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

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "remote.h"
   9 #include "string-list.h"
  10 #include "thread-utils.h"
  11 #include "sigchain.h"
  12 #include "argv-array.h"
  13 #include "refs.h"
  14 #include "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, debug ? "--stats" : "--quiet");
 436
 437         if (data->bidi_import) {
 438                 cat_blob_fd = xdup(helper->in);
 439                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 440         }
 441         fastimport->git_cmd = 1;
 442
 443         code = start_command(fastimport);
 444         return code;
 445 }
 446
 447 static int get_exporter(struct transport *transport,
 448                         struct child_process *fastexport,
 449                         struct string_list *revlist_args)
 450 {
 451         struct helper_data *data = transport->data;
 452         struct child_process *helper = get_helper(transport);
 453         int i;
 454
 455         child_process_init(fastexport);
 456
 457         /* we need to duplicate helper->in because we want to use it after
 458          * fastexport is done with it. */
 459         fastexport->out = dup(helper->in);
 460         argv_array_push(&fastexport->args, "fast-export");
 461         argv_array_push(&fastexport->args, "--use-done-feature");
 462         argv_array_push(&fastexport->args, data->signed_tags ?
 463                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 464         if (data->export_marks)
 465                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 466         if (data->import_marks)
 467                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 468
 469         for (i = 0; i < revlist_args->nr; i++)
 470                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 471
 472         fastexport->git_cmd = 1;
 473         return start_command(fastexport);
 474 }
 475
 476 static int fetch_with_import(struct transport *transport,
 477                              int nr_heads, struct ref **to_fetch)
 478 {
 479         struct child_process fastimport;
 480         struct helper_data *data = transport->data;
 481         int i;
 482         struct ref *posn;
 483         struct strbuf buf = STRBUF_INIT;
 484
 485         get_helper(transport);
 486
 487         if (get_importer(transport, &fastimport))
 488                 die("Couldn't run fast-import");
 489
 490         for (i = 0; i < nr_heads; i++) {
 491                 posn = to_fetch[i];
 492                 if (posn->status & REF_STATUS_UPTODATE)
 493                         continue;
 494
 495                 strbuf_addf(&buf, "import %s\n",
 496                             posn->symref ? posn->symref : posn->name);
 497                 sendline(data, &buf);
 498                 strbuf_reset(&buf);
 499         }
 500
 501         write_constant(data->helper->in, "\n");
 502         /*
 503          * remote-helpers that advertise the bidi-import capability are required to
 504          * buffer the complete batch of import commands until this newline before
 505          * sending data to fast-import.
 506          * These helpers read back data from fast-import on their stdin, which could
 507          * be mixed with import commands, otherwise.
 508          */
 509
 510         if (finish_command(&fastimport))
 511                 die("Error while running fast-import");
 512
 513         /*
 514          * The fast-import stream of a remote helper that advertises
 515          * the "refspec" capability writes to the refs named after the
 516          * right hand side of the first refspec matching each ref we
 517          * were fetching.
 518          *
 519          * (If no "refspec" capability was specified, for historical
 520          * reasons we default to the equivalent of *:*.)
 521          *
 522          * Store the result in to_fetch[i].old_sha1.  Callers such
 523          * as "git fetch" can use the value to write feedback to the
 524          * terminal, populate FETCH_HEAD, and determine what new value
 525          * should be written to peer_ref if the update is a
 526          * fast-forward or this is a forced update.
 527          */
 528         for (i = 0; i < nr_heads; i++) {
 529                 char *private, *name;
 530                 posn = to_fetch[i];
 531                 if (posn->status & REF_STATUS_UPTODATE)
 532                         continue;
 533                 name = posn->symref ? posn->symref : posn->name;
 534                 if (data->refspecs)
 535                         private = apply_refspecs(data->refspecs, data->refspec_nr, name);
 536                 else
 537                         private = xstrdup(name);
 538                 if (private) {
 539                         if (read_ref(private, &posn->old_oid) < 0)
 540                                 die("Could not read ref %s", private);
 541                         free(private);
 542                 }
 543         }
 544         strbuf_release(&buf);
 545         return 0;
 546 }
 547
 548 static int process_connect_service(struct transport *transport,
 549                                    const char *name, const char *exec)
 550 {
 551         struct helper_data *data = transport->data;
 552         struct strbuf cmdbuf = STRBUF_INIT;
 553         struct child_process *helper;
 554         int r, duped, ret = 0;
 555         FILE *input;
 556
 557         helper = get_helper(transport);
 558
 559         /*
 560          * Yes, dup the pipe another time, as we need unbuffered version
 561          * of input pipe as FILE*. fclose() closes the underlying fd and
 562          * stream buffering only can be changed before first I/O operation
 563          * on it.
 564          */
 565         duped = dup(helper->out);
 566         if (duped < 0)
 567                 die_errno("Can't dup helper output fd");
 568         input = xfdopen(duped, "r");
 569         setvbuf(input, NULL, _IONBF, 0);
 570
 571         /*
 572          * Handle --upload-pack and friends. This is fire and forget...
 573          * just warn if it fails.
 574          */
 575         if (strcmp(name, exec)) {
 576                 r = set_helper_option(transport, "servpath", exec);
 577                 if (r > 0)
 578                         warning("Setting remote service path not supported by protocol.");
 579                 else if (r < 0)
 580                         warning("Invalid remote service path.");
 581         }
 582
 583         if (data->connect)
 584                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 585         else
 586                 goto exit;
 587
 588         sendline(data, &cmdbuf);
 589         if (recvline_fh(input, &cmdbuf, name))
 590                 exit(128);
 591
 592         if (!strcmp(cmdbuf.buf, "")) {
 593                 data->no_disconnect_req = 1;
 594                 if (debug)
 595                         fprintf(stderr, "Debug: Smart transport connection "
 596                                 "ready.\n");
 597                 ret = 1;
 598         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 599                 if (debug)
 600                         fprintf(stderr, "Debug: Falling back to dumb "
 601                                 "transport.\n");
 602         } else
 603                 die("Unknown response to connect: %s",
 604                         cmdbuf.buf);
 605
 606 exit:
 607         strbuf_release(&cmdbuf);
 608         fclose(input);
 609         return ret;
 610 }
 611
 612 static int process_connect(struct transport *transport,
 613                                      int for_push)
 614 {
 615         struct helper_data *data = transport->data;
 616         const char *name;
 617         const char *exec;
 618
 619         name = for_push ? "git-receive-pack" : "git-upload-pack";
 620         if (for_push)
 621                 exec = data->transport_options.receivepack;
 622         else
 623                 exec = data->transport_options.uploadpack;
 624
 625         return process_connect_service(transport, name, exec);
 626 }
 627
 628 static int connect_helper(struct transport *transport, const char *name,
 629                    const char *exec, int fd[2])
 630 {
 631         struct helper_data *data = transport->data;
 632
 633         /* Get_helper so connect is inited. */
 634         get_helper(transport);
 635         if (!data->connect)
 636                 die("Operation not supported by protocol.");
 637
 638         if (!process_connect_service(transport, name, exec))
 639                 die("Can't connect to subservice %s.", name);
 640
 641         fd[0] = data->helper->out;
 642         fd[1] = data->helper->in;
 643         return 0;
 644 }
 645
 646 static int fetch(struct transport *transport,
 647                  int nr_heads, struct ref **to_fetch)
 648 {
 649         struct helper_data *data = transport->data;
 650         int i, count;
 651
 652         if (process_connect(transport, 0)) {
 653                 do_take_over(transport);
 654                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
 655         }
 656
 657         count = 0;
 658         for (i = 0; i < nr_heads; i++)
 659                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 660                         count++;
 661
 662         if (!count)
 663                 return 0;
 664
 665         if (data->check_connectivity &&
 666             data->transport_options.check_self_contained_and_connected)
 667                 set_helper_option(transport, "check-connectivity", "true");
 668
 669         if (transport->cloning)
 670                 set_helper_option(transport, "cloning", "true");
 671
 672         if (data->transport_options.update_shallow)
 673                 set_helper_option(transport, "update-shallow", "true");
 674
 675         if (data->transport_options.filter_options.choice)
 676                 set_helper_option(
 677                         transport, "filter",
 678                         data->transport_options.filter_options.filter_spec);
 679
 680         if (data->fetch)
 681                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 682
 683         if (data->import)
 684                 return fetch_with_import(transport, nr_heads, to_fetch);
 685
 686         return -1;
 687 }
 688
 689 static int push_update_ref_status(struct strbuf *buf,
 690                                    struct ref **ref,
 691                                    struct ref *remote_refs)
 692 {
 693         char *refname, *msg;
 694         int status, forced = 0;
 695
 696         if (starts_with(buf->buf, "ok ")) {
 697                 status = REF_STATUS_OK;
 698                 refname = buf->buf + 3;
 699         } else if (starts_with(buf->buf, "error ")) {
 700                 status = REF_STATUS_REMOTE_REJECT;
 701                 refname = buf->buf + 6;
 702         } else
 703                 die("expected ok/error, helper said '%s'", buf->buf);
 704
 705         msg = strchr(refname, ' ');
 706         if (msg) {
 707                 struct strbuf msg_buf = STRBUF_INIT;
 708                 const char *end;
 709
 710                 *msg++ = '\0';
 711                 if (!unquote_c_style(&msg_buf, msg, &end))
 712                         msg = strbuf_detach(&msg_buf, NULL);
 713                 else
 714                         msg = xstrdup(msg);
 715                 strbuf_release(&msg_buf);
 716
 717                 if (!strcmp(msg, "no match")) {
 718                         status = REF_STATUS_NONE;
 719                         FREE_AND_NULL(msg);
 720                 }
 721                 else if (!strcmp(msg, "up to date")) {
 722                         status = REF_STATUS_UPTODATE;
 723                         FREE_AND_NULL(msg);
 724                 }
 725                 else if (!strcmp(msg, "non-fast forward")) {
 726                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 727                         FREE_AND_NULL(msg);
 728                 }
 729                 else if (!strcmp(msg, "already exists")) {
 730                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 731                         FREE_AND_NULL(msg);
 732                 }
 733                 else if (!strcmp(msg, "fetch first")) {
 734                         status = REF_STATUS_REJECT_FETCH_FIRST;
 735                         FREE_AND_NULL(msg);
 736                 }
 737                 else if (!strcmp(msg, "needs force")) {
 738                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 739                         FREE_AND_NULL(msg);
 740                 }
 741                 else if (!strcmp(msg, "stale info")) {
 742                         status = REF_STATUS_REJECT_STALE;
 743                         FREE_AND_NULL(msg);
 744                 }
 745                 else if (!strcmp(msg, "forced update")) {
 746                         forced = 1;
 747                         FREE_AND_NULL(msg);
 748                 }
 749         }
 750
 751         if (*ref)
 752                 *ref = find_ref_by_name(*ref, refname);
 753         if (!*ref)
 754                 *ref = find_ref_by_name(remote_refs, refname);
 755         if (!*ref) {
 756                 warning("helper reported unexpected status of %s", refname);
 757                 return 1;
 758         }
 759
 760         if ((*ref)->status != REF_STATUS_NONE) {
 761                 /*
 762                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 763                  * status reported by the remote helper if the latter is 'no match'.
 764                  */
 765                 if (status == REF_STATUS_NONE)
 766                         return 1;
 767         }
 768
 769         (*ref)->status = status;
 770         (*ref)->forced_update |= forced;
 771         (*ref)->remote_status = msg;
 772         return !(status == REF_STATUS_OK);
 773 }
 774
 775 static int push_update_refs_status(struct helper_data *data,
 776                                     struct ref *remote_refs,
 777                                     int flags)
 778 {
 779         struct strbuf buf = STRBUF_INIT;
 780         struct ref *ref = remote_refs;
 781         int ret = 0;
 782
 783         for (;;) {
 784                 char *private;
 785
 786                 if (recvline(data, &buf)) {
 787                         ret = 1;
 788                         break;
 789                 }
 790
 791                 if (!buf.len)
 792                         break;
 793
 794                 if (push_update_ref_status(&buf, &ref, remote_refs))
 795                         continue;
 796
 797                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 798                         continue;
 799
 800                 /* propagate back the update to the remote namespace */
 801                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 802                 if (!private)
 803                         continue;
 804                 update_ref("update by helper", private, &ref->new_oid, NULL,
 805                            0, 0);
 806                 free(private);
 807         }
 808         strbuf_release(&buf);
 809         return ret;
 810 }
 811
 812 static void set_common_push_options(struct transport *transport,
 813                                    const char *name, int flags)
 814 {
 815         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 816                 if (set_helper_option(transport, "dry-run", "true") != 0)
 817                         die("helper %s does not support dry-run", name);
 818         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 819                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 820                         die("helper %s does not support --signed", name);
 821         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 822                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 823                         die("helper %s does not support --signed=if-asked", name);
 824         }
 825
 826         if (flags & TRANSPORT_PUSH_OPTIONS) {
 827                 struct string_list_item *item;
 828                 for_each_string_list_item(item, transport->push_options)
 829                         if (set_helper_option(transport, "push-option", item->string) != 0)
 830                                 die("helper %s does not support 'push-option'", name);
 831         }
 832 }
 833
 834 static int push_refs_with_push(struct transport *transport,
 835                                struct ref *remote_refs, int flags)
 836 {
 837         int force_all = flags & TRANSPORT_PUSH_FORCE;
 838         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 839         struct helper_data *data = transport->data;
 840         struct strbuf buf = STRBUF_INIT;
 841         struct ref *ref;
 842         struct string_list cas_options = STRING_LIST_INIT_DUP;
 843         struct string_list_item *cas_option;
 844
 845         get_helper(transport);
 846         if (!data->push)
 847                 return 1;
 848
 849         for (ref = remote_refs; ref; ref = ref->next) {
 850                 if (!ref->peer_ref && !mirror)
 851                         continue;
 852
 853                 /* Check for statuses set by set_ref_status_for_push() */
 854                 switch (ref->status) {
 855                 case REF_STATUS_REJECT_NONFASTFORWARD:
 856                 case REF_STATUS_REJECT_STALE:
 857                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 858                 case REF_STATUS_UPTODATE:
 859                         continue;
 860                 default:
 861                         ; /* do nothing */
 862                 }
 863
 864                 if (force_all)
 865                         ref->force = 1;
 866
 867                 strbuf_addstr(&buf, "push ");
 868                 if (!ref->deletion) {
 869                         if (ref->force)
 870                                 strbuf_addch(&buf, '+');
 871                         if (ref->peer_ref)
 872                                 strbuf_addstr(&buf, ref->peer_ref->name);
 873                         else
 874                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 875                 }
 876                 strbuf_addch(&buf, ':');
 877                 strbuf_addstr(&buf, ref->name);
 878                 strbuf_addch(&buf, '\n');
 879
 880                 /*
 881                  * The "--force-with-lease" options without explicit
 882                  * values to expect have already been expanded into
 883                  * the ref->old_oid_expect[] field; we can ignore
 884                  * transport->smart_options->cas altogether and instead
 885                  * can enumerate them from the refs.
 886                  */
 887                 if (ref->expect_old_sha1) {
 888                         struct strbuf cas = STRBUF_INIT;
 889                         strbuf_addf(&cas, "%s:%s",
 890                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 891                         string_list_append_nodup(&cas_options,
 892                                                  strbuf_detach(&cas, NULL));
 893                 }
 894         }
 895         if (buf.len == 0) {
 896                 string_list_clear(&cas_options, 0);
 897                 return 0;
 898         }
 899
 900         for_each_string_list_item(cas_option, &cas_options)
 901                 set_helper_option(transport, "cas", cas_option->string);
 902         set_common_push_options(transport, data->name, flags);
 903
 904         strbuf_addch(&buf, '\n');
 905         sendline(data, &buf);
 906         strbuf_release(&buf);
 907         string_list_clear(&cas_options, 0);
 908
 909         return push_update_refs_status(data, remote_refs, flags);
 910 }
 911
 912 static int push_refs_with_export(struct transport *transport,
 913                 struct ref *remote_refs, int flags)
 914 {
 915         struct ref *ref;
 916         struct child_process *helper, exporter;
 917         struct helper_data *data = transport->data;
 918         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 919         struct strbuf buf = STRBUF_INIT;
 920
 921         if (!data->refspecs)
 922                 die("remote-helper doesn't support push; refspec needed");
 923
 924         set_common_push_options(transport, data->name, flags);
 925         if (flags & TRANSPORT_PUSH_FORCE) {
 926                 if (set_helper_option(transport, "force", "true") != 0)
 927                         warning("helper %s does not support 'force'", data->name);
 928         }
 929
 930         helper = get_helper(transport);
 931
 932         write_constant(helper->in, "export\n");
 933
 934         for (ref = remote_refs; ref; ref = ref->next) {
 935                 char *private;
 936                 struct object_id oid;
 937
 938                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 939                 if (private && !get_oid(private, &oid)) {
 940                         strbuf_addf(&buf, "^%s", private);
 941                         string_list_append_nodup(&revlist_args,
 942                                                  strbuf_detach(&buf, NULL));
 943                         oidcpy(&ref->old_oid, &oid);
 944                 }
 945                 free(private);
 946
 947                 if (ref->peer_ref) {
 948                         if (strcmp(ref->name, ref->peer_ref->name)) {
 949                                 if (!ref->deletion) {
 950                                         const char *name;
 951                                         int flag;
 952
 953                                         /* Follow symbolic refs (mainly for HEAD). */
 954                                         name = resolve_ref_unsafe(ref->peer_ref->name,
 955                                                                   RESOLVE_REF_READING,
 956                                                                   &oid, &flag);
 957                                         if (!name || !(flag & REF_ISSYMREF))
 958                                                 name = ref->peer_ref->name;
 959
 960                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 961                                 } else
 962                                         strbuf_addf(&buf, ":%s", ref->name);
 963
 964                                 string_list_append(&revlist_args, "--refspec");
 965                                 string_list_append(&revlist_args, buf.buf);
 966                                 strbuf_release(&buf);
 967                         }
 968                         if (!ref->deletion)
 969                                 string_list_append(&revlist_args, ref->peer_ref->name);
 970                 }
 971         }
 972
 973         if (get_exporter(transport, &exporter, &revlist_args))
 974                 die("Couldn't run fast-export");
 975
 976         string_list_clear(&revlist_args, 1);
 977
 978         if (finish_command(&exporter))
 979                 die("Error while running fast-export");
 980         if (push_update_refs_status(data, remote_refs, flags))
 981                 return 1;
 982
 983         if (data->export_marks) {
 984                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 985                 rename(buf.buf, data->export_marks);
 986                 strbuf_release(&buf);
 987         }
 988
 989         return 0;
 990 }
 991
 992 static int push_refs(struct transport *transport,
 993                 struct ref *remote_refs, int flags)
 994 {
 995         struct helper_data *data = transport->data;
 996
 997         if (process_connect(transport, 1)) {
 998                 do_take_over(transport);
 999                 return transport->vtable->push_refs(transport, remote_refs, flags);
1000         }
1001
1002         if (!remote_refs) {
1003                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
1004                         "Perhaps you should specify a branch such as 'master'.\n");
1005                 return 0;
1006         }
1007
1008         if (data->push)
1009                 return push_refs_with_push(transport, remote_refs, flags);
1010
1011         if (data->export)
1012                 return push_refs_with_export(transport, remote_refs, flags);
1013
1014         return -1;
1015 }
1016
1017
1018 static int has_attribute(const char *attrs, const char *attr) {
1019         int len;
1020         if (!attrs)
1021                 return 0;
1022
1023         len = strlen(attr);
1024         for (;;) {
1025                 const char *space = strchrnul(attrs, ' ');
1026                 if (len == space - attrs && !strncmp(attrs, attr, len))
1027                         return 1;
1028                 if (!*space)
1029                         return 0;
1030                 attrs = space + 1;
1031         }
1032 }
1033
1034 static struct ref *get_refs_list(struct transport *transport, int for_push)
1035 {
1036         struct helper_data *data = transport->data;
1037         struct child_process *helper;
1038         struct ref *ret = NULL;
1039         struct ref **tail = &ret;
1040         struct ref *posn;
1041         struct strbuf buf = STRBUF_INIT;
1042
1043         helper = get_helper(transport);
1044
1045         if (process_connect(transport, for_push)) {
1046                 do_take_over(transport);
1047                 return transport->vtable->get_refs_list(transport, for_push);
1048         }
1049
1050         if (data->push && for_push)
1051                 write_str_in_full(helper->in, "list for-push\n");
1052         else
1053                 write_str_in_full(helper->in, "list\n");
1054
1055         while (1) {
1056                 char *eov, *eon;
1057                 if (recvline(data, &buf))
1058                         exit(128);
1059
1060                 if (!*buf.buf)
1061                         break;
1062
1063                 eov = strchr(buf.buf, ' ');
1064                 if (!eov)
1065                         die("Malformed response in ref list: %s", buf.buf);
1066                 eon = strchr(eov + 1, ' ');
1067                 *eov = '\0';
1068                 if (eon)
1069                         *eon = '\0';
1070                 *tail = alloc_ref(eov + 1);
1071                 if (buf.buf[0] == '@')
1072                         (*tail)->symref = xstrdup(buf.buf + 1);
1073                 else if (buf.buf[0] != '?')
1074                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1075                 if (eon) {
1076                         if (has_attribute(eon + 1, "unchanged")) {
1077                                 (*tail)->status |= REF_STATUS_UPTODATE;
1078                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1079                                         die(_("Could not read ref %s"),
1080                                             (*tail)->name);
1081                         }
1082                 }
1083                 tail = &((*tail)->next);
1084         }
1085         if (debug)
1086                 fprintf(stderr, "Debug: Read ref listing.\n");
1087         strbuf_release(&buf);
1088
1089         for (posn = ret; posn; posn = posn->next)
1090                 resolve_remote_symref(posn, ret);
1091
1092         return ret;
1093 }
1094
1095 static struct transport_vtable vtable = {
1096         set_helper_option,
1097         get_refs_list,
1098         fetch,
1099         push_refs,
1100         connect_helper,
1101         release_helper
1102 };
1103
1104 int transport_helper_init(struct transport *transport, const char *name)
1105 {
1106         struct helper_data *data = xcalloc(1, sizeof(*data));
1107         data->name = name;
1108
1109         transport_check_allowed(name);
1110
1111         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1112                 debug = 1;
1113
1114         transport->data = data;
1115         transport->vtable = &vtable;
1116         transport->smart_options = &(data->transport_options);
1117         return 0;
1118 }
1119
1120 /*
1121  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1122  * buffer less), so attempt reads and writes with up to that size.
1123  */
1124 #define BUFFERSIZE 65536
1125 /* This should be enough to hold debugging message. */
1126 #define PBUFFERSIZE 8192
1127
1128 /* Print bidirectional transfer loop debug message. */
1129 __attribute__((format (printf, 1, 2)))
1130 static void transfer_debug(const char *fmt, ...)
1131 {
1132         /*
1133          * NEEDSWORK: This function is sometimes used from multiple threads, and
1134          * we end up using debug_enabled racily. That "should not matter" since
1135          * we always write the same value, but it's still wrong. This function
1136          * is listed in .tsan-suppressions for the time being.
1137          */
1138
1139         va_list args;
1140         char msgbuf[PBUFFERSIZE];
1141         static int debug_enabled = -1;
1142
1143         if (debug_enabled < 0)
1144                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1145         if (!debug_enabled)
1146                 return;
1147
1148         va_start(args, fmt);
1149         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1150         va_end(args);
1151         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1152 }
1153
1154 /* Stream state: More data may be coming in this direction. */
1155 #define SSTATE_TRANSFERRING 0
1156 /*
1157  * Stream state: No more data coming in this direction, flushing rest of
1158  * data.
1159  */
1160 #define SSTATE_FLUSHING 1
1161 /* Stream state: Transfer in this direction finished. */
1162 #define SSTATE_FINISHED 2
1163
1164 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1165 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1166 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1167
1168 /* Unidirectional transfer. */
1169 struct unidirectional_transfer {
1170         /* Source */
1171         int src;
1172         /* Destination */
1173         int dest;
1174         /* Is source socket? */
1175         int src_is_sock;
1176         /* Is destination socket? */
1177         int dest_is_sock;
1178         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1179         int state;
1180         /* Buffer. */
1181         char buf[BUFFERSIZE];
1182         /* Buffer used. */
1183         size_t bufuse;
1184         /* Name of source. */
1185         const char *src_name;
1186         /* Name of destination. */
1187         const char *dest_name;
1188 };
1189
1190 /* Closes the target (for writing) if transfer has finished. */
1191 static void udt_close_if_finished(struct unidirectional_transfer *t)
1192 {
1193         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1194                 t->state = SSTATE_FINISHED;
1195                 if (t->dest_is_sock)
1196                         shutdown(t->dest, SHUT_WR);
1197                 else
1198                         close(t->dest);
1199                 transfer_debug("Closed %s.", t->dest_name);
1200         }
1201 }
1202
1203 /*
1204  * Tries to read data from source into buffer. If buffer is full,
1205  * no data is read. Returns 0 on success, -1 on error.
1206  */
1207 static int udt_do_read(struct unidirectional_transfer *t)
1208 {
1209         ssize_t bytes;
1210
1211         if (t->bufuse == BUFFERSIZE)
1212                 return 0;       /* No space for more. */
1213
1214         transfer_debug("%s is readable", t->src_name);
1215         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1216         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1217                 errno != EINTR) {
1218                 error_errno("read(%s) failed", t->src_name);
1219                 return -1;
1220         } else if (bytes == 0) {
1221                 transfer_debug("%s EOF (with %i bytes in buffer)",
1222                         t->src_name, (int)t->bufuse);
1223                 t->state = SSTATE_FLUSHING;
1224         } else if (bytes > 0) {
1225                 t->bufuse += bytes;
1226                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1227                         (int)bytes, t->src_name, (int)t->bufuse);
1228         }
1229         return 0;
1230 }
1231
1232 /* Tries to write data from buffer into destination. If buffer is empty,
1233  * no data is written. Returns 0 on success, -1 on error.
1234  */
1235 static int udt_do_write(struct unidirectional_transfer *t)
1236 {
1237         ssize_t bytes;
1238
1239         if (t->bufuse == 0)
1240                 return 0;       /* Nothing to write. */
1241
1242         transfer_debug("%s is writable", t->dest_name);
1243         bytes = xwrite(t->dest, t->buf, t->bufuse);
1244         if (bytes < 0 && errno != EWOULDBLOCK) {
1245                 error_errno("write(%s) failed", t->dest_name);
1246                 return -1;
1247         } else if (bytes > 0) {
1248                 t->bufuse -= bytes;
1249                 if (t->bufuse)
1250                         memmove(t->buf, t->buf + bytes, t->bufuse);
1251                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1252                         (int)bytes, t->dest_name, (int)t->bufuse);
1253         }
1254         return 0;
1255 }
1256
1257
1258 /* State of bidirectional transfer loop. */
1259 struct bidirectional_transfer_state {
1260         /* Direction from program to git. */
1261         struct unidirectional_transfer ptg;
1262         /* Direction from git to program. */
1263         struct unidirectional_transfer gtp;
1264 };
1265
1266 static void *udt_copy_task_routine(void *udt)
1267 {
1268         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1269         while (t->state != SSTATE_FINISHED) {
1270                 if (STATE_NEEDS_READING(t->state))
1271                         if (udt_do_read(t))
1272                                 return NULL;
1273                 if (STATE_NEEDS_WRITING(t->state))
1274                         if (udt_do_write(t))
1275                                 return NULL;
1276                 if (STATE_NEEDS_CLOSING(t->state))
1277                         udt_close_if_finished(t);
1278         }
1279         return udt;     /* Just some non-NULL value. */
1280 }
1281
1282 #ifndef NO_PTHREADS
1283
1284 /*
1285  * Join thread, with appropriate errors on failure. Name is name for the
1286  * thread (for error messages). Returns 0 on success, 1 on failure.
1287  */
1288 static int tloop_join(pthread_t thread, const char *name)
1289 {
1290         int err;
1291         void *tret;
1292         err = pthread_join(thread, &tret);
1293         if (!tret) {
1294                 error("%s thread failed", name);
1295                 return 1;
1296         }
1297         if (err) {
1298                 error("%s thread failed to join: %s", name, strerror(err));
1299                 return 1;
1300         }
1301         return 0;
1302 }
1303
1304 /*
1305  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1306  * -1 on failure.
1307  */
1308 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1309 {
1310         pthread_t gtp_thread;
1311         pthread_t ptg_thread;
1312         int err;
1313         int ret = 0;
1314         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1315                 &s->gtp);
1316         if (err)
1317                 die("Can't start thread for copying data: %s", strerror(err));
1318         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1319                 &s->ptg);
1320         if (err)
1321                 die("Can't start thread for copying data: %s", strerror(err));
1322
1323         ret |= tloop_join(gtp_thread, "Git to program copy");
1324         ret |= tloop_join(ptg_thread, "Program to git copy");
1325         return ret;
1326 }
1327 #else
1328
1329 /* Close the source and target (for writing) for transfer. */
1330 static void udt_kill_transfer(struct unidirectional_transfer *t)
1331 {
1332         t->state = SSTATE_FINISHED;
1333         /*
1334          * Socket read end left open isn't a disaster if nobody
1335          * attempts to read from it (mingw compat headers do not
1336          * have SHUT_RD)...
1337          *
1338          * We can't fully close the socket since otherwise gtp
1339          * task would first close the socket it sends data to
1340          * while closing the ptg file descriptors.
1341          */
1342         if (!t->src_is_sock)
1343                 close(t->src);
1344         if (t->dest_is_sock)
1345                 shutdown(t->dest, SHUT_WR);
1346         else
1347                 close(t->dest);
1348 }
1349
1350 /*
1351  * Join process, with appropriate errors on failure. Name is name for the
1352  * process (for error messages). Returns 0 on success, 1 on failure.
1353  */
1354 static int tloop_join(pid_t pid, const char *name)
1355 {
1356         int tret;
1357         if (waitpid(pid, &tret, 0) < 0) {
1358                 error_errno("%s process failed to wait", name);
1359                 return 1;
1360         }
1361         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1362                 error("%s process failed", name);
1363                 return 1;
1364         }
1365         return 0;
1366 }
1367
1368 /*
1369  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1370  * -1 on failure.
1371  */
1372 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1373 {
1374         pid_t pid1, pid2;
1375         int ret = 0;
1376
1377         /* Fork thread #1: git to program. */
1378         pid1 = fork();
1379         if (pid1 < 0)
1380                 die_errno("Can't start thread for copying data");
1381         else if (pid1 == 0) {
1382                 udt_kill_transfer(&s->ptg);
1383                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1384         }
1385
1386         /* Fork thread #2: program to git. */
1387         pid2 = fork();
1388         if (pid2 < 0)
1389                 die_errno("Can't start thread for copying data");
1390         else if (pid2 == 0) {
1391                 udt_kill_transfer(&s->gtp);
1392                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1393         }
1394
1395         /*
1396          * Close both streams in parent as to not interfere with
1397          * end of file detection and wait for both tasks to finish.
1398          */
1399         udt_kill_transfer(&s->gtp);
1400         udt_kill_transfer(&s->ptg);
1401         ret |= tloop_join(pid1, "Git to program copy");
1402         ret |= tloop_join(pid2, "Program to git copy");
1403         return ret;
1404 }
1405 #endif
1406
1407 /*
1408  * Copies data from stdin to output and from input to stdout simultaneously.
1409  * Additionally filtering through given filter. If filter is NULL, uses
1410  * identity filter.
1411  */
1412 int bidirectional_transfer_loop(int input, int output)
1413 {
1414         struct bidirectional_transfer_state state;
1415
1416         /* Fill the state fields. */
1417         state.ptg.src = input;
1418         state.ptg.dest = 1;
1419         state.ptg.src_is_sock = (input == output);
1420         state.ptg.dest_is_sock = 0;
1421         state.ptg.state = SSTATE_TRANSFERRING;
1422         state.ptg.bufuse = 0;
1423         state.ptg.src_name = "remote input";
1424         state.ptg.dest_name = "stdout";
1425
1426         state.gtp.src = 0;
1427         state.gtp.dest = output;
1428         state.gtp.src_is_sock = 0;
1429         state.gtp.dest_is_sock = (input == output);
1430         state.gtp.state = SSTATE_TRANSFERRING;
1431         state.gtp.bufuse = 0;
1432         state.gtp.src_name = "stdin";
1433         state.gtp.dest_name = "remote output";
1434
1435         return tloop_spawnwait_tasks(&state);
1436 }