/* Module definition and import implementation */

#include "Python.h"

#include "pycore_import.h" // _PyImport_BootstrapImp()

#include "pycore_initconfig.h" // _PyStatus_OK()

#include "pycore_interp.h" // struct _import_runtime_state

#include "pycore_namespace.h" // _PyNamespace_Type

#include "pycore_pyerrors.h" // _PyErr_SetString()

#include "pycore_pyhash.h" // _Py_KeyedHash()

#include "pycore_pylifecycle.h"

#include "pycore_pymem.h" // _PyMem_SetDefaultAllocator()

#include "pycore_pystate.h" // _PyInterpreterState_GET()

#include "pycore_sysmodule.h" // _PySys_Audit()

#include "marshal.h" // PyMarshal_ReadObjectFromString()

#include "importdl.h" // _PyImport_DynLoadFiletab

#include "pydtrace.h" // PyDTrace_IMPORT_FIND_LOAD_START_ENABLED()

#include <stdbool.h> // bool

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#ifdef __cplusplus

extern "C" {

#endif

/*[clinic input]

module _imp

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=9c332475d8686284]*/

#include "clinic/import.c.h"

/*******************************/

/* process-global import state */

/*******************************/

/* This table is defined in config.c: */

extern struct _inittab _PyImport_Inittab[];

// This is not used after Py_Initialize() is called.

// (See _PyRuntimeState.imports.inittab.)

struct _inittab *PyImport_Inittab = _PyImport_Inittab;

// When we dynamically allocate a larger table for PyImport_ExtendInittab(),

// we track the pointer here so we can deallocate it during finalization.

static struct _inittab *inittab_copy = NULL;

/*******************************/

/* runtime-global import state */

/*******************************/

#define INITTAB _PyRuntime.imports.inittab

#define LAST_MODULE_INDEX _PyRuntime.imports.last_module_index

#define EXTENSIONS _PyRuntime.imports.extensions

#define PKGCONTEXT (_PyRuntime.imports.pkgcontext)

/*******************************/

/* interpreter import state */

/*******************************/

#define MODULES(interp) \

(interp)->imports.modules

#define MODULES_BY_INDEX(interp) \

(interp)->imports.modules_by_index

#define IMPORTLIB(interp) \

(interp)->imports.importlib

#define OVERRIDE_MULTI_INTERP_EXTENSIONS_CHECK(interp) \

(interp)->imports.override_multi_interp_extensions_check

#define OVERRIDE_FROZEN_MODULES(interp) \

(interp)->imports.override_frozen_modules

#ifdef HAVE_DLOPEN

# define DLOPENFLAGS(interp) \

(interp)->imports.dlopenflags

#endif

#define IMPORT_FUNC(interp) \

(interp)->imports.import_func

#define IMPORT_LOCK(interp) \

(interp)->imports.lock.mutex

#define IMPORT_LOCK_THREAD(interp) \

(interp)->imports.lock.thread

#define IMPORT_LOCK_LEVEL(interp) \

(interp)->imports.lock.level

#define FIND_AND_LOAD(interp) \

(interp)->imports.find_and_load

/*******************/

/* the import lock */

/*******************/

/* Locking primitives to prevent parallel imports of the same module

in different threads to return with a partially loaded module.

These calls are serialized by the global interpreter lock. */

void

_PyImport_AcquireLock(PyInterpreterState *interp)

{

unsigned long me = PyThread_get_thread_ident();

if (me == PYTHREAD_INVALID_THREAD_ID)

return; /* Too bad */

if (IMPORT_LOCK(interp) == NULL) {

IMPORT_LOCK(interp) = PyThread_allocate_lock();

if (IMPORT_LOCK(interp) == NULL)

return; /* Nothing much we can do. */

}

if (IMPORT_LOCK_THREAD(interp) == me) {

IMPORT_LOCK_LEVEL(interp)++;

return;

}

if (IMPORT_LOCK_THREAD(interp) != PYTHREAD_INVALID_THREAD_ID ||

!PyThread_acquire_lock(IMPORT_LOCK(interp), 0))

{

PyThreadState *tstate = PyEval_SaveThread();

PyThread_acquire_lock(IMPORT_LOCK(interp), WAIT_LOCK);

PyEval_RestoreThread(tstate);

}

assert(IMPORT_LOCK_LEVEL(interp) == 0);

IMPORT_LOCK_THREAD(interp) = me;

IMPORT_LOCK_LEVEL(interp) = 1;

}

int

_PyImport_ReleaseLock(PyInterpreterState *interp)

{

unsigned long me = PyThread_get_thread_ident();

if (me == PYTHREAD_INVALID_THREAD_ID || IMPORT_LOCK(interp) == NULL)

return 0; /* Too bad */

if (IMPORT_LOCK_THREAD(interp) != me)

return -1;

IMPORT_LOCK_LEVEL(interp)--;

assert(IMPORT_LOCK_LEVEL(interp) >= 0);

if (IMPORT_LOCK_LEVEL(interp) == 0) {

IMPORT_LOCK_THREAD(interp) = PYTHREAD_INVALID_THREAD_ID;

PyThread_release_lock(IMPORT_LOCK(interp));

}

return 1;

}

#ifdef HAVE_FORK

/* This function is called from PyOS_AfterFork_Child() to ensure that newly

created child processes do not share locks with the parent.

We now acquire the import lock around fork() calls but on some platforms

(Solaris 9 and earlier? see isue7242) that still left us with problems. */

PyStatus

_PyImport_ReInitLock(PyInterpreterState *interp)

{

if (IMPORT_LOCK(interp) != NULL) {

if (_PyThread_at_fork_reinit(&IMPORT_LOCK(interp)) < 0) {

return _PyStatus_ERR("failed to create a new lock");

}

}

if (IMPORT_LOCK_LEVEL(interp) > 1) {

/* Forked as a side effect of import */

unsigned long me = PyThread_get_thread_ident();

PyThread_acquire_lock(IMPORT_LOCK(interp), WAIT_LOCK);

IMPORT_LOCK_THREAD(interp) = me;

IMPORT_LOCK_LEVEL(interp)--;

} else {

IMPORT_LOCK_THREAD(interp) = PYTHREAD_INVALID_THREAD_ID;

IMPORT_LOCK_LEVEL(interp) = 0;

}

return _PyStatus_OK();

}

#endif

/***************/

/* sys.modules */

/***************/

PyObject *

_PyImport_InitModules(PyInterpreterState *interp)

{

assert(MODULES(interp) == NULL);

MODULES(interp) = PyDict_New();

if (MODULES(interp) == NULL) {

return NULL;

}

return MODULES(interp);

}

PyObject *

_PyImport_GetModules(PyInterpreterState *interp)

{

return MODULES(interp);

}

void

_PyImport_ClearModules(PyInterpreterState *interp)

{

Py_SETREF(MODULES(interp), NULL);

}

PyObject *

PyImport_GetModuleDict(void)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

if (MODULES(interp) == NULL) {

Py_FatalError("interpreter has no modules dictionary");

}

return MODULES(interp);

}

// This is only kept around for extensions that use _Py_IDENTIFIER.

PyObject *

_PyImport_GetModuleId(_Py_Identifier *nameid)

{

PyObject *name = _PyUnicode_FromId(nameid); /* borrowed */

if (name == NULL) {

return NULL;

}

return PyImport_GetModule(name);

}

int

_PyImport_SetModule(PyObject *name, PyObject *m)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

PyObject *modules = MODULES(interp);

return PyObject_SetItem(modules, name, m);

}

int

_PyImport_SetModuleString(const char *name, PyObject *m)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

PyObject *modules = MODULES(interp);

return PyMapping_SetItemString(modules, name, m);

}

static PyObject *

import_get_module(PyThreadState *tstate, PyObject *name)

{

PyObject *modules = MODULES(tstate->interp);

if (modules == NULL) {

_PyErr_SetString(tstate, PyExc_RuntimeError,

"unable to get sys.modules");

return NULL;

}

PyObject *m;

Py_INCREF(modules);

if (PyDict_CheckExact(modules)) {

m = PyDict_GetItemWithError(modules, name); /* borrowed */

Py_XINCREF(m);

}

else {

m = PyObject_GetItem(modules, name);

if (m == NULL && _PyErr_ExceptionMatches(tstate, PyExc_KeyError)) {

_PyErr_Clear(tstate);

}

}

Py_DECREF(modules);

return m;

}

static int

import_ensure_initialized(PyInterpreterState *interp, PyObject *mod, PyObject *name)

{

PyObject *spec;

/* Optimization: only call _bootstrap._lock_unlock_module() if

__spec__._initializing is true.

NOTE: because of this, initializing must be set *before*

stuffing the new module in sys.modules.

*/

spec = PyObject_GetAttr(mod, &_Py_ID(__spec__));

int busy = _PyModuleSpec_IsInitializing(spec);

Py_XDECREF(spec);

if (busy) {

/* Wait until module is done importing. */

PyObject *value = _PyObject_CallMethodOneArg(

IMPORTLIB(interp), &_Py_ID(_lock_unlock_module), name);

if (value == NULL) {

return -1;

}

Py_DECREF(value);

}

return 0;

}

static void remove_importlib_frames(PyThreadState *tstate);

PyObject *

PyImport_GetModule(PyObject *name)

{

PyThreadState *tstate = _PyThreadState_GET();

PyObject *mod;

mod = import_get_module(tstate, name);

if (mod != NULL && mod != Py_None) {

if (import_ensure_initialized(tstate->interp, mod, name) < 0) {

Py_DECREF(mod);

remove_importlib_frames(tstate);

return NULL;

}

}

return mod;

}

/* Get the module object corresponding to a module name.

First check the modules dictionary if there's one there,

if not, create a new one and insert it in the modules dictionary. */

static PyObject *

import_add_module(PyThreadState *tstate, PyObject *name)

{

PyObject *modules = MODULES(tstate->interp);

if (modules == NULL) {

_PyErr_SetString(tstate, PyExc_RuntimeError,

"no import module dictionary");

return NULL;

}

PyObject *m;

if (PyDict_CheckExact(modules)) {

m = Py_XNewRef(PyDict_GetItemWithError(modules, name));

}

else {

m = PyObject_GetItem(modules, name);

// For backward-compatibility we copy the behavior

// of PyDict_GetItemWithError().

if (_PyErr_ExceptionMatches(tstate, PyExc_KeyError)) {

_PyErr_Clear(tstate);

}

}

if (_PyErr_Occurred(tstate)) {

return NULL;

}

if (m != NULL && PyModule_Check(m)) {

return m;

}

Py_XDECREF(m);

m = PyModule_NewObject(name);

if (m == NULL)

return NULL;

if (PyObject_SetItem(modules, name, m) != 0) {

Py_DECREF(m);

return NULL;

}

return m;

}

PyObject *

PyImport_AddModuleObject(PyObject *name)

{

PyThreadState *tstate = _PyThreadState_GET();

PyObject *mod = import_add_module(tstate, name);

if (mod) {

PyObject *ref = PyWeakref_NewRef(mod, NULL);

Py_DECREF(mod);

if (ref == NULL) {

return NULL;

}

mod = PyWeakref_GetObject(ref);

Py_DECREF(ref);

}

return mod; /* borrowed reference */

}

PyObject *

PyImport_AddModule(const char *name)

{

PyObject *nameobj = PyUnicode_FromString(name);

if (nameobj == NULL) {

return NULL;

}

PyObject *module = PyImport_AddModuleObject(nameobj);

Py_DECREF(nameobj);

return module;

}

/* Remove name from sys.modules, if it's there.

* Can be called with an exception raised.

* If fail to remove name a new exception will be chained with the old

* exception, otherwise the old exception is preserved.

*/

static void

remove_module(PyThreadState *tstate, PyObject *name)

{

PyObject *exc = _PyErr_GetRaisedException(tstate);

PyObject *modules = MODULES(tstate->interp);

if (PyDict_CheckExact(modules)) {

PyObject *mod = _PyDict_Pop(modules, name, Py_None);

Py_XDECREF(mod);

}

else if (PyMapping_DelItem(modules, name) < 0) {

if (_PyErr_ExceptionMatches(tstate, PyExc_KeyError)) {

_PyErr_Clear(tstate);

}

}

_PyErr_ChainExceptions1(exc);

}

/************************************/

/* per-interpreter modules-by-index */

/************************************/

Py_ssize_t

_PyImport_GetNextModuleIndex(void)

{

LAST_MODULE_INDEX++;

return LAST_MODULE_INDEX;

}

static const char *

_modules_by_index_check(PyInterpreterState *interp, Py_ssize_t index)

{

if (index == 0) {

return "invalid module index";

}

if (MODULES_BY_INDEX(interp) == NULL) {

return "Interpreters module-list not accessible.";

}

if (index > PyList_GET_SIZE(MODULES_BY_INDEX(interp))) {

return "Module index out of bounds.";

}

return NULL;

}

static PyObject *

_modules_by_index_get(PyInterpreterState *interp, PyModuleDef *def)

{

Py_ssize_t index = def->m_base.m_index;

if (_modules_by_index_check(interp, index) != NULL) {

return NULL;

}

PyObject *res = PyList_GET_ITEM(MODULES_BY_INDEX(interp), index);

return res==Py_None ? NULL : res;

}

static int

_modules_by_index_set(PyInterpreterState *interp,

PyModuleDef *def, PyObject *module)

{

assert(def != NULL);

assert(def->m_slots == NULL);

assert(def->m_base.m_index > 0);

if (MODULES_BY_INDEX(interp) == NULL) {

MODULES_BY_INDEX(interp) = PyList_New(0);

if (MODULES_BY_INDEX(interp) == NULL) {

return -1;

}

}

Py_ssize_t index = def->m_base.m_index;

while (PyList_GET_SIZE(MODULES_BY_INDEX(interp)) <= index) {

if (PyList_Append(MODULES_BY_INDEX(interp), Py_None) < 0) {

return -1;

}

}

return PyList_SetItem(MODULES_BY_INDEX(interp), index, Py_NewRef(module));

}

static int

_modules_by_index_clear_one(PyInterpreterState *interp, PyModuleDef *def)

{

Py_ssize_t index = def->m_base.m_index;

const char *err = _modules_by_index_check(interp, index);

if (err != NULL) {

Py_FatalError(err);

return -1;

}

return PyList_SetItem(MODULES_BY_INDEX(interp), index, Py_NewRef(Py_None));

}

PyObject*

PyState_FindModule(PyModuleDef* module)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

if (module->m_slots) {

return NULL;

}

return _modules_by_index_get(interp, module);

}

/* _PyState_AddModule() has been completely removed from the C-API

(and was removed from the limited API in 3.6). However, we're

playing it safe and keeping it around for any stable ABI extensions

built against 3.2-3.5. */

int

_PyState_AddModule(PyThreadState *tstate, PyObject* module, PyModuleDef* def)

{

if (!def) {

assert(_PyErr_Occurred(tstate));

return -1;

}

if (def->m_slots) {

_PyErr_SetString(tstate,

PyExc_SystemError,

"PyState_AddModule called on module with slots");

return -1;

}

return _modules_by_index_set(tstate->interp, def, module);

}

int

PyState_AddModule(PyObject* module, PyModuleDef* def)

{

if (!def) {

Py_FatalError("module definition is NULL");

return -1;

}

PyThreadState *tstate = _PyThreadState_GET();

if (def->m_slots) {

_PyErr_SetString(tstate,

PyExc_SystemError,

"PyState_AddModule called on module with slots");

return -1;

}

PyInterpreterState *interp = tstate->interp;

Py_ssize_t index = def->m_base.m_index;

if (MODULES_BY_INDEX(interp) &&

index < PyList_GET_SIZE(MODULES_BY_INDEX(interp)) &&

module == PyList_GET_ITEM(MODULES_BY_INDEX(interp), index))

{

_Py_FatalErrorFormat(__func__, "module %p already added", module);

return -1;

}

return _modules_by_index_set(interp, def, module);

}

int

PyState_RemoveModule(PyModuleDef* def)

{

PyThreadState *tstate = _PyThreadState_GET();

if (def->m_slots) {

_PyErr_SetString(tstate,

PyExc_SystemError,

"PyState_RemoveModule called on module with slots");

return -1;

}

return _modules_by_index_clear_one(tstate->interp, def);

}

// Used by finalize_modules()

void

_PyImport_ClearModulesByIndex(PyInterpreterState *interp)

{

if (!MODULES_BY_INDEX(interp)) {

return;

}

Py_ssize_t i;

for (i = 0; i < PyList_GET_SIZE(MODULES_BY_INDEX(interp)); i++) {

PyObject *m = PyList_GET_ITEM(MODULES_BY_INDEX(interp), i);

if (PyModule_Check(m)) {

/* cleanup the saved copy of module dicts */

PyModuleDef *md = PyModule_GetDef(m);

if (md) {

Py_CLEAR(md->m_base.m_copy);

}

}

}

/* Setting modules_by_index to NULL could be dangerous, so we

clear the list instead. */

if (PyList_SetSlice(MODULES_BY_INDEX(interp),

0, PyList_GET_SIZE(MODULES_BY_INDEX(interp)),

NULL)) {

PyErr_WriteUnraisable(MODULES_BY_INDEX(interp));

}

}

/*********************/

/* extension modules */

/*********************/

/*

It may help to have a big picture view of what happens

when an extension is loaded. This includes when it is imported

for the first time or via imp.load_dynamic().

Here's a summary, using imp.load_dynamic() as the starting point:

1. imp.load_dynamic() -> importlib._bootstrap._load()

2. _load(): acquire import lock

3. _load() -> importlib._bootstrap._load_unlocked()

4. _load_unlocked() -> importlib._bootstrap.module_from_spec()

5. module_from_spec() -> ExtensionFileLoader.create_module()

6. create_module() -> _imp.create_dynamic()

(see below)

7. module_from_spec() -> importlib._bootstrap._init_module_attrs()

8. _load_unlocked(): sys.modules[name] = module

9. _load_unlocked() -> ExtensionFileLoader.exec_module()

10. exec_module() -> _imp.exec_dynamic()

(see below)

11. _load(): release import lock

...for single-phase init modules, where m_size == -1:

(6). first time (not found in _PyRuntime.imports.extensions):

1. _imp_create_dynamic_impl() -> import_find_extension()

2. _imp_create_dynamic_impl() -> _PyImport_LoadDynamicModuleWithSpec()

3. _PyImport_LoadDynamicModuleWithSpec(): load <module init func>

4. _PyImport_LoadDynamicModuleWithSpec(): call <module init func>

5. <module init func> -> PyModule_Create() -> PyModule_Create2() -> PyModule_CreateInitialized()

6. PyModule_CreateInitialized() -> PyModule_New()

7. PyModule_CreateInitialized(): allocate mod->md_state

8. PyModule_CreateInitialized() -> PyModule_AddFunctions()

9. PyModule_CreateInitialized() -> PyModule_SetDocString()

10. PyModule_CreateInitialized(): set mod->md_def

11. <module init func>: initialize the module

12. _PyImport_LoadDynamicModuleWithSpec() -> _PyImport_CheckSubinterpIncompatibleExtensionAllowed()

13. _PyImport_LoadDynamicModuleWithSpec(): set def->m_base.m_init

14. _PyImport_LoadDynamicModuleWithSpec(): set __file__

15. _PyImport_LoadDynamicModuleWithSpec() -> _PyImport_FixupExtensionObject()

16. _PyImport_FixupExtensionObject(): add it to interp->imports.modules_by_index

17. _PyImport_FixupExtensionObject(): copy __dict__ into def->m_base.m_copy

18. _PyImport_FixupExtensionObject(): add it to _PyRuntime.imports.extensions

(6). subsequent times (found in _PyRuntime.imports.extensions):

1. _imp_create_dynamic_impl() -> import_find_extension()

2. import_find_extension() -> import_add_module()

3. if name in sys.modules: use that module

4. else:

1. import_add_module() -> PyModule_NewObject()

2. import_add_module(): set it on sys.modules

5. import_find_extension(): copy the "m_copy" dict into __dict__

6. _imp_create_dynamic_impl() -> _PyImport_CheckSubinterpIncompatibleExtensionAllowed()

(10). (every time):

1. noop

...for single-phase init modules, where m_size >= 0:

(6). not main interpreter and never loaded there - every time (not found in _PyRuntime.imports.extensions):

1-16. (same as for m_size == -1)

(6). main interpreter - first time (not found in _PyRuntime.imports.extensions):

1-16. (same as for m_size == -1)

17. _PyImport_FixupExtensionObject(): add it to _PyRuntime.imports.extensions

(6). previously loaded in main interpreter (found in _PyRuntime.imports.extensions):

1. _imp_create_dynamic_impl() -> import_find_extension()

2. import_find_extension(): call def->m_base.m_init

3. import_find_extension(): add the module to sys.modules

(10). every time:

1. noop

...for multi-phase init modules:

(6). every time:

1. _imp_create_dynamic_impl() -> import_find_extension() (not found)

2. _imp_create_dynamic_impl() -> _PyImport_LoadDynamicModuleWithSpec()

3. _PyImport_LoadDynamicModuleWithSpec(): load module init func

4. _PyImport_LoadDynamicModuleWithSpec(): call module init func

5. _PyImport_LoadDynamicModuleWithSpec() -> PyModule_FromDefAndSpec()

6. PyModule_FromDefAndSpec(): gather/check moduledef slots

7. if there's a Py_mod_create slot:

1. PyModule_FromDefAndSpec(): call its function

8. else:

1. PyModule_FromDefAndSpec() -> PyModule_NewObject()

9: PyModule_FromDefAndSpec(): set mod->md_def

10. PyModule_FromDefAndSpec() -> _add_methods_to_object()

11. PyModule_FromDefAndSpec() -> PyModule_SetDocString()

(10). every time:

1. _imp_exec_dynamic_impl() -> exec_builtin_or_dynamic()

2. if mod->md_state == NULL (including if m_size == 0):

1. exec_builtin_or_dynamic() -> PyModule_ExecDef()

2. PyModule_ExecDef(): allocate mod->md_state

3. if there's a Py_mod_exec slot:

1. PyModule_ExecDef(): call its function

*/

/* Make sure name is fully qualified.

This is a bit of a hack: when the shared library is loaded,

the module name is "package.module", but the module calls

PyModule_Create*() with just "module" for the name. The shared

library loader squirrels away the true name of the module in

_PyRuntime.imports.pkgcontext, and PyModule_Create*() will

substitute this (if the name actually matches).

*/

const char *

_PyImport_ResolveNameWithPackageContext(const char *name)

{

if (PKGCONTEXT != NULL) {

const char *p = strrchr(PKGCONTEXT, '.');

if (p != NULL && strcmp(name, p+1) == 0) {

name = PKGCONTEXT;

PKGCONTEXT = NULL;

}

}

return name;

}

const char *

_PyImport_SwapPackageContext(const char *newcontext)

{

const char *oldcontext = PKGCONTEXT;

PKGCONTEXT = newcontext;

return oldcontext;

}

#ifdef HAVE_DLOPEN

int

_PyImport_GetDLOpenFlags(PyInterpreterState *interp)

{

return DLOPENFLAGS(interp);

}

void

_PyImport_SetDLOpenFlags(PyInterpreterState *interp, int new_val)

{

DLOPENFLAGS(interp) = new_val;

}

#endif // HAVE_DLOPEN

/* Common implementation for _imp.exec_dynamic and _imp.exec_builtin */

static int

exec_builtin_or_dynamic(PyObject *mod) {

PyModuleDef *def;

void *state;

if (!PyModule_Check(mod)) {

return 0;

}

def = PyModule_GetDef(mod);

if (def == NULL) {

return 0;

}

state = PyModule_GetState(mod);

if (state) {

/* Already initialized; skip reload */

return 0;

}

return PyModule_ExecDef(mod, def);

}

static int clear_singlephase_extension(PyInterpreterState *interp,

PyObject *name, PyObject *filename);

// Currently, this is only used for testing.

// (See _testinternalcapi.clear_extension().)

int

_PyImport_ClearExtension(PyObject *name, PyObject *filename)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

/* Clearing a module's C globals is up to the module. */

if (clear_singlephase_extension(interp, name, filename) < 0) {

return -1;

}

// In the future we'll probably also make sure the extension's

// file handle (and DL handle) is closed (requires saving it).

return 0;

}

/*******************/

#if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)

#include <emscripten.h>

EM_JS(PyObject*, _PyImport_InitFunc_TrampolineCall, (PyModInitFunction func), {

return wasmTable.get(func)();

});

#endif // __EMSCRIPTEN__ && PY_CALL_TRAMPOLINE

/*****************************/

/* single-phase init modules */

/*****************************/

/*

We support a number of kinds of single-phase init builtin/extension modules:

* "basic"

* no module state (PyModuleDef.m_size == -1)

* does not support repeated init (we use PyModuleDef.m_base.m_copy)

* may have process-global state

* the module's def is cached in _PyRuntime.imports.extensions,

by (name, filename)

* "reinit"

* no module state (PyModuleDef.m_size == 0)

* supports repeated init (m_copy is never used)

* should not have any process-global state

* its def is never cached in _PyRuntime.imports.extensions

(except, currently, under the main interpreter, for some reason)

* "with state" (almost the same as reinit)

* has module state (PyModuleDef.m_size > 0)

* supports repeated init (m_copy is never used)

* should not have any process-global state

* its def is never cached in _PyRuntime.imports.extensions

(except, currently, under the main interpreter, for some reason)

There are also variants within those classes:

* two or more modules share a PyModuleDef

* a module's init func uses another module's PyModuleDef

* a module's init func calls another's module's init func

* a module's init "func" is actually a variable statically initialized

to another module's init func

* two or modules share "methods"

* a module's init func copies another module's PyModuleDef

(with a different name)

* (basic-only) two or modules share process-global state

In the first case, where modules share a PyModuleDef, the following

notable weirdness happens:

* the module's __name__ matches the def, not the requested name

* the last module (with the same def) to be imported for the first time wins

* returned by PyState_Find_Module() (via interp->modules_by_index)

* (non-basic-only) its init func is used when re-loading any of them

(via the def's m_init)

* (basic-only) the copy of its __dict__ is used when re-loading any of them

(via the def's m_copy)

However, the following happens as expected:

* a new module object (with its own __dict__) is created for each request

* the module's __spec__ has the requested name

* the loaded module is cached in sys.modules under the requested name

* the m_index field of the shared def is not changed,

so at least PyState_FindModule() will always look in the same place

For "basic" modules there are other quirks:

* (whether sharing a def or not) when loaded the first time,

m_copy is set before _init_module_attrs() is called

in importlib._bootstrap.module_from_spec(),

so when the module is re-loaded, the previous value

for __wpec__ (and others) is reset, possibly unexpectedly.

Generally, when multiple interpreters are involved, some of the above

gets even messier.

*/

static inline void

extensions_lock_acquire(void)

{

// XXX For now the GIL is sufficient.

}

static inline void

extensions_lock_release(void)

{

// XXX For now the GIL is sufficient.

}

/* Magic for extension modules (built-in as well as dynamically

loaded). To prevent initializing an extension module more than

once, we keep a static dictionary 'extensions' keyed by the tuple

(module name, module name) (for built-in modules) or by

(filename, module name) (for dynamically loaded modules), containing these

modules. A copy of the module's dictionary is stored by calling

_PyImport_FixupExtensionObject() immediately after the module initialization

function succeeds. A copy can be retrieved from there by calling

import_find_extension().

Modules which do support multiple initialization set their m_size

field to a non-negative number (indicating the size of the

module-specific state). They are still recorded in the extensions

dictionary, to avoid loading shared libraries twice.

*/

static void

_extensions_cache_init(void)

{

/* The runtime (i.e. main interpreter) must be initializing,

so we don't need to worry about the lock. */

_PyThreadState_InitDetached(&EXTENSIONS.main_tstate,

_PyInterpreterState_Main());

}

static PyModuleDef *

_extensions_cache_get(PyObject *filename, PyObject *name)

{

PyModuleDef *def = NULL;

extensions_lock_acquire();

PyObject *key = PyTuple_Pack(2, filename, name);

if (key == NULL) {

goto finally;

}

PyObject *extensions = EXTENSIONS.dict;

if (extensions == NULL) {

goto finally;

}

def = (PyModuleDef *)PyDict_GetItemWithError(extensions, key);

finally:

Py_XDECREF(key);

extensions_lock_release();

return def;

}

static int

_extensions_cache_set(PyObject *filename, PyObject *name, PyModuleDef *def)

{

int res = -1;

PyThreadState *oldts = NULL;

extensions_lock_acquire();

/* Swap to the main interpreter, if necessary. This matters if

the dict hasn't been created yet or if the item isn't in the

dict yet. In both cases we must ensure the relevant objects

are created using the main interpreter. */

PyThreadState *main_tstate = &EXTENSIONS.main_tstate;

PyInterpreterState *interp = _PyInterpreterState_GET();

if (!_Py_IsMainInterpreter(interp)) {

_PyThreadState_BindDetached(main_tstate);

oldts = _PyThreadState_Swap(interp->runtime, main_tstate);

assert(!_Py_IsMainInterpreter(oldts->interp));

/* Make sure the name and filename objects are owned

by the main interpreter. */

name = PyUnicode_InternFromString(PyUnicode_AsUTF8(name));

assert(name != NULL);

filename = PyUnicode_InternFromString(PyUnicode_AsUTF8(filename));

assert(filename != NULL);

}

PyObject *key = PyTuple_Pack(2, filename, name);

if (key == NULL) {

goto finally;

}

PyObject *extensions = EXTENSIONS.dict;

if (extensions == NULL) {

extensions = PyDict_New();

if (extensions == NULL) {

goto finally;

}

EXTENSIONS.dict = extensions;

}

PyModuleDef *actual = (PyModuleDef *)PyDict_GetItemWithError(extensions, key);

if (PyErr_Occurred()) {

goto finally;

}

else if (actual != NULL) {

/* We expect it to be static, so it must be the same pointer. */

assert(def == actual);

res = 0;

goto finally;

}

/* This might trigger a resize, which is why we must switch

to the main interpreter. */

res = PyDict_SetItem(extensions, key, (PyObject *)def);

if (res < 0) {

res = -1;

goto finally;

}

res = 0;

finally:

Py_XDECREF(key);

if (oldts != NULL) {

_PyThreadState_Swap(interp->runtime, oldts);

_PyThreadState_UnbindDetached(main_tstate);

Py_DECREF(name);

Py_DECREF(filename);

}

extensions_lock_release();

return res;

}

static int

_extensions_cache_delete(PyObject *filename, PyObject *name)

{

int res = -1;