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      1 //
      2 // Copyright (C) 2015 The Android Open Source Project
      3 //
      4 // Licensed under the Apache License, Version 2.0 (the "License");
      5 // you may not use this file except in compliance with the License.
      6 // You may obtain a copy of the License at
      7 //
      8 //      http://www.apache.org/licenses/LICENSE-2.0
      9 //
     10 // Unless required by applicable law or agreed to in writing, software
     11 // distributed under the License is distributed on an "AS IS" BASIS,
     12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 // See the License for the specific language governing permissions and
     14 // limitations under the License.
     15 //
     16 
     17 #ifndef UPDATE_ENGINE_PAYLOAD_GENERATOR_EXT2_FILESYSTEM_H_
     18 #define UPDATE_ENGINE_PAYLOAD_GENERATOR_EXT2_FILESYSTEM_H_
     19 
     20 #include "update_engine/payload_generator/filesystem_interface.h"
     21 
     22 #include <memory>
     23 #include <string>
     24 #include <vector>
     25 
     26 #include <ext2fs/ext2fs.h>
     27 
     28 namespace chromeos_update_engine {
     29 
     30 class Ext2Filesystem : public FilesystemInterface {
     31  public:
     32   // Creates an Ext2Filesystem from a ext2 formatted filesystem stored in a
     33   // file. The file doesn't need to be loop-back mounted.
     34   static std::unique_ptr<Ext2Filesystem> CreateFromFile(
     35       const std::string& filename);
     36   virtual ~Ext2Filesystem();
     37 
     38   // FilesystemInterface overrides.
     39   size_t GetBlockSize() const override;
     40   size_t GetBlockCount() const override;
     41 
     42   // GetFiles will return one FilesystemInterface::File for every file and every
     43   // directory in the filesystem. Hard-linked files will appear in the list
     44   // several times with the same list of blocks.
     45   // On addition to actual files, it also returns these pseudo-files:
     46   //  <free-space>: With all the unallocated data-blocks.
     47   //  <inode-blocks>: Will all the data-blocks for second and third level inodes
     48   //    of all the files.
     49   //  <group-descriptors>: With the block group descriptor and their reserved
     50   //    space.
     51   //  <metadata>: With the rest of ext2 metadata blocks, such as superblocks
     52   //    and bitmap tables.
     53   bool GetFiles(std::vector<File>* files) const override;
     54 
     55   bool LoadSettings(brillo::KeyValueStore* store) const override;
     56 
     57  private:
     58   Ext2Filesystem() = default;
     59 
     60   // The ext2 main data structure holding the filesystem.
     61   ext2_filsys filsys_ = nullptr;
     62 
     63   // The file where the filesystem is stored.
     64   std::string filename_;
     65 
     66   DISALLOW_COPY_AND_ASSIGN(Ext2Filesystem);
     67 };
     68 
     69 }  // namespace chromeos_update_engine
     70 
     71 #endif  // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXT2_FILESYSTEM_H_
     72