From 644b8f52a81cf5d9d8ae263a82541b738872ca46 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Charles-Fran=C3=A7ois=20Natali?= Date: Thu, 22 May 2014 19:45:39 +0100 Subject: Issue #21455: Add a default backlog to socket.listen(). --- Doc/library/socket.rst | 11 +++++++---- Lib/test/test_socket.py | 9 ++++++--- Misc/NEWS | 2 ++ Modules/socketmodule.c | 22 ++++++++++++---------- 4 files changed, 27 insertions(+), 17 deletions(-) diff --git a/Doc/library/socket.rst b/Doc/library/socket.rst index 1f5a8e0..3a9d611 100644 --- a/Doc/library/socket.rst +++ b/Doc/library/socket.rst @@ -906,12 +906,15 @@ to sockets. On other platforms, the generic :func:`fcntl.fcntl` and :func:`fcntl.ioctl` functions may be used; they accept a socket object as their first argument. -.. method:: socket.listen(backlog) +.. method:: socket.listen([backlog]) - Listen for connections made to the socket. The *backlog* argument specifies the - maximum number of queued connections and should be at least 0; the maximum value - is system-dependent (usually 5), the minimum value is forced to 0. + Enable a server to accept connections. If *backlog* is specified, it must + be at least 0 (if it is lower, it is set to 0); it specifies the number of + unaccepted connections that the system will allow before refusing new + connections. If not specified, a default reasonable value is chosen. + .. versionchanged:: 3.5 + The *backlog* parameter is now optional. .. method:: socket.makefile(mode='r', buffering=None, *, encoding=None, \ errors=None, newline=None) diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py index aed10a7..86cbec7 100644 --- a/Lib/test/test_socket.py +++ b/Lib/test/test_socket.py @@ -1344,10 +1344,13 @@ class GeneralModuleTests(unittest.TestCase): def test_listen_backlog(self): for backlog in 0, -1: - srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as srv: + srv.bind((HOST, 0)) + srv.listen(backlog) + + with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as srv: srv.bind((HOST, 0)) - srv.listen(backlog) - srv.close() + srv.listen() @support.cpython_only def test_listen_backlog_overflow(self): diff --git a/Misc/NEWS b/Misc/NEWS index 79e1505..76006d9 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -84,6 +84,8 @@ Core and Builtins Library ------- +- Issue #21455: Add a default backlog to socket.listen(). + - Issue #21525: Most Tkinter methods which accepted tuples now accept lists too. - Issue #10744: Fix PEP 3118 format strings on ctypes objects with a nontrivial diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c index d0149dd..5a2893c 100644 --- a/Modules/socketmodule.c +++ b/Modules/socketmodule.c @@ -121,7 +121,7 @@ getpeername() -- return remote address [*]\n\ getsockname() -- return local address\n\ getsockopt(level, optname[, buflen]) -- get socket options\n\ gettimeout() -- return timeout or None\n\ -listen(n) -- start listening for incoming connections\n\ +listen([n]) -- start listening for incoming connections\n\ recv(buflen[, flags]) -- receive data\n\ recv_into(buffer[, nbytes[, flags]]) -- receive data (into a buffer)\n\ recvfrom(buflen[, flags]) -- receive data and sender\'s address\n\ @@ -2534,14 +2534,16 @@ info is a pair (hostaddr, port)."); /* s.listen(n) method */ static PyObject * -sock_listen(PySocketSockObject *s, PyObject *arg) +sock_listen(PySocketSockObject *s, PyObject *args) { - int backlog; + /* We try to choose a default backlog high enough to avoid connection drops + * for common workloads, yet not too high to limit resource usage. */ + int backlog = Py_MIN(SOMAXCONN, 128); int res; - backlog = _PyLong_AsInt(arg); - if (backlog == -1 && PyErr_Occurred()) + if (!PyArg_ParseTuple(args, "|i:listen", &backlog)) return NULL; + Py_BEGIN_ALLOW_THREADS /* To avoid problems on systems that don't allow a negative backlog * (which doesn't make sense anyway) we force a minimum value of 0. */ @@ -2556,12 +2558,12 @@ sock_listen(PySocketSockObject *s, PyObject *arg) } PyDoc_STRVAR(listen_doc, -"listen(backlog)\n\ +"listen([backlog])\n\ \n\ -Enable a server to accept connections. The backlog argument must be at\n\ -least 0 (if it is lower, it is set to 0); it specifies the number of\n\ +Enable a server to accept connections. If backlog is specified, it must be\n\ +at least 0 (if it is lower, it is set to 0); it specifies the number of\n\ unaccepted connections that the system will allow before refusing new\n\ -connections."); +connections. If not specified, a default reasonable value is chosen."); /* @@ -3795,7 +3797,7 @@ static PyMethodDef sock_methods[] = { {"share", (PyCFunction)sock_share, METH_VARARGS, sock_share_doc}, #endif - {"listen", (PyCFunction)sock_listen, METH_O, + {"listen", (PyCFunction)sock_listen, METH_VARARGS, listen_doc}, {"recv", (PyCFunction)sock_recv, METH_VARARGS, recv_doc}, -- cgit v0.12