CURLOPT_CERTINFO(3)        curl_easy_setopt options        CURLOPT_CERTINFO(3)

NAME
       CURLOPT_CERTINFO - request SSL certificate information

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CERTINFO, long
       certinfo);

DESCRIPTION
       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
       _easy_getinfo&section=3">curl_easy_getinfo(3) and its option _CERTINFO&section=3">CURLINFO_CERTINFO(3).

DEFAULT
       0

PROTOCOLS
       All TLS-based

EXAMPLE
       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);
       }

AVAILABILITY
       This option is supported by the OpenSSL, GnuTLS, Schannel, NSS and
       GSKit backends.

RETURN VALUE
       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
       if not.

SEE ALSO
       CURLOPT_CAINFO(3), CURLOPT_SSL_VERIFYPEER(3),

libcurl 7.77.0                 November 4, 2020            CURLOPT_CERTINFO(3)