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 epoll and timerfd
24 * </DESC>
25 */
26 /* Example application source code using the multi socket interface to
27 * download many files at once.
28 *
29 * This example features the same basic functionality as hiperfifo.c does,
30 * but this uses epoll and timerfd instead of libevent.
31 *
32 * Written by Jeff Pohlmeyer, converted to use epoll by Josh Bialkowski
33
34 Requires a linux system with epoll
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 <errno.h>
61 #include <fcntl.h>
62 #include <signal.h>
63 #include <stdio.h>
64 #include <stdlib.h>
65 #include <string.h>
66 #include <sys/epoll.h>
67 #include <sys/stat.h>
68 #include <sys/time.h>
69 #include <sys/timerfd.h>
70 #include <sys/types.h>
71 #include <time.h>
72 #include <unistd.h>
73
74 #include <curl/curl.h>
75
76 #ifdef __GNUC__
77 #define _Unused __attribute__((unused))
78 #else
79 #define _Unused
80 #endif
81
82 #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
83
84
85 /* Global information, common to all connections */
86 typedef struct _GlobalInfo
87 {
88 int epfd; /* epoll filedescriptor */
89 int tfd; /* timer filedescriptor */
90 int fifofd; /* fifo filedescriptor */
91 CURLM *multi;
92 int still_running;
93 FILE *input;
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 GlobalInfo *global;
115 } SockInfo;
116
117 #define __case(code) \
118 case code: s = __STRING(code)
119
120 /* Die if we get a bad CURLMcode somewhere */
mcode_or_die(const char * where,CURLMcode code)121 static void mcode_or_die(const char *where, CURLMcode code)
122 {
123 if(CURLM_OK != code) {
124 const char *s;
125 switch(code) {
126 __case(CURLM_BAD_HANDLE); break;
127 __case(CURLM_BAD_EASY_HANDLE); break;
128 __case(CURLM_OUT_OF_MEMORY); break;
129 __case(CURLM_INTERNAL_ERROR); break;
130 __case(CURLM_UNKNOWN_OPTION); break;
131 __case(CURLM_LAST); break;
132 default: s = "CURLM_unknown"; break;
133 __case(CURLM_BAD_SOCKET);
134 fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
135 /* ignore this error */
136 return;
137 }
138 fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
139 exit(code);
140 }
141 }
142
143 static void timer_cb(GlobalInfo* g, int revents);
144
145 /* Update the timer after curl_multi library does it's thing. Curl will
146 * inform us through this callback what it wants the new timeout to be,
147 * after it does some work. */
multi_timer_cb(CURLM * multi,long timeout_ms,GlobalInfo * g)148 static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
149 {
150 struct itimerspec its;
151 CURLMcode rc;
152
153 fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
154
155 if(timeout_ms > 0) {
156 its.it_interval.tv_sec = 1;
157 its.it_interval.tv_nsec = 0;
158 its.it_value.tv_sec = timeout_ms / 1000;
159 its.it_value.tv_nsec = (timeout_ms % 1000) * 1000 * 1000;
160 }
161 else if(timeout_ms == 0) {
162 /* libcurl wants us to timeout now, however setting both fields of
163 * new_value.it_value to zero disarms the timer. The closest we can
164 * do is to schedule the timer to fire in 1 ns. */
165 its.it_interval.tv_sec = 1;
166 its.it_interval.tv_nsec = 0;
167 its.it_value.tv_sec = 0;
168 its.it_value.tv_nsec = 1;
169 }
170 else {
171 memset(&its, 0, sizeof(struct itimerspec));
172 }
173
174 timerfd_settime(g->tfd, /*flags=*/0, &its, NULL);
175 return 0;
176 }
177
178
179 /* Check for completed transfers, and remove their easy handles */
check_multi_info(GlobalInfo * g)180 static void check_multi_info(GlobalInfo *g)
181 {
182 char *eff_url;
183 CURLMsg *msg;
184 int msgs_left;
185 ConnInfo *conn;
186 CURL *easy;
187 CURLcode res;
188
189 fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
190 while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
191 if(msg->msg == CURLMSG_DONE) {
192 easy = msg->easy_handle;
193 res = msg->data.result;
194 curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
195 curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
196 fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
197 curl_multi_remove_handle(g->multi, easy);
198 free(conn->url);
199 curl_easy_cleanup(easy);
200 free(conn);
201 }
202 }
203 }
204
205 /* Called by libevent when we get action on a multi socket filedescriptor*/
event_cb(GlobalInfo * g,int fd,int revents)206 static void event_cb(GlobalInfo *g, int fd, int revents)
207 {
208 CURLMcode rc;
209 struct itimerspec its;
210
211 int action = (revents & EPOLLIN ? CURL_CSELECT_IN : 0) |
212 (revents & EPOLLOUT ? CURL_CSELECT_OUT : 0);
213
214 rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running);
215 mcode_or_die("event_cb: curl_multi_socket_action", rc);
216
217 check_multi_info(g);
218 if(g->still_running <= 0) {
219 fprintf(MSG_OUT, "last transfer done, kill timeout\n");
220 memset(&its, 0, sizeof(struct itimerspec));
221 timerfd_settime(g->tfd, 0, &its, NULL);
222 }
223 }
224
225 /* Called by main loop when our timeout expires */
timer_cb(GlobalInfo * g,int revents)226 static void timer_cb(GlobalInfo* g, int revents)
227 {
228 CURLMcode rc;
229 uint64_t count = 0;
230 ssize_t err = 0;
231
232 err = read(g->tfd, &count, sizeof(uint64_t));
233 if(err == -1) {
234 /* Note that we may call the timer callback even if the timerfd isn't
235 * readable. It's possible that there are multiple events stored in the
236 * epoll buffer (i.e. the timer may have fired multiple times). The
237 * event count is cleared after the first call so future events in the
238 * epoll buffer will fail to read from the timer. */
239 if(errno == EAGAIN) {
240 fprintf(MSG_OUT, "EAGAIN on tfd %d\n", g->tfd);
241 return;
242 }
243 }
244 if(err != sizeof(uint64_t)) {
245 fprintf(stderr, "read(tfd) == %ld", err);
246 perror("read(tfd)");
247 }
248
249 rc = curl_multi_socket_action(g->multi,
250 CURL_SOCKET_TIMEOUT, 0, &g->still_running);
251 mcode_or_die("timer_cb: curl_multi_socket_action", rc);
252 check_multi_info(g);
253 }
254
255
256
257 /* Clean up the SockInfo structure */
remsock(SockInfo * f,GlobalInfo * g)258 static void remsock(SockInfo *f, GlobalInfo* g)
259 {
260 if(f) {
261 if(f->sockfd) {
262 if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL))
263 fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n",
264 f->sockfd, strerror(errno));
265 }
266 free(f);
267 }
268 }
269
270
271
272 /* Assign information to a SockInfo structure */
setsock(SockInfo * f,curl_socket_t s,CURL * e,int act,GlobalInfo * g)273 static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act,
274 GlobalInfo *g)
275 {
276 struct epoll_event ev;
277 int kind = (act & CURL_POLL_IN ? EPOLLIN : 0) |
278 (act & CURL_POLL_OUT ? EPOLLOUT : 0);
279
280 if(f->sockfd) {
281 if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL))
282 fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n",
283 f->sockfd, strerror(errno));
284 }
285
286 f->sockfd = s;
287 f->action = act;
288 f->easy = e;
289
290 ev.events = kind;
291 ev.data.fd = s;
292 if(epoll_ctl(g->epfd, EPOLL_CTL_ADD, s, &ev))
293 fprintf(stderr, "EPOLL_CTL_ADD failed for fd: %d : %s\n",
294 s, strerror(errno));
295 }
296
297
298
299 /* Initialize a new SockInfo structure */
addsock(curl_socket_t s,CURL * easy,int action,GlobalInfo * g)300 static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
301 {
302 SockInfo *fdp = (SockInfo*)calloc(sizeof(SockInfo), 1);
303
304 fdp->global = g;
305 setsock(fdp, s, easy, action, g);
306 curl_multi_assign(g->multi, s, fdp);
307 }
308
309 /* CURLMOPT_SOCKETFUNCTION */
sock_cb(CURL * e,curl_socket_t s,int what,void * cbp,void * sockp)310 static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
311 {
312 GlobalInfo *g = (GlobalInfo*) cbp;
313 SockInfo *fdp = (SockInfo*) sockp;
314 const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
315
316 fprintf(MSG_OUT,
317 "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
318 if(what == CURL_POLL_REMOVE) {
319 fprintf(MSG_OUT, "\n");
320 remsock(fdp, g);
321 }
322 else {
323 if(!fdp) {
324 fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
325 addsock(s, e, what, g);
326 }
327 else {
328 fprintf(MSG_OUT,
329 "Changing action from %s to %s\n",
330 whatstr[fdp->action], whatstr[what]);
331 setsock(fdp, s, e, what, g);
332 }
333 }
334 return 0;
335 }
336
337
338
339 /* CURLOPT_WRITEFUNCTION */
write_cb(void * ptr _Unused,size_t size,size_t nmemb,void * data)340 static size_t write_cb(void *ptr _Unused, size_t size, size_t nmemb,
341 void *data)
342 {
343 size_t realsize = size * nmemb;
344 ConnInfo *conn _Unused = (ConnInfo*) data;
345
346 return realsize;
347 }
348
349
350 /* CURLOPT_PROGRESSFUNCTION */
prog_cb(void * p,double dltotal,double dlnow,double ult _Unused,double uln _Unused)351 static int prog_cb(void *p, double dltotal, double dlnow, double ult _Unused,
352 double uln _Unused)
353 {
354 ConnInfo *conn = (ConnInfo *)p;
355
356 fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
357 return 0;
358 }
359
360
361 /* Create a new easy handle, and add it to the global curl_multi */
new_conn(char * url,GlobalInfo * g)362 static void new_conn(char *url, GlobalInfo *g)
363 {
364 ConnInfo *conn;
365 CURLMcode rc;
366
367 conn = (ConnInfo*)calloc(1, sizeof(ConnInfo));
368 conn->error[0]='\0';
369
370 conn->easy = curl_easy_init();
371 if(!conn->easy) {
372 fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
373 exit(2);
374 }
375 conn->global = g;
376 conn->url = strdup(url);
377 curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
378 curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
379 curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
380 curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
381 curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
382 curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
383 curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
384 curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
385 curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
386 curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L);
387 curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
388 curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
389 fprintf(MSG_OUT,
390 "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
391 rc = curl_multi_add_handle(g->multi, conn->easy);
392 mcode_or_die("new_conn: curl_multi_add_handle", rc);
393
394 /* note that the add_handle() will set a time-out to trigger very soon so
395 that the necessary socket_action() call will be called by this app */
396 }
397
398 /* This gets called whenever data is received from the fifo */
fifo_cb(GlobalInfo * g,int revents)399 static void fifo_cb(GlobalInfo* g, int revents)
400 {
401 char s[1024];
402 long int rv = 0;
403 int n = 0;
404
405 do {
406 s[0]='\0';
407 rv = fscanf(g->input, "%1023s%n", s, &n);
408 s[n]='\0';
409 if(n && s[0]) {
410 new_conn(s, g); /* if we read a URL, go get it! */
411 }
412 else
413 break;
414 } while(rv != EOF);
415 }
416
417 /* Create a named pipe and tell libevent to monitor it */
418 static const char *fifo = "hiper.fifo";
init_fifo(GlobalInfo * g)419 static int init_fifo(GlobalInfo *g)
420 {
421 struct stat st;
422 curl_socket_t sockfd;
423 struct epoll_event epev;
424
425 fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
426 if(lstat (fifo, &st) == 0) {
427 if((st.st_mode & S_IFMT) == S_IFREG) {
428 errno = EEXIST;
429 perror("lstat");
430 exit(1);
431 }
432 }
433 unlink(fifo);
434 if(mkfifo (fifo, 0600) == -1) {
435 perror("mkfifo");
436 exit(1);
437 }
438 sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
439 if(sockfd == -1) {
440 perror("open");
441 exit(1);
442 }
443
444 g->fifofd = sockfd;
445 g->input = fdopen(sockfd, "r");
446
447 epev.events = EPOLLIN;
448 epev.data.fd = sockfd;
449 epoll_ctl(g->epfd, EPOLL_CTL_ADD, sockfd, &epev);
450
451 fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
452 return 0;
453 }
454
clean_fifo(GlobalInfo * g)455 static void clean_fifo(GlobalInfo *g)
456 {
457 epoll_ctl(g->epfd, EPOLL_CTL_DEL, g->fifofd, NULL);
458 fclose(g->input);
459 unlink(fifo);
460 }
461
462
463 int g_should_exit_ = 0;
464
SignalHandler(int signo)465 void SignalHandler(int signo)
466 {
467 if(signo == SIGINT) {
468 g_should_exit_ = 1;
469 }
470 }
471
main(int argc _Unused,char ** argv _Unused)472 int main(int argc _Unused, char **argv _Unused)
473 {
474 GlobalInfo g;
475 int err;
476 int idx;
477 struct itimerspec its;
478 struct epoll_event ev;
479 struct epoll_event events[10];
480
481 g_should_exit_ = 0;
482 signal(SIGINT, SignalHandler);
483
484 memset(&g, 0, sizeof(GlobalInfo));
485 g.epfd = epoll_create1(EPOLL_CLOEXEC);
486 if(g.epfd == -1) {
487 perror("epoll_create1 failed");
488 exit(1);
489 }
490
491 g.tfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC);
492 if(g.tfd == -1) {
493 perror("timerfd_create failed");
494 exit(1);
495 }
496
497 memset(&its, 0, sizeof(struct itimerspec));
498 its.it_interval.tv_sec = 1;
499 its.it_value.tv_sec = 1;
500 timerfd_settime(g.tfd, 0, &its, NULL);
501
502 ev.events = EPOLLIN;
503 ev.data.fd = g.tfd;
504 epoll_ctl(g.epfd, EPOLL_CTL_ADD, g.tfd, &ev);
505
506 init_fifo(&g);
507 g.multi = curl_multi_init();
508
509 /* setup the generic multi interface options we want */
510 curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
511 curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
512 curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
513 curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
514
515 /* we don't call any curl_multi_socket*() function yet as we have no handles
516 added! */
517
518 fprintf(MSG_OUT, "Entering wait loop\n");
519 fflush(MSG_OUT);
520 while(!g_should_exit_) {
521 /* TODO(josh): use epoll_pwait to avoid a race on the signal. Mask the
522 * signal before the while loop, and then re-enable the signal during
523 * epoll wait. Mask at the end of the loop. */
524 err = epoll_wait(g.epfd, events, sizeof(events)/sizeof(struct epoll_event),
525 10000);
526 if(err == -1) {
527 if(errno == EINTR) {
528 fprintf(MSG_OUT, "note: wait interrupted\n");
529 continue;
530 }
531 else {
532 perror("epoll_wait");
533 exit(1);
534 }
535 }
536
537 for(idx = 0; idx < err; ++idx) {
538 if(events[idx].data.fd == g.fifofd) {
539 fifo_cb(&g, events[idx].events);
540 }
541 else if(events[idx].data.fd == g.tfd) {
542 timer_cb(&g, events[idx].events);
543 }
544 else {
545 event_cb(&g, events[idx].data.fd, events[idx].events);
546 }
547 }
548 }
549
550 fprintf(MSG_OUT, "Exiting normally.\n");
551 fflush(MSG_OUT);
552
553 curl_multi_cleanup(g.multi);
554 return 0;
555 }
556