curl/docs/examples/threaded-ssl.c

   1 /*****************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * $Id: threaded-ssl.c,v 1.4 2008-05-22 21:20:09 danf Exp $
   9  *
  10  * A multi-threaded example that uses pthreads and fetches 4 remote files at
  11  * once over HTTPS. The lock callbacks and stuff assume OpenSSL or GnuTLS
  12  * (libgcrypt) so far.
  13  *
  14  * OpenSSL docs for this:
  15  *   http://www.openssl.org/docs/crypto/threads.html
  16  * gcrypt docs for this:
  17  *   http://gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
  18  */
  19
  20 #define USE_OPENSSL /* or USE_GNUTLS accordingly */
  21
  22 #include <stdio.h>
  23 #include <pthread.h>
  24 #include <curl/curl.h>
  25
  26 #define NUMT 4
  27
  28 /* we have this global to let the callback get easy access to it */
  29 static pthread_mutex_t *lockarray;
  30
  31 #ifdef USE_OPENSSL
  32 #include <openssl/crypto.h>
  33 static void lock_callback(int mode, int type, char *file, int line)
  34 {
  35   (void)file;
  36   (void)line;
  37   if (mode & CRYPTO_LOCK) {
  38     pthread_mutex_lock(&(lockarray[type]));
  39   }
  40   else {
  41     pthread_mutex_unlock(&(lockarray[type]));
  42   }
  43 }
  44
  45 static unsigned long thread_id(void)
  46 {
  47   unsigned long ret;
  48
  49   ret=(unsigned long)pthread_self();
  50   return(ret);
  51 }
  52
  53 static void init_locks(void)
  54 {
  55   int i;
  56
  57   lockarray=(pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
  58                                             sizeof(pthread_mutex_t));
  59   for (i=0; i<CRYPTO_num_locks(); i++) {
  60     pthread_mutex_init(&(lockarray[i]),NULL);
  61   }
  62
  63   CRYPTO_set_id_callback((unsigned long (*)())thread_id);
  64   CRYPTO_set_locking_callback((void (*)())lock_callback);
  65 }
  66
  67 static void kill_locks(void)
  68 {
  69   int i;
  70
  71   CRYPTO_set_locking_callback(NULL);
  72   for (i=0; i<CRYPTO_num_locks(); i++)
  73     pthread_mutex_destroy(&(lockarray[i]));
  74
  75   OPENSSL_free(lockarray);
  76 }
  77 #endif
  78
  79 #ifdef USE_GNUTLS
  80 #include <gcrypt.h>
  81 #include <errno.h>
  82
  83 GCRY_THREAD_OPTION_PTHREAD_IMPL;
  84
  85 void init_locks(void)
  86 {
  87   gcry_control(GCRYCTL_SET_THREAD_CBS);
  88 }
  89
  90 #define kill_locks()
  91 #endif
  92
  93 /* List of URLs to fetch.*/
  94 const char * const urls[]= {
  95   "https://www.sf.net/",
  96   "https://www.openssl.org/",
  97   "https://www.sf.net/",
  98   "https://www.openssl.org/",
  99 };
 100
 101 static void *pull_one_url(void *url)
 102 {
 103   CURL *curl;
 104
 105   curl = curl_easy_init();
 106   curl_easy_setopt(curl, CURLOPT_URL, url);
 107   /* this example doesn't verify the server's certificate, which means we
 108      might be downloading stuff from an impostor */
 109   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
 110   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
 111   curl_easy_perform(curl); /* ignores error */
 112   curl_easy_cleanup(curl);
 113
 114   return NULL;
 115 }
 116
 117 int main(int argc, char **argv)
 118 {
 119   pthread_t tid[NUMT];
 120   int i;
 121   int error;
 122   (void)argc; /* we don't use any arguments in this example */
 123   (void)argv;
 124
 125   /* Must initialize libcurl before any threads are started */
 126   curl_global_init(CURL_GLOBAL_ALL);
 127
 128   init_locks();
 129
 130   for(i=0; i< NUMT; i++) {
 131     error = pthread_create(&tid[i],
 132                            NULL, /* default attributes please */
 133                            pull_one_url,
 134                            (void *)urls[i]);
 135     if(0 != error)
 136       fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
 137     else
 138       fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
 139   }
 140
 141   /* now wait for all threads to terminate */
 142   for(i=0; i< NUMT; i++) {
 143     error = pthread_join(tid[i], NULL);
 144     fprintf(stderr, "Thread %d terminated\n", i);
 145   }
 146
 147   kill_locks();
 148
 149   return 0;
 150 }