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8234687: change javap reporting on unknown attributes
Backport-of: 6025207
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Ekaterina Vergizova authored and Yuri Nesterenko committed Jan 28, 2021
1 parent 62f79b1 commit 80f30ba41052915a69a47f5aac3b2d89f252cae3
Showing with 138 additions and 5 deletions.
  1. +6 −5 src/jdk.jdeps/share/classes/com/sun/tools/javap/AttributeWriter.java
  2. +132 −0 test/langtools/tools/javap/BadAttributeName.java
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2007, 2019, 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
@@ -126,9 +126,6 @@ public void write(Object owner, Attributes attrs, ConstantPool constant_pool) {

@Override
public Void visitDefault(DefaultAttribute attr, Void ignore) {
if (attr.reason != null) {
report(attr.reason);
}
byte[] data = attr.info;
int i = 0;
int j = 0;
@@ -140,7 +137,11 @@ public Void visitDefault(DefaultAttribute attr, Void ignore) {
print("attribute name = #" + attr.attribute_name_index);
}
print(": ");
println("length = 0x" + toHex(attr.info.length));
print("length = 0x" + toHex(attr.info.length));
if (attr.reason != null) {
print(" (" + attr.reason + ")");
}
println();

print(" ");

@@ -0,0 +1,132 @@
/*
* Copyright (c) 2014, 2019, 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/

/*
* @test
* @bug 8234687
* @summary change javap reporting on unknown attributes
* @modules jdk.jdeps/com.sun.tools.javap
* @run main BadAttributeName
*/


import java.io.*;
import java.nio.file.*;

public class BadAttributeName {

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 srcFile = new File("Test.java");
Files.writeString(Path.of("Test.java"), 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");
String sourceFile = "SourceFile";
long namePos = getConstantPoolUTF8Pos(raf, sourceFile);
if (namePos < 0) {
throw new Exception("The class file contains no SourceFile attribute.");
}

raf.seek(namePos); // Jump to the SourceFile name
// Create a "custom" attribute by reusing/renaming an unimportant existing one
String customAttr = "CustomAttribute".substring(0, sourceFile.length());
raf.writeUTF(customAttr);
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();

String expect = customAttr + ": length = 0x2 (unknown attribute)";
if (sw.toString().indexOf(expect) == -1) {
sw.toString().lines().forEach(System.out::println);
throw new Exception("expected text not found: " + expect);
}
}

private static long getConstantPoolUTF8Pos(RandomAccessFile cfile, String name) 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
long fp = cfile.getFilePointer();
String s = cfile.readUTF();
if (s.equals(name)) {
return fp;
}
break;
default :
throw new Exception("Unexpected tag in CPool: [" + tag + "] at "
+ Long.toHexString(cfile.getFilePointer()));
}
}
// System.out.println();

// Bummer! Name not found!
return -1L;
}
}

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