xref: /openbmc/qemu/block/curl.c (revision 63785678)
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 "qapi/error.h"
26 #include "qemu-common.h"
27 #include "qemu/error-report.h"
28 #include "block/block_int.h"
29 #include "qapi/qmp/qbool.h"
30 #include "qapi/qmp/qstring.h"
31 #include "crypto/secret.h"
32 #include <curl/curl.h>
33 #include "qemu/cutils.h"
34 
35 // #define DEBUG_CURL
36 // #define DEBUG_VERBOSE
37 
38 #ifdef DEBUG_CURL
39 #define DPRINTF(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)
40 #else
41 #define DPRINTF(fmt, ...) do { } while (0)
42 #endif
43 
44 #if LIBCURL_VERSION_NUM >= 0x071000
45 /* The multi interface timer callback was introduced in 7.16.0 */
46 #define NEED_CURL_TIMER_CALLBACK
47 #define HAVE_SOCKET_ACTION
48 #endif
49 
50 #ifndef HAVE_SOCKET_ACTION
51 /* If curl_multi_socket_action isn't available, define it statically here in
52  * terms of curl_multi_socket. Note that ev_bitmask will be ignored, which is
53  * less efficient but still safe. */
54 static CURLMcode __curl_multi_socket_action(CURLM *multi_handle,
55                                             curl_socket_t sockfd,
56                                             int ev_bitmask,
57                                             int *running_handles)
58 {
59     return curl_multi_socket(multi_handle, sockfd, running_handles);
60 }
61 #define curl_multi_socket_action __curl_multi_socket_action
62 #endif
63 
64 #define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \
65                    CURLPROTO_FTP | CURLPROTO_FTPS | \
66                    CURLPROTO_TFTP)
67 
68 #define CURL_NUM_STATES 8
69 #define CURL_NUM_ACB    8
70 #define SECTOR_SIZE     512
71 #define READ_AHEAD_DEFAULT (256 * 1024)
72 #define CURL_TIMEOUT_DEFAULT 5
73 #define CURL_TIMEOUT_MAX 10000
74 
75 #define FIND_RET_NONE   0
76 #define FIND_RET_OK     1
77 #define FIND_RET_WAIT   2
78 
79 #define CURL_BLOCK_OPT_URL       "url"
80 #define CURL_BLOCK_OPT_READAHEAD "readahead"
81 #define CURL_BLOCK_OPT_SSLVERIFY "sslverify"
82 #define CURL_BLOCK_OPT_TIMEOUT "timeout"
83 #define CURL_BLOCK_OPT_COOKIE    "cookie"
84 #define CURL_BLOCK_OPT_USERNAME "username"
85 #define CURL_BLOCK_OPT_PASSWORD_SECRET "password-secret"
86 #define CURL_BLOCK_OPT_PROXY_USERNAME "proxy-username"
87 #define CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET "proxy-password-secret"
88 
89 struct BDRVCURLState;
90 
91 typedef struct CURLAIOCB {
92     BlockAIOCB common;
93     QEMUBH *bh;
94     QEMUIOVector *qiov;
95 
96     int64_t sector_num;
97     int nb_sectors;
98 
99     size_t start;
100     size_t end;
101 } CURLAIOCB;
102 
103 typedef struct CURLState
104 {
105     struct BDRVCURLState *s;
106     CURLAIOCB *acb[CURL_NUM_ACB];
107     CURL *curl;
108     curl_socket_t sock_fd;
109     char *orig_buf;
110     size_t buf_start;
111     size_t buf_off;
112     size_t buf_len;
113     char range[128];
114     char errmsg[CURL_ERROR_SIZE];
115     char in_use;
116 } CURLState;
117 
118 typedef struct BDRVCURLState {
119     CURLM *multi;
120     QEMUTimer timer;
121     size_t len;
122     CURLState states[CURL_NUM_STATES];
123     char *url;
124     size_t readahead_size;
125     bool sslverify;
126     uint64_t timeout;
127     char *cookie;
128     bool accept_range;
129     AioContext *aio_context;
130     char *username;
131     char *password;
132     char *proxyusername;
133     char *proxypassword;
134 } BDRVCURLState;
135 
136 static void curl_clean_state(CURLState *s);
137 static void curl_multi_do(void *arg);
138 static void curl_multi_read(void *arg);
139 
140 #ifdef NEED_CURL_TIMER_CALLBACK
141 static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
142 {
143     BDRVCURLState *s = opaque;
144 
145     DPRINTF("CURL: timer callback timeout_ms %ld\n", timeout_ms);
146     if (timeout_ms == -1) {
147         timer_del(&s->timer);
148     } else {
149         int64_t timeout_ns = (int64_t)timeout_ms * 1000 * 1000;
150         timer_mod(&s->timer,
151                   qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ns);
152     }
153     return 0;
154 }
155 #endif
156 
157 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
158                         void *userp, void *sp)
159 {
160     BDRVCURLState *s;
161     CURLState *state = NULL;
162     curl_easy_getinfo(curl, CURLINFO_PRIVATE, (char **)&state);
163     state->sock_fd = fd;
164     s = state->s;
165 
166     DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
167     switch (action) {
168         case CURL_POLL_IN:
169             aio_set_fd_handler(s->aio_context, fd, false,
170                                curl_multi_read, NULL, state);
171             break;
172         case CURL_POLL_OUT:
173             aio_set_fd_handler(s->aio_context, fd, false,
174                                NULL, curl_multi_do, state);
175             break;
176         case CURL_POLL_INOUT:
177             aio_set_fd_handler(s->aio_context, fd, false,
178                                curl_multi_read, curl_multi_do, state);
179             break;
180         case CURL_POLL_REMOVE:
181             aio_set_fd_handler(s->aio_context, fd, false,
182                                NULL, NULL, NULL);
183             break;
184     }
185 
186     return 0;
187 }
188 
189 static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
190 {
191     BDRVCURLState *s = opaque;
192     size_t realsize = size * nmemb;
193     const char *accept_line = "Accept-Ranges: bytes";
194 
195     if (realsize >= strlen(accept_line)
196         && strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
197         s->accept_range = true;
198     }
199 
200     return realsize;
201 }
202 
203 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
204 {
205     CURLState *s = ((CURLState*)opaque);
206     size_t realsize = size * nmemb;
207     int i;
208 
209     DPRINTF("CURL: Just reading %zd bytes\n", realsize);
210 
211     if (!s || !s->orig_buf)
212         return 0;
213 
214     if (s->buf_off >= s->buf_len) {
215         /* buffer full, read nothing */
216         return 0;
217     }
218     realsize = MIN(realsize, s->buf_len - s->buf_off);
219     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
220     s->buf_off += realsize;
221 
222     for(i=0; i<CURL_NUM_ACB; i++) {
223         CURLAIOCB *acb = s->acb[i];
224 
225         if (!acb)
226             continue;
227 
228         if ((s->buf_off >= acb->end)) {
229             qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start,
230                                 acb->end - acb->start);
231             acb->common.cb(acb->common.opaque, 0);
232             qemu_aio_unref(acb);
233             s->acb[i] = NULL;
234         }
235     }
236 
237     return realsize;
238 }
239 
240 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
241                          CURLAIOCB *acb)
242 {
243     int i;
244     size_t end = start + len;
245 
246     for (i=0; i<CURL_NUM_STATES; i++) {
247         CURLState *state = &s->states[i];
248         size_t buf_end = (state->buf_start + state->buf_off);
249         size_t buf_fend = (state->buf_start + state->buf_len);
250 
251         if (!state->orig_buf)
252             continue;
253         if (!state->buf_off)
254             continue;
255 
256         // Does the existing buffer cover our section?
257         if ((start >= state->buf_start) &&
258             (start <= buf_end) &&
259             (end >= state->buf_start) &&
260             (end <= buf_end))
261         {
262             char *buf = state->orig_buf + (start - state->buf_start);
263 
264             qemu_iovec_from_buf(acb->qiov, 0, buf, len);
265             acb->common.cb(acb->common.opaque, 0);
266 
267             return FIND_RET_OK;
268         }
269 
270         // Wait for unfinished chunks
271         if (state->in_use &&
272             (start >= state->buf_start) &&
273             (start <= buf_fend) &&
274             (end >= state->buf_start) &&
275             (end <= buf_fend))
276         {
277             int j;
278 
279             acb->start = start - state->buf_start;
280             acb->end = acb->start + len;
281 
282             for (j=0; j<CURL_NUM_ACB; j++) {
283                 if (!state->acb[j]) {
284                     state->acb[j] = acb;
285                     return FIND_RET_WAIT;
286                 }
287             }
288         }
289     }
290 
291     return FIND_RET_NONE;
292 }
293 
294 static void curl_multi_check_completion(BDRVCURLState *s)
295 {
296     int msgs_in_queue;
297 
298     /* Try to find done transfers, so we can free the easy
299      * handle again. */
300     for (;;) {
301         CURLMsg *msg;
302         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
303 
304         /* Quit when there are no more completions */
305         if (!msg)
306             break;
307 
308         if (msg->msg == CURLMSG_DONE) {
309             CURLState *state = NULL;
310             curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE,
311                               (char **)&state);
312 
313             /* ACBs for successful messages get completed in curl_read_cb */
314             if (msg->data.result != CURLE_OK) {
315                 int i;
316                 static int errcount = 100;
317 
318                 /* Don't lose the original error message from curl, since
319                  * it contains extra data.
320                  */
321                 if (errcount > 0) {
322                     error_report("curl: %s", state->errmsg);
323                     if (--errcount == 0) {
324                         error_report("curl: further errors suppressed");
325                     }
326                 }
327 
328                 for (i = 0; i < CURL_NUM_ACB; i++) {
329                     CURLAIOCB *acb = state->acb[i];
330 
331                     if (acb == NULL) {
332                         continue;
333                     }
334 
335                     acb->common.cb(acb->common.opaque, -EPROTO);
336                     qemu_aio_unref(acb);
337                     state->acb[i] = NULL;
338                 }
339             }
340 
341             curl_clean_state(state);
342             break;
343         }
344     }
345 }
346 
347 static void curl_multi_do(void *arg)
348 {
349     CURLState *s = (CURLState *)arg;
350     int running;
351     int r;
352 
353     if (!s->s->multi) {
354         return;
355     }
356 
357     do {
358         r = curl_multi_socket_action(s->s->multi, s->sock_fd, 0, &running);
359     } while(r == CURLM_CALL_MULTI_PERFORM);
360 
361 }
362 
363 static void curl_multi_read(void *arg)
364 {
365     CURLState *s = (CURLState *)arg;
366 
367     curl_multi_do(arg);
368     curl_multi_check_completion(s->s);
369 }
370 
371 static void curl_multi_timeout_do(void *arg)
372 {
373 #ifdef NEED_CURL_TIMER_CALLBACK
374     BDRVCURLState *s = (BDRVCURLState *)arg;
375     int running;
376 
377     if (!s->multi) {
378         return;
379     }
380 
381     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
382 
383     curl_multi_check_completion(s);
384 #else
385     abort();
386 #endif
387 }
388 
389 static CURLState *curl_init_state(BlockDriverState *bs, BDRVCURLState *s)
390 {
391     CURLState *state = NULL;
392     int i, j;
393 
394     do {
395         for (i=0; i<CURL_NUM_STATES; i++) {
396             for (j=0; j<CURL_NUM_ACB; j++)
397                 if (s->states[i].acb[j])
398                     continue;
399             if (s->states[i].in_use)
400                 continue;
401 
402             state = &s->states[i];
403             state->in_use = 1;
404             break;
405         }
406         if (!state) {
407             aio_poll(bdrv_get_aio_context(bs), true);
408         }
409     } while(!state);
410 
411     if (!state->curl) {
412         state->curl = curl_easy_init();
413         if (!state->curl) {
414             return NULL;
415         }
416         curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
417         curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYPEER,
418                          (long) s->sslverify);
419         if (s->cookie) {
420             curl_easy_setopt(state->curl, CURLOPT_COOKIE, s->cookie);
421         }
422         curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, (long)s->timeout);
423         curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION,
424                          (void *)curl_read_cb);
425         curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
426         curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
427         curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
428         curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
429         curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
430         curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
431         curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
432 
433         if (s->username) {
434             curl_easy_setopt(state->curl, CURLOPT_USERNAME, s->username);
435         }
436         if (s->password) {
437             curl_easy_setopt(state->curl, CURLOPT_PASSWORD, s->password);
438         }
439         if (s->proxyusername) {
440             curl_easy_setopt(state->curl,
441                              CURLOPT_PROXYUSERNAME, s->proxyusername);
442         }
443         if (s->proxypassword) {
444             curl_easy_setopt(state->curl,
445                              CURLOPT_PROXYPASSWORD, s->proxypassword);
446         }
447 
448         /* Restrict supported protocols to avoid security issues in the more
449          * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see
450          * CVE-2013-0249.
451          *
452          * Restricting protocols is only supported from 7.19.4 upwards.
453          */
454 #if LIBCURL_VERSION_NUM >= 0x071304
455         curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);
456         curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);
457 #endif
458 
459 #ifdef DEBUG_VERBOSE
460         curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
461 #endif
462     }
463 
464     state->s = s;
465 
466     return state;
467 }
468 
469 static void curl_clean_state(CURLState *s)
470 {
471     if (s->s->multi)
472         curl_multi_remove_handle(s->s->multi, s->curl);
473     s->in_use = 0;
474 }
475 
476 static void curl_parse_filename(const char *filename, QDict *options,
477                                 Error **errp)
478 {
479     qdict_put(options, CURL_BLOCK_OPT_URL, qstring_from_str(filename));
480 }
481 
482 static void curl_detach_aio_context(BlockDriverState *bs)
483 {
484     BDRVCURLState *s = bs->opaque;
485     int i;
486 
487     for (i = 0; i < CURL_NUM_STATES; i++) {
488         if (s->states[i].in_use) {
489             curl_clean_state(&s->states[i]);
490         }
491         if (s->states[i].curl) {
492             curl_easy_cleanup(s->states[i].curl);
493             s->states[i].curl = NULL;
494         }
495         g_free(s->states[i].orig_buf);
496         s->states[i].orig_buf = NULL;
497     }
498     if (s->multi) {
499         curl_multi_cleanup(s->multi);
500         s->multi = NULL;
501     }
502 
503     timer_del(&s->timer);
504 }
505 
506 static void curl_attach_aio_context(BlockDriverState *bs,
507                                     AioContext *new_context)
508 {
509     BDRVCURLState *s = bs->opaque;
510 
511     aio_timer_init(new_context, &s->timer,
512                    QEMU_CLOCK_REALTIME, SCALE_NS,
513                    curl_multi_timeout_do, s);
514 
515     assert(!s->multi);
516     s->multi = curl_multi_init();
517     s->aio_context = new_context;
518     curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
519 #ifdef NEED_CURL_TIMER_CALLBACK
520     curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
521     curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
522 #endif
523 }
524 
525 static QemuOptsList runtime_opts = {
526     .name = "curl",
527     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
528     .desc = {
529         {
530             .name = CURL_BLOCK_OPT_URL,
531             .type = QEMU_OPT_STRING,
532             .help = "URL to open",
533         },
534         {
535             .name = CURL_BLOCK_OPT_READAHEAD,
536             .type = QEMU_OPT_SIZE,
537             .help = "Readahead size",
538         },
539         {
540             .name = CURL_BLOCK_OPT_SSLVERIFY,
541             .type = QEMU_OPT_BOOL,
542             .help = "Verify SSL certificate"
543         },
544         {
545             .name = CURL_BLOCK_OPT_TIMEOUT,
546             .type = QEMU_OPT_NUMBER,
547             .help = "Curl timeout"
548         },
549         {
550             .name = CURL_BLOCK_OPT_COOKIE,
551             .type = QEMU_OPT_STRING,
552             .help = "Pass the cookie or list of cookies with each request"
553         },
554         {
555             .name = CURL_BLOCK_OPT_USERNAME,
556             .type = QEMU_OPT_STRING,
557             .help = "Username for HTTP auth"
558         },
559         {
560             .name = CURL_BLOCK_OPT_PASSWORD_SECRET,
561             .type = QEMU_OPT_STRING,
562             .help = "ID of secret used as password for HTTP auth",
563         },
564         {
565             .name = CURL_BLOCK_OPT_PROXY_USERNAME,
566             .type = QEMU_OPT_STRING,
567             .help = "Username for HTTP proxy auth"
568         },
569         {
570             .name = CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET,
571             .type = QEMU_OPT_STRING,
572             .help = "ID of secret used as password for HTTP proxy auth",
573         },
574         { /* end of list */ }
575     },
576 };
577 
578 
579 static int curl_open(BlockDriverState *bs, QDict *options, int flags,
580                      Error **errp)
581 {
582     BDRVCURLState *s = bs->opaque;
583     CURLState *state = NULL;
584     QemuOpts *opts;
585     Error *local_err = NULL;
586     const char *file;
587     const char *cookie;
588     double d;
589     const char *secretid;
590 
591     static int inited = 0;
592 
593     if (flags & BDRV_O_RDWR) {
594         error_setg(errp, "curl block device does not support writes");
595         return -EROFS;
596     }
597 
598     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
599     qemu_opts_absorb_qdict(opts, options, &local_err);
600     if (local_err) {
601         error_propagate(errp, local_err);
602         goto out_noclean;
603     }
604 
605     s->readahead_size = qemu_opt_get_size(opts, CURL_BLOCK_OPT_READAHEAD,
606                                           READ_AHEAD_DEFAULT);
607     if ((s->readahead_size & 0x1ff) != 0) {
608         error_setg(errp, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512",
609                    s->readahead_size);
610         goto out_noclean;
611     }
612 
613     s->timeout = qemu_opt_get_number(opts, CURL_BLOCK_OPT_TIMEOUT,
614                                      CURL_TIMEOUT_DEFAULT);
615     if (s->timeout > CURL_TIMEOUT_MAX) {
616         error_setg(errp, "timeout parameter is too large or negative");
617         goto out_noclean;
618     }
619 
620     s->sslverify = qemu_opt_get_bool(opts, CURL_BLOCK_OPT_SSLVERIFY, true);
621 
622     cookie = qemu_opt_get(opts, CURL_BLOCK_OPT_COOKIE);
623     s->cookie = g_strdup(cookie);
624 
625     file = qemu_opt_get(opts, CURL_BLOCK_OPT_URL);
626     if (file == NULL) {
627         error_setg(errp, "curl block driver requires an 'url' option");
628         goto out_noclean;
629     }
630 
631     s->username = g_strdup(qemu_opt_get(opts, CURL_BLOCK_OPT_USERNAME));
632     secretid = qemu_opt_get(opts, CURL_BLOCK_OPT_PASSWORD_SECRET);
633 
634     if (secretid) {
635         s->password = qcrypto_secret_lookup_as_utf8(secretid, errp);
636         if (!s->password) {
637             goto out_noclean;
638         }
639     }
640 
641     s->proxyusername = g_strdup(
642         qemu_opt_get(opts, CURL_BLOCK_OPT_PROXY_USERNAME));
643     secretid = qemu_opt_get(opts, CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET);
644     if (secretid) {
645         s->proxypassword = qcrypto_secret_lookup_as_utf8(secretid, errp);
646         if (!s->proxypassword) {
647             goto out_noclean;
648         }
649     }
650 
651     if (!inited) {
652         curl_global_init(CURL_GLOBAL_ALL);
653         inited = 1;
654     }
655 
656     DPRINTF("CURL: Opening %s\n", file);
657     s->aio_context = bdrv_get_aio_context(bs);
658     s->url = g_strdup(file);
659     state = curl_init_state(bs, s);
660     if (!state)
661         goto out_noclean;
662 
663     // Get file size
664 
665     s->accept_range = false;
666     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
667     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
668                      curl_header_cb);
669     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
670     if (curl_easy_perform(state->curl))
671         goto out;
672     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
673     if (d)
674         s->len = (size_t)d;
675     else if(!s->len)
676         goto out;
677     if ((!strncasecmp(s->url, "http://", strlen("http://"))
678         || !strncasecmp(s->url, "https://", strlen("https://")))
679         && !s->accept_range) {
680         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
681                 "Server does not support 'range' (byte ranges).");
682         goto out;
683     }
684     DPRINTF("CURL: Size = %zd\n", s->len);
685 
686     curl_clean_state(state);
687     curl_easy_cleanup(state->curl);
688     state->curl = NULL;
689 
690     curl_attach_aio_context(bs, bdrv_get_aio_context(bs));
691 
692     qemu_opts_del(opts);
693     return 0;
694 
695 out:
696     error_setg(errp, "CURL: Error opening file: %s", state->errmsg);
697     curl_easy_cleanup(state->curl);
698     state->curl = NULL;
699 out_noclean:
700     g_free(s->cookie);
701     g_free(s->url);
702     qemu_opts_del(opts);
703     return -EINVAL;
704 }
705 
706 static const AIOCBInfo curl_aiocb_info = {
707     .aiocb_size         = sizeof(CURLAIOCB),
708 };
709 
710 
711 static void curl_readv_bh_cb(void *p)
712 {
713     CURLState *state;
714     int running;
715 
716     CURLAIOCB *acb = p;
717     BDRVCURLState *s = acb->common.bs->opaque;
718 
719     qemu_bh_delete(acb->bh);
720     acb->bh = NULL;
721 
722     size_t start = acb->sector_num * SECTOR_SIZE;
723     size_t end;
724 
725     // In case we have the requested data already (e.g. read-ahead),
726     // we can just call the callback and be done.
727     switch (curl_find_buf(s, start, acb->nb_sectors * SECTOR_SIZE, acb)) {
728         case FIND_RET_OK:
729             qemu_aio_unref(acb);
730             // fall through
731         case FIND_RET_WAIT:
732             return;
733         default:
734             break;
735     }
736 
737     // No cache found, so let's start a new request
738     state = curl_init_state(acb->common.bs, s);
739     if (!state) {
740         acb->common.cb(acb->common.opaque, -EIO);
741         qemu_aio_unref(acb);
742         return;
743     }
744 
745     acb->start = 0;
746     acb->end = (acb->nb_sectors * SECTOR_SIZE);
747 
748     state->buf_off = 0;
749     g_free(state->orig_buf);
750     state->buf_start = start;
751     state->buf_len = acb->end + s->readahead_size;
752     end = MIN(start + state->buf_len, s->len) - 1;
753     state->orig_buf = g_try_malloc(state->buf_len);
754     if (state->buf_len && state->orig_buf == NULL) {
755         curl_clean_state(state);
756         acb->common.cb(acb->common.opaque, -ENOMEM);
757         qemu_aio_unref(acb);
758         return;
759     }
760     state->acb[0] = acb;
761 
762     snprintf(state->range, 127, "%zd-%zd", start, end);
763     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
764             (acb->nb_sectors * SECTOR_SIZE), start, state->range);
765     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
766 
767     curl_multi_add_handle(s->multi, state->curl);
768 
769     /* Tell curl it needs to kick things off */
770     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
771 }
772 
773 static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
774         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
775         BlockCompletionFunc *cb, void *opaque)
776 {
777     CURLAIOCB *acb;
778 
779     acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);
780 
781     acb->qiov = qiov;
782     acb->sector_num = sector_num;
783     acb->nb_sectors = nb_sectors;
784 
785     acb->bh = aio_bh_new(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
786     qemu_bh_schedule(acb->bh);
787     return &acb->common;
788 }
789 
790 static void curl_close(BlockDriverState *bs)
791 {
792     BDRVCURLState *s = bs->opaque;
793 
794     DPRINTF("CURL: Close\n");
795     curl_detach_aio_context(bs);
796 
797     g_free(s->cookie);
798     g_free(s->url);
799 }
800 
801 static int64_t curl_getlength(BlockDriverState *bs)
802 {
803     BDRVCURLState *s = bs->opaque;
804     return s->len;
805 }
806 
807 static BlockDriver bdrv_http = {
808     .format_name                = "http",
809     .protocol_name              = "http",
810 
811     .instance_size              = sizeof(BDRVCURLState),
812     .bdrv_parse_filename        = curl_parse_filename,
813     .bdrv_file_open             = curl_open,
814     .bdrv_close                 = curl_close,
815     .bdrv_getlength             = curl_getlength,
816 
817     .bdrv_aio_readv             = curl_aio_readv,
818 
819     .bdrv_detach_aio_context    = curl_detach_aio_context,
820     .bdrv_attach_aio_context    = curl_attach_aio_context,
821 };
822 
823 static BlockDriver bdrv_https = {
824     .format_name                = "https",
825     .protocol_name              = "https",
826 
827     .instance_size              = sizeof(BDRVCURLState),
828     .bdrv_parse_filename        = curl_parse_filename,
829     .bdrv_file_open             = curl_open,
830     .bdrv_close                 = curl_close,
831     .bdrv_getlength             = curl_getlength,
832 
833     .bdrv_aio_readv             = curl_aio_readv,
834 
835     .bdrv_detach_aio_context    = curl_detach_aio_context,
836     .bdrv_attach_aio_context    = curl_attach_aio_context,
837 };
838 
839 static BlockDriver bdrv_ftp = {
840     .format_name                = "ftp",
841     .protocol_name              = "ftp",
842 
843     .instance_size              = sizeof(BDRVCURLState),
844     .bdrv_parse_filename        = curl_parse_filename,
845     .bdrv_file_open             = curl_open,
846     .bdrv_close                 = curl_close,
847     .bdrv_getlength             = curl_getlength,
848 
849     .bdrv_aio_readv             = curl_aio_readv,
850 
851     .bdrv_detach_aio_context    = curl_detach_aio_context,
852     .bdrv_attach_aio_context    = curl_attach_aio_context,
853 };
854 
855 static BlockDriver bdrv_ftps = {
856     .format_name                = "ftps",
857     .protocol_name              = "ftps",
858 
859     .instance_size              = sizeof(BDRVCURLState),
860     .bdrv_parse_filename        = curl_parse_filename,
861     .bdrv_file_open             = curl_open,
862     .bdrv_close                 = curl_close,
863     .bdrv_getlength             = curl_getlength,
864 
865     .bdrv_aio_readv             = curl_aio_readv,
866 
867     .bdrv_detach_aio_context    = curl_detach_aio_context,
868     .bdrv_attach_aio_context    = curl_attach_aio_context,
869 };
870 
871 static BlockDriver bdrv_tftp = {
872     .format_name                = "tftp",
873     .protocol_name              = "tftp",
874 
875     .instance_size              = sizeof(BDRVCURLState),
876     .bdrv_parse_filename        = curl_parse_filename,
877     .bdrv_file_open             = curl_open,
878     .bdrv_close                 = curl_close,
879     .bdrv_getlength             = curl_getlength,
880 
881     .bdrv_aio_readv             = curl_aio_readv,
882 
883     .bdrv_detach_aio_context    = curl_detach_aio_context,
884     .bdrv_attach_aio_context    = curl_attach_aio_context,
885 };
886 
887 static void curl_block_init(void)
888 {
889     bdrv_register(&bdrv_http);
890     bdrv_register(&bdrv_https);
891     bdrv_register(&bdrv_ftp);
892     bdrv_register(&bdrv_ftps);
893     bdrv_register(&bdrv_tftp);
894 }
895 
896 block_init(curl_block_init);
897