bpo-40268: Add _PyInterpreterState_GetConfig() (GH-19492)

Don't access PyInterpreterState.config member directly anymore, but
use new functions:

* _PyInterpreterState_GetConfig()
* _PyInterpreterState_SetConfig()
* _Py_GetConfig()

19 files changed, 90 insertions, 64 deletions

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index 2709727..7052228 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -192,6 +192,13 @@ PyAPI_FUNC(void) _PyInterpreterState_SetEvalFrameFunc(
     PyInterpreterState *interp,
     _PyFrameEvalFunction eval_frame);
 
+PyAPI_FUNC(const PyConfig*) _PyInterpreterState_GetConfig(PyInterpreterState *interp);
+
+// Get the configuration of the currrent interpreter.
+// The caller must hold the GIL.
+PyAPI_FUNC(const PyConfig*) _Py_GetConfig(void);
+
+
 /* cross-interpreter data */
 
 struct _xid;
diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 13a957a..c28df89 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -380,6 +380,10 @@ PyAPI_FUNC(void) _PyInterpreterState_DeleteExceptMain(_PyRuntimeState *runtime);
 /* Used by _PyImport_Cleanup() */
 extern void _PyInterpreterState_ClearModules(PyInterpreterState *interp);
 
+extern PyStatus _PyInterpreterState_SetConfig(
+    PyInterpreterState *interp,
+    const PyConfig *config);
+
 PyAPI_FUNC(void) _PyGILState_Reinit(_PyRuntimeState *runtime);
 
 
diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index e880992..571f225 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -9,7 +9,6 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
-#include "pycore_pystate.h"   /* _PyInterpreterState_GET_UNSAFE() */
 #include "structmember.h"
 #include "_iomodule.h"
 
@@ -377,7 +376,7 @@ _io_open_impl(PyObject *module, PyObject *file, const char *mode,
     {
         PyObject *RawIO_class = (PyObject *)&PyFileIO_Type;
 #ifdef MS_WINDOWS
-        PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
+        const PyConfig *config = _Py_GetConfig();
         if (!config->legacy_windows_stdio && _PyIO_get_console_type(path_or_fd) != '\0') {
             RawIO_class = (PyObject *)&PyWindowsConsoleIO_Type;
             encoding = "utf-8";
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index 1ff3564..924ffb5 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -287,8 +287,7 @@ iobase_finalize(PyObject *self)
            shutdown issues). */
         if (res == NULL) {
 #ifndef Py_DEBUG
-            const PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
-            if (config->dev_mode) {
+            if (_Py_GetConfig()->dev_mode) {
                 PyErr_WriteUnraisable(self);
             }
             else {
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 92d6faa..492988e 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -9,6 +9,7 @@
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 #include "pycore_object.h"
+#include "pycore_pystate.h"
 #include "structmember.h"
 #include "_iomodule.h"
 
@@ -996,7 +997,7 @@ io_check_errors(PyObject *errors)
     PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
 #ifndef Py_DEBUG
     /* In release mode, only check in development mode (-X dev) */
-    if (!interp->config.dev_mode) {
+    if (!_PyInterpreterState_GetConfig(interp)->dev_mode) {
         return 0;
     }
 #else
diff --git a/Modules/main.c b/Modules/main.c
index 0288f17..00a0fc3 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -301,7 +301,7 @@ pymain_run_module(const wchar_t *modname, int set_argv0)
 
 
 static int
-pymain_run_file(PyConfig *config, PyCompilerFlags *cf)
+pymain_run_file(const PyConfig *config, PyCompilerFlags *cf)
 {
     const wchar_t *filename = config->run_filename;
     if (PySys_Audit("cpython.run_file", "u", filename) < 0) {
@@ -499,7 +499,7 @@ pymain_run_python(int *exitcode)
 {
     PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
     /* pymain_run_stdin() modify the config */
-    PyConfig *config = &interp->config;
+    PyConfig *config = (PyConfig*)_PyInterpreterState_GetConfig(interp);
 
     PyObject *main_importer_path = NULL;
     if (config->run_filename != NULL) {
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 7ebfa1f..4d1ddec 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -6,7 +6,6 @@
 #include "pycore_bytes_methods.h"
 #include "pycore_object.h"
 #include "pycore_pymem.h"
-#include "pycore_pystate.h"
 #include "structmember.h"
 #include "bytesobject.h"
 #include "pystrhex.h"
@@ -997,8 +996,7 @@ bytearray_repr(PyByteArrayObject *self)
 static PyObject *
 bytearray_str(PyObject *op)
 {
-    PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
-    if (config->bytes_warning) {
+    if (_Py_GetConfig()->bytes_warning) {
         if (PyErr_WarnEx(PyExc_BytesWarning,
                          "str() on a bytearray instance", 1)) {
                 return NULL;
@@ -1023,8 +1021,7 @@ bytearray_richcompare(PyObject *self, PyObject *other, int op)
     if (rc < 0)
         return NULL;
     if (rc) {
-        PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
-        if (config->bytes_warning && (op == Py_EQ || op == Py_NE)) {
+        if (_Py_GetConfig()->bytes_warning && (op == Py_EQ || op == Py_NE)) {
             if (PyErr_WarnEx(PyExc_BytesWarning,
                             "Comparison between bytearray and string", 1))
                 return NULL;
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 7be075b..30bc739 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -7,7 +7,6 @@
 #include "pycore_bytes_methods.h"
 #include "pycore_object.h"
 #include "pycore_pymem.h"
-#include "pycore_pystate.h"
 
 #include "pystrhex.h"
 #include <stddef.h>
@@ -1342,8 +1341,7 @@ bytes_repr(PyObject *op)
 static PyObject *
 bytes_str(PyObject *op)
 {
-    PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
-    if (config->bytes_warning) {
+    if (_Py_GetConfig()->bytes_warning) {
         if (PyErr_WarnEx(PyExc_BytesWarning,
                          "str() on a bytes instance", 1)) {
             return NULL;
@@ -1500,8 +1498,7 @@ bytes_richcompare(PyBytesObject *a, PyBytesObject *b, int op)
 
     /* Make sure both arguments are strings. */
     if (!(PyBytes_Check(a) && PyBytes_Check(b))) {
-        PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
-        if (config->bytes_warning && (op == Py_EQ || op == Py_NE)) {
+        if (_Py_GetConfig()->bytes_warning && (op == Py_EQ || op == Py_NE)) {
             rc = PyObject_IsInstance((PyObject*)a,
                                      (PyObject*)&PyUnicode_Type);
             if (!rc)
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index f02ca75..30adc92 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -572,7 +572,7 @@ _PyModule_ClearDict(PyObject *d)
     Py_ssize_t pos;
     PyObject *key, *value;
 
-    int verbose = _PyInterpreterState_GET_UNSAFE()->config.verbose;
+    int verbose = _Py_GetConfig()->verbose;
 
     /* First, clear only names starting with a single underscore */
     pos = 0;
@@ -659,7 +659,7 @@ module___init___impl(PyModuleObject *self, PyObject *name, PyObject *doc)
 static void
 module_dealloc(PyModuleObject *m)
 {
-    int verbose = _PyInterpreterState_GET_UNSAFE()->config.verbose;
+    int verbose = _Py_GetConfig()->verbose;
 
     PyObject_GC_UnTrack(m);
     if (verbose && m->md_name) {
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 7f39022..938df24 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -439,7 +439,7 @@ unicode_check_encoding_errors(const char *encoding, const char *errors)
     PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
 #ifndef Py_DEBUG
     /* In release mode, only check in development mode (-X dev) */
-    if (!interp->config.dev_mode) {
+    if (!_PyInterpreterState_GetConfig(interp)->dev_mode) {
         return 0;
     }
 #else
@@ -3632,7 +3632,8 @@ PyUnicode_EncodeFSDefault(PyObject *unicode)
         /* Before _PyUnicode_InitEncodings() is called, the Python codec
            machinery is not ready and so cannot be used:
            use wcstombs() in this case. */
-        const wchar_t *filesystem_errors = interp->config.filesystem_errors;
+        const PyConfig *config = _PyInterpreterState_GetConfig(interp);
+        const wchar_t *filesystem_errors = config->filesystem_errors;
         assert(filesystem_errors != NULL);
         _Py_error_handler errors = get_error_handler_wide(filesystem_errors);
         assert(errors != _Py_ERROR_UNKNOWN);
@@ -3868,7 +3869,8 @@ PyUnicode_DecodeFSDefaultAndSize(const char *s, Py_ssize_t size)
         /* Before _PyUnicode_InitEncodings() is called, the Python codec
            machinery is not ready and so cannot be used:
            use mbstowcs() in this case. */
-        const wchar_t *filesystem_errors = interp->config.filesystem_errors;
+        const PyConfig *config = _PyInterpreterState_GetConfig(interp);
+        const wchar_t *filesystem_errors = config->filesystem_errors;
         assert(filesystem_errors != NULL);
         _Py_error_handler errors = get_error_handler_wide(filesystem_errors);
         assert(errors != _Py_ERROR_UNKNOWN);
@@ -15894,7 +15896,7 @@ static PyStatus
 init_stdio_encoding(PyThreadState *tstate)
 {
     /* Update the stdio encoding to the normalized Python codec name. */
-    PyConfig *config = &tstate->interp->config;
+    PyConfig *config = (PyConfig*)_PyInterpreterState_GetConfig(tstate->interp);
     if (config_get_codec_name(&config->stdio_encoding) < 0) {
         return _PyStatus_ERR("failed to get the Python codec name "
                              "of the stdio encoding");
@@ -15906,7 +15908,7 @@ init_stdio_encoding(PyThreadState *tstate)
 static int
 init_fs_codec(PyInterpreterState *interp)
 {
-    PyConfig *config = &interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(interp);
 
     _Py_error_handler error_handler;
     error_handler = get_error_handler_wide(config->filesystem_errors);
@@ -15964,7 +15966,7 @@ init_fs_encoding(PyThreadState *tstate)
     /* Update the filesystem encoding to the normalized Python codec name.
        For example, replace "ANSI_X3.4-1968" (locale encoding) with "ascii"
        (Python codec name). */
-    PyConfig *config = &interp->config;
+    PyConfig *config = (PyConfig*)_PyInterpreterState_GetConfig(interp);
     if (config_get_codec_name(&config->filesystem_encoding) < 0) {
         _Py_DumpPathConfig(tstate);
         return _PyStatus_ERR("failed to get the Python codec "
@@ -16008,7 +16010,7 @@ int
 _PyUnicode_EnableLegacyWindowsFSEncoding(void)
 {
     PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
-    PyConfig *config = &interp->config;
+    PyConfig *config = (PyConfig *)_PyInterpreterState_GetConfig(interp);
 
     /* Set the filesystem encoding to mbcs/replace (PEP 529) */
     wchar_t *encoding = _PyMem_RawWcsdup(L"mbcs");
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index cb048af..8063c21 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2770,7 +2770,7 @@ _PyBuiltin_Init(PyThreadState *tstate)
 {
     PyObject *mod, *dict, *debug;
 
-    const PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
 
     if (PyType_Ready(&PyFilter_Type) < 0 ||
         PyType_Ready(&PyMap_Type) < 0 ||
diff --git a/Python/compile.c b/Python/compile.c
index 329add9..54e6516 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -23,7 +23,6 @@
 
 #include "Python.h"
 
-#include "pycore_pystate.h"   /* _PyInterpreterState_GET_UNSAFE() */
 #include "Python-ast.h"
 #include "ast.h"
 #include "code.h"
@@ -323,7 +322,6 @@ PyAST_CompileObject(mod_ty mod, PyObject *filename, PyCompilerFlags *flags,
     PyCodeObject *co = NULL;
     PyCompilerFlags local_flags = _PyCompilerFlags_INIT;
     int merged;
-    PyConfig *config = &_PyInterpreterState_GET_UNSAFE()->config;
 
     if (!__doc__) {
         __doc__ = PyUnicode_InternFromString("__doc__");
@@ -350,7 +348,7 @@ PyAST_CompileObject(mod_ty mod, PyObject *filename, PyCompilerFlags *flags,
     c.c_future->ff_features = merged;
     flags->cf_flags = merged;
     c.c_flags = flags;
-    c.c_optimize = (optimize == -1) ? config->optimization_level : optimize;
+    c.c_optimize = (optimize == -1) ? _Py_GetConfig()->optimization_level : optimize;
     c.c_nestlevel = 0;
     c.c_do_not_emit_bytecode = 0;
 
diff --git a/Python/dynload_hpux.c b/Python/dynload_hpux.c
index e59d004..4b964a6 100644
--- a/Python/dynload_hpux.c
+++ b/Python/dynload_hpux.c
@@ -6,7 +6,6 @@
 
 #include "Python.h"
 #include "importdl.h"
-#include "pycore_pystate.h"
 
 #if defined(__hp9000s300)
 #define FUNCNAME_PATTERN "_%.20s_%.200s"
@@ -21,7 +20,7 @@ dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
                                        const char *pathname, FILE *fp)
 {
     int flags = BIND_FIRST | BIND_DEFERRED;
-    int verbose = _PyInterpreterState_GET_UNSAFE()->config.verbose;
+    int verbose = _Py_GetConfig()->verbose;
     if (verbose) {
         flags = BIND_FIRST | BIND_IMMEDIATE |
             BIND_NONFATAL | BIND_VERBOSE;
diff --git a/Python/import.c b/Python/import.c
index 2e43456..d79fa18 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -102,7 +102,7 @@ _PyImportZip_Init(PyThreadState *tstate)
         goto error;
     }
 
-    int verbose = tstate->interp->config.verbose;
+    int verbose = _PyInterpreterState_GetConfig(tstate->interp)->verbose;
     if (verbose) {
         PySys_WriteStderr("# installing zipimport hook\n");
     }
@@ -446,7 +446,7 @@ _PyImport_Cleanup(PyThreadState *tstate)
 
     /* XXX Perhaps these precautions are obsolete. Who knows? */
 
-    int verbose = interp->config.verbose;
+    int verbose = _PyInterpreterState_GetConfig(interp)->verbose;
     if (verbose) {
         PySys_WriteStderr("# clear builtins._\n");
     }
@@ -811,7 +811,7 @@ import_find_extension(PyThreadState *tstate, PyObject *name,
         return NULL;
     }
 
-    int verbose = tstate->interp->config.verbose;
+    int verbose = _PyInterpreterState_GetConfig(tstate->interp)->verbose;
     if (verbose) {
         PySys_FormatStderr("import %U # previously loaded (%R)\n",
                            name, filename);
@@ -1523,7 +1523,7 @@ remove_importlib_frames(PyThreadState *tstate)
        which end with a call to "_call_with_frames_removed". */
 
     _PyErr_Fetch(tstate, &exception, &value, &base_tb);
-    if (!exception || tstate->interp->config.verbose) {
+    if (!exception || _PyInterpreterState_GetConfig(tstate->interp)->verbose) {
         goto done;
     }
 
@@ -1727,7 +1727,7 @@ import_find_and_load(PyThreadState *tstate, PyObject *abs_name)
     _Py_IDENTIFIER(_find_and_load);
     PyObject *mod = NULL;
     PyInterpreterState *interp = tstate->interp;
-    int import_time = interp->config.import_time;
+    int import_time = _PyInterpreterState_GetConfig(interp)->import_time;
     static int import_level;
     static _PyTime_t accumulated;
 
@@ -2413,7 +2413,7 @@ PyInit__imp(void)
         goto failure;
     }
 
-    const wchar_t *mode = _PyInterpreterState_GET_UNSAFE()->config.check_hash_pycs_mode;
+    const wchar_t *mode = _Py_GetConfig()->check_hash_pycs_mode;
     PyObject *pyc_mode = PyUnicode_FromWideChar(mode, -1);
     if (pyc_mode == NULL) {
         goto failure;
diff --git a/Python/initconfig.c b/Python/initconfig.c
index 7bad36e..e63d6f6 100644
--- a/Python/initconfig.c
+++ b/Python/initconfig.c
@@ -2595,7 +2595,7 @@ _Py_GetConfigsAsDict(void)
     Py_CLEAR(dict);
 
     /* core config */
-    const PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
     dict = config_as_dict(config);
     if (dict == NULL) {
         goto error;
@@ -2662,7 +2662,7 @@ _Py_DumpPathConfig(PyThreadState *tstate)
             PySys_WriteStderr("\n"); \
         } while (0)
 
-    PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
     DUMP_CONFIG("PYTHONHOME", home);
     DUMP_CONFIG("PYTHONPATH", pythonpath_env);
     DUMP_CONFIG("program name", program_name);
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 9b413c6..1bc7d77 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -157,7 +157,7 @@ init_importlib(PyThreadState *tstate, PyObject *sysmod)
     PyObject *impmod;
     PyObject *value;
     PyInterpreterState *interp = tstate->interp;
-    int verbose = interp->config.verbose;
+    int verbose = _PyInterpreterState_GetConfig(interp)->verbose;
 
     /* Import _importlib through its frozen version, _frozen_importlib. */
     if (PyImport_ImportFrozenModule("_frozen_importlib") <= 0) {
@@ -473,11 +473,11 @@ pyinit_core_reconfigure(_PyRuntimeState *runtime,
 
     _PyConfig_Write(config, runtime);
 
-    status = _PyConfig_Copy(&interp->config, config);
+    status = _PyInterpreterState_SetConfig(interp, config);
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
-    config = &interp->config;
+    config = _PyInterpreterState_GetConfig(interp);
 
     if (config->_install_importlib) {
         status = _PyConfig_WritePathConfig(config);
@@ -558,7 +558,7 @@ pycore_create_interpreter(_PyRuntimeState *runtime,
         return _PyStatus_ERR("can't make main interpreter");
     }
 
-    PyStatus status = _PyConfig_Copy(&interp->config, config);
+    PyStatus status = _PyInterpreterState_SetConfig(interp, config);
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
@@ -692,7 +692,7 @@ pycore_init_import_warnings(PyThreadState *tstate, PyObject *sysmod)
         return status;
     }
 
-    const PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
     if (_Py_IsMainInterpreter(tstate)) {
         /* Initialize _warnings. */
         status = _PyWarnings_InitState(tstate);
@@ -953,7 +953,7 @@ done:
 static PyStatus
 _Py_ReconfigureMainInterpreter(PyThreadState *tstate)
 {
-    PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
 
     PyObject *argv = _PyWideStringList_AsList(&config->argv);
     if (argv == NULL) {
@@ -977,7 +977,7 @@ init_interp_main(PyThreadState *tstate)
     PyStatus status;
     int is_main_interp = _Py_IsMainInterpreter(tstate);
     PyInterpreterState *interp = tstate->interp;
-    PyConfig *config = &interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(interp);
 
     if (!config->_install_importlib) {
         /* Special mode for freeze_importlib: run with no import system
@@ -1146,7 +1146,7 @@ Py_InitializeFromConfig(const PyConfig *config)
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
-    config = &tstate->interp->config;
+    config = _PyInterpreterState_GetConfig(tstate->interp);
 
     if (config->_init_main) {
         status = pyinit_main(tstate);
@@ -1571,16 +1571,16 @@ new_interpreter(PyThreadState **tstate_p)
     PyThreadState *save_tstate = PyThreadState_Swap(tstate);
 
     /* Copy the current interpreter config into the new interpreter */
-    PyConfig *config;
+    const PyConfig *config;
     if (save_tstate != NULL) {
-        config = &save_tstate->interp->config;
+        config = _PyInterpreterState_GetConfig(save_tstate->interp);
     } else {
         /* No current thread state, copy from the main interpreter */
         PyInterpreterState *main_interp = PyInterpreterState_Main();
-        config = &main_interp->config;
+        config = _PyInterpreterState_GetConfig(main_interp);
     }
 
-    status = _PyConfig_Copy(&interp->config, config);
+    status = _PyInterpreterState_SetConfig(interp, config);
     if (_PyStatus_EXCEPTION(status)) {
         goto error;
     }
@@ -1953,7 +1953,7 @@ init_sys_streams(PyThreadState *tstate)
     int fd;
     PyObject * encoding_attr;
     PyStatus res = _PyStatus_OK();
-    const PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
 
     /* Check that stdin is not a directory
        Using shell redirection, you can redirect stdin to a directory,
diff --git a/Python/pystate.c b/Python/pystate.c
index 0539096..19beaf0 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -790,7 +790,7 @@ _PyInterpreterState_ClearModules(PyInterpreterState *interp)
 void
 PyThreadState_Clear(PyThreadState *tstate)
 {
-    int verbose = tstate->interp->config.verbose;
+    int verbose = _PyInterpreterState_GetConfig(tstate->interp)->verbose;
 
     if (verbose && tstate->frame != NULL) {
         /* bpo-20526: After the main thread calls
@@ -1808,6 +1808,30 @@ _PyInterpreterState_SetEvalFrameFunc(PyInterpreterState *interp,
     interp->eval_frame = eval_frame;
 }
 
+
+const PyConfig*
+_PyInterpreterState_GetConfig(PyInterpreterState *interp)
+{
+    return &interp->config;
+}
+
+
+PyStatus
+_PyInterpreterState_SetConfig(PyInterpreterState *interp,
+                              const PyConfig *config)
+{
+    return _PyConfig_Copy(&interp->config, config);
+}
+
+
+const PyConfig*
+_Py_GetConfig(void)
+{
+    assert(PyGILState_Check());
+    PyThreadState *tstate = _PyThreadState_GET();
+    return _PyInterpreterState_GetConfig(tstate->interp);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index eb9159f..522d152 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -96,7 +96,7 @@ PyRun_InteractiveLoopFlags(FILE *fp, const char *filename_str, PyCompilerFlags *
     PyCompilerFlags local_flags = _PyCompilerFlags_INIT;
     int nomem_count = 0;
 #ifdef Py_REF_DEBUG
-    int show_ref_count = _PyInterpreterState_GET_UNSAFE()->config.show_ref_count;
+    int show_ref_count = _Py_GetConfig()->show_ref_count;
 #endif
 
     filename = PyUnicode_DecodeFSDefault(filename_str);
@@ -584,7 +584,7 @@ print_error_text(PyObject *f, int offset, PyObject *text_obj)
 int
 _Py_HandleSystemExit(int *exitcode_p)
 {
-    int inspect = _PyInterpreterState_GET_UNSAFE()->config.inspect;
+    int inspect = _Py_GetConfig()->inspect;
     if (inspect) {
         /* Don't exit if -i flag was given. This flag is set to 0
          * when entering interactive mode for inspecting. */
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 994e358..fd0a9c0 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -23,7 +23,6 @@ Data members:
 #include "pycore_pyerrors.h"
 #include "pycore_pylifecycle.h"
 #include "pycore_pymem.h"
-#include "pycore_pystate.h"
 #include "pycore_tupleobject.h"
 #include "pythread.h"
 #include "pydtrace.h"
@@ -337,7 +336,7 @@ _PySys_ClearAuditHooks(PyThreadState *ts)
         return;
     }
 
-    const PyConfig *config = &ts->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(ts->interp);
     if (config->verbose) {
         PySys_WriteStderr("# clear sys.audit hooks\n");
     }
@@ -846,8 +845,8 @@ static PyObject *
 sys_getfilesystemencoding_impl(PyObject *module)
 /*[clinic end generated code: output=1dc4bdbe9be44aa7 input=8475f8649b8c7d8c]*/
 {
-    PyThreadState *tstate = _PyThreadState_GET();
-    const PyConfig *config = &tstate->interp->config;
+    PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
+    const PyConfig *config = _PyInterpreterState_GetConfig(interp);
     return PyUnicode_FromWideChar(config->filesystem_encoding, -1);
 }
 
@@ -861,8 +860,8 @@ static PyObject *
 sys_getfilesystemencodeerrors_impl(PyObject *module)
 /*[clinic end generated code: output=ba77b36bbf7c96f5 input=22a1e8365566f1e5]*/
 {
-    PyThreadState *tstate = _PyThreadState_GET();
-    const PyConfig *config = &tstate->interp->config;
+    PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
+    const PyConfig *config = _PyInterpreterState_GetConfig(interp);
     return PyUnicode_FromWideChar(config->filesystem_errors, -1);
 }
 
@@ -2455,7 +2454,7 @@ make_flags(PyThreadState *tstate)
 {
     PyInterpreterState *interp = tstate->interp;
     const PyPreConfig *preconfig = &interp->runtime->preconfig;
-    const PyConfig *config = &interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(interp);
 
     PyObject *seq = PyStructSequence_New(&FlagsType);
     if (seq == NULL) {
@@ -2889,7 +2888,7 @@ int
 _PySys_InitMain(PyThreadState *tstate)
 {
     PyObject *sysdict = tstate->interp->sysdict;
-    const PyConfig *config = &tstate->interp->config;
+    const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
     int res;
 
 #define COPY_LIST(KEY, VALUE) \