Repo created

TMessagesProj/jni/voip/webrtc/base/third_party/libevent/select.c

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+/*	$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.
+ */
+
+#include "config.h"
+
+#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);
+}