public override unsafe string GetDeviceString(int index)
{
ushort stringIndex(byte index) => (ushort)((((byte)NativeMethods.DESCRIPTOR_TYPE.STRING) << 8) | index);
void closeDev(NativeMethods.IOUSBDeviceStruct182 **usbDev)
{
(*usbDev)->USBDeviceClose(usbDev);
(*usbDev)->Release(usbDev);
}
// Setup the packet for retrieving supported langId
var setup = new NativeMethods.IOUSBDevRequest
{
bmRequestType = (byte)NativeMethods.ENDPOINT_DIRECTION.IN,
bRequest = (byte)NativeMethods.STANDARD_REQUEST.GET_DESCRIPTOR,
wValue = stringIndex(0),
wIndex = 0,
wLength = 255
};
int kernRet = NativeMethods.IOMasterPort(0, out uint masterPort);
if (kernRet != 0)
{
throw new Exception($"Failed to get IOMasterPort: {kernRet:X}");
}
// Determine USB device from HID path
var hidEntry = NativeMethods.IORegistryEntryFromPath(masterPort, ref _path).ToIOObject();
int deviceEntry = 0;
IntPtr kIOUSBDeviceInterfaceID = NativeMethods.kIOUSBDeviceInterfaceID;
if (hidEntry.IsSet)
{
NativeMethods.IORegistryEntryGetParentEntry(hidEntry, "IOService", out var interfaceEntry);
if (interfaceEntry != 0)
{
NativeMethods.IORegistryEntryGetParentEntry(interfaceEntry, "IOService", out deviceEntry);
}
}
if (deviceEntry == 0)
{
throw new Exception("Failed retrieving USB Device");
}
var err = NativeMethods.IOCreatePlugInInterfaceForService(deviceEntry,
NativeMethods.kIOUSBDeviceUserClientTypeID, NativeMethods.kIOCFPluginInterfaceID,
out var pluginInterface, out var score);
if (err != NativeMethods.IOReturn.Success)
{
throw new Exception($"Plugin Interface creation failed. 0x{err:X}");
}
(*pluginInterface)->QueryInterface(pluginInterface, NativeMethods.CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID), out var usbDevPtr);
(*pluginInterface)->Release(pluginInterface);
if (usbDevPtr != null)
{
var usbDev = (NativeMethods.IOUSBDeviceStruct182 * *)usbDevPtr;
err = (*usbDev)->USBDeviceOpen(usbDev);
if (err != NativeMethods.IOReturn.Success)
{
(*usbDev)->Release(usbDev);
throw new DeviceIOException(this, $"Failed to open USB device: 0x{err:X}");
}
fixed(char *sbuf = new char[255])
{
setup.pData = sbuf;
err = (*usbDev)->DeviceRequest(usbDev, &setup);
if (err != NativeMethods.IOReturn.Success)
{
closeDev(usbDev);
throw new DeviceIOException(this, $"DeviceRequest failed: 0x{err:X}");
}
var buf = (byte *)setup.pData;
ushort langId = (ushort)(buf[2] | buf[3] << 8);
for (int i = 0; i < 255; i++)
{
buf[i] = 0;
}
// Retrieve string
setup.wIndex = langId;
setup.wValue = stringIndex((byte)index);
(*usbDev)->DeviceRequest(usbDev, &setup);
if (err != NativeMethods.IOReturn.Success)
{
closeDev(usbDev);
throw new DeviceIOException(this, $"DeviceRequest failed: 0x{err:X}");
}
var deviceString = new StringBuilder(255);
var ssbuf = (char *)setup.pData;
for (int i = 1; i < 255; i++)
{
var c = ssbuf[i];
if (c == 0)
{
break;
}
else
{
deviceString.Append(c);
}
}
closeDev(usbDev);
return(deviceString.ToString());
}
}
else
{
throw new DeviceIOException(this, $"USB Device interface retrieval failed");
}
}
