Problem with udev/ifupdown (PATH is not set)

[Ignacio García Pérez]

I want udevd to automatically set up any SLIP interface as soon as it 
shows up (which is done using slattach), so I have this simple rule:

(actually, this will bring up ANY network interface as soon as it shows up)



ACTION=="add", SUBSYSTEM=="net", RUN+="/sbin/ifdown $env{INTERFACE}"



But it doesn't work. It turns out that udevd does not set the PATH 
environment variable for the external programs it runs. Since ifupdown 
calls several exteral programs (ifconfig, route, etc) WITHOUT specifying 
their path, they are simply not found and the whole thing does not work 
at all.

The following rule solves the problem:



ACTION=="add", SUBSYSTEM=="net", 
ENV{PATH}="/usr/sbin:/usr/bin:/sbin:/bin", RUN+="/sbin/ifdown 
$env{INTERFACE}"



So I have a solution. But the problem is I don't think this is right. 
I'm forced to first set ENV{PATH} for every rule that runs an 
executable  which MIGHT call other executables.

Should udevd be setting a default PATH value?
Should ifupdown call the external programs using the complete path 
(/sbin/ifconfig and such instead of just "ifconfig")?
Should ifupdown set a default PATH value before calling external 
programs (at least when it detects PATH is not already set?

IMHO the third option is the one that makes most sense. Since ifupdown 
as it is now does not specify complete paths to external programs, it is 
actually expecting PATH to be set, but in certain situations like this 
one it is not going to be set.

Nacho.