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 |
} |