xref: /freebsd/sbin/fsck_msdosfs/dir.c (revision 2ef9ff7dd34a78a7890ba4d6de64da34d9c10942)
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 <assert.h>
39 #include <inttypes.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <ctype.h>
44 #include <unistd.h>
45 #include <time.h>
46 
47 #include <sys/param.h>
48 
49 #include "ext.h"
50 #include "fsutil.h"
51 
52 #define	SLOT_EMPTY	0x00		/* slot has never been used */
53 #define	SLOT_E5		0x05		/* the real value is 0xe5 */
54 #define	SLOT_DELETED	0xe5		/* file in this slot deleted */
55 
56 #define	ATTR_NORMAL	0x00		/* normal file */
57 #define	ATTR_READONLY	0x01		/* file is readonly */
58 #define	ATTR_HIDDEN	0x02		/* file is hidden */
59 #define	ATTR_SYSTEM	0x04		/* file is a system file */
60 #define	ATTR_VOLUME	0x08		/* entry is a volume label */
61 #define	ATTR_DIRECTORY	0x10		/* entry is a directory name */
62 #define	ATTR_ARCHIVE	0x20		/* file is new or modified */
63 
64 #define	ATTR_WIN95	0x0f		/* long name record */
65 
66 /*
67  * This is the format of the contents of the deTime field in the direntry
68  * structure.
69  * We don't use bitfields because we don't know how compilers for
70  * arbitrary machines will lay them out.
71  */
72 #define DT_2SECONDS_MASK	0x1F	/* seconds divided by 2 */
73 #define DT_2SECONDS_SHIFT	0
74 #define DT_MINUTES_MASK		0x7E0	/* minutes */
75 #define DT_MINUTES_SHIFT	5
76 #define DT_HOURS_MASK		0xF800	/* hours */
77 #define DT_HOURS_SHIFT		11
78 
79 /*
80  * This is the format of the contents of the deDate field in the direntry
81  * structure.
82  */
83 #define DD_DAY_MASK		0x1F	/* day of month */
84 #define DD_DAY_SHIFT		0
85 #define DD_MONTH_MASK		0x1E0	/* month */
86 #define DD_MONTH_SHIFT		5
87 #define DD_YEAR_MASK		0xFE00	/* year - 1980 */
88 #define DD_YEAR_SHIFT		9
89 
90 
91 /* dir.c */
92 static struct dosDirEntry *newDosDirEntry(void);
93 static void freeDosDirEntry(struct dosDirEntry *);
94 static struct dirTodoNode *newDirTodo(void);
95 static void freeDirTodo(struct dirTodoNode *);
96 static char *fullpath(struct dosDirEntry *);
97 static u_char calcShortSum(u_char *);
98 static int delete(int, struct bootblock *, struct fatEntry *, cl_t, int,
99     cl_t, int, int);
100 static int removede(int, struct bootblock *, struct fatEntry *, u_char *,
101     u_char *, cl_t, cl_t, cl_t, char *, int);
102 static int checksize(struct bootblock *, struct fatEntry *, u_char *,
103     struct dosDirEntry *);
104 static int readDosDirSection(int, struct bootblock *, struct fatEntry *,
105     struct dosDirEntry *);
106 
107 /*
108  * Manage free dosDirEntry structures.
109  */
110 static struct dosDirEntry *freede;
111 
112 static struct dosDirEntry *
113 newDosDirEntry(void)
114 {
115 	struct dosDirEntry *de;
116 
117 	if (!(de = freede)) {
118 		if (!(de = malloc(sizeof *de)))
119 			return 0;
120 	} else
121 		freede = de->next;
122 	return de;
123 }
124 
125 static void
126 freeDosDirEntry(struct dosDirEntry *de)
127 {
128 	de->next = freede;
129 	freede = de;
130 }
131 
132 /*
133  * The same for dirTodoNode structures.
134  */
135 static struct dirTodoNode *freedt;
136 
137 static struct dirTodoNode *
138 newDirTodo(void)
139 {
140 	struct dirTodoNode *dt;
141 
142 	if (!(dt = freedt)) {
143 		if (!(dt = malloc(sizeof *dt)))
144 			return 0;
145 	} else
146 		freedt = dt->next;
147 	return dt;
148 }
149 
150 static void
151 freeDirTodo(struct dirTodoNode *dt)
152 {
153 	dt->next = freedt;
154 	freedt = dt;
155 }
156 
157 /*
158  * The stack of unread directories
159  */
160 static struct dirTodoNode *pendingDirectories = NULL;
161 
162 /*
163  * Return the full pathname for a directory entry.
164  */
165 static char *
166 fullpath(struct dosDirEntry *dir)
167 {
168 	static char namebuf[MAXPATHLEN + 1];
169 	char *cp, *np;
170 	int nl;
171 
172 	cp = namebuf + sizeof namebuf - 1;
173 	*cp = '\0';
174 	do {
175 		np = dir->lname[0] ? dir->lname : dir->name;
176 		nl = strlen(np);
177 		if ((cp -= nl) <= namebuf + 1)
178 			break;
179 		memcpy(cp, np, nl);
180 		*--cp = '/';
181 	} while ((dir = dir->parent) != NULL);
182 	if (dir)
183 		*--cp = '?';
184 	else
185 		cp++;
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 static 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 	size_t len;
226 
227 	b1 = boot->bpbRootDirEnts * 32;
228 	b2 = boot->bpbSecPerClust * boot->bpbBytesPerSec;
229 
230 	if ((buffer = malloc(len = MAX(b1, b2))) == NULL) {
231 		perr("No space for directory buffer (%zu)", len);
232 		return FSFATAL;
233 	}
234 
235 	if ((delbuf = malloc(len = b2)) == NULL) {
236 		free(buffer);
237 		perr("No space for directory delbuf (%zu)", len);
238 		return FSFATAL;
239 	}
240 
241 	if ((rootDir = newDosDirEntry()) == NULL) {
242 		free(buffer);
243 		free(delbuf);
244 		perr("No space for directory entry");
245 		return FSFATAL;
246 	}
247 
248 	memset(rootDir, 0, sizeof *rootDir);
249 	if (boot->flags & FAT32) {
250 		if (boot->bpbRootClust < CLUST_FIRST ||
251 		    boot->bpbRootClust >= boot->NumClusters) {
252 			pfatal("Root directory starts with cluster out of range(%u)",
253 			       boot->bpbRootClust);
254 			return FSFATAL;
255 		}
256 		cl = fat[boot->bpbRootClust].next;
257 		if (cl < CLUST_FIRST
258 		    || (cl >= CLUST_RSRVD && cl< CLUST_EOFS)
259 		    || fat[boot->bpbRootClust].head != boot->bpbRootClust) {
260 			if (cl == CLUST_FREE)
261 				pwarn("Root directory starts with free cluster\n");
262 			else if (cl >= CLUST_RSRVD)
263 				pwarn("Root directory starts with cluster marked %s\n",
264 				      rsrvdcltype(cl));
265 			else {
266 				pfatal("Root directory doesn't start a cluster chain");
267 				return FSFATAL;
268 			}
269 			if (ask(1, "Fix")) {
270 				fat[boot->bpbRootClust].next = CLUST_FREE;
271 				ret = FSFATMOD;
272 			} else
273 				ret = FSFATAL;
274 		}
275 
276 		fat[boot->bpbRootClust].flags |= FAT_USED;
277 		rootDir->head = boot->bpbRootClust;
278 	}
279 
280 	return ret;
281 }
282 
283 /*
284  * Cleanup after a directory scan
285  */
286 void
287 finishDosDirSection(void)
288 {
289 	struct dirTodoNode *p, *np;
290 	struct dosDirEntry *d, *nd;
291 
292 	for (p = pendingDirectories; p; p = np) {
293 		np = p->next;
294 		freeDirTodo(p);
295 	}
296 	pendingDirectories = NULL;
297 	for (d = rootDir; d; d = nd) {
298 		if ((nd = d->child) != NULL) {
299 			d->child = 0;
300 			continue;
301 		}
302 		if (!(nd = d->next))
303 			nd = d->parent;
304 		freeDosDirEntry(d);
305 	}
306 	rootDir = lostDir = NULL;
307 	free(buffer);
308 	free(delbuf);
309 	buffer = NULL;
310 	delbuf = NULL;
311 }
312 
313 /*
314  * Delete directory entries between startcl, startoff and endcl, endoff.
315  */
316 static int
317 delete(int f, struct bootblock *boot, struct fatEntry *fat, cl_t startcl,
318     int startoff, cl_t endcl, int endoff, int notlast)
319 {
320 	u_char *s, *e;
321 	off_t off;
322 	int clsz = boot->bpbSecPerClust * boot->bpbBytesPerSec;
323 
324 	s = delbuf + startoff;
325 	e = delbuf + clsz;
326 	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
327 		if (startcl == endcl) {
328 			if (notlast)
329 				break;
330 			e = delbuf + endoff;
331 		}
332 		off = startcl * boot->bpbSecPerClust + boot->ClusterOffset;
333 		off *= boot->bpbBytesPerSec;
334 		if (lseek(f, off, SEEK_SET) != off) {
335 			perr("Unable to lseek to %" PRId64, off);
336 			return FSFATAL;
337 		}
338 		if (read(f, delbuf, clsz) != clsz) {
339 			perr("Unable to read directory");
340 			return FSFATAL;
341 		}
342 		while (s < e) {
343 			*s = SLOT_DELETED;
344 			s += 32;
345 		}
346 		if (lseek(f, off, SEEK_SET) != off) {
347 			perr("Unable to lseek to %" PRId64, off);
348 			return FSFATAL;
349 		}
350 		if (write(f, delbuf, clsz) != clsz) {
351 			perr("Unable to write directory");
352 			return FSFATAL;
353 		}
354 		if (startcl == endcl)
355 			break;
356 		startcl = fat[startcl].next;
357 		s = delbuf;
358 	}
359 	return FSOK;
360 }
361 
362 static int
363 removede(int f, struct bootblock *boot, struct fatEntry *fat, u_char *start,
364     u_char *end, cl_t startcl, cl_t endcl, cl_t curcl, char *path, int type)
365 {
366 	switch (type) {
367 	case 0:
368 		pwarn("Invalid long filename entry for %s\n", path);
369 		break;
370 	case 1:
371 		pwarn("Invalid long filename entry at end of directory %s\n",
372 		    path);
373 		break;
374 	case 2:
375 		pwarn("Invalid long filename entry for volume label\n");
376 		break;
377 	}
378 	if (ask(0, "Remove")) {
379 		if (startcl != curcl) {
380 			if (delete(f, boot, fat,
381 				   startcl, start - buffer,
382 				   endcl, end - buffer,
383 				   endcl == curcl) == FSFATAL)
384 				return FSFATAL;
385 			start = buffer;
386 		}
387 		/* startcl is < CLUST_FIRST for !fat32 root */
388 		if ((endcl == curcl) || (startcl < CLUST_FIRST))
389 			for (; start < end; start += 32)
390 				*start = SLOT_DELETED;
391 		return FSDIRMOD;
392 	}
393 	return FSERROR;
394 }
395 
396 /*
397  * Check an in-memory file entry
398  */
399 static int
400 checksize(struct bootblock *boot, struct fatEntry *fat, u_char *p,
401     struct dosDirEntry *dir)
402 {
403 	/*
404 	 * Check size on ordinary files
405 	 */
406 	u_int32_t physicalSize;
407 
408 	if (dir->head == CLUST_FREE)
409 		physicalSize = 0;
410 	else {
411 		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
412 			return FSERROR;
413 		physicalSize = fat[dir->head].length * boot->ClusterSize;
414 	}
415 	if (physicalSize < dir->size) {
416 		pwarn("size of %s is %u, should at most be %u\n",
417 		      fullpath(dir), dir->size, physicalSize);
418 		if (ask(1, "Truncate")) {
419 			dir->size = physicalSize;
420 			p[28] = (u_char)physicalSize;
421 			p[29] = (u_char)(physicalSize >> 8);
422 			p[30] = (u_char)(physicalSize >> 16);
423 			p[31] = (u_char)(physicalSize >> 24);
424 			return FSDIRMOD;
425 		} else
426 			return FSERROR;
427 	} else if (physicalSize - dir->size >= boot->ClusterSize) {
428 		pwarn("%s has too many clusters allocated\n",
429 		      fullpath(dir));
430 		if (ask(1, "Drop superfluous clusters")) {
431 			cl_t cl;
432 			u_int32_t sz, len;
433 
434 			for (cl = dir->head, len = sz = 0;
435 			    (sz += boot->ClusterSize) < dir->size; len++)
436 				cl = fat[cl].next;
437 			clearchain(boot, fat, fat[cl].next);
438 			fat[cl].next = CLUST_EOF;
439 			fat[dir->head].length = len;
440 			return FSFATMOD;
441 		} else
442 			return FSERROR;
443 	}
444 	return FSOK;
445 }
446 
447 static const u_char dot_name[11]    = ".          ";
448 static const u_char dotdot_name[11] = "..         ";
449 
450 /*
451  * Basic sanity check if the subdirectory have good '.' and '..' entries,
452  * and they are directory entries.  Further sanity checks are performed
453  * when we traverse into it.
454  */
455 static int
456 check_subdirectory(int f, struct bootblock *boot, struct dosDirEntry *dir)
457 {
458 	u_char *buf, *cp;
459 	off_t off;
460 	cl_t cl;
461 	int retval = FSOK;
462 
463 	cl = dir->head;
464 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
465 		return FSERROR;
466 	}
467 
468 	if (!(boot->flags & FAT32) && !dir->parent) {
469 		off = boot->bpbResSectors + boot->bpbFATs *
470 			boot->FATsecs;
471 	} else {
472 		off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
473 	}
474 
475 	/*
476 	 * We only need to check the first two entries of the directory,
477 	 * which is found in the first sector of the directory entry,
478 	 * so read in only the first sector.
479 	 */
480 	buf = malloc(boot->bpbBytesPerSec);
481 	if (buf == NULL) {
482 		perr("No space for directory buffer (%u)",
483 		    boot->bpbBytesPerSec);
484 		return FSFATAL;
485 	}
486 
487 	off *= boot->bpbBytesPerSec;
488 	if (lseek(f, off, SEEK_SET) != off ||
489 	    read(f, buf, boot->bpbBytesPerSec) != (ssize_t)boot->bpbBytesPerSec) {
490 		perr("Unable to read directory");
491 		free(buf);
492 		return FSFATAL;
493 	}
494 
495 	/*
496 	 * Both `.' and `..' must be present and be the first two entries
497 	 * and be ATTR_DIRECTORY of a valid subdirectory.
498 	 */
499 	cp = buf;
500 	if (memcmp(cp, dot_name, sizeof(dot_name)) != 0 ||
501 	    (cp[11] & ATTR_DIRECTORY) != ATTR_DIRECTORY) {
502 		pwarn("%s: Incorrect `.' for %s.\n", __func__, dir->name);
503 		retval |= FSERROR;
504 	}
505 	cp += 32;
506 	if (memcmp(cp, dotdot_name, sizeof(dotdot_name)) != 0 ||
507 	    (cp[11] & ATTR_DIRECTORY) != ATTR_DIRECTORY) {
508 		pwarn("%s: Incorrect `..' for %s. \n", __func__, dir->name);
509 		retval |= FSERROR;
510 	}
511 
512 	free(buf);
513 	return retval;
514 }
515 
516 /*
517  * Read a directory and
518  *   - resolve long name records
519  *   - enter file and directory records into the parent's list
520  *   - push directories onto the todo-stack
521  */
522 static int
523 readDosDirSection(int f, struct bootblock *boot, struct fatEntry *fat,
524     struct dosDirEntry *dir)
525 {
526 	struct dosDirEntry dirent, *d;
527 	u_char *p, *vallfn, *invlfn, *empty;
528 	off_t off;
529 	int i, j, k, last;
530 	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
531 	char *t;
532 	u_int lidx = 0;
533 	int shortSum;
534 	int mod = FSOK;
535 #define	THISMOD	0x8000			/* Only used within this routine */
536 
537 	cl = dir->head;
538 	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
539 		/*
540 		 * Already handled somewhere else.
541 		 */
542 		return FSOK;
543 	}
544 	shortSum = -1;
545 	vallfn = invlfn = empty = NULL;
546 	do {
547 		if (!(boot->flags & FAT32) && !dir->parent) {
548 			last = boot->bpbRootDirEnts * 32;
549 			off = boot->bpbResSectors + boot->bpbFATs *
550 			    boot->FATsecs;
551 		} else {
552 			last = boot->bpbSecPerClust * boot->bpbBytesPerSec;
553 			off = cl * boot->bpbSecPerClust + boot->ClusterOffset;
554 		}
555 
556 		off *= boot->bpbBytesPerSec;
557 		if (lseek(f, off, SEEK_SET) != off
558 		    || read(f, buffer, last) != last) {
559 			perr("Unable to read directory");
560 			return FSFATAL;
561 		}
562 		last /= 32;
563 		for (p = buffer, i = 0; i < last; i++, p += 32) {
564 			if (dir->fsckflags & DIREMPWARN) {
565 				*p = SLOT_EMPTY;
566 				continue;
567 			}
568 
569 			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
570 				if (*p == SLOT_EMPTY) {
571 					dir->fsckflags |= DIREMPTY;
572 					empty = p;
573 					empcl = cl;
574 				}
575 				continue;
576 			}
577 
578 			if (dir->fsckflags & DIREMPTY) {
579 				if (!(dir->fsckflags & DIREMPWARN)) {
580 					pwarn("%s has entries after end of directory\n",
581 					      fullpath(dir));
582 					if (ask(1, "Extend")) {
583 						u_char *q;
584 
585 						dir->fsckflags &= ~DIREMPTY;
586 						if (delete(f, boot, fat,
587 							   empcl, empty - buffer,
588 							   cl, p - buffer, 1) == FSFATAL)
589 							return FSFATAL;
590 						q = ((empcl == cl) ? empty : buffer);
591 						assert(q != NULL);
592 						for (; q < p; q += 32)
593 							*q = SLOT_DELETED;
594 						mod |= THISMOD|FSDIRMOD;
595 					} else if (ask(0, "Truncate"))
596 						dir->fsckflags |= DIREMPWARN;
597 				}
598 				if (dir->fsckflags & DIREMPWARN) {
599 					*p = SLOT_DELETED;
600 					mod |= THISMOD|FSDIRMOD;
601 					continue;
602 				} else if (dir->fsckflags & DIREMPTY)
603 					mod |= FSERROR;
604 				empty = NULL;
605 			}
606 
607 			if (p[11] == ATTR_WIN95) {
608 				if (*p & LRFIRST) {
609 					if (shortSum != -1) {
610 						if (!invlfn) {
611 							invlfn = vallfn;
612 							invcl = valcl;
613 						}
614 					}
615 					memset(longName, 0, sizeof longName);
616 					shortSum = p[13];
617 					vallfn = p;
618 					valcl = cl;
619 				} else if (shortSum != p[13]
620 					   || lidx != (*p & LRNOMASK)) {
621 					if (!invlfn) {
622 						invlfn = vallfn;
623 						invcl = valcl;
624 					}
625 					if (!invlfn) {
626 						invlfn = p;
627 						invcl = cl;
628 					}
629 					vallfn = NULL;
630 				}
631 				lidx = *p & LRNOMASK;
632 				t = longName + --lidx * 13;
633 				for (k = 1; k < 11 && t < longName +
634 				    sizeof(longName); k += 2) {
635 					if (!p[k] && !p[k + 1])
636 						break;
637 					*t++ = p[k];
638 					/*
639 					 * Warn about those unusable chars in msdosfs here?	XXX
640 					 */
641 					if (p[k + 1])
642 						t[-1] = '?';
643 				}
644 				if (k >= 11)
645 					for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
646 						if (!p[k] && !p[k + 1])
647 							break;
648 						*t++ = p[k];
649 						if (p[k + 1])
650 							t[-1] = '?';
651 					}
652 				if (k >= 26)
653 					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
654 						if (!p[k] && !p[k + 1])
655 							break;
656 						*t++ = p[k];
657 						if (p[k + 1])
658 							t[-1] = '?';
659 					}
660 				if (t >= longName + sizeof(longName)) {
661 					pwarn("long filename too long\n");
662 					if (!invlfn) {
663 						invlfn = vallfn;
664 						invcl = valcl;
665 					}
666 					vallfn = NULL;
667 				}
668 				if (p[26] | (p[27] << 8)) {
669 					pwarn("long filename record cluster start != 0\n");
670 					if (!invlfn) {
671 						invlfn = vallfn;
672 						invcl = cl;
673 					}
674 					vallfn = NULL;
675 				}
676 				continue;	/* long records don't carry further
677 						 * information */
678 			}
679 
680 			/*
681 			 * This is a standard msdosfs directory entry.
682 			 */
683 			memset(&dirent, 0, sizeof dirent);
684 
685 			/*
686 			 * it's a short name record, but we need to know
687 			 * more, so get the flags first.
688 			 */
689 			dirent.flags = p[11];
690 
691 			/*
692 			 * Translate from 850 to ISO here		XXX
693 			 */
694 			for (j = 0; j < 8; j++)
695 				dirent.name[j] = p[j];
696 			dirent.name[8] = '\0';
697 			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
698 				dirent.name[k] = '\0';
699 			if (k < 0 || dirent.name[k] != '\0')
700 				k++;
701 			if (dirent.name[0] == SLOT_E5)
702 				dirent.name[0] = 0xe5;
703 
704 			if (dirent.flags & ATTR_VOLUME) {
705 				if (vallfn || invlfn) {
706 					mod |= removede(f, boot, fat,
707 							invlfn ? invlfn : vallfn, p,
708 							invlfn ? invcl : valcl, -1, 0,
709 							fullpath(dir), 2);
710 					vallfn = NULL;
711 					invlfn = NULL;
712 				}
713 				continue;
714 			}
715 
716 			if (p[8] != ' ')
717 				dirent.name[k++] = '.';
718 			for (j = 0; j < 3; j++)
719 				dirent.name[k++] = p[j+8];
720 			dirent.name[k] = '\0';
721 			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
722 				dirent.name[k] = '\0';
723 
724 			if (vallfn && shortSum != calcShortSum(p)) {
725 				if (!invlfn) {
726 					invlfn = vallfn;
727 					invcl = valcl;
728 				}
729 				vallfn = NULL;
730 			}
731 			dirent.head = p[26] | (p[27] << 8);
732 			if (boot->ClustMask == CLUST32_MASK)
733 				dirent.head |= (p[20] << 16) | (p[21] << 24);
734 			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
735 			if (vallfn) {
736 				strlcpy(dirent.lname, longName,
737 				    sizeof(dirent.lname));
738 				longName[0] = '\0';
739 				shortSum = -1;
740 			}
741 
742 			dirent.parent = dir;
743 			dirent.next = dir->child;
744 
745 			if (invlfn) {
746 				mod |= k = removede(f, boot, fat,
747 						    invlfn, vallfn ? vallfn : p,
748 						    invcl, vallfn ? valcl : cl, cl,
749 						    fullpath(&dirent), 0);
750 				if (mod & FSFATAL)
751 					return FSFATAL;
752 				if (vallfn
753 				    ? (valcl == cl && vallfn != buffer)
754 				    : p != buffer)
755 					if (k & FSDIRMOD)
756 						mod |= THISMOD;
757 			}
758 
759 			vallfn = NULL; /* not used any longer */
760 			invlfn = NULL;
761 
762 			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
763 				if (dirent.head != 0) {
764 					pwarn("%s has clusters, but size 0\n",
765 					      fullpath(&dirent));
766 					if (ask(1, "Drop allocated clusters")) {
767 						p[26] = p[27] = 0;
768 						if (boot->ClustMask == CLUST32_MASK)
769 							p[20] = p[21] = 0;
770 						clearchain(boot, fat, dirent.head);
771 						dirent.head = 0;
772 						mod |= THISMOD|FSDIRMOD|FSFATMOD;
773 					} else
774 						mod |= FSERROR;
775 				}
776 			} else if (dirent.head == 0
777 				   && !strcmp(dirent.name, "..")
778 				   && dir->parent			/* XXX */
779 				   && !dir->parent->parent) {
780 				/*
781 				 *  Do nothing, the parent is the root
782 				 */
783 			} else if (dirent.head < CLUST_FIRST
784 				   || dirent.head >= boot->NumClusters
785 				   || fat[dirent.head].next == CLUST_FREE
786 				   || (fat[dirent.head].next >= CLUST_RSRVD
787 				       && fat[dirent.head].next < CLUST_EOFS)
788 				   || fat[dirent.head].head != dirent.head) {
789 				if (dirent.head == 0)
790 					pwarn("%s has no clusters\n",
791 					      fullpath(&dirent));
792 				else if (dirent.head < CLUST_FIRST
793 					 || dirent.head >= boot->NumClusters)
794 					pwarn("%s starts with cluster out of range(%u)\n",
795 					      fullpath(&dirent),
796 					      dirent.head);
797 				else if (fat[dirent.head].next == CLUST_FREE)
798 					pwarn("%s starts with free cluster\n",
799 					      fullpath(&dirent));
800 				else if (fat[dirent.head].next >= CLUST_RSRVD)
801 					pwarn("%s starts with cluster marked %s\n",
802 					      fullpath(&dirent),
803 					      rsrvdcltype(fat[dirent.head].next));
804 				else
805 					pwarn("%s doesn't start a cluster chain\n",
806 					      fullpath(&dirent));
807 				if (dirent.flags & ATTR_DIRECTORY) {
808 					if (ask(0, "Remove")) {
809 						*p = SLOT_DELETED;
810 						mod |= THISMOD|FSDIRMOD;
811 					} else
812 						mod |= FSERROR;
813 					continue;
814 				} else {
815 					if (ask(1, "Truncate")) {
816 						p[28] = p[29] = p[30] = p[31] = 0;
817 						p[26] = p[27] = 0;
818 						if (boot->ClustMask == CLUST32_MASK)
819 							p[20] = p[21] = 0;
820 						dirent.size = 0;
821 						mod |= THISMOD|FSDIRMOD;
822 					} else
823 						mod |= FSERROR;
824 				}
825 			}
826 
827 			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
828 				fat[dirent.head].flags |= FAT_USED;
829 
830 			if (dirent.flags & ATTR_DIRECTORY) {
831 				/*
832 				 * gather more info for directories
833 				 */
834 				struct dirTodoNode *n;
835 
836 				if (dirent.size) {
837 					pwarn("Directory %s has size != 0\n",
838 					      fullpath(&dirent));
839 					if (ask(1, "Correct")) {
840 						p[28] = p[29] = p[30] = p[31] = 0;
841 						dirent.size = 0;
842 						mod |= THISMOD|FSDIRMOD;
843 					} else
844 						mod |= FSERROR;
845 				}
846 				/*
847 				 * handle `.' and `..' specially
848 				 */
849 				if (strcmp(dirent.name, ".") == 0) {
850 					if (dirent.head != dir->head) {
851 						pwarn("`.' entry in %s has incorrect start cluster\n",
852 						      fullpath(dir));
853 						if (ask(1, "Correct")) {
854 							dirent.head = dir->head;
855 							p[26] = (u_char)dirent.head;
856 							p[27] = (u_char)(dirent.head >> 8);
857 							if (boot->ClustMask == CLUST32_MASK) {
858 								p[20] = (u_char)(dirent.head >> 16);
859 								p[21] = (u_char)(dirent.head >> 24);
860 							}
861 							mod |= THISMOD|FSDIRMOD;
862 						} else
863 							mod |= FSERROR;
864 					}
865 					continue;
866 				}
867 				if (strcmp(dirent.name, "..") == 0) {
868 					if (dir->parent) {		/* XXX */
869 						if (!dir->parent->parent) {
870 							if (dirent.head) {
871 								pwarn("`..' entry in %s has non-zero start cluster\n",
872 								      fullpath(dir));
873 								if (ask(1, "Correct")) {
874 									dirent.head = 0;
875 									p[26] = p[27] = 0;
876 									if (boot->ClustMask == CLUST32_MASK)
877 										p[20] = p[21] = 0;
878 									mod |= THISMOD|FSDIRMOD;
879 								} else
880 									mod |= FSERROR;
881 							}
882 						} else if (dirent.head != dir->parent->head) {
883 							pwarn("`..' entry in %s has incorrect start cluster\n",
884 							      fullpath(dir));
885 							if (ask(1, "Correct")) {
886 								dirent.head = dir->parent->head;
887 								p[26] = (u_char)dirent.head;
888 								p[27] = (u_char)(dirent.head >> 8);
889 								if (boot->ClustMask == CLUST32_MASK) {
890 									p[20] = (u_char)(dirent.head >> 16);
891 									p[21] = (u_char)(dirent.head >> 24);
892 								}
893 								mod |= THISMOD|FSDIRMOD;
894 							} else
895 								mod |= FSERROR;
896 						}
897 					}
898 					continue;
899 				} else {
900 					/*
901 					 * Only one directory entry can point
902 					 * to dir->head, it's '.'.
903 					 */
904 					if (dirent.head == dir->head) {
905 						pwarn("%s entry in %s has incorrect start cluster\n",
906 								dirent.name, fullpath(dir));
907 						if (ask(1, "Remove")) {
908 							*p = SLOT_DELETED;
909 							mod |= THISMOD|FSDIRMOD;
910 						} else
911 							mod |= FSERROR;
912 						continue;
913 					} else if ((check_subdirectory(f, boot,
914 					    &dirent) & FSERROR) == FSERROR) {
915 						/*
916 						 * A subdirectory should have
917 						 * a dot (.) entry and a dot-dot
918 						 * (..) entry of ATTR_DIRECTORY,
919 						 * we will inspect further when
920 						 * traversing into it.
921 						 */
922 						if (ask(1, "Remove")) {
923 							*p = SLOT_DELETED;
924 							mod |= THISMOD|FSDIRMOD;
925 						} else
926 							mod |= FSERROR;
927 						continue;
928 					}
929 				}
930 
931 				/* create directory tree node */
932 				if (!(d = newDosDirEntry())) {
933 					perr("No space for directory");
934 					return FSFATAL;
935 				}
936 				memcpy(d, &dirent, sizeof(struct dosDirEntry));
937 				/* link it into the tree */
938 				dir->child = d;
939 
940 				/* Enter this directory into the todo list */
941 				if (!(n = newDirTodo())) {
942 					perr("No space for todo list");
943 					return FSFATAL;
944 				}
945 				n->next = pendingDirectories;
946 				n->dir = d;
947 				pendingDirectories = n;
948 			} else {
949 				mod |= k = checksize(boot, fat, p, &dirent);
950 				if (k & FSDIRMOD)
951 					mod |= THISMOD;
952 			}
953 			boot->NumFiles++;
954 		}
955 
956 		if (!(boot->flags & FAT32) && !dir->parent)
957 			break;
958 
959 		if (mod & THISMOD) {
960 			last *= 32;
961 			if (lseek(f, off, SEEK_SET) != off
962 			    || write(f, buffer, last) != last) {
963 				perr("Unable to write directory");
964 				return FSFATAL;
965 			}
966 			mod &= ~THISMOD;
967 		}
968 	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
969 	if (invlfn || vallfn)
970 		mod |= removede(f, boot, fat,
971 				invlfn ? invlfn : vallfn, p,
972 				invlfn ? invcl : valcl, -1, 0,
973 				fullpath(dir), 1);
974 
975 	/* The root directory of non fat32 filesystems is in a special
976 	 * area and may have been modified above without being written out.
977 	 */
978 	if ((mod & FSDIRMOD) && !(boot->flags & FAT32) && !dir->parent) {
979 		last *= 32;
980 		if (lseek(f, off, SEEK_SET) != off
981 		    || write(f, buffer, last) != last) {
982 			perr("Unable to write directory");
983 			return FSFATAL;
984 		}
985 		mod &= ~THISMOD;
986 	}
987 	return mod & ~THISMOD;
988 }
989 
990 int
991 handleDirTree(int dosfs, struct bootblock *boot, struct fatEntry *fat)
992 {
993 	int mod;
994 
995 	mod = readDosDirSection(dosfs, boot, fat, rootDir);
996 	if (mod & FSFATAL)
997 		return FSFATAL;
998 
999 	/*
1000 	 * process the directory todo list
1001 	 */
1002 	while (pendingDirectories) {
1003 		struct dosDirEntry *dir = pendingDirectories->dir;
1004 		struct dirTodoNode *n = pendingDirectories->next;
1005 
1006 		/*
1007 		 * remove TODO entry now, the list might change during
1008 		 * directory reads
1009 		 */
1010 		freeDirTodo(pendingDirectories);
1011 		pendingDirectories = n;
1012 
1013 		/*
1014 		 * handle subdirectory
1015 		 */
1016 		mod |= readDosDirSection(dosfs, boot, fat, dir);
1017 		if (mod & FSFATAL)
1018 			return FSFATAL;
1019 	}
1020 
1021 	return mod;
1022 }
1023 
1024 /*
1025  * Try to reconnect a FAT chain into dir
1026  */
1027 static u_char *lfbuf;
1028 static cl_t lfcl;
1029 static off_t lfoff;
1030 
1031 int
1032 reconnect(int dosfs, struct bootblock *boot, struct fatEntry *fat, cl_t head)
1033 {
1034 	struct dosDirEntry d;
1035 	int len;
1036 	u_char *p;
1037 
1038 	if (!ask(1, "Reconnect"))
1039 		return FSERROR;
1040 
1041 	if (!lostDir) {
1042 		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
1043 			if (!strcmp(lostDir->name, LOSTDIR))
1044 				break;
1045 		}
1046 		if (!lostDir) {		/* Create LOSTDIR?		XXX */
1047 			pwarn("No %s directory\n", LOSTDIR);
1048 			return FSERROR;
1049 		}
1050 	}
1051 	if (!lfbuf) {
1052 		lfbuf = malloc(boot->ClusterSize);
1053 		if (!lfbuf) {
1054 			perr("No space for buffer");
1055 			return FSFATAL;
1056 		}
1057 		p = NULL;
1058 	} else
1059 		p = lfbuf;
1060 	while (1) {
1061 		if (p)
1062 			for (; p < lfbuf + boot->ClusterSize; p += 32)
1063 				if (*p == SLOT_EMPTY
1064 				    || *p == SLOT_DELETED)
1065 					break;
1066 		if (p && p < lfbuf + boot->ClusterSize)
1067 			break;
1068 		lfcl = p ? fat[lfcl].next : lostDir->head;
1069 		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
1070 			/* Extend LOSTDIR?				XXX */
1071 			pwarn("No space in %s\n", LOSTDIR);
1072 			lfcl = (lostDir->head < boot->NumClusters) ? lostDir->head : 0;
1073 			return FSERROR;
1074 		}
1075 		lfoff = lfcl * boot->ClusterSize
1076 		    + boot->ClusterOffset * boot->bpbBytesPerSec;
1077 		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
1078 		    || (size_t)read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
1079 			perr("could not read LOST.DIR");
1080 			return FSFATAL;
1081 		}
1082 		p = lfbuf;
1083 	}
1084 
1085 	boot->NumFiles++;
1086 	/* Ensure uniqueness of entry here!				XXX */
1087 	memset(&d, 0, sizeof d);
1088 	/* worst case -1 = 4294967295, 10 digits */
1089 	len = snprintf(d.name, sizeof(d.name), "%u", head);
1090 	d.flags = 0;
1091 	d.head = head;
1092 	d.size = fat[head].length * boot->ClusterSize;
1093 
1094 	memcpy(p, d.name, len);
1095 	memset(p + len, ' ', 11 - len);
1096 	memset(p + 11, 0, 32 - 11);
1097 	p[26] = (u_char)d.head;
1098 	p[27] = (u_char)(d.head >> 8);
1099 	if (boot->ClustMask == CLUST32_MASK) {
1100 		p[20] = (u_char)(d.head >> 16);
1101 		p[21] = (u_char)(d.head >> 24);
1102 	}
1103 	p[28] = (u_char)d.size;
1104 	p[29] = (u_char)(d.size >> 8);
1105 	p[30] = (u_char)(d.size >> 16);
1106 	p[31] = (u_char)(d.size >> 24);
1107 	fat[head].flags |= FAT_USED;
1108 	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
1109 	    || (size_t)write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
1110 		perr("could not write LOST.DIR");
1111 		return FSFATAL;
1112 	}
1113 	return FSDIRMOD;
1114 }
1115 
1116 void
1117 finishlf(void)
1118 {
1119 	if (lfbuf)
1120 		free(lfbuf);
1121 	lfbuf = NULL;
1122 }
1123