kanela.agent.util.classloader.PreInitializeClasses Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of kanela-agent Show documentation
The Kamon Instrumentation Agent
The newest version!
/*
 * =========================================================================================
 * Copyright © 2013-2019 the kamon project 
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the
 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions
 * and limitations under the License.
 * =========================================================================================
 */

package kanela.agent.util.classloader;

import java.util.List;
import java.util.ArrayList;

import com.blogspot.mydailyjava.weaklockfree.WeakConcurrentMap;
import io.vavr.control.Try;
import kanela.agent.util.log.Logger;
import lombok.Value;
import lombok.val;

// This implementation is adapted from:
// https://github.com/glowroot/glowroot/blob/v0.9.20/agent/core/src/main/java/org/glowroot/agent/weaving/PreInitializeWeavingClasses.java

// "There are some things that agents are allowed to do that simply should not be permitted"
//
// -- http://mail.openjdk.java.net/pipermail/hotspot-dev/2012-March/005464.html
//
// in particular (at least prior to parallel class loading in JDK 7) initializing other classes
// inside of a ClassFileTransformer.transform() method occasionally leads to deadlocks
//
// this is still a problem in JDK 7+, since parallel class loading must be opted in to by custom
// class loaders, see ClassLoader.registerAsParallelCapable()
//
// to avoid initializing other classes inside of the transform() method, all classes referenced from
// WeavingClassFileTransformer are pre-initialized (and all classes referenced from those classes,
// etc)
@Value
public class PreInitializeClasses {
    // this is probably not needed, since preInitializeLinkedHashMapKeySetAndKeySetIterator() is
    // only called a single time, but just to be safe ...
    public static volatile Object toPreventDeadCodeElimination;

    public static void preInitializeClasses(ClassLoader loader) {
        for (String type : usedTypes()) {
            initialize(type, loader);
        }
        preExpiryMapKeySetAndKeySetIterator();
    }

    private static void initialize(String type, ClassLoader loader) {
        Try.of(() -> Class.forName(type, true, loader))
                .onFailure((cause) -> Logger.warn(() -> "class not found: " + type, cause));
    }

    public static List usedTypes() {
        val types = new ArrayList();
        types.addAll(getJavaUsedTypes());
        types.addAll(getBytebuddyUsedTypes());
        return types;
    }

    private static String prependByteBuddyPrefix(String s) {
        return "kanela.agent.libs.net.bytebuddy." + s;
    }

    private static List getJavaUsedTypes() {
        val types = new ArrayList();
        types.add("java.util.concurrent.locks.LockSupport");
        types.add("java.util.concurrent.ThreadLocalRandom");
        types.add("java.util.concurrent.locks.AbstractQueuedSynchronizer$Node");
        return types;
    }

    // List obtained from running:
    // grep -rh net.bytebuddy ./agent/src/ | sed s"/import net.bytebuddy.//" | sort -u
    // and adapted manually
    private static List getBytebuddyUsedTypes() {
        val types = new ArrayList();
        types.add(prependByteBuddyPrefix("agent.builder.ResettableClassFileTransformer"));
        types.add(prependByteBuddyPrefix("agent.ByteBuddyAgent"));
        types.add(prependByteBuddyPrefix("asm.Advice"));
        types.add(prependByteBuddyPrefix("asm.AsmVisitorWrapper"));
        types.add(prependByteBuddyPrefix("ByteBuddy"));
        types.add(prependByteBuddyPrefix("ClassFileVersion"));
        types.add(prependByteBuddyPrefix("description.ByteCodeElement"));
        types.add(prependByteBuddyPrefix("description.field.FieldDescription"));
        types.add(prependByteBuddyPrefix("description.field.FieldList"));
        types.add(prependByteBuddyPrefix("description.method.MethodDescription"));
        types.add(prependByteBuddyPrefix("description.method.MethodList"));
        types.add(prependByteBuddyPrefix("description.NamedElement"));
        types.add(prependByteBuddyPrefix("description.type.TypeDescription"));
        types.add(prependByteBuddyPrefix("dynamic.ClassFileLocator"));
        types.add(prependByteBuddyPrefix("dynamic.DynamicType"));
        types.add(prependByteBuddyPrefix("dynamic.loading.ClassInjector"));
        types.add(prependByteBuddyPrefix("dynamic.scaffold.MethodGraph"));
        types.add(prependByteBuddyPrefix("dynamic.scaffold.TypeValidation"));
        types.add(prependByteBuddyPrefix("implementation.bytecode.StackManipulation"));
        types.add(prependByteBuddyPrefix("implementation.Implementation"));
        types.add(prependByteBuddyPrefix("implementation.MethodDelegation"));
        types.add(prependByteBuddyPrefix("jar.asm.ClassReader"));
        types.add(prependByteBuddyPrefix("jar.asm.ClassVisitor"));
        types.add(prependByteBuddyPrefix("jar.asm.ClassWriter"));
        types.add(prependByteBuddyPrefix("jar.asm.commons.AdviceAdapter"));
        types.add(prependByteBuddyPrefix("jar.asm.commons.ClassRemapper"));
        types.add(prependByteBuddyPrefix("jar.asm.commons.Method"));
        types.add(prependByteBuddyPrefix("jar.asm.commons.MethodRemapper"));
        types.add(prependByteBuddyPrefix("jar.asm.commons.SimpleRemapper"));
        types.add(prependByteBuddyPrefix("jar.asm.Label"));
        types.add(prependByteBuddyPrefix("jar.asm.MethodVisitor"));
        types.add(prependByteBuddyPrefix("jar.asm.Opcodes"));
        types.add(prependByteBuddyPrefix("jar.asm.tree.ClassNode"));
        types.add(prependByteBuddyPrefix("jar.asm.tree.MethodNode"));
        types.add(prependByteBuddyPrefix("jar.asm.Type"));
        types.add(prependByteBuddyPrefix("matcher.ElementMatcher"));
        types.add(prependByteBuddyPrefix("matcher.ElementMatchers"));
        types.add(prependByteBuddyPrefix("pool.TypePool"));
        types.add(prependByteBuddyPrefix("utility.JavaModule"));
        types.add(prependByteBuddyPrefix("utility.OpenedClassReader"));
        return types;
    }

    private static void preExpiryMapKeySetAndKeySetIterator() {
        toPreventDeadCodeElimination = new WeakConcurrentMap(false).iterator();
    }

}