src/dev/storage/disk_image.cc

   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 Definitions
  33  */
  34
  35 #include "dev/storage/disk_image.hh"
  36
  37 #include <sys/types.h>
  38 #include <sys/uio.h>
  39 #include <unistd.h>
  40
  41 #include <cerrno>
  42 #include <cstring>
  43 #include <fstream>
  44 #include <string>
  45
  46 #include "base/callback.hh"
  47 #include "base/logging.hh"
  48 #include "base/trace.hh"
  49 #include "debug/DiskImageRead.hh"
  50 #include "debug/DiskImageWrite.hh"
  51 #include "sim/byteswap.hh"
  52 #include "sim/sim_exit.hh"
  53
  54 using namespace std;
  55
  56 ////////////////////////////////////////////////////////////////////////
  57 //
  58 // Raw Disk image
  59 //
  60 RawDiskImage::RawDiskImage(const Params* p)
  61     : DiskImage(p), disk_size(0)
  62 { open(p->image_file, p->read_only); }
  63
  64 RawDiskImage::~RawDiskImage()
  65 { close(); }
  66
  67 void
  68 RawDiskImage::notifyFork()
  69 {
  70     if (initialized && !readonly)
  71         panic("Attempting to fork system with read-write raw disk image.");
  72
  73     const Params *p(dynamic_cast<const Params *>(params()));
  74     close();
  75     open(p->image_file, p->read_only);
  76 }
  77
  78 void
  79 RawDiskImage::open(const string &filename, bool rd_only)
  80 {
  81     if (!filename.empty()) {
  82         initialized = true;
  83         readonly = rd_only;
  84         file = filename;
  85
  86         ios::openmode mode = ios::in | ios::binary;
  87         if (!readonly)
  88             mode |= ios::out;
  89         stream.open(file.c_str(), mode);
  90         if (!stream.is_open())
  91             panic("Error opening %s", filename);
  92     }
  93 }
  94
  95 void
  96 RawDiskImage::close()
  97 {
  98     stream.close();
  99 }
 100
 101 std::streampos
 102 RawDiskImage::size() const
 103 {
 104     if (disk_size == 0) {
 105         if (!stream.is_open())
 106             panic("file not open!\n");
 107         stream.seekg(0, ios::end);
 108         disk_size = stream.tellg();
 109     }
 110
 111     return disk_size / SectorSize;
 112 }
 113
 114 std::streampos
 115 RawDiskImage::read(uint8_t *data, std::streampos offset) const
 116 {
 117     if (!initialized)
 118         panic("RawDiskImage not initialized");
 119
 120     if (!stream.is_open())
 121         panic("file not open!\n");
 122
 123     stream.seekg(offset * SectorSize, ios::beg);
 124     if (!stream.good())
 125         panic("Could not seek to location in file");
 126
 127     streampos pos = stream.tellg();
 128     stream.read((char *)data, SectorSize);
 129
 130     DPRINTF(DiskImageRead, "read: offset=%d\n", (uint64_t)offset);
 131     DDUMP(DiskImageRead, data, SectorSize);
 132
 133     return stream.tellg() - pos;
 134 }
 135
 136 std::streampos
 137 RawDiskImage::write(const uint8_t *data, std::streampos offset)
 138 {
 139     if (!initialized)
 140         panic("RawDiskImage not initialized");
 141
 142     if (readonly)
 143         panic("Cannot write to a read only disk image");
 144
 145     if (!stream.is_open())
 146         panic("file not open!\n");
 147
 148     stream.seekp(offset * SectorSize, ios::beg);
 149     if (!stream.good())
 150         panic("Could not seek to location in file");
 151
 152     DPRINTF(DiskImageWrite, "write: offset=%d\n", (uint64_t)offset);
 153     DDUMP(DiskImageWrite, data, SectorSize);
 154
 155     streampos pos = stream.tellp();
 156     stream.write((const char *)data, SectorSize);
 157     return stream.tellp() - pos;
 158 }
 159
 160 RawDiskImage *
 161 RawDiskImageParams::create()
 162 {
 163     return new RawDiskImage(this);
 164 }
 165
 166 ////////////////////////////////////////////////////////////////////////
 167 //
 168 // Copy on Write Disk image
 169 //
 170 const uint32_t CowDiskImage::VersionMajor = 1;
 171 const uint32_t CowDiskImage::VersionMinor = 0;
 172
 173 class CowDiskCallback : public Callback
 174 {
 175   private:
 176     CowDiskImage *image;
 177
 178   public:
 179     CowDiskCallback(CowDiskImage *i) : image(i) {}
 180     void process() { image->save(); delete this; }
 181 };
 182
 183 CowDiskImage::CowDiskImage(const Params *p)
 184     : DiskImage(p), filename(p->image_file), child(p->child), table(NULL)
 185 {
 186     if (filename.empty()) {
 187         initSectorTable(p->table_size);
 188     } else {
 189         if (!open(filename)) {
 190             if (p->read_only)
 191                 fatal("could not open read-only file");
 192             initSectorTable(p->table_size);
 193         }
 194
 195         if (!p->read_only)
 196             registerExitCallback(new CowDiskCallback(this));
 197     }
 198 }
 199
 200 CowDiskImage::~CowDiskImage()
 201 {
 202     SectorTable::iterator i = table->begin();
 203     SectorTable::iterator end = table->end();
 204
 205     while (i != end) {
 206         delete (*i).second;
 207         ++i;
 208     }
 209 }
 210
 211 void
 212 CowDiskImage::notifyFork()
 213 {
 214     if (!dynamic_cast<const Params *>(params())->read_only &&
 215         !filename.empty()) {
 216         inform("Disabling saving of COW image in forked child process.\n");
 217         filename = "";
 218     }
 219 }
 220
 221 void
 222 SafeRead(ifstream &stream, void *data, int count)
 223 {
 224     stream.read((char *)data, count);
 225     if (!stream.is_open())
 226         panic("file not open");
 227
 228     if (stream.eof())
 229         panic("premature end-of-file");
 230
 231     if (stream.bad() || stream.fail())
 232         panic("error reading cowdisk image");
 233 }
 234
 235 template<class T>
 236 void
 237 SafeRead(ifstream &stream, T &data)
 238 {
 239     SafeRead(stream, &data, sizeof(data));
 240 }
 241
 242 template<class T>
 243 void
 244 SafeReadSwap(ifstream &stream, T &data)
 245 {
 246     SafeRead(stream, &data, sizeof(data));
 247     data = letoh(data); //is this the proper byte order conversion?
 248 }
 249
 250 bool
 251 CowDiskImage::open(const string &file)
 252 {
 253     ifstream stream(file.c_str());
 254     if (!stream.is_open())
 255         return false;
 256
 257     if (stream.fail() || stream.bad())
 258         panic("Error opening %s", file);
 259
 260     uint64_t magic;
 261     SafeRead(stream, magic);
 262
 263     if (memcmp(&magic, "COWDISK!", sizeof(magic)) != 0)
 264         panic("Could not open %s: Invalid magic", file);
 265
 266     uint32_t major, minor;
 267     SafeReadSwap(stream, major);
 268     SafeReadSwap(stream, minor);
 269
 270     if (major != VersionMajor && minor != VersionMinor)
 271         panic("Could not open %s: invalid version %d.%d != %d.%d",
 272               file, major, minor, VersionMajor, VersionMinor);
 273
 274     uint64_t sector_count;
 275     SafeReadSwap(stream, sector_count);
 276     table = new SectorTable(sector_count);
 277
 278
 279     for (uint64_t i = 0; i < sector_count; i++) {
 280         uint64_t offset;
 281         SafeReadSwap(stream, offset);
 282
 283         Sector *sector = new Sector;
 284         SafeRead(stream, sector, sizeof(Sector));
 285
 286         assert(table->find(offset) == table->end());
 287         (*table)[offset] = sector;
 288     }
 289
 290     stream.close();
 291
 292     initialized = true;
 293     return true;
 294 }
 295
 296 void
 297 CowDiskImage::initSectorTable(int hash_size)
 298 {
 299     table = new SectorTable(hash_size);
 300
 301     initialized = true;
 302 }
 303
 304 void
 305 SafeWrite(ofstream &stream, const void *data, int count)
 306 {
 307     stream.write((const char *)data, count);
 308     if (!stream.is_open())
 309         panic("file not open");
 310
 311     if (stream.eof())
 312         panic("premature end-of-file");
 313
 314     if (stream.bad() || stream.fail())
 315         panic("error reading cowdisk image");
 316 }
 317
 318 template<class T>
 319 void
 320 SafeWrite(ofstream &stream, const T &data)
 321 {
 322     SafeWrite(stream, &data, sizeof(data));
 323 }
 324
 325 template<class T>
 326 void
 327 SafeWriteSwap(ofstream &stream, const T &data)
 328 {
 329     T swappeddata = letoh(data); //is this the proper byte order conversion?
 330     SafeWrite(stream, &swappeddata, sizeof(data));
 331 }
 332 void
 333 CowDiskImage::save() const
 334 {
 335     // filename will be set to the empty string to disable saving of
 336     // the COW image in a forked child process. Save will still be
 337     // called because there is no easy way to unregister the exit
 338     // callback.
 339     if (!filename.empty())
 340         save(filename);}
 341
 342 void
 343 CowDiskImage::save(const string &file) const
 344 {
 345     if (!initialized)
 346         panic("RawDiskImage not initialized");
 347
 348     ofstream stream(file.c_str());
 349     if (!stream.is_open() || stream.fail() || stream.bad())
 350         panic("Error opening %s", file);
 351
 352     uint64_t magic;
 353     memcpy(&magic, "COWDISK!", sizeof(magic));
 354     SafeWrite(stream, magic);
 355
 356     SafeWriteSwap(stream, (uint32_t)VersionMajor);
 357     SafeWriteSwap(stream, (uint32_t)VersionMinor);
 358     SafeWriteSwap(stream, (uint64_t)table->size());
 359
 360     uint64_t size = table->size();
 361     SectorTable::iterator iter = table->begin();
 362     SectorTable::iterator end = table->end();
 363
 364     for (uint64_t i = 0; i < size; i++) {
 365         if (iter == end)
 366             panic("Incorrect Table Size during save of COW disk image");
 367
 368         SafeWriteSwap(stream, (uint64_t)(*iter).first);
 369         SafeWrite(stream, (*iter).second->data, sizeof(Sector));
 370         ++iter;
 371     }
 372
 373     stream.close();
 374 }
 375
 376 void
 377 CowDiskImage::writeback()
 378 {
 379     SectorTable::iterator i = table->begin();
 380     SectorTable::iterator end = table->end();
 381
 382     while (i != end) {
 383         child->write((*i).second->data, (*i).first);
 384         ++i;
 385     }
 386 }
 387
 388 std::streampos
 389 CowDiskImage::size() const
 390 { return child->size(); }
 391
 392 std::streampos
 393 CowDiskImage::read(uint8_t *data, std::streampos offset) const
 394 {
 395     if (!initialized)
 396         panic("CowDiskImage not initialized");
 397
 398     if (offset > size())
 399         panic("access out of bounds");
 400
 401     SectorTable::const_iterator i = table->find(offset);
 402     if (i == table->end())
 403         return child->read(data, offset);
 404     else {
 405         memcpy(data, (*i).second->data, SectorSize);
 406         DPRINTF(DiskImageRead, "read: offset=%d\n", (uint64_t)offset);
 407         DDUMP(DiskImageRead, data, SectorSize);
 408         return SectorSize;
 409     }
 410 }
 411
 412 std::streampos
 413 CowDiskImage::write(const uint8_t *data, std::streampos offset)
 414 {
 415     if (!initialized)
 416         panic("RawDiskImage not initialized");
 417
 418     if (offset > size())
 419         panic("access out of bounds");
 420
 421     SectorTable::iterator i = table->find(offset);
 422     if (i == table->end()) {
 423         Sector *sector = new Sector;
 424         memcpy(sector, data, SectorSize);
 425         table->insert(make_pair(offset, sector));
 426     } else {
 427         memcpy((*i).second->data, data, SectorSize);
 428     }
 429
 430     DPRINTF(DiskImageWrite, "write: offset=%d\n", (uint64_t)offset);
 431     DDUMP(DiskImageWrite, data, SectorSize);
 432
 433     return SectorSize;
 434 }
 435
 436 void
 437 CowDiskImage::serialize(CheckpointOut &cp) const
 438 {
 439     string cowFilename = name() + ".cow";
 440     SERIALIZE_SCALAR(cowFilename);
 441     save(CheckpointIn::dir() + "/" + cowFilename);
 442 }
 443
 444 void
 445 CowDiskImage::unserialize(CheckpointIn &cp)
 446 {
 447     string cowFilename;
 448     UNSERIALIZE_SCALAR(cowFilename);
 449     cowFilename = cp.cptDir + "/" + cowFilename;
 450     open(cowFilename);
 451 }
 452
 453 CowDiskImage *
 454 CowDiskImageParams::create()
 455 {
 456     return new CowDiskImage(this);
 457 }