blob: 3f73331317749bee6f161fc3d7cda4cd9b36dc7c [file] [log] [blame]
/* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
/*
* Copyright 2000-2002 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 <sys/types.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <sys/_libevent_time.h>
#endif
#ifdef 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>
#ifdef CHECK_INVARIANTS
#include <assert.h>
#endif
#include "event.h"
#include "evutil.h"
#include "event-internal.h"
#include "evsignal.h"
#include "log.h"
#ifndef howmany
#define howmany(x, y) (((x)+((y)-1))/(y))
#endif
#ifndef _EVENT_HAVE_FD_MASK
/* This type is mandatory, but Android doesn't define it. */
#undef NFDBITS
#define NFDBITS (sizeof(long)*8)
typedef unsigned long fd_mask;
#endif
struct selectop {
int event_fds; /* Highest fd in fd set */
int event_fdsz;
fd_set *event_readset_in;
fd_set *event_writeset_in;
fd_set *event_readset_out;
fd_set *event_writeset_out;
struct event **event_r_by_fd;
struct event **event_w_by_fd;
};
static void *select_init (struct event_base *);
static int select_add (void *, struct event *);
static int select_del (void *, struct event *);
static int select_dispatch (struct event_base *, void *, struct timeval *);
static void select_dealloc (struct event_base *, void *);
const struct eventop selectops = {
"select",
select_init,
select_add,
select_del,
select_dispatch,
select_dealloc,
0
};
static int select_resize(struct selectop *sop, int fdsz);
static void *
select_init(struct event_base *base)
{
struct selectop *sop;
/* Disable select when this environment variable is set */
if (evutil_getenv("EVENT_NOSELECT"))
return (NULL);
if (!(sop = calloc(1, sizeof(struct selectop))))
return (NULL);
select_resize(sop, howmany(32 + 1, NFDBITS)*sizeof(fd_mask));
evsignal_init(base);
return (sop);
}
#ifdef CHECK_INVARIANTS
static void
check_selectop(struct selectop *sop)
{
int i;
for (i = 0; i <= sop->event_fds; ++i) {
if (FD_ISSET(i, sop->event_readset_in)) {
assert(sop->event_r_by_fd[i]);
assert(sop->event_r_by_fd[i]->ev_events & EV_READ);
assert(sop->event_r_by_fd[i]->ev_fd == i);
} else {
assert(! sop->event_r_by_fd[i]);
}
if (FD_ISSET(i, sop->event_writeset_in)) {
assert(sop->event_w_by_fd[i]);
assert(sop->event_w_by_fd[i]->ev_events & EV_WRITE);
assert(sop->event_w_by_fd[i]->ev_fd == i);
} else {
assert(! sop->event_w_by_fd[i]);
}
}
}
#else
#define check_selectop(sop) do { (void) sop; } while (0)
#endif
static int
select_dispatch(struct event_base *base, void *arg, struct timeval *tv)
{
int res, i, j;
struct selectop *sop = arg;
check_selectop(sop);
memcpy(sop->event_readset_out, sop->event_readset_in,
sop->event_fdsz);
memcpy(sop->event_writeset_out, sop->event_writeset_in,
sop->event_fdsz);
res = select(sop->event_fds + 1, sop->event_readset_out,
sop->event_writeset_out, NULL, tv);
check_selectop(sop);
if (res == -1) {
if (errno != EINTR) {
event_warn("select");
return (-1);
}
evsignal_process(base);
return (0);
} else if (base->sig.evsignal_caught) {
evsignal_process(base);
}
event_debug(("%s: select reports %d", __func__, res));
check_selectop(sop);
i = random() % (sop->event_fds+1);
for (j = 0; j <= sop->event_fds; ++j) {
struct event *r_ev = NULL, *w_ev = NULL;
if (++i >= sop->event_fds+1)
i = 0;
res = 0;
if (FD_ISSET(i, sop->event_readset_out)) {
r_ev = sop->event_r_by_fd[i];
res |= EV_READ;
}
if (FD_ISSET(i, sop->event_writeset_out)) {
w_ev = sop->event_w_by_fd[i];
res |= EV_WRITE;
}
if (r_ev && (res & r_ev->ev_events)) {
event_active(r_ev, res & r_ev->ev_events, 1);
}
if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
event_active(w_ev, res & w_ev->ev_events, 1);
}
}
check_selectop(sop);
return (0);
}
static int
select_resize(struct selectop *sop, int fdsz)
{
int n_events, n_events_old;
fd_set *readset_in = NULL;
fd_set *writeset_in = NULL;
fd_set *readset_out = NULL;
fd_set *writeset_out = NULL;
struct event **r_by_fd = NULL;
struct event **w_by_fd = NULL;
n_events = (fdsz/sizeof(fd_mask)) * NFDBITS;
n_events_old = (sop->event_fdsz/sizeof(fd_mask)) * NFDBITS;
if (sop->event_readset_in)
check_selectop(sop);
if ((readset_in = realloc(sop->event_readset_in, fdsz)) == NULL)
goto error;
sop->event_readset_in = readset_in;
if ((readset_out = realloc(sop->event_readset_out, fdsz)) == NULL)
goto error;
sop->event_readset_out = readset_out;
if ((writeset_in = realloc(sop->event_writeset_in, fdsz)) == NULL)
goto error;
sop->event_writeset_in = writeset_in;
if ((writeset_out = realloc(sop->event_writeset_out, fdsz)) == NULL)
goto error;
sop->event_writeset_out = writeset_out;
if ((r_by_fd = realloc(sop->event_r_by_fd,
n_events*sizeof(struct event*))) == NULL)
goto error;
sop->event_r_by_fd = r_by_fd;
if ((w_by_fd = realloc(sop->event_w_by_fd,
n_events * sizeof(struct event*))) == NULL)
goto error;
sop->event_w_by_fd = w_by_fd;
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);
memset(sop->event_r_by_fd + n_events_old, 0,
(n_events-n_events_old) * sizeof(struct event*));
memset(sop->event_w_by_fd + n_events_old, 0,
(n_events-n_events_old) * sizeof(struct event*));
sop->event_fdsz = fdsz;
check_selectop(sop);
return (0);
error:
event_warn("malloc");
return (-1);
}
static int
select_add(void *arg, struct event *ev)
{
struct selectop *sop = arg;
if (ev->ev_events & EV_SIGNAL)
return (evsignal_add(ev));
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 < ev->ev_fd) {
int fdsz = sop->event_fdsz;
if (fdsz < sizeof(fd_mask))
fdsz = sizeof(fd_mask);
while (fdsz <
(howmany(ev->ev_fd + 1, NFDBITS) * sizeof(fd_mask)))
fdsz *= 2;
if (fdsz != sop->event_fdsz) {
if (select_resize(sop, fdsz)) {
check_selectop(sop);
return (-1);
}
}
sop->event_fds = ev->ev_fd;
}
if (ev->ev_events & EV_READ) {
FD_SET(ev->ev_fd, sop->event_readset_in);
sop->event_r_by_fd[ev->ev_fd] = ev;
}
if (ev->ev_events & EV_WRITE) {
FD_SET(ev->ev_fd, sop->event_writeset_in);
sop->event_w_by_fd[ev->ev_fd] = ev;
}
check_selectop(sop);
return (0);
}
/*
* Nothing to be done here.
*/
static int
select_del(void *arg, struct event *ev)
{
struct selectop *sop = arg;
check_selectop(sop);
if (ev->ev_events & EV_SIGNAL)
return (evsignal_del(ev));
if (sop->event_fds < ev->ev_fd) {
check_selectop(sop);
return (0);
}
if (ev->ev_events & EV_READ) {
FD_CLR(ev->ev_fd, sop->event_readset_in);
sop->event_r_by_fd[ev->ev_fd] = NULL;
}
if (ev->ev_events & EV_WRITE) {
FD_CLR(ev->ev_fd, sop->event_writeset_in);
sop->event_w_by_fd[ev->ev_fd] = NULL;
}
check_selectop(sop);
return (0);
}
static void
select_dealloc(struct event_base *base, void *arg)
{
struct selectop *sop = arg;
evsignal_dealloc(base);
if (sop->event_readset_in)
free(sop->event_readset_in);
if (sop->event_writeset_in)
free(sop->event_writeset_in);
if (sop->event_readset_out)
free(sop->event_readset_out);
if (sop->event_writeset_out)
free(sop->event_writeset_out);
if (sop->event_r_by_fd)
free(sop->event_r_by_fd);
if (sop->event_w_by_fd)
free(sop->event_w_by_fd);
memset(sop, 0, sizeof(struct selectop));
free(sop);
}