Preserve file permissions during wwctl overlay edit

- Fixes: #1886

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

CHANGELOG.md

@@ -27,6 +27,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fixed sleep/rebooting on error during GRUB boot. #1894
 - Fixed IPMI VLAN configuration. #1892
 - Fixed `wwctl image shell --help` to fit properly within 80 columns.
+- Preserve existing permissions during `wwctl overlay edit`. #1886
 
 ### Changed
 

internal/app/wwctl/overlay/edit/main.go

@@ -111,16 +111,10 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
 		}
 	}
 
-	// try renaming the tempfile to overlayfile first
-	err = os.Rename(tempFile.Name(), overlayFile)
-	if err != nil {
-		// if it fails, which probably means that they exists on different partitions
-		// fallback to data copy
-		wwlog.Debug("Unable to rename temp file: %s to overlay file: %s, try copying the data", tempFile.Name(), overlayFile)
-		cerr := util.CopyFile(tempFile.Name(), overlayFile)
-		if cerr != nil {
-			return fmt.Errorf("unable to copy data from temp file: %s to target file: %s, err: %s", tempFile.Name(), overlayFile, err)
-		}
+	// using CopyFile preserves target file permissions
+	cerr := util.CopyFile(tempFile.Name(), overlayFile)
+	if cerr != nil {
+		return fmt.Errorf("unable to copy data from temp file: %s to target file: %s, err: %s", tempFile.Name(), overlayFile, err)
 	}
 
 	return nil