WASI

Jan 1, 0001

Definition

WASI (WebAssembly System Interface) is a modular system interface designed to provide WebAssembly applications with a consistent and secure way to perform system-level operations, such as file and network access, across different environments. It aims to enable WebAssembly to run outside the browser, providing a sandboxed execution environment that abstracts away platform-specific details, thus enhancing portability and security.

Secure Settings Example

use wasi_common::WasiCtxBuilder;
use wasmtime::{Config, Engine, Store, Module, Instance};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Configure the engine with WASI support
    let mut config = Config::new();
    config.wasi(true);

    // Create a new engine and store
    let engine = Engine::new(&config)?;
    let mut store = Store::new(&engine, WasiCtxBuilder::new().build());

    // Load and instantiate a WASI module
    let module = Module::from_file(&engine, "example.wasm")?;
    let instance = Instance::new(&mut store, &module, &[])?;

    // Execute the module's main function
    let main = instance.get_typed_func::<(), ()>(&mut store, "_start")?;
    main.call(&mut store, ())?;

    Ok(())
}

Insecure Settings Example

use wasmtime::{Config, Engine, Store, Module, Instance};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Incorrectly configured engine without WASI support
    let config = Config::new(); // Missing config.wasi(true)

    // Create a new engine and store
    let engine = Engine::new(&config)?;
    let store = Store::new(&engine, ());

    // Load and instantiate a WASI module
    let module = Module::from_file(&engine, "example.wasm")?;
    let instance = Instance::new(&store, &module, &[])?;

    // Execute the module's main function
    let main = instance.get_typed_func::<(), ()>(&store, "_start")?;
    main.call(&store, ())?;

    Ok(())
}