net: Destroy when not readable and not writable

This is only relevant for CentOS 6.3 using kernel version 2.6.32.

On other linuxes and darwin, the `read` call gets an ECONNRESET in that
case.  On sunos, the `write` call fails with EPIPE.

However, old CentOS will occasionally send an EOF instead of a
ECONNRESET or EPIPE when the client has been destroyed abruptly.

Make sure we don't keep trying to write or read more in that case.

Fixes #5504

However, there is still the question of what libuv should do when it
gets an EOF.  Apparently in this case, it will continue trying to read,
which is almost certainly the wrong thing to do.

That should be fixed in libuv, even though this works around the issue.

lib/net.js

@@ -249,9 +249,11 @@ function onSocketEnd() {
   this._readableState.ended = true;
   if (this._readableState.endEmitted) {
     this.readable = false;
+    maybeDestroy(this);
   } else {
     this.once('end', function() {
       this.readable = false;
+      maybeDestroy(this);
     });
     this.read(0);
   }
@@ -399,10 +401,22 @@ Socket.prototype.end = function(data, encoding) {
   // just in case we're waiting for an EOF.
   if (this.readable && !this._readableState.endEmitted)
     this.read(0);
-  return;
+  else
+    maybeDestroy(this);
 };
 
 
+// Call whenever we set writable=false or readable=false
+function maybeDestroy(socket) {
+  if (!socket.readable &&
+      !socket.writable &&
+      !socket.destroyed &&
+      !socket._connecting) {
+    socket.destroy();
+  }
+}
+
+
 Socket.prototype.destroySoon = function() {
   if (this.writable)
     this.end();
@@ -521,8 +535,10 @@ function onread(buffer, offset, length) {
   } else if (process._errno == 'EOF') {
     debug('EOF');
 
-    if (self._readableState.length === 0)
+    if (self._readableState.length === 0) {
       self.readable = false;
+      maybeDestroy(self);
+    }
 
     if (self.onend) self.once('end', self.onend);
 

test/simple/test-net-GH-5504.js

@@ -0,0 +1,123 @@
+// 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.
+
+var common = require('../common');
+var assert = require('assert');
+
+// this test only fails with CentOS 6.3 using kernel version 2.6.32
+// On other linuxes and darwin, the `read` call gets an ECONNRESET in
+// that case.  On sunos, the `write` call fails with EPIPE.
+//
+// However, old CentOS will occasionally send an EOF instead of a
+// ECONNRESET or EPIPE when the client has been destroyed abruptly.
+//
+// Make sure we don't keep trying to write or read more in that case.
+
+switch (process.argv[2]) {
+  case 'server': return server();
+  case 'client': return client();
+  case undefined: return parent();
+  default: throw new Error('wtf');
+}
+
+function server() {
+  var net = require('net');
+  var content = new Buffer(64 * 1024 * 1024);
+  content.fill('#');
+  net.createServer(function(socket) {
+    this.close();
+    socket.on('end', function() {
+      console.error('end');
+    });
+    socket.on('_socketEnd', function() {
+      console.error('_socketEnd');
+    });
+    socket.write(content);
+  }).listen(3000, function() {
+    console.log('listening');
+  });
+}
+
+function client() {
+  var net = require('net');
+  var client = net.connect({
+    host: 'localhost',
+    port: 3000
+  }, function() {
+    client.destroy();
+  });
+}
+
+function parent() {
+  var spawn = require('child_process').spawn;
+  var node = process.execPath;
+  var assert = require('assert');
+  var serverExited = false;
+  var clientExited = false;
+  var serverListened = false;
+  var opt = { env: { NODE_DEBUG: 'net' } };
+
+  process.on('exit', function() {
+    assert(serverExited);
+    assert(clientExited);
+    assert(serverListened);
+    console.log('ok');
+  });
+
+  setTimeout(function() {
+    if (s) s.kill();
+    if (c) c.kill();
+    setTimeout(function() {
+      throw new Error('hang');
+    });
+  }, 1000).unref();
+
+  var s = spawn(node, [__filename, 'server'], opt);
+  var c;
+
+  wrap(s.stderr, process.stderr, 'SERVER 2>');
+  wrap(s.stdout, process.stdout, 'SERVER 1>');
+  s.on('exit', function(c) {
+    console.error('server exited', c);
+    serverExited = true;
+  });
+
+  s.stdout.once('data', function() {
+    serverListened = true;
+    c = spawn(node, [__filename, 'client']);
+    wrap(c.stderr, process.stderr, 'CLIENT 2>');
+    wrap(c.stdout, process.stdout, 'CLIENT 1>');
+    c.on('exit', function(c) {
+      console.error('client exited', c);
+      clientExited = true;
+    });
+  });
+
+  function wrap(inp, out, w) {
+    inp.setEncoding('utf8');
+    inp.on('data', function(c) {
+      c = c.trim();
+      if (!c) return;
+      out.write(w + c.split('\n').join('\n' + w) + '\n');
+    });
+  }
+}
+