summaryrefslogtreecommitdiffstats
path: root/Modules/getpath.c
blob: 3b926cac0d3f24ec2ebf30006ececad6da098500 (plain)
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
/* Return the initial module search path. */

#include "Python.h"
#include "pycore_fileutils.h"     // _Py_abspath()
#include "pycore_initconfig.h"    // _PyStatus_EXCEPTION()
#include "pycore_pathconfig.h"    // _PyPathConfig_ReadGlobal()
#include "pycore_pyerrors.h"      // _PyErr_WriteUnraisableMsg()
#include "pycore_pymem.h"         // _PyMem_RawWcsdup()

#include "marshal.h"              // PyMarshal_ReadObjectFromString
#include "osdefs.h"               // DELIM
#include <wchar.h>

#ifdef MS_WINDOWS
#  include <windows.h>            // GetFullPathNameW(), MAX_PATH
#  include <pathcch.h>
#endif

#ifdef __APPLE__
#  include <mach-o/dyld.h>
#endif

/* Reference the precompiled getpath.py */
#include "../Python/frozen_modules/getpath.h"

#if (!defined(PREFIX) || !defined(EXEC_PREFIX) \
        || !defined(VERSION) || !defined(VPATH) \
        || !defined(PLATLIBDIR))
#error "PREFIX, EXEC_PREFIX, VERSION, VPATH and PLATLIBDIR macros must be defined"
#endif

#if !defined(PYTHONPATH)
#define PYTHONPATH NULL
#endif

#if !defined(PYDEBUGEXT)
#define PYDEBUGEXT NULL
#endif

#if !defined(PYWINVER)
#ifdef MS_DLL_ID
#define PYWINVER MS_DLL_ID
#else
#define PYWINVER NULL
#endif
#endif

#if !defined(EXE_SUFFIX)
#if defined(MS_WINDOWS) || defined(__CYGWIN__) || defined(__MINGW32__)
#define EXE_SUFFIX L".exe"
#else
#define EXE_SUFFIX NULL
#endif
#endif


/* HELPER FUNCTIONS for getpath.py */

static PyObject *
getpath_abspath(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    wchar_t *path;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
    Py_ssize_t len;
    path = PyUnicode_AsWideCharString(pathobj, &len);
    if (path) {
        wchar_t *abs;
        if (_Py_abspath((const wchar_t *)_Py_normpath(path, -1), &abs) == 0 && abs) {
            r = PyUnicode_FromWideChar(abs, -1);
            PyMem_RawFree((void *)abs);
        } else {
            PyErr_SetString(PyExc_OSError, "failed to make path absolute");
        }
        PyMem_Free((void *)path);
    }
    return r;
}


static PyObject *
getpath_basename(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *path;
    if (!PyArg_ParseTuple(args, "U", &path)) {
        return NULL;
    }
    Py_ssize_t end = PyUnicode_GET_LENGTH(path);
    Py_ssize_t pos = PyUnicode_FindChar(path, SEP, 0, end, -1);
    if (pos < 0) {
        return Py_NewRef(path);
    }
    return PyUnicode_Substring(path, pos + 1, end);
}


static PyObject *
getpath_dirname(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *path;
    if (!PyArg_ParseTuple(args, "U", &path)) {
        return NULL;
    }
    Py_ssize_t end = PyUnicode_GET_LENGTH(path);
    Py_ssize_t pos = PyUnicode_FindChar(path, SEP, 0, end, -1);
    if (pos < 0) {
        return PyUnicode_FromStringAndSize(NULL, 0);
    }
    return PyUnicode_Substring(path, 0, pos);
}


static PyObject *
getpath_isabs(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    const wchar_t *path;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
    path = PyUnicode_AsWideCharString(pathobj, NULL);
    if (path) {
        r = _Py_isabs(path) ? Py_True : Py_False;
        PyMem_Free((void *)path);
    }
    return Py_XNewRef(r);
}


static PyObject *
getpath_hassuffix(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    PyObject *suffixobj;
    const wchar_t *path;
    const wchar_t *suffix;
    if (!PyArg_ParseTuple(args, "UU", &pathobj, &suffixobj)) {
        return NULL;
    }
    Py_ssize_t len, suffixLen;
    path = PyUnicode_AsWideCharString(pathobj, &len);
    if (path) {
        suffix = PyUnicode_AsWideCharString(suffixobj, &suffixLen);
        if (suffix) {
            if (suffixLen > len ||
#ifdef MS_WINDOWS
                wcsicmp(&path[len - suffixLen], suffix) != 0
#else
                wcscmp(&path[len - suffixLen], suffix) != 0
#endif
            ) {
                r = Py_NewRef(Py_False);
            } else {
                r = Py_NewRef(Py_True);
            }
            PyMem_Free((void *)suffix);
        }
        PyMem_Free((void *)path);
    }
    return r;
}


static PyObject *
getpath_isdir(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    const wchar_t *path;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
    path = PyUnicode_AsWideCharString(pathobj, NULL);
    if (path) {
#ifdef MS_WINDOWS
        DWORD attr = GetFileAttributesW(path);
        r = (attr != INVALID_FILE_ATTRIBUTES) &&
            (attr & FILE_ATTRIBUTE_DIRECTORY) ? Py_True : Py_False;
#else
        struct stat st;
        r = (_Py_wstat(path, &st) == 0) && S_ISDIR(st.st_mode) ? Py_True : Py_False;
#endif
        PyMem_Free((void *)path);
    }
    return Py_XNewRef(r);
}


static PyObject *
getpath_isfile(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    const wchar_t *path;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
    path = PyUnicode_AsWideCharString(pathobj, NULL);
    if (path) {
#ifdef MS_WINDOWS
        DWORD attr = GetFileAttributesW(path);
        r = (attr != INVALID_FILE_ATTRIBUTES) &&
            !(attr & FILE_ATTRIBUTE_DIRECTORY) ? Py_True : Py_False;
#else
        struct stat st;
        r = (_Py_wstat(path, &st) == 0) && S_ISREG(st.st_mode) ? Py_True : Py_False;
#endif
        PyMem_Free((void *)path);
    }
    return Py_XNewRef(r);
}


static PyObject *
getpath_isxfile(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    const wchar_t *path;
    Py_ssize_t cchPath;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
    path = PyUnicode_AsWideCharString(pathobj, &cchPath);
    if (path) {
#ifdef MS_WINDOWS
        DWORD attr = GetFileAttributesW(path);
        r = (attr != INVALID_FILE_ATTRIBUTES) &&
            !(attr & FILE_ATTRIBUTE_DIRECTORY) &&
            (cchPath >= 4) &&
            (CompareStringOrdinal(path + cchPath - 4, -1, L".exe", -1, 1 /* ignore case */) == CSTR_EQUAL)
            ? Py_True : Py_False;
#else
        struct stat st;
        r = (_Py_wstat(path, &st) == 0) &&
            S_ISREG(st.st_mode) &&
            (st.st_mode & 0111)
            ? Py_True : Py_False;
#endif
        PyMem_Free((void *)path);
    }
    return Py_XNewRef(r);
}


static PyObject *
getpath_joinpath(PyObject *Py_UNUSED(self), PyObject *args)
{
    if (!PyTuple_Check(args)) {
        PyErr_SetString(PyExc_TypeError, "requires tuple of arguments");
        return NULL;
    }
    Py_ssize_t n = PyTuple_GET_SIZE(args);
    if (n == 0) {
        return PyUnicode_FromStringAndSize(NULL, 0);
    }
    /* Convert all parts to wchar and accumulate max final length */
    wchar_t **parts = (wchar_t **)PyMem_Malloc(n * sizeof(wchar_t *));
    memset(parts, 0, n * sizeof(wchar_t *));
    Py_ssize_t cchFinal = 0;
    Py_ssize_t first = 0;

    for (Py_ssize_t i = 0; i < n; ++i) {
        PyObject *s = PyTuple_GET_ITEM(args, i);
        Py_ssize_t cch;
        if (s == Py_None) {
            cch = 0;
        } else if (PyUnicode_Check(s)) {
            parts[i] = PyUnicode_AsWideCharString(s, &cch);
            if (!parts[i]) {
                cchFinal = -1;
                break;
            }
            if (_Py_isabs(parts[i])) {
                first = i;
            }
        } else {
            PyErr_SetString(PyExc_TypeError, "all arguments to joinpath() must be str or None");
            cchFinal = -1;
            break;
        }
        cchFinal += cch + 1;
    }

    wchar_t *final = cchFinal > 0 ? (wchar_t *)PyMem_Malloc(cchFinal * sizeof(wchar_t)) : NULL;
    if (!final) {
        for (Py_ssize_t i = 0; i < n; ++i) {
            PyMem_Free(parts[i]);
        }
        PyMem_Free(parts);
        if (cchFinal) {
            PyErr_NoMemory();
            return NULL;
        }
        return PyUnicode_FromStringAndSize(NULL, 0);
    }

    final[0] = '\0';
    /* Now join all the paths. The final result should be shorter than the buffer */
    for (Py_ssize_t i = 0; i < n; ++i) {
        if (!parts[i]) {
            continue;
        }
        if (i >= first && final) {
            if (!final[0]) {
                /* final is definitely long enough to fit any individual part */
                wcscpy(final, parts[i]);
            } else if (_Py_add_relfile(final, parts[i], cchFinal) < 0) {
                /* if we fail, keep iterating to free memory, but stop adding parts */
                PyMem_Free(final);
                final = NULL;
            }
        }
        PyMem_Free(parts[i]);
    }
    PyMem_Free(parts);
    if (!final) {
        PyErr_SetString(PyExc_SystemError, "failed to join paths");
        return NULL;
    }
    PyObject *r = PyUnicode_FromWideChar(_Py_normpath(final, -1), -1);
    PyMem_Free(final);
    return r;
}


static PyObject *
getpath_readlines(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *r = NULL;
    PyObject *pathobj;
    const wchar_t *path;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
    path = PyUnicode_AsWideCharString(pathobj, NULL);
    if (!path) {
        return NULL;
    }
    FILE *fp = _Py_wfopen(path, L"rb");
    if (!fp) {
        PyErr_SetFromErrno(PyExc_OSError);
        PyMem_Free((void *)path);
        return NULL;
    }
    PyMem_Free((void *)path);

    r = PyList_New(0);
    if (!r) {
        fclose(fp);
        return NULL;
    }
    const size_t MAX_FILE = 32 * 1024;
    char *buffer = (char *)PyMem_Malloc(MAX_FILE);
    if (!buffer) {
        Py_DECREF(r);
        fclose(fp);
        return NULL;
    }

    size_t cb = fread(buffer, 1, MAX_FILE, fp);
    fclose(fp);
    if (!cb) {
        return r;
    }
    if (cb >= MAX_FILE) {
        Py_DECREF(r);
        PyErr_SetString(PyExc_MemoryError,
            "cannot read file larger than 32KB during initialization");
        return NULL;
    }
    buffer[cb] = '\0';

    size_t len;
    wchar_t *wbuffer = _Py_DecodeUTF8_surrogateescape(buffer, cb, &len);
    PyMem_Free((void *)buffer);
    if (!wbuffer) {
        Py_DECREF(r);
        PyErr_NoMemory();
        return NULL;
    }

    wchar_t *p1 = wbuffer;
    wchar_t *p2 = p1;
    while ((p2 = wcschr(p1, L'\n')) != NULL) {
        Py_ssize_t cb = p2 - p1;
        while (cb >= 0 && (p1[cb] == L'\n' || p1[cb] == L'\r')) {
            --cb;
        }
        PyObject *u = PyUnicode_FromWideChar(p1, cb >= 0 ? cb + 1 : 0);
        if (!u || PyList_Append(r, u) < 0) {
            Py_XDECREF(u);
            Py_CLEAR(r);
            break;
        }
        Py_DECREF(u);
        p1 = p2 + 1;
    }
    if (r && p1 && *p1) {
        PyObject *u = PyUnicode_FromWideChar(p1, -1);
        if (!u || PyList_Append(r, u) < 0) {
            Py_CLEAR(r);
        }
        Py_XDECREF(u);
    }
    PyMem_RawFree(wbuffer);
    return r;
}


static PyObject *
getpath_realpath(PyObject *Py_UNUSED(self) , PyObject *args)
{
    PyObject *pathobj;
    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
        return NULL;
    }
#if defined(HAVE_READLINK)
    /* This readlink calculation only resolves a symlinked file, and
       does not resolve any path segments. This is consistent with
       prior releases, however, the realpath implementation below is
       potentially correct in more cases. */
    PyObject *r = NULL;
    int nlink = 0;
    wchar_t *path = PyUnicode_AsWideCharString(pathobj, NULL);
    if (!path) {
        goto done;
    }
    wchar_t *path2 = _PyMem_RawWcsdup(path);
    PyMem_Free((void *)path);
    path = path2;
    while (path) {
        wchar_t resolved[MAXPATHLEN + 1];
        int linklen = _Py_wreadlink(path, resolved, Py_ARRAY_LENGTH(resolved));
        if (linklen == -1) {
            r = PyUnicode_FromWideChar(path, -1);
            break;
        }
        if (_Py_isabs(resolved)) {
            PyMem_RawFree((void *)path);
            path = _PyMem_RawWcsdup(resolved);
        } else {
            wchar_t *s = wcsrchr(path, SEP);
            if (s) {
                *s = L'\0';
            }
            path2 = _Py_join_relfile(path, resolved);
            if (path2) {
                path2 = _Py_normpath(path2, -1);
            }
            PyMem_RawFree((void *)path);
            path = path2;
        }
        nlink++;
        /* 40 is the Linux kernel 4.2 limit */
        if (nlink >= 40) {
            PyErr_SetString(PyExc_OSError, "maximum number of symbolic links reached");
            break;
        }
    }
    if (!path) {
        PyErr_NoMemory();
    }
done:
    PyMem_RawFree((void *)path);
    return r;

#elif defined(HAVE_REALPATH)
    PyObject *r = NULL;
    struct stat st;
    const char *narrow = NULL;
    wchar_t *path = PyUnicode_AsWideCharString(pathobj, NULL);
    if (!path) {
        goto done;
    }
    narrow = Py_EncodeLocale(path, NULL);
    if (!narrow) {
        PyErr_NoMemory();
        goto done;
    }
    if (lstat(narrow, &st)) {
        PyErr_SetFromErrno(PyExc_OSError);
        goto done;
    }
    if (!S_ISLNK(st.st_mode)) {
        r = Py_NewRef(pathobj);
        goto done;
    }
    wchar_t resolved[MAXPATHLEN+1];
    if (_Py_wrealpath(path, resolved, MAXPATHLEN) == NULL) {
        PyErr_SetFromErrno(PyExc_OSError);
    } else {
        r = PyUnicode_FromWideChar(resolved, -1);
    }
done:
    PyMem_Free((void *)path);
    PyMem_Free((void *)narrow);
    return r;
#endif

    return Py_NewRef(pathobj);
}


static PyMethodDef getpath_methods[] = {
    {"abspath", getpath_abspath, METH_VARARGS, NULL},
    {"basename", getpath_basename, METH_VARARGS, NULL},
    {"dirname", getpath_dirname, METH_VARARGS, NULL},
    {"hassuffix", getpath_hassuffix, METH_VARARGS, NULL},
    {"isabs", getpath_isabs, METH_VARARGS, NULL},
    {"isdir", getpath_isdir, METH_VARARGS, NULL},
    {"isfile", getpath_isfile, METH_VARARGS, NULL},
    {"isxfile", getpath_isxfile, METH_VARARGS, NULL},
    {"joinpath", getpath_joinpath, METH_VARARGS, NULL},
    {"readlines", getpath_readlines, METH_VARARGS, NULL},
    {"realpath", getpath_realpath, METH_VARARGS, NULL},
    {NULL, NULL, 0, NULL}
};


/* Two implementations of warn() to use depending on whether warnings
   are enabled or not. */

static PyObject *
getpath_warn(PyObject *Py_UNUSED(self), PyObject *args)
{
    PyObject *msgobj;
    if (!PyArg_ParseTuple(args, "U", &msgobj)) {
        return NULL;
    }
    fprintf(stderr, "%s\n", PyUnicode_AsUTF8(msgobj));
    Py_RETURN_NONE;
}


static PyObject *
getpath_nowarn(PyObject *Py_UNUSED(self), PyObject *args)
{
    Py_RETURN_NONE;
}


static PyMethodDef getpath_warn_method = {"warn", getpath_warn, METH_VARARGS, NULL};
static PyMethodDef getpath_nowarn_method = {"warn", getpath_nowarn, METH_VARARGS, NULL};

/* Add the helper functions to the dict */
static int
funcs_to_dict(PyObject *dict, int warnings)
{
    for (PyMethodDef *m = getpath_methods; m->ml_name; ++m) {
        PyObject *f = PyCFunction_NewEx(m, NULL, NULL);
        if (!f) {
            return 0;
        }
        if (PyDict_SetItemString(dict, m->ml_name, f) < 0) {
            Py_DECREF(f);
            return 0;
        }
        Py_DECREF(f);
    }
    PyMethodDef *m2 = warnings ? &getpath_warn_method : &getpath_nowarn_method;
    PyObject *f = PyCFunction_NewEx(m2, NULL, NULL);
    if (!f) {
        return 0;
    }
    if (PyDict_SetItemString(dict, m2->ml_name, f) < 0) {
        Py_DECREF(f);
        return 0;
    }
    Py_DECREF(f);
    return 1;
}


/* Add a wide-character string constant to the dict */
static int
wchar_to_dict(PyObject *dict, const char *key, const wchar_t *s)
{
    PyObject *u;
    int r;
    if (s && s[0]) {
        u = PyUnicode_FromWideChar(s, -1);
        if (!u) {
            return 0;
        }
    } else {
        u = Py_NewRef(Py_None);
    }
    r = PyDict_SetItemString(dict, key, u) == 0;
    Py_DECREF(u);
    return r;
}


/* Add a narrow string constant to the dict, using default locale decoding */
static int
decode_to_dict(PyObject *dict, const char *key, const char *s)
{
    PyObject *u = NULL;
    int r;
    if (s && s[0]) {
        size_t len;
        const wchar_t *w = Py_DecodeLocale(s, &len);
        if (w) {
            u = PyUnicode_FromWideChar(w, len);
            PyMem_RawFree((void *)w);
        }
        if (!u) {
            return 0;
        }
    } else {
        u = Py_NewRef(Py_None);
    }
    r = PyDict_SetItemString(dict, key, u) == 0;
    Py_DECREF(u);
    return r;
}

/* Add an environment variable to the dict, optionally clearing it afterwards */
static int
env_to_dict(PyObject *dict, const char *key, int and_clear)
{
    PyObject *u = NULL;
    int r = 0;
    assert(strncmp(key, "ENV_", 4) == 0);
    assert(strlen(key) < 64);
#ifdef MS_WINDOWS
    wchar_t wkey[64];
    // Quick convert to wchar_t, since we know key is ASCII
    wchar_t *wp = wkey;
    for (const char *p = &key[4]; *p; ++p) {
        assert(*p < 128);
        *wp++ = *p;
    }
    *wp = L'\0';
    const wchar_t *v = _wgetenv(wkey);
    if (v) {
        u = PyUnicode_FromWideChar(v, -1);
        if (!u) {
            PyErr_Clear();
        }
    }
#else
    const char *v = getenv(&key[4]);
    if (v) {
        size_t len;
        const wchar_t *w = Py_DecodeLocale(v, &len);
        if (w) {
            u = PyUnicode_FromWideChar(w, len);
            if (!u) {
                PyErr_Clear();
            }
            PyMem_RawFree((void *)w);
        }
    }
#endif
    if (u) {
        r = PyDict_SetItemString(dict, key, u) == 0;
        Py_DECREF(u);
    } else {
        r = PyDict_SetItemString(dict, key, Py_None) == 0;
    }
    if (r && and_clear) {
#ifdef MS_WINDOWS
        _wputenv_s(wkey, L"");
#else
        unsetenv(&key[4]);
#endif
    }
    return r;
}


/* Add an integer constant to the dict */
static int
int_to_dict(PyObject *dict, const char *key, int v)
{
    PyObject *o;
    int r;
    o = PyLong_FromLong(v);
    if (!o) {
        return 0;
    }
    r = PyDict_SetItemString(dict, key, o) == 0;
    Py_DECREF(o);
    return r;
}


#ifdef MS_WINDOWS
static int
winmodule_to_dict(PyObject *dict, const char *key, HMODULE mod)
{
    wchar_t *buffer = NULL;
    for (DWORD cch = 256; buffer == NULL && cch < (1024 * 1024); cch *= 2) {
        buffer = (wchar_t*)PyMem_RawMalloc(cch * sizeof(wchar_t));
        if (buffer) {
            if (GetModuleFileNameW(mod, buffer, cch) == cch) {
                PyMem_RawFree(buffer);
                buffer = NULL;
            }
        }
    }
    int r = wchar_to_dict(dict, key, buffer);
    PyMem_RawFree(buffer);
    return r;
}
#endif


/* Add the current executable's path to the dict */
static int
progname_to_dict(PyObject *dict, const char *key)
{
#ifdef MS_WINDOWS
    return winmodule_to_dict(dict, key, NULL);
#elif defined(__APPLE__)
    char *path;
    uint32_t pathLen = 256;
    while (pathLen) {
        path = PyMem_RawMalloc((pathLen + 1) * sizeof(char));
        if (!path) {
            return 0;
        }
        if (_NSGetExecutablePath(path, &pathLen) != 0) {
            PyMem_RawFree(path);
            continue;
        }
        // Only keep if the path is absolute
        if (path[0] == SEP) {
            int r = decode_to_dict(dict, key, path);
            PyMem_RawFree(path);
            return r;
        }
        // Fall back and store None
        PyMem_RawFree(path);
        break;
    }
#endif
    return PyDict_SetItemString(dict, key, Py_None) == 0;
}


/* Add the runtime library's path to the dict */
static int
library_to_dict(PyObject *dict, const char *key)
{
#ifdef MS_WINDOWS
#ifdef Py_ENABLE_SHARED
    extern HMODULE PyWin_DLLhModule;
    if (PyWin_DLLhModule) {
        return winmodule_to_dict(dict, key, PyWin_DLLhModule);
    }
#endif
#elif defined(WITH_NEXT_FRAMEWORK)
    static char modPath[MAXPATHLEN + 1];
    static int modPathInitialized = -1;
    if (modPathInitialized < 0) {
        modPathInitialized = 0;

        /* On Mac OS X we have a special case if we're running from a framework.
           This is because the python home should be set relative to the library,
           which is in the framework, not relative to the executable, which may
           be outside of the framework. Except when we're in the build
           directory... */
        NSSymbol symbol = NSLookupAndBindSymbol("_Py_Initialize");
        if (symbol != NULL) {
            NSModule pythonModule = NSModuleForSymbol(symbol);
            if (pythonModule != NULL) {
                /* Use dylib functions to find out where the framework was loaded from */
                const char *path = NSLibraryNameForModule(pythonModule);
                if (path) {
                    strncpy(modPath, path, MAXPATHLEN);
                    modPathInitialized = 1;
                }
            }
        }
    }
    if (modPathInitialized > 0) {
        return decode_to_dict(dict, key, modPath);
    }
#endif
    return PyDict_SetItemString(dict, key, Py_None) == 0;
}


PyObject *
_Py_Get_Getpath_CodeObject(void)
{
    return PyMarshal_ReadObjectFromString(
        (const char*)_Py_M__getpath, sizeof(_Py_M__getpath));
}


/* Perform the actual path calculation.

   When compute_path_config is 0, this only reads any initialised path
   config values into the PyConfig struct. For example, Py_SetHome() or
   Py_SetPath(). The only error should be due to failed memory allocation.

   When compute_path_config is 1, full path calculation is performed.
   The GIL must be held, and there may be filesystem access, side
   effects, and potential unraisable errors that are reported directly
   to stderr.

   Calling this function multiple times on the same PyConfig is only
   safe because already-configured values are not recalculated. To
   actually recalculate paths, you need a clean PyConfig.
*/
PyStatus
_PyConfig_InitPathConfig(PyConfig *config, int compute_path_config)
{
    PyStatus status = _PyPathConfig_ReadGlobal(config);

    if (_PyStatus_EXCEPTION(status) || !compute_path_config) {
        return status;
    }

    if (!_PyThreadState_UncheckedGet()) {
        return PyStatus_Error("cannot calculate path configuration without GIL");
    }

    PyObject *configDict = _PyConfig_AsDict(config);
    if (!configDict) {
        PyErr_Clear();
        return PyStatus_NoMemory();
    }

    PyObject *dict = PyDict_New();
    if (!dict) {
        PyErr_Clear();
        Py_DECREF(configDict);
        return PyStatus_NoMemory();
    }

    if (PyDict_SetItemString(dict, "config", configDict) < 0) {
        PyErr_Clear();
        Py_DECREF(configDict);
        Py_DECREF(dict);
        return PyStatus_NoMemory();
    }
    /* reference now held by dict */
    Py_DECREF(configDict);

    PyObject *co = _Py_Get_Getpath_CodeObject();
    if (!co || !PyCode_Check(co)) {
        PyErr_Clear();
        Py_XDECREF(co);
        Py_DECREF(dict);
        return PyStatus_Error("error reading frozen getpath.py");
    }

#ifdef MS_WINDOWS
    PyObject *winreg = PyImport_ImportModule("winreg");
    if (!winreg || PyDict_SetItemString(dict, "winreg", winreg) < 0) {
        PyErr_Clear();
        Py_XDECREF(winreg);
        if (PyDict_SetItemString(dict, "winreg", Py_None) < 0) {
            PyErr_Clear();
            Py_DECREF(co);
            Py_DECREF(dict);
            return PyStatus_Error("error importing winreg module");
        }
    } else {
        Py_DECREF(winreg);
    }
#endif

    if (
#ifdef MS_WINDOWS
        !decode_to_dict(dict, "os_name", "nt") ||
#elif defined(__APPLE__)
        !decode_to_dict(dict, "os_name", "darwin") ||
#else
        !decode_to_dict(dict, "os_name", "posix") ||
#endif
#ifdef WITH_NEXT_FRAMEWORK
        !int_to_dict(dict, "WITH_NEXT_FRAMEWORK", 1) ||
#else
        !int_to_dict(dict, "WITH_NEXT_FRAMEWORK", 0) ||
#endif
        !decode_to_dict(dict, "PREFIX", PREFIX) ||
        !decode_to_dict(dict, "EXEC_PREFIX", EXEC_PREFIX) ||
        !decode_to_dict(dict, "PYTHONPATH", PYTHONPATH) ||
        !decode_to_dict(dict, "VPATH", VPATH) ||
        !decode_to_dict(dict, "PLATLIBDIR", PLATLIBDIR) ||
        !decode_to_dict(dict, "PYDEBUGEXT", PYDEBUGEXT) ||
        !int_to_dict(dict, "VERSION_MAJOR", PY_MAJOR_VERSION) ||
        !int_to_dict(dict, "VERSION_MINOR", PY_MINOR_VERSION) ||
        !decode_to_dict(dict, "PYWINVER", PYWINVER) ||
        !wchar_to_dict(dict, "EXE_SUFFIX", EXE_SUFFIX) ||
        !env_to_dict(dict, "ENV_PATH", 0) ||
        !env_to_dict(dict, "ENV_PYTHONHOME", 0) ||
        !env_to_dict(dict, "ENV_PYTHONEXECUTABLE", 0) ||
        !env_to_dict(dict, "ENV___PYVENV_LAUNCHER__", 1) ||
        !progname_to_dict(dict, "real_executable") ||
        !library_to_dict(dict, "library") ||
        !wchar_to_dict(dict, "executable_dir", NULL) ||
        !wchar_to_dict(dict, "py_setpath", _PyPathConfig_GetGlobalModuleSearchPath()) ||
        !funcs_to_dict(dict, config->pathconfig_warnings) ||
#ifndef MS_WINDOWS
        PyDict_SetItemString(dict, "winreg", Py_None) < 0 ||
#endif
        PyDict_SetItemString(dict, "__builtins__", PyEval_GetBuiltins()) < 0
    ) {
        Py_DECREF(co);
        Py_DECREF(dict);
        _PyErr_WriteUnraisableMsg("error evaluating initial values", NULL);
        return PyStatus_Error("error evaluating initial values");
    }

    PyObject *r = PyEval_EvalCode(co, dict, dict);
    Py_DECREF(co);

    if (!r) {
        Py_DECREF(dict);
        _PyErr_WriteUnraisableMsg("error evaluating path", NULL);
        return PyStatus_Error("error evaluating path");
    }
    Py_DECREF(r);

    if (_PyConfig_FromDict(config, configDict) < 0) {
        _PyErr_WriteUnraisableMsg("reading getpath results", NULL);
        Py_DECREF(dict);
        return PyStatus_Error("error getting getpath results");
    }

    Py_DECREF(dict);

    return _PyStatus_OK();
}