allow creation of subsystems whatever order the databases appear

servers/slapd/back-monitor/back-monitor.h

@@ -46,16 +46,18 @@ struct monitorentrypriv {
 	Entry			*mp_children;	/* pointer to first child */
 	struct monitorsubsys	*mp_info;	/* subsystem info */
 #define mp_type		mp_info->mss_type
-	int			mp_flags;	/* flags */
+	unsigned long		mp_flags;	/* flags */
 
-#define	MONITOR_F_NONE		0x00
-#define MONITOR_F_SUB		0x01		/* subentry of subsystem */
-#define MONITOR_F_PERSISTENT	0x10		/* persistent entry */
-#define MONITOR_F_PERSISTENT_CH	0x20		/* subsystem generates 
+#define	MONITOR_F_NONE		0x00U
+#define MONITOR_F_SUB		0x01U		/* subentry of subsystem */
+#define MONITOR_F_PERSISTENT	0x10U		/* persistent entry */
+#define MONITOR_F_PERSISTENT_CH	0x20U		/* subsystem generates 
 						   persistent entries */
-#define MONITOR_F_VOLATILE	0x40		/* volatile entry */
-#define MONITOR_F_VOLATILE_CH	0x80		/* subsystem generates 
+#define MONITOR_F_VOLATILE	0x40U		/* volatile entry */
+#define MONITOR_F_VOLATILE_CH	0x80U		/* subsystem generates 
 						   volatile entries */
+/* NOTE: flags with 0xF0000000U mask are reserved for subsystem internals */
+
 	int			(*mp_update)( Operation *op, Entry *e );
 						/* update callback
 						   for user-defined entries */
@@ -221,6 +223,7 @@ typedef struct monitorsubsys {
 	struct berval	mss_dn;
 	struct berval	mss_ndn;
 	int		mss_flags;
+#define MONITOR_F_OPENED	0x10000000U
 
 #define MONITOR_HAS_VOLATILE_CH( mp ) \
 	( ( mp )->mp_flags & MONITOR_F_VOLATILE_CH )

servers/slapd/back-monitor/init.c

@@ -36,8 +36,17 @@
  */
 BackendDB *be_monitor = NULL;
 
+static struct monitorsubsys	**monitor_subsys = NULL;
+static int			monitor_subsys_opened = 0;
+
 /*
  * subsystem data
+ *
+ * the known subsystems are added to the subsystems
+ * array at backend initialization; other subsystems
+ * may be added by calling monitor_back_register_subsys()
+ * before the database is opened (e.g. by other backends
+ * or by overlays or modules).
  */
 static struct monitorsubsys known_monitor_subsys[] = {
 	{ 
@@ -163,8 +172,6 @@ init_module( int argc, char *argv[] )
 
 #endif /* SLAPD_MONITOR */
 
-static struct monitorsubsys **monitor_subsys = NULL;
-
 int
 monitor_back_register_subsys( monitorsubsys *ms )
 {
@@ -185,6 +192,22 @@ monitor_back_register_subsys( monitorsubsys *ms )
 	monitor_subsys[ i ] = ms;
 	monitor_subsys[ i + 1 ] = NULL;
 
+	/* if a subsystem is registered __AFTER__ subsystem 
+	 * initialization (depending on the sequence the databases
+	 * are listed in slapd.conf), init it */
+	if ( monitor_subsys_opened ) {
+
+		/* FIXME: this should only be possible
+		 * if be_monitor is already initialized */
+		assert( be_monitor );
+
+		if ( ms->mss_open && ( *ms->mss_open )( be_monitor, ms ) ) {
+			return -1;
+		}
+
+		ms->mss_flags |= MONITOR_F_OPENED;
+	}
+
 	return 0;
 }
 
@@ -679,7 +702,8 @@ monitor_back_db_open(
 	Entry 			*e, **ep;
 	struct monitorentrypriv	*mp;
 	int			i;
-	char 			buf[ BACKMONITOR_BUFSIZE ], *end_of_line;
+	char 			buf[ BACKMONITOR_BUFSIZE ],
+				*end_of_line;
 	struct berval		bv;
 	struct tm		*tms;
 #ifdef HAVE_GMTIME_R
@@ -893,8 +917,11 @@ monitor_back_db_open(
 		{
 			return( -1 );
 		}
+		ms[ 0 ]->mss_flags |= MONITOR_F_OPENED;
 	}
 
+	monitor_subsys_opened = 1;
+
 	return( 0 );
 }