child_process: fix handle passing w large payloads

Fix situations in which the handle passed along with a message
that has a large payload and can’t be read entirely by a single
`recvmsg()` call isn’t associated with the message to which it
belongs.

PR-URL: https://github.com/nodejs/node/pull/14588
Fixes: https://github.com/nodejs/node/issues/13778
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/test/parallel/test-cluster-send-handle-large-payload.js b/test/parallel/test-cluster-send-handle-large-payload.js
new file mode 100644
index 0000000000..ba529593e2
--- /dev/null
+++ b/test/parallel/test-cluster-send-handle-large-payload.js
@@ -0,0 +1,40 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cluster = require('cluster');
+const net = require('net');
+
+const payload = 'a'.repeat(800004);
+
+if (cluster.isMaster) {
+  const server = net.createServer();
+
+  server.on('connection', common.mustCall((socket) => socket.unref()));
+
+  const worker = cluster.fork();
+  worker.on('message', common.mustCall(({ payload: received }, handle) => {
+    assert.strictEqual(payload, received);
+    assert(handle instanceof net.Socket);
+    server.close();
+    handle.destroy();
+  }));
+
+  server.listen(0, common.mustCall(() => {
+    const port = server.address().port;
+    const socket = new net.Socket();
+    socket.connect(port, (err) => {
+      assert.ifError(err);
+      worker.send({ payload }, socket);
+    });
+  }));
+} else {
+  process.on('message', common.mustCall(({ payload: received }, handle) => {
+    assert.strictEqual(payload, received);
+    assert(handle instanceof net.Socket);
+    process.send({ payload }, handle);
+
+    // Prepare for a clean exit.
+    process.channel.unref();
+    handle.unref();
+  }));
+}