diff --git a/gcc/ada/g-os_lib.adb b/gcc/ada/g-os_lib.adb
index dbfc6b9174538db099fc407bd53eaa5bc1e10883..c1efa039092960f58324c670f03f9336ee48a8e6 100644
--- a/gcc/ada/g-os_lib.adb
+++ b/gcc/ada/g-os_lib.adb
@@ -384,7 +384,14 @@ package body GNAT.OS_Lib is
          procedure Free is new Unchecked_Deallocation (Buf, Buf_Ptr);
 
       begin
+         --  Check for invalid descriptors, making sure that we do not
+         --  accidentally leave an open file descriptor around.
+
          if From = Invalid_FD then
+            if To /= Invalid_FD then
+               Close (To, Status_To);
+            end if;
+
             raise Copy_Error;
 
          elsif To = Invalid_FD then