src/dev/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 __DISK_IMAGE_HH__
  36 #define __DISK_IMAGE_HH__
  37
  38 #include <fstream>
  39
  40 #include "base/hashmap.hh"
  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 off_t size() const = 0;
  62
  63     virtual off_t read(uint8_t *data, off_t offset) const = 0;
  64     virtual off_t write(const uint8_t *data, off_t 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 off_t disk_size;
  77
  78   public:
  79     typedef RawDiskImageParams Params;
  80     RawDiskImage(const Params *p);
  81     ~RawDiskImage();
  82
  83     void close();
  84     void open(const std::string &filename, bool rd_only = false);
  85
  86     virtual off_t size() const;
  87
  88     virtual off_t read(uint8_t *data, off_t offset) const;
  89     virtual off_t write(const uint8_t *data, off_t offset);
  90 };
  91
  92 /**
  93  * Specialization for accessing a copy-on-write disk image layer.
  94  * A copy-on-write(COW) layer must be stacked on top of another disk
  95  * image layer this layer can be another CowDiskImage, or a
  96  * RawDiskImage.
  97  *
  98  * This object is designed to provide a mechanism for persistant
  99  * changes to a main disk image, or to provide a place for temporary
 100  * changes to the image to take place that later may be thrown away.
 101  */
 102 class CowDiskImage : public DiskImage
 103 {
 104   public:
 105     static const uint32_t VersionMajor;
 106     static const uint32_t VersionMinor;
 107
 108   protected:
 109     struct Sector {
 110         uint8_t data[SectorSize];
 111     };
 112     typedef m5::hash_map<uint64_t, Sector *> SectorTable;
 113
 114   protected:
 115     std::string filename;
 116     DiskImage *child;
 117     SectorTable *table;
 118
 119   public:
 120     typedef CowDiskImageParams Params;
 121     CowDiskImage(const Params *p);
 122     ~CowDiskImage();
 123
 124     void init(int hash_size);
 125     bool open(const std::string &file);
 126     void save();
 127     void save(const std::string &file);
 128     void writeback();
 129     void serialize(std::ostream &os);
 130     void unserialize(Checkpoint *cp, const std::string &section);
 131
 132     virtual off_t size() const;
 133
 134     virtual off_t read(uint8_t *data, off_t offset) const;
 135     virtual off_t write(const uint8_t *data, off_t offset);
 136 };
 137
 138 #endif // __DISK_IMAGE_HH__