| 1 |
/* |
| 2 |
* libhfs - library for reading and writing Macintosh HFS volumes |
| 3 |
* Copyright (C) 1996-1998 Robert Leslie |
| 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 |
|
| 21 |
# ifdef HAVE_CONFIG_H |
| 22 |
# include "config.h" |
| 23 |
# endif |
| 24 |
|
| 25 |
# include <stdlib.h> |
| 26 |
# include <string.h> |
| 27 |
# include <errno.h> |
| 28 |
|
| 29 |
# include "libhfs.h" |
| 30 |
# include "volume.h" |
| 31 |
# include "block.h" |
| 32 |
# include "os.h" |
| 33 |
|
| 34 |
# define INUSE(b) ((b)->flags & HFS_BUCKET_INUSE) |
| 35 |
# define DIRTY(b) ((b)->flags & HFS_BUCKET_DIRTY) |
| 36 |
|
| 37 |
/* |
| 38 |
* NAME: block->init() |
| 39 |
* DESCRIPTION: initialize a volume's block cache |
| 40 |
*/ |
| 41 |
int b_init(hfsvol *vol) |
| 42 |
{ |
| 43 |
bcache *cache; |
| 44 |
int i; |
| 45 |
|
| 46 |
ASSERT(vol->cache == 0); |
| 47 |
|
| 48 |
cache = ALLOC(bcache, 1); |
| 49 |
if (cache == 0) |
| 50 |
ERROR(ENOMEM, 0); |
| 51 |
|
| 52 |
vol->cache = cache; |
| 53 |
|
| 54 |
cache->vol = vol; |
| 55 |
cache->tail = &cache->chain[HFS_CACHESZ - 1]; |
| 56 |
|
| 57 |
cache->hits = 0; |
| 58 |
cache->misses = 0; |
| 59 |
|
| 60 |
for (i = 0; i < HFS_CACHESZ; ++i) |
| 61 |
{ |
| 62 |
bucket *b = &cache->chain[i]; |
| 63 |
|
| 64 |
b->flags = 0; |
| 65 |
b->count = 0; |
| 66 |
|
| 67 |
b->bnum = 0; |
| 68 |
b->data = &cache->pool[i]; |
| 69 |
|
| 70 |
b->cnext = b + 1; |
| 71 |
b->cprev = b - 1; |
| 72 |
|
| 73 |
b->hnext = 0; |
| 74 |
b->hprev = 0; |
| 75 |
} |
| 76 |
|
| 77 |
cache->chain[0].cprev = cache->tail; |
| 78 |
cache->tail->cnext = &cache->chain[0]; |
| 79 |
|
| 80 |
for (i = 0; i < HFS_HASHSZ; ++i) |
| 81 |
cache->hash[i] = 0; |
| 82 |
|
| 83 |
return 0; |
| 84 |
|
| 85 |
fail: |
| 86 |
return -1; |
| 87 |
} |
| 88 |
|
| 89 |
# ifdef DEBUG |
| 90 |
/* |
| 91 |
* NAME: block->showstats() |
| 92 |
* DESCRIPTION: output cache hit/miss ratio |
| 93 |
*/ |
| 94 |
void b_showstats(const bcache *cache) |
| 95 |
{ |
| 96 |
// fprintf(stderr, "BLOCK: CACHE vol 0x%lx \"%s\" hit/miss ratio = %.3f\n", |
| 97 |
(unsigned long) cache->vol, cache->vol->mdb.drVN, |
| 98 |
(float) cache->hits / (float) cache->misses); |
| 99 |
} |
| 100 |
|
| 101 |
/* |
| 102 |
* NAME: block->dumpcache() |
| 103 |
* DESCRIPTION: dump the cache tables for a volume |
| 104 |
*/ |
| 105 |
/*void b_dumpcache(const bcache *cache) |
| 106 |
{ |
| 107 |
const bucket *b; |
| 108 |
int i; |
| 109 |
|
| 110 |
fprintf(stderr, "BLOCK CACHE DUMP:\n"); |
| 111 |
|
| 112 |
for (i = 0, b = cache->tail->cnext; i < HFS_CACHESZ; ++i, b = b->cnext) |
| 113 |
{ |
| 114 |
if (INUSE(b)) |
| 115 |
{ |
| 116 |
fprintf(stderr, "\t %lu", b->bnum); |
| 117 |
if (DIRTY(b)) |
| 118 |
fprintf(stderr, "*"); |
| 119 |
|
| 120 |
fprintf(stderr, ":%u", b->count); |
| 121 |
} |
| 122 |
} |
| 123 |
|
| 124 |
fprintf(stderr, "\n"); |
| 125 |
|
| 126 |
fprintf(stderr, "BLOCK HASH DUMP:\n"); |
| 127 |
|
| 128 |
for (i = 0; i < HFS_HASHSZ; ++i) |
| 129 |
{ |
| 130 |
int seen = 0; |
| 131 |
|
| 132 |
for (b = cache->hash[i]; b; b = b->hnext) |
| 133 |
{ |
| 134 |
if (! seen) |
| 135 |
fprintf(stderr, " %d:", i); |
| 136 |
|
| 137 |
if (INUSE(b)) |
| 138 |
{ |
| 139 |
fprintf(stderr, " %lu", b->bnum); |
| 140 |
if (DIRTY(b)) |
| 141 |
fprintf(stderr, "*"); |
| 142 |
|
| 143 |
fprintf(stderr, ":%u", b->count); |
| 144 |
} |
| 145 |
|
| 146 |
seen = 1; |
| 147 |
} |
| 148 |
|
| 149 |
if (seen) |
| 150 |
fprintf(stderr, "\n"); |
| 151 |
} |
| 152 |
}*/ |
| 153 |
# endif |
| 154 |
|
| 155 |
/* |
| 156 |
* NAME: fillchain() |
| 157 |
* DESCRIPTION: fill a chain of bucket buffers with a single read |
| 158 |
*/ |
| 159 |
static |
| 160 |
int fillchain(hfsvol *vol, bucket **bptr, unsigned int *count) |
| 161 |
{ |
| 162 |
bucket *blist[HFS_BLOCKBUFSZ], **start = bptr; |
| 163 |
unsigned long bnum; |
| 164 |
unsigned int len, i; |
| 165 |
|
| 166 |
for (len = 0; len < HFS_BLOCKBUFSZ && |
| 167 |
(unsigned int) (bptr - start) < *count; ++bptr) |
| 168 |
{ |
| 169 |
if (INUSE(*bptr)) |
| 170 |
continue; |
| 171 |
|
| 172 |
if (len > 0 && (*bptr)->bnum != bnum) |
| 173 |
break; |
| 174 |
|
| 175 |
blist[len++] = *bptr; |
| 176 |
bnum = (*bptr)->bnum + 1; |
| 177 |
} |
| 178 |
|
| 179 |
*count = bptr - start; |
| 180 |
|
| 181 |
if (len == 0) |
| 182 |
goto done; |
| 183 |
else if (len == 1) |
| 184 |
{ |
| 185 |
if (b_readpb(vol, vol->vstart + blist[0]->bnum, |
| 186 |
blist[0]->data, 1) == -1) |
| 187 |
goto fail; |
| 188 |
} |
| 189 |
else |
| 190 |
{ |
| 191 |
block buffer[HFS_BLOCKBUFSZ]; |
| 192 |
|
| 193 |
if (b_readpb(vol, vol->vstart + blist[0]->bnum, buffer, len) == -1) |
| 194 |
goto fail; |
| 195 |
|
| 196 |
for (i = 0; i < len; ++i) |
| 197 |
memcpy(blist[i]->data, buffer[i], HFS_BLOCKSZ); |
| 198 |
} |
| 199 |
|
| 200 |
for (i = 0; i < len; ++i) |
| 201 |
{ |
| 202 |
blist[i]->flags |= HFS_BUCKET_INUSE; |
| 203 |
blist[i]->flags &= ~HFS_BUCKET_DIRTY; |
| 204 |
} |
| 205 |
|
| 206 |
done: |
| 207 |
return 0; |
| 208 |
|
| 209 |
fail: |
| 210 |
return -1; |
| 211 |
} |
| 212 |
|
| 213 |
/* |
| 214 |
* NAME: flushchain() |
| 215 |
* DESCRIPTION: store a chain of bucket buffers with a single write |
| 216 |
*/ |
| 217 |
static |
| 218 |
int flushchain(hfsvol *vol, bucket **bptr, unsigned int *count) |
| 219 |
{ |
| 220 |
bucket *blist[HFS_BLOCKBUFSZ], **start = bptr; |
| 221 |
unsigned long bnum; |
| 222 |
unsigned int len, i; |
| 223 |
|
| 224 |
for (len = 0; len < HFS_BLOCKBUFSZ && |
| 225 |
(unsigned int) (bptr - start) < *count; ++bptr) |
| 226 |
{ |
| 227 |
if (! INUSE(*bptr) || ! DIRTY(*bptr)) |
| 228 |
continue; |
| 229 |
|
| 230 |
if (len > 0 && (*bptr)->bnum != bnum) |
| 231 |
break; |
| 232 |
|
| 233 |
blist[len++] = *bptr; |
| 234 |
bnum = (*bptr)->bnum + 1; |
| 235 |
} |
| 236 |
|
| 237 |
*count = bptr - start; |
| 238 |
|
| 239 |
if (len == 0) |
| 240 |
goto done; |
| 241 |
else if (len == 1) |
| 242 |
{ |
| 243 |
if (b_writepb(vol, vol->vstart + blist[0]->bnum, |
| 244 |
(const block*)blist[0]->data, 1) == -1) |
| 245 |
goto fail; |
| 246 |
} |
| 247 |
else |
| 248 |
{ |
| 249 |
block buffer[HFS_BLOCKBUFSZ]; |
| 250 |
|
| 251 |
for (i = 0; i < len; ++i) |
| 252 |
memcpy(buffer[i], blist[i]->data, HFS_BLOCKSZ); |
| 253 |
|
| 254 |
if (b_writepb(vol, vol->vstart + blist[0]->bnum, (const block*)buffer, len) == -1) |
| 255 |
goto fail; |
| 256 |
} |
| 257 |
|
| 258 |
for (i = 0; i < len; ++i) |
| 259 |
blist[i]->flags &= ~HFS_BUCKET_DIRTY; |
| 260 |
|
| 261 |
done: |
| 262 |
return 0; |
| 263 |
|
| 264 |
fail: |
| 265 |
return -1; |
| 266 |
} |
| 267 |
|
| 268 |
/* |
| 269 |
* NAME: compare() |
| 270 |
* DESCRIPTION: comparison function for qsort of cache bucket pointers |
| 271 |
*/ |
| 272 |
static |
| 273 |
int compare(const bucket **b1, const bucket **b2) |
| 274 |
{ |
| 275 |
long diff; |
| 276 |
|
| 277 |
diff = (*b1)->bnum - (*b2)->bnum; |
| 278 |
|
| 279 |
if (diff < 0) |
| 280 |
return -1; |
| 281 |
else if (diff > 0) |
| 282 |
return 1; |
| 283 |
else |
| 284 |
return 0; |
| 285 |
} |
| 286 |
|
| 287 |
/* |
| 288 |
* NAME: dobuckets() |
| 289 |
* DESCRIPTION: fill or flush an array of cache buckets to a volume |
| 290 |
*/ |
| 291 |
static |
| 292 |
int dobuckets(hfsvol *vol, bucket **chain, unsigned int len, |
| 293 |
int (*func)(hfsvol *, bucket **, unsigned int *)) |
| 294 |
{ |
| 295 |
unsigned int count, i; |
| 296 |
int result = 0; |
| 297 |
|
| 298 |
qsort(chain, len, sizeof(*chain), |
| 299 |
(int (*)(const void *, const void *)) compare); |
| 300 |
|
| 301 |
for (i = 0; i < len; i += count) |
| 302 |
{ |
| 303 |
count = len - i; |
| 304 |
if (func(vol, chain + i, &count) == -1) |
| 305 |
result = -1; |
| 306 |
} |
| 307 |
|
| 308 |
return result; |
| 309 |
} |
| 310 |
|
| 311 |
# define fillbuckets(vol, chain, len) dobuckets(vol, chain, len, fillchain) |
| 312 |
# define flushbuckets(vol, chain, len) dobuckets(vol, chain, len, flushchain) |
| 313 |
|
| 314 |
/* |
| 315 |
* NAME: block->flush() |
| 316 |
* DESCRIPTION: commit dirty cache blocks to a volume |
| 317 |
*/ |
| 318 |
int b_flush(hfsvol *vol) |
| 319 |
{ |
| 320 |
bcache *cache = vol->cache; |
| 321 |
bucket *chain[HFS_CACHESZ]; |
| 322 |
int i; |
| 323 |
|
| 324 |
if (cache == 0 || (vol->flags & HFS_VOL_READONLY)) |
| 325 |
goto done; |
| 326 |
|
| 327 |
for (i = 0; i < HFS_CACHESZ; ++i) |
| 328 |
chain[i] = &cache->chain[i]; |
| 329 |
|
| 330 |
if (flushbuckets(vol, chain, HFS_CACHESZ) == -1) |
| 331 |
goto fail; |
| 332 |
|
| 333 |
done: |
| 334 |
# ifdef DEBUG |
| 335 |
if (cache) |
| 336 |
b_showstats(cache); |
| 337 |
# endif |
| 338 |
|
| 339 |
return 0; |
| 340 |
|
| 341 |
fail: |
| 342 |
return -1; |
| 343 |
} |
| 344 |
|
| 345 |
/* |
| 346 |
* NAME: block->finish() |
| 347 |
* DESCRIPTION: commit and free a volume's block cache |
| 348 |
*/ |
| 349 |
int b_finish(hfsvol *vol) |
| 350 |
{ |
| 351 |
int result = 0; |
| 352 |
|
| 353 |
if (vol->cache == 0) |
| 354 |
goto done; |
| 355 |
|
| 356 |
# ifdef DEBUG |
| 357 |
b_dumpcache(vol->cache); |
| 358 |
# endif |
| 359 |
|
| 360 |
result = b_flush(vol); |
| 361 |
|
| 362 |
FREE(vol->cache); |
| 363 |
vol->cache = 0; |
| 364 |
|
| 365 |
done: |
| 366 |
return result; |
| 367 |
} |
| 368 |
|
| 369 |
/* |
| 370 |
* NAME: findbucket() |
| 371 |
* DESCRIPTION: locate a bucket in the cache, and/or its hash slot |
| 372 |
*/ |
| 373 |
static |
| 374 |
bucket *findbucket(bcache *cache, unsigned long bnum, bucket ***hslot) |
| 375 |
{ |
| 376 |
bucket *b; |
| 377 |
|
| 378 |
*hslot = &cache->hash[bnum & (HFS_HASHSZ - 1)]; |
| 379 |
|
| 380 |
for (b = **hslot; b; b = b->hnext) |
| 381 |
{ |
| 382 |
if (INUSE(b) && b->bnum == bnum) |
| 383 |
break; |
| 384 |
} |
| 385 |
|
| 386 |
return b; |
| 387 |
} |
| 388 |
|
| 389 |
/* |
| 390 |
* NAME: reuse() |
| 391 |
* DESCRIPTION: free a bucket for reuse, flushing if necessary |
| 392 |
*/ |
| 393 |
static |
| 394 |
int reuse(bcache *cache, bucket *b, unsigned long bnum) |
| 395 |
{ |
| 396 |
bucket *chain[HFS_BLOCKBUFSZ], *bptr; |
| 397 |
int i; |
| 398 |
|
| 399 |
# ifdef DEBUG |
| 400 |
if (INUSE(b)) |
| 401 |
printf(stderr, "BLOCK: CACHE reusing bucket containing " |
| 402 |
"vol 0x%lx block %lu:%u\n", |
| 403 |
(unsigned long) cache->vol, b->bnum, b->count); |
| 404 |
# endif |
| 405 |
|
| 406 |
if (INUSE(b) && DIRTY(b)) |
| 407 |
{ |
| 408 |
/* flush most recently unused buckets */ |
| 409 |
|
| 410 |
for (bptr = b, i = 0; i < HFS_BLOCKBUFSZ; ++i) |
| 411 |
{ |
| 412 |
chain[i] = bptr; |
| 413 |
bptr = bptr->cprev; |
| 414 |
} |
| 415 |
|
| 416 |
if (flushbuckets(cache->vol, chain, HFS_BLOCKBUFSZ) == -1) |
| 417 |
goto fail; |
| 418 |
} |
| 419 |
|
| 420 |
b->flags &= ~HFS_BUCKET_INUSE; |
| 421 |
b->count = 1; |
| 422 |
b->bnum = bnum; |
| 423 |
|
| 424 |
return 0; |
| 425 |
|
| 426 |
fail: |
| 427 |
return -1; |
| 428 |
} |
| 429 |
|
| 430 |
/* |
| 431 |
* NAME: cplace() |
| 432 |
* DESCRIPTION: move a bucket to an appropriate place near head of the chain |
| 433 |
*/ |
| 434 |
static |
| 435 |
void cplace(bcache *cache, bucket *b) |
| 436 |
{ |
| 437 |
bucket *p; |
| 438 |
|
| 439 |
for (p = cache->tail->cnext; p->count > 1; p = p->cnext) |
| 440 |
--p->count; |
| 441 |
|
| 442 |
b->cnext->cprev = b->cprev; |
| 443 |
b->cprev->cnext = b->cnext; |
| 444 |
|
| 445 |
if (cache->tail == b) |
| 446 |
cache->tail = b->cprev; |
| 447 |
|
| 448 |
b->cprev = p->cprev; |
| 449 |
b->cnext = p; |
| 450 |
|
| 451 |
p->cprev->cnext = b; |
| 452 |
p->cprev = b; |
| 453 |
} |
| 454 |
|
| 455 |
/* |
| 456 |
* NAME: hplace() |
| 457 |
* DESCRIPTION: move a bucket to the head of its hash slot |
| 458 |
*/ |
| 459 |
static |
| 460 |
void hplace(bucket **hslot, bucket *b) |
| 461 |
{ |
| 462 |
if (*hslot != b) |
| 463 |
{ |
| 464 |
if (b->hprev) |
| 465 |
*b->hprev = b->hnext; |
| 466 |
if (b->hnext) |
| 467 |
b->hnext->hprev = b->hprev; |
| 468 |
|
| 469 |
b->hprev = hslot; |
| 470 |
b->hnext = *hslot; |
| 471 |
|
| 472 |
if (*hslot) |
| 473 |
(*hslot)->hprev = &b->hnext; |
| 474 |
|
| 475 |
*hslot = b; |
| 476 |
} |
| 477 |
} |
| 478 |
|
| 479 |
/* |
| 480 |
* NAME: getbucket() |
| 481 |
* DESCRIPTION: fetch a bucket from the cache, or an empty one to be filled |
| 482 |
*/ |
| 483 |
static |
| 484 |
bucket *getbucket(bcache *cache, unsigned long bnum, int fill) |
| 485 |
{ |
| 486 |
bucket **hslot, *b, *p, *bptr, |
| 487 |
*chain[HFS_BLOCKBUFSZ], **slots[HFS_BLOCKBUFSZ]; |
| 488 |
|
| 489 |
b = findbucket(cache, bnum, &hslot); |
| 490 |
|
| 491 |
if (b) |
| 492 |
{ |
| 493 |
/* cache hit; move towards head of cache chain */ |
| 494 |
|
| 495 |
++cache->hits; |
| 496 |
|
| 497 |
if (++b->count > b->cprev->count && |
| 498 |
b != cache->tail->cnext) |
| 499 |
{ |
| 500 |
p = b->cprev; |
| 501 |
|
| 502 |
p->cprev->cnext = b; |
| 503 |
b->cnext->cprev = p; |
| 504 |
|
| 505 |
p->cnext = b->cnext; |
| 506 |
b->cprev = p->cprev; |
| 507 |
|
| 508 |
p->cprev = b; |
| 509 |
b->cnext = p; |
| 510 |
|
| 511 |
if (cache->tail == b) |
| 512 |
cache->tail = p; |
| 513 |
} |
| 514 |
} |
| 515 |
else |
| 516 |
{ |
| 517 |
/* cache miss; reuse least-used cache bucket */ |
| 518 |
|
| 519 |
++cache->misses; |
| 520 |
|
| 521 |
b = cache->tail; |
| 522 |
|
| 523 |
if (reuse(cache, b, bnum) == -1) |
| 524 |
goto fail; |
| 525 |
|
| 526 |
if (fill) |
| 527 |
{ |
| 528 |
unsigned int len = 0; |
| 529 |
|
| 530 |
chain[len] = b; |
| 531 |
slots[len++] = hslot; |
| 532 |
|
| 533 |
for (bptr = b->cprev; |
| 534 |
len < (HFS_BLOCKBUFSZ >> 1) && ++bnum < cache->vol->vlen; |
| 535 |
bptr = bptr->cprev) |
| 536 |
{ |
| 537 |
if (findbucket(cache, bnum, &hslot)) |
| 538 |
break; |
| 539 |
|
| 540 |
if (reuse(cache, bptr, bnum) == -1) |
| 541 |
goto fail; |
| 542 |
|
| 543 |
chain[len] = bptr; |
| 544 |
slots[len++] = hslot; |
| 545 |
} |
| 546 |
|
| 547 |
if (fillbuckets(cache->vol, chain, len) == -1) |
| 548 |
goto fail; |
| 549 |
|
| 550 |
while (--len) |
| 551 |
{ |
| 552 |
cplace(cache, chain[len]); |
| 553 |
hplace(slots[len], chain[len]); |
| 554 |
} |
| 555 |
|
| 556 |
hslot = slots[0]; |
| 557 |
} |
| 558 |
|
| 559 |
/* move bucket to appropriate place in chain */ |
| 560 |
|
| 561 |
cplace(cache, b); |
| 562 |
} |
| 563 |
|
| 564 |
/* insert at front of hash chain */ |
| 565 |
|
| 566 |
hplace(hslot, b); |
| 567 |
|
| 568 |
return b; |
| 569 |
|
| 570 |
fail: |
| 571 |
return 0; |
| 572 |
} |
| 573 |
|
| 574 |
/* |
| 575 |
* NAME: block->readpb() |
| 576 |
* DESCRIPTION: read blocks from the physical medium (bypassing cache) |
| 577 |
*/ |
| 578 |
int b_readpb(hfsvol *vol, unsigned long bnum, block *bp, unsigned int blen) |
| 579 |
{ |
| 580 |
unsigned long nblocks; |
| 581 |
|
| 582 |
# ifdef DEBUG |
| 583 |
fprintf(stderr, "BLOCK: READ vol 0x%lx block %lu", |
| 584 |
(unsigned long) vol, bnum); |
| 585 |
if (blen > 1) |
| 586 |
fprintf(stderr, "+%u[..%lu]\n", blen - 1, bnum + blen - 1); |
| 587 |
else |
| 588 |
fprintf(stderr, "\n"); |
| 589 |
# endif |
| 590 |
|
| 591 |
nblocks = hfs_os_seek(&vol->priv, bnum); |
| 592 |
if (nblocks == (unsigned long) -1) |
| 593 |
goto fail; |
| 594 |
|
| 595 |
if (nblocks != bnum) |
| 596 |
ERROR(EIO, "block seek failed for read"); |
| 597 |
|
| 598 |
nblocks = hfs_os_read(&vol->priv, bp, blen); |
| 599 |
if (nblocks == (unsigned long) -1) |
| 600 |
goto fail; |
| 601 |
|
| 602 |
if (nblocks != blen) |
| 603 |
ERROR(EIO, "incomplete block read"); |
| 604 |
|
| 605 |
return 0; |
| 606 |
|
| 607 |
fail: |
| 608 |
return -1; |
| 609 |
} |
| 610 |
|
| 611 |
/* |
| 612 |
* NAME: block->writepb() |
| 613 |
* DESCRIPTION: write blocks to the physical medium (bypassing cache) |
| 614 |
*/ |
| 615 |
int b_writepb(hfsvol *vol, unsigned long bnum, const block *bp, |
| 616 |
unsigned int blen) |
| 617 |
{ |
| 618 |
unsigned long nblocks; |
| 619 |
|
| 620 |
# ifdef DEBUG |
| 621 |
fprintf(stderr, "BLOCK: WRITE vol 0x%lx block %lu", |
| 622 |
(unsigned long) vol, bnum); |
| 623 |
if (blen > 1) |
| 624 |
fprintf(stderr, "+%u[..%lu]\n", blen - 1, bnum + blen - 1); |
| 625 |
else |
| 626 |
fprintf(stderr, "\n"); |
| 627 |
# endif |
| 628 |
|
| 629 |
nblocks = hfs_os_seek(&vol->priv, bnum); |
| 630 |
if (nblocks == (unsigned long) -1) |
| 631 |
goto fail; |
| 632 |
|
| 633 |
if (nblocks != bnum) |
| 634 |
ERROR(EIO, "block seek failed for write"); |
| 635 |
|
| 636 |
nblocks = hfs_os_write(&vol->priv, bp, blen); |
| 637 |
if (nblocks == (unsigned long) -1) |
| 638 |
goto fail; |
| 639 |
|
| 640 |
if (nblocks != blen) |
| 641 |
ERROR(EIO, "incomplete block write"); |
| 642 |
|
| 643 |
return 0; |
| 644 |
|
| 645 |
fail: |
| 646 |
return -1; |
| 647 |
} |
| 648 |
|
| 649 |
/* |
| 650 |
* NAME: block->readlb() |
| 651 |
* DESCRIPTION: read a logical block from a volume (or from the cache) |
| 652 |
*/ |
| 653 |
int b_readlb(hfsvol *vol, unsigned long bnum, block *bp) |
| 654 |
{ |
| 655 |
if (vol->vlen > 0 && bnum >= vol->vlen) |
| 656 |
ERROR(EIO, "read nonexistent logical block"); |
| 657 |
|
| 658 |
if (vol->cache) |
| 659 |
{ |
| 660 |
bucket *b; |
| 661 |
|
| 662 |
b = getbucket(vol->cache, bnum, 1); |
| 663 |
if (b == 0) |
| 664 |
goto fail; |
| 665 |
|
| 666 |
memcpy(bp, b->data, HFS_BLOCKSZ); |
| 667 |
} |
| 668 |
else |
| 669 |
{ |
| 670 |
if (b_readpb(vol, vol->vstart + bnum, bp, 1) == -1) |
| 671 |
goto fail; |
| 672 |
} |
| 673 |
|
| 674 |
return 0; |
| 675 |
|
| 676 |
fail: |
| 677 |
return -1; |
| 678 |
} |
| 679 |
|
| 680 |
/* |
| 681 |
* NAME: block->writelb() |
| 682 |
* DESCRIPTION: write a logical block to a volume (or to the cache) |
| 683 |
*/ |
| 684 |
int b_writelb(hfsvol *vol, unsigned long bnum, const block *bp) |
| 685 |
{ |
| 686 |
if (vol->vlen > 0 && bnum >= vol->vlen) |
| 687 |
ERROR(EIO, "write nonexistent logical block"); |
| 688 |
|
| 689 |
if (vol->cache) |
| 690 |
{ |
| 691 |
bucket *b; |
| 692 |
|
| 693 |
b = getbucket(vol->cache, bnum, 0); |
| 694 |
if (b == 0) |
| 695 |
goto fail; |
| 696 |
|
| 697 |
if (! INUSE(b) || |
| 698 |
memcmp(b->data, bp, HFS_BLOCKSZ) != 0) |
| 699 |
{ |
| 700 |
memcpy(b->data, bp, HFS_BLOCKSZ); |
| 701 |
b->flags |= HFS_BUCKET_INUSE | HFS_BUCKET_DIRTY; |
| 702 |
} |
| 703 |
} |
| 704 |
else |
| 705 |
{ |
| 706 |
if (b_writepb(vol, vol->vstart + bnum, bp, 1) == -1) |
| 707 |
goto fail; |
| 708 |
} |
| 709 |
|
| 710 |
return 0; |
| 711 |
|
| 712 |
fail: |
| 713 |
return -1; |
| 714 |
} |
| 715 |
|
| 716 |
/* |
| 717 |
* NAME: block->readab() |
| 718 |
* DESCRIPTION: read a block from an allocation block from a volume |
| 719 |
*/ |
| 720 |
int b_readab(hfsvol *vol, unsigned int anum, unsigned int index, block *bp) |
| 721 |
{ |
| 722 |
/* verify the allocation block exists and is marked as in-use */ |
| 723 |
|
| 724 |
if (anum >= vol->mdb.drNmAlBlks) |
| 725 |
ERROR(EIO, "read nonexistent allocation block"); |
| 726 |
else if (vol->vbm && ! BMTST(vol->vbm, anum)) |
| 727 |
ERROR(EIO, "read unallocated block"); |
| 728 |
|
| 729 |
return b_readlb(vol, vol->mdb.drAlBlSt + anum * vol->lpa + index, bp); |
| 730 |
|
| 731 |
fail: |
| 732 |
return -1; |
| 733 |
} |
| 734 |
|
| 735 |
/* |
| 736 |
* NAME: block->writeab() |
| 737 |
* DESCRIPTION: write a block to an allocation block to a volume |
| 738 |
*/ |
| 739 |
int b_writeab(hfsvol *vol, |
| 740 |
unsigned int anum, unsigned int index, const block *bp) |
| 741 |
{ |
| 742 |
/* verify the allocation block exists and is marked as in-use */ |
| 743 |
|
| 744 |
if (anum >= vol->mdb.drNmAlBlks) |
| 745 |
ERROR(EIO, "write nonexistent allocation block"); |
| 746 |
else if (vol->vbm && ! BMTST(vol->vbm, anum)) |
| 747 |
ERROR(EIO, "write unallocated block"); |
| 748 |
|
| 749 |
if (v_dirty(vol) == -1) |
| 750 |
goto fail; |
| 751 |
|
| 752 |
return b_writelb(vol, vol->mdb.drAlBlSt + anum * vol->lpa + index, bp); |
| 753 |
|
| 754 |
fail: |
| 755 |
return -1; |
| 756 |
} |
| 757 |
|
| 758 |
/* |
| 759 |
* NAME: block->size() |
| 760 |
* DESCRIPTION: return the number of physical blocks on a volume's medium |
| 761 |
*/ |
| 762 |
unsigned long b_size(hfsvol *vol) |
| 763 |
{ |
| 764 |
unsigned long low, high, mid; |
| 765 |
block b; |
| 766 |
|
| 767 |
high = hfs_os_seek(&vol->priv, -1); |
| 768 |
|
| 769 |
if (high != (unsigned long) -1 && high > 0) |
| 770 |
return high; |
| 771 |
|
| 772 |
/* manual size detection: first check there is at least 1 block in medium */ |
| 773 |
|
| 774 |
if (b_readpb(vol, 0, &b, 1) == -1) |
| 775 |
ERROR(EIO, "size of medium indeterminable or empty"); |
| 776 |
|
| 777 |
for (low = 0, high = 2880; |
| 778 |
high > 0 && b_readpb(vol, high - 1, &b, 1) != -1; |
| 779 |
high <<= 1) |
| 780 |
low = high - 1; |
| 781 |
|
| 782 |
if (high == 0) |
| 783 |
ERROR(EIO, "size of medium indeterminable or too large"); |
| 784 |
|
| 785 |
/* common case: 1440K floppy */ |
| 786 |
|
| 787 |
if (low == 2879 && b_readpb(vol, 2880, &b, 1) == -1) |
| 788 |
return 2880; |
| 789 |
|
| 790 |
/* binary search for other sizes */ |
| 791 |
|
| 792 |
while (low < high - 1) |
| 793 |
{ |
| 794 |
mid = (low + high) >> 1; |
| 795 |
|
| 796 |
if (b_readpb(vol, mid, &b, 1) == -1) |
| 797 |
high = mid; |
| 798 |
else |
| 799 |
low = mid; |
| 800 |
} |
| 801 |
|
| 802 |
return low + 1; |
| 803 |
|
| 804 |
fail: |
| 805 |
return 0; |
| 806 |
} |
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