bootstrap: make I/O streams work with user-land snapshot

Use the mksnapshot cleanup hooks to release the references to the native streams so that they can be destroyed right before the snapshot is taken, and move the initialization of the global console to pre-execution so that they can be re-initialized during snapshot dehydration. This makes it possible for user-land snapshots to use the I/O during snapshot building.
nodejs · joyeecheung · Jun 11, 2021 · Mar 24, 2022 · Mar 25, 2022 · Mar 24, 2022
commit c812b986554b3146fcfc3b812e9fefc12ecd5a3c
diff --git a/lib/internal/bootstrap/pre_execution.js b/lib/internal/bootstrap/pre_execution.js
@@ -124,6 +124,12 @@ function patchProcessObject(expandArgv1) {
     }
   }
 
+  // We need to initialize the global console here again with process.stdout
+  // and friends for snapshot deserialization.
+  const globalConsole = require('internal/console/global');
+  const { initializeGlobalConsole } = require('internal/console/constructor');
+  initializeGlobalConsole(globalConsole);
+
   // TODO(joyeecheung): most of these should be deprecated and removed,
   // except some that we need to be able to mutate during run time.
   addReadOnlyProcessAlias('_eval', '--eval');

diff --git a/lib/internal/bootstrap/switches/is_main_thread.js b/lib/internal/bootstrap/switches/is_main_thread.js
@@ -122,27 +122,53 @@ let stdin;
 let stdout;
 let stderr;
 
+let stdoutDestroy;
+let stderrDestroy;
+
+function refreshStdoutOnSigWinch() {
+  stdout._refreshSize();
+}
+
+function refreshStderrOnSigWinch() {
+  stderr._refreshSize();
+}
+
 function getStdout() {
   if (stdout) return stdout;
   stdout = createWritableStdioStream(1);
   stdout.destroySoon = stdout.destroy;
   // Override _destroy so that the fd is never actually closed.
+  stdoutDestroy = stdout._destroy;
   stdout._destroy = dummyDestroy;
   if (stdout.isTTY) {
-    process.on('SIGWINCH', () => stdout._refreshSize());
+    process.on('SIGWINCH', refreshStdoutOnSigWinch);
   }
+
+  internalBinding('mksnapshot').cleanups.push(function cleanupStdout() {
+    stdout._destroy = stdoutDestroy;
+    stdout.destroy();
+    process.removeListener('SIGWINCH', refreshStdoutOnSigWinch);
+    stdout = undefined;
+  });
   return stdout;
 }
 
 function getStderr() {
   if (stderr) return stderr;
   stderr = createWritableStdioStream(2);
   stderr.destroySoon = stderr.destroy;
+  stderrDestroy = stderr._destroy;
   // Override _destroy so that the fd is never actually closed.
   stderr._destroy = dummyDestroy;
   if (stderr.isTTY) {
-    process.on('SIGWINCH', () => stderr._refreshSize());
+    process.on('SIGWINCH', refreshStderrOnSigWinch);
   }
+  internalBinding('mksnapshot').cleanups.push(function cleanupStderr() {
+    stderr._destroy = stderrDestroy;
+    stderr.destroy();
+    process.removeListener('SIGWINCH', refreshStderrOnSigWinch);
+    stderr = undefined;
+  });
   return stderr;
 }
 
@@ -229,6 +255,10 @@ function getStdin() {
     }
   }
 
+  internalBinding('mksnapshot').cleanups.push(function cleanupStdin() {
+    stdin.destroy();
+    stdin = undefined;
+  });
   return stdin;
 }
 

diff --git a/lib/internal/console/constructor.js b/lib/internal/console/constructor.js
@@ -669,9 +669,15 @@ Console.prototype.dirxml = Console.prototype.log;
 Console.prototype.error = Console.prototype.warn;
 Console.prototype.groupCollapsed = Console.prototype.group;
 
+function initializeGlobalConsole(globalConsole) {
+  globalConsole[kBindStreamsLazy](process);
+  globalConsole[kBindProperties](true, 'auto');
+}
+
 module.exports = {
   Console,
   kBindStreamsLazy,
   kBindProperties,
+  initializeGlobalConsole,
   formatTime // exported for tests
 };
diff --git a/lib/internal/console/global.js b/lib/internal/console/global.js
@@ -21,9 +21,7 @@ const {
 } = primordials;
 
 const {
-  Console,
-  kBindStreamsLazy,
-  kBindProperties
+  Console
 } = require('internal/console/constructor');
 
 const globalConsole = ObjectCreate({});
@@ -44,9 +42,6 @@ for (const prop of ReflectOwnKeys(Console.prototype)) {
   ReflectDefineProperty(globalConsole, prop, desc);
 }
 
-globalConsole[kBindStreamsLazy](process);
-globalConsole[kBindProperties](true, 'auto');
-
 // This is a legacy feature - the Console constructor is exposed on
 // the global console instance.
 globalConsole.Console = Console;