Handle SIGINT/SIGTERM in processes.

1 files changed, 30 insertions, 13 deletions

diff --git a/src/leap/bitmask/frontend_app.py b/src/leap/bitmask/frontend_app.py
index 1fe4cd0a..5dc42287 100644
--- a/src/leap/bitmask/frontend_app.py
+++ b/src/leap/bitmask/frontend_app.py
@@ -14,10 +14,13 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
+import multiprocessing
 import signal
 import sys
 import os
 
+from functools import partial
+
 from PySide import QtCore, QtGui
 
 from leap.bitmask.config import flags
@@ -29,15 +32,20 @@ import logging
 logger = logging.getLogger(__name__)
 
 
-def sigint_handler(*args, **kwargs):
+def signal_handler(window, signum, frame):
     """
-    Signal handler for SIGINT
+    Signal handler that quits the running app cleanly.
+
+    :param window: a window with a `quit` callable
+    :type window: MainWindow
+    :param signum: number of the signal received (e.g. SIGINT -> 2)
+    :type signum: int
+    :param frame: current stack frame
+    :type frame: frame or None
     """
-    logger = kwargs.get('logger', None)
-    if logger:
-        logger.debug("SIGINT catched. shutting down...")
-    mainwindow = args[0]
-    mainwindow.quit()
+    pname = multiprocessing.current_process().name
+    logger.debug("{0}: SIGNAL #{1} catched.".format(pname, signum))
+    window.quit()
 
 
 def run_frontend(options, flags_dict):
@@ -79,12 +87,21 @@ def run_frontend(options, flags_dict):
     qApp.setApplicationName("leap")
     qApp.setOrganizationDomain("leap.se")
 
-    MainWindow(start_hidden=start_hidden)
-
-    # sigint_window = partial(sigint_handler, window, logger=logger)
-    # signal.signal(signal.SIGINT, sigint_window)
-    # Ensure that the application quits using CTRL-C
-    signal.signal(signal.SIGINT, signal.SIG_DFL)
+    # HACK:
+    # We need to do some 'python work' once in a while, otherwise, no python
+    # code will be called and the Qt event loop will prevent the signal
+    # handlers for SIGINT/SIGTERM to be called.
+    # see: http://stackoverflow.com/a/4939113/687989
+    timer = QtCore.QTimer()
+    timer.start(500)  # You may change this if you wish.
+    timer.timeout.connect(lambda: None)  # Let the interpreter run each 500 ms.
+
+    window = MainWindow(start_hidden=start_hidden)
+
+    sigterm_handler = partial(signal_handler, window)
+    # ignore SIGINT since app.py takes care of signaling SIGTERM to us.
+    signal.signal(signal.SIGINT, signal.SIG_IGN)
+    signal.signal(signal.SIGTERM, sigterm_handler)
 
     sys.exit(qApp.exec_())