misc/144400: [patch] /etc/rc.d/named - $named_wait_host needs an upper bound

andy wilson wilson.andrew.j at gmail.com
Mon Mar 1 21:50:03 UTC 2010

>Number:         144400
>Category:       misc
>Synopsis:       [patch] /etc/rc.d/named - $named_wait_host needs an upper bound
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Mar 01 21:50:02 UTC 2010
>Originator:     andy wilson
>Release:        8.0-RELEASE-p2
FreeBSD urania.tx.net 8.0-RELEASE-p2 FreeBSD 8.0-RELEASE-p2 #3: Wed Feb 24 11:30:46 CST 2010     jepp at urania.tx.net:/usr/obj/usr/src/sys/URANIA  i386
If you set $named_wait_host to a remote hostname and something is going wrong with the name resolution process for that particular hostname, your system will hang indefinitely. Some services (like ntpd) depend on being able to resolve remote DNS hostnames, but you would still want the system to come up if it is having trouble resolving $named_wait_host.

It would help to have an additional variable that specifies an upper bound for how long /etc/rc.d/named spends attempting to resolve $named_wait_host. That way $named_wait_host can be set to a remote hostname but your system will not be completely dependent on that hostname successfully resolving.

This addition would make it easy to solve problems like the one discussed here:  http://forums.freebsd.org/showthread.php?t=9171

Set up rc.conf with the following variables:


Then run: 
/etc/rc.d/named restart
I've attached patches for /etc/rc.d/named and /etc/defaults/rc.conf ; these patches add and document an optional $named_wait_max variable that sets the maximum number of seconds that rc.d/named will wait while trying to resolve $named_wait_host.

Patch attached with submission follows:

--- /etc/rc.d/named.orig	2010-03-01 14:25:19.000000000 -0600
+++ /etc/rc.d/named	2010-03-01 14:26:58.000000000 -0600
@@ -98,11 +98,16 @@
 named_poststart () {
+        local count
+        count=0
 	if checkyesno named_wait; then
-		until ${command%/sbin/named}/bin/host $named_wait_host >/dev/null 2>&1; do
+		until ${command%/sbin/named}/bin/host $named_wait_host >/dev/null 2>&1 || ([ $named_wait_max ] && [ $count -gt $named_wait_max ]) ; do
 			echo "	Waiting for nameserver to resolve $named_wait_host"
+                        count=$((${count} + 1))
 			sleep 1

--- /etc/defaults/rc.conf.orig	2010-03-01 15:07:19.000000000 -0600
+++ /etc/defaults/rc.conf	2010-03-01 15:13:24.000000000 -0600
@@ -259,6 +259,9 @@
 named_symlink_enable="YES"	# Symlink the chrooted pid file
 named_wait="NO" 		# Wait for working name service before exiting
 named_wait_host="localhost" 	# Hostname to check if named_wait is enabled
+#named_wait_max="60"            # Maximum number of seconds named_wait will wait
+                                # while attempting to resolve named_wait_host.
+                                # If not set, it will never stop waiting.
 named_auto_forward="NO" 	# Set up forwarders from /etc/resolv.conf
 named_auto_forward_only="NO" 	# Do "forward only" instead of "forward first"


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