1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2019, 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 /* <DESC>
23 * multi socket API usage with libevent 2
24 * </DESC>
25 */
26 /* Example application source code using the multi socket interface to
27 download many files at once.
28
29 Written by Jeff Pohlmeyer
30
31 Requires libevent version 2 and a (POSIX?) system that has mkfifo().
32
33 This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c"
34 sample programs.
35
36 When running, the program creates the named pipe "hiper.fifo"
37
38 Whenever there is input into the fifo, the program reads the input as a list
39 of URL's and creates some new easy handles to fetch each URL via the
40 curl_multi "hiper" API.
41
42
43 Thus, you can try a single URL:
44 % echo http://www.yahoo.com > hiper.fifo
45
46 Or a whole bunch of them:
47 % cat my-url-list > hiper.fifo
48
49 The fifo buffer is handled almost instantly, so you can even add more URL's
50 while the previous requests are still being downloaded.
51
52 Note:
53 For the sake of simplicity, URL length is limited to 1023 char's !
54
55 This is purely a demo app, all retrieved data is simply discarded by the write
56 callback.
57
58 */
59
60 #include <stdio.h>
61 #include <string.h>
62 #include <stdlib.h>
63 #include <sys/time.h>
64 #include <time.h>
65 #include <unistd.h>
66 #include <sys/poll.h>
67 #include <curl/curl.h>
68 #include <event2/event.h>
69 #include <event2/event_struct.h>
70 #include <fcntl.h>
71 #include <sys/stat.h>
72 #include <errno.h>
73 #include <sys/cdefs.h>
74
75 #ifdef __GNUC__
76 #define _Unused __attribute__((unused))
77 #else
78 #define _Unused
79 #endif
80
81 #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
82
83
84 /* Global information, common to all connections */
85 typedef struct _GlobalInfo
86 {
87 struct event_base *evbase;
88 struct event fifo_event;
89 struct event timer_event;
90 CURLM *multi;
91 int still_running;
92 FILE *input;
93 int stopped;
94 } GlobalInfo;
95
96
97 /* Information associated with a specific easy handle */
98 typedef struct _ConnInfo
99 {
100 CURL *easy;
101 char *url;
102 GlobalInfo *global;
103 char error[CURL_ERROR_SIZE];
104 } ConnInfo;
105
106
107 /* Information associated with a specific socket */
108 typedef struct _SockInfo
109 {
110 curl_socket_t sockfd;
111 CURL *easy;
112 int action;
113 long timeout;
114 struct event ev;
115 GlobalInfo *global;
116 } SockInfo;
117
118 #define __case(code) \
119 case code: s = __STRING(code)
120
121 /* Die if we get a bad CURLMcode somewhere */
mcode_or_die(const char * where,CURLMcode code)122 static void mcode_or_die(const char *where, CURLMcode code)
123 {
124 if(CURLM_OK != code) {
125 const char *s;
126 switch(code) {
127 __case(CURLM_BAD_HANDLE); break;
128 __case(CURLM_BAD_EASY_HANDLE); break;
129 __case(CURLM_OUT_OF_MEMORY); break;
130 __case(CURLM_INTERNAL_ERROR); break;
131 __case(CURLM_UNKNOWN_OPTION); break;
132 __case(CURLM_LAST); break;
133 default: s = "CURLM_unknown"; break;
134 __case(CURLM_BAD_SOCKET);
135 fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
136 /* ignore this error */
137 return;
138 }
139 fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
140 exit(code);
141 }
142 }
143
144
145 /* Update the event timer after curl_multi library calls */
multi_timer_cb(CURLM * multi _Unused,long timeout_ms,GlobalInfo * g)146 static int multi_timer_cb(CURLM *multi _Unused, long timeout_ms, GlobalInfo *g)
147 {
148 struct timeval timeout;
149 CURLMcode rc;
150
151 timeout.tv_sec = timeout_ms/1000;
152 timeout.tv_usec = (timeout_ms%1000)*1000;
153 fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
154
155 /*
156 * if timeout_ms is -1, just delete the timer
157 *
158 * For all other values of timeout_ms, this should set or *update* the timer
159 * to the new value
160 */
161 if(timeout_ms == -1)
162 evtimer_del(&g->timer_event);
163 else /* includes timeout zero */
164 evtimer_add(&g->timer_event, &timeout);
165 return 0;
166 }
167
168
169 /* Check for completed transfers, and remove their easy handles */
check_multi_info(GlobalInfo * g)170 static void check_multi_info(GlobalInfo *g)
171 {
172 char *eff_url;
173 CURLMsg *msg;
174 int msgs_left;
175 ConnInfo *conn;
176 CURL *easy;
177 CURLcode res;
178
179 fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
180 while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
181 if(msg->msg == CURLMSG_DONE) {
182 easy = msg->easy_handle;
183 res = msg->data.result;
184 curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
185 curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
186 fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
187 curl_multi_remove_handle(g->multi, easy);
188 free(conn->url);
189 curl_easy_cleanup(easy);
190 free(conn);
191 }
192 }
193 if(g->still_running == 0 && g->stopped)
194 event_base_loopbreak(g->evbase);
195 }
196
197
198
199 /* Called by libevent when we get action on a multi socket */
event_cb(int fd,short kind,void * userp)200 static void event_cb(int fd, short kind, void *userp)
201 {
202 GlobalInfo *g = (GlobalInfo*) userp;
203 CURLMcode rc;
204
205 int action =
206 (kind & EV_READ ? CURL_CSELECT_IN : 0) |
207 (kind & EV_WRITE ? CURL_CSELECT_OUT : 0);
208
209 rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running);
210 mcode_or_die("event_cb: curl_multi_socket_action", rc);
211
212 check_multi_info(g);
213 if(g->still_running <= 0) {
214 fprintf(MSG_OUT, "last transfer done, kill timeout\n");
215 if(evtimer_pending(&g->timer_event, NULL)) {
216 evtimer_del(&g->timer_event);
217 }
218 }
219 }
220
221
222
223 /* Called by libevent when our timeout expires */
timer_cb(int fd _Unused,short kind _Unused,void * userp)224 static void timer_cb(int fd _Unused, short kind _Unused, void *userp)
225 {
226 GlobalInfo *g = (GlobalInfo *)userp;
227 CURLMcode rc;
228
229 rc = curl_multi_socket_action(g->multi,
230 CURL_SOCKET_TIMEOUT, 0, &g->still_running);
231 mcode_or_die("timer_cb: curl_multi_socket_action", rc);
232 check_multi_info(g);
233 }
234
235
236
237 /* Clean up the SockInfo structure */
remsock(SockInfo * f)238 static void remsock(SockInfo *f)
239 {
240 if(f) {
241 event_del(&f->ev);
242 free(f);
243 }
244 }
245
246
247
248 /* Assign information to a SockInfo structure */
setsock(SockInfo * f,curl_socket_t s,CURL * e,int act,GlobalInfo * g)249 static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act,
250 GlobalInfo *g)
251 {
252 int kind =
253 (act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0)|EV_PERSIST;
254
255 f->sockfd = s;
256 f->action = act;
257 f->easy = e;
258 event_del(&f->ev);
259 event_assign(&f->ev, g->evbase, f->sockfd, kind, event_cb, g);
260 event_add(&f->ev, NULL);
261 }
262
263
264
265 /* Initialize a new SockInfo structure */
addsock(curl_socket_t s,CURL * easy,int action,GlobalInfo * g)266 static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
267 {
268 SockInfo *fdp = calloc(sizeof(SockInfo), 1);
269
270 fdp->global = g;
271 setsock(fdp, s, easy, action, g);
272 curl_multi_assign(g->multi, s, fdp);
273 }
274
275 /* CURLMOPT_SOCKETFUNCTION */
sock_cb(CURL * e,curl_socket_t s,int what,void * cbp,void * sockp)276 static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
277 {
278 GlobalInfo *g = (GlobalInfo*) cbp;
279 SockInfo *fdp = (SockInfo*) sockp;
280 const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
281
282 fprintf(MSG_OUT,
283 "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
284 if(what == CURL_POLL_REMOVE) {
285 fprintf(MSG_OUT, "\n");
286 remsock(fdp);
287 }
288 else {
289 if(!fdp) {
290 fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
291 addsock(s, e, what, g);
292 }
293 else {
294 fprintf(MSG_OUT,
295 "Changing action from %s to %s\n",
296 whatstr[fdp->action], whatstr[what]);
297 setsock(fdp, s, e, what, g);
298 }
299 }
300 return 0;
301 }
302
303
304
305 /* CURLOPT_WRITEFUNCTION */
write_cb(void * ptr _Unused,size_t size,size_t nmemb,void * data)306 static size_t write_cb(void *ptr _Unused, size_t size, size_t nmemb,
307 void *data)
308 {
309 size_t realsize = size * nmemb;
310 ConnInfo *conn _Unused = (ConnInfo*) data;
311
312 return realsize;
313 }
314
315
316 /* CURLOPT_PROGRESSFUNCTION */
prog_cb(void * p,double dltotal,double dlnow,double ult _Unused,double uln _Unused)317 static int prog_cb(void *p, double dltotal, double dlnow, double ult _Unused,
318 double uln _Unused)
319 {
320 ConnInfo *conn = (ConnInfo *)p;
321
322 fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
323 return 0;
324 }
325
326
327 /* Create a new easy handle, and add it to the global curl_multi */
new_conn(char * url,GlobalInfo * g)328 static void new_conn(char *url, GlobalInfo *g)
329 {
330 ConnInfo *conn;
331 CURLMcode rc;
332
333 conn = calloc(1, sizeof(ConnInfo));
334 conn->error[0]='\0';
335
336 conn->easy = curl_easy_init();
337 if(!conn->easy) {
338 fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
339 exit(2);
340 }
341 conn->global = g;
342 conn->url = strdup(url);
343 curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
344 curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
345 curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
346 curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
347 curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
348 curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
349 curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
350 curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
351 curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
352 curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L);
353 fprintf(MSG_OUT,
354 "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
355 rc = curl_multi_add_handle(g->multi, conn->easy);
356 mcode_or_die("new_conn: curl_multi_add_handle", rc);
357
358 /* note that the add_handle() will set a time-out to trigger very soon so
359 that the necessary socket_action() call will be called by this app */
360 }
361
362 /* This gets called whenever data is received from the fifo */
fifo_cb(int fd _Unused,short event _Unused,void * arg)363 static void fifo_cb(int fd _Unused, short event _Unused, void *arg)
364 {
365 char s[1024];
366 long int rv = 0;
367 int n = 0;
368 GlobalInfo *g = (GlobalInfo *)arg;
369
370 do {
371 s[0]='\0';
372 rv = fscanf(g->input, "%1023s%n", s, &n);
373 s[n]='\0';
374 if(n && s[0]) {
375 if(!strcmp(s, "stop")) {
376 g->stopped = 1;
377 if(g->still_running == 0)
378 event_base_loopbreak(g->evbase);
379 }
380 else
381 new_conn(s, arg); /* if we read a URL, go get it! */
382 }
383 else
384 break;
385 } while(rv != EOF);
386 }
387
388 /* Create a named pipe and tell libevent to monitor it */
389 static const char *fifo = "hiper.fifo";
init_fifo(GlobalInfo * g)390 static int init_fifo(GlobalInfo *g)
391 {
392 struct stat st;
393 curl_socket_t sockfd;
394
395 fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
396 if(lstat (fifo, &st) == 0) {
397 if((st.st_mode & S_IFMT) == S_IFREG) {
398 errno = EEXIST;
399 perror("lstat");
400 exit(1);
401 }
402 }
403 unlink(fifo);
404 if(mkfifo (fifo, 0600) == -1) {
405 perror("mkfifo");
406 exit(1);
407 }
408 sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
409 if(sockfd == -1) {
410 perror("open");
411 exit(1);
412 }
413 g->input = fdopen(sockfd, "r");
414
415 fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
416 event_assign(&g->fifo_event, g->evbase, sockfd, EV_READ|EV_PERSIST,
417 fifo_cb, g);
418 event_add(&g->fifo_event, NULL);
419 return (0);
420 }
421
clean_fifo(GlobalInfo * g)422 static void clean_fifo(GlobalInfo *g)
423 {
424 event_del(&g->fifo_event);
425 fclose(g->input);
426 unlink(fifo);
427 }
428
main(int argc _Unused,char ** argv _Unused)429 int main(int argc _Unused, char **argv _Unused)
430 {
431 GlobalInfo g;
432
433 memset(&g, 0, sizeof(GlobalInfo));
434 g.evbase = event_base_new();
435 init_fifo(&g);
436 g.multi = curl_multi_init();
437 evtimer_assign(&g.timer_event, g.evbase, timer_cb, &g);
438
439 /* setup the generic multi interface options we want */
440 curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
441 curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
442 curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
443 curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
444
445 /* we don't call any curl_multi_socket*() function yet as we have no handles
446 added! */
447
448 event_base_dispatch(g.evbase);
449
450 /* this, of course, won't get called since only way to stop this program is
451 via ctrl-C, but it is here to show how cleanup /would/ be done. */
452 clean_fifo(&g);
453 event_del(&g.timer_event);
454 event_base_free(g.evbase);
455 curl_multi_cleanup(g.multi);
456 return 0;
457 }
458