LidGuard Helper

Privileged helper daemon for LidGuard

Silent background daemon managed by launchd with on-demand socket activation.
Handles features that require elevated privileges or private APIs.

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Features

🛡️ Clamshell Sleep Prevention — sudo pmset disablesleep via sudoers
🔒 Lock Screen Overlay — fullscreen "STOLEN DEVICE" window via SkyLight private API
⚡ Power Button Detection — NSEvent system-defined events (requires Accessibility)

How It Works

LidGuard app ──TCP──▶ launchd ──socket activation──▶ lidguard-helper
                       port 51423                      ├─ pmset
                       JSON + shared secret auth       ├─ SkyLight overlay
                                                       └─ power button monitor

Idle 30s → daemon exits → launchd restarts on next connection

The daemon is not always running. launchd listens on port 51423 and starts the daemon only when the main app connects. Zero resource usage when LidGuard isn't active.

Install

Build from Source

git clone https://github.com/Erel3/lidguard-helper.git
cd lidguard-helper
make build          # Swift release build
make install        # install binary + LaunchAgent, load via launchctl
make uninstall      # unload and remove
make lint           # run swiftlint

Install Location

What	Where
Binary	~/Library/Application Support/LidGuard/lidguard-helper
LaunchAgent	~/Library/LaunchAgents/com.lidguard.helper.plist
Shared secret	~/Library/Application Support/LidGuard/.ipc-secret
Sudoers	/etc/sudoers.d/lidguard (set up by main app or PKG installer)

IPC Protocol

Newline-delimited JSON over localhost TCP port 51423.

Commands (App → Daemon)

Command	Description
auth	Authenticate with shared secret (must be first)
enable_pmset / disable_pmset	Toggle clamshell sleep prevention
show_lock_screen / hide_lock_screen	Toggle lock screen overlay
enable_power_button / disable_power_button	Toggle power button monitoring
get_status	Query current state of all features

Events (Daemon → App)

Event	Description
auth_result	Authentication success/failure
status	Current state of pmset, lock screen, power button
power_button_pressed	Power button was pressed
error	Error message

Permissions

Permission	Why
Accessibility	Power button detection via NSEvent
Sudoers	pmset disablesleep requires root

License

MIT