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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* FMD Control Event Subsystem
*
* This file provides a simple and extensible subsystem for the processing of
* synchronous control events that can be received from the event transport
* and used to control the behavior of the fault manager itself. At present
* this feature is used for the implementation of simulation controls such as
* advancing the simulated clock using events sent by the fminject utility.
* Control events are assigned a class of the form "resource.fm.fmd.*" and
* are assigned a callback function defined in the _fmd_ctls[] table below.
* As control events are received by the event transport, they are assigned a
* special event type (ev_type = FMD_EVT_CTL) and the ev_data member is used
* to refer to a fmd_ctl_t data structure, managed by the functions below.
*
* Control events are implemented so that they are synchronous with respect to
* the rest of the fault manager event stream, which is usually asynchronous
* (that is, the transport dispatch thread and the module receive threads all
* execute in parallel). Synchronous processing is required for control events
* so that they can affect global state (e.g. the simulated clock) and ensure
* that the results of any state changes are seen by *all* subsequent events.
*
* To achieve synchronization, the event itself implements a thread barrier:
* the fmd_ctl_t maintains a reference count that mirrors the fmd_event_t
* reference count (which for ctls counts the number of modules the event
* was dispatched to). As each module receive thread dequeues the event, it
* calls fmd_event_rele() to discard the event, which calls fmd_ctl_rele().
* fmd_ctl_rele() decrements the ctl's reference count but blocks there waiting
* for *all* other references to be released. When all threads have reached
* the barrier, the final caller of fmd_ctl_rele() executes the control event
* callback function and then wakes everyone else up. The transport dispatch
* thread, blocked in fmd_modhash_dispatch(), is typically this final caller.
*/
#include <strings.h>
#include <limits.h>
#include <signal.h>
#include <fmd_protocol.h>
#include <fmd_alloc.h>
#include <fmd_error.h>
#include <fmd_subr.h>
#include <fmd_time.h>
#include <fmd_module.h>
#include <fmd_thread.h>
#include <fmd_ctl.h>
#include <fmd.h>
static void
fmd_ctl_addhrt(nvlist_t *nvl)
{
int64_t delta = 0;
(void) nvlist_lookup_int64(nvl, FMD_CTL_ADDHRT_DELTA, &delta);
fmd_time_addhrtime(delta);
/*
* If the non-adjustable clock has reached the apocalypse, fmd(8)
* should exit gracefully: queue a SIGTERM for the main thread.
*/
if (fmd_time_gethrtime() == INT64_MAX)
(void) pthread_kill(fmd.d_rmod->mod_thread->thr_tid, SIGTERM);
}
static void
fmd_ctl_inval(nvlist_t *nvl)
{
char *class = "<unknown>";
(void) nvlist_lookup_string(nvl, FM_CLASS, &class);
fmd_error(EFMD_CTL_INVAL, "ignoring invalid control event %s\n", class);
}
/*ARGSUSED*/
static void
fmd_ctl_pause(nvlist_t *nvl)
{
fmd_dprintf(FMD_DBG_DISP, "unpausing modules from ctl barrier\n");
}
static const fmd_ctl_desc_t _fmd_ctls[] = {
{ FMD_CTL_ADDHRT, FMD_CTL_ADDHRT_VERS1, fmd_ctl_addhrt },
{ NULL, UINT_MAX, fmd_ctl_inval }
};
fmd_ctl_t *
fmd_ctl_init(nvlist_t *nvl)
{
fmd_ctl_t *cp = fmd_alloc(sizeof (fmd_ctl_t), FMD_SLEEP);
const fmd_ctl_desc_t *dp;
uint8_t vers;
char *class;
(void) pthread_mutex_init(&cp->ctl_lock, NULL);
(void) pthread_cond_init(&cp->ctl_cv, NULL);
cp->ctl_nvl = nvl;
cp->ctl_refs = 0;
if (nvl == NULL) {
cp->ctl_func = fmd_ctl_pause;
return (cp);
}
if (nvlist_lookup_string(nvl, FM_CLASS, &class) != 0 ||
nvlist_lookup_uint8(nvl, FM_VERSION, &vers) != 0)
fmd_panic("ctl_init called with bad nvlist %p", (void *)nvl);
for (dp = _fmd_ctls; dp->cde_class != NULL; dp++) {
if (strcmp(class, dp->cde_class) == 0)
break;
}
cp->ctl_func = vers > dp->cde_vers ? &fmd_ctl_inval : dp->cde_func;
return (cp);
}
void
fmd_ctl_fini(fmd_ctl_t *cp)
{
fmd_free(cp, sizeof (fmd_ctl_t));
}
/*
* Increment the ref count on the fmd_ctl_t to correspond to a reference to the
* fmd_event_t. This count is used to implement a barrier in fmd_ctl_rele().
*/
void
fmd_ctl_hold(fmd_ctl_t *cp)
{
(void) pthread_mutex_lock(&cp->ctl_lock);
cp->ctl_refs++;
ASSERT(cp->ctl_refs != 0);
(void) pthread_mutex_unlock(&cp->ctl_lock);
}
/*
* Decrement the reference count on the fmd_ctl_t. If this rele() is the last
* one, then execute the callback function and release all the other callers.
* Otherwise enter a loop waiting on ctl_cv for other threads to call rele().
*/
void
fmd_ctl_rele(fmd_ctl_t *cp)
{
(void) pthread_mutex_lock(&cp->ctl_lock);
ASSERT(cp->ctl_refs != 0);
cp->ctl_refs--;
if (cp->ctl_refs == 0) {
cp->ctl_func(cp->ctl_nvl);
(void) pthread_cond_broadcast(&cp->ctl_cv);
} else {
while (cp->ctl_refs != 0)
(void) pthread_cond_wait(&cp->ctl_cv, &cp->ctl_lock);
}
(void) pthread_mutex_unlock(&cp->ctl_lock);
}
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