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