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//
// Copyright (C) 2018 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 "update_engine/payload_generator/boot_img_filesystem.h"
#include <base/logging.h>
#include <bootimg.h>
#include <brillo/secure_blob.h>
#include <puffin/utils.h>
#include "update_engine/common/utils.h"
#include "update_engine/payload_generator/delta_diff_generator.h"
#include "update_engine/payload_generator/extent_ranges.h"
using std::string;
using std::unique_ptr;
using std::vector;
namespace chromeos_update_engine {
unique_ptr<BootImgFilesystem> BootImgFilesystem::CreateFromFile(
const string& filename) {
if (filename.empty())
return nullptr;
if (brillo::Blob header_magic;
!utils::ReadFileChunk(filename, 0, BOOT_MAGIC_SIZE, &header_magic) ||
memcmp(header_magic.data(), BOOT_MAGIC, BOOT_MAGIC_SIZE) != 0) {
return nullptr;
}
// The order of image header fields are different in version 3 from the
// previous versions. But the position of "header_version" is fixed at #9
// across all image headers.
// See details in system/tools/mkbootimg/include/bootimg/bootimg.h
constexpr size_t header_version_offset =
BOOT_MAGIC_SIZE + 8 * sizeof(uint32_t);
brillo::Blob header_version_blob;
if (!utils::ReadFileChunk(filename,
header_version_offset,
sizeof(uint32_t),
&header_version_blob)) {
return nullptr;
}
uint32_t header_version =
*reinterpret_cast<uint32_t*>(header_version_blob.data());
if (header_version > 3) {
LOG(WARNING) << "Boot image header version " << header_version
<< " isn't supported for parsing";
return nullptr;
}
// Read the bytes of boot image header based on the header version.
size_t header_size =
header_version == 3 ? sizeof(boot_img_hdr_v3) : sizeof(boot_img_hdr_v0);
brillo::Blob header_blob;
if (!utils::ReadFileChunk(filename, 0, header_size, &header_blob)) {
return nullptr;
}
unique_ptr<BootImgFilesystem> result(new BootImgFilesystem());
result->filename_ = filename;
if (header_version < 3) {
auto hdr_v0 = reinterpret_cast<boot_img_hdr_v0*>(header_blob.data());
CHECK_EQ(0, memcmp(hdr_v0->magic, BOOT_MAGIC, BOOT_MAGIC_SIZE));
CHECK_LT(hdr_v0->header_version, 3u);
result->kernel_size_ = hdr_v0->kernel_size;
result->ramdisk_size_ = hdr_v0->ramdisk_size;
result->page_size_ = hdr_v0->page_size;
} else {
auto hdr_v3 = reinterpret_cast<boot_img_hdr_v3*>(header_blob.data());
CHECK_EQ(0, memcmp(hdr_v3->magic, BOOT_MAGIC, BOOT_MAGIC_SIZE));
CHECK_EQ(3u, hdr_v3->header_version);
result->kernel_size_ = hdr_v3->kernel_size;
result->ramdisk_size_ = hdr_v3->ramdisk_size;
result->page_size_ = 4096;
}
CHECK_GT(result->page_size_, 0u);
return result;
}
size_t BootImgFilesystem::GetBlockSize() const {
// Page size may not be 4K, but we currently only support 4K block size.
return kBlockSize;
}
size_t BootImgFilesystem::GetBlockCount() const {
return utils::DivRoundUp(utils::FileSize(filename_), kBlockSize);
}
FilesystemInterface::File BootImgFilesystem::GetFile(const string& name,
uint64_t offset,
uint64_t size) const {
File file;
file.name = name;
file.extents = {ExtentForBytes(kBlockSize, offset, size)};
brillo::Blob data;
if (utils::ReadFileChunk(filename_, offset, size, &data)) {
constexpr size_t kGZipHeaderSize = 10;
// Check GZip header magic.
if (data.size() > kGZipHeaderSize && data[0] == 0x1F && data[1] == 0x8B) {
if (!puffin::LocateDeflatesInGzip(data, &file.deflates)) {
LOG(ERROR) << "Error occurred parsing gzip " << name << " at offset "
<< offset << " of " << filename_ << ", found "
<< file.deflates.size() << " deflates.";
return file;
}
for (auto& deflate : file.deflates) {
deflate.offset += offset * 8;
}
}
}
return file;
}
bool BootImgFilesystem::GetFiles(vector<File>* files) const {
files->clear();
const uint64_t file_size = utils::FileSize(filename_);
// The first page is header.
uint64_t offset = page_size_;
if (kernel_size_ > 0 && offset + kernel_size_ <= file_size) {
files->emplace_back(GetFile("<kernel>", offset, kernel_size_));
}
offset += utils::RoundUp(kernel_size_, page_size_);
if (ramdisk_size_ > 0 && offset + ramdisk_size_ <= file_size) {
files->emplace_back(GetFile("<ramdisk>", offset, ramdisk_size_));
}
return true;
}
bool BootImgFilesystem::LoadSettings(brillo::KeyValueStore* store) const {
return false;
}
} // namespace chromeos_update_engine
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