[systemd-devel] [PATCH] timedated: Add a LocalOffset property for timezone offset

[David Herrmann]

Hi

On Thu, Mar 19, 2015 at 11:24 AM, Stef Walter <stefw at redhat.com> wrote:
> This property is in usec (like the TimeUSec property) and allows
> retrieving the timezone offset for the machine. This is particularly
> usable for remote callers.
> ---
>  src/timedate/timedated.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
> index ca771d5..e384b36 100644
> --- a/src/timedate/timedated.c
> +++ b/src/timedate/timedated.c
> @@ -361,6 +361,22 @@ static int property_get_time(
>          return sd_bus_message_append(reply, "t", now(CLOCK_REALTIME));
>  }
>
> +static int property_get_local_offset(
> +                sd_bus *bus,
> +                const char *path,
> +                const char *interface,
> +                const char *property,
> +                sd_bus_message *reply,
> +                void *userdata,
> +                sd_bus_error *error)
> +{
> +        struct tm *tm;
> +        time_t dummy = 0;
> +
> +        assert_se(tm = localtime(&dummy));
> +        return sd_bus_message_append(reply, "t", (uint64_t)(tm->tm_gmtoff * 1000000));
> +}
> +

Hmm, so this is a convenience call. You could just set tm.tm_zone
locally and use mktime() with the value retrieved by "Timezone"? Yeah,
the time-api is awful with global variables, but that's not really our
fault, is it?

I'm not really against this bus-call, but I also don't see the point.
There's much more information in a timezone file than the offset, so
why expose the offset but not the other data?

Thanks
David

>  static int property_get_ntp_sync(
>                  sd_bus *bus,
>                  const char *path,
> @@ -440,7 +456,8 @@ static int method_set_timezone(sd_bus *bus, sd_bus_message *m, void *userdata, s
>                     LOG_MESSAGE("Changed time zone to '%s'.", c->zone),
>                     NULL);
>
> -        sd_bus_emit_properties_changed(bus, "/org/freedesktop/timedate1", "org.freedesktop.timedate1", "Timezone", NULL);
> +        sd_bus_emit_properties_changed(bus, "/org/freedesktop/timedate1", "org.freedesktop.timedate1",
> +                                       "Timezone", "LocalOffset", NULL);
>
>          return sd_bus_reply_method_return(m, NULL);
>  }
> @@ -666,6 +683,7 @@ static int method_set_ntp(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bus
>  static const sd_bus_vtable timedate_vtable[] = {
>          SD_BUS_VTABLE_START(0),
>          SD_BUS_PROPERTY("Timezone", "s", NULL, offsetof(Context, zone), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
> +        SD_BUS_PROPERTY("LocalOffset", "t", property_get_local_offset, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
>          SD_BUS_PROPERTY("LocalRTC", "b", bus_property_get_bool, offsetof(Context, local_rtc), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
>          SD_BUS_PROPERTY("CanNTP", "b", bus_property_get_bool, offsetof(Context, can_ntp), 0),
>          SD_BUS_PROPERTY("NTP", "b", bus_property_get_bool, offsetof(Context, use_ntp), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
> --
> 2.3.3
>
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