The rc system aggressively caches the contents of /etc/rc.conf in order to

improve boot performance; this produces arguably astonishing (non-)results
if /etc/rc.conf is modified during the boot process.

Since performance considerations make it infeasible to automatically detect
if the cached /etc/rc.conf parameters should be invalidated, provide a
mechanism for explicitly requesting that /etc/rc.conf be reloaded: Catch
SIGALRM and reload /etc/rc.conf if it is received.

Discussed on:	freebsd-rc
MFC after:	3 days

etc/rc

@@ -71,6 +71,11 @@ fi
 . /etc/rc.subr
 load_rc_config 'XXX'
 
+# If we receive a SIGALRM, re-source /etc/rc.conf; this allows rc.d
+# scripts to perform "boot-time configuration" including enabling and
+# disabling rc.d scripts which appear later in the boot order.
+trap "_rc_conf_loaded=false; load_rc_config 'XXX'" ALRM
+
 skip="-s nostart"
 if [ `/sbin/sysctl -n security.jail.jailed` -eq 1 ]; then
 	skip="$skip -s nojail"