Sync with 1.7.11.5
[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 "quote.h"
9 #include "remote.h"
10 #include "string-list.h"
11 #include "thread-utils.h"
12 #include "sigchain.h"
13
14 static int debug;
15
16 struct helper_data {
17         const char *name;
18         struct child_process *helper;
19         FILE *out;
20         unsigned fetch : 1,
21                 import : 1,
22                 export : 1,
23                 option : 1,
24                 push : 1,
25                 connect : 1,
26                 no_disconnect_req : 1;
27         char *export_marks;
28         char *import_marks;
29         /* These go from remote name (as in "list") to private name */
30         struct refspec *refspecs;
31         int refspec_nr;
32         /* Transport options for fetch-pack/send-pack (should one of
33          * those be invoked).
34          */
35         struct git_transport_options transport_options;
36 };
37
38 static void sendline(struct helper_data *helper, struct strbuf *buffer)
39 {
40         if (debug)
41                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
42         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
43                 != buffer->len)
44                 die_errno("Full write to remote helper failed");
45 }
46
47 static int recvline_fh(FILE *helper, struct strbuf *buffer)
48 {
49         strbuf_reset(buffer);
50         if (debug)
51                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
52         if (strbuf_getline(buffer, helper, '\n') == EOF) {
53                 if (debug)
54                         fprintf(stderr, "Debug: Remote helper quit.\n");
55                 exit(128);
56         }
57
58         if (debug)
59                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
60         return 0;
61 }
62
63 static int recvline(struct helper_data *helper, struct strbuf *buffer)
64 {
65         return recvline_fh(helper->out, buffer);
66 }
67
68 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
69 {
70         sendline(helper, buffer);
71         recvline(helper, buffer);
72 }
73
74 static void write_constant(int fd, const char *str)
75 {
76         if (debug)
77                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
78         if (write_in_full(fd, str, strlen(str)) != strlen(str))
79                 die_errno("Full write to remote helper failed");
80 }
81
82 static const char *remove_ext_force(const char *url)
83 {
84         if (url) {
85                 const char *colon = strchr(url, ':');
86                 if (colon && colon[1] == ':')
87                         return colon + 2;
88         }
89         return url;
90 }
91
92 static void do_take_over(struct transport *transport)
93 {
94         struct helper_data *data;
95         data = (struct helper_data *)transport->data;
96         transport_take_over(transport, data->helper);
97         fclose(data->out);
98         free(data);
99 }
100
101 static struct child_process *get_helper(struct transport *transport)
102 {
103         struct helper_data *data = transport->data;
104         struct strbuf buf = STRBUF_INIT;
105         struct child_process *helper;
106         const char **refspecs = NULL;
107         int refspec_nr = 0;
108         int refspec_alloc = 0;
109         int duped;
110         int code;
111         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
112         const char *helper_env[] = {
113                 git_dir_buf,
114                 NULL
115         };
116
117
118         if (data->helper)
119                 return data->helper;
120
121         helper = xcalloc(1, sizeof(*helper));
122         helper->in = -1;
123         helper->out = -1;
124         helper->err = 0;
125         helper->argv = xcalloc(4, sizeof(*helper->argv));
126         strbuf_addf(&buf, "git-remote-%s", data->name);
127         helper->argv[0] = strbuf_detach(&buf, NULL);
128         helper->argv[1] = transport->remote->name;
129         helper->argv[2] = remove_ext_force(transport->url);
130         helper->git_cmd = 0;
131         helper->silent_exec_failure = 1;
132
133         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
134         helper->env = helper_env;
135
136         code = start_command(helper);
137         if (code < 0 && errno == ENOENT)
138                 die("Unable to find remote helper for '%s'", data->name);
139         else if (code != 0)
140                 exit(code);
141
142         data->helper = helper;
143         data->no_disconnect_req = 0;
144
145         /*
146          * Open the output as FILE* so strbuf_getline() can be used.
147          * Do this with duped fd because fclose() will close the fd,
148          * and stuff like taking over will require the fd to remain.
149          */
150         duped = dup(helper->out);
151         if (duped < 0)
152                 die_errno("Can't dup helper output fd");
153         data->out = xfdopen(duped, "r");
154
155         write_constant(helper->in, "capabilities\n");
156
157         while (1) {
158                 const char *capname;
159                 int mandatory = 0;
160                 recvline(data, &buf);
161
162                 if (!*buf.buf)
163                         break;
164
165                 if (*buf.buf == '*') {
166                         capname = buf.buf + 1;
167                         mandatory = 1;
168                 } else
169                         capname = buf.buf;
170
171                 if (debug)
172                         fprintf(stderr, "Debug: Got cap %s\n", capname);
173                 if (!strcmp(capname, "fetch"))
174                         data->fetch = 1;
175                 else if (!strcmp(capname, "option"))
176                         data->option = 1;
177                 else if (!strcmp(capname, "push"))
178                         data->push = 1;
179                 else if (!strcmp(capname, "import"))
180                         data->import = 1;
181                 else if (!strcmp(capname, "export"))
182                         data->export = 1;
183                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
184                         ALLOC_GROW(refspecs,
185                                    refspec_nr + 1,
186                                    refspec_alloc);
187                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
188                 } else if (!strcmp(capname, "connect")) {
189                         data->connect = 1;
190                 } else if (!prefixcmp(capname, "export-marks ")) {
191                         struct strbuf arg = STRBUF_INIT;
192                         strbuf_addstr(&arg, "--export-marks=");
193                         strbuf_addstr(&arg, capname + strlen("export-marks "));
194                         data->export_marks = strbuf_detach(&arg, NULL);
195                 } else if (!prefixcmp(capname, "import-marks")) {
196                         struct strbuf arg = STRBUF_INIT;
197                         strbuf_addstr(&arg, "--import-marks=");
198                         strbuf_addstr(&arg, capname + strlen("import-marks "));
199                         data->import_marks = strbuf_detach(&arg, NULL);
200                 } else if (mandatory) {
201                         die("Unknown mandatory capability %s. This remote "
202                             "helper probably needs newer version of Git.",
203                             capname);
204                 }
205         }
206         if (refspecs) {
207                 int i;
208                 data->refspec_nr = refspec_nr;
209                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
210                 for (i = 0; i < refspec_nr; i++) {
211                         free((char *)refspecs[i]);
212                 }
213                 free(refspecs);
214         }
215         strbuf_release(&buf);
216         if (debug)
217                 fprintf(stderr, "Debug: Capabilities complete.\n");
218         return data->helper;
219 }
220
221 static int disconnect_helper(struct transport *transport)
222 {
223         struct helper_data *data = transport->data;
224         int res = 0;
225
226         if (data->helper) {
227                 if (debug)
228                         fprintf(stderr, "Debug: Disconnecting.\n");
229                 if (!data->no_disconnect_req) {
230                         /*
231                          * Ignore write errors; there's nothing we can do,
232                          * since we're about to close the pipe anyway. And the
233                          * most likely error is EPIPE due to the helper dying
234                          * to report an error itself.
235                          */
236                         sigchain_push(SIGPIPE, SIG_IGN);
237                         xwrite(data->helper->in, "\n", 1);
238                         sigchain_pop(SIGPIPE);
239                 }
240                 close(data->helper->in);
241                 close(data->helper->out);
242                 fclose(data->out);
243                 res = finish_command(data->helper);
244                 free((char *)data->helper->argv[0]);
245                 free(data->helper->argv);
246                 free(data->helper);
247                 data->helper = NULL;
248         }
249         return res;
250 }
251
252 static const char *unsupported_options[] = {
253         TRANS_OPT_UPLOADPACK,
254         TRANS_OPT_RECEIVEPACK,
255         TRANS_OPT_THIN,
256         TRANS_OPT_KEEP
257         };
258 static const char *boolean_options[] = {
259         TRANS_OPT_THIN,
260         TRANS_OPT_KEEP,
261         TRANS_OPT_FOLLOWTAGS
262         };
263
264 static int set_helper_option(struct transport *transport,
265                           const char *name, const char *value)
266 {
267         struct helper_data *data = transport->data;
268         struct strbuf buf = STRBUF_INIT;
269         int i, ret, is_bool = 0;
270
271         get_helper(transport);
272
273         if (!data->option)
274                 return 1;
275
276         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
277                 if (!strcmp(name, unsupported_options[i]))
278                         return 1;
279         }
280
281         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
282                 if (!strcmp(name, boolean_options[i])) {
283                         is_bool = 1;
284                         break;
285                 }
286         }
287
288         strbuf_addf(&buf, "option %s ", name);
289         if (is_bool)
290                 strbuf_addstr(&buf, value ? "true" : "false");
291         else
292                 quote_c_style(value, &buf, NULL, 0);
293         strbuf_addch(&buf, '\n');
294
295         xchgline(data, &buf);
296
297         if (!strcmp(buf.buf, "ok"))
298                 ret = 0;
299         else if (!prefixcmp(buf.buf, "error")) {
300                 ret = -1;
301         } else if (!strcmp(buf.buf, "unsupported"))
302                 ret = 1;
303         else {
304                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
305                 ret = 1;
306         }
307         strbuf_release(&buf);
308         return ret;
309 }
310
311 static void standard_options(struct transport *t)
312 {
313         char buf[16];
314         int n;
315         int v = t->verbose;
316
317         set_helper_option(t, "progress", t->progress ? "true" : "false");
318
319         n = snprintf(buf, sizeof(buf), "%d", v + 1);
320         if (n >= sizeof(buf))
321                 die("impossibly large verbosity value");
322         set_helper_option(t, "verbosity", buf);
323 }
324
325 static int release_helper(struct transport *transport)
326 {
327         int res = 0;
328         struct helper_data *data = transport->data;
329         free_refspec(data->refspec_nr, data->refspecs);
330         data->refspecs = NULL;
331         res = disconnect_helper(transport);
332         free(transport->data);
333         return res;
334 }
335
336 static int fetch_with_fetch(struct transport *transport,
337                             int nr_heads, struct ref **to_fetch)
338 {
339         struct helper_data *data = transport->data;
340         int i;
341         struct strbuf buf = STRBUF_INIT;
342
343         standard_options(transport);
344
345         for (i = 0; i < nr_heads; i++) {
346                 const struct ref *posn = to_fetch[i];
347                 if (posn->status & REF_STATUS_UPTODATE)
348                         continue;
349
350                 strbuf_addf(&buf, "fetch %s %s\n",
351                             sha1_to_hex(posn->old_sha1), posn->name);
352         }
353
354         strbuf_addch(&buf, '\n');
355         sendline(data, &buf);
356
357         while (1) {
358                 recvline(data, &buf);
359
360                 if (!prefixcmp(buf.buf, "lock ")) {
361                         const char *name = buf.buf + 5;
362                         if (transport->pack_lockfile)
363                                 warning("%s also locked %s", data->name, name);
364                         else
365                                 transport->pack_lockfile = xstrdup(name);
366                 }
367                 else if (!buf.len)
368                         break;
369                 else
370                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
371         }
372         strbuf_release(&buf);
373         return 0;
374 }
375
376 static int get_importer(struct transport *transport, struct child_process *fastimport)
377 {
378         struct child_process *helper = get_helper(transport);
379         memset(fastimport, 0, sizeof(*fastimport));
380         fastimport->in = helper->out;
381         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
382         fastimport->argv[0] = "fast-import";
383         fastimport->argv[1] = "--quiet";
384
385         fastimport->git_cmd = 1;
386         return start_command(fastimport);
387 }
388
389 static int get_exporter(struct transport *transport,
390                         struct child_process *fastexport,
391                         struct string_list *revlist_args)
392 {
393         struct helper_data *data = transport->data;
394         struct child_process *helper = get_helper(transport);
395         int argc = 0, i;
396         memset(fastexport, 0, sizeof(*fastexport));
397
398         /* we need to duplicate helper->in because we want to use it after
399          * fastexport is done with it. */
400         fastexport->out = dup(helper->in);
401         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
402         fastexport->argv[argc++] = "fast-export";
403         fastexport->argv[argc++] = "--use-done-feature";
404         if (data->export_marks)
405                 fastexport->argv[argc++] = data->export_marks;
406         if (data->import_marks)
407                 fastexport->argv[argc++] = data->import_marks;
408
409         for (i = 0; i < revlist_args->nr; i++)
410                 fastexport->argv[argc++] = revlist_args->items[i].string;
411
412         fastexport->git_cmd = 1;
413         return start_command(fastexport);
414 }
415
416 static int fetch_with_import(struct transport *transport,
417                              int nr_heads, struct ref **to_fetch)
418 {
419         struct child_process fastimport;
420         struct helper_data *data = transport->data;
421         int i;
422         struct ref *posn;
423         struct strbuf buf = STRBUF_INIT;
424
425         get_helper(transport);
426
427         if (get_importer(transport, &fastimport))
428                 die("Couldn't run fast-import");
429
430         for (i = 0; i < nr_heads; i++) {
431                 posn = to_fetch[i];
432                 if (posn->status & REF_STATUS_UPTODATE)
433                         continue;
434
435                 strbuf_addf(&buf, "import %s\n", posn->name);
436                 sendline(data, &buf);
437                 strbuf_reset(&buf);
438         }
439
440         write_constant(data->helper->in, "\n");
441
442         if (finish_command(&fastimport))
443                 die("Error while running fast-import");
444         free(fastimport.argv);
445         fastimport.argv = NULL;
446
447         /*
448          * The fast-import stream of a remote helper that advertises
449          * the "refspec" capability writes to the refs named after the
450          * right hand side of the first refspec matching each ref we
451          * were fetching.
452          *
453          * (If no "refspec" capability was specified, for historical
454          * reasons we default to *:*.)
455          *
456          * Store the result in to_fetch[i].old_sha1.  Callers such
457          * as "git fetch" can use the value to write feedback to the
458          * terminal, populate FETCH_HEAD, and determine what new value
459          * should be written to peer_ref if the update is a
460          * fast-forward or this is a forced update.
461          */
462         for (i = 0; i < nr_heads; i++) {
463                 char *private;
464                 posn = to_fetch[i];
465                 if (posn->status & REF_STATUS_UPTODATE)
466                         continue;
467                 if (data->refspecs)
468                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
469                 else
470                         private = xstrdup(posn->name);
471                 if (private) {
472                         read_ref(private, posn->old_sha1);
473                         free(private);
474                 }
475         }
476         strbuf_release(&buf);
477         return 0;
478 }
479
480 static int process_connect_service(struct transport *transport,
481                                    const char *name, const char *exec)
482 {
483         struct helper_data *data = transport->data;
484         struct strbuf cmdbuf = STRBUF_INIT;
485         struct child_process *helper;
486         int r, duped, ret = 0;
487         FILE *input;
488
489         helper = get_helper(transport);
490
491         /*
492          * Yes, dup the pipe another time, as we need unbuffered version
493          * of input pipe as FILE*. fclose() closes the underlying fd and
494          * stream buffering only can be changed before first I/O operation
495          * on it.
496          */
497         duped = dup(helper->out);
498         if (duped < 0)
499                 die_errno("Can't dup helper output fd");
500         input = xfdopen(duped, "r");
501         setvbuf(input, NULL, _IONBF, 0);
502
503         /*
504          * Handle --upload-pack and friends. This is fire and forget...
505          * just warn if it fails.
506          */
507         if (strcmp(name, exec)) {
508                 r = set_helper_option(transport, "servpath", exec);
509                 if (r > 0)
510                         warning("Setting remote service path not supported by protocol.");
511                 else if (r < 0)
512                         warning("Invalid remote service path.");
513         }
514
515         if (data->connect)
516                 strbuf_addf(&cmdbuf, "connect %s\n", name);
517         else
518                 goto exit;
519
520         sendline(data, &cmdbuf);
521         recvline_fh(input, &cmdbuf);
522         if (!strcmp(cmdbuf.buf, "")) {
523                 data->no_disconnect_req = 1;
524                 if (debug)
525                         fprintf(stderr, "Debug: Smart transport connection "
526                                 "ready.\n");
527                 ret = 1;
528         } else if (!strcmp(cmdbuf.buf, "fallback")) {
529                 if (debug)
530                         fprintf(stderr, "Debug: Falling back to dumb "
531                                 "transport.\n");
532         } else
533                 die("Unknown response to connect: %s",
534                         cmdbuf.buf);
535
536 exit:
537         fclose(input);
538         return ret;
539 }
540
541 static int process_connect(struct transport *transport,
542                                      int for_push)
543 {
544         struct helper_data *data = transport->data;
545         const char *name;
546         const char *exec;
547
548         name = for_push ? "git-receive-pack" : "git-upload-pack";
549         if (for_push)
550                 exec = data->transport_options.receivepack;
551         else
552                 exec = data->transport_options.uploadpack;
553
554         return process_connect_service(transport, name, exec);
555 }
556
557 static int connect_helper(struct transport *transport, const char *name,
558                    const char *exec, int fd[2])
559 {
560         struct helper_data *data = transport->data;
561
562         /* Get_helper so connect is inited. */
563         get_helper(transport);
564         if (!data->connect)
565                 die("Operation not supported by protocol.");
566
567         if (!process_connect_service(transport, name, exec))
568                 die("Can't connect to subservice %s.", name);
569
570         fd[0] = data->helper->out;
571         fd[1] = data->helper->in;
572         return 0;
573 }
574
575 static int fetch(struct transport *transport,
576                  int nr_heads, struct ref **to_fetch)
577 {
578         struct helper_data *data = transport->data;
579         int i, count;
580
581         if (process_connect(transport, 0)) {
582                 do_take_over(transport);
583                 return transport->fetch(transport, nr_heads, to_fetch);
584         }
585
586         count = 0;
587         for (i = 0; i < nr_heads; i++)
588                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
589                         count++;
590
591         if (!count)
592                 return 0;
593
594         if (data->fetch)
595                 return fetch_with_fetch(transport, nr_heads, to_fetch);
596
597         if (data->import)
598                 return fetch_with_import(transport, nr_heads, to_fetch);
599
600         return -1;
601 }
602
603 static void push_update_ref_status(struct strbuf *buf,
604                                    struct ref **ref,
605                                    struct ref *remote_refs)
606 {
607         char *refname, *msg;
608         int status;
609
610         if (!prefixcmp(buf->buf, "ok ")) {
611                 status = REF_STATUS_OK;
612                 refname = buf->buf + 3;
613         } else if (!prefixcmp(buf->buf, "error ")) {
614                 status = REF_STATUS_REMOTE_REJECT;
615                 refname = buf->buf + 6;
616         } else
617                 die("expected ok/error, helper said '%s'", buf->buf);
618
619         msg = strchr(refname, ' ');
620         if (msg) {
621                 struct strbuf msg_buf = STRBUF_INIT;
622                 const char *end;
623
624                 *msg++ = '\0';
625                 if (!unquote_c_style(&msg_buf, msg, &end))
626                         msg = strbuf_detach(&msg_buf, NULL);
627                 else
628                         msg = xstrdup(msg);
629                 strbuf_release(&msg_buf);
630
631                 if (!strcmp(msg, "no match")) {
632                         status = REF_STATUS_NONE;
633                         free(msg);
634                         msg = NULL;
635                 }
636                 else if (!strcmp(msg, "up to date")) {
637                         status = REF_STATUS_UPTODATE;
638                         free(msg);
639                         msg = NULL;
640                 }
641                 else if (!strcmp(msg, "non-fast forward")) {
642                         status = REF_STATUS_REJECT_NONFASTFORWARD;
643                         free(msg);
644                         msg = NULL;
645                 }
646         }
647
648         if (*ref)
649                 *ref = find_ref_by_name(*ref, refname);
650         if (!*ref)
651                 *ref = find_ref_by_name(remote_refs, refname);
652         if (!*ref) {
653                 warning("helper reported unexpected status of %s", refname);
654                 return;
655         }
656
657         if ((*ref)->status != REF_STATUS_NONE) {
658                 /*
659                  * Earlier, the ref was marked not to be pushed, so ignore the ref
660                  * status reported by the remote helper if the latter is 'no match'.
661                  */
662                 if (status == REF_STATUS_NONE)
663                         return;
664         }
665
666         (*ref)->status = status;
667         (*ref)->remote_status = msg;
668 }
669
670 static void push_update_refs_status(struct helper_data *data,
671                                     struct ref *remote_refs)
672 {
673         struct strbuf buf = STRBUF_INIT;
674         struct ref *ref = remote_refs;
675         for (;;) {
676                 recvline(data, &buf);
677                 if (!buf.len)
678                         break;
679
680                 push_update_ref_status(&buf, &ref, remote_refs);
681         }
682         strbuf_release(&buf);
683 }
684
685 static int push_refs_with_push(struct transport *transport,
686                 struct ref *remote_refs, int flags)
687 {
688         int force_all = flags & TRANSPORT_PUSH_FORCE;
689         int mirror = flags & TRANSPORT_PUSH_MIRROR;
690         struct helper_data *data = transport->data;
691         struct strbuf buf = STRBUF_INIT;
692         struct ref *ref;
693
694         get_helper(transport);
695         if (!data->push)
696                 return 1;
697
698         for (ref = remote_refs; ref; ref = ref->next) {
699                 if (!ref->peer_ref && !mirror)
700                         continue;
701
702                 /* Check for statuses set by set_ref_status_for_push() */
703                 switch (ref->status) {
704                 case REF_STATUS_REJECT_NONFASTFORWARD:
705                 case REF_STATUS_UPTODATE:
706                         continue;
707                 default:
708                         ; /* do nothing */
709                 }
710
711                 if (force_all)
712                         ref->force = 1;
713
714                 strbuf_addstr(&buf, "push ");
715                 if (!ref->deletion) {
716                         if (ref->force)
717                                 strbuf_addch(&buf, '+');
718                         if (ref->peer_ref)
719                                 strbuf_addstr(&buf, ref->peer_ref->name);
720                         else
721                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
722                 }
723                 strbuf_addch(&buf, ':');
724                 strbuf_addstr(&buf, ref->name);
725                 strbuf_addch(&buf, '\n');
726         }
727         if (buf.len == 0)
728                 return 0;
729
730         standard_options(transport);
731
732         if (flags & TRANSPORT_PUSH_DRY_RUN) {
733                 if (set_helper_option(transport, "dry-run", "true") != 0)
734                         die("helper %s does not support dry-run", data->name);
735         }
736
737         strbuf_addch(&buf, '\n');
738         sendline(data, &buf);
739         strbuf_release(&buf);
740
741         push_update_refs_status(data, remote_refs);
742         return 0;
743 }
744
745 static int push_refs_with_export(struct transport *transport,
746                 struct ref *remote_refs, int flags)
747 {
748         struct ref *ref;
749         struct child_process *helper, exporter;
750         struct helper_data *data = transport->data;
751         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
752         struct strbuf buf = STRBUF_INIT;
753
754         helper = get_helper(transport);
755
756         write_constant(helper->in, "export\n");
757
758         strbuf_reset(&buf);
759
760         for (ref = remote_refs; ref; ref = ref->next) {
761                 char *private;
762                 unsigned char sha1[20];
763
764                 if (!data->refspecs)
765                         continue;
766                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
767                 if (private && !get_sha1(private, sha1)) {
768                         strbuf_addf(&buf, "^%s", private);
769                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
770                 }
771                 free(private);
772
773                 if (ref->deletion) {
774                         die("remote-helpers do not support ref deletion");
775                 }
776
777                 if (ref->peer_ref)
778                         string_list_append(&revlist_args, ref->peer_ref->name);
779
780         }
781
782         if (get_exporter(transport, &exporter, &revlist_args))
783                 die("Couldn't run fast-export");
784
785         if (finish_command(&exporter))
786                 die("Error while running fast-export");
787         push_update_refs_status(data, remote_refs);
788         return 0;
789 }
790
791 static int push_refs(struct transport *transport,
792                 struct ref *remote_refs, int flags)
793 {
794         struct helper_data *data = transport->data;
795
796         if (process_connect(transport, 1)) {
797                 do_take_over(transport);
798                 return transport->push_refs(transport, remote_refs, flags);
799         }
800
801         if (!remote_refs) {
802                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
803                         "Perhaps you should specify a branch such as 'master'.\n");
804                 return 0;
805         }
806
807         if (data->push)
808                 return push_refs_with_push(transport, remote_refs, flags);
809
810         if (data->export)
811                 return push_refs_with_export(transport, remote_refs, flags);
812
813         return -1;
814 }
815
816
817 static int has_attribute(const char *attrs, const char *attr) {
818         int len;
819         if (!attrs)
820                 return 0;
821
822         len = strlen(attr);
823         for (;;) {
824                 const char *space = strchrnul(attrs, ' ');
825                 if (len == space - attrs && !strncmp(attrs, attr, len))
826                         return 1;
827                 if (!*space)
828                         return 0;
829                 attrs = space + 1;
830         }
831 }
832
833 static struct ref *get_refs_list(struct transport *transport, int for_push)
834 {
835         struct helper_data *data = transport->data;
836         struct child_process *helper;
837         struct ref *ret = NULL;
838         struct ref **tail = &ret;
839         struct ref *posn;
840         struct strbuf buf = STRBUF_INIT;
841
842         helper = get_helper(transport);
843
844         if (process_connect(transport, for_push)) {
845                 do_take_over(transport);
846                 return transport->get_refs_list(transport, for_push);
847         }
848
849         if (data->push && for_push)
850                 write_str_in_full(helper->in, "list for-push\n");
851         else
852                 write_str_in_full(helper->in, "list\n");
853
854         while (1) {
855                 char *eov, *eon;
856                 recvline(data, &buf);
857
858                 if (!*buf.buf)
859                         break;
860
861                 eov = strchr(buf.buf, ' ');
862                 if (!eov)
863                         die("Malformed response in ref list: %s", buf.buf);
864                 eon = strchr(eov + 1, ' ');
865                 *eov = '\0';
866                 if (eon)
867                         *eon = '\0';
868                 *tail = alloc_ref(eov + 1);
869                 if (buf.buf[0] == '@')
870                         (*tail)->symref = xstrdup(buf.buf + 1);
871                 else if (buf.buf[0] != '?')
872                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
873                 if (eon) {
874                         if (has_attribute(eon + 1, "unchanged")) {
875                                 (*tail)->status |= REF_STATUS_UPTODATE;
876                                 read_ref((*tail)->name, (*tail)->old_sha1);
877                         }
878                 }
879                 tail = &((*tail)->next);
880         }
881         if (debug)
882                 fprintf(stderr, "Debug: Read ref listing.\n");
883         strbuf_release(&buf);
884
885         for (posn = ret; posn; posn = posn->next)
886                 resolve_remote_symref(posn, ret);
887
888         return ret;
889 }
890
891 int transport_helper_init(struct transport *transport, const char *name)
892 {
893         struct helper_data *data = xcalloc(sizeof(*data), 1);
894         data->name = name;
895
896         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
897                 debug = 1;
898
899         transport->data = data;
900         transport->set_option = set_helper_option;
901         transport->get_refs_list = get_refs_list;
902         transport->fetch = fetch;
903         transport->push_refs = push_refs;
904         transport->disconnect = release_helper;
905         transport->connect = connect_helper;
906         transport->smart_options = &(data->transport_options);
907         return 0;
908 }
909
910 /*
911  * Linux pipes can buffer 65536 bytes at once (and most platforms can
912  * buffer less), so attempt reads and writes with up to that size.
913  */
914 #define BUFFERSIZE 65536
915 /* This should be enough to hold debugging message. */
916 #define PBUFFERSIZE 8192
917
918 /* Print bidirectional transfer loop debug message. */
919 static void transfer_debug(const char *fmt, ...)
920 {
921         va_list args;
922         char msgbuf[PBUFFERSIZE];
923         static int debug_enabled = -1;
924
925         if (debug_enabled < 0)
926                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
927         if (!debug_enabled)
928                 return;
929
930         va_start(args, fmt);
931         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
932         va_end(args);
933         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
934 }
935
936 /* Stream state: More data may be coming in this direction. */
937 #define SSTATE_TRANSFERING 0
938 /*
939  * Stream state: No more data coming in this direction, flushing rest of
940  * data.
941  */
942 #define SSTATE_FLUSHING 1
943 /* Stream state: Transfer in this direction finished. */
944 #define SSTATE_FINISHED 2
945
946 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
947 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
948 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
949
950 /* Unidirectional transfer. */
951 struct unidirectional_transfer {
952         /* Source */
953         int src;
954         /* Destination */
955         int dest;
956         /* Is source socket? */
957         int src_is_sock;
958         /* Is destination socket? */
959         int dest_is_sock;
960         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
961         int state;
962         /* Buffer. */
963         char buf[BUFFERSIZE];
964         /* Buffer used. */
965         size_t bufuse;
966         /* Name of source. */
967         const char *src_name;
968         /* Name of destination. */
969         const char *dest_name;
970 };
971
972 /* Closes the target (for writing) if transfer has finished. */
973 static void udt_close_if_finished(struct unidirectional_transfer *t)
974 {
975         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
976                 t->state = SSTATE_FINISHED;
977                 if (t->dest_is_sock)
978                         shutdown(t->dest, SHUT_WR);
979                 else
980                         close(t->dest);
981                 transfer_debug("Closed %s.", t->dest_name);
982         }
983 }
984
985 /*
986  * Tries to read read data from source into buffer. If buffer is full,
987  * no data is read. Returns 0 on success, -1 on error.
988  */
989 static int udt_do_read(struct unidirectional_transfer *t)
990 {
991         ssize_t bytes;
992
993         if (t->bufuse == BUFFERSIZE)
994                 return 0;       /* No space for more. */
995
996         transfer_debug("%s is readable", t->src_name);
997         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
998         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
999                 errno != EINTR) {
1000                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1001                 return -1;
1002         } else if (bytes == 0) {
1003                 transfer_debug("%s EOF (with %i bytes in buffer)",
1004                         t->src_name, t->bufuse);
1005                 t->state = SSTATE_FLUSHING;
1006         } else if (bytes > 0) {
1007                 t->bufuse += bytes;
1008                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1009                         (int)bytes, t->src_name, (int)t->bufuse);
1010         }
1011         return 0;
1012 }
1013
1014 /* Tries to write data from buffer into destination. If buffer is empty,
1015  * no data is written. Returns 0 on success, -1 on error.
1016  */
1017 static int udt_do_write(struct unidirectional_transfer *t)
1018 {
1019         ssize_t bytes;
1020
1021         if (t->bufuse == 0)
1022                 return 0;       /* Nothing to write. */
1023
1024         transfer_debug("%s is writable", t->dest_name);
1025         bytes = write(t->dest, t->buf, t->bufuse);
1026         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1027                 errno != EINTR) {
1028                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1029                 return -1;
1030         } else if (bytes > 0) {
1031                 t->bufuse -= bytes;
1032                 if (t->bufuse)
1033                         memmove(t->buf, t->buf + bytes, t->bufuse);
1034                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1035                         (int)bytes, t->dest_name, (int)t->bufuse);
1036         }
1037         return 0;
1038 }
1039
1040
1041 /* State of bidirectional transfer loop. */
1042 struct bidirectional_transfer_state {
1043         /* Direction from program to git. */
1044         struct unidirectional_transfer ptg;
1045         /* Direction from git to program. */
1046         struct unidirectional_transfer gtp;
1047 };
1048
1049 static void *udt_copy_task_routine(void *udt)
1050 {
1051         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1052         while (t->state != SSTATE_FINISHED) {
1053                 if (STATE_NEEDS_READING(t->state))
1054                         if (udt_do_read(t))
1055                                 return NULL;
1056                 if (STATE_NEEDS_WRITING(t->state))
1057                         if (udt_do_write(t))
1058                                 return NULL;
1059                 if (STATE_NEEDS_CLOSING(t->state))
1060                         udt_close_if_finished(t);
1061         }
1062         return udt;     /* Just some non-NULL value. */
1063 }
1064
1065 #ifndef NO_PTHREADS
1066
1067 /*
1068  * Join thread, with apporiate errors on failure. Name is name for the
1069  * thread (for error messages). Returns 0 on success, 1 on failure.
1070  */
1071 static int tloop_join(pthread_t thread, const char *name)
1072 {
1073         int err;
1074         void *tret;
1075         err = pthread_join(thread, &tret);
1076         if (!tret) {
1077                 error("%s thread failed", name);
1078                 return 1;
1079         }
1080         if (err) {
1081                 error("%s thread failed to join: %s", name, strerror(err));
1082                 return 1;
1083         }
1084         return 0;
1085 }
1086
1087 /*
1088  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1089  * -1 on failure.
1090  */
1091 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1092 {
1093         pthread_t gtp_thread;
1094         pthread_t ptg_thread;
1095         int err;
1096         int ret = 0;
1097         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1098                 &s->gtp);
1099         if (err)
1100                 die("Can't start thread for copying data: %s", strerror(err));
1101         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1102                 &s->ptg);
1103         if (err)
1104                 die("Can't start thread for copying data: %s", strerror(err));
1105
1106         ret |= tloop_join(gtp_thread, "Git to program copy");
1107         ret |= tloop_join(ptg_thread, "Program to git copy");
1108         return ret;
1109 }
1110 #else
1111
1112 /* Close the source and target (for writing) for transfer. */
1113 static void udt_kill_transfer(struct unidirectional_transfer *t)
1114 {
1115         t->state = SSTATE_FINISHED;
1116         /*
1117          * Socket read end left open isn't a disaster if nobody
1118          * attempts to read from it (mingw compat headers do not
1119          * have SHUT_RD)...
1120          *
1121          * We can't fully close the socket since otherwise gtp
1122          * task would first close the socket it sends data to
1123          * while closing the ptg file descriptors.
1124          */
1125         if (!t->src_is_sock)
1126                 close(t->src);
1127         if (t->dest_is_sock)
1128                 shutdown(t->dest, SHUT_WR);
1129         else
1130                 close(t->dest);
1131 }
1132
1133 /*
1134  * Join process, with apporiate errors on failure. Name is name for the
1135  * process (for error messages). Returns 0 on success, 1 on failure.
1136  */
1137 static int tloop_join(pid_t pid, const char *name)
1138 {
1139         int tret;
1140         if (waitpid(pid, &tret, 0) < 0) {
1141                 error("%s process failed to wait: %s", name, strerror(errno));
1142                 return 1;
1143         }
1144         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1145                 error("%s process failed", name);
1146                 return 1;
1147         }
1148         return 0;
1149 }
1150
1151 /*
1152  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1153  * -1 on failure.
1154  */
1155 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1156 {
1157         pid_t pid1, pid2;
1158         int ret = 0;
1159
1160         /* Fork thread #1: git to program. */
1161         pid1 = fork();
1162         if (pid1 < 0)
1163                 die_errno("Can't start thread for copying data");
1164         else if (pid1 == 0) {
1165                 udt_kill_transfer(&s->ptg);
1166                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1167         }
1168
1169         /* Fork thread #2: program to git. */
1170         pid2 = fork();
1171         if (pid2 < 0)
1172                 die_errno("Can't start thread for copying data");
1173         else if (pid2 == 0) {
1174                 udt_kill_transfer(&s->gtp);
1175                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1176         }
1177
1178         /*
1179          * Close both streams in parent as to not interfere with
1180          * end of file detection and wait for both tasks to finish.
1181          */
1182         udt_kill_transfer(&s->gtp);
1183         udt_kill_transfer(&s->ptg);
1184         ret |= tloop_join(pid1, "Git to program copy");
1185         ret |= tloop_join(pid2, "Program to git copy");
1186         return ret;
1187 }
1188 #endif
1189
1190 /*
1191  * Copies data from stdin to output and from input to stdout simultaneously.
1192  * Additionally filtering through given filter. If filter is NULL, uses
1193  * identity filter.
1194  */
1195 int bidirectional_transfer_loop(int input, int output)
1196 {
1197         struct bidirectional_transfer_state state;
1198
1199         /* Fill the state fields. */
1200         state.ptg.src = input;
1201         state.ptg.dest = 1;
1202         state.ptg.src_is_sock = (input == output);
1203         state.ptg.dest_is_sock = 0;
1204         state.ptg.state = SSTATE_TRANSFERING;
1205         state.ptg.bufuse = 0;
1206         state.ptg.src_name = "remote input";
1207         state.ptg.dest_name = "stdout";
1208
1209         state.gtp.src = 0;
1210         state.gtp.dest = output;
1211         state.gtp.src_is_sock = 0;
1212         state.gtp.dest_is_sock = (input == output);
1213         state.gtp.state = SSTATE_TRANSFERING;
1214         state.gtp.bufuse = 0;
1215         state.gtp.src_name = "stdin";
1216         state.gtp.dest_name = "remote output";
1217
1218         return tloop_spawnwait_tasks(&state);
1219 }