We use mktime(3) for portability. http://www.gnu.org/software/libc/manual/html_mono/libc.html#index-timegm Portability note: mktime is essentially universally available. timegm is rather rare. For the most portable conversion from a UTC broken-down time to a simple time, set the TZ environment variable to UTC, call mktime, then set TZ back. On 07/10/2016 04:02 PM, Sami Kerola wrote: > There is no need to re-implement timegm() by removing TZ localization for a > moment, just use timegm(3) instead. > > Signed-off-by: Sami Kerola <kerolasa@xxxxxx> > --- > sys-utils/hwclock.c | 34 +++++----------------------------- > 1 file changed, 5 insertions(+), 29 deletions(-) > > diff --git a/sys-utils/hwclock.c b/sys-utils/hwclock.c > index e98c2c0..bcaab8b 100644 > --- a/sys-utils/hwclock.c > +++ b/sys-utils/hwclock.c > @@ -388,27 +388,11 @@ static void > mktime_tz(struct tm tm, const bool universal, > bool * valid_p, time_t * systime_p) > { > - time_t mktime_result; /* The value returned by our mktime() call */ > - char *zone; /* Local time zone name */ > - > - /* > - * We use the C library function mktime(), but since it only works > - * on local time zone input, we may have to fake it out by > - * temporarily changing the local time zone to UTC. > - */ > - zone = getenv("TZ"); /* remember original time zone */ > - if (universal) { > - /* Set timezone to UTC */ > - setenv("TZ", "", TRUE); > - /* > - * Note: tzset() gets called implicitly by the time code, > - * but only the first time. When changing the environment > - * variable, better call tzset() explicitly. > - */ > - tzset(); > - } > - mktime_result = mktime(&tm); > - if (mktime_result == -1) { > + if (universal) > + *systime_p = timegm(&tm); > + else > + *systime_p = mktime(&tm); > + if (*systime_p == -1) { > /* > * This apparently (not specified in mktime() documentation) > * means the 'tm' structure does not contain valid values > @@ -416,7 +400,6 @@ mktime_tz(struct tm tm, const bool universal, > * mktime() returns -1). > */ > *valid_p = FALSE; > - *systime_p = 0; > if (debug) > printf(_("Invalid values in hardware clock: " > "%4d/%.2d/%.2d %.2d:%.2d:%.2d\n"), > @@ -424,7 +407,6 @@ mktime_tz(struct tm tm, const bool universal, > tm.tm_hour, tm.tm_min, tm.tm_sec); > } else { > *valid_p = TRUE; > - *systime_p = mktime_result; > if (debug) > printf(_ > ("Hw clock time : %4d/%.2d/%.2d %.2d:%.2d:%.2d = " > @@ -432,12 +414,6 @@ mktime_tz(struct tm tm, const bool universal, > tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, > tm.tm_sec, (long)*systime_p); > } > - /* now put back the original zone. */ > - if (zone) > - setenv("TZ", zone, TRUE); > - else > - unsetenv("TZ"); > - tzset(); > } > > /* > -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
