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/* <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. The lock callbacks and stuff assume OpenSSL <1.1 or GnuTLS
31 * (libgcrypt) so far.
32 *
33 * OpenSSL docs for this:
34 *   https://www.openssl.org/docs/man1.0.2/man3/CRYPTO_num_locks.html
35 * gcrypt docs for this:
36 *   https://gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
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/* we have this global to let the callback get easy access to it */
48static pthread_mutex_t *lockarray;
49
50#ifdef USE_OPENSSL
51#include <openssl/crypto.h>
52static void lock_callback(int mode, int type, char *file, int line)
53{
54  (void)file;
55  (void)line;
56  if(mode & CRYPTO_LOCK) {
57    pthread_mutex_lock(&(lockarray[type]));
58  }
59  else {
60    pthread_mutex_unlock(&(lockarray[type]));
61  }
62}
63
64static unsigned long thread_id(void)
65{
66  unsigned long ret;
67
68  ret = (unsigned long)pthread_self();
69  return ret;
70}
71
72static void init_locks(void)
73{
74  int i;
75
76  lockarray = (pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
77                                                sizeof(pthread_mutex_t));
78  for(i = 0; i<CRYPTO_num_locks(); i++) {
79    pthread_mutex_init(&(lockarray[i]), NULL);
80  }
81
82  CRYPTO_set_id_callback((unsigned long (*)())thread_id);
83  CRYPTO_set_locking_callback((void (*)())lock_callback);
84}
85
86static void kill_locks(void)
87{
88  int i;
89
90  CRYPTO_set_locking_callback(NULL);
91  for(i = 0; i<CRYPTO_num_locks(); i++)
92    pthread_mutex_destroy(&(lockarray[i]));
93
94  OPENSSL_free(lockarray);
95}
96#endif
97
98#ifdef USE_GNUTLS
99#include <gcrypt.h>
100#include <errno.h>
101
102GCRY_THREAD_OPTION_PTHREAD_IMPL;
103
104void init_locks(void)
105{
106  gcry_control(GCRYCTL_SET_THREAD_CBS);
107}
108
109#define kill_locks()
110#endif
111
112/* List of URLs to fetch.*/
113const char * const urls[]= {
114  "https://www.example.com/",
115  "https://www2.example.com/",
116  "https://www3.example.com/",
117  "https://www4.example.com/",
118};
119
120static void *pull_one_url(void *url)
121{
122  CURL *curl;
123
124  curl = curl_easy_init();
125  curl_easy_setopt(curl, CURLOPT_URL, url);
126  /* this example does not verify the server's certificate, which means we
127     might be downloading stuff from an impostor */
128  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
129  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
130  curl_easy_perform(curl); /* ignores error */
131  curl_easy_cleanup(curl);
132
133  return NULL;
134}
135
136int main(int argc, char **argv)
137{
138  pthread_t tid[NUMT];
139  int i;
140  (void)argc; /* we do not use any arguments in this example */
141  (void)argv;
142
143  /* Must initialize libcurl before any threads are started */
144  curl_global_init(CURL_GLOBAL_ALL);
145
146  init_locks();
147
148  for(i = 0; i< NUMT; i++) {
149    int error = pthread_create(&tid[i],
150                               NULL, /* default attributes please */
151                               pull_one_url,
152                               (void *)urls[i]);
153    if(0 != error)
154      fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
155    else
156      fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
157  }
158
159  /* now wait for all threads to terminate */
160  for(i = 0; i< NUMT; i++) {
161    pthread_join(tid[i], NULL);
162    fprintf(stderr, "Thread %d terminated\n", i);
163  }
164
165  kill_locks();
166
167  return 0;
168}
169