1 /*

     2  * Copyright (c) 1999, 2012, 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 com.sun.tools.jdi;

    27 

    28 import com.sun.jdi.*;

    29 import com.sun.jdi.connect.*;

    30 import com.sun.jdi.connect.spi.*;

    31 

    32 import java.io.IOException;

    33 

    34 class SharedMemoryConnection extends Connection {

    35     private long id;

    36     private Object receiveLock = new Object();

    37     private Object sendLock = new Object();

    38     private Object closeLock = new Object();

    39     private boolean closed = false;

    40 

    41     private native byte receiveByte0(long id) throws IOException;

    42     private native void sendByte0(long id, byte b) throws IOException;

    43     private native void close0(long id);

    44     private native byte[] receivePacket0(long id)throws IOException;

    45     private native void sendPacket0(long id, byte b[]) throws IOException;

    46 

    47     // handshake with the target VM

    48     void handshake(long handshakeTimeout) throws IOException {

    49         byte[] hello = "JDWP-Handshake".getBytes("UTF-8");

    50 

    51         for (int i=0; i<hello.length; i++) {

    52             sendByte0(id, hello[i]);

    53         }

    54         for (int i=0; i<hello.length; i++) {

    55             byte b = receiveByte0(id);

    56             if (b != hello[i]) {

    57                 throw new IOException("handshake failed - unrecognized message from target VM");

    58             }

    59         }

    60     }

    61 

    62 

    63     SharedMemoryConnection(long id) throws IOException {

    64         this.id = id;

    65     }

    66 

    67     public void close() {

    68         synchronized (closeLock) {

    69             if (!closed) {

    70                 close0(id);

    71                 closed = true;

    72             }

    73         }

    74     }

    75 

    76     public boolean isOpen() {

    77         synchronized (closeLock) {

    78             return !closed;

    79         }

    80     }

    81 

    82     public byte[] readPacket() throws IOException {

    83         if (!isOpen()) {

    84             throw new ClosedConnectionException("Connection closed");

    85         }

    86         byte b[];

    87         try {

    88             // only one thread may be reading at a time

    89             synchronized (receiveLock) {

    90                 b  = receivePacket0(id);

    91             }

    92         } catch (IOException ioe) {

    93             if (!isOpen()) {

    94                 throw new ClosedConnectionException("Connection closed");

    95             } else {

    96                 throw ioe;

    97             }

    98         }

    99         return b;

   100     }

   101 

   102     public void writePacket(byte b[]) throws IOException {

   103         if (!isOpen()) {

   104             throw new ClosedConnectionException("Connection closed");

   105         }

   106 

   107         /*

   108          * Check the packet size

   109          */

   110         if (b.length < 11) {

   111             throw new IllegalArgumentException("packet is insufficient size");

   112         }

   113         int b0 = b[0] & 0xff;

   114         int b1 = b[1] & 0xff;

   115         int b2 = b[2] & 0xff;

   116         int b3 = b[3] & 0xff;

   117         int len = ((b0 << 24) | (b1 << 16) | (b2 << 8) | (b3 << 0));

   118         if (len < 11) {

   119             throw new IllegalArgumentException("packet is insufficient size");

   120         }

   121 

   122         /*

   123          * Check that the byte array contains the complete packet

   124          */

   125         if (len > b.length) {

   126             throw new IllegalArgumentException("length mis-match");

   127         }

   128 

   129         try {

   130             // only one thread may be writing at a time

   131             synchronized(sendLock) {

   132                 sendPacket0(id, b);

   133             }

   134         } catch (IOException ioe) {

   135             if (!isOpen()) {

   136                throw new ClosedConnectionException("Connection closed");

   137             } else {

   138                throw ioe;

   139             }

   140         }

   141     }

   142 }

   143