xref: /openbmc/qemu/block/curl.c (revision 0399a381)
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 #if LIBCURL_VERSION_NUM >= 0x071000
38 /* The multi interface timer callback was introduced in 7.16.0 */
39 #define NEED_CURL_TIMER_CALLBACK
40 #endif
41 
42 #define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \
43                    CURLPROTO_FTP | CURLPROTO_FTPS | \
44                    CURLPROTO_TFTP)
45 
46 #define CURL_NUM_STATES 8
47 #define CURL_NUM_ACB    8
48 #define SECTOR_SIZE     512
49 #define READ_AHEAD_SIZE (256 * 1024)
50 
51 #define FIND_RET_NONE   0
52 #define FIND_RET_OK     1
53 #define FIND_RET_WAIT   2
54 
55 struct BDRVCURLState;
56 
57 typedef struct CURLAIOCB {
58     BlockDriverAIOCB common;
59     QEMUBH *bh;
60     QEMUIOVector *qiov;
61 
62     int64_t sector_num;
63     int nb_sectors;
64 
65     size_t start;
66     size_t end;
67 } CURLAIOCB;
68 
69 typedef struct CURLState
70 {
71     struct BDRVCURLState *s;
72     CURLAIOCB *acb[CURL_NUM_ACB];
73     CURL *curl;
74     char *orig_buf;
75     size_t buf_start;
76     size_t buf_off;
77     size_t buf_len;
78     char range[128];
79     char errmsg[CURL_ERROR_SIZE];
80     char in_use;
81 } CURLState;
82 
83 typedef struct BDRVCURLState {
84     CURLM *multi;
85     QEMUTimer timer;
86     size_t len;
87     CURLState states[CURL_NUM_STATES];
88     char *url;
89     size_t readahead_size;
90     bool accept_range;
91 } BDRVCURLState;
92 
93 static void curl_clean_state(CURLState *s);
94 static void curl_multi_do(void *arg);
95 
96 #ifdef NEED_CURL_TIMER_CALLBACK
97 static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
98 {
99     BDRVCURLState *s = opaque;
100 
101     DPRINTF("CURL: timer callback timeout_ms %ld\n", timeout_ms);
102     if (timeout_ms == -1) {
103         timer_del(&s->timer);
104     } else {
105         int64_t timeout_ns = (int64_t)timeout_ms * 1000 * 1000;
106         timer_mod(&s->timer,
107                   qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ns);
108     }
109     return 0;
110 }
111 #endif
112 
113 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
114                         void *s, void *sp)
115 {
116     DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
117     switch (action) {
118         case CURL_POLL_IN:
119             qemu_aio_set_fd_handler(fd, curl_multi_do, NULL, s);
120             break;
121         case CURL_POLL_OUT:
122             qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, s);
123             break;
124         case CURL_POLL_INOUT:
125             qemu_aio_set_fd_handler(fd, curl_multi_do, curl_multi_do, s);
126             break;
127         case CURL_POLL_REMOVE:
128             qemu_aio_set_fd_handler(fd, NULL, NULL, NULL);
129             break;
130     }
131 
132     return 0;
133 }
134 
135 static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
136 {
137     BDRVCURLState *s = opaque;
138     size_t realsize = size * nmemb;
139     const char *accept_line = "Accept-Ranges: bytes";
140 
141     if (realsize >= strlen(accept_line)
142         && strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
143         s->accept_range = true;
144     }
145 
146     return realsize;
147 }
148 
149 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
150 {
151     CURLState *s = ((CURLState*)opaque);
152     size_t realsize = size * nmemb;
153     int i;
154 
155     DPRINTF("CURL: Just reading %zd bytes\n", realsize);
156 
157     if (!s || !s->orig_buf)
158         goto read_end;
159 
160     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
161     s->buf_off += realsize;
162 
163     for(i=0; i<CURL_NUM_ACB; i++) {
164         CURLAIOCB *acb = s->acb[i];
165 
166         if (!acb)
167             continue;
168 
169         if ((s->buf_off >= acb->end)) {
170             qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start,
171                                 acb->end - acb->start);
172             acb->common.cb(acb->common.opaque, 0);
173             qemu_aio_release(acb);
174             s->acb[i] = NULL;
175         }
176     }
177 
178 read_end:
179     return realsize;
180 }
181 
182 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
183                          CURLAIOCB *acb)
184 {
185     int i;
186     size_t end = start + len;
187 
188     for (i=0; i<CURL_NUM_STATES; i++) {
189         CURLState *state = &s->states[i];
190         size_t buf_end = (state->buf_start + state->buf_off);
191         size_t buf_fend = (state->buf_start + state->buf_len);
192 
193         if (!state->orig_buf)
194             continue;
195         if (!state->buf_off)
196             continue;
197 
198         // Does the existing buffer cover our section?
199         if ((start >= state->buf_start) &&
200             (start <= buf_end) &&
201             (end >= state->buf_start) &&
202             (end <= buf_end))
203         {
204             char *buf = state->orig_buf + (start - state->buf_start);
205 
206             qemu_iovec_from_buf(acb->qiov, 0, buf, len);
207             acb->common.cb(acb->common.opaque, 0);
208 
209             return FIND_RET_OK;
210         }
211 
212         // Wait for unfinished chunks
213         if ((start >= state->buf_start) &&
214             (start <= buf_fend) &&
215             (end >= state->buf_start) &&
216             (end <= buf_fend))
217         {
218             int j;
219 
220             acb->start = start - state->buf_start;
221             acb->end = acb->start + len;
222 
223             for (j=0; j<CURL_NUM_ACB; j++) {
224                 if (!state->acb[j]) {
225                     state->acb[j] = acb;
226                     return FIND_RET_WAIT;
227                 }
228             }
229         }
230     }
231 
232     return FIND_RET_NONE;
233 }
234 
235 static void curl_multi_read(BDRVCURLState *s)
236 {
237     int msgs_in_queue;
238 
239     /* Try to find done transfers, so we can free the easy
240      * handle again. */
241     do {
242         CURLMsg *msg;
243         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
244 
245         if (!msg)
246             break;
247         if (msg->msg == CURLMSG_NONE)
248             break;
249 
250         switch (msg->msg) {
251             case CURLMSG_DONE:
252             {
253                 CURLState *state = NULL;
254                 curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, (char**)&state);
255 
256                 /* ACBs for successful messages get completed in curl_read_cb */
257                 if (msg->data.result != CURLE_OK) {
258                     int i;
259                     for (i = 0; i < CURL_NUM_ACB; i++) {
260                         CURLAIOCB *acb = state->acb[i];
261 
262                         if (acb == NULL) {
263                             continue;
264                         }
265 
266                         acb->common.cb(acb->common.opaque, -EIO);
267                         qemu_aio_release(acb);
268                         state->acb[i] = NULL;
269                     }
270                 }
271 
272                 curl_clean_state(state);
273                 break;
274             }
275             default:
276                 msgs_in_queue = 0;
277                 break;
278         }
279     } while(msgs_in_queue);
280 }
281 
282 static void curl_multi_do(void *arg)
283 {
284     BDRVCURLState *s = (BDRVCURLState *)arg;
285     int running;
286     int r;
287 
288     if (!s->multi) {
289         return;
290     }
291 
292     do {
293         r = curl_multi_socket_all(s->multi, &running);
294     } while(r == CURLM_CALL_MULTI_PERFORM);
295 
296     curl_multi_read(s);
297 }
298 
299 static void curl_multi_timeout_do(void *arg)
300 {
301 #ifdef NEED_CURL_TIMER_CALLBACK
302     BDRVCURLState *s = (BDRVCURLState *)arg;
303     int running;
304 
305     if (!s->multi) {
306         return;
307     }
308 
309     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
310 
311     curl_multi_read(s);
312 #else
313     abort();
314 #endif
315 }
316 
317 static CURLState *curl_init_state(BDRVCURLState *s)
318 {
319     CURLState *state = NULL;
320     int i, j;
321 
322     do {
323         for (i=0; i<CURL_NUM_STATES; i++) {
324             for (j=0; j<CURL_NUM_ACB; j++)
325                 if (s->states[i].acb[j])
326                     continue;
327             if (s->states[i].in_use)
328                 continue;
329 
330             state = &s->states[i];
331             state->in_use = 1;
332             break;
333         }
334         if (!state) {
335             g_usleep(100);
336             curl_multi_do(s);
337         }
338     } while(!state);
339 
340     if (state->curl)
341         goto has_curl;
342 
343     state->curl = curl_easy_init();
344     if (!state->curl)
345         return NULL;
346     curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
347     curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);
348     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);
349     curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
350     curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
351     curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
352     curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
353     curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
354     curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
355     curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
356 
357     /* Restrict supported protocols to avoid security issues in the more
358      * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see
359      * CVE-2013-0249.
360      *
361      * Restricting protocols is only supported from 7.19.4 upwards.
362      */
363 #if LIBCURL_VERSION_NUM >= 0x071304
364     curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);
365     curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);
366 #endif
367 
368 #ifdef DEBUG_VERBOSE
369     curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
370 #endif
371 
372 has_curl:
373 
374     state->s = s;
375 
376     return state;
377 }
378 
379 static void curl_clean_state(CURLState *s)
380 {
381     if (s->s->multi)
382         curl_multi_remove_handle(s->s->multi, s->curl);
383     s->in_use = 0;
384 }
385 
386 static void curl_parse_filename(const char *filename, QDict *options,
387                                 Error **errp)
388 {
389 
390     #define RA_OPTSTR ":readahead="
391     char *file;
392     char *ra;
393     const char *ra_val;
394     int parse_state = 0;
395 
396     file = g_strdup(filename);
397 
398     /* Parse a trailing ":readahead=#:" param, if present. */
399     ra = file + strlen(file) - 1;
400     while (ra >= file) {
401         if (parse_state == 0) {
402             if (*ra == ':') {
403                 parse_state++;
404             } else {
405                 break;
406             }
407         } else if (parse_state == 1) {
408             if (*ra > '9' || *ra < '0') {
409                 char *opt_start = ra - strlen(RA_OPTSTR) + 1;
410                 if (opt_start > file &&
411                     strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {
412                     ra_val = ra + 1;
413                     ra -= strlen(RA_OPTSTR) - 1;
414                     *ra = '\0';
415                     qdict_put(options, "readahead", qstring_from_str(ra_val));
416                 }
417                 break;
418             }
419         }
420         ra--;
421     }
422 
423     qdict_put(options, "url", qstring_from_str(file));
424 
425     g_free(file);
426 }
427 
428 static QemuOptsList runtime_opts = {
429     .name = "curl",
430     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
431     .desc = {
432         {
433             .name = "url",
434             .type = QEMU_OPT_STRING,
435             .help = "URL to open",
436         },
437         {
438             .name = "readahead",
439             .type = QEMU_OPT_SIZE,
440             .help = "Readahead size",
441         },
442         { /* end of list */ }
443     },
444 };
445 
446 static int curl_open(BlockDriverState *bs, QDict *options, int flags,
447                      Error **errp)
448 {
449     BDRVCURLState *s = bs->opaque;
450     CURLState *state = NULL;
451     QemuOpts *opts;
452     Error *local_err = NULL;
453     const char *file;
454     double d;
455 
456     static int inited = 0;
457 
458     if (flags & BDRV_O_RDWR) {
459         error_setg(errp, "curl block device does not support writes");
460         return -EROFS;
461     }
462 
463     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
464     qemu_opts_absorb_qdict(opts, options, &local_err);
465     if (local_err) {
466         error_propagate(errp, local_err);
467         goto out_noclean;
468     }
469 
470     s->readahead_size = qemu_opt_get_size(opts, "readahead", READ_AHEAD_SIZE);
471     if ((s->readahead_size & 0x1ff) != 0) {
472         error_setg(errp, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512",
473                    s->readahead_size);
474         goto out_noclean;
475     }
476 
477     file = qemu_opt_get(opts, "url");
478     if (file == NULL) {
479         error_setg(errp, "curl block driver requires an 'url' option");
480         goto out_noclean;
481     }
482 
483     if (!inited) {
484         curl_global_init(CURL_GLOBAL_ALL);
485         inited = 1;
486     }
487 
488     DPRINTF("CURL: Opening %s\n", file);
489     s->url = g_strdup(file);
490     state = curl_init_state(s);
491     if (!state)
492         goto out_noclean;
493 
494     // Get file size
495 
496     s->accept_range = false;
497     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
498     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
499                      curl_header_cb);
500     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
501     if (curl_easy_perform(state->curl))
502         goto out;
503     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
504     if (d)
505         s->len = (size_t)d;
506     else if(!s->len)
507         goto out;
508     if ((!strncasecmp(s->url, "http://", strlen("http://"))
509         || !strncasecmp(s->url, "https://", strlen("https://")))
510         && !s->accept_range) {
511         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
512                 "Server does not support 'range' (byte ranges).");
513         goto out;
514     }
515     DPRINTF("CURL: Size = %zd\n", s->len);
516 
517     curl_clean_state(state);
518     curl_easy_cleanup(state->curl);
519     state->curl = NULL;
520 
521     aio_timer_init(bdrv_get_aio_context(bs), &s->timer,
522                    QEMU_CLOCK_REALTIME, SCALE_NS,
523                    curl_multi_timeout_do, s);
524 
525     // Now we know the file exists and its size, so let's
526     // initialize the multi interface!
527 
528     s->multi = curl_multi_init();
529     curl_multi_setopt(s->multi, CURLMOPT_SOCKETDATA, s);
530     curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
531 #ifdef NEED_CURL_TIMER_CALLBACK
532     curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
533     curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
534 #endif
535     curl_multi_do(s);
536 
537     qemu_opts_del(opts);
538     return 0;
539 
540 out:
541     fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);
542     curl_easy_cleanup(state->curl);
543     state->curl = NULL;
544 out_noclean:
545     g_free(s->url);
546     qemu_opts_del(opts);
547     return -EINVAL;
548 }
549 
550 static void curl_aio_cancel(BlockDriverAIOCB *blockacb)
551 {
552     // Do we have to implement canceling? Seems to work without...
553 }
554 
555 static const AIOCBInfo curl_aiocb_info = {
556     .aiocb_size         = sizeof(CURLAIOCB),
557     .cancel             = curl_aio_cancel,
558 };
559 
560 
561 static void curl_readv_bh_cb(void *p)
562 {
563     CURLState *state;
564 
565     CURLAIOCB *acb = p;
566     BDRVCURLState *s = acb->common.bs->opaque;
567 
568     qemu_bh_delete(acb->bh);
569     acb->bh = NULL;
570 
571     size_t start = acb->sector_num * SECTOR_SIZE;
572     size_t end;
573 
574     // In case we have the requested data already (e.g. read-ahead),
575     // we can just call the callback and be done.
576     switch (curl_find_buf(s, start, acb->nb_sectors * SECTOR_SIZE, acb)) {
577         case FIND_RET_OK:
578             qemu_aio_release(acb);
579             // fall through
580         case FIND_RET_WAIT:
581             return;
582         default:
583             break;
584     }
585 
586     // No cache found, so let's start a new request
587     state = curl_init_state(s);
588     if (!state) {
589         acb->common.cb(acb->common.opaque, -EIO);
590         qemu_aio_release(acb);
591         return;
592     }
593 
594     acb->start = 0;
595     acb->end = (acb->nb_sectors * SECTOR_SIZE);
596 
597     state->buf_off = 0;
598     if (state->orig_buf)
599         g_free(state->orig_buf);
600     state->buf_start = start;
601     state->buf_len = acb->end + s->readahead_size;
602     end = MIN(start + state->buf_len, s->len) - 1;
603     state->orig_buf = g_malloc(state->buf_len);
604     state->acb[0] = acb;
605 
606     snprintf(state->range, 127, "%zd-%zd", start, end);
607     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
608             (acb->nb_sectors * SECTOR_SIZE), start, state->range);
609     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
610 
611     curl_multi_add_handle(s->multi, state->curl);
612     curl_multi_do(s);
613 
614 }
615 
616 static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
617         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
618         BlockDriverCompletionFunc *cb, void *opaque)
619 {
620     CURLAIOCB *acb;
621 
622     acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);
623 
624     acb->qiov = qiov;
625     acb->sector_num = sector_num;
626     acb->nb_sectors = nb_sectors;
627 
628     acb->bh = qemu_bh_new(curl_readv_bh_cb, acb);
629     qemu_bh_schedule(acb->bh);
630     return &acb->common;
631 }
632 
633 static void curl_close(BlockDriverState *bs)
634 {
635     BDRVCURLState *s = bs->opaque;
636     int i;
637 
638     DPRINTF("CURL: Close\n");
639     for (i=0; i<CURL_NUM_STATES; i++) {
640         if (s->states[i].in_use)
641             curl_clean_state(&s->states[i]);
642         if (s->states[i].curl) {
643             curl_easy_cleanup(s->states[i].curl);
644             s->states[i].curl = NULL;
645         }
646         if (s->states[i].orig_buf) {
647             g_free(s->states[i].orig_buf);
648             s->states[i].orig_buf = NULL;
649         }
650     }
651     if (s->multi)
652         curl_multi_cleanup(s->multi);
653 
654     timer_del(&s->timer);
655 
656     g_free(s->url);
657 }
658 
659 static int64_t curl_getlength(BlockDriverState *bs)
660 {
661     BDRVCURLState *s = bs->opaque;
662     return s->len;
663 }
664 
665 static BlockDriver bdrv_http = {
666     .format_name            = "http",
667     .protocol_name          = "http",
668 
669     .instance_size          = sizeof(BDRVCURLState),
670     .bdrv_parse_filename    = curl_parse_filename,
671     .bdrv_file_open         = curl_open,
672     .bdrv_close             = curl_close,
673     .bdrv_getlength         = curl_getlength,
674 
675     .bdrv_aio_readv         = curl_aio_readv,
676 };
677 
678 static BlockDriver bdrv_https = {
679     .format_name            = "https",
680     .protocol_name          = "https",
681 
682     .instance_size          = sizeof(BDRVCURLState),
683     .bdrv_parse_filename    = curl_parse_filename,
684     .bdrv_file_open         = curl_open,
685     .bdrv_close             = curl_close,
686     .bdrv_getlength         = curl_getlength,
687 
688     .bdrv_aio_readv         = curl_aio_readv,
689 };
690 
691 static BlockDriver bdrv_ftp = {
692     .format_name            = "ftp",
693     .protocol_name          = "ftp",
694 
695     .instance_size          = sizeof(BDRVCURLState),
696     .bdrv_parse_filename    = curl_parse_filename,
697     .bdrv_file_open         = curl_open,
698     .bdrv_close             = curl_close,
699     .bdrv_getlength         = curl_getlength,
700 
701     .bdrv_aio_readv         = curl_aio_readv,
702 };
703 
704 static BlockDriver bdrv_ftps = {
705     .format_name            = "ftps",
706     .protocol_name          = "ftps",
707 
708     .instance_size          = sizeof(BDRVCURLState),
709     .bdrv_parse_filename    = curl_parse_filename,
710     .bdrv_file_open         = curl_open,
711     .bdrv_close             = curl_close,
712     .bdrv_getlength         = curl_getlength,
713 
714     .bdrv_aio_readv         = curl_aio_readv,
715 };
716 
717 static BlockDriver bdrv_tftp = {
718     .format_name            = "tftp",
719     .protocol_name          = "tftp",
720 
721     .instance_size          = sizeof(BDRVCURLState),
722     .bdrv_parse_filename    = curl_parse_filename,
723     .bdrv_file_open         = curl_open,
724     .bdrv_close             = curl_close,
725     .bdrv_getlength         = curl_getlength,
726 
727     .bdrv_aio_readv         = curl_aio_readv,
728 };
729 
730 static void curl_block_init(void)
731 {
732     bdrv_register(&bdrv_http);
733     bdrv_register(&bdrv_https);
734     bdrv_register(&bdrv_ftp);
735     bdrv_register(&bdrv_ftps);
736     bdrv_register(&bdrv_tftp);
737 }
738 
739 block_init(curl_block_init);
740