Fix copyFileInfo on Windows

The c.chowner function was being ignored. This change makes use of the
supplied chowner and calls Chown() on the file. If no chowner is
specified, we copy over the DACL and owner information from the source.

copy/copy_windows.go

@@ -17,46 +17,61 @@ func getUIDGID(fi os.FileInfo) (uid, gid int) {
 	return 0, 0
 }
 
-func (c *copier) copyFileInfo(fi os.FileInfo, src, name string) error {
-	if err := os.Chmod(name, fi.Mode()); err != nil {
-		return errors.Wrapf(err, "failed to chmod %s", name)
-	}
-
-	// Copy file ownership and ACL
-	// We need SeRestorePrivilege and SeTakeOwnershipPrivilege in order
-	// to restore security info on a file, especially if we're trying to
-	// apply security info which includes SIDs not necessarily present on
-	// the host.
-	privileges := []string{winio.SeRestorePrivilege, seTakeOwnershipPrivilege}
-	if err := winio.EnableProcessPrivileges(privileges); err != nil {
-		return err
-	}
-	defer winio.DisableProcessPrivileges(privileges)
-
+func getFileSecurityInfo(name string) (*windows.SID, *windows.ACL, error) {
 	secInfo, err := windows.GetNamedSecurityInfo(
-		src, windows.SE_FILE_OBJECT,
+		name, windows.SE_FILE_OBJECT,
 		windows.OWNER_SECURITY_INFORMATION|windows.DACL_SECURITY_INFORMATION)
 
 	if err != nil {
-		return err
+		return nil, nil, errors.Wrap(err, "fetching security info")
+	}
+	sid, _, err := secInfo.Owner()
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "fetching owner SID")
 	}
-
 	dacl, _, err := secInfo.DACL()
 	if err != nil {
-		return err
+		return nil, nil, errors.Wrap(err, "fetching dacl")
 	}
+	return sid, dacl, nil
+}
 
-	sid, _, err := secInfo.Owner()
+func (c *copier) copyFileInfo(fi os.FileInfo, src, name string) error {
+	if err := os.Chmod(name, fi.Mode()); err != nil {
+		return errors.Wrapf(err, "failed to chmod %s", name)
+	}
+
+	sid, dacl, err := getFileSecurityInfo(src)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "getting file info")
 	}
 
-	if err := windows.SetNamedSecurityInfo(
-		name, windows.SE_FILE_OBJECT,
-		windows.OWNER_SECURITY_INFORMATION|windows.DACL_SECURITY_INFORMATION,
-		sid, nil, dacl, nil); err != nil {
+	if c.chown != nil {
+		// Use the defined chowner.
+		usr := &User{SID: sid.String()}
+		if err := Chown(name, usr, c.chown); err != nil {
+			return errors.Wrapf(err, "failed to chown %s", name)
+		}
+		return nil
+	} else {
+		// Copy file ownership and ACL from the source file.
+		// We need SeRestorePrivilege and SeTakeOwnershipPrivilege in order
+		// to restore security info on a file, especially if we're trying to
+		// apply security info which includes SIDs not necessarily present on
+		// the host.
+		privileges := []string{winio.SeRestorePrivilege, seTakeOwnershipPrivilege}
+		if err := winio.EnableProcessPrivileges(privileges); err != nil {
+			return err
+		}
+		defer winio.DisableProcessPrivileges(privileges)
 
-		return err
+		if err := windows.SetNamedSecurityInfo(
+			name, windows.SE_FILE_OBJECT,
+			windows.OWNER_SECURITY_INFORMATION|windows.DACL_SECURITY_INFORMATION,
+			sid, nil, dacl, nil); err != nil {
+
+			return err
+		}
 	}
 
 	if err := c.copyFileTimestamp(fi, name); err != nil {