Merge branch 'maint-1.7.6' into maint-1.7.7
[git] / transport-helper.c
1 #include "cache.h"
2 #include "transport.h"
3 #include "quote.h"
4 #include "run-command.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "revision.h"
8 #include "quote.h"
9 #include "remote.h"
10 #include "string-list.h"
11 #include "thread-utils.h"
12
13 static int debug;
14
15 struct helper_data {
16         const char *name;
17         struct child_process *helper;
18         FILE *out;
19         unsigned fetch : 1,
20                 import : 1,
21                 export : 1,
22                 option : 1,
23                 push : 1,
24                 connect : 1,
25                 no_disconnect_req : 1;
26         char *export_marks;
27         char *import_marks;
28         /* These go from remote name (as in "list") to private name */
29         struct refspec *refspecs;
30         int refspec_nr;
31         /* Transport options for fetch-pack/send-pack (should one of
32          * those be invoked).
33          */
34         struct git_transport_options transport_options;
35 };
36
37 static void sendline(struct helper_data *helper, struct strbuf *buffer)
38 {
39         if (debug)
40                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
41         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
42                 != buffer->len)
43                 die_errno("Full write to remote helper failed");
44 }
45
46 static int recvline_fh(FILE *helper, struct strbuf *buffer)
47 {
48         strbuf_reset(buffer);
49         if (debug)
50                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
51         if (strbuf_getline(buffer, helper, '\n') == EOF) {
52                 if (debug)
53                         fprintf(stderr, "Debug: Remote helper quit.\n");
54                 exit(128);
55         }
56
57         if (debug)
58                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
59         return 0;
60 }
61
62 static int recvline(struct helper_data *helper, struct strbuf *buffer)
63 {
64         return recvline_fh(helper->out, buffer);
65 }
66
67 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
68 {
69         sendline(helper, buffer);
70         recvline(helper, buffer);
71 }
72
73 static void write_constant(int fd, const char *str)
74 {
75         if (debug)
76                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
77         if (write_in_full(fd, str, strlen(str)) != strlen(str))
78                 die_errno("Full write to remote helper failed");
79 }
80
81 static const char *remove_ext_force(const char *url)
82 {
83         if (url) {
84                 const char *colon = strchr(url, ':');
85                 if (colon && colon[1] == ':')
86                         return colon + 2;
87         }
88         return url;
89 }
90
91 static void do_take_over(struct transport *transport)
92 {
93         struct helper_data *data;
94         data = (struct helper_data *)transport->data;
95         transport_take_over(transport, data->helper);
96         fclose(data->out);
97         free(data);
98 }
99
100 static struct child_process *get_helper(struct transport *transport)
101 {
102         struct helper_data *data = transport->data;
103         struct strbuf buf = STRBUF_INIT;
104         struct child_process *helper;
105         const char **refspecs = NULL;
106         int refspec_nr = 0;
107         int refspec_alloc = 0;
108         int duped;
109         int code;
110         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
111         const char *helper_env[] = {
112                 git_dir_buf,
113                 NULL
114         };
115
116
117         if (data->helper)
118                 return data->helper;
119
120         helper = xcalloc(1, sizeof(*helper));
121         helper->in = -1;
122         helper->out = -1;
123         helper->err = 0;
124         helper->argv = xcalloc(4, sizeof(*helper->argv));
125         strbuf_addf(&buf, "git-remote-%s", data->name);
126         helper->argv[0] = strbuf_detach(&buf, NULL);
127         helper->argv[1] = transport->remote->name;
128         helper->argv[2] = remove_ext_force(transport->url);
129         helper->git_cmd = 0;
130         helper->silent_exec_failure = 1;
131
132         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
133         helper->env = helper_env;
134
135         code = start_command(helper);
136         if (code < 0 && errno == ENOENT)
137                 die("Unable to find remote helper for '%s'", data->name);
138         else if (code != 0)
139                 exit(code);
140
141         data->helper = helper;
142         data->no_disconnect_req = 0;
143
144         /*
145          * Open the output as FILE* so strbuf_getline() can be used.
146          * Do this with duped fd because fclose() will close the fd,
147          * and stuff like taking over will require the fd to remain.
148          */
149         duped = dup(helper->out);
150         if (duped < 0)
151                 die_errno("Can't dup helper output fd");
152         data->out = xfdopen(duped, "r");
153
154         write_constant(helper->in, "capabilities\n");
155
156         while (1) {
157                 const char *capname;
158                 int mandatory = 0;
159                 recvline(data, &buf);
160
161                 if (!*buf.buf)
162                         break;
163
164                 if (*buf.buf == '*') {
165                         capname = buf.buf + 1;
166                         mandatory = 1;
167                 } else
168                         capname = buf.buf;
169
170                 if (debug)
171                         fprintf(stderr, "Debug: Got cap %s\n", capname);
172                 if (!strcmp(capname, "fetch"))
173                         data->fetch = 1;
174                 else if (!strcmp(capname, "option"))
175                         data->option = 1;
176                 else if (!strcmp(capname, "push"))
177                         data->push = 1;
178                 else if (!strcmp(capname, "import"))
179                         data->import = 1;
180                 else if (!strcmp(capname, "export"))
181                         data->export = 1;
182                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
183                         ALLOC_GROW(refspecs,
184                                    refspec_nr + 1,
185                                    refspec_alloc);
186                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
187                 } else if (!strcmp(capname, "connect")) {
188                         data->connect = 1;
189                 } else if (!prefixcmp(capname, "export-marks ")) {
190                         struct strbuf arg = STRBUF_INIT;
191                         strbuf_addstr(&arg, "--export-marks=");
192                         strbuf_addstr(&arg, capname + strlen("export-marks "));
193                         data->export_marks = strbuf_detach(&arg, NULL);
194                 } else if (!prefixcmp(capname, "import-marks")) {
195                         struct strbuf arg = STRBUF_INIT;
196                         strbuf_addstr(&arg, "--import-marks=");
197                         strbuf_addstr(&arg, capname + strlen("import-marks "));
198                         data->import_marks = strbuf_detach(&arg, NULL);
199                 } else if (mandatory) {
200                         die("Unknown mandatory capability %s. This remote "
201                             "helper probably needs newer version of Git.\n",
202                             capname);
203                 }
204         }
205         if (refspecs) {
206                 int i;
207                 data->refspec_nr = refspec_nr;
208                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
209                 for (i = 0; i < refspec_nr; i++) {
210                         free((char *)refspecs[i]);
211                 }
212                 free(refspecs);
213         }
214         strbuf_release(&buf);
215         if (debug)
216                 fprintf(stderr, "Debug: Capabilities complete.\n");
217         return data->helper;
218 }
219
220 static int disconnect_helper(struct transport *transport)
221 {
222         struct helper_data *data = transport->data;
223         struct strbuf buf = STRBUF_INIT;
224         int res = 0;
225
226         if (data->helper) {
227                 if (debug)
228                         fprintf(stderr, "Debug: Disconnecting.\n");
229                 if (!data->no_disconnect_req) {
230                         strbuf_addf(&buf, "\n");
231                         sendline(data, &buf);
232                 }
233                 close(data->helper->in);
234                 close(data->helper->out);
235                 fclose(data->out);
236                 res = finish_command(data->helper);
237                 free((char *)data->helper->argv[0]);
238                 free(data->helper->argv);
239                 free(data->helper);
240                 data->helper = NULL;
241         }
242         return res;
243 }
244
245 static const char *unsupported_options[] = {
246         TRANS_OPT_UPLOADPACK,
247         TRANS_OPT_RECEIVEPACK,
248         TRANS_OPT_THIN,
249         TRANS_OPT_KEEP
250         };
251 static const char *boolean_options[] = {
252         TRANS_OPT_THIN,
253         TRANS_OPT_KEEP,
254         TRANS_OPT_FOLLOWTAGS
255         };
256
257 static int set_helper_option(struct transport *transport,
258                           const char *name, const char *value)
259 {
260         struct helper_data *data = transport->data;
261         struct strbuf buf = STRBUF_INIT;
262         int i, ret, is_bool = 0;
263
264         get_helper(transport);
265
266         if (!data->option)
267                 return 1;
268
269         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
270                 if (!strcmp(name, unsupported_options[i]))
271                         return 1;
272         }
273
274         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
275                 if (!strcmp(name, boolean_options[i])) {
276                         is_bool = 1;
277                         break;
278                 }
279         }
280
281         strbuf_addf(&buf, "option %s ", name);
282         if (is_bool)
283                 strbuf_addstr(&buf, value ? "true" : "false");
284         else
285                 quote_c_style(value, &buf, NULL, 0);
286         strbuf_addch(&buf, '\n');
287
288         xchgline(data, &buf);
289
290         if (!strcmp(buf.buf, "ok"))
291                 ret = 0;
292         else if (!prefixcmp(buf.buf, "error")) {
293                 ret = -1;
294         } else if (!strcmp(buf.buf, "unsupported"))
295                 ret = 1;
296         else {
297                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
298                 ret = 1;
299         }
300         strbuf_release(&buf);
301         return ret;
302 }
303
304 static void standard_options(struct transport *t)
305 {
306         char buf[16];
307         int n;
308         int v = t->verbose;
309
310         set_helper_option(t, "progress", t->progress ? "true" : "false");
311
312         n = snprintf(buf, sizeof(buf), "%d", v + 1);
313         if (n >= sizeof(buf))
314                 die("impossibly large verbosity value");
315         set_helper_option(t, "verbosity", buf);
316 }
317
318 static int release_helper(struct transport *transport)
319 {
320         int res = 0;
321         struct helper_data *data = transport->data;
322         free_refspec(data->refspec_nr, data->refspecs);
323         data->refspecs = NULL;
324         res = disconnect_helper(transport);
325         free(transport->data);
326         return res;
327 }
328
329 static int fetch_with_fetch(struct transport *transport,
330                             int nr_heads, struct ref **to_fetch)
331 {
332         struct helper_data *data = transport->data;
333         int i;
334         struct strbuf buf = STRBUF_INIT;
335
336         standard_options(transport);
337
338         for (i = 0; i < nr_heads; i++) {
339                 const struct ref *posn = to_fetch[i];
340                 if (posn->status & REF_STATUS_UPTODATE)
341                         continue;
342
343                 strbuf_addf(&buf, "fetch %s %s\n",
344                             sha1_to_hex(posn->old_sha1), posn->name);
345         }
346
347         strbuf_addch(&buf, '\n');
348         sendline(data, &buf);
349
350         while (1) {
351                 recvline(data, &buf);
352
353                 if (!prefixcmp(buf.buf, "lock ")) {
354                         const char *name = buf.buf + 5;
355                         if (transport->pack_lockfile)
356                                 warning("%s also locked %s", data->name, name);
357                         else
358                                 transport->pack_lockfile = xstrdup(name);
359                 }
360                 else if (!buf.len)
361                         break;
362                 else
363                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
364         }
365         strbuf_release(&buf);
366         return 0;
367 }
368
369 static int get_importer(struct transport *transport, struct child_process *fastimport)
370 {
371         struct child_process *helper = get_helper(transport);
372         memset(fastimport, 0, sizeof(*fastimport));
373         fastimport->in = helper->out;
374         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
375         fastimport->argv[0] = "fast-import";
376         fastimport->argv[1] = "--quiet";
377
378         fastimport->git_cmd = 1;
379         return start_command(fastimport);
380 }
381
382 static int get_exporter(struct transport *transport,
383                         struct child_process *fastexport,
384                         struct string_list *revlist_args)
385 {
386         struct helper_data *data = transport->data;
387         struct child_process *helper = get_helper(transport);
388         int argc = 0, i;
389         memset(fastexport, 0, sizeof(*fastexport));
390
391         /* we need to duplicate helper->in because we want to use it after
392          * fastexport is done with it. */
393         fastexport->out = dup(helper->in);
394         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
395         fastexport->argv[argc++] = "fast-export";
396         fastexport->argv[argc++] = "--use-done-feature";
397         if (data->export_marks)
398                 fastexport->argv[argc++] = data->export_marks;
399         if (data->import_marks)
400                 fastexport->argv[argc++] = data->import_marks;
401
402         for (i = 0; i < revlist_args->nr; i++)
403                 fastexport->argv[argc++] = revlist_args->items[i].string;
404
405         fastexport->git_cmd = 1;
406         return start_command(fastexport);
407 }
408
409 static int fetch_with_import(struct transport *transport,
410                              int nr_heads, struct ref **to_fetch)
411 {
412         struct child_process fastimport;
413         struct helper_data *data = transport->data;
414         int i;
415         struct ref *posn;
416         struct strbuf buf = STRBUF_INIT;
417
418         get_helper(transport);
419
420         if (get_importer(transport, &fastimport))
421                 die("Couldn't run fast-import");
422
423         for (i = 0; i < nr_heads; i++) {
424                 posn = to_fetch[i];
425                 if (posn->status & REF_STATUS_UPTODATE)
426                         continue;
427
428                 strbuf_addf(&buf, "import %s\n", posn->name);
429                 sendline(data, &buf);
430                 strbuf_reset(&buf);
431         }
432
433         write_constant(data->helper->in, "\n");
434
435         if (finish_command(&fastimport))
436                 die("Error while running fast-import");
437         free(fastimport.argv);
438         fastimport.argv = NULL;
439
440         for (i = 0; i < nr_heads; i++) {
441                 char *private;
442                 posn = to_fetch[i];
443                 if (posn->status & REF_STATUS_UPTODATE)
444                         continue;
445                 if (data->refspecs)
446                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
447                 else
448                         private = xstrdup(posn->name);
449                 read_ref(private, posn->old_sha1);
450                 free(private);
451         }
452         strbuf_release(&buf);
453         return 0;
454 }
455
456 static int process_connect_service(struct transport *transport,
457                                    const char *name, const char *exec)
458 {
459         struct helper_data *data = transport->data;
460         struct strbuf cmdbuf = STRBUF_INIT;
461         struct child_process *helper;
462         int r, duped, ret = 0;
463         FILE *input;
464
465         helper = get_helper(transport);
466
467         /*
468          * Yes, dup the pipe another time, as we need unbuffered version
469          * of input pipe as FILE*. fclose() closes the underlying fd and
470          * stream buffering only can be changed before first I/O operation
471          * on it.
472          */
473         duped = dup(helper->out);
474         if (duped < 0)
475                 die_errno("Can't dup helper output fd");
476         input = xfdopen(duped, "r");
477         setvbuf(input, NULL, _IONBF, 0);
478
479         /*
480          * Handle --upload-pack and friends. This is fire and forget...
481          * just warn if it fails.
482          */
483         if (strcmp(name, exec)) {
484                 r = set_helper_option(transport, "servpath", exec);
485                 if (r > 0)
486                         warning("Setting remote service path not supported by protocol.");
487                 else if (r < 0)
488                         warning("Invalid remote service path.");
489         }
490
491         if (data->connect)
492                 strbuf_addf(&cmdbuf, "connect %s\n", name);
493         else
494                 goto exit;
495
496         sendline(data, &cmdbuf);
497         recvline_fh(input, &cmdbuf);
498         if (!strcmp(cmdbuf.buf, "")) {
499                 data->no_disconnect_req = 1;
500                 if (debug)
501                         fprintf(stderr, "Debug: Smart transport connection "
502                                 "ready.\n");
503                 ret = 1;
504         } else if (!strcmp(cmdbuf.buf, "fallback")) {
505                 if (debug)
506                         fprintf(stderr, "Debug: Falling back to dumb "
507                                 "transport.\n");
508         } else
509                 die("Unknown response to connect: %s",
510                         cmdbuf.buf);
511
512 exit:
513         fclose(input);
514         return ret;
515 }
516
517 static int process_connect(struct transport *transport,
518                                      int for_push)
519 {
520         struct helper_data *data = transport->data;
521         const char *name;
522         const char *exec;
523
524         name = for_push ? "git-receive-pack" : "git-upload-pack";
525         if (for_push)
526                 exec = data->transport_options.receivepack;
527         else
528                 exec = data->transport_options.uploadpack;
529
530         return process_connect_service(transport, name, exec);
531 }
532
533 static int connect_helper(struct transport *transport, const char *name,
534                    const char *exec, int fd[2])
535 {
536         struct helper_data *data = transport->data;
537
538         /* Get_helper so connect is inited. */
539         get_helper(transport);
540         if (!data->connect)
541                 die("Operation not supported by protocol.");
542
543         if (!process_connect_service(transport, name, exec))
544                 die("Can't connect to subservice %s.", name);
545
546         fd[0] = data->helper->out;
547         fd[1] = data->helper->in;
548         return 0;
549 }
550
551 static int fetch(struct transport *transport,
552                  int nr_heads, struct ref **to_fetch)
553 {
554         struct helper_data *data = transport->data;
555         int i, count;
556
557         if (process_connect(transport, 0)) {
558                 do_take_over(transport);
559                 return transport->fetch(transport, nr_heads, to_fetch);
560         }
561
562         count = 0;
563         for (i = 0; i < nr_heads; i++)
564                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
565                         count++;
566
567         if (!count)
568                 return 0;
569
570         if (data->fetch)
571                 return fetch_with_fetch(transport, nr_heads, to_fetch);
572
573         if (data->import)
574                 return fetch_with_import(transport, nr_heads, to_fetch);
575
576         return -1;
577 }
578
579 static void push_update_ref_status(struct strbuf *buf,
580                                    struct ref **ref,
581                                    struct ref *remote_refs)
582 {
583         char *refname, *msg;
584         int status;
585
586         if (!prefixcmp(buf->buf, "ok ")) {
587                 status = REF_STATUS_OK;
588                 refname = buf->buf + 3;
589         } else if (!prefixcmp(buf->buf, "error ")) {
590                 status = REF_STATUS_REMOTE_REJECT;
591                 refname = buf->buf + 6;
592         } else
593                 die("expected ok/error, helper said '%s'\n", buf->buf);
594
595         msg = strchr(refname, ' ');
596         if (msg) {
597                 struct strbuf msg_buf = STRBUF_INIT;
598                 const char *end;
599
600                 *msg++ = '\0';
601                 if (!unquote_c_style(&msg_buf, msg, &end))
602                         msg = strbuf_detach(&msg_buf, NULL);
603                 else
604                         msg = xstrdup(msg);
605                 strbuf_release(&msg_buf);
606
607                 if (!strcmp(msg, "no match")) {
608                         status = REF_STATUS_NONE;
609                         free(msg);
610                         msg = NULL;
611                 }
612                 else if (!strcmp(msg, "up to date")) {
613                         status = REF_STATUS_UPTODATE;
614                         free(msg);
615                         msg = NULL;
616                 }
617                 else if (!strcmp(msg, "non-fast forward")) {
618                         status = REF_STATUS_REJECT_NONFASTFORWARD;
619                         free(msg);
620                         msg = NULL;
621                 }
622         }
623
624         if (*ref)
625                 *ref = find_ref_by_name(*ref, refname);
626         if (!*ref)
627                 *ref = find_ref_by_name(remote_refs, refname);
628         if (!*ref) {
629                 warning("helper reported unexpected status of %s", refname);
630                 return;
631         }
632
633         if ((*ref)->status != REF_STATUS_NONE) {
634                 /*
635                  * Earlier, the ref was marked not to be pushed, so ignore the ref
636                  * status reported by the remote helper if the latter is 'no match'.
637                  */
638                 if (status == REF_STATUS_NONE)
639                         return;
640         }
641
642         (*ref)->status = status;
643         (*ref)->remote_status = msg;
644 }
645
646 static void push_update_refs_status(struct helper_data *data,
647                                     struct ref *remote_refs)
648 {
649         struct strbuf buf = STRBUF_INIT;
650         struct ref *ref = remote_refs;
651         for (;;) {
652                 recvline(data, &buf);
653                 if (!buf.len)
654                         break;
655
656                 push_update_ref_status(&buf, &ref, remote_refs);
657         }
658         strbuf_release(&buf);
659 }
660
661 static int push_refs_with_push(struct transport *transport,
662                 struct ref *remote_refs, int flags)
663 {
664         int force_all = flags & TRANSPORT_PUSH_FORCE;
665         int mirror = flags & TRANSPORT_PUSH_MIRROR;
666         struct helper_data *data = transport->data;
667         struct strbuf buf = STRBUF_INIT;
668         struct ref *ref;
669
670         get_helper(transport);
671         if (!data->push)
672                 return 1;
673
674         for (ref = remote_refs; ref; ref = ref->next) {
675                 if (!ref->peer_ref && !mirror)
676                         continue;
677
678                 /* Check for statuses set by set_ref_status_for_push() */
679                 switch (ref->status) {
680                 case REF_STATUS_REJECT_NONFASTFORWARD:
681                 case REF_STATUS_UPTODATE:
682                         continue;
683                 default:
684                         ; /* do nothing */
685                 }
686
687                 if (force_all)
688                         ref->force = 1;
689
690                 strbuf_addstr(&buf, "push ");
691                 if (!ref->deletion) {
692                         if (ref->force)
693                                 strbuf_addch(&buf, '+');
694                         if (ref->peer_ref)
695                                 strbuf_addstr(&buf, ref->peer_ref->name);
696                         else
697                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
698                 }
699                 strbuf_addch(&buf, ':');
700                 strbuf_addstr(&buf, ref->name);
701                 strbuf_addch(&buf, '\n');
702         }
703         if (buf.len == 0)
704                 return 0;
705
706         standard_options(transport);
707
708         if (flags & TRANSPORT_PUSH_DRY_RUN) {
709                 if (set_helper_option(transport, "dry-run", "true") != 0)
710                         die("helper %s does not support dry-run", data->name);
711         }
712
713         strbuf_addch(&buf, '\n');
714         sendline(data, &buf);
715         strbuf_release(&buf);
716
717         push_update_refs_status(data, remote_refs);
718         return 0;
719 }
720
721 static int push_refs_with_export(struct transport *transport,
722                 struct ref *remote_refs, int flags)
723 {
724         struct ref *ref;
725         struct child_process *helper, exporter;
726         struct helper_data *data = transport->data;
727         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
728         struct strbuf buf = STRBUF_INIT;
729
730         helper = get_helper(transport);
731
732         write_constant(helper->in, "export\n");
733
734         strbuf_reset(&buf);
735
736         for (ref = remote_refs; ref; ref = ref->next) {
737                 char *private;
738                 unsigned char sha1[20];
739
740                 if (!data->refspecs)
741                         continue;
742                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
743                 if (private && !get_sha1(private, sha1)) {
744                         strbuf_addf(&buf, "^%s", private);
745                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
746                 }
747                 free(private);
748
749                 if (ref->deletion) {
750                         die("remote-helpers do not support ref deletion");
751                 }
752
753                 if (ref->peer_ref)
754                         string_list_append(&revlist_args, ref->peer_ref->name);
755
756         }
757
758         if (get_exporter(transport, &exporter, &revlist_args))
759                 die("Couldn't run fast-export");
760
761         if (finish_command(&exporter))
762                 die("Error while running fast-export");
763         push_update_refs_status(data, remote_refs);
764         return 0;
765 }
766
767 static int push_refs(struct transport *transport,
768                 struct ref *remote_refs, int flags)
769 {
770         struct helper_data *data = transport->data;
771
772         if (process_connect(transport, 1)) {
773                 do_take_over(transport);
774                 return transport->push_refs(transport, remote_refs, flags);
775         }
776
777         if (!remote_refs) {
778                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
779                         "Perhaps you should specify a branch such as 'master'.\n");
780                 return 0;
781         }
782
783         if (data->push)
784                 return push_refs_with_push(transport, remote_refs, flags);
785
786         if (data->export)
787                 return push_refs_with_export(transport, remote_refs, flags);
788
789         return -1;
790 }
791
792
793 static int has_attribute(const char *attrs, const char *attr) {
794         int len;
795         if (!attrs)
796                 return 0;
797
798         len = strlen(attr);
799         for (;;) {
800                 const char *space = strchrnul(attrs, ' ');
801                 if (len == space - attrs && !strncmp(attrs, attr, len))
802                         return 1;
803                 if (!*space)
804                         return 0;
805                 attrs = space + 1;
806         }
807 }
808
809 static struct ref *get_refs_list(struct transport *transport, int for_push)
810 {
811         struct helper_data *data = transport->data;
812         struct child_process *helper;
813         struct ref *ret = NULL;
814         struct ref **tail = &ret;
815         struct ref *posn;
816         struct strbuf buf = STRBUF_INIT;
817
818         helper = get_helper(transport);
819
820         if (process_connect(transport, for_push)) {
821                 do_take_over(transport);
822                 return transport->get_refs_list(transport, for_push);
823         }
824
825         if (data->push && for_push)
826                 write_str_in_full(helper->in, "list for-push\n");
827         else
828                 write_str_in_full(helper->in, "list\n");
829
830         while (1) {
831                 char *eov, *eon;
832                 recvline(data, &buf);
833
834                 if (!*buf.buf)
835                         break;
836
837                 eov = strchr(buf.buf, ' ');
838                 if (!eov)
839                         die("Malformed response in ref list: %s", buf.buf);
840                 eon = strchr(eov + 1, ' ');
841                 *eov = '\0';
842                 if (eon)
843                         *eon = '\0';
844                 *tail = alloc_ref(eov + 1);
845                 if (buf.buf[0] == '@')
846                         (*tail)->symref = xstrdup(buf.buf + 1);
847                 else if (buf.buf[0] != '?')
848                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
849                 if (eon) {
850                         if (has_attribute(eon + 1, "unchanged")) {
851                                 (*tail)->status |= REF_STATUS_UPTODATE;
852                                 read_ref((*tail)->name, (*tail)->old_sha1);
853                         }
854                 }
855                 tail = &((*tail)->next);
856         }
857         if (debug)
858                 fprintf(stderr, "Debug: Read ref listing.\n");
859         strbuf_release(&buf);
860
861         for (posn = ret; posn; posn = posn->next)
862                 resolve_remote_symref(posn, ret);
863
864         return ret;
865 }
866
867 int transport_helper_init(struct transport *transport, const char *name)
868 {
869         struct helper_data *data = xcalloc(sizeof(*data), 1);
870         data->name = name;
871
872         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
873                 debug = 1;
874
875         transport->data = data;
876         transport->set_option = set_helper_option;
877         transport->get_refs_list = get_refs_list;
878         transport->fetch = fetch;
879         transport->push_refs = push_refs;
880         transport->disconnect = release_helper;
881         transport->connect = connect_helper;
882         transport->smart_options = &(data->transport_options);
883         return 0;
884 }
885
886 /*
887  * Linux pipes can buffer 65536 bytes at once (and most platforms can
888  * buffer less), so attempt reads and writes with up to that size.
889  */
890 #define BUFFERSIZE 65536
891 /* This should be enough to hold debugging message. */
892 #define PBUFFERSIZE 8192
893
894 /* Print bidirectional transfer loop debug message. */
895 static void transfer_debug(const char *fmt, ...)
896 {
897         va_list args;
898         char msgbuf[PBUFFERSIZE];
899         static int debug_enabled = -1;
900
901         if (debug_enabled < 0)
902                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
903         if (!debug_enabled)
904                 return;
905
906         va_start(args, fmt);
907         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
908         va_end(args);
909         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
910 }
911
912 /* Stream state: More data may be coming in this direction. */
913 #define SSTATE_TRANSFERING 0
914 /*
915  * Stream state: No more data coming in this direction, flushing rest of
916  * data.
917  */
918 #define SSTATE_FLUSHING 1
919 /* Stream state: Transfer in this direction finished. */
920 #define SSTATE_FINISHED 2
921
922 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
923 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
924 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
925
926 /* Unidirectional transfer. */
927 struct unidirectional_transfer {
928         /* Source */
929         int src;
930         /* Destination */
931         int dest;
932         /* Is source socket? */
933         int src_is_sock;
934         /* Is destination socket? */
935         int dest_is_sock;
936         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
937         int state;
938         /* Buffer. */
939         char buf[BUFFERSIZE];
940         /* Buffer used. */
941         size_t bufuse;
942         /* Name of source. */
943         const char *src_name;
944         /* Name of destination. */
945         const char *dest_name;
946 };
947
948 /* Closes the target (for writing) if transfer has finished. */
949 static void udt_close_if_finished(struct unidirectional_transfer *t)
950 {
951         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
952                 t->state = SSTATE_FINISHED;
953                 if (t->dest_is_sock)
954                         shutdown(t->dest, SHUT_WR);
955                 else
956                         close(t->dest);
957                 transfer_debug("Closed %s.", t->dest_name);
958         }
959 }
960
961 /*
962  * Tries to read read data from source into buffer. If buffer is full,
963  * no data is read. Returns 0 on success, -1 on error.
964  */
965 static int udt_do_read(struct unidirectional_transfer *t)
966 {
967         ssize_t bytes;
968
969         if (t->bufuse == BUFFERSIZE)
970                 return 0;       /* No space for more. */
971
972         transfer_debug("%s is readable", t->src_name);
973         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
974         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
975                 errno != EINTR) {
976                 error("read(%s) failed: %s", t->src_name, strerror(errno));
977                 return -1;
978         } else if (bytes == 0) {
979                 transfer_debug("%s EOF (with %i bytes in buffer)",
980                         t->src_name, t->bufuse);
981                 t->state = SSTATE_FLUSHING;
982         } else if (bytes > 0) {
983                 t->bufuse += bytes;
984                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
985                         (int)bytes, t->src_name, (int)t->bufuse);
986         }
987         return 0;
988 }
989
990 /* Tries to write data from buffer into destination. If buffer is empty,
991  * no data is written. Returns 0 on success, -1 on error.
992  */
993 static int udt_do_write(struct unidirectional_transfer *t)
994 {
995         ssize_t bytes;
996
997         if (t->bufuse == 0)
998                 return 0;       /* Nothing to write. */
999
1000         transfer_debug("%s is writable", t->dest_name);
1001         bytes = write(t->dest, t->buf, t->bufuse);
1002         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1003                 errno != EINTR) {
1004                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1005                 return -1;
1006         } else if (bytes > 0) {
1007                 t->bufuse -= bytes;
1008                 if (t->bufuse)
1009                         memmove(t->buf, t->buf + bytes, t->bufuse);
1010                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1011                         (int)bytes, t->dest_name, (int)t->bufuse);
1012         }
1013         return 0;
1014 }
1015
1016
1017 /* State of bidirectional transfer loop. */
1018 struct bidirectional_transfer_state {
1019         /* Direction from program to git. */
1020         struct unidirectional_transfer ptg;
1021         /* Direction from git to program. */
1022         struct unidirectional_transfer gtp;
1023 };
1024
1025 static void *udt_copy_task_routine(void *udt)
1026 {
1027         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1028         while (t->state != SSTATE_FINISHED) {
1029                 if (STATE_NEEDS_READING(t->state))
1030                         if (udt_do_read(t))
1031                                 return NULL;
1032                 if (STATE_NEEDS_WRITING(t->state))
1033                         if (udt_do_write(t))
1034                                 return NULL;
1035                 if (STATE_NEEDS_CLOSING(t->state))
1036                         udt_close_if_finished(t);
1037         }
1038         return udt;     /* Just some non-NULL value. */
1039 }
1040
1041 #ifndef NO_PTHREADS
1042
1043 /*
1044  * Join thread, with apporiate errors on failure. Name is name for the
1045  * thread (for error messages). Returns 0 on success, 1 on failure.
1046  */
1047 static int tloop_join(pthread_t thread, const char *name)
1048 {
1049         int err;
1050         void *tret;
1051         err = pthread_join(thread, &tret);
1052         if (!tret) {
1053                 error("%s thread failed", name);
1054                 return 1;
1055         }
1056         if (err) {
1057                 error("%s thread failed to join: %s", name, strerror(err));
1058                 return 1;
1059         }
1060         return 0;
1061 }
1062
1063 /*
1064  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1065  * -1 on failure.
1066  */
1067 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1068 {
1069         pthread_t gtp_thread;
1070         pthread_t ptg_thread;
1071         int err;
1072         int ret = 0;
1073         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1074                 &s->gtp);
1075         if (err)
1076                 die("Can't start thread for copying data: %s", strerror(err));
1077         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1078                 &s->ptg);
1079         if (err)
1080                 die("Can't start thread for copying data: %s", strerror(err));
1081
1082         ret |= tloop_join(gtp_thread, "Git to program copy");
1083         ret |= tloop_join(ptg_thread, "Program to git copy");
1084         return ret;
1085 }
1086 #else
1087
1088 /* Close the source and target (for writing) for transfer. */
1089 static void udt_kill_transfer(struct unidirectional_transfer *t)
1090 {
1091         t->state = SSTATE_FINISHED;
1092         /*
1093          * Socket read end left open isn't a disaster if nobody
1094          * attempts to read from it (mingw compat headers do not
1095          * have SHUT_RD)...
1096          *
1097          * We can't fully close the socket since otherwise gtp
1098          * task would first close the socket it sends data to
1099          * while closing the ptg file descriptors.
1100          */
1101         if (!t->src_is_sock)
1102                 close(t->src);
1103         if (t->dest_is_sock)
1104                 shutdown(t->dest, SHUT_WR);
1105         else
1106                 close(t->dest);
1107 }
1108
1109 /*
1110  * Join process, with apporiate errors on failure. Name is name for the
1111  * process (for error messages). Returns 0 on success, 1 on failure.
1112  */
1113 static int tloop_join(pid_t pid, const char *name)
1114 {
1115         int tret;
1116         if (waitpid(pid, &tret, 0) < 0) {
1117                 error("%s process failed to wait: %s", name, strerror(errno));
1118                 return 1;
1119         }
1120         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1121                 error("%s process failed", name);
1122                 return 1;
1123         }
1124         return 0;
1125 }
1126
1127 /*
1128  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1129  * -1 on failure.
1130  */
1131 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1132 {
1133         pid_t pid1, pid2;
1134         int ret = 0;
1135
1136         /* Fork thread #1: git to program. */
1137         pid1 = fork();
1138         if (pid1 < 0)
1139                 die_errno("Can't start thread for copying data");
1140         else if (pid1 == 0) {
1141                 udt_kill_transfer(&s->ptg);
1142                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1143         }
1144
1145         /* Fork thread #2: program to git. */
1146         pid2 = fork();
1147         if (pid2 < 0)
1148                 die_errno("Can't start thread for copying data");
1149         else if (pid2 == 0) {
1150                 udt_kill_transfer(&s->gtp);
1151                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1152         }
1153
1154         /*
1155          * Close both streams in parent as to not interfere with
1156          * end of file detection and wait for both tasks to finish.
1157          */
1158         udt_kill_transfer(&s->gtp);
1159         udt_kill_transfer(&s->ptg);
1160         ret |= tloop_join(pid1, "Git to program copy");
1161         ret |= tloop_join(pid2, "Program to git copy");
1162         return ret;
1163 }
1164 #endif
1165
1166 /*
1167  * Copies data from stdin to output and from input to stdout simultaneously.
1168  * Additionally filtering through given filter. If filter is NULL, uses
1169  * identity filter.
1170  */
1171 int bidirectional_transfer_loop(int input, int output)
1172 {
1173         struct bidirectional_transfer_state state;
1174
1175         /* Fill the state fields. */
1176         state.ptg.src = input;
1177         state.ptg.dest = 1;
1178         state.ptg.src_is_sock = (input == output);
1179         state.ptg.dest_is_sock = 0;
1180         state.ptg.state = SSTATE_TRANSFERING;
1181         state.ptg.bufuse = 0;
1182         state.ptg.src_name = "remote input";
1183         state.ptg.dest_name = "stdout";
1184
1185         state.gtp.src = 0;
1186         state.gtp.dest = output;
1187         state.gtp.src_is_sock = 0;
1188         state.gtp.dest_is_sock = (input == output);
1189         state.gtp.state = SSTATE_TRANSFERING;
1190         state.gtp.bufuse = 0;
1191         state.gtp.src_name = "stdin";
1192         state.gtp.dest_name = "remote output";
1193
1194         return tloop_spawnwait_tasks(&state);
1195 }