summaryrefslogtreecommitdiff
path: root/networking/wget.c
blob: a9a0f5f8cb14e097c7bd3c42446d5819d11251ff (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
/* vi: set sw=4 ts=4: */
/*
 * wget - retrieve a file using HTTP or FTP
 *
 * Chip Rosenthal Covad Communications <chip@laserlink.net>
 * Licensed under GPLv2, see file LICENSE in this source tree.
 *
 * Copyright (C) 2010 Bradley M. Kuhn <bkuhn@ebb.org>
 * Kuhn's copyrights are licensed GPLv2-or-later.  File as a whole remains GPLv2.
 */
//config:config WGET
//config:	bool "wget (35 kb)"
//config:	default y
//config:	help
//config:	wget is a utility for non-interactive download of files from HTTP
//config:	and FTP servers.
//config:
//config:config FEATURE_WGET_LONG_OPTIONS
//config:	bool "Enable long options"
//config:	default y
//config:	depends on WGET && LONG_OPTS
//config:
//config:config FEATURE_WGET_STATUSBAR
//config:	bool "Enable progress bar (+2k)"
//config:	default y
//config:	depends on WGET
//config:
//config:config FEATURE_WGET_AUTHENTICATION
//config:	bool "Enable HTTP authentication"
//config:	default y
//config:	depends on WGET
//config:	help
//config:	Support authenticated HTTP transfers.
//config:
//config:config FEATURE_WGET_TIMEOUT
//config:	bool "Enable timeout option -T SEC"
//config:	default y
//config:	depends on WGET
//config:	help
//config:	Supports network read and connect timeouts for wget,
//config:	so that wget will give up and timeout, through the -T
//config:	command line option.
//config:
//config:	Currently only connect and network data read timeout are
//config:	supported (i.e., timeout is not applied to the DNS query). When
//config:	FEATURE_WGET_LONG_OPTIONS is also enabled, the --timeout option
//config:	will work in addition to -T.
//config:
//config:config FEATURE_WGET_HTTPS
//config:	bool "Support HTTPS using internal TLS code"
//it also enables FTPS support, but it's not well tested yet
//config:	default y
//config:	depends on WGET
//config:	select TLS
//config:	help
//config:	wget will use internal TLS code to connect to https:// URLs.
//config:	Note:
//config:	On NOMMU machines, ssl_helper applet should be available
//config:	in the $PATH for this to work. Make sure to select that applet.
//config:
//config:	Note: currently, TLS code only makes TLS I/O work, it
//config:	does *not* check that the peer is who it claims to be, etc.
//config:	IOW: it uses peer-supplied public keys to establish encryption
//config:	and signing keys, then encrypts and signs outgoing data and
//config:	decrypts incoming data.
//config:	It does not check signature hashes on the incoming data:
//config:	this means that attackers manipulating TCP packets can
//config:	send altered data and we unknowingly receive garbage.
//config:	(This check might be relatively easy to add).
//config:	It does not check public key's certificate:
//config:	this means that the peer may be an attacker impersonating
//config:	the server we think we are talking to.
//config:
//config:	If you think this is unacceptable, consider this. As more and more
//config:	servers switch to HTTPS-only operation, without such "crippled"
//config:	TLS code it is *impossible* to simply download a kernel source
//config:	from kernel.org. Which can in real world translate into
//config:	"my small automatic tooling to build cross-compilers from sources
//config:	no longer works, I need to additionally keep a local copy
//config:	of ~4 megabyte source tarball of a SSL library and ~2 megabyte
//config:	source of wget, need to compile and built both before I can
//config:	download anything. All this despite the fact that the build
//config:	is done in a QEMU sandbox on a machine with absolutely nothing
//config:	worth stealing, so I don't care if someone would go to a lot
//config:	of trouble to intercept my HTTPS download to send me an altered
//config:	kernel tarball".
//config:
//config:	If you still think this is unacceptable, send patches.
//config:
//config:	If you still think this is unacceptable, do not want to send
//config:	patches, but do want to waste bandwidth expaining how wrong
//config:	it is, you will be ignored.
//config:
//config:config FEATURE_WGET_OPENSSL
//config:	bool "Try to connect to HTTPS using openssl"
//config:	default y
//config:	depends on WGET
//config:	help
//config:	Try to use openssl to handle HTTPS.
//config:
//config:	OpenSSL has a simple SSL client for debug purposes.
//config:	If you select this option, wget will effectively run:
//config:	"openssl s_client -quiet -connect hostname:443
//config:	-servername hostname 2>/dev/null" and pipe its data
//config:	through it. -servername is not used if hostname is numeric.
//config:	Note inconvenient API: host resolution is done twice,
//config:	and there is no guarantee openssl's idea of IPv6 address
//config:	format is the same as ours.
//config:	Another problem is that s_client prints debug information
//config:	to stderr, and it needs to be suppressed. This means
//config:	all error messages get suppressed too.
//config:	openssl is also a big binary, often dynamically linked
//config:	against ~15 libraries.
//config:
//config:	If openssl can't be executed, internal TLS code will be used
//config:	(if you enabled it); if openssl can be executed but fails later,
//config:	wget can't detect this, and download will fail.

//applet:IF_WGET(APPLET(wget, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_WGET) += wget.o

//usage:#define wget_trivial_usage
//usage:	IF_FEATURE_WGET_LONG_OPTIONS(
//usage:       "[-c|--continue] [--spider] [-q|--quiet] [-O|--output-document FILE]\n"
//usage:       "	[--header 'header: value'] [-Y|--proxy on/off] [-P DIR]\n"
/* Since we ignore these opts, we don't show them in --help */
/* //usage:    "	[--no-check-certificate] [--no-cache] [--passive-ftp] [-t TRIES]" */
/* //usage:    "	[-nv] [-nc] [-nH] [-np]" */
//usage:       "	[-S|--server-response] [-U|--user-agent AGENT]" IF_FEATURE_WGET_TIMEOUT(" [-T SEC]") " URL..."
//usage:	)
//usage:	IF_NOT_FEATURE_WGET_LONG_OPTIONS(
//usage:       "[-cq] [-O FILE] [-Y on/off] [-P DIR] [-S] [-U AGENT]"
//usage:			IF_FEATURE_WGET_TIMEOUT(" [-T SEC]") " URL..."
//usage:	)
//usage:#define wget_full_usage "\n\n"
//usage:       "Retrieve files via HTTP or FTP\n"
//usage:	IF_FEATURE_WGET_LONG_OPTIONS(
//usage:     "\n	--spider	Only check URL existence: $? is 0 if exists"
///////:     "\n	--no-check-certificate	Don't validate the server's certificate"
//usage:	)
//usage:     "\n	-c		Continue retrieval of aborted transfer"
//usage:     "\n	-q		Quiet"
//usage:     "\n	-P DIR		Save to DIR (default .)"
//usage:     "\n	-S    		Show server response"
//usage:	IF_FEATURE_WGET_TIMEOUT(
//usage:     "\n	-T SEC		Network read timeout is SEC seconds"
//usage:	)
//usage:     "\n	-O FILE		Save to FILE ('-' for stdout)"
//usage:     "\n	-U STR		Use STR for User-Agent header"
//usage:     "\n	-Y on/off	Use proxy"

#include "libbb.h"

#if 0
# define log_io(...) bb_error_msg(__VA_ARGS__)
# define SENDFMT(fp, fmt, ...) \
	do { \
		log_io("> " fmt, ##__VA_ARGS__); \
		fprintf(fp, fmt, ##__VA_ARGS__); \
	} while (0);
#else
# define log_io(...) ((void)0)
# define SENDFMT(fp, fmt, ...) fprintf(fp, fmt, ##__VA_ARGS__)
#endif


#define SSL_SUPPORTED (ENABLE_FEATURE_WGET_OPENSSL || ENABLE_FEATURE_WGET_HTTPS)

struct host_info {
	char *allocated;
	const char *path;
	char       *user;
	const char *protocol;
	char       *host;
	int         port;
};
static const char P_FTP[] ALIGN1 = "ftp";
static const char P_HTTP[] ALIGN1 = "http";
#if SSL_SUPPORTED
# if ENABLE_FEATURE_WGET_HTTPS
static const char P_FTPS[] ALIGN1 = "ftps";
# endif
static const char P_HTTPS[] ALIGN1 = "https";
#endif

#if ENABLE_FEATURE_WGET_LONG_OPTIONS
/* User-specified headers prevent using our corresponding built-in headers.  */
enum {
	HDR_HOST          = (1<<0),
	HDR_USER_AGENT    = (1<<1),
	HDR_RANGE         = (1<<2),
	HDR_AUTH          = (1<<3) * ENABLE_FEATURE_WGET_AUTHENTICATION,
	HDR_PROXY_AUTH    = (1<<4) * ENABLE_FEATURE_WGET_AUTHENTICATION,
};
static const char wget_user_headers[] ALIGN1 =
	"Host:\0"
	"User-Agent:\0"
	"Range:\0"
# if ENABLE_FEATURE_WGET_AUTHENTICATION
	"Authorization:\0"
	"Proxy-Authorization:\0"
# endif
	;
# define USR_HEADER_HOST       (G.user_headers & HDR_HOST)
# define USR_HEADER_USER_AGENT (G.user_headers & HDR_USER_AGENT)
# define USR_HEADER_RANGE      (G.user_headers & HDR_RANGE)
# define USR_HEADER_AUTH       (G.user_headers & HDR_AUTH)
# define USR_HEADER_PROXY_AUTH (G.user_headers & HDR_PROXY_AUTH)
#else /* No long options, no user-headers :( */
# define USR_HEADER_HOST       0
# define USR_HEADER_USER_AGENT 0
# define USR_HEADER_RANGE      0
# define USR_HEADER_AUTH       0
# define USR_HEADER_PROXY_AUTH 0
#endif

/* Globals */
struct globals {
	off_t content_len;        /* Content-length of the file */
	off_t beg_range;          /* Range at which continue begins */
#if ENABLE_FEATURE_WGET_STATUSBAR
	off_t transferred;        /* Number of bytes transferred so far */
	const char *curfile;      /* Name of current file being transferred */
	bb_progress_t pmt;
#endif
	char *dir_prefix;
#if ENABLE_FEATURE_WGET_LONG_OPTIONS
	char *post_data;
	char *extra_headers;
	unsigned char user_headers; /* Headers mentioned by the user */
#endif
	char *fname_out;        /* where to direct output (-O) */
	const char *proxy_flag; /* Use proxies if env vars are set */
	const char *user_agent; /* "User-Agent" header field */
#if ENABLE_FEATURE_WGET_TIMEOUT
	unsigned timeout_seconds;
	bool die_if_timed_out;
#endif
	int output_fd;
	int o_flags;
	smallint chunked;         /* chunked transfer encoding */
	smallint got_clen;        /* got content-length: from server  */
	/* Local downloads do benefit from big buffer.
	 * With 512 byte buffer, it was measured to be
	 * an order of magnitude slower than with big one.
	 */
	uint64_t just_to_align_next_member;
	char wget_buf[CONFIG_FEATURE_COPYBUF_KB*1024];
} FIX_ALIASING;
#define G (*ptr_to_globals)
#define INIT_G() do { \
	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)
#define FINI_G() do { \
	FREE_PTR_TO_GLOBALS(); \
} while (0)


/* Must match option string! */
enum {
	WGET_OPT_CONTINUE   = (1 << 0),
	WGET_OPT_QUIET      = (1 << 1),
	WGET_OPT_SERVER_RESPONSE = (1 << 2),
	WGET_OPT_OUTNAME    = (1 << 3),
	WGET_OPT_PREFIX     = (1 << 4),
	WGET_OPT_PROXY      = (1 << 5),
	WGET_OPT_USER_AGENT = (1 << 6),
	WGET_OPT_NETWORK_READ_TIMEOUT = (1 << 7),
	WGET_OPT_RETRIES    = (1 << 8),
	WGET_OPT_nsomething = (1 << 9),
	WGET_OPT_HEADER     = (1 << 10) * ENABLE_FEATURE_WGET_LONG_OPTIONS,
	WGET_OPT_POST_DATA  = (1 << 11) * ENABLE_FEATURE_WGET_LONG_OPTIONS,
	WGET_OPT_SPIDER     = (1 << 12) * ENABLE_FEATURE_WGET_LONG_OPTIONS,
	WGET_OPT_NO_CHECK_CERT = (1 << 13) * ENABLE_FEATURE_WGET_LONG_OPTIONS,
};

enum {
	PROGRESS_START = -1,
	PROGRESS_END   = 0,
	PROGRESS_BUMP  = 1,
};
#if ENABLE_FEATURE_WGET_STATUSBAR
static void progress_meter(int flag)
{
	if (option_mask32 & WGET_OPT_QUIET)
		return;

	if (flag == PROGRESS_START)
		bb_progress_init(&G.pmt, G.curfile);

	bb_progress_update(&G.pmt,
			G.beg_range,
			G.transferred,
			(G.chunked || !G.got_clen) ? 0 : G.beg_range + G.transferred + G.content_len
	);

	if (flag == PROGRESS_END) {
		bb_progress_free(&G.pmt);
		bb_putchar_stderr('\n');
		G.transferred = 0;
	}
}
#else
static ALWAYS_INLINE void progress_meter(int flag UNUSED_PARAM) { }
#endif


/* IPv6 knows scoped address types i.e. link and site local addresses. Link
 * local addresses can have a scope identifier to specify the
 * interface/link an address is valid on (e.g. fe80::1%eth0). This scope
 * identifier is only valid on a single node.
 *
 * RFC 4007 says that the scope identifier MUST NOT be sent across the wire,
 * unless all nodes agree on the semantic. Apache e.g. regards zone identifiers
 * in the Host header as invalid requests, see
 * https://issues.apache.org/bugzilla/show_bug.cgi?id=35122
 */
static void strip_ipv6_scope_id(char *host)
{
	char *scope, *cp;

	/* bbox wget actually handles IPv6 addresses without [], like
	 * wget "http://::1/xxx", but this is not standard.
	 * To save code, _here_ we do not support it. */

	if (host[0] != '[')
		return; /* not IPv6 */

	scope = strchr(host, '%');
	if (!scope)
		return;

	/* Remove the IPv6 zone identifier from the host address */
	cp = strchr(host, ']');
	if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
		/* malformed address (not "[xx]:nn" or "[xx]") */
		return;
	}

	/* cp points to "]...", scope points to "%eth0]..." */
	overlapping_strcpy(scope, cp);
}

#if ENABLE_FEATURE_WGET_AUTHENTICATION
/* Base64-encode character string. */
static char *base64enc(const char *str)
{
	unsigned len = strlen(str);
	if (len > sizeof(G.wget_buf)/4*3 - 10) /* paranoia */
		len = sizeof(G.wget_buf)/4*3 - 10;
	bb_uuencode(G.wget_buf, str, len, bb_uuenc_tbl_base64);
	return G.wget_buf;
}
#endif

#if ENABLE_FEATURE_WGET_TIMEOUT
static void alarm_handler(int sig UNUSED_PARAM)
{
	/* This is theoretically unsafe (uses stdio and malloc in signal handler) */
	if (G.die_if_timed_out)
		bb_error_msg_and_die("download timed out");
}
static void set_alarm(void)
{
	if (G.timeout_seconds) {
		alarm(G.timeout_seconds);
		G.die_if_timed_out = 1;
	}
}
# define clear_alarm() ((void)(G.die_if_timed_out = 0))
#else
# define set_alarm()   ((void)0)
# define clear_alarm() ((void)0)
#endif

#if ENABLE_FEATURE_WGET_OPENSSL
/*
 * is_ip_address() attempts to verify whether or not a string
 * contains an IPv4 or IPv6 address (vs. an FQDN).  The result
 * of inet_pton() can be used to determine this.
 *
 * TODO add proper error checking when inet_pton() returns -1
 * (some form of system error has occurred, and errno is set)
 */
static int is_ip_address(const char *string)
{
	struct sockaddr_in sa;

	int result = inet_pton(AF_INET, string, &(sa.sin_addr));
# if ENABLE_FEATURE_IPV6
	if (result == 0) {
		struct sockaddr_in6 sa6;
		result = inet_pton(AF_INET6, string, &(sa6.sin6_addr));
	}
# endif
	return (result == 1);
}
#endif

static FILE *open_socket(len_and_sockaddr *lsa)
{
	int fd;
	FILE *fp;

	set_alarm();
	fd = xconnect_stream(lsa);
	clear_alarm();

	/* glibc 2.4 seems to try seeking on it - ??! */
	/* hopefully it understands what ESPIPE means... */
	fp = fdopen(fd, "r+");
	if (!fp)
		bb_die_memory_exhausted();

	return fp;
}

/* We balk at any control chars in other side's messages.
 * This prevents nasty surprises (e.g. ESC sequences) in "Location:" URLs
 * and error messages.
 *
 * The only exception is tabs, which are converted to (one) space:
 * HTTP's "headers: <whitespace> values" may have those.
 */
static char* sanitize_string(char *s)
{
	unsigned char *p = (void *) s;
	while (*p) {
		if (*p < ' ') {
			if (*p != '\t')
				break;
			*p = ' ';
		}
		p++;
	}
	*p = '\0';
	return s;
}

/* Returns '\n' if it was seen, else '\0'. Trims at first '\r' or '\n' */
static char fgets_trim_sanitize(FILE *fp, const char *fmt)
{
	char c;
	char *buf_ptr;

	set_alarm();
	if (fgets(G.wget_buf, sizeof(G.wget_buf), fp) == NULL)
		bb_perror_msg_and_die("error getting response");
	clear_alarm();

	buf_ptr = strchrnul(G.wget_buf, '\n');
	c = *buf_ptr;
#if 1
	/* Disallow any control chars: trim at first char < 0x20 */
	sanitize_string(G.wget_buf);
#else
	*buf_ptr = '\0';
	buf_ptr = strchrnul(G.wget_buf, '\r');
	*buf_ptr = '\0';
#endif

	log_io("< %s", G.wget_buf);

	if (fmt && (option_mask32 & WGET_OPT_SERVER_RESPONSE))
		fprintf(stderr, fmt, G.wget_buf);

	return c;
}

static int ftpcmd(const char *s1, const char *s2, FILE *fp)
{
	int result;
	if (s1) {
		if (!s2)
			s2 = "";
		fprintf(fp, "%s%s\r\n", s1, s2);
		/* With --server-response, wget also shows its ftp commands */
		if (option_mask32 & WGET_OPT_SERVER_RESPONSE)
			fprintf(stderr, "--> %s%s\n\n", s1, s2);
		fflush(fp);
		log_io("> %s%s", s1, s2);
	}

	/* Read until "Nxx something" is received */
	G.wget_buf[3] = 0;
	do {
		fgets_trim_sanitize(fp, "%s\n");
	} while (!isdigit(G.wget_buf[0]) || G.wget_buf[3] != ' ');

	G.wget_buf[3] = '\0';
	result = xatoi_positive(G.wget_buf);
	G.wget_buf[3] = ' ';
	return result;
}

static void parse_url(const char *src_url, struct host_info *h)
{
	char *url, *p, *sp;

	free(h->allocated);
	h->allocated = url = xstrdup(src_url);

	h->protocol = P_FTP;
	p = strstr(url, "://");
	if (p) {
		*p = '\0';
		h->host = p + 3;
		if (strcmp(url, P_FTP) == 0) {
			h->port = bb_lookup_std_port(P_FTP, "tcp", 21);
		} else
#if SSL_SUPPORTED
# if ENABLE_FEATURE_WGET_HTTPS
		if (strcmp(url, P_FTPS) == 0) {
			h->port = bb_lookup_std_port(P_FTPS, "tcp", 990);
			h->protocol = P_FTPS;
		} else
# endif
		if (strcmp(url, P_HTTPS) == 0) {
			h->port = bb_lookup_std_port(P_HTTPS, "tcp", 443);
			h->protocol = P_HTTPS;
		} else
#endif
		if (strcmp(url, P_HTTP) == 0) {
 http:
			h->port = bb_lookup_std_port(P_HTTP, "tcp", 80);
			h->protocol = P_HTTP;
		} else {
			*p = ':';
			bb_error_msg_and_die("not an http or ftp url: %s", url);
		}
	} else {
		// GNU wget is user-friendly and falls back to http://
		h->host = url;
		goto http;
	}

	// FYI:
	// "Real" wget 'http://busybox.net?var=a/b' sends this request:
	//   'GET /?var=a/b HTTP/1.0'
	//   and saves 'index.html?var=a%2Fb' (we save 'b')
	// wget 'http://busybox.net?login=john@doe':
	//   request: 'GET /?login=john@doe HTTP/1.0'
	//   saves: 'index.html?login=john@doe' (we save 'login=john@doe')
	// wget 'http://busybox.net#test/test':
	//   request: 'GET / HTTP/1.0'
	//   saves: 'index.html' (we save 'test')
	//
	// We also don't add unique .N suffix if file exists...
	sp = strchr(h->host, '/');
	p = strchr(h->host, '?'); if (!sp || (p && sp > p)) sp = p;
	p = strchr(h->host, '#'); if (!sp || (p && sp > p)) sp = p;
	if (!sp) {
		h->path = "";
	} else if (*sp == '/') {
		*sp = '\0';
		h->path = sp + 1;
	} else {
		// sp points to '#' or '?'
		// Note:
		// http://busybox.net?login=john@doe is a valid URL
		// (without '/' between ".net" and "?"),
		// can't store NUL at sp[-1] - this destroys hostname.
		*sp++ = '\0';
		h->path = sp;
	}

	sp = strrchr(h->host, '@');
	if (sp != NULL) {
		// URL-decode "user:password" string before base64-encoding:
		// wget http://test:my%20pass@example.com should send
		// Authorization: Basic dGVzdDpteSBwYXNz
		// which decodes to "test:my pass".
		// Standard wget and curl do this too.
		*sp = '\0';
		free(h->user);
		h->user = xstrdup(percent_decode_in_place(h->host, /*strict:*/ 0));
		h->host = sp + 1;
	}
	/* else: h->user remains NULL, or as set by original request
	 * before redirect (if we are here after a redirect).
	 */
}

static char *get_sanitized_hdr(FILE *fp)
{
	char *s, *hdrval;
	int c;

	/* retrieve header line */
	c = fgets_trim_sanitize(fp, "  %s\n");

	/* end of the headers? */
	if (G.wget_buf[0] == '\0')
		return NULL;

	/* convert the header name to lower case */
	for (s = G.wget_buf; isalnum(*s) || *s == '-' || *s == '.' || *s == '_'; ++s) {
		/*
		 * No-op for 20-3f and 60-7f. "0-9a-z-." are in these ranges.
		 * 40-5f range ("@A-Z[\]^_") maps to 60-7f.
		 * "A-Z" maps to "a-z".
		 * "@[\]" can't occur in header names.
		 * "^_" maps to "~,DEL" (which is wrong).
		 * "^" was never seen yet, "_" was seen from web.archive.org
		 * (x-archive-orig-x_commoncrawl_Signature: HEXSTRING).
		 */
		*s |= 0x20;
	}

	/* verify we are at the end of the header name */
	if (*s != ':')
		bb_error_msg_and_die("bad header line: %s", G.wget_buf);

	/* locate the start of the header value */
	*s++ = '\0';
	hdrval = skip_whitespace(s);

	if (c != '\n') {
		/* Rats! The buffer isn't big enough to hold the entire header value */
		while (c = getc(fp), c != EOF && c != '\n')
			continue;
	}

	return hdrval;
}

static void reset_beg_range_to_zero(void)
{
	bb_error_msg("restart failed");
	G.beg_range = 0;
	xlseek(G.output_fd, 0, SEEK_SET);
	/* Done at the end instead: */
	/* ftruncate(G.output_fd, 0); */
}

#if ENABLE_FEATURE_WGET_OPENSSL
static int spawn_https_helper_openssl(const char *host, unsigned port)
{
	char *allocated = NULL;
	char *servername;
	int sp[2];
	int pid;
	IF_FEATURE_WGET_HTTPS(volatile int child_failed = 0;)

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) != 0)
		/* Kernel can have AF_UNIX support disabled */
		bb_perror_msg_and_die("socketpair");

	if (!strchr(host, ':'))
		host = allocated = xasprintf("%s:%u", host, port);
	servername = xstrdup(host);
	strrchr(servername, ':')[0] = '\0';

	fflush_all();
	pid = xvfork();
	if (pid == 0) {
		/* Child */
		char *argv[8];

		close(sp[0]);
		xmove_fd(sp[1], 0);
		xdup2(0, 1);
		/*
		 * openssl s_client -quiet -connect www.kernel.org:443 2>/dev/null
		 * It prints some debug stuff on stderr, don't know how to suppress it.
		 * Work around by dev-nulling stderr. We lose all error messages :(
		 */
		xmove_fd(2, 3);
		xopen("/dev/null", O_RDWR);
		memset(&argv, 0, sizeof(argv));
		argv[0] = (char*)"openssl";
		argv[1] = (char*)"s_client";
		argv[2] = (char*)"-quiet";
		argv[3] = (char*)"-connect";
		argv[4] = (char*)host;
		/*
		 * Per RFC 6066 Section 3, the only permitted values in the
		 * TLS server_name (SNI) field are FQDNs (DNS hostnames).
		 * IPv4 and IPv6 addresses, port numbers are not allowed.
		 */
		if (!is_ip_address(servername)) {
			argv[5] = (char*)"-servername";
			argv[6] = (char*)servername;
		}

		BB_EXECVP(argv[0], argv);
		xmove_fd(3, 2);
# if ENABLE_FEATURE_WGET_HTTPS
		child_failed = 1;
		xfunc_die();
# else
		bb_perror_msg_and_die("can't execute '%s'", argv[0]);
# endif
		/* notreached */
	}

	/* Parent */
	free(servername);
	free(allocated);
	close(sp[1]);
# if ENABLE_FEATURE_WGET_HTTPS
	if (child_failed) {
		close(sp[0]);
		return -1;
	}
# endif
	return sp[0];
}
#endif

#if ENABLE_FEATURE_WGET_HTTPS
static void spawn_ssl_client(const char *host, int network_fd, int flags)
{
	int sp[2];
	int pid;
	char *servername, *p;

	if (!(option_mask32 & WGET_OPT_NO_CHECK_CERT)) {
		bb_error_msg("note: TLS certificate validation not implemented");
		option_mask32 |= WGET_OPT_NO_CHECK_CERT;
	}

	servername = xstrdup(host);
	p = strrchr(servername, ':');
	if (p) *p = '\0';

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) != 0)
		/* Kernel can have AF_UNIX support disabled */
		bb_perror_msg_and_die("socketpair");

	fflush_all();
	pid = BB_MMU ? xfork() : xvfork();
	if (pid == 0) {
		/* Child */
		close(sp[0]);
		xmove_fd(sp[1], 0);
		xdup2(0, 1);
		if (BB_MMU) {
			tls_state_t *tls = new_tls_state();
			tls->ifd = tls->ofd = network_fd;
			tls_handshake(tls, servername);
			tls_run_copy_loop(tls, flags);
			exit(0);
		} else {
			char *argv[6];

			xmove_fd(network_fd, 3);
			argv[0] = (char*)"ssl_client";
			argv[1] = (char*)"-s3";
			//TODO: if (!is_ip_address(servername))...
			argv[2] = (char*)"-n";
			argv[3] = servername;
			argv[4] = (flags & TLSLOOP_EXIT_ON_LOCAL_EOF ? (char*)"-e" : NULL);
			argv[5] = NULL;
			BB_EXECVP(argv[0], argv);
			bb_perror_msg_and_die("can't execute '%s'", argv[0]);
		}
		/* notreached */
	}

	/* Parent */
	free(servername);
	close(sp[1]);
	xmove_fd(sp[0], network_fd);
}
#endif

static FILE* prepare_ftp_session(FILE **dfpp, struct host_info *target, len_and_sockaddr *lsa)
{
	FILE *sfp;
	char *pass;
	int port;

	sfp = open_socket(lsa);
#if ENABLE_FEATURE_WGET_HTTPS
	if (target->protocol == P_FTPS)
		spawn_ssl_client(target->host, fileno(sfp), TLSLOOP_EXIT_ON_LOCAL_EOF);
#endif

	if (ftpcmd(NULL, NULL, sfp) != 220)
		bb_error_msg_and_die("%s", G.wget_buf);
		/* note: ftpcmd() sanitizes G.wget_buf, ok to print */

	/* Split username:password pair */
	pass = (char*)"busybox"; /* password for "anonymous" */
	if (target->user) {
		pass = strchr(target->user, ':');
		if (pass)
			*pass++ = '\0';
	}

	/* Log in */
	switch (ftpcmd("USER ", target->user ?: "anonymous", sfp)) {
	case 230:
		break;
	case 331:
		if (ftpcmd("PASS ", pass, sfp) == 230)
			break;
		/* fall through (failed login) */
	default:
		bb_error_msg_and_die("ftp login: %s", G.wget_buf);
	}

	ftpcmd("TYPE I", NULL, sfp);

	/* Query file size */
	if (ftpcmd("SIZE ", target->path, sfp) == 213) {
		G.content_len = BB_STRTOOFF(G.wget_buf + 4, NULL, 10);
		if (G.content_len < 0 || errno) {
			bb_error_msg_and_die("bad SIZE value '%s'", G.wget_buf + 4);
		}
		G.got_clen = 1;
	}

	/* Enter passive mode */
	if (ENABLE_FEATURE_IPV6 && ftpcmd("EPSV", NULL, sfp) == 229) {
		/* good */
	} else
	if (ftpcmd("PASV", NULL, sfp) != 227) {
 pasv_error:
		bb_error_msg_and_die("bad response to %s: %s", "PASV", G.wget_buf);
	}
	port = parse_pasv_epsv(G.wget_buf);
	if (port < 0)
		goto pasv_error;

	set_nport(&lsa->u.sa, htons(port));

	*dfpp = open_socket(lsa);

#if ENABLE_FEATURE_WGET_HTTPS
	if (target->protocol == P_FTPS) {
		/* "PROT P" enables encryption of data stream.
		 * Without it (or with "PROT C"), data is sent unencrypted.
		 */
		if (ftpcmd("PROT P", NULL, sfp) == 200)
			spawn_ssl_client(target->host, fileno(*dfpp), /*flags*/ 0);
	}
#endif

	if (G.beg_range != 0) {
		sprintf(G.wget_buf, "REST %"OFF_FMT"u", G.beg_range);
		if (ftpcmd(G.wget_buf, NULL, sfp) == 350)
			G.content_len -= G.beg_range;
		else
			reset_beg_range_to_zero();
	}

//TODO: needs ftp-escaping 0xff and '\n' bytes here.
//Or disallow '\n' altogether via sanitize_string() in parse_url().
//But 0xff's are possible in valid utf8 filenames.
	if (ftpcmd("RETR ", target->path, sfp) > 150)
		bb_error_msg_and_die("bad response to %s: %s", "RETR", G.wget_buf);

	return sfp;
}

static void NOINLINE retrieve_file_data(FILE *dfp)
{
#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
# if ENABLE_FEATURE_WGET_TIMEOUT
	unsigned second_cnt = G.timeout_seconds;
# endif
	struct pollfd polldata;

	polldata.fd = fileno(dfp);
	polldata.events = POLLIN | POLLPRI;
#endif
	progress_meter(PROGRESS_START);

	if (G.chunked)
		goto get_clen;

	/* Loops only if chunked */
	while (1) {

#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
		/* Must use nonblocking I/O, otherwise fread will loop
		 * and *block* until it reads full buffer,
		 * which messes up progress bar and/or timeout logic.
		 * Because of nonblocking I/O, we need to dance
		 * very carefully around EAGAIN. See explanation at
		 * clearerr() calls.
		 */
		ndelay_on(polldata.fd);
#endif
		while (1) {
			int n;
			unsigned rdsz;

#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
			/* fread internally uses read loop, which in our case
			 * is usually exited when we get EAGAIN.
			 * In this case, libc sets error marker on the stream.
			 * Need to clear it before next fread to avoid possible
			 * rare false positive ferror below. Rare because usually
			 * fread gets more than zero bytes, and we don't fall
			 * into if (n <= 0) ...
			 */
			clearerr(dfp);
#endif
			errno = 0;
			rdsz = sizeof(G.wget_buf);
			if (G.got_clen) {
				if (G.content_len < (off_t)sizeof(G.wget_buf)) {
					if ((int)G.content_len <= 0)
						break;
					rdsz = (unsigned)G.content_len;
				}
			}
			n = fread(G.wget_buf, 1, rdsz, dfp);

			if (n > 0) {
				xwrite(G.output_fd, G.wget_buf, n);
#if ENABLE_FEATURE_WGET_STATUSBAR
				G.transferred += n;
#endif
				if (G.got_clen) {
					G.content_len -= n;
					if (G.content_len == 0)
						break;
				}
#if ENABLE_FEATURE_WGET_TIMEOUT
				second_cnt = G.timeout_seconds;
#endif
				goto bump;
			}

			/* n <= 0.
			 * man fread:
			 * If error occurs, or EOF is reached, the return value
			 * is a short item count (or zero).
			 * fread does not distinguish between EOF and error.
			 */
			if (errno != EAGAIN) {
				if (ferror(dfp)) {
					progress_meter(PROGRESS_END);
					bb_perror_msg_and_die(bb_msg_read_error);
				}
				break; /* EOF, not error */
			}

#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
			/* It was EAGAIN. There is no data. Wait up to one second
			 * then abort if timed out, or update the bar and try reading again.
			 */
			if (safe_poll(&polldata, 1, 1000) == 0) {
# if ENABLE_FEATURE_WGET_TIMEOUT
				if (second_cnt != 0 && --second_cnt == 0) {
					progress_meter(PROGRESS_END);
					bb_error_msg_and_die("download timed out");
				}
# endif
				/* We used to loop back to poll here,
				 * but there is no great harm in letting fread
				 * to try reading anyway.
				 */
			}
#endif
 bump:
			/* Need to do it _every_ second for "stalled" indicator
			 * to be shown properly.
			 */
			progress_meter(PROGRESS_BUMP);
		} /* while (reading data) */

#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
		clearerr(dfp);
		ndelay_off(polldata.fd); /* else fgets can get very unhappy */
#endif
		if (!G.chunked)
			break;

		/* Each chunk ends with "\r\n" - eat it */
		fgets_trim_sanitize(dfp, NULL);
 get_clen:
		/* chunk size format is "HEXNUM[;name[=val]]\r\n" */
		fgets_trim_sanitize(dfp, NULL);
		errno = 0;
		G.content_len = STRTOOFF(G.wget_buf, NULL, 16);
		/*
		 * Had a bug with inputs like "ffffffff0001f400"
		 * smashing the heap later. Ensure >= 0.
		 */
		if (G.content_len < 0 || errno)
			bb_error_msg_and_die("bad chunk length '%s'", G.wget_buf);
		if (G.content_len == 0)
			break; /* all done! */
		G.got_clen = 1;
		/*
		 * Note that fgets may result in some data being buffered in dfp.
		 * We loop back to fread, which will retrieve this data.
		 * Also note that code has to be arranged so that fread
		 * is done _before_ one-second poll wait - poll doesn't know
		 * about stdio buffering and can result in spurious one second waits!
		 */
	}

	/* If -c failed, we restart from the beginning,
	 * but we do not truncate file then, we do it only now, at the end.
	 * This lets user to ^C if his 99% complete 10 GB file download
	 * failed to restart *without* losing the almost complete file.
	 */
	{
		off_t pos = lseek(G.output_fd, 0, SEEK_CUR);
		if (pos != (off_t)-1)
			ftruncate(G.output_fd, pos);
	}

	/* Draw full bar and free its resources */
	G.chunked = 0;  /* makes it show 100% even for chunked download */
	G.got_clen = 1; /* makes it show 100% even for download of (formerly) unknown size */
	progress_meter(PROGRESS_END);
}

static void download_one_url(const char *url)
{
	bool use_proxy;                 /* Use proxies if env vars are set  */
	int redir_limit;
	len_and_sockaddr *lsa;
	FILE *sfp;                      /* socket to web/ftp server         */
	FILE *dfp;                      /* socket to ftp server (data)      */
	char *fname_out_alloc;
	char *redirected_path = NULL;
	struct host_info server;
	struct host_info target;

	server.allocated = NULL;
	target.allocated = NULL;
	server.user = NULL;
	target.user = NULL;

	parse_url(url, &target);

	/* Use the proxy if necessary */
	use_proxy = (strcmp(G.proxy_flag, "off") != 0);
	if (use_proxy) {
		char *proxy = getenv(target.protocol[0] == 'f' ? "ftp_proxy" : "http_proxy");
//FIXME: what if protocol is https? Ok to use http_proxy?
		use_proxy = (proxy && proxy[0]);
		if (use_proxy)
			parse_url(proxy, &server);
	}
	if (!use_proxy) {
		server.protocol = target.protocol;
		server.port = target.port;
		if (ENABLE_FEATURE_IPV6) {
			//free(server.allocated); - can't be non-NULL
			server.host = server.allocated = xstrdup(target.host);
		} else {
			server.host = target.host;
		}
	}

	if (ENABLE_FEATURE_IPV6)
		strip_ipv6_scope_id(target.host);

	/* If there was no -O FILE, guess output filename */
	fname_out_alloc = NULL;
	if (!(option_mask32 & WGET_OPT_OUTNAME)) {
		G.fname_out = bb_get_last_path_component_nostrip(target.path);
		/* handle "wget http://kernel.org//" */
		if (G.fname_out[0] == '/' || !G.fname_out[0])
			G.fname_out = (char*)"index.html";
		/* -P DIR is considered only if there was no -O FILE */
		if (G.dir_prefix)
			G.fname_out = fname_out_alloc = concat_path_file(G.dir_prefix, G.fname_out);
		else {
			/* redirects may free target.path later, need to make a copy */
			G.fname_out = fname_out_alloc = xstrdup(G.fname_out);
		}
	}
#if ENABLE_FEATURE_WGET_STATUSBAR
	G.curfile = bb_get_last_path_component_nostrip(G.fname_out);
#endif

	/* Determine where to start transfer */
	G.beg_range = 0;
	if (option_mask32 & WGET_OPT_CONTINUE) {
		G.output_fd = open(G.fname_out, O_WRONLY);
		if (G.output_fd >= 0) {
			G.beg_range = xlseek(G.output_fd, 0, SEEK_END);
		}
		/* File doesn't exist. We do not create file here yet.
		 * We are not sure it exists on remote side */
	}

	redir_limit = 5;
 resolve_lsa:
	lsa = xhost2sockaddr(server.host, server.port);
	if (!(option_mask32 & WGET_OPT_QUIET)) {
		char *s = xmalloc_sockaddr2dotted(&lsa->u.sa);
		fprintf(stderr, "Connecting to %s (%s)\n", server.host, s);
		free(s);
	}
 establish_session:
	/*G.content_len = 0; - redundant, got_clen = 0 is enough */
	G.got_clen = 0;
	G.chunked = 0;
	if (use_proxy || target.protocol[0] != 'f' /*not ftp[s]*/) {
		/*
		 *  HTTP session
		 */
		char *str;
		int status;

		/* Open socket to http(s) server */
#if ENABLE_FEATURE_WGET_OPENSSL
		/* openssl (and maybe internal TLS) support is configured */
		if (server.protocol == P_HTTPS) {
			/* openssl-based helper
			 * Inconvenient API since we can't give it an open fd
			 */
			int fd = spawn_https_helper_openssl(server.host, server.port);
# if ENABLE_FEATURE_WGET_HTTPS
			if (fd < 0) { /* no openssl? try internal */
				sfp = open_socket(lsa);
				spawn_ssl_client(server.host, fileno(sfp), /*flags*/ 0);
				goto socket_opened;
			}
# else
			/* We don't check for exec("openssl") failure in this case */
# endif
			sfp = fdopen(fd, "r+");
			if (!sfp)
				bb_die_memory_exhausted();
			goto socket_opened;
		}
		sfp = open_socket(lsa);
 socket_opened:
#elif ENABLE_FEATURE_WGET_HTTPS
		/* Only internal TLS support is configured */
		sfp = open_socket(lsa);
		if (server.protocol == P_HTTPS)
			spawn_ssl_client(server.host, fileno(sfp), /*flags*/ 0);
#else
		/* ssl (https) support is not configured */
		sfp = open_socket(lsa);
#endif
		/* Send HTTP request */
		if (use_proxy) {
			SENDFMT(sfp, "GET %s://%s/%s HTTP/1.1\r\n",
				target.protocol, target.host,
				target.path);
		} else {
			SENDFMT(sfp, "%s /%s HTTP/1.1\r\n",
				(option_mask32 & WGET_OPT_POST_DATA) ? "POST" : "GET",
				target.path);
		}
		if (!USR_HEADER_HOST)
			SENDFMT(sfp, "Host: %s\r\n", target.host);
		if (!USR_HEADER_USER_AGENT)
			SENDFMT(sfp, "User-Agent: %s\r\n", G.user_agent);

		/* Ask server to close the connection as soon as we are done
		 * (IOW: we do not intend to send more requests)
		 */
		SENDFMT(sfp, "Connection: close\r\n");

#if ENABLE_FEATURE_WGET_AUTHENTICATION
		if (target.user && !USR_HEADER_AUTH) {
			SENDFMT(sfp, "Proxy-Authorization: Basic %s\r\n"+6,
				base64enc(target.user));
		}
		if (use_proxy && server.user && !USR_HEADER_PROXY_AUTH) {
			SENDFMT(sfp, "Proxy-Authorization: Basic %s\r\n",
				base64enc(server.user));
		}
#endif

		if (G.beg_range != 0 && !USR_HEADER_RANGE)
			SENDFMT(sfp, "Range: bytes=%"OFF_FMT"u-\r\n", G.beg_range);

#if ENABLE_FEATURE_WGET_LONG_OPTIONS
		if (G.extra_headers) {
			log_io(G.extra_headers);
			fputs(G.extra_headers, sfp);
		}

		if (option_mask32 & WGET_OPT_POST_DATA) {
			SENDFMT(sfp,
				"Content-Type: application/x-www-form-urlencoded\r\n"
				"Content-Length: %u\r\n"
				"\r\n"
				"%s",
				(int) strlen(G.post_data), G.post_data
			);
		} else
#endif
		{
			SENDFMT(sfp, "\r\n");
		}

		fflush(sfp);

/* Tried doing this unconditionally.
 * Cloudflare and nginx/1.11.5 are shocked to see SHUT_WR on non-HTTPS.
 */
#if SSL_SUPPORTED
		if (target.protocol == P_HTTPS) {
			/* If we use SSL helper, keeping our end of the socket open for writing
			 * makes our end (i.e. the same fd!) readable (EAGAIN instead of EOF)
			 * even after child closes its copy of the fd.
			 * This helps:
			 */
			shutdown(fileno(sfp), SHUT_WR);
		}
#endif

		/*
		 * Retrieve HTTP response line and check for "200" status code.
		 */
 read_response:
		fgets_trim_sanitize(sfp, "  %s\n");

		str = G.wget_buf;
		str = skip_non_whitespace(str);
		str = skip_whitespace(str);
		// FIXME: no error check
		// xatou wouldn't work: "200 OK"
		status = atoi(str);
		switch (status) {
		case 0:
		case 100:
			while (get_sanitized_hdr(sfp) != NULL)
				/* eat all remaining headers */;
			goto read_response;

		/* Success responses */
		case 200:
			/* fall through */
		case 201: /* 201 Created */
/* "The request has been fulfilled and resulted in a new resource being created" */
			/* Standard wget is reported to treat this as success */
			/* fall through */
		case 202: /* 202 Accepted */
/* "The request has been accepted for processing, but the processing has not been completed" */
			/* Treat as success: fall through */
		case 203: /* 203 Non-Authoritative Information */
/* "Use of this response code is not required and is only appropriate when the response would otherwise be 200 (OK)" */
			/* fall through */
		case 204: /* 204 No Content */
/*
Response 204 doesn't say "null file", it says "metadata
has changed but data didn't":

"10.2.5 204 No Content
The server has fulfilled the request but does not need to return
an entity-body, and might want to return updated metainformation.
The response MAY include new or updated metainformation in the form
of entity-headers, which if present SHOULD be associated with
the requested variant.

If the client is a user agent, it SHOULD NOT change its document
view from that which caused the request to be sent. This response
is primarily intended to allow input for actions to take place
without causing a change to the user agent's active document view,
although any new or updated metainformation SHOULD be applied
to the document currently in the user agent's active view.

The 204 response MUST NOT include a message-body, and thus
is always terminated by the first empty line after the header fields."

However, in real world it was observed that some web servers
(e.g. Boa/0.94.14rc21) simply use code 204 when file size is zero.
*/
			if (G.beg_range != 0) {
				/* "Range:..." was not honored by the server.
				 * Restart download from the beginning.
				 */
				reset_beg_range_to_zero();
			}
			break;
		/* 205 Reset Content ?? what to do on this ?? 	*/

		case 300:  /* redirection */
		case 301:
		case 302:
		case 303:
			break;

		case 206: /* Partial Content */
			if (G.beg_range != 0)
				/* "Range:..." worked. Good. */
				break;
			/* Partial Content even though we did not ask for it??? */
			/* fall through */
		default:
			bb_error_msg_and_die("server returned error: %s", G.wget_buf);
		}

		/*
		 * Retrieve HTTP headers.
		 */
		while ((str = get_sanitized_hdr(sfp)) != NULL) {
			static const char keywords[] ALIGN1 =
				"content-length\0""transfer-encoding\0""location\0";
			enum {
				KEY_content_length = 1, KEY_transfer_encoding, KEY_location
			};
			smalluint key;

			/* get_sanitized_hdr converted "FOO:" string to lowercase */

			/* strip trailing whitespace */
			char *s = strchrnul(str, '\0') - 1;
			while (s >= str && (*s == ' ' || *s == '\t')) {
				*s = '\0';
				s--;
			}
			key = index_in_strings(keywords, G.wget_buf) + 1;
			if (key == KEY_content_length) {
				G.content_len = BB_STRTOOFF(str, NULL, 10);
				if (G.content_len < 0 || errno) {
					bb_error_msg_and_die("content-length %s is garbage", str);
				}
				G.got_clen = 1;
				continue;
			}
			if (key == KEY_transfer_encoding) {
				if (strcmp(str_tolower(str), "chunked") != 0)
					bb_error_msg_and_die("transfer encoding '%s' is not supported", str);
				G.chunked = 1;
			}
			if (key == KEY_location && status >= 300) {
				if (--redir_limit == 0)
					bb_error_msg_and_die("too many redirections");
				fclose(sfp);
				if (str[0] == '/') {
					free(redirected_path);
					target.path = redirected_path = xstrdup(str + 1);
					/* lsa stays the same: it's on the same server */
				} else {
					parse_url(str, &target);
					if (!use_proxy) {
						/* server.user remains untouched */
						free(server.allocated);
						server.allocated = NULL;
						server.protocol = target.protocol;
						server.host = target.host;
						/* strip_ipv6_scope_id(target.host); - no! */
						/* we assume remote never gives us IPv6 addr with scope id */
						server.port = target.port;
						free(lsa);
						goto resolve_lsa;
					} /* else: lsa stays the same: we use proxy */
				}
				goto establish_session;
			}
		}
//		if (status >= 300)
//			bb_error_msg_and_die("bad redirection (no Location: header from server)");

		/* For HTTP, data is pumped over the same connection */
		dfp = sfp;
	} else {
		/*
		 *  FTP session
		 */
		sfp = prepare_ftp_session(&dfp, &target, lsa);
	}

	free(lsa);

	if (!(option_mask32 & WGET_OPT_SPIDER)) {
		if (G.output_fd < 0)
			G.output_fd = xopen(G.fname_out, G.o_flags);
		retrieve_file_data(dfp);
		if (!(option_mask32 & WGET_OPT_OUTNAME)) {
			xclose(G.output_fd);
			G.output_fd = -1;
		}
	}

	if (dfp != sfp) {
		/* It's ftp. Close data connection properly */
		fclose(dfp);
		if (ftpcmd(NULL, NULL, sfp) != 226)
			bb_error_msg_and_die("ftp error: %s", G.wget_buf);
		/* ftpcmd("QUIT", NULL, sfp); - why bother? */
	}
	fclose(sfp);

	free(server.allocated);
	free(target.allocated);
	free(server.user);
	free(target.user);
	free(fname_out_alloc);
	free(redirected_path);
}

int wget_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int wget_main(int argc UNUSED_PARAM, char **argv)
{
#if ENABLE_FEATURE_WGET_LONG_OPTIONS
	static const char wget_longopts[] ALIGN1 =
		/* name, has_arg, val */
		"continue\0"         No_argument       "c"
		"quiet\0"            No_argument       "q"
		"server-response\0"  No_argument       "S"
		"output-document\0"  Required_argument "O"
		"directory-prefix\0" Required_argument "P"
		"proxy\0"            Required_argument "Y"
		"user-agent\0"       Required_argument "U"
IF_FEATURE_WGET_TIMEOUT(
		"timeout\0"          Required_argument "T")
		/* Ignored: */
IF_DESKTOP(	"tries\0"            Required_argument "t")
		"header\0"           Required_argument "\xff"
		"post-data\0"        Required_argument "\xfe"
		"spider\0"           No_argument       "\xfd"
		"no-check-certificate\0" No_argument   "\xfc"
		/* Ignored (we always use PASV): */
IF_DESKTOP(	"passive-ftp\0"      No_argument       "\xf0")
		/* Ignored (we don't support caching) */
IF_DESKTOP(	"no-cache\0"         No_argument       "\xf0")
IF_DESKTOP(	"no-verbose\0"       No_argument       "\xf0")
IF_DESKTOP(	"no-clobber\0"       No_argument       "\xf0")
IF_DESKTOP(	"no-host-directories\0" No_argument    "\xf0")
IF_DESKTOP(	"no-parent\0"        No_argument       "\xf0")
		;
# define GETOPT32 getopt32long
# define LONGOPTS ,wget_longopts
#else
# define GETOPT32 getopt32
# define LONGOPTS
#endif

#if ENABLE_FEATURE_WGET_LONG_OPTIONS
	llist_t *headers_llist = NULL;
#endif

	INIT_G();

#if ENABLE_FEATURE_WGET_TIMEOUT
	G.timeout_seconds = 900;
	signal(SIGALRM, alarm_handler);
#endif
	G.proxy_flag = "on";   /* use proxies if env vars are set */
	G.user_agent = "Wget"; /* "User-Agent" header field */

#if ENABLE_FEATURE_WGET_LONG_OPTIONS
#endif
	GETOPT32(argv, "^"
		"cqSO:P:Y:U:T:+"
		/*ignored:*/ "t:"
		/*ignored:*/ "n::"
		/* wget has exactly four -n<letter> opts, all of which we can ignore:
		 * -nv --no-verbose: be moderately quiet (-q is full quiet)
		 * -nc --no-clobber: abort if exists, neither download to FILE.n nor overwrite FILE
		 * -nH --no-host-directories: wget -r http://host/ won't create host/
		 * -np --no-parent
		 * "n::" above says that we accept -n[ARG].
		 * Specifying "n:" would be a bug: "-n ARG" would eat ARG!
		 */
		"\0"
		"-1" /* at least one URL */
		IF_FEATURE_WGET_LONG_OPTIONS(":\xff::") /* --header is a list */
		LONGOPTS
		, &G.fname_out, &G.dir_prefix,
		&G.proxy_flag, &G.user_agent,
		IF_FEATURE_WGET_TIMEOUT(&G.timeout_seconds) IF_NOT_FEATURE_WGET_TIMEOUT(NULL),
		NULL, /* -t RETRIES */
		NULL  /* -n[ARG] */
		IF_FEATURE_WGET_LONG_OPTIONS(, &headers_llist)
		IF_FEATURE_WGET_LONG_OPTIONS(, &G.post_data)
	);
#if 0 /* option bits debug */
	if (option_mask32 & WGET_OPT_RETRIES) bb_error_msg("-t NUM");
	if (option_mask32 & WGET_OPT_nsomething) bb_error_msg("-nsomething");
	if (option_mask32 & WGET_OPT_HEADER) bb_error_msg("--header");
	if (option_mask32 & WGET_OPT_POST_DATA) bb_error_msg("--post-data");
	if (option_mask32 & WGET_OPT_SPIDER) bb_error_msg("--spider");
	if (option_mask32 & WGET_OPT_NO_CHECK_CERT) bb_error_msg("--no-check-certificate");
	exit(0);
#endif
	argv += optind;

#if ENABLE_FEATURE_WGET_LONG_OPTIONS
	if (headers_llist) {
		int size = 0;
		char *hdr;
		llist_t *ll = headers_llist;
		while (ll) {
			size += strlen(ll->data) + 2;
			ll = ll->link;
		}
		G.extra_headers = hdr = xmalloc(size + 1);
		while (headers_llist) {
			int bit;
			const char *words;

			size = sprintf(hdr, "%s\r\n",
					(char*)llist_pop(&headers_llist));
			/* a bit like index_in_substrings but don't match full key */
			bit = 1;
			words = wget_user_headers;
			while (*words) {
				if (strstr(hdr, words) == hdr) {
					G.user_headers |= bit;
					break;
				}
				bit <<= 1;
				words += strlen(words) + 1;
			}
			hdr += size;
		}
	}
#endif

	G.output_fd = -1;
	G.o_flags = O_WRONLY | O_CREAT | O_TRUNC | O_EXCL;
	if (G.fname_out) { /* -O FILE ? */
		if (LONE_DASH(G.fname_out)) { /* -O - ? */
			G.output_fd = 1;
			option_mask32 &= ~WGET_OPT_CONTINUE;
		}
		/* compat with wget: -O FILE can overwrite */
		G.o_flags = O_WRONLY | O_CREAT | O_TRUNC;
	}

	while (*argv)
		download_one_url(*argv++);

	if (G.output_fd >= 0)
		xclose(G.output_fd);

#if ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_WGET_LONG_OPTIONS
	free(G.extra_headers);
#endif
	FINI_G();

	return EXIT_SUCCESS;
}