disk_image.hh revision 2
1/* 2 * Copyright (c) 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 "hashmap.hh" 39#include "sim_object.hh" 40 41#define SectorSize (512) 42 43/* 44 * Basic interface for accessing a disk image. 45 */ 46class 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 */ 64class 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 */ 96class 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(); 121 void save(); 122 void writeback(); 123 124 virtual off_t size() const; 125 126 virtual off_t read(uint8_t *data, off_t offset) const; 127 virtual off_t write(const uint8_t *data, off_t offset); 128}; 129 130#endif // __DISK_IMAGE_HH__ 131