{{ message }}
forked from python/cpython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathimport.c
More file actions
4850 lines (4214 loc) · 143 KB
/
Copy pathimport.c
File metadata and controls
4850 lines (4214 loc) · 143 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* Module definition and import implementation */
#include "Python.h"
#include "pycore_audit.h" // _PySys_Audit()
#include "pycore_ceval.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_magic_number.h" // PYC_MAGIC_NUMBER_TOKEN
#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_DefaultRawFree()
#include "pycore_pystate.h" // _PyInterpreterState_GET()
#include "pycore_sysmodule.h" // _PySys_ClearAttrString()
#include "pycore_time.h" // _PyTime_AsMicroseconds()
#include "pycore_weakref.h" // _PyWeakref_GET_REF()
#include "marshal.h" // PyMarshal_ReadObjectFromString()
#include "pycore_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
/*[clinic input]
module _imp
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=9c332475d8686284]*/
#include "clinic/import.c.h"
#ifndef NDEBUG
static bool
is_interpreter_isolated(PyInterpreterState *interp)
{
return !_Py_IsMainInterpreter(interp)
&& !(interp->feature_flags & Py_RTFLAGS_USE_MAIN_OBMALLOC)
&& interp->ceval.own_gil;
}
#endif
/*******************************/
/* 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
#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)
{
_PyRecursiveMutex_Lock(&IMPORT_LOCK(interp));
}
void
_PyImport_ReleaseLock(PyInterpreterState *interp)
{
_PyRecursiveMutex_Unlock(&IMPORT_LOCK(interp));
}
void
_PyImport_ReInitLock(PyInterpreterState *interp)
{
// gh-126688: Thread id may change after fork() on some operating systems.
IMPORT_LOCK(interp).thread = PyThread_get_thread_ident_ex();
}
/***************/
/* 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);
}
static inline PyObject *
get_modules_dict(PyThreadState *tstate, bool fatal)
{
/* Technically, it would make sense to incref the dict,
* since sys.modules could be swapped out and decref'ed to 0
* before the caller is done using it. However, that is highly
* unlikely, especially since we can rely on a global lock
* (i.e. the GIL) for thread-safety. */
PyObject *modules = MODULES(tstate->interp);
if (modules == NULL) {
if (fatal) {
Py_FatalError("interpreter has no modules dictionary");
}
_PyErr_SetString(tstate, PyExc_RuntimeError,
"unable to get sys.modules");
return NULL;
}
return modules;
}
PyObject *
PyImport_GetModuleDict(void)
{
PyThreadState *tstate = _PyThreadState_GET();
return get_modules_dict(tstate, true);
}
int
_PyImport_SetModule(PyObject *name, PyObject *m)
{
PyThreadState *tstate = _PyThreadState_GET();
PyObject *modules = get_modules_dict(tstate, true);
return PyObject_SetItem(modules, name, m);
}
int
_PyImport_SetModuleString(const char *name, PyObject *m)
{
PyThreadState *tstate = _PyThreadState_GET();
PyObject *modules = get_modules_dict(tstate, true);
return PyMapping_SetItemString(modules, name, m);
}
static PyObject *
import_get_module(PyThreadState *tstate, PyObject *name)
{
PyObject *modules = get_modules_dict(tstate, false);
if (modules == NULL) {
return NULL;
}
PyObject *m;
Py_INCREF(modules);
(void)PyMapping_GetOptionalItem(modules, name, &m);
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.
*/
int rc = PyObject_GetOptionalAttr(mod, &_Py_ID(__spec__), &spec);
if (rc > 0) {
rc = _PyModuleSpec_IsInitializing(spec);
Py_DECREF(spec);
}
if (rc <= 0) {
return rc;
}
/* 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 = get_modules_dict(tstate, false);
if (modules == NULL) {
return NULL;
}
PyObject *m;
if (PyMapping_GetOptionalItem(modules, name, &m) < 0) {
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_AddModuleRef(const char *name)
{
PyObject *name_obj = PyUnicode_FromString(name);
if (name_obj == NULL) {
return NULL;
}
PyThreadState *tstate = _PyThreadState_GET();
PyObject *module = import_add_module(tstate, name_obj);
Py_DECREF(name_obj);
return module;
}
PyObject *
PyImport_AddModuleObject(PyObject *name)
{
PyThreadState *tstate = _PyThreadState_GET();
PyObject *mod = import_add_module(tstate, name);
if (!mod) {
return NULL;
}
// gh-86160: PyImport_AddModuleObject() returns a borrowed reference.
// Create a weak reference to produce a borrowed reference, since it can
// become NULL. sys.modules type can be different than dict and it is not
// guaranteed that it keeps a strong reference to the module. It can be a
// custom mapping with __getitem__() which returns a new object or removes
// returned object, or __setitem__ which does nothing. There is so much
// unknown. With weakref we can be sure that we get either a reference to
// live object or NULL.
//
// Use PyImport_AddModuleRef() to avoid these issues.
PyObject *ref = PyWeakref_NewRef(mod, NULL);
Py_DECREF(mod);
if (ref == NULL) {
return NULL;
}
mod = _PyWeakref_GET_REF(ref);
Py_DECREF(ref);
Py_XDECREF(mod);
if (mod == NULL && !PyErr_Occurred()) {
PyErr_SetString(PyExc_RuntimeError,
"sys.modules does not hold a strong reference "
"to the module");
}
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 = get_modules_dict(tstate, true);
if (PyDict_CheckExact(modules)) {
// Error is reported to the caller
(void)PyDict_Pop(modules, name, NULL);
}
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)
{
return _Py_atomic_add_ssize(&LAST_MODULE_INDEX, 1) + 1;
}
#ifndef NDEBUG
struct extensions_cache_value;
static struct extensions_cache_value * _find_cached_def(PyModuleDef *);
static Py_ssize_t _get_cached_module_index(struct extensions_cache_value *);
#endif
static Py_ssize_t
_get_module_index_from_def(PyModuleDef *def)
{
Py_ssize_t index = def->m_base.m_index;
#ifndef NDEBUG
struct extensions_cache_value *cached = _find_cached_def(def);
assert(cached == NULL || index == _get_cached_module_index(cached));
#endif
return index;
}
static void
_set_module_index(PyModuleDef *def, Py_ssize_t index)
{
assert(index > 0);
if (index == def->m_base.m_index) {
/* There's nothing to do. */
}
else if (def->m_base.m_index == 0) {
/* It should have been initialized by PyModuleDef_Init().
* We assert here to catch this in dev, but keep going otherwise. */
assert(def->m_base.m_index != 0);
def->m_base.m_index = index;
}
else {
/* It was already set for a different module.
* We replace the old value. */
assert(def->m_base.m_index > 0);
def->m_base.m_index = 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, Py_ssize_t 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,
Py_ssize_t index, PyObject *module)
{
assert(index > 0);
if (MODULES_BY_INDEX(interp) == NULL) {
MODULES_BY_INDEX(interp) = PyList_New(0);
if (MODULES_BY_INDEX(interp) == NULL) {
return -1;
}
}
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, Py_ssize_t 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;
}
Py_ssize_t index = _get_module_index_from_def(module);
return _modules_by_index_get(interp, index);
}
/* _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;
}
assert(def->m_slots == NULL);
Py_ssize_t index = _get_module_index_from_def(def);
return _modules_by_index_set(tstate->interp, index, 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 = _get_module_index_from_def(def);
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;
}
assert(def->m_slots == NULL);
return _modules_by_index_set(interp, index, 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;
}
Py_ssize_t index = _get_module_index_from_def(def);
return _modules_by_index_clear_one(tstate->interp, index);
}
// 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) {
// XXX Do this more carefully. The dict might be owned
// by another interpreter.
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_FormatUnraisable("Exception ignored while "
"clearing interpreters module list");
}
}
/*********************/
/* 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._bootstrap._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):
A. _imp_create_dynamic_impl() -> import_find_extension()
B. _imp_create_dynamic_impl() -> _PyImport_GetModInitFunc()
C. _PyImport_GetModInitFunc(): load <module init func>
D. _imp_create_dynamic_impl() -> import_run_extension()
E. import_run_extension() -> _PyImport_RunModInitFunc()
F. _PyImport_RunModInitFunc(): call <module init func>
G. <module init func> -> PyModule_Create() -> PyModule_Create2()
-> PyModule_CreateInitialized()
H. PyModule_CreateInitialized() -> PyModule_New()
I. PyModule_CreateInitialized(): allocate mod->md_state
J. PyModule_CreateInitialized() -> PyModule_AddFunctions()
K. PyModule_CreateInitialized() -> PyModule_SetDocString()
L. PyModule_CreateInitialized(): set mod->md_def
M. <module init func>: initialize the module, etc.
N. import_run_extension()
-> _PyImport_CheckSubinterpIncompatibleExtensionAllowed()
O. import_run_extension(): set __file__
P. import_run_extension() -> update_global_state_for_extension()
Q. update_global_state_for_extension():
copy __dict__ into def->m_base.m_copy
R. update_global_state_for_extension():
add it to _PyRuntime.imports.extensions
S. import_run_extension() -> finish_singlephase_extension()
T. finish_singlephase_extension():
add it to interp->imports.modules_by_index
U. finish_singlephase_extension(): add it to sys.modules
Step (Q) is skipped for core modules (sys/builtins).
(6). subsequent times (found in _PyRuntime.imports.extensions):
A. _imp_create_dynamic_impl() -> import_find_extension()
B. import_find_extension() -> reload_singlephase_extension()
C. reload_singlephase_extension()
-> _PyImport_CheckSubinterpIncompatibleExtensionAllowed()
D. reload_singlephase_extension() -> import_add_module()
E. if name in sys.modules: use that module
F. else:
1. import_add_module() -> PyModule_NewObject()
2. import_add_module(): set it on sys.modules
G. reload_singlephase_extension(): copy the "m_copy" dict into __dict__
H. reload_singlephase_extension(): add to modules_by_index
(10). (every time):
A. 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):
A-P. (same as for m_size == -1)
Q. _PyImport_RunModInitFunc(): set def->m_base.m_init
R. (skipped)
S-U. (same as for m_size == -1)
(6). main interpreter - first time (not found in _PyRuntime.imports.extensions):
A-P. (same as for m_size == -1)
Q. _PyImport_RunModInitFunc(): set def->m_base.m_init
R-U. (same as for m_size == -1)
(6). subsequent times (found in _PyRuntime.imports.extensions):
A. _imp_create_dynamic_impl() -> import_find_extension()
B. import_find_extension() -> reload_singlephase_extension()
C. reload_singlephase_extension()
-> _PyImport_CheckSubinterpIncompatibleExtensionAllowed()
D. reload_singlephase_extension(): call def->m_base.m_init (see above)
E. reload_singlephase_extension(): add the module to sys.modules
F. reload_singlephase_extension(): add to modules_by_index
(10). every time:
A. noop
...for multi-phase init modules:
(6). every time:
A. _imp_create_dynamic_impl() -> import_find_extension() (not found)
B. _imp_create_dynamic_impl() -> _PyImport_GetModInitFunc()
C. _PyImport_GetModInitFunc(): load <module init func>
D. _imp_create_dynamic_impl() -> import_run_extension()
E. import_run_extension() -> _PyImport_RunModInitFunc()
F. _PyImport_RunModInitFunc(): call <module init func>
G. import_run_extension() -> PyModule_FromDefAndSpec()
H. PyModule_FromDefAndSpec(): gather/check moduledef slots
I. if there's a Py_mod_create slot:
1. PyModule_FromDefAndSpec(): call its function
J. else:
1. PyModule_FromDefAndSpec() -> PyModule_NewObject()
K: PyModule_FromDefAndSpec(): set mod->md_def
L. PyModule_FromDefAndSpec() -> _add_methods_to_object()
M. PyModule_FromDefAndSpec() -> PyModule_SetDocString()
(10). every time:
A. _imp_exec_dynamic_impl() -> exec_builtin_or_dynamic()
B. 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
PyMutex_Lock(&EXTENSIONS.mutex);
#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
PyMutex_Unlock(&EXTENSIONS.mutex);
#endif
return name;
}
const char *
_PyImport_SwapPackageContext(const char *newcontext)
{
#ifndef HAVE_THREAD_LOCAL
PyMutex_Lock(&EXTENSIONS.mutex);
#endif
const char *oldcontext = PKGCONTEXT;
PKGCONTEXT = newcontext;
#ifndef HAVE_THREAD_LOCAL
PyMutex_Unlock(&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().)
// If adding another use, be careful about modules that import themselves
// recursively (see gh-123880).
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;
}
/*****************************/
/* 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)
{
PyMutex_Lock(&_PyRuntime.imports.extensions.mutex);
}
static inline void
extensions_lock_release(void)
{
PyMutex_Unlock(&_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
fix_up_extension() 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.
*/
typedef struct cached_m_dict {
/* A shallow copy of the original module's __dict__. */
PyObject *copied;
/* The interpreter that owns the copy. */
int64_t interpid;
} *cached_m_dict_t;
struct extensions_cache_value {
PyModuleDef *def;
/* The function used to re-initialize the module.
This is only set for legacy (single-phase init) extension modules
and only used for those that support multiple initializations
(m_size >= 0).
It is set by update_global_state_for_extension(). */
PyModInitFunction m_init;
/* The module's index into its interpreter's modules_by_index cache.
This is set for all extension modules but only used for legacy ones.
(See PyInterpreterState.modules_by_index for more info.) */
Py_ssize_t m_index;
/* A copy of the module's __dict__ after the first time it was loaded.
This is only set/used for legacy modules that do not support
multiple initializations.
It is set exclusively by fixup_cached_def(). */
cached_m_dict_t m_dict;
struct cached_m_dict _m_dict;
_Py_ext_module_origin origin;
#ifdef Py_GIL_DISABLED
/* The module's md_gil slot, for legacy modules that are reinitialized from
m_dict rather than calling their initialization function again. */
void *md_gil;
#endif
};
static struct extensions_cache_value *
alloc_extensions_cache_value(void)
{
struct extensions_cache_value *value
= PyMem_RawMalloc(sizeof(struct extensions_cache_value));
if (value == NULL) {
PyErr_NoMemory();
return NULL;
}
*value = (struct extensions_cache_value){0};
return value;
}
static void
free_extensions_cache_value(struct extensions_cache_value *value)
{
PyMem_RawFree(value);
}
You can’t perform that action at this time.