aboutsummaryrefslogtreecommitdiff
path: root/docs/examples/threaded-ssl.c
blob: 16da37a80ec67a79641e5dc114a9743795275b81 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/
/* <DESC>
 * Show the required mutex callback setups for GnuTLS and OpenSSL when using
 * libcurl multi-threaded.
 * </DESC>
 */
/* A multi-threaded example that uses pthreads and fetches 4 remote files at
 * once over HTTPS. The lock callbacks and stuff assume OpenSSL <1.1 or GnuTLS
 * (libgcrypt) so far.
 *
 * OpenSSL docs for this:
 *   https://www.openssl.org/docs/crypto/threads.html
 * gcrypt docs for this:
 *   https://gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
 */

#define USE_OPENSSL /* or USE_GNUTLS accordingly */

#include <stdio.h>
#include <pthread.h>
#include <curl/curl.h>

#define NUMT 4

/* we have this global to let the callback get easy access to it */
static pthread_mutex_t *lockarray;

#ifdef USE_OPENSSL
#include <openssl/crypto.h>
static void lock_callback(int mode, int type, char *file, int line)
{
  (void)file;
  (void)line;
  if(mode & CRYPTO_LOCK) {
    pthread_mutex_lock(&(lockarray[type]));
  }
  else {
    pthread_mutex_unlock(&(lockarray[type]));
  }
}

static unsigned long thread_id(void)
{
  unsigned long ret;

  ret=(unsigned long)pthread_self();
  return ret;
}

static void init_locks(void)
{
  int i;

  lockarray=(pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
                                            sizeof(pthread_mutex_t));
  for(i=0; i<CRYPTO_num_locks(); i++) {
    pthread_mutex_init(&(lockarray[i]), NULL);
  }

  CRYPTO_set_id_callback((unsigned long (*)())thread_id);
  CRYPTO_set_locking_callback((void (*)())lock_callback);
}

static void kill_locks(void)
{
  int i;

  CRYPTO_set_locking_callback(NULL);
  for(i=0; i<CRYPTO_num_locks(); i++)
    pthread_mutex_destroy(&(lockarray[i]));

  OPENSSL_free(lockarray);
}
#endif

#ifdef USE_GNUTLS
#include <gcrypt.h>
#include <errno.h>

GCRY_THREAD_OPTION_PTHREAD_IMPL;

void init_locks(void)
{
  gcry_control(GCRYCTL_SET_THREAD_CBS);
}

#define kill_locks()
#endif

/* List of URLs to fetch.*/
const char * const urls[]= {
  "https://www.example.com/",
  "https://www2.example.com/",
  "https://www3.example.com/",
  "https://www4.example.com/",
};

static void *pull_one_url(void *url)
{
  CURL *curl;

  curl = curl_easy_init();
  curl_easy_setopt(curl, CURLOPT_URL, url);
  /* this example doesn't verify the server's certificate, which means we
     might be downloading stuff from an impostor */
  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
  curl_easy_perform(curl); /* ignores error */
  curl_easy_cleanup(curl);

  return NULL;
}

int main(int argc, char **argv)
{
  pthread_t tid[NUMT];
  int i;
  int error;
  (void)argc; /* we don't use any arguments in this example */
  (void)argv;

  /* Must initialize libcurl before any threads are started */
  curl_global_init(CURL_GLOBAL_ALL);

  init_locks();

  for(i=0; i< NUMT; i++) {
    error = pthread_create(&tid[i],
                           NULL, /* default attributes please */
                           pull_one_url,
                           (void *)urls[i]);
    if(0 != error)
      fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
    else
      fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
  }

  /* now wait for all threads to terminate */
  for(i=0; i< NUMT; i++) {
    error = pthread_join(tid[i], NULL);
    fprintf(stderr, "Thread %d terminated\n", i);
  }

  kill_locks();

  return 0;
}