xref: /curl/docs/examples/threaded-ssl.c (revision fbf5d507)
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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.
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14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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16  * furnished to do so, under the terms of the COPYING file.
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18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
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21  * SPDX-License-Identifier: curl
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23  ***************************************************************************/
24 /* <DESC>
25  * Show the required mutex callback setups for GnuTLS and OpenSSL when using
26  * libcurl multi-threaded.
27  * </DESC>
28  */
29 /* A multi-threaded example that uses pthreads and fetches 4 remote files at
30  * once over HTTPS.
31  *
32  * Recent versions of OpenSSL and GnuTLS are thread safe by design, assuming
33  * support for the underlying OS threading API is built-in. Older revisions
34  * of this example demonstrated locking callbacks for the SSL library, which
35  * are no longer necessary. An older revision with callbacks can be found at
36  * https://github.com/curl/curl/blob/curl-7_88_1/docs/examples/threaded-ssl.c
37  */
38 
39 #define USE_OPENSSL /* or USE_GNUTLS accordingly */
40 
41 #include <stdio.h>
42 #include <pthread.h>
43 #include <curl/curl.h>
44 
45 #define NUMT 4
46 
47 /* List of URLs to fetch.*/
48 const char * const urls[]= {
49   "https://www.example.com/",
50   "https://www2.example.com/",
51   "https://www3.example.com/",
52   "https://www4.example.com/",
53 };
54 
pull_one_url(void * url)55 static void *pull_one_url(void *url)
56 {
57   CURL *curl;
58 
59   curl = curl_easy_init();
60   curl_easy_setopt(curl, CURLOPT_URL, url);
61   /* this example does not verify the server's certificate, which means we
62      might be downloading stuff from an impostor */
63   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
64   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
65   curl_easy_perform(curl); /* ignores error */
66   curl_easy_cleanup(curl);
67 
68   return NULL;
69 }
70 
main(int argc,char ** argv)71 int main(int argc, char **argv)
72 {
73   pthread_t tid[NUMT];
74   int i;
75   (void)argc; /* we do not use any arguments in this example */
76   (void)argv;
77 
78   /* Must initialize libcurl before any threads are started */
79   curl_global_init(CURL_GLOBAL_ALL);
80 
81   for(i = 0; i < NUMT; i++) {
82     int error = pthread_create(&tid[i],
83                                NULL, /* default attributes please */
84                                pull_one_url,
85                                (void *)urls[i]);
86     if(0 != error)
87       fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
88     else
89       fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
90   }
91 
92   /* now wait for all threads to terminate */
93   for(i = 0; i < NUMT; i++) {
94     pthread_join(tid[i], NULL);
95     fprintf(stderr, "Thread %d terminated\n", i);
96   }
97 
98   return 0;
99 }
100