/* Copyright (C) 2016 The Android Open Source Project
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This file implements interfaces from the file jvmti.h. This implementation
* is licensed under the same terms as the file jvmti.h. The
* copyright and license information for the file jvmti.h follows.
*
* Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
#include <stddef.h>
#include <sys/types.h>
#include <unordered_map>
#include <unordered_set>
#include "transform.h"
#include "art_method.h"
#include "base/array_ref.h"
#include "base/globals.h"
#include "base/logging.h"
#include "base/mem_map.h"
#include "class_linker.h"
#include "dex/dex_file.h"
#include "dex/dex_file_types.h"
#include "dex/utf.h"
#include "events-inl.h"
#include "fault_handler.h"
#include "gc_root-inl.h"
#include "handle_scope-inl.h"
#include "jni/jni_env_ext-inl.h"
#include "jvalue.h"
#include "jvmti.h"
#include "linear_alloc.h"
#include "mirror/array.h"
#include "mirror/class-inl.h"
#include "mirror/class_ext.h"
#include "mirror/class_loader-inl.h"
#include "mirror/string-inl.h"
#include "oat_file.h"
#include "scoped_thread_state_change-inl.h"
#include "stack.h"
#include "thread_list.h"
#include "ti_redefine.h"
#include "transform.h"
#include "utils/dex_cache_arrays_layout-inl.h"
namespace openjdkjvmti {
// A FaultHandler that will deal with initializing ClassDefinitions when they are actually needed.
class TransformationFaultHandler final : public art::FaultHandler {
public:
explicit TransformationFaultHandler(art::FaultManager* manager)
: art::FaultHandler(manager),
uninitialized_class_definitions_lock_("JVMTI Initialized class definitions lock",
art::LockLevel::kSignalHandlingLock),
class_definition_initialized_cond_("JVMTI Initialized class definitions condition",
uninitialized_class_definitions_lock_) {
manager->AddHandler(this, /* generated_code= */ false);
}
~TransformationFaultHandler() {
art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
uninitialized_class_definitions_.clear();
}
bool Action(int sig, siginfo_t* siginfo, void* context ATTRIBUTE_UNUSED) override {
DCHECK_EQ(sig, SIGSEGV);
art::Thread* self = art::Thread::Current();
if (UNLIKELY(uninitialized_class_definitions_lock_.IsExclusiveHeld(self))) {
if (self != nullptr) {
LOG(FATAL) << "Recursive call into Transformation fault handler!";
UNREACHABLE();
} else {
LOG(ERROR) << "Possible deadlock due to recursive signal delivery of segv.";
}
}
uintptr_t ptr = reinterpret_cast<uintptr_t>(siginfo->si_addr);
ArtClassDefinition* res = nullptr;
{
// NB Technically using a mutex and condition variables here is non-posix compliant but
// everything should be fine since both glibc and bionic implementations of mutexs and
// condition variables work fine so long as the thread was not interrupted during a
// lock/unlock (which it wasn't) on all architectures we care about.
art::MutexLock mu(self, uninitialized_class_definitions_lock_);
auto it = std::find_if(uninitialized_class_definitions_.begin(),
uninitialized_class_definitions_.end(),
[&](const auto op) { return op->ContainsAddress(ptr); });
if (it != uninitialized_class_definitions_.end()) {
res = *it;
// Remove the class definition.
uninitialized_class_definitions_.erase(it);
// Put it in the initializing list
initializing_class_definitions_.push_back(res);
} else {
// Wait for the ptr to be initialized (if it is currently initializing).
while (DefinitionIsInitializing(ptr)) {
WaitForClassInitializationToFinish();
}
// Return true (continue with user code) if we find that the definition has been
// initialized. Return false (continue on to next signal handler) if the definition is not
// initialized or found.
return std::find_if(initialized_class_definitions_.begin(),
initialized_class_definitions_.end(),
[&](const auto op) { return op->ContainsAddress(ptr); }) !=
initialized_class_definitions_.end();
}
}
if (LIKELY(self != nullptr)) {
CHECK_EQ(self->GetState(), art::ThreadState::kNative)
<< "Transformation fault handler occurred outside of native mode";
}
VLOG(signals) << "Lazy initialization of dex file for transformation of " << res->GetName()
<< " during SEGV";
res->InitializeMemory();
{
art::MutexLock mu(self, uninitialized_class_definitions_lock_);
// Move to initialized state and notify waiters.
initializing_class_definitions_.erase(std::find(initializing_class_definitions_.begin(),
initializing_class_definitions_.end(),
res));
initialized_class_definitions_.push_back(res);
class_definition_initialized_cond_.Broadcast(self);
}
return true;
}
void RemoveDefinition(ArtClassDefinition* def) REQUIRES(!uninitialized_class_definitions_lock_) {
art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
auto it = std::find(uninitialized_class_definitions_.begin(),
uninitialized_class_definitions_.end(),
def);
if (it != uninitialized_class_definitions_.end()) {
uninitialized_class_definitions_.erase(it);
return;
}
while (std::find(initializing_class_definitions_.begin(),
initializing_class_definitions_.end(),
def) != initializing_class_definitions_.end()) {
WaitForClassInitializationToFinish();
}
it = std::find(initialized_class_definitions_.begin(),
initialized_class_definitions_.end(),
def);
CHECK(it != initialized_class_definitions_.end()) << "Could not find class definition for "
<< def->GetName();
initialized_class_definitions_.erase(it);
}
void AddArtDefinition(ArtClassDefinition* def) REQUIRES(!uninitialized_class_definitions_lock_) {
DCHECK(def->IsLazyDefinition());
art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
uninitialized_class_definitions_.push_back(def);
}
private:
bool DefinitionIsInitializing(uintptr_t ptr) REQUIRES(uninitialized_class_definitions_lock_) {
return std::find_if(initializing_class_definitions_.begin(),
initializing_class_definitions_.end(),
[&](const auto op) { return op->ContainsAddress(ptr); }) !=
initializing_class_definitions_.end();
}
void WaitForClassInitializationToFinish() REQUIRES(uninitialized_class_definitions_lock_) {
class_definition_initialized_cond_.Wait(art::Thread::Current());
}
art::Mutex uninitialized_class_definitions_lock_ ACQUIRED_BEFORE(art::Locks::abort_lock_);
art::ConditionVariable class_definition_initialized_cond_
GUARDED_BY(uninitialized_class_definitions_lock_);
// A list of the class definitions that have a non-readable map.
std::vector<ArtClassDefinition*> uninitialized_class_definitions_
GUARDED_BY(uninitialized_class_definitions_lock_);
// A list of class definitions that are currently undergoing unquickening. Threads should wait
// until the definition is no longer in this before returning.
std::vector<ArtClassDefinition*> initializing_class_definitions_
GUARDED_BY(uninitialized_class_definitions_lock_);
// A list of class definitions that are already unquickened. Threads should immediately return if
// it is here.
std::vector<ArtClassDefinition*> initialized_class_definitions_
GUARDED_BY(uninitialized_class_definitions_lock_);
};
static TransformationFaultHandler* gTransformFaultHandler = nullptr;
void Transformer::Setup() {
// Although we create this the fault handler is actually owned by the 'art::fault_manager' which
// will take care of destroying it.
if (art::MemMap::kCanReplaceMapping && ArtClassDefinition::kEnableOnDemandDexDequicken) {
gTransformFaultHandler = new TransformationFaultHandler(&art::fault_manager);
}
}
// Simple helper to add and remove the class definition from the fault handler.
class ScopedDefinitionHandler {
public:
explicit ScopedDefinitionHandler(ArtClassDefinition* def)
: def_(def), is_lazy_(def_->IsLazyDefinition()) {
if (is_lazy_) {
gTransformFaultHandler->AddArtDefinition(def_);
}
}
~ScopedDefinitionHandler() {
if (is_lazy_) {
gTransformFaultHandler->RemoveDefinition(def_);
}
}
private:
ArtClassDefinition* def_;
bool is_lazy_;
};
// Initialize templates.
template
void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookNonRetransformable>(
EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
template
void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookRetransformable>(
EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
template<ArtJvmtiEvent kEvent>
void Transformer::TransformSingleClassDirect(EventHandler* event_handler,
art::Thread* self,
/*in-out*/ArtClassDefinition* def) {
static_assert(kEvent == ArtJvmtiEvent::kClassFileLoadHookNonRetransformable ||
kEvent == ArtJvmtiEvent::kClassFileLoadHookRetransformable,
"bad event type");
// We don't want to do transitions between calling the event and setting the new data so change to
// native state early. This also avoids any problems that the FaultHandler might have in
// determining if an access to the dex_data is from generated code or not.
art::ScopedThreadStateChange stsc(self, art::ThreadState::kNative);
ScopedDefinitionHandler handler(def);
jint new_len = -1;
unsigned char* new_data = nullptr;
art::ArrayRef<const unsigned char> dex_data = def->GetDexData();
event_handler->DispatchEvent<kEvent>(
self,
static_cast<JNIEnv*>(self->GetJniEnv()),
def->GetClass(),
def->GetLoader(),
def->GetName().c_str(),
def->GetProtectionDomain(),
static_cast<jint>(dex_data.size()),
dex_data.data(),
/*out*/&new_len,
/*out*/&new_data);
def->SetNewDexData(new_len, new_data);
}
jvmtiError Transformer::RetransformClassesDirect(
EventHandler* event_handler,
art::Thread* self,
/*in-out*/std::vector<ArtClassDefinition>* definitions) {
for (ArtClassDefinition& def : *definitions) {
TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookRetransformable>(event_handler,
self,
&def);
}
return OK;
}
jvmtiError Transformer::RetransformClasses(ArtJvmTiEnv* env,
EventHandler* event_handler,
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++) {
res = Redefiner::GetClassRedefinitionError(classes[i], error_msg);
if (res != OK) {
return res;
}
ArtClassDefinition def;
res = def.Init(self, classes[i]);
if (res != OK) {
return res;
}
definitions.push_back(std::move(def));
}
res = RetransformClassesDirect(event_handler, 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);
if (ret != JNI_OK) {
// TODO Different error might be better?
return ERR(INTERNAL);
}
art::ScopedObjectAccess soa(jni_env);
art::StackHandleScope<1> hs(art::Thread::Current());
art::Handle<art::mirror::Class> hs_klass(hs.NewHandle(soa.Decode<art::mirror::Class>(klass)));
const art::DexFile& dex = hs_klass->GetDexFile();
*location = dex.GetLocation();
return OK;
}
} // namespace openjdkjvmti