Implement an optional TIMEOUT value while entering the boot parameter

string.  This avoids indefinite hangs e.g. when used on a noisy serial
console.  It's not turned on by default.

sys/i386/boot/biosboot/Makefile

@@ -1,4 +1,4 @@
-#	$Id: Makefile,v 1.34 1996/01/05 19:28:55 ache Exp $
+#	$Id: Makefile,v 1.35 1996/01/06 23:37:10 joerg Exp $
 #
 
 PROG=	boot
@@ -9,7 +9,8 @@ SRCS+=  probe_keyboard.c io.c disk.c sys.c
 BINDIR=		/usr/mdec
 BINMODE=	444
 CFLAGS=         -O2 \
-		-DDO_BAD144 -DBOOTWAIT=${BOOTWAIT} -DCOMCONSOLE=0x3F8
+		-DDO_BAD144 -DBOOTWAIT=${BOOTWAIT} -DTIMEOUT=${TIMEOUT}
+CFLAGS+=	-DCOMCONSOLE=0x3F8
 CFLAGS+=	-DBOOTSEG=${BOOTSEG} -DBOOTSTACK=${BOOTSTACK}
 CFLAGS+=	-I${.CURDIR} -I${.CURDIR}/../..
 
@@ -33,8 +34,10 @@ NOSHARED=	YES
 NOMAN=
 STRIP=
 
-# tunable timeout parameter, waiting for keypress, calibrated in mS
+# tunable timeout parameter, waiting for keypress, calibrated in ms
 BOOTWAIT?=	5000
+# tunable timeout during string input, calibrated in ms
+#TIMEOUT?=	30000
 
 # Location that boot2 is loaded at
 BOOTSEG=	0x1000

sys/i386/boot/biosboot/io.c

@@ -24,7 +24,7 @@
  * the rights to redistribute these changes.
  *
  *	from: Mach, Revision 2.2  92/04/04  11:35:57  rpd
- *	$Id: io.c,v 1.14 1995/05/30 07:58:33 rgrimes Exp $
+ *	$Id: io.c,v 1.15 1995/06/25 14:02:53 joerg Exp $
  */
 
 #include "boot.h"
@@ -176,8 +176,12 @@ int
 gets(char *buf)
 {
 	int	i;
+#if TIMEOUT+0 > 0
+	int	j;
+#endif
 	char *ptr=buf;
 
+#if TIMEOUT+0 == 0
 #if BOOTWAIT
 	for (i = BOOTWAIT; i>0; delay1ms(),i--)
 #endif
@@ -194,6 +198,28 @@ gets(char *buf)
 				      default:
 					ptr++;
 				}
+#else /* TIMEOUT */
+#if BOOTWAIT == 0
+# error "TIMEOUT without BOOTWAIT"
+#endif
+	for (i = BOOTWAIT; i>0; delay1ms(),i--)
+		if ((loadflags & RB_SERIAL) ? serial_ischar() : ischar())
+			for (j = TIMEOUT; j>0; delay1ms(),j--)
+				if ((loadflags & RB_SERIAL) ?
+				    serial_ischar() : ischar())
+					switch(*ptr = getchar(ptr - buf) &
+					       0xff) {
+					       case '\n':
+					       case '\r':
+						       *ptr = '\0';
+						       return 1;
+					       case '\b':
+						       if (ptr > buf) ptr--;
+						       continue;
+					       default:
+						       ptr++;
+					}
+#endif /* !TIMEOUT */
 	return 0;
 }