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 <inttypes.h>
  30 #include <libgen.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35 #include <sys/stat.h>
  36 #include <sys/types.h>
  37
  38 #ifndef USE_MINGW
  39
  40 #define O_BINARY 0
  41
  42 #endif
  43
  44 /* TODO: Not implemented:
  45    Allocating blocks in the same block group as the file inode
  46    Hash or binary tree directories
  47  */
  48
  49 static int filter_dot(const struct dirent *d)
  50 {
  51         return (strcmp(d->d_name, "..") && strcmp(d->d_name, "."));
  52 }
  53
  54 static u32 build_default_directory_structure(const char *dir_path)
  55 {
  56         u32 inode;
  57         u32 root_inode;
  58         struct dentry dentries = {
  59                         .filename = "lost+found",
  60                         .file_type = EXT4_FT_DIR,
  61                         .mode = S_IRWXU,
  62                         .uid = 0,
  63                         .gid = 0,
  64                         .mtime = 0,
  65         };
  66         root_inode = make_directory(0, 1, &dentries, 1);
  67         inode = make_directory(root_inode, 0, NULL, 0);
  68         *dentries.inode = inode;
  69         inode_set_permissions(inode, dentries.mode,
  70                 dentries.uid, dentries.gid, dentries.mtime);
  71
  72         return root_inode;
  73 }
  74
  75 #ifndef USE_MINGW
  76 /* Read a local directory and create the same tree in the generated filesystem.
  77    Calls itself recursively with each directory in the given directory.
  78    full_path is an absolute or relative path, with a trailing slash, to the
  79    directory on disk that should be copied, or NULL if this is a directory
  80    that does not exist on disk (e.g. lost+found).
  81    dir_path is an absolute path, with trailing slash, to the same directory
  82    if the image were mounted at the specified mount point */
  83 static u32 build_directory_structure(const char *full_path, const char *dir_path,
  84                 u32 dir_inode, fs_config_func_t fs_config_func,
  85                 int verbose, time_t fixed_time)
  86 {
  87         int entries = 0;
  88         struct dentry *dentries;
  89         struct dirent **namelist = NULL;
  90         struct stat stat;
  91         int ret;
  92         int i;
  93         u32 inode;
  94         u32 entry_inode;
  95         u32 dirs = 0;
  96         bool needs_lost_and_found = false;
  97
  98         if (full_path) {
  99                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
 100                 if (entries < 0) {
 101 #ifdef __GLIBC__
 102                         /* The scandir function implemented in glibc has a bug that makes it
 103                            erroneously fail with ENOMEM under certain circumstances.
 104                            As a workaround we can retry the scandir call with the same arguments.
 105                            GLIBC BZ: https://sourceware.org/bugzilla/show_bug.cgi?id=17804 */
 106                         if (errno == ENOMEM)
 107                                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
 108 #endif
 109                         if (entries < 0) {
 110                                 error_errno("scandir");
 111                                 return EXT4_ALLOCATE_FAILED;
 112                         }
 113                 }
 114         }
 115
 116         if (dir_inode == 0) {
 117                 /* root directory, check if lost+found already exists */
 118                 for (i = 0; i < entries; i++)
 119                         if (strcmp(namelist[i]->d_name, "lost+found") == 0)
 120                                 break;
 121                 if (i == entries)
 122                         needs_lost_and_found = true;
 123         }
 124
 125         dentries = calloc(entries, sizeof(struct dentry));
 126         if (dentries == NULL)
 127                 critical_error_errno("malloc");
 128
 129         for (i = 0; i < entries; i++) {
 130                 dentries[i].filename = strdup(namelist[i]->d_name);
 131                 if (dentries[i].filename == NULL)
 132                         critical_error_errno("strdup");
 133
 134                 asprintf(&dentries[i].path, "%s%s", dir_path, namelist[i]->d_name);
 135                 asprintf(&dentries[i].full_path, "%s%s", full_path, namelist[i]->d_name);
 136
 137                 free(namelist[i]);
 138
 139                 ret = lstat(dentries[i].full_path, &stat);
 140                 if (ret < 0) {
 141                         error_errno("lstat");
 142                         i--;
 143                         entries--;
 144                         continue;
 145                 }
 146
 147                 dentries[i].size = stat.st_size;
 148                 dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO);
 149                 if (fixed_time == -1) {
 150                         dentries[i].mtime = stat.st_mtime;
 151                 } else {
 152                         dentries[i].mtime = fixed_time;
 153                 }
 154                 uint64_t capabilities;
 155                 if (fs_config_func != NULL) {
 156 #ifdef ANDROID
 157                         unsigned int mode = 0;
 158                         unsigned int uid = 0;
 159                         unsigned int gid = 0;
 160                         int dir = S_ISDIR(stat.st_mode);
 161                         fs_config_func(dentries[i].path, dir, &uid, &gid, &mode, &capabilities);
 162                         dentries[i].mode = mode;
 163                         dentries[i].uid = uid;
 164                         dentries[i].gid = gid;
 165                         dentries[i].capabilities = capabilities;
 166 #else
 167                         error("can't set android permissions - built without android support");
 168 #endif
 169                 }
 170
 171                 if (S_ISREG(stat.st_mode)) {
 172                         dentries[i].file_type = EXT4_FT_REG_FILE;
 173                 } else if (S_ISDIR(stat.st_mode)) {
 174                         dentries[i].file_type = EXT4_FT_DIR;
 175                         dirs++;
 176                 } else if (S_ISCHR(stat.st_mode)) {
 177                         dentries[i].file_type = EXT4_FT_CHRDEV;
 178                 } else if (S_ISBLK(stat.st_mode)) {
 179                         dentries[i].file_type = EXT4_FT_BLKDEV;
 180                 } else if (S_ISFIFO(stat.st_mode)) {
 181                         dentries[i].file_type = EXT4_FT_FIFO;
 182                 } else if (S_ISSOCK(stat.st_mode)) {
 183                         dentries[i].file_type = EXT4_FT_SOCK;
 184                 } else if (S_ISLNK(stat.st_mode)) {
 185                         dentries[i].file_type = EXT4_FT_SYMLINK;
 186                         dentries[i].link = calloc(info.block_size, 1);
 187                         readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
 188                 } else {
 189                         error("unknown file type on %s", dentries[i].path);
 190                         i--;
 191                         entries--;
 192                 }
 193         }
 194         free(namelist);
 195
 196         if (needs_lost_and_found) {
 197                 /* insert a lost+found directory at the beginning of the dentries */
 198                 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry));
 199                 memset(tmp, 0, sizeof(struct dentry));
 200                 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry));
 201                 dentries = tmp;
 202
 203                 dentries[0].filename = strdup("lost+found");
 204                 asprintf(&dentries[0].path, "%slost+found", dir_path);
 205                 dentries[0].full_path = NULL;
 206                 dentries[0].size = 0;
 207                 dentries[0].mode = S_IRWXU;
 208                 dentries[0].file_type = EXT4_FT_DIR;
 209                 dentries[0].uid = 0;
 210                 dentries[0].gid = 0;
 211                 entries++;
 212                 dirs++;
 213         }
 214
 215         inode = make_directory(dir_inode, entries, dentries, dirs);
 216
 217         for (i = 0; i < entries; i++) {
 218                 if (dentries[i].file_type == EXT4_FT_REG_FILE) {
 219                         entry_inode = make_file(dentries[i].full_path, dentries[i].size);
 220                 } else if (dentries[i].file_type == EXT4_FT_DIR) {
 221                         char *subdir_full_path = NULL;
 222                         char *subdir_dir_path;
 223                         if (dentries[i].full_path) {
 224                                 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path);
 225                                 if (ret < 0)
 226                                         critical_error_errno("asprintf");
 227                         }
 228                         ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path);
 229                         if (ret < 0)
 230                                 critical_error_errno("asprintf");
 231                         entry_inode = build_directory_structure(subdir_full_path,
 232                                         subdir_dir_path, inode, fs_config_func, verbose, fixed_time);
 233                         free(subdir_full_path);
 234                         free(subdir_dir_path);
 235                 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
 236                         entry_inode = make_link(dentries[i].link);
 237                 } else if (dentries[i].file_type == EXT4_FT_CHRDEV ||
 238                            dentries[i].file_type == EXT4_FT_BLKDEV ||
 239                            dentries[i].file_type == EXT4_FT_SOCK ||
 240                            dentries[i].file_type == EXT4_FT_FIFO) {
 241                         entry_inode = make_special(dentries[i].full_path);
 242                 } else {
 243                         error("unknown file type on %s", dentries[i].path);
 244                         entry_inode = 0;
 245                 }
 246                 *dentries[i].inode = entry_inode;
 247
 248                 ret = inode_set_permissions(entry_inode, dentries[i].mode,
 249                         dentries[i].uid, dentries[i].gid,
 250                         dentries[i].mtime);
 251                 if (ret)
 252                         error("failed to set permissions on %s\n", dentries[i].path);
 253
 254                 /*
 255                  * It's important to call inode_set_selinux() before
 256                  * inode_set_capabilities(). Extended attributes need to
 257                  * be stored sorted order, and we guarantee this by making
 258                  * the calls in the proper order.
 259                  * Please see xattr_assert_sane() in contents.c
 260                  */
 261                 ret = inode_set_selinux(entry_inode, dentries[i].secon);
 262                 if (ret)
 263                         error("failed to set SELinux context on %s\n", dentries[i].path);
 264                 ret = inode_set_capabilities(entry_inode, dentries[i].capabilities);
 265                 if (ret)
 266                         error("failed to set capability on %s\n", dentries[i].path);
 267
 268                 free(dentries[i].path);
 269                 free(dentries[i].full_path);
 270                 free(dentries[i].link);
 271                 free((void *)dentries[i].filename);
 272                 free(dentries[i].secon);
 273         }
 274
 275         free(dentries);
 276         return inode;
 277 }
 278 #endif
 279
 280 static u32 compute_block_size()
 281 {
 282         return 4096;
 283 }
 284
 285 static u32 compute_journal_blocks()
 286 {
 287         u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
 288         if (journal_blocks < 1024)
 289                 journal_blocks = 1024;
 290         if (journal_blocks > 32768)
 291                 journal_blocks = 32768;
 292         return journal_blocks;
 293 }
 294
 295 static u32 compute_blocks_per_group()
 296 {
 297         return info.block_size * 8;
 298 }
 299
 300 static u32 compute_inodes()
 301 {
 302         return DIV_ROUND_UP(info.len, info.block_size) / 4;
 303 }
 304
 305 static u32 compute_inodes_per_group()
 306 {
 307         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 308         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 309         u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
 310         inodes = EXT4_ALIGN(inodes, (info.block_size / info.inode_size));
 311
 312         /* After properly rounding up the number of inodes/group,
 313          * make sure to update the total inodes field in the info struct.
 314          */
 315         info.inodes = inodes * block_groups;
 316
 317         return inodes;
 318 }
 319
 320 static u32 compute_bg_desc_reserve_blocks()
 321 {
 322         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 323         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 324         u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
 325                         info.block_size);
 326
 327         u32 bg_desc_reserve_blocks =
 328                         DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
 329                                         info.block_size) - bg_desc_blocks;
 330
 331         if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
 332                 bg_desc_reserve_blocks = info.block_size / sizeof(u32);
 333
 334         return bg_desc_reserve_blocks;
 335 }
 336
 337 void reset_ext4fs_info() {
 338         // Reset all the global data structures used by make_ext4fs so it
 339         // can be called again.
 340         memset(&info, 0, sizeof(info));
 341         memset(&aux_info, 0, sizeof(aux_info));
 342
 343         if (ext4_sparse_file) {
 344                 sparse_file_destroy(ext4_sparse_file);
 345                 ext4_sparse_file = NULL;
 346         }
 347 }
 348
 349 int make_ext4fs_sparse_fd(int fd, long long len,
 350                                 const char *mountpoint)
 351 {
 352         reset_ext4fs_info();
 353         info.len = len;
 354
 355         return make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 1, 0, 0, 0, -1, NULL);
 356 }
 357
 358 int make_ext4fs(const char *filename, long long len,
 359                                 const char *mountpoint)
 360 {
 361         int fd;
 362         int status;
 363
 364         reset_ext4fs_info();
 365         info.len = len;
 366
 367         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
 368         if (fd < 0) {
 369                 error_errno("open");
 370                 return EXIT_FAILURE;
 371         }
 372
 373         status = make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 0, 0, 1, 0, -1, NULL);
 374         close(fd);
 375
 376         return status;
 377 }
 378
 379 /* return a newly-malloc'd string that is a copy of str.  The new string
 380    is guaranteed to have a trailing slash.  If absolute is true, the new string
 381    is also guaranteed to have a leading slash.
 382 */
 383 static char *canonicalize_slashes(const char *str, bool absolute)
 384 {
 385         char *ret;
 386         int len = strlen(str);
 387         int newlen = len;
 388         char *ptr;
 389
 390         if (len == 0) {
 391                 if (absolute)
 392                         return strdup("/");
 393                 else
 394                         return strdup("");
 395         }
 396
 397         if (str[0] != '/' && absolute) {
 398                 newlen++;
 399         }
 400         if (str[len - 1] != '/') {
 401                 newlen++;
 402         }
 403         ret = malloc(newlen + 1);
 404         if (!ret) {
 405                 critical_error("malloc");
 406         }
 407
 408         ptr = ret;
 409         if (str[0] != '/' && absolute) {
 410                 *ptr++ = '/';
 411         }
 412
 413         strcpy(ptr, str);
 414         ptr += len;
 415
 416         if (str[len - 1] != '/') {
 417                 *ptr++ = '/';
 418         }
 419
 420         if (ptr != ret + newlen) {
 421                 critical_error("assertion failed\n");
 422         }
 423
 424         *ptr = '\0';
 425
 426         return ret;
 427 }
 428
 429 static char *canonicalize_abs_slashes(const char *str)
 430 {
 431         return canonicalize_slashes(str, true);
 432 }
 433
 434 static char *canonicalize_rel_slashes(const char *str)
 435 {
 436         return canonicalize_slashes(str, false);
 437 }
 438
 439 int make_ext4fs_internal(int fd, const char *_directory,
 440                                                  const char *_mountpoint, fs_config_func_t fs_config_func, int gzip,
 441                                                  int sparse, int crc, int wipe,
 442                                                  int verbose, time_t fixed_time,
 443                                                  FILE* block_list_file)
 444 {
 445         u32 root_inode_num;
 446         u16 root_mode;
 447         char *mountpoint;
 448         char *directory = NULL;
 449
 450         if (setjmp(setjmp_env))
 451                 return EXIT_FAILURE; /* Handle a call to longjmp() */
 452
 453         if (_mountpoint == NULL) {
 454                 mountpoint = strdup("");
 455         } else {
 456                 mountpoint = canonicalize_abs_slashes(_mountpoint);
 457         }
 458
 459         if (_directory) {
 460                 directory = canonicalize_rel_slashes(_directory);
 461         }
 462
 463         if (info.len <= 0)
 464                 info.len = get_file_size(fd);
 465
 466         if (info.len <= 0) {
 467                 fprintf(stderr, "Need size of filesystem\n");
 468                 return EXIT_FAILURE;
 469         }
 470
 471         if (info.block_size <= 0)
 472                 info.block_size = compute_block_size();
 473
 474         /* Round down the filesystem length to be a multiple of the block size */
 475         info.len &= ~((u64)info.block_size - 1);
 476
 477         if (info.journal_blocks == 0)
 478                 info.journal_blocks = compute_journal_blocks();
 479
 480         if (info.no_journal == 0)
 481                 info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL;
 482         else
 483                 info.journal_blocks = 0;
 484
 485         if (info.blocks_per_group <= 0)
 486                 info.blocks_per_group = compute_blocks_per_group();
 487
 488         if (info.inodes <= 0)
 489                 info.inodes = compute_inodes();
 490
 491         if (info.inode_size <= 0)
 492                 info.inode_size = 256;
 493
 494         if (info.label == NULL)
 495                 info.label = "";
 496
 497         info.inodes_per_group = compute_inodes_per_group();
 498
 499         info.feat_compat |=
 500                         EXT4_FEATURE_COMPAT_RESIZE_INODE |
 501                         EXT4_FEATURE_COMPAT_EXT_ATTR;
 502
 503         info.feat_ro_compat |=
 504                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER |
 505                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE |
 506                         EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 507
 508         info.feat_incompat |=
 509                         EXT4_FEATURE_INCOMPAT_EXTENTS |
 510                         EXT4_FEATURE_INCOMPAT_FILETYPE;
 511
 512
 513         info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks();
 514
 515         printf("Creating filesystem with parameters:\n");
 516         printf("    Size: %"PRIu64"\n", info.len);
 517         printf("    Block size: %d\n", info.block_size);
 518         printf("    Blocks per group: %d\n", info.blocks_per_group);
 519         printf("    Inodes per group: %d\n", info.inodes_per_group);
 520         printf("    Inode size: %d\n", info.inode_size);
 521         printf("    Journal blocks: %d\n", info.journal_blocks);
 522         printf("    Label: %s\n", info.label);
 523
 524         ext4_create_fs_aux_info();
 525
 526         printf("    Blocks: %"PRIu64"\n", aux_info.len_blocks);
 527         printf("    Block groups: %d\n", aux_info.groups);
 528         printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 529
 530         ext4_sparse_file = sparse_file_new(info.block_size, info.len);
 531
 532         block_allocator_init();
 533
 534         ext4_fill_in_sb();
 535
 536         if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
 537                 error("failed to reserve first 10 inodes");
 538
 539         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 540                 ext4_create_journal_inode();
 541
 542         if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
 543                 ext4_create_resize_inode();
 544
 545 #ifdef USE_MINGW
 546         // Windows needs only 'create an empty fs image' functionality
 547         assert(!directory);
 548         root_inode_num = build_default_directory_structure(mountpoint);
 549 #else
 550         if (directory)
 551                 root_inode_num = build_directory_structure(directory, mountpoint, 0,
 552                         fs_config_func, verbose, fixed_time);
 553         else
 554                 root_inode_num = build_default_directory_structure(mountpoint);
 555 #endif
 556
 557         root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 558         inode_set_permissions(root_inode_num, root_mode, 0, 0, 0);
 559
 560         ext4_update_free();
 561
 562         ext4_queue_sb();
 563
 564         if (block_list_file) {
 565                 size_t dirlen = directory ? strlen(directory) : 0;
 566                 struct block_allocation* p = get_saved_allocation_chain();
 567                 while (p) {
 568                         if (directory && strncmp(p->filename, directory, dirlen) == 0) {
 569                                 // substitute mountpoint for the leading directory in the filename, in the output file
 570                                 fprintf(block_list_file, "%s%s", mountpoint, p->filename + dirlen);
 571                         } else {
 572                                 fprintf(block_list_file, "%s", p->filename);
 573                         }
 574                         print_blocks(block_list_file, p);
 575                         struct block_allocation* pn = p->next;
 576                         free_alloc(p);
 577                         p = pn;
 578                 }
 579         }
 580
 581         printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
 582                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 583                         aux_info.sb->s_inodes_count,
 584                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 585                         aux_info.sb->s_blocks_count_lo);
 586
 587         if (wipe && WIPE_IS_SUPPORTED) {
 588                 wipe_block_device(fd, info.len);
 589         }
 590
 591         write_ext4_image(fd, gzip, sparse, crc);
 592
 593         sparse_file_destroy(ext4_sparse_file);
 594         ext4_sparse_file = NULL;
 595
 596         free(mountpoint);
 597         free(directory);
 598
 599         return 0;
 600 }