xref: /freebsd/sbin/fsck_msdosfs/dir.c (revision ec65e4f8d0654361df5e97d4de3518edebf76b46)
1 /*
2  * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
3  * Copyright (c) 1995 Martin Husemann
4  * Some structure declaration borrowed from Paul Popelka
5  * (paulp@uts.amdahl.com), see /sys/msdosfs/ for reference.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 
29 #include <sys/cdefs.h>
30 #ifndef lint
31 __RCSID("$NetBSD: dir.c,v 1.20 2006/06/05 16:51:18 christos Exp $");
32 static const char rcsid[] =
33   "$FreeBSD$";
34 #endif /* not lint */
35 
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <ctype.h>
40 #include <unistd.h>
41 #include <time.h>
42 
43 #include <sys/param.h>
44 
45 #include "ext.h"
46 #include "fsutil.h"
47 
48 #define	SLOT_EMPTY	0x00		/* slot has never been used */
49 #define	SLOT_E5		0x05		/* the real value is 0xe5 */
50 #define	SLOT_DELETED	0xe5		/* file in this slot deleted */
51 
52 #define	ATTR_NORMAL	0x00		/* normal file */
53 #define	ATTR_READONLY	0x01		/* file is readonly */
54 #define	ATTR_HIDDEN	0x02		/* file is hidden */
55 #define	ATTR_SYSTEM	0x04		/* file is a system file */
56 #define	ATTR_VOLUME	0x08		/* entry is a volume label */
57 #define	ATTR_DIRECTORY	0x10		/* entry is a directory name */
58 #define	ATTR_ARCHIVE	0x20		/* file is new or modified */
59 
60 #define	ATTR_WIN95	0x0f		/* long name record */
61 
62 /*
63  * This is the format of the contents of the deTime field in the direntry
64  * structure.
65  * We don't use bitfields because we don't know how compilers for
66  * arbitrary machines will lay them out.
67  */
68 #define DT_2SECONDS_MASK	0x1F	/* seconds divided by 2 */
69 #define DT_2SECONDS_SHIFT	0
70 #define DT_MINUTES_MASK		0x7E0	/* minutes */
71 #define DT_MINUTES_SHIFT	5
72 #define DT_HOURS_MASK		0xF800	/* hours */
73 #define DT_HOURS_SHIFT		11
74 
75 /*
76  * This is the format of the contents of the deDate field in the direntry
77  * structure.
78  */
79 #define DD_DAY_MASK		0x1F	/* day of month */
80 #define DD_DAY_SHIFT		0
81 #define DD_MONTH_MASK		0x1E0	/* month */
82 #define DD_MONTH_SHIFT		5
83 #define DD_YEAR_MASK		0xFE00	/* year - 1980 */
84 #define DD_YEAR_SHIFT		9
85 
86 
87 /* dir.c */
88 static struct dosDirEntry *newDosDirEntry(void);
89 static void freeDosDirEntry(struct dosDirEntry *);
90 static struct dirTodoNode *newDirTodo(void);
91 static void freeDirTodo(struct dirTodoNode *);
92 static char *fullpath(struct dosDirEntry *);
93 static u_char calcShortSum(u_char *);
94 static int delete(int, struct bootblock *, struct fatEntry *, cl_t, int,
95     cl_t, int, int);
96 static int removede(int, struct bootblock *, struct fatEntry *, u_char *,
97     u_char *, cl_t, cl_t, cl_t, char *, int);
98 static int checksize(struct bootblock *, struct fatEntry *, u_char *,
99     struct dosDirEntry *);
100 static int readDosDirSection(int, struct bootblock *, struct fatEntry *,
101     struct dosDirEntry *);
102 
103 /*
104  * Manage free dosDirEntry structures.
105  */
106 static struct dosDirEntry *freede;
107 
108 static struct dosDirEntry *
109 newDosDirEntry(void)
110 {
111 	struct dosDirEntry *de;
112 
113 	if (!(de = freede)) {
114 		if (!(de = (struct dosDirEntry *)malloc(sizeof *de)))
115 			return 0;
116 	} else
117 		freede = de->next;
118 	return de;
119 }
120 
121 static void
122 freeDosDirEntry(struct dosDirEntry *de)
123 {
124 	de->next = freede;
125 	freede = de;
126 }
127 
128 /*
129  * The same for dirTodoNode structures.
130  */
131 static struct dirTodoNode *freedt;
132 
133 static struct dirTodoNode *
134 newDirTodo(void)
135 {
136 	struct dirTodoNode *dt;
137 
138 	if (!(dt = freedt)) {
139 		if (!(dt = (struct dirTodoNode *)malloc(sizeof *dt)))
140 			return 0;
141 	} else
142 		freedt = dt->next;
143 	return dt;
144 }
145 
146 static void
147 freeDirTodo(struct dirTodoNode *dt)
148 {
149 	dt->next = freedt;
150 	freedt = dt;
151 }
152 
153 /*
154  * The stack of unread directories
155  */
156 static struct dirTodoNode *pendingDirectories = NULL;
157 
158 /*
159  * Return the full pathname for a directory entry.
160  */
161 static char *
162 fullpath(struct dosDirEntry *dir)
163 {
164 	static char namebuf[MAXPATHLEN + 1];
165 	char *cp, *np;
166 	int nl;
167 
168 	cp = namebuf + sizeof namebuf - 1;
169 	*cp = '\0';
170 	do {
171 		np = dir->lname[0] ? dir->lname : dir->name;
172 		nl = strlen(np);
173 		if ((cp -= nl) <= namebuf + 1)
174 			break;
175 		memcpy(cp, np, nl);
176 		*--cp = '/';
177 	} while ((dir = dir->parent) != NULL);
178 	if (dir)
179 		*--cp = '?';
180 	else
181 		cp++;
182 	return cp;
183 }
184 
185 /*
186  * Calculate a checksum over an 8.3 alias name
187  */
188 static u_char
189 calcShortSum(u_char *p)
190 {
191 	u_char sum = 0;
192 	int i;
193 
194 	for (i = 0; i < 11; i++) {
195 		sum = (sum << 7)|(sum >> 1);	/* rotate right */
196 		sum += p[i];
197 	}
198 
199 	return sum;
200 }
201 
202 /*
203  * Global variables temporarily used during a directory scan
204  */
205 static char longName[DOSLONGNAMELEN] = "";
206 static u_char *buffer = NULL;
207 static u_char *delbuf = NULL;
208 
209 static struct dosDirEntry *rootDir;
210 static struct dosDirEntry *lostDir;
211 
212 /*
213  * Init internal state for a new directory scan.
214  */
215 int
216 resetDosDirSection(struct bootblock *boot, struct fatEntry *fat)
217 {
218 	int b1, b2;
219 	cl_t cl;
220 	int ret = FSOK;
221 	size_t len;
222 
223 	b1 = boot->bpbRootDirEnts * 32;
224 	b2 = boot->bpbSecPerClust * boot->bpbBytesPerSec;
225 
226 	if ((buffer = malloc(len = MAX(b1, b2))) == NULL) {
227 		perr("No space for directory buffer (%zu)", len);
228 		return FSFATAL;
229 	}
230 
231 	if ((delbuf = malloc(len = b2)) == NULL) {
232 		free(buffer);
233 		perr("No space for directory delbuf (%zu)", len);
234 		return FSFATAL;
235 	}
236 
237 	if ((rootDir = newDosDirEntry()) == NULL) {
238 		free(buffer);
239 		free(delbuf);
240 		perr("No space for directory entry");
241 		return FSFATAL;
242 	}
243 
244 	memset(rootDir, 0, sizeof *rootDir);
245 	if (boot->flags & FAT32) {
246 		if (boot->bpbRootClust < CLUST_FIRST ||
247 		    boot->bpbRootClust >= boot->NumClusters) {
248 			pfatal("Root directory starts with cluster out of range(%u)",
249 			       boot->bpbRootClust);
250 			return FSFATAL;
251 		}
252 		cl = fat[boot->bpbRootClust].next;
253 		if (cl < CLUST_FIRST
254 		    || (cl >= CLUST_RSRVD && cl< CLUST_EOFS)
255 		    || fat[boot->bpbRootClust].head != boot->bpbRootClust) {
256 			if (cl == CLUST_FREE)
257 				pwarn("Root directory starts with free cluster\n");
258 			else if (cl >= CLUST_RSRVD)
259 				pwarn("Root directory starts with cluster marked %s\n",
260 				      rsrvdcltype(cl));
261 			else {
262 				pfatal("Root directory doesn't start a cluster chain");
263 				return FSFATAL;
264 			}
265 			if (ask(1, "Fix")) {
266 				fat[boot->bpbRootClust].next = CLUST_FREE;
267 				ret = FSFATMOD;
268 			} else
269 				ret = FSFATAL;
270 		}
271 
272 		fat[boot->bpbRootClust].flags |= FAT_USED;
273 		rootDir->head = boot->bpbRootClust;
274 	}
275 
276 	return ret;
277 }
278 
279 /*
280  * Cleanup after a directory scan
281  */
282 void
283 finishDosDirSection(void)
284 {
285 	struct dirTodoNode *p, *np;
286 	struct dosDirEntry *d, *nd;
287 
288 	for (p = pendingDirectories; p; p = np) {
289 		np = p->next;
290 		freeDirTodo(p);
291 	}
292 	pendingDirectories = NULL;
293 	for (d = rootDir; d; d = nd) {
294 		if ((nd = d->child) != NULL) {
295 			d->child = 0;
296 			continue;
297 		}
298 		if (!(nd = d->next))
299 			nd = d->parent;
300 		freeDosDirEntry(d);
301 	}
302 	rootDir = lostDir = NULL;
303 	free(buffer);
304 	free(delbuf);
305 	buffer = NULL;
306 	delbuf = NULL;
307 }
308 
309 /*
310  * Delete directory entries between startcl, startoff and endcl, endoff.
311  */
312 static int
313 delete(int f, struct bootblock *boot, struct fatEntry *fat, cl_t startcl,
314     int startoff, cl_t endcl, int endoff, int notlast)
315 {
316 	u_char *s, *e;
317 	off_t off;
318 	int clsz = boot->bpbSecPerClust * boot->bpbBytesPerSec;
319 
320 	s = delbuf + startoff;
321 	e = delbuf + clsz;
322 	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
323 		if (startcl == endcl) {
324 			if (notlast)
325 				break;
326 			e = delbuf + endoff;
327 		}
328 		off = startcl * boot->bpbSecPerClust + boot->ClusterOffset;
329 		off *= boot->bpbBytesPerSec;
330 		if (lseek(f, off, SEEK_SET) != off
331 		    || read(f, delbuf, clsz) != clsz) {
332 			perr("Unable to read directory");
333 			return FSFATAL;
334 		}
335 		while (s < e) {
336 			*s = SLOT_DELETED;
337 			s += 32;
338 		}
339 		if (lseek(f, off, SEEK_SET) != off
340 		    || write(f, delbuf, clsz) != clsz) {
341 			perr("Unable to write directory");
342 			return FSFATAL;
343 		}
344 		if (startcl == endcl)
345 			break;
346 		startcl = fat[startcl].next;
347 		s = delbuf;
348 	}
349 	return FSOK;
350 }
351 
352 static int
353 removede(int f, struct bootblock *boot, struct fatEntry *fat, u_char *start,
354     u_char *end, cl_t startcl, cl_t endcl, cl_t curcl, char *path, int type)
355 {
356 	switch (type) {
357 	case 0:
358 		pwarn("Invalid long filename entry for %s\n", path);
359 		break;
360 	case 1:
361 		pwarn("Invalid long filename entry at end of directory %s\n",
362 		    path);
363 		break;
364 	case 2:
365 		pwarn("Invalid long filename entry for volume label\n");
366 		break;
367 	}
368 	if (ask(0, "Remove")) {
369 		if (startcl != curcl) {
370 			if (delete(f, boot, fat,
371 				   startcl, start - buffer,
372 				   endcl, end - buffer,
373 				   endcl == curcl) == FSFATAL)
374 				return FSFATAL;
375 			start = buffer;
376 		}
377 		/* startcl is < CLUST_FIRST for !fat32 root */
378 		if ((endcl == curcl) || (startcl < CLUST_FIRST))
379 			for (; start < end; start += 32)
380 				*start = SLOT_DELETED;
381 		return FSDIRMOD;
382 	}
383 	return FSERROR;
384 }
385 
386 /*
387  * Check an in-memory file entry
388  */
389 static int
390 checksize(struct bootblock *boot, struct fatEntry *fat, u_char *p,
391     struct dosDirEntry *dir)
392 {
393 	/*
394 	 * Check size on ordinary files
395 	 */
396 	u_int32_t physicalSize;
397 
398 	if (dir->head == CLUST_FREE)
399 		physicalSize = 0;
400 	else {
401 		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
402 			return FSERROR;
403 		physicalSize = fat[dir->head].length * boot->ClusterSize;
404 	}
405 	if (physicalSize < dir->size) {
406 		pwarn("size of %s is %u, should at most be %u\n",
407 		      fullpath(dir), dir->size, physicalSize);
408 		if (ask(1, "Truncate")) {
409 			dir->size = physicalSize;
410 			p[28] = (u_char)physicalSize;
411 			p[29] = (u_char)(physicalSize >> 8);
412 			p[30] = (u_char)(physicalSize >> 16);
413 			p[31] = (u_char)(physicalSize >> 24);
414 			return FSDIRMOD;
415 		} else
416 			return FSERROR;
417 	} else if (physicalSize - dir->size >= boot->ClusterSize) {
418 		pwarn("%s has too many clusters allocated\n",
419 		      fullpath(dir));
420 		if (ask(1, "Drop superfluous clusters")) {
421 			cl_t cl;
422 			u_int32_t sz, len;
423 
424 			for (cl = dir->head, len = sz = 0;
425 			    (sz += boot->ClusterSize) < dir->size; len++)
426 				cl = fat[cl].next;
427 			clearchain(boot, fat, fat[cl].next);
428 			fat[cl].next = CLUST_EOF;
429 			fat[dir->head].length = len;
430 			return FSFATMOD;
431 		} else
432 			return FSERROR;
433 	}
434 	return FSOK;
435 }
436 
437 /*
438  * Read a directory and
439  *   - resolve long name records
440  *   - enter file and directory records into the parent's list
441  *   - push directories onto the todo-stack
442  */
443 static int
444 readDosDirSection(int f, struct bootblock *boot, struct fatEntry *fat,
445     struct dosDirEntry *dir)
446 {
447 	struct dosDirEntry dirent, *d;
448 	u_char *p, *vallfn, *invlfn, *empty;
449 	off_t off;
450 	int i, j, k, last;
451 	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
452 	char *t;
453 	u_int lidx = 0;
454 	int shortSum;
455 	int mod = FSOK;
456 #define	THISMOD	0x8000			/* Only used within this routine */
457 
458 	cl = dir->head;
459 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
460 		/*
461 		 * Already handled somewhere else.
462 		 */
463 		return FSOK;
464 	}
465 	shortSum = -1;
466 	vallfn = invlfn = empty = NULL;
467 	do {
468 		if (!(boot->flags & FAT32) && !dir->parent) {
469 			last = boot->bpbRootDirEnts * 32;
470 			off = boot->bpbResSectors + boot->bpbFATs *
471 			    boot->FATsecs;
472 		} else {
473 			last = boot->bpbSecPerClust * boot->bpbBytesPerSec;
474 			off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
475 		}
476 
477 		off *= boot->bpbBytesPerSec;
478 		if (lseek(f, off, SEEK_SET) != off
479 		    || read(f, buffer, last) != last) {
480 			perr("Unable to read directory");
481 			return FSFATAL;
482 		}
483 		last /= 32;
484 		/*
485 		 * Check `.' and `..' entries here?			XXX
486 		 */
487 		for (p = buffer, i = 0; i < last; i++, p += 32) {
488 			if (dir->fsckflags & DIREMPWARN) {
489 				*p = SLOT_EMPTY;
490 				continue;
491 			}
492 
493 			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
494 				if (*p == SLOT_EMPTY) {
495 					dir->fsckflags |= DIREMPTY;
496 					empty = p;
497 					empcl = cl;
498 				}
499 				continue;
500 			}
501 
502 			if (dir->fsckflags & DIREMPTY) {
503 				if (!(dir->fsckflags & DIREMPWARN)) {
504 					pwarn("%s has entries after end of directory\n",
505 					      fullpath(dir));
506 					if (ask(1, "Extend")) {
507 						u_char *q;
508 
509 						dir->fsckflags &= ~DIREMPTY;
510 						if (delete(f, boot, fat,
511 							   empcl, empty - buffer,
512 							   cl, p - buffer, 1) == FSFATAL)
513 							return FSFATAL;
514 						q = empcl == cl ? empty : buffer;
515 						for (; q < p; q += 32)
516 							*q = SLOT_DELETED;
517 						mod |= THISMOD|FSDIRMOD;
518 					} else if (ask(0, "Truncate"))
519 						dir->fsckflags |= DIREMPWARN;
520 				}
521 				if (dir->fsckflags & DIREMPWARN) {
522 					*p = SLOT_DELETED;
523 					mod |= THISMOD|FSDIRMOD;
524 					continue;
525 				} else if (dir->fsckflags & DIREMPTY)
526 					mod |= FSERROR;
527 				empty = NULL;
528 			}
529 
530 			if (p[11] == ATTR_WIN95) {
531 				if (*p & LRFIRST) {
532 					if (shortSum != -1) {
533 						if (!invlfn) {
534 							invlfn = vallfn;
535 							invcl = valcl;
536 						}
537 					}
538 					memset(longName, 0, sizeof longName);
539 					shortSum = p[13];
540 					vallfn = p;
541 					valcl = cl;
542 				} else if (shortSum != p[13]
543 					   || lidx != (*p & LRNOMASK)) {
544 					if (!invlfn) {
545 						invlfn = vallfn;
546 						invcl = valcl;
547 					}
548 					if (!invlfn) {
549 						invlfn = p;
550 						invcl = cl;
551 					}
552 					vallfn = NULL;
553 				}
554 				lidx = *p & LRNOMASK;
555 				t = longName + --lidx * 13;
556 				for (k = 1; k < 11 && t < longName +
557 				    sizeof(longName); k += 2) {
558 					if (!p[k] && !p[k + 1])
559 						break;
560 					*t++ = p[k];
561 					/*
562 					 * Warn about those unusable chars in msdosfs here?	XXX
563 					 */
564 					if (p[k + 1])
565 						t[-1] = '?';
566 				}
567 				if (k >= 11)
568 					for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
569 						if (!p[k] && !p[k + 1])
570 							break;
571 						*t++ = p[k];
572 						if (p[k + 1])
573 							t[-1] = '?';
574 					}
575 				if (k >= 26)
576 					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
577 						if (!p[k] && !p[k + 1])
578 							break;
579 						*t++ = p[k];
580 						if (p[k + 1])
581 							t[-1] = '?';
582 					}
583 				if (t >= longName + sizeof(longName)) {
584 					pwarn("long filename too long\n");
585 					if (!invlfn) {
586 						invlfn = vallfn;
587 						invcl = valcl;
588 					}
589 					vallfn = NULL;
590 				}
591 				if (p[26] | (p[27] << 8)) {
592 					pwarn("long filename record cluster start != 0\n");
593 					if (!invlfn) {
594 						invlfn = vallfn;
595 						invcl = cl;
596 					}
597 					vallfn = NULL;
598 				}
599 				continue;	/* long records don't carry further
600 						 * information */
601 			}
602 
603 			/*
604 			 * This is a standard msdosfs directory entry.
605 			 */
606 			memset(&dirent, 0, sizeof dirent);
607 
608 			/*
609 			 * it's a short name record, but we need to know
610 			 * more, so get the flags first.
611 			 */
612 			dirent.flags = p[11];
613 
614 			/*
615 			 * Translate from 850 to ISO here		XXX
616 			 */
617 			for (j = 0; j < 8; j++)
618 				dirent.name[j] = p[j];
619 			dirent.name[8] = '\0';
620 			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
621 				dirent.name[k] = '\0';
622 			if (dirent.name[k] != '\0')
623 				k++;
624 			if (dirent.name[0] == SLOT_E5)
625 				dirent.name[0] = 0xe5;
626 
627 			if (dirent.flags & ATTR_VOLUME) {
628 				if (vallfn || invlfn) {
629 					mod |= removede(f, boot, fat,
630 							invlfn ? invlfn : vallfn, p,
631 							invlfn ? invcl : valcl, -1, 0,
632 							fullpath(dir), 2);
633 					vallfn = NULL;
634 					invlfn = NULL;
635 				}
636 				continue;
637 			}
638 
639 			if (p[8] != ' ')
640 				dirent.name[k++] = '.';
641 			for (j = 0; j < 3; j++)
642 				dirent.name[k++] = p[j+8];
643 			dirent.name[k] = '\0';
644 			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
645 				dirent.name[k] = '\0';
646 
647 			if (vallfn && shortSum != calcShortSum(p)) {
648 				if (!invlfn) {
649 					invlfn = vallfn;
650 					invcl = valcl;
651 				}
652 				vallfn = NULL;
653 			}
654 			dirent.head = p[26] | (p[27] << 8);
655 			if (boot->ClustMask == CLUST32_MASK)
656 				dirent.head |= (p[20] << 16) | (p[21] << 24);
657 			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
658 			if (vallfn) {
659 				strlcpy(dirent.lname, longName,
660 				    sizeof(dirent.lname));
661 				longName[0] = '\0';
662 				shortSum = -1;
663 			}
664 
665 			dirent.parent = dir;
666 			dirent.next = dir->child;
667 
668 			if (invlfn) {
669 				mod |= k = removede(f, boot, fat,
670 						    invlfn, vallfn ? vallfn : p,
671 						    invcl, vallfn ? valcl : cl, cl,
672 						    fullpath(&dirent), 0);
673 				if (mod & FSFATAL)
674 					return FSFATAL;
675 				if (vallfn
676 				    ? (valcl == cl && vallfn != buffer)
677 				    : p != buffer)
678 					if (k & FSDIRMOD)
679 						mod |= THISMOD;
680 			}
681 
682 			vallfn = NULL; /* not used any longer */
683 			invlfn = NULL;
684 
685 			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
686 				if (dirent.head != 0) {
687 					pwarn("%s has clusters, but size 0\n",
688 					      fullpath(&dirent));
689 					if (ask(1, "Drop allocated clusters")) {
690 						p[26] = p[27] = 0;
691 						if (boot->ClustMask == CLUST32_MASK)
692 							p[20] = p[21] = 0;
693 						clearchain(boot, fat, dirent.head);
694 						dirent.head = 0;
695 						mod |= THISMOD|FSDIRMOD|FSFATMOD;
696 					} else
697 						mod |= FSERROR;
698 				}
699 			} else if (dirent.head == 0
700 				   && !strcmp(dirent.name, "..")
701 				   && dir->parent			/* XXX */
702 				   && !dir->parent->parent) {
703 				/*
704 				 *  Do nothing, the parent is the root
705 				 */
706 			} else if (dirent.head < CLUST_FIRST
707 				   || dirent.head >= boot->NumClusters
708 				   || fat[dirent.head].next == CLUST_FREE
709 				   || (fat[dirent.head].next >= CLUST_RSRVD
710 				       && fat[dirent.head].next < CLUST_EOFS)
711 				   || fat[dirent.head].head != dirent.head) {
712 				if (dirent.head == 0)
713 					pwarn("%s has no clusters\n",
714 					      fullpath(&dirent));
715 				else if (dirent.head < CLUST_FIRST
716 					 || dirent.head >= boot->NumClusters)
717 					pwarn("%s starts with cluster out of range(%u)\n",
718 					      fullpath(&dirent),
719 					      dirent.head);
720 				else if (fat[dirent.head].next == CLUST_FREE)
721 					pwarn("%s starts with free cluster\n",
722 					      fullpath(&dirent));
723 				else if (fat[dirent.head].next >= CLUST_RSRVD)
724 					pwarn("%s starts with cluster marked %s\n",
725 					      fullpath(&dirent),
726 					      rsrvdcltype(fat[dirent.head].next));
727 				else
728 					pwarn("%s doesn't start a cluster chain\n",
729 					      fullpath(&dirent));
730 				if (dirent.flags & ATTR_DIRECTORY) {
731 					if (ask(0, "Remove")) {
732 						*p = SLOT_DELETED;
733 						mod |= THISMOD|FSDIRMOD;
734 					} else
735 						mod |= FSERROR;
736 					continue;
737 				} else {
738 					if (ask(1, "Truncate")) {
739 						p[28] = p[29] = p[30] = p[31] = 0;
740 						p[26] = p[27] = 0;
741 						if (boot->ClustMask == CLUST32_MASK)
742 							p[20] = p[21] = 0;
743 						dirent.size = 0;
744 						mod |= THISMOD|FSDIRMOD;
745 					} else
746 						mod |= FSERROR;
747 				}
748 			}
749 
750 			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
751 				fat[dirent.head].flags |= FAT_USED;
752 
753 			if (dirent.flags & ATTR_DIRECTORY) {
754 				/*
755 				 * gather more info for directories
756 				 */
757 				struct dirTodoNode *n;
758 
759 				if (dirent.size) {
760 					pwarn("Directory %s has size != 0\n",
761 					      fullpath(&dirent));
762 					if (ask(1, "Correct")) {
763 						p[28] = p[29] = p[30] = p[31] = 0;
764 						dirent.size = 0;
765 						mod |= THISMOD|FSDIRMOD;
766 					} else
767 						mod |= FSERROR;
768 				}
769 				/*
770 				 * handle `.' and `..' specially
771 				 */
772 				if (strcmp(dirent.name, ".") == 0) {
773 					if (dirent.head != dir->head) {
774 						pwarn("`.' entry in %s has incorrect start cluster\n",
775 						      fullpath(dir));
776 						if (ask(1, "Correct")) {
777 							dirent.head = dir->head;
778 							p[26] = (u_char)dirent.head;
779 							p[27] = (u_char)(dirent.head >> 8);
780 							if (boot->ClustMask == CLUST32_MASK) {
781 								p[20] = (u_char)(dirent.head >> 16);
782 								p[21] = (u_char)(dirent.head >> 24);
783 							}
784 							mod |= THISMOD|FSDIRMOD;
785 						} else
786 							mod |= FSERROR;
787 					}
788 					continue;
789 				}
790 				if (strcmp(dirent.name, "..") == 0) {
791 					if (dir->parent) {		/* XXX */
792 						if (!dir->parent->parent) {
793 							if (dirent.head) {
794 								pwarn("`..' entry in %s has non-zero start cluster\n",
795 								      fullpath(dir));
796 								if (ask(1, "Correct")) {
797 									dirent.head = 0;
798 									p[26] = p[27] = 0;
799 									if (boot->ClustMask == CLUST32_MASK)
800 										p[20] = p[21] = 0;
801 									mod |= THISMOD|FSDIRMOD;
802 								} else
803 									mod |= FSERROR;
804 							}
805 						} else if (dirent.head != dir->parent->head) {
806 							pwarn("`..' entry in %s has incorrect start cluster\n",
807 							      fullpath(dir));
808 							if (ask(1, "Correct")) {
809 								dirent.head = dir->parent->head;
810 								p[26] = (u_char)dirent.head;
811 								p[27] = (u_char)(dirent.head >> 8);
812 								if (boot->ClustMask == CLUST32_MASK) {
813 									p[20] = (u_char)(dirent.head >> 16);
814 									p[21] = (u_char)(dirent.head >> 24);
815 								}
816 								mod |= THISMOD|FSDIRMOD;
817 							} else
818 								mod |= FSERROR;
819 						}
820 					}
821 					continue;
822 				}
823 
824 				/* create directory tree node */
825 				if (!(d = newDosDirEntry())) {
826 					perr("No space for directory");
827 					return FSFATAL;
828 				}
829 				memcpy(d, &dirent, sizeof(struct dosDirEntry));
830 				/* link it into the tree */
831 				dir->child = d;
832 
833 				/* Enter this directory into the todo list */
834 				if (!(n = newDirTodo())) {
835 					perr("No space for todo list");
836 					return FSFATAL;
837 				}
838 				n->next = pendingDirectories;
839 				n->dir = d;
840 				pendingDirectories = n;
841 			} else {
842 				mod |= k = checksize(boot, fat, p, &dirent);
843 				if (k & FSDIRMOD)
844 					mod |= THISMOD;
845 			}
846 			boot->NumFiles++;
847 		}
848 
849 		if (!(boot->flags & FAT32) && !dir->parent)
850 			break;
851 
852 		if (mod & THISMOD) {
853 			last *= 32;
854 			if (lseek(f, off, SEEK_SET) != off
855 			    || write(f, buffer, last) != last) {
856 				perr("Unable to write directory");
857 				return FSFATAL;
858 			}
859 			mod &= ~THISMOD;
860 		}
861 	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
862 	if (invlfn || vallfn)
863 		mod |= removede(f, boot, fat,
864 				invlfn ? invlfn : vallfn, p,
865 				invlfn ? invcl : valcl, -1, 0,
866 				fullpath(dir), 1);
867 
868 	/* The root directory of non fat32 filesystems is in a special
869 	 * area and may have been modified above without being written out.
870 	 */
871 	if ((mod & FSDIRMOD) && !(boot->flags & FAT32) && !dir->parent) {
872 		last *= 32;
873 		if (lseek(f, off, SEEK_SET) != off
874 		    || write(f, buffer, last) != last) {
875 			perr("Unable to write directory");
876 			return FSFATAL;
877 		}
878 		mod &= ~THISMOD;
879 	}
880 	return mod & ~THISMOD;
881 }
882 
883 int
884 handleDirTree(int dosfs, struct bootblock *boot, struct fatEntry *fat)
885 {
886 	int mod;
887 
888 	mod = readDosDirSection(dosfs, boot, fat, rootDir);
889 	if (mod & FSFATAL)
890 		return FSFATAL;
891 
892 	/*
893 	 * process the directory todo list
894 	 */
895 	while (pendingDirectories) {
896 		struct dosDirEntry *dir = pendingDirectories->dir;
897 		struct dirTodoNode *n = pendingDirectories->next;
898 
899 		/*
900 		 * remove TODO entry now, the list might change during
901 		 * directory reads
902 		 */
903 		freeDirTodo(pendingDirectories);
904 		pendingDirectories = n;
905 
906 		/*
907 		 * handle subdirectory
908 		 */
909 		mod |= readDosDirSection(dosfs, boot, fat, dir);
910 		if (mod & FSFATAL)
911 			return FSFATAL;
912 	}
913 
914 	return mod;
915 }
916 
917 /*
918  * Try to reconnect a FAT chain into dir
919  */
920 static u_char *lfbuf;
921 static cl_t lfcl;
922 static off_t lfoff;
923 
924 int
925 reconnect(int dosfs, struct bootblock *boot, struct fatEntry *fat, cl_t head)
926 {
927 	struct dosDirEntry d;
928 	int len;
929 	u_char *p;
930 
931 	if (!ask(1, "Reconnect"))
932 		return FSERROR;
933 
934 	if (!lostDir) {
935 		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
936 			if (!strcmp(lostDir->name, LOSTDIR))
937 				break;
938 		}
939 		if (!lostDir) {		/* Create LOSTDIR?		XXX */
940 			pwarn("No %s directory\n", LOSTDIR);
941 			return FSERROR;
942 		}
943 	}
944 	if (!lfbuf) {
945 		lfbuf = malloc(boot->ClusterSize);
946 		if (!lfbuf) {
947 			perr("No space for buffer");
948 			return FSFATAL;
949 		}
950 		p = NULL;
951 	} else
952 		p = lfbuf;
953 	while (1) {
954 		if (p)
955 			for (; p < lfbuf + boot->ClusterSize; p += 32)
956 				if (*p == SLOT_EMPTY
957 				    || *p == SLOT_DELETED)
958 					break;
959 		if (p && p < lfbuf + boot->ClusterSize)
960 			break;
961 		lfcl = p ? fat[lfcl].next : lostDir->head;
962 		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
963 			/* Extend LOSTDIR?				XXX */
964 			pwarn("No space in %s\n", LOSTDIR);
965 			return FSERROR;
966 		}
967 		lfoff = lfcl * boot->ClusterSize
968 		    + boot->ClusterOffset * boot->bpbBytesPerSec;
969 		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
970 		    || (size_t)read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
971 			perr("could not read LOST.DIR");
972 			return FSFATAL;
973 		}
974 		p = lfbuf;
975 	}
976 
977 	boot->NumFiles++;
978 	/* Ensure uniqueness of entry here!				XXX */
979 	memset(&d, 0, sizeof d);
980 	/* worst case -1 = 4294967295, 10 digits */
981 	len = snprintf(d.name, sizeof(d.name), "%u", head);
982 	d.flags = 0;
983 	d.head = head;
984 	d.size = fat[head].length * boot->ClusterSize;
985 
986 	memcpy(p, d.name, len);
987 	memset(p + len, ' ', 11 - len);
988 	memset(p + 11, 0, 32 - 11);
989 	p[26] = (u_char)d.head;
990 	p[27] = (u_char)(d.head >> 8);
991 	if (boot->ClustMask == CLUST32_MASK) {
992 		p[20] = (u_char)(d.head >> 16);
993 		p[21] = (u_char)(d.head >> 24);
994 	}
995 	p[28] = (u_char)d.size;
996 	p[29] = (u_char)(d.size >> 8);
997 	p[30] = (u_char)(d.size >> 16);
998 	p[31] = (u_char)(d.size >> 24);
999 	fat[head].flags |= FAT_USED;
1000 	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
1001 	    || (size_t)write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
1002 		perr("could not write LOST.DIR");
1003 		return FSFATAL;
1004 	}
1005 	return FSDIRMOD;
1006 }
1007 
1008 void
1009 finishlf(void)
1010 {
1011 	if (lfbuf)
1012 		free(lfbuf);
1013 	lfbuf = NULL;
1014 }
1015