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
25/* <DESC>
26 * multi_socket API using libevent
27 * </DESC>
28 */
29
30#include <stdio.h>
31#include <stdlib.h>
32#include <event2/event.h>
33#include <curl/curl.h>
34
35struct event_base *base;
36CURLM *curl_handle;
37struct event *timeout;
38
39typedef struct curl_context_s {
40  struct event *event;
41  curl_socket_t sockfd;
42} curl_context_t;
43
44static void curl_perform(int fd, short event, void *arg);
45
46static curl_context_t *create_curl_context(curl_socket_t sockfd)
47{
48  curl_context_t *context;
49
50  context = (curl_context_t *) malloc(sizeof(*context));
51
52  context->sockfd = sockfd;
53
54  context->event = event_new(base, sockfd, 0, curl_perform, context);
55
56  return context;
57}
58
59static void destroy_curl_context(curl_context_t *context)
60{
61  event_del(context->event);
62  event_free(context->event);
63  free(context);
64}
65
66static void add_download(const char *url, int num)
67{
68  char filename[50];
69  FILE *file;
70  CURL *handle;
71
72  snprintf(filename, 50, "%d.download", num);
73
74  file = fopen(filename, "wb");
75  if(!file) {
76    fprintf(stderr, "Error opening %s\n", filename);
77    return;
78  }
79
80  handle = curl_easy_init();
81  curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
82  curl_easy_setopt(handle, CURLOPT_PRIVATE, file);
83  curl_easy_setopt(handle, CURLOPT_URL, url);
84  curl_multi_add_handle(curl_handle, handle);
85  fprintf(stderr, "Added download %s -> %s\n", url, filename);
86}
87
88static void check_multi_info(void)
89{
90  char *done_url;
91  CURLMsg *message;
92  int pending;
93  CURL *easy_handle;
94  FILE *file;
95
96  while((message = curl_multi_info_read(curl_handle, &pending))) {
97    switch(message->msg) {
98    case CURLMSG_DONE:
99      /* Do not use message data after calling curl_multi_remove_handle() and
100         curl_easy_cleanup(). As per curl_multi_info_read() docs:
101         "WARNING: The data the returned pointer points to will not survive
102         calling curl_multi_cleanup, curl_multi_remove_handle or
103         curl_easy_cleanup." */
104      easy_handle = message->easy_handle;
105
106      curl_easy_getinfo(easy_handle, CURLINFO_EFFECTIVE_URL, &done_url);
107      curl_easy_getinfo(easy_handle, CURLINFO_PRIVATE, &file);
108      printf("%s DONE\n", done_url);
109
110      curl_multi_remove_handle(curl_handle, easy_handle);
111      curl_easy_cleanup(easy_handle);
112      if(file) {
113        fclose(file);
114      }
115      break;
116
117    default:
118      fprintf(stderr, "CURLMSG default\n");
119      break;
120    }
121  }
122}
123
124static void curl_perform(int fd, short event, void *arg)
125{
126  int running_handles;
127  int flags = 0;
128  curl_context_t *context;
129
130  if(event & EV_READ)
131    flags |= CURL_CSELECT_IN;
132  if(event & EV_WRITE)
133    flags |= CURL_CSELECT_OUT;
134
135  context = (curl_context_t *) arg;
136
137  curl_multi_socket_action(curl_handle, context->sockfd, flags,
138                           &running_handles);
139
140  check_multi_info();
141}
142
143static void on_timeout(evutil_socket_t fd, short events, void *arg)
144{
145  int running_handles;
146  curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0,
147                           &running_handles);
148  check_multi_info();
149}
150
151static int start_timeout(CURLM *multi, long timeout_ms, void *userp)
152{
153  if(timeout_ms < 0) {
154    evtimer_del(timeout);
155  }
156  else {
157    if(timeout_ms == 0)
158      timeout_ms = 1; /* 0 means directly call socket_action, but we will do it
159                         in a bit */
160    struct timeval tv;
161    tv.tv_sec = timeout_ms / 1000;
162    tv.tv_usec = (timeout_ms % 1000) * 1000;
163    evtimer_del(timeout);
164    evtimer_add(timeout, &tv);
165  }
166  return 0;
167}
168
169static int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp,
170                  void *socketp)
171{
172  curl_context_t *curl_context;
173  int events = 0;
174
175  switch(action) {
176  case CURL_POLL_IN:
177  case CURL_POLL_OUT:
178  case CURL_POLL_INOUT:
179    curl_context = socketp ?
180      (curl_context_t *) socketp : create_curl_context(s);
181
182    curl_multi_assign(curl_handle, s, (void *) curl_context);
183
184    if(action != CURL_POLL_IN)
185      events |= EV_WRITE;
186    if(action != CURL_POLL_OUT)
187      events |= EV_READ;
188
189    events |= EV_PERSIST;
190
191    event_del(curl_context->event);
192    event_assign(curl_context->event, base, curl_context->sockfd, events,
193      curl_perform, curl_context);
194    event_add(curl_context->event, NULL);
195
196    break;
197  case CURL_POLL_REMOVE:
198    if(socketp) {
199      event_del(((curl_context_t*) socketp)->event);
200      destroy_curl_context((curl_context_t*) socketp);
201      curl_multi_assign(curl_handle, s, NULL);
202    }
203    break;
204  default:
205    abort();
206  }
207
208  return 0;
209}
210
211int main(int argc, char **argv)
212{
213  if(argc <= 1)
214    return 0;
215
216  if(curl_global_init(CURL_GLOBAL_ALL)) {
217    fprintf(stderr, "Could not init curl\n");
218    return 1;
219  }
220
221  base = event_base_new();
222  timeout = evtimer_new(base, on_timeout, NULL);
223
224  curl_handle = curl_multi_init();
225  curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket);
226  curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout);
227
228  while(argc-- > 1) {
229    add_download(argv[argc], argc);
230  }
231
232  event_base_dispatch(base);
233
234  curl_multi_cleanup(curl_handle);
235  event_free(timeout);
236  event_base_free(base);
237
238  libevent_global_shutdown();
239  curl_global_cleanup();
240
241  return 0;
242}
243