Keyboard Locker

A simple, effective utility for Linux to lock your keyboard input while keeping your screen visible and the system running.

Use Cases

• Cat Proofing: Stop your cat from walking across your keyboard and sending unfinished emails, closing windows, or pausing your music.
• Disable Laptop Keyboard: If you are using another keyboard disable the internal laptop one to prevent accidental keypresses.
• Child Safety: Allow your toddler to watch videos or look at photos without worrying about them accidentally deleting files or stopping playback.
• Cleaning: Wipe down your keyboard without needing to shut down your computer or unplug the device.

Features

• System-Level Lock: Uses evdev to grab the keyboard device directly, ensuring input is blocked for all applications.
• Configurable Unlock: Set your own unlock key combination (Default: CTRL + Q).
• Visual Indicator: Clear GUI feedback showing when the keyboard is locked.
• Wayland & X11 Support: Works independently of the display server by interacting with kernel input devices.

Installation

Arch Linux

A PKGBUILD is provided for easy installation on Arch Linux.

makepkg -si

reload the udev rules after install

sudo udevadm control --reload-rules && sudo udevadm trigger --subsystem-match=input --action=change 

If you aren't in the input group add your user

sudo usermod -aG input $USER

Other Linux Distributions (Debian, Ubuntu, Fedora, etc.)

You can build and install the application manually using the provided script.

1. Install Dependencies

You will need the Rust toolchain (cargo) and development libraries for Wayland and OpenGL.

Debian / Ubuntu / Mint:

sudo apt update
sudo apt install build-essential libxkbcommon-dev libwayland-dev libglvnd-dev pkg-config libssl-dev policykit-1
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Fedora / RHEL:

sudo dnf install gcc libxkbcommon-devel wayland-devel libglvnd-devel openssl-devel polkit
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

2. Build and Install

Clone the repository and run the install script:

chmod +x install.sh
./install.sh

This script will compile the application, install it to /usr/local/bin, and install a udev rule to allow running without root.

If you aren't in the input group add your user

sudo usermod -aG input $USER

Usage

1. Open your application menu and launch Keyboard Locker.
2. The application should open immediately (no password required).
3. Once the window opens, you can optionally change the unlock key (Default is Q).
4. Click 🔒 LOCK NOW.
5. Your keyboard is now locked. To unlock, press Left Ctrl + [Your Configured Key] (e.g., Ctrl + Q).

Uninstallation

If you installed via the install.sh script, you can remove the files manually:

sudo rm /usr/local/bin/keyboard-locker
sudo rm /usr/share/pixmaps/keyboard-locker.png
sudo rm /usr/share/applications/keyboard-locker.desktop
sudo rm /etc/udev/rules.d/99-keyboard-locker.rules

Troubleshooting

⚠ No Keyboards Detected

If the application launches but the dropdown is empty or shows a warning, it is likely a permission issue. The application needs direct access to /dev/input/ devices

Fix:

1. Add your user to the input group:

sudo usermod -aG input $USER

2. Reboot your computer.

Note: Simply logging out and back in is often insufficient for device node permissions to update.

🔒 Lock Failed / Device Busy

If you click "LOCK NOW" and it immediately unlocks or shows an error:

• Exclusive Access: Another application may have already "grabbed" the device.
• Device State: The keyboard might have disconnected or changed paths (e.g., KVM switch toggled). Try re-selecting the device from the dropdown.

🔑 Cannot Unlock

If the unlock combination is not working:

1. Ensure you are holding CTRL (Left or Right) while pressing the configured key.
2. The default key is Q (i.e., CTRL + Q).
3. If you customized the key (e.g., to 'X'), use CTRL + X.
4. Emergency Unlock: Unplugging the keyboard will force the application to release the handle. You can then plug it back in to use it normally.

Wayland vs X11

This application uses evdev (kernel-level input drivers). This means it works on Wayland (GNOME, Sway, Hyprland) where traditional X11 screen lockers or input blockers often fail.