Refactor utils/tmpdir.go, fixes #11905

Signed-off-by: Antonio Murdaca <me@runcom.ninja>

daemon/daemon.go

@@ -857,8 +857,8 @@ func NewDaemonFromDirectory(config *Config, eng *engine.Engine) (*Daemon, error)
 		return nil, err
 	}
 
-	// set up the TempDir to use a canonical path
-	tmp, err := utils.TempDir(config.Root)
+	// set up the tmpDir to use a canonical path
+	tmp, err := tempDir(config.Root)
 	if err != nil {
 		return nil, fmt.Errorf("Unable to get the TempDir under %s: %s", config.Root, err)
 	}
@@ -1246,6 +1246,16 @@ func (daemon *Daemon) ImageGetCached(imgID string, config *runconfig.Config) (*i
 	return match, nil
 }
 
+// tempDir returns the default directory to use for temporary files.
+func tempDir(rootDir string) (string, error) {
+	var tmpDir string
+	if tmpDir = os.Getenv("DOCKER_TMPDIR"); tmpDir == "" {
+		tmpDir = filepath.Join(rootDir, "tmp")
+	}
+	err := os.MkdirAll(tmpDir, 0700)
+	return tmpDir, err
+}
+
 func checkKernel() error {
 	// Check for unsupported kernel versions
 	// FIXME: it would be cleaner to not test for specific versions, but rather

utils/tmpdir.go

@@ -1,16 +0,0 @@
-package utils
-
-import (
-	"os"
-	"path/filepath"
-)
-
-// TempDir returns the default directory to use for temporary files.
-func TempDir(rootDir string) (string, error) {
-	var tmpDir string
-	if tmpDir = os.Getenv("DOCKER_TMPDIR"); tmpDir == "" {
-		tmpDir = filepath.Join(rootDir, "tmp")
-	}
-	err := os.MkdirAll(tmpDir, 0700)
-	return tmpDir, err
-}