[ntp:questions] custom ntp PPS driver

folkert folkert at vanheusden.com
Mon Apr 19 13:45:26 UTC 2021


> He tells me that from what he can find, a shared memory interface
> between the source and ntpd is simpler to implement.  What we are
> unclear of at present is who "owns" the shared memory segment.  I
> would speculate that the sender should create and own the segment as
> the "server" of the data, and that ntpd creating and owning the
> segment it reads timestamp data from would be an anti-pattern.

ntpd creates the segment.
Anyone with enough rights can then write to it, if required.
The other way around may also work but make sure it has the correct
size and access rights.
Personally I would ntpd create it and then check yourself if at least
the size of it is what you expect.

Please note that I'm not an authoritative source. I did wrote a few
applictions that interface with ntpd that way though.


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