[Nut-upsdev] Nut (git) upsdrvctl fails without "-u root start <upsname>", upsd fails on state file GID

Charles Lepple clepple at gmail.com
Sun Dec 15 03:04:17 UTC 2013

On Dec 14, 2013, at 4:23 PM, David C. Rankin wrote:

>  Do you know if the problem with upsdrvctl being able to probe/connect to the
> usb devices is the result of some default permission change in Linux in general.
> It seems to me that since nut used to work right out-of-the-box, then all/most
> distros must have had the default permissions on usb nodes set to 0666, where
> currently they are 0664. (this is just brainstorming)

Sounds logical, but I think the auto-generated hotplug and udev files properly changed the group for a while after the permissions changeover to 0664.

>  Is there someway nut can be modified to probe the 0664 permission usb devices
> and then connect as root before dropping permissions back to the "nut" gid?

Given that the udev method should still work (and seems to, for handcrafted udev rules files), I would like to run that to ground first.

Although this is conceptually similar to opening a listening socket as root, then forking and dropping privileges, I have a nagging feeling that it won't be as easy for USB.

Charles Lepple
clepple at gmail

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