[Libguestfs] [PATCH] daemon: parted: Always use -s option even with -m.

[Richard W.M. Jones]

On Wed, Jun 17, 2015 at 07:50:11PM +0100, Richard W.M. Jones wrote:
> On Wed, Jun 17, 2015 at 05:23:53PM +0100, Richard W.M. Jones wrote:
> > See: https://bugzilla.redhat.com/show_bug.cgi?id=1232241#c3
> > ---
> >  daemon/parted.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/daemon/parted.c b/daemon/parted.c
> > index a36e4e7..59760b4 100644
> > --- a/daemon/parted.c
> > +++ b/daemon/parted.c
> > @@ -356,7 +356,7 @@ print_partition_table (const char *device,
> >    int r;
> >  
> >    if (PARTED_OPT_HAS_M == parted_has_m_opt)
> > -    r = command (&out, &err, str_parted, "-m", "--", device,
> > +    r = command (&out, &err, str_parted, "-m", "-s", "--", device,
> >                   "unit", "b",
> >                   "print", NULL);
> 
> This breaks virt-alignment-scan.  Not sure why yet.

It happens because adding -s changes the exit code of parted, so a
previously hidden error is exposed, and that in turn breaks the
part-list command when used on a blank disk.

$ parted -m -s -- tests/guests/blank-disk.img unit b print
Error: /home/rjones/d/libguestfs/tests/guests/blank-disk.img: unrecognised disk label
BYT;
/home/rjones/d/libguestfs/tests/guests/blank-disk.img:104857600B:file:512:512:unknown::;
$ echo $?
1

$ parted -m -- tests/guests/blank-disk.img unit b print
WARNING: You are not superuser.  Watch out for permissions.
Error: /home/rjones/d/libguestfs/tests/guests/blank-disk.img: unrecognised disk
label
BYT;                                                                      
/home/rjones/d/libguestfs/tests/guests/blank-disk.img:104857600B:file:512:512:unknown::;
$ echo $?
0

This is why I hate parted.

Anyway, I will post a v2 patch with this problem fixed.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v