krb5_db_lock
if (krb5_db_lock(util_context, KRB5_LOCKMODE_SHARED)) {
if ((kret = krb5_db_lock(kcontext, update?KRB5_DB_LOCKMODE_PERMANENT: KRB5_DB_LOCKMODE_EXCLUSIVE))) {
krb5_error_code krb5_db_lock ( krb5_context kcontext, int lock_mode );
ret = krb5_db_lock(handle->context, KRB5_DB_LOCKMODE_EXCLUSIVE);
retval = krb5_db_lock(context, KRB5_LOCKMODE_SHARED);