initconfig.c

#include "Python.h"
#include "pycore_fileutils.h"     // _Py_HasFileSystemDefaultEncodeErrors
#include "pycore_getopt.h"        // _PyOS_GetOpt()
#include "pycore_initconfig.h"    // _PyStatus_OK()
#include "pycore_interp.h"        // _PyInterpreterState.runtime
#include "pycore_long.h"          // _PY_LONG_MAX_STR_DIGITS_THRESHOLD
#include "pycore_pathconfig.h"    // _Py_path_config
#include "pycore_pyerrors.h"      // _PyErr_GetRaisedException()
#include "pycore_pylifecycle.h"   // _Py_PreInitializeFromConfig()
#include "pycore_pymem.h"         // _PyMem_SetDefaultAllocator()
#include "pycore_pystate.h"       // _PyThreadState_GET()
#include "pycore_pystats.h"       // _Py_StatsOn()

#include "osdefs.h"               // DELIM

#include <locale.h>               // setlocale()
#include <stdlib.h>               // getenv()
#if defined(MS_WINDOWS) || defined(__CYGWIN__)
#  ifdef HAVE_IO_H
#    include <io.h>
#  endif
#  ifdef HAVE_FCNTL_H
#    include <fcntl.h>            // O_BINARY
#  endif
#endif

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

typedef enum {
    PyConfig_MEMBER_INT = 0,
    PyConfig_MEMBER_UINT = 1,
    PyConfig_MEMBER_ULONG = 2,
    PyConfig_MEMBER_BOOL = 3,

    PyConfig_MEMBER_WSTR = 10,
    PyConfig_MEMBER_WSTR_OPT = 11,
    PyConfig_MEMBER_WSTR_LIST = 12,
} PyConfigMemberType;

typedef struct {
    const char *name;
    size_t offset;
    PyConfigMemberType type;
} PyConfigSpec;

#define SPEC(MEMBER, TYPE) \
    {#MEMBER, offsetof(PyConfig, MEMBER), PyConfig_MEMBER_##TYPE}

// Update _test_embed_set_config when adding new members
static const PyConfigSpec PYCONFIG_SPEC[] = {
    SPEC(_config_init, UINT),
    SPEC(isolated, BOOL),
    SPEC(use_environment, BOOL),
    SPEC(dev_mode, BOOL),
    SPEC(install_signal_handlers, BOOL),
    SPEC(use_hash_seed, BOOL),
    SPEC(hash_seed, ULONG),
    SPEC(faulthandler, BOOL),
    SPEC(tracemalloc, UINT),
    SPEC(perf_profiling, BOOL),
    SPEC(import_time, BOOL),
    SPEC(code_debug_ranges, BOOL),
    SPEC(show_ref_count, BOOL),
    SPEC(dump_refs, BOOL),
    SPEC(dump_refs_file, WSTR_OPT),
    SPEC(malloc_stats, BOOL),
    SPEC(filesystem_encoding, WSTR),
    SPEC(filesystem_errors, WSTR),
    SPEC(pycache_prefix, WSTR_OPT),
    SPEC(parse_argv, BOOL),
    SPEC(orig_argv, WSTR_LIST),
    SPEC(argv, WSTR_LIST),
    SPEC(xoptions, WSTR_LIST),
    SPEC(warnoptions, WSTR_LIST),
    SPEC(site_import, BOOL),
    SPEC(bytes_warning, UINT),
    SPEC(warn_default_encoding, BOOL),
    SPEC(inspect, BOOL),
    SPEC(interactive, BOOL),
    SPEC(optimization_level, UINT),
    SPEC(parser_debug, BOOL),
    SPEC(write_bytecode, BOOL),
    SPEC(verbose, UINT),
    SPEC(quiet, BOOL),
    SPEC(user_site_directory, BOOL),
    SPEC(configure_c_stdio, BOOL),
    SPEC(buffered_stdio, BOOL),
    SPEC(stdio_encoding, WSTR),
    SPEC(stdio_errors, WSTR),
#ifdef MS_WINDOWS
    SPEC(legacy_windows_stdio, BOOL),
#endif
    SPEC(check_hash_pycs_mode, WSTR),
    SPEC(use_frozen_modules, BOOL),
    SPEC(safe_path, BOOL),
    SPEC(int_max_str_digits, INT),
    SPEC(cpu_count, INT),
#ifdef Py_GIL_DISABLED
    SPEC(enable_gil, INT),
#endif
    SPEC(pathconfig_warnings, BOOL),
    SPEC(program_name, WSTR),
    SPEC(pythonpath_env, WSTR_OPT),
    SPEC(home, WSTR_OPT),
    SPEC(platlibdir, WSTR),
    SPEC(sys_path_0, WSTR_OPT),
    SPEC(module_search_paths_set, BOOL),
    SPEC(module_search_paths, WSTR_LIST),
    SPEC(stdlib_dir, WSTR_OPT),
    SPEC(executable, WSTR_OPT),
    SPEC(base_executable, WSTR_OPT),
    SPEC(prefix, WSTR_OPT),
    SPEC(base_prefix, WSTR_OPT),
    SPEC(exec_prefix, WSTR_OPT),
    SPEC(base_exec_prefix, WSTR_OPT),
    SPEC(skip_source_first_line, BOOL),
    SPEC(run_command, WSTR_OPT),
    SPEC(run_module, WSTR_OPT),
    SPEC(run_filename, WSTR_OPT),
    SPEC(_install_importlib, BOOL),
    SPEC(_init_main, BOOL),
    SPEC(_is_python_build, BOOL),
#ifdef Py_STATS
    SPEC(_pystats, BOOL),
#endif
#ifdef Py_DEBUG
    SPEC(run_presite, WSTR_OPT),
#endif
    {NULL, 0, 0},
};

#undef SPEC


/* --- 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 help message */
/* Lines sorted by option name; keep in sync with usage_envvars* below */
static const char usage_help[] = "\
Options (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     : turn on parser debugging output (for experts only, only works on\n\
         debug builds); also PYTHONDEBUG=x\n\
-E     : ignore PYTHON* environment variables (such as PYTHONPATH)\n\
-h     : print this help message and exit (also -? or --help)\n\
-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\
-P     : don't prepend a potentially unsafe path to sys.path; also\n\
         PYTHONSAFEPATH\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\
-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\n\
--check-hash-based-pycs always|default|never:\n\
         control how Python invalidates hash-based .pyc files\n\
--help-env: print help about Python environment variables and exit\n\
--help-xoptions: print help about implementation-specific -X options and exit\n\
--help-all: print complete help information and exit\n\
\n\
Arguments:\n\
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\
";

static const char usage_xoptions[] = "\
The following implementation-specific options are available:\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\n\
         the 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\n\
         in a traceback of a trace.  Use -X tracemalloc=NFRAME to start\n\
         tracing with a traceback limit of NFRAME frames\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\n\
         multi-threaded application.\n\
         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\n\
         the developer mode:\n\
          * Add default warning filter, as -W default\n\
          * Install debug hooks on memory allocators: see the\n\
            PyMem_SetupDebugHooks() C function\n\
          * Enable the faulthandler module to dump the Python traceback on\n\
            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\n\
         default locale-aware mode.  -X utf8=0 explicitly disables UTF-8 mode\n\
         (even when it would otherwise activate automatically)\n\
-X pycache_prefix=PATH: enable writing .pyc files to a parallel tree rooted\n\
         at the given directory instead of to the code tree\n\
-X warn_default_encoding: enable opt-in EncodingWarning for 'encoding=None'\n\
-X no_debug_ranges: disable the inclusion of the tables mapping extra location\n\
         information (end line, start column offset and end column offset) to\n\
         every instruction in code objects.  This is useful when smaller code\n\
         objects and pyc files are desired as well as suppressing the extra\n\
         visual location indicators when the interpreter displays tracebacks.\n\
-X perf: activate support for the Linux \"perf\" profiler by activating the\n\
         \"perf\" trampoline.  When this option is activated, the Linux \"perf\"\n\
         profiler will be able to report Python calls.  This option is only\n\
         available on some platforms and will do nothing if is not supported\n\
         on the current system.  The default value is \"off\".\n\
-X frozen_modules=[on|off]: whether or not frozen modules should be used.\n\
         The default is \"on\" (or \"off\" if you are running a local build).\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\n\
         data.  The default is sys.int_info.default_max_str_digits.\n\
         0 disables.\n\
-X cpu_count=[n|default]: Override the return value of os.cpu_count(),\n\
         os.process_cpu_count(), and multiprocessing.cpu_count().  This can\n\
         help users who need to limit resources in a container."
#ifdef Py_STATS
"\n\
-X pystats: Enable pystats collection at startup."
#endif
#ifdef Py_DEBUG
"\n\
-X presite=package.module: import this module before site.py is run."
#endif
;

/* Envvars that don't have equivalent command-line options are listed first */
static const char usage_envvars[] =
"Environment variables that change behavior:\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"
"PYTHONHOME      : alternate <prefix> directory (or <prefix>%lc<exec_prefix>).\n"
"                  The default module search path uses %s.\n"
"PYTHONPLATLIBDIR: override sys.platlibdir.\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"
"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\n"
"                  set to an integer in the range [0,4294967295] to get hash\n"
"                  values with a predictable seed.\n"
"PYTHONINTMAXSTRDIGITS: limits the maximum digit characters in an int value\n"
"                  when converting from a string and when converting an int\n"
"                  back to a str.  A value of 0 disables the limit.\n"
"                  Conversions to or from bases 2, 4, 8, 16, and 32 are never\n"
"                  limited.\n"
"PYTHONMALLOC    : set the Python memory allocators and/or install debug hooks\n"
"                  on Python memory allocators.  Use PYTHONMALLOC=debug to\n"
"                  install debug hooks.\n"
"PYTHONCOERCECLOCALE: if this variable is set to 0, it disables the locale\n"
"                  coercion behavior.  Use PYTHONCOERCECLOCALE=warn to request\n"
"                  display of locale coercion and locale compatibility warnings\n"
"                  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\n"
"                  choice.\n"
"PYTHON_CPU_COUNT: Overrides the return value of os.process_cpu_count(),\n"
"                  os.cpu_count(), and multiprocessing.cpu_count() if set to\n"
"                  a positive integer.\n"
#ifdef Py_GIL_DISABLED
"PYTHON_GIL      : When set to 0, disables the GIL.\n"
#endif
"PYTHONDEVMODE   : enable the development mode.\n"
"PYTHONPYCACHEPREFIX: root directory for bytecode cache (pyc) files.\n"
"PYTHONWARNDEFAULTENCODING: enable opt-in EncodingWarning for 'encoding=None'.\n"
"PYTHONNODEBUGRANGES: if this variable is set, it disables the inclusion of\n"
"                  the tables mapping extra location information (end line,\n"
"                  start column offset and end column offset) to every\n"
"                  instruction in code objects.  This is useful when smaller\n"
"                  code objects and pyc files are desired as well as\n"
"                  suppressing the extra visual location indicators when the\n"
"                  interpreter displays tracebacks.\n"
"PYTHON_FROZEN_MODULES: if this variable is set, it determines whether or not\n"
"                  frozen modules should be used.  The default is \"on\" (or\n"
"                  \"off\" if you are running a local build).\n"
"PYTHON_COLORS   : if this variable is set to 1, the interpreter will colorize\n"
"                  various kinds of output.  Setting it to 0 deactivates\n"
"                  this behavior.\n"
"PYTHON_HISTORY  : the location of a .python_history file.\n"
"\n"
"These variables have equivalent command-line options (see --help for details):\n"
"PYTHONDEBUG     : enable parser debug mode (-d)\n"
"PYTHONDONTWRITEBYTECODE: don't write .pyc files (-B)\n"
"PYTHONINSPECT   : inspect interactively after running script (-i)\n"
"PYTHONINTMAXSTRDIGITS: limit max digit characters in an int value\n"
"                  (-X int_max_str_digits=number)\n"
"PYTHONNOUSERSITE: disable user site directory (-s)\n"
"PYTHONOPTIMIZE  : enable level 1 optimizations (-O)\n"
"PYTHONSAFEPATH  : don't prepend a potentially unsafe path to sys.path.\n"
"PYTHONUNBUFFERED: disable stdout/stderr buffering (-u)\n"
"PYTHONVERBOSE   : trace import statements (-v)\n"
"PYTHONWARNINGS=arg: warning control (-W arg)\n"
#ifdef Py_STATS
"PYTHONSTATS     : turns on statistics gathering\n"
#endif
#ifdef Py_DEBUG
"PYTHON_PRESITE=pkg.mod: import this module before site.py is run\n"
#endif
;

#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; /* Previously, was used by Py_FdIsInteractive() */
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)
{
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
    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_NewRef(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
_Py_COMP_DIAG_POP
}

char*
Py_GETENV(const char *name)
{
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
    if (Py_IgnoreEnvironmentFlag) {
        return NULL;
    }
    return getenv(name);
_Py_COMP_DIAG_POP
}

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

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

PyStatus PyStatus_Error(const char *err_msg)
{
    assert(err_msg != NULL);
    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); }

void
_PyErr_SetFromPyStatus(PyStatus status)
{
    if (!_PyStatus_IS_ERROR(status)) {
        PyErr_Format(PyExc_SystemError,
                     "_PyErr_SetFromPyStatus() status is not an error");
        return;
    }

    const char *err_msg = status.err_msg;
    if (err_msg == NULL || strlen(err_msg) == 0) {
        PyErr_Format(PyExc_SystemError,
                     "_PyErr_SetFromPyStatus() status has no error message");
        return;
    }

    if (strcmp(err_msg, _PyStatus_NO_MEMORY_ERRMSG) == 0) {
        PyErr_NoMemory();
        return;
    }

    const char *func = status.func;
    if (func) {
        PyErr_Format(PyExc_RuntimeError, "%s: %s", func, err_msg);
    }
    else {
        PyErr_Format(PyExc_RuntimeError, "%s", err_msg);
    }
}


/* --- 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_GetArgcArgv() ------------------------------------------- */

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

    _PyWideStringList_Clear(&_PyRuntime.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);

    // XXX _PyRuntime.orig_argv only gets cleared by Py_Main(),
    // so it currently leaks for embedders.
    res = _PyWideStringList_Copy(&_PyRuntime.orig_argv, &argv_list);

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


// _PyConfig_Write() calls _Py_SetArgcArgv() with PyConfig.orig_argv.
void
Py_GetArgcArgv(int *argc, wchar_t ***argv)
{
    *argc = (int)_PyRuntime.orig_argv.length;
    *argv = _PyRuntime.orig_argv.items;
}


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

#define MAX_HASH_SEED 4294967295UL


#ifndef NDEBUG
static int
config_check_consistency(const PyConfig *config)
{
    /* 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->hash_seed <= MAX_HASH_SEED);
    assert(config->faulthandler >= 0);
    assert(config->tracemalloc >= 0);
    assert(config->import_time >= 0);
    assert(config->code_debug_ranges >= 0);
    assert(config->show_ref_count >= 0);
    assert(config->dump_refs >= 0);
    assert(config->malloc_stats >= 0);
    assert(config->site_import >= 0);
    assert(config->bytes_warning >= 0);
    assert(config->warn_default_encoding >= 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(_PyWideStringList_CheckConsistency(&config->orig_argv));
    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));
    assert(config->module_search_paths_set >= 0);
    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);
    assert(config->_is_python_build >= 0);
    assert(config->safe_path >= 0);
    assert(config->int_max_str_digits >= 0);
    // cpu_count can be -1 if the user doesn't override it.
    assert(config->cpu_count != 0);
    // config->use_frozen_modules is initialized later
    // by _PyConfig_InitImportConfig().
#ifdef Py_STATS
    assert(config->_pystats >= 0);
#endif
    return 1;
}
#endif


/* 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->stdlib_dir);

    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->platlibdir);
    CLEAR(config->sys_path_0);

    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);
#ifdef Py_DEBUG
    CLEAR(config->run_presite);
#endif

    _PyWideStringList_Clear(&config->orig_argv);
#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->perf_profiling = -1;
    config->module_search_paths_set = 0;
    config->parse_argv = 0;
    config->site_import = -1;
    config->bytes_warning = -1;
    config->warn_default_encoding = 0;
    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
#ifdef Py_DEBUG
    config->use_frozen_modules = 0;
#else
    config->use_frozen_modules = 1;
#endif
    config->safe_path = 0;
    config->int_max_str_digits = -1;
    config->_is_python_build = 0;
    config->code_debug_ranges = 1;
    config->cpu_count = -1;
#ifdef Py_GIL_DISABLED
    config->enable_gil = _PyConfig_GIL_DEFAULT;
#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->perf_profiling = 0;
    config->int_max_str_digits = _PY_LONG_DEFAULT_MAX_STR_DIGITS;
    config->safe_path = 1;
    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