eloop: Just use ppoll(2)

epoll and kqueue are really too heavy weight.
With privsep, we now favour more processes for BPF and per address sockets.
As such, the number of fds to monitor will always be quite small.

All modern OS now have ppoll(2) (NetBSD has pollts, which is the same)
which works perfectly for us.
If neither are present, the a wrapper around pselect(2) is provided,
which can be found on all POSIX systems.

This makes the code a lot smaller and easier to follow.
The reduced binary size and memory usage is a nice win here.

1 files changed, 26 insertions, 59 deletions

diff --git a/configure b/configure
index e82be878..b2532680 100755
--- a/configure
+++ b/configure
@@ -1211,65 +1211,42 @@ fi
 echo "#define	HAVE_REALLOCARRAY" >>$CONFIG_H
 
 if [ -z "$POLL" ]; then
-	printf "Testing for kqueue1 ... "
-	cat <<EOF >_kqueue.c
-#include <sys/types.h>
-#include <sys/event.h>
+	printf "Testing for ppoll ... "
+	cat <<EOF >_ppoll.c
+#include <poll.h>
+#include <stddef.h>
 int main(void) {
-	return kqueue1(0);
+	struct pollfd fds;
+	return ppoll(&fds, 1, NULL, NULL);
 }
 EOF
-	if $XCC _kqueue.c -o _kqueue 2>&3; then
-		POLL=kqueue1
- 		echo "yes"
- 	else
- 		echo "no"
- 	fi
-	rm -f _kqueue.c _kqueue
+	if $XCC _ppoll.c -o _ppoll 2>&3; then
+		POLL=ppoll
+		echo "#define	HAVE_PPOLL" >>$CONFIG_MK
+		echo "yes"
+	else
+		echo "no"
+	fi
+	rm -f _ppoll.c _ppoll
 fi
 if [ -z "$POLL" ]; then
-	printf "Testing for kqueue ... "
-	cat <<EOF >_kqueue.c
-#include <sys/types.h>
-#include <sys/event.h>
+	printf "Testing for pollts ... "
+	cat <<EOF >_pollts.c
+#include <poll.h>
+#include <stddef.h>
 int main(void) {
-	return kqueue();
+	struct pollfd fds;
+	return pollts(&fds, 1, NULL, NULL);
 }
 EOF
-	if $XCC _kqueue.c -o _kqueue 2>&3; then
-		POLL=kqueue
- 		echo "yes"
- 	else
- 		echo "no"
- 	fi
-	rm -f _kqueue.c _kqueue
-fi
-if [ -z "$POLL" ]; then
-	printf "Testing for epoll ... "
-	cat <<EOF >_epoll.c
-#ifdef __linux__
-#include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 37)
-#error kernel has buggy epoll_wait timeout
-#endif
-#endif
-
-#include <sys/epoll.h>
-#include <unistd.h>
-int main(void) {
-	epoll_create1(EPOLL_CLOEXEC);
-	epoll_pwait(-1, NULL, 0, 0, NULL);
-	return 0;
-}
-EOF
-	if $XCC _epoll.c -o _epoll 2>&3; then
-		POLL=epoll
-		echo "#define	HAVE_EPOLL" >>$CONFIG_MK
+	if $XCC _pollts.c -o _pollts 2>&3; then
+		POLL=pollts
+		echo "#define	HAVE_PPOLL" >>$CONFIG_MK
 		echo "yes"
 	else
 		echo "no"
 	fi
-	rm -f _epoll.c _epoll
+	rm -f _pollts.c _pollts
 fi
 if [ -z "$POLL" ]; then
 	printf "Testing for pselect ... "
@@ -1290,22 +1267,12 @@ EOF
 	rm -f _pselect.c _pselect
 fi
 case "$POLL" in
-kqueue1)
-	echo "#define	HAVE_KQUEUE" >>$CONFIG_H
-	echo "#define	HAVE_KQUEUE1" >>$CONFIG_H
-	;;
-kqueue)
-	echo "#define	HAVE_KQUEUE" >>$CONFIG_H
-	;;
-epoll)
-	echo "#define	HAVE_EPOLL" >>$CONFIG_H
+ppoll)
+	echo "#define	HAVE_PPOLL" >>$CONFIG_H
 	;;
 pollts)
 	echo "#define	HAVE_POLLTS" >>$CONFIG_H
 	;;
-ppoll)
-	echo "#define	HAVE_PPOLL" >>$CONFIG_H
-	;;
 pselect)
 	echo "#define	HAVE_PSELECT" >>$CONFIG_H
 	;;