From df39686c935f2a6a2cde59db8607c7f7855fd286 Mon Sep 17 00:00:00 2001
From: Andrey Vagin <avagin@openvz.org>
Date: Tue, 8 Sep 2015 12:02:08 +0300
Subject: [PATCH] c/r: create cgroups to restore a container

Here are two reasons:
* If we use systemd, we need to ask it to create cgroups
* If a container is restored with another ID, we need to
  change paths to cgroups.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
---
 libcontainer/container_linux.go | 36 ++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/libcontainer/container_linux.go b/libcontainer/container_linux.go
index 9210ec6a..79d41768 100644
--- a/libcontainer/container_linux.go
+++ b/libcontainer/container_linux.go
@@ -411,7 +411,7 @@ func (c *linuxContainer) Checkpoint(criuOpts *CriuOpts) error {
 		return err
 	}
 
-	err = c.criuSwrk(nil, req, criuOpts)
+	err = c.criuSwrk(nil, req, criuOpts, false)
 	if err != nil {
 		return err
 	}
@@ -504,6 +504,7 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
 			FileLocks:      proto.Bool(criuOpts.FileLocks),
 		},
 	}
+
 	for _, m := range c.config.Mounts {
 		switch m.Device {
 		case "bind":
@@ -561,14 +562,36 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
 		}
 	}
 
-	err = c.criuSwrk(process, req, criuOpts)
+	err = c.criuSwrk(process, req, criuOpts, true)
 	if err != nil {
 		return err
 	}
 	return nil
 }
 
-func (c *linuxContainer) criuSwrk(process *Process, req *criurpc.CriuReq, opts *CriuOpts) error {
+func (c *linuxContainer) criuApplyCgroups(pid int, req *criurpc.CriuReq) error {
+	if err := c.cgroupManager.Apply(pid); err != nil {
+		return err
+	}
+
+	path := fmt.Sprintf("/proc/%d/cgroup", pid)
+	cgroupsPaths, err := cgroups.ParseCgroupFile(path)
+	if err != nil {
+		return err
+	}
+
+	for c, p := range cgroupsPaths {
+		cgroupRoot := &criurpc.CgroupRoot{
+			Ctrl: proto.String(c),
+			Path: proto.String(p),
+		}
+		req.Opts.CgRoot = append(req.Opts.CgRoot, cgroupRoot)
+	}
+
+	return nil
+}
+
+func (c *linuxContainer) criuSwrk(process *Process, req *criurpc.CriuReq, opts *CriuOpts, applyCgroups bool) error {
 	fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_SEQPACKET|syscall.SOCK_CLOEXEC, 0)
 	if err != nil {
 		return err
@@ -602,6 +625,13 @@ func (c *linuxContainer) criuSwrk(process *Process, req *criurpc.CriuReq, opts *
 		}
 	}()
 
+	if applyCgroups {
+		err := c.criuApplyCgroups(cmd.Process.Pid, req)
+		if err != nil {
+			return err
+		}
+	}
+
 	var extFds []string
 	if process != nil {
 		extFds, err = getPipeFds(cmd.Process.Pid)