Implement RetransformClasses
This CL implements basic support for the RetransformClasses function
and callbacks of the ClassFileLoadHook.
We do not yet support calling the ClassFileLoadHook events on first
load of class.
Bug: 32369913
Bug: 31684920
Test: mma -j40 test-art-host
Change-Id: I7959474f03f9903cc6f10ae3c06d9fd531ec7957
diff --git a/runtime/openjdkjvmti/transform.cc b/runtime/openjdkjvmti/transform.cc
index f545125..2809cb6 100644
--- a/runtime/openjdkjvmti/transform.cc
+++ b/runtime/openjdkjvmti/transform.cc
@@ -38,6 +38,7 @@
#include "class_linker.h"
#include "dex_file.h"
#include "dex_file_types.h"
+#include "events-inl.h"
#include "gc_root-inl.h"
#include "globals.h"
#include "jni_env_ext-inl.h"
@@ -52,12 +53,76 @@
#include "scoped_thread_state_change-inl.h"
#include "stack.h"
#include "thread_list.h"
+#include "ti_redefine.h"
#include "transform.h"
#include "utf.h"
#include "utils/dex_cache_arrays_layout-inl.h"
namespace openjdkjvmti {
+jvmtiError Transformer::RetransformClassesDirect(
+ ArtJvmTiEnv* env,
+ art::Thread* self,
+ /*in-out*/std::vector<ArtClassDefinition>* definitions) {
+ for (ArtClassDefinition& def : *definitions) {
+ jint new_len = -1;
+ unsigned char* new_data = nullptr;
+ // Static casts are so that we get the right template initialization for the special event
+ // handling code required by the ClassFileLoadHooks.
+ gEventHandler.DispatchEvent(self,
+ ArtJvmtiEvent::kClassFileLoadHookRetransformable,
+ GetJniEnv(env),
+ static_cast<jclass>(def.klass),
+ static_cast<jobject>(def.loader),
+ static_cast<const char*>(def.name.c_str()),
+ static_cast<jobject>(def.protection_domain),
+ static_cast<jint>(def.dex_len),
+ static_cast<const unsigned char*>(def.dex_data.get()),
+ static_cast<jint*>(&new_len),
+ static_cast<unsigned char**>(&new_data));
+ def.SetNewDexData(env, new_len, new_data);
+ }
+ return OK;
+}
+
+jvmtiError Transformer::RetransformClasses(ArtJvmTiEnv* env,
+ art::Runtime* runtime,
+ art::Thread* self,
+ jint class_count,
+ const jclass* classes,
+ /*out*/std::string* error_msg) {
+ if (env == nullptr) {
+ *error_msg = "env was null!";
+ return ERR(INVALID_ENVIRONMENT);
+ } else if (class_count < 0) {
+ *error_msg = "class_count was less then 0";
+ return ERR(ILLEGAL_ARGUMENT);
+ } else if (class_count == 0) {
+ // We don't actually need to do anything. Just return OK.
+ return OK;
+ } else if (classes == nullptr) {
+ *error_msg = "null classes!";
+ return ERR(NULL_POINTER);
+ }
+ // A holder that will Deallocate all the class bytes buffers on destruction.
+ std::vector<ArtClassDefinition> definitions;
+ jvmtiError res = OK;
+ for (jint i = 0; i < class_count; i++) {
+ ArtClassDefinition def;
+ res = FillInTransformationData(env, classes[i], &def);
+ if (res != OK) {
+ return res;
+ }
+ definitions.push_back(std::move(def));
+ }
+ res = RetransformClassesDirect(env, self, &definitions);
+ if (res != OK) {
+ return res;
+ }
+ return Redefiner::RedefineClassesDirect(env, runtime, self, definitions, error_msg);
+}
+
+// TODO Move this somewhere else, ti_class?
jvmtiError GetClassLocation(ArtJvmTiEnv* env, jclass klass, /*out*/std::string* location) {
JNIEnv* jni_env = nullptr;
jint ret = env->art_vm->GetEnv(reinterpret_cast<void**>(&jni_env), JNI_VERSION_1_1);
@@ -73,42 +138,61 @@
return OK;
}
-// TODO Move this function somewhere more appropriate.
-// Gets the data surrounding the given class.
-jvmtiError GetTransformationData(ArtJvmTiEnv* env,
- jclass klass,
- /*out*/std::string* location,
- /*out*/JNIEnv** jni_env_ptr,
- /*out*/jobject* loader,
- /*out*/std::string* name,
- /*out*/jobject* protection_domain,
- /*out*/jint* data_len,
- /*out*/unsigned char** dex_data) {
- jint ret = env->art_vm->GetEnv(reinterpret_cast<void**>(jni_env_ptr), JNI_VERSION_1_1);
- if (ret != JNI_OK) {
- // TODO Different error might be better?
- return ERR(INTERNAL);
- }
- JNIEnv* jni_env = *jni_env_ptr;
- art::ScopedObjectAccess soa(jni_env);
- art::StackHandleScope<3> hs(art::Thread::Current());
- art::Handle<art::mirror::Class> hs_klass(hs.NewHandle(soa.Decode<art::mirror::Class>(klass)));
- *loader = soa.AddLocalReference<jobject>(hs_klass->GetClassLoader());
- *name = art::mirror::Class::ComputeName(hs_klass)->ToModifiedUtf8();
- // TODO is this always null?
- *protection_domain = nullptr;
- const art::DexFile& dex = hs_klass->GetDexFile();
- *location = dex.GetLocation();
- *data_len = static_cast<jint>(dex.Size());
- // TODO We should maybe change env->Allocate to allow us to mprotect this memory and stop writes.
- jvmtiError alloc_error = env->Allocate(*data_len, dex_data);
+// TODO Implement this for real once transformed dex data is actually saved.
+jvmtiError Transformer::GetDexDataForRetransformation(ArtJvmTiEnv* env,
+ art::Handle<art::mirror::Class> klass,
+ /*out*/jint* dex_data_len,
+ /*out*/unsigned char** dex_data) {
+ // TODO De-quicken the dex file before passing it to the agents.
+ LOG(WARNING) << "Dex file is not de-quickened yet! Quickened dex instructions might be present";
+ LOG(WARNING) << "Caching of initial dex data is not yet performed! Dex data might have been "
+ << "transformed by agent already";
+ const art::DexFile& dex = klass->GetDexFile();
+ *dex_data_len = static_cast<jint>(dex.Size());
+ unsigned char* new_dex_data = nullptr;
+ jvmtiError alloc_error = env->Allocate(*dex_data_len, &new_dex_data);
if (alloc_error != OK) {
return alloc_error;
}
// Copy the data into a temporary buffer.
- memcpy(reinterpret_cast<void*>(*dex_data),
- reinterpret_cast<const void*>(dex.Begin()),
- *data_len);
+ memcpy(reinterpret_cast<void*>(new_dex_data),
+ reinterpret_cast<const void*>(dex.Begin()),
+ *dex_data_len);
+ *dex_data = new_dex_data;
+ return OK;
+}
+
+// TODO Move this function somewhere more appropriate.
+// Gets the data surrounding the given class.
+// TODO Make this less magical.
+jvmtiError Transformer::FillInTransformationData(ArtJvmTiEnv* env,
+ jclass klass,
+ ArtClassDefinition* def) {
+ JNIEnv* jni_env = GetJniEnv(env);
+ if (jni_env == nullptr) {
+ // TODO Different error might be better?
+ return ERR(INTERNAL);
+ }
+ art::ScopedObjectAccess soa(jni_env);
+ art::StackHandleScope<3> hs(art::Thread::Current());
+ art::Handle<art::mirror::Class> hs_klass(hs.NewHandle(soa.Decode<art::mirror::Class>(klass)));
+ if (hs_klass.IsNull()) {
+ return ERR(INVALID_CLASS);
+ }
+ def->klass = klass;
+ def->loader = soa.AddLocalReference<jobject>(hs_klass->GetClassLoader());
+ def->name = art::mirror::Class::ComputeName(hs_klass)->ToModifiedUtf8();
+ // TODO is this always null?
+ def->protection_domain = nullptr;
+ if (def->dex_data.get() == nullptr) {
+ unsigned char* new_data;
+ jvmtiError res = GetDexDataForRetransformation(env, hs_klass, &def->dex_len, &new_data);
+ if (res == OK) {
+ def->dex_data = MakeJvmtiUniquePtr(env, new_data);
+ } else {
+ return res;
+ }
+ }
return OK;
}