block/raw-win32.c

   1 /*
   2  * Block driver for RAW files (win32)
   3  *
   4  * Copyright (c) 2006 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu-common.h"
  25 #include "qemu/timer.h"
  26 #include "block/block_int.h"
  27 #include "qemu/module.h"
  28 #include "raw-aio.h"
  29 #include "trace.h"
  30 #include "block/thread-pool.h"
  31 #include "qemu/iov.h"
  32 #include <windows.h>
  33 #include <winioctl.h>
  34
  35 #define FTYPE_FILE 0
  36 #define FTYPE_CD     1
  37 #define FTYPE_HARDDISK 2
  38
  39 typedef struct RawWin32AIOData {
  40     BlockDriverState *bs;
  41     HANDLE hfile;
  42     struct iovec *aio_iov;
  43     int aio_niov;
  44     size_t aio_nbytes;
  45     off64_t aio_offset;
  46     int aio_type;
  47 } RawWin32AIOData;
  48
  49 typedef struct BDRVRawState {
  50     HANDLE hfile;
  51     int type;
  52     char drive_path[16]; /* format: "d:\" */
  53     QEMUWin32AIOState *aio;
  54 } BDRVRawState;
  55
  56 /*
  57  * Read/writes the data to/from a given linear buffer.
  58  *
  59  * Returns the number of bytes handles or -errno in case of an error. Short
  60  * reads are only returned if the end of the file is reached.
  61  */
  62 static size_t handle_aiocb_rw(RawWin32AIOData *aiocb)
  63 {
  64     size_t offset = 0;
  65     int i;
  66
  67     for (i = 0; i < aiocb->aio_niov; i++) {
  68         OVERLAPPED ov;
  69         DWORD ret, ret_count, len;
  70
  71         memset(&ov, 0, sizeof(ov));
  72         ov.Offset = (aiocb->aio_offset + offset);
  73         ov.OffsetHigh = (aiocb->aio_offset + offset) >> 32;
  74         len = aiocb->aio_iov[i].iov_len;
  75         if (aiocb->aio_type & QEMU_AIO_WRITE) {
  76             ret = WriteFile(aiocb->hfile, aiocb->aio_iov[i].iov_base,
  77                             len, &ret_count, &ov);
  78         } else {
  79             ret = ReadFile(aiocb->hfile, aiocb->aio_iov[i].iov_base,
  80                            len, &ret_count, &ov);
  81         }
  82         if (!ret) {
  83             ret_count = 0;
  84         }
  85         if (ret_count != len) {
  86             offset += ret_count;
  87             break;
  88         }
  89         offset += len;
  90     }
  91
  92     return offset;
  93 }
  94
  95 static int aio_worker(void *arg)
  96 {
  97     RawWin32AIOData *aiocb = arg;
  98     ssize_t ret = 0;
  99     size_t count;
 100
 101     switch (aiocb->aio_type & QEMU_AIO_TYPE_MASK) {
 102     case QEMU_AIO_READ:
 103         count = handle_aiocb_rw(aiocb);
 104         if (count < aiocb->aio_nbytes && aiocb->bs->growable) {
 105             /* A short read means that we have reached EOF. Pad the buffer
 106              * with zeros for bytes after EOF. */
 107             iov_memset(aiocb->aio_iov, aiocb->aio_niov, count,
 108                       0, aiocb->aio_nbytes - count);
 109
 110             count = aiocb->aio_nbytes;
 111         }
 112         if (count == aiocb->aio_nbytes) {
 113             ret = 0;
 114         } else {
 115             ret = -EINVAL;
 116         }
 117         break;
 118     case QEMU_AIO_WRITE:
 119         count = handle_aiocb_rw(aiocb);
 120         if (count == aiocb->aio_nbytes) {
 121             count = 0;
 122         } else {
 123             count = -EINVAL;
 124         }
 125         break;
 126     case QEMU_AIO_FLUSH:
 127         if (!FlushFileBuffers(aiocb->hfile)) {
 128             return -EIO;
 129         }
 130         break;
 131     default:
 132         fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type);
 133         ret = -EINVAL;
 134         break;
 135     }
 136
 137     g_slice_free(RawWin32AIOData, aiocb);
 138     return ret;
 139 }
 140
 141 static BlockDriverAIOCB *paio_submit(BlockDriverState *bs, HANDLE hfile,
 142         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 143         BlockDriverCompletionFunc *cb, void *opaque, int type)
 144 {
 145     RawWin32AIOData *acb = g_slice_new(RawWin32AIOData);
 146     ThreadPool *pool;
 147
 148     acb->bs = bs;
 149     acb->hfile = hfile;
 150     acb->aio_type = type;
 151
 152     if (qiov) {
 153         acb->aio_iov = qiov->iov;
 154         acb->aio_niov = qiov->niov;
 155     }
 156     acb->aio_nbytes = nb_sectors * 512;
 157     acb->aio_offset = sector_num * 512;
 158
 159     trace_paio_submit(acb, opaque, sector_num, nb_sectors, type);
 160     pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
 161     return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
 162 }
 163
 164 int qemu_ftruncate64(int fd, int64_t length)
 165 {
 166     LARGE_INTEGER li;
 167     DWORD dw;
 168     LONG high;
 169     HANDLE h;
 170     BOOL res;
 171
 172     if ((GetVersion() & 0x80000000UL) && (length >> 32) != 0)
 173         return -1;
 174
 175     h = (HANDLE)_get_osfhandle(fd);
 176
 177     /* get current position, ftruncate do not change position */
 178     li.HighPart = 0;
 179     li.LowPart = SetFilePointer (h, 0, &li.HighPart, FILE_CURRENT);
 180     if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
 181         return -1;
 182     }
 183
 184     high = length >> 32;
 185     dw = SetFilePointer(h, (DWORD) length, &high, FILE_BEGIN);
 186     if (dw == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
 187         return -1;
 188     }
 189     res = SetEndOfFile(h);
 190
 191     /* back to old position */
 192     SetFilePointer(h, li.LowPart, &li.HighPart, FILE_BEGIN);
 193     return res ? 0 : -1;
 194 }
 195
 196 static int set_sparse(int fd)
 197 {
 198     DWORD returned;
 199     return (int) DeviceIoControl((HANDLE)_get_osfhandle(fd), FSCTL_SET_SPARSE,
 200                                  NULL, 0, NULL, 0, &returned, NULL);
 201 }
 202
 203 static void raw_detach_aio_context(BlockDriverState *bs)
 204 {
 205     BDRVRawState *s = bs->opaque;
 206
 207     if (s->aio) {
 208         win32_aio_detach_aio_context(s->aio, bdrv_get_aio_context(bs));
 209     }
 210 }
 211
 212 static void raw_attach_aio_context(BlockDriverState *bs,
 213                                    AioContext *new_context)
 214 {
 215     BDRVRawState *s = bs->opaque;
 216
 217     if (s->aio) {
 218         win32_aio_attach_aio_context(s->aio, new_context);
 219     }
 220 }
 221
 222 static void raw_probe_alignment(BlockDriverState *bs)
 223 {
 224     BDRVRawState *s = bs->opaque;
 225     DWORD sectorsPerCluster, freeClusters, totalClusters, count;
 226     DISK_GEOMETRY_EX dg;
 227     BOOL status;
 228
 229     if (s->type == FTYPE_CD) {
 230         bs->request_alignment = 2048;
 231         return;
 232     }
 233     if (s->type == FTYPE_HARDDISK) {
 234         status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
 235                                  NULL, 0, &dg, sizeof(dg), &count, NULL);
 236         if (status != 0) {
 237             bs->request_alignment = dg.Geometry.BytesPerSector;
 238             return;
 239         }
 240         /* try GetDiskFreeSpace too */
 241     }
 242
 243     if (s->drive_path[0]) {
 244         GetDiskFreeSpace(s->drive_path, &sectorsPerCluster,
 245                          &dg.Geometry.BytesPerSector,
 246                          &freeClusters, &totalClusters);
 247         bs->request_alignment = dg.Geometry.BytesPerSector;
 248     }
 249 }
 250
 251 static void raw_parse_flags(int flags, int *access_flags, DWORD *overlapped)
 252 {
 253     assert(access_flags != NULL);
 254     assert(overlapped != NULL);
 255
 256     if (flags & BDRV_O_RDWR) {
 257         *access_flags = GENERIC_READ | GENERIC_WRITE;
 258     } else {
 259         *access_flags = GENERIC_READ;
 260     }
 261
 262     *overlapped = FILE_ATTRIBUTE_NORMAL;
 263     if (flags & BDRV_O_NATIVE_AIO) {
 264         *overlapped |= FILE_FLAG_OVERLAPPED;
 265     }
 266     if (flags & BDRV_O_NOCACHE) {
 267         *overlapped |= FILE_FLAG_NO_BUFFERING;
 268     }
 269 }
 270
 271 static void raw_parse_filename(const char *filename, QDict *options,
 272                                Error **errp)
 273 {
 274     /* The filename does not have to be prefixed by the protocol name, since
 275      * "file" is the default protocol; therefore, the return value of this
 276      * function call can be ignored. */
 277     strstart(filename, "file:", &filename);
 278
 279     qdict_put_obj(options, "filename", QOBJECT(qstring_from_str(filename)));
 280 }
 281
 282 static QemuOptsList raw_runtime_opts = {
 283     .name = "raw",
 284     .head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
 285     .desc = {
 286         {
 287             .name = "filename",
 288             .type = QEMU_OPT_STRING,
 289             .help = "File name of the image",
 290         },
 291         { /* end of list */ }
 292     },
 293 };
 294
 295 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 296                     Error **errp)
 297 {
 298     BDRVRawState *s = bs->opaque;
 299     int access_flags;
 300     DWORD overlapped;
 301     QemuOpts *opts;
 302     Error *local_err = NULL;
 303     const char *filename;
 304     int ret;
 305
 306     s->type = FTYPE_FILE;
 307
 308     opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
 309     qemu_opts_absorb_qdict(opts, options, &local_err);
 310     if (local_err) {
 311         error_propagate(errp, local_err);
 312         ret = -EINVAL;
 313         goto fail;
 314     }
 315
 316     filename = qemu_opt_get(opts, "filename");
 317
 318     raw_parse_flags(flags, &access_flags, &overlapped);
 319
 320     if (filename[0] && filename[1] == ':') {
 321         snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", filename[0]);
 322     } else if (filename[0] == '\\' && filename[1] == '\\') {
 323         s->drive_path[0] = 0;
 324     } else {
 325         /* Relative path.  */
 326         char buf[MAX_PATH];
 327         GetCurrentDirectory(MAX_PATH, buf);
 328         snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", buf[0]);
 329     }
 330
 331     s->hfile = CreateFile(filename, access_flags,
 332                           FILE_SHARE_READ, NULL,
 333                           OPEN_EXISTING, overlapped, NULL);
 334     if (s->hfile == INVALID_HANDLE_VALUE) {
 335         int err = GetLastError();
 336
 337         if (err == ERROR_ACCESS_DENIED) {
 338             ret = -EACCES;
 339         } else {
 340             ret = -EINVAL;
 341         }
 342         goto fail;
 343     }
 344
 345     if (flags & BDRV_O_NATIVE_AIO) {
 346         s->aio = win32_aio_init();
 347         if (s->aio == NULL) {
 348             CloseHandle(s->hfile);
 349             error_setg(errp, "Could not initialize AIO");
 350             ret = -EINVAL;
 351             goto fail;
 352         }
 353
 354         ret = win32_aio_attach(s->aio, s->hfile);
 355         if (ret < 0) {
 356             win32_aio_cleanup(s->aio);
 357             CloseHandle(s->hfile);
 358             error_setg_errno(errp, -ret, "Could not enable AIO");
 359             goto fail;
 360         }
 361
 362         win32_aio_attach_aio_context(s->aio, bdrv_get_aio_context(bs));
 363     }
 364
 365     raw_probe_alignment(bs);
 366     ret = 0;
 367 fail:
 368     qemu_opts_del(opts);
 369     return ret;
 370 }
 371
 372 static BlockDriverAIOCB *raw_aio_readv(BlockDriverState *bs,
 373                          int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 374                          BlockDriverCompletionFunc *cb, void *opaque)
 375 {
 376     BDRVRawState *s = bs->opaque;
 377     if (s->aio) {
 378         return win32_aio_submit(bs, s->aio, s->hfile, sector_num, qiov,
 379                                 nb_sectors, cb, opaque, QEMU_AIO_READ);
 380     } else {
 381         return paio_submit(bs, s->hfile, sector_num, qiov, nb_sectors,
 382                            cb, opaque, QEMU_AIO_READ);
 383     }
 384 }
 385
 386 static BlockDriverAIOCB *raw_aio_writev(BlockDriverState *bs,
 387                           int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 388                           BlockDriverCompletionFunc *cb, void *opaque)
 389 {
 390     BDRVRawState *s = bs->opaque;
 391     if (s->aio) {
 392         return win32_aio_submit(bs, s->aio, s->hfile, sector_num, qiov,
 393                                 nb_sectors, cb, opaque, QEMU_AIO_WRITE);
 394     } else {
 395         return paio_submit(bs, s->hfile, sector_num, qiov, nb_sectors,
 396                            cb, opaque, QEMU_AIO_WRITE);
 397     }
 398 }
 399
 400 static BlockDriverAIOCB *raw_aio_flush(BlockDriverState *bs,
 401                          BlockDriverCompletionFunc *cb, void *opaque)
 402 {
 403     BDRVRawState *s = bs->opaque;
 404     return paio_submit(bs, s->hfile, 0, NULL, 0, cb, opaque, QEMU_AIO_FLUSH);
 405 }
 406
 407 static void raw_close(BlockDriverState *bs)
 408 {
 409     BDRVRawState *s = bs->opaque;
 410
 411     if (s->aio) {
 412         win32_aio_detach_aio_context(s->aio, bdrv_get_aio_context(bs));
 413         win32_aio_cleanup(s->aio);
 414         s->aio = NULL;
 415     }
 416
 417     CloseHandle(s->hfile);
 418     if (bs->open_flags & BDRV_O_TEMPORARY) {
 419         unlink(bs->filename);
 420     }
 421 }
 422
 423 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 424 {
 425     BDRVRawState *s = bs->opaque;
 426     LONG low, high;
 427     DWORD dwPtrLow;
 428
 429     low = offset;
 430     high = offset >> 32;
 431
 432     /*
 433      * An error has occurred if the return value is INVALID_SET_FILE_POINTER
 434      * and GetLastError doesn't return NO_ERROR.
 435      */
 436     dwPtrLow = SetFilePointer(s->hfile, low, &high, FILE_BEGIN);
 437     if (dwPtrLow == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
 438         fprintf(stderr, "SetFilePointer error: %lu\n", GetLastError());
 439         return -EIO;
 440     }
 441     if (SetEndOfFile(s->hfile) == 0) {
 442         fprintf(stderr, "SetEndOfFile error: %lu\n", GetLastError());
 443         return -EIO;
 444     }
 445     return 0;
 446 }
 447
 448 static int64_t raw_getlength(BlockDriverState *bs)
 449 {
 450     BDRVRawState *s = bs->opaque;
 451     LARGE_INTEGER l;
 452     ULARGE_INTEGER available, total, total_free;
 453     DISK_GEOMETRY_EX dg;
 454     DWORD count;
 455     BOOL status;
 456
 457     switch(s->type) {
 458     case FTYPE_FILE:
 459         l.LowPart = GetFileSize(s->hfile, (PDWORD)&l.HighPart);
 460         if (l.LowPart == 0xffffffffUL && GetLastError() != NO_ERROR)
 461             return -EIO;
 462         break;
 463     case FTYPE_CD:
 464         if (!GetDiskFreeSpaceEx(s->drive_path, &available, &total, &total_free))
 465             return -EIO;
 466         l.QuadPart = total.QuadPart;
 467         break;
 468     case FTYPE_HARDDISK:
 469         status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
 470                                  NULL, 0, &dg, sizeof(dg), &count, NULL);
 471         if (status != 0) {
 472             l = dg.DiskSize;
 473         }
 474         break;
 475     default:
 476         return -EIO;
 477     }
 478     return l.QuadPart;
 479 }
 480
 481 static int64_t raw_get_allocated_file_size(BlockDriverState *bs)
 482 {
 483     typedef DWORD (WINAPI * get_compressed_t)(const char *filename,
 484                                               DWORD * high);
 485     get_compressed_t get_compressed;
 486     struct _stati64 st;
 487     const char *filename = bs->filename;
 488     /* WinNT support GetCompressedFileSize to determine allocate size */
 489     get_compressed =
 490         (get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"),
 491                                             "GetCompressedFileSizeA");
 492     if (get_compressed) {
 493         DWORD high, low;
 494         low = get_compressed(filename, &high);
 495         if (low != 0xFFFFFFFFlu || GetLastError() == NO_ERROR) {
 496             return (((int64_t) high) << 32) + low;
 497         }
 498     }
 499
 500     if (_stati64(filename, &st) < 0) {
 501         return -1;
 502     }
 503     return st.st_size;
 504 }
 505
 506 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 507 {
 508     int fd;
 509     int64_t total_size = 0;
 510
 511     strstart(filename, "file:", &filename);
 512
 513     /* Read out options */
 514     total_size =
 515         qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / 512;
 516
 517     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
 518                    0644);
 519     if (fd < 0) {
 520         error_setg_errno(errp, errno, "Could not create file");
 521         return -EIO;
 522     }
 523     set_sparse(fd);
 524     ftruncate(fd, total_size * 512);
 525     qemu_close(fd);
 526     return 0;
 527 }
 528
 529
 530 static QemuOptsList raw_create_opts = {
 531     .name = "raw-create-opts",
 532     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
 533     .desc = {
 534         {
 535             .name = BLOCK_OPT_SIZE,
 536             .type = QEMU_OPT_SIZE,
 537             .help = "Virtual disk size"
 538         },
 539         { /* end of list */ }
 540     }
 541 };
 542
 543 static BlockDriver bdrv_file = {
 544     .format_name        = "file",
 545     .protocol_name      = "file",
 546     .instance_size      = sizeof(BDRVRawState),
 547     .bdrv_needs_filename = true,
 548     .bdrv_parse_filename = raw_parse_filename,
 549     .bdrv_file_open     = raw_open,
 550     .bdrv_close         = raw_close,
 551     .bdrv_create        = raw_create,
 552     .bdrv_has_zero_init = bdrv_has_zero_init_1,
 553
 554     .bdrv_aio_readv     = raw_aio_readv,
 555     .bdrv_aio_writev    = raw_aio_writev,
 556     .bdrv_aio_flush     = raw_aio_flush,
 557
 558     .bdrv_truncate      = raw_truncate,
 559     .bdrv_getlength     = raw_getlength,
 560     .bdrv_get_allocated_file_size
 561                         = raw_get_allocated_file_size,
 562
 563     .create_opts        = &raw_create_opts,
 564 };
 565
 566 /***********************************************/
 567 /* host device */
 568
 569 static int find_cdrom(char *cdrom_name, int cdrom_name_size)
 570 {
 571     char drives[256], *pdrv = drives;
 572     UINT type;
 573
 574     memset(drives, 0, sizeof(drives));
 575     GetLogicalDriveStrings(sizeof(drives), drives);
 576     while(pdrv[0] != '\0') {
 577         type = GetDriveType(pdrv);
 578         switch(type) {
 579         case DRIVE_CDROM:
 580             snprintf(cdrom_name, cdrom_name_size, "\\\\.\\%c:", pdrv[0]);
 581             return 0;
 582             break;
 583         }
 584         pdrv += lstrlen(pdrv) + 1;
 585     }
 586     return -1;
 587 }
 588
 589 static int find_device_type(BlockDriverState *bs, const char *filename)
 590 {
 591     BDRVRawState *s = bs->opaque;
 592     UINT type;
 593     const char *p;
 594
 595     if (strstart(filename, "\\\\.\\", &p) ||
 596         strstart(filename, "//./", &p)) {
 597         if (stristart(p, "PhysicalDrive", NULL))
 598             return FTYPE_HARDDISK;
 599         snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", p[0]);
 600         type = GetDriveType(s->drive_path);
 601         switch (type) {
 602         case DRIVE_REMOVABLE:
 603         case DRIVE_FIXED:
 604             return FTYPE_HARDDISK;
 605         case DRIVE_CDROM:
 606             return FTYPE_CD;
 607         default:
 608             return FTYPE_FILE;
 609         }
 610     } else {
 611         return FTYPE_FILE;
 612     }
 613 }
 614
 615 static int hdev_probe_device(const char *filename)
 616 {
 617     if (strstart(filename, "/dev/cdrom", NULL))
 618         return 100;
 619     if (is_windows_drive(filename))
 620         return 100;
 621     return 0;
 622 }
 623
 624 static void hdev_parse_filename(const char *filename, QDict *options,
 625                                 Error **errp)
 626 {
 627     /* The prefix is optional, just as for "file". */
 628     strstart(filename, "host_device:", &filename);
 629
 630     qdict_put_obj(options, "filename", QOBJECT(qstring_from_str(filename)));
 631 }
 632
 633 static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
 634                      Error **errp)
 635 {
 636     BDRVRawState *s = bs->opaque;
 637     int access_flags, create_flags;
 638     int ret = 0;
 639     DWORD overlapped;
 640     char device_name[64];
 641
 642     Error *local_err = NULL;
 643     const char *filename;
 644
 645     QemuOpts *opts = qemu_opts_create(&raw_runtime_opts, NULL, 0,
 646                                       &error_abort);
 647     qemu_opts_absorb_qdict(opts, options, &local_err);
 648     if (local_err) {
 649         error_propagate(errp, local_err);
 650         ret = -EINVAL;
 651         goto done;
 652     }
 653
 654     filename = qemu_opt_get(opts, "filename");
 655
 656     if (strstart(filename, "/dev/cdrom", NULL)) {
 657         if (find_cdrom(device_name, sizeof(device_name)) < 0) {
 658             error_setg(errp, "Could not open CD-ROM drive");
 659             ret = -ENOENT;
 660             goto done;
 661         }
 662         filename = device_name;
 663     } else {
 664         /* transform drive letters into device name */
 665         if (((filename[0] >= 'a' && filename[0] <= 'z') ||
 666              (filename[0] >= 'A' && filename[0] <= 'Z')) &&
 667             filename[1] == ':' && filename[2] == '\0') {
 668             snprintf(device_name, sizeof(device_name), "\\\\.\\%c:", filename[0]);
 669             filename = device_name;
 670         }
 671     }
 672     s->type = find_device_type(bs, filename);
 673
 674     raw_parse_flags(flags, &access_flags, &overlapped);
 675
 676     create_flags = OPEN_EXISTING;
 677
 678     s->hfile = CreateFile(filename, access_flags,
 679                           FILE_SHARE_READ, NULL,
 680                           create_flags, overlapped, NULL);
 681     if (s->hfile == INVALID_HANDLE_VALUE) {
 682         int err = GetLastError();
 683
 684         if (err == ERROR_ACCESS_DENIED) {
 685             ret = -EACCES;
 686         } else {
 687             ret = -EINVAL;
 688         }
 689         error_setg_errno(errp, -ret, "Could not open device");
 690         goto done;
 691     }
 692
 693 done:
 694     qemu_opts_del(opts);
 695     return ret;
 696 }
 697
 698 static BlockDriver bdrv_host_device = {
 699     .format_name        = "host_device",
 700     .protocol_name      = "host_device",
 701     .instance_size      = sizeof(BDRVRawState),
 702     .bdrv_needs_filename = true,
 703     .bdrv_parse_filename = hdev_parse_filename,
 704     .bdrv_probe_device  = hdev_probe_device,
 705     .bdrv_file_open     = hdev_open,
 706     .bdrv_close         = raw_close,
 707
 708     .bdrv_aio_readv     = raw_aio_readv,
 709     .bdrv_aio_writev    = raw_aio_writev,
 710     .bdrv_aio_flush     = raw_aio_flush,
 711
 712     .bdrv_detach_aio_context = raw_detach_aio_context,
 713     .bdrv_attach_aio_context = raw_attach_aio_context,
 714
 715     .bdrv_getlength      = raw_getlength,
 716     .has_variable_length = true,
 717
 718     .bdrv_get_allocated_file_size
 719                         = raw_get_allocated_file_size,
 720 };
 721
 722 static void bdrv_file_init(void)
 723 {
 724     bdrv_register(&bdrv_file);
 725     bdrv_register(&bdrv_host_device);
 726 }
 727
 728 block_init(bdrv_file_init);