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