block/curl.c

   1 /*
   2  * QEMU Block driver for CURL images
   3  *
   4  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu-common.h"
  25 #include "block/block_int.h"
  26 #include <curl/curl.h>
  27
  28 // #define DEBUG
  29 // #define DEBUG_VERBOSE
  30
  31 #ifdef DEBUG_CURL
  32 #define DPRINTF(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)
  33 #else
  34 #define DPRINTF(fmt, ...) do { } while (0)
  35 #endif
  36
  37 #define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \
  38                    CURLPROTO_FTP | CURLPROTO_FTPS | \
  39                    CURLPROTO_TFTP)
  40
  41 #define CURL_NUM_STATES 8
  42 #define CURL_NUM_ACB    8
  43 #define SECTOR_SIZE     512
  44 #define READ_AHEAD_SIZE (256 * 1024)
  45
  46 #define FIND_RET_NONE   0
  47 #define FIND_RET_OK     1
  48 #define FIND_RET_WAIT   2
  49
  50 struct BDRVCURLState;
  51
  52 typedef struct CURLAIOCB {
  53     BlockDriverAIOCB common;
  54     QEMUBH *bh;
  55     QEMUIOVector *qiov;
  56
  57     int64_t sector_num;
  58     int nb_sectors;
  59
  60     size_t start;
  61     size_t end;
  62 } CURLAIOCB;
  63
  64 typedef struct CURLState
  65 {
  66     struct BDRVCURLState *s;
  67     CURLAIOCB *acb[CURL_NUM_ACB];
  68     CURL *curl;
  69     char *orig_buf;
  70     size_t buf_start;
  71     size_t buf_off;
  72     size_t buf_len;
  73     char range[128];
  74     char errmsg[CURL_ERROR_SIZE];
  75     char in_use;
  76 } CURLState;
  77
  78 typedef struct BDRVCURLState {
  79     CURLM *multi;
  80     size_t len;
  81     CURLState states[CURL_NUM_STATES];
  82     char *url;
  83     size_t readahead_size;
  84     bool accept_range;
  85 } BDRVCURLState;
  86
  87 static void curl_clean_state(CURLState *s);
  88 static void curl_multi_do(void *arg);
  89 static int curl_aio_flush(void *opaque);
  90
  91 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
  92                         void *s, void *sp)
  93 {
  94     DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
  95     switch (action) {
  96         case CURL_POLL_IN:
  97             qemu_aio_set_fd_handler(fd, curl_multi_do, NULL, curl_aio_flush, s);
  98             break;
  99         case CURL_POLL_OUT:
 100             qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, curl_aio_flush, s);
 101             break;
 102         case CURL_POLL_INOUT:
 103             qemu_aio_set_fd_handler(fd, curl_multi_do, curl_multi_do,
 104                                     curl_aio_flush, s);
 105             break;
 106         case CURL_POLL_REMOVE:
 107             qemu_aio_set_fd_handler(fd, NULL, NULL, NULL, NULL);
 108             break;
 109     }
 110
 111     return 0;
 112 }
 113
 114 static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 115 {
 116     BDRVCURLState *s = opaque;
 117     size_t realsize = size * nmemb;
 118     const char *accept_line = "Accept-Ranges: bytes";
 119
 120     if (realsize >= strlen(accept_line)
 121         && strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
 122         s->accept_range = true;
 123     }
 124
 125     return realsize;
 126 }
 127
 128 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 129 {
 130     CURLState *s = ((CURLState*)opaque);
 131     size_t realsize = size * nmemb;
 132     int i;
 133
 134     DPRINTF("CURL: Just reading %zd bytes\n", realsize);
 135
 136     if (!s || !s->orig_buf)
 137         goto read_end;
 138
 139     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 140     s->buf_off += realsize;
 141
 142     for(i=0; i<CURL_NUM_ACB; i++) {
 143         CURLAIOCB *acb = s->acb[i];
 144
 145         if (!acb)
 146             continue;
 147
 148         if ((s->buf_off >= acb->end)) {
 149             qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start,
 150                                 acb->end - acb->start);
 151             acb->common.cb(acb->common.opaque, 0);
 152             qemu_aio_release(acb);
 153             s->acb[i] = NULL;
 154         }
 155     }
 156
 157 read_end:
 158     return realsize;
 159 }
 160
 161 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
 162                          CURLAIOCB *acb)
 163 {
 164     int i;
 165     size_t end = start + len;
 166
 167     for (i=0; i<CURL_NUM_STATES; i++) {
 168         CURLState *state = &s->states[i];
 169         size_t buf_end = (state->buf_start + state->buf_off);
 170         size_t buf_fend = (state->buf_start + state->buf_len);
 171
 172         if (!state->orig_buf)
 173             continue;
 174         if (!state->buf_off)
 175             continue;
 176
 177         // Does the existing buffer cover our section?
 178         if ((start >= state->buf_start) &&
 179             (start <= buf_end) &&
 180             (end >= state->buf_start) &&
 181             (end <= buf_end))
 182         {
 183             char *buf = state->orig_buf + (start - state->buf_start);
 184
 185             qemu_iovec_from_buf(acb->qiov, 0, buf, len);
 186             acb->common.cb(acb->common.opaque, 0);
 187
 188             return FIND_RET_OK;
 189         }
 190
 191         // Wait for unfinished chunks
 192         if ((start >= state->buf_start) &&
 193             (start <= buf_fend) &&
 194             (end >= state->buf_start) &&
 195             (end <= buf_fend))
 196         {
 197             int j;
 198
 199             acb->start = start - state->buf_start;
 200             acb->end = acb->start + len;
 201
 202             for (j=0; j<CURL_NUM_ACB; j++) {
 203                 if (!state->acb[j]) {
 204                     state->acb[j] = acb;
 205                     return FIND_RET_WAIT;
 206                 }
 207             }
 208         }
 209     }
 210
 211     return FIND_RET_NONE;
 212 }
 213
 214 static void curl_multi_do(void *arg)
 215 {
 216     BDRVCURLState *s = (BDRVCURLState *)arg;
 217     int running;
 218     int r;
 219     int msgs_in_queue;
 220
 221     if (!s->multi)
 222         return;
 223
 224     do {
 225         r = curl_multi_socket_all(s->multi, &running);
 226     } while(r == CURLM_CALL_MULTI_PERFORM);
 227
 228     /* Try to find done transfers, so we can free the easy
 229      * handle again. */
 230     do {
 231         CURLMsg *msg;
 232         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 233
 234         if (!msg)
 235             break;
 236         if (msg->msg == CURLMSG_NONE)
 237             break;
 238
 239         switch (msg->msg) {
 240             case CURLMSG_DONE:
 241             {
 242                 CURLState *state = NULL;
 243                 curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, (char**)&state);
 244
 245                 /* ACBs for successful messages get completed in curl_read_cb */
 246                 if (msg->data.result != CURLE_OK) {
 247                     int i;
 248                     for (i = 0; i < CURL_NUM_ACB; i++) {
 249                         CURLAIOCB *acb = state->acb[i];
 250
 251                         if (acb == NULL) {
 252                             continue;
 253                         }
 254
 255                         acb->common.cb(acb->common.opaque, -EIO);
 256                         qemu_aio_release(acb);
 257                         state->acb[i] = NULL;
 258                     }
 259                 }
 260
 261                 curl_clean_state(state);
 262                 break;
 263             }
 264             default:
 265                 msgs_in_queue = 0;
 266                 break;
 267         }
 268     } while(msgs_in_queue);
 269 }
 270
 271 static CURLState *curl_init_state(BDRVCURLState *s)
 272 {
 273     CURLState *state = NULL;
 274     int i, j;
 275
 276     do {
 277         for (i=0; i<CURL_NUM_STATES; i++) {
 278             for (j=0; j<CURL_NUM_ACB; j++)
 279                 if (s->states[i].acb[j])
 280                     continue;
 281             if (s->states[i].in_use)
 282                 continue;
 283
 284             state = &s->states[i];
 285             state->in_use = 1;
 286             break;
 287         }
 288         if (!state) {
 289             g_usleep(100);
 290             curl_multi_do(s);
 291         }
 292     } while(!state);
 293
 294     if (state->curl)
 295         goto has_curl;
 296
 297     state->curl = curl_easy_init();
 298     if (!state->curl)
 299         return NULL;
 300     curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 301     curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);
 302     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);
 303     curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 304     curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 305     curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 306     curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 307     curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 308     curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 309     curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
 310
 311     /* Restrict supported protocols to avoid security issues in the more
 312      * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see
 313      * CVE-2013-0249.
 314      *
 315      * Restricting protocols is only supported from 7.19.4 upwards.
 316      */
 317 #if LIBCURL_VERSION_NUM >= 0x071304
 318     curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);
 319     curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);
 320 #endif
 321
 322 #ifdef DEBUG_VERBOSE
 323     curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 324 #endif
 325
 326 has_curl:
 327
 328     state->s = s;
 329
 330     return state;
 331 }
 332
 333 static void curl_clean_state(CURLState *s)
 334 {
 335     if (s->s->multi)
 336         curl_multi_remove_handle(s->s->multi, s->curl);
 337     s->in_use = 0;
 338 }
 339
 340 static void curl_parse_filename(const char *filename, QDict *options,
 341                                 Error **errp)
 342 {
 343
 344     #define RA_OPTSTR ":readahead="
 345     char *file;
 346     char *ra;
 347     const char *ra_val;
 348     int parse_state = 0;
 349
 350     file = g_strdup(filename);
 351
 352     /* Parse a trailing ":readahead=#:" param, if present. */
 353     ra = file + strlen(file) - 1;
 354     while (ra >= file) {
 355         if (parse_state == 0) {
 356             if (*ra == ':') {
 357                 parse_state++;
 358             } else {
 359                 break;
 360             }
 361         } else if (parse_state == 1) {
 362             if (*ra > '9' || *ra < '0') {
 363                 char *opt_start = ra - strlen(RA_OPTSTR) + 1;
 364                 if (opt_start > file &&
 365                     strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {
 366                     ra_val = ra + 1;
 367                     ra -= strlen(RA_OPTSTR) - 1;
 368                     *ra = '\0';
 369                     qdict_put(options, "readahead", qstring_from_str(ra_val));
 370                 }
 371                 break;
 372             }
 373         }
 374         ra--;
 375     }
 376
 377     qdict_put(options, "url", qstring_from_str(file));
 378
 379     g_free(file);
 380 }
 381
 382 static QemuOptsList runtime_opts = {
 383     .name = "curl",
 384     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 385     .desc = {
 386         {
 387             .name = "url",
 388             .type = QEMU_OPT_STRING,
 389             .help = "URL to open",
 390         },
 391         {
 392             .name = "readahead",
 393             .type = QEMU_OPT_SIZE,
 394             .help = "Readahead size",
 395         },
 396         { /* end of list */ }
 397     },
 398 };
 399
 400 static int curl_open(BlockDriverState *bs, QDict *options, int flags)
 401 {
 402     BDRVCURLState *s = bs->opaque;
 403     CURLState *state = NULL;
 404     QemuOpts *opts;
 405     Error *local_err = NULL;
 406     const char *file;
 407     double d;
 408
 409     static int inited = 0;
 410
 411     if (flags & BDRV_O_RDWR) {
 412         qerror_report(ERROR_CLASS_GENERIC_ERROR,
 413                       "curl block device does not support writes");
 414         return -EROFS;
 415     }
 416
 417     opts = qemu_opts_create_nofail(&runtime_opts);
 418     qemu_opts_absorb_qdict(opts, options, &local_err);
 419     if (error_is_set(&local_err)) {
 420         qerror_report_err(local_err);
 421         error_free(local_err);
 422         goto out_noclean;
 423     }
 424
 425     s->readahead_size = qemu_opt_get_size(opts, "readahead", READ_AHEAD_SIZE);
 426     if ((s->readahead_size & 0x1ff) != 0) {
 427         fprintf(stderr, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512\n",
 428                 s->readahead_size);
 429         goto out_noclean;
 430     }
 431
 432     file = qemu_opt_get(opts, "url");
 433     if (file == NULL) {
 434         qerror_report(ERROR_CLASS_GENERIC_ERROR, "curl block driver requires "
 435                       "an 'url' option");
 436         goto out_noclean;
 437     }
 438
 439     if (!inited) {
 440         curl_global_init(CURL_GLOBAL_ALL);
 441         inited = 1;
 442     }
 443
 444     DPRINTF("CURL: Opening %s\n", file);
 445     s->url = g_strdup(file);
 446     state = curl_init_state(s);
 447     if (!state)
 448         goto out_noclean;
 449
 450     // Get file size
 451
 452     s->accept_range = false;
 453     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 454     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
 455                      curl_header_cb);
 456     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
 457     if (curl_easy_perform(state->curl))
 458         goto out;
 459     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 460     if (d)
 461         s->len = (size_t)d;
 462     else if(!s->len)
 463         goto out;
 464     if ((!strncasecmp(s->url, "http://", strlen("http://"))
 465         || !strncasecmp(s->url, "https://", strlen("https://")))
 466         && !s->accept_range) {
 467         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
 468                 "Server does not support 'range' (byte ranges).");
 469         goto out;
 470     }
 471     DPRINTF("CURL: Size = %zd\n", s->len);
 472
 473     curl_clean_state(state);
 474     curl_easy_cleanup(state->curl);
 475     state->curl = NULL;
 476
 477     // Now we know the file exists and its size, so let's
 478     // initialize the multi interface!
 479
 480     s->multi = curl_multi_init();
 481     curl_multi_setopt(s->multi, CURLMOPT_SOCKETDATA, s);
 482     curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
 483     curl_multi_do(s);
 484
 485     qemu_opts_del(opts);
 486     return 0;
 487
 488 out:
 489     fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);
 490     curl_easy_cleanup(state->curl);
 491     state->curl = NULL;
 492 out_noclean:
 493     g_free(s->url);
 494     qemu_opts_del(opts);
 495     return -EINVAL;
 496 }
 497
 498 static int curl_aio_flush(void *opaque)
 499 {
 500     BDRVCURLState *s = opaque;
 501     int i, j;
 502
 503     for (i=0; i < CURL_NUM_STATES; i++) {
 504         for(j=0; j < CURL_NUM_ACB; j++) {
 505             if (s->states[i].acb[j]) {
 506                 return 1;
 507             }
 508         }
 509     }
 510     return 0;
 511 }
 512
 513 static void curl_aio_cancel(BlockDriverAIOCB *blockacb)
 514 {
 515     // Do we have to implement canceling? Seems to work without...
 516 }
 517
 518 static const AIOCBInfo curl_aiocb_info = {
 519     .aiocb_size         = sizeof(CURLAIOCB),
 520     .cancel             = curl_aio_cancel,
 521 };
 522
 523
 524 static void curl_readv_bh_cb(void *p)
 525 {
 526     CURLState *state;
 527
 528     CURLAIOCB *acb = p;
 529     BDRVCURLState *s = acb->common.bs->opaque;
 530
 531     qemu_bh_delete(acb->bh);
 532     acb->bh = NULL;
 533
 534     size_t start = acb->sector_num * SECTOR_SIZE;
 535     size_t end;
 536
 537     // In case we have the requested data already (e.g. read-ahead),
 538     // we can just call the callback and be done.
 539     switch (curl_find_buf(s, start, acb->nb_sectors * SECTOR_SIZE, acb)) {
 540         case FIND_RET_OK:
 541             qemu_aio_release(acb);
 542             // fall through
 543         case FIND_RET_WAIT:
 544             return;
 545         default:
 546             break;
 547     }
 548
 549     // No cache found, so let's start a new request
 550     state = curl_init_state(s);
 551     if (!state) {
 552         acb->common.cb(acb->common.opaque, -EIO);
 553         qemu_aio_release(acb);
 554         return;
 555     }
 556
 557     acb->start = 0;
 558     acb->end = (acb->nb_sectors * SECTOR_SIZE);
 559
 560     state->buf_off = 0;
 561     if (state->orig_buf)
 562         g_free(state->orig_buf);
 563     state->buf_start = start;
 564     state->buf_len = acb->end + s->readahead_size;
 565     end = MIN(start + state->buf_len, s->len) - 1;
 566     state->orig_buf = g_malloc(state->buf_len);
 567     state->acb[0] = acb;
 568
 569     snprintf(state->range, 127, "%zd-%zd", start, end);
 570     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
 571             (acb->nb_sectors * SECTOR_SIZE), start, state->range);
 572     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 573
 574     curl_multi_add_handle(s->multi, state->curl);
 575     curl_multi_do(s);
 576
 577 }
 578
 579 static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
 580         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 581         BlockDriverCompletionFunc *cb, void *opaque)
 582 {
 583     CURLAIOCB *acb;
 584
 585     acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);
 586
 587     acb->qiov = qiov;
 588     acb->sector_num = sector_num;
 589     acb->nb_sectors = nb_sectors;
 590
 591     acb->bh = qemu_bh_new(curl_readv_bh_cb, acb);
 592
 593     if (!acb->bh) {
 594         DPRINTF("CURL: qemu_bh_new failed\n");
 595         return NULL;
 596     }
 597
 598     qemu_bh_schedule(acb->bh);
 599     return &acb->common;
 600 }
 601
 602 static void curl_close(BlockDriverState *bs)
 603 {
 604     BDRVCURLState *s = bs->opaque;
 605     int i;
 606
 607     DPRINTF("CURL: Close\n");
 608     for (i=0; i<CURL_NUM_STATES; i++) {
 609         if (s->states[i].in_use)
 610             curl_clean_state(&s->states[i]);
 611         if (s->states[i].curl) {
 612             curl_easy_cleanup(s->states[i].curl);
 613             s->states[i].curl = NULL;
 614         }
 615         if (s->states[i].orig_buf) {
 616             g_free(s->states[i].orig_buf);
 617             s->states[i].orig_buf = NULL;
 618         }
 619     }
 620     if (s->multi)
 621         curl_multi_cleanup(s->multi);
 622     g_free(s->url);
 623 }
 624
 625 static int64_t curl_getlength(BlockDriverState *bs)
 626 {
 627     BDRVCURLState *s = bs->opaque;
 628     return s->len;
 629 }
 630
 631 static BlockDriver bdrv_http = {
 632     .format_name            = "http",
 633     .protocol_name          = "http",
 634
 635     .instance_size          = sizeof(BDRVCURLState),
 636     .bdrv_parse_filename    = curl_parse_filename,
 637     .bdrv_file_open         = curl_open,
 638     .bdrv_close             = curl_close,
 639     .bdrv_getlength         = curl_getlength,
 640
 641     .bdrv_aio_readv         = curl_aio_readv,
 642 };
 643
 644 static BlockDriver bdrv_https = {
 645     .format_name            = "https",
 646     .protocol_name          = "https",
 647
 648     .instance_size          = sizeof(BDRVCURLState),
 649     .bdrv_parse_filename    = curl_parse_filename,
 650     .bdrv_file_open         = curl_open,
 651     .bdrv_close             = curl_close,
 652     .bdrv_getlength         = curl_getlength,
 653
 654     .bdrv_aio_readv         = curl_aio_readv,
 655 };
 656
 657 static BlockDriver bdrv_ftp = {
 658     .format_name            = "ftp",
 659     .protocol_name          = "ftp",
 660
 661     .instance_size          = sizeof(BDRVCURLState),
 662     .bdrv_parse_filename    = curl_parse_filename,
 663     .bdrv_file_open         = curl_open,
 664     .bdrv_close             = curl_close,
 665     .bdrv_getlength         = curl_getlength,
 666
 667     .bdrv_aio_readv         = curl_aio_readv,
 668 };
 669
 670 static BlockDriver bdrv_ftps = {
 671     .format_name            = "ftps",
 672     .protocol_name          = "ftps",
 673
 674     .instance_size          = sizeof(BDRVCURLState),
 675     .bdrv_parse_filename    = curl_parse_filename,
 676     .bdrv_file_open         = curl_open,
 677     .bdrv_close             = curl_close,
 678     .bdrv_getlength         = curl_getlength,
 679
 680     .bdrv_aio_readv         = curl_aio_readv,
 681 };
 682
 683 static BlockDriver bdrv_tftp = {
 684     .format_name            = "tftp",
 685     .protocol_name          = "tftp",
 686
 687     .instance_size          = sizeof(BDRVCURLState),
 688     .bdrv_parse_filename    = curl_parse_filename,
 689     .bdrv_file_open         = curl_open,
 690     .bdrv_close             = curl_close,
 691     .bdrv_getlength         = curl_getlength,
 692
 693     .bdrv_aio_readv         = curl_aio_readv,
 694 };
 695
 696 static void curl_block_init(void)
 697 {
 698     bdrv_register(&bdrv_http);
 699     bdrv_register(&bdrv_https);
 700     bdrv_register(&bdrv_ftp);
 701     bdrv_register(&bdrv_ftps);
 702     bdrv_register(&bdrv_tftp);
 703 }
 704
 705 block_init(curl_block_init);