xref: /freebsd/sbin/fsck_msdosfs/dir.c (revision aa64588d28258aef88cc33b8043112e8856948d0)
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 1.14 1998/08/25 19:18:15 ross 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 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 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 
222 	b1 = boot->bpbRootDirEnts * 32;
223 	b2 = boot->bpbSecPerClust * boot->bpbBytesPerSec;
224 
225 	if ((buffer = malloc( b1 > b2 ? b1 : b2)) == NULL) {
226 		perror("No space for directory buffer");
227 		return FSFATAL;
228 	}
229 
230 	if ((delbuf = malloc(b2)) == NULL) {
231 		free(buffer);
232 		perror("No space for directory delbuf");
233 		return FSFATAL;
234 	}
235 
236 	if ((rootDir = newDosDirEntry()) == NULL) {
237 		free(buffer);
238 		free(delbuf);
239 		perror("No space for directory entry");
240 		return FSFATAL;
241 	}
242 
243 	memset(rootDir, 0, sizeof *rootDir);
244 	if (boot->flags & FAT32) {
245 		if (boot->bpbRootClust < CLUST_FIRST || boot->bpbRootClust >= boot->NumClusters) {
246 			pfatal("Root directory starts with cluster out of range(%u)",
247 			       boot->bpbRootClust);
248 			return FSFATAL;
249 		}
250 		cl = fat[boot->bpbRootClust].next;
251 		if (cl < CLUST_FIRST
252 		    || (cl >= CLUST_RSRVD && cl< CLUST_EOFS)
253 		    || fat[boot->bpbRootClust].head != boot->bpbRootClust) {
254 			if (cl == CLUST_FREE)
255 				pwarn("Root directory starts with free cluster\n");
256 			else if (cl >= CLUST_RSRVD)
257 				pwarn("Root directory starts with cluster marked %s\n",
258 				      rsrvdcltype(cl));
259 			else {
260 				pfatal("Root directory doesn't start a cluster chain");
261 				return FSFATAL;
262 			}
263 			if (ask(1, "Fix")) {
264 				fat[boot->bpbRootClust].next = CLUST_FREE;
265 				ret = FSFATMOD;
266 			} else
267 				ret = FSFATAL;
268 		}
269 
270 		fat[boot->bpbRootClust].flags |= FAT_USED;
271 		rootDir->head = boot->bpbRootClust;
272 	}
273 
274 	return ret;
275 }
276 
277 /*
278  * Cleanup after a directory scan
279  */
280 void
281 finishDosDirSection(void)
282 {
283 	struct dirTodoNode *p, *np;
284 	struct dosDirEntry *d, *nd;
285 
286 	for (p = pendingDirectories; p; p = np) {
287 		np = p->next;
288 		freeDirTodo(p);
289 	}
290 	pendingDirectories = 0;
291 	for (d = rootDir; d; d = nd) {
292 		if ((nd = d->child) != NULL) {
293 			d->child = 0;
294 			continue;
295 		}
296 		if (!(nd = d->next))
297 			nd = d->parent;
298 		freeDosDirEntry(d);
299 	}
300 	rootDir = lostDir = NULL;
301 	free(buffer);
302 	free(delbuf);
303 	buffer = NULL;
304 	delbuf = NULL;
305 }
306 
307 /*
308  * Delete directory entries between startcl, startoff and endcl, endoff.
309  */
310 static int
311 delete(int f, struct bootblock *boot, struct fatEntry *fat, cl_t startcl,
312     int startoff, cl_t endcl, int endoff, int notlast)
313 {
314 	u_char *s, *e;
315 	off_t off;
316 	int clsz = boot->bpbSecPerClust * boot->bpbBytesPerSec;
317 
318 	s = delbuf + startoff;
319 	e = delbuf + clsz;
320 	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
321 		if (startcl == endcl) {
322 			if (notlast)
323 				break;
324 			e = delbuf + endoff;
325 		}
326 		off = startcl * boot->bpbSecPerClust + boot->ClusterOffset;
327 		off *= boot->bpbBytesPerSec;
328 		if (lseek(f, off, SEEK_SET) != off
329 		    || read(f, delbuf, clsz) != clsz) {
330 			perror("Unable to read directory");
331 			return FSFATAL;
332 		}
333 		while (s < e) {
334 			*s = SLOT_DELETED;
335 			s += 32;
336 		}
337 		if (lseek(f, off, SEEK_SET) != off
338 		    || write(f, delbuf, clsz) != clsz) {
339 			perror("Unable to write directory");
340 			return FSFATAL;
341 		}
342 		if (startcl == endcl)
343 			break;
344 		startcl = fat[startcl].next;
345 		s = delbuf;
346 	}
347 	return FSOK;
348 }
349 
350 static int
351 removede(int f, struct bootblock *boot, struct fatEntry *fat, u_char *start,
352     u_char *end, cl_t startcl, cl_t endcl, cl_t curcl, char *path, int type)
353 {
354 	switch (type) {
355 	case 0:
356 		pwarn("Invalid long filename entry for %s\n", path);
357 		break;
358 	case 1:
359 		pwarn("Invalid long filename entry at end of directory %s\n", path);
360 		break;
361 	case 2:
362 		pwarn("Invalid long filename entry for volume label\n");
363 		break;
364 	}
365 	if (ask(0, "Remove")) {
366 		if (startcl != curcl) {
367 			if (delete(f, boot, fat,
368 				   startcl, start - buffer,
369 				   endcl, end - buffer,
370 				   endcl == curcl) == FSFATAL)
371 				return FSFATAL;
372 			start = buffer;
373 		}
374 		/* startcl is < CLUST_FIRST for !fat32 root */
375 		if ((endcl == curcl) || (startcl < CLUST_FIRST))
376 			for (; start < end; start += 32)
377 				*start = SLOT_DELETED;
378 		return FSDIRMOD;
379 	}
380 	return FSERROR;
381 }
382 
383 /*
384  * Check an in-memory file entry
385  */
386 static int
387 checksize(struct bootblock *boot, struct fatEntry *fat, u_char *p,
388     struct dosDirEntry *dir)
389 {
390 	/*
391 	 * Check size on ordinary files
392 	 */
393 	u_int32_t physicalSize;
394 
395 	if (dir->head == CLUST_FREE)
396 		physicalSize = 0;
397 	else {
398 		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
399 			return FSERROR;
400 		physicalSize = fat[dir->head].length * boot->ClusterSize;
401 	}
402 	if (physicalSize < dir->size) {
403 		pwarn("size of %s is %u, should at most be %u\n",
404 		      fullpath(dir), dir->size, physicalSize);
405 		if (ask(1, "Truncate")) {
406 			dir->size = physicalSize;
407 			p[28] = (u_char)physicalSize;
408 			p[29] = (u_char)(physicalSize >> 8);
409 			p[30] = (u_char)(physicalSize >> 16);
410 			p[31] = (u_char)(physicalSize >> 24);
411 			return FSDIRMOD;
412 		} else
413 			return FSERROR;
414 	} else if (physicalSize - dir->size >= boot->ClusterSize) {
415 		pwarn("%s has too many clusters allocated\n",
416 		      fullpath(dir));
417 		if (ask(1, "Drop superfluous clusters")) {
418 			cl_t cl;
419 			u_int32_t sz = 0;
420 
421 			for (cl = dir->head; (sz += boot->ClusterSize) < dir->size;)
422 				cl = fat[cl].next;
423 			clearchain(boot, fat, fat[cl].next);
424 			fat[cl].next = CLUST_EOF;
425 			return FSFATMOD;
426 		} else
427 			return FSERROR;
428 	}
429 	return FSOK;
430 }
431 
432 /*
433  * Read a directory and
434  *   - resolve long name records
435  *   - enter file and directory records into the parent's list
436  *   - push directories onto the todo-stack
437  */
438 static int
439 readDosDirSection(int f, struct bootblock *boot, struct fatEntry *fat,
440     struct dosDirEntry *dir)
441 {
442 	struct dosDirEntry dirent, *d;
443 	u_char *p, *vallfn, *invlfn, *empty;
444 	off_t off;
445 	int i, j, k, last;
446 	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
447 	char *t;
448 	u_int lidx = 0;
449 	int shortSum;
450 	int mod = FSOK;
451 #define	THISMOD	0x8000			/* Only used within this routine */
452 
453 	cl = dir->head;
454 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
455 		/*
456 		 * Already handled somewhere else.
457 		 */
458 		return FSOK;
459 	}
460 	shortSum = -1;
461 	vallfn = invlfn = empty = NULL;
462 	do {
463 		if (!(boot->flags & FAT32) && !dir->parent) {
464 			last = boot->bpbRootDirEnts * 32;
465 			off = boot->bpbResSectors + boot->bpbFATs * boot->FATsecs;
466 		} else {
467 			last = boot->bpbSecPerClust * boot->bpbBytesPerSec;
468 			off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
469 		}
470 
471 		off *= boot->bpbBytesPerSec;
472 		if (lseek(f, off, SEEK_SET) != off
473 		    || read(f, buffer, last) != last) {
474 			perror("Unable to read directory");
475 			return FSFATAL;
476 		}
477 		last /= 32;
478 		/*
479 		 * Check `.' and `..' entries here?			XXX
480 		 */
481 		for (p = buffer, i = 0; i < last; i++, p += 32) {
482 			if (dir->fsckflags & DIREMPWARN) {
483 				*p = SLOT_EMPTY;
484 				continue;
485 			}
486 
487 			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
488 				if (*p == SLOT_EMPTY) {
489 					dir->fsckflags |= DIREMPTY;
490 					empty = p;
491 					empcl = cl;
492 				}
493 				continue;
494 			}
495 
496 			if (dir->fsckflags & DIREMPTY) {
497 				if (!(dir->fsckflags & DIREMPWARN)) {
498 					pwarn("%s has entries after end of directory\n",
499 					      fullpath(dir));
500 					if (ask(1, "Extend")) {
501 						u_char *q;
502 
503 						dir->fsckflags &= ~DIREMPTY;
504 						if (delete(f, boot, fat,
505 							   empcl, empty - buffer,
506 							   cl, p - buffer, 1) == FSFATAL)
507 							return FSFATAL;
508 						q = empcl == cl ? empty : buffer;
509 						for (; q < p; q += 32)
510 							*q = SLOT_DELETED;
511 						mod |= THISMOD|FSDIRMOD;
512 					} else if (ask(0, "Truncate"))
513 						dir->fsckflags |= DIREMPWARN;
514 				}
515 				if (dir->fsckflags & DIREMPWARN) {
516 					*p = SLOT_DELETED;
517 					mod |= THISMOD|FSDIRMOD;
518 					continue;
519 				} else if (dir->fsckflags & DIREMPTY)
520 					mod |= FSERROR;
521 				empty = NULL;
522 			}
523 
524 			if (p[11] == ATTR_WIN95) {
525 				if (*p & LRFIRST) {
526 					if (shortSum != -1) {
527 						if (!invlfn) {
528 							invlfn = vallfn;
529 							invcl = valcl;
530 						}
531 					}
532 					memset(longName, 0, sizeof longName);
533 					shortSum = p[13];
534 					vallfn = p;
535 					valcl = cl;
536 				} else if (shortSum != p[13]
537 					   || lidx != (*p & LRNOMASK)) {
538 					if (!invlfn) {
539 						invlfn = vallfn;
540 						invcl = valcl;
541 					}
542 					if (!invlfn) {
543 						invlfn = p;
544 						invcl = cl;
545 					}
546 					vallfn = NULL;
547 				}
548 				lidx = *p & LRNOMASK;
549 				t = longName + --lidx * 13;
550 				for (k = 1; k < 11 && t < longName + sizeof(longName); k += 2) {
551 					if (!p[k] && !p[k + 1])
552 						break;
553 					*t++ = p[k];
554 					/*
555 					 * Warn about those unusable chars in msdosfs here?	XXX
556 					 */
557 					if (p[k + 1])
558 						t[-1] = '?';
559 				}
560 				if (k >= 11)
561 					for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
562 						if (!p[k] && !p[k + 1])
563 							break;
564 						*t++ = p[k];
565 						if (p[k + 1])
566 							t[-1] = '?';
567 					}
568 				if (k >= 26)
569 					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
570 						if (!p[k] && !p[k + 1])
571 							break;
572 						*t++ = p[k];
573 						if (p[k + 1])
574 							t[-1] = '?';
575 					}
576 				if (t >= longName + sizeof(longName)) {
577 					pwarn("long filename too long\n");
578 					if (!invlfn) {
579 						invlfn = vallfn;
580 						invcl = valcl;
581 					}
582 					vallfn = NULL;
583 				}
584 				if (p[26] | (p[27] << 8)) {
585 					pwarn("long filename record cluster start != 0\n");
586 					if (!invlfn) {
587 						invlfn = vallfn;
588 						invcl = cl;
589 					}
590 					vallfn = NULL;
591 				}
592 				continue;	/* long records don't carry further
593 						 * information */
594 			}
595 
596 			/*
597 			 * This is a standard msdosfs directory entry.
598 			 */
599 			memset(&dirent, 0, sizeof dirent);
600 
601 			/*
602 			 * it's a short name record, but we need to know
603 			 * more, so get the flags first.
604 			 */
605 			dirent.flags = p[11];
606 
607 			/*
608 			 * Translate from 850 to ISO here		XXX
609 			 */
610 			for (j = 0; j < 8; j++)
611 				dirent.name[j] = p[j];
612 			dirent.name[8] = '\0';
613 			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
614 				dirent.name[k] = '\0';
615 			if (dirent.name[k] != '\0')
616 				k++;
617 			if (dirent.name[0] == SLOT_E5)
618 				dirent.name[0] = 0xe5;
619 
620 			if (dirent.flags & ATTR_VOLUME) {
621 				if (vallfn || invlfn) {
622 					mod |= removede(f, boot, fat,
623 							invlfn ? invlfn : vallfn, p,
624 							invlfn ? invcl : valcl, -1, 0,
625 							fullpath(dir), 2);
626 					vallfn = NULL;
627 					invlfn = NULL;
628 				}
629 				continue;
630 			}
631 
632 			if (p[8] != ' ')
633 				dirent.name[k++] = '.';
634 			for (j = 0; j < 3; j++)
635 				dirent.name[k++] = p[j+8];
636 			dirent.name[k] = '\0';
637 			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
638 				dirent.name[k] = '\0';
639 
640 			if (vallfn && shortSum != calcShortSum(p)) {
641 				if (!invlfn) {
642 					invlfn = vallfn;
643 					invcl = valcl;
644 				}
645 				vallfn = NULL;
646 			}
647 			dirent.head = p[26] | (p[27] << 8);
648 			if (boot->ClustMask == CLUST32_MASK)
649 				dirent.head |= (p[20] << 16) | (p[21] << 24);
650 			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
651 			if (vallfn) {
652 				strlcpy(dirent.lname, longName,
653 				    sizeof(dirent.lname));
654 				longName[0] = '\0';
655 				shortSum = -1;
656 			}
657 
658 			dirent.parent = dir;
659 			dirent.next = dir->child;
660 
661 			if (invlfn) {
662 				mod |= k = removede(f, boot, fat,
663 						    invlfn, vallfn ? vallfn : p,
664 						    invcl, vallfn ? valcl : cl, cl,
665 						    fullpath(&dirent), 0);
666 				if (mod & FSFATAL)
667 					return FSFATAL;
668 				if (vallfn
669 				    ? (valcl == cl && vallfn != buffer)
670 				    : p != buffer)
671 					if (k & FSDIRMOD)
672 						mod |= THISMOD;
673 			}
674 
675 			vallfn = NULL; /* not used any longer */
676 			invlfn = NULL;
677 
678 			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
679 				if (dirent.head != 0) {
680 					pwarn("%s has clusters, but size 0\n",
681 					      fullpath(&dirent));
682 					if (ask(1, "Drop allocated clusters")) {
683 						p[26] = p[27] = 0;
684 						if (boot->ClustMask == CLUST32_MASK)
685 							p[20] = p[21] = 0;
686 						clearchain(boot, fat, dirent.head);
687 						dirent.head = 0;
688 						mod |= THISMOD|FSDIRMOD|FSFATMOD;
689 					} else
690 						mod |= FSERROR;
691 				}
692 			} else if (dirent.head == 0
693 				   && !strcmp(dirent.name, "..")
694 				   && dir->parent			/* XXX */
695 				   && !dir->parent->parent) {
696 				/*
697 				 *  Do nothing, the parent is the root
698 				 */
699 			} else if (dirent.head < CLUST_FIRST
700 				   || dirent.head >= boot->NumClusters
701 				   || fat[dirent.head].next == CLUST_FREE
702 				   || (fat[dirent.head].next >= CLUST_RSRVD
703 				       && fat[dirent.head].next < CLUST_EOFS)
704 				   || fat[dirent.head].head != dirent.head) {
705 				if (dirent.head == 0)
706 					pwarn("%s has no clusters\n",
707 					      fullpath(&dirent));
708 				else if (dirent.head < CLUST_FIRST
709 					 || dirent.head >= boot->NumClusters)
710 					pwarn("%s starts with cluster out of range(%u)\n",
711 					      fullpath(&dirent),
712 					      dirent.head);
713 				else if (fat[dirent.head].next == CLUST_FREE)
714 					pwarn("%s starts with free cluster\n",
715 					      fullpath(&dirent));
716 				else if (fat[dirent.head].next >= CLUST_RSRVD)
717 					pwarn("%s starts with cluster marked %s\n",
718 					      fullpath(&dirent),
719 					      rsrvdcltype(fat[dirent.head].next));
720 				else
721 					pwarn("%s doesn't start a cluster chain\n",
722 					      fullpath(&dirent));
723 				if (dirent.flags & ATTR_DIRECTORY) {
724 					if (ask(0, "Remove")) {
725 						*p = SLOT_DELETED;
726 						mod |= THISMOD|FSDIRMOD;
727 					} else
728 						mod |= FSERROR;
729 					continue;
730 				} else {
731 					if (ask(1, "Truncate")) {
732 						p[28] = p[29] = p[30] = p[31] = 0;
733 						p[26] = p[27] = 0;
734 						if (boot->ClustMask == CLUST32_MASK)
735 							p[20] = p[21] = 0;
736 						dirent.size = 0;
737 						mod |= THISMOD|FSDIRMOD;
738 					} else
739 						mod |= FSERROR;
740 				}
741 			}
742 
743 			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
744 				fat[dirent.head].flags |= FAT_USED;
745 
746 			if (dirent.flags & ATTR_DIRECTORY) {
747 				/*
748 				 * gather more info for directories
749 				 */
750 				struct dirTodoNode *n;
751 
752 				if (dirent.size) {
753 					pwarn("Directory %s has size != 0\n",
754 					      fullpath(&dirent));
755 					if (ask(1, "Correct")) {
756 						p[28] = p[29] = p[30] = p[31] = 0;
757 						dirent.size = 0;
758 						mod |= THISMOD|FSDIRMOD;
759 					} else
760 						mod |= FSERROR;
761 				}
762 				/*
763 				 * handle `.' and `..' specially
764 				 */
765 				if (strcmp(dirent.name, ".") == 0) {
766 					if (dirent.head != dir->head) {
767 						pwarn("`.' entry in %s has incorrect start cluster\n",
768 						      fullpath(dir));
769 						if (ask(1, "Correct")) {
770 							dirent.head = dir->head;
771 							p[26] = (u_char)dirent.head;
772 							p[27] = (u_char)(dirent.head >> 8);
773 							if (boot->ClustMask == CLUST32_MASK) {
774 								p[20] = (u_char)(dirent.head >> 16);
775 								p[21] = (u_char)(dirent.head >> 24);
776 							}
777 							mod |= THISMOD|FSDIRMOD;
778 						} else
779 							mod |= FSERROR;
780 					}
781 					continue;
782 				}
783 				if (strcmp(dirent.name, "..") == 0) {
784 					if (dir->parent) {		/* XXX */
785 						if (!dir->parent->parent) {
786 							if (dirent.head) {
787 								pwarn("`..' entry in %s has non-zero start cluster\n",
788 								      fullpath(dir));
789 								if (ask(1, "Correct")) {
790 									dirent.head = 0;
791 									p[26] = p[27] = 0;
792 									if (boot->ClustMask == CLUST32_MASK)
793 										p[20] = p[21] = 0;
794 									mod |= THISMOD|FSDIRMOD;
795 								} else
796 									mod |= FSERROR;
797 							}
798 						} else if (dirent.head != dir->parent->head) {
799 							pwarn("`..' entry in %s has incorrect start cluster\n",
800 							      fullpath(dir));
801 							if (ask(1, "Correct")) {
802 								dirent.head = dir->parent->head;
803 								p[26] = (u_char)dirent.head;
804 								p[27] = (u_char)(dirent.head >> 8);
805 								if (boot->ClustMask == CLUST32_MASK) {
806 									p[20] = (u_char)(dirent.head >> 16);
807 									p[21] = (u_char)(dirent.head >> 24);
808 								}
809 								mod |= THISMOD|FSDIRMOD;
810 							} else
811 								mod |= FSERROR;
812 						}
813 					}
814 					continue;
815 				}
816 
817 				/* create directory tree node */
818 				if (!(d = newDosDirEntry())) {
819 					perror("No space for directory");
820 					return FSFATAL;
821 				}
822 				memcpy(d, &dirent, sizeof(struct dosDirEntry));
823 				/* link it into the tree */
824 				dir->child = d;
825 
826 				/* Enter this directory into the todo list */
827 				if (!(n = newDirTodo())) {
828 					perror("No space for todo list");
829 					return FSFATAL;
830 				}
831 				n->next = pendingDirectories;
832 				n->dir = d;
833 				pendingDirectories = n;
834 			} else {
835 				mod |= k = checksize(boot, fat, p, &dirent);
836 				if (k & FSDIRMOD)
837 					mod |= THISMOD;
838 			}
839 			boot->NumFiles++;
840 		}
841 
842 		if (!(boot->flags & FAT32) && !dir->parent)
843 			break;
844 
845 		if (mod & THISMOD) {
846 			last *= 32;
847 			if (lseek(f, off, SEEK_SET) != off
848 			    || write(f, buffer, last) != last) {
849 				perror("Unable to write directory");
850 				return FSFATAL;
851 			}
852 			mod &= ~THISMOD;
853 		}
854 	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
855 	if (invlfn || vallfn)
856 		mod |= removede(f, boot, fat,
857 				invlfn ? invlfn : vallfn, p,
858 				invlfn ? invcl : valcl, -1, 0,
859 				fullpath(dir), 1);
860 
861 	/* The root directory of non fat32 filesystems is in a special
862 	 * area and may have been modified above without being written out.
863 	 */
864 	if ((mod & FSDIRMOD) && !(boot->flags & FAT32) && !dir->parent) {
865 		last *= 32;
866 		if (lseek(f, off, SEEK_SET) != off
867 		    || write(f, buffer, last) != last) {
868 			perror("Unable to write directory");
869 			return FSFATAL;
870 		}
871 		mod &= ~THISMOD;
872 	}
873 	return mod & ~THISMOD;
874 }
875 
876 int
877 handleDirTree(int dosfs, struct bootblock *boot, struct fatEntry *fat)
878 {
879 	int mod;
880 
881 	mod = readDosDirSection(dosfs, boot, fat, rootDir);
882 	if (mod & FSFATAL)
883 		return FSFATAL;
884 
885 	/*
886 	 * process the directory todo list
887 	 */
888 	while (pendingDirectories) {
889 		struct dosDirEntry *dir = pendingDirectories->dir;
890 		struct dirTodoNode *n = pendingDirectories->next;
891 
892 		/*
893 		 * remove TODO entry now, the list might change during
894 		 * directory reads
895 		 */
896 		freeDirTodo(pendingDirectories);
897 		pendingDirectories = n;
898 
899 		/*
900 		 * handle subdirectory
901 		 */
902 		mod |= readDosDirSection(dosfs, boot, fat, dir);
903 		if (mod & FSFATAL)
904 			return FSFATAL;
905 	}
906 
907 	return mod;
908 }
909 
910 /*
911  * Try to reconnect a FAT chain into dir
912  */
913 static u_char *lfbuf;
914 static cl_t lfcl;
915 static off_t lfoff;
916 
917 int
918 reconnect(int dosfs, struct bootblock *boot, struct fatEntry *fat, cl_t head)
919 {
920 	struct dosDirEntry d;
921 	u_char *p;
922 
923 	if (!ask(1, "Reconnect"))
924 		return FSERROR;
925 
926 	if (!lostDir) {
927 		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
928 			if (!strcmp(lostDir->name, LOSTDIR))
929 				break;
930 		}
931 		if (!lostDir) {		/* Create LOSTDIR?		XXX */
932 			pwarn("No %s directory\n", LOSTDIR);
933 			return FSERROR;
934 		}
935 	}
936 	if (!lfbuf) {
937 		lfbuf = malloc(boot->ClusterSize);
938 		if (!lfbuf) {
939 			perror("No space for buffer");
940 			return FSFATAL;
941 		}
942 		p = NULL;
943 	} else
944 		p = lfbuf;
945 	while (1) {
946 		if (p)
947 			for (; p < lfbuf + boot->ClusterSize; p += 32)
948 				if (*p == SLOT_EMPTY
949 				    || *p == SLOT_DELETED)
950 					break;
951 		if (p && p < lfbuf + boot->ClusterSize)
952 			break;
953 		lfcl = p ? fat[lfcl].next : lostDir->head;
954 		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
955 			/* Extend LOSTDIR?				XXX */
956 			pwarn("No space in %s\n", LOSTDIR);
957 			return FSERROR;
958 		}
959 		lfoff = lfcl * boot->ClusterSize
960 		    + boot->ClusterOffset * boot->bpbBytesPerSec;
961 		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
962 		    || (size_t)read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
963 			perror("could not read LOST.DIR");
964 			return FSFATAL;
965 		}
966 		p = lfbuf;
967 	}
968 
969 	boot->NumFiles++;
970 	/* Ensure uniqueness of entry here!				XXX */
971 	memset(&d, 0, sizeof d);
972 	(void)snprintf(d.name, sizeof(d.name), "%u", head);
973 	d.flags = 0;
974 	d.head = head;
975 	d.size = fat[head].length * boot->ClusterSize;
976 
977 	memset(p, 0, 32);
978 	memset(p, ' ', 11);
979 	memcpy(p, d.name, strlen(d.name));
980 	p[26] = (u_char)d.head;
981 	p[27] = (u_char)(d.head >> 8);
982 	if (boot->ClustMask == CLUST32_MASK) {
983 		p[20] = (u_char)(d.head >> 16);
984 		p[21] = (u_char)(d.head >> 24);
985 	}
986 	p[28] = (u_char)d.size;
987 	p[29] = (u_char)(d.size >> 8);
988 	p[30] = (u_char)(d.size >> 16);
989 	p[31] = (u_char)(d.size >> 24);
990 	fat[head].flags |= FAT_USED;
991 	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
992 	    || (size_t)write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
993 		perror("could not write LOST.DIR");
994 		return FSFATAL;
995 	}
996 	return FSDIRMOD;
997 }
998 
999 void
1000 finishlf(void)
1001 {
1002 	if (lfbuf)
1003 		free(lfbuf);
1004 	lfbuf = NULL;
1005 }
1006