fix(swingset): createVatDynamically option to disable metering

refs #1307

packages/SwingSet/src/kernel/dynamicVat.js

@@ -27,23 +27,37 @@ export function makeDynamicVatCreator(stuff) {
    * defines the vat. This should be generated by calling bundle-source on a
    * module whose default export is makeRootObject(), which takes E as a
    * parameter and returns a root object.
+   * @param options an options bundle. The only option defined so far is
+   * 'metered', which defaults to 'true'. If 'true', the new dynamic vat is
+   * subject to a meter that limits the amount of computation and allocation
+   * that can occur during any given crank. Stack frames are limited as well.
+   * The meter is refilled between cranks, but if the meter ever underflows,
+   * the vat is terminated. If 'false', the vat is unmetered.
    *
    * @return { vatID } the vatID for a newly created vat. The success or
    * failure of the operation will be reported in a message to the admin vat,
    * citing this vatID
    */
 
-  function createVatDynamically(vatSourceBundle) {
-    const vatID = allocateUnusedVatID();
+  function createVatDynamically(vatSourceBundle, options = {}) {
+    const { metered = true, ...unknownOptions } = options;
+    if (Object.keys(unknownOptions).length) {
+      const msg = JSON.stringify(Object.keys(unknownOptions));
+      throw Error(`createVatDynamically got unknown options ${msg}`);
+    }
 
-    // fail-stop: we refill the meter after each crank (in vatManager
-    // doProcess()), but if the vat exhausts its meter within a single crank,
-    // it will never run again. We set refillEachCrank:false because we want
-    // doProcess to do the refilling itself, so it can count the usage
-    const meterRecord = makeGetMeter({
-      refillEachCrank: false,
-      refillIfExhausted: false,
-    });
+    const vatID = allocateUnusedVatID();
+    let meterRecord = null;
+    if (metered) {
+      // fail-stop: we refill the meter after each crank (in vatManager
+      // doProcess()), but if the vat exhausts its meter within a single crank,
+      // it will never run again. We set refillEachCrank:false because we want
+      // doProcess to do the refilling itself, so it can count the usage
+      meterRecord = makeGetMeter({
+        refillEachCrank: false,
+        refillIfExhausted: false,
+      });
+    }
 
     let terminated = false;
 
@@ -80,9 +94,13 @@ export function makeDynamicVatCreator(stuff) {
           `createVatDynamically() requires bundle, not a plain string`,
         );
       }
-      const getMeter = meterRecord.getMeter;
-      const inescapableTransforms = [src => transformMetering(src, getMeter)];
-      const inescapableGlobalLexicals = { getMeter };
+      const inescapableTransforms = [];
+      const inescapableGlobalLexicals = {};
+      if (metered) {
+        const getMeter = meterRecord.getMeter;
+        inescapableTransforms.push(src => transformMetering(src, getMeter));
+        inescapableGlobalLexicals.getMeter = getMeter;
+      }
 
       const vatNS = await importBundle(vatSourceBundle, {
         filePrefix: vatID,

packages/SwingSet/src/kernel/vatAdmin/vatAdmin-src.js

@@ -33,8 +33,8 @@ export default function setup(syscall, state, helpers, endowments) {
       // Called by the wrapper vat to create a new vat. Gets a new ID from the
       // kernel's vat creator fn. Remember that the root object will arrive
       // separately. Clean up the outgoing and incoming arguments.
-      create(bundle) {
-        const vatID = kernelVatCreationFn(bundle);
+      create(bundle, options) {
+        const vatID = kernelVatCreationFn(bundle, options);
         return vatID;
       },
       terminate(_vatID) {

packages/SwingSet/src/kernel/vatAdmin/vatAdminWrapper.js

@@ -21,8 +21,8 @@ export default function setup(syscall, state, helpers) {
 
     function createVatAdminService(vatAdminNode) {
       return harden({
-        createVat(code) {
-          const vatID = D(vatAdminNode).create(code);
+        createVat(code, options) {
+          const vatID = D(vatAdminNode).create(code, options);
 
           const [promise, pendingRR] = producePRR();
           pending.set(vatID, pendingRR);

packages/SwingSet/test/metering/test-unmetered-dynamic-vat.js

@@ -0,0 +1,60 @@
+/* global harden */
+
+import '@agoric/install-metering-and-ses';
+import bundleSource from '@agoric/bundle-source';
+import tap from 'tap';
+import { buildVatController } from '../../src/index';
+import makeNextLog from '../make-nextlog';
+
+function capdata(body, slots = []) {
+  return harden({ body, slots });
+}
+
+function capargs(args, slots = []) {
+  return capdata(JSON.stringify(args), slots);
+}
+
+// Dynamic vats can be created without metering
+
+tap.test('unmetered dynamic vat', async t => {
+  const config = {
+    vats: new Map(),
+    bootstrapIndexJS: require.resolve('./vat-load-dynamic.js'),
+  };
+  const c = await buildVatController(config, []);
+  const nextLog = makeNextLog(c);
+
+  // let the vatAdminService get wired up before we create any new vats
+  await c.run();
+
+  // we'll give this bundle to the loader vat, which will use it to create a
+  // new (unmetered) dynamic vat
+  const dynamicVatBundle = await bundleSource(
+    require.resolve('./metered-dynamic-vat.js'),
+  );
+
+  // 'createVat' will import the bundle
+  c.queueToVatExport(
+    '_bootstrap',
+    'o+0',
+    'createVat',
+    capargs([dynamicVatBundle, { metered: false }]),
+  );
+  await c.run();
+  t.deepEqual(nextLog(), ['created'], 'first create');
+
+  // First, send a message to the dynamic vat that runs normally
+  c.queueToVatExport('_bootstrap', 'o+0', 'run', capargs([]));
+  await c.run();
+
+  t.deepEqual(nextLog(), ['did run'], 'first run ok');
+
+  // Tell the dynamic vat to call `Array(4e9)`. If metering was in place,
+  // this would be rejected. Without metering, it's harmless (Arrays are
+  // lazy).
+  c.queueToVatExport('_bootstrap', 'o+0', 'explode', capargs(['allocate']));
+  await c.run();
+  t.deepEqual(nextLog(), ['failed to explode'], 'metering disabled');
+
+  t.end();
+});

packages/SwingSet/test/metering/vat-load-dynamic.js

@@ -12,8 +12,8 @@ function build(buildStuff) {
       service = await E(vats.vatAdmin).createVatAdminService(devices.vatAdmin);
     },
 
-    async createVat(bundle) {
-      control = await E(service).createVat(bundle);
+    async createVat(bundle, options) {
+      control = await E(service).createVat(bundle, options);
       E(control.adminNode)
         .done()
         .then(