base/third_party/libevent/poll.c - gn - Git at Google

 /*	$OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $	*/

 /*
  * Copyright 2000-2003 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.
  */
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif

 #include <sys/types.h>
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
 #else
 #include <sys/_libevent_time.h>
 #endif
 #include <sys/queue.h>
 #include <poll.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
 #ifdef CHECK_INVARIANTS
 #include <assert.h>
 #endif

 #include "event.h"
 #include "event-internal.h"
 #include "evsignal.h"
 #include "log.h"

 struct pollop {
 	int event_count;		/* Highest number alloc */
 	int nfds;                       /* Size of event_* */
 	int fd_count;                   /* Size of idxplus1_by_fd */
 	struct pollfd *event_set;
 	struct event **event_r_back;
 	struct event **event_w_back;
 	int *idxplus1_by_fd; /* Index into event_set by fd; we add 1 so
 			      * that 0 (which is easy to memset) can mean
 			      * "no entry." */
 };

 static void *poll_init	(struct event_base *);
 static int poll_add		(void *, struct event *);
 static int poll_del		(void *, struct event *);
 static int poll_dispatch	(struct event_base *, void *, struct timeval *);
 static void poll_dealloc	(struct event_base *, void *);

 const struct eventop pollops = {
 	"poll",
 	poll_init,
 	poll_add,
 	poll_del,
 	poll_dispatch,
 	poll_dealloc,
     0
 };

 static void *
 poll_init(struct event_base *base)
 {
 	struct pollop *pollop;

 	/* Disable poll when this environment variable is set */
 	if (evutil_getenv("EVENT_NOPOLL"))
 		return (NULL);

 	if (!(pollop = calloc(1, sizeof(struct pollop))))
 		return (NULL);

 	evsignal_init(base);

 	return (pollop);
 }

 #ifdef CHECK_INVARIANTS
 static void
 poll_check_ok(struct pollop *pop)
 {
 	int i, idx;
 	struct event *ev;

 	for (i = 0; i < pop->fd_count; ++i) {
 		idx = pop->idxplus1_by_fd[i]-1;
 		if (idx < 0)
 			continue;
 		assert(pop->event_set[idx].fd == i);
 		if (pop->event_set[idx].events & POLLIN) {
 			ev = pop->event_r_back[idx];
 			assert(ev);
 			assert(ev->ev_events & EV_READ);
 			assert(ev->ev_fd == i);
 		}
 		if (pop->event_set[idx].events & POLLOUT) {
 			ev = pop->event_w_back[idx];
 			assert(ev);
 			assert(ev->ev_events & EV_WRITE);
 			assert(ev->ev_fd == i);
 		}
 	}
 	for (i = 0; i < pop->nfds; ++i) {
 		struct pollfd *pfd = &pop->event_set[i];
 		assert(pop->idxplus1_by_fd[pfd->fd] == i+1);
 	}
 }
 #else
 #define poll_check_ok(pop)
 #endif

 static int
 poll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
 {
 	int res, i, j, msec = -1, nfds;
 	struct pollop *pop = arg;

 	poll_check_ok(pop);

 	if (tv != NULL)
 		msec = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;

 	nfds = pop->nfds;
 	res = poll(pop->event_set, nfds, msec);

 	if (res == -1) {
 		if (errno != EINTR) {
                         event_warn("poll");
 			return (-1);
 		}

 		evsignal_process(base);
 		return (0);
 	} else if (base->sig.evsignal_caught) {
 		evsignal_process(base);
 	}

 	event_debug(("%s: poll reports %d", __func__, res));

 	if (res == 0 || nfds == 0)
 		return (0);

 	i = random() % nfds;
 	for (j = 0; j < nfds; j++) {
 		struct event *r_ev = NULL, *w_ev = NULL;
 		int what;
 		if (++i == nfds)
 			i = 0;
 		what = pop->event_set[i].revents;

 		if (!what)
 			continue;

 		res = 0;

 		/* If the file gets closed notify */
 		if (what & (POLLHUP|POLLERR))
 			what |= POLLIN|POLLOUT;
 		if (what & POLLIN) {
 			res |= EV_READ;
 			r_ev = pop->event_r_back[i];
 		}
 		if (what & POLLOUT) {
 			res |= EV_WRITE;
 			w_ev = pop->event_w_back[i];
 		}
 		if (res == 0)
 			continue;

 		if (r_ev && (res & r_ev->ev_events)) {
 			event_active(r_ev, res & r_ev->ev_events, 1);
 		}
 		if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
 			event_active(w_ev, res & w_ev->ev_events, 1);
 		}
 	}

 	return (0);
 }

 static int
 poll_add(void *arg, struct event *ev)
 {
 	struct pollop *pop = arg;
 	struct pollfd *pfd = NULL;
 	int i;

 	if (ev->ev_events & EV_SIGNAL)
 		return (evsignal_add(ev));
 	if (!(ev->ev_events & (EV_READ|EV_WRITE)))
 		return (0);

 	poll_check_ok(pop);
 	if (pop->nfds + 1 >= pop->event_count) {
 		struct pollfd *tmp_event_set;
 		struct event **tmp_event_r_back;
 		struct event **tmp_event_w_back;
 		int tmp_event_count;

 		if (pop->event_count < 32)
 			tmp_event_count = 32;
 		else
 			tmp_event_count = pop->event_count * 2;

 		/* We need more file descriptors */
 		tmp_event_set = realloc(pop->event_set,
 				 tmp_event_count * sizeof(struct pollfd));
 		if (tmp_event_set == NULL) {
 			event_warn("realloc");
 			return (-1);
 		}
 		pop->event_set = tmp_event_set;

 		tmp_event_r_back = realloc(pop->event_r_back,
 			    tmp_event_count * sizeof(struct event *));
 		if (tmp_event_r_back == NULL) {
 			/* event_set overallocated; that's okay. */
 			event_warn("realloc");
 			return (-1);
 		}
 		pop->event_r_back = tmp_event_r_back;

 		tmp_event_w_back = realloc(pop->event_w_back,
 			    tmp_event_count * sizeof(struct event *));
 		if (tmp_event_w_back == NULL) {
 			/* event_set and event_r_back overallocated; that's
 			 * okay. */
 			event_warn("realloc");
 			return (-1);
 		}
 		pop->event_w_back = tmp_event_w_back;

 		pop->event_count = tmp_event_count;
 	}
 	if (ev->ev_fd >= pop->fd_count) {
 		int *tmp_idxplus1_by_fd;
 		int new_count;
 		if (pop->fd_count < 32)
 			new_count = 32;
 		else
 			new_count = pop->fd_count * 2;
 		while (new_count <= ev->ev_fd)
 			new_count *= 2;
 		tmp_idxplus1_by_fd =
 			realloc(pop->idxplus1_by_fd, new_count * sizeof(int));
 		if (tmp_idxplus1_by_fd == NULL) {
 			event_warn("realloc");
 			return (-1);
 		}
 		pop->idxplus1_by_fd = tmp_idxplus1_by_fd;
 		memset(pop->idxplus1_by_fd + pop->fd_count,
 		       0, sizeof(int)*(new_count - pop->fd_count));
 		pop->fd_count = new_count;
 	}

 	i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
 	if (i >= 0) {
 		pfd = &pop->event_set[i];
 	} else {
 		i = pop->nfds++;
 		pfd = &pop->event_set[i];
 		pfd->events = 0;
 		pfd->fd = ev->ev_fd;
 		pop->event_w_back[i] = pop->event_r_back[i] = NULL;
 		pop->idxplus1_by_fd[ev->ev_fd] = i + 1;
 	}

 	pfd->revents = 0;
 	if (ev->ev_events & EV_WRITE) {
 		pfd->events |= POLLOUT;
 		pop->event_w_back[i] = ev;
 	}
 	if (ev->ev_events & EV_READ) {
 		pfd->events |= POLLIN;
 		pop->event_r_back[i] = ev;
 	}
 	poll_check_ok(pop);

 	return (0);
 }

 /*
  * Nothing to be done here.
  */

 static int
 poll_del(void *arg, struct event *ev)
 {
 	struct pollop *pop = arg;
 	struct pollfd *pfd = NULL;
 	int i;

 	if (ev->ev_events & EV_SIGNAL)
 		return (evsignal_del(ev));

 	if (!(ev->ev_events & (EV_READ|EV_WRITE)))
 		return (0);

 	poll_check_ok(pop);
 	i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
 	if (i < 0)
 		return (-1);

 	/* Do we still want to read or write? */
 	pfd = &pop->event_set[i];
 	if (ev->ev_events & EV_READ) {
 		pfd->events &= ~POLLIN;
 		pop->event_r_back[i] = NULL;
 	}
 	if (ev->ev_events & EV_WRITE) {
 		pfd->events &= ~POLLOUT;
 		pop->event_w_back[i] = NULL;
 	}
 	poll_check_ok(pop);
 	if (pfd->events)
 		/* Another event cares about that fd. */
 		return (0);

 	/* Okay, so we aren't interested in that fd anymore. */
 	pop->idxplus1_by_fd[ev->ev_fd] = 0;

 	--pop->nfds;
 	if (i != pop->nfds) {
 		/*
 		 * Shift the last pollfd down into the now-unoccupied
 		 * position.
 		 */
 		memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
 		       sizeof(struct pollfd));
 		pop->event_r_back[i] = pop->event_r_back[pop->nfds];
 		pop->event_w_back[i] = pop->event_w_back[pop->nfds];
 		pop->idxplus1_by_fd[pop->event_set[i].fd] = i + 1;
 	}

 	poll_check_ok(pop);
 	return (0);
 }

 static void
 poll_dealloc(struct event_base *base, void *arg)
 {
 	struct pollop *pop = arg;

 	evsignal_dealloc(base);
 	if (pop->event_set)
 		free(pop->event_set);
 	if (pop->event_r_back)
 		free(pop->event_r_back);
 	if (pop->event_w_back)
 		free(pop->event_w_back);
 	if (pop->idxplus1_by_fd)
 		free(pop->idxplus1_by_fd);

 	memset(pop, 0, sizeof(struct pollop));
 	free(pop);
 }
	/* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */

	/*
	* Copyright 2000-2003 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.
	*/
	#ifdef HAVE_CONFIG_H
	#include "config.h"
	#endif

	#include <sys/types.h>
	#ifdef HAVE_SYS_TIME_H
	#include <sys/time.h>
	#else
	#include <sys/_libevent_time.h>
	#endif
	#include <sys/queue.h>
	#include <poll.h>
	#include <signal.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <errno.h>
	#ifdef CHECK_INVARIANTS
	#include <assert.h>
	#endif

	#include "event.h"
	#include "event-internal.h"
	#include "evsignal.h"
	#include "log.h"

	struct pollop {
	int event_count; /* Highest number alloc */
	int nfds; /* Size of event_* */
	int fd_count; /* Size of idxplus1_by_fd */
	struct pollfd *event_set;
	struct event **event_r_back;
	struct event **event_w_back;
	int idxplus1_by_fd; / Index into event_set by fd; we add 1 so
	* that 0 (which is easy to memset) can mean
	* "no entry." */
	};

	static void poll_init (struct event_base );
	static int poll_add (void , struct event );
	static int poll_del (void , struct event );
	static int poll_dispatch (struct event_base , void , struct timeval *);
	static void poll_dealloc (struct event_base , void );

	const struct eventop pollops = {
	"poll",
	poll_init,
	poll_add,
	poll_del,
	poll_dispatch,
	poll_dealloc,
	0
	};

	static void *
	poll_init(struct event_base *base)
	{
	struct pollop *pollop;

	/* Disable poll when this environment variable is set */
	if (evutil_getenv("EVENT_NOPOLL"))
	return (NULL);

	if (!(pollop = calloc(1, sizeof(struct pollop))))
	return (NULL);

	evsignal_init(base);

	return (pollop);
	}

	#ifdef CHECK_INVARIANTS
	static void
	poll_check_ok(struct pollop *pop)
	{
	int i, idx;
	struct event *ev;

	for (i = 0; i < pop->fd_count; ++i) {
	idx = pop->idxplus1_by_fd[i]-1;
	if (idx < 0)
	continue;
	assert(pop->event_set[idx].fd == i);
	if (pop->event_set[idx].events & POLLIN) {
	ev = pop->event_r_back[idx];
	assert(ev);
	assert(ev->ev_events & EV_READ);
	assert(ev->ev_fd == i);
	}
	if (pop->event_set[idx].events & POLLOUT) {
	ev = pop->event_w_back[idx];
	assert(ev);
	assert(ev->ev_events & EV_WRITE);
	assert(ev->ev_fd == i);
	}
	}
	for (i = 0; i < pop->nfds; ++i) {
	struct pollfd *pfd = &pop->event_set[i];
	assert(pop->idxplus1_by_fd[pfd->fd] == i+1);
	}
	}
	#else
	#define poll_check_ok(pop)
	#endif

	static int
	poll_dispatch(struct event_base base, void arg, struct timeval *tv)
	{
	int res, i, j, msec = -1, nfds;
	struct pollop *pop = arg;

	poll_check_ok(pop);

	if (tv != NULL)
	msec = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;

	nfds = pop->nfds;
	res = poll(pop->event_set, nfds, msec);

	if (res == -1) {
	if (errno != EINTR) {
	event_warn("poll");
	return (-1);
	}

	evsignal_process(base);
	return (0);
	} else if (base->sig.evsignal_caught) {
	evsignal_process(base);
	}

	event_debug(("%s: poll reports %d", __func__, res));

	if (res == 0 \|\| nfds == 0)
	return (0);

	i = random() % nfds;
	for (j = 0; j < nfds; j++) {
	struct event r_ev = NULL, w_ev = NULL;
	int what;
	if (++i == nfds)
	i = 0;
	what = pop->event_set[i].revents;

	if (!what)
	continue;

	res = 0;

	/* If the file gets closed notify */
	if (what & (POLLHUP\|POLLERR))
	what \|= POLLIN\|POLLOUT;
	if (what & POLLIN) {
	res \|= EV_READ;
	r_ev = pop->event_r_back[i];
	}
	if (what & POLLOUT) {
	res \|= EV_WRITE;
	w_ev = pop->event_w_back[i];
	}
	if (res == 0)
	continue;

	if (r_ev && (res & r_ev->ev_events)) {
	event_active(r_ev, res & r_ev->ev_events, 1);
	}
	if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
	event_active(w_ev, res & w_ev->ev_events, 1);
	}
	}

	return (0);
	}

	static int
	poll_add(void arg, struct event ev)
	{
	struct pollop *pop = arg;
	struct pollfd *pfd = NULL;
	int i;

	if (ev->ev_events & EV_SIGNAL)
	return (evsignal_add(ev));
	if (!(ev->ev_events & (EV_READ\|EV_WRITE)))
	return (0);

	poll_check_ok(pop);
	if (pop->nfds + 1 >= pop->event_count) {
	struct pollfd *tmp_event_set;
	struct event **tmp_event_r_back;
	struct event **tmp_event_w_back;
	int tmp_event_count;

	if (pop->event_count < 32)
	tmp_event_count = 32;
	else
	tmp_event_count = pop->event_count * 2;

	/* We need more file descriptors */
	tmp_event_set = realloc(pop->event_set,
	tmp_event_count * sizeof(struct pollfd));
	if (tmp_event_set == NULL) {
	event_warn("realloc");
	return (-1);
	}
	pop->event_set = tmp_event_set;

	tmp_event_r_back = realloc(pop->event_r_back,
	tmp_event_count * sizeof(struct event *));
	if (tmp_event_r_back == NULL) {
	/* event_set overallocated; that's okay. */
	event_warn("realloc");
	return (-1);
	}
	pop->event_r_back = tmp_event_r_back;

	tmp_event_w_back = realloc(pop->event_w_back,
	tmp_event_count * sizeof(struct event *));
	if (tmp_event_w_back == NULL) {
	/* event_set and event_r_back overallocated; that's
	* okay. */
	event_warn("realloc");
	return (-1);
	}
	pop->event_w_back = tmp_event_w_back;

	pop->event_count = tmp_event_count;
	}
	if (ev->ev_fd >= pop->fd_count) {
	int *tmp_idxplus1_by_fd;
	int new_count;
	if (pop->fd_count < 32)
	new_count = 32;
	else
	new_count = pop->fd_count * 2;
	while (new_count <= ev->ev_fd)
	new_count *= 2;
	tmp_idxplus1_by_fd =
	realloc(pop->idxplus1_by_fd, new_count * sizeof(int));
	if (tmp_idxplus1_by_fd == NULL) {
	event_warn("realloc");
	return (-1);
	}
	pop->idxplus1_by_fd = tmp_idxplus1_by_fd;
	memset(pop->idxplus1_by_fd + pop->fd_count,
	0, sizeof(int)*(new_count - pop->fd_count));
	pop->fd_count = new_count;
	}

	i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
	if (i >= 0) {
	pfd = &pop->event_set[i];
	} else {
	i = pop->nfds++;
	pfd = &pop->event_set[i];
	pfd->events = 0;
	pfd->fd = ev->ev_fd;
	pop->event_w_back[i] = pop->event_r_back[i] = NULL;
	pop->idxplus1_by_fd[ev->ev_fd] = i + 1;
	}

	pfd->revents = 0;
	if (ev->ev_events & EV_WRITE) {
	pfd->events \|= POLLOUT;
	pop->event_w_back[i] = ev;
	}
	if (ev->ev_events & EV_READ) {
	pfd->events \|= POLLIN;
	pop->event_r_back[i] = ev;
	}
	poll_check_ok(pop);

	return (0);
	}

	/*
	* Nothing to be done here.
	*/

	static int
	poll_del(void arg, struct event ev)
	{
	struct pollop *pop = arg;
	struct pollfd *pfd = NULL;
	int i;

	if (ev->ev_events & EV_SIGNAL)
	return (evsignal_del(ev));

	if (!(ev->ev_events & (EV_READ\|EV_WRITE)))
	return (0);

	poll_check_ok(pop);
	i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
	if (i < 0)
	return (-1);

	/* Do we still want to read or write? */
	pfd = &pop->event_set[i];
	if (ev->ev_events & EV_READ) {
	pfd->events &= ~POLLIN;
	pop->event_r_back[i] = NULL;
	}
	if (ev->ev_events & EV_WRITE) {
	pfd->events &= ~POLLOUT;
	pop->event_w_back[i] = NULL;
	}
	poll_check_ok(pop);
	if (pfd->events)
	/* Another event cares about that fd. */
	return (0);

	/* Okay, so we aren't interested in that fd anymore. */
	pop->idxplus1_by_fd[ev->ev_fd] = 0;

	--pop->nfds;
	if (i != pop->nfds) {
	/*
	* Shift the last pollfd down into the now-unoccupied
	* position.
	*/
	memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
	sizeof(struct pollfd));
	pop->event_r_back[i] = pop->event_r_back[pop->nfds];
	pop->event_w_back[i] = pop->event_w_back[pop->nfds];
	pop->idxplus1_by_fd[pop->event_set[i].fd] = i + 1;
	}

	poll_check_ok(pop);
	return (0);
	}

	static void
	poll_dealloc(struct event_base base, void arg)
	{
	struct pollop *pop = arg;

	evsignal_dealloc(base);
	if (pop->event_set)
	free(pop->event_set);
	if (pop->event_r_back)
	free(pop->event_r_back);
	if (pop->event_w_back)
	free(pop->event_w_back);
	if (pop->idxplus1_by_fd)
	free(pop->idxplus1_by_fd);

	memset(pop, 0, sizeof(struct pollop));
	free(pop);
	}