xref: /illumos-gate/usr/src/cmd/fm/fmd/common/fmd_dr.c (revision a07094369b21309434206d9b3601d162693466fc)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * FMD Dynamic Reconfiguration (DR) Event Handling
31  *
32  * Fault manager scheme plug-ins must track characteristics of individual
33  * pieces of hardware.  As these components can be added or removed by a DR
34  * operation, we need to provide a means by which plug-ins can determine when
35  * they need to re-examine the current configuration.  We provide a simple
36  * mechanism whereby this task can be implemented using lazy evaluation: a
37  * simple 64-bit generation counter is maintained and incremented on *any* DR.
38  * Schemes can store the generation number in scheme-specific data structures,
39  * and then revalidate their contents if the current generation number has
40  * changed since the resource information was cached.  This method saves time,
41  * avoids the complexity of direct participation in DR, avoids the need for
42  * resource-specific processing of DR events, and is relatively easy to port
43  * to other systems that support dynamic reconfiguration.
44  */
45 
46 #include <sys/types.h>
47 #include <sys/sysevent/dr.h>
48 #include <sys/sysevent/eventdefs.h>
49 
50 #include <stdio.h>
51 #include <unistd.h>
52 #include <libsysevent.h>
53 
54 #undef MUTEX_HELD
55 #undef RW_READ_HELD
56 #undef RW_WRITE_HELD
57 
58 #include <fmd_error.h>
59 #include <fmd_subr.h>
60 #include <fmd.h>
61 
62 static void
63 fmd_dr_event(sysevent_t *sep)
64 {
65 	uint64_t gen;
66 
67 	(void) pthread_mutex_lock(&fmd.d_stats_lock);
68 	gen = fmd.d_stats->ds_dr_gen.fmds_value.ui64++;
69 	(void) pthread_mutex_unlock(&fmd.d_stats_lock);
70 
71 	TRACE((FMD_DBG_XPRT, "dr event %p, gen=%llu", (void *)sep, gen));
72 }
73 
74 void
75 fmd_dr_init(void)
76 {
77 	const char *subclass = ESC_DR_AP_STATE_CHANGE;
78 
79 	if (geteuid() != 0)
80 		return; /* legacy sysevent mechanism is still root-only */
81 
82 	if ((fmd.d_dr_hdl = sysevent_bind_handle(fmd_dr_event)) == NULL)
83 		fmd_error(EFMD_EXIT, "failed to bind handle for DR sysevent");
84 
85 	if (sysevent_subscribe_event(fmd.d_dr_hdl, EC_DR, &subclass, 1) == -1)
86 		fmd_error(EFMD_EXIT, "failed to subscribe for DR sysevent");
87 }
88 
89 void
90 fmd_dr_fini(void)
91 {
92 	if (fmd.d_dr_hdl != NULL) {
93 		sysevent_unsubscribe_event(fmd.d_dr_hdl, EC_DR);
94 		sysevent_unbind_handle(fmd.d_dr_hdl);
95 	}
96 }
97