Re: sysfs vs. d80211 configuration

On Mon, 14 Aug 2006, Johannes Berg wrote:

In my seemingly never-ending quest to actually use the d80211 stack for 
something useful I just wanted to write a small setuid tool that:
* creates and opens a new monitor interface
* drops priviledges
* ... does things with received frames ... (not interesting for this 
discussion)
* removes new monitor interface

So I figured I'd just keep an fd open to 
/sys/class/net/mymonitorinterface/remove_iface to which I could write the 
interfaces name after I was done with it. However, when writing to that fd I 
got -EACCESS because it checks for CAP_NET_ADMIN.

Why not have the tool create a monitor interface, open it, and fork; the 
child drops privileges and does the reading, and the parent wait(2)s for 
the child and removes the interface once it has collected the child?

 			Alexey