Add Socket::passcred/set_passcred for working with SO_PASSCRED.

[tobz]

This PR adds the ability to get and set the value of SO_PASSCRED on sockets.

Theoretically, FreeBSD does support the equivalent behavior, but does so via differently named constants/values, so I've opted to constrain this implementation to Linux only for now.

[Thomasdezeeuw]

Any chance you can add a smoke test to this?

[tobz]

When you say smoke test, what are you thinking? Like an integration test that only runs on Linux and actually sets the option on a Unix domain socket?

[tobz]

Just went ahead and added a test which hopefully fits your definition of "smoke test."

[tobz]

Woops, thought I added a test but I had committed to the wrong branch.

Should be all set now.

[tobz]

@Thomasdezeeuw Small bump.

Not in a rush, but I have the feeling this might have fallen off your radar after the approval. 😄

[Thomasdezeeuw]

Not in a rush, but I have the feeling this might have fallen off your radar after the approval. 😄

Hadn't fallen off my radar, but $dayjob got busy, then my open source work is the first on the chopping block I'm afraid.

Test looks good, for future reference we have a little test! macro to help with this:

socket2/tests/socket.rs

Line 1326 in 21ba660

test!(nodelay, set_nodelay(true));

. But merging as is.

Thanks @tobz!

[tobz]

Doh! Sorry about the pushiness. Totally understand $dayjob cutting into open source time. 😓

Thanks again for approving/merging! Is there a general cadence you follow for cutting releases? I'm already using a Git ref at the moment, so I'm fine continuing to do so for a little while... but mostly curious. :)

[Thomasdezeeuw]

Doh! Sorry about the pushiness. Totally understand $dayjob cutting into open source time. 😓

👍

Thanks again for approving/merging! Is there a general cadence you follow for cutting releases? I'm already using a Git ref at the moment, so I'm fine continuing to do so for a little while... but mostly curious. :)

Not really, I mostly make releases on request. We don't see too many changes