From 1a217516f07a2e09a2dafa2807e97ed09909f10a Mon Sep 17 00:00:00 2001
From: Pierangelo Masarati <ando@openldap.org>
Date: Wed, 11 Jan 2006 19:36:18 +0000
Subject: [PATCH] allow control handlers to be replaced

---
 servers/slapd/controls.c   | 79 ++++++++++++++++++++++++++------------
 servers/slapd/proto-slap.h |  5 ++-
 2 files changed, 59 insertions(+), 25 deletions(-)

diff --git a/servers/slapd/controls.c b/servers/slapd/controls.c
index 1e768bd11b..426b9cb02c 100644
--- a/servers/slapd/controls.c
+++ b/servers/slapd/controls.c
@@ -197,21 +197,29 @@ static struct slap_control control_defs[] = {
 	{ NULL, 0, 0, NULL, 0, LDAP_SLIST_ENTRY_INITIALIZER(next) }
 };
 
+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_control(const char *controloid,
+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;
+	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."
@@ -220,11 +228,23 @@ register_supported_control(const char *controloid,
 		return LDAP_OTHER;
 	}
 
-	if ( controloid == NULL ) return LDAP_PARAM_ERROR;
+	if ( controloid == NULL ) {
+		return LDAP_PARAM_ERROR;
+	}
 
-	/* sanity check - should never happen */
+	/* 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 );
@@ -232,41 +252,52 @@ register_supported_control(const char *controloid,
 		}
 	}
 
-	sc = (struct slap_control *)SLAP_MALLOC( sizeof( *sc ) );
-	if ( sc == NULL ) return LDAP_NO_MEMORY;
-
-	sc->sc_oid = ch_strdup( controloid );
-	sc->sc_mask = controlmask;
+	/* turn compatible extended operations into bervals */
 	if ( controlexops != NULL ) {
 		int i;
 
 		for ( i = 0; controlexops[ i ]; i++ );
 
-		sc->sc_extendedopsbv = ber_memcalloc( i + 1, sizeof( struct berval ) );
-		if ( sc->sc_extendedopsbv == NULL ) {
-			ch_free( sc );
+		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, &sc->sc_extendedopsbv[ 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 {
-		sc->sc_extendedopsbv = NULL;
+		if ( sc->sc_extendedopsbv ) {
+			ber_bvarray_free( sc->sc_extendedops );
+			sc->sc_extendedops = NULL;
+		}
 	}
-	sc->sc_extendedops = NULL;
-	sc->sc_parse = controlparsefn;
-
-	if ( controlcid ) *controlcid = num_known_controls;
-	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;
+	sc->sc_extendedopsbv = extendedopsbv;
+	sc->sc_mask = controlmask;
+	sc->sc_parse = controlparsefn;
+	if ( controlcid ) {
+		*controlcid = sc->sc_cid;
+	}
 
-	LDAP_SLIST_NEXT( sc, sc_next ) = NULL;
-	LDAP_SLIST_INSERT_HEAD( &controls_list, sc, sc_next );
 	return LDAP_SUCCESS;
 }
 
diff --git a/servers/slapd/proto-slap.h b/servers/slapd/proto-slap.h
index eae7835fa6..41ddfe1804 100644
--- a/servers/slapd/proto-slap.h
+++ b/servers/slapd/proto-slap.h
@@ -558,12 +558,15 @@ LDAP_SLAPD_F (int) get_ctrls LDAP_P((
 	Operation *op,
 	SlapReply *rs,
 	int senderrors ));
-LDAP_SLAPD_F (int) register_supported_control LDAP_P((
+LDAP_SLAPD_F (int) register_supported_control2 LDAP_P((
 	const char *controloid,
 	slap_mask_t controlmask,
 	char **controlexops,
 	SLAP_CTRL_PARSE_FN *controlparsefn,
+	unsigned flags,
 	int *controlcid ));
+#define register_supported_control(oid, mask, exops, fn, cid) \
+	register_supported_control2((oid), (mask), (exops), (fn), 0, (cid))
 LDAP_SLAPD_F (int) slap_controls_init LDAP_P ((void));
 LDAP_SLAPD_F (void) controls_destroy LDAP_P ((void));
 LDAP_SLAPD_F (int) controls_root_dse_info LDAP_P ((Entry *e));
-- 
2.39.5