Fix OSError from os.getlogin() (RhBug:1251352)

Inspired by RhBug:843434

tracer/controllers/default.py

@@ -119,5 +119,5 @@ def _restartable_applications(self, applications, args):
 
 	def _user(self, user):
 		if   user == '*':    return None
-		elif not user:       return os.getlogin()
+		elif not user:       return System.user()
 		else: return user[0]

tracer/controllers/resource.py

@@ -80,7 +80,6 @@ def render_system(self):
 		uptime = str(uptime).split('.')[0]
 
 		users = set([user.name for user in psutil.get_users()])
-		user = os.getlogin()
 		package_managers = System.package_manager().names()
 
 		view = SystemView()
@@ -89,7 +88,7 @@ def render_system(self):
 		view.assign('package_managers', package_managers)
 		view.assign('init', System.init_system())
 		view.assign('uptime', uptime)
-		view.assign('user', user)
+		view.assign('user', System.user())
 		view.assign('users', users)
 		view.assign('version', __version__)
 		view.assign('rules_count', len(Rules.all()))

tracer/paths.py

@@ -19,6 +19,7 @@
 
 import os
 from os.path import dirname, realpath, expanduser
+from tracer.resources.system import System
 
 
 def __(paths):
@@ -49,7 +50,8 @@ def __(paths):
 ])
 
 try:
-	USER_CONFIG_DIRS.append(expanduser('~' + os.getlogin()) + '/.config/tracer')
-	HOOKS_DIRS.append(expanduser('~' + os.getlogin()) + '/.config/tracer/hooks')
+	user = System.user()
+	USER_CONFIG_DIRS.append(expanduser('~' + user) + '/.config/tracer')
+	HOOKS_DIRS.append(expanduser('~' + user) + '/.config/tracer/hooks')
 except OSError:
 	pass

tracer/resources/applications.py

@@ -24,6 +24,7 @@
 from tracer.resources.collections import ApplicationsCollection
 from tracer.resources.lang import _
 from tracer.resources.processes import Processes
+from tracer.resources.system import System
 import os
 import re
 
@@ -190,7 +191,7 @@ def has_service_file(self):
 	@property
 	def helper(self):
 		helper = self._attributes["helper"] if self._attributes["helper"] else Applications._helper(self)
-		if os.getlogin() != "root" and self.type == Applications.TYPES["DAEMON"]:
+		if System.user() != "root" and self.type == Applications.TYPES["DAEMON"]:
 			if helper and not helper.startswith("sudo "):
 				helper = "sudo " + helper
 		return helper

tracer/resources/system.py

@@ -21,6 +21,8 @@
 from __future__ import absolute_import
 
 # WARNING: There are imports in package_manager()
+import os
+import pwd
 import importlib
 import platform
 import psutil
@@ -81,3 +83,10 @@ def boot_time():
 	@staticmethod
 	def python_version():
 		return "{}.{}.{}".format(version_info.major, version_info.minor, version_info.micro)
+
+	@staticmethod
+	def user():
+		# getlogin is prefered because it return current username even
+		# if python process is executed with sudo
+		try: return os.getlogin()
+		except OSError: return pwd.getpwuid(os.getuid())[0]