1/*
2 * Copyright (c) 2004, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.jvmstat.perfdata.monitor.protocol.local;
27
28import jdk.internal.perf.Perf;
29import sun.jvmstat.monitor.*;
30import sun.jvmstat.perfdata.monitor.*;
31import java.util.*;
32import java.io.*;
33import java.nio.ByteBuffer;
34import java.nio.channels.FileChannel;
35import java.lang.reflect.Constructor;
36import java.security.AccessController;
37
38/**
39 * The concrete PerfDataBuffer implementation for the <em>local:</em>
40 * protocol for the HotSpot PerfData monitoring implementation.
41 * <p>
42 * This class is responsible for acquiring access to the shared memory
43 * instrumentation buffer for the target HotSpot Java Virtual Machine.
44 *
45 * @author Brian Doherty
46 * @since 1.5
47 */
48// Suppreess unchecked conversion warning at line 34.
49//@SuppressWarnings("unchecked")
50public class PerfDataBuffer extends AbstractPerfDataBuffer {
51    private static final Perf perf = AccessController.doPrivileged(new Perf.GetPerfAction());
52
53    /**
54     * Create a PerfDataBuffer instance for accessing the specified
55     * instrumentation buffer.
56     *
57     * @param vmid the <em>local:</em> URI specifying the target JVM.
58     *
59     * @throws MonitorException
60     */
61    public PerfDataBuffer(VmIdentifier vmid) throws MonitorException {
62        try {
63            // Try 1.4.2 and later first
64            ByteBuffer bb = perf.attach(vmid.getLocalVmId(), vmid.getMode());
65            createPerfDataBuffer(bb, vmid.getLocalVmId());
66
67        } catch (IllegalArgumentException e) {
68            // now try 1.4.1 by attempting to directly map the files.
69            try {
70                String filename = PerfDataFile.getTempDirectory()
71                                  + PerfDataFile.dirNamePrefix
72                                  + Integer.toString(vmid.getLocalVmId());
73
74                File f = new File(filename);
75
76                FileChannel fc = new RandomAccessFile(f, "r").getChannel();
77                ByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0L,
78                                       (int)fc.size());
79                fc.close();
80                createPerfDataBuffer(bb, vmid.getLocalVmId());
81
82            } catch (FileNotFoundException e2) {
83                // re-throw the exception from the 1.4.2 attach method
84                throw new MonitorException(vmid.getLocalVmId() + " not found",
85                                           e);
86            } catch (IOException e2) {
87                throw new MonitorException("Could not map 1.4.1 file for "
88                                           + vmid.getLocalVmId(), e2);
89            }
90        } catch (IOException e) {
91            throw new MonitorException("Could not attach to "
92                                       + vmid.getLocalVmId(), e);
93        }
94    }
95}
96