ITS#10308 Implement cn=monitor for back-asyncmeta

Provide some target connection statistics such as target connections
status and target status

servers/slapd/back-asyncmeta/Makefile.in

@@ -21,10 +21,10 @@
 
 SRCS	= init.c config.c search.c message_queue.c bind.c add.c compare.c \
 		delete.c modify.c modrdn.c map.c \
-		conn.c candidates.c dncache.c meta_result.c
+		conn.c candidates.c dncache.c meta_result.c monitor.c
 OBJS	= init.lo config.lo search.lo message_queue.lo bind.lo add.lo compare.lo \
 		delete.lo modify.lo modrdn.lo map.lo \
-		conn.lo candidates.lo dncache.lo meta_result.lo
+		conn.lo candidates.lo dncache.lo meta_result.lo monitor.lo
 
 LDAP_INCDIR= ../../../include
 LDAP_LIBDIR= ../../../libraries

servers/slapd/back-asyncmeta/back-asyncmeta.h

@@ -168,6 +168,8 @@ typedef struct a_metaconn_t {
 	struct a_metainfo_t	*mc_info;
 
 	int pending_ops;
+	/* numeric id for logging and testing purposes */
+	int mc_id;
 	ldap_pvt_thread_mutex_t	mc_om_mutex;
 	/* queue for pending operations */
 	LDAP_STAILQ_HEAD(BCList, bm_context_t) mc_om_list;
@@ -358,6 +360,15 @@ typedef int (*asyncmeta_quarantine_f)( struct a_metainfo_t *, int target, void *
 
 struct meta_out_message_t;
 
+/* data for cn=monitor */
+typedef struct asyncmeta_monitor_info_t {
+	monitor_subsys_t	*mi_conn_mss;
+	monitor_subsys_t    *mi_targets_mss;
+	struct berval		mi_ndn;
+	struct berval		mi_conn_rdn;
+	struct berval		mi_targets_rdn;
+} asycnmeta_monitor_info_t;
+
 typedef struct a_metainfo_t {
 	int			mi_ntargets;
 	int			mi_defaulttarget;
@@ -420,6 +431,8 @@ typedef struct a_metainfo_t {
 	int                    mi_max_timeout_ops;
 	int                    mi_max_pending_ops;
 	int                    mi_max_target_conns;
+
+	asycnmeta_monitor_info_t mi_monitor_info;
 	/* mutex for access to the connection structures */
 	ldap_pvt_thread_mutex_t	mi_mc_mutex;
 	int                    mi_num_conns;
@@ -784,6 +797,19 @@ asyncmeta_target_free(a_metatarget_t *mt);
 void
 asyncmeta_back_clear_miconns(a_metainfo_t *mi);
 
+/* cn=monitor */
+int
+asyncmeta_back_monitor_db_init( BackendDB *be );
+
+int
+asyncmeta_back_monitor_db_open( BackendDB *be );
+
+int
+asyncmeta_back_monitor_db_close( BackendDB *be );
+
+int
+asyncmeta_back_monitor_db_destroy( BackendDB *be );
+
 /* The the maximum time in seconds after a result has been received on a connection,
  * after which it can be reset if a sender error occurs. Should this be configurable? */
 #define META_BACK_RESULT_INTERVAL (2)

servers/slapd/back-asyncmeta/init.c

@@ -160,12 +160,15 @@ asyncmeta_back_db_init(
 	mi->mi_conn_priv_max = LDAP_BACK_CONN_PRIV_DEFAULT;
 
 	mi->mi_ldap_extra = (ldap_extra_t *)bi->bi_extra;
+	/* only so that the first chosen connection is the first in the
+	   array, for test purposes */
+	mi->mi_next_conn = -1;
 	ldap_pvt_thread_mutex_init( &mi->mi_mc_mutex);
 
 	be->be_private = mi;
 	be->be_cf_ocs = be->bd_info->bi_cf_ocs;
 
-	return 0;
+	return asyncmeta_back_monitor_db_init( be );
 }
 
 int
@@ -262,6 +265,7 @@ asyncmeta_back_db_open(
 		for (i = 0; i < mi->mi_num_conns; i++) {
 			a_metaconn_t *mc = &mi->mi_conns[i];
 			ldap_pvt_thread_mutex_init( &mc->mc_om_mutex);
+			mc->mc_id = i+1;
 			mc->mc_authz_target = META_BOUND_NONE;
 
 			if ( mi->mi_ntargets > 0 ) {
@@ -284,7 +288,8 @@ asyncmeta_back_db_open(
 			ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
 		}
 	}
-	return 0;
+
+	return asyncmeta_back_monitor_db_open( be );
 }
 
 /*
@@ -410,7 +415,7 @@ asyncmeta_back_db_close(
 				}
 		}
 	}
-	return 0;
+	return asyncmeta_back_monitor_db_close( be );
 }
 
 int
@@ -419,7 +424,7 @@ asyncmeta_back_db_destroy(
 	ConfigReply	*cr )
 {
 	a_metainfo_t	*mi;
-
+	int rc = 0;
 	if ( be->be_private ) {
 		int i;
 
@@ -467,10 +472,10 @@ asyncmeta_back_db_destroy(
 		asyncmeta_back_clear_miconns(mi);
 		ldap_pvt_thread_mutex_unlock( &mi->mi_mc_mutex );
 		ldap_pvt_thread_mutex_destroy( &mi->mi_mc_mutex );
-
+		rc = asyncmeta_back_monitor_db_destroy( be );
 		free( be->be_private );
 	}
-	return 0;
+	return rc;
 }
 
 #if SLAPD_ASYNCMETA == SLAPD_MOD_DYNAMIC