sbin/fsck_msdosfs/fat.c

29 __RCSID("$NetBSD: fat.c,v 1.18 2006/06/05 16:51:18 christos Exp $");
31   "$FreeBSD: releng/11.0/sbin/fsck_msdosfs/fat.c 268632 2014-07-14 20:58:02Z pfg $";
133 checkclnum(struct bootblock *boot, u_int fat, cl_t cl, cl_t *next)
148 		      cl, fat,
202 	struct fatEntry *fat;
213 	fat = malloc(len = boot->NumClusters * sizeof(struct fatEntry));
214 	if (fat == NULL) {
219 	(void)memset(fat, 0, len);
284 			fat[cl].next = p[0] + (p[1] << 8)
286 			fat[cl].next &= boot->ClustMask;
287 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
292 			fat[cl].next = p[0] + (p[1] << 8);
293 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
298 			fat[cl].next = (p[0] + (p[1] << 8)) & 0x0fff;
299 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
303 			fat[cl].next = ((p[1] >> 4) + (p[2] << 4)) & 0x0fff;
304 			ret |= checkclnum(boot, no, cl, &fat[cl].next);
313 		free(fat);
316 		*fp = fat;
419 clearchain(struct bootblock *boot, struct fatEntry *fat, cl_t head)
424 		if (fat[p].head != head)
426 		q = fat[p].next;
427 		fat[p].next = fat[p].head = CLUST_FREE;
428 		fat[p].length = 0;
433 tryclear(struct bootblock *boot, struct fatEntry *fat, cl_t head, cl_t *truncp)
436 		clearchain(boot, fat, head);
444 		    p = fat[p].next, len++)
447 		fat[head].length = len;
457 checkfat(struct bootblock *boot, struct fatEntry *fat)
469 		if (fat[head].head != 0		/* cluster already belongs to some chain */
470 		    || fat[head].next == CLUST_FREE
471 		    || fat[head].next == CLUST_BAD)
477 		     fat[p].head != head;
478 		     p = fat[p].next) {
479 			fat[p].head = head;
484 		fat[head].length = fat[head].next == CLUST_FREE ? 0 : len;
494 		if (fat[head].head != head)
498 		for (len = fat[head].length, p = head;
499 		     (n = fat[p].next) >= CLUST_FIRST && n < boot->NumClusters;
501 			if (fat[n].head != head || len-- < 2)
510 			ret |= tryclear(boot, fat, head, &fat[p].next);
518 		if (head == fat[n].head) {
525 		      head, fat[n].head, n);
526 		conf = tryclear(boot, fat, head, &fat[p].next);
527 		if (ask(0, "Clear chain starting at %u", h = fat[n].head)) {
534 				     p = fat[p].next) {
535 					if (h != fat[p].head) {
542 					fat[p].head = head;
545 			clearchain(boot, fat, h);
558 writefat(int fs, struct bootblock *boot, struct fatEntry *fat, int correct_fat)
622 			if (fat[cl].next == CLUST_FREE)
624 			*p++ = (u_char)fat[cl].next;
625 			*p++ = (u_char)(fat[cl].next >> 8);
626 			*p++ = (u_char)(fat[cl].next >> 16);
628 			*p++ |= (fat[cl].next >> 24)&0x0f;
631 			if (fat[cl].next == CLUST_FREE)
633 			*p++ = (u_char)fat[cl].next;
634 			*p++ = (u_char)(fat[cl].next >> 8);
637 			if (fat[cl].next == CLUST_FREE)
639 			*p++ = (u_char)fat[cl].next;
640 			*p = (u_char)((fat[cl].next >> 8) & 0xf);
644 			if (fat[cl].next == CLUST_FREE)
646 			*p++ |= (u_char)(fat[cl + 1].next << 4);
647 			*p++ = (u_char)(fat[cl + 1].next >> 4);
668 checklost(int dosfs, struct bootblock *boot, struct fatEntry *fat)
676 		if (fat[head].head != head
677 		    || fat[head].next == CLUST_FREE
678 		    || (fat[head].next >= CLUST_RSRVD
679 			&& fat[head].next < CLUST_EOFS)
680 		    || (fat[head].flags & FAT_USED))
684 		      head, fat[head].length);
685 		mod |= ret = reconnect(dosfs, boot, fat, head);
689 			clearchain(boot, fat, head);