transport-helper.c

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