[Xen-devel] Re: POC: ncurses in stubdom

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Ferenc Wagner, le Tue 28 Apr 2009 21:56:07 +0200, a écrit :
> >>  * access() is also blatantly stubbed, as it's pointless in stub
> >>  domains anyway.
> >
> > No it's not.  It's just a matter of adding the interface to fsio.
> 
> I meant that it makes a distinction on real vs effective UID/GID,
> which isn't an issue in the single-user stubdom environment.
> Otherwise, I wouldn't do anything but opened races...
> 
> > Trying to open/close the file and returning appropriate errors should
> > already be enough to test the R_OK and W_OK cases,
> 
> Only if euid=ruid, which is always the case in stubdom, isn't it?

Yes.

> But then trying the operation itself provides the exact same
> diagnostics.  This is what I mean by "pointless".

Ok, but applications could still be upset to see access() work and not
open(), or vice-versa.

> #if defined(HAVE_POSIX_MEMALIGN)
>   if (posix_memalign (&p, align, size) != 0)
>     p = 0;
> #elif defined(HAVE_MEMALIGN)
>   p = memalign (align, size);

Errr, so grub2 doesn't unconditionally use posix_memalign.  How did
grub2 detect HAVE_POSIX_MEMALIGN?  Adding posix_memalign as a proper
function shouldn't be hard, though (and could be submitted upstream).

Samuel

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