[launchd-dev] OnDemand USB Software

[Quinn]

At 23:23 +0100 17/3/08, Mike Fischer wrote:
>So far, looking at tn2083 and the man pages, I don't see any way to 
>have a depency on USB or IOKit in general. Am I missing something 
>here?

No, you're not missing something.  This is a much-requested feature 
that we're tracking as <rdar://problem/4551362>.

>If there is no direct support would it make sense to have a very 
>small, lightweight daemon always running that registers for IOKit 
>IOServiceAddMatchingNotification notifications and creates a 
>semaphore file that can be used to trigger the launch of the real 
>daemon for example?

That's a fine way to do it.  I probably wouldn't use a semaphore 
file, because it persists in the file system.  However, there are 
numerous other options available to you.  If I was doing this, I'd 
probably have your main daemon register a UNIX domain socket and have 
your lightweight daemon connect to that socket to trigger a launch.

>BTW: This would be mainly for Leopard, although Tiger would be 
>interesting too.

This approach would work just fine on 10.4.x (x >= 6 if you use UNIX 
domain sockets).

S+E
-- 
Quinn "The Eskimo!"                    <http://www.apple.com/developer/>
Apple Developer Relations, Developer Technical Support, Core OS/Hardware