[Libguestfs] [PATCH v3 8/8] lib/canonical-name.c: Hide EINVAL error from underlying API call.

[Richard W.M. Jones]

On Fri, Oct 09, 2020 at 11:33:43AM +0100, Richard W.M. Jones wrote:
> 
> This is the patch I tested which works (on top of the
> patch posted):
> 
> diff --git a/lib/canonical-name.c b/lib/canonical-name.c
> index e0c7918b4..ae4def692 100644
> --- a/lib/canonical-name.c
> +++ b/lib/canonical-name.c
> @@ -53,8 +53,16 @@ guestfs_impl_canonical_device_name (guestfs_h *g, const char *device)
>       * BitLocker-encrypted volume, so simply return the original
>       * name in that case.
>       */
> -    if (ret == NULL && guestfs_last_errno (g) == EINVAL)
> -      ret = safe_strdup (g, device);
> +    if (ret == NULL) {
> +      if (guestfs_last_errno (g) == EINVAL)
> +        ret = safe_strdup (g, device);
> +      else
> +        /* Make sure the original error gets pushed through the
> +         * error handlers.
> +         */
> +        guestfs_int_error_errno (g, guestfs_last_errno (g),
> +                                 "%s", guestfs_last_error (g));
> +    }
>    }
>    else
>      ret = safe_strdup (g, device);
> 
> ---
> 
> Current upstream:
> 
> $ guestfish scratch 1M : run : canonical-device-name "/dev/dm-999"
> libguestfs: error: lvm_canonical_lv_name: stat: /dev/dm-999: No such file or directory
> /dev/dm-999           <-----
> 
> Patch posted without the above patch added:
> 
> $ ./run guestfish scratch 1M : run : canonical-device-name "/dev/dm-999"
> 
> (no output, but the command fails with exit code 1)
> 
> Patch posted + above patch:
> 
> $ ./run guestfish scratch 1M : run : canonical-device-name "/dev/dm-999"
> libguestfs: error: lvm_canonical_lv_name: stat: /dev/dm-999: No such file or directory

Actually I didn't notice this, but it improves on the current upstream
behaviour.

Current upstream calls the error handlers and returns a non-error
original string (see <----- line above) and exit code 0.  With the
patch we return an error.

Rich.

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