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124 lines
4.1 KiB
124 lines
4.1 KiB
//
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// Copyright (C) 2020 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "update_engine/payload_consumer/snapshot_extent_writer.h"
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#include <algorithm>
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#include <cstdint>
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#include <libsnapshot/cow_writer.h>
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#include "update_engine/update_metadata.pb.h"
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namespace chromeos_update_engine {
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SnapshotExtentWriter::SnapshotExtentWriter(
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android::snapshot::ICowWriter* cow_writer)
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: cow_writer_(cow_writer) {
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CHECK_NE(cow_writer, nullptr);
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}
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SnapshotExtentWriter::~SnapshotExtentWriter() {
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CHECK(buffer_.empty()) << buffer_.size();
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}
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bool SnapshotExtentWriter::Init(
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const google::protobuf::RepeatedPtrField<Extent>& extents,
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uint32_t block_size) {
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extents_ = extents;
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cur_extent_idx_ = 0;
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buffer_.clear();
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buffer_.reserve(block_size);
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block_size_ = block_size;
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return true;
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}
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size_t SnapshotExtentWriter::ConsumeWithBuffer(const uint8_t* data,
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size_t count) {
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CHECK_LT(cur_extent_idx_, static_cast<size_t>(extents_.size()));
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const auto& cur_extent = extents_[cur_extent_idx_];
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const auto cur_extent_size = cur_extent.num_blocks() * block_size_;
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if (buffer_.empty() && count >= cur_extent_size) {
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if (!cow_writer_->AddRawBlocks(
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cur_extent.start_block(), data, cur_extent_size)) {
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LOG(ERROR) << "AddRawBlocks(" << cur_extent.start_block() << ", " << data
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<< ", " << cur_extent_size << ") failed.";
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// return value is expected to be greater than 0. Return 0 to signal error
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// condition
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return 0;
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}
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if (!next_extent()) {
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CHECK_EQ(count, cur_extent_size)
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<< "Exhausted all blocks, but still have " << count - cur_extent_size
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<< " bytes left";
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}
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return cur_extent_size;
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}
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CHECK_LT(buffer_.size(), cur_extent_size)
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<< "Data left in buffer should never be >= cur_extent_size, otherwise "
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"we should have send that data to CowWriter. Buffer size: "
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<< buffer_.size() << " current extent size: " << cur_extent_size;
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size_t bytes_to_copy =
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std::min<size_t>(count, cur_extent_size - buffer_.size());
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CHECK_GT(bytes_to_copy, 0U);
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buffer_.insert(buffer_.end(), data, data + bytes_to_copy);
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CHECK_LE(buffer_.size(), cur_extent_size);
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if (buffer_.size() == cur_extent_size) {
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if (!cow_writer_->AddRawBlocks(
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cur_extent.start_block(), buffer_.data(), buffer_.size())) {
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LOG(ERROR) << "AddRawBlocks(" << cur_extent.start_block() << ", "
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<< buffer_.data() << ", " << buffer_.size() << ") failed.";
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return 0;
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}
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buffer_.clear();
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if (!next_extent()) {
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CHECK_EQ(count, bytes_to_copy) << "Exhausted all blocks, but still have "
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<< count - bytes_to_copy << " bytes left";
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}
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}
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return bytes_to_copy;
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}
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// Returns true on success.
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// This will construct a COW_REPLACE operation and forward it to CowWriter. It
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// is important that caller does not perform SOURCE_COPY operation on this
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// class, otherwise raw data will be stored. Caller should find ways to use
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// COW_COPY whenever possible.
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bool SnapshotExtentWriter::Write(const void* bytes, size_t count) {
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if (count == 0) {
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return true;
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}
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CHECK_NE(extents_.size(), 0);
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auto data = static_cast<const uint8_t*>(bytes);
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while (count > 0) {
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auto bytes_written = ConsumeWithBuffer(data, count);
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TEST_AND_RETURN_FALSE(bytes_written > 0);
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data += bytes_written;
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count -= bytes_written;
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}
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return true;
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}
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bool SnapshotExtentWriter::next_extent() {
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cur_extent_idx_++;
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return cur_extent_idx_ < static_cast<size_t>(extents_.size());
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}
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} // namespace chromeos_update_engine
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