**************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2019, 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.
*
**************************************************************************

CURLOPT_CERTINFO - request SSL certificate information #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CERTINFO, long certinfo); Pass a long set to 1 to enable libcurl's certificate chain info gatherer. With this enabled, libcurl will extract lots of information and data about the certificates in the certificate chain used in the SSL connection. This data may then be retrieved after a transfer using curl_easy_getinfo(3) and its option CURLINFO_CERTINFO(3). 0 All TLS-based

curl = curl_easy_init();
if(curl) {
 curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.com/");

 /* connect to any HTTPS site, trusted or not */
 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);

 curl_easy_setopt(curl, CURLOPT_CERTINFO, 1L);

 res = curl_easy_perform(curl);

 if (!res) {
 struct curl_certinfo *ci;
 res = curl_easy_getinfo(curl, CURLINFO_CERTINFO, &ci);

 if (!res) {
 printf("%d certs!\\n", ci->num_of_certs);

 for(i = 0; i < ci->num_of_certs; i++) {
 struct curl_slist *slist;

 for(slist = ci->certinfo[i]; slist; slist = slist->next)
 printf("%s\\n", slist->data);
 }
 }
 }
 curl_easy_cleanup(curl);
}

This option is supported by the OpenSSL, GnuTLS, Schannel, NSS and GSKit backends. Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. CURLOPT_CAINFO "(3), " CURLOPT_SSL_VERIFYPEER "(3), "