Don't cleanup UNIX server sockets paths when server is closing

Fixes issue #28.

Author: 1st1

tests/test_unix.py

@@ -7,7 +7,7 @@
 
 
 class _TestUnix:
-    def test_create_server_1(self):
+    def test_create_unix_server_1(self):
         CNT = 0           # number of clients that were successful
         TOTAL_CNT = 100   # total number of clients that test will create
         TIMEOUT = 5.0     # timeout for this test
@@ -72,12 +72,16 @@ async def start_server():
                         TIMEOUT, loop=self.loop)
 
                 finally:
-                    srv.close()
+                    self.loop.call_soon(srv.close)
+                    await srv.wait_closed()
 
                     # Check that the server cleaned-up proxy-sockets
                     for srv_sock in srv_socks:
                         self.assertEqual(srv_sock.fileno(), -1)
 
+                # asyncio doesn't cleanup the sock file
+                self.assertTrue(os.path.exists(sock_name))
+
         async def start_server_sock():
             nonlocal CNT
             CNT = 0
@@ -106,18 +110,35 @@ async def start_server_sock():
                         TIMEOUT, loop=self.loop)
 
                 finally:
-                    srv.close()
+                    self.loop.call_soon(srv.close)
+                    await srv.wait_closed()
 
                     # Check that the server cleaned-up proxy-sockets
                     for srv_sock in srv_socks:
                         self.assertEqual(srv_sock.fileno(), -1)
 
+                # asyncio doesn't cleanup the sock file
+                self.assertTrue(os.path.exists(sock_name))
+
         self.loop.run_until_complete(start_server())
         self.assertEqual(CNT, TOTAL_CNT)
 
         self.loop.run_until_complete(start_server_sock())
         self.assertEqual(CNT, TOTAL_CNT)
 
+    def test_create_unix_server_2(self):
+        with tempfile.TemporaryDirectory() as td:
+            sock_name = os.path.join(td, 'sock')
+            with open(sock_name, 'wt') as f:
+                f.write('x')
+
+            with self.assertRaisesRegex(
+                    OSError, "Address '{}' is already in use".format(
+                        sock_name)):
+
+                self.loop.run_until_complete(
+                    self.loop.create_unix_server(object, sock_name))
+
     def test_create_unix_connection_1(self):
         CNT = 0
         TOTAL_CNT = 100

uvloop/loop.pyx

@@ -1441,10 +1441,27 @@ cdef class Loop:
                 raise ValueError(
                     'path and sock can not be specified at the same time')
 
+            # We use Python sockets to create a UNIX server socket because
+            # when UNIX sockets are created by libuv, libuv removes the path
+            # they were bound to.  This is different from asyncio, which
+            # doesn't cleanup the socket path.
+            sock = socket_socket(uv.AF_UNIX)
+
             try:
-                pipe.bind(path)
+                sock.bind(path)
+            except OSError as exc:
+                pipe._close()
+                sock.close()
+                if exc.errno == errno.EADDRINUSE:
+                    # Let's improve the error message by adding
+                    # with what exact address it occurs.
+                    msg = 'Address {!r} is already in use'.format(path)
+                    raise OSError(errno.EADDRINUSE, msg) from None
+                else:
+                    raise
             except:
                 pipe._close()
+                sock.close()
                 raise
 
         else:
@@ -1456,14 +1473,15 @@ cdef class Loop:
                 raise ValueError(
                     'A UNIX Domain Socket was expected, got {!r}'.format(sock))
 
-            try:
-                fileno = os_dup(sock.fileno())
-                pipe.open(sock.fileno())
-            except:
-                pipe._close()
-                raise
+        try:
+            fileno = os_dup(sock.fileno())
+            pipe.open(fileno)
+        except:
+            pipe._close()
+            sock.close()
+            raise
 
-            pipe._attach_fileobj(sock)
+        pipe._attach_fileobj(sock)
 
         try:
             pipe.listen(backlog)