1 /*

     2  * Copyright (c) 2001, 2018, 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 package nsk.share.jdwp;

    25 

    26 import nsk.share.*;

    27 

    28 import java.io.IOException;

    29 //import java.util.Vector;

    30 

    31 /**

    32  * This class represents an abstract transport for JDWP.

    33  */

    34 public abstract class Transport extends Log.Logger {

    35 

    36     public static final String LOG_PREFIX = "transport> ";

    37 

    38     /**

    39      * Make base <code>Transport</code> object providing with specified Log.

    40      */

    41     public Transport(Log log) {

    42         super(log, LOG_PREFIX);

    43     }

    44 

    45     /**

    46      * Return number of bytes that can be received.

    47      */

    48     public abstract int available() throws IOException;

    49 

    50     /**

    51      * Flushe bytes being buffered for writing if any.

    52      */

    53     public abstract void flush() throws IOException;

    54 

    55     /**

    56      * Receive the next byte of data.

    57      *

    58      * The value byte is returned as an int in the range 0 to 255.

    59      * If no byte is available, the value -1 is returned.

    60      */

    61     public abstract byte read() throws IOException;

    62 

    63     /**

    64      * Send the specified byte.

    65      */

    66     public abstract void write(int b) throws IOException;

    67 

    68     /**

    69      * Send the specified bytes.

    70      */

    71     public void write(byte[] b, int off, int len) throws IOException {

    72         for (int i = 0; i < len; i++)

    73             write(b[off + i]);

    74     }

    75 

    76     /**

    77      * Receive bytes of JDWP packet for default timeout.

    78      */

    79     public void read(Packet packet) throws IOException {

    80         packet.readFrom(this);

    81     }

    82 

    83     /**

    84      * Send and flushe bytes of JDWP packet.

    85      */

    86     public void write(Packet packet) throws IOException {

    87         packet.writeTo(this);

    88         flush();

    89     }

    90 

    91     /**

    92      * Perform JDWP "handshake" procedure.

    93      */

    94     public void handshake() throws IOException {

    95 

    96         String hs = "JDWP-Handshake";

    97         byte[] hsb = hs.getBytes();

    98 

    99         write(hsb, 0, hsb.length);

   100         flush();

   101 

   102         try {

   103             Thread.currentThread().sleep(500);

   104         } catch (InterruptedException e) {

   105             throw new Failure(e);

   106         }

   107 

   108         int received = 0;

   109         for (int i = 0; i < Binder.CONNECT_TRIES; i++) {

   110             received = available();

   111             if (received < hsb.length) {

   112 //                System.err.println("Failed to hadshake try #" + i + ", bytes: " + received);

   113                 try {

   114                     Thread.currentThread().sleep(Binder.CONNECT_TRY_DELAY);

   115                 } catch (InterruptedException e) {

   116                     throw new Failure("Thread interrupted while sleeping between connection attempts:\n\t"

   117                                     + e);

   118                 }

   119             } else {

   120 //                System.err.println("Successed to hadshake try #" + i + ", bytes: " + received);

   121                 for (int j = 0; j < hsb.length; j++) {

   122                     byte b = (byte) (read() & 0xFF);

   123                     if (b != hsb[j])

   124                         throw new IOException("Target VM failed to handshake: unexpected byte #" + j

   125                                             + ": " + b + " (expected:" + hsb[j] + ")");

   126                 }

   127                 return;

   128             }

   129         }

   130 

   131         throw new IOException("Target VM failed to handshake: too few bytes in reply: "

   132                             + received + "(expected: " + hsb.length + ")");

   133     }

   134 

   135     /**

   136      * Set timeout for reading data in milliseconds.

   137      * Timeout of 0 means wait infinitly.

   138      */

   139     public abstract void setReadTimeout(long millisecs) throws IOException;

   140 

   141     /**

   142      * Close JDWP connection.

   143      */

   144     public abstract void close() throws IOException;

   145 

   146     /**

   147      * Perform finalization of object by closing JDWP connection.

   148      */

   149     protected void finalize() throws Throwable {

   150         close();

   151     }

   152 

   153 }