1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 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.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 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24/* <DESC>
25 * multi socket API usage with epoll and timerfd
26 * </DESC>
27 */
28/* Example application source code using the multi socket interface to
29 * download many files at once.
30 *
31 * This example features the same basic functionality as hiperfifo.c does,
32 * but this uses epoll and timerfd instead of libevent.
33 *
34 * Written by Jeff Pohlmeyer, converted to use epoll by Josh Bialkowski
35
36Requires a linux system with epoll
37
38When running, the program creates the named pipe "hiper.fifo"
39
40Whenever there is input into the fifo, the program reads the input as a list
41of URL's and creates some new easy handles to fetch each URL via the
42curl_multi "hiper" API.
43
44
45Thus, you can try a single URL:
46  % echo http://www.yahoo.com > hiper.fifo
47
48Or a whole bunch of them:
49  % cat my-url-list > hiper.fifo
50
51The fifo buffer is handled almost instantly, so you can even add more URL's
52while the previous requests are still being downloaded.
53
54Note:
55  For the sake of simplicity, URL length is limited to 1023 char's !
56
57This is purely a demo app, all retrieved data is simply discarded by the write
58callback.
59
60*/
61
62#include <errno.h>
63#include <fcntl.h>
64#include <signal.h>
65#include <stdio.h>
66#include <stdlib.h>
67#include <string.h>
68#include <sys/epoll.h>
69#include <sys/stat.h>
70#include <sys/time.h>
71#include <sys/timerfd.h>
72#include <sys/types.h>
73#include <time.h>
74#include <unistd.h>
75
76#include <curl/curl.h>
77
78#define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
79
80
81/* Global information, common to all connections */
82typedef struct _GlobalInfo
83{
84  int epfd;    /* epoll filedescriptor */
85  int tfd;     /* timer filedescriptor */
86  int fifofd;  /* fifo filedescriptor */
87  CURLM *multi;
88  int still_running;
89  FILE *input;
90} GlobalInfo;
91
92
93/* Information associated with a specific easy handle */
94typedef struct _ConnInfo
95{
96  CURL *easy;
97  char *url;
98  GlobalInfo *global;
99  char error[CURL_ERROR_SIZE];
100} ConnInfo;
101
102
103/* Information associated with a specific socket */
104typedef struct _SockInfo
105{
106  curl_socket_t sockfd;
107  CURL *easy;
108  int action;
109  long timeout;
110  GlobalInfo *global;
111} SockInfo;
112
113#define mycase(code) \
114  case code: s = __STRING(code)
115
116/* Die if we get a bad CURLMcode somewhere */
117static void mcode_or_die(const char *where, CURLMcode code)
118{
119  if(CURLM_OK != code) {
120    const char *s;
121    switch(code) {
122      mycase(CURLM_BAD_HANDLE); break;
123      mycase(CURLM_BAD_EASY_HANDLE); break;
124      mycase(CURLM_OUT_OF_MEMORY); break;
125      mycase(CURLM_INTERNAL_ERROR); break;
126      mycase(CURLM_UNKNOWN_OPTION); break;
127      mycase(CURLM_LAST); break;
128      default: s = "CURLM_unknown"; break;
129      mycase(CURLM_BAD_SOCKET);
130      fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
131      /* ignore this error */
132      return;
133    }
134    fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
135    exit(code);
136  }
137}
138
139static void timer_cb(GlobalInfo* g, int revents);
140
141/* Update the timer after curl_multi library does it's thing. Curl will
142 * inform us through this callback what it wants the new timeout to be,
143 * after it does some work. */
144static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
145{
146  struct itimerspec its;
147
148  fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
149
150  if(timeout_ms > 0) {
151    its.it_interval.tv_sec = 0;
152    its.it_interval.tv_nsec = 0;
153    its.it_value.tv_sec = timeout_ms / 1000;
154    its.it_value.tv_nsec = (timeout_ms % 1000) * 1000 * 1000;
155  }
156  else if(timeout_ms == 0) {
157    /* libcurl wants us to timeout now, however setting both fields of
158     * new_value.it_value to zero disarms the timer. The closest we can
159     * do is to schedule the timer to fire in 1 ns. */
160    its.it_interval.tv_sec = 0;
161    its.it_interval.tv_nsec = 0;
162    its.it_value.tv_sec = 0;
163    its.it_value.tv_nsec = 1;
164  }
165  else {
166    memset(&its, 0, sizeof(struct itimerspec));
167  }
168
169  timerfd_settime(g->tfd, /* flags= */0, &its, NULL);
170  return 0;
171}
172
173
174/* Check for completed transfers, and remove their easy handles */
175static void check_multi_info(GlobalInfo *g)
176{
177  char *eff_url;
178  CURLMsg *msg;
179  int msgs_left;
180  ConnInfo *conn;
181  CURL *easy;
182  CURLcode res;
183
184  fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
185  while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
186    if(msg->msg == CURLMSG_DONE) {
187      easy = msg->easy_handle;
188      res = msg->data.result;
189      curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
190      curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
191      fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
192      curl_multi_remove_handle(g->multi, easy);
193      free(conn->url);
194      curl_easy_cleanup(easy);
195      free(conn);
196    }
197  }
198}
199
200/* Called by libevent when we get action on a multi socket filedescriptor */
201static void event_cb(GlobalInfo *g, int fd, int revents)
202{
203  CURLMcode rc;
204  struct itimerspec its;
205
206  int action = ((revents & EPOLLIN) ? CURL_CSELECT_IN : 0) |
207               ((revents & EPOLLOUT) ? 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    memset(&its, 0, sizeof(struct itimerspec));
216    timerfd_settime(g->tfd, 0, &its, NULL);
217  }
218}
219
220/* Called by main loop when our timeout expires */
221static void timer_cb(GlobalInfo* g, int revents)
222{
223  CURLMcode rc;
224  uint64_t count = 0;
225  ssize_t err = 0;
226
227  err = read(g->tfd, &count, sizeof(uint64_t));
228  if(err == -1) {
229    /* Note that we may call the timer callback even if the timerfd is not
230     * readable. It's possible that there are multiple events stored in the
231     * epoll buffer (i.e. the timer may have fired multiple times). The
232     * event count is cleared after the first call so future events in the
233     * epoll buffer will fail to read from the timer. */
234    if(errno == EAGAIN) {
235      fprintf(MSG_OUT, "EAGAIN on tfd %d\n", g->tfd);
236      return;
237    }
238  }
239  if(err != sizeof(uint64_t)) {
240    fprintf(stderr, "read(tfd) == %ld", err);
241    perror("read(tfd)");
242  }
243
244  rc = curl_multi_socket_action(g->multi,
245                                  CURL_SOCKET_TIMEOUT, 0, &g->still_running);
246  mcode_or_die("timer_cb: curl_multi_socket_action", rc);
247  check_multi_info(g);
248}
249
250
251
252/* Clean up the SockInfo structure */
253static void remsock(SockInfo *f, GlobalInfo* g)
254{
255  if(f) {
256    if(f->sockfd) {
257      if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL))
258        fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n",
259                f->sockfd, strerror(errno));
260    }
261    free(f);
262  }
263}
264
265
266
267/* Assign information to a SockInfo structure */
268static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act,
269                    GlobalInfo *g)
270{
271  struct epoll_event ev;
272  int kind = ((act & CURL_POLL_IN) ? EPOLLIN : 0) |
273             ((act & CURL_POLL_OUT) ? EPOLLOUT : 0);
274
275  if(f->sockfd) {
276    if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL))
277      fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n",
278              f->sockfd, strerror(errno));
279  }
280
281  f->sockfd = s;
282  f->action = act;
283  f->easy = e;
284
285  ev.events = kind;
286  ev.data.fd = s;
287  if(epoll_ctl(g->epfd, EPOLL_CTL_ADD, s, &ev))
288    fprintf(stderr, "EPOLL_CTL_ADD failed for fd: %d : %s\n",
289            s, strerror(errno));
290}
291
292
293
294/* Initialize a new SockInfo structure */
295static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
296{
297  SockInfo *fdp = (SockInfo*)calloc(1, sizeof(SockInfo));
298
299  fdp->global = g;
300  setsock(fdp, s, easy, action, g);
301  curl_multi_assign(g->multi, s, fdp);
302}
303
304/* CURLMOPT_SOCKETFUNCTION */
305static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
306{
307  GlobalInfo *g = (GlobalInfo*) cbp;
308  SockInfo *fdp = (SockInfo*) sockp;
309  const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
310
311  fprintf(MSG_OUT,
312          "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
313  if(what == CURL_POLL_REMOVE) {
314    fprintf(MSG_OUT, "\n");
315    remsock(fdp, g);
316  }
317  else {
318    if(!fdp) {
319      fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
320      addsock(s, e, what, g);
321    }
322    else {
323      fprintf(MSG_OUT,
324              "Changing action from %s to %s\n",
325              whatstr[fdp->action], whatstr[what]);
326      setsock(fdp, s, e, what, g);
327    }
328  }
329  return 0;
330}
331
332
333
334/* CURLOPT_WRITEFUNCTION */
335static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
336{
337  (void)ptr;
338  (void)data;
339  return size * nmemb;
340}
341
342
343/* CURLOPT_PROGRESSFUNCTION */
344static int prog_cb(void *p, double dltotal, double dlnow, double ult,
345                   double uln)
346{
347  ConnInfo *conn = (ConnInfo *)p;
348  (void)ult;
349  (void)uln;
350
351  fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
352  return 0;
353}
354
355
356/* Create a new easy handle, and add it to the global curl_multi */
357static void new_conn(char *url, GlobalInfo *g)
358{
359  ConnInfo *conn;
360  CURLMcode rc;
361
362  conn = (ConnInfo*)calloc(1, sizeof(ConnInfo));
363  conn->error[0]='\0';
364
365  conn->easy = curl_easy_init();
366  if(!conn->easy) {
367    fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
368    exit(2);
369  }
370  conn->global = g;
371  conn->url = strdup(url);
372  curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
373  curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
374  curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
375  curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
376  curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
377  curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
378  curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
379  curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
380  curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
381  curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L);
382  curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
383  curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
384  fprintf(MSG_OUT,
385          "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
386  rc = curl_multi_add_handle(g->multi, conn->easy);
387  mcode_or_die("new_conn: curl_multi_add_handle", rc);
388
389  /* note that the add_handle() will set a time-out to trigger soon so that
390     the necessary socket_action() call will be called by this app */
391}
392
393/* This gets called whenever data is received from the fifo */
394static void fifo_cb(GlobalInfo* g, int revents)
395{
396  char s[1024];
397  long int rv = 0;
398  int n = 0;
399
400  do {
401    s[0]='\0';
402    rv = fscanf(g->input, "%1023s%n", s, &n);
403    s[n]='\0';
404    if(n && s[0]) {
405      new_conn(s, g); /* if we read a URL, go get it! */
406    }
407    else
408      break;
409  } while(rv != EOF);
410}
411
412/* Create a named pipe and tell libevent to monitor it */
413static const char *fifo = "hiper.fifo";
414static int init_fifo(GlobalInfo *g)
415{
416  struct stat st;
417  curl_socket_t sockfd;
418  struct epoll_event epev;
419
420  fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
421  if(lstat (fifo, &st) == 0) {
422    if((st.st_mode & S_IFMT) == S_IFREG) {
423      errno = EEXIST;
424      perror("lstat");
425      exit(1);
426    }
427  }
428  unlink(fifo);
429  if(mkfifo (fifo, 0600) == -1) {
430    perror("mkfifo");
431    exit(1);
432  }
433  sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
434  if(sockfd == -1) {
435    perror("open");
436    exit(1);
437  }
438
439  g->fifofd = sockfd;
440  g->input = fdopen(sockfd, "r");
441
442  epev.events = EPOLLIN;
443  epev.data.fd = sockfd;
444  epoll_ctl(g->epfd, EPOLL_CTL_ADD, sockfd, &epev);
445
446  fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
447  return 0;
448}
449
450static void clean_fifo(GlobalInfo *g)
451{
452    epoll_ctl(g->epfd, EPOLL_CTL_DEL, g->fifofd, NULL);
453    fclose(g->input);
454    unlink(fifo);
455}
456
457
458int g_should_exit_ = 0;
459
460void sigint_handler(int signo)
461{
462  g_should_exit_ = 1;
463}
464
465int 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, sigint_handler);
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 = 0;
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 do not 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}
548