Aaru.Server/DiscImageChef.Devices/Windows/Usb.cs

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : Usb.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Windows direct device access.
//
// --[ Description ] ----------------------------------------------------------
//
//     Contains code to access USB device information under Windows.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General internal License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General internal License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2018 Natalia Portillo
// Copyright © 2007 Fort Hood TX, herethen, Public Domain
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.InteropServices;
using System.Text;

namespace DiscImageChef.Devices.Windows
{
    // TODO: Even after cleaning, refactoring and xml-documenting, this code needs some love
    static partial class Usb
    {
        #region "API Region" 
        // ********************** Constants ************************

        const int GENERIC_WRITE = 0x40000000;
        const int FILE_SHARE_READ = 0x1;
        const int FILE_SHARE_WRITE = 0x2;
        const int OPEN_EXISTING = 0x3;
        const int INVALID_HANDLE_VALUE = -1;

        const int IOCTL_GET_HCD_DRIVERKEY_NAME = 0x220424;
        const int IOCTL_USB_GET_ROOT_HUB_NAME = 0x220408;
        const int IOCTL_USB_GET_NODE_INFORMATION = 0x220408; // same as above... strange, eh?
        const int IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX = 0x220448;
        const int IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION = 0x220410;
        const int IOCTL_USB_GET_NODE_CONNECTION_NAME = 0x220414;
        const int IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME = 0x220420;

        const int USB_DEVICE_DESCRIPTOR_TYPE = 0x1;
        const int USB_CONFIGURATION_DESCRIPTOR_TYPE = 0x2;
        const int USB_STRING_DESCRIPTOR_TYPE = 0x3;

        const int BUFFER_SIZE = 2048;
        const int MAXIMUM_USB_STRING_LENGTH = 255;

        const string GUID_DEVINTERFACE_HUBCONTROLLER = "3abf6f2d-71c4-462a-8a92-1e6861e6af27";
        const string REGSTR_KEY_USB = "USB";
        const int DIGCF_PRESENT = 0x2;
        const int DIGCF_ALLCLASSES = 0x4;
        const int DIGCF_DEVICEINTERFACE = 0x10;
        const int SPDRP_DRIVER = 0x9;
        const int SPDRP_DEVICEDESC = 0x0;
        const int REG_SZ = 1;

        // ********************** Enumerations ************************

        //typedef enum _USB_HUB_NODE {
        //    UsbHub,
        //    UsbMIParent
        //} USB_HUB_NODE;
        enum UsbHubNode
        {
            UsbHub,
            UsbMiParent
        }

        //typedef enum _USB_CONNECTION_STATUS {
        //    NoDeviceConnected,
        //    DeviceConnected,
        //    DeviceFailedEnumeration,
        //    DeviceGeneralFailure,
        //    DeviceCausedOvercurrent,
        //    DeviceNotEnoughPower,
        //    DeviceNotEnoughBandwidth,
        //    DeviceHubNestedTooDeeply,
        //    DeviceInLegacyHub
        //} USB_CONNECTION_STATUS, *PUSB_CONNECTION_STATUS;
        enum UsbConnectionStatus
        {
            NoDeviceConnected,
            DeviceConnected,
            DeviceFailedEnumeration,
            DeviceGeneralFailure,
            DeviceCausedOvercurrent,
            DeviceNotEnoughPower,
            DeviceNotEnoughBandwidth,
            DeviceHubNestedTooDeeply,
            DeviceInLegacyHub
        }

        //typedef enum _USB_DEVICE_SPEED {
        //    UsbLowSpeed = 0,
        //    UsbFullSpeed,
        //    UsbHighSpeed
        //} USB_DEVICE_SPEED;
        enum UsbDeviceSpeed : byte
        {
            UsbLowSpeed,
            UsbFullSpeed,
            UsbHighSpeed
        }

        // ********************** Stuctures ************************

        //typedef struct _SP_DEVINFO_DATA {
        //  DWORD cbSize;
        //  GUID ClassGuid;
        //  DWORD DevInst;
        //  ULONG_PTR Reserved;
        //} SP_DEVINFO_DATA,  *PSP_DEVINFO_DATA;
        [StructLayout(LayoutKind.Sequential)]
        struct SpDevinfoData
        {
            internal int cbSize;
            internal Guid ClassGuid;
            internal IntPtr DevInst;
            internal IntPtr Reserved;
        }

        //typedef struct _SP_DEVICE_INTERFACE_DATA {
        //  DWORD cbSize;
        //  GUID InterfaceClassGuid;
        //  DWORD Flags;
        //  ULONG_PTR Reserved;
        //} SP_DEVICE_INTERFACE_DATA,  *PSP_DEVICE_INTERFACE_DATA;
        [StructLayout(LayoutKind.Sequential)]
        struct SpDeviceInterfaceData
        {
            internal int cbSize;
            internal Guid InterfaceClassGuid;
            internal int Flags;
            internal IntPtr Reserved;
        }

        //typedef struct _SP_DEVICE_INTERFACE_DETAIL_DATA {
        //  DWORD cbSize;
        //  TCHAR DevicePath[ANYSIZE_ARRAY];
        //} SP_DEVICE_INTERFACE_DETAIL_DATA,  *PSP_DEVICE_INTERFACE_DETAIL_DATA;
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct SpDeviceInterfaceDetailData
        {
            internal int cbSize;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = BUFFER_SIZE)] internal string DevicePath;
        }

        //typedef struct _USB_HCD_DRIVERKEY_NAME {
        //    ULONG ActualLength;
        //    WCHAR DriverKeyName[1];
        //} USB_HCD_DRIVERKEY_NAME, *PUSB_HCD_DRIVERKEY_NAME;
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct UsbHcdDriverkeyName
        {
            internal int ActualLength;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = BUFFER_SIZE)] internal string DriverKeyName;
        }

        //typedef struct _USB_ROOT_HUB_NAME {
        //    ULONG  ActualLength;
        //    WCHAR  RootHubName[1];
        //} USB_ROOT_HUB_NAME, *PUSB_ROOT_HUB_NAME;
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct UsbRootHubName
        {
            internal int ActualLength;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = BUFFER_SIZE)] internal string RootHubName;
        }

        //typedef struct _USB_HUB_DESCRIPTOR {
        //    UCHAR  bDescriptorLength;
        //    UCHAR  bDescriptorType;
        //    UCHAR  bNumberOfPorts;
        //    USHORT  wHubCharacteristics;
        //    UCHAR  bPowerOnToPowerGood;
        //    UCHAR  bHubControlCurrent;
        //    UCHAR  bRemoveAndPowerMask[64];
        //} USB_HUB_DESCRIPTOR, *PUSB_HUB_DESCRIPTOR;
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct UsbHubDescriptor
        {
            internal byte bDescriptorLength;
            internal byte bDescriptorType;
            internal byte bNumberOfPorts;
            internal short wHubCharacteristics;
            internal byte bPowerOnToPowerGood;
            internal byte bHubControlCurrent;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 64)] internal byte[] bRemoveAndPowerMask;
        }

        //typedef struct _USB_HUB_INFORMATION {
        //    USB_HUB_DESCRIPTOR HubDescriptor;
        //    BOOLEAN HubIsBusPowered;
        //} USB_HUB_INFORMATION, *PUSB_HUB_INFORMATION;
        [StructLayout(LayoutKind.Sequential)]
        struct UsbHubInformation
        {
            internal UsbHubDescriptor HubDescriptor;
            internal byte HubIsBusPowered;
        }

        //typedef struct _USB_NODE_INFORMATION {
        //    USB_HUB_NODE  NodeType;
        //    union {
        //        USB_HUB_INFORMATION  HubInformation;
        //        USB_MI_PARENT_INFORMATION  MiParentInformation;
        //    } u;
        //} USB_NODE_INFORMATION, *PUSB_NODE_INFORMATION;
        [StructLayout(LayoutKind.Sequential)]
        struct UsbNodeInformation
        {
            internal int NodeType;
            internal UsbHubInformation HubInformation; // Yeah, I'm assuming we'll just use the first form
        }

        //typedef struct _USB_NODE_CONNECTION_INFORMATION_EX {
        //    ULONG  ConnectionIndex;
        //    USB_DEVICE_DESCRIPTOR  DeviceDescriptor;
        //    UCHAR  CurrentConfigurationValue;
        //    UCHAR  Speed;
        //    BOOLEAN  DeviceIsHub;
        //    USHORT  DeviceAddress;
        //    ULONG  NumberOfOpenPipes;
        //    USB_CONNECTION_STATUS  ConnectionStatus;
        //    USB_PIPE_INFO  PipeList[0];
        //} USB_NODE_CONNECTION_INFORMATION_EX, *PUSB_NODE_CONNECTION_INFORMATION_EX;
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct UsbNodeConnectionInformationEx
        {
            internal int ConnectionIndex;
            internal UsbDeviceDescriptor DeviceDescriptor;
            internal byte CurrentConfigurationValue;
            internal byte Speed;
            internal byte DeviceIsHub;
            internal short DeviceAddress;
            internal int NumberOfOpenPipes;

            internal int ConnectionStatus;
            //internal IntPtr PipeList;
        }

        //typedef struct _USB_DEVICE_DESCRIPTOR {
        //    UCHAR  bLength;
        //    UCHAR  bDescriptorType;
        //    USHORT  bcdUSB;
        //    UCHAR  bDeviceClass;
        //    UCHAR  bDeviceSubClass;
        //    UCHAR  bDeviceProtocol;
        //    UCHAR  bMaxPacketSize0;
        //    USHORT  idVendor;
        //    USHORT  idProduct;
        //    USHORT  bcdDevice;
        //    UCHAR  iManufacturer;
        //    UCHAR  iProduct;
        //    UCHAR  iSerialNumber;
        //    UCHAR  bNumConfigurations;
        //} USB_DEVICE_DESCRIPTOR, *PUSB_DEVICE_DESCRIPTOR ;
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        [SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
        internal struct UsbDeviceDescriptor
        {
            internal byte bLength;
            internal byte bDescriptorType;
            internal short bcdUSB;
            internal byte bDeviceClass;
            internal byte bDeviceSubClass;
            internal byte bDeviceProtocol;
            internal byte bMaxPacketSize0;
            internal short idVendor;
            internal short idProduct;
            internal short bcdDevice;
            internal byte iManufacturer;
            internal byte iProduct;
            internal byte iSerialNumber;
            internal byte bNumConfigurations;
        }

        //typedef struct _USB_STRING_DESCRIPTOR {
        //    UCHAR bLength;
        //    UCHAR bDescriptorType;
        //    WCHAR bString[1];
        //} USB_STRING_DESCRIPTOR, *PUSB_STRING_DESCRIPTOR;
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct UsbStringDescriptor
        {
            internal byte bLength;
            internal byte bDescriptorType;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAXIMUM_USB_STRING_LENGTH)] internal string bString;
        }

        //typedef struct _USB_DESCRIPTOR_REQUEST {
        //  ULONG ConnectionIndex;
        //  struct {
        //    UCHAR  bmRequest;
        //    UCHAR  bRequest;
        //    USHORT  wValue;
        //    USHORT  wIndex;
        //    USHORT  wLength;
        //  } SetupPacket;
        //  UCHAR  Data[0];
        //} USB_DESCRIPTOR_REQUEST, *PUSB_DESCRIPTOR_REQUEST
        [StructLayout(LayoutKind.Sequential)]
        struct UsbSetupPacket
        {
            internal byte bmRequest;
            internal byte bRequest;
            internal short wValue;
            internal short wIndex;
            internal short wLength;
        }

        [StructLayout(LayoutKind.Sequential)]
        struct UsbDescriptorRequest
        {
            internal int ConnectionIndex;

            internal UsbSetupPacket SetupPacket;
            //internal byte[] Data;
        }

        //typedef struct _USB_NODE_CONNECTION_NAME {
        //    ULONG  ConnectionIndex;
        //    ULONG  ActualLength;
        //    WCHAR  NodeName[1];
        //} USB_NODE_CONNECTION_NAME, *PUSB_NODE_CONNECTION_NAME;
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct UsbNodeConnectionName
        {
            internal int ConnectionIndex;
            internal int ActualLength;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = BUFFER_SIZE)] internal string NodeName;
        }

        //typedef struct _USB_NODE_CONNECTION_DRIVERKEY_NAME {
        //    ULONG  ConnectionIndex;
        //    ULONG  ActualLength;
        //    WCHAR  DriverKeyName[1];
        //} USB_NODE_CONNECTION_DRIVERKEY_NAME, *PUSB_NODE_CONNECTION_DRIVERKEY_NAME;
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct UsbNodeConnectionDriverkeyName // Yes, this is the same as the structure above...
        {
            internal int ConnectionIndex;
            internal int ActualLength;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = BUFFER_SIZE)] internal string DriverKeyName;
        }

        // ********************** API Definitions ************************

        //HDEVINFO SetupDiGetClassDevs(
        //  const GUID* ClassGuid,
        //  PCTSTR Enumerator,
        //  HWND hwndParent,
        //  DWORD Flags
        //);
        [DllImport("setupapi.dll", CharSet = CharSet.Auto)]
        static extern IntPtr SetupDiGetClassDevs( // 1st form using a ClassGUID
            ref Guid classGuid, int enumerator, IntPtr hwndParent, int flags);

        [DllImport("setupapi.dll", CharSet = CharSet.Auto)] // 2nd form uses an Enumerator
        static extern IntPtr SetupDiGetClassDevs(int classGuid, string enumerator, IntPtr hwndParent, int flags);

        //BOOL SetupDiEnumDeviceInterfaces(
        //  HDEVINFO DeviceInfoSet,
        //  PSP_DEVINFO_DATA DeviceInfoData,
        //  const GUID* InterfaceClassGuid,
        //  DWORD MemberIndex,
        //  PSP_DEVICE_INTERFACE_DATA DeviceInterfaceData
        //);
        [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool SetupDiEnumDeviceInterfaces(IntPtr deviceInfoSet, IntPtr deviceInfoData,
                                                       ref Guid interfaceClassGuid, int memberIndex,
                                                       ref SpDeviceInterfaceData deviceInterfaceData);

        //BOOL SetupDiGetDeviceInterfaceDetail(
        //  HDEVINFO DeviceInfoSet,
        //  PSP_DEVICE_INTERFACE_DATA DeviceInterfaceData,
        //  PSP_DEVICE_INTERFACE_DETAIL_DATA DeviceInterfaceDetailData,
        //  DWORD DeviceInterfaceDetailDataSize,
        //  PDWORD RequiredSize,
        //  PSP_DEVINFO_DATA DeviceInfoData
        //);
        [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool SetupDiGetDeviceInterfaceDetail(IntPtr deviceInfoSet,
                                                           ref SpDeviceInterfaceData deviceInterfaceData,
                                                           ref SpDeviceInterfaceDetailData
                                                               deviceInterfaceDetailData,
                                                           int deviceInterfaceDetailDataSize, ref int requiredSize,
                                                           ref SpDevinfoData deviceInfoData);

        //BOOL SetupDiGetDeviceRegistryProperty(
        //  HDEVINFO DeviceInfoSet,
        //  PSP_DEVINFO_DATA DeviceInfoData,
        //  DWORD Property,
        //  PDWORD PropertyRegDataType,
        //  PBYTE PropertyBuffer,
        //  DWORD PropertyBufferSize,
        //  PDWORD RequiredSize
        //);
        [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool SetupDiGetDeviceRegistryProperty(IntPtr deviceInfoSet, ref SpDevinfoData deviceInfoData,
                                                            int iProperty, ref int propertyRegDataType,
                                                            IntPtr propertyBuffer, int propertyBufferSize,
                                                            ref int requiredSize);

        //BOOL SetupDiEnumDeviceInfo(
        //  HDEVINFO DeviceInfoSet,
        //  DWORD MemberIndex,
        //  PSP_DEVINFO_DATA DeviceInfoData
        //);
        [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool SetupDiEnumDeviceInfo(IntPtr deviceInfoSet, int memberIndex,
                                                 ref SpDevinfoData deviceInfoData);

        //BOOL SetupDiDestroyDeviceInfoList(
        //  HDEVINFO DeviceInfoSet
        //);
        [DllImport("setupapi.dll", SetLastError = true)]
        static extern bool SetupDiDestroyDeviceInfoList(IntPtr deviceInfoSet);

        //WINSETUPAPI BOOL WINAPI  SetupDiGetDeviceInstanceId(
        //    IN HDEVINFO  DeviceInfoSet,
        //    IN PSP_DEVINFO_DATA  DeviceInfoData,
        //    OUT PTSTR  DeviceInstanceId,
        //    IN DWORD  DeviceInstanceIdSize,
        //    OUT PDWORD  RequiredSize  OPTIONAL
        //);
        [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool SetupDiGetDeviceInstanceId(IntPtr deviceInfoSet, ref SpDevinfoData deviceInfoData,
                                                      StringBuilder deviceInstanceId, int deviceInstanceIdSize,
                                                      out int requiredSize);

        //BOOL DeviceIoControl(
        //  HANDLE hDevice,
        //  DWORD dwIoControlCode,
        //  LPVOID lpInBuffer,
        //  DWORD nInBufferSize,
        //  LPVOID lpOutBuffer,
        //  DWORD nOutBufferSize,
        //  LPDWORD lpBytesReturned,
        //  LPOVERLAPPED lpOverlapped
        //);
        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool DeviceIoControl(IntPtr hDevice, int dwIoControlCode, IntPtr lpInBuffer, int nInBufferSize,
                                           IntPtr lpOutBuffer, int nOutBufferSize, out int lpBytesReturned,
                                           IntPtr lpOverlapped);

        //HANDLE CreateFile(
        //  LPCTSTR lpFileName,
        //  DWORD dwDesiredAccess,
        //  DWORD dwShareMode,
        //  LPSECURITY_ATTRIBUTES lpSecurityAttributes,
        //  DWORD dwCreationDisposition,
        //  DWORD dwFlagsAndAttributes,
        //  HANDLE hTemplateFile
        //);
        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern IntPtr CreateFile(string lpFileName, int dwDesiredAccess, int dwShareMode,
                                        IntPtr lpSecurityAttributes, int dwCreationDisposition,
                                        int dwFlagsAndAttributes, IntPtr hTemplateFile);

        //BOOL CloseHandle(
        //  HANDLE hObject
        //);
        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool CloseHandle(IntPtr hObject);
        #endregion

        // 
        // Return a list of USB Host Controllers
        // 
        static IEnumerable<UsbController> GetHostControllers()
        {
            List<UsbController> hostList = new List<UsbController>();
            Guid hostGuid = new Guid(GUID_DEVINTERFACE_HUBCONTROLLER);

            // We start at the "root" of the device tree and look for all
            // devices that match the interface GUID of a Hub Controller
            IntPtr h = SetupDiGetClassDevs(ref hostGuid, 0, IntPtr.Zero, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
            if(h.ToInt32() == INVALID_HANDLE_VALUE)
                return new ReadOnlyCollection<UsbController>(hostList);

            IntPtr ptrBuf = Marshal.AllocHGlobal(BUFFER_SIZE);
            bool success;
            int i = 0;
            do
            {
                UsbController host = new UsbController {ControllerIndex = i};

                // create a Device Interface Data structure
                SpDeviceInterfaceData dia = new SpDeviceInterfaceData();
                dia.cbSize = Marshal.SizeOf(dia);

                // start the enumeration
                success = SetupDiEnumDeviceInterfaces(h, IntPtr.Zero, ref hostGuid, i, ref dia);
                if(success)
                {
                    // build a DevInfo Data structure
                    SpDevinfoData da = new SpDevinfoData();
                    da.cbSize = Marshal.SizeOf(da);

                    // build a Device Interface Detail Data structure
                    SpDeviceInterfaceDetailData didd =
                        new SpDeviceInterfaceDetailData {cbSize = 4 + Marshal.SystemDefaultCharSize};
                    // trust me :)

                    // now we can get some more detailed information
                    int nRequiredSize = 0;
                    const int N_BYTES = BUFFER_SIZE;
                    if(SetupDiGetDeviceInterfaceDetail(h, ref dia, ref didd, N_BYTES, ref nRequiredSize, ref da))
                    {
                        host.ControllerDevicePath = didd.DevicePath;

                        // get the Device Description and DriverKeyName
                        int requiredSize = 0;
                        int regType = REG_SZ;

                        if(SetupDiGetDeviceRegistryProperty(h, ref da, SPDRP_DEVICEDESC, ref regType, ptrBuf,
                                                            BUFFER_SIZE, ref requiredSize)) host.ControllerDeviceDesc = Marshal.PtrToStringAuto(ptrBuf);
                        if(SetupDiGetDeviceRegistryProperty(h, ref da, SPDRP_DRIVER, ref regType, ptrBuf,
                                                            BUFFER_SIZE, ref requiredSize)) host.ControllerDriverKeyName = Marshal.PtrToStringAuto(ptrBuf);
                    }
                    hostList.Add(host);
                }
                i++;
            }
            while(success);

            Marshal.FreeHGlobal(ptrBuf);
            SetupDiDestroyDeviceInfoList(h);

            // convert it into a Collection
            return new ReadOnlyCollection<UsbController>(hostList);
        }

        // 
        // The USB Host Controller Class
        // 
        class UsbController
        {
            internal int ControllerIndex;
            internal string ControllerDriverKeyName, ControllerDevicePath, ControllerDeviceDesc;

            // A simple default constructor
            internal UsbController()
            {
                ControllerIndex = 0;
                ControllerDevicePath = "";
                ControllerDeviceDesc = "";
                ControllerDriverKeyName = "";
            }

            // Return the index of the instance
            internal int Index => ControllerIndex;

            // Return the Device Path, such as "\\?\pci#ven_10de&dev_005a&subsys_815a1043&rev_a2#3&267a616a&0&58#{3abf6f2d-71c4-462a-8a92-1e6861e6af27}"
            internal string DevicePath => ControllerDevicePath;

            // The DriverKeyName may be useful as a search key
            internal string DriverKeyName => ControllerDriverKeyName;

            // Return the Friendly Name, such as "VIA USB Enhanced Host Controller"
            internal string Name => ControllerDeviceDesc;

            // Return Root Hub for this Controller
            internal UsbHub GetRootHub()
            {
                IntPtr h, h2;
                UsbHub root = new UsbHub {HubIsRootHub = true, HubDeviceDesc = "Root Hub"};

                // Open a handle to the Host Controller
                h = CreateFile(ControllerDevicePath, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0,
                               IntPtr.Zero);
                if(h.ToInt32() == INVALID_HANDLE_VALUE) return root;

                UsbRootHubName hubName = new UsbRootHubName();
                int nBytes = Marshal.SizeOf(hubName);
                IntPtr ptrHubName = Marshal.AllocHGlobal(nBytes);

                // get the Hub Name
                if(DeviceIoControl(h, IOCTL_USB_GET_ROOT_HUB_NAME, ptrHubName, nBytes, ptrHubName, nBytes,
                                   out _, IntPtr.Zero))
                {
                    hubName = (UsbRootHubName)Marshal.PtrToStructure(ptrHubName, typeof(UsbRootHubName));
                    root.HubDevicePath = @"\\.\" + hubName.RootHubName;
                }

                // TODO: Get DriverKeyName for Root Hub

                // Now let's open the Hub (based upon the HubName we got above)
                h2 = CreateFile(root.HubDevicePath, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0,
                                IntPtr.Zero);
                if(h2.ToInt32() != INVALID_HANDLE_VALUE)
                {
                    UsbNodeInformation nodeInfo = new UsbNodeInformation {NodeType = (int)UsbHubNode.UsbHub};
                    nBytes = Marshal.SizeOf(nodeInfo);
                    IntPtr ptrNodeInfo = Marshal.AllocHGlobal(nBytes);
                    Marshal.StructureToPtr(nodeInfo, ptrNodeInfo, true);

                    // get the Hub Information
                    if(DeviceIoControl(h2, IOCTL_USB_GET_NODE_INFORMATION, ptrNodeInfo, nBytes, ptrNodeInfo, nBytes,
                                       out _, IntPtr.Zero))
                    {
                        nodeInfo = (UsbNodeInformation)Marshal.PtrToStructure(ptrNodeInfo,
                                                                              typeof(UsbNodeInformation));
                        root.HubIsBusPowered = Convert.ToBoolean(nodeInfo.HubInformation.HubIsBusPowered);
                        root.HubPortCount = nodeInfo.HubInformation.HubDescriptor.bNumberOfPorts;
                    }
                    Marshal.FreeHGlobal(ptrNodeInfo);
                    CloseHandle(h2);
                }

                Marshal.FreeHGlobal(ptrHubName);
                CloseHandle(h);
                return root;
            }
        }

        // 
        // The Hub class
        // 
        internal class UsbHub
        {
            internal int HubPortCount;
            internal string HubDriverKey, HubDevicePath, HubDeviceDesc;
            internal string HubManufacturer, HubProduct, HubSerialNumber, HubInstanceId;
            internal bool HubIsBusPowered, HubIsRootHub;

            // a simple default constructor
            internal UsbHub()
            {
                HubPortCount = 0;
                HubDevicePath = "";
                HubDeviceDesc = "";
                HubDriverKey = "";
                HubIsBusPowered = false;
                HubIsRootHub = false;
                HubManufacturer = "";
                HubProduct = "";
                HubSerialNumber = "";
                HubInstanceId = "";
            }

            // return Port Count
            internal int PortCount => HubPortCount;

            // return the Device Path, such as "\\?\pci#ven_10de&dev_005a&subsys_815a1043&rev_a2#3&267a616a&0&58#{3abf6f2d-71c4-462a-8a92-1e6861e6af27}"
            internal string DevicePath => HubDevicePath;

            // The DriverKey may be useful as a search key
            internal string DriverKey => HubDriverKey;

            // return the Friendly Name, such as "VIA USB Enhanced Host Controller"
            internal string Name => HubDeviceDesc;

            // the device path of this device
            internal string InstanceId => HubInstanceId;

            // is is this a self-powered hub?
            internal bool IsBusPowered => HubIsBusPowered;

            // is this a root hub?
            internal bool IsRootHub => HubIsRootHub;

            internal string Manufacturer => HubManufacturer;

            internal string Product => HubProduct;

            internal string SerialNumber => HubSerialNumber;

            // return a list of the down stream ports
            internal IEnumerable<UsbPort> GetPorts()
            {
                List<UsbPort> portList = new List<UsbPort>();

                // Open a handle to the Hub device
                IntPtr h = CreateFile(HubDevicePath, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0,
                                      IntPtr.Zero);
                if(h.ToInt32() == INVALID_HANDLE_VALUE)
                    return new ReadOnlyCollection<UsbPort>(portList);

                int nBytes = Marshal.SizeOf(typeof(UsbNodeConnectionInformationEx));
                IntPtr ptrNodeConnection = Marshal.AllocHGlobal(nBytes);

                // loop thru all of the ports on the hub
                // BTW: Ports are numbered starting at 1
                for(int i = 1; i <= HubPortCount; i++)
                {
                    UsbNodeConnectionInformationEx nodeConnection =
                        new UsbNodeConnectionInformationEx {ConnectionIndex = i};
                    Marshal.StructureToPtr(nodeConnection, ptrNodeConnection, true);

                    if(!DeviceIoControl(h, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX, ptrNodeConnection, nBytes,
                                        ptrNodeConnection, nBytes, out _, IntPtr.Zero)) continue;

                    nodeConnection =
                        (UsbNodeConnectionInformationEx)Marshal.PtrToStructure(ptrNodeConnection,
                                                                               typeof(
                                                                                   UsbNodeConnectionInformationEx
                                                                               ));

                    // load up the USBPort class
                    UsbPort port = new UsbPort
                    {
                        PortPortNumber = i,
                        PortHubDevicePath = HubDevicePath,
                        PortStatus = ((UsbConnectionStatus)nodeConnection.ConnectionStatus).ToString(),
                        PortSpeed = ((UsbDeviceSpeed)nodeConnection.Speed).ToString(),
                        PortIsDeviceConnected =
                            nodeConnection.ConnectionStatus == (int)UsbConnectionStatus.DeviceConnected,
                        PortIsHub = Convert.ToBoolean(nodeConnection.DeviceIsHub),
                        PortDeviceDescriptor = nodeConnection.DeviceDescriptor
                    };

                    // add it to the list
                    portList.Add(port);
                }

                Marshal.FreeHGlobal(ptrNodeConnection);
                CloseHandle(h);
                // convert it into a Collection
                return new ReadOnlyCollection<UsbPort>(portList);
            }
        }

        // 
        // The Port Class
        // 
        internal class UsbPort
        {
            internal int PortPortNumber;
            internal string PortStatus, PortHubDevicePath, PortSpeed;
            internal bool PortIsHub, PortIsDeviceConnected;
            internal UsbDeviceDescriptor PortDeviceDescriptor;

            // a simple default constructor
            internal UsbPort()
            {
                PortPortNumber = 0;
                PortStatus = "";
                PortHubDevicePath = "";
                PortSpeed = "";
                PortIsHub = false;
                PortIsDeviceConnected = false;
            }

            // return Port Index of the Hub
            internal int PortNumber => PortPortNumber;

            // return the Device Path of the Hub
            internal string HubDevicePath => PortHubDevicePath;

            // the status (see USB_CONNECTION_STATUS above)
            internal string Status => PortStatus;

            // the speed of the connection (see USB_DEVICE_SPEED above)
            internal string Speed => PortSpeed;

            // is this a downstream external hub?
            internal bool IsHub => PortIsHub;

            // is anybody home?
            internal bool IsDeviceConnected => PortIsDeviceConnected;

            // return a down stream external hub
            internal UsbDevice GetDevice()
            {
                if(!PortIsDeviceConnected) return null;

                // Copy over some values from the Port class
                // Ya know, I've given some thought about making Device a derived class...
                UsbDevice device = new UsbDevice
                {
                    DevicePortNumber = PortPortNumber,
                    DeviceHubDevicePath = PortHubDevicePath,
                    DeviceDescriptor = PortDeviceDescriptor
                };

                // Open a handle to the Hub device
                IntPtr h = CreateFile(PortHubDevicePath, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0,
                                      IntPtr.Zero);
                if(h.ToInt32() == INVALID_HANDLE_VALUE) return device;

                int nBytesReturned;
                int nBytes = BUFFER_SIZE;
                // We use this to zero fill a buffer
                string nullString = new string((char)0, BUFFER_SIZE / Marshal.SystemDefaultCharSize);

                // The iManufacturer, iProduct and iSerialNumber entries in the
                // Device Descriptor are really just indexes.  So, we have to
                // request a String Descriptor to get the values for those strings.

                if(PortDeviceDescriptor.iManufacturer > 0)
                {
                    // build a request for string descriptor
                    UsbDescriptorRequest request = new UsbDescriptorRequest
                    {
                        ConnectionIndex = PortPortNumber,
                        SetupPacket =
                        {
                            // Language Code
                            wIndex = 0x409,
                            wValue = (short)((USB_STRING_DESCRIPTOR_TYPE << 8) + PortDeviceDescriptor.iManufacturer)
                        }
                    };
                    request.SetupPacket.wLength = (short)(nBytes - Marshal.SizeOf(request));
                    // Geez, I wish C# had a Marshal.MemSet() method
                    IntPtr ptrRequest = Marshal.StringToHGlobalAuto(nullString);
                    Marshal.StructureToPtr(request, ptrRequest, true);

                    // Use an IOCTL call to request the String Descriptor
                    if(DeviceIoControl(h, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, ptrRequest, nBytes,
                                       ptrRequest, nBytes, out nBytesReturned, IntPtr.Zero))
                    {
                        // The location of the string descriptor is immediately after
                        // the Request structure.  Because this location is not "covered"
                        // by the structure allocation, we're forced to zero out this
                        // chunk of memory by using the StringToHGlobalAuto() hack above
                        IntPtr ptrStringDesc = new IntPtr(ptrRequest.ToInt32() + Marshal.SizeOf(request));
                        UsbStringDescriptor stringDesc =
                            (UsbStringDescriptor)Marshal.PtrToStructure(ptrStringDesc,
                                                                        typeof(UsbStringDescriptor));
                        device.DeviceManufacturer = stringDesc.bString;
                    }
                    Marshal.FreeHGlobal(ptrRequest);
                }
                if(PortDeviceDescriptor.iProduct > 0)
                {
                    // build a request for string descriptor
                    UsbDescriptorRequest request = new UsbDescriptorRequest
                    {
                        ConnectionIndex = PortPortNumber,
                        SetupPacket =
                        {
                            // Language Code
                            wIndex = 0x409,
                            wValue = (short)((USB_STRING_DESCRIPTOR_TYPE << 8) + PortDeviceDescriptor.iProduct)
                        }
                    };
                    request.SetupPacket.wLength = (short)(nBytes - Marshal.SizeOf(request));
                    // Geez, I wish C# had a Marshal.MemSet() method
                    IntPtr ptrRequest = Marshal.StringToHGlobalAuto(nullString);
                    Marshal.StructureToPtr(request, ptrRequest, true);

                    // Use an IOCTL call to request the String Descriptor
                    if(DeviceIoControl(h, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, ptrRequest, nBytes,
                                       ptrRequest, nBytes, out nBytesReturned, IntPtr.Zero))
                    {
                        // the location of the string descriptor is immediately after the Request structure
                        IntPtr ptrStringDesc = new IntPtr(ptrRequest.ToInt32() + Marshal.SizeOf(request));
                        UsbStringDescriptor stringDesc =
                            (UsbStringDescriptor)Marshal.PtrToStructure(ptrStringDesc,
                                                                        typeof(UsbStringDescriptor));
                        device.DeviceProduct = stringDesc.bString;
                    }
                    Marshal.FreeHGlobal(ptrRequest);
                }
                if(PortDeviceDescriptor.iSerialNumber > 0)
                {
                    // build a request for string descriptor
                    UsbDescriptorRequest request = new UsbDescriptorRequest
                    {
                        ConnectionIndex = PortPortNumber,
                        SetupPacket =
                        {
                            // Language Code
                            wIndex = 0x409,
                            wValue = (short)((USB_STRING_DESCRIPTOR_TYPE << 8) + PortDeviceDescriptor.iSerialNumber)
                        }
                    };
                    request.SetupPacket.wLength = (short)(nBytes - Marshal.SizeOf(request));
                    // Geez, I wish C# had a Marshal.MemSet() method
                    IntPtr ptrRequest = Marshal.StringToHGlobalAuto(nullString);
                    Marshal.StructureToPtr(request, ptrRequest, true);

                    // Use an IOCTL call to request the String Descriptor
                    if(DeviceIoControl(h, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, ptrRequest, nBytes,
                                       ptrRequest, nBytes, out nBytesReturned, IntPtr.Zero))
                    {
                        // the location of the string descriptor is immediately after the Request structure
                        IntPtr ptrStringDesc = new IntPtr(ptrRequest.ToInt32() + Marshal.SizeOf(request));
                        UsbStringDescriptor stringDesc =
                            (UsbStringDescriptor)Marshal.PtrToStructure(ptrStringDesc,
                                                                        typeof(UsbStringDescriptor));
                        device.DeviceSerialNumber = stringDesc.bString;
                    }
                    Marshal.FreeHGlobal(ptrRequest);
                }

                // build a request for configuration descriptor
                UsbDescriptorRequest dcrRequest = new UsbDescriptorRequest
                {
                    ConnectionIndex = PortPortNumber,
                    SetupPacket = {wIndex = 0, wValue = USB_CONFIGURATION_DESCRIPTOR_TYPE << 8}
                };
                dcrRequest.SetupPacket.wLength = (short)(nBytes - Marshal.SizeOf(dcrRequest));
                // Geez, I wish C# had a Marshal.MemSet() method
                IntPtr dcrPtrRequest = Marshal.StringToHGlobalAuto(nullString);
                Marshal.StructureToPtr(dcrRequest, dcrPtrRequest, true);

                // Use an IOCTL call to request the String Descriptor
                if(DeviceIoControl(h, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, dcrPtrRequest, nBytes,
                                   dcrPtrRequest, nBytes, out nBytesReturned, IntPtr.Zero))
                {
                    IntPtr ptrStringDesc = new IntPtr(dcrPtrRequest.ToInt32() + Marshal.SizeOf(dcrRequest));
                    device.BinaryDeviceDescriptors = new byte[nBytesReturned];
                    Marshal.Copy(ptrStringDesc, device.BinaryDeviceDescriptors, 0, nBytesReturned);
                }
                Marshal.FreeHGlobal(dcrPtrRequest);

                // Get the Driver Key Name (usefull in locating a device)
                UsbNodeConnectionDriverkeyName driverKey =
                    new UsbNodeConnectionDriverkeyName {ConnectionIndex = PortPortNumber};
                nBytes = Marshal.SizeOf(driverKey);
                IntPtr ptrDriverKey = Marshal.AllocHGlobal(nBytes);
                Marshal.StructureToPtr(driverKey, ptrDriverKey, true);

                // Use an IOCTL call to request the Driver Key Name
                if(DeviceIoControl(h, IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME, ptrDriverKey, nBytes,
                                   ptrDriverKey, nBytes, out nBytesReturned, IntPtr.Zero))
                {
                    driverKey = (UsbNodeConnectionDriverkeyName)Marshal.PtrToStructure(ptrDriverKey,
                                                                                       typeof(
                                                                                           UsbNodeConnectionDriverkeyName
                                                                                       ));
                    device.DeviceDriverKey = driverKey.DriverKeyName;

                    // use the DriverKeyName to get the Device Description and Instance ID
                    device.DeviceName = GetDescriptionByKeyName(device.DeviceDriverKey);
                    device.DeviceInstanceId = GetInstanceIdByKeyName(device.DeviceDriverKey);
                }
                Marshal.FreeHGlobal(ptrDriverKey);
                CloseHandle(h);
                return device;
            }

            // return a down stream external hub
            internal UsbHub GetHub()
            {
                if(!PortIsHub) return null;

                UsbHub hub = new UsbHub();
                IntPtr h, h2;
                hub.HubIsRootHub = false;
                hub.HubDeviceDesc = "External Hub";

                // Open a handle to the Host Controller
                h = CreateFile(PortHubDevicePath, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0,
                               IntPtr.Zero);
                if(h.ToInt32() == INVALID_HANDLE_VALUE) return hub;
                // Get the DevicePath for downstream hub
                UsbNodeConnectionName nodeName = new UsbNodeConnectionName {ConnectionIndex = PortPortNumber};
                int nBytes = Marshal.SizeOf(nodeName);
                IntPtr ptrNodeName = Marshal.AllocHGlobal(nBytes);
                Marshal.StructureToPtr(nodeName, ptrNodeName, true);

                // Use an IOCTL call to request the Node Name
                if(DeviceIoControl(h, IOCTL_USB_GET_NODE_CONNECTION_NAME, ptrNodeName, nBytes, ptrNodeName, nBytes,
                                   out _, IntPtr.Zero))
                {
                    nodeName = (UsbNodeConnectionName)Marshal.PtrToStructure(ptrNodeName,
                                                                             typeof(UsbNodeConnectionName));
                    hub.HubDevicePath = @"\\.\" + nodeName.NodeName;
                }

                // Now let's open the Hub (based upon the HubName we got above)
                h2 = CreateFile(hub.HubDevicePath, GENERIC_WRITE, FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0,
                                IntPtr.Zero);
                if(h2.ToInt32() != INVALID_HANDLE_VALUE)
                {
                    UsbNodeInformation nodeInfo = new UsbNodeInformation {NodeType = (int)UsbHubNode.UsbHub};
                    nBytes = Marshal.SizeOf(nodeInfo);
                    IntPtr ptrNodeInfo = Marshal.AllocHGlobal(nBytes);
                    Marshal.StructureToPtr(nodeInfo, ptrNodeInfo, true);

                    // get the Hub Information
                    if(DeviceIoControl(h2, IOCTL_USB_GET_NODE_INFORMATION, ptrNodeInfo, nBytes, ptrNodeInfo, nBytes,
                                       out _, IntPtr.Zero))
                    {
                        nodeInfo = (UsbNodeInformation)Marshal.PtrToStructure(ptrNodeInfo,
                                                                              typeof(UsbNodeInformation));
                        hub.HubIsBusPowered = Convert.ToBoolean(nodeInfo.HubInformation.HubIsBusPowered);
                        hub.HubPortCount = nodeInfo.HubInformation.HubDescriptor.bNumberOfPorts;
                    }
                    Marshal.FreeHGlobal(ptrNodeInfo);
                    CloseHandle(h2);
                }

                // Fill in the missing Manufacture, Product, and SerialNumber values
                // values by just creating a Device instance and copying the values
                UsbDevice device = GetDevice();
                hub.HubInstanceId = device.DeviceInstanceId;
                hub.HubManufacturer = device.Manufacturer;
                hub.HubProduct = device.Product;
                hub.HubSerialNumber = device.SerialNumber;
                hub.HubDriverKey = device.DriverKey;

                Marshal.FreeHGlobal(ptrNodeName);
                CloseHandle(h);
                return hub;
            }
        }

        // 
        // The USB Device Class
        // 
        internal class UsbDevice
        {
            internal int DevicePortNumber;
            internal string DeviceDriverKey, DeviceHubDevicePath, DeviceInstanceId, DeviceName;
            internal string DeviceManufacturer, DeviceProduct, DeviceSerialNumber;
            internal UsbDeviceDescriptor DeviceDescriptor;
            internal byte[] BinaryDeviceDescriptors;

            // a simple default constructor
            internal UsbDevice()
            {
                DevicePortNumber = 0;
                DeviceHubDevicePath = "";
                DeviceDriverKey = "";
                DeviceManufacturer = "";
                DeviceProduct = "Unknown USB Device";
                DeviceSerialNumber = "";
                DeviceName = "";
                DeviceInstanceId = "";
                BinaryDeviceDescriptors = null;
            }

            // return Port Index of the Hub
            internal int PortNumber => DevicePortNumber;

            // return the Device Path of the Hub (the parent device)
            internal string HubDevicePath => DeviceHubDevicePath;

            // useful as a search key
            internal string DriverKey => DeviceDriverKey;

            // the device path of this device
            internal string InstanceId => DeviceInstanceId;

            // the friendly name
            internal string Name => DeviceName;

            internal string Manufacturer => DeviceManufacturer;

            internal string Product => DeviceProduct;

            internal string SerialNumber => DeviceSerialNumber;

            internal byte[] BinaryDescriptors => BinaryDeviceDescriptors;
        }

        // 
        // private function for finding a USB device's Description
        // 
        static string GetDescriptionByKeyName(string driverKeyName)
        {
            string ans = "";
            const string DEV_ENUM = REGSTR_KEY_USB;

            // Use the "enumerator form" of the SetupDiGetClassDevs API
            // to generate a list of all USB devices
            IntPtr h = SetupDiGetClassDevs(0, DEV_ENUM, IntPtr.Zero, DIGCF_PRESENT | DIGCF_ALLCLASSES);
            if(h.ToInt32() == INVALID_HANDLE_VALUE) return ans;

            IntPtr ptrBuf = Marshal.AllocHGlobal(BUFFER_SIZE);

            bool success;
            int i = 0;
            do
            {
                // create a Device Interface Data structure
                SpDevinfoData da = new SpDevinfoData();
                da.cbSize = Marshal.SizeOf(da);

                // start the enumeration
                success = SetupDiEnumDeviceInfo(h, i, ref da);
                if(success)
                {
                    int requiredSize = 0;
                    int regType = REG_SZ;
                    string keyName = "";

                    if(SetupDiGetDeviceRegistryProperty(h, ref da, SPDRP_DRIVER, ref regType, ptrBuf, BUFFER_SIZE,
                                                        ref requiredSize)) keyName = Marshal.PtrToStringAuto(ptrBuf);

                    // is it a match?
                    if(keyName == driverKeyName)
                    {
                        if(SetupDiGetDeviceRegistryProperty(h, ref da, SPDRP_DEVICEDESC, ref regType, ptrBuf,
                                                            BUFFER_SIZE, ref requiredSize)) ans = Marshal.PtrToStringAuto(ptrBuf);
                        break;
                    }
                }

                i++;
            }
            while(success);

            Marshal.FreeHGlobal(ptrBuf);
            SetupDiDestroyDeviceInfoList(h);

            return ans;
        }

        // 
        // private function for finding a USB device's Instance ID
        // 
        static string GetInstanceIdByKeyName(string driverKeyName)
        {
            string ans = "";
            const string DEV_ENUM = REGSTR_KEY_USB;

            // Use the "enumerator form" of the SetupDiGetClassDevs API
            // to generate a list of all USB devices
            IntPtr h = SetupDiGetClassDevs(0, DEV_ENUM, IntPtr.Zero, DIGCF_PRESENT | DIGCF_ALLCLASSES);
            if(h.ToInt32() == INVALID_HANDLE_VALUE) return ans;

            IntPtr ptrBuf = Marshal.AllocHGlobal(BUFFER_SIZE);

            bool success;
            int i = 0;
            do
            {
                // create a Device Interface Data structure
                SpDevinfoData da = new SpDevinfoData();
                da.cbSize = Marshal.SizeOf(da);

                // start the enumeration
                success = SetupDiEnumDeviceInfo(h, i, ref da);
                if(success)
                {
                    int requiredSize = 0;
                    int regType = REG_SZ;

                    string keyName = "";
                    if(SetupDiGetDeviceRegistryProperty(h, ref da, SPDRP_DRIVER, ref regType, ptrBuf, BUFFER_SIZE,
                                                        ref requiredSize)) keyName = Marshal.PtrToStringAuto(ptrBuf);

                    // is it a match?
                    if(keyName == driverKeyName)
                    {
                        const int N_BYTES = BUFFER_SIZE;
                        StringBuilder sb = new StringBuilder(N_BYTES);
                        SetupDiGetDeviceInstanceId(h, ref da, sb, N_BYTES, out requiredSize);
                        ans = sb.ToString();
                        break;
                    }
                }

                i++;
            }
            while(success);

            Marshal.FreeHGlobal(ptrBuf);
            SetupDiDestroyDeviceInfoList(h);

            return ans;
        }
    }
}