aboutsummaryrefslogtreecommitdiff
path: root/util-linux/mount.c
blob: 6e63a01fc2ac06477bfcd07072373143752e3982 (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
/* vi: set sw=4 ts=4: */
/*
 * Mini mount implementation for busybox
 *
 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 * Copyright (C) 2005-2006 by Rob Landley <rob@landley.net>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* Design notes: There is no spec for mount.  Remind me to write one.

   mount_main() calls singlemount() which calls mount_it_now().

   mount_main() can loop through /etc/fstab for mount -a
   singlemount() can loop through /etc/filesystems for fstype detection.
   mount_it_now() does the actual mount.
*/

#include <mntent.h>
#include <syslog.h>
#include "libbb.h"

/* For FEATURE_MOUNT_LABEL only */
#include "volume_id.h"

/* Needed for nfs support only */
#include <sys/utsname.h>
#undef TRUE
#undef FALSE
#include <rpc/rpc.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_clnt.h>

#ifndef MS_SILENT
#define MS_SILENT	(1 << 15)
#endif
/* Grab more as needed from util-linux's mount/mount_constants.h */
#ifndef MS_DIRSYNC
#define MS_DIRSYNC      128     /* Directory modifications are synchronous */
#endif


#if defined(__dietlibc__)
/* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
 * dietlibc-0.30 does not have implementation of getmntent_r() */
static struct mntent *getmntent_r(FILE* stream, struct mntent* result, char* buffer, int bufsize)
{
	struct mntent* ment = getmntent(stream);
	memcpy(result, ment, sizeof(struct mntent));
	return result;
}
#endif


// Not real flags, but we want to be able to check for this.
enum {
	MOUNT_USERS  = (1 << 28) * ENABLE_DESKTOP,
	MOUNT_NOAUTO = (1 << 29),
	MOUNT_SWAP   = (1 << 30),
};


#define OPTION_STR "o:t:rwanfvsi"
enum {
	OPT_o = (1 << 0),
	OPT_t = (1 << 1),
	OPT_r = (1 << 2),
	OPT_w = (1 << 3),
	OPT_a = (1 << 4),
	OPT_n = (1 << 5),
	OPT_f = (1 << 6),
	OPT_v = (1 << 7),
	OPT_s = (1 << 8),
	OPT_i = (1 << 9),
};

#if ENABLE_FEATURE_MTAB_SUPPORT
#define useMtab (!(option_mask32 & OPT_n))
#else
#define useMtab 0
#endif

#if ENABLE_FEATURE_MOUNT_FAKE
#define fakeIt (option_mask32 & OPT_f)
#else
#define fakeIt 0
#endif


// TODO: more "user" flag compatibility.
// "user" option (from mount manpage):
// Only the user that mounted a filesystem can unmount it again.
// If any user should be able to unmount, then use users instead of user
// in the fstab line.  The owner option is similar to the user option,
// with the restriction that the user must be the owner of the special file.
// This may be useful e.g. for /dev/fd if a login script makes
// the console user owner of this device.

/* Standard mount options (from -o options or --options), with corresponding
 * flags */

static const int32_t mount_options[] = {
	// MS_FLAGS set a bit.  ~MS_FLAGS disable that bit.  0 flags are NOPs.

	USE_FEATURE_MOUNT_LOOP(
		/* "loop" */ 0,
	)

	USE_FEATURE_MOUNT_FSTAB(
		/* "defaults" */ 0,
		/* "quiet" 0 - do not filter out, vfat wants to see it */
		/* "noauto" */ MOUNT_NOAUTO,
		/* "sw"     */ MOUNT_SWAP,
		/* "swap"   */ MOUNT_SWAP,
		USE_DESKTOP(/* "user"  */ MOUNT_USERS,)
		USE_DESKTOP(/* "users" */ MOUNT_USERS,)
		/* "_netdev" */ 0,
	)

	USE_FEATURE_MOUNT_FLAGS(
		// vfs flags
		/* "nosuid"      */ MS_NOSUID,
		/* "suid"        */ ~MS_NOSUID,
		/* "dev"         */ ~MS_NODEV,
		/* "nodev"       */ MS_NODEV,
		/* "exec"        */ ~MS_NOEXEC,
		/* "noexec"      */ MS_NOEXEC,
		/* "sync"        */ MS_SYNCHRONOUS,
		/* "dirsync"     */ MS_DIRSYNC,
		/* "async"       */ ~MS_SYNCHRONOUS,
		/* "atime"       */ ~MS_NOATIME,
		/* "noatime"     */ MS_NOATIME,
		/* "diratime"    */ ~MS_NODIRATIME,
		/* "nodiratime"  */ MS_NODIRATIME,
		/* "loud"        */ ~MS_SILENT,

		// action flags
		/* "bind"        */ MS_BIND,
		/* "move"        */ MS_MOVE,
		/* "shared"      */ MS_SHARED,
		/* "slave"       */ MS_SLAVE,
		/* "private"     */ MS_PRIVATE,
		/* "unbindable"  */ MS_UNBINDABLE,
		/* "rshared"     */ MS_SHARED|MS_RECURSIVE,
		/* "rslave"      */ MS_SLAVE|MS_RECURSIVE,
		/* "rprivate"    */ MS_SLAVE|MS_RECURSIVE,
		/* "runbindable" */ MS_UNBINDABLE|MS_RECURSIVE,
	)

	// Always understood.
	/* "ro"      */ MS_RDONLY,  // vfs flag
	/* "rw"      */ ~MS_RDONLY, // vfs flag
	/* "remount" */ MS_REMOUNT  // action flag
};

static const char mount_option_str[] =
	USE_FEATURE_MOUNT_LOOP(
		"loop" "\0"
	)
	USE_FEATURE_MOUNT_FSTAB(
		"defaults" "\0"
		/* "quiet" "\0" - do not filter out, vfat wants to see it */
		"noauto" "\0"
		"sw" "\0"
		"swap" "\0"
		USE_DESKTOP("user" "\0")
		USE_DESKTOP("users" "\0")
		"_netdev" "\0"
	)
	USE_FEATURE_MOUNT_FLAGS(
		// vfs flags
		"nosuid" "\0"
		"suid" "\0"
		"dev" "\0"
		"nodev" "\0"
		"exec" "\0"
		"noexec" "\0"
		"sync" "\0"
		"dirsync" "\0"
		"async" "\0"
		"atime" "\0"
		"noatime" "\0"
		"diratime" "\0"
		"nodiratime" "\0"
		"loud" "\0"

		// action flags
		"bind" "\0"
		"move" "\0"
		"shared" "\0"
		"slave" "\0"
		"private" "\0"
		"unbindable" "\0"
		"rshared" "\0"
		"rslave" "\0"
		"rprivate" "\0"
		"runbindable" "\0"
	)

	// Always understood.
	"ro" "\0"        // vfs flag
	"rw" "\0"        // vfs flag
	"remount" "\0"   // action flag
;


struct globals {
#if ENABLE_FEATURE_MOUNT_NFS
	smalluint nfs_mount_version;
#endif
#if ENABLE_FEATURE_MOUNT_VERBOSE
	unsigned verbose;
#endif
	llist_t *fslist;
	char getmntent_buf[sizeof(bb_common_bufsiz1) - 8*3];

};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define nfs_mount_version (G.nfs_mount_version)
#if ENABLE_FEATURE_MOUNT_VERBOSE
#define verbose           (G.verbose          )
#else
#define verbose           0
#endif
#define fslist            (G.fslist           )
#define getmntent_buf     (G.getmntent_buf    )


#if ENABLE_FEATURE_MOUNT_VERBOSE
static int verbose_mount(const char *source, const char *target,
		const char *filesystemtype,
		unsigned long mountflags, const void *data)
{
	int rc;

	errno = 0;
	rc = mount(source, target, filesystemtype, mountflags, data);
	if (verbose >= 2)
		bb_perror_msg("mount('%s','%s','%s',0x%08lx,'%s'):%d",
			source, target, filesystemtype,
			mountflags, (char*)data, rc);
	return rc;
}
#else
#define verbose_mount(...) mount(__VA_ARGS__)
#endif

static int resolve_mount_spec(char **fsname)
{
	char *tmp = NULL;

	if (!strncmp(*fsname, "UUID=", 5))
		tmp = get_devname_from_uuid(*fsname + 5);
	else if (!strncmp(*fsname, "LABEL=", 6))
		tmp = get_devname_from_label(*fsname + 6);

	if (tmp) {
		*fsname = tmp;
		return 1;
	}
	return 0;
}

/* Append mount options to string */
static void append_mount_options(char **oldopts, const char *newopts)
{
	if (*oldopts && **oldopts) {
		/* do not insert options which are already there */
		while (newopts[0]) {
			char *p;
			int len = strlen(newopts);
			p = strchr(newopts, ',');
			if (p) len = p - newopts;
			p = *oldopts;
			while (1) {
				if (!strncmp(p, newopts, len)
				 && (p[len] == ',' || p[len] == '\0'))
					goto skip;
				p = strchr(p,',');
				if (!p) break;
				p++;
			}
			p = xasprintf("%s,%.*s", *oldopts, len, newopts);
			free(*oldopts);
			*oldopts = p;
 skip:
			newopts += len;
			while (newopts[0] == ',') newopts++;
		}
	} else {
		if (ENABLE_FEATURE_CLEAN_UP) free(*oldopts);
		*oldopts = xstrdup(newopts);
	}
}

/* Use the mount_options list to parse options into flags.
 * Also return list of unrecognized options if unrecognized!=NULL */
static long parse_mount_options(char *options, char **unrecognized)
{
	long flags = MS_SILENT;

	// Loop through options
	for (;;) {
		int i;
		char *comma = strchr(options, ',');
		const char *option_str = mount_option_str;

		if (comma) *comma = '\0';

		// Find this option in mount_options
		for (i = 0; i < ARRAY_SIZE(mount_options); i++) {
			if (!strcasecmp(option_str, options)) {
				long fl = mount_options[i];
				if (fl < 0) flags &= fl;
				else flags |= fl;
				break;
			}
			option_str += strlen(option_str) + 1;
		}
		// If unrecognized not NULL, append unrecognized mount options */
		if (unrecognized && i == ARRAY_SIZE(mount_options)) {
			// Add it to strflags, to pass on to kernel
			i = *unrecognized ? strlen(*unrecognized) : 0;
			*unrecognized = xrealloc(*unrecognized, i+strlen(options)+2);

			// Comma separated if it's not the first one
			if (i) (*unrecognized)[i++] = ',';
			strcpy((*unrecognized)+i, options);
		}

		if (!comma)
			break;
		// Advance to next option
		*comma = ',';
		options = ++comma;
	}

	return flags;
}

// Return a list of all block device backed filesystems

static llist_t *get_block_backed_filesystems(void)
{
	static const char filesystems[2][sizeof("/proc/filesystems")] = {
		"/etc/filesystems",
		"/proc/filesystems",
	};
	char *fs, *buf;
	llist_t *list = 0;
	int i;
	FILE *f;

	for (i = 0; i < 2; i++) {
		f = fopen(filesystems[i], "r");
		if (!f) continue;

		while ((buf = xmalloc_getline(f)) != 0) {
			if (!strncmp(buf, "nodev", 5) && isspace(buf[5]))
				continue;
			fs = skip_whitespace(buf);
			if (*fs=='#' || *fs=='*' || !*fs) continue;

			llist_add_to_end(&list, xstrdup(fs));
			free(buf);
		}
		if (ENABLE_FEATURE_CLEAN_UP) fclose(f);
	}

	return list;
}

#if ENABLE_FEATURE_CLEAN_UP
static void delete_block_backed_filesystems(void)
{
	llist_free(fslist, free);
}
#else
void delete_block_backed_filesystems(void);
#endif

// Perform actual mount of specific filesystem at specific location.
// NB: mp->xxx fields may be trashed on exit
static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
{
	int rc = 0;

	if (fakeIt) {
		if (verbose >= 2)
			bb_error_msg("would do mount('%s','%s','%s',0x%08lx,'%s')",
				mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
				vfsflags, filteropts);
		goto mtab;
	}

	// Mount, with fallback to read-only if necessary.
	for (;;) {
		errno = 0;
		rc = verbose_mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
				vfsflags, filteropts);

		// If mount failed, try
		// helper program <mnt_type>
		if (ENABLE_FEATURE_MOUNT_HELPERS && rc) {
			char *args[6];
			int errno_save = errno;
			args[0] = xasprintf("mount.%s", mp->mnt_type);
			rc = 1;
			if (filteropts) {
				args[rc++] = (char *)"-o";
				args[rc++] = filteropts;
			}
			args[rc++] = mp->mnt_fsname;
			args[rc++] = mp->mnt_dir;
			args[rc] = NULL;
			rc = wait4pid(spawn(args));
			free(args[0]);
			if (!rc)
				break;
			errno = errno_save;
		}

		if (!rc || (vfsflags & MS_RDONLY) || (errno != EACCES && errno != EROFS))
			break;
		if (!(vfsflags & MS_SILENT))
			bb_error_msg("%s is write-protected, mounting read-only",
						mp->mnt_fsname);
		vfsflags |= MS_RDONLY;
	}

	// Abort entirely if permission denied.

	if (rc && errno == EPERM)
		bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);

	/* If the mount was successful, and we're maintaining an old-style
	 * mtab file by hand, add the new entry to it now. */
 mtab:
	if (useMtab && !rc && !(vfsflags & MS_REMOUNT)) {
		char *fsname;
		FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
		const char *option_str = mount_option_str;
		int i;

		if (!mountTable) {
			bb_error_msg("no %s", bb_path_mtab_file);
			goto ret;
		}

		// Add vfs string flags

		for (i = 0; mount_options[i] != MS_REMOUNT; i++) {
			if (mount_options[i] > 0 && (mount_options[i] & vfsflags))
				append_mount_options(&(mp->mnt_opts), option_str);
			option_str += strlen(option_str) + 1;
		}

		// Remove trailing / (if any) from directory we mounted on

		i = strlen(mp->mnt_dir) - 1;
		if (i > 0 && mp->mnt_dir[i] == '/') mp->mnt_dir[i] = '\0';

		// Convert to canonical pathnames as needed

		mp->mnt_dir = bb_simplify_path(mp->mnt_dir);
		fsname = 0;
		if (!mp->mnt_type || !*mp->mnt_type) { /* bind mount */
			mp->mnt_fsname = fsname = bb_simplify_path(mp->mnt_fsname);
			mp->mnt_type = (char*)"bind";
		}
		mp->mnt_freq = mp->mnt_passno = 0;

		// Write and close.

		addmntent(mountTable, mp);
		endmntent(mountTable);
		if (ENABLE_FEATURE_CLEAN_UP) {
			free(mp->mnt_dir);
			free(fsname);
		}
	}
 ret:
	return rc;
}

#if ENABLE_FEATURE_MOUNT_NFS

/*
 * Linux NFS mount
 * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
 *
 * Licensed under GPLv2, see file LICENSE in this tarball for details.
 *
 * Wed Feb  8 12:51:48 1995, biro@yggdrasil.com (Ross Biro): allow all port
 * numbers to be specified on the command line.
 *
 * Fri, 8 Mar 1996 18:01:39, Swen Thuemmler <swen@uni-paderborn.de>:
 * Omit the call to connect() for Linux version 1.3.11 or later.
 *
 * Wed Oct  1 23:55:28 1997: Dick Streefland <dick_streefland@tasking.com>
 * Implemented the "bg", "fg" and "retry" mount options for NFS.
 *
 * 1999-02-22 Arkadiusz Mi�kiewicz <misiek@misiek.eu.org>
 * - added Native Language Support
 *
 * Modified by Olaf Kirch and Trond Myklebust for new NFS code,
 * plus NFSv3 stuff.
 */

/* This is just a warning of a common mistake.  Possibly this should be a
 * uclibc faq entry rather than in busybox... */
#if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
#error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support."
#endif

#define MOUNTPORT 635
#define MNTPATHLEN 1024
#define MNTNAMLEN 255
#define FHSIZE 32
#define FHSIZE3 64

typedef char fhandle[FHSIZE];

typedef struct {
	unsigned int fhandle3_len;
	char *fhandle3_val;
} fhandle3;

enum mountstat3 {
	MNT_OK = 0,
	MNT3ERR_PERM = 1,
	MNT3ERR_NOENT = 2,
	MNT3ERR_IO = 5,
	MNT3ERR_ACCES = 13,
	MNT3ERR_NOTDIR = 20,
	MNT3ERR_INVAL = 22,
	MNT3ERR_NAMETOOLONG = 63,
	MNT3ERR_NOTSUPP = 10004,
	MNT3ERR_SERVERFAULT = 10006,
};
typedef enum mountstat3 mountstat3;

struct fhstatus {
	unsigned int fhs_status;
	union {
		fhandle fhs_fhandle;
	} fhstatus_u;
};
typedef struct fhstatus fhstatus;

struct mountres3_ok {
	fhandle3 fhandle;
	struct {
		unsigned int auth_flavours_len;
		char *auth_flavours_val;
	} auth_flavours;
};
typedef struct mountres3_ok mountres3_ok;

struct mountres3 {
	mountstat3 fhs_status;
	union {
		mountres3_ok mountinfo;
	} mountres3_u;
};
typedef struct mountres3 mountres3;

typedef char *dirpath;

typedef char *name;

typedef struct mountbody *mountlist;

struct mountbody {
	name ml_hostname;
	dirpath ml_directory;
	mountlist ml_next;
};
typedef struct mountbody mountbody;

typedef struct groupnode *groups;

struct groupnode {
	name gr_name;
	groups gr_next;
};
typedef struct groupnode groupnode;

typedef struct exportnode *exports;

struct exportnode {
	dirpath ex_dir;
	groups ex_groups;
	exports ex_next;
};
typedef struct exportnode exportnode;

struct ppathcnf {
	int pc_link_max;
	short pc_max_canon;
	short pc_max_input;
	short pc_name_max;
	short pc_path_max;
	short pc_pipe_buf;
	uint8_t pc_vdisable;
	char pc_xxx;
	short pc_mask[2];
};
typedef struct ppathcnf ppathcnf;

#define MOUNTPROG 100005
#define MOUNTVERS 1

#define MOUNTPROC_NULL 0
#define MOUNTPROC_MNT 1
#define MOUNTPROC_DUMP 2
#define MOUNTPROC_UMNT 3
#define MOUNTPROC_UMNTALL 4
#define MOUNTPROC_EXPORT 5
#define MOUNTPROC_EXPORTALL 6

#define MOUNTVERS_POSIX 2

#define MOUNTPROC_PATHCONF 7

#define MOUNT_V3 3

#define MOUNTPROC3_NULL 0
#define MOUNTPROC3_MNT 1
#define MOUNTPROC3_DUMP 2
#define MOUNTPROC3_UMNT 3
#define MOUNTPROC3_UMNTALL 4
#define MOUNTPROC3_EXPORT 5

enum {
#ifndef NFS_FHSIZE
	NFS_FHSIZE = 32,
#endif
#ifndef NFS_PORT
	NFS_PORT = 2049
#endif
};

/*
 * We want to be able to compile mount on old kernels in such a way
 * that the binary will work well on more recent kernels.
 * Thus, if necessary we teach nfsmount.c the structure of new fields
 * that will come later.
 *
 * Moreover, the new kernel includes conflict with glibc includes
 * so it is easiest to ignore the kernel altogether (at compile time).
 */

struct nfs2_fh {
	char                    data[32];
};
struct nfs3_fh {
	unsigned short          size;
	unsigned char           data[64];
};

struct nfs_mount_data {
	int		version;		/* 1 */
	int		fd;			/* 1 */
	struct nfs2_fh	old_root;		/* 1 */
	int		flags;			/* 1 */
	int		rsize;			/* 1 */
	int		wsize;			/* 1 */
	int		timeo;			/* 1 */
	int		retrans;		/* 1 */
	int		acregmin;		/* 1 */
	int		acregmax;		/* 1 */
	int		acdirmin;		/* 1 */
	int		acdirmax;		/* 1 */
	struct sockaddr_in addr;		/* 1 */
	char		hostname[256];		/* 1 */
	int		namlen;			/* 2 */
	unsigned int	bsize;			/* 3 */
	struct nfs3_fh	root;			/* 4 */
};

/* bits in the flags field */
enum {
	NFS_MOUNT_SOFT = 0x0001,	/* 1 */
	NFS_MOUNT_INTR = 0x0002,	/* 1 */
	NFS_MOUNT_SECURE = 0x0004,	/* 1 */
	NFS_MOUNT_POSIX = 0x0008,	/* 1 */
	NFS_MOUNT_NOCTO = 0x0010,	/* 1 */
	NFS_MOUNT_NOAC = 0x0020,	/* 1 */
	NFS_MOUNT_TCP = 0x0040,		/* 2 */
	NFS_MOUNT_VER3 = 0x0080,	/* 3 */
	NFS_MOUNT_KERBEROS = 0x0100,	/* 3 */
	NFS_MOUNT_NONLM = 0x0200	/* 3 */
};


/*
 * We need to translate between nfs status return values and
 * the local errno values which may not be the same.
 *
 * Andreas Schwab <schwab@LS5.informatik.uni-dortmund.de>: change errno:
 * "after #include <errno.h> the symbol errno is reserved for any use,
 *  it cannot even be used as a struct tag or field name".
 */

#ifndef EDQUOT
#define EDQUOT	ENOSPC
#endif

// Convert each NFSERR_BLAH into EBLAH

static const struct {
	short stat;
	short errnum;
} nfs_errtbl[] = {
	{0,0}, {1,EPERM}, {2,ENOENT}, {5,EIO}, {6,ENXIO}, {13,EACCES}, {17,EEXIST},
	{19,ENODEV}, {20,ENOTDIR}, {21,EISDIR}, {22,EINVAL}, {27,EFBIG},
	{28,ENOSPC}, {30,EROFS}, {63,ENAMETOOLONG}, {66,ENOTEMPTY}, {69,EDQUOT},
	{70,ESTALE}, {71,EREMOTE}, {-1,EIO}
};

static char *nfs_strerror(int status)
{
	int i;

	for (i = 0; nfs_errtbl[i].stat != -1; i++) {
		if (nfs_errtbl[i].stat == status)
			return strerror(nfs_errtbl[i].errnum);
	}
	return xasprintf("unknown nfs status return value: %d", status);
}

static bool_t xdr_fhandle(XDR *xdrs, fhandle objp)
{
	if (!xdr_opaque(xdrs, objp, FHSIZE))
		 return FALSE;
	return TRUE;
}

static bool_t xdr_fhstatus(XDR *xdrs, fhstatus *objp)
{
	if (!xdr_u_int(xdrs, &objp->fhs_status))
		 return FALSE;
	switch (objp->fhs_status) {
	case 0:
		if (!xdr_fhandle(xdrs, objp->fhstatus_u.fhs_fhandle))
			 return FALSE;
		break;
	default:
		break;
	}
	return TRUE;
}

static bool_t xdr_dirpath(XDR *xdrs, dirpath *objp)
{
	if (!xdr_string(xdrs, objp, MNTPATHLEN))
		 return FALSE;
	return TRUE;
}

static bool_t xdr_fhandle3(XDR *xdrs, fhandle3 *objp)
{
	if (!xdr_bytes(xdrs, (char **)&objp->fhandle3_val, (unsigned int *) &objp->fhandle3_len, FHSIZE3))
		 return FALSE;
	return TRUE;
}

static bool_t xdr_mountres3_ok(XDR *xdrs, mountres3_ok *objp)
{
	if (!xdr_fhandle3(xdrs, &objp->fhandle))
		return FALSE;
	if (!xdr_array(xdrs, &(objp->auth_flavours.auth_flavours_val), &(objp->auth_flavours.auth_flavours_len), ~0,
				sizeof (int), (xdrproc_t) xdr_int))
		return FALSE;
	return TRUE;
}

static bool_t xdr_mountstat3(XDR *xdrs, mountstat3 *objp)
{
	if (!xdr_enum(xdrs, (enum_t *) objp))
		 return FALSE;
	return TRUE;
}

static bool_t xdr_mountres3(XDR *xdrs, mountres3 *objp)
{
	if (!xdr_mountstat3(xdrs, &objp->fhs_status))
		return FALSE;
	switch (objp->fhs_status) {
	case MNT_OK:
		if (!xdr_mountres3_ok(xdrs, &objp->mountres3_u.mountinfo))
			 return FALSE;
		break;
	default:
		break;
	}
	return TRUE;
}

#define MAX_NFSPROT ((nfs_mount_version >= 4) ? 3 : 2)

/*
 * Unfortunately, the kernel prints annoying console messages
 * in case of an unexpected nfs mount version (instead of
 * just returning some error).  Therefore we'll have to try
 * and figure out what version the kernel expects.
 *
 * Variables:
 *	KERNEL_NFS_MOUNT_VERSION: kernel sources at compile time
 *	NFS_MOUNT_VERSION: these nfsmount sources at compile time
 *	nfs_mount_version: version this source and running kernel can handle
 */
static void
find_kernel_nfs_mount_version(void)
{
	int kernel_version;

	if (nfs_mount_version)
		return;

	nfs_mount_version = 4; /* default */

	kernel_version = get_linux_version_code();
	if (kernel_version) {
		if (kernel_version < KERNEL_VERSION(2,1,32))
			nfs_mount_version = 1;
		else if (kernel_version < KERNEL_VERSION(2,2,18) ||
				(kernel_version >= KERNEL_VERSION(2,3,0) &&
				 kernel_version < KERNEL_VERSION(2,3,99)))
			nfs_mount_version = 3;
		/* else v4 since 2.3.99pre4 */
	}
}

static void
get_mountport(struct pmap *pm_mnt,
	struct sockaddr_in *server_addr,
	long unsigned prog,
	long unsigned version,
	long unsigned proto,
	long unsigned port)
{
	struct pmaplist *pmap;

	server_addr->sin_port = PMAPPORT;
/* glibc 2.4 (still) has pmap_getmaps(struct sockaddr_in *).
 * I understand it like "IPv6 for this is not 100% ready" */
	pmap = pmap_getmaps(server_addr);

	if (version > MAX_NFSPROT)
		version = MAX_NFSPROT;
	if (!prog)
		prog = MOUNTPROG;
	pm_mnt->pm_prog = prog;
	pm_mnt->pm_vers = version;
	pm_mnt->pm_prot = proto;
	pm_mnt->pm_port = port;

	while (pmap) {
		if (pmap->pml_map.pm_prog != prog)
			goto next;
		if (!version && pm_mnt->pm_vers > pmap->pml_map.pm_vers)
			goto next;
		if (version > 2 && pmap->pml_map.pm_vers != version)
			goto next;
		if (version && version <= 2 && pmap->pml_map.pm_vers > 2)
			goto next;
		if (pmap->pml_map.pm_vers > MAX_NFSPROT ||
		    (proto && pm_mnt->pm_prot && pmap->pml_map.pm_prot != proto) ||
		    (port && pmap->pml_map.pm_port != port))
			goto next;
		memcpy(pm_mnt, &pmap->pml_map, sizeof(*pm_mnt));
 next:
		pmap = pmap->pml_next;
	}
	if (!pm_mnt->pm_vers)
		pm_mnt->pm_vers = MOUNTVERS;
	if (!pm_mnt->pm_port)
		pm_mnt->pm_port = MOUNTPORT;
	if (!pm_mnt->pm_prot)
		pm_mnt->pm_prot = IPPROTO_TCP;
}

#if BB_MMU
static int daemonize(void)
{
	int fd;
	int pid = fork();
	if (pid < 0) /* error */
		return -errno;
	if (pid > 0) /* parent */
		return 0;
	/* child */
	fd = xopen(bb_dev_null, O_RDWR);
	dup2(fd, 0);
	dup2(fd, 1);
	dup2(fd, 2);
	while (fd > 2) close(fd--);
	setsid();
	openlog(applet_name, LOG_PID, LOG_DAEMON);
	logmode = LOGMODE_SYSLOG;
	return 1;
}
#else
static inline int daemonize(void) { return -ENOSYS; }
#endif

// TODO
static inline int we_saw_this_host_before(const char *hostname ATTRIBUTE_UNUSED)
{
	return 0;
}

/* RPC strerror analogs are terminally idiotic:
 * *mandatory* prefix and \n at end.
 * This hopefully helps. Usage:
 * error_msg_rpc(clnt_*error*(" ")) */
static void error_msg_rpc(const char *msg)
{
	int len;
	while (msg[0] == ' ' || msg[0] == ':') msg++;
	len = strlen(msg);
	while (len && msg[len-1] == '\n') len--;
	bb_error_msg("%.*s", len, msg);
}

// NB: mp->xxx fields may be trashed on exit
static int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
{
	CLIENT *mclient;
	char *hostname;
	char *pathname;
	char *mounthost;
	struct nfs_mount_data data;
	char *opt;
	struct hostent *hp;
	struct sockaddr_in server_addr;
	struct sockaddr_in mount_server_addr;
	int msock, fsock;
	union {
		struct fhstatus nfsv2;
		struct mountres3 nfsv3;
	} status;
	int daemonized;
	char *s;
	int port;
	int mountport;
	int proto;
#if BB_MMU
	int bg = 0;
#else
	enum { bg = 0 };
#endif
	int soft;
	int intr;
	int posix;
	int nocto;
	int noac;
	int nolock;
	int retry;
	int tcp;
	int mountprog;
	int mountvers;
	int nfsprog;
	int nfsvers;
	int retval;

	find_kernel_nfs_mount_version();

	daemonized = 0;
	mounthost = NULL;
	retval = ETIMEDOUT;
	msock = fsock = -1;
	mclient = NULL;

	/* NB: hostname, mounthost, filteropts must be free()d prior to return */

	filteropts = xstrdup(filteropts); /* going to trash it later... */

	hostname = xstrdup(mp->mnt_fsname);
	/* mount_main() guarantees that ':' is there */
	s = strchr(hostname, ':');
	pathname = s + 1;
	*s = '\0';
	/* Ignore all but first hostname in replicated mounts
	   until they can be fully supported. (mack@sgi.com) */
	s = strchr(hostname, ',');
	if (s) {
		*s = '\0';
		bb_error_msg("warning: multiple hostnames not supported");
	}

	server_addr.sin_family = AF_INET;
	if (!inet_aton(hostname, &server_addr.sin_addr)) {
		hp = gethostbyname(hostname);
		if (hp == NULL) {
			bb_herror_msg("%s", hostname);
			goto fail;
		}
		if (hp->h_length > sizeof(struct in_addr)) {
			bb_error_msg("got bad hp->h_length");
			hp->h_length = sizeof(struct in_addr);
		}
		memcpy(&server_addr.sin_addr,
				hp->h_addr, hp->h_length);
	}

	memcpy(&mount_server_addr, &server_addr, sizeof(mount_server_addr));

	/* add IP address to mtab options for use when unmounting */

	if (!mp->mnt_opts) { /* TODO: actually mp->mnt_opts is never NULL */
		mp->mnt_opts = xasprintf("addr=%s", inet_ntoa(server_addr.sin_addr));
	} else {
		char *tmp = xasprintf("%s%saddr=%s", mp->mnt_opts,
					mp->mnt_opts[0] ? "," : "",
					inet_ntoa(server_addr.sin_addr));
		free(mp->mnt_opts);
		mp->mnt_opts = tmp;
	}

	/* Set default options.
	 * rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
	 * let the kernel decide.
	 * timeo is filled in after we know whether it'll be TCP or UDP. */
	memset(&data, 0, sizeof(data));
	data.retrans	= 3;
	data.acregmin	= 3;
	data.acregmax	= 60;
	data.acdirmin	= 30;
	data.acdirmax	= 60;
	data.namlen	= NAME_MAX;

	soft = 0;
	intr = 0;
	posix = 0;
	nocto = 0;
	nolock = 0;
	noac = 0;
	retry = 10000;		/* 10000 minutes ~ 1 week */
	tcp = 0;

	mountprog = MOUNTPROG;
	mountvers = 0;
	port = 0;
	mountport = 0;
	nfsprog = 100003;
	nfsvers = 0;

	/* parse options */
	if (filteropts)	for (opt = strtok(filteropts, ","); opt; opt = strtok(NULL, ",")) {
		char *opteq = strchr(opt, '=');
		if (opteq) {
			static const char options[] ALIGN1 =
				/* 0 */ "rsize\0"
				/* 1 */ "wsize\0"
				/* 2 */ "timeo\0"
				/* 3 */ "retrans\0"
				/* 4 */ "acregmin\0"
				/* 5 */ "acregmax\0"
				/* 6 */ "acdirmin\0"
				/* 7 */ "acdirmax\0"
				/* 8 */ "actimeo\0"
				/* 9 */ "retry\0"
				/* 10 */ "port\0"
				/* 11 */ "mountport\0"
				/* 12 */ "mounthost\0"
				/* 13 */ "mountprog\0"
				/* 14 */ "mountvers\0"
				/* 15 */ "nfsprog\0"
				/* 16 */ "nfsvers\0"
				/* 17 */ "vers\0"
				/* 18 */ "proto\0"
				/* 19 */ "namlen\0"
				/* 20 */ "addr\0";
			int val = xatoi_u(opteq + 1);
			*opteq = '\0';
			switch (index_in_strings(options, opt)) {
			case 0: // "rsize"
				data.rsize = val;
				break;
			case 1: // "wsize"
				data.wsize = val;
				break;
			case 2: // "timeo"
				data.timeo = val;
				break;
			case 3: // "retrans"
				data.retrans = val;
				break;
			case 4: // "acregmin"
				data.acregmin = val;
				break;
			case 5: // "acregmax"
				data.acregmax = val;
				break;
			case 6: // "acdirmin"
				data.acdirmin = val;
				break;
			case 7: // "acdirmax"
				data.acdirmax = val;
				break;
			case 8: // "actimeo"
				data.acregmin = val;
				data.acregmax = val;
				data.acdirmin = val;
				data.acdirmax = val;
				break;
			case 9: // "retry"
				retry = val;
				break;
			case 10: // "port"
				port = val;
				break;
			case 11: // "mountport"
				mountport = val;
				break;
			case 12: // "mounthost"
				mounthost = xstrndup(opteq+1,
						strcspn(opteq+1," \t\n\r,"));
				break;
			case 13: // "mountprog"
				mountprog = val;
				break;
			case 14: // "mountvers"
				mountvers = val;
				break;
			case 15: // "nfsprog"
				nfsprog = val;
				break;
			case 16: // "nfsvers"
			case 17: // "vers"
				nfsvers = val;
				break;
			case 18: // "proto"
				if (!strncmp(opteq+1, "tcp", 3))
					tcp = 1;
				else if (!strncmp(opteq+1, "udp", 3))
					tcp = 0;
				else
					bb_error_msg("warning: unrecognized proto= option");
				break;
			case 19: // "namlen"
				if (nfs_mount_version >= 2)
					data.namlen = val;
				else
					bb_error_msg("warning: option namlen is not supported\n");
				break;
			case 20: // "addr" - ignore
				break;
			default:
				bb_error_msg("unknown nfs mount parameter: %s=%d", opt, val);
				goto fail;
			}
		}
		else {
			static const char options[] ALIGN1 =
				"bg\0"
				"fg\0"
				"soft\0"
				"hard\0"
				"intr\0"
				"posix\0"
				"cto\0"
				"ac\0"
				"tcp\0"
				"udp\0"
				"lock\0";
			int val = 1;
			if (!strncmp(opt, "no", 2)) {
				val = 0;
				opt += 2;
			}
			switch (index_in_strings(options, opt)) {
			case 0: // "bg"
#if BB_MMU
				bg = val;
#endif
				break;
			case 1: // "fg"
#if BB_MMU
				bg = !val;
#endif
				break;
			case 2: // "soft"
				soft = val;
				break;
			case 3: // "hard"
				soft = !val;
				break;
			case 4: // "intr"
				intr = val;
				break;
			case 5: // "posix"
				posix = val;
				break;
			case 6: // "cto"
				nocto = !val;
				break;
			case 7: // "ac"
				noac = !val;
				break;
			case 8: // "tcp"
				tcp = val;
				break;
			case 9: // "udp"
				tcp = !val;
				break;
			case 10: // "lock"
				if (nfs_mount_version >= 3)
					nolock = !val;
				else
					bb_error_msg("warning: option nolock is not supported");
				break;
			default:
				bb_error_msg("unknown nfs mount option: %s%s", val ? "" : "no", opt);
				goto fail;
			}
		}
	}
	proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;

	data.flags = (soft ? NFS_MOUNT_SOFT : 0)
		| (intr ? NFS_MOUNT_INTR : 0)
		| (posix ? NFS_MOUNT_POSIX : 0)
		| (nocto ? NFS_MOUNT_NOCTO : 0)
		| (noac ? NFS_MOUNT_NOAC : 0);
	if (nfs_mount_version >= 2)
		data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
	if (nfs_mount_version >= 3)
		data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
	if (nfsvers > MAX_NFSPROT || mountvers > MAX_NFSPROT) {
		bb_error_msg("NFSv%d not supported", nfsvers);
		goto fail;
	}
	if (nfsvers && !mountvers)
		mountvers = (nfsvers < 3) ? 1 : nfsvers;
	if (nfsvers && nfsvers < mountvers) {
		mountvers = nfsvers;
	}

	/* Adjust options if none specified */
	if (!data.timeo)
		data.timeo = tcp ? 70 : 7;

	data.version = nfs_mount_version;

	if (vfsflags & MS_REMOUNT)
		goto do_mount;

	/*
	 * If the previous mount operation on the same host was
	 * backgrounded, and the "bg" for this mount is also set,
	 * give up immediately, to avoid the initial timeout.
	 */
	if (bg && we_saw_this_host_before(hostname)) {
		daemonized = daemonize();
		if (daemonized <= 0) { /* parent or error */
			retval = -daemonized;
			goto ret;
		}
	}

	/* create mount daemon client */
	/* See if the nfs host = mount host. */
	if (mounthost) {
		if (mounthost[0] >= '0' && mounthost[0] <= '9') {
			mount_server_addr.sin_family = AF_INET;
			mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
		} else {
			hp = gethostbyname(mounthost);
			if (hp == NULL) {
				bb_herror_msg("%s", mounthost);
				goto fail;
			} else {
				if (hp->h_length > sizeof(struct in_addr)) {
					bb_error_msg("got bad hp->h_length?");
					hp->h_length = sizeof(struct in_addr);
				}
				mount_server_addr.sin_family = AF_INET;
				memcpy(&mount_server_addr.sin_addr,
						hp->h_addr, hp->h_length);
			}
		}
	}

	/*
	 * The following loop implements the mount retries. When the mount
	 * times out, and the "bg" option is set, we background ourself
	 * and continue trying.
	 *
	 * The case where the mount point is not present and the "bg"
	 * option is set, is treated as a timeout. This is done to
	 * support nested mounts.
	 *
	 * The "retry" count specified by the user is the number of
	 * minutes to retry before giving up.
	 */
	{
		struct timeval total_timeout;
		struct timeval retry_timeout;
		struct pmap pm_mnt;
		time_t t;
		time_t prevt;
		time_t timeout;

		retry_timeout.tv_sec = 3;
		retry_timeout.tv_usec = 0;
		total_timeout.tv_sec = 20;
		total_timeout.tv_usec = 0;
		timeout = time(NULL) + 60 * retry;
		prevt = 0;
		t = 30;
 retry:
		/* be careful not to use too many CPU cycles */
		if (t - prevt < 30)
			sleep(30);

		get_mountport(&pm_mnt, &mount_server_addr,
				mountprog,
				mountvers,
				proto,
				mountport);
		nfsvers = (pm_mnt.pm_vers < 2) ? 2 : pm_mnt.pm_vers;

		/* contact the mount daemon via TCP */
		mount_server_addr.sin_port = htons(pm_mnt.pm_port);
		msock = RPC_ANYSOCK;

		switch (pm_mnt.pm_prot) {
		case IPPROTO_UDP:
			mclient = clntudp_create(&mount_server_addr,
						 pm_mnt.pm_prog,
						 pm_mnt.pm_vers,
						 retry_timeout,
						 &msock);
			if (mclient)
				break;
			mount_server_addr.sin_port = htons(pm_mnt.pm_port);
			msock = RPC_ANYSOCK;
		case IPPROTO_TCP:
			mclient = clnttcp_create(&mount_server_addr,
						 pm_mnt.pm_prog,
						 pm_mnt.pm_vers,
						 &msock, 0, 0);
			break;
		default:
			mclient = NULL;
		}
		if (!mclient) {
			if (!daemonized && prevt == 0)
				error_msg_rpc(clnt_spcreateerror(" "));
		} else {
			enum clnt_stat clnt_stat;
			/* try to mount hostname:pathname */
			mclient->cl_auth = authunix_create_default();

			/* make pointers in xdr_mountres3 NULL so
			 * that xdr_array allocates memory for us
			 */
			memset(&status, 0, sizeof(status));

			if (pm_mnt.pm_vers == 3)
				clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
					      (xdrproc_t) xdr_dirpath,
					      (caddr_t) &pathname,
					      (xdrproc_t) xdr_mountres3,
					      (caddr_t) &status,
					      total_timeout);
			else
				clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
					      (xdrproc_t) xdr_dirpath,
					      (caddr_t) &pathname,
					      (xdrproc_t) xdr_fhstatus,
					      (caddr_t) &status,
					      total_timeout);

			if (clnt_stat == RPC_SUCCESS)
				goto prepare_kernel_data; /* we're done */
			if (errno != ECONNREFUSED) {
				error_msg_rpc(clnt_sperror(mclient, " "));
				goto fail;	/* don't retry */
			}
			/* Connection refused */
			if (!daemonized && prevt == 0) /* print just once */
				error_msg_rpc(clnt_sperror(mclient, " "));
			auth_destroy(mclient->cl_auth);
			clnt_destroy(mclient);
			mclient = NULL;
			close(msock);
			msock = -1;
		}

		/* Timeout. We are going to retry... maybe */

		if (!bg)
			goto fail;
		if (!daemonized) {
			daemonized = daemonize();
			if (daemonized <= 0) { /* parent or error */
				retval = -daemonized;
				goto ret;
			}
		}
		prevt = t;
		t = time(NULL);
		if (t >= timeout)
			/* TODO error message */
			goto fail;

		goto retry;
	}

 prepare_kernel_data:

	if (nfsvers == 2) {
		if (status.nfsv2.fhs_status != 0) {
			bb_error_msg("%s:%s failed, reason given by server: %s",
				hostname, pathname,
				nfs_strerror(status.nfsv2.fhs_status));
			goto fail;
		}
		memcpy(data.root.data,
				(char *) status.nfsv2.fhstatus_u.fhs_fhandle,
				NFS_FHSIZE);
		data.root.size = NFS_FHSIZE;
		memcpy(data.old_root.data,
				(char *) status.nfsv2.fhstatus_u.fhs_fhandle,
				NFS_FHSIZE);
	} else {
		fhandle3 *my_fhandle;
		if (status.nfsv3.fhs_status != 0) {
			bb_error_msg("%s:%s failed, reason given by server: %s",
				hostname, pathname,
				nfs_strerror(status.nfsv3.fhs_status));
			goto fail;
		}
		my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
		memset(data.old_root.data, 0, NFS_FHSIZE);
		memset(&data.root, 0, sizeof(data.root));
		data.root.size = my_fhandle->fhandle3_len;
		memcpy(data.root.data,
				(char *) my_fhandle->fhandle3_val,
				my_fhandle->fhandle3_len);

		data.flags |= NFS_MOUNT_VER3;
	}

	/* create nfs socket for kernel */

	if (tcp) {
		if (nfs_mount_version < 3) {
			bb_error_msg("NFS over TCP is not supported");
			goto fail;
		}
		fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	} else
		fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (fsock < 0) {
		bb_perror_msg("nfs socket");
		goto fail;
	}
	if (bindresvport(fsock, 0) < 0) {
		bb_perror_msg("nfs bindresvport");
		goto fail;
	}
	if (port == 0) {
		server_addr.sin_port = PMAPPORT;
		port = pmap_getport(&server_addr, nfsprog, nfsvers,
					tcp ? IPPROTO_TCP : IPPROTO_UDP);
		if (port == 0)
			port = NFS_PORT;
	}
	server_addr.sin_port = htons(port);

	/* prepare data structure for kernel */

	data.fd = fsock;
	memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
	strncpy(data.hostname, hostname, sizeof(data.hostname));

	/* clean up */

	auth_destroy(mclient->cl_auth);
	clnt_destroy(mclient);
	close(msock);
	msock = -1;

	if (bg) {
		/* We must wait until mount directory is available */
		struct stat statbuf;
		int delay = 1;
		while (stat(mp->mnt_dir, &statbuf) == -1) {
			if (!daemonized) {
				daemonized = daemonize();
				if (daemonized <= 0) { /* parent or error */
	// FIXME: parent doesn't close fsock - ??!
					retval = -daemonized;
					goto ret;
				}
			}
			sleep(delay);	/* 1, 2, 4, 8, 16, 30, ... */
			delay *= 2;
			if (delay > 30)
				delay = 30;
		}
	}

 do_mount: /* perform actual mount */

	mp->mnt_type = (char*)"nfs";
	retval = mount_it_now(mp, vfsflags, (char*)&data);
	goto ret;

 fail:	/* abort */

	if (msock >= 0) {
		if (mclient) {
			auth_destroy(mclient->cl_auth);
			clnt_destroy(mclient);
		}
		close(msock);
	}
	if (fsock >= 0)
		close(fsock);

 ret:
	free(hostname);
	free(mounthost);
	free(filteropts);
	return retval;
}

#else /* !ENABLE_FEATURE_MOUNT_NFS */

/* Never called. Call should be optimized out. */
int nfsmount(struct mntent *mp, long vfsflags, char *filteropts);

#endif /* !ENABLE_FEATURE_MOUNT_NFS */

// Mount one directory.  Handles CIFS, NFS, loopback, autobind, and filesystem
// type detection.  Returns 0 for success, nonzero for failure.
// NB: mp->xxx fields may be trashed on exit
static int singlemount(struct mntent *mp, int ignore_busy)
{
	int rc = -1;
	long vfsflags;
	char *loopFile = 0, *filteropts = 0;
	llist_t *fl = 0;
	struct stat st;

	vfsflags = parse_mount_options(mp->mnt_opts, &filteropts);

	// Treat fstype "auto" as unspecified.

	if (mp->mnt_type && strcmp(mp->mnt_type, "auto") == 0)
		mp->mnt_type = NULL;

	// Might this be a virtual filesystem?

	if (ENABLE_FEATURE_MOUNT_HELPERS
	 && (strchr(mp->mnt_fsname, '#'))
	) {
		char *s, *p, *args[35];
		int n = 0;
// FIXME: does it allow execution of arbitrary commands?!
// What args[0] can end up with?
		for (s = p = mp->mnt_fsname; *s && n < 35-3; ++s) {
			if (s[0] == '#' && s[1] != '#') {
				*s = '\0';
				args[n++] = p;
				p = s + 1;
			}
		}
		args[n++] = p;
		args[n++] = mp->mnt_dir;
		args[n] = NULL;
		rc = wait4pid(xspawn(args));
		goto report_error;
	}

	// Might this be an CIFS filesystem?

	if (ENABLE_FEATURE_MOUNT_CIFS
	 && (!mp->mnt_type || strcmp(mp->mnt_type, "cifs") == 0)
	 && (mp->mnt_fsname[0] == '/' || mp->mnt_fsname[0] == '\\')
	 && mp->mnt_fsname[0] == mp->mnt_fsname[1]
	) {
		len_and_sockaddr *lsa;
		char *ip, *dotted;
		char *s;

		rc = 1;
		// Replace '/' with '\' and verify that unc points to "//server/share".

		for (s = mp->mnt_fsname; *s; ++s)
			if (*s == '/') *s = '\\';

		// get server IP

		s = strrchr(mp->mnt_fsname, '\\');
		if (s <= mp->mnt_fsname+1) goto report_error;
		*s = '\0';
		lsa = host2sockaddr(mp->mnt_fsname+2, 0);
		*s = '\\';
		if (!lsa) goto report_error;

		// insert ip=... option into string flags.

		dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
		ip = xasprintf("ip=%s", dotted);
		parse_mount_options(ip, &filteropts);

		// compose new unc '\\server-ip\share'
		// (s => slash after hostname)

		mp->mnt_fsname = xasprintf("\\\\%s%s", dotted, s);

		// lock is required
		vfsflags |= MS_MANDLOCK;

		mp->mnt_type = (char*)"cifs";
		rc = mount_it_now(mp, vfsflags, filteropts);
		if (ENABLE_FEATURE_CLEAN_UP) {
			free(mp->mnt_fsname);
			free(ip);
			free(dotted);
			free(lsa);
		}
		goto report_error;
	}

	// Might this be an NFS filesystem?

	if (ENABLE_FEATURE_MOUNT_NFS
	 && (!mp->mnt_type || !strcmp(mp->mnt_type, "nfs"))
	 && strchr(mp->mnt_fsname, ':') != NULL
	) {
		rc = nfsmount(mp, vfsflags, filteropts);
		goto report_error;
	}

	// Look at the file.  (Not found isn't a failure for remount, or for
	// a synthetic filesystem like proc or sysfs.)
	// (We use stat, not lstat, in order to allow
	// mount symlink_to_file_or_blkdev dir)

	if (!stat(mp->mnt_fsname, &st)
	 && !(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE))
	) {
		// Do we need to allocate a loopback device for it?

		if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
			loopFile = bb_simplify_path(mp->mnt_fsname);
			mp->mnt_fsname = NULL; /* will receive malloced loop dev name */
			if (set_loop(&(mp->mnt_fsname), loopFile, 0) < 0) {
				if (errno == EPERM || errno == EACCES)
					bb_error_msg(bb_msg_perm_denied_are_you_root);
				else
					bb_perror_msg("cannot setup loop device");
				return errno;
			}

		// Autodetect bind mounts

		} else if (S_ISDIR(st.st_mode) && !mp->mnt_type)
			vfsflags |= MS_BIND;
	}

	/* If we know the fstype (or don't need to), jump straight
	 * to the actual mount. */

	if (mp->mnt_type || (vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
		rc = mount_it_now(mp, vfsflags, filteropts);
	else {
		// Loop through filesystem types until mount succeeds
		// or we run out

		/* Initialize list of block backed filesystems.  This has to be
		 * done here so that during "mount -a", mounts after /proc shows up
		 * can autodetect. */

		if (!fslist) {
			fslist = get_block_backed_filesystems();
			if (ENABLE_FEATURE_CLEAN_UP && fslist)
				atexit(delete_block_backed_filesystems);
		}

		for (fl = fslist; fl; fl = fl->link) {
			mp->mnt_type = fl->data;
			rc = mount_it_now(mp, vfsflags, filteropts);
			if (!rc) break;
		}
	}

	// If mount failed, clean up loop file (if any).

	if (ENABLE_FEATURE_MOUNT_LOOP && rc && loopFile) {
		del_loop(mp->mnt_fsname);
		if (ENABLE_FEATURE_CLEAN_UP) {
			free(loopFile);
			free(mp->mnt_fsname);
		}
	}

 report_error:
	if (ENABLE_FEATURE_CLEAN_UP)
		free(filteropts);

	if (errno == EBUSY && ignore_busy)
		return 0;
	if (rc < 0)
		bb_perror_msg("mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);
	return rc;
}

// Parse options, if necessary parse fstab/mtab, and call singlemount for
// each directory to be mounted.

static const char must_be_root[] ALIGN1 = "you must be root";

int mount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mount_main(int argc, char **argv)
{
	char *cmdopts = xstrdup("");
	char *fstype = NULL;
	char *storage_path = NULL;
	char *opt_o;
	const char *fstabname;
	FILE *fstab;
	int i, j, rc = 0;
	unsigned opt;
	struct mntent mtpair[2], *mtcur = mtpair;
	SKIP_DESKTOP(const int nonroot = 0;)

	USE_DESKTOP( int nonroot = ) sanitize_env_if_suid();

	// Parse long options, like --bind and --move.  Note that -o option
	// and --option are synonymous.  Yes, this means --remount,rw works.

	for (i = j = 0; i < argc; i++) {
		if (argv[i][0] == '-' && argv[i][1] == '-') {
			append_mount_options(&cmdopts, argv[i]+2);
		} else argv[j++] = argv[i];
	}
	argv[j] = NULL;
	argc = j;

	// Parse remaining options

#if ENABLE_FEATURE_MOUNT_VERBOSE
	opt_complementary = "vv"; // -v is a counter
#endif
	opt = getopt32(argv, OPTION_STR, &opt_o, &fstype
			USE_FEATURE_MOUNT_VERBOSE(, &verbose));
	if (opt & OPT_o) append_mount_options(&cmdopts, opt_o); // -o
	if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
	if (opt & OPT_w) append_mount_options(&cmdopts, "rw"); // -w
	argv += optind;
	argc -= optind;

	// Three or more non-option arguments?  Die with a usage message.

	if (argc > 2) bb_show_usage();

	// If we have no arguments, show currently mounted filesystems

	if (!argc) {
		if (!(opt & OPT_a)) {
			FILE *mountTable = setmntent(bb_path_mtab_file, "r");

			if (!mountTable) bb_error_msg_and_die("no %s", bb_path_mtab_file);

			while (getmntent_r(mountTable, &mtpair[0], getmntent_buf,
								sizeof(getmntent_buf)))
			{
				// Don't show rootfs. FIXME: why??
				// util-linux 2.12a happily shows rootfs...
				//if (!strcmp(mtpair->mnt_fsname, "rootfs")) continue;

				if (!fstype || !strcmp(mtpair->mnt_type, fstype))
					printf("%s on %s type %s (%s)\n", mtpair->mnt_fsname,
							mtpair->mnt_dir, mtpair->mnt_type,
							mtpair->mnt_opts);
			}
			if (ENABLE_FEATURE_CLEAN_UP) endmntent(mountTable);
			return EXIT_SUCCESS;
		}
	} else storage_path = bb_simplify_path(argv[0]);

	// When we have two arguments, the second is the directory and we can
	// skip looking at fstab entirely.  We can always abspath() the directory
	// argument when we get it.

	if (argc == 2) {
		if (nonroot)
			bb_error_msg_and_die(must_be_root);
		mtpair->mnt_fsname = argv[0];
		mtpair->mnt_dir = argv[1];
		mtpair->mnt_type = fstype;
		mtpair->mnt_opts = cmdopts;
		if (ENABLE_FEATURE_MOUNT_LABEL) {
			resolve_mount_spec(&mtpair->mnt_fsname);
		}
		rc = singlemount(mtpair, 0);
		goto clean_up;
	}

	i = parse_mount_options(cmdopts, 0); // FIXME: should be "long", not "int"
	if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
		bb_error_msg_and_die(must_be_root);

	// If we have a shared subtree flag, don't worry about fstab or mtab.

	if (ENABLE_FEATURE_MOUNT_FLAGS
	 && (i & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
	) {
		rc = verbose_mount("", argv[0], "", i, "");
		if (rc) bb_simple_perror_msg_and_die(argv[0]);
		goto clean_up;
	}

	// Open either fstab or mtab

	fstabname = "/etc/fstab";
	if (i & MS_REMOUNT) {
		fstabname = bb_path_mtab_file;
	}
	fstab = setmntent(fstabname, "r");
	if (!fstab)
		bb_perror_msg_and_die("cannot read %s", fstabname);

	// Loop through entries until we find what we're looking for.

	memset(mtpair, 0, sizeof(mtpair));
	for (;;) {
		struct mntent *mtnext = (mtcur==mtpair ? mtpair+1 : mtpair);

		// Get next fstab entry

		if (!getmntent_r(fstab, mtcur, getmntent_buf
					+ (mtcur==mtpair ? sizeof(getmntent_buf)/2 : 0),
				sizeof(getmntent_buf)/2))
		{
			// Were we looking for something specific?

			if (argc) {

				// If we didn't find anything, complain.

				if (!mtnext->mnt_fsname)
					bb_error_msg_and_die("can't find %s in %s",
						argv[0], fstabname);

				mtcur = mtnext;
				if (nonroot) {
					// fstab must have "users" or "user"
					if (!(parse_mount_options(mtcur->mnt_opts, 0) & MOUNT_USERS))
						bb_error_msg_and_die(must_be_root);
				}

				// Mount the last thing we found.

				mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
				append_mount_options(&(mtcur->mnt_opts), cmdopts);
				if (ENABLE_FEATURE_MOUNT_LABEL) {
					resolve_mount_spec(&mtpair->mnt_fsname);
				}
				rc = singlemount(mtcur, 0);
				free(mtcur->mnt_opts);
			}
			goto clean_up;
		}

		/* If we're trying to mount something specific and this isn't it,
		 * skip it.  Note we must match both the exact text in fstab (ala
		 * "proc") or a full path from root */

		if (argc) {

			// Is this what we're looking for?

			if (strcmp(argv[0], mtcur->mnt_fsname) &&
			   strcmp(storage_path, mtcur->mnt_fsname) &&
			   strcmp(argv[0], mtcur->mnt_dir) &&
			   strcmp(storage_path, mtcur->mnt_dir)) continue;

			// Remember this entry.  Something later may have overmounted
			// it, and we want the _last_ match.

			mtcur = mtnext;

		// If we're mounting all.

		} else {
			// Do we need to match a filesystem type?
			if (fstype && match_fstype(mtcur, fstype))
				continue;

			// Skip noauto and swap anyway.

			if (parse_mount_options(mtcur->mnt_opts, 0) & (MOUNT_NOAUTO | MOUNT_SWAP))
				continue;

			// No, mount -a won't mount anything,
			// even user mounts, for mere humans.

			if (nonroot)
				bb_error_msg_and_die(must_be_root);

			// Mount this thing.
			if (ENABLE_FEATURE_MOUNT_LABEL)
				resolve_mount_spec(&mtpair->mnt_fsname);

			// NFS mounts want this to be xrealloc-able
			mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
			if (singlemount(mtcur, 1)) {
				/* Count number of failed mounts */
				rc++;
			}
			free(mtcur->mnt_opts);
		}
	}
	if (ENABLE_FEATURE_CLEAN_UP) endmntent(fstab);

 clean_up:

	if (ENABLE_FEATURE_CLEAN_UP) {
		free(storage_path);
		free(cmdopts);
	}

	return rc;
}