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 /*

  * Submitted by David Pacheco (dp.spambait@gmail.com)

  *

  * Copyright 2006-2007 Niels Provos

  * 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 SUN MICROSYSTEMS, INC. ``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 SUN MICROSYSTEMS, INC. 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.

  */

 /*

  * Copyright (c) 2007 Sun Microsystems. All rights reserved.

  * Use is subject to license terms.

  */

 /*

  * evport.c: event backend using Solaris 10 event ports. See port_create(3C).

  * This implementation is loosely modeled after the one used for select(2) (in

  * select.c).

  *

  * The outstanding events are tracked in a data structure called evport_data.

  * Each entry in the ed_fds array corresponds to a file descriptor, and contains

  * pointers to the read and write events that correspond to that fd. (That is,

  * when the file is readable, the "read" event should handle it, etc.)

  *

  * evport_add and evport_del update this data structure. evport_dispatch uses it

  * to determine where to callback when an event occurs (which it gets from

  * port_getn).

  *

  * Helper functions are used: grow() grows the file descriptor array as

  * necessary when large fd's come in. reassociate() takes care of maintaining

  * the proper file-descriptor/event-port associations.

  *

  * As in the select(2) implementation, signals are handled by evsignal.

  */

 #include "event2/event-config.h"

 #include <sys/time.h>

 #include <sys/queue.h>

 #include <errno.h>

 #include <poll.h>

 #include <port.h>

 #include <signal.h>

 #include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

 #include <time.h>

 #include <unistd.h>

 #include "event2/thread.h"

 #include "evthread-internal.h"

 #include "event-internal.h"

 #include "log-internal.h"

 #include "evsignal-internal.h"

 #include "evmap-internal.h"

 /*

  * Default value for ed_nevents, which is the maximum file descriptor number we

  * can handle. If an event comes in for a file descriptor F > nevents, we will

  * grow the array of file descriptors, doubling its size.

  */

 #define DEFAULT_NFDS	16

 /*

  * EVENTS_PER_GETN is the maximum number of events to retrieve from port_getn on

  * any particular call. You can speed things up by increasing this, but it will

  * (obviously) require more memory.

  */

 #define EVENTS_PER_GETN 8

 /*

  * Per-file-descriptor information about what events we're subscribed to. These

  * fields are NULL if no event is subscribed to either of them.

  */

 struct fd_info {

 	short fdi_what;		/* combinations of EV_READ and EV_WRITE */

 };

 #define FDI_HAS_READ(fdi)  ((fdi)->fdi_what & EV_READ)

 #define FDI_HAS_WRITE(fdi) ((fdi)->fdi_what & EV_WRITE)

 #define FDI_HAS_EVENTS(fdi) (FDI_HAS_READ(fdi) || FDI_HAS_WRITE(fdi))

 #define FDI_TO_SYSEVENTS(fdi) (FDI_HAS_READ(fdi) ? POLLIN : 0) | \

     (FDI_HAS_WRITE(fdi) ? POLLOUT : 0)

 struct evport_data {

 	int		ed_port;	/* event port for system events  */

 	int		ed_nevents;	/* number of allocated fdi's	 */

 	struct fd_info *ed_fds;		/* allocated fdi table		 */

 	/* fdi's that we need to reassoc */

 	int ed_pending[EVENTS_PER_GETN]; /* fd's with pending events */

 };

 static void*	evport_init(struct event_base *);

 static int evport_add(struct event_base *, int fd, short old, short events, void *);

 static int evport_del(struct event_base *, int fd, short old, short events, void *);

 static int	evport_dispatch(struct event_base *, struct timeval *);

 static void	evport_dealloc(struct event_base *);

 const struct eventop evportops = {

 	"evport",

 	evport_init,

 	evport_add,

 	evport_del,

 	evport_dispatch,

 	evport_dealloc,

 	1, /* need reinit */

 	0, /* features */

 	0, /* fdinfo length */

 };

 /*

  * Initialize the event port implementation.

  */

 static void*

 evport_init(struct event_base *base)

 {

 	struct evport_data *evpd;

 	int i;

 	if (!(evpd = mm_calloc(1, sizeof(struct evport_data))))

 		return (NULL);

 	if ((evpd->ed_port = port_create()) == -1) {

 		mm_free(evpd);

 		return (NULL);

 	}

 	/*

 	 * Initialize file descriptor structure

 	 */

 	evpd->ed_fds = mm_calloc(DEFAULT_NFDS, sizeof(struct fd_info));

 	if (evpd->ed_fds == NULL) {

 		close(evpd->ed_port);

 		mm_free(evpd);

 		return (NULL);

 	}

 	evpd->ed_nevents = DEFAULT_NFDS;

 	for (i = 0; i < EVENTS_PER_GETN; i++)

 		evpd->ed_pending[i] = -1;

 	evsig_init(base);

 	return (evpd);

 }

 #ifdef CHECK_INVARIANTS

 /*

  * Checks some basic properties about the evport_data structure. Because it

  * checks all file descriptors, this function can be expensive when the maximum

  * file descriptor ever used is rather large.

  */

 static void

 check_evportop(struct evport_data *evpd)

 {

 	EVUTIL_ASSERT(evpd);

 	EVUTIL_ASSERT(evpd->ed_nevents > 0);

 	EVUTIL_ASSERT(evpd->ed_port > 0);

 	EVUTIL_ASSERT(evpd->ed_fds > 0);

 }

 /*

  * Verifies very basic integrity of a given port_event.

  */

 static void

 check_event(port_event_t* pevt)

 {

 	/*

 	 * We've only registered for PORT_SOURCE_FD events. The only

 	 * other thing we can legitimately receive is PORT_SOURCE_ALERT,

 	 * but since we're not using port_alert either, we can assume

 	 * PORT_SOURCE_FD.

 	 */

 	EVUTIL_ASSERT(pevt->portev_source == PORT_SOURCE_FD);

 	EVUTIL_ASSERT(pevt->portev_user == NULL);

 }

 #else

 #define check_evportop(epop)

 #define check_event(pevt)

 #endif /* CHECK_INVARIANTS */

 /*

  * Doubles the size of the allocated file descriptor array.

  */

 static int

 grow(struct evport_data *epdp, int factor)

 {

 	struct fd_info *tmp;

 	int oldsize = epdp->ed_nevents;

 	int newsize = factor * oldsize;

 	EVUTIL_ASSERT(factor > 1);

 	check_evportop(epdp);

 	tmp = mm_realloc(epdp->ed_fds, sizeof(struct fd_info) * newsize);

 	if (NULL == tmp)

 		return -1;

 	epdp->ed_fds = tmp;

 	memset((char*) (epdp->ed_fds + oldsize), 0,

 	    (newsize - oldsize)*sizeof(struct fd_info));

 	epdp->ed_nevents = newsize;

 	check_evportop(epdp);

 	return 0;

 }

 /*

  * (Re)associates the given file descriptor with the event port. The OS events

  * are specified (implicitly) from the fd_info struct.

  */

 static int

 reassociate(struct evport_data *epdp, struct fd_info *fdip, int fd)

 {

 	int sysevents = FDI_TO_SYSEVENTS(fdip);

 	if (sysevents != 0) {

 		if (port_associate(epdp->ed_port, PORT_SOURCE_FD,

 				   fd, sysevents, NULL) == -1) {

 			event_warn("port_associate");

 			return (-1);

 		}

 	}

 	check_evportop(epdp);

 	return (0);

 }

 /*

  * Main event loop - polls port_getn for some number of events, and processes

  * them.

  */

 static int

 evport_dispatch(struct event_base *base, struct timeval *tv)

 {

 	int i, res;

 	struct evport_data *epdp = base->evbase;

 	port_event_t pevtlist[EVENTS_PER_GETN];

 	/*

 	 * port_getn will block until it has at least nevents events. It will

 	 * also return how many it's given us (which may be more than we asked

 	 * for, as long as it's less than our maximum (EVENTS_PER_GETN)) in

 	 * nevents.

 	 */

 	int nevents = 1;

 	/*

 	 * We have to convert a struct timeval to a struct timespec

 	 * (only difference is nanoseconds vs. microseconds). If no time-based

 	 * events are active, we should wait for I/O (and tv == NULL).

 	 */

 	struct timespec ts;

 	struct timespec *ts_p = NULL;

 	if (tv != NULL) {

 		ts.tv_sec = tv->tv_sec;

 		ts.tv_nsec = tv->tv_usec * 1000;

 		ts_p = &ts;

 	}

 	/*

 	 * Before doing anything else, we need to reassociate the events we hit

 	 * last time which need reassociation. See comment at the end of the

 	 * loop below.

 	 */

 	for (i = 0; i < EVENTS_PER_GETN; ++i) {

 		struct fd_info *fdi = NULL;

 		if (epdp->ed_pending[i] != -1) {

 			fdi = &(epdp->ed_fds[epdp->ed_pending[i]]);

 		}

 		if (fdi != NULL && FDI_HAS_EVENTS(fdi)) {

 			int fd = epdp->ed_pending[i];

 			reassociate(epdp, fdi, fd);

 			epdp->ed_pending[i] = -1;

 		}

 	}

 	EVBASE_RELEASE_LOCK(base, th_base_lock);

 	res = port_getn(epdp->ed_port, pevtlist, EVENTS_PER_GETN,

 	    (unsigned int *) &nevents, ts_p);

 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);

 	if (res == -1) {

 		if (errno == EINTR || errno == EAGAIN) {

 			return (0);

 		} else if (errno == ETIME) {

 			if (nevents == 0)

 				return (0);

 		} else {

 			event_warn("port_getn");

 			return (-1);

 		}

 	}

 	event_debug(("%s: port_getn reports %d events", __func__, nevents));

 	for (i = 0; i < nevents; ++i) {

 		struct fd_info *fdi;

 		port_event_t *pevt = &pevtlist[i];

 		int fd = (int) pevt->portev_object;

 		check_evportop(epdp);

 		check_event(pevt);

 		epdp->ed_pending[i] = fd;

 		/*

 		 * Figure out what kind of event it was

 		 * (because we have to pass this to the callback)

 		 */

 		res = 0;

 		if (pevt->portev_events & (POLLERR|POLLHUP)) {

 			res = EV_READ | EV_WRITE;

 		} else {

 			if (pevt->portev_events & POLLIN)

 				res |= EV_READ;

 			if (pevt->portev_events & POLLOUT)

 				res |= EV_WRITE;

 		}

 		/*

 		 * Check for the error situations or a hangup situation

 		 */

 		if (pevt->portev_events & (POLLERR|POLLHUP|POLLNVAL))

 			res |= EV_READ|EV_WRITE;

 		EVUTIL_ASSERT(epdp->ed_nevents > fd);

 		fdi = &(epdp->ed_fds[fd]);

 		evmap_io_active(base, fd, res);

 	} /* end of all events gotten */

 	check_evportop(epdp);

 	return (0);

 }

 /*

  * Adds the given event (so that you will be notified when it happens via

  * the callback function).

  */

 static int

 evport_add(struct event_base *base, int fd, short old, short events, void *p)

 {

 	struct evport_data *evpd = base->evbase;

 	struct fd_info *fdi;

 	int factor;

 	(void)p;

 	check_evportop(evpd);

 	/*

 	 * If necessary, grow the file descriptor info table

 	 */

 	factor = 1;

 	while (fd >= factor * evpd->ed_nevents)

 		factor *= 2;

 	if (factor > 1) {

 		if (-1 == grow(evpd, factor)) {

 			return (-1);

 		}

 	}

 	fdi = &evpd->ed_fds[fd];

 	fdi->fdi_what |= events;

 	return reassociate(evpd, fdi, fd);

 }

 /*

  * Removes the given event from the list of events to wait for.

  */

 static int

 evport_del(struct event_base *base, int fd, short old, short events, void *p)

 {

 	struct evport_data *evpd = base->evbase;

 	struct fd_info *fdi;

 	int i;

 	int associated = 1;

 	(void)p;

 	check_evportop(evpd);

 	if (evpd->ed_nevents < fd) {

 		return (-1);

 	}

 	for (i = 0; i < EVENTS_PER_GETN; ++i) {

 		if (evpd->ed_pending[i] == fd) {

 			associated = 0;

 			break;

 		}

 	}

 	fdi = &evpd->ed_fds[fd];

 	if (events & EV_READ)

 		fdi->fdi_what &= ~EV_READ;

 	if (events & EV_WRITE)

 		fdi->fdi_what &= ~EV_WRITE;

 	if (associated) {

 		if (!FDI_HAS_EVENTS(fdi) &&

 		    port_dissociate(evpd->ed_port, PORT_SOURCE_FD, fd) == -1) {

 			/*

 			 * Ignore EBADFD error the fd could have been closed

 			 * before event_del() was called.

 			 */

 			if (errno != EBADFD) {

 				event_warn("port_dissociate");

 				return (-1);

 			}

 		} else {

 			if (FDI_HAS_EVENTS(fdi)) {

 				return (reassociate(evpd, fdi, fd));

 			}

 		}

 	} else {

 		if ((fdi->fdi_what & (EV_READ|EV_WRITE)) == 0) {

 			evpd->ed_pending[i] = -1;

 		}

 	}

 	return 0;

 }

 static void

 evport_dealloc(struct event_base *base)

 {

 	struct evport_data *evpd = base->evbase;

 	evsig_dealloc(base);

 	close(evpd->ed_port);

 	if (evpd->ed_fds)

 		mm_free(evpd->ed_fds);

 	mm_free(evpd);

 }