通过注册表的句柄得到当前句柄在注册表中的路径

#include <windows.h>
#include <string>

typedef LONG NTSTATUS;

#ifndef STATUS_SUCCESS
#define STATUS_SUCCESS ((NTSTATUS)0x00000000L)
#endif

#ifndef STATUS_BUFFER_TOO_SMALL
#define STATUS_BUFFER_TOO_SMALL ((NTSTATUS)0xC0000023L)
#endif

std::wstring GetKeyPathFromKKEY(HKEY key)
{
    std::wstring keyPath;
    if (key != NULL)
    {
     HMODULE dll = LoadLibrary(L"ntdll.dll");
     if (dll != NULL) {
      typedef DWORD (__stdcall *ZwQueryKeyType)(
       HANDLE  KeyHandle,
       int KeyInformationClass,
       PVOID  KeyInformation,
       ULONG  Length,
       PULONG  ResultLength);

      ZwQueryKeyType func = reinterpret_cast<ZwQueryKeyType>(::GetProcAddress(dll, "ZwQueryKey"));

      if (func != NULL) {
       DWORD size = 0;
       DWORD result = 0;
       result = func(key, 3, 0, 0, &size);
       if (result == STATUS_BUFFER_TOO_SMALL)
       {
        size = size + 2;
        wchar_t* buffer = new (std::nothrow) wchar_t[size];
        if (buffer != NULL)
        {
         result = func(key, 3, buffer, size, &size);
         if (result == STATUS_SUCCESS)
         {
          buffer[size / sizeof(wchar_t)] = L'\0';
          keyPath = std::wstring(buffer + 2);
         }

         delete[] buffer;
        }
       }
      }

      FreeLibrary(dll);
     }
    }
    return keyPath;
}

int _tmain(int argc, _TCHAR* argv[])
{
    HKEY key = NULL;
    LONG ret = ERROR_SUCCESS;

    ret = RegOpenKey(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Microsoft", &key);
    if (ret == ERROR_SUCCESS)
    {
     wprintf_s(L"Key path for %p is '%s'.", key, GetKeyPathFromKKEY(key).c_str());
     RegCloseKey(key);
    }

    return 0;
}