bpo-34170: Rework _PyCoreConfig_Read() to avoid side effect (GH-8353)

Rework _PyCoreConfig_Read() function which *reads* core configuration to not *modify* the path configuration. A new _PyCoreConfig_SetPathConfig() function now recreates the path configuration from the core configuration. This function is now called very late in _Py_InitializeCore(), just before calling initimport(). Changes: * Add _PyCoreConfig.dll_path * Py_SetPath() now fails with a fatal python error on memory allocation failure. * Rename _PyPathConfig_Calculate() to _PyPathConfig_Calculate_impl() * Replace _PyPathConfig_Init() with _PyPathConfig_Calculate(): the function now requires a _PyPathConfig * Add _PyPathConfig_SetGlobal() to set the _Py_path_config global variable. * Add _PyCoreConfig_InitPathConfig(): compute the path configuration * Add _PyCoreConfig_SetPathConfig(): set path configuration from core configuration * Rename wstrlist_append() to _Py_wstrlist_append() * _Py_wstrlist_append() now handles integer overflow.
python · Jul 21, 2018 · b1147e4 · b1147e4
1 parent 94487d4
commit b1147e4
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Showing 8 changed files with 358 additions and 146 deletions.
diff --git a/Include/internal/pystate.h b/Include/internal/pystate.h
@@ -37,7 +37,7 @@ struct _gilstate_runtime_state {
 #define _PyGILState_check_enabled _PyRuntime.gilstate.check_enabled
 
 
-typedef struct {
+typedef struct _PyPathConfig {
     /* Full path to the Python program */
     wchar_t *program_full_path;
     wchar_t *prefix;
@@ -59,11 +59,15 @@ typedef struct {
 
 PyAPI_DATA(_PyPathConfig) _Py_path_config;
 
-PyAPI_FUNC(_PyInitError) _PyPathConfig_Calculate(
+PyAPI_FUNC(_PyInitError) _PyPathConfig_Calculate_impl(
     _PyPathConfig *config,
     const _PyCoreConfig *core_config);
-PyAPI_FUNC(void) _PyPathConfig_Clear(_PyPathConfig *config);
+PyAPI_FUNC(void) _PyPathConfig_ClearGlobal(void);
 
+PyAPI_FUNC(_PyInitError) _Py_wstrlist_append(
+    int *len,
+    wchar_t ***list,
+    const wchar_t *str);
 
 /* interpreter state */
 

diff --git a/Include/pylifecycle.h b/Include/pylifecycle.h
@@ -59,6 +59,9 @@ PyAPI_FUNC(void) _PyCoreConfig_Clear(_PyCoreConfig *);
 PyAPI_FUNC(int) _PyCoreConfig_Copy(
     _PyCoreConfig *config,
     const _PyCoreConfig *config2);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_InitPathConfig(_PyCoreConfig *config);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetPathConfig(
+    const _PyCoreConfig *config);
 
 PyAPI_FUNC(_PyInitError) _PyMainInterpreterConfig_Read(
     _PyMainInterpreterConfig *config,
@@ -116,7 +119,11 @@ PyAPI_FUNC(wchar_t *) Py_GetPrefix(void);
 PyAPI_FUNC(wchar_t *) Py_GetExecPrefix(void);
 PyAPI_FUNC(wchar_t *) Py_GetPath(void);
 #ifdef Py_BUILD_CORE
-PyAPI_FUNC(_PyInitError) _PyPathConfig_Init(const _PyCoreConfig *core_config);
+struct _PyPathConfig;
+typedef struct _PyPathConfig _PyPathConfig;
+
+PyAPI_FUNC(_PyInitError) _PyPathConfig_SetGlobal(
+    const _PyPathConfig *config);
 PyAPI_FUNC(PyObject*) _PyPathConfig_ComputeArgv0(int argc, wchar_t **argv);
 PyAPI_FUNC(int) _Py_FindEnvConfigValue(
     FILE *env_file,

diff --git a/Include/pystate.h b/Include/pystate.h
@@ -71,6 +71,9 @@ typedef struct {
     wchar_t *base_prefix;   /* sys.base_prefix */
     wchar_t *exec_prefix;   /* sys.exec_prefix */
     wchar_t *base_exec_prefix;  /* sys.base_exec_prefix */
+#ifdef MS_WINDOWS
+    wchar_t *dll_path;      /* Windows DLL path */
+#endif
 
     /* Private fields */
     int _disable_importlib; /* Needed by freeze_importlib */

diff --git a/Modules/getpath.c b/Modules/getpath.c
@@ -946,7 +946,7 @@ calculate_path_impl(const _PyCoreConfig *core_config,
 
 
 _PyInitError
-_PyPathConfig_Calculate(_PyPathConfig *config, const _PyCoreConfig *core_config)
+_PyPathConfig_Calculate_impl(_PyPathConfig *config, const _PyCoreConfig *core_config)
 {
     PyCalculatePath calculate;
     memset(&calculate, 0, sizeof(calculate));

diff --git a/Modules/main.c b/Modules/main.c
@@ -650,7 +650,7 @@ pymain_free_raw(_PyMain *pymain)
        configuration options set before Py_Initialize() which should
        remain valid after Py_Finalize(), since
        Py_Initialize()-Py_Finalize() can be called multiple times. */
-    _PyPathConfig_Clear(&_Py_path_config);
+    _PyPathConfig_ClearGlobal();
 
     pymain_clear_config(pymain);
 
@@ -701,9 +701,13 @@ pymain_run_main_from_importer(_PyMain *pymain)
 }
 
 
-static _PyInitError
-wstrlist_append(int *len, wchar_t ***list, const wchar_t *str)
+_PyInitError
+_Py_wstrlist_append(int *len, wchar_t ***list, const wchar_t *str)
 {
+    if (*len == INT_MAX) {
+        /* len+1 would overflow */
+        return _Py_INIT_NO_MEMORY();
+    }
     wchar_t *str2 = _PyMem_RawWcsdup(str);
     if (str2 == NULL) {
         return _Py_INIT_NO_MEMORY();
@@ -725,7 +729,7 @@ wstrlist_append(int *len, wchar_t ***list, const wchar_t *str)
 static int
 pymain_wstrlist_append(_PyMain *pymain, int *len, wchar_t ***list, const wchar_t *str)
 {
-    _PyInitError err = wstrlist_append(len, list, str);
+    _PyInitError err = _Py_wstrlist_append(len, list, str);
     if (_Py_INIT_FAILED(err)) {
         pymain->err = err;
         return -1;
@@ -972,9 +976,9 @@ static _PyInitError
 config_add_warnings_optlist(_PyCoreConfig *config, int len, wchar_t **options)
 {
     for (int i = 0; i < len; i++) {
-        _PyInitError err = wstrlist_append(&config->nwarnoption,
-                                           &config->warnoptions,
-                                           options[i]);
+        _PyInitError err = _Py_wstrlist_append(&config->nwarnoption,
+                                               &config->warnoptions,
+                                               options[i]);
         if (_Py_INIT_FAILED(err)) {
             return err;
         }
@@ -1006,9 +1010,9 @@ config_init_warnoptions(_PyCoreConfig *config, _Py_CommandLineDetails *cmdline)
      */
 
     if (config->dev_mode) {
-        err = wstrlist_append(&config->nwarnoption,
-                              &config->warnoptions,
-                              L"default");
+        err = _Py_wstrlist_append(&config->nwarnoption,
+                                  &config->warnoptions,
+                                  L"default");
         if (_Py_INIT_FAILED(err)) {
             return err;
         }
@@ -1040,9 +1044,9 @@ config_init_warnoptions(_PyCoreConfig *config, _Py_CommandLineDetails *cmdline)
         else {
             filter = L"default::BytesWarning";
         }
-        err = wstrlist_append(&config->nwarnoption,
-                              &config->warnoptions,
-                              filter);
+        err = _Py_wstrlist_append(&config->nwarnoption,
+                                  &config->warnoptions,
+                                  filter);
         if (_Py_INIT_FAILED(err)) {
             return err;
         }
@@ -1077,9 +1081,9 @@ cmdline_init_env_warnoptions(_Py_CommandLineDetails *cmdline)
          warning != NULL;
          warning = WCSTOK(NULL, L",", &context))
     {
-        _PyInitError err = wstrlist_append(&cmdline->nenv_warnoption,
-                                           &cmdline->env_warnoptions,
-                                          warning);
+        _PyInitError err = _Py_wstrlist_append(&cmdline->nenv_warnoption,
+                                               &cmdline->env_warnoptions,
+                                               warning);
         if (_Py_INIT_FAILED(err)) {
             PyMem_RawFree(env);
             return err;
@@ -2099,101 +2103,6 @@ config_init_locale(_PyCoreConfig *config)
 }
 
 
-static _PyInitError
-config_init_module_search_paths(_PyCoreConfig *config)
-{
-    assert(config->module_search_paths == NULL);
-    assert(config->nmodule_search_path < 0);
-
-    config->nmodule_search_path = 0;
-
-    const wchar_t *sys_path = Py_GetPath();
-    const wchar_t delim = DELIM;
-    const wchar_t *p = sys_path;
-    while (1) {
-        p = wcschr(sys_path, delim);
-        if (p == NULL) {
-            p = sys_path + wcslen(sys_path); /* End of string */
-        }
-
-        size_t path_len = (p - sys_path);
-        wchar_t *path = PyMem_RawMalloc((path_len + 1) * sizeof(wchar_t));
-        if (path == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-        memcpy(path, sys_path, path_len * sizeof(wchar_t));
-        path[path_len] = L'\0';
-
-        _PyInitError err = wstrlist_append(&config->nmodule_search_path,
-                                           &config->module_search_paths,
-                                           path);
-        PyMem_RawFree(path);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-
-        if (*p == '\0') {
-            break;
-        }
-        sys_path = p + 1;
-    }
-    return _Py_INIT_OK();
-}
-
-
-static _PyInitError
-config_init_path_config(_PyCoreConfig *config)
-{
-    _PyInitError err = _PyPathConfig_Init(config);
-    if (_Py_INIT_FAILED(err)) {
-        return err;
-    }
-
-    if (config->nmodule_search_path < 0) {
-        err = config_init_module_search_paths(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    if (config->executable == NULL) {
-        config->executable = _PyMem_RawWcsdup(Py_GetProgramFullPath());
-        if (config->executable == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-    }
-
-    if (config->prefix == NULL) {
-        config->prefix = _PyMem_RawWcsdup(Py_GetPrefix());
-        if (config->prefix == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-    }
-
-    if (config->exec_prefix == NULL) {
-        config->exec_prefix = _PyMem_RawWcsdup(Py_GetExecPrefix());
-        if (config->exec_prefix == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-    }
-
-    if (config->base_prefix == NULL) {
-        config->base_prefix = _PyMem_RawWcsdup(config->prefix);
-        if (config->base_prefix == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-    }
-
-    if (config->base_exec_prefix == NULL) {
-        config->base_exec_prefix = _PyMem_RawWcsdup(config->exec_prefix);
-        if (config->base_exec_prefix == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-    }
-
-    return _Py_INIT_OK();
-}
-
 /* Read configuration settings from standard locations
  *
  * This function doesn't make any changes to the interpreter state - it
@@ -2252,7 +2161,7 @@ _PyCoreConfig_Read(_PyCoreConfig *config)
     }
 
     if (!config->_disable_importlib) {
-        err = config_init_path_config(config);
+        err = _PyCoreConfig_InitPathConfig(config);
         if (_Py_INIT_FAILED(err)) {
             return err;
         }
@@ -2294,6 +2203,9 @@ _PyCoreConfig_Clear(_PyCoreConfig *config)
     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
@@ -2356,6 +2268,9 @@ _PyCoreConfig_Copy(_PyCoreConfig *config, const _PyCoreConfig *config2)
     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);
 
 #undef COPY_ATTR

diff --git a/PC/getpathp.c b/PC/getpathp.c
@@ -1000,7 +1000,7 @@ calculate_free(PyCalculatePath *calculate)
 
 
 _PyInitError
-_PyPathConfig_Calculate(_PyPathConfig *config, const _PyCoreConfig *core_config)
+_PyPathConfig_Calculate_impl(_PyPathConfig *config, const _PyCoreConfig *core_config)
 {
     PyCalculatePath calculate;
     memset(&calculate, 0, sizeof(calculate));