From 3f6cf39fb2b3f7089f47ed109ab42e16bae8a46a Mon Sep 17 00:00:00 2001
From: Xin LI <delphij@FreeBSD.org>
Date: Mon, 27 Apr 2015 20:21:56 +0000
Subject: [PATCH] Generate new UUID if system UUID is known bad or malformed
 and add a two seconds sleep if we found the system UUID be invalid.

Obtained from:	FreeNAS
MFC after:	2 weeks
---
 etc/rc.d/hostid | 70 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 59 insertions(+), 11 deletions(-)

diff --git a/etc/rc.d/hostid b/etc/rc.d/hostid
index c4545bd7916a..281b2417c9ea 100755
--- a/etc/rc.d/hostid
+++ b/etc/rc.d/hostid
@@ -1,6 +1,7 @@
 #!/bin/sh
 #
 # Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+# Copyright (c) 2015 Xin LI <delphij@FreeBSD.org>
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -55,23 +56,66 @@ hostid_set()
 	${SYSCTL} kern.hostid=${id} >/dev/null
 }
 
+valid_hostid()
+{
+	uuid=$1
+
+	x="[0-9a-f]"
+	y=$x$x$x$x
+
+	# Check against a blacklist before
+	# accepting the UUID.
+	case "${uuid}" in
+	00000000-0000-0000-0000-000000000000)
+		;;
+	00020003-0004-0005-0006-000700080009)
+		;;
+	03000200-0400-0500-0006-000700080009)
+		;;
+	07090201-0103-0301-0807-060504030201)
+		;;
+	11111111-1111-1111-1111-111111111111)
+		;;
+	11111111-2222-3333-4444-555555555555)
+		;;
+	4c4c4544-0000-2010-8020-80c04f202020)
+		;;
+	58585858-5858-5858-5858-585858585858)
+		;;
+	890e2d14-cacd-45d1-ae66-bc80e8bfeb0f)
+		;;
+	8e275844-178f-44a8-aceb-a7d7e5178c63)
+		;;
+	dc698397-fa54-4cf2-82c8-b1b5307a6a7f)
+		;;
+	fefefefe-fefe-fefe-fefe-fefefefefefe)
+		;;
+	*-ffff-ffff-ffff-ffffffffffff)
+		;;
+	$y$y-$y-$y-$y-$y$y$y)
+		return 0
+		;;
+	esac
+
+	return 1
+}
+
 hostid_hardware()
 {
 	uuid=`kenv -q smbios.system.uuid`
-	x="[0-9a-f]"
-	y=$x$x$x$x
-	case "${uuid}" in
-	$y$y-$y-$y-$y-$y$y$y)
+
+	if valid_hostid $uuid; then
 		echo "${uuid}"
-		;;
-	esac
+	fi
 }
 
 hostid_generate()
 {
 	# First look for UUID in hardware.
 	uuid=`hostid_hardware`
-	if [ -z ${uuid} ]; then
+	if [ -z "${uuid}" ]; then
+		warn "hostid: unable to figure out a UUID from DMI data, generating a new one"
+		sleep 2
 		# If not found, fall back to software-generated UUID.
 		uuid=`uuidgen`
 	fi
@@ -92,11 +136,15 @@ hostid_start()
 {
 	# If ${hostid_file} already exists, we take UUID from there.
 	if [ -r ${hostid_file} ]; then
-		hostid_set `cat ${hostid_file}`
-	else
-		# No hostid file, generate UUID.
-		hostid_generate
+		read saved_hostid < ${hostid_file}
+		if valid_hostid ${saved_hostid}; then
+			hostid_set `cat ${hostid_file}`
+			exit 0
+		fi
 	fi
+
+	# No hostid file, generate UUID.
+	hostid_generate
 }
 
 load_rc_config $name