1 files changed, 125 insertions, 0 deletions
diff --git a/doc/examples/ex-x509-info.c b/doc/examples/ex-x509-info.c
new file mode 100644
index 0000000..a54aeff
--- /dev/null
+++ b/doc/examples/ex-x509-info.c
@@ -0,0 +1,125 @@
+/* This example code is placed in the public domain. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#include "examples.h"
+
+static const char *bin2hex(const void *bin, size_t bin_size)
+{
+        static char printable[110];
+        const unsigned char *_bin = bin;
+        char *print;
+        size_t i;
+
+        if (bin_size > 50)
+                bin_size = 50;
+
+        print = printable;
+        for (i = 0; i < bin_size; i++) {
+                sprintf(print, "%.2x ", _bin[i]);
+                print += 2;
+        }
+
+        return printable;
+}
+
+/* This function will print information about this session's peer
+ * certificate.
+ */
+void print_x509_certificate_info(gnutls_session_t session)
+{
+        char serial[40];
+        char dn[256];
+        size_t size;
+        unsigned int algo, bits;
+        time_t expiration_time, activation_time;
+        const gnutls_datum_t *cert_list;
+        unsigned int cert_list_size = 0;
+        gnutls_x509_crt_t cert;
+        gnutls_datum_t cinfo;
+
+        /* This function only works for X.509 certificates.
+         */
+        if (gnutls_certificate_type_get(session) != GNUTLS_CRT_X509)
+                return;
+
+        cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
+
+        printf("Peer provided %d certificates.\n", cert_list_size);
+
+        if (cert_list_size > 0) {
+                int ret;
+
+                /* we only print information about the first certificate.
+                 */
+                gnutls_x509_crt_init(&cert);
+
+                gnutls_x509_crt_import(cert, &cert_list[0],
+                                       GNUTLS_X509_FMT_DER);
+
+                printf("Certificate info:\n");
+
+                /* This is the preferred way of printing short information about
+                   a certificate. */
+
+                ret =
+                    gnutls_x509_crt_print(cert, GNUTLS_CRT_PRINT_ONELINE,
+                                          &cinfo);
+                if (ret == 0) {
+                        printf("\t%s\n", cinfo.data);
+                        gnutls_free(cinfo.data);
+                }
+
+                /* If you want to extract fields manually for some other reason,
+                   below are popular example calls. */
+
+                expiration_time =
+                    gnutls_x509_crt_get_expiration_time(cert);
+                activation_time =
+                    gnutls_x509_crt_get_activation_time(cert);
+
+                printf("\tCertificate is valid since: %s",
+                       ctime(&activation_time));
+                printf("\tCertificate expires: %s",
+                       ctime(&expiration_time));
+
+                /* Print the serial number of the certificate.
+                 */
+                size = sizeof(serial);
+                gnutls_x509_crt_get_serial(cert, serial, &size);
+
+                printf("\tCertificate serial number: %s\n",
+                       bin2hex(serial, size));
+
+                /* Extract some of the public key algorithm's parameters
+                 */
+                algo = gnutls_x509_crt_get_pk_algorithm(cert, &bits);
+
+                printf("Certificate public key: %s",
+                       gnutls_pk_algorithm_get_name(algo));
+
+                /* Print the version of the X.509
+                 * certificate.
+                 */
+                printf("\tCertificate version: #%d\n",
+                       gnutls_x509_crt_get_version(cert));
+
+                size = sizeof(dn);
+                gnutls_x509_crt_get_dn(cert, dn, &size);
+                printf("\tDN: %s\n", dn);
+
+                size = sizeof(dn);
+                gnutls_x509_crt_get_issuer_dn(cert, dn, &size);
+                printf("\tIssuer's DN: %s\n", dn);
+
+                gnutls_x509_crt_deinit(cert);
+
+        }
+}