Bug#984846: netcfg: Default hostname hardcoded in netcfg-common

[Arnaud Rebillout <arnaudr@kali.org>]

Package: netcfg
Severity: normal
Tags: d-i
User: devel@kali.org
Usertags: origin-kali

Dear Maintainer,

the default hostname "debian" is hardcoded in two places in the file
netcfg-common.c:

https://salsa.debian.org/installer-team/netcfg/-/blob/master/netcfg-common.c#L1043
https://salsa.debian.org/installer-team/netcfg/-/blob/master/netcfg-common.c#L1069

This was reported in the Kali Linux bugtracker [1].

For Kali, we set the default hostname to 'kali' in the file
'debian/netcfg-common.templates', key 'netcfg/get_hostname', so that the
installer proposes it as the default hostname. It works well, however
one of our user noticed that if they enter an invalid hostname, the
default hostname is set back to 'debian' (since it's hardcoded in
netcfg-common.c).

It would be nice if instead it would default to the value that is set in
'netcfg/get_hostname'. However I'm nost sure how to achieve that, as
I'm not familiar with the netcfg code at all, and it's not clear if we
can still get this value at this moment in the code, or if it has been
overwritten by the user's input.

Cheers,

  Arnaud

[1] https://bugs.kali.org/view.php?id=7070