1 files changed, 346 insertions, 0 deletions
diff --git a/libs/libevent/docs/select.c b/libs/libevent/docs/select.c
new file mode 100644
index 0000000000..8ae53cc11e
--- /dev/null
+++ b/libs/libevent/docs/select.c
@@ -0,0 +1,346 @@
+/*	$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 */