xref: /openbsd-src/sbin/fsck_msdos/dir.c (revision 50b7afb2c2c0993b0894d4e34bf857cb13ed9c80)
1 /*	$OpenBSD: dir.c,v 1.26 2014/07/11 14:35:19 tobias Exp $	*/
2 /*	$NetBSD: dir.c,v 1.11 1997/10/17 11:19:35 ws Exp $	*/
3 
4 /*
5  * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
6  * Copyright (c) 1995 Martin Husemann
7  * Some structure declaration borrowed from Paul Popelka
8  * (paulp@uts.amdahl.com), see /sys/msdosfs/ for reference.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <ctype.h>
35 #include <stdio.h>
36 #include <unistd.h>
37 #include <time.h>
38 
39 #include <sys/param.h>
40 
41 #include "ext.h"
42 
43 #define	SLOT_EMPTY	0x00		/* slot has never been used */
44 #define	SLOT_E5		0x05		/* the real value is 0xe5 */
45 #define	SLOT_DELETED	0xe5		/* file in this slot deleted */
46 
47 #define	ATTR_NORMAL	0x00		/* normal file */
48 #define	ATTR_READONLY	0x01		/* file is readonly */
49 #define	ATTR_HIDDEN	0x02		/* file is hidden */
50 #define	ATTR_SYSTEM	0x04		/* file is a system file */
51 #define	ATTR_VOLUME	0x08		/* entry is a volume label */
52 #define	ATTR_DIRECTORY	0x10		/* entry is a directory name */
53 #define	ATTR_ARCHIVE	0x20		/* file is new or modified */
54 
55 #define	ATTR_WIN95	0x0f		/* long name record */
56 
57 /*
58  * This is the format of the contents of the deTime field in the direntry
59  * structure.
60  * We don't use bitfields because we don't know how compilers for
61  * arbitrary machines will lay them out.
62  */
63 #define DT_2SECONDS_MASK	0x1F	/* seconds divided by 2 */
64 #define DT_2SECONDS_SHIFT	0
65 #define DT_MINUTES_MASK		0x7E0	/* minutes */
66 #define DT_MINUTES_SHIFT	5
67 #define DT_HOURS_MASK		0xF800	/* hours */
68 #define DT_HOURS_SHIFT		11
69 
70 /*
71  * This is the format of the contents of the deDate field in the direntry
72  * structure.
73  */
74 #define DD_DAY_MASK		0x1F	/* day of month */
75 #define DD_DAY_SHIFT		0
76 #define DD_MONTH_MASK		0x1E0	/* month */
77 #define DD_MONTH_SHIFT		5
78 #define DD_YEAR_MASK		0xFE00	/* year - 1980 */
79 #define DD_YEAR_SHIFT		9
80 
81 /* dir.c */
82 static struct dosDirEntry *newDosDirEntry(void);
83 static void freeDosDirEntry(struct dosDirEntry *);
84 static struct dirTodoNode *newDirTodo(void);
85 static void freeDirTodo(struct dirTodoNode *);
86 static char *fullpath(struct dosDirEntry *);
87 static u_char calcShortSum(u_char *);
88 static int delete(int, struct bootblock *, struct fatEntry *, cl_t, int,
89     cl_t, int, int);
90 static int removede(int, struct bootblock *, struct fatEntry *, u_char *,
91     u_char *, cl_t, cl_t, cl_t, char *, int);
92 static int checksize(struct bootblock *, struct fatEntry *, u_char *,
93     struct dosDirEntry *);
94 static int readDosDirSection(int, struct bootblock *, struct fatEntry *,
95     struct dosDirEntry *);
96 
97 /*
98  * Manage free dosDirEntry structures.
99  */
100 static struct dosDirEntry *freede;
101 
102 static struct dosDirEntry *
103 newDosDirEntry(void)
104 {
105 	struct dosDirEntry *de;
106 
107 	if (!(de = freede)) {
108 		if (!(de = (struct dosDirEntry *)malloc(sizeof *de)))
109 			return (0);
110 	} else
111 		freede = de->next;
112 	return (de);
113 }
114 
115 static void
116 freeDosDirEntry(struct dosDirEntry *de)
117 {
118 	de->next = freede;
119 	freede = de;
120 }
121 
122 /*
123  * The same for dirTodoNode structures.
124  */
125 static struct dirTodoNode *freedt;
126 
127 static struct dirTodoNode *
128 newDirTodo(void)
129 {
130 	struct dirTodoNode *dt;
131 
132 	if (!(dt = freedt)) {
133 		if (!(dt = (struct dirTodoNode *)malloc(sizeof *dt)))
134 			return (0);
135 	} else
136 		freedt = dt->next;
137 	return (dt);
138 }
139 
140 static void
141 freeDirTodo(struct dirTodoNode *dt)
142 {
143 	dt->next = freedt;
144 	freedt = dt;
145 }
146 
147 /*
148  * The stack of unread directories
149  */
150 static struct dirTodoNode *pendingDirectories = NULL;
151 
152 /*
153  * Return the full pathname for a directory entry.
154  */
155 static char *
156 fullpath(struct dosDirEntry *dir)
157 {
158 	static char namebuf[MAXPATHLEN + 1];
159 	char *cp, *np;
160 	int nl;
161 
162 	cp = namebuf + sizeof namebuf;
163 	*--cp = '\0';
164 	for(;;) {
165 		np = dir->lname[0] ? dir->lname : dir->name;
166 		nl = strlen(np);
167 			/* cf dosDirEntry, sizeof(lname) < MAXPATHLEN, so test is safe */
168 		if (cp <= namebuf + 1 + nl) {
169 			*--cp = '?';
170 			break;
171 		}
172 		cp -= nl;
173 		(void)memcpy(cp, np, nl);
174 		dir = dir->parent;
175 		if (!dir)
176 			break;
177 		*--cp = '/';
178 	}
179 	return (cp);
180 }
181 
182 /*
183  * Calculate a checksum over an 8.3 alias name
184  */
185 static u_char
186 calcShortSum(u_char *p)
187 {
188 	u_char sum = 0;
189 	int i;
190 
191 	for (i = 0; i < 11; i++) {
192 		sum = (sum << 7)|(sum >> 1);	/* rotate right */
193 		sum += p[i];
194 	}
195 
196 	return (sum);
197 }
198 
199 /*
200  * Global variables temporarily used during a directory scan
201  */
202 static char longName[DOSLONGNAMELEN] = "";
203 static u_char *buffer = NULL;
204 static u_char *delbuf = NULL;
205 
206 static struct dosDirEntry *rootDir;
207 static struct dosDirEntry *lostDir;
208 
209 /*
210  * Init internal state for a new directory scan.
211  */
212 int
213 resetDosDirSection(struct bootblock *boot, struct fatEntry *fat)
214 {
215 	int b1, b2;
216 	int ret = FSOK;
217 
218 	b1 = boot->RootDirEnts * 32;
219 	b2 = boot->SecPerClust * boot->BytesPerSec;
220 
221 	if (!(buffer = malloc(b1 > b2 ? b1 : b2))
222 	    || !(delbuf = malloc(b2))
223 	    || !(rootDir = newDosDirEntry())) {
224 		xperror("No space for directory");
225 		goto fail;
226 	}
227 	(void)memset(rootDir, 0, sizeof *rootDir);
228 	if (boot->flags & FAT32) {
229 		if (boot->RootCl < CLUST_FIRST || boot->RootCl >= boot->NumClusters) {
230 			pfatal("Root directory starts with cluster out of range(%u)\n",
231 			       boot->RootCl);
232 			goto fail;
233 		}
234 		if (fat[boot->RootCl].head != boot->RootCl) {
235 			pfatal("Root directory doesn't start a cluster chain\n");
236 			goto fail;
237 		}
238 
239 		fat[boot->RootCl].flags |= FAT_USED;
240 		rootDir->head = boot->RootCl;
241 	}
242 
243 	return (ret);
244 fail:
245 	finishDosDirSection();
246 	return (FSFATAL);
247 }
248 
249 /*
250  * Cleanup after a directory scan
251  */
252 void
253 finishDosDirSection(void)
254 {
255 	struct dirTodoNode *p, *np;
256 	struct dosDirEntry *d, *nd;
257 
258 	for (p = pendingDirectories; p; p = np) {
259 		np = p->next;
260 		freeDirTodo(p);
261 	}
262 	pendingDirectories = 0;
263 	for (d = rootDir; d; d = nd) {
264 		if ((nd = d->child) != NULL) {
265 			d->child = 0;
266 			continue;
267 		}
268 		if (!(nd = d->next))
269 			nd = d->parent;
270 		freeDosDirEntry(d);
271 	}
272 	rootDir = lostDir = NULL;
273 	free(buffer);
274 	free(delbuf);
275 	buffer = NULL;
276 	delbuf = NULL;
277 }
278 
279 /*
280  * Delete directory entries between startcl, startoff and endcl, endoff.
281  */
282 static int
283 delete(int f, struct bootblock *boot, struct fatEntry *fat, cl_t startcl,
284        int startoff, cl_t endcl, int endoff, int notlast)
285 {
286 	u_char *s, *e;
287 	off_t off;
288 	int clsz = boot->SecPerClust * boot->BytesPerSec;
289 
290 	s = delbuf + startoff;
291 	e = delbuf + clsz;
292 	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
293 		if (startcl == endcl) {
294 			if (notlast)
295 				break;
296 			e = delbuf + endoff;
297 		}
298 		off = startcl * boot->SecPerClust + boot->ClusterOffset;
299 		off *= boot->BytesPerSec;
300 		if (lseek(f, off, SEEK_SET) != off
301 		    || read(f, delbuf, clsz) != clsz) {
302 			xperror("Unable to read directory");
303 			return (FSFATAL);
304 		}
305 		while (s < e) {
306 			*s = SLOT_DELETED;
307 			s += 32;
308 		}
309 		if (lseek(f, off, SEEK_SET) != off
310 		    || write(f, delbuf, clsz) != clsz) {
311 			xperror("Unable to write directory");
312 			return (FSFATAL);
313 		}
314 		if (startcl == endcl)
315 			break;
316 		startcl = fat[startcl].next;
317 		s = delbuf;
318 	}
319 	return (FSOK);
320 }
321 
322 static int
323 removede(int f, struct bootblock *boot, struct fatEntry *fat, u_char *start,
324 	 u_char *end, cl_t startcl, cl_t endcl, cl_t curcl, char *path, int type)
325 {
326 	switch (type) {
327 	case 0:
328 		pwarn("Invalid long filename entry for %s\n", path);
329 		break;
330 	case 1:
331 		pwarn("Invalid long filename entry at end of directory %s\n", path);
332 		break;
333 	case 2:
334 		pwarn("Invalid long filename entry for volume label\n");
335 		break;
336 	}
337 	if (ask(0, "Remove")) {
338 		if (startcl != curcl) {
339 			if (delete(f, boot, fat,
340 				   startcl, start - buffer,
341 				   endcl, end - buffer,
342 				   endcl == curcl) == FSFATAL)
343 				return (FSFATAL);
344 			start = buffer;
345 		}
346 		if (endcl == curcl)
347 			for (; start < end; start += 32)
348 				*start = SLOT_DELETED;
349 		return (FSDIRMOD);
350 	}
351 	return (FSERROR);
352 }
353 
354 /*
355  * Check an in-memory file entry
356  */
357 static int
358 checksize(struct bootblock *boot, struct fatEntry *fat, u_char *p,
359 	  struct dosDirEntry *dir)
360 {
361 	/*
362 	 * Check size on ordinary files
363 	 */
364 	u_int32_t physicalSize;
365 
366 	if (dir->head == CLUST_FREE)
367 		physicalSize = 0;
368 	else {
369 		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
370 			return (FSERROR);
371 		physicalSize = fat[dir->head].length * boot->ClusterSize;
372 	}
373 	if (physicalSize < dir->size) {
374 		pwarn("size of %s is %u, should at most be %u\n",
375 		      fullpath(dir), dir->size, physicalSize);
376 		if (ask(1, "Truncate")) {
377 			dir->size = physicalSize;
378 			p[28] = (u_char)physicalSize;
379 			p[29] = (u_char)(physicalSize >> 8);
380 			p[30] = (u_char)(physicalSize >> 16);
381 			p[31] = (u_char)(physicalSize >> 24);
382 			return (FSDIRMOD);
383 		} else
384 			return (FSERROR);
385 	} else if (physicalSize - dir->size >= boot->ClusterSize) {
386 		pwarn("%s has too many clusters allocated\n",
387 		      fullpath(dir));
388 		if (ask(1, "Drop superfluous clusters")) {
389 			cl_t cl;
390 			u_int32_t len, sz;
391 
392 			len = sz = 0;
393 			for (cl = dir->head; (sz += boot->ClusterSize) < dir->size;) {
394 				cl = fat[cl].next;
395 				len++;
396 			}
397 			clearchain(boot, fat, fat[cl].next);
398 			fat[cl].next = CLUST_EOF;
399 			fat[dir->head].length = len;
400 			return (FSFATMOD);
401 		} else
402 			return (FSERROR);
403 	}
404 	return (FSOK);
405 }
406 
407 /*
408  * Read a directory and
409  *   - resolve long name records
410  *   - enter file and directory records into the parent's list
411  *   - push directories onto the todo-stack
412  */
413 static int
414 readDosDirSection(int f, struct bootblock *boot, struct fatEntry *fat,
415 		  struct dosDirEntry *dir)
416 {
417 	struct dosDirEntry dirent, *d;
418 	u_char *p, *vallfn, *invlfn, *empty;
419 	off_t off;
420 	int i, j, k, last;
421 	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
422 	char *t;
423 	u_int lidx = 0;
424 	int shortSum;
425 	int mod = FSOK;
426 #define	THISMOD	0x8000			/* Only used within this routine */
427 
428 	cl = dir->head;
429 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
430 		/*
431 		 * Already handled somewhere else.
432 		 */
433 		return (FSOK);
434 	}
435 	shortSum = -1;
436 	vallfn = invlfn = empty = NULL;
437 	do {
438 		if (!(boot->flags & FAT32) && !dir->parent) {
439 			last = boot->RootDirEnts * 32;
440 			off = boot->ResSectors + boot->FATs * boot->FATsecs;
441 		} else {
442 			last = boot->SecPerClust * boot->BytesPerSec;
443 			off = cl * boot->SecPerClust + boot->ClusterOffset;
444 		}
445 
446 		off *= boot->BytesPerSec;
447 		if (lseek(f, off, SEEK_SET) != off
448 		    || read(f, buffer, last) != last) {
449 			xperror("Unable to read directory");
450 			return (FSFATAL);
451 		}
452 		last /= 32;
453 		/*
454 		 * Check `.' and `..' entries here?			XXX
455 		 */
456 		for (p = buffer, i = 0; i < last; i++, p += 32) {
457 			if (dir->fsckflags & DIREMPWARN) {
458 				*p = SLOT_EMPTY;
459 				continue;
460 			}
461 
462 			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
463 				if (*p == SLOT_EMPTY) {
464 					dir->fsckflags |= DIREMPTY;
465 					empty = p;
466 					empcl = cl;
467 				}
468 				continue;
469 			}
470 
471 			if (dir->fsckflags & DIREMPTY) {
472 				if (!(dir->fsckflags & DIREMPWARN)) {
473 					pwarn("%s has entries after end of directory\n",
474 					      fullpath(dir));
475 					if (ask(1, "Extend")) {
476 						u_char *q;
477 
478 						dir->fsckflags &= ~DIREMPTY;
479 						if (delete(f, boot, fat,
480 							   empcl, empty - buffer,
481 							   cl, p - buffer, 1) == FSFATAL)
482 							return (FSFATAL);
483 						q = empcl == cl ? empty : buffer;
484 						for (; q < p; q += 32)
485 							*q = SLOT_DELETED;
486 						mod |= THISMOD|FSDIRMOD;
487 					} else if (ask(0, "Truncate"))
488 						dir->fsckflags |= DIREMPWARN;
489 				}
490 				if (dir->fsckflags & DIREMPWARN) {
491 					*p = SLOT_DELETED;
492 					mod |= THISMOD|FSDIRMOD;
493 					continue;
494 				} else if (dir->fsckflags & DIREMPTY)
495 					mod |= FSERROR;
496 				empty = NULL;
497 			}
498 
499 			if (p[11] == ATTR_WIN95) {
500 				if (*p & LRFIRST) {
501 					if (shortSum != -1) {
502 						if (!invlfn) {
503 							invlfn = vallfn;
504 							invcl = valcl;
505 						}
506 					}
507 					(void)memset(longName, 0, sizeof longName);
508 					shortSum = p[13];
509 					vallfn = p;
510 					valcl = cl;
511 				} else if (shortSum != p[13]
512 					   || lidx != (*p & LRNOMASK)) {
513 					if (!invlfn) {
514 						invlfn = vallfn;
515 						invcl = valcl;
516 					}
517 					if (!invlfn) {
518 						invlfn = p;
519 						invcl = cl;
520 					}
521 					vallfn = NULL;
522 				}
523 				lidx = *p & LRNOMASK;
524 				if (lidx == 0) {
525 					if (!invlfn) {
526 						invlfn = vallfn;
527 						invcl = valcl;
528 					}
529 					vallfn = NULL;
530 					continue;
531 				}
532 				t = longName + --lidx * 13;
533 				for (k = 1; k < 11 && t < longName + sizeof(longName); k += 2) {
534 					if (!p[k] && !p[k + 1])
535 						break;
536 					*t++ = p[k];
537 					/*
538 					 * Warn about those unusable chars in msdosfs here?	XXX
539 					 */
540 					if (p[k + 1])
541 						t[-1] = '?';
542 				}
543 				if (k >= 11)
544 					for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
545 						if (!p[k] && !p[k + 1])
546 							break;
547 						*t++ = p[k];
548 						if (p[k + 1])
549 							t[-1] = '?';
550 					}
551 				if (k >= 26)
552 					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
553 						if (!p[k] && !p[k + 1])
554 							break;
555 						*t++ = p[k];
556 						if (p[k + 1])
557 							t[-1] = '?';
558 					}
559 				if (t >= longName + sizeof(longName)) {
560 					pwarn("long filename too long\n");
561 					if (!invlfn) {
562 						invlfn = vallfn;
563 						invcl = valcl;
564 					}
565 					vallfn = NULL;
566 				}
567 				if (p[26] | (p[27] << 8)) {
568 					pwarn("long filename record cluster start != 0\n");
569 					if (!invlfn) {
570 						invlfn = vallfn;
571 						invcl = cl;
572 					}
573 					vallfn = NULL;
574 				}
575 				continue;	/* long records don't carry further
576 						 * information */
577 			}
578 
579 			/*
580 			 * This is a standard msdosfs directory entry.
581 			 */
582 			(void)memset(&dirent, 0, sizeof dirent);
583 
584 			/*
585 			 * it's a short name record, but we need to know
586 			 * more, so get the flags first.
587 			 */
588 			dirent.flags = p[11];
589 
590 			/*
591 			 * Translate from 850 to ISO here		XXX
592 			 */
593 			for (j = 0; j < 8; j++)
594 				dirent.name[j] = p[j];
595 			dirent.name[8] = '\0';
596 			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
597 				dirent.name[k] = '\0';
598 			if (dirent.name[k] != '\0')
599 				k++;
600 			if (dirent.name[0] == SLOT_E5)
601 				dirent.name[0] = 0xe5;
602 
603 			if (dirent.flags & ATTR_VOLUME) {
604 				if (vallfn || invlfn) {
605 					mod |= removede(f, boot, fat,
606 							invlfn ? invlfn : vallfn, p,
607 							invlfn ? invcl : valcl, -1, 0,
608 							fullpath(dir), 2);
609 					vallfn = NULL;
610 					invlfn = NULL;
611 				}
612 				continue;
613 			}
614 
615 			if (p[8] != ' ')
616 				dirent.name[k++] = '.';
617 			for (j = 0; j < 3; j++)
618 				dirent.name[k++] = p[j+8];
619 			dirent.name[k] = '\0';
620 			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
621 				dirent.name[k] = '\0';
622 
623 			if (vallfn && shortSum != calcShortSum(p)) {
624 				if (!invlfn) {
625 					invlfn = vallfn;
626 					invcl = valcl;
627 				}
628 				vallfn = NULL;
629 			}
630 			dirent.head = p[26] | (p[27] << 8);
631 			if (boot->ClustMask == CLUST32_MASK)
632 				dirent.head |= (p[20] << 16) | (p[21] << 24);
633 			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
634 			if (vallfn) {
635 				strlcpy(dirent.lname, longName, sizeof dirent.lname);
636 				longName[0] = '\0';
637 				shortSum = -1;
638 			}
639 
640 			dirent.parent = dir;
641 			dirent.next = dir->child;
642 
643 			if (invlfn) {
644 				mod |= k = removede(f, boot, fat,
645 						    invlfn, vallfn ? vallfn : p,
646 						    invcl, vallfn ? valcl : cl, cl,
647 						    fullpath(&dirent), 0);
648 				if (mod & FSFATAL)
649 					return (FSFATAL);
650 				if (vallfn
651 				    ? (valcl == cl && vallfn != buffer)
652 				    : p != buffer)
653 					if (k & FSDIRMOD)
654 						mod |= THISMOD;
655 			}
656 
657 			vallfn = NULL; /* not used any longer */
658 			invlfn = NULL;
659 
660 			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
661 				if (dirent.head != 0) {
662 					pwarn("%s has clusters, but size 0\n",
663 					      fullpath(&dirent));
664 					if (ask(1, "Drop allocated clusters")) {
665 						p[26] = p[27] = 0;
666 						if (boot->ClustMask == CLUST32_MASK)
667 							p[20] = p[21] = 0;
668 						clearchain(boot, fat, dirent.head);
669 						dirent.head = 0;
670 						mod |= THISMOD|FSDIRMOD|FSFATMOD;
671 					} else
672 						mod |= FSERROR;
673 				}
674 			} else if (dirent.head == 0
675 				   && !strcmp(dirent.name, "..")
676 				   && dir->parent			/* XXX */
677 				   && !dir->parent->parent) {
678 				/*
679 				 *  Do nothing, the parent is the root
680 				 */
681 			} else if (dirent.head < CLUST_FIRST
682 				   || dirent.head >= boot->NumClusters
683 				   || fat[dirent.head].next == CLUST_FREE
684 				   || (fat[dirent.head].next >= CLUST_RSRVD
685 				       && fat[dirent.head].next < CLUST_EOFS)
686 				   || fat[dirent.head].head != dirent.head) {
687 				if (dirent.head == 0)
688 					pwarn("%s has no clusters\n",
689 					      fullpath(&dirent));
690 				else if (dirent.head < CLUST_FIRST
691 					 || dirent.head >= boot->NumClusters)
692 					pwarn("%s starts with cluster out of range(%u)\n",
693 					      fullpath(&dirent),
694 					      dirent.head);
695 				else if (fat[dirent.head].next == CLUST_FREE)
696 					pwarn("%s starts with free cluster\n",
697 					      fullpath(&dirent));
698 				else if (fat[dirent.head].next >= CLUST_RSRVD)
699 					pwarn("%s starts with cluster marked %s\n",
700 					      fullpath(&dirent),
701 					      rsrvdcltype(fat[dirent.head].next));
702 				else
703 					pwarn("%s doesn't start a cluster chain\n",
704 					      fullpath(&dirent));
705 				if (dirent.flags & ATTR_DIRECTORY) {
706 					if (ask(0, "Remove")) {
707 						*p = SLOT_DELETED;
708 						mod |= THISMOD|FSDIRMOD;
709 					} else
710 						mod |= FSERROR;
711 					continue;
712 				} else {
713 					if (ask(1, "Truncate")) {
714 						p[28] = p[29] = p[30] = p[31] = 0;
715 						p[26] = p[27] = 0;
716 						if (boot->ClustMask == CLUST32_MASK)
717 							p[20] = p[21] = 0;
718 						dirent.size = 0;
719 						mod |= THISMOD|FSDIRMOD;
720 					} else
721 						mod |= FSERROR;
722 				}
723 			}
724 
725 			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
726 				fat[dirent.head].flags |= FAT_USED;
727 
728 			if (dirent.flags & ATTR_DIRECTORY) {
729 				/*
730 				 * gather more info for directories
731 				 */
732 				struct dirTodoNode *n;
733 
734 				if (dirent.size) {
735 					pwarn("Directory %s has size != 0\n",
736 					      fullpath(&dirent));
737 					if (ask(1, "Correct")) {
738 						p[28] = p[29] = p[30] = p[31] = 0;
739 						dirent.size = 0;
740 						mod |= THISMOD|FSDIRMOD;
741 					} else
742 						mod |= FSERROR;
743 				}
744 				/*
745 				 * handle `.' and `..' specially
746 				 */
747 				if (strcmp(dirent.name, ".") == 0) {
748 					if (dirent.head != dir->head) {
749 						pwarn("`.' entry in %s has incorrect start cluster\n",
750 						      fullpath(dir));
751 						if (ask(1, "Correct")) {
752 							dirent.head = dir->head;
753 							p[26] = (u_char)dirent.head;
754 							p[27] = (u_char)(dirent.head >> 8);
755 							if (boot->ClustMask == CLUST32_MASK) {
756 								p[20] = (u_char)(dirent.head >> 16);
757 								p[21] = (u_char)(dirent.head >> 24);
758 							}
759 							mod |= THISMOD|FSDIRMOD;
760 						} else
761 							mod |= FSERROR;
762 					}
763 					continue;
764 				}
765 				if (strcmp(dirent.name, "..") == 0) {
766 					if (dir->parent) {		/* XXX */
767 						if (!dir->parent->parent) {
768 							if (dirent.head) {
769 								pwarn("`..' entry in %s has non-zero start cluster\n",
770 								      fullpath(dir));
771 								if (ask(1, "Correct")) {
772 									dirent.head = 0;
773 									p[26] = p[27] = 0;
774 									if (boot->ClustMask == CLUST32_MASK)
775 										p[20] = p[21] = 0;
776 									mod |= THISMOD|FSDIRMOD;
777 								} else
778 									mod |= FSERROR;
779 							}
780 						} else if (dirent.head != dir->parent->head) {
781 							pwarn("`..' entry in %s has incorrect start cluster\n",
782 							      fullpath(dir));
783 							if (ask(1, "Correct")) {
784 								dirent.head = dir->parent->head;
785 								p[26] = (u_char)dirent.head;
786 								p[27] = (u_char)(dirent.head >> 8);
787 								if (boot->ClustMask == CLUST32_MASK) {
788 									p[20] = (u_char)(dirent.head >> 16);
789 									p[21] = (u_char)(dirent.head >> 24);
790 								}
791 								mod |= THISMOD|FSDIRMOD;
792 							} else
793 								mod |= FSERROR;
794 						}
795 					}
796 					continue;
797 				}
798 
799 				/* create directory tree node */
800 				if (!(d = newDosDirEntry())) {
801 					xperror("No space for directory");
802 					return (FSFATAL);
803 				}
804 				(void)memcpy(d, &dirent, sizeof(struct dosDirEntry));
805 				/* link it into the tree */
806 				dir->child = d;
807 
808 				/* Enter this directory into the todo list */
809 				if (!(n = newDirTodo())) {
810 					xperror("No space for todo list");
811 					return (FSFATAL);
812 				}
813 				n->next = pendingDirectories;
814 				n->dir = d;
815 				pendingDirectories = n;
816 			} else {
817 				mod |= k = checksize(boot, fat, p, &dirent);
818 				if (k & FSDIRMOD)
819 					mod |= THISMOD;
820 			}
821 			boot->NumFiles++;
822 		}
823 		if (mod & THISMOD) {
824 			last *= 32;
825 			if (lseek(f, off, SEEK_SET) != off
826 			    || write(f, buffer, last) != last) {
827 				xperror("Unable to write directory");
828 				return (FSFATAL);
829 			}
830 			mod &= ~THISMOD;
831 		}
832 	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
833 	if (invlfn || vallfn)
834 		mod |= removede(f, boot, fat,
835 				invlfn ? invlfn : vallfn, p,
836 				invlfn ? invcl : valcl, -1, 0,
837 				fullpath(dir), 1);
838 	return (mod & ~THISMOD);
839 }
840 
841 int
842 handleDirTree(int dosfs, struct bootblock *boot, struct fatEntry *fat)
843 {
844 	int mod;
845 
846 	mod = readDosDirSection(dosfs, boot, fat, rootDir);
847 	if (mod & FSFATAL)
848 		return (FSFATAL);
849 
850 	if (mod & FSFATMOD) {
851 		mod &= ~FSFATMOD;
852 		mod |= writefat(dosfs, boot, fat); /* delay writing fats?	XXX */
853 	}
854 
855 	if (mod & FSFATAL)
856 		return (FSFATAL);
857 
858 	/*
859 	 * process the directory todo list
860 	 */
861 	while (pendingDirectories) {
862 		struct dosDirEntry *dir = pendingDirectories->dir;
863 		struct dirTodoNode *n = pendingDirectories->next;
864 
865 		/*
866 		 * remove TODO entry now, the list might change during
867 		 * directory reads
868 		 */
869 		freeDirTodo(pendingDirectories);
870 		pendingDirectories = n;
871 
872 		/*
873 		 * handle subdirectory
874 		 */
875 		mod |= readDosDirSection(dosfs, boot, fat, dir);
876 		if (mod & FSFATAL)
877 			return (FSFATAL);
878 		if (mod & FSFATMOD) {
879 			mod &= ~FSFATMOD;
880 			mod |= writefat(dosfs, boot, fat); /* delay writing fats? XXX */
881 		}
882 		if (mod & FSFATAL)
883 			return (FSFATAL);
884 	}
885 	return (mod);
886 }
887 
888 /*
889  * Try to reconnect a FAT chain into dir
890  */
891 static u_char *lfbuf;
892 static cl_t lfcl;
893 static off_t lfoff;
894 
895 int
896 reconnect(int dosfs, struct bootblock *boot, struct fatEntry *fat, cl_t head)
897 {
898 	struct dosDirEntry d;
899 	u_char *p;
900 
901 	if (!ask(1, "Reconnect"))
902 		return FSERROR;
903 
904 	if (!lostDir) {
905 		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
906 			if (!strcmp(lostDir->name, LOSTDIR))
907 				break;
908 		}
909 		if (!lostDir) {		/* Create LOSTDIR?		XXX */
910 			pwarn("No %s directory\n", LOSTDIR);
911 			return (FSERROR);
912 		}
913 	}
914 	if (!lfbuf) {
915 		lfbuf = malloc(boot->ClusterSize);
916 		if (!lfbuf) {
917 			xperror("No space for buffer");
918 			return (FSFATAL);
919 		}
920 		p = NULL;
921 	} else
922 		p = lfbuf;
923 	while (1) {
924 		if (p)
925 			for (; p < lfbuf + boot->ClusterSize; p += 32)
926 				if (*p == SLOT_EMPTY
927 				    || *p == SLOT_DELETED)
928 					break;
929 		if (p && p < lfbuf + boot->ClusterSize)
930 			break;
931 		lfcl = p ? fat[lfcl].next : lostDir->head;
932 		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
933 			/* Extend LOSTDIR?				XXX */
934 			pwarn("No space in %s\n", LOSTDIR);
935 			return (FSERROR);
936 		}
937 		lfoff = lfcl * boot->ClusterSize
938 		    + boot->ClusterOffset * boot->BytesPerSec;
939 		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
940 		    || read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
941 			xperror("could not read LOST.DIR");
942 			return (FSFATAL);
943 		}
944 		p = lfbuf;
945 	}
946 
947 	boot->NumFiles++;
948 	/* Ensure uniqueness of entry here!				XXX */
949 	(void)memset(&d, 0, sizeof d);
950 	snprintf(d.name, sizeof d.name, "%u", head);
951 	d.flags = 0;
952 	d.head = head;
953 	d.size = fat[head].length * boot->ClusterSize;
954 
955 	(void)memset(p, 0, 32);
956 	(void)memset(p, ' ', 11);
957 	(void)memcpy(p, d.name, strlen(d.name));
958 	p[26] = (u_char)d.head;
959 	p[27] = (u_char)(d.head >> 8);
960 	if (boot->ClustMask == CLUST32_MASK) {
961 		p[20] = (u_char)(d.head >> 16);
962 		p[21] = (u_char)(d.head >> 24);
963 	}
964 	p[28] = (u_char)d.size;
965 	p[29] = (u_char)(d.size >> 8);
966 	p[30] = (u_char)(d.size >> 16);
967 	p[31] = (u_char)(d.size >> 24);
968 	fat[head].flags |= FAT_USED;
969 	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
970 	    || write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
971 		xperror("could not write LOST.DIR");
972 		return (FSFATAL);
973 	}
974 	return (FSDIRMOD);
975 }
976 
977 void
978 finishlf(void)
979 {
980 	if (lfbuf)
981 		free(lfbuf);
982 	lfbuf = NULL;
983 }
984