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.TH CURLINFO_CERTINFO 3 "August 22, 2023" "libcurl 8.3.0" "libcurl"

.SH NAME
CURLINFO_CERTINFO \- get the TLS certificate chain
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_CERTINFO,
                           struct curl_certinfo **chainp);
.fi
.SH DESCRIPTION
Pass a pointer to a \fIstruct curl_certinfo *\fP and it is set to point to a
struct that holds info about the server's certificate chain, assuming you had
\fICURLOPT_CERTINFO(3)\fP enabled when the request was made.

.nf
struct curl_certinfo {
  int num_of_certs;
  struct curl_slist **certinfo;
};
.fi

The \fIcertinfo\fP struct member is an array of linked lists of certificate
information. The \fInum_of_certs\fP 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.
.SH PROTOCOLS
All TLS-based
.SH EXAMPLE
.nf
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);
}
.fi

See also the \fIcertinfo.c\fP example.
.SH AVAILABILITY
This option is only working in libcurl built with OpenSSL, GnuTLS, Schannel or
Secure Transport. GnuTLS support added in 7.42.0. Schannel support added in
7.50.0. Secure Transport support added in 7.79.0.

Added in 7.19.1
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR curl_easy_getinfo "(3), " curl_easy_setopt "(3), "