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? > 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. > 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. > These problems have been around a while. I used nut for a long time before > these problems popped up, and I would like to help get them solved. I know the > hotplugging, etc. causes problems, but it is hard to understand how it used to > work just fine and now doesn't. Let me know what else I can send, and I'm > happy > to do it. I haven't mapped out all of the combinations, but we've heard similar issues from people running older versions of NUT (which worked when they were released) when it comes to hotplug/udev permissions on newer Linux systems. I'm frustrated as well - all I can think is that there is some subtle change in how the kernel and udev are creating the device nodes. See: http://thread.gmane.org/gmane.comp.monitoring.nut.user/8180 http://thread.gmane.org/gmane.comp.monitoring.nut.user/8207 Apparently the auto-generated udev rules file does not successfully set the permissions on the UPS USB device, but simpler hand-written rules often suffice. If anyone has suggestions on udev debugging techniques (besides sprinkling the source code with log statements, which I would rather not do on a "production" system), I'm listening. -- Charles Lepple clepple@gmail _______________________________________________ Nut-upsdev mailing list [email protected] http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/nut-upsdev
