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