qemu/block.c

   1 /*
   2  * QEMU System Emulator block driver
   3  *
   4  * Copyright (c) 2003 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 "config-host.h"
  25 #ifdef _BSD
  26 /* include native header before sys-queue.h */
  27 #include <sys/queue.h>
  28 #endif
  29
  30 #include "qemu-common.h"
  31 #include "console.h"
  32 #include "block_int.h"
  33 #include "osdep.h"
  34
  35 #ifdef _BSD
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <sys/ioctl.h>
  39 #include <sys/disk.h>
  40 #endif
  41
  42 #define SECTOR_BITS 9
  43 #define SECTOR_SIZE (1 << SECTOR_BITS)
  44
  45 typedef struct BlockDriverAIOCBSync {
  46     BlockDriverAIOCB common;
  47     QEMUBH *bh;
  48     int ret;
  49 } BlockDriverAIOCBSync;
  50
  51 static BlockDriverAIOCB *bdrv_aio_read_em(BlockDriverState *bs,
  52         int64_t sector_num, uint8_t *buf, int nb_sectors,
  53         BlockDriverCompletionFunc *cb, void *opaque);
  54 static BlockDriverAIOCB *bdrv_aio_write_em(BlockDriverState *bs,
  55         int64_t sector_num, const uint8_t *buf, int nb_sectors,
  56         BlockDriverCompletionFunc *cb, void *opaque);
  57 static void bdrv_aio_cancel_em(BlockDriverAIOCB *acb);
  58 static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
  59                         uint8_t *buf, int nb_sectors);
  60 static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
  61                          const uint8_t *buf, int nb_sectors);
  62
  63 BlockDriverState *bdrv_first;
  64
  65 static BlockDriver *first_drv;
  66
  67 int path_is_absolute(const char *path)
  68 {
  69     const char *p;
  70 #ifdef _WIN32
  71     /* specific case for names like: "\\.\d:" */
  72     if (*path == '/' || *path == '\\')
  73         return 1;
  74 #endif
  75     p = strchr(path, ':');
  76     if (p)
  77         p++;
  78     else
  79         p = path;
  80 #ifdef _WIN32
  81     return (*p == '/' || *p == '\\');
  82 #else
  83     return (*p == '/');
  84 #endif
  85 }
  86
  87 /* if filename is absolute, just copy it to dest. Otherwise, build a
  88    path to it by considering it is relative to base_path. URL are
  89    supported. */
  90 void path_combine(char *dest, int dest_size,
  91                   const char *base_path,
  92                   const char *filename)
  93 {
  94     const char *p, *p1;
  95     int len;
  96
  97     if (dest_size <= 0)
  98         return;
  99     if (path_is_absolute(filename)) {
 100         pstrcpy(dest, dest_size, filename);
 101     } else {
 102         p = strchr(base_path, ':');
 103         if (p)
 104             p++;
 105         else
 106             p = base_path;
 107         p1 = strrchr(base_path, '/');
 108 #ifdef _WIN32
 109         {
 110             const char *p2;
 111             p2 = strrchr(base_path, '\\');
 112             if (!p1 || p2 > p1)
 113                 p1 = p2;
 114         }
 115 #endif
 116         if (p1)
 117             p1++;
 118         else
 119             p1 = base_path;
 120         if (p1 > p)
 121             p = p1;
 122         len = p - base_path;
 123         if (len > dest_size - 1)
 124             len = dest_size - 1;
 125         memcpy(dest, base_path, len);
 126         dest[len] = '\0';
 127         pstrcat(dest, dest_size, filename);
 128     }
 129 }
 130
 131
 132 static void bdrv_register(BlockDriver *bdrv)
 133 {
 134     if (!bdrv->bdrv_aio_read) {
 135         /* add AIO emulation layer */
 136         bdrv->bdrv_aio_read = bdrv_aio_read_em;
 137         bdrv->bdrv_aio_write = bdrv_aio_write_em;
 138         bdrv->bdrv_aio_cancel = bdrv_aio_cancel_em;
 139         bdrv->aiocb_size = sizeof(BlockDriverAIOCBSync);
 140     } else if (!bdrv->bdrv_read && !bdrv->bdrv_pread) {
 141         /* add synchronous IO emulation layer */
 142         bdrv->bdrv_read = bdrv_read_em;
 143         bdrv->bdrv_write = bdrv_write_em;
 144     }
 145     bdrv->next = first_drv;
 146     first_drv = bdrv;
 147 }
 148
 149 /* create a new block device (by default it is empty) */
 150 BlockDriverState *bdrv_new(const char *device_name)
 151 {
 152     BlockDriverState **pbs, *bs;
 153
 154     bs = qemu_mallocz(sizeof(BlockDriverState));
 155     if(!bs)
 156         return NULL;
 157     pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
 158     if (device_name[0] != '\0') {
 159         /* insert at the end */
 160         pbs = &bdrv_first;
 161         while (*pbs != NULL)
 162             pbs = &(*pbs)->next;
 163         *pbs = bs;
 164     }
 165     return bs;
 166 }
 167
 168 BlockDriver *bdrv_find_format(const char *format_name)
 169 {
 170     BlockDriver *drv1;
 171     for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
 172         if (!strcmp(drv1->format_name, format_name))
 173             return drv1;
 174     }
 175     return NULL;
 176 }
 177
 178 int bdrv_create(BlockDriver *drv,
 179                 const char *filename, int64_t size_in_sectors,
 180                 const char *backing_file, int flags)
 181 {
 182     if (!drv->bdrv_create)
 183         return -ENOTSUP;
 184     return drv->bdrv_create(filename, size_in_sectors, backing_file, flags);
 185 }
 186
 187 #ifdef _WIN32
 188 void get_tmp_filename(char *filename, int size)
 189 {
 190     char temp_dir[MAX_PATH];
 191
 192     GetTempPath(MAX_PATH, temp_dir);
 193     GetTempFileName(temp_dir, "qem", 0, filename);
 194 }
 195 #else
 196 void get_tmp_filename(char *filename, int size)
 197 {
 198     int fd;
 199     const char *tmpdir;
 200     /* XXX: race condition possible */
 201     tmpdir = getenv("TMPDIR");
 202     if (!tmpdir)
 203         tmpdir = "/tmp";
 204     snprintf(filename, size, "%s/vl.XXXXXX", tmpdir);
 205     fd = mkstemp(filename);
 206     close(fd);
 207 }
 208 #endif
 209
 210 #ifdef _WIN32
 211 static int is_windows_drive_prefix(const char *filename)
 212 {
 213     return (((filename[0] >= 'a' && filename[0] <= 'z') ||
 214              (filename[0] >= 'A' && filename[0] <= 'Z')) &&
 215             filename[1] == ':');
 216 }
 217
 218 static int is_windows_drive(const char *filename)
 219 {
 220     if (is_windows_drive_prefix(filename) &&
 221         filename[2] == '\0')
 222         return 1;
 223     if (strstart(filename, "\\\\.\\", NULL) ||
 224         strstart(filename, "//./", NULL))
 225         return 1;
 226     return 0;
 227 }
 228 #endif
 229
 230 static BlockDriver *find_protocol(const char *filename)
 231 {
 232     BlockDriver *drv1;
 233     char protocol[128];
 234     int len;
 235     const char *p;
 236
 237 #ifdef _WIN32
 238     if (is_windows_drive(filename) ||
 239         is_windows_drive_prefix(filename))
 240         return &bdrv_raw;
 241 #endif
 242     p = strchr(filename, ':');
 243     if (!p)
 244         return &bdrv_raw;
 245     len = p - filename;
 246     if (len > sizeof(protocol) - 1)
 247         len = sizeof(protocol) - 1;
 248     memcpy(protocol, filename, len);
 249     protocol[len] = '\0';
 250     for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
 251         if (drv1->protocol_name &&
 252             !strcmp(drv1->protocol_name, protocol))
 253             return drv1;
 254     }
 255     return NULL;
 256 }
 257
 258 /* XXX: force raw format if block or character device ? It would
 259    simplify the BSD case */
 260 static BlockDriver *find_image_format(const char *filename)
 261 {
 262     int ret, score, score_max;
 263     BlockDriver *drv1, *drv;
 264     uint8_t buf[2048];
 265     BlockDriverState *bs;
 266
 267     /* detect host devices. By convention, /dev/cdrom[N] is always
 268        recognized as a host CDROM */
 269     if (strstart(filename, "/dev/cdrom", NULL))
 270         return &bdrv_host_device;
 271 #ifdef _WIN32
 272     if (is_windows_drive(filename))
 273         return &bdrv_host_device;
 274 #else
 275     {
 276         struct stat st;
 277         if (stat(filename, &st) >= 0 &&
 278             (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
 279             return &bdrv_host_device;
 280         }
 281     }
 282 #endif
 283
 284     drv = find_protocol(filename);
 285     /* no need to test disk image formats for vvfat */
 286     if (drv == &bdrv_vvfat)
 287         return drv;
 288
 289     ret = bdrv_file_open(&bs, filename, BDRV_O_RDONLY);
 290     if (ret < 0)
 291         return NULL;
 292     ret = bdrv_pread(bs, 0, buf, sizeof(buf));
 293     bdrv_delete(bs);
 294     if (ret < 0) {
 295         return NULL;
 296     }
 297
 298     score_max = 0;
 299     for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
 300         if (drv1->bdrv_probe) {
 301             score = drv1->bdrv_probe(buf, ret, filename);
 302             if (score > score_max) {
 303                 score_max = score;
 304                 drv = drv1;
 305             }
 306         }
 307     }
 308     return drv;
 309 }
 310
 311 int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
 312 {
 313     BlockDriverState *bs;
 314     int ret;
 315
 316     bs = bdrv_new("");
 317     if (!bs)
 318         return -ENOMEM;
 319     ret = bdrv_open2(bs, filename, flags | BDRV_O_FILE, NULL);
 320     if (ret < 0) {
 321         bdrv_delete(bs);
 322         return ret;
 323     }
 324     *pbs = bs;
 325     return 0;
 326 }
 327
 328 int bdrv_open(BlockDriverState *bs, const char *filename, int flags)
 329 {
 330     return bdrv_open2(bs, filename, flags, NULL);
 331 }
 332
 333 int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
 334                BlockDriver *drv)
 335 {
 336     int ret, open_flags;
 337     char tmp_filename[PATH_MAX];
 338     char backing_filename[PATH_MAX];
 339
 340     bs->read_only = 0;
 341     bs->is_temporary = 0;
 342     bs->encrypted = 0;
 343
 344     if (flags & BDRV_O_SNAPSHOT) {
 345         BlockDriverState *bs1;
 346         int64_t total_size;
 347         int is_protocol = 0;
 348
 349         /* if snapshot, we create a temporary backing file and open it
 350            instead of opening 'filename' directly */
 351
 352         /* if there is a backing file, use it */
 353         bs1 = bdrv_new("");
 354         if (!bs1) {
 355             return -ENOMEM;
 356         }
 357         if (bdrv_open(bs1, filename, 0) < 0) {
 358             bdrv_delete(bs1);
 359             return -1;
 360         }
 361         total_size = bdrv_getlength(bs1) >> SECTOR_BITS;
 362
 363         if (bs1->drv && bs1->drv->protocol_name)
 364             is_protocol = 1;
 365
 366         bdrv_delete(bs1);
 367
 368         get_tmp_filename(tmp_filename, sizeof(tmp_filename));
 369
 370         /* Real path is meaningless for protocols */
 371         if (is_protocol)
 372             snprintf(backing_filename, sizeof(backing_filename),
 373                      "%s", filename);
 374         else
 375             realpath(filename, backing_filename);
 376
 377         if (bdrv_create(&bdrv_qcow2, tmp_filename,
 378                         total_size, backing_filename, 0) < 0) {
 379             return -1;
 380         }
 381         filename = tmp_filename;
 382         bs->is_temporary = 1;
 383     }
 384
 385     pstrcpy(bs->filename, sizeof(bs->filename), filename);
 386     if (flags & BDRV_O_FILE) {
 387         drv = find_protocol(filename);
 388         if (!drv)
 389             return -ENOENT;
 390     } else {
 391         if (!drv) {
 392             drv = find_image_format(filename);
 393             if (!drv)
 394                 return -1;
 395         }
 396     }
 397     bs->drv = drv;
 398     bs->opaque = qemu_mallocz(drv->instance_size);
 399     if (bs->opaque == NULL && drv->instance_size > 0)
 400         return -1;
 401     /* Note: for compatibility, we open disk image files as RDWR, and
 402        RDONLY as fallback */
 403     if (!(flags & BDRV_O_FILE))
 404         open_flags = BDRV_O_RDWR | (flags & BDRV_O_CACHE_MASK);
 405     else
 406         open_flags = flags & ~(BDRV_O_FILE | BDRV_O_SNAPSHOT);
 407     ret = drv->bdrv_open(bs, filename, open_flags);
 408     if ((ret == -EACCES || ret == -EPERM) && !(flags & BDRV_O_FILE)) {
 409         ret = drv->bdrv_open(bs, filename, open_flags & ~BDRV_O_RDWR);
 410         bs->read_only = 1;
 411     }
 412     if (ret < 0) {
 413         qemu_free(bs->opaque);
 414         bs->opaque = NULL;
 415         bs->drv = NULL;
 416         return ret;
 417     }
 418     if (drv->bdrv_getlength) {
 419         bs->total_sectors = bdrv_getlength(bs) >> SECTOR_BITS;
 420     }
 421 #ifndef _WIN32
 422     if (bs->is_temporary) {
 423         unlink(filename);
 424     }
 425 #endif
 426     if (bs->backing_file[0] != '\0') {
 427         /* if there is a backing file, use it */
 428         bs->backing_hd = bdrv_new("");
 429         if (!bs->backing_hd) {
 430         fail:
 431             bdrv_close(bs);
 432             return -ENOMEM;
 433         }
 434         path_combine(backing_filename, sizeof(backing_filename),
 435                      filename, bs->backing_file);
 436         if (bdrv_open(bs->backing_hd, backing_filename, open_flags) < 0)
 437             goto fail;
 438     }
 439
 440     /* call the change callback */
 441     bs->media_changed = 1;
 442     if (bs->change_cb)
 443         bs->change_cb(bs->change_opaque);
 444
 445     return 0;
 446 }
 447
 448 void bdrv_close(BlockDriverState *bs)
 449 {
 450     if (bs->drv) {
 451         if (bs->backing_hd)
 452             bdrv_delete(bs->backing_hd);
 453         bs->drv->bdrv_close(bs);
 454         qemu_free(bs->opaque);
 455 #ifdef _WIN32
 456         if (bs->is_temporary) {
 457             unlink(bs->filename);
 458         }
 459 #endif
 460         bs->opaque = NULL;
 461         bs->drv = NULL;
 462
 463         /* call the change callback */
 464         bs->media_changed = 1;
 465         if (bs->change_cb)
 466             bs->change_cb(bs->change_opaque);
 467     }
 468 }
 469
 470 void bdrv_delete(BlockDriverState *bs)
 471 {
 472     BlockDriverState **pbs;
 473
 474     pbs = &bdrv_first;
 475     while (*pbs != bs && *pbs != NULL)
 476         pbs = &(*pbs)->next;
 477     if (*pbs == bs)
 478         *pbs = bs->next;
 479
 480     bdrv_close(bs);
 481     qemu_free(bs);
 482 }
 483
 484 /* commit COW file into the raw image */
 485 int bdrv_commit(BlockDriverState *bs)
 486 {
 487     BlockDriver *drv = bs->drv;
 488     int64_t i, total_sectors;
 489     int n, j;
 490     unsigned char sector[512];
 491
 492     if (!drv)
 493         return -ENOMEDIUM;
 494
 495     if (bs->read_only) {
 496         return -EACCES;
 497     }
 498
 499     if (!bs->backing_hd) {
 500         return -ENOTSUP;
 501     }
 502
 503     total_sectors = bdrv_getlength(bs) >> SECTOR_BITS;
 504     for (i = 0; i < total_sectors;) {
 505         if (drv->bdrv_is_allocated(bs, i, 65536, &n)) {
 506             for(j = 0; j < n; j++) {
 507                 if (bdrv_read(bs, i, sector, 1) != 0) {
 508                     return -EIO;
 509                 }
 510
 511                 if (bdrv_write(bs->backing_hd, i, sector, 1) != 0) {
 512                     return -EIO;
 513                 }
 514                 i++;
 515             }
 516         } else {
 517             i += n;
 518         }
 519     }
 520
 521     if (drv->bdrv_make_empty)
 522         return drv->bdrv_make_empty(bs);
 523
 524     return 0;
 525 }
 526
 527 /* return < 0 if error. See bdrv_write() for the return codes */
 528 int bdrv_read(BlockDriverState *bs, int64_t sector_num,
 529               uint8_t *buf, int nb_sectors)
 530 {
 531     BlockDriver *drv = bs->drv;
 532
 533     if (!drv)
 534         return -ENOMEDIUM;
 535
 536     if (drv->bdrv_pread) {
 537         int ret, len;
 538         len = nb_sectors * 512;
 539         ret = drv->bdrv_pread(bs, sector_num * 512, buf, len);
 540         if (ret < 0)
 541             return ret;
 542         else if (ret != len)
 543             return -EINVAL;
 544         else {
 545             bs->rd_bytes += (unsigned) len;
 546             bs->rd_ops ++;
 547             return 0;
 548         }
 549     } else {
 550         return drv->bdrv_read(bs, sector_num, buf, nb_sectors);
 551     }
 552 }
 553
 554 /* Return < 0 if error. Important errors are:
 555   -EIO         generic I/O error (may happen for all errors)
 556   -ENOMEDIUM   No media inserted.
 557   -EINVAL      Invalid sector number or nb_sectors
 558   -EACCES      Trying to write a read-only device
 559 */
 560 int bdrv_write(BlockDriverState *bs, int64_t sector_num,
 561                const uint8_t *buf, int nb_sectors)
 562 {
 563     BlockDriver *drv = bs->drv;
 564     if (!bs->drv)
 565         return -ENOMEDIUM;
 566     if (bs->read_only)
 567         return -EACCES;
 568     if (drv->bdrv_pwrite) {
 569         int ret, len;
 570         len = nb_sectors * 512;
 571         ret = drv->bdrv_pwrite(bs, sector_num * 512, buf, len);
 572         if (ret < 0)
 573             return ret;
 574         else if (ret != len)
 575             return -EIO;
 576         else {
 577             bs->wr_bytes += (unsigned) len;
 578             bs->wr_ops ++;
 579             return 0;
 580         }
 581     } else {
 582         return drv->bdrv_write(bs, sector_num, buf, nb_sectors);
 583     }
 584 }
 585
 586 static int bdrv_pread_em(BlockDriverState *bs, int64_t offset,
 587                          uint8_t *buf, int count1)
 588 {
 589     uint8_t tmp_buf[SECTOR_SIZE];
 590     int len, nb_sectors, count;
 591     int64_t sector_num;
 592
 593     count = count1;
 594     /* first read to align to sector start */
 595     len = (SECTOR_SIZE - offset) & (SECTOR_SIZE - 1);
 596     if (len > count)
 597         len = count;
 598     sector_num = offset >> SECTOR_BITS;
 599     if (len > 0) {
 600         if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
 601             return -EIO;
 602         memcpy(buf, tmp_buf + (offset & (SECTOR_SIZE - 1)), len);
 603         count -= len;
 604         if (count == 0)
 605             return count1;
 606         sector_num++;
 607         buf += len;
 608     }
 609
 610     /* read the sectors "in place" */
 611     nb_sectors = count >> SECTOR_BITS;
 612     if (nb_sectors > 0) {
 613         if (bdrv_read(bs, sector_num, buf, nb_sectors) < 0)
 614             return -EIO;
 615         sector_num += nb_sectors;
 616         len = nb_sectors << SECTOR_BITS;
 617         buf += len;
 618         count -= len;
 619     }
 620
 621     /* add data from the last sector */
 622     if (count > 0) {
 623         if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
 624             return -EIO;
 625         memcpy(buf, tmp_buf, count);
 626     }
 627     return count1;
 628 }
 629
 630 static int bdrv_pwrite_em(BlockDriverState *bs, int64_t offset,
 631                           const uint8_t *buf, int count1)
 632 {
 633     uint8_t tmp_buf[SECTOR_SIZE];
 634     int len, nb_sectors, count;
 635     int64_t sector_num;
 636
 637     count = count1;
 638     /* first write to align to sector start */
 639     len = (SECTOR_SIZE - offset) & (SECTOR_SIZE - 1);
 640     if (len > count)
 641         len = count;
 642     sector_num = offset >> SECTOR_BITS;
 643     if (len > 0) {
 644         if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
 645             return -EIO;
 646         memcpy(tmp_buf + (offset & (SECTOR_SIZE - 1)), buf, len);
 647         if (bdrv_write(bs, sector_num, tmp_buf, 1) < 0)
 648             return -EIO;
 649         count -= len;
 650         if (count == 0)
 651             return count1;
 652         sector_num++;
 653         buf += len;
 654     }
 655
 656     /* write the sectors "in place" */
 657     nb_sectors = count >> SECTOR_BITS;
 658     if (nb_sectors > 0) {
 659         if (bdrv_write(bs, sector_num, buf, nb_sectors) < 0)
 660             return -EIO;
 661         sector_num += nb_sectors;
 662         len = nb_sectors << SECTOR_BITS;
 663         buf += len;
 664         count -= len;
 665     }
 666
 667     /* add data from the last sector */
 668     if (count > 0) {
 669         if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
 670             return -EIO;
 671         memcpy(tmp_buf, buf, count);
 672         if (bdrv_write(bs, sector_num, tmp_buf, 1) < 0)
 673             return -EIO;
 674     }
 675     return count1;
 676 }
 677
 678 /**
 679  * Read with byte offsets (needed only for file protocols)
 680  */
 681 int bdrv_pread(BlockDriverState *bs, int64_t offset,
 682                void *buf1, int count1)
 683 {
 684     BlockDriver *drv = bs->drv;
 685
 686     if (!drv)
 687         return -ENOMEDIUM;
 688     if (!drv->bdrv_pread)
 689         return bdrv_pread_em(bs, offset, buf1, count1);
 690     return drv->bdrv_pread(bs, offset, buf1, count1);
 691 }
 692
 693 /**
 694  * Write with byte offsets (needed only for file protocols)
 695  */
 696 int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
 697                 const void *buf1, int count1)
 698 {
 699     BlockDriver *drv = bs->drv;
 700
 701     if (!drv)
 702         return -ENOMEDIUM;
 703     if (!drv->bdrv_pwrite)
 704         return bdrv_pwrite_em(bs, offset, buf1, count1);
 705     return drv->bdrv_pwrite(bs, offset, buf1, count1);
 706 }
 707
 708 /**
 709  * Truncate file to 'offset' bytes (needed only for file protocols)
 710  */
 711 int bdrv_truncate(BlockDriverState *bs, int64_t offset)
 712 {
 713     BlockDriver *drv = bs->drv;
 714     if (!drv)
 715         return -ENOMEDIUM;
 716     if (!drv->bdrv_truncate)
 717         return -ENOTSUP;
 718     return drv->bdrv_truncate(bs, offset);
 719 }
 720
 721 /**
 722  * Length of a file in bytes. Return < 0 if error or unknown.
 723  */
 724 int64_t bdrv_getlength(BlockDriverState *bs)
 725 {
 726     BlockDriver *drv = bs->drv;
 727     if (!drv)
 728         return -ENOMEDIUM;
 729     if (!drv->bdrv_getlength) {
 730         /* legacy mode */
 731         return bs->total_sectors * SECTOR_SIZE;
 732     }
 733     return drv->bdrv_getlength(bs);
 734 }
 735
 736 /* return 0 as number of sectors if no device present or error */
 737 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
 738 {
 739     int64_t length;
 740     length = bdrv_getlength(bs);
 741     if (length < 0)
 742         length = 0;
 743     else
 744         length = length >> SECTOR_BITS;
 745     *nb_sectors_ptr = length;
 746 }
 747
 748 struct partition {
 749         uint8_t boot_ind;           /* 0x80 - active */
 750         uint8_t head;               /* starting head */
 751         uint8_t sector;             /* starting sector */
 752         uint8_t cyl;                /* starting cylinder */
 753         uint8_t sys_ind;            /* What partition type */
 754         uint8_t end_head;           /* end head */
 755         uint8_t end_sector;         /* end sector */
 756         uint8_t end_cyl;            /* end cylinder */
 757         uint32_t start_sect;        /* starting sector counting from 0 */
 758         uint32_t nr_sects;          /* nr of sectors in partition */
 759 } __attribute__((packed));
 760
 761 /* try to guess the disk logical geometry from the MSDOS partition table. Return 0 if OK, -1 if could not guess */
 762 static int guess_disk_lchs(BlockDriverState *bs,
 763                            int *pcylinders, int *pheads, int *psectors)
 764 {
 765     uint8_t *buf;
 766     int ret, i, heads, sectors, cylinders;
 767     struct partition *p;
 768     uint32_t nr_sects;
 769     uint64_t nb_sectors;
 770
 771     buf = qemu_memalign(512, 512);
 772     if (buf == NULL)
 773         return -1;
 774
 775     bdrv_get_geometry(bs, &nb_sectors);
 776
 777     ret = bdrv_read(bs, 0, buf, 1);
 778     if (ret < 0)
 779         return -1;
 780     /* test msdos magic */
 781     if (buf[510] != 0x55 || buf[511] != 0xaa) {
 782         qemu_free(buf);
 783         return -1;
 784     }
 785     for(i = 0; i < 4; i++) {
 786         p = ((struct partition *)(buf + 0x1be)) + i;
 787         nr_sects = le32_to_cpu(p->nr_sects);
 788         if (nr_sects && p->end_head) {
 789             /* We make the assumption that the partition terminates on
 790                a cylinder boundary */
 791             heads = p->end_head + 1;
 792             sectors = p->end_sector & 63;
 793             if (sectors == 0)
 794                 continue;
 795             cylinders = nb_sectors / (heads * sectors);
 796             if (cylinders < 1 || cylinders > 16383)
 797                 continue;
 798             *pheads = heads;
 799             *psectors = sectors;
 800             *pcylinders = cylinders;
 801 #if 0
 802             printf("guessed geometry: LCHS=%d %d %d\n",
 803                    cylinders, heads, sectors);
 804 #endif
 805             qemu_free(buf);
 806             return 0;
 807         }
 808     }
 809     qemu_free(buf);
 810     return -1;
 811 }
 812
 813 void bdrv_guess_geometry(BlockDriverState *bs, int *pcyls, int *pheads, int *psecs)
 814 {
 815     int translation, lba_detected = 0;
 816     int cylinders, heads, secs;
 817     uint64_t nb_sectors;
 818
 819     /* if a geometry hint is available, use it */
 820     bdrv_get_geometry(bs, &nb_sectors);
 821     bdrv_get_geometry_hint(bs, &cylinders, &heads, &secs);
 822     translation = bdrv_get_translation_hint(bs);
 823     if (cylinders != 0) {
 824         *pcyls = cylinders;
 825         *pheads = heads;
 826         *psecs = secs;
 827     } else {
 828         if (guess_disk_lchs(bs, &cylinders, &heads, &secs) == 0) {
 829             if (heads > 16) {
 830                 /* if heads > 16, it means that a BIOS LBA
 831                    translation was active, so the default
 832                    hardware geometry is OK */
 833                 lba_detected = 1;
 834                 goto default_geometry;
 835             } else {
 836                 *pcyls = cylinders;
 837                 *pheads = heads;
 838                 *psecs = secs;
 839                 /* disable any translation to be in sync with
 840                    the logical geometry */
 841                 if (translation == BIOS_ATA_TRANSLATION_AUTO) {
 842                     bdrv_set_translation_hint(bs,
 843                                               BIOS_ATA_TRANSLATION_NONE);
 844                 }
 845             }
 846         } else {
 847         default_geometry:
 848             /* if no geometry, use a standard physical disk geometry */
 849             cylinders = nb_sectors / (16 * 63);
 850
 851             if (cylinders > 16383)
 852                 cylinders = 16383;
 853             else if (cylinders < 2)
 854                 cylinders = 2;
 855             *pcyls = cylinders;
 856             *pheads = 16;
 857             *psecs = 63;
 858             if ((lba_detected == 1) && (translation == BIOS_ATA_TRANSLATION_AUTO)) {
 859                 if ((*pcyls * *pheads) <= 131072) {
 860                     bdrv_set_translation_hint(bs,
 861                                               BIOS_ATA_TRANSLATION_LARGE);
 862                 } else {
 863                     bdrv_set_translation_hint(bs,
 864                                               BIOS_ATA_TRANSLATION_LBA);
 865                 }
 866             }
 867         }
 868         bdrv_set_geometry_hint(bs, *pcyls, *pheads, *psecs);
 869     }
 870 }
 871
 872 void bdrv_set_geometry_hint(BlockDriverState *bs,
 873                             int cyls, int heads, int secs)
 874 {
 875     bs->cyls = cyls;
 876     bs->heads = heads;
 877     bs->secs = secs;
 878 }
 879
 880 void bdrv_set_type_hint(BlockDriverState *bs, int type)
 881 {
 882     bs->type = type;
 883     bs->removable = ((type == BDRV_TYPE_CDROM ||
 884                       type == BDRV_TYPE_FLOPPY));
 885 }
 886
 887 void bdrv_set_translation_hint(BlockDriverState *bs, int translation)
 888 {
 889     bs->translation = translation;
 890 }
 891
 892 void bdrv_get_geometry_hint(BlockDriverState *bs,
 893                             int *pcyls, int *pheads, int *psecs)
 894 {
 895     *pcyls = bs->cyls;
 896     *pheads = bs->heads;
 897     *psecs = bs->secs;
 898 }
 899
 900 int bdrv_get_type_hint(BlockDriverState *bs)
 901 {
 902     return bs->type;
 903 }
 904
 905 int bdrv_get_translation_hint(BlockDriverState *bs)
 906 {
 907     return bs->translation;
 908 }
 909
 910 int bdrv_is_removable(BlockDriverState *bs)
 911 {
 912     return bs->removable;
 913 }
 914
 915 int bdrv_is_read_only(BlockDriverState *bs)
 916 {
 917     return bs->read_only;
 918 }
 919
 920 int bdrv_is_sg(BlockDriverState *bs)
 921 {
 922     return bs->sg;
 923 }
 924
 925 /* XXX: no longer used */
 926 void bdrv_set_change_cb(BlockDriverState *bs,
 927                         void (*change_cb)(void *opaque), void *opaque)
 928 {
 929     bs->change_cb = change_cb;
 930     bs->change_opaque = opaque;
 931 }
 932
 933 int bdrv_is_encrypted(BlockDriverState *bs)
 934 {
 935     if (bs->backing_hd && bs->backing_hd->encrypted)
 936         return 1;
 937     return bs->encrypted;
 938 }
 939
 940 int bdrv_set_key(BlockDriverState *bs, const char *key)
 941 {
 942     int ret;
 943     if (bs->backing_hd && bs->backing_hd->encrypted) {
 944         ret = bdrv_set_key(bs->backing_hd, key);
 945         if (ret < 0)
 946             return ret;
 947         if (!bs->encrypted)
 948             return 0;
 949     }
 950     if (!bs->encrypted || !bs->drv || !bs->drv->bdrv_set_key)
 951         return -1;
 952     return bs->drv->bdrv_set_key(bs, key);
 953 }
 954
 955 void bdrv_get_format(BlockDriverState *bs, char *buf, int buf_size)
 956 {
 957     if (!bs->drv) {
 958         buf[0] = '\0';
 959     } else {
 960         pstrcpy(buf, buf_size, bs->drv->format_name);
 961     }
 962 }
 963
 964 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 965                          void *opaque)
 966 {
 967     BlockDriver *drv;
 968
 969     for (drv = first_drv; drv != NULL; drv = drv->next) {
 970         it(opaque, drv->format_name);
 971     }
 972 }
 973
 974 BlockDriverState *bdrv_find(const char *name)
 975 {
 976     BlockDriverState *bs;
 977
 978     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
 979         if (!strcmp(name, bs->device_name))
 980             return bs;
 981     }
 982     return NULL;
 983 }
 984
 985 void bdrv_iterate(void (*it)(void *opaque, const char *name), void *opaque)
 986 {
 987     BlockDriverState *bs;
 988
 989     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
 990         it(opaque, bs->device_name);
 991     }
 992 }
 993
 994 const char *bdrv_get_device_name(BlockDriverState *bs)
 995 {
 996     return bs->device_name;
 997 }
 998
 999 void bdrv_flush(BlockDriverState *bs)
1000 {
1001     if (bs->drv->bdrv_flush)
1002         bs->drv->bdrv_flush(bs);
1003     if (bs->backing_hd)
1004         bdrv_flush(bs->backing_hd);
1005 }
1006
1007 void bdrv_iterate_writeable(void (*it)(BlockDriverState *bs))
1008 {
1009     BlockDriverState *bs;
1010
1011     for (bs = bdrv_first; bs != NULL; bs = bs->next)
1012         if (bs->drv && !bdrv_is_read_only(bs) &&
1013             (!bdrv_is_removable(bs) || bdrv_is_inserted(bs)))
1014             it(bs);
1015 }
1016
1017 void bdrv_flush_all(void)
1018 {
1019     BlockDriverState *bs;
1020
1021     for (bs = bdrv_first; bs != NULL; bs = bs->next)
1022         if (bs->drv && !bdrv_is_read_only(bs) &&
1023             (!bdrv_is_removable(bs) || bdrv_is_inserted(bs)))
1024             bdrv_flush(bs);
1025 }
1026
1027 /*
1028  * Returns true iff the specified sector is present in the disk image. Drivers
1029  * not implementing the functionality are assumed to not support backing files,
1030  * hence all their sectors are reported as allocated.
1031  *
1032  * 'pnum' is set to the number of sectors (including and immediately following
1033  * the specified sector) that are known to be in the same
1034  * allocated/unallocated state.
1035  *
1036  * 'nb_sectors' is the max value 'pnum' should be set to.
1037  */
1038 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
1039         int *pnum)
1040 {
1041     int64_t n;
1042     if (!bs->drv->bdrv_is_allocated) {
1043         if (sector_num >= bs->total_sectors) {
1044             *pnum = 0;
1045             return 0;
1046         }
1047         n = bs->total_sectors - sector_num;
1048         *pnum = (n < nb_sectors) ? (n) : (nb_sectors);
1049         return 1;
1050     }
1051     return bs->drv->bdrv_is_allocated(bs, sector_num, nb_sectors, pnum);
1052 }
1053
1054 void bdrv_info(void)
1055 {
1056     BlockDriverState *bs;
1057
1058     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
1059         term_printf("%s:", bs->device_name);
1060         term_printf(" type=");
1061         switch(bs->type) {
1062         case BDRV_TYPE_HD:
1063             term_printf("hd");
1064             break;
1065         case BDRV_TYPE_CDROM:
1066             term_printf("cdrom");
1067             break;
1068         case BDRV_TYPE_FLOPPY:
1069             term_printf("floppy");
1070             break;
1071         }
1072         term_printf(" removable=%d", bs->removable);
1073         if (bs->removable) {
1074             term_printf(" locked=%d", bs->locked);
1075         }
1076         if (bs->drv) {
1077             term_printf(" file=");
1078             term_print_filename(bs->filename);
1079             if (bs->backing_file[0] != '\0') {
1080                 term_printf(" backing_file=");
1081                 term_print_filename(bs->backing_file);
1082             }
1083             term_printf(" ro=%d", bs->read_only);
1084             term_printf(" drv=%s", bs->drv->format_name);
1085             if (bs->encrypted)
1086                 term_printf(" encrypted");
1087         } else {
1088             term_printf(" [not inserted]");
1089         }
1090         term_printf("\n");
1091     }
1092 }
1093
1094 /* The "info blockstats" command. */
1095 void bdrv_info_stats (void)
1096 {
1097     BlockDriverState *bs;
1098
1099     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
1100         term_printf ("%s:"
1101                      " rd_bytes=%" PRIu64
1102                      " wr_bytes=%" PRIu64
1103                      " rd_operations=%" PRIu64
1104                      " wr_operations=%" PRIu64
1105                      "\n",
1106                      bs->device_name,
1107                      bs->rd_bytes, bs->wr_bytes,
1108                      bs->rd_ops, bs->wr_ops);
1109     }
1110 }
1111
1112 void bdrv_get_backing_filename(BlockDriverState *bs,
1113                                char *filename, int filename_size)
1114 {
1115     if (!bs->backing_hd) {
1116         pstrcpy(filename, filename_size, "");
1117     } else {
1118         pstrcpy(filename, filename_size, bs->backing_file);
1119     }
1120 }
1121
1122 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
1123                           const uint8_t *buf, int nb_sectors)
1124 {
1125     BlockDriver *drv = bs->drv;
1126     if (!drv)
1127         return -ENOMEDIUM;
1128     if (!drv->bdrv_write_compressed)
1129         return -ENOTSUP;
1130     return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
1131 }
1132
1133 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1134 {
1135     BlockDriver *drv = bs->drv;
1136     if (!drv)
1137         return -ENOMEDIUM;
1138     if (!drv->bdrv_get_info)
1139         return -ENOTSUP;
1140     memset(bdi, 0, sizeof(*bdi));
1141     return drv->bdrv_get_info(bs, bdi);
1142 }
1143
1144 /**************************************************************/
1145 /* handling of snapshots */
1146
1147 int bdrv_snapshot_create(BlockDriverState *bs,
1148                          QEMUSnapshotInfo *sn_info)
1149 {
1150     BlockDriver *drv = bs->drv;
1151     if (!drv)
1152         return -ENOMEDIUM;
1153     if (!drv->bdrv_snapshot_create)
1154         return -ENOTSUP;
1155     return drv->bdrv_snapshot_create(bs, sn_info);
1156 }
1157
1158 int bdrv_snapshot_goto(BlockDriverState *bs,
1159                        const char *snapshot_id)
1160 {
1161     BlockDriver *drv = bs->drv;
1162     if (!drv)
1163         return -ENOMEDIUM;
1164     if (!drv->bdrv_snapshot_goto)
1165         return -ENOTSUP;
1166     return drv->bdrv_snapshot_goto(bs, snapshot_id);
1167 }
1168
1169 int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
1170 {
1171     BlockDriver *drv = bs->drv;
1172     if (!drv)
1173         return -ENOMEDIUM;
1174     if (!drv->bdrv_snapshot_delete)
1175         return -ENOTSUP;
1176     return drv->bdrv_snapshot_delete(bs, snapshot_id);
1177 }
1178
1179 int bdrv_snapshot_list(BlockDriverState *bs,
1180                        QEMUSnapshotInfo **psn_info)
1181 {
1182     BlockDriver *drv = bs->drv;
1183     if (!drv)
1184         return -ENOMEDIUM;
1185     if (!drv->bdrv_snapshot_list)
1186         return -ENOTSUP;
1187     return drv->bdrv_snapshot_list(bs, psn_info);
1188 }
1189
1190 #define NB_SUFFIXES 4
1191
1192 char *get_human_readable_size(char *buf, int buf_size, int64_t size)
1193 {
1194     static const char suffixes[NB_SUFFIXES] = "KMGT";
1195     int64_t base;
1196     int i;
1197
1198     if (size <= 999) {
1199         snprintf(buf, buf_size, "%" PRId64, size);
1200     } else {
1201         base = 1024;
1202         for(i = 0; i < NB_SUFFIXES; i++) {
1203             if (size < (10 * base)) {
1204                 snprintf(buf, buf_size, "%0.1f%c",
1205                          (double)size / base,
1206                          suffixes[i]);
1207                 break;
1208             } else if (size < (1000 * base) || i == (NB_SUFFIXES - 1)) {
1209                 snprintf(buf, buf_size, "%" PRId64 "%c",
1210                          ((size + (base >> 1)) / base),
1211                          suffixes[i]);
1212                 break;
1213             }
1214             base = base * 1024;
1215         }
1216     }
1217     return buf;
1218 }
1219
1220 char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn)
1221 {
1222     char buf1[128], date_buf[128], clock_buf[128];
1223 #ifdef _WIN32
1224     struct tm *ptm;
1225 #else
1226     struct tm tm;
1227 #endif
1228     time_t ti;
1229     int64_t secs;
1230
1231     if (!sn) {
1232         snprintf(buf, buf_size,
1233                  "%-10s%-20s%7s%20s%15s",
1234                  "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK");
1235     } else {
1236         ti = sn->date_sec;
1237 #ifdef _WIN32
1238         ptm = localtime(&ti);
1239         strftime(date_buf, sizeof(date_buf),
1240                  "%Y-%m-%d %H:%M:%S", ptm);
1241 #else
1242         localtime_r(&ti, &tm);
1243         strftime(date_buf, sizeof(date_buf),
1244                  "%Y-%m-%d %H:%M:%S", &tm);
1245 #endif
1246         secs = sn->vm_clock_nsec / 1000000000;
1247         snprintf(clock_buf, sizeof(clock_buf),
1248                  "%02d:%02d:%02d.%03d",
1249                  (int)(secs / 3600),
1250                  (int)((secs / 60) % 60),
1251                  (int)(secs % 60),
1252                  (int)((sn->vm_clock_nsec / 1000000) % 1000));
1253         snprintf(buf, buf_size,
1254                  "%-10s%-20s%7s%20s%15s",
1255                  sn->id_str, sn->name,
1256                  get_human_readable_size(buf1, sizeof(buf1), sn->vm_state_size),
1257                  date_buf,
1258                  clock_buf);
1259     }
1260     return buf;
1261 }
1262
1263
1264 /**************************************************************/
1265 /* async I/Os */
1266
1267 BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
1268                                 uint8_t *buf, int nb_sectors,
1269                                 BlockDriverCompletionFunc *cb, void *opaque)
1270 {
1271     BlockDriver *drv = bs->drv;
1272     BlockDriverAIOCB *ret;
1273
1274     if (!drv)
1275         return NULL;
1276
1277     ret = drv->bdrv_aio_read(bs, sector_num, buf, nb_sectors, cb, opaque);
1278
1279     if (ret) {
1280         /* Update stats even though technically transfer has not happened. */
1281         bs->rd_bytes += (unsigned) nb_sectors * SECTOR_SIZE;
1282         bs->rd_ops ++;
1283     }
1284
1285     return ret;
1286 }
1287
1288 BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
1289                                  const uint8_t *buf, int nb_sectors,
1290                                  BlockDriverCompletionFunc *cb, void *opaque)
1291 {
1292     BlockDriver *drv = bs->drv;
1293     BlockDriverAIOCB *ret;
1294
1295     if (!drv)
1296         return NULL;
1297     if (bs->read_only)
1298         return NULL;
1299
1300     ret = drv->bdrv_aio_write(bs, sector_num, buf, nb_sectors, cb, opaque);
1301
1302     if (ret) {
1303         /* Update stats even though technically transfer has not happened. */
1304         bs->wr_bytes += (unsigned) nb_sectors * SECTOR_SIZE;
1305         bs->wr_ops ++;
1306     }
1307
1308     return ret;
1309 }
1310
1311 void bdrv_aio_cancel(BlockDriverAIOCB *acb)
1312 {
1313     BlockDriver *drv = acb->bs->drv;
1314
1315     drv->bdrv_aio_cancel(acb);
1316 }
1317
1318
1319 /**************************************************************/
1320 /* async block device emulation */
1321
1322 static void bdrv_aio_bh_cb(void *opaque)
1323 {
1324     BlockDriverAIOCBSync *acb = opaque;
1325     acb->common.cb(acb->common.opaque, acb->ret);
1326     qemu_aio_release(acb);
1327 }
1328
1329 static BlockDriverAIOCB *bdrv_aio_read_em(BlockDriverState *bs,
1330         int64_t sector_num, uint8_t *buf, int nb_sectors,
1331         BlockDriverCompletionFunc *cb, void *opaque)
1332 {
1333     BlockDriverAIOCBSync *acb;
1334     int ret;
1335
1336     acb = qemu_aio_get(bs, cb, opaque);
1337     if (!acb->bh)
1338         acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
1339     ret = bdrv_read(bs, sector_num, buf, nb_sectors);
1340     acb->ret = ret;
1341     qemu_bh_schedule(acb->bh);
1342     return &acb->common;
1343 }
1344
1345 static BlockDriverAIOCB *bdrv_aio_write_em(BlockDriverState *bs,
1346         int64_t sector_num, const uint8_t *buf, int nb_sectors,
1347         BlockDriverCompletionFunc *cb, void *opaque)
1348 {
1349     BlockDriverAIOCBSync *acb;
1350     int ret;
1351
1352     acb = qemu_aio_get(bs, cb, opaque);
1353     if (!acb->bh)
1354         acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
1355     ret = bdrv_write(bs, sector_num, buf, nb_sectors);
1356     acb->ret = ret;
1357     qemu_bh_schedule(acb->bh);
1358     return &acb->common;
1359 }
1360
1361 static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb)
1362 {
1363     BlockDriverAIOCBSync *acb = (BlockDriverAIOCBSync *)blockacb;
1364     qemu_bh_cancel(acb->bh);
1365     qemu_aio_release(acb);
1366 }
1367
1368 /**************************************************************/
1369 /* sync block device emulation */
1370
1371 static void bdrv_rw_em_cb(void *opaque, int ret)
1372 {
1373     *(int *)opaque = ret;
1374 }
1375
1376 #define NOT_DONE 0x7fffffff
1377
1378 static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
1379                         uint8_t *buf, int nb_sectors)
1380 {
1381     int async_ret;
1382     BlockDriverAIOCB *acb;
1383
1384     async_ret = NOT_DONE;
1385     acb = bdrv_aio_read(bs, sector_num, buf, nb_sectors,
1386                         bdrv_rw_em_cb, &async_ret);
1387     if (acb == NULL)
1388         return -1;
1389
1390     while (async_ret == NOT_DONE) {
1391         qemu_aio_wait();
1392     }
1393
1394     return async_ret;
1395 }
1396
1397 static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
1398                          const uint8_t *buf, int nb_sectors)
1399 {
1400     int async_ret;
1401     BlockDriverAIOCB *acb;
1402
1403     async_ret = NOT_DONE;
1404     acb = bdrv_aio_write(bs, sector_num, buf, nb_sectors,
1405                          bdrv_rw_em_cb, &async_ret);
1406     if (acb == NULL)
1407         return -1;
1408     while (async_ret == NOT_DONE) {
1409         qemu_aio_wait();
1410     }
1411     return async_ret;
1412 }
1413
1414 void bdrv_init(void)
1415 {
1416     bdrv_register(&bdrv_raw);
1417     bdrv_register(&bdrv_host_device);
1418 #ifndef _WIN32
1419     bdrv_register(&bdrv_cow);
1420 #endif
1421     bdrv_register(&bdrv_qcow);
1422     bdrv_register(&bdrv_vmdk);
1423     bdrv_register(&bdrv_cloop);
1424     bdrv_register(&bdrv_dmg);
1425     bdrv_register(&bdrv_bochs);
1426     bdrv_register(&bdrv_vpc);
1427     bdrv_register(&bdrv_vvfat);
1428     bdrv_register(&bdrv_qcow2);
1429     bdrv_register(&bdrv_parallels);
1430     bdrv_register(&bdrv_nbd);
1431 }
1432
1433 void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
1434                    void *opaque)
1435 {
1436     BlockDriver *drv;
1437     BlockDriverAIOCB *acb;
1438
1439     drv = bs->drv;
1440     if (drv->free_aiocb) {
1441         acb = drv->free_aiocb;
1442         drv->free_aiocb = acb->next;
1443     } else {
1444         acb = qemu_mallocz(drv->aiocb_size);
1445         if (!acb)
1446             return NULL;
1447     }
1448     acb->bs = bs;
1449     acb->cb = cb;
1450     acb->opaque = opaque;
1451     return acb;
1452 }
1453
1454 void qemu_aio_release(void *p)
1455 {
1456     BlockDriverAIOCB *acb = p;
1457     BlockDriver *drv = acb->bs->drv;
1458     acb->next = drv->free_aiocb;
1459     drv->free_aiocb = acb;
1460 }
1461
1462 /**************************************************************/
1463 /* removable device support */
1464
1465 /**
1466  * Return TRUE if the media is present
1467  */
1468 int bdrv_is_inserted(BlockDriverState *bs)
1469 {
1470     BlockDriver *drv = bs->drv;
1471     int ret;
1472     if (!drv)
1473         return 0;
1474     if (!drv->bdrv_is_inserted)
1475         return 1;
1476     ret = drv->bdrv_is_inserted(bs);
1477     return ret;
1478 }
1479
1480 /**
1481  * Return TRUE if the media changed since the last call to this
1482  * function. It is currently only used for floppy disks
1483  */
1484 int bdrv_media_changed(BlockDriverState *bs)
1485 {
1486     BlockDriver *drv = bs->drv;
1487     int ret;
1488
1489     if (!drv || !drv->bdrv_media_changed)
1490         ret = -ENOTSUP;
1491     else
1492         ret = drv->bdrv_media_changed(bs);
1493     if (ret == -ENOTSUP)
1494         ret = bs->media_changed;
1495     bs->media_changed = 0;
1496     return ret;
1497 }
1498
1499 /**
1500  * If eject_flag is TRUE, eject the media. Otherwise, close the tray
1501  */
1502 void bdrv_eject(BlockDriverState *bs, int eject_flag)
1503 {
1504     BlockDriver *drv = bs->drv;
1505     int ret;
1506
1507     if (!drv || !drv->bdrv_eject) {
1508         ret = -ENOTSUP;
1509     } else {
1510         ret = drv->bdrv_eject(bs, eject_flag);
1511     }
1512     if (ret == -ENOTSUP) {
1513         if (eject_flag)
1514             bdrv_close(bs);
1515     }
1516 }
1517
1518 int bdrv_is_locked(BlockDriverState *bs)
1519 {
1520     return bs->locked;
1521 }
1522
1523 /**
1524  * Lock or unlock the media (if it is locked, the user won't be able
1525  * to eject it manually).
1526  */
1527 void bdrv_set_locked(BlockDriverState *bs, int locked)
1528 {
1529     BlockDriver *drv = bs->drv;
1530
1531     bs->locked = locked;
1532     if (drv && drv->bdrv_set_locked) {
1533         drv->bdrv_set_locked(bs, locked);
1534     }
1535 }
1536
1537 /* needed for generic scsi interface */
1538
1539 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
1540 {
1541     BlockDriver *drv = bs->drv;
1542
1543     if (drv && drv->bdrv_ioctl)
1544         return drv->bdrv_ioctl(bs, req, buf);
1545     return -ENOTSUP;
1546 }