src/third_party/libevent/epoll.c - cobalt - Git at Google

 /*
  * 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 <stdint.h>
 #include <sys/types.h>
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
 #else
 #include <sys/_libevent_time.h>
 #endif
 #include <sys/queue.h>
 #ifndef STARBOARD
 #include <signal.h>
 #include <sys/epoll.h>
 #include <sys/resource.h>
 #endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
 #ifdef HAVE_FCNTL_H
 #include <fcntl.h>
 #endif

 #include "event.h"
 #include "event-internal.h"
 #ifndef STARBOARD
 #include "evsignal.h"
 #endif
 #include "log.h"

 #ifdef STARBOARD
 #include "epoll-internal.h"
 #endif

 /* due to limitations in the epoll interface, we need to keep track of
  * all file descriptors outself.
  */
 struct evepoll {
 	struct event *evread;
 	struct event *evwrite;
 };

 struct epollop {
 	struct evepoll *fds;
 	int nfds;
 	struct epoll_event *events;
 	int nevents;
 	int epfd;
 };

 static void *epoll_init	(struct event_base *);
 static int epoll_add	(void *, struct event *);
 static int epoll_del	(void *, struct event *);
 static int epoll_dispatch	(struct event_base *, void *, struct timeval *);
 static void epoll_dealloc	(struct event_base *, void *);

 const struct eventop epollops = {
 	"epoll",
 	epoll_init,
 	epoll_add,
 	epoll_del,
 	epoll_dispatch,
 	epoll_dealloc,
 	1 /* need reinit */
 };

 #ifdef HAVE_SETFD
 #define FD_CLOSEONEXEC(x) do { \
         if (fcntl(x, F_SETFD, 1) == -1) \
                 event_warn("fcntl(%d, F_SETFD)", x); \
 } while (0)
 #else
 #define FD_CLOSEONEXEC(x)
 #endif

 /* On Linux kernels at least up to 2.6.24.4, epoll can't handle timeout
  * values bigger than (LONG_MAX - 999ULL)/HZ.  HZ in the wild can be
  * as big as 1000, and LONG_MAX can be as small as (1<<31)-1, so the
  * largest number of msec we can support here is 2147482.  Let's
  * round that down by 47 seconds.
  */
 #define MAX_EPOLL_TIMEOUT_MSEC (35*60*1000)

 #define INITIAL_NFILES 32
 #define INITIAL_NEVENTS 32
 #define MAX_NEVENTS 4096

 static void *
 epoll_init(struct event_base *base)
 {
 	int epfd;
 	struct epollop *epollop;

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

 	/* Initalize the kernel queue */
 	if ((epfd = epoll_create(32000)) == -1) {
 		if (errno != ENOSYS)
 			event_warn("epoll_create");
 		return (NULL);
 	}

 	FD_CLOSEONEXEC(epfd);

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

 	epollop->epfd = epfd;

 	/* Initalize fields */
 	epollop->events = malloc(INITIAL_NEVENTS * sizeof(struct epoll_event));
 	if (epollop->events == NULL) {
 		free(epollop);
 		return (NULL);
 	}
 	epollop->nevents = INITIAL_NEVENTS;

 	epollop->fds = calloc(INITIAL_NFILES, sizeof(struct evepoll));
 	if (epollop->fds == NULL) {
 		free(epollop->events);
 		free(epollop);
 		return (NULL);
 	}
 	epollop->nfds = INITIAL_NFILES;

 #ifndef STARBOARD
 	evsignal_init(base);
 #endif

 	return (epollop);
 }

 static int
 epoll_recalc(struct event_base *base, void *arg, int max)
 {
 	struct epollop *epollop = arg;

 	if (max >= epollop->nfds) {
 		struct evepoll *fds;
 		int nfds;

 		nfds = epollop->nfds;
 		while (nfds <= max)
 			nfds <<= 1;

 		fds = realloc(epollop->fds, nfds * sizeof(struct evepoll));
 		if (fds == NULL) {
 			event_warn("realloc");
 			return (-1);
 		}
 		epollop->fds = fds;
 		memset(fds + epollop->nfds, 0,
 		    (nfds - epollop->nfds) * sizeof(struct evepoll));
 		epollop->nfds = nfds;
 	}

 	return (0);
 }

 static int
 epoll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
 {
 	struct epollop *epollop = arg;
 	struct epoll_event *events = epollop->events;
 	struct evepoll *evep;
 	int i, res, timeout = -1;

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

 	if (timeout > MAX_EPOLL_TIMEOUT_MSEC) {
 		/* Linux kernels can wait forever if the timeout is too big;
 		 * see comment on MAX_EPOLL_TIMEOUT_MSEC. */
 		timeout = MAX_EPOLL_TIMEOUT_MSEC;
 	}

 	res = epoll_wait(epollop->epfd, events, epollop->nevents, timeout);

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

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

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

 	for (i = 0; i < res; i++) {
 		int what = events[i].events;
 		struct event *evread = NULL, *evwrite = NULL;
 		int fd = events[i].data.fd;

 		if (fd < 0 || fd >= epollop->nfds)
 			continue;
 		evep = &epollop->fds[fd];

 		if (what & (EPOLLHUP|EPOLLERR)) {
 			evread = evep->evread;
 			evwrite = evep->evwrite;
 		} else {
 			if (what & EPOLLIN) {
 				evread = evep->evread;
 			}

 			if (what & EPOLLOUT) {
 				evwrite = evep->evwrite;
 			}
 		}

 		if (!(evread||evwrite))
 			continue;

 		if (evread != NULL)
 			event_active(evread, EV_READ, 1);
 		if (evwrite != NULL)
 			event_active(evwrite, EV_WRITE, 1);
 	}

 	if (res == epollop->nevents && epollop->nevents < MAX_NEVENTS) {
 		/* We used all of the event space this time.  We should
 		   be ready for more events next time. */
 		int new_nevents = epollop->nevents * 2;
 		struct epoll_event *new_events;

 		new_events = realloc(epollop->events,
 		    new_nevents * sizeof(struct epoll_event));
 		if (new_events) {
 			epollop->events = new_events;
 			epollop->nevents = new_nevents;
 		}
 	}

 	return (0);
 }


 static int
 epoll_add(void *arg, struct event *ev)
 {
 	struct epollop *epollop = arg;
 	struct epoll_event epev = {0};
 	struct evepoll *evep;
 	int fd, op, events;

 #ifndef STARBOARD
 	if (ev->ev_events & EV_SIGNAL)
 		return (evsignal_add(ev));
 #endif

 	fd = ev->ev_fd;
 	if (fd >= epollop->nfds) {
 		/* Extent the file descriptor array as necessary */
 		if (epoll_recalc(ev->ev_base, epollop, fd) == -1)
 			return (-1);
 	}
 	evep = &epollop->fds[fd];
 	op = EPOLL_CTL_ADD;
 	events = 0;
 	if (evep->evread != NULL) {
 		events |= EPOLLIN;
 		op = EPOLL_CTL_MOD;
 	}
 	if (evep->evwrite != NULL) {
 		events |= EPOLLOUT;
 		op = EPOLL_CTL_MOD;
 	}

 	if (ev->ev_events & EV_READ)
 		events |= EPOLLIN;
 	if (ev->ev_events & EV_WRITE)
 		events |= EPOLLOUT;

 	epev.data.fd = fd;
 	epev.events = events;
 	if (epoll_ctl(epollop->epfd, op, ev->ev_fd, &epev) == -1)
 			return (-1);

 	/* Update events responsible */
 	if (ev->ev_events & EV_READ)
 		evep->evread = ev;
 	if (ev->ev_events & EV_WRITE)
 		evep->evwrite = ev;

 	return (0);
 }

 static int
 epoll_del(void *arg, struct event *ev)
 {
 	struct epollop *epollop = arg;
 	struct epoll_event epev = {0};
 	struct evepoll *evep;
 	int fd, events, op;
 	int needwritedelete = 1, needreaddelete = 1;

 #ifndef STARBOARD
 	if (ev->ev_events & EV_SIGNAL)
 		return (evsignal_del(ev));
 #endif

 	fd = ev->ev_fd;
 	if (fd >= epollop->nfds)
 		return (0);
 	evep = &epollop->fds[fd];

 	op = EPOLL_CTL_DEL;
 	events = 0;

 	if (ev->ev_events & EV_READ)
 		events |= EPOLLIN;
 	if (ev->ev_events & EV_WRITE)
 		events |= EPOLLOUT;

 	if ((events & (EPOLLIN|EPOLLOUT)) != (EPOLLIN|EPOLLOUT)) {
 		if ((events & EPOLLIN) && evep->evwrite != NULL) {
 			needwritedelete = 0;
 			events = EPOLLOUT;
 			op = EPOLL_CTL_MOD;
 		} else if ((events & EPOLLOUT) && evep->evread != NULL) {
 			needreaddelete = 0;
 			events = EPOLLIN;
 			op = EPOLL_CTL_MOD;
 		}
 	}

 	epev.events = events;
 	epev.data.fd = fd;

 	if (needreaddelete)
 		evep->evread = NULL;
 	if (needwritedelete)
 		evep->evwrite = NULL;

 #ifdef STARBOARD
 	if (epoll_ctl_del(epollop->epfd, op, fd, &epev) == -1)
 #else
 	if (epoll_ctl(epollop->epfd, op, fd, &epev) == -1)
 #endif
 		return (-1);

 	return (0);
 }

 static void
 epoll_dealloc(struct event_base *base, void *arg)
 {
 	struct epollop *epollop = arg;

 #ifndef STARBOARD
 	evsignal_dealloc(base);
 #endif
 	if (epollop->fds)
 		free(epollop->fds);
 	if (epollop->events)
 		free(epollop->events);
 	if (epollop->epfd >= 0)
 		close(epollop->epfd);

 	memset(epollop, 0, sizeof(struct epollop));
 	free(epollop);
 }
	/*
	* 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 <stdint.h>
	#include <sys/types.h>
	#ifdef HAVE_SYS_TIME_H
	#include <sys/time.h>
	#else
	#include <sys/_libevent_time.h>
	#endif
	#include <sys/queue.h>
	#ifndef STARBOARD
	#include <signal.h>
	#include <sys/epoll.h>
	#include <sys/resource.h>
	#endif
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <errno.h>
	#ifdef HAVE_FCNTL_H
	#include <fcntl.h>
	#endif

	#include "event.h"
	#include "event-internal.h"
	#ifndef STARBOARD
	#include "evsignal.h"
	#endif
	#include "log.h"

	#ifdef STARBOARD
	#include "epoll-internal.h"
	#endif

	/* due to limitations in the epoll interface, we need to keep track of
	* all file descriptors outself.
	*/
	struct evepoll {
	struct event *evread;
	struct event *evwrite;
	};

	struct epollop {
	struct evepoll *fds;
	int nfds;
	struct epoll_event *events;
	int nevents;
	int epfd;
	};

	static void epoll_init (struct event_base );
	static int epoll_add (void , struct event );
	static int epoll_del (void , struct event );
	static int epoll_dispatch (struct event_base , void , struct timeval *);
	static void epoll_dealloc (struct event_base , void );

	const struct eventop epollops = {
	"epoll",
	epoll_init,
	epoll_add,
	epoll_del,
	epoll_dispatch,
	epoll_dealloc,
	1 /* need reinit */
	};

	#ifdef HAVE_SETFD
	#define FD_CLOSEONEXEC(x) do { \
	if (fcntl(x, F_SETFD, 1) == -1) \
	event_warn("fcntl(%d, F_SETFD)", x); \
	} while (0)
	#else
	#define FD_CLOSEONEXEC(x)
	#endif

	/* On Linux kernels at least up to 2.6.24.4, epoll can't handle timeout
	* values bigger than (LONG_MAX - 999ULL)/HZ. HZ in the wild can be
	* as big as 1000, and LONG_MAX can be as small as (1<<31)-1, so the
	* largest number of msec we can support here is 2147482. Let's
	* round that down by 47 seconds.
	*/
	#define MAX_EPOLL_TIMEOUT_MSEC (35601000)

	#define INITIAL_NFILES 32
	#define INITIAL_NEVENTS 32
	#define MAX_NEVENTS 4096

	static void *
	epoll_init(struct event_base *base)
	{
	int epfd;
	struct epollop *epollop;

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

	/* Initalize the kernel queue */
	if ((epfd = epoll_create(32000)) == -1) {
	if (errno != ENOSYS)
	event_warn("epoll_create");
	return (NULL);
	}

	FD_CLOSEONEXEC(epfd);

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

	epollop->epfd = epfd;

	/* Initalize fields */
	epollop->events = malloc(INITIAL_NEVENTS * sizeof(struct epoll_event));
	if (epollop->events == NULL) {
	free(epollop);
	return (NULL);
	}
	epollop->nevents = INITIAL_NEVENTS;

	epollop->fds = calloc(INITIAL_NFILES, sizeof(struct evepoll));
	if (epollop->fds == NULL) {
	free(epollop->events);
	free(epollop);
	return (NULL);
	}
	epollop->nfds = INITIAL_NFILES;

	#ifndef STARBOARD
	evsignal_init(base);
	#endif

	return (epollop);
	}

	static int
	epoll_recalc(struct event_base base, void arg, int max)
	{
	struct epollop *epollop = arg;

	if (max >= epollop->nfds) {
	struct evepoll *fds;
	int nfds;

	nfds = epollop->nfds;
	while (nfds <= max)
	nfds <<= 1;

	fds = realloc(epollop->fds, nfds * sizeof(struct evepoll));
	if (fds == NULL) {
	event_warn("realloc");
	return (-1);
	}
	epollop->fds = fds;
	memset(fds + epollop->nfds, 0,
	(nfds - epollop->nfds) * sizeof(struct evepoll));
	epollop->nfds = nfds;
	}

	return (0);
	}

	static int
	epoll_dispatch(struct event_base base, void arg, struct timeval *tv)
	{
	struct epollop *epollop = arg;
	struct epoll_event *events = epollop->events;
	struct evepoll *evep;
	int i, res, timeout = -1;

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

	if (timeout > MAX_EPOLL_TIMEOUT_MSEC) {
	/* Linux kernels can wait forever if the timeout is too big;
	* see comment on MAX_EPOLL_TIMEOUT_MSEC. */
	timeout = MAX_EPOLL_TIMEOUT_MSEC;
	}

	res = epoll_wait(epollop->epfd, events, epollop->nevents, timeout);

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

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

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

	for (i = 0; i < res; i++) {
	int what = events[i].events;
	struct event evread = NULL, evwrite = NULL;
	int fd = events[i].data.fd;

	if (fd < 0 \|\| fd >= epollop->nfds)
	continue;
	evep = &epollop->fds[fd];

	if (what & (EPOLLHUP\|EPOLLERR)) {
	evread = evep->evread;
	evwrite = evep->evwrite;
	} else {
	if (what & EPOLLIN) {
	evread = evep->evread;
	}

	if (what & EPOLLOUT) {
	evwrite = evep->evwrite;
	}
	}

	if (!(evread\|\|evwrite))
	continue;

	if (evread != NULL)
	event_active(evread, EV_READ, 1);
	if (evwrite != NULL)
	event_active(evwrite, EV_WRITE, 1);
	}

	if (res == epollop->nevents && epollop->nevents < MAX_NEVENTS) {
	/* We used all of the event space this time. We should
	be ready for more events next time. */
	int new_nevents = epollop->nevents * 2;
	struct epoll_event *new_events;

	new_events = realloc(epollop->events,
	new_nevents * sizeof(struct epoll_event));
	if (new_events) {
	epollop->events = new_events;
	epollop->nevents = new_nevents;
	}
	}

	return (0);
	}


	static int
	epoll_add(void arg, struct event ev)
	{
	struct epollop *epollop = arg;
	struct epoll_event epev = {0};
	struct evepoll *evep;
	int fd, op, events;

	#ifndef STARBOARD
	if (ev->ev_events & EV_SIGNAL)
	return (evsignal_add(ev));
	#endif

	fd = ev->ev_fd;
	if (fd >= epollop->nfds) {
	/* Extent the file descriptor array as necessary */
	if (epoll_recalc(ev->ev_base, epollop, fd) == -1)
	return (-1);
	}
	evep = &epollop->fds[fd];
	op = EPOLL_CTL_ADD;
	events = 0;
	if (evep->evread != NULL) {
	events \|= EPOLLIN;
	op = EPOLL_CTL_MOD;
	}
	if (evep->evwrite != NULL) {
	events \|= EPOLLOUT;
	op = EPOLL_CTL_MOD;
	}

	if (ev->ev_events & EV_READ)
	events \|= EPOLLIN;
	if (ev->ev_events & EV_WRITE)
	events \|= EPOLLOUT;

	epev.data.fd = fd;
	epev.events = events;
	if (epoll_ctl(epollop->epfd, op, ev->ev_fd, &epev) == -1)
	return (-1);

	/* Update events responsible */
	if (ev->ev_events & EV_READ)
	evep->evread = ev;
	if (ev->ev_events & EV_WRITE)
	evep->evwrite = ev;

	return (0);
	}

	static int
	epoll_del(void arg, struct event ev)
	{
	struct epollop *epollop = arg;
	struct epoll_event epev = {0};
	struct evepoll *evep;
	int fd, events, op;
	int needwritedelete = 1, needreaddelete = 1;

	#ifndef STARBOARD
	if (ev->ev_events & EV_SIGNAL)
	return (evsignal_del(ev));
	#endif

	fd = ev->ev_fd;
	if (fd >= epollop->nfds)
	return (0);
	evep = &epollop->fds[fd];

	op = EPOLL_CTL_DEL;
	events = 0;

	if (ev->ev_events & EV_READ)
	events \|= EPOLLIN;
	if (ev->ev_events & EV_WRITE)
	events \|= EPOLLOUT;

	if ((events & (EPOLLIN\|EPOLLOUT)) != (EPOLLIN\|EPOLLOUT)) {
	if ((events & EPOLLIN) && evep->evwrite != NULL) {
	needwritedelete = 0;
	events = EPOLLOUT;
	op = EPOLL_CTL_MOD;
	} else if ((events & EPOLLOUT) && evep->evread != NULL) {
	needreaddelete = 0;
	events = EPOLLIN;
	op = EPOLL_CTL_MOD;
	}
	}

	epev.events = events;
	epev.data.fd = fd;

	if (needreaddelete)
	evep->evread = NULL;
	if (needwritedelete)
	evep->evwrite = NULL;

	#ifdef STARBOARD
	if (epoll_ctl_del(epollop->epfd, op, fd, &epev) == -1)
	#else
	if (epoll_ctl(epollop->epfd, op, fd, &epev) == -1)
	#endif
	return (-1);

	return (0);
	}

	static void
	epoll_dealloc(struct event_base base, void arg)
	{
	struct epollop *epollop = arg;

	#ifndef STARBOARD
	evsignal_dealloc(base);
	#endif
	if (epollop->fds)
	free(epollop->fds);
	if (epollop->events)
	free(epollop->events);
	if (epollop->epfd >= 0)
	close(epollop->epfd);

	memset(epollop, 0, sizeof(struct epollop));
	free(epollop);
	}