Revert "bpo-32197: Try to fix a compiler error on OS X introduced in bpo-32030. (#4681)" (#4694)

* Revert "bpo-32197: Try to fix a compiler error on OS X introduced in bpo-32030. (#4681)"

This reverts commit 13badcbc60cdbfae1dba1683fd2fae9d70717143.

Re-apply commits:

* "bpo-32030: _PyPathConfig_Init() sets home and program_name (#4673)"
  commit af5a895073c24637c094772b27526b94a12ec897.
* "bpo-32030: Fix config_get_program_name() on macOS (#4669)"
  commit e23c06e2b03452c9aaf0dae52296c85e572f9bcd.
* "bpo-32030: Add Python/pathconfig.c (#4668)"
  commit 0ea395ae964c9cd0f499e2ef0d0030c971201220.
* "bpo-32030: Don't call _PyPathConfig_Fini() in Py_FinalizeEx() (#4667)"
  commit ebac19dad6263141d5db0a2c923efe049dba99d2.
* "bpo-32030: Fix Py_GetPath(): init program_name (#4665)"
  commit 9ac3d8882712c9675c3d2f9f84af6b5729575cde.

* Fix compilation error on macOS

2 files changed, 272 insertions, 58 deletions

diff --git a/Python/pathconfig.c b/Python/pathconfig.c
new file mode 100644
index 0000000..6a03f7d
--- /dev/null
+++ b/Python/pathconfig.c
@@ -0,0 +1,266 @@
+/* Path configuration like module_search_path (sys.path) */
+
+#include "Python.h"
+#include "osdefs.h"
+#include "internal/pystate.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+_PyPathConfig _Py_path_config = _PyPathConfig_INIT;
+
+
+void
+_PyPathConfig_Clear(_PyPathConfig *config)
+{
+    /* _PyMem_SetDefaultAllocator() is needed to get a known memory allocator,
+       since Py_SetPath(), Py_SetPythonHome() and Py_SetProgramName() can be
+       called before Py_Initialize() which can changes the memory allocator. */
+    PyMemAllocatorEx old_alloc;
+    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+#define CLEAR(ATTR) \
+    do { \
+        PyMem_RawFree(ATTR); \
+        ATTR = NULL; \
+    } while (0)
+
+    CLEAR(config->prefix);
+    CLEAR(config->program_full_path);
+#ifdef MS_WINDOWS
+    CLEAR(config->dll_path);
+#else
+    CLEAR(config->exec_prefix);
+#endif
+    CLEAR(config->module_search_path);
+    CLEAR(config->home);
+    CLEAR(config->program_name);
+#undef CLEAR
+
+    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+}
+
+
+/* Initialize paths for Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix()
+   and Py_GetProgramFullPath() */
+_PyInitError
+_PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
+{
+    if (_Py_path_config.module_search_path) {
+        /* Already initialized */
+        return _Py_INIT_OK();
+    }
+
+    _PyInitError err;
+    _PyPathConfig new_config = _PyPathConfig_INIT;
+
+    PyMemAllocatorEx old_alloc;
+    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+    /* Calculate program_full_path, prefix, exec_prefix (Unix)
+       or dll_path (Windows), and module_search_path */
+    err = _PyPathConfig_Calculate(&new_config, main_config);
+    if (_Py_INIT_FAILED(err)) {
+        _PyPathConfig_Clear(&new_config);
+        goto done;
+    }
+
+    /* Copy home and program_name from main_config */
+    if (main_config->home != NULL) {
+        new_config.home = _PyMem_RawWcsdup(main_config->home);
+        if (new_config.home == NULL) {
+            err = _Py_INIT_NO_MEMORY();
+            goto done;
+        }
+    }
+    else {
+        new_config.home = NULL;
+    }
+
+    new_config.program_name = _PyMem_RawWcsdup(main_config->program_name);
+    if (new_config.program_name == NULL) {
+        err = _Py_INIT_NO_MEMORY();
+        goto done;
+    }
+
+    _PyPathConfig_Clear(&_Py_path_config);
+    _Py_path_config = new_config;
+
+    err = _Py_INIT_OK();
+
+done:
+    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+    return err;
+}
+
+
+static void
+pathconfig_global_init(void)
+{
+    if (_Py_path_config.module_search_path) {
+        /* Already initialized */
+        return;
+    }
+
+    _PyInitError err;
+    _PyMainInterpreterConfig config = _PyMainInterpreterConfig_INIT;
+
+    err = _PyMainInterpreterConfig_ReadEnv(&config);
+    if (_Py_INIT_FAILED(err)) {
+        goto error;
+    }
+
+    err = _PyMainInterpreterConfig_Read(&config);
+    if (_Py_INIT_FAILED(err)) {
+        goto error;
+    }
+
+    err = _PyPathConfig_Init(&config);
+    if (_Py_INIT_FAILED(err)) {
+        goto error;
+    }
+
+    _PyMainInterpreterConfig_Clear(&config);
+    return;
+
+error:
+    _PyMainInterpreterConfig_Clear(&config);
+    _Py_FatalInitError(err);
+}
+
+
+/* External interface */
+
+void
+Py_SetPath(const wchar_t *path)
+{
+    if (path == NULL) {
+        _PyPathConfig_Clear(&_Py_path_config);
+        return;
+    }
+
+    PyMemAllocatorEx old_alloc;
+    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+    _PyPathConfig new_config;
+    new_config.program_full_path = _PyMem_RawWcsdup(Py_GetProgramName());
+    new_config.prefix = _PyMem_RawWcsdup(L"");
+#ifdef MS_WINDOWS
+    new_config.dll_path = _PyMem_RawWcsdup(L"");
+#else
+    new_config.exec_prefix = _PyMem_RawWcsdup(L"");
+#endif
+    new_config.module_search_path = _PyMem_RawWcsdup(path);
+
+    /* steal the home and program_name values (to leave them unchanged) */
+    new_config.home = _Py_path_config.home;
+    _Py_path_config.home = NULL;
+    new_config.program_name = _Py_path_config.program_name;
+    _Py_path_config.program_name = NULL;
+
+    _PyPathConfig_Clear(&_Py_path_config);
+    _Py_path_config = new_config;
+
+    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+}
+
+
+void
+Py_SetPythonHome(wchar_t *home)
+{
+    if (home == NULL) {
+        return;
+    }
+
+    PyMemAllocatorEx old_alloc;
+    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+    PyMem_RawFree(_Py_path_config.home);
+    _Py_path_config.home = _PyMem_RawWcsdup(home);
+
+    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+    if (_Py_path_config.home == NULL) {
+        Py_FatalError("Py_SetPythonHome() failed: out of memory");
+    }
+}
+
+
+void
+Py_SetProgramName(wchar_t *program_name)
+{
+    if (program_name == NULL || program_name[0] == L'\0') {
+        return;
+    }
+
+    PyMemAllocatorEx old_alloc;
+    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+    PyMem_RawFree(_Py_path_config.program_name);
+    _Py_path_config.program_name = _PyMem_RawWcsdup(program_name);
+
+    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+    if (_Py_path_config.program_name == NULL) {
+        Py_FatalError("Py_SetProgramName() failed: out of memory");
+    }
+}
+
+
+wchar_t *
+Py_GetPath(void)
+{
+    pathconfig_global_init();
+    return _Py_path_config.module_search_path;
+}
+
+
+wchar_t *
+Py_GetPrefix(void)
+{
+    pathconfig_global_init();
+    return _Py_path_config.prefix;
+}
+
+
+wchar_t *
+Py_GetExecPrefix(void)
+{
+#ifdef MS_WINDOWS
+    return Py_GetPrefix();
+#else
+    pathconfig_global_init();
+    return _Py_path_config.exec_prefix;
+#endif
+}
+
+
+wchar_t *
+Py_GetProgramFullPath(void)
+{
+    pathconfig_global_init();
+    return _Py_path_config.program_full_path;
+}
+
+
+wchar_t*
+Py_GetPythonHome(void)
+{
+    pathconfig_global_init();
+    return _Py_path_config.home;
+}
+
+
+wchar_t *
+Py_GetProgramName(void)
+{
+    pathconfig_global_init();
+    return _Py_path_config.program_name;
+}
+
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index f0a49f9..523397f 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -804,7 +804,12 @@ _PyMainInterpreterConfig_Read(_PyMainInterpreterConfig *config)
     }
 
     if (config->program_name == NULL) {
-        config->program_name = _PyMem_RawWcsdup(Py_GetProgramName());
+#ifdef MS_WINDOWS
+        const wchar_t *program_name = L"python";
+#else
+        const wchar_t *program_name = L"python3";
+#endif
+        config->program_name = _PyMem_RawWcsdup(program_name);
         if (config->program_name == NULL) {
             return _Py_INIT_NO_MEMORY();
         }
@@ -1273,8 +1278,6 @@ Py_FinalizeEx(void)
 
     call_ll_exitfuncs();
 
-    _PyPathConfig_Fini();
-
     _PyRuntime_Finalize();
     return status;
 }
@@ -1491,61 +1494,6 @@ Py_EndInterpreter(PyThreadState *tstate)
     PyInterpreterState_Delete(interp);
 }
 
-#ifdef MS_WINDOWS
-static wchar_t *progname = L"python";
-#else
-static wchar_t *progname = L"python3";
-#endif
-
-void
-Py_SetProgramName(wchar_t *pn)
-{
-    if (pn && *pn)
-        progname = pn;
-}
-
-wchar_t *
-Py_GetProgramName(void)
-{
-    return progname;
-}
-
-static wchar_t *default_home = NULL;
-
-void
-Py_SetPythonHome(wchar_t *home)
-{
-    default_home = home;
-}
-
-
-wchar_t*
-Py_GetPythonHome(void)
-{
-    /* Use a static buffer to avoid heap memory allocation failure.
-       Py_GetPythonHome() doesn't allow to report error, and the caller
-       doesn't release memory. */
-    static wchar_t buffer[MAXPATHLEN+1];
-
-    if (default_home) {
-        return default_home;
-    }
-
-    char *home = Py_GETENV("PYTHONHOME");
-    if (!home) {
-        return NULL;
-    }
-
-    size_t size = Py_ARRAY_LENGTH(buffer);
-    size_t r = mbstowcs(buffer, home, size);
-    if (r == (size_t)-1 || r >= size) {
-        /* conversion failed or the static buffer is too small */
-        return NULL;
-    }
-
-    return buffer;
-}
-
 /* Add the __main__ module */
 
 static _PyInitError