reactos/ntoskrnl/fsrtl/dbcsname.c

   1 /*
   2  * PROJECT:         ReactOS Kernel
   3  * LICENSE:         GPL - See COPYING in the top level directory
   4  * FILE:            ntoskrnl/fsrtl/name.c
   5  * PURPOSE:         Provides DBCS parsing and other support routines for FSDs
   6  * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
   7  *                  Pierre Schweitzer (pierre.schweitzer@reactos.org)
   8  */
   9
  10 /* INCLUDES ******************************************************************/
  11
  12 #include <ntoskrnl.h>
  13 #define NDEBUG
  14 #include <debug.h>
  15
  16 /* PUBLIC FUNCTIONS **********************************************************/
  17
  18 /*++
  19  * @name FsRtlDissectDbcs
  20  * @implemented
  21  *
  22  * Dissects a given path name into first and remaining part.
  23  *
  24  * @param Name
  25  *        ANSI string to dissect.
  26  *
  27  * @param FirstPart
  28  *        Pointer to user supplied ANSI_STRING, that will later point
  29  *        to the first part of the original name.
  30  *
  31  * @param RemainingPart
  32  *        Pointer to user supplied ANSI_STRING, that will later point
  33  *        to the remaining part of the original name.
  34  *
  35  * @return None
  36  *
  37  * @remarks Example:
  38  *          Name:           \test1\test2\test3
  39  *          FirstPart:      test1
  40  *          RemainingPart:  test2\test3
  41  *
  42  *--*/
  43 VOID
  44 NTAPI
  45 FsRtlDissectDbcs(IN ANSI_STRING Name,
  46                  OUT PANSI_STRING FirstPart,
  47                  OUT PANSI_STRING RemainingPart)
  48 {
  49     USHORT FirstPosition, i;
  50     USHORT SkipFirstSlash = 0;
  51     PAGED_CODE();
  52
  53     /* Zero the strings before continuing */
  54     RtlZeroMemory(FirstPart, sizeof(ANSI_STRING));
  55     RtlZeroMemory(RemainingPart, sizeof(ANSI_STRING));
  56
  57     /* Just quit if the string is empty */
  58     if (!Name.Length) return;
  59
  60     /* Find first backslash */
  61     FirstPosition = Name.Length;
  62     for (i = 0; i < Name.Length; i++)
  63     {
  64         /* First make sure the character it's not the Lead DBCS */
  65         if (FsRtlIsLeadDbcsCharacter(Name.Buffer[i]))
  66         {
  67             i++;
  68         }
  69         /* If we found one... */
  70         else if (Name.Buffer[i] == '\\')
  71         {
  72             /* If it begins string, just notice it and continue */
  73             if (i == 0)
  74             {
  75                 SkipFirstSlash = 1;
  76             }
  77             else
  78             {
  79                 /* Else, save its position and break out of the loop */
  80                 FirstPosition = i;
  81                 break;
  82             }
  83         }
  84     }
  85
  86     /* Set up the first result string */
  87     FirstPart->Buffer = Name.Buffer + SkipFirstSlash;
  88     FirstPart->Length = (FirstPosition - SkipFirstSlash);
  89     FirstPart->MaximumLength = FirstPart->Length;
  90
  91     /* And second one, if necessary */
  92     if (FirstPosition < (Name.Length))
  93     {
  94         RemainingPart->Buffer = Name.Buffer + FirstPosition + 1;
  95         RemainingPart->Length = Name.Length - (FirstPosition + 1);
  96         RemainingPart->MaximumLength = RemainingPart->Length;
  97     }
  98 }
  99
 100 /*++
 101  * @name FsRtlDoesDbcsContainWildCards
 102  * @implemented
 103  *
 104  * Returns TRUE if the given DbcsName contains wildcards such as *, ?,
 105  * ANSI_DOS_STAR, ANSI_DOS_DOT, and ANSI_DOS_QM
 106  *
 107  * @param Name
 108  *        The Name to check
 109  *
 110  * @return TRUE if there are wildcards, FALSE otherwise
 111  *
 112  * @remarks None
 113  *
 114  *--*/
 115 BOOLEAN
 116 NTAPI
 117 FsRtlDoesDbcsContainWildCards(IN PANSI_STRING Name)
 118 {
 119     USHORT i;
 120     PAGED_CODE();
 121
 122     /* Check every character */
 123     for (i = 0; i < Name->Length; i++)
 124     {
 125         /* First make sure it's not the Lead DBCS */
 126         if (FsRtlIsLeadDbcsCharacter(Name->Buffer[i]))
 127         {
 128             i++;
 129         }
 130         else if (FsRtlIsAnsiCharacterWild(Name->Buffer[i]))
 131         {
 132             /* Now return if it has a wildcard */
 133             return TRUE;
 134         }
 135     }
 136
 137     /* We didn't return above...so none found */
 138     return FALSE;
 139 }
 140
 141 /*++
 142  * @name FsRtlIsDbcsInExpression
 143  * @implemented
 144  *
 145  * Check if the Name string is in the Expression string.
 146  *
 147  * @param Expression
 148  *        The string in which we've to find Name. It can contains wildcards
 149  *
 150  * @param Name
 151  *        The string to find. It cannot contain wildcards.
 152  *
 153  * @return TRUE if Name is found in Expression, FALSE otherwise
 154  *
 155  * @remarks
 156  *
 157  *--*/
 158 BOOLEAN
 159 NTAPI
 160 FsRtlIsDbcsInExpression(IN PANSI_STRING Expression,
 161                         IN PANSI_STRING Name)
 162 {
 163     SHORT StarFound = -1;
 164     PUSHORT BackTracking = NULL;
 165     USHORT ExpressionPosition = 0, NamePosition = 0, MatchingChars;
 166     BOOLEAN BeyondName;
 167     PAGED_CODE();
 168
 169     ASSERT(Name->Length);
 170     ASSERT(Expression->Length);
 171     ASSERT(!FsRtlDoesDbcsContainWildCards(Name));
 172
 173     while (NamePosition < Name->Length && ExpressionPosition < Expression->Length)
 174     {
 175         /* Basic check to test if chars are equal */
 176         if ((Expression->Buffer[ExpressionPosition] == Name->Buffer[NamePosition]))
 177         {
 178             NamePosition++;
 179             ExpressionPosition++;
 180         }
 181         /* Check cases that eat one char */
 182         else if ((Expression->Buffer[ExpressionPosition] == '?') || (Expression->Buffer[ExpressionPosition] == ANSI_DOS_QM) ||
 183                  (Expression->Buffer[ExpressionPosition] == ANSI_DOS_DOT && Name->Buffer[NamePosition] == '.'))
 184         {
 185             NamePosition++;
 186             ExpressionPosition++;
 187         }
 188         /* Test star */
 189         else if (Expression->Buffer[ExpressionPosition] == '*')
 190         {
 191             /* Skip contigous stars */
 192             while (ExpressionPosition + 1 < Expression->Length && Expression->Buffer[ExpressionPosition + 1] == '*')
 193             {
 194                 ExpressionPosition++;
 195             }
 196
 197             /* Save star position */
 198             if (!BackTracking)
 199             {
 200                 BackTracking = ExAllocatePoolWithTag(PagedPool | POOL_RAISE_IF_ALLOCATION_FAILURE,
 201                                                      Expression->Length * sizeof(USHORT), 'nrSF');
 202             }
 203             BackTracking[++StarFound] = ExpressionPosition++;
 204
 205             /* If star is at the end, then eat all rest and leave */
 206             if (ExpressionPosition == Expression->Length)
 207             {
 208                 NamePosition = Name->Length;
 209                 break;
 210             }
 211             /* Allow null matching */
 212             else if (Expression->Buffer[ExpressionPosition] != '?' &&
 213                      Expression->Buffer[ExpressionPosition] != Name->Buffer[NamePosition])
 214             {
 215                 NamePosition++;
 216             }
 217         }
 218         /* Check DOS_STAR */
 219         else if (Expression->Buffer[ExpressionPosition] == ANSI_DOS_STAR)
 220         {
 221             MatchingChars = NamePosition;
 222             while (MatchingChars < Name->Length)
 223             {
 224                 if (Name->Buffer[MatchingChars] == '.')
 225                 {
 226                     NamePosition = MatchingChars + 1;
 227                 }
 228                 MatchingChars++;
 229             }
 230             ExpressionPosition++;
 231         }
 232         /* Check DOS_DOT */
 233         else if (Expression->Buffer[ExpressionPosition] == DOS_DOT)
 234         {
 235             /* First try to find whether we are beyond last dot (beyond name) */
 236             BeyondName = TRUE;
 237             MatchingChars = NamePosition + 1;
 238             while (MatchingChars < Name->Length)
 239             {
 240                 if (Name->Buffer[MatchingChars] == '.')
 241                 {
 242                     BeyondName = FALSE;
 243                     break;
 244                 }
 245                 MatchingChars++;
 246             }
 247
 248             /* If we are beyond name, we null match */
 249             if (BeyondName)
 250             {
 251                 ExpressionPosition++;
 252                 continue;
 253             }
 254             /* If not, we only match a dot */
 255             else if (Name->Buffer[NamePosition] == '.')
 256             {
 257                 NamePosition++;
 258                 ExpressionPosition++;
 259                 continue;
 260             }
 261             /* Otherwise, fail */
 262             else
 263             {
 264                 break;
 265             }
 266         }
 267         /* If nothing match, try to backtrack */
 268         else if (StarFound >= 0)
 269         {
 270             ExpressionPosition = BackTracking[StarFound--];
 271         }
 272         /* Otherwise, fail */
 273         else
 274         {
 275             break;
 276         }
 277
 278         /* Under certain circumstances, expression is over, but name isn't
 279          * and we can backtrack, then, backtrack */
 280         if (ExpressionPosition == Expression->Length &&
 281             NamePosition != Name->Length && StarFound >= 0)
 282         {
 283             ExpressionPosition = BackTracking[StarFound--];
 284         }
 285     }
 286     /* If we have nullable matching wc at the end of the string, eat them */
 287     if (ExpressionPosition != Expression->Length && NamePosition == Name->Length)
 288     {
 289         while (ExpressionPosition < Expression->Length)
 290         {
 291             if (Expression->Buffer[ExpressionPosition] != ANSI_DOS_DOT &&
 292                 Expression->Buffer[ExpressionPosition] != '*' &&
 293                 Expression->Buffer[ExpressionPosition] != ANSI_DOS_STAR)
 294             {
 295                 break;
 296             }
 297             ExpressionPosition++;
 298         }
 299     }
 300
 301     if (BackTracking)
 302     {
 303         ExFreePoolWithTag(BackTracking, 'nrSF');
 304     }
 305
 306     return (ExpressionPosition == Expression->Length && NamePosition == Name->Length);
 307 }
 308
 309 /*++
 310  * @name FsRtlIsFatDbcsLegal
 311  * @implemented
 312  *
 313  * Returns TRUE if the given DbcsName is a valid FAT filename (in 8.3)
 314  *
 315  * @param DbcsName
 316  *        The filename to check. It can also contains pathname.
 317  *
 318  * @param WildCardsPermissible
 319  *        If this is set to FALSE and if filename contains wildcard, the function
 320  *        will fail
 321  *
 322  * @param PathNamePermissible
 323  *        If this is set to FALSE and if the filename comes with a pathname, the
 324  *        function will fail
 325  *
 326  * @param LeadingBackslashPermissible
 327  *        If this is set to FALSE and if the filename starts with a backslash, the
 328  *        function will fail
 329  *
 330  * @return TRUE if the DbcsName is legal, FALSE otherwise
 331  *
 332  * @remarks None
 333  *
 334  *--*/
 335 BOOLEAN
 336 NTAPI
 337 FsRtlIsFatDbcsLegal(IN ANSI_STRING DbcsName,
 338                     IN BOOLEAN WildCardsPermissible,
 339                     IN BOOLEAN PathNamePermissible,
 340                     IN BOOLEAN LeadingBackslashPermissible)
 341 {
 342     ANSI_STRING FirstPart, RemainingPart, Name;
 343     BOOLEAN LastDot;
 344     USHORT i;
 345     PAGED_CODE();
 346
 347     /* Just quit if the string is empty */
 348     if (!DbcsName.Length)
 349         return FALSE;
 350
 351     /* DbcsName wasn't supposed to be started with \ */
 352     if (!LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 353         return FALSE;
 354     /* DbcsName was allowed to be started with \, but now, remove it */
 355     else if (LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 356     {
 357         DbcsName.Buffer = DbcsName.Buffer + 1;
 358         DbcsName.Length = DbcsName.Length - 1;
 359         DbcsName.MaximumLength = DbcsName.MaximumLength - 1;
 360     }
 361
 362     /* Extract first part of the DbcsName to work on */
 363     FsRtlDissectDbcs(DbcsName, &FirstPart, &RemainingPart);
 364     while (FirstPart.Length > 0)
 365     {
 366         /* Reset dots count */
 367         LastDot = FALSE;
 368
 369         /* Accept special filename if wildcards are allowed */
 370         if (WildCardsPermissible && (FirstPart.Length == 1 || FirstPart.Length == 2) && FirstPart.Buffer[0] == '.')
 371         {
 372             if (FirstPart.Length == 2)
 373             {
 374                 if (FirstPart.Buffer[1] == '.')
 375                 {
 376                     goto EndLoop;
 377                 }
 378             }
 379             else
 380             {
 381                 goto EndLoop;
 382             }
 383         }
 384
 385         /* Filename must be 8.3 filename */
 386         if (FirstPart.Length < 3 || FirstPart.Length > 12)
 387             return FALSE;
 388
 389         /* Now, we will parse the filename to find everything bad in */
 390         for (i = 0; i < FirstPart.Length; i++)
 391         {
 392             /* First make sure the character it's not the Lead DBCS */
 393             if (FsRtlIsLeadDbcsCharacter(FirstPart.Buffer[i]))
 394             {
 395                 if (i == (FirstPart.Length) - 1)
 396                     return FALSE;
 397                 i++;
 398             }
 399             /* Then check for bad characters */
 400             else if (!FsRtlIsAnsiCharacterLegalFat(FirstPart.Buffer[i], WildCardsPermissible))
 401             {
 402                 return FALSE;
 403             }
 404             else if (FirstPart.Buffer[i] == '.')
 405             {
 406                 /* Filename can only contain one dot */
 407                 if (LastDot)
 408                     return FALSE;
 409
 410                 LastDot = TRUE;
 411
 412                 /* We mustn't have spaces before dot or at the end of the filename
 413                  * and no dot at the beginning of the filename */
 414                 if ((i == (FirstPart.Length) - 1) || i == 0)
 415                     return FALSE;
 416
 417                 if (i > 0)
 418                     if (FirstPart.Buffer[i - 1] == ' ')
 419                         return FALSE;
 420
 421                 /* Filename must be 8.3 filename and not 3.8 filename */
 422                 if ((FirstPart.Length - 1) - i > 3)
 423                     return FALSE;
 424             }
 425         }
 426
 427         /* Filename mustn't finish with a space */
 428         if (FirstPart.Buffer[FirstPart.Length - 1] == ' ')
 429             return FALSE;
 430
 431         EndLoop:
 432         /* Preparing next loop */
 433         Name.Buffer = RemainingPart.Buffer;
 434         Name.Length = RemainingPart.Length;
 435         Name.MaximumLength = RemainingPart.MaximumLength;
 436
 437         /* Call once again our dissect function */
 438         FsRtlDissectDbcs(Name, &FirstPart, &RemainingPart);
 439
 440         /* We found a pathname, it wasn't allowed */
 441         if (FirstPart.Length > 0 && !PathNamePermissible)
 442             return FALSE;
 443     }
 444     return TRUE;
 445 }
 446
 447 /*++
 448  * @name FsRtlIsHpfsDbcsLegal
 449  * @implemented
 450  *
 451  * Returns TRUE if the given DbcsName is a valid HPFS filename
 452  *
 453  * @param DbcsName
 454  *        The filename to check. It can also contains pathname.
 455  *
 456  * @param WildCardsPermissible
 457  *        If this is set to FALSE and if filename contains wildcard, the function
 458  *        will fail
 459  *
 460  * @param PathNamePermissible
 461  *        If this is set to FALSE and if the filename comes with a pathname, the
 462  *        function will fail
 463  *
 464  * @param LeadingBackslashPermissible
 465  *        If this is set to FALSE and if the filename starts with a backslash, the
 466  *        function will fail
 467  *
 468  * @return TRUE if the DbcsName is legal, FALSE otherwise
 469  *
 470  * @remarks None
 471  *
 472  *--*/
 473 BOOLEAN
 474 NTAPI
 475 FsRtlIsHpfsDbcsLegal(IN ANSI_STRING DbcsName,
 476                      IN BOOLEAN WildCardsPermissible,
 477                      IN BOOLEAN PathNamePermissible,
 478                      IN BOOLEAN LeadingBackslashPermissible)
 479 {
 480     ANSI_STRING FirstPart, RemainingPart, Name;
 481     USHORT i;
 482     PAGED_CODE();
 483
 484     /* Just quit if the string is empty */
 485     if (!DbcsName.Length)
 486         return FALSE;
 487
 488     /* DbcsName wasn't supposed to be started with \ */
 489     if (!LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 490         return FALSE;
 491     /* DbcsName was allowed to be started with \, but now, remove it */
 492     else if (LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 493     {
 494         DbcsName.Buffer = DbcsName.Buffer + 1;
 495         DbcsName.Length = DbcsName.Length - 1;
 496         DbcsName.MaximumLength = DbcsName.MaximumLength - 1;
 497     }
 498
 499     /* Extract first part of the DbcsName to work on */
 500     FsRtlDissectDbcs(DbcsName, &FirstPart, &RemainingPart);
 501     while (FirstPart.Length > 0)
 502     {
 503         /* Accept special filename if wildcards are allowed */
 504         if (WildCardsPermissible && (FirstPart.Length == 1 || FirstPart.Length == 2) && FirstPart.Buffer[0] == '.')
 505         {
 506             if (FirstPart.Length == 2)
 507             {
 508                 if (FirstPart.Buffer[1] == '.')
 509                 {
 510                     goto EndLoop;
 511                 }
 512             }
 513             else
 514             {
 515                 goto EndLoop;
 516             }
 517         }
 518
 519         /* Filename must be 255 bytes maximum */
 520         if (FirstPart.Length > 255)
 521             return FALSE;
 522
 523         /* Now, we will parse the filename to find everything bad in */
 524         for (i = 0; i < FirstPart.Length; i++)
 525         {
 526             /* First make sure the character it's not the Lead DBCS */
 527             if (FsRtlIsLeadDbcsCharacter(FirstPart.Buffer[i]))
 528             {
 529                 if (i == (FirstPart.Length) - 1)
 530                     return FALSE;
 531                 i++;
 532             }
 533             /* Then check for bad characters */
 534             else if (!FsRtlIsAnsiCharacterLegalHpfs(FirstPart.Buffer[i], WildCardsPermissible))
 535             {
 536                 return FALSE;
 537             }
 538         }
 539
 540         /* Filename mustn't finish with a space or a dot */
 541         if ((FirstPart.Buffer[FirstPart.Length - 1] == ' ') ||
 542             (FirstPart.Buffer[FirstPart.Length - 1] == '.'))
 543             return FALSE;
 544
 545         EndLoop:
 546         /* Preparing next loop */
 547         Name.Buffer = RemainingPart.Buffer;
 548         Name.Length = RemainingPart.Length;
 549         Name.MaximumLength = RemainingPart.MaximumLength;
 550
 551         /* Call once again our dissect function */
 552         FsRtlDissectDbcs(Name, &FirstPart, &RemainingPart);
 553
 554         /* We found a pathname, it wasn't allowed */
 555         if (FirstPart.Length > 0 && !PathNamePermissible)
 556             return FALSE;
 557     }
 558     return TRUE;
 559 }