From 2f2dd3fd1a474d01c7bb189a73c0a96702c87ca4 Mon Sep 17 00:00:00 2001
From: Aleksey Lim <alsroot@sugarlabs.org>
Date: Fri, 19 Apr 2013 20:26:49 +0000
Subject: Reset c-ares resolver on network reconnection

---
diff --git a/sugar_network/client/commands.py b/sugar_network/client/commands.py
index d9c89be..a81a91c 100644
--- a/sugar_network/client/commands.py
+++ b/sugar_network/client/commands.py
@@ -329,8 +329,7 @@ class ClientCommands(db.CommandsProcessor, Commands, journal.Commands):
                 while coroutine.select([monitor.fileno()], [], [], 1)[0]:
                     monitor.read()
                 self._node_job.kill()
-                # Otherwise, `socket.gethostbyname()` will return stale resolve
-                util.res_init()
+                coroutine.reset_resolver()
 
     def _remote_connect(self):
 
diff --git a/sugar_network/toolkit/coroutine.py b/sugar_network/toolkit/coroutine.py
index 0c40fac..64b7cf5 100644
--- a/sugar_network/toolkit/coroutine.py
+++ b/sugar_network/toolkit/coroutine.py
@@ -47,6 +47,10 @@ def shutdown():
     return _group.join()
 
 
+def reset_resolver():
+    gevent.get_hub().resolver = None
+
+
 def socket(*args, **kwargs):
     import gevent.socket
     return gevent.socket.socket(*args, **kwargs)
diff --git a/sugar_network/toolkit/util.py b/sugar_network/toolkit/util.py
index 35d37d6..3c1ffc9 100644
--- a/sugar_network/toolkit/util.py
+++ b/sugar_network/toolkit/util.py
@@ -175,25 +175,6 @@ def readline(stream, limit=None):
     return bytes(line)
 
 
-def res_init():
-    """Reset resolving cache.
-
-    Calling this function will enforce libc to avoid using stale resolving
-    cache after getting [re]connected. For example, if application process
-    was launched when there were no any DNS servers available, after getting
-    connected, call `res_init()` to reuse newly appeared DNS servers.
-
-    """
-    import ctypes
-    from ctypes.util import find_library
-    try:
-        lib_name = find_library('c')
-        libc = ctypes.CDLL(lib_name)
-        getattr(libc, '__res_init')(None)
-    except Exception:
-        _logger.exception('Failed to call res_init()')
-
-
 def default_route_exists():
     with file('/proc/self/net/route') as f:
         # Skip header
--
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