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