log: handle integer overflow in timestamps

diff --git a/date.c b/date.c
index 57331ed406e2391e0a2bf327fbb86d3b62012324..2dae471dd124006a66b7fcdab97e61fdc792a30e 100644 (file)
--- a/date.c
+++ b/date.c
@@ -1085,3 +1085,20 @@ unsigned long approxidate_careful(const char *date, int *error_ret)
        gettimeofday(&tv, NULL);
        return approxidate_str(date, &tv, error_ret);
 }
+
+int date_overflows(unsigned long t)
+{
+       time_t sys;
+
+       /* If we overflowed our unsigned long, that's bad... */
+       if (t == ULONG_MAX)
+               return 1;
+
+       /*
+        * ...but we also are going to feed the result to system
+        * functions that expect time_t, which is often "signed long".
+        * Make sure that we fit into time_t, as well.
+        */
+       sys = t;
+       return t != sys || (t < 1) != (sys < 1);
+}