From 89b4f6e9f6e604b3b17a2eb398271ad56a23fc86 Mon Sep 17 00:00:00 2001
From: Yousong Zhou <zhouyousong@yunionyun.com>
Date: Thu, 15 Apr 2021 19:16:43 +0800
Subject: [PATCH] ansibleserver: wait zombie subprocesses

---
 pkg/ansibleserver/service/service.go |   3 +
 pkg/ansibleserver/service/zombie.go  | 118 +++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 pkg/ansibleserver/service/zombie.go

diff --git a/pkg/ansibleserver/service/service.go b/pkg/ansibleserver/service/service.go
index 4c891dcafe..67c89c615f 100644
--- a/pkg/ansibleserver/service/service.go
+++ b/pkg/ansibleserver/service/service.go
@@ -15,6 +15,7 @@
 package service
 
 import (
+	"context"
 	"os"
 
 	_ "github.com/go-sql-driver/mysql"
@@ -48,5 +49,7 @@ func StartService() {
 	db.EnsureAppInitSyncDB(app, dbOpts, models.InitDB)
 	defer cloudcommon.CloseDB()
 
+	go ReapZomebieLoop(context.TODO())
+
 	common_app.ServeForever(app, baseOpts)
 }
diff --git a/pkg/ansibleserver/service/zombie.go b/pkg/ansibleserver/service/zombie.go
new file mode 100644
index 0000000000..224e054df6
--- /dev/null
+++ b/pkg/ansibleserver/service/zombie.go
@@ -0,0 +1,118 @@
+// Copyright 2019 Yunion
+//
+// 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 service
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"yunion.io/x/log"
+)
+
+func ReapZomebieLoop(ctx context.Context) {
+	myPid := os.Getpid()
+	if myPid != 1 {
+		log.Infof("My pid is not 1 and no need to wait zombies")
+		return
+	}
+	myPidStr := fmt.Sprintf("%d", myPid)
+
+	tick := time.NewTicker(31 * time.Second)
+	for {
+		dirs, err := ioutil.ReadDir("/proc")
+		if err != nil {
+			log.Errorf("read /proc dir: %v", err)
+		}
+		for _, dir := range dirs {
+			// /proc/<pid>/
+			if !dir.IsDir() {
+				continue
+			}
+			name := dir.Name()
+			allDigits := true
+			for _, c := range name {
+				if c < '0' || c > '9' {
+					allDigits = false
+					break
+				}
+			}
+			if !allDigits {
+				continue
+			}
+
+			// read /proc/<pid>/stat
+			statPath := filepath.Join("/proc", name, "stat")
+			data, err := ioutil.ReadFile(statPath)
+			if err != nil {
+				log.Errorf("read %s: %v", statPath, err)
+				continue
+			}
+			dataStr := string(data)
+			items := strings.Split(dataStr, " ")
+			const (
+				idxPid    = iota
+				idxName   = iota
+				idxState  = iota
+				idxPpid   = iota
+				idxMinLen = iota
+			)
+			if len(items) < idxMinLen {
+				log.Errorf("%s contains less than %d items: %s", statPath, idxMinLen, dataStr)
+			}
+
+			// my zombie subprocesses
+			state := items[idxState]
+			if state != "Z" {
+				continue
+			}
+			ppidStr := items[idxPpid]
+			if ppidStr != myPidStr {
+				continue
+			}
+
+			// wait it
+			pname := items[idxName]
+			pidStr := items[idxPid]
+			pid, err := strconv.Atoi(pidStr)
+			if err != nil {
+				log.Errorf("%s: %s has invalid pid number %q: %v", pname, statPath, pidStr, err)
+				continue
+			}
+			var (
+				status syscall.WaitStatus
+				rusage syscall.Rusage
+			)
+			pid1, err := syscall.Wait4(pid, &status, 0, &rusage)
+			if err != nil {
+				log.Errorf("%s: %s: wait error: %v", pname, statPath, err)
+				continue
+			}
+			if pid1 == pid {
+				log.Infof("%s: pid %d: wait done", pname, pid)
+			}
+		}
+		select {
+		case <-ctx.Done():
+		case <-tick.C:
+		}
+	}
+}