bpo-32030: Cleanup "path config" code (#4663)

* Rename PyPathConfig structure to _PyPathConfig and move it to
  Include/internal/pystate.h
* Rename path_config to _Py_path_config
* _PyPathConfig: Rename program_name field to program_full_path
* Add assert(str != NULL); to _PyMem_RawWcsdup(), _PyMem_RawStrdup()
  and _PyMem_Strdup().
* Rename calculate_path() to pathconfig_global_init(). The function
  now does nothing if it's already initiallized.

4 files changed, 136 insertions, 137 deletions

diff --git a/Include/internal/pystate.h b/Include/internal/pystate.h
index 7056e10..50ad2fc 100644
--- a/Include/internal/pystate.h
+++ b/Include/internal/pystate.h
@@ -37,6 +37,22 @@ struct _gilstate_runtime_state {
 #define _PyGILState_check_enabled _PyRuntime.gilstate.check_enabled
 
 
+typedef struct {
+    /* Full path to the Python program */
+    wchar_t *program_full_path;
+    wchar_t *prefix;
+#ifdef MS_WINDOWS
+    wchar_t *dll_path;
+#else
+    wchar_t *exec_prefix;
+#endif
+    /* Set by Py_SetPath(), or computed by _PyPathConfig_Init() */
+    wchar_t *module_search_path;
+} _PyPathConfig;
+
+#define _PyPathConfig_INIT {.module_search_path = NULL}
+
+
 /* Full Python runtime state */
 
 typedef struct pyruntimestate {
diff --git a/Modules/getpath.c b/Modules/getpath.c
index 02d626c..9f5e8b3 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -1,6 +1,7 @@
 /* Return the initial module search path. */
 
 #include "Python.h"
+#include "internal/pystate.h"
 #include "osdefs.h"
 
 #include <sys/types.h>
@@ -114,14 +115,6 @@ extern "C" {
      ? _Py_INIT_USER_ERR("cannot decode " #NAME) \
      : _Py_INIT_NO_MEMORY()
 
-
-typedef struct {
-    wchar_t *prefix;
-    wchar_t *exec_prefix;
-    wchar_t *program_name;
-    wchar_t *module_search_path;
-} PyPathConfig;
-
 typedef struct {
     wchar_t *path_env;                 /* PATH environment variable */
     wchar_t *home;                     /* PYTHONHOME environment variable */
@@ -142,7 +135,7 @@ typedef struct {
 
 static const wchar_t delimiter[2] = {DELIM, '\0'};
 static const wchar_t separator[2] = {SEP, '\0'};
-static PyPathConfig path_config = {.module_search_path = NULL};
+static _PyPathConfig _Py_path_config = _PyPathConfig_INIT;
 
 
 /* Get file status. Encode the path to the locale encoding. */
@@ -592,10 +585,10 @@ calculate_reduce_exec_prefix(PyCalculatePath *calculate, wchar_t *exec_prefix)
 
 
 static _PyInitError
-calculate_program_name(PyCalculatePath *calculate, PyPathConfig *config)
+calculate_program_full_path(PyCalculatePath *calculate, _PyPathConfig *config)
 {
-    wchar_t program_name[MAXPATHLEN+1];
-    memset(program_name, 0, sizeof(program_name));
+    wchar_t program_full_path[MAXPATHLEN+1];
+    memset(program_full_path, 0, sizeof(program_full_path));
 
 #ifdef __APPLE__
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_4
@@ -612,7 +605,7 @@ calculate_program_name(PyCalculatePath *calculate, PyPathConfig *config)
      * $PATH isn't exported, you lose.
      */
     if (wcschr(calculate->program_name, SEP)) {
-        wcsncpy(program_name, calculate->program_name, MAXPATHLEN);
+        wcsncpy(program_full_path, calculate->program_name, MAXPATHLEN);
     }
 #ifdef __APPLE__
      /* On Mac OS X, if a script uses an interpreter of the form
@@ -628,10 +621,10 @@ calculate_program_name(PyCalculatePath *calculate, PyPathConfig *config)
     else if(0 == _NSGetExecutablePath(execpath, &nsexeclength) &&
             execpath[0] == SEP)
     {
-        size_t r = mbstowcs(program_name, execpath, MAXPATHLEN+1);
+        size_t r = mbstowcs(program_full_path, execpath, MAXPATHLEN+1);
         if (r == (size_t)-1 || r > MAXPATHLEN) {
             /* Could not convert execpath, or it's too long. */
-            program_name[0] = '\0';
+            program_full_path[0] = '\0';
         }
     }
 #endif /* __APPLE__ */
@@ -645,34 +638,34 @@ calculate_program_name(PyCalculatePath *calculate, PyPathConfig *config)
                 if (len > MAXPATHLEN) {
                     len = MAXPATHLEN;
                 }
-                wcsncpy(program_name, path, len);
-                program_name[len] = '\0';
+                wcsncpy(program_full_path, path, len);
+                program_full_path[len] = '\0';
             }
             else {
-                wcsncpy(program_name, path, MAXPATHLEN);
+                wcsncpy(program_full_path, path, MAXPATHLEN);
             }
 
-            joinpath(program_name, calculate->program_name);
-            if (isxfile(program_name)) {
+            joinpath(program_full_path, calculate->program_name);
+            if (isxfile(program_full_path)) {
                 break;
             }
 
             if (!delim) {
-                program_name[0] = L'\0';
+                program_full_path[0] = L'\0';
                 break;
             }
             path = delim + 1;
         }
     }
     else {
-        program_name[0] = '\0';
+        program_full_path[0] = '\0';
     }
-    if (program_name[0] != SEP && program_name[0] != '\0') {
-        absolutize(program_name);
+    if (program_full_path[0] != SEP && program_full_path[0] != '\0') {
+        absolutize(program_full_path);
     }
 
-    config->program_name = _PyMem_RawWcsdup(program_name);
-    if (config->program_name == NULL) {
+    config->program_full_path = _PyMem_RawWcsdup(program_full_path);
+    if (config->program_full_path == NULL) {
         return _Py_INIT_NO_MEMORY();
     }
     return _Py_INIT_OK();
@@ -680,9 +673,9 @@ calculate_program_name(PyCalculatePath *calculate, PyPathConfig *config)
 
 
 static _PyInitError
-calculate_argv0_path(PyCalculatePath *calculate, const wchar_t *program_name)
+calculate_argv0_path(PyCalculatePath *calculate, const wchar_t *program_full_path)
 {
-    wcsncpy(calculate->argv0_path, program_name, MAXPATHLEN);
+    wcsncpy(calculate->argv0_path, program_full_path, MAXPATHLEN);
     calculate->argv0_path[MAXPATHLEN] = '\0';
 
 #ifdef WITH_NEXT_FRAMEWORK
@@ -718,10 +711,10 @@ calculate_argv0_path(PyCalculatePath *calculate, const wchar_t *program_name)
         if (!ismodule(calculate->argv0_path)) {
             /* We are in the build directory so use the name of the
                executable - we know that the absolute path is passed */
-            wcsncpy(calculate->argv0_path, program_name, MAXPATHLEN);
+            wcsncpy(calculate->argv0_path, program_full_path, MAXPATHLEN);
         }
         else {
-            /* Use the location of the library as the program_name */
+            /* Use the location of the library as the program_full_path */
             wcsncpy(calculate->argv0_path, wbuf, MAXPATHLEN);
         }
         PyMem_RawFree(wbuf);
@@ -730,7 +723,7 @@ calculate_argv0_path(PyCalculatePath *calculate, const wchar_t *program_name)
 
 #if HAVE_READLINK
     wchar_t tmpbuffer[MAXPATHLEN+1];
-    int linklen = _Py_wreadlink(program_name, tmpbuffer, MAXPATHLEN);
+    int linklen = _Py_wreadlink(program_full_path, tmpbuffer, MAXPATHLEN);
     while (linklen != -1) {
         if (tmpbuffer[0] == SEP) {
             /* tmpbuffer should never be longer than MAXPATHLEN,
@@ -738,7 +731,7 @@ calculate_argv0_path(PyCalculatePath *calculate, const wchar_t *program_name)
             wcsncpy(calculate->argv0_path, tmpbuffer, MAXPATHLEN);
         }
         else {
-            /* Interpret relative to program_name */
+            /* Interpret relative to program_full_path */
             reduce(calculate->argv0_path);
             joinpath(calculate->argv0_path, tmpbuffer);
         }
@@ -819,7 +812,7 @@ calculate_zip_path(PyCalculatePath *calculate, const wchar_t *prefix)
 static _PyInitError
 calculate_module_search_path(PyCalculatePath *calculate,
                              const wchar_t *prefix, const wchar_t *exec_prefix,
-                             PyPathConfig *config)
+                             _PyPathConfig *config)
 {
     /* Calculate size of return buffer */
     size_t bufsz = 0;
@@ -955,14 +948,14 @@ calculate_free(PyCalculatePath *calculate)
 
 
 static _PyInitError
-calculate_path_impl(PyCalculatePath *calculate, PyPathConfig *config)
+calculate_path_impl(PyCalculatePath *calculate, _PyPathConfig *config)
 {
-    _PyInitError err = calculate_program_name(calculate, config);
+    _PyInitError err = calculate_program_full_path(calculate, config);
     if (_Py_INIT_FAILED(err)) {
         return err;
     }
 
-    err = calculate_argv0_path(calculate, config->program_name);
+    err = calculate_argv0_path(calculate, config->program_full_path);
     if (_Py_INIT_FAILED(err)) {
         return err;
     }
@@ -1011,7 +1004,7 @@ calculate_path_impl(PyCalculatePath *calculate, PyPathConfig *config)
 
 
 static void
-pathconfig_clear(PyPathConfig *config)
+pathconfig_clear(_PyPathConfig *config)
 {
 #define CLEAR(ATTR) \
     do { \
@@ -1021,7 +1014,7 @@ pathconfig_clear(PyPathConfig *config)
 
     CLEAR(config->prefix);
     CLEAR(config->exec_prefix);
-    CLEAR(config->program_name);
+    CLEAR(config->program_full_path);
     CLEAR(config->module_search_path);
 #undef CLEAR
 }
@@ -1032,7 +1025,7 @@ pathconfig_clear(PyPathConfig *config)
 _PyInitError
 _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
 {
-    if (path_config.module_search_path) {
+    if (_Py_path_config.module_search_path) {
         /* Already initialized */
         return _Py_INIT_OK();
     }
@@ -1045,7 +1038,7 @@ _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
         goto done;
     }
 
-    PyPathConfig new_path_config;
+    _PyPathConfig new_path_config;
     memset(&new_path_config, 0, sizeof(new_path_config));
 
     err = calculate_path_impl(&calculate, &new_path_config);
@@ -1054,7 +1047,7 @@ _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
         goto done;
     }
 
-    path_config = new_path_config;
+    _Py_path_config = new_path_config;
     err = _Py_INIT_OK();
 
 done:
@@ -1064,8 +1057,13 @@ done:
 
 
 static void
-calculate_path(void)
+pathconfig_global_init(void)
 {
+    if (_Py_path_config.module_search_path) {
+        /* Already initialized */
+        return;
+    }
+
     _PyInitError err;
     _PyMainInterpreterConfig config = _PyMainInterpreterConfig_INIT;
 
@@ -1084,7 +1082,7 @@ calculate_path(void)
 void
 _PyPathConfig_Fini(void)
 {
-    pathconfig_clear(&path_config);
+    pathconfig_clear(&_Py_path_config);
 }
 
 
@@ -1093,58 +1091,50 @@ void
 Py_SetPath(const wchar_t *path)
 {
     if (path == NULL) {
-        pathconfig_clear(&path_config);
+        pathconfig_clear(&_Py_path_config);
         return;
     }
 
-    PyPathConfig new_config;
-    new_config.program_name = _PyMem_RawWcsdup(Py_GetProgramName());
+    _PyPathConfig new_config;
+    new_config.program_full_path = _PyMem_RawWcsdup(Py_GetProgramName());
     new_config.exec_prefix = _PyMem_RawWcsdup(L"");
     new_config.prefix = _PyMem_RawWcsdup(L"");
     new_config.module_search_path = _PyMem_RawWcsdup(path);
 
-    pathconfig_clear(&path_config);
-    path_config = new_config;
+    pathconfig_clear(&_Py_path_config);
+    _Py_path_config = new_config;
 }
 
 
 wchar_t *
 Py_GetPath(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.module_search_path;
+    pathconfig_global_init();
+    return _Py_path_config.module_search_path;
 }
 
 
 wchar_t *
 Py_GetPrefix(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.prefix;
+    pathconfig_global_init();
+    return _Py_path_config.prefix;
 }
 
 
 wchar_t *
 Py_GetExecPrefix(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.exec_prefix;
+    pathconfig_global_init();
+    return _Py_path_config.exec_prefix;
 }
 
 
 wchar_t *
 Py_GetProgramFullPath(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.program_name;
+    pathconfig_global_init();
+    return _Py_path_config.program_full_path;
 }
 
 #ifdef __cplusplus
diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
index 4d85f0c..7911028 100644
--- a/Objects/obmalloc.c
+++ b/Objects/obmalloc.c
@@ -564,6 +564,8 @@ PyMem_Free(void *ptr)
 wchar_t*
 _PyMem_RawWcsdup(const wchar_t *str)
 {
+    assert(str != NULL);
+
     size_t len = wcslen(str);
     if (len > (size_t)PY_SSIZE_T_MAX / sizeof(wchar_t) - 1) {
         return NULL;
@@ -582,13 +584,12 @@ _PyMem_RawWcsdup(const wchar_t *str)
 char *
 _PyMem_RawStrdup(const char *str)
 {
-    size_t size;
-    char *copy;
-
-    size = strlen(str) + 1;
-    copy = PyMem_RawMalloc(size);
-    if (copy == NULL)
+    assert(str != NULL);
+    size_t size = strlen(str) + 1;
+    char *copy = PyMem_RawMalloc(size);
+    if (copy == NULL) {
         return NULL;
+    }
     memcpy(copy, str, size);
     return copy;
 }
@@ -596,13 +597,12 @@ _PyMem_RawStrdup(const char *str)
 char *
 _PyMem_Strdup(const char *str)
 {
-    size_t size;
-    char *copy;
-
-    size = strlen(str) + 1;
-    copy = PyMem_Malloc(size);
-    if (copy == NULL)
+    assert(str != NULL);
+    size_t size = strlen(str) + 1;
+    char *copy = PyMem_Malloc(size);
+    if (copy == NULL) {
         return NULL;
+    }
     memcpy(copy, str, size);
     return copy;
 }
diff --git a/PC/getpathp.c b/PC/getpathp.c
index fe0226b..ad04b6b 100644
--- a/PC/getpathp.c
+++ b/PC/getpathp.c
@@ -80,6 +80,7 @@
 
 
 #include "Python.h"
+#include "internal/pystate.h"
 #include "osdefs.h"
 #include <wchar.h>
 
@@ -117,13 +118,6 @@
 #endif
 
 typedef struct {
-    wchar_t *prefix;
-    wchar_t *program_name;
-    wchar_t *dll_path;
-    wchar_t *module_search_path;
-} PyPathConfig;
-
-typedef struct {
     wchar_t *module_search_path_env;   /* PYTHONPATH environment variable */
     wchar_t *path_env;                 /* PATH environment variable */
     wchar_t *home;                     /* PYTHONHOME environment variable */
@@ -138,7 +132,7 @@ typedef struct {
 } PyCalculatePath;
 
 
-static PyPathConfig path_config = {.module_search_path = NULL};
+static _PyPathConfig _Py_path_config = _PyPathConfig_INIT;
 
 
 /* determine if "ch" is a separator character */
@@ -295,7 +289,7 @@ gotlandmark(wchar_t *prefix, const wchar_t *landmark)
 
 
 /* assumes argv0_path is MAXPATHLEN+1 bytes long, already \0 term'd.
-   assumption provided by only caller, calculate_path() */
+   assumption provided by only caller, calculate_path_impl() */
 static int
 search_for_prefix(wchar_t *prefix, wchar_t *argv0_path, const wchar_t *landmark)
 {
@@ -484,7 +478,7 @@ done:
 
 
 static _PyInitError
-get_dll_path(PyCalculatePath *calculate, PyPathConfig *config)
+get_dll_path(PyCalculatePath *calculate, _PyPathConfig *config)
 {
     wchar_t dll_path[MAXPATHLEN+1];
     memset(dll_path, 0, sizeof(dll_path));
@@ -509,12 +503,12 @@ get_dll_path(PyCalculatePath *calculate, PyPathConfig *config)
 
 
 static _PyInitError
-get_program_name(PyCalculatePath *calculate, PyPathConfig *config)
+get_program_full_path(PyCalculatePath *calculate, _PyPathConfig *config)
 {
-    wchar_t program_name[MAXPATHLEN+1];
-    memset(program_name, 0, sizeof(program_name));
+    wchar_t program_full_path[MAXPATHLEN+1];
+    memset(program_full_path, 0, sizeof(program_full_path));
 
-    if (GetModuleFileNameW(NULL, program_name, MAXPATHLEN)) {
+    if (GetModuleFileNameW(NULL, program_full_path, MAXPATHLEN)) {
         goto done;
     }
 
@@ -529,7 +523,7 @@ get_program_name(PyCalculatePath *calculate, PyPathConfig *config)
     if (wcschr(calculate->program_name, SEP))
 #endif
     {
-        wcsncpy(program_name, calculate->program_name, MAXPATHLEN);
+        wcsncpy(program_full_path, calculate->program_name, MAXPATHLEN);
     }
     else if (calculate->path_env) {
         wchar_t *path = calculate->path_env;
@@ -540,33 +534,33 @@ get_program_name(PyCalculatePath *calculate, PyPathConfig *config)
                 size_t len = delim - path;
                 /* ensure we can't overwrite buffer */
                 len = min(MAXPATHLEN,len);
-                wcsncpy(program_name, path, len);
-                program_name[len] = '\0';
+                wcsncpy(program_full_path, path, len);
+                program_full_path[len] = '\0';
             }
             else {
-                wcsncpy(program_name, path, MAXPATHLEN);
+                wcsncpy(program_full_path, path, MAXPATHLEN);
             }
 
             /* join() is safe for MAXPATHLEN+1 size buffer */
-            join(program_name, calculate->program_name);
-            if (exists(program_name)) {
+            join(program_full_path, calculate->program_name);
+            if (exists(program_full_path)) {
                 break;
             }
 
             if (!delim) {
-                program_name[0] = '\0';
+                program_full_path[0] = '\0';
                 break;
             }
             path = delim + 1;
         }
     }
     else {
-        program_name[0] = '\0';
+        program_full_path[0] = '\0';
     }
 
 done:
-    config->program_name = _PyMem_RawWcsdup(program_name);
-    if (config->program_name == NULL) {
+    config->program_full_path = _PyMem_RawWcsdup(program_full_path);
+    if (config->program_full_path == NULL) {
         return _Py_INIT_NO_MEMORY();
     }
     return _Py_INIT_OK();
@@ -626,7 +620,7 @@ find_env_config_value(FILE * env_file, const wchar_t * key, wchar_t * value)
 
 
 static int
-read_pth_file(PyPathConfig *config, wchar_t *prefix, const wchar_t *path,
+read_pth_file(_PyPathConfig *config, wchar_t *prefix, const wchar_t *path,
               int *isolated, int *nosite)
 {
     FILE *sp_file = _Py_wfopen(path, L"r");
@@ -727,15 +721,15 @@ calculate_init(PyCalculatePath *calculate,
 
 
 static int
-get_pth_filename(wchar_t *spbuffer, PyPathConfig *config)
+get_pth_filename(wchar_t *spbuffer, _PyPathConfig *config)
 {
     if (config->dll_path[0]) {
         if (!change_ext(spbuffer, config->dll_path, L"._pth") && exists(spbuffer)) {
             return 1;
         }
     }
-    if (config->program_name[0]) {
-        if (!change_ext(spbuffer, config->program_name, L"._pth") && exists(spbuffer)) {
+    if (config->program_full_path[0]) {
+        if (!change_ext(spbuffer, config->program_full_path, L"._pth") && exists(spbuffer)) {
             return 1;
         }
     }
@@ -744,7 +738,7 @@ get_pth_filename(wchar_t *spbuffer, PyPathConfig *config)
 
 
 static int
-calculate_pth_file(PyPathConfig *config, wchar_t *prefix)
+calculate_pth_file(_PyPathConfig *config, wchar_t *prefix)
 {
     wchar_t spbuffer[MAXPATHLEN+1];
 
@@ -821,7 +815,7 @@ calculate_home_prefix(PyCalculatePath *calculate, wchar_t *prefix)
 
 
 static _PyInitError
-calculate_module_search_path(PyCalculatePath *calculate, PyPathConfig *config, wchar_t *prefix)
+calculate_module_search_path(PyCalculatePath *calculate, _PyPathConfig *config, wchar_t *prefix)
 {
     int skiphome = calculate->home==NULL ? 0 : 1;
 #ifdef Py_ENABLE_SHARED
@@ -1002,7 +996,7 @@ calculate_module_search_path(PyCalculatePath *calculate, PyPathConfig *config, w
 
 
 static _PyInitError
-calculate_path_impl(PyCalculatePath *calculate, PyPathConfig *config,
+calculate_path_impl(PyCalculatePath *calculate, _PyPathConfig *config,
                     const _PyMainInterpreterConfig *main_config)
 {
     _PyInitError err;
@@ -1012,13 +1006,13 @@ calculate_path_impl(PyCalculatePath *calculate, PyPathConfig *config,
         return err;
     }
 
-    err = get_program_name(calculate, config);
+    err = get_program_full_path(calculate, config);
     if (_Py_INIT_FAILED(err)) {
         return err;
     }
 
-    /* program_name guaranteed \0 terminated in MAXPATH+1 bytes. */
-    wcscpy_s(calculate->argv0_path, MAXPATHLEN+1, config->program_name);
+    /* program_full_path guaranteed \0 terminated in MAXPATH+1 bytes. */
+    wcscpy_s(calculate->argv0_path, MAXPATHLEN+1, config->program_full_path);
     reduce(calculate->argv0_path);
 
     wchar_t prefix[MAXPATHLEN+1];
@@ -1033,7 +1027,7 @@ calculate_path_impl(PyCalculatePath *calculate, PyPathConfig *config,
 
     /* Calculate zip archive path from DLL or exe path */
     change_ext(calculate->zip_path,
-               config->dll_path[0] ? config->dll_path : config->program_name,
+               config->dll_path[0] ? config->dll_path : config->program_full_path,
                L".zip");
 
     calculate_home_prefix(calculate, prefix);
@@ -1062,7 +1056,7 @@ calculate_free(PyCalculatePath *calculate)
 
 
 static void
-pathconfig_clear(PyPathConfig *config)
+pathconfig_clear(_PyPathConfig *config)
 {
 #define CLEAR(ATTR) \
     do { \
@@ -1071,7 +1065,7 @@ pathconfig_clear(PyPathConfig *config)
     } while (0)
 
     CLEAR(config->prefix);
-    CLEAR(config->program_name);
+    CLEAR(config->program_full_path);
     CLEAR(config->dll_path);
     CLEAR(config->module_search_path);
 #undef CLEAR
@@ -1083,7 +1077,7 @@ pathconfig_clear(PyPathConfig *config)
 _PyInitError
 _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
 {
-    if (path_config.module_search_path) {
+    if (_Py_path_config.module_search_path) {
         /* Already initialized */
         return _Py_INIT_OK();
     }
@@ -1095,7 +1089,7 @@ _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
 
     calculate_init(&calculate, main_config);
 
-    PyPathConfig new_path_config;
+    _PyPathConfig new_path_config;
     memset(&new_path_config, 0, sizeof(new_path_config));
 
     err = calculate_path_impl(&calculate, &new_path_config, main_config);
@@ -1103,7 +1097,7 @@ _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
         goto done;
     }
 
-    path_config = new_path_config;
+    _Py_path_config = new_path_config;
     err = _Py_INIT_OK();
 
 done:
@@ -1116,8 +1110,13 @@ done:
 
 
 static void
-calculate_path(void)
+pathconfig_global_init(void)
 {
+    if (_Py_path_config.module_search_path) {
+        /* Already initialized */
+        return;
+    }
+
     _PyInitError err;
     _PyMainInterpreterConfig config = _PyMainInterpreterConfig_INIT;
 
@@ -1136,7 +1135,7 @@ calculate_path(void)
 void
 _PyPathConfig_Fini(void)
 {
-    pathconfig_clear(&path_config);
+    pathconfig_clear(&_Py_path_config);
 }
 
 
@@ -1145,42 +1144,38 @@ _PyPathConfig_Fini(void)
 void
 Py_SetPath(const wchar_t *path)
 {
-    if (path_config.module_search_path != NULL) {
-        pathconfig_clear(&path_config);
+    if (_Py_path_config.module_search_path != NULL) {
+        pathconfig_clear(&_Py_path_config);
     }
 
     if (path == NULL) {
         return;
     }
 
-    PyPathConfig new_config;
-    new_config.program_name = _PyMem_RawWcsdup(Py_GetProgramName());
+    _PyPathConfig new_config;
+    new_config.program_full_path = _PyMem_RawWcsdup(Py_GetProgramName());
     new_config.prefix = _PyMem_RawWcsdup(L"");
     new_config.dll_path = _PyMem_RawWcsdup(L"");
     new_config.module_search_path = _PyMem_RawWcsdup(path);
 
-    pathconfig_clear(&path_config);
-    path_config = new_config;
+    pathconfig_clear(&_Py_path_config);
+    _Py_path_config = new_config;
 }
 
 
 wchar_t *
 Py_GetPath(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.module_search_path;
+    pathconfig_global_init();
+    return _Py_path_config.module_search_path;
 }
 
 
 wchar_t *
 Py_GetPrefix(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.prefix;
+    pathconfig_global_init();
+    return _Py_path_config.prefix;
 }
 
 
@@ -1194,10 +1189,8 @@ Py_GetExecPrefix(void)
 wchar_t *
 Py_GetProgramFullPath(void)
 {
-    if (!path_config.module_search_path) {
-        calculate_path();
-    }
-    return path_config.program_name;
+    pathconfig_global_init();
+    return _Py_path_config.program_full_path;
 }
 
 
@@ -1221,7 +1214,7 @@ _Py_CheckPython3()
 
     /* If there is a python3.dll next to the python3y.dll,
        assume this is a build tree; use that DLL */
-    wcscpy(py3path, path_config.dll_path);
+    wcscpy(py3path, _Py_path_config.dll_path);
     s = wcsrchr(py3path, L'\\');
     if (!s) {
         s = py3path;