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
  37 /* TODO: Not implemented:
  38    Allocating blocks in the same block group as the file inode
  39    Hash or binary tree directories
  40  */
  41
  42 static int filter_dot(const struct dirent *d)
  43 {
  44         return (strcmp(d->d_name, "..") && strcmp(d->d_name, "."));
  45 }
  46
  47 static u32 build_default_directory_structure(const char *dir_path)
  48 {
  49         u32 inode;
  50         u32 root_inode;
  51         struct dentry dentries = {
  52                         .filename = "lost+found",
  53                         .file_type = EXT4_FT_DIR,
  54                         .mode = S_IRWXU,
  55                         .uid = 0,
  56                         .gid = 0,
  57                         .mtime = 0,
  58         };
  59         root_inode = make_directory(0, 1, &dentries, 1);
  60         inode = make_directory(root_inode, 0, NULL, 0);
  61         *dentries.inode = inode;
  62         inode_set_permissions(inode, dentries.mode,
  63                 dentries.uid, dentries.gid, dentries.mtime);
  64
  65         return root_inode;
  66 }
  67
  68 /* Read a local directory and create the same tree in the generated filesystem.
  69    Calls itself recursively with each directory in the given directory.
  70    full_path is an absolute or relative path, with a trailing slash, to the
  71    directory on disk that should be copied, or NULL if this is a directory
  72    that does not exist on disk (e.g. lost+found).
  73    dir_path is an absolute path, with trailing slash, to the same directory
  74    if the image were mounted at the specified mount point */
  75 static u32 build_directory_structure(const char *full_path, const char *dir_path,
  76                 u32 dir_inode, fs_config_func_t fs_config_func,
  77                 int verbose, time_t fixed_time)
  78 {
  79         int entries = 0;
  80         struct dentry *dentries;
  81         struct dirent **namelist = NULL;
  82         struct stat stat;
  83         int ret;
  84         int i;
  85         u32 inode;
  86         u32 entry_inode;
  87         u32 dirs = 0;
  88         bool needs_lost_and_found = false;
  89
  90         if (full_path) {
  91                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
  92                 if (entries < 0) {
  93 #ifdef __GLIBC__
  94                         /* The scandir function implemented in glibc has a bug that makes it
  95                            erroneously fail with ENOMEM under certain circumstances.
  96                            As a workaround we can retry the scandir call with the same arguments.
  97                            GLIBC BZ: https://sourceware.org/bugzilla/show_bug.cgi?id=17804 */
  98                         if (errno == ENOMEM)
  99                                 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
 100 #endif
 101                         if (entries < 0) {
 102                                 error_errno("scandir");
 103                                 return EXT4_ALLOCATE_FAILED;
 104                         }
 105                 }
 106         }
 107
 108         if (dir_inode == 0) {
 109                 /* root directory, check if lost+found already exists */
 110                 for (i = 0; i < entries; i++)
 111                         if (strcmp(namelist[i]->d_name, "lost+found") == 0)
 112                                 break;
 113                 if (i == entries)
 114                         needs_lost_and_found = true;
 115         }
 116
 117         dentries = calloc(entries, sizeof(struct dentry));
 118         if (dentries == NULL)
 119                 critical_error_errno("malloc");
 120
 121         for (i = 0; i < entries; i++) {
 122                 dentries[i].filename = strdup(namelist[i]->d_name);
 123                 if (dentries[i].filename == NULL)
 124                         critical_error_errno("strdup");
 125
 126                 asprintf(&dentries[i].path, "%s%s", dir_path, namelist[i]->d_name);
 127                 asprintf(&dentries[i].full_path, "%s%s", full_path, namelist[i]->d_name);
 128
 129                 free(namelist[i]);
 130
 131                 ret = lstat(dentries[i].full_path, &stat);
 132                 if (ret < 0) {
 133                         error_errno("lstat");
 134                         i--;
 135                         entries--;
 136                         continue;
 137                 }
 138
 139                 dentries[i].size = stat.st_size;
 140                 dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO);
 141                 if (fixed_time == -1) {
 142                         dentries[i].mtime = stat.st_mtime;
 143                 } else {
 144                         dentries[i].mtime = fixed_time;
 145                 }
 146                 uint64_t capabilities;
 147                 if (fs_config_func != NULL) {
 148                         unsigned int mode = 0;
 149                         unsigned int uid = 0;
 150                         unsigned int gid = 0;
 151                         int dir = S_ISDIR(stat.st_mode);
 152                         if (fs_config_func(dentries[i].path, dir, &uid, &gid, &mode, &capabilities)) {
 153                                 dentries[i].mode = mode;
 154                                 dentries[i].uid = uid;
 155                                 dentries[i].gid = gid;
 156                                 dentries[i].capabilities = capabilities;
 157                         }
 158                 }
 159
 160                 if (S_ISREG(stat.st_mode)) {
 161                         dentries[i].file_type = EXT4_FT_REG_FILE;
 162                 } else if (S_ISDIR(stat.st_mode)) {
 163                         dentries[i].file_type = EXT4_FT_DIR;
 164                         dirs++;
 165                 } else if (S_ISCHR(stat.st_mode)) {
 166                         dentries[i].file_type = EXT4_FT_CHRDEV;
 167                 } else if (S_ISBLK(stat.st_mode)) {
 168                         dentries[i].file_type = EXT4_FT_BLKDEV;
 169                 } else if (S_ISFIFO(stat.st_mode)) {
 170                         dentries[i].file_type = EXT4_FT_FIFO;
 171                 } else if (S_ISSOCK(stat.st_mode)) {
 172                         dentries[i].file_type = EXT4_FT_SOCK;
 173                 } else if (S_ISLNK(stat.st_mode)) {
 174                         dentries[i].file_type = EXT4_FT_SYMLINK;
 175                         dentries[i].link = calloc(info.block_size, 1);
 176                         readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
 177                 } else {
 178                         error("unknown file type on %s", dentries[i].path);
 179                         i--;
 180                         entries--;
 181                 }
 182         }
 183         free(namelist);
 184
 185         if (needs_lost_and_found) {
 186                 /* insert a lost+found directory at the beginning of the dentries */
 187                 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry));
 188                 memset(tmp, 0, sizeof(struct dentry));
 189                 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry));
 190                 dentries = tmp;
 191
 192                 dentries[0].filename = strdup("lost+found");
 193                 asprintf(&dentries[0].path, "%slost+found", dir_path);
 194                 dentries[0].full_path = NULL;
 195                 dentries[0].size = 0;
 196                 dentries[0].mode = S_IRWXU;
 197                 dentries[0].file_type = EXT4_FT_DIR;
 198                 dentries[0].uid = 0;
 199                 dentries[0].gid = 0;
 200                 entries++;
 201                 dirs++;
 202         }
 203
 204         inode = make_directory(dir_inode, entries, dentries, dirs);
 205
 206         for (i = 0; i < entries; i++) {
 207                 if (dentries[i].file_type == EXT4_FT_REG_FILE) {
 208                         entry_inode = make_file(dentries[i].full_path, dentries[i].size);
 209                 } else if (dentries[i].file_type == EXT4_FT_DIR) {
 210                         char *subdir_full_path = NULL;
 211                         char *subdir_dir_path;
 212                         if (dentries[i].full_path) {
 213                                 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path);
 214                                 if (ret < 0)
 215                                         critical_error_errno("asprintf");
 216                         }
 217                         ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path);
 218                         if (ret < 0)
 219                                 critical_error_errno("asprintf");
 220                         entry_inode = build_directory_structure(subdir_full_path,
 221                                         subdir_dir_path, inode, fs_config_func, verbose, fixed_time);
 222                         free(subdir_full_path);
 223                         free(subdir_dir_path);
 224                 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
 225                         entry_inode = make_link(dentries[i].link);
 226                 } else if (dentries[i].file_type == EXT4_FT_CHRDEV ||
 227                            dentries[i].file_type == EXT4_FT_BLKDEV ||
 228                            dentries[i].file_type == EXT4_FT_SOCK ||
 229                            dentries[i].file_type == EXT4_FT_FIFO) {
 230                         entry_inode = make_special(dentries[i].full_path);
 231                 } else {
 232                         error("unknown file type on %s", dentries[i].path);
 233                         entry_inode = 0;
 234                 }
 235                 *dentries[i].inode = entry_inode;
 236
 237                 ret = inode_set_permissions(entry_inode, dentries[i].mode,
 238                         dentries[i].uid, dentries[i].gid,
 239                         dentries[i].mtime);
 240                 if (ret)
 241                         error("failed to set permissions on %s\n", dentries[i].path);
 242
 243                 ret = inode_set_capabilities(entry_inode, dentries[i].capabilities);
 244                 if (ret)
 245                         error("failed to set capability on %s\n", dentries[i].path);
 246
 247                 free(dentries[i].path);
 248                 free(dentries[i].full_path);
 249                 free(dentries[i].link);
 250                 free((void *)dentries[i].filename);
 251         }
 252
 253         free(dentries);
 254         return inode;
 255 }
 256
 257 static u32 compute_block_size()
 258 {
 259         return 4096;
 260 }
 261
 262 static u32 compute_journal_blocks()
 263 {
 264         u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
 265         if (journal_blocks < 1024)
 266                 journal_blocks = 1024;
 267         if (journal_blocks > 32768)
 268                 journal_blocks = 32768;
 269         return journal_blocks;
 270 }
 271
 272 static u32 compute_blocks_per_group()
 273 {
 274         return info.block_size * 8;
 275 }
 276
 277 static u32 compute_inodes()
 278 {
 279         return DIV_ROUND_UP(info.len, info.block_size) / 4;
 280 }
 281
 282 static u32 compute_inodes_per_group()
 283 {
 284         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 285         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 286         u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
 287         inodes = EXT4_ALIGN(inodes, (info.block_size / info.inode_size));
 288
 289         /* After properly rounding up the number of inodes/group,
 290          * make sure to update the total inodes field in the info struct.
 291          */
 292         info.inodes = inodes * block_groups;
 293
 294         return inodes;
 295 }
 296
 297 static u32 compute_bg_desc_reserve_blocks()
 298 {
 299         u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
 300         u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
 301         u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
 302                         info.block_size);
 303
 304         u32 bg_desc_reserve_blocks =
 305                         DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
 306                                         info.block_size) - bg_desc_blocks;
 307
 308         if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
 309                 bg_desc_reserve_blocks = info.block_size / sizeof(u32);
 310
 311         return bg_desc_reserve_blocks;
 312 }
 313
 314 /* return a newly-malloc'd string that is a copy of str.  The new string
 315    is guaranteed to have a trailing slash.  If absolute is true, the new string
 316    is also guaranteed to have a leading slash.
 317 */
 318 static char *canonicalize_slashes(const char *str, bool absolute)
 319 {
 320         char *ret;
 321         int len = strlen(str);
 322         int newlen = len;
 323         char *ptr;
 324
 325         if (len == 0) {
 326                 if (absolute)
 327                         return strdup("/");
 328                 else
 329                         return strdup("");
 330         }
 331
 332         if (str[0] != '/' && absolute) {
 333                 newlen++;
 334         }
 335         if (str[len - 1] != '/') {
 336                 newlen++;
 337         }
 338         ret = malloc(newlen + 1);
 339         if (!ret) {
 340                 critical_error("malloc");
 341         }
 342
 343         ptr = ret;
 344         if (str[0] != '/' && absolute) {
 345                 *ptr++ = '/';
 346         }
 347
 348         strcpy(ptr, str);
 349         ptr += len;
 350
 351         if (str[len - 1] != '/') {
 352                 *ptr++ = '/';
 353         }
 354
 355         if (ptr != ret + newlen) {
 356                 critical_error("assertion failed\n");
 357         }
 358
 359         *ptr = '\0';
 360
 361         return ret;
 362 }
 363
 364 static char *canonicalize_abs_slashes(const char *str)
 365 {
 366         return canonicalize_slashes(str, true);
 367 }
 368
 369 static char *canonicalize_rel_slashes(const char *str)
 370 {
 371         return canonicalize_slashes(str, false);
 372 }
 373
 374 int make_ext4fs_internal(int fd, const char *_directory,
 375                                                  fs_config_func_t fs_config_func, int gzip,
 376                                                  int sparse, int crc, int wipe,
 377                                                  int verbose, time_t fixed_time,
 378                                                  FILE* block_list_file)
 379 {
 380         u32 root_inode_num;
 381         u16 root_mode;
 382         char *directory = NULL;
 383
 384         if (setjmp(setjmp_env))
 385                 return EXIT_FAILURE; /* Handle a call to longjmp() */
 386
 387         if (_directory == NULL) {
 388                 fprintf(stderr, "Need a source directory\n");
 389                 return EXIT_FAILURE;
 390         }
 391
 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 block group size: %d\n", info.bg_desc_reserve_blocks);
 460
 461         ext4_sparse_file = sparse_file_new(info.block_size, info.len);
 462
 463         block_allocator_init();
 464
 465         ext4_fill_in_sb();
 466
 467         if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
 468                 error("failed to reserve first 10 inodes");
 469
 470         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 471                 ext4_create_journal_inode();
 472
 473         if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
 474                 ext4_create_resize_inode();
 475
 476         root_inode_num = build_directory_structure(directory, "", 0,
 477                 fs_config_func, verbose, fixed_time);
 478
 479         root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 480         inode_set_permissions(root_inode_num, root_mode, 0, 0, 0);
 481
 482         ext4_update_free();
 483
 484         ext4_queue_sb();
 485
 486         if (block_list_file) {
 487                 size_t dirlen = strlen(directory);
 488                 struct block_allocation* p = get_saved_allocation_chain();
 489                 while (p) {
 490                         if (strncmp(p->filename, directory, dirlen) == 0) {
 491                                 fprintf(block_list_file, "%s", p->filename + dirlen);
 492                         } else {
 493                                 fprintf(block_list_file, "%s", p->filename);
 494                         }
 495                         print_blocks(block_list_file, p);
 496                         struct block_allocation* pn = p->next;
 497                         free_alloc(p);
 498                         p = pn;
 499                 }
 500         }
 501
 502         printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
 503                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 504                         aux_info.sb->s_inodes_count,
 505                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 506                         aux_info.sb->s_blocks_count_lo);
 507
 508         if (wipe && WIPE_IS_SUPPORTED) {
 509                 wipe_block_device(fd, info.len);
 510         }
 511
 512         write_ext4_image(fd, gzip, sparse, crc);
 513
 514         sparse_file_destroy(ext4_sparse_file);
 515         ext4_sparse_file = NULL;
 516
 517         free(directory);
 518
 519         return 0;
 520 }