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 * Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 in the LICENSE file that

 * accompanied this code).

 *

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.nio.ch;

import java.io.FileDescriptor;

import java.io.IOException;

import java.net.*;

import java.nio.channels.*;

import java.nio.channels.spi.*;

import java.util.*;

import sun.net.NetHooks;

/**

 * An implementation of ServerSocketChannels

 */

class ServerSocketChannelImpl

    extends ServerSocketChannel

    implements SelChImpl

{

    // Used to make native close and configure calls

    private static NativeDispatcher nd;

    // Our file descriptor

    private final FileDescriptor fd;

    // fd value needed for dev/poll. This value will remain valid

    // even after the value in the file descriptor object has been set to -1

    private int fdVal;

    // ID of native thread currently blocked in this channel, for signalling

    private volatile long thread;

    // Lock held by thread currently blocked in this channel

    private final Object lock = new Object();

    // Lock held by any thread that modifies the state fields declared below

    // DO NOT invoke a blocking I/O operation while holding this lock!

    private final Object stateLock = new Object();

    // -- The following fields are protected by stateLock

    // Channel state, increases monotonically

    private static final int ST_UNINITIALIZED = -1;

    private static final int ST_INUSE = 0;

    private static final int ST_KILLED = 1;

    private int state = ST_UNINITIALIZED;

    // Binding

    private InetSocketAddress localAddress; // null => unbound

    // set true when exclusive binding is on and SO_REUSEADDR is emulated

    private boolean isReuseAddress;

    // Our socket adaptor, if any

    ServerSocket socket;

    // -- End of fields protected by stateLock

    ServerSocketChannelImpl(SelectorProvider sp) throws IOException {

        super(sp);

        this.fd =  Net.serverSocket(true);

        this.fdVal = IOUtil.fdVal(fd);

        this.state = ST_INUSE;

    }

    ServerSocketChannelImpl(SelectorProvider sp,

                            FileDescriptor fd,

                            boolean bound)

        throws IOException

    {

        super(sp);

        this.fd =  fd;

        this.fdVal = IOUtil.fdVal(fd);

        this.state = ST_INUSE;

        if (bound)

            localAddress = Net.localAddress(fd);

    }

    public ServerSocket socket() {

        synchronized (stateLock) {

            if (socket == null)

                socket = ServerSocketAdaptor.create(this);

            return socket;

        }

    }

    @Override

    public SocketAddress getLocalAddress() throws IOException {

        synchronized (stateLock) {

            if (!isOpen())

                throw new ClosedChannelException();

            return localAddress == null ? localAddress

                    : Net.getRevealedLocalAddress(

                          Net.asInetSocketAddress(localAddress));

        }

    }

    @Override

    public <T> ServerSocketChannel setOption(SocketOption<T> name, T value)

        throws IOException

    {

        if (name == null)

            throw new NullPointerException();

        if (!supportedOptions().contains(name))

            throw new UnsupportedOperationException("'" + name + "' not supported");

        synchronized (stateLock) {

            if (!isOpen())

                throw new ClosedChannelException();

            if (name == StandardSocketOptions.IP_TOS) {

                ProtocolFamily family = Net.isIPv6Available() ?

                    StandardProtocolFamily.INET6 : StandardProtocolFamily.INET;

                Net.setSocketOption(fd, family, name, value);

                return this;

            }

            if (name == StandardSocketOptions.SO_REUSEADDR &&

                    Net.useExclusiveBind())

            {

                // SO_REUSEADDR emulated when using exclusive bind

                isReuseAddress = (Boolean)value;

            } else {

                // no options that require special handling

                Net.setSocketOption(fd, Net.UNSPEC, name, value);

            }

            return this;

        }

    }

    @Override

    @SuppressWarnings("unchecked")

    public <T> T getOption(SocketOption<T> name)

        throws IOException

    {

        if (name == null)

            throw new NullPointerException();

        if (!supportedOptions().contains(name))

            throw new UnsupportedOperationException("'" + name + "' not supported");

        synchronized (stateLock) {

            if (!isOpen())

                throw new ClosedChannelException();

            if (name == StandardSocketOptions.SO_REUSEADDR &&

                    Net.useExclusiveBind())

            {

                // SO_REUSEADDR emulated when using exclusive bind

                return (T)Boolean.valueOf(isReuseAddress);

            }

            // no options that require special handling

            return (T) Net.getSocketOption(fd, Net.UNSPEC, name);

        }

    }

    private static class DefaultOptionsHolder {

        static final Set<SocketOption<?>> defaultOptions = defaultOptions();

        private static Set<SocketOption<?>> defaultOptions() {

            HashSet<SocketOption<?>> set = new HashSet<>(2);

            set.add(StandardSocketOptions.SO_RCVBUF);

            set.add(StandardSocketOptions.SO_REUSEADDR);

            if (Net.isReusePortAvailable()) {

                set.add(StandardSocketOptions.SO_REUSEPORT);

            }

            set.add(StandardSocketOptions.IP_TOS);

            return Collections.unmodifiableSet(set);

        }

    }

    @Override

    public final Set<SocketOption<?>> supportedOptions() {

        return DefaultOptionsHolder.defaultOptions;

    }

    public boolean isBound() {

        synchronized (stateLock) {

            return localAddress != null;

        }

    }

    public InetSocketAddress localAddress() {

        synchronized (stateLock) {

            return localAddress;

        }

    }

    @Override

    public ServerSocketChannel bind(SocketAddress local, int backlog) throws IOException {

        synchronized (lock) {

            if (!isOpen())

                throw new ClosedChannelException();

            if (isBound())

                throw new AlreadyBoundException();

            InetSocketAddress isa = (local == null) ? new InetSocketAddress(0) :

                Net.checkAddress(local);

            SecurityManager sm = System.getSecurityManager();

            if (sm != null)

                sm.checkListen(isa.getPort());

            NetHooks.beforeTcpBind(fd, isa.getAddress(), isa.getPort());

            Net.bind(fd, isa.getAddress(), isa.getPort());

            Net.listen(fd, backlog < 1 ? 50 : backlog);

            synchronized (stateLock) {

                localAddress = Net.localAddress(fd);

            }

        }

        return this;

    }

    public SocketChannel accept() throws IOException {

        synchronized (lock) {

            if (!isOpen())

                throw new ClosedChannelException();

            if (!isBound())

                throw new NotYetBoundException();

            SocketChannel sc = null;

            int n = 0;

            FileDescriptor newfd = new FileDescriptor();

            InetSocketAddress[] isaa = new InetSocketAddress[1];

            try {

                begin();

                if (!isOpen())

                    return null;

                thread = NativeThread.current();

                for (;;) {

                    n = accept(this.fd, newfd, isaa);

                    if ((n == IOStatus.INTERRUPTED) && isOpen())

                        continue;

                    break;

                }

            } finally {

                thread = 0;

                end(n > 0);

                assert IOStatus.check(n);

            }

            if (n < 1)

                return null;

            IOUtil.configureBlocking(newfd, true);

            InetSocketAddress isa = isaa[0];

            sc = new SocketChannelImpl(provider(), newfd, isa);

            SecurityManager sm = System.getSecurityManager();

            if (sm != null) {

                try {

                    sm.checkAccept(isa.getAddress().getHostAddress(),

                                   isa.getPort());

                } catch (SecurityException x) {

                    sc.close();

                    throw x;

                }

            }

            return sc;

        }

    }

    protected void implConfigureBlocking(boolean block) throws IOException {

        IOUtil.configureBlocking(fd, block);

    }

    protected void implCloseSelectableChannel() throws IOException {

        synchronized (stateLock) {

            if (state != ST_KILLED)

                nd.preClose(fd);

            long th = thread;

            if (th != 0)

                NativeThread.signal(th);

            if (!isRegistered())

                kill();

        }

    }

    public void kill() throws IOException {

        synchronized (stateLock) {

            if (state == ST_KILLED)

                return;

            if (state == ST_UNINITIALIZED) {

                state = ST_KILLED;

                return;

            }

            assert !isOpen() && !isRegistered();

            nd.close(fd);

            state = ST_KILLED;

        }

    }

    /**

     * Translates native poll revent set into a ready operation set

     */

    public boolean translateReadyOps(int ops, int initialOps,

                                     SelectionKeyImpl sk) {

        int intOps = sk.nioInterestOps(); // Do this just once, it synchronizes

        int oldOps = sk.nioReadyOps();

        int newOps = initialOps;

        if ((ops & Net.POLLNVAL) != 0) {

            // This should only happen if this channel is pre-closed while a

            // selection operation is in progress

            // ## Throw an error if this channel has not been pre-closed

            return false;

        }

        if ((ops & (Net.POLLERR | Net.POLLHUP)) != 0) {

            newOps = intOps;

            sk.nioReadyOps(newOps);

            return (newOps & ~oldOps) != 0;

        }

        if (((ops & Net.POLLIN) != 0) &&

            ((intOps & SelectionKey.OP_ACCEPT) != 0))

                newOps |= SelectionKey.OP_ACCEPT;

        sk.nioReadyOps(newOps);

        return (newOps & ~oldOps) != 0;

    }

    public boolean translateAndUpdateReadyOps(int ops, SelectionKeyImpl sk) {

        return translateReadyOps(ops, sk.nioReadyOps(), sk);

    }

    public boolean translateAndSetReadyOps(int ops, SelectionKeyImpl sk) {

        return translateReadyOps(ops, 0, sk);

    }

    // package-private

    int poll(int events, long timeout) throws IOException {

        assert Thread.holdsLock(blockingLock()) && !isBlocking();

        synchronized (lock) {

            int n = 0;

            try {

                begin();

                synchronized (stateLock) {

                    if (!isOpen())

                        return 0;

                    thread = NativeThread.current();

                }

                n = Net.poll(fd, events, timeout);

            } finally {

                thread = 0;

                end(n > 0);

            }

            return n;

        }

    }

    /**

     * Translates an interest operation set into a native poll event set

     */

    public void translateAndSetInterestOps(int ops, SelectionKeyImpl sk) {

        int newOps = 0;

        // Translate ops

        if ((ops & SelectionKey.OP_ACCEPT) != 0)

            newOps |= Net.POLLIN;

        // Place ops into pollfd array

        sk.selector.putEventOps(sk, newOps);

    }

    public FileDescriptor getFD() {

        return fd;

    }

    public int getFDVal() {

        return fdVal;

    }

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append(this.getClass().getName());

        sb.append('[');

        if (!isOpen()) {

            sb.append("closed");

        } else {

            synchronized (stateLock) {

                InetSocketAddress addr = localAddress();

                if (addr == null) {

                    sb.append("unbound");

                } else {

                    sb.append(Net.getRevealedLocalAddressAsString(addr));

                }

            }

        }

        sb.append(']');

        return sb.toString();

    }

    /**

     * Accept a connection on a socket.

     *

     * @implNote Wrap native call to allow instrumentation.

     */

    private int accept(FileDescriptor ssfd, FileDescriptor newfd,

                       InetSocketAddress[] isaa)

        throws IOException

    {

        return accept0(ssfd, newfd, isaa);

    }

    // -- Native methods --

    // Accepts a new connection, setting the given file descriptor to refer to

    // the new socket and setting isaa[0] to the socket's remote address.

    // Returns 1 on success, or IOStatus.UNAVAILABLE (if non-blocking and no

    // connections are pending) or IOStatus.INTERRUPTED.

    //

    private native int accept0(FileDescriptor ssfd, FileDescriptor newfd,

                               InetSocketAddress[] isaa)

        throws IOException;

    private static native void initIDs();

    static {

        IOUtil.load();

        initIDs();

        nd = new SocketDispatcher();

    }

}