summaryrefslogtreecommitdiffstats
path: root/Python/fileutils.c
blob: 27924261f439619a572969ab56efea13bbb75504 (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
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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
#include "Python.h"
#include "pycore_fileutils.h"     // fileutils definitions
#include "pycore_runtime.h"       // _PyRuntime
#include "osdefs.h"               // SEP
#include <locale.h>
#include <stdlib.h>               // mbstowcs()

#ifdef MS_WINDOWS
#  include <malloc.h>
#  include <windows.h>
#  include <pathcch.h>            // PathCchCombineEx
extern int winerror_to_errno(int);
#endif

#ifdef HAVE_LANGINFO_H
#include <langinfo.h>
#endif

#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif

#ifdef HAVE_NON_UNICODE_WCHAR_T_REPRESENTATION
#include <iconv.h>
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */

#ifdef O_CLOEXEC
/* Does open() support the O_CLOEXEC flag? Possible values:

   -1: unknown
    0: open() ignores O_CLOEXEC flag, ex: Linux kernel older than 2.6.23
    1: open() supports O_CLOEXEC flag, close-on-exec is set

   The flag is used by _Py_open(), _Py_open_noraise(), io.FileIO
   and os.open(). */
int _Py_open_cloexec_works = -1;
#endif

// The value must be the same in unicodeobject.c.
#define MAX_UNICODE 0x10ffff

// mbstowcs() and mbrtowc() errors
static const size_t DECODE_ERROR = ((size_t)-1);
static const size_t INCOMPLETE_CHARACTER = (size_t)-2;


static int
get_surrogateescape(_Py_error_handler errors, int *surrogateescape)
{
    switch (errors)
    {
    case _Py_ERROR_STRICT:
        *surrogateescape = 0;
        return 0;
    case _Py_ERROR_SURROGATEESCAPE:
        *surrogateescape = 1;
        return 0;
    default:
        return -1;
    }
}


PyObject *
_Py_device_encoding(int fd)
{
    int valid;
    Py_BEGIN_ALLOW_THREADS
    _Py_BEGIN_SUPPRESS_IPH
    valid = isatty(fd);
    _Py_END_SUPPRESS_IPH
    Py_END_ALLOW_THREADS
    if (!valid)
        Py_RETURN_NONE;

#if defined(MS_WINDOWS)
    UINT cp;
    if (fd == 0)
        cp = GetConsoleCP();
    else if (fd == 1 || fd == 2)
        cp = GetConsoleOutputCP();
    else
        cp = 0;
    /* GetConsoleCP() and GetConsoleOutputCP() return 0 if the application
       has no console */
    if (cp == 0) {
        Py_RETURN_NONE;
    }

    return PyUnicode_FromFormat("cp%u", (unsigned int)cp);
#else
    if (_PyRuntime.preconfig.utf8_mode) {
        _Py_DECLARE_STR(utf_8, "utf-8");
        return Py_NewRef(&_Py_STR(utf_8));
    }
    return _Py_GetLocaleEncodingObject();
#endif
}


static size_t
is_valid_wide_char(wchar_t ch)
{
#ifdef HAVE_NON_UNICODE_WCHAR_T_REPRESENTATION
    /* Oracle Solaris doesn't use Unicode code points as wchar_t encoding
       for non-Unicode locales, which makes values higher than MAX_UNICODE
       possibly valid. */
    return 1;
#endif
    if (Py_UNICODE_IS_SURROGATE(ch)) {
        // Reject lone surrogate characters
        return 0;
    }
    if (ch > MAX_UNICODE) {
        // bpo-35883: Reject characters outside [U+0000; U+10ffff] range.
        // The glibc mbstowcs() UTF-8 decoder does not respect the RFC 3629,
        // it creates characters outside the [U+0000; U+10ffff] range:
        // https://sourceware.org/bugzilla/show_bug.cgi?id=2373
        return 0;
    }
    return 1;
}


static size_t
_Py_mbstowcs(wchar_t *dest, const char *src, size_t n)
{
    size_t count = mbstowcs(dest, src, n);
    if (dest != NULL && count != DECODE_ERROR) {
        for (size_t i=0; i < count; i++) {
            wchar_t ch = dest[i];
            if (!is_valid_wide_char(ch)) {
                return DECODE_ERROR;
            }
        }
    }
    return count;
}


#ifdef HAVE_MBRTOWC
static size_t
_Py_mbrtowc(wchar_t *pwc, const char *str, size_t len, mbstate_t *pmbs)
{
    assert(pwc != NULL);
    size_t count = mbrtowc(pwc, str, len, pmbs);
    if (count != 0 && count != DECODE_ERROR && count != INCOMPLETE_CHARACTER) {
        if (!is_valid_wide_char(*pwc)) {
            return DECODE_ERROR;
        }
    }
    return count;
}
#endif


#if !defined(_Py_FORCE_UTF8_FS_ENCODING) && !defined(MS_WINDOWS)

#define USE_FORCE_ASCII

extern int _Py_normalize_encoding(const char *, char *, size_t);

/* Workaround FreeBSD and OpenIndiana locale encoding issue with the C locale
   and POSIX locale. nl_langinfo(CODESET) announces an alias of the
   ASCII encoding, whereas mbstowcs() and wcstombs() functions use the
   ISO-8859-1 encoding. The problem is that os.fsencode() and os.fsdecode() use
   locale.getpreferredencoding() codec. For example, if command line arguments
   are decoded by mbstowcs() and encoded back by os.fsencode(), we get a
   UnicodeEncodeError instead of retrieving the original byte string.

   The workaround is enabled if setlocale(LC_CTYPE, NULL) returns "C",
   nl_langinfo(CODESET) announces "ascii" (or an alias to ASCII), and at least
   one byte in range 0x80-0xff can be decoded from the locale encoding. The
   workaround is also enabled on error, for example if getting the locale
   failed.

   On HP-UX with the C locale or the POSIX locale, nl_langinfo(CODESET)
   announces "roman8" but mbstowcs() uses Latin1 in practice. Force also the
   ASCII encoding in this case.

   Values of force_ascii:

       1: the workaround is used: Py_EncodeLocale() uses
          encode_ascii_surrogateescape() and Py_DecodeLocale() uses
          decode_ascii()
       0: the workaround is not used: Py_EncodeLocale() uses wcstombs() and
          Py_DecodeLocale() uses mbstowcs()
      -1: unknown, need to call check_force_ascii() to get the value
*/
static int force_ascii = -1;

static int
check_force_ascii(void)
{
    char *loc = setlocale(LC_CTYPE, NULL);
    if (loc == NULL) {
        goto error;
    }
    if (strcmp(loc, "C") != 0 && strcmp(loc, "POSIX") != 0) {
        /* the LC_CTYPE locale is different than C and POSIX */
        return 0;
    }

#if defined(HAVE_LANGINFO_H) && defined(CODESET)
    const char *codeset = nl_langinfo(CODESET);
    if (!codeset || codeset[0] == '\0') {
        /* CODESET is not set or empty */
        goto error;
    }

    char encoding[20];   /* longest name: "iso_646.irv_1991\0" */
    if (!_Py_normalize_encoding(codeset, encoding, sizeof(encoding))) {
        goto error;
    }

#ifdef __hpux
    if (strcmp(encoding, "roman8") == 0) {
        unsigned char ch;
        wchar_t wch;
        size_t res;

        ch = (unsigned char)0xA7;
        res = _Py_mbstowcs(&wch, (char*)&ch, 1);
        if (res != DECODE_ERROR && wch == L'\xA7') {
            /* On HP-UX with C locale or the POSIX locale,
               nl_langinfo(CODESET) announces "roman8", whereas mbstowcs() uses
               Latin1 encoding in practice. Force ASCII in this case.

               Roman8 decodes 0xA7 to U+00CF. Latin1 decodes 0xA7 to U+00A7. */
            return 1;
        }
    }
#else
    const char* ascii_aliases[] = {
        "ascii",
        /* Aliases from Lib/encodings/aliases.py */
        "646",
        "ansi_x3.4_1968",
        "ansi_x3.4_1986",
        "ansi_x3_4_1968",
        "cp367",
        "csascii",
        "ibm367",
        "iso646_us",
        "iso_646.irv_1991",
        "iso_ir_6",
        "us",
        "us_ascii",
        NULL
    };

    int is_ascii = 0;
    for (const char **alias=ascii_aliases; *alias != NULL; alias++) {
        if (strcmp(encoding, *alias) == 0) {
            is_ascii = 1;
            break;
        }
    }
    if (!is_ascii) {
        /* nl_langinfo(CODESET) is not "ascii" or an alias of ASCII */
        return 0;
    }

    for (unsigned int i=0x80; i<=0xff; i++) {
        char ch[1];
        wchar_t wch[1];
        size_t res;

        unsigned uch = (unsigned char)i;
        ch[0] = (char)uch;
        res = _Py_mbstowcs(wch, ch, 1);
        if (res != DECODE_ERROR) {
            /* decoding a non-ASCII character from the locale encoding succeed:
               the locale encoding is not ASCII, force ASCII */
            return 1;
        }
    }
    /* None of the bytes in the range 0x80-0xff can be decoded from the locale
       encoding: the locale encoding is really ASCII */
#endif   /* !defined(__hpux) */
    return 0;
#else
    /* nl_langinfo(CODESET) is not available: always force ASCII */
    return 1;
#endif   /* defined(HAVE_LANGINFO_H) && defined(CODESET) */

error:
    /* if an error occurred, force the ASCII encoding */
    return 1;
}


int
_Py_GetForceASCII(void)
{
    if (force_ascii == -1) {
        force_ascii = check_force_ascii();
    }
    return force_ascii;
}


void
_Py_ResetForceASCII(void)
{
    force_ascii = -1;
}


static int
encode_ascii(const wchar_t *text, char **str,
             size_t *error_pos, const char **reason,
             int raw_malloc, _Py_error_handler errors)
{
    char *result = NULL, *out;
    size_t len, i;
    wchar_t ch;

    int surrogateescape;
    if (get_surrogateescape(errors, &surrogateescape) < 0) {
        return -3;
    }

    len = wcslen(text);

    /* +1 for NULL byte */
    if (raw_malloc) {
        result = PyMem_RawMalloc(len + 1);
    }
    else {
        result = PyMem_Malloc(len + 1);
    }
    if (result == NULL) {
        return -1;
    }

    out = result;
    for (i=0; i<len; i++) {
        ch = text[i];

        if (ch <= 0x7f) {
            /* ASCII character */
            *out++ = (char)ch;
        }
        else if (surrogateescape && 0xdc80 <= ch && ch <= 0xdcff) {
            /* UTF-8b surrogate */
            *out++ = (char)(ch - 0xdc00);
        }
        else {
            if (raw_malloc) {
                PyMem_RawFree(result);
            }
            else {
                PyMem_Free(result);
            }
            if (error_pos != NULL) {
                *error_pos = i;
            }
            if (reason) {
                *reason = "encoding error";
            }
            return -2;
        }
    }
    *out = '\0';
    *str = result;
    return 0;
}
#else
int
_Py_GetForceASCII(void)
{
    return 0;
}

void
_Py_ResetForceASCII(void)
{
    /* nothing to do */
}
#endif   /* !defined(_Py_FORCE_UTF8_FS_ENCODING) && !defined(MS_WINDOWS) */


#if !defined(HAVE_MBRTOWC) || defined(USE_FORCE_ASCII)
static int
decode_ascii(const char *arg, wchar_t **wstr, size_t *wlen,
             const char **reason, _Py_error_handler errors)
{
    wchar_t *res;
    unsigned char *in;
    wchar_t *out;
    size_t argsize = strlen(arg) + 1;

    int surrogateescape;
    if (get_surrogateescape(errors, &surrogateescape) < 0) {
        return -3;
    }

    if (argsize > PY_SSIZE_T_MAX / sizeof(wchar_t)) {
        return -1;
    }
    res = PyMem_RawMalloc(argsize * sizeof(wchar_t));
    if (!res) {
        return -1;
    }

    out = res;
    for (in = (unsigned char*)arg; *in; in++) {
        unsigned char ch = *in;
        if (ch < 128) {
            *out++ = ch;
        }
        else {
            if (!surrogateescape) {
                PyMem_RawFree(res);
                if (wlen) {
                    *wlen = in - (unsigned char*)arg;
                }
                if (reason) {
                    *reason = "decoding error";
                }
                return -2;
            }
            *out++ = 0xdc00 + ch;
        }
    }
    *out = 0;

    if (wlen != NULL) {
        *wlen = out - res;
    }
    *wstr = res;
    return 0;
}
#endif   /* !HAVE_MBRTOWC */

static int
decode_current_locale(const char* arg, wchar_t **wstr, size_t *wlen,
                      const char **reason, _Py_error_handler errors)
{
    wchar_t *res;
    size_t argsize;
    size_t count;
#ifdef HAVE_MBRTOWC
    unsigned char *in;
    wchar_t *out;
    mbstate_t mbs;
#endif

    int surrogateescape;
    if (get_surrogateescape(errors, &surrogateescape) < 0) {
        return -3;
    }

#ifdef HAVE_BROKEN_MBSTOWCS
    /* Some platforms have a broken implementation of
     * mbstowcs which does not count the characters that
     * would result from conversion.  Use an upper bound.
     */
    argsize = strlen(arg);
#else
    argsize = _Py_mbstowcs(NULL, arg, 0);
#endif
    if (argsize != DECODE_ERROR) {
        if (argsize > PY_SSIZE_T_MAX / sizeof(wchar_t) - 1) {
            return -1;
        }
        res = (wchar_t *)PyMem_RawMalloc((argsize + 1) * sizeof(wchar_t));
        if (!res) {
            return -1;
        }

        count = _Py_mbstowcs(res, arg, argsize + 1);
        if (count != DECODE_ERROR) {
            *wstr = res;
            if (wlen != NULL) {
                *wlen = count;
            }
            return 0;
        }
        PyMem_RawFree(res);
    }

    /* Conversion failed. Fall back to escaping with surrogateescape. */
#ifdef HAVE_MBRTOWC
    /* Try conversion with mbrtwoc (C99), and escape non-decodable bytes. */

    /* Overallocate; as multi-byte characters are in the argument, the
       actual output could use less memory. */
    argsize = strlen(arg) + 1;
    if (argsize > PY_SSIZE_T_MAX / sizeof(wchar_t)) {
        return -1;
    }
    res = (wchar_t*)PyMem_RawMalloc(argsize * sizeof(wchar_t));
    if (!res) {
        return -1;
    }

    in = (unsigned char*)arg;
    out = res;
    memset(&mbs, 0, sizeof mbs);
    while (argsize) {
        size_t converted = _Py_mbrtowc(out, (char*)in, argsize, &mbs);
        if (converted == 0) {
            /* Reached end of string; null char stored. */
            break;
        }

        if (converted == INCOMPLETE_CHARACTER) {
            /* Incomplete character. This should never happen,
               since we provide everything that we have -
               unless there is a bug in the C library, or I
               misunderstood how mbrtowc works. */
            goto decode_error;
        }

        if (converted == DECODE_ERROR) {
            if (!surrogateescape) {
                goto decode_error;
            }

            /* Decoding error. Escape as UTF-8b, and start over in the initial
               shift state. */
            *out++ = 0xdc00 + *in++;
            argsize--;
            memset(&mbs, 0, sizeof mbs);
            continue;
        }

        // _Py_mbrtowc() reject lone surrogate characters
        assert(!Py_UNICODE_IS_SURROGATE(*out));

        /* successfully converted some bytes */
        in += converted;
        argsize -= converted;
        out++;
    }
    if (wlen != NULL) {
        *wlen = out - res;
    }
    *wstr = res;
    return 0;

decode_error:
    PyMem_RawFree(res);
    if (wlen) {
        *wlen = in - (unsigned char*)arg;
    }
    if (reason) {
        *reason = "decoding error";
    }
    return -2;
#else   /* HAVE_MBRTOWC */
    /* Cannot use C locale for escaping; manually escape as if charset
       is ASCII (i.e. escape all bytes > 128. This will still roundtrip
       correctly in the locale's charset, which must be an ASCII superset. */
    return decode_ascii(arg, wstr, wlen, reason, errors);
#endif   /* HAVE_MBRTOWC */
}


/* Decode a byte string from the locale encoding.

   Use the strict error handler if 'surrogateescape' is zero.  Use the
   surrogateescape error handler if 'surrogateescape' is non-zero: undecodable
   bytes are decoded as characters in range U+DC80..U+DCFF. If a byte sequence
   can be decoded as a surrogate character, escape the bytes using the
   surrogateescape error handler instead of decoding them.

   On success, return 0 and write the newly allocated wide character string into
   *wstr (use PyMem_RawFree() to free the memory). If wlen is not NULL, write
   the number of wide characters excluding the null character into *wlen.

   On memory allocation failure, return -1.

   On decoding error, return -2. If wlen is not NULL, write the start of
   invalid byte sequence in the input string into *wlen. If reason is not NULL,
   write the decoding error message into *reason.

   Return -3 if the error handler 'errors' is not supported.

   Use the Py_EncodeLocaleEx() function to encode the character string back to
   a byte string. */
int
_Py_DecodeLocaleEx(const char* arg, wchar_t **wstr, size_t *wlen,
                   const char **reason,
                   int current_locale, _Py_error_handler errors)
{
    if (current_locale) {
#ifdef _Py_FORCE_UTF8_LOCALE
        return _Py_DecodeUTF8Ex(arg, strlen(arg), wstr, wlen, reason,
                                errors);
#else
        return decode_current_locale(arg, wstr, wlen, reason, errors);
#endif
    }

#ifdef _Py_FORCE_UTF8_FS_ENCODING
    return _Py_DecodeUTF8Ex(arg, strlen(arg), wstr, wlen, reason,
                            errors);
#else
    int use_utf8 = (Py_UTF8Mode == 1);
#ifdef MS_WINDOWS
    use_utf8 |= !Py_LegacyWindowsFSEncodingFlag;
#endif
    if (use_utf8) {
        return _Py_DecodeUTF8Ex(arg, strlen(arg), wstr, wlen, reason,
                                errors);
    }

#ifdef USE_FORCE_ASCII
    if (force_ascii == -1) {
        force_ascii = check_force_ascii();
    }

    if (force_ascii) {
        /* force ASCII encoding to workaround mbstowcs() issue */
        return decode_ascii(arg, wstr, wlen, reason, errors);
    }
#endif

    return decode_current_locale(arg, wstr, wlen, reason, errors);
#endif   /* !_Py_FORCE_UTF8_FS_ENCODING */
}


/* Decode a byte string from the locale encoding with the
   surrogateescape error handler: undecodable bytes are decoded as characters
   in range U+DC80..U+DCFF. If a byte sequence can be decoded as a surrogate
   character, escape the bytes using the surrogateescape error handler instead
   of decoding them.

   Return a pointer to a newly allocated wide character string, use
   PyMem_RawFree() to free the memory. If size is not NULL, write the number of
   wide characters excluding the null character into *size

   Return NULL on decoding error or memory allocation error. If *size* is not
   NULL, *size is set to (size_t)-1 on memory error or set to (size_t)-2 on
   decoding error.

   Decoding errors should never happen, unless there is a bug in the C
   library.

   Use the Py_EncodeLocale() function to encode the character string back to a
   byte string. */
wchar_t*
Py_DecodeLocale(const char* arg, size_t *wlen)
{
    wchar_t *wstr;
    int res = _Py_DecodeLocaleEx(arg, &wstr, wlen,
                                 NULL, 0,
                                 _Py_ERROR_SURROGATEESCAPE);
    if (res != 0) {
        assert(res != -3);
        if (wlen != NULL) {
            *wlen = (size_t)res;
        }
        return NULL;
    }
    return wstr;
}


static int
encode_current_locale(const wchar_t *text, char **str,
                      size_t *error_pos, const char **reason,
                      int raw_malloc, _Py_error_handler errors)
{
    const size_t len = wcslen(text);
    char *result = NULL, *bytes = NULL;
    size_t i, size, converted;
    wchar_t c, buf[2];

    int surrogateescape;
    if (get_surrogateescape(errors, &surrogateescape) < 0) {
        return -3;
    }

    /* The function works in two steps:
       1. compute the length of the output buffer in bytes (size)
       2. outputs the bytes */
    size = 0;
    buf[1] = 0;
    while (1) {
        for (i=0; i < len; i++) {
            c = text[i];
            if (c >= 0xdc80 && c <= 0xdcff) {
                if (!surrogateescape) {
                    goto encode_error;
                }
                /* UTF-8b surrogate */
                if (bytes != NULL) {
                    *bytes++ = c - 0xdc00;
                    size--;
                }
                else {
                    size++;
                }
                continue;
            }
            else {
                buf[0] = c;
                if (bytes != NULL) {
                    converted = wcstombs(bytes, buf, size);
                }
                else {
                    converted = wcstombs(NULL, buf, 0);
                }
                if (converted == DECODE_ERROR) {
                    goto encode_error;
                }
                if (bytes != NULL) {
                    bytes += converted;
                    size -= converted;
                }
                else {
                    size += converted;
                }
            }
        }
        if (result != NULL) {
            *bytes = '\0';
            break;
        }

        size += 1; /* nul byte at the end */
        if (raw_malloc) {
            result = PyMem_RawMalloc(size);
        }
        else {
            result = PyMem_Malloc(size);
        }
        if (result == NULL) {
            return -1;
        }
        bytes = result;
    }
    *str = result;
    return 0;

encode_error:
    if (raw_malloc) {
        PyMem_RawFree(result);
    }
    else {
        PyMem_Free(result);
    }
    if (error_pos != NULL) {
        *error_pos = i;
    }
    if (reason) {
        *reason = "encoding error";
    }
    return -2;
}


/* Encode a string to the locale encoding.

   Parameters:

   * raw_malloc: if non-zero, allocate memory using PyMem_RawMalloc() instead
     of PyMem_Malloc().
   * current_locale: if non-zero, use the current LC_CTYPE, otherwise use
     Python filesystem encoding.
   * errors: error handler like "strict" or "surrogateescape".

   Return value:

    0: success, *str is set to a newly allocated decoded string.
   -1: memory allocation failure
   -2: encoding error, set *error_pos and *reason (if set).
   -3: the error handler 'errors' is not supported.
 */
static int
encode_locale_ex(const wchar_t *text, char **str, size_t *error_pos,
                 const char **reason,
                 int raw_malloc, int current_locale, _Py_error_handler errors)
{
    if (current_locale) {
#ifdef _Py_FORCE_UTF8_LOCALE
        return _Py_EncodeUTF8Ex(text, str, error_pos, reason,
                                raw_malloc, errors);
#else
        return encode_current_locale(text, str, error_pos, reason,
                                     raw_malloc, errors);
#endif
    }

#ifdef _Py_FORCE_UTF8_FS_ENCODING
    return _Py_EncodeUTF8Ex(text, str, error_pos, reason,
                            raw_malloc, errors);
#else
    int use_utf8 = (Py_UTF8Mode == 1);
#ifdef MS_WINDOWS
    use_utf8 |= !Py_LegacyWindowsFSEncodingFlag;
#endif
    if (use_utf8) {
        return _Py_EncodeUTF8Ex(text, str, error_pos, reason,
                                raw_malloc, errors);
    }

#ifdef USE_FORCE_ASCII
    if (force_ascii == -1) {
        force_ascii = check_force_ascii();
    }

    if (force_ascii) {
        return encode_ascii(text, str, error_pos, reason,
                            raw_malloc, errors);
    }
#endif

    return encode_current_locale(text, str, error_pos, reason,
                                 raw_malloc, errors);
#endif   /* _Py_FORCE_UTF8_FS_ENCODING */
}

static char*
encode_locale(const wchar_t *text, size_t *error_pos,
              int raw_malloc, int current_locale)
{
    char *str;
    int res = encode_locale_ex(text, &str, error_pos, NULL,
                               raw_malloc, current_locale,
                               _Py_ERROR_SURROGATEESCAPE);
    if (res != -2 && error_pos) {
        *error_pos = (size_t)-1;
    }
    if (res != 0) {
        return NULL;
    }
    return str;
}

/* Encode a wide character string to the locale encoding with the
   surrogateescape error handler: surrogate characters in the range
   U+DC80..U+DCFF are converted to bytes 0x80..0xFF.

   Return a pointer to a newly allocated byte string, use PyMem_Free() to free
   the memory. Return NULL on encoding or memory allocation error.

   If error_pos is not NULL, *error_pos is set to (size_t)-1 on success, or set
   to the index of the invalid character on encoding error.

   Use the Py_DecodeLocale() function to decode the bytes string back to a wide
   character string. */
char*
Py_EncodeLocale(const wchar_t *text, size_t *error_pos)
{
    return encode_locale(text, error_pos, 0, 0);
}


/* Similar to Py_EncodeLocale(), but result must be freed by PyMem_RawFree()
   instead of PyMem_Free(). */
char*
_Py_EncodeLocaleRaw(const wchar_t *text, size_t *error_pos)
{
    return encode_locale(text, error_pos, 1, 0);
}


int
_Py_EncodeLocaleEx(const wchar_t *text, char **str,
                   size_t *error_pos, const char **reason,
                   int current_locale, _Py_error_handler errors)
{
    return encode_locale_ex(text, str, error_pos, reason, 1,
                            current_locale, errors);
}


// Get the current locale encoding name:
//
// - Return "utf-8" if _Py_FORCE_UTF8_LOCALE macro is defined (ex: on Android)
// - Return "utf-8" if the UTF-8 Mode is enabled
// - On Windows, return the ANSI code page (ex: "cp1250")
// - Return "utf-8" if nl_langinfo(CODESET) returns an empty string.
// - Otherwise, return nl_langinfo(CODESET).
//
// Return NULL on memory allocation failure.
//
// See also config_get_locale_encoding()
wchar_t*
_Py_GetLocaleEncoding(void)
{
#ifdef _Py_FORCE_UTF8_LOCALE
    // On Android langinfo.h and CODESET are missing,
    // and UTF-8 is always used in mbstowcs() and wcstombs().
    return _PyMem_RawWcsdup(L"utf-8");
#else

#ifdef MS_WINDOWS
    wchar_t encoding[23];
    unsigned int ansi_codepage = GetACP();
    swprintf(encoding, Py_ARRAY_LENGTH(encoding), L"cp%u", ansi_codepage);
    encoding[Py_ARRAY_LENGTH(encoding) - 1] = 0;
    return _PyMem_RawWcsdup(encoding);
#else
    const char *encoding = nl_langinfo(CODESET);
    if (!encoding || encoding[0] == '\0') {
        // Use UTF-8 if nl_langinfo() returns an empty string. It can happen on
        // macOS if the LC_CTYPE locale is not supported.
        return _PyMem_RawWcsdup(L"utf-8");
    }

    wchar_t *wstr;
    int res = decode_current_locale(encoding, &wstr, NULL,
                                    NULL, _Py_ERROR_SURROGATEESCAPE);
    if (res < 0) {
        return NULL;
    }
    return wstr;
#endif  // !MS_WINDOWS

#endif  // !_Py_FORCE_UTF8_LOCALE
}


PyObject *
_Py_GetLocaleEncodingObject(void)
{
    wchar_t *encoding = _Py_GetLocaleEncoding();
    if (encoding == NULL) {
        PyErr_NoMemory();
        return NULL;
    }

    PyObject *str = PyUnicode_FromWideChar(encoding, -1);
    PyMem_RawFree(encoding);
    return str;
}

#ifdef HAVE_NON_UNICODE_WCHAR_T_REPRESENTATION

/* Check whether current locale uses Unicode as internal wchar_t form. */
int
_Py_LocaleUsesNonUnicodeWchar(void)
{
    /* Oracle Solaris uses non-Unicode internal wchar_t form for
       non-Unicode locales and hence needs conversion to UTF first. */
    char* codeset = nl_langinfo(CODESET);
    if (!codeset) {
        return 0;
    }
    /* 646 refers to ISO/IEC 646 standard that corresponds to ASCII encoding */
    return (strcmp(codeset, "UTF-8") != 0 && strcmp(codeset, "646") != 0);
}

static wchar_t *
_Py_ConvertWCharForm(const wchar_t *source, Py_ssize_t size,
                     const char *tocode, const char *fromcode)
{
    static_assert(sizeof(wchar_t) == 4, "wchar_t must be 32-bit");

    /* Ensure we won't overflow the size. */
    if (size > (PY_SSIZE_T_MAX / (Py_ssize_t)sizeof(wchar_t))) {
        PyErr_NoMemory();
        return NULL;
    }

    /* the string doesn't have to be NULL terminated */
    wchar_t* target = PyMem_Malloc(size * sizeof(wchar_t));
    if (target == NULL) {
        PyErr_NoMemory();
        return NULL;
    }

    iconv_t cd = iconv_open(tocode, fromcode);
    if (cd == (iconv_t)-1) {
        PyErr_Format(PyExc_ValueError, "iconv_open() failed");
        PyMem_Free(target);
        return NULL;
    }

    char *inbuf = (char *) source;
    char *outbuf = (char *) target;
    size_t inbytesleft = sizeof(wchar_t) * size;
    size_t outbytesleft = inbytesleft;

    size_t ret = iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
    if (ret == DECODE_ERROR) {
        PyErr_Format(PyExc_ValueError, "iconv() failed");
        PyMem_Free(target);
        iconv_close(cd);
        return NULL;
    }

    iconv_close(cd);
    return target;
}

/* Convert a wide character string to the UCS-4 encoded string. This
   is necessary on systems where internal form of wchar_t are not Unicode
   code points (e.g. Oracle Solaris).

   Return a pointer to a newly allocated string, use PyMem_Free() to free
   the memory. Return NULL and raise exception on conversion or memory
   allocation error. */
wchar_t *
_Py_DecodeNonUnicodeWchar(const wchar_t *native, Py_ssize_t size)
{
    return _Py_ConvertWCharForm(native, size, "UCS-4-INTERNAL", "wchar_t");
}

/* Convert a UCS-4 encoded string to native wide character string. This
   is necessary on systems where internal form of wchar_t are not Unicode
   code points (e.g. Oracle Solaris).

   The conversion is done in place. This can be done because both wchar_t
   and UCS-4 use 4-byte encoding, and one wchar_t symbol always correspond
   to a single UCS-4 symbol and vice versa. (This is true for Oracle Solaris,
   which is currently the only system using these functions; it doesn't have
   to be for other systems).

   Return 0 on success. Return -1 and raise exception on conversion
   or memory allocation error. */
int
_Py_EncodeNonUnicodeWchar_InPlace(wchar_t *unicode, Py_ssize_t size)
{
    wchar_t* result = _Py_ConvertWCharForm(unicode, size, "wchar_t", "UCS-4-INTERNAL");
    if (!result) {
        return -1;
    }
    memcpy(unicode, result, size * sizeof(wchar_t));
    PyMem_Free(result);
    return 0;
}
#endif /* HAVE_NON_UNICODE_WCHAR_T_REPRESENTATION */

#ifdef MS_WINDOWS
static __int64 secs_between_epochs = 11644473600; /* Seconds between 1.1.1601 and 1.1.1970 */

static void
FILE_TIME_to_time_t_nsec(FILETIME *in_ptr, time_t *time_out, int* nsec_out)
{
    /* XXX endianness. Shouldn't matter, as all Windows implementations are little-endian */
    /* Cannot simply cast and dereference in_ptr,
       since it might not be aligned properly */
    __int64 in;
    memcpy(&in, in_ptr, sizeof(in));
    *nsec_out = (int)(in % 10000000) * 100; /* FILETIME is in units of 100 nsec. */
    *time_out = Py_SAFE_DOWNCAST((in / 10000000) - secs_between_epochs, __int64, time_t);
}

void
_Py_time_t_to_FILE_TIME(time_t time_in, int nsec_in, FILETIME *out_ptr)
{
    /* XXX endianness */
    __int64 out;
    out = time_in + secs_between_epochs;
    out = out * 10000000 + nsec_in / 100;
    memcpy(out_ptr, &out, sizeof(out));
}

/* Below, we *know* that ugo+r is 0444 */
#if _S_IREAD != 0400
#error Unsupported C library
#endif
static int
attributes_to_mode(DWORD attr)
{
    int m = 0;
    if (attr & FILE_ATTRIBUTE_DIRECTORY)
        m |= _S_IFDIR | 0111; /* IFEXEC for user,group,other */
    else
        m |= _S_IFREG;
    if (attr & FILE_ATTRIBUTE_READONLY)
        m |= 0444;
    else
        m |= 0666;
    return m;
}

void
_Py_attribute_data_to_stat(BY_HANDLE_FILE_INFORMATION *info, ULONG reparse_tag,
                           struct _Py_stat_struct *result)
{
    memset(result, 0, sizeof(*result));
    result->st_mode = attributes_to_mode(info->dwFileAttributes);
    result->st_size = (((__int64)info->nFileSizeHigh)<<32) + info->nFileSizeLow;
    result->st_dev = info->dwVolumeSerialNumber;
    result->st_rdev = result->st_dev;
    FILE_TIME_to_time_t_nsec(&info->ftCreationTime, &result->st_ctime, &result->st_ctime_nsec);
    FILE_TIME_to_time_t_nsec(&info->ftLastWriteTime, &result->st_mtime, &result->st_mtime_nsec);
    FILE_TIME_to_time_t_nsec(&info->ftLastAccessTime, &result->st_atime, &result->st_atime_nsec);
    result->st_nlink = info->nNumberOfLinks;
    result->st_ino = (((uint64_t)info->nFileIndexHigh) << 32) + info->nFileIndexLow;
    /* bpo-37834: Only actual symlinks set the S_IFLNK flag. But lstat() will
       open other name surrogate reparse points without traversing them. To
       detect/handle these, check st_file_attributes and st_reparse_tag. */
    result->st_reparse_tag = reparse_tag;
    if (info->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
        reparse_tag == IO_REPARSE_TAG_SYMLINK) {
        /* first clear the S_IFMT bits */
        result->st_mode ^= (result->st_mode & S_IFMT);
        /* now set the bits that make this a symlink */
        result->st_mode |= S_IFLNK;
    }
    result->st_file_attributes = info->dwFileAttributes;
}
#endif

/* Return information about a file.

   On POSIX, use fstat().

   On Windows, use GetFileType() and GetFileInformationByHandle() which support
   files larger than 2 GiB.  fstat() may fail with EOVERFLOW on files larger
   than 2 GiB because the file size type is a signed 32-bit integer: see issue
   #23152.

   On Windows, set the last Windows error and return nonzero on error. On
   POSIX, set errno and return nonzero on error. Fill status and return 0 on
   success. */
int
_Py_fstat_noraise(int fd, struct _Py_stat_struct *status)
{
#ifdef MS_WINDOWS
    BY_HANDLE_FILE_INFORMATION info;
    HANDLE h;
    int type;

    h = _Py_get_osfhandle_noraise(fd);

    if (h == INVALID_HANDLE_VALUE) {
        /* errno is already set by _get_osfhandle, but we also set
           the Win32 error for callers who expect that */
        SetLastError(ERROR_INVALID_HANDLE);
        return -1;
    }
    memset(status, 0, sizeof(*status));

    type = GetFileType(h);
    if (type == FILE_TYPE_UNKNOWN) {
        DWORD error = GetLastError();
        if (error != 0) {
            errno = winerror_to_errno(error);
            return -1;
        }
        /* else: valid but unknown file */
    }

    if (type != FILE_TYPE_DISK) {
        if (type == FILE_TYPE_CHAR)
            status->st_mode = _S_IFCHR;
        else if (type == FILE_TYPE_PIPE)
            status->st_mode = _S_IFIFO;
        return 0;
    }

    if (!GetFileInformationByHandle(h, &info)) {
        /* The Win32 error is already set, but we also set errno for
           callers who expect it */
        errno = winerror_to_errno(GetLastError());
        return -1;
    }

    _Py_attribute_data_to_stat(&info, 0, status);
    /* specific to fstat() */
    status->st_ino = (((uint64_t)info.nFileIndexHigh) << 32) + info.nFileIndexLow;
    return 0;
#else
    return fstat(fd, status);
#endif
}

/* Return information about a file.

   On POSIX, use fstat().

   On Windows, use GetFileType() and GetFileInformationByHandle() which support
   files larger than 2 GiB.  fstat() may fail with EOVERFLOW on files larger
   than 2 GiB because the file size type is a signed 32-bit integer: see issue
   #23152.

   Raise an exception and return -1 on error. On Windows, set the last Windows
   error on error. On POSIX, set errno on error. Fill status and return 0 on
   success.

   Release the GIL to call GetFileType() and GetFileInformationByHandle(), or
   to call fstat(). The caller must hold the GIL. */
int
_Py_fstat(int fd, struct _Py_stat_struct *status)
{
    int res;

    assert(PyGILState_Check());

    Py_BEGIN_ALLOW_THREADS
    res = _Py_fstat_noraise(fd, status);
    Py_END_ALLOW_THREADS

    if (res != 0) {
#ifdef MS_WINDOWS
        PyErr_SetFromWindowsErr(0);
#else
        PyErr_SetFromErrno(PyExc_OSError);
#endif
        return -1;
    }
    return 0;
}

/* Like _Py_stat() but with a raw filename. */
int
_Py_wstat(const wchar_t* path, struct stat *buf)
{
    int err;
#ifdef MS_WINDOWS
    struct _stat wstatbuf;
    err = _wstat(path, &wstatbuf);
    if (!err) {
        buf->st_mode = wstatbuf.st_mode;
    }
#else
    char *fname;
    fname = _Py_EncodeLocaleRaw(path, NULL);
    if (fname == NULL) {
        errno = EINVAL;
        return -1;
    }
    err = stat(fname, buf);
    PyMem_RawFree(fname);
#endif
    return err;
}


/* Call _wstat() on Windows, or encode the path to the filesystem encoding and
   call stat() otherwise. Only fill st_mode attribute on Windows.

   Return 0 on success, -1 on _wstat() / stat() error, -2 if an exception was
   raised. */

int
_Py_stat(PyObject *path, struct stat *statbuf)
{
#ifdef MS_WINDOWS
    int err;

#if USE_UNICODE_WCHAR_CACHE
    const wchar_t *wpath = _PyUnicode_AsUnicode(path);
#else /* USE_UNICODE_WCHAR_CACHE */
    wchar_t *wpath = PyUnicode_AsWideCharString(path, NULL);
#endif /* USE_UNICODE_WCHAR_CACHE */
    if (wpath == NULL)
        return -2;

    err = _Py_wstat(wpath, statbuf);
#if !USE_UNICODE_WCHAR_CACHE
    PyMem_Free(wpath);
#endif /* USE_UNICODE_WCHAR_CACHE */
    return err;
#else
    int ret;
    PyObject *bytes;
    char *cpath;

    bytes = PyUnicode_EncodeFSDefault(path);
    if (bytes == NULL)
        return -2;

    /* check for embedded null bytes */
    if (PyBytes_AsStringAndSize(bytes, &cpath, NULL) == -1) {
        Py_DECREF(bytes);
        return -2;
    }

    ret = stat(cpath, statbuf);
    Py_DECREF(bytes);
    return ret;
#endif
}


/* This function MUST be kept async-signal-safe on POSIX when raise=0. */
static int
get_inheritable(int fd, int raise)
{
#ifdef MS_WINDOWS
    HANDLE handle;
    DWORD flags;

    handle = _Py_get_osfhandle_noraise(fd);
    if (handle == INVALID_HANDLE_VALUE) {
        if (raise)
            PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    if (!GetHandleInformation(handle, &flags)) {
        if (raise)
            PyErr_SetFromWindowsErr(0);
        return -1;
    }

    return (flags & HANDLE_FLAG_INHERIT);
#else
    int flags;

    flags = fcntl(fd, F_GETFD, 0);
    if (flags == -1) {
        if (raise)
            PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }
    return !(flags & FD_CLOEXEC);
#endif
}

/* Get the inheritable flag of the specified file descriptor.
   Return 1 if the file descriptor can be inherited, 0 if it cannot,
   raise an exception and return -1 on error. */
int
_Py_get_inheritable(int fd)
{
    return get_inheritable(fd, 1);
}


/* This function MUST be kept async-signal-safe on POSIX when raise=0. */
static int
set_inheritable(int fd, int inheritable, int raise, int *atomic_flag_works)
{
#ifdef MS_WINDOWS
    HANDLE handle;
    DWORD flags;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
    static int ioctl_works = -1;
    int request;
    int err;
#endif
    int flags, new_flags;
    int res;
#endif

    /* atomic_flag_works can only be used to make the file descriptor
       non-inheritable */
    assert(!(atomic_flag_works != NULL && inheritable));

    if (atomic_flag_works != NULL && !inheritable) {
        if (*atomic_flag_works == -1) {
            int isInheritable = get_inheritable(fd, raise);
            if (isInheritable == -1)
                return -1;
            *atomic_flag_works = !isInheritable;
        }

        if (*atomic_flag_works)
            return 0;
    }

#ifdef MS_WINDOWS
    handle = _Py_get_osfhandle_noraise(fd);
    if (handle == INVALID_HANDLE_VALUE) {
        if (raise)
            PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    if (inheritable)
        flags = HANDLE_FLAG_INHERIT;
    else
        flags = 0;

    /* This check can be removed once support for Windows 7 ends. */
#define CONSOLE_PSEUDOHANDLE(handle) (((ULONG_PTR)(handle) & 0x3) == 0x3 && \
        GetFileType(handle) == FILE_TYPE_CHAR)

    if (!CONSOLE_PSEUDOHANDLE(handle) &&
        !SetHandleInformation(handle, HANDLE_FLAG_INHERIT, flags)) {
        if (raise)
            PyErr_SetFromWindowsErr(0);
        return -1;
    }
#undef CONSOLE_PSEUDOHANDLE
    return 0;

#else

#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
    if (ioctl_works != 0 && raise != 0) {
        /* fast-path: ioctl() only requires one syscall */
        /* caveat: raise=0 is an indicator that we must be async-signal-safe
         * thus avoid using ioctl() so we skip the fast-path. */
        if (inheritable)
            request = FIONCLEX;
        else
            request = FIOCLEX;
        err = ioctl(fd, request, NULL);
        if (!err) {
            ioctl_works = 1;
            return 0;
        }

#ifdef O_PATH
        if (errno == EBADF) {
            // bpo-44849: On Linux and FreeBSD, ioctl(FIOCLEX) fails with EBADF
            // on O_PATH file descriptors. Fall through to the fcntl()
            // implementation.
        }
        else
#endif
        if (errno != ENOTTY && errno != EACCES) {
            if (raise)
                PyErr_SetFromErrno(PyExc_OSError);
            return -1;
        }
        else {
            /* Issue #22258: Here, ENOTTY means "Inappropriate ioctl for
               device". The ioctl is declared but not supported by the kernel.
               Remember that ioctl() doesn't work. It is the case on
               Illumos-based OS for example.

               Issue #27057: When SELinux policy disallows ioctl it will fail
               with EACCES. While FIOCLEX is safe operation it may be
               unavailable because ioctl was denied altogether.
               This can be the case on Android. */
            ioctl_works = 0;
        }
        /* fallback to fcntl() if ioctl() does not work */
    }
#endif

    /* slow-path: fcntl() requires two syscalls */
    flags = fcntl(fd, F_GETFD);
    if (flags < 0) {
        if (raise)
            PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    if (inheritable) {
        new_flags = flags & ~FD_CLOEXEC;
    }
    else {
        new_flags = flags | FD_CLOEXEC;
    }

    if (new_flags == flags) {
        /* FD_CLOEXEC flag already set/cleared: nothing to do */
        return 0;
    }

    res = fcntl(fd, F_SETFD, new_flags);
    if (res < 0) {
        if (raise)
            PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }
    return 0;
#endif
}

/* Make the file descriptor non-inheritable.
   Return 0 on success, set errno and return -1 on error. */
static int
make_non_inheritable(int fd)
{
    return set_inheritable(fd, 0, 0, NULL);
}

/* Set the inheritable flag of the specified file descriptor.
   On success: return 0, on error: raise an exception and return -1.

   If atomic_flag_works is not NULL:

    * if *atomic_flag_works==-1, check if the inheritable is set on the file
      descriptor: if yes, set *atomic_flag_works to 1, otherwise set to 0 and
      set the inheritable flag
    * if *atomic_flag_works==1: do nothing
    * if *atomic_flag_works==0: set inheritable flag to False

   Set atomic_flag_works to NULL if no atomic flag was used to create the
   file descriptor.

   atomic_flag_works can only be used to make a file descriptor
   non-inheritable: atomic_flag_works must be NULL if inheritable=1. */
int
_Py_set_inheritable(int fd, int inheritable, int *atomic_flag_works)
{
    return set_inheritable(fd, inheritable, 1, atomic_flag_works);
}

/* Same as _Py_set_inheritable() but on error, set errno and
   don't raise an exception.
   This function is async-signal-safe. */
int
_Py_set_inheritable_async_safe(int fd, int inheritable, int *atomic_flag_works)
{
    return set_inheritable(fd, inheritable, 0, atomic_flag_works);
}

static int
_Py_open_impl(const char *pathname, int flags, int gil_held)
{
    int fd;
    int async_err = 0;
#ifndef MS_WINDOWS
    int *atomic_flag_works;
#endif

#ifdef MS_WINDOWS
    flags |= O_NOINHERIT;
#elif defined(O_CLOEXEC)
    atomic_flag_works = &_Py_open_cloexec_works;
    flags |= O_CLOEXEC;
#else
    atomic_flag_works = NULL;
#endif

    if (gil_held) {
        PyObject *pathname_obj = PyUnicode_DecodeFSDefault(pathname);
        if (pathname_obj == NULL) {
            return -1;
        }
        if (PySys_Audit("open", "OOi", pathname_obj, Py_None, flags) < 0) {
            Py_DECREF(pathname_obj);
            return -1;
        }

        do {
            Py_BEGIN_ALLOW_THREADS
            fd = open(pathname, flags);
            Py_END_ALLOW_THREADS
        } while (fd < 0
                 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
        if (async_err) {
            Py_DECREF(pathname_obj);
            return -1;
        }
        if (fd < 0) {
            PyErr_SetFromErrnoWithFilenameObjects(PyExc_OSError, pathname_obj, NULL);
            Py_DECREF(pathname_obj);
            return -1;
        }
        Py_DECREF(pathname_obj);
    }
    else {
        fd = open(pathname, flags);
        if (fd < 0)
            return -1;
    }

#ifndef MS_WINDOWS
    if (set_inheritable(fd, 0, gil_held, atomic_flag_works) < 0) {
        close(fd);
        return -1;
    }
#endif

    return fd;
}

/* Open a file with the specified flags (wrapper to open() function).
   Return a file descriptor on success. Raise an exception and return -1 on
   error.

   The file descriptor is created non-inheritable.

   When interrupted by a signal (open() fails with EINTR), retry the syscall,
   except if the Python signal handler raises an exception.

   Release the GIL to call open(). The caller must hold the GIL. */
int
_Py_open(const char *pathname, int flags)
{
    /* _Py_open() must be called with the GIL held. */
    assert(PyGILState_Check());
    return _Py_open_impl(pathname, flags, 1);
}

/* Open a file with the specified flags (wrapper to open() function).
   Return a file descriptor on success. Set errno and return -1 on error.

   The file descriptor is created non-inheritable.

   If interrupted by a signal, fail with EINTR. */
int
_Py_open_noraise(const char *pathname, int flags)
{
    return _Py_open_impl(pathname, flags, 0);
}

/* Open a file. Use _wfopen() on Windows, encode the path to the locale
   encoding and use fopen() otherwise.

   The file descriptor is created non-inheritable.

   If interrupted by a signal, fail with EINTR. */
FILE *
_Py_wfopen(const wchar_t *path, const wchar_t *mode)
{
    FILE *f;
    if (PySys_Audit("open", "uui", path, mode, 0) < 0) {
        return NULL;
    }
#ifndef MS_WINDOWS
    char *cpath;
    char cmode[10];
    size_t r;
    r = wcstombs(cmode, mode, 10);
    if (r == DECODE_ERROR || r >= 10) {
        errno = EINVAL;
        return NULL;
    }
    cpath = _Py_EncodeLocaleRaw(path, NULL);
    if (cpath == NULL) {
        return NULL;
    }
    f = fopen(cpath, cmode);
    PyMem_RawFree(cpath);
#else
    f = _wfopen(path, mode);
#endif
    if (f == NULL)
        return NULL;
    if (make_non_inheritable(fileno(f)) < 0) {
        fclose(f);
        return NULL;
    }
    return f;
}


/* Open a file. Call _wfopen() on Windows, or encode the path to the filesystem
   encoding and call fopen() otherwise.

   Return the new file object on success. Raise an exception and return NULL
   on error.

   The file descriptor is created non-inheritable.

   When interrupted by a signal (open() fails with EINTR), retry the syscall,
   except if the Python signal handler raises an exception.

   Release the GIL to call _wfopen() or fopen(). The caller must hold
   the GIL. */
FILE*
_Py_fopen_obj(PyObject *path, const char *mode)
{
    FILE *f;
    int async_err = 0;
#ifdef MS_WINDOWS
    wchar_t wmode[10];
    int usize;

    assert(PyGILState_Check());

    if (PySys_Audit("open", "Osi", path, mode, 0) < 0) {
        return NULL;
    }
    if (!PyUnicode_Check(path)) {
        PyErr_Format(PyExc_TypeError,
                     "str file path expected under Windows, got %R",
                     Py_TYPE(path));
        return NULL;
    }
#if USE_UNICODE_WCHAR_CACHE
    const wchar_t *wpath = _PyUnicode_AsUnicode(path);
#else /* USE_UNICODE_WCHAR_CACHE */
    wchar_t *wpath = PyUnicode_AsWideCharString(path, NULL);
#endif /* USE_UNICODE_WCHAR_CACHE */
    if (wpath == NULL)
        return NULL;

    usize = MultiByteToWideChar(CP_ACP, 0, mode, -1,
                                wmode, Py_ARRAY_LENGTH(wmode));
    if (usize == 0) {
        PyErr_SetFromWindowsErr(0);
#if !USE_UNICODE_WCHAR_CACHE
        PyMem_Free(wpath);
#endif /* USE_UNICODE_WCHAR_CACHE */
        return NULL;
    }

    do {
        Py_BEGIN_ALLOW_THREADS
        f = _wfopen(wpath, wmode);
        Py_END_ALLOW_THREADS
    } while (f == NULL
             && errno == EINTR && !(async_err = PyErr_CheckSignals()));
#if !USE_UNICODE_WCHAR_CACHE
    PyMem_Free(wpath);
#endif /* USE_UNICODE_WCHAR_CACHE */
#else
    PyObject *bytes;
    const char *path_bytes;

    assert(PyGILState_Check());

    if (!PyUnicode_FSConverter(path, &bytes))
        return NULL;
    path_bytes = PyBytes_AS_STRING(bytes);

    if (PySys_Audit("open", "Osi", path, mode, 0) < 0) {
        Py_DECREF(bytes);
        return NULL;
    }

    do {
        Py_BEGIN_ALLOW_THREADS
        f = fopen(path_bytes, mode);
        Py_END_ALLOW_THREADS
    } while (f == NULL
             && errno == EINTR && !(async_err = PyErr_CheckSignals()));

    Py_DECREF(bytes);
#endif
    if (async_err)
        return NULL;

    if (f == NULL) {
        PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
        return NULL;
    }

    if (set_inheritable(fileno(f), 0, 1, NULL) < 0) {
        fclose(f);
        return NULL;
    }
    return f;
}

/* Read count bytes from fd into buf.

   On success, return the number of read bytes, it can be lower than count.
   If the current file offset is at or past the end of file, no bytes are read,
   and read() returns zero.

   On error, raise an exception, set errno and return -1.

   When interrupted by a signal (read() fails with EINTR), retry the syscall.
   If the Python signal handler raises an exception, the function returns -1
   (the syscall is not retried).

   Release the GIL to call read(). The caller must hold the GIL. */
Py_ssize_t
_Py_read(int fd, void *buf, size_t count)
{
    Py_ssize_t n;
    int err;
    int async_err = 0;

    assert(PyGILState_Check());

    /* _Py_read() must not be called with an exception set, otherwise the
     * caller may think that read() was interrupted by a signal and the signal
     * handler raised an exception. */
    assert(!PyErr_Occurred());

    if (count > _PY_READ_MAX) {
        count = _PY_READ_MAX;
    }

    _Py_BEGIN_SUPPRESS_IPH
    do {
        Py_BEGIN_ALLOW_THREADS
        errno = 0;
#ifdef MS_WINDOWS
        n = read(fd, buf, (int)count);
#else
        n = read(fd, buf, count);
#endif
        /* save/restore errno because PyErr_CheckSignals()
         * and PyErr_SetFromErrno() can modify it */
        err = errno;
        Py_END_ALLOW_THREADS
    } while (n < 0 && err == EINTR &&
            !(async_err = PyErr_CheckSignals()));
    _Py_END_SUPPRESS_IPH

    if (async_err) {
        /* read() was interrupted by a signal (failed with EINTR)
         * and the Python signal handler raised an exception */
        errno = err;
        assert(errno == EINTR && PyErr_Occurred());
        return -1;
    }
    if (n < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        errno = err;
        return -1;
    }

    return n;
}

static Py_ssize_t
_Py_write_impl(int fd, const void *buf, size_t count, int gil_held)
{
    Py_ssize_t n;
    int err;
    int async_err = 0;

    _Py_BEGIN_SUPPRESS_IPH
#ifdef MS_WINDOWS
    if (count > 32767) {
        /* Issue #11395: the Windows console returns an error (12: not
           enough space error) on writing into stdout if stdout mode is
           binary and the length is greater than 66,000 bytes (or less,
           depending on heap usage). */
        if (gil_held) {
            Py_BEGIN_ALLOW_THREADS
            if (isatty(fd)) {
                count = 32767;
            }
            Py_END_ALLOW_THREADS
        } else {
            if (isatty(fd)) {
                count = 32767;
            }
        }
    }
#endif
    if (count > _PY_WRITE_MAX) {
        count = _PY_WRITE_MAX;
    }

    if (gil_held) {
        do {
            Py_BEGIN_ALLOW_THREADS
            errno = 0;
#ifdef MS_WINDOWS
            n = write(fd, buf, (int)count);
#else
            n = write(fd, buf, count);
#endif
            /* save/restore errno because PyErr_CheckSignals()
             * and PyErr_SetFromErrno() can modify it */
            err = errno;
            Py_END_ALLOW_THREADS
        } while (n < 0 && err == EINTR &&
                !(async_err = PyErr_CheckSignals()));
    }
    else {
        do {
            errno = 0;
#ifdef MS_WINDOWS
            n = write(fd, buf, (int)count);
#else
            n = write(fd, buf, count);
#endif
            err = errno;
        } while (n < 0 && err == EINTR);
    }
    _Py_END_SUPPRESS_IPH

    if (async_err) {
        /* write() was interrupted by a signal (failed with EINTR)
           and the Python signal handler raised an exception (if gil_held is
           nonzero). */
        errno = err;
        assert(errno == EINTR && (!gil_held || PyErr_Occurred()));
        return -1;
    }
    if (n < 0) {
        if (gil_held)
            PyErr_SetFromErrno(PyExc_OSError);
        errno = err;
        return -1;
    }

    return n;
}

/* Write count bytes of buf into fd.

   On success, return the number of written bytes, it can be lower than count
   including 0. On error, raise an exception, set errno and return -1.

   When interrupted by a signal (write() fails with EINTR), retry the syscall.
   If the Python signal handler raises an exception, the function returns -1
   (the syscall is not retried).

   Release the GIL to call write(). The caller must hold the GIL. */
Py_ssize_t
_Py_write(int fd, const void *buf, size_t count)
{
    assert(PyGILState_Check());

    /* _Py_write() must not be called with an exception set, otherwise the
     * caller may think that write() was interrupted by a signal and the signal
     * handler raised an exception. */
    assert(!PyErr_Occurred());

    return _Py_write_impl(fd, buf, count, 1);
}

/* Write count bytes of buf into fd.
 *
 * On success, return the number of written bytes, it can be lower than count
 * including 0. On error, set errno and return -1.
 *
 * When interrupted by a signal (write() fails with EINTR), retry the syscall
 * without calling the Python signal handler. */
Py_ssize_t
_Py_write_noraise(int fd, const void *buf, size_t count)
{
    return _Py_write_impl(fd, buf, count, 0);
}

#ifdef HAVE_READLINK

/* Read value of symbolic link. Encode the path to the locale encoding, decode
   the result from the locale encoding.

   Return -1 on encoding error, on readlink() error, if the internal buffer is
   too short, on decoding error, or if 'buf' is too short. */
int
_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t buflen)
{
    char *cpath;
    char cbuf[MAXPATHLEN];
    size_t cbuf_len = Py_ARRAY_LENGTH(cbuf);
    wchar_t *wbuf;
    Py_ssize_t res;
    size_t r1;

    cpath = _Py_EncodeLocaleRaw(path, NULL);
    if (cpath == NULL) {
        errno = EINVAL;
        return -1;
    }
    res = readlink(cpath, cbuf, cbuf_len);
    PyMem_RawFree(cpath);
    if (res == -1) {
        return -1;
    }
    if ((size_t)res == cbuf_len) {
        errno = EINVAL;
        return -1;
    }
    cbuf[res] = '\0'; /* buf will be null terminated */
    wbuf = Py_DecodeLocale(cbuf, &r1);
    if (wbuf == NULL) {
        errno = EINVAL;
        return -1;
    }
    /* wbuf must have space to store the trailing NUL character */
    if (buflen <= r1) {
        PyMem_RawFree(wbuf);
        errno = EINVAL;
        return -1;
    }
    wcsncpy(buf, wbuf, buflen);
    PyMem_RawFree(wbuf);
    return (int)r1;
}
#endif

#ifdef HAVE_REALPATH

/* Return the canonicalized absolute pathname. Encode path to the locale
   encoding, decode the result from the locale encoding.

   Return NULL on encoding error, realpath() error, decoding error
   or if 'resolved_path' is too short. */
wchar_t*
_Py_wrealpath(const wchar_t *path,
              wchar_t *resolved_path, size_t resolved_path_len)
{
    char *cpath;
    char cresolved_path[MAXPATHLEN];
    wchar_t *wresolved_path;
    char *res;
    size_t r;
    cpath = _Py_EncodeLocaleRaw(path, NULL);
    if (cpath == NULL) {
        errno = EINVAL;
        return NULL;
    }
    res = realpath(cpath, cresolved_path);
    PyMem_RawFree(cpath);
    if (res == NULL)
        return NULL;

    wresolved_path = Py_DecodeLocale(cresolved_path, &r);
    if (wresolved_path == NULL) {
        errno = EINVAL;
        return NULL;
    }
    /* wresolved_path must have space to store the trailing NUL character */
    if (resolved_path_len <= r) {
        PyMem_RawFree(wresolved_path);
        errno = EINVAL;
        return NULL;
    }
    wcsncpy(resolved_path, wresolved_path, resolved_path_len);
    PyMem_RawFree(wresolved_path);
    return resolved_path;
}
#endif


int
_Py_isabs(const wchar_t *path)
{
#ifdef MS_WINDOWS
    const wchar_t *tail;
    HRESULT hr = PathCchSkipRoot(path, &tail);
    if (FAILED(hr) || path == tail) {
        return 0;
    }
    if (tail == &path[1] && (path[0] == SEP || path[0] == ALTSEP)) {
        // Exclude paths with leading SEP
        return 0;
    }
    if (tail == &path[2] && path[1] == L':') {
        // Exclude drive-relative paths (e.g. C:filename.ext)
        return 0;
    }
    return 1;
#else
    return (path[0] == SEP);
#endif
}


/* Get an absolute path.
   On error (ex: fail to get the current directory), return -1.
   On memory allocation failure, set *abspath_p to NULL and return 0.
   On success, return a newly allocated to *abspath_p to and return 0.
   The string must be freed by PyMem_RawFree(). */
int
_Py_abspath(const wchar_t *path, wchar_t **abspath_p)
{
    if (path[0] == '\0' || !wcscmp(path, L".")) {
        wchar_t cwd[MAXPATHLEN + 1];
        cwd[Py_ARRAY_LENGTH(cwd) - 1] = 0;
        if (!_Py_wgetcwd(cwd, Py_ARRAY_LENGTH(cwd) - 1)) {
            /* unable to get the current directory */
            return -1;
        }
        *abspath_p = _PyMem_RawWcsdup(cwd);
        return 0;
    }

    if (_Py_isabs(path)) {
        *abspath_p = _PyMem_RawWcsdup(path);
        return 0;
    }

#ifdef MS_WINDOWS
    return _PyOS_getfullpathname(path, abspath_p);
#else
    wchar_t cwd[MAXPATHLEN + 1];
    cwd[Py_ARRAY_LENGTH(cwd) - 1] = 0;
    if (!_Py_wgetcwd(cwd, Py_ARRAY_LENGTH(cwd) - 1)) {
        /* unable to get the current directory */
        return -1;
    }

    size_t cwd_len = wcslen(cwd);
    size_t path_len = wcslen(path);
    size_t len = cwd_len + 1 + path_len + 1;
    if (len <= (size_t)PY_SSIZE_T_MAX / sizeof(wchar_t)) {
        *abspath_p = PyMem_RawMalloc(len * sizeof(wchar_t));
    }
    else {
        *abspath_p = NULL;
    }
    if (*abspath_p == NULL) {
        return 0;
    }

    wchar_t *abspath = *abspath_p;
    memcpy(abspath, cwd, cwd_len * sizeof(wchar_t));
    abspath += cwd_len;

    *abspath = (wchar_t)SEP;
    abspath++;

    memcpy(abspath, path, path_len * sizeof(wchar_t));
    abspath += path_len;

    *abspath = 0;
    return 0;
#endif
}


// The caller must ensure "buffer" is big enough.
static int
join_relfile(wchar_t *buffer, size_t bufsize,
             const wchar_t *dirname, const wchar_t *relfile)
{
#ifdef MS_WINDOWS
    if (FAILED(PathCchCombineEx(buffer, bufsize, dirname, relfile,
        PATHCCH_ALLOW_LONG_PATHS))) {
        return -1;
    }
#else
    assert(!_Py_isabs(relfile));
    size_t dirlen = wcslen(dirname);
    size_t rellen = wcslen(relfile);
    size_t maxlen = bufsize - 1;
    if (maxlen > MAXPATHLEN || dirlen >= maxlen || rellen >= maxlen - dirlen) {
        return -1;
    }
    if (dirlen == 0) {
        // We do not add a leading separator.
        wcscpy(buffer, relfile);
    }
    else {
        if (dirname != buffer) {
            wcscpy(buffer, dirname);
        }
        size_t relstart = dirlen;
        if (dirlen > 1 && dirname[dirlen - 1] != SEP) {
            buffer[dirlen] = SEP;
            relstart += 1;
        }
        wcscpy(&buffer[relstart], relfile);
    }
#endif
    return 0;
}

/* Join the two paths together, like os.path.join().  Return NULL
   if memory could not be allocated.  The caller is responsible
   for calling PyMem_RawFree() on the result. */
wchar_t *
_Py_join_relfile(const wchar_t *dirname, const wchar_t *relfile)
{
    assert(dirname != NULL && relfile != NULL);
#ifndef MS_WINDOWS
    assert(!_Py_isabs(relfile));
#endif
    size_t maxlen = wcslen(dirname) + 1 + wcslen(relfile);
    size_t bufsize = maxlen + 1;
    wchar_t *filename = PyMem_RawMalloc(bufsize * sizeof(wchar_t));
    if (filename == NULL) {
        return NULL;
    }
    assert(wcslen(dirname) < MAXPATHLEN);
    assert(wcslen(relfile) < MAXPATHLEN - wcslen(dirname));
    join_relfile(filename, bufsize, dirname, relfile);
    return filename;
}

/* Join the two paths together, like os.path.join().
     dirname: the target buffer with the dirname already in place,
              including trailing NUL
     relfile: this must be a relative path
     bufsize: total allocated size of the buffer
   Return -1 if anything is wrong with the path lengths. */
int
_Py_add_relfile(wchar_t *dirname, const wchar_t *relfile, size_t bufsize)
{
    assert(dirname != NULL && relfile != NULL);
    assert(bufsize > 0);
    return join_relfile(dirname, bufsize, dirname, relfile);
}


size_t
_Py_find_basename(const wchar_t *filename)
{
    for (size_t i = wcslen(filename); i > 0; --i) {
        if (filename[i] == SEP) {
            return i + 1;
        }
    }
    return 0;
}

/* In-place path normalisation. Returns the start of the normalized
   path, which will be within the original buffer. Guaranteed to not
   make the path longer, and will not fail. 'size' is the length of
   the path, if known. If -1, the first null character will be assumed
   to be the end of the path. */
wchar_t *
_Py_normpath(wchar_t *path, Py_ssize_t size)
{
    if (!path[0] || size == 0) {
        return path;
    }
    wchar_t *pEnd = size >= 0 ? &path[size] : NULL;
    wchar_t *p1 = path;     // sequentially scanned address in the path
    wchar_t *p2 = path;     // destination of a scanned character to be ljusted
    wchar_t *minP2 = path;  // the beginning of the destination range
    wchar_t lastC = L'\0';  // the last ljusted character, p2[-1] in most cases

#define IS_END(x) (pEnd ? (x) == pEnd : !*(x))
#ifdef ALTSEP
#define IS_SEP(x) (*(x) == SEP || *(x) == ALTSEP)
#else
#define IS_SEP(x) (*(x) == SEP)
#endif
#define SEP_OR_END(x) (IS_SEP(x) || IS_END(x))

    // Skip leading '.\'
    if (p1[0] == L'.' && IS_SEP(&p1[1])) {
        path = &path[2];
        while (IS_SEP(path) && !IS_END(path)) {
            path++;
        }
        p1 = p2 = minP2 = path;
        lastC = SEP;
    }
#ifdef MS_WINDOWS
    // Skip past drive segment and update minP2
    else if (p1[0] && p1[1] == L':') {
        *p2++ = *p1++;
        *p2++ = *p1++;
        minP2 = p2;
        lastC = L':';
    }
    // Skip past all \\-prefixed paths, including \\?\, \\.\,
    // and network paths, including the first segment.
    else if (IS_SEP(&p1[0]) && IS_SEP(&p1[1])) {
        int sepCount = 2;
        *p2++ = SEP;
        *p2++ = SEP;
        p1 += 2;
        for (; !IS_END(p1) && sepCount; ++p1) {
            if (IS_SEP(p1)) {
                --sepCount;
                *p2++ = lastC = SEP;
            } else {
                *p2++ = lastC = *p1;
            }
        }
        if (sepCount) {
            minP2 = p2;      // Invalid path
        } else {
            minP2 = p2 - 1;  // Absolute path has SEP at minP2
        }
    }
#else
    // Skip past two leading SEPs
    else if (IS_SEP(&p1[0]) && IS_SEP(&p1[1]) && !IS_SEP(&p1[2])) {
        *p2++ = *p1++;
        *p2++ = *p1++;
        minP2 = p2 - 1;  // Absolute path has SEP at minP2
        lastC = SEP;
    }
#endif /* MS_WINDOWS */

    /* if pEnd is specified, check that. Else, check for null terminator */
    for (; !IS_END(p1); ++p1) {
        wchar_t c = *p1;
#ifdef ALTSEP
        if (c == ALTSEP) {
            c = SEP;
        }
#endif
        if (lastC == SEP) {
            if (c == L'.') {
                int sep_at_1 = SEP_OR_END(&p1[1]);
                int sep_at_2 = !sep_at_1 && SEP_OR_END(&p1[2]);
                if (sep_at_2 && p1[1] == L'.') {
                    wchar_t *p3 = p2;
                    while (p3 != minP2 && *--p3 == SEP) { }
                    while (p3 != minP2 && *(p3 - 1) != SEP) { --p3; }
                    if (p2 == minP2
                        || (p3[0] == L'.' && p3[1] == L'.' && IS_SEP(&p3[2])))
                    {
                        // Previous segment is also ../, so append instead.
                        // Relative path does not absorb ../ at minP2 as well.
                        *p2++ = L'.';
                        *p2++ = L'.';
                        lastC = L'.';
                    } else if (p3[0] == SEP) {
                        // Absolute path, so absorb segment
                        p2 = p3 + 1;
                    } else {
                        p2 = p3;
                    }
                    p1 += 1;
                } else if (sep_at_1) {
                } else {
                    *p2++ = lastC = c;
                }
            } else if (c == SEP) {
            } else {
                *p2++ = lastC = c;
            }
        } else {
            *p2++ = lastC = c;
        }
    }
    *p2 = L'\0';
    if (p2 != minP2) {
        while (--p2 != minP2 && *p2 == SEP) {
            *p2 = L'\0';
        }
    }
#undef SEP_OR_END
#undef IS_SEP
#undef IS_END
    return path;
}


/* Get the current directory. buflen is the buffer size in wide characters
   including the null character. Decode the path from the locale encoding.

   Return NULL on getcwd() error, on decoding error, or if 'buf' is
   too short. */
wchar_t*
_Py_wgetcwd(wchar_t *buf, size_t buflen)
{
#ifdef MS_WINDOWS
    int ibuflen = (int)Py_MIN(buflen, INT_MAX);
    return _wgetcwd(buf, ibuflen);
#else
    char fname[MAXPATHLEN];
    wchar_t *wname;
    size_t len;

    if (getcwd(fname, Py_ARRAY_LENGTH(fname)) == NULL)
        return NULL;
    wname = Py_DecodeLocale(fname, &len);
    if (wname == NULL)
        return NULL;
    /* wname must have space to store the trailing NUL character */
    if (buflen <= len) {
        PyMem_RawFree(wname);
        return NULL;
    }
    wcsncpy(buf, wname, buflen);
    PyMem_RawFree(wname);
    return buf;
#endif
}

/* Duplicate a file descriptor. The new file descriptor is created as
   non-inheritable. Return a new file descriptor on success, raise an OSError
   exception and return -1 on error.

   The GIL is released to call dup(). The caller must hold the GIL. */
int
_Py_dup(int fd)
{
#ifdef MS_WINDOWS
    HANDLE handle;
#endif

    assert(PyGILState_Check());

#ifdef MS_WINDOWS
    handle = _Py_get_osfhandle(fd);
    if (handle == INVALID_HANDLE_VALUE)
        return -1;

    Py_BEGIN_ALLOW_THREADS
    _Py_BEGIN_SUPPRESS_IPH
    fd = dup(fd);
    _Py_END_SUPPRESS_IPH
    Py_END_ALLOW_THREADS
    if (fd < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    if (_Py_set_inheritable(fd, 0, NULL) < 0) {
        _Py_BEGIN_SUPPRESS_IPH
        close(fd);
        _Py_END_SUPPRESS_IPH
        return -1;
    }
#elif defined(HAVE_FCNTL_H) && defined(F_DUPFD_CLOEXEC)
    Py_BEGIN_ALLOW_THREADS
    _Py_BEGIN_SUPPRESS_IPH
    fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
    _Py_END_SUPPRESS_IPH
    Py_END_ALLOW_THREADS
    if (fd < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

#elif HAVE_DUP
    Py_BEGIN_ALLOW_THREADS
    _Py_BEGIN_SUPPRESS_IPH
    fd = dup(fd);
    _Py_END_SUPPRESS_IPH
    Py_END_ALLOW_THREADS
    if (fd < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    if (_Py_set_inheritable(fd, 0, NULL) < 0) {
        _Py_BEGIN_SUPPRESS_IPH
        close(fd);
        _Py_END_SUPPRESS_IPH
        return -1;
    }
#else
    errno = ENOTSUP;
    PyErr_SetFromErrno(PyExc_OSError);
    return -1;
#endif
    return fd;
}

#ifndef MS_WINDOWS
/* Get the blocking mode of the file descriptor.
   Return 0 if the O_NONBLOCK flag is set, 1 if the flag is cleared,
   raise an exception and return -1 on error. */
int
_Py_get_blocking(int fd)
{
    int flags;
    _Py_BEGIN_SUPPRESS_IPH
    flags = fcntl(fd, F_GETFL, 0);
    _Py_END_SUPPRESS_IPH
    if (flags < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    return !(flags & O_NONBLOCK);
}

/* Set the blocking mode of the specified file descriptor.

   Set the O_NONBLOCK flag if blocking is False, clear the O_NONBLOCK flag
   otherwise.

   Return 0 on success, raise an exception and return -1 on error. */
int
_Py_set_blocking(int fd, int blocking)
{
/* bpo-41462: On VxWorks, ioctl(FIONBIO) only works on sockets.
   Use fcntl() instead. */
#if defined(HAVE_SYS_IOCTL_H) && defined(FIONBIO) && !defined(__VXWORKS__)
    int arg = !blocking;
    if (ioctl(fd, FIONBIO, &arg) < 0)
        goto error;
#else
    int flags, res;

    _Py_BEGIN_SUPPRESS_IPH
    flags = fcntl(fd, F_GETFL, 0);
    if (flags >= 0) {
        if (blocking)
            flags = flags & (~O_NONBLOCK);
        else
            flags = flags | O_NONBLOCK;

        res = fcntl(fd, F_SETFL, flags);
    } else {
        res = -1;
    }
    _Py_END_SUPPRESS_IPH

    if (res < 0)
        goto error;
#endif
    return 0;

error:
    PyErr_SetFromErrno(PyExc_OSError);
    return -1;
}
#else   /* MS_WINDOWS */
void*
_Py_get_osfhandle_noraise(int fd)
{
    void *handle;
    _Py_BEGIN_SUPPRESS_IPH
    handle = (void*)_get_osfhandle(fd);
    _Py_END_SUPPRESS_IPH
    return handle;
}

void*
_Py_get_osfhandle(int fd)
{
    void *handle = _Py_get_osfhandle_noraise(fd);
    if (handle == INVALID_HANDLE_VALUE)
        PyErr_SetFromErrno(PyExc_OSError);

    return handle;
}

int
_Py_open_osfhandle_noraise(void *handle, int flags)
{
    int fd;
    _Py_BEGIN_SUPPRESS_IPH
    fd = _open_osfhandle((intptr_t)handle, flags);
    _Py_END_SUPPRESS_IPH
    return fd;
}

int
_Py_open_osfhandle(void *handle, int flags)
{
    int fd = _Py_open_osfhandle_noraise(handle, flags);
    if (fd == -1)
        PyErr_SetFromErrno(PyExc_OSError);

    return fd;
}
#endif  /* MS_WINDOWS */

int
_Py_GetLocaleconvNumeric(struct lconv *lc,
                         PyObject **decimal_point, PyObject **thousands_sep)
{
    assert(decimal_point != NULL);
    assert(thousands_sep != NULL);

#ifndef MS_WINDOWS
    int change_locale = 0;
    if ((strlen(lc->decimal_point) > 1 || ((unsigned char)lc->decimal_point[0]) > 127)) {
        change_locale = 1;
    }
    if ((strlen(lc->thousands_sep) > 1 || ((unsigned char)lc->thousands_sep[0]) > 127)) {
        change_locale = 1;
    }

    /* Keep a copy of the LC_CTYPE locale */
    char *oldloc = NULL, *loc = NULL;
    if (change_locale) {
        oldloc = setlocale(LC_CTYPE, NULL);
        if (!oldloc) {
            PyErr_SetString(PyExc_RuntimeWarning,
                            "failed to get LC_CTYPE locale");
            return -1;
        }

        oldloc = _PyMem_Strdup(oldloc);
        if (!oldloc) {
            PyErr_NoMemory();
            return -1;
        }

        loc = setlocale(LC_NUMERIC, NULL);
        if (loc != NULL && strcmp(loc, oldloc) == 0) {
            loc = NULL;
        }

        if (loc != NULL) {
            /* Only set the locale temporarily the LC_CTYPE locale
               if LC_NUMERIC locale is different than LC_CTYPE locale and
               decimal_point and/or thousands_sep are non-ASCII or longer than
               1 byte */
            setlocale(LC_CTYPE, loc);
        }
    }

#define GET_LOCALE_STRING(ATTR) PyUnicode_DecodeLocale(lc->ATTR, NULL)
#else /* MS_WINDOWS */
/* Use _W_* fields of Windows strcut lconv */
#define GET_LOCALE_STRING(ATTR) PyUnicode_FromWideChar(lc->_W_ ## ATTR, -1)
#endif /* MS_WINDOWS */

    int res = -1;

    *decimal_point = GET_LOCALE_STRING(decimal_point);
    if (*decimal_point == NULL) {
        goto done;
    }

    *thousands_sep = GET_LOCALE_STRING(thousands_sep);
    if (*thousands_sep == NULL) {
        goto done;
    }

    res = 0;

done:
#ifndef MS_WINDOWS
    if (loc != NULL) {
        setlocale(LC_CTYPE, oldloc);
    }
    PyMem_Free(oldloc);
#endif
    return res;

#undef GET_LOCALE_STRING
}

/* Our selection logic for which function to use is as follows:
 * 1. If close_range(2) is available, always prefer that; it's better for
 *    contiguous ranges like this than fdwalk(3) which entails iterating over
 *    the entire fd space and simply doing nothing for those outside the range.
 * 2. If closefrom(2) is available, we'll attempt to use that next if we're
 *    closing up to sysconf(_SC_OPEN_MAX).
 * 2a. Fallback to fdwalk(3) if we're not closing up to sysconf(_SC_OPEN_MAX),
 *    as that will be more performant if the range happens to have any chunk of
 *    non-opened fd in the middle.
 * 2b. If fdwalk(3) isn't available, just do a plain close(2) loop.
 */
#ifdef __FreeBSD__
#  define USE_CLOSEFROM
#endif /* __FreeBSD__ */

#ifdef HAVE_FDWALK
#  define USE_FDWALK
#endif /* HAVE_FDWALK */

#ifdef USE_FDWALK
static int
_fdwalk_close_func(void *lohi, int fd)
{
    int lo = ((int *)lohi)[0];
    int hi = ((int *)lohi)[1];

    if (fd >= hi) {
        return 1;
    }
    else if (fd >= lo) {
        /* Ignore errors */
        (void)close(fd);
    }
    return 0;
}
#endif /* USE_FDWALK */

/* Closes all file descriptors in [first, last], ignoring errors. */
void
_Py_closerange(int first, int last)
{
    first = Py_MAX(first, 0);
    _Py_BEGIN_SUPPRESS_IPH
#ifdef HAVE_CLOSE_RANGE
    if (close_range(first, last, 0) == 0) {
        /* close_range() ignores errors when it closes file descriptors.
         * Possible reasons of an error return are lack of kernel support
         * or denial of the underlying syscall by a seccomp sandbox on Linux.
         * Fallback to other methods in case of any error. */
    }
    else
#endif /* HAVE_CLOSE_RANGE */
#ifdef USE_CLOSEFROM
    if (last >= sysconf(_SC_OPEN_MAX)) {
        /* Any errors encountered while closing file descriptors are ignored */
        closefrom(first);
    }
    else
#endif /* USE_CLOSEFROM */
#ifdef USE_FDWALK
    {
        int lohi[2];
        lohi[0] = first;
        lohi[1] = last + 1;
        fdwalk(_fdwalk_close_func, lohi);
    }
#else
    {
        for (int i = first; i <= last; i++) {
            /* Ignore errors */
            (void)close(i);
        }
    }
#endif /* USE_FDWALK */
    _Py_END_SUPPRESS_IPH
}