1 /*

     2  * Copyright (c) 2014, 2019, 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  * @test

    26  * @bug 8234687

    27  * @summary change javap reporting on unknown attributes

    28  * @modules jdk.jdeps/com.sun.tools.javap

    29  * @run main BadAttributeName

    30  */

    31 

    32 

    33 import java.io.*;

    34 import java.nio.file.*;

    35 

    36 public class BadAttributeName {

    37 

    38     public static String source = "public class Test {\n" +

    39                                   "    public static void main(String[] args) {}\n" +

    40                                   "}";

    41 

    42     public static void main(String[] args) throws Exception {

    43         final File srcFile = new File("Test.java");

    44         Files.writeString(Path.of("Test.java"), source);

    45 

    46         final String[] javacOpts = {"Test.java"};

    47 

    48         if (com.sun.tools.javac.Main.compile(javacOpts) != 0) {

    49             throw new Exception("Can't compile embedded test.");

    50         }

    51 

    52         RandomAccessFile raf = new RandomAccessFile("Test.class", "rw");

    53         String sourceFile = "SourceFile";

    54         long namePos = getConstantPoolUTF8Pos(raf, sourceFile);

    55         if (namePos < 0) {

    56             throw new Exception("The class file contains no SourceFile attribute.");

    57         }

    58 

    59         raf.seek(namePos); // Jump to the SourceFile name

    60         // Create a "custom" attribute by reusing/renaming an unimportant existing one

    61         String customAttr = "CustomAttribute".substring(0, sourceFile.length());

    62         raf.writeUTF(customAttr);

    63         raf.close();

    64 

    65         String[] opts = { "-v", "Test.class" };

    66         StringWriter sw = new StringWriter();

    67         PrintWriter pout = new PrintWriter(sw);

    68 

    69         com.sun.tools.javap.Main.run(opts, pout);

    70         pout.flush();

    71 

    72         String expect = customAttr + ": length = 0x2 (unknown attribute)";

    73         if (sw.toString().indexOf(expect) == -1) {

    74             sw.toString().lines().forEach(System.out::println);

    75             throw new Exception("expected text not found: " + expect);

    76         }

    77     }

    78 

    79     private static long getConstantPoolUTF8Pos(RandomAccessFile cfile, String name) throws Exception {

    80         cfile.seek(0);

    81         int v1, v2;

    82         v1 = cfile.readInt();

    83         // System.out.println("Magic: " + String.format("%X", v1));

    84 

    85         v1 = cfile.readUnsignedShort();

    86         v2 = cfile.readUnsignedShort();

    87         // System.out.println("Version: " + String.format("%d.%d", v1, v2));

    88 

    89         v1 = cfile.readUnsignedShort();

    90         // System.out.println("CPool size: " + v1);

    91         // Exhaust the constant pool

    92         for (; v1 > 1; v1--) {

    93             // System.out.print(".");

    94             byte tag = cfile.readByte();

    95             switch (tag) {

    96                 case 7  : // Class

    97                 case 8  : // String

    98                     // Data is 2 bytes long

    99                     cfile.skipBytes(2);

   100                     break;

   101                 case 3  : // Integer

   102                 case 4  : // Float

   103                 case 9  : // FieldRef

   104                 case 10 : // MethodRef

   105                 case 11 : // InterfaceMethodRef

   106                 case 12 : // Name and Type

   107                     // Data is 4 bytes long

   108                     cfile.skipBytes(4);

   109                     break;

   110                 case 5  : // Long

   111                 case 6  : // Double

   112                     // Data is 8 bytes long

   113                     cfile.skipBytes(8);

   114                     break;

   115                 case 1  : // Utf8

   116                     long fp = cfile.getFilePointer();

   117                     String s = cfile.readUTF();

   118                     if (s.equals(name)) {

   119                         return fp;

   120                     }

   121                     break;

   122                 default :

   123                     throw new Exception("Unexpected tag in CPool: [" + tag + "] at "

   124                             + Long.toHexString(cfile.getFilePointer()));

   125             }

   126         }

   127         // System.out.println();

   128 

   129         // Bummer! Name not found!

   130         return -1L;

   131     }

   132 }