netListenIpPosix

fn netListenIpPosix(
    userdata: ?*anyopaque,
    address: *const IpAddress,
    options: IpAddress.ListenOptions,
) IpAddress.ListenError!net.Socket {
    if (!have_networking) return error.NetworkDown;
    const t: *Threaded = @ptrCast(@alignCast(userdata));
    _ = t;
    const family = posixAddressFamily(address);
    const socket_fd = try openSocketPosix(family, .{ .mode = options.mode, .protocol = options.protocol });
    errdefer closeFd(socket_fd);

    if (options.reuse_address) {
        try setSocketOptionPosix(socket_fd, posix.SOL.SOCKET, posix.SO.REUSEADDR, 1);
        if (@hasDecl(posix.SO, "REUSEPORT"))
            try setSocketOptionPosix(socket_fd, posix.SOL.SOCKET, posix.SO.REUSEPORT, 1);
    }

    var storage: PosixAddress = undefined;
    var addr_len = addressToPosix(address, &storage);
    try posixBind(socket_fd, &storage.any, addr_len);

    const syscall: Syscall = try .start();
    while (true) {
        switch (posix.errno(posix.system.listen(socket_fd, options.kernel_backlog))) {
            .SUCCESS => {
                syscall.finish();
                break;
            },
            .INTR => {
                try syscall.checkCancel();
                continue;
            },
            .ADDRINUSE => return syscall.fail(error.AddressInUse),
            .BADF => |err| return syscall.errnoBug(err), // File descriptor used after closed.
            else => |err| return syscall.unexpectedErrno(err),
        }
    }

    try posixGetSockName(socket_fd, &storage.any, &addr_len);
    return .{ .handle = socket_fd, .address = addressFromPosix(&storage) };
}