MacOS: can't access local_socket created in a process running as root from a non-root process.

[radiohertz]

The listener is created by a process running as root and the client is a non-root process.

The client fails to connect with

called `Result::unwrap()` on an `Err` value: Os { code: 2, kind: NotFound, message: "No such file or directory" }

My only guess is that the client and server are generating two different names.
The server creates a socket in /tmp/sock and when i try to connect to the server with the same name sock, it can't find the file.

Example

/// src/main.rs

use std::io::Read;

use interprocess::{
    local_socket::{traits::Listener, ListenerOptions, ToNsName},
    os::unix::local_socket::SpecialDirUdSocket,
};

fn main() {
    let listener = ListenerOptions::new()
        .name("test".to_ns_name::<SpecialDirUdSocket>().unwrap())
        .create_sync()
        .unwrap();

    loop {
        let mut stream = listener.accept().unwrap();
        println!("got a connection");
        let mut buf = [0; 1024];
        if let Err(e) = stream.read(&mut buf) {
            println!("{e}");
        }
    }
}

/// examples/client.rs

use interprocess::{
    local_socket::{self, traits::Stream, ToNsName},
    os::unix::local_socket::SpecialDirUdSocket,
};

fn main() {
    let stream =
        local_socket::Stream::connect("test".to_ns_name::<SpecialDirUdSocket>().unwrap()).unwrap();
}

[kotauskas]

My only guess is that the client and server are generating two different names.

That is not possible.

If you get a directory listing for /tmp from the command line (ls -lh /tmp), does it contain the socket file? If not, does it contain it if ls is run as root?

[kotauskas]

What are the permissions of /tmp's destination (it's reportedly a symlink on macOS)? The OS may have screwed them up for one reason or another.

[radiohertz]

it's lrwxr-xr-x@ and it does symlink to /private/tmp.

[kotauskas]

In that case, you should sudo chmod 1777 /tmp and the same for /private/tmp, as those are the standard permissions for /tmp, and are expected by portable software written for Unix-like systems.

[radiohertz]

I did change the perms on the directories and it's still No such file or directory and i'm just tired at this point. Anyway, thanks for helping out.

[kotauskas]

You're welcome!

I'm bothered by macOS's odd behavior here. SpecialDirUdSocket isn't supposed to fail like this, as it expects the directory it points to to be world-accessible, ideally with the sticky bit (so 1777). While I can't easily provide a better solution without introducing a breaking change, I'll try my best to document this issue in an approachable way.