Fix TestIfSocketCloses

nl/nl_linux_test.go

@@ -7,6 +7,7 @@ import (
 	"reflect"
 	"testing"
 	"time"
+	_ "unsafe"
 
 	"golang.org/x/sys/unix"
 )
@@ -63,22 +64,22 @@ func TestIfInfomsgDeserializeSerialize(t *testing.T) {
 	testDeserializeSerialize(t, orig, safemsg, msg)
 }
 
+//go:linkname errFileClosing internal/poll.ErrFileClosing
+var errFileClosing error
+
 func TestIfSocketCloses(t *testing.T) {
 	nlSock, err := Subscribe(unix.NETLINK_ROUTE, unix.RTNLGRP_NEIGH)
 	if err != nil {
 		t.Fatalf("Error on creating the socket: %v", err)
 	}
-	nlSock.SetReceiveTimeout(&unix.Timeval{Sec: 2, Usec: 0})
 	endCh := make(chan error)
 	go func(sk *NetlinkSocket, endCh chan error) {
 		endCh <- nil
-		for {
-			_, _, err := sk.Receive()
-			// Receive returned because of a timeout and the FD == -1 means that the socket got closed
-			if err == unix.EAGAIN && nlSock.GetFd() == -1 {
-				endCh <- err
-				return
-			}
+		_, _, err := sk.Receive()
+		if err == errFileClosing {
+			endCh <- err
+		} else {
+			endCh <- nil
 		}
 	}(nlSock, endCh)