timeutils: match today day and this year correctly

Assumption all years since 1970 have been exactly 365 days long has it's
problems when leap years happen.  Lets use struct tm fields that are
provided by localtime_r(), making year and day to be correctly compared even
when it's late new years eve somewhere else than UTC-0.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

1 files changed, 15 insertions, 12 deletions

diff --git a/lib/timeutils.c b/lib/timeutils.c
index 9c286aebc..d403ced90 100644
--- a/lib/timeutils.c
+++ b/lib/timeutils.c
@@ -503,34 +503,37 @@ int strtime_iso(const time_t *t, int flags, char *buf, size_t bufsz)
 }
 
 /* relative time functions */
-int time_is_today(const time_t *t, struct timeval *now)
+static inline int time_is_thisyear(struct tm const *const tm,
+				   struct tm const *const tmnow)
 {
-	if (now->tv_sec == 0)
-		gettimeofday(now, NULL);
-	return *t / (3600 * 24) == now->tv_sec / (3600 * 24);
+	return tm->tm_year == tmnow->tm_year;
 }
 
-int time_is_thisyear(const time_t *t, struct timeval *now)
+static inline int time_is_today(struct tm const *const tm,
+				struct tm const *const tmnow)
 {
-	if (now->tv_sec == 0)
-		gettimeofday(now, NULL);
-	return *t / (3600 * 24 * 365) == now->tv_sec / (3600 * 24 * 365);
+	return (tm->tm_yday == tmnow->tm_yday &&
+		time_is_thisyear(tm, tmnow));
 }
 
 int strtime_short(const time_t *t, struct timeval *now, int flags, char *buf, size_t bufsz)
 {
-        struct tm tm;
+	struct tm tm, tmnow;
 	int rc = 0;
 
-        localtime_r(t, &tm);
+	if (now->tv_sec == 0)
+		gettimeofday(now, NULL);
+
+	localtime_r(t, &tm);
+	localtime_r(&now->tv_sec, &tmnow);
 
-	if (time_is_today(t, now)) {
+	if (time_is_today(&tm, &tmnow)) {
 		rc = snprintf(buf, bufsz, "%02d:%02d", tm.tm_hour, tm.tm_min);
 		if (rc < 0 || (size_t) rc > bufsz)
 			return -1;
 		rc = 1;
 
-	} else if (time_is_thisyear(t, now)) {
+	} else if (time_is_thisyear(&tm, &tmnow)) {
 		if (flags & UL_SHORTTIME_THISYEAR_HHMM)
 			rc = strftime(buf, bufsz, "%b%d/%H:%M", &tm);
 		else