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, 40 insertions, 45 deletions

diff --git a/sys/kern/tty_pty.c b/sys/kern/tty_pty.c
index 7cbb13a523a..6cb8615f724 100644
--- a/sys/kern/tty_pty.c
+++ b/sys/kern/tty_pty.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tty_pty.c,v 1.14 2003/07/22 01:03:12 mickey Exp $	*/
+/*	$OpenBSD: tty_pty.c,v 1.15 2003/09/23 16:51:12 millert Exp $	*/
 /*	$NetBSD: tty_pty.c,v 1.33.4.1 1996/06/02 09:08:11 mrg Exp $	*/
 
 /*
@@ -50,6 +50,7 @@
 #include <sys/signalvar.h>
 #include <sys/uio.h>
 #include <sys/conf.h>
+#include <sys/poll.h>
 
 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
 
@@ -233,7 +234,7 @@ ptswrite(dev, uio, flag)
 
 /*
  * Start output on pseudo-tty.
- * Wake up process selecting or sleeping for input from controlling tty.
+ * Wake up process polling or sleeping for input from controlling tty.
  */
 void
 ptsstart(tp)
@@ -501,58 +502,52 @@ block:
 }
 
 int
-ptcselect(dev, rw, p)
-	dev_t dev;
-	int rw;
-	struct proc *p;
+ptcpoll(dev_t dev, int events, struct proc *p)
 {
-	register struct pt_softc *pti = &pt_softc[minor(dev)];
-	register struct tty *tp = pti->pt_tty;
-	int s;
+	struct pt_softc *pti = &pt_softc[minor(dev)];
+	struct tty *tp = pti->pt_tty;
+	int revents = 0, s;
 
-	if ((tp->t_state&TS_CARR_ON) == 0)
-		return (1);
-	switch (rw) {
+	if (!ISSET(tp->t_state, TS_CARR_ON))
+		return (POLLHUP);
+
+	if (!ISSET(tp->t_state, TS_ISOPEN))
+		goto notopen;
 
-	case FREAD:
+	if (events & (POLLIN | POLLRDNORM)) {
 		/*
-		 * Need to block timeouts (ttrstart).
+		 * Need to protect access to t_outq
 		 */
 		s = spltty();
-		if ((tp->t_state&TS_ISOPEN) &&
-		     tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0) {
-			splx(s);
-			return (1);
-		}
+		if ((tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP)) ||
+		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
+		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))
+			revents |= events & (POLLIN | POLLRDNORM);
 		splx(s);
-		/* FALLTHROUGH */
-
-	case 0:					/* exceptional */
-		if ((tp->t_state&TS_ISOPEN) &&
-		    (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
-		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
-			return (1);
-		selrecord(p, &pti->pt_selr);
-		break;
-
-
-	case FWRITE:
-		if (tp->t_state&TS_ISOPEN) {
-			if (pti->pt_flags & PF_REMOTE) {
-			    if (tp->t_canq.c_cc == 0)
-				return (1);
-			} else {
-			    if (tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2)
-				    return (1);
-			    if (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON))
-				    return (1);
-			}
-		}
-		selrecord(p, &pti->pt_selw);
-		break;
+	}
+	if (events & (POLLOUT | POLLWRNORM)) {
+		if ((pti->pt_flags & PF_REMOTE) ?
+		     (tp->t_canq.c_cc == 0) :
+		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG - 2) ||
+		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON))))
+			revents |= events & (POLLOUT | POLLWRNORM);
+	}
+	if (events & (POLLPRI | POLLRDBAND)) {
+		/* If in packet or user control mode, check for data. */
+		if (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
+		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))
+			revents |= events & (POLLPRI | POLLRDBAND);
+	}
 
+	if (revents == 0) {
+notopen:
+		if (events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND))
+			selrecord(p, &pti->pt_selr);
+		if (events & (POLLOUT | POLLWRNORM))
+			selrecord(p, &pti->pt_selw);
 	}
-	return (0);
+
+	return (revents);
 }
 
 void