From c71d9cd4477ad86323a94bd079cecea3aa680711 Mon Sep 17 00:00:00 2001
From: Adrian Reber <areber@redhat.com>
Date: Wed, 26 Jul 2017 18:05:01 +0000
Subject: [PATCH] criuSwrk: prepare for CRIU VERSION RPC

To use the CRIU VERSION RPC the criuSwrk function is adapted to work
with CriuOpts set to 'nil' as CriuOpts is not required for the VERSION
RPC.

Also do not print c.criuVersion if it is '0' as the first RPC call will
always be the VERSION call and only after that the version will be
known.

Signed-off-by: Adrian Reber <areber@redhat.com>
---
 libcontainer/container_linux.go | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/libcontainer/container_linux.go b/libcontainer/container_linux.go
index 0d085d3b1..a856214a1 100644
--- a/libcontainer/container_linux.go
+++ b/libcontainer/container_linux.go
@@ -1059,7 +1059,14 @@ func (c *linuxContainer) criuSwrk(process *Process, req *criurpc.CriuReq, opts *
 		return err
 	}
 
-	logPath := filepath.Join(opts.WorkDirectory, req.GetOpts().GetLogFile())
+	var logPath string
+	if opts != nil {
+		logPath = filepath.Join(opts.WorkDirectory, req.GetOpts().GetLogFile())
+	} else {
+		// For the VERSION RPC 'opts' is set to 'nil' and therefore
+		// opts.WorkDirectory does not exist. Set logPath to "".
+		logPath = ""
+	}
 	criuClient := os.NewFile(uintptr(fds[0]), "criu-transport-client")
 	criuClientFileCon, err := net.FileConn(criuClient)
 	criuClient.Close()
@@ -1074,7 +1081,11 @@ func (c *linuxContainer) criuSwrk(process *Process, req *criurpc.CriuReq, opts *
 	defer criuServer.Close()
 
 	args := []string{"swrk", "3"}
-	logrus.Debugf("Using CRIU %d at: %s", c.criuVersion, c.criuPath)
+	if c.criuVersion != 0 {
+		// If the CRIU Version is still '0' then this is probably
+		// the initial CRIU run to detect the version. Skip it.
+		logrus.Debugf("Using CRIU %d at: %s", c.criuVersion, c.criuPath)
+	}
 	logrus.Debugf("Using CRIU with following args: %s", args)
 	cmd := exec.Command(c.criuPath, args...)
 	if process != nil {