bpo-34170: Add Python/coreconfig.c for _PyCoreConfig (GH-8607)

* Add Include/coreconfig.h
* Move config_*() and _PyCoreConfig_*() functions from Modules/main.c
  to a new Python/coreconfig.c file.
* Inline _Py_ReadHashSeed() into config_init_hash_seed()
* Move global configuration variables to coreconfig.c

5 files changed, 964 insertions, 76 deletions

diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 7bb5687..4b12048 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -11,29 +11,6 @@
 
 #include <ctype.h>
 
-/* The default encoding used by the platform file system APIs
-   Can remain NULL for all platforms that don't have such a concept
-
-   Don't forget to modify PyUnicode_DecodeFSDefault() if you touch any of the
-   values for Py_FileSystemDefaultEncoding!
-*/
-#if defined(__APPLE__)
-const char *Py_FileSystemDefaultEncoding = "utf-8";
-int Py_HasFileSystemDefaultEncoding = 1;
-#elif defined(MS_WINDOWS)
-/* may be changed by initfsencoding(), but should never be free()d */
-const char *Py_FileSystemDefaultEncoding = "utf-8";
-int Py_HasFileSystemDefaultEncoding = 1;
-#else
-const char *Py_FileSystemDefaultEncoding = NULL; /* set by initfsencoding() */
-int Py_HasFileSystemDefaultEncoding = 0;
-#endif
-const char *Py_FileSystemDefaultEncodeErrors = "surrogateescape";
-/* UTF-8 mode (PEP 540): if equals to 1, use the UTF-8 encoding, and change
-   stdin and stdout error handler to "surrogateescape". It is equal to
-   -1 by default: unknown, will be set by Py_Main() */
-int Py_UTF8Mode = -1;
-
 _Py_IDENTIFIER(__builtins__);
 _Py_IDENTIFIER(__dict__);
 _Py_IDENTIFIER(__prepare__);
diff --git a/Python/bootstrap_hash.c b/Python/bootstrap_hash.c
index 073b2ea..7b187f1 100644
--- a/Python/bootstrap_hash.c
+++ b/Python/bootstrap_hash.c
@@ -538,35 +538,6 @@ _PyOS_URandomNonblock(void *buffer, Py_ssize_t size)
     return pyurandom(buffer, size, 0, 1);
 }
 
-int
-_Py_ReadHashSeed(const char *seed_text,
-                 int *use_hash_seed,
-                 unsigned long *hash_seed)
-{
-    Py_BUILD_ASSERT(sizeof(_Py_HashSecret_t) == sizeof(_Py_HashSecret.uc));
-    /* Convert a text seed to a numeric one */
-    if (seed_text && *seed_text != '\0' && strcmp(seed_text, "random") != 0) {
-        const char *endptr = seed_text;
-        unsigned long seed;
-        seed = strtoul(seed_text, (char **)&endptr, 10);
-        if (*endptr != '\0'
-            || seed > 4294967295UL
-            || (errno == ERANGE && seed == ULONG_MAX))
-        {
-            return -1;
-        }
-        /* Use a specific hash */
-        *use_hash_seed = 1;
-        *hash_seed = seed;
-    }
-    else {
-        /* Use a random hash */
-        *use_hash_seed = 0;
-        *hash_seed = 0;
-    }
-    return 0;
-}
-
 
 _PyInitError
 _Py_HashRandomization_Init(const _PyCoreConfig *config)
diff --git a/Python/coreconfig.c b/Python/coreconfig.c
new file mode 100644
index 0000000..7dabe5f
--- /dev/null
+++ b/Python/coreconfig.c
@@ -0,0 +1,964 @@
+#include "Python.h"
+#include "internal/import.h"
+#include "internal/pystate.h"
+
+
+#define DECODE_LOCALE_ERR(NAME, LEN) \
+    (((LEN) == -2) \
+     ? _Py_INIT_USER_ERR("cannot decode " NAME) \
+     : _Py_INIT_NO_MEMORY())
+
+
+/* Global configuration variables */
+
+/* The default encoding used by the platform file system APIs
+   Can remain NULL for all platforms that don't have such a concept
+
+   Don't forget to modify PyUnicode_DecodeFSDefault() if you touch any of the
+   values for Py_FileSystemDefaultEncoding!
+*/
+#if defined(__APPLE__)
+const char *Py_FileSystemDefaultEncoding = "utf-8";
+int Py_HasFileSystemDefaultEncoding = 1;
+#elif defined(MS_WINDOWS)
+/* may be changed by initfsencoding(), but should never be free()d */
+const char *Py_FileSystemDefaultEncoding = "utf-8";
+int Py_HasFileSystemDefaultEncoding = 1;
+#else
+const char *Py_FileSystemDefaultEncoding = NULL; /* set by initfsencoding() */
+int Py_HasFileSystemDefaultEncoding = 0;
+#endif
+const char *Py_FileSystemDefaultEncodeErrors = "surrogateescape";
+/* UTF-8 mode (PEP 540): if equals to 1, use the UTF-8 encoding, and change
+   stdin and stdout error handler to "surrogateescape". It is equal to
+   -1 by default: unknown, will be set by Py_Main() */
+int Py_UTF8Mode = -1;
+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
+const char *_Py_CheckHashBasedPycsMode = "default";
+
+
+void
+_Py_wstrlist_clear(int len, wchar_t **list)
+{
+    for (int i=0; i < len; i++) {
+        PyMem_RawFree(list[i]);
+    }
+    PyMem_RawFree(list);
+}
+
+
+wchar_t**
+_Py_wstrlist_copy(int len, wchar_t **list)
+{
+    assert((len > 0 && list != NULL) || len == 0);
+    size_t size = len * sizeof(list[0]);
+    wchar_t **list_copy = PyMem_RawMalloc(size);
+    for (int i=0; i < len; i++) {
+        wchar_t* arg = _PyMem_RawWcsdup(list[i]);
+        if (arg == NULL) {
+            _Py_wstrlist_clear(i, list);
+            return NULL;
+        }
+        list_copy[i] = arg;
+    }
+    return list_copy;
+}
+
+
+/* Free memory allocated in config, but don't clear all attributes */
+void
+_PyCoreConfig_Clear(_PyCoreConfig *config)
+{
+#define CLEAR(ATTR) \
+    do { \
+        PyMem_RawFree(ATTR); \
+        ATTR = NULL; \
+    } while (0)
+#define CLEAR_WSTRLIST(LEN, LIST) \
+    do { \
+        _Py_wstrlist_clear(LEN, LIST); \
+        LEN = 0; \
+        LIST = NULL; \
+    } while (0)
+
+    CLEAR(config->pycache_prefix);
+    CLEAR(config->module_search_path_env);
+    CLEAR(config->home);
+    CLEAR(config->program_name);
+    CLEAR(config->program);
+
+    CLEAR_WSTRLIST(config->argc, config->argv);
+    config->argc = -1;
+
+    CLEAR_WSTRLIST(config->nwarnoption, config->warnoptions);
+    CLEAR_WSTRLIST(config->nxoption, config->xoptions);
+    CLEAR_WSTRLIST(config->nmodule_search_path, config->module_search_paths);
+    config->nmodule_search_path = -1;
+
+    CLEAR(config->executable);
+    CLEAR(config->prefix);
+    CLEAR(config->base_prefix);
+    CLEAR(config->exec_prefix);
+#ifdef MS_WINDOWS
+    CLEAR(config->dll_path);
+#endif
+    CLEAR(config->base_exec_prefix);
+#undef CLEAR
+#undef CLEAR_WSTRLIST
+}
+
+
+int
+_PyCoreConfig_Copy(_PyCoreConfig *config, const _PyCoreConfig *config2)
+{
+    _PyCoreConfig_Clear(config);
+
+#define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
+#define COPY_STR_ATTR(ATTR) \
+    do { \
+        if (config2->ATTR != NULL) { \
+            config->ATTR = _PyMem_RawWcsdup(config2->ATTR); \
+            if (config->ATTR == NULL) { \
+                return -1; \
+            } \
+        } \
+    } while (0)
+#define COPY_WSTRLIST(LEN, LIST) \
+    do { \
+        if (config2->LIST != NULL) { \
+            config->LIST = _Py_wstrlist_copy(config2->LEN, config2->LIST); \
+            if (config->LIST == NULL) { \
+                return -1; \
+            } \
+        } \
+        config->LEN = config2->LEN; \
+    } while (0)
+
+    COPY_ATTR(install_signal_handlers);
+    COPY_ATTR(use_environment);
+    COPY_ATTR(use_hash_seed);
+    COPY_ATTR(hash_seed);
+    COPY_ATTR(_install_importlib);
+    COPY_ATTR(allocator);
+    COPY_ATTR(dev_mode);
+    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_ATTR(coerce_c_locale);
+    COPY_ATTR(coerce_c_locale_warn);
+    COPY_ATTR(utf8_mode);
+
+    COPY_STR_ATTR(pycache_prefix);
+    COPY_STR_ATTR(module_search_path_env);
+    COPY_STR_ATTR(home);
+    COPY_STR_ATTR(program_name);
+    COPY_STR_ATTR(program);
+
+    COPY_WSTRLIST(argc, argv);
+    COPY_WSTRLIST(nwarnoption, warnoptions);
+    COPY_WSTRLIST(nxoption, xoptions);
+    COPY_WSTRLIST(nmodule_search_path, module_search_paths);
+
+    COPY_STR_ATTR(executable);
+    COPY_STR_ATTR(prefix);
+    COPY_STR_ATTR(base_prefix);
+    COPY_STR_ATTR(exec_prefix);
+#ifdef MS_WINDOWS
+    COPY_STR_ATTR(dll_path);
+#endif
+    COPY_STR_ATTR(base_exec_prefix);
+
+    COPY_ATTR(isolated);
+    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(buffered_stdio);
+#ifdef MS_WINDOWS
+    COPY_ATTR(legacy_windows_fs_encoding);
+    COPY_ATTR(legacy_windows_stdio);
+#endif
+    COPY_ATTR(_check_hash_pycs_mode);
+    COPY_ATTR(_frozen);
+
+#undef COPY_ATTR
+#undef COPY_STR_ATTR
+#undef COPY_WSTRLIST
+    return 0;
+}
+
+
+const char*
+_PyCoreConfig_GetEnv(const _PyCoreConfig *config, const char *name)
+{
+    assert(config->use_environment >= 0);
+
+    if (!config->use_environment) {
+        return NULL;
+    }
+
+    const char *var = getenv(name);
+    if (var && var[0] != '\0') {
+        return var;
+    }
+    else {
+        return NULL;
+    }
+}
+
+
+int
+_PyCoreConfig_GetEnvDup(const _PyCoreConfig *config,
+                        wchar_t **dest,
+                        wchar_t *wname, char *name)
+{
+    assert(config->use_environment >= 0);
+
+    if (!config->use_environment) {
+        *dest = NULL;
+        return 0;
+    }
+
+#ifdef MS_WINDOWS
+    const wchar_t *var = _wgetenv(wname);
+    if (!var || var[0] == '\0') {
+        *dest = NULL;
+        return 0;
+    }
+
+    wchar_t *copy = _PyMem_RawWcsdup(var);
+    if (copy == NULL) {
+        return -1;
+    }
+
+    *dest = copy;
+#else
+    const char *var = getenv(name);
+    if (!var || var[0] == '\0') {
+        *dest = NULL;
+        return 0;
+    }
+
+    size_t len;
+    wchar_t *wvar = Py_DecodeLocale(var, &len);
+    if (!wvar) {
+        if (len == (size_t)-2) {
+            return -2;
+        }
+        else {
+            return -1;
+        }
+    }
+    *dest = wvar;
+#endif
+    return 0;
+}
+
+
+void
+_PyCoreConfig_GetGlobalConfig(_PyCoreConfig *config)
+{
+#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(utf8_mode, Py_UTF8Mode);
+    COPY_FLAG(isolated, Py_IsolatedFlag);
+    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_fs_encoding, Py_LegacyWindowsFSEncodingFlag);
+    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
+#endif
+    COPY_FLAG(_frozen, Py_FrozenFlag);
+
+    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
+    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);
+
+    if (config->_check_hash_pycs_mode == NULL) {
+        config->_check_hash_pycs_mode = _Py_CheckHashBasedPycsMode;
+    }
+
+#undef COPY_FLAG
+#undef COPY_NOT_FLAG
+}
+
+
+/* Set Py_xxx global configuration variables from 'config' configuration. */
+void
+_PyCoreConfig_SetGlobalConfig(const _PyCoreConfig *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(utf8_mode, Py_UTF8Mode);
+    COPY_FLAG(isolated, Py_IsolatedFlag);
+    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_fs_encoding, Py_LegacyWindowsFSEncodingFlag);
+    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
+#endif
+
+    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
+    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);
+
+    if (config->_check_hash_pycs_mode != NULL) {
+        _Py_CheckHashBasedPycsMode = config->_check_hash_pycs_mode;
+    }
+
+    /* 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 _PyInitError
+config_init_program_name(_PyCoreConfig *config)
+{
+    /* 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 _Py_INIT_NO_MEMORY();
+        }
+        return _Py_INIT_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/bundlebuiler.py for details about the bootstrap
+       script. */
+    const char *p = _PyCoreConfig_GetEnv(config, "PYTHONEXECUTABLE");
+    if (p != NULL) {
+        size_t len;
+        wchar_t* program_name = Py_DecodeLocale(p, &len);
+        if (program_name == NULL) {
+            return DECODE_LOCALE_ERR("PYTHONEXECUTABLE environment "
+                                     "variable", (Py_ssize_t)len);
+        }
+        config->program_name = program_name;
+        return _Py_INIT_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
+             */
+            size_t len;
+            wchar_t* program_name = Py_DecodeLocale(pyvenv_launcher, &len);
+            if (program_name == NULL) {
+                return DECODE_LOCALE_ERR("__PYVENV_LAUNCHER__ environment "
+                                         "variable", (Py_ssize_t)len);
+            }
+            config->program_name = program_name;
+            return _Py_INIT_OK();
+        }
+    }
+#endif   /* WITH_NEXT_FRAMEWORK */
+#endif   /* __APPLE__ */
+
+    /* Use argv[0] by default, if available */
+    if (config->program != NULL) {
+        config->program_name = _PyMem_RawWcsdup(config->program);
+        if (config->program_name == NULL) {
+            return _Py_INIT_NO_MEMORY();
+        }
+        return _Py_INIT_OK();
+    }
+
+    /* Last fall back: hardcoded string */
+#ifdef MS_WINDOWS
+    const wchar_t *default_program_name = L"python";
+#else
+    const wchar_t *default_program_name = L"python3";
+#endif
+    config->program_name = _PyMem_RawWcsdup(default_program_name);
+    if (config->program_name == NULL) {
+        return _Py_INIT_NO_MEMORY();
+    }
+    return _Py_INIT_OK();
+}
+
+
+static const wchar_t*
+config_get_xoption(const _PyCoreConfig *config, wchar_t *name)
+{
+    int nxoption = config->nxoption;
+    wchar_t **xoptions = config->xoptions;
+    for (int i=0; i < nxoption; i++) {
+        wchar_t *option = xoptions[i];
+        size_t len;
+        wchar_t *sep = wcschr(option, L'=');
+        if (sep != NULL) {
+            len = (sep - option);
+        }
+        else {
+            len = wcslen(option);
+        }
+        if (wcsncmp(option, name, len) == 0 && name[len] == L'\0') {
+            return option;
+        }
+    }
+    return NULL;
+}
+
+
+static _PyInitError
+config_init_home(_PyCoreConfig *config)
+{
+    wchar_t *home;
+
+    /* If Py_SetPythonHome() was called, use its value */
+    home = _Py_path_config.home;
+    if (home) {
+        config->home = _PyMem_RawWcsdup(home);
+        if (config->home == NULL) {
+            return _Py_INIT_NO_MEMORY();
+        }
+        return _Py_INIT_OK();
+    }
+
+    int res = _PyCoreConfig_GetEnvDup(config, &home,
+                                      L"PYTHONHOME", "PYTHONHOME");
+    if (res < 0) {
+        return DECODE_LOCALE_ERR("PYTHONHOME", res);
+    }
+    config->home = home;
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_hash_seed(_PyCoreConfig *config)
+{
+    const char *seed_text = _PyCoreConfig_GetEnv(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 _Py_INIT_USER_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 _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_utf8_mode(_PyCoreConfig *config)
+{
+    const wchar_t *xopt = config_get_xoption(config, L"utf8");
+    if (xopt) {
+        wchar_t *sep = wcschr(xopt, L'=');
+        if (sep) {
+            xopt = sep + 1;
+            if (wcscmp(xopt, L"1") == 0) {
+                config->utf8_mode = 1;
+            }
+            else if (wcscmp(xopt, L"0") == 0) {
+                config->utf8_mode = 0;
+            }
+            else {
+                return _Py_INIT_USER_ERR("invalid -X utf8 option value");
+            }
+        }
+        else {
+            config->utf8_mode = 1;
+        }
+        return _Py_INIT_OK();
+    }
+
+    const char *opt = _PyCoreConfig_GetEnv(config, "PYTHONUTF8");
+    if (opt) {
+        if (strcmp(opt, "1") == 0) {
+            config->utf8_mode = 1;
+        }
+        else if (strcmp(opt, "0") == 0) {
+            config->utf8_mode = 0;
+        }
+        else {
+            return _Py_INIT_USER_ERR("invalid PYTHONUTF8 environment "
+                                     "variable value");
+        }
+        return _Py_INIT_OK();
+    }
+
+    return _Py_INIT_OK();
+}
+
+
+static int
+config_str_to_int(const char *str, int *result)
+{
+    const char *endptr = str;
+    errno = 0;
+    long value = strtol(str, (char **)&endptr, 10);
+    if (*endptr != '\0' || errno == ERANGE) {
+        return -1;
+    }
+    if (value < INT_MIN || value > INT_MAX) {
+        return -1;
+    }
+
+    *result = (int)value;
+    return 0;
+}
+
+
+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 void
+get_env_flag(_PyCoreConfig *config, int *flag, const char *name)
+{
+    const char *var = _PyCoreConfig_GetEnv(config, name);
+    if (!var) {
+        return;
+    }
+    int value;
+    if (config_str_to_int(var, &value) < 0 || value < 0) {
+        /* PYTHONDEBUG=text and PYTHONDEBUG=-2 behave as PYTHONDEBUG=1 */
+        value = 1;
+    }
+    if (*flag < value) {
+        *flag = value;
+    }
+}
+
+
+static _PyInitError
+config_read_env_vars(_PyCoreConfig *config)
+{
+    assert(config->use_environment > 0);
+
+    /* Get environment variables */
+    get_env_flag(config, &config->parser_debug, "PYTHONDEBUG");
+    get_env_flag(config, &config->verbose, "PYTHONVERBOSE");
+    get_env_flag(config, &config->optimization_level, "PYTHONOPTIMIZE");
+    get_env_flag(config, &config->inspect, "PYTHONINSPECT");
+
+    int dont_write_bytecode = 0;
+    get_env_flag(config, &dont_write_bytecode, "PYTHONDONTWRITEBYTECODE");
+    if (dont_write_bytecode) {
+        config->write_bytecode = 0;
+    }
+
+    int no_user_site_directory = 0;
+    get_env_flag(config, &no_user_site_directory, "PYTHONNOUSERSITE");
+    if (no_user_site_directory) {
+        config->user_site_directory = 0;
+    }
+
+    int unbuffered_stdio = 0;
+    get_env_flag(config, &unbuffered_stdio, "PYTHONUNBUFFERED");
+    if (unbuffered_stdio) {
+        config->buffered_stdio = 0;
+    }
+
+#ifdef MS_WINDOWS
+    get_env_flag(config, &config->legacy_windows_fs_encoding,
+                 "PYTHONLEGACYWINDOWSFSENCODING");
+    get_env_flag(config, &config->legacy_windows_stdio,
+                 "PYTHONLEGACYWINDOWSSTDIO");
+#endif
+
+    if (config->allocator == NULL) {
+        config->allocator = _PyCoreConfig_GetEnv(config, "PYTHONMALLOC");
+    }
+
+    if (_PyCoreConfig_GetEnv(config, "PYTHONDUMPREFS")) {
+        config->dump_refs = 1;
+    }
+    if (_PyCoreConfig_GetEnv(config, "PYTHONMALLOCSTATS")) {
+        config->malloc_stats = 1;
+    }
+
+    const char *env = _PyCoreConfig_GetEnv(config, "PYTHONCOERCECLOCALE");
+    if (env) {
+        if (strcmp(env, "0") == 0) {
+            config->coerce_c_locale = 0;
+        }
+        else if (strcmp(env, "warn") == 0) {
+            config->coerce_c_locale_warn = 1;
+        }
+        else {
+            config->coerce_c_locale = 1;
+        }
+    }
+
+    wchar_t *path;
+    int res = _PyCoreConfig_GetEnvDup(config, &path,
+                                      L"PYTHONPATH", "PYTHONPATH");
+    if (res < 0) {
+        return DECODE_LOCALE_ERR("PYTHONPATH", res);
+    }
+    config->module_search_path_env = path;
+
+    if (config->use_hash_seed < 0) {
+        _PyInitError err = config_init_hash_seed(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_tracemalloc(_PyCoreConfig *config)
+{
+    int nframe;
+    int valid;
+
+    const char *env = _PyCoreConfig_GetEnv(config, "PYTHONTRACEMALLOC");
+    if (env) {
+        if (!config_str_to_int(env, &nframe)) {
+            valid = (nframe >= 0);
+        }
+        else {
+            valid = 0;
+        }
+        if (!valid) {
+            return _Py_INIT_USER_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 _Py_INIT_USER_ERR("-X tracemalloc=NFRAME: "
+                                         "invalid number of frames");
+            }
+        }
+        else {
+            /* -X tracemalloc behaves as -X tracemalloc=1 */
+            nframe = 1;
+        }
+        config->tracemalloc = nframe;
+    }
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_pycache_prefix(_PyCoreConfig *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 _Py_INIT_NO_MEMORY();
+            }
+        }
+        else {
+            // -X pycache_prefix= can cancel the env var
+            config->pycache_prefix = NULL;
+        }
+    }
+    else {
+        wchar_t *env;
+        int res = _PyCoreConfig_GetEnvDup(config, &env,
+                                          L"PYTHONPYCACHEPREFIX",
+                                          "PYTHONPYCACHEPREFIX");
+        if (res < 0) {
+            return DECODE_LOCALE_ERR("PYTHONPYCACHEPREFIX", res);
+        }
+
+        if (env) {
+            config->pycache_prefix = env;
+        }
+    }
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_read_complex_options(_PyCoreConfig *config)
+{
+    /* More complex options configured by env var and -X option */
+    if (config->faulthandler < 0) {
+        if (_PyCoreConfig_GetEnv(config, "PYTHONFAULTHANDLER")
+           || config_get_xoption(config, L"faulthandler")) {
+            config->faulthandler = 1;
+        }
+    }
+    if (_PyCoreConfig_GetEnv(config, "PYTHONPROFILEIMPORTTIME")
+       || config_get_xoption(config, L"importtime")) {
+        config->import_time = 1;
+    }
+    if (config_get_xoption(config, L"dev" ) ||
+        _PyCoreConfig_GetEnv(config, "PYTHONDEVMODE"))
+    {
+        config->dev_mode = 1;
+    }
+
+    _PyInitError err;
+    if (config->tracemalloc < 0) {
+        err = config_init_tracemalloc(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    if (config->pycache_prefix == NULL) {
+        err = config_init_pycache_prefix(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+    return _Py_INIT_OK();
+}
+
+
+static void
+config_init_locale(_PyCoreConfig *config)
+{
+    if (config->utf8_mode >= 0 && config->coerce_c_locale >= 0) {
+        return;
+    }
+
+    if (_Py_LegacyLocaleDetected()) {
+        /* POSIX locale: enable C locale coercion and UTF-8 Mode */
+        if (config->utf8_mode < 0) {
+            config->utf8_mode = 1;
+        }
+        if (config->coerce_c_locale < 0) {
+            config->coerce_c_locale = 1;
+        }
+        return;
+    }
+}
+
+
+/* Read configuration settings from standard locations
+ *
+ * This function doesn't make any changes to the interpreter state - it
+ * merely populates any missing configuration settings. This allows an
+ * embedding application to completely override a config option by
+ * setting it before calling this function, or else modify the default
+ * setting before passing the fully populated config to Py_EndInitialization.
+ *
+ * More advanced selective initialization tricks are possible by calling
+ * this function multiple times with various preconfigured settings.
+ */
+
+_PyInitError
+_PyCoreConfig_Read(_PyCoreConfig *config)
+{
+    _PyInitError err;
+
+    _PyCoreConfig_GetGlobalConfig(config);
+
+    if (config->isolated > 0) {
+        config->use_environment = 0;
+        config->user_site_directory = 0;
+    }
+
+#ifdef MS_WINDOWS
+    if (config->legacy_windows_fs_encoding) {
+        config->utf8_mode = 0;
+    }
+#endif
+
+    assert(config->use_environment >= 0);
+    if (config->use_environment) {
+        err = config_read_env_vars(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    /* -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;
+    }
+
+    err = config_read_complex_options(config);
+    if (_Py_INIT_FAILED(err)) {
+        return err;
+    }
+
+    if (config->utf8_mode < 0) {
+        err = config_init_utf8_mode(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    if (config->home == NULL) {
+        err = config_init_home(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    if (config->program_name == NULL) {
+        err = config_init_program_name(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    config_init_locale(config);
+
+    if (config->_install_importlib) {
+        err = _PyCoreConfig_InitPathConfig(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    /* default values */
+    if (config->dev_mode) {
+        if (config->faulthandler < 0) {
+            config->faulthandler = 1;
+        }
+        if (config->allocator == NULL) {
+            config->allocator = "debug";
+        }
+    }
+    if (config->use_hash_seed < 0) {
+        config->use_hash_seed = 0;
+        config->hash_seed = 0;
+    }
+    if (config->faulthandler < 0) {
+        config->faulthandler = 0;
+    }
+    if (config->tracemalloc < 0) {
+        config->tracemalloc = 0;
+    }
+    if (config->coerce_c_locale < 0) {
+        config->coerce_c_locale = 0;
+    }
+    if (config->utf8_mode < 0) {
+        config->utf8_mode = 0;
+    }
+    if (config->_frozen < 0) {
+        config->_frozen = 0;
+    }
+    if (config->argc < 0) {
+        config->argc = 0;
+    }
+
+    return _Py_INIT_OK();
+}
diff --git a/Python/import.c b/Python/import.c
index 3a59183..de132a3 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -2279,8 +2279,6 @@ static struct PyModuleDef impmodule = {
     NULL
 };
 
-const char *_Py_CheckHashBasedPycsMode = "default";
-
 PyMODINIT_FUNC
 PyInit__imp(void)
 {
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 63f461a..95fb861 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -108,28 +108,6 @@ _Py_IsFinalizing(void)
     return _PyRuntime.finalizing != NULL;
 }
 
-/* Global configuration variable declarations are in pydebug.h */
-/* XXX (ncoghlan): move those declarations to pylifecycle.h? */
-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
-
 /* Hack to force loading of object files */
 int (*_PyOS_mystrnicmp_hack)(const char *, const char *, Py_ssize_t) = \
     PyOS_mystrnicmp; /* Python/pystrcmp.o */