runtime: integrate escape route for applications without ADF support

the select_parent method in RuntimeLchan currently implements a way
to escape from an application that has no filesystem support. However,
this escape route can be integrated directly into the select_file
method. This will give us the benefit that it will work transparently
in all code locations.

(This also means we can get rid of the select_parent method again)

Related: OS#6120
Change-Id: Ie6f37d13af880d24a9c7a8a95cef436b603587c7

pySim-shell.py

@@ -534,7 +534,7 @@ class PySimCommands(CommandSet):
                 # below, so we must not move up.
                 if skip_df == False:
                     self.walk(indent + 1, action_ef, action_df, context, **kwargs)
-                    self._cmd.lchan.select_parent(self._cmd)
+                    self._cmd.lchan.select_file(self._cmd.lchan.selected_file.parent, self._cmd)
 
             elif action_ef:
                 df_before_action = self._cmd.lchan.selected_file

pySim/runtime.py

@@ -320,6 +320,24 @@ class RuntimeLchan:
             file : CardFile [or derived class] instance
             cmd_app : Command Application State (for unregistering old file commands)
         """
+
+        if not isinstance(file, CardADF) and self.selected_adf and self.selected_adf.has_fs == False:
+            # Not every application that may be present on a GlobalPlatform card will support the SELECT
+            # command as we know it from ETSI TS 102 221, section 11.1.1. In fact the only subset of
+            # SELECT we may rely on is the OPEN SELECT command as specified in GlobalPlatform Card
+            # Specification, section 11.9. Unfortunately the OPEN SELECT command only supports the
+            # "select by name" method, which means we can only select an application and not a file.
+            # The consequence of this is that we may get trapped in an application that does not have
+            # ISIM/USIM like file system support and the only way to leave that application is to select
+            # an ISIM/USIM application in order to get the file system access back.
+            #
+            # To automate this escape-route we will first select an arbitrary ADF that has file system support first
+            # and then continue normally.
+            for selectable in self.rs.mf.get_selectables().items():
+                if isinstance(selectable[1], CardADF) and selectable[1].has_fs == True:
+                    self.select(selectable[1].name, cmd_app)
+                    break
+
         # we need to find a path from our self.selected_file to the destination
         inter_path = self.selected_file.build_select_path_to(file)
         if not inter_path:
@@ -394,36 +412,6 @@ class RuntimeLchan:
 
         return self.selected_file_fcp
 
-    def select_parent(self, cmd_app=None):
-        """Select the parent file of the currently selected file. This method also works in case the currently selected
-        file is an ADF without UICC file system support and can be used to exit those ADFs.
-        """
-        parent = self.selected_file.parent
-        df = self.selected_file
-        adf = self.selected_adf
-        if adf and adf.has_fs == False:
-            # Not every application that may be present on a GlobalPlatform card will support the SELECT
-            # command as we know it from ETSI TS 102 221, section 11.1.1. In fact the only subset of
-            # SELECT we may rely on is the OPEN SELECT command as specified in GlobalPlatform Card
-            # Specification, section 11.9. Unfortunately the OPEN SELECT command only supports the
-            # "select by name" method, which means we can only select an application and not a file.
-            # The consequence of this is that we may get trapped in an application that does not have
-            # ISIM/USIM like file system support and the only way to leave that application is to select
-            # an ISIM/USIM application in order to get the file system access back.
-            #
-            # To automate this escape-route while traversing the file system we will check whether
-            # the parent file is the MF. When this is the case and the selected ADF has no file system
-            # support, we will select an arbitrary ADF that has file system support first and from there
-            # we will then select the MF.
-            for selectable in parent.get_selectables().items():
-                if isinstance(selectable[1], CardADF) and selectable[1].has_fs == True:
-                    self.select(selectable[1].name, cmd_app)
-                    break
-            self.select_file(parent, cmd_app)
-
-        # Select the parent file normally
-        self.select_file(parent, cmd_app)
-
     def status(self):
         """Request STATUS (current selected file FCP) from card."""
         (data, _sw) = self.scc.status()