summaryrefslogtreecommitdiff
path: root/remote-curl.c
blob: f48485931fc5e5ec9c17700801dd88d00ff40e01 (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
#include "cache.h"
#include "remote.h"
#include "strbuf.h"
#include "walker.h"
#include "http.h"
#include "exec_cmd.h"
#include "run-command.h"
#include "pkt-line.h"
#include "sideband.h"

static struct remote *remote;
static const char *url; /* always ends with a trailing slash */

struct options {
	int verbosity;
	unsigned long depth;
	unsigned progress : 1,
		followtags : 1,
		dry_run : 1,
		thin : 1;
};
static struct options options;

static int set_option(const char *name, const char *value)
{
	if (!strcmp(name, "verbosity")) {
		char *end;
		int v = strtol(value, &end, 10);
		if (value == end || *end)
			return -1;
		options.verbosity = v;
		return 0;
	}
	else if (!strcmp(name, "progress")) {
		if (!strcmp(value, "true"))
			options.progress = 1;
		else if (!strcmp(value, "false"))
			options.progress = 0;
		else
			return -1;
		return 0;
	}
	else if (!strcmp(name, "depth")) {
		char *end;
		unsigned long v = strtoul(value, &end, 10);
		if (value == end || *end)
			return -1;
		options.depth = v;
		return 0;
	}
	else if (!strcmp(name, "followtags")) {
		if (!strcmp(value, "true"))
			options.followtags = 1;
		else if (!strcmp(value, "false"))
			options.followtags = 0;
		else
			return -1;
		return 0;
	}
	else if (!strcmp(name, "dry-run")) {
		if (!strcmp(value, "true"))
			options.dry_run = 1;
		else if (!strcmp(value, "false"))
			options.dry_run = 0;
		else
			return -1;
		return 0;
	}
	else {
		return 1 /* unsupported */;
	}
}

struct discovery {
	const char *service;
	char *buf_alloc;
	char *buf;
	size_t len;
	unsigned proto_git : 1;
};
static struct discovery *last_discovery;

static void free_discovery(struct discovery *d)
{
	if (d) {
		if (d == last_discovery)
			last_discovery = NULL;
		free(d->buf_alloc);
		free(d);
	}
}

static struct discovery* discover_refs(const char *service)
{
	struct strbuf buffer = STRBUF_INIT;
	struct discovery *last = last_discovery;
	char *refs_url;
	int http_ret, is_http = 0, proto_git_candidate = 1;

	if (last && !strcmp(service, last->service))
		return last;
	free_discovery(last);

	strbuf_addf(&buffer, "%sinfo/refs", url);
	if (!prefixcmp(url, "http://") || !prefixcmp(url, "https://")) {
		is_http = 1;
		if (!strchr(url, '?'))
			strbuf_addch(&buffer, '?');
		else
			strbuf_addch(&buffer, '&');
		strbuf_addf(&buffer, "service=%s", service);
	}
	refs_url = strbuf_detach(&buffer, NULL);

	http_ret = http_get_strbuf(refs_url, &buffer, HTTP_NO_CACHE);

	/* try again with "plain" url (no ? or & appended) */
	if (http_ret != HTTP_OK) {
		free(refs_url);
		strbuf_reset(&buffer);

		proto_git_candidate = 0;
		strbuf_addf(&buffer, "%sinfo/refs", url);
		refs_url = strbuf_detach(&buffer, NULL);

		http_ret = http_get_strbuf(refs_url, &buffer, HTTP_NO_CACHE);
	}

	switch (http_ret) {
	case HTTP_OK:
		break;
	case HTTP_MISSING_TARGET:
		die("%s not found: did you run git update-server-info on the"
		    " server?", refs_url);
	case HTTP_NOAUTH:
		die("Authentication failed");
	default:
		http_error(refs_url, http_ret);
		die("HTTP request failed");
	}

	last= xcalloc(1, sizeof(*last_discovery));
	last->service = service;
	last->buf_alloc = strbuf_detach(&buffer, &last->len);
	last->buf = last->buf_alloc;

	if (is_http && proto_git_candidate
		&& 5 <= last->len && last->buf[4] == '#') {
		/* smart HTTP response; validate that the service
		 * pkt-line matches our request.
		 */
		struct strbuf exp = STRBUF_INIT;

		if (packet_get_line(&buffer, &last->buf, &last->len) <= 0)
			die("%s has invalid packet header", refs_url);
		if (buffer.len && buffer.buf[buffer.len - 1] == '\n')
			strbuf_setlen(&buffer, buffer.len - 1);

		strbuf_addf(&exp, "# service=%s", service);
		if (strbuf_cmp(&exp, &buffer))
			die("invalid server response; got '%s'", buffer.buf);
		strbuf_release(&exp);

		/* The header can include additional metadata lines, up
		 * until a packet flush marker.  Ignore these now, but
		 * in the future we might start to scan them.
		 */
		strbuf_reset(&buffer);
		while (packet_get_line(&buffer, &last->buf, &last->len) > 0)
			strbuf_reset(&buffer);

		last->proto_git = 1;
	}

	free(refs_url);
	strbuf_release(&buffer);
	last_discovery = last;
	return last;
}

static int write_discovery(int in, int out, void *data)
{
	struct discovery *heads = data;
	int err = 0;
	if (write_in_full(out, heads->buf, heads->len) != heads->len)
		err = 1;
	close(out);
	return err;
}

static struct ref *parse_git_refs(struct discovery *heads)
{
	struct ref *list = NULL;
	struct async async;

	memset(&async, 0, sizeof(async));
	async.proc = write_discovery;
	async.data = heads;
	async.out = -1;

	if (start_async(&async))
		die("cannot start thread to parse advertised refs");
	get_remote_heads(async.out, &list, 0, NULL, 0, NULL);
	close(async.out);
	if (finish_async(&async))
		die("ref parsing thread failed");
	return list;
}

static struct ref *parse_info_refs(struct discovery *heads)
{
	char *data, *start, *mid;
	char *ref_name;
	int i = 0;

	struct ref *refs = NULL;
	struct ref *ref = NULL;
	struct ref *last_ref = NULL;

	data = heads->buf;
	start = NULL;
	mid = data;
	while (i < heads->len) {
		if (!start) {
			start = &data[i];
		}
		if (data[i] == '\t')
			mid = &data[i];
		if (data[i] == '\n') {
			if (mid - start != 40)
				die("%sinfo/refs not valid: is this a git repository?", url);
			data[i] = 0;
			ref_name = mid + 1;
			ref = xmalloc(sizeof(struct ref) +
				      strlen(ref_name) + 1);
			memset(ref, 0, sizeof(struct ref));
			strcpy(ref->name, ref_name);
			get_sha1_hex(start, ref->old_sha1);
			if (!refs)
				refs = ref;
			if (last_ref)
				last_ref->next = ref;
			last_ref = ref;
			start = NULL;
		}
		i++;
	}

	ref = alloc_ref("HEAD");
	if (!http_fetch_ref(url, ref) &&
	    !resolve_remote_symref(ref, refs)) {
		ref->next = refs;
		refs = ref;
	} else {
		free(ref);
	}

	return refs;
}

static struct ref *get_refs(int for_push)
{
	struct discovery *heads;

	if (for_push)
		heads = discover_refs("git-receive-pack");
	else
		heads = discover_refs("git-upload-pack");

	if (heads->proto_git)
		return parse_git_refs(heads);
	return parse_info_refs(heads);
}

static void output_refs(struct ref *refs)
{
	struct ref *posn;
	for (posn = refs; posn; posn = posn->next) {
		if (posn->symref)
			printf("@%s %s\n", posn->symref, posn->name);
		else
			printf("%s %s\n", sha1_to_hex(posn->old_sha1), posn->name);
	}
	printf("\n");
	fflush(stdout);
	free_refs(refs);
}

struct rpc_state {
	const char *service_name;
	const char **argv;
	char *service_url;
	char *hdr_content_type;
	char *hdr_accept;
	char *buf;
	size_t alloc;
	size_t len;
	size_t pos;
	int in;
	int out;
	struct strbuf result;
	unsigned gzip_request : 1;
	unsigned initial_buffer : 1;
};

static size_t rpc_out(void *ptr, size_t eltsize,
		size_t nmemb, void *buffer_)
{
	size_t max = eltsize * nmemb;
	struct rpc_state *rpc = buffer_;
	size_t avail = rpc->len - rpc->pos;

	if (!avail) {
		rpc->initial_buffer = 0;
		avail = packet_read_line(rpc->out, rpc->buf, rpc->alloc);
		if (!avail)
			return 0;
		rpc->pos = 0;
		rpc->len = avail;
	}

	if (max < avail)
		avail = max;
	memcpy(ptr, rpc->buf + rpc->pos, avail);
	rpc->pos += avail;
	return avail;
}

#ifndef NO_CURL_IOCTL
static curlioerr rpc_ioctl(CURL *handle, int cmd, void *clientp)
{
	struct rpc_state *rpc = clientp;

	switch (cmd) {
	case CURLIOCMD_NOP:
		return CURLIOE_OK;

	case CURLIOCMD_RESTARTREAD:
		if (rpc->initial_buffer) {
			rpc->pos = 0;
			return CURLIOE_OK;
		}
		fprintf(stderr, "Unable to rewind rpc post data - try increasing http.postBuffer\n");
		return CURLIOE_FAILRESTART;

	default:
		return CURLIOE_UNKNOWNCMD;
	}
}
#endif

static size_t rpc_in(char *ptr, size_t eltsize,
		size_t nmemb, void *buffer_)
{
	size_t size = eltsize * nmemb;
	struct rpc_state *rpc = buffer_;
	write_or_die(rpc->in, ptr, size);
	return size;
}

static int run_slot(struct active_request_slot *slot)
{
	int err = 0;
	struct slot_results results;

	slot->results = &results;
	slot->curl_result = curl_easy_perform(slot->curl);
	finish_active_slot(slot);

	if (results.curl_result != CURLE_OK) {
		err |= error("RPC failed; result=%d, HTTP code = %ld",
			results.curl_result, results.http_code);
	}

	return err;
}

static int probe_rpc(struct rpc_state *rpc)
{
	struct active_request_slot *slot;
	struct curl_slist *headers = NULL;
	struct strbuf buf = STRBUF_INIT;
	int err;

	slot = get_active_slot();

	headers = curl_slist_append(headers, rpc->hdr_content_type);
	headers = curl_slist_append(headers, rpc->hdr_accept);

	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
	curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
	curl_easy_setopt(slot->curl, CURLOPT_URL, rpc->service_url);
	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "");
	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, "0000");
	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, 4);
	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
	curl_easy_setopt(slot->curl, CURLOPT_FILE, &buf);

	err = run_slot(slot);

	curl_slist_free_all(headers);
	strbuf_release(&buf);
	return err;
}

static int post_rpc(struct rpc_state *rpc)
{
	struct active_request_slot *slot;
	struct curl_slist *headers = NULL;
	int use_gzip = rpc->gzip_request;
	char *gzip_body = NULL;
	int err, large_request = 0;

	/* Try to load the entire request, if we can fit it into the
	 * allocated buffer space we can use HTTP/1.0 and avoid the
	 * chunked encoding mess.
	 */
	while (1) {
		size_t left = rpc->alloc - rpc->len;
		char *buf = rpc->buf + rpc->len;
		int n;

		if (left < LARGE_PACKET_MAX) {
			large_request = 1;
			use_gzip = 0;
			break;
		}

		n = packet_read_line(rpc->out, buf, left);
		if (!n)
			break;
		rpc->len += n;
	}

	if (large_request) {
		err = probe_rpc(rpc);
		if (err)
			return err;
	}

	slot = get_active_slot();

	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
	curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
	curl_easy_setopt(slot->curl, CURLOPT_URL, rpc->service_url);
	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "");

	headers = curl_slist_append(headers, rpc->hdr_content_type);
	headers = curl_slist_append(headers, rpc->hdr_accept);
	headers = curl_slist_append(headers, "Expect:");

	if (large_request) {
		/* The request body is large and the size cannot be predicted.
		 * We must use chunked encoding to send it.
		 */
		headers = curl_slist_append(headers, "Transfer-Encoding: chunked");
		rpc->initial_buffer = 1;
		curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, rpc_out);
		curl_easy_setopt(slot->curl, CURLOPT_INFILE, rpc);
#ifndef NO_CURL_IOCTL
		curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, rpc_ioctl);
		curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, rpc);
#endif
		if (options.verbosity > 1) {
			fprintf(stderr, "POST %s (chunked)\n", rpc->service_name);
			fflush(stderr);
		}

	} else if (use_gzip && 1024 < rpc->len) {
		/* The client backend isn't giving us compressed data so
		 * we can try to deflate it ourselves, this may save on.
		 * the transfer time.
		 */
		size_t size;
		git_zstream stream;
		int ret;

		memset(&stream, 0, sizeof(stream));
		git_deflate_init_gzip(&stream, Z_BEST_COMPRESSION);
		size = git_deflate_bound(&stream, rpc->len);
		gzip_body = xmalloc(size);

		stream.next_in = (unsigned char *)rpc->buf;
		stream.avail_in = rpc->len;
		stream.next_out = (unsigned char *)gzip_body;
		stream.avail_out = size;

		ret = git_deflate(&stream, Z_FINISH);
		if (ret != Z_STREAM_END)
			die("cannot deflate request; zlib deflate error %d", ret);

		ret = git_deflate_end_gently(&stream);
		if (ret != Z_OK)
			die("cannot deflate request; zlib end error %d", ret);

		size = stream.total_out;

		headers = curl_slist_append(headers, "Content-Encoding: gzip");
		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, gzip_body);
		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, size);

		if (options.verbosity > 1) {
			fprintf(stderr, "POST %s (gzip %lu to %lu bytes)\n",
				rpc->service_name,
				(unsigned long)rpc->len, (unsigned long)size);
			fflush(stderr);
		}
	} else {
		/* We know the complete request size in advance, use the
		 * more normal Content-Length approach.
		 */
		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, rpc->buf);
		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, rpc->len);
		if (options.verbosity > 1) {
			fprintf(stderr, "POST %s (%lu bytes)\n",
				rpc->service_name, (unsigned long)rpc->len);
			fflush(stderr);
		}
	}

	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, rpc_in);
	curl_easy_setopt(slot->curl, CURLOPT_FILE, rpc);

	err = run_slot(slot);

	curl_slist_free_all(headers);
	free(gzip_body);
	return err;
}

static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
{
	const char *svc = rpc->service_name;
	struct strbuf buf = STRBUF_INIT;
	struct child_process client;
	int err = 0;

	memset(&client, 0, sizeof(client));
	client.in = -1;
	client.out = -1;
	client.git_cmd = 1;
	client.argv = rpc->argv;
	if (start_command(&client))
		exit(1);
	if (heads)
		write_or_die(client.in, heads->buf, heads->len);

	rpc->alloc = http_post_buffer;
	rpc->buf = xmalloc(rpc->alloc);
	rpc->in = client.in;
	rpc->out = client.out;
	strbuf_init(&rpc->result, 0);

	strbuf_addf(&buf, "%s%s", url, svc);
	rpc->service_url = strbuf_detach(&buf, NULL);

	strbuf_addf(&buf, "Content-Type: application/x-%s-request", svc);
	rpc->hdr_content_type = strbuf_detach(&buf, NULL);

	strbuf_addf(&buf, "Accept: application/x-%s-result", svc);
	rpc->hdr_accept = strbuf_detach(&buf, NULL);

	while (!err) {
		int n = packet_read_line(rpc->out, rpc->buf, rpc->alloc);
		if (!n)
			break;
		rpc->pos = 0;
		rpc->len = n;
		err |= post_rpc(rpc);
	}

	close(client.in);
	client.in = -1;
	strbuf_read(&rpc->result, client.out, 0);

	close(client.out);
	client.out = -1;

	err |= finish_command(&client);
	free(rpc->service_url);
	free(rpc->hdr_content_type);
	free(rpc->hdr_accept);
	free(rpc->buf);
	strbuf_release(&buf);
	return err;
}

static int fetch_dumb(int nr_heads, struct ref **to_fetch)
{
	struct walker *walker;
	char **targets = xmalloc(nr_heads * sizeof(char*));
	int ret, i;

	if (options.depth)
		die("dumb http transport does not support --depth");
	for (i = 0; i < nr_heads; i++)
		targets[i] = xstrdup(sha1_to_hex(to_fetch[i]->old_sha1));

	walker = get_http_walker(url);
	walker->get_all = 1;
	walker->get_tree = 1;
	walker->get_history = 1;
	walker->get_verbosely = options.verbosity >= 3;
	walker->get_recover = 0;
	ret = walker_fetch(walker, nr_heads, targets, NULL, NULL);
	walker_free(walker);

	for (i = 0; i < nr_heads; i++)
		free(targets[i]);
	free(targets);

	return ret ? error("Fetch failed.") : 0;
}

static int fetch_git(struct discovery *heads,
	int nr_heads, struct ref **to_fetch)
{
	struct rpc_state rpc;
	char *depth_arg = NULL;
	const char **argv;
	int argc = 0, i, err;

	argv = xmalloc((15 + nr_heads) * sizeof(char*));
	argv[argc++] = "fetch-pack";
	argv[argc++] = "--stateless-rpc";
	argv[argc++] = "--lock-pack";
	if (options.followtags)
		argv[argc++] = "--include-tag";
	if (options.thin)
		argv[argc++] = "--thin";
	if (options.verbosity >= 3) {
		argv[argc++] = "-v";
		argv[argc++] = "-v";
	}
	if (!options.progress)
		argv[argc++] = "--no-progress";
	if (options.depth) {
		struct strbuf buf = STRBUF_INIT;
		strbuf_addf(&buf, "--depth=%lu", options.depth);
		depth_arg = strbuf_detach(&buf, NULL);
		argv[argc++] = depth_arg;
	}
	argv[argc++] = url;
	for (i = 0; i < nr_heads; i++) {
		struct ref *ref = to_fetch[i];
		if (!ref->name || !*ref->name)
			die("cannot fetch by sha1 over smart http");
		argv[argc++] = ref->name;
	}
	argv[argc++] = NULL;

	memset(&rpc, 0, sizeof(rpc));
	rpc.service_name = "git-upload-pack",
	rpc.argv = argv;
	rpc.gzip_request = 1;

	err = rpc_service(&rpc, heads);
	if (rpc.result.len)
		safe_write(1, rpc.result.buf, rpc.result.len);
	strbuf_release(&rpc.result);
	free(argv);
	free(depth_arg);
	return err;
}

static int fetch(int nr_heads, struct ref **to_fetch)
{
	struct discovery *d = discover_refs("git-upload-pack");
	if (d->proto_git)
		return fetch_git(d, nr_heads, to_fetch);
	else
		return fetch_dumb(nr_heads, to_fetch);
}

static void parse_fetch(struct strbuf *buf)
{
	struct ref **to_fetch = NULL;
	struct ref *list_head = NULL;
	struct ref **list = &list_head;
	int alloc_heads = 0, nr_heads = 0;

	do {
		if (!prefixcmp(buf->buf, "fetch ")) {
			char *p = buf->buf + strlen("fetch ");
			char *name;
			struct ref *ref;
			unsigned char old_sha1[20];

			if (strlen(p) < 40 || get_sha1_hex(p, old_sha1))
				die("protocol error: expected sha/ref, got %s'", p);
			if (p[40] == ' ')
				name = p + 41;
			else if (!p[40])
				name = "";
			else
				die("protocol error: expected sha/ref, got %s'", p);

			ref = alloc_ref(name);
			hashcpy(ref->old_sha1, old_sha1);

			*list = ref;
			list = &ref->next;

			ALLOC_GROW(to_fetch, nr_heads + 1, alloc_heads);
			to_fetch[nr_heads++] = ref;
		}
		else
			die("http transport does not support %s", buf->buf);

		strbuf_reset(buf);
		if (strbuf_getline(buf, stdin, '\n') == EOF)
			return;
		if (!*buf->buf)
			break;
	} while (1);

	if (fetch(nr_heads, to_fetch))
		exit(128); /* error already reported */
	free_refs(list_head);
	free(to_fetch);

	printf("\n");
	fflush(stdout);
	strbuf_reset(buf);
}

static int push_dav(int nr_spec, char **specs)
{
	const char **argv = xmalloc((10 + nr_spec) * sizeof(char*));
	int argc = 0, i;

	argv[argc++] = "http-push";
	argv[argc++] = "--helper-status";
	if (options.dry_run)
		argv[argc++] = "--dry-run";
	if (options.verbosity > 1)
		argv[argc++] = "--verbose";
	argv[argc++] = url;
	for (i = 0; i < nr_spec; i++)
		argv[argc++] = specs[i];
	argv[argc++] = NULL;

	if (run_command_v_opt(argv, RUN_GIT_CMD))
		die("git-%s failed", argv[0]);
	free(argv);
	return 0;
}

static int push_git(struct discovery *heads, int nr_spec, char **specs)
{
	struct rpc_state rpc;
	const char **argv;
	int argc = 0, i, err;

	argv = xmalloc((10 + nr_spec) * sizeof(char*));
	argv[argc++] = "send-pack";
	argv[argc++] = "--stateless-rpc";
	argv[argc++] = "--helper-status";
	if (options.thin)
		argv[argc++] = "--thin";
	if (options.dry_run)
		argv[argc++] = "--dry-run";
	if (options.verbosity > 1)
		argv[argc++] = "--verbose";
	argv[argc++] = url;
	for (i = 0; i < nr_spec; i++)
		argv[argc++] = specs[i];
	argv[argc++] = NULL;

	memset(&rpc, 0, sizeof(rpc));
	rpc.service_name = "git-receive-pack",
	rpc.argv = argv;

	err = rpc_service(&rpc, heads);
	if (rpc.result.len)
		safe_write(1, rpc.result.buf, rpc.result.len);
	strbuf_release(&rpc.result);
	free(argv);
	return err;
}

static int push(int nr_spec, char **specs)
{
	struct discovery *heads = discover_refs("git-receive-pack");
	int ret;

	if (heads->proto_git)
		ret = push_git(heads, nr_spec, specs);
	else
		ret = push_dav(nr_spec, specs);
	free_discovery(heads);
	return ret;
}

static void parse_push(struct strbuf *buf)
{
	char **specs = NULL;
	int alloc_spec = 0, nr_spec = 0, i, ret;

	do {
		if (!prefixcmp(buf->buf, "push ")) {
			ALLOC_GROW(specs, nr_spec + 1, alloc_spec);
			specs[nr_spec++] = xstrdup(buf->buf + 5);
		}
		else
			die("http transport does not support %s", buf->buf);

		strbuf_reset(buf);
		if (strbuf_getline(buf, stdin, '\n') == EOF)
			goto free_specs;
		if (!*buf->buf)
			break;
	} while (1);

	ret = push(nr_spec, specs);
	printf("\n");
	fflush(stdout);

	if (ret)
		exit(128); /* error already reported */

 free_specs:
	for (i = 0; i < nr_spec; i++)
		free(specs[i]);
	free(specs);
}

int main(int argc, const char **argv)
{
	struct strbuf buf = STRBUF_INIT;
	int nongit;

	git_extract_argv0_path(argv[0]);
	setup_git_directory_gently(&nongit);
	if (argc < 2) {
		fprintf(stderr, "Remote needed\n");
		return 1;
	}

	options.verbosity = 1;
	options.progress = !!isatty(2);
	options.thin = 1;

	remote = remote_get(argv[1]);

	if (argc > 2) {
		end_url_with_slash(&buf, argv[2]);
	} else {
		end_url_with_slash(&buf, remote->url[0]);
	}

	url = strbuf_detach(&buf, NULL);

	http_init(remote);

	do {
		if (strbuf_getline(&buf, stdin, '\n') == EOF)
			break;
		if (!prefixcmp(buf.buf, "fetch ")) {
			if (nongit)
				die("Fetch attempted without a local repo");
			parse_fetch(&buf);

		} else if (!strcmp(buf.buf, "list") || !prefixcmp(buf.buf, "list ")) {
			int for_push = !!strstr(buf.buf + 4, "for-push");
			output_refs(get_refs(for_push));

		} else if (!prefixcmp(buf.buf, "push ")) {
			parse_push(&buf);

		} else if (!prefixcmp(buf.buf, "option ")) {
			char *name = buf.buf + strlen("option ");
			char *value = strchr(name, ' ');
			int result;

			if (value)
				*value++ = '\0';
			else
				value = "true";

			result = set_option(name, value);
			if (!result)
				printf("ok\n");
			else if (result < 0)
				printf("error invalid value\n");
			else
				printf("unsupported\n");
			fflush(stdout);

		} else if (!strcmp(buf.buf, "capabilities")) {
			printf("fetch\n");
			printf("option\n");
			printf("push\n");
			printf("\n");
			fflush(stdout);
		} else {
			return 1;
		}
		strbuf_reset(&buf);
	} while (1);

	http_cleanup();

	return 0;
}