Writing Windows WDM Device Drivers

 // Get buffer size
 printf('
Test %d
',TestNo++);
 char* Buffer = new char[BufferSize+1];
 if (!DeviceIoControl(hWdm1, IOCTL_WDM1_GET_BUFFER,
  NULL, 0,// Input
  Buffer, BufferSize,// Output
  &BytesReturned, NULL)) printf('XXX Could not get buffer
');
 else printf(' First DWORD of buffer is %08X (%d bytes returned)
',*((DWORD*)Buffer),Bytes Returned);
 ///////////////////////////////////////////////////////////////////////
 // Get too big a buffer size
 printf('
Test %d
',TestNo++);
 if (!DeviceIoControl(hWdm1, IOCTL_WDM1_GET_BUFFER,
  NULL, 0,// Input
  Buffer, BufferSize+1,// Output
  &BytesReturned, NULL)) printf(' Too big get buffer failed correctly %d
',GetLastError());
 else printf('XXX Too big get buffer unexpectedly succeeded
');
 ///////////////////////////////////////////////////////////////////////
 // Zero all buffer bytes
 printf('
Test %d
',TestNo++);
 if (!DeviceIoControl(hWdm1, IOCTL_WDM1_ZERO_BUFFER,
  NULL, 0,// Input
  NULL, 0,// Output
  &BytesReturned, NULL)) printf('XXX Zero buffer failed %d
' ,GetLastError());
 else printf(' Zero buffer succeeded
');
 if (!DeviceIoControl(hWdm1, IOCTL_WDM1_GET_BUFFER,
  NULL, 0,// Input
  Buffer, BufferSize,// Output
  &BytesReturned, NULL)) printf('XXX Could not get buffer
');
 else printf(' First DWORD of buffer is %08X (%d bytes returned) n',*((DWORD*)Buffer),BytesReturned);
 ///////////////////////////////////////////////////////////////////////
 // Remove buffer
 printf('
Test %d
',TestNo++);
 if (!DeviceIoControl(hWdm1, IOCTL_WDM1_REMOVE_BUFFER,
  NULL, 0,// Input
  NULL, 0,// Output
  &BytesReturned, NULL)) printf('XXX Remove buffer failed %d
',GetLastError());
 else printf(' Remove buffer succeeded
');
 if (!DeviceloControl(hWdm1, IOCTL_WDM1_GET_BUFFER_SIZE,
  NULL, 0,// Input
  &BufferSize, sizeof(ULONG),// Output
  &BytesReturned, NULL)) printf('XXX Could not get buffer size
');
 else printf(' Buffer size is %i (%d bytes returned)
',BufferSize,BytesReturned);
 ///////////////////////////////////////////////////////////////////////
 // Unrecognised IOCTL
 printf('
Test %d
',TestNo++);
 if (!DeviceIoControl(hWdm1, IOCTL_WDM1_UNRECOGNISED,
  NULL, 0,// Input
  NULL, 0,1/ Output
  &BytesReturned, NULL)) printf(' Unrecognised IOCTL correctly failed %d
',GetLastError());
 else printf('XXX Unrecognised IOCTL unexpectedly succeeded
');
 ///////////////////////////////////////////////////////////////////////
 // Write 0xabcdef01 to start of buffer
 printf('
Test %d
',TestNo++);
 dwNewPtr = SetFilePointer(hWdm1, 0, NULL, FILE_BEGIN);
 if (dwNewPtr==0xFFFFFFFF) printf('XXX SetFilePointer failed %d
',GetLastError());
 else printf(' SetFilePointer worked
');
 Wvalue = 0xabcdef01;
 if (!WriteFile(hWdm1, &Wvalue, 4, &TxdBytes, NULL)) printf('XXX Could not write %X
', Wvalue);
 else if( TxdBytes==4) printf(' Write 0xabcdef01 succeeded
');
 else printf('XXX Wrong number of bytes written: %d
',TxdBytes);
 /////////////////////////////////////////////////////////////////////////
 // Close device
 printf('
Test %d
',TestNo++);
 if (!CloseHandle(hWdm1)) printf('XXX CloseHandle failed %d
', GetLastError());
 else printf(' CloseHandle worked
');
 /////////////////////////////////////////////////////////////////////////
 delete Buffer;
 printf('
Press enter please');
 char line[80];
 gets(line);
 return 0;
}
//////////////////////////////////////////////////////////////////////////
//GetDeviceViaInterface:Open a handle via a device interface
HANDLE GetDeviceViaInterface(GUID* pGuid, DWORD instance) {
 // Get handle to relevant device information set
 HDEVINFO info = SetupDiGetClassDevs(pGuid, NULL, NULL, DIGCF_PRESENT | DIGCF_INTERFACEDEVICE);
 if (info==INVALID_HANDLE_VALUE) {
  printf('No HDEVINFO available for this GUID
');
  return NULL;
 }
 // Get interface data for the requested instance
 SP_INTERFACE_DEVICE_DATA ifdata;
 ifdata.cbSize = sizeof(ifdata);
 if (!SetupDiEnumDeviceInterfaces(info, NULL, pGuid, instance, &ifdata)) {
  printf('No SP_INTERFACE_DEVICE_DATA available for this GUID instance
');
  SetupDiDestroyDeviceInfoList(info);
  return NULL;
 }