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      1 /***************************************************************************
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      3  *  Project                     ___| | | |  _ \| |
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      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel (at) 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 http://curl.haxx.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 /* A multi-threaded example that uses pthreads and fetches 4 remote files at
     23  * once over HTTPS. The lock callbacks and stuff assume OpenSSL or GnuTLS
     24  * (libgcrypt) so far.
     25  *
     26  * OpenSSL docs for this:
     27  *   http://www.openssl.org/docs/crypto/threads.html
     28  * gcrypt docs for this:
     29  *   http://gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
     30  */
     31 
     32 #define USE_OPENSSL /* or USE_GNUTLS accordingly */
     33 
     34 #include <stdio.h>
     35 #include <pthread.h>
     36 #include <curl/curl.h>
     37 
     38 #define NUMT 4
     39 
     40 /* we have this global to let the callback get easy access to it */
     41 static pthread_mutex_t *lockarray;
     42 
     43 #ifdef USE_OPENSSL
     44 #include <openssl/crypto.h>
     45 static void lock_callback(int mode, int type, char *file, int line)
     46 {
     47   (void)file;
     48   (void)line;
     49   if (mode & CRYPTO_LOCK) {
     50     pthread_mutex_lock(&(lockarray[type]));
     51   }
     52   else {
     53     pthread_mutex_unlock(&(lockarray[type]));
     54   }
     55 }
     56 
     57 static unsigned long thread_id(void)
     58 {
     59   unsigned long ret;
     60 
     61   ret=(unsigned long)pthread_self();
     62   return(ret);
     63 }
     64 
     65 static void init_locks(void)
     66 {
     67   int i;
     68 
     69   lockarray=(pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
     70                                             sizeof(pthread_mutex_t));
     71   for (i=0; i<CRYPTO_num_locks(); i++) {
     72     pthread_mutex_init(&(lockarray[i]),NULL);
     73   }
     74 
     75   CRYPTO_set_id_callback((unsigned long (*)())thread_id);
     76   CRYPTO_set_locking_callback((void (*)())lock_callback);
     77 }
     78 
     79 static void kill_locks(void)
     80 {
     81   int i;
     82 
     83   CRYPTO_set_locking_callback(NULL);
     84   for (i=0; i<CRYPTO_num_locks(); i++)
     85     pthread_mutex_destroy(&(lockarray[i]));
     86 
     87   OPENSSL_free(lockarray);
     88 }
     89 #endif
     90 
     91 #ifdef USE_GNUTLS
     92 #include <gcrypt.h>
     93 #include <errno.h>
     94 
     95 GCRY_THREAD_OPTION_PTHREAD_IMPL;
     96 
     97 void init_locks(void)
     98 {
     99   gcry_control(GCRYCTL_SET_THREAD_CBS);
    100 }
    101 
    102 #define kill_locks()
    103 #endif
    104 
    105 /* List of URLs to fetch.*/
    106 const char * const urls[]= {
    107   "https://www.example.com/",
    108   "https://www2.example.com/",
    109   "https://www3.example.com/",
    110   "https://www4.example.com/",
    111 };
    112 
    113 static void *pull_one_url(void *url)
    114 {
    115   CURL *curl;
    116 
    117   curl = curl_easy_init();
    118   curl_easy_setopt(curl, CURLOPT_URL, url);
    119   /* this example doesn't verify the server's certificate, which means we
    120      might be downloading stuff from an impostor */
    121   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
    122   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
    123   curl_easy_perform(curl); /* ignores error */
    124   curl_easy_cleanup(curl);
    125 
    126   return NULL;
    127 }
    128 
    129 int main(int argc, char **argv)
    130 {
    131   pthread_t tid[NUMT];
    132   int i;
    133   int error;
    134   (void)argc; /* we don't use any arguments in this example */
    135   (void)argv;
    136 
    137   /* Must initialize libcurl before any threads are started */
    138   curl_global_init(CURL_GLOBAL_ALL);
    139 
    140   init_locks();
    141 
    142   for(i=0; i< NUMT; i++) {
    143     error = pthread_create(&tid[i],
    144                            NULL, /* default attributes please */
    145                            pull_one_url,
    146                            (void *)urls[i]);
    147     if(0 != error)
    148       fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
    149     else
    150       fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
    151   }
    152 
    153   /* now wait for all threads to terminate */
    154   for(i=0; i< NUMT; i++) {
    155     error = pthread_join(tid[i], NULL);
    156     fprintf(stderr, "Thread %d terminated\n", i);
    157   }
    158 
    159   kill_locks();
    160 
    161   return 0;
    162 }
    163