File: extract.c

package info (click to toggle)
tar 1.27.1-2+deb8u1
  • links: PTS, VCS
  • area: main
  • in suites: jessie
  • size: 16,180 kB
  • ctags: 8,190
  • sloc: sh: 40,042; ansic: 22,145; yacc: 1,252; makefile: 432; sed: 16
file content (1781 lines) | stat: -rw-r--r-- 48,081 bytes parent folder | download
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
/* Extract files from a tar archive.

   Copyright 1988, 1992-1994, 1996-2001, 2003-2007, 2010, 2012-2013
   Free Software Foundation, Inc.

   This file is part of GNU tar.

   GNU tar is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   GNU tar is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

   Written by John Gilmore, on 1985-11-19.  */

#include <system.h>
#include <quotearg.h>
#include <errno.h>
#include <priv-set.h>
#include <root-uid.h>
#include <utimens.h>

#include "common.h"

static bool we_are_root;	/* true if our effective uid == 0 */
static mode_t newdir_umask;	/* umask when creating new directories */
static mode_t current_umask;	/* current umask (which is set to 0 if -p) */

#define ALL_MODE_BITS ((mode_t) ~ (mode_t) 0)

#if ! HAVE_FCHMOD && ! defined fchmod
# define fchmod(fd, mode) (errno = ENOSYS, -1)
#endif
#if ! HAVE_FCHOWN && ! defined fchown
# define fchown(fd, uid, gid) (errno = ENOSYS, -1)
#endif

/* Return true if an error number ERR means the system call is
   supported in this case.  */
static bool
implemented (int err)
{
  return ! (err == ENOSYS
	    || err == ENOTSUP
	    || (EOPNOTSUPP != ENOTSUP && err == EOPNOTSUPP));
}

/* List of directories whose statuses we need to extract after we've
   finished extracting their subsidiary files.  If you consider each
   contiguous subsequence of elements of the form [D]?[^D]*, where [D]
   represents an element where AFTER_LINKS is nonzero and [^D]
   represents an element where AFTER_LINKS is zero, then the head
   of the subsequence has the longest name, and each non-head element
   in the prefix is an ancestor (in the directory hierarchy) of the
   preceding element.  */

struct delayed_set_stat
  {
    /* Next directory in list.  */
    struct delayed_set_stat *next;

    /* Metadata for this directory.  */
    dev_t dev;
    ino_t ino;
    mode_t mode; /* The desired mode is MODE & ~ current_umask.  */
    uid_t uid;
    gid_t gid;
    struct timespec atime;
    struct timespec mtime;

    /* An estimate of the directory's current mode, along with a mask
       specifying which bits of this estimate are known to be correct.
       If CURRENT_MODE_MASK is zero, CURRENT_MODE's value doesn't
       matter.  */
    mode_t current_mode;
    mode_t current_mode_mask;

    /* This directory is an intermediate directory that was created
       as an ancestor of some other directory; it was not mentioned
       in the archive, so do not set its uid, gid, atime, or mtime,
       and don't alter its mode outside of MODE_RWX.  */
    bool interdir;

    /* Whether symbolic links should be followed when accessing the
       directory.  */
    int atflag;

    /* Do not set the status of this directory until after delayed
       links are created.  */
    bool after_links;

    /* Directory that the name is relative to.  */
    int change_dir;

    /* extended attributes*/
    char *cntx_name;
    char *acls_a_ptr;
    size_t acls_a_len;
    char *acls_d_ptr;
    size_t acls_d_len;
    size_t xattr_map_size;
    struct xattr_array *xattr_map;
    /* Length and contents of name.  */
    size_t file_name_len;
    char file_name[1];
  };

static struct delayed_set_stat *delayed_set_stat_head;

/* List of links whose creation we have delayed.  */
struct delayed_link
  {
    /* The next delayed link in the list.  */
    struct delayed_link *next;

    /* The device, inode number and birthtime of the placeholder.
       birthtime.tv_nsec is negative if the birthtime is not available.
       Don't use mtime as this would allow for false matches if some
       other process removes the placeholder.  Don't use ctime as
       this would cause race conditions and other screwups, e.g.,
       when restoring hard-linked symlinks.  */
    dev_t dev;
    ino_t ino;
    struct timespec birthtime;

    /* True if the link is symbolic.  */
    bool is_symlink;

    /* The desired metadata, valid only the link is symbolic.  */
    mode_t mode;
    uid_t uid;
    gid_t gid;
    struct timespec atime;
    struct timespec mtime;

    /* The directory that the sources and target are relative to.  */
    int change_dir;

    /* A list of sources for this link.  The sources are all to be
       hard-linked together.  */
    struct string_list *sources;

    /* SELinux context */
    char *cntx_name;

    /* ACLs */
    char *acls_a_ptr;
    size_t acls_a_len;
    char *acls_d_ptr;
    size_t acls_d_len;

    size_t xattr_map_size;
    struct xattr_array *xattr_map;

    /* The desired target of the desired link.  */
    char target[1];
  };

static struct delayed_link *delayed_link_head;

struct string_list
  {
    struct string_list *next;
    char string[1];
  };

/*  Set up to extract files.  */
void
extr_init (void)
{
  we_are_root = geteuid () == ROOT_UID;
  same_permissions_option += we_are_root;
  same_owner_option += we_are_root;

  /* Option -p clears the kernel umask, so it does not affect proper
     restoration of file permissions.  New intermediate directories will
     comply with umask at start of program.  */

  newdir_umask = umask (0);
  if (0 < same_permissions_option)
    current_umask = 0;
  else
    {
      umask (newdir_umask);	/* restore the kernel umask */
      current_umask = newdir_umask;
    }
}

/* Use fchmod if possible, fchmodat otherwise.  */
static int
fd_chmod (int fd, char const *file, mode_t mode, int atflag)
{
  if (0 <= fd)
    {
      int result = fchmod (fd, mode);
      if (result == 0 || implemented (errno))
	return result;
    }
  return fchmodat (chdir_fd, file, mode, atflag);
}

/* Use fchown if possible, fchownat otherwise.  */
static int
fd_chown (int fd, char const *file, uid_t uid, gid_t gid, int atflag)
{
  if (0 <= fd)
    {
      int result = fchown (fd, uid, gid);
      if (result == 0 || implemented (errno))
	return result;
    }
  return fchownat (chdir_fd, file, uid, gid, atflag);
}

/* Use fstat if possible, fstatat otherwise.  */
static int
fd_stat (int fd, char const *file, struct stat *st, int atflag)
{
  return (0 <= fd
	  ? fstat (fd, st)
	  : fstatat (chdir_fd, file, st, atflag));
}

/* Set the mode for FILE_NAME to MODE.
   MODE_MASK specifies the bits of MODE that we care about;
   thus if MODE_MASK is zero, do nothing.
   If FD is nonnegative, it is a file descriptor for the file.
   CURRENT_MODE and CURRENT_MODE_MASK specify information known about
   the file's current mode, using the style of struct delayed_set_stat.
   TYPEFLAG specifies the type of the file.
   ATFLAG specifies the flag to use when statting the file.  */
static void
set_mode (char const *file_name,
	  mode_t mode, mode_t mode_mask, int fd,
	  mode_t current_mode, mode_t current_mode_mask,
	  char typeflag, int atflag)
{
  if (((current_mode ^ mode) | ~ current_mode_mask) & mode_mask)
    {
      if (MODE_ALL & ~ mode_mask & ~ current_mode_mask)
	{
	  struct stat st;
	  if (fd_stat (fd, file_name, &st, atflag) != 0)
	    {
	      stat_error (file_name);
	      return;
	    }
	  current_mode = st.st_mode;
	}

      current_mode &= MODE_ALL;
      mode = (current_mode & ~ mode_mask) | (mode & mode_mask);

      if (current_mode != mode)
	{
	  int chmod_errno =
	    fd_chmod (fd, file_name, mode, atflag) == 0 ? 0 : errno;

	  /* On Solaris, chmod may fail if we don't have PRIV_ALL, because
	     setuid-root files would otherwise be a backdoor.  See
	     http://opensolaris.org/jive/thread.jspa?threadID=95826
	     (2009-09-03).  */
	  if (chmod_errno == EPERM && (mode & S_ISUID)
	      && priv_set_restore_linkdir () == 0)
	    {
	      chmod_errno =
		fd_chmod (fd, file_name, mode, atflag) == 0 ? 0 : errno;
	      priv_set_remove_linkdir ();
	    }

	  /* Linux fchmodat does not support AT_SYMLINK_NOFOLLOW, and
	     returns ENOTSUP even when operating on non-symlinks, try
	     again with the flag disabled if it does not appear to be
	     supported and if the file is not a symlink.  This
	     introduces a race, alas.  */
	  if (atflag && typeflag != SYMTYPE && ! implemented (chmod_errno))
	    chmod_errno = fd_chmod (fd, file_name, mode, 0) == 0 ? 0 : errno;

	  if (chmod_errno
	      && (typeflag != SYMTYPE || implemented (chmod_errno)))
	    {
	      errno = chmod_errno;
	      chmod_error_details (file_name, mode);
	    }
	}
    }
}

/* Check time after successfully setting FILE_NAME's time stamp to T.  */
static void
check_time (char const *file_name, struct timespec t)
{
  if (t.tv_sec < 0)
    WARNOPT (WARN_TIMESTAMP,
	     (0, 0, _("%s: implausibly old time stamp %s"),
	      file_name, tartime (t, true)));
  else if (timespec_cmp (volume_start_time, t) < 0)
    {
      struct timespec now;
      gettime (&now);
      if (timespec_cmp (now, t) < 0)
	{
	  char buf[TIMESPEC_STRSIZE_BOUND];
	  struct timespec diff;
	  diff.tv_sec = t.tv_sec - now.tv_sec;
	  diff.tv_nsec = t.tv_nsec - now.tv_nsec;
	  if (diff.tv_nsec < 0)
	    {
	      diff.tv_nsec += BILLION;
	      diff.tv_sec--;
	    }
	  WARNOPT (WARN_TIMESTAMP,
		   (0, 0, _("%s: time stamp %s is %s s in the future"),
		    file_name, tartime (t, true), code_timespec (diff, buf)));
	}
    }
}

/* Restore stat attributes (owner, group, mode and times) for
   FILE_NAME, using information given in *ST.
   If FD is nonnegative, it is a file descriptor for the file.
   CURRENT_MODE and CURRENT_MODE_MASK specify information known about
   the file's current mode, using the style of struct delayed_set_stat.
   TYPEFLAG specifies the type of the file.
   If INTERDIR, this is an intermediate directory.
   ATFLAG specifies the flag to use when statting the file.  */

static void
set_stat (char const *file_name,
	  struct tar_stat_info const *st,
	  int fd, mode_t current_mode, mode_t current_mode_mask,
	  char typeflag, bool interdir, int atflag)
{
  /* Do the utime before the chmod because some versions of utime are
     broken and trash the modes of the file.  */

  if (! touch_option && ! interdir)
    {
      struct timespec ts[2];
      if (incremental_option)
	ts[0] = st->atime;
      else
	ts[0].tv_nsec = UTIME_OMIT;
      ts[1] = st->mtime;

      if (fdutimensat (fd, chdir_fd, file_name, ts, atflag) == 0)
	{
	  if (incremental_option)
	    check_time (file_name, ts[0]);
	  check_time (file_name, ts[1]);
	}
      else if (typeflag != SYMTYPE || implemented (errno))
	utime_error (file_name);
    }

  if (0 < same_owner_option && ! interdir)
    {
      /* Some systems allow non-root users to give files away.  Once this
	 done, it is not possible anymore to change file permissions.
	 However, setting file permissions now would be incorrect, since
	 they would apply to the wrong user, and there would be a race
	 condition.  So, don't use systems that allow non-root users to
	 give files away.  */
      uid_t uid = st->stat.st_uid;
      gid_t gid = st->stat.st_gid;

      if (fd_chown (fd, file_name, uid, gid, atflag) == 0)
	{
	  /* Changing the owner can clear st_mode bits in some cases.  */
	  if ((current_mode | ~ current_mode_mask) & S_IXUGO)
	    current_mode_mask &= ~ (current_mode & (S_ISUID | S_ISGID));
	}
      else if (typeflag != SYMTYPE || implemented (errno))
	chown_error_details (file_name, uid, gid);
    }

  set_mode (file_name,
	    st->stat.st_mode & ~ current_umask,
	    0 < same_permissions_option && ! interdir ? MODE_ALL : MODE_RWX,
	    fd, current_mode, current_mode_mask, typeflag, atflag);

  /* these three calls must be done *after* fd_chown() call because fd_chown
     causes that linux capabilities becomes cleared. */
  xattrs_xattrs_set (st, file_name, typeflag, 1);
  xattrs_acls_set (st, file_name, typeflag);
  xattrs_selinux_set (st, file_name, typeflag);
}

/* For each entry H in the leading prefix of entries in HEAD that do
   not have after_links marked, mark H and fill in its dev and ino
   members.  Assume HEAD && ! HEAD->after_links.  */
static void
mark_after_links (struct delayed_set_stat *head)
{
  struct delayed_set_stat *h = head;

  do
    {
      struct stat st;
      h->after_links = 1;

      if (deref_stat (h->file_name, &st) != 0)
	stat_error (h->file_name);
      else
	{
	  h->dev = st.st_dev;
	  h->ino = st.st_ino;
	}
    }
  while ((h = h->next) && ! h->after_links);
}

/* Remember to restore stat attributes (owner, group, mode and times)
   for the directory FILE_NAME, using information given in *ST,
   once we stop extracting files into that directory.

   If ST is null, merely create a placeholder node for an intermediate
   directory that was created by make_directories.

   NOTICE: this works only if the archive has usual member order, i.e.
   directory, then the files in that directory. Incremental archive have
   somewhat reversed order: first go subdirectories, then all other
   members. To help cope with this case the variable
   delay_directory_restore_option is set by prepare_to_extract.

   If an archive was explicitely created so that its member order is
   reversed, some directory timestamps can be restored incorrectly,
   e.g.:
       tar --no-recursion -cf archive dir dir/file1 foo dir/file2
*/
static void
delay_set_stat (char const *file_name, struct tar_stat_info const *st,
		mode_t current_mode, mode_t current_mode_mask,
		mode_t mode, int atflag)
{
  size_t file_name_len = strlen (file_name);
  struct delayed_set_stat *data =
    xmalloc (offsetof (struct delayed_set_stat, file_name)
	     + file_name_len + 1);
  data->next = delayed_set_stat_head;
  data->mode = mode;
  if (st)
    {
      data->dev = st->stat.st_dev;
      data->ino = st->stat.st_ino;
      data->uid = st->stat.st_uid;
      data->gid = st->stat.st_gid;
      data->atime = st->atime;
      data->mtime = st->mtime;
    }
  data->file_name_len = file_name_len;
  data->current_mode = current_mode;
  data->current_mode_mask = current_mode_mask;
  data->interdir = ! st;
  data->atflag = atflag;
  data->after_links = 0;
  data->change_dir = chdir_current;
  data->cntx_name = NULL;
  if (st)
    assign_string (&data->cntx_name, st->cntx_name);
  if (st && st->acls_a_ptr)
    {
      data->acls_a_ptr = xmemdup (st->acls_a_ptr, st->acls_a_len + 1);
      data->acls_a_len = st->acls_a_len;
    }
  else
    {
      data->acls_a_ptr = NULL;
      data->acls_a_len = 0;
    }
  if (st && st->acls_d_ptr)
    {
      data->acls_d_ptr = xmemdup (st->acls_d_ptr, st->acls_d_len + 1);
      data->acls_d_len = st->acls_d_len;
    }
  else
    {
      data->acls_d_ptr = NULL;
      data->acls_d_len = 0;
    }
  if (st)
    xheader_xattr_copy (st, &data->xattr_map, &data->xattr_map_size);
  else
    {
      data->xattr_map = NULL;
      data->xattr_map_size = 0;
    }
  strcpy (data->file_name, file_name);
  delayed_set_stat_head = data;
  if (must_be_dot_or_slash (file_name))
    mark_after_links (data);
}

/* Update the delayed_set_stat info for an intermediate directory
   created within the file name of DIR.  The intermediate directory turned
   out to be the same as this directory, e.g. due to ".." or symbolic
   links.  *DIR_STAT_INFO is the status of the directory.  */
static void
repair_delayed_set_stat (char const *dir,
			 struct stat const *dir_stat_info)
{
  struct delayed_set_stat *data;
  for (data = delayed_set_stat_head;  data;  data = data->next)
    {
      struct stat st;
      if (fstatat (chdir_fd, data->file_name, &st, data->atflag) != 0)
	{
	  stat_error (data->file_name);
	  return;
	}

      if (st.st_dev == dir_stat_info->st_dev
	  && st.st_ino == dir_stat_info->st_ino)
	{
	  data->dev = current_stat_info.stat.st_dev;
	  data->ino = current_stat_info.stat.st_ino;
	  data->mode = current_stat_info.stat.st_mode;
	  data->uid = current_stat_info.stat.st_uid;
	  data->gid = current_stat_info.stat.st_gid;
	  data->atime = current_stat_info.atime;
	  data->mtime = current_stat_info.mtime;
	  data->current_mode = st.st_mode;
	  data->current_mode_mask = ALL_MODE_BITS;
	  data->interdir = false;
	  return;
	}
    }

  ERROR ((0, 0, _("%s: Unexpected inconsistency when making directory"),
	  quotearg_colon (dir)));
}

/* After a file/link/directory creation has failed, see if
   it's because some required directory was not present, and if so,
   create all required directories.  Return zero if all the required
   directories were created, nonzero (issuing a diagnostic) otherwise.
   Set *INTERDIR_MADE if at least one directory was created.  */
static int
make_directories (char *file_name, bool *interdir_made)
{
  char *cursor0 = file_name + FILE_SYSTEM_PREFIX_LEN (file_name);
  char *cursor;	        	/* points into the file name */

  for (cursor = cursor0; *cursor; cursor++)
    {
      mode_t mode;
      mode_t desired_mode;
      int status;

      if (! ISSLASH (*cursor))
	continue;

      /* Avoid mkdir of empty string, if leading or double '/'.  */

      if (cursor == cursor0 || ISSLASH (cursor[-1]))
	continue;

      /* Avoid mkdir where last part of file name is "." or "..".  */

      if (cursor[-1] == '.'
	  && (cursor == cursor0 + 1 || ISSLASH (cursor[-2])
	      || (cursor[-2] == '.'
		  && (cursor == cursor0 + 2 || ISSLASH (cursor[-3])))))
	continue;

      *cursor = '\0';		/* truncate the name there */
      desired_mode = MODE_RWX & ~ newdir_umask;
      mode = desired_mode | (we_are_root ? 0 : MODE_WXUSR);
      status = mkdirat (chdir_fd, file_name, mode);

      if (status == 0)
	{
	  /* Create a struct delayed_set_stat even if
	     mode == desired_mode, because
	     repair_delayed_set_stat may need to update the struct.  */
	  delay_set_stat (file_name,
			  0, mode & ~ current_umask, MODE_RWX,
			  desired_mode, AT_SYMLINK_NOFOLLOW);

	  print_for_mkdir (file_name, cursor - file_name, desired_mode);
	  *interdir_made = true;
	}
      else if (errno == EEXIST)
	status = 0;
      else
	{
	  /* Check whether the desired file exists.  Even when the
	     file exists, mkdir can fail with some errno value E other
	     than EEXIST, so long as E describes an error condition
	     that also applies.  */
	  int e = errno;
	  struct stat st;
	  status = fstatat (chdir_fd, file_name, &st, 0);
	  if (status)
	    {
	      errno = e;
	      mkdir_error (file_name);
	    }
	}

      *cursor = '/';
      if (status)
	return status;
    }

  return 0;
}

/* Return true if FILE_NAME (with status *STP, if STP) is not a
   directory, and has a time stamp newer than (or equal to) that of
   TAR_STAT.  */
static bool
file_newer_p (const char *file_name, struct stat const *stp,
	      struct tar_stat_info *tar_stat)
{
  struct stat st;

  if (!stp)
    {
      if (deref_stat (file_name, &st) != 0)
	{
	  if (errno != ENOENT)
	    {
	      stat_warn (file_name);
	      /* Be safer: if the file exists, assume it is newer.  */
	      return true;
	    }
	  return false;
	}
      stp = &st;
    }

  return (! S_ISDIR (stp->st_mode)
	  && tar_timespec_cmp (tar_stat->mtime, get_stat_mtime (stp)) <= 0);
}

#define RECOVER_NO 0
#define RECOVER_OK 1
#define RECOVER_SKIP 2

/* Attempt repairing what went wrong with the extraction.  Delete an
   already existing file or create missing intermediate directories.
   Return RECOVER_OK if we somewhat increased our chances at a successful
   extraction, RECOVER_NO if there are no chances, and RECOVER_SKIP if the
   caller should skip extraction of that member.  The value of errno is
   properly restored on returning RECOVER_NO.

   If REGULAR, the caller was trying to extract onto a regular file.

   Set *INTERDIR_MADE if an intermediate directory is made as part of
   the recovery process.  */

static int
maybe_recoverable (char *file_name, bool regular, bool *interdir_made)
{
  int e = errno;
  struct stat st;
  struct stat const *stp = 0;

  if (*interdir_made)
    return RECOVER_NO;

  switch (e)
    {
    case ELOOP:

      /* With open ("symlink", O_NOFOLLOW|...), POSIX says errno == ELOOP,
	 but some operating systems do not conform to the standard.  */
#ifdef EFTYPE
      /* NetBSD uses errno == EFTYPE; see <http://gnats.netbsd.org/43154>.  */
    case EFTYPE:
#endif
      /* FreeBSD 8.1 uses errno == EMLINK.  */
    case EMLINK:
      /* Tru64 5.1B uses errno == ENOTSUP.  */
    case ENOTSUP:

      if (! regular
	  || old_files_option != OVERWRITE_OLD_FILES || dereference_option)
	break;
      if (strchr (file_name, '/'))
	{
	  if (deref_stat (file_name, &st) != 0)
	    break;
	  stp = &st;
	}

      /* The caller tried to open a symbolic link with O_NOFOLLOW.
	 Fall through, treating it as an already-existing file.  */

    case EEXIST:
      /* Remove an old file, if the options allow this.  */

      switch (old_files_option)
	{
	case SKIP_OLD_FILES:
	  WARNOPT (WARN_EXISTING_FILE,
		   (0, 0, _("%s: skipping existing file"), file_name));
	  return RECOVER_SKIP;

	case KEEP_OLD_FILES:
	  return RECOVER_NO;

	case KEEP_NEWER_FILES:
	  if (file_newer_p (file_name, stp, &current_stat_info))
	    break;
	  /* FALL THROUGH */

	case DEFAULT_OLD_FILES:
	case NO_OVERWRITE_DIR_OLD_FILES:
	case OVERWRITE_OLD_FILES:
	  if (0 < remove_any_file (file_name, ORDINARY_REMOVE_OPTION))
	    return RECOVER_OK;
	  break;

	case UNLINK_FIRST_OLD_FILES:
	  break;
	}

    case ENOENT:
      /* Attempt creating missing intermediate directories.  */
      if (make_directories (file_name, interdir_made) == 0 && *interdir_made)
	return RECOVER_OK;
      break;

    default:
      /* Just say we can't do anything about it...  */
      break;
    }

  errno = e;
  return RECOVER_NO;
}

/* Restore stat extended attributes (xattr) for FILE_NAME, using information
   given in *ST.  Restore before extraction because they may affect file layout
   (e.g. on Lustre distributed parallel filesystem - setting info about how many
   servers is this file striped over, stripe size, mirror copies, etc.
   in advance dramatically improves the following  performance of reading and
   writing a file).  If not restoring permissions, invert the INVERT_PERMISSIONS
   bits from the file's current permissions.  TYPEFLAG specifies the type of the
   file.  FILE_CREATED indicates set_xattr has created the file */
static int
set_xattr (char const *file_name, struct tar_stat_info const *st,
           mode_t invert_permissions, char typeflag, int *file_created)
{
  int status = 0;

#ifdef HAVE_XATTRS
  bool interdir_made = false;

  if ((xattrs_option > 0) && st->xattr_map_size)
    {
      mode_t mode = current_stat_info.stat.st_mode & MODE_RWX & ~ current_umask;

      do
        status = mknodat (chdir_fd, file_name, mode ^ invert_permissions, 0);
      while (status && maybe_recoverable ((char *)file_name, false,
                                          &interdir_made));

      xattrs_xattrs_set (st, file_name, typeflag, 0);
      *file_created = 1;
    }
#endif

  return(status);
}

/* Fix the statuses of all directories whose statuses need fixing, and
   which are not ancestors of FILE_NAME.  If AFTER_LINKS is
   nonzero, do this for all such directories; otherwise, stop at the
   first directory that is marked to be fixed up only after delayed
   links are applied.  */
static void
apply_nonancestor_delayed_set_stat (char const *file_name, bool after_links)
{
  size_t file_name_len = strlen (file_name);
  bool check_for_renamed_directories = 0;

  while (delayed_set_stat_head)
    {
      struct delayed_set_stat *data = delayed_set_stat_head;
      bool skip_this_one = 0;
      struct stat st;
      mode_t current_mode = data->current_mode;
      mode_t current_mode_mask = data->current_mode_mask;

      check_for_renamed_directories |= data->after_links;

      if (after_links < data->after_links
	  || (data->file_name_len < file_name_len
	      && file_name[data->file_name_len]
	      && (ISSLASH (file_name[data->file_name_len])
		  || ISSLASH (file_name[data->file_name_len - 1]))
	      && memcmp (file_name, data->file_name, data->file_name_len) == 0))
	break;

      chdir_do (data->change_dir);

      if (check_for_renamed_directories)
	{
	  if (fstatat (chdir_fd, data->file_name, &st, data->atflag) != 0)
	    {
	      stat_error (data->file_name);
	      skip_this_one = 1;
	    }
	  else
	    {
	      current_mode = st.st_mode;
	      current_mode_mask = ALL_MODE_BITS;
	      if (! (st.st_dev == data->dev && st.st_ino == data->ino))
		{
		  ERROR ((0, 0,
			  _("%s: Directory renamed before its status could be extracted"),
			  quotearg_colon (data->file_name)));
		  skip_this_one = 1;
		}
	    }
	}

      if (! skip_this_one)
	{
	  struct tar_stat_info sb;
	  sb.stat.st_mode = data->mode;
	  sb.stat.st_uid = data->uid;
	  sb.stat.st_gid = data->gid;
	  sb.atime = data->atime;
	  sb.mtime = data->mtime;
	  sb.cntx_name = data->cntx_name;
	  sb.acls_a_ptr = data->acls_a_ptr;
	  sb.acls_a_len = data->acls_a_len;
	  sb.acls_d_ptr = data->acls_d_ptr;
	  sb.acls_d_len = data->acls_d_len;
	  sb.xattr_map = data->xattr_map;
	  sb.xattr_map_size = data->xattr_map_size;
	  set_stat (data->file_name, &sb,
		    -1, current_mode, current_mode_mask,
		    DIRTYPE, data->interdir, data->atflag);
	}

      delayed_set_stat_head = data->next;
      xheader_xattr_free (data->xattr_map, data->xattr_map_size);
      free (data->cntx_name);
      free (data->acls_a_ptr);
      free (data->acls_d_ptr);
      free (data);
    }
}


static bool
is_directory_link (const char *file_name)
{
  struct stat st;
  int e = errno;
  int res;
  
  res = (fstatat (chdir_fd, file_name, &st, AT_SYMLINK_NOFOLLOW) == 0 &&
	 S_ISLNK (st.st_mode) &&
	 fstatat (chdir_fd, file_name, &st, 0) == 0 &&
	 S_ISDIR (st.st_mode));
  errno = e;
  return res;
}

/* Extractor functions for various member types */

static int
extract_dir (char *file_name, int typeflag)
{
  int status;
  mode_t mode;
  mode_t current_mode = 0;
  mode_t current_mode_mask = 0;
  int atflag = 0;
  bool interdir_made = false;

  /* Save 'root device' to avoid purging mount points. */
  if (one_file_system_option && root_device == 0)
    {
      struct stat st;

      if (fstatat (chdir_fd, ".", &st, 0) != 0)
	stat_diag (".");
      else
	root_device = st.st_dev;
    }

  if (incremental_option)
    /* Read the entry and delete files that aren't listed in the archive.  */
    purge_directory (file_name);
  else if (typeflag == GNUTYPE_DUMPDIR)
    skip_member ();

  /* If ownership or permissions will be restored later, create the
     directory with restrictive permissions at first, so that in the
     meantime processes owned by other users do not inadvertently
     create files under this directory that inherit the wrong owner,
     group, or permissions from the directory.  If not root, though,
     make the directory writeable and searchable at first, so that
     files can be created under it.  */
  mode = ((current_stat_info.stat.st_mode
	   & (0 < same_owner_option || 0 < same_permissions_option
	      ? S_IRWXU
	      : MODE_RWX))
	  | (we_are_root ? 0 : MODE_WXUSR));

  for (;;)
    {
      status = mkdirat (chdir_fd, file_name, mode);
      if (status == 0)
	{
	  current_mode = mode & ~ current_umask;
	  current_mode_mask = MODE_RWX;
	  atflag = AT_SYMLINK_NOFOLLOW;
	  break;
	}

      if (errno == EEXIST
	  && (interdir_made
	      || keep_directory_symlink_option
	      || old_files_option == DEFAULT_OLD_FILES
	      || old_files_option == OVERWRITE_OLD_FILES))
	{
	  struct stat st;

	  if (keep_directory_symlink_option && is_directory_link (file_name))
	    return 0;
	  
	  if (deref_stat (file_name, &st) == 0)
	    {
	      current_mode = st.st_mode;
	      current_mode_mask = ALL_MODE_BITS;

	      if (S_ISDIR (current_mode))
		{
		  if (interdir_made)
		    {
		      repair_delayed_set_stat (file_name, &st);
		      return 0;
		    }
		  break;
		}
	    }
	  errno = EEXIST;
	}

      switch (maybe_recoverable (file_name, false, &interdir_made))
	{
	case RECOVER_OK:
	  continue;

	case RECOVER_SKIP:
	  break;

	case RECOVER_NO:
	  if (errno != EEXIST)
	    {
	      mkdir_error (file_name);
	      return 1;
	    }
	  break;
	}
      break;
    }

  if (status == 0
      || old_files_option == DEFAULT_OLD_FILES
      || old_files_option == OVERWRITE_OLD_FILES)
    delay_set_stat (file_name, &current_stat_info,
		    current_mode, current_mode_mask,
		    current_stat_info.stat.st_mode, atflag);
  return status;
}



static int
open_output_file (char const *file_name, int typeflag, mode_t mode,
                  int file_created, mode_t *current_mode,
                  mode_t *current_mode_mask)
{
  int fd;
  bool overwriting_old_files = old_files_option == OVERWRITE_OLD_FILES;
  int openflag = (O_WRONLY | O_BINARY | O_CLOEXEC | O_NOCTTY | O_NONBLOCK
		  | O_CREAT
		  | (overwriting_old_files
		     ? O_TRUNC | (dereference_option ? 0 : O_NOFOLLOW)
		     : O_EXCL));

  /* File might be created in set_xattr. So clear O_EXCL to avoid open() fail */
  if (file_created)
    openflag = openflag & ~O_EXCL;

  if (typeflag == CONTTYPE)
    {
      static int conttype_diagnosed;

      if (!conttype_diagnosed)
	{
	  conttype_diagnosed = 1;
	  WARNOPT (WARN_CONTIGUOUS_CAST,
		   (0, 0, _("Extracting contiguous files as regular files")));
	}
    }

  /* If O_NOFOLLOW is needed but does not work, check for a symlink
     separately.  There's a race condition, but that cannot be avoided
     on hosts lacking O_NOFOLLOW.  */
  if (! HAVE_WORKING_O_NOFOLLOW
      && overwriting_old_files && ! dereference_option)
    {
      struct stat st;
      if (fstatat (chdir_fd, file_name, &st, AT_SYMLINK_NOFOLLOW) == 0
	  && S_ISLNK (st.st_mode))
	{
	  errno = ELOOP;
	  return -1;
	}
    }

  fd = openat (chdir_fd, file_name, openflag, mode);
  if (0 <= fd)
    {
      if (overwriting_old_files)
	{
	  struct stat st;
	  if (fstat (fd, &st) != 0)
	    {
	      int e = errno;
	      close (fd);
	      errno = e;
	      return -1;
	    }
	  if (! S_ISREG (st.st_mode))
	    {
	      close (fd);
	      errno = EEXIST;
	      return -1;
	    }
	  *current_mode = st.st_mode;
	  *current_mode_mask = ALL_MODE_BITS;
	}
      else
	{
	  *current_mode = mode & ~ current_umask;
	  *current_mode_mask = MODE_RWX;
	}
    }

  return fd;
}

static int
extract_file (char *file_name, int typeflag)
{
  int fd;
  off_t size;
  union block *data_block;
  int status;
  size_t count;
  size_t written;
  bool interdir_made = false;
  mode_t mode = (current_stat_info.stat.st_mode & MODE_RWX
		 & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0));
  mode_t invert_permissions = 0 < same_owner_option ? mode & (S_IRWXG | S_IRWXO)
                                                    : 0;
  mode_t current_mode = 0;
  mode_t current_mode_mask = 0;

  if (to_stdout_option)
    fd = STDOUT_FILENO;
  else if (to_command_option)
    {
      fd = sys_exec_command (file_name, 'f', &current_stat_info);
      if (fd < 0)
	{
	  skip_member ();
	  return 0;
	}
    }
  else
    {
      int file_created = 0;
      if (set_xattr (file_name, &current_stat_info, invert_permissions,
                     typeflag, &file_created))
        {
          skip_member ();
          open_error (file_name);
          return 1;
        }

      while ((fd = open_output_file (file_name, typeflag, mode,
                                     file_created, &current_mode,
                                     &current_mode_mask))
	     < 0)
	{
	  int recover = maybe_recoverable (file_name, true, &interdir_made);
	  if (recover != RECOVER_OK)
	    {
	      skip_member ();
	      if (recover == RECOVER_SKIP)
		return 0;
	      open_error (file_name);
	      return 1;
	    }
	}
    }

  mv_begin_read (&current_stat_info);
  if (current_stat_info.is_sparse)
    sparse_extract_file (fd, &current_stat_info, &size);
  else
    for (size = current_stat_info.stat.st_size; size > 0; )
      {
	mv_size_left (size);

	/* Locate data, determine max length writeable, write it,
	   block that we have used the data, then check if the write
	   worked.  */

	data_block = find_next_block ();
	if (! data_block)
	  {
	    ERROR ((0, 0, _("Unexpected EOF in archive")));
	    break;		/* FIXME: What happens, then?  */
	  }

	written = available_space_after (data_block);

	if (written > size)
	  written = size;
	errno = 0;
	count = blocking_write (fd, data_block->buffer, written);
	size -= written;

	set_next_block_after ((union block *)
			      (data_block->buffer + written - 1));
	if (count != written)
	  {
	    if (!to_command_option)
	      write_error_details (file_name, count, written);
	    /* FIXME: shouldn't we restore from backup? */
	    break;
	  }
      }

  skip_file (size);

  mv_end ();

  /* If writing to stdout, don't try to do anything to the filename;
     it doesn't exist, or we don't want to touch it anyway.  */

  if (to_stdout_option)
    return 0;

  if (! to_command_option)
    set_stat (file_name, &current_stat_info, fd,
	      current_mode, current_mode_mask, typeflag, false,
	      (old_files_option == OVERWRITE_OLD_FILES
	       ? 0 : AT_SYMLINK_NOFOLLOW));

  status = close (fd);
  if (status < 0)
    close_error (file_name);

  if (to_command_option)
    sys_wait_command ();

  return status;
}

/* Create a placeholder file with name FILE_NAME, which will be
   replaced after other extraction is done by a symbolic link if
   IS_SYMLINK is true, and by a hard link otherwise.  Set
   *INTERDIR_MADE if an intermediate directory is made in the
   process.  */

static int
create_placeholder_file (char *file_name, bool is_symlink, bool *interdir_made)
{
  int fd;
  struct stat st;

  while ((fd = openat (chdir_fd, file_name, O_WRONLY | O_CREAT | O_EXCL, 0)) < 0)
    {
      switch (maybe_recoverable (file_name, false, interdir_made))
	{
	case RECOVER_OK:
	  continue;

	case RECOVER_SKIP:
	  return 0;

	case RECOVER_NO:
	  open_error (file_name);
	  return -1;
	}
      }

  if (fstat (fd, &st) != 0)
    {
      stat_error (file_name);
      close (fd);
    }
  else if (close (fd) != 0)
    close_error (file_name);
  else
    {
      struct delayed_set_stat *h;
      struct delayed_link *p =
	xmalloc (offsetof (struct delayed_link, target)
		 + strlen (current_stat_info.link_name)
		 + 1);
      p->next = delayed_link_head;
      delayed_link_head = p;
      p->dev = st.st_dev;
      p->ino = st.st_ino;
      p->birthtime = get_stat_birthtime (&st);
      p->is_symlink = is_symlink;
      if (is_symlink)
	{
	  p->mode = current_stat_info.stat.st_mode;
	  p->uid = current_stat_info.stat.st_uid;
	  p->gid = current_stat_info.stat.st_gid;
	  p->atime = current_stat_info.atime;
	  p->mtime = current_stat_info.mtime;
	}
      p->change_dir = chdir_current;
      p->sources = xmalloc (offsetof (struct string_list, string)
			    + strlen (file_name) + 1);
      p->sources->next = 0;
      strcpy (p->sources->string, file_name);
      p->cntx_name = NULL;
      assign_string (&p->cntx_name, current_stat_info.cntx_name);
      p->acls_a_ptr = NULL;
      p->acls_a_len = 0;
      p->acls_d_ptr = NULL;
      p->acls_d_len = 0;
      xheader_xattr_copy (&current_stat_info, &p->xattr_map, &p->xattr_map_size);
      strcpy (p->target, current_stat_info.link_name);

      h = delayed_set_stat_head;
      if (h && ! h->after_links
	  && strncmp (file_name, h->file_name, h->file_name_len) == 0
	  && ISSLASH (file_name[h->file_name_len])
	  && (last_component (file_name) == file_name + h->file_name_len + 1))
	mark_after_links (h);

      return 0;
    }

  return -1;
}

static int
extract_link (char *file_name, int typeflag)
{
  bool interdir_made = false;
  char const *link_name;
  int rc;

  link_name = current_stat_info.link_name;

  if (! absolute_names_option && contains_dot_dot (link_name))
    return create_placeholder_file (file_name, false, &interdir_made);

  do
    {
      struct stat st1, st2;
      int e;
      int status = linkat (chdir_fd, link_name, chdir_fd, file_name, 0);
      e = errno;

      if (status == 0)
	{
	  struct delayed_link *ds = delayed_link_head;
	  if (ds
	      && fstatat (chdir_fd, link_name, &st1, AT_SYMLINK_NOFOLLOW) == 0)
	    for (; ds; ds = ds->next)
	      if (ds->change_dir == chdir_current
		  && ds->dev == st1.st_dev
		  && ds->ino == st1.st_ino
		  && (timespec_cmp (ds->birthtime, get_stat_birthtime (&st1))
		      == 0))
		{
		  struct string_list *p =  xmalloc (offsetof (struct string_list, string)
						    + strlen (file_name) + 1);
		  strcpy (p->string, file_name);
		  p->next = ds->sources;
		  ds->sources = p;
		  break;
		}
	  return 0;
	}
      else if ((e == EEXIST && strcmp (link_name, file_name) == 0)
	       || ((fstatat (chdir_fd, link_name, &st1, AT_SYMLINK_NOFOLLOW)
		    == 0)
		   && (fstatat (chdir_fd, file_name, &st2, AT_SYMLINK_NOFOLLOW)
		       == 0)
		   && st1.st_dev == st2.st_dev
		   && st1.st_ino == st2.st_ino))
	return 0;

      errno = e;
    }
  while ((rc = maybe_recoverable (file_name, false, &interdir_made))
	 == RECOVER_OK);

  if (rc == RECOVER_SKIP)
    return 0;
  if (!(incremental_option && errno == EEXIST))
    {
      link_error (link_name, file_name);
      return 1;
    }
  return 0;
}

static int
extract_symlink (char *file_name, int typeflag)
{
#ifdef HAVE_SYMLINK
  bool interdir_made = false;

  if (! absolute_names_option
      && (IS_ABSOLUTE_FILE_NAME (current_stat_info.link_name)
	  || contains_dot_dot (current_stat_info.link_name)))
    return create_placeholder_file (file_name, true, &interdir_made);

  while (symlinkat (current_stat_info.link_name, chdir_fd, file_name) != 0)
    switch (maybe_recoverable (file_name, false, &interdir_made))
      {
      case RECOVER_OK:
	continue;

      case RECOVER_SKIP:
	return 0;

      case RECOVER_NO:
	symlink_error (current_stat_info.link_name, file_name);
	return -1;
      }

  set_stat (file_name, &current_stat_info, -1, 0, 0,
	    SYMTYPE, false, AT_SYMLINK_NOFOLLOW);
  return 0;

#else
  static int warned_once;

  if (!warned_once)
    {
      warned_once = 1;
      WARNOPT (WARN_SYMLINK_CAST,
	       (0, 0,
		_("Attempting extraction of symbolic links as hard links")));
    }
  return extract_link (file_name, typeflag);
#endif
}

#if S_IFCHR || S_IFBLK
static int
extract_node (char *file_name, int typeflag)
{
  bool interdir_made = false;
  mode_t mode = (current_stat_info.stat.st_mode & (MODE_RWX | S_IFBLK | S_IFCHR)
		 & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0));

  while (mknodat (chdir_fd, file_name, mode, current_stat_info.stat.st_rdev)
	 != 0)
    switch (maybe_recoverable (file_name, false, &interdir_made))
      {
      case RECOVER_OK:
	continue;

      case RECOVER_SKIP:
	return 0;

      case RECOVER_NO:
	mknod_error (file_name);
	return -1;
      }

  set_stat (file_name, &current_stat_info, -1,
	    mode & ~ current_umask, MODE_RWX,
	    typeflag, false, AT_SYMLINK_NOFOLLOW);
  return 0;
}
#endif

#if HAVE_MKFIFO || defined mkfifo
static int
extract_fifo (char *file_name, int typeflag)
{
  bool interdir_made = false;
  mode_t mode = (current_stat_info.stat.st_mode & MODE_RWX
		 & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0));

  while (mkfifoat (chdir_fd, file_name, mode) != 0)
    switch (maybe_recoverable (file_name, false, &interdir_made))
      {
      case RECOVER_OK:
	continue;

      case RECOVER_SKIP:
	return 0;

      case RECOVER_NO:
	mkfifo_error (file_name);
	return -1;
      }

  set_stat (file_name, &current_stat_info, -1,
	    mode & ~ current_umask, MODE_RWX,
	    typeflag, false, AT_SYMLINK_NOFOLLOW);
  return 0;
}
#endif

static int
extract_volhdr (char *file_name, int typeflag)
{
  skip_member ();
  return 0;
}

static int
extract_failure (char *file_name, int typeflag)
{
  return 1;
}

static int
extract_skip (char *file_name, int typeflag)
{
  skip_member ();
  return 0;
}

typedef int (*tar_extractor_t) (char *file_name, int typeflag);



/* Prepare to extract a file. Find extractor function.
   Return zero if extraction should not proceed.  */

static int
prepare_to_extract (char const *file_name, int typeflag, tar_extractor_t *fun)
{
  int rc = 1;

  if (EXTRACT_OVER_PIPE)
    rc = 0;

  /* Select the extractor */
  switch (typeflag)
    {
    case GNUTYPE_SPARSE:
      *fun = extract_file;
      rc = 1;
      break;

    case AREGTYPE:
    case REGTYPE:
    case CONTTYPE:
      /* Appears to be a file.  But BSD tar uses the convention that a slash
	 suffix means a directory.  */
      if (current_stat_info.had_trailing_slash)
	*fun = extract_dir;
      else
	{
	  *fun = extract_file;
	  rc = 1;
	}
      break;

    case SYMTYPE:
      *fun = extract_symlink;
      break;

    case LNKTYPE:
      *fun = extract_link;
      break;

#if S_IFCHR
    case CHRTYPE:
      current_stat_info.stat.st_mode |= S_IFCHR;
      *fun = extract_node;
      break;
#endif

#if S_IFBLK
    case BLKTYPE:
      current_stat_info.stat.st_mode |= S_IFBLK;
      *fun = extract_node;
      break;
#endif

#if HAVE_MKFIFO || defined mkfifo
    case FIFOTYPE:
      *fun = extract_fifo;
      break;
#endif

    case DIRTYPE:
    case GNUTYPE_DUMPDIR:
      *fun = extract_dir;
      if (current_stat_info.is_dumpdir)
	delay_directory_restore_option = true;
      break;

    case GNUTYPE_VOLHDR:
      *fun = extract_volhdr;
      break;

    case GNUTYPE_MULTIVOL:
      ERROR ((0, 0,
	      _("%s: Cannot extract -- file is continued from another volume"),
	      quotearg_colon (current_stat_info.file_name)));
      *fun = extract_skip;
      break;

    case GNUTYPE_LONGNAME:
    case GNUTYPE_LONGLINK:
      ERROR ((0, 0, _("Unexpected long name header")));
      *fun = extract_failure;
      break;

    default:
      WARNOPT (WARN_UNKNOWN_CAST,
	       (0, 0,
		_("%s: Unknown file type '%c', extracted as normal file"),
		quotearg_colon (file_name), typeflag));
      *fun = extract_file;
    }

  /* Determine whether the extraction should proceed */
  if (rc == 0)
    return 0;

  switch (old_files_option)
    {
    case UNLINK_FIRST_OLD_FILES:
      if (!remove_any_file (file_name,
                            recursive_unlink_option ? RECURSIVE_REMOVE_OPTION
                                                      : ORDINARY_REMOVE_OPTION)
	  && errno && errno != ENOENT)
	{
	  unlink_error (file_name);
	  return 0;
	}
      break;

    case KEEP_NEWER_FILES:
      if (file_newer_p (file_name, 0, &current_stat_info))
	{
	  WARNOPT (WARN_IGNORE_NEWER,
		   (0, 0, _("Current %s is newer or same age"),
		    quote (file_name)));
	  return 0;
	}
      break;

    default:
      break;
    }

  return 1;
}

/* Extract a file from the archive.  */
void
extract_archive (void)
{
  char typeflag;
  tar_extractor_t fun;
  bool skip_dotdot_name;

  fatal_exit_hook = extract_finish;

  set_next_block_after (current_header);

  skip_dotdot_name = (!absolute_names_option
		      && contains_dot_dot (current_stat_info.orig_file_name));
  if (skip_dotdot_name)
    ERROR ((0, 0, _("%s: Member name contains '..'"),
	    quotearg_colon (current_stat_info.orig_file_name)));

  if (!current_stat_info.file_name[0]
      || skip_dotdot_name
      || (interactive_option
	  && !confirm ("extract", current_stat_info.file_name)))
    {
      skip_member ();
      return;
    }

  /* Print the block from current_header and current_stat.  */
  if (verbose_option)
    print_header (&current_stat_info, current_header, -1);

  /* Restore stats for all non-ancestor directories, unless
     it is an incremental archive.
     (see NOTICE in the comment to delay_set_stat above) */
  if (!delay_directory_restore_option)
    {
      int dir = chdir_current;
      apply_nonancestor_delayed_set_stat (current_stat_info.file_name, 0);
      chdir_do (dir);
    }

  /* Take a safety backup of a previously existing file.  */

  if (backup_option)
    if (!maybe_backup_file (current_stat_info.file_name, 0))
      {
	int e = errno;
	ERROR ((0, e, _("%s: Was unable to backup this file"),
		quotearg_colon (current_stat_info.file_name)));
	skip_member ();
	return;
      }

  /* Extract the archive entry according to its type.  */
  /* KLUDGE */
  typeflag = sparse_member_p (&current_stat_info) ?
                  GNUTYPE_SPARSE : current_header->header.typeflag;

  if (prepare_to_extract (current_stat_info.file_name, typeflag, &fun))
    {
      if (fun && (*fun) (current_stat_info.file_name, typeflag)
	  && backup_option)
	undo_last_backup ();
    }
  else
    skip_member ();

}

/* Extract the links whose final extraction were delayed.  */
static void
apply_delayed_links (void)
{
  struct delayed_link *ds;

  for (ds = delayed_link_head; ds; )
    {
      struct string_list *sources = ds->sources;
      char const *valid_source = 0;

      chdir_do (ds->change_dir);

      for (sources = ds->sources; sources; sources = sources->next)
	{
	  char const *source = sources->string;
	  struct stat st;

	  /* Make sure the placeholder file is still there.  If not,
	     don't create a link, as the placeholder was probably
	     removed by a later extraction.  */
	  if (fstatat (chdir_fd, source, &st, AT_SYMLINK_NOFOLLOW) == 0
	      && st.st_dev == ds->dev
	      && st.st_ino == ds->ino
	      && timespec_cmp (get_stat_birthtime (&st), ds->birthtime) == 0)
	    {
	      /* Unlink the placeholder, then create a hard link if possible,
		 a symbolic link otherwise.  */
	      if (unlinkat (chdir_fd, source, 0) != 0)
		unlink_error (source);
	      else if (valid_source
		       && (linkat (chdir_fd, valid_source, chdir_fd, source, 0)
			   == 0))
		;
	      else if (!ds->is_symlink)
		{
		  if (linkat (chdir_fd, ds->target, chdir_fd, source, 0) != 0)
		    link_error (ds->target, source);
		}
	      else if (symlinkat (ds->target, chdir_fd, source) != 0)
		symlink_error (ds->target, source);
	      else
		{
		  struct tar_stat_info st1;
		  st1.stat.st_mode = ds->mode;
		  st1.stat.st_uid = ds->uid;
		  st1.stat.st_gid = ds->gid;
		  st1.atime = ds->atime;
		  st1.mtime = ds->mtime;
                  st1.cntx_name = ds->cntx_name;
                  st1.acls_a_ptr = ds->acls_a_ptr;
                  st1.acls_a_len = ds->acls_a_len;
                  st1.acls_d_ptr = ds->acls_d_ptr;
                  st1.acls_d_len = ds->acls_d_len;
                  st1.xattr_map = ds->xattr_map;
                  st1.xattr_map_size = ds->xattr_map_size;
		  set_stat (source, &st1, -1, 0, 0, SYMTYPE,
			    false, AT_SYMLINK_NOFOLLOW);
		  valid_source = source;
		}
	    }
	}

      for (sources = ds->sources; sources; )
	{
	  struct string_list *next = sources->next;
	  free (sources);
	  sources = next;
	}

   xheader_xattr_free (ds->xattr_map, ds->xattr_map_size);
   free (ds->cntx_name);

      {
	struct delayed_link *next = ds->next;
	free (ds);
	ds = next;
      }
    }

  delayed_link_head = 0;
}

/* Finish the extraction of an archive.  */
void
extract_finish (void)
{
  /* First, fix the status of ordinary directories that need fixing.  */
  apply_nonancestor_delayed_set_stat ("", 0);

  /* Then, apply delayed links, so that they don't affect delayed
     directory status-setting for ordinary directories.  */
  apply_delayed_links ();

  /* Finally, fix the status of directories that are ancestors
     of delayed links.  */
  apply_nonancestor_delayed_set_stat ("", 1);
}

bool
rename_directory (char *src, char *dst)
{
  if (renameat (chdir_fd, src, chdir_fd, dst) != 0)
    {
      int e = errno;
      bool interdir_made;

      switch (e)
	{
	case ENOENT:
	  if (make_directories (dst, &interdir_made) == 0)
	    {
	      if (renameat (chdir_fd, src, chdir_fd, dst) == 0)
		return true;
	      e = errno;
	    }
	  break;

	case EXDEV:
	  /* FIXME: Fall back to recursive copying */

	default:
	  break;
	}

      ERROR ((0, e, _("Cannot rename %s to %s"),
	      quote_n (0, src),
	      quote_n (1, dst)));
      return false;
    }
  return true;
}