dev/disk_image.hh

   1 /*
   2  * Copyright (c) 2001-2003 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 __DISK_IMAGE_HH__
  34 #define __DISK_IMAGE_HH__
  35
  36 #include <fstream>
  37
  38 #include "base/hashmap.hh"
  39 #include "sim/sim_object.hh"
  40
  41 #define SectorSize (512)
  42
  43 /*
  44  * Basic interface for accessing a disk image.
  45  */
  46 class DiskImage : public SimObject
  47 {
  48   protected:
  49     bool initialized;
  50
  51   public:
  52     DiskImage(const std::string &name) : SimObject(name), initialized(false) {}
  53     virtual ~DiskImage() {}
  54
  55     virtual off_t size() const = 0;
  56
  57     virtual off_t read(uint8_t *data, off_t offset) const = 0;
  58     virtual off_t write(const uint8_t *data, off_t offset) = 0;
  59 };
  60
  61 /*
  62  * Specialization for accessing a raw disk image
  63  */
  64 class RawDiskImage : public DiskImage
  65 {
  66   protected:
  67     mutable std::fstream stream;
  68     std::string file;
  69     bool readonly;
  70     mutable off_t disk_size;
  71
  72   public:
  73     RawDiskImage(const std::string &name, const std::string &filename,
  74                  bool rd_only);
  75     ~RawDiskImage();
  76
  77     void close();
  78     void open(const std::string &filename, bool rd_only = false);
  79
  80     virtual off_t size() const;
  81
  82     virtual off_t read(uint8_t *data, off_t offset) const;
  83     virtual off_t write(const uint8_t *data, off_t offset);
  84 };
  85
  86 /*
  87  * Specialization for accessing a copy-on-write disk image layer.
  88  * A copy-on-write(COW) layer must be stacked on top of another disk
  89  * image layer this layer can be another CowDiskImage, or a
  90  * RawDiskImage.
  91  *
  92  * This object is designed to provide a mechanism for persistant
  93  * changes to a main disk image, or to provide a place for temporary
  94  * changes to the image to take place that later may be thrown away.
  95  */
  96 class CowDiskImage : public DiskImage
  97 {
  98   public:
  99     static const int VersionMajor;
 100     static const int VersionMinor;
 101
 102   protected:
 103     struct Sector {
 104         uint8_t data[SectorSize];
 105     };
 106     typedef m5::hash_map<uint64_t, Sector *> SectorTable;
 107
 108   protected:
 109     std::string filename;
 110     DiskImage *child;
 111     SectorTable *table;
 112
 113   public:
 114     CowDiskImage(const std::string &name, DiskImage *kid, int hash_size);
 115     CowDiskImage(const std::string &name, DiskImage *kid, int hash_size,
 116                  const std::string &filename, bool read_only);
 117     ~CowDiskImage();
 118
 119     void init(int hash_size);
 120     bool open(const std::string &file);
 121     void save();
 122     void save(const std::string &file);
 123     void writeback();
 124     void serialize(std::ostream &os);
 125     void unserialize(Checkpoint *cp, const std::string &section);
 126
 127     virtual off_t size() const;
 128
 129     virtual off_t read(uint8_t *data, off_t offset) const;
 130     virtual off_t write(const uint8_t *data, off_t offset);
 131 };
 132
 133 #endif // __DISK_IMAGE_HH__