Add fsck_msdosfs.

Obtained from:	NetBSD

1 files changed, 1017 insertions, 0 deletions

diff --git a/sbin/fsck_msdosfs/dir.c b/sbin/fsck_msdosfs/dir.c
new file mode 100644
index 000000000000..64636cbd0e6f
--- /dev/null
+++ b/sbin/fsck_msdosfs/dir.c
@@ -0,0 +1,1017 @@
+/*
+ * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
+ * Copyright (c) 1995 Martin Husemann
+ * Some structure declaration borrowed from Paul Popelka
+ * (paulp@uts.amdahl.com), see /sys/msdosfs/ for reference.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by Martin Husemann
+ *	and Wolfgang Solfrank.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+#include <sys/cdefs.h>
+#ifndef lint
+__RCSID("$NetBSD: dir.c,v 1.14 1998/08/25 19:18:15 ross Exp $");
+static const char rcsid[] =
+  "$FreeBSD$";
+#endif /* not lint */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <time.h>
+
+#include <sys/param.h>
+
+#include "ext.h"
+#include "fsutil.h"
+
+#define	SLOT_EMPTY	0x00		/* slot has never been used */
+#define	SLOT_E5		0x05		/* the real value is 0xe5 */
+#define	SLOT_DELETED	0xe5		/* file in this slot deleted */
+
+#define	ATTR_NORMAL	0x00		/* normal file */
+#define	ATTR_READONLY	0x01		/* file is readonly */
+#define	ATTR_HIDDEN	0x02		/* file is hidden */
+#define	ATTR_SYSTEM	0x04		/* file is a system file */
+#define	ATTR_VOLUME	0x08		/* entry is a volume label */
+#define	ATTR_DIRECTORY	0x10		/* entry is a directory name */
+#define	ATTR_ARCHIVE	0x20		/* file is new or modified */
+
+#define	ATTR_WIN95	0x0f		/* long name record */
+
+/*
+ * This is the format of the contents of the deTime field in the direntry
+ * structure.
+ * We don't use bitfields because we don't know how compilers for
+ * arbitrary machines will lay them out.
+ */
+#define DT_2SECONDS_MASK	0x1F	/* seconds divided by 2 */
+#define DT_2SECONDS_SHIFT	0
+#define DT_MINUTES_MASK		0x7E0	/* minutes */
+#define DT_MINUTES_SHIFT	5
+#define DT_HOURS_MASK		0xF800	/* hours */
+#define DT_HOURS_SHIFT		11
+
+/*
+ * This is the format of the contents of the deDate field in the direntry
+ * structure.
+ */
+#define DD_DAY_MASK		0x1F	/* day of month */
+#define DD_DAY_SHIFT		0
+#define DD_MONTH_MASK		0x1E0	/* month */
+#define DD_MONTH_SHIFT		5
+#define DD_YEAR_MASK		0xFE00	/* year - 1980 */
+#define DD_YEAR_SHIFT		9
+
+
+/* dir.c */
+static struct dosDirEntry *newDosDirEntry __P((void));
+static void freeDosDirEntry __P((struct dosDirEntry *));
+static struct dirTodoNode *newDirTodo __P((void));
+static void freeDirTodo __P((struct dirTodoNode *));
+static char *fullpath __P((struct dosDirEntry *));
+static u_char calcShortSum __P((u_char *));
+static int delete __P((int, struct bootblock *, struct fatEntry *, cl_t, int,
+    cl_t, int, int));
+static int removede __P((int, struct bootblock *, struct fatEntry *, u_char *,
+    u_char *, cl_t, cl_t, cl_t, char *, int));
+static int checksize __P((struct bootblock *, struct fatEntry *, u_char *,
+    struct dosDirEntry *));
+static int readDosDirSection __P((int, struct bootblock *, struct fatEntry *,
+    struct dosDirEntry *));
+
+/*
+ * Manage free dosDirEntry structures.
+ */
+static struct dosDirEntry *freede;
+
+static struct dosDirEntry *
+newDosDirEntry()
+{
+	struct dosDirEntry *de;
+
+	if (!(de = freede)) {
+		if (!(de = (struct dosDirEntry *)malloc(sizeof *de)))
+			return 0;
+	} else
+		freede = de->next;
+	return de;
+}
+
+static void
+freeDosDirEntry(de)
+	struct dosDirEntry *de;
+{
+	de->next = freede;
+	freede = de;
+}
+
+/*
+ * The same for dirTodoNode structures.
+ */
+static struct dirTodoNode *freedt;
+
+static struct dirTodoNode *
+newDirTodo()
+{
+	struct dirTodoNode *dt;
+
+	if (!(dt = freedt)) {
+		if (!(dt = (struct dirTodoNode *)malloc(sizeof *dt)))
+			return 0;
+	} else
+		freedt = dt->next;
+	return dt;
+}
+
+static void
+freeDirTodo(dt)
+	struct dirTodoNode *dt;
+{
+	dt->next = freedt;
+	freedt = dt;
+}
+
+/*
+ * The stack of unread directories
+ */
+struct dirTodoNode *pendingDirectories = NULL;
+
+/*
+ * Return the full pathname for a directory entry.
+ */
+static char *
+fullpath(dir)
+	struct dosDirEntry *dir;
+{
+	static char namebuf[MAXPATHLEN + 1];
+	char *cp, *np;
+	int nl;
+
+	cp = namebuf + sizeof namebuf - 1;
+	*cp = '\0';
+	do {
+		np = dir->lname[0] ? dir->lname : dir->name;
+		nl = strlen(np);
+		if ((cp -= nl) <= namebuf + 1)
+			break;
+		memcpy(cp, np, nl);
+		*--cp = '/';
+	} while ((dir = dir->parent) != NULL);
+	if (dir)
+		*--cp = '?';
+	else
+		cp++;
+	return cp;
+}
+
+/*
+ * Calculate a checksum over an 8.3 alias name
+ */
+static u_char
+calcShortSum(p)
+	u_char *p;
+{
+	u_char sum = 0;
+	int i;
+
+	for (i = 0; i < 11; i++) {
+		sum = (sum << 7)|(sum >> 1);	/* rotate right */
+		sum += p[i];
+	}
+
+	return sum;
+}
+
+/*
+ * Global variables temporarily used during a directory scan
+ */
+static char longName[DOSLONGNAMELEN] = "";
+static u_char *buffer = NULL;
+static u_char *delbuf = NULL;
+
+struct dosDirEntry *rootDir;
+static struct dosDirEntry *lostDir;
+
+/*
+ * Init internal state for a new directory scan.
+ */
+int
+resetDosDirSection(boot, fat)
+	struct bootblock *boot;
+	struct fatEntry *fat;
+{
+	int b1, b2;
+	cl_t cl;
+	int ret = FSOK;
+
+	b1 = boot->RootDirEnts * 32;
+	b2 = boot->SecPerClust * boot->BytesPerSec;
+
+	if (!(buffer = malloc(b1 > b2 ? b1 : b2))
+	    || !(delbuf = malloc(b2))
+	    || !(rootDir = newDosDirEntry())) {
+		perror("No space for directory");
+		return FSFATAL;
+	}
+	memset(rootDir, 0, sizeof *rootDir);
+	if (boot->flags & FAT32) {
+		if (boot->RootCl < CLUST_FIRST || boot->RootCl >= boot->NumClusters) {
+			pfatal("Root directory starts with cluster out of range(%u)",
+			       boot->RootCl);
+			return FSFATAL;
+		}
+		cl = fat[boot->RootCl].next;
+		if (cl < CLUST_FIRST
+		    || (cl >= CLUST_RSRVD && cl< CLUST_EOFS)
+		    || fat[boot->RootCl].head != boot->RootCl) {
+			if (cl == CLUST_FREE)
+				pwarn("Root directory starts with free cluster\n");
+			else if (cl >= CLUST_RSRVD)
+				pwarn("Root directory starts with cluster marked %s\n",
+				      rsrvdcltype(cl));
+			else {
+				pfatal("Root directory doesn't start a cluster chain");
+				return FSFATAL;
+			}
+			if (ask(1, "Fix")) {
+				fat[boot->RootCl].next = CLUST_FREE;
+				ret = FSFATMOD;
+			} else
+				ret = FSFATAL;
+		}
+
+		fat[boot->RootCl].flags |= FAT_USED;
+		rootDir->head = boot->RootCl;
+	}
+
+	return ret;
+}
+
+/*
+ * Cleanup after a directory scan
+ */
+void
+finishDosDirSection()
+{
+	struct dirTodoNode *p, *np;
+	struct dosDirEntry *d, *nd;
+
+	for (p = pendingDirectories; p; p = np) {
+		np = p->next;
+		freeDirTodo(p);
+	}
+	pendingDirectories = 0;
+	for (d = rootDir; d; d = nd) {
+		if ((nd = d->child) != NULL) {
+			d->child = 0;
+			continue;
+		}
+		if (!(nd = d->next))
+			nd = d->parent;
+		freeDosDirEntry(d);
+	}
+	rootDir = lostDir = NULL;
+	free(buffer);
+	free(delbuf);
+	buffer = NULL;
+	delbuf = NULL;
+}
+
+/*
+ * Delete directory entries between startcl, startoff and endcl, endoff.
+ */
+static int
+delete(f, boot, fat, startcl, startoff, endcl, endoff, notlast)
+	int f;
+	struct bootblock *boot;
+	struct fatEntry *fat;
+	cl_t startcl;
+	int startoff;
+	cl_t endcl;
+	int endoff;
+	int notlast;
+{
+	u_char *s, *e;
+	off_t off;
+	int clsz = boot->SecPerClust * boot->BytesPerSec;
+
+	s = delbuf + startoff;
+	e = delbuf + clsz;
+	while (startcl >= CLUST_FIRST && startcl < boot->NumClusters) {
+		if (startcl == endcl) {
+			if (notlast)
+				break;
+			e = delbuf + endoff;
+		}
+		off = startcl * boot->SecPerClust + boot->ClusterOffset;
+		off *= boot->BytesPerSec;
+		if (lseek(f, off, SEEK_SET) != off
+		    || read(f, delbuf, clsz) != clsz) {
+			perror("Unable to read directory");
+			return FSFATAL;
+		}
+		while (s < e) {
+			*s = SLOT_DELETED;
+			s += 32;
+		}
+		if (lseek(f, off, SEEK_SET) != off
+		    || write(f, delbuf, clsz) != clsz) {
+			perror("Unable to write directory");
+			return FSFATAL;
+		}
+		if (startcl == endcl)
+			break;
+		startcl = fat[startcl].next;
+		s = delbuf;
+	}
+	return FSOK;
+}
+
+static int
+removede(f, boot, fat, start, end, startcl, endcl, curcl, path, type)
+	int f;
+	struct bootblock *boot;
+	struct fatEntry *fat;
+	u_char *start;
+	u_char *end;
+	cl_t startcl;
+	cl_t endcl;
+	cl_t curcl;
+	char *path;
+	int type;
+{
+	switch (type) {
+	case 0:
+		pwarn("Invalid long filename entry for %s\n", path);
+		break;
+	case 1:
+		pwarn("Invalid long filename entry at end of directory %s\n", path);
+		break;
+	case 2:
+		pwarn("Invalid long filename entry for volume label\n");
+		break;
+	}
+	if (ask(0, "Remove")) {
+		if (startcl != curcl) {
+			if (delete(f, boot, fat,
+				   startcl, start - buffer,
+				   endcl, end - buffer,
+				   endcl == curcl) == FSFATAL)
+				return FSFATAL;
+			start = buffer;
+		}
+		if (endcl == curcl)
+			for (; start < end; start += 32)
+				*start = SLOT_DELETED;
+		return FSDIRMOD;
+	}
+	return FSERROR;
+}
+
+/*
+ * Check an in-memory file entry
+ */
+static int
+checksize(boot, fat, p, dir)
+	struct bootblock *boot;
+	struct fatEntry *fat;
+	u_char *p;
+	struct dosDirEntry *dir;
+{
+	/*
+	 * Check size on ordinary files
+	 */
+	int32_t physicalSize;
+
+	if (dir->head == CLUST_FREE)
+		physicalSize = 0;
+	else {
+		if (dir->head < CLUST_FIRST || dir->head >= boot->NumClusters)
+			return FSERROR;
+		physicalSize = fat[dir->head].length * boot->ClusterSize;
+	}
+	if (physicalSize < dir->size) {
+		pwarn("size of %s is %u, should at most be %u\n",
+		      fullpath(dir), dir->size, physicalSize);
+		if (ask(1, "Truncate")) {
+			dir->size = physicalSize;
+			p[28] = (u_char)physicalSize;
+			p[29] = (u_char)(physicalSize >> 8);
+			p[30] = (u_char)(physicalSize >> 16);
+			p[31] = (u_char)(physicalSize >> 24);
+			return FSDIRMOD;
+		} else
+			return FSERROR;
+	} else if (physicalSize - dir->size >= boot->ClusterSize) {
+		pwarn("%s has too many clusters allocated\n",
+		      fullpath(dir));
+		if (ask(1, "Drop superfluous clusters")) {
+			cl_t cl;
+			u_int32_t sz = 0;
+
+			for (cl = dir->head; (sz += boot->ClusterSize) < dir->size;)
+				cl = fat[cl].next;
+			clearchain(boot, fat, fat[cl].next);
+			fat[cl].next = CLUST_EOF;
+			return FSFATMOD;
+		} else
+			return FSERROR;
+	}
+	return FSOK;
+}
+
+/*
+ * Read a directory and
+ *   - resolve long name records
+ *   - enter file and directory records into the parent's list
+ *   - push directories onto the todo-stack
+ */
+static int
+readDosDirSection(f, boot, fat, dir)
+	int f;
+	struct bootblock *boot;
+	struct fatEntry *fat;
+	struct dosDirEntry *dir;
+{
+	struct dosDirEntry dirent, *d;
+	u_char *p, *vallfn, *invlfn, *empty;
+	off_t off;
+	int i, j, k, last;
+	cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
+	char *t;
+	u_int lidx = 0;
+	int shortSum;
+	int mod = FSOK;
+#define	THISMOD	0x8000			/* Only used within this routine */
+
+	cl = dir->head;
+	if (dir->parent && (cl < CLUST_FIRST || cl >= boot->NumClusters)) {
+		/*
+		 * Already handled somewhere else.
+		 */
+		return FSOK;
+	}
+	shortSum = -1;
+	vallfn = invlfn = empty = NULL;
+	do {
+		if (!(boot->flags & FAT32) && !dir->parent) {
+			last = boot->RootDirEnts * 32;
+			off = boot->ResSectors + boot->FATs * boot->FATsecs;
+		} else {
+			last = boot->SecPerClust * boot->BytesPerSec;
+			off = cl * boot->SecPerClust + boot->ClusterOffset;
+		}
+
+		off *= boot->BytesPerSec;
+		if (lseek(f, off, SEEK_SET) != off
+		    || read(f, buffer, last) != last) {
+			perror("Unable to read directory");
+			return FSFATAL;
+		}
+		last /= 32;
+		/*
+		 * Check `.' and `..' entries here?			XXX
+		 */
+		for (p = buffer, i = 0; i < last; i++, p += 32) {
+			if (dir->fsckflags & DIREMPWARN) {
+				*p = SLOT_EMPTY;
+				continue;
+			}
+
+			if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
+				if (*p == SLOT_EMPTY) {
+					dir->fsckflags |= DIREMPTY;
+					empty = p;
+					empcl = cl;
+				}
+				continue;
+			}
+
+			if (dir->fsckflags & DIREMPTY) {
+				if (!(dir->fsckflags & DIREMPWARN)) {
+					pwarn("%s has entries after end of directory\n",
+					      fullpath(dir));
+					if (ask(1, "Extend")) {
+						u_char *q;
+
+						dir->fsckflags &= ~DIREMPTY;
+						if (delete(f, boot, fat,
+							   empcl, empty - buffer,
+							   cl, p - buffer, 1) == FSFATAL)
+							return FSFATAL;
+						q = empcl == cl ? empty : buffer;
+						for (; q < p; q += 32)
+							*q = SLOT_DELETED;
+						mod |= THISMOD|FSDIRMOD;
+					} else if (ask(0, "Truncate"))
+						dir->fsckflags |= DIREMPWARN;
+				}
+				if (dir->fsckflags & DIREMPWARN) {
+					*p = SLOT_DELETED;
+					mod |= THISMOD|FSDIRMOD;
+					continue;
+				} else if (dir->fsckflags & DIREMPTY)
+					mod |= FSERROR;
+				empty = NULL;
+			}
+
+			if (p[11] == ATTR_WIN95) {
+				if (*p & LRFIRST) {
+					if (shortSum != -1) {
+						if (!invlfn) {
+							invlfn = vallfn;
+							invcl = valcl;
+						}
+					}
+					memset(longName, 0, sizeof longName);
+					shortSum = p[13];
+					vallfn = p;
+					valcl = cl;
+				} else if (shortSum != p[13]
+					   || lidx != (*p & LRNOMASK)) {
+					if (!invlfn) {
+						invlfn = vallfn;
+						invcl = valcl;
+					}
+					if (!invlfn) {
+						invlfn = p;
+						invcl = cl;
+					}
+					vallfn = NULL;
+				}
+				lidx = *p & LRNOMASK;
+				t = longName + --lidx * 13;
+				for (k = 1; k < 11 && t < longName + sizeof(longName); k += 2) {
+					if (!p[k] && !p[k + 1])
+						break;
+					*t++ = p[k];
+					/*
+					 * Warn about those unusable chars in msdosfs here?	XXX
+					 */
+					if (p[k + 1])
+						t[-1] = '?';
+				}
+				if (k >= 11)
+					for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
+						if (!p[k] && !p[k + 1])
+							break;
+						*t++ = p[k];
+						if (p[k + 1])
+							t[-1] = '?';
+					}
+				if (k >= 26)
+					for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
+						if (!p[k] && !p[k + 1])
+							break;
+						*t++ = p[k];
+						if (p[k + 1])
+							t[-1] = '?';
+					}
+				if (t >= longName + sizeof(longName)) {
+					pwarn("long filename too long\n");
+					if (!invlfn) {
+						invlfn = vallfn;
+						invcl = valcl;
+					}
+					vallfn = NULL;
+				}
+				if (p[26] | (p[27] << 8)) {
+					pwarn("long filename record cluster start != 0\n");
+					if (!invlfn) {
+						invlfn = vallfn;
+						invcl = cl;
+					}
+					vallfn = NULL;
+				}
+				continue;	/* long records don't carry further
+						 * information */
+			}
+
+			/*
+			 * This is a standard msdosfs directory entry.
+			 */
+			memset(&dirent, 0, sizeof dirent);
+
+			/*
+			 * it's a short name record, but we need to know
+			 * more, so get the flags first.
+			 */
+			dirent.flags = p[11];
+
+			/*
+			 * Translate from 850 to ISO here		XXX
+			 */
+			for (j = 0; j < 8; j++)
+				dirent.name[j] = p[j];
+			dirent.name[8] = '\0';
+			for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
+				dirent.name[k] = '\0';
+			if (dirent.name[k] != '\0')
+				k++;
+			if (dirent.name[0] == SLOT_E5)
+				dirent.name[0] = 0xe5;
+
+			if (dirent.flags & ATTR_VOLUME) {
+				if (vallfn || invlfn) {
+					mod |= removede(f, boot, fat,
+							invlfn ? invlfn : vallfn, p,
+							invlfn ? invcl : valcl, -1, 0,
+							fullpath(dir), 2);
+					vallfn = NULL;
+					invlfn = NULL;
+				}
+				continue;
+			}
+
+			if (p[8] != ' ')
+				dirent.name[k++] = '.';
+			for (j = 0; j < 3; j++)
+				dirent.name[k++] = p[j+8];
+			dirent.name[k] = '\0';
+			for (k--; k >= 0 && dirent.name[k] == ' '; k--)
+				dirent.name[k] = '\0';
+
+			if (vallfn && shortSum != calcShortSum(p)) {
+				if (!invlfn) {
+					invlfn = vallfn;
+					invcl = valcl;
+				}
+				vallfn = NULL;
+			}
+			dirent.head = p[26] | (p[27] << 8);
+			if (boot->ClustMask == CLUST32_MASK)
+				dirent.head |= (p[20] << 16) | (p[21] << 24);
+			dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
+			if (vallfn) {
+				strcpy(dirent.lname, longName);
+				longName[0] = '\0';
+				shortSum = -1;
+			}
+
+			dirent.parent = dir;
+			dirent.next = dir->child;
+
+			if (invlfn) {
+				mod |= k = removede(f, boot, fat,
+						    invlfn, vallfn ? vallfn : p,
+						    invcl, vallfn ? valcl : cl, cl,
+						    fullpath(&dirent), 0);
+				if (mod & FSFATAL)
+					return FSFATAL;
+				if (vallfn
+				    ? (valcl == cl && vallfn != buffer)
+				    : p != buffer)
+					if (k & FSDIRMOD)
+						mod |= THISMOD;
+			}
+
+			vallfn = NULL; /* not used any longer */
+			invlfn = NULL;
+
+			if (dirent.size == 0 && !(dirent.flags & ATTR_DIRECTORY)) {
+				if (dirent.head != 0) {
+					pwarn("%s has clusters, but size 0\n",
+					      fullpath(&dirent));
+					if (ask(1, "Drop allocated clusters")) {
+						p[26] = p[27] = 0;
+						if (boot->ClustMask == CLUST32_MASK)
+							p[20] = p[21] = 0;
+						clearchain(boot, fat, dirent.head);
+						dirent.head = 0;
+						mod |= THISMOD|FSDIRMOD|FSFATMOD;
+					} else
+						mod |= FSERROR;
+				}
+			} else if (dirent.head == 0
+				   && !strcmp(dirent.name, "..")
+				   && dir->parent			/* XXX */
+				   && !dir->parent->parent) {
+				/*
+				 *  Do nothing, the parent is the root
+				 */
+			} else if (dirent.head < CLUST_FIRST
+				   || dirent.head >= boot->NumClusters
+				   || fat[dirent.head].next == CLUST_FREE
+				   || (fat[dirent.head].next >= CLUST_RSRVD
+				       && fat[dirent.head].next < CLUST_EOFS)
+				   || fat[dirent.head].head != dirent.head) {
+				if (dirent.head == 0)
+					pwarn("%s has no clusters\n",
+					      fullpath(&dirent));
+				else if (dirent.head < CLUST_FIRST
+					 || dirent.head >= boot->NumClusters)
+					pwarn("%s starts with cluster out of range(%u)\n",
+					      fullpath(&dirent),
+					      dirent.head);
+				else if (fat[dirent.head].next == CLUST_FREE)
+					pwarn("%s starts with free cluster\n",
+					      fullpath(&dirent));
+				else if (fat[dirent.head].next >= CLUST_RSRVD)
+					pwarn("%s starts with cluster marked %s\n",
+					      fullpath(&dirent),
+					      rsrvdcltype(fat[dirent.head].next));
+				else
+					pwarn("%s doesn't start a cluster chain\n",
+					      fullpath(&dirent));
+				if (dirent.flags & ATTR_DIRECTORY) {
+					if (ask(0, "Remove")) {
+						*p = SLOT_DELETED;
+						mod |= THISMOD|FSDIRMOD;
+					} else
+						mod |= FSERROR;
+					continue;
+				} else {
+					if (ask(1, "Truncate")) {
+						p[28] = p[29] = p[30] = p[31] = 0;
+						p[26] = p[27] = 0;
+						if (boot->ClustMask == CLUST32_MASK)
+							p[20] = p[21] = 0;
+						dirent.size = 0;
+						mod |= THISMOD|FSDIRMOD;
+					} else
+						mod |= FSERROR;
+				}
+			}
+
+			if (dirent.head >= CLUST_FIRST && dirent.head < boot->NumClusters)
+				fat[dirent.head].flags |= FAT_USED;
+
+			if (dirent.flags & ATTR_DIRECTORY) {
+				/*
+				 * gather more info for directories
+				 */
+				struct dirTodoNode *n;
+
+				if (dirent.size) {
+					pwarn("Directory %s has size != 0\n",
+					      fullpath(&dirent));
+					if (ask(1, "Correct")) {
+						p[28] = p[29] = p[30] = p[31] = 0;
+						dirent.size = 0;
+						mod |= THISMOD|FSDIRMOD;
+					} else
+						mod |= FSERROR;
+				}
+				/*
+				 * handle `.' and `..' specially
+				 */
+				if (strcmp(dirent.name, ".") == 0) {
+					if (dirent.head != dir->head) {
+						pwarn("`.' entry in %s has incorrect start cluster\n",
+						      fullpath(dir));
+						if (ask(1, "Correct")) {
+							dirent.head = dir->head;
+							p[26] = (u_char)dirent.head;
+							p[27] = (u_char)(dirent.head >> 8);
+							if (boot->ClustMask == CLUST32_MASK) {
+								p[20] = (u_char)(dirent.head >> 16);
+								p[21] = (u_char)(dirent.head >> 24);
+							}
+							mod |= THISMOD|FSDIRMOD;
+						} else
+							mod |= FSERROR;
+					}
+					continue;
+				}
+				if (strcmp(dirent.name, "..") == 0) {
+					if (dir->parent) {		/* XXX */
+						if (!dir->parent->parent) {
+							if (dirent.head) {
+								pwarn("`..' entry in %s has non-zero start cluster\n",
+								      fullpath(dir));
+								if (ask(1, "Correct")) {
+									dirent.head = 0;
+									p[26] = p[27] = 0;
+									if (boot->ClustMask == CLUST32_MASK)
+										p[20] = p[21] = 0;
+									mod |= THISMOD|FSDIRMOD;
+								} else
+									mod |= FSERROR;
+							}
+						} else if (dirent.head != dir->parent->head) {
+							pwarn("`..' entry in %s has incorrect start cluster\n",
+							      fullpath(dir));
+							if (ask(1, "Correct")) {
+								dirent.head = dir->parent->head;
+								p[26] = (u_char)dirent.head;
+								p[27] = (u_char)(dirent.head >> 8);
+								if (boot->ClustMask == CLUST32_MASK) {
+									p[20] = (u_char)(dirent.head >> 16);
+									p[21] = (u_char)(dirent.head >> 24);
+								}
+								mod |= THISMOD|FSDIRMOD;
+							} else
+								mod |= FSERROR;
+						}
+					}
+					continue;
+				}
+
+				/* create directory tree node */
+				if (!(d = newDosDirEntry())) {
+					perror("No space for directory");
+					return FSFATAL;
+				}
+				memcpy(d, &dirent, sizeof(struct dosDirEntry));
+				/* link it into the tree */
+				dir->child = d;
+
+				/* Enter this directory into the todo list */
+				if (!(n = newDirTodo())) {
+					perror("No space for todo list");
+					return FSFATAL;
+				}
+				n->next = pendingDirectories;
+				n->dir = d;
+				pendingDirectories = n;
+			} else {
+				mod |= k = checksize(boot, fat, p, &dirent);
+				if (k & FSDIRMOD)
+					mod |= THISMOD;
+			}
+			boot->NumFiles++;
+		}
+		if (mod & THISMOD) {
+			last *= 32;
+			if (lseek(f, off, SEEK_SET) != off
+			    || write(f, buffer, last) != last) {
+				perror("Unable to write directory");
+				return FSFATAL;
+			}
+			mod &= ~THISMOD;
+		}
+	} while ((cl = fat[cl].next) >= CLUST_FIRST && cl < boot->NumClusters);
+	if (invlfn || vallfn)
+		mod |= removede(f, boot, fat,
+				invlfn ? invlfn : vallfn, p,
+				invlfn ? invcl : valcl, -1, 0,
+				fullpath(dir), 1);
+	return mod & ~THISMOD;
+}
+
+int
+handleDirTree(dosfs, boot, fat)
+	int dosfs;
+	struct bootblock *boot;
+	struct fatEntry *fat;
+{
+	int mod;
+
+	mod = readDosDirSection(dosfs, boot, fat, rootDir);
+	if (mod & FSFATAL)
+		return FSFATAL;
+
+	/*
+	 * process the directory todo list
+	 */
+	while (pendingDirectories) {
+		struct dosDirEntry *dir = pendingDirectories->dir;
+		struct dirTodoNode *n = pendingDirectories->next;
+
+		/*
+		 * remove TODO entry now, the list might change during
+		 * directory reads
+		 */
+		freeDirTodo(pendingDirectories);
+		pendingDirectories = n;
+
+		/*
+		 * handle subdirectory
+		 */
+		mod |= readDosDirSection(dosfs, boot, fat, dir);
+		if (mod & FSFATAL)
+			return FSFATAL;
+	}
+
+	return mod;
+}
+
+/*
+ * Try to reconnect a FAT chain into dir
+ */
+static u_char *lfbuf;
+static cl_t lfcl;
+static off_t lfoff;
+
+int
+reconnect(dosfs, boot, fat, head)
+	int dosfs;
+	struct bootblock *boot;
+	struct fatEntry *fat;
+	cl_t head;
+{
+	struct dosDirEntry d;
+	u_char *p;
+
+	if (!ask(1, "Reconnect"))
+		return FSERROR;
+
+	if (!lostDir) {
+		for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
+			if (!strcmp(lostDir->name, LOSTDIR))
+				break;
+		}
+		if (!lostDir) {		/* Create LOSTDIR?		XXX */
+			pwarn("No %s directory\n", LOSTDIR);
+			return FSERROR;
+		}
+	}
+	if (!lfbuf) {
+		lfbuf = malloc(boot->ClusterSize);
+		if (!lfbuf) {
+			perror("No space for buffer");
+			return FSFATAL;
+		}
+		p = NULL;
+	} else
+		p = lfbuf;
+	while (1) {
+		if (p)
+			for (; p < lfbuf + boot->ClusterSize; p += 32)
+				if (*p == SLOT_EMPTY
+				    || *p == SLOT_DELETED)
+					break;
+		if (p && p < lfbuf + boot->ClusterSize)
+			break;
+		lfcl = p ? fat[lfcl].next : lostDir->head;
+		if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
+			/* Extend LOSTDIR?				XXX */
+			pwarn("No space in %s\n", LOSTDIR);
+			return FSERROR;
+		}
+		lfoff = lfcl * boot->ClusterSize
+		    + boot->ClusterOffset * boot->BytesPerSec;
+		if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
+		    || read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
+			perror("could not read LOST.DIR");
+			return FSFATAL;
+		}
+		p = lfbuf;
+	}
+
+	boot->NumFiles++;
+	/* Ensure uniqueness of entry here!				XXX */
+	memset(&d, 0, sizeof d);
+	(void)snprintf(d.name, sizeof(d.name), "%u", head);
+	d.flags = 0;
+	d.head = head;
+	d.size = fat[head].length * boot->ClusterSize;
+
+	memset(p, 0, 32);
+	memset(p, ' ', 11);
+	memcpy(p, d.name, strlen(d.name));
+	p[26] = (u_char)d.head;
+	p[27] = (u_char)(d.head >> 8);
+	if (boot->ClustMask == CLUST32_MASK) {
+		p[20] = (u_char)(d.head >> 16);
+		p[21] = (u_char)(d.head >> 24);
+	}
+	p[28] = (u_char)d.size;
+	p[29] = (u_char)(d.size >> 8);
+	p[30] = (u_char)(d.size >> 16);
+	p[31] = (u_char)(d.size >> 24);
+	fat[head].flags |= FAT_USED;
+	if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
+	    || write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
+		perror("could not write LOST.DIR");
+		return FSFATAL;
+	}
+	return FSDIRMOD;
+}
+
+void
+finishlf()
+{
+	if (lfbuf)
+		free(lfbuf);
+	lfbuf = NULL;
+}