1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2016, 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
29Written by Jeff Pohlmeyer
30
31Requires libevent version 2 and a (POSIX?) system that has mkfifo().
32
33This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c"
34sample programs.
35
36When running, the program creates the named pipe "hiper.fifo"
37
38Whenever there is input into the fifo, the program reads the input as a list
39of URL's and creates some new easy handles to fetch each URL via the
40curl_multi "hiper" API.
41
42
43Thus, you can try a single URL:
44  % echo http://www.yahoo.com > hiper.fifo
45
46Or a whole bunch of them:
47  % cat my-url-list > hiper.fifo
48
49The fifo buffer is handled almost instantly, so you can even add more URL's
50while the previous requests are still being downloaded.
51
52Note:
53  For the sake of simplicity, URL length is limited to 1023 char's !
54
55This is purely a demo app, all retrieved data is simply discarded by the write
56callback.
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 <fcntl.h>
70#include <sys/stat.h>
71#include <errno.h>
72
73
74#define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
75
76
77/* Global information, common to all connections */
78typedef struct _GlobalInfo
79{
80  struct event_base *evbase;
81  struct event *fifo_event;
82  struct event *timer_event;
83  CURLM *multi;
84  int still_running;
85  FILE* input;
86} GlobalInfo;
87
88
89/* Information associated with a specific easy handle */
90typedef struct _ConnInfo
91{
92  CURL *easy;
93  char *url;
94  GlobalInfo *global;
95  char error[CURL_ERROR_SIZE];
96} ConnInfo;
97
98
99/* Information associated with a specific socket */
100typedef struct _SockInfo
101{
102  curl_socket_t sockfd;
103  CURL *easy;
104  int action;
105  long timeout;
106  struct event *ev;
107  int evset;
108  GlobalInfo *global;
109} SockInfo;
110
111
112
113/* Update the event timer after curl_multi library calls */
114static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
115{
116  struct timeval timeout;
117  (void)multi; /* unused */
118
119  timeout.tv_sec = timeout_ms/1000;
120  timeout.tv_usec = (timeout_ms%1000)*1000;
121  fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
122  evtimer_add(g->timer_event, &timeout);
123  return 0;
124}
125
126/* Die if we get a bad CURLMcode somewhere */
127static void mcode_or_die(const char *where, CURLMcode code)
128{
129  if(CURLM_OK != code) {
130    const char *s;
131    switch (code) {
132      case     CURLM_BAD_HANDLE:         s="CURLM_BAD_HANDLE";         break;
133      case     CURLM_BAD_EASY_HANDLE:    s="CURLM_BAD_EASY_HANDLE";    break;
134      case     CURLM_OUT_OF_MEMORY:      s="CURLM_OUT_OF_MEMORY";      break;
135      case     CURLM_INTERNAL_ERROR:     s="CURLM_INTERNAL_ERROR";     break;
136      case     CURLM_UNKNOWN_OPTION:     s="CURLM_UNKNOWN_OPTION";     break;
137      case     CURLM_LAST:               s="CURLM_LAST";               break;
138      default: s="CURLM_unknown";
139        break;
140    case     CURLM_BAD_SOCKET:         s="CURLM_BAD_SOCKET";
141      fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
142      /* ignore this error */
143      return;
144    }
145    fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
146    exit(code);
147  }
148}
149
150
151
152/* Check for completed transfers, and remove their easy handles */
153static void check_multi_info(GlobalInfo *g)
154{
155  char *eff_url;
156  CURLMsg *msg;
157  int msgs_left;
158  ConnInfo *conn;
159  CURL *easy;
160  CURLcode res;
161
162  fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
163  while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
164    if(msg->msg == CURLMSG_DONE) {
165      easy = msg->easy_handle;
166      res = msg->data.result;
167      curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
168      curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
169      fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
170      curl_multi_remove_handle(g->multi, easy);
171      free(conn->url);
172      curl_easy_cleanup(easy);
173      free(conn);
174    }
175  }
176}
177
178
179
180/* Called by libevent when we get action on a multi socket */
181static void event_cb(int fd, short kind, void *userp)
182{
183  GlobalInfo *g = (GlobalInfo*) userp;
184  CURLMcode rc;
185
186  int action =
187    (kind & EV_READ ? CURL_CSELECT_IN : 0) |
188    (kind & EV_WRITE ? CURL_CSELECT_OUT : 0);
189
190  rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running);
191  mcode_or_die("event_cb: curl_multi_socket_action", rc);
192
193  check_multi_info(g);
194  if(g->still_running <= 0) {
195    fprintf(MSG_OUT, "last transfer done, kill timeout\n");
196    if(evtimer_pending(g->timer_event, NULL)) {
197      evtimer_del(g->timer_event);
198    }
199  }
200}
201
202
203
204/* Called by libevent when our timeout expires */
205static void timer_cb(int fd, short kind, void *userp)
206{
207  GlobalInfo *g = (GlobalInfo *)userp;
208  CURLMcode rc;
209  (void)fd;
210  (void)kind;
211
212  rc = curl_multi_socket_action(g->multi,
213                                  CURL_SOCKET_TIMEOUT, 0, &g->still_running);
214  mcode_or_die("timer_cb: curl_multi_socket_action", rc);
215  check_multi_info(g);
216}
217
218
219
220/* Clean up the SockInfo structure */
221static void remsock(SockInfo *f)
222{
223  if(f) {
224    if(f->evset)
225      event_free(f->ev);
226    free(f);
227  }
228}
229
230
231
232/* Assign information to a SockInfo structure */
233static void setsock(SockInfo*f, curl_socket_t s, CURL*e, int act, GlobalInfo*g)
234{
235  int kind =
236     (act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0)|EV_PERSIST;
237
238  f->sockfd = s;
239  f->action = act;
240  f->easy = e;
241  if(f->evset)
242    event_free(f->ev);
243  f->ev = event_new(g->evbase, f->sockfd, kind, event_cb, g);
244  f->evset = 1;
245  event_add(f->ev, NULL);
246}
247
248
249
250/* Initialize a new SockInfo structure */
251static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
252{
253  SockInfo *fdp = calloc(sizeof(SockInfo), 1);
254
255  fdp->global = g;
256  setsock(fdp, s, easy, action, g);
257  curl_multi_assign(g->multi, s, fdp);
258}
259
260/* CURLMOPT_SOCKETFUNCTION */
261static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
262{
263  GlobalInfo *g = (GlobalInfo*) cbp;
264  SockInfo *fdp = (SockInfo*) sockp;
265  const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
266
267  fprintf(MSG_OUT,
268          "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
269  if(what == CURL_POLL_REMOVE) {
270    fprintf(MSG_OUT, "\n");
271    remsock(fdp);
272  }
273  else {
274    if(!fdp) {
275      fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
276      addsock(s, e, what, g);
277    }
278    else {
279      fprintf(MSG_OUT,
280              "Changing action from %s to %s\n",
281              whatstr[fdp->action], whatstr[what]);
282      setsock(fdp, s, e, what, g);
283    }
284  }
285  return 0;
286}
287
288
289
290/* CURLOPT_WRITEFUNCTION */
291static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
292{
293  size_t realsize = size * nmemb;
294  ConnInfo *conn = (ConnInfo*) data;
295  (void)ptr;
296  (void)conn;
297  return realsize;
298}
299
300
301/* CURLOPT_PROGRESSFUNCTION */
302static int prog_cb (void *p, double dltotal, double dlnow, double ult,
303                    double uln)
304{
305  ConnInfo *conn = (ConnInfo *)p;
306  (void)ult;
307  (void)uln;
308
309  fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
310  return 0;
311}
312
313
314/* Create a new easy handle, and add it to the global curl_multi */
315static void new_conn(char *url, GlobalInfo *g)
316{
317  ConnInfo *conn;
318  CURLMcode rc;
319
320  conn = calloc(1, sizeof(ConnInfo));
321  memset(conn, 0, sizeof(ConnInfo));
322  conn->error[0]='\0';
323
324  conn->easy = curl_easy_init();
325  if(!conn->easy) {
326    fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
327    exit(2);
328  }
329  conn->global = g;
330  conn->url = strdup(url);
331  curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
332  curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
333  curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
334  curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
335  curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
336  curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
337  curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
338  curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
339  curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
340  fprintf(MSG_OUT,
341          "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
342  rc = curl_multi_add_handle(g->multi, conn->easy);
343  mcode_or_die("new_conn: curl_multi_add_handle", rc);
344
345  /* note that the add_handle() will set a time-out to trigger very soon so
346     that the necessary socket_action() call will be called by this app */
347}
348
349/* This gets called whenever data is received from the fifo */
350static void fifo_cb(int fd, short event, void *arg)
351{
352  char s[1024];
353  long int rv=0;
354  int n=0;
355  GlobalInfo *g = (GlobalInfo *)arg;
356  (void)fd; /* unused */
357  (void)event; /* unused */
358
359  do {
360    s[0]='\0';
361    rv=fscanf(g->input, "%1023s%n", s, &n);
362    s[n]='\0';
363    if(n && s[0]) {
364      new_conn(s, arg);  /* if we read a URL, go get it! */
365    }
366    else
367      break;
368  } while(rv != EOF);
369}
370
371/* Create a named pipe and tell libevent to monitor it */
372static const char *fifo = "hiper.fifo";
373static int init_fifo (GlobalInfo *g)
374{
375  struct stat st;
376  curl_socket_t sockfd;
377
378  fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
379  if(lstat (fifo, &st) == 0) {
380    if((st.st_mode & S_IFMT) == S_IFREG) {
381      errno = EEXIST;
382      perror("lstat");
383      exit (1);
384    }
385  }
386  unlink(fifo);
387  if(mkfifo (fifo, 0600) == -1) {
388    perror("mkfifo");
389    exit (1);
390  }
391  sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
392  if(sockfd == -1) {
393    perror("open");
394    exit (1);
395  }
396  g->input = fdopen(sockfd, "r");
397
398  fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
399  g->fifo_event = event_new(g->evbase, sockfd, EV_READ|EV_PERSIST, fifo_cb, g);
400  event_add(g->fifo_event, NULL);
401  return (0);
402}
403
404static void clean_fifo(GlobalInfo *g)
405{
406    event_free(g->fifo_event);
407    fclose(g->input);
408    unlink(fifo);
409}
410
411int main(int argc, char **argv)
412{
413  GlobalInfo g;
414  (void)argc;
415  (void)argv;
416
417  memset(&g, 0, sizeof(GlobalInfo));
418  g.evbase = event_base_new();
419  init_fifo(&g);
420  g.multi = curl_multi_init();
421  g.timer_event = evtimer_new(g.evbase, timer_cb, &g);
422
423  /* setup the generic multi interface options we want */
424  curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
425  curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
426  curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
427  curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
428
429  /* we don't call any curl_multi_socket*() function yet as we have no handles
430     added! */
431
432  event_base_dispatch(g.evbase);
433
434  /* this, of course, won't get called since only way to stop this program is
435     via ctrl-C, but it is here to show how cleanup /would/ be done. */
436  clean_fifo(&g);
437  event_free(g.timer_event);
438  event_base_free(g.evbase);
439  curl_multi_cleanup(g.multi);
440  return 0;
441}
442