Adding operating-system field for a custom /etc/profile.

[Alex Kost]

This is a continuation of the discussion beginning here:
<http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20255#44>.

To sum up: I would like to have a possibility to use my own /etc/profile
instead of the default one, but Ludovic doesn't want to provide me this
freedom :-(

Ludovic Courtès (2015-11-23 17:31 +0300) wrote:

> Alex Kost <address@hidden> skribis:
>
>> Ludovic Courtès (2015-11-23 02:04 +0300) wrote:
>>
>>> Alex Kost <address@hidden> skribis:
[...]
>>>> … what I suggest now is just to give an option to avoid generating the
>>>> default /etc/profile.  What about making an 'operating-system' field for
>>>> this file (similar to 'sudoers-file' or 'hosts-file')?  So when such
>>>> 'profile-file' is specified, it will be used instead of the default one
>>>> (of course, it should be mentioned in the manual that it's only for
>>>> those users who are sure what they do).
>>>
>>> I think we could make an /etc/profile-service that receives snippets
>>> meant to be glued together into the final /etc/profile.  Users could
>>> specify the top or bottom of the file.
>>>
>>> There could be a combined-search-paths-service that implements the
>>> solution I proposed here.
>>>
>>> WDYT?
>>
>> I agree, the more ways to change a default behaviour, the better.
>> Although I will not use these things if there will be ‘profile-file’
>> field that allows to specify my own "/etc/profile".
>
> [...]
>
>> Great!  So is it OK to send a patch for adding ‘profile-file’ field?
>
> Hmm, I’m not sure if we want to give direct access to /etc/profile like
> this.

Oh, no!  If there is one person (me) who wants to have a full control on
his /etc/profile, there may be the others with the same wish.

> The problem is that several things in there are here to make the system
> work, and to to make it conform to the ‘operating-system’ declaration,
> such as:
>
>
> export LANG="en_US.utf8"
> export TZ="Europe/Paris"
> export 
> TZDIR="/gnu/store/rwvf6xqgsyb8bmpi7rwk9fildnwvzrv5-tzdata-2015c/share/zoneinfo"
>
> # Tell 'modprobe' & co. where to look for modules.
> export LINUX_MODULE_DIRECTORY=/run/booted-system/kernel/lib/modules

Yes, that's why I suggest to add a note to the manual about a danger of
using this field.

> The risk I see with adding a raw ‘profile-file’ option is that newcomers
> may end up getting rid of such things without really noticing, and then
> getting a broken system.

But a newcomer will learn about this option only if (s)he reads the
manual with the warning I've mentioned.  For me, your phrase sounds
like: «We will not provide "rm" command, because a newcomer may
accidentally run "rm -rf ~"».  Please give me an opportunity to shoot
myself in the foot!

Besides will the system really be broken?  What do you mean?  Even if
/etc/profile is empty, the system will boot successfully and a user
could login, no?

> What about instead giving a way to populate the top and/or bottom of
> this file?  Controversial parts, if any, could still be turned on and
> off by adding or removing services that add these lines?

It is better than nothing, but it is not sufficient IMO.  Any part of
/etc/profile can be controversial (you'll never know what a user would
like to change), so I think providing an option to change this file
completely is essential.

But I agree that appending/prepending some lines may also be useful for
those who like to keep the default /etc/profile and who just want to add
something to it.

> I think we should open a separate bug report to discuss this.

I agree that it's not related to this bug, so I'm sending this message
to guix-devel list.

-- 
Alex