bpo-41818: Add termios.tcgetwinsize(), termios.tcsetwinsize(). Update docs.

Doc/library/termios.rst

@@ -74,6 +74,19 @@ The module defines the following functions:
    output, :const:`TCIOFF` to suspend input, or :const:`TCION` to restart input.
 
 
+.. function:: tcgetwinsize(fd)
+
+   Return a list ``[ws_row, ws_col]`` containing the tty window size for file
+   descriptor *fd*. Requires :const:`termios.TIOCGWINSZ`.
+
+
+.. function:: tcsetwinsize(fd, winsize)
+
+    Set the tty window size for file descriptor *fd* from *winsize*, which is
+    a list like the one returned by :func:`tcgetwinsize`. Requires
+    :const:`termios.TIOCGWINSZ` and :const:`termios.TIOCSWINSZ`.
+
+
 .. seealso::
 
    Module :mod:`tty`

Misc/NEWS.d/next/Library/2020-12-08-01-08-58.bpo-41818.zO8vV7.rst

@@ -0,0 +1 @@
+Soumendra Ganguly: add termios.tcgetwinsize(), termios.tcsetwinsize().

Modules/termios.c

@@ -315,6 +315,96 @@ termios_tcflow_impl(PyObject *module, int fd, int action)
     Py_RETURN_NONE;
 }
 
+/*[clinic input]
+termios.tcgetwinsize
+
+    fd: fildes
+    /
+
+Get the tty winsize for file descriptor fd.
+
+Returns a list [ws_row, ws_col].
+[clinic start generated code]*/
+
+static PyObject *
+termios_tcgetwinsize_impl(PyObject *module, int fd)
+/*[clinic end generated code: output=31825977d5325fb6 input=c7ed8aa957d108c0]*/
+{
+#if defined(TIOCGWINSZ)
+    termiosmodulestate *state = PyModule_GetState(module);
+    struct winsize w;
+    if (ioctl(fd, TIOCGWINSZ, &w) == -1) {
+        return PyErr_SetFromErrno(state->TermiosError);
+    }
+
+    PyObject *v;
+    if (!(v = PyList_New(2))) {
+        return NULL;
+    }
+
+    PyList_SetItem(v, 0, PyLong_FromLong((long)w.ws_row));
+    PyList_SetItem(v, 1, PyLong_FromLong((long)w.ws_col));
+    if (PyErr_Occurred()) {
+        Py_DECREF(v);
+        return NULL;
+    }
+    return v;
+#else
+    PyErr_SetString(PyExc_NotImplementedError, "termios.TIOCGWINSZ undefined");
+    return NULL;
+#endif /* defined(TIOCGWINSZ) */
+}
+
+/*[clinic input]
+termios.tcsetwinsize
+
+    fd: fildes
+    winsize as winsz: object
+    /
+
+Set the tty winsize for file descriptor fd.
+
+The winsize to be set is taken from the winsize argument, which
+is a list like the one returned by tcgetwinsize().
+[clinic start generated code]*/
+
+static PyObject *
+termios_tcsetwinsize_impl(PyObject *module, int fd, PyObject *winsz)
+/*[clinic end generated code: output=2ac3c9bb6eda83e1 input=c495180b2b932a30]*/
+{
+#if defined(TIOCGWINSZ) && defined(TIOCSWINSZ)
+    if (!PyList_Check(winsz) || PyList_Size(winsz) != 2) {
+        PyErr_SetString(PyExc_TypeError,
+                     "tcsetwinsize, arg 2: must be 2 element list");
+        return NULL;
+    }
+
+    termiosmodulestate *state = PyModule_GetState(module);
+    struct winsize w;
+    /* Get the old winsize, in case there are
+       more fields such as xpixel, ypixel */
+    if (ioctl(fd, TIOCGWINSZ, &w) == -1) {
+        return PyErr_SetFromErrno(state->TermiosError);
+    }
+
+    w.ws_row = (unsigned short) PyLong_AsLong(PyList_GetItem(winsz, 0));
+    w.ws_col = (unsigned short) PyLong_AsLong(PyList_GetItem(winsz, 1));
+    if (PyErr_Occurred()) {
+        return NULL;
+    }
+
+    if (ioctl(fd, TIOCSWINSZ, &w) == -1) {
+        return PyErr_SetFromErrno(state->TermiosError);
+    }
+
+    Py_RETURN_NONE;
+#else
+    PyErr_SetString(PyExc_NotImplementedError,
+                    "termios.TIOCGWINSZ and/or termios.TIOCSWINSZ undefined");
+    return NULL;
+#endif /* defined(TIOCGWINSZ) && defined(TIOCSWINSZ) */
+}
+
 static PyMethodDef termios_methods[] =
 {
     TERMIOS_TCGETATTR_METHODDEF
@@ -323,6 +413,8 @@ static PyMethodDef termios_methods[] =
     TERMIOS_TCDRAIN_METHODDEF
     TERMIOS_TCFLUSH_METHODDEF
     TERMIOS_TCFLOW_METHODDEF
+    TERMIOS_TCGETWINSIZE_METHODDEF
+    TERMIOS_TCSETWINSIZE_METHODDEF
     {NULL, NULL}
 };