The Tor Browser: ipc/chromium/src/third_party/libevent/devpoll.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/devpoll.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/devpoll.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * Copyright 2000-2009 Niels Provos <provos@citi.umich.edu>
  * Copyright 2009-2012 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"
 #include <sys/types.h>
 #include <sys/resource.h>
 #ifdef _EVENT_HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif
 #include <sys/queue.h>
 #include <sys/devpoll.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 #include "event2/event.h"
 #include "event2/event_struct.h"
 #include "event2/thread.h"
 #include "event-internal.h"
 #include "evsignal-internal.h"
 #include "log-internal.h"
 #include "evmap-internal.h"
 #include "evthread-internal.h"
 struct devpollop {
 	struct pollfd *events;
 	int nevents;
 	int dpfd;
 	struct pollfd *changes;
 	int nchanges;
 };
 static void *devpoll_init(struct event_base *);
 static int devpoll_add(struct event_base *, int fd, short old, short events, void *);
 static int devpoll_del(struct event_base *, int fd, short old, short events, void *);
 static int devpoll_dispatch(struct event_base *, struct timeval *);
 static void devpoll_dealloc(struct event_base *);
 const struct eventop devpollops = {
 	"devpoll",
 	devpoll_init,
 	devpoll_add,
 	devpoll_del,
 	devpoll_dispatch,
 	devpoll_dealloc,
 , /* need reinit */
 	EV_FEATURE_FDS|EV_FEATURE_O1,
 
 };
 #define NEVENT	32000
 static int
 devpoll_commit(struct devpollop *devpollop)
 {
 	/*
 	 * Due to a bug in Solaris, we have to use pwrite with an offset of 0.
 	 * Write is limited to 2GB of data, until it will fail.
 	 */
 	if (pwrite(devpollop->dpfd, devpollop->changes,
 		sizeof(struct pollfd) * devpollop->nchanges, 0) == -1)
 		return (-1);
 	devpollop->nchanges = 0;
 	return (0);
 }
 static int
 devpoll_queue(struct devpollop *devpollop, int fd, int events) {
 	struct pollfd *pfd;
 	if (devpollop->nchanges >= devpollop->nevents) {
 		/*
 		 * Change buffer is full, must commit it to /dev/poll before
 		 * adding more
 		 */
 		if (devpoll_commit(devpollop) != 0)
 			return (-1);
 	}
 	pfd = &devpollop->changes[devpollop->nchanges++];
 	pfd->fd = fd;
 	pfd->events = events;
 	pfd->revents = 0;
 	return (0);
 }
 static void *
 devpoll_init(struct event_base *base)
 {
 	int dpfd, nfiles = NEVENT;
 	struct rlimit rl;
 	struct devpollop *devpollop;
 	if (!(devpollop = mm_calloc(1, sizeof(struct devpollop))))
 		return (NULL);
 	if (getrlimit(RLIMIT_NOFILE, &rl) == 0 &&
 	    rl.rlim_cur != RLIM_INFINITY)
 		nfiles = rl.rlim_cur;
 	/* Initialize the kernel queue */
 	if ((dpfd = evutil_open_closeonexec("/dev/poll", O_RDWR, 0)) == -1) {
 		event_warn("open: /dev/poll");
 		mm_free(devpollop);
 		return (NULL);
 	}
 	devpollop->dpfd = dpfd;
 	/* Initialize fields */
 	/* FIXME: allocating 'nfiles' worth of space here can be
 	 * expensive and unnecessary.  See how epoll.c does it instead. */
 	devpollop->events = mm_calloc(nfiles, sizeof(struct pollfd));
 	if (devpollop->events == NULL) {
 		mm_free(devpollop);
 		close(dpfd);
 		return (NULL);
 	}
 	devpollop->nevents = nfiles;
 	devpollop->changes = mm_calloc(nfiles, sizeof(struct pollfd));
 	if (devpollop->changes == NULL) {
 		mm_free(devpollop->events);
 		mm_free(devpollop);
 		close(dpfd);
 		return (NULL);
 	}
 	evsig_init(base);
 	return (devpollop);
 }
 static int
 devpoll_dispatch(struct event_base *base, struct timeval *tv)
 {
 	struct devpollop *devpollop = base->evbase;
 	struct pollfd *events = devpollop->events;
 	struct dvpoll dvp;
 	int i, res, timeout = -1;
 	if (devpollop->nchanges)
 		devpoll_commit(devpollop);
 	if (tv != NULL)
 		timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
 	dvp.dp_fds = devpollop->events;
 	dvp.dp_nfds = devpollop->nevents;
 	dvp.dp_timeout = timeout;
 	EVBASE_RELEASE_LOCK(base, th_base_lock);
 	res = ioctl(devpollop->dpfd, DP_POLL, &dvp);
 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
 	if (res == -1) {
 		if (errno != EINTR) {
 			event_warn("ioctl: DP_POLL");
 			return (-1);
 		}
 		return (0);
 	}
 	event_debug(("%s: devpoll_wait reports %d", __func__, res));
 	for (i = 0; i < res; i++) {
 		int which = 0;
 		int what = events[i].revents;
 		if (what & POLLHUP)
 			what |= POLLIN | POLLOUT;
 		else if (what & POLLERR)
 			what |= POLLIN | POLLOUT;
 		if (what & POLLIN)
 			which |= EV_READ;
 		if (what & POLLOUT)
 			which |= EV_WRITE;
 		if (!which)
 			continue;
 		/* XXX(niels): not sure if this works for devpoll */
 		evmap_io_active(base, events[i].fd, which);
 	}
 	return (0);
 }
 static int
 devpoll_add(struct event_base *base, int fd, short old, short events, void *p)
 {
 	struct devpollop *devpollop = base->evbase;
 	int res;
 	(void)p;
 	/*
 	 * It's not necessary to OR the existing read/write events that we
 	 * are currently interested in with the new event we are adding.
 	 * The /dev/poll driver ORs any new events with the existing events
 	 * that it has cached for the fd.
 	 */
 	res = 0;
 	if (events & EV_READ)
 		res |= POLLIN;
 	if (events & EV_WRITE)
 		res |= POLLOUT;
 	if (devpoll_queue(devpollop, fd, res) != 0)
 		return (-1);
 	return (0);
 }
 static int
 devpoll_del(struct event_base *base, int fd, short old, short events, void *p)
 {
 	struct devpollop *devpollop = base->evbase;
 	int res;
 	(void)p;
 	res = 0;
 	if (events & EV_READ)
 		res |= POLLIN;
 	if (events & EV_WRITE)
 		res |= POLLOUT;
 	/*
 	 * The only way to remove an fd from the /dev/poll monitored set is
 	 * to use POLLREMOVE by itself.  This removes ALL events for the fd
 	 * provided so if we care about two events and are only removing one
 	 * we must re-add the other event after POLLREMOVE.
 	 */
 	if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0)
 		return (-1);
 	if ((res & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) {
 		/*
 		 * We're not deleting all events, so we must resubmit the
 		 * event that we are still interested in if one exists.
 		 */
 		if ((res & POLLIN) && (old & EV_WRITE)) {
 			/* Deleting read, still care about write */
 			devpoll_queue(devpollop, fd, POLLOUT);
 		} else if ((res & POLLOUT) && (old & EV_READ)) {
 			/* Deleting write, still care about read */
 			devpoll_queue(devpollop, fd, POLLIN);
 		}
 	}
 	return (0);
 }
 static void
 devpoll_dealloc(struct event_base *base)
 {
 	struct devpollop *devpollop = base->evbase;
 	evsig_dealloc(base);
 	if (devpollop->events)
 		mm_free(devpollop->events);
 	if (devpollop->changes)
 		mm_free(devpollop->changes);
 	if (devpollop->dpfd >= 0)
 		close(devpollop->dpfd);
 	memset(devpollop, 0, sizeof(struct devpollop));
 	mm_free(devpollop);
 }

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ipc/chromium/src/third_party/libevent/devpoll.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/devpoll.c