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