Re: [PATCH] Move vgdb special case into remote_filesystem_is_local

[Gary Benson <gbenson at redhat dot com>]

Pedro Alves wrote:
> On 05/15/2015 10:02 AM, Gary Benson wrote:
> > Pedro Alves wrote:
> > > On 04/27/2015 03:51 PM, Gary Benson wrote:
> > > > Valgrind GDB (vgdb) presents itself as a remote target but
> > > > works on the local filesystem.  gdb_bfd_open contained a
> > > > special case to make vgdb work with "target:" sysroots, but
> > > > the implementation meant that GDB would fall back to the local
> > > > filesystem if *any* to_fileio_open method failed with ENOSYS
> > > > for *any* reason.
> > >
> > > Can you give an example target where we'd want this to behave
> > > differently?
> > >
> > > E.g,. what should happen with "target sim" ?
> > 
> > I don't understand what you're asking.  "target sim" doesn't use
> > remote_filesystem_is_local, (to_filesystem_is_local for sim is the
> > default, tdefault_filesystem_is_local, which returns 1 always).
> 
> When you say:
> 
>  gdb_bfd_open contained a special case
>  to make vgdb work with "target:" sysroots, but the implementation
>  meant that GDB would fall back to the local filesystem if *any*
>  to_fileio_open method failed with ENOSYS for *any* reason.
> 
> I'd prefer to get an example target for one of those "if *any*
> to_fileio_open ... *any* reason".  I'd like to understand the
> real motivation for the change.  Because otherwise I get to
> wonder why would we handle any other target that goes through
> this path differently.

Ah, ok, I get what you're asking.

In what's upstream right now, the only path (I think) that you
can get to the point in gdb_bfd_open with the workaround is if
you're using a remote target that doesn't support file retrieval.
But, in the namespace-awareness series I posted, target_fileio_open
can fail with ENOSYS if setns is not available.  That's the reason
I made the change.

Thanks,
Gary

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