select.c - platform/external/libevent - Gitiles

 /*	$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 "evconfig-private.h"

 #ifdef EVENT__HAVE_SELECT

 #ifdef __APPLE__
 /* Apple wants us to define this if we might ever pass more than
  * FD_SETSIZE bits to select(). */
 #define _DARWIN_UNLIMITED_SELECT
 #endif

 #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,
 	0, /* doesn't need reinit. */
 	EV_FEATURE_FDS,
 	0,
 };

 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);

 	evutil_weakrand_seed_(&base->weakrand_seed, 0);

 	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 = evutil_weakrand_range_(&base->weakrand_seed, 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);
 }

 #endif /* EVENT__HAVE_SELECT */
	/* $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 "evconfig-private.h"

	#ifdef EVENT__HAVE_SELECT

	#ifdef __APPLE__
	/* Apple wants us to define this if we might ever pass more than
	* FD_SETSIZE bits to select(). */
	#define _DARWIN_UNLIMITED_SELECT
	#endif

	#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,
	0, /* doesn't need reinit. */
	EV_FEATURE_FDS,
	0,
	};

	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);

	evutil_weakrand_seed_(&base->weakrand_seed, 0);

	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 = evutil_weakrand_range_(&base->weakrand_seed, 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);
	}

	#endif /* EVENT__HAVE_SELECT */