[ntp:questions] ntpdate.c unsafe buffer write
david at ex.djwhome.demon.co.uk.invalid
Sun Feb 10 21:49:26 UTC 2008
Harlan Stenn wrote:
> Why would ntpd be exiting during a warm start?
Because we are discussing using it with the -q option. If you just use
-g, it will take a lot longer to converge within a few milliseconds, as
it will not slew at the maximum rate. If you use -q, you need to force
a step if you want fast convergence.
> For the case I'm describing the startup script sequence is to fire up 'ntpd
> -g' early. If there are applications that need the system clock to be
> on-track stable (even if a wiggle is being dealt with), that's 'state 4',
> and running 'ntp-wait' before starting those services is, to the best of my
> knowledge, all that is required.
State 4 means within 128ms and using the normal control loop, which has
a time constant of around an hour.
> David> For a cold start, it won't reach state 4 for a further 900 seconds
> David> after first priming the clock filter.
> If the system has a good drift file, I disagree with you.
The definition of cold start is that there is no drift file.
> And what is the big deal with using different config files? The config file
> mechanism has "include" capability so it is trivial to to easily maintain
> common 'base' configuration with customizations for separate start/run
You are now talking about using -q. The difficulty is that people have
enough trouble getting the run phase config file right.
> But the bigger problem is why are you insisting on separate start/run
> phases? This has not been "best practice" for quite a while, and if you
> insist on using this method you will be running in to the exact problems you
> are describing.
> No, the best advice is to understand why you have been using ntpdate -b so
> far and understand the pros/cons of the new choices.
We are talking about system managers and package creators, neither of
which have much time to study the details.
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