2013/12/31 Jean-Baptiste Rouault <jean-baptiste.rouault@xxxxxxxxxxx>: > On Monday 30 December 2013 11:26:08 Ryota Ozaki wrote: >> On Mon, Dec 30, 2013 at 5:55 PM, Jean-Baptiste Rouault >> >> <jean-baptiste.rouault@xxxxxxxxxxx> wrote: >> > On Sunday 29 December 2013 14:44:10 Ryota Ozaki wrote: >> >> On Wed, Dec 25, 2013 at 12:47 AM, Jean-Baptiste Rouault >> >> >> >> <jean-baptiste.rouault@xxxxxxxxxxx> wrote: >> >> > While working on adding virDomain*Stats support to the vbox driver, we >> >> > found bugs in the VirtualBox API C bindings. These bugs have been >> >> > fixed in versions 4.2.20 and 4.3.4. >> >> > However, the changes in the C bindings are incompatible with the >> >> > vbox_CAPI_v4_2.h and vbox_CAPI_v4_3.h files which are bundled in >> >> > libvirt source code. This is why the following patch adds >> >> > vbox_CAPI_v4_2_20.h and vbox_CAPI_v4_3_4.h. >> >> > >> >> > We tried to keep compatibility with older VirtualBox 4.2.x and 4.3.x >> >> > releases so we added a "SPECIAL_VERSION" identifier to conditionnaly >> >> > include the right header. I'm not really pleased with this >> >> > "SPECIAL_VERSION" identifier, maybe we could instead increase the >> >> > precision of "VBOX_API_VERSION", for example 4002 would become >> >> > 4002000. This would permit us to select the right header based on the >> >> > VBOX_API_VERSION only, what do you think ? >> >> >> >> Can we use VBOX_XPCOMC_VERSION instead of adding a new flag? >> >> The version has been bumped up when the incompatibility is introduced. >> >> >> >> ozaki-r >> > >> > The problem is that VBOX_XPCOMC_VERSION is defined in the vbox_CAPI_v*.h >> > headers and we need a flag to choose which header we have to include. >> >> Oops. You're right. >> >> Well, one other idea is to include each vbox_CAPI_X_Y.h in >> the corresponding vbox_VX_Y.c. That's rather straightforward >> for me than including vbox_CAPI_*.h in vbox_tmpl.c according to >> VBOX_API_VERSION. >> >> ozaki-r > > This would indeed solve the problem for header inclusion. But what about > future code using the new API ? Will it have to check both VBOX_API_VERSION > and VBOX_XPCOMC_VERSION ? > Wouldn't it be simpler if VBOX_API_VERSION was more precise ? e.g 4003004 Okay, so the actual underlying problem here is that libvirt assumes that VirtualBox API can only change between minor versions (4.2 -> 4.3), but we have a case here where it changed (or got fixed) between release version (4.2.19 -> 4.2.20). Using this new SPECIAL_VERSION define is the least invasive fix for the problem. The more correct solution would be to make VBOX_API_VERSION represent the full API version number, instead of just the major and minor part. This would fix the incorrect assumption in libvirt. -- Matthias Bolte http://photron.blogspot.com -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list