I want to be able to refer to systems on both my home and work networks by their hostnames rather than their fully-qualified domain names, so, ‘prey’ instead of ‘prey.thestaticvoid.com’ and ‘acad2′ instead of ‘acad2.es.gwu.edu’.

The Problem

I would typically set my home and work domains as the search setting in /etc/resolv.conf. Unfortunately, either NWAM or the Solaris DHCP client (I haven’t decided which) overwrites resolv.conf on every new connection. DHCP on Linux does the same thing, but I can configure it by editing dhclient.conf (or whatever is being used these days, it’s been a while. I think I just set my domains in the NetworkManager GUI and forget about it).

The Solaris DHCP client configuration is not nearly as flexible, and neither is NWAM which gives you the option of replacing resolv.conf with information supplied by the DHCP server, or provided by you, but not a mix of both. I do like having the nameservers set by the DHCP server, so supplying a manual configuration is not an option.

What I Tried

The first thing I tried was setting the LOCALDOMAIN environmental variable in /etc/profile. From the resolv.conf man page:

You can override the search keyword of the system
resolv.conf file on a per-process basis by setting the
environment variable LOCALDOMAIN to a space-separated list
of search domains.

I thought, great, a way to manage domain search settings without worrying about what’s doing what to resolv.conf. It didn’t work as advertised:

% LOCALDOMAIN=thestaticvoid.com ping prey
ping: unknown host prey
% s touch /etc/resolv.conf
% LOCALDOMAIN=thestaticvoid.com ping prey
prey is alive
% LOCALDOMAIN=thestaticvoid.com ping prey
ping: unknown host prey

Next, I considered adding an NWAM Network Modifier to set my search string in resolv.conf after a new connection is established. This worked reasonably well, but didn’t handle the case when you switch from one network to another, for example, from wireless to wired. The only events in NWAM that can trigger a script when the network connection changes happens before DHCP messes up resolv.conf.

Finally, in the course of my testing, I discovered that the svc:/network/dns/client service was restarting with every network connection change. I looked into its manifest and saw that it was designed to wait for changes to resolv.conf:

So I could write another service which depends on dns/client and restarts whenever dns/client does and I would have the last word about what goes into my configuration file!

My Solution

I wrote a service, svc:/network/dns/resolv-conf, with the following manifest:

which calls the script, /lib/svc/method/dns-resolv-conf containing:

So now I can set my search options like:

% svccfg -s resolv-conf setprop 'options/search="thestaticvoid.com es.gwu.edu"'
% svcadm refresh resolv-conf
% svcadm enable resolv-conf
% cat /etc/resolv.conf
domain  iss.gwu.edu
search iss.gwu.edu thestaticvoid.com es.gwu.edu
nameserver  161.253.152.50
nameserver  128.164.141.12

Problem solved! Or at least worked-around in the least hacky way I can!

This service should run sometime after the network is started but before the zones are started. Load it in with svccfg -v import vnic.xml and create an instance of the service for each of the VNICs that you want to start. For example, if you want to start vnic0 on boot:

# svccfg -s vnic add vnic0
# svcadm refresh vnic0
# svcadm enable vnic0

UPDATE: Build 132 is out an this functionality has been integrated as the svc:/network/datalink-management:default service. The services that were added above can be removed by running svccfg delete vnic.

First, the script which should go into /lib/svc/method/sound-mixer:

Second, the manifest which can be saved anywhere and loaded with svccfg -v import <manifest>:

UPDATE: In b130, the audioctl command replaces mixerctl. In the sound-mixer script above, change /usr/sbin/mixerctl -r $ctl_file to /usr/bin/audioctl load-controls $ctl_file and /usr/sbin/mixerctl -f -s $ctl_file to /usr/bin/audioctl save-controls -f $ctl_file.