CURLOPT_CERTINFO(3)        Library Functions Manual        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 extracts 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).

DEFAULT
       0

PROTOCOLS
       All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

       This option works only with the following TLS backends: GnuTLS,
       OpenSSL, Schannel and Secure Transport

EXAMPLE
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode res;
           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) {
               int i;
               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
       Schannel support added in 7.50.0. Secure Transport support added in
       7.79.0.

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

SEE ALSO
       CURLINFO_CAINFO(3), CURLINFO_CAPATH(3), CURLINFO_CERTINFO(3),
       CURLOPT_CAINFO(3), CURLOPT_SSL_VERIFYPEER(3)

libcurl                          April 26 2024             CURLOPT_CERTINFO(3)