LC

Run Wasm Outside the Browser Using WASI

medium7/7

Add a Wasm JIT Using Your Knowledge from Track 2Next

Language

Compiler

2.0s Limit 256MB

Implementation

Write a C program that documents WASI concepts and shows how a Wasm module imports WASI functions.

Requirements:

Print an introduction to WASI
Explain capability-based security
List key wasi_snapshot_preview1 functions
Show how fd_write is imported by a Wasm module
Explain preopened directories
Mention wasmtime and wasmer runtimes
Print a summary of how the runtime provides imported functions
Include the terms: WASI, capability, wasi_snapshot, runtime

Why This Matters

wasmtime, wasmer, and WasmEdge are real, actively-maintained runtimes that implement wasi_snapshot_preview1 exactly as described here, and this capability-based model — no filesystem or network access without an explicit preopened handle — is what lets Fastly's Compute@Edge and similar platforms run untrusted customer code safely outside a browser. Understanding fd_write as the WASI equivalent of POSIX write(2) is the bridge between sandboxed Wasm and real system programming.

Hints

0 / 3 revealed

Validation Suite

main.c

Workspace 1.0