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
  29 /** @file
  30  * Disk Image Interfaces
  31  */
  32
  33 #ifndef __DEV_STORAGE_DISK_IMAGE_HH__
  34 #define __DEV_STORAGE_DISK_IMAGE_HH__
  35
  36 #include <fstream>
  37 #include <unordered_map>
  38
  39 #include "params/CowDiskImage.hh"
  40 #include "params/DiskImage.hh"
  41 #include "params/RawDiskImage.hh"
  42 #include "sim/sim_object.hh"
  43
  44 #define SectorSize (512)
  45
  46 /**
  47  * Basic interface for accessing a disk image.
  48  */
  49 class DiskImage : public SimObject
  50 {
  51   protected:
  52     bool initialized;
  53
  54   public:
  55     typedef DiskImageParams Params;
  56     DiskImage(const Params *p) : SimObject(p), initialized(false) {}
  57     virtual ~DiskImage() {}
  58
  59     virtual std::streampos size() const = 0;
  60
  61     virtual std::streampos read(uint8_t *data,
  62                                 std::streampos offset) const = 0;
  63     virtual std::streampos write(const uint8_t *data,
  64                                  std::streampos offset) = 0;
  65 };
  66
  67 /**
  68  * Specialization for accessing a raw disk image
  69  */
  70 class RawDiskImage : public DiskImage
  71 {
  72   protected:
  73     mutable std::fstream stream;
  74     std::string file;
  75     bool readonly;
  76     mutable std::streampos disk_size;
  77
  78   public:
  79     typedef RawDiskImageParams Params;
  80     RawDiskImage(const Params *p);
  81     ~RawDiskImage();
  82
  83     void notifyFork() override;
  84
  85     void close();
  86     void open(const std::string &filename, bool rd_only = false);
  87
  88     std::streampos size() const override;
  89
  90     std::streampos read(uint8_t *data, std::streampos offset) const override;
  91     std::streampos write(const uint8_t *data, std::streampos offset) override;
  92 };
  93
  94 /**
  95  * Specialization for accessing a copy-on-write disk image layer.
  96  * A copy-on-write(COW) layer must be stacked on top of another disk
  97  * image layer this layer can be another CowDiskImage, or a
  98  * RawDiskImage.
  99  *
 100  * This object is designed to provide a mechanism for persistant
 101  * changes to a main disk image, or to provide a place for temporary
 102  * changes to the image to take place that later may be thrown away.
 103  */
 104 class CowDiskImage : public DiskImage
 105 {
 106   public:
 107     static const uint32_t VersionMajor;
 108     static const uint32_t VersionMinor;
 109
 110   protected:
 111     struct Sector {
 112         uint8_t data[SectorSize];
 113     };
 114     typedef std::unordered_map<uint64_t, Sector *> SectorTable;
 115
 116   protected:
 117     std::string filename;
 118     DiskImage *child;
 119     SectorTable *table;
 120
 121   public:
 122     typedef CowDiskImageParams Params;
 123     CowDiskImage(const Params *p);
 124     ~CowDiskImage();
 125
 126     void notifyFork() override;
 127
 128     void initSectorTable(int hash_size);
 129     bool open(const std::string &file);
 130     void save() const;
 131     void save(const std::string &file) const;
 132     void writeback();
 133
 134     void serialize(CheckpointOut &cp) const override;
 135     void unserialize(CheckpointIn &cp) override;
 136
 137     std::streampos size() const override;
 138
 139     std::streampos read(uint8_t *data, std::streampos offset) const override;
 140     std::streampos write(const uint8_t *data, std::streampos offset) override;
 141 };
 142
 143 void SafeRead(std::ifstream &stream, void *data, int count);
 144
 145 template<class T>
 146 void SafeRead(std::ifstream &stream, T &data);
 147
 148 template<class T>
 149 void SafeReadSwap(std::ifstream &stream, T &data);
 150
 151 void SafeWrite(std::ofstream &stream, const void *data, int count);
 152
 153 template<class T>
 154 void SafeWrite(std::ofstream &stream, const T &data);
 155
 156 template<class T>
 157 void SafeWriteSwap(std::ofstream &stream, const T &data);
 158
 159 #endif // __DEV_STORAGE_DISK_IMAGE_HH__