git.oblomov.eu Git - git/blob - transport-helper.c

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "remote.h"
   9 #include "string-list.h"
  10 #include "thread-utils.h"
  11 #include "sigchain.h"
  12 #include "argv-array.h"
  13 #include "refs.h"
  14 #include "refspec.h"
  15 #include "transport-internal.h"
  16 #include "protocol.h"
  17
  18 static int debug;
  19
  20 struct helper_data {
  21         const char *name;
  22         struct child_process *helper;
  23         FILE *out;
  24         unsigned fetch : 1,
  25                 import : 1,
  26                 bidi_import : 1,
  27                 export : 1,
  28                 option : 1,
  29                 push : 1,
  30                 connect : 1,
  31                 stateless_connect : 1,
  32                 signed_tags : 1,
  33                 check_connectivity : 1,
  34                 no_disconnect_req : 1,
  35                 no_private_update : 1;
  36         char *export_marks;
  37         char *import_marks;
  38         /* These go from remote name (as in "list") to private name */
  39         struct refspec rs;
  40         /* Transport options for fetch-pack/send-pack (should one of
  41          * those be invoked).
  42          */
  43         struct git_transport_options transport_options;
  44 };
  45
  46 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  47 {
  48         if (debug)
  49                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  50         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
  51                 die_errno(_("full write to remote helper failed"));
  52 }
  53
  54 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  55 {
  56         strbuf_reset(buffer);
  57         if (debug)
  58                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  59         if (strbuf_getline(buffer, helper) == EOF) {
  60                 if (debug)
  61                         fprintf(stderr, "Debug: Remote helper quit.\n");
  62                 return 1;
  63         }
  64
  65         if (debug)
  66                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  67         return 0;
  68 }
  69
  70 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  71 {
  72         return recvline_fh(helper->out, buffer);
  73 }
  74
  75 static void write_constant(int fd, const char *str)
  76 {
  77         if (debug)
  78                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  79         if (write_in_full(fd, str, strlen(str)) < 0)
  80                 die_errno(_("full write to remote helper failed"));
  81 }
  82
  83 static const char *remove_ext_force(const char *url)
  84 {
  85         if (url) {
  86                 const char *colon = strchr(url, ':');
  87                 if (colon && colon[1] == ':')
  88                         return colon + 2;
  89         }
  90         return url;
  91 }
  92
  93 static void do_take_over(struct transport *transport)
  94 {
  95         struct helper_data *data;
  96         data = (struct helper_data *)transport->data;
  97         transport_take_over(transport, data->helper);
  98         fclose(data->out);
  99         free(data);
 100 }
 101
 102 static void standard_options(struct transport *t);
 103
 104 static struct child_process *get_helper(struct transport *transport)
 105 {
 106         struct helper_data *data = transport->data;
 107         struct strbuf buf = STRBUF_INIT;
 108         struct child_process *helper;
 109         int duped;
 110         int code;
 111
 112         if (data->helper)
 113                 return data->helper;
 114
 115         helper = xmalloc(sizeof(*helper));
 116         child_process_init(helper);
 117         helper->in = -1;
 118         helper->out = -1;
 119         helper->err = 0;
 120         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 121         argv_array_push(&helper->args, transport->remote->name);
 122         argv_array_push(&helper->args, remove_ext_force(transport->url));
 123         helper->git_cmd = 0;
 124         helper->silent_exec_failure = 1;
 125
 126         if (have_git_dir())
 127                 argv_array_pushf(&helper->env_array, "%s=%s",
 128                                  GIT_DIR_ENVIRONMENT, get_git_dir());
 129
 130         helper->trace2_child_class = helper->args.argv[0]; /* "remote-<name>" */
 131
 132         code = start_command(helper);
 133         if (code < 0 && errno == ENOENT)
 134                 die(_("unable to find remote helper for '%s'"), data->name);
 135         else if (code != 0)
 136                 exit(code);
 137
 138         data->helper = helper;
 139         data->no_disconnect_req = 0;
 140         refspec_init(&data->rs, REFSPEC_FETCH);
 141
 142         /*
 143          * Open the output as FILE* so strbuf_getline_*() family of
 144          * functions can be used.
 145          * Do this with duped fd because fclose() will close the fd,
 146          * and stuff like taking over will require the fd to remain.
 147          */
 148         duped = dup(helper->out);
 149         if (duped < 0)
 150                 die_errno(_("can't dup helper output fd"));
 151         data->out = xfdopen(duped, "r");
 152
 153         write_constant(helper->in, "capabilities\n");
 154
 155         while (1) {
 156                 const char *capname, *arg;
 157                 int mandatory = 0;
 158                 if (recvline(data, &buf))
 159                         exit(128);
 160
 161                 if (!*buf.buf)
 162                         break;
 163
 164                 if (*buf.buf == '*') {
 165                         capname = buf.buf + 1;
 166                         mandatory = 1;
 167                 } else
 168                         capname = buf.buf;
 169
 170                 if (debug)
 171                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 172                 if (!strcmp(capname, "fetch"))
 173                         data->fetch = 1;
 174                 else if (!strcmp(capname, "option"))
 175                         data->option = 1;
 176                 else if (!strcmp(capname, "push"))
 177                         data->push = 1;
 178                 else if (!strcmp(capname, "import"))
 179                         data->import = 1;
 180                 else if (!strcmp(capname, "bidi-import"))
 181                         data->bidi_import = 1;
 182                 else if (!strcmp(capname, "export"))
 183                         data->export = 1;
 184                 else if (!strcmp(capname, "check-connectivity"))
 185                         data->check_connectivity = 1;
 186                 else if (skip_prefix(capname, "refspec ", &arg)) {
 187                         refspec_append(&data->rs, arg);
 188                 } else if (!strcmp(capname, "connect")) {
 189                         data->connect = 1;
 190                 } else if (!strcmp(capname, "stateless-connect")) {
 191                         data->stateless_connect = 1;
 192                 } else if (!strcmp(capname, "signed-tags")) {
 193                         data->signed_tags = 1;
 194                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 195                         data->export_marks = xstrdup(arg);
 196                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 197                         data->import_marks = xstrdup(arg);
 198                 } else if (starts_with(capname, "no-private-update")) {
 199                         data->no_private_update = 1;
 200                 } else if (mandatory) {
 201                         die(_("unknown mandatory capability %s; this remote "
 202                               "helper probably needs newer version of Git"),
 203                             capname);
 204                 }
 205         }
 206         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
 207                 warning(_("this remote helper should implement refspec capability"));
 208         }
 209         strbuf_release(&buf);
 210         if (debug)
 211                 fprintf(stderr, "Debug: Capabilities complete.\n");
 212         standard_options(transport);
 213         return data->helper;
 214 }
 215
 216 static int disconnect_helper(struct transport *transport)
 217 {
 218         struct helper_data *data = transport->data;
 219         int res = 0;
 220
 221         if (data->helper) {
 222                 if (debug)
 223                         fprintf(stderr, "Debug: Disconnecting.\n");
 224                 if (!data->no_disconnect_req) {
 225                         /*
 226                          * Ignore write errors; there's nothing we can do,
 227                          * since we're about to close the pipe anyway. And the
 228                          * most likely error is EPIPE due to the helper dying
 229                          * to report an error itself.
 230                          */
 231                         sigchain_push(SIGPIPE, SIG_IGN);
 232                         xwrite(data->helper->in, "\n", 1);
 233                         sigchain_pop(SIGPIPE);
 234                 }
 235                 close(data->helper->in);
 236                 close(data->helper->out);
 237                 fclose(data->out);
 238                 res = finish_command(data->helper);
 239                 FREE_AND_NULL(data->helper);
 240         }
 241         return res;
 242 }
 243
 244 static const char *unsupported_options[] = {
 245         TRANS_OPT_UPLOADPACK,
 246         TRANS_OPT_RECEIVEPACK,
 247         TRANS_OPT_THIN,
 248         TRANS_OPT_KEEP
 249         };
 250
 251 static const char *boolean_options[] = {
 252         TRANS_OPT_THIN,
 253         TRANS_OPT_KEEP,
 254         TRANS_OPT_FOLLOWTAGS,
 255         TRANS_OPT_DEEPEN_RELATIVE
 256         };
 257
 258 static int strbuf_set_helper_option(struct helper_data *data,
 259                                     struct strbuf *buf)
 260 {
 261         int ret;
 262
 263         sendline(data, buf);
 264         if (recvline(data, buf))
 265                 exit(128);
 266
 267         if (!strcmp(buf->buf, "ok"))
 268                 ret = 0;
 269         else if (starts_with(buf->buf, "error"))
 270                 ret = -1;
 271         else if (!strcmp(buf->buf, "unsupported"))
 272                 ret = 1;
 273         else {
 274                 warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
 275                 ret = 1;
 276         }
 277         return ret;
 278 }
 279
 280 static int string_list_set_helper_option(struct helper_data *data,
 281                                          const char *name,
 282                                          struct string_list *list)
 283 {
 284         struct strbuf buf = STRBUF_INIT;
 285         int i, ret = 0;
 286
 287         for (i = 0; i < list->nr; i++) {
 288                 strbuf_addf(&buf, "option %s ", name);
 289                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 290                 strbuf_addch(&buf, '\n');
 291
 292                 if ((ret = strbuf_set_helper_option(data, &buf)))
 293                         break;
 294                 strbuf_reset(&buf);
 295         }
 296         strbuf_release(&buf);
 297         return ret;
 298 }
 299
 300 static int set_helper_option(struct transport *transport,
 301                           const char *name, const char *value)
 302 {
 303         struct helper_data *data = transport->data;
 304         struct strbuf buf = STRBUF_INIT;
 305         int i, ret, is_bool = 0;
 306
 307         get_helper(transport);
 308
 309         if (!data->option)
 310                 return 1;
 311
 312         if (!strcmp(name, "deepen-not"))
 313                 return string_list_set_helper_option(data, name,
 314                                                      (struct string_list *)value);
 315
 316         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 317                 if (!strcmp(name, unsupported_options[i]))
 318                         return 1;
 319         }
 320
 321         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 322                 if (!strcmp(name, boolean_options[i])) {
 323                         is_bool = 1;
 324                         break;
 325                 }
 326         }
 327
 328         strbuf_addf(&buf, "option %s ", name);
 329         if (is_bool)
 330                 strbuf_addstr(&buf, value ? "true" : "false");
 331         else
 332                 quote_c_style(value, &buf, NULL, 0);
 333         strbuf_addch(&buf, '\n');
 334
 335         ret = strbuf_set_helper_option(data, &buf);
 336         strbuf_release(&buf);
 337         return ret;
 338 }
 339
 340 static void standard_options(struct transport *t)
 341 {
 342         char buf[16];
 343         int v = t->verbose;
 344
 345         set_helper_option(t, "progress", t->progress ? "true" : "false");
 346
 347         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 348         set_helper_option(t, "verbosity", buf);
 349
 350         switch (t->family) {
 351         case TRANSPORT_FAMILY_ALL:
 352                 /*
 353                  * this is already the default,
 354                  * do not break old remote helpers by setting "all" here
 355                  */
 356                 break;
 357         case TRANSPORT_FAMILY_IPV4:
 358                 set_helper_option(t, "family", "ipv4");
 359                 break;
 360         case TRANSPORT_FAMILY_IPV6:
 361                 set_helper_option(t, "family", "ipv6");
 362                 break;
 363         }
 364 }
 365
 366 static int release_helper(struct transport *transport)
 367 {
 368         int res = 0;
 369         struct helper_data *data = transport->data;
 370         refspec_clear(&data->rs);
 371         res = disconnect_helper(transport);
 372         free(transport->data);
 373         return res;
 374 }
 375
 376 static int fetch_with_fetch(struct transport *transport,
 377                             int nr_heads, struct ref **to_fetch)
 378 {
 379         struct helper_data *data = transport->data;
 380         int i;
 381         struct strbuf buf = STRBUF_INIT;
 382
 383         for (i = 0; i < nr_heads; i++) {
 384                 const struct ref *posn = to_fetch[i];
 385                 if (posn->status & REF_STATUS_UPTODATE)
 386                         continue;
 387
 388                 strbuf_addf(&buf, "fetch %s %s\n",
 389                             oid_to_hex(&posn->old_oid),
 390                             posn->symref ? posn->symref : posn->name);
 391         }
 392
 393         strbuf_addch(&buf, '\n');
 394         sendline(data, &buf);
 395
 396         while (1) {
 397                 if (recvline(data, &buf))
 398                         exit(128);
 399
 400                 if (starts_with(buf.buf, "lock ")) {
 401                         const char *name = buf.buf + 5;
 402                         if (transport->pack_lockfile)
 403                                 warning(_("%s also locked %s"), data->name, name);
 404                         else
 405                                 transport->pack_lockfile = xstrdup(name);
 406                 }
 407                 else if (data->check_connectivity &&
 408                          data->transport_options.check_self_contained_and_connected &&
 409                          !strcmp(buf.buf, "connectivity-ok"))
 410                         data->transport_options.self_contained_and_connected = 1;
 411                 else if (!buf.len)
 412                         break;
 413                 else
 414                         warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
 415         }
 416         strbuf_release(&buf);
 417         return 0;
 418 }
 419
 420 static int get_importer(struct transport *transport, struct child_process *fastimport)
 421 {
 422         struct child_process *helper = get_helper(transport);
 423         struct helper_data *data = transport->data;
 424         int cat_blob_fd, code;
 425         child_process_init(fastimport);
 426         fastimport->in = xdup(helper->out);
 427         argv_array_push(&fastimport->args, "fast-import");
 428         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 429
 430         if (data->bidi_import) {
 431                 cat_blob_fd = xdup(helper->in);
 432                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 433         }
 434         fastimport->git_cmd = 1;
 435
 436         code = start_command(fastimport);
 437         return code;
 438 }
 439
 440 static int get_exporter(struct transport *transport,
 441                         struct child_process *fastexport,
 442                         struct string_list *revlist_args)
 443 {
 444         struct helper_data *data = transport->data;
 445         struct child_process *helper = get_helper(transport);
 446         int i;
 447
 448         child_process_init(fastexport);
 449
 450         /* we need to duplicate helper->in because we want to use it after
 451          * fastexport is done with it. */
 452         fastexport->out = dup(helper->in);
 453         argv_array_push(&fastexport->args, "fast-export");
 454         argv_array_push(&fastexport->args, "--use-done-feature");
 455         argv_array_push(&fastexport->args, data->signed_tags ?
 456                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 457         if (data->export_marks)
 458                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 459         if (data->import_marks)
 460                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 461
 462         for (i = 0; i < revlist_args->nr; i++)
 463                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 464
 465         fastexport->git_cmd = 1;
 466         return start_command(fastexport);
 467 }
 468
 469 static int fetch_with_import(struct transport *transport,
 470                              int nr_heads, struct ref **to_fetch)
 471 {
 472         struct child_process fastimport;
 473         struct helper_data *data = transport->data;
 474         int i;
 475         struct ref *posn;
 476         struct strbuf buf = STRBUF_INIT;
 477
 478         get_helper(transport);
 479
 480         if (get_importer(transport, &fastimport))
 481                 die(_("couldn't run fast-import"));
 482
 483         for (i = 0; i < nr_heads; i++) {
 484                 posn = to_fetch[i];
 485                 if (posn->status & REF_STATUS_UPTODATE)
 486                         continue;
 487
 488                 strbuf_addf(&buf, "import %s\n",
 489                             posn->symref ? posn->symref : posn->name);
 490                 sendline(data, &buf);
 491                 strbuf_reset(&buf);
 492         }
 493
 494         write_constant(data->helper->in, "\n");
 495         /*
 496          * remote-helpers that advertise the bidi-import capability are required to
 497          * buffer the complete batch of import commands until this newline before
 498          * sending data to fast-import.
 499          * These helpers read back data from fast-import on their stdin, which could
 500          * be mixed with import commands, otherwise.
 501          */
 502
 503         if (finish_command(&fastimport))
 504                 die(_("error while running fast-import"));
 505
 506         /*
 507          * The fast-import stream of a remote helper that advertises
 508          * the "refspec" capability writes to the refs named after the
 509          * right hand side of the first refspec matching each ref we
 510          * were fetching.
 511          *
 512          * (If no "refspec" capability was specified, for historical
 513          * reasons we default to the equivalent of *:*.)
 514          *
 515          * Store the result in to_fetch[i].old_sha1.  Callers such
 516          * as "git fetch" can use the value to write feedback to the
 517          * terminal, populate FETCH_HEAD, and determine what new value
 518          * should be written to peer_ref if the update is a
 519          * fast-forward or this is a forced update.
 520          */
 521         for (i = 0; i < nr_heads; i++) {
 522                 char *private, *name;
 523                 posn = to_fetch[i];
 524                 if (posn->status & REF_STATUS_UPTODATE)
 525                         continue;
 526                 name = posn->symref ? posn->symref : posn->name;
 527                 if (data->rs.nr)
 528                         private = apply_refspecs(&data->rs, name);
 529                 else
 530                         private = xstrdup(name);
 531                 if (private) {
 532                         if (read_ref(private, &posn->old_oid) < 0)
 533                                 die(_("could not read ref %s"), private);
 534                         free(private);
 535                 }
 536         }
 537         strbuf_release(&buf);
 538         return 0;
 539 }
 540
 541 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 542 {
 543         struct helper_data *data = transport->data;
 544         int ret = 0;
 545         int duped;
 546         FILE *input;
 547         struct child_process *helper;
 548
 549         helper = get_helper(transport);
 550
 551         /*
 552          * Yes, dup the pipe another time, as we need unbuffered version
 553          * of input pipe as FILE*. fclose() closes the underlying fd and
 554          * stream buffering only can be changed before first I/O operation
 555          * on it.
 556          */
 557         duped = dup(helper->out);
 558         if (duped < 0)
 559                 die_errno(_("can't dup helper output fd"));
 560         input = xfdopen(duped, "r");
 561         setvbuf(input, NULL, _IONBF, 0);
 562
 563         sendline(data, cmdbuf);
 564         if (recvline_fh(input, cmdbuf))
 565                 exit(128);
 566
 567         if (!strcmp(cmdbuf->buf, "")) {
 568                 data->no_disconnect_req = 1;
 569                 if (debug)
 570                         fprintf(stderr, "Debug: Smart transport connection "
 571                                 "ready.\n");
 572                 ret = 1;
 573         } else if (!strcmp(cmdbuf->buf, "fallback")) {
 574                 if (debug)
 575                         fprintf(stderr, "Debug: Falling back to dumb "
 576                                 "transport.\n");
 577         } else {
 578                 die(_("unknown response to connect: %s"),
 579                     cmdbuf->buf);
 580         }
 581
 582         fclose(input);
 583         return ret;
 584 }
 585
 586 static int process_connect_service(struct transport *transport,
 587                                    const char *name, const char *exec)
 588 {
 589         struct helper_data *data = transport->data;
 590         struct strbuf cmdbuf = STRBUF_INIT;
 591         int ret = 0;
 592
 593         /*
 594          * Handle --upload-pack and friends. This is fire and forget...
 595          * just warn if it fails.
 596          */
 597         if (strcmp(name, exec)) {
 598                 int r = set_helper_option(transport, "servpath", exec);
 599                 if (r > 0)
 600                         warning(_("setting remote service path not supported by protocol"));
 601                 else if (r < 0)
 602                         warning(_("invalid remote service path"));
 603         }
 604
 605         if (data->connect) {
 606                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 607                 ret = run_connect(transport, &cmdbuf);
 608         } else if (data->stateless_connect &&
 609                    (get_protocol_version_config() == protocol_v2) &&
 610                    !strcmp("git-upload-pack", name)) {
 611                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 612                 ret = run_connect(transport, &cmdbuf);
 613                 if (ret)
 614                         transport->stateless_rpc = 1;
 615         }
 616
 617         strbuf_release(&cmdbuf);
 618         return ret;
 619 }
 620
 621 static int process_connect(struct transport *transport,
 622                                      int for_push)
 623 {
 624         struct helper_data *data = transport->data;
 625         const char *name;
 626         const char *exec;
 627
 628         name = for_push ? "git-receive-pack" : "git-upload-pack";
 629         if (for_push)
 630                 exec = data->transport_options.receivepack;
 631         else
 632                 exec = data->transport_options.uploadpack;
 633
 634         return process_connect_service(transport, name, exec);
 635 }
 636
 637 static int connect_helper(struct transport *transport, const char *name,
 638                    const char *exec, int fd[2])
 639 {
 640         struct helper_data *data = transport->data;
 641
 642         /* Get_helper so connect is inited. */
 643         get_helper(transport);
 644         if (!data->connect)
 645                 die(_("operation not supported by protocol"));
 646
 647         if (!process_connect_service(transport, name, exec))
 648                 die(_("can't connect to subservice %s"), name);
 649
 650         fd[0] = data->helper->out;
 651         fd[1] = data->helper->in;
 652         return 0;
 653 }
 654
 655 static int fetch(struct transport *transport,
 656                  int nr_heads, struct ref **to_fetch)
 657 {
 658         struct helper_data *data = transport->data;
 659         int i, count;
 660
 661         if (process_connect(transport, 0)) {
 662                 do_take_over(transport);
 663                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
 664         }
 665
 666         count = 0;
 667         for (i = 0; i < nr_heads; i++)
 668                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 669                         count++;
 670
 671         if (!count)
 672                 return 0;
 673
 674         if (data->check_connectivity &&
 675             data->transport_options.check_self_contained_and_connected)
 676                 set_helper_option(transport, "check-connectivity", "true");
 677
 678         if (transport->cloning)
 679                 set_helper_option(transport, "cloning", "true");
 680
 681         if (data->transport_options.update_shallow)
 682                 set_helper_option(transport, "update-shallow", "true");
 683
 684         if (data->transport_options.filter_options.choice) {
 685                 const char *spec = expand_list_objects_filter_spec(
 686                         &data->transport_options.filter_options);
 687                 set_helper_option(transport, "filter", spec);
 688         }
 689
 690         if (data->transport_options.negotiation_tips)
 691                 warning("Ignoring --negotiation-tip because the protocol does not support it.");
 692
 693         if (data->fetch)
 694                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 695
 696         if (data->import)
 697                 return fetch_with_import(transport, nr_heads, to_fetch);
 698
 699         return -1;
 700 }
 701
 702 static int push_update_ref_status(struct strbuf *buf,
 703                                    struct ref **ref,
 704                                    struct ref *remote_refs)
 705 {
 706         char *refname, *msg;
 707         int status, forced = 0;
 708
 709         if (starts_with(buf->buf, "ok ")) {
 710                 status = REF_STATUS_OK;
 711                 refname = buf->buf + 3;
 712         } else if (starts_with(buf->buf, "error ")) {
 713                 status = REF_STATUS_REMOTE_REJECT;
 714                 refname = buf->buf + 6;
 715         } else
 716                 die(_("expected ok/error, helper said '%s'"), buf->buf);
 717
 718         msg = strchr(refname, ' ');
 719         if (msg) {
 720                 struct strbuf msg_buf = STRBUF_INIT;
 721                 const char *end;
 722
 723                 *msg++ = '\0';
 724                 if (!unquote_c_style(&msg_buf, msg, &end))
 725                         msg = strbuf_detach(&msg_buf, NULL);
 726                 else
 727                         msg = xstrdup(msg);
 728                 strbuf_release(&msg_buf);
 729
 730                 if (!strcmp(msg, "no match")) {
 731                         status = REF_STATUS_NONE;
 732                         FREE_AND_NULL(msg);
 733                 }
 734                 else if (!strcmp(msg, "up to date")) {
 735                         status = REF_STATUS_UPTODATE;
 736                         FREE_AND_NULL(msg);
 737                 }
 738                 else if (!strcmp(msg, "non-fast forward")) {
 739                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 740                         FREE_AND_NULL(msg);
 741                 }
 742                 else if (!strcmp(msg, "already exists")) {
 743                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 744                         FREE_AND_NULL(msg);
 745                 }
 746                 else if (!strcmp(msg, "fetch first")) {
 747                         status = REF_STATUS_REJECT_FETCH_FIRST;
 748                         FREE_AND_NULL(msg);
 749                 }
 750                 else if (!strcmp(msg, "needs force")) {
 751                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 752                         FREE_AND_NULL(msg);
 753                 }
 754                 else if (!strcmp(msg, "stale info")) {
 755                         status = REF_STATUS_REJECT_STALE;
 756                         FREE_AND_NULL(msg);
 757                 }
 758                 else if (!strcmp(msg, "forced update")) {
 759                         forced = 1;
 760                         FREE_AND_NULL(msg);
 761                 }
 762         }
 763
 764         if (*ref)
 765                 *ref = find_ref_by_name(*ref, refname);
 766         if (!*ref)
 767                 *ref = find_ref_by_name(remote_refs, refname);
 768         if (!*ref) {
 769                 warning(_("helper reported unexpected status of %s"), refname);
 770                 return 1;
 771         }
 772
 773         if ((*ref)->status != REF_STATUS_NONE) {
 774                 /*
 775                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 776                  * status reported by the remote helper if the latter is 'no match'.
 777                  */
 778                 if (status == REF_STATUS_NONE)
 779                         return 1;
 780         }
 781
 782         (*ref)->status = status;
 783         (*ref)->forced_update |= forced;
 784         (*ref)->remote_status = msg;
 785         return !(status == REF_STATUS_OK);
 786 }
 787
 788 static int push_update_refs_status(struct helper_data *data,
 789                                     struct ref *remote_refs,
 790                                     int flags)
 791 {
 792         struct strbuf buf = STRBUF_INIT;
 793         struct ref *ref = remote_refs;
 794         int ret = 0;
 795
 796         for (;;) {
 797                 char *private;
 798
 799                 if (recvline(data, &buf)) {
 800                         ret = 1;
 801                         break;
 802                 }
 803
 804                 if (!buf.len)
 805                         break;
 806
 807                 if (push_update_ref_status(&buf, &ref, remote_refs))
 808                         continue;
 809
 810                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
 811                         continue;
 812
 813                 /* propagate back the update to the remote namespace */
 814                 private = apply_refspecs(&data->rs, ref->name);
 815                 if (!private)
 816                         continue;
 817                 update_ref("update by helper", private, &ref->new_oid, NULL,
 818                            0, 0);
 819                 free(private);
 820         }
 821         strbuf_release(&buf);
 822         return ret;
 823 }
 824
 825 static void set_common_push_options(struct transport *transport,
 826                                    const char *name, int flags)
 827 {
 828         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 829                 if (set_helper_option(transport, "dry-run", "true") != 0)
 830                         die(_("helper %s does not support dry-run"), name);
 831         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 832                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 833                         die(_("helper %s does not support --signed"), name);
 834         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 835                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 836                         die(_("helper %s does not support --signed=if-asked"), name);
 837         }
 838
 839         if (flags & TRANSPORT_PUSH_OPTIONS) {
 840                 struct string_list_item *item;
 841                 for_each_string_list_item(item, transport->push_options)
 842                         if (set_helper_option(transport, "push-option", item->string) != 0)
 843                                 die(_("helper %s does not support 'push-option'"), name);
 844         }
 845 }
 846
 847 static int push_refs_with_push(struct transport *transport,
 848                                struct ref *remote_refs, int flags)
 849 {
 850         int force_all = flags & TRANSPORT_PUSH_FORCE;
 851         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 852         struct helper_data *data = transport->data;
 853         struct strbuf buf = STRBUF_INIT;
 854         struct ref *ref;
 855         struct string_list cas_options = STRING_LIST_INIT_DUP;
 856         struct string_list_item *cas_option;
 857
 858         get_helper(transport);
 859         if (!data->push)
 860                 return 1;
 861
 862         for (ref = remote_refs; ref; ref = ref->next) {
 863                 if (!ref->peer_ref && !mirror)
 864                         continue;
 865
 866                 /* Check for statuses set by set_ref_status_for_push() */
 867                 switch (ref->status) {
 868                 case REF_STATUS_REJECT_NONFASTFORWARD:
 869                 case REF_STATUS_REJECT_STALE:
 870                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 871                 case REF_STATUS_UPTODATE:
 872                         continue;
 873                 default:
 874                         ; /* do nothing */
 875                 }
 876
 877                 if (force_all)
 878                         ref->force = 1;
 879
 880                 strbuf_addstr(&buf, "push ");
 881                 if (!ref->deletion) {
 882                         if (ref->force)
 883                                 strbuf_addch(&buf, '+');
 884                         if (ref->peer_ref)
 885                                 strbuf_addstr(&buf, ref->peer_ref->name);
 886                         else
 887                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 888                 }
 889                 strbuf_addch(&buf, ':');
 890                 strbuf_addstr(&buf, ref->name);
 891                 strbuf_addch(&buf, '\n');
 892
 893                 /*
 894                  * The "--force-with-lease" options without explicit
 895                  * values to expect have already been expanded into
 896                  * the ref->old_oid_expect[] field; we can ignore
 897                  * transport->smart_options->cas altogether and instead
 898                  * can enumerate them from the refs.
 899                  */
 900                 if (ref->expect_old_sha1) {
 901                         struct strbuf cas = STRBUF_INIT;
 902                         strbuf_addf(&cas, "%s:%s",
 903                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 904                         string_list_append_nodup(&cas_options,
 905                                                  strbuf_detach(&cas, NULL));
 906                 }
 907         }
 908         if (buf.len == 0) {
 909                 string_list_clear(&cas_options, 0);
 910                 return 0;
 911         }
 912
 913         for_each_string_list_item(cas_option, &cas_options)
 914                 set_helper_option(transport, "cas", cas_option->string);
 915         set_common_push_options(transport, data->name, flags);
 916
 917         strbuf_addch(&buf, '\n');
 918         sendline(data, &buf);
 919         strbuf_release(&buf);
 920         string_list_clear(&cas_options, 0);
 921
 922         return push_update_refs_status(data, remote_refs, flags);
 923 }
 924
 925 static int push_refs_with_export(struct transport *transport,
 926                 struct ref *remote_refs, int flags)
 927 {
 928         struct ref *ref;
 929         struct child_process *helper, exporter;
 930         struct helper_data *data = transport->data;
 931         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 932         struct strbuf buf = STRBUF_INIT;
 933
 934         if (!data->rs.nr)
 935                 die(_("remote-helper doesn't support push; refspec needed"));
 936
 937         set_common_push_options(transport, data->name, flags);
 938         if (flags & TRANSPORT_PUSH_FORCE) {
 939                 if (set_helper_option(transport, "force", "true") != 0)
 940                         warning(_("helper %s does not support 'force'"), data->name);
 941         }
 942
 943         helper = get_helper(transport);
 944
 945         write_constant(helper->in, "export\n");
 946
 947         for (ref = remote_refs; ref; ref = ref->next) {
 948                 char *private;
 949                 struct object_id oid;
 950
 951                 private = apply_refspecs(&data->rs, ref->name);
 952                 if (private && !get_oid(private, &oid)) {
 953                         strbuf_addf(&buf, "^%s", private);
 954                         string_list_append_nodup(&revlist_args,
 955                                                  strbuf_detach(&buf, NULL));
 956                         oidcpy(&ref->old_oid, &oid);
 957                 }
 958                 free(private);
 959
 960                 if (ref->peer_ref) {
 961                         if (strcmp(ref->name, ref->peer_ref->name)) {
 962                                 if (!ref->deletion) {
 963                                         const char *name;
 964                                         int flag;
 965
 966                                         /* Follow symbolic refs (mainly for HEAD). */
 967                                         name = resolve_ref_unsafe(ref->peer_ref->name,
 968                                                                   RESOLVE_REF_READING,
 969                                                                   &oid, &flag);
 970                                         if (!name || !(flag & REF_ISSYMREF))
 971                                                 name = ref->peer_ref->name;
 972
 973                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 974                                 } else
 975                                         strbuf_addf(&buf, ":%s", ref->name);
 976
 977                                 string_list_append(&revlist_args, "--refspec");
 978                                 string_list_append(&revlist_args, buf.buf);
 979                                 strbuf_release(&buf);
 980                         }
 981                         if (!ref->deletion)
 982                                 string_list_append(&revlist_args, ref->peer_ref->name);
 983                 }
 984         }
 985
 986         if (get_exporter(transport, &exporter, &revlist_args))
 987                 die(_("couldn't run fast-export"));
 988
 989         string_list_clear(&revlist_args, 1);
 990
 991         if (finish_command(&exporter))
 992                 die(_("error while running fast-export"));
 993         if (push_update_refs_status(data, remote_refs, flags))
 994                 return 1;
 995
 996         if (data->export_marks) {
 997                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 998                 rename(buf.buf, data->export_marks);
 999                 strbuf_release(&buf);
1000         }
1001
1002         return 0;
1003 }
1004
1005 static int push_refs(struct transport *transport,
1006                 struct ref *remote_refs, int flags)
1007 {
1008         struct helper_data *data = transport->data;
1009
1010         if (process_connect(transport, 1)) {
1011                 do_take_over(transport);
1012                 return transport->vtable->push_refs(transport, remote_refs, flags);
1013         }
1014
1015         if (!remote_refs) {
1016                 fprintf(stderr,
1017                         _("No refs in common and none specified; doing nothing.\n"
1018                           "Perhaps you should specify a branch such as 'master'.\n"));
1019                 return 0;
1020         }
1021
1022         if (data->push)
1023                 return push_refs_with_push(transport, remote_refs, flags);
1024
1025         if (data->export)
1026                 return push_refs_with_export(transport, remote_refs, flags);
1027
1028         return -1;
1029 }
1030
1031
1032 static int has_attribute(const char *attrs, const char *attr)
1033 {
1034         int len;
1035         if (!attrs)
1036                 return 0;
1037
1038         len = strlen(attr);
1039         for (;;) {
1040                 const char *space = strchrnul(attrs, ' ');
1041                 if (len == space - attrs && !strncmp(attrs, attr, len))
1042                         return 1;
1043                 if (!*space)
1044                         return 0;
1045                 attrs = space + 1;
1046         }
1047 }
1048
1049 static struct ref *get_refs_list(struct transport *transport, int for_push,
1050                                  const struct argv_array *ref_prefixes)
1051 {
1052         struct helper_data *data = transport->data;
1053         struct child_process *helper;
1054         struct ref *ret = NULL;
1055         struct ref **tail = &ret;
1056         struct ref *posn;
1057         struct strbuf buf = STRBUF_INIT;
1058
1059         helper = get_helper(transport);
1060
1061         if (process_connect(transport, for_push)) {
1062                 do_take_over(transport);
1063                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1064         }
1065
1066         if (data->push && for_push)
1067                 write_str_in_full(helper->in, "list for-push\n");
1068         else
1069                 write_str_in_full(helper->in, "list\n");
1070
1071         while (1) {
1072                 char *eov, *eon;
1073                 if (recvline(data, &buf))
1074                         exit(128);
1075
1076                 if (!*buf.buf)
1077                         break;
1078
1079                 eov = strchr(buf.buf, ' ');
1080                 if (!eov)
1081                         die(_("malformed response in ref list: %s"), buf.buf);
1082                 eon = strchr(eov + 1, ' ');
1083                 *eov = '\0';
1084                 if (eon)
1085                         *eon = '\0';
1086                 *tail = alloc_ref(eov + 1);
1087                 if (buf.buf[0] == '@')
1088                         (*tail)->symref = xstrdup(buf.buf + 1);
1089                 else if (buf.buf[0] != '?')
1090                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1091                 if (eon) {
1092                         if (has_attribute(eon + 1, "unchanged")) {
1093                                 (*tail)->status |= REF_STATUS_UPTODATE;
1094                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1095                                         die(_("could not read ref %s"),
1096                                             (*tail)->name);
1097                         }
1098                 }
1099                 tail = &((*tail)->next);
1100         }
1101         if (debug)
1102                 fprintf(stderr, "Debug: Read ref listing.\n");
1103         strbuf_release(&buf);
1104
1105         for (posn = ret; posn; posn = posn->next)
1106                 resolve_remote_symref(posn, ret);
1107
1108         return ret;
1109 }
1110
1111 static struct transport_vtable vtable = {
1112         0,
1113         set_helper_option,
1114         get_refs_list,
1115         fetch,
1116         push_refs,
1117         connect_helper,
1118         release_helper
1119 };
1120
1121 int transport_helper_init(struct transport *transport, const char *name)
1122 {
1123         struct helper_data *data = xcalloc(1, sizeof(*data));
1124         data->name = name;
1125
1126         transport_check_allowed(name);
1127
1128         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1129                 debug = 1;
1130
1131         transport->data = data;
1132         transport->vtable = &vtable;
1133         transport->smart_options = &(data->transport_options);
1134         return 0;
1135 }
1136
1137 /*
1138  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1139  * buffer less), so attempt reads and writes with up to that size.
1140  */
1141 #define BUFFERSIZE 65536
1142 /* This should be enough to hold debugging message. */
1143 #define PBUFFERSIZE 8192
1144
1145 /* Print bidirectional transfer loop debug message. */
1146 __attribute__((format (printf, 1, 2)))
1147 static void transfer_debug(const char *fmt, ...)
1148 {
1149         /*
1150          * NEEDSWORK: This function is sometimes used from multiple threads, and
1151          * we end up using debug_enabled racily. That "should not matter" since
1152          * we always write the same value, but it's still wrong. This function
1153          * is listed in .tsan-suppressions for the time being.
1154          */
1155
1156         va_list args;
1157         char msgbuf[PBUFFERSIZE];
1158         static int debug_enabled = -1;
1159
1160         if (debug_enabled < 0)
1161                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1162         if (!debug_enabled)
1163                 return;
1164
1165         va_start(args, fmt);
1166         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1167         va_end(args);
1168         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1169 }
1170
1171 /* Stream state: More data may be coming in this direction. */
1172 #define SSTATE_TRANSFERRING 0
1173 /*
1174  * Stream state: No more data coming in this direction, flushing rest of
1175  * data.
1176  */
1177 #define SSTATE_FLUSHING 1
1178 /* Stream state: Transfer in this direction finished. */
1179 #define SSTATE_FINISHED 2
1180
1181 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1182 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1183 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1184
1185 /* Unidirectional transfer. */
1186 struct unidirectional_transfer {
1187         /* Source */
1188         int src;
1189         /* Destination */
1190         int dest;
1191         /* Is source socket? */
1192         int src_is_sock;
1193         /* Is destination socket? */
1194         int dest_is_sock;
1195         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1196         int state;
1197         /* Buffer. */
1198         char buf[BUFFERSIZE];
1199         /* Buffer used. */
1200         size_t bufuse;
1201         /* Name of source. */
1202         const char *src_name;
1203         /* Name of destination. */
1204         const char *dest_name;
1205 };
1206
1207 /* Closes the target (for writing) if transfer has finished. */
1208 static void udt_close_if_finished(struct unidirectional_transfer *t)
1209 {
1210         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1211                 t->state = SSTATE_FINISHED;
1212                 if (t->dest_is_sock)
1213                         shutdown(t->dest, SHUT_WR);
1214                 else
1215                         close(t->dest);
1216                 transfer_debug("Closed %s.", t->dest_name);
1217         }
1218 }
1219
1220 /*
1221  * Tries to read data from source into buffer. If buffer is full,
1222  * no data is read. Returns 0 on success, -1 on error.
1223  */
1224 static int udt_do_read(struct unidirectional_transfer *t)
1225 {
1226         ssize_t bytes;
1227
1228         if (t->bufuse == BUFFERSIZE)
1229                 return 0;       /* No space for more. */
1230
1231         transfer_debug("%s is readable", t->src_name);
1232         bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1233         if (bytes < 0) {
1234                 error_errno(_("read(%s) failed"), t->src_name);
1235                 return -1;
1236         } else if (bytes == 0) {
1237                 transfer_debug("%s EOF (with %i bytes in buffer)",
1238                         t->src_name, (int)t->bufuse);
1239                 t->state = SSTATE_FLUSHING;
1240         } else if (bytes > 0) {
1241                 t->bufuse += bytes;
1242                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1243                         (int)bytes, t->src_name, (int)t->bufuse);
1244         }
1245         return 0;
1246 }
1247
1248 /* Tries to write data from buffer into destination. If buffer is empty,
1249  * no data is written. Returns 0 on success, -1 on error.
1250  */
1251 static int udt_do_write(struct unidirectional_transfer *t)
1252 {
1253         ssize_t bytes;
1254
1255         if (t->bufuse == 0)
1256                 return 0;       /* Nothing to write. */
1257
1258         transfer_debug("%s is writable", t->dest_name);
1259         bytes = xwrite(t->dest, t->buf, t->bufuse);
1260         if (bytes < 0) {
1261                 error_errno(_("write(%s) failed"), t->dest_name);
1262                 return -1;
1263         } else if (bytes > 0) {
1264                 t->bufuse -= bytes;
1265                 if (t->bufuse)
1266                         memmove(t->buf, t->buf + bytes, t->bufuse);
1267                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1268                         (int)bytes, t->dest_name, (int)t->bufuse);
1269         }
1270         return 0;
1271 }
1272
1273
1274 /* State of bidirectional transfer loop. */
1275 struct bidirectional_transfer_state {
1276         /* Direction from program to git. */
1277         struct unidirectional_transfer ptg;
1278         /* Direction from git to program. */
1279         struct unidirectional_transfer gtp;
1280 };
1281
1282 static void *udt_copy_task_routine(void *udt)
1283 {
1284         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1285         while (t->state != SSTATE_FINISHED) {
1286                 if (STATE_NEEDS_READING(t->state))
1287                         if (udt_do_read(t))
1288                                 return NULL;
1289                 if (STATE_NEEDS_WRITING(t->state))
1290                         if (udt_do_write(t))
1291                                 return NULL;
1292                 if (STATE_NEEDS_CLOSING(t->state))
1293                         udt_close_if_finished(t);
1294         }
1295         return udt;     /* Just some non-NULL value. */
1296 }
1297
1298 #ifndef NO_PTHREADS
1299
1300 /*
1301  * Join thread, with appropriate errors on failure. Name is name for the
1302  * thread (for error messages). Returns 0 on success, 1 on failure.
1303  */
1304 static int tloop_join(pthread_t thread, const char *name)
1305 {
1306         int err;
1307         void *tret;
1308         err = pthread_join(thread, &tret);
1309         if (!tret) {
1310                 error(_("%s thread failed"), name);
1311                 return 1;
1312         }
1313         if (err) {
1314                 error(_("%s thread failed to join: %s"), name, strerror(err));
1315                 return 1;
1316         }
1317         return 0;
1318 }
1319
1320 /*
1321  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1322  * -1 on failure.
1323  */
1324 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1325 {
1326         pthread_t gtp_thread;
1327         pthread_t ptg_thread;
1328         int err;
1329         int ret = 0;
1330         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1331                 &s->gtp);
1332         if (err)
1333                 die(_("can't start thread for copying data: %s"), strerror(err));
1334         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1335                 &s->ptg);
1336         if (err)
1337                 die(_("can't start thread for copying data: %s"), strerror(err));
1338
1339         ret |= tloop_join(gtp_thread, "Git to program copy");
1340         ret |= tloop_join(ptg_thread, "Program to git copy");
1341         return ret;
1342 }
1343 #else
1344
1345 /* Close the source and target (for writing) for transfer. */
1346 static void udt_kill_transfer(struct unidirectional_transfer *t)
1347 {
1348         t->state = SSTATE_FINISHED;
1349         /*
1350          * Socket read end left open isn't a disaster if nobody
1351          * attempts to read from it (mingw compat headers do not
1352          * have SHUT_RD)...
1353          *
1354          * We can't fully close the socket since otherwise gtp
1355          * task would first close the socket it sends data to
1356          * while closing the ptg file descriptors.
1357          */
1358         if (!t->src_is_sock)
1359                 close(t->src);
1360         if (t->dest_is_sock)
1361                 shutdown(t->dest, SHUT_WR);
1362         else
1363                 close(t->dest);
1364 }
1365
1366 /*
1367  * Join process, with appropriate errors on failure. Name is name for the
1368  * process (for error messages). Returns 0 on success, 1 on failure.
1369  */
1370 static int tloop_join(pid_t pid, const char *name)
1371 {
1372         int tret;
1373         if (waitpid(pid, &tret, 0) < 0) {
1374                 error_errno(_("%s process failed to wait"), name);
1375                 return 1;
1376         }
1377         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1378                 error(_("%s process failed"), name);
1379                 return 1;
1380         }
1381         return 0;
1382 }
1383
1384 /*
1385  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1386  * -1 on failure.
1387  */
1388 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1389 {
1390         pid_t pid1, pid2;
1391         int ret = 0;
1392
1393         /* Fork thread #1: git to program. */
1394         pid1 = fork();
1395         if (pid1 < 0)
1396                 die_errno(_("can't start thread for copying data"));
1397         else if (pid1 == 0) {
1398                 udt_kill_transfer(&s->ptg);
1399                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1400         }
1401
1402         /* Fork thread #2: program to git. */
1403         pid2 = fork();
1404         if (pid2 < 0)
1405                 die_errno(_("can't start thread for copying data"));
1406         else if (pid2 == 0) {
1407                 udt_kill_transfer(&s->gtp);
1408                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1409         }
1410
1411         /*
1412          * Close both streams in parent as to not interfere with
1413          * end of file detection and wait for both tasks to finish.
1414          */
1415         udt_kill_transfer(&s->gtp);
1416         udt_kill_transfer(&s->ptg);
1417         ret |= tloop_join(pid1, "Git to program copy");
1418         ret |= tloop_join(pid2, "Program to git copy");
1419         return ret;
1420 }
1421 #endif
1422
1423 /*
1424  * Copies data from stdin to output and from input to stdout simultaneously.
1425  * Additionally filtering through given filter. If filter is NULL, uses
1426  * identity filter.
1427  */
1428 int bidirectional_transfer_loop(int input, int output)
1429 {
1430         struct bidirectional_transfer_state state;
1431
1432         /* Fill the state fields. */
1433         state.ptg.src = input;
1434         state.ptg.dest = 1;
1435         state.ptg.src_is_sock = (input == output);
1436         state.ptg.dest_is_sock = 0;
1437         state.ptg.state = SSTATE_TRANSFERRING;
1438         state.ptg.bufuse = 0;
1439         state.ptg.src_name = "remote input";
1440         state.ptg.dest_name = "stdout";
1441
1442         state.gtp.src = 0;
1443         state.gtp.dest = output;
1444         state.gtp.src_is_sock = 0;
1445         state.gtp.dest_is_sock = (input == output);
1446         state.gtp.state = SSTATE_TRANSFERRING;
1447         state.gtp.bufuse = 0;
1448         state.gtp.src_name = "stdin";
1449         state.gtp.dest_name = "remote output";
1450
1451         return tloop_spawnwait_tasks(&state);
1452 }