Java tutorial
/* * JBoss, Home of Professional Open Source * Copyright 2009-10 Red Hat and individual contributors * by the @authors tag. See the copyright.txt in the distribution for a * full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. * * @authors Andrew Dinn */ package org.jboss.byteman.rule.compiler; import org.jboss.byteman.rule.Rule; import org.jboss.byteman.rule.binding.Binding; import org.jboss.byteman.rule.binding.Bindings; import org.jboss.byteman.rule.exception.CompileException; import org.jboss.byteman.agent.Transformer; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.*; import java.lang.reflect.Constructor; import java.util.Iterator; /** * A class which compiles a rule by generating a subclass of the rule's helperClass which implements * the HelperAdapter interface */ public class Compiler implements Opcodes { public static Class getHelperAdapter(Rule rule, Class helperClass, boolean compileToBytecode) throws CompileException { Class adapterClass; // ok we have to create the adapter class // n.b. we don't bother synchronizing here -- if another rule is racing to create an adapter // in parallel we don't really care about generating two of them -- we can use whichever // one gets installed last try { String helperName = Type.getInternalName(helperClass); String compiledHelperName; // we put the helper in the if (compileToBytecode) { compiledHelperName = helperName + "_HelperAdapter_Compiled_" + nextId(); } else { compiledHelperName = helperName + "_HelperAdapter_Interpreted_" + nextId(); } byte[] classBytes = compileBytes(rule, helperClass, helperName, compiledHelperName, compileToBytecode); String externalName = compiledHelperName.replace('/', '.'); // dump the compiled class bytes if required Transformer.maybeDumpClass(externalName, classBytes); // ensure the class is loaded // think we need to load the generated helper using the class loader of the trigger class ClassLoader loader = rule.getLoader(); adapterClass = loadHelperAdapter(loader, externalName, classBytes); } catch (CompileException ce) { throw ce; } catch (Throwable th) { if (compileToBytecode) { throw new CompileException( "Compiler.createHelperAdapter : exception creating compiled helper adapter for " + helperClass.getName(), th); } else { throw new CompileException( "Compiler.createHelperAdapter : exception creating interpreted helper adapter for " + helperClass.getName(), th); } } return adapterClass; } private static byte[] compileBytes(Rule rule, Class helperClass, String helperName, String compiledHelperName, boolean compileToBytecode) throws Exception { ClassWriter cw = new ClassWriter(0); FieldVisitor fv; MethodVisitor mv; AnnotationVisitor av0; // create the class as a subclass of the rule helper class, appending Compiled to the front // of the class name and a unique number to the end of the class helperName // also ensure it implements the HelperAdapter interface // // public class foo.bar.Compiled_<helper>_<NNN> extends foo.bar.<helper> implements HelperAdapter cw.visit(V1_5, ACC_PUBLIC + ACC_SUPER, compiledHelperName, null, helperName, new String[] { "org/jboss/byteman/rule/helper/HelperAdapter" }); // we need to install the source file name { String fullFileName = rule.getFile(); int idx = fullFileName.lastIndexOf(java.io.File.separatorChar); String basicFileName = (idx < 0 ? fullFileName : fullFileName.substring(idx + 1)); String debug = "// compiled from: " + fullFileName + "\n// generated by Byteman\n"; cw.visitSource(basicFileName, debug); } { // we need a Hashmap field to hold the bindings // // private HashMap<String, Object> bindingMap; fv = cw.visitField(ACC_PRIVATE, "bindingMap", "Ljava/util/HashMap;", "Ljava/util/HashMap<Ljava/lang/String;Ljava/lang/Object;>;", null); fv.visitEnd(); } { // and a rule field to hold the rule // // private Rule rule; fv = cw.visitField(ACC_PRIVATE, "rule", "Lorg/jboss/byteman/rule/Rule;", "Lorg/jboss/byteman/rule/Rule;", null); fv.visitEnd(); } { // we need a constructor which takes a Rule as argument // if the helper implements a constructor which takes a Rule as argument then we invoke it // otherwise we invoke the empty helper constructor Constructor superConstructor = null; try { superConstructor = helperClass.getDeclaredConstructor(Rule.class); } catch (NoSuchMethodException e) { // hmm, ok see if there is an empty constructor } catch (SecurityException e) { throw new CompileException("Compiler.compileBytes : unable to access constructor for helper class " + helperClass.getCanonicalName()); } boolean superWantsRule = (superConstructor != null); if (!superWantsRule) { try { superConstructor = helperClass.getDeclaredConstructor(); } catch (NoSuchMethodException e) { throw new CompileException( "Compiler.compileBytes : no valid constructor found for helper class " + helperClass.getCanonicalName()); } catch (SecurityException e) { throw new CompileException( "Compiler.compileBytes : unable to access constructor for helper class " + helperClass.getCanonicalName()); } } // // public Compiled<helper>_<NNN>()Rule rule) mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Lorg/jboss/byteman/rule/Rule;)V", null, null); mv.visitCode(); // super(); // // or // // super(Rule); if (superWantsRule) { mv.visitVarInsn(ALOAD, 0); mv.visitVarInsn(ALOAD, 1); mv.visitMethodInsn(INVOKESPECIAL, helperName, "<init>", "(Lorg/jboss/byteman/rule/Rule;)V"); } else { mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, helperName, "<init>", "()V"); } // bindingMap = new HashMap<String, Object); mv.visitVarInsn(ALOAD, 0); mv.visitTypeInsn(NEW, "java/util/HashMap"); mv.visitInsn(DUP); mv.visitMethodInsn(INVOKESPECIAL, "java/util/HashMap", "<init>", "()V"); mv.visitFieldInsn(PUTFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); // this.rule = rule mv.visitVarInsn(ALOAD, 0); mv.visitVarInsn(ALOAD, 1); mv.visitFieldInsn(PUTFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); // return; mv.visitInsn(RETURN); mv.visitMaxs(3, 2); mv.visitEnd(); } { // create the execute method // // public void execute(Bindings bindings, Object recipient, Object[] args) throws ExecuteException mv = cw.visitMethod(ACC_PUBLIC, "execute", "(Ljava/lang/Object;[Ljava/lang/Object;)V", null, new String[] { "org/jboss/byteman/rule/exception/ExecuteException" }); mv.visitCode(); // if (Transformer.isVerbose()) mv.visitMethodInsn(INVOKESTATIC, "org/jboss/byteman/agent/Transformer", "isVerbose", "()Z"); Label l0 = new Label(); mv.visitJumpInsn(IFEQ, l0); // then // System.out.println(rule.getName() + " execute"); mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;"); mv.visitTypeInsn(NEW, "java/lang/StringBuilder"); mv.visitInsn(DUP); mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "()V"); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "getName", "()Ljava/lang/String;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;"); mv.visitLdcInsn(" execute()"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V"); // end if mv.visitLabel(l0); Bindings bindings = rule.getBindings(); Iterator<Binding> iterator = bindings.iterator(); while (iterator.hasNext()) { Binding binding = iterator.next(); String name = binding.getName(); if (binding.isAlias()) { // lookups and updates will use the aliased name continue; } if (binding.isHelper()) { // bindingMap.put(name, this); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); mv.visitLdcInsn(name); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/HashMap", "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"); mv.visitInsn(POP); } else if (binding.isRecipient()) { // bindingMap.put(name, recipient); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); mv.visitLdcInsn(name); mv.visitVarInsn(ALOAD, 1); mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/HashMap", "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"); mv.visitInsn(POP); // } else if (binding.isParam() || binding.isLocalVar() || binding.isReturn() || // binding.isThrowable() || binding.isParamCount() || binding.isParamArray()) { } else if (!binding.isBindVar()) { // bindingMap.put(name, args[binding.getCallArrayIndex()]); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); mv.visitLdcInsn(name); mv.visitVarInsn(ALOAD, 2); mv.visitLdcInsn(binding.getCallArrayIndex()); mv.visitInsn(AALOAD); mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/HashMap", "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"); mv.visitInsn(POP); } } // execute0() mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKEVIRTUAL, compiledHelperName, "execute0", "()V"); // now restore update bindings iterator = bindings.iterator(); while (iterator.hasNext()) { Binding binding = iterator.next(); if (binding.isAlias()) { continue; } String name = binding.getName(); if (binding.isUpdated()) { // if (binding.isParam() || binding.isLocalVar() || binding.isReturn()) { if (!binding.isBindVar()) { int idx = binding.getCallArrayIndex(); // Object value = bindingMap.get(name); // args[idx] = value; mv.visitVarInsn(ALOAD, 2); // args mv.visitLdcInsn(idx); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); mv.visitLdcInsn(name); mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/HashMap", "get", "(Ljava/lang/Object;)Ljava/lang/Object;"); mv.visitInsn(AASTORE); } } } // return mv.visitInsn(RETURN); mv.visitMaxs(4, 3); mv.visitEnd(); } { // create the setBinding method // // public void setBinding(String name, Object value) mv = cw.visitMethod(ACC_PUBLIC, "setBinding", "(Ljava/lang/String;Ljava/lang/Object;)V", null, null); mv.visitCode(); // bindingMap.put(name, value); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); mv.visitVarInsn(ALOAD, 1); mv.visitVarInsn(ALOAD, 2); mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/HashMap", "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"); mv.visitInsn(POP); // return mv.visitInsn(RETURN); mv.visitMaxs(3, 3); mv.visitEnd(); } { // create the getBinding method // // public Object getBinding(String name) mv = cw.visitMethod(ACC_PUBLIC, "getBinding", "(Ljava/lang/String;)Ljava/lang/Object;", null, null); mv.visitCode(); // {TOS} <== bindingMap.get(name); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "bindingMap", "Ljava/util/HashMap;"); mv.visitVarInsn(ALOAD, 1); mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/HashMap", "get", "(Ljava/lang/Object;)Ljava/lang/Object;"); // return {TOS} mv.visitInsn(ARETURN); mv.visitMaxs(2, 2); mv.visitEnd(); } { // create the getName method // // public String getName() mv = cw.visitMethod(ACC_PUBLIC, "getName", "()Ljava/lang/String;", null, null); mv.visitCode(); // {TOS} <== rule.getName() mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "getName", "()Ljava/lang/String;"); // return {TOS} mv.visitInsn(ARETURN); mv.visitMaxs(1, 1); mv.visitEnd(); } // create the getAccessibleField method // // public Object getAccessibleField(Object owner, int fieldIndex) { mv = cw.visitMethod(ACC_PUBLIC, "getAccessibleField", "(Ljava/lang/Object;I)Ljava/lang/Object;", null, null); mv.visitCode(); // {TOS} <== rule.getAccessibleField(owner, fieldIndex); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitVarInsn(ALOAD, 1); mv.visitVarInsn(ILOAD, 2); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "getAccessibleField", "(Ljava/lang/Object;I)Ljava/lang/Object;"); // return {TOS} mv.visitInsn(ARETURN); mv.visitMaxs(3, 3); mv.visitEnd(); } // create the setAccessibleField method // // public void setAccessibleField(Object owner, Object value, int fieldIndex) // rule.setAccessibleField(owner, value, fieldIndex); { mv = cw.visitMethod(ACC_PUBLIC, "setAccessibleField", "(Ljava/lang/Object;Ljava/lang/Object;I)V", null, null); mv.visitCode(); // rule.setAccessibleField(owner, value, fieldIndex); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitVarInsn(ALOAD, 1); mv.visitVarInsn(ALOAD, 2); mv.visitVarInsn(ILOAD, 3); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "setAccessibleField", "(Ljava/lang/Object;Ljava/lang/Object;I)V"); // return mv.visitInsn(RETURN); mv.visitMaxs(4, 4); mv.visitEnd(); } // create the invokeAccessibleMethod method // // public Object invokeAccessibleMethod(Object target, Object[] args, int methodIndex) // {TOS} <== rule.invokeAccessibleMethod(target, args, methodIndex); { mv = cw.visitMethod(ACC_PUBLIC, "invokeAccessibleMethod", "(Ljava/lang/Object;[Ljava/lang/Object;I)Ljava/lang/Object;", null, null); mv.visitCode(); // rule.invokeAccessibleMethod(target, args, fieldIndex); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitVarInsn(ALOAD, 1); mv.visitVarInsn(ALOAD, 2); mv.visitVarInsn(ILOAD, 3); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "invokeAccessibleMethod", "(Ljava/lang/Object;[Ljava/lang/Object;I)Ljava/lang/Object;"); // return {TOS} mv.visitInsn(ARETURN); mv.visitMaxs(4, 4); mv.visitEnd(); } if (compileToBytecode) { // we generate a single execute0 method if we want to run compiled and get // the event, condiiton and action to insert the relevant bytecode to implement // bind(), test() and fire() { // create the execute0() method // // private void execute0() mv = cw.visitMethod(ACC_PRIVATE, "execute0", "()V", null, new String[] { "org/jboss/byteman/rule/exception/ExecuteException" }); mv.visitCode(); CompileContext compileContext = new CompileContext(mv); // make sure we set the first line number before generating any code compileContext.notifySourceLine(rule.getLine()); compileContext.addLocalCount(3); // for this and 2 object args // bind(); rule.getEvent().compile(mv, compileContext); // if (test()) rule.getCondition().compile(mv, compileContext); Label l0 = new Label(); mv.visitJumpInsn(IFEQ, l0); compileContext.addStackCount(-1); // then rule.getAction().compile(mv, compileContext); // fire(); // end if mv.visitLabel(l0); // this will match the ENDRULE line compileContext.notifySourceEnd(); // return mv.visitInsn(RETURN); // need to specify correct Maxs values mv.visitMaxs(compileContext.getStackMax(), compileContext.getLocalMax()); mv.visitEnd(); } } else { // we generate the following methods if we want to run interpreted { // create the execute0() method // // private void execute0() mv = cw.visitMethod(ACC_PRIVATE, "execute0", "()V", null, new String[] { "org/jboss/byteman/rule/exception/ExecuteException" }); mv.visitCode(); // bind(); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, compiledHelperName, "bind", "()V"); // if (test()) mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, compiledHelperName, "test", "()Z"); Label l0 = new Label(); mv.visitJumpInsn(IFEQ, l0); // then // fire(); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, compiledHelperName, "fire", "()V"); // end if mv.visitLabel(l0); // return mv.visitInsn(RETURN); mv.visitMaxs(1, 1); mv.visitEnd(); } { // create the bind method // // private void bind() mv = cw.visitMethod(ACC_PRIVATE, "bind", "()V", null, new String[] { "org/jboss/byteman/rule/exception/ExecuteException" }); mv.visitCode(); // rule.getEvent().interpret(this); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "getEvent", "()Lorg/jboss/byteman/rule/Event;"); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Event", "interpret", "(Lorg/jboss/byteman/rule/helper/HelperAdapter;)Ljava/lang/Object;"); mv.visitInsn(RETURN); mv.visitMaxs(2, 1); mv.visitEnd(); } { // create the test method // // private boolean test() mv = cw.visitMethod(ACC_PRIVATE, "test", "()Z", null, new String[] { "org/jboss/byteman/rule/exception/ExecuteException" }); mv.visitCode(); // {TOS} <== rule.getCondition().interpret(this); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "getCondition", "()Lorg/jboss/byteman/rule/Condition;"); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Condition", "interpret", "(Lorg/jboss/byteman/rule/helper/HelperAdapter;)Ljava/lang/Object;"); mv.visitTypeInsn(Opcodes.CHECKCAST, "java/lang/Boolean"); // unbox the returned Boolean mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Boolean", "booleanValue", "()Z"); // return {TOS} mv.visitInsn(IRETURN); mv.visitMaxs(2, 1); mv.visitEnd(); } { // create the fire method // // private void fire() mv = cw.visitMethod(ACC_PRIVATE, "fire", "()V", null, new String[] { "org/jboss/byteman/rule/exception/ExecuteException" }); mv.visitCode(); // rule.getAction().interpret(this); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, compiledHelperName, "rule", "Lorg/jboss/byteman/rule/Rule;"); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Rule", "getAction", "()Lorg/jboss/byteman/rule/Action;"); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKEVIRTUAL, "org/jboss/byteman/rule/Action", "interpret", "(Lorg/jboss/byteman/rule/helper/HelperAdapter;)Ljava/lang/Object;"); // return mv.visitInsn(RETURN); mv.visitMaxs(2, 1); mv.visitEnd(); } } cw.visitEnd(); return cw.toByteArray(); } private static int nextId = 0; private static synchronized int nextId() { return ++nextId; } /** * this is a classloader used to define classes from bytecode */ private static class ClassbyteClassLoader extends ClassLoader { ClassbyteClassLoader(ClassLoader cl) { super(cl); } public Class addClass(String name, byte[] bytes) throws ClassFormatError { Class cl = defineClass(name, bytes, 0, bytes.length); resolveClass(cl); return cl; } } /** * dynamically load and return a generated helper adapter classes using a custom classloader derived from the * trigger class's loader * @param triggerClassLoader the class loader of the trigger class which has been matched with this * helper class's rule * @param helperAdapterName the name of the helper adaptter class to be loaded * @param classBytes the byte array defining the class * @return */ public static Class<?> loadHelperAdapter(ClassLoader triggerClassLoader, String helperAdapterName, byte[] classBytes) { // create the helper class in a classloader derived from the trigger class // this allows the injected code to refer to the triggger class type and related // application types. the defalt helper will be accessible because it is loaded bby the // ootstrap loader. custom helpers need to be made avvailable to the applicattion either // by deployng them with it or by locating them in the JVM classpath. ClassbyteClassLoader loader = new ClassbyteClassLoader(triggerClassLoader); return loader.addClass(helperAdapterName, classBytes); } }