@Override
protected void onApply(CtBehavior behavior, Bytecode bytecode) throws BadBytecode {
bytecode = BytecodeTools.prepareMethodForBytecode(behavior, bytecode);
// loop through the opcodes and change any GT/GE opcodes to ICMPGT/ICMPGE
CodeIterator iterator = behavior.getMethodInfo().getCodeAttribute().iterator();
while (iterator.hasNext()) {
int index = iterator.next();
int opcode = iterator.byteAt(index);
switch (opcode) {
case Opcode.IFGT:
// overwrite the opcode
iterator.writeByte(Opcode.IF_ICMPGT, index);
// insert the method call
iterator.insertAt(index, bytecode.get());
behavior.getMethodInfo().getCodeAttribute().computeMaxStack();
break;
case Opcode.IFGE:
// overwrite the opcode
iterator.writeByte(Opcode.IF_ICMPGE, index);
// insert the method call
iterator.insertAt(index, bytecode.get());
behavior.getMethodInfo().getCodeAttribute().computeMaxStack();
break;
}
}
}
public static void rewriteFakeMethod(CodeIterator methodBody, String methodDescriptor) {
String ret = DescriptorUtils.getReturnType(methodDescriptor);
// if the return type is larger than one then it is not a primitive
// so it does not need to be boxed
if (ret.length() != 1) {
return;
}
byte ar = (byte) Opcode.ARETURN;
byte[] areturn = {ar};
// void methods are special
if (ret.equals("V")) {
while (methodBody.hasNext()) {
try {
int index = methodBody.next();
int opcode = methodBody.byteAt(index);
// replace a RETURN opcode with
// ACONST_NULL
// ARETURN
// to return a null value
if (opcode == Opcode.RETURN) {
Bytecode code = new Bytecode(methodBody.get().getConstPool());
code.add(Opcode.ACONST_NULL);
code.add(Opcode.ARETURN);
methodBody.insertAt(index, code.get());
}
} catch (BadBytecode e) {
throw new RuntimeException(e);
}
}
} else {
while (methodBody.hasNext()) {
try {
int index = methodBody.next();
int opcode = methodBody.byteAt(index);
switch (opcode) {
case Opcode.IRETURN:
case Opcode.LRETURN:
case Opcode.DRETURN:
case Opcode.FRETURN:
// write a NOP over the old return instruction
// insert the boxing code to get an object on the stack
Bytecode b = new Bytecode(methodBody.get().getConstPool());
Boxing.box(b, ret.charAt(0));
b.addOpcode(Opcode.ARETURN);
methodBody.insertAt(index, b.get());
}
} catch (BadBytecode e) {
throw new RuntimeException(e);
}
}
}
}
private void initExtraHarvest() {
try {
CtClass terraForming =
HookManager.getInstance()
.getClassPool()
.get("com.wurmonline.server.behaviours.Terraforming");
CtClass[] paramTypes = {
HookManager.getInstance().getClassPool().get("com.wurmonline.server.creatures.Creature"),
CtPrimitiveType.intType,
CtPrimitiveType.intType,
CtPrimitiveType.booleanType,
CtPrimitiveType.intType,
CtPrimitiveType.floatType,
HookManager.getInstance().getClassPool().get("com.wurmonline.server.items.Item")
};
CtMethod method =
terraForming.getMethod(
"harvest", Descriptor.ofMethod(CtPrimitiveType.booleanType, paramTypes));
MethodInfo methodInfo = method.getMethodInfo();
CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
CodeIterator codeIterator = codeAttribute.iterator();
LocalVariableAttribute attr =
(LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
int quantityIndex = -1;
for (int i = 0; i < attr.tableLength(); i++) {
if ("quantity".equals(attr.variableName(i))) {
quantityIndex = attr.index(i);
}
}
if (quantityIndex == -1) {
throw new HookException("Quantity variable can not be resolved");
}
while (codeIterator.hasNext()) {
int pos = codeIterator.next();
int op = codeIterator.byteAt(pos);
if (op == CodeIterator.ISTORE) {
int fieldRefIdx = codeIterator.byteAt(pos + 1);
if (quantityIndex == fieldRefIdx) {
Bytecode bytecode = new Bytecode(codeIterator.get().getConstPool());
bytecode.addIconst(extraHarvest);
bytecode.add(Bytecode.IADD);
codeIterator.insertAt(pos, bytecode.get());
break;
}
}
}
} catch (NotFoundException | BadBytecode e) {
throw new HookException(e);
}
}
@Override
public boolean transform(
ClassLoader loader,
String className,
Class<?> classBeingRedefined,
ProtectionDomain protectionDomain,
ClassFile file)
throws IllegalClassFormatException, BadBytecode {
/**
* Hack up the proxy factory so it stores the proxy ClassFile. We need this to regenerate
* proxies.
*/
if (file.getName().equals("org.jboss.weld.bean.proxy.ProxyFactory")) {
for (final MethodInfo method : (List<MethodInfo>) file.getMethods()) {
if (method.getName().equals("createProxyClass")) {
final MethodInvokationManipulator methodInvokationManipulator =
new MethodInvokationManipulator();
methodInvokationManipulator.replaceVirtualMethodInvokationWithStatic(
ClassLoader.class.getName(),
WeldProxyClassLoadingDelegate.class.getName(),
"loadClass",
"(Ljava/lang/String;)Ljava/lang/Class;",
"(Ljava/lang/ClassLoader;Ljava/lang/String;)Ljava/lang/Class;",
loader);
methodInvokationManipulator.replaceVirtualMethodInvokationWithStatic(
"org.jboss.weld.util.bytecode.ClassFileUtils",
WeldProxyClassLoadingDelegate.class.getName(),
"toClass",
"(Ljavassist/bytecode/ClassFile;Ljava/lang/ClassLoader;Ljava/security/ProtectionDomain;)Ljava/lang/Class;",
"(Ljavassist/bytecode/ClassFile;Ljava/lang/ClassLoader;Ljava/security/ProtectionDomain;)Ljava/lang/Class;",
loader);
HashSet<MethodInfo> modifiedMethods = new HashSet<MethodInfo>();
methodInvokationManipulator.transformClass(file, loader, true, modifiedMethods);
for (MethodInfo m : modifiedMethods) {
m.rebuildStackMap(ClassPool.getDefault());
}
return true;
} else if (method.getName().equals("<init>")) {
Integer beanArgument = null;
int count = 0;
for (final String paramType :
DescriptorUtils.descriptorStringToParameterArray(method.getDescriptor())) {
if (paramType.equals("javax/enterprise/inject/spi/Bean")) {
beanArgument = count;
break;
} else if (paramType.equals("D") || paramType.equals("J")) {
count += 2;
} else {
count++;
}
}
if (beanArgument == null) {
log.error(
"Constructor org.jboss.weld.bean.proxy.ProxyFactory.<init>"
+ method.getDescriptor()
+ " does not have a bean parameter, proxies produced by this factory will not be reloadable");
continue;
}
// similar to other tracked instances
// but we need a strong ref
Bytecode code = new Bytecode(file.getConstPool());
code.addAload(0);
code.addAload(beanArgument);
code.addInvokestatic(
WeldClassChangeAware.class.getName(),
"addProxyFactory",
"(Lorg/jboss/weld/bean/proxy/ProxyFactory;)V");
CodeIterator it = method.getCodeAttribute().iterator();
it.skipConstructor();
it.insert(code.get());
}
}
}
return false;
}
public boolean transformClass(ClassFile file, ClassLoader loader, boolean modifiableClass) {
Set<Integer> methodCallLocations = new HashSet<Integer>();
Integer newCallLocation = null;
Integer methodReflectionLocation = null;
Integer fakeCallRequiredLocation = null;
// first we need to scan the constant pool looking for
// CONSTANT_method_info_ref structures
ConstPool pool = file.getConstPool();
for (int i = 1; i < pool.getSize(); ++i) {
// we have a method call
if (pool.getTag(i) == ConstPool.CONST_Methodref) {
String className = pool.getMethodrefClassName(i);
String methodName = pool.getMethodrefName(i);
if (className.equals(Method.class.getName())) {
if (methodName.equals("invoke")) {
// store the location in the const pool of the method ref
methodCallLocations.add(i);
// we have found a method call
// if we have not already stored a reference to our new
// method in the const pool
if (newCallLocation == null) {
methodReflectionLocation =
pool.addClassInfo("org.fakereplace.reflection.MethodReflection");
int nt = pool.addNameAndTypeInfo("fakeCallRequired", "(Ljava/lang/reflect/Method;)Z");
fakeCallRequiredLocation = pool.addMethodrefInfo(methodReflectionLocation, nt);
newCallLocation = pool.addNameAndTypeInfo(METHOD_NAME, REPLACED_METHOD_DESCRIPTOR);
}
}
}
}
}
// this means we found an instance of the call, now we have to iterate
// through the methods and replace instances of the call
if (newCallLocation != null) {
List<MethodInfo> methods = file.getMethods();
for (MethodInfo m : methods) {
try {
// ignore abstract methods
if (m.getCodeAttribute() == null) {
continue;
}
CodeIterator it = m.getCodeAttribute().iterator();
while (it.hasNext()) {
// loop through the bytecode
int index = it.next();
int op = it.byteAt(index);
// if the bytecode is a method invocation
if (op == CodeIterator.INVOKEVIRTUAL) {
int val = it.s16bitAt(index + 1);
// if the method call is one of the methods we are
// replacing
if (methodCallLocations.contains(val)) {
Bytecode b = new Bytecode(file.getConstPool());
// our stack looks like Method, instance,params
// we need Method, instance, params , Method
b.add(Opcode.DUP_X2);
b.add(Opcode.POP);
b.add(Opcode.DUP_X2);
b.add(Opcode.POP);
b.add(Opcode.DUP_X2);
b.addInvokestatic(
methodReflectionLocation, "fakeCallRequired", "(Ljava/lang/reflect/Method;)Z");
b.add(Opcode.IFEQ);
JumpMarker performRealCall = JumpUtils.addJumpInstruction(b);
// now perform the fake call
b.addInvokestatic(methodReflectionLocation, "invoke", REPLACED_METHOD_DESCRIPTOR);
b.add(Opcode.GOTO);
JumpMarker finish = JumpUtils.addJumpInstruction(b);
performRealCall.mark();
b.addInvokevirtual(Method.class.getName(), METHOD_NAME, METHOD_DESCRIPTOR);
finish.mark();
it.writeByte(CodeIterator.NOP, index);
it.writeByte(CodeIterator.NOP, index + 1);
it.writeByte(CodeIterator.NOP, index + 2);
it.insert(b.get());
}
}
}
m.getCodeAttribute().computeMaxStack();
} catch (Exception e) {
log.error("Bad byte code transforming " + file.getName());
e.printStackTrace();
}
}
return true;
} else {
return false;
}
}
