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
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   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,
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  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 Definitions
  31  */
  32
  33 #include "dev/storage/disk_image.hh"
  34
  35 #include <sys/types.h>
  36 #include <sys/uio.h>
  37 #include <unistd.h>
  38
  39 #include <cerrno>
  40 #include <cstring>
  41 #include <fstream>
  42 #include <string>
  43
  44 #include "base/callback.hh"
  45 #include "base/logging.hh"
  46 #include "base/trace.hh"
  47 #include "debug/DiskImageRead.hh"
  48 #include "debug/DiskImageWrite.hh"
  49 #include "sim/byteswap.hh"
  50 #include "sim/sim_exit.hh"
  51
  52 using namespace std;
  53
  54 ////////////////////////////////////////////////////////////////////////
  55 //
  56 // Raw Disk image
  57 //
  58 RawDiskImage::RawDiskImage(const Params &p)
  59     : DiskImage(p), disk_size(0)
  60 {
  61     open(p.image_file, p.read_only);
  62 }
  63
  64 RawDiskImage::~RawDiskImage()
  65 {
  66     close();
  67 }
  68
  69 void
  70 RawDiskImage::notifyFork()
  71 {
  72     if (initialized && !readonly)
  73         panic("Attempting to fork system with read-write raw disk image.");
  74
  75     const Params &p = dynamic_cast<const Params &>(params());
  76     close();
  77     open(p.image_file, p.read_only);
  78 }
  79
  80 void
  81 RawDiskImage::open(const string &filename, bool rd_only)
  82 {
  83     if (!filename.empty()) {
  84         initialized = true;
  85         readonly = rd_only;
  86         file = filename;
  87
  88         ios::openmode mode = ios::in | ios::binary;
  89         if (!readonly)
  90             mode |= ios::out;
  91         stream.open(file.c_str(), mode);
  92         if (!stream.is_open())
  93             panic("Error opening %s", filename);
  94     }
  95 }
  96
  97 void
  98 RawDiskImage::close()
  99 {
 100     stream.close();
 101 }
 102
 103 std::streampos
 104 RawDiskImage::size() const
 105 {
 106     if (disk_size == 0) {
 107         if (!stream.is_open())
 108             panic("file not open!\n");
 109         stream.seekg(0, ios::end);
 110         disk_size = stream.tellg();
 111     }
 112
 113     return disk_size / SectorSize;
 114 }
 115
 116 std::streampos
 117 RawDiskImage::read(uint8_t *data, std::streampos offset) const
 118 {
 119     if (!initialized)
 120         panic("RawDiskImage not initialized");
 121
 122     if (!stream.is_open())
 123         panic("file not open!\n");
 124
 125     stream.seekg(offset * SectorSize, ios::beg);
 126     if (!stream.good())
 127         panic("Could not seek to location in file");
 128
 129     streampos pos = stream.tellg();
 130     stream.read((char *)data, SectorSize);
 131
 132     DPRINTF(DiskImageRead, "read: offset=%d\n", (uint64_t)offset);
 133     DDUMP(DiskImageRead, data, SectorSize);
 134
 135     return stream.tellg() - pos;
 136 }
 137
 138 std::streampos
 139 RawDiskImage::write(const uint8_t *data, std::streampos offset)
 140 {
 141     if (!initialized)
 142         panic("RawDiskImage not initialized");
 143
 144     if (readonly)
 145         panic("Cannot write to a read only disk image");
 146
 147     if (!stream.is_open())
 148         panic("file not open!\n");
 149
 150     stream.seekp(offset * SectorSize, ios::beg);
 151     if (!stream.good())
 152         panic("Could not seek to location in file");
 153
 154     DPRINTF(DiskImageWrite, "write: offset=%d\n", (uint64_t)offset);
 155     DDUMP(DiskImageWrite, data, SectorSize);
 156
 157     streampos pos = stream.tellp();
 158     stream.write((const char *)data, SectorSize);
 159     return stream.tellp() - pos;
 160 }
 161
 162 ////////////////////////////////////////////////////////////////////////
 163 //
 164 // Copy on Write Disk image
 165 //
 166 const uint32_t CowDiskImage::VersionMajor = 1;
 167 const uint32_t CowDiskImage::VersionMinor = 0;
 168
 169 CowDiskImage::CowDiskImage(const Params &p)
 170     : DiskImage(p), filename(p.image_file), child(p.child), table(NULL)
 171 {
 172     if (filename.empty()) {
 173         initSectorTable(p.table_size);
 174     } else {
 175         if (!open(filename)) {
 176             if (p.read_only)
 177                 fatal("could not open read-only file");
 178             initSectorTable(p.table_size);
 179         }
 180
 181         if (!p.read_only)
 182             registerExitCallback([this]() { save(); });
 183     }
 184 }
 185
 186 CowDiskImage::~CowDiskImage()
 187 {
 188     SectorTable::iterator i = table->begin();
 189     SectorTable::iterator end = table->end();
 190
 191     while (i != end) {
 192         delete (*i).second;
 193         ++i;
 194     }
 195 }
 196
 197 void
 198 CowDiskImage::notifyFork()
 199 {
 200     if (!dynamic_cast<const Params &>(params()).read_only &&
 201         !filename.empty()) {
 202         inform("Disabling saving of COW image in forked child process.\n");
 203         filename = "";
 204     }
 205 }
 206
 207 void
 208 SafeRead(ifstream &stream, void *data, int count)
 209 {
 210     stream.read((char *)data, count);
 211     if (!stream.is_open())
 212         panic("file not open");
 213
 214     if (stream.eof())
 215         panic("premature end-of-file");
 216
 217     if (stream.bad() || stream.fail())
 218         panic("error reading cowdisk image");
 219 }
 220
 221 template<class T>
 222 void
 223 SafeRead(ifstream &stream, T &data)
 224 {
 225     SafeRead(stream, &data, sizeof(data));
 226 }
 227
 228 template<class T>
 229 void
 230 SafeReadSwap(ifstream &stream, T &data)
 231 {
 232     SafeRead(stream, &data, sizeof(data));
 233     data = letoh(data); //is this the proper byte order conversion?
 234 }
 235
 236 bool
 237 CowDiskImage::open(const string &file)
 238 {
 239     ifstream stream(file.c_str());
 240     if (!stream.is_open())
 241         return false;
 242
 243     if (stream.fail() || stream.bad())
 244         panic("Error opening %s", file);
 245
 246     uint64_t magic;
 247     SafeRead(stream, magic);
 248
 249     if (memcmp(&magic, "COWDISK!", sizeof(magic)) != 0)
 250         panic("Could not open %s: Invalid magic", file);
 251
 252     uint32_t major, minor;
 253     SafeReadSwap(stream, major);
 254     SafeReadSwap(stream, minor);
 255
 256     if (major != VersionMajor && minor != VersionMinor)
 257         panic("Could not open %s: invalid version %d.%d != %d.%d",
 258               file, major, minor, VersionMajor, VersionMinor);
 259
 260     uint64_t sector_count;
 261     SafeReadSwap(stream, sector_count);
 262     table = new SectorTable(sector_count);
 263
 264
 265     for (uint64_t i = 0; i < sector_count; i++) {
 266         uint64_t offset;
 267         SafeReadSwap(stream, offset);
 268
 269         Sector *sector = new Sector;
 270         SafeRead(stream, sector, sizeof(Sector));
 271
 272         assert(table->find(offset) == table->end());
 273         (*table)[offset] = sector;
 274     }
 275
 276     stream.close();
 277
 278     initialized = true;
 279     return true;
 280 }
 281
 282 void
 283 CowDiskImage::initSectorTable(int hash_size)
 284 {
 285     table = new SectorTable(hash_size);
 286
 287     initialized = true;
 288 }
 289
 290 void
 291 SafeWrite(ofstream &stream, const void *data, int count)
 292 {
 293     stream.write((const char *)data, count);
 294     if (!stream.is_open())
 295         panic("file not open");
 296
 297     if (stream.eof())
 298         panic("premature end-of-file");
 299
 300     if (stream.bad() || stream.fail())
 301         panic("error reading cowdisk image");
 302 }
 303
 304 template<class T>
 305 void
 306 SafeWrite(ofstream &stream, const T &data)
 307 {
 308     SafeWrite(stream, &data, sizeof(data));
 309 }
 310
 311 template<class T>
 312 void
 313 SafeWriteSwap(ofstream &stream, const T &data)
 314 {
 315     T swappeddata = letoh(data); //is this the proper byte order conversion?
 316     SafeWrite(stream, &swappeddata, sizeof(data));
 317 }
 318 void
 319 CowDiskImage::save() const
 320 {
 321     // filename will be set to the empty string to disable saving of
 322     // the COW image in a forked child process. Save will still be
 323     // called because there is no easy way to unregister the exit
 324     // callback.
 325     if (!filename.empty())
 326         save(filename);}
 327
 328 void
 329 CowDiskImage::save(const string &file) const
 330 {
 331     if (!initialized)
 332         panic("RawDiskImage not initialized");
 333
 334     ofstream stream(file.c_str());
 335     if (!stream.is_open() || stream.fail() || stream.bad())
 336         panic("Error opening %s", file);
 337
 338     uint64_t magic;
 339     memcpy(&magic, "COWDISK!", sizeof(magic));
 340     SafeWrite(stream, magic);
 341
 342     SafeWriteSwap(stream, (uint32_t)VersionMajor);
 343     SafeWriteSwap(stream, (uint32_t)VersionMinor);
 344     SafeWriteSwap(stream, (uint64_t)table->size());
 345
 346     uint64_t size = table->size();
 347     SectorTable::iterator iter = table->begin();
 348     SectorTable::iterator end = table->end();
 349
 350     for (uint64_t i = 0; i < size; i++) {
 351         if (iter == end)
 352             panic("Incorrect Table Size during save of COW disk image");
 353
 354         SafeWriteSwap(stream, (uint64_t)(*iter).first);
 355         SafeWrite(stream, (*iter).second->data, sizeof(Sector));
 356         ++iter;
 357     }
 358
 359     stream.close();
 360 }
 361
 362 void
 363 CowDiskImage::writeback()
 364 {
 365     SectorTable::iterator i = table->begin();
 366     SectorTable::iterator end = table->end();
 367
 368     while (i != end) {
 369         child->write((*i).second->data, (*i).first);
 370         ++i;
 371     }
 372 }
 373
 374 std::streampos
 375 CowDiskImage::size() const
 376 { return child->size(); }
 377
 378 std::streampos
 379 CowDiskImage::read(uint8_t *data, std::streampos offset) const
 380 {
 381     if (!initialized)
 382         panic("CowDiskImage not initialized");
 383
 384     if (offset > size())
 385         panic("access out of bounds");
 386
 387     SectorTable::const_iterator i = table->find(offset);
 388     if (i == table->end())
 389         return child->read(data, offset);
 390     else {
 391         memcpy(data, (*i).second->data, SectorSize);
 392         DPRINTF(DiskImageRead, "read: offset=%d\n", (uint64_t)offset);
 393         DDUMP(DiskImageRead, data, SectorSize);
 394         return SectorSize;
 395     }
 396 }
 397
 398 std::streampos
 399 CowDiskImage::write(const uint8_t *data, std::streampos offset)
 400 {
 401     if (!initialized)
 402         panic("RawDiskImage not initialized");
 403
 404     if (offset > size())
 405         panic("access out of bounds");
 406
 407     SectorTable::iterator i = table->find(offset);
 408     if (i == table->end()) {
 409         Sector *sector = new Sector;
 410         memcpy(sector, data, SectorSize);
 411         table->insert(make_pair(offset, sector));
 412     } else {
 413         memcpy((*i).second->data, data, SectorSize);
 414     }
 415
 416     DPRINTF(DiskImageWrite, "write: offset=%d\n", (uint64_t)offset);
 417     DDUMP(DiskImageWrite, data, SectorSize);
 418
 419     return SectorSize;
 420 }
 421
 422 void
 423 CowDiskImage::serialize(CheckpointOut &cp) const
 424 {
 425     string cowFilename = name() + ".cow";
 426     SERIALIZE_SCALAR(cowFilename);
 427     save(CheckpointIn::dir() + "/" + cowFilename);
 428 }
 429
 430 void
 431 CowDiskImage::unserialize(CheckpointIn &cp)
 432 {
 433     string cowFilename;
 434     UNSERIALIZE_SCALAR(cowFilename);
 435     cowFilename = cp.getCptDir() + "/" + cowFilename;
 436     open(cowFilename);
 437 }