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 
get(String className, String fieldName, Object o)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 
fdVal(FileDescriptor fdObj)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      */
getFD(SocketChannel sc)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      */
getFD(ServerSocketChannel ssc)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      */
getFD(DatagramChannel dc)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      */
javaCommand()92     public static String javaCommand() {
93         return System.getProperty("java.home") + File.separator + "bin" +
94             File.separator + "java";
95     }
96 }
97