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