USB-WASM

Prototype design and implementation of an interface for accessing and communicating with USB devices from a WebAssembly Component. This project forms part of my Master's thesis.

Repository structure

• ./wit/ contains the interface definition in the WIT IDL.
• ./usb-wasm contains the host implementation of the interface for Wasmtime.
• ./usb-wasm-bindings contains the automatically generated Rust bindings. This crate is used in the example/test command components.
• ./command-components contains a couple of command components implemented using the interface.
• ./wasmtime-usb implements a Component Model-enabled Wasmtime CLI application to run command components that use the interface.

Requirements

• Rust
• wasm-tools
• just (optional, to run the commands in the Justfile)

Running the command components

Because Rust can only target WASI preview 1 right now, the compiled WASM binaries first need to be transformed into command components before they can be run by the Component Model-enabled Wasmtime CLI.

wasm-tools is used to 'adapt' the WASM binaries compiled by rustc into command components.

For example, to run the lsusb command component, the following commands have to be executed:

> cargo build -p lsusb --target=wasm32-wasi 
> wasm-tools component new ./target/wasm32-wasi/debug/lsusb.wasm --adapt ./command-components/wasi_snapshot_preview1.command.wasm -o out/lsusb.wasm
> cargo run -- ./out/lsusb.wasm

If you have the just command runner installed, you can just run just lsusb, which will perform all these steps for you.