sbin/fsck_msdosfs/fat.c

29 __RCSID("$NetBSD: fat.c,v 1.12 2000/10/10 20:24:52 is Exp $");
132 checkclnum(struct bootblock *boot, u_int fat, cl_t cl, cl_t *next)
147 		      cl, fat,
200 	struct fatEntry *fat;
211 	fat = malloc(len = boot->NumClusters * sizeof(struct fatEntry));
212 	if (fat == NULL) {
217 	(void)memset(fat, 0, len);
282 			fat[cl].next = p[0] + (p[1] << 8)
284 			fat[cl].next &= boot->ClustMask;
285 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
290 			fat[cl].next = p[0] + (p[1] << 8);
291 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
296 			fat[cl].next = (p[0] + (p[1] << 8)) & 0x0fff;
297 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
301 			fat[cl].next = ((p[1] >> 4) + (p[2] << 4)) & 0x0fff;
302 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
311 		free(fat);
314 		*fp = fat;
417 clearchain(struct bootblock *boot, struct fatEntry *fat, cl_t head)
422 		if (fat[p].head != head)
424 		q = fat[p].next;
425 		fat[p].next = fat[p].head = CLUST_FREE;
426 		fat[p].length = 0;
431 tryclear(struct bootblock *boot, struct fatEntry *fat, cl_t head, cl_t *trunc)
434 		clearchain(boot, fat, head);
447 checkfat(struct bootblock *boot, struct fatEntry *fat)
459 		if (fat[head].head != 0		/* cluster already belongs to some chain */
460 		    || fat[head].next == CLUST_FREE
461 		    || fat[head].next == CLUST_BAD)
467 		     p = fat[p].next) {
468 			fat[p].head = head;
473 		fat[head].length = fat[head].next == CLUST_FREE ? 0 : len;
483 		if (fat[head].head != head)
488 		     (n = fat[p].next) >= CLUST_FIRST && n < boot->NumClusters;
490 			if (fat[n].head != head)
498 			ret |= tryclear(boot, fat, head, &fat[p].next);
504 			ret |= tryclear(boot, fat, head, &fat[p].next);
508 		      head, fat[n].head, n);
509 		conf = tryclear(boot, fat, head, &fat[p].next);
510 		if (ask(0, "Clear chain starting at %u", h = fat[n].head)) {
517 				     p = fat[p].next) {
518 					if (h != fat[p].head) {
525 					fat[p].head = head;
528 			clearchain(boot, fat, h);
541 writefat(int fs, struct bootblock *boot, struct fatEntry *fat, int correct_fat)
605 			if (fat[cl].next == CLUST_FREE)
607 			*p++ = (u_char)fat[cl].next;
608 			*p++ = (u_char)(fat[cl].next >> 8);
609 			*p++ = (u_char)(fat[cl].next >> 16);
611 			*p++ |= (fat[cl].next >> 24)&0x0f;
614 			if (fat[cl].next == CLUST_FREE)
616 			*p++ = (u_char)fat[cl].next;
617 			*p++ = (u_char)(fat[cl].next >> 8);
620 			if (fat[cl].next == CLUST_FREE)
623 			    && fat[cl + 1].next == CLUST_FREE)
625 			*p++ = (u_char)fat[cl].next;
626 			*p++ = (u_char)((fat[cl].next >> 8) & 0xf)
627 			       |(u_char)(fat[cl+1].next << 4);
628 			*p++ = (u_char)(fat[++cl].next >> 4);
649 checklost(int dosfs, struct bootblock *boot, struct fatEntry *fat)
657 		if (fat[head].head != head
658 		    || fat[head].next == CLUST_FREE
659 		    || (fat[head].next >= CLUST_RSRVD
660 			&& fat[head].next < CLUST_EOFS)
661 		    || (fat[head].flags & FAT_USED))
665 		      head, fat[head].length);
666 		mod |= ret = reconnect(dosfs, boot, fat, head);
670 			clearchain(boot, fat, head);