make_ext4fs.c revision 7907ac7c811670643c3606125657a39226507ea1
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#ifdef USE_MINGW 39 40#include <winsock2.h> 41 42/* These match the Linux definitions of these flags. 43 L_xx is defined to avoid conflicting with the win32 versions. 44*/ 45#define L_S_IRUSR 00400 46#define L_S_IWUSR 00200 47#define L_S_IXUSR 00100 48#define S_IRWXU (L_S_IRUSR | L_S_IWUSR | L_S_IXUSR) 49#define S_IRGRP 00040 50#define S_IWGRP 00020 51#define S_IXGRP 00010 52#define S_IRWXG (S_IRGRP | S_IWGRP | S_IXGRP) 53#define S_IROTH 00004 54#define S_IWOTH 00002 55#define S_IXOTH 00001 56#define S_IRWXO (S_IROTH | S_IWOTH | S_IXOTH) 57#define S_ISUID 0004000 58#define S_ISGID 0002000 59#define S_ISVTX 0001000 60 61#else 62 63#include <selinux/selinux.h> 64#include <selinux/label.h> 65#include <selinux/android.h> 66 67#define O_BINARY 0 68 69#endif 70 71/* TODO: Not implemented: 72 Allocating blocks in the same block group as the file inode 73 Hash or binary tree directories 74 Special files: sockets, devices, fifos 75 */ 76 77static int filter_dot(const struct dirent *d) 78{ 79 return (strcmp(d->d_name, "..") && strcmp(d->d_name, ".")); 80} 81 82static u32 build_default_directory_structure(const char *dir_path, 83 struct selabel_handle *sehnd) 84{ 85 u32 inode; 86 u32 root_inode; 87 struct dentry dentries = { 88 .filename = "lost+found", 89 .file_type = EXT4_FT_DIR, 90 .mode = S_IRWXU, 91 .uid = 0, 92 .gid = 0, 93 .mtime = 0, 94 }; 95 root_inode = make_directory(0, 1, &dentries, 1); 96 inode = make_directory(root_inode, 0, NULL, 0); 97 *dentries.inode = inode; 98 inode_set_permissions(inode, dentries.mode, 99 dentries.uid, dentries.gid, dentries.mtime); 100 101#ifndef USE_MINGW 102 if (sehnd) { 103 char *path = NULL; 104 char *secontext = NULL; 105 106 asprintf(&path, "%slost+found", dir_path); 107 if (selabel_lookup(sehnd, &secontext, path, S_IFDIR) < 0) { 108 error("cannot lookup security context for %s", path); 109 } else { 110 inode_set_selinux(inode, secontext); 111 freecon(secontext); 112 } 113 free(path); 114 } 115#endif 116 117 return root_inode; 118} 119 120#ifndef USE_MINGW 121/* Read a local directory and create the same tree in the generated filesystem. 122 Calls itself recursively with each directory in the given directory. 123 full_path is an absolute or relative path, with a trailing slash, to the 124 directory on disk that should be copied, or NULL if this is a directory 125 that does not exist on disk (e.g. lost+found). 126 dir_path is an absolute path, with trailing slash, to the same directory 127 if the image were mounted at the specified mount point */ 128static u32 build_directory_structure(const char *full_path, const char *dir_path, 129 u32 dir_inode, fs_config_func_t fs_config_func, 130 struct selabel_handle *sehnd, int verbose) 131{ 132 int entries = 0; 133 struct dentry *dentries; 134 struct dirent **namelist = NULL; 135 struct stat stat; 136 int ret; 137 int i; 138 u32 inode; 139 u32 entry_inode; 140 u32 dirs = 0; 141 bool needs_lost_and_found = false; 142 143 if (full_path) { 144 entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort); 145 if (entries < 0) { 146 error_errno("scandir"); 147 return EXT4_ALLOCATE_FAILED; 148 } 149 } 150 151 if (dir_inode == 0) { 152 /* root directory, check if lost+found already exists */ 153 for (i = 0; i < entries; i++) 154 if (strcmp(namelist[i]->d_name, "lost+found") == 0) 155 break; 156 if (i == entries) 157 needs_lost_and_found = true; 158 } 159 160 dentries = calloc(entries, sizeof(struct dentry)); 161 if (dentries == NULL) 162 critical_error_errno("malloc"); 163 164 for (i = 0; i < entries; i++) { 165 dentries[i].filename = strdup(namelist[i]->d_name); 166 if (dentries[i].filename == NULL) 167 critical_error_errno("strdup"); 168 169 asprintf(&dentries[i].path, "%s%s", dir_path, namelist[i]->d_name); 170 asprintf(&dentries[i].full_path, "%s%s", full_path, namelist[i]->d_name); 171 172 free(namelist[i]); 173 174 ret = lstat(dentries[i].full_path, &stat); 175 if (ret < 0) { 176 error_errno("lstat"); 177 i--; 178 entries--; 179 continue; 180 } 181 182 dentries[i].size = stat.st_size; 183 dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO); 184 dentries[i].mtime = stat.st_mtime; 185 uint64_t capabilities; 186 if (fs_config_func != NULL) { 187#ifdef ANDROID 188 unsigned int mode = 0; 189 unsigned int uid = 0; 190 unsigned int gid = 0; 191 int dir = S_ISDIR(stat.st_mode); 192 fs_config_func(dentries[i].path, dir, &uid, &gid, &mode, &capabilities); 193 dentries[i].mode = mode; 194 dentries[i].uid = uid; 195 dentries[i].gid = gid; 196 dentries[i].capabilities = capabilities; 197#else 198 error("can't set android permissions - built without android support"); 199#endif 200 } 201#ifndef USE_MINGW 202 if (sehnd) { 203 if (selabel_lookup(sehnd, &dentries[i].secon, dentries[i].path, stat.st_mode) < 0) { 204 error("cannot lookup security context for %s", dentries[i].path); 205 } 206 207 if (dentries[i].secon && verbose) 208 printf("Labeling %s as %s\n", dentries[i].path, dentries[i].secon); 209 } 210#endif 211 212 if (S_ISREG(stat.st_mode)) { 213 dentries[i].file_type = EXT4_FT_REG_FILE; 214 } else if (S_ISDIR(stat.st_mode)) { 215 dentries[i].file_type = EXT4_FT_DIR; 216 dirs++; 217 } else if (S_ISCHR(stat.st_mode)) { 218 dentries[i].file_type = EXT4_FT_CHRDEV; 219 } else if (S_ISBLK(stat.st_mode)) { 220 dentries[i].file_type = EXT4_FT_BLKDEV; 221 } else if (S_ISFIFO(stat.st_mode)) { 222 dentries[i].file_type = EXT4_FT_FIFO; 223 } else if (S_ISSOCK(stat.st_mode)) { 224 dentries[i].file_type = EXT4_FT_SOCK; 225 } else if (S_ISLNK(stat.st_mode)) { 226 dentries[i].file_type = EXT4_FT_SYMLINK; 227 dentries[i].link = calloc(info.block_size, 1); 228 readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1); 229 } else { 230 error("unknown file type on %s", dentries[i].path); 231 i--; 232 entries--; 233 } 234 } 235 free(namelist); 236 237 if (needs_lost_and_found) { 238 /* insert a lost+found directory at the beginning of the dentries */ 239 struct dentry *tmp = calloc(entries + 1, sizeof(struct dentry)); 240 memset(tmp, 0, sizeof(struct dentry)); 241 memcpy(tmp + 1, dentries, entries * sizeof(struct dentry)); 242 dentries = tmp; 243 244 dentries[0].filename = strdup("lost+found"); 245 asprintf(&dentries[0].path, "%slost+found", dir_path); 246 dentries[0].full_path = NULL; 247 dentries[0].size = 0; 248 dentries[0].mode = S_IRWXU; 249 dentries[0].file_type = EXT4_FT_DIR; 250 dentries[0].uid = 0; 251 dentries[0].gid = 0; 252 if (sehnd) { 253 if (selabel_lookup(sehnd, &dentries[0].secon, dentries[0].path, dentries[0].mode) < 0) 254 error("cannot lookup security context for %s", dentries[0].path); 255 } 256 entries++; 257 dirs++; 258 } 259 260 inode = make_directory(dir_inode, entries, dentries, dirs); 261 262 for (i = 0; i < entries; i++) { 263 if (dentries[i].file_type == EXT4_FT_REG_FILE) { 264 entry_inode = make_file(dentries[i].full_path, dentries[i].size); 265 } else if (dentries[i].file_type == EXT4_FT_DIR) { 266 char *subdir_full_path = NULL; 267 char *subdir_dir_path; 268 if (dentries[i].full_path) { 269 ret = asprintf(&subdir_full_path, "%s/", dentries[i].full_path); 270 if (ret < 0) 271 critical_error_errno("asprintf"); 272 } 273 ret = asprintf(&subdir_dir_path, "%s/", dentries[i].path); 274 if (ret < 0) 275 critical_error_errno("asprintf"); 276 entry_inode = build_directory_structure(subdir_full_path, 277 subdir_dir_path, inode, fs_config_func, sehnd, verbose); 278 free(subdir_full_path); 279 free(subdir_dir_path); 280 } else if (dentries[i].file_type == EXT4_FT_SYMLINK) { 281 entry_inode = make_link(dentries[i].link); 282 } else { 283 error("unknown file type on %s", dentries[i].path); 284 entry_inode = 0; 285 } 286 *dentries[i].inode = entry_inode; 287 288 ret = inode_set_permissions(entry_inode, dentries[i].mode, 289 dentries[i].uid, dentries[i].gid, 290 dentries[i].mtime); 291 if (ret) 292 error("failed to set permissions on %s\n", dentries[i].path); 293 294 /* 295 * It's important to call inode_set_selinux() before 296 * inode_set_capabilities(). Extended attributes need to 297 * be stored sorted order, and we guarantee this by making 298 * the calls in the proper order. 299 * Please see xattr_assert_sane() in contents.c 300 */ 301 ret = inode_set_selinux(entry_inode, dentries[i].secon); 302 if (ret) 303 error("failed to set SELinux context on %s\n", dentries[i].path); 304 ret = inode_set_capabilities(entry_inode, dentries[i].capabilities); 305 if (ret) 306 error("failed to set capability on %s\n", dentries[i].path); 307 308 free(dentries[i].path); 309 free(dentries[i].full_path); 310 free(dentries[i].link); 311 free((void *)dentries[i].filename); 312 free(dentries[i].secon); 313 } 314 315 free(dentries); 316 return inode; 317} 318#endif 319 320static u32 compute_block_size() 321{ 322 return 4096; 323} 324 325static u32 compute_journal_blocks() 326{ 327 u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64; 328 if (journal_blocks < 1024) 329 journal_blocks = 1024; 330 if (journal_blocks > 32768) 331 journal_blocks = 32768; 332 return journal_blocks; 333} 334 335static u32 compute_blocks_per_group() 336{ 337 return info.block_size * 8; 338} 339 340static u32 compute_inodes() 341{ 342 return DIV_ROUND_UP(info.len, info.block_size) / 4; 343} 344 345static u32 compute_inodes_per_group() 346{ 347 u32 blocks = DIV_ROUND_UP(info.len, info.block_size); 348 u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group); 349 u32 inodes = DIV_ROUND_UP(info.inodes, block_groups); 350 inodes = ALIGN(inodes, (info.block_size / info.inode_size)); 351 352 /* After properly rounding up the number of inodes/group, 353 * make sure to update the total inodes field in the info struct. 354 */ 355 info.inodes = inodes * block_groups; 356 357 return inodes; 358} 359 360static u32 compute_bg_desc_reserve_blocks() 361{ 362 u32 blocks = DIV_ROUND_UP(info.len, info.block_size); 363 u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group); 364 u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc), 365 info.block_size); 366 367 u32 bg_desc_reserve_blocks = 368 DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc), 369 info.block_size) - bg_desc_blocks; 370 371 if (bg_desc_reserve_blocks > info.block_size / sizeof(u32)) 372 bg_desc_reserve_blocks = info.block_size / sizeof(u32); 373 374 return bg_desc_reserve_blocks; 375} 376 377void reset_ext4fs_info() { 378 // Reset all the global data structures used by make_ext4fs so it 379 // can be called again. 380 memset(&info, 0, sizeof(info)); 381 memset(&aux_info, 0, sizeof(aux_info)); 382 383 if (ext4_sparse_file) { 384 sparse_file_destroy(ext4_sparse_file); 385 ext4_sparse_file = NULL; 386 } 387} 388 389int make_ext4fs_sparse_fd(int fd, long long len, 390 const char *mountpoint, struct selabel_handle *sehnd) 391{ 392 reset_ext4fs_info(); 393 info.len = len; 394 395 return make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 1, 0, 0, sehnd, 0); 396} 397 398int make_ext4fs(const char *filename, long long len, 399 const char *mountpoint, struct selabel_handle *sehnd) 400{ 401 int fd; 402 int status; 403 404 reset_ext4fs_info(); 405 info.len = len; 406 407 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); 408 if (fd < 0) { 409 error_errno("open"); 410 return EXIT_FAILURE; 411 } 412 413 status = make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 0, 0, 1, sehnd, 0); 414 close(fd); 415 416 return status; 417} 418 419/* return a newly-malloc'd string that is a copy of str. The new string 420 is guaranteed to have a trailing slash. If absolute is true, the new string 421 is also guaranteed to have a leading slash. 422*/ 423static char *canonicalize_slashes(const char *str, bool absolute) 424{ 425 char *ret; 426 int len = strlen(str); 427 int newlen = len; 428 char *ptr; 429 430 if (len == 0 && absolute) { 431 return strdup("/"); 432 } 433 434 if (str[0] != '/' && absolute) { 435 newlen++; 436 } 437 if (str[len - 1] != '/') { 438 newlen++; 439 } 440 ret = malloc(newlen + 1); 441 if (!ret) { 442 critical_error("malloc"); 443 } 444 445 ptr = ret; 446 if (str[0] != '/' && absolute) { 447 *ptr++ = '/'; 448 } 449 450 strcpy(ptr, str); 451 ptr += len; 452 453 if (str[len - 1] != '/') { 454 *ptr++ = '/'; 455 } 456 457 if (ptr != ret + newlen) { 458 critical_error("assertion failed\n"); 459 } 460 461 *ptr = '\0'; 462 463 return ret; 464} 465 466static char *canonicalize_abs_slashes(const char *str) 467{ 468 return canonicalize_slashes(str, true); 469} 470 471static char *canonicalize_rel_slashes(const char *str) 472{ 473 return canonicalize_slashes(str, false); 474} 475 476int make_ext4fs_internal(int fd, const char *_directory, 477 const char *_mountpoint, fs_config_func_t fs_config_func, int gzip, 478 int sparse, int crc, int wipe, 479 struct selabel_handle *sehnd, int verbose) 480{ 481 u32 root_inode_num; 482 u16 root_mode; 483 char *mountpoint; 484 char *directory = NULL; 485 486 if (setjmp(setjmp_env)) 487 return EXIT_FAILURE; /* Handle a call to longjmp() */ 488 489 if (_mountpoint == NULL) { 490 mountpoint = strdup(""); 491 } else { 492 mountpoint = canonicalize_abs_slashes(_mountpoint); 493 } 494 495 if (_directory) { 496 directory = canonicalize_rel_slashes(_directory); 497 } 498 499 if (info.len <= 0) 500 info.len = get_file_size(fd); 501 502 if (info.len <= 0) { 503 fprintf(stderr, "Need size of filesystem\n"); 504 return EXIT_FAILURE; 505 } 506 507 if (info.block_size <= 0) 508 info.block_size = compute_block_size(); 509 510 /* Round down the filesystem length to be a multiple of the block size */ 511 info.len &= ~((u64)info.block_size - 1); 512 513 if (info.journal_blocks == 0) 514 info.journal_blocks = compute_journal_blocks(); 515 516 if (info.no_journal == 0) 517 info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL; 518 else 519 info.journal_blocks = 0; 520 521 if (info.blocks_per_group <= 0) 522 info.blocks_per_group = compute_blocks_per_group(); 523 524 if (info.inodes <= 0) 525 info.inodes = compute_inodes(); 526 527 if (info.inode_size <= 0) 528 info.inode_size = 256; 529 530 if (info.label == NULL) 531 info.label = ""; 532 533 info.inodes_per_group = compute_inodes_per_group(); 534 535 info.feat_compat |= 536 EXT4_FEATURE_COMPAT_RESIZE_INODE | 537 EXT4_FEATURE_COMPAT_EXT_ATTR; 538 539 info.feat_ro_compat |= 540 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER | 541 EXT4_FEATURE_RO_COMPAT_LARGE_FILE | 542 EXT4_FEATURE_RO_COMPAT_GDT_CSUM; 543 544 info.feat_incompat |= 545 EXT4_FEATURE_INCOMPAT_EXTENTS | 546 EXT4_FEATURE_INCOMPAT_FILETYPE; 547 548 549 info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks(); 550 551 printf("Creating filesystem with parameters:\n"); 552 printf(" Size: %"PRIu64"\n", info.len); 553 printf(" Block size: %d\n", info.block_size); 554 printf(" Blocks per group: %d\n", info.blocks_per_group); 555 printf(" Inodes per group: %d\n", info.inodes_per_group); 556 printf(" Inode size: %d\n", info.inode_size); 557 printf(" Journal blocks: %d\n", info.journal_blocks); 558 printf(" Label: %s\n", info.label); 559 560 ext4_create_fs_aux_info(); 561 562 printf(" Blocks: %"PRIu64"\n", aux_info.len_blocks); 563 printf(" Block groups: %d\n", aux_info.groups); 564 printf(" Reserved block group size: %d\n", info.bg_desc_reserve_blocks); 565 566 ext4_sparse_file = sparse_file_new(info.block_size, info.len); 567 568 block_allocator_init(); 569 570 ext4_fill_in_sb(); 571 572 if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED) 573 error("failed to reserve first 10 inodes"); 574 575 if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL) 576 ext4_create_journal_inode(); 577 578 if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE) 579 ext4_create_resize_inode(); 580 581#ifdef USE_MINGW 582 // Windows needs only 'create an empty fs image' functionality 583 assert(!directory); 584 root_inode_num = build_default_directory_structure(mountpoint, sehnd); 585#else 586 if (directory) 587 root_inode_num = build_directory_structure(directory, mountpoint, 0, 588 fs_config_func, sehnd, verbose); 589 else 590 root_inode_num = build_default_directory_structure(mountpoint, sehnd); 591#endif 592 593 root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH; 594 inode_set_permissions(root_inode_num, root_mode, 0, 0, 0); 595 596#ifndef USE_MINGW 597 if (sehnd) { 598 char *secontext = NULL; 599 600 if (selabel_lookup(sehnd, &secontext, mountpoint, S_IFDIR) < 0) { 601 error("cannot lookup security context for %s", mountpoint); 602 } 603 if (secontext) { 604 if (verbose) { 605 printf("Labeling %s as %s\n", mountpoint, secontext); 606 } 607 inode_set_selinux(root_inode_num, secontext); 608 } 609 freecon(secontext); 610 } 611#endif 612 613 ext4_update_free(); 614 615 ext4_queue_sb(); 616 617 printf("Created filesystem with %d/%d inodes and %d/%d blocks\n", 618 aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count, 619 aux_info.sb->s_inodes_count, 620 aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo, 621 aux_info.sb->s_blocks_count_lo); 622 623 if (wipe) 624 wipe_block_device(fd, info.len); 625 626 write_ext4_image(fd, gzip, sparse, crc); 627 628 sparse_file_destroy(ext4_sparse_file); 629 ext4_sparse_file = NULL; 630 631 free(mountpoint); 632 free(directory); 633 634 return 0; 635} 636