sbin/fsck_msdosfs/dir.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2019 Google LLC
   5  * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
   6  * Copyright (c) 1995 Martin Husemann
   7  * Some structure declaration borrowed from Paul Popelka
   8  * (paulp@uts.amdahl.com), see /sys/msdosfs/ for reference.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 __RCSID("$NetBSD: dir.c,v 1.20 2006/06/05 16:51:18 christos Exp $");
  35 static const char rcsid[] =
  36   "$FreeBSD$";
  37 #endif /* not lint */
  38
  39 #include <assert.h>
  40 #include <inttypes.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <ctype.h>
  45 #include <unistd.h>
  46 #include <time.h>
  47
  48 #include <sys/param.h>
  49
  50 #include "ext.h"
  51 #include "fsutil.h"
  52
  53 #define SLOT_EMPTY      0x00            /* slot has never been used */
  54 #define SLOT_E5         0x05            /* the real value is 0xe5 */
  55 #define SLOT_DELETED    0xe5            /* file in this slot deleted */
  56
  57 #define ATTR_NORMAL     0x00            /* normal file */
  58 #define ATTR_READONLY   0x01            /* file is readonly */
  59 #define ATTR_HIDDEN     0x02            /* file is hidden */
  60 #define ATTR_SYSTEM     0x04            /* file is a system file */
  61 #define ATTR_VOLUME     0x08            /* entry is a volume label */
  62 #define ATTR_DIRECTORY  0x10            /* entry is a directory name */
  63 #define ATTR_ARCHIVE    0x20            /* file is new or modified */
  64
  65 #define ATTR_WIN95      0x0f            /* long name record */
  66
  67 /*
  68  * This is the format of the contents of the deTime field in the direntry
  69  * structure.
  70  * We don't use bitfields because we don't know how compilers for
  71  * arbitrary machines will lay them out.
  72  */
  73 #define DT_2SECONDS_MASK        0x1F    /* seconds divided by 2 */
  74 #define DT_2SECONDS_SHIFT       0
  75 #define DT_MINUTES_MASK         0x7E0   /* minutes */
  76 #define DT_MINUTES_SHIFT        5
  77 #define DT_HOURS_MASK           0xF800  /* hours */
  78 #define DT_HOURS_SHIFT          11
  79
  80 /*
  81  * This is the format of the contents of the deDate field in the direntry
  82  * structure.
  83  */
  84 #define DD_DAY_MASK             0x1F    /* day of month */
  85 #define DD_DAY_SHIFT            0
  86 #define DD_MONTH_MASK           0x1E0   /* month */
  87 #define DD_MONTH_SHIFT          5
  88 #define DD_YEAR_MASK            0xFE00  /* year - 1980 */
  89 #define DD_YEAR_SHIFT           9
  90
  91
  92 /* dir.c */
  93 static struct dosDirEntry *newDosDirEntry(void);
  94 static void freeDosDirEntry(struct dosDirEntry *);
  95 static struct dirTodoNode *newDirTodo(void);
  96 static void freeDirTodo(struct dirTodoNode *);
  97 static char *fullpath(struct dosDirEntry *);
  98 static u_char calcShortSum(u_char *);
  99 static int delete(struct fat_descriptor *, cl_t, int, cl_t, int, int);
 100 static int removede(struct fat_descriptor *, u_char *, u_char *,
 101     cl_t, cl_t, cl_t, char *, int);
 102 static int checksize(struct fat_descriptor *, u_char *, struct dosDirEntry *);
 103 static int readDosDirSection(struct fat_descriptor *, struct dosDirEntry *);
 104
 105 /*
 106  * Manage free dosDirEntry structures.
 107  */
 108 static struct dosDirEntry *freede;
 109
 110 static struct dosDirEntry *
 111 newDosDirEntry(void)
 112 {
 113         struct dosDirEntry *de;
 114
 115         if (!(de = freede)) {
 116                 if (!(de = malloc(sizeof *de)))
 117                         return (NULL);
 118         } else
 119                 freede = de->next;
 120         return de;
 121 }
 122
 123 static void
 124 freeDosDirEntry(struct dosDirEntry *de)
 125 {
 126         de->next = freede;
 127         freede = de;
 128 }
 129
 130 /*
 131  * The same for dirTodoNode structures.
 132  */
 133 static struct dirTodoNode *freedt;
 134
 135 static struct dirTodoNode *
 136 newDirTodo(void)
 137 {
 138         struct dirTodoNode *dt;
 139
 140         if (!(dt = freedt)) {
 141                 if (!(dt = malloc(sizeof *dt)))
 142                         return 0;
 143         } else
 144                 freedt = dt->next;
 145         return dt;
 146 }
 147
 148 static void
 149 freeDirTodo(struct dirTodoNode *dt)
 150 {
 151         dt->next = freedt;
 152         freedt = dt;
 153 }
 154
 155 /*
 156  * The stack of unread directories
 157  */
 158 static struct dirTodoNode *pendingDirectories = NULL;
 159
 160 /*
 161  * Return the full pathname for a directory entry.
 162  */
 163 static char *
 164 fullpath(struct dosDirEntry *dir)
 165 {
 166         static char namebuf[MAXPATHLEN + 1];
 167         char *cp, *np;
 168         int nl;
 169
 170         cp = namebuf + sizeof namebuf;
 171         *--cp = '\0';
 172
 173         for(;;) {
 174                 np = dir->lname[0] ? dir->lname : dir->name;
 175                 nl = strlen(np);
 176                 if (cp <= namebuf + 1 + nl) {
 177                         *--cp = '?';
 178                         break;
 179                 }
 180                 cp -= nl;
 181                 memcpy(cp, np, nl);
 182                 dir = dir->parent;
 183                 if (!dir)
 184                         break;
 185                 *--cp = '/';
 186         }
 187
 188         return cp;
 189 }
 190
 191 /*
 192  * Calculate a checksum over an 8.3 alias name
 193  */
 194 static inline u_char
 195 calcShortSum(u_char *p)
 196 {
 197         u_char sum = 0;
 198         int i;
 199
 200         for (i = 0; i < 11; i++) {
 201                 sum = (sum << 7)|(sum >> 1);    /* rotate right */
 202                 sum += p[i];
 203         }
 204
 205         return sum;
 206 }
 207
 208 /*
 209  * Global variables temporarily used during a directory scan
 210  */
 211 static char longName[DOSLONGNAMELEN] = "";
 212 static u_char *buffer = NULL;
 213 static u_char *delbuf = NULL;
 214
 215 static struct dosDirEntry *rootDir;
 216 static struct dosDirEntry *lostDir;
 217
 218 /*
 219  * Init internal state for a new directory scan.
 220  */
 221 int
 222 resetDosDirSection(struct fat_descriptor *fat)
 223 {
 224         int rootdir_size, cluster_size;
 225         int ret = FSOK;
 226         size_t len;
 227         struct bootblock *boot;
 228
 229         boot = fat_get_boot(fat);
 230
 231         rootdir_size = boot->bpbRootDirEnts * 32;
 232         cluster_size = boot->bpbSecPerClust * boot->bpbBytesPerSec;
 233
 234         if ((buffer = malloc(len = MAX(rootdir_size, cluster_size))) == NULL) {
 235                 perr("No space for directory buffer (%zu)", len);
 236                 return FSFATAL;
 237         }
 238
 239         if ((delbuf = malloc(len = cluster_size)) == NULL) {
 240                 free(buffer);
 241                 perr("No space for directory delbuf (%zu)", len);
 242                 return FSFATAL;
 243         }
 244
 245         if ((rootDir = newDosDirEntry()) == NULL) {
 246                 free(buffer);
 247                 free(delbuf);
 248                 perr("No space for directory entry");
 249                 return FSFATAL;
 250         }
 251
 252         memset(rootDir, 0, sizeof *rootDir);
 253         if (boot->flags & FAT32) {
 254                 if (!fat_is_cl_head(fat, boot->bpbRootClust)) {
 255                         pfatal("Root directory doesn't start a cluster chain");
 256                         return FSFATAL;
 257                 }
 258                 rootDir->head = boot->bpbRootClust;
 259         }
 260
 261         return ret;
 262 }
 263
 264 /*
 265  * Cleanup after a directory scan
 266  */
 267 void
 268 finishDosDirSection(void)
 269 {
 270         struct dirTodoNode *p, *np;
 271         struct dosDirEntry *d, *nd;
 272
 273         for (p = pendingDirectories; p; p = np) {
 274                 np = p->next;
 275                 freeDirTodo(p);
 276         }
 277         pendingDirectories = NULL;
 278         for (d = rootDir; d; d = nd) {
 279                 if ((nd = d->child) != NULL) {
 280                         d->child = 0;
 281                         continue;
 282                 }
 283                 if (!(nd = d->next))
 284                         nd = d->parent;
 285                 freeDosDirEntry(d);
 286         }
 287         rootDir = lostDir = NULL;
 288         free(buffer);
 289         free(delbuf);
 290         buffer = NULL;
 291         delbuf = NULL;
 292 }
 293
 294 /*
 295  * Delete directory entries between startcl, startoff and endcl, endoff.
 296  */
 297 static int
 298 delete(struct fat_descriptor *fat, cl_t startcl,
 299     int startoff, cl_t endcl, int endoff, int notlast)
 300 {
 301         u_char *s, *e;
 302         off_t off;
 303         int clsz, fd;
 304         struct bootblock *boot;
 305
 306         boot = fat_get_boot(fat);
 307         fd = fat_get_fd(fat);
 308         clsz = boot->bpbSecPerClust * boot->bpbBytesPerSec;
 309
 310         s = delbuf + startoff;
 311         e = delbuf + clsz;
 312         while (fat_is_valid_cl(fat, startcl)) {
 313                 if (startcl == endcl) {
 314                         if (notlast)
 315                                 break;
 316                         e = delbuf + endoff;
 317                 }
 318                 off = (startcl - CLUST_FIRST) * boot->bpbSecPerClust + boot->FirstCluster;
 319
 320                 off *= boot->bpbBytesPerSec;
 321                 if (lseek(fd, off, SEEK_SET) != off) {
 322                         perr("Unable to lseek to %" PRId64, off);
 323                         return FSFATAL;
 324                 }
 325                 if (read(fd, delbuf, clsz) != clsz) {
 326                         perr("Unable to read directory");
 327                         return FSFATAL;
 328                 }
 329                 while (s < e) {
 330                         *s = SLOT_DELETED;
 331                         s += 32;
 332                 }
 333                 if (lseek(fd, off, SEEK_SET) != off) {
 334                         perr("Unable to lseek to %" PRId64, off);
 335                         return FSFATAL;
 336                 }
 337                 if (write(fd, delbuf, clsz) != clsz) {
 338                         perr("Unable to write directory");
 339                         return FSFATAL;
 340                 }
 341                 if (startcl == endcl)
 342                         break;
 343                 startcl = fat_get_cl_next(fat, startcl);
 344                 s = delbuf;
 345         }
 346         return FSOK;
 347 }
 348
 349 static int
 350 removede(struct fat_descriptor *fat, u_char *start,
 351     u_char *end, cl_t startcl, cl_t endcl, cl_t curcl,
 352     char *path, int type)
 353 {
 354         switch (type) {
 355         case 0:
 356                 pwarn("Invalid long filename entry for %s\n", path);
 357                 break;
 358         case 1:
 359                 pwarn("Invalid long filename entry at end of directory %s\n",
 360                     path);
 361                 break;
 362         case 2:
 363                 pwarn("Invalid long filename entry for volume label\n");
 364                 break;
 365         }
 366         if (ask(0, "Remove")) {
 367                 if (startcl != curcl) {
 368                         if (delete(fat,
 369                                    startcl, start - buffer,
 370                                    endcl, end - buffer,
 371                                    endcl == curcl) == FSFATAL)
 372                                 return FSFATAL;
 373                         start = buffer;
 374                 }
 375                 /* startcl is < CLUST_FIRST for !FAT32 root */
 376                 if ((endcl == curcl) || (startcl < CLUST_FIRST))
 377                         for (; start < end; start += 32)
 378                                 *start = SLOT_DELETED;
 379                 return FSDIRMOD;
 380         }
 381         return FSERROR;
 382 }
 383
 384 /*
 385  * Check an in-memory file entry
 386  */
 387 static int
 388 checksize(struct fat_descriptor *fat, u_char *p, struct dosDirEntry *dir)
 389 {
 390         int ret = FSOK;
 391         size_t physicalSize;
 392         struct bootblock *boot;
 393
 394         boot = fat_get_boot(fat);
 395
 396         /*
 397          * Check size on ordinary files
 398          */
 399         if (dir->head == CLUST_FREE) {
 400                 physicalSize = 0;
 401         } else {
 402                 if (!fat_is_valid_cl(fat, dir->head))
 403                         return FSERROR;
 404                 ret = checkchain(fat, dir->head, &physicalSize);
 405                 /*
 406                  * Upon return, physicalSize would hold the chain length
 407                  * that checkchain() was able to validate, but if the user
 408                  * refused the proposed repair, it would be unsafe to
 409                  * proceed with directory entry fix, so bail out in that
 410                  * case.
 411                  */
 412                 if (ret == FSERROR) {
 413                         return (FSERROR);
 414                 }
 415                 physicalSize *= boot->ClusterSize;
 416         }
 417         if (physicalSize < dir->size) {
 418                 pwarn("size of %s is %u, should at most be %zu\n",
 419                       fullpath(dir), dir->size, physicalSize);
 420                 if (ask(1, "Truncate")) {
 421                         dir->size = physicalSize;
 422                         p[28] = (u_char)physicalSize;
 423                         p[29] = (u_char)(physicalSize >> 8);
 424                         p[30] = (u_char)(physicalSize >> 16);
 425                         p[31] = (u_char)(physicalSize >> 24);
 426                         return FSDIRMOD;
 427                 } else
 428                         return FSERROR;
 429         } else if (physicalSize - dir->size >= boot->ClusterSize) {
 430                 pwarn("%s has too many clusters allocated\n",
 431                       fullpath(dir));
 432                 if (ask(1, "Drop superfluous clusters")) {
 433                         cl_t cl;
 434                         u_int32_t sz, len;
 435
 436                         for (cl = dir->head, len = sz = 0;
 437                             (sz += boot->ClusterSize) < dir->size; len++)
 438                                 cl = fat_get_cl_next(fat, cl);
 439                         clearchain(fat, fat_get_cl_next(fat, cl));
 440                         ret = fat_set_cl_next(fat, cl, CLUST_EOF);
 441                         return (FSFATMOD | ret);
 442                 } else
 443                         return FSERROR;
 444         }
 445         return FSOK;
 446 }
 447
 448 static const u_char dot_name[11]    = ".          ";
 449 static const u_char dotdot_name[11] = "..         ";
 450
 451 /*
 452  * Basic sanity check if the subdirectory have good '.' and '..' entries,
 453  * and they are directory entries.  Further sanity checks are performed
 454  * when we traverse into it.
 455  */
 456 static int
 457 check_subdirectory(struct fat_descriptor *fat, struct dosDirEntry *dir)
 458 {
 459         u_char *buf, *cp;
 460         off_t off;
 461         cl_t cl;
 462         int retval = FSOK;
 463         int fd;
 464         struct bootblock *boot;
 465
 466         boot = fat_get_boot(fat);
 467         fd = fat_get_fd(fat);
 468
 469         cl = dir->head;
 470         if (dir->parent && !fat_is_valid_cl(fat, cl)) {
 471                 return FSERROR;
 472         }
 473
 474         if (!(boot->flags & FAT32) && !dir->parent) {
 475                 off = boot->bpbResSectors + boot->bpbFATs *
 476                         boot->FATsecs;
 477         } else {
 478                 off = (cl - CLUST_FIRST) * boot->bpbSecPerClust + boot->FirstCluster;
 479         }
 480
 481         /*
 482          * We only need to check the first two entries of the directory,
 483          * which is found in the first sector of the directory entry,
 484          * so read in only the first sector.
 485          */
 486         buf = malloc(boot->bpbBytesPerSec);
 487         if (buf == NULL) {
 488                 perr("No space for directory buffer (%u)",
 489                     boot->bpbBytesPerSec);
 490                 return FSFATAL;
 491         }
 492
 493         off *= boot->bpbBytesPerSec;
 494         if (lseek(fd, off, SEEK_SET) != off ||
 495             read(fd, buf, boot->bpbBytesPerSec) != (ssize_t)boot->bpbBytesPerSec) {
 496                 perr("Unable to read directory");
 497                 free(buf);
 498                 return FSFATAL;
 499         }
 500
 501         /*
 502          * Both `.' and `..' must be present and be the first two entries
 503          * and be ATTR_DIRECTORY of a valid subdirectory.
 504          */
 505         cp = buf;
 506         if (memcmp(cp, dot_name, sizeof(dot_name)) != 0 ||
 507             (cp[11] & ATTR_DIRECTORY) != ATTR_DIRECTORY) {
 508                 pwarn("%s: Incorrect `.' for %s.\n", __func__, dir->name);
 509                 retval |= FSERROR;
 510         }
 511         cp += 32;
 512         if (memcmp(cp, dotdot_name, sizeof(dotdot_name)) != 0 ||
 513             (cp[11] & ATTR_DIRECTORY) != ATTR_DIRECTORY) {
 514                 pwarn("%s: Incorrect `..' for %s. \n", __func__, dir->name);
 515                 retval |= FSERROR;
 516         }
 517
 518         free(buf);
 519         return retval;
 520 }
 521
 522 /*
 523  * Read a directory and
 524  *   - resolve long name records
 525  *   - enter file and directory records into the parent's list
 526  *   - push directories onto the todo-stack
 527  */
 528 static int
 529 readDosDirSection(struct fat_descriptor *fat, struct dosDirEntry *dir)
 530 {
 531         struct bootblock *boot;
 532         struct dosDirEntry dirent, *d;
 533         u_char *p, *vallfn, *invlfn, *empty;
 534         off_t off;
 535         int fd, i, j, k, iosize, entries;
 536         bool is_legacyroot;
 537         cl_t cl, valcl = ~0, invcl = ~0, empcl = ~0;
 538         char *t;
 539         u_int lidx = 0;
 540         int shortSum;
 541         int mod = FSOK;
 542         size_t dirclusters;
 543 #define THISMOD 0x8000                  /* Only used within this routine */
 544
 545         boot = fat_get_boot(fat);
 546         fd = fat_get_fd(fat);
 547
 548         cl = dir->head;
 549         if (dir->parent && (!fat_is_valid_cl(fat, cl))) {
 550                 /*
 551                  * Already handled somewhere else.
 552                  */
 553                 return FSOK;
 554         }
 555         shortSum = -1;
 556         vallfn = invlfn = empty = NULL;
 557
 558         /*
 559          * If we are checking the legacy root (for FAT12/FAT16),
 560          * we will operate on the whole directory; otherwise, we
 561          * will operate on one cluster at a time, and also take
 562          * this opportunity to examine the chain.
 563          *
 564          * Derive how many entries we are going to encounter from
 565          * the I/O size.
 566          */
 567         is_legacyroot = (dir->parent == NULL && !(boot->flags & FAT32));
 568         if (is_legacyroot) {
 569                 iosize = boot->bpbRootDirEnts * 32;
 570                 entries = boot->bpbRootDirEnts;
 571         } else {
 572                 iosize = boot->bpbSecPerClust * boot->bpbBytesPerSec;
 573                 entries = iosize / 32;
 574                 mod |= checkchain(fat, dir->head, &dirclusters);
 575         }
 576
 577         do {
 578                 if (is_legacyroot) {
 579                         /*
 580                          * Special case for FAT12/FAT16 root -- read
 581                          * in the whole root directory.
 582                          */
 583                         off = boot->bpbResSectors + boot->bpbFATs *
 584                             boot->FATsecs;
 585                 } else {
 586                         /*
 587                          * Otherwise, read in a cluster of the
 588                          * directory.
 589                          */
 590                         off = (cl - CLUST_FIRST) * boot->bpbSecPerClust + boot->FirstCluster;
 591                 }
 592
 593                 off *= boot->bpbBytesPerSec;
 594                 if (lseek(fd, off, SEEK_SET) != off ||
 595                     read(fd, buffer, iosize) != iosize) {
 596                         perr("Unable to read directory");
 597                         return FSFATAL;
 598                 }
 599
 600                 for (p = buffer, i = 0; i < entries; i++, p += 32) {
 601                         if (dir->fsckflags & DIREMPWARN) {
 602                                 *p = SLOT_EMPTY;
 603                                 continue;
 604                         }
 605
 606                         if (*p == SLOT_EMPTY || *p == SLOT_DELETED) {
 607                                 if (*p == SLOT_EMPTY) {
 608                                         dir->fsckflags |= DIREMPTY;
 609                                         empty = p;
 610                                         empcl = cl;
 611                                 }
 612                                 continue;
 613                         }
 614
 615                         if (dir->fsckflags & DIREMPTY) {
 616                                 if (!(dir->fsckflags & DIREMPWARN)) {
 617                                         pwarn("%s has entries after end of directory\n",
 618                                               fullpath(dir));
 619                                         if (ask(1, "Extend")) {
 620                                                 u_char *q;
 621
 622                                                 dir->fsckflags &= ~DIREMPTY;
 623                                                 if (delete(fat,
 624                                                            empcl, empty - buffer,
 625                                                            cl, p - buffer, 1) == FSFATAL)
 626                                                         return FSFATAL;
 627                                                 q = ((empcl == cl) ? empty : buffer);
 628                                                 assert(q != NULL);
 629                                                 for (; q < p; q += 32)
 630                                                         *q = SLOT_DELETED;
 631                                                 mod |= THISMOD|FSDIRMOD;
 632                                         } else if (ask(0, "Truncate"))
 633                                                 dir->fsckflags |= DIREMPWARN;
 634                                 }
 635                                 if (dir->fsckflags & DIREMPWARN) {
 636                                         *p = SLOT_DELETED;
 637                                         mod |= THISMOD|FSDIRMOD;
 638                                         continue;
 639                                 } else if (dir->fsckflags & DIREMPTY)
 640                                         mod |= FSERROR;
 641                                 empty = NULL;
 642                         }
 643
 644                         if (p[11] == ATTR_WIN95) {
 645                                 if (*p & LRFIRST) {
 646                                         if (shortSum != -1) {
 647                                                 if (!invlfn) {
 648                                                         invlfn = vallfn;
 649                                                         invcl = valcl;
 650                                                 }
 651                                         }
 652                                         memset(longName, 0, sizeof longName);
 653                                         shortSum = p[13];
 654                                         vallfn = p;
 655                                         valcl = cl;
 656                                 } else if (shortSum != p[13]
 657                                            || lidx != (*p & LRNOMASK)) {
 658                                         if (!invlfn) {
 659                                                 invlfn = vallfn;
 660                                                 invcl = valcl;
 661                                         }
 662                                         if (!invlfn) {
 663                                                 invlfn = p;
 664                                                 invcl = cl;
 665                                         }
 666                                         vallfn = NULL;
 667                                 }
 668                                 lidx = *p & LRNOMASK;
 669                                 if (lidx == 0) {
 670                                         pwarn("invalid long name\n");
 671                                         if (!invlfn) {
 672                                                 invlfn = vallfn;
 673                                                 invcl = valcl;
 674                                         }
 675                                         vallfn = NULL;
 676                                         continue;
 677                                 }
 678                                 t = longName + --lidx * 13;
 679                                 for (k = 1; k < 11 && t < longName +
 680                                     sizeof(longName); k += 2) {
 681                                         if (!p[k] && !p[k + 1])
 682                                                 break;
 683                                         *t++ = p[k];
 684                                         /*
 685                                          * Warn about those unusable chars in msdosfs here?     XXX
 686                                          */
 687                                         if (p[k + 1])
 688                                                 t[-1] = '?';
 689                                 }
 690                                 if (k >= 11)
 691                                         for (k = 14; k < 26 && t < longName + sizeof(longName); k += 2) {
 692                                                 if (!p[k] && !p[k + 1])
 693                                                         break;
 694                                                 *t++ = p[k];
 695                                                 if (p[k + 1])
 696                                                         t[-1] = '?';
 697                                         }
 698                                 if (k >= 26)
 699                                         for (k = 28; k < 32 && t < longName + sizeof(longName); k += 2) {
 700                                                 if (!p[k] && !p[k + 1])
 701                                                         break;
 702                                                 *t++ = p[k];
 703                                                 if (p[k + 1])
 704                                                         t[-1] = '?';
 705                                         }
 706                                 if (t >= longName + sizeof(longName)) {
 707                                         pwarn("long filename too long\n");
 708                                         if (!invlfn) {
 709                                                 invlfn = vallfn;
 710                                                 invcl = valcl;
 711                                         }
 712                                         vallfn = NULL;
 713                                 }
 714                                 if (p[26] | (p[27] << 8)) {
 715                                         pwarn("long filename record cluster start != 0\n");
 716                                         if (!invlfn) {
 717                                                 invlfn = vallfn;
 718                                                 invcl = cl;
 719                                         }
 720                                         vallfn = NULL;
 721                                 }
 722                                 continue;       /* long records don't carry further
 723                                                  * information */
 724                         }
 725
 726                         /*
 727                          * This is a standard msdosfs directory entry.
 728                          */
 729                         memset(&dirent, 0, sizeof dirent);
 730
 731                         /*
 732                          * it's a short name record, but we need to know
 733                          * more, so get the flags first.
 734                          */
 735                         dirent.flags = p[11];
 736
 737                         /*
 738                          * Translate from 850 to ISO here               XXX
 739                          */
 740                         for (j = 0; j < 8; j++)
 741                                 dirent.name[j] = p[j];
 742                         dirent.name[8] = '\0';
 743                         for (k = 7; k >= 0 && dirent.name[k] == ' '; k--)
 744                                 dirent.name[k] = '\0';
 745                         if (k < 0 || dirent.name[k] != '\0')
 746                                 k++;
 747                         if (dirent.name[0] == SLOT_E5)
 748                                 dirent.name[0] = 0xe5;
 749
 750                         if (dirent.flags & ATTR_VOLUME) {
 751                                 if (vallfn || invlfn) {
 752                                         mod |= removede(fat,
 753                                                         invlfn ? invlfn : vallfn, p,
 754                                                         invlfn ? invcl : valcl, -1, 0,
 755                                                         fullpath(dir), 2);
 756                                         vallfn = NULL;
 757                                         invlfn = NULL;
 758                                 }
 759                                 continue;
 760                         }
 761
 762                         if (p[8] != ' ')
 763                                 dirent.name[k++] = '.';
 764                         for (j = 0; j < 3; j++)
 765                                 dirent.name[k++] = p[j+8];
 766                         dirent.name[k] = '\0';
 767                         for (k--; k >= 0 && dirent.name[k] == ' '; k--)
 768                                 dirent.name[k] = '\0';
 769
 770                         if (vallfn && shortSum != calcShortSum(p)) {
 771                                 if (!invlfn) {
 772                                         invlfn = vallfn;
 773                                         invcl = valcl;
 774                                 }
 775                                 vallfn = NULL;
 776                         }
 777                         dirent.head = p[26] | (p[27] << 8);
 778                         if (boot->ClustMask == CLUST32_MASK)
 779                                 dirent.head |= (p[20] << 16) | (p[21] << 24);
 780                         dirent.size = p[28] | (p[29] << 8) | (p[30] << 16) | (p[31] << 24);
 781                         if (vallfn) {
 782                                 strlcpy(dirent.lname, longName,
 783                                     sizeof(dirent.lname));
 784                                 longName[0] = '\0';
 785                                 shortSum = -1;
 786                         }
 787
 788                         dirent.parent = dir;
 789                         dirent.next = dir->child;
 790
 791                         if (invlfn) {
 792                                 mod |= k = removede(fat,
 793                                                     invlfn, vallfn ? vallfn : p,
 794                                                     invcl, vallfn ? valcl : cl, cl,
 795                                                     fullpath(&dirent), 0);
 796                                 if (mod & FSFATAL)
 797                                         return FSFATAL;
 798                                 if (vallfn
 799                                     ? (valcl == cl && vallfn != buffer)
 800                                     : p != buffer)
 801                                         if (k & FSDIRMOD)
 802                                                 mod |= THISMOD;
 803                         }
 804
 805                         vallfn = NULL; /* not used any longer */
 806                         invlfn = NULL;
 807
 808                         /*
 809                          * Check if the directory entry is sane.
 810                          *
 811                          * '.' and '..' are skipped, their sanity is
 812                          * checked somewhere else.
 813                          *
 814                          * For everything else, check if we have a new,
 815                          * valid cluster chain (beginning of a file or
 816                          * directory that was never previously claimed
 817                          * by another file) when it's a non-empty file
 818                          * or a directory. The sanity of the cluster
 819                          * chain is checked at a later time when we
 820                          * traverse into the directory, or examine the
 821                          * file's directory entry.
 822                          *
 823                          * The only possible fix is to delete the entry
 824                          * if it's a directory; for file, we have to
 825                          * truncate the size to 0.
 826                          */
 827                         if (!(dirent.flags & ATTR_DIRECTORY) ||
 828                             (strcmp(dirent.name, ".") != 0 &&
 829                             strcmp(dirent.name, "..") != 0)) {
 830                                 if ((dirent.size != 0 || (dirent.flags & ATTR_DIRECTORY)) &&
 831                                     ((!fat_is_valid_cl(fat, dirent.head) ||
 832                                     !fat_is_cl_head(fat, dirent.head)))) {
 833                                         if (!fat_is_valid_cl(fat, dirent.head)) {
 834                                                 pwarn("%s starts with cluster out of range(%u)\n",
 835                                                     fullpath(&dirent),
 836                                                     dirent.head);
 837                                         } else {
 838                                                 pwarn("%s doesn't start a new cluster chain\n",
 839                                                     fullpath(&dirent));
 840                                         }
 841
 842                                         if (dirent.flags & ATTR_DIRECTORY) {
 843                                                 if (ask(0, "Remove")) {
 844                                                         *p = SLOT_DELETED;
 845                                                         mod |= THISMOD|FSDIRMOD;
 846                                                 } else
 847                                                         mod |= FSERROR;
 848                                                 continue;
 849                                         } else {
 850                                                 if (ask(1, "Truncate")) {
 851                                                         p[28] = p[29] = p[30] = p[31] = 0;
 852                                                         p[26] = p[27] = 0;
 853                                                         if (boot->ClustMask == CLUST32_MASK)
 854                                                                 p[20] = p[21] = 0;
 855                                                         dirent.size = 0;
 856                                                         dirent.head = 0;
 857                                                         mod |= THISMOD|FSDIRMOD;
 858                                                 } else
 859                                                         mod |= FSERROR;
 860                                         }
 861                                 }
 862                         }
 863                         if (dirent.flags & ATTR_DIRECTORY) {
 864                                 /*
 865                                  * gather more info for directories
 866                                  */
 867                                 struct dirTodoNode *n;
 868
 869                                 if (dirent.size) {
 870                                         pwarn("Directory %s has size != 0\n",
 871                                               fullpath(&dirent));
 872                                         if (ask(1, "Correct")) {
 873                                                 p[28] = p[29] = p[30] = p[31] = 0;
 874                                                 dirent.size = 0;
 875                                                 mod |= THISMOD|FSDIRMOD;
 876                                         } else
 877                                                 mod |= FSERROR;
 878                                 }
 879                                 /*
 880                                  * handle `.' and `..' specially
 881                                  */
 882                                 if (strcmp(dirent.name, ".") == 0) {
 883                                         if (dirent.head != dir->head) {
 884                                                 pwarn("`.' entry in %s has incorrect start cluster\n",
 885                                                       fullpath(dir));
 886                                                 if (ask(1, "Correct")) {
 887                                                         dirent.head = dir->head;
 888                                                         p[26] = (u_char)dirent.head;
 889                                                         p[27] = (u_char)(dirent.head >> 8);
 890                                                         if (boot->ClustMask == CLUST32_MASK) {
 891                                                                 p[20] = (u_char)(dirent.head >> 16);
 892                                                                 p[21] = (u_char)(dirent.head >> 24);
 893                                                         }
 894                                                         mod |= THISMOD|FSDIRMOD;
 895                                                 } else
 896                                                         mod |= FSERROR;
 897                                         }
 898                                         continue;
 899                                 } else if (strcmp(dirent.name, "..") == 0) {
 900                                         if (dir->parent) {              /* XXX */
 901                                                 if (!dir->parent->parent) {
 902                                                         if (dirent.head) {
 903                                                                 pwarn("`..' entry in %s has non-zero start cluster\n",
 904                                                                       fullpath(dir));
 905                                                                 if (ask(1, "Correct")) {
 906                                                                         dirent.head = 0;
 907                                                                         p[26] = p[27] = 0;
 908                                                                         if (boot->ClustMask == CLUST32_MASK)
 909                                                                                 p[20] = p[21] = 0;
 910                                                                         mod |= THISMOD|FSDIRMOD;
 911                                                                 } else
 912                                                                         mod |= FSERROR;
 913                                                         }
 914                                                 } else if (dirent.head != dir->parent->head) {
 915                                                         pwarn("`..' entry in %s has incorrect start cluster\n",
 916                                                               fullpath(dir));
 917                                                         if (ask(1, "Correct")) {
 918                                                                 dirent.head = dir->parent->head;
 919                                                                 p[26] = (u_char)dirent.head;
 920                                                                 p[27] = (u_char)(dirent.head >> 8);
 921                                                                 if (boot->ClustMask == CLUST32_MASK) {
 922                                                                         p[20] = (u_char)(dirent.head >> 16);
 923                                                                         p[21] = (u_char)(dirent.head >> 24);
 924                                                                 }
 925                                                                 mod |= THISMOD|FSDIRMOD;
 926                                                         } else
 927                                                                 mod |= FSERROR;
 928                                                 }
 929                                         }
 930                                         continue;
 931                                 } else {
 932                                         /*
 933                                          * Only one directory entry can point
 934                                          * to dir->head, it's '.'.
 935                                          */
 936                                         if (dirent.head == dir->head) {
 937                                                 pwarn("%s entry in %s has incorrect start cluster\n",
 938                                                                 dirent.name, fullpath(dir));
 939                                                 if (ask(1, "Remove")) {
 940                                                         *p = SLOT_DELETED;
 941                                                         mod |= THISMOD|FSDIRMOD;
 942                                                 } else
 943                                                         mod |= FSERROR;
 944                                                 continue;
 945                                         } else if ((check_subdirectory(fat,
 946                                             &dirent) & FSERROR) == FSERROR) {
 947                                                 /*
 948                                                  * A subdirectory should have
 949                                                  * a dot (.) entry and a dot-dot
 950                                                  * (..) entry of ATTR_DIRECTORY,
 951                                                  * we will inspect further when
 952                                                  * traversing into it.
 953                                                  */
 954                                                 if (ask(1, "Remove")) {
 955                                                         *p = SLOT_DELETED;
 956                                                         mod |= THISMOD|FSDIRMOD;
 957                                                 } else
 958                                                         mod |= FSERROR;
 959                                                 continue;
 960                                         }
 961                                 }
 962
 963                                 /* create directory tree node */
 964                                 if (!(d = newDosDirEntry())) {
 965                                         perr("No space for directory");
 966                                         return FSFATAL;
 967                                 }
 968                                 memcpy(d, &dirent, sizeof(struct dosDirEntry));
 969                                 /* link it into the tree */
 970                                 dir->child = d;
 971
 972                                 /* Enter this directory into the todo list */
 973                                 if (!(n = newDirTodo())) {
 974                                         perr("No space for todo list");
 975                                         return FSFATAL;
 976                                 }
 977                                 n->next = pendingDirectories;
 978                                 n->dir = d;
 979                                 pendingDirectories = n;
 980                         } else {
 981                                 mod |= k = checksize(fat, p, &dirent);
 982                                 if (k & FSDIRMOD)
 983                                         mod |= THISMOD;
 984                         }
 985                         boot->NumFiles++;
 986                 }
 987
 988                 if (is_legacyroot) {
 989                         /*
 990                          * Don't bother to write back right now because
 991                          * we may continue to make modification to the
 992                          * non-FAT32 root directory below.
 993                          */
 994                         break;
 995                 } else if (mod & THISMOD) {
 996                         if (lseek(fd, off, SEEK_SET) != off
 997                             || write(fd, buffer, iosize) != iosize) {
 998                                 perr("Unable to write directory");
 999                                 return FSFATAL;
1000                         }
1001                         mod &= ~THISMOD;
1002                 }
1003         } while (fat_is_valid_cl(fat, (cl = fat_get_cl_next(fat, cl))));
1004         if (invlfn || vallfn)
1005                 mod |= removede(fat,
1006                                 invlfn ? invlfn : vallfn, p,
1007                                 invlfn ? invcl : valcl, -1, 0,
1008                                 fullpath(dir), 1);
1009
1010         /*
1011          * The root directory of non-FAT32 filesystems is in a special
1012          * area and may have been modified above removede() without
1013          * being written out.
1014          */
1015         if ((mod & FSDIRMOD) && is_legacyroot) {
1016                 if (lseek(fd, off, SEEK_SET) != off
1017                     || write(fd, buffer, iosize) != iosize) {
1018                         perr("Unable to write directory");
1019                         return FSFATAL;
1020                 }
1021                 mod &= ~THISMOD;
1022         }
1023         return mod & ~THISMOD;
1024 }
1025
1026 int
1027 handleDirTree(struct fat_descriptor *fat)
1028 {
1029         int mod;
1030
1031         mod = readDosDirSection(fat, rootDir);
1032         if (mod & FSFATAL)
1033                 return FSFATAL;
1034
1035         /*
1036          * process the directory todo list
1037          */
1038         while (pendingDirectories) {
1039                 struct dosDirEntry *dir = pendingDirectories->dir;
1040                 struct dirTodoNode *n = pendingDirectories->next;
1041
1042                 /*
1043                  * remove TODO entry now, the list might change during
1044                  * directory reads
1045                  */
1046                 freeDirTodo(pendingDirectories);
1047                 pendingDirectories = n;
1048
1049                 /*
1050                  * handle subdirectory
1051                  */
1052                 mod |= readDosDirSection(fat, dir);
1053                 if (mod & FSFATAL)
1054                         return FSFATAL;
1055         }
1056
1057         return mod;
1058 }
1059
1060 /*
1061  * Try to reconnect a FAT chain into dir
1062  */
1063 static u_char *lfbuf;
1064 static cl_t lfcl;
1065 static off_t lfoff;
1066
1067 int
1068 reconnect(struct fat_descriptor *fat, cl_t head, size_t length)
1069 {
1070         struct bootblock *boot = fat_get_boot(fat);
1071         struct dosDirEntry d;
1072         int len, dosfs;
1073         u_char *p;
1074
1075         dosfs = fat_get_fd(fat);
1076
1077         if (!ask(1, "Reconnect"))
1078                 return FSERROR;
1079
1080         if (!lostDir) {
1081                 for (lostDir = rootDir->child; lostDir; lostDir = lostDir->next) {
1082                         if (!strcmp(lostDir->name, LOSTDIR))
1083                                 break;
1084                 }
1085                 if (!lostDir) {         /* Create LOSTDIR?              XXX */
1086                         pwarn("No %s directory\n", LOSTDIR);
1087                         return FSERROR;
1088                 }
1089         }
1090         if (!lfbuf) {
1091                 lfbuf = malloc(boot->ClusterSize);
1092                 if (!lfbuf) {
1093                         perr("No space for buffer");
1094                         return FSFATAL;
1095                 }
1096                 p = NULL;
1097         } else
1098                 p = lfbuf;
1099         while (1) {
1100                 if (p)
1101                         for (; p < lfbuf + boot->ClusterSize; p += 32)
1102                                 if (*p == SLOT_EMPTY
1103                                     || *p == SLOT_DELETED)
1104                                         break;
1105                 if (p && p < lfbuf + boot->ClusterSize)
1106                         break;
1107                 lfcl = p ? fat_get_cl_next(fat, lfcl) : lostDir->head;
1108                 if (lfcl < CLUST_FIRST || lfcl >= boot->NumClusters) {
1109                         /* Extend LOSTDIR?                              XXX */
1110                         pwarn("No space in %s\n", LOSTDIR);
1111                         lfcl = (lostDir->head < boot->NumClusters) ? lostDir->head : 0;
1112                         return FSERROR;
1113                 }
1114                 lfoff = (lfcl - CLUST_FIRST) * boot->ClusterSize
1115                     + boot->FirstCluster * boot->bpbBytesPerSec;
1116
1117                 if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
1118                     || (size_t)read(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
1119                         perr("could not read LOST.DIR");
1120                         return FSFATAL;
1121                 }
1122                 p = lfbuf;
1123         }
1124
1125         boot->NumFiles++;
1126         /* Ensure uniqueness of entry here!                             XXX */
1127         memset(&d, 0, sizeof d);
1128         /* worst case -1 = 4294967295, 10 digits */
1129         len = snprintf(d.name, sizeof(d.name), "%u", head);
1130         d.flags = 0;
1131         d.head = head;
1132         d.size = length * boot->ClusterSize;
1133
1134         memcpy(p, d.name, len);
1135         memset(p + len, ' ', 11 - len);
1136         memset(p + 11, 0, 32 - 11);
1137         p[26] = (u_char)d.head;
1138         p[27] = (u_char)(d.head >> 8);
1139         if (boot->ClustMask == CLUST32_MASK) {
1140                 p[20] = (u_char)(d.head >> 16);
1141                 p[21] = (u_char)(d.head >> 24);
1142         }
1143         p[28] = (u_char)d.size;
1144         p[29] = (u_char)(d.size >> 8);
1145         p[30] = (u_char)(d.size >> 16);
1146         p[31] = (u_char)(d.size >> 24);
1147         if (lseek(dosfs, lfoff, SEEK_SET) != lfoff
1148             || (size_t)write(dosfs, lfbuf, boot->ClusterSize) != boot->ClusterSize) {
1149                 perr("could not write LOST.DIR");
1150                 return FSFATAL;
1151         }
1152         return FSDIRMOD;
1153 }
1154
1155 void
1156 finishlf(void)
1157 {
1158         if (lfbuf)
1159                 free(lfbuf);
1160         lfbuf = NULL;
1161 }