Merge ~jocave/plainbox:dot-username-rootctrl into plainbox:master

[Jonathan Cave]

The RootViaSudoExecutionController tries to establish that a user running tests from a checkbox snap has ability to sudo by, amongst other things, testing if there is a file matching /etc/sudoers.d/create-user-<USERNAME>

However, the snapd code itself replaces '.' characters in the user name with %2E (see the link in the comment in the code).

This updates the plainbox code to do the same.

Tested as working on hohhot.

[Sylvain Pineau (sylvain-pineau)]

Good catch, thanks for the fix

review: Approve

diff --git a/plainbox/impl/ctrl.py b/plainbox/impl/ctrl.py
index 75c4332..6666e33 100644
--- a/plainbox/impl/ctrl.py
+++ b/plainbox/impl/ctrl.py
@@ -1453,9 +1453,14 @@ class RootViaSudoExecutionController(
         # On snappy, the group check does not work. Let's verify if snap
         # create-user made a rule for the current user
         in_sudoers_d = False
+        # NOTE Sept 2017: snapd currently explicitly handles '.' chars in the
+        # username by replacing with %2E
+        # https://github.com/snapcore/snapd/blob/master/osutil/user.go#L84
+        # Hence doing the same here:
+        user_mod = os.getenv('USER').replace('.', '%2E')
         if (os.getenv("SNAP")):
             in_sudoers_d = os.path.exists(
-                '/etc/sudoers.d/create-user-{}'.format(os.getenv('USER')))
+                '/etc/sudoers.d/create-user-{}'.format(user_mod))
         self.user_can_sudo = in_sudo_group or in_admin_group or in_sudoers_d
         self.warm_up_func = lambda: extcmd.ExternalCommand().call(
             ['sudo', '-S', 'true'])