disk_image.cc

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· CC 代码 · 共 428 行

/*
 * Copyright (c) 2001, 2002, 2003, 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 *
 * Authors: Nathan L. Binkert
 */

/** @file
 * Disk Image Definitions
 */

#include <sys/types.h>
#include <sys/uio.h>
#include <errno.h>
#include <unistd.h>

#include <cstring>
#include <fstream>
#include <string>

#include "base/callback.hh"
#include "base/misc.hh"
#include "base/trace.hh"
#include "dev/disk_image.hh"
#include "sim/sim_exit.hh"
#include "sim/byteswap.hh"

using namespace std;

////////////////////////////////////////////////////////////////////////
//
// Raw Disk image
//
RawDiskImage::RawDiskImage(const Params* p)
    : DiskImage(p), disk_size(0)
{ open(p->image_file, p->read_only); }

RawDiskImage::~RawDiskImage()
{ close(); }

void
RawDiskImage::open(const string &filename, bool rd_only)
{
    if (!filename.empty()) {
        initialized = true;
        readonly = rd_only;
        file = filename;

        ios::openmode mode = ios::in | ios::binary;
        if (!readonly)
            mode |= ios::out;
        stream.open(file.c_str(), mode);
        if (!stream.is_open())
            panic("Error opening %s", filename);
    }
}

void
RawDiskImage::close()
{
    stream.close();
}

off_t
RawDiskImage::size() const
{
    if (disk_size == 0) {
        if (!stream.is_open())
            panic("file not open!\n");
        stream.seekg(0, ios::end);
        disk_size = stream.tellg();
    }

    return disk_size / SectorSize;
}

off_t
RawDiskImage::read(uint8_t *data, off_t offset) const
{
    if (!initialized)
        panic("RawDiskImage not initialized");

    if (!stream.is_open())
        panic("file not open!\n");

    if (stream.seekg(offset * SectorSize, ios::beg) < 0)
        panic("Could not seek to location in file");

    streampos pos = stream.tellg();
    stream.read((char *)data, SectorSize);

    DPRINTF(DiskImageRead, "read: offset=%d\n", (uint64_t)offset);
    DDUMP(DiskImageRead, data, SectorSize);

    return stream.tellg() - pos;
}

off_t
RawDiskImage::write(const uint8_t *data, off_t offset)
{
    if (!initialized)
        panic("RawDiskImage not initialized");

    if (readonly)
        panic("Cannot write to a read only disk image");

    if (!stream.is_open())
        panic("file not open!\n");

    if (stream.seekp(offset * SectorSize, ios::beg) < 0)
        panic("Could not seek to location in file");

    DPRINTF(DiskImageWrite, "write: offset=%d\n", (uint64_t)offset);
    DDUMP(DiskImageWrite, data, SectorSize);

    streampos pos = stream.tellp();
    stream.write((const char *)data, SectorSize);
    return stream.tellp() - pos;
}

RawDiskImage *
RawDiskImageParams::create()
{
    return new RawDiskImage(this);
}

////////////////////////////////////////////////////////////////////////
//
// Copy on Write Disk image
//
const int CowDiskImage::VersionMajor = 1;
const int CowDiskImage::VersionMinor = 0;

class CowDiskCallback : public Callback
{
  private:
    CowDiskImage *image;

  public:
    CowDiskCallback(CowDiskImage *i) : image(i) {}
    void process() { image->save(); delete this; }
};

CowDiskImage::CowDiskImage(const Params *p)
    : DiskImage(p), filename(p->image_file), child(p->child), table(NULL)
{
    if (filename.empty()) {
        init(p->table_size);
    } else {
        if (!open(filename)) {
            if (p->read_only)
                fatal("could not open read-only file");
            init(p->table_size);
        }

        if (!p->read_only)
            registerExitCallback(new CowDiskCallback(this));
    }
}

CowDiskImage::~CowDiskImage()
{
    SectorTable::iterator i = table->begin();
    SectorTable::iterator end = table->end();

    while (i != end) {
        delete (*i).second;
        ++i;
    }
}

void
SafeRead(ifstream &stream, void *data, int count)
{
    stream.read((char *)data, count);
    if (!stream.is_open())
        panic("file not open");

    if (stream.eof())
        panic("premature end-of-file");

    if (stream.bad() || stream.fail())
        panic("error reading cowdisk image");
}

template<class T>
void
SafeRead(ifstream &stream, T &data)
{
    SafeRead(stream, &data, sizeof(data));
}

template<class T>
void
SafeReadSwap(ifstream &stream, T &data)
{
    SafeRead(stream, &data, sizeof(data));
    data = letoh(data); //is this the proper byte order conversion?
}

bool
CowDiskImage::open(const string &file)
{
    ifstream stream(file.c_str());
    if (!stream.is_open())
        return false;

    if (stream.fail() || stream.bad())
        panic("Error opening %s", file);

    uint64_t magic;
    SafeRead(stream, magic);

    if (memcmp(&magic, "COWDISK!", sizeof(magic)) != 0)
        panic("Could not open %s: Invalid magic", file);

    uint32_t major, minor;
    SafeReadSwap(stream, major);
    SafeReadSwap(stream, minor);

    if (major != VersionMajor && minor != VersionMinor)
        panic("Could not open %s: invalid version %d.%d != %d.%d",
              file, major, minor, VersionMajor, VersionMinor);

    uint64_t sector_count;
    SafeReadSwap(stream, sector_count);
    table = new SectorTable(sector_count);


    for (uint64_t i = 0; i < sector_count; i++) {
        uint64_t offset;
        SafeReadSwap(stream, offset);

        Sector *sector = new Sector;
        SafeRead(stream, sector, sizeof(Sector));

        assert(table->find(offset) == table->end());
        (*table)[offset] = sector;
    }

    stream.close();

    initialized = true;
    return true;
}

void
CowDiskImage::init(int hash_size)
{
    table = new SectorTable(hash_size);

    initialized = true;
}

void
SafeWrite(ofstream &stream, const void *data, int count)
{
    stream.write((const char *)data, count);
    if (!stream.is_open())
        panic("file not open");

    if (stream.eof())
        panic("premature end-of-file");

    if (stream.bad() || stream.fail())
        panic("error reading cowdisk image");
}

template<class T>
void
SafeWrite(ofstream &stream, const T &data)
{
    SafeWrite(stream, &data, sizeof(data));
}

template<class T>
void
SafeWriteSwap(ofstream &stream, const T &data)
{
    T swappeddata = letoh(data); //is this the proper byte order conversion?
    SafeWrite(stream, &swappeddata, sizeof(data));
}
void
CowDiskImage::save()
{
    save(filename);
}

void
CowDiskImage::save(const string &file)
{
    if (!initialized)
        panic("RawDiskImage not initialized");

    ofstream stream(file.c_str());
    if (!stream.is_open() || stream.fail() || stream.bad())
        panic("Error opening %s", file);

    uint64_t magic;
    memcpy(&magic, "COWDISK!", sizeof(magic));
    SafeWrite(stream, magic);

    SafeWriteSwap(stream, (uint32_t)VersionMajor);
    SafeWriteSwap(stream, (uint32_t)VersionMinor);
    SafeWriteSwap(stream, (uint64_t)table->size());

    uint64_t size = table->size();
    SectorTable::iterator iter = table->begin();
    SectorTable::iterator end = table->end();

    for (uint64_t i = 0; i < size; i++) {
        if (iter == end)
            panic("Incorrect Table Size during save of COW disk image");

        SafeWriteSwap(stream, (uint64_t)(*iter).first);
        SafeWrite(stream, (*iter).second->data, sizeof(Sector));
        ++iter;
    }

    stream.close();
}

void
CowDiskImage::writeback()
{
    SectorTable::iterator i = table->begin();
    SectorTable::iterator end = table->end();

    while (i != end) {
        child->write((*i).second->data, (*i).first);
        ++i;
    }
}

off_t
CowDiskImage::size() const
{ return child->size(); }

off_t
CowDiskImage::read(uint8_t *data, off_t offset) const
{
    if (!initialized)
        panic("CowDiskImage not initialized");

    if (offset > size())
        panic("access out of bounds");

    SectorTable::const_iterator i = table->find(offset);
    if (i == table->end())
        return child->read(data, offset);
    else {
        memcpy(data, (*i).second->data, SectorSize);
        DPRINTF(DiskImageRead, "read: offset=%d\n", (uint64_t)offset);
        DDUMP(DiskImageRead, data, SectorSize);
        return SectorSize;
    }
}

off_t
CowDiskImage::write(const uint8_t *data, off_t offset)
{
    if (!initialized)
        panic("RawDiskImage not initialized");

    if (offset > size())
        panic("access out of bounds");

    SectorTable::iterator i = table->find(offset);
    if (i == table->end()) {
        Sector *sector = new Sector;
        memcpy(sector, data, SectorSize);
        table->insert(make_pair(offset, sector));
    } else {
        memcpy((*i).second->data, data, SectorSize);
    }

    DPRINTF(DiskImageWrite, "write: offset=%d\n", (uint64_t)offset);
    DDUMP(DiskImageWrite, data, SectorSize);

    return SectorSize;
}

void
CowDiskImage::serialize(ostream &os)
{
    string cowFilename = name() + ".cow";
    SERIALIZE_SCALAR(cowFilename);
    save(Checkpoint::dir() + "/" + cowFilename);
}

void
CowDiskImage::unserialize(Checkpoint *cp, const string &section)
{
    string cowFilename;
    UNSERIALIZE_SCALAR(cowFilename);
    cowFilename = cp->cptDir + "/" + cowFilename;
    open(cowFilename);
}

CowDiskImage *
CowDiskImageParams::create()
{
    return new CowDiskImage(this);
}