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NetBSD/lib/libevent/event.c

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/* $NetBSD: event.c,v 1.3 2003/06/13 04:11:31 itojun Exp $ */
/* $OpenBSD: event.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
/*
* Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Niels Provos.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/tree.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <sys/_time.h>
#endif
#include <sys/queue.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <err.h>
#include <assert.h>
#ifdef USE_LOG
#include "log.h"
#else
#define LOG_DBG(x)
#define log_error(x) perror(x)
#endif
#include "event.h"
#ifdef HAVE_SELECT
extern struct eventop selectops;
#endif
#ifdef HAVE_POLL
extern struct eventop pollops;
#endif
#ifdef HAVE_EPOLL
extern struct eventop epollops;
#endif
#ifdef HAVE_WORKING_KQUEUE
extern struct eventop kqops;
#endif
/* In order of preference */
struct eventop *eventops[] = {
#ifdef HAVE_WORKING_KQUEUE
&kqops,
#endif
#ifdef HAVE_EPOLL
&epollops,
#endif
#ifdef HAVE_POLL
&pollops,
#endif
#ifdef HAVE_SELECT
&selectops,
#endif
NULL
};
struct eventop *evsel;
void *evbase;
/* Handle signals */
int (*event_sigcb)(void); /* Signal callback when gotsig is set */
int event_gotsig; /* Set in signal handler */
/* Prototypes */
void event_queue_insert(struct event *, int);
void event_queue_remove(struct event *, int);
int event_haveevents(void);
void event_process_active(void);
void timeout_insert(struct event *);
static RB_HEAD(event_tree, event) timetree;
static struct event_list activequeue;
struct event_list signalqueue;
struct event_list eventqueue;
static struct timeval event_tv;
static int
compare(struct event *a, struct event *b)
{
if (timercmp(&a->ev_timeout, &b->ev_timeout, <))
return (-1);
else if (timercmp(&a->ev_timeout, &b->ev_timeout, >))
return (1);
return (0);
}
RB_PROTOTYPE(event_tree, event, ev_timeout_node, compare);
RB_GENERATE(event_tree, event, ev_timeout_node, compare);
void
event_init(void)
{
int i;
event_sigcb = NULL;
event_gotsig = 0;
gettimeofday(&event_tv, NULL);
RB_INIT(&timetree);
TAILQ_INIT(&eventqueue);
TAILQ_INIT(&activequeue);
TAILQ_INIT(&signalqueue);
evbase = NULL;
for (i = 0; eventops[i] && !evbase; i++) {
evsel = eventops[i];
evbase = evsel->init();
}
if (evbase == NULL)
errx(1, "%s: no event mechanism available", __func__);
if (!issetugid() && getenv("EVENT_SHOW_METHOD"))
fprintf(stderr, "libevent using: %s\n", evsel->name);
#if defined(USE_LOG) && defined(USE_DEBUG)
log_to(stderr);
log_debug_cmd(LOG_MISC, 80);
#endif
}
int
event_haveevents(void)
{
return (RB_ROOT(&timetree) || TAILQ_FIRST(&eventqueue) ||
TAILQ_FIRST(&signalqueue) || TAILQ_FIRST(&activequeue));
}
void
event_process_active(void)
{
struct event *ev;
short ncalls;
for (ev = TAILQ_FIRST(&activequeue); ev;
ev = TAILQ_FIRST(&activequeue)) {
event_queue_remove(ev, EVLIST_ACTIVE);
/* Allows deletes to work */
ncalls = ev->ev_ncalls;
ev->ev_pncalls = &ncalls;
while (ncalls) {
ncalls--;
ev->ev_ncalls = ncalls;
(*ev->ev_callback)(ev->ev_fd, ev->ev_res, ev->ev_arg);
}
}
}
int
event_dispatch(void)
{
return (event_loop(0));
}
int
event_loop(int flags)
{
struct timeval tv;
int res, done;
/* Calculate the initial events that we are waiting for */
if (evsel->recalc(evbase, 0) == -1)
return (-1);
done = 0;
while (!done) {
while (event_gotsig) {
event_gotsig = 0;
if (event_sigcb) {
res = (*event_sigcb)();
if (res == -1) {
errno = EINTR;
return (-1);
}
}
}
/* Check if time is running backwards */
gettimeofday(&tv, NULL);
if (timercmp(&tv, &event_tv, <)) {
struct timeval off;
LOG_DBG((LOG_MIST, 10,
"%s: time is running backwards, corrected",
__func__));
timersub(&event_tv, &tv, &off);
timeout_correct(&off);
}
event_tv = tv;
if (!(flags & EVLOOP_NONBLOCK))
timeout_next(&tv);
else
timerclear(&tv);
/* If we have no events, we just exit */
if (!event_haveevents())
return (1);
res = evsel->dispatch(evbase, &tv);
if (res == -1)
return (-1);
timeout_process();
if (TAILQ_FIRST(&activequeue)) {
event_process_active();
if (flags & EVLOOP_ONCE)
done = 1;
} else if (flags & EVLOOP_NONBLOCK)
done = 1;
if (evsel->recalc(evbase, 0) == -1)
return (-1);
}
return (0);
}
void
event_set(struct event *ev, int fd, short events,
void (*callback)(int, short, void *), void *arg)
{
ev->ev_callback = callback;
ev->ev_arg = arg;
ev->ev_fd = fd;
ev->ev_events = events;
ev->ev_flags = EVLIST_INIT;
ev->ev_ncalls = 0;
ev->ev_pncalls = NULL;
}
/*
* Checks if a specific event is pending or scheduled.
*/
int
event_pending(struct event *ev, short event, struct timeval *tv)
{
int flags = 0;
if (ev->ev_flags & EVLIST_INSERTED)
flags |= (ev->ev_events & (EV_READ|EV_WRITE));
if (ev->ev_flags & EVLIST_ACTIVE)
flags |= ev->ev_res;
if (ev->ev_flags & EVLIST_TIMEOUT)
flags |= EV_TIMEOUT;
event &= (EV_TIMEOUT|EV_READ|EV_WRITE);
/* See if there is a timeout that we should report */
if (tv != NULL && (flags & event & EV_TIMEOUT))
*tv = ev->ev_timeout;
return (flags & event);
}
int
event_add(struct event *ev, struct timeval *tv)
{
LOG_DBG((LOG_MISC, 55,
"event_add: event: %p, %s%s%scall %p",
ev,
ev->ev_events & EV_READ ? "EV_READ " : " ",
ev->ev_events & EV_WRITE ? "EV_WRITE " : " ",
tv ? "EV_TIMEOUT " : " ",
ev->ev_callback));
assert(!(ev->ev_flags & ~EVLIST_ALL));
if (tv != NULL) {
struct timeval now;
if (ev->ev_flags & EVLIST_TIMEOUT)
event_queue_remove(ev, EVLIST_TIMEOUT);
/* Check if it is active due to a timeout. Rescheduling
* this timeout before the callback can be executed
* removes it from the active list. */
if ((ev->ev_flags & EVLIST_ACTIVE) &&
(ev->ev_res & EV_TIMEOUT)) {
/* See if we are just active executing this
* event in a loop
*/
if (ev->ev_ncalls && ev->ev_pncalls) {
/* Abort loop */
*ev->ev_pncalls = 0;
}
event_queue_remove(ev, EVLIST_ACTIVE);
}
gettimeofday(&now, NULL);
timeradd(&now, tv, &ev->ev_timeout);
LOG_DBG((LOG_MISC, 55,
"event_add: timeout in %d seconds, call %p",
tv->tv_sec, ev->ev_callback));
event_queue_insert(ev, EVLIST_TIMEOUT);
}
if ((ev->ev_events & (EV_READ|EV_WRITE)) &&
!(ev->ev_flags & (EVLIST_INSERTED|EVLIST_ACTIVE))) {
event_queue_insert(ev, EVLIST_INSERTED);
return (evsel->add(evbase, ev));
} else if ((ev->ev_events & EV_SIGNAL) &&
!(ev->ev_flags & EVLIST_SIGNAL)) {
event_queue_insert(ev, EVLIST_SIGNAL);
return (evsel->add(evbase, ev));
}
return (0);
}
int
event_del(struct event *ev)
{
LOG_DBG((LOG_MISC, 80, "event_del: %p, callback %p",
ev, ev->ev_callback));
assert(!(ev->ev_flags & ~EVLIST_ALL));
/* See if we are just active executing this event in a loop */
if (ev->ev_ncalls && ev->ev_pncalls) {
/* Abort loop */
*ev->ev_pncalls = 0;
}
if (ev->ev_flags & EVLIST_TIMEOUT)
event_queue_remove(ev, EVLIST_TIMEOUT);
if (ev->ev_flags & EVLIST_ACTIVE)
event_queue_remove(ev, EVLIST_ACTIVE);
if (ev->ev_flags & EVLIST_INSERTED) {
event_queue_remove(ev, EVLIST_INSERTED);
return (evsel->del(evbase, ev));
} else if (ev->ev_flags & EVLIST_SIGNAL) {
event_queue_remove(ev, EVLIST_SIGNAL);
return (evsel->del(evbase, ev));
}
return (0);
}
void
event_active(struct event *ev, int res, short ncalls)
{
/* We get different kinds of events, add them together */
if (ev->ev_flags & EVLIST_ACTIVE) {
ev->ev_res |= res;
return;
}
ev->ev_res = res;
ev->ev_ncalls = ncalls;
ev->ev_pncalls = NULL;
event_queue_insert(ev, EVLIST_ACTIVE);
}
int
timeout_next(struct timeval *tv)
{
struct timeval dflt = TIMEOUT_DEFAULT;
struct timeval now;
struct event *ev;
if ((ev = RB_MIN(event_tree, &timetree)) == NULL) {
*tv = dflt;
return (0);
}
if (gettimeofday(&now, NULL) == -1)
return (-1);
if (timercmp(&ev->ev_timeout, &now, <=)) {
timerclear(tv);
return (0);
}
timersub(&ev->ev_timeout, &now, tv);
LOG_DBG((LOG_MISC, 60, "timeout_next: in %d seconds", tv->tv_sec));
return (0);
}
void
timeout_correct(struct timeval *off)
{
struct event *ev;
/* We can modify the key element of the node without destroying
* the key, beause we apply it to all in the right order.
*/
RB_FOREACH(ev, event_tree, &timetree)
timersub(&ev->ev_timeout, off, &ev->ev_timeout);
}
void
timeout_process(void)
{
struct timeval now;
struct event *ev, *next;
gettimeofday(&now, NULL);
for (ev = RB_MIN(event_tree, &timetree); ev; ev = next) {
if (timercmp(&ev->ev_timeout, &now, >))
break;
next = RB_NEXT(event_tree, &timetree, ev);
event_queue_remove(ev, EVLIST_TIMEOUT);
/* delete this event from the I/O queues */
event_del(ev);
LOG_DBG((LOG_MISC, 60, "timeout_process: call %p",
ev->ev_callback));
event_active(ev, EV_TIMEOUT, 1);
}
}
void
timeout_insert(struct event *ev)
{
struct event *tmp;
tmp = RB_FIND(event_tree, &timetree, ev);
if (tmp != NULL) {
struct timeval tv;
struct timeval add = {0,1};
/* Find unique time */
tv = ev->ev_timeout;
do {
timeradd(&tv, &add, &tv);
tmp = RB_NEXT(event_tree, &timetree, tmp);
} while (tmp != NULL && timercmp(&tmp->ev_timeout, &tv, ==));
ev->ev_timeout = tv;
}
tmp = RB_INSERT(event_tree, &timetree, ev);
assert(tmp == NULL);
}
void
event_queue_remove(struct event *ev, int queue)
{
if (!(ev->ev_flags & queue))
errx(1, "%s: %p(fd %d) not on queue %x", __func__,
ev, ev->ev_fd, queue);
ev->ev_flags &= ~queue;
switch (queue) {
case EVLIST_ACTIVE:
TAILQ_REMOVE(&activequeue, ev, ev_active_next);
break;
case EVLIST_SIGNAL:
TAILQ_REMOVE(&signalqueue, ev, ev_signal_next);
break;
case EVLIST_TIMEOUT:
RB_REMOVE(event_tree, &timetree, ev);
break;
case EVLIST_INSERTED:
TAILQ_REMOVE(&eventqueue, ev, ev_next);
break;
default:
errx(1, "%s: unknown queue %x", __func__, queue);
}
}
void
event_queue_insert(struct event *ev, int queue)
{
if (ev->ev_flags & queue)
errx(1, "%s: %p(fd %d) already on queue %x", __func__,
ev, ev->ev_fd, queue);
ev->ev_flags |= queue;
switch (queue) {
case EVLIST_ACTIVE:
TAILQ_INSERT_TAIL(&activequeue, ev, ev_active_next);
break;
case EVLIST_SIGNAL:
TAILQ_INSERT_TAIL(&signalqueue, ev, ev_signal_next);
break;
case EVLIST_TIMEOUT:
timeout_insert(ev);
break;
case EVLIST_INSERTED:
TAILQ_INSERT_TAIL(&eventqueue, ev, ev_next);
break;
default:
errx(1, "%s: unknown queue %x", __func__, queue);
}
}
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