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242 lines
8.3 KiB
Java
242 lines
8.3 KiB
Java
/*
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* Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.nio.ch;
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import java.lang.reflect.Constructor;
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import java.io.FileDescriptor;
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import java.io.IOException;
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import java.net.InetAddress;
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import java.net.InetSocketAddress;
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import java.nio.channels.Channel;
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import java.nio.channels.SocketChannel;
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import java.nio.channels.ServerSocketChannel;
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import java.nio.channels.DatagramChannel;
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import java.nio.channels.spi.SelectorProvider;
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class InheritedChannel {
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// the "types" of socket returned by soType0
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private static final int UNKNOWN = -1;
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private static final int SOCK_STREAM = 1;
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private static final int SOCK_DGRAM = 2;
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// oflag values when opening a file
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private static final int O_RDONLY = 0;
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private static final int O_WRONLY = 1;
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private static final int O_RDWR = 2;
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/*
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* In order to "detach" the standard streams we dup them to /dev/null.
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* In order to reduce the possibility of an error at close time we
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* open /dev/null early - that way we know we won't run out of file
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* descriptors at close time. This makes the close operation a
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* simple dup2 operation for each of the standard streams.
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*/
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private static int devnull = -1;
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private static void detachIOStreams() {
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try {
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dup2(devnull, 0);
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dup2(devnull, 1);
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dup2(devnull, 2);
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} catch (IOException ioe) {
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// this shouldn't happen
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throw new InternalError(ioe);
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}
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}
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/*
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* Override the implCloseSelectableChannel for each channel type - this
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* allows us to "detach" the standard streams after closing and ensures
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* that the underlying socket really closes.
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*/
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public static class InheritedSocketChannelImpl extends SocketChannelImpl {
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InheritedSocketChannelImpl(SelectorProvider sp,
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FileDescriptor fd,
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InetSocketAddress remote)
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throws IOException
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{
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super(sp, fd, remote);
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}
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protected void implCloseSelectableChannel() throws IOException {
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super.implCloseSelectableChannel();
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detachIOStreams();
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}
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}
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public static class InheritedServerSocketChannelImpl extends
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ServerSocketChannelImpl {
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InheritedServerSocketChannelImpl(SelectorProvider sp,
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FileDescriptor fd)
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throws IOException
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{
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super(sp, fd, true);
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}
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protected void implCloseSelectableChannel() throws IOException {
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super.implCloseSelectableChannel();
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detachIOStreams();
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}
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}
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public static class InheritedDatagramChannelImpl extends
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DatagramChannelImpl {
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InheritedDatagramChannelImpl(SelectorProvider sp,
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FileDescriptor fd)
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throws IOException
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{
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super(sp, fd);
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}
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protected void implCloseSelectableChannel() throws IOException {
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super.implCloseSelectableChannel();
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detachIOStreams();
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}
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}
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/*
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* If there's a SecurityManager then check for the appropriate
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* RuntimePermission.
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*/
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private static void checkAccess(Channel c) {
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SecurityManager sm = System.getSecurityManager();
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if (sm != null) {
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sm.checkPermission(
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new RuntimePermission("inheritedChannel")
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);
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}
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}
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/*
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* If standard inherited channel is connected to a socket then return a Channel
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* of the appropriate type based standard input.
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*/
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private static Channel createChannel() throws IOException {
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// dup the file descriptor - we do this so that for two reasons :-
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// 1. Avoids any timing issues with FileDescriptor.in being closed
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// or redirected while we create the channel.
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// 2. Allows streams based on file descriptor 0 to co-exist with
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// the channel (closing one doesn't impact the other)
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int fdVal = dup(0);
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// Examine the file descriptor - if it's not a socket then we don't
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// create a channel so we release the file descriptor.
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int st;
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st = soType0(fdVal);
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if (st != SOCK_STREAM && st != SOCK_DGRAM) {
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close0(fdVal);
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return null;
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}
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// Next we create a FileDescriptor for the dup'ed file descriptor
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// Have to use reflection and also make assumption on how FD
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// is implemented.
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Class<?> paramTypes[] = { int.class };
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Constructor<?> ctr = Reflect.lookupConstructor("java.io.FileDescriptor",
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paramTypes);
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Object args[] = { Integer.valueOf(fdVal) };
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FileDescriptor fd = (FileDescriptor)Reflect.invoke(ctr, args);
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// Now create the channel. If the socket is a streams socket then
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// we see if tthere is a peer (ie: connected). If so, then we
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// create a SocketChannel, otherwise a ServerSocketChannel.
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// If the socket is a datagram socket then create a DatagramChannel
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SelectorProvider provider = SelectorProvider.provider();
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assert provider instanceof sun.nio.ch.SelectorProviderImpl;
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Channel c;
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if (st == SOCK_STREAM) {
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InetAddress ia = peerAddress0(fdVal);
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if (ia == null) {
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c = new InheritedServerSocketChannelImpl(provider, fd);
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} else {
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int port = peerPort0(fdVal);
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assert port > 0;
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InetSocketAddress isa = new InetSocketAddress(ia, port);
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c = new InheritedSocketChannelImpl(provider, fd, isa);
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}
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} else {
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c = new InheritedDatagramChannelImpl(provider, fd);
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}
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return c;
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}
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private static boolean haveChannel = false;
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private static Channel channel = null;
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/*
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* Returns a Channel representing the inherited channel if the
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* inherited channel is a stream connected to a network socket.
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*/
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public static synchronized Channel getChannel() throws IOException {
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if (devnull < 0) {
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devnull = open0("/dev/null", O_RDWR);
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}
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// If we don't have the channel try to create it
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if (!haveChannel) {
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channel = createChannel();
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haveChannel = true;
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}
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// if there is a channel then do the security check before
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// returning it.
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if (channel != null) {
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checkAccess(channel);
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}
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return channel;
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}
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// -- Native methods --
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private static native void initIDs();
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private static native int dup(int fd) throws IOException;
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private static native void dup2(int fd, int fd2) throws IOException;
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private static native int open0(String path, int oflag) throws IOException;
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private static native void close0(int fd) throws IOException;
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private static native int soType0(int fd);
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private static native InetAddress peerAddress0(int fd);
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private static native int peerPort0(int fd);
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static {
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IOUtil.load();
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initIDs();
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}
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}
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