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 "ext4_utils.h"
  18 #include "allocate.h"
  19 #include "contents.h"
  20 #include "uuid.h"
  21 #include "wipe.h"
  22
  23 #include <sparse/sparse.h>
  24
  25 #include <assert.h>
  26 #include <dirent.h>
  27 #include <fcntl.h>
  28 #include <inttypes.h>
  29 #include <libgen.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34 #include <sys/stat.h>
  35 #include <sys/types.h>
  36 #include <locale.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(time_t fixed_time)
  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 = (fixed_time != -1) ? fixed_time : 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         /* alphasort is locale-dependent; let's fix the locale to some sane value */
  92         setlocale(LC_COLLATE, "C");
  93
  94         if (full_path) {
  95                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
  96                 if (entries < 0) {
  97 #ifdef __GLIBC__
  98                         /* The scandir function implemented in glibc has a bug that makes it
  99                            erroneously fail with ENOMEM under certain circumstances.
 100                            As a workaround we can retry the scandir call with the same arguments.
 101                            GLIBC BZ: https://sourceware.org/bugzilla/show_bug.cgi?id=17804 */
 102                         if (errno == ENOMEM)
 103                                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
 104 #endif
 105                         if (entries < 0) {
 106                                 error_errno("scandir");
 107                                 return EXT4_ALLOCATE_FAILED;
 108                         }
 109                 }
 110         }
 111
 112         if (dir_inode == 0) {
 113                 /* root directory, check if lost+found already exists */
 114                 for (i = 0; i < entries; i++)
 115                         if (strcmp(namelist[i]->d_name, "lost+found") == 0)
 116                                 break;
 117                 if (i == entries)
 118                         needs_lost_and_found = true;
 119         }
 120
 121         dentries = calloc(entries, sizeof(struct dentry));
 122         if (dentries == NULL)
 123                 critical_error_errno("malloc");
 124
 125         for (i = 0; i < entries; i++) {
 126                 dentries[i].filename = strdup(namelist[i]->d_name);
 127                 if (dentries[i].filename == NULL)
 128                         critical_error_errno("strdup");
 129
 130                 asprintf(&dentries[i].path, "%s%s", dir_path, namelist[i]->d_name);
 131                 asprintf(&dentries[i].full_path, "%s%s", full_path, namelist[i]->d_name);
 132
 133                 free(namelist[i]);
 134
 135                 ret = lstat(dentries[i].full_path, &stat);
 136                 if (ret < 0) {
 137                         error_errno("lstat");
 138                         i--;
 139                         entries--;
 140                         continue;
 141                 }
 142
 143                 dentries[i].size = stat.st_size;
 144                 dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO);
 145                 if (fixed_time == -1) {
 146                         dentries[i].mtime = stat.st_mtime;
 147                 } else {
 148                         dentries[i].mtime = fixed_time;
 149                 }
 150                 uint64_t capabilities;
 151                 if (fs_config_func != NULL) {
 152                         unsigned int mode = 0;
 153                         unsigned int uid = 0;
 154                         unsigned int gid = 0;
 155                         int dir = S_ISDIR(stat.st_mode);
 156                         if (fs_config_func(dentries[i].path, dir, &uid, &gid, &mode, &capabilities)) {
 157                                 dentries[i].mode = mode;
 158                                 dentries[i].uid = uid;
 159                                 dentries[i].gid = gid;
 160                                 dentries[i].capabilities = capabilities;
 161                         }
 162                 }
 163
 164                 if (S_ISREG(stat.st_mode)) {
 165                         dentries[i].file_type = EXT4_FT_REG_FILE;
 166                 } else if (S_ISDIR(stat.st_mode)) {
 167                         dentries[i].file_type = EXT4_FT_DIR;
 168                         dirs++;
 169                 } else if (S_ISCHR(stat.st_mode)) {
 170                         dentries[i].file_type = EXT4_FT_CHRDEV;
 171                 } else if (S_ISBLK(stat.st_mode)) {
 172                         dentries[i].file_type = EXT4_FT_BLKDEV;
 173                 } else if (S_ISFIFO(stat.st_mode)) {
 174                         dentries[i].file_type = EXT4_FT_FIFO;
 175                 } else if (S_ISSOCK(stat.st_mode)) {
 176                         dentries[i].file_type = EXT4_FT_SOCK;
 177                 } else if (S_ISLNK(stat.st_mode)) {
 178                         dentries[i].file_type = EXT4_FT_SYMLINK;
 179                         dentries[i].link = calloc(info.block_size, 1);
 180                         readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
 181                 } else {
 182                         error("unknown file type on %s", dentries[i].path);
 183                         i--;
 184                         entries--;
 185                 }
 186         }
 187         free(namelist);
 188
 189         if (needs_lost_and_found) {
 190                 /* insert a lost+found directory at the beginning of the dentries */
 191                 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry));
 192                 memset(tmp, 0, sizeof(struct dentry));
 193                 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry));
 194                 dentries = tmp;
 195
 196                 dentries[0].filename = strdup("lost+found");
 197                 asprintf(&dentries[0].path, "%slost+found", dir_path);
 198                 dentries[0].full_path = NULL;
 199                 dentries[0].size = 0;
 200                 dentries[0].mode = S_IRWXU;
 201                 dentries[0].file_type = EXT4_FT_DIR;
 202                 dentries[0].uid = 0;
 203                 dentries[0].gid = 0;
 204                 entries++;
 205                 dirs++;
 206         }
 207
 208         inode = make_directory(dir_inode, entries, dentries, dirs);
 209
 210         for (i = 0; i < entries; i++) {
 211                 if (dentries[i].file_type == EXT4_FT_REG_FILE) {
 212                         entry_inode = make_file(dentries[i].full_path, dentries[i].size);
 213                 } else if (dentries[i].file_type == EXT4_FT_DIR) {
 214                         char *subdir_full_path = NULL;
 215                         char *subdir_dir_path;
 216                         if (dentries[i].full_path) {
 217                                 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path);
 218                                 if (ret < 0)
 219                                         critical_error_errno("asprintf");
 220                         }
 221                         ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path);
 222                         if (ret < 0)
 223                                 critical_error_errno("asprintf");
 224                         entry_inode = build_directory_structure(subdir_full_path,
 225                                         subdir_dir_path, inode, fs_config_func, verbose, fixed_time);
 226                         free(subdir_full_path);
 227                         free(subdir_dir_path);
 228                 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
 229                         entry_inode = make_link(dentries[i].link);
 230                 } else if (dentries[i].file_type == EXT4_FT_CHRDEV ||
 231                            dentries[i].file_type == EXT4_FT_BLKDEV ||
 232                            dentries[i].file_type == EXT4_FT_SOCK ||
 233                            dentries[i].file_type == EXT4_FT_FIFO) {
 234                         entry_inode = make_special(dentries[i].full_path);
 235                 } else {
 236                         error("unknown file type on %s", dentries[i].path);
 237                         entry_inode = 0;
 238                 }
 239                 *dentries[i].inode = entry_inode;
 240
 241                 ret = inode_set_permissions(entry_inode, dentries[i].mode,
 242                         dentries[i].uid, dentries[i].gid,
 243                         dentries[i].mtime);
 244                 if (ret)
 245                         error("failed to set permissions on %s\n", dentries[i].path);
 246
 247                 ret = inode_set_capabilities(entry_inode, dentries[i].capabilities);
 248                 if (ret)
 249                         error("failed to set capability on %s\n", dentries[i].path);
 250
 251                 free(dentries[i].path);
 252                 free(dentries[i].full_path);
 253                 free(dentries[i].link);
 254                 free((void *)dentries[i].filename);
 255         }
 256
 257         free(dentries);
 258         return inode;
 259 }
 260
 261 static u32 compute_block_size()
 262 {
 263         return 4096;
 264 }
 265
 266 static u32 compute_journal_blocks()
 267 {
 268         u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
 269         if (journal_blocks < 1024)
 270                 journal_blocks = 1024;
 271         if (journal_blocks > 32768)
 272                 journal_blocks = 32768;
 273         return journal_blocks;
 274 }
 275
 276 static u32 compute_blocks_per_group()
 277 {
 278         return info.block_size * 8;
 279 }
 280
 281 static u32 compute_inodes()
 282 {
 283         return DIV_ROUND_UP(info.len, info.block_size) / 4;
 284 }
 285
 286 static u32 compute_inodes_per_group()
 287 {
 288         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 289         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 290         u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
 291         inodes = EXT4_ALIGN(inodes, (info.block_size / info.inode_size));
 292
 293         /* After properly rounding up the number of inodes/group,
 294          * make sure to update the total inodes field in the info struct.
 295          */
 296         info.inodes = inodes * block_groups;
 297
 298         return inodes;
 299 }
 300
 301 static u32 compute_bg_desc_reserve_blocks()
 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 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
 306                         info.block_size);
 307
 308         u32 bg_desc_reserve_blocks =
 309                         DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
 310                                         info.block_size) - bg_desc_blocks;
 311
 312         if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
 313                 bg_desc_reserve_blocks = info.block_size / sizeof(u32);
 314
 315         return bg_desc_reserve_blocks;
 316 }
 317
 318 /* return a newly-malloc'd string that is a copy of str.  The new string
 319    is guaranteed to have a trailing slash.  If absolute is true, the new string
 320    is also guaranteed to have a leading slash.
 321 */
 322 static char *canonicalize_slashes(const char *str, bool absolute)
 323 {
 324         char *ret;
 325         int len = strlen(str);
 326         int newlen = len;
 327         char *ptr;
 328
 329         if (len == 0) {
 330                 if (absolute)
 331                         return strdup("/");
 332                 else
 333                         return strdup("");
 334         }
 335
 336         if (str[0] != '/' && absolute) {
 337                 newlen++;
 338         }
 339         if (str[len - 1] != '/') {
 340                 newlen++;
 341         }
 342         ret = malloc(newlen + 1);
 343         if (!ret) {
 344                 critical_error("malloc");
 345         }
 346
 347         ptr = ret;
 348         if (str[0] != '/' && absolute) {
 349                 *ptr++ = '/';
 350         }
 351
 352         strcpy(ptr, str);
 353         ptr += len;
 354
 355         if (str[len - 1] != '/') {
 356                 *ptr++ = '/';
 357         }
 358
 359         if (ptr != ret + newlen) {
 360                 critical_error("assertion failed\n");
 361         }
 362
 363         *ptr = '\0';
 364
 365         return ret;
 366 }
 367
 368 static char *canonicalize_abs_slashes(const char *str)
 369 {
 370         return canonicalize_slashes(str, true);
 371 }
 372
 373 static char *canonicalize_rel_slashes(const char *str)
 374 {
 375         return canonicalize_slashes(str, false);
 376 }
 377
 378 int make_ext4fs_internal(int fd, const char *_directory,
 379                                                  fs_config_func_t fs_config_func, int gzip,
 380                                                  int sparse, int crc, int wipe,
 381                                                  int verbose, time_t fixed_time,
 382                                                  FILE* block_list_file)
 383 {
 384         u32 root_inode_num;
 385         u16 root_mode;
 386         char *directory = NULL;
 387
 388         if (setjmp(setjmp_env))
 389                 return EXIT_FAILURE; /* Handle a call to longjmp() */
 390
 391         if (_directory)
 392                 directory = canonicalize_rel_slashes(_directory);
 393
 394         if (info.len <= 0)
 395                 info.len = get_file_size(fd);
 396
 397         if (info.len <= 0) {
 398                 fprintf(stderr, "Need size of filesystem\n");
 399                 return EXIT_FAILURE;
 400         }
 401
 402         if (info.block_size <= 0)
 403                 info.block_size = compute_block_size();
 404
 405         /* Round down the filesystem length to be a multiple of the block size */
 406         info.len &= ~((u64)info.block_size - 1);
 407
 408         if (info.journal_blocks == 0)
 409                 info.journal_blocks = compute_journal_blocks();
 410
 411         if (info.no_journal == 0)
 412                 info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL;
 413         else
 414                 info.journal_blocks = 0;
 415
 416         if (info.blocks_per_group <= 0)
 417                 info.blocks_per_group = compute_blocks_per_group();
 418
 419         if (info.inodes <= 0)
 420                 info.inodes = compute_inodes();
 421
 422         if (info.inode_size <= 0)
 423                 info.inode_size = 256;
 424
 425         if (info.label == NULL)
 426                 info.label = "";
 427
 428         info.inodes_per_group = compute_inodes_per_group();
 429
 430         info.feat_compat |=
 431                         EXT4_FEATURE_COMPAT_RESIZE_INODE |
 432                         EXT4_FEATURE_COMPAT_EXT_ATTR;
 433
 434         info.feat_ro_compat |=
 435                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER |
 436                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE |
 437                         EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 438
 439         info.feat_incompat |=
 440                         EXT4_FEATURE_INCOMPAT_EXTENTS |
 441                         EXT4_FEATURE_INCOMPAT_FILETYPE;
 442
 443
 444         info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks();
 445
 446         printf("Creating filesystem with parameters:\n");
 447         printf("    Size: %"PRIu64"\n", info.len);
 448         printf("    Block size: %d\n", info.block_size);
 449         printf("    Blocks per group: %d\n", info.blocks_per_group);
 450         printf("    Inodes per group: %d\n", info.inodes_per_group);
 451         printf("    Inode size: %d\n", info.inode_size);
 452         printf("    Journal blocks: %d\n", info.journal_blocks);
 453         printf("    Label: %s\n", info.label);
 454
 455         ext4_create_fs_aux_info();
 456
 457         printf("    Blocks: %"PRIu64"\n", aux_info.len_blocks);
 458         printf("    Block groups: %d\n", aux_info.groups);
 459         printf("    Reserved blocks: %"PRIu64"\n",  (aux_info.len_blocks / 100) * info.reserve_pcnt);
 460         printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 461
 462         ext4_sparse_file = sparse_file_new(info.block_size, info.len);
 463
 464         block_allocator_init();
 465
 466         ext4_fill_in_sb();
 467
 468         if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
 469                 error("failed to reserve first 10 inodes");
 470
 471         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 472                 ext4_create_journal_inode();
 473
 474         if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
 475                 ext4_create_resize_inode();
 476
 477         if (directory)
 478                 root_inode_num = build_directory_structure(directory, "", 0,
 479                         fs_config_func, verbose, fixed_time);
 480         else
 481                 root_inode_num = build_default_directory_structure(fixed_time);
 482
 483         root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 484         inode_set_permissions(root_inode_num, root_mode, 0, 0,
 485                 (fixed_time != 1) ? fixed_time : 0);
 486
 487         ext4_update_free();
 488
 489         ext4_queue_sb();
 490
 491         if (block_list_file) {
 492                 size_t dirlen = strlen(directory);
 493                 struct block_allocation* p = get_saved_allocation_chain();
 494                 while (p) {
 495                         if (strncmp(p->filename, directory, dirlen) == 0) {
 496                                 fprintf(block_list_file, "%s", p->filename + dirlen);
 497                         } else {
 498                                 fprintf(block_list_file, "%s", p->filename);
 499                         }
 500                         print_blocks(block_list_file, p);
 501                         struct block_allocation* pn = p->next;
 502                         free_alloc(p);
 503                         p = pn;
 504                 }
 505         }
 506
 507         printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
 508                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 509                         aux_info.sb->s_inodes_count,
 510                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 511                         aux_info.sb->s_blocks_count_lo);
 512
 513         if (wipe && WIPE_IS_SUPPORTED) {
 514                 wipe_block_device(fd, info.len);
 515         }
 516
 517         write_ext4_image(fd, gzip, sparse, crc);
 518
 519         sparse_file_destroy(ext4_sparse_file);
 520         ext4_sparse_file = NULL;
 521
 522         free(directory);
 523
 524         return 0;
 525 }