xref: /freebsd/sbin/fsck_msdosfs/dir.c (revision 9a41926bfb664dd77659d1615ba55d75c2c530a8)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
5  * Copyright (c) 1995 Martin Husemann
6  * Some structure declaration borrowed from Paul Popelka
7  * (paulp@uts.amdahl.com), see /sys/msdosfs/ for reference.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 
31 #include <sys/cdefs.h>
32 #ifndef lint
33 __RCSID("$NetBSD: dir.c,v 1.20 2006/06/05 16:51:18 christos Exp $");
34 static const char rcsid[] =
35   "$FreeBSD$";
36 #endif /* not lint */
37 
38 #include <inttypes.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <ctype.h>
43 #include <unistd.h>
44 #include <time.h>
45 
46 #include <sys/param.h>
47 
48 #include "ext.h"
49 #include "fsutil.h"
50 
51 #define	SLOT_EMPTY	0x00		/* slot has never been used */
52 #define	SLOT_E5		0x05		/* the real value is 0xe5 */
53 #define	SLOT_DELETED	0xe5		/* file in this slot deleted */
54 
55 #define	ATTR_NORMAL	0x00		/* normal file */
56 #define	ATTR_READONLY	0x01		/* file is readonly */
57 #define	ATTR_HIDDEN	0x02		/* file is hidden */
58 #define	ATTR_SYSTEM	0x04		/* file is a system file */
59 #define	ATTR_VOLUME	0x08		/* entry is a volume label */
60 #define	ATTR_DIRECTORY	0x10		/* entry is a directory name */
61 #define	ATTR_ARCHIVE	0x20		/* file is new or modified */
62 
63 #define	ATTR_WIN95	0x0f		/* long name record */
64 
65 /*
66  * This is the format of the contents of the deTime field in the direntry
67  * structure.
68  * We don't use bitfields because we don't know how compilers for
69  * arbitrary machines will lay them out.
70  */
71 #define DT_2SECONDS_MASK	0x1F	/* seconds divided by 2 */
72 #define DT_2SECONDS_SHIFT	0
73 #define DT_MINUTES_MASK		0x7E0	/* minutes */
74 #define DT_MINUTES_SHIFT	5
75 #define DT_HOURS_MASK		0xF800	/* hours */
76 #define DT_HOURS_SHIFT		11
77 
78 /*
79  * This is the format of the contents of the deDate field in the direntry
80  * structure.
81  */
82 #define DD_DAY_MASK		0x1F	/* day of month */
83 #define DD_DAY_SHIFT		0
84 #define DD_MONTH_MASK		0x1E0	/* month */
85 #define DD_MONTH_SHIFT		5
86 #define DD_YEAR_MASK		0xFE00	/* year - 1980 */
87 #define DD_YEAR_SHIFT		9
88 
89 
90 /* dir.c */
91 static struct dosDirEntry *newDosDirEntry(void);
92 static void freeDosDirEntry(struct dosDirEntry *);
93 static struct dirTodoNode *newDirTodo(void);
94 static void freeDirTodo(struct dirTodoNode *);
95 static char *fullpath(struct dosDirEntry *);
96 static u_char calcShortSum(u_char *);
97 static int delete(int, struct bootblock *, struct fatEntry *, cl_t, int,
98     cl_t, int, int);
99 static int removede(int, struct bootblock *, struct fatEntry *, u_char *,
100     u_char *, cl_t, cl_t, cl_t, char *, int);
101 static int checksize(struct bootblock *, struct fatEntry *, u_char *,
102     struct dosDirEntry *);
103 static int readDosDirSection(int, struct bootblock *, struct fatEntry *,
104     struct dosDirEntry *);
105 
106 /*
107  * Manage free dosDirEntry structures.
108  */
109 static struct dosDirEntry *freede;
110 
111 static struct dosDirEntry *
112 newDosDirEntry(void)
113 {
114 	struct dosDirEntry *de;
115 
116 	if (!(de = freede)) {
117 		if (!(de = (struct dosDirEntry *)malloc(sizeof *de)))
118 			return 0;
119 	} else
120 		freede = de->next;
121 	return de;
122 }
123 
124 static void
125 freeDosDirEntry(struct dosDirEntry *de)
126 {
127 	de->next = freede;
128 	freede = de;
129 }
130 
131 /*
132  * The same for dirTodoNode structures.
133  */
134 static struct dirTodoNode *freedt;
135 
136 static struct dirTodoNode *
137 newDirTodo(void)
138 {
139 	struct dirTodoNode *dt;
140 
141 	if (!(dt = freedt)) {
142 		if (!(dt = (struct dirTodoNode *)malloc(sizeof *dt)))
143 			return 0;
144 	} else
145 		freedt = dt->next;
146 	return dt;
147 }
148 
149 static void
150 freeDirTodo(struct dirTodoNode *dt)
151 {
152 	dt->next = freedt;
153 	freedt = dt;
154 }
155 
156 /*
157  * The stack of unread directories
158  */
159 static struct dirTodoNode *pendingDirectories = NULL;
160 
161 /*
162  * Return the full pathname for a directory entry.
163  */
164 static char *
165 fullpath(struct dosDirEntry *dir)
166 {
167 	static char namebuf[MAXPATHLEN + 1];
168 	char *cp, *np;
169 	int nl;
170 
171 	cp = namebuf + sizeof namebuf - 1;
172 	*cp = '\0';
173 	do {
174 		np = dir->lname[0] ? dir->lname : dir->name;
175 		nl = strlen(np);
176 		if ((cp -= nl) <= namebuf + 1)
177 			break;
178 		memcpy(cp, np, nl);
179 		*--cp = '/';
180 	} while ((dir = dir->parent) != NULL);
181 	if (dir)
182 		*--cp = '?';
183 	else
184 		cp++;
185 	return cp;
186 }
187 
188 /*
189  * Calculate a checksum over an 8.3 alias name
190  */
191 static u_char
192 calcShortSum(u_char *p)
193 {
194 	u_char sum = 0;
195 	int i;
196 
197 	for (i = 0; i < 11; i++) {
198 		sum = (sum << 7)|(sum >> 1);	/* rotate right */
199 		sum += p[i];
200 	}
201 
202 	return sum;
203 }
204 
205 /*
206  * Global variables temporarily used during a directory scan
207  */
208 static char longName[DOSLONGNAMELEN] = "";
209 static u_char *buffer = NULL;
210 static u_char *delbuf = NULL;
211 
212 static struct dosDirEntry *rootDir;
213 static struct dosDirEntry *lostDir;
214 
215 /*
216  * Init internal state for a new directory scan.
217  */
218 int
219 resetDosDirSection(struct bootblock *boot, struct fatEntry *fat)
220 {
221 	int b1, b2;
222 	cl_t cl;
223 	int ret = FSOK;
224 	size_t len;
225 
226 	b1 = boot->bpbRootDirEnts * 32;
227 	b2 = boot->bpbSecPerClust * boot->bpbBytesPerSec;
228 
229 	if ((buffer = malloc(len = MAX(b1, b2))) == NULL) {
230 		perr("No space for directory buffer (%zu)", len);
231 		return FSFATAL;
232 	}
233 
234 	if ((delbuf = malloc(len = b2)) == NULL) {
235 		free(buffer);
236 		perr("No space for directory delbuf (%zu)", len);
237 		return FSFATAL;
238 	}
239 
240 	if ((rootDir = newDosDirEntry()) == NULL) {
241 		free(buffer);
242 		free(delbuf);
243 		perr("No space for directory entry");
244 		return FSFATAL;
245 	}
246 
247 	memset(rootDir, 0, sizeof *rootDir);
248 	if (boot->flags & FAT32) {
249 		if (boot->bpbRootClust < CLUST_FIRST ||
250 		    boot->bpbRootClust >= boot->NumClusters) {
251 			pfatal("Root directory starts with cluster out of range(%u)",
252 			       boot->bpbRootClust);
253 			return FSFATAL;
254 		}
255 		cl = fat[boot->bpbRootClust].next;
256 		if (cl < CLUST_FIRST
257 		    || (cl >= CLUST_RSRVD && cl< CLUST_EOFS)
258 		    || fat[boot->bpbRootClust].head != boot->bpbRootClust) {
259 			if (cl == CLUST_FREE)
260 				pwarn("Root directory starts with free cluster\n");
261 			else if (cl >= CLUST_RSRVD)
262 				pwarn("Root directory starts with cluster marked %s\n",
263 				      rsrvdcltype(cl));
264 			else {
265 				pfatal("Root directory doesn't start a cluster chain");
266 				return FSFATAL;
267 			}
268 			if (ask(1, "Fix")) {
269 				fat[boot->bpbRootClust].next = CLUST_FREE;
270 				ret = FSFATMOD;
271 			} else
272 				ret = FSFATAL;
273 		}
274 
275 		fat[boot->bpbRootClust].flags |= FAT_USED;
276 		rootDir->head = boot->bpbRootClust;
277 	}
278 
279 	return ret;
280 }
281 
282 /*
283  * Cleanup after a directory scan
284  */
285 void
286 finishDosDirSection(void)
287 {
288 	struct dirTodoNode *p, *np;
289 	struct dosDirEntry *d, *nd;
290 
291 	for (p = pendingDirectories; p; p = np) {
292 		np = p->next;
293 		freeDirTodo(p);
294 	}
295 	pendingDirectories = NULL;
296 	for (d = rootDir; d; d = nd) {
297 		if ((nd = d->child) != NULL) {
298 			d->child = 0;
299 			continue;
300 		}
301 		if (!(nd = d->next))
302 			nd = d->parent;
303 		freeDosDirEntry(d);
304 	}
305 	rootDir = lostDir = NULL;
306 	free(buffer);
307 	free(delbuf);
308 	buffer = NULL;
309 	delbuf = NULL;
310 }
311 
312 /*
313  * Delete directory entries between startcl, startoff and endcl, endoff.
314  */
315 static int
316 delete(int f, struct bootblock *boot, struct fatEntry *fat, cl_t startcl,
317     int startoff, cl_t endcl, int endoff, int notlast)
318 {
319 	u_char *s, *e;
320 	off_t off;
321 	int clsz = boot->bpbSecPerClust * boot->bpbBytesPerSec;
322 
323 	s = delbuf + startoff;
324 	e = delbuf + clsz;
325 	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
326 		if (startcl == endcl) {
327 			if (notlast)
328 				break;
329 			e = delbuf + endoff;
330 		}
331 		off = startcl * boot->bpbSecPerClust + boot->ClusterOffset;
332 		off *= boot->bpbBytesPerSec;
333 		if (lseek(f, off, SEEK_SET) != off) {
334 			perr("Unable to lseek to %" PRId64, off);
335 			return FSFATAL;
336 		}
337 		if (read(f, delbuf, clsz) != clsz) {
338 			perr("Unable to read directory");
339 			return FSFATAL;
340 		}
341 		while (s < e) {
342 			*s = SLOT_DELETED;
343 			s += 32;
344 		}
345 		if (lseek(f, off, SEEK_SET) != off) {
346 			perr("Unable to lseek to %" PRId64, off);
347 			return FSFATAL;
348 		}
349 		if (write(f, delbuf, clsz) != clsz) {
350 			perr("Unable to write directory");
351 			return FSFATAL;
352 		}
353 		if (startcl == endcl)
354 			break;
355 		startcl = fat[startcl].next;
356 		s = delbuf;
357 	}
358 	return FSOK;
359 }
360 
361 static int
362 removede(int f, struct bootblock *boot, struct fatEntry *fat, u_char *start,
363     u_char *end, cl_t startcl, cl_t endcl, cl_t curcl, char *path, int type)
364 {
365 	switch (type) {
366 	case 0:
367 		pwarn("Invalid long filename entry for %s\n", path);
368 		break;
369 	case 1:
370 		pwarn("Invalid long filename entry at end of directory %s\n",
371 		    path);
372 		break;
373 	case 2:
374 		pwarn("Invalid long filename entry for volume label\n");
375 		break;
376 	}
377 	if (ask(0, "Remove")) {
378 		if (startcl != curcl) {
379 			if (delete(f, boot, fat,
380 				   startcl, start - buffer,
381 				   endcl, end - buffer,
382 				   endcl == curcl) == FSFATAL)
383 				return FSFATAL;
384 			start = buffer;
385 		}
386 		/* startcl is < CLUST_FIRST for !fat32 root */
387 		if ((endcl == curcl) || (startcl < CLUST_FIRST))
388 			for (; start < end; start += 32)
389 				*start = SLOT_DELETED;
390 		return FSDIRMOD;
391 	}
392 	return FSERROR;
393 }
394 
395 /*
396  * Check an in-memory file entry
397  */
398 static int
399 checksize(struct bootblock *boot, struct fatEntry *fat, u_char *p,
400     struct dosDirEntry *dir)
401 {
402 	/*
403 	 * Check size on ordinary files
404 	 */
405 	u_int32_t physicalSize;
406 
407 	if (dir->head == CLUST_FREE)
408 		physicalSize = 0;
409 	else {
410 		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
411 			return FSERROR;
412 		physicalSize = fat[dir->head].length * boot->ClusterSize;
413 	}
414 	if (physicalSize < dir->size) {
415 		pwarn("size of %s is %u, should at most be %u\n",
416 		      fullpath(dir), dir->size, physicalSize);
417 		if (ask(1, "Truncate")) {
418 			dir->size = physicalSize;
419 			p[28] = (u_char)physicalSize;
420 			p[29] = (u_char)(physicalSize >> 8);
421 			p[30] = (u_char)(physicalSize >> 16);
422 			p[31] = (u_char)(physicalSize >> 24);
423 			return FSDIRMOD;
424 		} else
425 			return FSERROR;
426 	} else if (physicalSize - dir->size >= boot->ClusterSize) {
427 		pwarn("%s has too many clusters allocated\n",
428 		      fullpath(dir));
429 		if (ask(1, "Drop superfluous clusters")) {
430 			cl_t cl;
431 			u_int32_t sz, len;
432 
433 			for (cl = dir->head, len = sz = 0;
434 			    (sz += boot->ClusterSize) < dir->size; len++)
435 				cl = fat[cl].next;
436 			clearchain(boot, fat, fat[cl].next);
437 			fat[cl].next = CLUST_EOF;
438 			fat[dir->head].length = len;
439 			return FSFATMOD;
440 		} else
441 			return FSERROR;
442 	}
443 	return FSOK;
444 }
445 
446 /*
447  * Read a directory and
448  *   - resolve long name records
449  *   - enter file and directory records into the parent's list
450  *   - push directories onto the todo-stack
451  */
452 static int
453 readDosDirSection(int f, struct bootblock *boot, struct fatEntry *fat,
454     struct dosDirEntry *dir)
455 {
456 	struct dosDirEntry dirent, *d;
457 	u_char *p, *vallfn, *invlfn, *empty;
458 	off_t off;
459 	int i, j, k, last;
460 	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
461 	char *t;
462 	u_int lidx = 0;
463 	int shortSum;
464 	int mod = FSOK;
465 #define	THISMOD	0x8000			/* Only used within this routine */
466 
467 	cl = dir->head;
468 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
469 		/*
470 		 * Already handled somewhere else.
471 		 */
472 		return FSOK;
473 	}
474 	shortSum = -1;
475 	vallfn = invlfn = empty = NULL;
476 	do {
477 		if (!(boot->flags & FAT32) && !dir->parent) {
478 			last = boot->bpbRootDirEnts * 32;
479 			off = boot->bpbResSectors + boot->bpbFATs *
480 			    boot->FATsecs;
481 		} else {
482 			last = boot->bpbSecPerClust * boot->bpbBytesPerSec;
483 			off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
484 		}
485 
486 		off *= boot->bpbBytesPerSec;
487 		if (lseek(f, off, SEEK_SET) != off
488 		    || read(f, buffer, last) != last) {
489 			perr("Unable to read directory");
490 			return FSFATAL;
491 		}
492 		last /= 32;
493 		/*
494 		 * Check `.' and `..' entries here?			XXX
495 		 */
496 		for (p = buffer, i = 0; i < last; i++, p += 32) {
497 			if (dir->fsckflags & DIREMPWARN) {
498 				*p = SLOT_EMPTY;
499 				continue;
500 			}
501 
502 			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
503 				if (*p == SLOT_EMPTY) {
504 					dir->fsckflags |= DIREMPTY;
505 					empty = p;
506 					empcl = cl;
507 				}
508 				continue;
509 			}
510 
511 			if (dir->fsckflags & DIREMPTY) {
512 				if (!(dir->fsckflags & DIREMPWARN)) {
513 					pwarn("%s has entries after end of directory\n",
514 					      fullpath(dir));
515 					if (ask(1, "Extend")) {
516 						u_char *q;
517 
518 						dir->fsckflags &= ~DIREMPTY;
519 						if (delete(f, boot, fat,
520 							   empcl, empty - buffer,
521 							   cl, p - buffer, 1) == FSFATAL)
522 							return FSFATAL;
523 						q = empcl == cl ? empty : buffer;
524 						for (; q < p; q += 32)
525 							*q = SLOT_DELETED;
526 						mod |= THISMOD|FSDIRMOD;
527 					} else if (ask(0, "Truncate"))
528 						dir->fsckflags |= DIREMPWARN;
529 				}
530 				if (dir->fsckflags & DIREMPWARN) {
531 					*p = SLOT_DELETED;
532 					mod |= THISMOD|FSDIRMOD;
533 					continue;
534 				} else if (dir->fsckflags & DIREMPTY)
535 					mod |= FSERROR;
536 				empty = NULL;
537 			}
538 
539 			if (p[11] == ATTR_WIN95) {
540 				if (*p & LRFIRST) {
541 					if (shortSum != -1) {
542 						if (!invlfn) {
543 							invlfn = vallfn;
544 							invcl = valcl;
545 						}
546 					}
547 					memset(longName, 0, sizeof longName);
548 					shortSum = p[13];
549 					vallfn = p;
550 					valcl = cl;
551 				} else if (shortSum != p[13]
552 					   || lidx != (*p & LRNOMASK)) {
553 					if (!invlfn) {
554 						invlfn = vallfn;
555 						invcl = valcl;
556 					}
557 					if (!invlfn) {
558 						invlfn = p;
559 						invcl = cl;
560 					}
561 					vallfn = NULL;
562 				}
563 				lidx = *p & LRNOMASK;
564 				t = longName + --lidx * 13;
565 				for (k = 1; k < 11 && t < longName +
566 				    sizeof(longName); k += 2) {
567 					if (!p[k] && !p[k + 1])
568 						break;
569 					*t++ = p[k];
570 					/*
571 					 * Warn about those unusable chars in msdosfs here?	XXX
572 					 */
573 					if (p[k + 1])
574 						t[-1] = '?';
575 				}
576 				if (k >= 11)
577 					for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
578 						if (!p[k] && !p[k + 1])
579 							break;
580 						*t++ = p[k];
581 						if (p[k + 1])
582 							t[-1] = '?';
583 					}
584 				if (k >= 26)
585 					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
586 						if (!p[k] && !p[k + 1])
587 							break;
588 						*t++ = p[k];
589 						if (p[k + 1])
590 							t[-1] = '?';
591 					}
592 				if (t >= longName + sizeof(longName)) {
593 					pwarn("long filename too long\n");
594 					if (!invlfn) {
595 						invlfn = vallfn;
596 						invcl = valcl;
597 					}
598 					vallfn = NULL;
599 				}
600 				if (p[26] | (p[27] << 8)) {
601 					pwarn("long filename record cluster start != 0\n");
602 					if (!invlfn) {
603 						invlfn = vallfn;
604 						invcl = cl;
605 					}
606 					vallfn = NULL;
607 				}
608 				continue;	/* long records don't carry further
609 						 * information */
610 			}
611 
612 			/*
613 			 * This is a standard msdosfs directory entry.
614 			 */
615 			memset(&dirent, 0, sizeof dirent);
616 
617 			/*
618 			 * it's a short name record, but we need to know
619 			 * more, so get the flags first.
620 			 */
621 			dirent.flags = p[11];
622 
623 			/*
624 			 * Translate from 850 to ISO here		XXX
625 			 */
626 			for (j = 0; j < 8; j++)
627 				dirent.name[j] = p[j];
628 			dirent.name[8] = '\0';
629 			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
630 				dirent.name[k] = '\0';
631 			if (k < 0 || dirent.name[k] != '\0')
632 				k++;
633 			if (dirent.name[0] == SLOT_E5)
634 				dirent.name[0] = 0xe5;
635 
636 			if (dirent.flags & ATTR_VOLUME) {
637 				if (vallfn || invlfn) {
638 					mod |= removede(f, boot, fat,
639 							invlfn ? invlfn : vallfn, p,
640 							invlfn ? invcl : valcl, -1, 0,
641 							fullpath(dir), 2);
642 					vallfn = NULL;
643 					invlfn = NULL;
644 				}
645 				continue;
646 			}
647 
648 			if (p[8] != ' ')
649 				dirent.name[k++] = '.';
650 			for (j = 0; j < 3; j++)
651 				dirent.name[k++] = p[j+8];
652 			dirent.name[k] = '\0';
653 			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
654 				dirent.name[k] = '\0';
655 
656 			if (vallfn && shortSum != calcShortSum(p)) {
657 				if (!invlfn) {
658 					invlfn = vallfn;
659 					invcl = valcl;
660 				}
661 				vallfn = NULL;
662 			}
663 			dirent.head = p[26] | (p[27] << 8);
664 			if (boot->ClustMask == CLUST32_MASK)
665 				dirent.head |= (p[20] << 16) | (p[21] << 24);
666 			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
667 			if (vallfn) {
668 				strlcpy(dirent.lname, longName,
669 				    sizeof(dirent.lname));
670 				longName[0] = '\0';
671 				shortSum = -1;
672 			}
673 
674 			dirent.parent = dir;
675 			dirent.next = dir->child;
676 
677 			if (invlfn) {
678 				mod |= k = removede(f, boot, fat,
679 						    invlfn, vallfn ? vallfn : p,
680 						    invcl, vallfn ? valcl : cl, cl,
681 						    fullpath(&dirent), 0);
682 				if (mod & FSFATAL)
683 					return FSFATAL;
684 				if (vallfn
685 				    ? (valcl == cl && vallfn != buffer)
686 				    : p != buffer)
687 					if (k & FSDIRMOD)
688 						mod |= THISMOD;
689 			}
690 
691 			vallfn = NULL; /* not used any longer */
692 			invlfn = NULL;
693 
694 			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
695 				if (dirent.head != 0) {
696 					pwarn("%s has clusters, but size 0\n",
697 					      fullpath(&dirent));
698 					if (ask(1, "Drop allocated clusters")) {
699 						p[26] = p[27] = 0;
700 						if (boot->ClustMask == CLUST32_MASK)
701 							p[20] = p[21] = 0;
702 						clearchain(boot, fat, dirent.head);
703 						dirent.head = 0;
704 						mod |= THISMOD|FSDIRMOD|FSFATMOD;
705 					} else
706 						mod |= FSERROR;
707 				}
708 			} else if (dirent.head == 0
709 				   && !strcmp(dirent.name, "..")
710 				   && dir->parent			/* XXX */
711 				   && !dir->parent->parent) {
712 				/*
713 				 *  Do nothing, the parent is the root
714 				 */
715 			} else if (dirent.head < CLUST_FIRST
716 				   || dirent.head >= boot->NumClusters
717 				   || fat[dirent.head].next == CLUST_FREE
718 				   || (fat[dirent.head].next >= CLUST_RSRVD
719 				       && fat[dirent.head].next < CLUST_EOFS)
720 				   || fat[dirent.head].head != dirent.head) {
721 				if (dirent.head == 0)
722 					pwarn("%s has no clusters\n",
723 					      fullpath(&dirent));
724 				else if (dirent.head < CLUST_FIRST
725 					 || dirent.head >= boot->NumClusters)
726 					pwarn("%s starts with cluster out of range(%u)\n",
727 					      fullpath(&dirent),
728 					      dirent.head);
729 				else if (fat[dirent.head].next == CLUST_FREE)
730 					pwarn("%s starts with free cluster\n",
731 					      fullpath(&dirent));
732 				else if (fat[dirent.head].next >= CLUST_RSRVD)
733 					pwarn("%s starts with cluster marked %s\n",
734 					      fullpath(&dirent),
735 					      rsrvdcltype(fat[dirent.head].next));
736 				else
737 					pwarn("%s doesn't start a cluster chain\n",
738 					      fullpath(&dirent));
739 				if (dirent.flags & ATTR_DIRECTORY) {
740 					if (ask(0, "Remove")) {
741 						*p = SLOT_DELETED;
742 						mod |= THISMOD|FSDIRMOD;
743 					} else
744 						mod |= FSERROR;
745 					continue;
746 				} else {
747 					if (ask(1, "Truncate")) {
748 						p[28] = p[29] = p[30] = p[31] = 0;
749 						p[26] = p[27] = 0;
750 						if (boot->ClustMask == CLUST32_MASK)
751 							p[20] = p[21] = 0;
752 						dirent.size = 0;
753 						mod |= THISMOD|FSDIRMOD;
754 					} else
755 						mod |= FSERROR;
756 				}
757 			}
758 
759 			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
760 				fat[dirent.head].flags |= FAT_USED;
761 
762 			if (dirent.flags & ATTR_DIRECTORY) {
763 				/*
764 				 * gather more info for directories
765 				 */
766 				struct dirTodoNode *n;
767 
768 				if (dirent.size) {
769 					pwarn("Directory %s has size != 0\n",
770 					      fullpath(&dirent));
771 					if (ask(1, "Correct")) {
772 						p[28] = p[29] = p[30] = p[31] = 0;
773 						dirent.size = 0;
774 						mod |= THISMOD|FSDIRMOD;
775 					} else
776 						mod |= FSERROR;
777 				}
778 				/*
779 				 * handle `.' and `..' specially
780 				 */
781 				if (strcmp(dirent.name, ".") == 0) {
782 					if (dirent.head != dir->head) {
783 						pwarn("`.' entry in %s has incorrect start cluster\n",
784 						      fullpath(dir));
785 						if (ask(1, "Correct")) {
786 							dirent.head = dir->head;
787 							p[26] = (u_char)dirent.head;
788 							p[27] = (u_char)(dirent.head >> 8);
789 							if (boot->ClustMask == CLUST32_MASK) {
790 								p[20] = (u_char)(dirent.head >> 16);
791 								p[21] = (u_char)(dirent.head >> 24);
792 							}
793 							mod |= THISMOD|FSDIRMOD;
794 						} else
795 							mod |= FSERROR;
796 					}
797 					continue;
798 				}
799 				if (strcmp(dirent.name, "..") == 0) {
800 					if (dir->parent) {		/* XXX */
801 						if (!dir->parent->parent) {
802 							if (dirent.head) {
803 								pwarn("`..' entry in %s has non-zero start cluster\n",
804 								      fullpath(dir));
805 								if (ask(1, "Correct")) {
806 									dirent.head = 0;
807 									p[26] = p[27] = 0;
808 									if (boot->ClustMask == CLUST32_MASK)
809 										p[20] = p[21] = 0;
810 									mod |= THISMOD|FSDIRMOD;
811 								} else
812 									mod |= FSERROR;
813 							}
814 						} else if (dirent.head != dir->parent->head) {
815 							pwarn("`..' entry in %s has incorrect start cluster\n",
816 							      fullpath(dir));
817 							if (ask(1, "Correct")) {
818 								dirent.head = dir->parent->head;
819 								p[26] = (u_char)dirent.head;
820 								p[27] = (u_char)(dirent.head >> 8);
821 								if (boot->ClustMask == CLUST32_MASK) {
822 									p[20] = (u_char)(dirent.head >> 16);
823 									p[21] = (u_char)(dirent.head >> 24);
824 								}
825 								mod |= THISMOD|FSDIRMOD;
826 							} else
827 								mod |= FSERROR;
828 						}
829 					}
830 					continue;
831 				}
832 
833 				/* create directory tree node */
834 				if (!(d = newDosDirEntry())) {
835 					perr("No space for directory");
836 					return FSFATAL;
837 				}
838 				memcpy(d, &dirent, sizeof(struct dosDirEntry));
839 				/* link it into the tree */
840 				dir->child = d;
841 
842 				/* Enter this directory into the todo list */
843 				if (!(n = newDirTodo())) {
844 					perr("No space for todo list");
845 					return FSFATAL;
846 				}
847 				n->next = pendingDirectories;
848 				n->dir = d;
849 				pendingDirectories = n;
850 			} else {
851 				mod |= k = checksize(boot, fat, p, &dirent);
852 				if (k & FSDIRMOD)
853 					mod |= THISMOD;
854 			}
855 			boot->NumFiles++;
856 		}
857 
858 		if (!(boot->flags & FAT32) && !dir->parent)
859 			break;
860 
861 		if (mod & THISMOD) {
862 			last *= 32;
863 			if (lseek(f, off, SEEK_SET) != off
864 			    || write(f, buffer, last) != last) {
865 				perr("Unable to write directory");
866 				return FSFATAL;
867 			}
868 			mod &= ~THISMOD;
869 		}
870 	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
871 	if (invlfn || vallfn)
872 		mod |= removede(f, boot, fat,
873 				invlfn ? invlfn : vallfn, p,
874 				invlfn ? invcl : valcl, -1, 0,
875 				fullpath(dir), 1);
876 
877 	/* The root directory of non fat32 filesystems is in a special
878 	 * area and may have been modified above without being written out.
879 	 */
880 	if ((mod & FSDIRMOD) && !(boot->flags & FAT32) && !dir->parent) {
881 		last *= 32;
882 		if (lseek(f, off, SEEK_SET) != off
883 		    || write(f, buffer, last) != last) {
884 			perr("Unable to write directory");
885 			return FSFATAL;
886 		}
887 		mod &= ~THISMOD;
888 	}
889 	return mod & ~THISMOD;
890 }
891 
892 int
893 handleDirTree(int dosfs, struct bootblock *boot, struct fatEntry *fat)
894 {
895 	int mod;
896 
897 	mod = readDosDirSection(dosfs, boot, fat, rootDir);
898 	if (mod & FSFATAL)
899 		return FSFATAL;
900 
901 	/*
902 	 * process the directory todo list
903 	 */
904 	while (pendingDirectories) {
905 		struct dosDirEntry *dir = pendingDirectories->dir;
906 		struct dirTodoNode *n = pendingDirectories->next;
907 
908 		/*
909 		 * remove TODO entry now, the list might change during
910 		 * directory reads
911 		 */
912 		freeDirTodo(pendingDirectories);
913 		pendingDirectories = n;
914 
915 		/*
916 		 * handle subdirectory
917 		 */
918 		mod |= readDosDirSection(dosfs, boot, fat, dir);
919 		if (mod & FSFATAL)
920 			return FSFATAL;
921 	}
922 
923 	return mod;
924 }
925 
926 /*
927  * Try to reconnect a FAT chain into dir
928  */
929 static u_char *lfbuf;
930 static cl_t lfcl;
931 static off_t lfoff;
932 
933 int
934 reconnect(int dosfs, struct bootblock *boot, struct fatEntry *fat, cl_t head)
935 {
936 	struct dosDirEntry d;
937 	int len;
938 	u_char *p;
939 
940 	if (!ask(1, "Reconnect"))
941 		return FSERROR;
942 
943 	if (!lostDir) {
944 		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
945 			if (!strcmp(lostDir->name, LOSTDIR))
946 				break;
947 		}
948 		if (!lostDir) {		/* Create LOSTDIR?		XXX */
949 			pwarn("No %s directory\n", LOSTDIR);
950 			return FSERROR;
951 		}
952 	}
953 	if (!lfbuf) {
954 		lfbuf = malloc(boot->ClusterSize);
955 		if (!lfbuf) {
956 			perr("No space for buffer");
957 			return FSFATAL;
958 		}
959 		p = NULL;
960 	} else
961 		p = lfbuf;
962 	while (1) {
963 		if (p)
964 			for (; p < lfbuf + boot->ClusterSize; p += 32)
965 				if (*p == SLOT_EMPTY
966 				    || *p == SLOT_DELETED)
967 					break;
968 		if (p && p < lfbuf + boot->ClusterSize)
969 			break;
970 		lfcl = p ? fat[lfcl].next : lostDir->head;
971 		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
972 			/* Extend LOSTDIR?				XXX */
973 			pwarn("No space in %s\n", LOSTDIR);
974 			return FSERROR;
975 		}
976 		lfoff = lfcl * boot->ClusterSize
977 		    + boot->ClusterOffset * boot->bpbBytesPerSec;
978 		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
979 		    || (size_t)read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
980 			perr("could not read LOST.DIR");
981 			return FSFATAL;
982 		}
983 		p = lfbuf;
984 	}
985 
986 	boot->NumFiles++;
987 	/* Ensure uniqueness of entry here!				XXX */
988 	memset(&d, 0, sizeof d);
989 	/* worst case -1 = 4294967295, 10 digits */
990 	len = snprintf(d.name, sizeof(d.name), "%u", head);
991 	d.flags = 0;
992 	d.head = head;
993 	d.size = fat[head].length * boot->ClusterSize;
994 
995 	memcpy(p, d.name, len);
996 	memset(p + len, ' ', 11 - len);
997 	memset(p + 11, 0, 32 - 11);
998 	p[26] = (u_char)d.head;
999 	p[27] = (u_char)(d.head >> 8);
1000 	if (boot->ClustMask == CLUST32_MASK) {
1001 		p[20] = (u_char)(d.head >> 16);
1002 		p[21] = (u_char)(d.head >> 24);
1003 	}
1004 	p[28] = (u_char)d.size;
1005 	p[29] = (u_char)(d.size >> 8);
1006 	p[30] = (u_char)(d.size >> 16);
1007 	p[31] = (u_char)(d.size >> 24);
1008 	fat[head].flags |= FAT_USED;
1009 	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
1010 	    || (size_t)write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
1011 		perr("could not write LOST.DIR");
1012 		return FSFATAL;
1013 	}
1014 	return FSDIRMOD;
1015 }
1016 
1017 void
1018 finishlf(void)
1019 {
1020 	if (lfbuf)
1021 		free(lfbuf);
1022 	lfbuf = NULL;
1023 }
1024