Start a sandbox process in a new userns only if CAP_SETUID is set

In addition, it fixes a race condition in TestMultiContainerGoferStop.
There are two scripts copy the same set of files into the same directory
and sometime one of this command fails with EXIST.

PiperOrigin-RevId: 230011247
Change-Id: I9289f72e65dc407cdcd0e6cd632a509e01f43e9c

1 files changed, 6 insertions, 5 deletions

diff --git a/runsc/container/multi_container_test.go b/runsc/container/multi_container_test.go
index 8490999ea..8922e6dbe 100644
--- a/runsc/container/multi_container_test.go
+++ b/runsc/container/multi_container_test.go
@@ -739,11 +739,6 @@ func TestMultiContainerGoferStop(t *testing.T) {
 		t.Fatal("error finding test_app:", err)
 	}
 
-	dir, err := ioutil.TempDir(testutil.TmpDir(), "gofer-stop-test")
-	if err != nil {
-		t.Fatal("ioutil.TempDir failed:", err)
-	}
-
 	// Setup containers. Root container just reaps children, while the others
 	// perform some IOs. Children are executed in 3 batches of 10. Within the
 	// batch there is overlap between containers starting and being destroyed. In
@@ -751,6 +746,12 @@ func TestMultiContainerGoferStop(t *testing.T) {
 	cmds := [][]string{{app, "reaper"}}
 	const batchSize = 10
 	for i := 0; i < 3*batchSize; i++ {
+		dir, err := ioutil.TempDir(testutil.TmpDir(), "gofer-stop-test")
+		if err != nil {
+			t.Fatal("ioutil.TempDir failed:", err)
+		}
+		defer os.RemoveAll(dir)
+
 		cmd := "find /bin -type f | head | xargs -I SRC cp SRC " + dir
 		cmds = append(cmds, []string{"sh", "-c", cmd})
 	}