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/*
* Copyright (c) 2004, 2005 Christophe Varoqui
* Copyright (c) 2005 Kiyoshi Ueda, NEC
* Copyright (c) 2005 Benjamin Marzinski, Redhat
* Copyright (c) 2005 Edward Goggin, EMC
*/
#include <unistd.h>
#include <libdevmapper.h>
#include <sys/mman.h>
#include <pthread.h>
#include <signal.h>
#include "vector.h"
#include "memory.h"
#include "checkers.h"
#include "structs.h"
#include "structs_vec.h"
#include "devmapper.h"
#include "debug.h"
#include "lock.h"
#include "waiter.h"
pthread_attr_t waiter_attr;
struct event_thread *alloc_waiter (void)
{
struct event_thread *wp;
wp = (struct event_thread *)MALLOC(sizeof(struct event_thread));
return wp;
}
void free_waiter (void *data)
{
sigset_t old;
struct event_thread *wp = (struct event_thread *)data;
/*
* indicate in mpp that the wp is already freed storage
*/
block_signal(SIGHUP, &old);
lock(wp->vecs->lock);
if (wp->mpp)
/*
* be careful, mpp may already be freed -- null if so
*/
wp->mpp->waiter = NULL;
else
/*
* This is OK condition during shutdown.
*/
condlog(3, "free_waiter, mpp freed before wp=%p (%s).", wp, wp->mapname);
unlock(wp->vecs->lock);
pthread_sigmask(SIG_SETMASK, &old, NULL);
if (wp->dmt)
dm_task_destroy(wp->dmt);
FREE(wp);
}
void stop_waiter_thread (struct multipath *mpp, struct vectors *vecs)
{
struct event_thread *wp = (struct event_thread *)mpp->waiter;
pthread_t thread;
if (!wp) {
condlog(3, "%s: no waiter thread", mpp->alias);
return;
}
thread = wp->thread;
condlog(2, "%s: stop event checker thread (%lu)", wp->mapname, thread);
pthread_kill(thread, SIGUSR1);
}
static sigset_t unblock_signals(void)
{
sigset_t set, old;
sigemptyset(&set);
sigaddset(&set, SIGHUP);
sigaddset(&set, SIGUSR1);
pthread_sigmask(SIG_UNBLOCK, &set, &old);
return old;
}
/*
* returns the reschedule delay
* negative means *stop*
*/
int waiteventloop (struct event_thread *waiter)
{
sigset_t set;
int event_nr;
int r;
if (!waiter->event_nr)
waiter->event_nr = dm_geteventnr(waiter->mapname);
if (!(waiter->dmt = dm_task_create(DM_DEVICE_WAITEVENT))) {
condlog(0, "%s: devmap event #%i dm_task_create error",
waiter->mapname, waiter->event_nr);
return 1;
}
if (!dm_task_set_name(waiter->dmt, waiter->mapname)) {
condlog(0, "%s: devmap event #%i dm_task_set_name error",
waiter->mapname, waiter->event_nr);
dm_task_destroy(waiter->dmt);
return 1;
}
if (waiter->event_nr && !dm_task_set_event_nr(waiter->dmt,
waiter->event_nr)) {
condlog(0, "%s: devmap event #%i dm_task_set_event_nr error",
waiter->mapname, waiter->event_nr);
dm_task_destroy(waiter->dmt);
return 1;
}
dm_task_no_open_count(waiter->dmt);
/* accept wait interruption */
set = unblock_signals();
/* wait */
r = dm_task_run(waiter->dmt);
/* wait is over : event or interrupt */
pthread_sigmask(SIG_SETMASK, &set, NULL);
if (!r) /* wait interrupted by signal */
return -1;
dm_task_destroy(waiter->dmt);
waiter->dmt = NULL;
waiter->event_nr++;
/*
* upon event ...
*/
while (1) {
condlog(3, "%s: devmap event #%i",
waiter->mapname, waiter->event_nr);
/*
* event might be :
*
* 1) a table reload, which means our mpp structure is
* obsolete : refresh it through update_multipath()
* 2) a path failed by DM : mark as such through
* update_multipath()
* 3) map has gone away : stop the thread.
* 4) a path reinstate : nothing to do
* 5) a switch group : nothing to do
*/
pthread_cleanup_push(cleanup_lock, &waiter->vecs->lock);
lock(waiter->vecs->lock);
r = update_multipath(waiter->vecs, waiter->mapname);
lock_cleanup_pop(waiter->vecs->lock);
if (r) {
condlog(2, "%s: event checker exit",
waiter->mapname);
return -1; /* stop the thread */
}
event_nr = dm_geteventnr(waiter->mapname);
if (waiter->event_nr == event_nr)
return 1; /* upon problem reschedule 1s later */
waiter->event_nr = event_nr;
}
return -1; /* never reach there */
}
void *waitevent (void *et)
{
int r;
struct event_thread *waiter;
mlockall(MCL_CURRENT | MCL_FUTURE);
waiter = (struct event_thread *)et;
pthread_cleanup_push(free_waiter, et);
block_signal(SIGUSR1, NULL);
block_signal(SIGHUP, NULL);
while (1) {
r = waiteventloop(waiter);
if (r < 0)
break;
sleep(r);
}
pthread_cleanup_pop(1);
return NULL;
}
int start_waiter_thread (struct multipath *mpp, struct vectors *vecs)
{
struct event_thread *wp;
if (!mpp)
return 0;
wp = alloc_waiter();
if (!wp)
goto out;
mpp->waiter = (void *)wp;
strncpy(wp->mapname, mpp->alias, WWID_SIZE);
wp->vecs = vecs;
wp->mpp = mpp;
if (pthread_create(&wp->thread, &waiter_attr, waitevent, wp)) {
condlog(0, "%s: cannot create event checker", wp->mapname);
goto out1;
}
condlog(2, "%s: event checker started", wp->mapname);
return 0;
out1:
free_waiter(wp);
mpp->waiter = NULL;
out:
condlog(0, "failed to start waiter thread");
return 1;
}
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