ext4_utils.c

   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 #ifdef USE_MINGW
  33 #include <winsock2.h>
  34 #else
  35 #include <arpa/inet.h>
  36 #include <sys/ioctl.h>
  37 #endif
  38
  39 #if defined(__linux__)
  40 #include <linux/fs.h>
  41 #elif defined(__APPLE__) && defined(__MACH__)
  42 #include <sys/disk.h>
  43 #endif
  44
  45 int force = 0;
  46 struct fs_info info;
  47 struct fs_aux_info aux_info;
  48 struct sparse_file *ext4_sparse_file;
  49
  50 jmp_buf setjmp_env;
  51
  52 /* returns 1 if a is a power of b */
  53 static int is_power_of(int a, int b)
  54 {
  55         while (a > b) {
  56                 if (a % b)
  57                         return 0;
  58                 a /= b;
  59         }
  60
  61         return (a == b) ? 1 : 0;
  62 }
  63
  64 int bitmap_get_bit(u8 *bitmap, u32 bit)
  65 {
  66         if (bitmap[bit / 8] & (1 << (bit % 8)))
  67                 return 1;
  68
  69         return 0;
  70 }
  71
  72 void bitmap_clear_bit(u8 *bitmap, u32 bit)
  73 {
  74         bitmap[bit / 8] &= ~(1 << (bit % 8));
  75
  76         return;
  77 }
  78
  79 /* Returns 1 if the bg contains a backup superblock.  On filesystems with
  80    the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
  81    and 7 have backup superblocks.  Otherwise, all block groups have backup
  82    superblocks */
  83 int ext4_bg_has_super_block(int bg)
  84 {
  85         /* Without sparse_super, every block group has a superblock */
  86         if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
  87                 return 1;
  88
  89         if (bg == 0 || bg == 1)
  90                 return 1;
  91
  92         if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7))
  93                 return 1;
  94
  95         return 0;
  96 }
  97
  98 /* Function to read the primary superblock */
  99 void read_sb(int fd, struct ext4_super_block *sb)
 100 {
 101         off64_t ret;
 102
 103         ret = lseek64(fd, 1024, SEEK_SET);
 104         if (ret < 0)
 105                 critical_error_errno("failed to seek to superblock");
 106
 107         ret = read(fd, sb, sizeof(*sb));
 108         if (ret < 0)
 109                 critical_error_errno("failed to read superblock");
 110         if (ret != sizeof(*sb))
 111                 critical_error("failed to read all of superblock");
 112 }
 113
 114 /* Function to write a primary or backup superblock at a given offset */
 115 void write_sb(int fd, unsigned long long offset, struct ext4_super_block *sb)
 116 {
 117         off64_t ret;
 118
 119         ret = lseek64(fd, offset, SEEK_SET);
 120         if (ret < 0)
 121                 critical_error_errno("failed to seek to superblock");
 122
 123         ret = write(fd, sb, sizeof(*sb));
 124         if (ret < 0)
 125                 critical_error_errno("failed to write superblock");
 126         if (ret != sizeof(*sb))
 127                 critical_error("failed to write all of superblock");
 128 }
 129
 130 /* Write the filesystem image to a file */
 131 void write_ext4_image(int fd, int gz, int sparse, int crc)
 132 {
 133         sparse_file_write(ext4_sparse_file, fd, gz, sparse, crc);
 134 }
 135
 136 /* Compute the rest of the parameters of the filesystem from the basic info */
 137 void ext4_create_fs_aux_info()
 138 {
 139         aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
 140         aux_info.len_blocks = info.len / info.block_size;
 141         aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
 142                 info.block_size);
 143         aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
 144                 info.blocks_per_group);
 145         aux_info.blocks_per_ind = info.block_size / sizeof(u32);
 146         aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
 147         aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;
 148
 149         aux_info.bg_desc_blocks =
 150                 DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
 151                         info.block_size);
 152
 153         aux_info.default_i_flags = EXT4_NOATIME_FL;
 154
 155         u32 last_group_size = aux_info.len_blocks % info.blocks_per_group;
 156         u32 last_header_size = 2 + aux_info.inode_table_blocks;
 157         if (ext4_bg_has_super_block(aux_info.groups - 1))
 158                 last_header_size += 1 + aux_info.bg_desc_blocks +
 159                         info.bg_desc_reserve_blocks;
 160         if (last_group_size > 0 && last_group_size < last_header_size) {
 161                 aux_info.groups--;
 162                 aux_info.len_blocks -= last_group_size;
 163         }
 164
 165         aux_info.sb = calloc(info.block_size, 1);
 166         /* Alloc an array to hold the pointers to the backup superblocks */
 167         aux_info.backup_sb = calloc(aux_info.groups, sizeof(char *));
 168
 169         if (!aux_info.sb)
 170                 critical_error_errno("calloc");
 171
 172         aux_info.bg_desc = calloc(info.block_size, aux_info.bg_desc_blocks);
 173         if (!aux_info.bg_desc)
 174                 critical_error_errno("calloc");
 175         aux_info.xattrs = NULL;
 176 }
 177
 178 void ext4_free_fs_aux_info()
 179 {
 180         unsigned int i;
 181
 182         for (i=0; i<aux_info.groups; i++) {
 183                 if (aux_info.backup_sb[i])
 184                         free(aux_info.backup_sb[i]);
 185         }
 186         free(aux_info.sb);
 187         free(aux_info.bg_desc);
 188 }
 189
 190 /* Fill in the superblock memory buffer based on the filesystem parameters */
 191 void ext4_fill_in_sb()
 192 {
 193         unsigned int i;
 194         struct ext4_super_block *sb = aux_info.sb;
 195
 196         sb->s_inodes_count = info.inodes_per_group * aux_info.groups;
 197         sb->s_blocks_count_lo = aux_info.len_blocks;
 198         sb->s_r_blocks_count_lo = 0;
 199         sb->s_free_blocks_count_lo = 0;
 200         sb->s_free_inodes_count = 0;
 201         sb->s_first_data_block = aux_info.first_data_block;
 202         sb->s_log_block_size = log_2(info.block_size / 1024);
 203         sb->s_obso_log_frag_size = log_2(info.block_size / 1024);
 204         sb->s_blocks_per_group = info.blocks_per_group;
 205         sb->s_obso_frags_per_group = info.blocks_per_group;
 206         sb->s_inodes_per_group = info.inodes_per_group;
 207         sb->s_mtime = 0;
 208         sb->s_wtime = 0;
 209         sb->s_mnt_count = 0;
 210         sb->s_max_mnt_count = 0xFFFF;
 211         sb->s_magic = EXT4_SUPER_MAGIC;
 212         sb->s_state = EXT4_VALID_FS;
 213         sb->s_errors = EXT4_ERRORS_RO;
 214         sb->s_minor_rev_level = 0;
 215         sb->s_lastcheck = 0;
 216         sb->s_checkinterval = 0;
 217         sb->s_creator_os = EXT4_OS_LINUX;
 218         sb->s_rev_level = EXT4_DYNAMIC_REV;
 219         sb->s_def_resuid = EXT4_DEF_RESUID;
 220         sb->s_def_resgid = EXT4_DEF_RESGID;
 221
 222         sb->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
 223         sb->s_inode_size = info.inode_size;
 224         sb->s_block_group_nr = 0;
 225         sb->s_feature_compat = info.feat_compat;
 226         sb->s_feature_incompat = info.feat_incompat;
 227         sb->s_feature_ro_compat = info.feat_ro_compat;
 228         generate_uuid("extandroid/make_ext4fs", info.label, sb->s_uuid);
 229         memset(sb->s_volume_name, 0, sizeof(sb->s_volume_name));
 230         strncpy(sb->s_volume_name, info.label, sizeof(sb->s_volume_name));
 231         memset(sb->s_last_mounted, 0, sizeof(sb->s_last_mounted));
 232         sb->s_algorithm_usage_bitmap = 0;
 233
 234         sb->s_reserved_gdt_blocks = info.bg_desc_reserve_blocks;
 235         sb->s_prealloc_blocks = 0;
 236         sb->s_prealloc_dir_blocks = 0;
 237
 238         //memcpy(sb->s_journal_uuid, sb->s_uuid, sizeof(sb->s_journal_uuid));
 239         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 240                 sb->s_journal_inum = EXT4_JOURNAL_INO;
 241         sb->s_journal_dev = 0;
 242         sb->s_last_orphan = 0;
 243         sb->s_hash_seed[0] = 0; /* FIXME */
 244         sb->s_def_hash_version = DX_HASH_TEA;
 245         sb->s_reserved_char_pad = EXT4_JNL_BACKUP_BLOCKS;
 246         sb->s_desc_size = sizeof(struct ext2_group_desc);
 247         sb->s_default_mount_opts = 0; /* FIXME */
 248         sb->s_first_meta_bg = 0;
 249         sb->s_mkfs_time = 0;
 250         //sb->s_jnl_blocks[17]; /* FIXME */
 251
 252         sb->s_blocks_count_hi = aux_info.len_blocks >> 32;
 253         sb->s_r_blocks_count_hi = 0;
 254         sb->s_free_blocks_count_hi = 0;
 255         sb->s_min_extra_isize = sizeof(struct ext4_inode) -
 256                 EXT4_GOOD_OLD_INODE_SIZE;
 257         sb->s_want_extra_isize = sizeof(struct ext4_inode) -
 258                 EXT4_GOOD_OLD_INODE_SIZE;
 259         sb->s_flags = 2;
 260         sb->s_raid_stride = 0;
 261         sb->s_mmp_interval = 0;
 262         sb->s_mmp_block = 0;
 263         sb->s_raid_stripe_width = 0;
 264         sb->s_log_groups_per_flex = 0;
 265         sb->s_kbytes_written = 0;
 266
 267         for (i = 0; i < aux_info.groups; i++) {
 268                 u64 group_start_block = aux_info.first_data_block + i *
 269                         info.blocks_per_group;
 270                 u32 header_size = 0;
 271                 if (ext4_bg_has_super_block(i)) {
 272                         if (i != 0) {
 273                                 aux_info.backup_sb[i] = calloc(info.block_size, 1);
 274                                 memcpy(aux_info.backup_sb[i], sb, info.block_size);
 275                                 /* Update the block group nr of this backup superblock */
 276                                 aux_info.backup_sb[i]->s_block_group_nr = i;
 277                                 sparse_file_add_data(ext4_sparse_file, aux_info.backup_sb[i],
 278                                                 info.block_size, group_start_block);
 279                         }
 280                         sparse_file_add_data(ext4_sparse_file, aux_info.bg_desc,
 281                                 aux_info.bg_desc_blocks * info.block_size,
 282                                 group_start_block + 1);
 283                         header_size = 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks;
 284                 }
 285
 286                 aux_info.bg_desc[i].bg_block_bitmap = group_start_block + header_size;
 287                 aux_info.bg_desc[i].bg_inode_bitmap = group_start_block + header_size + 1;
 288                 aux_info.bg_desc[i].bg_inode_table = group_start_block + header_size + 2;
 289
 290                 aux_info.bg_desc[i].bg_free_blocks_count = sb->s_blocks_per_group;
 291                 aux_info.bg_desc[i].bg_free_inodes_count = sb->s_inodes_per_group;
 292                 aux_info.bg_desc[i].bg_used_dirs_count = 0;
 293         }
 294 }
 295
 296 void ext4_queue_sb(void)
 297 {
 298         /* The write_data* functions expect only block aligned calls.
 299          * This is not an issue, except when we write out the super
 300          * block on a system with a block size > 1K.  So, we need to
 301          * deal with that here.
 302          */
 303         if (info.block_size > 1024) {
 304                 u8 *buf = calloc(info.block_size, 1);
 305                 memcpy(buf + 1024, (u8*)aux_info.sb, 1024);
 306                 sparse_file_add_data(ext4_sparse_file, buf, info.block_size, 0);
 307         } else {
 308                 sparse_file_add_data(ext4_sparse_file, aux_info.sb, 1024, 1);
 309         }
 310 }
 311
 312 void ext4_parse_sb_info(struct ext4_super_block *sb)
 313 {
 314         if (sb->s_magic != EXT4_SUPER_MAGIC)
 315                 error("superblock magic incorrect");
 316
 317         if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS)
 318                 error("filesystem state not valid");
 319
 320         ext4_parse_sb(sb, &info);
 321
 322         ext4_create_fs_aux_info();
 323
 324         memcpy(aux_info.sb, sb, sizeof(*sb));
 325
 326         if (aux_info.first_data_block != sb->s_first_data_block)
 327                 critical_error("first data block does not match");
 328 }
 329
 330 void ext4_create_resize_inode()
 331 {
 332         struct block_allocation *reserve_inode_alloc = create_allocation();
 333         u32 reserve_inode_len = 0;
 334         unsigned int i;
 335
 336         struct ext4_inode *inode = get_inode(EXT4_RESIZE_INO);
 337         if (inode == NULL) {
 338                 error("failed to get resize inode");
 339                 return;
 340         }
 341
 342         for (i = 0; i < aux_info.groups; i++) {
 343                 if (ext4_bg_has_super_block(i)) {
 344                         u64 group_start_block = aux_info.first_data_block + i *
 345                                 info.blocks_per_group;
 346                         u32 reserved_block_start = group_start_block + 1 +
 347                                 aux_info.bg_desc_blocks;
 348                         u32 reserved_block_len = info.bg_desc_reserve_blocks;
 349                         append_region(reserve_inode_alloc, reserved_block_start,
 350                                 reserved_block_len, i);
 351                         reserve_inode_len += reserved_block_len;
 352                 }
 353         }
 354
 355         inode_attach_resize(inode, reserve_inode_alloc);
 356
 357         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 358         inode->i_links_count = 1;
 359
 360         free_alloc(reserve_inode_alloc);
 361 }
 362
 363 /* Allocate the blocks to hold a journal inode and connect them to the
 364    reserved journal inode */
 365 void ext4_create_journal_inode()
 366 {
 367         struct ext4_inode *inode = get_inode(EXT4_JOURNAL_INO);
 368         if (inode == NULL) {
 369                 error("failed to get journal inode");
 370                 return;
 371         }
 372
 373         u8 *journal_data = inode_allocate_data_extents(inode,
 374                         info.journal_blocks * info.block_size,
 375                         info.journal_blocks * info.block_size);
 376         if (!journal_data) {
 377                 error("failed to allocate extents for journal data");
 378                 return;
 379         }
 380
 381         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 382         inode->i_links_count = 1;
 383
 384         journal_superblock_t *jsb = (journal_superblock_t *)journal_data;
 385         jsb->s_header.h_magic = htonl(JBD2_MAGIC_NUMBER);
 386         jsb->s_header.h_blocktype = htonl(JBD2_SUPERBLOCK_V2);
 387         jsb->s_blocksize = htonl(info.block_size);
 388         jsb->s_maxlen = htonl(info.journal_blocks);
 389         jsb->s_nr_users = htonl(1);
 390         jsb->s_first = htonl(1);
 391         jsb->s_sequence = htonl(1);
 392
 393         memcpy(aux_info.sb->s_jnl_blocks, &inode->i_block, sizeof(inode->i_block));
 394 }
 395
 396 /* Update the number of free blocks and inodes in the filesystem and in each
 397    block group */
 398 void ext4_update_free()
 399 {
 400         u32 i;
 401
 402         for (i = 0; i < aux_info.groups; i++) {
 403                 u32 bg_free_blocks = get_free_blocks(i);
 404                 u32 bg_free_inodes = get_free_inodes(i);
 405                 u16 crc;
 406
 407                 aux_info.bg_desc[i].bg_free_blocks_count = bg_free_blocks;
 408                 aux_info.sb->s_free_blocks_count_lo += bg_free_blocks;
 409
 410                 aux_info.bg_desc[i].bg_free_inodes_count = bg_free_inodes;
 411                 aux_info.sb->s_free_inodes_count += bg_free_inodes;
 412
 413                 aux_info.bg_desc[i].bg_used_dirs_count += get_directories(i);
 414
 415                 aux_info.bg_desc[i].bg_flags = get_bg_flags(i);
 416
 417                 crc = ext4_crc16(~0, aux_info.sb->s_uuid, sizeof(aux_info.sb->s_uuid));
 418                 crc = ext4_crc16(crc, &i, sizeof(i));
 419                 crc = ext4_crc16(crc, &aux_info.bg_desc[i], offsetof(struct ext2_group_desc, bg_checksum));
 420                 aux_info.bg_desc[i].bg_checksum = crc;
 421         }
 422 }
 423
 424 u64 get_block_device_size(int fd)
 425 {
 426         u64 size = 0;
 427         int ret;
 428
 429 #if defined(__linux__)
 430         ret = ioctl(fd, BLKGETSIZE64, &size);
 431 #elif defined(__APPLE__) && defined(__MACH__)
 432         ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
 433 #else
 434         close(fd);
 435         return 0;
 436 #endif
 437
 438         if (ret)
 439                 return 0;
 440
 441         return size;
 442 }
 443
 444 int is_block_device_fd(int fd)
 445 {
 446 #ifdef USE_MINGW
 447         return 0;
 448 #else
 449         struct stat st;
 450         int ret = fstat(fd, &st);
 451         if (ret < 0)
 452                 return 0;
 453
 454         return S_ISBLK(st.st_mode);
 455 #endif
 456 }
 457
 458 u64 get_file_size(int fd)
 459 {
 460         struct stat buf;
 461         int ret;
 462         u64 reserve_len = 0;
 463         s64 computed_size;
 464
 465         ret = fstat(fd, &buf);
 466         if (ret)
 467                 return 0;
 468
 469         if (info.len < 0)
 470                 reserve_len = -info.len;
 471
 472         if (S_ISREG(buf.st_mode))
 473                 computed_size = buf.st_size - reserve_len;
 474         else if (S_ISBLK(buf.st_mode))
 475                 computed_size = get_block_device_size(fd) - reserve_len;
 476         else
 477                 computed_size = 0;
 478
 479         if (computed_size < 0) {
 480                 warn("Computed filesystem size less than 0");
 481                 computed_size = 0;
 482         }
 483
 484         return computed_size;
 485 }
 486
 487 u64 parse_num(const char *arg)
 488 {
 489         char *endptr;
 490         u64 num = strtoull(arg, &endptr, 10);
 491         if (*endptr == 'k' || *endptr == 'K')
 492                 num *= 1024LL;
 493         else if (*endptr == 'm' || *endptr == 'M')
 494                 num *= 1024LL * 1024LL;
 495         else if (*endptr == 'g' || *endptr == 'G')
 496                 num *= 1024LL * 1024LL * 1024LL;
 497
 498         return num;
 499 }
 500
 501 int read_ext(int fd, int verbose)
 502 {
 503         off64_t ret;
 504         struct ext4_super_block sb;
 505
 506         read_sb(fd, &sb);
 507
 508         ext4_parse_sb_info(&sb);
 509
 510         ret = lseek64(fd, info.len, SEEK_SET);
 511         if (ret < 0)
 512                 critical_error_errno("failed to seek to end of input image");
 513
 514         ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
 515         if (ret < 0)
 516                 critical_error_errno("failed to seek to block group descriptors");
 517
 518         ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
 519         if (ret < 0)
 520                 critical_error_errno("failed to read block group descriptors");
 521         if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
 522                 critical_error("failed to read all of block group descriptors");
 523
 524         if (verbose) {
 525                 printf("Found filesystem with parameters:\n");
 526                 printf("    Size: %"PRIu64"\n", info.len);
 527                 printf("    Block size: %d\n", info.block_size);
 528                 printf("    Blocks per group: %d\n", info.blocks_per_group);
 529                 printf("    Inodes per group: %d\n", info.inodes_per_group);
 530                 printf("    Inode size: %d\n", info.inode_size);
 531                 printf("    Label: %s\n", info.label);
 532                 printf("    Blocks: %"PRIu64"\n", aux_info.len_blocks);
 533                 printf("    Block groups: %d\n", aux_info.groups);
 534                 printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 535                 printf("    Used %d/%d inodes and %d/%d blocks\n",
 536                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 537                         aux_info.sb->s_inodes_count,
 538                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 539                         aux_info.sb->s_blocks_count_lo);
 540         }
 541
 542         return 0;
 543 }
 544