Re: [gentoo-user] Re: Change from udev to eudev?

On Thu, Jun 09, 2016 at 10:18:01PM -0400, Jonathan Callen wrote

> Actually, you no longer need a user-space device manager at all, unless
> you want to be able to access device nodes under /dev as a user that
> isn't UID=0 or has CAP_DAC_OVERRIDE.  The kernel provides a devtmpfs
> filesystem that will have every single device node that udev used to
> create (udev no longer even creates the devices -- it just relies on
> devtmpfs doing so), but most of them will be owned by 0:0 (root:root)
> with permissions 0600; excepting certain nodes like /dev/null or
> /dev/zero, which will be owned by 0:0 with permissions 0666.  One other
> thing that udev does that you might rely on is to create symlinks like
> /dev/disk/by-label/*, which can be used by mount(8) if you specify
> LABEL=foo in /etc/fstab.  The only other things that I'm aware of udev
> doing is to rename network devices and (possibly) to notify other
> applications of changes, somehow (but I'm not sure that it actually does
> that).
>
> If you don't actually need any of that (you are working on an embedded
> system where you only need root anyway, for instance), then you can just
> use a bare devtmpfs without a device manager changing permissions,
> adding links, etc.

  Interesting.  In the initial panic after the announcement that udev
would be subsumed by systemd, I started what went on to become the
Gentoo wiki entries at...

 https://wiki.gentoo.org/wiki/Mdev
 https://wiki.gentoo.org/wiki/Mdev/Automount_USB
 https://wiki.gentoo.org/wiki/Mdev/Automount_USB/automount

  I wonder if it would be possible to set up a functional multi-user
devtempfs-based system with appropriate permissions being granted in
/etc/sudoers.d/  It would certainly be an interesting project.

-- 
Walter Dnes <waltdnes@××××××××.org>
I don't run "desktop environments"; I run useful applications