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3933 lines (3383 loc) · 109 KB
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/* Module definition and import implementation */
#include "Python.h"
#include "pycore_hashtable.h" // _Py_hashtable_new_full()
#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_object.h" // _Py_SetImmortal()
#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)
{
PyThread_acquire_lock(EXTENSIONS.mutex, WAIT_LOCK);
LAST_MODULE_INDEX++;
Py_ssize_t index = LAST_MODULE_INDEX;
PyThread_release_lock(EXTENSIONS.mutex);
return 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.
Here's a summary, using importlib._boostrap._load() as a starting point.
1. 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).
*/
#ifdef HAVE_THREAD_LOCAL
_Py_thread_local const char *pkgcontext = NULL;
# undef PKGCONTEXT
# define PKGCONTEXT pkgcontext
#endif
const char *
_PyImport_ResolveNameWithPackageContext(const char *name)
{
#ifndef HAVE_THREAD_LOCAL
PyThread_acquire_lock(EXTENSIONS.mutex, WAIT_LOCK);
#endif
if (PKGCONTEXT != NULL) {
const char *p = strrchr(PKGCONTEXT, '.');
if (p != NULL && strcmp(name, p+1) == 0) {
name = PKGCONTEXT;
PKGCONTEXT = NULL;
}
}
#ifndef HAVE_THREAD_LOCAL
PyThread_release_lock(EXTENSIONS.mutex);
#endif
return name;
}
const char *
_PyImport_SwapPackageContext(const char *newcontext)
{
#ifndef HAVE_THREAD_LOCAL
PyThread_acquire_lock(EXTENSIONS.mutex, WAIT_LOCK);
#endif
const char *oldcontext = PKGCONTEXT;
PKGCONTEXT = newcontext;
#ifndef HAVE_THREAD_LOCAL
PyThread_release_lock(EXTENSIONS.mutex);
#endif
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)
{
PyThread_acquire_lock(_PyRuntime.imports.extensions.mutex, WAIT_LOCK);
}
static inline void
extensions_lock_release(void)
{
PyThread_release_lock(_PyRuntime.imports.extensions.mutex);
}
/* 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 *
hashtable_key_from_2_strings(PyObject *str1, PyObject *str2, const char sep)
{
const char *str1_data = _PyUnicode_AsUTF8NoNUL(str1);
const char *str2_data = _PyUnicode_AsUTF8NoNUL(str2);
if (str1_data == NULL || str2_data == NULL) {
return NULL;
}
Py_ssize_t str1_len = strlen(str1_data);
Py_ssize_t str2_len = strlen(str2_data);
/* Make sure sep and the NULL byte won't cause an overflow. */
assert(SIZE_MAX - str1_len - str2_len > 2);
size_t size = str1_len + 1 + str2_len + 1;
char *key = PyMem_RawMalloc(size);
if (key == NULL) {
PyErr_NoMemory();
return NULL;
}
strncpy(key, str1_data, str1_len);
key[str1_len] = sep;
strncpy(key + str1_len + 1, str2_data, str2_len + 1);
assert(strlen(key) == size - 1);
return key;
}
static Py_uhash_t
hashtable_hash_str(const void *key)
{
return _Py_HashBytes(key, strlen((const char *)key));
}
static int
hashtable_compare_str(const void *key1, const void *key2)
{
return strcmp((const char *)key1, (const char *)key2) == 0;
}
static void
hashtable_destroy_str(void *ptr)
{
PyMem_RawFree(ptr);
}
#define HTSEP ':'
static PyModuleDef *
_extensions_cache_get(PyObject *filename, PyObject *name)
{
PyModuleDef *def = NULL;
void *key = NULL;
extensions_lock_acquire();
if (EXTENSIONS.hashtable == NULL) {
goto finally;
}
key = hashtable_key_from_2_strings(filename, name, HTSEP);
if (key == NULL) {
goto finally;
}
_Py_hashtable_entry_t *entry = _Py_hashtable_get_entry(
EXTENSIONS.hashtable, key);
if (entry == NULL) {
goto finally;
}
def = (PyModuleDef *)entry->value;
finally:
extensions_lock_release();
if (key != NULL) {
PyMem_RawFree(key);
}
return def;
}
static int
_extensions_cache_set(PyObject *filename, PyObject *name, PyModuleDef *def)
{
int res = -1;
extensions_lock_acquire();
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