xref: /titanic_41/usr/src/cmd/fm/fmd/common/fmd_dr.c (revision 4496171313bed39e96f21bc2f9faf2868e267ae3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 /*
29  * FMD Dynamic Reconfiguration (DR) Event Handling
30  *
31  * Fault manager scheme plug-ins must track characteristics of individual
32  * pieces of hardware.  As these components can be added or removed by a DR
33  * operation, we need to provide a means by which plug-ins can determine when
34  * they need to re-examine the current configuration.  We provide a simple
35  * mechanism whereby this task can be implemented using lazy evaluation: a
36  * simple 64-bit generation counter is maintained and incremented on *any* DR.
37  * Schemes can store the generation number in scheme-specific data structures,
38  * and then revalidate their contents if the current generation number has
39  * changed since the resource information was cached.  This method saves time,
40  * avoids the complexity of direct participation in DR, avoids the need for
41  * resource-specific processing of DR events, and is relatively easy to port
42  * to other systems that support dynamic reconfiguration.
43  */
44 
45 #include <sys/types.h>
46 #include <sys/sysevent/dr.h>
47 #include <sys/sysevent/eventdefs.h>
48 
49 #include <stdio.h>
50 #include <unistd.h>
51 #include <libsysevent.h>
52 
53 #undef MUTEX_HELD
54 #undef RW_READ_HELD
55 #undef RW_WRITE_HELD
56 
57 #include <fmd_asru.h>
58 #include <fmd_error.h>
59 #include <fmd_fmri.h>
60 #include <fmd_subr.h>
61 #include <fmd.h>
62 
63 static void
64 fmd_dr_repair_containee(fmd_asru_t *ee, void *er)
65 {
66 	if ((ee->asru_flags & FMD_ASRU_FAULTY) &&
67 	    fmd_fmri_contains(er, ee->asru_fmri) > 0)
68 		(void) fmd_asru_clrflags(ee, FMD_ASRU_FAULTY, NULL, NULL);
69 }
70 
71 /*ARGSUSED*/
72 static void
73 fmd_dr_rcache_sync(fmd_asru_t *ap, void *arg)
74 {
75 	if (fmd_fmri_present(ap->asru_fmri) != 0)
76 		return;
77 
78 	if (!fmd_asru_clrflags(ap, FMD_ASRU_FAULTY, NULL, NULL))
79 		return;
80 
81 	/*
82 	 * We've located the requested ASRU, and have repaired it.  Now
83 	 * traverse the ASRU cache, looking for any faulty entries that
84 	 * are contained by this one.  If we find any, repair them too.
85 	 */
86 	fmd_asru_hash_apply(fmd.d_asrus, fmd_dr_repair_containee,
87 	    ap->asru_fmri);
88 }
89 
90 static void
91 fmd_dr_event(sysevent_t *sep)
92 {
93 	uint64_t gen;
94 
95 	/*
96 	 * If the event target is in the R$ and this sysevent indicates it was
97 	 * removed, remove it from the R$ also.
98 	 */
99 	(void) fmd_asru_hash_apply(fmd.d_asrus, fmd_dr_rcache_sync, NULL);
100 
101 	(void) pthread_mutex_lock(&fmd.d_stats_lock);
102 	gen = fmd.d_stats->ds_dr_gen.fmds_value.ui64++;
103 	(void) pthread_mutex_unlock(&fmd.d_stats_lock);
104 
105 	TRACE((FMD_DBG_XPRT, "dr event %p, gen=%llu", (void *)sep, gen));
106 }
107 
108 void
109 fmd_dr_init(void)
110 {
111 	const char *subclass = ESC_DR_AP_STATE_CHANGE;
112 
113 	if (geteuid() != 0)
114 		return; /* legacy sysevent mechanism is still root-only */
115 
116 	if ((fmd.d_dr_hdl = sysevent_bind_handle(fmd_dr_event)) == NULL)
117 		fmd_error(EFMD_EXIT, "failed to bind handle for DR sysevent");
118 
119 	if (sysevent_subscribe_event(fmd.d_dr_hdl, EC_DR, &subclass, 1) == -1)
120 		fmd_error(EFMD_EXIT, "failed to subscribe for DR sysevent");
121 }
122 
123 void
124 fmd_dr_fini(void)
125 {
126 	if (fmd.d_dr_hdl != NULL) {
127 		sysevent_unsubscribe_event(fmd.d_dr_hdl, EC_DR);
128 		sysevent_unbind_handle(fmd.d_dr_hdl);
129 	}
130 }
131