/*
* 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/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_;
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;
}
void VdexFile::Unquicken(const std::vector<const DexFile*>& dex_files,
const ArrayRef<const uint8_t>& quickening_info) {
if (quickening_info.size() == 0) {
// If there is no quickening info, we bail early, as the code below expects at
// least the size of quickening data for each method that has a code item.
return;
}
const uint8_t* quickening_info_ptr = quickening_info.data();
const uint8_t* const quickening_info_end = quickening_info.data() + quickening_info.size();
for (const DexFile* dex_file : dex_files) {
for (uint32_t i = 0; i < dex_file->NumClassDefs(); ++i) {
const DexFile::ClassDef& class_def = dex_file->GetClassDef(i);
const uint8_t* class_data = dex_file->GetClassData(class_def);
if (class_data == nullptr) {
continue;
}
ClassDataItemIterator it(*dex_file, class_data);
// Skip fields
while (it.HasNextStaticField()) {
it.Next();
}
while (it.HasNextInstanceField()) {
it.Next();
}
while (it.HasNextDirectMethod()) {
const DexFile::CodeItem* code_item = it.GetMethodCodeItem();
if (code_item != nullptr) {
uint32_t quickening_size = *reinterpret_cast<const uint32_t*>(quickening_info_ptr);
quickening_info_ptr += sizeof(uint32_t);
optimizer::ArtDecompileDEX(*code_item,
ArrayRef<const uint8_t>(quickening_info_ptr, quickening_size),
/* decompile_return_instruction */ false);
quickening_info_ptr += quickening_size;
}
it.Next();
}
while (it.HasNextVirtualMethod()) {
const DexFile::CodeItem* code_item = it.GetMethodCodeItem();
if (code_item != nullptr) {
uint32_t quickening_size = *reinterpret_cast<const uint32_t*>(quickening_info_ptr);
quickening_info_ptr += sizeof(uint32_t);
optimizer::ArtDecompileDEX(*code_item,
ArrayRef<const uint8_t>(quickening_info_ptr, quickening_size),
/* decompile_return_instruction */ false);
quickening_info_ptr += quickening_size;
}
it.Next();
}
DCHECK(!it.HasNext());
}
}
if (quickening_info_ptr != quickening_info_end) {
LOG(FATAL) << "Failed to use all quickening info";
}
}
} // namespace art