1 files changed, 41 insertions, 0 deletions
diff --git a/pkg/sentry/kernel/tty.go b/pkg/sentry/kernel/tty.go
new file mode 100644
index 000000000..d0e0810e8
--- /dev/null
+++ b/pkg/sentry/kernel/tty.go
@@ -0,0 +1,41 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package kernel
+
+import "gvisor.dev/gvisor/pkg/sync"
+
+// TTY defines the relationship between a thread group and its controlling
+// terminal.
+//
+// +stateify savable
+type TTY struct {
+	// Index is the terminal index. It is immutable.
+	Index uint32
+
+	mu sync.Mutex `state:"nosave"`
+
+	// tg is protected by mu.
+	tg *ThreadGroup
+}
+
+// TTY returns the thread group's controlling terminal. If nil, there is no
+// controlling terminal.
+func (tg *ThreadGroup) TTY() *TTY {
+	tg.pidns.owner.mu.RLock()
+	defer tg.pidns.owner.mu.RUnlock()
+	tg.signalHandlers.mu.Lock()
+	defer tg.signalHandlers.mu.Unlock()
+	return tg.tty
+}