summaryrefslogtreecommitdiff
path: root/networking/wget.c
blob: 7ca947aec1a4c5609c5f5b7f3fc91479038d8daf (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
/* 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.
 */

//usage:#define wget_trivial_usage
//usage:	IF_FEATURE_WGET_LONG_OPTIONS(
//usage:       "[-c|--continue] [-s|--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]" */
//usage:       "	[-U|--user-agent AGENT]" IF_FEATURE_WGET_TIMEOUT(" [-T SEC]") " URL..."
//usage:	)
//usage:	IF_NOT_FEATURE_WGET_LONG_OPTIONS(
//usage:       "[-csq] [-O FILE] [-Y on/off] [-P DIR] [-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:     "\n	-s	Spider mode - only check file existence"
//usage:     "\n	-c	Continue retrieval of aborted transfer"
//usage:     "\n	-q	Quiet"
//usage:     "\n	-P DIR	Save to DIR (default .)"
//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	Use proxy ('on' or 'off')"

#include "libbb.h"

#if 0
# define log_io(...) bb_error_msg(__VA_ARGS__)
#else
# define log_io(...) ((void)0)
#endif


struct host_info {
	char *allocated;
	const char *path;
	char       *user;
	char       *host;
	int         port;
	smallint    is_ftp;
};


/* 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;
#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 connecting;
#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_SPIDER     = (1 << 1),
	WGET_OPT_QUIET      = (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_PASSIVE    = (1 << 9),
	WGET_OPT_HEADER     = (1 << 10) * ENABLE_FEATURE_WGET_LONG_OPTIONS,
	WGET_OPT_POST_DATA  = (1 << 11) * 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

static char* sanitize_string(char *s)
{
	unsigned char *p = (void *) s;
	while (*p >= ' ')
		p++;
	*p = '\0';
	return s;
}

#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.connecting)
		bb_error_msg_and_die("download timed out");
}
#endif

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

	IF_FEATURE_WGET_TIMEOUT(alarm(G.timeout_seconds); G.connecting = 1;)
	fd = xconnect_stream(lsa);
	IF_FEATURE_WGET_TIMEOUT(G.connecting = 0;)

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

	return fp;
}

/* Returns '\n' if it was seen, else '\0'. Trims at first '\r' or '\n' */
/* FIXME: does not respect FEATURE_WGET_TIMEOUT and -T N: */
static char fgets_and_trim(FILE *fp)
{
	char c;
	char *buf_ptr;

	if (fgets(G.wget_buf, sizeof(G.wget_buf) - 1, fp) == NULL)
		bb_perror_msg_and_die("error getting response");

	buf_ptr = strchrnul(G.wget_buf, '\n');
	c = *buf_ptr;
	*buf_ptr = '\0';
	buf_ptr = strchrnul(G.wget_buf, '\r');
	*buf_ptr = '\0';

	log_io("< %s", 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);
		fflush(fp);
		log_io("> %s%s", s1, s2);
	}

	do {
		fgets_and_trim(fp);
	} 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);

	if (strncmp(url, "ftp://", 6) == 0) {
		h->port = bb_lookup_port("ftp", "tcp", 21);
		h->host = url + 6;
		h->is_ftp = 1;
	} else
	if (strncmp(url, "http://", 7) == 0) {
		h->host = url + 7;
 http:
		h->port = bb_lookup_port("http", "tcp", 80);
		h->is_ftp = 0;
	} else
	if (!strstr(url, "//")) {
		// GNU wget is user-friendly and falls back to http://
		h->host = url;
		goto http;
	} else
		bb_error_msg_and_die("not an http or ftp url: %s", sanitize_string(url));

	// 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 { // '#' or '?'
		// http://busybox.net?login=john@doe is a valid URL
		// memmove converts to:
		// http:/busybox.nett?login=john@doe...
		memmove(h->host - 1, h->host, sp - h->host);
		h->host--;
		sp[-1] = '\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 *gethdr(FILE *fp)
{
	char *s, *hdrval;
	int c;

	/* retrieve header line */
	c = fgets_and_trim(fp);

	/* 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", sanitize_string(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); */
}

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

	if (!target->user)
		target->user = xstrdup("anonymous:busybox@");

	sfp = open_socket(lsa);
	if (ftpcmd(NULL, NULL, sfp) != 220)
		bb_error_msg_and_die("%s", sanitize_string(G.wget_buf + 4));

	/*
	 * Splitting username:password pair,
	 * trying to log in
	 */
	str = strchr(target->user, ':');
	if (str)
		*str++ = '\0';
	switch (ftpcmd("USER ", target->user, sfp)) {
	case 230:
		break;
	case 331:
		if (ftpcmd("PASS ", str, sfp) == 230)
			break;
		/* fall through (failed login) */
	default:
		bb_error_msg_and_die("ftp login: %s", sanitize_string(G.wget_buf + 4));
	}

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

	/*
	 * Querying 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("SIZE value is garbage");
		}
		G.got_clen = 1;
	}

	/*
	 * Entering passive mode
	 */
	if (ftpcmd("PASV", NULL, sfp) != 227) {
 pasv_error:
		bb_error_msg_and_die("bad response to %s: %s", "PASV", sanitize_string(G.wget_buf));
	}
	// Response is "227 garbageN1,N2,N3,N4,P1,P2[)garbage]
	// Server's IP is N1.N2.N3.N4 (we ignore it)
	// Server's port for data connection is P1*256+P2
	str = strrchr(G.wget_buf, ')');
	if (str) str[0] = '\0';
	str = strrchr(G.wget_buf, ',');
	if (!str) goto pasv_error;
	port = xatou_range(str+1, 0, 255);
	*str = '\0';
	str = strrchr(G.wget_buf, ',');
	if (!str) goto pasv_error;
	port += xatou_range(str+1, 0, 255) * 256;
	set_nport(&lsa->u.sa, htons(port));

	*dfpp = open_socket(lsa);

	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();
	}

	if (ftpcmd("RETR ", target->path, sfp) > 150)
		bb_error_msg_and_die("bad response to %s: %s", "RETR", sanitize_string(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
				continue;
			}

			/* 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.
				 */
			}
			/* Need to do it _every_ second for "stalled" indicator
			 * to be shown properly.
			 */
			progress_meter(PROGRESS_BUMP);
#endif
		} /* 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;

		fgets_and_trim(dfp); /* Eat empty line */
 get_clen:
		fgets_and_trim(dfp);
		G.content_len = STRTOOFF(G.wget_buf, NULL, 16);
		/* FIXME: error check? */
		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 *proxy = NULL;
	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) {
		proxy = getenv(target.is_ftp ? "ftp_proxy" : "http_proxy");
		use_proxy = (proxy && proxy[0]);
		if (use_proxy)
			parse_url(proxy, &server);
	}
	if (!use_proxy) {
		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.is_ftp) {
		/*
		 *  HTTP session
		 */
		char *str;
		int status;


		/* Open socket to http server */
		sfp = open_socket(lsa);

		/* Send HTTP request */
		if (use_proxy) {
			fprintf(sfp, "GET %stp://%s/%s HTTP/1.1\r\n",
				target.is_ftp ? "f" : "ht", target.host,
				target.path);
		} else {
			if (option_mask32 & WGET_OPT_POST_DATA)
				fprintf(sfp, "POST /%s HTTP/1.1\r\n", target.path);
			else
				fprintf(sfp, "GET /%s HTTP/1.1\r\n", target.path);
		}

		fprintf(sfp, "Host: %s\r\nUser-Agent: %s\r\n",
			target.host, G.user_agent);

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

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

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

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

		if (option_mask32 & WGET_OPT_POST_DATA) {
			fprintf(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
		{
			fprintf(sfp, "\r\n");
		}

		fflush(sfp);

		/*
		 * Retrieve HTTP response line and check for "200" status code.
		 */
 read_response:
		fgets_and_trim(sfp);

		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 (gethdr(sfp) != NULL)
				/* eat all remaining headers */;
			goto read_response;
		case 200:
/*
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.
*/
		case 204:
			if (G.beg_range != 0) {
				/* "Range:..." was not honored by the server.
				 * Restart download from the beginning.
				 */
				reset_beg_range_to_zero();
			}
			break;
		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", sanitize_string(G.wget_buf));
		}

		/*
		 * Retrieve HTTP headers.
		 */
		while ((str = gethdr(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;

			/* gethdr 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", sanitize_string(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", sanitize_string(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.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", sanitize_string(G.wget_buf + 4));
		/* 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"
//FIXME: -s isn't --spider, it's --save-headers!
		"spider\0"           No_argument       "s"
		"quiet\0"            No_argument       "q"
		"output-document\0"  Required_argument "O"
		"directory-prefix\0" Required_argument "P"
		"proxy\0"            Required_argument "Y"
		"user-agent\0"       Required_argument "U"
#if ENABLE_FEATURE_WGET_TIMEOUT
		"timeout\0"          Required_argument "T"
#endif
		/* Ignored: */
		// "tries\0"            Required_argument "t"
		/* Ignored (we always use PASV): */
		"passive-ftp\0"      No_argument       "\xff"
		"header\0"           Required_argument "\xfe"
		"post-data\0"        Required_argument "\xfd"
		/* Ignored (we don't do ssl) */
		"no-check-certificate\0" No_argument   "\xfc"
		/* Ignored (we don't support caching) */
		"no-cache\0"         No_argument       "\xfb"
		;
#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
	applet_long_options = wget_longopts;
#endif
	opt_complementary = "-1" IF_FEATURE_WGET_TIMEOUT(":T+") IF_FEATURE_WGET_LONG_OPTIONS(":\xfe::");
	getopt32(argv, "csqO:P:Y:U:T:" /*ignored:*/ "t:",
		&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 */
		IF_FEATURE_WGET_LONG_OPTIONS(, &headers_llist)
		IF_FEATURE_WGET_LONG_OPTIONS(, &G.post_data)
	);
	argv += optind;

#if ENABLE_FEATURE_WGET_LONG_OPTIONS
	if (headers_llist) {
		int size = 1;
		char *cp;
		llist_t *ll = headers_llist;
		while (ll) {
			size += strlen(ll->data) + 2;
			ll = ll->link;
		}
		G.extra_headers = cp = xmalloc(size);
		while (headers_llist) {
			cp += sprintf(cp, "%s\r\n", (char*)llist_pop(&headers_llist));
		}
	}
#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;
}