J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.nio.ch; |
| 27 | |
| 28 | import java.lang.reflect.Constructor; |
| 29 | import java.io.FileDescriptor; |
| 30 | import java.io.IOException; |
| 31 | import java.net.InetAddress; |
| 32 | import java.net.InetSocketAddress; |
| 33 | import java.nio.channels.Channel; |
| 34 | import java.nio.channels.SocketChannel; |
| 35 | import java.nio.channels.ServerSocketChannel; |
| 36 | import java.nio.channels.DatagramChannel; |
| 37 | import java.nio.channels.spi.SelectorProvider; |
| 38 | |
| 39 | class InheritedChannel { |
| 40 | |
| 41 | // the "types" of socket returned by soType0 |
| 42 | private static final int UNKNOWN = -1; |
| 43 | private static final int SOCK_STREAM = 1; |
| 44 | private static final int SOCK_DGRAM = 2; |
| 45 | |
| 46 | // oflag values when opening a file |
| 47 | private static final int O_RDONLY = 0; |
| 48 | private static final int O_WRONLY = 1; |
| 49 | private static final int O_RDWR = 2; |
| 50 | |
| 51 | /* |
| 52 | * In order to "detach" the standard streams we dup them to /dev/null. |
| 53 | * In order to reduce the possibility of an error at close time we |
| 54 | * open /dev/null early - that way we know we won't run out of file |
| 55 | * descriptors at close time. This makes the close operation a |
| 56 | * simple dup2 operation for each of the standard streams. |
| 57 | */ |
| 58 | private static int devnull = -1; |
| 59 | |
| 60 | private static void detachIOStreams() { |
| 61 | try { |
| 62 | dup2(devnull, 0); |
| 63 | dup2(devnull, 1); |
| 64 | dup2(devnull, 2); |
| 65 | } catch (IOException ioe) { |
| 66 | // this shouldn't happen |
| 67 | throw new InternalError(); |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * Override the implCloseSelectableChannel for each channel type - this |
| 73 | * allows us to "detach" the standard streams after closing and ensures |
| 74 | * that the underlying socket really closes. |
| 75 | */ |
| 76 | public static class InheritedSocketChannelImpl extends SocketChannelImpl { |
| 77 | |
| 78 | InheritedSocketChannelImpl(SelectorProvider sp, |
| 79 | FileDescriptor fd, |
| 80 | InetSocketAddress remote) |
| 81 | throws IOException |
| 82 | { |
| 83 | super(sp, fd, remote); |
| 84 | } |
| 85 | |
| 86 | protected void implCloseSelectableChannel() throws IOException { |
| 87 | super.implCloseSelectableChannel(); |
| 88 | detachIOStreams(); |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | public static class InheritedServerSocketChannelImpl extends |
| 93 | ServerSocketChannelImpl { |
| 94 | |
| 95 | InheritedServerSocketChannelImpl(SelectorProvider sp, |
| 96 | FileDescriptor fd) |
| 97 | throws IOException |
| 98 | { |
| 99 | super(sp, fd); |
| 100 | } |
| 101 | |
| 102 | protected void implCloseSelectableChannel() throws IOException { |
| 103 | super.implCloseSelectableChannel(); |
| 104 | detachIOStreams(); |
| 105 | } |
| 106 | |
| 107 | } |
| 108 | |
| 109 | public static class InheritedDatagramChannelImpl extends |
| 110 | DatagramChannelImpl { |
| 111 | |
| 112 | InheritedDatagramChannelImpl(SelectorProvider sp, |
| 113 | FileDescriptor fd) |
| 114 | throws IOException |
| 115 | { |
| 116 | super(sp, fd); |
| 117 | } |
| 118 | |
| 119 | protected void implCloseSelectableChannel() throws IOException { |
| 120 | super.implCloseSelectableChannel(); |
| 121 | detachIOStreams(); |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | /* |
| 126 | * If there's a SecurityManager then check for the appropriate |
| 127 | * RuntimePermission. |
| 128 | */ |
| 129 | private static void checkAccess(Channel c) { |
| 130 | SecurityManager sm = System.getSecurityManager(); |
| 131 | if (sm != null) { |
| 132 | sm.checkPermission( |
| 133 | new RuntimePermission("inheritedChannel") |
| 134 | ); |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | |
| 139 | /* |
| 140 | * If standard inherited channel is connected to a socket then return a Channel |
| 141 | * of the appropriate type based standard input. |
| 142 | */ |
| 143 | private static Channel createChannel() throws IOException { |
| 144 | |
| 145 | // dup the file descriptor - we do this so that for two reasons :- |
| 146 | // 1. Avoids any timing issues with FileDescriptor.in being closed |
| 147 | // or redirected while we create the channel. |
| 148 | // 2. Allows streams based on file descriptor 0 to co-exist with |
| 149 | // the channel (closing one doesn't impact the other) |
| 150 | |
| 151 | int fdVal = dup(0); |
| 152 | |
| 153 | // Examine the file descriptor - if it's not a socket then we don't |
| 154 | // create a channel so we release the file descriptor. |
| 155 | |
| 156 | int st; |
| 157 | st = soType0(fdVal); |
| 158 | if (st != SOCK_STREAM && st != SOCK_DGRAM) { |
| 159 | close0(fdVal); |
| 160 | return null; |
| 161 | } |
| 162 | |
| 163 | |
| 164 | // Next we create a FileDescriptor for the dup'ed file descriptor |
| 165 | // Have to use reflection and also make assumption on how FD |
| 166 | // is implemented. |
| 167 | |
| 168 | Class paramTypes[] = { int.class }; |
| 169 | Constructor ctr = Reflect.lookupConstructor("java.io.FileDescriptor", |
| 170 | paramTypes); |
| 171 | Object args[] = { new Integer(fdVal) }; |
| 172 | FileDescriptor fd = (FileDescriptor)Reflect.invoke(ctr, args); |
| 173 | |
| 174 | |
| 175 | // Now create the channel. If the socket is a streams socket then |
| 176 | // we see if tthere is a peer (ie: connected). If so, then we |
| 177 | // create a SocketChannel, otherwise a ServerSocketChannel. |
| 178 | // If the socket is a datagram socket then create a DatagramChannel |
| 179 | |
| 180 | SelectorProvider provider = SelectorProvider.provider(); |
| 181 | assert provider instanceof sun.nio.ch.SelectorProviderImpl; |
| 182 | |
| 183 | Channel c; |
| 184 | if (st == SOCK_STREAM) { |
| 185 | InetAddress ia = peerAddress0(fdVal); |
| 186 | if (ia == null) { |
| 187 | c = new InheritedServerSocketChannelImpl(provider, fd); |
| 188 | } else { |
| 189 | int port = peerPort0(fdVal); |
| 190 | assert port > 0; |
| 191 | InetSocketAddress isa = new InetSocketAddress(ia, port); |
| 192 | c = new InheritedSocketChannelImpl(provider, fd, isa); |
| 193 | } |
| 194 | } else { |
| 195 | c = new InheritedDatagramChannelImpl(provider, fd); |
| 196 | } |
| 197 | return c; |
| 198 | } |
| 199 | |
| 200 | private static boolean haveChannel = false; |
| 201 | private static Channel channel = null; |
| 202 | |
| 203 | /* |
| 204 | * Returns a Channel representing the inherited channel if the |
| 205 | * inherited channel is a stream connected to a network socket. |
| 206 | */ |
| 207 | public static synchronized Channel getChannel() throws IOException { |
| 208 | if (devnull < 0) { |
| 209 | devnull = open0("/dev/null", O_RDWR); |
| 210 | } |
| 211 | |
| 212 | // If we don't have the channel try to create it |
| 213 | if (!haveChannel) { |
| 214 | channel = createChannel(); |
| 215 | haveChannel = true; |
| 216 | } |
| 217 | |
| 218 | // if there is a channel then do the security check before |
| 219 | // returning it. |
| 220 | if (channel != null) { |
| 221 | checkAccess(channel); |
| 222 | } |
| 223 | return channel; |
| 224 | } |
| 225 | |
| 226 | |
| 227 | // -- Native methods -- |
| 228 | |
| 229 | private static native int dup(int fd) throws IOException; |
| 230 | private static native void dup2(int fd, int fd2) throws IOException; |
| 231 | private static native int open0(String path, int oflag) throws IOException; |
| 232 | private static native void close0(int fd) throws IOException; |
| 233 | private static native int soType0(int fd); |
| 234 | private static native InetAddress peerAddress0(int fd); |
| 235 | private static native int peerPort0(int fd); |
| 236 | |
| 237 | static { |
| 238 | Util.load(); |
| 239 | } |
| 240 | } |