1 files changed, 14 insertions, 1 deletions
diff --git a/src/basic/time-util.h b/src/basic/time-util.h
index 7321e3c670..9c7758a959 100644
--- a/src/basic/time-util.h
+++ b/src/basic/time-util.h
@@ -69,7 +69,7 @@ typedef struct dual_timestamp {
 #define FORMAT_TIMESTAMP_RELATIVE_MAX 256
 #define FORMAT_TIMESPAN_MAX 64
 
-#define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+#define TIME_T_MAX (time_t)((UINTMAX_C(1) << ((sizeof(time_t) << 3) - 1)) - 1)
 
 #define DUAL_TIMESTAMP_NULL ((struct dual_timestamp) { 0ULL, 0ULL })
 
@@ -127,3 +127,16 @@ time_t mktime_or_timegm(struct tm *tm, bool utc);
 struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc);
 
 unsigned long usec_to_jiffies(usec_t usec);
+
+static inline usec_t usec_add(usec_t a, usec_t b) {
+        usec_t c;
+
+        /* Adds two time values, and makes sure USEC_INFINITY as input results as USEC_INFINITY in output, and doesn't
+         * overflow. */
+
+        c = a + b;
+        if (c < a || c < b) /* overflow check */
+                return USEC_INFINITY;
+
+        return c;
+}