JspServletASM.java

/*
 *  Copyright 2015 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.asm;

import scouter.agent.ClassDesc;
import scouter.agent.Configure;
import scouter.agent.asm.util.AsmUtil;
import scouter.agent.asm.util.HookingSet;
import scouter.agent.trace.TraceMain;
import scouter.org.objectweb.asm.ClassVisitor;
import scouter.org.objectweb.asm.MethodVisitor;
import scouter.org.objectweb.asm.Opcodes;
import scouter.org.objectweb.asm.Type;
import scouter.org.objectweb.asm.commons.LocalVariablesSorter;
import scouter.util.Pair;

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

public class JspServletASM implements IASM, Opcodes {
	private Map<String, HookingSet> target = HookingSet.getHookingSet(Configure.getInstance().hook_jsp_patterns);

    public static class JspTargetRegister {
        public static final List<Pair<String,String>> klassMethod = new ArrayList<Pair<String,String>>();
        public static void regist(String klass, String method) {
            klassMethod.add(new Pair<String, String>(klass, method));
        }
    }

	public JspServletASM() {
        AsmUtil.add(target, "org/apache/jasper/servlet/JspServlet", "serviceJspFile");

        for(int i = JspTargetRegister.klassMethod.size() - 1; i >= 0; i--) {
            AsmUtil.add(target, JspTargetRegister.klassMethod.get(i).getLeft(), JspTargetRegister.klassMethod.get(i).getRight());
        }
	}

	public ClassVisitor transform(ClassVisitor cv, String className, ClassDesc classDesc) {
		if (Configure.getInstance()._hook_jsp_enabled == false) {
			return cv;
		}
		HookingSet mset = target.get(className);
		if (mset == null)
			return cv;
		else
			return new JspServletCV(cv, mset, className);

	}

}

// ///////////////////////////////////////////////////////////////////////////
class JspServletCV extends ClassVisitor implements Opcodes {

	public String className;
	private HookingSet mset;

	public JspServletCV(ClassVisitor cv, HookingSet mset, String className) {
		super(ASM4, cv);
		this.mset = mset;
		this.className = className;
	}

	@Override
	public MethodVisitor visitMethod(int access, String methodName, String desc, String signature, String[] exceptions) {
		MethodVisitor mv = super.visitMethod(access, methodName, desc, signature, exceptions);
		if (mv == null || mset.isA(methodName, desc) == false) {
			return mv;
		}
		if (AsmUtil.isSpecial(methodName)) {
			return mv;
		}
		return new JspServletMV(access, desc, mv, Type.getArgumentTypes(desc), (access & ACC_STATIC) != 0);
	}
}

// ///////////////////////////////////////////////////////////////////////////
class JspServletMV extends LocalVariablesSorter implements Opcodes {
	private static final String CLASS = TraceMain.class.getName().replace('.', '/');
	private static final String METHOD = "jspServlet";
	private static final String SIGNATURE = "([Ljava/lang/Object;)V";

	private Type[] paramTypes;
	private boolean isStatic;

	public JspServletMV(int access, String desc, MethodVisitor mv, Type[] paramTypes, boolean isStatic) {
		super(ASM4, access, desc, mv);
		this.paramTypes = paramTypes;
		this.isStatic = isStatic;

	}

	@Override
	public void visitCode() {

		int sidx = isStatic ? 0 : 1;

		int arrVarIdx = newLocal(Type.getType("[Ljava/lang/Object;"));
		AsmUtil.PUSH(mv, paramTypes.length);
		mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
		mv.visitVarInsn(Opcodes.ASTORE, arrVarIdx);

		for (int i = 0; i < paramTypes.length; i++) {
			Type tp = paramTypes[i];
			mv.visitVarInsn(Opcodes.ALOAD, arrVarIdx);
			AsmUtil.PUSH(mv, i);

			switch (tp.getSort()) {
			case Type.BOOLEAN:
				mv.visitVarInsn(Opcodes.ILOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;",false);
				break;
			case Type.BYTE:
				mv.visitVarInsn(Opcodes.ILOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Byte", "valueOf", "(B)Ljava/lang/Byte;",false);
				break;
			case Type.CHAR:
				mv.visitVarInsn(Opcodes.ILOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Character", "valueOf", "(C)Ljava/lang/Character;",false);
				break;
			case Type.SHORT:
				mv.visitVarInsn(Opcodes.ILOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Short", "valueOf", "(S)Ljava/lang/Short;",false);
				break;
			case Type.INT:
				mv.visitVarInsn(Opcodes.ILOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;",false);
				break;
			case Type.LONG:
				mv.visitVarInsn(Opcodes.LLOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Long", "valueOf", "(J)Ljava/lang/Long;",false);
				break;
			case Type.FLOAT:
				mv.visitVarInsn(Opcodes.FLOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Float", "valueOf", "(F)Ljava/lang/Float;",false);
				break;
			case Type.DOUBLE:
				mv.visitVarInsn(Opcodes.DLOAD, sidx);
				mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Double", "valueOf", "(D)Ljava/lang/Double;",false);
				break;
			default:
				mv.visitVarInsn(Opcodes.ALOAD, sidx);
			}
			mv.visitInsn(Opcodes.AASTORE);
			sidx += tp.getSize();
		}
		mv.visitVarInsn(Opcodes.ALOAD, arrVarIdx);

		mv.visitMethodInsn(Opcodes.INVOKESTATIC, CLASS, METHOD, SIGNATURE,false);
		super.visitCode();
	}
}