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