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

[Reino Wijnsma]

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