ART: Add OnLoad system classloader search support
Add support for extension of the system classloader search path
during the OnLoad phase. Add test.
Bug: 34359699
Test: m test-art-host-run-test-936-search-onload
Change-Id: Ie0a5b4bb77999dfae87f955dde40b73ffe053b8e
diff --git a/runtime/openjdkjvmti/ti_search.cc b/runtime/openjdkjvmti/ti_search.cc
index 913d2b6..df80f85 100644
--- a/runtime/openjdkjvmti/ti_search.cc
+++ b/runtime/openjdkjvmti/ti_search.cc
@@ -34,15 +34,177 @@
#include "jni.h"
#include "art_jvmti.h"
+#include "base/enums.h"
#include "base/macros.h"
#include "class_linker.h"
#include "dex_file.h"
+#include "jni_internal.h"
+#include "mirror/class-inl.h"
+#include "mirror/object.h"
+#include "mirror/string.h"
+#include "obj_ptr-inl.h"
#include "runtime.h"
+#include "runtime_callbacks.h"
#include "scoped_thread_state_change-inl.h"
#include "ScopedLocalRef.h"
+#include "ti_phase.h"
+#include "thread-inl.h"
+#include "thread_list.h"
namespace openjdkjvmti {
+static std::vector<std::string> gSystemOnloadSegments;
+
+static art::ObjPtr<art::mirror::Object> GetSystemProperties(art::Thread* self,
+ art::ClassLinker* class_linker)
+ REQUIRES_SHARED(art::Locks::mutator_lock_) {
+ art::ObjPtr<art::mirror::Class> system_class =
+ class_linker->LookupClass(self, "Ljava/lang/System;", nullptr);
+ DCHECK(system_class != nullptr);
+ DCHECK(system_class->IsInitialized());
+
+ art::ArtField* props_field =
+ system_class->FindDeclaredStaticField("props", "Ljava/util/Properties;");
+ DCHECK(props_field != nullptr);
+
+ art::ObjPtr<art::mirror::Object> props_obj = props_field->GetObject(system_class);
+ DCHECK(props_obj != nullptr);
+
+ return props_obj;
+}
+
+static void Update() REQUIRES_SHARED(art::Locks::mutator_lock_) {
+ if (gSystemOnloadSegments.empty()) {
+ return;
+ }
+
+ // In the on-load phase we have to modify java.class.path to influence the system classloader.
+ // As this is an unmodifiable system property, we have to access the "defaults" field.
+ art::ClassLinker* class_linker = art::Runtime::Current()->GetClassLinker();
+ DCHECK(class_linker != nullptr);
+ art::Thread* self = art::Thread::Current();
+
+ // Prepare: collect classes, fields and methods.
+ art::ObjPtr<art::mirror::Class> properties_class =
+ class_linker->LookupClass(self, "Ljava/util/Properties;", nullptr);
+ DCHECK(properties_class != nullptr);
+
+ ScopedLocalRef<jobject> defaults_jobj(self->GetJniEnv(), nullptr);
+ {
+ art::ObjPtr<art::mirror::Object> props_obj = GetSystemProperties(self, class_linker);
+
+ art::ArtField* defaults_field =
+ properties_class->FindDeclaredInstanceField("defaults", "Ljava/util/Properties;");
+ DCHECK(defaults_field != nullptr);
+
+ art::ObjPtr<art::mirror::Object> defaults_obj = defaults_field->GetObject(props_obj);
+ DCHECK(defaults_obj != nullptr);
+ defaults_jobj.reset(self->GetJniEnv()->AddLocalReference<jobject>(defaults_obj));
+ }
+
+ art::ArtMethod* get_property =
+ properties_class->FindDeclaredVirtualMethod(
+ "getProperty",
+ "(Ljava/lang/String;)Ljava/lang/String;",
+ art::kRuntimePointerSize);
+ DCHECK(get_property != nullptr);
+ art::ArtMethod* set_property =
+ properties_class->FindDeclaredVirtualMethod(
+ "setProperty",
+ "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;",
+ art::kRuntimePointerSize);
+ DCHECK(set_property != nullptr);
+
+ // This is an allocation. Do this late to avoid the need for handles.
+ ScopedLocalRef<jobject> cp_jobj(self->GetJniEnv(), nullptr);
+ {
+ art::ObjPtr<art::mirror::Object> cp_key =
+ art::mirror::String::AllocFromModifiedUtf8(self, "java.class.path");
+ if (cp_key == nullptr) {
+ self->AssertPendingOOMException();
+ self->ClearException();
+ return;
+ }
+ cp_jobj.reset(self->GetJniEnv()->AddLocalReference<jobject>(cp_key));
+ }
+
+ // OK, now get the current value.
+ std::string str_value;
+ {
+ ScopedLocalRef<jobject> old_value(self->GetJniEnv(),
+ self->GetJniEnv()->CallObjectMethod(
+ defaults_jobj.get(),
+ art::jni::EncodeArtMethod(get_property),
+ cp_jobj.get()));
+ DCHECK(old_value.get() != nullptr);
+
+ str_value = self->DecodeJObject(old_value.get())->AsString()->ToModifiedUtf8();
+ self->GetJniEnv()->DeleteLocalRef(old_value.release());
+ }
+
+ // Update the value by appending the new segments.
+ for (const std::string& segment : gSystemOnloadSegments) {
+ if (!str_value.empty()) {
+ str_value += ":";
+ }
+ str_value += segment;
+ }
+ gSystemOnloadSegments.clear();
+
+ // Create the new value object.
+ ScopedLocalRef<jobject> new_val_jobj(self->GetJniEnv(), nullptr);
+ {
+ art::ObjPtr<art::mirror::Object> new_value =
+ art::mirror::String::AllocFromModifiedUtf8(self, str_value.c_str());
+ if (new_value == nullptr) {
+ self->AssertPendingOOMException();
+ self->ClearException();
+ return;
+ }
+
+ new_val_jobj.reset(self->GetJniEnv()->AddLocalReference<jobject>(new_value));
+ }
+
+ // Write to the defaults.
+ ScopedLocalRef<jobject> res_obj(self->GetJniEnv(),
+ self->GetJniEnv()->CallObjectMethod(defaults_jobj.get(),
+ art::jni::EncodeArtMethod(set_property),
+ cp_jobj.get(),
+ new_val_jobj.get()));
+ if (self->IsExceptionPending()) {
+ self->ClearException();
+ return;
+ }
+}
+
+struct SearchCallback : public art::RuntimePhaseCallback {
+ void NextRuntimePhase(RuntimePhase phase) OVERRIDE REQUIRES_SHARED(art::Locks::mutator_lock_) {
+ if (phase == RuntimePhase::kStart) {
+ // It's time to update the system properties.
+ Update();
+ }
+ }
+};
+
+static SearchCallback gSearchCallback;
+
+void SearchUtil::Register() {
+ art::Runtime* runtime = art::Runtime::Current();
+
+ art::ScopedThreadStateChange stsc(art::Thread::Current(),
+ art::ThreadState::kWaitingForDebuggerToAttach);
+ art::ScopedSuspendAll ssa("Add search callback");
+ runtime->GetRuntimeCallbacks()->AddRuntimePhaseCallback(&gSearchCallback);
+}
+
+void SearchUtil::Unregister() {
+ art::ScopedThreadStateChange stsc(art::Thread::Current(),
+ art::ThreadState::kWaitingForDebuggerToAttach);
+ art::ScopedSuspendAll ssa("Remove search callback");
+ art::Runtime* runtime = art::Runtime::Current();
+ runtime->GetRuntimeCallbacks()->RemoveRuntimePhaseCallback(&gSearchCallback);
+}
+
jvmtiError SearchUtil::AddToBootstrapClassLoaderSearch(jvmtiEnv* env ATTRIBUTE_UNUSED,
const char* segment) {
art::Runtime* current = art::Runtime::Current();
@@ -78,14 +240,21 @@
return ERR(NULL_POINTER);
}
- art::Runtime* current = art::Runtime::Current();
- if (current == nullptr) {
+ jvmtiPhase phase = PhaseUtil::GetPhaseUnchecked();
+
+ if (phase == jvmtiPhase::JVMTI_PHASE_ONLOAD) {
+ // We could try and see whether it is a valid path. We could also try to allocate Java
+ // objects to avoid later OOME.
+ gSystemOnloadSegments.push_back(segment);
+ return ERR(NONE);
+ } else if (phase != jvmtiPhase::JVMTI_PHASE_LIVE) {
return ERR(WRONG_PHASE);
}
- jobject sys_class_loader = current->GetSystemClassLoader();
+
+ jobject sys_class_loader = art::Runtime::Current()->GetSystemClassLoader();
if (sys_class_loader == nullptr) {
- // TODO: Support classpath change in OnLoad.
- return ERR(WRONG_PHASE);
+ // This is unexpected.
+ return ERR(INTERNAL);
}
// We'll use BaseDexClassLoader.addDexPath, as it takes care of array resizing etc. As a downside,