lib: be robust when process global is clobbered

Program bugs sometimes happen to overwrite the `process` global object,
leading to unpredictable runtime errors.  The bug is often hard to track
down because the crash usually looks unrelated and happens far away from
the bug point.

Make core mostly immune to such corruption by ensuring that all core
modules close over a direct reference to the process object instead
of a dynamic reference.

Author: bnoordhuis

lib/internal/bootstrap_node.js

@@ -504,7 +504,7 @@
   };
 
   NativeModule.wrapper = [
-    '(function (exports, require, module, __filename, __dirname) { ',
+    '(function (exports, require, module, __filename, process) { ',
     '\n});'
   ];
 
@@ -520,7 +520,7 @@
         lineOffset: 0,
         displayErrors: true
       });
-      fn(this.exports, NativeModule.require, this, this.filename);
+      fn(this.exports, NativeModule.require, this, this.filename, process);
 
       this.loaded = true;
     } finally {

lib/module.js

@@ -54,8 +54,15 @@ Module._extensions = {};
 var modulePaths = [];
 Module.globalPaths = [];
 
-Module.wrapper = NativeModule.wrapper;
-Module.wrap = NativeModule.wrap;
+Module.wrapper = [
+  '(function (exports, require, module, __filename, __dirname) { ',
+  '\n});'
+];
+
+Module.wrap = function wrap(script) {
+  return Module.wrapper[0] + script + Module.wrapper[1];
+};
+
 Module._debug = util.debuglog('module');
 
 // We use this alias for the preprocessor that filters it out

test/parallel/test-process-clobber.js

@@ -0,0 +1,5 @@
+/* eslint-disable no-global-assign */
+/* eslint-disable required-modules */
+'use strict';
+
+process = null;  // Should not bring down program.