Track process uptime

kernel/time/time.c

@@ -94,3 +94,45 @@ timeunix_t time_tounix(Time *time) {
   secs += time->second;
   return secs;
 }
+
+void timeunix_totime(timeunix_t unix, Time *time) {
+  uint64_t days = unix / 86400;
+  uint32_t rem = days % 86400;
+
+  time->hour = rem / 3600;
+  time->minute = (rem % 3600) / 60;
+  time->second = rem % 60;
+
+  uint32_t year = 1970;
+  for (;;) {
+    uint32_t ydays = time_isleap(year) ? 366 : 365;
+    if (days >= ydays) {
+      days -= ydays;
+      year++;
+    } else {
+      break;
+    }
+  }
+  time->year = year;
+
+  bool leap = time_isleap(year);
+  uint32_t month = 0;
+  while (month < 11) {
+    uint32_t next = days_before_month[month + 1];
+    if (leap && month + 1 > 1) {
+      next++;
+    }
+    if (days < next) {
+      break;
+    }
+    month++;
+  }
+
+  uint32_t month_start = days_before_month[month];
+  if (leap && month > 1) {
+    month_start++;
+  }
+
+  time->month = month + 1;
+  time->day = (days - month_start) + 1;
+}