Re: Monitoring attributes of the device

[Greg KH <greg@kroah.com>]

On Thu, Jan 21, 2010 at 10:57:26AM +0530, Shashank KotaSathish wrote:
> Hi,
> 
>       I wanted to know is it possible to write a rule for the udev which will run a program when the attribute of the device changes. For example if the ethernet plug is removed, the attribute "carriers" of net class will change from 1 to 0. To track this change i wrote the following rule in the /etc/udev/rules.d/70-persistent-net.rules file
> 
> SUBSYSTEM="net", DRIVERS="?*", ATTR{carrier}="0", ATTR{address}="00:0c:29:27:a2:95", ATTR{dev_id}="0x0", ATTR{type}="1", KERNEL="eth*", RUN+="/bin/up.sh"
> 
>  up.sh will echo some thing in to the text file  in my home directory.
> But the up.sh is not getting executed.  Thanks in advance.

No sysfs event is getting emitted by the kernel when this attribute
changes.  You need to modify the kernel to create such an event, and
then your script can run.

Or you can just use ethtool and detect the carrier change that way, like
the rest of the world does :)

Hope this helps,

greg k-h