Expose address from SockAddr for unix domains

[sullivan-sean]

It would be nice to be able to access the path of a unix socket from SockAddr similar to vsock_address

socket2 is being considered as a backend for UDS on windows in mio/tokio (tokio-rs/mio#1610 (comment)) and, if used, would need to expose the address of unix sockets from SocketAddr to mirror the implementation of SocketAddr in mio for unix

[Thomasdezeeuw]

It would be nice to be able to access the path of a unix socket from SockAddr similar to vsock_address

Do you mean https://docs.rs/socket2/latest/socket2/struct.SockAddr.html#method.unix? I think we simply forgot to expose it in #249.

socket2 is being considered as a backend for UDS on windows in mio/tokio (tokio-rs/mio#1610 (comment)) and, if used, would need to expose the address of unix sockets from SocketAddr to mirror the implementation of SocketAddr in mio for unix

It's not ;)

[sullivan-sean]

I meant more going the other way from SockAddr -> Path. Right now the SockAddr struct has private fields and there are no methods for Unix sockets exposing the Path which means once you have a SockAddr object (e.g. as returned from accept) you cannot get the corresponding Path back out, or tell whether a SockAddr is an unnamed or abstract Unix socket (i.e. the SockAddr here can't provide this functionality https://github.com/tokio-rs/mio/blob/master/src/sys/unix/uds/socketaddr.rs#L76-L96)

[Thomasdezeeuw]

We could add SocketAddr::as_pathname() -> Option<Path>.

[sullivan-sean]

What is the desired behavior for abstract unix sockets where there is a name associated with the SockAddr struct but this name has no connection with filesystem pathnames? (https://manpages.ubuntu.com/manpages/trusty/man7/unix.7.html)

Unnamed unix sockets would presumably return None from as_pathname, and normal sockets would return a Path as expected.

[Thomasdezeeuw]

I think we can match the std::os::unix::net::SocketAddr type and match the is_unnamed, as_pathname and as_abstract_namespace functions.

[sullivan-sean]

Okay, I think I have a good understanding of the desired API then -- I can take a stab at this and open a PR?

[Thomasdezeeuw]

Okay, I think I have a good understanding of the desired API then -- I can take a stab at this and open a PR?

Sounds good.

[aviramha]

Hey, this seems inactive and we need it for metalbear-co/mirrord#1105 .
I read the comments and will follow the desired design.

[Thomasdezeeuw]

Hey, this seems inactive and we need it for metalbear-co/mirrord#1105 . I read the comments and will follow the desired design.

Pr would be welcome 👍