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