1 /*

     2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  *

     8  *   - Redistributions of source code must retain the above copyright

     9  *     notice, this list of conditions and the following disclaimer.

    10  *

    11  *   - Redistributions in binary form must reproduce the above copyright

    12  *     notice, this list of conditions and the following disclaimer in the

    13  *     documentation and/or other materials provided with the distribution.

    14  *

    15  *   - Neither the name of Oracle nor the names of its

    16  *     contributors may be used to endorse or promote products derived

    17  *     from this software without specific prior written permission.

    18  *

    19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    20  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

    21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

    23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

    27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

    28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

    29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    30  */

    31 

    32 // Usage: jjs disassemble.js -- <.class-file-path>

    33 

    34 // Simple .class disassembler that uses bundled ObjectWeb ASM

    35 // classes in jdk8. WARNING: Bundled ObjectWeb ASM classes are

    36 // not part of official jdk8 API. It can be changed/removed

    37 // without notice. So, this script is brittle by design!

    38 

    39 // This example demonstrates passing arguments to script

    40 // from jjs command line, nio and ASM usage.

    41 

    42 // classes used

    43 var FileSystems = Java.type("java.nio.file.FileSystems");

    44 var Files = Java.type("java.nio.file.Files");

    45 var System = Java.type("java.lang.System");

    46 var PrintWriter = Java.type("java.io.PrintWriter");

    47 

    48 // WARNING: uses non-API classes of jdk8!

    49 var ClassReader = Java.type("jdk.internal.org.objectweb.asm.ClassReader");

    50 var TraceClassVisitor = Java.type("jdk.internal.org.objectweb.asm.util.TraceClassVisitor");

    51 

    52 // convert file name to Path instance

    53 function path(file) {

    54     return FileSystems.default.getPath(file);

    55 }

    56 

    57 // read all file content as a byte[]

    58 function readAllBytes(file) {

    59     return Files.readAllBytes(path(file));

    60 }

    61 

    62 // disassemble .class byte[] and prints output to stdout

    63 function disassemble(bytecode) {

    64     var pw = new PrintWriter(System.out);

    65     new ClassReader(bytecode).accept(new TraceClassVisitor(pw), 0);

    66 }

    67 

    68 // check for command line arg (for .class file name)

    69 if (arguments.length == 0 || !arguments[0].endsWith('.class')) {

    70     print("Usage: jjs disassemble -- <.class file>");

    71     exit(1);

    72 }

    73 

    74 // disassemble the given .class file

    75 disassemble(readAllBytes(arguments[0]));