Implement code review remarks

pkg/sentry/fsimpl/devpts/line_discipline.go

@@ -112,7 +112,7 @@ type lineDiscipline struct {
 	// replicaWaiter is used to wait on the replica end of the TTY.
 	replicaWaiter waiter.Queue
 
-	// terminal is the terminal linked to this lineDiscipline
+	// terminal is the terminal linked to this lineDiscipline.
 	terminal *Terminal
 }
 
@@ -123,10 +123,6 @@ func newLineDiscipline(termios linux.KernelTermios) *lineDiscipline {
 	return &ld
 }
 
-func (l *lineDiscipline) SetTerminal(tm *Terminal) {
-	l.terminal = tm
-}
-
 // getTermios gets the linux.Termios for the tty.
 func (l *lineDiscipline) getTermios(task *kernel.Task, args arch.SyscallArguments) (uintptr, error) {
 	l.termiosMu.RLock()

pkg/sentry/fsimpl/devpts/terminal.go

@@ -54,7 +54,8 @@ func newTerminal(n uint32) *Terminal {
 		replicaKTTY: &kernel.TTY{Index: n},
 	}
 
-	t.ld.SetTerminal(&t)
+	t.ld.terminal = &t
+
 	return &t
 }
 
@@ -111,9 +112,10 @@ func (tm *Terminal) setForegroundProcessGroup(ctx context.Context, args arch.Sys
 		return 0, err
 	}
 
-	tm.fgProcessGroup = task.ThreadGroup().ProcessGroup()
-
 	ret, err := task.ThreadGroup().SetForegroundProcessGroup(tm.tty(isMaster), kernel.ProcessGroupID(pgid))
+	if err == nil {
+		tm.fgProcessGroup = task.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(pgid))
+	}
 	return uintptr(ret), err
 }