1 //
2 // Copyright (C) 2014 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_CONSUMER_MTD_FILE_DESCRIPTOR_H_
18 #define UPDATE_ENGINE_PAYLOAD_CONSUMER_MTD_FILE_DESCRIPTOR_H_
19 
20 // This module defines file descriptors that deal with NAND media. We are
21 // concerned with raw NAND access (as MTD device), and through UBI layer.
22 
23 #include <mtdutils.h>
24 
25 #include "update_engine/payload_consumer/file_descriptor.h"
26 
27 namespace chromeos_update_engine {
28 
29 // A class defining the file descriptor API for raw MTD device. This file
30 // descriptor supports either random read, or sequential write but not both at
31 // once.
32 class MtdFileDescriptor : public EintrSafeFileDescriptor {
33  public:
34   MtdFileDescriptor();
35 
36   static bool IsMtd(const char* path);
37 
38   bool Open(const char* path, int flags, mode_t mode) override;
39   bool Open(const char* path, int flags) override;
40   ssize_t Read(void* buf, size_t count) override;
41   ssize_t Write(const void* buf, size_t count) override;
42   off64_t Seek(off64_t offset, int whence) override;
BlkIoctl(int request,uint64_t start,uint64_t length,int * result)43   bool BlkIoctl(int request,
44                 uint64_t start,
45                 uint64_t length,
46                 int* result) override {
47     return false;
48   }
49   bool Close() override;
50 
51  private:
52   std::unique_ptr<MtdReadContext, decltype(&mtd_read_close)> read_ctx_;
53   std::unique_ptr<MtdWriteContext, decltype(&mtd_write_close)> write_ctx_;
54   uint64_t nr_written_;
55 };
56 
57 struct UbiVolumeInfo {
58   // Number of eraseblocks.
59   uint64_t reserved_ebs;
60   // Size of each eraseblock.
61   uint64_t eraseblock_size;
62 };
63 
64 // A file descriptor to update a UBI volume, similar to MtdFileDescriptor.
65 // Once the file descriptor is opened for write, the volume is marked as being
66 // updated. The volume will not be usable until an update is completed. See
67 // UBI_IOCVOLUP ioctl operation.
68 class UbiFileDescriptor : public EintrSafeFileDescriptor {
69  public:
70   // Perform some queries about |path| to see if it is a UBI volume.
71   static bool IsUbi(const char* path);
72 
73   bool Open(const char* path, int flags, mode_t mode) override;
74   bool Open(const char* path, int flags) override;
75   ssize_t Read(void* buf, size_t count) override;
76   ssize_t Write(const void* buf, size_t count) override;
77   off64_t Seek(off64_t offset, int whence) override;
BlkIoctl(int request,uint64_t start,uint64_t length,int * result)78   bool BlkIoctl(int request,
79                 uint64_t start,
80                 uint64_t length,
81                 int* result) override {
82     return false;
83   }
84   bool Close() override;
85 
86  private:
87   enum Mode {
88     kReadOnly,
89     kWriteOnly
90   };
91 
92   uint64_t usable_eb_blocks_;
93   uint64_t eraseblock_size_;
94   uint64_t volume_size_;
95   uint64_t nr_written_;
96 
97   Mode mode_;
98 };
99 
100 }  // namespace chromeos_update_engine
101 
102 #endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_MTD_FILE_DESCRIPTOR_H_
103