src/org/sonews/daemon/NNTPDaemon.java
author cli
Sun, 29 Aug 2010 18:17:37 +0200
changeset 37 74139325d305
parent 35 ed84c8bdd87b
permissions -rw-r--r--
Switch intent style to Original K&R / Linux / Kernel.
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/*
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 *   SONEWS News Server
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 *   see AUTHORS for the list of contributors
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 *
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 *   This program is free software: you can redistribute it and/or modify
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 *   it under the terms of the GNU General Public License as published by
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 *   the Free Software Foundation, either version 3 of the License, or
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 *   (at your option) any later version.
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 *
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 *   This program is distributed in the hope that it will be useful,
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 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *   GNU General Public License for more details.
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 *
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 *   You should have received a copy of the GNU General Public License
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 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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package org.sonews.daemon;
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import org.sonews.config.Config;
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import org.sonews.Main;
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import org.sonews.util.Log;
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import java.io.IOException;
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import java.net.BindException;
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import java.net.InetSocketAddress;
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import java.net.ServerSocket;
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import java.nio.channels.CancelledKeyException;
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import java.nio.channels.ClosedChannelException;
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import java.nio.channels.SelectionKey;
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import java.nio.channels.Selector;
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import java.nio.channels.ServerSocketChannel;
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import java.nio.channels.SocketChannel;
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/**
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 * NNTP daemon using SelectableChannels.
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 * @author Christian Lins
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 * @since sonews/0.5.0
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 */
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public final class NNTPDaemon extends AbstractDaemon
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{
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	public static final Object RegisterGate = new Object();
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	private static NNTPDaemon instance = null;
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	public static synchronized NNTPDaemon createInstance(int port)
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	{
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		if (instance == null) {
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			instance = new NNTPDaemon(port);
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			return instance;
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		} else {
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			throw new RuntimeException("NNTPDaemon.createInstance() called twice");
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		}
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	}
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	private int port;
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	private NNTPDaemon(final int port)
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	{
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		Log.get().info("Server listening on port " + port);
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		this.port = port;
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	}
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	@Override
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	public void run()
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	{
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		try {
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			// Create a Selector that handles the SocketChannel multiplexing
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			final Selector readSelector = Selector.open();
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			final Selector writeSelector = Selector.open();
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			// Start working threads
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			final int workerThreads = Runtime.getRuntime().availableProcessors() * 4;
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			ConnectionWorker[] cworkers = new ConnectionWorker[workerThreads];
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			for (int n = 0; n < workerThreads; n++) {
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				cworkers[n] = new ConnectionWorker();
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				cworkers[n].start();
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			}
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			ChannelWriter.getInstance().setSelector(writeSelector);
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			ChannelReader.getInstance().setSelector(readSelector);
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			ChannelWriter.getInstance().start();
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			ChannelReader.getInstance().start();
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			final ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
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			serverSocketChannel.configureBlocking(true);  // Set to blocking mode
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			// Configure ServerSocket; bind to socket...
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			final ServerSocket serverSocket = serverSocketChannel.socket();
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			serverSocket.bind(new InetSocketAddress(this.port));
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			while (isRunning()) {
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				SocketChannel socketChannel;
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				try {
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					// As we set the server socket channel to blocking mode the accept()
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					// method will block.
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					socketChannel = serverSocketChannel.accept();
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					socketChannel.configureBlocking(false);
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					assert socketChannel.isConnected();
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					assert socketChannel.finishConnect();
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				} catch (IOException ex) {
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					// Under heavy load an IOException "Too many open files may
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					// be thrown. It most cases we should slow down the connection
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					// accepting, to give the worker threads some time to process work.
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					Log.get().severe("IOException while accepting connection: " + ex.getMessage());
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					Log.get().info("Connection accepting sleeping for seconds...");
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					Thread.sleep(5000); // 5 seconds
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					continue;
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				}
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				final NNTPConnection conn;
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				try {
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					conn = new NNTPConnection(socketChannel);
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					Connections.getInstance().add(conn);
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				} catch (IOException ex) {
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					Log.get().warning(ex.toString());
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					socketChannel.close();
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					continue;
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				}
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				try {
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					SelectionKey selKeyWrite =
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						registerSelector(writeSelector, socketChannel, SelectionKey.OP_WRITE);
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					registerSelector(readSelector, socketChannel, SelectionKey.OP_READ);
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					Log.get().info("Connected: " + socketChannel.socket().getRemoteSocketAddress());
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					// Set write selection key and send hello to client
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					conn.setWriteSelectionKey(selKeyWrite);
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					conn.println("200 " + Config.inst().get(Config.HOSTNAME, "localhost")
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						+ " " + Main.VERSION + " news server ready - (posting ok).");
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				} catch (CancelledKeyException cke) {
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					Log.get().warning("CancelledKeyException " + cke.getMessage() + " was thrown: "
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						+ socketChannel.socket());
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				} catch (ClosedChannelException cce) {
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					Log.get().warning("ClosedChannelException " + cce.getMessage() + " was thrown: "
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						+ socketChannel.socket());
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				}
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			}
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		} catch (BindException ex) {
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			// Could not bind to socket; this is a fatal problem; so perform shutdown
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			ex.printStackTrace();
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			System.exit(1);
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		} catch (IOException ex) {
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			ex.printStackTrace();
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		} catch (Exception ex) {
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			ex.printStackTrace();
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		}
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	}
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	public static SelectionKey registerSelector(final Selector selector,
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		final SocketChannel channel, final int op)
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		throws CancelledKeyException, ClosedChannelException
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	{
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		// Register the selector at the channel, so that it will be notified
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		// on the socket's events
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		synchronized (RegisterGate) {
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			// Wakeup the currently blocking reader/writer thread; we have locked
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			// the RegisterGate to prevent the awakened thread to block again
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			selector.wakeup();
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			// Lock the selector to prevent the waiting worker threads going into
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			// selector.select() which would block the selector.
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			synchronized (selector) {
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				return channel.register(selector, op, null);
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			}
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		}
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	}
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}