[systemd-devel] [PATCH] Circumvent autofs_v5_packet_union size bug

[Thomas Meyer]

Am Freitag, den 11.11.2011, 14:33 +0100 schrieb Kay Sievers:
> On Tue, Sep 20, 2011 at 14:26, Kay Sievers <kay.sievers at vrfy.org> wrote:
> > On Tue, Sep 20, 2011 at 12:58, Lennart Poettering
> > <lennart at poettering.net> wrote:
> >> On Tue, 20.09.11 11:36, Ian Kent (raven at themaw.net) wrote:
> >>
> >>> > This is a bug in the kernel, and it should be fixed in the kernel (which
> >>> > would mean the kernel folks have to define a new version of this
> >>> > struct/ioctl which fixes this). If that's defined we can then add
> >>> > support for this into systemd. Could you file a bug about this please on
> >>> > the kernel bugzilla? (please cc me, or post the url here!)
> >>>
> >>> Yes, it is a mistake that I made but it is a bad idea to change
> >>> something that will cause widespread failure of existing binaries and
> >>> that's why the discrepancy persists and will continue to do so.
> >>
> >> I am not expecting this to be changed in the kernel. Instead I expect
> >> that the kernel API is extended with a correct version of the same data
> >> structure. If the kernel broke it the kernel should fix it.
> >>
> >>> I chose to compensate for it in user space and to advise anyone that
> >>> encountered the problem on how to handle it and I have had no reports of
> >>> problems in autofs since I added the size calculation (which was a long
> >>> time ago now).
> >>
> >> Well, it's a workaround in userspace. Fix the kernel. Add a second union
> >> or something which can be used by newer clients.
> >>
> >>> > I am sorry but I am pretty sure I want to keep the compat kludges for
> >>> > broken things in systemd at a minimum, adding such a work around looks
> >>> > like the wrong way to me. We generally try to fix problems where they
> >>> > are these days, not where we notice them.
> >>>
> >>> Sure, it is unfortunate but, as far as the autofs kernel module is
> >>> concerned the decision about this was made a long time ago and, yes it
> >>> isn't what we want but the breakage it would have caused then and the
> >>> breakage it would cause now is too great.
> >>
> >> Adding a corrected version will not break anything. This is not about
> >> replacing the current borked interface, but simply by adding a fixed
> >> version that we can use from userspace without ugly compat glue.
> >>
> >> Fix the problems where they are, don't work around them where they aren't.
> >
> > I can only second that.
> >
> > Please add a new definition, leave the old around, and do not require
> > userspace to do wild things, like compare static lists of
> > architectures to work around things that can be expected to just work.
> 
> Ian, is this fixed in the meantime? If not, mind fixing the kernel bug
> and introduce an non-broken version of the kernel interface.
> 
> We like to have this fixed in systemd, but are still reluctant to
> compile lists of static 32 vs. 64 architecture bit matches in init.

Hi,

just did this quick hack. It compiles, but I didn't test it: