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
  25 #include "qemu/osdep.h"
  26 #include "qapi/error.h"
  27 #include "qemu/error-report.h"
  28 #include "qemu/module.h"
  29 #include "qemu/option.h"
  30 #include "block/block_int.h"
  31 #include "qapi/qmp/qdict.h"
  32 #include "qapi/qmp/qstring.h"
  33 #include "crypto/secret.h"
  34 #include <curl/curl.h>
  35 #include "qemu/cutils.h"
  36 #include "trace.h"
  37
  38 // #define DEBUG_VERBOSE
  39
  40 #define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \
  41                    CURLPROTO_FTP | CURLPROTO_FTPS)
  42
  43 #define CURL_NUM_STATES 8
  44 #define CURL_NUM_ACB    8
  45 #define CURL_TIMEOUT_MAX 10000
  46
  47 #define CURL_BLOCK_OPT_URL       "url"
  48 #define CURL_BLOCK_OPT_READAHEAD "readahead"
  49 #define CURL_BLOCK_OPT_SSLVERIFY "sslverify"
  50 #define CURL_BLOCK_OPT_TIMEOUT "timeout"
  51 #define CURL_BLOCK_OPT_COOKIE    "cookie"
  52 #define CURL_BLOCK_OPT_COOKIE_SECRET "cookie-secret"
  53 #define CURL_BLOCK_OPT_USERNAME "username"
  54 #define CURL_BLOCK_OPT_PASSWORD_SECRET "password-secret"
  55 #define CURL_BLOCK_OPT_PROXY_USERNAME "proxy-username"
  56 #define CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET "proxy-password-secret"
  57
  58 #define CURL_BLOCK_OPT_READAHEAD_DEFAULT (256 * 1024)
  59 #define CURL_BLOCK_OPT_SSLVERIFY_DEFAULT true
  60 #define CURL_BLOCK_OPT_TIMEOUT_DEFAULT 5
  61
  62 struct BDRVCURLState;
  63 struct CURLState;
  64
  65 static bool libcurl_initialized;
  66
  67 typedef struct CURLAIOCB {
  68     Coroutine *co;
  69     QEMUIOVector *qiov;
  70
  71     uint64_t offset;
  72     uint64_t bytes;
  73     int ret;
  74
  75     size_t start;
  76     size_t end;
  77 } CURLAIOCB;
  78
  79 typedef struct CURLSocket {
  80     int fd;
  81     struct BDRVCURLState *s;
  82 } CURLSocket;
  83
  84 typedef struct CURLState
  85 {
  86     struct BDRVCURLState *s;
  87     CURLAIOCB *acb[CURL_NUM_ACB];
  88     CURL *curl;
  89     char *orig_buf;
  90     uint64_t buf_start;
  91     size_t buf_off;
  92     size_t buf_len;
  93     char range[128];
  94     char errmsg[CURL_ERROR_SIZE];
  95     char in_use;
  96 } CURLState;
  97
  98 typedef struct BDRVCURLState {
  99     CURLM *multi;
 100     QEMUTimer timer;
 101     uint64_t len;
 102     CURLState states[CURL_NUM_STATES];
 103     GHashTable *sockets; /* GINT_TO_POINTER(fd) -> socket */
 104     char *url;
 105     size_t readahead_size;
 106     bool sslverify;
 107     uint64_t timeout;
 108     char *cookie;
 109     bool accept_range;
 110     AioContext *aio_context;
 111     QemuMutex mutex;
 112     CoQueue free_state_waitq;
 113     char *username;
 114     char *password;
 115     char *proxyusername;
 116     char *proxypassword;
 117 } BDRVCURLState;
 118
 119 static void curl_clean_state(CURLState *s);
 120 static void curl_multi_do(void *arg);
 121
 122 static gboolean curl_drop_socket(void *key, void *value, void *opaque)
 123 {
 124     CURLSocket *socket = value;
 125     BDRVCURLState *s = socket->s;
 126
 127     aio_set_fd_handler(s->aio_context, socket->fd, false,
 128                        NULL, NULL, NULL, NULL, NULL);
 129     return true;
 130 }
 131
 132 static void curl_drop_all_sockets(GHashTable *sockets)
 133 {
 134     g_hash_table_foreach_remove(sockets, curl_drop_socket, NULL);
 135 }
 136
 137 /* Called from curl_multi_do_locked, with s->mutex held.  */
 138 static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
 139 {
 140     BDRVCURLState *s = opaque;
 141
 142     trace_curl_timer_cb(timeout_ms);
 143     if (timeout_ms == -1) {
 144         timer_del(&s->timer);
 145     } else {
 146         int64_t timeout_ns = (int64_t)timeout_ms * 1000 * 1000;
 147         timer_mod(&s->timer,
 148                   qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ns);
 149     }
 150     return 0;
 151 }
 152
 153 /* Called from curl_multi_do_locked, with s->mutex held.  */
 154 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
 155                         void *userp, void *sp)
 156 {
 157     BDRVCURLState *s;
 158     CURLState *state = NULL;
 159     CURLSocket *socket;
 160
 161     curl_easy_getinfo(curl, CURLINFO_PRIVATE, (char **)&state);
 162     s = state->s;
 163
 164     socket = g_hash_table_lookup(s->sockets, GINT_TO_POINTER(fd));
 165     if (!socket) {
 166         socket = g_new0(CURLSocket, 1);
 167         socket->fd = fd;
 168         socket->s = s;
 169         g_hash_table_insert(s->sockets, GINT_TO_POINTER(fd), socket);
 170     }
 171
 172     trace_curl_sock_cb(action, (int)fd);
 173     switch (action) {
 174         case CURL_POLL_IN:
 175             aio_set_fd_handler(s->aio_context, fd, false,
 176                                curl_multi_do, NULL, NULL, NULL, socket);
 177             break;
 178         case CURL_POLL_OUT:
 179             aio_set_fd_handler(s->aio_context, fd, false,
 180                                NULL, curl_multi_do, NULL, NULL, socket);
 181             break;
 182         case CURL_POLL_INOUT:
 183             aio_set_fd_handler(s->aio_context, fd, false,
 184                                curl_multi_do, curl_multi_do,
 185                                NULL, NULL, socket);
 186             break;
 187         case CURL_POLL_REMOVE:
 188             aio_set_fd_handler(s->aio_context, fd, false,
 189                                NULL, NULL, NULL, NULL, NULL);
 190             break;
 191     }
 192
 193     if (action == CURL_POLL_REMOVE) {
 194         g_hash_table_remove(s->sockets, GINT_TO_POINTER(fd));
 195     }
 196
 197     return 0;
 198 }
 199
 200 /* Called from curl_multi_do_locked, with s->mutex held.  */
 201 static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 202 {
 203     BDRVCURLState *s = opaque;
 204     size_t realsize = size * nmemb;
 205     const char *header = (char *)ptr;
 206     const char *end = header + realsize;
 207     const char *accept_ranges = "accept-ranges:";
 208     const char *bytes = "bytes";
 209
 210     if (realsize >= strlen(accept_ranges)
 211         && g_ascii_strncasecmp(header, accept_ranges,
 212                                strlen(accept_ranges)) == 0) {
 213
 214         char *p = strchr(header, ':') + 1;
 215
 216         /* Skip whitespace between the header name and value. */
 217         while (p < end && *p && g_ascii_isspace(*p)) {
 218             p++;
 219         }
 220
 221         if (end - p >= strlen(bytes)
 222             && strncmp(p, bytes, strlen(bytes)) == 0) {
 223
 224             /* Check that there is nothing but whitespace after the value. */
 225             p += strlen(bytes);
 226             while (p < end && *p && g_ascii_isspace(*p)) {
 227                 p++;
 228             }
 229
 230             if (p == end || !*p) {
 231                 s->accept_range = true;
 232             }
 233         }
 234     }
 235
 236     return realsize;
 237 }
 238
 239 /* Called from curl_multi_do_locked, with s->mutex held.  */
 240 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 241 {
 242     CURLState *s = ((CURLState*)opaque);
 243     size_t realsize = size * nmemb;
 244
 245     trace_curl_read_cb(realsize);
 246
 247     if (!s || !s->orig_buf) {
 248         goto read_end;
 249     }
 250
 251     if (s->buf_off >= s->buf_len) {
 252         /* buffer full, read nothing */
 253         goto read_end;
 254     }
 255     realsize = MIN(realsize, s->buf_len - s->buf_off);
 256     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 257     s->buf_off += realsize;
 258
 259 read_end:
 260     /* curl will error out if we do not return this value */
 261     return size * nmemb;
 262 }
 263
 264 /* Called with s->mutex held.  */
 265 static bool curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,
 266                           CURLAIOCB *acb)
 267 {
 268     int i;
 269     uint64_t end = start + len;
 270     uint64_t clamped_end = MIN(end, s->len);
 271     uint64_t clamped_len = clamped_end - start;
 272
 273     for (i=0; i<CURL_NUM_STATES; i++) {
 274         CURLState *state = &s->states[i];
 275         uint64_t buf_end = (state->buf_start + state->buf_off);
 276         uint64_t buf_fend = (state->buf_start + state->buf_len);
 277
 278         if (!state->orig_buf)
 279             continue;
 280         if (!state->buf_off)
 281             continue;
 282
 283         // Does the existing buffer cover our section?
 284         if ((start >= state->buf_start) &&
 285             (start <= buf_end) &&
 286             (clamped_end >= state->buf_start) &&
 287             (clamped_end <= buf_end))
 288         {
 289             char *buf = state->orig_buf + (start - state->buf_start);
 290
 291             qemu_iovec_from_buf(acb->qiov, 0, buf, clamped_len);
 292             if (clamped_len < len) {
 293                 qemu_iovec_memset(acb->qiov, clamped_len, 0, len - clamped_len);
 294             }
 295             acb->ret = 0;
 296             return true;
 297         }
 298
 299         // Wait for unfinished chunks
 300         if (state->in_use &&
 301             (start >= state->buf_start) &&
 302             (start <= buf_fend) &&
 303             (clamped_end >= state->buf_start) &&
 304             (clamped_end <= buf_fend))
 305         {
 306             int j;
 307
 308             acb->start = start - state->buf_start;
 309             acb->end = acb->start + clamped_len;
 310
 311             for (j=0; j<CURL_NUM_ACB; j++) {
 312                 if (!state->acb[j]) {
 313                     state->acb[j] = acb;
 314                     return true;
 315                 }
 316             }
 317         }
 318     }
 319
 320     return false;
 321 }
 322
 323 /* Called with s->mutex held.  */
 324 static void curl_multi_check_completion(BDRVCURLState *s)
 325 {
 326     int msgs_in_queue;
 327
 328     /* Try to find done transfers, so we can free the easy
 329      * handle again. */
 330     for (;;) {
 331         CURLMsg *msg;
 332         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 333
 334         /* Quit when there are no more completions */
 335         if (!msg)
 336             break;
 337
 338         if (msg->msg == CURLMSG_DONE) {
 339             int i;
 340             CURLState *state = NULL;
 341             bool error = msg->data.result != CURLE_OK;
 342
 343             curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE,
 344                               (char **)&state);
 345
 346             if (error) {
 347                 static int errcount = 100;
 348
 349                 /* Don't lose the original error message from curl, since
 350                  * it contains extra data.
 351                  */
 352                 if (errcount > 0) {
 353                     error_report("curl: %s", state->errmsg);
 354                     if (--errcount == 0) {
 355                         error_report("curl: further errors suppressed");
 356                     }
 357                 }
 358             }
 359
 360             for (i = 0; i < CURL_NUM_ACB; i++) {
 361                 CURLAIOCB *acb = state->acb[i];
 362
 363                 if (acb == NULL) {
 364                     continue;
 365                 }
 366
 367                 if (!error) {
 368                     /* Assert that we have read all data */
 369                     assert(state->buf_off >= acb->end);
 370
 371                     qemu_iovec_from_buf(acb->qiov, 0,
 372                                         state->orig_buf + acb->start,
 373                                         acb->end - acb->start);
 374
 375                     if (acb->end - acb->start < acb->bytes) {
 376                         size_t offset = acb->end - acb->start;
 377                         qemu_iovec_memset(acb->qiov, offset, 0,
 378                                           acb->bytes - offset);
 379                     }
 380                 }
 381
 382                 acb->ret = error ? -EIO : 0;
 383                 state->acb[i] = NULL;
 384                 qemu_mutex_unlock(&s->mutex);
 385                 aio_co_wake(acb->co);
 386                 qemu_mutex_lock(&s->mutex);
 387             }
 388
 389             curl_clean_state(state);
 390             break;
 391         }
 392     }
 393 }
 394
 395 /* Called with s->mutex held.  */
 396 static void curl_multi_do_locked(CURLSocket *socket)
 397 {
 398     BDRVCURLState *s = socket->s;
 399     int running;
 400     int r;
 401
 402     if (!s->multi) {
 403         return;
 404     }
 405
 406     do {
 407         r = curl_multi_socket_action(s->multi, socket->fd, 0, &running);
 408     } while (r == CURLM_CALL_MULTI_PERFORM);
 409 }
 410
 411 static void curl_multi_do(void *arg)
 412 {
 413     CURLSocket *socket = arg;
 414     BDRVCURLState *s = socket->s;
 415
 416     qemu_mutex_lock(&s->mutex);
 417     curl_multi_do_locked(socket);
 418     curl_multi_check_completion(s);
 419     qemu_mutex_unlock(&s->mutex);
 420 }
 421
 422 static void curl_multi_timeout_do(void *arg)
 423 {
 424     BDRVCURLState *s = (BDRVCURLState *)arg;
 425     int running;
 426
 427     if (!s->multi) {
 428         return;
 429     }
 430
 431     qemu_mutex_lock(&s->mutex);
 432     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 433
 434     curl_multi_check_completion(s);
 435     qemu_mutex_unlock(&s->mutex);
 436 }
 437
 438 /* Called with s->mutex held.  */
 439 static CURLState *curl_find_state(BDRVCURLState *s)
 440 {
 441     CURLState *state = NULL;
 442     int i;
 443
 444     for (i = 0; i < CURL_NUM_STATES; i++) {
 445         if (!s->states[i].in_use) {
 446             state = &s->states[i];
 447             state->in_use = 1;
 448             break;
 449         }
 450     }
 451     return state;
 452 }
 453
 454 static int curl_init_state(BDRVCURLState *s, CURLState *state)
 455 {
 456     if (!state->curl) {
 457         state->curl = curl_easy_init();
 458         if (!state->curl) {
 459             return -EIO;
 460         }
 461         curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 462         curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYPEER,
 463                          (long) s->sslverify);
 464         curl_easy_setopt(state->curl, CURLOPT_SSL_VERIFYHOST,
 465                          s->sslverify ? 2L : 0L);
 466         if (s->cookie) {
 467             curl_easy_setopt(state->curl, CURLOPT_COOKIE, s->cookie);
 468         }
 469         curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, (long)s->timeout);
 470         curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION,
 471                          (void *)curl_read_cb);
 472         curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 473         curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 474         curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 475         curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 476         curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 477         curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 478         curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
 479
 480         if (s->username) {
 481             curl_easy_setopt(state->curl, CURLOPT_USERNAME, s->username);
 482         }
 483         if (s->password) {
 484             curl_easy_setopt(state->curl, CURLOPT_PASSWORD, s->password);
 485         }
 486         if (s->proxyusername) {
 487             curl_easy_setopt(state->curl,
 488                              CURLOPT_PROXYUSERNAME, s->proxyusername);
 489         }
 490         if (s->proxypassword) {
 491             curl_easy_setopt(state->curl,
 492                              CURLOPT_PROXYPASSWORD, s->proxypassword);
 493         }
 494
 495         /* Restrict supported protocols to avoid security issues in the more
 496          * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see
 497          * CVE-2013-0249.
 498          *
 499          * Restricting protocols is only supported from 7.19.4 upwards.
 500          */
 501 #if LIBCURL_VERSION_NUM >= 0x071304
 502         curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);
 503         curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);
 504 #endif
 505
 506 #ifdef DEBUG_VERBOSE
 507         curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 508 #endif
 509     }
 510
 511     state->s = s;
 512
 513     return 0;
 514 }
 515
 516 /* Called with s->mutex held.  */
 517 static void curl_clean_state(CURLState *s)
 518 {
 519     int j;
 520     for (j = 0; j < CURL_NUM_ACB; j++) {
 521         assert(!s->acb[j]);
 522     }
 523
 524     if (s->s->multi)
 525         curl_multi_remove_handle(s->s->multi, s->curl);
 526
 527     s->in_use = 0;
 528
 529     qemu_co_enter_next(&s->s->free_state_waitq, &s->s->mutex);
 530 }
 531
 532 static void curl_parse_filename(const char *filename, QDict *options,
 533                                 Error **errp)
 534 {
 535     qdict_put_str(options, CURL_BLOCK_OPT_URL, filename);
 536 }
 537
 538 static void curl_detach_aio_context(BlockDriverState *bs)
 539 {
 540     BDRVCURLState *s = bs->opaque;
 541     int i;
 542
 543     WITH_QEMU_LOCK_GUARD(&s->mutex) {
 544         curl_drop_all_sockets(s->sockets);
 545         for (i = 0; i < CURL_NUM_STATES; i++) {
 546             if (s->states[i].in_use) {
 547                 curl_clean_state(&s->states[i]);
 548             }
 549             if (s->states[i].curl) {
 550                 curl_easy_cleanup(s->states[i].curl);
 551                 s->states[i].curl = NULL;
 552             }
 553             g_free(s->states[i].orig_buf);
 554             s->states[i].orig_buf = NULL;
 555         }
 556         if (s->multi) {
 557             curl_multi_cleanup(s->multi);
 558             s->multi = NULL;
 559         }
 560     }
 561
 562     timer_del(&s->timer);
 563 }
 564
 565 static void curl_attach_aio_context(BlockDriverState *bs,
 566                                     AioContext *new_context)
 567 {
 568     BDRVCURLState *s = bs->opaque;
 569
 570     aio_timer_init(new_context, &s->timer,
 571                    QEMU_CLOCK_REALTIME, SCALE_NS,
 572                    curl_multi_timeout_do, s);
 573
 574     assert(!s->multi);
 575     s->multi = curl_multi_init();
 576     s->aio_context = new_context;
 577     curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
 578     curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
 579     curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
 580 }
 581
 582 static QemuOptsList runtime_opts = {
 583     .name = "curl",
 584     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 585     .desc = {
 586         {
 587             .name = CURL_BLOCK_OPT_URL,
 588             .type = QEMU_OPT_STRING,
 589             .help = "URL to open",
 590         },
 591         {
 592             .name = CURL_BLOCK_OPT_READAHEAD,
 593             .type = QEMU_OPT_SIZE,
 594             .help = "Readahead size",
 595         },
 596         {
 597             .name = CURL_BLOCK_OPT_SSLVERIFY,
 598             .type = QEMU_OPT_BOOL,
 599             .help = "Verify SSL certificate"
 600         },
 601         {
 602             .name = CURL_BLOCK_OPT_TIMEOUT,
 603             .type = QEMU_OPT_NUMBER,
 604             .help = "Curl timeout"
 605         },
 606         {
 607             .name = CURL_BLOCK_OPT_COOKIE,
 608             .type = QEMU_OPT_STRING,
 609             .help = "Pass the cookie or list of cookies with each request"
 610         },
 611         {
 612             .name = CURL_BLOCK_OPT_COOKIE_SECRET,
 613             .type = QEMU_OPT_STRING,
 614             .help = "ID of secret used as cookie passed with each request"
 615         },
 616         {
 617             .name = CURL_BLOCK_OPT_USERNAME,
 618             .type = QEMU_OPT_STRING,
 619             .help = "Username for HTTP auth"
 620         },
 621         {
 622             .name = CURL_BLOCK_OPT_PASSWORD_SECRET,
 623             .type = QEMU_OPT_STRING,
 624             .help = "ID of secret used as password for HTTP auth",
 625         },
 626         {
 627             .name = CURL_BLOCK_OPT_PROXY_USERNAME,
 628             .type = QEMU_OPT_STRING,
 629             .help = "Username for HTTP proxy auth"
 630         },
 631         {
 632             .name = CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET,
 633             .type = QEMU_OPT_STRING,
 634             .help = "ID of secret used as password for HTTP proxy auth",
 635         },
 636         { /* end of list */ }
 637     },
 638 };
 639
 640
 641 static int curl_open(BlockDriverState *bs, QDict *options, int flags,
 642                      Error **errp)
 643 {
 644     BDRVCURLState *s = bs->opaque;
 645     CURLState *state = NULL;
 646     QemuOpts *opts;
 647     const char *file;
 648     const char *cookie;
 649     const char *cookie_secret;
 650     double d;
 651     const char *secretid;
 652     const char *protocol_delimiter;
 653     int ret;
 654
 655     ret = bdrv_apply_auto_read_only(bs, "curl driver does not support writes",
 656                                     errp);
 657     if (ret < 0) {
 658         return ret;
 659     }
 660
 661     if (!libcurl_initialized) {
 662         ret = curl_global_init(CURL_GLOBAL_ALL);
 663         if (ret) {
 664             error_setg(errp, "libcurl initialization failed with %d", ret);
 665             return -EIO;
 666         }
 667         libcurl_initialized = true;
 668     }
 669
 670     qemu_mutex_init(&s->mutex);
 671     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 672     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
 673         goto out_noclean;
 674     }
 675
 676     s->readahead_size = qemu_opt_get_size(opts, CURL_BLOCK_OPT_READAHEAD,
 677                                           CURL_BLOCK_OPT_READAHEAD_DEFAULT);
 678     if ((s->readahead_size & 0x1ff) != 0) {
 679         error_setg(errp, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512",
 680                    s->readahead_size);
 681         goto out_noclean;
 682     }
 683
 684     s->timeout = qemu_opt_get_number(opts, CURL_BLOCK_OPT_TIMEOUT,
 685                                      CURL_BLOCK_OPT_TIMEOUT_DEFAULT);
 686     if (s->timeout > CURL_TIMEOUT_MAX) {
 687         error_setg(errp, "timeout parameter is too large or negative");
 688         goto out_noclean;
 689     }
 690
 691     s->sslverify = qemu_opt_get_bool(opts, CURL_BLOCK_OPT_SSLVERIFY,
 692                                      CURL_BLOCK_OPT_SSLVERIFY_DEFAULT);
 693
 694     cookie = qemu_opt_get(opts, CURL_BLOCK_OPT_COOKIE);
 695     cookie_secret = qemu_opt_get(opts, CURL_BLOCK_OPT_COOKIE_SECRET);
 696
 697     if (cookie && cookie_secret) {
 698         error_setg(errp,
 699                    "curl driver cannot handle both cookie and cookie secret");
 700         goto out_noclean;
 701     }
 702
 703     if (cookie_secret) {
 704         s->cookie = qcrypto_secret_lookup_as_utf8(cookie_secret, errp);
 705         if (!s->cookie) {
 706             goto out_noclean;
 707         }
 708     } else {
 709         s->cookie = g_strdup(cookie);
 710     }
 711
 712     file = qemu_opt_get(opts, CURL_BLOCK_OPT_URL);
 713     if (file == NULL) {
 714         error_setg(errp, "curl block driver requires an 'url' option");
 715         goto out_noclean;
 716     }
 717
 718     if (!strstart(file, bs->drv->protocol_name, &protocol_delimiter) ||
 719         !strstart(protocol_delimiter, "://", NULL))
 720     {
 721         error_setg(errp, "%s curl driver cannot handle the URL '%s' (does not "
 722                    "start with '%s://')", bs->drv->protocol_name, file,
 723                    bs->drv->protocol_name);
 724         goto out_noclean;
 725     }
 726
 727     s->username = g_strdup(qemu_opt_get(opts, CURL_BLOCK_OPT_USERNAME));
 728     secretid = qemu_opt_get(opts, CURL_BLOCK_OPT_PASSWORD_SECRET);
 729
 730     if (secretid) {
 731         s->password = qcrypto_secret_lookup_as_utf8(secretid, errp);
 732         if (!s->password) {
 733             goto out_noclean;
 734         }
 735     }
 736
 737     s->proxyusername = g_strdup(
 738         qemu_opt_get(opts, CURL_BLOCK_OPT_PROXY_USERNAME));
 739     secretid = qemu_opt_get(opts, CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET);
 740     if (secretid) {
 741         s->proxypassword = qcrypto_secret_lookup_as_utf8(secretid, errp);
 742         if (!s->proxypassword) {
 743             goto out_noclean;
 744         }
 745     }
 746
 747     trace_curl_open(file);
 748     qemu_co_queue_init(&s->free_state_waitq);
 749     s->aio_context = bdrv_get_aio_context(bs);
 750     s->url = g_strdup(file);
 751     s->sockets = g_hash_table_new_full(NULL, NULL, NULL, g_free);
 752     qemu_mutex_lock(&s->mutex);
 753     state = curl_find_state(s);
 754     qemu_mutex_unlock(&s->mutex);
 755     if (!state) {
 756         goto out_noclean;
 757     }
 758
 759     // Get file size
 760
 761     if (curl_init_state(s, state) < 0) {
 762         goto out;
 763     }
 764
 765     s->accept_range = false;
 766     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 767     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
 768                      curl_header_cb);
 769     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
 770     if (curl_easy_perform(state->curl))
 771         goto out;
 772     if (curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d)) {
 773         goto out;
 774     }
 775     /* Prior CURL 7.19.4 return value of 0 could mean that the file size is not
 776      * know or the size is zero. From 7.19.4 CURL returns -1 if size is not
 777      * known and zero if it is really zero-length file. */
 778 #if LIBCURL_VERSION_NUM >= 0x071304
 779     if (d < 0) {
 780         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
 781                 "Server didn't report file size.");
 782         goto out;
 783     }
 784 #else
 785     if (d <= 0) {
 786         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
 787                 "Unknown file size or zero-length file.");
 788         goto out;
 789     }
 790 #endif
 791
 792     s->len = d;
 793
 794     if ((!strncasecmp(s->url, "http://", strlen("http://"))
 795         || !strncasecmp(s->url, "https://", strlen("https://")))
 796         && !s->accept_range) {
 797         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
 798                 "Server does not support 'range' (byte ranges).");
 799         goto out;
 800     }
 801     trace_curl_open_size(s->len);
 802
 803     qemu_mutex_lock(&s->mutex);
 804     curl_clean_state(state);
 805     qemu_mutex_unlock(&s->mutex);
 806     curl_easy_cleanup(state->curl);
 807     state->curl = NULL;
 808
 809     curl_attach_aio_context(bs, bdrv_get_aio_context(bs));
 810
 811     qemu_opts_del(opts);
 812     return 0;
 813
 814 out:
 815     error_setg(errp, "CURL: Error opening file: %s", state->errmsg);
 816     curl_easy_cleanup(state->curl);
 817     state->curl = NULL;
 818 out_noclean:
 819     qemu_mutex_destroy(&s->mutex);
 820     g_free(s->cookie);
 821     g_free(s->url);
 822     g_free(s->username);
 823     g_free(s->proxyusername);
 824     g_free(s->proxypassword);
 825     curl_drop_all_sockets(s->sockets);
 826     g_hash_table_destroy(s->sockets);
 827     qemu_opts_del(opts);
 828     return -EINVAL;
 829 }
 830
 831 static void curl_setup_preadv(BlockDriverState *bs, CURLAIOCB *acb)
 832 {
 833     CURLState *state;
 834     int running;
 835
 836     BDRVCURLState *s = bs->opaque;
 837
 838     uint64_t start = acb->offset;
 839     uint64_t end;
 840
 841     qemu_mutex_lock(&s->mutex);
 842
 843     // In case we have the requested data already (e.g. read-ahead),
 844     // we can just call the callback and be done.
 845     if (curl_find_buf(s, start, acb->bytes, acb)) {
 846         goto out;
 847     }
 848
 849     // No cache found, so let's start a new request
 850     for (;;) {
 851         state = curl_find_state(s);
 852         if (state) {
 853             break;
 854         }
 855         qemu_co_queue_wait(&s->free_state_waitq, &s->mutex);
 856     }
 857
 858     if (curl_init_state(s, state) < 0) {
 859         curl_clean_state(state);
 860         acb->ret = -EIO;
 861         goto out;
 862     }
 863
 864     acb->start = 0;
 865     acb->end = MIN(acb->bytes, s->len - start);
 866
 867     state->buf_off = 0;
 868     g_free(state->orig_buf);
 869     state->buf_start = start;
 870     state->buf_len = MIN(acb->end + s->readahead_size, s->len - start);
 871     end = start + state->buf_len - 1;
 872     state->orig_buf = g_try_malloc(state->buf_len);
 873     if (state->buf_len && state->orig_buf == NULL) {
 874         curl_clean_state(state);
 875         acb->ret = -ENOMEM;
 876         goto out;
 877     }
 878     state->acb[0] = acb;
 879
 880     snprintf(state->range, 127, "%" PRIu64 "-%" PRIu64, start, end);
 881     trace_curl_setup_preadv(acb->bytes, start, state->range);
 882     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 883
 884     if (curl_multi_add_handle(s->multi, state->curl) != CURLM_OK) {
 885         state->acb[0] = NULL;
 886         acb->ret = -EIO;
 887
 888         curl_clean_state(state);
 889         goto out;
 890     }
 891
 892     /* Tell curl it needs to kick things off */
 893     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 894
 895 out:
 896     qemu_mutex_unlock(&s->mutex);
 897 }
 898
 899 static int coroutine_fn curl_co_preadv(BlockDriverState *bs,
 900         int64_t offset, int64_t bytes, QEMUIOVector *qiov,
 901         BdrvRequestFlags flags)
 902 {
 903     CURLAIOCB acb = {
 904         .co = qemu_coroutine_self(),
 905         .ret = -EINPROGRESS,
 906         .qiov = qiov,
 907         .offset = offset,
 908         .bytes = bytes
 909     };
 910
 911     curl_setup_preadv(bs, &acb);
 912     while (acb.ret == -EINPROGRESS) {
 913         qemu_coroutine_yield();
 914     }
 915     return acb.ret;
 916 }
 917
 918 static void curl_close(BlockDriverState *bs)
 919 {
 920     BDRVCURLState *s = bs->opaque;
 921
 922     trace_curl_close();
 923     curl_detach_aio_context(bs);
 924     qemu_mutex_destroy(&s->mutex);
 925
 926     g_hash_table_destroy(s->sockets);
 927     g_free(s->cookie);
 928     g_free(s->url);
 929     g_free(s->username);
 930     g_free(s->proxyusername);
 931     g_free(s->proxypassword);
 932 }
 933
 934 static int64_t curl_getlength(BlockDriverState *bs)
 935 {
 936     BDRVCURLState *s = bs->opaque;
 937     return s->len;
 938 }
 939
 940 static void curl_refresh_filename(BlockDriverState *bs)
 941 {
 942     BDRVCURLState *s = bs->opaque;
 943
 944     /* "readahead" and "timeout" do not change the guest-visible data,
 945      * so ignore them */
 946     if (s->sslverify != CURL_BLOCK_OPT_SSLVERIFY_DEFAULT ||
 947         s->cookie || s->username || s->password || s->proxyusername ||
 948         s->proxypassword)
 949     {
 950         return;
 951     }
 952
 953     pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), s->url);
 954 }
 955
 956
 957 static const char *const curl_strong_runtime_opts[] = {
 958     CURL_BLOCK_OPT_URL,
 959     CURL_BLOCK_OPT_SSLVERIFY,
 960     CURL_BLOCK_OPT_COOKIE,
 961     CURL_BLOCK_OPT_COOKIE_SECRET,
 962     CURL_BLOCK_OPT_USERNAME,
 963     CURL_BLOCK_OPT_PASSWORD_SECRET,
 964     CURL_BLOCK_OPT_PROXY_USERNAME,
 965     CURL_BLOCK_OPT_PROXY_PASSWORD_SECRET,
 966
 967     NULL
 968 };
 969
 970 static BlockDriver bdrv_http = {
 971     .format_name                = "http",
 972     .protocol_name              = "http",
 973
 974     .instance_size              = sizeof(BDRVCURLState),
 975     .bdrv_parse_filename        = curl_parse_filename,
 976     .bdrv_file_open             = curl_open,
 977     .bdrv_close                 = curl_close,
 978     .bdrv_getlength             = curl_getlength,
 979
 980     .bdrv_co_preadv             = curl_co_preadv,
 981
 982     .bdrv_detach_aio_context    = curl_detach_aio_context,
 983     .bdrv_attach_aio_context    = curl_attach_aio_context,
 984
 985     .bdrv_refresh_filename      = curl_refresh_filename,
 986     .strong_runtime_opts        = curl_strong_runtime_opts,
 987 };
 988
 989 static BlockDriver bdrv_https = {
 990     .format_name                = "https",
 991     .protocol_name              = "https",
 992
 993     .instance_size              = sizeof(BDRVCURLState),
 994     .bdrv_parse_filename        = curl_parse_filename,
 995     .bdrv_file_open             = curl_open,
 996     .bdrv_close                 = curl_close,
 997     .bdrv_getlength             = curl_getlength,
 998
 999     .bdrv_co_preadv             = curl_co_preadv,
1000
1001     .bdrv_detach_aio_context    = curl_detach_aio_context,
1002     .bdrv_attach_aio_context    = curl_attach_aio_context,
1003
1004     .bdrv_refresh_filename      = curl_refresh_filename,
1005     .strong_runtime_opts        = curl_strong_runtime_opts,
1006 };
1007
1008 static BlockDriver bdrv_ftp = {
1009     .format_name                = "ftp",
1010     .protocol_name              = "ftp",
1011
1012     .instance_size              = sizeof(BDRVCURLState),
1013     .bdrv_parse_filename        = curl_parse_filename,
1014     .bdrv_file_open             = curl_open,
1015     .bdrv_close                 = curl_close,
1016     .bdrv_getlength             = curl_getlength,
1017
1018     .bdrv_co_preadv             = curl_co_preadv,
1019
1020     .bdrv_detach_aio_context    = curl_detach_aio_context,
1021     .bdrv_attach_aio_context    = curl_attach_aio_context,
1022
1023     .bdrv_refresh_filename      = curl_refresh_filename,
1024     .strong_runtime_opts        = curl_strong_runtime_opts,
1025 };
1026
1027 static BlockDriver bdrv_ftps = {
1028     .format_name                = "ftps",
1029     .protocol_name              = "ftps",
1030
1031     .instance_size              = sizeof(BDRVCURLState),
1032     .bdrv_parse_filename        = curl_parse_filename,
1033     .bdrv_file_open             = curl_open,
1034     .bdrv_close                 = curl_close,
1035     .bdrv_getlength             = curl_getlength,
1036
1037     .bdrv_co_preadv             = curl_co_preadv,
1038
1039     .bdrv_detach_aio_context    = curl_detach_aio_context,
1040     .bdrv_attach_aio_context    = curl_attach_aio_context,
1041
1042     .bdrv_refresh_filename      = curl_refresh_filename,
1043     .strong_runtime_opts        = curl_strong_runtime_opts,
1044 };
1045
1046 static void curl_block_init(void)
1047 {
1048     bdrv_register(&bdrv_http);
1049     bdrv_register(&bdrv_https);
1050     bdrv_register(&bdrv_ftp);
1051     bdrv_register(&bdrv_ftps);
1052 }
1053
1054 block_init(curl_block_init);