gh-117657: Use critical section to make _socket.socket.close thread safe (GH-120490)

Author: aisk

Modules/clinic/socketmodule.c.h

@@ -3331,8 +3331,19 @@ sockets the address is a tuple (ifname, proto [,pkttype [,hatype [,addr]]])");
    Set the file descriptor to -1 so operations tried subsequently
    will surely fail. */
 
+/*[clinic input]
+@critical_section
+_socket.socket.close
+    self as s: self(type="PySocketSockObject *")
+
+close()
+
+Close the socket.  It cannot be used after this call.
+[clinic start generated code]*/
+
 static PyObject *
-sock_close(PySocketSockObject *s, PyObject *Py_UNUSED(ignored))
+_socket_socket_close_impl(PySocketSockObject *s)
+/*[clinic end generated code: output=038b2418e07f6f6c input=9839a261e05bcb97]*/
 {
     SOCKET_T fd;
     int res;
@@ -3357,11 +3368,6 @@ sock_close(PySocketSockObject *s, PyObject *Py_UNUSED(ignored))
     Py_RETURN_NONE;
 }
 
-PyDoc_STRVAR(sock_close_doc,
-"close()\n\
-\n\
-Close the socket.  It cannot be used after this call.");
-
 static PyObject *
 sock_detach(PySocketSockObject *s, PyObject *Py_UNUSED(ignored))
 {
@@ -5118,8 +5124,7 @@ static PyMethodDef sock_methods[] = {
     {"bind",              (PyCFunction)sock_bind, METH_O,
                       bind_doc},
 #endif
-    {"close",             (PyCFunction)sock_close, METH_NOARGS,
-                      sock_close_doc},
+    _SOCKET_SOCKET_CLOSE_METHODDEF
 #ifdef HAVE_CONNECT
     {"connect",           (PyCFunction)sock_connect, METH_O,
                       connect_doc},

Modules/socketmodule.c

@@ -54,7 +54,6 @@ race_top:PyInterpreterState_ThreadHead
 race_top:_PyObject_TryGetInstanceAttribute
 race_top:PyThreadState_Next
 race_top:PyUnstable_InterpreterFrame_GetLine
-race_top:sock_close
 race_top:tstate_delete_common
 race_top:tstate_is_freed
 race_top:type_modified_unlocked