Get a basic modification of dex file working
This allows the modification of a single classes methods through
transformation. One must ensure that the provided dex file only
contains one function and does not add or remove any methods or fields
and does not change the inheritance hierarchy in any way. The provided
dex file must verify and there must be no frames of the old code
present on any thread. These constraints are not checked or verified.
Breaking them might cause undefined behavior in all parts of the
runtime. Code that has been inlined in any way might not be replaced.
This feature is extremely experimental.
Bug: 31455788
Test: ./test/run-test --host 902-hello-transformation
Change-Id: I35133d24f6cdafdd2af9dc9863e15ba8493fc50e
diff --git a/test/902-hello-transformation/transform.cc b/test/902-hello-transformation/transform.cc
new file mode 100644
index 0000000..e0d623e
--- /dev/null
+++ b/test/902-hello-transformation/transform.cc
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include <iostream>
+#include <pthread.h>
+#include <stdio.h>
+#include <vector>
+
+#include "art_method-inl.h"
+#include "base/logging.h"
+#include "jni.h"
+#include "openjdkjvmti/jvmti.h"
+#include "utils.h"
+
+namespace art {
+namespace Test902HelloTransformation {
+
+static bool RuntimeIsJvm = false;
+
+jvmtiEnv* jvmti_env;
+bool IsJVM() {
+ return RuntimeIsJvm;
+}
+
+// base64 encoded class/dex file for
+//
+// class Transform {
+// public void sayHi() {
+// System.out.println("Goodbye");
+// }
+// }
+const char* class_file_base64 =
+ "yv66vgAAADQAHAoABgAOCQAPABAIABEKABIAEwcAFAcAFQEABjxpbml0PgEAAygpVgEABENvZGUB"
+ "AA9MaW5lTnVtYmVyVGFibGUBAAVzYXlIaQEAClNvdXJjZUZpbGUBAA5UcmFuc2Zvcm0uamF2YQwA"
+ "BwAIBwAWDAAXABgBAAdHb29kYnllBwAZDAAaABsBAAlUcmFuc2Zvcm0BABBqYXZhL2xhbmcvT2Jq"
+ "ZWN0AQAQamF2YS9sYW5nL1N5c3RlbQEAA291dAEAFUxqYXZhL2lvL1ByaW50U3RyZWFtOwEAE2ph"
+ "dmEvaW8vUHJpbnRTdHJlYW0BAAdwcmludGxuAQAVKExqYXZhL2xhbmcvU3RyaW5nOylWACAABQAG"
+ "AAAAAAACAAAABwAIAAEACQAAAB0AAQABAAAABSq3AAGxAAAAAQAKAAAABgABAAAAEQABAAsACAAB"
+ "AAkAAAAlAAIAAQAAAAmyAAISA7YABLEAAAABAAoAAAAKAAIAAAATAAgAFAABAAwAAAACAA0=";
+
+const char* dex_file_base64 =
+ "ZGV4CjAzNQCLXSBQ5FiS3f16krSYZFF8xYZtFVp0GRXMAgAAcAAAAHhWNBIAAAAAAAAAACwCAAAO"
+ "AAAAcAAAAAYAAACoAAAAAgAAAMAAAAABAAAA2AAAAAQAAADgAAAAAQAAAAABAACsAQAAIAEAAGIB"
+ "AABqAQAAcwEAAIABAACXAQAAqwEAAL8BAADTAQAA4wEAAOYBAADqAQAA/gEAAAMCAAAMAgAAAgAA"
+ "AAMAAAAEAAAABQAAAAYAAAAIAAAACAAAAAUAAAAAAAAACQAAAAUAAABcAQAABAABAAsAAAAAAAAA"
+ "AAAAAAAAAAANAAAAAQABAAwAAAACAAAAAAAAAAAAAAAAAAAAAgAAAAAAAAAHAAAAAAAAAB4CAAAA"
+ "AAAAAQABAAEAAAATAgAABAAAAHAQAwAAAA4AAwABAAIAAAAYAgAACQAAAGIAAAAbAQEAAABuIAIA"
+ "EAAOAAAAAQAAAAMABjxpbml0PgAHR29vZGJ5ZQALTFRyYW5zZm9ybTsAFUxqYXZhL2lvL1ByaW50"
+ "U3RyZWFtOwASTGphdmEvbGFuZy9PYmplY3Q7ABJMamF2YS9sYW5nL1N0cmluZzsAEkxqYXZhL2xh"
+ "bmcvU3lzdGVtOwAOVHJhbnNmb3JtLmphdmEAAVYAAlZMABJlbWl0dGVyOiBqYWNrLTMuMzYAA291"
+ "dAAHcHJpbnRsbgAFc2F5SGkAEQAHDgATAAcOhQAAAAEBAICABKACAQG4Ag0AAAAAAAAAAQAAAAAA"
+ "AAABAAAADgAAAHAAAAACAAAABgAAAKgAAAADAAAAAgAAAMAAAAAEAAAAAQAAANgAAAAFAAAABAAA"
+ "AOAAAAAGAAAAAQAAAAABAAABIAAAAgAAACABAAABEAAAAQAAAFwBAAACIAAADgAAAGIBAAADIAAA"
+ "AgAAABMCAAAAIAAAAQAAAB4CAAAAEAAAAQAAACwCAAA=";
+
+static void JNICALL transformationHook(jvmtiEnv *jvmtienv,
+ JNIEnv* jni_env ATTRIBUTE_UNUSED,
+ jclass class_being_redefined ATTRIBUTE_UNUSED,
+ jobject loader ATTRIBUTE_UNUSED,
+ const char* name,
+ jobject protection_domain ATTRIBUTE_UNUSED,
+ jint class_data_len ATTRIBUTE_UNUSED,
+ const unsigned char* class_data ATTRIBUTE_UNUSED,
+ jint* new_class_data_len,
+ unsigned char** new_class_data) {
+ if (strcmp("Transform", name)) {
+ return;
+ }
+ printf("modifying class '%s'\n", name);
+ bool is_jvm = IsJVM();
+ size_t decode_len = 0;
+ unsigned char* new_data;
+ std::unique_ptr<uint8_t[]> file_data(
+ DecodeBase64((is_jvm) ? class_file_base64 : dex_file_base64, &decode_len));
+ jvmtiError ret = JVMTI_ERROR_NONE;
+ if ((ret = jvmtienv->Allocate(static_cast<jlong>(decode_len), &new_data)) != JVMTI_ERROR_NONE) {
+ printf("Unable to allocate buffer!\n");
+ return;
+ }
+ memcpy(new_data, file_data.get(), decode_len);
+ *new_class_data_len = static_cast<jint>(decode_len);
+ *new_class_data = new_data;
+ return;
+}
+
+using RetransformWithHookFunction = jvmtiError (*)(jvmtiEnv*, jclass, jvmtiEventClassFileLoadHook);
+static void DoClassTransformation(jvmtiEnv* jvmtienv, JNIEnv* jnienv, jclass target) {
+ if (IsJVM()) {
+ UNUSED(jnienv);
+ jvmtienv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr);
+ jvmtiError ret = jvmtienv->RetransformClasses(1, &target);
+ if (ret != JVMTI_ERROR_NONE) {
+ char* err;
+ jvmtienv->GetErrorName(ret, &err);
+ printf("Error transforming: %s\n", err);
+ }
+ } else {
+ RetransformWithHookFunction f =
+ reinterpret_cast<RetransformWithHookFunction>(jvmtienv->functions->reserved1);
+ if (f(jvmtienv, target, transformationHook) != JVMTI_ERROR_NONE) {
+ printf("Failed to tranform class!");
+ return;
+ }
+ }
+}
+
+extern "C" JNIEXPORT void JNICALL Java_Main_doClassTransformation(JNIEnv* env,
+ jclass,
+ jclass target) {
+ JavaVM* vm;
+ if (env->GetJavaVM(&vm)) {
+ printf("Unable to get javaVM!\n");
+ return;
+ }
+ DoClassTransformation(jvmti_env, env, target);
+}
+
+// Don't do anything
+jint OnLoad(JavaVM* vm,
+ char* options,
+ void* reserved ATTRIBUTE_UNUSED) {
+ jvmtiCapabilities caps;
+ RuntimeIsJvm = (strcmp("jvm", options) == 0);
+ if (vm->GetEnv(reinterpret_cast<void**>(&jvmti_env), JVMTI_VERSION_1_0)) {
+ printf("Unable to get jvmti env!\n");
+ return 1;
+ }
+ if (IsJVM()) {
+ jvmti_env->GetPotentialCapabilities(&caps);
+ jvmti_env->AddCapabilities(&caps);
+ jvmtiEventCallbacks cbs;
+ memset(&cbs, 0, sizeof(cbs));
+ cbs.ClassFileLoadHook = transformationHook;
+ jvmti_env->SetEventCallbacks(&cbs, sizeof(jvmtiEventCallbacks));
+ }
+ return 0;
+}
+
+} // namespace Test902HelloTransformation
+} // namespace art
+