summaryrefslogtreecommitdiff
path: root/connect.c
blob: 24281b608284ee74b262237c467ff054874d8a8e (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
#include "git-compat-util.h"
#include "cache.h"
#include "config.h"
#include "pkt-line.h"
#include "quote.h"
#include "refs.h"
#include "run-command.h"
#include "remote.h"
#include "connect.h"
#include "url.h"
#include "string-list.h"
#include "sha1-array.h"
#include "transport.h"
#include "strbuf.h"
#include "version.h"
#include "protocol.h"
#include "alias.h"
 
static char *server_capabilities_v1;
static struct argv_array server_capabilities_v2 = ARGV_ARRAY_INIT;
static const char *parse_feature_value(const char *, const char *, int *);
 
static int check_ref(const char *name, unsigned int flags)
{
	if (!flags)
		return 1;
 
	if (!skip_prefix(name, "refs/", &name))
		return 0;
 
	/* REF_NORMAL means that we don't want the magic fake tag refs */
	if ((flags & REF_NORMAL) && check_refname_format(name, 0))
		return 0;
 
	/* REF_HEADS means that we want regular branch heads */
	if ((flags & REF_HEADS) && starts_with(name, "heads/"))
		return 1;
 
	/* REF_TAGS means that we want tags */
	if ((flags & REF_TAGS) && starts_with(name, "tags/"))
		return 1;
 
	/* All type bits clear means that we are ok with anything */
	return !(flags & ~REF_NORMAL);
}
 
int check_ref_type(const struct ref *ref, int flags)
{
	return check_ref(ref->name, flags);
}
 
static NORETURN void die_initial_contact(int unexpected)
{
	/*
	 * A hang-up after seeing some response from the other end
	 * means that it is unexpected, as we know the other end is
	 * willing to talk to us.  A hang-up before seeing any
	 * response does not necessarily mean an ACL problem, though.
	 */
	if (unexpected)
		die(_("the remote end hung up upon initial contact"));
	else
		die(_("Could not read from remote repository.\n\n"
		      "Please make sure you have the correct access rights\n"
		      "and the repository exists."));
}
 
/* Checks if the server supports the capability 'c' */
int server_supports_v2(const char *c, int die_on_error)
{
	int i;
 
	for (i = 0; i < server_capabilities_v2.argc; i++) {
		const char *out;
		if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
		    (!*out || *out == '='))
			return 1;
	}
 
	if (die_on_error)
		die(_("server doesn't support '%s'"), c);
 
	return 0;
}
 
int server_supports_feature(const char *c, const char *feature,
			    int die_on_error)
{
	int i;
 
	for (i = 0; i < server_capabilities_v2.argc; i++) {
		const char *out;
		if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
		    (!*out || *(out++) == '=')) {
			if (parse_feature_request(out, feature))
				return 1;
			else
				break;
		}
	}
 
	if (die_on_error)
		die(_("server doesn't support feature '%s'"), feature);
 
	return 0;
}
 
static void process_capabilities_v2(struct packet_reader *reader)
{
	while (packet_reader_read(reader) == PACKET_READ_NORMAL)
		argv_array_push(&server_capabilities_v2, reader->line);
 
	if (reader->status != PACKET_READ_FLUSH)
		die(_("expected flush after capabilities"));
}
 
enum protocol_version discover_version(struct packet_reader *reader)
{
	enum protocol_version version = protocol_unknown_version;
 
	/*
	 * Peek the first line of the server's response to
	 * determine the protocol version the server is speaking.
	 */
	switch (packet_reader_peek(reader)) {
	case PACKET_READ_EOF:
		die_initial_contact(0);
	case PACKET_READ_FLUSH:
	case PACKET_READ_DELIM:
		version = protocol_v0;
		break;
	case PACKET_READ_NORMAL:
		version = determine_protocol_version_client(reader->line);
		break;
	}
 
	switch (version) {
	case protocol_v2:
		process_capabilities_v2(reader);
		break;
	case protocol_v1:
		/* Read the peeked version line */
		packet_reader_read(reader);
		break;
	case protocol_v0:
		break;
	case protocol_unknown_version:
		BUG("unknown protocol version");
	}
 
	return version;
}
 
static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
{
	char *sym, *target;
	struct string_list_item *item;
 
	if (!len)
		return; /* just "symref" */
	/* e.g. "symref=HEAD:refs/heads/master" */
	sym = xmemdupz(val, len);
	target = strchr(sym, ':');
	if (!target)
		/* just "symref=something" */
		goto reject;
	*(target++) = '\0';
	if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
	    check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
		/* "symref=bogus:pair */
		goto reject;
	item = string_list_append_nodup(symref, sym);
	item->util = target;
	return;
reject:
	free(sym);
	return;
}
 
static void annotate_refs_with_symref_info(struct ref *ref)
{
	struct string_list symref = STRING_LIST_INIT_DUP;
	const char *feature_list = server_capabilities_v1;
 
	while (feature_list) {
		int len;
		const char *val;
 
		val = parse_feature_value(feature_list, "symref", &len);
		if (!val)
			break;
		parse_one_symref_info(&symref, val, len);
		feature_list = val + 1;
	}
	string_list_sort(&symref);
 
	for (; ref; ref = ref->next) {
		struct string_list_item *item;
		item = string_list_lookup(&symref, ref->name);
		if (!item)
			continue;
		ref->symref = xstrdup((char *)item->util);
	}
	string_list_clear(&symref, 0);
}
 
static void process_capabilities(const char *line, int *len)
{
	int nul_location = strlen(line);
	if (nul_location == *len)
		return;
	server_capabilities_v1 = xstrdup(line + nul_location + 1);
	*len = nul_location;
}
 
static int process_dummy_ref(const char *line)
{
	struct object_id oid;
	const char *name;
 
	if (parse_oid_hex(line, &oid, &name))
		return 0;
	if (*name != ' ')
		return 0;
	name++;
 
	return oideq(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
}
 
static void check_no_capabilities(const char *line, int len)
{
	if (strlen(line) != len)
		warning(_("ignoring capabilities after first line '%s'"),
			line + strlen(line));
}
 
static int process_ref(const char *line, int len, struct ref ***list,
		       unsigned int flags, struct oid_array *extra_have)
{
	struct object_id old_oid;
	const char *name;
 
	if (parse_oid_hex(line, &old_oid, &name))
		return 0;
	if (*name != ' ')
		return 0;
	name++;
 
	if (extra_have && !strcmp(name, ".have")) {
		oid_array_append(extra_have, &old_oid);
	} else if (!strcmp(name, "capabilities^{}")) {
		die(_("protocol error: unexpected capabilities^{}"));
	} else if (check_ref(name, flags)) {
		struct ref *ref = alloc_ref(name);
		oidcpy(&ref->old_oid, &old_oid);
		**list = ref;
		*list = &ref->next;
	}
	check_no_capabilities(line, len);
	return 1;
}
 
static int process_shallow(const char *line, int len,
			   struct oid_array *shallow_points)
{
	const char *arg;
	struct object_id old_oid;
 
	if (!skip_prefix(line, "shallow ", &arg))
		return 0;
 
	if (get_oid_hex(arg, &old_oid))
		die(_("protocol error: expected shallow sha-1, got '%s'"), arg);
	if (!shallow_points)
		die(_("repository on the other end cannot be shallow"));
	oid_array_append(shallow_points, &old_oid);
	check_no_capabilities(line, len);
	return 1;
}
 
enum get_remote_heads_state {
	EXPECTING_FIRST_REF = 0,
	EXPECTING_REF,
	EXPECTING_SHALLOW,
	EXPECTING_DONE,
};
 
/*
 * Read all the refs from the other end
 */
struct ref **get_remote_heads(struct packet_reader *reader,
			      struct ref **list, unsigned int flags,
			      struct oid_array *extra_have,
			      struct oid_array *shallow_points)
{
	struct ref **orig_list = list;
	int len = 0;
	enum get_remote_heads_state state = EXPECTING_FIRST_REF;
	const char *arg;
 
	*list = NULL;
 
	while (state != EXPECTING_DONE) {
		switch (packet_reader_read(reader)) {
		case PACKET_READ_EOF:
			die_initial_contact(1);
		case PACKET_READ_NORMAL:
			len = reader->pktlen;
			if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
				die(_("remote error: %s"), arg);
			break;
		case PACKET_READ_FLUSH:
			state = EXPECTING_DONE;
			break;
		case PACKET_READ_DELIM:
			die(_("invalid packet"));
		}
 
		switch (state) {
		case EXPECTING_FIRST_REF:
			process_capabilities(reader->line, &len);
			if (process_dummy_ref(reader->line)) {
				state = EXPECTING_SHALLOW;
				break;
			}
			state = EXPECTING_REF;
			/* fallthrough */
		case EXPECTING_REF:
			if (process_ref(reader->line, len, &list, flags, extra_have))
				break;
			state = EXPECTING_SHALLOW;
			/* fallthrough */
		case EXPECTING_SHALLOW:
			if (process_shallow(reader->line, len, shallow_points))
				break;
			die(_("protocol error: unexpected '%s'"), reader->line);
		case EXPECTING_DONE:
			break;
		}
	}
 
	annotate_refs_with_symref_info(*orig_list);
 
	return list;
}
 
/* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
static int process_ref_v2(const char *line, struct ref ***list)
{
	int ret = 1;
	int i = 0;
	struct object_id old_oid;
	struct ref *ref;
	struct string_list line_sections = STRING_LIST_INIT_DUP;
	const char *end;
 
	/*
	 * Ref lines have a number of fields which are space deliminated.  The
	 * first field is the OID of the ref.  The second field is the ref
	 * name.  Subsequent fields (symref-target and peeled) are optional and
	 * don't have a particular order.
	 */
	if (string_list_split(&line_sections, line, ' ', -1) < 2) {
		ret = 0;
		goto out;
	}
 
	if (parse_oid_hex(line_sections.items[i++].string, &old_oid, &end) ||
	    *end) {
		ret = 0;
		goto out;
	}
 
	ref = alloc_ref(line_sections.items[i++].string);
 
	oidcpy(&ref->old_oid, &old_oid);
	**list = ref;
	*list = &ref->next;
 
	for (; i < line_sections.nr; i++) {
		const char *arg = line_sections.items[i].string;
		if (skip_prefix(arg, "symref-target:", &arg))
			ref->symref = xstrdup(arg);
 
		if (skip_prefix(arg, "peeled:", &arg)) {
			struct object_id peeled_oid;
			char *peeled_name;
			struct ref *peeled;
			if (parse_oid_hex(arg, &peeled_oid, &end) || *end) {
				ret = 0;
				goto out;
			}
 
			peeled_name = xstrfmt("%s^{}", ref->name);
			peeled = alloc_ref(peeled_name);
 
			oidcpy(&peeled->old_oid, &peeled_oid);
			**list = peeled;
			*list = &peeled->next;
 
			free(peeled_name);
		}
	}
 
out:
	string_list_clear(&line_sections, 0);
	return ret;
}
 
struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
			     struct ref **list, int for_push,
			     const struct argv_array *ref_prefixes,
			     const struct string_list *server_options)
{
	int i;
	*list = NULL;
 
	if (server_supports_v2("ls-refs", 1))
		packet_write_fmt(fd_out, "command=ls-refs\n");
 
	if (server_supports_v2("agent", 0))
		packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 
	if (server_options && server_options->nr &&
	    server_supports_v2("server-option", 1))
		for (i = 0; i < server_options->nr; i++)
			packet_write_fmt(fd_out, "server-option=%s",
					 server_options->items[i].string);
 
	packet_delim(fd_out);
	/* When pushing we don't want to request the peeled tags */
	if (!for_push)
		packet_write_fmt(fd_out, "peel\n");
	packet_write_fmt(fd_out, "symrefs\n");
	for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
		packet_write_fmt(fd_out, "ref-prefix %s\n",
				 ref_prefixes->argv[i]);
	}
	packet_flush(fd_out);
 
	/* Process response from server */
	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
		if (!process_ref_v2(reader->line, &list))
			die(_("invalid ls-refs response: %s"), reader->line);
	}
 
	if (reader->status != PACKET_READ_FLUSH)
		die(_("expected flush after ref listing"));
 
	return list;
}
 
static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
{
	int len;
 
	if (!feature_list)
		return NULL;
 
	len = strlen(feature);
	while (*feature_list) {
		const char *found = strstr(feature_list, feature);
		if (!found)
			return NULL;
		if (feature_list == found || isspace(found[-1])) {
			const char *value = found + len;
			/* feature with no value (e.g., "thin-pack") */
			if (!*value || isspace(*value)) {
				if (lenp)
					*lenp = 0;
				return value;
			}
			/* feature with a value (e.g., "agent=git/1.2.3") */
			else if (*value == '=') {
				value++;
				if (lenp)
					*lenp = strcspn(value, " \t\n");
				return value;
			}
			/*
			 * otherwise we matched a substring of another feature;
			 * keep looking
			 */
		}
		feature_list = found + 1;
	}
	return NULL;
}
 
int parse_feature_request(const char *feature_list, const char *feature)
{
	return !!parse_feature_value(feature_list, feature, NULL);
}
 
const char *server_feature_value(const char *feature, int *len)
{
	return parse_feature_value(server_capabilities_v1, feature, len);
}
 
int server_supports(const char *feature)
{
	return !!server_feature_value(feature, NULL);
}
 
enum protocol {
	PROTO_LOCAL = 1,
	PROTO_FILE,
	PROTO_SSH,
	PROTO_GIT
};
 
int url_is_local_not_ssh(const char *url)
{
	const char *colon = strchr(url, ':');
	const char *slash = strchr(url, '/');
	return !colon || (slash && slash < colon) ||
		has_dos_drive_prefix(url);
}
 
static const char *prot_name(enum protocol protocol)
{
	switch (protocol) {
		case PROTO_LOCAL:
		case PROTO_FILE:
			return "file";
		case PROTO_SSH:
			return "ssh";
		case PROTO_GIT:
			return "git";
		default:
			return "unknown protocol";
	}
}
 
static enum protocol get_protocol(const char *name)
{
	if (!strcmp(name, "ssh"))
		return PROTO_SSH;
	if (!strcmp(name, "git"))
		return PROTO_GIT;
	if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
		return PROTO_SSH;
	if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
		return PROTO_SSH;
	if (!strcmp(name, "file"))
		return PROTO_FILE;
	die(_("protocol '%s' is not supported"), name);
}
 
static char *host_end(char **hoststart, int removebrackets)
{
	char *host = *hoststart;
	char *end;
	char *start = strstr(host, "@[");
	if (start)
		start++; /* Jump over '@' */
	else
		start = host;
	if (start[0] == '[') {
		end = strchr(start + 1, ']');
		if (end) {
			if (removebrackets) {
				*end = 0;
				memmove(start, start + 1, end - start);
				end++;
			}
		} else
			end = host;
	} else
		end = host;
	return end;
}
 
#define STR_(s)	# s
#define STR(s)	STR_(s)
 
static void get_host_and_port(char **host, const char **port)
{
	char *colon, *end;
	end = host_end(host, 1);
	colon = strchr(end, ':');
	if (colon) {
		long portnr = strtol(colon + 1, &end, 10);
		if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
			*colon = 0;
			*port = colon + 1;
		} else if (!colon[1]) {
			*colon = 0;
		}
	}
}
 
static void enable_keepalive(int sockfd)
{
	int ka = 1;
 
	if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
		error_errno(_("unable to set SO_KEEPALIVE on socket"));
}
 
#ifndef NO_IPV6
 
static const char *ai_name(const struct addrinfo *ai)
{
	static char addr[NI_MAXHOST];
	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
			NI_NUMERICHOST) != 0)
		xsnprintf(addr, sizeof(addr), "(unknown)");
 
	return addr;
}
 
/*
 * Returns a connected socket() fd, or else die()s.
 */
static int git_tcp_connect_sock(char *host, int flags)
{
	struct strbuf error_message = STRBUF_INIT;
	int sockfd = -1;
	const char *port = STR(DEFAULT_GIT_PORT);
	struct addrinfo hints, *ai0, *ai;
	int gai;
	int cnt = 0;
 
	get_host_and_port(&host, &port);
	if (!*port)
		port = "<none>";
 
	memset(&hints, 0, sizeof(hints));
	if (flags & CONNECT_IPV4)
		hints.ai_family = AF_INET;
	else if (flags & CONNECT_IPV6)
		hints.ai_family = AF_INET6;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_protocol = IPPROTO_TCP;
 
	if (flags & CONNECT_VERBOSE)
		fprintf(stderr, _("Looking up %s ... "), host);
 
	gai = getaddrinfo(host, port, &hints, &ai);
	if (gai)
		die(_("unable to look up %s (port %s) (%s)"), host, port, gai_strerror(gai));
 
	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Looking up %s ... " */
		fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 
	for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
		sockfd = socket(ai->ai_family,
				ai->ai_socktype, ai->ai_protocol);
		if ((sockfd < 0) ||
		    (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
			strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
				    host, cnt, ai_name(ai), strerror(errno));
			if (0 <= sockfd)
				close(sockfd);
			sockfd = -1;
			continue;
		}
		if (flags & CONNECT_VERBOSE)
			fprintf(stderr, "%s ", ai_name(ai));
		break;
	}
 
	freeaddrinfo(ai0);
 
	if (sockfd < 0)
		die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 
	enable_keepalive(sockfd);
 
	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
		fprintf_ln(stderr, _("done."));
 
	strbuf_release(&error_message);
 
	return sockfd;
}
 
#else /* NO_IPV6 */
 
/*
 * Returns a connected socket() fd, or else die()s.
 */
static int git_tcp_connect_sock(char *host, int flags)
{
	struct strbuf error_message = STRBUF_INIT;
	int sockfd = -1;
	const char *port = STR(DEFAULT_GIT_PORT);
	char *ep;
	struct hostent *he;
	struct sockaddr_in sa;
	char **ap;
	unsigned int nport;
	int cnt;
 
	get_host_and_port(&host, &port);
 
	if (flags & CONNECT_VERBOSE)
		fprintf(stderr, _("Looking up %s ... "), host);
 
	he = gethostbyname(host);
	if (!he)
		die(_("unable to look up %s (%s)"), host, hstrerror(h_errno));
	nport = strtoul(port, &ep, 10);
	if ( ep == port || *ep ) {
		/* Not numeric */
		struct servent *se = getservbyname(port,"tcp");
		if ( !se )
			die(_("unknown port %s"), port);
		nport = se->s_port;
	}
 
	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Looking up %s ... " */
		fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 
	for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
		memset(&sa, 0, sizeof sa);
		sa.sin_family = he->h_addrtype;
		sa.sin_port = htons(nport);
		memcpy(&sa.sin_addr, *ap, he->h_length);
 
		sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
		if ((sockfd < 0) ||
		    connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
			strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
				host,
				cnt,
				inet_ntoa(*(struct in_addr *)&sa.sin_addr),
				strerror(errno));
			if (0 <= sockfd)
				close(sockfd);
			sockfd = -1;
			continue;
		}
		if (flags & CONNECT_VERBOSE)
			fprintf(stderr, "%s ",
				inet_ntoa(*(struct in_addr *)&sa.sin_addr));
		break;
	}
 
	if (sockfd < 0)
		die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 
	enable_keepalive(sockfd);
 
	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
		fprintf_ln(stderr, _("done."));
 
	return sockfd;
}
 
#endif /* NO_IPV6 */
 
 
/*
 * Dummy child_process returned by git_connect() if the transport protocol
 * does not need fork(2).
 */
static struct child_process no_fork = CHILD_PROCESS_INIT;
 
int git_connection_is_socket(struct child_process *conn)
{
	return conn == &no_fork;
}
 
static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
{
	int sockfd = git_tcp_connect_sock(host, flags);
 
	fd[0] = sockfd;
	fd[1] = dup(sockfd);
 
	return &no_fork;
}
 
 
static char *git_proxy_command;
 
static int git_proxy_command_options(const char *var, const char *value,
		void *cb)
{
	if (!strcmp(var, "core.gitproxy")) {
		const char *for_pos;
		int matchlen = -1;
		int hostlen;
		const char *rhost_name = cb;
		int rhost_len = strlen(rhost_name);
 
		if (git_proxy_command)
			return 0;
		if (!value)
			return config_error_nonbool(var);
		/* [core]
		 * ;# matches www.kernel.org as well
		 * gitproxy = netcatter-1 for kernel.org
		 * gitproxy = netcatter-2 for sample.xz
		 * gitproxy = netcatter-default
		 */
		for_pos = strstr(value, " for ");
		if (!for_pos)
			/* matches everybody */
			matchlen = strlen(value);
		else {
			hostlen = strlen(for_pos + 5);
			if (rhost_len < hostlen)
				matchlen = -1;
			else if (!strncmp(for_pos + 5,
					  rhost_name + rhost_len - hostlen,
					  hostlen) &&
				 ((rhost_len == hostlen) ||
				  rhost_name[rhost_len - hostlen -1] == '.'))
				matchlen = for_pos - value;
			else
				matchlen = -1;
		}
		if (0 <= matchlen) {
			/* core.gitproxy = none for kernel.org */
			if (matchlen == 4 &&
			    !memcmp(value, "none", 4))
				matchlen = 0;
			git_proxy_command = xmemdupz(value, matchlen);
		}
		return 0;
	}
 
	return git_default_config(var, value, cb);
}
 
static int git_use_proxy(const char *host)
{
	git_proxy_command = getenv("GIT_PROXY_COMMAND");
	git_config(git_proxy_command_options, (void*)host);
	return (git_proxy_command && *git_proxy_command);
}
 
static struct child_process *git_proxy_connect(int fd[2], char *host)
{
	const char *port = STR(DEFAULT_GIT_PORT);
	struct child_process *proxy;
 
	get_host_and_port(&host, &port);
 
	if (looks_like_command_line_option(host))
		die(_("strange hostname '%s' blocked"), host);
	if (looks_like_command_line_option(port))
		die(_("strange port '%s' blocked"), port);
 
	proxy = xmalloc(sizeof(*proxy));
	child_process_init(proxy);
	argv_array_push(&proxy->args, git_proxy_command);
	argv_array_push(&proxy->args, host);
	argv_array_push(&proxy->args, port);
	proxy->in = -1;
	proxy->out = -1;
	if (start_command(proxy))
		die(_("cannot start proxy %s"), git_proxy_command);
	fd[0] = proxy->out; /* read from proxy stdout */
	fd[1] = proxy->in;  /* write to proxy stdin */
	return proxy;
}
 
static char *get_port(char *host)
{
	char *end;
	char *p = strchr(host, ':');
 
	if (p) {
		long port = strtol(p + 1, &end, 10);
		if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
			*p = '\0';
			return p+1;
		}
	}
 
	return NULL;
}
 
/*
 * Extract protocol and relevant parts from the specified connection URL.
 * The caller must free() the returned strings.
 */
static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
				       char **ret_path)
{
	char *url;
	char *host, *path;
	char *end;
	int separator = '/';
	enum protocol protocol = PROTO_LOCAL;
 
	if (is_url(url_orig))
		url = url_decode(url_orig);
	else
		url = xstrdup(url_orig);
 
	host = strstr(url, "://");
	if (host) {
		*host = '\0';
		protocol = get_protocol(url);
		host += 3;
	} else {
		host = url;
		if (!url_is_local_not_ssh(url)) {
			protocol = PROTO_SSH;
			separator = ':';
		}
	}
 
	/*
	 * Don't do destructive transforms as protocol code does
	 * '[]' unwrapping in get_host_and_port()
	 */
	end = host_end(&host, 0);
 
	if (protocol == PROTO_LOCAL)
		path = end;
	else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
		path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
	else
		path = strchr(end, separator);
 
	if (!path || !*path)
		die(_("no path specified; see 'git help pull' for valid url syntax"));
 
	/*
	 * null-terminate hostname and point path to ~ for URL's like this:
	 *    ssh://host.xz/~user/repo
	 */
 
	end = path; /* Need to \0 terminate host here */
	if (separator == ':')
		path++; /* path starts after ':' */
	if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
		if (path[1] == '~')
			path++;
	}
 
	path = xstrdup(path);
	*end = '\0';
 
	*ret_host = xstrdup(host);
	*ret_path = path;
	free(url);
	return protocol;
}
 
static const char *get_ssh_command(void)
{
	const char *ssh;
 
	if ((ssh = getenv("GIT_SSH_COMMAND")))
		return ssh;
 
	if (!git_config_get_string_const("core.sshcommand", &ssh))
		return ssh;
 
	return NULL;
}
 
enum ssh_variant {
	VARIANT_AUTO,
	VARIANT_SIMPLE,
	VARIANT_SSH,
	VARIANT_PLINK,
	VARIANT_PUTTY,
	VARIANT_TORTOISEPLINK,
};
 
static void override_ssh_variant(enum ssh_variant *ssh_variant)
{
	const char *variant = getenv("GIT_SSH_VARIANT");
 
	if (!variant && git_config_get_string_const("ssh.variant", &variant))
		return;
 
	if (!strcmp(variant, "auto"))
		*ssh_variant = VARIANT_AUTO;
	else if (!strcmp(variant, "plink"))
		*ssh_variant = VARIANT_PLINK;
	else if (!strcmp(variant, "putty"))
		*ssh_variant = VARIANT_PUTTY;
	else if (!strcmp(variant, "tortoiseplink"))
		*ssh_variant = VARIANT_TORTOISEPLINK;
	else if (!strcmp(variant, "simple"))
		*ssh_variant = VARIANT_SIMPLE;
	else
		*ssh_variant = VARIANT_SSH;
}
 
static enum ssh_variant determine_ssh_variant(const char *ssh_command,
					      int is_cmdline)
{
	enum ssh_variant ssh_variant = VARIANT_AUTO;
	const char *variant;
	char *p = NULL;
 
	override_ssh_variant(&ssh_variant);
 
	if (ssh_variant != VARIANT_AUTO)
		return ssh_variant;
 
	if (!is_cmdline) {
		p = xstrdup(ssh_command);
		variant = basename(p);
	} else {
		const char **ssh_argv;
 
		p = xstrdup(ssh_command);
		if (split_cmdline(p, &ssh_argv) > 0) {
			variant = basename((char *)ssh_argv[0]);
			/*
			 * At this point, variant points into the buffer
			 * referenced by p, hence we do not need ssh_argv
			 * any longer.
			 */
			free(ssh_argv);
		} else {
			free(p);
			return ssh_variant;
		}
	}
 
	if (!strcasecmp(variant, "ssh") ||
	    !strcasecmp(variant, "ssh.exe"))
		ssh_variant = VARIANT_SSH;
	else if (!strcasecmp(variant, "plink") ||
		 !strcasecmp(variant, "plink.exe"))
		ssh_variant = VARIANT_PLINK;
	else if (!strcasecmp(variant, "tortoiseplink") ||
		 !strcasecmp(variant, "tortoiseplink.exe"))
		ssh_variant = VARIANT_TORTOISEPLINK;
 
	free(p);
	return ssh_variant;
}
 
/*
 * Open a connection using Git's native protocol.
 *
 * The caller is responsible for freeing hostandport, but this function may
 * modify it (for example, to truncate it to remove the port part).
 */
static struct child_process *git_connect_git(int fd[2], char *hostandport,
					     const char *path, const char *prog,
					     enum protocol_version version,
					     int flags)
{
	struct child_process *conn;
	struct strbuf request = STRBUF_INIT;
	/*
	 * Set up virtual host information based on where we will
	 * connect, unless the user has overridden us in
	 * the environment.
	 */
	char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
	if (target_host)
		target_host = xstrdup(target_host);
	else
		target_host = xstrdup(hostandport);
 
	transport_check_allowed("git");
 
	/*
	 * These underlying connection commands die() if they
	 * cannot connect.
	 */
	if (git_use_proxy(hostandport))
		conn = git_proxy_connect(fd, hostandport);
	else
		conn = git_tcp_connect(fd, hostandport, flags);
	/*
	 * Separate original protocol components prog and path
	 * from extended host header with a NUL byte.
	 *
	 * Note: Do not add any other headers here!  Doing so
	 * will cause older git-daemon servers to crash.
	 */
	strbuf_addf(&request,
		    "%s %s%chost=%s%c",
		    prog, path, 0,
		    target_host, 0);
 
	/* If using a new version put that stuff here after a second null byte */
	if (version > 0) {
		strbuf_addch(&request, '\0');
		strbuf_addf(&request, "version=%d%c",
			    version, '\0');
	}
 
	packet_write(fd[1], request.buf, request.len);
 
	free(target_host);
	strbuf_release(&request);
	return conn;
}
 
/*
 * Append the appropriate environment variables to `env` and options to
 * `args` for running ssh in Git's SSH-tunneled transport.
 */
static void push_ssh_options(struct argv_array *args, struct argv_array *env,
			     enum ssh_variant variant, const char *port,
			     enum protocol_version version, int flags)
{
	if (variant == VARIANT_SSH &&
	    version > 0) {
		argv_array_push(args, "-o");
		argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
		argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
				 version);
	}
 
	if (flags & CONNECT_IPV4) {
		switch (variant) {
		case VARIANT_AUTO:
			BUG("VARIANT_AUTO passed to push_ssh_options");
		case VARIANT_SIMPLE:
			die(_("ssh variant 'simple' does not support -4"));
		case VARIANT_SSH:
		case VARIANT_PLINK:
		case VARIANT_PUTTY:
		case VARIANT_TORTOISEPLINK:
			argv_array_push(args, "-4");
		}
	} else if (flags & CONNECT_IPV6) {
		switch (variant) {
		case VARIANT_AUTO:
			BUG("VARIANT_AUTO passed to push_ssh_options");
		case VARIANT_SIMPLE:
			die(_("ssh variant 'simple' does not support -6"));
		case VARIANT_SSH:
		case VARIANT_PLINK:
		case VARIANT_PUTTY:
		case VARIANT_TORTOISEPLINK:
			argv_array_push(args, "-6");
		}
	}
 
	if (variant == VARIANT_TORTOISEPLINK)
		argv_array_push(args, "-batch");
 
	if (port) {
		switch (variant) {
		case VARIANT_AUTO:
			BUG("VARIANT_AUTO passed to push_ssh_options");
		case VARIANT_SIMPLE:
			die(_("ssh variant 'simple' does not support setting port"));
		case VARIANT_SSH:
			argv_array_push(args, "-p");
			break;
		case VARIANT_PLINK:
		case VARIANT_PUTTY:
		case VARIANT_TORTOISEPLINK:
			argv_array_push(args, "-P");
		}
 
		argv_array_push(args, port);
	}
}
 
/* Prepare a child_process for use by Git's SSH-tunneled transport. */
static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
			  const char *port, enum protocol_version version,
			  int flags)
{
	const char *ssh;
	enum ssh_variant variant;
 
	if (looks_like_command_line_option(ssh_host))
		die(_("strange hostname '%s' blocked"), ssh_host);
 
	ssh = get_ssh_command();
	if (ssh) {
		variant = determine_ssh_variant(ssh, 1);
	} else {
		/*
		 * GIT_SSH is the no-shell version of
		 * GIT_SSH_COMMAND (and must remain so for
		 * historical compatibility).
		 */
		conn->use_shell = 0;
 
		ssh = getenv("GIT_SSH");
		if (!ssh)
			ssh = "ssh";
		variant = determine_ssh_variant(ssh, 0);
	}
 
	if (variant == VARIANT_AUTO) {
		struct child_process detect = CHILD_PROCESS_INIT;
 
		detect.use_shell = conn->use_shell;
		detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
 
		argv_array_push(&detect.args, ssh);
		argv_array_push(&detect.args, "-G");
		push_ssh_options(&detect.args, &detect.env_array,
				 VARIANT_SSH, port, version, flags);
		argv_array_push(&detect.args, ssh_host);
 
		variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
	}
 
	argv_array_push(&conn->args, ssh);
	push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
	argv_array_push(&conn->args, ssh_host);
}
 
/*
 * This returns the dummy child_process `no_fork` if the transport protocol
 * does not need fork(2), or a struct child_process object if it does.  Once
 * done, finish the connection with finish_connect() with the value returned
 * from this function (it is safe to call finish_connect() with NULL to
 * support the former case).
 *
 * If it returns, the connect is successful; it just dies on errors (this
 * will hopefully be changed in a libification effort, to return NULL when
 * the connection failed).
 */
struct child_process *git_connect(int fd[2], const char *url,
				  const char *prog, int flags)
{
	char *hostandport, *path;
	struct child_process *conn;
	enum protocol protocol;
	enum protocol_version version = get_protocol_version_config();
 
	/*
	 * NEEDSWORK: If we are trying to use protocol v2 and we are planning
	 * to perform a push, then fallback to v0 since the client doesn't know
	 * how to push yet using v2.
	 */
	if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
		version = protocol_v0;
 
	/* Without this we cannot rely on waitpid() to tell
	 * what happened to our children.
	 */
	signal(SIGCHLD, SIG_DFL);
 
	protocol = parse_connect_url(url, &hostandport, &path);
	if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
		printf("Diag: url=%s\n", url ? url : "NULL");
		printf("Diag: protocol=%s\n", prot_name(protocol));
		printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
		printf("Diag: path=%s\n", path ? path : "NULL");
		conn = NULL;
	} else if (protocol == PROTO_GIT) {
		conn = git_connect_git(fd, hostandport, path, prog, version, flags);
	} else {
		struct strbuf cmd = STRBUF_INIT;
		const char *const *var;
 
		conn = xmalloc(sizeof(*conn));
		child_process_init(conn);
 
		if (looks_like_command_line_option(path))
			die(_("strange pathname '%s' blocked"), path);
 
		strbuf_addstr(&cmd, prog);
		strbuf_addch(&cmd, ' ');
		sq_quote_buf(&cmd, path);
 
		/* remove repo-local variables from the environment */
		for (var = local_repo_env; *var; var++)
			argv_array_push(&conn->env_array, *var);
 
		conn->use_shell = 1;
		conn->in = conn->out = -1;
		if (protocol == PROTO_SSH) {
			char *ssh_host = hostandport;
			const char *port = NULL;
			transport_check_allowed("ssh");
			get_host_and_port(&ssh_host, &port);
 
			if (!port)
				port = get_port(ssh_host);
 
			if (flags & CONNECT_DIAG_URL) {
				printf("Diag: url=%s\n", url ? url : "NULL");
				printf("Diag: protocol=%s\n", prot_name(protocol));
				printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
				printf("Diag: port=%s\n", port ? port : "NONE");
				printf("Diag: path=%s\n", path ? path : "NULL");
 
				free(hostandport);
				free(path);
				free(conn);
				strbuf_release(&cmd);
				return NULL;
			}
			fill_ssh_args(conn, ssh_host, port, version, flags);
		} else {
			transport_check_allowed("file");
			if (version > 0) {
				argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
						 version);
			}
		}
		argv_array_push(&conn->args, cmd.buf);
 
		if (start_command(conn))
			die(_("unable to fork"));
 
		fd[0] = conn->out; /* read from child's stdout */
		fd[1] = conn->in;  /* write to child's stdin */
		strbuf_release(&cmd);
	}
	free(hostandport);
	free(path);
	return conn;
}
 
int finish_connect(struct child_process *conn)
{
	int code;
	if (!conn || git_connection_is_socket(conn))
		return 0;
 
	code = finish_command(conn);
	free(conn);
	return code;
}