socket.java

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/*
 * @(#)Socket.java	1.63 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.  
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER  
 *   
 * This program is free software; you can redistribute it and/or  
 * modify it under the terms of the GNU General Public License version  
 * 2 only, as published by the Free Software Foundation.   
 *   
 * This program is distributed in the hope that it will be useful, but  
 * WITHOUT ANY WARRANTY; without even the implied warranty of  
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU  
 * General Public License version 2 for more details (a copy is  
 * included at /legal/license.txt).   
 *   
 * You should have received a copy of the GNU General Public License  
 * version 2 along with this work; if not, write to the Free Software  
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  
 * 02110-1301 USA   
 *   
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa  
 * Clara, CA 95054 or visit www.sun.com if you need additional  
 * information or have any questions. 
 *
 */

package java.net;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.security.AccessController;
import java.security.PrivilegedExceptionAction;

/**
 * This class implements client sockets (also called just
 * "sockets"). A socket is an endpoint for communication
 * between two machines.
 * <p>
 * The actual work of the socket is performed by an instance of the
 * <code>SocketImpl</code> class. An application, by changing
 * the socket factory that creates the socket implementation,
 * can configure itself to create sockets appropriate to the local
 * firewall.
 *
 * @author  unascribed
 * @version 1.56, 08/09/01
 * @see     java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
 * @see     java.net.SocketImpl
 * @since   JDK1.0
 */
public
class Socket {
    /**
     * Various states of this socket.
     */
    private boolean created = false;
    private boolean bound = false;
    private boolean connected = false;
    private boolean closed = false;
    private Object closeLock = new Object();
    private boolean shutIn = false;
    private boolean shutOut = false;

    /**
     * The implementation of this Socket.
     */
    SocketImpl impl;

    /**
     * Are we using an older SocketImpl?
     */
    private boolean oldImpl = false;

    /**
     * Creates an unconnected socket, with the
     * system-default type of SocketImpl.
     *
     * @since   JDK1.1
     * @revised 1.4
     */
    public Socket() {
	setImpl();
    }

    /**
     * Creates an unconnected Socket with a user-specified
     * SocketImpl.
     * <P>
     * @param impl an instance of a <B>SocketImpl</B>
     * the subclass wishes to use on the Socket.
     *
     * @exception SocketException if there is an error in the underlying protocol,     
     * such as a TCP error. 
     * @since   JDK1.1
     */
    protected Socket(SocketImpl impl) throws SocketException {
	this.impl = impl;
	if (impl != null) {
	    checkOldImpl();
	    this.impl.setSocket(this);
	}
    }

    /**
     * Creates a stream socket and connects it to the specified port
     * number on the named host.
     * <p>
     * If the specified host is <tt>null</tt> it is the equivalent of
     * specifying the address as <tt>{@link java.net.InetAddress#getByName InetAddress.getByName}(null)</tt>.
     * In other words, it is equivalent to specifying an address of the 
     * loopback interface. </p>
     * <p>
     * If the application has specified a server socket factory, that
     * factory's <code>createSocketImpl</code> method is called to create
     * the actual socket implementation. Otherwise a "plain" socket is created.
     * <p>
     * If there is a security manager, its
     * <code>checkConnect</code> method is called
     * with the host address and <code>port</code> 
     * as its arguments. This could result in a SecurityException.
     *
     * @param      host   the host name, or <code>null</code> for the loopback address.
     * @param      port   the port number.
     *
     * @exception  UnknownHostException if the IP address of 
     * the host could not be determined.
     *
     * @exception  IOException  if an I/O error occurs when creating the socket.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkConnect</code> method doesn't allow the operation.
     * @see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
     * @see        java.net.SocketImpl
     * @see        java.net.SocketImplFactory#createSocketImpl()
     * @see        SecurityManager#checkConnect
     */
    public Socket(String host, int port)
	throws UnknownHostException, IOException
    {
	this(host != null ? new InetSocketAddress(host, port) :
	     new InetSocketAddress(InetAddress.getByName(null), port),
	     new InetSocketAddress(0), true);
    }

    /**
     * Creates a stream socket and connects it to the specified port
     * number at the specified IP address.
     * <p>
     * If the application has specified a socket factory, that factory's
     * <code>createSocketImpl</code> method is called to create the
     * actual socket implementation. Otherwise a "plain" socket is created.
     * <p>
     * If there is a security manager, its
     * <code>checkConnect</code> method is called
     * with the host address and <code>port</code> 
     * as its arguments. This could result in a SecurityException.
     * 
     * @param      address   the IP address.
     * @param      port      the port number.
     * @exception  IOException  if an I/O error occurs when creating the socket.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkConnect</code> method doesn't allow the operation.
     * @see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
     * @see        java.net.SocketImpl
     * @see        java.net.SocketImplFactory#createSocketImpl()
     * @see        SecurityManager#checkConnect
     */
    public Socket(InetAddress address, int port) throws IOException {
	this(address != null ? new InetSocketAddress(address, port) : null, 
	     new InetSocketAddress(0), true);
    }

    /**
     * Creates a socket and connects it to the specified remote host on
     * the specified remote port. The Socket will also bind() to the local
     * address and port supplied.
     * <p>
     * If the specified host is <tt>null</tt> it is the equivalent of
     * specifying the address as <tt>{@link java.net.InetAddress#getByName InetAddress.getByName}(null)</tt>.
     * In other words, it is equivalent to specifying an address of the 
     * loopback interface. </p>
     * <p>
     * If there is a security manager, its
     * <code>checkConnect</code> method is called
     * with the host address and <code>port</code> 
     * as its arguments. This could result in a SecurityException.
     * 
     * @param host the name of the remote host, or <code>null</code> for the loopback address.
     * @param port the remote port
     * @param localAddr the local address the socket is bound to
     * @param localPort the local port the socket is bound to
     * @exception  IOException  if an I/O error occurs when creating the socket.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkConnect</code> method doesn't allow the operation.
     * @see        SecurityManager#checkConnect
     * @since   JDK1.1
     */
    public Socket(String host, int port, InetAddress localAddr,
		  int localPort) throws IOException {
	this(host != null ? new InetSocketAddress(host, port) :
	       new InetSocketAddress(InetAddress.getByName(null), port),
	     new InetSocketAddress(localAddr, localPort), true);
    }

    /**
     * Creates a socket and connects it to the specified remote address on
     * the specified remote port. The Socket will also bind() to the local
     * address and port supplied.
     * <p>
     * If there is a security manager, its
     * <code>checkConnect</code> method is called
     * with the host address and <code>port</code> 
     * as its arguments. This could result in a SecurityException.
     * 
     * @param address the remote address
     * @param port the remote port
     * @param localAddr the local address the socket is bound to
     * @param localPort the local port the socket is bound to
     * @exception  IOException  if an I/O error occurs when creating the socket.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkConnect</code> method doesn't allow the operation.
     * @see        SecurityManager#checkConnect
     * @since   JDK1.1
     */
    public Socket(InetAddress address, int port, InetAddress localAddr,
		  int localPort) throws IOException {
	this(address != null ? new InetSocketAddress(address, port) : null,
	     new InetSocketAddress(localAddr, localPort), true);
    }

    /**
     * Creates a stream socket and connects it to the specified port
     * number on the named host.
     * <p>
     * If the specified host is <tt>null</tt> it is the equivalent of
     * specifying the address as <tt>{@link java.net.InetAddress#getByName InetAddress.getByName}(null)</tt>.
     * In other words, it is equivalent to specifying an address of the 
     * loopback interface. </p>
     * <p>
     * If the stream argument is <code>true</code>, this creates a
     * stream socket. If the stream argument is <code>false</code>, it
     * creates a datagram socket.
     * <p>
     * If the application has specified a server socket factory, that
     * factory's <code>createSocketImpl</code> method is called to create
     * the actual socket implementation. Otherwise a "plain" socket is created.
     * <p>
     * If there is a security manager, its
     * <code>checkConnect</code> method is called
     * with the host address and <code>port</code> 
     * as its arguments. This could result in a SecurityException.
     * <p>
     * If a UDP socket is used, TCP/IP related socket options will not apply.
     *
     * param      host     the host name.
     * param      port     the port number.
     * param      stream   a <code>boolean</code> indicating whether this is
     *                      a stream socket or a datagram socket.
     * exception  IOException  if an I/O error occurs when creating the socket.
     * exception  SecurityException  if a security manager exists and its  
     *             <code>checkConnect</code> method doesn't allow the operation.
     * see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
     * see        java.net.SocketImpl
     * see        java.net.SocketImplFactory#createSocketImpl()
     * see        SecurityManager#checkConnect
     * deprecated Use DatagramSocket instead for UDP transport.
     *
    public Socket(String host, int port, boolean stream) throws IOException {
	this(host != null ? new InetSocketAddress(host, port) :
	       new InetSocketAddress(InetAddress.getByName(null), port),
	     new InetSocketAddress(0), stream);
    }
     */

    /**
     * Creates a socket and connects it to the specified port number at
     * the specified IP address.
     * <p>
     * If the stream argument is <code>true</code>, this creates a
     * stream socket. If the stream argument is <code>false</code>, it
     * creates a datagram socket.
     * <p>
     * If the application has specified a server socket factory, that
     * factory's <code>createSocketImpl</code> method is called to create
     * the actual socket implementation. Otherwise a "plain" socket is created.
     * 
     * <p>If there is a security manager, its
     * <code>checkConnect</code> method is called
     * with <code>host.getHostAddress()</code> and <code>port</code> 
     * as its arguments. This could result in a SecurityException.
     * <p>
     * If UDP socket is used, TCP/IP related socket options will not apply.
     *
     * param      host     the IP address.
     * param      port      the port number.
     * param      stream    if <code>true</code>, create a stream socket;
     *                       otherwise, create a datagram socket.
     * exception  IOException  if an I/O error occurs when creating the socket.
     * exception  SecurityException  if a security manager exists and its  
     *             <code>checkConnect</code> method doesn't allow the operation.
     * see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
     * see        java.net.SocketImpl
     * see        java.net.SocketImplFactory#createSocketImpl()
     * see        SecurityManager#checkConnect
     * deprecated Use DatagramSocket instead for UDP transport.
     *
    public Socket(InetAddress host, int port, boolean stream) throws IOException {
	this(host != null ? new InetSocketAddress(host, port) : null, 
	     new InetSocketAddress(0), stream);
    }
     */

    private Socket(SocketAddress address, SocketAddress localAddr,
		   boolean stream) throws IOException {
	setImpl();

	// backward compatibility
	if (address == null)
	    throw new NullPointerException();

	try {
	    createImpl(stream);
	    if (localAddr == null)
		localAddr = new InetSocketAddress(0);
	    bind(localAddr);
	    if (address != null)
		connect(address);
	} catch (SocketException e) {
	    close();
	    throw e;
	}
    }

    /**
     * Creates the socket implementation.
     *
     * @param stream a <code>boolean</code> value : <code>true</code> for a TCP socket,
     *		     <code>false</code> for UDP.
     * @throws IOException if creation fails
     * @since 1.4
     */
     void createImpl(boolean stream) throws SocketException {
	if (impl == null) 
	    setImpl();
	try {
	    impl.create(stream);
	    created = true;
	} catch (IOException e) {
	    throw new SocketException(e.getMessage());
	}
    }

    private void checkOldImpl() {
	if (impl == null)
	    return;
	// SocketImpl.connect() is a protected method, therefore we need to use
	// getDeclaredMethod, therefore we need permission to access the member
	try {
	    AccessController.doPrivileged(new PrivilegedExceptionAction() {
		    public Object run() throws NoSuchMethodException {
			Class[] cl = new Class[2];
			cl[0] = SocketAddress.class;
			cl[1] = Integer.TYPE;