upgrade to karmic trashed /etc/hosts

[Nathaniel Smith]

I just upgraded today to karmic by running 'update-manager -d'. After the upgrade and reboot finished, my /etc/hosts file was trashed.

Before the upgrade (yay backups) it said:
---------
127.0.0.1 localhost
127.0.1.1 ged.localnet ged

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
---------

After the upgrade, it said:
---------
# Do not remove the following line, or various programs# that require network functionality will fail.127.0.0.1 localhost.localdomain localhost
---------

To be clear:
1) This file contains no newlines (even at the end of the file). It is one long mangled comment line.
2) All the usual IPv6 and localnet boilerplate has disappeared. (Maybe that's intentional? I'm not really sure what it's needed for anyway.)

WTF?

[Nathaniel Smith (njs)]

Also, note that this was not the only hostname-related weirdness I had created by the karmic upgrade: see also #432888, in case they are related.

[Nathaniel Smith (njs)]

And also see https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/432911

[Michael Vogt (mvo)]

Could you please run (in a terminal):

$ grep 'Do not remove the following line' /var/lib/dpkg/info/*

update-manager itself does not touch this file, but something in the packages upgraded might.

[Nathaniel Smith (njs)]

That grep command finds no hits.

OTOH:
  ~$ dpkg -S etc/hosts
  dpkg: *etc/hosts* not found.
So *something*'s creating it, I'm just not sure what.

/usr/lib/ubiquity/netcfg/netcfg seems to have some /etc/hosts-related code, though not the actual line you quoted. This is relevant because of bug 432911 (my upgrade decided to install and run oem-config).

[Nathaniel Smith (njs)]

Some googling around suggests that the particular phrasing in that comment ("various programs that require network functionality" etc.) is common on Redhat/anaconda-derived systems? Curious.

[Colin Watson (cjwatson)]

I think this is distinct from bug 432888; the string in Nathaniel's /etc/hosts does not appear anywhere in ubiquity/oem-config's code base.

[Colin Watson (cjwatson)]

Well, that said, the fact that /etc/hosts was removed on upgrade may have been the fault of oem-config running (bug 432180). However, the fact that malformed text was written to it (the missing newlines, etc.) is definitely a network-manager bug.

[Colin Watson (cjwatson)]

./src/NetworkManagerPolicy.c:320: g_string_append (new_contents, "# Do not remove the following line, or various programs");

[Thomas Hood (jdthood)]

NM no longer touches /etc/hosts.