Python/initconfig.c

#include "Python.h"
#include "osdefs.h"       /* DELIM */
#include "pycore_fileutils.h"
#include "pycore_getopt.h"
#include "pycore_initconfig.h"
#include "pycore_pathconfig.h"
#include "pycore_pyerrors.h"
#include "pycore_pylifecycle.h"
#include "pycore_pymem.h"
#include "pycore_pystate.h"   /* _PyRuntime */
#include <locale.h>       /* setlocale() */
#ifdef HAVE_LANGINFO_H
#  include <langinfo.h>   /* nl_langinfo(CODESET) */
#endif
#if defined(MS_WINDOWS) || defined(__CYGWIN__)
#  include <windows.h>    /* GetACP() */
#  ifdef HAVE_IO_H
#    include <io.h>
#  endif
#  ifdef HAVE_FCNTL_H
#    include <fcntl.h>    /* O_BINARY */
#  endif
#endif


/* --- Command line options --------------------------------------- */

/* Short usage message (with %s for argv0) */
static const char usage_line[] =
"usage: %ls [option] ... [-c cmd | -m mod | file | -] [arg] ...\n";

/* Long usage message, split into parts < 512 bytes */
static const char usage_1[] = "\
Options and arguments (and corresponding environment variables):\n\
-b     : issue warnings about str(bytes_instance), str(bytearray_instance)\n\
         and comparing bytes/bytearray with str. (-bb: issue errors)\n\
-B     : don't write .pyc files on import; also PYTHONDONTWRITEBYTECODE=x\n\
-c cmd : program passed in as string (terminates option list)\n\
-d     : debug output from parser; also PYTHONDEBUG=x\n\
-E     : ignore PYTHON* environment variables (such as PYTHONPATH)\n\
-h     : print this help message and exit (also --help)\n\
";
static const char usage_2[] = "\
-i     : inspect interactively after running script; forces a prompt even\n\
         if stdin does not appear to be a terminal; also PYTHONINSPECT=x\n\
-I     : isolate Python from the user's environment (implies -E and -s)\n\
-m mod : run library module as a script (terminates option list)\n\
-O     : remove assert and __debug__-dependent statements; add .opt-1 before\n\
         .pyc extension; also PYTHONOPTIMIZE=x\n\
-OO    : do -O changes and also discard docstrings; add .opt-2 before\n\
         .pyc extension\n\
-q     : don't print version and copyright messages on interactive startup\n\
-s     : don't add user site directory to sys.path; also PYTHONNOUSERSITE\n\
-S     : don't imply 'import site' on initialization\n\
";
static const char usage_3[] = "\
-u     : force the stdout and stderr streams to be unbuffered;\n\
         this option has no effect on stdin; also PYTHONUNBUFFERED=x\n\
-v     : verbose (trace import statements); also PYTHONVERBOSE=x\n\
         can be supplied multiple times to increase verbosity\n\
-V     : print the Python version number and exit (also --version)\n\
         when given twice, print more information about the build\n\
-W arg : warning control; arg is action:message:category:module:lineno\n\
         also PYTHONWARNINGS=arg\n\
-x     : skip first line of source, allowing use of non-Unix forms of #!cmd\n\
-X opt : set implementation-specific option. The following options are available:\n\
\n\
         -X faulthandler: enable faulthandler\n\
         -X showrefcount: output the total reference count and number of used\n\
             memory blocks when the program finishes or after each statement in the\n\
             interactive interpreter. This only works on debug builds\n\
         -X tracemalloc: start tracing Python memory allocations using the\n\
             tracemalloc module. By default, only the most recent frame is stored in a\n\
             traceback of a trace. Use -X tracemalloc=NFRAME to start tracing with a\n\
             traceback limit of NFRAME frames\n\
         -X showalloccount: output the total count of allocated objects for each\n\
             type when the program finishes. This only works when Python was built with\n\
             COUNT_ALLOCS defined\n\
         -X importtime: show how long each import takes. It shows module name,\n\
             cumulative time (including nested imports) and self time (excluding\n\
             nested imports). Note that its output may be broken in multi-threaded\n\
             application. Typical usage is python3 -X importtime -c 'import asyncio'\n\
         -X dev: enable CPython’s “development mode”, introducing additional runtime\n\
             checks which are too expensive to be enabled by default. Effect of the\n\
             developer mode:\n\
                * Add default warning filter, as -W default\n\
                * Install debug hooks on memory allocators: see the PyMem_SetupDebugHooks() C function\n\
                * Enable the faulthandler module to dump the Python traceback on a crash\n\
                * Enable asyncio debug mode\n\
                * Set the dev_mode attribute of sys.flags to True\n\
                * io.IOBase destructor logs close() exceptions\n\
         -X utf8: enable UTF-8 mode for operating system interfaces, overriding the default\n\
             locale-aware mode. -X utf8=0 explicitly disables UTF-8 mode (even when it would\n\
             otherwise activate automatically)\n\
         -X pycache_prefix=PATH: enable writing .pyc files to a parallel tree rooted at the\n\
             given directory instead of to the code tree\n\
\n\
--check-hash-based-pycs always|default|never:\n\
    control how Python invalidates hash-based .pyc files\n\
";
static const char usage_4[] = "\
file   : program read from script file\n\
-      : program read from stdin (default; interactive mode if a tty)\n\
arg ...: arguments passed to program in sys.argv[1:]\n\n\
Other environment variables:\n\
PYTHONSTARTUP: file executed on interactive startup (no default)\n\
PYTHONPATH   : '%lc'-separated list of directories prefixed to the\n\
               default module search path.  The result is sys.path.\n\
";
static const char usage_5[] =
"PYTHONHOME   : alternate <prefix> directory (or <prefix>%lc<exec_prefix>).\n"
"               The default module search path uses %s.\n"
"PYTHONCASEOK : ignore case in 'import' statements (Windows).\n"
"PYTHONUTF8: if set to 1, enable the UTF-8 mode.\n"
"PYTHONIOENCODING: Encoding[:errors] used for stdin/stdout/stderr.\n"
"PYTHONFAULTHANDLER: dump the Python traceback on fatal errors.\n";
static const char usage_6[] =
"PYTHONHASHSEED: if this variable is set to 'random', a random value is used\n"
"   to seed the hashes of str and bytes objects.  It can also be set to an\n"
"   integer in the range [0,4294967295] to get hash values with a\n"
"   predictable seed.\n"
"PYTHONMALLOC: set the Python memory allocators and/or install debug hooks\n"
"   on Python memory allocators. Use PYTHONMALLOC=debug to install debug\n"
"   hooks.\n"
"PYTHONCOERCECLOCALE: if this variable is set to 0, it disables the locale\n"
"   coercion behavior. Use PYTHONCOERCECLOCALE=warn to request display of\n"
"   locale coercion and locale compatibility warnings on stderr.\n"
"PYTHONBREAKPOINT: if this variable is set to 0, it disables the default\n"
"   debugger. It can be set to the callable of your debugger of choice.\n"
"PYTHONDEVMODE: enable the development mode.\n"
"PYTHONPYCACHEPREFIX: root directory for bytecode cache (pyc) files.\n";

#if defined(MS_WINDOWS)
#  define PYTHONHOMEHELP "<prefix>\\python{major}{minor}"
#else
#  define PYTHONHOMEHELP "<prefix>/lib/pythonX.X"
#endif


/* --- Global configuration variables ----------------------------- */

/* UTF-8 mode (PEP 540): if equals to 1, use the UTF-8 encoding, and change
   stdin and stdout error handler to "surrogateescape". */
int Py_UTF8Mode = 0;
int Py_DebugFlag = 0; /* Needed by parser.c */
int Py_VerboseFlag = 0; /* Needed by import.c */
int Py_QuietFlag = 0; /* Needed by sysmodule.c */
int Py_InteractiveFlag = 0; /* Needed by Py_FdIsInteractive() below */
int Py_InspectFlag = 0; /* Needed to determine whether to exit at SystemExit */
int Py_OptimizeFlag = 0; /* Needed by compile.c */
int Py_NoSiteFlag = 0; /* Suppress 'import site' */
int Py_BytesWarningFlag = 0; /* Warn on str(bytes) and str(buffer) */
int Py_FrozenFlag = 0; /* Needed by getpath.c */
int Py_IgnoreEnvironmentFlag = 0; /* e.g. PYTHONPATH, PYTHONHOME */
int Py_DontWriteBytecodeFlag = 0; /* Suppress writing bytecode files (*.pyc) */
int Py_NoUserSiteDirectory = 0; /* for -s and site.py */
int Py_UnbufferedStdioFlag = 0; /* Unbuffered binary std{in,out,err} */
int Py_HashRandomizationFlag = 0; /* for -R and PYTHONHASHSEED */
int Py_IsolatedFlag = 0; /* for -I, isolate from user's env */
#ifdef MS_WINDOWS
int Py_LegacyWindowsFSEncodingFlag = 0; /* Uses mbcs instead of utf-8 */
int Py_LegacyWindowsStdioFlag = 0; /* Uses FileIO instead of WindowsConsoleIO */
#endif


static PyObject *
_Py_GetGlobalVariablesAsDict(void)
{
    PyObject *dict, *obj;

    dict = PyDict_New();
    if (dict == NULL) {
        return NULL;
    }

#define SET_ITEM(KEY, EXPR) \
        do { \
            obj = (EXPR); \
            if (obj == NULL) { \
                return NULL; \
            } \
            int res = PyDict_SetItemString(dict, (KEY), obj); \
            Py_DECREF(obj); \
            if (res < 0) { \
                goto fail; \
            } \
        } while (0)
#define SET_ITEM_INT(VAR) \
    SET_ITEM(#VAR, PyLong_FromLong(VAR))
#define FROM_STRING(STR) \
    ((STR != NULL) ? \
        PyUnicode_FromString(STR) \
        : (Py_INCREF(Py_None), Py_None))
#define SET_ITEM_STR(VAR) \
    SET_ITEM(#VAR, FROM_STRING(VAR))

    SET_ITEM_STR(Py_FileSystemDefaultEncoding);
    SET_ITEM_INT(Py_HasFileSystemDefaultEncoding);
    SET_ITEM_STR(Py_FileSystemDefaultEncodeErrors);
    SET_ITEM_INT(_Py_HasFileSystemDefaultEncodeErrors);

    SET_ITEM_INT(Py_UTF8Mode);
    SET_ITEM_INT(Py_DebugFlag);
    SET_ITEM_INT(Py_VerboseFlag);
    SET_ITEM_INT(Py_QuietFlag);
    SET_ITEM_INT(Py_InteractiveFlag);
    SET_ITEM_INT(Py_InspectFlag);

    SET_ITEM_INT(Py_OptimizeFlag);
    SET_ITEM_INT(Py_NoSiteFlag);
    SET_ITEM_INT(Py_BytesWarningFlag);
    SET_ITEM_INT(Py_FrozenFlag);
    SET_ITEM_INT(Py_IgnoreEnvironmentFlag);
    SET_ITEM_INT(Py_DontWriteBytecodeFlag);
    SET_ITEM_INT(Py_NoUserSiteDirectory);
    SET_ITEM_INT(Py_UnbufferedStdioFlag);
    SET_ITEM_INT(Py_HashRandomizationFlag);
    SET_ITEM_INT(Py_IsolatedFlag);

#ifdef MS_WINDOWS
    SET_ITEM_INT(Py_LegacyWindowsFSEncodingFlag);
    SET_ITEM_INT(Py_LegacyWindowsStdioFlag);
#endif

    return dict;

fail:
    Py_DECREF(dict);
    return NULL;

#undef FROM_STRING
#undef SET_ITEM
#undef SET_ITEM_INT
#undef SET_ITEM_STR
}


/* --- PyStatus ----------------------------------------------- */

PyStatus PyStatus_Ok(void)
{ return _PyStatus_OK(); }

PyStatus PyStatus_Error(const char *err_msg)
{
    return (PyStatus){._type = _PyStatus_TYPE_ERROR,
                          .err_msg = err_msg};
}

PyStatus PyStatus_NoMemory(void)
{ return PyStatus_Error("memory allocation failed"); }

PyStatus PyStatus_Exit(int exitcode)
{ return _PyStatus_EXIT(exitcode); }


int PyStatus_IsError(PyStatus status)
{ return _PyStatus_IS_ERROR(status); }

int PyStatus_IsExit(PyStatus status)
{ return _PyStatus_IS_EXIT(status); }

int PyStatus_Exception(PyStatus status)
{ return _PyStatus_EXCEPTION(status); }


/* --- PyWideStringList ------------------------------------------------ */

#ifndef NDEBUG
int
_PyWideStringList_CheckConsistency(const PyWideStringList *list)
{
    assert(list->length >= 0);
    if (list->length != 0) {
        assert(list->items != NULL);
    }
    for (Py_ssize_t i = 0; i < list->length; i++) {
        assert(list->items[i] != NULL);
    }
    return 1;
}
#endif   /* Py_DEBUG */


void
_PyWideStringList_Clear(PyWideStringList *list)
{
    assert(_PyWideStringList_CheckConsistency(list));
    for (Py_ssize_t i=0; i < list->length; i++) {
        PyMem_RawFree(list->items[i]);
    }
    PyMem_RawFree(list->items);
    list->length = 0;
    list->items = NULL;
}


int
_PyWideStringList_Copy(PyWideStringList *list, const PyWideStringList *list2)
{
    assert(_PyWideStringList_CheckConsistency(list));
    assert(_PyWideStringList_CheckConsistency(list2));

    if (list2->length == 0) {
        _PyWideStringList_Clear(list);
        return 0;
    }

    PyWideStringList copy = _PyWideStringList_INIT;

    size_t size = list2->length * sizeof(list2->items[0]);
    copy.items = PyMem_RawMalloc(size);
    if (copy.items == NULL) {
        return -1;
    }

    for (Py_ssize_t i=0; i < list2->length; i++) {
        wchar_t *item = _PyMem_RawWcsdup(list2->items[i]);
        if (item == NULL) {
            _PyWideStringList_Clear(&copy);
            return -1;
        }
        copy.items[i] = item;
        copy.length = i + 1;
    }

    _PyWideStringList_Clear(list);
    *list = copy;
    return 0;
}


PyStatus
PyWideStringList_Insert(PyWideStringList *list,
                        Py_ssize_t index, const wchar_t *item)
{
    Py_ssize_t len = list->length;
    if (len == PY_SSIZE_T_MAX) {
        /* length+1 would overflow */
        return _PyStatus_NO_MEMORY();
    }
    if (index < 0) {
        return _PyStatus_ERR("PyWideStringList_Insert index must be >= 0");
    }
    if (index > len) {
        index = len;
    }

    wchar_t *item2 = _PyMem_RawWcsdup(item);
    if (item2 == NULL) {
        return _PyStatus_NO_MEMORY();
    }

    size_t size = (len + 1) * sizeof(list->items[0]);
    wchar_t **items2 = (wchar_t **)PyMem_RawRealloc(list->items, size);
    if (items2 == NULL) {
        PyMem_RawFree(item2);
        return _PyStatus_NO_MEMORY();
    }

    if (index < len) {
        memmove(&items2[index + 1],
                &items2[index],
                (len - index) * sizeof(items2[0]));
    }

    items2[index] = item2;
    list->items = items2;
    list->length++;
    return _PyStatus_OK();
}


PyStatus
PyWideStringList_Append(PyWideStringList *list, const wchar_t *item)
{
    return PyWideStringList_Insert(list, list->length, item);
}


PyStatus
_PyWideStringList_Extend(PyWideStringList *list, const PyWideStringList *list2)
{
    for (Py_ssize_t i = 0; i < list2->length; i++) {
        PyStatus status = PyWideStringList_Append(list, list2->items[i]);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }
    return _PyStatus_OK();
}


static int
_PyWideStringList_Find(PyWideStringList *list, const wchar_t *item)
{
    for (Py_ssize_t i = 0; i < list->length; i++) {
        if (wcscmp(list->items[i], item) == 0) {
            return 1;
        }
    }
    return 0;
}


PyObject*
_PyWideStringList_AsList(const PyWideStringList *list)
{
    assert(_PyWideStringList_CheckConsistency(list));

    PyObject *pylist = PyList_New(list->length);
    if (pylist == NULL) {
        return NULL;
    }

    for (Py_ssize_t i = 0; i < list->length; i++) {
        PyObject *item = PyUnicode_FromWideChar(list->items[i], -1);
        if (item == NULL) {
            Py_DECREF(pylist);
            return NULL;
        }
        PyList_SET_ITEM(pylist, i, item);
    }
    return pylist;
}


/* --- Py_SetStandardStreamEncoding() ----------------------------- */

/* Helper to allow an embedding application to override the normal
 * mechanism that attempts to figure out an appropriate IO encoding
 */

static char *_Py_StandardStreamEncoding = NULL;
static char *_Py_StandardStreamErrors = NULL;

int
Py_SetStandardStreamEncoding(const char *encoding, const char *errors)
{
    if (Py_IsInitialized()) {
        /* This is too late to have any effect */
        return -1;
    }

    int res = 0;

    /* Py_SetStandardStreamEncoding() can be called before Py_Initialize(),
       but Py_Initialize() can change the allocator. Use a known allocator
       to be able to release the memory later. */
    PyMemAllocatorEx old_alloc;
    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);

    /* Can't call PyErr_NoMemory() on errors, as Python hasn't been
     * initialised yet.
     *
     * However, the raw memory allocators are initialised appropriately
     * as C static variables, so _PyMem_RawStrdup is OK even though
     * Py_Initialize hasn't been called yet.
     */
    if (encoding) {
        PyMem_RawFree(_Py_StandardStreamEncoding);
        _Py_StandardStreamEncoding = _PyMem_RawStrdup(encoding);
        if (!_Py_StandardStreamEncoding) {
            res = -2;
            goto done;
        }
    }
    if (errors) {
        PyMem_RawFree(_Py_StandardStreamErrors);
        _Py_StandardStreamErrors = _PyMem_RawStrdup(errors);
        if (!_Py_StandardStreamErrors) {
            PyMem_RawFree(_Py_StandardStreamEncoding);
            _Py_StandardStreamEncoding = NULL;
            res = -3;
            goto done;
        }
    }
#ifdef MS_WINDOWS
    if (_Py_StandardStreamEncoding) {
        /* Overriding the stream encoding implies legacy streams */
        Py_LegacyWindowsStdioFlag = 1;
    }
#endif

done:
    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);

    return res;
}


void
_Py_ClearStandardStreamEncoding(void)
{
    /* Use the same allocator than Py_SetStandardStreamEncoding() */
    PyMemAllocatorEx old_alloc;
    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);

    /* We won't need them anymore. */
    if (_Py_StandardStreamEncoding) {
        PyMem_RawFree(_Py_StandardStreamEncoding);
        _Py_StandardStreamEncoding = NULL;
    }
    if (_Py_StandardStreamErrors) {
        PyMem_RawFree(_Py_StandardStreamErrors);
        _Py_StandardStreamErrors = NULL;
    }

    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
}


/* --- Py_GetArgcArgv() ------------------------------------------- */

/* For Py_GetArgcArgv(); set by _Py_SetArgcArgv() */
static PyWideStringList orig_argv = {.length = 0, .items = NULL};


void
_Py_ClearArgcArgv(void)
{
    PyMemAllocatorEx old_alloc;
    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);

    _PyWideStringList_Clear(&orig_argv);

    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
}


static int
_Py_SetArgcArgv(Py_ssize_t argc, wchar_t * const *argv)
{
    const PyWideStringList argv_list = {.length = argc, .items = (wchar_t **)argv};
    int res;

    PyMemAllocatorEx old_alloc;
    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);

    res = _PyWideStringList_Copy(&orig_argv, &argv_list);

    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
    return res;
}


/* Make the *original* argc/argv available to other modules.
   This is rare, but it is needed by the secureware extension. */
void
Py_GetArgcArgv(int *argc, wchar_t ***argv)
{
    *argc = (int)orig_argv.length;
    *argv = orig_argv.items;
}


/* --- PyConfig ---------------------------------------------- */

#define DECODE_LOCALE_ERR(NAME, LEN) \
    (((LEN) == -2) \
     ? _PyStatus_ERR("cannot decode " NAME) \
     : _PyStatus_NO_MEMORY())


/* Free memory allocated in config, but don't clear all attributes */
void
PyConfig_Clear(PyConfig *config)
{
#define CLEAR(ATTR) \
    do { \
        PyMem_RawFree(ATTR); \
        ATTR = NULL; \
    } while (0)

    CLEAR(config->pycache_prefix);
    CLEAR(config->pythonpath_env);
    CLEAR(config->home);
    CLEAR(config->program_name);

    _PyWideStringList_Clear(&config->argv);
    _PyWideStringList_Clear(&config->warnoptions);
    _PyWideStringList_Clear(&config->xoptions);
    _PyWideStringList_Clear(&config->module_search_paths);
    config->module_search_paths_set = 0;

    CLEAR(config->executable);
    CLEAR(config->base_executable);
    CLEAR(config->prefix);
    CLEAR(config->base_prefix);
    CLEAR(config->exec_prefix);
    CLEAR(config->base_exec_prefix);

    CLEAR(config->filesystem_encoding);
    CLEAR(config->filesystem_errors);
    CLEAR(config->stdio_encoding);
    CLEAR(config->stdio_errors);
    CLEAR(config->run_command);
    CLEAR(config->run_module);
    CLEAR(config->run_filename);
    CLEAR(config->check_hash_pycs_mode);
#undef CLEAR
}


void
_PyConfig_InitCompatConfig(PyConfig *config)
{
    memset(config, 0, sizeof(*config));

    config->_config_init = (int)_PyConfig_INIT_COMPAT;
    config->isolated = -1;
    config->use_environment = -1;
    config->dev_mode = -1;
    config->install_signal_handlers = 1;
    config->use_hash_seed = -1;
    config->faulthandler = -1;
    config->tracemalloc = -1;
    config->module_search_paths_set = 0;
    config->parse_argv = 0;
    config->site_import = -1;
    config->bytes_warning = -1;
    config->inspect = -1;
    config->interactive = -1;
    config->optimization_level = -1;
    config->parser_debug= -1;
    config->write_bytecode = -1;
    config->verbose = -1;
    config->quiet = -1;
    config->user_site_directory = -1;
    config->configure_c_stdio = 0;
    config->buffered_stdio = -1;
    config->_install_importlib = 1;
    config->check_hash_pycs_mode = NULL;
    config->pathconfig_warnings = -1;
    config->_init_main = 1;
#ifdef MS_WINDOWS
    config->legacy_windows_stdio = -1;
#endif
}


static void
config_init_defaults(PyConfig *config)
{
    _PyConfig_InitCompatConfig(config);

    config->isolated = 0;
    config->use_environment = 1;
    config->site_import = 1;
    config->bytes_warning = 0;
    config->inspect = 0;
    config->interactive = 0;
    config->optimization_level = 0;
    config->parser_debug= 0;
    config->write_bytecode = 1;
    config->verbose = 0;
    config->quiet = 0;
    config->user_site_directory = 1;
    config->buffered_stdio = 1;
    config->pathconfig_warnings = 1;
#ifdef MS_WINDOWS
    config->legacy_windows_stdio = 0;
#endif
}


void
PyConfig_InitPythonConfig(PyConfig *config)
{
    config_init_defaults(config);

    config->_config_init = (int)_PyConfig_INIT_PYTHON;
    config->configure_c_stdio = 1;
    config->parse_argv = 1;
}


void
PyConfig_InitIsolatedConfig(PyConfig *config)
{
    config_init_defaults(config);

    config->_config_init = (int)_PyConfig_INIT_ISOLATED;
    config->isolated = 1;
    config->use_environment = 0;
    config->user_site_directory = 0;
    config->dev_mode = 0;
    config->install_signal_handlers = 0;
    config->use_hash_seed = 0;
    config->faulthandler = 0;
    config->tracemalloc = 0;
    config->pathconfig_warnings = 0;
#ifdef MS_WINDOWS
    config->legacy_windows_stdio = 0;
#endif
}


/* Copy str into *config_str (duplicate the string) */
PyStatus
PyConfig_SetString(PyConfig *config, wchar_t **config_str, const wchar_t *str)
{
    PyStatus status = _Py_PreInitializeFromConfig(config, NULL);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    wchar_t *str2;
    if (str != NULL) {
        str2 = _PyMem_RawWcsdup(str);
        if (str2 == NULL) {
            return _PyStatus_NO_MEMORY();
        }
    }
    else {
        str2 = NULL;
    }
    PyMem_RawFree(*config_str);
    *config_str = str2;
    return _PyStatus_OK();
}


static PyStatus
config_set_bytes_string(PyConfig *config, wchar_t **config_str,
                        const char *str, const char *decode_err_msg)
{
    PyStatus status = _Py_PreInitializeFromConfig(config, NULL);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    wchar_t *str2;
    if (str != NULL) {
        size_t len;
        str2 = Py_DecodeLocale(str, &len);
        if (str2 == NULL) {
            if (len == (size_t)-2) {
                return _PyStatus_ERR(decode_err_msg);
            }
            else {
                return  _PyStatus_NO_MEMORY();
            }
        }
    }
    else {
        str2 = NULL;
    }
    PyMem_RawFree(*config_str);
    *config_str = str2;
    return _PyStatus_OK();
}


#define CONFIG_SET_BYTES_STR(config, config_str, str, NAME) \
    config_set_bytes_string(config, config_str, str, "cannot decode " NAME)


/* Decode str using Py_DecodeLocale() and set the result into *config_str.
   Pre-initialize Python if needed to ensure that encodings are properly
   configured. */
PyStatus
PyConfig_SetBytesString(PyConfig *config, wchar_t **config_str,
                           const char *str)
{
    return CONFIG_SET_BYTES_STR(config, config_str, str, "string");
}


PyStatus
_PyConfig_Copy(PyConfig *config, const PyConfig *config2)
{
    PyStatus status;

    PyConfig_Clear(config);

#define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
#define COPY_WSTR_ATTR(ATTR) \
    do { \
        status = PyConfig_SetString(config, &config->ATTR, config2->ATTR); \
        if (_PyStatus_EXCEPTION(status)) { \
            return status; \
        } \
    } while (0)
#define COPY_WSTRLIST(LIST) \
    do { \
        if (_PyWideStringList_Copy(&config->LIST, &config2->LIST) < 0) { \
            return _PyStatus_NO_MEMORY(); \
        } \
    } while (0)

    COPY_ATTR(_config_init);
    COPY_ATTR(isolated);
    COPY_ATTR(use_environment);
    COPY_ATTR(dev_mode);
    COPY_ATTR(install_signal_handlers);
    COPY_ATTR(use_hash_seed);
    COPY_ATTR(hash_seed);
    COPY_ATTR(_install_importlib);
    COPY_ATTR(faulthandler);
    COPY_ATTR(tracemalloc);
    COPY_ATTR(import_time);
    COPY_ATTR(show_ref_count);
    COPY_ATTR(show_alloc_count);
    COPY_ATTR(dump_refs);
    COPY_ATTR(malloc_stats);

    COPY_WSTR_ATTR(pycache_prefix);
    COPY_WSTR_ATTR(pythonpath_env);
    COPY_WSTR_ATTR(home);
    COPY_WSTR_ATTR(program_name);

    COPY_ATTR(parse_argv);
    COPY_WSTRLIST(argv);
    COPY_WSTRLIST(warnoptions);
    COPY_WSTRLIST(xoptions);
    COPY_WSTRLIST(module_search_paths);
    COPY_ATTR(module_search_paths_set);

    COPY_WSTR_ATTR(executable);
    COPY_WSTR_ATTR(base_executable);
    COPY_WSTR_ATTR(prefix);
    COPY_WSTR_ATTR(base_prefix);
    COPY_WSTR_ATTR(exec_prefix);
    COPY_WSTR_ATTR(base_exec_prefix);

    COPY_ATTR(site_import);
    COPY_ATTR(bytes_warning);
    COPY_ATTR(inspect);
    COPY_ATTR(interactive);
    COPY_ATTR(optimization_level);
    COPY_ATTR(parser_debug);
    COPY_ATTR(write_bytecode);
    COPY_ATTR(verbose);
    COPY_ATTR(quiet);
    COPY_ATTR(user_site_directory);
    COPY_ATTR(configure_c_stdio);
    COPY_ATTR(buffered_stdio);
    COPY_WSTR_ATTR(filesystem_encoding);
    COPY_WSTR_ATTR(filesystem_errors);
    COPY_WSTR_ATTR(stdio_encoding);
    COPY_WSTR_ATTR(stdio_errors);
#ifdef MS_WINDOWS
    COPY_ATTR(legacy_windows_stdio);
#endif
    COPY_ATTR(skip_source_first_line);
    COPY_WSTR_ATTR(run_command);
    COPY_WSTR_ATTR(run_module);
    COPY_WSTR_ATTR(run_filename);
    COPY_WSTR_ATTR(check_hash_pycs_mode);
    COPY_ATTR(pathconfig_warnings);
    COPY_ATTR(_init_main);

#undef COPY_ATTR
#undef COPY_WSTR_ATTR
#undef COPY_WSTRLIST
    return _PyStatus_OK();
}


static PyObject *
config_as_dict(const PyConfig *config)
{
    PyObject *dict;

    dict = PyDict_New();
    if (dict == NULL) {
        return NULL;
    }

#define SET_ITEM(KEY, EXPR) \
        do { \
            PyObject *obj = (EXPR); \
            if (obj == NULL) { \
                goto fail; \
            } \
            int res = PyDict_SetItemString(dict, (KEY), obj); \
            Py_DECREF(obj); \
            if (res < 0) { \
                goto fail; \
            } \
        } while (0)
#define SET_ITEM_INT(ATTR) \
    SET_ITEM(#ATTR, PyLong_FromLong(config->ATTR))
#define SET_ITEM_UINT(ATTR) \
    SET_ITEM(#ATTR, PyLong_FromUnsignedLong(config->ATTR))
#define FROM_WSTRING(STR) \
    ((STR != NULL) ? \
        PyUnicode_FromWideChar(STR, -1) \
        : (Py_INCREF(Py_None), Py_None))
#define SET_ITEM_WSTR(ATTR) \
    SET_ITEM(#ATTR, FROM_WSTRING(config->ATTR))
#define SET_ITEM_WSTRLIST(LIST) \
    SET_ITEM(#LIST, _PyWideStringList_AsList(&config->LIST))

    SET_ITEM_INT(_config_init);
    SET_ITEM_INT(isolated);
    SET_ITEM_INT(use_environment);
    SET_ITEM_INT(dev_mode);
    SET_ITEM_INT(install_signal_handlers);
    SET_ITEM_INT(use_hash_seed);
    SET_ITEM_UINT(hash_seed);
    SET_ITEM_INT(faulthandler);
    SET_ITEM_INT(tracemalloc);
    SET_ITEM_INT(import_time);
    SET_ITEM_INT(show_ref_count);
    SET_ITEM_INT(show_alloc_count);
    SET_ITEM_INT(dump_refs);
    SET_ITEM_INT(malloc_stats);
    SET_ITEM_WSTR(filesystem_encoding);
    SET_ITEM_WSTR(filesystem_errors);
    SET_ITEM_WSTR(pycache_prefix);
    SET_ITEM_WSTR(program_name);
    SET_ITEM_INT(parse_argv);
    SET_ITEM_WSTRLIST(argv);
    SET_ITEM_WSTRLIST(xoptions);
    SET_ITEM_WSTRLIST(warnoptions);
    SET_ITEM_WSTR(pythonpath_env);
    SET_ITEM_WSTR(home);
    SET_ITEM_WSTRLIST(module_search_paths);
    SET_ITEM_WSTR(executable);
    SET_ITEM_WSTR(base_executable);
    SET_ITEM_WSTR(prefix);
    SET_ITEM_WSTR(base_prefix);
    SET_ITEM_WSTR(exec_prefix);
    SET_ITEM_WSTR(base_exec_prefix);
    SET_ITEM_INT(site_import);
    SET_ITEM_INT(bytes_warning);
    SET_ITEM_INT(inspect);
    SET_ITEM_INT(interactive);
    SET_ITEM_INT(optimization_level);
    SET_ITEM_INT(parser_debug);
    SET_ITEM_INT(write_bytecode);
    SET_ITEM_INT(verbose);
    SET_ITEM_INT(quiet);
    SET_ITEM_INT(user_site_directory);
    SET_ITEM_INT(configure_c_stdio);
    SET_ITEM_INT(buffered_stdio);
    SET_ITEM_WSTR(stdio_encoding);
    SET_ITEM_WSTR(stdio_errors);
#ifdef MS_WINDOWS
    SET_ITEM_INT(legacy_windows_stdio);
#endif
    SET_ITEM_INT(skip_source_first_line);
    SET_ITEM_WSTR(run_command);
    SET_ITEM_WSTR(run_module);
    SET_ITEM_WSTR(run_filename);
    SET_ITEM_INT(_install_importlib);
    SET_ITEM_WSTR(check_hash_pycs_mode);
    SET_ITEM_INT(pathconfig_warnings);
    SET_ITEM_INT(_init_main);

    return dict;

fail:
    Py_DECREF(dict);
    return NULL;

#undef FROM_WSTRING
#undef SET_ITEM
#undef SET_ITEM_INT
#undef SET_ITEM_UINT
#undef SET_ITEM_WSTR
#undef SET_ITEM_WSTRLIST
}


static const char*
config_get_env(const PyConfig *config, const char *name)
{
    return _Py_GetEnv(config->use_environment, name);
}


/* Get a copy of the environment variable as wchar_t*.
   Return 0 on success, but *dest can be NULL.
   Return -1 on memory allocation failure. Return -2 on decoding error. */
static PyStatus
config_get_env_dup(PyConfig *config,
                   wchar_t **dest,
                   wchar_t *wname, char *name,
                   const char *decode_err_msg)
{
    assert(*dest == NULL);
    assert(config->use_environment >= 0);

    if (!config->use_environment) {
        *dest = NULL;
        return _PyStatus_OK();
    }

#ifdef MS_WINDOWS
    const wchar_t *var = _wgetenv(wname);
    if (!var || var[0] == '\0') {
        *dest = NULL;
        return _PyStatus_OK();
    }

    return PyConfig_SetString(config, dest, var);
#else
    const char *var = getenv(name);
    if (!var || var[0] == '\0') {
        *dest = NULL;
        return _PyStatus_OK();
    }

    return config_set_bytes_string(config, dest, var, decode_err_msg);
#endif
}


#define CONFIG_GET_ENV_DUP(CONFIG, DEST, WNAME, NAME) \
    config_get_env_dup(CONFIG, DEST, WNAME, NAME, "cannot decode " NAME)


static void
config_get_global_vars(PyConfig *config)
{
    if (config->_config_init != _PyConfig_INIT_COMPAT) {
        /* Python and Isolated configuration ignore global variables */
        return;
    }

#define COPY_FLAG(ATTR, VALUE) \
        if (config->ATTR == -1) { \
            config->ATTR = VALUE; \
        }
#define COPY_NOT_FLAG(ATTR, VALUE) \
        if (config->ATTR == -1) { \
            config->ATTR = !(VALUE); \
        }

    COPY_FLAG(isolated, Py_IsolatedFlag);
    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
    COPY_FLAG(bytes_warning, Py_BytesWarningFlag);
    COPY_FLAG(inspect, Py_InspectFlag);
    COPY_FLAG(interactive, Py_InteractiveFlag);
    COPY_FLAG(optimization_level, Py_OptimizeFlag);
    COPY_FLAG(parser_debug, Py_DebugFlag);
    COPY_FLAG(verbose, Py_VerboseFlag);
    COPY_FLAG(quiet, Py_QuietFlag);
#ifdef MS_WINDOWS
    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
#endif
    COPY_NOT_FLAG(pathconfig_warnings, Py_FrozenFlag);

    COPY_NOT_FLAG(buffered_stdio, Py_UnbufferedStdioFlag);
    COPY_NOT_FLAG(site_import, Py_NoSiteFlag);
    COPY_NOT_FLAG(write_bytecode, Py_DontWriteBytecodeFlag);
    COPY_NOT_FLAG(user_site_directory, Py_NoUserSiteDirectory);

#undef COPY_FLAG
#undef COPY_NOT_FLAG
}


/* Set Py_xxx global configuration variables from 'config' configuration. */
static void
config_set_global_vars(const PyConfig *config)
{
#define COPY_FLAG(ATTR, VAR) \
        if (config->ATTR != -1) { \
            VAR = config->ATTR; \
        }
#define COPY_NOT_FLAG(ATTR, VAR) \
        if (config->ATTR != -1) { \
            VAR = !config->ATTR; \
        }

    COPY_FLAG(isolated, Py_IsolatedFlag);
    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
    COPY_FLAG(bytes_warning, Py_BytesWarningFlag);
    COPY_FLAG(inspect, Py_InspectFlag);
    COPY_FLAG(interactive, Py_InteractiveFlag);
    COPY_FLAG(optimization_level, Py_OptimizeFlag);
    COPY_FLAG(parser_debug, Py_DebugFlag);
    COPY_FLAG(verbose, Py_VerboseFlag);
    COPY_FLAG(quiet, Py_QuietFlag);
#ifdef MS_WINDOWS
    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
#endif
    COPY_NOT_FLAG(pathconfig_warnings, Py_FrozenFlag);

    COPY_NOT_FLAG(buffered_stdio, Py_UnbufferedStdioFlag);
    COPY_NOT_FLAG(site_import, Py_NoSiteFlag);
    COPY_NOT_FLAG(write_bytecode, Py_DontWriteBytecodeFlag);
    COPY_NOT_FLAG(user_site_directory, Py_NoUserSiteDirectory);

    /* Random or non-zero hash seed */
    Py_HashRandomizationFlag = (config->use_hash_seed == 0 ||
                                config->hash_seed != 0);

#undef COPY_FLAG
#undef COPY_NOT_FLAG
}


/* Get the program name: use PYTHONEXECUTABLE and __PYVENV_LAUNCHER__
   environment variables on macOS if available. */
static PyStatus
config_init_program_name(PyConfig *config)
{
    PyStatus status;

    /* If Py_SetProgramName() was called, use its value */
    const wchar_t *program_name = _Py_path_config.program_name;
    if (program_name != NULL) {
        config->program_name = _PyMem_RawWcsdup(program_name);
        if (config->program_name == NULL) {
            return _PyStatus_NO_MEMORY();
        }
        return _PyStatus_OK();
    }

#ifdef __APPLE__
    /* On MacOS X, when the Python interpreter is embedded in an
       application bundle, it gets executed by a bootstrapping script
       that does os.execve() with an argv[0] that's different from the
       actual Python executable. This is needed to keep the Finder happy,
       or rather, to work around Apple's overly strict requirements of
       the process name. However, we still need a usable sys.executable,
       so the actual executable path is passed in an environment variable.
       See Lib/plat-mac/bundlebuilder.py for details about the bootstrap
       script. */
    const char *p = config_get_env(config, "PYTHONEXECUTABLE");
    if (p != NULL) {
        status = CONFIG_SET_BYTES_STR(config, &config->program_name, p,
                                      "PYTHONEXECUTABLE environment variable");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
        return _PyStatus_OK();
    }
#ifdef WITH_NEXT_FRAMEWORK
    else {
        const char* pyvenv_launcher = getenv("__PYVENV_LAUNCHER__");
        if (pyvenv_launcher && *pyvenv_launcher) {
            /* Used by Mac/Tools/pythonw.c to forward
             * the argv0 of the stub executable
             */
            status = CONFIG_SET_BYTES_STR(config,
                                          &config->program_name,
                                          pyvenv_launcher,
                                          "__PYVENV_LAUNCHER__ environment variable");
            if (_PyStatus_EXCEPTION(status)) {
                return status;
            }
            return _PyStatus_OK();
        }
    }
#endif   /* WITH_NEXT_FRAMEWORK */
#endif   /* __APPLE__ */

    /* Use argv[0] if available and non-empty */
    const PyWideStringList *argv = &config->argv;
    if (argv->length >= 1 && argv->items[0][0] != L'\0') {
        config->program_name = _PyMem_RawWcsdup(argv->items[0]);
        if (config->program_name == NULL) {
            return _PyStatus_NO_MEMORY();
        }
        return _PyStatus_OK();
    }

    /* Last fall back: hardcoded name */
#ifdef MS_WINDOWS
    const wchar_t *default_program_name = L"python";
#else
    const wchar_t *default_program_name = L"python3";
#endif
    status = PyConfig_SetString(config, &config->program_name,
                                default_program_name);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }
    return _PyStatus_OK();
}

static PyStatus
config_init_executable(PyConfig *config)
{
    assert(config->executable == NULL);

    /* If Py_SetProgramFullPath() was called, use its value */
    const wchar_t *program_full_path = _Py_path_config.program_full_path;
    if (program_full_path != NULL) {
        PyStatus status = PyConfig_SetString(config,
                                             &config->executable,
                                             program_full_path);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
        return _PyStatus_OK();
    }
    return _PyStatus_OK();
}


static const wchar_t*
config_get_xoption(const PyConfig *config, wchar_t *name)
{
    return _Py_get_xoption(&config->xoptions, name);
}


static PyStatus
config_init_home(PyConfig *config)
{
    assert(config->home == NULL);

    /* If Py_SetPythonHome() was called, use its value */
    wchar_t *home = _Py_path_config.home;
    if (home) {
        PyStatus status = PyConfig_SetString(config, &config->home, home);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
        return _PyStatus_OK();
    }

    return CONFIG_GET_ENV_DUP(config, &config->home,
                              L"PYTHONHOME", "PYTHONHOME");
}


static PyStatus
config_init_hash_seed(PyConfig *config)
{
    const char *seed_text = config_get_env(config, "PYTHONHASHSEED");

    Py_BUILD_ASSERT(sizeof(_Py_HashSecret_t) == sizeof(_Py_HashSecret.uc));
    /* Convert a text seed to a numeric one */
    if (seed_text && strcmp(seed_text, "random") != 0) {
        const char *endptr = seed_text;
        unsigned long seed;
        errno = 0;
        seed = strtoul(seed_text, (char **)&endptr, 10);
        if (*endptr != '\0'
            || seed > 4294967295UL
            || (errno == ERANGE && seed == ULONG_MAX))
        {
            return _PyStatus_ERR("PYTHONHASHSEED must be \"random\" "
                                "or an integer in range [0; 4294967295]");
        }
        /* Use a specific hash */
        config->use_hash_seed = 1;
        config->hash_seed = seed;
    }
    else {
        /* Use a random hash */
        config->use_hash_seed = 0;
        config->hash_seed = 0;
    }
    return _PyStatus_OK();
}


static int
config_wstr_to_int(const wchar_t *wstr, int *result)
{
    const wchar_t *endptr = wstr;
    errno = 0;
    long value = wcstol(wstr, (wchar_t **)&endptr, 10);
    if (*endptr != '\0' || errno == ERANGE) {
        return -1;
    }
    if (value < INT_MIN || value > INT_MAX) {
        return -1;
    }

    *result = (int)value;
    return 0;
}


static PyStatus
config_read_env_vars(PyConfig *config)
{
    PyStatus status;
    int use_env = config->use_environment;

    /* Get environment variables */
    _Py_get_env_flag(use_env, &config->parser_debug, "PYTHONDEBUG");
    _Py_get_env_flag(use_env, &config->verbose, "PYTHONVERBOSE");
    _Py_get_env_flag(use_env, &config->optimization_level, "PYTHONOPTIMIZE");
    _Py_get_env_flag(use_env, &config->inspect, "PYTHONINSPECT");

    int dont_write_bytecode = 0;
    _Py_get_env_flag(use_env, &dont_write_bytecode, "PYTHONDONTWRITEBYTECODE");
    if (dont_write_bytecode) {
        config->write_bytecode = 0;
    }

    int no_user_site_directory = 0;
    _Py_get_env_flag(use_env, &no_user_site_directory, "PYTHONNOUSERSITE");
    if (no_user_site_directory) {
        config->user_site_directory = 0;
    }

    int unbuffered_stdio = 0;
    _Py_get_env_flag(use_env, &unbuffered_stdio, "PYTHONUNBUFFERED");
    if (unbuffered_stdio) {
        config->buffered_stdio = 0;
    }

#ifdef MS_WINDOWS
    _Py_get_env_flag(use_env, &config->legacy_windows_stdio,
                 "PYTHONLEGACYWINDOWSSTDIO");
#endif

    if (config_get_env(config, "PYTHONDUMPREFS")) {
        config->dump_refs = 1;
    }
    if (config_get_env(config, "PYTHONMALLOCSTATS")) {
        config->malloc_stats = 1;
    }

    if (config->pythonpath_env == NULL) {
        status = CONFIG_GET_ENV_DUP(config, &config->pythonpath_env,
                                    L"PYTHONPATH", "PYTHONPATH");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->use_hash_seed < 0) {
        status = config_init_hash_seed(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    return _PyStatus_OK();
}


static PyStatus
config_init_tracemalloc(PyConfig *config)
{
    int nframe;
    int valid;

    const char *env = config_get_env(config, "PYTHONTRACEMALLOC");
    if (env) {
        if (!_Py_str_to_int(env, &nframe)) {
            valid = (nframe >= 0);
        }
        else {
            valid = 0;
        }
        if (!valid) {
            return _PyStatus_ERR("PYTHONTRACEMALLOC: invalid number of frames");
        }
        config->tracemalloc = nframe;
    }

    const wchar_t *xoption = config_get_xoption(config, L"tracemalloc");
    if (xoption) {
        const wchar_t *sep = wcschr(xoption, L'=');
        if (sep) {
            if (!config_wstr_to_int(sep + 1, &nframe)) {
                valid = (nframe >= 0);
            }
            else {
                valid = 0;
            }
            if (!valid) {
                return _PyStatus_ERR("-X tracemalloc=NFRAME: "
                                     "invalid number of frames");
            }
        }
        else {
            /* -X tracemalloc behaves as -X tracemalloc=1 */
            nframe = 1;
        }
        config->tracemalloc = nframe;
    }
    return _PyStatus_OK();
}


static PyStatus
config_init_pycache_prefix(PyConfig *config)
{
    assert(config->pycache_prefix == NULL);

    const wchar_t *xoption = config_get_xoption(config, L"pycache_prefix");
    if (xoption) {
        const wchar_t *sep = wcschr(xoption, L'=');
        if (sep && wcslen(sep) > 1) {
            config->pycache_prefix = _PyMem_RawWcsdup(sep + 1);
            if (config->pycache_prefix == NULL) {
                return _PyStatus_NO_MEMORY();
            }
        }
        else {
            // PYTHONPYCACHEPREFIX env var ignored
            // if "-X pycache_prefix=" option is used
            config->pycache_prefix = NULL;
        }
        return _PyStatus_OK();
    }

    return CONFIG_GET_ENV_DUP(config, &config->pycache_prefix,
                              L"PYTHONPYCACHEPREFIX",
                              "PYTHONPYCACHEPREFIX");
}


static PyStatus
config_read_complex_options(PyConfig *config)
{
    /* More complex options configured by env var and -X option */
    if (config->faulthandler < 0) {
        if (config_get_env(config, "PYTHONFAULTHANDLER")
           || config_get_xoption(config, L"faulthandler")) {
            config->faulthandler = 1;
        }
    }
    if (config_get_env(config, "PYTHONPROFILEIMPORTTIME")
       || config_get_xoption(config, L"importtime")) {
        config->import_time = 1;
    }

    PyStatus status;
    if (config->tracemalloc < 0) {
        status = config_init_tracemalloc(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->pycache_prefix == NULL) {
        status = config_init_pycache_prefix(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }
    return _PyStatus_OK();
}


static const wchar_t *
config_get_stdio_errors(const PyConfig *config)
{
#ifndef MS_WINDOWS
    const char *loc = setlocale(LC_CTYPE, NULL);
    if (loc != NULL) {
        /* surrogateescape is the default in the legacy C and POSIX locales */
        if (strcmp(loc, "C") == 0 || strcmp(loc, "POSIX") == 0) {
            return L"surrogateescape";
        }

#ifdef PY_COERCE_C_LOCALE
        /* surrogateescape is the default in locale coercion target locales */
        if (_Py_IsLocaleCoercionTarget(loc)) {
            return L"surrogateescape";
        }
#endif
    }

    return L"strict";
#else
    /* On Windows, always use surrogateescape by default */
    return L"surrogateescape";
#endif
}


static PyStatus
config_get_locale_encoding(PyConfig *config, wchar_t **locale_encoding)
{
#ifdef MS_WINDOWS
    char encoding[20];
    PyOS_snprintf(encoding, sizeof(encoding), "cp%u", GetACP());
    return PyConfig_SetBytesString(config, locale_encoding, encoding);
#elif defined(_Py_FORCE_UTF8_LOCALE)
    return PyConfig_SetString(config, locale_encoding, L"utf-8");
#else
    const char *encoding = nl_langinfo(CODESET);
    if (!encoding || encoding[0] == '\0') {
        return _PyStatus_ERR("failed to get the locale encoding: "
                             "nl_langinfo(CODESET) failed");
    }
    /* nl_langinfo(CODESET) is decoded by Py_DecodeLocale() */
    return CONFIG_SET_BYTES_STR(config,
                                locale_encoding, encoding,
                                "nl_langinfo(CODESET)");
#endif
}


static PyStatus
config_init_stdio_encoding(PyConfig *config,
                           const PyPreConfig *preconfig)
{
    PyStatus status;

    /* If Py_SetStandardStreamEncoding() have been called, use these
        parameters. */
    if (config->stdio_encoding == NULL && _Py_StandardStreamEncoding != NULL) {
        status = CONFIG_SET_BYTES_STR(config, &config->stdio_encoding,
                                      _Py_StandardStreamEncoding,
                                      "_Py_StandardStreamEncoding");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->stdio_errors == NULL && _Py_StandardStreamErrors != NULL) {
        status = CONFIG_SET_BYTES_STR(config, &config->stdio_errors,
                                      _Py_StandardStreamErrors,
                                      "_Py_StandardStreamErrors");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->stdio_encoding != NULL && config->stdio_errors != NULL) {
        return _PyStatus_OK();
    }

    /* PYTHONIOENCODING environment variable */
    const char *opt = config_get_env(config, "PYTHONIOENCODING");
    if (opt) {
        char *pythonioencoding = _PyMem_RawStrdup(opt);
        if (pythonioencoding == NULL) {
            return _PyStatus_NO_MEMORY();
        }

        char *errors = strchr(pythonioencoding, ':');
        if (errors) {
            *errors = '\0';
            errors++;
            if (!errors[0]) {
                errors = NULL;
            }
        }

        /* Does PYTHONIOENCODING contain an encoding? */
        if (pythonioencoding[0]) {
            if (config->stdio_encoding == NULL) {
                status = CONFIG_SET_BYTES_STR(config, &config->stdio_encoding,
                                              pythonioencoding,
                                              "PYTHONIOENCODING environment variable");
                if (_PyStatus_EXCEPTION(status)) {
                    PyMem_RawFree(pythonioencoding);
                    return status;
                }
            }

            /* If the encoding is set but not the error handler,
               use "strict" error handler by default.
               PYTHONIOENCODING=latin1 behaves as
               PYTHONIOENCODING=latin1:strict. */
            if (!errors) {
                errors = "strict";
            }
        }

        if (config->stdio_errors == NULL && errors != NULL) {
            status = CONFIG_SET_BYTES_STR(config, &config->stdio_errors,
                                          errors,
                                          "PYTHONIOENCODING environment variable");
            if (_PyStatus_EXCEPTION(status)) {
                PyMem_RawFree(pythonioencoding);
                return status;
            }
        }

        PyMem_RawFree(pythonioencoding);
    }

    /* UTF-8 Mode uses UTF-8/surrogateescape */
    if (preconfig->utf8_mode) {
        if (config->stdio_encoding == NULL) {
            status = PyConfig_SetString(config, &config->stdio_encoding,
                                        L"utf-8");
            if (_PyStatus_EXCEPTION(status)) {
                return status;
            }
        }
        if (config->stdio_errors == NULL) {
            status = PyConfig_SetString(config, &config->stdio_errors,
                                        L"surrogateescape");
            if (_PyStatus_EXCEPTION(status)) {
                return status;
            }
        }
    }

    /* Choose the default error handler based on the current locale. */
    if (config->stdio_encoding == NULL) {
        status = config_get_locale_encoding(config, &config->stdio_encoding);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }
    if (config->stdio_errors == NULL) {
        const wchar_t *errors = config_get_stdio_errors(config);
        assert(errors != NULL);

        status = PyConfig_SetString(config, &config->stdio_errors, errors);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    return _PyStatus_OK();
}


static PyStatus
config_init_fs_encoding(PyConfig *config, const PyPreConfig *preconfig)
{
    PyStatus status;

    if (config->filesystem_encoding == NULL) {
#ifdef _Py_FORCE_UTF8_FS_ENCODING
        status = PyConfig_SetString(config, &config->filesystem_encoding, L"utf-8");
#else

#ifdef MS_WINDOWS
        if (preconfig->legacy_windows_fs_encoding) {
            /* Legacy Windows filesystem encoding: mbcs/replace */
            status = PyConfig_SetString(config, &config->filesystem_encoding,
                                        L"mbcs");
        }
        else
#endif
        if (preconfig->utf8_mode) {
            status = PyConfig_SetString(config, &config->filesystem_encoding,
                                        L"utf-8");
        }
#ifndef MS_WINDOWS
        else if (_Py_GetForceASCII()) {
            status = PyConfig_SetString(config, &config->filesystem_encoding,
                                        L"ascii");
        }
#endif
        else {
#ifdef MS_WINDOWS
            /* Windows defaults to utf-8/surrogatepass (PEP 529). */
            status = PyConfig_SetString(config, &config->filesystem_encoding,
                                        L"utf-8");
#else
            status = config_get_locale_encoding(config,
                                                &config->filesystem_encoding);
#endif
        }
#endif   /* !_Py_FORCE_UTF8_FS_ENCODING */

        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->filesystem_errors == NULL) {
        const wchar_t *errors;
#ifdef MS_WINDOWS
        if (preconfig->legacy_windows_fs_encoding) {
            errors = L"replace";
        }
        else {
            errors = L"surrogatepass";
        }
#else
        errors = L"surrogateescape";
#endif
        status = PyConfig_SetString(config, &config->filesystem_errors, errors);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }
    return _PyStatus_OK();
}


static PyStatus
config_read(PyConfig *config)
{
    PyStatus status;
    const PyPreConfig *preconfig = &_PyRuntime.preconfig;

    if (config->use_environment) {
        status = config_read_env_vars(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    /* -X options */
    if (config_get_xoption(config, L"showrefcount")) {
        config->show_ref_count = 1;
    }
    if (config_get_xoption(config, L"showalloccount")) {
        config->show_alloc_count = 1;
    }

    status = config_read_complex_options(config);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    if (config->home == NULL) {
        status = config_init_home(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->executable == NULL) {
        status = config_init_executable(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->_install_importlib) {
        status = _PyConfig_InitPathConfig(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    /* default values */
    if (config->dev_mode) {
        if (config->faulthandler < 0) {
            config->faulthandler = 1;
        }
    }
    if (config->faulthandler < 0) {
        config->faulthandler = 0;
    }
    if (config->tracemalloc < 0) {
        config->tracemalloc = 0;
    }
    if (config->use_hash_seed < 0) {
        config->use_hash_seed = 0;
        config->hash_seed = 0;
    }

    if (config->filesystem_encoding == NULL || config->filesystem_errors == NULL) {
        status = config_init_fs_encoding(config, preconfig);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    status = config_init_stdio_encoding(config, preconfig);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    if (config->argv.length < 1) {
        /* Ensure at least one (empty) argument is seen */
        status = PyWideStringList_Append(&config->argv, L"");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->check_hash_pycs_mode == NULL) {
        status = PyConfig_SetString(config, &config->check_hash_pycs_mode,
                                    L"default");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->configure_c_stdio < 0) {
        config->configure_c_stdio = 1;
    }

    return _PyStatus_OK();
}


static void
config_init_stdio(const PyConfig *config)
{
#if defined(MS_WINDOWS) || defined(__CYGWIN__)
    /* don't translate newlines (\r\n <=> \n) */
    _setmode(fileno(stdin), O_BINARY);
    _setmode(fileno(stdout), O_BINARY);
    _setmode(fileno(stderr), O_BINARY);
#endif

    if (!config->buffered_stdio) {
#ifdef HAVE_SETVBUF
        setvbuf(stdin,  (char *)NULL, _IONBF, BUFSIZ);
        setvbuf(stdout, (char *)NULL, _IONBF, BUFSIZ);
        setvbuf(stderr, (char *)NULL, _IONBF, BUFSIZ);
#else /* !HAVE_SETVBUF */
        setbuf(stdin,  (char *)NULL);
        setbuf(stdout, (char *)NULL);
        setbuf(stderr, (char *)NULL);
#endif /* !HAVE_SETVBUF */
    }
    else if (config->interactive) {
#ifdef MS_WINDOWS
        /* Doesn't have to have line-buffered -- use unbuffered */
        /* Any set[v]buf(stdin, ...) screws up Tkinter :-( */
        setvbuf(stdout, (char *)NULL, _IONBF, BUFSIZ);
#else /* !MS_WINDOWS */
#ifdef HAVE_SETVBUF
        setvbuf(stdin,  (char *)NULL, _IOLBF, BUFSIZ);
        setvbuf(stdout, (char *)NULL, _IOLBF, BUFSIZ);
#endif /* HAVE_SETVBUF */
#endif /* !MS_WINDOWS */
        /* Leave stderr alone - it should be unbuffered anyway. */
    }
}


/* Write the configuration:

   - set Py_xxx global configuration variables
   - initialize C standard streams (stdin, stdout, stderr) */
void
_PyConfig_Write(const PyConfig *config, _PyRuntimeState *runtime)
{
    config_set_global_vars(config);

    if (config->configure_c_stdio) {
        config_init_stdio(config);
    }

    /* Write the new pre-configuration into _PyRuntime */
    PyPreConfig *preconfig = &runtime->preconfig;
    preconfig->isolated = config->isolated;
    preconfig->use_environment = config->use_environment;
    preconfig->dev_mode = config->dev_mode;
}


/* --- PyConfig command line parser -------------------------- */

static void
config_usage(int error, const wchar_t* program)
{
    FILE *f = error ? stderr : stdout;

    fprintf(f, usage_line, program);
    if (error)
        fprintf(f, "Try `python -h' for more information.\n");
    else {
        fputs(usage_1, f);
        fputs(usage_2, f);
        fputs(usage_3, f);
        fprintf(f, usage_4, (wint_t)DELIM);
        fprintf(f, usage_5, (wint_t)DELIM, PYTHONHOMEHELP);
        fputs(usage_6, f);
    }
}


/* Parse the command line arguments */
static PyStatus
config_parse_cmdline(PyConfig *config, PyWideStringList *warnoptions,
                     Py_ssize_t *opt_index)
{
    PyStatus status;
    const PyWideStringList *argv = &config->argv;
    int print_version = 0;
    const wchar_t* program = config->program_name;

    _PyOS_ResetGetOpt();
    do {
        int longindex = -1;
        int c = _PyOS_GetOpt(argv->length, argv->items, &longindex);
        if (c == EOF) {
            break;
        }

        if (c == 'c') {
            if (config->run_command == NULL) {
                /* -c is the last option; following arguments
                   that look like options are left for the
                   command to interpret. */
                size_t len = wcslen(_PyOS_optarg) + 1 + 1;
                wchar_t *command = PyMem_RawMalloc(sizeof(wchar_t) * len);
                if (command == NULL) {
                    return _PyStatus_NO_MEMORY();
                }
                memcpy(command, _PyOS_optarg, (len - 2) * sizeof(wchar_t));
                command[len - 2] = '\n';
                command[len - 1] = 0;
                config->run_command = command;
            }
            break;
        }

        if (c == 'm') {
            /* -m is the last option; following arguments
               that look like options are left for the
               module to interpret. */
            if (config->run_module == NULL) {
                config->run_module = _PyMem_RawWcsdup(_PyOS_optarg);
                if (config->run_module == NULL) {
                    return _PyStatus_NO_MEMORY();
                }
            }
            break;
        }

        switch (c) {
        case 0:
            // Handle long option.
            assert(longindex == 0); // Only one long option now.
            if (wcscmp(_PyOS_optarg, L"always") == 0
                || wcscmp(_PyOS_optarg, L"never") == 0
                || wcscmp(_PyOS_optarg, L"default") == 0)
            {
                status = PyConfig_SetString(config, &config->check_hash_pycs_mode,
                                            _PyOS_optarg);
                if (_PyStatus_EXCEPTION(status)) {
                    return status;
                }
            } else {
                fprintf(stderr, "--check-hash-based-pycs must be one of "
                        "'default', 'always', or 'never'\n");
                config_usage(1, program);
                return _PyStatus_EXIT(2);
            }
            break;

        case 'b':
            config->bytes_warning++;
            break;

        case 'd':
            config->parser_debug++;
            break;

        case 'i':
            config->inspect++;
            config->interactive++;
            break;

        case 'E':
        case 'I':
        case 'X':
            /* option handled by _PyPreCmdline_Read() */
            break;

        /* case 'J': reserved for Jython */

        case 'O':
            config->optimization_level++;
            break;

        case 'B':
            config->write_bytecode = 0;
            break;

        case 's':
            config->user_site_directory = 0;
            break;

        case 'S':
            config->site_import = 0;
            break;

        case 't':
            /* ignored for backwards compatibility */
            break;

        case 'u':
            config->buffered_stdio = 0;
            break;

        case 'v':
            config->verbose++;
            break;

        case 'x':
            config->skip_source_first_line = 1;
            break;

        case 'h':
        case '?':
            config_usage(0, program);
            return _PyStatus_EXIT(0);

        case 'V':
            print_version++;
            break;

        case 'W':
            status = PyWideStringList_Append(warnoptions, _PyOS_optarg);
            if (_PyStatus_EXCEPTION(status)) {
                return status;
            }
            break;

        case 'q':
            config->quiet++;
            break;

        case 'R':
            config->use_hash_seed = 0;
            break;

        /* This space reserved for other options */

        default:
            /* unknown argument: parsing failed */
            config_usage(1, program);
            return _PyStatus_EXIT(2);
        }
    } while (1);

    if (print_version) {
        printf("Python %s\n",
                (print_version >= 2) ? Py_GetVersion() : PY_VERSION);
        return _PyStatus_EXIT(0);
    }

    if (config->run_command == NULL && config->run_module == NULL
        && _PyOS_optind < argv->length
        && wcscmp(argv->items[_PyOS_optind], L"-") != 0
        && config->run_filename == NULL)
    {
        config->run_filename = _PyMem_RawWcsdup(argv->items[_PyOS_optind]);
        if (config->run_filename == NULL) {
            return _PyStatus_NO_MEMORY();
        }
    }

    if (config->run_command != NULL || config->run_module != NULL) {
        /* Backup _PyOS_optind */
        _PyOS_optind--;
    }

    *opt_index = _PyOS_optind;

    return _PyStatus_OK();
}


#ifdef MS_WINDOWS
#  define WCSTOK wcstok_s
#else
#  define WCSTOK wcstok
#endif

/* Get warning options from PYTHONWARNINGS environment variable. */
static PyStatus
config_init_env_warnoptions(PyConfig *config, PyWideStringList *warnoptions)
{
    PyStatus status;
    /* CONFIG_GET_ENV_DUP requires dest to be initialized to NULL */
    wchar_t *env = NULL;
    status = CONFIG_GET_ENV_DUP(config, &env,
                             L"PYTHONWARNINGS", "PYTHONWARNINGS");
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    /* env var is not set or is empty */
    if (env == NULL) {
        return _PyStatus_OK();
    }


    wchar_t *warning, *context = NULL;
    for (warning = WCSTOK(env, L",", &context);
         warning != NULL;
         warning = WCSTOK(NULL, L",", &context))
    {
        status = PyWideStringList_Append(warnoptions, warning);
        if (_PyStatus_EXCEPTION(status)) {
            PyMem_RawFree(env);
            return status;
        }
    }
    PyMem_RawFree(env);
    return _PyStatus_OK();
}


static PyStatus
warnoptions_append(PyConfig *config, PyWideStringList *options,
                   const wchar_t *option)
{
    /* config_init_warnoptions() add existing config warnoptions at the end:
       ensure that the new option is not already present in this list to
       prevent change the options order whne config_init_warnoptions() is
       called twice. */
    if (_PyWideStringList_Find(&config->warnoptions, option)) {
        /* Already present: do nothing */
        return _PyStatus_OK();
    }
    if (_PyWideStringList_Find(options, option)) {
        /* Already present: do nothing */
        return _PyStatus_OK();
    }
    return PyWideStringList_Append(options, option);
}


static PyStatus
warnoptions_extend(PyConfig *config, PyWideStringList *options,
                   const PyWideStringList *options2)
{
    const Py_ssize_t len = options2->length;
    wchar_t *const *items = options2->items;

    for (Py_ssize_t i = 0; i < len; i++) {
        PyStatus status = warnoptions_append(config, options, items[i]);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }
    return _PyStatus_OK();
}


static PyStatus
config_init_warnoptions(PyConfig *config,
                        const PyWideStringList *cmdline_warnoptions,
                        const PyWideStringList *env_warnoptions,
                        const PyWideStringList *sys_warnoptions)
{
    PyStatus status;
    PyWideStringList options = _PyWideStringList_INIT;

    /* Priority of warnings options, lowest to highest:
     *
     * - any implicit filters added by _warnings.c/warnings.py
     * - PyConfig.dev_mode: "default" filter
     * - PYTHONWARNINGS environment variable
     * - '-W' command line options
     * - PyConfig.bytes_warning ('-b' and '-bb' command line options):
     *   "default::BytesWarning" or "error::BytesWarning" filter
     * - early PySys_AddWarnOption() calls
     * - PyConfig.warnoptions
     *
     * PyConfig.warnoptions is copied to sys.warnoptions. Since the warnings
     * module works on the basis of "the most recently added filter will be
     * checked first", we add the lowest precedence entries first so that later
     * entries override them.
     */

    if (config->dev_mode) {
        status = warnoptions_append(config, &options, L"default");
        if (_PyStatus_EXCEPTION(status)) {
            goto error;
        }
    }

    status = warnoptions_extend(config, &options, env_warnoptions);
    if (_PyStatus_EXCEPTION(status)) {
        goto error;
    }

    status = warnoptions_extend(config, &options, cmdline_warnoptions);
    if (_PyStatus_EXCEPTION(status)) {
        goto error;
    }

    /* If the bytes_warning_flag isn't set, bytesobject.c and bytearrayobject.c
     * don't even try to emit a warning, so we skip setting the filter in that
     * case.
     */
    if (config->bytes_warning) {
        const wchar_t *filter;
        if (config->bytes_warning> 1) {
            filter = L"error::BytesWarning";
        }
        else {
            filter = L"default::BytesWarning";
        }
        status = warnoptions_append(config, &options, filter);
        if (_PyStatus_EXCEPTION(status)) {
            goto error;
        }
    }

    status = warnoptions_extend(config, &options, sys_warnoptions);
    if (_PyStatus_EXCEPTION(status)) {
        goto error;
    }

    /* Always add all PyConfig.warnoptions options */
    status = _PyWideStringList_Extend(&options, &config->warnoptions);
    if (_PyStatus_EXCEPTION(status)) {
        goto error;
    }

    _PyWideStringList_Clear(&config->warnoptions);
    config->warnoptions = options;
    return _PyStatus_OK();

error:
    _PyWideStringList_Clear(&options);
    return status;
}


static PyStatus
config_update_argv(PyConfig *config, Py_ssize_t opt_index)
{
    const PyWideStringList *cmdline_argv = &config->argv;
    PyWideStringList config_argv = _PyWideStringList_INIT;

    /* Copy argv to be able to modify it (to force -c/-m) */
    if (cmdline_argv->length <= opt_index) {
        /* Ensure at least one (empty) argument is seen */
        PyStatus status = PyWideStringList_Append(&config_argv, L"");
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }
    else {
        PyWideStringList slice;
        slice.length = cmdline_argv->length - opt_index;
        slice.items = &cmdline_argv->items[opt_index];
        if (_PyWideStringList_Copy(&config_argv, &slice) < 0) {
            return _PyStatus_NO_MEMORY();
        }
    }
    assert(config_argv.length >= 1);

    wchar_t *arg0 = NULL;
    if (config->run_command != NULL) {
        /* Force sys.argv[0] = '-c' */
        arg0 = L"-c";
    }
    else if (config->run_module != NULL) {
        /* Force sys.argv[0] = '-m'*/
        arg0 = L"-m";
    }

    if (arg0 != NULL) {
        arg0 = _PyMem_RawWcsdup(arg0);
        if (arg0 == NULL) {
            _PyWideStringList_Clear(&config_argv);
            return _PyStatus_NO_MEMORY();
        }

        PyMem_RawFree(config_argv.items[0]);
        config_argv.items[0] = arg0;
    }

    _PyWideStringList_Clear(&config->argv);
    config->argv = config_argv;
    return _PyStatus_OK();
}


static PyStatus
core_read_precmdline(PyConfig *config, _PyPreCmdline *precmdline)
{
    PyStatus status;

    if (config->parse_argv) {
        if (_PyWideStringList_Copy(&precmdline->argv, &config->argv) < 0) {
            return _PyStatus_NO_MEMORY();
        }
    }

    PyPreConfig preconfig;

    status = _PyPreConfig_InitFromPreConfig(&preconfig, &_PyRuntime.preconfig);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    _PyPreConfig_GetConfig(&preconfig, config);

    status = _PyPreCmdline_Read(precmdline, &preconfig);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    status = _PyPreCmdline_SetConfig(precmdline, config);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }
    return _PyStatus_OK();
}


/* Get run_filename absolute path */
static PyStatus
config_run_filename_abspath(PyConfig *config)
{
    if (!config->run_filename) {
        return _PyStatus_OK();
    }

#ifndef MS_WINDOWS
    if (_Py_isabs(config->run_filename)) {
        /* path is already absolute */
        return _PyStatus_OK();
    }
#endif

    wchar_t *abs_filename;
    if (_Py_abspath(config->run_filename, &abs_filename) < 0) {
        /* failed to get the absolute path of the command line filename:
           ignore the error, keep the relative path */
        return _PyStatus_OK();
    }
    if (abs_filename == NULL) {
        return _PyStatus_NO_MEMORY();
    }

    PyMem_RawFree(config->run_filename);
    config->run_filename = abs_filename;
    return _PyStatus_OK();
}


static PyStatus
config_read_cmdline(PyConfig *config)
{
    PyStatus status;
    PyWideStringList cmdline_warnoptions = _PyWideStringList_INIT;
    PyWideStringList env_warnoptions = _PyWideStringList_INIT;
    PyWideStringList sys_warnoptions = _PyWideStringList_INIT;

    if (config->parse_argv < 0) {
        config->parse_argv = 1;
    }

    if (config->program_name == NULL) {
        status = config_init_program_name(config);
        if (_PyStatus_EXCEPTION(status)) {
            return status;
        }
    }

    if (config->parse_argv) {
        Py_ssize_t opt_index;
        status = config_parse_cmdline(config, &cmdline_warnoptions, &opt_index);
        if (_PyStatus_EXCEPTION(status)) {
            goto done;
        }

        status = config_run_filename_abspath(config);
        if (_PyStatus_EXCEPTION(status)) {
            goto done;
        }

        status = config_update_argv(config, opt_index);
        if (_PyStatus_EXCEPTION(status)) {
            goto done;
        }
    }
    else {
        status = config_run_filename_abspath(config);
        if (_PyStatus_EXCEPTION(status)) {
            goto done;
        }
    }

    if (config->use_environment) {
        status = config_init_env_warnoptions(config, &env_warnoptions);
        if (_PyStatus_EXCEPTION(status)) {
            goto done;
        }
    }

    /* Handle early PySys_AddWarnOption() calls */
    status = _PySys_ReadPreinitWarnOptions(&sys_warnoptions);
    if (_PyStatus_EXCEPTION(status)) {
        goto done;
    }

    status = config_init_warnoptions(config,
                                     &cmdline_warnoptions,
                                     &env_warnoptions,
                                     &sys_warnoptions);
    if (_PyStatus_EXCEPTION(status)) {
        goto done;
    }

    status = _PyStatus_OK();

done:
    _PyWideStringList_Clear(&cmdline_warnoptions);
    _PyWideStringList_Clear(&env_warnoptions);
    _PyWideStringList_Clear(&sys_warnoptions);
    return status;
}


PyStatus
_PyConfig_SetPyArgv(PyConfig *config, const _PyArgv *args)
{
    PyStatus status = _Py_PreInitializeFromConfig(config, args);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    return _PyArgv_AsWstrList(args, &config->argv);
}


/* Set config.argv: decode argv using Py_DecodeLocale(). Pre-initialize Python
   if needed to ensure that encodings are properly configured. */
PyStatus
PyConfig_SetBytesArgv(PyConfig *config, Py_ssize_t argc, char * const *argv)
{
    _PyArgv args = {
        .argc = argc,
        .use_bytes_argv = 1,
        .bytes_argv = argv,
        .wchar_argv = NULL};
    return _PyConfig_SetPyArgv(config, &args);
}


PyStatus
PyConfig_SetArgv(PyConfig *config, Py_ssize_t argc, wchar_t * const *argv)
{
    _PyArgv args = {
        .argc = argc,
        .use_bytes_argv = 0,
        .bytes_argv = NULL,
        .wchar_argv = argv};
    return _PyConfig_SetPyArgv(config, &args);
}


PyStatus
PyConfig_SetWideStringList(PyConfig *config, PyWideStringList *list,
                           Py_ssize_t length, wchar_t **items)
{
    PyStatus status = _Py_PreInitializeFromConfig(config, NULL);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    PyWideStringList list2 = {.length = length, .items = items};
    if (_PyWideStringList_Copy(list, &list2) < 0) {
        return _PyStatus_NO_MEMORY();
    }
    return _PyStatus_OK();
}


/* Read the configuration into PyConfig from:

   * Command line arguments
   * Environment variables
   * Py_xxx global configuration variables

   The only side effects are to modify config and to call _Py_SetArgcArgv(). */
PyStatus
PyConfig_Read(PyConfig *config)
{
    PyStatus status;
    PyWideStringList orig_argv = _PyWideStringList_INIT;

    status = _Py_PreInitializeFromConfig(config, NULL);
    if (_PyStatus_EXCEPTION(status)) {
        return status;
    }

    config_get_global_vars(config);

    if (_PyWideStringList_Copy(&orig_argv, &config->argv) < 0) {
        return _PyStatus_NO_MEMORY();
    }

    _PyPreCmdline precmdline = _PyPreCmdline_INIT;
    status = core_read_precmdline(config, &precmdline);
    if (_PyStatus_EXCEPTION(status)) {
        goto done;
    }

    assert(config->isolated >= 0);
    if (config->isolated) {
        config->use_environment = 0;
        config->user_site_directory = 0;
    }

    status = config_read_cmdline(config);
    if (_PyStatus_EXCEPTION(status)) {
        goto done;
    }

    /* Handle early PySys_AddXOption() calls */
    status = _PySys_ReadPreinitXOptions(config);
    if (_PyStatus_EXCEPTION(status)) {
        goto done;
    }

    status = config_read(config);
    if (_PyStatus_EXCEPTION(status)) {
        goto done;
    }

    if (_Py_SetArgcArgv(orig_argv.length, orig_argv.items) < 0) {
        status = _PyStatus_NO_MEMORY();
        goto done;
    }

    /* Check config consistency */
    assert(config->isolated >= 0);
    assert(config->use_environment >= 0);
    assert(config->dev_mode >= 0);
    assert(config->install_signal_handlers >= 0);
    assert(config->use_hash_seed >= 0);
    assert(config->faulthandler >= 0);
    assert(config->tracemalloc >= 0);
    assert(config->site_import >= 0);
    assert(config->bytes_warning >= 0);
    assert(config->inspect >= 0);
    assert(config->interactive >= 0);
    assert(config->optimization_level >= 0);
    assert(config->parser_debug >= 0);
    assert(config->write_bytecode >= 0);
    assert(config->verbose >= 0);
    assert(config->quiet >= 0);
    assert(config->user_site_directory >= 0);
    assert(config->parse_argv >= 0);
    assert(config->configure_c_stdio >= 0);
    assert(config->buffered_stdio >= 0);
    assert(config->program_name != NULL);
    assert(_PyWideStringList_CheckConsistency(&config->argv));
    /* sys.argv must be non-empty: empty argv is replaced with [''] */
    assert(config->argv.length >= 1);
    assert(_PyWideStringList_CheckConsistency(&config->xoptions));
    assert(_PyWideStringList_CheckConsistency(&config->warnoptions));
    assert(_PyWideStringList_CheckConsistency(&config->module_search_paths));
    if (config->_install_importlib) {
        assert(config->module_search_paths_set != 0);
        /* don't check config->module_search_paths */
        assert(config->executable != NULL);
        assert(config->base_executable != NULL);
        assert(config->prefix != NULL);
        assert(config->base_prefix != NULL);
        assert(config->exec_prefix != NULL);
        assert(config->base_exec_prefix != NULL);
    }
    assert(config->filesystem_encoding != NULL);
    assert(config->filesystem_errors != NULL);
    assert(config->stdio_encoding != NULL);
    assert(config->stdio_errors != NULL);
#ifdef MS_WINDOWS
    assert(config->legacy_windows_stdio >= 0);
#endif
    /* -c and -m options are exclusive */
    assert(!(config->run_command != NULL && config->run_module != NULL));
    assert(config->check_hash_pycs_mode != NULL);
    assert(config->_install_importlib >= 0);
    assert(config->pathconfig_warnings >= 0);

    status = _PyStatus_OK();

done:
    _PyWideStringList_Clear(&orig_argv);
    _PyPreCmdline_Clear(&precmdline);
    return status;
}


PyObject*
_Py_GetConfigsAsDict(void)
{
    PyObject *result = NULL;
    PyObject *dict = NULL;

    result = PyDict_New();
    if (result == NULL) {
        goto error;
    }

    /* global result */
    dict = _Py_GetGlobalVariablesAsDict();
    if (dict == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(result, "global_config", dict) < 0) {
        goto error;
    }
    Py_CLEAR(dict);

    /* pre config */
    PyInterpreterState *interp = _PyInterpreterState_Get();
    const PyPreConfig *pre_config = &_PyRuntime.preconfig;
    dict = _PyPreConfig_AsDict(pre_config);
    if (dict == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(result, "pre_config", dict) < 0) {
        goto error;
    }
    Py_CLEAR(dict);

    /* core config */
    const PyConfig *config = &interp->config;
    dict = config_as_dict(config);
    if (dict == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(result, "config", dict) < 0) {
        goto error;
    }
    Py_CLEAR(dict);

    return result;

error:
    Py_XDECREF(result);
    Py_XDECREF(dict);
    return NULL;
}


static void
init_dump_ascii_wstr(const wchar_t *str)
{
    if (str == NULL) {
        PySys_WriteStderr("(not set)");
        return;
    }

    PySys_WriteStderr("'");
    for (; *str != L'\0'; str++) {
        wchar_t ch = *str;
        if (ch == L'\'') {
            PySys_WriteStderr("\\'");
        } else if (0x20 <= ch && ch < 0x7f) {
            PySys_WriteStderr("%lc", ch);
        }
        else if (ch <= 0xff) {
            PySys_WriteStderr("\\x%02x", ch);
        }
#if SIZEOF_WCHAR_T > 2
        else if (ch > 0xffff) {
            PySys_WriteStderr("\\U%08x", ch);
        }
#endif
        else {
            PySys_WriteStderr("\\u%04x", ch);
        }
    }
    PySys_WriteStderr("'");
}


/* Dump the Python path configuration into sys.stderr */
void
_Py_DumpPathConfig(PyThreadState *tstate)
{
    PyObject *exc_type, *exc_value, *exc_tb;
    _PyErr_Fetch(tstate, &exc_type, &exc_value, &exc_tb);

    PySys_WriteStderr("Python path configuration:\n");

#define DUMP_CONFIG(NAME, FIELD) \
        do { \
            PySys_WriteStderr("  " NAME " = "); \
            init_dump_ascii_wstr(config->FIELD); \
            PySys_WriteStderr("\n"); \
        } while (0)

    PyConfig *config = &tstate->interp->config;
    DUMP_CONFIG("PYTHONHOME", home);
    DUMP_CONFIG("PYTHONPATH", pythonpath_env);
    DUMP_CONFIG("program name", program_name);
    PySys_WriteStderr("  isolated = %i\n", config->isolated);
    PySys_WriteStderr("  environment = %i\n", config->use_environment);
    PySys_WriteStderr("  user site = %i\n", config->user_site_directory);
    PySys_WriteStderr("  import site = %i\n", config->site_import);
#undef DUMP_CONFIG

#define DUMP_SYS(NAME) \
        do { \
            obj = PySys_GetObject(#NAME); \
            PySys_FormatStderr("  sys.%s = ", #NAME); \
            if (obj != NULL) { \
                PySys_FormatStderr("%A", obj); \
            } \
            else { \
                PySys_WriteStderr("(not set)"); \
            } \
            PySys_FormatStderr("\n"); \
        } while (0)

    PyObject *obj;
    DUMP_SYS(_base_executable);
    DUMP_SYS(base_prefix);
    DUMP_SYS(base_exec_prefix);
    DUMP_SYS(executable);
    DUMP_SYS(prefix);
    DUMP_SYS(exec_prefix);
#undef DUMP_SYS

    PyObject *sys_path = PySys_GetObject("path");  /* borrowed reference */
    if (sys_path != NULL && PyList_Check(sys_path)) {
        PySys_WriteStderr("  sys.path = [\n");
        Py_ssize_t len = PyList_GET_SIZE(sys_path);
        for (Py_ssize_t i=0; i < len; i++) {
            PyObject *path = PyList_GET_ITEM(sys_path, i);
            PySys_FormatStderr("    %A,\n", path);
        }
        PySys_WriteStderr("  ]\n");
    }

    _PyErr_Restore(tstate, exc_type, exc_value, exc_tb);
}