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