Debian and Hyper-V VM drivers

[Ben Hutchings]

On Sun, 2012-06-10 at 16:18 +0100, Ben Hutchings wrote:
[...]
> The problems I've found so far (by inspection):
> 
> 1. The daemon leaks a file handle on every configuration update.

Fixed by the attached 'tools-hv-fix-file-handle-leak.patch'

> 2. It doesn't check for write failures, and it doesn't check correctly
> for read failures.

Fixed by the attached 'tools-hv-check-for-read-write-errors.patch'.

> 3. It stores state in /var/opt/hyperv, which is only appropriate for
> programs installed in /opt.  This should be configurable at build time.

Changed by the attached 'tools-hv-fix-var-subdirectory.patch', but not
made configurable (because I don't see the need).

> 4. The protocol between driver and daemon does not appear to be stable.
> Do they need to be upgraded in lockstep, or will either be backward-
> compatible with older versions of the other?

Please answer this.

> 5. The daemon uses incorrect types for strings, resulting in a large
> number of compiler warnings when building with 'gcc -Wall' (which is
> generally good practice).

Fixed by the attached 'tools-hv-fix-string-types.patch'.

> 6. When and how should the daemon be started?  There is no init script
> (or upstart job) provided, either in the linux source or the Ubuntu
> packaging.

I downloaded the Linux Integration Services from
<https://www.microsoft.com/en-us/download/details.aspx?id=28188> and
found an init script in that.

I also found <https://launchpad.net/ubuntu/+source/hv-kvp-daemon-init>,
but this is not useful for Debian (we don't use upstart by default).

> [Less important:]
> 7. There is no Makefile, and the one added by Ubuntu is incorrect (make
> install doesn't respect $(DESTDIR)).

Still TBD.

> 8. The daemon doesn't detect or parse the OS release correctly (even, so
> far as I can see, on the distributions which it has explicit support
> for).

Fixed by the attached 'tools-hv-parse-etc-os-release.patch'.

> 9. Permissions of S_IRUSR | S_IWUSR | S_IROTH (octal 604) make no sense.

Fixed by the attached 'tools-hv-fix-permissions.patch'.

> According to the manual page, 'This pairing allows the Hyper-V host to
> pass configuration information (such as IP addresses) to the guest...'
> but I don't see any sign that the daemon actually applies any
> configuration.  Is this intended to be done by some other 'guest tool'
> distributed by Microsoft?  Is that the reason for (3) and/or (6)?

I'm assuming this is not the case, since the package I downloaded from
MS did not contain any extra tools.  So the manual page should probably
be fixed too.

I have *not* tested these changes beyond actually compiling, as I don't
have a Hyper-V installation on which to test.  Would you be able to test
a binary package, or provide remote access to a suitable VM?

It is still important that I get an answer to question 4.

Ben.

-- 
Ben Hutchings
I say we take off; nuke the site from orbit.  It's the only way to be sure.
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