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