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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 2012 - 2017, Daniel Stenberg, <daniel (at) haxx.se>, et al.
      9  *
     10  * This software is licensed as described in the file COPYING, which
     11  * you should have received as part of this distribution. The terms
     12  * are also available at https://curl.haxx.se/docs/copyright.html.
     13  *
     14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
     15  * copies of the Software, and permit persons to whom the Software is
     16  * furnished to do so, under the terms of the COPYING file.
     17  *
     18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
     19  * KIND, either express or implied.
     20  *
     21  ***************************************************************************/
     22 
     23 /* <DESC>
     24  * demonstrate the use of multi socket interface with boost::asio
     25  * </DESC>
     26  */
     27 /*
     28  * This program is in c++ and uses boost::asio instead of libevent/libev.
     29  * Requires boost::asio, boost::bind and boost::system
     30  *
     31  * This is an adaptation of libcurl's "hiperfifo.c" and "evhiperfifo.c"
     32  * sample programs. This example implements a subset of the functionality from
     33  * hiperfifo.c, for full functionality refer hiperfifo.c or evhiperfifo.c
     34  *
     35  * Written by Lijo Antony based on hiperfifo.c by Jeff Pohlmeyer
     36  *
     37  * When running, the program creates an easy handle for a URL and
     38  * uses the curl_multi API to fetch it.
     39  *
     40  * Note:
     41  *  For the sake of simplicity, URL is hard coded to "www.google.com"
     42  *
     43  * This is purely a demo app, all retrieved data is simply discarded by the
     44  * write callback.
     45  */
     46 
     47 
     48 #include <curl/curl.h>
     49 #include <boost/asio.hpp>
     50 #include <boost/bind.hpp>
     51 #include <iostream>
     52 
     53 #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
     54 
     55 /* boost::asio related objects
     56  * using global variables for simplicity
     57  */
     58 boost::asio::io_service io_service;
     59 boost::asio::deadline_timer timer(io_service);
     60 std::map<curl_socket_t, boost::asio::ip::tcp::socket *> socket_map;
     61 
     62 /* Global information, common to all connections */
     63 typedef struct _GlobalInfo
     64 {
     65   CURLM *multi;
     66   int still_running;
     67 } GlobalInfo;
     68 
     69 /* Information associated with a specific easy handle */
     70 typedef struct _ConnInfo
     71 {
     72   CURL *easy;
     73   char *url;
     74   GlobalInfo *global;
     75   char error[CURL_ERROR_SIZE];
     76 } ConnInfo;
     77 
     78 static void timer_cb(const boost::system::error_code & error, GlobalInfo *g);
     79 
     80 /* Update the event timer after curl_multi library calls */
     81 static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
     82 {
     83   fprintf(MSG_OUT, "\nmulti_timer_cb: timeout_ms %ld", timeout_ms);
     84 
     85   /* cancel running timer */
     86   timer.cancel();
     87 
     88   if(timeout_ms > 0) {
     89     /* update timer */
     90     timer.expires_from_now(boost::posix_time::millisec(timeout_ms));
     91     timer.async_wait(boost::bind(&timer_cb, _1, g));
     92   }
     93   else if(timeout_ms == 0) {
     94     /* call timeout function immediately */
     95     boost::system::error_code error; /*success*/
     96     timer_cb(error, g);
     97   }
     98 
     99   return 0;
    100 }
    101 
    102 /* Die if we get a bad CURLMcode somewhere */
    103 static void mcode_or_die(const char *where, CURLMcode code)
    104 {
    105   if(CURLM_OK != code) {
    106     const char *s;
    107     switch(code) {
    108     case CURLM_CALL_MULTI_PERFORM:
    109       s = "CURLM_CALL_MULTI_PERFORM";
    110       break;
    111     case CURLM_BAD_HANDLE:
    112       s = "CURLM_BAD_HANDLE";
    113       break;
    114     case CURLM_BAD_EASY_HANDLE:
    115       s = "CURLM_BAD_EASY_HANDLE";
    116       break;
    117     case CURLM_OUT_OF_MEMORY:
    118       s = "CURLM_OUT_OF_MEMORY";
    119       break;
    120     case CURLM_INTERNAL_ERROR:
    121       s = "CURLM_INTERNAL_ERROR";
    122       break;
    123     case CURLM_UNKNOWN_OPTION:
    124       s = "CURLM_UNKNOWN_OPTION";
    125       break;
    126     case CURLM_LAST:
    127       s = "CURLM_LAST";
    128       break;
    129     default:
    130       s = "CURLM_unknown";
    131       break;
    132     case CURLM_BAD_SOCKET:
    133       s = "CURLM_BAD_SOCKET";
    134       fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
    135       /* ignore this error */
    136       return;
    137     }
    138 
    139     fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
    140 
    141     exit(code);
    142   }
    143 }
    144 
    145 /* Check for completed transfers, and remove their easy handles */
    146 static void check_multi_info(GlobalInfo *g)
    147 {
    148   char *eff_url;
    149   CURLMsg *msg;
    150   int msgs_left;
    151   ConnInfo *conn;
    152   CURL *easy;
    153   CURLcode res;
    154 
    155   fprintf(MSG_OUT, "\nREMAINING: %d", g->still_running);
    156 
    157   while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
    158     if(msg->msg == CURLMSG_DONE) {
    159       easy = msg->easy_handle;
    160       res = msg->data.result;
    161       curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
    162       curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
    163       fprintf(MSG_OUT, "\nDONE: %s => (%d) %s", eff_url, res, conn->error);
    164       curl_multi_remove_handle(g->multi, easy);
    165       free(conn->url);
    166       curl_easy_cleanup(easy);
    167       free(conn);
    168     }
    169   }
    170 }
    171 
    172 /* Called by asio when there is an action on a socket */
    173 static void event_cb(GlobalInfo *g, curl_socket_t s,
    174                      int action, const boost::system::error_code & error,
    175                      int *fdp)
    176 {
    177   fprintf(MSG_OUT, "\nevent_cb: action=%d", action);
    178 
    179   if(socket_map.find(s) == socket_map.end()) {
    180     fprintf(MSG_OUT, "\nevent_cb: socket already closed");
    181     return;
    182   }
    183 
    184   /* make sure the event matches what are wanted */
    185   if(*fdp == action || *fdp == CURL_POLL_INOUT) {
    186     CURLMcode rc;
    187     if(error)
    188       action = CURL_CSELECT_ERR;
    189     rc = curl_multi_socket_action(g->multi, s, action, &g->still_running);
    190 
    191     mcode_or_die("event_cb: curl_multi_socket_action", rc);
    192     check_multi_info(g);
    193 
    194     if(g->still_running <= 0) {
    195       fprintf(MSG_OUT, "\nlast transfer done, kill timeout");
    196       timer.cancel();
    197     }
    198 
    199     /* keep on watching.
    200      * the socket may have been closed and/or fdp may have been changed
    201      * in curl_multi_socket_action(), so check them both */
    202     if(!error && socket_map.find(s) != socket_map.end() &&
    203        (*fdp == action || *fdp == CURL_POLL_INOUT)) {
    204       boost::asio::ip::tcp::socket *tcp_socket = socket_map.find(s)->second;
    205 
    206       if(action == CURL_POLL_IN) {
    207         tcp_socket->async_read_some(boost::asio::null_buffers(),
    208                                     boost::bind(&event_cb, g, s,
    209                                                 action, _1, fdp));
    210       }
    211       if(action == CURL_POLL_OUT) {
    212         tcp_socket->async_write_some(boost::asio::null_buffers(),
    213                                      boost::bind(&event_cb, g, s,
    214                                                  action, _1, fdp));
    215       }
    216     }
    217   }
    218 }
    219 
    220 /* Called by asio when our timeout expires */
    221 static void timer_cb(const boost::system::error_code & error, GlobalInfo *g)
    222 {
    223   if(!error) {
    224     fprintf(MSG_OUT, "\ntimer_cb: ");
    225 
    226     CURLMcode rc;
    227     rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0,
    228                                   &g->still_running);
    229 
    230     mcode_or_die("timer_cb: curl_multi_socket_action", rc);
    231     check_multi_info(g);
    232   }
    233 }
    234 
    235 /* Clean up any data */
    236 static void remsock(int *f, GlobalInfo *g)
    237 {
    238   fprintf(MSG_OUT, "\nremsock: ");
    239 
    240   if(f) {
    241     free(f);
    242   }
    243 }
    244 
    245 static void setsock(int *fdp, curl_socket_t s, CURL *e, int act, int oldact,
    246                     GlobalInfo *g)
    247 {
    248   fprintf(MSG_OUT, "\nsetsock: socket=%d, act=%d, fdp=%p", s, act, fdp);
    249 
    250   std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it =
    251     socket_map.find(s);
    252 
    253   if(it == socket_map.end()) {
    254     fprintf(MSG_OUT, "\nsocket %d is a c-ares socket, ignoring", s);
    255     return;
    256   }
    257 
    258   boost::asio::ip::tcp::socket * tcp_socket = it->second;
    259 
    260   *fdp = act;
    261 
    262   if(act == CURL_POLL_IN) {
    263     fprintf(MSG_OUT, "\nwatching for socket to become readable");
    264     if(oldact != CURL_POLL_IN && oldact != CURL_POLL_INOUT) {
    265       tcp_socket->async_read_some(boost::asio::null_buffers(),
    266                                   boost::bind(&event_cb, g, s,
    267                                               CURL_POLL_IN, _1, fdp));
    268     }
    269   }
    270   else if(act == CURL_POLL_OUT) {
    271     fprintf(MSG_OUT, "\nwatching for socket to become writable");
    272     if(oldact != CURL_POLL_OUT && oldact != CURL_POLL_INOUT) {
    273       tcp_socket->async_write_some(boost::asio::null_buffers(),
    274                                    boost::bind(&event_cb, g, s,
    275                                                CURL_POLL_OUT, _1, fdp));
    276     }
    277   }
    278   else if(act == CURL_POLL_INOUT) {
    279     fprintf(MSG_OUT, "\nwatching for socket to become readable & writable");
    280     if(oldact != CURL_POLL_IN && oldact != CURL_POLL_INOUT) {
    281       tcp_socket->async_read_some(boost::asio::null_buffers(),
    282                                   boost::bind(&event_cb, g, s,
    283                                               CURL_POLL_IN, _1, fdp));
    284     }
    285     if(oldact != CURL_POLL_OUT && oldact != CURL_POLL_INOUT) {
    286       tcp_socket->async_write_some(boost::asio::null_buffers(),
    287                                    boost::bind(&event_cb, g, s,
    288                                                CURL_POLL_OUT, _1, fdp));
    289     }
    290   }
    291 }
    292 
    293 static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
    294 {
    295   /* fdp is used to store current action */
    296   int *fdp = (int *) calloc(sizeof(int), 1);
    297 
    298   setsock(fdp, s, easy, action, 0, g);
    299   curl_multi_assign(g->multi, s, fdp);
    300 }
    301 
    302 /* CURLMOPT_SOCKETFUNCTION */
    303 static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
    304 {
    305   fprintf(MSG_OUT, "\nsock_cb: socket=%d, what=%d, sockp=%p", s, what, sockp);
    306 
    307   GlobalInfo *g = (GlobalInfo*) cbp;
    308   int *actionp = (int *) sockp;
    309   const char *whatstr[] = { "none", "IN", "OUT", "INOUT", "REMOVE"};
    310 
    311   fprintf(MSG_OUT,
    312           "\nsocket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
    313 
    314   if(what == CURL_POLL_REMOVE) {
    315     fprintf(MSG_OUT, "\n");
    316     remsock(actionp, g);
    317   }
    318   else {
    319     if(!actionp) {
    320       fprintf(MSG_OUT, "\nAdding data: %s", whatstr[what]);
    321       addsock(s, e, what, g);
    322     }
    323     else {
    324       fprintf(MSG_OUT,
    325               "\nChanging action from %s to %s",
    326               whatstr[*actionp], whatstr[what]);
    327       setsock(actionp, s, e, what, *actionp, g);
    328     }
    329   }
    330 
    331   return 0;
    332 }
    333 
    334 /* CURLOPT_WRITEFUNCTION */
    335 static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
    336 {
    337   size_t written = size * nmemb;
    338   char *pBuffer = (char *)malloc(written + 1);
    339 
    340   strncpy(pBuffer, (const char *)ptr, written);
    341   pBuffer[written] = '\0';
    342 
    343   fprintf(MSG_OUT, "%s", pBuffer);
    344 
    345   free(pBuffer);
    346 
    347   return written;
    348 }
    349 
    350 /* CURLOPT_PROGRESSFUNCTION */
    351 static int prog_cb(void *p, double dltotal, double dlnow, double ult,
    352                    double uln)
    353 {
    354   ConnInfo *conn = (ConnInfo *)p;
    355 
    356   (void)ult;
    357   (void)uln;
    358 
    359   fprintf(MSG_OUT, "\nProgress: %s (%g/%g)", conn->url, dlnow, dltotal);
    360   fprintf(MSG_OUT, "\nProgress: %s (%g)", conn->url, ult);
    361 
    362   return 0;
    363 }
    364 
    365 /* CURLOPT_OPENSOCKETFUNCTION */
    366 static curl_socket_t opensocket(void *clientp, curlsocktype purpose,
    367                                 struct curl_sockaddr *address)
    368 {
    369   fprintf(MSG_OUT, "\nopensocket :");
    370 
    371   curl_socket_t sockfd = CURL_SOCKET_BAD;
    372 
    373   /* restrict to IPv4 */
    374   if(purpose == CURLSOCKTYPE_IPCXN && address->family == AF_INET) {
    375     /* create a tcp socket object */
    376     boost::asio::ip::tcp::socket *tcp_socket =
    377       new boost::asio::ip::tcp::socket(io_service);
    378 
    379     /* open it and get the native handle*/
    380     boost::system::error_code ec;
    381     tcp_socket->open(boost::asio::ip::tcp::v4(), ec);
    382 
    383     if(ec) {
    384       /* An error occurred */
    385       std::cout << std::endl << "Couldn't open socket [" << ec << "][" <<
    386         ec.message() << "]";
    387       fprintf(MSG_OUT, "\nERROR: Returning CURL_SOCKET_BAD to signal error");
    388     }
    389     else {
    390       sockfd = tcp_socket->native_handle();
    391       fprintf(MSG_OUT, "\nOpened socket %d", sockfd);
    392 
    393       /* save it for monitoring */
    394       socket_map.insert(std::pair<curl_socket_t,
    395                         boost::asio::ip::tcp::socket *>(sockfd, tcp_socket));
    396     }
    397   }
    398 
    399   return sockfd;
    400 }
    401 
    402 /* CURLOPT_CLOSESOCKETFUNCTION */
    403 static int close_socket(void *clientp, curl_socket_t item)
    404 {
    405   fprintf(MSG_OUT, "\nclose_socket : %d", item);
    406 
    407   std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it =
    408     socket_map.find(item);
    409 
    410   if(it != socket_map.end()) {
    411     delete it->second;
    412     socket_map.erase(it);
    413   }
    414 
    415   return 0;
    416 }
    417 
    418 /* Create a new easy handle, and add it to the global curl_multi */
    419 static void new_conn(char *url, GlobalInfo *g)
    420 {
    421   ConnInfo *conn;
    422   CURLMcode rc;
    423 
    424   conn = (ConnInfo *) calloc(1, sizeof(ConnInfo));
    425 
    426   conn->easy = curl_easy_init();
    427   if(!conn->easy) {
    428     fprintf(MSG_OUT, "\ncurl_easy_init() failed, exiting!");
    429     exit(2);
    430   }
    431 
    432   conn->global = g;
    433   conn->url = strdup(url);
    434   curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
    435   curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
    436   curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
    437   curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
    438   curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
    439   curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
    440   curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 1L);
    441   curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
    442   curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
    443   curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
    444   curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
    445 
    446   /* call this function to get a socket */
    447   curl_easy_setopt(conn->easy, CURLOPT_OPENSOCKETFUNCTION, opensocket);
    448 
    449   /* call this function to close a socket */
    450   curl_easy_setopt(conn->easy, CURLOPT_CLOSESOCKETFUNCTION, close_socket);
    451 
    452   fprintf(MSG_OUT,
    453           "\nAdding easy %p to multi %p (%s)", conn->easy, g->multi, url);
    454   rc = curl_multi_add_handle(g->multi, conn->easy);
    455   mcode_or_die("new_conn: curl_multi_add_handle", rc);
    456 
    457   /* note that the add_handle() will set a time-out to trigger very soon so
    458      that the necessary socket_action() call will be called by this app */
    459 }
    460 
    461 int main(int argc, char **argv)
    462 {
    463   GlobalInfo g;
    464 
    465   (void)argc;
    466   (void)argv;
    467 
    468   memset(&g, 0, sizeof(GlobalInfo));
    469   g.multi = curl_multi_init();
    470 
    471   curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
    472   curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
    473   curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
    474   curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
    475 
    476   new_conn((char *)"www.google.com", &g);  /* add a URL */
    477 
    478   /* enter io_service run loop */
    479   io_service.run();
    480 
    481   curl_multi_cleanup(g.multi);
    482 
    483   fprintf(MSG_OUT, "\ndone.\n");
    484 
    485   return 0;
    486 }
    487