Re: properly way of setting premissions for devices in /dev/

[Greg Troxel <gdt%lexort.com@localhost>]

Ramiro Aceves <ea1abz%gmail.com@localhost> writes:

> original files permission:
>
> crw------- 1 root wheel 72, 0 Jun 30 19:58 ugen0.00
> crw------- 1 root wheel 72, 1 Jun 30 19:58 ugen0.01
>
> files after permissions change:
>
> crw-rw---- 1 root wheel 72, 0 Jun 30 19:58 ugen0.00
> crw-rw---- 1 root wheel 72, 1 Jun 30 19:58 ugen0.01
>
> That works fine to make the receiver work as wheel group user..
>
> Before knowing that those two files were the right ones, I was
> desperately  tweaking /dev/usb* files. Receiver started to work as
> normal user.

As I understand it, we don't really have a scheme for assigning devices
to users.  Probably we should.

You can figure out what device is trying to be accessed and failing with
ktrace.   ktrace is hugely useful for debugging all sorts of problems
and well worth the time to learn.


I do what you do, not for rtl but other devices for other programs.  The
problem is that these changes are lost when the system is updated,
depending on the update method.  I therefore put the commands in
rc.local.  That mostly works, except that daemons get started before
they run, e.g. ups-nut.

It would be a great contribution to assess how every other system does
this and write up an analysis of pros and cons of approaches, including
security.  Right now we leave this to the sysadmin.