From 37aa66484c106adbc966a33865ca637ecf8af9a3 Mon Sep 17 00:00:00 2001
From: Lei Jitang <leijitang@huawei.com>
Date: Wed, 24 May 2017 13:02:09 -0400
Subject: [PATCH] Add SIGUSR1 to print the stack of containerd

Signed-off-by: Lei Jitang <leijitang@huawei.com>
---
 cmd/containerd/main.go       | 16 ++++++++++++++++
 cmd/containerd/main_linux.go |  2 ++
 cmd/containerd/main_unix.go  |  2 ++
 3 files changed, 20 insertions(+)

diff --git a/cmd/containerd/main.go b/cmd/containerd/main.go
index 0c3907763..3a6e8a14b 100644
--- a/cmd/containerd/main.go
+++ b/cmd/containerd/main.go
@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	"runtime"
 	"time"
 
 	"github.com/boltdb/bolt"
@@ -436,3 +437,18 @@ func interceptor(ctx gocontext.Context,
 	}
 	return grpc_prometheus.UnaryServerInterceptor(ctx, req, info, handler)
 }
+
+func dumpStacks() {
+	var (
+		buf       []byte
+		stackSize int
+	)
+	bufferLen := 16384
+	for stackSize == len(buf) {
+		buf = make([]byte, bufferLen)
+		stackSize = runtime.Stack(buf, true)
+		bufferLen *= 2
+	}
+	buf = buf[:stackSize]
+	logrus.Infof("=== BEGIN goroutine stack dump ===\n%s\n=== END goroutine stack dump ===", buf)
+}
diff --git a/cmd/containerd/main_linux.go b/cmd/containerd/main_linux.go
index 0717e785b..91558dbe8 100644
--- a/cmd/containerd/main_linux.go
+++ b/cmd/containerd/main_linux.go
@@ -50,6 +50,8 @@ func handleSignals(signals chan os.Signal, server *grpc.Server) error {
 			if err := reaper.Reap(); err != nil {
 				log.G(global).WithError(err).Error("reap containerd processes")
 			}
+		case unix.SIGUSR1:
+			dumpStacks()
 		default:
 			server.Stop()
 			return nil
diff --git a/cmd/containerd/main_unix.go b/cmd/containerd/main_unix.go
index 24ccab7e2..3059244e9 100644
--- a/cmd/containerd/main_unix.go
+++ b/cmd/containerd/main_unix.go
@@ -39,6 +39,8 @@ func handleSignals(signals chan os.Signal, server *grpc.Server) error {
 			if err := reaper.Reap(); err != nil {
 				log.G(global).WithError(err).Error("reap containerd processes")
 			}
+		case unix.SIGUSR1:
+			dumpStacks()
 		default:
 			server.Stop()
 			return nil