I've done things before where you shim in a library (using LD_PRELOAD) between the executable and the C standard library, and blacklist function calls which are

I've done things before where you shim in a library (using LD_PRELOAD) between the executable and the C standard library, and blacklist function calls which are potentially blocking, (abort if they get called in the wrong context). It's usually sufficient to do this in testing, and then have as is, in production.