[Libguestfs] [nbdkit PATCH v2 1/3] server: Add nbdkit_stdio_safe

[Richard W.M. Jones]

On Tue, Apr 14, 2020 at 09:05:57AM -0500, Eric Blake wrote:
> On 4/14/20 2:47 AM, Richard W.M. Jones wrote:
> >On Mon, Apr 13, 2020 at 07:28:59PM -0500, Eric Blake wrote:
> >[...]
> >
> >This patch is fine and can be pushed if you want, but I've got some
> >small comments.
> >
> >>+If C<nbdkit_stdio_safe> returns true, the value of the configuration
> >>+parameter may be used to trigger reading additional data through stdin
> >>+(such as a password or inline script).
> >
> >I wonder if we want to say "returns 1" rather than true, to give
> >ourselves wiggle room in future in case we suddenly decided that we
> >needed this to return an error indication?  On the other hand, maybe
> >errors can never happen in any conceivable situation.
> 
> It might be possible to change the function to return -1 when called
> at the wrong time (at .get_ready or later).  As written, the patch
> merely documents that this function is not useful at that point.
> But for now, I didn't see the point in making that change, but
> merely leaving it for the future.

It's still wrong for the plugin to read from stdin or write to stdout
even after .get_ready, so AFAICT checking nbdkit_stdio_safe() is
reasonable [shouldn't return -1] after get_ready.

Anyway you decide what's best.  Patch series over all is fine.

Rich.

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