[launchd-dev] launchd & mDNSResponder: "Policy denied Mach service lookup"

[Björn Giesler]

Hi,

I've recently migrated to a new MacBook Pro, and since that migration,  
found that Bonjour no longer worked, and indeed that all applications  
that used Bonjour just hang. I've traced this to what looks like a  
problem in the interaction of mDNSResponder and launchd; the log  
messages I get are lots of

com.apple.launchd[1] (com.apple.mDNSResponder[2551]): Policy denied  
Mach service lookup: com.apple.distributed_notifications.2

etc.etc. with different services.

I don't yet quite understand how launchd and launched processes  
interact. Why is launchd responsible for service lookups for other  
applications? Where are policies stored? etc. The manpage says nothing  
about this.

I've tried looking for the above message in the launchd code and found  
it in launchd_core_logic.c in the SULeopard branch, which introduces  
the mspolicy_* functions, but I'm afraid I can't make much sense of  
it. I'll try to compile my own launchd and step through it, but it  
would be nice if somebody could push me in the right direction. (Is  
there even some documentation on this?) As a Unix rc guy, launchd is a  
twisty maze of passages, all alike...

Thanks in advance & Regards,
Björn