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/* $OpenBSD: kqueue.c,v 1.5 2002/07/10 14:41:31 art Exp $ */
/*
* Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
* Copyright 2007-2012 Niels Provos and Nick Mathewson
*
* 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 "event2/event-config.h"
#define _GNU_SOURCE
#include <sys/types.h>
#ifdef _EVENT_HAVE_SYS_TIME_H
#include <sys/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>
#ifdef _EVENT_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(_EVENT_HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__)
#define PTR_TO_UDATA(x) ((intptr_t)(x))
#define INT_TO_UDATA(x) ((intptr_t)(x))
#else
#define PTR_TO_UDATA(x) (x)
#define INT_TO_UDATA(x) ((void*)(x))
#endif
#include "event-internal.h"
#include "log-internal.h"
#include "evmap-internal.h"
#include "event2/thread.h"
#include "evthread-internal.h"
#include "changelist-internal.h"
#define NEVENT 64
struct kqop {
struct kevent *changes;
int changes_size;
struct kevent *events;
int events_size;
int kq;
pid_t pid;
};
static void kqop_free(struct kqop *kqop);
static void *kq_init(struct event_base *);
static int kq_sig_add(struct event_base *, int, short, short, void *);
static int kq_sig_del(struct event_base *, int, short, short, void *);
static int kq_dispatch(struct event_base *, struct timeval *);
static void kq_dealloc(struct event_base *);
const struct eventop kqops = {
"kqueue",
kq_init,
event_changelist_add,
event_changelist_del,
kq_dispatch,
kq_dealloc,
1 /* need reinit */,
EV_FEATURE_ET|EV_FEATURE_O1|EV_FEATURE_FDS,
EVENT_CHANGELIST_FDINFO_SIZE
};
static const struct eventop kqsigops = {
"kqueue_signal",
NULL,
kq_sig_add,
kq_sig_del,
NULL,
NULL,
1 /* need reinit */,
0,
0
};
static void *
kq_init(struct event_base *base)
{
int kq = -1;
struct kqop *kqueueop = NULL;
if (!(kqueueop = mm_calloc(1, sizeof(struct kqop))))
return (NULL);
/* Initialize the kernel queue */
if ((kq = kqueue()) == -1) {
event_warn("kqueue");
goto err;
}
kqueueop->kq = kq;
kqueueop->pid = getpid();
/* Initialize fields */
kqueueop->changes = mm_calloc(NEVENT, sizeof(struct kevent));
if (kqueueop->changes == NULL)
goto err;
kqueueop->events = mm_calloc(NEVENT, sizeof(struct kevent));
if (kqueueop->events == NULL)
goto err;
kqueueop->events_size = kqueueop->changes_size = NEVENT;
/* Check for Mac OS X kqueue bug. */
memset(&kqueueop->changes[0], 0, sizeof kqueueop->changes[0]);
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 ||
(int)kqueueop->events[0].ident != -1 ||
kqueueop->events[0].flags != EV_ERROR) {
event_warn("%s: detected broken kqueue; not using.", __func__);
goto err;
}
base->evsigsel = &kqsigops;
return (kqueueop);
err:
if (kqueueop)
kqop_free(kqueueop);
return (NULL);
}
static void
kq_sighandler(int sig)
{
/* Do nothing here */
}
#define ADD_UDATA 0x30303
static void
kq_setup_kevent(struct kevent *out, evutil_socket_t fd, int filter, short change)
{
memset(out, 0, sizeof(struct kevent));
out->ident = fd;
out->filter = filter;
if (change & EV_CHANGE_ADD) {
out->flags = EV_ADD;
/* We set a magic number here so that we can tell 'add'
* errors from 'del' errors. */
out->udata = INT_TO_UDATA(ADD_UDATA);
if (change & EV_ET)
out->flags |= EV_CLEAR;
#ifdef NOTE_EOF
/* Make it behave like select() and poll() */
if (filter == EVFILT_READ)
out->fflags = NOTE_EOF;
#endif
} else {
EVUTIL_ASSERT(change & EV_CHANGE_DEL);
out->flags = EV_DELETE;
}
}
static int
kq_build_changes_list(const struct event_changelist *changelist,
struct kqop *kqop)
{
int i;
int n_changes = 0;
for (i = 0; i < changelist->n_changes; ++i) {
struct event_change *in_ch = &changelist->changes[i];
struct kevent *out_ch;
if (n_changes >= kqop->changes_size - 1) {
int newsize = kqop->changes_size * 2;
struct kevent *newchanges;
newchanges = mm_realloc(kqop->changes,
newsize * sizeof(struct kevent));
if (newchanges == NULL) {
event_warn("%s: realloc", __func__);
return (-1);
}
kqop->changes = newchanges;
kqop->changes_size = newsize;
}
if (in_ch->read_change) {
out_ch = &kqop->changes[n_changes++];
kq_setup_kevent(out_ch, in_ch->fd, EVFILT_READ,
in_ch->read_change);
}
if (in_ch->write_change) {
out_ch = &kqop->changes[n_changes++];
kq_setup_kevent(out_ch, in_ch->fd, EVFILT_WRITE,
in_ch->write_change);
}
}
return n_changes;
}
static int
kq_grow_events(struct kqop *kqop, size_t new_size)
{
struct kevent *newresult;
newresult = mm_realloc(kqop->events,
new_size * sizeof(struct kevent));
if (newresult) {
kqop->events = newresult;
kqop->events_size = new_size;
return 0;
} else {
return -1;
}
}
static int
kq_dispatch(struct event_base *base, struct timeval *tv)
{
struct kqop *kqop = base->evbase;
struct kevent *events = kqop->events;
struct kevent *changes;
struct timespec ts, *ts_p = NULL;
int i, n_changes, res;
if (tv != NULL) {
TIMEVAL_TO_TIMESPEC(tv, &ts);
ts_p = &ts;
}
/* Build "changes" from "base->changes" */
EVUTIL_ASSERT(kqop->changes);
n_changes = kq_build_changes_list(&base->changelist, kqop);
if (n_changes < 0)
return -1;
event_changelist_remove_all(&base->changelist, base);
/* steal the changes array in case some broken code tries to call
* dispatch twice at once. */
changes = kqop->changes;
kqop->changes = NULL;
/* Make sure that 'events' is at least as long as the list of changes:
* otherwise errors in the changes can get reported as a -1 return
* value from kevent() rather than as EV_ERROR events in the events
* array.
*
* (We could instead handle -1 return values from kevent() by
* retrying with a smaller changes array or a larger events array,
* but this approach seems less risky for now.)
*/
if (kqop->events_size < n_changes) {
int new_size = kqop->events_size;
do {
new_size *= 2;
} while (new_size < n_changes);
kq_grow_events(kqop, new_size);
events = kqop->events;
}
EVBASE_RELEASE_LOCK(base, th_base_lock);
res = kevent(kqop->kq, changes, n_changes,
events, kqop->events_size, ts_p);
EVBASE_ACQUIRE_LOCK(base, th_base_lock);
EVUTIL_ASSERT(kqop->changes == NULL);
kqop->changes = changes;
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. */
case EBADF:
/* XXXX On NetBSD, we can also get EBADF if we
* try to add the write side of a pipe, but
* the read side has already been closed.
* Other BSDs call this situation 'EPIPE'. It
* would be good if we had a way to report
* this situation. */
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) {
evmap_signal_active(base, events[i].ident, 1);
} else {
evmap_io_active(base, events[i].ident, which | EV_ET);
}
}
if (res == kqop->events_size) {
/* We used all the events space that we have. Maybe we should
make it bigger. */
kq_grow_events(kqop, kqop->events_size * 2);
}
return (0);
}
static void
kqop_free(struct kqop *kqop)
{
if (kqop->changes)
mm_free(kqop->changes);
if (kqop->events)
mm_free(kqop->events);
if (kqop->kq >= 0 && kqop->pid == getpid())
close(kqop->kq);
memset(kqop, 0, sizeof(struct kqop));
mm_free(kqop);
}
static void
kq_dealloc(struct event_base *base)
{
struct kqop *kqop = base->evbase;
evsig_dealloc(base);
kqop_free(kqop);
}
/* signal handling */
static int
kq_sig_add(struct event_base *base, int nsignal, short old, short events, void *p)
{
struct kqop *kqop = base->evbase;
struct kevent kev;
struct timespec timeout = { 0, 0 };
(void)p;
EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
memset(&kev, 0, sizeof(kev));
kev.ident = nsignal;
kev.filter = EVFILT_SIGNAL;
kev.flags = EV_ADD;
/* 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);
/* XXXX The manpage suggest we could use SIG_IGN instead of a
* do-nothing handler */
if (_evsig_set_handler(base, nsignal, kq_sighandler) == -1)
return (-1);
return (0);
}
static int
kq_sig_del(struct event_base *base, int nsignal, short old, short events, void *p)
{
struct kqop *kqop = base->evbase;
struct kevent kev;
struct timespec timeout = { 0, 0 };
(void)p;
EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
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 (_evsig_restore_handler(base, nsignal) == -1)
return (-1);
return (0);
}
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