reactos/lib/drivers/ntoskrnl_vista/fsrtl.c

   1 /*
   2  * PROJECT:         ReactOS Kernel - Vista+ APIs
   3  * LICENSE:         GPL v2 - See COPYING in the top level directory
   4  * FILE:            lib/drivers/ntoskrnl_vista/fsrtl.c
   5  * PURPOSE:         FsRtl functions of Vista+
   6  * PROGRAMMERS:     Pierre Schweitzer <pierre@reactos.org>
   7  */
   8
   9 #include <ntdef.h>
  10 #include <ntifs.h>
  11
  12 NTKERNELAPI
  13 NTSTATUS
  14 NTAPI
  15 FsRtlRemoveDotsFromPath(IN PWSTR OriginalString,
  16                         IN USHORT PathLength,
  17                         OUT USHORT *NewLength)
  18 {
  19     USHORT Length, ReadPos, WritePos = 0;
  20
  21     Length = PathLength / sizeof(WCHAR);
  22
  23     if (Length == 3 && OriginalString[0] == '\\' && OriginalString[1] == '.' && OriginalString[2] == '.')
  24     {
  25         return STATUS_IO_REPARSE_DATA_INVALID;
  26     }
  27
  28     if (Length == 2 && OriginalString[0] == '.' && OriginalString[1] == '.')
  29     {
  30         return STATUS_IO_REPARSE_DATA_INVALID;
  31     }
  32
  33     if (Length > 2 && OriginalString[0] == '.' && OriginalString[1] == '.' && OriginalString[2] == '\\')
  34     {
  35         return STATUS_IO_REPARSE_DATA_INVALID;
  36     }
  37
  38     if (Length > 0)
  39     {
  40         ReadPos = 0;
  41
  42         for (; ReadPos < Length; ++WritePos)
  43         {
  44             for (; ReadPos < Length; ++ReadPos)
  45             {
  46                 if (ReadPos < Length - 1 && OriginalString[ReadPos] == '\\' && OriginalString[ReadPos + 1] == '\\')
  47                 {
  48                     continue;
  49                 }
  50
  51                 if (OriginalString[ReadPos] != '.')
  52                 {
  53                     break;
  54                 }
  55
  56                 if (ReadPos == Length - 1)
  57                 {
  58                     if (OriginalString[ReadPos - 1] == '\\')
  59                     {
  60                         if (WritePos > 1)
  61                         {
  62                             --WritePos;
  63                         }
  64
  65                         continue;
  66                     }
  67
  68                     OriginalString[WritePos] = '.';
  69                     ++WritePos;
  70                     continue;
  71                 }
  72
  73                 if (OriginalString[ReadPos + 1] == '\\')
  74                 {
  75                     if (OriginalString[ReadPos - 1] != '\\')
  76                     {
  77                         OriginalString[WritePos] = '.';
  78                         ++WritePos;
  79                         continue;
  80                     }
  81                 }
  82                 else
  83                 {
  84                     if (OriginalString[ReadPos + 1] != '.' || OriginalString[ReadPos - 1] != '\\' ||
  85                         ((ReadPos != Length - 2) && OriginalString[ReadPos + 2] != '\\'))
  86                     {
  87                         OriginalString[WritePos] = '.';
  88                         ++WritePos;
  89                         continue;
  90                     }
  91
  92                     for (WritePos -= 2; (SHORT)WritePos > 0 && OriginalString[WritePos] != '\\'; --WritePos);
  93
  94                     if ((SHORT)WritePos < 0 || OriginalString[WritePos] != '\\')
  95                     {
  96                         return STATUS_IO_REPARSE_DATA_INVALID;
  97                     }
  98
  99                     if (WritePos == 0 && ReadPos == Length - 2)
 100                     {
 101                         WritePos = 1;
 102                     }
 103                 }
 104
 105                 ++ReadPos;
 106             }
 107
 108             OriginalString[WritePos] = OriginalString[ReadPos];
 109             ++ReadPos;
 110         }
 111     }
 112
 113     *NewLength = WritePos * sizeof(WCHAR);
 114
 115     while (WritePos < Length)
 116     {
 117         OriginalString[WritePos++] = UNICODE_NULL;
 118     }
 119
 120     return STATUS_SUCCESS;
 121 }