src: use option parser for expose_internals

bootstrap_node.js was directly parsing process.execArgv to see if
internals should be exposed, even though the argv was already parsed by
node. This is unusual and unnecessary, change it to set the option value
from the parser onto the config binding.

PR-URL: nodejs#12245
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/internal/bootstrap_node.js

@@ -443,11 +443,9 @@
     return NativeModule._source.hasOwnProperty(id);
   };
 
-  const EXPOSE_INTERNALS = process.execArgv.some(function(arg) {
-    return arg.match(/^--expose[-_]internals$/);
-  });
+  const config = process.binding('config');
 
-  if (EXPOSE_INTERNALS) {
+  if (config.exposeInternals) {
     NativeModule.nonInternalExists = NativeModule.exists;
 
     NativeModule.isInternal = function(id) {

src/node.cc

@@ -199,6 +199,12 @@ bool trace_warnings = false;
 // that is used by lib/module.js
 bool config_preserve_symlinks = false;
 
+// Set in node.cc by ParseArgs when --expose-internals or --expose_internals is
+// used.
+// Used in node_config.cc to set a constant on process.binding('config')
+// that is used by lib/internal/bootstrap_node.js
+bool config_expose_internals = false;
+
 // process-relative uptime base, initialized at start-up
 static double prog_start_time;
 static bool debugger_running;
@@ -3896,7 +3902,7 @@ static void ParseArgs(int* argc,
 #endif
     } else if (strcmp(arg, "--expose-internals") == 0 ||
                strcmp(arg, "--expose_internals") == 0) {
-      // consumed in js
+      config_expose_internals = true;
     } else if (strcmp(arg, "--") == 0) {
       index += 1;
       break;

src/node_config.cc

@@ -44,6 +44,9 @@ void InitConfig(Local<Object> target,
 
   if (config_preserve_symlinks)
     READONLY_BOOLEAN_PROPERTY("preserveSymlinks");
+
+  if (config_expose_internals)
+    READONLY_BOOLEAN_PROPERTY("exposeInternals");
 }  // InitConfig
 
 }  // namespace node

src/node_internals.h

@@ -43,6 +43,12 @@ extern std::string openssl_config;
 // that is used by lib/module.js
 extern bool config_preserve_symlinks;
 
+// Set in node.cc by ParseArgs when --expose-internals or --expose_internals is
+// used.
+// Used in node_config.cc to set a constant on process.binding('config')
+// that is used by lib/internal/bootstrap_node.js
+extern bool config_expose_internals;
+
 // Forward declaration
 class Environment;
 

test/parallel/test-internal-modules-expose.js

@@ -3,5 +3,9 @@
 
 require('../common');
 const assert = require('assert');
+const config = process.binding('config');
+
+console.log(config, process.argv);
 
 assert.strictEqual(typeof require('internal/freelist').FreeList, 'function');
+assert.strictEqual(config.exposeInternals, true);