[systemd-devel] [PATCH] timedated: when performing "SetTime" compensate for program lag

[Lennart Poettering]

On Fri, 13.02.15 15:34, Shawn Landden (shawn at churchofgit.com) wrote:

> ---
>  TODO                     |  2 --
>  src/timedate/timedated.c | 14 ++++++++++++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/TODO b/TODO
> index 68b0af6..7b93404 100644
> --- a/TODO
> +++ b/TODO
> @@ -190,8 +190,6 @@ Features:
>  * we should try harder to collapse start jobs for swaps that end up being the same:
>    http://lists.freedesktop.org/archives/systemd-devel/2014-November/025359.html
>  
> -* timedated should compensate on SetTime for the time spent in polkit
> -
>  * figure out when we can use the coarse timers
>  
>  * sd-resolve: drop res_query wrapping, people should call via the bus to resolved instead
> diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
> index 753c3d1..7948bfa 100644
> --- a/src/timedate/timedated.c
> +++ b/src/timedate/timedated.c
> @@ -529,6 +529,7 @@ static int method_set_time(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bu
>          Context *c = userdata;
>          int64_t utc;
>          struct timespec ts;
> +        usec_t start, ready;
>          struct tm* tm;
>          int r;
>  
> @@ -569,6 +570,19 @@ static int method_set_time(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bu
>          if (r == 0)
>                  return 1;
>  
> +        /* adjust ts for time spent in program */
> +        r = sd_bus_message_get_monotonic_usec(m, &start);
> +        if (r < 0) {
> +                /* we only get this data if we are using kdbus */
> +                if (r == -ENODATA)
> +                        goto nodata;
> +
> +                return r;
> +        }
> +        ready = now(CLOCK_MONOTONIC);
> +        timespec_store(&ts, timespec_load(&ts) + (ready - start));
> +nodata:
> +

It's ok to use "goto" for error cleanups, but in thise case this seems
unnecessary...

Also, to get timestamps you need to explicitly request them when
setting up the bus connection with sd_bus_negotiate_timestamp(),
otherwise messages will never carry timestamps.

Lennart

-- 
Lennart Poettering, Red Hat