On Fri, Sep 20, 2019 at 11:09:53AM -0700, Linus Torvalds wrote: (...) > So: > > - GRND_INSECURE is (GRND_EXPLICIT | GRND_NONBLOCK) > > As in "I explicitly ask you not to just not ever block": urandom > > - GRND_SECURE_BLOCKING is (GRND_EXPLICIT | GRND_RANDOM) > > As in "I explicitly ask you for those secure random numbers" > > - GRND_SECURE_NONBLOCKING is (GRND_EXPLICIT | GRND_RANDOM | GRND_NONBLOCK) > > As in "I want explicitly secure random numbers, but return -EAGAIN > if that would block". > > Which are the three sane behaviors (that last one is useful for the "I > can try to generate entropy if you don't have any" case. I'm not sure > anybody will do it, but it definitely conceptually makes sense). > > And I agree that your naming is better. > > I had it as just "GRND_SECURE" for the blocking version, and > "GRND_SECURE | GRND_NONBLOCK" for the "secure but return EAGAIN if you > would need to block for entropy" version. > > But explicitly stating the blockingness in the name makes it clearer > to the people who just want GRND_INSECURE, and makes them realize that > they don't want the blocking version. I really like it this way. Explicit and full control for the application plus reasonable backwards compatibility, it sounds pretty good. Willy