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/*
* Copyright (c) 2005, 2024, 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.
*/
import asmlib.Instrumentor;
import java.lang.constant.ClassDesc;
import java.lang.constant.MethodTypeDesc;
import java.lang.instrument.*;
import java.security.ProtectionDomain;
import java.io.*;
import static java.lang.constant.ConstantDescs.*;
class NativeMethodPrefixAgent {
static ClassFileTransformer t0, t1, t2;
static Instrumentation inst;
private static Throwable agentError; // to be accessed/updated in a synchronized block
private static final String CLASS_TO_TRANSFORM = "NativeMethodPrefixApp$Dummy";
public static synchronized void checkErrors() {
if (agentError != null) {
throw new RuntimeException("Agent error", agentError);
}
}
private static synchronized void trackError(final Throwable t) {
if (agentError == null) {
agentError = t;
return;
}
if (agentError != t) {
agentError.addSuppressed(t);
}
}
static class Tr implements ClassFileTransformer {
private static final ClassDesc CD_StringIdCallbackReporter = ClassDesc.ofInternalName("bootreporter/StringIdCallbackReporter");
private static final MethodTypeDesc MTD_void_String_int = MethodTypeDesc.of(CD_void, CD_String, CD_int);
final String trname;
final int transformId;
private final String nativeMethodPrefix;
Tr(int transformId) {
this.trname = "tr" + transformId;
this.transformId = transformId;
this.nativeMethodPrefix = "wrapped_" + trname + "_";
}
@Override
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
ProtectionDomain protectionDomain, byte[] classfileBuffer) {
try {
// we only transform a specific application class
if (!className.equals(CLASS_TO_TRANSFORM)) {
return null;
}
if (classBeingRedefined != null) {
return null;
}
// use a byte code generator which creates wrapper methods,
// with a configured native method prefix, for each native method on the
// class being transformed
final Instrumentor byteCodeGenerator = Instrumentor.instrFor(classfileBuffer)
.addNativeMethodTrackingInjection(nativeMethodPrefix,
(name, cb) -> {
cb.loadConstant(name);
cb.loadConstant(transformId);
cb.invokestatic(CD_StringIdCallbackReporter,
"tracker", MTD_void_String_int);
});
// generate the bytecode
return byteCodeGenerator.apply();
} catch (Throwable t) {
trackError(t);
return null;
}
}
}
// for debugging
static void write_buffer(String fname, byte[]buffer) {
try {
File f = new File(fname);
if (!f.getParentFile().exists()) {
f.getParentFile().mkdirs();
}
try (FileOutputStream outStream = new FileOutputStream(f)) {
outStream.write(buffer, 0, buffer.length);
}
} catch (IOException ex) {
System.err.println("EXCEPTION in write_buffer: " + ex);
}
}
public static void
premain (String agentArgs, Instrumentation instArg)
throws IOException, IllegalClassFormatException,
ClassNotFoundException, UnmodifiableClassException {
inst = instArg;
System.out.println("Premain");
t1 = new Tr(1);
t2 = new Tr(2);
t0 = new Tr(0);
inst.addTransformer(t1, true);
inst.addTransformer(t2, false);
inst.addTransformer(t0, true);
instArg.setNativeMethodPrefix(t0, "wrapped_tr0_");
instArg.setNativeMethodPrefix(t1, "wrapped_tr1_");
instArg.setNativeMethodPrefix(t2, "wrapped_tr2_");
// warm up: cause load of transformer classes before used during class load
instArg.retransformClasses(Runtime.class);
}
}
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