pthread_setugid_np

[John Baldwin]

On Wednesday 27 May 2009 8:01:48 pm Zachary Loafman wrote:
> arch@ -
> 
> Isilon has need of per-thread impersonation. We're looking at
> implementing something like the pthread_setugid_np mechanism found on
> OS X, loosely documented in the code:
> 
> http://fxr.watson.org/fxr/source/bsd/kern/kern_prot.c?v=xnu-1228
> (see settid and setgroups1)
> 
> and some here:
> http://lists.apple.com/archives/perfoptimization-dev/2008/Jan/msg00043.html
> 
> Does anyone have strong objections to Apple's APIs here? There's
> obviously no portable itnerface to handle it, and it seems a little
> saner to just adopt someone else's API/semantics rather than reinvent.

I suppose you would implement this by having a new flag in td_pflags to 
indicate that the thread is using a private credential and use that to 
disable the automatic updating of td_ucred on syscall return and then just 
point td_ucred at the thread-specific credential?

Hmm, the XXX in Darwin's source about P_SUGID is probably meaningful for us as 
we still use that flag.  I would defer to Robert on how that should work 
though.

-- 
John Baldwin