[FFmpeg-devel] [PATCH] libavformat: add mbedTLS based TLS

[Ricardo Constantino]

On 26 May 2018 at 19:42, Reino Wijnsma <rwijnsma at xs4all.nl> wrote:

> On 23-5-2018 2:11, Reino Wijnsma <rwijnsma at xs4all.nl> wrote:
> > On 22-4-2018 14:47, Thomas Volkert <silvo at gmx.net> wrote:
> >> +enabled mbedtls           && { check_pkg_config mbedtls mbedtls
> mbedtls/x509_crt.h mbedtls_x509_crt_init ||
> >> +                               check_pkg_config mbedtls mbedtls
> mbedtls/ssl.h mbedtls_ssl_init ||
> >> +                               check_lib mbedtls mbedtls/ssl.h
> mbedtls_ssl_init -lmbedtls ||
> >> +                               die "ERROR: mbedTLS not found"; }
> > Now that James Almer has pushed this patch I decided to have a look as
> well. I wanted to see if mbedtls would work for me too.
> > I haven't made a FFmpeg build yet to test, because the excerpt above (in
> 'configure') doesn't look right and configuring FFmpeg returns lots of
> undefined references.
> >
> > First of all, there's no pkg-config file at all. Almost 3 years ago
> someone requested it (https://github.com/ARMmbed/mbedtls/issues/228), but
> as far as I can see it hasn't been implemented yet. So, I really don't
> understand why you added the 2 check_pkg_config lines.
> > Secondly, the check_lib line also needs -lmbedx509 and -lmbedcrypto!
> >
> > -lmbedtls, the most important one obviously, prevents a "undefined
> reference to `mbedtls_ssl_init'", but...
> > -lmbedx509 is also needed, because otherwise you'd get "undefined
> reference to `mbedtls_x509_crt_init'" and several "undefined reference to
> `mbedtls_x509_crt_[...]'".
> > -lmbedcrypto is also needed, because otherwise you'd get LOTS of
> "undefined reference to `mbedtls_[...]'"; from "undefined reference to
> `mbedtls_sha256_init'" to "undefined reference to `mbedtls_pem_init'"!
> >
> > The following patch works for me:
> >
> > diff --git a/configure b/configure
> > index 09ff0c5..6014e03 100755
> > --- a/configure
> > +++ b/configure
> > @@ -6111,9 +6111,7 @@ enabled libzvbi           && require_pkg_config
> libzvbi zvbi-0.2 libzvbi.h vbi_d
> >                               { test_cpp_condition libzvbi.h
> "VBI_VERSION_MAJOR > 0 || VBI_VERSION_MINOR > 2 || VBI_VERSION_MINOR == 2
> && VBI_VERSION_MICRO >= 28" ||
> >                                 enabled gpl || die "ERROR: libzvbi
> requires version 0.2.28 or --enable-gpl."; }
> >  enabled libxml2           && require_pkg_config libxml2 libxml-2.0
> libxml2/libxml/xmlversion.h xmlCheckVersion
> > -enabled mbedtls           && { check_pkg_config mbedtls mbedtls
> mbedtls/x509_crt.h mbedtls_x509_crt_init ||
> > -                               check_pkg_config mbedtls mbedtls
> mbedtls/ssl.h mbedtls_ssl_init ||
> > -                               check_lib mbedtls mbedtls/ssl.h
> mbedtls_ssl_init -lmbedtls ||
> > +enabled mbedtls           && { check_lib mbedtls mbedtls/ssl.h
> mbedtls_ssl_init -lmbedtls -lmbedx509 -lmbedcrypto ||
> >                                 die "ERROR: mbedTLS not found"; }
> >  enabled mediacodec        && { enabled jni || die "ERROR: mediacodec
> requires --enable-jni"; }
> >  enabled mmal              && { check_lib mmal interface/mmal/mmal.h
> mmal_port_connect -lmmal_core -lmmal_util -lmmal_vc_client -lbcm_host ||
> >
> > Also note that the order is important, because with -lmbedtls
> -lmbedcrypto -lmbedx509 you'd get: "undefined reference to
> `mbedtls_pk_parse_subpubkey'" and "undefined reference to
> `mbedtls_pk_load_file'".
> >
> > (If it matters, I'm cross-compiling on Windows using Cygwin, MinGW and
> GCC).
> >
> > -- Reino
> *Ping* at Thomas Volkert, or anyone else responsible for this.
>


FWIW, curl also adds all three libs, not just -lmbedtls, in their
configure. Maybe shared builds only need the one, but static do require all
three.

No opinion on removing the check_pkg_config lines since they have one
possibly coming up soon, from looking at the PRs.