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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 // TODO: Remove these pragmas when b/35721782 is fixed.
     27 #pragma clang diagnostic push
     28 #pragma clang diagnostic ignored "-Wmacro-redefined"
     29 #include <ext2fs/ext2fs.h>
     30 #pragma clang diagnostic pop
     31 
     32 namespace chromeos_update_engine {
     33 
     34 class Ext2Filesystem : public FilesystemInterface {
     35  public:
     36   // Creates an Ext2Filesystem from a ext2 formatted filesystem stored in a
     37   // file. The file doesn't need to be loop-back mounted.
     38   static std::unique_ptr<Ext2Filesystem> CreateFromFile(
     39       const std::string& filename);
     40   virtual ~Ext2Filesystem();
     41 
     42   // FilesystemInterface overrides.
     43   size_t GetBlockSize() const override;
     44   size_t GetBlockCount() const override;
     45 
     46   // GetFiles will return one FilesystemInterface::File for every file and every
     47   // directory in the filesystem. Hard-linked files will appear in the list
     48   // several times with the same list of blocks.
     49   // On addition to actual files, it also returns these pseudo-files:
     50   //  <free-space>: With all the unallocated data-blocks.
     51   //  <inode-blocks>: Will all the data-blocks for second and third level inodes
     52   //    of all the files.
     53   //  <group-descriptors>: With the block group descriptor and their reserved
     54   //    space.
     55   //  <metadata>: With the rest of ext2 metadata blocks, such as superblocks
     56   //    and bitmap tables.
     57   bool GetFiles(std::vector<File>* files) const override;
     58 
     59   bool LoadSettings(brillo::KeyValueStore* store) const override;
     60 
     61  private:
     62   Ext2Filesystem() = default;
     63 
     64   // The ext2 main data structure holding the filesystem.
     65   ext2_filsys filsys_ = nullptr;
     66 
     67   // The file where the filesystem is stored.
     68   std::string filename_;
     69 
     70   DISALLOW_COPY_AND_ASSIGN(Ext2Filesystem);
     71 };
     72 
     73 }  // namespace chromeos_update_engine
     74 
     75 #endif  // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXT2_FILESYSTEM_H_
     76