1/* 2 * GRUB -- GRand Unified Bootloader 3 * Copyright (C) 1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc. 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18 */ 19/* 20 * Copyright 2010 Sun Microsystems, Inc. All rights reserved. 21 * Use is subject to license terms. 22 */ 23 24/* 25 * The zfs plug-in routines for GRUB are: 26 * 27 * zfs_mount() - locates a valid uberblock of the root pool and reads 28 * in its MOS at the memory address MOS. 29 * 30 * zfs_open() - locates a plain file object by following the MOS 31 * and places its dnode at the memory address DNODE. 32 * 33 * zfs_read() - read in the data blocks pointed by the DNODE. 34 * 35 * ZFS_SCRATCH is used as a working area. 36 * 37 * (memory addr) MOS DNODE ZFS_SCRATCH 38 * | | | 39 * +-------V---------V----------V---------------+ 40 * memory | | dnode | dnode | scratch | 41 * | | 512B | 512B | area | 42 * +--------------------------------------------+ 43 */ 44 45#ifdef FSYS_ZFS 46 47#include "shared.h" 48#include "filesys.h" 49#include "fsys_zfs.h" 50 51/* cache for a file block of the currently zfs_open()-ed file */ 52static void *file_buf = NULL; 53static uint64_t file_start = 0; 54static uint64_t file_end = 0; 55 56/* cache for a dnode block */ 57static dnode_phys_t *dnode_buf = NULL; 58static dnode_phys_t *dnode_mdn = NULL; 59static uint64_t dnode_start = 0; 60static uint64_t dnode_end = 0; 61 62static uint64_t pool_guid = 0; 63static uberblock_t current_uberblock; 64static char *stackbase; 65 66decomp_entry_t decomp_table[ZIO_COMPRESS_FUNCTIONS] = 67{ 68 {"inherit", 0}, /* ZIO_COMPRESS_INHERIT */ 69 {"on", lzjb_decompress}, /* ZIO_COMPRESS_ON */ 70 {"off", 0}, /* ZIO_COMPRESS_OFF */ 71 {"lzjb", lzjb_decompress}, /* ZIO_COMPRESS_LZJB */ 72 {"empty", 0} /* ZIO_COMPRESS_EMPTY */ 73}; 74 75static int zio_read_data(blkptr_t *bp, void *buf, char *stack); 76 77/* 78 * Our own version of bcmp(). 79 */ 80static int 81zfs_bcmp(const void *s1, const void *s2, size_t n) 82{ 83 const uchar_t *ps1 = s1; 84 const uchar_t *ps2 = s2; 85 86 if (s1 != s2 && n != 0) { 87 do { 88 if (*ps1++ != *ps2++) 89 return (1); 90 } while (--n != 0); 91 } 92 93 return (0); 94} 95 96/* 97 * Our own version of log2(). Same thing as highbit()-1. 98 */ 99static int 100zfs_log2(uint64_t num) 101{ 102 int i = 0; 103 104 while (num > 1) { 105 i++; 106 num = num >> 1; 107 } 108 109 return (i); 110} 111 112/* Checksum Functions */ 113static void 114zio_checksum_off(const void *buf, uint64_t size, zio_cksum_t *zcp) 115{ 116 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 117} 118 119/* Checksum Table and Values */ 120zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = { 121 NULL, NULL, 0, 0, "inherit", 122 NULL, NULL, 0, 0, "on", 123 zio_checksum_off, zio_checksum_off, 0, 0, "off", 124 zio_checksum_SHA256, zio_checksum_SHA256, 1, 1, "label", 125 zio_checksum_SHA256, zio_checksum_SHA256, 1, 1, "gang_header", 126 NULL, NULL, 0, 0, "zilog", 127 fletcher_2_native, fletcher_2_byteswap, 0, 0, "fletcher2", 128 fletcher_4_native, fletcher_4_byteswap, 1, 0, "fletcher4", 129 zio_checksum_SHA256, zio_checksum_SHA256, 1, 0, "SHA256", 130 NULL, NULL, 0, 0, "zilog2", 131}; 132 133/* 134 * zio_checksum_verify: Provides support for checksum verification. 135 * 136 * Fletcher2, Fletcher4, and SHA256 are supported. 137 * 138 * Return: 139 * -1 = Failure 140 * 0 = Success 141 */ 142static int 143zio_checksum_verify(blkptr_t *bp, char *data, int size) 144{ 145 zio_cksum_t zc = bp->blk_cksum; 146 uint32_t checksum = BP_GET_CHECKSUM(bp); 147 int byteswap = BP_SHOULD_BYTESWAP(bp); 148 zio_eck_t *zec = (zio_eck_t *)(data + size) - 1; 149 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 150 zio_cksum_t actual_cksum, expected_cksum; 151 152 /* byteswap is not supported */ 153 if (byteswap) 154 return (-1); 155 156 if (checksum >= ZIO_CHECKSUM_FUNCTIONS || ci->ci_func[0] == NULL) 157 return (-1); 158 159 if (ci->ci_eck) { 160 expected_cksum = zec->zec_cksum; 161 zec->zec_cksum = zc; 162 ci->ci_func[0](data, size, &actual_cksum); 163 zec->zec_cksum = expected_cksum; 164 zc = expected_cksum; 165 166 } else { 167 ci->ci_func[byteswap](data, size, &actual_cksum); 168 } 169 170 if ((actual_cksum.zc_word[0] - zc.zc_word[0]) | 171 (actual_cksum.zc_word[1] - zc.zc_word[1]) | 172 (actual_cksum.zc_word[2] - zc.zc_word[2]) | 173 (actual_cksum.zc_word[3] - zc.zc_word[3])) 174 return (-1); 175 176 return (0); 177} 178 179/* 180 * vdev_label_start returns the physical disk offset (in bytes) of 181 * label "l". 182 */ 183static uint64_t 184vdev_label_start(uint64_t psize, int l) 185{ 186 return (l * sizeof (vdev_label_t) + (l < VDEV_LABELS / 2 ? 187 0 : psize - VDEV_LABELS * sizeof (vdev_label_t))); 188} 189 190/* 191 * vdev_uberblock_compare takes two uberblock structures and returns an integer 192 * indicating the more recent of the two. 193 * Return Value = 1 if ub2 is more recent 194 * Return Value = -1 if ub1 is more recent 195 * The most recent uberblock is determined using its transaction number and 196 * timestamp. The uberblock with the highest transaction number is 197 * considered "newer". If the transaction numbers of the two blocks match, the 198 * timestamps are compared to determine the "newer" of the two. 199 */ 200static int 201vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2) 202{ 203 if (ub1->ub_txg < ub2->ub_txg) 204 return (-1); 205 if (ub1->ub_txg > ub2->ub_txg) 206 return (1); 207 208 if (ub1->ub_timestamp < ub2->ub_timestamp) 209 return (-1); 210 if (ub1->ub_timestamp > ub2->ub_timestamp) 211 return (1); 212 213 return (0); 214} 215 216/* 217 * Three pieces of information are needed to verify an uberblock: the magic 218 * number, the version number, and the checksum. 219 * 220 * Currently Implemented: version number, magic number 221 * Need to Implement: checksum 222 * 223 * Return: 224 * 0 - Success 225 * -1 - Failure 226 */ 227static int 228uberblock_verify(uberblock_phys_t *ub, uint64_t offset) 229{ 230 231 uberblock_t *uber = &ub->ubp_uberblock; 232 blkptr_t bp; 233 234 BP_ZERO(&bp); 235 BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL); 236 BP_SET_BYTEORDER(&bp, ZFS_HOST_BYTEORDER); 237 ZIO_SET_CHECKSUM(&bp.blk_cksum, offset, 0, 0, 0); 238 239 if (zio_checksum_verify(&bp, (char *)ub, UBERBLOCK_SIZE) != 0) 240 return (-1); 241 242 if (uber->ub_magic == UBERBLOCK_MAGIC && 243 uber->ub_version > 0 && uber->ub_version <= SPA_VERSION) 244 return (0); 245 246 return (-1); 247} 248 249/* 250 * Find the best uberblock. 251 * Return: 252 * Success - Pointer to the best uberblock. 253 * Failure - NULL 254 */ 255static uberblock_phys_t * 256find_bestub(uberblock_phys_t *ub_array, uint64_t sector) 257{ 258 uberblock_phys_t *ubbest = NULL; 259 uint64_t offset; 260 int i; 261 262 for (i = 0; i < (VDEV_UBERBLOCK_RING >> VDEV_UBERBLOCK_SHIFT); i++) { 263 offset = (sector << SPA_MINBLOCKSHIFT) + 264 VDEV_UBERBLOCK_OFFSET(i); 265 if (uberblock_verify(&ub_array[i], offset) == 0) { 266 if (ubbest == NULL) { 267 ubbest = &ub_array[i]; 268 } else if (vdev_uberblock_compare( 269 &(ub_array[i].ubp_uberblock), 270 &(ubbest->ubp_uberblock)) > 0) { 271 ubbest = &ub_array[i]; 272 } 273 } 274 } 275 276 return (ubbest); 277} 278 279/* 280 * Read a block of data based on the gang block address dva, 281 * and put its data in buf. 282 * 283 * Return: 284 * 0 - success 285 * 1 - failure 286 */ 287static int 288zio_read_gang(blkptr_t *bp, dva_t *dva, void *buf, char *stack) 289{ 290 zio_gbh_phys_t *zio_gb; 291 uint64_t offset, sector; 292 blkptr_t tmpbp; 293 int i; 294 295 zio_gb = (zio_gbh_phys_t *)stack; 296 stack += SPA_GANGBLOCKSIZE; 297 offset = DVA_GET_OFFSET(dva); 298 sector = DVA_OFFSET_TO_PHYS_SECTOR(offset); 299 300 /* read in the gang block header */ 301 if (devread(sector, 0, SPA_GANGBLOCKSIZE, (char *)zio_gb) == 0) { 302 grub_printf("failed to read in a gang block header\n"); 303 return (1); 304 } 305 306 /* self checksuming the gang block header */ 307 BP_ZERO(&tmpbp); 308 BP_SET_CHECKSUM(&tmpbp, ZIO_CHECKSUM_GANG_HEADER); 309 BP_SET_BYTEORDER(&tmpbp, ZFS_HOST_BYTEORDER); 310 ZIO_SET_CHECKSUM(&tmpbp.blk_cksum, DVA_GET_VDEV(dva), 311 DVA_GET_OFFSET(dva), bp->blk_birth, 0); 312 if (zio_checksum_verify(&tmpbp, (char *)zio_gb, SPA_GANGBLOCKSIZE)) { 313 grub_printf("failed to checksum a gang block header\n"); 314 return (1); 315 } 316 317 for (i = 0; i < SPA_GBH_NBLKPTRS; i++) { 318 if (zio_gb->zg_blkptr[i].blk_birth == 0) 319 continue; 320 321 if (zio_read_data(&zio_gb->zg_blkptr[i], buf, stack)) 322 return (1); 323 buf += BP_GET_PSIZE(&zio_gb->zg_blkptr[i]); 324 } 325 326 return (0); 327} 328 329/* 330 * Read in a block of raw data to buf. 331 * 332 * Return: 333 * 0 - success 334 * 1 - failure 335 */ 336static int 337zio_read_data(blkptr_t *bp, void *buf, char *stack) 338{ 339 int i, psize; 340 341 psize = BP_GET_PSIZE(bp); 342 343 /* pick a good dva from the block pointer */ 344 for (i = 0; i < SPA_DVAS_PER_BP; i++) { 345 uint64_t offset, sector; 346 347 if (bp->blk_dva[i].dva_word[0] == 0 && 348 bp->blk_dva[i].dva_word[1] == 0) 349 continue; 350 351 if (DVA_GET_GANG(&bp->blk_dva[i])) { 352 if (zio_read_gang(bp, &bp->blk_dva[i], buf, stack) == 0) 353 return (0); 354 } else { 355 /* read in a data block */ 356 offset = DVA_GET_OFFSET(&bp->blk_dva[i]); 357 sector = DVA_OFFSET_TO_PHYS_SECTOR(offset); 358 if (devread(sector, 0, psize, buf)) 359 return (0); 360 } 361 } 362 363 return (1); 364} 365 366/* 367 * Read in a block of data, verify its checksum, decompress if needed, 368 * and put the uncompressed data in buf. 369 * 370 * Return: 371 * 0 - success 372 * errnum - failure 373 */ 374static int 375zio_read(blkptr_t *bp, void *buf, char *stack) 376{ 377 int lsize, psize, comp; 378 char *retbuf; 379 380 comp = BP_GET_COMPRESS(bp); 381 lsize = BP_GET_LSIZE(bp); 382 psize = BP_GET_PSIZE(bp); 383 384 if ((unsigned int)comp >= ZIO_COMPRESS_FUNCTIONS || 385 (comp != ZIO_COMPRESS_OFF && 386 decomp_table[comp].decomp_func == NULL)) { 387 grub_printf("compression algorithm not supported\n"); 388 return (ERR_FSYS_CORRUPT); 389 } 390 391 if ((char *)buf < stack && ((char *)buf) + lsize > stack) { 392 grub_printf("not enough memory allocated\n"); 393 return (ERR_WONT_FIT); 394 } 395 396 retbuf = buf; 397 if (comp != ZIO_COMPRESS_OFF) { 398 buf = stack; 399 stack += psize; 400 } 401 402 if (zio_read_data(bp, buf, stack)) { 403 grub_printf("zio_read_data failed\n"); 404 return (ERR_FSYS_CORRUPT); 405 } 406 407 if (zio_checksum_verify(bp, buf, psize) != 0) { 408 grub_printf("checksum verification failed\n"); 409 return (ERR_FSYS_CORRUPT); 410 } 411 412 if (comp != ZIO_COMPRESS_OFF) 413 decomp_table[comp].decomp_func(buf, retbuf, psize, lsize); 414 415 return (0); 416} 417 418/* 419 * Get the block from a block id. 420 * push the block onto the stack. 421 * 422 * Return: 423 * 0 - success 424 * errnum - failure 425 */ 426static int 427dmu_read(dnode_phys_t *dn, uint64_t blkid, void *buf, char *stack) 428{ 429 int idx, level; 430 blkptr_t *bp_array = dn->dn_blkptr; 431 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 432 blkptr_t *bp, *tmpbuf; 433 434 bp = (blkptr_t *)stack; 435 stack += sizeof (blkptr_t); 436 437 tmpbuf = (blkptr_t *)stack; 438 stack += 1<<dn->dn_indblkshift; 439 440 for (level = dn->dn_nlevels - 1; level >= 0; level--) { 441 idx = (blkid >> (epbs * level)) & ((1<<epbs)-1); 442 *bp = bp_array[idx]; 443 if (level == 0) 444 tmpbuf = buf; 445 if (BP_IS_HOLE(bp)) { 446 grub_memset(buf, 0, 447 dn->dn_datablkszsec << SPA_MINBLOCKSHIFT); 448 break; 449 } else if (errnum = zio_read(bp, tmpbuf, stack)) { 450 return (errnum); 451 } 452 453 bp_array = tmpbuf; 454 } 455 456 return (0); 457} 458 459/* 460 * mzap_lookup: Looks up property described by "name" and returns the value 461 * in "value". 462 * 463 * Return: 464 * 0 - success 465 * errnum - failure 466 */ 467static int 468mzap_lookup(mzap_phys_t *zapobj, int objsize, char *name, 469 uint64_t *value) 470{ 471 int i, chunks; 472 mzap_ent_phys_t *mzap_ent = zapobj->mz_chunk; 473 474 chunks = objsize/MZAP_ENT_LEN - 1; 475 for (i = 0; i < chunks; i++) { 476 if (grub_strcmp(mzap_ent[i].mze_name, name) == 0) { 477 *value = mzap_ent[i].mze_value; 478 return (0); 479 } 480 } 481 482 return (ERR_FSYS_CORRUPT); 483} 484 485static uint64_t 486zap_hash(uint64_t salt, const char *name) 487{ 488 static uint64_t table[256]; 489 const uint8_t *cp; 490 uint8_t c; 491 uint64_t crc = salt; 492 493 if (table[128] == 0) { 494 uint64_t *ct; 495 int i, j; 496 for (i = 0; i < 256; i++) { 497 for (ct = table + i, *ct = i, j = 8; j > 0; j--) 498 *ct = (*ct >> 1) ^ (-(*ct & 1) & 499 ZFS_CRC64_POLY); 500 } 501 } 502 503 if (crc == 0 || table[128] != ZFS_CRC64_POLY) { 504 errnum = ERR_FSYS_CORRUPT; 505 return (0); 506 } 507 508 for (cp = (const uint8_t *)name; (c = *cp) != '\0'; cp++) 509 crc = (crc >> 8) ^ table[(crc ^ c) & 0xFF]; 510 511 /* 512 * Only use 28 bits, since we need 4 bits in the cookie for the 513 * collision differentiator. We MUST use the high bits, since 514 * those are the onces that we first pay attention to when 515 * chosing the bucket. 516 */ 517 crc &= ~((1ULL << (64 - 28)) - 1); 518 519 return (crc); 520} 521 522/* 523 * Only to be used on 8-bit arrays. 524 * array_len is actual len in bytes (not encoded le_value_length). 525 * buf is null-terminated. 526 */ 527static int 528zap_leaf_array_equal(zap_leaf_phys_t *l, int blksft, int chunk, 529 int array_len, const char *buf) 530{ 531 int bseen = 0; 532 533 while (bseen < array_len) { 534 struct zap_leaf_array *la = 535 &ZAP_LEAF_CHUNK(l, blksft, chunk).l_array; 536 int toread = MIN(array_len - bseen, ZAP_LEAF_ARRAY_BYTES); 537 538 if (chunk >= ZAP_LEAF_NUMCHUNKS(blksft)) 539 return (0); 540 541 if (zfs_bcmp(la->la_array, buf + bseen, toread) != 0) 542 break; 543 chunk = la->la_next; 544 bseen += toread; 545 } 546 return (bseen == array_len); 547} 548 549/* 550 * Given a zap_leaf_phys_t, walk thru the zap leaf chunks to get the 551 * value for the property "name". 552 * 553 * Return: 554 * 0 - success 555 * errnum - failure 556 */ 557static int 558zap_leaf_lookup(zap_leaf_phys_t *l, int blksft, uint64_t h, 559 const char *name, uint64_t *value) 560{ 561 uint16_t chunk; 562 struct zap_leaf_entry *le; 563 564 /* Verify if this is a valid leaf block */ 565 if (l->l_hdr.lh_block_type != ZBT_LEAF) 566 return (ERR_FSYS_CORRUPT); 567 if (l->l_hdr.lh_magic != ZAP_LEAF_MAGIC) 568 return (ERR_FSYS_CORRUPT); 569 570 for (chunk = l->l_hash[LEAF_HASH(blksft, h)]; 571 chunk != CHAIN_END; chunk = le->le_next) { 572 573 if (chunk >= ZAP_LEAF_NUMCHUNKS(blksft)) 574 return (ERR_FSYS_CORRUPT); 575 576 le = ZAP_LEAF_ENTRY(l, blksft, chunk); 577 578 /* Verify the chunk entry */ 579 if (le->le_type != ZAP_CHUNK_ENTRY) 580 return (ERR_FSYS_CORRUPT); 581 582 if (le->le_hash != h) 583 continue; 584 585 if (zap_leaf_array_equal(l, blksft, le->le_name_chunk, 586 le->le_name_length, name)) { 587 588 struct zap_leaf_array *la; 589 uint8_t *ip; 590 591 if (le->le_int_size != 8 || le->le_value_length != 1) 592 return (ERR_FSYS_CORRUPT); 593 594 /* get the uint64_t property value */ 595 la = &ZAP_LEAF_CHUNK(l, blksft, 596 le->le_value_chunk).l_array; 597 ip = la->la_array; 598 599 *value = (uint64_t)ip[0] << 56 | (uint64_t)ip[1] << 48 | 600 (uint64_t)ip[2] << 40 | (uint64_t)ip[3] << 32 | 601 (uint64_t)ip[4] << 24 | (uint64_t)ip[5] << 16 | 602 (uint64_t)ip[6] << 8 | (uint64_t)ip[7]; 603 604 return (0); 605 } 606 } 607 608 return (ERR_FSYS_CORRUPT); 609} 610 611/* 612 * Fat ZAP lookup 613 * 614 * Return: 615 * 0 - success 616 * errnum - failure 617 */ 618static int 619fzap_lookup(dnode_phys_t *zap_dnode, zap_phys_t *zap, 620 char *name, uint64_t *value, char *stack) 621{ 622 zap_leaf_phys_t *l; 623 uint64_t hash, idx, blkid; 624 int blksft = zfs_log2(zap_dnode->dn_datablkszsec << DNODE_SHIFT); 625 626 /* Verify if this is a fat zap header block */ 627 if (zap->zap_magic != (uint64_t)ZAP_MAGIC || 628 zap->zap_flags != 0) 629 return (ERR_FSYS_CORRUPT); 630 631 hash = zap_hash(zap->zap_salt, name); 632 if (errnum) 633 return (errnum); 634 635 /* get block id from index */ 636 if (zap->zap_ptrtbl.zt_numblks != 0) { 637 /* external pointer tables not supported */ 638 return (ERR_FSYS_CORRUPT); 639 } 640 idx = ZAP_HASH_IDX(hash, zap->zap_ptrtbl.zt_shift); 641 blkid = ((uint64_t *)zap)[idx + (1<<(blksft-3-1))]; 642 643 /* Get the leaf block */ 644 l = (zap_leaf_phys_t *)stack; 645 stack += 1<<blksft; 646 if ((1<<blksft) < sizeof (zap_leaf_phys_t)) 647 return (ERR_FSYS_CORRUPT); 648 if (errnum = dmu_read(zap_dnode, blkid, l, stack)) 649 return (errnum); 650 651 return (zap_leaf_lookup(l, blksft, hash, name, value)); 652} 653 654/* 655 * Read in the data of a zap object and find the value for a matching 656 * property name. 657 * 658 * Return: 659 * 0 - success 660 * errnum - failure 661 */ 662static int 663zap_lookup(dnode_phys_t *zap_dnode, char *name, uint64_t *val, char *stack) 664{ 665 uint64_t block_type; 666 int size; 667 void *zapbuf; 668 669 /* Read in the first block of the zap object data. */ 670 zapbuf = stack; 671 size = zap_dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT; 672 stack += size; 673 674 if (errnum = dmu_read(zap_dnode, 0, zapbuf, stack)) 675 return (errnum); 676 677 block_type = *((uint64_t *)zapbuf); 678 679 if (block_type == ZBT_MICRO) { 680 return (mzap_lookup(zapbuf, size, name, val)); 681 } else if (block_type == ZBT_HEADER) { 682 /* this is a fat zap */ 683 return (fzap_lookup(zap_dnode, zapbuf, name, 684 val, stack)); 685 } 686 687 return (ERR_FSYS_CORRUPT); 688} 689 690/* 691 * Get the dnode of an object number from the metadnode of an object set. 692 * 693 * Input 694 * mdn - metadnode to get the object dnode 695 * objnum - object number for the object dnode 696 * buf - data buffer that holds the returning dnode 697 * stack - scratch area 698 * 699 * Return: 700 * 0 - success 701 * errnum - failure 702 */ 703static int 704dnode_get(dnode_phys_t *mdn, uint64_t objnum, uint8_t type, dnode_phys_t *buf, 705 char *stack) 706{ 707 uint64_t blkid, blksz; /* the block id this object dnode is in */ 708 int epbs; /* shift of number of dnodes in a block */ 709 int idx; /* index within a block */ 710 dnode_phys_t *dnbuf; 711 712 blksz = mdn->dn_datablkszsec << SPA_MINBLOCKSHIFT; 713 epbs = zfs_log2(blksz) - DNODE_SHIFT; 714 blkid = objnum >> epbs; 715 idx = objnum & ((1<<epbs)-1); 716 717 if (dnode_buf != NULL && dnode_mdn == mdn && 718 objnum >= dnode_start && objnum < dnode_end) { 719 grub_memmove(buf, &dnode_buf[idx], DNODE_SIZE); 720 VERIFY_DN_TYPE(buf, type); 721 return (0); 722 } 723 724 if (dnode_buf && blksz == 1<<DNODE_BLOCK_SHIFT) { 725 dnbuf = dnode_buf; 726 dnode_mdn = mdn; 727 dnode_start = blkid << epbs; 728 dnode_end = (blkid + 1) << epbs; 729 } else { 730 dnbuf = (dnode_phys_t *)stack; 731 stack += blksz; 732 } 733 734 if (errnum = dmu_read(mdn, blkid, (char *)dnbuf, stack)) 735 return (errnum); 736 737 grub_memmove(buf, &dnbuf[idx], DNODE_SIZE); 738 VERIFY_DN_TYPE(buf, type); 739 740 return (0); 741} 742 743/* 744 * Check if this is a special file that resides at the top 745 * dataset of the pool. Currently this is the GRUB menu, 746 * boot signature and boot signature backup. 747 * str starts with '/'. 748 */ 749static int 750is_top_dataset_file(char *str) 751{ 752 char *tptr; 753 754 if ((tptr = grub_strstr(str, "menu.lst")) && 755 (tptr[8] == '\0' || tptr[8] == ' ') && 756 *(tptr-1) == '/') 757 return (1); 758 759 if (grub_strncmp(str, BOOTSIGN_DIR"/", 760 grub_strlen(BOOTSIGN_DIR) + 1) == 0) 761 return (1); 762 763 if (grub_strcmp(str, BOOTSIGN_BACKUP) == 0) 764 return (1); 765 766 return (0); 767} 768 769/* 770 * Get the file dnode for a given file name where mdn is the meta dnode 771 * for this ZFS object set. When found, place the file dnode in dn. 772 * The 'path' argument will be mangled. 773 * 774 * Return: 775 * 0 - success 776 * errnum - failure 777 */ 778static int 779dnode_get_path(dnode_phys_t *mdn, char *path, dnode_phys_t *dn, 780 char *stack) 781{ 782 uint64_t objnum, version; 783 char *cname, ch; 784 785 if (errnum = dnode_get(mdn, MASTER_NODE_OBJ, DMU_OT_MASTER_NODE, 786 dn, stack)) 787 return (errnum); 788 789 if (errnum = zap_lookup(dn, ZPL_VERSION_STR, &version, stack)) 790 return (errnum); 791 if (version > ZPL_VERSION) 792 return (-1); 793 794 if (errnum = zap_lookup(dn, ZFS_ROOT_OBJ, &objnum, stack)) 795 return (errnum); 796 797 if (errnum = dnode_get(mdn, objnum, DMU_OT_DIRECTORY_CONTENTS, 798 dn, stack)) 799 return (errnum); 800 801 /* skip leading slashes */ 802 while (*path == '/') 803 path++; 804 805 while (*path && !isspace(*path)) { 806 807 /* get the next component name */ 808 cname = path; 809 while (*path && !isspace(*path) && *path != '/') 810 path++; 811 ch = *path; 812 *path = 0; /* ensure null termination */ 813 814 if (errnum = zap_lookup(dn, cname, &objnum, stack)) 815 return (errnum); 816 817 objnum = ZFS_DIRENT_OBJ(objnum); 818 if (errnum = dnode_get(mdn, objnum, 0, dn, stack)) 819 return (errnum); 820 821 *path = ch; 822 while (*path == '/') 823 path++; 824 } 825 826 /* We found the dnode for this file. Verify if it is a plain file. */ 827 VERIFY_DN_TYPE(dn, DMU_OT_PLAIN_FILE_CONTENTS); 828 829 return (0); 830} 831 832/* 833 * Get the default 'bootfs' property value from the rootpool. 834 * 835 * Return: 836 * 0 - success 837 * errnum -failure 838 */ 839static int 840get_default_bootfsobj(dnode_phys_t *mosmdn, uint64_t *obj, char *stack) 841{ 842 uint64_t objnum = 0; 843 dnode_phys_t *dn = (dnode_phys_t *)stack; 844 stack += DNODE_SIZE; 845 846 if (errnum = dnode_get(mosmdn, DMU_POOL_DIRECTORY_OBJECT, 847 DMU_OT_OBJECT_DIRECTORY, dn, stack)) 848 return (errnum); 849 850 /* 851 * find the object number for 'pool_props', and get the dnode 852 * of the 'pool_props'. 853 */ 854 if (zap_lookup(dn, DMU_POOL_PROPS, &objnum, stack)) 855 return (ERR_FILESYSTEM_NOT_FOUND); 856 857 if (errnum = dnode_get(mosmdn, objnum, DMU_OT_POOL_PROPS, dn, stack)) 858 return (errnum); 859 860 if (zap_lookup(dn, ZPOOL_PROP_BOOTFS, &objnum, stack)) 861 return (ERR_FILESYSTEM_NOT_FOUND); 862 863 if (!objnum) 864 return (ERR_FILESYSTEM_NOT_FOUND); 865 866 *obj = objnum; 867 return (0); 868} 869 870/* 871 * Given a MOS metadnode, get the metadnode of a given filesystem name (fsname), 872 * e.g. pool/rootfs, or a given object number (obj), e.g. the object number 873 * of pool/rootfs. 874 * 875 * If no fsname and no obj are given, return the DSL_DIR metadnode. 876 * If fsname is given, return its metadnode and its matching object number. 877 * If only obj is given, return the metadnode for this object number. 878 * 879 * Return: 880 * 0 - success 881 * errnum - failure 882 */ 883static int 884get_objset_mdn(dnode_phys_t *mosmdn, char *fsname, uint64_t *obj, 885 dnode_phys_t *mdn, char *stack) 886{ 887 uint64_t objnum, headobj; 888 char *cname, ch; 889 blkptr_t *bp; 890 objset_phys_t *osp; 891 int issnapshot = 0; 892 char *snapname; 893 894 if (fsname == NULL && obj) { 895 headobj = *obj; 896 goto skip; 897 } 898 899 if (errnum = dnode_get(mosmdn, DMU_POOL_DIRECTORY_OBJECT, 900 DMU_OT_OBJECT_DIRECTORY, mdn, stack)) 901 return (errnum); 902 903 if (errnum = zap_lookup(mdn, DMU_POOL_ROOT_DATASET, &objnum, 904 stack)) 905 return (errnum); 906 907 if (errnum = dnode_get(mosmdn, objnum, DMU_OT_DSL_DIR, mdn, stack)) 908 return (errnum); 909 910 if (fsname == NULL) { 911 headobj = 912 ((dsl_dir_phys_t *)DN_BONUS(mdn))->dd_head_dataset_obj; 913 goto skip; 914 } 915 916 /* take out the pool name */ 917 while (*fsname && !isspace(*fsname) && *fsname != '/') 918 fsname++; 919 920 while (*fsname && !isspace(*fsname)) { 921 uint64_t childobj; 922 923 while (*fsname == '/') 924 fsname++; 925 926 cname = fsname; 927 while (*fsname && !isspace(*fsname) && *fsname != '/') 928 fsname++; 929 ch = *fsname; 930 *fsname = 0; 931 932 snapname = cname; 933 while (*snapname && !isspace(*snapname) && *snapname != '@') 934 snapname++; 935 if (*snapname == '@') { 936 issnapshot = 1; 937 *snapname = 0; 938 } 939 childobj = 940 ((dsl_dir_phys_t *)DN_BONUS(mdn))->dd_child_dir_zapobj; 941 if (errnum = dnode_get(mosmdn, childobj, 942 DMU_OT_DSL_DIR_CHILD_MAP, mdn, stack)) 943 return (errnum); 944 945 if (zap_lookup(mdn, cname, &objnum, stack)) 946 return (ERR_FILESYSTEM_NOT_FOUND); 947 948 if (errnum = dnode_get(mosmdn, objnum, DMU_OT_DSL_DIR, 949 mdn, stack)) 950 return (errnum); 951 952 *fsname = ch; 953 if (issnapshot) 954 *snapname = '@'; 955 } 956 headobj = ((dsl_dir_phys_t *)DN_BONUS(mdn))->dd_head_dataset_obj; 957 if (obj) 958 *obj = headobj; 959 960skip: 961 if (errnum = dnode_get(mosmdn, headobj, DMU_OT_DSL_DATASET, mdn, stack)) 962 return (errnum); 963 if (issnapshot) { 964 uint64_t snapobj; 965 966 snapobj = ((dsl_dataset_phys_t *)DN_BONUS(mdn))-> 967 ds_snapnames_zapobj; 968 969 if (errnum = dnode_get(mosmdn, snapobj, 970 DMU_OT_DSL_DS_SNAP_MAP, mdn, stack)) 971 return (errnum); 972 if (zap_lookup(mdn, snapname + 1, &headobj, stack)) 973 return (ERR_FILESYSTEM_NOT_FOUND); 974 if (errnum = dnode_get(mosmdn, headobj, 975 DMU_OT_DSL_DATASET, mdn, stack)) 976 return (errnum); 977 if (obj) 978 *obj = headobj; 979 } 980 981 bp = &((dsl_dataset_phys_t *)DN_BONUS(mdn))->ds_bp; 982 osp = (objset_phys_t *)stack; 983 stack += sizeof (objset_phys_t); 984 if (errnum = zio_read(bp, osp, stack)) 985 return (errnum); 986 987 grub_memmove((char *)mdn, (char *)&osp->os_meta_dnode, DNODE_SIZE); 988 989 return (0); 990} 991 992/* 993 * For a given XDR packed nvlist, verify the first 4 bytes and move on. 994 * 995 * An XDR packed nvlist is encoded as (comments from nvs_xdr_create) : 996 * 997 * encoding method/host endian (4 bytes) 998 * nvl_version (4 bytes) 999 * nvl_nvflag (4 bytes) 1000 * encoded nvpairs: 1001 * encoded size of the nvpair (4 bytes) 1002 * decoded size of the nvpair (4 bytes) 1003 * name string size (4 bytes) 1004 * name string data (sizeof(NV_ALIGN4(string)) 1005 * data type (4 bytes) 1006 * # of elements in the nvpair (4 bytes) 1007 * data 1008 * 2 zero's for the last nvpair 1009 * (end of the entire list) (8 bytes) 1010 * 1011 * Return: 1012 * 0 - success 1013 * 1 - failure 1014 */ 1015static int 1016nvlist_unpack(char *nvlist, char **out) 1017{ 1018 /* Verify if the 1st and 2nd byte in the nvlist are valid. */ 1019 if (nvlist[0] != NV_ENCODE_XDR || nvlist[1] != HOST_ENDIAN) 1020 return (1); 1021 1022 nvlist += 4; 1023 *out = nvlist; 1024 return (0); 1025} 1026 1027static char * 1028nvlist_array(char *nvlist, int index) 1029{ 1030 int i, encode_size; 1031 1032 for (i = 0; i < index; i++) { 1033 /* skip the header, nvl_version, and nvl_nvflag */ 1034 nvlist = nvlist + 4 * 2; 1035 1036 while (encode_size = BSWAP_32(*(uint32_t *)nvlist)) 1037 nvlist += encode_size; /* goto the next nvpair */ 1038 1039 nvlist = nvlist + 4 * 2; /* skip the ending 2 zeros - 8 bytes */ 1040 } 1041 1042 return (nvlist); 1043} 1044 1045static int 1046nvlist_lookup_value(char *nvlist, char *name, void *val, int valtype, 1047 int *nelmp) 1048{ 1049 int name_len, type, slen, encode_size; 1050 char *nvpair, *nvp_name, *strval = val; 1051 uint64_t *intval = val; 1052 1053 /* skip the header, nvl_version, and nvl_nvflag */ 1054 nvlist = nvlist + 4 * 2; 1055 1056 /* 1057 * Loop thru the nvpair list 1058 * The XDR representation of an integer is in big-endian byte order. 1059 */ 1060 while (encode_size = BSWAP_32(*(uint32_t *)nvlist)) { 1061 1062 nvpair = nvlist + 4 * 2; /* skip the encode/decode size */ 1063 1064 name_len = BSWAP_32(*(uint32_t *)nvpair); 1065 nvpair += 4; 1066 1067 nvp_name = nvpair; 1068 nvpair = nvpair + ((name_len + 3) & ~3); /* align */ 1069 1070 type = BSWAP_32(*(uint32_t *)nvpair); 1071 nvpair += 4; 1072 1073 if ((grub_strncmp(nvp_name, name, name_len) == 0) && 1074 type == valtype) { 1075 int nelm; 1076 1077 if ((nelm = BSWAP_32(*(uint32_t *)nvpair)) < 1) 1078 return (1); 1079 nvpair += 4; 1080 1081 switch (valtype) { 1082 case DATA_TYPE_STRING: 1083 slen = BSWAP_32(*(uint32_t *)nvpair); 1084 nvpair += 4; 1085 grub_memmove(strval, nvpair, slen); 1086 strval[slen] = '\0'; 1087 return (0); 1088 1089 case DATA_TYPE_UINT64: 1090 *intval = BSWAP_64(*(uint64_t *)nvpair); 1091 return (0); 1092 1093 case DATA_TYPE_NVLIST: 1094 *(void **)val = (void *)nvpair; 1095 return (0); 1096 1097 case DATA_TYPE_NVLIST_ARRAY: 1098 *(void **)val = (void *)nvpair; 1099 if (nelmp) 1100 *nelmp = nelm; 1101 return (0); 1102 } 1103 } 1104 1105 nvlist += encode_size; /* goto the next nvpair */ 1106 } 1107 1108 return (1); 1109} 1110 1111/* 1112 * Check if this vdev is online and is in a good state. 1113 */ 1114static int 1115vdev_validate(char *nv) 1116{ 1117 uint64_t ival; 1118 1119 if (nvlist_lookup_value(nv, ZPOOL_CONFIG_OFFLINE, &ival, 1120 DATA_TYPE_UINT64, NULL) == 0 || 1121 nvlist_lookup_value(nv, ZPOOL_CONFIG_FAULTED, &ival, 1122 DATA_TYPE_UINT64, NULL) == 0 || 1123 nvlist_lookup_value(nv, ZPOOL_CONFIG_REMOVED, &ival, 1124 DATA_TYPE_UINT64, NULL) == 0) 1125 return (ERR_DEV_VALUES); 1126 1127 return (0); 1128} 1129 1130/* 1131 * Get a valid vdev pathname/devid from the boot device. 1132 * The caller should already allocate MAXPATHLEN memory for bootpath and devid. 1133 */ 1134static int 1135vdev_get_bootpath(char *nv, uint64_t inguid, char *devid, char *bootpath, 1136 int is_spare) 1137{ 1138 char type[16]; 1139 1140 if (nvlist_lookup_value(nv, ZPOOL_CONFIG_TYPE, &type, DATA_TYPE_STRING, 1141 NULL)) 1142 return (ERR_FSYS_CORRUPT); 1143 1144 if (strcmp(type, VDEV_TYPE_DISK) == 0) { 1145 uint64_t guid; 1146 1147 if (vdev_validate(nv) != 0) 1148 return (ERR_NO_BOOTPATH); 1149 1150 if (nvlist_lookup_value(nv, ZPOOL_CONFIG_GUID, 1151 &guid, DATA_TYPE_UINT64, NULL) != 0) 1152 return (ERR_NO_BOOTPATH); 1153 1154 if (guid != inguid) 1155 return (ERR_NO_BOOTPATH); 1156 1157 /* for a spare vdev, pick the disk labeled with "is_spare" */ 1158 if (is_spare) { 1159 uint64_t spare = 0; 1160 (void) nvlist_lookup_value(nv, ZPOOL_CONFIG_IS_SPARE, 1161 &spare, DATA_TYPE_UINT64, NULL); 1162 if (!spare) 1163 return (ERR_NO_BOOTPATH); 1164 } 1165 1166 if (nvlist_lookup_value(nv, ZPOOL_CONFIG_PHYS_PATH, 1167 bootpath, DATA_TYPE_STRING, NULL) != 0) 1168 bootpath[0] = '\0'; 1169 1170 if (nvlist_lookup_value(nv, ZPOOL_CONFIG_DEVID, 1171 devid, DATA_TYPE_STRING, NULL) != 0) 1172 devid[0] = '\0'; 1173 1174 if (strlen(bootpath) >= MAXPATHLEN || 1175 strlen(devid) >= MAXPATHLEN) 1176 return (ERR_WONT_FIT); 1177 1178 return (0); 1179 1180 } else if (strcmp(type, VDEV_TYPE_MIRROR) == 0 || 1181 strcmp(type, VDEV_TYPE_REPLACING) == 0 || 1182 (is_spare = (strcmp(type, VDEV_TYPE_SPARE) == 0))) { 1183 int nelm, i; 1184 char *child; 1185 1186 if (nvlist_lookup_value(nv, ZPOOL_CONFIG_CHILDREN, &child, 1187 DATA_TYPE_NVLIST_ARRAY, &nelm)) 1188 return (ERR_FSYS_CORRUPT); 1189 1190 for (i = 0; i < nelm; i++) { 1191 char *child_i; 1192 1193 child_i = nvlist_array(child, i); 1194 if (vdev_get_bootpath(child_i, inguid, devid, 1195 bootpath, is_spare) == 0) 1196 return (0); 1197 } 1198 } 1199 1200 return (ERR_NO_BOOTPATH); 1201} 1202 1203/* 1204 * Check the disk label information and retrieve needed vdev name-value pairs. 1205 * 1206 * Return: 1207 * 0 - success 1208 * ERR_* - failure 1209 */ 1210int 1211check_pool_label(uint64_t sector, char *stack, char *outdevid, 1212 char *outpath, uint64_t *outguid) 1213{ 1214 vdev_phys_t *vdev; 1215 uint64_t pool_state, txg = 0; 1216 char *nvlist, *nv; 1217 uint64_t diskguid; 1218 uint64_t version; 1219 1220 sector += (VDEV_SKIP_SIZE >> SPA_MINBLOCKSHIFT); 1221 1222 /* Read in the vdev name-value pair list (112K). */ 1223 if (devread(sector, 0, VDEV_PHYS_SIZE, stack) == 0) 1224 return (ERR_READ); 1225 1226 vdev = (vdev_phys_t *)stack; 1227 stack += sizeof (vdev_phys_t); 1228 1229 if (nvlist_unpack(vdev->vp_nvlist, &nvlist)) 1230 return (ERR_FSYS_CORRUPT); 1231 1232 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_STATE, &pool_state, 1233 DATA_TYPE_UINT64, NULL)) 1234 return (ERR_FSYS_CORRUPT); 1235 1236 if (pool_state == POOL_STATE_DESTROYED) 1237 return (ERR_FILESYSTEM_NOT_FOUND); 1238 1239 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_NAME, 1240 current_rootpool, DATA_TYPE_STRING, NULL)) 1241 return (ERR_FSYS_CORRUPT); 1242 1243 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_TXG, &txg, 1244 DATA_TYPE_UINT64, NULL)) 1245 return (ERR_FSYS_CORRUPT); 1246 1247 /* not an active device */ 1248 if (txg == 0) 1249 return (ERR_NO_BOOTPATH); 1250 1251 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_VERSION, &version, 1252 DATA_TYPE_UINT64, NULL)) 1253 return (ERR_FSYS_CORRUPT); 1254 if (version > SPA_VERSION) 1255 return (ERR_NEWER_VERSION); 1256 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_VDEV_TREE, &nv, 1257 DATA_TYPE_NVLIST, NULL)) 1258 return (ERR_FSYS_CORRUPT); 1259 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_GUID, &diskguid, 1260 DATA_TYPE_UINT64, NULL)) 1261 return (ERR_FSYS_CORRUPT); 1262 if (vdev_get_bootpath(nv, diskguid, outdevid, outpath, 0)) 1263 return (ERR_NO_BOOTPATH); 1264 if (nvlist_lookup_value(nvlist, ZPOOL_CONFIG_POOL_GUID, outguid, 1265 DATA_TYPE_UINT64, NULL)) 1266 return (ERR_FSYS_CORRUPT); 1267 return (0); 1268} 1269 1270/* 1271 * zfs_mount() locates a valid uberblock of the root pool and read in its MOS 1272 * to the memory address MOS. 1273 * 1274 * Return: 1275 * 1 - success 1276 * 0 - failure 1277 */ 1278int 1279zfs_mount(void) 1280{ 1281 char *stack; 1282 int label = 0; 1283 uberblock_phys_t *ub_array, *ubbest; 1284 objset_phys_t *osp; 1285 char tmp_bootpath[MAXNAMELEN]; 1286 char tmp_devid[MAXNAMELEN]; 1287 uint64_t tmp_guid; 1288 uint64_t adjpl = (uint64_t)part_length << SPA_MINBLOCKSHIFT; 1289 int err = errnum; /* preserve previous errnum state */ 1290 1291 /* if it's our first time here, zero the best uberblock out */ 1292 if (best_drive == 0 && best_part == 0 && find_best_root) { 1293 grub_memset(¤t_uberblock, 0, sizeof (uberblock_t)); 1294 pool_guid = 0; 1295 } 1296 1297 stackbase = ZFS_SCRATCH; 1298 stack = stackbase; 1299 ub_array = (uberblock_phys_t *)stack; 1300 stack += VDEV_UBERBLOCK_RING; 1301 1302 osp = (objset_phys_t *)stack; 1303 stack += sizeof (objset_phys_t); 1304 adjpl = P2ALIGN(adjpl, (uint64_t)sizeof (vdev_label_t)); 1305 1306 for (label = 0; label < VDEV_LABELS; label++) { 1307 1308 /* 1309 * some eltorito stacks don't give us a size and 1310 * we end up setting the size to MAXUINT, further 1311 * some of these devices stop working once a single 1312 * read past the end has been issued. Checking 1313 * for a maximum part_length and skipping the backup 1314 * labels at the end of the slice/partition/device 1315 * avoids breaking down on such devices. 1316 */ 1317 if (part_length == MAXUINT && label == 2) 1318 break; 1319 1320 uint64_t sector = vdev_label_start(adjpl, 1321 label) >> SPA_MINBLOCKSHIFT; 1322 1323 /* Read in the uberblock ring (128K). */ 1324 if (devread(sector + 1325 ((VDEV_SKIP_SIZE + VDEV_PHYS_SIZE) >> 1326 SPA_MINBLOCKSHIFT), 0, VDEV_UBERBLOCK_RING, 1327 (char *)ub_array) == 0) 1328 continue; 1329 1330 if ((ubbest = find_bestub(ub_array, sector)) != NULL && 1331 zio_read(&ubbest->ubp_uberblock.ub_rootbp, osp, stack) 1332 == 0) { 1333 1334 VERIFY_OS_TYPE(osp, DMU_OST_META); 1335 1336 if (check_pool_label(sector, stack, tmp_devid, 1337 tmp_bootpath, &tmp_guid)) 1338 continue; 1339 if (pool_guid == 0) 1340 pool_guid = tmp_guid; 1341 1342 if (find_best_root && ((pool_guid != tmp_guid) || 1343 vdev_uberblock_compare(&ubbest->ubp_uberblock, 1344 &(current_uberblock)) <= 0)) 1345 continue; 1346 1347 /* Got the MOS. Save it at the memory addr MOS. */ 1348 grub_memmove(MOS, &osp->os_meta_dnode, DNODE_SIZE); 1349 grub_memmove(¤t_uberblock, 1350 &ubbest->ubp_uberblock, sizeof (uberblock_t)); 1351 grub_memmove(current_bootpath, tmp_bootpath, 1352 MAXNAMELEN); 1353 grub_memmove(current_devid, tmp_devid, 1354 grub_strlen(tmp_devid)); 1355 is_zfs_mount = 1; 1356 return (1); 1357 } 1358 } 1359 1360 /* 1361 * While some fs impls. (tftp) rely on setting and keeping 1362 * global errnums set, others won't reset it and will break 1363 * when issuing rawreads. The goal here is to simply not 1364 * have zfs mount attempts impact the previous state. 1365 */ 1366 errnum = err; 1367 return (0); 1368} 1369 1370/* 1371 * zfs_open() locates a file in the rootpool by following the 1372 * MOS and places the dnode of the file in the memory address DNODE. 1373 * 1374 * Return: 1375 * 1 - success 1376 * 0 - failure 1377 */ 1378int 1379zfs_open(char *filename) 1380{ 1381 char *stack; 1382 dnode_phys_t *mdn; 1383 1384 file_buf = NULL; 1385 stackbase = ZFS_SCRATCH; 1386 stack = stackbase; 1387 1388 mdn = (dnode_phys_t *)stack; 1389 stack += sizeof (dnode_phys_t); 1390 1391 dnode_mdn = NULL; 1392 dnode_buf = (dnode_phys_t *)stack; 1393 stack += 1<<DNODE_BLOCK_SHIFT; 1394 1395 /* 1396 * menu.lst is placed at the root pool filesystem level, 1397 * do not goto 'current_bootfs'. 1398 */ 1399 if (is_top_dataset_file(filename)) { 1400 if (errnum = get_objset_mdn(MOS, NULL, NULL, mdn, stack)) 1401 return (0); 1402 1403 current_bootfs_obj = 0; 1404 } else { 1405 if (current_bootfs[0] == '\0') { 1406 /* Get the default root filesystem object number */ 1407 if (errnum = get_default_bootfsobj(MOS, 1408 ¤t_bootfs_obj, stack)) 1409 return (0); 1410 1411 if (errnum = get_objset_mdn(MOS, NULL, 1412 ¤t_bootfs_obj, mdn, stack)) 1413 return (0); 1414 } else { 1415 if (errnum = get_objset_mdn(MOS, current_bootfs, 1416 ¤t_bootfs_obj, mdn, stack)) { 1417 grub_memset(current_bootfs, 0, MAXNAMELEN); 1418 return (0); 1419 } 1420 } 1421 } 1422 1423 if (dnode_get_path(mdn, filename, DNODE, stack)) { 1424 errnum = ERR_FILE_NOT_FOUND; 1425 return (0); 1426 } 1427 1428 /* get the file size and set the file position to 0 */ 1429 1430 /* 1431 * For DMU_OT_SA we will need to locate the SIZE attribute 1432 * attribute, which could be either in the bonus buffer 1433 * or the "spill" block. 1434 */ 1435 if (DNODE->dn_bonustype == DMU_OT_SA) { 1436 sa_hdr_phys_t *sahdrp; 1437 int hdrsize; 1438 1439 if (DNODE->dn_bonuslen != 0) { 1440 sahdrp = (sa_hdr_phys_t *)DN_BONUS(DNODE); 1441 } else { 1442 if (DNODE->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 1443 blkptr_t *bp = &DNODE->dn_spill; 1444 void *buf; 1445 1446 buf = (void *)stack; 1447 stack += BP_GET_LSIZE(bp); 1448 1449 /* reset errnum to rawread() failure */ 1450 errnum = 0; 1451 if (zio_read(bp, buf, stack) != 0) { 1452 return (0); 1453 } 1454 sahdrp = buf; 1455 } else { 1456 errnum = ERR_FSYS_CORRUPT; 1457 return (0); 1458 } 1459 } 1460 hdrsize = SA_HDR_SIZE(sahdrp); 1461 filemax = *(uint64_t *)((char *)sahdrp + hdrsize + 1462 SA_SIZE_OFFSET); 1463 } else { 1464 filemax = ((znode_phys_t *)DN_BONUS(DNODE))->zp_size; 1465 } 1466 filepos = 0; 1467 1468 dnode_buf = NULL; 1469 return (1); 1470} 1471 1472/* 1473 * zfs_read reads in the data blocks pointed by the DNODE. 1474 * 1475 * Return: 1476 * len - the length successfully read in to the buffer 1477 * 0 - failure 1478 */ 1479int 1480zfs_read(char *buf, int len) 1481{ 1482 char *stack; 1483 char *tmpbuf; 1484 int blksz, length, movesize; 1485 1486 if (file_buf == NULL) { 1487 file_buf = stackbase; 1488 stackbase += SPA_MAXBLOCKSIZE; 1489 file_start = file_end = 0; 1490 } 1491 stack = stackbase; 1492 1493 /* 1494 * If offset is in memory, move it into the buffer provided and return. 1495 */ 1496 if (filepos >= file_start && filepos+len <= file_end) { 1497 grub_memmove(buf, file_buf + filepos - file_start, len); 1498 filepos += len; 1499 return (len); 1500 } 1501 1502 blksz = DNODE->dn_datablkszsec << SPA_MINBLOCKSHIFT; 1503 1504 /* 1505 * Entire Dnode is too big to fit into the space available. We 1506 * will need to read it in chunks. This could be optimized to 1507 * read in as large a chunk as there is space available, but for 1508 * now, this only reads in one data block at a time. 1509 */ 1510 length = len; 1511 while (length) { 1512 /* 1513 * Find requested blkid and the offset within that block. 1514 */ 1515 uint64_t blkid = filepos / blksz; 1516 1517 if (errnum = dmu_read(DNODE, blkid, file_buf, stack)) 1518 return (0); 1519 1520 file_start = blkid * blksz; 1521 file_end = file_start + blksz; 1522 1523 movesize = MIN(length, file_end - filepos); 1524 1525 grub_memmove(buf, file_buf + filepos - file_start, 1526 movesize); 1527 buf += movesize; 1528 length -= movesize; 1529 filepos += movesize; 1530 } 1531 1532 return (len); 1533} 1534 1535/* 1536 * No-Op 1537 */ 1538int 1539zfs_embed(int *start_sector, int needed_sectors) 1540{ 1541 return (1); 1542} 1543 1544#endif /* FSYS_ZFS */ 1545