判断dll / exe是否为托管(managed / unmanaged)

由于软件下发、部署的考虑，我们可能会对托管/非托管的dll采用不同的更新策略。

1、.NET方式
通过Assembly类的LoadFrom 、LoadFile均可， 异常为BadImageFormatException ，则基本可以判断是非托管dll/exe
(也存在硬修改为.dll或.exe的可能)

2、COM方式
http://www.codeguru.com/cpp/w-p/dll/openfaq/article.php/c14001/

BOOL IsManaged(LPTSTR lpszImageName)
{
   BOOL bIsManaged = FALSE;    //variable that indicates whether
                               //managed or not.
   TCHAR szPath[MAX_PATH];     //for convenience

   HANDLE hFile = CreateFile(lpszImageName, GENERIC_READ,
                             FILE_SHARE_READ,NULL,OPEN_EXISTING,
                             FILE_ATTRIBUTE_NORMAL,NULL);

   //attempt the standard paths (Windows dir and system dir) if
   //CreateFile failed in the first place.
   if(INVALID_HANDLE_VALUE == hFile)
   {
      //try to locate in Windows directory
      GetWindowsDirectory(szPath,MAX_PATH);
      _tcscat(szPath,_T("\\"));
      _tcscat(szPath,lpszImageName);
      hFile = CreateFile(szPath, GENERIC_READ, FILE_SHARE_READ,
                         NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,
                         NULL);
   }

   if(INVALID_HANDLE_VALUE == hFile)
   {
      //try to locate in system directory
      GetSystemDirectory(szPath,MAX_PATH);
      _tcscat(szPath,_T("\\"));
      _tcscat(szPath,lpszImageName);
      hFile = CreateFile(szPath, GENERIC_READ, FILE_SHARE_READ,
                         NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,
                         NULL);
   }

   if(INVALID_HANDLE_VALUE != hFile)
   {
      //succeeded
      HANDLE hOpenFileMapping = CreateFileMapping(hFile,NULL,
                                                  PAGE_READONLY,0,
                                                  0,NULL);
      if(hOpenFileMapping)
      {
         BYTE* lpBaseAddress = NULL;

         //Map the file, so it can be simply be acted on as a
         //contiguous array of bytes
         lpBaseAddress = (BYTE*)MapViewOfFile(hOpenFileMapping,
                                              FILE_MAP_READ,0,0,0);

         if(lpBaseAddress)
         {
            //having mapped the executable, now start navigating
            //through the sections

            //DOS header is straightforward. It is the topmost
            //structure in the PE file
            //i.e. the one at the lowest offset into the file
            IMAGE_DOS_HEADER* pDOSHeader =
               (IMAGE_DOS_HEADER*)lpBaseAddress;

            //the only important data in the DOS header is the
            //e_lfanew
            //the e_lfanew points to the offset of the beginning
            //of NT Headers data
            IMAGE_NT_HEADERS* pNTHeaders =
               (IMAGE_NT_HEADERS*)((BYTE*)pDOSHeader +
               pDOSHeader->e_lfanew);

            //store the section header for future use. This will
            //later be need to check to see if metadata lies within
            //the area as indicated by the section headers
            IMAGE_SECTION_HEADER* pSectionHeader =
               (IMAGE_SECTION_HEADER*)((BYTE*)pNTHeaders +
               sizeof(IMAGE_NT_HEADERS));

            //Now, start parsing
            //First of all check if it is a PE file. All assemblies
            //are PE files.
            if(pNTHeaders->Signature == IMAGE_NT_SIGNATURE)
            {
               //start parsing COM table (this is what points to
               //the metadata and other information)
               DWORD dwNETHeaderTableLocation =
                  pNTHeaders->OptionalHeader.DataDirectory
                  [IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR].
                  VirtualAddress;

               if(dwNETHeaderTableLocation)
               {
                  //.NET header data does exist for this module;
                  //find its location in one of the sections
                  IMAGE_COR20_HEADER* pNETHeader =
                     (IMAGE_COR20_HEADER*)((BYTE*)pDOSHeader +
                     GetActualAddressFromRVA(pSectionHeader,
                     pNTHeaders,dwNETHeaderTableLocation));

                  if(pNETHeader)
                  {
                     //valid address obtained. Suffice it to say,
                     //this is good enough to identify this as a
                     //valid managed component
                     bIsManaged = TRUE;
                  }
               }
            }
            else
            {
               cout << "Not PE file\r\n";
            }
            //cleanup
            UnmapViewOfFile(lpBaseAddress);
         }
         //cleanup
         CloseHandle(hOpenFileMapping);
      }
      //cleanup
      CloseHandle(hFile);
   }
   return bIsManaged;
}