From 4e5f73581c4e2587434dfccc281d504f4c4dfe56 Mon Sep 17 00:00:00 2001
From: "Andrey A. Chernov" <ache@FreeBSD.org>
Date: Wed, 2 Aug 1995 12:03:12 +0000
Subject: [PATCH] Better approximation for TIOCGETP (gtty) for non-standard
 speeds. Old variant returns 38400 for them, now it returns nearest matched
 rounded down, expect speeds in range 0 > speed < 50 rounded up to not produce
 hangup.

---
 sys/kern/tty_compat.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/sys/kern/tty_compat.c b/sys/kern/tty_compat.c
index 26ed1ec380f..b266b56859d 100644
--- a/sys/kern/tty_compat.c
+++ b/sys/kern/tty_compat.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tty_compat.c	8.1 (Berkeley) 6/10/93
- * $Id: tty_compat.c,v 1.14 1995/08/01 23:27:36 ache Exp $
+ * $Id: tty_compat.c,v 1.15 1995/08/02 06:55:35 ache Exp $
  */
 
 /*
@@ -80,9 +80,22 @@ static struct speedtab compatspeeds[] = {
 };
 static int compatspcodes[] = {
 	0, 50, 75, 110, 134, 150, 200, 300, 600, 1200,
-	1800, 2400, 4800, 9600, 19200, 38400, 57600, 115200,
+	1800, 2400, 4800, 9600, 19200, 38400, 57600, 115200
 };
 
+static
+int ttcompatspeedtab(speed, table)
+	int speed;
+	register struct speedtab *table;
+{
+	if (speed == 0)
+		return (0); /* hangup */
+	for ( ; table->sp_speed > 0; table++)
+		if (table->sp_speed <= speed) /* nearest one, rounded down */
+			return (table->sp_code);
+	return (1); /* 50, min and not hangup */
+}
+
 int ttsetcompat(tp, com, data, term)
 	register struct tty *tp;
 	int *com;
@@ -187,16 +200,12 @@ ttcompat(tp, com, data, flag)
 	case TIOCGETP: {
 		register struct sgttyb *sg = (struct sgttyb *)data;
 		register cc_t *cc = tp->t_cc;
-		register speed;
 
-		speed = ttspeedtab(tp->t_ospeed, compatspeeds);
-		sg->sg_ospeed = (speed == -1) ? MAX_SPEED : speed;
+		sg->sg_ospeed = ttcompatspeedtab(tp->t_ospeed, compatspeeds);
 		if (tp->t_ispeed == 0)
 			sg->sg_ispeed = sg->sg_ospeed;
-		else {
-			speed = ttspeedtab(tp->t_ispeed, compatspeeds);
-			sg->sg_ispeed = (speed == -1) ? MAX_SPEED : speed;
-		}
+		else
+			sg->sg_ispeed = ttcompatspeedtab(tp->t_ispeed, compatspeeds);
 		sg->sg_erase = cc[VERASE];
 		sg->sg_kill = cc[VKILL];
 		sg->sg_flags = tp->t_flags = ttcompatgetflags(tp);