From 76a8978c3e487d32b80b8cb55c07e69b10453a95 Mon Sep 17 00:00:00 2001
From: Marcin Matlaszek <mmatlaszek@gmail.com>
Date: Wed, 22 Nov 2017 00:51:39 +0100
Subject: [PATCH] Make starting & cleaning process group Windows compatible.

---
 client/driver/executor/executor.go       | 13 ++++++++++++-
 client/driver/executor/executor_linux.go |  9 ---------
 client/driver/executor/executor_unix.go  | 10 ++++++++++
 client/driver/raw_exec.go                |  4 ++--
 client/driver/utils.go                   | 10 ----------
 5 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/client/driver/executor/executor.go b/client/driver/executor/executor.go
index 41153730b..62a67c1bd 100644
--- a/client/driver/executor/executor.go
+++ b/client/driver/executor/executor.go
@@ -448,6 +448,17 @@ func ClientCleanup(ic *dstructs.IsolationConfig, pid int) error {
 	return clientCleanup(ic, pid)
 }
 
+// Cleanup any still hanging user processes
+func (e *UniversalExecutor) cleanupUserLeftovers(proc *os.Process) error {
+	// If new process group was created upon command execution
+	// we can kill the whole process group now to cleanup any leftovers.
+	if e.cmd.SysProcAttr != nil && e.cmd.SysProcAttr.Setpgid {
+		return syscall.Kill(-proc.Pid, syscall.SIGKILL)
+	} else {
+		return proc.Kill()
+	}
+}
+
 // Exit cleans up the alloc directory, destroys resource container and kills the
 // user process
 func (e *UniversalExecutor) Exit() error {
@@ -475,7 +486,7 @@ func (e *UniversalExecutor) Exit() error {
 		if err != nil {
 			e.logger.Printf("[ERR] executor: can't find process with pid: %v, err: %v",
 				e.cmd.Process.Pid, err)
-		} else if err := proc.Kill(); err != nil && err.Error() != finishedErr {
+		} else if err := e.cleanupUserLeftovers(proc); err != nil && err.Error() != finishedErr {
 			merr.Errors = append(merr.Errors,
 				fmt.Errorf("can't kill process with pid: %v, err: %v", e.cmd.Process.Pid, err))
 		}
diff --git a/client/driver/executor/executor_linux.go b/client/driver/executor/executor_linux.go
index fe9600eb9..ef1de7ebc 100644
--- a/client/driver/executor/executor_linux.go
+++ b/client/driver/executor/executor_linux.go
@@ -331,15 +331,6 @@ func DestroyCgroup(groups *cgroupConfig.Cgroup, cgPaths map[string]string, execu
 	return mErrs.ErrorOrNil()
 }
 
-// configure new process group for child process
-func (e *UniversalExecutor) setNewProcessGroup() error {
-	if e.cmd.SysProcAttr == nil {
-		e.cmd.SysProcAttr = &syscall.SysProcAttr{}
-	}
-	e.cmd.SysProcAttr.Setpgid = true
-	return nil
-}
-
 // getCgroupManager returns the correct libcontainer cgroup manager.
 func getCgroupManager(groups *cgroupConfig.Cgroup, paths map[string]string) cgroups.Manager {
 	return &cgroupFs.Manager{Cgroups: groups, Paths: paths}
diff --git a/client/driver/executor/executor_unix.go b/client/driver/executor/executor_unix.go
index 90efa32e6..cf2fc3f33 100644
--- a/client/driver/executor/executor_unix.go
+++ b/client/driver/executor/executor_unix.go
@@ -5,6 +5,7 @@ package executor
 import (
 	"fmt"
 	"io"
+	"syscall"
 
 	syslog "github.com/RackSec/srslog"
 
@@ -47,3 +48,12 @@ func (e *UniversalExecutor) collectLogs(we io.Writer, wo io.Writer) {
 		}
 	}
 }
+
+// configure new process group for child process
+func (e *UniversalExecutor) setNewProcessGroup() error {
+	if e.cmd.SysProcAttr == nil {
+		e.cmd.SysProcAttr = &syscall.SysProcAttr{}
+	}
+	e.cmd.SysProcAttr.Setpgid = true
+	return nil
+}
diff --git a/client/driver/raw_exec.go b/client/driver/raw_exec.go
index e8f6c5bd2..0cea2ea55 100644
--- a/client/driver/raw_exec.go
+++ b/client/driver/raw_exec.go
@@ -298,8 +298,8 @@ func (h *rawExecHandle) run() {
 	ps, werr := h.executor.Wait()
 	close(h.doneCh)
 	if ps.ExitCode == 0 && werr != nil {
-		if e := killProcessGroup(h.userPid); e != nil {
-			h.logger.Printf("[ERR] driver.raw_exec: error killing user process group: %v", e)
+		if e := killProcess(h.userPid); e != nil {
+			h.logger.Printf("[ERR] driver.raw_exec: error killing user process: %v", e)
 		}
 	}
 
diff --git a/client/driver/utils.go b/client/driver/utils.go
index c40387007..5fba8071f 100644
--- a/client/driver/utils.go
+++ b/client/driver/utils.go
@@ -8,7 +8,6 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
-	"syscall"
 	"time"
 
 	"github.com/hashicorp/consul-template/signals"
@@ -111,15 +110,6 @@ func killProcess(pid int) error {
 	return proc.Kill()
 }
 
-// killProcessGroup kills a process group with the given pid
-func killProcessGroup(pid int) error {
-	proc, err := os.FindProcess(pid)
-	if err != nil {
-		return err
-	}
-	return syscall.Kill(-proc.Pid, syscall.SIGKILL)
-}
-
 // destroyPlugin kills the plugin with the given pid and also kills the user
 // process
 func destroyPlugin(pluginPid int, userPid int) error {