Re: [Linuxptp-users] PMC Without Root

[Martin P. <pec...@fe...>]

That's a misconception. The socket is read-only on the application 
level, i.e. you can't issue any SET commands via it. However, the socket 
special file itself has to be read-write, because pmc needs 
bidirectional communication with the running ptp4l instance. Make it rw 
and it should work. Or even beter, use /var/run/ptp4lro which already 
has these permissions.

Martin

Dne 3.10.2022 v 19:02 Rich Schmidt napsal(a):

> I find that I still have to sudo to run pmc -u,  even if I make the 
> server socket /var/run/ptp4l...  permissions rw-rw-r--
>
> Rich Schmidt
> Precise Time Dept
> US Naval Observatory
> Washington, DC
>
> On Mon, Oct 3, 2022 at 9:56 AM Martin Pecka <pec...@fe...> wrote:
>
>     Hi Jason, that's what the readonly UDS socket is for. With default
>     configuration and PTP4L master branch, this is how you can query
>     TIME_STATUS_NP without root:
>
>     pmc -u -s /var/run/ptp4lro -i /tmp/pmc.socket "GET TIME_STATUS_NP"
>
>     The key is to supply the "-s /var/run/ptp4lro" which points to the
>     read-only socket. You also need to pass "-i /tmp/pmc.socket" or
>     something similar - this points to the path where PMC should
>     create its own socket. By default, it is /var/run/pmc.$pid, but
>     that location is not writable for non-root users. So I just
>     usually point it to /tmp (this socket is practically useless).
>
>     Martin
>
>     --
>     Mgr. Martin Pecka, Ph.D.
>     Researcher at Vision for Robotics and Autonomous Systems group
>     Faculty of Electrical Engineering
>     Czech Technical University in Prague
>     Phone: +420 22435 7269
>
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>
> -- 
>
> /"We learn from history that we learn nothing from history." /
> *George Bernard Shaw
> *
> *
> *
> “The ideal subject of totalitarian rule is not the convinced Nazi or 
> the convinced communist, but people for whom the distinction between 
> fact and fiction . . . and the distinction between true and false 
> . . . no longer exist.” —Hanna Arendt, “The Origins of 
> Totalitarianism” (1951)


--
Mgr. Martin Pecka, Ph.D.
Researcher at Vision for Robotics and Autonomous Systems group
Faculty of Electrical Engineering
Czech Technical University in Prague
Phone: +420 22435 7269