setupIO: close conn on error

While it does not make much sense practically, as runc is going to exit
soon and all fds will be closed anyway, various linters (including
SVACE) keep reporting this.

Let's make them happy.

Reported-by: Tigran Sogomonian <[email protected]>
Reported-by: Mikhail Dmitrichenko <[email protected]>
Signed-off-by: Kir Kolyshkin <[email protected]>

Author: kolyshkin

utils_linux.go

@@ -95,7 +95,7 @@ func newProcess(p *specs.Process) (*libcontainer.Process, error) {
 }
 
 // setupIO modifies the given process config according to the options.
-func setupIO(process *libcontainer.Process, container *libcontainer.Container, createTTY, detach bool, sockpath string) (*tty, error) {
+func setupIO(process *libcontainer.Process, container *libcontainer.Container, createTTY, detach bool, sockpath string) (_ *tty, Err error) {
 	if createTTY {
 		process.Stdin = nil
 		process.Stdout = nil
@@ -121,6 +121,11 @@ func setupIO(process *libcontainer.Process, container *libcontainer.Container, c
 			if err != nil {
 				return nil, err
 			}
+			defer func() {
+				if Err != nil {
+					conn.Close()
+				}
+			}()
 			t.postStart = append(t.postStart, conn)
 			socket, err := conn.(*net.UnixConn).File()
 			if err != nil {