container: normalize closed CRI pipe read errors

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/headers/cri/pipe.go

@@ -159,6 +159,15 @@ func (c *pipeConn) Read(p []byte) (int, error) {
 		}
 	})
 	if err != nil {
+		// Control can reject a closed file before invoking the callback.
+		c.mu.Lock()
+		closed := c.closed
+		c.mu.Unlock()
+
+		if closed {
+			err = os.ErrClosed
+		}
+
 		return 0, err
 	}
 

internal/headers/cri/pipe_internal_test.go

@@ -280,6 +280,11 @@ func TestPipeConnClose(t *testing.T) {
 	case <-time.After(5 * time.Second):
 		t.Fatal("Close did not release the pipe handle")
 	}
+
+	// A read started after Close must return the same error as a canceled read.
+	n, err := server.Read(make([]byte, 1))
+	require.Zero(t, n)
+	require.ErrorIs(t, err, os.ErrClosed)
 }
 
 // Both peers write first. On a pipe without buffer, this blocks both writes