Merge pull request #23865 from rhcarvalho/unify-signal-handling

Automatic merge from submit-queue

Unify termination signal handling across platforms

The signals are used to ensure proper execution of cleaning up actions to restore a terminal in:
- [pkg/kubectl/cmd/attach.go#L163-L226](b8d000853e/pkg/kubectl/cmd/attach.go (L163-L226))
- [pkg/kubectl/cmd/util/editor/editor.go#L112-L137](b8d000853e/pkg/kubectl/cmd/util/editor/editor.go (L112-L137))

All supported platforms can handle the same set of signals we're interested in, thus we don't need build contraints to use a set of signals on Linux, while restricting ourselves to only SIGINT on Darwin and Windows.

According to the documentation of os/signal, similar to SIGINT and SIGTERM, SIGHUP causes the program to exit, therefore add it to the list of handled signals.

The fist commit is part of #23643.

pkg/util/interrupt/child.go

@@ -1,26 +0,0 @@
-// +build !linux
-
-/*
-Copyright 2016 The Kubernetes Authors All rights reserved.
-
-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 interrupt
-
-import (
-	"os"
-)
-
-// childSignals are the allowed signals that can be sent to children in Windows to terminate
-var childSignals = []os.Signal{os.Interrupt}

pkg/util/interrupt/child_linux.go

@@ -1,27 +0,0 @@
-// +build linux
-
-/*
-Copyright 2016 The Kubernetes Authors All rights reserved.
-
-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 interrupt
-
-import (
-	"os"
-	"syscall"
-)
-
-// childSignals are the allowed signals that can be sent to children in Unix variant OS's
-var childSignals = []os.Signal{syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT}

pkg/util/interrupt/interrupt.go

@@ -20,8 +20,13 @@ import (
 	"os"
 	"os/signal"
 	"sync"
+	"syscall"
 )
 
+// terminationSignals are signals that cause the program to exit in the
+// supported platforms (linux, darwin, windows).
+var terminationSignals = []os.Signal{syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT}
+
 // Handler guarantees execution of notifications after a critical section (the function passed
 // to a Run method), even in the presence of process termination. It guarantees exactly once
 // invocation of the provided notify functions.
@@ -82,7 +87,7 @@ func (h *Handler) Signal(s os.Signal) {
 // per Handler instance, so calling Run more than once will not behave as the user expects.
 func (h *Handler) Run(fn func() error) error {
 	ch := make(chan os.Signal, 1)
-	signal.Notify(ch, childSignals...)
+	signal.Notify(ch, terminationSignals...)
 	defer func() {
 		signal.Stop(ch)
 		close(ch)