disk_image.hh revision 11169 
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#include <unordered_map>
40
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 */
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 std::streampos size() const = 0;
62
63    virtual std::streampos read(uint8_t *data,
64                                std::streampos offset) const = 0;
65    virtual std::streampos write(const uint8_t *data,
66                                 std::streampos offset) = 0;
67};
68
69/**
70 * Specialization for accessing a raw disk image
71 */
72class RawDiskImage : public DiskImage
73{
74  protected:
75    mutable std::fstream stream;
76    std::string file;
77    bool readonly;
78    mutable std::streampos disk_size;
79
80  public:
81    typedef RawDiskImageParams Params;
82    RawDiskImage(const Params *p);
83    ~RawDiskImage();
84
85    void close();
86    void open(const std::string &filename, bool rd_only = false);
87
88    virtual std::streampos size() const;
89
90    virtual std::streampos read(uint8_t *data, std::streampos offset) const;
91    virtual std::streampos write(const uint8_t *data, std::streampos offset);
92};
93
94/**
95 * Specialization for accessing a copy-on-write disk image layer.
96 * A copy-on-write(COW) layer must be stacked on top of another disk
97 * image layer this layer can be another CowDiskImage, or a
98 * RawDiskImage.
99 *
100 * This object is designed to provide a mechanism for persistant
101 * changes to a main disk image, or to provide a place for temporary
102 * changes to the image to take place that later may be thrown away.
103 */
104class CowDiskImage : public DiskImage
105{
106  public:
107    static const uint32_t VersionMajor;
108    static const uint32_t VersionMinor;
109
110  protected:
111    struct Sector {
112        uint8_t data[SectorSize];
113    };
114    typedef std::unordered_map<uint64_t, Sector *> SectorTable;
115
116  protected:
117    std::string filename;
118    DiskImage *child;
119    SectorTable *table;
120
121  public:
122    typedef CowDiskImageParams Params;
123    CowDiskImage(const Params *p);
124    ~CowDiskImage();
125
126    void initSectorTable(int hash_size);
127    bool open(const std::string &file);
128    void save() const;
129    void save(const std::string &file) const;
130    void writeback();
131
132    void serialize(CheckpointOut &cp) const override;
133    void unserialize(CheckpointIn &cp) override;
134
135    std::streampos size() const override;
136
137    std::streampos read(uint8_t *data, std::streampos offset) const override;
138    std::streampos write(const uint8_t *data, std::streampos offset) override;
139};
140
141void SafeRead(std::ifstream &stream, void *data, int count);
142
143template<class T>
144void SafeRead(std::ifstream &stream, T &data);
145
146template<class T>
147void SafeReadSwap(std::ifstream &stream, T &data);
148
149void SafeWrite(std::ofstream &stream, const void *data, int count);
150
151template<class T>
152void SafeWrite(std::ofstream &stream, const T &data);
153
154template<class T>
155void SafeWriteSwap(std::ofstream &stream, const T &data);
156
157#endif // __DISK_IMAGE_HH__
158