Refactoring and simplification of interrupt handling

Catch SIGINT and ignore it.
Rely on child process to catch SIGINT too and perform orderly shutdown.
Now all shutdowns should go through basically the same path.
Removed obsolete code.

bazarr.py

@@ -6,7 +6,6 @@ import signal
 import subprocess
 import sys
 import time
-import atexit
 
 from bazarr.app.get_args import args
 from bazarr.literals import *
@@ -53,31 +52,16 @@ check_python_version()
 
 dir_name = os.path.dirname(__file__)
 
-
-def end_child_process(ep):
-    try:
-        if os.name != 'nt':
-            try:
-                ep.send_signal(signal.SIGINT)
-            except ProcessLookupError:
-                pass
-        else:
-            import win32api
-            import win32con
-            try:
-                win32api.GenerateConsoleCtrlEvent(win32con.CTRL_C_EVENT, ep.pid)
-            except KeyboardInterrupt:
-                pass
-    except:
-        ep.terminate()
-
-
 def start_bazarr():
     script = [get_python_path(), "-u", os.path.normcase(os.path.join(dir_name, 'bazarr', 'main.py'))] + sys.argv[1:]
     ep = subprocess.Popen(script, stdout=None, stderr=None, stdin=subprocess.DEVNULL)
-    signal.signal(signal.SIGTERM, lambda signal_no, frame: end_child_process(ep))
     print(f"Bazarr starting child process with PID {ep.pid}...")
     return ep
+ 
+
+def terminate_child():
+    print(f"Terminating child process with PID {child_process.pid}")
+    child_process.terminate()
 
 
 def get_stop_status_code(input_file):
@@ -105,8 +89,7 @@ def check_status():
         except Exception as e:
             print('Unable to delete stop file.')
         finally:
-            print(f"Terminating child process with PID {child_process.pid}")
-            child_process.terminate()
+            terminate_child()
             exit_program(status_code)
 
     if os.path.exists(restartfile):
@@ -116,13 +99,26 @@ def check_status():
         except Exception:
             print('Unable to delete restart file.')
         finally:
-            print(f"Terminating child process with PID {child_process.pid}")
-            child_process.terminate()
+            terminate_child()
             print(f"Bazarr is restarting...")
             child_process = start_bazarr()
 
 
+def interrupt_handler(signum, frame):
+    # catch and ignore keyboard interrupt Ctrl-C
+    # the child process Server object will catch SIGINT and perform an orderly shutdown
+    global interrupted
+    if not interrupted:
+        # ignore user hammering Ctrl-C; we heard you the first time!
+        interrupted = True
+        print('Handling keyboard interrupt...')
+    else:
+        print(f"Stop doing that! I heard you the first time!")
+
+
 if __name__ == '__main__':
+    interrupted = False
+    signal.signal(signal.SIGINT, interrupt_handler)
     restartfile = os.path.join(args.config_dir, FILE_RESTART)
     stopfile = os.path.join(args.config_dir, FILE_STOP)
     os.environ[ENV_STOPFILE] = stopfile
@@ -148,5 +144,6 @@ if __name__ == '__main__':
         try:
             time.sleep(5)
         except (KeyboardInterrupt, SystemExit, ChildProcessError):
+            # this code should never be reached, if signal handling is working properly
             print(f'Bazarr exited main script file via keyboard interrupt.')
-            exit_program(EXIT_NORMAL)
+            exit_program(EXIT_INTERRUPT)