diff --git a/src/util.c b/src/util.c
new file mode 100644
index 0000000..afea3cb
--- /dev/null
+++ b/src/util.c
@@ -0,0 +1,11 @@
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "util.h"
+
+void* _util_safe_container_of_helper(void* ptr, size_t offset) {
+  if (ptr == NULL)
+    return NULL;
+  else
+    return (char*) ptr - offset;
+}
diff --git a/src/util.h b/src/util.h
index 6d1f6bf..2761d71 100644
--- a/src/util.h
+++ b/src/util.h
@@ -3,6 +3,8 @@
 
 #include <stddef.h>
 
+#include "internal.h"
+
 #ifndef _SSIZE_T_DEFINED
 #define SSIZE_T_DEFINED
 typedef intptr_t ssize_t;
@@ -10,6 +12,9 @@ typedef intptr_t ssize_t;
 
 #define array_count(a) (sizeof(a) / (sizeof((a)[0])))
 
+#define safe_container_of(ptr, type, member) \
+  ((type*) _util_safe_container_of_helper((ptr), offsetof(type, member)))
+
 #define container_of(ptr, type, member) \
   ((type*) ((char*) (ptr) -offsetof(type, member)))
 
@@ -21,4 +26,6 @@ typedef intptr_t ssize_t;
     (unused)) int __static_assert_##__LINE__[(condition) ? 1 : -1];
 #endif
 
+EPOLL_INTERNAL void* _util_safe_container_of_helper(void* ptr, size_t offset);
+
 #endif /* EPOLL_UTIL_H_ */