Replace select backends with poll backends. selscan() and pollscan()

now call the poll backend.  With this change we implement greater
poll(2) functionality instead of emulating it via the select backend.
Adapted from NetBSD and including some changes from FreeBSD.
Tested by many, deraadt@ OK

1 files changed, 22 insertions, 21 deletions

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 924b686d74a..1a86d45a0d6 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tty.c,v 1.60 2003/08/23 19:21:15 deraadt Exp $	*/
+/*	$OpenBSD: tty.c,v 1.61 2003/09/23 16:51:12 millert Exp $	*/
 /*	$NetBSD: tty.c,v 1.68.4.2 1996/06/06 16:04:52 thorpej Exp $	*/
 
 /*-
@@ -56,6 +56,7 @@
 #include <sys/resourcevar.h>
 #include <sys/sysctl.h>
 #include <sys/pool.h>
+#include <sys/poll.h>
 
 #include <sys/namei.h>
 
@@ -1026,35 +1027,35 @@ ttioctl(tp, cmd, data, flag, p)
 }
 
 int
-ttselect(device, rw, p)
+ttpoll(device, events, p)
 	dev_t device;
-	int rw;
+	int events;
 	struct proc *p;
 {
-	register struct tty *tp;
-	int nread, s;
+	struct tty *tp;
+	int revents, s;
 
 	tp = (*cdevsw[major(device)].d_tty)(device);
 
+	revents = 0;
 	s = spltty();
-	switch (rw) {
-	case FREAD:
-		nread = ttnread(tp);
-		if (nread > 0 || (!ISSET(tp->t_cflag, CLOCAL) &&
-				  !ISSET(tp->t_state, TS_CARR_ON)))
-			goto win;
-		selrecord(p, &tp->t_rsel);
-		break;
-	case FWRITE:
-		if (tp->t_outq.c_cc <= tp->t_lowat) {
-win:			splx(s);
-			return (1);
-		}
-		selrecord(p, &tp->t_wsel);
-		break;
+	if (events & (POLLIN | POLLRDNORM)) {
+		if (ttnread(tp) > 0 || (!ISSET(tp->t_cflag, CLOCAL) &&
+		    !ISSET(tp->t_state, TS_CARR_ON)))
+			revents |= events & (POLLIN | POLLRDNORM);
+	}
+	if (events & (POLLOUT | POLLWRNORM)) {
+		if (tp->t_outq.c_cc <= tp->t_lowat)
+			revents |= events & (POLLOUT | POLLWRNORM);
+	}
+	if (revents == 0) {
+		if (events & (POLLIN | POLLRDNORM))
+			selrecord(p, &tp->t_rsel);
+		if (events & (POLLOUT | POLLWRNORM))
+			selrecord(p, &tp->t_wsel);
 	}
 	splx(s);
-	return (0);
+	return (revents);
 }
 
 struct filterops ttyread_filtops =