wasi,worker: handle termination exception

Be careful when emitting the 'beforeExit' event. It's not allowed to
call into the runtime when a termination exception is pending.

Fixes: #33377

src/api/hooks.cc

@@ -37,11 +37,14 @@ void EmitBeforeExit(Environment* env) {
 
   HandleScope handle_scope(env->isolate());
   Context::Scope context_scope(env->context());
-  Local<Value> exit_code = env->process_object()
-                               ->Get(env->context(), env->exit_code_string())
-                               .ToLocalChecked()
-                               ->ToInteger(env->context())
-                               .ToLocalChecked();
+
+  Local<Value> exit_code_v;
+  if (!env->process_object()->Get(env->context(), env->exit_code_string())
+      .ToLocal(&exit_code_v)) return;
+
+  Local<Integer> exit_code;
+  if (!exit_code_v->ToInteger(env->context()).ToLocal(&exit_code)) return;
+
   ProcessEmit(env, "beforeExit", exit_code).ToLocalChecked();
 }
 

src/node_process_events.cc

@@ -24,10 +24,14 @@ MaybeLocal<Value> ProcessEmit(Environment* env,
                               const char* event,
                               Local<Value> message) {
   // Send message to enable debug in cluster workers
-  Local<Object> process = env->process_object();
   Isolate* isolate = env->isolate();
-  Local<Value> argv[] = {OneByteString(isolate, event), message};
 
+  Local<String> event_string;
+  if (!String::NewFromOneByte(isolate, reinterpret_cast<const uint8_t*>(event))
+      .ToLocal(&event_string)) return MaybeLocal<Value>();
+
+  Local<Object> process = env->process_object();
+  Local<Value> argv[] = {event_string, message};
   return MakeCallback(isolate, process, "emit", arraysize(argv), argv, {0, 0});
 }
 

test/wasi/test-wasi-worker-terminate.js

@@ -0,0 +1,44 @@
+// Flags: --experimental-wasi-unstable-preview1
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const { WASI } = require('wasi');
+const { Worker, parentPort } = require('worker_threads');
+
+// void _start(void) { for (;;); }
+const bytecode = new Uint8Array([
+  0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00, 0x01, 0x04, 0x01, 0x60,
+  0x00, 0x00, 0x03, 0x02, 0x01, 0x00, 0x04, 0x05, 0x01, 0x70, 0x01, 0x01,
+  0x01, 0x05, 0x03, 0x01, 0x00, 0x02, 0x06, 0x08, 0x01, 0x7f, 0x01, 0x41,
+  0x80, 0x88, 0x04, 0x0b, 0x07, 0x13, 0x02, 0x06, 0x6d, 0x65, 0x6d, 0x6f,
+  0x72, 0x79, 0x02, 0x00, 0x06, 0x5f, 0x73, 0x74, 0x61, 0x72, 0x74, 0x00,
+  0x00, 0x0a, 0x09, 0x01, 0x07, 0x00, 0x03, 0x40, 0x0c, 0x00, 0x0b, 0x0b,
+  0x00, 0x10, 0x04, 0x6e, 0x61, 0x6d, 0x65, 0x01, 0x09, 0x01, 0x00, 0x06,
+  0x5f, 0x73, 0x74, 0x61, 0x72, 0x74, 0x00, 0x2f, 0x09, 0x70, 0x72, 0x6f,
+  0x64, 0x75, 0x63, 0x65, 0x72, 0x73, 0x01, 0x0c, 0x70, 0x72, 0x6f, 0x63,
+  0x65, 0x73, 0x73, 0x65, 0x64, 0x2d, 0x62, 0x79, 0x01, 0x05, 0x63, 0x6c,
+  0x61, 0x6e, 0x67, 0x0f, 0x31, 0x30, 0x2e, 0x30, 0x2e, 0x30, 0x2d, 0x34,
+  0x75, 0x62, 0x75, 0x6e, 0x74, 0x75, 0x31
+]);
+
+// Do not use isMainThread so that this test itself can be run inside a Worker.
+if (!process.env.HAS_STARTED_WORKER) {
+  process.env.HAS_STARTED_WORKER = 1;
+  const worker = new Worker(__filename);
+  worker.once('message', (message) => {
+    assert.strictEqual(message, 'start');
+    setTimeout(() => worker.terminate(), common.platformTimeout(50));
+  });
+} else {
+  go();
+}
+
+async function go() {
+  const wasi = new WASI({ returnOnExit: true });
+  const imports = { wasi_snapshot_preview1: wasi.wasiImport };
+  const module = await WebAssembly.compile(bytecode);
+  const instance = await WebAssembly.instantiate(module, imports);
+  parentPort.postMessage('start');
+  wasi.start(instance);
+}