initconfig.c

#include "Python.h"
#include "osdefs.h"       /* DELIM */
#include "pycore_fileutils.h"
#include "pycore_getopt.h"
#include "pycore_initconfig.h"
#include "pycore_long.h"          // _PY_LONG_MAX_STR_DIGITS_THRESHOLD
#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\
         -X int_max_str_digits=number: limit the size of int<->str conversions.\n\
             This helps avoid denial of service attacks when parsing untrusted data.\n\
             The default is sys.int_info.default_max_str_digits.  0 disables.\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"
"PYTHONINTMAXSTRDIGITS: limits the maximum digit characters in an int value\n"
"   when converting from a string and when converting an int back to a str.\n"
"   A value of 0 disables the limit.  Conversions to or from bases 2, 4, 8,\n"
"   16, and 32 are never limited.\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
}

/* Excluded from public struct PyConfig for backporting reasons. */
/* default to unconfigured, _PyLong_Init() does the rest */
int _Py_global_config_int_max_str_digits = -1;


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();