Merge git://github.com/git-l10n/git-po
[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 #include "argv-array.h"
14 #include "refs.h"
15
16 static int debug;
17
18 struct helper_data {
19         const char *name;
20         struct child_process *helper;
21         FILE *out;
22         unsigned fetch : 1,
23                 import : 1,
24                 bidi_import : 1,
25                 export : 1,
26                 option : 1,
27                 push : 1,
28                 connect : 1,
29                 signed_tags : 1,
30                 check_connectivity : 1,
31                 no_disconnect_req : 1,
32                 no_private_update : 1;
33         char *export_marks;
34         char *import_marks;
35         /* These go from remote name (as in "list") to private name */
36         struct refspec *refspecs;
37         int refspec_nr;
38         /* Transport options for fetch-pack/send-pack (should one of
39          * those be invoked).
40          */
41         struct git_transport_options transport_options;
42 };
43
44 static void sendline(struct helper_data *helper, struct strbuf *buffer)
45 {
46         if (debug)
47                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
48         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
49                 != buffer->len)
50                 die_errno("Full write to remote helper failed");
51 }
52
53 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
54 {
55         strbuf_reset(buffer);
56         if (debug)
57                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
58         if (strbuf_getline(buffer, helper, '\n') == EOF) {
59                 if (debug)
60                         fprintf(stderr, "Debug: Remote helper quit.\n");
61                 exit(128);
62         }
63
64         if (debug)
65                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
66         return 0;
67 }
68
69 static int recvline(struct helper_data *helper, struct strbuf *buffer)
70 {
71         return recvline_fh(helper->out, buffer, helper->name);
72 }
73
74 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
75 {
76         sendline(helper, buffer);
77         recvline(helper, buffer);
78 }
79
80 static void write_constant(int fd, const char *str)
81 {
82         if (debug)
83                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
84         if (write_in_full(fd, str, strlen(str)) != strlen(str))
85                 die_errno("Full write to remote helper failed");
86 }
87
88 static const char *remove_ext_force(const char *url)
89 {
90         if (url) {
91                 const char *colon = strchr(url, ':');
92                 if (colon && colon[1] == ':')
93                         return colon + 2;
94         }
95         return url;
96 }
97
98 static void do_take_over(struct transport *transport)
99 {
100         struct helper_data *data;
101         data = (struct helper_data *)transport->data;
102         transport_take_over(transport, data->helper);
103         fclose(data->out);
104         free(data);
105 }
106
107 static struct child_process *get_helper(struct transport *transport)
108 {
109         struct helper_data *data = transport->data;
110         struct argv_array argv = ARGV_ARRAY_INIT;
111         struct strbuf buf = STRBUF_INIT;
112         struct child_process *helper;
113         const char **refspecs = NULL;
114         int refspec_nr = 0;
115         int refspec_alloc = 0;
116         int duped;
117         int code;
118         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
119         const char *helper_env[] = {
120                 git_dir_buf,
121                 NULL
122         };
123
124
125         if (data->helper)
126                 return data->helper;
127
128         helper = xcalloc(1, sizeof(*helper));
129         helper->in = -1;
130         helper->out = -1;
131         helper->err = 0;
132         argv_array_pushf(&argv, "git-remote-%s", data->name);
133         argv_array_push(&argv, transport->remote->name);
134         argv_array_push(&argv, remove_ext_force(transport->url));
135         helper->argv = argv_array_detach(&argv, NULL);
136         helper->git_cmd = 0;
137         helper->silent_exec_failure = 1;
138
139         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
140         helper->env = helper_env;
141
142         code = start_command(helper);
143         if (code < 0 && errno == ENOENT)
144                 die("Unable to find remote helper for '%s'", data->name);
145         else if (code != 0)
146                 exit(code);
147
148         data->helper = helper;
149         data->no_disconnect_req = 0;
150
151         /*
152          * Open the output as FILE* so strbuf_getline() can be used.
153          * Do this with duped fd because fclose() will close the fd,
154          * and stuff like taking over will require the fd to remain.
155          */
156         duped = dup(helper->out);
157         if (duped < 0)
158                 die_errno("Can't dup helper output fd");
159         data->out = xfdopen(duped, "r");
160
161         write_constant(helper->in, "capabilities\n");
162
163         while (1) {
164                 const char *capname;
165                 int mandatory = 0;
166                 recvline(data, &buf);
167
168                 if (!*buf.buf)
169                         break;
170
171                 if (*buf.buf == '*') {
172                         capname = buf.buf + 1;
173                         mandatory = 1;
174                 } else
175                         capname = buf.buf;
176
177                 if (debug)
178                         fprintf(stderr, "Debug: Got cap %s\n", capname);
179                 if (!strcmp(capname, "fetch"))
180                         data->fetch = 1;
181                 else if (!strcmp(capname, "option"))
182                         data->option = 1;
183                 else if (!strcmp(capname, "push"))
184                         data->push = 1;
185                 else if (!strcmp(capname, "import"))
186                         data->import = 1;
187                 else if (!strcmp(capname, "bidi-import"))
188                         data->bidi_import = 1;
189                 else if (!strcmp(capname, "export"))
190                         data->export = 1;
191                 else if (!strcmp(capname, "check-connectivity"))
192                         data->check_connectivity = 1;
193                 else if (!data->refspecs && starts_with(capname, "refspec ")) {
194                         ALLOC_GROW(refspecs,
195                                    refspec_nr + 1,
196                                    refspec_alloc);
197                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
198                 } else if (!strcmp(capname, "connect")) {
199                         data->connect = 1;
200                 } else if (!strcmp(capname, "signed-tags")) {
201                         data->signed_tags = 1;
202                 } else if (starts_with(capname, "export-marks ")) {
203                         struct strbuf arg = STRBUF_INIT;
204                         strbuf_addstr(&arg, "--export-marks=");
205                         strbuf_addstr(&arg, capname + strlen("export-marks "));
206                         data->export_marks = strbuf_detach(&arg, NULL);
207                 } else if (starts_with(capname, "import-marks")) {
208                         struct strbuf arg = STRBUF_INIT;
209                         strbuf_addstr(&arg, "--import-marks=");
210                         strbuf_addstr(&arg, capname + strlen("import-marks "));
211                         data->import_marks = strbuf_detach(&arg, NULL);
212                 } else if (starts_with(capname, "no-private-update")) {
213                         data->no_private_update = 1;
214                 } else if (mandatory) {
215                         die("Unknown mandatory capability %s. This remote "
216                             "helper probably needs newer version of Git.",
217                             capname);
218                 }
219         }
220         if (refspecs) {
221                 int i;
222                 data->refspec_nr = refspec_nr;
223                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
224                 for (i = 0; i < refspec_nr; i++)
225                         free((char *)refspecs[i]);
226                 free(refspecs);
227         } else if (data->import || data->bidi_import || data->export) {
228                 warning("This remote helper should implement refspec capability.");
229         }
230         strbuf_release(&buf);
231         if (debug)
232                 fprintf(stderr, "Debug: Capabilities complete.\n");
233         return data->helper;
234 }
235
236 static int disconnect_helper(struct transport *transport)
237 {
238         struct helper_data *data = transport->data;
239         int res = 0;
240
241         if (data->helper) {
242                 if (debug)
243                         fprintf(stderr, "Debug: Disconnecting.\n");
244                 if (!data->no_disconnect_req) {
245                         /*
246                          * Ignore write errors; there's nothing we can do,
247                          * since we're about to close the pipe anyway. And the
248                          * most likely error is EPIPE due to the helper dying
249                          * to report an error itself.
250                          */
251                         sigchain_push(SIGPIPE, SIG_IGN);
252                         xwrite(data->helper->in, "\n", 1);
253                         sigchain_pop(SIGPIPE);
254                 }
255                 close(data->helper->in);
256                 close(data->helper->out);
257                 fclose(data->out);
258                 res = finish_command(data->helper);
259                 argv_array_free_detached(data->helper->argv);
260                 free(data->helper);
261                 data->helper = NULL;
262         }
263         return res;
264 }
265
266 static const char *unsupported_options[] = {
267         TRANS_OPT_UPLOADPACK,
268         TRANS_OPT_RECEIVEPACK,
269         TRANS_OPT_THIN,
270         TRANS_OPT_KEEP
271         };
272
273 static const char *boolean_options[] = {
274         TRANS_OPT_THIN,
275         TRANS_OPT_KEEP,
276         TRANS_OPT_FOLLOWTAGS
277         };
278
279 static int set_helper_option(struct transport *transport,
280                           const char *name, const char *value)
281 {
282         struct helper_data *data = transport->data;
283         struct strbuf buf = STRBUF_INIT;
284         int i, ret, is_bool = 0;
285
286         get_helper(transport);
287
288         if (!data->option)
289                 return 1;
290
291         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
292                 if (!strcmp(name, unsupported_options[i]))
293                         return 1;
294         }
295
296         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
297                 if (!strcmp(name, boolean_options[i])) {
298                         is_bool = 1;
299                         break;
300                 }
301         }
302
303         strbuf_addf(&buf, "option %s ", name);
304         if (is_bool)
305                 strbuf_addstr(&buf, value ? "true" : "false");
306         else
307                 quote_c_style(value, &buf, NULL, 0);
308         strbuf_addch(&buf, '\n');
309
310         xchgline(data, &buf);
311
312         if (!strcmp(buf.buf, "ok"))
313                 ret = 0;
314         else if (starts_with(buf.buf, "error")) {
315                 ret = -1;
316         } else if (!strcmp(buf.buf, "unsupported"))
317                 ret = 1;
318         else {
319                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
320                 ret = 1;
321         }
322         strbuf_release(&buf);
323         return ret;
324 }
325
326 static void standard_options(struct transport *t)
327 {
328         char buf[16];
329         int n;
330         int v = t->verbose;
331
332         set_helper_option(t, "progress", t->progress ? "true" : "false");
333
334         n = snprintf(buf, sizeof(buf), "%d", v + 1);
335         if (n >= sizeof(buf))
336                 die("impossibly large verbosity value");
337         set_helper_option(t, "verbosity", buf);
338 }
339
340 static int release_helper(struct transport *transport)
341 {
342         int res = 0;
343         struct helper_data *data = transport->data;
344         free_refspec(data->refspec_nr, data->refspecs);
345         data->refspecs = NULL;
346         res = disconnect_helper(transport);
347         free(transport->data);
348         return res;
349 }
350
351 static int fetch_with_fetch(struct transport *transport,
352                             int nr_heads, struct ref **to_fetch)
353 {
354         struct helper_data *data = transport->data;
355         int i;
356         struct strbuf buf = STRBUF_INIT;
357
358         standard_options(transport);
359         if (data->check_connectivity &&
360             data->transport_options.check_self_contained_and_connected)
361                 set_helper_option(transport, "check-connectivity", "true");
362
363         if (transport->cloning)
364                 set_helper_option(transport, "cloning", "true");
365
366         if (data->transport_options.update_shallow)
367                 set_helper_option(transport, "update-shallow", "true");
368
369         for (i = 0; i < nr_heads; i++) {
370                 const struct ref *posn = to_fetch[i];
371                 if (posn->status & REF_STATUS_UPTODATE)
372                         continue;
373
374                 strbuf_addf(&buf, "fetch %s %s\n",
375                             sha1_to_hex(posn->old_sha1), posn->name);
376         }
377
378         strbuf_addch(&buf, '\n');
379         sendline(data, &buf);
380
381         while (1) {
382                 recvline(data, &buf);
383
384                 if (starts_with(buf.buf, "lock ")) {
385                         const char *name = buf.buf + 5;
386                         if (transport->pack_lockfile)
387                                 warning("%s also locked %s", data->name, name);
388                         else
389                                 transport->pack_lockfile = xstrdup(name);
390                 }
391                 else if (data->check_connectivity &&
392                          data->transport_options.check_self_contained_and_connected &&
393                          !strcmp(buf.buf, "connectivity-ok"))
394                         data->transport_options.self_contained_and_connected = 1;
395                 else if (!buf.len)
396                         break;
397                 else
398                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
399         }
400         strbuf_release(&buf);
401         return 0;
402 }
403
404 static int get_importer(struct transport *transport, struct child_process *fastimport)
405 {
406         struct child_process *helper = get_helper(transport);
407         struct helper_data *data = transport->data;
408         struct argv_array argv = ARGV_ARRAY_INIT;
409         int cat_blob_fd, code;
410         memset(fastimport, 0, sizeof(*fastimport));
411         fastimport->in = helper->out;
412         argv_array_push(&argv, "fast-import");
413         argv_array_push(&argv, debug ? "--stats" : "--quiet");
414
415         if (data->bidi_import) {
416                 cat_blob_fd = xdup(helper->in);
417                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
418         }
419         fastimport->argv = argv.argv;
420         fastimport->git_cmd = 1;
421
422         code = start_command(fastimport);
423         return code;
424 }
425
426 static int get_exporter(struct transport *transport,
427                         struct child_process *fastexport,
428                         struct string_list *revlist_args)
429 {
430         struct helper_data *data = transport->data;
431         struct child_process *helper = get_helper(transport);
432         int argc = 0, i;
433         memset(fastexport, 0, sizeof(*fastexport));
434
435         /* we need to duplicate helper->in because we want to use it after
436          * fastexport is done with it. */
437         fastexport->out = dup(helper->in);
438         fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
439         fastexport->argv[argc++] = "fast-export";
440         fastexport->argv[argc++] = "--use-done-feature";
441         fastexport->argv[argc++] = data->signed_tags ?
442                 "--signed-tags=verbatim" : "--signed-tags=warn-strip";
443         if (data->export_marks)
444                 fastexport->argv[argc++] = data->export_marks;
445         if (data->import_marks)
446                 fastexport->argv[argc++] = data->import_marks;
447
448         for (i = 0; i < revlist_args->nr; i++)
449                 fastexport->argv[argc++] = revlist_args->items[i].string;
450
451         fastexport->git_cmd = 1;
452         return start_command(fastexport);
453 }
454
455 static int fetch_with_import(struct transport *transport,
456                              int nr_heads, struct ref **to_fetch)
457 {
458         struct child_process fastimport;
459         struct helper_data *data = transport->data;
460         int i;
461         struct ref *posn;
462         struct strbuf buf = STRBUF_INIT;
463
464         get_helper(transport);
465
466         if (get_importer(transport, &fastimport))
467                 die("Couldn't run fast-import");
468
469         for (i = 0; i < nr_heads; i++) {
470                 posn = to_fetch[i];
471                 if (posn->status & REF_STATUS_UPTODATE)
472                         continue;
473
474                 strbuf_addf(&buf, "import %s\n", posn->name);
475                 sendline(data, &buf);
476                 strbuf_reset(&buf);
477         }
478
479         write_constant(data->helper->in, "\n");
480         /*
481          * remote-helpers that advertise the bidi-import capability are required to
482          * buffer the complete batch of import commands until this newline before
483          * sending data to fast-import.
484          * These helpers read back data from fast-import on their stdin, which could
485          * be mixed with import commands, otherwise.
486          */
487
488         if (finish_command(&fastimport))
489                 die("Error while running fast-import");
490         argv_array_free_detached(fastimport.argv);
491
492         /*
493          * The fast-import stream of a remote helper that advertises
494          * the "refspec" capability writes to the refs named after the
495          * right hand side of the first refspec matching each ref we
496          * were fetching.
497          *
498          * (If no "refspec" capability was specified, for historical
499          * reasons we default to the equivalent of *:*.)
500          *
501          * Store the result in to_fetch[i].old_sha1.  Callers such
502          * as "git fetch" can use the value to write feedback to the
503          * terminal, populate FETCH_HEAD, and determine what new value
504          * should be written to peer_ref if the update is a
505          * fast-forward or this is a forced update.
506          */
507         for (i = 0; i < nr_heads; i++) {
508                 char *private;
509                 posn = to_fetch[i];
510                 if (posn->status & REF_STATUS_UPTODATE)
511                         continue;
512                 if (data->refspecs)
513                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
514                 else
515                         private = xstrdup(posn->name);
516                 if (private) {
517                         read_ref(private, posn->old_sha1);
518                         free(private);
519                 }
520         }
521         strbuf_release(&buf);
522         return 0;
523 }
524
525 static int process_connect_service(struct transport *transport,
526                                    const char *name, const char *exec)
527 {
528         struct helper_data *data = transport->data;
529         struct strbuf cmdbuf = STRBUF_INIT;
530         struct child_process *helper;
531         int r, duped, ret = 0;
532         FILE *input;
533
534         helper = get_helper(transport);
535
536         /*
537          * Yes, dup the pipe another time, as we need unbuffered version
538          * of input pipe as FILE*. fclose() closes the underlying fd and
539          * stream buffering only can be changed before first I/O operation
540          * on it.
541          */
542         duped = dup(helper->out);
543         if (duped < 0)
544                 die_errno("Can't dup helper output fd");
545         input = xfdopen(duped, "r");
546         setvbuf(input, NULL, _IONBF, 0);
547
548         /*
549          * Handle --upload-pack and friends. This is fire and forget...
550          * just warn if it fails.
551          */
552         if (strcmp(name, exec)) {
553                 r = set_helper_option(transport, "servpath", exec);
554                 if (r > 0)
555                         warning("Setting remote service path not supported by protocol.");
556                 else if (r < 0)
557                         warning("Invalid remote service path.");
558         }
559
560         if (data->connect)
561                 strbuf_addf(&cmdbuf, "connect %s\n", name);
562         else
563                 goto exit;
564
565         sendline(data, &cmdbuf);
566         recvline_fh(input, &cmdbuf, name);
567         if (!strcmp(cmdbuf.buf, "")) {
568                 data->no_disconnect_req = 1;
569                 if (debug)
570                         fprintf(stderr, "Debug: Smart transport connection "
571                                 "ready.\n");
572                 ret = 1;
573         } else if (!strcmp(cmdbuf.buf, "fallback")) {
574                 if (debug)
575                         fprintf(stderr, "Debug: Falling back to dumb "
576                                 "transport.\n");
577         } else
578                 die("Unknown response to connect: %s",
579                         cmdbuf.buf);
580
581 exit:
582         fclose(input);
583         return ret;
584 }
585
586 static int process_connect(struct transport *transport,
587                                      int for_push)
588 {
589         struct helper_data *data = transport->data;
590         const char *name;
591         const char *exec;
592
593         name = for_push ? "git-receive-pack" : "git-upload-pack";
594         if (for_push)
595                 exec = data->transport_options.receivepack;
596         else
597                 exec = data->transport_options.uploadpack;
598
599         return process_connect_service(transport, name, exec);
600 }
601
602 static int connect_helper(struct transport *transport, const char *name,
603                    const char *exec, int fd[2])
604 {
605         struct helper_data *data = transport->data;
606
607         /* Get_helper so connect is inited. */
608         get_helper(transport);
609         if (!data->connect)
610                 die("Operation not supported by protocol.");
611
612         if (!process_connect_service(transport, name, exec))
613                 die("Can't connect to subservice %s.", name);
614
615         fd[0] = data->helper->out;
616         fd[1] = data->helper->in;
617         return 0;
618 }
619
620 static int fetch(struct transport *transport,
621                  int nr_heads, struct ref **to_fetch)
622 {
623         struct helper_data *data = transport->data;
624         int i, count;
625
626         if (process_connect(transport, 0)) {
627                 do_take_over(transport);
628                 return transport->fetch(transport, nr_heads, to_fetch);
629         }
630
631         count = 0;
632         for (i = 0; i < nr_heads; i++)
633                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
634                         count++;
635
636         if (!count)
637                 return 0;
638
639         if (data->fetch)
640                 return fetch_with_fetch(transport, nr_heads, to_fetch);
641
642         if (data->import)
643                 return fetch_with_import(transport, nr_heads, to_fetch);
644
645         return -1;
646 }
647
648 static int push_update_ref_status(struct strbuf *buf,
649                                    struct ref **ref,
650                                    struct ref *remote_refs)
651 {
652         char *refname, *msg;
653         int status;
654
655         if (starts_with(buf->buf, "ok ")) {
656                 status = REF_STATUS_OK;
657                 refname = buf->buf + 3;
658         } else if (starts_with(buf->buf, "error ")) {
659                 status = REF_STATUS_REMOTE_REJECT;
660                 refname = buf->buf + 6;
661         } else
662                 die("expected ok/error, helper said '%s'", buf->buf);
663
664         msg = strchr(refname, ' ');
665         if (msg) {
666                 struct strbuf msg_buf = STRBUF_INIT;
667                 const char *end;
668
669                 *msg++ = '\0';
670                 if (!unquote_c_style(&msg_buf, msg, &end))
671                         msg = strbuf_detach(&msg_buf, NULL);
672                 else
673                         msg = xstrdup(msg);
674                 strbuf_release(&msg_buf);
675
676                 if (!strcmp(msg, "no match")) {
677                         status = REF_STATUS_NONE;
678                         free(msg);
679                         msg = NULL;
680                 }
681                 else if (!strcmp(msg, "up to date")) {
682                         status = REF_STATUS_UPTODATE;
683                         free(msg);
684                         msg = NULL;
685                 }
686                 else if (!strcmp(msg, "non-fast forward")) {
687                         status = REF_STATUS_REJECT_NONFASTFORWARD;
688                         free(msg);
689                         msg = NULL;
690                 }
691                 else if (!strcmp(msg, "already exists")) {
692                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
693                         free(msg);
694                         msg = NULL;
695                 }
696                 else if (!strcmp(msg, "fetch first")) {
697                         status = REF_STATUS_REJECT_FETCH_FIRST;
698                         free(msg);
699                         msg = NULL;
700                 }
701                 else if (!strcmp(msg, "needs force")) {
702                         status = REF_STATUS_REJECT_NEEDS_FORCE;
703                         free(msg);
704                         msg = NULL;
705                 }
706                 else if (!strcmp(msg, "stale info")) {
707                         status = REF_STATUS_REJECT_STALE;
708                         free(msg);
709                         msg = NULL;
710                 }
711         }
712
713         if (*ref)
714                 *ref = find_ref_by_name(*ref, refname);
715         if (!*ref)
716                 *ref = find_ref_by_name(remote_refs, refname);
717         if (!*ref) {
718                 warning("helper reported unexpected status of %s", refname);
719                 return 1;
720         }
721
722         if ((*ref)->status != REF_STATUS_NONE) {
723                 /*
724                  * Earlier, the ref was marked not to be pushed, so ignore the ref
725                  * status reported by the remote helper if the latter is 'no match'.
726                  */
727                 if (status == REF_STATUS_NONE)
728                         return 1;
729         }
730
731         (*ref)->status = status;
732         (*ref)->remote_status = msg;
733         return !(status == REF_STATUS_OK);
734 }
735
736 static void push_update_refs_status(struct helper_data *data,
737                                     struct ref *remote_refs)
738 {
739         struct strbuf buf = STRBUF_INIT;
740         struct ref *ref = remote_refs;
741         for (;;) {
742                 char *private;
743
744                 recvline(data, &buf);
745                 if (!buf.len)
746                         break;
747
748                 if (push_update_ref_status(&buf, &ref, remote_refs))
749                         continue;
750
751                 if (!data->refspecs || data->no_private_update)
752                         continue;
753
754                 /* propagate back the update to the remote namespace */
755                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
756                 if (!private)
757                         continue;
758                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
759                 free(private);
760         }
761         strbuf_release(&buf);
762 }
763
764 static int push_refs_with_push(struct transport *transport,
765                                struct ref *remote_refs, int flags)
766 {
767         int force_all = flags & TRANSPORT_PUSH_FORCE;
768         int mirror = flags & TRANSPORT_PUSH_MIRROR;
769         struct helper_data *data = transport->data;
770         struct strbuf buf = STRBUF_INIT;
771         struct ref *ref;
772         struct string_list cas_options = STRING_LIST_INIT_DUP;
773         struct string_list_item *cas_option;
774
775         get_helper(transport);
776         if (!data->push)
777                 return 1;
778
779         for (ref = remote_refs; ref; ref = ref->next) {
780                 if (!ref->peer_ref && !mirror)
781                         continue;
782
783                 /* Check for statuses set by set_ref_status_for_push() */
784                 switch (ref->status) {
785                 case REF_STATUS_REJECT_NONFASTFORWARD:
786                 case REF_STATUS_REJECT_STALE:
787                 case REF_STATUS_REJECT_ALREADY_EXISTS:
788                 case REF_STATUS_UPTODATE:
789                         continue;
790                 default:
791                         ; /* do nothing */
792                 }
793
794                 if (force_all)
795                         ref->force = 1;
796
797                 strbuf_addstr(&buf, "push ");
798                 if (!ref->deletion) {
799                         if (ref->force)
800                                 strbuf_addch(&buf, '+');
801                         if (ref->peer_ref)
802                                 strbuf_addstr(&buf, ref->peer_ref->name);
803                         else
804                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
805                 }
806                 strbuf_addch(&buf, ':');
807                 strbuf_addstr(&buf, ref->name);
808                 strbuf_addch(&buf, '\n');
809
810                 /*
811                  * The "--force-with-lease" options without explicit
812                  * values to expect have already been expanded into
813                  * the ref->old_sha1_expect[] field; we can ignore
814                  * transport->smart_options->cas altogether and instead
815                  * can enumerate them from the refs.
816                  */
817                 if (ref->expect_old_sha1) {
818                         struct strbuf cas = STRBUF_INIT;
819                         strbuf_addf(&cas, "%s:%s",
820                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
821                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
822                 }
823         }
824         if (buf.len == 0) {
825                 string_list_clear(&cas_options, 0);
826                 return 0;
827         }
828
829         standard_options(transport);
830         for_each_string_list_item(cas_option, &cas_options)
831                 set_helper_option(transport, "cas", cas_option->string);
832
833         if (flags & TRANSPORT_PUSH_DRY_RUN) {
834                 if (set_helper_option(transport, "dry-run", "true") != 0)
835                         die("helper %s does not support dry-run", data->name);
836         }
837
838         strbuf_addch(&buf, '\n');
839         sendline(data, &buf);
840         strbuf_release(&buf);
841
842         push_update_refs_status(data, remote_refs);
843         return 0;
844 }
845
846 static int push_refs_with_export(struct transport *transport,
847                 struct ref *remote_refs, int flags)
848 {
849         struct ref *ref;
850         struct child_process *helper, exporter;
851         struct helper_data *data = transport->data;
852         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
853         struct strbuf buf = STRBUF_INIT;
854
855         if (!data->refspecs)
856                 die("remote-helper doesn't support push; refspec needed");
857
858         if (flags & TRANSPORT_PUSH_DRY_RUN) {
859                 if (set_helper_option(transport, "dry-run", "true") != 0)
860                         die("helper %s does not support dry-run", data->name);
861         }
862
863         helper = get_helper(transport);
864
865         write_constant(helper->in, "export\n");
866
867         strbuf_reset(&buf);
868
869         for (ref = remote_refs; ref; ref = ref->next) {
870                 char *private;
871                 unsigned char sha1[20];
872
873                 if (ref->deletion)
874                         die("remote-helpers do not support ref deletion");
875
876                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
877                 if (private && !get_sha1(private, sha1)) {
878                         strbuf_addf(&buf, "^%s", private);
879                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
880                         hashcpy(ref->old_sha1, sha1);
881                 }
882                 free(private);
883
884                 if (ref->deletion)
885                         die("remote-helpers do not support ref deletion");
886
887                 if (ref->peer_ref) {
888                         if (strcmp(ref->peer_ref->name, ref->name))
889                                 die("remote-helpers do not support old:new syntax");
890                         string_list_append(&revlist_args, ref->peer_ref->name);
891                 }
892         }
893
894         if (get_exporter(transport, &exporter, &revlist_args))
895                 die("Couldn't run fast-export");
896
897         if (finish_command(&exporter))
898                 die("Error while running fast-export");
899         push_update_refs_status(data, remote_refs);
900         return 0;
901 }
902
903 static int push_refs(struct transport *transport,
904                 struct ref *remote_refs, int flags)
905 {
906         struct helper_data *data = transport->data;
907
908         if (process_connect(transport, 1)) {
909                 do_take_over(transport);
910                 return transport->push_refs(transport, remote_refs, flags);
911         }
912
913         if (!remote_refs) {
914                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
915                         "Perhaps you should specify a branch such as 'master'.\n");
916                 return 0;
917         }
918
919         if (data->push)
920                 return push_refs_with_push(transport, remote_refs, flags);
921
922         if (data->export)
923                 return push_refs_with_export(transport, remote_refs, flags);
924
925         return -1;
926 }
927
928
929 static int has_attribute(const char *attrs, const char *attr) {
930         int len;
931         if (!attrs)
932                 return 0;
933
934         len = strlen(attr);
935         for (;;) {
936                 const char *space = strchrnul(attrs, ' ');
937                 if (len == space - attrs && !strncmp(attrs, attr, len))
938                         return 1;
939                 if (!*space)
940                         return 0;
941                 attrs = space + 1;
942         }
943 }
944
945 static struct ref *get_refs_list(struct transport *transport, int for_push)
946 {
947         struct helper_data *data = transport->data;
948         struct child_process *helper;
949         struct ref *ret = NULL;
950         struct ref **tail = &ret;
951         struct ref *posn;
952         struct strbuf buf = STRBUF_INIT;
953
954         helper = get_helper(transport);
955
956         if (process_connect(transport, for_push)) {
957                 do_take_over(transport);
958                 return transport->get_refs_list(transport, for_push);
959         }
960
961         if (data->push && for_push)
962                 write_str_in_full(helper->in, "list for-push\n");
963         else
964                 write_str_in_full(helper->in, "list\n");
965
966         while (1) {
967                 char *eov, *eon;
968                 recvline(data, &buf);
969
970                 if (!*buf.buf)
971                         break;
972
973                 eov = strchr(buf.buf, ' ');
974                 if (!eov)
975                         die("Malformed response in ref list: %s", buf.buf);
976                 eon = strchr(eov + 1, ' ');
977                 *eov = '\0';
978                 if (eon)
979                         *eon = '\0';
980                 *tail = alloc_ref(eov + 1);
981                 if (buf.buf[0] == '@')
982                         (*tail)->symref = xstrdup(buf.buf + 1);
983                 else if (buf.buf[0] != '?')
984                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
985                 if (eon) {
986                         if (has_attribute(eon + 1, "unchanged")) {
987                                 (*tail)->status |= REF_STATUS_UPTODATE;
988                                 read_ref((*tail)->name, (*tail)->old_sha1);
989                         }
990                 }
991                 tail = &((*tail)->next);
992         }
993         if (debug)
994                 fprintf(stderr, "Debug: Read ref listing.\n");
995         strbuf_release(&buf);
996
997         for (posn = ret; posn; posn = posn->next)
998                 resolve_remote_symref(posn, ret);
999
1000         return ret;
1001 }
1002
1003 int transport_helper_init(struct transport *transport, const char *name)
1004 {
1005         struct helper_data *data = xcalloc(sizeof(*data), 1);
1006         data->name = name;
1007
1008         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1009                 debug = 1;
1010
1011         transport->data = data;
1012         transport->set_option = set_helper_option;
1013         transport->get_refs_list = get_refs_list;
1014         transport->fetch = fetch;
1015         transport->push_refs = push_refs;
1016         transport->disconnect = release_helper;
1017         transport->connect = connect_helper;
1018         transport->smart_options = &(data->transport_options);
1019         return 0;
1020 }
1021
1022 /*
1023  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1024  * buffer less), so attempt reads and writes with up to that size.
1025  */
1026 #define BUFFERSIZE 65536
1027 /* This should be enough to hold debugging message. */
1028 #define PBUFFERSIZE 8192
1029
1030 /* Print bidirectional transfer loop debug message. */
1031 __attribute__((format (printf, 1, 2)))
1032 static void transfer_debug(const char *fmt, ...)
1033 {
1034         va_list args;
1035         char msgbuf[PBUFFERSIZE];
1036         static int debug_enabled = -1;
1037
1038         if (debug_enabled < 0)
1039                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1040         if (!debug_enabled)
1041                 return;
1042
1043         va_start(args, fmt);
1044         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1045         va_end(args);
1046         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1047 }
1048
1049 /* Stream state: More data may be coming in this direction. */
1050 #define SSTATE_TRANSFERING 0
1051 /*
1052  * Stream state: No more data coming in this direction, flushing rest of
1053  * data.
1054  */
1055 #define SSTATE_FLUSHING 1
1056 /* Stream state: Transfer in this direction finished. */
1057 #define SSTATE_FINISHED 2
1058
1059 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1060 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1061 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1062
1063 /* Unidirectional transfer. */
1064 struct unidirectional_transfer {
1065         /* Source */
1066         int src;
1067         /* Destination */
1068         int dest;
1069         /* Is source socket? */
1070         int src_is_sock;
1071         /* Is destination socket? */
1072         int dest_is_sock;
1073         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1074         int state;
1075         /* Buffer. */
1076         char buf[BUFFERSIZE];
1077         /* Buffer used. */
1078         size_t bufuse;
1079         /* Name of source. */
1080         const char *src_name;
1081         /* Name of destination. */
1082         const char *dest_name;
1083 };
1084
1085 /* Closes the target (for writing) if transfer has finished. */
1086 static void udt_close_if_finished(struct unidirectional_transfer *t)
1087 {
1088         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1089                 t->state = SSTATE_FINISHED;
1090                 if (t->dest_is_sock)
1091                         shutdown(t->dest, SHUT_WR);
1092                 else
1093                         close(t->dest);
1094                 transfer_debug("Closed %s.", t->dest_name);
1095         }
1096 }
1097
1098 /*
1099  * Tries to read read data from source into buffer. If buffer is full,
1100  * no data is read. Returns 0 on success, -1 on error.
1101  */
1102 static int udt_do_read(struct unidirectional_transfer *t)
1103 {
1104         ssize_t bytes;
1105
1106         if (t->bufuse == BUFFERSIZE)
1107                 return 0;       /* No space for more. */
1108
1109         transfer_debug("%s is readable", t->src_name);
1110         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1111         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1112                 errno != EINTR) {
1113                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1114                 return -1;
1115         } else if (bytes == 0) {
1116                 transfer_debug("%s EOF (with %i bytes in buffer)",
1117                         t->src_name, (int)t->bufuse);
1118                 t->state = SSTATE_FLUSHING;
1119         } else if (bytes > 0) {
1120                 t->bufuse += bytes;
1121                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1122                         (int)bytes, t->src_name, (int)t->bufuse);
1123         }
1124         return 0;
1125 }
1126
1127 /* Tries to write data from buffer into destination. If buffer is empty,
1128  * no data is written. Returns 0 on success, -1 on error.
1129  */
1130 static int udt_do_write(struct unidirectional_transfer *t)
1131 {
1132         ssize_t bytes;
1133
1134         if (t->bufuse == 0)
1135                 return 0;       /* Nothing to write. */
1136
1137         transfer_debug("%s is writable", t->dest_name);
1138         bytes = xwrite(t->dest, t->buf, t->bufuse);
1139         if (bytes < 0 && errno != EWOULDBLOCK) {
1140                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1141                 return -1;
1142         } else if (bytes > 0) {
1143                 t->bufuse -= bytes;
1144                 if (t->bufuse)
1145                         memmove(t->buf, t->buf + bytes, t->bufuse);
1146                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1147                         (int)bytes, t->dest_name, (int)t->bufuse);
1148         }
1149         return 0;
1150 }
1151
1152
1153 /* State of bidirectional transfer loop. */
1154 struct bidirectional_transfer_state {
1155         /* Direction from program to git. */
1156         struct unidirectional_transfer ptg;
1157         /* Direction from git to program. */
1158         struct unidirectional_transfer gtp;
1159 };
1160
1161 static void *udt_copy_task_routine(void *udt)
1162 {
1163         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1164         while (t->state != SSTATE_FINISHED) {
1165                 if (STATE_NEEDS_READING(t->state))
1166                         if (udt_do_read(t))
1167                                 return NULL;
1168                 if (STATE_NEEDS_WRITING(t->state))
1169                         if (udt_do_write(t))
1170                                 return NULL;
1171                 if (STATE_NEEDS_CLOSING(t->state))
1172                         udt_close_if_finished(t);
1173         }
1174         return udt;     /* Just some non-NULL value. */
1175 }
1176
1177 #ifndef NO_PTHREADS
1178
1179 /*
1180  * Join thread, with appropriate errors on failure. Name is name for the
1181  * thread (for error messages). Returns 0 on success, 1 on failure.
1182  */
1183 static int tloop_join(pthread_t thread, const char *name)
1184 {
1185         int err;
1186         void *tret;
1187         err = pthread_join(thread, &tret);
1188         if (!tret) {
1189                 error("%s thread failed", name);
1190                 return 1;
1191         }
1192         if (err) {
1193                 error("%s thread failed to join: %s", name, strerror(err));
1194                 return 1;
1195         }
1196         return 0;
1197 }
1198
1199 /*
1200  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1201  * -1 on failure.
1202  */
1203 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1204 {
1205         pthread_t gtp_thread;
1206         pthread_t ptg_thread;
1207         int err;
1208         int ret = 0;
1209         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1210                 &s->gtp);
1211         if (err)
1212                 die("Can't start thread for copying data: %s", strerror(err));
1213         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1214                 &s->ptg);
1215         if (err)
1216                 die("Can't start thread for copying data: %s", strerror(err));
1217
1218         ret |= tloop_join(gtp_thread, "Git to program copy");
1219         ret |= tloop_join(ptg_thread, "Program to git copy");
1220         return ret;
1221 }
1222 #else
1223
1224 /* Close the source and target (for writing) for transfer. */
1225 static void udt_kill_transfer(struct unidirectional_transfer *t)
1226 {
1227         t->state = SSTATE_FINISHED;
1228         /*
1229          * Socket read end left open isn't a disaster if nobody
1230          * attempts to read from it (mingw compat headers do not
1231          * have SHUT_RD)...
1232          *
1233          * We can't fully close the socket since otherwise gtp
1234          * task would first close the socket it sends data to
1235          * while closing the ptg file descriptors.
1236          */
1237         if (!t->src_is_sock)
1238                 close(t->src);
1239         if (t->dest_is_sock)
1240                 shutdown(t->dest, SHUT_WR);
1241         else
1242                 close(t->dest);
1243 }
1244
1245 /*
1246  * Join process, with appropriate errors on failure. Name is name for the
1247  * process (for error messages). Returns 0 on success, 1 on failure.
1248  */
1249 static int tloop_join(pid_t pid, const char *name)
1250 {
1251         int tret;
1252         if (waitpid(pid, &tret, 0) < 0) {
1253                 error("%s process failed to wait: %s", name, strerror(errno));
1254                 return 1;
1255         }
1256         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1257                 error("%s process failed", name);
1258                 return 1;
1259         }
1260         return 0;
1261 }
1262
1263 /*
1264  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1265  * -1 on failure.
1266  */
1267 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1268 {
1269         pid_t pid1, pid2;
1270         int ret = 0;
1271
1272         /* Fork thread #1: git to program. */
1273         pid1 = fork();
1274         if (pid1 < 0)
1275                 die_errno("Can't start thread for copying data");
1276         else if (pid1 == 0) {
1277                 udt_kill_transfer(&s->ptg);
1278                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1279         }
1280
1281         /* Fork thread #2: program to git. */
1282         pid2 = fork();
1283         if (pid2 < 0)
1284                 die_errno("Can't start thread for copying data");
1285         else if (pid2 == 0) {
1286                 udt_kill_transfer(&s->gtp);
1287                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1288         }
1289
1290         /*
1291          * Close both streams in parent as to not interfere with
1292          * end of file detection and wait for both tasks to finish.
1293          */
1294         udt_kill_transfer(&s->gtp);
1295         udt_kill_transfer(&s->ptg);
1296         ret |= tloop_join(pid1, "Git to program copy");
1297         ret |= tloop_join(pid2, "Program to git copy");
1298         return ret;
1299 }
1300 #endif
1301
1302 /*
1303  * Copies data from stdin to output and from input to stdout simultaneously.
1304  * Additionally filtering through given filter. If filter is NULL, uses
1305  * identity filter.
1306  */
1307 int bidirectional_transfer_loop(int input, int output)
1308 {
1309         struct bidirectional_transfer_state state;
1310
1311         /* Fill the state fields. */
1312         state.ptg.src = input;
1313         state.ptg.dest = 1;
1314         state.ptg.src_is_sock = (input == output);
1315         state.ptg.dest_is_sock = 0;
1316         state.ptg.state = SSTATE_TRANSFERING;
1317         state.ptg.bufuse = 0;
1318         state.ptg.src_name = "remote input";
1319         state.ptg.dest_name = "stdout";
1320
1321         state.gtp.src = 0;
1322         state.gtp.dest = output;
1323         state.gtp.src_is_sock = 0;
1324         state.gtp.dest_is_sock = (input == output);
1325         state.gtp.state = SSTATE_TRANSFERING;
1326         state.gtp.bufuse = 0;
1327         state.gtp.src_name = "stdin";
1328         state.gtp.dest_name = "remote output";
1329
1330         return tloop_spawnwait_tasks(&state);
1331 }