Context Daemon (contextd)

A generic, lightweight Linux daemon that exposes process context (e.g., gaming activity), hardware inventory, and system ambient lighting context via Varlink interfaces.

Purpose

contextd allows userspace applications to:

1. Detect active sessions: Seamlessly identify when a high-performance app or game starts or stops across multiple launchers.
2. Hardware Inventory: List connected peripherals (keyboards, mice, controllers) and check their access permissions (uaccess).
3. IPC Ambient Lighting Bridge: Exposes unprivileged sockets for user-level apps and hardware micro-daemons (like argbd or OpenRGB bridges) to publish and consume ambient lighting vibe contexts.

Workspace Architecture

contextd/
├── src/                            # contextd Core System & RGB Daemon
├── contextd-client/                # Official Rust Client Library (contextd-client)
└── bridges/
    └── openrgb-contextd-bridge/    # Optional OpenRGB SDK TCP Bridge (Port 6742)

Components

• contextd: Core daemon serving game detection, hardware inventory, and RGB observer/control Varlink sockets.
• contextd-client: Official Rust client crate providing type-safe Rust interfaces (ObserverClient, ControlClient) with automatic connection recovery.
• openrgb-contextd-bridge: Optional TCP server bridge on port 6742 that accepts OpenRGB SDK RGB updates and forwards them to contextd.

Features

• Wide Launcher Support: Detects games and apps from Steam (Native/Flatpak), Heroic Games Launcher, and Lutris.
• Hardware-Aware: Groups complex udev nodes into single logical devices; provides main hardware and dedicated RGB inventory.
• System Diagnostics: Reports RAM, CPU, GPU specs, kernel version, and verifies Vulkan and OpenGL libraries.
• Modern IPC: Uses Varlink over Unix sockets (/run/contextd/public/contextd-rgb-observer.socket and /run/contextd/private/contextd-rgb-control.socket).
• systemd Native: Distributed as a systemd portable service (portablectl) for zero-dependency Linux deployment.

Installation & Deployment (systemd portablectl)

Universal Deployment

Run the production deployment script to assemble the portable OS tree in /opt/contextd and manage portablectl attachment:

./scripts/deploy.sh

Optional OpenRGB SDK Bridge Service

To start the optional OpenRGB SDK bridge daemon on TCP port 6742:

sudo systemctl enable --now openrgb-contextd-bridge.service

Interaction

Use the contextctl helper to query the daemon:

# Get active game/app
./scripts/contextctl.sh active

# List installed games
./scripts/contextctl.sh list-games

# List connected gaming peripherals
./scripts/contextctl.sh list-devices

# List RGB controllers, fans, and lights
./scripts/contextctl.sh list-rgb

# Get system diagnostics
./scripts/contextctl.sh diagnostics

Security & Access Control

• Unprivileged Observer Socket: Ambient lighting vibe stream is public via /run/contextd/public/contextd-rgb-observer.socket.
• Restricted Control Socket: Writing lighting state changes is handled via /run/contextd/private/contextd-rgb-control.socket.
• Peer Validation: Uses SO_PEERCRED to identify systemd units for restricted operations.

Development & Verification

Build and run CI tests across the workspace:

cargo fmt -- --check
cargo clippy --all-targets --all-features -- -D warnings
cargo test --workspace

License

MIT