NAME

       CURLINFO_CERTINFO - get the TLS certificate chain

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_CERTINFO,
                                  struct curl_certinfo **chainp);

DESCRIPTION

       Pass  a  pointer to a struct curl_certinfo * and it is set to point to a struct that holds
       info about the server's certificate chain, assuming you  had  CURLOPT_CERTINFO(3)  enabled
       when the request was made.

       struct curl_certinfo {
         int num_of_certs;
         struct curl_slist **certinfo;
       };

       The  certinfo  struct  member  is an array of linked lists of certificate information. The
       num_of_certs struct member is the number of certificates which is the number  of  elements
       in  the  array.  Each  certificate's list has items with textual information in the format
       "name:content" such as "Subject:Foo", "Issuer:Bar", etc. The items  in  each  list  varies
       depending on the SSL backend and the certificate.

PROTOCOLS

       This functionality affects 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) {
             int i;
             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);
         }
       }

       See also the certinfo.c example.

HISTORY

       GnuTLS support added in 7.42.0. Schannel support added in 7.50.0. Secure Transport support
       added in 7.79.0. mbedTLS support added in 8.9.0.

AVAILABILITY

       Added in curl 7.19.1

RETURN VALUE

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

SEE ALSO

       CURLINFO_CAPATH(3), curl_easy_getinfo(3), curl_easy_setopt(3)