/*

 * Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 * questions.

 */

/*

 * @test

 * @bug 8047072

 * @summary javap OOM on fuzzed classfile

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

 * @run main BadAttributeLength

 */

import java.io.*;

public class BadAttributeLength {

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

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

                                  "}";

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

        final File sourceFile = new File("Test.java");

        if (sourceFile.exists()) {

            if (!sourceFile.delete()) {

                throw new IOException("Can't override the Test.java file. " +

                        "Check permissions.");

            }

        }

        try (FileWriter fw = new FileWriter(sourceFile)) {

            fw.write(source);

        }

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

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

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

        }

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

        long attPos = getFirstAttributePos(raf);

        if (attPos < 0) {

            throw new Exception("The class file contains no attributes at all.");

        }

        raf.seek(attPos + 2); // Jump to the attribute length

        raf.writeInt(Integer.MAX_VALUE - 1);

        raf.close();

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

        StringWriter sw = new StringWriter();

        PrintWriter pout = new PrintWriter(sw);

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

        pout.flush();

        if (sw.getBuffer().indexOf("OutOfMemoryError") != -1) {

            throw new Exception("javap exited with OutOfMemoryError " +

                    "instead of giving the proper error message.");

        }

    }

    private static long getFirstAttributePos(RandomAccessFile cfile) throws Exception {

        cfile.seek(0);

        int v1, v2;

        v1 = cfile.readInt();

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

        v1 = cfile.readUnsignedShort();

        v2 = cfile.readUnsignedShort();

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

        v1 = cfile.readUnsignedShort();

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

        // Exhaust the constant pool

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

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

            byte tag = cfile.readByte();

            switch (tag) {

                case 7  : // Class

                case 8  : // String

                    // Data is 2 bytes long

                    cfile.skipBytes(2);

                    break;

                case 3  : // Integer

                case 4  : // Float

                case 9  : // FieldRef

                case 10 : // MethodRef

                case 11 : // InterfaceMethodRef

                case 12 : // Name and Type

                    // Data is 4 bytes long

                    cfile.skipBytes(4);

                    break;

                case 5  : // Long

                case 6  : // Double

                    // Data is 8 bytes long

                    cfile.skipBytes(8);

                    break;

                case 1  : // Utf8

                    v2 = cfile.readUnsignedShort(); // Read buffer size

                    cfile.skipBytes(v2); // Skip buffer

                    break;

                default :

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

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

            }

        }

        // System.out.println();

        cfile.skipBytes(6); // Access flags, this_class and super_class

        v1 = cfile.readUnsignedShort(); // Number of interfaces

        // System.out.println("Interfaces: " + v1);

        cfile.skipBytes(3 * v1); // Each interface_info record is 3 bytes long

        v1 = cfile.readUnsignedShort(); // Number of fields

        // System.out.println("Fields: " + v1);

        // Exhaust the fields table

        for (; v1 > 0; v1--) {

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

            cfile.skipBytes(6); // Skip access_flags, name_index and descriptor_index

            v2 = cfile.readUnsignedShort(); // Field attributes count

            if (v2 > 0) {

                // This field has some attributes - suits our needs

                // System.out.println();

                return cfile.getFilePointer();

            }

        }

        // System.out.println();

        v1 = cfile.readUnsignedShort(); // Number of methods

        // System.out.println("Methods: " + v1);

        // Exhaust the methods table

        for (; v1 > 0; v1--) {

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

            cfile.skipBytes(6); // Skip access_flags, name_index and descriptor_index

            v2 = cfile.readUnsignedShort(); // Method attributes count

            if (v2 > 0) {

                // This method got attributes - Ok with us,

                // return position of the first one

                // System.out.println();

                return cfile.getFilePointer();

            }

        }

        // System.out.println();

        // Class attributes section

        v1 = cfile.readUnsignedShort(); // Counts of attributes in class

        if (v1 > 0) {

            // Class has some attributes, return position of the first one

            return cfile.getFilePointer();

        }

        // Bummer! No attributes in the entire class file. Not fair!

        return -1L;

    }

}