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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.
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bnoordhuis committed Feb 10, 2012
1 parent 3c3e59b commit 21992318b8eaf87037515ed4c95e406047f11d4e
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@@ -945,14 +945,26 @@ Server.prototype._listen2 = function(address, port, addressType, backlog, fd) {
function listen(self, address, port, addressType, backlog, fd) {
if (!cluster) cluster = require('cluster');
- if (cluster.isWorker) {
- cluster._getServer(self, address, port, addressType, fd, function(handle) {
- self._handle = handle;
- self._listen2(address, port, addressType, backlog, fd);
- });
- } else {
+ if (cluster.isMaster) {
self._listen2(address, port, addressType, backlog, fd);
+ return;
}
+
+ cluster._getServer(self, address, port, addressType, fd, function(handle) {
+ // Some operating systems (notably OS X and Solaris) don't report EADDRINUSE
+ // errors right away. libuv mimics that behavior for the sake of platform
+ // consistency but that means we have have a socket on our hands that is
+ // not actually bound. That's why we check if the actual port matches what
+ // we requested and if not, raise an error. The exception is when port == 0
+ // because that means "any random port".
+ if (port && port != handle.getsockname().port) {
+ self.emit('error', errnoException('EADDRINUSE', 'bind'));
+ return;
+ }
+
+ self._handle = handle;
+ self._listen2(address, port, addressType, backlog, fd);
+ });
}
@@ -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 supervisor. As a tree it looks something
+// like this:
+//
+// <supervisor>
+// / \
+// <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.bind(process));
+ process.on('message', worker.send.bind(worker));
+ process.on('SIGTERM', function() {
+ worker.destroy();
+ process.exit();
+ });
+}

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