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