[libvirt] wireshark compilation warning

[Daniel P. Berrange]

On Wed, Jul 20, 2016 at 10:27:36AM -0400, Cole Robinson wrote:
> I'm seeing this compilation warning on Fedora 24, with
> wireshark-devel-2.1.0-3.fc24.x86_64 which has the header file fix that was
> previously breaking compilation:
> 
>   CC       wireshark/src/wireshark_src_libvirt_la-packet-libvirt.lo
>   CC       wireshark/src/wireshark_src_libvirt_la-plugin.lo
>   CCLD     nss/libnss_libvirt.la
> wireshark/src/packet-libvirt.c: In function 'proto_reg_handoff_libvirt':
> wireshark/src/packet-libvirt.c:548:46: warning: passing argument 1 of
> 'create_dissector_handle' from incompatible pointer type
> [-Wincompatible-pointer-types]
>      libvirt_handle = create_dissector_handle(dissect_libvirt, proto_libvirt);
>                                               ^~~~~~~~~~~~~~~
> In file included from wireshark/src/packet-libvirt.c:28:0:
> /usr/include/wireshark/epan/packet.h:525:68: note: expected 'dissector_t {aka
> int (*)(struct tvbuff *, struct _packet_info *, struct _proto_node *, void
> *)}' but argument is of type 'void (*)(tvbuff_t *, packet_info *, proto_tree
> *) {aka void (*)(struct tvbuff *, struct _packet_info *, struct _proto_node *)}'
>  WS_DLL_PUBLIC dissector_handle_t create_dissector_handle(dissector_t dissector,
> 
> 
> I can't even find the definition of dissect_libvirt so I assume there's some
> weird magic going on here...

This is all in wireshark auto-generated code. In tools/wireshark/src it
has auto-generated packet-libvirt.c containing

static void
dissect_libvirt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
...
}


The dissector_t type though is defined as

typedef int (*dissector_t)(tvbuff_t *, packet_info *, proto_tree *, void *);


So there's the wrong return type and a missing arg. Seems wireshark
code generator is simply broken.

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|