1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2020, 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 ***************************************************************************/
22 /* <DESC>
23 * Show the required mutex callback setups for GnuTLS and OpenSSL when using
24 * libcurl multi-threaded.
25 * </DESC>
26 */
27 /* A multi-threaded example that uses pthreads and fetches 4 remote files at
28 * once over HTTPS. The lock callbacks and stuff assume OpenSSL <1.1 or GnuTLS
29 * (libgcrypt) so far.
30 *
31 * OpenSSL docs for this:
32 * https://www.openssl.org/docs/man1.0.2/man3/CRYPTO_num_locks.html
33 * gcrypt docs for this:
34 * https://gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
35 */
36
37 #define USE_OPENSSL /* or USE_GNUTLS accordingly */
38
39 #include <stdio.h>
40 #include <pthread.h>
41 #include <curl/curl.h>
42
43 #define NUMT 4
44
45 /* we have this global to let the callback get easy access to it */
46 static pthread_mutex_t *lockarray;
47
48 #ifdef USE_OPENSSL
49 #include <openssl/crypto.h>
lock_callback(int mode,int type,char * file,int line)50 static void lock_callback(int mode, int type, char *file, int line)
51 {
52 (void)file;
53 (void)line;
54 if(mode & CRYPTO_LOCK) {
55 pthread_mutex_lock(&(lockarray[type]));
56 }
57 else {
58 pthread_mutex_unlock(&(lockarray[type]));
59 }
60 }
61
thread_id(void)62 static unsigned long thread_id(void)
63 {
64 unsigned long ret;
65
66 ret = (unsigned long)pthread_self();
67 return ret;
68 }
69
init_locks(void)70 static void init_locks(void)
71 {
72 int i;
73
74 lockarray = (pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
75 sizeof(pthread_mutex_t));
76 for(i = 0; i<CRYPTO_num_locks(); i++) {
77 pthread_mutex_init(&(lockarray[i]), NULL);
78 }
79
80 CRYPTO_set_id_callback((unsigned long (*)())thread_id);
81 CRYPTO_set_locking_callback((void (*)())lock_callback);
82 }
83
kill_locks(void)84 static void kill_locks(void)
85 {
86 int i;
87
88 CRYPTO_set_locking_callback(NULL);
89 for(i = 0; i<CRYPTO_num_locks(); i++)
90 pthread_mutex_destroy(&(lockarray[i]));
91
92 OPENSSL_free(lockarray);
93 }
94 #endif
95
96 #ifdef USE_GNUTLS
97 #include <gcrypt.h>
98 #include <errno.h>
99
100 GCRY_THREAD_OPTION_PTHREAD_IMPL;
101
init_locks(void)102 void init_locks(void)
103 {
104 gcry_control(GCRYCTL_SET_THREAD_CBS);
105 }
106
107 #define kill_locks()
108 #endif
109
110 /* List of URLs to fetch.*/
111 const char * const urls[]= {
112 "https://www.example.com/",
113 "https://www2.example.com/",
114 "https://www3.example.com/",
115 "https://www4.example.com/",
116 };
117
pull_one_url(void * url)118 static void *pull_one_url(void *url)
119 {
120 CURL *curl;
121
122 curl = curl_easy_init();
123 curl_easy_setopt(curl, CURLOPT_URL, url);
124 /* this example doesn't verify the server's certificate, which means we
125 might be downloading stuff from an impostor */
126 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
127 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
128 curl_easy_perform(curl); /* ignores error */
129 curl_easy_cleanup(curl);
130
131 return NULL;
132 }
133
main(int argc,char ** argv)134 int main(int argc, char **argv)
135 {
136 pthread_t tid[NUMT];
137 int i;
138 (void)argc; /* we don't use any arguments in this example */
139 (void)argv;
140
141 /* Must initialize libcurl before any threads are started */
142 curl_global_init(CURL_GLOBAL_ALL);
143
144 init_locks();
145
146 for(i = 0; i< NUMT; i++) {
147 int error = pthread_create(&tid[i],
148 NULL, /* default attributes please */
149 pull_one_url,
150 (void *)urls[i]);
151 if(0 != error)
152 fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
153 else
154 fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
155 }
156
157 /* now wait for all threads to terminate */
158 for(i = 0; i< NUMT; i++) {
159 pthread_join(tid[i], NULL);
160 fprintf(stderr, "Thread %d terminated\n", i);
161 }
162
163 kill_locks();
164
165 return 0;
166 }
167