sun4v/snmp/snmpplugin.c

4  * The contents of this file are subject to the terms of the
24  * Use is subject to license terms.
28  * The SNMP picl plugin connects to the agent on the SP and creates
68  * and the 'rebuild_tree' flag below are both initialized to B_TRUE to
77  * to only when the flag is B_TRUE.
94  * rebuild_tree has to be initialized to B_TRUE to let the tree_builder
105  * queue and processes jobs from it to keep cache entries from expiring.  It
106  * attempts to run in cycles of CACHE_REFRESH_CYCLE seconds each, first
111  * NOTE: By using a thread to keep the SNMP cache refreshed in the background,
112  * we are both adding load to the system and reducing the system's ability to
115  * performance, it may be desirable in the future to move this work into the
117  * sun4v config currently available (Batoka), they may need to be revisited for
350 	 * integral to the proper function of the plugin.  If we fail to create
376 	 * since we're about to recycle the plug-in.  No need to worry
393 	/* wake up the tree_builder thread, tell it to exit */
400 	/* send SIGUSR1 to get tree_builder out of a blocked system call */
423 	 * Nothing to do here.
425 	 * system call to return EINTR. This is used to trigger early exit from
427 	 * would be required to allow early exit if the tree builder thread is
443 	 * catch SIGUSR1 to allow early exit from snmp_init which may block
480 		LOGPRINTF("tree_builder: check whether to rebuild subtree\n");
488 			LOGPRINTF("tree_builder: time to exit\n");
534 		LOGPRINTF("tree_builder: setting stale_tree to FALSE\n");
539 		LOGPRINTF("tree_builder: setting rebuild_tree to FALSE\n");
596 			 * happened and we need to throw away everything
713 	 * created first; if there's no parent, then parent it to the
1022  * doing this in response to a hotplug event, we should've freed the
1023  * old physplat_nodes before entering here to save the first node of the
1067  * subtree, whether for the first time or in response to a hotplug event.
1069  * to be B_TRUE, so no one else would be accessing vol_props, n_vol_props
1070  * or volprop_ndx. If we're here to build the tree for the first time,
1117 	 * Check if some other thread beat us to it
1125 	 * Cache OID_entLastChangeTime for up to 10 seconds before
1150 	 * If we can't read entLastChangeTime we assume we need to rebuild
1151 	 * the tree. This will also cover the case when we need to rebuild
1158 	 * If the mib data has changed, we need to rebuild the physical-platform
1159 	 * subtree. To do this, we set a flag to mark the tree stale,
1160 	 * so that any future reads to get value of volatile properties will
1183  * it needs to fetch the value of a volatile property. The first thing we
1184  * must do, however, is to see if there has been a hotplug or a link-reset
1185  * event since the last time we built the tree and whether we need to
1186  * rebuild the tree. If so, we do whatever is necessary to make that happen,
1228 	 * due to a link reset, between the check for stale data and now,
1430 	 * This mask prevents us from attempting to fetch thresholds
1431 	 * which don't apply to the sensor or that aren't there anyway,
1433 	 * takes several seconds to time out.
1441 		 * The ALOM snmp agent doesn't adhere to the BER rules for
1552  * Add the specified string property to the node
1581  * Add the specified void property to the node
1903  * process refresh job to prevent cache entries from expiring.
1911 	timestruc_t	to;
1931 		 * 1) we are told to exit, or
1951 		 * As long as we haven't been told to exit, sleep for
1954 		 * equal to or greater than 60 seconds, skip sleeping entirely.
1959 			to.tv_sec = CACHE_REFRESH_CYCLE - cycle_elapsed;
1960 			to.tv_nsec = 0;
1962 			    &cache_refresh_lock, &to);
1966 		 * If we have been told to exit, clean up and bail out.
1971 			LOGPRINTF("cache_refresher: time to exit\n");
1982  * Check to see if the cache_refresher thread is running.  If it is, signal it
1983  * to terminate and clean up associated data structures.
1988 	/* if the thread isn't running, there is nothing to do */
1992 	/* wake up the cache_refresher thread, tell it to exit */