Monitoring attributes of the device

Monitoring attributes of the device

[Shashank KotaSathish]

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.

Regards,
Shashank K S

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Re: Monitoring attributes of the device

[Greg KH]

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

RE: Monitoring attributes of the device

[Shashank KotaSathish]

Modifying kernel. Hmmm An intriguing idea. Perhaps some other time. For the current requirement I believe netlink will do. Thanks for the clarification. I should have understood the same when udevadm monitor --kernel did not give any output when I unplugged the network cable.

Regards,
Shashank K S
-----Original Message-----
From: Greg KH [mailto:greg@kroah.com]
Sent: Thursday, January 21, 2010 11:57 AM
To: Shashank KotaSathish
Cc: linux-hotplug@vger.kernel.org
Subject: Re: Monitoring attributes of the device

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

http://www.mindtree.com/email/disclaimer.html

Re: Monitoring attributes of the device

[Stephen Hemminger]

On Fri, 22 Jan 2010 09:30:18 +0530
Shashank KotaSathish <Shashank_KotaSathish@mindtree.com> wrote:

> Modifying kernel. Hmmm An intriguing idea. Perhaps some other time. For the current requirement I believe netlink will do. Thanks for the clarification. I should have understood the same when udevadm monitor --kernel did not give any output when I unplugged the network cable.
> 
> Regards,
> Shashank K S
> -----Original Message-----
> From: Greg KH [mailto:greg@kroah.com]
> Sent: Thursday, January 21, 2010 11:57 AM
> To: Shashank KotaSathish
> Cc: linux-hotplug@vger.kernel.org
> Subject: Re: Monitoring attributes of the device
> 
> 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 :)

Or monitor with netlink like proper tools do (see ip monitor, netlink, netplugd, quagga, ...)



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