bpo-32030: Fix Py_GetPath(): init program_name (#4665)

* _PyMainInterpreterConfig_ReadEnv() now sets program_name from
  environment variables and pymain_parse_envvars() implements the
  falls back on argv[0].
* Remove _PyMain.program_name: use the program_name from
  _PyMainInterpreterConfig
* Move the Py_SetProgramName() call back to pymain_init_python(),
  just before _Py_InitializeCore().
* pathconfig_global_init() now also calls
  _PyMainInterpreterConfig_Read() to set program_name if it isn't set
  yet
* Cleanup PyCalculatePath: pass main_config to subfunctions to get
  directly fields from main_config (home, module_search_path_env and
  program_name)

1 files changed, 38 insertions, 27 deletions

diff --git a/PC/getpathp.c b/PC/getpathp.c
index ad04b6b6ef..89d37a8413 100644
--- a/PC/getpathp.c
+++ b/PC/getpathp.c
@@ -118,7 +118,6 @@
 #endif
 
 typedef struct {
-    wchar_t *module_search_path_env;   /* PYTHONPATH environment variable */
     wchar_t *path_env;                 /* PATH environment variable */
     wchar_t *home;                     /* PYTHONHOME environment variable */
 
@@ -126,7 +125,6 @@ typedef struct {
     wchar_t *machine_path;   /* from HKEY_LOCAL_MACHINE */
     wchar_t *user_path;      /* from HKEY_CURRENT_USER */
 
-    wchar_t *program_name;             /* Program name */
     wchar_t argv0_path[MAXPATHLEN+1];
     wchar_t zip_path[MAXPATHLEN+1];
 } PyCalculatePath;
@@ -503,7 +501,8 @@ get_dll_path(PyCalculatePath *calculate, _PyPathConfig *config)
 
 
 static _PyInitError
-get_program_full_path(PyCalculatePath *calculate, _PyPathConfig *config)
+get_program_full_path(const _PyMainInterpreterConfig *main_config,
+                      PyCalculatePath *calculate, _PyPathConfig *config)
 {
     wchar_t program_full_path[MAXPATHLEN+1];
     memset(program_full_path, 0, sizeof(program_full_path));
@@ -518,12 +517,13 @@ get_program_full_path(PyCalculatePath *calculate, _PyPathConfig *config)
      * $PATH isn't exported, you lose.
      */
 #ifdef ALTSEP
-    if (wcschr(calculate->program_name, SEP) || wcschr(calculate->program_name, ALTSEP))
+    if (wcschr(main_config->program_name, SEP) ||
+        wcschr(main_config->program_name, ALTSEP))
 #else
-    if (wcschr(calculate->program_name, SEP))
+    if (wcschr(main_config->program_name, SEP))
 #endif
     {
-        wcsncpy(program_full_path, calculate->program_name, MAXPATHLEN);
+        wcsncpy(program_full_path, main_config->program_name, MAXPATHLEN);
     }
     else if (calculate->path_env) {
         wchar_t *path = calculate->path_env;
@@ -542,7 +542,7 @@ get_program_full_path(PyCalculatePath *calculate, _PyPathConfig *config)
             }
 
             /* join() is safe for MAXPATHLEN+1 size buffer */
-            join(program_full_path, calculate->program_name);
+            join(program_full_path, main_config->program_name);
             if (exists(program_full_path)) {
                 break;
             }
@@ -713,9 +713,6 @@ calculate_init(PyCalculatePath *calculate,
                const _PyMainInterpreterConfig *main_config)
 {
     calculate->home = main_config->home;
-    calculate->module_search_path_env = main_config->module_search_path_env;
-    calculate->program_name = main_config->program_name;
-
     calculate->path_env = _wgetenv(L"PATH");
 }
 
@@ -815,7 +812,9 @@ 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(const _PyMainInterpreterConfig *main_config,
+                             PyCalculatePath *calculate, _PyPathConfig *config,
+                             wchar_t *prefix)
 {
     int skiphome = calculate->home==NULL ? 0 : 1;
 #ifdef Py_ENABLE_SHARED
@@ -824,7 +823,7 @@ calculate_module_search_path(PyCalculatePath *calculate, _PyPathConfig *config,
 #endif
     /* We only use the default relative PYTHONPATH if we haven't
        anything better to use! */
-    int skipdefault = (calculate->module_search_path_env!=NULL || calculate->home!=NULL || \
+    int skipdefault = (main_config->module_search_path_env!=NULL || calculate->home!=NULL || \
                        calculate->machine_path!=NULL || calculate->user_path!=NULL);
 
     /* We need to construct a path from the following parts.
@@ -861,8 +860,8 @@ calculate_module_search_path(PyCalculatePath *calculate, _PyPathConfig *config,
         bufsz += wcslen(calculate->machine_path) + 1;
     }
     bufsz += wcslen(calculate->zip_path) + 1;
-    if (calculate->module_search_path_env != NULL) {
-        bufsz += wcslen(calculate->module_search_path_env) + 1;
+    if (main_config->module_search_path_env != NULL) {
+        bufsz += wcslen(main_config->module_search_path_env) + 1;
     }
 
     wchar_t *buf, *start_buf;
@@ -870,9 +869,9 @@ calculate_module_search_path(PyCalculatePath *calculate, _PyPathConfig *config,
     if (buf == NULL) {
         /* We can't exit, so print a warning and limp along */
         fprintf(stderr, "Can't malloc dynamic PYTHONPATH.\n");
-        if (calculate->module_search_path_env) {
+        if (main_config->module_search_path_env) {
             fprintf(stderr, "Using environment $PYTHONPATH.\n");
-            config->module_search_path = calculate->module_search_path_env;
+            config->module_search_path = main_config->module_search_path_env;
         }
         else {
             fprintf(stderr, "Using default static path.\n");
@@ -882,8 +881,8 @@ calculate_module_search_path(PyCalculatePath *calculate, _PyPathConfig *config,
     }
     start_buf = buf;
 
-    if (calculate->module_search_path_env) {
-        if (wcscpy_s(buf, bufsz - (buf - start_buf), calculate->module_search_path_env)) {
+    if (main_config->module_search_path_env) {
+        if (wcscpy_s(buf, bufsz - (buf - start_buf), main_config->module_search_path_env)) {
             return INIT_ERR_BUFFER_OVERFLOW();
         }
         buf = wcschr(buf, L'\0');
@@ -996,8 +995,8 @@ calculate_module_search_path(PyCalculatePath *calculate, _PyPathConfig *config,
 
 
 static _PyInitError
-calculate_path_impl(PyCalculatePath *calculate, _PyPathConfig *config,
-                    const _PyMainInterpreterConfig *main_config)
+calculate_path_impl(const _PyMainInterpreterConfig *main_config,
+                    PyCalculatePath *calculate, _PyPathConfig *config)
 {
     _PyInitError err;
 
@@ -1006,7 +1005,7 @@ calculate_path_impl(PyCalculatePath *calculate, _PyPathConfig *config,
         return err;
     }
 
-    err = get_program_full_path(calculate, config);
+    err = get_program_full_path(main_config, calculate, config);
     if (_Py_INIT_FAILED(err)) {
         return err;
     }
@@ -1032,7 +1031,7 @@ calculate_path_impl(PyCalculatePath *calculate, _PyPathConfig *config,
 
     calculate_home_prefix(calculate, prefix);
 
-    err = calculate_module_search_path(calculate, config, prefix);
+    err = calculate_module_search_path(main_config, calculate, config, prefix);
     if (_Py_INIT_FAILED(err)) {
         return err;
     }
@@ -1092,7 +1091,7 @@ _PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
     _PyPathConfig new_path_config;
     memset(&new_path_config, 0, sizeof(new_path_config));
 
-    err = calculate_path_impl(&calculate, &new_path_config, main_config);
+    err = calculate_path_impl(main_config, &calculate, &new_path_config);
     if (_Py_INIT_FAILED(err)) {
         goto done;
     }
@@ -1121,14 +1120,26 @@ pathconfig_global_init(void)
     _PyMainInterpreterConfig config = _PyMainInterpreterConfig_INIT;
 
     err = _PyMainInterpreterConfig_ReadEnv(&config);
-    if (!_Py_INIT_FAILED(err)) {
-        err = _PyPathConfig_Init(&config);
+    if (_Py_INIT_FAILED(err)) {
+        goto error;
+    }
+
+    err = _PyMainInterpreterConfig_Read(&config);
+    if (_Py_INIT_FAILED(err)) {
+        goto error;
     }
-    _PyMainInterpreterConfig_Clear(&config);
 
+    err = _PyPathConfig_Init(&config);
     if (_Py_INIT_FAILED(err)) {
-        _Py_FatalInitError(err);
+        goto error;
     }
+
+    _PyMainInterpreterConfig_Clear(&config);
+    return;
+
+error:
+    _PyMainInterpreterConfig_Clear(&config);
+    _Py_FatalInitError(err);
 }