1 files changed, 55 insertions, 0 deletions
diff --git a/vendor/github.com/coreos/ignition/internal/exec/util/device_alias.go b/vendor/github.com/coreos/ignition/internal/exec/util/device_alias.go
new file mode 100644
index 00000000..0b4b4474
--- /dev/null
+++ b/vendor/github.com/coreos/ignition/internal/exec/util/device_alias.go
@@ -0,0 +1,55 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// 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 util
+
+import (
+	"os"
+	"path/filepath"
+)
+
+const deviceAliasDir = "/dev_aliases"
+
+// DeviceAlias returns the aliased form of the supplied path.
+// Note device paths in ignition are always absolute.
+func DeviceAlias(path string) string {
+	return filepath.Join(deviceAliasDir, filepath.Clean(path))
+}
+
+// CreateDeviceAlias creates a device alias for the supplied path.
+// On success the canonicalized path used as the alias target is returned.
+func CreateDeviceAlias(path string) (string, error) {
+	target, err := filepath.EvalSymlinks(path)
+	if err != nil {
+		return "", err
+	}
+
+	alias := DeviceAlias(path)
+
+	if err := os.Remove(alias); err != nil {
+		if !os.IsNotExist(err) {
+			return "", err
+		}
+
+		if err = os.MkdirAll(filepath.Dir(alias), 0750); err != nil {
+			return "", err
+		}
+	}
+
+	if err = os.Symlink(target, alias); err != nil {
+		return "", err
+	}
+
+	return target, nil
+}