Prevent periodic/etc/weekly/340.noid from descending into root directories

of jails. Jails have their own user/group databases and this script
can produce multiple false warnings, not to mention significant extra
load in case of large jailed subtrees. Leave this check for jailed
invocations of the same script.

MFC after:	1 month

usr.sbin/periodic/etc/weekly/340.noid

@@ -16,8 +16,26 @@ case "$weekly_noid_enable" in
 	echo ""
 	echo "Check for files with an unknown user or group:"
 
+	# Host should not test jailed subtrees as jails have their own
+	# databases of users and groups. Leave them for jailed invocations
+	# of this script.
+
+	exclude=''
+	if [ $(sysctl -n security.jail.jailed) = 0 ]; then
+	    sep=:
+	    OIFS="$IFS"
+	    IFS="$sep"
+	    for param in $(jail -f "`syscrc jail_conf`" -e "$sep")
+	    do
+		case "$param" in
+		    path=*) exclude="$exclude -path ${param#path=} -prune -or"
+		esac
+	    done
+	    IFS="$OIFS"
+	fi
+
 	rc=$(find -H ${weekly_noid_dirs:-/} \
-	    \( ! -fstype local -prune -or -name \* \) -and \
+	    \( $exclude ! -fstype local -prune -or -name \* \) -and \
 	    \( -nogroup -o -nouser \) -print | sed 's/^/  /' |
 	    tee /dev/stderr | wc -l)
 	[ $rc -gt 1 ] && rc=1