qemu/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 "qemu/error-report.h"
  26 #include "block/block_int.h"
  27 #include "qapi/qmp/qbool.h"
  28 #include "qapi/qmp/qstring.h"
  29 #include <curl/curl.h>
  30
  31 // #define DEBUG_CURL
  32 // #define DEBUG_VERBOSE
  33
  34 #ifdef DEBUG_CURL
  35 #define DPRINTF(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)
  36 #else
  37 #define DPRINTF(fmt, ...) do { } while (0)
  38 #endif
  39
  40 #if LIBCURL_VERSION_NUM >= 0x071000
  41 /* The multi interface timer callback was introduced in 7.16.0 */
  42 #define NEED_CURL_TIMER_CALLBACK
  43 #define HAVE_SOCKET_ACTION
  44 #endif
  45
  46 #ifndef HAVE_SOCKET_ACTION
  47 /* If curl_multi_socket_action isn't available, define it statically here in
  48  * terms of curl_multi_socket. Note that ev_bitmask will be ignored, which is
  49  * less efficient but still safe. */
  50 static CURLMcode __curl_multi_socket_action(CURLM *multi_handle,
  51                                             curl_socket_t sockfd,
  52                                             int ev_bitmask,
  53                                             int *running_handles)
  54 {
  55     return curl_multi_socket(multi_handle, sockfd, running_handles);
  56 }
  57 #define curl_multi_socket_action __curl_multi_socket_action
  58 #endif
  59
  60 #define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \
  61                    CURLPROTO_FTP | CURLPROTO_FTPS | \
  62                    CURLPROTO_TFTP)
  63
  64 #define CURL_NUM_STATES 8
  65 #define CURL_NUM_ACB    8
  66 #define SECTOR_SIZE     512
  67 #define READ_AHEAD_DEFAULT (256 * 1024)
  68 #define CURL_TIMEOUT_DEFAULT 5
  69 #define CURL_TIMEOUT_MAX 10000
  70
  71 #define FIND_RET_NONE   0
  72 #define FIND_RET_OK     1
  73 #define FIND_RET_WAIT   2
  74
  75 #define CURL_BLOCK_OPT_URL       "url"
  76 #define CURL_BLOCK_OPT_READAHEAD "readahead"
  77 #define CURL_BLOCK_OPT_SSLVERIFY "sslverify"
  78 #define CURL_BLOCK_OPT_TIMEOUT "timeout"
  79 #define CURL_BLOCK_OPT_COOKIE    "cookie"
  80
  81 struct BDRVCURLState;
  82
  83 typedef struct CURLAIOCB {
  84     BlockAIOCB common;
  85     QEMUBH *bh;
  86     QEMUIOVector *qiov;
  87
  88     int64_t sector_num;
  89     int nb_sectors;
  90
  91     size_t start;
  92     size_t end;
  93 } CURLAIOCB;
  94
  95 typedef struct CURLState
  96 {
  97     struct BDRVCURLState *s;
  98     CURLAIOCB *acb[CURL_NUM_ACB];
  99     CURL *curl;
 100     curl_socket_t sock_fd;
 101     char *orig_buf;
 102     size_t buf_start;
 103     size_t buf_off;
 104     size_t buf_len;
 105     char range[128];
 106     char errmsg[CURL_ERROR_SIZE];
 107     char in_use;
 108 } CURLState;
 109
 110 typedef struct BDRVCURLState {
 111     CURLM *multi;
 112     QEMUTimer timer;
 113     size_t len;
 114     CURLState states[CURL_NUM_STATES];
 115     char *url;
 116     size_t readahead_size;
 117     bool sslverify;
 118     uint64_t timeout;
 119     char *cookie;
 120     bool accept_range;
 121     AioContext *aio_context;
 122 } BDRVCURLState;
 123
 124 static void curl_clean_state(CURLState *s);
 125 static void curl_multi_do(void *arg);
 126 static void curl_multi_read(void *arg);
 127
 128 #ifdef NEED_CURL_TIMER_CALLBACK
 129 static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
 130 {
 131     BDRVCURLState *s = opaque;
 132
 133     DPRINTF("CURL: timer callback timeout_ms %ld\n", timeout_ms);
 134     if (timeout_ms == -1) {
 135         timer_del(&s->timer);
 136     } else {
 137         int64_t timeout_ns = (int64_t)timeout_ms * 1000 * 1000;
 138         timer_mod(&s->timer,
 139                   qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ns);
 140     }
 141     return 0;
 142 }
 143 #endif
 144
 145 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
 146                         void *userp, void *sp)
 147 {
 148     BDRVCURLState *s;
 149     CURLState *state = NULL;
 150     curl_easy_getinfo(curl, CURLINFO_PRIVATE, (char **)&state);
 151     state->sock_fd = fd;
 152     s = state->s;
 153
 154     DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
 155     switch (action) {
 156         case CURL_POLL_IN:
 157             aio_set_fd_handler(s->aio_context, fd, curl_multi_read,
 158                                NULL, state);
 159             break;
 160         case CURL_POLL_OUT:
 161             aio_set_fd_handler(s->aio_context, fd, NULL, curl_multi_do, state);
 162             break;
 163         case CURL_POLL_INOUT:
 164             aio_set_fd_handler(s->aio_context, fd, curl_multi_read,
 165                                curl_multi_do, state);
 166             break;
 167         case CURL_POLL_REMOVE:
 168             aio_set_fd_handler(s->aio_context, fd, NULL, NULL, NULL);
 169             break;
 170     }
 171
 172     return 0;
 173 }
 174
 175 static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 176 {
 177     BDRVCURLState *s = opaque;
 178     size_t realsize = size * nmemb;
 179     const char *accept_line = "Accept-Ranges: bytes";
 180
 181     if (realsize >= strlen(accept_line)
 182         && strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
 183         s->accept_range = true;
 184     }
 185
 186     return realsize;
 187 }
 188
 189 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 190 {
 191     CURLState *s = ((CURLState*)opaque);
 192     size_t realsize = size * nmemb;
 193     int i;
 194
 195     DPRINTF("CURL: Just reading %zd bytes\n", realsize);
 196
 197     if (!s || !s->orig_buf)
 198         return 0;
 199
 200     if (s->buf_off >= s->buf_len) {
 201         /* buffer full, read nothing */
 202         return 0;
 203     }
 204     realsize = MIN(realsize, s->buf_len - s->buf_off);
 205     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 206     s->buf_off += realsize;
 207
 208     for(i=0; i<CURL_NUM_ACB; i++) {
 209         CURLAIOCB *acb = s->acb[i];
 210
 211         if (!acb)
 212             continue;
 213
 214         if ((s->buf_off >= acb->end)) {
 215             qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start,
 216                                 acb->end - acb->start);
 217             acb->common.cb(acb->common.opaque, 0);
 218             qemu_aio_unref(acb);
 219             s->acb[i] = NULL;
 220         }
 221     }
 222
 223     return realsize;
 224 }
 225
 226 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
 227                          CURLAIOCB *acb)
 228 {
 229     int i;
 230     size_t end = start + len;
 231
 232     for (i=0; i<CURL_NUM_STATES; i++) {
 233         CURLState *state = &s->states[i];
 234         size_t buf_end = (state->buf_start + state->buf_off);
 235         size_t buf_fend = (state->buf_start + state->buf_len);
 236
 237         if (!state->orig_buf)
 238             continue;
 239         if (!state->buf_off)
 240             continue;
 241
 242         // Does the existing buffer cover our section?
 243         if ((start >= state->buf_start) &&
 244             (start <= buf_end) &&
 245             (end >= state->buf_start) &&
 246             (end <= buf_end))
 247         {
 248             char *buf = state->orig_buf + (start - state->buf_start);
 249
 250             qemu_iovec_from_buf(acb->qiov, 0, buf, len);
 251             acb->common.cb(acb->common.opaque, 0);
 252
 253             return FIND_RET_OK;
 254         }
 255
 256         // Wait for unfinished chunks
 257         if (state->in_use &&
 258             (start >= state->buf_start) &&
 259             (start <= buf_fend) &&
 260             (end >= state->buf_start) &&
 261             (end <= buf_fend))
 262         {
 263             int j;
 264
 265             acb->start = start - state->buf_start;
 266             acb->end = acb->start + len;
 267
 268             for (j=0; j<CURL_NUM_ACB; j++) {
 269                 if (!state->acb[j]) {
 270                     state->acb[j] = acb;
 271                     return FIND_RET_WAIT;
 272                 }
 273             }
 274         }
 275     }
 276
 277     return FIND_RET_NONE;
 278 }
 279
 280 static void curl_multi_check_completion(BDRVCURLState *s)
 281 {
 282     int msgs_in_queue;
 283
 284     /* Try to find done transfers, so we can free the easy
 285      * handle again. */
 286     for (;;) {
 287         CURLMsg *msg;
 288         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 289
 290         /* Quit when there are no more completions */
 291         if (!msg)
 292             break;
 293
 294         if (msg->msg == CURLMSG_DONE) {
 295             CURLState *state = NULL;
 296             curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE,
 297                               (char **)&state);
 298
 299             /* ACBs for successful messages get completed in curl_read_cb */
 300             if (msg->data.result != CURLE_OK) {
 301                 int i;
 302                 static int errcount = 100;
 303
 304                 /* Don't lose the original error message from curl, since
 305                  * it contains extra data.
 306                  */
 307                 if (errcount > 0) {
 308                     error_report("curl: %s", state->errmsg);
 309                     if (--errcount == 0) {
 310                         error_report("curl: further errors suppressed");
 311                     }
 312                 }
 313
 314                 for (i = 0; i < CURL_NUM_ACB; i++) {
 315                     CURLAIOCB *acb = state->acb[i];
 316
 317                     if (acb == NULL) {
 318                         continue;
 319                     }
 320
 321                     acb->common.cb(acb->common.opaque, -EPROTO);
 322                     qemu_aio_unref(acb);
 323                     state->acb[i] = NULL;
 324                 }
 325             }
 326
 327             curl_clean_state(state);
 328             break;
 329         }
 330     }
 331 }
 332
 333 static void curl_multi_do(void *arg)
 334 {
 335     CURLState *s = (CURLState *)arg;
 336     int running;
 337     int r;
 338
 339     if (!s->s->multi) {
 340         return;
 341     }
 342
 343     do {
 344         r = curl_multi_socket_action(s->s->multi, s->sock_fd, 0, &running);
 345     } while(r == CURLM_CALL_MULTI_PERFORM);
 346
 347 }
 348
 349 static void curl_multi_read(void *arg)
 350 {
 351     CURLState *s = (CURLState *)arg;
 352
 353     curl_multi_do(arg);
 354     curl_multi_check_completion(s->s);
 355 }
 356
 357 static void curl_multi_timeout_do(void *arg)
 358 {
 359 #ifdef NEED_CURL_TIMER_CALLBACK
 360     BDRVCURLState *s = (BDRVCURLState *)arg;
 361     int running;
 362
 363     if (!s->multi) {
 364         return;
 365     }
 366
 367     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 368
 369     curl_multi_check_completion(s);
 370 #else
 371     abort();
 372 #endif
 373 }
 374
 375 static CURLState *curl_init_state(BlockDriverState *bs, BDRVCURLState *s)
 376 {
 377     CURLState *state = NULL;
 378     int i, j;
 379
 380     do {
 381         for (i=0; i<CURL_NUM_STATES; i++) {
 382             for (j=0; j<CURL_NUM_ACB; j++)
 383                 if (s->states[i].acb[j])
 384                     continue;
 385             if (s->states[i].in_use)
 386                 continue;
 387
 388             state = &s->states[i];
 389             state->in_use = 1;
 390             break;
 391         }
 392         if (!state) {
 393             aio_poll(bdrv_get_aio_context(bs), true);
 394         }
 395     } while(!state);
 396
 397     if (!state->curl) {
 398         state->curl = curl_easy_init();
 399         if (!state->curl) {
 400             return NULL;
 401         }
 402         curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 403         curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYPEER,
 404                          (long) s->sslverify);
 405         if (s->cookie) {
 406             curl_easy_setopt(state->curl, CURLOPT_COOKIE, s->cookie);
 407         }
 408         curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, (long)s->timeout);
 409         curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION,
 410                          (void *)curl_read_cb);
 411         curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 412         curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 413         curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 414         curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 415         curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 416         curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 417         curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
 418
 419         /* Restrict supported protocols to avoid security issues in the more
 420          * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see
 421          * CVE-2013-0249.
 422          *
 423          * Restricting protocols is only supported from 7.19.4 upwards.
 424          */
 425 #if LIBCURL_VERSION_NUM >= 0x071304
 426         curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);
 427         curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);
 428 #endif
 429
 430 #ifdef DEBUG_VERBOSE
 431         curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 432 #endif
 433     }
 434
 435     state->s = s;
 436
 437     return state;
 438 }
 439
 440 static void curl_clean_state(CURLState *s)
 441 {
 442     if (s->s->multi)
 443         curl_multi_remove_handle(s->s->multi, s->curl);
 444     s->in_use = 0;
 445 }
 446
 447 static void curl_parse_filename(const char *filename, QDict *options,
 448                                 Error **errp)
 449 {
 450     qdict_put(options, CURL_BLOCK_OPT_URL, qstring_from_str(filename));
 451 }
 452
 453 static void curl_detach_aio_context(BlockDriverState *bs)
 454 {
 455     BDRVCURLState *s = bs->opaque;
 456     int i;
 457
 458     for (i = 0; i < CURL_NUM_STATES; i++) {
 459         if (s->states[i].in_use) {
 460             curl_clean_state(&s->states[i]);
 461         }
 462         if (s->states[i].curl) {
 463             curl_easy_cleanup(s->states[i].curl);
 464             s->states[i].curl = NULL;
 465         }
 466         g_free(s->states[i].orig_buf);
 467         s->states[i].orig_buf = NULL;
 468     }
 469     if (s->multi) {
 470         curl_multi_cleanup(s->multi);
 471         s->multi = NULL;
 472     }
 473
 474     timer_del(&s->timer);
 475 }
 476
 477 static void curl_attach_aio_context(BlockDriverState *bs,
 478                                     AioContext *new_context)
 479 {
 480     BDRVCURLState *s = bs->opaque;
 481
 482     aio_timer_init(new_context, &s->timer,
 483                    QEMU_CLOCK_REALTIME, SCALE_NS,
 484                    curl_multi_timeout_do, s);
 485
 486     assert(!s->multi);
 487     s->multi = curl_multi_init();
 488     s->aio_context = new_context;
 489     curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
 490 #ifdef NEED_CURL_TIMER_CALLBACK
 491     curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
 492     curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
 493 #endif
 494 }
 495
 496 static QemuOptsList runtime_opts = {
 497     .name = "curl",
 498     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 499     .desc = {
 500         {
 501             .name = CURL_BLOCK_OPT_URL,
 502             .type = QEMU_OPT_STRING,
 503             .help = "URL to open",
 504         },
 505         {
 506             .name = CURL_BLOCK_OPT_READAHEAD,
 507             .type = QEMU_OPT_SIZE,
 508             .help = "Readahead size",
 509         },
 510         {
 511             .name = CURL_BLOCK_OPT_SSLVERIFY,
 512             .type = QEMU_OPT_BOOL,
 513             .help = "Verify SSL certificate"
 514         },
 515         {
 516             .name = CURL_BLOCK_OPT_TIMEOUT,
 517             .type = QEMU_OPT_NUMBER,
 518             .help = "Curl timeout"
 519         },
 520         {
 521             .name = CURL_BLOCK_OPT_COOKIE,
 522             .type = QEMU_OPT_STRING,
 523             .help = "Pass the cookie or list of cookies with each request"
 524         },
 525         { /* end of list */ }
 526     },
 527 };
 528
 529 static int curl_open(BlockDriverState *bs, QDict *options, int flags,
 530                      Error **errp)
 531 {
 532     BDRVCURLState *s = bs->opaque;
 533     CURLState *state = NULL;
 534     QemuOpts *opts;
 535     Error *local_err = NULL;
 536     const char *file;
 537     const char *cookie;
 538     double d;
 539
 540     static int inited = 0;
 541
 542     if (flags & BDRV_O_RDWR) {
 543         error_setg(errp, "curl block device does not support writes");
 544         return -EROFS;
 545     }
 546
 547     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 548     qemu_opts_absorb_qdict(opts, options, &local_err);
 549     if (local_err) {
 550         error_propagate(errp, local_err);
 551         goto out_noclean;
 552     }
 553
 554     s->readahead_size = qemu_opt_get_size(opts, CURL_BLOCK_OPT_READAHEAD,
 555                                           READ_AHEAD_DEFAULT);
 556     if ((s->readahead_size & 0x1ff) != 0) {
 557         error_setg(errp, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512",
 558                    s->readahead_size);
 559         goto out_noclean;
 560     }
 561
 562     s->timeout = qemu_opt_get_number(opts, CURL_BLOCK_OPT_TIMEOUT,
 563                                      CURL_TIMEOUT_DEFAULT);
 564     if (s->timeout > CURL_TIMEOUT_MAX) {
 565         error_setg(errp, "timeout parameter is too large or negative");
 566         goto out_noclean;
 567     }
 568
 569     s->sslverify = qemu_opt_get_bool(opts, CURL_BLOCK_OPT_SSLVERIFY, true);
 570
 571     cookie = qemu_opt_get(opts, CURL_BLOCK_OPT_COOKIE);
 572     s->cookie = g_strdup(cookie);
 573
 574     file = qemu_opt_get(opts, CURL_BLOCK_OPT_URL);
 575     if (file == NULL) {
 576         error_setg(errp, "curl block driver requires an 'url' option");
 577         goto out_noclean;
 578     }
 579
 580     if (!inited) {
 581         curl_global_init(CURL_GLOBAL_ALL);
 582         inited = 1;
 583     }
 584
 585     DPRINTF("CURL: Opening %s\n", file);
 586     s->aio_context = bdrv_get_aio_context(bs);
 587     s->url = g_strdup(file);
 588     state = curl_init_state(bs, s);
 589     if (!state)
 590         goto out_noclean;
 591
 592     // Get file size
 593
 594     s->accept_range = false;
 595     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 596     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
 597                      curl_header_cb);
 598     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
 599     if (curl_easy_perform(state->curl))
 600         goto out;
 601     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 602     if (d)
 603         s->len = (size_t)d;
 604     else if(!s->len)
 605         goto out;
 606     if ((!strncasecmp(s->url, "http://", strlen("http://"))
 607         || !strncasecmp(s->url, "https://", strlen("https://")))
 608         && !s->accept_range) {
 609         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
 610                 "Server does not support 'range' (byte ranges).");
 611         goto out;
 612     }
 613     DPRINTF("CURL: Size = %zd\n", s->len);
 614
 615     curl_clean_state(state);
 616     curl_easy_cleanup(state->curl);
 617     state->curl = NULL;
 618
 619     curl_attach_aio_context(bs, bdrv_get_aio_context(bs));
 620
 621     qemu_opts_del(opts);
 622     return 0;
 623
 624 out:
 625     error_setg(errp, "CURL: Error opening file: %s", state->errmsg);
 626     curl_easy_cleanup(state->curl);
 627     state->curl = NULL;
 628 out_noclean:
 629     g_free(s->cookie);
 630     g_free(s->url);
 631     qemu_opts_del(opts);
 632     return -EINVAL;
 633 }
 634
 635 static const AIOCBInfo curl_aiocb_info = {
 636     .aiocb_size         = sizeof(CURLAIOCB),
 637 };
 638
 639
 640 static void curl_readv_bh_cb(void *p)
 641 {
 642     CURLState *state;
 643     int running;
 644
 645     CURLAIOCB *acb = p;
 646     BDRVCURLState *s = acb->common.bs->opaque;
 647
 648     qemu_bh_delete(acb->bh);
 649     acb->bh = NULL;
 650
 651     size_t start = acb->sector_num * SECTOR_SIZE;
 652     size_t end;
 653
 654     // In case we have the requested data already (e.g. read-ahead),
 655     // we can just call the callback and be done.
 656     switch (curl_find_buf(s, start, acb->nb_sectors * SECTOR_SIZE, acb)) {
 657         case FIND_RET_OK:
 658             qemu_aio_unref(acb);
 659             // fall through
 660         case FIND_RET_WAIT:
 661             return;
 662         default:
 663             break;
 664     }
 665
 666     // No cache found, so let's start a new request
 667     state = curl_init_state(acb->common.bs, s);
 668     if (!state) {
 669         acb->common.cb(acb->common.opaque, -EIO);
 670         qemu_aio_unref(acb);
 671         return;
 672     }
 673
 674     acb->start = 0;
 675     acb->end = (acb->nb_sectors * SECTOR_SIZE);
 676
 677     state->buf_off = 0;
 678     g_free(state->orig_buf);
 679     state->buf_start = start;
 680     state->buf_len = acb->end + s->readahead_size;
 681     end = MIN(start + state->buf_len, s->len) - 1;
 682     state->orig_buf = g_try_malloc(state->buf_len);
 683     if (state->buf_len && state->orig_buf == NULL) {
 684         curl_clean_state(state);
 685         acb->common.cb(acb->common.opaque, -ENOMEM);
 686         qemu_aio_unref(acb);
 687         return;
 688     }
 689     state->acb[0] = acb;
 690
 691     snprintf(state->range, 127, "%zd-%zd", start, end);
 692     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
 693             (acb->nb_sectors * SECTOR_SIZE), start, state->range);
 694     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 695
 696     curl_multi_add_handle(s->multi, state->curl);
 697
 698     /* Tell curl it needs to kick things off */
 699     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 700 }
 701
 702 static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
 703         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 704         BlockCompletionFunc *cb, void *opaque)
 705 {
 706     CURLAIOCB *acb;
 707
 708     acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);
 709
 710     acb->qiov = qiov;
 711     acb->sector_num = sector_num;
 712     acb->nb_sectors = nb_sectors;
 713
 714     acb->bh = aio_bh_new(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
 715     qemu_bh_schedule(acb->bh);
 716     return &acb->common;
 717 }
 718
 719 static void curl_close(BlockDriverState *bs)
 720 {
 721     BDRVCURLState *s = bs->opaque;
 722
 723     DPRINTF("CURL: Close\n");
 724     curl_detach_aio_context(bs);
 725
 726     g_free(s->cookie);
 727     g_free(s->url);
 728 }
 729
 730 static int64_t curl_getlength(BlockDriverState *bs)
 731 {
 732     BDRVCURLState *s = bs->opaque;
 733     return s->len;
 734 }
 735
 736 static BlockDriver bdrv_http = {
 737     .format_name                = "http",
 738     .protocol_name              = "http",
 739
 740     .instance_size              = sizeof(BDRVCURLState),
 741     .bdrv_parse_filename        = curl_parse_filename,
 742     .bdrv_file_open             = curl_open,
 743     .bdrv_close                 = curl_close,
 744     .bdrv_getlength             = curl_getlength,
 745
 746     .bdrv_aio_readv             = curl_aio_readv,
 747
 748     .bdrv_detach_aio_context    = curl_detach_aio_context,
 749     .bdrv_attach_aio_context    = curl_attach_aio_context,
 750 };
 751
 752 static BlockDriver bdrv_https = {
 753     .format_name                = "https",
 754     .protocol_name              = "https",
 755
 756     .instance_size              = sizeof(BDRVCURLState),
 757     .bdrv_parse_filename        = curl_parse_filename,
 758     .bdrv_file_open             = curl_open,
 759     .bdrv_close                 = curl_close,
 760     .bdrv_getlength             = curl_getlength,
 761
 762     .bdrv_aio_readv             = curl_aio_readv,
 763
 764     .bdrv_detach_aio_context    = curl_detach_aio_context,
 765     .bdrv_attach_aio_context    = curl_attach_aio_context,
 766 };
 767
 768 static BlockDriver bdrv_ftp = {
 769     .format_name                = "ftp",
 770     .protocol_name              = "ftp",
 771
 772     .instance_size              = sizeof(BDRVCURLState),
 773     .bdrv_parse_filename        = curl_parse_filename,
 774     .bdrv_file_open             = curl_open,
 775     .bdrv_close                 = curl_close,
 776     .bdrv_getlength             = curl_getlength,
 777
 778     .bdrv_aio_readv             = curl_aio_readv,
 779
 780     .bdrv_detach_aio_context    = curl_detach_aio_context,
 781     .bdrv_attach_aio_context    = curl_attach_aio_context,
 782 };
 783
 784 static BlockDriver bdrv_ftps = {
 785     .format_name                = "ftps",
 786     .protocol_name              = "ftps",
 787
 788     .instance_size              = sizeof(BDRVCURLState),
 789     .bdrv_parse_filename        = curl_parse_filename,
 790     .bdrv_file_open             = curl_open,
 791     .bdrv_close                 = curl_close,
 792     .bdrv_getlength             = curl_getlength,
 793
 794     .bdrv_aio_readv             = curl_aio_readv,
 795
 796     .bdrv_detach_aio_context    = curl_detach_aio_context,
 797     .bdrv_attach_aio_context    = curl_attach_aio_context,
 798 };
 799
 800 static BlockDriver bdrv_tftp = {
 801     .format_name                = "tftp",
 802     .protocol_name              = "tftp",
 803
 804     .instance_size              = sizeof(BDRVCURLState),
 805     .bdrv_parse_filename        = curl_parse_filename,
 806     .bdrv_file_open             = curl_open,
 807     .bdrv_close                 = curl_close,
 808     .bdrv_getlength             = curl_getlength,
 809
 810     .bdrv_aio_readv             = curl_aio_readv,
 811
 812     .bdrv_detach_aio_context    = curl_detach_aio_context,
 813     .bdrv_attach_aio_context    = curl_attach_aio_context,
 814 };
 815
 816 static void curl_block_init(void)
 817 {
 818     bdrv_register(&bdrv_http);
 819     bdrv_register(&bdrv_https);
 820     bdrv_register(&bdrv_ftp);
 821     bdrv_register(&bdrv_ftps);
 822     bdrv_register(&bdrv_tftp);
 823 }
 824
 825 block_init(curl_block_init);