bpo-36142: Add _PyPreConfig_SetAllocator() (GH-12187)
* _PyPreConfig_Write() now reallocates the pre-configuration with the
new memory allocator.
* It is no longer needed to force the "default raw memory allocator"
to clear pre-configuration and core configuration. Simplify the
code.
* _PyPreConfig_Write() now does nothing if called after
Py_Initialize(): no longer check if the allocator is the same.
* Remove _PyMem_GetDebugAllocatorsName(): dev mode sets again
allocator to "debug".
diff --git a/Python/preconfig.c b/Python/preconfig.c
index 6924203..ee9dca4 100644
--- a/Python/preconfig.c
+++ b/Python/preconfig.c
@@ -125,15 +125,8 @@
void
_PyPreConfig_Clear(_PyPreConfig *config)
{
-#define CLEAR(ATTR) \
- do { \
- PyMem_RawFree(ATTR); \
- ATTR = NULL; \
- } while (0)
-
- CLEAR(config->allocator);
-
-#undef CLEAR
+ PyMem_RawFree(config->allocator);
+ config->allocator = NULL;
}
@@ -453,8 +446,7 @@
/* allocator */
if (config->dev_mode && config->allocator == NULL) {
- const char *allocator = _PyMem_GetDebugAllocatorsName();
- config->allocator = _PyMem_RawStrdup(allocator);
+ config->allocator = _PyMem_RawStrdup("debug");
if (config->allocator == NULL) {
return _Py_INIT_NO_MEMORY();
}
@@ -742,31 +734,56 @@
static _PyInitError
-_PyPreConfig_Reconfigure(const _PyPreConfig *config)
+_PyPreConfig_SetAllocator(_PyPreConfig *config)
{
- if (config->allocator != NULL) {
- const char *allocator = _PyMem_GetAllocatorsName();
- if (allocator == NULL || strcmp(config->allocator, allocator) != 0) {
- return _Py_INIT_USER_ERR("cannot modify memory allocator "
- "after first Py_Initialize()");
- }
+ assert(!_PyRuntime.core_initialized);
+
+ PyMemAllocatorEx old_alloc;
+ PyMem_GetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+ if (_PyMem_SetupAllocators(config->allocator) < 0) {
+ return _Py_INIT_USER_ERR("Unknown PYTHONMALLOC allocator");
}
+
+ /* Copy the pre-configuration with the new allocator */
+ _PyPreConfig config2 = _PyPreConfig_INIT;
+ if (_PyPreConfig_Copy(&config2, config) < 0) {
+ _PyPreConfig_Clear(&config2);
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+ return _Py_INIT_NO_MEMORY();
+ }
+
+ /* Free the old config and replace config with config2. Since config now
+ owns the data, don't free config2. */
+ PyMemAllocatorEx new_alloc;
+ PyMem_GetAllocator(PYMEM_DOMAIN_RAW, &new_alloc);
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+ _PyPreConfig_Clear(config);
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &new_alloc);
+
+ *config = config2;
+
return _Py_INIT_OK();
}
+/* Write the pre-configuration.
+
+ If the memory allocator is changed, config is re-allocated with new
+ allocator. So calling _PyPreConfig_Clear(config) is safe after this call. */
_PyInitError
-_PyPreConfig_Write(const _PyPreConfig *config)
+_PyPreConfig_Write(_PyPreConfig *config)
{
if (_PyRuntime.core_initialized) {
/* bpo-34008: Calling Py_Main() after Py_Initialize() ignores
the new configuration. */
- return _PyPreConfig_Reconfigure(config);
+ return _Py_INIT_OK();
}
if (config->allocator != NULL) {
- if (_PyMem_SetupAllocators(config->allocator) < 0) {
- return _Py_INIT_USER_ERR("Unknown PYTHONMALLOC allocator");
+ _PyInitError err = _PyPreConfig_SetAllocator(config);
+ if (_Py_INIT_FAILED(err)) {
+ return err;
}
}