Index: chrony-2.4/clknetsim-a5949fedf7e0f78a756bd29fe93fa1e4f72cdc42/client.c
===================================================================
--- chrony-2.4.orig/clknetsim-a5949fedf7e0f78a756bd29fe93fa1e4f72cdc42/client.c
+++ chrony-2.4/clknetsim-a5949fedf7e0f78a756bd29fe93fa1e4f72cdc42/client.c
@@ -954,6 +954,8 @@ int open(const char *pathname, int flags
 	else if (!strcmp(pathname, "/dev/ptp1"))
 		return SYSCLK_FD;
 
+	if (!_open)
+		_open = (int (*)(const char *pathname, int flags))dlsym(RTLD_NEXT, "open");
 	r = _open(pathname, flags);
 	assert(r < 0 || (r < BASE_SOCKET_FD && r < BASE_TIMER_FD));
 
@@ -972,6 +974,8 @@ int close(int fd) {
 		return 0;
 	}
 
+	if (!_close)
+		_close = (int (*)(int fd))dlsym(RTLD_NEXT, "close");
 	return _close(fd);
 }