Java tutorial
/* * 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 org.objectweb.asm.ClassVisitor; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; import org.objectweb.asm.Type; import org.objectweb.asm.commons.LocalVariablesSorter; 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 java.util.List; public class CapReturnASM implements IASM, Opcodes { private List<HookingSet> target = HookingSet.getHookingMethodSet(Configure.getInstance().hook_return_patterns); public ClassVisitor transform(ClassVisitor cv, String className, ClassDesc classDesc) { if (Configure.getInstance()._hook_cap_enabled == false) { return cv; } for (int i = 0; i < target.size(); i++) { HookingSet mset = target.get(i); if (mset.classMatch.include(className)) { return new CapReturnCV(cv, mset, className); } } return cv; } } // /////////////////////////////////////////////////////////////////////////// class CapReturnCV extends ClassVisitor implements Opcodes { public String className; private HookingSet mset; public CapReturnCV(ClassVisitor cv, HookingSet mset, String className) { super(ASM7, cv); this.mset = mset; this.className = className; } @Override public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) { MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions); if (mv == null || mset.isA(name, desc) == false) { return mv; } if (AsmUtil.isSpecial(name)) { return mv; } return new CapReturnMV(access, desc, mv, className, name, desc, (access & ACC_STATIC) != 0); } } // /////////////////////////////////////////////////////////////////////////// class CapReturnMV extends LocalVariablesSorter implements Opcodes { private static final String CLASS = TraceMain.class.getName().replace('.', '/'); private static final String METHOD = "capReturn"; private static final String SIGNATURE = "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Object;Ljava/lang/Object;)V"; private Type returnType; private String className; private String methodName; private String methodDesc; private boolean isStatic; public CapReturnMV(int access, String desc, MethodVisitor mv, String classname, String methodname, String methoddesc, boolean isStatic) { super(ASM7, access, desc, mv); this.returnType = Type.getReturnType(desc); this.className = classname; this.methodName = methodname; this.methodDesc = methoddesc; this.isStatic = isStatic; } @Override public void visitInsn(int opcode) { if ((opcode >= IRETURN && opcode <= RETURN)) { capReturn(); } mv.visitInsn(opcode); } private void capReturn() { Type tp = returnType; if (tp == null || tp.equals(Type.VOID_TYPE)) { pushCommon(); mv.visitInsn(ACONST_NULL); mv.visitMethodInsn(Opcodes.INVOKESTATIC, CLASS, METHOD, SIGNATURE, false); return; } int i = newLocal(tp); switch (tp.getSort()) { case Type.BOOLEAN: mv.visitVarInsn(Opcodes.ISTORE, i); mv.visitVarInsn(Opcodes.ILOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.ILOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;", false); break; case Type.BYTE: mv.visitVarInsn(Opcodes.ISTORE, i); mv.visitVarInsn(Opcodes.ILOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.ILOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Byte", "valueOf", "(B)Ljava/lang/Byte;", false); break; case Type.CHAR: mv.visitVarInsn(Opcodes.ISTORE, i); mv.visitVarInsn(Opcodes.ILOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.ILOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Character", "valueOf", "(C)Ljava/lang/Character;", false); break; case Type.SHORT: mv.visitVarInsn(Opcodes.ISTORE, i); mv.visitVarInsn(Opcodes.ILOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.ILOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Short", "valueOf", "(S)Ljava/lang/Short;", false); break; case Type.INT: mv.visitVarInsn(Opcodes.ISTORE, i); mv.visitVarInsn(Opcodes.ILOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.ILOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;", false); break; case Type.LONG: mv.visitVarInsn(Opcodes.LSTORE, i); mv.visitVarInsn(Opcodes.LLOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.LLOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Long", "valueOf", "(J)Ljava/lang/Long;", false); break; case Type.FLOAT: mv.visitVarInsn(Opcodes.FSTORE, i); mv.visitVarInsn(Opcodes.FLOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.FLOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Float", "valueOf", "(F)Ljava/lang/Float;", false); break; case Type.DOUBLE: mv.visitVarInsn(Opcodes.DSTORE, i); mv.visitVarInsn(Opcodes.DLOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.DLOAD, i); mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Double", "valueOf", "(D)Ljava/lang/Double;", false); break; default: mv.visitVarInsn(Opcodes.ASTORE, i); mv.visitVarInsn(Opcodes.ALOAD, i); pushCommon(); mv.visitVarInsn(Opcodes.ALOAD, i); } mv.visitMethodInsn(Opcodes.INVOKESTATIC, CLASS, METHOD, SIGNATURE, false); } private void pushCommon() { AsmUtil.PUSH(mv, className); AsmUtil.PUSH(mv, methodName); AsmUtil.PUSH(mv, methodDesc); if (isStatic) { AsmUtil.PUSHNULL(mv); } else { mv.visitVarInsn(Opcodes.ALOAD, 0); } } }