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 libuv
27 * </DESC>
28 */
29 /* Use the socket_action interface to download multiple files in parallel,
30 powered by libuv.
31
32 Requires libuv and (of course) libcurl.
33
34 See https://docs.libuv.org/en/v1.x/index.html libuv API documentation
35 */
36
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <uv.h>
40 #include <curl/curl.h>
41
42 /* object to pass to the callbacks */
43 struct datauv {
44 uv_timer_t timeout;
45 uv_loop_t *loop;
46 CURLM *multi;
47 };
48
49 typedef struct curl_context_s {
50 uv_poll_t poll_handle;
51 curl_socket_t sockfd;
52 struct datauv *uv;
53 } curl_context_t;
54
create_curl_context(curl_socket_t sockfd,struct datauv * uv)55 static curl_context_t *create_curl_context(curl_socket_t sockfd,
56 struct datauv *uv)
57 {
58 curl_context_t *context;
59
60 context = (curl_context_t *) malloc(sizeof(*context));
61
62 context->sockfd = sockfd;
63 context->uv = uv;
64
65 uv_poll_init_socket(uv->loop, &context->poll_handle, sockfd);
66 context->poll_handle.data = context;
67
68 return context;
69 }
70
curl_close_cb(uv_handle_t * handle)71 static void curl_close_cb(uv_handle_t *handle)
72 {
73 curl_context_t *context = (curl_context_t *) handle->data;
74 free(context);
75 }
76
destroy_curl_context(curl_context_t * context)77 static void destroy_curl_context(curl_context_t *context)
78 {
79 uv_close((uv_handle_t *) &context->poll_handle, curl_close_cb);
80 }
81
add_download(const char * url,int num,CURLM * multi)82 static void add_download(const char *url, int num, CURLM *multi)
83 {
84 char filename[50];
85 FILE *file;
86 CURL *handle;
87
88 snprintf(filename, 50, "%d.download", num);
89
90 file = fopen(filename, "wb");
91 if(!file) {
92 fprintf(stderr, "Error opening %s\n", filename);
93 return;
94 }
95
96 handle = curl_easy_init();
97 curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
98 curl_easy_setopt(handle, CURLOPT_PRIVATE, file);
99 curl_easy_setopt(handle, CURLOPT_URL, url);
100 curl_multi_add_handle(multi, handle);
101 fprintf(stderr, "Added download %s -> %s\n", url, filename);
102 }
103
check_multi_info(curl_context_t * context)104 static void check_multi_info(curl_context_t *context)
105 {
106 char *done_url;
107 CURLMsg *message;
108 int pending;
109 CURL *easy_handle;
110 FILE *file;
111
112 while((message = curl_multi_info_read(context->uv->multi, &pending))) {
113 switch(message->msg) {
114 case CURLMSG_DONE:
115 /* Do not use message data after calling curl_multi_remove_handle() and
116 curl_easy_cleanup(). As per curl_multi_info_read() docs:
117 "WARNING: The data the returned pointer points to does not survive
118 calling curl_multi_cleanup, curl_multi_remove_handle or
119 curl_easy_cleanup." */
120 easy_handle = message->easy_handle;
121
122 curl_easy_getinfo(easy_handle, CURLINFO_EFFECTIVE_URL, &done_url);
123 curl_easy_getinfo(easy_handle, CURLINFO_PRIVATE, &file);
124 printf("%s DONE\n", done_url);
125
126 curl_multi_remove_handle(context->uv->multi, easy_handle);
127 curl_easy_cleanup(easy_handle);
128 if(file) {
129 fclose(file);
130 }
131 break;
132
133 default:
134 fprintf(stderr, "CURLMSG default\n");
135 break;
136 }
137 }
138 }
139
140 /* callback from libuv on socket activity */
on_uv_socket(uv_poll_t * req,int status,int events)141 static void on_uv_socket(uv_poll_t *req, int status, int events)
142 {
143 int running_handles;
144 int flags = 0;
145 curl_context_t *context = (curl_context_t *) req->data;
146 (void)status;
147 if(events & UV_READABLE)
148 flags |= CURL_CSELECT_IN;
149 if(events & UV_WRITABLE)
150 flags |= CURL_CSELECT_OUT;
151
152 curl_multi_socket_action(context->uv->multi, context->sockfd, flags,
153 &running_handles);
154 check_multi_info(context);
155 }
156
157 /* callback from libuv when timeout expires */
on_uv_timeout(uv_timer_t * req)158 static void on_uv_timeout(uv_timer_t *req)
159 {
160 curl_context_t *context = (curl_context_t *) req->data;
161 if(context) {
162 int running_handles;
163 curl_multi_socket_action(context->uv->multi, CURL_SOCKET_TIMEOUT, 0,
164 &running_handles);
165 check_multi_info(context);
166 }
167 }
168
169 /* callback from libcurl to update the timeout expiry */
cb_timeout(CURLM * multi,long timeout_ms,struct datauv * uv)170 static int cb_timeout(CURLM *multi, long timeout_ms,
171 struct datauv *uv)
172 {
173 (void)multi;
174 if(timeout_ms < 0)
175 uv_timer_stop(&uv->timeout);
176 else {
177 if(timeout_ms == 0)
178 timeout_ms = 1; /* 0 means call curl_multi_socket_action asap but NOT
179 within the callback itself */
180 uv_timer_start(&uv->timeout, on_uv_timeout, (uint64_t)timeout_ms,
181 0); /* do not repeat */
182 }
183 return 0;
184 }
185
186 /* callback from libcurl to update socket activity to wait for */
cb_socket(CURL * easy,curl_socket_t s,int action,struct datauv * uv,void * socketp)187 static int cb_socket(CURL *easy, curl_socket_t s, int action,
188 struct datauv *uv,
189 void *socketp)
190 {
191 curl_context_t *curl_context;
192 int events = 0;
193 (void)easy;
194
195 switch(action) {
196 case CURL_POLL_IN:
197 case CURL_POLL_OUT:
198 case CURL_POLL_INOUT:
199 curl_context = socketp ?
200 (curl_context_t *) socketp : create_curl_context(s, uv);
201
202 curl_multi_assign(uv->multi, s, (void *) curl_context);
203
204 if(action != CURL_POLL_IN)
205 events |= UV_WRITABLE;
206 if(action != CURL_POLL_OUT)
207 events |= UV_READABLE;
208
209 uv_poll_start(&curl_context->poll_handle, events, on_uv_socket);
210 break;
211 case CURL_POLL_REMOVE:
212 if(socketp) {
213 uv_poll_stop(&((curl_context_t*)socketp)->poll_handle);
214 destroy_curl_context((curl_context_t*) socketp);
215 curl_multi_assign(uv->multi, s, NULL);
216 }
217 break;
218 default:
219 abort();
220 }
221
222 return 0;
223 }
224
main(int argc,char ** argv)225 int main(int argc, char **argv)
226 {
227 struct datauv uv = { 0 };
228 int running_handles;
229
230 if(argc <= 1)
231 return 0;
232
233 curl_global_init(CURL_GLOBAL_ALL);
234
235 uv.loop = uv_default_loop();
236 uv_timer_init(uv.loop, &uv.timeout);
237
238 uv.multi = curl_multi_init();
239 curl_multi_setopt(uv.multi, CURLMOPT_SOCKETFUNCTION, cb_socket);
240 curl_multi_setopt(uv.multi, CURLMOPT_SOCKETDATA, &uv);
241 curl_multi_setopt(uv.multi, CURLMOPT_TIMERFUNCTION, cb_timeout);
242 curl_multi_setopt(uv.multi, CURLMOPT_TIMERDATA, &uv);
243
244 while(argc-- > 1) {
245 add_download(argv[argc], argc, uv.multi);
246 }
247
248 /* kickstart the thing */
249 curl_multi_socket_action(uv.multi, CURL_SOCKET_TIMEOUT, 0, &running_handles);
250 uv_run(uv.loop, UV_RUN_DEFAULT);
251 curl_multi_cleanup(uv.multi);
252
253 return 0;
254 }
255
