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/*
* 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.
*/
#ifndef ART_RUNTIME_VDEX_FILE_H_
#define ART_RUNTIME_VDEX_FILE_H_
#include <stdint.h>
#include <string>
#include "base/array_ref.h"
#include "base/macros.h"
#include "mem_map.h"
#include "os.h"
namespace art {
class DexFile;
// VDEX files contain extracted DEX files. The VdexFile class maps the file to
// memory and provides tools for accessing its individual sections.
//
// File format:
// VdexFile::Header fixed-length header
//
// DEX[0] array of the input DEX files
// DEX[1] the bytecode may have been quickened
// ...
// DEX[D]
//
class VdexFile {
public:
struct Header {
public:
Header(uint32_t number_of_dex_files_,
uint32_t dex_size,
uint32_t verifier_deps_size,
uint32_t quickening_info_size);
const char* GetMagic() const { return reinterpret_cast<const char*>(magic_); }
const char* GetVersion() const { return reinterpret_cast<const char*>(version_); }
bool IsMagicValid() const;
bool IsVersionValid() const;
bool IsValid() const { return IsMagicValid() && IsVersionValid(); }
uint32_t GetDexSize() const { return dex_size_; }
uint32_t GetVerifierDepsSize() const { return verifier_deps_size_; }
uint32_t GetQuickeningInfoSize() const { return quickening_info_size_; }
uint32_t GetNumberOfDexFiles() const { return number_of_dex_files_; }
static constexpr uint8_t kVdexInvalidMagic[] = { 'w', 'd', 'e', 'x' };
private:
static constexpr uint8_t kVdexMagic[] = { 'v', 'd', 'e', 'x' };
static constexpr uint8_t kVdexVersion[] = { '0', '0', '5', '\0' }; // access flags
uint8_t magic_[4];
uint8_t version_[4];
uint32_t number_of_dex_files_;
uint32_t dex_size_;
uint32_t verifier_deps_size_;
uint32_t quickening_info_size_;
friend class VdexFile;
};
typedef uint32_t VdexChecksum;
// Returns nullptr if the vdex file cannot be opened or is not valid.
static std::unique_ptr<VdexFile> Open(const std::string& vdex_filename,
bool writable,
bool low_4gb,
bool unquicken,
std::string* error_msg);
// Returns nullptr if the vdex file cannot be opened or is not valid.
static std::unique_ptr<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);
const uint8_t* Begin() const { return mmap_->Begin(); }
const uint8_t* End() const { return mmap_->End(); }
size_t Size() const { return mmap_->Size(); }
const Header& GetHeader() const {
return *reinterpret_cast<const Header*>(Begin());
}
ArrayRef<const uint8_t> GetVerifierDepsData() const {
return ArrayRef<const uint8_t>(
DexBegin() + GetHeader().GetDexSize(), GetHeader().GetVerifierDepsSize());
}
ArrayRef<const uint8_t> GetQuickeningInfo() const {
return ArrayRef<const uint8_t>(
GetVerifierDepsData().data() + GetHeader().GetVerifierDepsSize(),
GetHeader().GetQuickeningInfoSize());
}
bool IsValid() const {
return mmap_->Size() >= sizeof(Header) && GetHeader().IsValid();
}
// This method is for iterating over the dex files in the vdex. If `cursor` is null,
// the first dex file is returned. If `cursor` is not null, it must point to a dex
// file and this method returns the next dex file if there is one, or null if there
// is none.
const uint8_t* GetNextDexFileData(const uint8_t* cursor) const;
// Get the location checksum of the dex file number `dex_file_index`.
uint32_t GetLocationChecksum(uint32_t dex_file_index) const {
DCHECK_LT(dex_file_index, GetHeader().GetNumberOfDexFiles());
return reinterpret_cast<const uint32_t*>(Begin() + sizeof(Header))[dex_file_index];
}
// Opens all the dex files contained in this vdex file.
bool OpenAllDexFiles(std::vector<std::unique_ptr<const DexFile>>* dex_files,
std::string* error_msg);
// In-place unquicken the given `dex_files` based on `quickening_info`.
static void Unquicken(const std::vector<const DexFile*>& dex_files,
const ArrayRef<const uint8_t>& quickening_info);
private:
explicit VdexFile(MemMap* mmap) : mmap_(mmap) {}
bool HasDexSection() const {
return GetHeader().GetDexSize() != 0;
}
const uint8_t* DexBegin() const {
return Begin() + sizeof(Header) + GetSizeOfChecksumsSection();
}
const uint8_t* DexEnd() const {
return DexBegin() + GetHeader().GetDexSize();
}
size_t GetSizeOfChecksumsSection() const {
return sizeof(VdexChecksum) * GetHeader().GetNumberOfDexFiles();
}
std::unique_ptr<MemMap> mmap_;
DISALLOW_COPY_AND_ASSIGN(VdexFile);
};
} // namespace art
#endif // ART_RUNTIME_VDEX_FILE_H_