Hi

On Mon, May 23, 2022 at 7:56 PM Daniel P. Berrangé <berrange@redhat.com>
wrote:

> On Mon, May 23, 2022 at 07:30:42PM +0200, Marc-André Lureau wrote:
> > Hi
> >
> > On Mon, May 23, 2022 at 2:43 PM Daniel P. Berrangé <berrange@redhat.com>
> > wrote:
> >
> > > On Fri, May 13, 2022 at 08:08:11PM +0200, marcandre.lureau@redhat.com
> > > wrote:
> > > > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> > > >
> > > > Used in the next patch, to simplify qga code.
> > > >
> > > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > > > ---
> > > >  include/qemu/osdep.h |  1 +
> > > >  util/osdep.c         | 10 ++++++++--
> > > >  2 files changed, 9 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> > > > index 67cc465416..64f51cfb7a 100644
> > > > --- a/include/qemu/osdep.h
> > > > +++ b/include/qemu/osdep.h
> > > > @@ -489,6 +489,7 @@ void sigaction_invoke(struct sigaction *action,
> > > >   */
> > > >  int qemu_open_old(const char *name, int flags, ...);
> > > >  int qemu_open(const char *name, int flags, Error **errp);
> > > > +int qemu_open_cloexec(const char *name, int flags, mode_t mode,
> Error
> > > **errp);
> > >
> > > I don't think we should be exporting this - it is just a variant of the
> > > 'qemu_open_old' method that we wanted callers to stop using in favour
> > > of explicitly deciding between 'qemu_open' and 'qemu_create'.
> > >
> >
> >
> > qemu_open() has "/dev/fdset" handling, which qemu-ga and other tools
> don't
> > need.
>
> Right, but exporting this as 'qemu_open_cloexec' is going to mislead
> people into thinking it is a better version of 'qemu_open'. This will
> cause us to loose support for /dev/fdset in places where we actually
> need it.
>

> It is pretty harmless to have /dev/fdset there, even if the tool does
> not need it - that's been the case with many QEMU tools for many years.
> If we think it is actually a real problem though, we should just have
> a way to toggle it on/off from the existing APIs.
>
>
It's a bit problematic to make qemu-ga standalone, and have a common shared
subproject/library.

Maybe introduce a callback for QEMU/QMP "/dev/fdset" handling ? any better
idea ?

eg put  'bool allow_fdset = true"   in softmmu/vl.c, and
> 'bool allow_fdset = false' in stubs/open.c, and then make
> qemu_open_internal conditionalize itself on this global
> variable, so only the system emulators get fdset support
> activated.
>
> With regards,
> Daniel
> --
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>

-- 
Marc-André Lureau