[Libguestfs] Name resolution not working inside virt-customize

[Richard W.M. Jones]

On Wed, Mar 11, 2015 at 09:29:29AM -0400, Lee Revell wrote:
> On 03/10/2015 05:12 PM, Richard W.M. Jones wrote:
> >Just for comparison, libguestfs 1.29.29 on Fedora host, plus
> >virt-builder, with a Fedora guest does this:
> 
> Hmm, something weird is going in with the output of virt-customize.

What actually happens is that we download the log file using the
guestfs_download API:

  https://github.com/libguestfs/libguestfs/blob/master/customize/customize_run.ml#L44

The API opens [in this instance] /dev/stderr with O_TRUNC:

  https://github.com/libguestfs/libguestfs/blob/master/src/proto.c#L752

So if you redirect stderr to a file, then the file gets truncated.

A quick fix is to use `tee' (or another program) in the redirection,
since a pipe ignores truncations.

The real fix is to modify the guestfs_download API to allow the
truncation behaviour to be optional.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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