modbuslog: use time.h functions to manipulate datev1.5

Fixes issue that became apparent after switch to DST

1 files changed, 9 insertions, 4 deletions

diff --git a/src/modbuslog.c b/src/modbuslog.c
index 43d102d..d967e4a 100644
--- a/src/modbuslog.c
+++ b/src/modbuslog.c
@@ -156,7 +156,9 @@ int main(int argc, char *argv[]) {
 		select(0, NULL, NULL, NULL, NULL);
 
 		time_t t = time(NULL);
-		time_t unixtime_min = (((int) t) / 60 * 60);
+		struct tm unixtime_min_time_t = *gmtime (&t);
+		unixtime_min_time_t.tm_sec = 0;
+		time_t unixtime_min = mktime(&unixtime_min_time_t);
 		//int unixtime = (int) t;
 		//printf("%d\n", unixtime);
 
@@ -281,9 +283,12 @@ int main(int argc, char *argv[]) {
 				//MODBUS_SET_INT16_TO_INT8(tab_int8, index, value);
 
 				// round forward to next midnight
-				time_t unixtime_day = ((((int) t) / 86400 * 86400) + 86400);
-
-				struct tm midnight = *localtime(&unixtime_day);
+				struct tm midnight = *localtime(&t);
+				midnight.tm_hour = 0;
+				midnight.tm_min = 0;
+				midnight.tm_sec = 0;
+				midnight.tm_mday += 1;
+				mktime (&midnight);
 
 				char log_filename[50];