature_compat = info.feat_compat; 222 sb->s_feature_incompat = info.feat_incompat; 223 sb->s_feature_ro_compat = info.feat_ro_compat; 224 generate_uuid("extandroid/make_ext4fs", info.label, sb->s_uuid); 225 memset(sb->s_volume_name, 0, sizeof(sb->s_volume_name)); 226 strncpy(sb->s_volume_name, info.label, sizeof(sb->s_volume_name)); 227 memset(sb->s_last_mounted, 0, sizeof(sb->s_last_mounted)); 228 sb->s_algorithm_usage_bitmap = 0; 229 230 sb->s_reserved_gdt_blocks = info.bg_desc_reserve_blocks; 231 sb->s_prealloc_blocks = 0; 232 sb->s_prealloc_dir_blocks = 0; 233 234 //memcpy(sb->s_journal_uuid, sb->s_uuid, sizeof(sb->s_journal_uuid)); 235 if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL) 236 sb->s_journal_inum = EXT4_JOURNAL_INO; 237 sb->s_journal_dev = 0; 238 sb->s_last_orphan = 0; 239 sb->s_hash_seed[0] = 0; /* FIXME */ 240 sb->s_def_hash_version = DX_HASH_TEA; 241 sb->s_reserved_char_pad = EXT4_JNL_BACKUP_BLOCKS; 242 sb->s_desc_size = sizeof(struct ext2_group_desc); 243 sb->s_default_mount_opts = 0; /* FIXME */ 244 sb->s_first_meta_bg = 0; 245 sb->s_mkfs_time = 0; 246 //sb->s_jnl_blocks[17]; /* FIXME */ 247 248 sb->s_blocks_count_hi = aux_info.len_blocks >> 32; 249 sb->s_r_blocks_count_hi = 0; 250 sb->s_free_blocks_count_hi = 0; 251 sb->s_min_extra_isize = sizeof(struct ext4_inode) - 252 EXT4_GOOD_OLD_INODE_SIZE; 253 sb->s_want_extra_isize = sizeof(struct ext4_inode) - 254 EXT4_GOOD_OLD_INODE_SIZE; 255 sb->s_flags = 2; 256 sb->s_raid_stride = 0; 257 sb->s_mmp_interval = 0; 258 sb->s_mmp_block = 0; 259 sb->s_raid_stripe_width = 0; 260 sb->s_log_groups_per_flex = 0; 261 sb->s_kbytes_written = 0; 262 263 for (i = 0; i < aux_info.groups; i++) { 264 u64 group_start_block = aux_info.first_data_block + i * 265 info.blocks_per_group; 266 u32 header_size = 0; 267 if (ext4_bg_has_super_block(i)) { 268 if (i != 0) { 269 aux_info.backup_sb[i] = calloc(info.block_size, 1); 270 memcpy(aux_info.backup_sb[i], sb, info.block_size); 271 /* Update the block group nr of this backup superblock */ 272 aux_info.backup_sb[i]->s_block_group_nr = i; 273 sparse_file_add_data(ext4_sparse_file, aux_info.backup_sb[i], 274 info.block_size, group_start_block); 275 } 276 sparse_file_add_data(ext4_sparse_file, aux_info.bg_desc, 277 aux_info.bg_desc_blocks * info.block_size, 278 group_start_block + 1); 279 header_size = 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks; 280 } 281 282 aux_info.bg_desc[i].bg_block_bitmap = group_start_block + header_size; 283 aux_info.bg_desc[i].bg_inode_bitmap = group_start_block + header_size + 1; 284 aux_info.bg_desc[i].bg_inode_table = group_start_block + header_size + 2; 285 286 aux_info.bg_desc[i].bg_free_blocks_count = sb->s_blocks_per_group; 287 aux_info.bg_desc[i].bg_free_inodes_count = sb->s_inodes_per_group; 288 aux_info.bg_desc[i].bg_used_dirs_count = 0; 289 } 290 } 291 292 void ext4_queue_sb(void) 293 { 294 /* The write_data* functions expect only block aligned calls. 295 * This is not an issue, except when we write out the super 296 * block on a system with a block size > 1K. So, we need to 297 * deal with that here. 298 */ 299 if (info.block_size > 1024) { 300 u8 *buf = calloc(info.block_size, 1); 301 memcpy(buf + 1024, (u8*)aux_info.sb, 1024); 302 sparse_file_add_data(ext4_sparse_file, buf, info.block_size, 0); 303 } else { 304 sparse_file_add_data(ext4_sparse_file, aux_info.sb, 1024, 1); 305 } 306 } 307 308 void ext4_parse_sb_info(struct ext4_super_block *sb) 309 { 310 if (sb->s_magic != EXT4_SUPER_MAGIC) 311 error("superblock magic incorrect"); 312 313 if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS) 314 error("filesystem state not valid"); 315 316 ext4_parse_sb(sb, &info); 317 318 ext4_create_fs_aux_info(); 319 320 memcpy(aux_info.sb, sb, sizeof(*sb)); 321 322 if (aux_info.first_data_block != sb->s_first_data_block) 323 critical_error("first data block does not match"); 324 } 325 326 void ext4_create_resize_inode() 327 { 328 struct block_allocation *reserve_inode_alloc = create_allocation(); 329 u32 reserve_inode_len = 0; 330 unsigned int i; 331 332 struct ext4_inode *inode = get_inode(EXT4_RESIZE_INO); 333 if (inode == NULL) { 334 error("failed to get resize inode"); 335 return; 336 } 337 338 for (i = 0; i < aux_info.groups; i++) { 339 if (ext4_bg_has_super_block(i)) { 340 u64 group_start_block = aux_info.first_data_block + i * 341 info.blocks_per_group; 342 u32 reserved_block_start = group_start_block + 1 + 343 aux_info.bg_desc_blocks; 344 u32 reserved_block_len = info.bg_desc_reserve_blocks; 345 append_region(reserve_inode_alloc, reserved_block_start, 346 reserved_block_len, i); 347 reserve_inode_len += reserved_block_len; 348 } 349 } 350 351 inode_attach_resize(inode, reserve_inode_alloc); 352 353 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR; 354 inode->i_links_count = 1; 355 356 free_alloc(reserve_inode_alloc); 357 } 358 359 /* Allocate the blocks to hold a journal inode and connect them to the 360 reserved journal inode */ 361 void ext4_create_journal_inode() 362 { 363 struct ext4_inode *inode = get_inode(EXT4_JOURNAL_INO); 364 if (inode == NULL) { 365 error("failed to get journal inode"); 366 return; 367 } 368 369 u8 *journal_data = inode_allocate_data_extents(inode, 370 info.journal_blocks * info.block_size, 371 info.journal_blocks * info.block_size); 372 if (!journal_data) { 373 error("failed to allocate extents for journal data"); 374 return; 375 } 376 377 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR; 378 inode->i_links_count = 1; 379 380 journal_superblock_t *jsb = (journal_superblock_t *)journal_data; 381 jsb->s_header.h_magic = htonl(JBD2_MAGIC_NUMBER); 382 jsb->s_header.h_blocktype = htonl(JBD2_SUPERBLOCK_V2); 383 jsb->s_blocksize = htonl(info.block_size); 384 jsb->s_maxlen = htonl(info.journal_blocks); 385 jsb->s_nr_users = htonl(1); 386 jsb->s_first = htonl(1); 387 jsb->s_sequence = htonl(1); 388 389 memcpy(aux_info.sb->s_jnl_blocks, &inode->i_block, sizeof(inode->i_block)); 390 } 391 392 /* Update the number of free blocks and inodes in the filesystem and in each 393 block group */ 394 void ext4_update_free() 395 { 396 u32 i; 397 398 for (i = 0; i < aux_info.groups; i++) { 399 u32 bg_free_blocks = get_free_blocks(i); 400 u32 bg_free_inodes = get_free_inodes(i); 401 u16 crc; 402 403 aux_info.bg_desc[i].bg_free_blocks_count = bg_free_blocks; 404 aux_info.sb->s_free_blocks_count_lo += bg_free_blocks; 405 406 aux_info.bg_desc[i].bg_free_inodes_count = bg_free_inodes; 407 aux_info.sb->s_free_inodes_count += bg_free_inodes; 408 409 aux_info.bg_desc[i].bg_used_dirs_count += get_directories(i); 410 411 aux_info.bg_desc[i].bg_flags = get_bg_flags(i); 412 413 crc = ext4_crc16(~0, aux_info.sb->s_uuid, sizeof(aux_info.sb->s_uuid)); 414 crc = ext4_crc16(crc, &i, sizeof(i)); 415 crc = ext4_crc16(crc, &aux_info.bg_desc[i], offsetof(struct ext2_group_desc, bg_checksum)); 416 aux_info.bg_desc[i].bg_checksum = crc; 417 } 418 } 419 420 u64 get_block_device_size(int fd) 421 { 422 u64 size = 0; 423 int ret; 424 425 #if defined(__linux__) 426 ret = ioctl(fd, BLKGETSIZE64, &size); 427 #elif defined(__APPLE__) && defined(__MACH__) 428 ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size); 429 #else 430 close(fd); 431 return 0; 432 #endif 433 434 if (ret) 435 return 0; 436 437 return size; 438 } 439 440 int is_block_device_fd(int fd) 441 { 442 struct stat st; 443 int ret = fstat(fd, &st); 444 if (ret < 0) 445 return 0; 446 447 return S_ISBLK(st.st_mode); 448 } 449 450 u64 get_file_size(int fd) 451 { 452 struct stat buf; 453 int ret; 454 u64 reserve_len = 0; 455 s64 computed_size; 456 457 ret = fstat(fd, &buf); 458 if (ret) 459 return 0; 460 461 if (info.len < 0) 462 reserve_len = -info.len; 463 464 if (S_ISREG(buf.st_mode)) 465 computed_size = buf.st_size - reserve_len; 466 else if (S_ISBLK(buf.st_mode)) 467 computed_size = get_block_device_size(fd) - reserve_len; 468 else 469 computed_size = 0; 470 471 if (computed_size < 0) { 472 warn("Computed filesystem size less than 0"); 473 computed_size = 0; 474 } 475 476 return computed_size; 477 } 478 479 u64 parse_num(const char *arg) 480 { 481 char *endptr; 482 u64 num = strtoull(arg, &endptr, 10); 483 if (*endptr == 'k' || *endptr == 'K') 484 num *= 1024LL; 485 else if (*endptr == 'm' || *endptr == 'M') 486 num *= 1024LL * 1024LL; 487 else if (*endptr == 'g' || *endptr == 'G') 488 num *= 1024LL * 1024LL * 1024LL; 489 490 return num; 491 } 492 493 int read_ext(int fd, int verbose) 494 { 495 off_t ret; 496 struct ext4_super_block sb; 497 498 read_sb(fd, &sb); 499 500 ext4_parse_sb_info(&sb); 501 502 ret = lseek(fd, info.len, SEEK_SET); 503 if (ret < 0) 504 critical_error_errno("failed to seek to end of input image"); 505 506 ret = lseek(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET); 507 if (ret < 0) 508 critical_error_errno("failed to seek to block group descriptors"); 509 510 ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks); 511 if (ret < 0) 512 critical_error_errno("failed to read block group descriptors"); 513 if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks) 514 critical_error("failed to read all of block group descriptors"); 515 516 if (verbose) { 517 printf("Found filesystem with parameters:\n"); 518 printf(" Size: %"PRIu64"\n", info.len); 519 printf(" Block size: %d\n", info.block_size); 520 printf(" Blocks per group: %d\n", info.blocks_per_group); 521 printf(" Inodes per group: %d\n", info.inodes_per_group); 522 printf(" Inode size: %d\n", info.inode_size); 523 printf(" Label: %s\n", info.label); 524 printf(" Blocks: %"PRIu64"\n", aux_info.len_blocks); 525 printf(" Block groups: %d\n", aux_info.groups); 526 printf(" Reserved block group size: %d\n", info.bg_desc_reserve_blocks); 527 printf(" Used %d/%d inodes and %d/%d blocks\n", 528 aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count, 529 aux_info.sb->s_inodes_count, 530 aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo, 531 aux_info.sb->s_blocks_count_lo); 532 } 533 534 return 0; 535 } 536
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