Set default kerberos realm as preferred realm by default.

Signed-off-by: Lukas Hejtmanek <xhejtman@ics.muni.cz>

diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c
index c7f9bdd..3c8c24b 100644
--- a/utils/gssd/gssd.c
+++ b/utils/gssd/gssd.c
@@ -148,6 +148,9 @@ main(int argc, char *argv[])
 		}
 	}
 
+	if(!preferred_realm)
+		preferred_realm = gssd_k5_get_default_realm();
+
 	i = 0;
 	ccachesearch[i++] = strtok(ccachedir, ":");
 	do {
diff --git a/utils/gssd/krb5_util.c b/utils/gssd/krb5_util.c
index 4915293..16d155a 100644
--- a/utils/gssd/krb5_util.c
+++ b/utils/gssd/krb5_util.c
@@ -1234,3 +1234,26 @@ gssd_k5_err_msg(krb5_context context, krb5_error_code code)
 		return error_message(code);
 #endif
 }
+
+/*
+ * Routine that returns default kerberos realm
+ */
+
+const char*
+gssd_k5_get_default_realm()
+{
+	krb5_context context;
+	char         *realm;
+
+	if(krb5_init_context(&context)) {
+		return NULL;
+	}
+
+	if(krb5_get_default_realm(context, &realm)) {
+		krb5_free_context(context);
+		return NULL;
+	}
+
+	krb5_free_context(context);
+	return realm;
+}
diff --git a/utils/gssd/krb5_util.h b/utils/gssd/krb5_util.h
index addae1c..a4cccac 100644
--- a/utils/gssd/krb5_util.h
+++ b/utils/gssd/krb5_util.h
@@ -17,6 +17,7 @@ struct gssd_k5_kt_princ {
 };
 
 
+const char* gssd_k5_get_default_realm(void);
 int gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername,
 				     char *dirname);
 int  gssd_get_krb5_machine_cred_list(char ***list);