Fix vt(4) detection in kbdcontrol and vidcontrol

As sc(4) and vt(4) coexist and are both enabled in GENERIC, the existence
of a vt(4) sysctl is not sufficient to determine that vt(4) is in use.

Reported by:	Trond Endrestøl

2 files changed, 10 insertions, 8 deletions

diff --git a/usr.sbin/kbdcontrol/kbdcontrol.c b/usr.sbin/kbdcontrol/kbdcontrol.c
index d38eda0..0f927ef 100644
--- a/usr.sbin/kbdcontrol/kbdcontrol.c
+++ b/usr.sbin/kbdcontrol/kbdcontrol.c
@@ -146,11 +146,12 @@ static void	usage(void) __dead2;
 static int
 is_vt4(void)
 {
+	char vty_name[4] = "";
+	size_t len = sizeof(vty_name);
 
-	if (sysctlbyname("kern.vt.deadtimer", NULL, NULL, NULL, 0) == 0)
-		return (1);
-
-	return (0);
+	if (sysctlbyname("kern.vty", vty_name, &len, NULL, 0) != 0)
+		return (0);
+	return (strcmp(vty_name, "vt") == 0);
 }
 
 static char *
diff --git a/usr.sbin/vidcontrol/vidcontrol.c b/usr.sbin/vidcontrol/vidcontrol.c
index 2096e2a..32e4de6 100644
--- a/usr.sbin/vidcontrol/vidcontrol.c
+++ b/usr.sbin/vidcontrol/vidcontrol.c
@@ -216,11 +216,12 @@ usage(void)
 static int
 is_vt4(void)
 {
+	char vty_name[4] = "";
+	size_t len = sizeof(vty_name);
 
-	if (sysctlbyname("kern.vt.deadtimer", NULL, NULL, NULL, 0) == 0)
-		return (1);
-
-	return (0);
+	if (sysctlbyname("kern.vty", vty_name, &len, NULL, 0) != 0)
+		return (0);
+	return (strcmp(vty_name, "vt") == 0);
 }
 
 /*