xref: /openbsd-src/sbin/fsck_msdos/dir.c (revision 91f110e064cd7c194e59e019b83bb7496c1c84d4)
1 /*	$OpenBSD: dir.c,v 1.21 2009/10/27 23:59:33 deraadt 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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by Martin Husemann
21  *	and Wolfgang Solfrank.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <ctype.h>
42 #include <stdio.h>
43 #include <unistd.h>
44 #include <time.h>
45 
46 #include <sys/param.h>
47 
48 #include "ext.h"
49 
50 #define	SLOT_EMPTY	0x00		/* slot has never been used */
51 #define	SLOT_E5		0x05		/* the real value is 0xe5 */
52 #define	SLOT_DELETED	0xe5		/* file in this slot deleted */
53 
54 #define	ATTR_NORMAL	0x00		/* normal file */
55 #define	ATTR_READONLY	0x01		/* file is readonly */
56 #define	ATTR_HIDDEN	0x02		/* file is hidden */
57 #define	ATTR_SYSTEM	0x04		/* file is a system file */
58 #define	ATTR_VOLUME	0x08		/* entry is a volume label */
59 #define	ATTR_DIRECTORY	0x10		/* entry is a directory name */
60 #define	ATTR_ARCHIVE	0x20		/* file is new or modified */
61 
62 #define	ATTR_WIN95	0x0f		/* long name record */
63 
64 /*
65  * This is the format of the contents of the deTime field in the direntry
66  * structure.
67  * We don't use bitfields because we don't know how compilers for
68  * arbitrary machines will lay them out.
69  */
70 #define DT_2SECONDS_MASK	0x1F	/* seconds divided by 2 */
71 #define DT_2SECONDS_SHIFT	0
72 #define DT_MINUTES_MASK		0x7E0	/* minutes */
73 #define DT_MINUTES_SHIFT	5
74 #define DT_HOURS_MASK		0xF800	/* hours */
75 #define DT_HOURS_SHIFT		11
76 
77 /*
78  * This is the format of the contents of the deDate field in the direntry
79  * structure.
80  */
81 #define DD_DAY_MASK		0x1F	/* day of month */
82 #define DD_DAY_SHIFT		0
83 #define DD_MONTH_MASK		0x1E0	/* month */
84 #define DD_MONTH_SHIFT		5
85 #define DD_YEAR_MASK		0xFE00	/* year - 1980 */
86 #define DD_YEAR_SHIFT		9
87 
88 /* dir.c */
89 static struct dosDirEntry *newDosDirEntry(void);
90 static void freeDosDirEntry(struct dosDirEntry *);
91 static struct dirTodoNode *newDirTodo(void);
92 static void freeDirTodo(struct dirTodoNode *);
93 static char *fullpath(struct dosDirEntry *);
94 static u_char calcShortSum(u_char *);
95 static int delete(int, struct bootblock *, struct fatEntry *, cl_t, int,
96     cl_t, int, int);
97 static int removede(int, struct bootblock *, struct fatEntry *, u_char *,
98     u_char *, cl_t, cl_t, cl_t, char *, int);
99 static int checksize(struct bootblock *, struct fatEntry *, u_char *,
100     struct dosDirEntry *);
101 static int readDosDirSection(int, struct bootblock *, struct fatEntry *,
102     struct dosDirEntry *);
103 
104 /*
105  * Manage free dosDirEntry structures.
106  */
107 static struct dosDirEntry *freede;
108 
109 static struct dosDirEntry *
110 newDosDirEntry(void)
111 {
112 	struct dosDirEntry *de;
113 
114 	if (!(de = freede)) {
115 		if (!(de = (struct dosDirEntry *)malloc(sizeof *de)))
116 			return (0);
117 	} else
118 		freede = de->next;
119 	return (de);
120 }
121 
122 static void
123 freeDosDirEntry(struct dosDirEntry *de)
124 {
125 	de->next = freede;
126 	freede = de;
127 }
128 
129 /*
130  * The same for dirTodoNode structures.
131  */
132 static struct dirTodoNode *freedt;
133 
134 static struct dirTodoNode *
135 newDirTodo(void)
136 {
137 	struct dirTodoNode *dt;
138 
139 	if (!(dt = freedt)) {
140 		if (!(dt = (struct dirTodoNode *)malloc(sizeof *dt)))
141 			return (0);
142 	} else
143 		freedt = dt->next;
144 	return (dt);
145 }
146 
147 static void
148 freeDirTodo(struct dirTodoNode *dt)
149 {
150 	dt->next = freedt;
151 	freedt = dt;
152 }
153 
154 /*
155  * The stack of unread directories
156  */
157 struct dirTodoNode *pendingDirectories = NULL;
158 
159 /*
160  * Return the full pathname for a directory entry.
161  */
162 static char *
163 fullpath(struct dosDirEntry *dir)
164 {
165 	static char namebuf[MAXPATHLEN + 1];
166 	char *cp, *np;
167 	int nl;
168 
169 	cp = namebuf + sizeof namebuf;
170 	*--cp = '\0';
171 	for(;;) {
172 		np = dir->lname[0] ? dir->lname : dir->name;
173 		nl = strlen(np);
174 			/* cf dosDirEntry, sizeof(lname) < MAXPATHLEN, so test is safe */
175 		if (cp <= namebuf + 1 + nl) {
176 			*--cp = '?';
177 			break;
178 		}
179 		cp -= nl;
180 		(void)memcpy(cp, np, nl);
181 		dir = dir->parent;
182 		if (!dir)
183 			break;
184 		*--cp = '/';
185 	}
186 	return (cp);
187 }
188 
189 /*
190  * Calculate a checksum over an 8.3 alias name
191  */
192 static u_char
193 calcShortSum(u_char *p)
194 {
195 	u_char sum = 0;
196 	int i;
197 
198 	for (i = 0; i < 11; i++) {
199 		sum = (sum << 7)|(sum >> 1);	/* rotate right */
200 		sum += p[i];
201 	}
202 
203 	return (sum);
204 }
205 
206 /*
207  * Global variables temporarily used during a directory scan
208  */
209 static char longName[DOSLONGNAMELEN] = "";
210 static u_char *buffer = NULL;
211 static u_char *delbuf = NULL;
212 
213 struct dosDirEntry *rootDir;
214 static struct dosDirEntry *lostDir;
215 
216 /*
217  * Init internal state for a new directory scan.
218  */
219 int
220 resetDosDirSection(struct bootblock *boot, struct fatEntry *fat)
221 {
222 	int b1, b2;
223 	cl_t cl;
224 	int ret = FSOK;
225 
226 	b1 = boot->RootDirEnts * 32;
227 	b2 = boot->SecPerClust * boot->BytesPerSec;
228 
229 	if (!(buffer = malloc(b1 > b2 ? b1 : b2))
230 	    || !(delbuf = malloc(b2))
231 	    || !(rootDir = newDosDirEntry())) {
232 		xperror("No space for directory");
233 		return (FSFATAL);
234 	}
235 	(void)memset(rootDir, 0, sizeof *rootDir);
236 	if (boot->flags & FAT32) {
237 		if (boot->RootCl < CLUST_FIRST || boot->RootCl >= boot->NumClusters) {
238 			pfatal("Root directory starts with cluster out of range(%u)\n",
239 			       boot->RootCl);
240 			return (FSFATAL);
241 		}
242 		cl = fat[boot->RootCl].next;
243 		if (cl < CLUST_FIRST
244 		    || (cl >= CLUST_RSRVD && cl< CLUST_EOFS)
245 		    || fat[boot->RootCl].head != boot->RootCl) {
246 			if (cl == CLUST_FREE)
247 				pwarn("Root directory starts with free cluster\n");
248 			else if (cl >= CLUST_RSRVD)
249 				pwarn("Root directory starts with cluster marked %s\n",
250 				      rsrvdcltype(cl));
251 			else {
252 				pfatal("Root directory doesn't start a cluster chain\n");
253 				return (FSFATAL);
254 			}
255 			if (ask(1, "Fix")) {
256 				fat[boot->RootCl].next = CLUST_FREE;
257 				ret = FSFATMOD;
258 			} else
259 				 ret = FSFATAL;
260 		}
261 
262 		fat[boot->RootCl].flags |= FAT_USED;
263 		rootDir->head = boot->RootCl;
264 	}
265 
266 	return (ret);
267 }
268 
269 /*
270  * Cleanup after a directory scan
271  */
272 void
273 finishDosDirSection(void)
274 {
275 	struct dirTodoNode *p, *np;
276 	struct dosDirEntry *d, *nd;
277 
278 	for (p = pendingDirectories; p; p = np) {
279 		np = p->next;
280 		freeDirTodo(p);
281 	}
282 	pendingDirectories = 0;
283 	for (d = rootDir; d; d = nd) {
284 		if ((nd = d->child) != NULL) {
285 			d->child = 0;
286 			continue;
287 		}
288 		if (!(nd = d->next))
289 			nd = d->parent;
290 		freeDosDirEntry(d);
291 	}
292 	rootDir = lostDir = NULL;
293 	free(buffer);
294 	free(delbuf);
295 	buffer = NULL;
296 	delbuf = NULL;
297 }
298 
299 /*
300  * Delete directory entries between startcl, startoff and endcl, endoff.
301  */
302 static int
303 delete(int f, struct bootblock *boot, struct fatEntry *fat, cl_t startcl,
304        int startoff, cl_t endcl, int endoff, int notlast)
305 {
306 	u_char *s, *e;
307 	off_t off;
308 	int clsz = boot->SecPerClust * boot->BytesPerSec;
309 
310 	s = delbuf + startoff;
311 	e = delbuf + clsz;
312 	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
313 		if (startcl == endcl) {
314 			if (notlast)
315 				break;
316 			e = delbuf + endoff;
317 		}
318 		off = startcl * boot->SecPerClust + boot->ClusterOffset;
319 		off *= boot->BytesPerSec;
320 		if (lseek(f, off, SEEK_SET) != off
321 		    || read(f, delbuf, clsz) != clsz) {
322 			xperror("Unable to read directory");
323 			return (FSFATAL);
324 		}
325 		while (s < e) {
326 			*s = SLOT_DELETED;
327 			s += 32;
328 		}
329 		if (lseek(f, off, SEEK_SET) != off
330 		    || write(f, delbuf, clsz) != clsz) {
331 			xperror("Unable to write directory");
332 			return (FSFATAL);
333 		}
334 		if (startcl == endcl)
335 			break;
336 		startcl = fat[startcl].next;
337 		s = delbuf;
338 	}
339 	return (FSOK);
340 }
341 
342 static int
343 removede(int f, struct bootblock *boot, struct fatEntry *fat, u_char *start,
344 	 u_char *end, cl_t startcl, cl_t endcl, cl_t curcl, char *path, int type)
345 {
346 	switch (type) {
347 	case 0:
348 		pwarn("Invalid long filename entry for %s\n", path);
349 		break;
350 	case 1:
351 		pwarn("Invalid long filename entry at end of directory %s\n", path);
352 		break;
353 	case 2:
354 		pwarn("Invalid long filename entry for volume label\n");
355 		break;
356 	}
357 	if (ask(0, "Remove")) {
358 		if (startcl != curcl) {
359 			if (delete(f, boot, fat,
360 				   startcl, start - buffer,
361 				   endcl, end - buffer,
362 				   endcl == curcl) == FSFATAL)
363 				return (FSFATAL);
364 			start = buffer;
365 		}
366 		if (endcl == curcl)
367 			for (; start < end; start += 32)
368 				*start = SLOT_DELETED;
369 		return (FSDIRMOD);
370 	}
371 	return (FSERROR);
372 }
373 
374 /*
375  * Check an in-memory file entry
376  */
377 static int
378 checksize(struct bootblock *boot, struct fatEntry *fat, u_char *p,
379 	  struct dosDirEntry *dir)
380 {
381 	/*
382 	 * Check size on ordinary files
383 	 */
384 	int32_t physicalSize;
385 
386 	if (dir->head == CLUST_FREE)
387 		physicalSize = 0;
388 	else {
389 		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
390 			return (FSERROR);
391 		physicalSize = fat[dir->head].length * boot->ClusterSize;
392 	}
393 	if (physicalSize < dir->size) {
394 		pwarn("size of %s is %u, should at most be %u\n",
395 		      fullpath(dir), dir->size, physicalSize);
396 		if (ask(1, "Truncate")) {
397 			dir->size = physicalSize;
398 			p[28] = (u_char)physicalSize;
399 			p[29] = (u_char)(physicalSize >> 8);
400 			p[30] = (u_char)(physicalSize >> 16);
401 			p[31] = (u_char)(physicalSize >> 24);
402 			return (FSDIRMOD);
403 		} else
404 			return (FSERROR);
405 	} else if (physicalSize - dir->size >= boot->ClusterSize) {
406 		pwarn("%s has too many clusters allocated\n",
407 		      fullpath(dir));
408 		if (ask(1, "Drop superfluous clusters")) {
409 			cl_t cl;
410 			u_int32_t sz = 0;
411 
412 			for (cl = dir->head; (sz += boot->ClusterSize) < dir->size;)
413 				cl = fat[cl].next;
414 			clearchain(boot, fat, fat[cl].next);
415 			fat[cl].next = CLUST_EOF;
416 			return (FSFATMOD);
417 		} else
418 			return (FSERROR);
419 	}
420 	return (FSOK);
421 }
422 
423 /*
424  * Read a directory and
425  *   - resolve long name records
426  *   - enter file and directory records into the parent's list
427  *   - push directories onto the todo-stack
428  */
429 static int
430 readDosDirSection(int f, struct bootblock *boot, struct fatEntry *fat,
431 		  struct dosDirEntry *dir)
432 {
433 	struct dosDirEntry dirent, *d;
434 	u_char *p, *vallfn, *invlfn, *empty;
435 	off_t off;
436 	int i, j, k, last;
437 	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
438 	char *t;
439 	u_int lidx = 0;
440 	int shortSum;
441 	int mod = FSOK;
442 #define	THISMOD	0x8000			/* Only used within this routine */
443 
444 	cl = dir->head;
445 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
446 		/*
447 		 * Already handled somewhere else.
448 		 */
449 		return (FSOK);
450 	}
451 	shortSum = -1;
452 	vallfn = invlfn = empty = NULL;
453 	do {
454 		if (!(boot->flags & FAT32) && !dir->parent) {
455 			last = boot->RootDirEnts * 32;
456 			off = boot->ResSectors + boot->FATs * boot->FATsecs;
457 		} else {
458 			last = boot->SecPerClust * boot->BytesPerSec;
459 			off = cl * boot->SecPerClust + boot->ClusterOffset;
460 		}
461 
462 		off *= boot->BytesPerSec;
463 		if (lseek(f, off, SEEK_SET) != off
464 		    || read(f, buffer, last) != last) {
465 			xperror("Unable to read directory");
466 			return (FSFATAL);
467 		}
468 		last /= 32;
469 		/*
470 		 * Check `.' and `..' entries here?			XXX
471 		 */
472 		for (p = buffer, i = 0; i < last; i++, p += 32) {
473 			if (dir->fsckflags & DIREMPWARN) {
474 				*p = SLOT_EMPTY;
475 				continue;
476 			}
477 
478 			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
479 				if (*p == SLOT_EMPTY) {
480 					dir->fsckflags |= DIREMPTY;
481 					empty = p;
482 					empcl = cl;
483 				}
484 				continue;
485 			}
486 
487 			if (dir->fsckflags & DIREMPTY) {
488 				if (!(dir->fsckflags & DIREMPWARN)) {
489 					pwarn("%s has entries after end of directory\n",
490 					      fullpath(dir));
491 					if (ask(1, "Extend")) {
492 						u_char *q;
493 
494 						dir->fsckflags &= ~DIREMPTY;
495 						if (delete(f, boot, fat,
496 							   empcl, empty - buffer,
497 							   cl, p - buffer, 1) == FSFATAL)
498 							return (FSFATAL);
499 						q = empcl == cl ? empty : buffer;
500 						for (; q < p; q += 32)
501 							*q = SLOT_DELETED;
502 						mod |= THISMOD|FSDIRMOD;
503 					} else if (ask(0, "Truncate"))
504 						dir->fsckflags |= DIREMPWARN;
505 				}
506 				if (dir->fsckflags & DIREMPWARN) {
507 					*p = SLOT_DELETED;
508 					mod |= THISMOD|FSDIRMOD;
509 					continue;
510 				} else if (dir->fsckflags & DIREMPTY)
511 					mod |= FSERROR;
512 				empty = NULL;
513 			}
514 
515 			if (p[11] == ATTR_WIN95) {
516 				if (*p & LRFIRST) {
517 					if (shortSum != -1) {
518 						if (!invlfn) {
519 							invlfn = vallfn;
520 							invcl = valcl;
521 						}
522 					}
523 					(void)memset(longName, 0, sizeof longName);
524 					shortSum = p[13];
525 					vallfn = p;
526 					valcl = cl;
527 				} else if (shortSum != p[13]
528 					   || lidx != (*p & LRNOMASK)) {
529 					if (!invlfn) {
530 						invlfn = vallfn;
531 						invcl = valcl;
532 					}
533 					if (!invlfn) {
534 						invlfn = p;
535 						invcl = cl;
536 					}
537 					vallfn = NULL;
538 				}
539 				lidx = *p & LRNOMASK;
540 				t = longName + --lidx * 13;
541 				for (k = 1; k < 11 && t < longName + sizeof(longName); k += 2) {
542 					if (!p[k] && !p[k + 1])
543 						break;
544 					*t++ = p[k];
545 					/*
546 					 * Warn about those unusable chars in msdosfs here?	XXX
547 					 */
548 					if (p[k + 1])
549 						t[-1] = '?';
550 				}
551 				if (k >= 11)
552 					for (k = 14; k < 26 && 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 (k >= 26)
560 					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
561 						if (!p[k] && !p[k + 1])
562 							break;
563 						*t++ = p[k];
564 						if (p[k + 1])
565 							t[-1] = '?';
566 					}
567 				if (t >= longName + sizeof(longName)) {
568 					pwarn("long filename too long\n");
569 					if (!invlfn) {
570 						invlfn = vallfn;
571 						invcl = valcl;
572 					}
573 					vallfn = NULL;
574 				}
575 				if (p[26] | (p[27] << 8)) {
576 					pwarn("long filename record cluster start != 0\n");
577 					if (!invlfn) {
578 						invlfn = vallfn;
579 						invcl = cl;
580 					}
581 					vallfn = NULL;
582 				}
583 				continue;	/* long records don't carry further
584 						 * information */
585 			}
586 
587 			/*
588 			 * This is a standard msdosfs directory entry.
589 			 */
590 			(void)memset(&dirent, 0, sizeof dirent);
591 
592 			/*
593 			 * it's a short name record, but we need to know
594 			 * more, so get the flags first.
595 			 */
596 			dirent.flags = p[11];
597 
598 			/*
599 			 * Translate from 850 to ISO here		XXX
600 			 */
601 			for (j = 0; j < 8; j++)
602 				dirent.name[j] = p[j];
603 			dirent.name[8] = '\0';
604 			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
605 				dirent.name[k] = '\0';
606 			if (dirent.name[k] != '\0')
607 				k++;
608 			if (dirent.name[0] == SLOT_E5)
609 				dirent.name[0] = 0xe5;
610 
611 			if (dirent.flags & ATTR_VOLUME) {
612 				if (vallfn || invlfn) {
613 					mod |= removede(f, boot, fat,
614 							invlfn ? invlfn : vallfn, p,
615 							invlfn ? invcl : valcl, -1, 0,
616 							fullpath(dir), 2);
617 					vallfn = NULL;
618 					invlfn = NULL;
619 				}
620 				continue;
621 			}
622 
623 			if (p[8] != ' ')
624 				dirent.name[k++] = '.';
625 			for (j = 0; j < 3; j++)
626 				dirent.name[k++] = p[j+8];
627 			dirent.name[k] = '\0';
628 			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
629 				dirent.name[k] = '\0';
630 
631 			if (vallfn && shortSum != calcShortSum(p)) {
632 				if (!invlfn) {
633 					invlfn = vallfn;
634 					invcl = valcl;
635 				}
636 				vallfn = NULL;
637 			}
638 			dirent.head = p[26] | (p[27] << 8);
639 			if (boot->ClustMask == CLUST32_MASK)
640 				dirent.head |= (p[20] << 16) | (p[21] << 24);
641 			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
642 			if (vallfn) {
643 				strlcpy(dirent.lname, longName, sizeof dirent.lname);
644 				longName[0] = '\0';
645 				shortSum = -1;
646 			}
647 
648 			dirent.parent = dir;
649 			dirent.next = dir->child;
650 
651 			if (invlfn) {
652 				mod |= k = removede(f, boot, fat,
653 						    invlfn, vallfn ? vallfn : p,
654 						    invcl, vallfn ? valcl : cl, cl,
655 						    fullpath(&dirent), 0);
656 				if (mod & FSFATAL)
657 					return (FSFATAL);
658 				if (vallfn
659 				    ? (valcl == cl && vallfn != buffer)
660 				    : p != buffer)
661 					if (k & FSDIRMOD)
662 						mod |= THISMOD;
663 			}
664 
665 			vallfn = NULL; /* not used any longer */
666 			invlfn = NULL;
667 
668 			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
669 				if (dirent.head != 0) {
670 					pwarn("%s has clusters, but size 0\n",
671 					      fullpath(&dirent));
672 					if (ask(1, "Drop allocated clusters")) {
673 						p[26] = p[27] = 0;
674 						if (boot->ClustMask == CLUST32_MASK)
675 							p[20] = p[21] = 0;
676 						clearchain(boot, fat, dirent.head);
677 						dirent.head = 0;
678 						mod |= THISMOD|FSDIRMOD|FSFATMOD;
679 					} else
680 						mod |= FSERROR;
681 				}
682 			} else if (dirent.head == 0
683 				   && !strcmp(dirent.name, "..")
684 				   && dir->parent			/* XXX */
685 				   && !dir->parent->parent) {
686 				/*
687 				 *  Do nothing, the parent is the root
688 				 */
689 			} else if (dirent.head < CLUST_FIRST
690 				   || dirent.head >= boot->NumClusters
691 				   || fat[dirent.head].next == CLUST_FREE
692 				   || (fat[dirent.head].next >= CLUST_RSRVD
693 				       && fat[dirent.head].next < CLUST_EOFS)
694 				   || fat[dirent.head].head != dirent.head) {
695 				if (dirent.head == 0)
696 					pwarn("%s has no clusters\n",
697 					      fullpath(&dirent));
698 				else if (dirent.head < CLUST_FIRST
699 					 || dirent.head >= boot->NumClusters)
700 					pwarn("%s starts with cluster out of range(%u)\n",
701 					      fullpath(&dirent),
702 					      dirent.head);
703 				else if (fat[dirent.head].next == CLUST_FREE)
704 					pwarn("%s starts with free cluster\n",
705 					      fullpath(&dirent));
706 				else if (fat[dirent.head].next >= CLUST_RSRVD)
707 					pwarn("%s starts with cluster marked %s\n",
708 					      fullpath(&dirent),
709 					      rsrvdcltype(fat[dirent.head].next));
710 				else
711 					pwarn("%s doesn't start a cluster chain\n",
712 					      fullpath(&dirent));
713 				if (dirent.flags & ATTR_DIRECTORY) {
714 					if (ask(0, "Remove")) {
715 						*p = SLOT_DELETED;
716 						mod |= THISMOD|FSDIRMOD;
717 					} else
718 						mod |= FSERROR;
719 					continue;
720 				} else {
721 					if (ask(1, "Truncate")) {
722 						p[28] = p[29] = p[30] = p[31] = 0;
723 						p[26] = p[27] = 0;
724 						if (boot->ClustMask == CLUST32_MASK)
725 							p[20] = p[21] = 0;
726 						dirent.size = 0;
727 						mod |= THISMOD|FSDIRMOD;
728 					} else
729 						mod |= FSERROR;
730 				}
731 			}
732 
733 			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
734 				fat[dirent.head].flags |= FAT_USED;
735 
736 			if (dirent.flags & ATTR_DIRECTORY) {
737 				/*
738 				 * gather more info for directories
739 				 */
740 				struct dirTodoNode *n;
741 
742 				if (dirent.size) {
743 					pwarn("Directory %s has size != 0\n",
744 					      fullpath(&dirent));
745 					if (ask(1, "Correct")) {
746 						p[28] = p[29] = p[30] = p[31] = 0;
747 						dirent.size = 0;
748 						mod |= THISMOD|FSDIRMOD;
749 					} else
750 						mod |= FSERROR;
751 				}
752 				/*
753 				 * handle `.' and `..' specially
754 				 */
755 				if (strcmp(dirent.name, ".") == 0) {
756 					if (dirent.head != dir->head) {
757 						pwarn("`.' entry in %s has incorrect start cluster\n",
758 						      fullpath(dir));
759 						if (ask(1, "Correct")) {
760 							dirent.head = dir->head;
761 							p[26] = (u_char)dirent.head;
762 							p[27] = (u_char)(dirent.head >> 8);
763 							if (boot->ClustMask == CLUST32_MASK) {
764 								p[20] = (u_char)(dirent.head >> 16);
765 								p[21] = (u_char)(dirent.head >> 24);
766 							}
767 							mod |= THISMOD|FSDIRMOD;
768 						} else
769 							mod |= FSERROR;
770 					}
771 					continue;
772 				}
773 				if (strcmp(dirent.name, "..") == 0) {
774 					if (dir->parent) {		/* XXX */
775 						if (!dir->parent->parent) {
776 							if (dirent.head) {
777 								pwarn("`..' entry in %s has non-zero start cluster\n",
778 								      fullpath(dir));
779 								if (ask(1, "Correct")) {
780 									dirent.head = 0;
781 									p[26] = p[27] = 0;
782 									if (boot->ClustMask == CLUST32_MASK)
783 										p[20] = p[21] = 0;
784 									mod |= THISMOD|FSDIRMOD;
785 								} else
786 									mod |= FSERROR;
787 							}
788 						} else if (dirent.head != dir->parent->head) {
789 							pwarn("`..' entry in %s has incorrect start cluster\n",
790 							      fullpath(dir));
791 							if (ask(1, "Correct")) {
792 								dirent.head = dir->parent->head;
793 								p[26] = (u_char)dirent.head;
794 								p[27] = (u_char)(dirent.head >> 8);
795 								if (boot->ClustMask == CLUST32_MASK) {
796 									p[20] = (u_char)(dirent.head >> 16);
797 									p[21] = (u_char)(dirent.head >> 24);
798 								}
799 								mod |= THISMOD|FSDIRMOD;
800 							} else
801 								mod |= FSERROR;
802 						}
803 					}
804 					continue;
805 				}
806 
807 				/* create directory tree node */
808 				if (!(d = newDosDirEntry())) {
809 					xperror("No space for directory");
810 					return (FSFATAL);
811 				}
812 				(void)memcpy(d, &dirent, sizeof(struct dosDirEntry));
813 				/* link it into the tree */
814 				dir->child = d;
815 
816 				/* Enter this directory into the todo list */
817 				if (!(n = newDirTodo())) {
818 					xperror("No space for todo list");
819 					return (FSFATAL);
820 				}
821 				n->next = pendingDirectories;
822 				n->dir = d;
823 				pendingDirectories = n;
824 			} else {
825 				mod |= k = checksize(boot, fat, p, &dirent);
826 				if (k & FSDIRMOD)
827 					mod |= THISMOD;
828 			}
829 			boot->NumFiles++;
830 		}
831 		if (mod & THISMOD) {
832 			last *= 32;
833 			if (lseek(f, off, SEEK_SET) != off
834 			    || write(f, buffer, last) != last) {
835 				xperror("Unable to write directory");
836 				return (FSFATAL);
837 			}
838 			mod &= ~THISMOD;
839 		}
840 	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
841 	if (invlfn || vallfn)
842 		mod |= removede(f, boot, fat,
843 				invlfn ? invlfn : vallfn, p,
844 				invlfn ? invcl : valcl, -1, 0,
845 				fullpath(dir), 1);
846 	return (mod & ~THISMOD);
847 }
848 
849 int
850 handleDirTree(int dosfs, struct bootblock *boot, struct fatEntry *fat)
851 {
852 	int mod;
853 
854 	mod = readDosDirSection(dosfs, boot, fat, rootDir);
855 	if (mod & FSFATAL)
856 		return (FSFATAL);
857 
858 	if (mod & FSFATMOD) {
859 		mod &= ~FSFATMOD;
860 		mod |= writefat(dosfs, boot, fat); /* delay writing fats?	XXX */
861 	}
862 
863 	if (mod & FSFATAL)
864 		return (FSFATAL);
865 
866 	/*
867 	 * process the directory todo list
868 	 */
869 	while (pendingDirectories) {
870 		struct dosDirEntry *dir = pendingDirectories->dir;
871 		struct dirTodoNode *n = pendingDirectories->next;
872 
873 		/*
874 		 * remove TODO entry now, the list might change during
875 		 * directory reads
876 		 */
877 		freeDirTodo(pendingDirectories);
878 		pendingDirectories = n;
879 
880 		/*
881 		 * handle subdirectory
882 		 */
883 		mod |= readDosDirSection(dosfs, boot, fat, dir);
884 		if (mod & FSFATAL)
885 			return (FSFATAL);
886 		if (mod & FSFATMOD) {
887 			mod &= ~FSFATMOD;
888 			mod |= writefat(dosfs, boot, fat); /* delay writing fats? XXX */
889 		}
890 		if (mod & FSFATAL)
891 			return (FSFATAL);
892 	}
893 	return (mod);
894 }
895 
896 /*
897  * Try to reconnect a FAT chain into dir
898  */
899 static u_char *lfbuf;
900 static cl_t lfcl;
901 static off_t lfoff;
902 
903 int
904 reconnect(int dosfs, struct bootblock *boot, struct fatEntry *fat, cl_t head)
905 {
906 	struct dosDirEntry d;
907 	u_char *p;
908 
909 	if (!ask(1, "Reconnect"))
910 		return FSERROR;
911 
912 	if (!lostDir) {
913 		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
914 			if (!strcmp(lostDir->name, LOSTDIR))
915 				break;
916 		}
917 		if (!lostDir) {		/* Create LOSTDIR?		XXX */
918 			pwarn("No %s directory\n", LOSTDIR);
919 			return (FSERROR);
920 		}
921 	}
922 	if (!lfbuf) {
923 		lfbuf = malloc(boot->ClusterSize);
924 		if (!lfbuf) {
925 			xperror("No space for buffer");
926 			return (FSFATAL);
927 		}
928 		p = NULL;
929 	} else
930 		p = lfbuf;
931 	while (1) {
932 		if (p)
933 			for (; p < lfbuf + boot->ClusterSize; p += 32)
934 				if (*p == SLOT_EMPTY
935 				    || *p == SLOT_DELETED)
936 					break;
937 		if (p && p < lfbuf + boot->ClusterSize)
938 			break;
939 		lfcl = p ? fat[lfcl].next : lostDir->head;
940 		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
941 			/* Extend LOSTDIR?				XXX */
942 			pwarn("No space in %s\n", LOSTDIR);
943 			return (FSERROR);
944 		}
945 		lfoff = lfcl * boot->ClusterSize
946 		    + boot->ClusterOffset * boot->BytesPerSec;
947 		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
948 		    || read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
949 			xperror("could not read LOST.DIR");
950 			return (FSFATAL);
951 		}
952 		p = lfbuf;
953 	}
954 
955 	boot->NumFiles++;
956 	/* Ensure uniqueness of entry here!				XXX */
957 	(void)memset(&d, 0, sizeof d);
958 	snprintf(d.name, sizeof d.name, "%u", head);
959 	d.flags = 0;
960 	d.head = head;
961 	d.size = fat[head].length * boot->ClusterSize;
962 
963 	(void)memset(p, 0, 32);
964 	(void)memset(p, ' ', 11);
965 	(void)memcpy(p, d.name, strlen(d.name));
966 	p[26] = (u_char)d.head;
967 	p[27] = (u_char)(d.head >> 8);
968 	if (boot->ClustMask == CLUST32_MASK) {
969 		p[20] = (u_char)(d.head >> 16);
970 		p[21] = (u_char)(d.head >> 24);
971 	}
972 	p[28] = (u_char)d.size;
973 	p[29] = (u_char)(d.size >> 8);
974 	p[30] = (u_char)(d.size >> 16);
975 	p[31] = (u_char)(d.size >> 24);
976 	fat[head].flags |= FAT_USED;
977 	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
978 	    || write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
979 		xperror("could not write LOST.DIR");
980 		return (FSFATAL);
981 	}
982 	return (FSDIRMOD);
983 }
984 
985 void
986 finishlf(void)
987 {
988 	if (lfbuf)
989 		free(lfbuf);
990 	lfbuf = NULL;
991 }
992