AgentTransformer.java

/*
 *  Copyright 2016 the original author or authors. 
 *  @https://github.com/scouter-project/scouter
 *
 *  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 scouter.agent.batch;

import scouter.agent.batch.asm.JDBCPreparedStatementASM;
import scouter.agent.batch.asm.JDBCStatementASM;
import scouter.agent.batch.asm.JDBCResultSetASM;

import scouter.agent.asm.ScouterClassWriter;
import scouter.agent.asm.IASM;
import scouter.agent.ClassDesc;
import scouter.agent.ObjTypeDetector;
import scouter.agent.asm.util.AsmUtil;
import scouter.org.objectweb.asm.*;
import scouter.util.FileUtil;

import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.List;

public class AgentTransformer implements ClassFileTransformer {
	private static List<String> filters = new ArrayList<String>();
	private static List<IASM> asms = new ArrayList<IASM>();
    // hook 관련 설정이 변경되면 자동으로 변경된다.
 
    static {
    	asms.add(new JDBCPreparedStatementASM());
    	asms.add(new JDBCStatementASM());
    	asms.add(new JDBCResultSetASM());
    	
    	filters.add("Statement");
    	filters.add("ResultSet");
    }

    private Configure conf = Configure.getInstance();
    private Logger.FileLog bciOut;

    public byte[] transform(ClassLoader loader, String className, Class classBeingRedefined,
                            ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
        try {
        	if(!conf.sql_enabled || className == null){
        		return null;
        	}
        	
            if (className.startsWith("scouter/") || !filter(className)) {
                return null;
            }

            //classfileBuffer = DirectPatch.patch(className, classfileBuffer);
            ObjTypeDetector.check(className);
            final ClassDesc classDesc = new ClassDesc();
            ClassReader cr = new ClassReader(classfileBuffer);
            cr.accept(new ClassVisitor(Opcodes.ASM4) {
                public void visit(int version, int access, String name, String signature, String superName,
                                  String[] interfaces) {
                    classDesc.set(version, access, name, signature, superName, interfaces);
                    super.visit(version, access, name, signature, superName, interfaces);
                }

                @Override
                public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                    classDesc.anotation += desc;
                    return super.visitAnnotation(desc, visible);
                }
            }, 0);
            if (AsmUtil.isInterface(classDesc.access)) {
                return null;
            }
            classDesc.classBeingRedefined = classBeingRedefined;
            ClassWriter cw = getClassWriter(classDesc);
            ClassVisitor cv = cw;
            List<IASM> workAsms = asms;
            for (int i = 0, max = workAsms.size(); i < max; i++) {
                cv = workAsms.get(i).transform(cv, className, classDesc);
                if (cv != cw) {
                    cr = new ClassReader(classfileBuffer);
                    cr.accept(cv, ClassReader.EXPAND_FRAMES);
                    classfileBuffer = cw.toByteArray();
                    cv = cw = getClassWriter(classDesc);
                    if (conf._log_asm_enabled) {
                        if (this.bciOut == null) {
                            this.bciOut = new Logger.FileLog("./scouter.bci");
                        }
                        this.bciOut.println(className + "\t\t[" + loader + "]");
                        dump(className, classfileBuffer);
                    }
                }
            }
            return classfileBuffer;
        } catch (Throwable t) {
            Logger.println("A101", "Transformer Error", t);
            t.printStackTrace();
        }
        return null;
    }

    private ClassWriter getClassWriter(final ClassDesc classDesc) {
        ClassWriter cw;
        switch (classDesc.version) {
            case Opcodes.V1_1:
            case Opcodes.V1_2:
            case Opcodes.V1_3:
            case Opcodes.V1_4:
            case Opcodes.V1_5:
            case Opcodes.V1_6:
                cw = new ScouterClassWriter(ClassWriter.COMPUTE_MAXS);
                break;
            default:
                cw = new ScouterClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
        }
        return cw;
    }
    
    private boolean filter(String className){
    	for(String name: filters){
    		if(className.indexOf(name) >= 0){
    			return true;
    		}
    	}
    	return false;
    }

    private void dump(String className, byte[] bytes) {
        String fname = "./dump/" + className.replace('/', '_') + ".class";
        FileUtil.save(fname, bytes);
    }
}