How to get the Directory name/path from an opened handle.

Question

On opening a directory via zwopenfile(open directory option), it returns a handle for the directory path. Now I need to get the directory path from the handle. Its my requirement.

I could see an example(please see the code below) where file name can be fetched from file handle. But the below example does not help for directory. Is there any possibilities in fetching directory name from its opened handle.

 CHAR* GetFileNameFromHandle(HANDLE hFile) 
{
  BOOL bSuccess = FALSE;
  TCHAR pszFilename[MAX_PATH+1];
  HANDLE hFileMap;

  // Get the file size.
  DWORD dwFileSizeHi = 0;
  DWORD dwFileSizeLo = GetFileSize(hFile, &dwFileSizeHi); 

  if( dwFileSizeLo == 0 && dwFileSizeHi == 0 )
  {
     printf("Cannot map a file with a length of zero.\n");
     return FALSE;
  }

  // Create a file mapping object.
  hFileMap = CreateFileMappingW(hFile, 
                    NULL, 
                    PAGE_READONLY,
                    0, 
                    1,
                    NULL);

  if (hFileMap) 
  {
    // Create a file mapping to get the file name.
    void* pMem = MapViewOfFile(hFileMap, FILE_MAP_READ, 0, 0, 1);

    if (pMem) 
    {
      if (GetMappedFileNameW (GetCurrentProcess(), 
                             pMem, 
                             pszFilename,
                             MAX_PATH)) 
      {

        // Translate path with device name to drive letters.
        TCHAR szTemp[1024];
        szTemp[0] = '\0';

        if (GetLogicalDriveStrings(1024-1, szTemp)) 
        {
          TCHAR szName[MAX_PATH];
          TCHAR szDrive[3] = TEXT(" :");
          BOOL bFound = FALSE;
          TCHAR* p = szTemp;

          do 
          {
            // Copy the drive letter to the template string
            *szDrive = *p;

            // Look up each device name
            if (QueryDosDevice(szDrive, szName, MAX_PATH))
            {
              UINT uNameLen = _tcslen(szName);

              if (uNameLen < MAX_PATH) 
              {
                bFound = _tcsnicmp(pszFilename, szName, uNameLen) == 0;

                if (bFound && *(pszFilename + uNameLen) == _T('\\')) 
                {
                  // Reconstruct pszFilename using szTempFile
                  // Replace device path with DOS path
                  TCHAR szTempFile[MAX_PATH];
                  StringCchPrintf(szTempFile,
                            MAX_PATH,
                            TEXT("%s%s"),
                            szDrive,
                            pszFilename+uNameLen);
                  StringCchCopyN(pszFilename, MAX_PATH+1, szTempFile, _tcslen(szTempFile));
                }
              }
            }

            // Go to the next NULL character.
            while (*p++);
          } while (!bFound && *p); // end of string
        }
      }
      bSuccess = TRUE;
      UnmapViewOfFile(pMem);
    } 

    CloseHandle(hFileMap);
  }
  _tprintf(TEXT("File name is %s\n"), pszFilename);
  return( pszFilename);
}

Answer 1

The example from MSDN, which you posted, gives a 'fully qualified' file name, i.e. with the drive letter and the full path.

With that, it should be easy to get the directory name: just strip off everything after the last \.

Answer 2

NtQueryObject did it.