Hi Folks, It's that BSD engineer again, trying to do something in linux and unable to see the _linux_ way to do it ;-) I have some kernel routine I'd like to get called, with the decision to call it made in user space. Obviously I could do this by making it into a full blown system call, but that's pretty much never the right answer, except for a quick hack. In FreeBSD, I'd make it into a sysctl, and have my user space script do something like "sysctl debug.call_my_hack=1" I'd then define call_my_hack to to be the type of sysctl that calls a procedure, using a convenient macro, and I'd be done. In linux I've determined that the /proc/sys interface is the preferred way to access sysctl's, but that even that is possibly deprecated in favour of sysfs. Documentation on implementing sysctl's is conspicuous by its absence, and much of what I've found applies only to the deprecated interface. In particular, the "strategy" routine appears designed for my purpose - but is never called if you come in to the kernel with read/write to /proc/sys/whatever. Probably I can get the effect I want by (ab)using the proc_handler function pointer - but is that what I "should be doing"? As for sysfs, it's tightly tied to the physical device hierarchy. I can't even find how one is supposed to deal with pseudo-devices. There do however seem to be a few interesting things in /sys/kernel which clearly have nothing to do with the device hierarchy. Probably checking their implementation will teach me how to use this ... but not whether it's the "right thing to do". For what it's worth, there is a pseudo-device driver involved, but no convenient /dev interface to issue ioctls on. (Probably calling it a pseudo-device exagerates its abilities.) As always, I'm looking primarily at 2.6.32, but want to write code that's good for the long haul, and potentially upstreamable. So, how would someone who thinks in linux go about doing this? Thanks for any enlightenment. -- Arlie (Arlie Stephens arlie@xxxxxxxxxxxx) _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
