debian/wasi-node

   1 #!/usr/bin/node --experimental-wasi-unstable-preview1
   2 ///
   3 /// Simple WASI executor, adapted from the NodeJS WASI module API docs [1].
   4 ///
   5 /// Usage: wasi-node <command> [<args> .. ]
   6 ///
   7 /// Environment variables:
   8 ///
   9 /// WASI_NODE_PREOPENS - optional JSON file defining the application sandbox
  10 /// directory structure. See [1] for details.
  11 ///
  12 /// WASI_NODE_ENV - optional JSON file defining the application environment.
  13 /// If omitted then the process's POSIX environment is used; this may leak
  14 /// information. If a clean environment is required then set this to /dev/null
  15 /// or some other empty file.
  16 ///
  17 /// [1] https://nodejs.org/api/wasi.html
  18
  19 'use strict';
  20 const fs = require('fs');
  21 const { WASI } = require('wasi');
  22
  23 // argv[0] is nodejs
  24 // argv[1] is this script
  25 var args = process.argv.slice(2); // inner argv includes cmd
  26
  27 if (!args[0]) {
  28   console.warn(process.argv[1] + ": no command given");
  29   process.exit(1);
  30 }
  31
  32 var preopens = {};
  33 var preopens_json = process.env["WASI_NODE_PREOPENS"];
  34 if (preopens_json) {
  35   var preopens_data = fs.readFileSync(preopens_json);
  36   preopens = preopens_data.length ? JSON.parse(preopens_data) : {};
  37 }
  38
  39 var env = process.env;
  40 var env_json = process.env["WASI_NODE_ENV"];
  41 if (env_json) {
  42   var env_data = fs.readFileSync(env_json);
  43   env = env_data.length ? JSON.parse(env_data) : {};
  44 }
  45
  46 const wasi = new WASI({ args: args, env: env, preopens: preopens });
  47 const importObject = { wasi_snapshot_preview1: wasi.wasiImport };
  48
  49 (async () => {
  50   const wasm = await WebAssembly.compile(fs.readFileSync(args[0]));
  51   const instance = await WebAssembly.instantiate(wasm, importObject);
  52
  53   wasi.start(instance);
  54 })();