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From: "Matt Emmerton" <matt@gsicomp.on.ca>
Subject: Re: Request for swapcontext and getcontext to be ported to our libc [ revision 3 ]
Date: Mon, 15 Jan 2007 15:43:51 -0500
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> :I agree with the assessment.  Last night I moved all the requisite bits
from
> :kernel-space into libc, with the exception of the low-level
> :[get|set]_mcontext routines.  (My Intel assembly knowledge is very
limited,
> :especially for anything after the 8086, so I could use some help to write
> :this code.)  I'm almost done the syscall work to get/set the signal mask
and
> :pending signal mask, so should have something up on the web before the
end
> :of the afternoon (EST) for review.
> :--
> :Matt Emmerton
>
>     I can do that bit.  If you post the bits you have I can supply and
>     test the low level switch code.
>
> -Matt
> Matthew Dillon

A first cut of the libc-based implementation, using a (new) syscall to
get/set the signal its is available, and can be found here:
http://www.gsicomp.on.ca/~matt/dfly/ (rev3, bottom of page)

Note that this implementation is not complete, as it is missing the userland
get/set_mcontext code.  I'm sure I've also missed some nuance wrt signal
handling (locking, ordering, etc) in the design and use of the new sigmask
syscall.

--
Matt Emmerton