Annotation of embedaddon/curl/docs/examples/ephiperfifo.c, revision 1.1.1.1
1.1 misho 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: #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
77:
78:
79: /* Global information, common to all connections */
80: typedef struct _GlobalInfo
81: {
82: int epfd; /* epoll filedescriptor */
83: int tfd; /* timer filedescriptor */
84: int fifofd; /* fifo filedescriptor */
85: CURLM *multi;
86: int still_running;
87: FILE *input;
88: } GlobalInfo;
89:
90:
91: /* Information associated with a specific easy handle */
92: typedef struct _ConnInfo
93: {
94: CURL *easy;
95: char *url;
96: GlobalInfo *global;
97: char error[CURL_ERROR_SIZE];
98: } ConnInfo;
99:
100:
101: /* Information associated with a specific socket */
102: typedef struct _SockInfo
103: {
104: curl_socket_t sockfd;
105: CURL *easy;
106: int action;
107: long timeout;
108: GlobalInfo *global;
109: } SockInfo;
110:
111: #define mycase(code) \
112: case code: s = __STRING(code)
113:
114: /* Die if we get a bad CURLMcode somewhere */
115: static void mcode_or_die(const char *where, CURLMcode code)
116: {
117: if(CURLM_OK != code) {
118: const char *s;
119: switch(code) {
120: mycase(CURLM_BAD_HANDLE); break;
121: mycase(CURLM_BAD_EASY_HANDLE); break;
122: mycase(CURLM_OUT_OF_MEMORY); break;
123: mycase(CURLM_INTERNAL_ERROR); break;
124: mycase(CURLM_UNKNOWN_OPTION); break;
125: mycase(CURLM_LAST); break;
126: default: s = "CURLM_unknown"; break;
127: mycase(CURLM_BAD_SOCKET);
128: fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
129: /* ignore this error */
130: return;
131: }
132: fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
133: exit(code);
134: }
135: }
136:
137: static void timer_cb(GlobalInfo* g, int revents);
138:
139: /* Update the timer after curl_multi library does it's thing. Curl will
140: * inform us through this callback what it wants the new timeout to be,
141: * after it does some work. */
142: static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
143: {
144: struct itimerspec its;
145:
146: fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
147:
148: if(timeout_ms > 0) {
149: its.it_interval.tv_sec = 1;
150: its.it_interval.tv_nsec = 0;
151: its.it_value.tv_sec = timeout_ms / 1000;
152: its.it_value.tv_nsec = (timeout_ms % 1000) * 1000 * 1000;
153: }
154: else if(timeout_ms == 0) {
155: /* libcurl wants us to timeout now, however setting both fields of
156: * new_value.it_value to zero disarms the timer. The closest we can
157: * do is to schedule the timer to fire in 1 ns. */
158: its.it_interval.tv_sec = 1;
159: its.it_interval.tv_nsec = 0;
160: its.it_value.tv_sec = 0;
161: its.it_value.tv_nsec = 1;
162: }
163: else {
164: memset(&its, 0, sizeof(struct itimerspec));
165: }
166:
167: timerfd_settime(g->tfd, /*flags=*/0, &its, NULL);
168: return 0;
169: }
170:
171:
172: /* Check for completed transfers, and remove their easy handles */
173: static void check_multi_info(GlobalInfo *g)
174: {
175: char *eff_url;
176: CURLMsg *msg;
177: int msgs_left;
178: ConnInfo *conn;
179: CURL *easy;
180: CURLcode res;
181:
182: fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
183: while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
184: if(msg->msg == CURLMSG_DONE) {
185: easy = msg->easy_handle;
186: res = msg->data.result;
187: curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
188: curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
189: fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
190: curl_multi_remove_handle(g->multi, easy);
191: free(conn->url);
192: curl_easy_cleanup(easy);
193: free(conn);
194: }
195: }
196: }
197:
198: /* Called by libevent when we get action on a multi socket filedescriptor*/
199: static void event_cb(GlobalInfo *g, int fd, int revents)
200: {
201: CURLMcode rc;
202: struct itimerspec its;
203:
204: int action = ((revents & EPOLLIN) ? CURL_CSELECT_IN : 0) |
205: ((revents & EPOLLOUT) ? CURL_CSELECT_OUT : 0);
206:
207: rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running);
208: mcode_or_die("event_cb: curl_multi_socket_action", rc);
209:
210: check_multi_info(g);
211: if(g->still_running <= 0) {
212: fprintf(MSG_OUT, "last transfer done, kill timeout\n");
213: memset(&its, 0, sizeof(struct itimerspec));
214: timerfd_settime(g->tfd, 0, &its, NULL);
215: }
216: }
217:
218: /* Called by main loop when our timeout expires */
219: static void timer_cb(GlobalInfo* g, int revents)
220: {
221: CURLMcode rc;
222: uint64_t count = 0;
223: ssize_t err = 0;
224:
225: err = read(g->tfd, &count, sizeof(uint64_t));
226: if(err == -1) {
227: /* Note that we may call the timer callback even if the timerfd isn't
228: * readable. It's possible that there are multiple events stored in the
229: * epoll buffer (i.e. the timer may have fired multiple times). The
230: * event count is cleared after the first call so future events in the
231: * epoll buffer will fail to read from the timer. */
232: if(errno == EAGAIN) {
233: fprintf(MSG_OUT, "EAGAIN on tfd %d\n", g->tfd);
234: return;
235: }
236: }
237: if(err != sizeof(uint64_t)) {
238: fprintf(stderr, "read(tfd) == %ld", err);
239: perror("read(tfd)");
240: }
241:
242: rc = curl_multi_socket_action(g->multi,
243: CURL_SOCKET_TIMEOUT, 0, &g->still_running);
244: mcode_or_die("timer_cb: curl_multi_socket_action", rc);
245: check_multi_info(g);
246: }
247:
248:
249:
250: /* Clean up the SockInfo structure */
251: static void remsock(SockInfo *f, GlobalInfo* g)
252: {
253: if(f) {
254: if(f->sockfd) {
255: if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL))
256: fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n",
257: f->sockfd, strerror(errno));
258: }
259: free(f);
260: }
261: }
262:
263:
264:
265: /* Assign information to a SockInfo structure */
266: static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act,
267: GlobalInfo *g)
268: {
269: struct epoll_event ev;
270: int kind = ((act & CURL_POLL_IN) ? EPOLLIN : 0) |
271: ((act & CURL_POLL_OUT) ? EPOLLOUT : 0);
272:
273: if(f->sockfd) {
274: if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL))
275: fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n",
276: f->sockfd, strerror(errno));
277: }
278:
279: f->sockfd = s;
280: f->action = act;
281: f->easy = e;
282:
283: ev.events = kind;
284: ev.data.fd = s;
285: if(epoll_ctl(g->epfd, EPOLL_CTL_ADD, s, &ev))
286: fprintf(stderr, "EPOLL_CTL_ADD failed for fd: %d : %s\n",
287: s, strerror(errno));
288: }
289:
290:
291:
292: /* Initialize a new SockInfo structure */
293: static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
294: {
295: SockInfo *fdp = (SockInfo*)calloc(sizeof(SockInfo), 1);
296:
297: fdp->global = g;
298: setsock(fdp, s, easy, action, 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: GlobalInfo *g = (GlobalInfo*) cbp;
306: SockInfo *fdp = (SockInfo*) sockp;
307: const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
308:
309: fprintf(MSG_OUT,
310: "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
311: if(what == CURL_POLL_REMOVE) {
312: fprintf(MSG_OUT, "\n");
313: remsock(fdp, g);
314: }
315: else {
316: if(!fdp) {
317: fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
318: addsock(s, e, what, g);
319: }
320: else {
321: fprintf(MSG_OUT,
322: "Changing action from %s to %s\n",
323: whatstr[fdp->action], whatstr[what]);
324: setsock(fdp, s, e, what, g);
325: }
326: }
327: return 0;
328: }
329:
330:
331:
332: /* CURLOPT_WRITEFUNCTION */
333: static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
334: {
335: (void)ptr;
336: (void)data;
337: return size * nmemb;
338: }
339:
340:
341: /* CURLOPT_PROGRESSFUNCTION */
342: static int prog_cb(void *p, double dltotal, double dlnow, double ult,
343: double uln)
344: {
345: ConnInfo *conn = (ConnInfo *)p;
346: (void)ult;
347: (void)uln;
348:
349: fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
350: return 0;
351: }
352:
353:
354: /* Create a new easy handle, and add it to the global curl_multi */
355: static void new_conn(char *url, GlobalInfo *g)
356: {
357: ConnInfo *conn;
358: CURLMcode rc;
359:
360: conn = (ConnInfo*)calloc(1, sizeof(ConnInfo));
361: conn->error[0]='\0';
362:
363: conn->easy = curl_easy_init();
364: if(!conn->easy) {
365: fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
366: exit(2);
367: }
368: conn->global = g;
369: conn->url = strdup(url);
370: curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
371: curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
372: curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
373: curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
374: curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
375: curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
376: curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
377: curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
378: curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
379: curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L);
380: curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
381: curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
382: fprintf(MSG_OUT,
383: "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
384: rc = curl_multi_add_handle(g->multi, conn->easy);
385: mcode_or_die("new_conn: curl_multi_add_handle", rc);
386:
387: /* note that the add_handle() will set a time-out to trigger very soon so
388: that the necessary socket_action() call will be called by this app */
389: }
390:
391: /* This gets called whenever data is received from the fifo */
392: static void fifo_cb(GlobalInfo* g, int revents)
393: {
394: char s[1024];
395: long int rv = 0;
396: int n = 0;
397:
398: do {
399: s[0]='\0';
400: rv = fscanf(g->input, "%1023s%n", s, &n);
401: s[n]='\0';
402: if(n && s[0]) {
403: new_conn(s, g); /* if we read a URL, go get it! */
404: }
405: else
406: break;
407: } while(rv != EOF);
408: }
409:
410: /* Create a named pipe and tell libevent to monitor it */
411: static const char *fifo = "hiper.fifo";
412: static int init_fifo(GlobalInfo *g)
413: {
414: struct stat st;
415: curl_socket_t sockfd;
416: struct epoll_event epev;
417:
418: fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
419: if(lstat (fifo, &st) == 0) {
420: if((st.st_mode & S_IFMT) == S_IFREG) {
421: errno = EEXIST;
422: perror("lstat");
423: exit(1);
424: }
425: }
426: unlink(fifo);
427: if(mkfifo (fifo, 0600) == -1) {
428: perror("mkfifo");
429: exit(1);
430: }
431: sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
432: if(sockfd == -1) {
433: perror("open");
434: exit(1);
435: }
436:
437: g->fifofd = sockfd;
438: g->input = fdopen(sockfd, "r");
439:
440: epev.events = EPOLLIN;
441: epev.data.fd = sockfd;
442: epoll_ctl(g->epfd, EPOLL_CTL_ADD, sockfd, &epev);
443:
444: fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
445: return 0;
446: }
447:
448: static void clean_fifo(GlobalInfo *g)
449: {
450: epoll_ctl(g->epfd, EPOLL_CTL_DEL, g->fifofd, NULL);
451: fclose(g->input);
452: unlink(fifo);
453: }
454:
455:
456: int g_should_exit_ = 0;
457:
458: void SignalHandler(int signo)
459: {
460: if(signo == SIGINT) {
461: g_should_exit_ = 1;
462: }
463: }
464:
465: int main(int argc, char **argv)
466: {
467: GlobalInfo g;
468: struct itimerspec its;
469: struct epoll_event ev;
470: struct epoll_event events[10];
471: (void)argc;
472: (void)argv;
473:
474: g_should_exit_ = 0;
475: signal(SIGINT, SignalHandler);
476:
477: memset(&g, 0, sizeof(GlobalInfo));
478: g.epfd = epoll_create1(EPOLL_CLOEXEC);
479: if(g.epfd == -1) {
480: perror("epoll_create1 failed");
481: exit(1);
482: }
483:
484: g.tfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC);
485: if(g.tfd == -1) {
486: perror("timerfd_create failed");
487: exit(1);
488: }
489:
490: memset(&its, 0, sizeof(struct itimerspec));
491: its.it_interval.tv_sec = 1;
492: its.it_value.tv_sec = 1;
493: timerfd_settime(g.tfd, 0, &its, NULL);
494:
495: ev.events = EPOLLIN;
496: ev.data.fd = g.tfd;
497: epoll_ctl(g.epfd, EPOLL_CTL_ADD, g.tfd, &ev);
498:
499: init_fifo(&g);
500: g.multi = curl_multi_init();
501:
502: /* setup the generic multi interface options we want */
503: curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
504: curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
505: curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
506: curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
507:
508: /* we don't call any curl_multi_socket*() function yet as we have no handles
509: added! */
510:
511: fprintf(MSG_OUT, "Entering wait loop\n");
512: fflush(MSG_OUT);
513: while(!g_should_exit_) {
514: int idx;
515: int err = epoll_wait(g.epfd, events,
516: sizeof(events)/sizeof(struct epoll_event), 10000);
517: if(err == -1) {
518: if(errno == EINTR) {
519: fprintf(MSG_OUT, "note: wait interrupted\n");
520: continue;
521: }
522: else {
523: perror("epoll_wait");
524: exit(1);
525: }
526: }
527:
528: for(idx = 0; idx < err; ++idx) {
529: if(events[idx].data.fd == g.fifofd) {
530: fifo_cb(&g, events[idx].events);
531: }
532: else if(events[idx].data.fd == g.tfd) {
533: timer_cb(&g, events[idx].events);
534: }
535: else {
536: event_cb(&g, events[idx].data.fd, events[idx].events);
537: }
538: }
539: }
540:
541: fprintf(MSG_OUT, "Exiting normally.\n");
542: fflush(MSG_OUT);
543:
544: curl_multi_cleanup(g.multi);
545: clean_fifo(&g);
546: return 0;
547: }
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