src/httpfetch.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "socket.h" // for select()
  21 #include "porting.h" // for sleep_ms(), get_sysinfo()
  22 #include "httpfetch.h"
  23 #include <iostream>
  24 #include <sstream>
  25 #include <list>
  26 #include <map>
  27 #include <errno.h>
  28 #include "jthread/jevent.h"
  29 #include "config.h"
  30 #include "exceptions.h"
  31 #include "debug.h"
  32 #include "log.h"
  33 #include "util/container.h"
  34 #include "util/thread.h"
  35 #include "version.h"
  36 #include "main.h"
  37 #include "settings.h"
  38
  39 JMutex g_httpfetch_mutex;
  40 std::map<unsigned long, std::list<HTTPFetchResult> > g_httpfetch_results;
  41
  42 HTTPFetchRequest::HTTPFetchRequest()
  43 {
  44         url = "";
  45         caller = HTTPFETCH_DISCARD;
  46         request_id = 0;
  47         timeout = g_settings->getS32("curl_timeout");
  48         connect_timeout = timeout;
  49         multipart = false;
  50
  51         useragent = std::string("Minetest/") + minetest_version_hash + " (" + porting::get_sysinfo() + ")";
  52 }
  53
  54
  55 static void httpfetch_deliver_result(const HTTPFetchResult &fetch_result)
  56 {
  57         unsigned long caller = fetch_result.caller;
  58         if (caller != HTTPFETCH_DISCARD) {
  59                 JMutexAutoLock lock(g_httpfetch_mutex);
  60                 g_httpfetch_results[caller].push_back(fetch_result);
  61         }
  62 }
  63
  64 static void httpfetch_request_clear(unsigned long caller);
  65
  66 unsigned long httpfetch_caller_alloc()
  67 {
  68         JMutexAutoLock lock(g_httpfetch_mutex);
  69
  70         // Check each caller ID except HTTPFETCH_DISCARD
  71         const unsigned long discard = HTTPFETCH_DISCARD;
  72         for (unsigned long caller = discard + 1; caller != discard; ++caller) {
  73                 std::map<unsigned long, std::list<HTTPFetchResult> >::iterator
  74                         it = g_httpfetch_results.find(caller);
  75                 if (it == g_httpfetch_results.end()) {
  76                         verbosestream<<"httpfetch_caller_alloc: allocating "
  77                                         <<caller<<std::endl;
  78                         // Access element to create it
  79                         g_httpfetch_results[caller];
  80                         return caller;
  81                 }
  82         }
  83
  84         assert("httpfetch_caller_alloc: ran out of caller IDs" == 0);
  85         return discard;
  86 }
  87
  88 void httpfetch_caller_free(unsigned long caller)
  89 {
  90         verbosestream<<"httpfetch_caller_free: freeing "
  91                         <<caller<<std::endl;
  92
  93         httpfetch_request_clear(caller);
  94         if (caller != HTTPFETCH_DISCARD) {
  95                 JMutexAutoLock lock(g_httpfetch_mutex);
  96                 g_httpfetch_results.erase(caller);
  97         }
  98 }
  99
 100 bool httpfetch_async_get(unsigned long caller, HTTPFetchResult &fetch_result)
 101 {
 102         JMutexAutoLock lock(g_httpfetch_mutex);
 103
 104         // Check that caller exists
 105         std::map<unsigned long, std::list<HTTPFetchResult> >::iterator
 106                 it = g_httpfetch_results.find(caller);
 107         if (it == g_httpfetch_results.end())
 108                 return false;
 109
 110         // Check that result queue is nonempty
 111         std::list<HTTPFetchResult> &caller_results = it->second;
 112         if (caller_results.empty())
 113                 return false;
 114
 115         // Pop first result
 116         fetch_result = caller_results.front();
 117         caller_results.pop_front();
 118         return true;
 119 }
 120
 121 #if USE_CURL
 122 #include <curl/curl.h>
 123
 124 /*
 125         USE_CURL is on: use cURL based httpfetch implementation
 126 */
 127
 128 static size_t httpfetch_writefunction(
 129                 char *ptr, size_t size, size_t nmemb, void *userdata)
 130 {
 131         std::ostringstream *stream = (std::ostringstream*)userdata;
 132         size_t count = size * nmemb;
 133         stream->write(ptr, count);
 134         return count;
 135 }
 136
 137 static size_t httpfetch_discardfunction(
 138                 char *ptr, size_t size, size_t nmemb, void *userdata)
 139 {
 140         return size * nmemb;
 141 }
 142
 143 class CurlHandlePool
 144 {
 145         std::list<CURL*> handles;
 146
 147 public:
 148         CurlHandlePool() {}
 149         ~CurlHandlePool()
 150         {
 151                 for (std::list<CURL*>::iterator it = handles.begin();
 152                                 it != handles.end(); ++it) {
 153                         curl_easy_cleanup(*it);
 154                 }
 155         }
 156         CURL * alloc()
 157         {
 158                 CURL *curl;
 159                 if (handles.empty()) {
 160                         curl = curl_easy_init();
 161                         if (curl == NULL) {
 162                                 errorstream<<"curl_easy_init returned NULL"<<std::endl;
 163                         }
 164                 }
 165                 else {
 166                         curl = handles.front();
 167                         handles.pop_front();
 168                 }
 169                 return curl;
 170         }
 171         void free(CURL *handle)
 172         {
 173                 if (handle)
 174                         handles.push_back(handle);
 175         }
 176 };
 177
 178 class HTTPFetchOngoing
 179 {
 180 public:
 181         HTTPFetchOngoing(HTTPFetchRequest request, CurlHandlePool *pool);
 182         ~HTTPFetchOngoing();
 183
 184         CURLcode start(CURLM *multi);
 185         const HTTPFetchResult * complete(CURLcode res);
 186
 187         const HTTPFetchRequest &getRequest()    const { return request; };
 188         const CURL             *getEasyHandle() const { return curl; };
 189
 190 private:
 191         CurlHandlePool *pool;
 192         CURL *curl;
 193         CURLM *multi;
 194         HTTPFetchRequest request;
 195         HTTPFetchResult result;
 196         std::ostringstream oss;
 197         char *post_fields;
 198         struct curl_slist *http_header;
 199         curl_httppost *post;
 200 };
 201
 202
 203 HTTPFetchOngoing::HTTPFetchOngoing(HTTPFetchRequest request_, CurlHandlePool *pool_):
 204         pool(pool_),
 205         curl(NULL),
 206         multi(NULL),
 207         request(request_),
 208         result(request_),
 209         oss(std::ios::binary),
 210         http_header(NULL),
 211         post(NULL)
 212 {
 213         curl = pool->alloc();
 214         if (curl == NULL) {
 215                 return;
 216         }
 217
 218         // Set static cURL options
 219         curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
 220         curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
 221         curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
 222         curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 1);
 223
 224         std::string bind_address = g_settings->get("bind_address");
 225         if (!bind_address.empty()) {
 226                 curl_easy_setopt(curl, CURLOPT_INTERFACE, bind_address.c_str());
 227         }
 228
 229 #if LIBCURL_VERSION_NUM >= 0x071304
 230         // Restrict protocols so that curl vulnerabilities in
 231         // other protocols don't affect us.
 232         // These settings were introduced in curl 7.19.4.
 233         long protocols =
 234                 CURLPROTO_HTTP |
 235                 CURLPROTO_HTTPS |
 236                 CURLPROTO_FTP |
 237                 CURLPROTO_FTPS;
 238         curl_easy_setopt(curl, CURLOPT_PROTOCOLS, protocols);
 239         curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS, protocols);
 240 #endif
 241
 242         // Set cURL options based on HTTPFetchRequest
 243         curl_easy_setopt(curl, CURLOPT_URL,
 244                         request.url.c_str());
 245         curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS,
 246                         request.timeout);
 247         curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS,
 248                         request.connect_timeout);
 249
 250         if (request.useragent != "")
 251                 curl_easy_setopt(curl, CURLOPT_USERAGENT, request.useragent.c_str());
 252
 253         // Set up a write callback that writes to the
 254         // ostringstream ongoing->oss, unless the data
 255         // is to be discarded
 256         if (request.caller == HTTPFETCH_DISCARD) {
 257                 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
 258                                 httpfetch_discardfunction);
 259                 curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
 260         } else {
 261                 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
 262                                 httpfetch_writefunction);
 263                 curl_easy_setopt(curl, CURLOPT_WRITEDATA, &oss);
 264         }
 265
 266         // Set POST (or GET) data
 267         if (request.post_fields.empty()) {
 268                 curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
 269         } else if (request.multipart) {
 270                 curl_httppost *last = NULL;
 271                 for (std::map<std::string, std::string>::iterator it =
 272                                         request.post_fields.begin();
 273                                 it != request.post_fields.end(); ++it) {
 274                         curl_formadd(&post, &last,
 275                                         CURLFORM_NAMELENGTH, it->first.size(),
 276                                         CURLFORM_PTRNAME, it->first.c_str(),
 277                                         CURLFORM_CONTENTSLENGTH, it->second.size(),
 278                                         CURLFORM_PTRCONTENTS, it->second.c_str(),
 279                                         CURLFORM_END);
 280                 }
 281                 curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);
 282                 // request.post_fields must now *never* be
 283                 // modified until CURLOPT_HTTPPOST is cleared
 284         } else if (request.post_data.empty()) {
 285                 curl_easy_setopt(curl, CURLOPT_POST, 1);
 286                 std::string str;
 287                 for (std::map<std::string, std::string>::iterator it =
 288                                         request.post_fields.begin();
 289                                 it != request.post_fields.end();
 290                                 ++it) {
 291                         if (str != "")
 292                                 str += "&";
 293                         str += urlencode(it->first);
 294                         str += "=";
 295                         str += urlencode(it->second);
 296                 }
 297                 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
 298                                 str.size());
 299                 curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS,
 300                                 str.c_str());
 301         } else {
 302                 curl_easy_setopt(curl, CURLOPT_POST, 1);
 303                 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
 304                                 request.post_data.size());
 305                 curl_easy_setopt(curl, CURLOPT_POSTFIELDS,
 306                                 request.post_data.c_str());
 307                 // request.post_data must now *never* be
 308                 // modified until CURLOPT_POSTFIELDS is cleared
 309         }
 310         // Set additional HTTP headers
 311         for (std::vector<std::string>::iterator it = request.extra_headers.begin();
 312                         it != request.extra_headers.end(); ++it) {
 313                 http_header = curl_slist_append(http_header, it->c_str());
 314         }
 315         curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);
 316
 317         if (!g_settings->getBool("curl_verify_cert")) {
 318                 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
 319         }
 320 }
 321
 322 CURLcode HTTPFetchOngoing::start(CURLM *multi_)
 323 {
 324         if (!curl)
 325                 return CURLE_FAILED_INIT;
 326
 327         if (!multi_) {
 328                 // Easy interface (sync)
 329                 return curl_easy_perform(curl);
 330         }
 331
 332         // Multi interface (async)
 333         CURLMcode mres = curl_multi_add_handle(multi_, curl);
 334         if (mres != CURLM_OK) {
 335                 errorstream << "curl_multi_add_handle"
 336                         << " returned error code " << mres
 337                         << std::endl;
 338                 return CURLE_FAILED_INIT;
 339         }
 340         multi = multi_; // store for curl_multi_remove_handle
 341         return CURLE_OK;
 342 }
 343
 344 const HTTPFetchResult * HTTPFetchOngoing::complete(CURLcode res)
 345 {
 346         result.succeeded = (res == CURLE_OK);
 347         result.timeout = (res == CURLE_OPERATION_TIMEDOUT);
 348         result.data = oss.str();
 349
 350         // Get HTTP/FTP response code
 351         result.response_code = 0;
 352         if (curl && (curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE,
 353                                 &result.response_code) != CURLE_OK)) {
 354                 // We failed to get a return code, make sure it is still 0
 355                 result.response_code = 0;
 356         }
 357
 358         if (res != CURLE_OK) {
 359                 errorstream << request.url << " not found ("
 360                         << curl_easy_strerror(res) << ")"
 361                         << " (response code " << result.response_code << ")"
 362                         << std::endl;
 363         }
 364
 365         return &result;
 366 }
 367
 368 HTTPFetchOngoing::~HTTPFetchOngoing()
 369 {
 370         if (multi) {
 371                 CURLMcode mres = curl_multi_remove_handle(multi, curl);
 372                 if (mres != CURLM_OK) {
 373                         errorstream << "curl_multi_remove_handle"
 374                                 << " returned error code " << mres
 375                                 << std::endl;
 376                 }
 377         }
 378
 379         // Set safe options for the reusable cURL handle
 380         curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
 381                         httpfetch_discardfunction);
 382         curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
 383         curl_easy_setopt(curl, CURLOPT_POSTFIELDS, NULL);
 384         if (http_header) {
 385                 curl_easy_setopt(curl, CURLOPT_HTTPHEADER, NULL);
 386                 curl_slist_free_all(http_header);
 387         }
 388         if (post) {
 389                 curl_easy_setopt(curl, CURLOPT_HTTPPOST, NULL);
 390                 curl_formfree(post);
 391         }
 392
 393         // Store the cURL handle for reuse
 394         pool->free(curl);
 395 }
 396
 397
 398 class CurlFetchThread : public JThread
 399 {
 400 protected:
 401         enum RequestType {
 402                 RT_FETCH,
 403                 RT_CLEAR,
 404                 RT_WAKEUP,
 405         };
 406
 407         struct Request {
 408                 RequestType type;
 409                 HTTPFetchRequest fetch_request;
 410                 Event *event;
 411         };
 412
 413         CURLM *m_multi;
 414         MutexedQueue<Request> m_requests;
 415         size_t m_parallel_limit;
 416
 417         // Variables exclusively used within thread
 418         std::vector<HTTPFetchOngoing*> m_all_ongoing;
 419         std::list<HTTPFetchRequest> m_queued_fetches;
 420
 421 public:
 422         CurlFetchThread(int parallel_limit)
 423         {
 424                 if (parallel_limit >= 1)
 425                         m_parallel_limit = parallel_limit;
 426                 else
 427                         m_parallel_limit = 1;
 428         }
 429
 430         void requestFetch(const HTTPFetchRequest &fetch_request)
 431         {
 432                 Request req;
 433                 req.type = RT_FETCH;
 434                 req.fetch_request = fetch_request;
 435                 req.event = NULL;
 436                 m_requests.push_back(req);
 437         }
 438
 439         void requestClear(unsigned long caller, Event *event)
 440         {
 441                 Request req;
 442                 req.type = RT_CLEAR;
 443                 req.fetch_request.caller = caller;
 444                 req.event = event;
 445                 m_requests.push_back(req);
 446         }
 447
 448         void requestWakeUp()
 449         {
 450                 Request req;
 451                 req.type = RT_WAKEUP;
 452                 req.event = NULL;
 453                 m_requests.push_back(req);
 454         }
 455
 456 protected:
 457         // Handle a request from some other thread
 458         // E.g. new fetch; clear fetches for one caller; wake up
 459         void processRequest(const Request &req)
 460         {
 461                 if (req.type == RT_FETCH) {
 462                         // New fetch, queue until there are less
 463                         // than m_parallel_limit ongoing fetches
 464                         m_queued_fetches.push_back(req.fetch_request);
 465
 466                         // see processQueued() for what happens next
 467
 468                 }
 469                 else if (req.type == RT_CLEAR) {
 470                         unsigned long caller = req.fetch_request.caller;
 471
 472                         // Abort all ongoing fetches for the caller
 473                         for (std::vector<HTTPFetchOngoing*>::iterator
 474                                         it = m_all_ongoing.begin();
 475                                         it != m_all_ongoing.end();) {
 476                                 if ((*it)->getRequest().caller == caller) {
 477                                         delete (*it);
 478                                         it = m_all_ongoing.erase(it);
 479                                 } else {
 480                                         ++it;
 481                                 }
 482                         }
 483
 484                         // Also abort all queued fetches for the caller
 485                         for (std::list<HTTPFetchRequest>::iterator
 486                                         it = m_queued_fetches.begin();
 487                                         it != m_queued_fetches.end();) {
 488                                 if ((*it).caller == caller)
 489                                         it = m_queued_fetches.erase(it);
 490                                 else
 491                                         ++it;
 492                         }
 493                 }
 494                 else if (req.type == RT_WAKEUP) {
 495                         // Wakeup: Nothing to do, thread is awake at this point
 496                 }
 497
 498                 if (req.event != NULL)
 499                         req.event->signal();
 500         }
 501
 502         // Start new ongoing fetches if m_parallel_limit allows
 503         void processQueued(CurlHandlePool *pool)
 504         {
 505                 while (m_all_ongoing.size() < m_parallel_limit &&
 506                                 !m_queued_fetches.empty()) {
 507                         HTTPFetchRequest request = m_queued_fetches.front();
 508                         m_queued_fetches.pop_front();
 509
 510                         // Create ongoing fetch data and make a cURL handle
 511                         // Set cURL options based on HTTPFetchRequest
 512                         HTTPFetchOngoing *ongoing =
 513                                 new HTTPFetchOngoing(request, pool);
 514
 515                         // Initiate the connection (curl_multi_add_handle)
 516                         CURLcode res = ongoing->start(m_multi);
 517                         if (res == CURLE_OK) {
 518                                 m_all_ongoing.push_back(ongoing);
 519                         }
 520                         else {
 521                                 httpfetch_deliver_result(*ongoing->complete(res));
 522                                 delete ongoing;
 523                         }
 524                 }
 525         }
 526
 527         // Process CURLMsg (indicates completion of a fetch)
 528         void processCurlMessage(CURLMsg *msg)
 529         {
 530                 // Determine which ongoing fetch the message pertains to
 531                 size_t i = 0;
 532                 bool found = false;
 533                 for (i = 0; i < m_all_ongoing.size(); ++i) {
 534                         if (m_all_ongoing[i]->getEasyHandle() == msg->easy_handle) {
 535                                 found = true;
 536                                 break;
 537                         }
 538                 }
 539                 if (msg->msg == CURLMSG_DONE && found) {
 540                         // m_all_ongoing[i] succeeded or failed.
 541                         HTTPFetchOngoing *ongoing = m_all_ongoing[i];
 542                         httpfetch_deliver_result(*ongoing->complete(msg->data.result));
 543                         delete ongoing;
 544                         m_all_ongoing.erase(m_all_ongoing.begin() + i);
 545                 }
 546         }
 547
 548         // Wait for a request from another thread, or timeout elapses
 549         void waitForRequest(long timeout)
 550         {
 551                 if (m_queued_fetches.empty()) {
 552                         try {
 553                                 Request req = m_requests.pop_front(timeout);
 554                                 processRequest(req);
 555                         }
 556                         catch (ItemNotFoundException &e) {}
 557                 }
 558         }
 559
 560         // Wait until some IO happens, or timeout elapses
 561         void waitForIO(long timeout)
 562         {
 563                 fd_set read_fd_set;
 564                 fd_set write_fd_set;
 565                 fd_set exc_fd_set;
 566                 int max_fd;
 567                 long select_timeout = -1;
 568                 struct timeval select_tv;
 569                 CURLMcode mres;
 570
 571                 FD_ZERO(&read_fd_set);
 572                 FD_ZERO(&write_fd_set);
 573                 FD_ZERO(&exc_fd_set);
 574
 575                 mres = curl_multi_fdset(m_multi, &read_fd_set,
 576                                 &write_fd_set, &exc_fd_set, &max_fd);
 577                 if (mres != CURLM_OK) {
 578                         errorstream<<"curl_multi_fdset"
 579                                 <<" returned error code "<<mres
 580                                 <<std::endl;
 581                         select_timeout = 0;
 582                 }
 583
 584                 mres = curl_multi_timeout(m_multi, &select_timeout);
 585                 if (mres != CURLM_OK) {
 586                         errorstream<<"curl_multi_timeout"
 587                                 <<" returned error code "<<mres
 588                                 <<std::endl;
 589                         select_timeout = 0;
 590                 }
 591
 592                 // Limit timeout so new requests get through
 593                 if (select_timeout < 0 || select_timeout > timeout)
 594                         select_timeout = timeout;
 595
 596                 if (select_timeout > 0) {
 597                         // in Winsock it is forbidden to pass three empty
 598                         // fd_sets to select(), so in that case use sleep_ms
 599                         if (max_fd != -1) {
 600                                 select_tv.tv_sec = select_timeout / 1000;
 601                                 select_tv.tv_usec = (select_timeout % 1000) * 1000;
 602                                 int retval = select(max_fd + 1, &read_fd_set,
 603                                                 &write_fd_set, &exc_fd_set,
 604                                                 &select_tv);
 605                                 if (retval == -1) {
 606                                         #ifdef _WIN32
 607                                         errorstream<<"select returned error code "
 608                                                 <<WSAGetLastError()<<std::endl;
 609                                         #else
 610                                         errorstream<<"select returned error code "
 611                                                 <<errno<<std::endl;
 612                                         #endif
 613                                 }
 614                         }
 615                         else {
 616                                 sleep_ms(select_timeout);
 617                         }
 618                 }
 619         }
 620
 621         void * Thread()
 622         {
 623                 ThreadStarted();
 624                 log_register_thread("CurlFetchThread");
 625                 DSTACK(__FUNCTION_NAME);
 626
 627                 porting::setThreadName("CurlFetchThread");
 628
 629                 CurlHandlePool pool;
 630
 631                 m_multi = curl_multi_init();
 632                 if (m_multi == NULL) {
 633                         errorstream<<"curl_multi_init returned NULL\n";
 634                         return NULL;
 635                 }
 636
 637                 assert(m_all_ongoing.empty());
 638
 639                 while (!StopRequested()) {
 640                         BEGIN_DEBUG_EXCEPTION_HANDLER
 641
 642                         /*
 643                                 Handle new async requests
 644                         */
 645
 646                         while (!m_requests.empty()) {
 647                                 Request req = m_requests.pop_frontNoEx();
 648                                 processRequest(req);
 649                         }
 650                         processQueued(&pool);
 651
 652                         /*
 653                                 Handle ongoing async requests
 654                         */
 655
 656                         int still_ongoing = 0;
 657                         while (curl_multi_perform(m_multi, &still_ongoing) ==
 658                                         CURLM_CALL_MULTI_PERFORM)
 659                                 /* noop */;
 660
 661                         /*
 662                                 Handle completed async requests
 663                         */
 664                         if (still_ongoing < (int) m_all_ongoing.size()) {
 665                                 CURLMsg *msg;
 666                                 int msgs_in_queue;
 667                                 msg = curl_multi_info_read(m_multi, &msgs_in_queue);
 668                                 while (msg != NULL) {
 669                                         processCurlMessage(msg);
 670                                         msg = curl_multi_info_read(m_multi, &msgs_in_queue);
 671                                 }
 672                         }
 673
 674                         /*
 675                                 If there are ongoing requests, wait for data
 676                                 (with a timeout of 100ms so that new requests
 677                                 can be processed).
 678
 679                                 If no ongoing requests, wait for a new request.
 680                                 (Possibly an empty request that signals
 681                                 that the thread should be stopped.)
 682                         */
 683                         if (m_all_ongoing.empty())
 684                                 waitForRequest(100000000);
 685                         else
 686                                 waitForIO(100);
 687
 688                         END_DEBUG_EXCEPTION_HANDLER(errorstream)
 689                 }
 690
 691                 // Call curl_multi_remove_handle and cleanup easy handles
 692                 for (size_t i = 0; i < m_all_ongoing.size(); ++i) {
 693                         delete m_all_ongoing[i];
 694                 }
 695                 m_all_ongoing.clear();
 696
 697                 m_queued_fetches.clear();
 698
 699                 CURLMcode mres = curl_multi_cleanup(m_multi);
 700                 if (mres != CURLM_OK) {
 701                         errorstream<<"curl_multi_cleanup"
 702                                 <<" returned error code "<<mres
 703                                 <<std::endl;
 704                 }
 705
 706                 return NULL;
 707         }
 708 };
 709
 710 CurlFetchThread *g_httpfetch_thread = NULL;
 711
 712 void httpfetch_init(int parallel_limit)
 713 {
 714         verbosestream<<"httpfetch_init: parallel_limit="<<parallel_limit
 715                         <<std::endl;
 716
 717         CURLcode res = curl_global_init(CURL_GLOBAL_DEFAULT);
 718         assert(res == CURLE_OK);
 719
 720         g_httpfetch_thread = new CurlFetchThread(parallel_limit);
 721 }
 722
 723 void httpfetch_cleanup()
 724 {
 725         verbosestream<<"httpfetch_cleanup: cleaning up"<<std::endl;
 726
 727         g_httpfetch_thread->Stop();
 728         g_httpfetch_thread->requestWakeUp();
 729         g_httpfetch_thread->Wait();
 730         delete g_httpfetch_thread;
 731
 732         curl_global_cleanup();
 733 }
 734
 735 void httpfetch_async(const HTTPFetchRequest &fetch_request)
 736 {
 737         g_httpfetch_thread->requestFetch(fetch_request);
 738         if (!g_httpfetch_thread->IsRunning())
 739                 g_httpfetch_thread->Start();
 740 }
 741
 742 static void httpfetch_request_clear(unsigned long caller)
 743 {
 744         if (g_httpfetch_thread->IsRunning()) {
 745                 Event event;
 746                 g_httpfetch_thread->requestClear(caller, &event);
 747                 event.wait();
 748         }
 749         else {
 750                 g_httpfetch_thread->requestClear(caller, NULL);
 751         }
 752 }
 753
 754 void httpfetch_sync(const HTTPFetchRequest &fetch_request,
 755                 HTTPFetchResult &fetch_result)
 756 {
 757         // Create ongoing fetch data and make a cURL handle
 758         // Set cURL options based on HTTPFetchRequest
 759         CurlHandlePool pool;
 760         HTTPFetchOngoing ongoing(fetch_request, &pool);
 761         // Do the fetch (curl_easy_perform)
 762         CURLcode res = ongoing.start(NULL);
 763         // Update fetch result
 764         fetch_result = *ongoing.complete(res);
 765 }
 766
 767 #else  // USE_CURL
 768
 769 /*
 770         USE_CURL is off:
 771
 772         Dummy httpfetch implementation that always returns an error.
 773 */
 774
 775 void httpfetch_init(int parallel_limit)
 776 {
 777 }
 778
 779 void httpfetch_cleanup()
 780 {
 781 }
 782
 783 void httpfetch_async(const HTTPFetchRequest &fetch_request)
 784 {
 785         errorstream << "httpfetch_async: unable to fetch " << fetch_request.url
 786                         << " because USE_CURL=0" << std::endl;
 787
 788         HTTPFetchResult fetch_result(fetch_request); // sets succeeded = false etc.
 789         httpfetch_deliver_result(fetch_result);
 790 }
 791
 792 static void httpfetch_request_clear(unsigned long caller)
 793 {
 794 }
 795
 796 void httpfetch_sync(const HTTPFetchRequest &fetch_request,
 797                 HTTPFetchResult &fetch_result)
 798 {
 799         errorstream << "httpfetch_sync: unable to fetch " << fetch_request.url
 800                         << " because USE_CURL=0" << std::endl;
 801
 802         fetch_result = HTTPFetchResult(fetch_request); // sets succeeded = false etc.
 803 }
 804
 805 #endif  // USE_CURL