If you're able to write a robust shared ring buffer in C, you should be able to do the exact same implementation in unsafe Rust using raw pointers, declare it as Sync and use it from safe Rust with no issue. Or am I missing something ?

Or, if you're like me and not confident enough to do this, you could check on crates.io[1] to see if no available lib already does what you need. In which case you basically have it for free.

[1] https://crates.io/keywords/ring-buffer