Supervisor (PID 1)

The supervisor is a 697 KB static Rust binary that serves as PID 1 — the first and only native process in VyomaOS. It manages every aspect of the system above the kernel.

Modules

Manifest Parser

Reads vyoma.toml files at startup and validates capability declarations against the schema. Invalid manifests are rejected with clear error messages.

[app]
name    = "shell"
version = "0.1.0"
wasm    = "shell.wasm"

[capabilities]
stdio      = true
filesystem = true
shell      = true

Concurrent Scheduler

Spawns one thread per WASM app, each running a Wasmtime process. Supports restart policies:

• never: One-shot apps that exit and stay stopped
• always: Apps that restart automatically on exit (e.g., shell, gui-demo)

IPC Broker

Intercepts messages written to stdout by apps and routes them:

• Unicast: @app-name: message — routes to a specific app
• Broadcast: @broadcast: message — delivers to all running apps
• Reply: @reply: message — routes back to the last sender
• Supervisor: @supervisor: command — built-in control commands

Display Driver

Opens /dev/fb0 (DRM/virtio-gpu framebuffer) and renders:

• Parses VYOMA_DRAW: protocol commands from app stdout
• Renders text using a built-in 8x16 bitmap font
• Manages window chrome: title bars, focus borders, status strips
• Tracks per-app flush rate (FPS)
• Supports double-buffered compositing

Input Router

Puts the TTY in raw mode and dispatches input events:

• Keyboard: Per-keypress dispatch to the focused app via VYOMA_INPUT:key: prefix
• Mouse: Click, move, and drag events via VYOMA_INPUT:mouse: prefix
• Hotkeys: Alt+? for shortcut overlay, click-to-focus in menu bar

Process Manager

Runtime process management via console commands and IPC:

Command	Description
ps	List running apps with PID, name, uptime
log <name>	Print app’s captured log output
logf <name>	Tail app logs in real-time
kill <name>	Terminate an app
restart <name>	Restart an app
reload <name>	Reload app from disk

Supervisor IPC Commands

Apps (or the console) can send commands to the supervisor:

Command	Response
@supervisor: list	List of running app names
@supervisor: apps	Running app name list
@supervisor: ping	pong with timestamp
@supervisor: uptime	System uptime since boot
@supervisor: version	VyomaOS version string
@supervisor: focus <name>	Switch keyboard focus to app
@supervisor: loglevel <level>	Set per-app log level filter
@supervisor: kill <name>	Terminate an app

Build

The supervisor compiles as a static musl binary:

cd supervisor
cargo build --target x86_64-unknown-linux-musl --release

Output: supervisor/target/x86_64-unknown-linux-musl/release/supervisor (697 KB)

Code Organization

The supervisor follows a 500-line-per-file rule. Major subsystems are split into focused modules:

• main.rs — Entry point, boot sequence, app spawn loop
• chrome.rs — Window chrome rendering (title bars, borders)
• display/ — Framebuffer driver, compositor
• draw_cmd.rs — VYOMA_DRAW protocol parser
• ipc_handlers.rs — IPC message routing
• ipc_commands/ — Built-in supervisor commands
• input_keys.rs — Keyboard input handling
• mouse_input.rs — Mouse event processing
• app_threads.rs — Per-app thread management
• mount.rs — Filesystem mounting
• net.rs — Network setup
• packages.rs — Package manager
• seccomp.rs — Seccomp BPF setup
• toast.rs — Toast overlay rendering