Re: [KLUDGE PATCH] Linux vsyscall DSO support

Andrew Cagney
2004-04-08T21:30:07Z

Roland, FYI.

Last time this was discussed the observer was identified as the correct
mechanim for hooking this in. That's why I'm currently overhauling that
code.

Andrew

> Perhaps you recall the discussion here some months back about what hook to
> use in Linux targets for the detection of the vsyscall DSO. The last time
> I asked here about a resolution on how best to do this, I got no feedback.
> I hope we can now jumpstart the effort to find the right way to implement
> this. To get things rolling again, here is a patch that I am not
> suggesting for inclusion, but does work. This is a kludge to overload the
> solib hooks with target-specific code. These solib hooks get called at
> roughly (or perhaps even precisely?) the correct places where the vsyscall
> DSO checks ought to happen. A reminder, the appropriate places are when
> gdb thinks the address space might be a fresh layout from what it knows,
> i.e. first attach (or any attach?), after exec, and on opening a core file.
>
> As I said, this code works for me. (It requires symbol_file_add_from_memory,
> which is in the patch I just re-posted.) It seems doubtful this is the
> ultimately desireable approach to wedging this code in where needs to be.
> But it's what I've got, and as I said I'm still waiting for more feedback to
> conclude on exactly what the preferred better thing to do is.
>
>