ext4_utils/make_ext4fs.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 "make_ext4fs.h"
  18 #include "ext4_utils.h"
  19 #include "allocate.h"
  20 #include "contents.h"
  21 #include "uuid.h"
  22 #include "wipe.h"
  23
  24 #include <sparse/sparse.h>
  25
  26 #include <assert.h>
  27 #include <dirent.h>
  28 #include <fcntl.h>
  29 #include <libgen.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34 #include <sys/stat.h>
  35 #include <sys/types.h>
  36
  37 #ifdef USE_MINGW
  38
  39 #include <winsock2.h>
  40
  41 /* These match the Linux definitions of these flags.
  42    L_xx is defined to avoid conflicting with the win32 versions.
  43 */
  44 #define L_S_IRUSR 00400
  45 #define L_S_IWUSR 00200
  46 #define L_S_IXUSR 00100
  47 #define S_IRWXU (L_S_IRUSR | L_S_IWUSR | L_S_IXUSR)
  48 #define S_IRGRP 00040
  49 #define S_IWGRP 00020
  50 #define S_IXGRP 00010
  51 #define S_IRWXG (S_IRGRP | S_IWGRP | S_IXGRP)
  52 #define S_IROTH 00004
  53 #define S_IWOTH 00002
  54 #define S_IXOTH 00001
  55 #define S_IRWXO (S_IROTH | S_IWOTH | S_IXOTH)
  56 #define S_ISUID 0004000
  57 #define S_ISGID 0002000
  58 #define S_ISVTX 0001000
  59
  60 #else
  61
  62 #define O_BINARY 0
  63
  64 #endif
  65
  66 /* TODO: Not implemented:
  67    Allocating blocks in the same block group as the file inode
  68    Hash or binary tree directories
  69    Special files: sockets, devices, fifos
  70  */
  71
  72 static int filter_dot(const struct dirent *d)
  73 {
  74         return (strcmp(d->d_name, "..") && strcmp(d->d_name, "."));
  75 }
  76
  77 static u32 build_default_directory_structure()
  78 {
  79         u32 inode;
  80         u32 root_inode;
  81         struct dentry dentries = {
  82                         .filename = "lost+found",
  83                         .file_type = EXT4_FT_DIR,
  84                         .mode = S_IRWXU,
  85                         .uid = 0,
  86                         .gid = 0,
  87                         .mtime = 0,
  88         };
  89         root_inode = make_directory(0, 1, &dentries, 1);
  90         inode = make_directory(root_inode, 0, NULL, 0);
  91         *dentries.inode = inode;
  92         inode_set_permissions(inode, dentries.mode,
  93                 dentries.uid, dentries.gid, dentries.mtime);
  94
  95         return root_inode;
  96 }
  97
  98 #ifndef USE_MINGW
  99 /* Read a local directory and create the same tree in the generated filesystem.
 100    Calls itself recursively with each directory in the given directory.
 101    full_path is an absolute or relative path, with a trailing slash, to the
 102    directory on disk that should be copied, or NULL if this is a directory
 103    that does not exist on disk (e.g. lost+found).
 104    dir_path is an absolute path, with trailing slash, to the same directory
 105    if the image were mounted at the specified mount point */
 106 static u32 build_directory_structure(const char *full_path, const char *dir_path,
 107                 u32 dir_inode, fs_config_func_t fs_config_func,
 108                 struct selabel_handle *sehnd)
 109 {
 110         int entries = 0;
 111         struct dentry *dentries;
 112         struct dirent **namelist = NULL;
 113         struct stat stat;
 114         int ret;
 115         int i;
 116         u32 inode;
 117         u32 entry_inode;
 118         u32 dirs = 0;
 119         bool needs_lost_and_found = false;
 120
 121         if (full_path) {
 122                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
 123                 if (entries < 0) {
 124                         error_errno("scandir");
 125                         return EXT4_ALLOCATE_FAILED;
 126                 }
 127         }
 128
 129         if (dir_inode == 0) {
 130                 /* root directory, check if lost+found already exists */
 131                 for (i = 0; i < entries; i++)
 132                         if (strcmp(namelist[i]->d_name, "lost+found") == 0)
 133                                 break;
 134                 if (i == entries)
 135                         needs_lost_and_found = true;
 136         }
 137
 138         dentries = calloc(entries, sizeof(struct dentry));
 139         if (dentries == NULL)
 140                 critical_error_errno("malloc");
 141
 142         for (i = 0; i < entries; i++) {
 143                 dentries[i].filename = strdup(namelist[i]->d_name);
 144                 if (dentries[i].filename == NULL)
 145                         critical_error_errno("strdup");
 146
 147                 asprintf(&dentries[i].path, "%s%s", dir_path, namelist[i]->d_name);
 148                 asprintf(&dentries[i].full_path, "%s%s", full_path, namelist[i]->d_name);
 149
 150                 free(namelist[i]);
 151
 152                 ret = lstat(dentries[i].full_path, &stat);
 153                 if (ret < 0) {
 154                         error_errno("lstat");
 155                         i--;
 156                         entries--;
 157                         continue;
 158                 }
 159
 160                 dentries[i].size = stat.st_size;
 161                 dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO);
 162                 dentries[i].mtime = stat.st_mtime;
 163                 if (fs_config_func != NULL) {
 164 #ifdef ANDROID
 165                         unsigned int mode = 0;
 166                         unsigned int uid = 0;
 167                         unsigned int gid = 0;
 168                         int dir = S_ISDIR(stat.st_mode);
 169                         fs_config_func(dentries[i].path, dir, &uid, &gid, &mode);
 170                         dentries[i].mode = mode;
 171                         dentries[i].uid = uid;
 172                         dentries[i].gid = gid;
 173 #else
 174                         error("can't set android permissions - built without android support");
 175 #endif
 176                 }
 177 #ifndef USE_MINGW
 178                 if (sehnd) {
 179                         if (selabel_lookup(sehnd, &dentries[i].secon, dentries[i].path, stat.st_mode) < 0) {
 180                                 error("cannot lookup security context for %s", dentries[i].path);
 181                         }
 182 #if 0
 183                         // TODO make this a debug flag
 184                         if (dentries[i].secon)
 185                                 printf("Labeling %s as %s\n", dentries[i].path, dentries[i].secon);
 186 #endif
 187                 }
 188 #endif
 189
 190                 if (S_ISREG(stat.st_mode)) {
 191                         dentries[i].file_type = EXT4_FT_REG_FILE;
 192                 } else if (S_ISDIR(stat.st_mode)) {
 193                         dentries[i].file_type = EXT4_FT_DIR;
 194                         dirs++;
 195                 } else if (S_ISCHR(stat.st_mode)) {
 196                         dentries[i].file_type = EXT4_FT_CHRDEV;
 197                 } else if (S_ISBLK(stat.st_mode)) {
 198                         dentries[i].file_type = EXT4_FT_BLKDEV;
 199                 } else if (S_ISFIFO(stat.st_mode)) {
 200                         dentries[i].file_type = EXT4_FT_FIFO;
 201                 } else if (S_ISSOCK(stat.st_mode)) {
 202                         dentries[i].file_type = EXT4_FT_SOCK;
 203                 } else if (S_ISLNK(stat.st_mode)) {
 204                         dentries[i].file_type = EXT4_FT_SYMLINK;
 205                         dentries[i].link = calloc(info.block_size, 1);
 206                         readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
 207                 } else {
 208                         error("unknown file type on %s", dentries[i].path);
 209                         i--;
 210                         entries--;
 211                 }
 212         }
 213         free(namelist);
 214
 215         if (needs_lost_and_found) {
 216                 /* insert a lost+found directory at the beginning of the dentries */
 217                 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry));
 218                 memset(tmp, 0, sizeof(struct dentry));
 219                 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry));
 220                 dentries = tmp;
 221
 222                 dentries[0].filename = strdup("lost+found");
 223                 asprintf(&dentries[0].path, "%slost+found", dir_path);
 224                 dentries[0].full_path = NULL;
 225                 dentries[0].size = 0;
 226                 dentries[0].mode = S_IRWXU;
 227                 dentries[0].file_type = EXT4_FT_DIR;
 228                 dentries[0].uid = 0;
 229                 dentries[0].gid = 0;
 230                 if (sehnd) {
 231                         if (selabel_lookup(sehnd, &dentries[0].secon, dentries[0].path, dentries[0].mode) < 0)
 232                                 error("cannot lookup security context for %s", dentries[0].path);
 233                 }
 234                 entries++;
 235                 dirs++;
 236         }
 237
 238         inode = make_directory(dir_inode, entries, dentries, dirs);
 239
 240         for (i = 0; i < entries; i++) {
 241                 if (dentries[i].file_type == EXT4_FT_REG_FILE) {
 242                         entry_inode = make_file(dentries[i].full_path, dentries[i].size);
 243                 } else if (dentries[i].file_type == EXT4_FT_DIR) {
 244                         char *subdir_full_path = NULL;
 245                         char *subdir_dir_path;
 246                         if (dentries[i].full_path) {
 247                                 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path);
 248                                 if (ret < 0)
 249                                         critical_error_errno("asprintf");
 250                         }
 251                         ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path);
 252                         if (ret < 0)
 253                                 critical_error_errno("asprintf");
 254                         entry_inode = build_directory_structure(subdir_full_path,
 255                                         subdir_dir_path, inode, fs_config_func, sehnd);
 256                         free(subdir_full_path);
 257                         free(subdir_dir_path);
 258                 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
 259                         entry_inode = make_link(dentries[i].full_path, dentries[i].link);
 260                 } else {
 261                         error("unknown file type on %s", dentries[i].path);
 262                         entry_inode = 0;
 263                 }
 264                 *dentries[i].inode = entry_inode;
 265
 266                 ret = inode_set_permissions(entry_inode, dentries[i].mode,
 267                         dentries[i].uid, dentries[i].gid,
 268                         dentries[i].mtime);
 269                 if (ret)
 270                         error("failed to set permissions on %s\n", dentries[i].path);
 271                 ret = inode_set_selinux(entry_inode, dentries[i].secon);
 272                 if (ret)
 273                         error("failed to set SELinux context on %s\n", dentries[i].path);
 274
 275                 free(dentries[i].path);
 276                 free(dentries[i].full_path);
 277                 free(dentries[i].link);
 278                 free((void *)dentries[i].filename);
 279                 free(dentries[i].secon);
 280         }
 281
 282         free(dentries);
 283         return inode;
 284 }
 285 #endif
 286
 287 static u32 compute_block_size()
 288 {
 289         return 4096;
 290 }
 291
 292 static u32 compute_journal_blocks()
 293 {
 294         u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
 295         if (journal_blocks < 1024)
 296                 journal_blocks = 1024;
 297         if (journal_blocks > 32768)
 298                 journal_blocks = 32768;
 299         return journal_blocks;
 300 }
 301
 302 static u32 compute_blocks_per_group()
 303 {
 304         return info.block_size * 8;
 305 }
 306
 307 static u32 compute_inodes()
 308 {
 309         return DIV_ROUND_UP(info.len, info.block_size) / 4;
 310 }
 311
 312 static u32 compute_inodes_per_group()
 313 {
 314         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 315         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 316         u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
 317         inodes = ALIGN(inodes, (info.block_size / info.inode_size));
 318
 319         /* After properly rounding up the number of inodes/group,
 320          * make sure to update the total inodes field in the info struct.
 321          */
 322         info.inodes = inodes * block_groups;
 323
 324         return inodes;
 325 }
 326
 327 static u32 compute_bg_desc_reserve_blocks()
 328 {
 329         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 330         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 331         u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
 332                         info.block_size);
 333
 334         u32 bg_desc_reserve_blocks =
 335                         DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
 336                                         info.block_size) - bg_desc_blocks;
 337
 338         if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
 339                 bg_desc_reserve_blocks = info.block_size / sizeof(u32);
 340
 341         return bg_desc_reserve_blocks;
 342 }
 343
 344 void reset_ext4fs_info() {
 345     // Reset all the global data structures used by make_ext4fs so it
 346     // can be called again.
 347     memset(&info, 0, sizeof(info));
 348     memset(&aux_info, 0, sizeof(aux_info));
 349
 350     if (info.sparse_file) {
 351         sparse_file_destroy(info.sparse_file);
 352         info.sparse_file = NULL;
 353     }
 354 }
 355
 356 int make_ext4fs(const char *filename, s64 len,
 357                 const char *mountpoint, struct selabel_handle *sehnd)
 358 {
 359         int fd;
 360         int status;
 361
 362         reset_ext4fs_info();
 363         info.len = len;
 364
 365         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
 366         if (fd < 0) {
 367                 error_errno("open");
 368                 return EXIT_FAILURE;
 369         }
 370
 371         status = make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 0, 0, 1, 0, sehnd);
 372         close(fd);
 373
 374         return status;
 375 }
 376
 377 /* return a newly-malloc'd string that is a copy of str.  The new string
 378    is guaranteed to have a trailing slash.  If absolute is true, the new string
 379    is also guaranteed to have a leading slash.
 380 */
 381 static char *canonicalize_slashes(const char *str, bool absolute)
 382 {
 383         char *ret;
 384         int len = strlen(str);
 385         int newlen = len;
 386         char *ptr;
 387
 388         if (len == 0 && absolute) {
 389                 return strdup("/");
 390         }
 391
 392         if (str[0] != '/' && absolute) {
 393                 newlen++;
 394         }
 395         if (str[len - 1] != '/') {
 396                 newlen++;
 397         }
 398         ret = malloc(newlen + 1);
 399         if (!ret) {
 400                 critical_error("malloc");
 401         }
 402
 403         ptr = ret;
 404         if (str[0] != '/' && absolute) {
 405                 *ptr++ = '/';
 406         }
 407
 408         strcpy(ptr, str);
 409         ptr += len;
 410
 411         if (str[len - 1] != '/') {
 412                 *ptr++ = '/';
 413         }
 414
 415         if (ptr != ret + newlen) {
 416                 critical_error("assertion failed\n");
 417         }
 418
 419         *ptr = '\0';
 420
 421         return ret;
 422 }
 423
 424 static char *canonicalize_abs_slashes(const char *str)
 425 {
 426         return canonicalize_slashes(str, true);
 427 }
 428
 429 static char *canonicalize_rel_slashes(const char *str)
 430 {
 431         return canonicalize_slashes(str, false);
 432 }
 433
 434 int make_ext4fs_internal(int fd, const char *_directory,
 435                          const char *_mountpoint, fs_config_func_t fs_config_func, int gzip,
 436                          int sparse, int crc, int wipe, int init_itabs,
 437                          struct selabel_handle *sehnd)
 438 {
 439         u32 root_inode_num;
 440         u16 root_mode;
 441         char *mountpoint;
 442         char *directory = NULL;
 443         int ret;
 444
 445         if (setjmp(setjmp_env))
 446                 return EXIT_FAILURE; /* Handle a call to longjmp() */
 447
 448         if (_mountpoint == NULL) {
 449                 mountpoint = strdup("");
 450         } else {
 451                 mountpoint = canonicalize_abs_slashes(_mountpoint);
 452         }
 453
 454         if (_directory) {
 455                 directory = canonicalize_rel_slashes(_directory);
 456         }
 457
 458         if (info.len <= 0)
 459                 info.len = get_file_size(fd);
 460
 461         if (info.len <= 0) {
 462                 fprintf(stderr, "Need size of filesystem\n");
 463                 return EXIT_FAILURE;
 464         }
 465
 466         if (info.block_size <= 0)
 467                 info.block_size = compute_block_size();
 468
 469         /* Round down the filesystem length to be a multiple of the block size */
 470         info.len &= ~((u64)info.block_size - 1);
 471
 472         if (info.journal_blocks == 0)
 473                 info.journal_blocks = compute_journal_blocks();
 474
 475         if (info.no_journal == 0)
 476                 info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL;
 477         else
 478                 info.journal_blocks = 0;
 479
 480         if (info.blocks_per_group <= 0)
 481                 info.blocks_per_group = compute_blocks_per_group();
 482
 483         if (info.inodes <= 0)
 484                 info.inodes = compute_inodes();
 485
 486         if (info.inode_size <= 0)
 487                 info.inode_size = 256;
 488
 489         if (info.label == NULL)
 490                 info.label = "";
 491
 492         info.inodes_per_group = compute_inodes_per_group();
 493
 494         info.feat_compat |=
 495                         EXT4_FEATURE_COMPAT_RESIZE_INODE;
 496
 497         info.feat_ro_compat |=
 498                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER |
 499                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE;
 500
 501         info.feat_incompat |=
 502                         EXT4_FEATURE_INCOMPAT_EXTENTS |
 503                         EXT4_FEATURE_INCOMPAT_FILETYPE;
 504
 505
 506         info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks();
 507
 508         printf("Creating filesystem with parameters:\n");
 509         printf("    Size: %llu\n", info.len);
 510         printf("    Block size: %d\n", info.block_size);
 511         printf("    Blocks per group: %d\n", info.blocks_per_group);
 512         printf("    Inodes per group: %d\n", info.inodes_per_group);
 513         printf("    Inode size: %d\n", info.inode_size);
 514         printf("    Journal blocks: %d\n", info.journal_blocks);
 515         printf("    Label: %s\n", info.label);
 516
 517         ext4_create_fs_aux_info();
 518
 519         printf("    Blocks: %llu\n", aux_info.len_blocks);
 520         printf("    Block groups: %d\n", aux_info.groups);
 521         printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 522
 523         info.sparse_file = sparse_file_new(info.block_size, info.len);
 524
 525         block_allocator_init();
 526
 527         ext4_fill_in_sb();
 528
 529         if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
 530                 error("failed to reserve first 10 inodes");
 531
 532         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 533                 ext4_create_journal_inode();
 534
 535         if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
 536                 ext4_create_resize_inode();
 537
 538 #ifdef USE_MINGW
 539         // Windows needs only 'create an empty fs image' functionality
 540         assert(!directory);
 541         root_inode_num = build_default_directory_structure();
 542 #else
 543         if (directory)
 544                 root_inode_num = build_directory_structure(directory, mountpoint, 0,
 545                         fs_config_func, sehnd);
 546         else
 547                 root_inode_num = build_default_directory_structure();
 548 #endif
 549
 550         root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 551         inode_set_permissions(root_inode_num, root_mode, 0, 0, 0);
 552
 553 #ifndef USE_MINGW
 554         if (sehnd) {
 555                 char *secontext = NULL;
 556
 557                 if (selabel_lookup(sehnd, &secontext, mountpoint, S_IFDIR) < 0) {
 558                         error("cannot lookup security context for %s", mountpoint);
 559                 }
 560                 if (secontext) {
 561                         printf("Labeling %s as %s\n", mountpoint, secontext);
 562                         inode_set_selinux(root_inode_num, secontext);
 563                 }
 564                 freecon(secontext);
 565         }
 566 #endif
 567
 568         ext4_update_free();
 569
 570         if (init_itabs)
 571                 init_unused_inode_tables();
 572
 573         ext4_queue_sb();
 574
 575         printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
 576                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 577                         aux_info.sb->s_inodes_count,
 578                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 579                         aux_info.sb->s_blocks_count_lo);
 580
 581         if (wipe)
 582                 wipe_block_device(fd, info.len);
 583
 584         write_ext4_image(fd, gzip, sparse, crc);
 585
 586         sparse_file_destroy(info.sparse_file);
 587         info.sparse_file = NULL;
 588
 589         free(mountpoint);
 590         free(directory);
 591
 592         return 0;
 593 }