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

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

ipc/chromium/src/third_party/libevent/poll.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.

 /*	$OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $	*/
 /*
  * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
  * 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 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>
 #ifdef _EVENT_HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif
 #include <sys/queue.h>
 #include <poll.h>
 #include <signal.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
 #include "event-internal.h"
 #include "evsignal-internal.h"
 #include "log-internal.h"
 #include "evmap-internal.h"
 #include "event2/thread.h"
 #include "evthread-internal.h"
 struct pollidx {
 	int idxplus1;
 };
 struct pollop {
 	int event_count;		/* Highest number alloc */
 	int nfds;			/* Highest number used */
 	int realloc_copy;		/* True iff we must realloc
 					 * event_set_copy */
 	struct pollfd *event_set;
 	struct pollfd *event_set_copy;
 };
 static void *poll_init(struct event_base *);
 static int poll_add(struct event_base *, int, short old, short events, void *_idx);
 static int poll_del(struct event_base *, int, short old, short events, void *_idx);
 static int poll_dispatch(struct event_base *, struct timeval *);
 static void poll_dealloc(struct event_base *);
 const struct eventop pollops = {
 	"poll",
 	poll_init,
 	poll_add,
 	poll_del,
 	poll_dispatch,
 	poll_dealloc,
 , /* doesn't need_reinit */
 	EV_FEATURE_FDS,
 	sizeof(struct pollidx),
 };
 static void *
 poll_init(struct event_base *base)
 {
 	struct pollop *pollop;
 	if (!(pollop = mm_calloc(1, sizeof(struct pollop))))
 		return (NULL);
 	evsig_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;
 		EVUTIL_ASSERT(pop->event_set[idx].fd == i);
 	}
 	for (i = 0; i < pop->nfds; ++i) {
 		struct pollfd *pfd = &pop->event_set[i];
 		EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1);
 	}
 }
 #else
 #define poll_check_ok(pop)
 #endif
 static int
 poll_dispatch(struct event_base *base, struct timeval *tv)
 {
 	int res, i, j, nfds;
 	long msec = -1;
 	struct pollop *pop = base->evbase;
 	struct pollfd *event_set;
 	poll_check_ok(pop);
 	nfds = pop->nfds;
 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
 	if (base->th_base_lock) {
 		/* If we're using this backend in a multithreaded setting,
 		 * then we need to work on a copy of event_set, so that we can
 		 * let other threads modify the main event_set while we're
 		 * polling. If we're not multithreaded, then we'll skip the
 		 * copy step here to save memory and time. */
 		if (pop->realloc_copy) {
 			struct pollfd *tmp = mm_realloc(pop->event_set_copy,
 			    pop->event_count * sizeof(struct pollfd));
 			if (tmp == NULL) {
 				event_warn("realloc");
 				return -1;
 			}
 			pop->event_set_copy = tmp;
 			pop->realloc_copy = 0;
 		}
 		memcpy(pop->event_set_copy, pop->event_set,
 		    sizeof(struct pollfd)*nfds);
 		event_set = pop->event_set_copy;
 	} else {
 		event_set = pop->event_set;
 	}
 #else
 	event_set = pop->event_set;
 #endif
 	if (tv != NULL) {
 		msec = evutil_tv_to_msec(tv);
 		if (msec < 0 || msec > INT_MAX)
 			msec = INT_MAX;
 	}
 	EVBASE_RELEASE_LOCK(base, th_base_lock);
 	res = poll(event_set, nfds, msec);
 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
 	if (res == -1) {
 		if (errno != EINTR) {
 			event_warn("poll");
 			return (-1);
 		}
 		return (0);
 	}
 	event_debug(("%s: poll reports %d", __func__, res));
 	if (res == 0 || nfds == 0)
 		return (0);
 	i = random() % nfds;
 	for (j = 0; j < nfds; j++) {
 		int what;
 		if (++i == nfds)
 			i = 0;
 		what = 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;
 		if (what & POLLOUT)
 			res |= EV_WRITE;
 		if (res == 0)
 			continue;
 		evmap_io_active(base, event_set[i].fd, res);
 	}
 	return (0);
 }
 static int
 poll_add(struct event_base *base, int fd, short old, short events, void *_idx)
 {
 	struct pollop *pop = base->evbase;
 	struct pollfd *pfd = NULL;
 	struct pollidx *idx = _idx;
 	int i;
 	EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
 	if (!(events & (EV_READ|EV_WRITE)))
 		return (0);
 	poll_check_ok(pop);
 	if (pop->nfds + 1 >= pop->event_count) {
 		struct pollfd *tmp_event_set;
 		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 = mm_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;
 		pop->event_count = tmp_event_count;
 		pop->realloc_copy = 1;
 	}
 	i = idx->idxplus1 - 1;
 	if (i >= 0) {
 		pfd = &pop->event_set[i];
 	} else {
 		i = pop->nfds++;
 		pfd = &pop->event_set[i];
 		pfd->events = 0;
 		pfd->fd = fd;
 		idx->idxplus1 = i + 1;
 	}
 	pfd->revents = 0;
 	if (events & EV_WRITE)
 		pfd->events |= POLLOUT;
 	if (events & EV_READ)
 		pfd->events |= POLLIN;
 	poll_check_ok(pop);
 	return (0);
 }
 /*
  * Nothing to be done here.
  */
 static int
 poll_del(struct event_base *base, int fd, short old, short events, void *_idx)
 {
 	struct pollop *pop = base->evbase;
 	struct pollfd *pfd = NULL;
 	struct pollidx *idx = _idx;
 	int i;
 	EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
 	if (!(events & (EV_READ|EV_WRITE)))
 		return (0);
 	poll_check_ok(pop);
 	i = idx->idxplus1 - 1;
 	if (i < 0)
 		return (-1);
 	/* Do we still want to read or write? */
 	pfd = &pop->event_set[i];
 	if (events & EV_READ)
 		pfd->events &= ~POLLIN;
 	if (events & EV_WRITE)
 		pfd->events &= ~POLLOUT;
 	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. */
 	idx->idxplus1 = 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));
 		idx = evmap_io_get_fdinfo(&base->io, pop->event_set[i].fd);
 		EVUTIL_ASSERT(idx);
 		EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1);
 		idx->idxplus1 = i + 1;
 	}
 	poll_check_ok(pop);
 	return (0);
 }
 static void
 poll_dealloc(struct event_base *base)
 {
 	struct pollop *pop = base->evbase;
 	evsig_dealloc(base);
 	if (pop->event_set)
 		mm_free(pop->event_set);
 	if (pop->event_set_copy)
 		mm_free(pop->event_set_copy);
 	memset(pop, 0, sizeof(struct pollop));
 	mm_free(pop);
 }

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

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