Fix cgroup when path is relative

This can happen when 'docker run --cgroup-parent=' flag is set.

PiperOrigin-RevId: 235645559
Change-Id: Ieea3ae66939abadab621053551bf7d62d412e7ee

2 files changed, 6 insertions, 7 deletions

diff --git a/runsc/test/testutil/docker.go b/runsc/test/testutil/docker.go
index 5a92a5835..bce609061 100644
--- a/runsc/test/testutil/docker.go
+++ b/runsc/test/testutil/docker.go
@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
-	"math/rand"
 	"os"
 	"os/exec"
 	"path"
@@ -31,10 +30,6 @@ import (
 	"github.com/kr/pty"
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 func getRuntime() string {
 	r := os.Getenv("RUNSC_RUNTIME")
 	if r == "" {
@@ -162,8 +157,7 @@ type Docker struct {
 // MakeDocker sets up the struct for a Docker container.
 // Names of containers will be unique.
 func MakeDocker(namePrefix string) Docker {
-	suffix := fmt.Sprintf("-%06d", rand.Int())[:7]
-	return Docker{Name: namePrefix + suffix, Runtime: getRuntime()}
+	return Docker{Name: RandomName(namePrefix), Runtime: getRuntime()}
 }
 
 // Create calls 'docker create' with the arguments provided.
diff --git a/runsc/test/testutil/testutil.go b/runsc/test/testutil/testutil.go
index a84530287..79f0a8b6b 100644
--- a/runsc/test/testutil/testutil.go
+++ b/runsc/test/testutil/testutil.go
@@ -461,3 +461,8 @@ func WriteTmpFile(pattern, text string) (string, error) {
 	}
 	return file.Name(), nil
 }
+
+// RandomName create a name with a 6 digit random number appended to it.
+func RandomName(prefix string) string {
+	return fmt.Sprintf("%s-%06d", prefix, rand.Int31n(1000000))
+}