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

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

ipc/chromium/src/third_party/libevent/select.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: select.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
 #ifdef _EVENT_HAVE_SYS_SELECT_H
 #include <sys/select.h>
 #endif
 #include <sys/queue.h>
 #include <signal.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 "event2/thread.h"
 #include "evthread-internal.h"
 #include "log-internal.h"
 #include "evmap-internal.h"
 #ifndef _EVENT_HAVE_FD_MASK
 /* This type is mandatory, but Android doesn't define it. */
 typedef unsigned long fd_mask;
 #endif
 #ifndef NFDBITS
 #define NFDBITS (sizeof(fd_mask)*8)
 #endif
 /* Divide positive x by y, rounding up. */
 #define DIV_ROUNDUP(x, y)   (((x)+((y)-1))/(y))
 /* How many bytes to allocate for N fds? */
 #define SELECT_ALLOC_SIZE(n) \
 	(DIV_ROUNDUP(n, NFDBITS) * sizeof(fd_mask))
 struct selectop {
 	int event_fds;		/* Highest fd in fd set */
 	int event_fdsz;
 	int resize_out_sets;
 	fd_set *event_readset_in;
 	fd_set *event_writeset_in;
 	fd_set *event_readset_out;
 	fd_set *event_writeset_out;
 };
 static void *select_init(struct event_base *);
 static int select_add(struct event_base *, int, short old, short events, void*);
 static int select_del(struct event_base *, int, short old, short events, void*);
 static int select_dispatch(struct event_base *, struct timeval *);
 static void select_dealloc(struct event_base *);
 const struct eventop selectops = {
 	"select",
 	select_init,
 	select_add,
 	select_del,
 	select_dispatch,
 	select_dealloc,
 , /* doesn't need reinit. */
 	EV_FEATURE_FDS,
 ,
 };
 static int select_resize(struct selectop *sop, int fdsz);
 static void select_free_selectop(struct selectop *sop);
 static void *
 select_init(struct event_base *base)
 {
 	struct selectop *sop;
 	if (!(sop = mm_calloc(1, sizeof(struct selectop))))
 		return (NULL);
 	if (select_resize(sop, SELECT_ALLOC_SIZE(32 + 1))) {
 		select_free_selectop(sop);
 		return (NULL);
 	}
 	evsig_init(base);
 	return (sop);
 }
 #ifdef CHECK_INVARIANTS
 static void
 check_selectop(struct selectop *sop)
 {
 	/* nothing to be done here */
 }
 #else
 #define check_selectop(sop) do { (void) sop; } while (0)
 #endif
 static int
 select_dispatch(struct event_base *base, struct timeval *tv)
 {
 	int res=0, i, j, nfds;
 	struct selectop *sop = base->evbase;
 	check_selectop(sop);
 	if (sop->resize_out_sets) {
 		fd_set *readset_out=NULL, *writeset_out=NULL;
 		size_t sz = sop->event_fdsz;
 		if (!(readset_out = mm_realloc(sop->event_readset_out, sz)))
 			return (-1);
 		sop->event_readset_out = readset_out;
 		if (!(writeset_out = mm_realloc(sop->event_writeset_out, sz))) {
 			/* We don't free readset_out here, since it was
 			 * already successfully reallocated. The next time
 			 * we call select_dispatch, the realloc will be a
 			 * no-op. */
 			return (-1);
 		}
 		sop->event_writeset_out = writeset_out;
 		sop->resize_out_sets = 0;
 	}
 	memcpy(sop->event_readset_out, sop->event_readset_in,
 	       sop->event_fdsz);
 	memcpy(sop->event_writeset_out, sop->event_writeset_in,
 	       sop->event_fdsz);
 	nfds = sop->event_fds+1;
 	EVBASE_RELEASE_LOCK(base, th_base_lock);
 	res = select(nfds, sop->event_readset_out,
 	    sop->event_writeset_out, NULL, tv);
 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
 	check_selectop(sop);
 	if (res == -1) {
 		if (errno != EINTR) {
 			event_warn("select");
 			return (-1);
 		}
 		return (0);
 	}
 	event_debug(("%s: select reports %d", __func__, res));
 	check_selectop(sop);
 	i = random() % nfds;
 	for (j = 0; j < nfds; ++j) {
 		if (++i >= nfds)
 			i = 0;
 		res = 0;
 		if (FD_ISSET(i, sop->event_readset_out))
 			res |= EV_READ;
 		if (FD_ISSET(i, sop->event_writeset_out))
 			res |= EV_WRITE;
 		if (res == 0)
 			continue;
 		evmap_io_active(base, i, res);
 	}
 	check_selectop(sop);
 	return (0);
 }
 static int
 select_resize(struct selectop *sop, int fdsz)
 {
 	fd_set *readset_in = NULL;
 	fd_set *writeset_in = NULL;
 	if (sop->event_readset_in)
 		check_selectop(sop);
 	if ((readset_in = mm_realloc(sop->event_readset_in, fdsz)) == NULL)
 		goto error;
 	sop->event_readset_in = readset_in;
 	if ((writeset_in = mm_realloc(sop->event_writeset_in, fdsz)) == NULL) {
 		/* Note that this will leave event_readset_in expanded.
 		 * That's okay; we wouldn't want to free it, since that would
 		 * change the semantics of select_resize from "expand the
 		 * readset_in and writeset_in, or return -1" to "expand the
 		 * *set_in members, or trash them and return -1."
 		 */
 		goto error;
 	}
 	sop->event_writeset_in = writeset_in;
 	sop->resize_out_sets = 1;
 	memset((char *)sop->event_readset_in + sop->event_fdsz, 0,
 	    fdsz - sop->event_fdsz);
 	memset((char *)sop->event_writeset_in + sop->event_fdsz, 0,
 	    fdsz - sop->event_fdsz);
 	sop->event_fdsz = fdsz;
 	check_selectop(sop);
 	return (0);
  error:
 	event_warn("malloc");
 	return (-1);
 }
 static int
 select_add(struct event_base *base, int fd, short old, short events, void *p)
 {
 	struct selectop *sop = base->evbase;
 	(void) p;
 	EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
 	check_selectop(sop);
 	/*
 	 * Keep track of the highest fd, so that we can calculate the size
 	 * of the fd_sets for select(2)
 	 */
 	if (sop->event_fds < fd) {
 		int fdsz = sop->event_fdsz;
 		if (fdsz < (int)sizeof(fd_mask))
 			fdsz = (int)sizeof(fd_mask);
 		/* In theory we should worry about overflow here.  In
 		 * reality, though, the highest fd on a unixy system will
 		 * not overflow here. XXXX */
 		while (fdsz < (int) SELECT_ALLOC_SIZE(fd + 1))
 			fdsz *= 2;
 		if (fdsz != sop->event_fdsz) {
 			if (select_resize(sop, fdsz)) {
 				check_selectop(sop);
 				return (-1);
 			}
 		}
 		sop->event_fds = fd;
 	}
 	if (events & EV_READ)
 		FD_SET(fd, sop->event_readset_in);
 	if (events & EV_WRITE)
 		FD_SET(fd, sop->event_writeset_in);
 	check_selectop(sop);
 	return (0);
 }
 /*
  * Nothing to be done here.
  */
 static int
 select_del(struct event_base *base, int fd, short old, short events, void *p)
 {
 	struct selectop *sop = base->evbase;
 	(void)p;
 	EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
 	check_selectop(sop);
 	if (sop->event_fds < fd) {
 		check_selectop(sop);
 		return (0);
 	}
 	if (events & EV_READ)
 		FD_CLR(fd, sop->event_readset_in);
 	if (events & EV_WRITE)
 		FD_CLR(fd, sop->event_writeset_in);
 	check_selectop(sop);
 	return (0);
 }
 static void
 select_free_selectop(struct selectop *sop)
 {
 	if (sop->event_readset_in)
 		mm_free(sop->event_readset_in);
 	if (sop->event_writeset_in)
 		mm_free(sop->event_writeset_in);
 	if (sop->event_readset_out)
 		mm_free(sop->event_readset_out);
 	if (sop->event_writeset_out)
 		mm_free(sop->event_writeset_out);
 	memset(sop, 0, sizeof(struct selectop));
 	mm_free(sop);
 }
 static void
 select_dealloc(struct event_base *base)
 {
 	evsig_dealloc(base);
 	select_free_selectop(base->evbase);
 }

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

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