src/lib/libevent/kqueue.c

452 lines
11 KiB
C

/* $OpenBSD: kqueue.c,v 1.43 2024/03/23 22:51:49 yasuoka 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.
*/
#include <sys/types.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "event.h"
#include "event-internal.h"
#include "log.h"
#include "evsignal.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 (!issetugid() && getenv("EVENT_NOKQUEUE"))
return (NULL);
if (!(kqueueop = calloc(1, sizeof(struct kqop))))
return (NULL);
/* Initialize the kernel queue */
if ((kq = kqueue()) == -1) {
event_warn("kqueue");
free (kqueueop);
return (NULL);
}
kqueueop->kq = kq;
kqueueop->pid = getpid();
/* Initialize fields */
kqueueop->changes = calloc(NEVENT, sizeof(struct kevent));
if (kqueueop->changes == NULL) {
free (kqueueop);
return (NULL);
}
kqueueop->events = calloc(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]);
}
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;
if (nevents > INT_MAX / 2) {
event_warnx("%s: integer overflow", __func__);
return (-1);
}
nevents *= 2;
newchange = recallocarray(kqop->changes,
kqop->nevents, nevents, sizeof(struct kevent));
if (newchange == NULL) {
event_warn("%s: recallocarray", __func__);
return (-1);
}
kqop->changes = newchange;
newresult = recallocarray(kqop->events,
kqop->nevents, 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: recallocarray", __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, kqop->nchanges ? changes : NULL, 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) {
switch (events[i].data) {
/* Can occur on delete if we are not currently
* watching any events on this fd. That can
* happen when the fd was closed and another
* file was opened with that fd. */
case ENOENT:
/* Can occur for reasons not fully understood
* on FreeBSD. */
case EINVAL:
continue;
/* Can occur on a delete if the fd is closed. Can
* occur on an add if the fd was one side of a pipe,
* and the other side was closed. */
case EBADF:
continue;
/* These two can occur on an add if the fd was one side
* of a pipe, and the other side was closed. */
case EPERM:
case EPIPE:
/* Report read events, if we're listening for
* them, so that the user can learn about any
* add errors. (If the operation was a
* delete, then udata should be cleared.) */
if (events[i].udata) {
/* The operation was an add:
* report the error as a read. */
which |= EV_READ;
break;
} else {
/* The operation was a del:
* report nothing. */
continue;
}
/* Other errors shouldn't occur. */
default:
errno = events[i].data;
return (-1);
}
} else 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 = &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;
/* Make it behave like select() and poll() */
kev.fflags = NOTE_EOF;
kev.flags = EV_ADD;
if (!(ev->ev_events & EV_PERSIST))
kev.flags |= EV_ONESHOT;
kev.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 = 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)
{
int i, j;
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);
}
for (i = j = 0; i < kqop->nchanges; i++) {
if (kqop->changes[i].udata == ev &&
(kqop->changes[i].flags & EV_ADD) != 0)
continue; /* delete this */
if (i != j)
memcpy(&kqop->changes[j], &kqop->changes[i],
sizeof(struct kevent));
j++;
}
if (kqop->nchanges != j) {
kqop->nchanges = j;
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;
evsignal_dealloc(base);
free(kqop->changes);
free(kqop->events);
if (kqop->kq >= 0 && kqop->pid == getpid())
close(kqop->kq);
memset(kqop, 0, sizeof(struct kqop));
free(kqop);
}