void create_pipe()

in demo_example/asio/asio/impl/connect_pipe.ipp [45:129]

• 74 lines of code
• 11 McCabe index (conditional complexity)

void create_pipe(native_pipe_handle p[2], asio::error_code& ec)
{
#if defined(ASIO_HAS_IOCP)
  using namespace std; // For sprintf and memcmp.

  static long counter1 = 0;
  static long counter2 = 0;

  long n1 = ::InterlockedIncrement(&counter1);
  long n2 = (static_cast<unsigned long>(n1) % 0x10000000) == 0
    ? ::InterlockedIncrement(&counter2)
    : ::InterlockedExchangeAdd(&counter2, 0);

  wchar_t pipe_name[128];
#if defined(ASIO_HAS_SECURE_RTL)
  swprintf_s(
#else // defined(ASIO_HAS_SECURE_RTL)
  _snwprintf(
#endif // defined(ASIO_HAS_SECURE_RTL)
      pipe_name, 128,
      L"\\\\.\\pipe\\asio-A0812896-741A-484D-AF23-BE51BF620E22-%u-%ld-%ld",
      static_cast<unsigned int>(::GetCurrentProcessId()), n1, n2);

  p[0] = ::CreateNamedPipeW(pipe_name,
      PIPE_ACCESS_INBOUND | FILE_FLAG_OVERLAPPED,
      0, 1, 8192, 8192, 0, 0);

  if (p[0] == INVALID_HANDLE_VALUE)
  {
    DWORD last_error = ::GetLastError();
    ec.assign(last_error, asio::error::get_system_category());
    return;
  }

  p[1] = ::CreateFileW(pipe_name, GENERIC_WRITE, 0,
    0, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0);

  if (p[1] == INVALID_HANDLE_VALUE)
  {
    DWORD last_error = ::GetLastError();
    ::CloseHandle(p[0]);
    ec.assign(last_error, asio::error::get_system_category());
    return;
  }

# if _WIN32_WINNT >= 0x601
  unsigned char nonce[16];
  if (::BCryptGenRandom(0, nonce, sizeof(nonce),
        BCRYPT_USE_SYSTEM_PREFERRED_RNG) != 0)
  {
    ec = asio::error::connection_aborted;
    ::CloseHandle(p[0]);
    ::CloseHandle(p[1]);
    return;
  }

  DWORD bytes_written = 0;
  BOOL ok = ::WriteFile(p[1], nonce, sizeof(nonce), &bytes_written, 0);
  if (!ok || bytes_written != sizeof(nonce))
  {
    ec = asio::error::connection_aborted;
    ::CloseHandle(p[0]);
    ::CloseHandle(p[1]);
    return;
  }

  unsigned char nonce_check[sizeof(nonce)];
  DWORD bytes_read = 0;
  ok = ::ReadFile(p[0], nonce_check, sizeof(nonce), &bytes_read, 0);
  if (!ok || bytes_read != sizeof(nonce)
      || memcmp(nonce, nonce_check, sizeof(nonce)) != 0)
  {
    ec = asio::error::connection_aborted;
    ::CloseHandle(p[0]);
    ::CloseHandle(p[1]);
    return;
  }
#endif // _WIN32_WINNT >= 0x601

  ec.assign(0, ec.category());
#else // defined(ASIO_HAS_IOCP)
  int result = ::pipe(p);
  detail::descriptor_ops::get_last_error(ec, result != 0);
#endif // defined(ASIO_HAS_IOCP)
}