+static struct slap_control *
+find_ctrl( const char *oid );
+
+/*
+ * Register a supported control.
+ *
+ * This can be called by an OpenLDAP plugin or, indirectly, by a
+ * SLAPI plugin calling slapi_register_supported_control().
+ *
+ * NOTE: if flags == 1 the control is replaced if already registered;
+ * otherwise registering an already registered control is not allowed.
+ */
+int
+register_supported_control2(const char *controloid,
+ slap_mask_t controlmask,
+ char **controlexops,
+ SLAP_CTRL_PARSE_FN *controlparsefn,
+ unsigned flags,
+ int *controlcid)
+{
+ struct slap_control *sc = NULL;
+ int i;
+ BerVarray extendedopsbv = NULL;
+
+ if ( num_known_controls >= SLAP_MAX_CIDS ) {
+ Debug( LDAP_DEBUG_ANY, "Too many controls registered."
+ " Recompile slapd with SLAP_MAX_CIDS defined > %d\n",
+ SLAP_MAX_CIDS, 0, 0 );
+ return LDAP_OTHER;
+ }
+
+ if ( controloid == NULL ) {
+ return LDAP_PARAM_ERROR;
+ }
+
+ /* check if already registered */
+ for ( i = 0; slap_known_controls[ i ]; i++ ) {
+ if ( strcmp( controloid, slap_known_controls[ i ] ) == 0 ) {
+ if ( flags == 1 ) {
+ Debug( LDAP_DEBUG_TRACE,
+ "Control %s already registered; replacing.\n",
+ controloid, 0, 0 );
+ /* (find and) replace existing handler */
+ sc = find_ctrl( controloid );
+ assert( sc != NULL );
+ break;
+ }
+
+ Debug( LDAP_DEBUG_ANY,
+ "Control %s already registered.\n",
+ controloid, 0, 0 );
+ return LDAP_PARAM_ERROR;
+ }
+ }
+
+ /* turn compatible extended operations into bervals */
+ if ( controlexops != NULL ) {
+ int i;
+
+ for ( i = 0; controlexops[ i ]; i++ );
+
+ extendedopsbv = ber_memcalloc( i + 1, sizeof( struct berval ) );
+ if ( extendedopsbv == NULL ) {
+ return LDAP_NO_MEMORY;
+ }
+
+ for ( i = 0; controlexops[ i ]; i++ ) {
+ ber_str2bv( controlexops[ i ], 0, 1, &extendedopsbv[ i ] );
+ }
+ }
+
+ if ( sc == NULL ) {
+ sc = (struct slap_control *)SLAP_MALLOC( sizeof( *sc ) );
+ if ( sc == NULL ) {
+ return LDAP_NO_MEMORY;
+ }
+
+ sc->sc_oid = ch_strdup( controloid );
+ sc->sc_cid = num_known_controls;
+
+ /* Update slap_known_controls, too. */
+ slap_known_controls[num_known_controls - 1] = sc->sc_oid;
+ slap_known_controls[num_known_controls++] = NULL;
+
+ LDAP_SLIST_NEXT( sc, sc_next ) = NULL;
+ LDAP_SLIST_INSERT_HEAD( &controls_list, sc, sc_next );
+
+ } else {
+ if ( sc->sc_extendedopsbv ) {
+ /* FIXME: in principle, we should rather merge
+ * existing extops with those supported by the
+ * new control handling implementation.
+ * In fact, whether a control is compatible with
+ * an extop should not be a matter of implementation.
+ * We likely also need a means for a newly
+ * registered extop to declare that it is
+ * comptible with an already registered control.
+ */
+ ber_bvarray_free( sc->sc_extendedopsbv );
+ sc->sc_extendedopsbv = NULL;
+ sc->sc_extendedops = NULL;
+ }
+ }
+
+ sc->sc_extendedopsbv = extendedopsbv;
+ sc->sc_mask = controlmask;
+ sc->sc_parse = controlparsefn;
+ if ( controlcid ) {
+ *controlcid = sc->sc_cid;
+ }
+
+ return LDAP_SUCCESS;
+}
+
+/*
+ * One-time initialization of internal controls.
+ */
+int
+slap_controls_init( void )
+{
+ int i, rc;
+
+ rc = LDAP_SUCCESS;
+
+ for ( i = 0; control_defs[i].sc_oid != NULL; i++ ) {
+ int *cid = (int *)(((char *)&slap_cids) + control_defs[i].sc_cid );
+ rc = register_supported_control( control_defs[i].sc_oid,
+ control_defs[i].sc_mask, control_defs[i].sc_extendedops,
+ control_defs[i].sc_parse, cid );
+ if ( rc != LDAP_SUCCESS ) break;
+ }
+
+ return rc;
+}
+
+/*
+ * Free memory associated with list of supported controls.
+ */
+void
+controls_destroy( void )
+{
+ struct slap_control *sc;
+
+ while ( !LDAP_SLIST_EMPTY(&controls_list) ) {
+ sc = LDAP_SLIST_FIRST(&controls_list);
+ LDAP_SLIST_REMOVE_HEAD(&controls_list, sc_next);
+
+ ch_free( sc->sc_oid );
+ if ( sc->sc_extendedopsbv != NULL ) {
+ ber_bvarray_free( sc->sc_extendedopsbv );
+ }
+ ch_free( sc );
+ }
+}
+
+/*
+ * Format the supportedControl attribute of the root DSE,
+ * detailing which controls are supported by the directory
+ * server.
+ */
+int
+controls_root_dse_info( Entry *e )