From f9a0d21fab682198629e56fbcb404c98ad28ea29 Mon Sep 17 00:00:00 2001
From: Qiang Huang <h.huangqiang@huawei.com>
Date: Thu, 2 Apr 2015 11:00:35 +0800
Subject: [PATCH] cleanup for systemd cgroup

Add join function so we can reduce duplicate code, and we can
call Set api in fs cgroup, that can reduce sync work on fs side
and systemd side.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
---
 cgroups/systemd/apply_systemd.go | 44 +++++++++++++++-----------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/cgroups/systemd/apply_systemd.go b/cgroups/systemd/apply_systemd.go
index a06ad01ed..3609bccae 100644
--- a/cgroups/systemd/apply_systemd.go
+++ b/cgroups/systemd/apply_systemd.go
@@ -3,7 +3,6 @@
 package systemd
 
 import (
-	"bytes"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -247,6 +246,21 @@ func writeFile(dir, file, data string) error {
 	return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
 }
 
+func join(c *configs.Cgroup, subsystem string, pid int) (string, error) {
+	path, err := getSubsystemPath(c, subsystem)
+	if err != nil {
+		return "", err
+	}
+	if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {
+		return "", err
+	}
+	if err := writeFile(path, "cgroup.procs", strconv.Itoa(pid)); err != nil {
+		return "", err
+	}
+
+	return path, nil
+}
+
 func joinCpu(c *configs.Cgroup, pid int) error {
 	path, err := getSubsystemPath(c, "cpu")
 	if err != nil {
@@ -266,16 +280,11 @@ func joinCpu(c *configs.Cgroup, pid int) error {
 }
 
 func joinFreezer(c *configs.Cgroup, pid int) error {
-	path, err := getSubsystemPath(c, "freezer")
-	if err != nil {
+	if _, err := join(c, "freezer", pid); err != nil {
 		return err
 	}
 
-	if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {
-		return err
-	}
-
-	return ioutil.WriteFile(filepath.Join(path, "cgroup.procs"), []byte(strconv.Itoa(pid)), 0700)
+	return nil
 }
 
 func getSubsystemPath(c *configs.Cgroup, subsystem string) (string, error) {
@@ -360,29 +369,16 @@ func getUnitName(c *configs.Cgroup) string {
 // because systemd will re-write the device settings if it needs to re-apply the cgroup context.
 // This happens at least for v208 when any sibling unit is started.
 func joinDevices(c *configs.Cgroup, pid int) error {
-	path, err := getSubsystemPath(c, "devices")
+	path, err := join(c, "devices", pid)
 	if err != nil {
 		return err
 	}
 
-	if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {
+	devices := subsystems["devices"]
+	if err := devices.Set(path, c); err != nil {
 		return err
 	}
 
-	if err := ioutil.WriteFile(filepath.Join(path, "cgroup.procs"), []byte(strconv.Itoa(pid)), 0700); err != nil {
-		return err
-	}
-
-	if !c.AllowAllDevices {
-		if err := writeFile(path, "devices.deny", "a"); err != nil {
-			return err
-		}
-	}
-	for _, dev := range c.AllowedDevices {
-		if err := writeFile(path, "devices.allow", dev.CgroupString()); err != nil {
-			return err
-		}
-	}
 	return nil
 }