ntpd applet

[Denys Vlasenko]

On Monday 09 August 2010 19:31, Missae Sasaya wrote:
> I am trying to use the ntpd applet in my application (Busybox 1.16),
> but I am having a hard time getting documentation on how to use it.
> 
> It seems the Busybox ntpd does not read from /etc/ntp.conf, right?
> Then I looked for the option "-g". It does not appear in the help
> message, but I tried anyway and it seems to work.
> 
> Can someone tell me where to find the available options?

They are documented in --help:

# busybox ntpd --help
BusyBox v1.18.0.git (2010-08-06 20:23:55 CEST) multi-call binary.

Usage: ntpd [-dnqwl] [-S PROG] [-p PEER]...

NTP client/server

Options:
        -d      Verbose
        -n      Do not daemonize
        -q      Quit after clock is set
        -w      Do not set time (only query peers), implies -n
        -l      Run as server on port 123
        -S PROG Run PROG after stepping time, stratum change, and every 11 mins
        -p PEER Obtain time from PEER (may be repeated)


As you noticed, these are not all. -g is also accepted.
Look at ntpd.c:

        opts = getopt32(argv,
                        "nqNx" /* compat */
                        "wp:S:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
                        "d" /* compat */
                        "46aAbgL", /* compat, ignored */

-g and a few more are accepted but has no effect. That's why they are
not documented: to not fool the user that they do anything.

-N "nice myself"
   is not documented because user can simply use nice to the same effect
   (but -N does work)

-x "disable stepping"
   is not documented because it currently isn't working -
   ntpd will step even with -x

-- 
vda