froggy

[Chris Moller <cmoller at redhat dot com>]

This is a note I sent to Tom and Eric last night:

> The incompleteness of the froggy_ptrace() ptrace() replacement has been
> bugging me since I started it--it /only/ replaces ptrace, whereas
> froggy/utrace is really capable of replacing ptrace, waitpid, and signal
> handling, all in a coherent fashion, and with greater capabilities than
> the individual utilities can offer.
>
> This suggests to me that the right thing to do isn't to piecemeal
> replace all the ptrace calls with froggy_ptrace--functionally, this buys
> us almost nothing other than the ability to aay "we don't use ptrace,"
> and it slows things down.  I suspect the real answer is to write a new
> gdb backend, based on gdb/config/i386/linux.mh (and, I guess,
> gdb/config/i386/linux64.h).  (Judging from something you said a while
> back, this may have been obvious to you all along; I just got my Aha! a
> couple hours ago.)
>
> I've spent the last hour or so looking over the code represented by the
> linux.mh config and adapting it to froggy is a long way from
> trivial--several months, at a minimum, possibly as much as six months or
> more.

After a bit more discussion today, it looks like this is the way we'll
go.  Eric would like to see it ready for Fedora 11, which freezes in
April, and I think that's likely doable but probably involves omitting
the uprobes breakpoint stuff (ubp) until after that.  Not, I suspect,
that anyone's all that wedded to froggy per se, but it might also
involve a froggy-based module and i/f library customised for gdb.

Comments welcome.

-- 
Chris Moller

  I know that you believe you understand what you think I said, but
  I'm not sure you realize that what you heard is not what I meant.
      -- Robert McCloskey

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