summaryrefslogtreecommitdiff
path: root/transport-helper.c
blob: bf225c698fac81a9a94eff6d3371988ac4ff0bac (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
#include "cache.h"
#include "transport.h"
#include "quote.h"
#include "run-command.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "remote.h"
#include "string-list.h"
#include "thread-utils.h"
#include "sigchain.h"
#include "argv-array.h"
#include "refs.h"
#include "refspec.h"
#include "transport-internal.h"
#include "protocol.h"
 
static int debug;
 
struct helper_data {
	const char *name;
	struct child_process *helper;
	FILE *out;
	unsigned fetch : 1,
		import : 1,
		bidi_import : 1,
		export : 1,
		option : 1,
		push : 1,
		connect : 1,
		stateless_connect : 1,
		signed_tags : 1,
		check_connectivity : 1,
		no_disconnect_req : 1,
		no_private_update : 1;
	char *export_marks;
	char *import_marks;
	/* These go from remote name (as in "list") to private name */
	struct refspec rs;
	/* Transport options for fetch-pack/send-pack (should one of
	 * those be invoked).
	 */
	struct git_transport_options transport_options;
};
 
static void sendline(struct helper_data *helper, struct strbuf *buffer)
{
	if (debug)
		fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
	if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
		die_errno(_("full write to remote helper failed"));
}
 
static int recvline_fh(FILE *helper, struct strbuf *buffer)
{
	strbuf_reset(buffer);
	if (debug)
		fprintf(stderr, "Debug: Remote helper: Waiting...\n");
	if (strbuf_getline(buffer, helper) == EOF) {
		if (debug)
			fprintf(stderr, "Debug: Remote helper quit.\n");
		return 1;
	}
 
	if (debug)
		fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
	return 0;
}
 
static int recvline(struct helper_data *helper, struct strbuf *buffer)
{
	return recvline_fh(helper->out, buffer);
}
 
static void write_constant(int fd, const char *str)
{
	if (debug)
		fprintf(stderr, "Debug: Remote helper: -> %s", str);
	if (write_in_full(fd, str, strlen(str)) < 0)
		die_errno(_("full write to remote helper failed"));
}
 
static const char *remove_ext_force(const char *url)
{
	if (url) {
		const char *colon = strchr(url, ':');
		if (colon && colon[1] == ':')
			return colon + 2;
	}
	return url;
}
 
static void do_take_over(struct transport *transport)
{
	struct helper_data *data;
	data = (struct helper_data *)transport->data;
	transport_take_over(transport, data->helper);
	fclose(data->out);
	free(data);
}
 
static void standard_options(struct transport *t);
 
static struct child_process *get_helper(struct transport *transport)
{
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	struct child_process *helper;
	int duped;
	int code;
 
	if (data->helper)
		return data->helper;
 
	helper = xmalloc(sizeof(*helper));
	child_process_init(helper);
	helper->in = -1;
	helper->out = -1;
	helper->err = 0;
	argv_array_pushf(&helper->args, "git-remote-%s", data->name);
	argv_array_push(&helper->args, transport->remote->name);
	argv_array_push(&helper->args, remove_ext_force(transport->url));
	helper->git_cmd = 0;
	helper->silent_exec_failure = 1;
 
	if (have_git_dir())
		argv_array_pushf(&helper->env_array, "%s=%s",
				 GIT_DIR_ENVIRONMENT, get_git_dir());
 
	code = start_command(helper);
	if (code < 0 && errno == ENOENT)
		die(_("unable to find remote helper for '%s'"), data->name);
	else if (code != 0)
		exit(code);
 
	data->helper = helper;
	data->no_disconnect_req = 0;
	refspec_init(&data->rs, REFSPEC_FETCH);
 
	/*
	 * Open the output as FILE* so strbuf_getline_*() family of
	 * functions can be used.
	 * Do this with duped fd because fclose() will close the fd,
	 * and stuff like taking over will require the fd to remain.
	 */
	duped = dup(helper->out);
	if (duped < 0)
		die_errno(_("can't dup helper output fd"));
	data->out = xfdopen(duped, "r");
 
	write_constant(helper->in, "capabilities\n");
 
	while (1) {
		const char *capname, *arg;
		int mandatory = 0;
		if (recvline(data, &buf))
			exit(128);
 
		if (!*buf.buf)
			break;
 
		if (*buf.buf == '*') {
			capname = buf.buf + 1;
			mandatory = 1;
		} else
			capname = buf.buf;
 
		if (debug)
			fprintf(stderr, "Debug: Got cap %s\n", capname);
		if (!strcmp(capname, "fetch"))
			data->fetch = 1;
		else if (!strcmp(capname, "option"))
			data->option = 1;
		else if (!strcmp(capname, "push"))
			data->push = 1;
		else if (!strcmp(capname, "import"))
			data->import = 1;
		else if (!strcmp(capname, "bidi-import"))
			data->bidi_import = 1;
		else if (!strcmp(capname, "export"))
			data->export = 1;
		else if (!strcmp(capname, "check-connectivity"))
			data->check_connectivity = 1;
		else if (skip_prefix(capname, "refspec ", &arg)) {
			refspec_append(&data->rs, arg);
		} else if (!strcmp(capname, "connect")) {
			data->connect = 1;
		} else if (!strcmp(capname, "stateless-connect")) {
			data->stateless_connect = 1;
		} else if (!strcmp(capname, "signed-tags")) {
			data->signed_tags = 1;
		} else if (skip_prefix(capname, "export-marks ", &arg)) {
			data->export_marks = xstrdup(arg);
		} else if (skip_prefix(capname, "import-marks ", &arg)) {
			data->import_marks = xstrdup(arg);
		} else if (starts_with(capname, "no-private-update")) {
			data->no_private_update = 1;
		} else if (mandatory) {
			die(_("unknown mandatory capability %s; this remote "
			      "helper probably needs newer version of Git"),
			    capname);
		}
	}
	if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
		warning(_("this remote helper should implement refspec capability"));
	}
	strbuf_release(&buf);
	if (debug)
		fprintf(stderr, "Debug: Capabilities complete.\n");
	standard_options(transport);
	return data->helper;
}
 
static int disconnect_helper(struct transport *transport)
{
	struct helper_data *data = transport->data;
	int res = 0;
 
	if (data->helper) {
		if (debug)
			fprintf(stderr, "Debug: Disconnecting.\n");
		if (!data->no_disconnect_req) {
			/*
			 * Ignore write errors; there's nothing we can do,
			 * since we're about to close the pipe anyway. And the
			 * most likely error is EPIPE due to the helper dying
			 * to report an error itself.
			 */
			sigchain_push(SIGPIPE, SIG_IGN);
			xwrite(data->helper->in, "\n", 1);
			sigchain_pop(SIGPIPE);
		}
		close(data->helper->in);
		close(data->helper->out);
		fclose(data->out);
		res = finish_command(data->helper);
		FREE_AND_NULL(data->helper);
	}
	return res;
}
 
static const char *unsupported_options[] = {
	TRANS_OPT_UPLOADPACK,
	TRANS_OPT_RECEIVEPACK,
	TRANS_OPT_THIN,
	TRANS_OPT_KEEP
	};
 
static const char *boolean_options[] = {
	TRANS_OPT_THIN,
	TRANS_OPT_KEEP,
	TRANS_OPT_FOLLOWTAGS,
	TRANS_OPT_DEEPEN_RELATIVE
	};
 
static int strbuf_set_helper_option(struct helper_data *data,
				    struct strbuf *buf)
{
	int ret;
 
	sendline(data, buf);
	if (recvline(data, buf))
		exit(128);
 
	if (!strcmp(buf->buf, "ok"))
		ret = 0;
	else if (starts_with(buf->buf, "error"))
		ret = -1;
	else if (!strcmp(buf->buf, "unsupported"))
		ret = 1;
	else {
		warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
		ret = 1;
	}
	return ret;
}
 
static int string_list_set_helper_option(struct helper_data *data,
					 const char *name,
					 struct string_list *list)
{
	struct strbuf buf = STRBUF_INIT;
	int i, ret = 0;
 
	for (i = 0; i < list->nr; i++) {
		strbuf_addf(&buf, "option %s ", name);
		quote_c_style(list->items[i].string, &buf, NULL, 0);
		strbuf_addch(&buf, '\n');
 
		if ((ret = strbuf_set_helper_option(data, &buf)))
			break;
		strbuf_reset(&buf);
	}
	strbuf_release(&buf);
	return ret;
}
 
static int set_helper_option(struct transport *transport,
			  const char *name, const char *value)
{
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	int i, ret, is_bool = 0;
 
	get_helper(transport);
 
	if (!data->option)
		return 1;
 
	if (!strcmp(name, "deepen-not"))
		return string_list_set_helper_option(data, name,
						     (struct string_list *)value);
 
	for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
		if (!strcmp(name, unsupported_options[i]))
			return 1;
	}
 
	for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
		if (!strcmp(name, boolean_options[i])) {
			is_bool = 1;
			break;
		}
	}
 
	strbuf_addf(&buf, "option %s ", name);
	if (is_bool)
		strbuf_addstr(&buf, value ? "true" : "false");
	else
		quote_c_style(value, &buf, NULL, 0);
	strbuf_addch(&buf, '\n');
 
	ret = strbuf_set_helper_option(data, &buf);
	strbuf_release(&buf);
	return ret;
}
 
static void standard_options(struct transport *t)
{
	char buf[16];
	int v = t->verbose;
 
	set_helper_option(t, "progress", t->progress ? "true" : "false");
 
	xsnprintf(buf, sizeof(buf), "%d", v + 1);
	set_helper_option(t, "verbosity", buf);
 
	switch (t->family) {
	case TRANSPORT_FAMILY_ALL:
		/*
		 * this is already the default,
		 * do not break old remote helpers by setting "all" here
		 */
		break;
	case TRANSPORT_FAMILY_IPV4:
		set_helper_option(t, "family", "ipv4");
		break;
	case TRANSPORT_FAMILY_IPV6:
		set_helper_option(t, "family", "ipv6");
		break;
	}
}
 
static int release_helper(struct transport *transport)
{
	int res = 0;
	struct helper_data *data = transport->data;
	refspec_clear(&data->rs);
	res = disconnect_helper(transport);
	free(transport->data);
	return res;
}
 
static int fetch_with_fetch(struct transport *transport,
			    int nr_heads, struct ref **to_fetch)
{
	struct helper_data *data = transport->data;
	int i;
	struct strbuf buf = STRBUF_INIT;
 
	for (i = 0; i < nr_heads; i++) {
		const struct ref *posn = to_fetch[i];
		if (posn->status & REF_STATUS_UPTODATE)
			continue;
 
		strbuf_addf(&buf, "fetch %s %s\n",
			    oid_to_hex(&posn->old_oid),
			    posn->symref ? posn->symref : posn->name);
	}
 
	strbuf_addch(&buf, '\n');
	sendline(data, &buf);
 
	while (1) {
		if (recvline(data, &buf))
			exit(128);
 
		if (starts_with(buf.buf, "lock ")) {
			const char *name = buf.buf + 5;
			if (transport->pack_lockfile)
				warning(_("%s also locked %s"), data->name, name);
			else
				transport->pack_lockfile = xstrdup(name);
		}
		else if (data->check_connectivity &&
			 data->transport_options.check_self_contained_and_connected &&
			 !strcmp(buf.buf, "connectivity-ok"))
			data->transport_options.self_contained_and_connected = 1;
		else if (!buf.len)
			break;
		else
			warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
	}
	strbuf_release(&buf);
	return 0;
}
 
static int get_importer(struct transport *transport, struct child_process *fastimport)
{
	struct child_process *helper = get_helper(transport);
	struct helper_data *data = transport->data;
	int cat_blob_fd, code;
	child_process_init(fastimport);
	fastimport->in = helper->out;
	argv_array_push(&fastimport->args, "fast-import");
	argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 
	if (data->bidi_import) {
		cat_blob_fd = xdup(helper->in);
		argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
	}
	fastimport->git_cmd = 1;
 
	code = start_command(fastimport);
	return code;
}
 
static int get_exporter(struct transport *transport,
			struct child_process *fastexport,
			struct string_list *revlist_args)
{
	struct helper_data *data = transport->data;
	struct child_process *helper = get_helper(transport);
	int i;
 
	child_process_init(fastexport);
 
	/* we need to duplicate helper->in because we want to use it after
	 * fastexport is done with it. */
	fastexport->out = dup(helper->in);
	argv_array_push(&fastexport->args, "fast-export");
	argv_array_push(&fastexport->args, "--use-done-feature");
	argv_array_push(&fastexport->args, data->signed_tags ?
		"--signed-tags=verbatim" : "--signed-tags=warn-strip");
	if (data->export_marks)
		argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
	if (data->import_marks)
		argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 
	for (i = 0; i < revlist_args->nr; i++)
		argv_array_push(&fastexport->args, revlist_args->items[i].string);
 
	fastexport->git_cmd = 1;
	return start_command(fastexport);
}
 
static int fetch_with_import(struct transport *transport,
			     int nr_heads, struct ref **to_fetch)
{
	struct child_process fastimport;
	struct helper_data *data = transport->data;
	int i;
	struct ref *posn;
	struct strbuf buf = STRBUF_INIT;
 
	get_helper(transport);
 
	if (get_importer(transport, &fastimport))
		die(_("couldn't run fast-import"));
 
	for (i = 0; i < nr_heads; i++) {
		posn = to_fetch[i];
		if (posn->status & REF_STATUS_UPTODATE)
			continue;
 
		strbuf_addf(&buf, "import %s\n",
			    posn->symref ? posn->symref : posn->name);
		sendline(data, &buf);
		strbuf_reset(&buf);
	}
 
	write_constant(data->helper->in, "\n");
	/*
	 * remote-helpers that advertise the bidi-import capability are required to
	 * buffer the complete batch of import commands until this newline before
	 * sending data to fast-import.
	 * These helpers read back data from fast-import on their stdin, which could
	 * be mixed with import commands, otherwise.
	 */
 
	if (finish_command(&fastimport))
		die(_("error while running fast-import"));
 
	/*
	 * The fast-import stream of a remote helper that advertises
	 * the "refspec" capability writes to the refs named after the
	 * right hand side of the first refspec matching each ref we
	 * were fetching.
	 *
	 * (If no "refspec" capability was specified, for historical
	 * reasons we default to the equivalent of *:*.)
	 *
	 * Store the result in to_fetch[i].old_sha1.  Callers such
	 * as "git fetch" can use the value to write feedback to the
	 * terminal, populate FETCH_HEAD, and determine what new value
	 * should be written to peer_ref if the update is a
	 * fast-forward or this is a forced update.
	 */
	for (i = 0; i < nr_heads; i++) {
		char *private, *name;
		posn = to_fetch[i];
		if (posn->status & REF_STATUS_UPTODATE)
			continue;
		name = posn->symref ? posn->symref : posn->name;
		if (data->rs.nr)
			private = apply_refspecs(&data->rs, name);
		else
			private = xstrdup(name);
		if (private) {
			if (read_ref(private, &posn->old_oid) < 0)
				die(_("could not read ref %s"), private);
			free(private);
		}
	}
	strbuf_release(&buf);
	return 0;
}
 
static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
{
	struct helper_data *data = transport->data;
	int ret = 0;
	int duped;
	FILE *input;
	struct child_process *helper;
 
	helper = get_helper(transport);
 
	/*
	 * Yes, dup the pipe another time, as we need unbuffered version
	 * of input pipe as FILE*. fclose() closes the underlying fd and
	 * stream buffering only can be changed before first I/O operation
	 * on it.
	 */
	duped = dup(helper->out);
	if (duped < 0)
		die_errno(_("can't dup helper output fd"));
	input = xfdopen(duped, "r");
	setvbuf(input, NULL, _IONBF, 0);
 
	sendline(data, cmdbuf);
	if (recvline_fh(input, cmdbuf))
		exit(128);
 
	if (!strcmp(cmdbuf->buf, "")) {
		data->no_disconnect_req = 1;
		if (debug)
			fprintf(stderr, "Debug: Smart transport connection "
				"ready.\n");
		ret = 1;
	} else if (!strcmp(cmdbuf->buf, "fallback")) {
		if (debug)
			fprintf(stderr, "Debug: Falling back to dumb "
				"transport.\n");
	} else {
		die(_("unknown response to connect: %s"),
		    cmdbuf->buf);
	}
 
	fclose(input);
	return ret;
}
 
static int process_connect_service(struct transport *transport,
				   const char *name, const char *exec)
{
	struct helper_data *data = transport->data;
	struct strbuf cmdbuf = STRBUF_INIT;
	int ret = 0;
 
	/*
	 * Handle --upload-pack and friends. This is fire and forget...
	 * just warn if it fails.
	 */
	if (strcmp(name, exec)) {
		int r = set_helper_option(transport, "servpath", exec);
		if (r > 0)
			warning(_("setting remote service path not supported by protocol"));
		else if (r < 0)
			warning(_("invalid remote service path"));
	}
 
	if (data->connect) {
		strbuf_addf(&cmdbuf, "connect %s\n", name);
		ret = run_connect(transport, &cmdbuf);
	} else if (data->stateless_connect &&
		   (get_protocol_version_config() == protocol_v2) &&
		   !strcmp("git-upload-pack", name)) {
		strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
		ret = run_connect(transport, &cmdbuf);
		if (ret)
			transport->stateless_rpc = 1;
	}
 
	strbuf_release(&cmdbuf);
	return ret;
}
 
static int process_connect(struct transport *transport,
				     int for_push)
{
	struct helper_data *data = transport->data;
	const char *name;
	const char *exec;
 
	name = for_push ? "git-receive-pack" : "git-upload-pack";
	if (for_push)
		exec = data->transport_options.receivepack;
	else
		exec = data->transport_options.uploadpack;
 
	return process_connect_service(transport, name, exec);
}
 
static int connect_helper(struct transport *transport, const char *name,
		   const char *exec, int fd[2])
{
	struct helper_data *data = transport->data;
 
	/* Get_helper so connect is inited. */
	get_helper(transport);
	if (!data->connect)
		die(_("operation not supported by protocol"));
 
	if (!process_connect_service(transport, name, exec))
		die(_("can't connect to subservice %s"), name);
 
	fd[0] = data->helper->out;
	fd[1] = data->helper->in;
	return 0;
}
 
static int fetch(struct transport *transport,
		 int nr_heads, struct ref **to_fetch)
{
	struct helper_data *data = transport->data;
	int i, count;
 
	if (process_connect(transport, 0)) {
		do_take_over(transport);
		return transport->vtable->fetch(transport, nr_heads, to_fetch);
	}
 
	count = 0;
	for (i = 0; i < nr_heads; i++)
		if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
			count++;
 
	if (!count)
		return 0;
 
	if (data->check_connectivity &&
	    data->transport_options.check_self_contained_and_connected)
		set_helper_option(transport, "check-connectivity", "true");
 
	if (transport->cloning)
		set_helper_option(transport, "cloning", "true");
 
	if (data->transport_options.update_shallow)
		set_helper_option(transport, "update-shallow", "true");
 
	if (data->transport_options.filter_options.choice)
		set_helper_option(
			transport, "filter",
			data->transport_options.filter_options.filter_spec);
 
	if (data->transport_options.negotiation_tips)
		warning("Ignoring --negotiation-tip because the protocol does not support it.");
 
	if (data->fetch)
		return fetch_with_fetch(transport, nr_heads, to_fetch);
 
	if (data->import)
		return fetch_with_import(transport, nr_heads, to_fetch);
 
	return -1;
}
 
static int push_update_ref_status(struct strbuf *buf,
				   struct ref **ref,
				   struct ref *remote_refs)
{
	char *refname, *msg;
	int status, forced = 0;
 
	if (starts_with(buf->buf, "ok ")) {
		status = REF_STATUS_OK;
		refname = buf->buf + 3;
	} else if (starts_with(buf->buf, "error ")) {
		status = REF_STATUS_REMOTE_REJECT;
		refname = buf->buf + 6;
	} else
		die(_("expected ok/error, helper said '%s'"), buf->buf);
 
	msg = strchr(refname, ' ');
	if (msg) {
		struct strbuf msg_buf = STRBUF_INIT;
		const char *end;
 
		*msg++ = '\0';
		if (!unquote_c_style(&msg_buf, msg, &end))
			msg = strbuf_detach(&msg_buf, NULL);
		else
			msg = xstrdup(msg);
		strbuf_release(&msg_buf);
 
		if (!strcmp(msg, "no match")) {
			status = REF_STATUS_NONE;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "up to date")) {
			status = REF_STATUS_UPTODATE;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "non-fast forward")) {
			status = REF_STATUS_REJECT_NONFASTFORWARD;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "already exists")) {
			status = REF_STATUS_REJECT_ALREADY_EXISTS;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "fetch first")) {
			status = REF_STATUS_REJECT_FETCH_FIRST;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "needs force")) {
			status = REF_STATUS_REJECT_NEEDS_FORCE;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "stale info")) {
			status = REF_STATUS_REJECT_STALE;
			FREE_AND_NULL(msg);
		}
		else if (!strcmp(msg, "forced update")) {
			forced = 1;
			FREE_AND_NULL(msg);
		}
	}
 
	if (*ref)
		*ref = find_ref_by_name(*ref, refname);
	if (!*ref)
		*ref = find_ref_by_name(remote_refs, refname);
	if (!*ref) {
		warning(_("helper reported unexpected status of %s"), refname);
		return 1;
	}
 
	if ((*ref)->status != REF_STATUS_NONE) {
		/*
		 * Earlier, the ref was marked not to be pushed, so ignore the ref
		 * status reported by the remote helper if the latter is 'no match'.
		 */
		if (status == REF_STATUS_NONE)
			return 1;
	}
 
	(*ref)->status = status;
	(*ref)->forced_update |= forced;
	(*ref)->remote_status = msg;
	return !(status == REF_STATUS_OK);
}
 
static int push_update_refs_status(struct helper_data *data,
				    struct ref *remote_refs,
				    int flags)
{
	struct strbuf buf = STRBUF_INIT;
	struct ref *ref = remote_refs;
	int ret = 0;
 
	for (;;) {
		char *private;
 
		if (recvline(data, &buf)) {
			ret = 1;
			break;
		}
 
		if (!buf.len)
			break;
 
		if (push_update_ref_status(&buf, &ref, remote_refs))
			continue;
 
		if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
			continue;
 
		/* propagate back the update to the remote namespace */
		private = apply_refspecs(&data->rs, ref->name);
		if (!private)
			continue;
		update_ref("update by helper", private, &ref->new_oid, NULL,
			   0, 0);
		free(private);
	}
	strbuf_release(&buf);
	return ret;
}
 
static void set_common_push_options(struct transport *transport,
				   const char *name, int flags)
{
	if (flags & TRANSPORT_PUSH_DRY_RUN) {
		if (set_helper_option(transport, "dry-run", "true") != 0)
			die(_("helper %s does not support dry-run"), name);
	} else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
		if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
			die(_("helper %s does not support --signed"), name);
	} else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
		if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
			die(_("helper %s does not support --signed=if-asked"), name);
	}
 
	if (flags & TRANSPORT_PUSH_OPTIONS) {
		struct string_list_item *item;
		for_each_string_list_item(item, transport->push_options)
			if (set_helper_option(transport, "push-option", item->string) != 0)
				die(_("helper %s does not support 'push-option'"), name);
	}
}
 
static int push_refs_with_push(struct transport *transport,
			       struct ref *remote_refs, int flags)
{
	int force_all = flags & TRANSPORT_PUSH_FORCE;
	int mirror = flags & TRANSPORT_PUSH_MIRROR;
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	struct ref *ref;
	struct string_list cas_options = STRING_LIST_INIT_DUP;
	struct string_list_item *cas_option;
 
	get_helper(transport);
	if (!data->push)
		return 1;
 
	for (ref = remote_refs; ref; ref = ref->next) {
		if (!ref->peer_ref && !mirror)
			continue;
 
		/* Check for statuses set by set_ref_status_for_push() */
		switch (ref->status) {
		case REF_STATUS_REJECT_NONFASTFORWARD:
		case REF_STATUS_REJECT_STALE:
		case REF_STATUS_REJECT_ALREADY_EXISTS:
		case REF_STATUS_UPTODATE:
			continue;
		default:
			; /* do nothing */
		}
 
		if (force_all)
			ref->force = 1;
 
		strbuf_addstr(&buf, "push ");
		if (!ref->deletion) {
			if (ref->force)
				strbuf_addch(&buf, '+');
			if (ref->peer_ref)
				strbuf_addstr(&buf, ref->peer_ref->name);
			else
				strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
		}
		strbuf_addch(&buf, ':');
		strbuf_addstr(&buf, ref->name);
		strbuf_addch(&buf, '\n');
 
		/*
		 * The "--force-with-lease" options without explicit
		 * values to expect have already been expanded into
		 * the ref->old_oid_expect[] field; we can ignore
		 * transport->smart_options->cas altogether and instead
		 * can enumerate them from the refs.
		 */
		if (ref->expect_old_sha1) {
			struct strbuf cas = STRBUF_INIT;
			strbuf_addf(&cas, "%s:%s",
				    ref->name, oid_to_hex(&ref->old_oid_expect));
			string_list_append_nodup(&cas_options,
						 strbuf_detach(&cas, NULL));
		}
	}
	if (buf.len == 0) {
		string_list_clear(&cas_options, 0);
		return 0;
	}
 
	for_each_string_list_item(cas_option, &cas_options)
		set_helper_option(transport, "cas", cas_option->string);
	set_common_push_options(transport, data->name, flags);
 
	strbuf_addch(&buf, '\n');
	sendline(data, &buf);
	strbuf_release(&buf);
	string_list_clear(&cas_options, 0);
 
	return push_update_refs_status(data, remote_refs, flags);
}
 
static int push_refs_with_export(struct transport *transport,
		struct ref *remote_refs, int flags)
{
	struct ref *ref;
	struct child_process *helper, exporter;
	struct helper_data *data = transport->data;
	struct string_list revlist_args = STRING_LIST_INIT_DUP;
	struct strbuf buf = STRBUF_INIT;
 
	if (!data->rs.nr)
		die(_("remote-helper doesn't support push; refspec needed"));
 
	set_common_push_options(transport, data->name, flags);
	if (flags & TRANSPORT_PUSH_FORCE) {
		if (set_helper_option(transport, "force", "true") != 0)
			warning(_("helper %s does not support 'force'"), data->name);
	}
 
	helper = get_helper(transport);
 
	write_constant(helper->in, "export\n");
 
	for (ref = remote_refs; ref; ref = ref->next) {
		char *private;
		struct object_id oid;
 
		private = apply_refspecs(&data->rs, ref->name);
		if (private && !get_oid(private, &oid)) {
			strbuf_addf(&buf, "^%s", private);
			string_list_append_nodup(&revlist_args,
						 strbuf_detach(&buf, NULL));
			oidcpy(&ref->old_oid, &oid);
		}
		free(private);
 
		if (ref->peer_ref) {
			if (strcmp(ref->name, ref->peer_ref->name)) {
				if (!ref->deletion) {
					const char *name;
					int flag;
 
					/* Follow symbolic refs (mainly for HEAD). */
					name = resolve_ref_unsafe(ref->peer_ref->name,
								  RESOLVE_REF_READING,
								  &oid, &flag);
					if (!name || !(flag & REF_ISSYMREF))
						name = ref->peer_ref->name;
 
					strbuf_addf(&buf, "%s:%s", name, ref->name);
				} else
					strbuf_addf(&buf, ":%s", ref->name);
 
				string_list_append(&revlist_args, "--refspec");
				string_list_append(&revlist_args, buf.buf);
				strbuf_release(&buf);
			}
			if (!ref->deletion)
				string_list_append(&revlist_args, ref->peer_ref->name);
		}
	}
 
	if (get_exporter(transport, &exporter, &revlist_args))
		die(_("couldn't run fast-export"));
 
	string_list_clear(&revlist_args, 1);
 
	if (finish_command(&exporter))
		die(_("error while running fast-export"));
	if (push_update_refs_status(data, remote_refs, flags))
		return 1;
 
	if (data->export_marks) {
		strbuf_addf(&buf, "%s.tmp", data->export_marks);
		rename(buf.buf, data->export_marks);
		strbuf_release(&buf);
	}
 
	return 0;
}
 
static int push_refs(struct transport *transport,
		struct ref *remote_refs, int flags)
{
	struct helper_data *data = transport->data;
 
	if (process_connect(transport, 1)) {
		do_take_over(transport);
		return transport->vtable->push_refs(transport, remote_refs, flags);
	}
 
	if (!remote_refs) {
		fprintf(stderr,
			_("No refs in common and none specified; doing nothing.\n"
			  "Perhaps you should specify a branch such as 'master'.\n"));
		return 0;
	}
 
	if (data->push)
		return push_refs_with_push(transport, remote_refs, flags);
 
	if (data->export)
		return push_refs_with_export(transport, remote_refs, flags);
 
	return -1;
}
 
 
static int has_attribute(const char *attrs, const char *attr) {
	int len;
	if (!attrs)
		return 0;
 
	len = strlen(attr);
	for (;;) {
		const char *space = strchrnul(attrs, ' ');
		if (len == space - attrs && !strncmp(attrs, attr, len))
			return 1;
		if (!*space)
			return 0;
		attrs = space + 1;
	}
}
 
static struct ref *get_refs_list(struct transport *transport, int for_push,
				 const struct argv_array *ref_prefixes)
{
	struct helper_data *data = transport->data;
	struct child_process *helper;
	struct ref *ret = NULL;
	struct ref **tail = &ret;
	struct ref *posn;
	struct strbuf buf = STRBUF_INIT;
 
	helper = get_helper(transport);
 
	if (process_connect(transport, for_push)) {
		do_take_over(transport);
		return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
	}
 
	if (data->push && for_push)
		write_str_in_full(helper->in, "list for-push\n");
	else
		write_str_in_full(helper->in, "list\n");
 
	while (1) {
		char *eov, *eon;
		if (recvline(data, &buf))
			exit(128);
 
		if (!*buf.buf)
			break;
 
		eov = strchr(buf.buf, ' ');
		if (!eov)
			die(_("malformed response in ref list: %s"), buf.buf);
		eon = strchr(eov + 1, ' ');
		*eov = '\0';
		if (eon)
			*eon = '\0';
		*tail = alloc_ref(eov + 1);
		if (buf.buf[0] == '@')
			(*tail)->symref = xstrdup(buf.buf + 1);
		else if (buf.buf[0] != '?')
			get_oid_hex(buf.buf, &(*tail)->old_oid);
		if (eon) {
			if (has_attribute(eon + 1, "unchanged")) {
				(*tail)->status |= REF_STATUS_UPTODATE;
				if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
					die(_("could not read ref %s"),
					    (*tail)->name);
			}
		}
		tail = &((*tail)->next);
	}
	if (debug)
		fprintf(stderr, "Debug: Read ref listing.\n");
	strbuf_release(&buf);
 
	for (posn = ret; posn; posn = posn->next)
		resolve_remote_symref(posn, ret);
 
	return ret;
}
 
static struct transport_vtable vtable = {
	0,
	set_helper_option,
	get_refs_list,
	fetch,
	push_refs,
	connect_helper,
	release_helper
};
 
int transport_helper_init(struct transport *transport, const char *name)
{
	struct helper_data *data = xcalloc(1, sizeof(*data));
	data->name = name;
 
	transport_check_allowed(name);
 
	if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
		debug = 1;
 
	transport->data = data;
	transport->vtable = &vtable;
	transport->smart_options = &(data->transport_options);
	return 0;
}
 
/*
 * Linux pipes can buffer 65536 bytes at once (and most platforms can
 * buffer less), so attempt reads and writes with up to that size.
 */
#define BUFFERSIZE 65536
/* This should be enough to hold debugging message. */
#define PBUFFERSIZE 8192
 
/* Print bidirectional transfer loop debug message. */
__attribute__((format (printf, 1, 2)))
static void transfer_debug(const char *fmt, ...)
{
	/*
	 * NEEDSWORK: This function is sometimes used from multiple threads, and
	 * we end up using debug_enabled racily. That "should not matter" since
	 * we always write the same value, but it's still wrong. This function
	 * is listed in .tsan-suppressions for the time being.
	 */
 
	va_list args;
	char msgbuf[PBUFFERSIZE];
	static int debug_enabled = -1;
 
	if (debug_enabled < 0)
		debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
	if (!debug_enabled)
		return;
 
	va_start(args, fmt);
	vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
	va_end(args);
	fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
}
 
/* Stream state: More data may be coming in this direction. */
#define SSTATE_TRANSFERRING 0
/*
 * Stream state: No more data coming in this direction, flushing rest of
 * data.
 */
#define SSTATE_FLUSHING 1
/* Stream state: Transfer in this direction finished. */
#define SSTATE_FINISHED 2
 
#define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
#define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
#define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 
/* Unidirectional transfer. */
struct unidirectional_transfer {
	/* Source */
	int src;
	/* Destination */
	int dest;
	/* Is source socket? */
	int src_is_sock;
	/* Is destination socket? */
	int dest_is_sock;
	/* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
	int state;
	/* Buffer. */
	char buf[BUFFERSIZE];
	/* Buffer used. */
	size_t bufuse;
	/* Name of source. */
	const char *src_name;
	/* Name of destination. */
	const char *dest_name;
};
 
/* Closes the target (for writing) if transfer has finished. */
static void udt_close_if_finished(struct unidirectional_transfer *t)
{
	if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
		t->state = SSTATE_FINISHED;
		if (t->dest_is_sock)
			shutdown(t->dest, SHUT_WR);
		else
			close(t->dest);
		transfer_debug("Closed %s.", t->dest_name);
	}
}
 
/*
 * Tries to read data from source into buffer. If buffer is full,
 * no data is read. Returns 0 on success, -1 on error.
 */
static int udt_do_read(struct unidirectional_transfer *t)
{
	ssize_t bytes;
 
	if (t->bufuse == BUFFERSIZE)
		return 0;	/* No space for more. */
 
	transfer_debug("%s is readable", t->src_name);
	bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
	if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
		errno != EINTR) {
		error_errno(_("read(%s) failed"), t->src_name);
		return -1;
	} else if (bytes == 0) {
		transfer_debug("%s EOF (with %i bytes in buffer)",
			t->src_name, (int)t->bufuse);
		t->state = SSTATE_FLUSHING;
	} else if (bytes > 0) {
		t->bufuse += bytes;
		transfer_debug("Read %i bytes from %s (buffer now at %i)",
			(int)bytes, t->src_name, (int)t->bufuse);
	}
	return 0;
}
 
/* Tries to write data from buffer into destination. If buffer is empty,
 * no data is written. Returns 0 on success, -1 on error.
 */
static int udt_do_write(struct unidirectional_transfer *t)
{
	ssize_t bytes;
 
	if (t->bufuse == 0)
		return 0;	/* Nothing to write. */
 
	transfer_debug("%s is writable", t->dest_name);
	bytes = xwrite(t->dest, t->buf, t->bufuse);
	if (bytes < 0 && errno != EWOULDBLOCK) {
		error_errno(_("write(%s) failed"), t->dest_name);
		return -1;
	} else if (bytes > 0) {
		t->bufuse -= bytes;
		if (t->bufuse)
			memmove(t->buf, t->buf + bytes, t->bufuse);
		transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
			(int)bytes, t->dest_name, (int)t->bufuse);
	}
	return 0;
}
 
 
/* State of bidirectional transfer loop. */
struct bidirectional_transfer_state {
	/* Direction from program to git. */
	struct unidirectional_transfer ptg;
	/* Direction from git to program. */
	struct unidirectional_transfer gtp;
};
 
static void *udt_copy_task_routine(void *udt)
{
	struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
	while (t->state != SSTATE_FINISHED) {
		if (STATE_NEEDS_READING(t->state))
			if (udt_do_read(t))
				return NULL;
		if (STATE_NEEDS_WRITING(t->state))
			if (udt_do_write(t))
				return NULL;
		if (STATE_NEEDS_CLOSING(t->state))
			udt_close_if_finished(t);
	}
	return udt;	/* Just some non-NULL value. */
}
 
#ifndef NO_PTHREADS
 
/*
 * Join thread, with appropriate errors on failure. Name is name for the
 * thread (for error messages). Returns 0 on success, 1 on failure.
 */
static int tloop_join(pthread_t thread, const char *name)
{
	int err;
	void *tret;
	err = pthread_join(thread, &tret);
	if (!tret) {
		error(_("%s thread failed"), name);
		return 1;
	}
	if (err) {
		error(_("%s thread failed to join: %s"), name, strerror(err));
		return 1;
	}
	return 0;
}
 
/*
 * Spawn the transfer tasks and then wait for them. Returns 0 on success,
 * -1 on failure.
 */
static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
{
	pthread_t gtp_thread;
	pthread_t ptg_thread;
	int err;
	int ret = 0;
	err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
		&s->gtp);
	if (err)
		die(_("can't start thread for copying data: %s"), strerror(err));
	err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
		&s->ptg);
	if (err)
		die(_("can't start thread for copying data: %s"), strerror(err));
 
	ret |= tloop_join(gtp_thread, "Git to program copy");
	ret |= tloop_join(ptg_thread, "Program to git copy");
	return ret;
}
#else
 
/* Close the source and target (for writing) for transfer. */
static void udt_kill_transfer(struct unidirectional_transfer *t)
{
	t->state = SSTATE_FINISHED;
	/*
	 * Socket read end left open isn't a disaster if nobody
	 * attempts to read from it (mingw compat headers do not
	 * have SHUT_RD)...
	 *
	 * We can't fully close the socket since otherwise gtp
	 * task would first close the socket it sends data to
	 * while closing the ptg file descriptors.
	 */
	if (!t->src_is_sock)
		close(t->src);
	if (t->dest_is_sock)
		shutdown(t->dest, SHUT_WR);
	else
		close(t->dest);
}
 
/*
 * Join process, with appropriate errors on failure. Name is name for the
 * process (for error messages). Returns 0 on success, 1 on failure.
 */
static int tloop_join(pid_t pid, const char *name)
{
	int tret;
	if (waitpid(pid, &tret, 0) < 0) {
		error_errno(_("%s process failed to wait"), name);
		return 1;
	}
	if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
		error(_("%s process failed"), name);
		return 1;
	}
	return 0;
}
 
/*
 * Spawn the transfer tasks and then wait for them. Returns 0 on success,
 * -1 on failure.
 */
static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
{
	pid_t pid1, pid2;
	int ret = 0;
 
	/* Fork thread #1: git to program. */
	pid1 = fork();
	if (pid1 < 0)
		die_errno(_("can't start thread for copying data"));
	else if (pid1 == 0) {
		udt_kill_transfer(&s->ptg);
		exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
	}
 
	/* Fork thread #2: program to git. */
	pid2 = fork();
	if (pid2 < 0)
		die_errno(_("can't start thread for copying data"));
	else if (pid2 == 0) {
		udt_kill_transfer(&s->gtp);
		exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
	}
 
	/*
	 * Close both streams in parent as to not interfere with
	 * end of file detection and wait for both tasks to finish.
	 */
	udt_kill_transfer(&s->gtp);
	udt_kill_transfer(&s->ptg);
	ret |= tloop_join(pid1, "Git to program copy");
	ret |= tloop_join(pid2, "Program to git copy");
	return ret;
}
#endif
 
/*
 * Copies data from stdin to output and from input to stdout simultaneously.
 * Additionally filtering through given filter. If filter is NULL, uses
 * identity filter.
 */
int bidirectional_transfer_loop(int input, int output)
{
	struct bidirectional_transfer_state state;
 
	/* Fill the state fields. */
	state.ptg.src = input;
	state.ptg.dest = 1;
	state.ptg.src_is_sock = (input == output);
	state.ptg.dest_is_sock = 0;
	state.ptg.state = SSTATE_TRANSFERRING;
	state.ptg.bufuse = 0;
	state.ptg.src_name = "remote input";
	state.ptg.dest_name = "stdout";
 
	state.gtp.src = 0;
	state.gtp.dest = output;
	state.gtp.src_is_sock = 0;
	state.gtp.dest_is_sock = (input == output);
	state.gtp.state = SSTATE_TRANSFERRING;
	state.gtp.bufuse = 0;
	state.gtp.src_name = "stdin";
	state.gtp.dest_name = "remote output";
 
	return tloop_spawnwait_tasks(&state);
}