disk_image.hh revision 2665 
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 */
48class 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 */
66class 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 */
98class 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__
136