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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 #if defined(__clang__)
27 // TODO: Remove these pragmas when b/35721782 is fixed.
28 #pragma clang diagnostic push
29 #pragma clang diagnostic ignored "-Wmacro-redefined"
30 #endif
31 #include <ext2fs/ext2fs.h>
32 #if defined(__clang__)
33 #pragma clang diagnostic pop
34 #endif
35 
36 namespace chromeos_update_engine {
37 
38 class Ext2Filesystem : public FilesystemInterface {
39  public:
40   // Creates an Ext2Filesystem from a ext2 formatted filesystem stored in a
41   // file. The file doesn't need to be loop-back mounted.
42   static std::unique_ptr<Ext2Filesystem> CreateFromFile(
43       const std::string& filename);
44   virtual ~Ext2Filesystem();
45 
46   // FilesystemInterface overrides.
47   size_t GetBlockSize() const override;
48   size_t GetBlockCount() const override;
49 
50   // GetFiles will return one FilesystemInterface::File for every file and every
51   // directory in the filesystem. Hard-linked files will appear in the list
52   // several times with the same list of blocks.
53   // On addition to actual files, it also returns these pseudo-files:
54   //  <free-space>: With all the unallocated data-blocks.
55   //  <inode-blocks>: Will all the data-blocks for second and third level inodes
56   //    of all the files.
57   //  <group-descriptors>: With the block group descriptor and their reserved
58   //    space.
59   //  <metadata>: With the rest of ext2 metadata blocks, such as superblocks
60   //    and bitmap tables.
61   bool GetFiles(std::vector<File>* files) const override;
62 
63   bool LoadSettings(brillo::KeyValueStore* store) const override;
64 
65  private:
66   Ext2Filesystem() = default;
67 
68   // The ext2 main data structure holding the filesystem.
69   ext2_filsys filsys_ = nullptr;
70 
71   // The file where the filesystem is stored.
72   std::string filename_;
73 
74   DISALLOW_COPY_AND_ASSIGN(Ext2Filesystem);
75 };
76 
77 }  // namespace chromeos_update_engine
78 
79 #endif  // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXT2_FILESYSTEM_H_
80