Python wrapper function to establish controlling tty

Author: kovidgoyal

kitty/child.c

@@ -180,8 +180,27 @@ spawn(PyObject *self UNUSED, PyObject *args) {
     return PyLong_FromLong(pid);
 }
 
+static PyObject*
+establish_controlling_tty(PyObject *self UNUSED, PyObject *args) {
+    const char *ttyname;
+    int stdin_fd, stdout_fd, stderr_fd;
+    if (!PyArg_ParseTuple(args, "siii", &ttyname, &stdin_fd, &stdout_fd, &stderr_fd)) return NULL;
+    int tfd = safe_open(ttyname, O_RDWR, 0);
+    if (tfd == -1) return PyErr_SetFromErrnoWithFilename(PyExc_OSError, ttyname);
+#ifdef TIOCSCTTY
+    // On BSD open() does not establish the controlling terminal
+    if (ioctl(tfd, TIOCSCTTY, 0) == -1) return PyErr_SetFromErrno(PyExc_OSError);
+#endif
+    if (dup2(tfd, stdin_fd) == -1) return PyErr_SetFromErrno(PyExc_OSError);
+    if (dup2(tfd, stdout_fd) == -1) return PyErr_SetFromErrno(PyExc_OSError);
+    if (dup2(tfd, stderr_fd) == -1) return PyErr_SetFromErrno(PyExc_OSError);
+    safe_close(tfd, __FILE__, __LINE__);
+    Py_RETURN_NONE;
+}
+
 static PyMethodDef module_methods[] = {
     METHODB(spawn, METH_VARARGS),
+    METHODB(establish_controlling_tty, METH_VARARGS),
     {NULL, NULL, 0, NULL}        /* Sentinel */
 };
 

kitty/fast_data_types.pyi

@@ -1379,3 +1379,7 @@ def shm_unlink(name: str) -> None:
 
 def sigqueue(pid: int, signal: int, value: int) -> None:
     pass
+
+
+def establish_controlling_tty(ttyname: str, stdin: int, stdout: int, stderr: int) -> None:
+    pass