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 "vl.h"
  25 #include "block_int.h"
  26
  27 static BlockDriverState *bdrv_first;
  28 static BlockDriver *first_drv;
  29
  30 void bdrv_register(BlockDriver *bdrv)
  31 {
  32     bdrv->next = first_drv;
  33     first_drv = bdrv;
  34 }
  35
  36 /* create a new block device (by default it is empty) */
  37 BlockDriverState *bdrv_new(const char *device_name)
  38 {
  39     BlockDriverState **pbs, *bs;
  40
  41     bs = qemu_mallocz(sizeof(BlockDriverState));
  42     if(!bs)
  43         return NULL;
  44     pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
  45     if (device_name[0] != '\0') {
  46         /* insert at the end */
  47         pbs = &bdrv_first;
  48         while (*pbs != NULL)
  49             pbs = &(*pbs)->next;
  50         *pbs = bs;
  51     }
  52     return bs;
  53 }
  54
  55 BlockDriver *bdrv_find_format(const char *format_name)
  56 {
  57     BlockDriver *drv1;
  58     for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
  59         if (!strcmp(drv1->format_name, format_name))
  60             return drv1;
  61     }
  62     return NULL;
  63 }
  64
  65 int bdrv_create(BlockDriver *drv,
  66                 const char *filename, int64_t size_in_sectors,
  67                 const char *backing_file, int flags)
  68 {
  69     if (!drv->bdrv_create)
  70         return -ENOTSUP;
  71     return drv->bdrv_create(filename, size_in_sectors, backing_file, flags);
  72 }
  73
  74 #ifdef _WIN32
  75 static void get_tmp_filename(char *filename, int size)
  76 {
  77     /* XXX: find a better function */
  78     tmpnam(filename);
  79 }
  80 #else
  81 static void get_tmp_filename(char *filename, int size)
  82 {
  83     int fd;
  84     /* XXX: race condition possible */
  85     pstrcpy(filename, size, "/tmp/vl.XXXXXX");
  86     fd = mkstemp(filename);
  87     close(fd);
  88 }
  89 #endif
  90
  91 static BlockDriver *find_image_format(const char *filename)
  92 {
  93     int fd, ret, score, score_max;
  94     BlockDriver *drv1, *drv;
  95     uint8_t buf[1024];
  96
  97     fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
  98     if (fd < 0)
  99         return NULL;
 100     ret = read(fd, buf, sizeof(buf));
 101     if (ret < 0) {
 102         close(fd);
 103         return NULL;
 104     }
 105     close(fd);
 106
 107     drv = NULL;
 108     score_max = 0;
 109     for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
 110         score = drv1->bdrv_probe(buf, ret, filename);
 111         if (score > score_max) {
 112             score_max = score;
 113             drv = drv1;
 114         }
 115     }
 116     return drv;
 117 }
 118
 119 int bdrv_open(BlockDriverState *bs, const char *filename, int snapshot)
 120 {
 121     return bdrv_open2(bs, filename, snapshot, NULL);
 122 }
 123
 124 int bdrv_open2(BlockDriverState *bs, const char *filename, int snapshot,
 125                BlockDriver *drv)
 126 {
 127     int ret;
 128     char tmp_filename[1024];
 129
 130     bs->read_only = 0;
 131     bs->is_temporary = 0;
 132     bs->encrypted = 0;
 133
 134     if (snapshot) {
 135         BlockDriverState *bs1;
 136         int64_t total_size;
 137
 138         /* if snapshot, we create a temporary backing file and open it
 139            instead of opening 'filename' directly */
 140
 141         /* if there is a backing file, use it */
 142         bs1 = bdrv_new("");
 143         if (!bs1) {
 144             return -1;
 145         }
 146         if (bdrv_open(bs1, filename, 0) < 0) {
 147             bdrv_delete(bs1);
 148             return -1;
 149         }
 150         total_size = bs1->total_sectors;
 151         bdrv_delete(bs1);
 152
 153         get_tmp_filename(tmp_filename, sizeof(tmp_filename));
 154         /* XXX: use cow for linux as it is more efficient ? */
 155         if (bdrv_create(&bdrv_qcow, tmp_filename,
 156                         total_size, filename, 0) < 0) {
 157             return -1;
 158         }
 159         filename = tmp_filename;
 160         bs->is_temporary = 1;
 161     }
 162
 163     pstrcpy(bs->filename, sizeof(bs->filename), filename);
 164     if (!drv) {
 165         drv = find_image_format(filename);
 166         if (!drv)
 167             return -1;
 168     }
 169     bs->drv = drv;
 170     bs->opaque = qemu_mallocz(drv->instance_size);
 171     if (bs->opaque == NULL && drv->instance_size > 0)
 172         return -1;
 173
 174     ret = drv->bdrv_open(bs, filename);
 175     if (ret < 0) {
 176         qemu_free(bs->opaque);
 177         return -1;
 178     }
 179 #ifndef _WIN32
 180     if (bs->is_temporary) {
 181         unlink(filename);
 182     }
 183 #endif
 184     if (bs->backing_file[0] != '\0' && drv->bdrv_is_allocated) {
 185         /* if there is a backing file, use it */
 186         bs->backing_hd = bdrv_new("");
 187         if (!bs->backing_hd) {
 188         fail:
 189             bdrv_close(bs);
 190             return -1;
 191         }
 192         if (bdrv_open(bs->backing_hd, bs->backing_file, 0) < 0)
 193             goto fail;
 194     }
 195
 196     bs->inserted = 1;
 197
 198     /* call the change callback */
 199     if (bs->change_cb)
 200         bs->change_cb(bs->change_opaque);
 201
 202     return 0;
 203 }
 204
 205 void bdrv_close(BlockDriverState *bs)
 206 {
 207     if (bs->inserted) {
 208         if (bs->backing_hd)
 209             bdrv_delete(bs->backing_hd);
 210         bs->drv->bdrv_close(bs);
 211         qemu_free(bs->opaque);
 212 #ifdef _WIN32
 213         if (bs->is_temporary) {
 214             unlink(bs->filename);
 215         }
 216 #endif
 217         bs->opaque = NULL;
 218         bs->drv = NULL;
 219         bs->inserted = 0;
 220
 221         /* call the change callback */
 222         if (bs->change_cb)
 223             bs->change_cb(bs->change_opaque);
 224     }
 225 }
 226
 227 void bdrv_delete(BlockDriverState *bs)
 228 {
 229     /* XXX: remove the driver list */
 230     bdrv_close(bs);
 231     qemu_free(bs);
 232 }
 233
 234 /* commit COW file into the raw image */
 235 int bdrv_commit(BlockDriverState *bs)
 236 {
 237     int64_t i;
 238     int n, j;
 239     unsigned char sector[512];
 240
 241     if (!bs->inserted)
 242         return -ENOENT;
 243
 244     if (bs->read_only) {
 245         return -EACCES;
 246     }
 247
 248     if (!bs->backing_hd) {
 249         return -ENOTSUP;
 250     }
 251
 252     for (i = 0; i < bs->total_sectors;) {
 253         if (bs->drv->bdrv_is_allocated(bs, i, 65536, &n)) {
 254             for(j = 0; j < n; j++) {
 255                 if (bdrv_read(bs, i, sector, 1) != 0) {
 256                     return -EIO;
 257                 }
 258
 259                 if (bdrv_write(bs->backing_hd, i, sector, 1) != 0) {
 260                     return -EIO;
 261                 }
 262                 i++;
 263             }
 264         } else {
 265             i += n;
 266         }
 267     }
 268     return 0;
 269 }
 270
 271 /* return -1 if error */
 272 int bdrv_read(BlockDriverState *bs, int64_t sector_num,
 273               uint8_t *buf, int nb_sectors)
 274 {
 275     int ret, n;
 276     BlockDriver *drv = bs->drv;
 277
 278     if (!bs->inserted)
 279         return -1;
 280
 281     while (nb_sectors > 0) {
 282         if (sector_num == 0 && bs->boot_sector_enabled) {
 283             memcpy(buf, bs->boot_sector_data, 512);
 284             n = 1;
 285         } else if (bs->backing_hd) {
 286             if (drv->bdrv_is_allocated(bs, sector_num, nb_sectors, &n)) {
 287                 ret = drv->bdrv_read(bs, sector_num, buf, n);
 288                 if (ret < 0)
 289                     return -1;
 290             } else {
 291                 /* read from the base image */
 292                 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
 293                 if (ret < 0)
 294                     return -1;
 295             }
 296         } else {
 297             ret = drv->bdrv_read(bs, sector_num, buf, nb_sectors);
 298             if (ret < 0)
 299                 return -1;
 300             /* no need to loop */
 301             break;
 302         }
 303         nb_sectors -= n;
 304         sector_num += n;
 305         buf += n * 512;
 306     }
 307     return 0;
 308 }
 309
 310 /* return -1 if error */
 311 int bdrv_write(BlockDriverState *bs, int64_t sector_num,
 312                const uint8_t *buf, int nb_sectors)
 313 {
 314     if (!bs->inserted)
 315         return -1;
 316     if (bs->read_only)
 317         return -1;
 318     return bs->drv->bdrv_write(bs, sector_num, buf, nb_sectors);
 319 }
 320
 321 void bdrv_get_geometry(BlockDriverState *bs, int64_t *nb_sectors_ptr)
 322 {
 323     *nb_sectors_ptr = bs->total_sectors;
 324 }
 325
 326 /* force a given boot sector. */
 327 void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size)
 328 {
 329     bs->boot_sector_enabled = 1;
 330     if (size > 512)
 331         size = 512;
 332     memcpy(bs->boot_sector_data, data, size);
 333     memset(bs->boot_sector_data + size, 0, 512 - size);
 334 }
 335
 336 void bdrv_set_geometry_hint(BlockDriverState *bs,
 337                             int cyls, int heads, int secs)
 338 {
 339     bs->cyls = cyls;
 340     bs->heads = heads;
 341     bs->secs = secs;
 342 }
 343
 344 void bdrv_set_type_hint(BlockDriverState *bs, int type)
 345 {
 346     bs->type = type;
 347     bs->removable = ((type == BDRV_TYPE_CDROM ||
 348                       type == BDRV_TYPE_FLOPPY));
 349 }
 350
 351 void bdrv_set_translation_hint(BlockDriverState *bs, int translation)
 352 {
 353     bs->translation = translation;
 354 }
 355
 356 void bdrv_get_geometry_hint(BlockDriverState *bs,
 357                             int *pcyls, int *pheads, int *psecs)
 358 {
 359     *pcyls = bs->cyls;
 360     *pheads = bs->heads;
 361     *psecs = bs->secs;
 362 }
 363
 364 int bdrv_get_type_hint(BlockDriverState *bs)
 365 {
 366     return bs->type;
 367 }
 368
 369 int bdrv_get_translation_hint(BlockDriverState *bs)
 370 {
 371     return bs->translation;
 372 }
 373
 374 int bdrv_is_removable(BlockDriverState *bs)
 375 {
 376     return bs->removable;
 377 }
 378
 379 int bdrv_is_read_only(BlockDriverState *bs)
 380 {
 381     return bs->read_only;
 382 }
 383
 384 int bdrv_is_inserted(BlockDriverState *bs)
 385 {
 386     return bs->inserted;
 387 }
 388
 389 int bdrv_is_locked(BlockDriverState *bs)
 390 {
 391     return bs->locked;
 392 }
 393
 394 void bdrv_set_locked(BlockDriverState *bs, int locked)
 395 {
 396     bs->locked = locked;
 397 }
 398
 399 void bdrv_set_change_cb(BlockDriverState *bs,
 400                         void (*change_cb)(void *opaque), void *opaque)
 401 {
 402     bs->change_cb = change_cb;
 403     bs->change_opaque = opaque;
 404 }
 405
 406 int bdrv_is_encrypted(BlockDriverState *bs)
 407 {
 408     if (bs->backing_hd && bs->backing_hd->encrypted)
 409         return 1;
 410     return bs->encrypted;
 411 }
 412
 413 int bdrv_set_key(BlockDriverState *bs, const char *key)
 414 {
 415     int ret;
 416     if (bs->backing_hd && bs->backing_hd->encrypted) {
 417         ret = bdrv_set_key(bs->backing_hd, key);
 418         if (ret < 0)
 419             return ret;
 420         if (!bs->encrypted)
 421             return 0;
 422     }
 423     if (!bs->encrypted || !bs->drv || !bs->drv->bdrv_set_key)
 424         return -1;
 425     return bs->drv->bdrv_set_key(bs, key);
 426 }
 427
 428 void bdrv_get_format(BlockDriverState *bs, char *buf, int buf_size)
 429 {
 430     if (!bs->inserted || !bs->drv) {
 431         buf[0] = '\0';
 432     } else {
 433         pstrcpy(buf, buf_size, bs->drv->format_name);
 434     }
 435 }
 436
 437 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 438                          void *opaque)
 439 {
 440     BlockDriver *drv;
 441
 442     for (drv = first_drv; drv != NULL; drv = drv->next) {
 443         it(opaque, drv->format_name);
 444     }
 445 }
 446
 447 BlockDriverState *bdrv_find(const char *name)
 448 {
 449     BlockDriverState *bs;
 450
 451     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
 452         if (!strcmp(name, bs->device_name))
 453             return bs;
 454     }
 455     return NULL;
 456 }
 457
 458 void bdrv_iterate(void (*it)(void *opaque, const char *name), void *opaque)
 459 {
 460     BlockDriverState *bs;
 461
 462     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
 463         it(opaque, bs->device_name);
 464     }
 465 }
 466
 467 const char *bdrv_get_device_name(BlockDriverState *bs)
 468 {
 469     return bs->device_name;
 470 }
 471
 472 void bdrv_info(void)
 473 {
 474     BlockDriverState *bs;
 475
 476     for (bs = bdrv_first; bs != NULL; bs = bs->next) {
 477         term_printf("%s:", bs->device_name);
 478         term_printf(" type=");
 479         switch(bs->type) {
 480         case BDRV_TYPE_HD:
 481             term_printf("hd");
 482             break;
 483         case BDRV_TYPE_CDROM:
 484             term_printf("cdrom");
 485             break;
 486         case BDRV_TYPE_FLOPPY:
 487             term_printf("floppy");
 488             break;
 489         }
 490         term_printf(" removable=%d", bs->removable);
 491         if (bs->removable) {
 492             term_printf(" locked=%d", bs->locked);
 493         }
 494         if (bs->inserted) {
 495             term_printf(" file=%s", bs->filename);
 496             if (bs->backing_file[0] != '\0')
 497                 term_printf(" backing_file=%s", bs->backing_file);
 498             term_printf(" ro=%d", bs->read_only);
 499             term_printf(" drv=%s", bs->drv->format_name);
 500             if (bs->encrypted)
 501                 term_printf(" encrypted");
 502         } else {
 503             term_printf(" [not inserted]");
 504         }
 505         term_printf("\n");
 506     }
 507 }
 508
 509
 510 /**************************************************************/
 511 /* RAW block driver */
 512
 513 typedef struct BDRVRawState {
 514     int fd;
 515 } BDRVRawState;
 516
 517 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 518 {
 519     return 1; /* maybe */
 520 }
 521
 522 static int raw_open(BlockDriverState *bs, const char *filename)
 523 {
 524     BDRVRawState *s = bs->opaque;
 525     int fd;
 526     int64_t size;
 527
 528     fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
 529     if (fd < 0) {
 530         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
 531         if (fd < 0)
 532             return -1;
 533         bs->read_only = 1;
 534     }
 535     size = lseek(fd, 0, SEEK_END);
 536     bs->total_sectors = size / 512;
 537     s->fd = fd;
 538     return 0;
 539 }
 540
 541 static int raw_read(BlockDriverState *bs, int64_t sector_num,
 542                     uint8_t *buf, int nb_sectors)
 543 {
 544     BDRVRawState *s = bs->opaque;
 545     int ret;
 546
 547     lseek(s->fd, sector_num * 512, SEEK_SET);
 548     ret = read(s->fd, buf, nb_sectors * 512);
 549     if (ret != nb_sectors * 512)
 550         return -1;
 551     return 0;
 552 }
 553
 554 static int raw_write(BlockDriverState *bs, int64_t sector_num,
 555                      const uint8_t *buf, int nb_sectors)
 556 {
 557     BDRVRawState *s = bs->opaque;
 558     int ret;
 559
 560     lseek(s->fd, sector_num * 512, SEEK_SET);
 561     ret = write(s->fd, buf, nb_sectors * 512);
 562     if (ret != nb_sectors * 512)
 563         return -1;
 564     return 0;
 565 }
 566
 567 static void raw_close(BlockDriverState *bs)
 568 {
 569     BDRVRawState *s = bs->opaque;
 570     close(s->fd);
 571 }
 572
 573 static int raw_create(const char *filename, int64_t total_size,
 574                       const char *backing_file, int flags)
 575 {
 576     int fd;
 577
 578     if (flags || backing_file)
 579         return -ENOTSUP;
 580
 581     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
 582               0644);
 583     if (fd < 0)
 584         return -EIO;
 585     ftruncate(fd, total_size * 512);
 586     close(fd);
 587     return 0;
 588 }
 589
 590 BlockDriver bdrv_raw = {
 591     "raw",
 592     sizeof(BDRVRawState),
 593     raw_probe,
 594     raw_open,
 595     raw_read,
 596     raw_write,
 597     raw_close,
 598     raw_create,
 599 };
 600
 601 void bdrv_init(void)
 602 {
 603     bdrv_register(&bdrv_raw);
 604 #ifndef _WIN32
 605     bdrv_register(&bdrv_cow);
 606 #endif
 607     bdrv_register(&bdrv_qcow);
 608     bdrv_register(&bdrv_vmdk);
 609     bdrv_register(&bdrv_cloop);
 610     bdrv_register(&bdrv_dmg);
 611 }