Mac: Consolidate methods of listing processes

This also updates all other plugins that rely on process listing
and theoretically allows them to choose their preferred method of
process listing.  At the moment, the default (first in the method list)
is chosen.  An optional pslist_method StringRequirement can be added to
each plugin, but using the list in the requirements could break if the
pslist plugin is too old (ie, using the list would happen before the
PluginRequirement gets checked).

If this is a feature we want, it should be easy to add to all but
netstat, which does not parameterize the list of processes.

volatility/framework/plugins/mac/netstat.py

@@ -11,7 +11,7 @@ from volatility.framework.configuration import requirements
 from volatility.framework.interfaces import plugins
 from volatility.framework.objects import utility
 from volatility.framework.renderers import format_hints
-from volatility.plugins.mac import tasks
+from volatility.plugins.mac import pslist
 
 vollog = logging.getLogger(__name__)
 
@@ -26,7 +26,7 @@ class Netstat(plugins.PluginInterface):
                                                      description = 'Kernel Address Space',
                                                      architectures = ["Intel32", "Intel64"]),
             requirements.SymbolTableRequirement(name = "darwin", description = "Mac Kernel"),
-            requirements.PluginRequirement(name = 'tasks', plugin = tasks.Tasks, version = (1, 0, 0))
+            requirements.PluginRequirement(name = 'pslist', plugin = pslist.PsList, version = (2, 0, 0))
         ]
 
     @classmethod
@@ -45,7 +45,9 @@ class Netstat(plugins.PluginInterface):
                 2) The process ID of the processed that opened the socket
                 3) The address of the associated socket structure
         """
-        for task in tasks.Tasks.list_tasks(context, layer_name, darwin_symbols, filter_func):
+        # This is hardcoded, since a change in method
+        list_tasks = pslist.PsList.get_list_tasks(pslist.PsList.pslist_methods[0])
+        for task in list_tasks(context, layer_name, darwin_symbols, filter_func):
 
             task_name = utility.array_to_string(task.p_comm)
             pid = task.p_pid
@@ -67,7 +69,7 @@ class Netstat(plugins.PluginInterface):
                 yield task_name, pid, socket
 
     def _generator(self):
-        filter_func = tasks.Tasks.create_pid_filter([self.config.get('pid', None)])
+        filter_func = pslist.PsList.create_pid_filter([self.config.get('pid', None)])
 
         for task_name, pid, socket in self.list_sockets(self.context,
                                                         self.config['primary'],