add ansible_executable inventory var

also handle the overrides appropriately
also new executable to set shell type

docsite/rst/intro_configuration.rst

@@ -289,6 +289,8 @@ This indicates the command to use to spawn a shell under a sudo environment.  Us
 
     executable = /bin/bash
 
+Starting in version 2.1 this can be overriden by the inventory var ``ansible_executable``.
+
 .. _filter_plugins:
 
 filter_plugins

docsite/rst/intro_inventory.rst

@@ -231,8 +231,7 @@ SSH connection::
     ansible_ssh_extra_args
       This setting is always appended to the default ssh command line.
     ansible_ssh_pipelining
-      Determines whether or not to use SSH pipelining. This can override the
+      Determines whether or not to use SSH pipelining. This can override the ``pipelining`` setting in ``ansible.cfg``.
-      ``pipelining`` setting in ``ansible.cfg``.
 
 Privilege escalation (see :doc:`Ansible Privilege Escalation<become>` for further details)::
 
@@ -261,6 +260,14 @@ Remote host environment parameters::
       Works for anything such as ruby or perl and works just like ansible_python_interpreter.
       This replaces shebang of modules which will run on that host.
 
+.. versionadded:: 2.1
+
+::
+
+    ansible_executable
+      This sets the shell the ansible controller will use on the target machine, overrides ``executable`` in ``ansible.cfg`` which defaults to '/bin/sh'.
+      You should really only change it if is not possible to use '/bin/sh' (i.e. it is not in the list of allowed shells for your users).
+
 Examples from a host file::
 
   some_host         ansible_port=2222     ansible_user=manager

lib/ansible/playbook/play_context.py

@@ -78,6 +78,7 @@ MAGIC_VARIABLE_MAPPING = dict(
    su_pass          = ('ansible_su_password', 'ansible_su_pass'),
    su_exe           = ('ansible_su_exe',),
    su_flags         = ('ansible_su_flags',),
+   executable       = ('ansible_executable',),
 )
 
 SU_PROMPT_LOCALIZATIONS = [
@@ -163,6 +164,7 @@ class PlayContext(Base):
     _accelerate       = FieldAttribute(isa='bool', default=False)
     _accelerate_ipv6  = FieldAttribute(isa='bool', default=False, always_post_validate=True)
     _accelerate_port  = FieldAttribute(isa='int', default=C.ACCELERATE_PORT, always_post_validate=True)
+    _executable       = FieldAttribute(isa='string', default=C.DEFAULT_EXECUTABLE)
 
     # privilege escalation fields
     _become           = FieldAttribute(isa='bool')
@@ -354,6 +356,12 @@ class PlayContext(Base):
         else:
             delegated_vars = dict()
 
+            # setup shell
+            for exe_var in MAGIC_VARIABLE_MAPPING.get('executable'):
+                if exe_var in variables:
+                    setattr(new_info, 'executable', variables.get(exe_var))
+
+
         attrs_considered = []
         for (attr, variable_names) in iteritems(MAGIC_VARIABLE_MAPPING):
             for variable_name in variable_names:
@@ -417,7 +425,7 @@ class PlayContext(Base):
         self.prompt = None
 
         if executable is None:
-            executable = C.DEFAULT_EXECUTABLE
+            executable = self.executable
 
         if self.become:
 

lib/ansible/plugins/action/__init__.py

@@ -521,7 +521,7 @@ class ActionBase(with_metaclass(ABCMeta, object)):
         display.debug("done with _execute_module (%s, %s)" % (module_name, module_args))
         return data
 
-    def _low_level_execute_command(self, cmd, sudoable=True, in_data=None, executable=C.DEFAULT_EXECUTABLE, encoding_errors='replace'):
+    def _low_level_execute_command(self, cmd, sudoable=True, in_data=None, executable=None, encoding_errors='replace'):
         '''
         This is the function which executes the low level shell command, which
         may be commands to create/remove directories for temporary files, or to
@@ -548,7 +548,9 @@ class ActionBase(with_metaclass(ABCMeta, object)):
             display.debug("_low_level_execute_command(): using become for this command")
             cmd = self._play_context.make_become_cmd(cmd, executable=executable)
 
-        if executable is not None and self._connection.allow_executable:
+        if self._connection.allow_executable:
+            if executable is None:
+                executable = self._play_context.executable
             cmd = executable + ' -c ' + pipes.quote(cmd)
 
         display.debug("_low_level_execute_command(): executing: %s" % (cmd,))

lib/ansible/plugins/connection/__init__.py

@@ -1,4 +1,4 @@
-# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
+
 # (c) 2015 Toshio Kuratomi <tkuratomi@ansible.com>
 #
 # This file is part of Ansible
@@ -89,7 +89,7 @@ class ConnectionBase(with_metaclass(ABCMeta, object)):
             shell_type = getattr(self, '_shell_type')
         else:
             shell_type = 'sh'
-            shell_filename = os.path.basename(C.DEFAULT_EXECUTABLE)
+            shell_filename = os.path.basename(self.play_context.executable)
             for shell in shell_loader.all():
                 if shell_filename in shell.COMPATIBLE_SHELLS:
                     shell_type = shell.SHELL_FAMILY

test/units/plugins/action/test_action.py

@@ -617,8 +617,8 @@ class TestActionBase(unittest.TestCase):
         play_context.make_become_cmd.assert_not_called()
 
         play_context.remote_user = 'apo'
-        action_base._low_level_execute_command('ECHO', sudoable=True)
+        action_base._low_level_execute_command('ECHO', sudoable=True, executable='/bin/csh')
-        play_context.make_become_cmd.assert_called_once_with("ECHO", executable='/bin/sh')
+        play_context.make_become_cmd.assert_called_once_with("ECHO", executable='/bin/csh')
 
         play_context.make_become_cmd.reset_mock()
 
@@ -627,6 +627,6 @@ class TestActionBase(unittest.TestCase):
         try:
             play_context.remote_user = 'root'
             action_base._low_level_execute_command('ECHO SAME', sudoable=True)
-            play_context.make_become_cmd.assert_called_once_with("ECHO SAME", executable='/bin/sh')
+            play_context.make_become_cmd.assert_called_once_with("ECHO SAME", executable=None)
         finally:
             C.BECOME_ALLOW_SAME_USER = become_allow_same_user