[Fedora-packaging] systemd and privileged ports

[T.C. Hollingsworth]

On Thu, Jul 18, 2013 at 2:21 AM, Daniel Pocock <daniel at pocock.com.au> wrote:
>
> Hi,
>
> In my blog the other day, I noted that upcoming versions of my package
> will be able to bind on port 443 (to provide TLS protected SIP over
> WebSockets)
>
> I've made upstream changes so the process can be started as root and
> drop privileges after binding.
>
> Somebody commented that I can use systemd to create the socket though.
> Looking at the man pages very briefly, I have the impression that this
> is only relevant to processes that spawn a new process to handle each
> client and that processes handling multiple clients can't take advantage
> of this.
>
> Is that correct?  Or can systemd pass in a listening socket that has not
> received any connection yet?

systemd can do the inetd-style activation you speak of, pass you a
listening socket when starting on boot, or even wait until a
connection is initiated before starting you.

These explain what you need to do to implement the latter two in a daemon:
http://0pointer.de/blog/projects/socket-activation.html
http://0pointer.de/blog/projects/socket-activation2.html

Or if inetd is what you really want:
http://0pointer.de/blog/projects/inetd.html

-T.C.