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//
// Copyright (C) 2020 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/cow_size_estimator.h"
#include <string>
#include <utility>
#include <vector>
#include <android-base/unique_fd.h>
#include <libsnapshot/cow_writer.h>
#include "update_engine/common/cow_operation_convert.h"
#include "update_engine/common/utils.h"
#include "update_engine/update_metadata.pb.h"
namespace chromeos_update_engine {
using android::snapshot::CowWriter;
namespace {
bool PerformReplaceOp(const InstallOperation& op,
CowWriter* writer,
FileDescriptorPtr target_fd,
size_t block_size) {
std::vector<unsigned char> buffer;
for (const auto& extent : op.dst_extents()) {
buffer.resize(extent.num_blocks() * block_size);
// No need to read from payload.bin then decompress, just read from target
// directly.
ssize_t bytes_read = 0;
auto success = utils::ReadAll(target_fd,
buffer.data(),
buffer.size(),
extent.start_block() * block_size,
&bytes_read);
TEST_AND_RETURN_FALSE(success);
CHECK_EQ(static_cast<size_t>(bytes_read), buffer.size());
TEST_AND_RETURN_FALSE(writer->AddRawBlocks(
extent.start_block(), buffer.data(), buffer.size()));
}
return true;
}
bool PerformZeroOp(const InstallOperation& op,
CowWriter* writer,
size_t block_size) {
for (const auto& extent : op.dst_extents()) {
TEST_AND_RETURN_FALSE(
writer->AddZeroBlocks(extent.start_block(), extent.num_blocks()));
}
return true;
}
bool WriteAllCowOps(size_t block_size,
const std::vector<CowOperation>& converted,
android::snapshot::ICowWriter* cow_writer,
FileDescriptorPtr target_fd) {
std::vector<uint8_t> buffer(block_size);
for (const auto& cow_op : converted) {
switch (cow_op.op) {
case CowOperation::CowCopy:
if (cow_op.src_block == cow_op.dst_block) {
continue;
}
TEST_AND_RETURN_FALSE(
cow_writer->AddCopy(cow_op.dst_block, cow_op.src_block));
break;
case CowOperation::CowReplace:
ssize_t bytes_read = 0;
TEST_AND_RETURN_FALSE(chromeos_update_engine::utils::ReadAll(
target_fd,
buffer.data(),
block_size,
cow_op.dst_block * block_size,
&bytes_read));
if (bytes_read <= 0 || static_cast<size_t>(bytes_read) != block_size) {
LOG(ERROR) << "source_fd->Read failed: " << bytes_read;
return false;
}
TEST_AND_RETURN_FALSE(cow_writer->AddRawBlocks(
cow_op.dst_block, buffer.data(), block_size));
break;
}
}
return true;
}
} // namespace
size_t EstimateCowSize(
FileDescriptorPtr target_fd,
const google::protobuf::RepeatedPtrField<InstallOperation>& operations,
const google::protobuf::RepeatedPtrField<CowMergeOperation>&
merge_operations,
size_t block_size,
std::string compression) {
android::snapshot::CowWriter cow_writer{
{.block_size = static_cast<uint32_t>(block_size),
.compression = std::move(compression)}};
// CowWriter treats -1 as special value, will discard all the data but still
// reports Cow size. Good for estimation purposes
cow_writer.Initialize(android::base::borrowed_fd{-1});
CHECK(CowDryRun(
target_fd, operations, merge_operations, block_size, &cow_writer));
CHECK(cow_writer.Finalize());
return cow_writer.GetCowSize();
}
bool CowDryRun(
FileDescriptorPtr target_fd,
const google::protobuf::RepeatedPtrField<InstallOperation>& operations,
const google::protobuf::RepeatedPtrField<CowMergeOperation>&
merge_operations,
size_t block_size,
android::snapshot::CowWriter* cow_writer) {
const auto converted = ConvertToCowOperations(operations, merge_operations);
WriteAllCowOps(block_size, converted, cow_writer, target_fd);
cow_writer->AddLabel(0);
for (const auto& op : operations) {
switch (op.type()) {
case InstallOperation::REPLACE:
case InstallOperation::REPLACE_BZ:
case InstallOperation::REPLACE_XZ:
TEST_AND_RETURN_FALSE(
PerformReplaceOp(op, cow_writer, target_fd, block_size));
break;
case InstallOperation::ZERO:
case InstallOperation::DISCARD:
TEST_AND_RETURN_FALSE(PerformZeroOp(op, cow_writer, block_size));
break;
case InstallOperation::SOURCE_COPY:
case InstallOperation::MOVE:
// Already handeled by WriteAllCowOps,
break;
case InstallOperation::SOURCE_BSDIFF:
case InstallOperation::BROTLI_BSDIFF:
case InstallOperation::PUFFDIFF:
case InstallOperation::BSDIFF:
// We might do something special by adding CowBsdiff to CowWriter.
// For now proceed the same way as normal REPLACE operation.
TEST_AND_RETURN_FALSE(
PerformReplaceOp(op, cow_writer, target_fd, block_size));
break;
}
// Arbitrary label number, we won't be resuming use these labels here.
// They are emitted just to keep size estimates accurate. As update_engine
// emits 1 label for every op.
cow_writer->AddLabel(2);
}
// TODO(zhangkelvin) Take FEC extents into account once VABC stabilizes
return true;
}
} // namespace chromeos_update_engine
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