From 7a1739a3e88ece75891aac216829df4979ecb841 Mon Sep 17 00:00:00 2001
From: Anthony Romano <anthony.romano@coreos.com>
Date: Tue, 9 May 2017 15:20:21 -0700
Subject: [PATCH] osutil: force SIG_DFL before resending terminating signal

The go runtime won't always reinstall the default signal handler on the
SIGTERM path, so it's possible the signal won't terminate the process.
Instead, force SIG_DFL for the signal.
---
 pkg/osutil/interrupt_unix.go |  1 +
 pkg/osutil/osutil.go         |  3 +++
 pkg/osutil/osutil_test.go    |  2 ++
 pkg/osutil/signal.go         | 19 +++++++++++++++++++
 pkg/osutil/signal_linux.go   | 30 ++++++++++++++++++++++++++++++
 5 files changed, 55 insertions(+)
 create mode 100644 pkg/osutil/signal.go
 create mode 100644 pkg/osutil/signal_linux.go

diff --git a/pkg/osutil/interrupt_unix.go b/pkg/osutil/interrupt_unix.go
index 2d1518a3b..b9feaffc9 100644
--- a/pkg/osutil/interrupt_unix.go
+++ b/pkg/osutil/interrupt_unix.go
@@ -68,6 +68,7 @@ func HandleInterrupts() {
 		if pid == 1 {
 			os.Exit(0)
 		}
+		setDflSignal(sig.(syscall.Signal))
 		syscall.Kill(pid, sig.(syscall.Signal))
 	}()
 }
diff --git a/pkg/osutil/osutil.go b/pkg/osutil/osutil.go
index 616e439ea..ef38280e7 100644
--- a/pkg/osutil/osutil.go
+++ b/pkg/osutil/osutil.go
@@ -24,6 +24,9 @@ import (
 
 var (
 	plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "pkg/osutil")
+
+	// support to override setting SIG_DFL so tests don't terminate early
+	setDflSignal = dflSignal
 )
 
 func Unsetenv(key string) error {
diff --git a/pkg/osutil/osutil_test.go b/pkg/osutil/osutil_test.go
index 8bc5ea8df..9fbc7a44c 100644
--- a/pkg/osutil/osutil_test.go
+++ b/pkg/osutil/osutil_test.go
@@ -23,6 +23,8 @@ import (
 	"time"
 )
 
+func init() { setDflSignal = func(syscall.Signal) {} }
+
 func TestUnsetenv(t *testing.T) {
 	tests := []string{
 		"data",
diff --git a/pkg/osutil/signal.go b/pkg/osutil/signal.go
new file mode 100644
index 000000000..17054acb7
--- /dev/null
+++ b/pkg/osutil/signal.go
@@ -0,0 +1,19 @@
+// Copyright 2017 The etcd 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.
+
+// +build !linux
+
+package osutil
+
+func dflSignal(sig syscall.Signal) { /* nop */ }
diff --git a/pkg/osutil/signal_linux.go b/pkg/osutil/signal_linux.go
new file mode 100644
index 000000000..305861710
--- /dev/null
+++ b/pkg/osutil/signal_linux.go
@@ -0,0 +1,30 @@
+// Copyright 2017 The etcd 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.
+
+// +build linux
+
+package osutil
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// dflSignal sets the given signal to SIG_DFL
+func dflSignal(sig syscall.Signal) {
+	// clearing out the sigact sets the signal to SIG_DFL
+	var sigactBuf [32]uint64
+	ptr := unsafe.Pointer(&sigactBuf)
+	syscall.Syscall6(uintptr(syscall.SYS_RT_SIGACTION), uintptr(sig), uintptr(ptr), 0, 8, 0, 0)
+}