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 
  26 package sun.jvmstat.perfdata.monitor.protocol.local;
  27 
  28 import sun.misc.Perf;
  29 import sun.jvmstat.monitor.*;
  30 import sun.jvmstat.perfdata.monitor.*;
  31 import java.util.*;
  32 import java.io.*;
  33 import java.nio.ByteBuffer;
  34 import java.nio.channels.FileChannel;
  35 import java.lang.reflect.Constructor;
  36 import 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")
  50 public 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 }