[LTP] [PATCH 2/3] lib: implement rtctime_save and rtctime_restore function

Cyril Hrubis
2021-01-07T13:57:44Z

> static struct timespec real_begin, mono_begin;
>
> +static struct rtc_time rtc_begin;
> +
> static int clock_saved;
>
> void tst_wallclock_save(void)
> @@ -58,3 +61,42 @@ void tst_wallclock_restore(void)
> if (tst_clock_settime(CLOCK_REALTIME, &adjust))
> tst_brk(TBROK | TERRNO, "tst_clock_settime() realtime failed");
> }
> +
> +void tst_rtctime_save(void)
> +{
> + /* save initial monotonic time to restore it when needed */
> + if (tst_rtc_gettime(&rtc_begin))
> + tst_brk(TBROK | TERRNO, "tst_rtc_gettime() realtime failed");
> +
> + if (tst_clock_gettime(CLOCK_MONOTONIC_RAW, &mono_begin))
> + tst_brk(TBROK | TERRNO, "tst_clock_gettime() monotonic failed");
> +
> + clock_saved = 1;

It would be better if we defined rtc_clock_saved for the rtc* functions
instead.

> +}
> +
> +void tst_rtctime_restore(void)
> +{
> + static struct timespec mono_end, elapsed;
> + static struct timespec rtc_begin_tm, rtc_adjust;
> + static struct rtc_time rtc_restore;
> +
> + if (!clock_saved)
> + return;
> +
> + clock_saved = 0;
> +
> + if (tst_clock_gettime(CLOCK_MONOTONIC_RAW, &mono_end))
> + tst_brk(TBROK | TERRNO, "tst_clock_gettime() monotonic failed");
> +
> + elapsed = tst_timespec_diff(mono_end, mono_begin);
> +
> + rtc_begin_tm.tv_sec = tst_rtc_tm_to_time(&rtc_begin);

We should clear the tv_nsec here otherwise it will contain garbage.

> + rtc_adjust = tst_timespec_add(rtc_begin_tm, elapsed);
> +
> + tst_rtc_time_to_tm(rtc_adjust.tv_sec, &rtc_restore);
> +
> + /* restore realtime clock based on monotonic delta */
> + if (tst_rtc_settime(&rtc_restore))
> + tst_brk(TBROK | TERRNO, "tst_rtc_settime() realtime failed");
> +}

Other than this, it looks good.

--
Cyril Hrubis
chrubis@suse.cz