kbd-evdev

Linux evdev backend for kbd — device discovery, hotplug, grab, and event forwarding.

Features

Device discovery — scans /dev/input/ for keyboards (devices supporting A–Z + Enter)
Hotplug — inotify watch for device add/remove at runtime
Exclusive grab — EVIOCGRAB for intercepting events before other applications
Event forwarding — uinput virtual device re-emits unmatched events in grab mode
Key conversion — extension traits for evdev::KeyCode ↔ kbd::Key

Prerequisites

Linux only — uses /dev/input/, inotify, and /dev/uinput

Read access to /dev/input/ — run as root or add your user to the input group:

sudo usermod -aG input $USER
# log out and back in for the group change to take effect

Write access to /dev/uinput (grab mode only) — needed for the virtual device that forwards unmatched events

Usage

[dependencies]
kbd-evdev = "0.1"

Key conversion

use evdev::KeyCode;
use kbd::prelude::*;
use kbd_evdev::{EvdevKeyCodeExt, KbdKeyExt};

// evdev → kbd
let key: Key = KeyCode::KEY_A.to_key();
assert_eq!(key, Key::A);

// kbd → evdev
let code: KeyCode = Key::A.to_key_code();
assert_eq!(code, KeyCode::KEY_A);

Device polling

use std::path::Path;
use kbd_evdev::devices::{DeviceManager, DeviceGrabMode};

let mut manager = DeviceManager::new(
    Path::new("/dev/input"),
    DeviceGrabMode::Shared,
);

// Build pollfd array from manager's file descriptors
let mut pollfds: Vec<libc::pollfd> = manager
    .poll_fds()
    .iter()
    .map(|&fd| libc::pollfd { fd, events: libc::POLLIN, revents: 0 })
    .collect();

// Poll and process events
unsafe { libc::poll(pollfds.as_mut_ptr(), pollfds.len() as _, 100) };
let result = manager.process_polled_events(&pollfds);

for event in &result.key_events {
    println!("{:?} {:?}", event.key, event.transition);
}

Architecture

/dev/input/event*          DeviceManager
  ├─ event0  ──┐       ┌─ discover + poll ──→ DeviceKeyEvent
  ├─ event1  ──┼──────→│  hotplug (inotify)   │
  └─ event2  ──┘       └───────────────────────┘
                                               │
                                     EvdevKeyCodeExt::to_key()
                                               │
                                               ▼
                                          kbd::Key

License

kbd-evdev is licensed under the MIT license. See the LICENSE file for more information.

kbd-evdev 0.1.0