devtmpfs and udev

devtmpfs and udev

[Ozan Çağlayan]

Hi,

When using devtmpfs, do we still have to copy /lib/udev/devices to /dev before running udev? What are the device nodes
that should always be created/copied statically?

And what about the links below[0]? Are they still required for a proper udev functionality?

ln -sv /proc/self/fd /lib/udev/devices/fd
ln -sv /proc/self/fd/0 /lib/udev/devices/stdin
ln -sv /proc/self/fd/1 /lib/udev/devices/stdout
ln -sv /proc/self/fd/2 /lib/udev/devices/stderr
ln -sv /proc/kcore /lib/udev/devices/core

[0]: http://www.linuxfromscratch.org/lfs/view/development/chapter06/udev.html

Regards,
Ozan Caglayan

Re: devtmpfs and udev

[Kay Sievers]

On Tue, Jan 26, 2010 at 17:38, Ozan Çağlayan <ozan@pardus.org.tr> wrote:
> When using devtmpfs, do we still have to copy /lib/udev/devices to /dev before running udev?

Yes. something like this is still the recommended way to initially fill /dev:
  cp -axT --remove-destination /lib/udev/devices /dev

> What are the device nodes
> that should always be created/copied statically?

No device nodes are needed with devtmpfs. Only if old-style on-demand
loading should work, /dev/ppp /dev/net/tun and /dev/lp0 might be there

> And what about the links below[0]? Are they still required for a proper udev functionality?
>
> ln -sv /proc/self/fd /lib/udev/devices/fd
> ln -sv /proc/self/fd/0 /lib/udev/devices/stdin
> ln -sv /proc/self/fd/1 /lib/udev/devices/stdout
> ln -sv /proc/self/fd/2 /lib/udev/devices/stderr
> ln -sv /proc/kcore /lib/udev/devices/core

Udev does not care, bash, or other shells might want them. These links
are usually just in /lib/udev/devices.

Thanks,
Kay