Merge pull request #49111 from jsafrane/nsenter-path-space

pkg/util/mount/BUILD

@@ -29,6 +29,7 @@ go_test(
     name = "go_default_test",
     srcs = [
         "mount_linux_test.go",
+        "nsenter_mount_test.go",
         "safe_format_and_mount_test.go",
     ],
     library = ":go_default_library",

pkg/util/mount/nsenter_mount.go

@@ -201,8 +201,11 @@ func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
 		// It's safer to assume that it's not a mount point.
 		return true, nil
 	}
-	mountTarget := strings.Split(string(out), " ")[0]
-	mountTarget = strings.TrimSuffix(mountTarget, "\n")
+	mountTarget, err := parseFindMnt(string(out))
+	if err != nil {
+		return false, err
+	}
+
 	glog.V(5).Infof("IsLikelyNotMountPoint findmnt output for path %s: %v:", file, mountTarget)
 
 	if mountTarget == file {
@@ -213,6 +216,18 @@ func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
 	return true, nil
 }
 
+// parse output of "findmnt -o target,fstype" and return just the target
+func parseFindMnt(out string) (string, error) {
+	// cut trailing newline
+	out = strings.TrimSuffix(out, "\n")
+	// cut everything after the last space - it's the filesystem type
+	i := strings.LastIndex(out, " ")
+	if i == -1 {
+		return "", fmt.Errorf("error parsing findmnt output, expected at least one space: %q", out)
+	}
+	return out[:i], nil
+}
+
 // DeviceOpened checks if block device in use by calling Open with O_EXCL flag.
 // Returns true if open returns errno EBUSY, and false if errno is nil.
 // Returns an error if errno is any error other than EBUSY.

pkg/util/mount/nsenter_mount_test.go

+// +build linux
+
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package mount
+
+import "testing"
+
+func TestParseFindMnt(t *testing.T) {
+	tests := []struct {
+		input       string
+		target      string
+		expectError bool
+	}{
+		{
+			// standard mount name, e.g. for AWS
+			"/var/lib/kubelet/plugins/kubernetes.io/aws-ebs/mounts/aws/us-east-1d/vol-020f82b0759f72389 ext4\n",
+			"/var/lib/kubelet/plugins/kubernetes.io/aws-ebs/mounts/aws/us-east-1d/vol-020f82b0759f72389",
+			false,
+		},
+		{
+			// mount name with space, e.g. vSphere
+			"/var/lib/kubelet/plugins/kubernetes.io/vsphere-volume/mounts/[datastore1] kubevols/kubernetes-dynamic-pvc-4aacaa9b-6ba5-11e7-8f64-0050569f1b82.vmdk ext2\n",
+			"/var/lib/kubelet/plugins/kubernetes.io/vsphere-volume/mounts/[datastore1] kubevols/kubernetes-dynamic-pvc-4aacaa9b-6ba5-11e7-8f64-0050569f1b82.vmdk",
+			false,
+		},
+		{
+			// hypotetic mount with several spaces
+			"/var/lib/kubelet/plugins/kubernetes.io/vsphere-volume/mounts/[ d a t a s t o r e 1 ] kubevols/kubernetes-dynamic-pvc-4aacaa9b-6ba5-11e7-8f64-0050569f1b82.vmdk ext2\n",
+			"/var/lib/kubelet/plugins/kubernetes.io/vsphere-volume/mounts/[ d a t a s t o r e 1 ] kubevols/kubernetes-dynamic-pvc-4aacaa9b-6ba5-11e7-8f64-0050569f1b82.vmdk",
+			false,
+		},
+		{
+			// invalid output - no filesystem type
+			"/var/lib/kubelet/plugins/kubernetes.io/vsphere-volume/mounts/blabla",
+			"",
+			true,
+		},
+	}
+
+	for i, test := range tests {
+		target, err := parseFindMnt(test.input)
+		if test.expectError && err == nil {
+			t.Errorf("test %d expected error, got nil", i)
+		}
+		if !test.expectError && err != nil {
+			t.Errorf("test %d returned error: %s", i, err)
+		}
+		if target != test.target {
+			t.Errorf("test %d expected %q, got %q", i, test.target, target)
+		}
+	}
+}