Handle socket protocol and service names according to PEP 383

diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -3316,13 +3316,20 @@ for a host.  The host argument is a stri
 static PyObject *
 socket_getservbyname(PyObject *self, PyObject *args)
 {
+    PyObject *nameobj, *protoobj = NULL;
     char *name, *proto=NULL;
     struct servent *sp;
-    if (!PyArg_ParseTuple(args, "s|s:getservbyname", &name, &proto))
+    if (!PyArg_ParseTuple(args, "O&|O&:getservbyname",
+                          PyUnicode_FSConverter, &nameobj,
+                          PyUnicode_FSConverter, &protoobj))
         return NULL;
+    name = PyBytes_AS_STRING(nameobj);
+    proto = protoobj ? PyBytes_AS_STRING(protoobj) : NULL;
     Py_BEGIN_ALLOW_THREADS
     sp = getservbyname(name, proto);
     Py_END_ALLOW_THREADS
+    Py_DECREF(nameobj);
+    Py_XDECREF(protoobj);
     if (sp == NULL) {
         PyErr_SetString(socket_error, "service/proto not found");
         return NULL;
@@ -3347,10 +3354,13 @@ static PyObject *
 socket_getservbyport(PyObject *self, PyObject *args)
 {
     int port;
+    PyObject *protoobj = NULL;
     char *proto=NULL;
     struct servent *sp;
-    if (!PyArg_ParseTuple(args, "i|s:getservbyport", &port, &proto))
+    if (!PyArg_ParseTuple(args, "i|O&:getservbyport",
+                          &port, PyUnicode_FSConverter, &protoobj))
         return NULL;
+    proto = protoobj ? PyBytes_AS_STRING(protoobj) : NULL;
     if (port < 0 || port > 0xffff) {
         PyErr_SetString(
             PyExc_OverflowError,
@@ -3360,11 +3370,12 @@ socket_getservbyport(PyObject *self, PyO
     Py_BEGIN_ALLOW_THREADS
     sp = getservbyport(htons((short)port), proto);
     Py_END_ALLOW_THREADS
+    Py_XDECREF(protoobj);
     if (sp == NULL) {
         PyErr_SetString(socket_error, "port/proto not found");
         return NULL;
     }
-    return PyUnicode_FromString(sp->s_name);
+    return PyUnicode_DecodeFSDefault(sp->s_name);
 }
 
 PyDoc_STRVAR(getservbyport_doc,
@@ -3382,13 +3393,17 @@ otherwise any protocol will match.");
 static PyObject *
 socket_getprotobyname(PyObject *self, PyObject *args)
 {
+    PyObject *nameobj;
     char *name;
     struct protoent *sp;
-    if (!PyArg_ParseTuple(args, "s:getprotobyname", &name))
+    if (!PyArg_ParseTuple(args, "O&:getprotobyname",
+                          PyUnicode_FSConverter, &nameobj))
         return NULL;
+    name = PyBytes_AS_STRING(nameobj);
     Py_BEGIN_ALLOW_THREADS
     sp = getprotobyname(name);
     Py_END_ALLOW_THREADS
+    Py_DECREF(nameobj);
     if (sp == NULL) {
         PyErr_SetString(socket_error, "protocol not found");
         return NULL;
@@ -4002,7 +4017,7 @@ socket_getnameinfo(PyObject *self, PyObj
         set_gaierror(error);
         goto fail;
     }
-    ret = Py_BuildValue("ss", hbuf, pbuf);
+    ret = Py_BuildValue("sN", hbuf, PyUnicode_DecodeFSDefault(pbuf));
 
 fail:
     if (res)