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 #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         off64_t ret;
  98
  99         ret = lseek64(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         off64_t ret;
 114
 115         ret = lseek64(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 = 0;
 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         off64_t ret;
 496         struct ext4_super_block sb;
 497
 498         read_sb(fd, &sb);
 499
 500         ext4_parse_sb_info(&sb);
 501
 502         ret = lseek64(fd, info.len, SEEK_SET);
 503         if (ret < 0)
 504                 critical_error_errno("failed to seek to end of input image");
 505
 506         ret = lseek64(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