src/dev/storage/disk_image.hh

   1 /*
   2  * Copyright (c) 2001-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Nathan Binkert
  29  */
  30
  31 /** @file
  32  * Disk Image Interfaces
  33  */
  34
  35 #ifndef __DEV_STORAGE_DISK_IMAGE_HH__
  36 #define __DEV_STORAGE_DISK_IMAGE_HH__
  37
  38 #include <fstream>
  39 #include <unordered_map>
  40
  41 #include "params/CowDiskImage.hh"
  42 #include "params/DiskImage.hh"
  43 #include "params/RawDiskImage.hh"
  44 #include "sim/sim_object.hh"
  45
  46 #define SectorSize (512)
  47
  48 /**
  49  * Basic interface for accessing a disk image.
  50  */
  51 class DiskImage : public SimObject
  52 {
  53   protected:
  54     bool initialized;
  55
  56   public:
  57     typedef DiskImageParams Params;
  58     DiskImage(const Params *p) : SimObject(p), initialized(false) {}
  59     virtual ~DiskImage() {}
  60
  61     virtual std::streampos size() const = 0;
  62
  63     virtual std::streampos read(uint8_t *data,
  64                                 std::streampos offset) const = 0;
  65     virtual std::streampos write(const uint8_t *data,
  66                                  std::streampos offset) = 0;
  67 };
  68
  69 /**
  70  * Specialization for accessing a raw disk image
  71  */
  72 class RawDiskImage : public DiskImage
  73 {
  74   protected:
  75     mutable std::fstream stream;
  76     std::string file;
  77     bool readonly;
  78     mutable std::streampos disk_size;
  79
  80   public:
  81     typedef RawDiskImageParams Params;
  82     RawDiskImage(const Params *p);
  83     ~RawDiskImage();
  84
  85     void notifyFork() override;
  86
  87     void close();
  88     void open(const std::string &filename, bool rd_only = false);
  89
  90     std::streampos size() const override;
  91
  92     std::streampos read(uint8_t *data, std::streampos offset) const override;
  93     std::streampos write(const uint8_t *data, std::streampos offset) override;
  94 };
  95
  96 /**
  97  * Specialization for accessing a copy-on-write disk image layer.
  98  * A copy-on-write(COW) layer must be stacked on top of another disk
  99  * image layer this layer can be another CowDiskImage, or a
 100  * RawDiskImage.
 101  *
 102  * This object is designed to provide a mechanism for persistant
 103  * changes to a main disk image, or to provide a place for temporary
 104  * changes to the image to take place that later may be thrown away.
 105  */
 106 class CowDiskImage : public DiskImage
 107 {
 108   public:
 109     static const uint32_t VersionMajor;
 110     static const uint32_t VersionMinor;
 111
 112   protected:
 113     struct Sector {
 114         uint8_t data[SectorSize];
 115     };
 116     typedef std::unordered_map<uint64_t, Sector *> SectorTable;
 117
 118   protected:
 119     std::string filename;
 120     DiskImage *child;
 121     SectorTable *table;
 122
 123   public:
 124     typedef CowDiskImageParams Params;
 125     CowDiskImage(const Params *p);
 126     ~CowDiskImage();
 127
 128     void notifyFork() override;
 129
 130     void initSectorTable(int hash_size);
 131     bool open(const std::string &file);
 132     void save() const;
 133     void save(const std::string &file) const;
 134     void writeback();
 135
 136     void serialize(CheckpointOut &cp) const override;
 137     void unserialize(CheckpointIn &cp) override;
 138
 139     std::streampos size() const override;
 140
 141     std::streampos read(uint8_t *data, std::streampos offset) const override;
 142     std::streampos write(const uint8_t *data, std::streampos offset) override;
 143 };
 144
 145 void SafeRead(std::ifstream &stream, void *data, int count);
 146
 147 template<class T>
 148 void SafeRead(std::ifstream &stream, T &data);
 149
 150 template<class T>
 151 void SafeReadSwap(std::ifstream &stream, T &data);
 152
 153 void SafeWrite(std::ofstream &stream, const void *data, int count);
 154
 155 template<class T>
 156 void SafeWrite(std::ofstream &stream, const T &data);
 157
 158 template<class T>
 159 void SafeWriteSwap(std::ofstream &stream, const T &data);
 160
 161 #endif // __DEV_STORAGE_DISK_IMAGE_HH__