vuinputd

Run Sunshine and other uinput-based apps inside containers — with full input isolation and zero kernel patches.

A minimal CUSE-based proxy for /dev/uinput that lets unmodified applications (like Sunshine) run inside containers while creating virtual input devices safely on the host.

Overview

Containerizing input-producing software (e.g. Sunshine, Moonlight host replacements, remote desktop servers) improves separation and simplifies deployment.
However, exposing the host’s /dev/uinput directly into a container breaks isolation:

Containers can create devices visible system-wide or to other containers.
Keyboards and mice may attach to host seats or inject input into active host sessions.

vuinputd exposes a virtual /dev/uinput device inside containers (via CUSE). Input devices created by containerized apps are forwarded to the host kernel’s uinput subsystem, where they appear as normal /dev/input/event* devices visible to all host applications. Those devices are then injected into the containers with udev announcements.

Architecture

vuinputd solves this by introducing a mediated input stack:

A fake /dev/uinput inside each container.
A host proxy daemon that safely creates the actual devices via /dev/uinput.
The proxy forwards add/remove udev events into the container so that wayland compositors that use libinput and other applications see devices natively.
udev rules tag and isolate devices per container, preventing the host from consuming them.

Applications use the /dev/uinput interface unmodified, and the mediation adds negligible overhead.

In principle, this design works with any container runtime — systemd-nspawn, Docker, LXC, Podman, and others.


sequenceDiagram
    box transparent Host
        participant Kernel as uinput (kernel)
        participant Daemon as vuinputd
    end

    box transparent Container
        participant App as Container App
        participant VirtUinput as /dev/uinput (virt)
    end

    Daemon->>VirtUinput: provides virtual /dev/uinput via CUSE
    App->>VirtUinput: creates virtual input device
    VirtUinput->>Daemon: forwards input events
    Daemon->>Kernel: injects events into host uinput
    Kernel->>App: exposes resulting /dev/input/eventX via udev

Benefits

🎮 SDL2 & Wayland compatibility: vuinputd ensures compositors and games recognize input devices correctly.
🔒 Strong isolation: Containers see only their own devices; the host sees them but ignores them completely.
♻️ Safe lifecycle: Devices are removed cleanly when the containerized app stops.
🛠️ Simple integration: No kernel patches required — only userspace tools and udev rules.

Documentation

See docs/BUILD.md for a short build and installation guide.
See docs/DESIGN.md for a detailed overview of the architecture, design trade-offs, and security considerations.

License

MIT

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