From 3ae8e8a30b83a1887747475ec9f39b7487f3a6bb Mon Sep 17 00:00:00 2001
From: Michael Crosby <crosbymichael@gmail.com>
Date: Tue, 4 Dec 2018 11:43:52 -0500
Subject: [PATCH] Add shim config for shim binary options

Fixes #2855

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
---
 runtime/v2/shim/shim.go         | 31 +++++++++++++++++++++++++------
 runtime/v2/shim/shim_unix.go    | 17 +++++++++++++++--
 runtime/v2/shim/shim_windows.go |  2 +-
 3 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/runtime/v2/shim/shim.go b/runtime/v2/shim/shim.go
index 39484c191..d60d49663 100644
--- a/runtime/v2/shim/shim.go
+++ b/runtime/v2/shim/shim.go
@@ -62,6 +62,17 @@ type Opts struct {
 	Debug      bool
 }
 
+// BinaryOpts allows the configuration of a shims binary setup
+type BinaryOpts func(*Config)
+
+// Config of shim binary options provided by shim implementations
+type Config struct {
+	// NoSubreaper disables setting the shim as a child subreaper
+	NoSubreaper bool
+	// NoReaper disables the shim binary from reaping any child process implicitly
+	NoReaper bool
+}
+
 var (
 	debugFlag            bool
 	idFlag               string
@@ -118,27 +129,34 @@ func setLogger(ctx context.Context, id string) error {
 }
 
 // Run initializes and runs a shim server
-func Run(id string, initFunc Init) {
-	if err := run(id, initFunc); err != nil {
+func Run(id string, initFunc Init, opts ...BinaryOpts) {
+	var config Config
+	for _, o := range opts {
+		o(&config)
+	}
+	if err := run(id, initFunc, config); err != nil {
 		fmt.Fprintf(os.Stderr, "%s: %s\n", id, err)
 		os.Exit(1)
 	}
 }
 
-func run(id string, initFunc Init) error {
+func run(id string, initFunc Init, config Config) error {
 	parseFlags()
 	setRuntime()
 
-	signals, err := setupSignals()
+	signals, err := setupSignals(config)
 	if err != nil {
 		return err
 	}
-	if err := subreaper(); err != nil {
-		return err
+	if !config.NoSubreaper {
+		if err := subreaper(); err != nil {
+			return err
+		}
 	}
 	publisher := &remoteEventsPublisher{
 		address:              addressFlag,
 		containerdBinaryPath: containerdBinaryFlag,
+		noReaper:             config.NoReaper,
 	}
 	if namespaceFlag == "" {
 		return fmt.Errorf("shim namespace cannot be empty")
@@ -266,4 +284,5 @@ func dumpStacks(logger *logrus.Entry) {
 type remoteEventsPublisher struct {
 	address              string
 	containerdBinaryPath string
+	noReaper             bool
 }
diff --git a/runtime/v2/shim/shim_unix.go b/runtime/v2/shim/shim_unix.go
index 937aaaf0d..08668dc1c 100644
--- a/runtime/v2/shim/shim_unix.go
+++ b/runtime/v2/shim/shim_unix.go
@@ -39,9 +39,13 @@ import (
 
 // setupSignals creates a new signal handler for all signals and sets the shim as a
 // sub-reaper so that the container processes are reparented
-func setupSignals() (chan os.Signal, error) {
+func setupSignals(config Config) (chan os.Signal, error) {
 	signals := make(chan os.Signal, 32)
-	signal.Notify(signals, unix.SIGTERM, unix.SIGINT, unix.SIGCHLD, unix.SIGPIPE)
+	smp := []os.Signal{unix.SIGTERM, unix.SIGINT, unix.SIGPIPE}
+	if !config.NoReaper {
+		smp = append(smp, unix.SIGCHLD)
+	}
+	signal.Notify(signals, smp...)
 	return signals, nil
 }
 
@@ -102,6 +106,15 @@ func (l *remoteEventsPublisher) Publish(ctx context.Context, topic string, event
 	}
 	cmd := exec.CommandContext(ctx, l.containerdBinaryPath, "--address", l.address, "publish", "--topic", topic, "--namespace", ns)
 	cmd.Stdin = bytes.NewReader(data)
+	if l.noReaper {
+		if err := cmd.Start(); err != nil {
+			return err
+		}
+		if err := cmd.Wait(); err != nil {
+			return errors.Wrap(err, "failed to publish event")
+		}
+		return nil
+	}
 	c, err := Default.Start(cmd)
 	if err != nil {
 		return err
diff --git a/runtime/v2/shim/shim_windows.go b/runtime/v2/shim/shim_windows.go
index bd3f62aea..3bac959db 100644
--- a/runtime/v2/shim/shim_windows.go
+++ b/runtime/v2/shim/shim_windows.go
@@ -40,7 +40,7 @@ import (
 )
 
 // setupSignals creates a new signal handler for all signals
-func setupSignals() (chan os.Signal, error) {
+func setupSignals(config Config) (chan os.Signal, error) {
 	signals := make(chan os.Signal, 32)
 	return signals, nil
 }