-    *++s1 = '\0';
-  while (--n > 0);
-
-  return s;
+  size_t size = __strnlen (s2, n);
+  if (size != n)
+    memset (s1 + size, '\0', n - size);
+  return memcpy (s1, s2, size);
 }
 libc_hidden_builtin_def (strncpy)
diff --git a/sysdeps/gnu/bits/utmp.h b/sysdeps/gnu/bits/utmp.h
index aed2750..434a533 100644
--- a/sysdeps/gnu/bits/utmp.h
+++ b/sysdeps/gnu/bits/utmp.h
@@ -59,10 +59,14 @@ struct utmp
 {