Context information on function return

[David Smith]

Alex Iribarren wrote:
> Hi,
> 
> I'm trying to use SystemTap to log network connections at the kernel
> level, so I'm trying to hook into connect(), accept() and a couple of
> other system calls.

... stuff deleted ...

> Currently, I'm using a rather nasty hack involving storing the
> parameters in a global array on function entry and reading and
> processing them on function return. It works, but I don't like it and
> there must be a better way.

If you are using a recent version of systemtap, you can access 
parameters in return probes.  Now, underneath the hood it is doing the 
same thing you are doing - generating an entry probe that saves the 
parameter in a global array (indexed by tid and a counter).  This has 
proved fairly robust.

-- 
David Smith
dsmith@redhat.com
Red Hat
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