Re: [Xen-devel] libxl: spawning qemu while files are open

[Rob Hoes <Rob.Hoes@xxxxxxxxxx>]

> On Fri, 2013-10-18 at 15:26 +0000, Rob Hoes wrote:
> 
> > We could solve this by opening the suspend-image file in xenopsd using
> > the O_CLOEXEC flag, causing the file to be closed when executing qemu.
> > However, we are worried that this behaviour may still cause trouble in
> > multi-threaded programs such as xenopsd, unless all files it ever
> > opens are opened with O_CLOEXEC, which is easily forgotten.
> 
> I'm afraid this is exactly what you need to do.
> 
> libxl itself jumps through considerable hoops to ensure it does this itself,
> it's extra hard in a library... (have a look= for CLOEXEC in tools/libxl/*.h 
> for
> some details)

Alright, thanks. I'll look into that.

Cheers,
Rob

> xenopsd being the consuming app should have an easier time of it.
> 
> > Would it be possible for libxl to spawn qemu in such a way that it
> > won't inherit open files?
> 
> I don't think POSIX has any functionality which allows for that to be reliably
> implemented.
> 
> Ian.
> 

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