hidtools.uhid module

class UHIDDevice

Bases: object

A uhid device. uhid is a kernel interface to create virtual HID devices based on a report descriptor.

This class also acts as context manager for any UHIDDevice objects. See dispatch() for details.

uniq

A uniq string assigned to this device. This string is autogenerated and can be used to reliably identify the device.

UHID_FEATURE_REPORT: Final = 0
UHID_INPUT_REPORT: Final = 2
UHID_OUTPUT_REPORT: Final = 1
property bus: BusType | None

The device’s bus type hidtools.util.BusType

call_input_event(_data: Iterable[int]) None

Send an input event from this device.

Parameters:

data (list) – a list of 8-bit integers representing the HID report for this input event

close() None

Called when a userspace client closes the created kernel device.

Sending events on a closed device will not result in anyone reading it.

This message is sent by the kernel, to receive this message you must call dispatch()

create_kernel_device() None

Create a kernel device from this device. Note that the device is not immediately ready to go after creation, you must wait for start() and ideally for open() to be called.

Raises:

UHIDIncompleteException if the device does not have a name, report descriptor or the info bits set.

create_report(data: Any, global_data=None, reportID: int | None = None, application: str | int | None = None) List[int]

Convert the data object to an array of ints representing the report. Each property of the given data object is matched against the field usage name (think hasattr) and filled in accordingly.:

mouse = MouseData()
mouse.b1 = int(l)
mouse.b2 = int(r)
mouse.b3 = int(m)
mouse.x = x
mouse.y = y

data_bytes = uhid_device.create_report(mouse)

The UHIDDevice will create the report according to the device’s report descriptor.

destroy() None

Destroy the device. The kernel will trigger the appropriate messages in response before removing the device.

This function is called automatically on __exit__()

property device_nodes: List[str]

A list of evdev nodes associated with this HID device. Populating this list requires the kernel to process the uhid device, and sometimes the kernel needs to talk to the uhid process. Ensure that dispatch() is called and that you wait for some reasonable time after creating the device.

classmethod dispatch(timeout: float | None = None) bool

Process any events available on any internally registered file descriptor and deal with the events.

The caller must call this function regularly to make sure things like udev events are processed correctly. There’s no indicator of when to call dispatch() yet, call it whenever you’re idle.

Returns:

True if data was processed, False otherwise

property fd: int

The fd to the /dev/uhid device node

get_report(req: int, rnum: int, rtype: int) Tuple[int, List[int]]

Callback invoked when a process calls SetReport on this UHID device.

Return (0, [data bytes]) on success or (errno, []) on failure.

The default method always returns (EIO, []) for a failure. Override this in your device if you want GetReport to succeed.

Parameters:
property hidraw_nodes: List[str]

A list of hidraw nodes associated with this HID device. Populating this list requires the kernel to process the uhid device, and sometimes the kernel needs to talk to the uhid process. Ensure that dispatch() is called and that you wait for some reasonable time after creating the device.

property info: Tuple[int, int, int] | None

The devices’s bus, vendor ID and product ID as tuple

property name: str | None

The devices HID name

open() None

Called when a userspace client opens the created kernel device.

This message is sent by the kernel, to receive this message you must call dispatch()

output_report(data: List[int], size: int, rtype: int) None

Callback invoked when a process sends raw data to the device.

Parameters:
property phys: str | None

The device’s phys string

property pid: int | None

The device’s 16-bit product ID

property rdesc: List[int] | None

The device’s report descriptor

set_report(req: int, rnum: int, rtype: int, data: List[int]) int

Callback invoked when a process calls SetReport on this UHID device.

Return 0 on success or an errno on failure.

The default method always returns EIO for a failure. Override this in your device if you want SetReport to succeed.

Parameters:
start(flags: int) None

Called when the uhid device is ready to accept IO.

This message is sent by the kernel, to receive this message you must call dispatch()

stop() None

Called when the uhid device no longer accepts IO.

This message is sent by the kernel, to receive this message you must call dispatch()

property sys_path: Path | None

The device’s /sys path

property vid: int | None

The device’s 16-bit vendor ID

walk_sysfs(kind: str, glob: str | None = None) Tuple[Path, ...]
exception UHIDIncompleteException

Bases: Exception

An exception raised when a UHIDDevice does not have sufficient information to create a kernel device.