Merge branch 'rt/format-zero-length-fix'
[git] / transport-helper.c
1 #include "cache.h"
2 #include "transport.h"
3 #include "quote.h"
4 #include "run-command.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "revision.h"
8 #include "remote.h"
9 #include "string-list.h"
10 #include "thread-utils.h"
11 #include "sigchain.h"
12 #include "argv-array.h"
13 #include "refs.h"
14 #include "refspec.h"
15 #include "transport-internal.h"
16 #include "protocol.h"
17
18 static int debug;
19
20 struct helper_data {
21         const char *name;
22         struct child_process *helper;
23         FILE *out;
24         unsigned fetch : 1,
25                 import : 1,
26                 bidi_import : 1,
27                 export : 1,
28                 option : 1,
29                 push : 1,
30                 connect : 1,
31                 stateless_connect : 1,
32                 signed_tags : 1,
33                 check_connectivity : 1,
34                 no_disconnect_req : 1,
35                 no_private_update : 1;
36
37         /*
38          * As an optimization, the transport code may invoke fetch before
39          * get_refs_list. If this happens, and if the transport helper doesn't
40          * support connect or stateless_connect, we need to invoke
41          * get_refs_list ourselves if we haven't already done so. Keep track of
42          * whether we have invoked get_refs_list.
43          */
44         unsigned get_refs_list_called : 1;
45
46         char *export_marks;
47         char *import_marks;
48         /* These go from remote name (as in "list") to private name */
49         struct refspec rs;
50         /* Transport options for fetch-pack/send-pack (should one of
51          * those be invoked).
52          */
53         struct git_transport_options transport_options;
54 };
55
56 static void sendline(struct helper_data *helper, struct strbuf *buffer)
57 {
58         if (debug)
59                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
60         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
61                 die_errno(_("full write to remote helper failed"));
62 }
63
64 static int recvline_fh(FILE *helper, struct strbuf *buffer)
65 {
66         strbuf_reset(buffer);
67         if (debug)
68                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
69         if (strbuf_getline(buffer, helper) == EOF) {
70                 if (debug)
71                         fprintf(stderr, "Debug: Remote helper quit.\n");
72                 return 1;
73         }
74
75         if (debug)
76                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
77         return 0;
78 }
79
80 static int recvline(struct helper_data *helper, struct strbuf *buffer)
81 {
82         return recvline_fh(helper->out, buffer);
83 }
84
85 static void write_constant(int fd, const char *str)
86 {
87         if (debug)
88                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
89         if (write_in_full(fd, str, strlen(str)) < 0)
90                 die_errno(_("full write to remote helper failed"));
91 }
92
93 static const char *remove_ext_force(const char *url)
94 {
95         if (url) {
96                 const char *colon = strchr(url, ':');
97                 if (colon && colon[1] == ':')
98                         return colon + 2;
99         }
100         return url;
101 }
102
103 static void do_take_over(struct transport *transport)
104 {
105         struct helper_data *data;
106         data = (struct helper_data *)transport->data;
107         transport_take_over(transport, data->helper);
108         fclose(data->out);
109         free(data);
110 }
111
112 static void standard_options(struct transport *t);
113
114 static struct child_process *get_helper(struct transport *transport)
115 {
116         struct helper_data *data = transport->data;
117         struct strbuf buf = STRBUF_INIT;
118         struct child_process *helper;
119         int duped;
120         int code;
121
122         if (data->helper)
123                 return data->helper;
124
125         helper = xmalloc(sizeof(*helper));
126         child_process_init(helper);
127         helper->in = -1;
128         helper->out = -1;
129         helper->err = 0;
130         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
131         argv_array_push(&helper->args, transport->remote->name);
132         argv_array_push(&helper->args, remove_ext_force(transport->url));
133         helper->git_cmd = 0;
134         helper->silent_exec_failure = 1;
135
136         if (have_git_dir())
137                 argv_array_pushf(&helper->env_array, "%s=%s",
138                                  GIT_DIR_ENVIRONMENT, get_git_dir());
139
140         helper->trace2_child_class = helper->args.argv[0]; /* "remote-<name>" */
141
142         code = start_command(helper);
143         if (code < 0 && errno == ENOENT)
144                 die(_("unable to find remote helper for '%s'"), data->name);
145         else if (code != 0)
146                 exit(code);
147
148         data->helper = helper;
149         data->no_disconnect_req = 0;
150         refspec_init(&data->rs, REFSPEC_FETCH);
151
152         /*
153          * Open the output as FILE* so strbuf_getline_*() family of
154          * functions can be used.
155          * Do this with duped fd because fclose() will close the fd,
156          * and stuff like taking over will require the fd to remain.
157          */
158         duped = dup(helper->out);
159         if (duped < 0)
160                 die_errno(_("can't dup helper output fd"));
161         data->out = xfdopen(duped, "r");
162
163         write_constant(helper->in, "capabilities\n");
164
165         while (1) {
166                 const char *capname, *arg;
167                 int mandatory = 0;
168                 if (recvline(data, &buf))
169                         exit(128);
170
171                 if (!*buf.buf)
172                         break;
173
174                 if (*buf.buf == '*') {
175                         capname = buf.buf + 1;
176                         mandatory = 1;
177                 } else
178                         capname = buf.buf;
179
180                 if (debug)
181                         fprintf(stderr, "Debug: Got cap %s\n", capname);
182                 if (!strcmp(capname, "fetch"))
183                         data->fetch = 1;
184                 else if (!strcmp(capname, "option"))
185                         data->option = 1;
186                 else if (!strcmp(capname, "push"))
187                         data->push = 1;
188                 else if (!strcmp(capname, "import"))
189                         data->import = 1;
190                 else if (!strcmp(capname, "bidi-import"))
191                         data->bidi_import = 1;
192                 else if (!strcmp(capname, "export"))
193                         data->export = 1;
194                 else if (!strcmp(capname, "check-connectivity"))
195                         data->check_connectivity = 1;
196                 else if (skip_prefix(capname, "refspec ", &arg)) {
197                         refspec_append(&data->rs, arg);
198                 } else if (!strcmp(capname, "connect")) {
199                         data->connect = 1;
200                 } else if (!strcmp(capname, "stateless-connect")) {
201                         data->stateless_connect = 1;
202                 } else if (!strcmp(capname, "signed-tags")) {
203                         data->signed_tags = 1;
204                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
205                         data->export_marks = xstrdup(arg);
206                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
207                         data->import_marks = xstrdup(arg);
208                 } else if (starts_with(capname, "no-private-update")) {
209                         data->no_private_update = 1;
210                 } else if (mandatory) {
211                         die(_("unknown mandatory capability %s; this remote "
212                               "helper probably needs newer version of Git"),
213                             capname);
214                 }
215         }
216         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
217                 warning(_("this remote helper should implement refspec capability"));
218         }
219         strbuf_release(&buf);
220         if (debug)
221                 fprintf(stderr, "Debug: Capabilities complete.\n");
222         standard_options(transport);
223         return data->helper;
224 }
225
226 static int disconnect_helper(struct transport *transport)
227 {
228         struct helper_data *data = transport->data;
229         int res = 0;
230
231         if (data->helper) {
232                 if (debug)
233                         fprintf(stderr, "Debug: Disconnecting.\n");
234                 if (!data->no_disconnect_req) {
235                         /*
236                          * Ignore write errors; there's nothing we can do,
237                          * since we're about to close the pipe anyway. And the
238                          * most likely error is EPIPE due to the helper dying
239                          * to report an error itself.
240                          */
241                         sigchain_push(SIGPIPE, SIG_IGN);
242                         xwrite(data->helper->in, "\n", 1);
243                         sigchain_pop(SIGPIPE);
244                 }
245                 close(data->helper->in);
246                 close(data->helper->out);
247                 fclose(data->out);
248                 res = finish_command(data->helper);
249                 FREE_AND_NULL(data->helper);
250         }
251         return res;
252 }
253
254 static const char *unsupported_options[] = {
255         TRANS_OPT_UPLOADPACK,
256         TRANS_OPT_RECEIVEPACK,
257         TRANS_OPT_THIN,
258         TRANS_OPT_KEEP
259         };
260
261 static const char *boolean_options[] = {
262         TRANS_OPT_THIN,
263         TRANS_OPT_KEEP,
264         TRANS_OPT_FOLLOWTAGS,
265         TRANS_OPT_DEEPEN_RELATIVE
266         };
267
268 static int strbuf_set_helper_option(struct helper_data *data,
269                                     struct strbuf *buf)
270 {
271         int ret;
272
273         sendline(data, buf);
274         if (recvline(data, buf))
275                 exit(128);
276
277         if (!strcmp(buf->buf, "ok"))
278                 ret = 0;
279         else if (starts_with(buf->buf, "error"))
280                 ret = -1;
281         else if (!strcmp(buf->buf, "unsupported"))
282                 ret = 1;
283         else {
284                 warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
285                 ret = 1;
286         }
287         return ret;
288 }
289
290 static int string_list_set_helper_option(struct helper_data *data,
291                                          const char *name,
292                                          struct string_list *list)
293 {
294         struct strbuf buf = STRBUF_INIT;
295         int i, ret = 0;
296
297         for (i = 0; i < list->nr; i++) {
298                 strbuf_addf(&buf, "option %s ", name);
299                 quote_c_style(list->items[i].string, &buf, NULL, 0);
300                 strbuf_addch(&buf, '\n');
301
302                 if ((ret = strbuf_set_helper_option(data, &buf)))
303                         break;
304                 strbuf_reset(&buf);
305         }
306         strbuf_release(&buf);
307         return ret;
308 }
309
310 static int set_helper_option(struct transport *transport,
311                           const char *name, const char *value)
312 {
313         struct helper_data *data = transport->data;
314         struct strbuf buf = STRBUF_INIT;
315         int i, ret, is_bool = 0;
316
317         get_helper(transport);
318
319         if (!data->option)
320                 return 1;
321
322         if (!strcmp(name, "deepen-not"))
323                 return string_list_set_helper_option(data, name,
324                                                      (struct string_list *)value);
325
326         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
327                 if (!strcmp(name, unsupported_options[i]))
328                         return 1;
329         }
330
331         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
332                 if (!strcmp(name, boolean_options[i])) {
333                         is_bool = 1;
334                         break;
335                 }
336         }
337
338         strbuf_addf(&buf, "option %s ", name);
339         if (is_bool)
340                 strbuf_addstr(&buf, value ? "true" : "false");
341         else
342                 quote_c_style(value, &buf, NULL, 0);
343         strbuf_addch(&buf, '\n');
344
345         ret = strbuf_set_helper_option(data, &buf);
346         strbuf_release(&buf);
347         return ret;
348 }
349
350 static void standard_options(struct transport *t)
351 {
352         char buf[16];
353         int v = t->verbose;
354
355         set_helper_option(t, "progress", t->progress ? "true" : "false");
356
357         xsnprintf(buf, sizeof(buf), "%d", v + 1);
358         set_helper_option(t, "verbosity", buf);
359
360         switch (t->family) {
361         case TRANSPORT_FAMILY_ALL:
362                 /*
363                  * this is already the default,
364                  * do not break old remote helpers by setting "all" here
365                  */
366                 break;
367         case TRANSPORT_FAMILY_IPV4:
368                 set_helper_option(t, "family", "ipv4");
369                 break;
370         case TRANSPORT_FAMILY_IPV6:
371                 set_helper_option(t, "family", "ipv6");
372                 break;
373         }
374 }
375
376 static int release_helper(struct transport *transport)
377 {
378         int res = 0;
379         struct helper_data *data = transport->data;
380         refspec_clear(&data->rs);
381         res = disconnect_helper(transport);
382         free(transport->data);
383         return res;
384 }
385
386 static int fetch_with_fetch(struct transport *transport,
387                             int nr_heads, struct ref **to_fetch)
388 {
389         struct helper_data *data = transport->data;
390         int i;
391         struct strbuf buf = STRBUF_INIT;
392
393         for (i = 0; i < nr_heads; i++) {
394                 const struct ref *posn = to_fetch[i];
395                 if (posn->status & REF_STATUS_UPTODATE)
396                         continue;
397
398                 strbuf_addf(&buf, "fetch %s %s\n",
399                             oid_to_hex(&posn->old_oid),
400                             posn->symref ? posn->symref : posn->name);
401         }
402
403         strbuf_addch(&buf, '\n');
404         sendline(data, &buf);
405
406         while (1) {
407                 const char *name;
408
409                 if (recvline(data, &buf))
410                         exit(128);
411
412                 if (skip_prefix(buf.buf, "lock ", &name)) {
413                         if (transport->pack_lockfile)
414                                 warning(_("%s also locked %s"), data->name, name);
415                         else
416                                 transport->pack_lockfile = xstrdup(name);
417                 }
418                 else if (data->check_connectivity &&
419                          data->transport_options.check_self_contained_and_connected &&
420                          !strcmp(buf.buf, "connectivity-ok"))
421                         data->transport_options.self_contained_and_connected = 1;
422                 else if (!buf.len)
423                         break;
424                 else
425                         warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
426         }
427         strbuf_release(&buf);
428         return 0;
429 }
430
431 static int get_importer(struct transport *transport, struct child_process *fastimport)
432 {
433         struct child_process *helper = get_helper(transport);
434         struct helper_data *data = transport->data;
435         int cat_blob_fd, code;
436         child_process_init(fastimport);
437         fastimport->in = xdup(helper->out);
438         argv_array_push(&fastimport->args, "fast-import");
439         argv_array_push(&fastimport->args, "--allow-unsafe-features");
440         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
441
442         if (data->bidi_import) {
443                 cat_blob_fd = xdup(helper->in);
444                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
445         }
446         fastimport->git_cmd = 1;
447
448         code = start_command(fastimport);
449         return code;
450 }
451
452 static int get_exporter(struct transport *transport,
453                         struct child_process *fastexport,
454                         struct string_list *revlist_args)
455 {
456         struct helper_data *data = transport->data;
457         struct child_process *helper = get_helper(transport);
458         int i;
459
460         child_process_init(fastexport);
461
462         /* we need to duplicate helper->in because we want to use it after
463          * fastexport is done with it. */
464         fastexport->out = dup(helper->in);
465         argv_array_push(&fastexport->args, "fast-export");
466         argv_array_push(&fastexport->args, "--use-done-feature");
467         argv_array_push(&fastexport->args, data->signed_tags ?
468                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
469         if (data->export_marks)
470                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
471         if (data->import_marks)
472                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
473
474         for (i = 0; i < revlist_args->nr; i++)
475                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
476
477         fastexport->git_cmd = 1;
478         return start_command(fastexport);
479 }
480
481 static int fetch_with_import(struct transport *transport,
482                              int nr_heads, struct ref **to_fetch)
483 {
484         struct child_process fastimport;
485         struct helper_data *data = transport->data;
486         int i;
487         struct ref *posn;
488         struct strbuf buf = STRBUF_INIT;
489
490         get_helper(transport);
491
492         if (get_importer(transport, &fastimport))
493                 die(_("couldn't run fast-import"));
494
495         for (i = 0; i < nr_heads; i++) {
496                 posn = to_fetch[i];
497                 if (posn->status & REF_STATUS_UPTODATE)
498                         continue;
499
500                 strbuf_addf(&buf, "import %s\n",
501                             posn->symref ? posn->symref : posn->name);
502                 sendline(data, &buf);
503                 strbuf_reset(&buf);
504         }
505
506         write_constant(data->helper->in, "\n");
507         /*
508          * remote-helpers that advertise the bidi-import capability are required to
509          * buffer the complete batch of import commands until this newline before
510          * sending data to fast-import.
511          * These helpers read back data from fast-import on their stdin, which could
512          * be mixed with import commands, otherwise.
513          */
514
515         if (finish_command(&fastimport))
516                 die(_("error while running fast-import"));
517
518         /*
519          * The fast-import stream of a remote helper that advertises
520          * the "refspec" capability writes to the refs named after the
521          * right hand side of the first refspec matching each ref we
522          * were fetching.
523          *
524          * (If no "refspec" capability was specified, for historical
525          * reasons we default to the equivalent of *:*.)
526          *
527          * Store the result in to_fetch[i].old_sha1.  Callers such
528          * as "git fetch" can use the value to write feedback to the
529          * terminal, populate FETCH_HEAD, and determine what new value
530          * should be written to peer_ref if the update is a
531          * fast-forward or this is a forced update.
532          */
533         for (i = 0; i < nr_heads; i++) {
534                 char *private, *name;
535                 posn = to_fetch[i];
536                 if (posn->status & REF_STATUS_UPTODATE)
537                         continue;
538                 name = posn->symref ? posn->symref : posn->name;
539                 if (data->rs.nr)
540                         private = apply_refspecs(&data->rs, name);
541                 else
542                         private = xstrdup(name);
543                 if (private) {
544                         if (read_ref(private, &posn->old_oid) < 0)
545                                 die(_("could not read ref %s"), private);
546                         free(private);
547                 }
548         }
549         strbuf_release(&buf);
550         return 0;
551 }
552
553 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
554 {
555         struct helper_data *data = transport->data;
556         int ret = 0;
557         int duped;
558         FILE *input;
559         struct child_process *helper;
560
561         helper = get_helper(transport);
562
563         /*
564          * Yes, dup the pipe another time, as we need unbuffered version
565          * of input pipe as FILE*. fclose() closes the underlying fd and
566          * stream buffering only can be changed before first I/O operation
567          * on it.
568          */
569         duped = dup(helper->out);
570         if (duped < 0)
571                 die_errno(_("can't dup helper output fd"));
572         input = xfdopen(duped, "r");
573         setvbuf(input, NULL, _IONBF, 0);
574
575         sendline(data, cmdbuf);
576         if (recvline_fh(input, cmdbuf))
577                 exit(128);
578
579         if (!strcmp(cmdbuf->buf, "")) {
580                 data->no_disconnect_req = 1;
581                 if (debug)
582                         fprintf(stderr, "Debug: Smart transport connection "
583                                 "ready.\n");
584                 ret = 1;
585         } else if (!strcmp(cmdbuf->buf, "fallback")) {
586                 if (debug)
587                         fprintf(stderr, "Debug: Falling back to dumb "
588                                 "transport.\n");
589         } else {
590                 die(_("unknown response to connect: %s"),
591                     cmdbuf->buf);
592         }
593
594         fclose(input);
595         return ret;
596 }
597
598 static int process_connect_service(struct transport *transport,
599                                    const char *name, const char *exec)
600 {
601         struct helper_data *data = transport->data;
602         struct strbuf cmdbuf = STRBUF_INIT;
603         int ret = 0;
604
605         /*
606          * Handle --upload-pack and friends. This is fire and forget...
607          * just warn if it fails.
608          */
609         if (strcmp(name, exec)) {
610                 int r = set_helper_option(transport, "servpath", exec);
611                 if (r > 0)
612                         warning(_("setting remote service path not supported by protocol"));
613                 else if (r < 0)
614                         warning(_("invalid remote service path"));
615         }
616
617         if (data->connect) {
618                 strbuf_addf(&cmdbuf, "connect %s\n", name);
619                 ret = run_connect(transport, &cmdbuf);
620         } else if (data->stateless_connect &&
621                    (get_protocol_version_config() == protocol_v2) &&
622                    !strcmp("git-upload-pack", name)) {
623                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
624                 ret = run_connect(transport, &cmdbuf);
625                 if (ret)
626                         transport->stateless_rpc = 1;
627         }
628
629         strbuf_release(&cmdbuf);
630         return ret;
631 }
632
633 static int process_connect(struct transport *transport,
634                                      int for_push)
635 {
636         struct helper_data *data = transport->data;
637         const char *name;
638         const char *exec;
639
640         name = for_push ? "git-receive-pack" : "git-upload-pack";
641         if (for_push)
642                 exec = data->transport_options.receivepack;
643         else
644                 exec = data->transport_options.uploadpack;
645
646         return process_connect_service(transport, name, exec);
647 }
648
649 static int connect_helper(struct transport *transport, const char *name,
650                    const char *exec, int fd[2])
651 {
652         struct helper_data *data = transport->data;
653
654         /* Get_helper so connect is inited. */
655         get_helper(transport);
656         if (!data->connect)
657                 die(_("operation not supported by protocol"));
658
659         if (!process_connect_service(transport, name, exec))
660                 die(_("can't connect to subservice %s"), name);
661
662         fd[0] = data->helper->out;
663         fd[1] = data->helper->in;
664         return 0;
665 }
666
667 static struct ref *get_refs_list_using_list(struct transport *transport,
668                                             int for_push);
669
670 static int fetch(struct transport *transport,
671                  int nr_heads, struct ref **to_fetch)
672 {
673         struct helper_data *data = transport->data;
674         int i, count;
675
676         get_helper(transport);
677
678         if (process_connect(transport, 0)) {
679                 do_take_over(transport);
680                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
681         }
682
683         if (!data->get_refs_list_called)
684                 get_refs_list_using_list(transport, 0);
685
686         count = 0;
687         for (i = 0; i < nr_heads; i++)
688                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
689                         count++;
690
691         if (!count)
692                 return 0;
693
694         if (data->check_connectivity &&
695             data->transport_options.check_self_contained_and_connected)
696                 set_helper_option(transport, "check-connectivity", "true");
697
698         if (transport->cloning)
699                 set_helper_option(transport, "cloning", "true");
700
701         if (data->transport_options.update_shallow)
702                 set_helper_option(transport, "update-shallow", "true");
703
704         if (data->transport_options.filter_options.choice) {
705                 const char *spec = expand_list_objects_filter_spec(
706                         &data->transport_options.filter_options);
707                 set_helper_option(transport, "filter", spec);
708         }
709
710         if (data->transport_options.negotiation_tips)
711                 warning("Ignoring --negotiation-tip because the protocol does not support it.");
712
713         if (data->fetch)
714                 return fetch_with_fetch(transport, nr_heads, to_fetch);
715
716         if (data->import)
717                 return fetch_with_import(transport, nr_heads, to_fetch);
718
719         return -1;
720 }
721
722 static int push_update_ref_status(struct strbuf *buf,
723                                    struct ref **ref,
724                                    struct ref *remote_refs)
725 {
726         char *refname, *msg;
727         int status, forced = 0;
728
729         if (starts_with(buf->buf, "ok ")) {
730                 status = REF_STATUS_OK;
731                 refname = buf->buf + 3;
732         } else if (starts_with(buf->buf, "error ")) {
733                 status = REF_STATUS_REMOTE_REJECT;
734                 refname = buf->buf + 6;
735         } else
736                 die(_("expected ok/error, helper said '%s'"), buf->buf);
737
738         msg = strchr(refname, ' ');
739         if (msg) {
740                 struct strbuf msg_buf = STRBUF_INIT;
741                 const char *end;
742
743                 *msg++ = '\0';
744                 if (!unquote_c_style(&msg_buf, msg, &end))
745                         msg = strbuf_detach(&msg_buf, NULL);
746                 else
747                         msg = xstrdup(msg);
748                 strbuf_release(&msg_buf);
749
750                 if (!strcmp(msg, "no match")) {
751                         status = REF_STATUS_NONE;
752                         FREE_AND_NULL(msg);
753                 }
754                 else if (!strcmp(msg, "up to date")) {
755                         status = REF_STATUS_UPTODATE;
756                         FREE_AND_NULL(msg);
757                 }
758                 else if (!strcmp(msg, "non-fast forward")) {
759                         status = REF_STATUS_REJECT_NONFASTFORWARD;
760                         FREE_AND_NULL(msg);
761                 }
762                 else if (!strcmp(msg, "already exists")) {
763                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
764                         FREE_AND_NULL(msg);
765                 }
766                 else if (!strcmp(msg, "fetch first")) {
767                         status = REF_STATUS_REJECT_FETCH_FIRST;
768                         FREE_AND_NULL(msg);
769                 }
770                 else if (!strcmp(msg, "needs force")) {
771                         status = REF_STATUS_REJECT_NEEDS_FORCE;
772                         FREE_AND_NULL(msg);
773                 }
774                 else if (!strcmp(msg, "stale info")) {
775                         status = REF_STATUS_REJECT_STALE;
776                         FREE_AND_NULL(msg);
777                 }
778                 else if (!strcmp(msg, "forced update")) {
779                         forced = 1;
780                         FREE_AND_NULL(msg);
781                 }
782         }
783
784         if (*ref)
785                 *ref = find_ref_by_name(*ref, refname);
786         if (!*ref)
787                 *ref = find_ref_by_name(remote_refs, refname);
788         if (!*ref) {
789                 warning(_("helper reported unexpected status of %s"), refname);
790                 return 1;
791         }
792
793         if ((*ref)->status != REF_STATUS_NONE) {
794                 /*
795                  * Earlier, the ref was marked not to be pushed, so ignore the ref
796                  * status reported by the remote helper if the latter is 'no match'.
797                  */
798                 if (status == REF_STATUS_NONE)
799                         return 1;
800         }
801
802         (*ref)->status = status;
803         (*ref)->forced_update |= forced;
804         (*ref)->remote_status = msg;
805         return !(status == REF_STATUS_OK);
806 }
807
808 static int push_update_refs_status(struct helper_data *data,
809                                     struct ref *remote_refs,
810                                     int flags)
811 {
812         struct strbuf buf = STRBUF_INIT;
813         struct ref *ref = remote_refs;
814         int ret = 0;
815
816         for (;;) {
817                 char *private;
818
819                 if (recvline(data, &buf)) {
820                         ret = 1;
821                         break;
822                 }
823
824                 if (!buf.len)
825                         break;
826
827                 if (push_update_ref_status(&buf, &ref, remote_refs))
828                         continue;
829
830                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
831                         continue;
832
833                 /* propagate back the update to the remote namespace */
834                 private = apply_refspecs(&data->rs, ref->name);
835                 if (!private)
836                         continue;
837                 update_ref("update by helper", private, &ref->new_oid, NULL,
838                            0, 0);
839                 free(private);
840         }
841         strbuf_release(&buf);
842         return ret;
843 }
844
845 static void set_common_push_options(struct transport *transport,
846                                    const char *name, int flags)
847 {
848         if (flags & TRANSPORT_PUSH_DRY_RUN) {
849                 if (set_helper_option(transport, "dry-run", "true") != 0)
850                         die(_("helper %s does not support dry-run"), name);
851         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
852                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
853                         die(_("helper %s does not support --signed"), name);
854         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
855                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
856                         die(_("helper %s does not support --signed=if-asked"), name);
857         }
858
859         if (flags & TRANSPORT_PUSH_ATOMIC)
860                 if (set_helper_option(transport, TRANS_OPT_ATOMIC, "true") != 0)
861                         die(_("helper %s does not support --atomic"), name);
862
863         if (flags & TRANSPORT_PUSH_OPTIONS) {
864                 struct string_list_item *item;
865                 for_each_string_list_item(item, transport->push_options)
866                         if (set_helper_option(transport, "push-option", item->string) != 0)
867                                 die(_("helper %s does not support 'push-option'"), name);
868         }
869 }
870
871 static int push_refs_with_push(struct transport *transport,
872                                struct ref *remote_refs, int flags)
873 {
874         int force_all = flags & TRANSPORT_PUSH_FORCE;
875         int mirror = flags & TRANSPORT_PUSH_MIRROR;
876         int atomic = flags & TRANSPORT_PUSH_ATOMIC;
877         struct helper_data *data = transport->data;
878         struct strbuf buf = STRBUF_INIT;
879         struct ref *ref;
880         struct string_list cas_options = STRING_LIST_INIT_DUP;
881         struct string_list_item *cas_option;
882
883         get_helper(transport);
884         if (!data->push)
885                 return 1;
886
887         for (ref = remote_refs; ref; ref = ref->next) {
888                 if (!ref->peer_ref && !mirror)
889                         continue;
890
891                 /* Check for statuses set by set_ref_status_for_push() */
892                 switch (ref->status) {
893                 case REF_STATUS_REJECT_NONFASTFORWARD:
894                 case REF_STATUS_REJECT_STALE:
895                 case REF_STATUS_REJECT_ALREADY_EXISTS:
896                         if (atomic) {
897                                 string_list_clear(&cas_options, 0);
898                                 return 0;
899                         } else
900                                 continue;
901                 case REF_STATUS_UPTODATE:
902                         continue;
903                 default:
904                         ; /* do nothing */
905                 }
906
907                 if (force_all)
908                         ref->force = 1;
909
910                 strbuf_addstr(&buf, "push ");
911                 if (!ref->deletion) {
912                         if (ref->force)
913                                 strbuf_addch(&buf, '+');
914                         if (ref->peer_ref)
915                                 strbuf_addstr(&buf, ref->peer_ref->name);
916                         else
917                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
918                 }
919                 strbuf_addch(&buf, ':');
920                 strbuf_addstr(&buf, ref->name);
921                 strbuf_addch(&buf, '\n');
922
923                 /*
924                  * The "--force-with-lease" options without explicit
925                  * values to expect have already been expanded into
926                  * the ref->old_oid_expect[] field; we can ignore
927                  * transport->smart_options->cas altogether and instead
928                  * can enumerate them from the refs.
929                  */
930                 if (ref->expect_old_sha1) {
931                         struct strbuf cas = STRBUF_INIT;
932                         strbuf_addf(&cas, "%s:%s",
933                                     ref->name, oid_to_hex(&ref->old_oid_expect));
934                         string_list_append_nodup(&cas_options,
935                                                  strbuf_detach(&cas, NULL));
936                 }
937         }
938         if (buf.len == 0) {
939                 string_list_clear(&cas_options, 0);
940                 return 0;
941         }
942
943         for_each_string_list_item(cas_option, &cas_options)
944                 set_helper_option(transport, "cas", cas_option->string);
945         set_common_push_options(transport, data->name, flags);
946
947         strbuf_addch(&buf, '\n');
948         sendline(data, &buf);
949         strbuf_release(&buf);
950         string_list_clear(&cas_options, 0);
951
952         return push_update_refs_status(data, remote_refs, flags);
953 }
954
955 static int push_refs_with_export(struct transport *transport,
956                 struct ref *remote_refs, int flags)
957 {
958         struct ref *ref;
959         struct child_process *helper, exporter;
960         struct helper_data *data = transport->data;
961         struct string_list revlist_args = STRING_LIST_INIT_DUP;
962         struct strbuf buf = STRBUF_INIT;
963
964         if (!data->rs.nr)
965                 die(_("remote-helper doesn't support push; refspec needed"));
966
967         set_common_push_options(transport, data->name, flags);
968         if (flags & TRANSPORT_PUSH_FORCE) {
969                 if (set_helper_option(transport, "force", "true") != 0)
970                         warning(_("helper %s does not support 'force'"), data->name);
971         }
972
973         helper = get_helper(transport);
974
975         write_constant(helper->in, "export\n");
976
977         for (ref = remote_refs; ref; ref = ref->next) {
978                 char *private;
979                 struct object_id oid;
980
981                 private = apply_refspecs(&data->rs, ref->name);
982                 if (private && !get_oid(private, &oid)) {
983                         strbuf_addf(&buf, "^%s", private);
984                         string_list_append_nodup(&revlist_args,
985                                                  strbuf_detach(&buf, NULL));
986                         oidcpy(&ref->old_oid, &oid);
987                 }
988                 free(private);
989
990                 if (ref->peer_ref) {
991                         if (strcmp(ref->name, ref->peer_ref->name)) {
992                                 if (!ref->deletion) {
993                                         const char *name;
994                                         int flag;
995
996                                         /* Follow symbolic refs (mainly for HEAD). */
997                                         name = resolve_ref_unsafe(ref->peer_ref->name,
998                                                                   RESOLVE_REF_READING,
999                                                                   &oid, &flag);
1000                                         if (!name || !(flag & REF_ISSYMREF))
1001                                                 name = ref->peer_ref->name;
1002
1003                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
1004                                 } else
1005                                         strbuf_addf(&buf, ":%s", ref->name);
1006
1007                                 string_list_append(&revlist_args, "--refspec");
1008                                 string_list_append(&revlist_args, buf.buf);
1009                                 strbuf_release(&buf);
1010                         }
1011                         if (!ref->deletion)
1012                                 string_list_append(&revlist_args, ref->peer_ref->name);
1013                 }
1014         }
1015
1016         if (get_exporter(transport, &exporter, &revlist_args))
1017                 die(_("couldn't run fast-export"));
1018
1019         string_list_clear(&revlist_args, 1);
1020
1021         if (finish_command(&exporter))
1022                 die(_("error while running fast-export"));
1023         if (push_update_refs_status(data, remote_refs, flags))
1024                 return 1;
1025
1026         if (data->export_marks) {
1027                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
1028                 rename(buf.buf, data->export_marks);
1029                 strbuf_release(&buf);
1030         }
1031
1032         return 0;
1033 }
1034
1035 static int push_refs(struct transport *transport,
1036                 struct ref *remote_refs, int flags)
1037 {
1038         struct helper_data *data = transport->data;
1039
1040         if (process_connect(transport, 1)) {
1041                 do_take_over(transport);
1042                 return transport->vtable->push_refs(transport, remote_refs, flags);
1043         }
1044
1045         if (!remote_refs) {
1046                 fprintf(stderr,
1047                         _("No refs in common and none specified; doing nothing.\n"
1048                           "Perhaps you should specify a branch such as 'master'.\n"));
1049                 return 0;
1050         }
1051
1052         if (data->push)
1053                 return push_refs_with_push(transport, remote_refs, flags);
1054
1055         if (data->export)
1056                 return push_refs_with_export(transport, remote_refs, flags);
1057
1058         return -1;
1059 }
1060
1061
1062 static int has_attribute(const char *attrs, const char *attr)
1063 {
1064         int len;
1065         if (!attrs)
1066                 return 0;
1067
1068         len = strlen(attr);
1069         for (;;) {
1070                 const char *space = strchrnul(attrs, ' ');
1071                 if (len == space - attrs && !strncmp(attrs, attr, len))
1072                         return 1;
1073                 if (!*space)
1074                         return 0;
1075                 attrs = space + 1;
1076         }
1077 }
1078
1079 static struct ref *get_refs_list(struct transport *transport, int for_push,
1080                                  const struct argv_array *ref_prefixes)
1081 {
1082         get_helper(transport);
1083
1084         if (process_connect(transport, for_push)) {
1085                 do_take_over(transport);
1086                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1087         }
1088
1089         return get_refs_list_using_list(transport, for_push);
1090 }
1091
1092 static struct ref *get_refs_list_using_list(struct transport *transport,
1093                                             int for_push)
1094 {
1095         struct helper_data *data = transport->data;
1096         struct child_process *helper;
1097         struct ref *ret = NULL;
1098         struct ref **tail = &ret;
1099         struct ref *posn;
1100         struct strbuf buf = STRBUF_INIT;
1101
1102         data->get_refs_list_called = 1;
1103         helper = get_helper(transport);
1104
1105         if (data->push && for_push)
1106                 write_str_in_full(helper->in, "list for-push\n");
1107         else
1108                 write_str_in_full(helper->in, "list\n");
1109
1110         while (1) {
1111                 char *eov, *eon;
1112                 if (recvline(data, &buf))
1113                         exit(128);
1114
1115                 if (!*buf.buf)
1116                         break;
1117
1118                 eov = strchr(buf.buf, ' ');
1119                 if (!eov)
1120                         die(_("malformed response in ref list: %s"), buf.buf);
1121                 eon = strchr(eov + 1, ' ');
1122                 *eov = '\0';
1123                 if (eon)
1124                         *eon = '\0';
1125                 *tail = alloc_ref(eov + 1);
1126                 if (buf.buf[0] == '@')
1127                         (*tail)->symref = xstrdup(buf.buf + 1);
1128                 else if (buf.buf[0] != '?')
1129                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1130                 if (eon) {
1131                         if (has_attribute(eon + 1, "unchanged")) {
1132                                 (*tail)->status |= REF_STATUS_UPTODATE;
1133                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1134                                         die(_("could not read ref %s"),
1135                                             (*tail)->name);
1136                         }
1137                 }
1138                 tail = &((*tail)->next);
1139         }
1140         if (debug)
1141                 fprintf(stderr, "Debug: Read ref listing.\n");
1142         strbuf_release(&buf);
1143
1144         for (posn = ret; posn; posn = posn->next)
1145                 resolve_remote_symref(posn, ret);
1146
1147         return ret;
1148 }
1149
1150 static struct transport_vtable vtable = {
1151         set_helper_option,
1152         get_refs_list,
1153         fetch,
1154         push_refs,
1155         connect_helper,
1156         release_helper
1157 };
1158
1159 int transport_helper_init(struct transport *transport, const char *name)
1160 {
1161         struct helper_data *data = xcalloc(1, sizeof(*data));
1162         data->name = name;
1163
1164         transport_check_allowed(name);
1165
1166         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1167                 debug = 1;
1168
1169         transport->data = data;
1170         transport->vtable = &vtable;
1171         transport->smart_options = &(data->transport_options);
1172         return 0;
1173 }
1174
1175 /*
1176  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1177  * buffer less), so attempt reads and writes with up to that size.
1178  */
1179 #define BUFFERSIZE 65536
1180 /* This should be enough to hold debugging message. */
1181 #define PBUFFERSIZE 8192
1182
1183 /* Print bidirectional transfer loop debug message. */
1184 __attribute__((format (printf, 1, 2)))
1185 static void transfer_debug(const char *fmt, ...)
1186 {
1187         /*
1188          * NEEDSWORK: This function is sometimes used from multiple threads, and
1189          * we end up using debug_enabled racily. That "should not matter" since
1190          * we always write the same value, but it's still wrong. This function
1191          * is listed in .tsan-suppressions for the time being.
1192          */
1193
1194         va_list args;
1195         char msgbuf[PBUFFERSIZE];
1196         static int debug_enabled = -1;
1197
1198         if (debug_enabled < 0)
1199                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1200         if (!debug_enabled)
1201                 return;
1202
1203         va_start(args, fmt);
1204         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1205         va_end(args);
1206         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1207 }
1208
1209 /* Stream state: More data may be coming in this direction. */
1210 #define SSTATE_TRANSFERRING 0
1211 /*
1212  * Stream state: No more data coming in this direction, flushing rest of
1213  * data.
1214  */
1215 #define SSTATE_FLUSHING 1
1216 /* Stream state: Transfer in this direction finished. */
1217 #define SSTATE_FINISHED 2
1218
1219 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1220 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1221 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1222
1223 /* Unidirectional transfer. */
1224 struct unidirectional_transfer {
1225         /* Source */
1226         int src;
1227         /* Destination */
1228         int dest;
1229         /* Is source socket? */
1230         int src_is_sock;
1231         /* Is destination socket? */
1232         int dest_is_sock;
1233         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1234         int state;
1235         /* Buffer. */
1236         char buf[BUFFERSIZE];
1237         /* Buffer used. */
1238         size_t bufuse;
1239         /* Name of source. */
1240         const char *src_name;
1241         /* Name of destination. */
1242         const char *dest_name;
1243 };
1244
1245 /* Closes the target (for writing) if transfer has finished. */
1246 static void udt_close_if_finished(struct unidirectional_transfer *t)
1247 {
1248         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1249                 t->state = SSTATE_FINISHED;
1250                 if (t->dest_is_sock)
1251                         shutdown(t->dest, SHUT_WR);
1252                 else
1253                         close(t->dest);
1254                 transfer_debug("Closed %s.", t->dest_name);
1255         }
1256 }
1257
1258 /*
1259  * Tries to read data from source into buffer. If buffer is full,
1260  * no data is read. Returns 0 on success, -1 on error.
1261  */
1262 static int udt_do_read(struct unidirectional_transfer *t)
1263 {
1264         ssize_t bytes;
1265
1266         if (t->bufuse == BUFFERSIZE)
1267                 return 0;       /* No space for more. */
1268
1269         transfer_debug("%s is readable", t->src_name);
1270         bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1271         if (bytes < 0) {
1272                 error_errno(_("read(%s) failed"), t->src_name);
1273                 return -1;
1274         } else if (bytes == 0) {
1275                 transfer_debug("%s EOF (with %i bytes in buffer)",
1276                         t->src_name, (int)t->bufuse);
1277                 t->state = SSTATE_FLUSHING;
1278         } else if (bytes > 0) {
1279                 t->bufuse += bytes;
1280                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1281                         (int)bytes, t->src_name, (int)t->bufuse);
1282         }
1283         return 0;
1284 }
1285
1286 /* Tries to write data from buffer into destination. If buffer is empty,
1287  * no data is written. Returns 0 on success, -1 on error.
1288  */
1289 static int udt_do_write(struct unidirectional_transfer *t)
1290 {
1291         ssize_t bytes;
1292
1293         if (t->bufuse == 0)
1294                 return 0;       /* Nothing to write. */
1295
1296         transfer_debug("%s is writable", t->dest_name);
1297         bytes = xwrite(t->dest, t->buf, t->bufuse);
1298         if (bytes < 0) {
1299                 error_errno(_("write(%s) failed"), t->dest_name);
1300                 return -1;
1301         } else if (bytes > 0) {
1302                 t->bufuse -= bytes;
1303                 if (t->bufuse)
1304                         memmove(t->buf, t->buf + bytes, t->bufuse);
1305                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1306                         (int)bytes, t->dest_name, (int)t->bufuse);
1307         }
1308         return 0;
1309 }
1310
1311
1312 /* State of bidirectional transfer loop. */
1313 struct bidirectional_transfer_state {
1314         /* Direction from program to git. */
1315         struct unidirectional_transfer ptg;
1316         /* Direction from git to program. */
1317         struct unidirectional_transfer gtp;
1318 };
1319
1320 static void *udt_copy_task_routine(void *udt)
1321 {
1322         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1323         while (t->state != SSTATE_FINISHED) {
1324                 if (STATE_NEEDS_READING(t->state))
1325                         if (udt_do_read(t))
1326                                 return NULL;
1327                 if (STATE_NEEDS_WRITING(t->state))
1328                         if (udt_do_write(t))
1329                                 return NULL;
1330                 if (STATE_NEEDS_CLOSING(t->state))
1331                         udt_close_if_finished(t);
1332         }
1333         return udt;     /* Just some non-NULL value. */
1334 }
1335
1336 #ifndef NO_PTHREADS
1337
1338 /*
1339  * Join thread, with appropriate errors on failure. Name is name for the
1340  * thread (for error messages). Returns 0 on success, 1 on failure.
1341  */
1342 static int tloop_join(pthread_t thread, const char *name)
1343 {
1344         int err;
1345         void *tret;
1346         err = pthread_join(thread, &tret);
1347         if (!tret) {
1348                 error(_("%s thread failed"), name);
1349                 return 1;
1350         }
1351         if (err) {
1352                 error(_("%s thread failed to join: %s"), name, strerror(err));
1353                 return 1;
1354         }
1355         return 0;
1356 }
1357
1358 /*
1359  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1360  * -1 on failure.
1361  */
1362 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1363 {
1364         pthread_t gtp_thread;
1365         pthread_t ptg_thread;
1366         int err;
1367         int ret = 0;
1368         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1369                 &s->gtp);
1370         if (err)
1371                 die(_("can't start thread for copying data: %s"), strerror(err));
1372         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1373                 &s->ptg);
1374         if (err)
1375                 die(_("can't start thread for copying data: %s"), strerror(err));
1376
1377         ret |= tloop_join(gtp_thread, "Git to program copy");
1378         ret |= tloop_join(ptg_thread, "Program to git copy");
1379         return ret;
1380 }
1381 #else
1382
1383 /* Close the source and target (for writing) for transfer. */
1384 static void udt_kill_transfer(struct unidirectional_transfer *t)
1385 {
1386         t->state = SSTATE_FINISHED;
1387         /*
1388          * Socket read end left open isn't a disaster if nobody
1389          * attempts to read from it (mingw compat headers do not
1390          * have SHUT_RD)...
1391          *
1392          * We can't fully close the socket since otherwise gtp
1393          * task would first close the socket it sends data to
1394          * while closing the ptg file descriptors.
1395          */
1396         if (!t->src_is_sock)
1397                 close(t->src);
1398         if (t->dest_is_sock)
1399                 shutdown(t->dest, SHUT_WR);
1400         else
1401                 close(t->dest);
1402 }
1403
1404 /*
1405  * Join process, with appropriate errors on failure. Name is name for the
1406  * process (for error messages). Returns 0 on success, 1 on failure.
1407  */
1408 static int tloop_join(pid_t pid, const char *name)
1409 {
1410         int tret;
1411         if (waitpid(pid, &tret, 0) < 0) {
1412                 error_errno(_("%s process failed to wait"), name);
1413                 return 1;
1414         }
1415         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1416                 error(_("%s process failed"), name);
1417                 return 1;
1418         }
1419         return 0;
1420 }
1421
1422 /*
1423  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1424  * -1 on failure.
1425  */
1426 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1427 {
1428         pid_t pid1, pid2;
1429         int ret = 0;
1430
1431         /* Fork thread #1: git to program. */
1432         pid1 = fork();
1433         if (pid1 < 0)
1434                 die_errno(_("can't start thread for copying data"));
1435         else if (pid1 == 0) {
1436                 udt_kill_transfer(&s->ptg);
1437                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1438         }
1439
1440         /* Fork thread #2: program to git. */
1441         pid2 = fork();
1442         if (pid2 < 0)
1443                 die_errno(_("can't start thread for copying data"));
1444         else if (pid2 == 0) {
1445                 udt_kill_transfer(&s->gtp);
1446                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1447         }
1448
1449         /*
1450          * Close both streams in parent as to not interfere with
1451          * end of file detection and wait for both tasks to finish.
1452          */
1453         udt_kill_transfer(&s->gtp);
1454         udt_kill_transfer(&s->ptg);
1455         ret |= tloop_join(pid1, "Git to program copy");
1456         ret |= tloop_join(pid2, "Program to git copy");
1457         return ret;
1458 }
1459 #endif
1460
1461 /*
1462  * Copies data from stdin to output and from input to stdout simultaneously.
1463  * Additionally filtering through given filter. If filter is NULL, uses
1464  * identity filter.
1465  */
1466 int bidirectional_transfer_loop(int input, int output)
1467 {
1468         struct bidirectional_transfer_state state;
1469
1470         /* Fill the state fields. */
1471         state.ptg.src = input;
1472         state.ptg.dest = 1;
1473         state.ptg.src_is_sock = (input == output);
1474         state.ptg.dest_is_sock = 0;
1475         state.ptg.state = SSTATE_TRANSFERRING;
1476         state.ptg.bufuse = 0;
1477         state.ptg.src_name = "remote input";
1478         state.ptg.dest_name = "stdout";
1479
1480         state.gtp.src = 0;
1481         state.gtp.dest = output;
1482         state.gtp.src_is_sock = 0;
1483         state.gtp.dest_is_sock = (input == output);
1484         state.gtp.state = SSTATE_TRANSFERRING;
1485         state.gtp.bufuse = 0;
1486         state.gtp.src_name = "stdin";
1487         state.gtp.dest_name = "remote output";
1488
1489         return tloop_spawnwait_tasks(&state);
1490 }