Index: include/ttyent.h
===================================================================
--- include/ttyent.h	(revision 260331)
+++ include/ttyent.h	(working copy)
@@ -37,6 +37,7 @@
 
 #define	_TTYS_OFF	"off"
 #define	_TTYS_ON	"on"
+#define	_TTYS_AUTO	"auto"
 #define	_TTYS_SECURE	"secure"
 #define	_TTYS_INSECURE	"insecure"
 #define	_TTYS_WINDOW	"window"
Index: lib/libc/gen/getttyent.c
===================================================================
--- lib/libc/gen/getttyent.c	(revision 260331)
+++ lib/libc/gen/getttyent.c	(working copy)
@@ -39,6 +39,9 @@
 #include <ctype.h>
 #include <string.h>
 
+#include <sys/types.h>
+#include <sys/sysctl.h>
+
 static char zapchar;
 static FILE *tf;
 static size_t lbsize;
@@ -64,6 +67,32 @@
 	return (t);
 }
 
+static int
+auto_tty_status(const char *ty_name)
+{
+	size_t len;
+	char *buf, *cons, *nextcons;
+
+	/* Check if this is an enabled kernel console line */
+	buf = NULL;
+	if (sysctlbyname("kern.console", NULL, &len, NULL, 0) == -1)
+		return (0); /* Errors mean don't enable */
+	buf = malloc(len);
+	if (sysctlbyname("kern.console", buf, &len, NULL, 0) == -1)
+		return (0);
+
+	if ((cons = strchr(buf, '/')) == NULL)
+		return (0);
+	*cons = '\0';
+	nextcons = buf;
+	while ((cons = strsep(&nextcons, ",")) != NULL && strlen(cons) != 0) {
+		if (strcmp(cons, ty_name) == 0)
+			return (TTY_ON);
+	}
+
+	return (0);
+}
+
 struct ttyent *
 getttyent(void)
 {
@@ -126,6 +155,8 @@
 			tty.ty_status &= ~TTY_ON;
 		else if (scmp(_TTYS_ON))
 			tty.ty_status |= TTY_ON;
+		else if (scmp(_TTYS_AUTO))
+			tty.ty_status |= auto_tty_status(tty.ty_name);
 		else if (scmp(_TTYS_SECURE))
 			tty.ty_status |= TTY_SECURE;
 		else if (scmp(_TTYS_INSECURE))
Index: libexec/getty/ttys.5
===================================================================
--- libexec/getty/ttys.5	(revision 260331)
+++ libexec/getty/ttys.5	(working copy)
@@ -102,8 +102,11 @@
 .Pp
 As flag values, the strings ``on'' and ``off'' specify that
 .Xr init 8
-should (should not) execute the command given in the second field,
-while ``secure'' (if ``on'' is also specified) allows users with a
+should (should not) execute the command given in the second field.
+``auto'' will cause this line to be enabled if and only if it is
+an active kernel console device (it is equivalent to ``on'' in this
+case).
+The flag ``secure'' (if ``on'' is also specified) allows users with a
 uid of 0 to login on
 this line.
 The flag ``dialin'' indicates that a tty entry describes a dialin