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