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