[Libguestfs] [PATCH] daemon: do not fail list-disk-labels w/o labels set

[Richard W.M. Jones]

On Wed, Mar 02, 2016 at 02:45:04PM +0100, Pino Toscano wrote:
> If there are no labels set for the disks, the directory with the
> symlinks will not even exists, causing list-disk-labels to fail with
> ENOENT.  In this situation, act as if the directory was there, but
> empty.
> ---
>  daemon/devsparts.c   |  7 +++++++
>  generator/actions.ml | 12 ++++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/daemon/devsparts.c b/daemon/devsparts.c
> index 7b92bf6..7c690f8 100644
> --- a/daemon/devsparts.c
> +++ b/daemon/devsparts.c
> @@ -316,6 +316,13 @@ do_list_disk_labels (void)
>  
>    dir = opendir (GUESTFSDIR);
>    if (!dir) {
> +    if (errno == ENOENT) {
> +      /* The directory does not exist, and usually this happens when
> +       * there are no labels set.  In this case, act as if the directory
> +       * was empty.
> +       */
> +      return empty_list ();
> +    }
>      reply_with_perror ("opendir: %s", GUESTFSDIR);
>      return NULL;
>    }
> diff --git a/generator/actions.ml b/generator/actions.ml
> index 9c34463..287d7f5 100644
> --- a/generator/actions.ml
> +++ b/generator/actions.ml
> @@ -11336,6 +11336,18 @@ silently create an ext2 filesystem instead." };
>      name = "list_disk_labels"; added = (1, 19, 49);
>      style = RHashtable "labels", [], [];
>      proc_nr = Some 369;
> +    tests = [
> +      (* The test disks have no labels, so we can be sure there are
> +       * no labels.  See in tests/disk-labels/ for tests checking
> +       * for actual disk labels.
> +       *
> +       * Also, we make use of the assumption that RHashtable is a
> +       * char*[] in C, so an empty hash has just a NULL element.
> +       *)
> +      InitScratchFS, Always, TestResult (
> +        [["list_disk_labels"]],
> +        "is_string_list (ret, 0)"), [];
> +    ];
>      shortdesc = "mapping of disk labels to devices";
>      longdesc = "\
>  If you add drives using the optional C<label> parameter
> -- 

ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html