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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);

 }

 #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);

 	/* Backported from

 	 * https://github.com/nmathewson/Libevent/commit/148458e0a1fd25e167aa2ef229d1c9a70b27c3e9 */

 	/* We can set the handler for most signals to SIG_IGN and

 	 * still have them reported to us in the queue.  However,

 	 * if the handler for SIGCHLD is SIG_IGN, the system reaps

 	 * zombie processes for us, and we don't get any notification.

 	 * This appears to be the only signal with this quirk. */

 	if (_evsig_set_handler(base, nsignal,

 	                       nsignal == SIGCHLD ? SIG_DFL : SIG_IGN) == -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);

 }