Merge branch 'jk/submodule-fsck-loose-fixup'
[git] / transport-helper.c
1 #include "cache.h"
2 #include "transport.h"
3 #include "quote.h"
4 #include "run-command.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "revision.h"
8 #include "remote.h"
9 #include "string-list.h"
10 #include "thread-utils.h"
11 #include "sigchain.h"
12 #include "argv-array.h"
13 #include "refs.h"
14 #include "refspec.h"
15 #include "transport-internal.h"
16 #include "protocol.h"
17
18 static int debug;
19
20 struct helper_data {
21         const char *name;
22         struct child_process *helper;
23         FILE *out;
24         unsigned fetch : 1,
25                 import : 1,
26                 bidi_import : 1,
27                 export : 1,
28                 option : 1,
29                 push : 1,
30                 connect : 1,
31                 stateless_connect : 1,
32                 signed_tags : 1,
33                 check_connectivity : 1,
34                 no_disconnect_req : 1,
35                 no_private_update : 1;
36         char *export_marks;
37         char *import_marks;
38         /* These go from remote name (as in "list") to private name */
39         struct refspec rs;
40         /* Transport options for fetch-pack/send-pack (should one of
41          * those be invoked).
42          */
43         struct git_transport_options transport_options;
44 };
45
46 static void sendline(struct helper_data *helper, struct strbuf *buffer)
47 {
48         if (debug)
49                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
50         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
51                 die_errno("Full write to remote helper failed");
52 }
53
54 static int recvline_fh(FILE *helper, struct strbuf *buffer)
55 {
56         strbuf_reset(buffer);
57         if (debug)
58                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
59         if (strbuf_getline(buffer, helper) == EOF) {
60                 if (debug)
61                         fprintf(stderr, "Debug: Remote helper quit.\n");
62                 return 1;
63         }
64
65         if (debug)
66                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
67         return 0;
68 }
69
70 static int recvline(struct helper_data *helper, struct strbuf *buffer)
71 {
72         return recvline_fh(helper->out, buffer);
73 }
74
75 static void write_constant(int fd, const char *str)
76 {
77         if (debug)
78                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
79         if (write_in_full(fd, str, strlen(str)) < 0)
80                 die_errno("Full write to remote helper failed");
81 }
82
83 static const char *remove_ext_force(const char *url)
84 {
85         if (url) {
86                 const char *colon = strchr(url, ':');
87                 if (colon && colon[1] == ':')
88                         return colon + 2;
89         }
90         return url;
91 }
92
93 static void do_take_over(struct transport *transport)
94 {
95         struct helper_data *data;
96         data = (struct helper_data *)transport->data;
97         transport_take_over(transport, data->helper);
98         fclose(data->out);
99         free(data);
100 }
101
102 static void standard_options(struct transport *t);
103
104 static struct child_process *get_helper(struct transport *transport)
105 {
106         struct helper_data *data = transport->data;
107         struct strbuf buf = STRBUF_INIT;
108         struct child_process *helper;
109         int duped;
110         int code;
111
112         if (data->helper)
113                 return data->helper;
114
115         helper = xmalloc(sizeof(*helper));
116         child_process_init(helper);
117         helper->in = -1;
118         helper->out = -1;
119         helper->err = 0;
120         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
121         argv_array_push(&helper->args, transport->remote->name);
122         argv_array_push(&helper->args, remove_ext_force(transport->url));
123         helper->git_cmd = 0;
124         helper->silent_exec_failure = 1;
125
126         if (have_git_dir())
127                 argv_array_pushf(&helper->env_array, "%s=%s",
128                                  GIT_DIR_ENVIRONMENT, get_git_dir());
129
130         code = start_command(helper);
131         if (code < 0 && errno == ENOENT)
132                 die("Unable to find remote helper for '%s'", data->name);
133         else if (code != 0)
134                 exit(code);
135
136         data->helper = helper;
137         data->no_disconnect_req = 0;
138         refspec_init(&data->rs, REFSPEC_FETCH);
139
140         /*
141          * Open the output as FILE* so strbuf_getline_*() family of
142          * functions can be used.
143          * Do this with duped fd because fclose() will close the fd,
144          * and stuff like taking over will require the fd to remain.
145          */
146         duped = dup(helper->out);
147         if (duped < 0)
148                 die_errno("Can't dup helper output fd");
149         data->out = xfdopen(duped, "r");
150
151         write_constant(helper->in, "capabilities\n");
152
153         while (1) {
154                 const char *capname, *arg;
155                 int mandatory = 0;
156                 if (recvline(data, &buf))
157                         exit(128);
158
159                 if (!*buf.buf)
160                         break;
161
162                 if (*buf.buf == '*') {
163                         capname = buf.buf + 1;
164                         mandatory = 1;
165                 } else
166                         capname = buf.buf;
167
168                 if (debug)
169                         fprintf(stderr, "Debug: Got cap %s\n", capname);
170                 if (!strcmp(capname, "fetch"))
171                         data->fetch = 1;
172                 else if (!strcmp(capname, "option"))
173                         data->option = 1;
174                 else if (!strcmp(capname, "push"))
175                         data->push = 1;
176                 else if (!strcmp(capname, "import"))
177                         data->import = 1;
178                 else if (!strcmp(capname, "bidi-import"))
179                         data->bidi_import = 1;
180                 else if (!strcmp(capname, "export"))
181                         data->export = 1;
182                 else if (!strcmp(capname, "check-connectivity"))
183                         data->check_connectivity = 1;
184                 else if (skip_prefix(capname, "refspec ", &arg)) {
185                         refspec_append(&data->rs, arg);
186                 } else if (!strcmp(capname, "connect")) {
187                         data->connect = 1;
188                 } else if (!strcmp(capname, "stateless-connect")) {
189                         data->stateless_connect = 1;
190                 } else if (!strcmp(capname, "signed-tags")) {
191                         data->signed_tags = 1;
192                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
193                         data->export_marks = xstrdup(arg);
194                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
195                         data->import_marks = xstrdup(arg);
196                 } else if (starts_with(capname, "no-private-update")) {
197                         data->no_private_update = 1;
198                 } else if (mandatory) {
199                         die("Unknown mandatory capability %s. This remote "
200                             "helper probably needs newer version of Git.",
201                             capname);
202                 }
203         }
204         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
205                 warning("This remote helper should implement refspec capability.");
206         }
207         strbuf_release(&buf);
208         if (debug)
209                 fprintf(stderr, "Debug: Capabilities complete.\n");
210         standard_options(transport);
211         return data->helper;
212 }
213
214 static int disconnect_helper(struct transport *transport)
215 {
216         struct helper_data *data = transport->data;
217         int res = 0;
218
219         if (data->helper) {
220                 if (debug)
221                         fprintf(stderr, "Debug: Disconnecting.\n");
222                 if (!data->no_disconnect_req) {
223                         /*
224                          * Ignore write errors; there's nothing we can do,
225                          * since we're about to close the pipe anyway. And the
226                          * most likely error is EPIPE due to the helper dying
227                          * to report an error itself.
228                          */
229                         sigchain_push(SIGPIPE, SIG_IGN);
230                         xwrite(data->helper->in, "\n", 1);
231                         sigchain_pop(SIGPIPE);
232                 }
233                 close(data->helper->in);
234                 close(data->helper->out);
235                 fclose(data->out);
236                 res = finish_command(data->helper);
237                 FREE_AND_NULL(data->helper);
238         }
239         return res;
240 }
241
242 static const char *unsupported_options[] = {
243         TRANS_OPT_UPLOADPACK,
244         TRANS_OPT_RECEIVEPACK,
245         TRANS_OPT_THIN,
246         TRANS_OPT_KEEP
247         };
248
249 static const char *boolean_options[] = {
250         TRANS_OPT_THIN,
251         TRANS_OPT_KEEP,
252         TRANS_OPT_FOLLOWTAGS,
253         TRANS_OPT_DEEPEN_RELATIVE
254         };
255
256 static int strbuf_set_helper_option(struct helper_data *data,
257                                     struct strbuf *buf)
258 {
259         int ret;
260
261         sendline(data, buf);
262         if (recvline(data, buf))
263                 exit(128);
264
265         if (!strcmp(buf->buf, "ok"))
266                 ret = 0;
267         else if (starts_with(buf->buf, "error"))
268                 ret = -1;
269         else if (!strcmp(buf->buf, "unsupported"))
270                 ret = 1;
271         else {
272                 warning("%s unexpectedly said: '%s'", data->name, buf->buf);
273                 ret = 1;
274         }
275         return ret;
276 }
277
278 static int string_list_set_helper_option(struct helper_data *data,
279                                          const char *name,
280                                          struct string_list *list)
281 {
282         struct strbuf buf = STRBUF_INIT;
283         int i, ret = 0;
284
285         for (i = 0; i < list->nr; i++) {
286                 strbuf_addf(&buf, "option %s ", name);
287                 quote_c_style(list->items[i].string, &buf, NULL, 0);
288                 strbuf_addch(&buf, '\n');
289
290                 if ((ret = strbuf_set_helper_option(data, &buf)))
291                         break;
292                 strbuf_reset(&buf);
293         }
294         strbuf_release(&buf);
295         return ret;
296 }
297
298 static int set_helper_option(struct transport *transport,
299                           const char *name, const char *value)
300 {
301         struct helper_data *data = transport->data;
302         struct strbuf buf = STRBUF_INIT;
303         int i, ret, is_bool = 0;
304
305         get_helper(transport);
306
307         if (!data->option)
308                 return 1;
309
310         if (!strcmp(name, "deepen-not"))
311                 return string_list_set_helper_option(data, name,
312                                                      (struct string_list *)value);
313
314         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
315                 if (!strcmp(name, unsupported_options[i]))
316                         return 1;
317         }
318
319         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
320                 if (!strcmp(name, boolean_options[i])) {
321                         is_bool = 1;
322                         break;
323                 }
324         }
325
326         strbuf_addf(&buf, "option %s ", name);
327         if (is_bool)
328                 strbuf_addstr(&buf, value ? "true" : "false");
329         else
330                 quote_c_style(value, &buf, NULL, 0);
331         strbuf_addch(&buf, '\n');
332
333         ret = strbuf_set_helper_option(data, &buf);
334         strbuf_release(&buf);
335         return ret;
336 }
337
338 static void standard_options(struct transport *t)
339 {
340         char buf[16];
341         int v = t->verbose;
342
343         set_helper_option(t, "progress", t->progress ? "true" : "false");
344
345         xsnprintf(buf, sizeof(buf), "%d", v + 1);
346         set_helper_option(t, "verbosity", buf);
347
348         switch (t->family) {
349         case TRANSPORT_FAMILY_ALL:
350                 /*
351                  * this is already the default,
352                  * do not break old remote helpers by setting "all" here
353                  */
354                 break;
355         case TRANSPORT_FAMILY_IPV4:
356                 set_helper_option(t, "family", "ipv4");
357                 break;
358         case TRANSPORT_FAMILY_IPV6:
359                 set_helper_option(t, "family", "ipv6");
360                 break;
361         }
362 }
363
364 static int release_helper(struct transport *transport)
365 {
366         int res = 0;
367         struct helper_data *data = transport->data;
368         refspec_clear(&data->rs);
369         res = disconnect_helper(transport);
370         free(transport->data);
371         return res;
372 }
373
374 static int fetch_with_fetch(struct transport *transport,
375                             int nr_heads, struct ref **to_fetch)
376 {
377         struct helper_data *data = transport->data;
378         int i;
379         struct strbuf buf = STRBUF_INIT;
380
381         for (i = 0; i < nr_heads; i++) {
382                 const struct ref *posn = to_fetch[i];
383                 if (posn->status & REF_STATUS_UPTODATE)
384                         continue;
385
386                 strbuf_addf(&buf, "fetch %s %s\n",
387                             oid_to_hex(&posn->old_oid),
388                             posn->symref ? posn->symref : posn->name);
389         }
390
391         strbuf_addch(&buf, '\n');
392         sendline(data, &buf);
393
394         while (1) {
395                 if (recvline(data, &buf))
396                         exit(128);
397
398                 if (starts_with(buf.buf, "lock ")) {
399                         const char *name = buf.buf + 5;
400                         if (transport->pack_lockfile)
401                                 warning("%s also locked %s", data->name, name);
402                         else
403                                 transport->pack_lockfile = xstrdup(name);
404                 }
405                 else if (data->check_connectivity &&
406                          data->transport_options.check_self_contained_and_connected &&
407                          !strcmp(buf.buf, "connectivity-ok"))
408                         data->transport_options.self_contained_and_connected = 1;
409                 else if (!buf.len)
410                         break;
411                 else
412                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
413         }
414         strbuf_release(&buf);
415         return 0;
416 }
417
418 static int get_importer(struct transport *transport, struct child_process *fastimport)
419 {
420         struct child_process *helper = get_helper(transport);
421         struct helper_data *data = transport->data;
422         int cat_blob_fd, code;
423         child_process_init(fastimport);
424         fastimport->in = helper->out;
425         argv_array_push(&fastimport->args, "fast-import");
426         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
427
428         if (data->bidi_import) {
429                 cat_blob_fd = xdup(helper->in);
430                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
431         }
432         fastimport->git_cmd = 1;
433
434         code = start_command(fastimport);
435         return code;
436 }
437
438 static int get_exporter(struct transport *transport,
439                         struct child_process *fastexport,
440                         struct string_list *revlist_args)
441 {
442         struct helper_data *data = transport->data;
443         struct child_process *helper = get_helper(transport);
444         int i;
445
446         child_process_init(fastexport);
447
448         /* we need to duplicate helper->in because we want to use it after
449          * fastexport is done with it. */
450         fastexport->out = dup(helper->in);
451         argv_array_push(&fastexport->args, "fast-export");
452         argv_array_push(&fastexport->args, "--use-done-feature");
453         argv_array_push(&fastexport->args, data->signed_tags ?
454                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
455         if (data->export_marks)
456                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
457         if (data->import_marks)
458                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
459
460         for (i = 0; i < revlist_args->nr; i++)
461                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
462
463         fastexport->git_cmd = 1;
464         return start_command(fastexport);
465 }
466
467 static int fetch_with_import(struct transport *transport,
468                              int nr_heads, struct ref **to_fetch)
469 {
470         struct child_process fastimport;
471         struct helper_data *data = transport->data;
472         int i;
473         struct ref *posn;
474         struct strbuf buf = STRBUF_INIT;
475
476         get_helper(transport);
477
478         if (get_importer(transport, &fastimport))
479                 die("Couldn't run fast-import");
480
481         for (i = 0; i < nr_heads; i++) {
482                 posn = to_fetch[i];
483                 if (posn->status & REF_STATUS_UPTODATE)
484                         continue;
485
486                 strbuf_addf(&buf, "import %s\n",
487                             posn->symref ? posn->symref : posn->name);
488                 sendline(data, &buf);
489                 strbuf_reset(&buf);
490         }
491
492         write_constant(data->helper->in, "\n");
493         /*
494          * remote-helpers that advertise the bidi-import capability are required to
495          * buffer the complete batch of import commands until this newline before
496          * sending data to fast-import.
497          * These helpers read back data from fast-import on their stdin, which could
498          * be mixed with import commands, otherwise.
499          */
500
501         if (finish_command(&fastimport))
502                 die("Error while running fast-import");
503
504         /*
505          * The fast-import stream of a remote helper that advertises
506          * the "refspec" capability writes to the refs named after the
507          * right hand side of the first refspec matching each ref we
508          * were fetching.
509          *
510          * (If no "refspec" capability was specified, for historical
511          * reasons we default to the equivalent of *:*.)
512          *
513          * Store the result in to_fetch[i].old_sha1.  Callers such
514          * as "git fetch" can use the value to write feedback to the
515          * terminal, populate FETCH_HEAD, and determine what new value
516          * should be written to peer_ref if the update is a
517          * fast-forward or this is a forced update.
518          */
519         for (i = 0; i < nr_heads; i++) {
520                 char *private, *name;
521                 posn = to_fetch[i];
522                 if (posn->status & REF_STATUS_UPTODATE)
523                         continue;
524                 name = posn->symref ? posn->symref : posn->name;
525                 if (data->rs.nr)
526                         private = apply_refspecs(&data->rs, name);
527                 else
528                         private = xstrdup(name);
529                 if (private) {
530                         if (read_ref(private, &posn->old_oid) < 0)
531                                 die("Could not read ref %s", private);
532                         free(private);
533                 }
534         }
535         strbuf_release(&buf);
536         return 0;
537 }
538
539 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
540 {
541         struct helper_data *data = transport->data;
542         int ret = 0;
543         int duped;
544         FILE *input;
545         struct child_process *helper;
546
547         helper = get_helper(transport);
548
549         /*
550          * Yes, dup the pipe another time, as we need unbuffered version
551          * of input pipe as FILE*. fclose() closes the underlying fd and
552          * stream buffering only can be changed before first I/O operation
553          * on it.
554          */
555         duped = dup(helper->out);
556         if (duped < 0)
557                 die_errno("Can't dup helper output fd");
558         input = xfdopen(duped, "r");
559         setvbuf(input, NULL, _IONBF, 0);
560
561         sendline(data, cmdbuf);
562         if (recvline_fh(input, cmdbuf))
563                 exit(128);
564
565         if (!strcmp(cmdbuf->buf, "")) {
566                 data->no_disconnect_req = 1;
567                 if (debug)
568                         fprintf(stderr, "Debug: Smart transport connection "
569                                 "ready.\n");
570                 ret = 1;
571         } else if (!strcmp(cmdbuf->buf, "fallback")) {
572                 if (debug)
573                         fprintf(stderr, "Debug: Falling back to dumb "
574                                 "transport.\n");
575         } else {
576                 die("Unknown response to connect: %s",
577                         cmdbuf->buf);
578         }
579
580         fclose(input);
581         return ret;
582 }
583
584 static int process_connect_service(struct transport *transport,
585                                    const char *name, const char *exec)
586 {
587         struct helper_data *data = transport->data;
588         struct strbuf cmdbuf = STRBUF_INIT;
589         int ret = 0;
590
591         /*
592          * Handle --upload-pack and friends. This is fire and forget...
593          * just warn if it fails.
594          */
595         if (strcmp(name, exec)) {
596                 int r = set_helper_option(transport, "servpath", exec);
597                 if (r > 0)
598                         warning("Setting remote service path not supported by protocol.");
599                 else if (r < 0)
600                         warning("Invalid remote service path.");
601         }
602
603         if (data->connect) {
604                 strbuf_addf(&cmdbuf, "connect %s\n", name);
605                 ret = run_connect(transport, &cmdbuf);
606         } else if (data->stateless_connect &&
607                    (get_protocol_version_config() == protocol_v2) &&
608                    !strcmp("git-upload-pack", name)) {
609                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
610                 ret = run_connect(transport, &cmdbuf);
611                 if (ret)
612                         transport->stateless_rpc = 1;
613         }
614
615         strbuf_release(&cmdbuf);
616         return ret;
617 }
618
619 static int process_connect(struct transport *transport,
620                                      int for_push)
621 {
622         struct helper_data *data = transport->data;
623         const char *name;
624         const char *exec;
625
626         name = for_push ? "git-receive-pack" : "git-upload-pack";
627         if (for_push)
628                 exec = data->transport_options.receivepack;
629         else
630                 exec = data->transport_options.uploadpack;
631
632         return process_connect_service(transport, name, exec);
633 }
634
635 static int connect_helper(struct transport *transport, const char *name,
636                    const char *exec, int fd[2])
637 {
638         struct helper_data *data = transport->data;
639
640         /* Get_helper so connect is inited. */
641         get_helper(transport);
642         if (!data->connect)
643                 die("Operation not supported by protocol.");
644
645         if (!process_connect_service(transport, name, exec))
646                 die("Can't connect to subservice %s.", name);
647
648         fd[0] = data->helper->out;
649         fd[1] = data->helper->in;
650         return 0;
651 }
652
653 static int fetch(struct transport *transport,
654                  int nr_heads, struct ref **to_fetch)
655 {
656         struct helper_data *data = transport->data;
657         int i, count;
658
659         if (process_connect(transport, 0)) {
660                 do_take_over(transport);
661                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
662         }
663
664         count = 0;
665         for (i = 0; i < nr_heads; i++)
666                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
667                         count++;
668
669         if (!count)
670                 return 0;
671
672         if (data->check_connectivity &&
673             data->transport_options.check_self_contained_and_connected)
674                 set_helper_option(transport, "check-connectivity", "true");
675
676         if (transport->cloning)
677                 set_helper_option(transport, "cloning", "true");
678
679         if (data->transport_options.update_shallow)
680                 set_helper_option(transport, "update-shallow", "true");
681
682         if (data->transport_options.filter_options.choice)
683                 set_helper_option(
684                         transport, "filter",
685                         data->transport_options.filter_options.filter_spec);
686
687         if (data->fetch)
688                 return fetch_with_fetch(transport, nr_heads, to_fetch);
689
690         if (data->import)
691                 return fetch_with_import(transport, nr_heads, to_fetch);
692
693         return -1;
694 }
695
696 static int push_update_ref_status(struct strbuf *buf,
697                                    struct ref **ref,
698                                    struct ref *remote_refs)
699 {
700         char *refname, *msg;
701         int status, forced = 0;
702
703         if (starts_with(buf->buf, "ok ")) {
704                 status = REF_STATUS_OK;
705                 refname = buf->buf + 3;
706         } else if (starts_with(buf->buf, "error ")) {
707                 status = REF_STATUS_REMOTE_REJECT;
708                 refname = buf->buf + 6;
709         } else
710                 die("expected ok/error, helper said '%s'", buf->buf);
711
712         msg = strchr(refname, ' ');
713         if (msg) {
714                 struct strbuf msg_buf = STRBUF_INIT;
715                 const char *end;
716
717                 *msg++ = '\0';
718                 if (!unquote_c_style(&msg_buf, msg, &end))
719                         msg = strbuf_detach(&msg_buf, NULL);
720                 else
721                         msg = xstrdup(msg);
722                 strbuf_release(&msg_buf);
723
724                 if (!strcmp(msg, "no match")) {
725                         status = REF_STATUS_NONE;
726                         FREE_AND_NULL(msg);
727                 }
728                 else if (!strcmp(msg, "up to date")) {
729                         status = REF_STATUS_UPTODATE;
730                         FREE_AND_NULL(msg);
731                 }
732                 else if (!strcmp(msg, "non-fast forward")) {
733                         status = REF_STATUS_REJECT_NONFASTFORWARD;
734                         FREE_AND_NULL(msg);
735                 }
736                 else if (!strcmp(msg, "already exists")) {
737                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
738                         FREE_AND_NULL(msg);
739                 }
740                 else if (!strcmp(msg, "fetch first")) {
741                         status = REF_STATUS_REJECT_FETCH_FIRST;
742                         FREE_AND_NULL(msg);
743                 }
744                 else if (!strcmp(msg, "needs force")) {
745                         status = REF_STATUS_REJECT_NEEDS_FORCE;
746                         FREE_AND_NULL(msg);
747                 }
748                 else if (!strcmp(msg, "stale info")) {
749                         status = REF_STATUS_REJECT_STALE;
750                         FREE_AND_NULL(msg);
751                 }
752                 else if (!strcmp(msg, "forced update")) {
753                         forced = 1;
754                         FREE_AND_NULL(msg);
755                 }
756         }
757
758         if (*ref)
759                 *ref = find_ref_by_name(*ref, refname);
760         if (!*ref)
761                 *ref = find_ref_by_name(remote_refs, refname);
762         if (!*ref) {
763                 warning("helper reported unexpected status of %s", refname);
764                 return 1;
765         }
766
767         if ((*ref)->status != REF_STATUS_NONE) {
768                 /*
769                  * Earlier, the ref was marked not to be pushed, so ignore the ref
770                  * status reported by the remote helper if the latter is 'no match'.
771                  */
772                 if (status == REF_STATUS_NONE)
773                         return 1;
774         }
775
776         (*ref)->status = status;
777         (*ref)->forced_update |= forced;
778         (*ref)->remote_status = msg;
779         return !(status == REF_STATUS_OK);
780 }
781
782 static int push_update_refs_status(struct helper_data *data,
783                                     struct ref *remote_refs,
784                                     int flags)
785 {
786         struct strbuf buf = STRBUF_INIT;
787         struct ref *ref = remote_refs;
788         int ret = 0;
789
790         for (;;) {
791                 char *private;
792
793                 if (recvline(data, &buf)) {
794                         ret = 1;
795                         break;
796                 }
797
798                 if (!buf.len)
799                         break;
800
801                 if (push_update_ref_status(&buf, &ref, remote_refs))
802                         continue;
803
804                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
805                         continue;
806
807                 /* propagate back the update to the remote namespace */
808                 private = apply_refspecs(&data->rs, ref->name);
809                 if (!private)
810                         continue;
811                 update_ref("update by helper", private, &ref->new_oid, NULL,
812                            0, 0);
813                 free(private);
814         }
815         strbuf_release(&buf);
816         return ret;
817 }
818
819 static void set_common_push_options(struct transport *transport,
820                                    const char *name, int flags)
821 {
822         if (flags & TRANSPORT_PUSH_DRY_RUN) {
823                 if (set_helper_option(transport, "dry-run", "true") != 0)
824                         die("helper %s does not support dry-run", name);
825         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
826                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
827                         die("helper %s does not support --signed", name);
828         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
829                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
830                         die("helper %s does not support --signed=if-asked", name);
831         }
832
833         if (flags & TRANSPORT_PUSH_OPTIONS) {
834                 struct string_list_item *item;
835                 for_each_string_list_item(item, transport->push_options)
836                         if (set_helper_option(transport, "push-option", item->string) != 0)
837                                 die("helper %s does not support 'push-option'", name);
838         }
839 }
840
841 static int push_refs_with_push(struct transport *transport,
842                                struct ref *remote_refs, int flags)
843 {
844         int force_all = flags & TRANSPORT_PUSH_FORCE;
845         int mirror = flags & TRANSPORT_PUSH_MIRROR;
846         struct helper_data *data = transport->data;
847         struct strbuf buf = STRBUF_INIT;
848         struct ref *ref;
849         struct string_list cas_options = STRING_LIST_INIT_DUP;
850         struct string_list_item *cas_option;
851
852         get_helper(transport);
853         if (!data->push)
854                 return 1;
855
856         for (ref = remote_refs; ref; ref = ref->next) {
857                 if (!ref->peer_ref && !mirror)
858                         continue;
859
860                 /* Check for statuses set by set_ref_status_for_push() */
861                 switch (ref->status) {
862                 case REF_STATUS_REJECT_NONFASTFORWARD:
863                 case REF_STATUS_REJECT_STALE:
864                 case REF_STATUS_REJECT_ALREADY_EXISTS:
865                 case REF_STATUS_UPTODATE:
866                         continue;
867                 default:
868                         ; /* do nothing */
869                 }
870
871                 if (force_all)
872                         ref->force = 1;
873
874                 strbuf_addstr(&buf, "push ");
875                 if (!ref->deletion) {
876                         if (ref->force)
877                                 strbuf_addch(&buf, '+');
878                         if (ref->peer_ref)
879                                 strbuf_addstr(&buf, ref->peer_ref->name);
880                         else
881                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
882                 }
883                 strbuf_addch(&buf, ':');
884                 strbuf_addstr(&buf, ref->name);
885                 strbuf_addch(&buf, '\n');
886
887                 /*
888                  * The "--force-with-lease" options without explicit
889                  * values to expect have already been expanded into
890                  * the ref->old_oid_expect[] field; we can ignore
891                  * transport->smart_options->cas altogether and instead
892                  * can enumerate them from the refs.
893                  */
894                 if (ref->expect_old_sha1) {
895                         struct strbuf cas = STRBUF_INIT;
896                         strbuf_addf(&cas, "%s:%s",
897                                     ref->name, oid_to_hex(&ref->old_oid_expect));
898                         string_list_append_nodup(&cas_options,
899                                                  strbuf_detach(&cas, NULL));
900                 }
901         }
902         if (buf.len == 0) {
903                 string_list_clear(&cas_options, 0);
904                 return 0;
905         }
906
907         for_each_string_list_item(cas_option, &cas_options)
908                 set_helper_option(transport, "cas", cas_option->string);
909         set_common_push_options(transport, data->name, flags);
910
911         strbuf_addch(&buf, '\n');
912         sendline(data, &buf);
913         strbuf_release(&buf);
914         string_list_clear(&cas_options, 0);
915
916         return push_update_refs_status(data, remote_refs, flags);
917 }
918
919 static int push_refs_with_export(struct transport *transport,
920                 struct ref *remote_refs, int flags)
921 {
922         struct ref *ref;
923         struct child_process *helper, exporter;
924         struct helper_data *data = transport->data;
925         struct string_list revlist_args = STRING_LIST_INIT_DUP;
926         struct strbuf buf = STRBUF_INIT;
927
928         if (!data->rs.nr)
929                 die("remote-helper doesn't support push; refspec needed");
930
931         set_common_push_options(transport, data->name, flags);
932         if (flags & TRANSPORT_PUSH_FORCE) {
933                 if (set_helper_option(transport, "force", "true") != 0)
934                         warning("helper %s does not support 'force'", data->name);
935         }
936
937         helper = get_helper(transport);
938
939         write_constant(helper->in, "export\n");
940
941         for (ref = remote_refs; ref; ref = ref->next) {
942                 char *private;
943                 struct object_id oid;
944
945                 private = apply_refspecs(&data->rs, ref->name);
946                 if (private && !get_oid(private, &oid)) {
947                         strbuf_addf(&buf, "^%s", private);
948                         string_list_append_nodup(&revlist_args,
949                                                  strbuf_detach(&buf, NULL));
950                         oidcpy(&ref->old_oid, &oid);
951                 }
952                 free(private);
953
954                 if (ref->peer_ref) {
955                         if (strcmp(ref->name, ref->peer_ref->name)) {
956                                 if (!ref->deletion) {
957                                         const char *name;
958                                         int flag;
959
960                                         /* Follow symbolic refs (mainly for HEAD). */
961                                         name = resolve_ref_unsafe(ref->peer_ref->name,
962                                                                   RESOLVE_REF_READING,
963                                                                   &oid, &flag);
964                                         if (!name || !(flag & REF_ISSYMREF))
965                                                 name = ref->peer_ref->name;
966
967                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
968                                 } else
969                                         strbuf_addf(&buf, ":%s", ref->name);
970
971                                 string_list_append(&revlist_args, "--refspec");
972                                 string_list_append(&revlist_args, buf.buf);
973                                 strbuf_release(&buf);
974                         }
975                         if (!ref->deletion)
976                                 string_list_append(&revlist_args, ref->peer_ref->name);
977                 }
978         }
979
980         if (get_exporter(transport, &exporter, &revlist_args))
981                 die("Couldn't run fast-export");
982
983         string_list_clear(&revlist_args, 1);
984
985         if (finish_command(&exporter))
986                 die("Error while running fast-export");
987         if (push_update_refs_status(data, remote_refs, flags))
988                 return 1;
989
990         if (data->export_marks) {
991                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
992                 rename(buf.buf, data->export_marks);
993                 strbuf_release(&buf);
994         }
995
996         return 0;
997 }
998
999 static int push_refs(struct transport *transport,
1000                 struct ref *remote_refs, int flags)
1001 {
1002         struct helper_data *data = transport->data;
1003
1004         if (process_connect(transport, 1)) {
1005                 do_take_over(transport);
1006                 return transport->vtable->push_refs(transport, remote_refs, flags);
1007         }
1008
1009         if (!remote_refs) {
1010                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
1011                         "Perhaps you should specify a branch such as 'master'.\n");
1012                 return 0;
1013         }
1014
1015         if (data->push)
1016                 return push_refs_with_push(transport, remote_refs, flags);
1017
1018         if (data->export)
1019                 return push_refs_with_export(transport, remote_refs, flags);
1020
1021         return -1;
1022 }
1023
1024
1025 static int has_attribute(const char *attrs, const char *attr) {
1026         int len;
1027         if (!attrs)
1028                 return 0;
1029
1030         len = strlen(attr);
1031         for (;;) {
1032                 const char *space = strchrnul(attrs, ' ');
1033                 if (len == space - attrs && !strncmp(attrs, attr, len))
1034                         return 1;
1035                 if (!*space)
1036                         return 0;
1037                 attrs = space + 1;
1038         }
1039 }
1040
1041 static struct ref *get_refs_list(struct transport *transport, int for_push,
1042                                  const struct argv_array *ref_prefixes)
1043 {
1044         struct helper_data *data = transport->data;
1045         struct child_process *helper;
1046         struct ref *ret = NULL;
1047         struct ref **tail = &ret;
1048         struct ref *posn;
1049         struct strbuf buf = STRBUF_INIT;
1050
1051         helper = get_helper(transport);
1052
1053         if (process_connect(transport, for_push)) {
1054                 do_take_over(transport);
1055                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1056         }
1057
1058         if (data->push && for_push)
1059                 write_str_in_full(helper->in, "list for-push\n");
1060         else
1061                 write_str_in_full(helper->in, "list\n");
1062
1063         while (1) {
1064                 char *eov, *eon;
1065                 if (recvline(data, &buf))
1066                         exit(128);
1067
1068                 if (!*buf.buf)
1069                         break;
1070
1071                 eov = strchr(buf.buf, ' ');
1072                 if (!eov)
1073                         die("Malformed response in ref list: %s", buf.buf);
1074                 eon = strchr(eov + 1, ' ');
1075                 *eov = '\0';
1076                 if (eon)
1077                         *eon = '\0';
1078                 *tail = alloc_ref(eov + 1);
1079                 if (buf.buf[0] == '@')
1080                         (*tail)->symref = xstrdup(buf.buf + 1);
1081                 else if (buf.buf[0] != '?')
1082                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1083                 if (eon) {
1084                         if (has_attribute(eon + 1, "unchanged")) {
1085                                 (*tail)->status |= REF_STATUS_UPTODATE;
1086                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1087                                         die(_("Could not read ref %s"),
1088                                             (*tail)->name);
1089                         }
1090                 }
1091                 tail = &((*tail)->next);
1092         }
1093         if (debug)
1094                 fprintf(stderr, "Debug: Read ref listing.\n");
1095         strbuf_release(&buf);
1096
1097         for (posn = ret; posn; posn = posn->next)
1098                 resolve_remote_symref(posn, ret);
1099
1100         return ret;
1101 }
1102
1103 static struct transport_vtable vtable = {
1104         set_helper_option,
1105         get_refs_list,
1106         fetch,
1107         push_refs,
1108         connect_helper,
1109         release_helper
1110 };
1111
1112 int transport_helper_init(struct transport *transport, const char *name)
1113 {
1114         struct helper_data *data = xcalloc(1, sizeof(*data));
1115         data->name = name;
1116
1117         transport_check_allowed(name);
1118
1119         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1120                 debug = 1;
1121
1122         transport->data = data;
1123         transport->vtable = &vtable;
1124         transport->smart_options = &(data->transport_options);
1125         return 0;
1126 }
1127
1128 /*
1129  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1130  * buffer less), so attempt reads and writes with up to that size.
1131  */
1132 #define BUFFERSIZE 65536
1133 /* This should be enough to hold debugging message. */
1134 #define PBUFFERSIZE 8192
1135
1136 /* Print bidirectional transfer loop debug message. */
1137 __attribute__((format (printf, 1, 2)))
1138 static void transfer_debug(const char *fmt, ...)
1139 {
1140         /*
1141          * NEEDSWORK: This function is sometimes used from multiple threads, and
1142          * we end up using debug_enabled racily. That "should not matter" since
1143          * we always write the same value, but it's still wrong. This function
1144          * is listed in .tsan-suppressions for the time being.
1145          */
1146
1147         va_list args;
1148         char msgbuf[PBUFFERSIZE];
1149         static int debug_enabled = -1;
1150
1151         if (debug_enabled < 0)
1152                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1153         if (!debug_enabled)
1154                 return;
1155
1156         va_start(args, fmt);
1157         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1158         va_end(args);
1159         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1160 }
1161
1162 /* Stream state: More data may be coming in this direction. */
1163 #define SSTATE_TRANSFERRING 0
1164 /*
1165  * Stream state: No more data coming in this direction, flushing rest of
1166  * data.
1167  */
1168 #define SSTATE_FLUSHING 1
1169 /* Stream state: Transfer in this direction finished. */
1170 #define SSTATE_FINISHED 2
1171
1172 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1173 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1174 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1175
1176 /* Unidirectional transfer. */
1177 struct unidirectional_transfer {
1178         /* Source */
1179         int src;
1180         /* Destination */
1181         int dest;
1182         /* Is source socket? */
1183         int src_is_sock;
1184         /* Is destination socket? */
1185         int dest_is_sock;
1186         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1187         int state;
1188         /* Buffer. */
1189         char buf[BUFFERSIZE];
1190         /* Buffer used. */
1191         size_t bufuse;
1192         /* Name of source. */
1193         const char *src_name;
1194         /* Name of destination. */
1195         const char *dest_name;
1196 };
1197
1198 /* Closes the target (for writing) if transfer has finished. */
1199 static void udt_close_if_finished(struct unidirectional_transfer *t)
1200 {
1201         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1202                 t->state = SSTATE_FINISHED;
1203                 if (t->dest_is_sock)
1204                         shutdown(t->dest, SHUT_WR);
1205                 else
1206                         close(t->dest);
1207                 transfer_debug("Closed %s.", t->dest_name);
1208         }
1209 }
1210
1211 /*
1212  * Tries to read data from source into buffer. If buffer is full,
1213  * no data is read. Returns 0 on success, -1 on error.
1214  */
1215 static int udt_do_read(struct unidirectional_transfer *t)
1216 {
1217         ssize_t bytes;
1218
1219         if (t->bufuse == BUFFERSIZE)
1220                 return 0;       /* No space for more. */
1221
1222         transfer_debug("%s is readable", t->src_name);
1223         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1224         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1225                 errno != EINTR) {
1226                 error_errno("read(%s) failed", t->src_name);
1227                 return -1;
1228         } else if (bytes == 0) {
1229                 transfer_debug("%s EOF (with %i bytes in buffer)",
1230                         t->src_name, (int)t->bufuse);
1231                 t->state = SSTATE_FLUSHING;
1232         } else if (bytes > 0) {
1233                 t->bufuse += bytes;
1234                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1235                         (int)bytes, t->src_name, (int)t->bufuse);
1236         }
1237         return 0;
1238 }
1239
1240 /* Tries to write data from buffer into destination. If buffer is empty,
1241  * no data is written. Returns 0 on success, -1 on error.
1242  */
1243 static int udt_do_write(struct unidirectional_transfer *t)
1244 {
1245         ssize_t bytes;
1246
1247         if (t->bufuse == 0)
1248                 return 0;       /* Nothing to write. */
1249
1250         transfer_debug("%s is writable", t->dest_name);
1251         bytes = xwrite(t->dest, t->buf, t->bufuse);
1252         if (bytes < 0 && errno != EWOULDBLOCK) {
1253                 error_errno("write(%s) failed", t->dest_name);
1254                 return -1;
1255         } else if (bytes > 0) {
1256                 t->bufuse -= bytes;
1257                 if (t->bufuse)
1258                         memmove(t->buf, t->buf + bytes, t->bufuse);
1259                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1260                         (int)bytes, t->dest_name, (int)t->bufuse);
1261         }
1262         return 0;
1263 }
1264
1265
1266 /* State of bidirectional transfer loop. */
1267 struct bidirectional_transfer_state {
1268         /* Direction from program to git. */
1269         struct unidirectional_transfer ptg;
1270         /* Direction from git to program. */
1271         struct unidirectional_transfer gtp;
1272 };
1273
1274 static void *udt_copy_task_routine(void *udt)
1275 {
1276         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1277         while (t->state != SSTATE_FINISHED) {
1278                 if (STATE_NEEDS_READING(t->state))
1279                         if (udt_do_read(t))
1280                                 return NULL;
1281                 if (STATE_NEEDS_WRITING(t->state))
1282                         if (udt_do_write(t))
1283                                 return NULL;
1284                 if (STATE_NEEDS_CLOSING(t->state))
1285                         udt_close_if_finished(t);
1286         }
1287         return udt;     /* Just some non-NULL value. */
1288 }
1289
1290 #ifndef NO_PTHREADS
1291
1292 /*
1293  * Join thread, with appropriate errors on failure. Name is name for the
1294  * thread (for error messages). Returns 0 on success, 1 on failure.
1295  */
1296 static int tloop_join(pthread_t thread, const char *name)
1297 {
1298         int err;
1299         void *tret;
1300         err = pthread_join(thread, &tret);
1301         if (!tret) {
1302                 error("%s thread failed", name);
1303                 return 1;
1304         }
1305         if (err) {
1306                 error("%s thread failed to join: %s", name, strerror(err));
1307                 return 1;
1308         }
1309         return 0;
1310 }
1311
1312 /*
1313  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1314  * -1 on failure.
1315  */
1316 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1317 {
1318         pthread_t gtp_thread;
1319         pthread_t ptg_thread;
1320         int err;
1321         int ret = 0;
1322         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1323                 &s->gtp);
1324         if (err)
1325                 die("Can't start thread for copying data: %s", strerror(err));
1326         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1327                 &s->ptg);
1328         if (err)
1329                 die("Can't start thread for copying data: %s", strerror(err));
1330
1331         ret |= tloop_join(gtp_thread, "Git to program copy");
1332         ret |= tloop_join(ptg_thread, "Program to git copy");
1333         return ret;
1334 }
1335 #else
1336
1337 /* Close the source and target (for writing) for transfer. */
1338 static void udt_kill_transfer(struct unidirectional_transfer *t)
1339 {
1340         t->state = SSTATE_FINISHED;
1341         /*
1342          * Socket read end left open isn't a disaster if nobody
1343          * attempts to read from it (mingw compat headers do not
1344          * have SHUT_RD)...
1345          *
1346          * We can't fully close the socket since otherwise gtp
1347          * task would first close the socket it sends data to
1348          * while closing the ptg file descriptors.
1349          */
1350         if (!t->src_is_sock)
1351                 close(t->src);
1352         if (t->dest_is_sock)
1353                 shutdown(t->dest, SHUT_WR);
1354         else
1355                 close(t->dest);
1356 }
1357
1358 /*
1359  * Join process, with appropriate errors on failure. Name is name for the
1360  * process (for error messages). Returns 0 on success, 1 on failure.
1361  */
1362 static int tloop_join(pid_t pid, const char *name)
1363 {
1364         int tret;
1365         if (waitpid(pid, &tret, 0) < 0) {
1366                 error_errno("%s process failed to wait", name);
1367                 return 1;
1368         }
1369         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1370                 error("%s process failed", name);
1371                 return 1;
1372         }
1373         return 0;
1374 }
1375
1376 /*
1377  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1378  * -1 on failure.
1379  */
1380 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1381 {
1382         pid_t pid1, pid2;
1383         int ret = 0;
1384
1385         /* Fork thread #1: git to program. */
1386         pid1 = fork();
1387         if (pid1 < 0)
1388                 die_errno("Can't start thread for copying data");
1389         else if (pid1 == 0) {
1390                 udt_kill_transfer(&s->ptg);
1391                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1392         }
1393
1394         /* Fork thread #2: program to git. */
1395         pid2 = fork();
1396         if (pid2 < 0)
1397                 die_errno("Can't start thread for copying data");
1398         else if (pid2 == 0) {
1399                 udt_kill_transfer(&s->gtp);
1400                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1401         }
1402
1403         /*
1404          * Close both streams in parent as to not interfere with
1405          * end of file detection and wait for both tasks to finish.
1406          */
1407         udt_kill_transfer(&s->gtp);
1408         udt_kill_transfer(&s->ptg);
1409         ret |= tloop_join(pid1, "Git to program copy");
1410         ret |= tloop_join(pid2, "Program to git copy");
1411         return ret;
1412 }
1413 #endif
1414
1415 /*
1416  * Copies data from stdin to output and from input to stdout simultaneously.
1417  * Additionally filtering through given filter. If filter is NULL, uses
1418  * identity filter.
1419  */
1420 int bidirectional_transfer_loop(int input, int output)
1421 {
1422         struct bidirectional_transfer_state state;
1423
1424         /* Fill the state fields. */
1425         state.ptg.src = input;
1426         state.ptg.dest = 1;
1427         state.ptg.src_is_sock = (input == output);
1428         state.ptg.dest_is_sock = 0;
1429         state.ptg.state = SSTATE_TRANSFERRING;
1430         state.ptg.bufuse = 0;
1431         state.ptg.src_name = "remote input";
1432         state.ptg.dest_name = "stdout";
1433
1434         state.gtp.src = 0;
1435         state.gtp.dest = output;
1436         state.gtp.src_is_sock = 0;
1437         state.gtp.dest_is_sock = (input == output);
1438         state.gtp.state = SSTATE_TRANSFERRING;
1439         state.gtp.bufuse = 0;
1440         state.gtp.src_name = "stdin";
1441         state.gtp.dest_name = "remote output";
1442
1443         return tloop_spawnwait_tasks(&state);
1444 }