Re: /run and read-only /etc
Clearly what is needed here is an API for resolver updates that uses the
observer pattern. Packages that wish to be informed of a resolver
change install a notifier-method script in a resov.d directory. libc or
whatever includes one that updates the /etc/resolv.conf file. named can
include one, etc, etc.
Whenever dhcp/ppp/whatever decides to change the info, it passes it in a
standard format (doesn't matter who changed it, or who is receiving the
update), hence the API. It then does a run-parts on the resolv.d dir.
So each provider (dhcp/ppp/etc) doesn't have to "support" all the
different packages that are interested in the info, and neither do the
packages have to "support" specific interface autoconfig schemes
(ppp/dhcp).
In Debian, there should possibly be a policy decided upon. (what the dir
is, what API is, etc)
Cheers,
Jeremy
On Wed, 2003-04-09 at 06:22, Bernhard R. Link wrote:
> > An example
> > =---------
> > /run/resolvers/eth0 Created by the DHCP client process that
> > has configured interface eth0.
> > "resolv.conf"-formatted info for eth0
> > /run/resolvers/ppp0 Created by the pppd process that has
> > created ppp0.
> > "resolv.conf"-formatted info for ppp0
> > ...
> > /etc/resolvers/default Included in base-files
> > Generates /run/resolv.conf which is a
> > composite of the above files. The local
> > admin can link /etc/resolv.conf to that file
> > if s/he doesn't run a local DNS cache.
>
> Hm, I never worked with anything dynamic like dhcp or ppp or even
> several of them. So I wanted to ask why there are entries for
> several configurations. (When I remember correct a program resolving
> an address has no way to specify an interface for doing so).
>
> I'm also curious, why the parts should be "resolv.conf" formatted.
> Nameserver entries can easily be combined, but domain or search
> statements seem a bit more tricky. (are they transported by dhcp or
> ppp at all?) Might a more strict format of theese files (as they
> are written/read by programs) useful?
>
> > /etc/resolvers/named Included in bind package
> > Generates /run/bind/named.conf.forwarders
> > which is a "forwarders { ... }" statement
> > listing all nameserver addresses listed in
> > in the files above. Then reloads named.
> > The admin can include this file inside the
> > "options { ... }" statement in named.conf.
> > /etc/resolvers/dnscache Included in djbdns package
> > Does appropriate stuff to configure and
> > notify dnscache.
> > ...
> > /sbin/update-resolvers Does a run-parts on /etc/resolvers
> > Is called by ifup/ifdown, pon/poff.
>
>
> Are multiple "forward-provider" reasonable? Or would an alternative
> link be better?
>
> Hochachtungsvoll,
> Bernhard R. Link
>
> --
> Sendmail is like emacs: A nice operating system, but missing
> an editor and a MTA.
>
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