runtime/vdex_file.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2016 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "vdex_file.h"

 #include <sys/mman.h>  // For the PROT_* and MAP_* constants.

 #include <memory>

 #include "base/bit_utils.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/unix_file/fd_file.h"
 #include "dex_file.h"
 #include "dex_to_dex_decompiler.h"

 namespace art {

 constexpr uint8_t VdexFile::Header::kVdexInvalidMagic[4];
 constexpr uint8_t VdexFile::Header::kVdexMagic[4];
 constexpr uint8_t VdexFile::Header::kVdexVersion[4];

 bool VdexFile::Header::IsMagicValid() const {
   return (memcmp(magic_, kVdexMagic, sizeof(kVdexMagic)) == 0);
 }

 bool VdexFile::Header::IsVersionValid() const {
   return (memcmp(version_, kVdexVersion, sizeof(kVdexVersion)) == 0);
 }

 VdexFile::Header::Header(uint32_t number_of_dex_files,
                          uint32_t dex_size,
                          uint32_t verifier_deps_size,
                          uint32_t quickening_info_size)
     : number_of_dex_files_(number_of_dex_files),
       dex_size_(dex_size),
       verifier_deps_size_(verifier_deps_size),
       quickening_info_size_(quickening_info_size) {
   memcpy(magic_, kVdexMagic, sizeof(kVdexMagic));
   memcpy(version_, kVdexVersion, sizeof(kVdexVersion));
   DCHECK(IsMagicValid());
   DCHECK(IsVersionValid());
 }

 std::unique_ptr<VdexFile> VdexFile::Open(const std::string& vdex_filename,
                                          bool writable,
                                          bool low_4gb,
                                          bool unquicken,
                                          std::string* error_msg) {
   if (!OS::FileExists(vdex_filename.c_str())) {
     *error_msg = "File " + vdex_filename + " does not exist.";
     return nullptr;
   }

   std::unique_ptr<File> vdex_file;
   if (writable) {
     vdex_file.reset(OS::OpenFileReadWrite(vdex_filename.c_str()));
   } else {
     vdex_file.reset(OS::OpenFileForReading(vdex_filename.c_str()));
   }
   if (vdex_file == nullptr) {
     *error_msg = "Could not open file " + vdex_filename +
                  (writable ? " for read/write" : "for reading");
     return nullptr;
   }

   int64_t vdex_length = vdex_file->GetLength();
   if (vdex_length == -1) {
     *error_msg = "Could not read the length of file " + vdex_filename;
     return nullptr;
   }

   return Open(vdex_file->Fd(), vdex_length, vdex_filename, writable, low_4gb, unquicken, error_msg);
 }

 std::unique_ptr<VdexFile> VdexFile::Open(int file_fd,
                                          size_t vdex_length,
                                          const std::string& vdex_filename,
                                          bool writable,
                                          bool low_4gb,
                                          bool unquicken,
                                          std::string* error_msg) {
   std::unique_ptr<MemMap> mmap(MemMap::MapFile(
       vdex_length,
       (writable || unquicken) ? PROT_READ | PROT_WRITE : PROT_READ,
       unquicken ? MAP_PRIVATE : MAP_SHARED,
       file_fd,
       0 /* start offset */,
       low_4gb,
       vdex_filename.c_str(),
       error_msg));
   if (mmap == nullptr) {
     *error_msg = "Failed to mmap file " + vdex_filename + " : " + *error_msg;
     return nullptr;
   }

   std::unique_ptr<VdexFile> vdex(new VdexFile(mmap.release()));
   if (!vdex->IsValid()) {
     *error_msg = "Vdex file is not valid";
     return nullptr;
   }

   if (unquicken) {
     std::vector<std::unique_ptr<const DexFile>> unique_ptr_dex_files;
     if (!vdex->OpenAllDexFiles(&unique_ptr_dex_files, error_msg)) {
       return nullptr;
     }
     Unquicken(MakeNonOwningPointerVector(unique_ptr_dex_files), vdex->GetQuickeningInfo());
     // Update the quickening info size to pretend there isn't any.
     reinterpret_cast<Header*>(vdex->mmap_->Begin())->quickening_info_size_ = 0;
   }

   *error_msg = "Success";
   return vdex;
 }

 const uint8_t* VdexFile::GetNextDexFileData(const uint8_t* cursor) const {
   DCHECK(cursor == nullptr || (cursor > Begin() && cursor <= End()));
   if (cursor == nullptr) {
     // Beginning of the iteration, return the first dex file if there is one.
     return HasDexSection() ? DexBegin() : nullptr;
   } else {
     // Fetch the next dex file. Return null if there is none.
     const uint8_t* data = cursor + reinterpret_cast<const DexFile::Header*>(cursor)->file_size_;
     // Dex files are required to be 4 byte aligned. the OatWriter makes sure they are, see
     // OatWriter::SeekToDexFiles.
     data = AlignUp(data, 4);
     return (data == DexEnd()) ? nullptr : data;
   }
 }

 bool VdexFile::OpenAllDexFiles(std::vector<std::unique_ptr<const DexFile>>* dex_files,
                                std::string* error_msg) {
   size_t i = 0;
   for (const uint8_t* dex_file_start = GetNextDexFileData(nullptr);
        dex_file_start != nullptr;
        dex_file_start = GetNextDexFileData(dex_file_start), ++i) {
     size_t size = reinterpret_cast<const DexFile::Header*>(dex_file_start)->file_size_;
     // TODO: Supply the location information for a vdex file.
     static constexpr char kVdexLocation[] = "";
     std::string location = DexFile::GetMultiDexLocation(i, kVdexLocation);
     std::unique_ptr<const DexFile> dex(DexFile::Open(dex_file_start,
                                                      size,
                                                      location,
                                                      GetLocationChecksum(i),
                                                      nullptr /*oat_dex_file*/,
                                                      false /*verify*/,
                                                      false /*verify_checksum*/,
                                                      error_msg));
     if (dex == nullptr) {
       return false;
     }
     dex_files->push_back(std::move(dex));
   }
   return true;
 }

 // Utility class to easily iterate over the quickening data.
 class QuickeningInfoIterator {
  public:
   QuickeningInfoIterator(uint32_t dex_file_index,
                          uint32_t number_of_dex_files,
                          const ArrayRef<const uint8_t>& quickening_info)
       : quickening_info_(quickening_info) {
     const unaligned_uint32_t* dex_file_indices = reinterpret_cast<const unaligned_uint32_t*>(
             quickening_info.data() +
             quickening_info.size() -
             number_of_dex_files * sizeof(uint32_t));
     current_code_item_end_ = (dex_file_index == number_of_dex_files - 1)
         ? dex_file_indices
         : reinterpret_cast<const unaligned_uint32_t*>(
               quickening_info_.data() + dex_file_indices[dex_file_index + 1]);
     current_code_item_ptr_ = reinterpret_cast<const uint32_t*>(
         quickening_info_.data() + dex_file_indices[dex_file_index]);
   }

   bool Done() const {
     return current_code_item_ptr_ == current_code_item_end_;
   }

   void Advance() {
     current_code_item_ptr_ += 2;
   }

   uint32_t GetCurrentCodeItemOffset() const {
     return current_code_item_ptr_[0];
   }

   const ArrayRef<const uint8_t> GetCurrentQuickeningInfo() const {
     return ArrayRef<const uint8_t>(
         // Add sizeof(uint32_t) to remove the length from the data pointer.
         quickening_info_.data() + current_code_item_ptr_[1] + sizeof(uint32_t),
         *reinterpret_cast<const unaligned_uint32_t*>(
             quickening_info_.data() + current_code_item_ptr_[1]));
   }

  private:
   typedef __attribute__((__aligned__(1))) uint32_t unaligned_uint32_t;
   const ArrayRef<const uint8_t>& quickening_info_;
   const unaligned_uint32_t* current_code_item_ptr_;
   const unaligned_uint32_t* current_code_item_end_;

   DISALLOW_COPY_AND_ASSIGN(QuickeningInfoIterator);
 };

 void VdexFile::Unquicken(const std::vector<const DexFile*>& dex_files,
                          const ArrayRef<const uint8_t>& quickening_info) {
   if (quickening_info.size() == 0) {
     // Bail early if there is no quickening info.
     return;
   }
   // We do not decompile a RETURN_VOID_NO_BARRIER into a RETURN_VOID, as the quickening
   // optimization does not depend on the boot image (the optimization relies on not
   // having final fields in a class, which does not change for an app).
   constexpr bool kDecompileReturnInstruction = false;
   for (uint32_t i = 0; i < dex_files.size(); ++i) {
     for (QuickeningInfoIterator it(i, dex_files.size(), quickening_info);
          !it.Done();
          it.Advance()) {
       optimizer::ArtDecompileDEX(
           *dex_files[i]->GetCodeItem(it.GetCurrentCodeItemOffset()),
           it.GetCurrentQuickeningInfo(),
           kDecompileReturnInstruction);
     }
   }
 }

 static constexpr uint32_t kNoDexFile = -1;

 uint32_t VdexFile::GetDexFileIndex(const DexFile& dex_file) const {
   uint32_t dex_index = 0;
   for (const uint8_t* dex_file_start = GetNextDexFileData(nullptr);
        dex_file_start != dex_file.Begin();
        dex_file_start = GetNextDexFileData(dex_file_start)) {
     if (dex_file_start == nullptr) {
       return kNoDexFile;
     }
     dex_index++;
   }
   return dex_index;
 }

 void VdexFile::FullyUnquickenDexFile(const DexFile& target_dex_file,
                                      const DexFile& original_dex_file) const {
   uint32_t dex_index = GetDexFileIndex(original_dex_file);
   if (dex_index == kNoDexFile) {
     return;
   }

   constexpr bool kDecompileReturnInstruction = true;
   QuickeningInfoIterator it(dex_index, GetHeader().GetNumberOfDexFiles(), GetQuickeningInfo());
   // Iterate over the class definitions. Even if there is no quickening info,
   // we want to unquicken RETURN_VOID_NO_BARRIER instruction.
   for (uint32_t i = 0; i < target_dex_file.NumClassDefs(); ++i) {
     const DexFile::ClassDef& class_def = target_dex_file.GetClassDef(i);
     const uint8_t* class_data = target_dex_file.GetClassData(class_def);
     if (class_data != nullptr) {
       for (ClassDataItemIterator class_it(target_dex_file, class_data);
            class_it.HasNext();
            class_it.Next()) {
         if (class_it.IsAtMethod() && class_it.GetMethodCodeItem() != nullptr) {
           uint32_t offset = class_it.GetMethodCodeItemOffset();
           if (!it.Done() && offset == it.GetCurrentCodeItemOffset()) {
             optimizer::ArtDecompileDEX(
                 *class_it.GetMethodCodeItem(),
                 it.GetCurrentQuickeningInfo(),
                 kDecompileReturnInstruction);
             it.Advance();
           } else {
             optimizer::ArtDecompileDEX(*class_it.GetMethodCodeItem(),
                                        ArrayRef<const uint8_t>(nullptr, 0),
                                        kDecompileReturnInstruction);
           }
         }
       }
     }
   }
 }

 const uint8_t* VdexFile::GetQuickenedInfoOf(const DexFile& dex_file,
                                             uint32_t code_item_offset) const {
   if (GetQuickeningInfo().size() == 0) {
     // Bail early if there is no quickening info.
     return nullptr;
   }

   uint32_t dex_index = GetDexFileIndex(dex_file);
   if (dex_index == kNoDexFile) {
     return nullptr;
   }

   for (QuickeningInfoIterator it(dex_index, GetHeader().GetNumberOfDexFiles(), GetQuickeningInfo());
        !it.Done();
        it.Advance()) {
     if (code_item_offset == it.GetCurrentCodeItemOffset()) {
       return it.GetCurrentQuickeningInfo().data();
     }
   }
   return nullptr;
 }

 }  // namespace art
	/*
	* Copyright (C) 2016 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "vdex_file.h"

	#include <sys/mman.h> // For the PROT_* and MAP_* constants.

	#include <memory>

	#include "base/bit_utils.h"
	#include "base/logging.h"
	#include "base/stl_util.h"
	#include "base/unix_file/fd_file.h"
	#include "dex_file.h"
	#include "dex_to_dex_decompiler.h"

	namespace art {

	constexpr uint8_t VdexFile::Header::kVdexInvalidMagic[4];
	constexpr uint8_t VdexFile::Header::kVdexMagic[4];
	constexpr uint8_t VdexFile::Header::kVdexVersion[4];

	bool VdexFile::Header::IsMagicValid() const {
	return (memcmp(magic_, kVdexMagic, sizeof(kVdexMagic)) == 0);
	}

	bool VdexFile::Header::IsVersionValid() const {
	return (memcmp(version_, kVdexVersion, sizeof(kVdexVersion)) == 0);
	}

	VdexFile::Header::Header(uint32_t number_of_dex_files,
	uint32_t dex_size,
	uint32_t verifier_deps_size,
	uint32_t quickening_info_size)
	: number_of_dex_files_(number_of_dex_files),
	dex_size_(dex_size),
	verifier_deps_size_(verifier_deps_size),
	quickening_info_size_(quickening_info_size) {
	memcpy(magic_, kVdexMagic, sizeof(kVdexMagic));
	memcpy(version_, kVdexVersion, sizeof(kVdexVersion));
	DCHECK(IsMagicValid());
	DCHECK(IsVersionValid());
	}

	std::unique_ptr<VdexFile> VdexFile::Open(const std::string& vdex_filename,
	bool writable,
	bool low_4gb,
	bool unquicken,
	std::string* error_msg) {
	if (!OS::FileExists(vdex_filename.c_str())) {
	*error_msg = "File " + vdex_filename + " does not exist.";
	return nullptr;
	}

	std::unique_ptr<File> vdex_file;
	if (writable) {
	vdex_file.reset(OS::OpenFileReadWrite(vdex_filename.c_str()));
	} else {
	vdex_file.reset(OS::OpenFileForReading(vdex_filename.c_str()));
	}
	if (vdex_file == nullptr) {
	*error_msg = "Could not open file " + vdex_filename +
	(writable ? " for read/write" : "for reading");
	return nullptr;
	}

	int64_t vdex_length = vdex_file->GetLength();
	if (vdex_length == -1) {
	*error_msg = "Could not read the length of file " + vdex_filename;
	return nullptr;
	}

	return Open(vdex_file->Fd(), vdex_length, vdex_filename, writable, low_4gb, unquicken, error_msg);
	}

	std::unique_ptr<VdexFile> VdexFile::Open(int file_fd,
	size_t vdex_length,
	const std::string& vdex_filename,
	bool writable,
	bool low_4gb,
	bool unquicken,
	std::string* error_msg) {
	std::unique_ptr<MemMap> mmap(MemMap::MapFile(
	vdex_length,
	(writable \|\| unquicken) ? PROT_READ \| PROT_WRITE : PROT_READ,
	unquicken ? MAP_PRIVATE : MAP_SHARED,
	file_fd,
	0 /* start offset */,
	low_4gb,
	vdex_filename.c_str(),
	error_msg));
	if (mmap == nullptr) {
	error_msg = "Failed to mmap file " + vdex_filename + " : " + error_msg;
	return nullptr;
	}

	std::unique_ptr<VdexFile> vdex(new VdexFile(mmap.release()));
	if (!vdex->IsValid()) {
	*error_msg = "Vdex file is not valid";
	return nullptr;
	}

	if (unquicken) {
	std::vector<std::unique_ptr<const DexFile>> unique_ptr_dex_files;
	if (!vdex->OpenAllDexFiles(&unique_ptr_dex_files, error_msg)) {
	return nullptr;
	}
	Unquicken(MakeNonOwningPointerVector(unique_ptr_dex_files), vdex->GetQuickeningInfo());
	// Update the quickening info size to pretend there isn't any.
	reinterpret_cast<Header*>(vdex->mmap_->Begin())->quickening_info_size_ = 0;
	}

	*error_msg = "Success";
	return vdex;
	}

	const uint8_t* VdexFile::GetNextDexFileData(const uint8_t* cursor) const {
	DCHECK(cursor == nullptr \|\| (cursor > Begin() && cursor <= End()));
	if (cursor == nullptr) {
	// Beginning of the iteration, return the first dex file if there is one.
	return HasDexSection() ? DexBegin() : nullptr;
	} else {
	// Fetch the next dex file. Return null if there is none.
	const uint8_t* data = cursor + reinterpret_cast<const DexFile::Header*>(cursor)->file_size_;
	// Dex files are required to be 4 byte aligned. the OatWriter makes sure they are, see
	// OatWriter::SeekToDexFiles.
	data = AlignUp(data, 4);
	return (data == DexEnd()) ? nullptr : data;
	}
	}

	bool VdexFile::OpenAllDexFiles(std::vector<std::unique_ptr<const DexFile>>* dex_files,
	std::string* error_msg) {
	size_t i = 0;
	for (const uint8_t* dex_file_start = GetNextDexFileData(nullptr);
	dex_file_start != nullptr;
	dex_file_start = GetNextDexFileData(dex_file_start), ++i) {
	size_t size = reinterpret_cast<const DexFile::Header*>(dex_file_start)->file_size_;
	// TODO: Supply the location information for a vdex file.
	static constexpr char kVdexLocation[] = "";
	std::string location = DexFile::GetMultiDexLocation(i, kVdexLocation);
	std::unique_ptr<const DexFile> dex(DexFile::Open(dex_file_start,
	size,
	location,
	GetLocationChecksum(i),
	nullptr /oat_dex_file/,
	false /verify/,
	false /verify_checksum/,
	error_msg));
	if (dex == nullptr) {
	return false;
	}
	dex_files->push_back(std::move(dex));
	}
	return true;
	}

	// Utility class to easily iterate over the quickening data.
	class QuickeningInfoIterator {
	public:
	QuickeningInfoIterator(uint32_t dex_file_index,
	uint32_t number_of_dex_files,
	const ArrayRef<const uint8_t>& quickening_info)
	: quickening_info_(quickening_info) {
	const unaligned_uint32_t* dex_file_indices = reinterpret_cast<const unaligned_uint32_t*>(
	quickening_info.data() +
	quickening_info.size() -
	number_of_dex_files * sizeof(uint32_t));
	current_code_item_end_ = (dex_file_index == number_of_dex_files - 1)
	? dex_file_indices
	: reinterpret_cast<const unaligned_uint32_t*>(
	quickening_info_.data() + dex_file_indices[dex_file_index + 1]);
	current_code_item_ptr_ = reinterpret_cast<const uint32_t*>(
	quickening_info_.data() + dex_file_indices[dex_file_index]);
	}

	bool Done() const {
	return current_code_item_ptr_ == current_code_item_end_;
	}

	void Advance() {
	current_code_item_ptr_ += 2;
	}

	uint32_t GetCurrentCodeItemOffset() const {
	return current_code_item_ptr_[0];
	}

	const ArrayRef<const uint8_t> GetCurrentQuickeningInfo() const {
	return ArrayRef<const uint8_t>(
	// Add sizeof(uint32_t) to remove the length from the data pointer.
	quickening_info_.data() + current_code_item_ptr_[1] + sizeof(uint32_t),
	reinterpret_cast<const unaligned_uint32_t>(
	quickening_info_.data() + current_code_item_ptr_[1]));
	}

	private:
	typedef __attribute__((__aligned__(1))) uint32_t unaligned_uint32_t;
	const ArrayRef<const uint8_t>& quickening_info_;
	const unaligned_uint32_t* current_code_item_ptr_;
	const unaligned_uint32_t* current_code_item_end_;

	DISALLOW_COPY_AND_ASSIGN(QuickeningInfoIterator);
	};

	void VdexFile::Unquicken(const std::vector<const DexFile*>& dex_files,
	const ArrayRef<const uint8_t>& quickening_info) {
	if (quickening_info.size() == 0) {
	// Bail early if there is no quickening info.
	return;
	}
	// We do not decompile a RETURN_VOID_NO_BARRIER into a RETURN_VOID, as the quickening
	// optimization does not depend on the boot image (the optimization relies on not
	// having final fields in a class, which does not change for an app).
	constexpr bool kDecompileReturnInstruction = false;
	for (uint32_t i = 0; i < dex_files.size(); ++i) {
	for (QuickeningInfoIterator it(i, dex_files.size(), quickening_info);
	!it.Done();
	it.Advance()) {
	optimizer::ArtDecompileDEX(
	*dex_files[i]->GetCodeItem(it.GetCurrentCodeItemOffset()),
	it.GetCurrentQuickeningInfo(),
	kDecompileReturnInstruction);
	}
	}
	}

	static constexpr uint32_t kNoDexFile = -1;

	uint32_t VdexFile::GetDexFileIndex(const DexFile& dex_file) const {
	uint32_t dex_index = 0;
	for (const uint8_t* dex_file_start = GetNextDexFileData(nullptr);
	dex_file_start != dex_file.Begin();
	dex_file_start = GetNextDexFileData(dex_file_start)) {
	if (dex_file_start == nullptr) {
	return kNoDexFile;
	}
	dex_index++;
	}
	return dex_index;
	}

	void VdexFile::FullyUnquickenDexFile(const DexFile& target_dex_file,
	const DexFile& original_dex_file) const {
	uint32_t dex_index = GetDexFileIndex(original_dex_file);
	if (dex_index == kNoDexFile) {
	return;
	}

	constexpr bool kDecompileReturnInstruction = true;
	QuickeningInfoIterator it(dex_index, GetHeader().GetNumberOfDexFiles(), GetQuickeningInfo());
	// Iterate over the class definitions. Even if there is no quickening info,
	// we want to unquicken RETURN_VOID_NO_BARRIER instruction.
	for (uint32_t i = 0; i < target_dex_file.NumClassDefs(); ++i) {
	const DexFile::ClassDef& class_def = target_dex_file.GetClassDef(i);
	const uint8_t* class_data = target_dex_file.GetClassData(class_def);
	if (class_data != nullptr) {
	for (ClassDataItemIterator class_it(target_dex_file, class_data);
	class_it.HasNext();
	class_it.Next()) {
	if (class_it.IsAtMethod() && class_it.GetMethodCodeItem() != nullptr) {
	uint32_t offset = class_it.GetMethodCodeItemOffset();
	if (!it.Done() && offset == it.GetCurrentCodeItemOffset()) {
	optimizer::ArtDecompileDEX(
	*class_it.GetMethodCodeItem(),
	it.GetCurrentQuickeningInfo(),
	kDecompileReturnInstruction);
	it.Advance();
	} else {
	optimizer::ArtDecompileDEX(*class_it.GetMethodCodeItem(),
	ArrayRef<const uint8_t>(nullptr, 0),
	kDecompileReturnInstruction);
	}
	}
	}
	}
	}
	}

	const uint8_t* VdexFile::GetQuickenedInfoOf(const DexFile& dex_file,
	uint32_t code_item_offset) const {
	if (GetQuickeningInfo().size() == 0) {
	// Bail early if there is no quickening info.
	return nullptr;
	}

	uint32_t dex_index = GetDexFileIndex(dex_file);
	if (dex_index == kNoDexFile) {
	return nullptr;
	}

	for (QuickeningInfoIterator it(dex_index, GetHeader().GetNumberOfDexFiles(), GetQuickeningInfo());
	!it.Done();
	it.Advance()) {
	if (code_item_offset == it.GetCurrentCodeItemOffset()) {
	return it.GetCurrentQuickeningInfo().data();
	}
	}
	return nullptr;
	}

	} // namespace art