Initial prefixer tool

[tedjpoole]

Initial implementation of the header prefixer tool.

Signed-off-by: Ted Poole tpoole@redhat.com

[pfl]

Prefixer looks good! Next step is to get the linking part done and then an example file to use the prefixed functions, right?

[tedjpoole]

For each <function> declared in the source OpenSSL headers, the prefixer now:

• Renames it to <prefix>_<function>
• Generates a function pointer typedef called <prefix>_<function>_t
• Generates a member in the <prefix>_functions struct, called <prefix>_<function> (of type <prefix>_<function>_t)
• Generates the dlopen()/dlsym() code to initialise the function pointer in the <prefix>_functions struct.
• Generates an implementation for <prefix>_<function> which calls through to the corresponding function pointer.

The RAND_bytes() function has been modified to #include the prefixed "ossl/openssl/rand.h" header, and call onto the prefixed ossl_RAND_bytes() wrapper function., and the test_rand binary successfully links and runs.

[pfl]

LGTM! Compiling test_rand works fine when openssl is downloaded. But when I have openssl version 3.0.7 installed in the OS, the prefixer generates its files, but then compilation fails with

[ 21%] Building C object CMakeFiles/bssl-compat.dir/source/rand.c.o
In file included from /home/pflykt/projects/envoy-openssl/bssl-compat/source/rand.c:20:
In file included from /home/pflykt/projects/envoy-openssl/bssl-compat/build/include/ossl/openssl/rand.h:14:
/home/pflykt/projects/envoy-openssl/bssl-compat/build/include/ossl/openssl/macros.h:139:4: error: "The requested API level higher than the configured API compatibility level"

[tedjpoole]

Thanks for spotting that @pfl. I still have 1.1.1 on my host so I hadn't tried OpenSSL 3 yet! I'll take a look

[tedjpoole]

OpenSSL 3.0 will be addressed at a later date