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/runtime/openjdkjvmti/OpenjdkJvmTi.cc b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
index d3561c1..a1a2361 100644
--- a/runtime/openjdkjvmti/OpenjdkJvmTi.cc
+++ b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
@@ -29,15 +29,17 @@
* questions.
*/
+#include <string>
+#include <vector>
+
#include <jni.h>
+
#include "openjdkjvmti/jvmti.h"
#include "art_jvmti.h"
-#include "gc_root-inl.h"
-#include "globals.h"
#include "jni_env_ext-inl.h"
-#include "scoped_thread_state_change.h"
-#include "thread_list.h"
+#include "runtime.h"
+#include "transform.h"
// TODO Remove this at some point by annotating all the methods. It was put in to make the skeleton
// easier to create.
@@ -904,6 +906,66 @@
static jvmtiError GetJLocationFormat(jvmtiEnv* env, jvmtiJlocationFormat* format_ptr) {
return ERR(NOT_IMPLEMENTED);
}
+
+ // TODO Remove this once events are working.
+ static jvmtiError RetransformClassWithHook(jvmtiEnv* env,
+ jclass klass,
+ jvmtiEventClassFileLoadHook hook) {
+ std::vector<jclass> classes;
+ classes.push_back(klass);
+ return RetransformClassesWithHook(reinterpret_cast<ArtJvmTiEnv*>(env), classes, hook);
+ }
+
+ // TODO This will be called by the event handler for the art::ti Event Load Event
+ static jvmtiError RetransformClassesWithHook(ArtJvmTiEnv* env,
+ const std::vector<jclass>& classes,
+ jvmtiEventClassFileLoadHook hook) {
+ if (!IsValidEnv(env)) {
+ return ERR(INVALID_ENVIRONMENT);
+ }
+ for (jclass klass : classes) {
+ JNIEnv* jni_env = nullptr;
+ jobject loader = nullptr;
+ std::string name;
+ jobject protection_domain = nullptr;
+ jint data_len = 0;
+ unsigned char* dex_data = nullptr;
+ jvmtiError ret = OK;
+ std::string location;
+ if ((ret = GetTransformationData(env,
+ klass,
+ /*out*/&location,
+ /*out*/&jni_env,
+ /*out*/&loader,
+ /*out*/&name,
+ /*out*/&protection_domain,
+ /*out*/&data_len,
+ /*out*/&dex_data)) != OK) {
+ // TODO Do something more here? Maybe give log statements?
+ return ret;
+ }
+ jint new_data_len = 0;
+ unsigned char* new_dex_data = nullptr;
+ hook(env,
+ jni_env,
+ klass,
+ loader,
+ name.c_str(),
+ protection_domain,
+ data_len,
+ dex_data,
+ /*out*/&new_data_len,
+ /*out*/&new_dex_data);
+ // Check if anything actually changed.
+ if ((new_data_len != 0 || new_dex_data != nullptr) && new_dex_data != dex_data) {
+ MoveTransformedFileIntoRuntime(klass, std::move(location), new_data_len, new_dex_data);
+ env->Deallocate(new_dex_data);
+ }
+ // Deallocate the old dex data.
+ env->Deallocate(dex_data);
+ }
+ return OK;
+ }
};
static bool IsJvmtiVersion(jint version) {
@@ -942,7 +1004,10 @@
// The actual struct holding all of the entrypoints into the jvmti interface.
const jvmtiInterface_1 gJvmtiInterface = {
- nullptr, // reserved1
+ // SPECIAL FUNCTION: RetransformClassWithHook Is normally reserved1
+ // TODO Remove once we have events working.
+ reinterpret_cast<void*>(JvmtiFunctions::RetransformClassWithHook),
+ // nullptr, // reserved1
JvmtiFunctions::SetEventNotificationMode,
nullptr, // reserved3
JvmtiFunctions::GetAllThreads,