Issue #20037: Avoid crashes when doing text I/O late at interpreter shutdown.

6 files changed, 33 insertions, 7 deletions

diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 9866fbe82b..be0464c4fa 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -539,6 +539,20 @@ _PyIO_ConvertSsize_t(PyObject *obj, void *result) {
 }
 
 
+_PyIO_State *
+_PyIO_get_module_state(void)
+{
+    PyObject *mod = PyState_FindModule(&_PyIO_Module);
+    _PyIO_State *state;
+    if (mod == NULL || (state = IO_MOD_STATE(mod)) == NULL) {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "could not find io module state "
+                        "(interpreter shutdown?)");
+        return NULL;
+    }
+    return state;
+}
+
 PyObject *
 _PyIO_get_locale_module(_PyIO_State *state)
 {
diff --git a/Modules/_io/_iomodule.h b/Modules/_io/_iomodule.h
index b90a658397..8927864e8c 100644
--- a/Modules/_io/_iomodule.h
+++ b/Modules/_io/_iomodule.h
@@ -135,8 +135,9 @@ typedef struct {
 } _PyIO_State;
 
 #define IO_MOD_STATE(mod) ((_PyIO_State *)PyModule_GetState(mod))
-#define IO_STATE IO_MOD_STATE(PyState_FindModule(&_PyIO_Module))
+#define IO_STATE() _PyIO_get_module_state()
 
+extern _PyIO_State *_PyIO_get_module_state(void);
 extern PyObject *_PyIO_get_locale_module(_PyIO_State *);
 
 extern PyObject *_PyIO_str_close;
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index a04b48dd3a..34c2bb97bd 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -91,7 +91,9 @@ bufferediobase_readinto(PyObject *self, PyObject *args)
 static PyObject *
 bufferediobase_unsupported(const char *message)
 {
-    PyErr_SetString(IO_STATE->unsupported_operation, message);
+    _PyIO_State *state = IO_STATE();
+    if (state != NULL)
+        PyErr_SetString(state->unsupported_operation, message);
     return NULL;
 }
 
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 0e1e709efd..cbb2daf5c2 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -493,8 +493,10 @@ err_closed(void)
 static PyObject *
 err_mode(char *action)
 {
-    PyErr_Format(IO_STATE->unsupported_operation,
-                 "File not open for %s", action);
+    _PyIO_State *state = IO_STATE();
+    if (state != NULL)
+        PyErr_Format(state->unsupported_operation,
+                     "File not open for %s", action);
     return NULL;
 }
 
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index 1b7cb0ff70..e3729902d8 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -69,7 +69,9 @@ _Py_IDENTIFIER(read);
 static PyObject *
 iobase_unsupported(const char *message)
 {
-    PyErr_SetString(IO_STATE->unsupported_operation, message);
+    _PyIO_State *state = IO_STATE();
+    if (state != NULL)
+        PyErr_SetString(state->unsupported_operation, message);
     return NULL;
 }
 
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index fb89a17927..747f62323c 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -45,7 +45,9 @@ PyDoc_STRVAR(textiobase_doc,
 static PyObject *
 _unsupported(const char *message)
 {
-    PyErr_SetString(IO_STATE->unsupported_operation, message);
+    _PyIO_State *state = IO_STATE();
+    if (state != NULL)
+        PyErr_SetString(state->unsupported_operation, message);
     return NULL;
 }
 
@@ -852,7 +854,7 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
     char *errors = NULL;
     char *newline = NULL;
     int line_buffering = 0, write_through = 0;
-    _PyIO_State *state = IO_STATE;
+    _PyIO_State *state = NULL;
 
     PyObject *res;
     int r;
@@ -891,6 +893,9 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
     if (encoding == NULL) {
         /* Try os.device_encoding(fileno) */
         PyObject *fileno;
+        state = IO_STATE();
+        if (state == NULL)
+            goto error;
         fileno = _PyObject_CallMethodId(buffer, &PyId_fileno, NULL);
         /* Ignore only AttributeError and UnsupportedOperation */
         if (fileno == NULL) {