Merge branch 'jl/maint-1.7.10-recurse-submodules-with-symlink' into maint
[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         for (i = 0; i < nr_heads; i++) {
448                 char *private;
449                 posn = to_fetch[i];
450                 if (posn->status & REF_STATUS_UPTODATE)
451                         continue;
452                 if (data->refspecs)
453                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
454                 else
455                         private = xstrdup(posn->name);
456                 if (private) {
457                         read_ref(private, posn->old_sha1);
458                         free(private);
459                 }
460         }
461         strbuf_release(&buf);
462         return 0;
463 }
464
465 static int process_connect_service(struct transport *transport,
466                                    const char *name, const char *exec)
467 {
468         struct helper_data *data = transport->data;
469         struct strbuf cmdbuf = STRBUF_INIT;
470         struct child_process *helper;
471         int r, duped, ret = 0;
472         FILE *input;
473
474         helper = get_helper(transport);
475
476         /*
477          * Yes, dup the pipe another time, as we need unbuffered version
478          * of input pipe as FILE*. fclose() closes the underlying fd and
479          * stream buffering only can be changed before first I/O operation
480          * on it.
481          */
482         duped = dup(helper->out);
483         if (duped < 0)
484                 die_errno("Can't dup helper output fd");
485         input = xfdopen(duped, "r");
486         setvbuf(input, NULL, _IONBF, 0);
487
488         /*
489          * Handle --upload-pack and friends. This is fire and forget...
490          * just warn if it fails.
491          */
492         if (strcmp(name, exec)) {
493                 r = set_helper_option(transport, "servpath", exec);
494                 if (r > 0)
495                         warning("Setting remote service path not supported by protocol.");
496                 else if (r < 0)
497                         warning("Invalid remote service path.");
498         }
499
500         if (data->connect)
501                 strbuf_addf(&cmdbuf, "connect %s\n", name);
502         else
503                 goto exit;
504
505         sendline(data, &cmdbuf);
506         recvline_fh(input, &cmdbuf);
507         if (!strcmp(cmdbuf.buf, "")) {
508                 data->no_disconnect_req = 1;
509                 if (debug)
510                         fprintf(stderr, "Debug: Smart transport connection "
511                                 "ready.\n");
512                 ret = 1;
513         } else if (!strcmp(cmdbuf.buf, "fallback")) {
514                 if (debug)
515                         fprintf(stderr, "Debug: Falling back to dumb "
516                                 "transport.\n");
517         } else
518                 die("Unknown response to connect: %s",
519                         cmdbuf.buf);
520
521 exit:
522         fclose(input);
523         return ret;
524 }
525
526 static int process_connect(struct transport *transport,
527                                      int for_push)
528 {
529         struct helper_data *data = transport->data;
530         const char *name;
531         const char *exec;
532
533         name = for_push ? "git-receive-pack" : "git-upload-pack";
534         if (for_push)
535                 exec = data->transport_options.receivepack;
536         else
537                 exec = data->transport_options.uploadpack;
538
539         return process_connect_service(transport, name, exec);
540 }
541
542 static int connect_helper(struct transport *transport, const char *name,
543                    const char *exec, int fd[2])
544 {
545         struct helper_data *data = transport->data;
546
547         /* Get_helper so connect is inited. */
548         get_helper(transport);
549         if (!data->connect)
550                 die("Operation not supported by protocol.");
551
552         if (!process_connect_service(transport, name, exec))
553                 die("Can't connect to subservice %s.", name);
554
555         fd[0] = data->helper->out;
556         fd[1] = data->helper->in;
557         return 0;
558 }
559
560 static int fetch(struct transport *transport,
561                  int nr_heads, struct ref **to_fetch)
562 {
563         struct helper_data *data = transport->data;
564         int i, count;
565
566         if (process_connect(transport, 0)) {
567                 do_take_over(transport);
568                 return transport->fetch(transport, nr_heads, to_fetch);
569         }
570
571         count = 0;
572         for (i = 0; i < nr_heads; i++)
573                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
574                         count++;
575
576         if (!count)
577                 return 0;
578
579         if (data->fetch)
580                 return fetch_with_fetch(transport, nr_heads, to_fetch);
581
582         if (data->import)
583                 return fetch_with_import(transport, nr_heads, to_fetch);
584
585         return -1;
586 }
587
588 static void push_update_ref_status(struct strbuf *buf,
589                                    struct ref **ref,
590                                    struct ref *remote_refs)
591 {
592         char *refname, *msg;
593         int status;
594
595         if (!prefixcmp(buf->buf, "ok ")) {
596                 status = REF_STATUS_OK;
597                 refname = buf->buf + 3;
598         } else if (!prefixcmp(buf->buf, "error ")) {
599                 status = REF_STATUS_REMOTE_REJECT;
600                 refname = buf->buf + 6;
601         } else
602                 die("expected ok/error, helper said '%s'", buf->buf);
603
604         msg = strchr(refname, ' ');
605         if (msg) {
606                 struct strbuf msg_buf = STRBUF_INIT;
607                 const char *end;
608
609                 *msg++ = '\0';
610                 if (!unquote_c_style(&msg_buf, msg, &end))
611                         msg = strbuf_detach(&msg_buf, NULL);
612                 else
613                         msg = xstrdup(msg);
614                 strbuf_release(&msg_buf);
615
616                 if (!strcmp(msg, "no match")) {
617                         status = REF_STATUS_NONE;
618                         free(msg);
619                         msg = NULL;
620                 }
621                 else if (!strcmp(msg, "up to date")) {
622                         status = REF_STATUS_UPTODATE;
623                         free(msg);
624                         msg = NULL;
625                 }
626                 else if (!strcmp(msg, "non-fast forward")) {
627                         status = REF_STATUS_REJECT_NONFASTFORWARD;
628                         free(msg);
629                         msg = NULL;
630                 }
631         }
632
633         if (*ref)
634                 *ref = find_ref_by_name(*ref, refname);
635         if (!*ref)
636                 *ref = find_ref_by_name(remote_refs, refname);
637         if (!*ref) {
638                 warning("helper reported unexpected status of %s", refname);
639                 return;
640         }
641
642         if ((*ref)->status != REF_STATUS_NONE) {
643                 /*
644                  * Earlier, the ref was marked not to be pushed, so ignore the ref
645                  * status reported by the remote helper if the latter is 'no match'.
646                  */
647                 if (status == REF_STATUS_NONE)
648                         return;
649         }
650
651         (*ref)->status = status;
652         (*ref)->remote_status = msg;
653 }
654
655 static void push_update_refs_status(struct helper_data *data,
656                                     struct ref *remote_refs)
657 {
658         struct strbuf buf = STRBUF_INIT;
659         struct ref *ref = remote_refs;
660         for (;;) {
661                 recvline(data, &buf);
662                 if (!buf.len)
663                         break;
664
665                 push_update_ref_status(&buf, &ref, remote_refs);
666         }
667         strbuf_release(&buf);
668 }
669
670 static int push_refs_with_push(struct transport *transport,
671                 struct ref *remote_refs, int flags)
672 {
673         int force_all = flags & TRANSPORT_PUSH_FORCE;
674         int mirror = flags & TRANSPORT_PUSH_MIRROR;
675         struct helper_data *data = transport->data;
676         struct strbuf buf = STRBUF_INIT;
677         struct ref *ref;
678
679         get_helper(transport);
680         if (!data->push)
681                 return 1;
682
683         for (ref = remote_refs; ref; ref = ref->next) {
684                 if (!ref->peer_ref && !mirror)
685                         continue;
686
687                 /* Check for statuses set by set_ref_status_for_push() */
688                 switch (ref->status) {
689                 case REF_STATUS_REJECT_NONFASTFORWARD:
690                 case REF_STATUS_UPTODATE:
691                         continue;
692                 default:
693                         ; /* do nothing */
694                 }
695
696                 if (force_all)
697                         ref->force = 1;
698
699                 strbuf_addstr(&buf, "push ");
700                 if (!ref->deletion) {
701                         if (ref->force)
702                                 strbuf_addch(&buf, '+');
703                         if (ref->peer_ref)
704                                 strbuf_addstr(&buf, ref->peer_ref->name);
705                         else
706                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
707                 }
708                 strbuf_addch(&buf, ':');
709                 strbuf_addstr(&buf, ref->name);
710                 strbuf_addch(&buf, '\n');
711         }
712         if (buf.len == 0)
713                 return 0;
714
715         standard_options(transport);
716
717         if (flags & TRANSPORT_PUSH_DRY_RUN) {
718                 if (set_helper_option(transport, "dry-run", "true") != 0)
719                         die("helper %s does not support dry-run", data->name);
720         }
721
722         strbuf_addch(&buf, '\n');
723         sendline(data, &buf);
724         strbuf_release(&buf);
725
726         push_update_refs_status(data, remote_refs);
727         return 0;
728 }
729
730 static int push_refs_with_export(struct transport *transport,
731                 struct ref *remote_refs, int flags)
732 {
733         struct ref *ref;
734         struct child_process *helper, exporter;
735         struct helper_data *data = transport->data;
736         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
737         struct strbuf buf = STRBUF_INIT;
738
739         helper = get_helper(transport);
740
741         write_constant(helper->in, "export\n");
742
743         strbuf_reset(&buf);
744
745         for (ref = remote_refs; ref; ref = ref->next) {
746                 char *private;
747                 unsigned char sha1[20];
748
749                 if (!data->refspecs)
750                         continue;
751                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
752                 if (private && !get_sha1(private, sha1)) {
753                         strbuf_addf(&buf, "^%s", private);
754                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
755                 }
756                 free(private);
757
758                 if (ref->deletion) {
759                         die("remote-helpers do not support ref deletion");
760                 }
761
762                 if (ref->peer_ref)
763                         string_list_append(&revlist_args, ref->peer_ref->name);
764
765         }
766
767         if (get_exporter(transport, &exporter, &revlist_args))
768                 die("Couldn't run fast-export");
769
770         if (finish_command(&exporter))
771                 die("Error while running fast-export");
772         push_update_refs_status(data, remote_refs);
773         return 0;
774 }
775
776 static int push_refs(struct transport *transport,
777                 struct ref *remote_refs, int flags)
778 {
779         struct helper_data *data = transport->data;
780
781         if (process_connect(transport, 1)) {
782                 do_take_over(transport);
783                 return transport->push_refs(transport, remote_refs, flags);
784         }
785
786         if (!remote_refs) {
787                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
788                         "Perhaps you should specify a branch such as 'master'.\n");
789                 return 0;
790         }
791
792         if (data->push)
793                 return push_refs_with_push(transport, remote_refs, flags);
794
795         if (data->export)
796                 return push_refs_with_export(transport, remote_refs, flags);
797
798         return -1;
799 }
800
801
802 static int has_attribute(const char *attrs, const char *attr) {
803         int len;
804         if (!attrs)
805                 return 0;
806
807         len = strlen(attr);
808         for (;;) {
809                 const char *space = strchrnul(attrs, ' ');
810                 if (len == space - attrs && !strncmp(attrs, attr, len))
811                         return 1;
812                 if (!*space)
813                         return 0;
814                 attrs = space + 1;
815         }
816 }
817
818 static struct ref *get_refs_list(struct transport *transport, int for_push)
819 {
820         struct helper_data *data = transport->data;
821         struct child_process *helper;
822         struct ref *ret = NULL;
823         struct ref **tail = &ret;
824         struct ref *posn;
825         struct strbuf buf = STRBUF_INIT;
826
827         helper = get_helper(transport);
828
829         if (process_connect(transport, for_push)) {
830                 do_take_over(transport);
831                 return transport->get_refs_list(transport, for_push);
832         }
833
834         if (data->push && for_push)
835                 write_str_in_full(helper->in, "list for-push\n");
836         else
837                 write_str_in_full(helper->in, "list\n");
838
839         while (1) {
840                 char *eov, *eon;
841                 recvline(data, &buf);
842
843                 if (!*buf.buf)
844                         break;
845
846                 eov = strchr(buf.buf, ' ');
847                 if (!eov)
848                         die("Malformed response in ref list: %s", buf.buf);
849                 eon = strchr(eov + 1, ' ');
850                 *eov = '\0';
851                 if (eon)
852                         *eon = '\0';
853                 *tail = alloc_ref(eov + 1);
854                 if (buf.buf[0] == '@')
855                         (*tail)->symref = xstrdup(buf.buf + 1);
856                 else if (buf.buf[0] != '?')
857                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
858                 if (eon) {
859                         if (has_attribute(eon + 1, "unchanged")) {
860                                 (*tail)->status |= REF_STATUS_UPTODATE;
861                                 read_ref((*tail)->name, (*tail)->old_sha1);
862                         }
863                 }
864                 tail = &((*tail)->next);
865         }
866         if (debug)
867                 fprintf(stderr, "Debug: Read ref listing.\n");
868         strbuf_release(&buf);
869
870         for (posn = ret; posn; posn = posn->next)
871                 resolve_remote_symref(posn, ret);
872
873         return ret;
874 }
875
876 int transport_helper_init(struct transport *transport, const char *name)
877 {
878         struct helper_data *data = xcalloc(sizeof(*data), 1);
879         data->name = name;
880
881         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
882                 debug = 1;
883
884         transport->data = data;
885         transport->set_option = set_helper_option;
886         transport->get_refs_list = get_refs_list;
887         transport->fetch = fetch;
888         transport->push_refs = push_refs;
889         transport->disconnect = release_helper;
890         transport->connect = connect_helper;
891         transport->smart_options = &(data->transport_options);
892         return 0;
893 }
894
895 /*
896  * Linux pipes can buffer 65536 bytes at once (and most platforms can
897  * buffer less), so attempt reads and writes with up to that size.
898  */
899 #define BUFFERSIZE 65536
900 /* This should be enough to hold debugging message. */
901 #define PBUFFERSIZE 8192
902
903 /* Print bidirectional transfer loop debug message. */
904 static void transfer_debug(const char *fmt, ...)
905 {
906         va_list args;
907         char msgbuf[PBUFFERSIZE];
908         static int debug_enabled = -1;
909
910         if (debug_enabled < 0)
911                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
912         if (!debug_enabled)
913                 return;
914
915         va_start(args, fmt);
916         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
917         va_end(args);
918         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
919 }
920
921 /* Stream state: More data may be coming in this direction. */
922 #define SSTATE_TRANSFERING 0
923 /*
924  * Stream state: No more data coming in this direction, flushing rest of
925  * data.
926  */
927 #define SSTATE_FLUSHING 1
928 /* Stream state: Transfer in this direction finished. */
929 #define SSTATE_FINISHED 2
930
931 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
932 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
933 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
934
935 /* Unidirectional transfer. */
936 struct unidirectional_transfer {
937         /* Source */
938         int src;
939         /* Destination */
940         int dest;
941         /* Is source socket? */
942         int src_is_sock;
943         /* Is destination socket? */
944         int dest_is_sock;
945         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
946         int state;
947         /* Buffer. */
948         char buf[BUFFERSIZE];
949         /* Buffer used. */
950         size_t bufuse;
951         /* Name of source. */
952         const char *src_name;
953         /* Name of destination. */
954         const char *dest_name;
955 };
956
957 /* Closes the target (for writing) if transfer has finished. */
958 static void udt_close_if_finished(struct unidirectional_transfer *t)
959 {
960         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
961                 t->state = SSTATE_FINISHED;
962                 if (t->dest_is_sock)
963                         shutdown(t->dest, SHUT_WR);
964                 else
965                         close(t->dest);
966                 transfer_debug("Closed %s.", t->dest_name);
967         }
968 }
969
970 /*
971  * Tries to read read data from source into buffer. If buffer is full,
972  * no data is read. Returns 0 on success, -1 on error.
973  */
974 static int udt_do_read(struct unidirectional_transfer *t)
975 {
976         ssize_t bytes;
977
978         if (t->bufuse == BUFFERSIZE)
979                 return 0;       /* No space for more. */
980
981         transfer_debug("%s is readable", t->src_name);
982         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
983         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
984                 errno != EINTR) {
985                 error("read(%s) failed: %s", t->src_name, strerror(errno));
986                 return -1;
987         } else if (bytes == 0) {
988                 transfer_debug("%s EOF (with %i bytes in buffer)",
989                         t->src_name, t->bufuse);
990                 t->state = SSTATE_FLUSHING;
991         } else if (bytes > 0) {
992                 t->bufuse += bytes;
993                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
994                         (int)bytes, t->src_name, (int)t->bufuse);
995         }
996         return 0;
997 }
998
999 /* Tries to write data from buffer into destination. If buffer is empty,
1000  * no data is written. Returns 0 on success, -1 on error.
1001  */
1002 static int udt_do_write(struct unidirectional_transfer *t)
1003 {
1004         ssize_t bytes;
1005
1006         if (t->bufuse == 0)
1007                 return 0;       /* Nothing to write. */
1008
1009         transfer_debug("%s is writable", t->dest_name);
1010         bytes = write(t->dest, t->buf, t->bufuse);
1011         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1012                 errno != EINTR) {
1013                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1014                 return -1;
1015         } else if (bytes > 0) {
1016                 t->bufuse -= bytes;
1017                 if (t->bufuse)
1018                         memmove(t->buf, t->buf + bytes, t->bufuse);
1019                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1020                         (int)bytes, t->dest_name, (int)t->bufuse);
1021         }
1022         return 0;
1023 }
1024
1025
1026 /* State of bidirectional transfer loop. */
1027 struct bidirectional_transfer_state {
1028         /* Direction from program to git. */
1029         struct unidirectional_transfer ptg;
1030         /* Direction from git to program. */
1031         struct unidirectional_transfer gtp;
1032 };
1033
1034 static void *udt_copy_task_routine(void *udt)
1035 {
1036         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1037         while (t->state != SSTATE_FINISHED) {
1038                 if (STATE_NEEDS_READING(t->state))
1039                         if (udt_do_read(t))
1040                                 return NULL;
1041                 if (STATE_NEEDS_WRITING(t->state))
1042                         if (udt_do_write(t))
1043                                 return NULL;
1044                 if (STATE_NEEDS_CLOSING(t->state))
1045                         udt_close_if_finished(t);
1046         }
1047         return udt;     /* Just some non-NULL value. */
1048 }
1049
1050 #ifndef NO_PTHREADS
1051
1052 /*
1053  * Join thread, with apporiate errors on failure. Name is name for the
1054  * thread (for error messages). Returns 0 on success, 1 on failure.
1055  */
1056 static int tloop_join(pthread_t thread, const char *name)
1057 {
1058         int err;
1059         void *tret;
1060         err = pthread_join(thread, &tret);
1061         if (!tret) {
1062                 error("%s thread failed", name);
1063                 return 1;
1064         }
1065         if (err) {
1066                 error("%s thread failed to join: %s", name, strerror(err));
1067                 return 1;
1068         }
1069         return 0;
1070 }
1071
1072 /*
1073  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1074  * -1 on failure.
1075  */
1076 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1077 {
1078         pthread_t gtp_thread;
1079         pthread_t ptg_thread;
1080         int err;
1081         int ret = 0;
1082         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1083                 &s->gtp);
1084         if (err)
1085                 die("Can't start thread for copying data: %s", strerror(err));
1086         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1087                 &s->ptg);
1088         if (err)
1089                 die("Can't start thread for copying data: %s", strerror(err));
1090
1091         ret |= tloop_join(gtp_thread, "Git to program copy");
1092         ret |= tloop_join(ptg_thread, "Program to git copy");
1093         return ret;
1094 }
1095 #else
1096
1097 /* Close the source and target (for writing) for transfer. */
1098 static void udt_kill_transfer(struct unidirectional_transfer *t)
1099 {
1100         t->state = SSTATE_FINISHED;
1101         /*
1102          * Socket read end left open isn't a disaster if nobody
1103          * attempts to read from it (mingw compat headers do not
1104          * have SHUT_RD)...
1105          *
1106          * We can't fully close the socket since otherwise gtp
1107          * task would first close the socket it sends data to
1108          * while closing the ptg file descriptors.
1109          */
1110         if (!t->src_is_sock)
1111                 close(t->src);
1112         if (t->dest_is_sock)
1113                 shutdown(t->dest, SHUT_WR);
1114         else
1115                 close(t->dest);
1116 }
1117
1118 /*
1119  * Join process, with apporiate errors on failure. Name is name for the
1120  * process (for error messages). Returns 0 on success, 1 on failure.
1121  */
1122 static int tloop_join(pid_t pid, const char *name)
1123 {
1124         int tret;
1125         if (waitpid(pid, &tret, 0) < 0) {
1126                 error("%s process failed to wait: %s", name, strerror(errno));
1127                 return 1;
1128         }
1129         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1130                 error("%s process failed", name);
1131                 return 1;
1132         }
1133         return 0;
1134 }
1135
1136 /*
1137  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1138  * -1 on failure.
1139  */
1140 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1141 {
1142         pid_t pid1, pid2;
1143         int ret = 0;
1144
1145         /* Fork thread #1: git to program. */
1146         pid1 = fork();
1147         if (pid1 < 0)
1148                 die_errno("Can't start thread for copying data");
1149         else if (pid1 == 0) {
1150                 udt_kill_transfer(&s->ptg);
1151                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1152         }
1153
1154         /* Fork thread #2: program to git. */
1155         pid2 = fork();
1156         if (pid2 < 0)
1157                 die_errno("Can't start thread for copying data");
1158         else if (pid2 == 0) {
1159                 udt_kill_transfer(&s->gtp);
1160                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1161         }
1162
1163         /*
1164          * Close both streams in parent as to not interfere with
1165          * end of file detection and wait for both tasks to finish.
1166          */
1167         udt_kill_transfer(&s->gtp);
1168         udt_kill_transfer(&s->ptg);
1169         ret |= tloop_join(pid1, "Git to program copy");
1170         ret |= tloop_join(pid2, "Program to git copy");
1171         return ret;
1172 }
1173 #endif
1174
1175 /*
1176  * Copies data from stdin to output and from input to stdout simultaneously.
1177  * Additionally filtering through given filter. If filter is NULL, uses
1178  * identity filter.
1179  */
1180 int bidirectional_transfer_loop(int input, int output)
1181 {
1182         struct bidirectional_transfer_state state;
1183
1184         /* Fill the state fields. */
1185         state.ptg.src = input;
1186         state.ptg.dest = 1;
1187         state.ptg.src_is_sock = (input == output);
1188         state.ptg.dest_is_sock = 0;
1189         state.ptg.state = SSTATE_TRANSFERING;
1190         state.ptg.bufuse = 0;
1191         state.ptg.src_name = "remote input";
1192         state.ptg.dest_name = "stdout";
1193
1194         state.gtp.src = 0;
1195         state.gtp.dest = output;
1196         state.gtp.src_is_sock = 0;
1197         state.gtp.dest_is_sock = (input == output);
1198         state.gtp.state = SSTATE_TRANSFERING;
1199         state.gtp.bufuse = 0;
1200         state.gtp.src_name = "stdin";
1201         state.gtp.dest_name = "remote output";
1202
1203         return tloop_spawnwait_tasks(&state);
1204 }