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 "sim/sim_object.hh"
  42
  43 #define SectorSize (512)
  44
  45 /**
  46  * Basic interface for accessing a disk image.
  47  */
  48 class DiskImage : public SimObject
  49 {
  50   protected:
  51     bool initialized;
  52
  53   public:
  54     DiskImage(const std::string &name) : SimObject(name), initialized(false) {}
  55     virtual ~DiskImage() {}
  56
  57     virtual off_t size() const = 0;
  58
  59     virtual off_t read(uint8_t *data, off_t offset) const = 0;
  60     virtual off_t write(const uint8_t *data, off_t offset) = 0;
  61 };
  62
  63 /**
  64  * Specialization for accessing a raw disk image
  65  */
  66 class RawDiskImage : public DiskImage
  67 {
  68   protected:
  69     mutable std::fstream stream;
  70     std::string file;
  71     bool readonly;
  72     mutable off_t disk_size;
  73
  74   public:
  75     RawDiskImage(const std::string &name, const std::string &filename,
  76                  bool rd_only);
  77     ~RawDiskImage();
  78
  79     void close();
  80     void open(const std::string &filename, bool rd_only = false);
  81
  82     virtual off_t size() const;
  83
  84     virtual off_t read(uint8_t *data, off_t offset) const;
  85     virtual off_t write(const uint8_t *data, off_t offset);
  86 };
  87
  88 /**
  89  * Specialization for accessing a copy-on-write disk image layer.
  90  * A copy-on-write(COW) layer must be stacked on top of another disk
  91  * image layer this layer can be another CowDiskImage, or a
  92  * RawDiskImage.
  93  *
  94  * This object is designed to provide a mechanism for persistant
  95  * changes to a main disk image, or to provide a place for temporary
  96  * changes to the image to take place that later may be thrown away.
  97  */
  98 class CowDiskImage : public DiskImage
  99 {
 100   public:
 101     static const int VersionMajor;
 102     static const int VersionMinor;
 103
 104   protected:
 105     struct Sector {
 106         uint8_t data[SectorSize];
 107     };
 108     typedef m5::hash_map<uint64_t, Sector *> SectorTable;
 109
 110   protected:
 111     std::string filename;
 112     DiskImage *child;
 113     SectorTable *table;
 114
 115   public:
 116     CowDiskImage(const std::string &name, DiskImage *kid, int hash_size);
 117     CowDiskImage(const std::string &name, DiskImage *kid, int hash_size,
 118                  const std::string &filename, bool read_only);
 119     ~CowDiskImage();
 120
 121     void init(int hash_size);
 122     bool open(const std::string &file);
 123     void save();
 124     void save(const std::string &file);
 125     void writeback();
 126     void serialize(std::ostream &os);
 127     void unserialize(Checkpoint *cp, const std::string &section);
 128
 129     virtual off_t size() const;
 130
 131     virtual off_t read(uint8_t *data, off_t offset) const;
 132     virtual off_t write(const uint8_t *data, off_t offset);
 133 };
 134
 135 #endif // __DISK_IMAGE_HH__