1/* 2 * Copyright (c) 2010-2012 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29#include <stdio.h> 30#include <stddef.h> 31#include <stdlib.h> 32#include <string.h> 33#include <limits.h> 34#include <err.h> 35#include <errno.h> 36#include <fcntl.h> 37#include <unistd.h> 38#include <stdarg.h> 39#include <sys/types.h> 40#include <sys/param.h> 41#include <sys/stat.h> 42#include <sys/ioctl.h> 43#include <sys/disk.h> 44#include <sys/param.h> 45 46#include "../fsck_hfs.h" 47#include "fsck_journal.h" 48 49extern char debug; 50 51#include <hfs/hfs_format.h> 52#include <libkern/OSByteOrder.h> 53 54typedef struct SwapType { 55 const char *name; 56 uint16_t (^swap16)(uint16_t); 57 uint32_t (^swap32)(uint32_t); 58 uint64_t (^swap64)(uint64_t); 59} swapper_t; 60 61static swapper_t nativeEndian = { 62 "native endian", 63 ^(uint16_t x) { return x; }, 64 ^(uint32_t x) { return x; }, 65 ^(uint64_t x) { return x; } 66}; 67 68static swapper_t swappedEndian = { 69 "swapped endian", 70 ^(uint16_t x) { return OSSwapInt16(x); }, 71 ^(uint32_t x) { return OSSwapInt32(x); }, 72 ^(uint64_t x) { return OSSwapInt64(x); } 73}; 74 75typedef int (^journal_write_block_t)(off_t, void *, size_t); 76 77// 78// this isn't a great checksum routine but it will do for now. 79// we use it to checksum the journal header and the block list 80// headers that are at the start of each transaction. 81// 82static uint32_t 83calc_checksum(char *ptr, int len) 84{ 85 int i; 86 uint32_t cksum = 0; 87 88 // this is a lame checksum but for now it'll do 89 for(i = 0; i < len; i++, ptr++) { 90 cksum = (cksum << 8) ^ (cksum + *(unsigned char *)ptr); 91 } 92 93 return (~cksum); 94} 95 96typedef struct JournalIOInfo { 97 int jfd; // File descriptor for journal buffer 98 int wrapCount; // Incremented when it wraps around. 99 size_t bSize; // Block size. I/O needs to be done in that amount. 100 uint64_t base; // Base offset of journal buffer, past the header 101 uint64_t size; // Size of the journal, minus the header size 102 uint64_t end; // End of the journal (initially the "end" field from the journal header) 103 uint64_t current; // Current offset; starts at "start" 104} JournalIOInfo_t; 105 106/* 107 * Attempt to read <length> bytes from the journal buffer. 108 * Since this is a wrapped buffer, it may have to start at the 109 * beginning. info->{base, size, end} are read-only; info->current 110 * is updated with the current offset. It returns the number of bytes 111 * it read, or -1 on error. 112 */ 113static ssize_t 114journalRead(JournalIOInfo_t *info, uint8_t *buffer, size_t length) 115{ 116 size_t nread = 0; 117 uint8_t *ptr = buffer; 118 119// fprintf(stderr, "%s(%p, %p, %zu)\n", __FUNCTION__, info, buffer, length); 120 if (info->wrapCount > 1) { 121 fplog(stderr, "%s(%p, %p, %zu): journal buffer wrap count = %d\n", __FUNCTION__, info, buffer, length, info->wrapCount); 122 return -1; 123 } 124 while (nread < length) { 125 off_t end; 126 size_t amt; 127 ssize_t n; 128 129 if (info->end < info->current) { 130 // It wraps, so we max out at bse+size 131 end = info->base + info->size; 132 } else { 133 end = info->end; 134 } 135 amt = MIN((length - nread), (end - info->current)); 136 if (amt == 0) { 137 if (debug) { 138 fplog(stderr, "Journal read amount is 0, is that right?\n"); 139 } 140 goto done; 141 } 142 143 n = pread(info->jfd, ptr, amt, info->current); 144 if (n == -1) { 145 warn("pread(%d, %p, %zu, %llu)", info->jfd, ptr, amt, info->current); 146 goto done; 147 } 148 if (n != amt) { 149 if (debug) { 150 fplog(stderr, "%s(%d): Wanted to read %zu, but only read %zd\n", __FUNCTION__, __LINE__, amt, n); 151 } 152 } 153 nread += n; 154 ptr += n; 155 info->current += n; 156 if (info->current == (info->base + info->size)) { 157 info->current = info->base; 158 info->wrapCount++; 159 } 160 } 161done: 162 return nread; 163} 164 165/* 166 * Read a transaction from the journal buffer. 167 * A transaction is a list of block_list_headers, and their 168 * associated data. It needs to read all of the block_lists in 169 * a transaction, or it fails. It returns NULL if there are 170 * no transactions, and on error. (Maybe that should change?) 171 */ 172static block_list_header * 173getJournalTransaction(JournalIOInfo_t *jinfo, swapper_t *swap) 174{ 175 block_list_header *retval = NULL; 176 uint8_t block[jinfo->bSize]; 177 block_list_header *hdr = (void*)█ 178 ssize_t nread; 179 ssize_t amt; 180 181 memset(block, 0, sizeof(block)); 182 nread = journalRead(jinfo, block, sizeof(block)); 183 if (nread == -1 || 184 (size_t)nread != sizeof(block)) { 185 if (debug) 186 plog("%s: wanted %zd, got %zd\n", __FUNCTION__, sizeof(block), nread); 187 return NULL; 188 } 189 if (swap->swap32(hdr->num_blocks) == 0) { 190 /* 191 * Either there really are no blocks, or this is not a valid 192 * transaction. Either way, there's nothing for us to do here. 193 */ 194 if (debug) 195 fplog(stderr, "%s(%d): hdr->num_blocks == 0\n", __FUNCTION__, __LINE__); 196 return NULL; 197 } 198 /* 199 * Now we check the checksum to see if this is a valid header. 200 * Note that we verify the checksum before reading any more -- if 201 * it's not a valid header, we don't want to read more than a block 202 * size. 203 */ 204 uint32_t tmpChecksum = swap->swap32(hdr->checksum); 205 uint32_t compChecksum; 206 hdr->checksum = 0; 207 compChecksum = calc_checksum((void*)hdr, sizeof(*hdr)); 208 hdr->checksum = swap->swap32(tmpChecksum); 209 210 if (compChecksum != tmpChecksum) { 211 if (debug) 212 fplog(stderr, "%s(%d): hdr has bad checksum, returning NULL\n", __FUNCTION__, __LINE__); 213 return NULL; 214 } 215 216 if (swap->swap32(hdr->bytes_used) < sizeof(block)) { 217 if (debug) { 218 fplog(stderr, "%s(%d): hdr has bytes_used (%u) less than sizeof block (%zd)\n", 219 __FUNCTION__, __LINE__, swap->swap32(hdr->bytes_used), sizeof(block)); 220 } 221 return NULL; 222 } 223 224 retval = malloc(swap->swap32(hdr->bytes_used)); 225 if (retval == NULL) 226 return NULL; 227 228 memset(retval, 0, swap->swap32(hdr->bytes_used)); 229 memcpy(retval, block, sizeof(block)); 230 amt = swap->swap32(hdr->bytes_used) - sizeof(block); 231 nread = journalRead(jinfo, ((uint8_t*)retval) + sizeof(block), amt); 232 if (nread != amt) { 233 free(retval); 234 return NULL; 235 } 236 237 return retval; 238} 239 240/* 241 * Replay a transaction. 242 * Transactions have a blockListSize amount of block_list_header, and 243 * are then followed by data. We read it in, verify the checksum, and 244 * if it's good, we call the block that was passed in to do something 245 * with it. Maybe write it out. Maybe laugh about it. 246 * 247 * It returns -1 if there was an error before it wrote anything out, 248 * and -2 if there was an error after it wrote something out. 249 * 250 * The arguments are: 251 * txn -- a block_list_header pointer, which has the description and data 252 * to be replayed. 253 * blSize -- the size of the block_list for this journal. (The data 254 * are after the block_list, but part of the same buffer.) 255 * blkSize -- The block size used to convert block numbers to offsets. This 256 * is defined to be the size of the journal header. 257 * swap -- A pointer to a swapper_t used to swap journal data structure elements. 258 * writer -- A block-of-code that does writing. 259 * 260 * "writer" should return -1 to stop the replay (this propagates an error up). 261 */ 262static int 263replayTransaction(block_list_header *txn, size_t blSize, size_t blkSize, swapper_t *swap, journal_write_block_t writer) 264{ 265 uint32_t i; 266 uint8_t *endPtr = ((uint8_t*)txn) + swap->swap32(txn->bytes_used); 267 uint8_t *dataPtr = ((uint8_t*)txn) + blSize; 268 int retval = -1; 269 for (i = 1; i < swap->swap32(txn->num_blocks); i++) { 270 if (debug) 271 plog("\tBlock %d: blkNum %llu, size %u, data offset = %zd\n", i, swap->swap64(txn->binfo[i].bnum), swap->swap32(txn->binfo[i].bsize), dataPtr - (uint8_t*)txn); 272 /* 273 * XXX 274 * Check with security types on these checks. Need to ensure 275 * that the fields don't take us off into the dark scary woods. 276 * It's mostly the second one that I am unsure about. 277 */ 278 if (dataPtr > endPtr) { 279 if (debug) 280 plog("\tData out of range for block_list_header\n"); 281 return retval; 282 } 283 if ((endPtr - dataPtr) < swap->swap32(txn->binfo[i].bsize)) { 284 if (debug) 285 plog("\tData size for block %d out of range for block_list_header\n", i); 286 return retval; 287 } 288 if ((dataPtr + swap->swap32(txn->binfo[i].bsize)) > endPtr) { 289 if (debug) 290 plog("\tData end out of range for block_list_header\n"); 291 return retval; 292 } 293 // Just for debugging 294 if (debug) { 295 if (swap->swap64(txn->binfo[i].bnum) == 2) { 296 HFSPlusVolumeHeader *vp = (void*)dataPtr; 297 plog("vp->signature = %#x, version = %#x\n", vp->signature, vp->version); 298 } 299 } 300 // It's in the spec, and I saw it come up once on a live volume. 301 if (swap->swap64(txn->binfo[i].bnum) == ~(uint64_t)0) { 302 if (debug) 303 plog("\tSkipping this block due to magic skip number\n"); 304 } else { 305 // Should we set retval to -2 here? 306 if (writer) { 307 if ((writer)(swap->swap64(txn->binfo[i].bnum) * blkSize, dataPtr, swap->swap32(txn->binfo[i].bsize)) == -1) 308 return retval; 309 } 310 } 311 dataPtr += swap->swap32(txn->binfo[i].bsize); 312 retval = -2; 313 } 314 return 0; 315} 316 317/* 318 * Read a journal header in from the journal device. 319 */ 320static int 321loadJournalHeader(int jfd, off_t offset, size_t blockSize, journal_header *jhp) 322{ 323 uint8_t buffer[blockSize]; 324 ssize_t nread; 325 326 nread = pread(jfd, buffer, sizeof(buffer), offset); 327 if (nread == -1 || 328 (size_t)nread != sizeof(buffer)) { 329 warn("tried to read %zu for journal header buffer, got %zd", sizeof(buffer), nread); 330 return -1; 331 } 332 *jhp = *(journal_header*)buffer; 333 return 0; 334} 335 336/* 337 * Replay a journal (called "journal_open" because you have to 338 * to replay it as part of opening it). At this point, all it 339 * is useful for is replaying the journal. 340 * 341 * It is passed in: 342 * jfd -- file descriptor for the journal device 343 * offset -- offset (in bytes) of the journal on the journal device 344 * journal_size -- size of the jorunal (in bytes) 345 * min_fs_blksize -- Blocksize of the data filesystem 346 * flags -- unused for now 347 * jdev_name -- string name for the journal device. used for logging. 348 * do_write_b -- a block which does the actual writing. 349 * 350 * Currently, for fsck_hfs, the do_write_b block writes to the cache. It could also 351 * just print out the block numbers, or just check their integrity, as much as is 352 * possible. 353 * 354 * The function works by loading the journal header. From there, it then starts 355 * loading transactions, via block_list_header groups. When it gets to the end 356 * of the journal, it tries continuing, in case there were transactions that 357 * didn't get updated in the header (this apparently happens). 358 * 359 * It returns 0 on success, and -1 on error. Note that there's not a lot 360 * fsck_hfs can probably do in the event of error. 361 * 362 */ 363int 364journal_open(int jfd, 365 off_t offset, // Offset of journal 366 off_t journal_size, // Size, in bytes, of the entire journal 367 size_t min_fs_blksize, // Blocksize of the data filesystem, journal blocksize must be at least this size 368 uint32_t flags __unused, // Not used in this implementation 369 const char *jdev_name, // The name of the journal device, for logging 370 int (^do_write_b)(off_t, void*, size_t)) 371{ 372 journal_header jhdr = { 0 }; 373 swapper_t *jnlSwap; // Used to swap fields of the journal 374 uint32_t tempCksum; // Temporary checksum value 375 uint32_t jBlkSize = 0; 376 377 if (ioctl(jfd, DKIOCGETBLOCKSIZE, &jBlkSize) == -1) { 378 jBlkSize = min_fs_blksize; 379 } else { 380 if (jBlkSize < min_fs_blksize) { 381 fplog(stderr, "%s: journal block size %u < min block size %zu for %s\n", __FUNCTION__, jBlkSize, min_fs_blksize, jdev_name); 382 return -1; 383 } 384 if ((jBlkSize % min_fs_blksize) != 0) { 385 fplog(stderr, "%s: journal block size %u is not a multiple of fs block size %zu for %s\n", __FUNCTION__, jBlkSize, min_fs_blksize, jdev_name); 386 return -1; 387 } 388 } 389 if (loadJournalHeader(jfd, offset, jBlkSize, &jhdr) != 0) { 390 fplog(stderr, "%s: unable to load journal header from %s\n", __FUNCTION__, jdev_name); 391 return -1; 392 } 393 394 /* 395 * Unlike the rest of the filesystem, the journal can be in native or 396 * non-native byte order. Barring moving a filesystem from one host 397 * to another, it'll almost always be in native byte order. 398 */ 399 if (jhdr.endian == ENDIAN_MAGIC) { 400 jnlSwap = &nativeEndian; 401 } else if (OSSwapInt32(jhdr.endian) == ENDIAN_MAGIC) { 402 jnlSwap = &swappedEndian; 403 } else { 404 fplog(stderr, "%s: Unknown journal endian magic number %#x from %s\n", __FUNCTION__, jhdr.endian, jdev_name); 405 return -1; 406 } 407 /* 408 * Two different magic numbers are valid. 409 * Do they mean different thigs, though? 410 */ 411 if (jnlSwap->swap32(jhdr.magic) != JOURNAL_HEADER_MAGIC && 412 jnlSwap->swap32(jhdr.magic) != OLD_JOURNAL_HEADER_MAGIC) { 413 fplog(stderr, "%s: Unknown journal header magic number %#x from %s\n", __FUNCTION__, jhdr.magic, jdev_name); 414 return -1; 415 } 416 417 /* 418 * Checksums have to be done with the checksum field set to 0. 419 * So we have to stash it aside for a bit, and set the field to 420 * 0, before we can compare. Afterwards, if it compares correctly, 421 * we put the original (swapped, if necessary) value back, just 422 * in case. 423 */ 424 tempCksum = jnlSwap->swap32(jhdr.checksum); 425 jhdr.checksum = 0; 426 if (jnlSwap->swap32(jhdr.magic) == JOURNAL_HEADER_MAGIC && 427 (calc_checksum((void*)&jhdr, JOURNAL_HEADER_CKSUM_SIZE) != tempCksum)) { 428 fplog(stderr, "%s: Invalid journal checksum from %s\n", __FUNCTION__, jdev_name); 429 return -1; 430 } 431 jhdr.checksum = jnlSwap->swap32(tempCksum); 432 433 /* 434 * Set up information about the journal which we use to do the I/O. 435 * The journal is a circular buffer. However, the start of the journal 436 * buffer is past the journal header. See the JournalIOInfo structure above. 437 */ 438 off_t startOffset = jnlSwap->swap64(jhdr.start); 439 off_t endOffset =jnlSwap->swap64(jhdr.end); 440 off_t journalStart = offset + jnlSwap->swap32(jhdr.jhdr_size); 441 442 /* 443 * The journal code was updated to be able to read past the "end" of the journal, 444 * to see if there were any valid transactions there. If we are peeking past the 445 * end, we don't care if we have checksum errors -- that just means they're not 446 * valid transactions. 447 * 448 */ 449 int into_the_weeds = 0; 450 uint32_t last_sequence_number = 0; 451 452 JournalIOInfo_t jinfo = { 0 }; 453 454 if (debug) 455 plog("Journal start sequence number = %u\n", jnlSwap->swap32(jhdr.sequence_num)); 456 457 /* 458 * Now set up the JournalIOInfo object with the file descriptor, 459 * the block size, start and end of the journal buffer, and where 460 * the journal pointer currently is. 461 */ 462 jinfo.jfd = jfd; 463 jinfo.bSize = jnlSwap->swap32(jhdr.jhdr_size); 464 jinfo.base = journalStart; 465 jinfo.size = journal_size - jinfo.bSize; 466 jinfo.end = offset + endOffset; 467 jinfo.current = offset + startOffset; 468 469 const char *state = ""; 470 int bad_journal = 0; 471 block_list_header *txn = NULL; 472 473 /* 474 * Loop while getting transactions. We exit when we hit a checksum 475 * error, or when the sequence number for a transaction doesn't match 476 * what we expect it to. (That's the trickiest part -- the into_the_weeds 477 * portion of the code. It doesn't match the TN11150 documentation, so 478 * I've had to go by both my experience with real-world journals and by 479 * looking at the kernel code.) 480 */ 481 while (1) { 482 int rv; 483 484 if (jinfo.current == jinfo.end && into_the_weeds == 0) { 485 /* 486 * This is a bit weird, but it works: if current == end, but gone_into_weeds is 1, 487 * then this code will not execute. If it does execute, it'll go to get a transaction. 488 * That will put the pointer past end. 489 */ 490 if (jhdr.sequence_num == 0) { 491 /* 492 * XXX 493 * I am not sure about this; this behaviour is not in TN1150 at all, 494 * but I _think_ this is what the kernel is doing. 495 */ 496 plog("Journal sequence number is 0, is going into the end okay?\n"); 497 } 498 into_the_weeds = 1; 499 if (debug) 500 plog("Attempting to read past stated end of journal\n"); 501 state = "tentative "; 502 jinfo.end = (jinfo.base + startOffset - jinfo.bSize); 503 continue; 504 } 505 if (debug) 506 plog("Before getting %stransaction: jinfo.current = %llu\n", state, jinfo.current); 507 /* 508 * Note that getJournalTransaction verifies the checksum on the block_list_header, so 509 * if it's bad, it'll return NULL. 510 */ 511 txn = getJournalTransaction(&jinfo, jnlSwap); 512 if (txn == NULL) { 513 if (debug) 514 plog("txn is NULL, jinfo.current = %llu\n", jinfo.current); 515 if (into_the_weeds) { 516 if (debug) 517 plog("\tBut we do not care, since it is past the end of the journal\n"); 518 } else { 519 bad_journal = 1; 520 } 521 break; 522 } 523 if (debug) { 524 plog("After getting %stransaction: jinfo.current = %llu\n", state, jinfo.current); 525 plog("%stxn = { %u max_blocks, %u num_blocks, %u bytes_used, binfo[0].next = %u }\n", state, jnlSwap->swap32(txn->max_blocks), jnlSwap->swap32(txn->num_blocks), jnlSwap->swap32(txn->bytes_used), jnlSwap->swap32(txn->binfo[0].next)); 526 } 527 if (into_the_weeds) { 528 /* 529 * This seems to be what the kernel was checking: if the 530 * last_sequence_number was set, and the txn sequence number 531 * is set, and the txn sequence number doesn't match either 532 * last_sequence_number _or_ an incremented version of it, then 533 * the transaction isn't worth looking at, and we've reached 534 * the end of the journal. 535 */ 536 if (last_sequence_number != 0 && 537 txn->binfo[0].next != 0 && 538 jnlSwap->swap32(txn->binfo[0].next) != last_sequence_number && 539 jnlSwap->swap32(txn->binfo[0].next) != (last_sequence_number + 1)) { 540 // Probably not a valid transaction 541 if (debug) 542 plog("\tTentative txn sequence %u is not expected %u, stopping journal replay\n", jnlSwap->swap32(txn->binfo[0].next), last_sequence_number + 1); 543 break; 544 } 545 } 546 /* 547 * If we've got a valid transaction, then we replay it. 548 * If there was an error, we're done with the journal replay. 549 * (If the error occurred after the "end," then we don't care, 550 * and it's not a bad journal.) 551 */ 552 rv = replayTransaction(txn, 553 jnlSwap->swap32(jhdr.blhdr_size), 554 jnlSwap->swap32(jhdr.jhdr_size), 555 jnlSwap, 556 do_write_b); 557 558 if (rv < 0) { 559 if (debug) 560 plog("\tTransaction replay failed, returned %d\n", rv); 561 if (into_the_weeds) { 562 if (debug) 563 plog("\t\tAnd we don't care\n"); 564 } else { 565 bad_journal = 1; 566 } 567 break; 568 } 569 last_sequence_number = jnlSwap->swap32(txn->binfo[0].next); 570 free(txn); 571 txn = NULL; 572 } 573 if (txn) 574 free(txn); 575 if (bad_journal) { 576 if (debug) 577 plog("Journal was bad, stopped replaying\n"); 578 return -1; 579 } 580 581 return 0; 582} 583