heimdal headers ordering (gssapi/gssapi.h, crypto-headers.h)

[Andrew Bartlett]

Looks like it. 

https://salsa.debian.org/samba-team/samba/-/blob/mjt-4.16/debian/rules#L30

That would explain a lot of 'Debian only' issues, like the big rebuild.

Andrew,

On Mon, 2022-03-28 at 10:04 +0200, Stefan Metzmacher via samba-
technical wrote:
> Hi,
> 
> are your using 'waf build' directly? This that I saw the same
> problem in the past. Please use 'make' and 'make install',
> the difference is that it passes PYTHONHASHSEED=1, without that
> the order is random.
> 
> metze
> 
> Am 28.03.22 um 09:14 schrieb Michael Tokarev via samba-technical:
> > In the other email, we wrote:
> > 
> >  >> First, the includes.  For example, while compiling
> >  >> lib/krb5_wrap/gss_samba.c ,
> >  >> the include-path includes -Ithird_party/heimdal/lib
> >  >> -Ithird_party/heimdal/lib/gssapi .
> >  >>
> >  >> gss_samba.c #includes gss_samba.h which includes
> >  >> lib/replace/system/gssapi.h,
> >  >> which - based on HAVE_GSSAPI_GSSAPI_H, includes
> >  >> <gssapi/gssapi.h>.  The first
> >  >> include path which has gssapi/gssapi.h is
> > third_party/heimdal/lib,
> >  >> so we include
> >  >> third_party/heimdal/lib/gssapi/gssapi.h. But this is a simple
> >  >> dispatcher file, it merely includes <gssapi/gssapi.h>.
> >  >> Which, as we know already, is
> >  >> third_party/heimdal/lib/gssapi/gssapi.h. So we end up
> >  >>  without all the gssapi definitions altogether.
> >  >> The correct file to include for <gssapi/gssapi.h>
> >  >> is third_party/heimdal/lib/gssapi/gssapi/gssapi.h (note the
> > double,
> >  >> or even
> >  >> triple, gssapi in there) - so the _second_ -I path should be
> > used
> >  >> from the
> >  >> above.  This is quite messy and not really reliable.
> >  >
> >  > Again, like symbols, header include paths are dependent on the
> > 'deps='
> >  > of the subsystems.  So a subsystem is missing a dependency.  We
> > have
> >  > had reports (to Heimdal, frustratingly) about this, but someone
> > needs
> >  > to chase it down.
> >  >
> >  > See https://bugzilla.samba.org/show_bug.cgi?id=15033
> > 
> > Too bad I didn't know about this when chasing this issue here :)
> > But it is good anyway to know there's someone else who hit it too
> > ;)
> > LOL :)
> > 
> > Okay.
> > 
> > The thing here is with include path ordering. And with timing
> > issues,
> > it seems.
> > 
> > I have logs from two consequtive builds, one of which failed (bad),
> > and another succeeded (good) without any changes in between (the
> > same source, the same packages installed from debian since I
> > haven't
> > run apt update, - everything is the same).
> > 
> > We should list heimdal_build/include *before* heimdal/include in
> > all cases. Yet the order is random, non-deterministic:
> > 
> > --- good0    2022-03-28 09:59:07.502426113 +0300
> > +++ bad0    2022-03-28 09:59:01.606521064 +0300
> > @@ -2,0 +3 @@
> > +-Ithird_party/heimdal/lib/krb5
> > @@ -3,0 +5 @@
> > +-Ithird_party/heimdal/include
> > @@ -4,0 +7,2 @@
> > +-Ithird_party/heimdal/lib/roken
> > +-Ithird_party/heimdal_build/include
> > @@ -7 +10,0 @@
> > --Ithird_party/heimdal/lib/krb5
> > @@ -9 +11,0 @@
> > --Ithird_party/heimdal_build/include
> > @@ -12,4 +14,2 @@
> > --Ithird_party/heimdal/lib/roken
> > --Ithird_party/heimdal/include
> > --Ithird_party/heimdal/lib/hcrypto
> > --Ithird_party/heimdal/lib
> > +-Ithird_party/heimdal/lib/hcrypto/libtommath
> > +-Ithird_party/heimdal/lib/wind
> > @@ -20 +19,0 @@
> > --Ithird_party/heimdal/lib/hcrypto/libtommath
> > @@ -22 +21,2 @@
> > --Ithird_party/heimdal/lib/hdb
> > +-Ithird_party/heimdal/lib/hcrypto
> > +-Ithird_party/heimdal/lib
> > @@ -24 +24 @@
> > --Ithird_party/heimdal/lib/wind
> > +-Ithird_party/heimdal/lib/hdb
> > 
> > There, I took one command line (compiling source4/kdc/wdc-
> > samba4.c),
> > split it into separate lines, saved into two files, filtered
> > everything related to heimdal, and diffed.  In the bad case,
> > heimdal/include is moved before heimdal_build/include.
> > And this break stuff for the reasons already mentioned above.
> > 
> > So we do have obvious ordering instability.
> > 
> > Besides this, we have one more very annoying issue. Namely, it
> > looks like "next" waf steps always include all previous steps,
> > complete or in parts.  In particular, `waf install' *always*
> > rebuilds about 6k files even if nothing at all had changed
> > in between. While `waf build' builds only about 4k files.
> > 
> > Why it is relevant in this context.
> > 
> > In debian, waf configure step is done with -j1, to avoid
> > parallel/ordering issues.  However, waf build and waf install
> > are done with default parallelism. But since `waf install'
> > re-does some of `waf configure' steps, but this time with
> > parallelism, this may lead to different results with the
> > ordering as we see with heimdal includes.
> > 
> > So it looks like we have 2 or 3 separate issues here:
> > the always-rebuild and install-builds-more-than-build,
> > and include ordering depending on parallelism.
> > 
> > I'll try to figure out what's going on, but these things
> > definitely require good understanding of waf internals
> > and machinery.
> > 
> > The two build logs are available, just in case, at
> > http://www.corpit.ru/mjt/tmp/samba-heimdal-include-ordering.tar.gz
> > 
> > Thanks,
> > 
> > /mjt
> > 
> 
> 
-- 
Andrew Bartlett (he/him)       https://samba.org/~abartlet/
Samba Team Member (since 2001) https://samba.org
Samba Team Lead, Catalyst IT   https://catalyst.net.nz/services/samba

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