cluster: propagate bind errors

This commit fixes a bug where the cluster module failed to propagate EADDRINUSE
errors.

When a worker starts a (net, http) server, it requests the listen socket from
its master who then creates and binds the socket.

Now, OS X and Windows don't always signal EADDRINUSE from bind() but instead
defer the error until a later syscall. libuv mimics this behaviour to provide
consistent behaviour across platforms but that means the worker could end up
with a socket that is not actually bound to the requested addresss.

That's why the worker now checks if the socket is bound, raising EADDRINUSE if
that's not the case.

Fixes #2721.

diff --git a/lib/net.js b/lib/net.js
index e41e96a..a797ed6 100644 (file)
--- a/lib/net.js
+++ b/lib/net.js
@@ -756,14 +756,26 @@ Server.prototype._listen2 = function(address, port, addressType) {
 
 
 function listen(self, address, port, addressType) {
-  if (process.env.NODE_WORKER_ID) {
-    require('cluster')._getServer(address, port, addressType, function(handle) {
-      self._handle = handle;
-      self._listen2(address, port, addressType);
-    });
-  } else {
+  if (!process.env.NODE_WORKER_ID) {
     self._listen2(address, port, addressType);
+    return;
   }
+
+  require('cluster')._getServer(address, port, addressType, function(handle) {
+    // OS X doesn't necessarily signal EADDRINUSE from bind(), it may defer
+    // the error until later. libuv mimics this behaviour to provide
+    // consistent behaviour across platforms but that means we could very
+    // well have a socket that is not actually bound... that's why we do
+    // this ghetto port check and raise EADDRINUSE if the requested and the
+    // actual port differ except if port == 0 because that means "any port".
+    if (port && port != handle.getsockname().port) {
+      self.emit('error', errnoException('EADDRINUSE', 'bind'));
+      return;
+    }
+
+    self._handle = handle;
+    self._listen2(address, port, addressType);
+  });
 }
 
 

diff --git a/test/simple/test-cluster-bind-twice.js b/test/simple/test-cluster-bind-twice-v1.js
similarity index 100%
rename from test/simple/test-cluster-bind-twice.js
rename to test/simple/test-cluster-bind-twice-v1.js

diff --git a/test/simple/test-cluster-bind-twice-v2.js b/test/simple/test-cluster-bind-twice-v2.js
new file mode 100644 (file)
index 0000000..1842cce
--- /dev/null
+++ b/test/simple/test-cluster-bind-twice-v2.js
@@ -0,0 +1,115 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// This test starts two clustered HTTP servers on the same port. It expects the
+// first cluster to succeed and the second cluster to fail with EADDRINUSE.
+//
+// The test may seem complex but most of it is plumbing that routes messages
+// from the child processes back to the "super" master. As a tree it looks
+// something like this:
+//
+//         <super master>
+//         /           \
+//     <master 1>   <master 2>
+//       /               \
+//   <worker 1>       <worker 2>
+//
+// The first worker starts a server on a fixed port and fires a ready message
+// that is routed to the second worker. When it tries to bind, it expects to
+// see an EADDRINUSE error.
+//
+// See https://github.com/joyent/node/issues/2721 for more details.
+
+var common = require('../common');
+var assert = require('assert');
+var cluster = require('cluster');
+var fork = require('child_process').fork;
+var http = require('http');
+
+var id = process.argv[2];
+
+if (!id) {
+  var a = fork(__filename, ['one']);
+  var b = fork(__filename, ['two']);
+
+  a.on('message', function(m) {
+    if (typeof m === 'object') return;
+    assert.equal(m, 'READY');
+    b.send('START');
+  });
+
+  var ok = false;
+
+  b.on('message', function(m) {
+    if (typeof m === 'object') return; // ignore system messages
+    assert.equal(m, 'EADDRINUSE');
+    a.kill();
+    b.kill();
+    ok = true;
+  });
+
+  process.on('exit', function() {
+    a.kill();
+    b.kill();
+    assert(ok);
+  });
+}
+else if (id === 'one') {
+  if (cluster.isMaster) return startWorker();
+
+  http.createServer(assert.fail).listen(common.PORT, function() {
+    process.send('READY');
+  });
+}
+else if (id === 'two') {
+  if (cluster.isMaster) return startWorker();
+
+  var ok = false;
+  process.on('SIGTERM', process.exit);
+  process.on('exit', function() {
+    assert(ok);
+  });
+
+  process.on('message', function(m) {
+    if (typeof m === 'object') return; // ignore system messages
+    assert.equal(m, 'START');
+    var server = http.createServer(assert.fail);
+    server.listen(common.PORT, assert.fail);
+    server.on('error', function(e) {
+      assert.equal(e.code, 'EADDRINUSE');
+      process.send(e.code);
+      ok = true;
+    });
+  });
+}
+else {
+  assert(0); // bad command line argument
+}
+
+function startWorker() {
+  var worker = cluster.fork();
+  worker.on('message', process.send);
+  process.on('message', worker.send.bind(worker));
+  process.on('SIGTERM', function() {
+    worker.kill();
+    process.exit();
+  });
+}