Re: [Xen-devel] [PATCH] gdbserver-xen: fix corefile access

[Horms <horms@xxxxxxxxxxxx>]

On Thu, Mar 02, 2006 at 10:45:02AM +0000, Keir Fraser wrote:
> 
> On 2 Mar 2006, at 08:28, Horms wrote:
> 
> >This patch fixes corefile access by ensuring that the open fd
> >to the corefile (current_domid) is passed to the underlying
> >xc_routines as neccessary. Currently the prevailing pid is passed,
> >which works fine when attaching to a running domain, but fails
> >for the corefile case.
> 
> This is too gross.

Sorry about that.

> The correct fix is to update the xc_ptrace_core() interface to match 
> the xc_ptrace() interface. Kip Macy made the latter SMP aware, but 
> didn't fix up the former.
> 
> It should be easy to do -- note how xc_ptrace() takes a domid on 
> PTRACE_ATTACH, and vcpuid at all other times. xc_ptrace_core() should 
> take a fd on PTRACE_ATTACH, and vcpuid at all other times. Since we 
> don't dump SMP core files right now, vcpuid should either be ignored 
> for the time being, or fail the call if vcpuid!=0.

I didn't notice that, but I should have.

Are you suggesting that xc_ptrace_core() should record the fd passed
to it on PTRACE_ATTACH and use that later, presumably in current_domid?
If so, yes that does look very easy. If not, can you explain a little
further? In any case, I'll look into it tomorrow.

-- 
Horms

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