//
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// Copyright (C) 2015 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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#ifndef UPDATE_ENGINE_PAYLOAD_GENERATOR_FILESYSTEM_INTERFACE_H_
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#define UPDATE_ENGINE_PAYLOAD_GENERATOR_FILESYSTEM_INTERFACE_H_
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// This class is used to abstract a filesystem and iterate the blocks
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// associated with the files and filesystem structures.
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// For the purposes of the update payload generation, a filesystem is a
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// formatted partition composed by fixed-size blocks, since that's the interface
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// used in the update payload.
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <memory>
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#include <string>
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#include <vector>
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#include <base/macros.h>
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#include <brillo/key_value_store.h>
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#include <puffin/utils.h>
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#include "update_engine/update_metadata.pb.h"
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namespace chromeos_update_engine {
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class FilesystemInterface {
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public:
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// This represents a file or pseudo-file in the filesystem. It can include
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// all sort of files, like symlinks, hardlinks, directories and even a file
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// entry representing the metadata, free space, journaling data, etc.
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struct File {
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File() { memset(&file_stat, 0, sizeof(file_stat)); }
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// The stat struct for the file. This is invalid (inode 0) for some
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// pseudo-files.
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struct stat file_stat;
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// The absolute path to the file inside the filesystem, for example,
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// "/usr/bin/bash". For pseudo-files, like blocks associated to internal
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// filesystem tables or free space, the path doesn't start with a /.
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std::string name;
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// The list of all physical blocks holding the data of this file in
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// the same order as the logical data. All the block numbers shall be
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// between 0 and GetBlockCount() - 1. The blocks are encoded in extents,
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// indicating the starting block, and the number of consecutive blocks.
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std::vector<Extent> extents;
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// All the deflate locations in the file. These locations are not relative
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// to the extents. They are relative to the file system itself.
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std::vector<puffin::BitExtent> deflates;
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};
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virtual ~FilesystemInterface() = default;
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// Returns the size of a block in the filesystem.
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virtual size_t GetBlockSize() const = 0;
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// Returns the number of blocks in the filesystem.
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virtual size_t GetBlockCount() const = 0;
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// Stores in |files| the list of files and pseudo-files in the filesystem. See
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// FileInterface for details. The paths returned by this method shall not
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// be repeated; but the same block could be present in more than one file as
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// happens for example with hard-linked files, but not limited to those cases.
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// Returns whether the function succeeded.
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virtual bool GetFiles(std::vector<File>* files) const = 0;
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// Load the image settings stored in the filesystem in the
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// /etc/update_engine.conf file. Returns whether the settings were found.
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virtual bool LoadSettings(brillo::KeyValueStore* store) const = 0;
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protected:
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FilesystemInterface() = default;
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private:
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DISALLOW_COPY_AND_ASSIGN(FilesystemInterface);
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};
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} // namespace chromeos_update_engine
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#endif // UPDATE_ENGINE_PAYLOAD_GENERATOR_FILESYSTEM_INTERFACE_H_
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