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     PAGED_CODE();
 167
 168     ASSERT(Name->Length);
 169     ASSERT(Expression->Length);
 170     ASSERT(!FsRtlDoesDbcsContainWildCards(Name));
 171
 172     while (NamePosition < Name->Length && ExpressionPosition < Expression->Length)
 173     {
 174         /* Basic check to test if chars are equal */
 175         if ((Expression->Buffer[ExpressionPosition] == Name->Buffer[NamePosition]))
 176         {
 177             NamePosition++;
 178             ExpressionPosition++;
 179         }
 180         /* Check cases that eat one char */
 181         else if ((Expression->Buffer[ExpressionPosition] == '?') || (Expression->Buffer[ExpressionPosition] == ANSI_DOS_QM) ||
 182                  (Expression->Buffer[ExpressionPosition] == ANSI_DOS_DOT && Name->Buffer[NamePosition] == '.'))
 183         {
 184             NamePosition++;
 185             ExpressionPosition++;
 186         }
 187         /* Test star */
 188         else if (Expression->Buffer[ExpressionPosition] == '*')
 189         {
 190             /* Skip contigous stars */
 191             while (ExpressionPosition + 1 < Expression->Length && Expression->Buffer[ExpressionPosition + 1] == '*')
 192             {
 193                 ExpressionPosition++;
 194             }
 195
 196             /* Save star position */
 197             if (!BackTracking)
 198             {
 199                 BackTracking = ExAllocatePoolWithTag(PagedPool | POOL_RAISE_IF_ALLOCATION_FAILURE,
 200                                                      Expression->Length * sizeof(USHORT), 'nrSF');
 201             }
 202             BackTracking[++StarFound] = ExpressionPosition++;
 203
 204             /* If star is at the end, then eat all rest and leave */
 205             if (ExpressionPosition == Expression->Length)
 206             {
 207                 NamePosition = Name->Length;
 208                 break;
 209             }
 210             else if (Expression->Buffer[ExpressionPosition] != '?')
 211             {
 212                 NamePosition++;
 213             }
 214         }
 215         /* Check DOS_STAR */
 216         else if (Expression->Buffer[ExpressionPosition] == ANSI_DOS_STAR)
 217         {
 218             MatchingChars = NamePosition;
 219             while (MatchingChars < Name->Length)
 220             {
 221                 if (Name->Buffer[MatchingChars] == '.')
 222                 {
 223                     NamePosition = MatchingChars + 1;
 224                 }
 225                 MatchingChars++;
 226             }
 227             ExpressionPosition++;
 228         }
 229         /* If nothing match, try to backtrack */
 230         else if (StarFound >= 0)
 231         {
 232             ExpressionPosition = BackTracking[StarFound--];
 233         }
 234         /* Otherwise, fail */
 235         else
 236         {
 237             break;
 238         }
 239
 240         /* Under certain circumstances, expression is over, but name isn't
 241          * and we can backtrack, then, backtrack */
 242         if (ExpressionPosition == Expression->Length &&
 243             NamePosition != Name->Length && StarFound >= 0)
 244         {
 245             ExpressionPosition = BackTracking[StarFound--];
 246         }
 247     }
 248     if (ExpressionPosition + 1 == Expression->Length && NamePosition == Name->Length &&
 249         Expression->Buffer[ExpressionPosition] == ANSI_DOS_DOT)
 250     {
 251         ExpressionPosition++;
 252     }
 253
 254     if (BackTracking)
 255     {
 256         ExFreePoolWithTag(BackTracking, 'nrSF');
 257     }
 258
 259     return (ExpressionPosition == Expression->Length && NamePosition == Name->Length);
 260 }
 261
 262 /*++
 263  * @name FsRtlIsFatDbcsLegal
 264  * @implemented
 265  *
 266  * Returns TRUE if the given DbcsName is a valid FAT filename (in 8.3)
 267  *
 268  * @param DbcsName
 269  *        The filename to check. It can also contains pathname.
 270  *
 271  * @param WildCardsPermissible
 272  *        If this is set to FALSE and if filename contains wildcard, the function
 273  *        will fail
 274  *
 275  * @param PathNamePermissible
 276  *        If this is set to FALSE and if the filename comes with a pathname, the
 277  *        function will fail
 278  *
 279  * @param LeadingBackslashPermissible
 280  *        If this is set to FALSE and if the filename starts with a backslash, the
 281  *        function will fail
 282  *
 283  * @return TRUE if the DbcsName is legal, FALSE otherwise
 284  *
 285  * @remarks None
 286  *
 287  *--*/
 288 BOOLEAN
 289 NTAPI
 290 FsRtlIsFatDbcsLegal(IN ANSI_STRING DbcsName,
 291                     IN BOOLEAN WildCardsPermissible,
 292                     IN BOOLEAN PathNamePermissible,
 293                     IN BOOLEAN LeadingBackslashPermissible)
 294 {
 295     ANSI_STRING FirstPart, RemainingPart, Name;
 296     BOOLEAN LastDot;
 297     USHORT i;
 298     PAGED_CODE();
 299
 300     /* Just quit if the string is empty */
 301     if (!DbcsName.Length)
 302         return FALSE;
 303
 304     /* DbcsName wasn't supposed to be started with \ */
 305     if (!LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 306         return FALSE;
 307     /* DbcsName was allowed to be started with \, but now, remove it */
 308     else if (LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 309     {
 310         DbcsName.Buffer = DbcsName.Buffer + 1;
 311         DbcsName.Length = DbcsName.Length - 1;
 312         DbcsName.MaximumLength = DbcsName.MaximumLength - 1;
 313     }
 314
 315     /* Extract first part of the DbcsName to work on */
 316     FsRtlDissectDbcs(DbcsName, &FirstPart, &RemainingPart);
 317     while (FirstPart.Length > 0)
 318     {
 319         /* Reset dots count */
 320         LastDot = FALSE;
 321
 322         /* Accept special filename if wildcards are allowed */
 323         if (WildCardsPermissible && (FirstPart.Length == 1 || FirstPart.Length == 2) && FirstPart.Buffer[0] == '.')
 324         {
 325             if (FirstPart.Length == 2)
 326             {
 327                 if (FirstPart.Buffer[1] == '.')
 328                 {
 329                     goto EndLoop;
 330                 }
 331             }
 332             else
 333             {
 334                 goto EndLoop;
 335             }
 336         }
 337
 338         /* Filename must be 8.3 filename */
 339         if (FirstPart.Length < 3 || FirstPart.Length > 12)
 340             return FALSE;
 341
 342         /* Now, we will parse the filename to find everything bad in */
 343         for (i = 0; i < FirstPart.Length; i++)
 344         {
 345             /* First make sure the character it's not the Lead DBCS */
 346             if (FsRtlIsLeadDbcsCharacter(FirstPart.Buffer[i]))
 347             {
 348                 if (i == (FirstPart.Length) - 1)
 349                     return FALSE;
 350                 i++;
 351             }
 352             /* Then check for bad characters */
 353             else if (!FsRtlIsAnsiCharacterLegalFat(FirstPart.Buffer[i], WildCardsPermissible))
 354             {
 355                 return FALSE;
 356             }
 357             else if (FirstPart.Buffer[i] == '.')
 358             {
 359                 /* Filename can only contain one dot */
 360                 if (LastDot)
 361                     return FALSE;
 362
 363                 LastDot = TRUE;
 364
 365                 /* We mustn't have spaces before dot or at the end of the filename
 366                  * and no dot at the beginning of the filename */
 367                 if ((i == (FirstPart.Length) - 1) || i == 0)
 368                     return FALSE;
 369
 370                 if (i > 0)
 371                     if (FirstPart.Buffer[i - 1] == ' ')
 372                         return FALSE;
 373
 374                 /* Filename must be 8.3 filename and not 3.8 filename */
 375                 if ((FirstPart.Length - 1) - i > 3)
 376                     return FALSE;
 377             }
 378         }
 379
 380         /* Filename mustn't finish with a space */
 381         if (FirstPart.Buffer[FirstPart.Length - 1] == ' ')
 382             return FALSE;
 383
 384         EndLoop:
 385         /* Preparing next loop */
 386         Name.Buffer = RemainingPart.Buffer;
 387         Name.Length = RemainingPart.Length;
 388         Name.MaximumLength = RemainingPart.MaximumLength;
 389
 390         /* Call once again our dissect function */
 391         FsRtlDissectDbcs(Name, &FirstPart, &RemainingPart);
 392
 393         /* We found a pathname, it wasn't allowed */
 394         if (FirstPart.Length > 0 && !PathNamePermissible)
 395             return FALSE;
 396     }
 397     return TRUE;
 398 }
 399
 400 /*++
 401  * @name FsRtlIsHpfsDbcsLegal
 402  * @implemented
 403  *
 404  * Returns TRUE if the given DbcsName is a valid HPFS filename
 405  *
 406  * @param DbcsName
 407  *        The filename to check. It can also contains pathname.
 408  *
 409  * @param WildCardsPermissible
 410  *        If this is set to FALSE and if filename contains wildcard, the function
 411  *        will fail
 412  *
 413  * @param PathNamePermissible
 414  *        If this is set to FALSE and if the filename comes with a pathname, the
 415  *        function will fail
 416  *
 417  * @param LeadingBackslashPermissible
 418  *        If this is set to FALSE and if the filename starts with a backslash, the
 419  *        function will fail
 420  *
 421  * @return TRUE if the DbcsName is legal, FALSE otherwise
 422  *
 423  * @remarks None
 424  *
 425  *--*/
 426 BOOLEAN
 427 NTAPI
 428 FsRtlIsHpfsDbcsLegal(IN ANSI_STRING DbcsName,
 429                      IN BOOLEAN WildCardsPermissible,
 430                      IN BOOLEAN PathNamePermissible,
 431                      IN BOOLEAN LeadingBackslashPermissible)
 432 {
 433     ANSI_STRING FirstPart, RemainingPart, Name;
 434     USHORT i;
 435     PAGED_CODE();
 436
 437     /* Just quit if the string is empty */
 438     if (!DbcsName.Length)
 439         return FALSE;
 440
 441     /* DbcsName wasn't supposed to be started with \ */
 442     if (!LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 443         return FALSE;
 444     /* DbcsName was allowed to be started with \, but now, remove it */
 445     else if (LeadingBackslashPermissible && DbcsName.Buffer[0] == '\\')
 446     {
 447         DbcsName.Buffer = DbcsName.Buffer + 1;
 448         DbcsName.Length = DbcsName.Length - 1;
 449         DbcsName.MaximumLength = DbcsName.MaximumLength - 1;
 450     }
 451
 452     /* Extract first part of the DbcsName to work on */
 453     FsRtlDissectDbcs(DbcsName, &FirstPart, &RemainingPart);
 454     while (FirstPart.Length > 0)
 455     {
 456         /* Accept special filename if wildcards are allowed */
 457         if (WildCardsPermissible && (FirstPart.Length == 1 || FirstPart.Length == 2) && FirstPart.Buffer[0] == '.')
 458         {
 459             if (FirstPart.Length == 2)
 460             {
 461                 if (FirstPart.Buffer[1] == '.')
 462                 {
 463                     goto EndLoop;
 464                 }
 465             }
 466             else
 467             {
 468                 goto EndLoop;
 469             }
 470         }
 471
 472         /* Filename must be 255 bytes maximum */
 473         if (FirstPart.Length > 255)
 474             return FALSE;
 475
 476         /* Now, we will parse the filename to find everything bad in */
 477         for (i = 0; i < FirstPart.Length; i++)
 478         {
 479             /* First make sure the character it's not the Lead DBCS */
 480             if (FsRtlIsLeadDbcsCharacter(FirstPart.Buffer[i]))
 481             {
 482                 if (i == (FirstPart.Length) - 1)
 483                     return FALSE;
 484                 i++;
 485             }
 486             /* Then check for bad characters */
 487             else if (!FsRtlIsAnsiCharacterLegalHpfs(FirstPart.Buffer[i], WildCardsPermissible))
 488             {
 489                 return FALSE;
 490             }
 491         }
 492
 493         /* Filename mustn't finish with a space or a dot */
 494         if ((FirstPart.Buffer[FirstPart.Length - 1] == ' ') ||
 495             (FirstPart.Buffer[FirstPart.Length - 1] == '.'))
 496             return FALSE;
 497
 498         EndLoop:
 499         /* Preparing next loop */
 500         Name.Buffer = RemainingPart.Buffer;
 501         Name.Length = RemainingPart.Length;
 502         Name.MaximumLength = RemainingPart.MaximumLength;
 503
 504         /* Call once again our dissect function */
 505         FsRtlDissectDbcs(Name, &FirstPart, &RemainingPart);
 506
 507         /* We found a pathname, it wasn't allowed */
 508         if (FirstPart.Length > 0 && !PathNamePermissible)
 509             return FALSE;
 510     }
 511     return TRUE;
 512 }