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