Unix socket support in the standard library

[sfackler]

Rendered

[alexcrichton]

Perhaps another unresolved question for now could be whether Windows named pipes should be added in parallel? Or something along the lines of if we should hold off on stabilization until there's a suitable Windows alternative as well.

[sfackler]

I don't think that blocking this feature on named pipes makes a ton of sense. Named pipes do not appear to be used heavily in the Rust ecosystem, and I don't really want us to get into a habit of wanting to add platform specific feature X to the standard library and then hunting for a roughly comparable other-platform specific feature Y to implement along side it for "symmetry".

[alexcrichton]

Hm ok, but I do also want to not tip the scales too far in favor of Unix as there are lots of abstractions on Windows we could reasonably provide (e.g. named pipes, IOCP bindings, etc). While crates today may not use these much it may just be because the Windows community is a little smaller.

These are mostly just musings, though, I'd be ok if the RFC doesn't explicitly mention named pipes.

[DemiMarie]

SOCK_DGRAM Unix sockets are reliable.

[alexcrichton]

🔔 This RFC is now entering its week-long final comment period 🔔

[alexcrichton]

Also from discussion in triage yesterday, the libs team concluded that a good way forward for now with abstract sockets is to do something like:

• Validate no nul bytes are found in strings
• Perhaps eventually add a linux-specific extension trait to manage abstract sockets.

It at least errs on the side of being conservative for now!

[sfackler]

Updated to disallow use of the abstract namespace.

[gkoz]

Shouldn't there be a way to set permissions on the socket before starting to listen to it?

[sfackler]

What libc API would that use? According to the man page, the socket will inherit the permissions of the directory it's defined in on Linux, but filesystem permissions are ignored on BSD: http://man7.org/linux/man-pages/man7/unix.7.html#NOTES

[gkoz]

I had chmod in mind ;) Okay, while I doubt any modern BSDs ignore "file" permissions I totally missed that the portable way is to rely on directory-level permissions.

[alexcrichton]

The libs team discussed this RFC during triage yesterday, an the decision was to merge. This was the original intention for how Unix sockets would reenter the standard library and the unix-socket crate is doing well enough that moving it in almost wholesale seems good at this time (it's quickly becoming a vetted API).

Thanks again for the RFC @sfackler!

Tracking issue: rust-lang/rust#32312

[alexcrichton]

Ah, also, the initial implementation: rust-lang/rust#32302