/* 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 "ti_class_definition.h"
#include "base/array_slice.h"
#include "base/logging.h"
#include "class_linker-inl.h"
#include "class_root.h"
#include "dex/dex_file.h"
#include "fixed_up_dex_file.h"
#include "handle.h"
#include "handle_scope-inl.h"
#include "mirror/class-inl.h"
#include "mirror/class_ext-inl.h"
#include "mirror/object-inl.h"
#include "reflection.h"
#include "thread.h"
namespace openjdkjvmti {
void ArtClassDefinition::InitializeMemory() const {
DCHECK(art::MemMap::kCanReplaceMapping);
VLOG(signals) << "Initializing de-quickened memory for dex file of " << name_;
CHECK(dex_data_mmap_.IsValid());
CHECK(temp_mmap_.IsValid());
CHECK_EQ(dex_data_mmap_.GetProtect(), PROT_NONE);
CHECK_EQ(temp_mmap_.GetProtect(), PROT_READ | PROT_WRITE);
std::string desc = std::string("L") + name_ + ";";
std::unique_ptr<FixedUpDexFile>
fixed_dex_file(FixedUpDexFile::Create(*initial_dex_file_unquickened_, desc.c_str()));
CHECK(fixed_dex_file.get() != nullptr);
CHECK_LE(fixed_dex_file->Size(), temp_mmap_.Size());
CHECK_EQ(temp_mmap_.Size(), dex_data_mmap_.Size());
// Copy the data to the temp mmap.
memcpy(temp_mmap_.Begin(), fixed_dex_file->Begin(), fixed_dex_file->Size());
// Move the mmap atomically.
art::MemMap source;
source.swap(temp_mmap_);
std::string error;
CHECK(dex_data_mmap_.ReplaceWith(&source, &error)) << "Failed to replace mmap for "
<< name_ << " because " << error;
CHECK(dex_data_mmap_.Protect(PROT_READ));
}
bool ArtClassDefinition::IsModified() const {
// RedefineClasses calls always are 'modified' since they need to change the current_dex_file of
// the class.
if (redefined_) {
return true;
}
// Check to see if any change has taken place.
if (current_dex_file_.data() == dex_data_.data()) {
// no change at all.
return false;
}
// The dex_data_ was never touched by the agents.
if (dex_data_mmap_.IsValid() && dex_data_mmap_.GetProtect() == PROT_NONE) {
if (current_dex_file_.data() == dex_data_mmap_.Begin()) {
// the dex_data_ looks like it changed (not equal to current_dex_file_) but we never
// initialized the dex_data_mmap_. This means the new_dex_data was filled in without looking
// at the initial dex_data_.
return true;
} else if (dex_data_.data() == dex_data_mmap_.Begin()) {
// The dex file used to have modifications but they were not added again.
return true;
} else {
// It's not clear what happened. It's possible that the agent got the current dex file data
// from some other source so we need to initialize everything to see if it is the same.
VLOG(signals) << "Lazy dex file for " << name_ << " was never touched but the dex_data_ is "
<< "changed! Need to initialize the memory to see if anything changed";
InitializeMemory();
}
}
// We can definitely read current_dex_file_ and dex_file_ without causing page faults.
// Check if the dex file we want to set is the same as the current one.
// Unfortunately we need to do this check even if no modifications have been done since it could
// be that agents were removed in the mean-time so we still have a different dex file. The dex
// checksum means this is likely to be fairly fast.
return current_dex_file_.size() != dex_data_.size() ||
memcmp(current_dex_file_.data(), dex_data_.data(), current_dex_file_.size()) != 0;
}
jvmtiError ArtClassDefinition::InitCommon(art::Thread* self, jclass klass) {
art::ScopedObjectAccess soa(self);
art::ObjPtr<art::mirror::Class> m_klass(soa.Decode<art::mirror::Class>(klass));
if (m_klass.IsNull()) {
return ERR(INVALID_CLASS);
}
initialized_ = true;
klass_ = klass;
loader_ = soa.AddLocalReference<jobject>(m_klass->GetClassLoader());
std::string descriptor_store;
std::string descriptor(m_klass->GetDescriptor(&descriptor_store));
name_ = descriptor.substr(1, descriptor.size() - 2);
// Android doesn't really have protection domains.
protection_domain_ = nullptr;
return OK;
}
static void DequickenDexFile(const art::DexFile* dex_file,
const char* descriptor,
/*out*/std::vector<unsigned char>* dex_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
std::unique_ptr<FixedUpDexFile> fixed_dex_file(
FixedUpDexFile::Create(*dex_file, descriptor));
dex_data->resize(fixed_dex_file->Size());
memcpy(dex_data->data(), fixed_dex_file->Begin(), fixed_dex_file->Size());
}
// Gets the data surrounding the given class.
static void GetDexDataForRetransformation(art::Handle<art::mirror::Class> klass,
/*out*/std::vector<unsigned char>* dex_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::StackHandleScope<3> hs(art::Thread::Current());
art::Handle<art::mirror::ClassExt> ext(hs.NewHandle(klass->GetExtData()));
const art::DexFile* dex_file = nullptr;
if (!ext.IsNull()) {
art::Handle<art::mirror::Object> orig_dex(hs.NewHandle(ext->GetOriginalDexFile()));
if (!orig_dex.IsNull()) {
if (orig_dex->IsArrayInstance()) {
DCHECK(orig_dex->GetClass()->GetComponentType()->IsPrimitiveByte());
art::Handle<art::mirror::ByteArray> orig_dex_bytes(hs.NewHandle(orig_dex->AsByteArray()));
dex_data->resize(orig_dex_bytes->GetLength());
memcpy(dex_data->data(), orig_dex_bytes->GetData(), dex_data->size());
return;
} else if (orig_dex->IsDexCache()) {
dex_file = orig_dex->AsDexCache()->GetDexFile();
} else {
DCHECK(orig_dex->GetClass()->DescriptorEquals("Ljava/lang/Long;"))
<< "Expected java/lang/Long but found object of type "
<< orig_dex->GetClass()->PrettyClass();
art::ObjPtr<art::mirror::Class> prim_long_class(
art::GetClassRoot(art::ClassRoot::kPrimitiveLong));
art::JValue val;
if (!art::UnboxPrimitiveForResult(orig_dex.Get(), prim_long_class, &val)) {
// This should never happen.
LOG(FATAL) << "Unable to unbox a primitive long value!";
}
dex_file = reinterpret_cast<const art::DexFile*>(static_cast<uintptr_t>(val.GetJ()));
}
}
}
if (dex_file == nullptr) {
dex_file = &klass->GetDexFile();
}
std::string storage;
DequickenDexFile(dex_file, klass->GetDescriptor(&storage), dex_data);
}
static bool DexNeedsDequickening(art::Handle<art::mirror::Class> klass,
/*out*/ bool* from_class_ext)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::ObjPtr<art::mirror::ClassExt> ext(klass->GetExtData());
if (ext.IsNull()) {
// We don't seem to have ever been redefined so be conservative and say we need de-quickening.
*from_class_ext = false;
return true;
}
art::ObjPtr<art::mirror::Object> orig_dex(ext->GetOriginalDexFile());
if (orig_dex.IsNull()) {
// We don't seem to have ever been redefined so be conservative and say we need de-quickening.
*from_class_ext = false;
return true;
} else if (!orig_dex->IsArrayInstance()) {
// We were redefined but the original is held in a dex-cache or dex file. This means that the
// original dex file is the one from the disk, which might be quickened.
DCHECK(orig_dex->IsDexCache() || orig_dex->GetClass()->DescriptorEquals("Ljava/lang/Long;"));
*from_class_ext = true;
return true;
} else {
// An array instance means the original-dex-file is from a redefineClasses which cannot have any
// quickening, so it's fine to use directly.
DCHECK(orig_dex->GetClass()->GetComponentType()->IsPrimitiveByte());
*from_class_ext = true;
return false;
}
}
static const art::DexFile* GetQuickenedDexFile(art::Handle<art::mirror::Class> klass)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::ObjPtr<art::mirror::ClassExt> ext(klass->GetExtData());
if (ext.IsNull() || ext->GetOriginalDexFile() == nullptr) {
return &klass->GetDexFile();
}
art::ObjPtr<art::mirror::Object> orig_dex(ext->GetOriginalDexFile());
DCHECK(!orig_dex->IsArrayInstance());
if (orig_dex->IsDexCache()) {
return orig_dex->AsDexCache()->GetDexFile();
}
DCHECK(orig_dex->GetClass()->DescriptorEquals("Ljava/lang/Long;"))
<< "Expected java/lang/Long but found object of type "
<< orig_dex->GetClass()->PrettyClass();
art::ObjPtr<art::mirror::Class> prim_long_class(
art::GetClassRoot(art::ClassRoot::kPrimitiveLong));
art::JValue val;
if (!art::UnboxPrimitiveForResult(orig_dex.Ptr(), prim_long_class, &val)) {
LOG(FATAL) << "Unable to unwrap a long value!";
}
return reinterpret_cast<const art::DexFile*>(static_cast<uintptr_t>(val.GetJ()));
}
template<typename GetOriginalDexFile>
void ArtClassDefinition::InitWithDex(GetOriginalDexFile get_original,
const art::DexFile* quick_dex) {
art::Thread* self = art::Thread::Current();
DCHECK(quick_dex != nullptr);
if (art::MemMap::kCanReplaceMapping && kEnableOnDemandDexDequicken) {
size_t dequick_size = quick_dex->GetDequickenedSize();
std::string mmap_name("anon-mmap-for-redefine: ");
mmap_name += name_;
std::string error;
dex_data_mmap_ = art::MemMap::MapAnonymous(mmap_name.c_str(),
dequick_size,
PROT_NONE,
/*low_4gb=*/ false,
&error);
mmap_name += "-TEMP";
temp_mmap_ = art::MemMap::MapAnonymous(mmap_name.c_str(),
dequick_size,
PROT_READ | PROT_WRITE,
/*low_4gb=*/ false,
&error);
if (UNLIKELY(dex_data_mmap_.IsValid() && temp_mmap_.IsValid())) {
// Need to save the initial dexfile so we don't need to search for it in the fault-handler.
initial_dex_file_unquickened_ = quick_dex;
dex_data_ = art::ArrayRef<const unsigned char>(dex_data_mmap_.Begin(),
dex_data_mmap_.Size());
if (from_class_ext_) {
// We got initial from class_ext so the current one must have undergone redefinition so no
// cdex or quickening stuff.
// We can only do this if it's not a first load.
DCHECK(klass_ != nullptr);
const art::DexFile& cur_dex = self->DecodeJObject(klass_)->AsClass()->GetDexFile();
current_dex_file_ = art::ArrayRef<const unsigned char>(cur_dex.Begin(), cur_dex.Size());
} else {
// This class hasn't been redefined before. The dequickened current data is the same as the
// dex_data_mmap_ when it's filled it. We don't need to copy anything because the mmap will
// not be cleared until after everything is done.
current_dex_file_ = art::ArrayRef<const unsigned char>(dex_data_mmap_.Begin(),
dequick_size);
}
return;
}
}
dex_data_mmap_.Reset();
temp_mmap_.Reset();
// Failed to mmap a large enough area (or on-demand dequickening was disabled). This is
// unfortunate. Since currently the size is just a guess though we might as well try to do it
// manually.
get_original(/*out*/&dex_data_memory_);
dex_data_ = art::ArrayRef<const unsigned char>(dex_data_memory_);
if (from_class_ext_) {
// We got initial from class_ext so the current one must have undergone redefinition so no
// cdex or quickening stuff.
// We can only do this if it's not a first load.
DCHECK(klass_ != nullptr);
const art::DexFile& cur_dex = self->DecodeJObject(klass_)->AsClass()->GetDexFile();
current_dex_file_ = art::ArrayRef<const unsigned char>(cur_dex.Begin(), cur_dex.Size());
} else {
// No redefinition must have ever happened so the (dequickened) cur_dex is the same as the
// initial dex_data. We need to copy it into another buffer to keep it around if we have a
// real redefinition.
current_dex_memory_.resize(dex_data_.size());
memcpy(current_dex_memory_.data(), dex_data_.data(), current_dex_memory_.size());
current_dex_file_ = art::ArrayRef<const unsigned char>(current_dex_memory_);
}
}
jvmtiError ArtClassDefinition::Init(art::Thread* self, jclass klass) {
jvmtiError res = InitCommon(self, klass);
if (res != OK) {
return res;
}
art::ScopedObjectAccess soa(self);
art::StackHandleScope<1> hs(self);
art::Handle<art::mirror::Class> m_klass(hs.NewHandle(self->DecodeJObject(klass)->AsClass()));
if (!DexNeedsDequickening(m_klass, &from_class_ext_)) {
// We don't need to do any dequickening. We want to copy the data just so we don't need to deal
// with the GC moving it around.
art::ObjPtr<art::mirror::ByteArray> orig_dex(
m_klass->GetExtData()->GetOriginalDexFile()->AsByteArray());
dex_data_memory_.resize(orig_dex->GetLength());
memcpy(dex_data_memory_.data(), orig_dex->GetData(), dex_data_memory_.size());
dex_data_ = art::ArrayRef<const unsigned char>(dex_data_memory_);
// Since we are here we must not have any quickened instructions since we were redefined.
const art::DexFile& cur_dex = m_klass->GetDexFile();
DCHECK(from_class_ext_);
current_dex_file_ = art::ArrayRef<const unsigned char>(cur_dex.Begin(), cur_dex.Size());
return OK;
}
// We need to dequicken stuff. This is often super slow (10's of ms). Instead we will do it
// dynamically.
const art::DexFile* quick_dex = GetQuickenedDexFile(m_klass);
auto get_original = [&](/*out*/std::vector<unsigned char>* dex_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
GetDexDataForRetransformation(m_klass, dex_data);
};
InitWithDex(get_original, quick_dex);
return OK;
}
jvmtiError ArtClassDefinition::Init(art::Thread* self, const jvmtiClassDefinition& def) {
jvmtiError res = InitCommon(self, def.klass);
if (res != OK) {
return res;
}
// We are being directly redefined.
redefined_ = true;
current_dex_file_ = art::ArrayRef<const unsigned char>(def.class_bytes, def.class_byte_count);
dex_data_ = art::ArrayRef<const unsigned char>(def.class_bytes, def.class_byte_count);
return OK;
}
void ArtClassDefinition::InitFirstLoad(const char* descriptor,
art::Handle<art::mirror::ClassLoader> klass_loader,
const art::DexFile& dex_file) {
art::Thread* self = art::Thread::Current();
art::ScopedObjectAccess soa(self);
initialized_ = true;
// No Class
klass_ = nullptr;
loader_ = soa.AddLocalReference<jobject>(klass_loader.Get());
std::string descriptor_str(descriptor);
name_ = descriptor_str.substr(1, descriptor_str.size() - 2);
// Android doesn't really have protection domains.
protection_domain_ = nullptr;
auto get_original = [&](/*out*/std::vector<unsigned char>* dex_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
DequickenDexFile(&dex_file, descriptor, dex_data);
};
InitWithDex(get_original, &dex_file);
}
} // namespace openjdkjvmti