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/osdep.h"
  25 #include "qemu-common.h"
  26 #include "qemu/error-report.h"
  27 #include "block/block_int.h"
  28 #include "qapi/qmp/qbool.h"
  29 #include "qapi/qmp/qstring.h"
  30 #include <curl/curl.h>
  31
  32 // #define DEBUG_CURL
  33 // #define DEBUG_VERBOSE
  34
  35 #ifdef DEBUG_CURL
  36 #define DPRINTF(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)
  37 #else
  38 #define DPRINTF(fmt, ...) do { } while (0)
  39 #endif
  40
  41 #if LIBCURL_VERSION_NUM >= 0x071000
  42 /* The multi interface timer callback was introduced in 7.16.0 */
  43 #define NEED_CURL_TIMER_CALLBACK
  44 #define HAVE_SOCKET_ACTION
  45 #endif
  46
  47 #ifndef HAVE_SOCKET_ACTION
  48 /* If curl_multi_socket_action isn't available, define it statically here in
  49  * terms of curl_multi_socket. Note that ev_bitmask will be ignored, which is
  50  * less efficient but still safe. */
  51 static CURLMcode __curl_multi_socket_action(CURLM *multi_handle,
  52                                             curl_socket_t sockfd,
  53                                             int ev_bitmask,
  54                                             int *running_handles)
  55 {
  56     return curl_multi_socket(multi_handle, sockfd, running_handles);
  57 }
  58 #define curl_multi_socket_action __curl_multi_socket_action
  59 #endif
  60
  61 #define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \
  62                    CURLPROTO_FTP | CURLPROTO_FTPS | \
  63                    CURLPROTO_TFTP)
  64
  65 #define CURL_NUM_STATES 8
  66 #define CURL_NUM_ACB    8
  67 #define SECTOR_SIZE     512
  68 #define READ_AHEAD_DEFAULT (256 * 1024)
  69 #define CURL_TIMEOUT_DEFAULT 5
  70 #define CURL_TIMEOUT_MAX 10000
  71
  72 #define FIND_RET_NONE   0
  73 #define FIND_RET_OK     1
  74 #define FIND_RET_WAIT   2
  75
  76 #define CURL_BLOCK_OPT_URL       "url"
  77 #define CURL_BLOCK_OPT_READAHEAD "readahead"
  78 #define CURL_BLOCK_OPT_SSLVERIFY "sslverify"
  79 #define CURL_BLOCK_OPT_TIMEOUT "timeout"
  80 #define CURL_BLOCK_OPT_COOKIE    "cookie"
  81
  82 struct BDRVCURLState;
  83
  84 typedef struct CURLAIOCB {
  85     BlockAIOCB common;
  86     QEMUBH *bh;
  87     QEMUIOVector *qiov;
  88
  89     int64_t sector_num;
  90     int nb_sectors;
  91
  92     size_t start;
  93     size_t end;
  94 } CURLAIOCB;
  95
  96 typedef struct CURLState
  97 {
  98     struct BDRVCURLState *s;
  99     CURLAIOCB *acb[CURL_NUM_ACB];
 100     CURL *curl;
 101     curl_socket_t sock_fd;
 102     char *orig_buf;
 103     size_t buf_start;
 104     size_t buf_off;
 105     size_t buf_len;
 106     char range[128];
 107     char errmsg[CURL_ERROR_SIZE];
 108     char in_use;
 109 } CURLState;
 110
 111 typedef struct BDRVCURLState {
 112     CURLM *multi;
 113     QEMUTimer timer;
 114     size_t len;
 115     CURLState states[CURL_NUM_STATES];
 116     char *url;
 117     size_t readahead_size;
 118     bool sslverify;
 119     uint64_t timeout;
 120     char *cookie;
 121     bool accept_range;
 122     AioContext *aio_context;
 123 } BDRVCURLState;
 124
 125 static void curl_clean_state(CURLState *s);
 126 static void curl_multi_do(void *arg);
 127 static void curl_multi_read(void *arg);
 128
 129 #ifdef NEED_CURL_TIMER_CALLBACK
 130 static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
 131 {
 132     BDRVCURLState *s = opaque;
 133
 134     DPRINTF("CURL: timer callback timeout_ms %ld\n", timeout_ms);
 135     if (timeout_ms == -1) {
 136         timer_del(&s->timer);
 137     } else {
 138         int64_t timeout_ns = (int64_t)timeout_ms * 1000 * 1000;
 139         timer_mod(&s->timer,
 140                   qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ns);
 141     }
 142     return 0;
 143 }
 144 #endif
 145
 146 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
 147                         void *userp, void *sp)
 148 {
 149     BDRVCURLState *s;
 150     CURLState *state = NULL;
 151     curl_easy_getinfo(curl, CURLINFO_PRIVATE, (char **)&state);
 152     state->sock_fd = fd;
 153     s = state->s;
 154
 155     DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
 156     switch (action) {
 157         case CURL_POLL_IN:
 158             aio_set_fd_handler(s->aio_context, fd, false,
 159                                curl_multi_read, NULL, state);
 160             break;
 161         case CURL_POLL_OUT:
 162             aio_set_fd_handler(s->aio_context, fd, false,
 163                                NULL, curl_multi_do, state);
 164             break;
 165         case CURL_POLL_INOUT:
 166             aio_set_fd_handler(s->aio_context, fd, false,
 167                                curl_multi_read, curl_multi_do, state);
 168             break;
 169         case CURL_POLL_REMOVE:
 170             aio_set_fd_handler(s->aio_context, fd, false,
 171                                NULL, NULL, NULL);
 172             break;
 173     }
 174
 175     return 0;
 176 }
 177
 178 static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 179 {
 180     BDRVCURLState *s = opaque;
 181     size_t realsize = size * nmemb;
 182     const char *accept_line = "Accept-Ranges: bytes";
 183
 184     if (realsize >= strlen(accept_line)
 185         && strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
 186         s->accept_range = true;
 187     }
 188
 189     return realsize;
 190 }
 191
 192 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 193 {
 194     CURLState *s = ((CURLState*)opaque);
 195     size_t realsize = size * nmemb;
 196     int i;
 197
 198     DPRINTF("CURL: Just reading %zd bytes\n", realsize);
 199
 200     if (!s || !s->orig_buf)
 201         return 0;
 202
 203     if (s->buf_off >= s->buf_len) {
 204         /* buffer full, read nothing */
 205         return 0;
 206     }
 207     realsize = MIN(realsize, s->buf_len - s->buf_off);
 208     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 209     s->buf_off += realsize;
 210
 211     for(i=0; i<CURL_NUM_ACB; i++) {
 212         CURLAIOCB *acb = s->acb[i];
 213
 214         if (!acb)
 215             continue;
 216
 217         if ((s->buf_off >= acb->end)) {
 218             qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start,
 219                                 acb->end - acb->start);
 220             acb->common.cb(acb->common.opaque, 0);
 221             qemu_aio_unref(acb);
 222             s->acb[i] = NULL;
 223         }
 224     }
 225
 226     return realsize;
 227 }
 228
 229 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
 230                          CURLAIOCB *acb)
 231 {
 232     int i;
 233     size_t end = start + len;
 234
 235     for (i=0; i<CURL_NUM_STATES; i++) {
 236         CURLState *state = &s->states[i];
 237         size_t buf_end = (state->buf_start + state->buf_off);
 238         size_t buf_fend = (state->buf_start + state->buf_len);
 239
 240         if (!state->orig_buf)
 241             continue;
 242         if (!state->buf_off)
 243             continue;
 244
 245         // Does the existing buffer cover our section?
 246         if ((start >= state->buf_start) &&
 247             (start <= buf_end) &&
 248             (end >= state->buf_start) &&
 249             (end <= buf_end))
 250         {
 251             char *buf = state->orig_buf + (start - state->buf_start);
 252
 253             qemu_iovec_from_buf(acb->qiov, 0, buf, len);
 254             acb->common.cb(acb->common.opaque, 0);
 255
 256             return FIND_RET_OK;
 257         }
 258
 259         // Wait for unfinished chunks
 260         if (state->in_use &&
 261             (start >= state->buf_start) &&
 262             (start <= buf_fend) &&
 263             (end >= state->buf_start) &&
 264             (end <= buf_fend))
 265         {
 266             int j;
 267
 268             acb->start = start - state->buf_start;
 269             acb->end = acb->start + len;
 270
 271             for (j=0; j<CURL_NUM_ACB; j++) {
 272                 if (!state->acb[j]) {
 273                     state->acb[j] = acb;
 274                     return FIND_RET_WAIT;
 275                 }
 276             }
 277         }
 278     }
 279
 280     return FIND_RET_NONE;
 281 }
 282
 283 static void curl_multi_check_completion(BDRVCURLState *s)
 284 {
 285     int msgs_in_queue;
 286
 287     /* Try to find done transfers, so we can free the easy
 288      * handle again. */
 289     for (;;) {
 290         CURLMsg *msg;
 291         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 292
 293         /* Quit when there are no more completions */
 294         if (!msg)
 295             break;
 296
 297         if (msg->msg == CURLMSG_DONE) {
 298             CURLState *state = NULL;
 299             curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE,
 300                               (char **)&state);
 301
 302             /* ACBs for successful messages get completed in curl_read_cb */
 303             if (msg->data.result != CURLE_OK) {
 304                 int i;
 305                 static int errcount = 100;
 306
 307                 /* Don't lose the original error message from curl, since
 308                  * it contains extra data.
 309                  */
 310                 if (errcount > 0) {
 311                     error_report("curl: %s", state->errmsg);
 312                     if (--errcount == 0) {
 313                         error_report("curl: further errors suppressed");
 314                     }
 315                 }
 316
 317                 for (i = 0; i < CURL_NUM_ACB; i++) {
 318                     CURLAIOCB *acb = state->acb[i];
 319
 320                     if (acb == NULL) {
 321                         continue;
 322                     }
 323
 324                     acb->common.cb(acb->common.opaque, -EPROTO);
 325                     qemu_aio_unref(acb);
 326                     state->acb[i] = NULL;
 327                 }
 328             }
 329
 330             curl_clean_state(state);
 331             break;
 332         }
 333     }
 334 }
 335
 336 static void curl_multi_do(void *arg)
 337 {
 338     CURLState *s = (CURLState *)arg;
 339     int running;
 340     int r;
 341
 342     if (!s->s->multi) {
 343         return;
 344     }
 345
 346     do {
 347         r = curl_multi_socket_action(s->s->multi, s->sock_fd, 0, &running);
 348     } while(r == CURLM_CALL_MULTI_PERFORM);
 349
 350 }
 351
 352 static void curl_multi_read(void *arg)
 353 {
 354     CURLState *s = (CURLState *)arg;
 355
 356     curl_multi_do(arg);
 357     curl_multi_check_completion(s->s);
 358 }
 359
 360 static void curl_multi_timeout_do(void *arg)
 361 {
 362 #ifdef NEED_CURL_TIMER_CALLBACK
 363     BDRVCURLState *s = (BDRVCURLState *)arg;
 364     int running;
 365
 366     if (!s->multi) {
 367         return;
 368     }
 369
 370     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 371
 372     curl_multi_check_completion(s);
 373 #else
 374     abort();
 375 #endif
 376 }
 377
 378 static CURLState *curl_init_state(BlockDriverState *bs, BDRVCURLState *s)
 379 {
 380     CURLState *state = NULL;
 381     int i, j;
 382
 383     do {
 384         for (i=0; i<CURL_NUM_STATES; i++) {
 385             for (j=0; j<CURL_NUM_ACB; j++)
 386                 if (s->states[i].acb[j])
 387                     continue;
 388             if (s->states[i].in_use)
 389                 continue;
 390
 391             state = &s->states[i];
 392             state->in_use = 1;
 393             break;
 394         }
 395         if (!state) {
 396             aio_poll(bdrv_get_aio_context(bs), true);
 397         }
 398     } while(!state);
 399
 400     if (!state->curl) {
 401         state->curl = curl_easy_init();
 402         if (!state->curl) {
 403             return NULL;
 404         }
 405         curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 406         curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYPEER,
 407                          (long) s->sslverify);
 408         if (s->cookie) {
 409             curl_easy_setopt(state->curl, CURLOPT_COOKIE, s->cookie);
 410         }
 411         curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, (long)s->timeout);
 412         curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION,
 413                          (void *)curl_read_cb);
 414         curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 415         curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 416         curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 417         curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 418         curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 419         curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 420         curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
 421
 422         /* Restrict supported protocols to avoid security issues in the more
 423          * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see
 424          * CVE-2013-0249.
 425          *
 426          * Restricting protocols is only supported from 7.19.4 upwards.
 427          */
 428 #if LIBCURL_VERSION_NUM >= 0x071304
 429         curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);
 430         curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);
 431 #endif
 432
 433 #ifdef DEBUG_VERBOSE
 434         curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 435 #endif
 436     }
 437
 438     state->s = s;
 439
 440     return state;
 441 }
 442
 443 static void curl_clean_state(CURLState *s)
 444 {
 445     if (s->s->multi)
 446         curl_multi_remove_handle(s->s->multi, s->curl);
 447     s->in_use = 0;
 448 }
 449
 450 static void curl_parse_filename(const char *filename, QDict *options,
 451                                 Error **errp)
 452 {
 453     qdict_put(options, CURL_BLOCK_OPT_URL, qstring_from_str(filename));
 454 }
 455
 456 static void curl_detach_aio_context(BlockDriverState *bs)
 457 {
 458     BDRVCURLState *s = bs->opaque;
 459     int i;
 460
 461     for (i = 0; i < CURL_NUM_STATES; i++) {
 462         if (s->states[i].in_use) {
 463             curl_clean_state(&s->states[i]);
 464         }
 465         if (s->states[i].curl) {
 466             curl_easy_cleanup(s->states[i].curl);
 467             s->states[i].curl = NULL;
 468         }
 469         g_free(s->states[i].orig_buf);
 470         s->states[i].orig_buf = NULL;
 471     }
 472     if (s->multi) {
 473         curl_multi_cleanup(s->multi);
 474         s->multi = NULL;
 475     }
 476
 477     timer_del(&s->timer);
 478 }
 479
 480 static void curl_attach_aio_context(BlockDriverState *bs,
 481                                     AioContext *new_context)
 482 {
 483     BDRVCURLState *s = bs->opaque;
 484
 485     aio_timer_init(new_context, &s->timer,
 486                    QEMU_CLOCK_REALTIME, SCALE_NS,
 487                    curl_multi_timeout_do, s);
 488
 489     assert(!s->multi);
 490     s->multi = curl_multi_init();
 491     s->aio_context = new_context;
 492     curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
 493 #ifdef NEED_CURL_TIMER_CALLBACK
 494     curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
 495     curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
 496 #endif
 497 }
 498
 499 static QemuOptsList runtime_opts = {
 500     .name = "curl",
 501     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 502     .desc = {
 503         {
 504             .name = CURL_BLOCK_OPT_URL,
 505             .type = QEMU_OPT_STRING,
 506             .help = "URL to open",
 507         },
 508         {
 509             .name = CURL_BLOCK_OPT_READAHEAD,
 510             .type = QEMU_OPT_SIZE,
 511             .help = "Readahead size",
 512         },
 513         {
 514             .name = CURL_BLOCK_OPT_SSLVERIFY,
 515             .type = QEMU_OPT_BOOL,
 516             .help = "Verify SSL certificate"
 517         },
 518         {
 519             .name = CURL_BLOCK_OPT_TIMEOUT,
 520             .type = QEMU_OPT_NUMBER,
 521             .help = "Curl timeout"
 522         },
 523         {
 524             .name = CURL_BLOCK_OPT_COOKIE,
 525             .type = QEMU_OPT_STRING,
 526             .help = "Pass the cookie or list of cookies with each request"
 527         },
 528         { /* end of list */ }
 529     },
 530 };
 531
 532 static int curl_open(BlockDriverState *bs, QDict *options, int flags,
 533                      Error **errp)
 534 {
 535     BDRVCURLState *s = bs->opaque;
 536     CURLState *state = NULL;
 537     QemuOpts *opts;
 538     Error *local_err = NULL;
 539     const char *file;
 540     const char *cookie;
 541     double d;
 542
 543     static int inited = 0;
 544
 545     if (flags & BDRV_O_RDWR) {
 546         error_setg(errp, "curl block device does not support writes");
 547         return -EROFS;
 548     }
 549
 550     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 551     qemu_opts_absorb_qdict(opts, options, &local_err);
 552     if (local_err) {
 553         error_propagate(errp, local_err);
 554         goto out_noclean;
 555     }
 556
 557     s->readahead_size = qemu_opt_get_size(opts, CURL_BLOCK_OPT_READAHEAD,
 558                                           READ_AHEAD_DEFAULT);
 559     if ((s->readahead_size & 0x1ff) != 0) {
 560         error_setg(errp, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512",
 561                    s->readahead_size);
 562         goto out_noclean;
 563     }
 564
 565     s->timeout = qemu_opt_get_number(opts, CURL_BLOCK_OPT_TIMEOUT,
 566                                      CURL_TIMEOUT_DEFAULT);
 567     if (s->timeout > CURL_TIMEOUT_MAX) {
 568         error_setg(errp, "timeout parameter is too large or negative");
 569         goto out_noclean;
 570     }
 571
 572     s->sslverify = qemu_opt_get_bool(opts, CURL_BLOCK_OPT_SSLVERIFY, true);
 573
 574     cookie = qemu_opt_get(opts, CURL_BLOCK_OPT_COOKIE);
 575     s->cookie = g_strdup(cookie);
 576
 577     file = qemu_opt_get(opts, CURL_BLOCK_OPT_URL);
 578     if (file == NULL) {
 579         error_setg(errp, "curl block driver requires an 'url' option");
 580         goto out_noclean;
 581     }
 582
 583     if (!inited) {
 584         curl_global_init(CURL_GLOBAL_ALL);
 585         inited = 1;
 586     }
 587
 588     DPRINTF("CURL: Opening %s\n", file);
 589     s->aio_context = bdrv_get_aio_context(bs);
 590     s->url = g_strdup(file);
 591     state = curl_init_state(bs, s);
 592     if (!state)
 593         goto out_noclean;
 594
 595     // Get file size
 596
 597     s->accept_range = false;
 598     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 599     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
 600                      curl_header_cb);
 601     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
 602     if (curl_easy_perform(state->curl))
 603         goto out;
 604     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 605     if (d)
 606         s->len = (size_t)d;
 607     else if(!s->len)
 608         goto out;
 609     if ((!strncasecmp(s->url, "http://", strlen("http://"))
 610         || !strncasecmp(s->url, "https://", strlen("https://")))
 611         && !s->accept_range) {
 612         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
 613                 "Server does not support 'range' (byte ranges).");
 614         goto out;
 615     }
 616     DPRINTF("CURL: Size = %zd\n", s->len);
 617
 618     curl_clean_state(state);
 619     curl_easy_cleanup(state->curl);
 620     state->curl = NULL;
 621
 622     curl_attach_aio_context(bs, bdrv_get_aio_context(bs));
 623
 624     qemu_opts_del(opts);
 625     return 0;
 626
 627 out:
 628     error_setg(errp, "CURL: Error opening file: %s", state->errmsg);
 629     curl_easy_cleanup(state->curl);
 630     state->curl = NULL;
 631 out_noclean:
 632     g_free(s->cookie);
 633     g_free(s->url);
 634     qemu_opts_del(opts);
 635     return -EINVAL;
 636 }
 637
 638 static const AIOCBInfo curl_aiocb_info = {
 639     .aiocb_size         = sizeof(CURLAIOCB),
 640 };
 641
 642
 643 static void curl_readv_bh_cb(void *p)
 644 {
 645     CURLState *state;
 646     int running;
 647
 648     CURLAIOCB *acb = p;
 649     BDRVCURLState *s = acb->common.bs->opaque;
 650
 651     qemu_bh_delete(acb->bh);
 652     acb->bh = NULL;
 653
 654     size_t start = acb->sector_num * SECTOR_SIZE;
 655     size_t end;
 656
 657     // In case we have the requested data already (e.g. read-ahead),
 658     // we can just call the callback and be done.
 659     switch (curl_find_buf(s, start, acb->nb_sectors * SECTOR_SIZE, acb)) {
 660         case FIND_RET_OK:
 661             qemu_aio_unref(acb);
 662             // fall through
 663         case FIND_RET_WAIT:
 664             return;
 665         default:
 666             break;
 667     }
 668
 669     // No cache found, so let's start a new request
 670     state = curl_init_state(acb->common.bs, s);
 671     if (!state) {
 672         acb->common.cb(acb->common.opaque, -EIO);
 673         qemu_aio_unref(acb);
 674         return;
 675     }
 676
 677     acb->start = 0;
 678     acb->end = (acb->nb_sectors * SECTOR_SIZE);
 679
 680     state->buf_off = 0;
 681     g_free(state->orig_buf);
 682     state->buf_start = start;
 683     state->buf_len = acb->end + s->readahead_size;
 684     end = MIN(start + state->buf_len, s->len) - 1;
 685     state->orig_buf = g_try_malloc(state->buf_len);
 686     if (state->buf_len && state->orig_buf == NULL) {
 687         curl_clean_state(state);
 688         acb->common.cb(acb->common.opaque, -ENOMEM);
 689         qemu_aio_unref(acb);
 690         return;
 691     }
 692     state->acb[0] = acb;
 693
 694     snprintf(state->range, 127, "%zd-%zd", start, end);
 695     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
 696             (acb->nb_sectors * SECTOR_SIZE), start, state->range);
 697     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 698
 699     curl_multi_add_handle(s->multi, state->curl);
 700
 701     /* Tell curl it needs to kick things off */
 702     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 703 }
 704
 705 static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
 706         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 707         BlockCompletionFunc *cb, void *opaque)
 708 {
 709     CURLAIOCB *acb;
 710
 711     acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);
 712
 713     acb->qiov = qiov;
 714     acb->sector_num = sector_num;
 715     acb->nb_sectors = nb_sectors;
 716
 717     acb->bh = aio_bh_new(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
 718     qemu_bh_schedule(acb->bh);
 719     return &acb->common;
 720 }
 721
 722 static void curl_close(BlockDriverState *bs)
 723 {
 724     BDRVCURLState *s = bs->opaque;
 725
 726     DPRINTF("CURL: Close\n");
 727     curl_detach_aio_context(bs);
 728
 729     g_free(s->cookie);
 730     g_free(s->url);
 731 }
 732
 733 static int64_t curl_getlength(BlockDriverState *bs)
 734 {
 735     BDRVCURLState *s = bs->opaque;
 736     return s->len;
 737 }
 738
 739 static BlockDriver bdrv_http = {
 740     .format_name                = "http",
 741     .protocol_name              = "http",
 742
 743     .instance_size              = sizeof(BDRVCURLState),
 744     .bdrv_parse_filename        = curl_parse_filename,
 745     .bdrv_file_open             = curl_open,
 746     .bdrv_close                 = curl_close,
 747     .bdrv_getlength             = curl_getlength,
 748
 749     .bdrv_aio_readv             = curl_aio_readv,
 750
 751     .bdrv_detach_aio_context    = curl_detach_aio_context,
 752     .bdrv_attach_aio_context    = curl_attach_aio_context,
 753 };
 754
 755 static BlockDriver bdrv_https = {
 756     .format_name                = "https",
 757     .protocol_name              = "https",
 758
 759     .instance_size              = sizeof(BDRVCURLState),
 760     .bdrv_parse_filename        = curl_parse_filename,
 761     .bdrv_file_open             = curl_open,
 762     .bdrv_close                 = curl_close,
 763     .bdrv_getlength             = curl_getlength,
 764
 765     .bdrv_aio_readv             = curl_aio_readv,
 766
 767     .bdrv_detach_aio_context    = curl_detach_aio_context,
 768     .bdrv_attach_aio_context    = curl_attach_aio_context,
 769 };
 770
 771 static BlockDriver bdrv_ftp = {
 772     .format_name                = "ftp",
 773     .protocol_name              = "ftp",
 774
 775     .instance_size              = sizeof(BDRVCURLState),
 776     .bdrv_parse_filename        = curl_parse_filename,
 777     .bdrv_file_open             = curl_open,
 778     .bdrv_close                 = curl_close,
 779     .bdrv_getlength             = curl_getlength,
 780
 781     .bdrv_aio_readv             = curl_aio_readv,
 782
 783     .bdrv_detach_aio_context    = curl_detach_aio_context,
 784     .bdrv_attach_aio_context    = curl_attach_aio_context,
 785 };
 786
 787 static BlockDriver bdrv_ftps = {
 788     .format_name                = "ftps",
 789     .protocol_name              = "ftps",
 790
 791     .instance_size              = sizeof(BDRVCURLState),
 792     .bdrv_parse_filename        = curl_parse_filename,
 793     .bdrv_file_open             = curl_open,
 794     .bdrv_close                 = curl_close,
 795     .bdrv_getlength             = curl_getlength,
 796
 797     .bdrv_aio_readv             = curl_aio_readv,
 798
 799     .bdrv_detach_aio_context    = curl_detach_aio_context,
 800     .bdrv_attach_aio_context    = curl_attach_aio_context,
 801 };
 802
 803 static BlockDriver bdrv_tftp = {
 804     .format_name                = "tftp",
 805     .protocol_name              = "tftp",
 806
 807     .instance_size              = sizeof(BDRVCURLState),
 808     .bdrv_parse_filename        = curl_parse_filename,
 809     .bdrv_file_open             = curl_open,
 810     .bdrv_close                 = curl_close,
 811     .bdrv_getlength             = curl_getlength,
 812
 813     .bdrv_aio_readv             = curl_aio_readv,
 814
 815     .bdrv_detach_aio_context    = curl_detach_aio_context,
 816     .bdrv_attach_aio_context    = curl_attach_aio_context,
 817 };
 818
 819 static void curl_block_init(void)
 820 {
 821     bdrv_register(&bdrv_http);
 822     bdrv_register(&bdrv_https);
 823     bdrv_register(&bdrv_ftp);
 824     bdrv_register(&bdrv_ftps);
 825     bdrv_register(&bdrv_tftp);
 826 }
 827
 828 block_init(curl_block_init);