Evaluate running userland/kernel version in daily

periodic(8) run, taken from uname(1) '-U' and '-K'
flags.

Reviewed by:		allanjude, dvl
Differential Revision:	https://reviews.freebsd.org/D1541
MFC after:		1 week
Sponsored by:		The FreeBSD Foundation

etc/defaults/periodic.conf

@@ -140,6 +140,10 @@ daily_status_ntpd_enable="NO"				# Check NTP status
 daily_queuerun_enable="YES"				# Run mail queue
 daily_submit_queuerun="YES"				# Also submit queue
 
+# 510.status-world-kernel
+daily_status_world_kernel="YES"				# Check the running
+							# userland/kernel version
+
 # 800.scrub-zfs
 daily_scrub_zfs_enable="NO"
 daily_scrub_zfs_pools=""			# empty string selects all pools

etc/periodic/daily/510.status-world-kernel

@@ -0,0 +1,36 @@
+#!/bin/sh
+#
+# $FreeBSD$
+#
+# Check that the running userland and kernel versions are in sync.
+
+# If there is a global system configuration file, suck it in.
+#
+if [ -r /etc/defaults/periodic.conf ]
+then
+    . /etc/defaults/periodic.conf
+    source_periodic_confs
+fi
+
+case "$daily_status_world_kernel" in
+    [Yy][Ee][Ss])
+	rc=0
+	_U=$(/usr/bin/uname -U 2>/dev/null)
+	_K=$(/usr/bin/uname -K 2>/dev/null)
+	[ -z "${_U}" -o -z "${_K}" ] && exit 0
+	echo ""
+	echo "Checking userland and kernel versions:"
+	if [ "${_U}" != "${_K}" ]; then
+	    echo "Userland and kernel are not in sync"
+	    echo "Userland version: ${_U}"
+	    echo "Kernel version: ${_K}"
+	    rc=1
+	else
+	    echo "Userland and kernel are in sync."
+	fi
+	;;
+
+    *)  rc=0;;
+esac
+
+exit $rc

etc/periodic/daily/Makefile

@@ -16,6 +16,7 @@ FILES=	100.clean-disks \
 	409.status-gconcat \
 	420.status-network \
 	450.status-security \
+	510.status-world-kernel \
 	999.local
 
 # NB: keep these sorted by MK_* knobs

share/man/man5/periodic.conf.5

@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 25, 2013
+.Dd January 15, 2015
 .Dt PERIODIC.CONF 5
 .Os
 .Sh NAME
@@ -498,6 +498,11 @@ for yesterday's mail rejects.
 Set to
 .Dq Li YES
 if you want to enable NTP status check.
+.It Va daily_status_world_kernel
+.Pq Vt bool
+Set to
+.Dq Li YES
+to check the running userland and kernel are in sync.
 .It Va daily_queuerun_enable
 .Pq Vt bool
 Set to