sbin/fsck_msdosfs/dir.c

   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 }