Figuring which printer name corresponds to which device ID

Question

My goal is to open a printer connected via USB using the CreateFile (and then issue some WriteFiles and ReadFiles).

If the pri

Answer 1

Below is what I finally have been able to come up with.

Please confirm that SYSTEM\CurrentControlSet\Control\Print\Printers\{0}\PNPData is a supported path, and not just happens to be there in the current implementation, subject to future changes.

There's a little problem with structure alignment, for which I've posted a separate question.

public static class UsbPrinterResolver
{

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    private struct SP_DEVINFO_DATA
    {
        public uint cbSize;
        public Guid ClassGuid;
        public uint DevInst;
        public IntPtr Reserved;
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    private struct SP_DEVICE_INTERFACE_DATA
    {
        public uint cbSize;
        public Guid InterfaceClassGuid;
        public uint Flags;
        public IntPtr Reserved;
    }


    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
    private struct SP_DEVICE_INTERFACE_DETAIL_DATA  // Only used for Marshal.SizeOf. NOT!
    {
        public uint cbSize;
        public char DevicePath;
    }


    [DllImport("cfgmgr32.dll", CharSet = CharSet.Auto, SetLastError = false, ExactSpelling = true)]
    private static extern uint CM_Get_Parent(out uint pdnDevInst, uint dnDevInst, uint ulFlags);

    [DllImport("cfgmgr32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    private static extern uint CM_Get_Device_ID(uint dnDevInst, string Buffer, uint BufferLen, uint ulFlags);

    [DllImport("cfgmgr32.dll", CharSet = CharSet.Auto, SetLastError = false, ExactSpelling = true)]
    private static extern uint CM_Get_Device_ID_Size(out uint pulLen, uint dnDevInst, uint ulFlags);

    [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetupDiGetClassDevs([In(), MarshalAs(UnmanagedType.LPStruct)] System.Guid ClassGuid, string Enumerator, IntPtr hwndParent, uint Flags);

    [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern int SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet, uint MemberIndex, ref SP_DEVINFO_DATA DeviceInfoData);

    [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern int SetupDiEnumDeviceInterfaces(IntPtr DeviceInfoSet, [In()] ref SP_DEVINFO_DATA DeviceInfoData, [In(), MarshalAs(UnmanagedType.LPStruct)] System.Guid InterfaceClassGuid, uint MemberIndex, ref SP_DEVICE_INTERFACE_DATA DeviceInterfaceData);

    [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern int SetupDiGetDeviceInterfaceDetail(IntPtr DeviceInfoSet, [In()] ref SP_DEVICE_INTERFACE_DATA DeviceInterfaceData, IntPtr DeviceInterfaceDetailData, uint DeviceInterfaceDetailDataSize, out uint RequiredSize, IntPtr DeviceInfoData);

    [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
    private static extern int SetupDiDestroyDeviceInfoList(IntPtr DeviceInfoSet);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
    private static extern IntPtr CreateFile(string lpFileName, uint dwDesiredAccess, int dwShareMode, IntPtr lpSecurityAttributes, int dwCreationDisposition, int dwFlagsAndAttributes, IntPtr hTemplateFile);

    private const uint DIGCF_PRESENT = 0x00000002U;
    private const uint DIGCF_DEVICEINTERFACE = 0x00000010U;
    private const int ERROR_INSUFFICIENT_BUFFER = 122;
    private const uint CR_SUCCESS = 0;

    private const int FILE_SHARE_READ = 1;
    private const int FILE_SHARE_WRITE = 2;
    private const uint GENERIC_READ = 0x80000000;
    private const uint GENERIC_WRITE = 0x40000000;
    private const int OPEN_EXISTING = 3;

    private static readonly Guid GUID_PRINTER_INSTALL_CLASS = new Guid(0x4d36e979, 0xe325, 0x11ce, 0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1, 0x03, 0x18);
    private static readonly Guid GUID_DEVINTERFACE_USBPRINT = new Guid(0x28d78fad, 0x5a12, 0x11D1, 0xae, 0x5b, 0x00, 0x00, 0xf8, 0x03, 0xa8, 0xc2);
    private static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);


    private static string GetPrinterRegistryInstanceID(string PrinterName) {
        if (string.IsNullOrEmpty(PrinterName)) throw new ArgumentNullException("PrinterName");

        const string key_template = @"SYSTEM\CurrentControlSet\Control\Print\Printers\{0}\PNPData";

        using (var hk = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(
                            string.Format(key_template, PrinterName),
                            Microsoft.Win32.RegistryKeyPermissionCheck.Default,
                            System.Security.AccessControl.RegistryRights.QueryValues
                        )
               )
        {

            if (hk == null) throw new ArgumentOutOfRangeException("PrinterName", "This printer does not have PnP data.");

            return (string)hk.GetValue("DeviceInstanceId");
        }
    }

    private static string GetPrinterParentDeviceId(string RegistryInstanceID) {
        if (string.IsNullOrEmpty(RegistryInstanceID)) throw new ArgumentNullException("RegistryInstanceID");

        IntPtr hdi = SetupDiGetClassDevs(GUID_PRINTER_INSTALL_CLASS, RegistryInstanceID, IntPtr.Zero, DIGCF_PRESENT);
        if (hdi.Equals(INVALID_HANDLE_VALUE)) throw new System.ComponentModel.Win32Exception();

        try
        {
            SP_DEVINFO_DATA printer_data = new SP_DEVINFO_DATA();
            printer_data.cbSize = (uint)Marshal.SizeOf(typeof(SP_DEVINFO_DATA));

            if (SetupDiEnumDeviceInfo(hdi, 0, ref printer_data) == 0) throw new System.ComponentModel.Win32Exception();   // Only one device in the set

            uint cmret = 0;

            uint parent_devinst = 0;
            cmret = CM_Get_Parent(out parent_devinst, printer_data.DevInst, 0);
            if (cmret != CR_SUCCESS) throw new Exception(string.Format("Failed to get parent of the device '{0}'. Error code: 0x{1:X8}", RegistryInstanceID, cmret));


            uint parent_device_id_size = 0;
            cmret = CM_Get_Device_ID_Size(out parent_device_id_size, parent_devinst, 0);
            if (cmret != CR_SUCCESS) throw new Exception(string.Format("Failed to get size of the device ID of the parent of the device '{0}'. Error code: 0x{1:X8}", RegistryInstanceID, cmret));

            parent_device_id_size++;  // To include the null character

            string parent_device_id = new string('\0', (int)parent_device_id_size);
            cmret = CM_Get_Device_ID(parent_devinst, parent_device_id, parent_device_id_size, 0);
            if (cmret != CR_SUCCESS) throw new Exception(string.Format("Failed to get device ID of the parent of the device '{0}'. Error code: 0x{1:X8}", RegistryInstanceID, cmret));

            return parent_device_id;
        }
        finally
        {
            SetupDiDestroyDeviceInfoList(hdi);
        }
    }

    private static string GetUSBInterfacePath(string SystemDeviceInstanceID) {
        if (string.IsNullOrEmpty(SystemDeviceInstanceID)) throw new ArgumentNullException("SystemDeviceInstanceID");

        IntPtr hdi = SetupDiGetClassDevs(GUID_DEVINTERFACE_USBPRINT, SystemDeviceInstanceID, IntPtr.Zero, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
        if (hdi.Equals(INVALID_HANDLE_VALUE)) throw new System.ComponentModel.Win32Exception();

        try
        {
            SP_DEVINFO_DATA device_data = new SP_DEVINFO_DATA();
            device_data.cbSize = (uint)Marshal.SizeOf(typeof(SP_DEVINFO_DATA));

            if (SetupDiEnumDeviceInfo(hdi, 0, ref device_data) == 0) throw new System.ComponentModel.Win32Exception();  // Only one device in the set

            SP_DEVICE_INTERFACE_DATA interface_data = new SP_DEVICE_INTERFACE_DATA();
            interface_data.cbSize = (uint)Marshal.SizeOf(typeof(SP_DEVICE_INTERFACE_DATA));

            if (SetupDiEnumDeviceInterfaces(hdi, ref device_data, GUID_DEVINTERFACE_USBPRINT, 0, ref interface_data) == 0) throw new System.ComponentModel.Win32Exception();   // Only one interface in the set


            // Get required buffer size
            uint required_size = 0;
            SetupDiGetDeviceInterfaceDetail(hdi, ref interface_data, IntPtr.Zero, 0, out required_size, IntPtr.Zero);

            int last_error_code = Marshal.GetLastWin32Error();
            if (last_error_code != ERROR_INSUFFICIENT_BUFFER) throw new System.ComponentModel.Win32Exception(last_error_code);

            IntPtr interface_detail_data = Marshal.AllocCoTaskMem((int)required_size);

            try
            {

                // FIXME, don't know how to calculate the size.
                // See https://stackoverflow.com/questions/10728644/properly-declare-sp-device-interface-detail-data-for-pinvoke

                switch (IntPtr.Size)
                {
                    case 4:
                        Marshal.WriteInt32(interface_detail_data, 4 + Marshal.SystemDefaultCharSize);
                        break;
                    case 8:
                        Marshal.WriteInt32(interface_detail_data, 8);
                        break;

                    default:
                        throw new NotSupportedException("Architecture not supported.");
                }

                if (SetupDiGetDeviceInterfaceDetail(hdi, ref interface_data, interface_detail_data, required_size, out required_size, IntPtr.Zero) == 0) throw new System.ComponentModel.Win32Exception();

                // TODO: When upgrading to .NET 4, replace that with IntPtr.Add
                return Marshal.PtrToStringAuto(new IntPtr(interface_detail_data.ToInt64() + Marshal.OffsetOf(typeof(SP_DEVICE_INTERFACE_DETAIL_DATA), "DevicePath").ToInt64()));

            }
            finally
            {
                Marshal.FreeCoTaskMem(interface_detail_data);
            }
        }
        finally
        {
            SetupDiDestroyDeviceInfoList(hdi);
        }
    }


    public static string GetUSBPath(string PrinterName) {
        return GetUSBInterfacePath(GetPrinterParentDeviceId(GetPrinterRegistryInstanceID(PrinterName)));
    }

    public static Microsoft.Win32.SafeHandles.SafeFileHandle OpenUSBPrinter(string PrinterName) {
        return new Microsoft.Win32.SafeHandles.SafeFileHandle(CreateFile(GetUSBPath(PrinterName), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero), true);
    }

}

Usage:

using (var sh = UsbPrinterResolver.OpenUSBPrinter("Zebra Large"))
{
    using (var f = new System.IO.FileStream(sh, System.IO.FileAccess.ReadWrite))
    {
        // Read from and write to the stream f
    }
}