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.
diff --git a/Python/pathconfig.c b/Python/pathconfig.c
index 07aa01c..e987df1 100644
--- a/Python/pathconfig.c
+++ b/Python/pathconfig.c
@@ -13,7 +13,23 @@
_PyPathConfig _Py_path_config = _PyPathConfig_INIT;
-void
+static int
+copy_wstr(wchar_t **dst, const wchar_t *src)
+{
+ if (src != NULL) {
+ *dst = _PyMem_RawWcsdup(src);
+ if (*dst == NULL) {
+ return -1;
+ }
+ }
+ else {
+ *dst = NULL;
+ }
+ return 0;
+}
+
+
+static void
_PyPathConfig_Clear(_PyPathConfig *config)
{
/* _PyMem_SetDefaultAllocator() is needed to get a known memory allocator,
@@ -44,16 +60,11 @@
}
-/* Initialize paths for Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix()
- and Py_GetProgramFullPath() */
-_PyInitError
-_PyPathConfig_Init(const _PyCoreConfig *core_config)
+/* Calculate the path configuration: initialize path_config from core_config */
+static _PyInitError
+_PyPathConfig_Calculate(_PyPathConfig *path_config,
+ const _PyCoreConfig *core_config)
{
- if (_Py_path_config.module_search_path) {
- /* Already initialized */
- return _Py_INIT_OK();
- }
-
_PyInitError err;
_PyPathConfig new_config = _PyPathConfig_INIT;
@@ -62,31 +73,67 @@
/* Calculate program_full_path, prefix, exec_prefix (Unix)
or dll_path (Windows), and module_search_path */
- err = _PyPathConfig_Calculate(&new_config, core_config);
+ err = _PyPathConfig_Calculate_impl(&new_config, core_config);
if (_Py_INIT_FAILED(err)) {
- _PyPathConfig_Clear(&new_config);
- goto done;
+ goto err;
}
/* Copy home and program_name from core_config */
- if (core_config->home != NULL) {
- new_config.home = _PyMem_RawWcsdup(core_config->home);
- if (new_config.home == NULL) {
- err = _Py_INIT_NO_MEMORY();
- goto done;
- }
+ if (copy_wstr(&new_config.home, core_config->home) < 0) {
+ err = _Py_INIT_NO_MEMORY();
+ goto err;
}
- else {
- new_config.home = NULL;
+ if (copy_wstr(&new_config.program_name, core_config->program_name) < 0) {
+ err = _Py_INIT_NO_MEMORY();
+ goto err;
}
- new_config.program_name = _PyMem_RawWcsdup(core_config->program_name);
- if (new_config.program_name == NULL) {
- err = _Py_INIT_NO_MEMORY();
- goto done;
- }
+ _PyPathConfig_Clear(path_config);
+ *path_config = new_config;
+
+ err = _Py_INIT_OK();
+ goto done;
+
+err:
+ _PyPathConfig_Clear(&new_config);
+
+done:
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+ return err;
+}
+
+
+_PyInitError
+_PyPathConfig_SetGlobal(const _PyPathConfig *config)
+{
+ _PyInitError err;
+ _PyPathConfig new_config = _PyPathConfig_INIT;
+
+ PyMemAllocatorEx old_alloc;
+ _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+#define COPY_ATTR(ATTR) \
+ do { \
+ if (copy_wstr(&new_config.ATTR, config->ATTR) < 0) { \
+ _PyPathConfig_Clear(&new_config); \
+ err = _Py_INIT_NO_MEMORY(); \
+ goto done; \
+ } \
+ } while (0)
+
+ COPY_ATTR(program_full_path);
+ COPY_ATTR(prefix);
+#ifdef MS_WINDOWS
+ COPY_ATTR(dll_path);
+#else
+ COPY_ATTR(exec_prefix);
+#endif
+ COPY_ATTR(module_search_path);
+ COPY_ATTR(program_name);
+ COPY_ATTR(home);
_PyPathConfig_Clear(&_Py_path_config);
+ /* Steal new_config strings; don't clear new_config */
_Py_path_config = new_config;
err = _Py_INIT_OK();
@@ -97,15 +144,228 @@
}
+void
+_PyPathConfig_ClearGlobal(void)
+{
+ _PyPathConfig_Clear(&_Py_path_config);
+}
+
+
+static wchar_t*
+wstrlist_join(wchar_t sep, int count, wchar_t **list)
+{
+ size_t len = 1; /* NUL terminator */
+ for (int i=0; i < count; i++) {
+ if (i != 0) {
+ len++;
+ }
+ len += wcslen(list[i]);
+ }
+
+ wchar_t *text = PyMem_RawMalloc(len * sizeof(wchar_t));
+ if (text == NULL) {
+ return NULL;
+ }
+ wchar_t *str = text;
+ for (int i=0; i < count; i++) {
+ wchar_t *path = list[i];
+ if (i != 0) {
+ *str++ = SEP;
+ }
+ len = wcslen(path);
+ memcpy(str, path, len * sizeof(wchar_t));
+ str += len;
+ }
+ *str = L'\0';
+
+ return text;
+}
+
+
+/* Set the global path configuration from core_config. */
+_PyInitError
+_PyCoreConfig_SetPathConfig(const _PyCoreConfig *core_config)
+{
+ PyMemAllocatorEx old_alloc;
+ _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+ _PyInitError err;
+ _PyPathConfig path_config = _PyPathConfig_INIT;
+
+ path_config.module_search_path = wstrlist_join(DELIM,
+ core_config->nmodule_search_path,
+ core_config->module_search_paths);
+ if (path_config.module_search_path == NULL) {
+ goto no_memory;
+ }
+
+ if (copy_wstr(&path_config.program_full_path, core_config->executable) < 0) {
+ goto no_memory;
+ }
+ if (copy_wstr(&path_config.prefix, core_config->prefix) < 0) {
+ goto no_memory;
+ }
+#ifdef MS_WINDOWS
+ if (copy_wstr(&path_config.dll_path, core_config->dll_path) < 0) {
+ goto no_memory;
+ }
+#else
+ if (copy_wstr(&path_config.exec_prefix, core_config->exec_prefix) < 0) {
+ goto no_memory;
+ }
+#endif
+ if (copy_wstr(&path_config.program_name, core_config->program_name) < 0) {
+ goto no_memory;
+ }
+ if (copy_wstr(&path_config.home, core_config->home) < 0) {
+ goto no_memory;
+ }
+
+ err = _PyPathConfig_SetGlobal(&path_config);
+ if (_Py_INIT_FAILED(err)) {
+ goto done;
+ }
+
+ err = _Py_INIT_OK();
+ goto done;
+
+no_memory:
+ err = _Py_INIT_NO_MEMORY();
+
+done:
+ _PyPathConfig_Clear(&path_config);
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+ return err;
+}
+
+
+static _PyInitError
+core_config_init_module_search_paths(_PyCoreConfig *config,
+ _PyPathConfig *path_config)
+{
+ assert(config->module_search_paths == NULL);
+ assert(config->nmodule_search_path < 0);
+
+ config->nmodule_search_path = 0;
+
+ const wchar_t *sys_path = path_config->module_search_path;
+ 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 = _Py_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();
+}
+
+
+_PyInitError
+_PyCoreConfig_InitPathConfig(_PyCoreConfig *config)
+{
+ _PyPathConfig path_config = _PyPathConfig_INIT;
+ _PyInitError err;
+
+ err = _PyPathConfig_Calculate(&path_config, config);
+ if (_Py_INIT_FAILED(err)) {
+ goto error;
+ }
+
+ if (config->nmodule_search_path < 0) {
+ err = core_config_init_module_search_paths(config, &path_config);
+ if (_Py_INIT_FAILED(err)) {
+ goto error;
+ }
+ }
+
+ if (config->executable == NULL) {
+ if (copy_wstr(&config->executable,
+ path_config.program_full_path) < 0) {
+ goto no_memory;
+ }
+ }
+
+ if (config->prefix == NULL) {
+ if (copy_wstr(&config->prefix, path_config.prefix) < 0) {
+ goto no_memory;
+ }
+ }
+
+ if (config->exec_prefix == NULL) {
+#ifdef MS_WINDOWS
+ wchar_t *exec_prefix = path_config.prefix;
+#else
+ wchar_t *exec_prefix = path_config.exec_prefix;
+#endif
+ if (copy_wstr(&config->exec_prefix, exec_prefix) < 0) {
+ goto no_memory;
+ }
+ }
+
+#ifdef MS_WINDOWS
+ if (config->dll_path == NULL) {
+ if (copy_wstr(&config->dll_path, path_config.dll_path) < 0) {
+ goto no_memory;
+ }
+ }
+#endif
+
+ if (config->base_prefix == NULL) {
+ if (copy_wstr(&config->base_prefix, config->prefix) < 0) {
+ goto no_memory;
+ }
+ }
+
+ if (config->base_exec_prefix == NULL) {
+ if (copy_wstr(&config->base_exec_prefix, config->exec_prefix) < 0) {
+ goto no_memory;
+ }
+ }
+
+ _PyPathConfig_Clear(&path_config);
+ return _Py_INIT_OK();
+
+no_memory:
+ err = _Py_INIT_NO_MEMORY();
+
+error:
+ _PyPathConfig_Clear(&path_config);
+ return err;
+}
+
+
static void
pathconfig_global_init(void)
{
- if (_Py_path_config.module_search_path) {
+ if (_Py_path_config.module_search_path != NULL) {
/* Already initialized */
return;
}
_PyInitError err;
+ _PyPathConfig path_config = _PyPathConfig_INIT;
_PyCoreConfig config = _PyCoreConfig_INIT;
err = _PyCoreConfig_Read(&config);
@@ -113,15 +373,22 @@
goto error;
}
- err = _PyPathConfig_Init(&config);
+ err = _PyPathConfig_Calculate(&path_config, &config);
if (_Py_INIT_FAILED(err)) {
goto error;
}
+ err = _PyPathConfig_SetGlobal(&path_config);
+ if (_Py_INIT_FAILED(err)) {
+ goto error;
+ }
+
+ _PyPathConfig_Clear(&path_config);
_PyCoreConfig_Clear(&config);
return;
error:
+ _PyPathConfig_Clear(&path_config);
_PyCoreConfig_Clear(&config);
_Py_FatalInitError(err);
}
@@ -142,13 +409,18 @@
_PyPathConfig new_config;
new_config.program_full_path = _PyMem_RawWcsdup(Py_GetProgramName());
+ int alloc_error = (new_config.program_full_path == NULL);
new_config.prefix = _PyMem_RawWcsdup(L"");
+ alloc_error |= (new_config.prefix == NULL);
#ifdef MS_WINDOWS
new_config.dll_path = _PyMem_RawWcsdup(L"");
+ alloc_error |= (new_config.dll_path == NULL);
#else
new_config.exec_prefix = _PyMem_RawWcsdup(L"");
+ alloc_error |= (new_config.exec_prefix == NULL);
#endif
new_config.module_search_path = _PyMem_RawWcsdup(path);
+ alloc_error |= (new_config.module_search_path == NULL);
/* steal the home and program_name values (to leave them unchanged) */
new_config.home = _Py_path_config.home;
@@ -160,6 +432,10 @@
_Py_path_config = new_config;
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+ if (alloc_error) {
+ Py_FatalError("Py_SetPath() failed: out of memory");
+ }
}