Try to debug test_recvif on OSX. Don't merge!

Author: asomers

src/sys/socket/mod.rs

@@ -885,7 +885,10 @@ pub fn recvmsg<'a>(fd: RawFd, iov: &[IoVec<&mut [u8]>],
                 // got control message(s)
                 debug_assert!(!mhdr.msg_control.is_null());
                 debug_assert!(msg_controllen >= mhdr.msg_controllen as usize);
-                CMSG_FIRSTHDR(&mhdr as *const msghdr)
+                let hdr = CMSG_FIRSTHDR(&mhdr as *const msghdr);
+                println!("cmsghdr: cmsg_len={}, cmsg_level={}, cmsg_type={}",
+                         (*hdr).cmsg_len, (*hdr).cmsg_level, (*hdr).cmsg_type);
+                hdr
             } else {
                 ptr::null()
             }.as_ref()

test/sys/test_socket.rs

@@ -708,6 +708,9 @@ pub fn test_recvif() {
                         panic!("unexpected Sockaddr");
                     }
                 },
+                ControlMessageOwned::Unknown(_) => {
+                    panic!("Unexpected unknown control message");
+                }
                 _ => panic!("unexpected additional control msg"),
             }
         }