#include <stdio.h>
#include <curl/curl.h>
#include <gnutls/gnutls.h>
static CURL *curl;
static size_t wrfu(void *ptr, size_t size, size_t nmemb, void *stream)
{
const struct curl_tlssessioninfo *info;
unsigned int cert_list_size;
const gnutls_datum_t *chainp;
CURLcode res;
(void)stream;
(void)ptr;
res = curl_easy_getinfo(curl, CURLINFO_TLS_SESSION, &info);
if(!res) {
switch(info->backend) {
case CURLSSLBACKEND_GNUTLS:
chainp = gnutls_certificate_get_peers(info->internals, &cert_list_size);
if((chainp) && (cert_list_size)) {
unsigned int i;
for(i = 0; i < cert_list_size; i++) {
gnutls_x509_crt_t cert;
gnutls_datum_t dn;
if(GNUTLS_E_SUCCESS == gnutls_x509_crt_init(&cert)) {
if(GNUTLS_E_SUCCESS ==
gnutls_x509_crt_import(cert, &chainp[i], GNUTLS_X509_FMT_DER)) {
if(GNUTLS_E_SUCCESS ==
gnutls_x509_crt_print(cert, GNUTLS_CRT_PRINT_FULL, &dn)) {
fprintf(stderr, "Certificate #%d: %.*s", i, dn.size, dn.data);
gnutls_free(dn.data);
}
}
gnutls_x509_crt_deinit(cert);
}
}
}
break;
case CURLSSLBACKEND_NONE:
default:
break;
}
}
return size * nmemb;
}
int main(void)
{
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.com/");
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, wrfu);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 0L);
(void) curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
curl_global_cleanup();
return 0;
}