1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 2012 - 2018, Daniel Stenberg, <daniel@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 * WARNING: This example program is known to have flaws:
48 * https://github.com/curl/curl/issues/2407
49 *
50 * It still kept in the example repository with the hope that it might be
51 * useful, and maybe some day someone who knows enough about boost::asio will
52 * read this text, accept the challenge and make the example code work
53 * correctly. Until then: expect this example program to fail occasionally.
54 * ===========================================================================
55 */
56
57
58 #include <curl/curl.h>
59 #include <boost/asio.hpp>
60 #include <boost/bind.hpp>
61 #include <iostream>
62
63 #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
64
65 /* boost::asio related objects
66 * using global variables for simplicity
67 */
68 boost::asio::io_service io_service;
69 boost::asio::deadline_timer timer(io_service);
70 std::map<curl_socket_t, boost::asio::ip::tcp::socket *> socket_map;
71
72 /* Global information, common to all connections */
73 typedef struct _GlobalInfo
74 {
75 CURLM *multi;
76 int still_running;
77 } GlobalInfo;
78
79 /* Information associated with a specific easy handle */
80 typedef struct _ConnInfo
81 {
82 CURL *easy;
83 char *url;
84 GlobalInfo *global;
85 char error[CURL_ERROR_SIZE];
86 } ConnInfo;
87
88 static void timer_cb(const boost::system::error_code & error, GlobalInfo *g);
89
90 /* Update the event timer after curl_multi library calls */
multi_timer_cb(CURLM * multi,long timeout_ms,GlobalInfo * g)91 static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
92 {
93 fprintf(MSG_OUT, "\nmulti_timer_cb: timeout_ms %ld", timeout_ms);
94
95 /* cancel running timer */
96 timer.cancel();
97
98 if(timeout_ms > 0) {
99 /* update timer */
100 timer.expires_from_now(boost::posix_time::millisec(timeout_ms));
101 timer.async_wait(boost::bind(&timer_cb, _1, g));
102 }
103 else if(timeout_ms == 0) {
104 /* call timeout function immediately */
105 boost::system::error_code error; /*success*/
106 timer_cb(error, g);
107 }
108
109 return 0;
110 }
111
112 /* Die if we get a bad CURLMcode somewhere */
mcode_or_die(const char * where,CURLMcode code)113 static void mcode_or_die(const char *where, CURLMcode code)
114 {
115 if(CURLM_OK != code) {
116 const char *s;
117 switch(code) {
118 case CURLM_CALL_MULTI_PERFORM:
119 s = "CURLM_CALL_MULTI_PERFORM";
120 break;
121 case CURLM_BAD_HANDLE:
122 s = "CURLM_BAD_HANDLE";
123 break;
124 case CURLM_BAD_EASY_HANDLE:
125 s = "CURLM_BAD_EASY_HANDLE";
126 break;
127 case CURLM_OUT_OF_MEMORY:
128 s = "CURLM_OUT_OF_MEMORY";
129 break;
130 case CURLM_INTERNAL_ERROR:
131 s = "CURLM_INTERNAL_ERROR";
132 break;
133 case CURLM_UNKNOWN_OPTION:
134 s = "CURLM_UNKNOWN_OPTION";
135 break;
136 case CURLM_LAST:
137 s = "CURLM_LAST";
138 break;
139 default:
140 s = "CURLM_unknown";
141 break;
142 case CURLM_BAD_SOCKET:
143 s = "CURLM_BAD_SOCKET";
144 fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
145 /* ignore this error */
146 return;
147 }
148
149 fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
150
151 exit(code);
152 }
153 }
154
155 /* Check for completed transfers, and remove their easy handles */
check_multi_info(GlobalInfo * g)156 static void check_multi_info(GlobalInfo *g)
157 {
158 char *eff_url;
159 CURLMsg *msg;
160 int msgs_left;
161 ConnInfo *conn;
162 CURL *easy;
163 CURLcode res;
164
165 fprintf(MSG_OUT, "\nREMAINING: %d", g->still_running);
166
167 while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
168 if(msg->msg == CURLMSG_DONE) {
169 easy = msg->easy_handle;
170 res = msg->data.result;
171 curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
172 curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
173 fprintf(MSG_OUT, "\nDONE: %s => (%d) %s", eff_url, res, conn->error);
174 curl_multi_remove_handle(g->multi, easy);
175 free(conn->url);
176 curl_easy_cleanup(easy);
177 free(conn);
178 }
179 }
180 }
181
182 /* Called by asio when there is an action on a socket */
event_cb(GlobalInfo * g,curl_socket_t s,int action,const boost::system::error_code & error,int * fdp)183 static void event_cb(GlobalInfo *g, curl_socket_t s,
184 int action, const boost::system::error_code & error,
185 int *fdp)
186 {
187 fprintf(MSG_OUT, "\nevent_cb: action=%d", action);
188
189 if(socket_map.find(s) == socket_map.end()) {
190 fprintf(MSG_OUT, "\nevent_cb: socket already closed");
191 return;
192 }
193
194 /* make sure the event matches what are wanted */
195 if(*fdp == action || *fdp == CURL_POLL_INOUT) {
196 CURLMcode rc;
197 if(error)
198 action = CURL_CSELECT_ERR;
199 rc = curl_multi_socket_action(g->multi, s, action, &g->still_running);
200
201 mcode_or_die("event_cb: curl_multi_socket_action", rc);
202 check_multi_info(g);
203
204 if(g->still_running <= 0) {
205 fprintf(MSG_OUT, "\nlast transfer done, kill timeout");
206 timer.cancel();
207 }
208
209 /* keep on watching.
210 * the socket may have been closed and/or fdp may have been changed
211 * in curl_multi_socket_action(), so check them both */
212 if(!error && socket_map.find(s) != socket_map.end() &&
213 (*fdp == action || *fdp == CURL_POLL_INOUT)) {
214 boost::asio::ip::tcp::socket *tcp_socket = socket_map.find(s)->second;
215
216 if(action == CURL_POLL_IN) {
217 tcp_socket->async_read_some(boost::asio::null_buffers(),
218 boost::bind(&event_cb, g, s,
219 action, _1, fdp));
220 }
221 if(action == CURL_POLL_OUT) {
222 tcp_socket->async_write_some(boost::asio::null_buffers(),
223 boost::bind(&event_cb, g, s,
224 action, _1, fdp));
225 }
226 }
227 }
228 }
229
230 /* Called by asio when our timeout expires */
timer_cb(const boost::system::error_code & error,GlobalInfo * g)231 static void timer_cb(const boost::system::error_code & error, GlobalInfo *g)
232 {
233 if(!error) {
234 fprintf(MSG_OUT, "\ntimer_cb: ");
235
236 CURLMcode rc;
237 rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0,
238 &g->still_running);
239
240 mcode_or_die("timer_cb: curl_multi_socket_action", rc);
241 check_multi_info(g);
242 }
243 }
244
245 /* Clean up any data */
remsock(int * f,GlobalInfo * g)246 static void remsock(int *f, GlobalInfo *g)
247 {
248 fprintf(MSG_OUT, "\nremsock: ");
249
250 if(f) {
251 free(f);
252 }
253 }
254
setsock(int * fdp,curl_socket_t s,CURL * e,int act,int oldact,GlobalInfo * g)255 static void setsock(int *fdp, curl_socket_t s, CURL *e, int act, int oldact,
256 GlobalInfo *g)
257 {
258 fprintf(MSG_OUT, "\nsetsock: socket=%d, act=%d, fdp=%p", s, act, fdp);
259
260 std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it =
261 socket_map.find(s);
262
263 if(it == socket_map.end()) {
264 fprintf(MSG_OUT, "\nsocket %d is a c-ares socket, ignoring", s);
265 return;
266 }
267
268 boost::asio::ip::tcp::socket * tcp_socket = it->second;
269
270 *fdp = act;
271
272 if(act == CURL_POLL_IN) {
273 fprintf(MSG_OUT, "\nwatching for socket to become readable");
274 if(oldact != CURL_POLL_IN && oldact != CURL_POLL_INOUT) {
275 tcp_socket->async_read_some(boost::asio::null_buffers(),
276 boost::bind(&event_cb, g, s,
277 CURL_POLL_IN, _1, fdp));
278 }
279 }
280 else if(act == CURL_POLL_OUT) {
281 fprintf(MSG_OUT, "\nwatching for socket to become writable");
282 if(oldact != CURL_POLL_OUT && oldact != CURL_POLL_INOUT) {
283 tcp_socket->async_write_some(boost::asio::null_buffers(),
284 boost::bind(&event_cb, g, s,
285 CURL_POLL_OUT, _1, fdp));
286 }
287 }
288 else if(act == CURL_POLL_INOUT) {
289 fprintf(MSG_OUT, "\nwatching for socket to become readable & writable");
290 if(oldact != CURL_POLL_IN && oldact != CURL_POLL_INOUT) {
291 tcp_socket->async_read_some(boost::asio::null_buffers(),
292 boost::bind(&event_cb, g, s,
293 CURL_POLL_IN, _1, fdp));
294 }
295 if(oldact != CURL_POLL_OUT && oldact != CURL_POLL_INOUT) {
296 tcp_socket->async_write_some(boost::asio::null_buffers(),
297 boost::bind(&event_cb, g, s,
298 CURL_POLL_OUT, _1, fdp));
299 }
300 }
301 }
302
addsock(curl_socket_t s,CURL * easy,int action,GlobalInfo * g)303 static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
304 {
305 /* fdp is used to store current action */
306 int *fdp = (int *) calloc(sizeof(int), 1);
307
308 setsock(fdp, s, easy, action, 0, g);
309 curl_multi_assign(g->multi, s, fdp);
310 }
311
312 /* CURLMOPT_SOCKETFUNCTION */
sock_cb(CURL * e,curl_socket_t s,int what,void * cbp,void * sockp)313 static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
314 {
315 fprintf(MSG_OUT, "\nsock_cb: socket=%d, what=%d, sockp=%p", s, what, sockp);
316
317 GlobalInfo *g = (GlobalInfo*) cbp;
318 int *actionp = (int *) sockp;
319 const char *whatstr[] = { "none", "IN", "OUT", "INOUT", "REMOVE"};
320
321 fprintf(MSG_OUT,
322 "\nsocket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
323
324 if(what == CURL_POLL_REMOVE) {
325 fprintf(MSG_OUT, "\n");
326 remsock(actionp, g);
327 }
328 else {
329 if(!actionp) {
330 fprintf(MSG_OUT, "\nAdding data: %s", whatstr[what]);
331 addsock(s, e, what, g);
332 }
333 else {
334 fprintf(MSG_OUT,
335 "\nChanging action from %s to %s",
336 whatstr[*actionp], whatstr[what]);
337 setsock(actionp, s, e, what, *actionp, g);
338 }
339 }
340
341 return 0;
342 }
343
344 /* CURLOPT_WRITEFUNCTION */
write_cb(void * ptr,size_t size,size_t nmemb,void * data)345 static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
346 {
347 size_t written = size * nmemb;
348 char *pBuffer = (char *)malloc(written + 1);
349
350 strncpy(pBuffer, (const char *)ptr, written);
351 pBuffer[written] = '\0';
352
353 fprintf(MSG_OUT, "%s", pBuffer);
354
355 free(pBuffer);
356
357 return written;
358 }
359
360 /* CURLOPT_PROGRESSFUNCTION */
prog_cb(void * p,double dltotal,double dlnow,double ult,double uln)361 static int prog_cb(void *p, double dltotal, double dlnow, double ult,
362 double uln)
363 {
364 ConnInfo *conn = (ConnInfo *)p;
365
366 (void)ult;
367 (void)uln;
368
369 fprintf(MSG_OUT, "\nProgress: %s (%g/%g)", conn->url, dlnow, dltotal);
370 fprintf(MSG_OUT, "\nProgress: %s (%g)", conn->url, ult);
371
372 return 0;
373 }
374
375 /* CURLOPT_OPENSOCKETFUNCTION */
opensocket(void * clientp,curlsocktype purpose,struct curl_sockaddr * address)376 static curl_socket_t opensocket(void *clientp, curlsocktype purpose,
377 struct curl_sockaddr *address)
378 {
379 fprintf(MSG_OUT, "\nopensocket :");
380
381 curl_socket_t sockfd = CURL_SOCKET_BAD;
382
383 /* restrict to IPv4 */
384 if(purpose == CURLSOCKTYPE_IPCXN && address->family == AF_INET) {
385 /* create a tcp socket object */
386 boost::asio::ip::tcp::socket *tcp_socket =
387 new boost::asio::ip::tcp::socket(io_service);
388
389 /* open it and get the native handle*/
390 boost::system::error_code ec;
391 tcp_socket->open(boost::asio::ip::tcp::v4(), ec);
392
393 if(ec) {
394 /* An error occurred */
395 std::cout << std::endl << "Couldn't open socket [" << ec << "][" <<
396 ec.message() << "]";
397 fprintf(MSG_OUT, "\nERROR: Returning CURL_SOCKET_BAD to signal error");
398 }
399 else {
400 sockfd = tcp_socket->native_handle();
401 fprintf(MSG_OUT, "\nOpened socket %d", sockfd);
402
403 /* save it for monitoring */
404 socket_map.insert(std::pair<curl_socket_t,
405 boost::asio::ip::tcp::socket *>(sockfd, tcp_socket));
406 }
407 }
408
409 return sockfd;
410 }
411
412 /* CURLOPT_CLOSESOCKETFUNCTION */
close_socket(void * clientp,curl_socket_t item)413 static int close_socket(void *clientp, curl_socket_t item)
414 {
415 fprintf(MSG_OUT, "\nclose_socket : %d", item);
416
417 std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it =
418 socket_map.find(item);
419
420 if(it != socket_map.end()) {
421 delete it->second;
422 socket_map.erase(it);
423 }
424
425 return 0;
426 }
427
428 /* Create a new easy handle, and add it to the global curl_multi */
new_conn(char * url,GlobalInfo * g)429 static void new_conn(char *url, GlobalInfo *g)
430 {
431 ConnInfo *conn;
432 CURLMcode rc;
433
434 conn = (ConnInfo *) calloc(1, sizeof(ConnInfo));
435
436 conn->easy = curl_easy_init();
437 if(!conn->easy) {
438 fprintf(MSG_OUT, "\ncurl_easy_init() failed, exiting!");
439 exit(2);
440 }
441
442 conn->global = g;
443 conn->url = strdup(url);
444 curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
445 curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
446 curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
447 curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
448 curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
449 curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
450 curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 1L);
451 curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
452 curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
453 curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
454 curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
455
456 /* call this function to get a socket */
457 curl_easy_setopt(conn->easy, CURLOPT_OPENSOCKETFUNCTION, opensocket);
458
459 /* call this function to close a socket */
460 curl_easy_setopt(conn->easy, CURLOPT_CLOSESOCKETFUNCTION, close_socket);
461
462 fprintf(MSG_OUT,
463 "\nAdding easy %p to multi %p (%s)", conn->easy, g->multi, url);
464 rc = curl_multi_add_handle(g->multi, conn->easy);
465 mcode_or_die("new_conn: curl_multi_add_handle", rc);
466
467 /* note that the add_handle() will set a time-out to trigger very soon so
468 that the necessary socket_action() call will be called by this app */
469 }
470
main(int argc,char ** argv)471 int main(int argc, char **argv)
472 {
473 GlobalInfo g;
474
475 (void)argc;
476 (void)argv;
477
478 memset(&g, 0, sizeof(GlobalInfo));
479 g.multi = curl_multi_init();
480
481 curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
482 curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
483 curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
484 curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
485
486 new_conn((char *)"www.google.com", &g); /* add a URL */
487
488 /* enter io_service run loop */
489 io_service.run();
490
491 curl_multi_cleanup(g.multi);
492
493 fprintf(MSG_OUT, "\ndone.\n");
494
495 return 0;
496 }
497