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