1/* mke2fs.c - Create an ext2 filesystem image. 2 * 3 * Copyright 2006, 2007 Rob Landley <rob@landley.net> 4 5// Still to go: "E:jJ:L:m:O:" 6USE_MKE2FS(NEWTOY(mke2fs, "<1>2g:Fnqm#N#i#b#", TOYFLAG_SBIN)) 7 8config MKE2FS 9 bool "mke2fs" 10 default n 11 help 12 usage: mke2fs [-Fnq] [-b ###] [-N|i ###] [-m ###] device 13 14 Create an ext2 filesystem on a block device or filesystem image. 15 16 -F Force to run on a mounted device 17 -n Don't write to device 18 -q Quiet (no output) 19 -b size Block size (1024, 2048, or 4096) 20 -N inodes Allocate this many inodes 21 -i bytes Allocate one inode for every XXX bytes of device 22 -m percent Reserve this percent of filesystem space for root user 23 24config MKE2FS_JOURNAL 25 bool "Journaling support (ext3)" 26 default n 27 depends on MKE2FS 28 help 29 usage: mke2fs [-j] [-J size=###,device=XXX] 30 31 -j Create journal (ext3) 32 -J Journal options 33 size: Number of blocks (1024-102400) 34 device: Specify an external journal 35 36config MKE2FS_GEN 37 bool "Generate (gene2fs)" 38 default n 39 depends on MKE2FS 40 help 41 usage: gene2fs [options] device filename 42 43 The [options] are the same as mke2fs. 44 45config MKE2FS_LABEL 46 bool "Label support" 47 default n 48 depends on MKE2FS 49 help 50 usage: mke2fs [-L label] [-M path] [-o string] 51 52 -L Volume label 53 -M Path to mount point 54 -o Created by 55 56config MKE2FS_EXTENDED 57 bool "Extended options" 58 default n 59 depends on MKE2FS 60 help 61 usage: mke2fs [-E stride=###] [-O option[,option]] 62 63 -E stride= Set RAID stripe size (in blocks) 64 -O [opts] Specify fewer ext2 option flags (for old kernels) 65 All of these are on by default (as appropriate) 66 none Clear default options (all but journaling) 67 dir_index Use htree indexes for large directories 68 filetype Store file type info in directory entry 69 has_journal Set by -j 70 journal_dev Set by -J device=XXX 71 sparse_super Don't allocate huge numbers of redundant superblocks 72*/ 73 74#define FOR_mke2fs 75#include "toys.h" 76 77GLOBALS( 78 // Command line arguments. 79 long blocksize; 80 long bytes_per_inode; 81 long inodes; // Total inodes in filesystem. 82 long reserved_percent; // Integer precent of space to reserve for root. 83 char *gendir; // Where to read dirtree from. 84 85 // Internal data. 86 struct dirtree *dt; // Tree of files to copy into the new filesystem. 87 unsigned treeblocks; // Blocks used by dt 88 unsigned treeinodes; // Inodes used by dt 89 90 unsigned blocks; // Total blocks in the filesystem. 91 unsigned freeblocks; // Free blocks in the filesystem. 92 unsigned inodespg; // Inodes per group 93 unsigned groups; // Total number of block groups. 94 unsigned blockbits; // Bits per block. (Also blocks per group.) 95 96 // For gene2fs 97 unsigned nextblock; // Next data block to allocate 98 unsigned nextgroup; // Next group we'll be allocating from 99 int fsfd; // File descriptor of filesystem (to output to). 100 101 struct ext2_superblock sb; 102) 103 104#define INODES_RESERVED 10 105 106static uint32_t div_round_up(uint32_t a, uint32_t b) 107{ 108 uint32_t c = a/b; 109 110 if (a%b) c++; 111 return c; 112} 113 114// Calculate data blocks plus index blocks needed to hold a file. 115 116static uint32_t file_blocks_used(uint64_t size, uint32_t *blocklist) 117{ 118 uint32_t dblocks = (uint32_t)((size+(TT.blocksize-1))/TT.blocksize); 119 uint32_t idx=TT.blocksize/4, iblocks=0, diblocks=0, tiblocks=0; 120 121 // Fill out index blocks in inode. 122 123 if (blocklist) { 124 int i; 125 126 // Direct index blocks 127 for (i=0; i<13 && i<dblocks; i++) blocklist[i] = i; 128 // Singly indirect index blocks 129 if (dblocks > 13+idx) blocklist[13] = 13+idx; 130 // Doubly indirect index blocks 131 idx = 13 + idx + (idx*idx); 132 if (dblocks > idx) blocklist[14] = idx; 133 134 return 0; 135 } 136 137 // Account for direct, singly, doubly, and triply indirect index blocks 138 139 if (dblocks > 12) { 140 iblocks = ((dblocks-13)/idx)+1; 141 if (iblocks > 1) { 142 diblocks = ((iblocks-2)/idx)+1; 143 if (diblocks > 1) 144 tiblocks = ((diblocks-2)/idx)+1; 145 } 146 } 147 148 return dblocks + iblocks + diblocks + tiblocks; 149} 150 151// Use the parent pointer to iterate through the tree non-recursively. 152static struct dirtree *treenext(struct dirtree *this) 153{ 154 while (this && !this->next) this = this->parent; 155 if (this) this = this->next; 156 157 return this; 158} 159 160// Recursively calculate the number of blocks used by each inode in the tree. 161// Returns blocks used by this directory, assigns bytes used to *size. 162// Writes total block count to TT.treeblocks and inode count to TT.treeinodes. 163 164static long check_treesize(struct dirtree *that, off_t *size) 165{ 166 long blocks; 167 168 while (that) { 169 *size += sizeof(struct ext2_dentry) + strlen(that->name); 170 171 if (that->child) 172 that->st.st_blocks = check_treesize(that->child, &that->st.st_size); 173 else if (S_ISREG(that->st.st_mode)) { 174 that->st.st_blocks = file_blocks_used(that->st.st_size, 0); 175 TT.treeblocks += that->st.st_blocks; 176 } 177 that = that->next; 178 } 179 TT.treeblocks += blocks = file_blocks_used(*size, 0); 180 TT.treeinodes++; 181 182 return blocks; 183} 184 185// Calculate inode numbers and link counts. 186// 187// To do this right I need to copy the tree and sort it, but here's a really 188// ugly n^2 way of dealing with the problem that doesn't scale well to large 189// numbers of files (> 100,000) but can be done in very little code. 190// This rewrites inode numbers to their final values, allocating depth first. 191 192static void check_treelinks(struct dirtree *tree) 193{ 194 struct dirtree *current=tree, *that; 195 long inode = INODES_RESERVED; 196 197 while (current) { 198 ++inode; 199 // Since we can't hardlink to directories, we know their link count. 200 if (S_ISDIR(current->st.st_mode)) current->st.st_nlink = 2; 201 else { 202 dev_t new = current->st.st_dev; 203 204 if (!new) continue; 205 206 // Look for other copies of current node 207 current->st.st_nlink = 0; 208 for (that = tree; that; that = treenext(that)) { 209 if (current->st.st_ino == that->st.st_ino && 210 current->st.st_dev == that->st.st_dev) 211 { 212 current->st.st_nlink++; 213 current->st.st_ino = inode; 214 } 215 } 216 } 217 current->st.st_ino = inode; 218 current = treenext(current); 219 } 220} 221 222// Calculate inodes per group from total inodes. 223static uint32_t get_inodespg(uint32_t inodes) 224{ 225 uint32_t temp; 226 227 // Round up to fill complete inode blocks. 228 temp = (inodes + TT.groups - 1) / TT.groups; 229 inodes = TT.blocksize/sizeof(struct ext2_inode); 230 return ((temp + inodes - 1)/inodes)*inodes; 231} 232 233// Fill out superblock and TT structures. 234 235static void init_superblock(struct ext2_superblock *sb) 236{ 237 uint32_t temp; 238 239 // Set log_block_size and log_frag_size. 240 241 for (temp = 0; temp < 4; temp++) if (TT.blocksize == 1024<<temp) break; 242 if (temp==4) error_exit("bad blocksize"); 243 sb->log_block_size = sb->log_frag_size = SWAP_LE32(temp); 244 245 // Fill out blocks_count, r_blocks_count, first_data_block 246 247 sb->blocks_count = SWAP_LE32(TT.blocks); 248 sb->free_blocks_count = SWAP_LE32(TT.freeblocks); 249 temp = (TT.blocks * (uint64_t)TT.reserved_percent) / 100; 250 sb->r_blocks_count = SWAP_LE32(temp); 251 252 sb->first_data_block = SWAP_LE32(TT.blocksize == 1024 ? 1 : 0); 253 254 // Set blocks_per_group and frags_per_group, which is the size of an 255 // allocation bitmap that fits in one block (I.E. how many bits per block)? 256 257 sb->blocks_per_group = sb->frags_per_group = SWAP_LE32(TT.blockbits); 258 259 // Set inodes_per_group and total inodes_count 260 sb->inodes_per_group = SWAP_LE32(TT.inodespg); 261 sb->inodes_count = SWAP_LE32(TT.inodespg * TT.groups); 262 263 // Determine free inodes. 264 temp = TT.inodespg*TT.groups - INODES_RESERVED; 265 if (temp < TT.treeinodes) error_exit("Not enough inodes.\n"); 266 sb->free_inodes_count = SWAP_LE32(temp - TT.treeinodes); 267 268 // Fill out the rest of the superblock. 269 sb->max_mnt_count=0xFFFF; 270 sb->wtime = sb->lastcheck = sb->mkfs_time = SWAP_LE32(time(NULL)); 271 sb->magic = SWAP_LE32(0xEF53); 272 sb->state = sb->errors = SWAP_LE16(1); 273 274 sb->rev_level = SWAP_LE32(1); 275 sb->first_ino = SWAP_LE32(INODES_RESERVED+1); 276 sb->inode_size = SWAP_LE16(sizeof(struct ext2_inode)); 277 sb->feature_incompat = SWAP_LE32(EXT2_FEATURE_INCOMPAT_FILETYPE); 278 sb->feature_ro_compat = SWAP_LE32(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER); 279 280 create_uuid(sb->uuid); 281 282 // TODO If we're called as mke3fs or mkfs.ext3, do a journal. 283 284 //if (strchr(toys.which->name,'3')) 285 // sb->feature_compat |= SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL); 286} 287 288// Does this group contain a superblock backup (and group descriptor table)? 289static int is_sb_group(uint32_t group) 290{ 291 int i; 292 293 // Superblock backups are on groups 0, 1, and powers of 3, 5, and 7. 294 if(!group || group==1) return 1; 295 for (i=3; i<9; i+=2) { 296 int j = i; 297 while (j<group) j*=i; 298 if (j==group) return 1; 299 } 300 return 0; 301} 302 303 304// Number of blocks used in group by optional superblock/group list backup. 305static int group_superblock_overhead(uint32_t group) 306{ 307 int used; 308 309 if (!is_sb_group(group)) return 0; 310 311 // How many blocks does the group descriptor table take up? 312 used = TT.groups * sizeof(struct ext2_group); 313 used += TT.blocksize - 1; 314 used /= TT.blocksize; 315 // Plus the superblock itself. 316 used++; 317 // And a corner case. 318 if (!group && TT.blocksize == 1024) used++; 319 320 return used; 321} 322 323// Number of blocks used in group to store superblock/group/inode list 324static int group_overhead(uint32_t group) 325{ 326 // Return superblock backup overhead (if any), plus block/inode 327 // allocation bitmaps, plus inode tables. 328 return group_superblock_overhead(group) + 2 + get_inodespg(TT.inodespg) 329 / (TT.blocksize/sizeof(struct ext2_inode)); 330} 331 332// In bitmap "array" set "len" bits starting at position "start" (from 0). 333static void bits_set(char *array, int start, int len) 334{ 335 while(len) { 336 if ((start&7) || len<8) { 337 array[start/8]|=(1<<(start&7)); 338 start++; 339 len--; 340 } else { 341 array[start/8]=255; 342 start+=8; 343 len-=8; 344 } 345 } 346} 347 348// Seek past len bytes (to maintain sparse file), or write zeroes if output 349// not seekable 350static void put_zeroes(int len) 351{ 352 if(-1 == lseek(TT.fsfd, len, SEEK_SET)) { 353 memset(toybuf, 0, sizeof(toybuf)); 354 while (len) { 355 int out = len > sizeof(toybuf) ? sizeof(toybuf) : len; 356 xwrite(TT.fsfd, toybuf, out); 357 len -= out; 358 } 359 } 360} 361 362// Fill out an inode structure from struct stat info in dirtree. 363static void fill_inode(struct ext2_inode *in, struct dirtree *that) 364{ 365 uint32_t fbu[15]; 366 int temp; 367 368 file_blocks_used(that->st.st_size, fbu); 369 370 // If that inode needs data blocks allocated to it. 371 if (that->st.st_size) { 372 int i, group = TT.nextblock/TT.blockbits; 373 374 // TODO: teach this about indirect blocks. 375 for (i=0; i<15; i++) { 376 // If we just jumped into a new group, skip group overhead blocks. 377 while (group >= TT.nextgroup) 378 TT.nextblock += group_overhead(TT.nextgroup++); 379 } 380 } 381 // TODO : S_ISREG/DIR/CHR/BLK/FIFO/LNK/SOCK(m) 382 in->mode = SWAP_LE32(that->st.st_mode); 383 384 in->uid = SWAP_LE16(that->st.st_uid & 0xFFFF); 385 in->uid_high = SWAP_LE16(that->st.st_uid >> 16); 386 in->gid = SWAP_LE16(that->st.st_gid & 0xFFFF); 387 in->gid_high = SWAP_LE16(that->st.st_gid >> 16); 388 in->size = SWAP_LE32(that->st.st_size & 0xFFFFFFFF); 389 390 // Contortions to make the compiler not generate a warning for x>>32 391 // when x is 32 bits. The optimizer should clean this up. 392 if (sizeof(that->st.st_size) > 4) temp = 32; 393 else temp = 0; 394 if (temp) in->dir_acl = SWAP_LE32(that->st.st_size >> temp); 395 396 in->atime = SWAP_LE32(that->st.st_atime); 397 in->ctime = SWAP_LE32(that->st.st_ctime); 398 in->mtime = SWAP_LE32(that->st.st_mtime); 399 400 in->links_count = SWAP_LE16(that->st.st_nlink); 401 in->blocks = SWAP_LE32(that->st.st_blocks); 402 // in->faddr 403} 404 405// Works like an archiver. 406// The first argument is the name of the file to create. If it already 407// exists, that size will be used. 408 409void mke2fs_main(void) 410{ 411 int i, temp; 412 off_t length; 413 uint32_t usedblocks, usedinodes, dtiblk, dtbblk; 414 struct dirtree *dti, *dtb; 415 416 // Handle command line arguments. 417 418 if (toys.optargs[1]) { 419 sscanf(toys.optargs[1], "%u", &TT.blocks); 420 temp = O_RDWR|O_CREAT; 421 } else temp = O_RDWR; 422 if (!TT.reserved_percent) TT.reserved_percent = 5; 423 424 // TODO: Check if filesystem is mounted here 425 426 // For mke?fs, open file. For gene?fs, create file. 427 TT.fsfd = xcreate(*toys.optargs, temp, 0777); 428 429 // Determine appropriate block size and block count from file length. 430 // (If no length, default to 4k. They can override it on the cmdline.) 431 432 length = fdlength(TT.fsfd); 433 if (!TT.blocksize) TT.blocksize = (length && length < 1<<29) ? 1024 : 4096; 434 TT.blockbits = 8*TT.blocksize; 435 if (!TT.blocks) TT.blocks = length/TT.blocksize; 436 437 // Collect gene2fs list or lost+found, calculate requirements. 438 439 if (TT.gendir) { 440 strncpy(toybuf, TT.gendir, sizeof(toybuf)); 441 dti = dirtree_read(toybuf, dirtree_notdotdot); 442 } else { 443 dti = xzalloc(sizeof(struct dirtree)+11); 444 strcpy(dti->name, "lost+found"); 445 dti->st.st_mode = S_IFDIR|0755; 446 dti->st.st_ctime = dti->st.st_mtime = time(NULL); 447 } 448 449 // Add root directory inode. This is iterated through for when finding 450 // blocks, but not when finding inodes. The tree's parent pointers don't 451 // point back into this. 452 453 dtb = xzalloc(sizeof(struct dirtree)+1); 454 dtb->st.st_mode = S_IFDIR|0755; 455 dtb->st.st_ctime = dtb->st.st_mtime = time(NULL); 456 dtb->child = dti; 457 458 // Figure out how much space is used by preset files 459 length = check_treesize(dtb, &(dtb->st.st_size)); 460 check_treelinks(dtb); 461 462 // Figure out how many total inodes we need. 463 464 if (!TT.inodes) { 465 if (!TT.bytes_per_inode) TT.bytes_per_inode = 8192; 466 TT.inodes = (TT.blocks * (uint64_t)TT.blocksize) / TT.bytes_per_inode; 467 } 468 469 // If we're generating a filesystem and have no idea how many blocks it 470 // needs, start with a minimal guess, find the overhead of that many 471 // groups, and loop until this is enough groups to store this many blocks. 472 if (!TT.blocks) TT.groups = (TT.treeblocks/TT.blockbits)+1; 473 else TT.groups = div_round_up(TT.blocks, TT.blockbits); 474 475 for (;;) { 476 temp = TT.treeblocks; 477 478 for (i = 0; i<TT.groups; i++) temp += group_overhead(i); 479 480 if (TT.blocks) { 481 if (TT.blocks < temp) error_exit("Not enough space.\n"); 482 break; 483 } 484 if (temp <= TT.groups * TT.blockbits) { 485 TT.blocks = temp; 486 break; 487 } 488 TT.groups++; 489 } 490 TT.freeblocks = TT.blocks - temp; 491 492 // Now we know all the TT data, initialize superblock structure. 493 494 init_superblock(&TT.sb); 495 496 // Start writing. Skip the first 1k to avoid the boot sector (if any). 497 put_zeroes(1024); 498 499 // Loop through block groups, write out each one. 500 dtiblk = dtbblk = usedblocks = usedinodes = 0; 501 for (i=0; i<TT.groups; i++) { 502 struct ext2_inode *in = (struct ext2_inode *)toybuf; 503 uint32_t start, itable, used, end; 504 int j, slot; 505 506 // Where does this group end? 507 end = TT.blockbits; 508 if ((i+1)*TT.blockbits > TT.blocks) end = TT.blocks & (TT.blockbits-1); 509 510 // Blocks used by inode table 511 itable = (TT.inodespg*sizeof(struct ext2_inode))/TT.blocksize; 512 513 // If a superblock goes here, write it out. 514 start = group_superblock_overhead(i); 515 if (start) { 516 struct ext2_group *bg = (struct ext2_group *)toybuf; 517 int treeblocks = TT.treeblocks, treeinodes = TT.treeinodes; 518 519 TT.sb.block_group_nr = SWAP_LE16(i); 520 521 // Write superblock and pad it up to block size 522 xwrite(TT.fsfd, &TT.sb, sizeof(struct ext2_superblock)); 523 temp = TT.blocksize - sizeof(struct ext2_superblock); 524 if (!i && TT.blocksize > 1024) temp -= 1024; 525 memset(toybuf, 0, TT.blocksize); 526 xwrite(TT.fsfd, toybuf, temp); 527 528 // Loop through groups to write group descriptor table. 529 for(j=0; j<TT.groups; j++) { 530 531 // Figure out what sector this group starts in. 532 used = group_superblock_overhead(j); 533 534 // Find next array slot in this block (flush block if full). 535 slot = j % (TT.blocksize/sizeof(struct ext2_group)); 536 if (!slot) { 537 if (j) xwrite(TT.fsfd, bg, TT.blocksize); 538 memset(bg, 0, TT.blocksize); 539 } 540 541 // How many free inodes in this group? 542 temp = TT.inodespg; 543 if (!i) temp -= INODES_RESERVED; 544 if (temp > treeinodes) { 545 treeinodes -= temp; 546 temp = 0; 547 } else { 548 temp -= treeinodes; 549 treeinodes = 0; 550 } 551 bg[slot].free_inodes_count = SWAP_LE16(temp); 552 553 // How many free blocks in this group? 554 temp = TT.inodespg/(TT.blocksize/sizeof(struct ext2_inode)) + 2; 555 temp = end-used-temp; 556 if (temp > treeblocks) { 557 treeblocks -= temp; 558 temp = 0; 559 } else { 560 temp -= treeblocks; 561 treeblocks = 0; 562 } 563 bg[slot].free_blocks_count = SWAP_LE32(temp); 564 565 // Fill out rest of group structure 566 used += j*TT.blockbits; 567 bg[slot].block_bitmap = SWAP_LE32(used++); 568 bg[slot].inode_bitmap = SWAP_LE32(used++); 569 bg[slot].inode_table = SWAP_LE32(used); 570 bg[slot].used_dirs_count = 0; // (TODO) 571 } 572 xwrite(TT.fsfd, bg, TT.blocksize); 573 } 574 575 // Now write out stuff that every block group has. 576 577 // Write block usage bitmap 578 579 start += 2 + itable; 580 memset(toybuf, 0, TT.blocksize); 581 bits_set(toybuf, 0, start); 582 bits_set(toybuf, end, TT.blockbits-end); 583 temp = TT.treeblocks - usedblocks; 584 if (temp) { 585 if (end-start > temp) temp = end-start; 586 bits_set(toybuf, start, temp); 587 } 588 xwrite(TT.fsfd, toybuf, TT.blocksize); 589 590 // Write inode bitmap 591 memset(toybuf, 0, TT.blocksize); 592 j = 0; 593 if (!i) bits_set(toybuf, 0, j = INODES_RESERVED); 594 bits_set(toybuf, TT.inodespg, slot = TT.blockbits-TT.inodespg); 595 temp = TT.treeinodes - usedinodes; 596 if (temp) { 597 if (slot-j > temp) temp = slot-j; 598 bits_set(toybuf, j, temp); 599 } 600 xwrite(TT.fsfd, toybuf, TT.blocksize); 601 602 // Write inode table for this group (TODO) 603 for (j = 0; j<TT.inodespg; j++) { 604 slot = j % (TT.blocksize/sizeof(struct ext2_inode)); 605 if (!slot) { 606 if (j) xwrite(TT.fsfd, in, TT.blocksize); 607 memset(in, 0, TT.blocksize); 608 } 609 if (!i && j<INODES_RESERVED) { 610 // Write root inode 611 if (j == 2) fill_inode(in+slot, dtb); 612 } else if (dti) { 613 fill_inode(in+slot, dti); 614 dti = treenext(dti); 615 } 616 } 617 xwrite(TT.fsfd, in, TT.blocksize); 618 619 while (dtb) { 620 // TODO write index data block 621 // TODO write root directory data block 622 // TODO write directory data block 623 // TODO write file data block 624 put_zeroes(TT.blocksize); 625 start++; 626 if (start == end) break; 627 } 628 // Write data blocks (TODO) 629 put_zeroes((end-start) * TT.blocksize); 630 } 631} 632