Re: [ptxdist] Resend: Home dir fixup for root in systemd

[David Jander <david@protonic.nl>]

On Tue, 26 Jul 2016 19:50:09 +0200
Guillermo Rodriguez Garcia <guille.rodriguez@gmail.com> wrote:

> Hi David,
> 
> 2016-07-26 16:00 GMT+02:00 David Jander <david@protonic.nl>:
> 
> >
> > Dear Guillermo,
> >
> > Thanks for your reply.
> >
> > On Tue, 26 Jul 2016 15:19:59 +0200
> > Guillermo Rodriguez Garcia <guille.rodriguez@gmail.com> wrote:
> >  
> > > Wouldn't it be easier to either use a custom /etc/passwd, or create a  
> > /root  
> > > dir in the filesystem ? That sounds better than patching systemd.  
> >
> > Maybe it would be better to change the default /etc/passwd (and everywhere
> > else) in ptxdist then...
> >  
> 
> I think that the default /etc/passwd (and many other files that are
> distributed
> with ptxdist) should be taken just as generic examples. Ptxdist BSPs are
> expected

Generic examples are expected to at least be semantically correct. This isn't.

> to customize any files as needed and in fact ptxdist is already prepared to
> handle
> that: Just drop your customized files in the projectroot/  dir in your BSP
> and they
> will be picked up, as long as the relevant rules files use the
> install_alternative
> macros.

Of course one can customize these files. But just as with any other default
setting or example configuration, the user expects these settings to be
correct. That said, if I start a new ptxdist project and take the
example /etc/passwd as a starting point I'd assume that it's always best to
not touch defaults I do not need to change for my specific purpose, so I'd
probably leave $HOME=/home just the way it is. The expectation is for that
default to work and behave correctly.
In case I wasn't clear enough: I am not asking for a workaround, I am offering
a fix for a bug in PTXdist and asking for a proper way of submitting that fix.

> > The problem is that what /etc/passwd says is mandatory. The home directory
> > has
> > a special meaning to the user. You can get to the home directory via $HOME
> > passed in the environment, or via the NS-switch (getent) lookup. They are
> > supposed to be the same.
> > systemd has hardcoded defaults in source-code, which by definition is ugly
> > as
> > hell, but the reason is clearly to avoid potentially expensive, blocking
> > NSS-lookups in the early boot stages, so it is understandable. It would be
> > a
> > lot better if there was some configuration setting read from a file I
> > guess,
> > but alas.
> > On PTXdist now (with the default, shipped /etc/passwd), a user logging in
> > as
> > "root" via, say a serial console getty, will have a different $HOME than a
> > systemd service started with User=root. This is bad, and can potentially do
> > funny things people will not like.
> > To solve the problem, there are really only two options AFAICS:
> >
> >  1.- Change PTXdist and all places in it that assume the $HOME=/home for
> > root.
> >  No idea how many places that are, nor how many users already depend on
> > this
> >  historic assumption.
> >
> > or
> >
> >  2.- Patch systemd to adapt to the reality of PTXdist.
> >  
> 
> Yes, or
> 
> 3.- Customize the files in your BSP :-)

No. Like I said in my previous e-mail (the part after this part, that you
omitted from the quote), this way the default PTXdist stays broken and my
intention is to fix just that.

Best regards,

-- 
David Jander
Protonic Holland.

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