Split out parent and child listeners into methods

letsencrypt/client/standalone_authenticator.py

@@ -238,7 +238,6 @@ class StandaloneAuthenticator(object):
         self.subproc_inuse = False
         self.subproc_cantbind = False
         self.tasks = {}
-        self.which = None
         self.sock = None
         self.connection = None
         self.private_key = None
@@ -311,19 +310,10 @@ class StandaloneAuthenticator(object):
         new_ctx.use_privatekey(self.private_key)
         connection.set_context(new_ctx)
 
-    def start_listener(self, port, key):
-        """Create a child process which will start a TCP listener on the
-        specified port to perform the specified DVSNI challenges.
+    def do_parent_process(self, port):
+        """Perform the parent process side of the TCP listener task.  This
+        should only be called by start_listener()."""
 
-        :param int port: The TCP port to bind.
-        :param str key: The private key to use (in PEM format).
-        """
-        fork_result = os.fork()
-        Crypto.Random.atfork()
-        if fork_result:
-            # PARENT process (still the Let's Encrypt client process)
-            self.which = "parent"
-            self.child_pid = fork_result
         signal.signal(signal.SIGIO, self.client_signal_handler)
         signal.signal(signal.SIGUSR1, self.client_signal_handler)
         signal.signal(signal.SIGUSR2, self.client_signal_handler)
@@ -350,10 +340,10 @@ class StandaloneAuthenticator(object):
             "Subprocess unexpectedly timed out while trying to bind TCP "
             "port {}.".format(CONFIG.PORT))
         return False
-        else:
-            # CHILD process (the TCP listener subprocess)
-            self.which = "child"
-            self.child_pid = os.getpid()
+
+    def do_child_process(self, port, key):
+        """Perform the child process side of the TCP listener task.  This
+        should only be called by start_listener()."""
         signal.signal(signal.SIGINT, self.subproc_signal_handler)
         self.sock = socket.socket()
         try:
@@ -423,6 +413,24 @@ class StandaloneAuthenticator(object):
             # self.connection.send(tls_generate_server_hello_done())
             # self.connection.close()
 
+    def start_listener(self, port, key):
+        """Create a child process which will start a TCP listener on the
+        specified port to perform the specified DVSNI challenges.
+
+        :param int port: The TCP port to bind.
+        :param str key: The private key to use (in PEM format).
+        """
+        fork_result = os.fork()
+        Crypto.Random.atfork()
+        if fork_result:
+            # PARENT process (still the Let's Encrypt client process)
+            self.child_pid = fork_result
+            self.do_parent_process(port)
+        else:
+            # CHILD process (the TCP listener subprocess)
+            self.child_pid = os.getpid()
+            self.do_child_process(port, key)
+
     # IAuthenticator method implementations follow
 
     def get_chall_pref(self, unused_domain):