[systemd-devel] [HEADS-UP] systemd and Storage Daemons for the Root File System

[Lennart Poettering]

On Wed, 11.01.12 08:21, Jan Engelhardt (jengelh at medozas.de) wrote:

> 
> 
> On Tuesday 2012-01-10 23:24, Lennart Poettering wrote:
> >
> >http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons
> >
> >If you are involved with early-boot stuff, like building initrds, or are
> >doing storage stuff or are otherwise interested please have a look.
> >--------------
> >Processes (run by the root user) whose first character of the zeroth command
> >line argument is '@' are excluded from the killing spree, much the same way as
> >kernel threads are excluded too. [...]
> >Note that this functionality is only to be used by programs running from the
> >initramfs, and not for programs running from the root file system itself. 
> 
> Forcing the use of @ introduces a policy, which should preferably not be 
> done. Since programs started from the initrd obviously should be having 
> a /proc/*/{cwd,exe} symlinks pointing to the initramfs vfsmount.

They are in a different namespace, so that wouldn't work.

> If the initramfs vfsmount (rootfs) is mounted and/or moved (pivot_root) 
> somewhere into the main root, one can determine the special processes 
> simply by looking for that directory prefix on the procfs links.

It's not about figuring out which processes are from the initrd, it's
about figuring out which processes want to be excluded from the killing
spree. i.e. there are a number of processes from the initrd which stick
around during normal operation which are still to be killed in the
killing spree, most prominently plymouth.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.