Bug 1486699: get_new_username() truncating username badly for SAML

Ends up with username in auth_remote_user being different to the
username in usr table.

behatnotneeded

Change-Id: If6a5a18360ef82da2e3a709899e7d4d1624e8fab
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit dc3b3292)

htdocs/auth/saml/lib.php

@@ -183,7 +183,7 @@ class AuthSaml extends Auth {
             $user->authinstance       = empty($this->config['parent']) ? $this->instanceid : $this->parent;
 
             db_begin();
-            $user->username           = get_new_username($remoteuser);
+            $user->username           = get_new_username($remoteuser, 40);
 
             $user->id = create_user($user, array(), $institutionname, $this, $remoteuser);
 

htdocs/lib/user.php

@@ -1683,9 +1683,9 @@ function load_user_institutions($userid) {
  * Return a username which isn't taken and which is similar to a desired username
  *
  * @param string $desired
+ * @param string $maxlen    Maximum length of desired username
  */
-function get_new_username($desired) {
-    $maxlen = 30;
+function get_new_username($desired, $maxlen=30) {
     if (function_exists('mb_strtolower')) {
         $desired = mb_strtolower(mb_substr($desired, 0, $maxlen, 'UTF-8'), 'UTF-8');
     }