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 #include <selinux/selinux.h>
  63 #include <selinux/label.h>
  64 #include <selinux/android.h>
  65
  66 #define O_BINARY 0
  67
  68 #endif
  69
  70 /* TODO: Not implemented:
  71    Allocating blocks in the same block group as the file inode
  72    Hash or binary tree directories
  73    Special files: sockets, devices, fifos
  74  */
  75
  76 static int filter_dot(const struct dirent *d)
  77 {
  78         return (strcmp(d->d_name, "..") && strcmp(d->d_name, "."));
  79 }
  80
  81 static u32 build_default_directory_structure()
  82 {
  83         u32 inode;
  84         u32 root_inode;
  85         struct dentry dentries = {
  86                         .filename = "lost+found",
  87                         .file_type = EXT4_FT_DIR,
  88                         .mode = S_IRWXU,
  89                         .uid = 0,
  90                         .gid = 0,
  91                         .mtime = 0,
  92         };
  93         root_inode = make_directory(0, 1, &dentries, 1);
  94         inode = make_directory(root_inode, 0, NULL, 0);
  95         *dentries.inode = inode;
  96         inode_set_permissions(inode, dentries.mode,
  97                 dentries.uid, dentries.gid, dentries.mtime);
  98
  99         return root_inode;
 100 }
 101
 102 #ifndef USE_MINGW
 103 /* Read a local directory and create the same tree in the generated filesystem.
 104    Calls itself recursively with each directory in the given directory.
 105    full_path is an absolute or relative path, with a trailing slash, to the
 106    directory on disk that should be copied, or NULL if this is a directory
 107    that does not exist on disk (e.g. lost+found).
 108    dir_path is an absolute path, with trailing slash, to the same directory
 109    if the image were mounted at the specified mount point */
 110 static u32 build_directory_structure(const char *full_path, const char *dir_path,
 111                 u32 dir_inode, fs_config_func_t fs_config_func,
 112                 struct selabel_handle *sehnd, int verbose)
 113 {
 114         int entries = 0;
 115         struct dentry *dentries;
 116         struct dirent **namelist = NULL;
 117         struct stat stat;
 118         int ret;
 119         int i;
 120         u32 inode;
 121         u32 entry_inode;
 122         u32 dirs = 0;
 123         bool needs_lost_and_found = false;
 124
 125         if (full_path) {
 126                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
 127                 if (entries < 0) {
 128                         error_errno("scandir");
 129                         return EXT4_ALLOCATE_FAILED;
 130                 }
 131         }
 132
 133         if (dir_inode == 0) {
 134                 /* root directory, check if lost+found already exists */
 135                 for (i = 0; i < entries; i++)
 136                         if (strcmp(namelist[i]->d_name, "lost+found") == 0)
 137                                 break;
 138                 if (i == entries)
 139                         needs_lost_and_found = true;
 140         }
 141
 142         dentries = calloc(entries, sizeof(struct dentry));
 143         if (dentries == NULL)
 144                 critical_error_errno("malloc");
 145
 146         for (i = 0; i < entries; i++) {
 147                 dentries[i].filename = strdup(namelist[i]->d_name);
 148                 if (dentries[i].filename == NULL)
 149                         critical_error_errno("strdup");
 150
 151                 asprintf(&dentries[i].path, "%s%s", dir_path, namelist[i]->d_name);
 152                 asprintf(&dentries[i].full_path, "%s%s", full_path, namelist[i]->d_name);
 153
 154                 free(namelist[i]);
 155
 156                 ret = lstat(dentries[i].full_path, &stat);
 157                 if (ret < 0) {
 158                         error_errno("lstat");
 159                         i--;
 160                         entries--;
 161                         continue;
 162                 }
 163
 164                 dentries[i].size = stat.st_size;
 165                 dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO);
 166                 dentries[i].mtime = stat.st_mtime;
 167                 if (fs_config_func != NULL) {
 168 #ifdef ANDROID
 169                         unsigned int mode = 0;
 170                         unsigned int uid = 0;
 171                         unsigned int gid = 0;
 172                         int dir = S_ISDIR(stat.st_mode);
 173                         fs_config_func(dentries[i].path, dir, &uid, &gid, &mode);
 174                         dentries[i].mode = mode;
 175                         dentries[i].uid = uid;
 176                         dentries[i].gid = gid;
 177 #else
 178                         error("can't set android permissions - built without android support");
 179 #endif
 180                 }
 181 #ifndef USE_MINGW
 182                 if (sehnd) {
 183                         if (selabel_lookup(sehnd, &dentries[i].secon, dentries[i].path, stat.st_mode) < 0) {
 184                                 error("cannot lookup security context for %s", dentries[i].path);
 185                         }
 186
 187                         if (dentries[i].secon && verbose)
 188                                 printf("Labeling %s as %s\n", dentries[i].path, dentries[i].secon);
 189                 }
 190 #endif
 191
 192                 if (S_ISREG(stat.st_mode)) {
 193                         dentries[i].file_type = EXT4_FT_REG_FILE;
 194                 } else if (S_ISDIR(stat.st_mode)) {
 195                         dentries[i].file_type = EXT4_FT_DIR;
 196                         dirs++;
 197                 } else if (S_ISCHR(stat.st_mode)) {
 198                         dentries[i].file_type = EXT4_FT_CHRDEV;
 199                 } else if (S_ISBLK(stat.st_mode)) {
 200                         dentries[i].file_type = EXT4_FT_BLKDEV;
 201                 } else if (S_ISFIFO(stat.st_mode)) {
 202                         dentries[i].file_type = EXT4_FT_FIFO;
 203                 } else if (S_ISSOCK(stat.st_mode)) {
 204                         dentries[i].file_type = EXT4_FT_SOCK;
 205                 } else if (S_ISLNK(stat.st_mode)) {
 206                         dentries[i].file_type = EXT4_FT_SYMLINK;
 207                         dentries[i].link = calloc(info.block_size, 1);
 208                         readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
 209                 } else {
 210                         error("unknown file type on %s", dentries[i].path);
 211                         i--;
 212                         entries--;
 213                 }
 214         }
 215         free(namelist);
 216
 217         if (needs_lost_and_found) {
 218                 /* insert a lost+found directory at the beginning of the dentries */
 219                 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry));
 220                 memset(tmp, 0, sizeof(struct dentry));
 221                 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry));
 222                 dentries = tmp;
 223
 224                 dentries[0].filename = strdup("lost+found");
 225                 asprintf(&dentries[0].path, "%slost+found", dir_path);
 226                 dentries[0].full_path = NULL;
 227                 dentries[0].size = 0;
 228                 dentries[0].mode = S_IRWXU;
 229                 dentries[0].file_type = EXT4_FT_DIR;
 230                 dentries[0].uid = 0;
 231                 dentries[0].gid = 0;
 232                 if (sehnd) {
 233                         if (selabel_lookup(sehnd, &dentries[0].secon, dentries[0].path, dentries[0].mode) < 0)
 234                                 error("cannot lookup security context for %s", dentries[0].path);
 235                 }
 236                 entries++;
 237                 dirs++;
 238         }
 239
 240         inode = make_directory(dir_inode, entries, dentries, dirs);
 241
 242         for (i = 0; i < entries; i++) {
 243                 if (dentries[i].file_type == EXT4_FT_REG_FILE) {
 244                         entry_inode = make_file(dentries[i].full_path, dentries[i].size);
 245                 } else if (dentries[i].file_type == EXT4_FT_DIR) {
 246                         char *subdir_full_path = NULL;
 247                         char *subdir_dir_path;
 248                         if (dentries[i].full_path) {
 249                                 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path);
 250                                 if (ret < 0)
 251                                         critical_error_errno("asprintf");
 252                         }
 253                         ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path);
 254                         if (ret < 0)
 255                                 critical_error_errno("asprintf");
 256                         entry_inode = build_directory_structure(subdir_full_path,
 257                                         subdir_dir_path, inode, fs_config_func, sehnd, verbose);
 258                         free(subdir_full_path);
 259                         free(subdir_dir_path);
 260                 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
 261                         entry_inode = make_link(dentries[i].full_path, dentries[i].link);
 262                 } else {
 263                         error("unknown file type on %s", dentries[i].path);
 264                         entry_inode = 0;
 265                 }
 266                 *dentries[i].inode = entry_inode;
 267
 268                 ret = inode_set_permissions(entry_inode, dentries[i].mode,
 269                         dentries[i].uid, dentries[i].gid,
 270                         dentries[i].mtime);
 271                 if (ret)
 272                         error("failed to set permissions on %s\n", dentries[i].path);
 273                 ret = inode_set_selinux(entry_inode, dentries[i].secon);
 274                 if (ret)
 275                         error("failed to set SELinux context on %s\n", dentries[i].path);
 276
 277                 free(dentries[i].path);
 278                 free(dentries[i].full_path);
 279                 free(dentries[i].link);
 280                 free((void *)dentries[i].filename);
 281                 free(dentries[i].secon);
 282         }
 283
 284         free(dentries);
 285         return inode;
 286 }
 287 #endif
 288
 289 static u32 compute_block_size()
 290 {
 291         return 4096;
 292 }
 293
 294 static u32 compute_journal_blocks()
 295 {
 296         u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
 297         if (journal_blocks < 1024)
 298                 journal_blocks = 1024;
 299         if (journal_blocks > 32768)
 300                 journal_blocks = 32768;
 301         return journal_blocks;
 302 }
 303
 304 static u32 compute_blocks_per_group()
 305 {
 306         return info.block_size * 8;
 307 }
 308
 309 static u32 compute_inodes()
 310 {
 311         return DIV_ROUND_UP(info.len, info.block_size) / 4;
 312 }
 313
 314 static u32 compute_inodes_per_group()
 315 {
 316         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 317         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 318         u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
 319         inodes = ALIGN(inodes, (info.block_size / info.inode_size));
 320
 321         /* After properly rounding up the number of inodes/group,
 322          * make sure to update the total inodes field in the info struct.
 323          */
 324         info.inodes = inodes * block_groups;
 325
 326         return inodes;
 327 }
 328
 329 static u32 compute_bg_desc_reserve_blocks()
 330 {
 331         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 332         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 333         u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
 334                         info.block_size);
 335
 336         u32 bg_desc_reserve_blocks =
 337                         DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
 338                                         info.block_size) - bg_desc_blocks;
 339
 340         if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
 341                 bg_desc_reserve_blocks = info.block_size / sizeof(u32);
 342
 343         return bg_desc_reserve_blocks;
 344 }
 345
 346 void reset_ext4fs_info() {
 347     // Reset all the global data structures used by make_ext4fs so it
 348     // can be called again.
 349     memset(&info, 0, sizeof(info));
 350     memset(&aux_info, 0, sizeof(aux_info));
 351
 352     if (info.sparse_file) {
 353         sparse_file_destroy(info.sparse_file);
 354         info.sparse_file = NULL;
 355     }
 356 }
 357
 358 int make_ext4fs_sparse_fd(int fd, long long len,
 359                 const char *mountpoint, struct selabel_handle *sehnd)
 360 {
 361         reset_ext4fs_info();
 362         info.len = len;
 363
 364         return make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 1, 0, 0, sehnd, 0);
 365 }
 366
 367 int make_ext4fs(const char *filename, long long len,
 368                 const char *mountpoint, struct selabel_handle *sehnd)
 369 {
 370         int fd;
 371         int status;
 372
 373         reset_ext4fs_info();
 374         info.len = len;
 375
 376         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
 377         if (fd < 0) {
 378                 error_errno("open");
 379                 return EXIT_FAILURE;
 380         }
 381
 382         status = make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 0, 0, 1, sehnd, 0);
 383         close(fd);
 384
 385         return status;
 386 }
 387
 388 /* return a newly-malloc'd string that is a copy of str.  The new string
 389    is guaranteed to have a trailing slash.  If absolute is true, the new string
 390    is also guaranteed to have a leading slash.
 391 */
 392 static char *canonicalize_slashes(const char *str, bool absolute)
 393 {
 394         char *ret;
 395         int len = strlen(str);
 396         int newlen = len;
 397         char *ptr;
 398
 399         if (len == 0 && absolute) {
 400                 return strdup("/");
 401         }
 402
 403         if (str[0] != '/' && absolute) {
 404                 newlen++;
 405         }
 406         if (str[len - 1] != '/') {
 407                 newlen++;
 408         }
 409         ret = malloc(newlen + 1);
 410         if (!ret) {
 411                 critical_error("malloc");
 412         }
 413
 414         ptr = ret;
 415         if (str[0] != '/' && absolute) {
 416                 *ptr++ = '/';
 417         }
 418
 419         strcpy(ptr, str);
 420         ptr += len;
 421
 422         if (str[len - 1] != '/') {
 423                 *ptr++ = '/';
 424         }
 425
 426         if (ptr != ret + newlen) {
 427                 critical_error("assertion failed\n");
 428         }
 429
 430         *ptr = '\0';
 431
 432         return ret;
 433 }
 434
 435 static char *canonicalize_abs_slashes(const char *str)
 436 {
 437         return canonicalize_slashes(str, true);
 438 }
 439
 440 static char *canonicalize_rel_slashes(const char *str)
 441 {
 442         return canonicalize_slashes(str, false);
 443 }
 444
 445 int make_ext4fs_internal(int fd, const char *_directory,
 446                          const char *_mountpoint, fs_config_func_t fs_config_func, int gzip,
 447                          int sparse, int crc, int wipe,
 448                          struct selabel_handle *sehnd, int verbose)
 449 {
 450         u32 root_inode_num;
 451         u16 root_mode;
 452         char *mountpoint;
 453         char *directory = NULL;
 454         int ret;
 455
 456         if (setjmp(setjmp_env))
 457                 return EXIT_FAILURE; /* Handle a call to longjmp() */
 458
 459         if (_mountpoint == NULL) {
 460                 mountpoint = strdup("");
 461         } else {
 462                 mountpoint = canonicalize_abs_slashes(_mountpoint);
 463         }
 464
 465         if (_directory) {
 466                 directory = canonicalize_rel_slashes(_directory);
 467         }
 468
 469         if (info.len <= 0)
 470                 info.len = get_file_size(fd);
 471
 472         if (info.len <= 0) {
 473                 fprintf(stderr, "Need size of filesystem\n");
 474                 return EXIT_FAILURE;
 475         }
 476
 477         if (info.block_size <= 0)
 478                 info.block_size = compute_block_size();
 479
 480         /* Round down the filesystem length to be a multiple of the block size */
 481         info.len &= ~((u64)info.block_size - 1);
 482
 483         if (info.journal_blocks == 0)
 484                 info.journal_blocks = compute_journal_blocks();
 485
 486         if (info.no_journal == 0)
 487                 info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL;
 488         else
 489                 info.journal_blocks = 0;
 490
 491         if (info.blocks_per_group <= 0)
 492                 info.blocks_per_group = compute_blocks_per_group();
 493
 494         if (info.inodes <= 0)
 495                 info.inodes = compute_inodes();
 496
 497         if (info.inode_size <= 0)
 498                 info.inode_size = 256;
 499
 500         if (info.label == NULL)
 501                 info.label = "";
 502
 503         info.inodes_per_group = compute_inodes_per_group();
 504
 505         info.feat_compat |=
 506                         EXT4_FEATURE_COMPAT_RESIZE_INODE;
 507
 508         info.feat_ro_compat |=
 509                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER |
 510                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE |
 511                         EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 512
 513         info.feat_incompat |=
 514                         EXT4_FEATURE_INCOMPAT_EXTENTS |
 515                         EXT4_FEATURE_INCOMPAT_FILETYPE;
 516
 517
 518         info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks();
 519
 520         printf("Creating filesystem with parameters:\n");
 521         printf("    Size: %llu\n", info.len);
 522         printf("    Block size: %d\n", info.block_size);
 523         printf("    Blocks per group: %d\n", info.blocks_per_group);
 524         printf("    Inodes per group: %d\n", info.inodes_per_group);
 525         printf("    Inode size: %d\n", info.inode_size);
 526         printf("    Journal blocks: %d\n", info.journal_blocks);
 527         printf("    Label: %s\n", info.label);
 528
 529         ext4_create_fs_aux_info();
 530
 531         printf("    Blocks: %llu\n", aux_info.len_blocks);
 532         printf("    Block groups: %d\n", aux_info.groups);
 533         printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 534
 535         info.sparse_file = sparse_file_new(info.block_size, info.len);
 536
 537         block_allocator_init();
 538
 539         ext4_fill_in_sb();
 540
 541         if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
 542                 error("failed to reserve first 10 inodes");
 543
 544         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 545                 ext4_create_journal_inode();
 546
 547         if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
 548                 ext4_create_resize_inode();
 549
 550 #ifdef USE_MINGW
 551         // Windows needs only 'create an empty fs image' functionality
 552         assert(!directory);
 553         root_inode_num = build_default_directory_structure();
 554 #else
 555         if (directory)
 556                 root_inode_num = build_directory_structure(directory, mountpoint, 0,
 557                         fs_config_func, sehnd, verbose);
 558         else
 559                 root_inode_num = build_default_directory_structure();
 560 #endif
 561
 562         root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 563         inode_set_permissions(root_inode_num, root_mode, 0, 0, 0);
 564
 565 #ifndef USE_MINGW
 566         if (sehnd) {
 567                 char *secontext = NULL;
 568
 569                 if (selabel_lookup(sehnd, &secontext, mountpoint, S_IFDIR) < 0) {
 570                         error("cannot lookup security context for %s", mountpoint);
 571                 }
 572                 if (secontext) {
 573                         if (verbose) {
 574                                 printf("Labeling %s as %s\n", mountpoint, secontext);
 575                         }
 576                         inode_set_selinux(root_inode_num, secontext);
 577                 }
 578                 freecon(secontext);
 579         }
 580 #endif
 581
 582         ext4_update_free();
 583
 584         ext4_queue_sb();
 585
 586         printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
 587                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 588                         aux_info.sb->s_inodes_count,
 589                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 590                         aux_info.sb->s_blocks_count_lo);
 591
 592         if (wipe)
 593                 wipe_block_device(fd, info.len);
 594
 595         write_ext4_image(fd, gzip, sparse, crc);
 596
 597         sparse_file_destroy(info.sparse_file);
 598         info.sparse_file = NULL;
 599
 600         free(mountpoint);
 601         free(directory);
 602
 603         return 0;
 604 }