Re: [PATCH] meson: Propagate gnutls dependency

[Daniel P . Berrangé]

On Sat, Jan 02, 2021 at 01:25:07PM +0000, Peter Maydell wrote:
> On Sat, 2 Jan 2021 at 12:54, Roman Bolshakov <r.bolshakov@yadro.com> wrote:
> >
> > crypto/tlscreds.h includes GnuTLS headers if CONFIG_GNUTLS is set, but
> > GNUTLS_CFLAGS, that describe include path, are not propagated
> > transitively to all users of crypto and build fails if GnuTLS headers
> > reside in non-standard directory (which is a case for homebrew on Apple
> > Silicon).
> >
> > Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
> 
> Ah, this is https://bugs.launchpad.net/qemu/+bug/1909256
> -- thanks for finding a fix.
> 
> > ---
> >  block/meson.build          | 2 +-
> >  io/meson.build             | 2 +-
> >  meson.build                | 5 +++--
> >  storage-daemon/meson.build | 2 +-
> >  tests/meson.build          | 6 +++---
> >  ui/meson.build             | 2 +-
> >  6 files changed, 10 insertions(+), 9 deletions(-)
> 
> > diff --git a/ui/meson.build b/ui/meson.build
> > index 013258a01c..e6655c94a6 100644
> > --- a/ui/meson.build
> > +++ b/ui/meson.build
> > @@ -29,7 +29,7 @@ vnc_ss.add(files(
> >    'vnc-ws.c',
> >    'vnc-jobs.c',
> >  ))
> > -vnc_ss.add(zlib, png, jpeg)
> > +vnc_ss.add(zlib, png, jpeg, gnutls)
> >  vnc_ss.add(when: sasl, if_true: files('vnc-auth-sasl.c'))
> >  softmmu_ss.add_all(when: vnc, if_true: vnc_ss)
> >  softmmu_ss.add(when: vnc, if_false: files('vnc-stubs.c'))
> 
> Question to Paolo -- it seems pretty fragile to have to explicitly
> list "these source files need these extra CFLAGS" in half a dozen
> meson.build files, because it's pretty non-obvious that adding
> eg '#include "block/nbd.h"' to a .c file means that you also
> need to update the meson.build file to say "and now it needs these
> extra CFLAGS". Isn't there some way we can just have the CFLAGS
> added more globally so that if we use gnutls.h directly or
> indirectly from more .c files in future it Just Works ?

The actual usage of gnutls should be confined to the crypto/ code.

The rest of QEMU should only ever be using QEMU's TLS abstractions
and not directly be tied to GNUTLS. So ideally the gnutls flags
should only ever be added in the crypto/meson.build, and anything
which depends on that should then get the flags indirectly.


Regards,
Daniel
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