MdePkg/Library/BaseLib/FilePaths.c

   1 /** @file
   2   Defines file-path manipulation functions.
   3
   4   Copyright (c) 2011 - 2016, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12 **/
  13 #include  <Uefi/UefiBaseType.h>
  14 #include  <Library/BaseMemoryLib.h>
  15 #include  <Library/BaseLib.h>
  16 #include  <Protocol/SimpleTextIn.h>
  17
  18 /**
  19   Removes the last directory or file entry in a path by changing the last
  20   L'\' to a CHAR_NULL. For a path which is like L"fs0:startup.nsh",
  21   it's converted to L"fs0:".
  22
  23   @param[in,out] Path     A pointer to the path to modify.
  24
  25   @retval FALSE     Nothing was found to remove.
  26   @retval TRUE      A directory or file was removed.
  27 **/
  28 BOOLEAN
  29 EFIAPI
  30 PathRemoveLastItem(
  31   IN OUT CHAR16 *Path
  32   )
  33 {
  34   CHAR16        *Walker;
  35   CHAR16        *LastSlash;
  36   //
  37   // get directory name from path... ('chop' off extra)
  38   //
  39   for ( Walker = Path, LastSlash = NULL
  40       ; Walker != NULL && *Walker != CHAR_NULL
  41       ; Walker++
  42      ){
  43     if ((*Walker == L'\\' || *Walker == L':') && *(Walker + 1) != CHAR_NULL) {
  44       LastSlash = Walker+1;
  45     }
  46   }
  47   if (LastSlash != NULL) {
  48     *LastSlash = CHAR_NULL;
  49     return (TRUE);
  50   }
  51   return (FALSE);
  52 }
  53
  54 /**
  55   Function to clean up paths.
  56
  57   - Single periods in the path are removed.
  58   - Double periods in the path are removed along with a single parent directory.
  59   - Forward slashes L'/' are converted to backward slashes L'\'.
  60
  61   This will be done inline and the existing buffer may be larger than required
  62   upon completion.
  63
  64   @param[in] Path       The pointer to the string containing the path.
  65
  66   @return       Returns Path, otherwise returns NULL to indicate that an error has occured.
  67 **/
  68 CHAR16*
  69 EFIAPI
  70 PathCleanUpDirectories(
  71   IN CHAR16 *Path
  72   )
  73 {
  74   CHAR16  *TempString;
  75   UINTN   TempSize;
  76
  77   if (Path==NULL) {
  78     return(NULL);
  79   }
  80   //
  81   // Fix up the '/' vs '\'
  82   //
  83   for (TempString = Path ; TempString != NULL && *TempString != CHAR_NULL ; TempString++) {
  84     if (*TempString == L'/') {
  85       *TempString = L'\\';
  86     }
  87   }
  88   //
  89   // Fix up the ..
  90   //
  91   while ((TempString = StrStr(Path, L"\\..\\")) != NULL) {
  92     *TempString = CHAR_NULL;
  93     TempString  += 4;
  94     PathRemoveLastItem(Path);
  95     TempSize = StrSize(TempString);
  96     CopyMem(Path+StrLen(Path), TempString, TempSize);
  97   }
  98   if ((TempString = StrStr(Path, L"\\..")) != NULL && *(TempString + 3) == CHAR_NULL) {
  99     *TempString = CHAR_NULL;
 100     if (!PathRemoveLastItem(Path)) {
 101       *TempString = L'\\';
 102     }
 103   }
 104   //
 105   // Fix up the .
 106   //
 107   while ((TempString = StrStr(Path, L"\\.\\")) != NULL) {
 108     *TempString = CHAR_NULL;
 109     TempString  += 2;
 110     TempSize = StrSize(TempString);
 111     CopyMem(Path+StrLen(Path), TempString, TempSize);
 112   }
 113   if ((TempString = StrStr(Path, L"\\.")) != NULL && *(TempString + 2) == CHAR_NULL) {
 114     *(TempString + 1) = CHAR_NULL;
 115   }
 116
 117   while ((TempString = StrStr(Path, L"\\\\")) != NULL) {
 118     *TempString = CHAR_NULL;
 119     TempString  += 1;
 120     TempSize = StrSize(TempString);
 121     CopyMem(Path+StrLen(Path), TempString, TempSize);
 122   }
 123   if ((TempString = StrStr(Path, L"\\\\")) != NULL && *(TempString + 1) == CHAR_NULL) {
 124     *(TempString) = CHAR_NULL;
 125   }
 126
 127   return (Path);
 128 }
 129