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/*
Unix SMB/CIFS implementation.
common events code for timed events
Copyright (C) Andrew Tridgell 2003-2006
Copyright (C) Stefan Metzmacher 2005
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "replace.h"
#include "system/time.h"
#include "tevent.h"
#include "tevent_internal.h"
#include "tevent_util.h"
/**
compare two timeval structures.
Return -1 if tv1 < tv2
Return 0 if tv1 == tv2
Return 1 if tv1 > tv2
*/
static int ev_timeval_compare(const struct timeval *tv1, const struct timeval *tv2)
{
if (tv1->tv_sec > tv2->tv_sec) return 1;
if (tv1->tv_sec < tv2->tv_sec) return -1;
if (tv1->tv_usec > tv2->tv_usec) return 1;
if (tv1->tv_usec < tv2->tv_usec) return -1;
return 0;
}
/**
return a zero timeval
*/
static struct timeval ev_timeval_zero(void)
{
struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 0;
return tv;
}
/**
return a timeval for the current time
*/
static struct timeval ev_timeval_current(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return tv;
}
/**
return a timeval struct with the given elements
*/
static struct timeval ev_timeval_set(uint32_t secs, uint32_t usecs)
{
struct timeval tv;
tv.tv_sec = secs;
tv.tv_usec = usecs;
return tv;
}
/**
return the difference between two timevals as a timeval
if tv1 comes after tv2, then return a zero timeval
(this is *tv2 - *tv1)
*/
static struct timeval ev_timeval_until(const struct timeval *tv1,
const struct timeval *tv2)
{
struct timeval t;
if (ev_timeval_compare(tv1, tv2) >= 0) {
return ev_timeval_zero();
}
t.tv_sec = tv2->tv_sec - tv1->tv_sec;
if (tv1->tv_usec > tv2->tv_usec) {
t.tv_sec--;
t.tv_usec = 1000000 - (tv1->tv_usec - tv2->tv_usec);
} else {
t.tv_usec = tv2->tv_usec - tv1->tv_usec;
}
return t;
}
/**
return true if a timeval is zero
*/
bool ev_timeval_is_zero(const struct timeval *tv)
{
return tv->tv_sec == 0 && tv->tv_usec == 0;
}
/*
destroy a timed event
*/
static int common_event_timed_destructor(struct tevent_timer *te)
{
struct tevent_context *ev = talloc_get_type(te->event_ctx,
struct tevent_context);
DLIST_REMOVE(ev->timer_events, te);
return 0;
}
static int common_event_timed_deny_destructor(struct tevent_timer *te)
{
return -1;
}
/*
add a timed event
return NULL on failure (memory allocation error)
*/
struct tevent_timer *common_event_add_timed(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
struct timeval next_event,
event_timed_handler_t handler,
void *private_data)
{
struct tevent_timer *te, *last_te, *cur_te;
te = talloc(mem_ctx?mem_ctx:ev, struct tevent_timer);
if (te == NULL) return NULL;
te->event_ctx = ev;
te->next_event = next_event;
te->handler = handler;
te->private_data = private_data;
te->additional_data = NULL;
/* keep the list ordered */
last_te = NULL;
for (cur_te = ev->timer_events; cur_te; cur_te = cur_te->next) {
/* if the new event comes before the current one break */
if (ev_timeval_compare(&te->next_event, &cur_te->next_event) < 0) {
break;
}
last_te = cur_te;
}
DLIST_ADD_AFTER(ev->timer_events, te, last_te);
talloc_set_destructor(te, common_event_timed_destructor);
return te;
}
/*
do a single event loop using the events defined in ev
return the delay untill the next timed event,
or zero if a timed event was triggered
*/
struct timeval common_event_loop_timer_delay(struct tevent_context *ev)
{
struct timeval current_time = ev_timeval_zero();
struct tevent_timer *te = ev->timer_events;
if (!te) {
/* have a default tick time of 30 seconds. This guarantees
that code that uses its own timeout checking will be
able to proceeed eventually */
return ev_timeval_set(30, 0);
}
/*
* work out the right timeout for the next timed event
*
* avoid the syscall to gettimeofday() if the timed event should
* be triggered directly
*
* if there's a delay till the next timed event, we're done
* with just returning the delay
*/
if (!ev_timeval_is_zero(&te->next_event)) {
struct timeval delay;
current_time = ev_timeval_current();
delay = ev_timeval_until(¤t_time, &te->next_event);
if (!ev_timeval_is_zero(&delay)) {
return delay;
}
}
/*
* ok, we have a timed event that we'll process ...
*/
/* deny the handler to free the event */
talloc_set_destructor(te, common_event_timed_deny_destructor);
/* We need to remove the timer from the list before calling the
* handler because in a semi-async inner event loop called from the
* handler we don't want to come across this event again -- vl */
DLIST_REMOVE(ev->timer_events, te);
/*
* If the timed event was registered for a zero current_time,
* then we pass a zero timeval here too! To avoid the
* overhead of gettimeofday() calls.
*
* otherwise we pass the current time
*/
te->handler(ev, te, current_time, te->private_data);
/* The destructor isn't necessary anymore, we've already removed the
* event from the list. */
talloc_set_destructor(te, NULL);
talloc_free(te);
return ev_timeval_zero();
}
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