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                         unsigned int mode = 0;
 151                         unsigned int uid = 0;
 152                         unsigned int gid = 0;
 153                         int dir = S_ISDIR(stat.st_mode);
 154                         if (fs_config_func(dentries[i].path, dir, &uid, &gid, &mode, &capabilities)) {
 155                                 dentries[i].mode = mode;
 156                                 dentries[i].uid = uid;
 157                                 dentries[i].gid = gid;
 158                                 dentries[i].capabilities = capabilities;
 159                         }
 160                 }
 161
 162                 if (S_ISREG(stat.st_mode)) {
 163                         dentries[i].file_type = EXT4_FT_REG_FILE;
 164                 } else if (S_ISDIR(stat.st_mode)) {
 165                         dentries[i].file_type = EXT4_FT_DIR;
 166                         dirs++;
 167                 } else if (S_ISCHR(stat.st_mode)) {
 168                         dentries[i].file_type = EXT4_FT_CHRDEV;
 169                 } else if (S_ISBLK(stat.st_mode)) {
 170                         dentries[i].file_type = EXT4_FT_BLKDEV;
 171                 } else if (S_ISFIFO(stat.st_mode)) {
 172                         dentries[i].file_type = EXT4_FT_FIFO;
 173                 } else if (S_ISSOCK(stat.st_mode)) {
 174                         dentries[i].file_type = EXT4_FT_SOCK;
 175                 } else if (S_ISLNK(stat.st_mode)) {
 176                         dentries[i].file_type = EXT4_FT_SYMLINK;
 177                         dentries[i].link = calloc(info.block_size, 1);
 178                         readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
 179                 } else {
 180                         error("unknown file type on %s", dentries[i].path);
 181                         i--;
 182                         entries--;
 183                 }
 184         }
 185         free(namelist);
 186
 187         if (needs_lost_and_found) {
 188                 /* insert a lost+found directory at the beginning of the dentries */
 189                 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry));
 190                 memset(tmp, 0, sizeof(struct dentry));
 191                 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry));
 192                 dentries = tmp;
 193
 194                 dentries[0].filename = strdup("lost+found");
 195                 asprintf(&dentries[0].path, "%slost+found", dir_path);
 196                 dentries[0].full_path = NULL;
 197                 dentries[0].size = 0;
 198                 dentries[0].mode = S_IRWXU;
 199                 dentries[0].file_type = EXT4_FT_DIR;
 200                 dentries[0].uid = 0;
 201                 dentries[0].gid = 0;
 202                 entries++;
 203                 dirs++;
 204         }
 205
 206         inode = make_directory(dir_inode, entries, dentries, dirs);
 207
 208         for (i = 0; i < entries; i++) {
 209                 if (dentries[i].file_type == EXT4_FT_REG_FILE) {
 210                         entry_inode = make_file(dentries[i].full_path, dentries[i].size);
 211                 } else if (dentries[i].file_type == EXT4_FT_DIR) {
 212                         char *subdir_full_path = NULL;
 213                         char *subdir_dir_path;
 214                         if (dentries[i].full_path) {
 215                                 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path);
 216                                 if (ret < 0)
 217                                         critical_error_errno("asprintf");
 218                         }
 219                         ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path);
 220                         if (ret < 0)
 221                                 critical_error_errno("asprintf");
 222                         entry_inode = build_directory_structure(subdir_full_path,
 223                                         subdir_dir_path, inode, fs_config_func, verbose, fixed_time);
 224                         free(subdir_full_path);
 225                         free(subdir_dir_path);
 226                 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
 227                         entry_inode = make_link(dentries[i].link);
 228                 } else if (dentries[i].file_type == EXT4_FT_CHRDEV ||
 229                            dentries[i].file_type == EXT4_FT_BLKDEV ||
 230                            dentries[i].file_type == EXT4_FT_SOCK ||
 231                            dentries[i].file_type == EXT4_FT_FIFO) {
 232                         entry_inode = make_special(dentries[i].full_path);
 233                 } else {
 234                         error("unknown file type on %s", dentries[i].path);
 235                         entry_inode = 0;
 236                 }
 237                 *dentries[i].inode = entry_inode;
 238
 239                 ret = inode_set_permissions(entry_inode, dentries[i].mode,
 240                         dentries[i].uid, dentries[i].gid,
 241                         dentries[i].mtime);
 242                 if (ret)
 243                         error("failed to set permissions on %s\n", dentries[i].path);
 244
 245                 ret = inode_set_capabilities(entry_inode, dentries[i].capabilities);
 246                 if (ret)
 247                         error("failed to set capability on %s\n", dentries[i].path);
 248
 249                 free(dentries[i].path);
 250                 free(dentries[i].full_path);
 251                 free(dentries[i].link);
 252                 free((void *)dentries[i].filename);
 253         }
 254
 255         free(dentries);
 256         return inode;
 257 }
 258 #endif
 259
 260 static u32 compute_block_size()
 261 {
 262         return 4096;
 263 }
 264
 265 static u32 compute_journal_blocks()
 266 {
 267         u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
 268         if (journal_blocks < 1024)
 269                 journal_blocks = 1024;
 270         if (journal_blocks > 32768)
 271                 journal_blocks = 32768;
 272         return journal_blocks;
 273 }
 274
 275 static u32 compute_blocks_per_group()
 276 {
 277         return info.block_size * 8;
 278 }
 279
 280 static u32 compute_inodes()
 281 {
 282         return DIV_ROUND_UP(info.len, info.block_size) / 4;
 283 }
 284
 285 static u32 compute_inodes_per_group()
 286 {
 287         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 288         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 289         u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
 290         inodes = EXT4_ALIGN(inodes, (info.block_size / info.inode_size));
 291
 292         /* After properly rounding up the number of inodes/group,
 293          * make sure to update the total inodes field in the info struct.
 294          */
 295         info.inodes = inodes * block_groups;
 296
 297         return inodes;
 298 }
 299
 300 static u32 compute_bg_desc_reserve_blocks()
 301 {
 302         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 303         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 304         u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
 305                         info.block_size);
 306
 307         u32 bg_desc_reserve_blocks =
 308                         DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
 309                                         info.block_size) - bg_desc_blocks;
 310
 311         if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
 312                 bg_desc_reserve_blocks = info.block_size / sizeof(u32);
 313
 314         return bg_desc_reserve_blocks;
 315 }
 316
 317 void reset_ext4fs_info() {
 318         // Reset all the global data structures used by make_ext4fs so it
 319         // can be called again.
 320         memset(&info, 0, sizeof(info));
 321         memset(&aux_info, 0, sizeof(aux_info));
 322
 323         if (ext4_sparse_file) {
 324                 sparse_file_destroy(ext4_sparse_file);
 325                 ext4_sparse_file = NULL;
 326         }
 327 }
 328
 329 int make_ext4fs_sparse_fd(int fd, long long len,
 330                                 const char *mountpoint)
 331 {
 332         reset_ext4fs_info();
 333         info.len = len;
 334
 335         return make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 1, 0, 0, 0, -1, NULL);
 336 }
 337
 338 int make_ext4fs(const char *filename, long long len,
 339                                 const char *mountpoint)
 340 {
 341         int fd;
 342         int status;
 343
 344         reset_ext4fs_info();
 345         info.len = len;
 346
 347         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 348         if (fd < 0) {
 349                 error_errno("open");
 350                 return EXIT_FAILURE;
 351         }
 352
 353         status = make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 0, 0, 1, 0, -1, NULL);
 354         close(fd);
 355
 356         return status;
 357 }
 358
 359 /* return a newly-malloc'd string that is a copy of str.  The new string
 360    is guaranteed to have a trailing slash.  If absolute is true, the new string
 361    is also guaranteed to have a leading slash.
 362 */
 363 static char *canonicalize_slashes(const char *str, bool absolute)
 364 {
 365         char *ret;
 366         int len = strlen(str);
 367         int newlen = len;
 368         char *ptr;
 369
 370         if (len == 0) {
 371                 if (absolute)
 372                         return strdup("/");
 373                 else
 374                         return strdup("");
 375         }
 376
 377         if (str[0] != '/' && absolute) {
 378                 newlen++;
 379         }
 380         if (str[len - 1] != '/') {
 381                 newlen++;
 382         }
 383         ret = malloc(newlen + 1);
 384         if (!ret) {
 385                 critical_error("malloc");
 386         }
 387
 388         ptr = ret;
 389         if (str[0] != '/' && absolute) {
 390                 *ptr++ = '/';
 391         }
 392
 393         strcpy(ptr, str);
 394         ptr += len;
 395
 396         if (str[len - 1] != '/') {
 397                 *ptr++ = '/';
 398         }
 399
 400         if (ptr != ret + newlen) {
 401                 critical_error("assertion failed\n");
 402         }
 403
 404         *ptr = '\0';
 405
 406         return ret;
 407 }
 408
 409 static char *canonicalize_abs_slashes(const char *str)
 410 {
 411         return canonicalize_slashes(str, true);
 412 }
 413
 414 static char *canonicalize_rel_slashes(const char *str)
 415 {
 416         return canonicalize_slashes(str, false);
 417 }
 418
 419 int make_ext4fs_internal(int fd, const char *_directory,
 420                                                  const char *_mountpoint, fs_config_func_t fs_config_func, int gzip,
 421                                                  int sparse, int crc, int wipe,
 422                                                  int verbose, time_t fixed_time,
 423                                                  FILE* block_list_file)
 424 {
 425         u32 root_inode_num;
 426         u16 root_mode;
 427         char *mountpoint;
 428         char *directory = NULL;
 429
 430         if (setjmp(setjmp_env))
 431                 return EXIT_FAILURE; /* Handle a call to longjmp() */
 432
 433         if (_mountpoint == NULL) {
 434                 mountpoint = strdup("");
 435         } else {
 436                 mountpoint = canonicalize_abs_slashes(_mountpoint);
 437         }
 438
 439         if (_directory) {
 440                 directory = canonicalize_rel_slashes(_directory);
 441         }
 442
 443         if (info.len <= 0)
 444                 info.len = get_file_size(fd);
 445
 446         if (info.len <= 0) {
 447                 fprintf(stderr, "Need size of filesystem\n");
 448                 return EXIT_FAILURE;
 449         }
 450
 451         if (info.block_size <= 0)
 452                 info.block_size = compute_block_size();
 453
 454         /* Round down the filesystem length to be a multiple of the block size */
 455         info.len &= ~((u64)info.block_size - 1);
 456
 457         if (info.journal_blocks == 0)
 458                 info.journal_blocks = compute_journal_blocks();
 459
 460         if (info.no_journal == 0)
 461                 info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL;
 462         else
 463                 info.journal_blocks = 0;
 464
 465         if (info.blocks_per_group <= 0)
 466                 info.blocks_per_group = compute_blocks_per_group();
 467
 468         if (info.inodes <= 0)
 469                 info.inodes = compute_inodes();
 470
 471         if (info.inode_size <= 0)
 472                 info.inode_size = 256;
 473
 474         if (info.label == NULL)
 475                 info.label = "";
 476
 477         info.inodes_per_group = compute_inodes_per_group();
 478
 479         info.feat_compat |=
 480                         EXT4_FEATURE_COMPAT_RESIZE_INODE |
 481                         EXT4_FEATURE_COMPAT_EXT_ATTR;
 482
 483         info.feat_ro_compat |=
 484                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER |
 485                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE |
 486                         EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 487
 488         info.feat_incompat |=
 489                         EXT4_FEATURE_INCOMPAT_EXTENTS |
 490                         EXT4_FEATURE_INCOMPAT_FILETYPE;
 491
 492
 493         info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks();
 494
 495         printf("Creating filesystem with parameters:\n");
 496         printf("    Size: %"PRIu64"\n", info.len);
 497         printf("    Block size: %d\n", info.block_size);
 498         printf("    Blocks per group: %d\n", info.blocks_per_group);
 499         printf("    Inodes per group: %d\n", info.inodes_per_group);
 500         printf("    Inode size: %d\n", info.inode_size);
 501         printf("    Journal blocks: %d\n", info.journal_blocks);
 502         printf("    Label: %s\n", info.label);
 503
 504         ext4_create_fs_aux_info();
 505
 506         printf("    Blocks: %"PRIu64"\n", aux_info.len_blocks);
 507         printf("    Block groups: %d\n", aux_info.groups);
 508         printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 509
 510         ext4_sparse_file = sparse_file_new(info.block_size, info.len);
 511
 512         block_allocator_init();
 513
 514         ext4_fill_in_sb();
 515
 516         if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
 517                 error("failed to reserve first 10 inodes");
 518
 519         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 520                 ext4_create_journal_inode();
 521
 522         if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
 523                 ext4_create_resize_inode();
 524
 525 #ifdef USE_MINGW
 526         // Windows needs only 'create an empty fs image' functionality
 527         assert(!directory);
 528         root_inode_num = build_default_directory_structure(mountpoint);
 529 #else
 530         if (directory)
 531                 root_inode_num = build_directory_structure(directory, mountpoint, 0,
 532                         fs_config_func, verbose, fixed_time);
 533         else
 534                 root_inode_num = build_default_directory_structure(mountpoint);
 535 #endif
 536
 537         root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 538         inode_set_permissions(root_inode_num, root_mode, 0, 0, 0);
 539
 540         ext4_update_free();
 541
 542         ext4_queue_sb();
 543
 544         if (block_list_file) {
 545                 size_t dirlen = directory ? strlen(directory) : 0;
 546                 struct block_allocation* p = get_saved_allocation_chain();
 547                 while (p) {
 548                         if (directory && strncmp(p->filename, directory, dirlen) == 0) {
 549                                 // substitute mountpoint for the leading directory in the filename, in the output file
 550                                 fprintf(block_list_file, "%s%s", mountpoint, p->filename + dirlen);
 551                         } else {
 552                                 fprintf(block_list_file, "%s", p->filename);
 553                         }
 554                         print_blocks(block_list_file, p);
 555                         struct block_allocation* pn = p->next;
 556                         free_alloc(p);
 557                         p = pn;
 558                 }
 559         }
 560
 561         printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
 562                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 563                         aux_info.sb->s_inodes_count,
 564                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 565                         aux_info.sb->s_blocks_count_lo);
 566
 567         if (wipe && WIPE_IS_SUPPORTED) {
 568                 wipe_block_device(fd, info.len);
 569         }
 570
 571         write_ext4_image(fd, gzip, sparse, crc);
 572
 573         sparse_file_destroy(ext4_sparse_file);
 574         ext4_sparse_file = NULL;
 575
 576         free(mountpoint);
 577         free(directory);
 578
 579         return 0;
 580 }