Look for the string "amazon" in a few different sysctl nodes. There doesn't

seem to be a single spot to check that works with both XenPVHVM and KVM
instances.

distrib/amd64/liveimage/emuimage/ec2_init

@@ -1,15 +1,22 @@
-# $NetBSD: ec2_init,v 1.1 2020/08/05 01:35:18 jmcneill Exp $
+# $NetBSD: ec2_init,v 1.2 2020/09/09 13:25:48 jmcneill Exp $
 
 is_ec2() {
-	dmi_vendor="$(/sbin/sysctl -qn machdep.dmi.system-vendor | tr '[A-Z]' '[a-z]')"
-	case "$dmi_vendor" in
-	amazon*)
-		printf YES
-		;;
-	*)
-		printf NO
-		;;
-	esac
+	val=NO
+	# Look for the string "amazon" in one of these sysctl nodes
+	for node in machdep.dmi.system-vendor \
+		    machdep.dmi.system-version \
+		    machdep.dmi.bios-version \
+		    machdep.xen.version ; do
+		if /sbin/sysctl -q $node; then
+			nodeval="$(/sbin/sysctl -n $node | tr '[A-Z]' '[a-z]')"
+			case "$nodeval" in
+			*amazon*)
+				val=YES
+				;;
+			esac
+		fi
+	done
+	printf $val
 }
 
 ec2_init=$(is_ec2)