1 /*
   2  * Copyright (c) 2003, 2017, 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  * A collection of utility methods used by the SelectorProvider.inheritedChannel
  26  * unit tests.
  27  */
  28 import java.io.File;
  29 import java.io.FileDescriptor;
  30 import java.lang.reflect.Field;
  31 import java.nio.channels.DatagramChannel;
  32 import java.nio.channels.ServerSocketChannel;
  33 import java.nio.channels.SocketChannel;
  34 
  35 public class Util {
  36 
  37     private static Object get(String className, String fieldName, Object o) throws Exception {
  38         Class cl = Class.forName(className);
  39         Field fld = cl.getDeclaredField(fieldName);
  40         fld.setAccessible(true);
  41         return fld.get(o);
  42     }
  43 
  44     private static int fdVal(FileDescriptor fdObj) throws Exception {
  45         Object fdVal = get("java.io.FileDescriptor", "fd", fdObj);
  46         return ((Integer)fdVal).intValue();
  47     }
  48 
  49     /*
  50      * Return the file descriptor underlying a given SocketChannel
  51      */
  52     public static int getFD(SocketChannel sc) {
  53         try {
  54             Object fdObj = get("sun.nio.ch.SocketChannelImpl", "fd", sc);
  55             return fdVal((FileDescriptor)fdObj);
  56         } catch (Exception x) {
  57             x.printStackTrace();
  58             throw new InternalError(x.getMessage());
  59         }
  60     }
  61 
  62     /*
  63      * Return the file descriptor underlying a given ServerSocketChannel
  64      */
  65     public static int getFD(ServerSocketChannel ssc) {
  66         try {
  67             Object fdObj = get("sun.nio.ch.ServerSocketChannelImpl", "fd", ssc);
  68             return fdVal((FileDescriptor)fdObj);
  69         } catch (Exception x) {
  70             x.printStackTrace();
  71             throw new InternalError(x.getMessage());
  72         }
  73     }
  74 
  75     /*
  76      * Return the file descriptor underlying a given DatagramChannel
  77      */
  78     public static int getFD(DatagramChannel dc) {
  79         try {
  80             Object fdObj = get("sun.nio.ch.DatagramChannelImpl", "fd", dc);
  81             return fdVal((FileDescriptor)fdObj);
  82         } catch (Exception x) {
  83             x.printStackTrace();
  84             throw new InternalError(x.getMessage());
  85         }
  86     }
  87 
  88     /*
  89      * Return the "java" command and any initial arguments to start the runtime
  90      * in the current configuration.
  91      */
  92     public static String javaCommand() {
  93         return System.getProperty("java.home") + File.separator + "bin" +
  94             File.separator + "java";
  95     }
  96 }