[Libguestfs] [PATCH 1/2] mllib: add normalize_arch helper

[Richard W.M. Jones]

On Tue, Aug 11, 2015 at 03:45:11PM +0200, Pino Toscano wrote:
> Small helper to normalize an architecture string, so it is easier to
> compare them and check for compatibilities.
> 
> Make use of it in guest_arch_compatible, simplifying it.

Have a look at:
8864c47b94cf44ac2d0d8d4b5019073ad1da121b

>  mllib/common_utils.ml  | 12 ++++++++++--
>  mllib/common_utils.mli |  5 +++++
>  2 files changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
> index f9e8996..ca6d470 100644
> --- a/mllib/common_utils.ml
> +++ b/mllib/common_utils.ml
> @@ -730,13 +730,21 @@ let rec mkdir_p path permissions =
>      mkdir_p (Filename.dirname path) permissions;
>      Unix.mkdir path permissions
>  
> +let normalize_arch = function
> +  | "i386" | "i486" | "i586" | "i686" -> "i386"
> +  | "amd64" | "x86_64" -> "x86_64"

Commit 8864c47b had "x64" also (added by you in b1cf6246).

> +  | "powerpc" | "ppc" -> "ppc"
> +  | arch -> arch
> +
>  (* Are guest arch and host_cpu compatible, in terms of being able
>   * to run commands in the libguestfs appliance?
>   *)
>  let guest_arch_compatible guest_arch =
> -  match Config.host_cpu, guest_arch with
> +  let own = normalize_arch Config.host_cpu in
> +  let guest_arch = normalize_arch guest_arch in
> +  match own, guest_arch with
>    | x, y when x = y -> true
> -  | "x86_64", ("i386"|"i486"|"i586"|"i686") -> true
> +  | "x86_64", "i386" -> true
>    | _ -> false

Commit 8864c47b may have got this wrong.  You cannot, for example, run
'dnf install' in an i686 guest, as it tries to install x86_64
packages.  Try this command for example:

  virt-builder --arch i686 fedora-22 --install net-tools

There doesn't seem to be a way to force dnf to use another basearch.

I wonder also if instead of a normalize function, we want a compare
function.  Or maybe we want both?  A compare function is safer, maybe,
since it preserves the actual arch string.

Rich.

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