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