On 01/12/2012 01:32 AM, Mark A. Grondona wrote:
On Wed, 11 Jan 2012 17:23:34 -0700, Moe Jette<je...@schedmd.com> wrote:
> Matthieu,
>
> I do not see any problem moving the code as you suggest, although it
> will prevent error messages being sent to the srun command from some
> possible failure conditions. The change could also result in failures
> that are not obvious to us looking at the code right now.
>
> Something that we might consider is adding a new spank plugin function
> to be made at an earlier point in the slurmstepd code. That should be
> a simple and low risk change.
spank_init() is where the plugins are actually loaded by plugstack.c,
so it would have to be that call which is relocated.
Mattheiu, is the relevant auks call made from a slurm_spank_init()
callback, or slurm_spank_init_post_opt()?
One thing I might want to do is break spank_init_post_opt() out of
spank_init() on the slurmd side, so that it could be run later
in the code (after IO files are set up). However, if auks or other
security related plugins need to handle options from the user
before IO can be set up, this might not work.
The relevant auks call is made from a slurm_spank_init().
I think that the main problem here is that we definitely need to
initialize security related spank plugins and the PAM stack prior to try
to open any files in user context (including IO set up which can result
in opening stdout/stderr files). Multiple scenarios would require that,
like using NFSv4, AFS, enforcing a particular selinux policy for user's
files management... I am trying to figure out how to shift calls for
that purpose.
The place where the CWD is changed (_fork_all_tasks) seems to be the
best place to put the IO setup as it is the place where we are sure that
sufficient rights are present for a user to access files and so to
create them if necessary due to IO redirection. I will give it a try and
give you my feedback.
Regards,
Matthieu
