1 /* 2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * 26 * 27 * An "echo" service designed to be used with inetd. It can be configured in 28 * inetd.conf to be used by any of the following types of services :- 29 * 30 * stream tcp nowait 31 * stream tcp6 nowait 32 * stream tcp wait 33 * stream tcp6 wait 34 * dgram udp wait 35 * dgram udp6 wait 36 * 37 * If configured as a "tcp nowait" service then inetd will launch a 38 * VM to run the EchoService each time that a client connects to 39 * the TCP port. The EchoService simply echos any messages it 40 * receives from the client and shuts if the client closes the 41 * connection. 42 * 43 * If configured as a "tcp wait" service then inetd will launch a VM 44 * to run the EchoService when a client connects to the port. When 45 * launched the EchoService takes over the listener socket. It 46 * terminates when all clients have disconnected and the service 47 * is idle for a few seconds. 48 * 49 * If configured as a "udp wait" service then a VM will be launched for 50 * each UDP packet to the configured port. System.inheritedChannel() 51 * will return a DatagramChannel. The echo service here will terminate after 52 * echoing the UDP packet back to the client. 53 * 54 * The service closes the inherited network channel when complete. To 55 * facilate testing that the channel is closed the "tcp nowait" service 56 * can close the connection after a given number of bytes. 57 */ 58 import java.io.IOException; 59 import java.net.SocketAddress; 60 import java.nio.ByteBuffer; 61 import java.nio.channels.Channel; 62 import java.nio.channels.DatagramChannel; 63 import java.nio.channels.SelectionKey; 64 import java.nio.channels.Selector; 65 import java.nio.channels.ServerSocketChannel; 66 import java.nio.channels.SocketChannel; 67 68 import jdk.test.lib.Utils; 69 70 public class EchoService { 71 72 private static void doIt(SocketChannel sc, int closeAfter, int delay) throws IOException { 73 ByteBuffer bb = ByteBuffer.allocate(1024); 74 int total = 0; 75 for (;;) { 76 bb.clear(); 77 int n = sc.read(bb); 78 if (n < 0) { 79 break; 80 } 81 total += n; 82 83 // echo 84 bb.flip(); 85 sc.write(bb); 86 87 // close after X bytes? 88 if (closeAfter > 0 && total >= closeAfter) { 89 break; 90 } 91 } 92 93 sc.close(); 94 if (delay > 0) { 95 try { 96 Thread.currentThread().sleep(delay); 97 } catch (InterruptedException x) { } 98 } 99 } 100 101 private static void doIt(DatagramChannel dc) throws IOException { 102 ByteBuffer bb = ByteBuffer.allocate(1024); 103 SocketAddress sa = dc.receive(bb); 104 bb.flip(); 105 dc.send(bb, sa); 106 dc.close(); 107 } 108 109 110 // A worker thread to service a single connection 111 // The class maintains a count of the number of worker threads so 112 // can the service can terminate then all clients disconnect. 113 114 static class Worker implements Runnable { 115 private static int count = 0; 116 private static Object lock = new Object(); 117 118 public static int count() { 119 synchronized (lock) { 120 return count; 121 } 122 } 123 124 private SocketChannel sc; 125 126 Worker(SocketChannel sc) { 127 this.sc = sc; 128 synchronized (lock) { 129 count++; 130 } 131 } 132 133 public void run() { 134 try { 135 doIt(sc, -1, -1); 136 } catch (IOException x) { 137 } finally { 138 synchronized (lock) { 139 count--; 140 } 141 } 142 143 } 144 } 145 146 public static void main(String args[]) throws IOException { 147 Channel c = System.inheritedChannel(); 148 if (c == null) { 149 return; 150 } 151 152 // tcp nowait 153 if (c instanceof SocketChannel) { 154 int closeAfter = 0; 155 int delay = 0; 156 if (args.length > 0) { 157 closeAfter = Integer.parseInt(args[0]); 158 } 159 if (args.length > 1) { 160 delay = Integer.parseInt(args[1]); 161 } 162 doIt((SocketChannel)c, closeAfter, delay); 163 } 164 165 // tcp wait - in this case we take over the listener socket 166 // In this test case we create a thread to service each connection 167 // and terminate after all clients are gone. 168 // 169 if (c instanceof ServerSocketChannel) { 170 ServerSocketChannel ssc = (ServerSocketChannel)c; 171 172 ssc.configureBlocking(false); 173 Selector sel = ssc.provider().openSelector(); 174 SelectionKey sk = ssc.register(sel, SelectionKey.OP_ACCEPT); 175 SocketChannel sc; 176 int count = 0; 177 for (;;) { 178 sel.select((int)Utils.adjustTimeout(5000)); 179 if (sk.isAcceptable() && ((sc = ssc.accept()) != null)) { 180 Worker w = new Worker(sc); 181 (new Thread(w)).start(); 182 } else { 183 // if all clients have disconnected then we die as well. 184 if (Worker.count() == 0) { 185 break; 186 } 187 } 188 } 189 ssc.close(); 190 } 191 192 // udp wait 193 if (c instanceof DatagramChannel) { 194 doIt((DatagramChannel)c); 195 } 196 197 // linger? 198 if (args.length > 0) { 199 int delay = Integer.parseInt(args[0]); 200 try { 201 Thread.currentThread().sleep(delay); 202 } catch (InterruptedException x) { } 203 } 204 205 } 206 207 }