static void de_robv_android_xposed_XposedBridge_hookMethodNative(JNIEnv* env,
jclass clazz, jobject reflectedMethodIndirect,
jobject declaredClassIndirect, jint slot,
jobject additionalInfoIndirect) {
// Usage errors?
if (declaredClassIndirect == NULL || reflectedMethodIndirect == NULL) {
dvmThrowIllegalArgumentException(
"method and declaredClass must not be null");
return;
}
// Find the internal representation of the method
ClassObject* declaredClass = (ClassObject*) dvmDecodeIndirectRef(
dvmThreadSelf(), declaredClassIndirect);
Method* method = dvmSlotToMethod(declaredClass, slot);
if (method == NULL) {
dvmThrowNoSuchMethodError(
"could not get internal representation for method");
return;
}
if (xposedIsHooked(method)) {
ALOGD("Hook: Ignored! [%s] [%s]\n", declaredClass->descriptor, method->name);
// already hooked
return;
}
else {
ALOGD("Hook: [%s] [%s]\n", declaredClass->descriptor, method->name);
}
// Save a copy of the original method and other hook info
XposedHookInfo* hookInfo = (XposedHookInfo*) calloc(1,
sizeof(XposedHookInfo));
memcpy(hookInfo, method, sizeof(hookInfo->originalMethodStruct));
hookInfo->reflectedMethod = dvmDecodeIndirectRef(dvmThreadSelf(),
env->NewGlobalRef(reflectedMethodIndirect));
hookInfo->additionalInfo = dvmDecodeIndirectRef(dvmThreadSelf(),
env->NewGlobalRef(additionalInfoIndirect));
// Replace method with our own code
SET_METHOD_FLAG(method, ACC_NATIVE);
method->nativeFunc = &xposedCallHandler;
method->insns = (const u2*) hookInfo;
method->registersSize = method->insSize;
method->outsSize = 0;
if (PTR_gDvmJit != NULL) {
// reset JIT cache
MEMBER_VAL(PTR_gDvmJit, DvmJitGlobals, codeCacheFull) = true;
}
}
// simplified copy of Method.invokeNative, but calls the original (non-hooked) method and has no access checks
// used when a method has been hooked
static void de_robv_android_xposed_XposedBridge_invokeOriginalMethodNative(const u4* args, JValue* pResult,
const Method* method, ::Thread* self) {
Method* meth = (Method*) args[1];
if (meth == NULL) {
meth = dvmGetMethodFromReflectObj((Object*) args[0]);
if (xposedIsHooked(meth)) {
meth = (Method*) meth->insns;
}
}
ArrayObject* params = (ArrayObject*) args[2];
ClassObject* returnType = (ClassObject*) args[3];
Object* thisObject = (Object*) args[4]; // null for static methods
ArrayObject* argList = (ArrayObject*) args[5];
// invoke the method
pResult->l = dvmInvokeMethod(thisObject, meth, argList, params, returnType, true);
return;
}
static void xposedCallHandler(const u4* args, JValue* pResult,
const Method* method, ::Thread* self) {
if (!xposedIsHooked(method)) {
dvmThrowNoSuchMethodError(
"could not find Xposed original method - how did you even get here?");
return;
}
XposedHookInfo* hookInfo = (XposedHookInfo*) method->insns;
Method* original = (Method*) hookInfo;
Object* originalReflected = hookInfo->reflectedMethod;
Object* additionalInfo = hookInfo->additionalInfo;
// convert/box arguments
const char* desc = &method->shorty[1]; // [0] is the return type.
Object* thisObject = NULL;
size_t srcIndex = 0;
size_t dstIndex = 0;
// for non-static methods determine the "this" pointer
if (!dvmIsStaticMethod(original)) {
thisObject = (Object*) args[0];
srcIndex++;
}
ArrayObject* argsArray = dvmAllocArrayByClass(objectArrayClass,
strlen(method->shorty) - 1, ALLOC_DEFAULT);
if (argsArray == NULL) {
return;
}
while (*desc != '\0') {
char descChar = *(desc++);
JValue value;
Object* obj;
switch (descChar) {
case 'Z':
case 'C':
case 'F':
case 'B':
case 'S':
case 'I':
value.i = args[srcIndex++];
obj = (Object*) dvmBoxPrimitive(value,
dvmFindPrimitiveClass(descChar));
dvmReleaseTrackedAlloc(obj, self);
break;
case 'D':
case 'J':
value.j = dvmGetArgLong(args, srcIndex);
srcIndex += 2;
obj = (Object*) dvmBoxPrimitive(value,
dvmFindPrimitiveClass(descChar));
dvmReleaseTrackedAlloc(obj, self);
break;
case '[':
case 'L':
obj = (Object*) args[srcIndex++];
break;
default:
ALOGE("Unknown method signature description character: %c\n",
descChar);
obj = NULL;
srcIndex++;
}
xposedSetObjectArrayElement(argsArray, dstIndex++, obj);
}
// call the Java handler function
JValue result;
dvmCallMethod(self, xposedHandleHookedMethod, NULL, &result,
originalReflected, (int) original, additionalInfo, thisObject,
argsArray);
dvmReleaseTrackedAlloc(argsArray, self);
// exceptions are thrown to the caller
if (dvmCheckException(self)) {
return;
}
// return result with proper type
ClassObject* returnType = dvmGetBoxedReturnType(method);
if (returnType->primitiveType == PRIM_VOID) {
// ignored
} else if (result.l == NULL) {
if (dvmIsPrimitiveClass(returnType)) {
dvmThrowNullPointerException("null result when primitive expected");
}
pResult->l = NULL;
} else {
if (!dvmUnboxPrimitive(result.l, returnType, pResult)) {
dvmThrowClassCastException(result.l->clazz, returnType);
}
}
}