michael@0: /*	$OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $	*/
michael@0: 
michael@0: /*
michael@0:  * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
michael@0:  * Copyright 2007-2012 Niels Provos and Nick Mathewson
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1. Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  * 3. The name of the author may not be used to endorse or promote products
michael@0:  *    derived from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
michael@0:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
michael@0:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
michael@0:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
michael@0:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
michael@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: #include "event2/event-config.h"
michael@0: 
michael@0: #include <sys/types.h>
michael@0: #ifdef _EVENT_HAVE_SYS_TIME_H
michael@0: #include <sys/time.h>
michael@0: #endif
michael@0: #include <sys/queue.h>
michael@0: #include <poll.h>
michael@0: #include <signal.h>
michael@0: #include <limits.h>
michael@0: #include <stdio.h>
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: #include <unistd.h>
michael@0: #include <errno.h>
michael@0: 
michael@0: #include "event-internal.h"
michael@0: #include "evsignal-internal.h"
michael@0: #include "log-internal.h"
michael@0: #include "evmap-internal.h"
michael@0: #include "event2/thread.h"
michael@0: #include "evthread-internal.h"
michael@0: 
michael@0: struct pollidx {
michael@0: 	int idxplus1;
michael@0: };
michael@0: 
michael@0: struct pollop {
michael@0: 	int event_count;		/* Highest number alloc */
michael@0: 	int nfds;			/* Highest number used */
michael@0: 	int realloc_copy;		/* True iff we must realloc
michael@0: 					 * event_set_copy */
michael@0: 	struct pollfd *event_set;
michael@0: 	struct pollfd *event_set_copy;
michael@0: };
michael@0: 
michael@0: static void *poll_init(struct event_base *);
michael@0: static int poll_add(struct event_base *, int, short old, short events, void *_idx);
michael@0: static int poll_del(struct event_base *, int, short old, short events, void *_idx);
michael@0: static int poll_dispatch(struct event_base *, struct timeval *);
michael@0: static void poll_dealloc(struct event_base *);
michael@0: 
michael@0: const struct eventop pollops = {
michael@0: 	"poll",
michael@0: 	poll_init,
michael@0: 	poll_add,
michael@0: 	poll_del,
michael@0: 	poll_dispatch,
michael@0: 	poll_dealloc,
michael@0: 	0, /* doesn't need_reinit */
michael@0: 	EV_FEATURE_FDS,
michael@0: 	sizeof(struct pollidx),
michael@0: };
michael@0: 
michael@0: static void *
michael@0: poll_init(struct event_base *base)
michael@0: {
michael@0: 	struct pollop *pollop;
michael@0: 
michael@0: 	if (!(pollop = mm_calloc(1, sizeof(struct pollop))))
michael@0: 		return (NULL);
michael@0: 
michael@0: 	evsig_init(base);
michael@0: 
michael@0: 	return (pollop);
michael@0: }
michael@0: 
michael@0: #ifdef CHECK_INVARIANTS
michael@0: static void
michael@0: poll_check_ok(struct pollop *pop)
michael@0: {
michael@0: 	int i, idx;
michael@0: 	struct event *ev;
michael@0: 
michael@0: 	for (i = 0; i < pop->fd_count; ++i) {
michael@0: 		idx = pop->idxplus1_by_fd[i]-1;
michael@0: 		if (idx < 0)
michael@0: 			continue;
michael@0: 		EVUTIL_ASSERT(pop->event_set[idx].fd == i);
michael@0: 	}
michael@0: 	for (i = 0; i < pop->nfds; ++i) {
michael@0: 		struct pollfd *pfd = &pop->event_set[i];
michael@0: 		EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1);
michael@0: 	}
michael@0: }
michael@0: #else
michael@0: #define poll_check_ok(pop)
michael@0: #endif
michael@0: 
michael@0: static int
michael@0: poll_dispatch(struct event_base *base, struct timeval *tv)
michael@0: {
michael@0: 	int res, i, j, nfds;
michael@0: 	long msec = -1;
michael@0: 	struct pollop *pop = base->evbase;
michael@0: 	struct pollfd *event_set;
michael@0: 
michael@0: 	poll_check_ok(pop);
michael@0: 
michael@0: 	nfds = pop->nfds;
michael@0: 
michael@0: #ifndef _EVENT_DISABLE_THREAD_SUPPORT
michael@0: 	if (base->th_base_lock) {
michael@0: 		/* If we're using this backend in a multithreaded setting,
michael@0: 		 * then we need to work on a copy of event_set, so that we can
michael@0: 		 * let other threads modify the main event_set while we're
michael@0: 		 * polling. If we're not multithreaded, then we'll skip the
michael@0: 		 * copy step here to save memory and time. */
michael@0: 		if (pop->realloc_copy) {
michael@0: 			struct pollfd *tmp = mm_realloc(pop->event_set_copy,
michael@0: 			    pop->event_count * sizeof(struct pollfd));
michael@0: 			if (tmp == NULL) {
michael@0: 				event_warn("realloc");
michael@0: 				return -1;
michael@0: 			}
michael@0: 			pop->event_set_copy = tmp;
michael@0: 			pop->realloc_copy = 0;
michael@0: 		}
michael@0: 		memcpy(pop->event_set_copy, pop->event_set,
michael@0: 		    sizeof(struct pollfd)*nfds);
michael@0: 		event_set = pop->event_set_copy;
michael@0: 	} else {
michael@0: 		event_set = pop->event_set;
michael@0: 	}
michael@0: #else
michael@0: 	event_set = pop->event_set;
michael@0: #endif
michael@0: 
michael@0: 	if (tv != NULL) {
michael@0: 		msec = evutil_tv_to_msec(tv);
michael@0: 		if (msec < 0 || msec > INT_MAX)
michael@0: 			msec = INT_MAX;
michael@0: 	}
michael@0: 
michael@0: 	EVBASE_RELEASE_LOCK(base, th_base_lock);
michael@0: 
michael@0: 	res = poll(event_set, nfds, msec);
michael@0: 
michael@0: 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
michael@0: 
michael@0: 	if (res == -1) {
michael@0: 		if (errno != EINTR) {
michael@0: 			event_warn("poll");
michael@0: 			return (-1);
michael@0: 		}
michael@0: 
michael@0: 		return (0);
michael@0: 	}
michael@0: 
michael@0: 	event_debug(("%s: poll reports %d", __func__, res));
michael@0: 
michael@0: 	if (res == 0 || nfds == 0)
michael@0: 		return (0);
michael@0: 
michael@0: 	i = random() % nfds;
michael@0: 	for (j = 0; j < nfds; j++) {
michael@0: 		int what;
michael@0: 		if (++i == nfds)
michael@0: 			i = 0;
michael@0: 		what = event_set[i].revents;
michael@0: 		if (!what)
michael@0: 			continue;
michael@0: 
michael@0: 		res = 0;
michael@0: 
michael@0: 		/* If the file gets closed notify */
michael@0: 		if (what & (POLLHUP|POLLERR))
michael@0: 			what |= POLLIN|POLLOUT;
michael@0: 		if (what & POLLIN)
michael@0: 			res |= EV_READ;
michael@0: 		if (what & POLLOUT)
michael@0: 			res |= EV_WRITE;
michael@0: 		if (res == 0)
michael@0: 			continue;
michael@0: 
michael@0: 		evmap_io_active(base, event_set[i].fd, res);
michael@0: 	}
michael@0: 
michael@0: 	return (0);
michael@0: }
michael@0: 
michael@0: static int
michael@0: poll_add(struct event_base *base, int fd, short old, short events, void *_idx)
michael@0: {
michael@0: 	struct pollop *pop = base->evbase;
michael@0: 	struct pollfd *pfd = NULL;
michael@0: 	struct pollidx *idx = _idx;
michael@0: 	int i;
michael@0: 
michael@0: 	EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
michael@0: 	if (!(events & (EV_READ|EV_WRITE)))
michael@0: 		return (0);
michael@0: 
michael@0: 	poll_check_ok(pop);
michael@0: 	if (pop->nfds + 1 >= pop->event_count) {
michael@0: 		struct pollfd *tmp_event_set;
michael@0: 		int tmp_event_count;
michael@0: 
michael@0: 		if (pop->event_count < 32)
michael@0: 			tmp_event_count = 32;
michael@0: 		else
michael@0: 			tmp_event_count = pop->event_count * 2;
michael@0: 
michael@0: 		/* We need more file descriptors */
michael@0: 		tmp_event_set = mm_realloc(pop->event_set,
michael@0: 				 tmp_event_count * sizeof(struct pollfd));
michael@0: 		if (tmp_event_set == NULL) {
michael@0: 			event_warn("realloc");
michael@0: 			return (-1);
michael@0: 		}
michael@0: 		pop->event_set = tmp_event_set;
michael@0: 
michael@0: 		pop->event_count = tmp_event_count;
michael@0: 		pop->realloc_copy = 1;
michael@0: 	}
michael@0: 
michael@0: 	i = idx->idxplus1 - 1;
michael@0: 
michael@0: 	if (i >= 0) {
michael@0: 		pfd = &pop->event_set[i];
michael@0: 	} else {
michael@0: 		i = pop->nfds++;
michael@0: 		pfd = &pop->event_set[i];
michael@0: 		pfd->events = 0;
michael@0: 		pfd->fd = fd;
michael@0: 		idx->idxplus1 = i + 1;
michael@0: 	}
michael@0: 
michael@0: 	pfd->revents = 0;
michael@0: 	if (events & EV_WRITE)
michael@0: 		pfd->events |= POLLOUT;
michael@0: 	if (events & EV_READ)
michael@0: 		pfd->events |= POLLIN;
michael@0: 	poll_check_ok(pop);
michael@0: 
michael@0: 	return (0);
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * Nothing to be done here.
michael@0:  */
michael@0: 
michael@0: static int
michael@0: poll_del(struct event_base *base, int fd, short old, short events, void *_idx)
michael@0: {
michael@0: 	struct pollop *pop = base->evbase;
michael@0: 	struct pollfd *pfd = NULL;
michael@0: 	struct pollidx *idx = _idx;
michael@0: 	int i;
michael@0: 
michael@0: 	EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
michael@0: 	if (!(events & (EV_READ|EV_WRITE)))
michael@0: 		return (0);
michael@0: 
michael@0: 	poll_check_ok(pop);
michael@0: 	i = idx->idxplus1 - 1;
michael@0: 	if (i < 0)
michael@0: 		return (-1);
michael@0: 
michael@0: 	/* Do we still want to read or write? */
michael@0: 	pfd = &pop->event_set[i];
michael@0: 	if (events & EV_READ)
michael@0: 		pfd->events &= ~POLLIN;
michael@0: 	if (events & EV_WRITE)
michael@0: 		pfd->events &= ~POLLOUT;
michael@0: 	poll_check_ok(pop);
michael@0: 	if (pfd->events)
michael@0: 		/* Another event cares about that fd. */
michael@0: 		return (0);
michael@0: 
michael@0: 	/* Okay, so we aren't interested in that fd anymore. */
michael@0: 	idx->idxplus1 = 0;
michael@0: 
michael@0: 	--pop->nfds;
michael@0: 	if (i != pop->nfds) {
michael@0: 		/*
michael@0: 		 * Shift the last pollfd down into the now-unoccupied
michael@0: 		 * position.
michael@0: 		 */
michael@0: 		memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
michael@0: 		       sizeof(struct pollfd));
michael@0: 		idx = evmap_io_get_fdinfo(&base->io, pop->event_set[i].fd);
michael@0: 		EVUTIL_ASSERT(idx);
michael@0: 		EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1);
michael@0: 		idx->idxplus1 = i + 1;
michael@0: 	}
michael@0: 
michael@0: 	poll_check_ok(pop);
michael@0: 	return (0);
michael@0: }
michael@0: 
michael@0: static void
michael@0: poll_dealloc(struct event_base *base)
michael@0: {
michael@0: 	struct pollop *pop = base->evbase;
michael@0: 
michael@0: 	evsig_dealloc(base);
michael@0: 	if (pop->event_set)
michael@0: 		mm_free(pop->event_set);
michael@0: 	if (pop->event_set_copy)
michael@0: 		mm_free(pop->event_set_copy);
michael@0: 
michael@0: 	memset(pop, 0, sizeof(struct pollop));
michael@0: 	mm_free(pop);
michael@0: }