72 lines
2.2 KiB
C++
72 lines
2.2 KiB
C++
//
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// Copyright (C) 2021 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 <cstdint>
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#include <memory>
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#include <libsnapshot/snapshot_writer.h>
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#include "update_engine/payload_consumer/file_descriptor.h"
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namespace chromeos_update_engine {
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// A Readable/Writable FileDescriptor class. This is a simple wrapper around
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// CowWriter. Only intended to be used by FileSystemVerifierAction for writing
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// FEC. Writes must be block aligned(4096) or write will fail.
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class CowWriterFileDescriptor final : public FileDescriptor {
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public:
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explicit CowWriterFileDescriptor(
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std::unique_ptr<android::snapshot::ISnapshotWriter> cow_writer);
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// |cow_reader| should be obtained by calling |cow_writer->OpenReader()|
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CowWriterFileDescriptor(
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std::unique_ptr<android::snapshot::ISnapshotWriter> cow_writer,
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std::unique_ptr<FileDescriptor> cow_reader);
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~CowWriterFileDescriptor();
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bool Open(const char* path, int flags, mode_t mode) override;
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bool Open(const char* path, int flags) override;
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ssize_t Read(void* buf, size_t count) override;
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// |count| must be block aligned, current offset of this fd must also be block
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// aligned.
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ssize_t Write(const void* buf, size_t count) override;
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off64_t Seek(off64_t offset, int whence) override;
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uint64_t BlockDevSize() override;
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bool BlkIoctl(int request,
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uint64_t start,
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uint64_t length,
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int* result) override;
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bool Flush() override;
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bool Close() override;
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bool IsSettingErrno() override;
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bool IsOpen() override;
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private:
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std::unique_ptr<android::snapshot::ISnapshotWriter> cow_writer_;
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FileDescriptorPtr cow_reader_;
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bool dirty_ = false;
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};
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} // namespace chromeos_update_engine
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