[Nut-upsuser] Getting a Plexus 500VA to work with NUT

Charles Lepple clepple at gmail.com
Mon Jan 24 14:18:24 UTC 2011

On Jan 23, 2011, at 2:16 PM, Paul Banks wrote:

> $ ./blazer_usb -a rupert -DDDDD -u root

^ If this is in a non-root shell, this won't work.

NUT has no hooks to go from a non-root user ID to root, nor can it  
change from one non-root user to another non-root user. (To do so  
would require setuid binaries, or calling an existing setuid tool like  

The "-u root" option is to override the default behavior when started  
as root, which is to change to the non-root user specified at  
configuration time (usually "nut", or the last-resort "nobody").

> Note that I get the above output when running the command from a
> normal non-root user. (not nut user as that has no shell). If I run
> the same as root I get a different error saying it couldn't connect to
> UPS at all - I originally was going to post about that when I realised
> that I probably should be running blazer-usb command as non-root. If
> it SHOULD work to launch the driver directly as root then let me know
> and I'll post the output as that might identify better the actual
> issue here.

If you want to invoke a driver from a non-root account, then "-u"  
won't have an effect, and that non-root account should be the one  
specified at configuration time.

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