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 <[email protected]> I don't run "desktop environments"; I run useful applications
