disk_image.hh revision 6227 
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#include "params/DiskImage.hh"
43#include "params/CowDiskImage.hh"
44#include "params/RawDiskImage.hh"
45
46#define SectorSize (512)
47
48/**
49 * Basic interface for accessing a disk image.
50 */
51class 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 */
70class 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 */
102class 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__
139