/* $OpenBSD: kqueue.c,v 1.5 2002/07/10 14:41:31 art 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. 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
#define _GNU_SOURCE 1
#include <sys/types.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <sys/_libevent_time.h>
#endif
#include <sys/queue.h>
#include <sys/event.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif
/* Some platforms apparently define the udata field of struct kevent as
* intptr_t, whereas others define it as void*. There doesn't seem to be an
* easy way to tell them apart via autoconf, so we need to use OS macros. */
#if defined(HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__)
#define PTR_TO_UDATA(x) ((intptr_t)(x))
#else
#define PTR_TO_UDATA(x) (x)
#endif
#include "event.h"
#include "event-internal.h"
#include "log.h"
#define EVLIST_X_KQINKERNEL 0x1000
#define NEVENT 64
struct kqop {
struct kevent *changes;
int nchanges;
struct kevent *events;
struct event_list evsigevents[NSIG];
int nevents;
int kq;
pid_t pid;
};
static void *kq_init (struct event_base *);
static int kq_add (void *, struct event *);
static int kq_del (void *, struct event *);
static int kq_dispatch (struct event_base *, void *, struct timeval *);
static int kq_insert (struct kqop *, struct kevent *);
static void kq_dealloc (struct event_base *, void *);
const struct eventop kqops = {
"kqueue",
kq_init,
kq_add,
kq_del,
kq_dispatch,
kq_dealloc,
1 /* need reinit */
};
static void *
kq_init(struct event_base *base)
{
int i, kq;
struct kqop *kqueueop;
/* Disable kqueue when this environment variable is set */
if (evutil_getenv("EVENT_NOKQUEUE"))
return (NULL);
if (!(kqueueop = calloc(1, sizeof(struct kqop))))
return (NULL);
/* Initalize the kernel queue */
if ((kq = kqueue()) == -1) {
event_warn("kqueue");
free (kqueueop);
return (NULL);
}
kqueueop->kq = kq;
kqueueop->pid = getpid();
/* Initalize fields */
kqueueop->changes = malloc(NEVENT * sizeof(struct kevent));
if (kqueueop->changes == NULL) {
free (kqueueop);
return (NULL);
}
kqueueop->events = malloc(NEVENT * sizeof(struct kevent));
if (kqueueop->events == NULL) {
free (kqueueop->changes);
free (kqueueop);
return (NULL);
}
kqueueop->nevents = NEVENT;
/* we need to keep track of multiple events per signal */
for (i = 0; i < NSIG; ++i) {
TAILQ_INIT(&kqueueop->evsigevents[i]);
}
/* Check for Mac OS X kqueue bug. */
kqueueop->changes[0].ident = -1;
kqueueop->changes[0].filter = EVFILT_READ;
kqueueop->changes[0].flags = EV_ADD;
/*
* If kqueue works, then kevent will succeed, and it will
* stick an error in events[0]. If kqueue is broken, then
* kevent will fail.
*/
if (kevent(kq,
kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 ||
kqueueop->events[0].ident != -1 ||
kqueueop->events[0].flags != EV_ERROR) {
event_warn("%s: detected broken kqueue; not using.", __func__);
free(kqueueop->changes);
free(kqueueop->events);
free(kqueueop);
close(kq);
return (NULL);
}
return (kqueueop);
}
static int
kq_insert(struct kqop *kqop, struct kevent *kev)
{
int nevents = kqop->nevents;
if (kqop->nchanges == nevents) {
struct kevent *newchange;
struct kevent *newresult;
nevents *= 2;
newchange = realloc(kqop->changes,
nevents * sizeof(struct kevent));
if (newchange == NULL) {
event_warn("%s: malloc", __func__);
return (-1);
}
kqop->changes = newchange;
newresult = realloc(kqop->events,
nevents * sizeof(struct kevent));
/*
* If we fail, we don't have to worry about freeing,
* the next realloc will pick it up.
*/
if (newresult == NULL) {
event_warn("%s: malloc", __func__);
return (-1);
}
kqop->events = newresult;
kqop->nevents = nevents;
}
memcpy(&kqop->changes[kqop->nchanges++], kev, sizeof(struct kevent));
event_debug(("%s: fd %d %s%s",
__func__, (int)kev->ident,
kev->filter == EVFILT_READ ? "EVFILT_READ" : "EVFILT_WRITE",
kev->flags == EV_DELETE ? " (del)" : ""));
return (0);
}
static void
kq_sighandler(int sig)
{
/* Do nothing here */
}
static int
kq_dispatch(struct event_base *base, void *arg, struct timeval *tv)
{
struct kqop *kqop = arg;
struct kevent *changes = kqop->changes;
struct kevent *events = kqop->events;
struct event *ev;
struct timespec ts, *ts_p = NULL;
int i, res;
if (tv != NULL) {
TIMEVAL_TO_TIMESPEC(tv, &ts);
ts_p = &ts;
}
res = kevent(kqop->kq, changes, kqop->nchanges,
events, kqop->nevents, ts_p);
kqop->nchanges = 0;
if (res == -1) {
if (errno != EINTR) {
event_warn("kevent");
return (-1);
}
return (0);
}
event_debug(("%s: kevent reports %d", __func__, res));
for (i = 0; i < res; i++) {
int which = 0;
if (events[i].flags & EV_ERROR) {
/*
* Error messages that can happen, when a delete fails.
* EBADF happens when the file discriptor has been
* closed,
* ENOENT when the file discriptor was closed and
* then reopened.
* EINVAL for some reasons not understood; EINVAL
* should not be returned ever; but FreeBSD does :-\
* An error is also indicated when a callback deletes
* an event we are still processing. In that case
* the data field is set to ENOENT.
*/
if (events[i].data == EBADF ||
events[i].data == EINVAL ||
events[i].data == ENOENT)
continue;
errno = events[i].data;
return (-1);
}
if (events[i].filter == EVFILT_READ) {
which |= EV_READ;
} else if (events[i].filter == EVFILT_WRITE) {
which |= EV_WRITE;
} else if (events[i].filter == EVFILT_SIGNAL) {
which |= EV_SIGNAL;
}
if (!which)
continue;
if (events[i].filter == EVFILT_SIGNAL) {
struct event_list *head =
(struct event_list *)events[i].udata;
TAILQ_FOREACH(ev, head, ev_signal_next) {
event_active(ev, which, events[i].data);
}
} else {
ev = (struct event *)events[i].udata;
if (!(ev->ev_events & EV_PERSIST))
ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
event_active(ev, which, 1);
}
}
return (0);
}
static int
kq_add(void *arg, struct event *ev)
{
struct kqop *kqop = arg;
struct kevent kev;
if (ev->ev_events & EV_SIGNAL) {
int nsignal = EVENT_SIGNAL(ev);
assert(nsignal >= 0 && nsignal < NSIG);
if (TAILQ_EMPTY(&kqop->evsigevents[nsignal])) {
struct timespec timeout = { 0, 0 };
memset(&kev, 0, sizeof(kev));
kev.ident = nsignal;
kev.filter = EVFILT_SIGNAL;
kev.flags = EV_ADD;
kev.udata = PTR_TO_UDATA(&kqop->evsigevents[nsignal]);
/* Be ready for the signal if it is sent any
* time between now and the next call to
* kq_dispatch. */
if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
return (-1);
if (_evsignal_set_handler(ev->ev_base, nsignal,
kq_sighandler) == -1)
return (-1);
}
TAILQ_INSERT_TAIL(&kqop->evsigevents[nsignal], ev,
ev_signal_next);
ev->ev_flags |= EVLIST_X_KQINKERNEL;
return (0);
}
if (ev->ev_events & EV_READ) {
memset(&kev, 0, sizeof(kev));
kev.ident = ev->ev_fd;
kev.filter = EVFILT_READ;
#ifdef NOTE_EOF
/* Make it behave like select() and poll() */
kev.fflags = NOTE_EOF;
#endif
kev.flags = EV_ADD;
if (!(ev->ev_events & EV_PERSIST))
kev.flags |= EV_ONESHOT;
kev.udata = PTR_TO_UDATA(ev);
if (kq_insert(kqop, &kev) == -1)
return (-1);
ev->ev_flags |= EVLIST_X_KQINKERNEL;
}
if (ev->ev_events & EV_WRITE) {
memset(&kev, 0, sizeof(kev));
kev.ident = ev->ev_fd;
kev.filter = EVFILT_WRITE;
kev.flags = EV_ADD;
if (!(ev->ev_events & EV_PERSIST))
kev.flags |= EV_ONESHOT;
kev.udata = PTR_TO_UDATA(ev);
if (kq_insert(kqop, &kev) == -1)
return (-1);
ev->ev_flags |= EVLIST_X_KQINKERNEL;
}
return (0);
}
static int
kq_del(void *arg, struct event *ev)
{
struct kqop *kqop = arg;
struct kevent kev;
if (!(ev->ev_flags & EVLIST_X_KQINKERNEL))
return (0);
if (ev->ev_events & EV_SIGNAL) {
int nsignal = EVENT_SIGNAL(ev);
struct timespec timeout = { 0, 0 };
assert(nsignal >= 0 && nsignal < NSIG);
TAILQ_REMOVE(&kqop->evsigevents[nsignal], ev, ev_signal_next);
if (TAILQ_EMPTY(&kqop->evsigevents[nsignal])) {
memset(&kev, 0, sizeof(kev));
kev.ident = nsignal;
kev.filter = EVFILT_SIGNAL;
kev.flags = EV_DELETE;
/* Because we insert signal events
* immediately, we need to delete them
* immediately, too */
if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
return (-1);
if (_evsignal_restore_handler(ev->ev_base,
nsignal) == -1)
return (-1);
}
ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
return (0);
}
if (ev->ev_events & EV_READ) {
memset(&kev, 0, sizeof(kev));
kev.ident = ev->ev_fd;
kev.filter = EVFILT_READ;
kev.flags = EV_DELETE;
if (kq_insert(kqop, &kev) == -1)
return (-1);
ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
}
if (ev->ev_events & EV_WRITE) {
memset(&kev, 0, sizeof(kev));
kev.ident = ev->ev_fd;
kev.filter = EVFILT_WRITE;
kev.flags = EV_DELETE;
if (kq_insert(kqop, &kev) == -1)
return (-1);
ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
}
return (0);
}
static void
kq_dealloc(struct event_base *base, void *arg)
{
struct kqop *kqop = arg;
if (kqop->changes)
free(kqop->changes);
if (kqop->events)
free(kqop->events);
if (kqop->kq >= 0 && kqop->pid == getpid())
close(kqop->kq);
memset(kqop, 0, sizeof(struct kqop));
free(kqop);
}