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

David C. Rankin drankinatty at suddenlinkmail.com
Sat Dec 14 18:37:16 UTC 2013

On 12/14/2013 07:20 AM, Charles Lepple wrote:
> On Dec 14, 2013, at 4:19 AM, David C. Rankin wrote:
>> lsusb shows:
>> Bus 004 Device 002: ID 0764:0501 Cyber Power System, Inc. CP1500 AVR UPS
> I am guessing that 'ls -l /dev/bus/usb/004/002' shows that the device node is
> not owned by the NUT gid?
crw-rw-r-- 1 root root 189, 385 Dec 14 12:31 /dev/bus/usb/004/002

It does now.

>> Why doesn't "upsdrvctl start" allow nut to find the UPS when it can find it
>> without a problem with the options "-u root start <upsname>"?
> The NUT USB drivers use libusb, which need read/write access to the /dev node
> for the UPS. The "-u root" hack tells the driver not to drop privileges from
> root to the 'nut' system user.

That's what I thought was going on, I just didn't know where to fix the usb dev

>> Second why doesn't nut create the .pid files and the usbhid file with
>> root:nut ownership?
> Mostly because the "-u root" option is meant to be a temporary fix while
> tracking down permissions issues. Hopefully we can figure out the underlying
> permissions issue, and we can table that question.

I found another really good article that describes writing the udev files to fix
these issues. The url is:


I will test with the new ubs dev permission and report back. Thank you for your
help Charles.

David C. Rankin, J.D.,P.E.

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