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

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "remote.h"
   9 #include "string-list.h"
  10 #include "thread-utils.h"
  11 #include "sigchain.h"
  12 #include "argv-array.h"
  13 #include "refs.h"
  14 #include "refspec.h"
  15 #include "transport-internal.h"
  16 #include "protocol.h"
  17
  18 static int debug;
  19
  20 struct helper_data {
  21         const char *name;
  22         struct child_process *helper;
  23         FILE *out;
  24         unsigned fetch : 1,
  25                 import : 1,
  26                 bidi_import : 1,
  27                 export : 1,
  28                 option : 1,
  29                 push : 1,
  30                 connect : 1,
  31                 stateless_connect : 1,
  32                 signed_tags : 1,
  33                 check_connectivity : 1,
  34                 no_disconnect_req : 1,
  35                 no_private_update : 1;
  36         char *export_marks;
  37         char *import_marks;
  38         /* These go from remote name (as in "list") to private name */
  39         struct refspec rs;
  40         /* Transport options for fetch-pack/send-pack (should one of
  41          * those be invoked).
  42          */
  43         struct git_transport_options transport_options;
  44 };
  45
  46 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  47 {
  48         if (debug)
  49                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  50         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
  51                 die_errno("Full write to remote helper failed");
  52 }
  53
  54 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  55 {
  56         strbuf_reset(buffer);
  57         if (debug)
  58                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  59         if (strbuf_getline(buffer, helper) == EOF) {
  60                 if (debug)
  61                         fprintf(stderr, "Debug: Remote helper quit.\n");
  62                 return 1;
  63         }
  64
  65         if (debug)
  66                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  67         return 0;
  68 }
  69
  70 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  71 {
  72         return recvline_fh(helper->out, buffer);
  73 }
  74
  75 static void write_constant(int fd, const char *str)
  76 {
  77         if (debug)
  78                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  79         if (write_in_full(fd, str, strlen(str)) < 0)
  80                 die_errno("Full write to remote helper failed");
  81 }
  82
  83 static const char *remove_ext_force(const char *url)
  84 {
  85         if (url) {
  86                 const char *colon = strchr(url, ':');
  87                 if (colon && colon[1] == ':')
  88                         return colon + 2;
  89         }
  90         return url;
  91 }
  92
  93 static void do_take_over(struct transport *transport)
  94 {
  95         struct helper_data *data;
  96         data = (struct helper_data *)transport->data;
  97         transport_take_over(transport, data->helper);
  98         fclose(data->out);
  99         free(data);
 100 }
 101
 102 static void standard_options(struct transport *t);
 103
 104 static struct child_process *get_helper(struct transport *transport)
 105 {
 106         struct helper_data *data = transport->data;
 107         struct strbuf buf = STRBUF_INIT;
 108         struct child_process *helper;
 109         int duped;
 110         int code;
 111
 112         if (data->helper)
 113                 return data->helper;
 114
 115         helper = xmalloc(sizeof(*helper));
 116         child_process_init(helper);
 117         helper->in = -1;
 118         helper->out = -1;
 119         helper->err = 0;
 120         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 121         argv_array_push(&helper->args, transport->remote->name);
 122         argv_array_push(&helper->args, remove_ext_force(transport->url));
 123         helper->git_cmd = 0;
 124         helper->silent_exec_failure = 1;
 125
 126         if (have_git_dir())
 127                 argv_array_pushf(&helper->env_array, "%s=%s",
 128                                  GIT_DIR_ENVIRONMENT, get_git_dir());
 129
 130         code = start_command(helper);
 131         if (code < 0 && errno == ENOENT)
 132                 die("Unable to find remote helper for '%s'", data->name);
 133         else if (code != 0)
 134                 exit(code);
 135
 136         data->helper = helper;
 137         data->no_disconnect_req = 0;
 138         refspec_init(&data->rs, REFSPEC_FETCH);
 139
 140         /*
 141          * Open the output as FILE* so strbuf_getline_*() family of
 142          * functions can be used.
 143          * Do this with duped fd because fclose() will close the fd,
 144          * and stuff like taking over will require the fd to remain.
 145          */
 146         duped = dup(helper->out);
 147         if (duped < 0)
 148                 die_errno("Can't dup helper output fd");
 149         data->out = xfdopen(duped, "r");
 150
 151         write_constant(helper->in, "capabilities\n");
 152
 153         while (1) {
 154                 const char *capname, *arg;
 155                 int mandatory = 0;
 156                 if (recvline(data, &buf))
 157                         exit(128);
 158
 159                 if (!*buf.buf)
 160                         break;
 161
 162                 if (*buf.buf == '*') {
 163                         capname = buf.buf + 1;
 164                         mandatory = 1;
 165                 } else
 166                         capname = buf.buf;
 167
 168                 if (debug)
 169                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 170                 if (!strcmp(capname, "fetch"))
 171                         data->fetch = 1;
 172                 else if (!strcmp(capname, "option"))
 173                         data->option = 1;
 174                 else if (!strcmp(capname, "push"))
 175                         data->push = 1;
 176                 else if (!strcmp(capname, "import"))
 177                         data->import = 1;
 178                 else if (!strcmp(capname, "bidi-import"))
 179                         data->bidi_import = 1;
 180                 else if (!strcmp(capname, "export"))
 181                         data->export = 1;
 182                 else if (!strcmp(capname, "check-connectivity"))
 183                         data->check_connectivity = 1;
 184                 else if (skip_prefix(capname, "refspec ", &arg)) {
 185                         refspec_append(&data->rs, arg);
 186                 } else if (!strcmp(capname, "connect")) {
 187                         data->connect = 1;
 188                 } else if (!strcmp(capname, "stateless-connect")) {
 189                         data->stateless_connect = 1;
 190                 } else if (!strcmp(capname, "signed-tags")) {
 191                         data->signed_tags = 1;
 192                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 193                         data->export_marks = xstrdup(arg);
 194                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 195                         data->import_marks = xstrdup(arg);
 196                 } else if (starts_with(capname, "no-private-update")) {
 197                         data->no_private_update = 1;
 198                 } else if (mandatory) {
 199                         die("Unknown mandatory capability %s. This remote "
 200                             "helper probably needs newer version of Git.",
 201                             capname);
 202                 }
 203         }
 204         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
 205                 warning("This remote helper should implement refspec capability.");
 206         }
 207         strbuf_release(&buf);
 208         if (debug)
 209                 fprintf(stderr, "Debug: Capabilities complete.\n");
 210         standard_options(transport);
 211         return data->helper;
 212 }
 213
 214 static int disconnect_helper(struct transport *transport)
 215 {
 216         struct helper_data *data = transport->data;
 217         int res = 0;
 218
 219         if (data->helper) {
 220                 if (debug)
 221                         fprintf(stderr, "Debug: Disconnecting.\n");
 222                 if (!data->no_disconnect_req) {
 223                         /*
 224                          * Ignore write errors; there's nothing we can do,
 225                          * since we're about to close the pipe anyway. And the
 226                          * most likely error is EPIPE due to the helper dying
 227                          * to report an error itself.
 228                          */
 229                         sigchain_push(SIGPIPE, SIG_IGN);
 230                         xwrite(data->helper->in, "\n", 1);
 231                         sigchain_pop(SIGPIPE);
 232                 }
 233                 close(data->helper->in);
 234                 close(data->helper->out);
 235                 fclose(data->out);
 236                 res = finish_command(data->helper);
 237                 FREE_AND_NULL(data->helper);
 238         }
 239         return res;
 240 }
 241
 242 static const char *unsupported_options[] = {
 243         TRANS_OPT_UPLOADPACK,
 244         TRANS_OPT_RECEIVEPACK,
 245         TRANS_OPT_THIN,
 246         TRANS_OPT_KEEP
 247         };
 248
 249 static const char *boolean_options[] = {
 250         TRANS_OPT_THIN,
 251         TRANS_OPT_KEEP,
 252         TRANS_OPT_FOLLOWTAGS,
 253         TRANS_OPT_DEEPEN_RELATIVE
 254         };
 255
 256 static int strbuf_set_helper_option(struct helper_data *data,
 257                                     struct strbuf *buf)
 258 {
 259         int ret;
 260
 261         sendline(data, buf);
 262         if (recvline(data, buf))
 263                 exit(128);
 264
 265         if (!strcmp(buf->buf, "ok"))
 266                 ret = 0;
 267         else if (starts_with(buf->buf, "error"))
 268                 ret = -1;
 269         else if (!strcmp(buf->buf, "unsupported"))
 270                 ret = 1;
 271         else {
 272                 warning("%s unexpectedly said: '%s'", data->name, buf->buf);
 273                 ret = 1;
 274         }
 275         return ret;
 276 }
 277
 278 static int string_list_set_helper_option(struct helper_data *data,
 279                                          const char *name,
 280                                          struct string_list *list)
 281 {
 282         struct strbuf buf = STRBUF_INIT;
 283         int i, ret = 0;
 284
 285         for (i = 0; i < list->nr; i++) {
 286                 strbuf_addf(&buf, "option %s ", name);
 287                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 288                 strbuf_addch(&buf, '\n');
 289
 290                 if ((ret = strbuf_set_helper_option(data, &buf)))
 291                         break;
 292                 strbuf_reset(&buf);
 293         }
 294         strbuf_release(&buf);
 295         return ret;
 296 }
 297
 298 static int set_helper_option(struct transport *transport,
 299                           const char *name, const char *value)
 300 {
 301         struct helper_data *data = transport->data;
 302         struct strbuf buf = STRBUF_INIT;
 303         int i, ret, is_bool = 0;
 304
 305         get_helper(transport);
 306
 307         if (!data->option)
 308                 return 1;
 309
 310         if (!strcmp(name, "deepen-not"))
 311                 return string_list_set_helper_option(data, name,
 312                                                      (struct string_list *)value);
 313
 314         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 315                 if (!strcmp(name, unsupported_options[i]))
 316                         return 1;
 317         }
 318
 319         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 320                 if (!strcmp(name, boolean_options[i])) {
 321                         is_bool = 1;
 322                         break;
 323                 }
 324         }
 325
 326         strbuf_addf(&buf, "option %s ", name);
 327         if (is_bool)
 328                 strbuf_addstr(&buf, value ? "true" : "false");
 329         else
 330                 quote_c_style(value, &buf, NULL, 0);
 331         strbuf_addch(&buf, '\n');
 332
 333         ret = strbuf_set_helper_option(data, &buf);
 334         strbuf_release(&buf);
 335         return ret;
 336 }
 337
 338 static void standard_options(struct transport *t)
 339 {
 340         char buf[16];
 341         int v = t->verbose;
 342
 343         set_helper_option(t, "progress", t->progress ? "true" : "false");
 344
 345         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 346         set_helper_option(t, "verbosity", buf);
 347
 348         switch (t->family) {
 349         case TRANSPORT_FAMILY_ALL:
 350                 /*
 351                  * this is already the default,
 352                  * do not break old remote helpers by setting "all" here
 353                  */
 354                 break;
 355         case TRANSPORT_FAMILY_IPV4:
 356                 set_helper_option(t, "family", "ipv4");
 357                 break;
 358         case TRANSPORT_FAMILY_IPV6:
 359                 set_helper_option(t, "family", "ipv6");
 360                 break;
 361         }
 362 }
 363
 364 static int release_helper(struct transport *transport)
 365 {
 366         int res = 0;
 367         struct helper_data *data = transport->data;
 368         refspec_clear(&data->rs);
 369         res = disconnect_helper(transport);
 370         free(transport->data);
 371         return res;
 372 }
 373
 374 static int fetch_with_fetch(struct transport *transport,
 375                             int nr_heads, struct ref **to_fetch)
 376 {
 377         struct helper_data *data = transport->data;
 378         int i;
 379         struct strbuf buf = STRBUF_INIT;
 380
 381         for (i = 0; i < nr_heads; i++) {
 382                 const struct ref *posn = to_fetch[i];
 383                 if (posn->status & REF_STATUS_UPTODATE)
 384                         continue;
 385
 386                 strbuf_addf(&buf, "fetch %s %s\n",
 387                             oid_to_hex(&posn->old_oid),
 388                             posn->symref ? posn->symref : posn->name);
 389         }
 390
 391         strbuf_addch(&buf, '\n');
 392         sendline(data, &buf);
 393
 394         while (1) {
 395                 if (recvline(data, &buf))
 396                         exit(128);
 397
 398                 if (starts_with(buf.buf, "lock ")) {
 399                         const char *name = buf.buf + 5;
 400                         if (transport->pack_lockfile)
 401                                 warning("%s also locked %s", data->name, name);
 402                         else
 403                                 transport->pack_lockfile = xstrdup(name);
 404                 }
 405                 else if (data->check_connectivity &&
 406                          data->transport_options.check_self_contained_and_connected &&
 407                          !strcmp(buf.buf, "connectivity-ok"))
 408                         data->transport_options.self_contained_and_connected = 1;
 409                 else if (!buf.len)
 410                         break;
 411                 else
 412                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 413         }
 414         strbuf_release(&buf);
 415         return 0;
 416 }
 417
 418 static int get_importer(struct transport *transport, struct child_process *fastimport)
 419 {
 420         struct child_process *helper = get_helper(transport);
 421         struct helper_data *data = transport->data;
 422         int cat_blob_fd, code;
 423         child_process_init(fastimport);
 424         fastimport->in = helper->out;
 425         argv_array_push(&fastimport->args, "fast-import");
 426         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 427
 428         if (data->bidi_import) {
 429                 cat_blob_fd = xdup(helper->in);
 430                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 431         }
 432         fastimport->git_cmd = 1;
 433
 434         code = start_command(fastimport);
 435         return code;
 436 }
 437
 438 static int get_exporter(struct transport *transport,
 439                         struct child_process *fastexport,
 440                         struct string_list *revlist_args)
 441 {
 442         struct helper_data *data = transport->data;
 443         struct child_process *helper = get_helper(transport);
 444         int i;
 445
 446         child_process_init(fastexport);
 447
 448         /* we need to duplicate helper->in because we want to use it after
 449          * fastexport is done with it. */
 450         fastexport->out = dup(helper->in);
 451         argv_array_push(&fastexport->args, "fast-export");
 452         argv_array_push(&fastexport->args, "--use-done-feature");
 453         argv_array_push(&fastexport->args, data->signed_tags ?
 454                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 455         if (data->export_marks)
 456                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 457         if (data->import_marks)
 458                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 459
 460         for (i = 0; i < revlist_args->nr; i++)
 461                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 462
 463         fastexport->git_cmd = 1;
 464         return start_command(fastexport);
 465 }
 466
 467 static int fetch_with_import(struct transport *transport,
 468                              int nr_heads, struct ref **to_fetch)
 469 {
 470         struct child_process fastimport;
 471         struct helper_data *data = transport->data;
 472         int i;
 473         struct ref *posn;
 474         struct strbuf buf = STRBUF_INIT;
 475
 476         get_helper(transport);
 477
 478         if (get_importer(transport, &fastimport))
 479                 die("Couldn't run fast-import");
 480
 481         for (i = 0; i < nr_heads; i++) {
 482                 posn = to_fetch[i];
 483                 if (posn->status & REF_STATUS_UPTODATE)
 484                         continue;
 485
 486                 strbuf_addf(&buf, "import %s\n",
 487                             posn->symref ? posn->symref : posn->name);
 488                 sendline(data, &buf);
 489                 strbuf_reset(&buf);
 490         }
 491
 492         write_constant(data->helper->in, "\n");
 493         /*
 494          * remote-helpers that advertise the bidi-import capability are required to
 495          * buffer the complete batch of import commands until this newline before
 496          * sending data to fast-import.
 497          * These helpers read back data from fast-import on their stdin, which could
 498          * be mixed with import commands, otherwise.
 499          */
 500
 501         if (finish_command(&fastimport))
 502                 die("Error while running fast-import");
 503
 504         /*
 505          * The fast-import stream of a remote helper that advertises
 506          * the "refspec" capability writes to the refs named after the
 507          * right hand side of the first refspec matching each ref we
 508          * were fetching.
 509          *
 510          * (If no "refspec" capability was specified, for historical
 511          * reasons we default to the equivalent of *:*.)
 512          *
 513          * Store the result in to_fetch[i].old_sha1.  Callers such
 514          * as "git fetch" can use the value to write feedback to the
 515          * terminal, populate FETCH_HEAD, and determine what new value
 516          * should be written to peer_ref if the update is a
 517          * fast-forward or this is a forced update.
 518          */
 519         for (i = 0; i < nr_heads; i++) {
 520                 char *private, *name;
 521                 posn = to_fetch[i];
 522                 if (posn->status & REF_STATUS_UPTODATE)
 523                         continue;
 524                 name = posn->symref ? posn->symref : posn->name;
 525                 if (data->rs.nr)
 526                         private = apply_refspecs(&data->rs, name);
 527                 else
 528                         private = xstrdup(name);
 529                 if (private) {
 530                         if (read_ref(private, &posn->old_oid) < 0)
 531                                 die("Could not read ref %s", private);
 532                         free(private);
 533                 }
 534         }
 535         strbuf_release(&buf);
 536         return 0;
 537 }
 538
 539 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 540 {
 541         struct helper_data *data = transport->data;
 542         int ret = 0;
 543         int duped;
 544         FILE *input;
 545         struct child_process *helper;
 546
 547         helper = get_helper(transport);
 548
 549         /*
 550          * Yes, dup the pipe another time, as we need unbuffered version
 551          * of input pipe as FILE*. fclose() closes the underlying fd and
 552          * stream buffering only can be changed before first I/O operation
 553          * on it.
 554          */
 555         duped = dup(helper->out);
 556         if (duped < 0)
 557                 die_errno("Can't dup helper output fd");
 558         input = xfdopen(duped, "r");
 559         setvbuf(input, NULL, _IONBF, 0);
 560
 561         sendline(data, cmdbuf);
 562         if (recvline_fh(input, cmdbuf))
 563                 exit(128);
 564
 565         if (!strcmp(cmdbuf->buf, "")) {
 566                 data->no_disconnect_req = 1;
 567                 if (debug)
 568                         fprintf(stderr, "Debug: Smart transport connection "
 569                                 "ready.\n");
 570                 ret = 1;
 571         } else if (!strcmp(cmdbuf->buf, "fallback")) {
 572                 if (debug)
 573                         fprintf(stderr, "Debug: Falling back to dumb "
 574                                 "transport.\n");
 575         } else {
 576                 die("Unknown response to connect: %s",
 577                         cmdbuf->buf);
 578         }
 579
 580         fclose(input);
 581         return ret;
 582 }
 583
 584 static int process_connect_service(struct transport *transport,
 585                                    const char *name, const char *exec)
 586 {
 587         struct helper_data *data = transport->data;
 588         struct strbuf cmdbuf = STRBUF_INIT;
 589         int ret = 0;
 590
 591         /*
 592          * Handle --upload-pack and friends. This is fire and forget...
 593          * just warn if it fails.
 594          */
 595         if (strcmp(name, exec)) {
 596                 int r = set_helper_option(transport, "servpath", exec);
 597                 if (r > 0)
 598                         warning("Setting remote service path not supported by protocol.");
 599                 else if (r < 0)
 600                         warning("Invalid remote service path.");
 601         }
 602
 603         if (data->connect) {
 604                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 605                 ret = run_connect(transport, &cmdbuf);
 606         } else if (data->stateless_connect &&
 607                    (get_protocol_version_config() == protocol_v2) &&
 608                    !strcmp("git-upload-pack", name)) {
 609                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 610                 ret = run_connect(transport, &cmdbuf);
 611                 if (ret)
 612                         transport->stateless_rpc = 1;
 613         }
 614
 615         strbuf_release(&cmdbuf);
 616         return ret;
 617 }
 618
 619 static int process_connect(struct transport *transport,
 620                                      int for_push)
 621 {
 622         struct helper_data *data = transport->data;
 623         const char *name;
 624         const char *exec;
 625
 626         name = for_push ? "git-receive-pack" : "git-upload-pack";
 627         if (for_push)
 628                 exec = data->transport_options.receivepack;
 629         else
 630                 exec = data->transport_options.uploadpack;
 631
 632         return process_connect_service(transport, name, exec);
 633 }
 634
 635 static int connect_helper(struct transport *transport, const char *name,
 636                    const char *exec, int fd[2])
 637 {
 638         struct helper_data *data = transport->data;
 639
 640         /* Get_helper so connect is inited. */
 641         get_helper(transport);
 642         if (!data->connect)
 643                 die("Operation not supported by protocol.");
 644
 645         if (!process_connect_service(transport, name, exec))
 646                 die("Can't connect to subservice %s.", name);
 647
 648         fd[0] = data->helper->out;
 649         fd[1] = data->helper->in;
 650         return 0;
 651 }
 652
 653 static int fetch(struct transport *transport,
 654                  int nr_heads, struct ref **to_fetch,
 655                  struct ref **fetched_refs)
 656 {
 657         struct helper_data *data = transport->data;
 658         int i, count;
 659
 660         if (process_connect(transport, 0)) {
 661                 do_take_over(transport);
 662                 return transport->vtable->fetch(transport, nr_heads, to_fetch,
 663                                                 fetched_refs);
 664         }
 665
 666         count = 0;
 667         for (i = 0; i < nr_heads; i++)
 668                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 669                         count++;
 670
 671         if (!count)
 672                 return 0;
 673
 674         if (data->check_connectivity &&
 675             data->transport_options.check_self_contained_and_connected)
 676                 set_helper_option(transport, "check-connectivity", "true");
 677
 678         if (transport->cloning)
 679                 set_helper_option(transport, "cloning", "true");
 680
 681         if (data->transport_options.update_shallow)
 682                 set_helper_option(transport, "update-shallow", "true");
 683
 684         if (data->transport_options.filter_options.choice)
 685                 set_helper_option(
 686                         transport, "filter",
 687                         data->transport_options.filter_options.filter_spec);
 688
 689         if (data->transport_options.negotiation_tips)
 690                 warning("Ignoring --negotiation-tip because the protocol does not support it.");
 691
 692         if (data->fetch)
 693                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 694
 695         if (data->import)
 696                 return fetch_with_import(transport, nr_heads, to_fetch);
 697
 698         return -1;
 699 }
 700
 701 static int push_update_ref_status(struct strbuf *buf,
 702                                    struct ref **ref,
 703                                    struct ref *remote_refs)
 704 {
 705         char *refname, *msg;
 706         int status, forced = 0;
 707
 708         if (starts_with(buf->buf, "ok ")) {
 709                 status = REF_STATUS_OK;
 710                 refname = buf->buf + 3;
 711         } else if (starts_with(buf->buf, "error ")) {
 712                 status = REF_STATUS_REMOTE_REJECT;
 713                 refname = buf->buf + 6;
 714         } else
 715                 die("expected ok/error, helper said '%s'", buf->buf);
 716
 717         msg = strchr(refname, ' ');
 718         if (msg) {
 719                 struct strbuf msg_buf = STRBUF_INIT;
 720                 const char *end;
 721
 722                 *msg++ = '\0';
 723                 if (!unquote_c_style(&msg_buf, msg, &end))
 724                         msg = strbuf_detach(&msg_buf, NULL);
 725                 else
 726                         msg = xstrdup(msg);
 727                 strbuf_release(&msg_buf);
 728
 729                 if (!strcmp(msg, "no match")) {
 730                         status = REF_STATUS_NONE;
 731                         FREE_AND_NULL(msg);
 732                 }
 733                 else if (!strcmp(msg, "up to date")) {
 734                         status = REF_STATUS_UPTODATE;
 735                         FREE_AND_NULL(msg);
 736                 }
 737                 else if (!strcmp(msg, "non-fast forward")) {
 738                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 739                         FREE_AND_NULL(msg);
 740                 }
 741                 else if (!strcmp(msg, "already exists")) {
 742                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 743                         FREE_AND_NULL(msg);
 744                 }
 745                 else if (!strcmp(msg, "fetch first")) {
 746                         status = REF_STATUS_REJECT_FETCH_FIRST;
 747                         FREE_AND_NULL(msg);
 748                 }
 749                 else if (!strcmp(msg, "needs force")) {
 750                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 751                         FREE_AND_NULL(msg);
 752                 }
 753                 else if (!strcmp(msg, "stale info")) {
 754                         status = REF_STATUS_REJECT_STALE;
 755                         FREE_AND_NULL(msg);
 756                 }
 757                 else if (!strcmp(msg, "forced update")) {
 758                         forced = 1;
 759                         FREE_AND_NULL(msg);
 760                 }
 761         }
 762
 763         if (*ref)
 764                 *ref = find_ref_by_name(*ref, refname);
 765         if (!*ref)
 766                 *ref = find_ref_by_name(remote_refs, refname);
 767         if (!*ref) {
 768                 warning("helper reported unexpected status of %s", refname);
 769                 return 1;
 770         }
 771
 772         if ((*ref)->status != REF_STATUS_NONE) {
 773                 /*
 774                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 775                  * status reported by the remote helper if the latter is 'no match'.
 776                  */
 777                 if (status == REF_STATUS_NONE)
 778                         return 1;
 779         }
 780
 781         (*ref)->status = status;
 782         (*ref)->forced_update |= forced;
 783         (*ref)->remote_status = msg;
 784         return !(status == REF_STATUS_OK);
 785 }
 786
 787 static int push_update_refs_status(struct helper_data *data,
 788                                     struct ref *remote_refs,
 789                                     int flags)
 790 {
 791         struct strbuf buf = STRBUF_INIT;
 792         struct ref *ref = remote_refs;
 793         int ret = 0;
 794
 795         for (;;) {
 796                 char *private;
 797
 798                 if (recvline(data, &buf)) {
 799                         ret = 1;
 800                         break;
 801                 }
 802
 803                 if (!buf.len)
 804                         break;
 805
 806                 if (push_update_ref_status(&buf, &ref, remote_refs))
 807                         continue;
 808
 809                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
 810                         continue;
 811
 812                 /* propagate back the update to the remote namespace */
 813                 private = apply_refspecs(&data->rs, ref->name);
 814                 if (!private)
 815                         continue;
 816                 update_ref("update by helper", private, &ref->new_oid, NULL,
 817                            0, 0);
 818                 free(private);
 819         }
 820         strbuf_release(&buf);
 821         return ret;
 822 }
 823
 824 static void set_common_push_options(struct transport *transport,
 825                                    const char *name, int flags)
 826 {
 827         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 828                 if (set_helper_option(transport, "dry-run", "true") != 0)
 829                         die("helper %s does not support dry-run", name);
 830         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 831                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 832                         die("helper %s does not support --signed", name);
 833         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 834                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 835                         die("helper %s does not support --signed=if-asked", name);
 836         }
 837
 838         if (flags & TRANSPORT_PUSH_OPTIONS) {
 839                 struct string_list_item *item;
 840                 for_each_string_list_item(item, transport->push_options)
 841                         if (set_helper_option(transport, "push-option", item->string) != 0)
 842                                 die("helper %s does not support 'push-option'", name);
 843         }
 844 }
 845
 846 static int push_refs_with_push(struct transport *transport,
 847                                struct ref *remote_refs, int flags)
 848 {
 849         int force_all = flags & TRANSPORT_PUSH_FORCE;
 850         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 851         struct helper_data *data = transport->data;
 852         struct strbuf buf = STRBUF_INIT;
 853         struct ref *ref;
 854         struct string_list cas_options = STRING_LIST_INIT_DUP;
 855         struct string_list_item *cas_option;
 856
 857         get_helper(transport);
 858         if (!data->push)
 859                 return 1;
 860
 861         for (ref = remote_refs; ref; ref = ref->next) {
 862                 if (!ref->peer_ref && !mirror)
 863                         continue;
 864
 865                 /* Check for statuses set by set_ref_status_for_push() */
 866                 switch (ref->status) {
 867                 case REF_STATUS_REJECT_NONFASTFORWARD:
 868                 case REF_STATUS_REJECT_STALE:
 869                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 870                 case REF_STATUS_UPTODATE:
 871                         continue;
 872                 default:
 873                         ; /* do nothing */
 874                 }
 875
 876                 if (force_all)
 877                         ref->force = 1;
 878
 879                 strbuf_addstr(&buf, "push ");
 880                 if (!ref->deletion) {
 881                         if (ref->force)
 882                                 strbuf_addch(&buf, '+');
 883                         if (ref->peer_ref)
 884                                 strbuf_addstr(&buf, ref->peer_ref->name);
 885                         else
 886                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 887                 }
 888                 strbuf_addch(&buf, ':');
 889                 strbuf_addstr(&buf, ref->name);
 890                 strbuf_addch(&buf, '\n');
 891
 892                 /*
 893                  * The "--force-with-lease" options without explicit
 894                  * values to expect have already been expanded into
 895                  * the ref->old_oid_expect[] field; we can ignore
 896                  * transport->smart_options->cas altogether and instead
 897                  * can enumerate them from the refs.
 898                  */
 899                 if (ref->expect_old_sha1) {
 900                         struct strbuf cas = STRBUF_INIT;
 901                         strbuf_addf(&cas, "%s:%s",
 902                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 903                         string_list_append_nodup(&cas_options,
 904                                                  strbuf_detach(&cas, NULL));
 905                 }
 906         }
 907         if (buf.len == 0) {
 908                 string_list_clear(&cas_options, 0);
 909                 return 0;
 910         }
 911
 912         for_each_string_list_item(cas_option, &cas_options)
 913                 set_helper_option(transport, "cas", cas_option->string);
 914         set_common_push_options(transport, data->name, flags);
 915
 916         strbuf_addch(&buf, '\n');
 917         sendline(data, &buf);
 918         strbuf_release(&buf);
 919         string_list_clear(&cas_options, 0);
 920
 921         return push_update_refs_status(data, remote_refs, flags);
 922 }
 923
 924 static int push_refs_with_export(struct transport *transport,
 925                 struct ref *remote_refs, int flags)
 926 {
 927         struct ref *ref;
 928         struct child_process *helper, exporter;
 929         struct helper_data *data = transport->data;
 930         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 931         struct strbuf buf = STRBUF_INIT;
 932
 933         if (!data->rs.nr)
 934                 die("remote-helper doesn't support push; refspec needed");
 935
 936         set_common_push_options(transport, data->name, flags);
 937         if (flags & TRANSPORT_PUSH_FORCE) {
 938                 if (set_helper_option(transport, "force", "true") != 0)
 939                         warning("helper %s does not support 'force'", data->name);
 940         }
 941
 942         helper = get_helper(transport);
 943
 944         write_constant(helper->in, "export\n");
 945
 946         for (ref = remote_refs; ref; ref = ref->next) {
 947                 char *private;
 948                 struct object_id oid;
 949
 950                 private = apply_refspecs(&data->rs, ref->name);
 951                 if (private && !get_oid(private, &oid)) {
 952                         strbuf_addf(&buf, "^%s", private);
 953                         string_list_append_nodup(&revlist_args,
 954                                                  strbuf_detach(&buf, NULL));
 955                         oidcpy(&ref->old_oid, &oid);
 956                 }
 957                 free(private);
 958
 959                 if (ref->peer_ref) {
 960                         if (strcmp(ref->name, ref->peer_ref->name)) {
 961                                 if (!ref->deletion) {
 962                                         const char *name;
 963                                         int flag;
 964
 965                                         /* Follow symbolic refs (mainly for HEAD). */
 966                                         name = resolve_ref_unsafe(ref->peer_ref->name,
 967                                                                   RESOLVE_REF_READING,
 968                                                                   &oid, &flag);
 969                                         if (!name || !(flag & REF_ISSYMREF))
 970                                                 name = ref->peer_ref->name;
 971
 972                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 973                                 } else
 974                                         strbuf_addf(&buf, ":%s", ref->name);
 975
 976                                 string_list_append(&revlist_args, "--refspec");
 977                                 string_list_append(&revlist_args, buf.buf);
 978                                 strbuf_release(&buf);
 979                         }
 980                         if (!ref->deletion)
 981                                 string_list_append(&revlist_args, ref->peer_ref->name);
 982                 }
 983         }
 984
 985         if (get_exporter(transport, &exporter, &revlist_args))
 986                 die("Couldn't run fast-export");
 987
 988         string_list_clear(&revlist_args, 1);
 989
 990         if (finish_command(&exporter))
 991                 die("Error while running fast-export");
 992         if (push_update_refs_status(data, remote_refs, flags))
 993                 return 1;
 994
 995         if (data->export_marks) {
 996                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 997                 rename(buf.buf, data->export_marks);
 998                 strbuf_release(&buf);
 999         }
1000
1001         return 0;
1002 }
1003
1004 static int push_refs(struct transport *transport,
1005                 struct ref *remote_refs, int flags)
1006 {
1007         struct helper_data *data = transport->data;
1008
1009         if (process_connect(transport, 1)) {
1010                 do_take_over(transport);
1011                 return transport->vtable->push_refs(transport, remote_refs, flags);
1012         }
1013
1014         if (!remote_refs) {
1015                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
1016                         "Perhaps you should specify a branch such as 'master'.\n");
1017                 return 0;
1018         }
1019
1020         if (data->push)
1021                 return push_refs_with_push(transport, remote_refs, flags);
1022
1023         if (data->export)
1024                 return push_refs_with_export(transport, remote_refs, flags);
1025
1026         return -1;
1027 }
1028
1029
1030 static int has_attribute(const char *attrs, const char *attr) {
1031         int len;
1032         if (!attrs)
1033                 return 0;
1034
1035         len = strlen(attr);
1036         for (;;) {
1037                 const char *space = strchrnul(attrs, ' ');
1038                 if (len == space - attrs && !strncmp(attrs, attr, len))
1039                         return 1;
1040                 if (!*space)
1041                         return 0;
1042                 attrs = space + 1;
1043         }
1044 }
1045
1046 static struct ref *get_refs_list(struct transport *transport, int for_push,
1047                                  const struct argv_array *ref_prefixes)
1048 {
1049         struct helper_data *data = transport->data;
1050         struct child_process *helper;
1051         struct ref *ret = NULL;
1052         struct ref **tail = &ret;
1053         struct ref *posn;
1054         struct strbuf buf = STRBUF_INIT;
1055
1056         helper = get_helper(transport);
1057
1058         if (process_connect(transport, for_push)) {
1059                 do_take_over(transport);
1060                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1061         }
1062
1063         if (data->push && for_push)
1064                 write_str_in_full(helper->in, "list for-push\n");
1065         else
1066                 write_str_in_full(helper->in, "list\n");
1067
1068         while (1) {
1069                 char *eov, *eon;
1070                 if (recvline(data, &buf))
1071                         exit(128);
1072
1073                 if (!*buf.buf)
1074                         break;
1075
1076                 eov = strchr(buf.buf, ' ');
1077                 if (!eov)
1078                         die("Malformed response in ref list: %s", buf.buf);
1079                 eon = strchr(eov + 1, ' ');
1080                 *eov = '\0';
1081                 if (eon)
1082                         *eon = '\0';
1083                 *tail = alloc_ref(eov + 1);
1084                 if (buf.buf[0] == '@')
1085                         (*tail)->symref = xstrdup(buf.buf + 1);
1086                 else if (buf.buf[0] != '?')
1087                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1088                 if (eon) {
1089                         if (has_attribute(eon + 1, "unchanged")) {
1090                                 (*tail)->status |= REF_STATUS_UPTODATE;
1091                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1092                                         die(_("Could not read ref %s"),
1093                                             (*tail)->name);
1094                         }
1095                 }
1096                 tail = &((*tail)->next);
1097         }
1098         if (debug)
1099                 fprintf(stderr, "Debug: Read ref listing.\n");
1100         strbuf_release(&buf);
1101
1102         for (posn = ret; posn; posn = posn->next)
1103                 resolve_remote_symref(posn, ret);
1104
1105         return ret;
1106 }
1107
1108 static struct transport_vtable vtable = {
1109         set_helper_option,
1110         get_refs_list,
1111         fetch,
1112         push_refs,
1113         connect_helper,
1114         release_helper
1115 };
1116
1117 int transport_helper_init(struct transport *transport, const char *name)
1118 {
1119         struct helper_data *data = xcalloc(1, sizeof(*data));
1120         data->name = name;
1121
1122         transport_check_allowed(name);
1123
1124         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1125                 debug = 1;
1126
1127         transport->data = data;
1128         transport->vtable = &vtable;
1129         transport->smart_options = &(data->transport_options);
1130         return 0;
1131 }
1132
1133 /*
1134  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1135  * buffer less), so attempt reads and writes with up to that size.
1136  */
1137 #define BUFFERSIZE 65536
1138 /* This should be enough to hold debugging message. */
1139 #define PBUFFERSIZE 8192
1140
1141 /* Print bidirectional transfer loop debug message. */
1142 __attribute__((format (printf, 1, 2)))
1143 static void transfer_debug(const char *fmt, ...)
1144 {
1145         /*
1146          * NEEDSWORK: This function is sometimes used from multiple threads, and
1147          * we end up using debug_enabled racily. That "should not matter" since
1148          * we always write the same value, but it's still wrong. This function
1149          * is listed in .tsan-suppressions for the time being.
1150          */
1151
1152         va_list args;
1153         char msgbuf[PBUFFERSIZE];
1154         static int debug_enabled = -1;
1155
1156         if (debug_enabled < 0)
1157                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1158         if (!debug_enabled)
1159                 return;
1160
1161         va_start(args, fmt);
1162         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1163         va_end(args);
1164         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1165 }
1166
1167 /* Stream state: More data may be coming in this direction. */
1168 #define SSTATE_TRANSFERRING 0
1169 /*
1170  * Stream state: No more data coming in this direction, flushing rest of
1171  * data.
1172  */
1173 #define SSTATE_FLUSHING 1
1174 /* Stream state: Transfer in this direction finished. */
1175 #define SSTATE_FINISHED 2
1176
1177 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1178 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1179 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1180
1181 /* Unidirectional transfer. */
1182 struct unidirectional_transfer {
1183         /* Source */
1184         int src;
1185         /* Destination */
1186         int dest;
1187         /* Is source socket? */
1188         int src_is_sock;
1189         /* Is destination socket? */
1190         int dest_is_sock;
1191         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1192         int state;
1193         /* Buffer. */
1194         char buf[BUFFERSIZE];
1195         /* Buffer used. */
1196         size_t bufuse;
1197         /* Name of source. */
1198         const char *src_name;
1199         /* Name of destination. */
1200         const char *dest_name;
1201 };
1202
1203 /* Closes the target (for writing) if transfer has finished. */
1204 static void udt_close_if_finished(struct unidirectional_transfer *t)
1205 {
1206         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1207                 t->state = SSTATE_FINISHED;
1208                 if (t->dest_is_sock)
1209                         shutdown(t->dest, SHUT_WR);
1210                 else
1211                         close(t->dest);
1212                 transfer_debug("Closed %s.", t->dest_name);
1213         }
1214 }
1215
1216 /*
1217  * Tries to read data from source into buffer. If buffer is full,
1218  * no data is read. Returns 0 on success, -1 on error.
1219  */
1220 static int udt_do_read(struct unidirectional_transfer *t)
1221 {
1222         ssize_t bytes;
1223
1224         if (t->bufuse == BUFFERSIZE)
1225                 return 0;       /* No space for more. */
1226
1227         transfer_debug("%s is readable", t->src_name);
1228         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1229         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1230                 errno != EINTR) {
1231                 error_errno("read(%s) failed", t->src_name);
1232                 return -1;
1233         } else if (bytes == 0) {
1234                 transfer_debug("%s EOF (with %i bytes in buffer)",
1235                         t->src_name, (int)t->bufuse);
1236                 t->state = SSTATE_FLUSHING;
1237         } else if (bytes > 0) {
1238                 t->bufuse += bytes;
1239                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1240                         (int)bytes, t->src_name, (int)t->bufuse);
1241         }
1242         return 0;
1243 }
1244
1245 /* Tries to write data from buffer into destination. If buffer is empty,
1246  * no data is written. Returns 0 on success, -1 on error.
1247  */
1248 static int udt_do_write(struct unidirectional_transfer *t)
1249 {
1250         ssize_t bytes;
1251
1252         if (t->bufuse == 0)
1253                 return 0;       /* Nothing to write. */
1254
1255         transfer_debug("%s is writable", t->dest_name);
1256         bytes = xwrite(t->dest, t->buf, t->bufuse);
1257         if (bytes < 0 && errno != EWOULDBLOCK) {
1258                 error_errno("write(%s) failed", t->dest_name);
1259                 return -1;
1260         } else if (bytes > 0) {
1261                 t->bufuse -= bytes;
1262                 if (t->bufuse)
1263                         memmove(t->buf, t->buf + bytes, t->bufuse);
1264                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1265                         (int)bytes, t->dest_name, (int)t->bufuse);
1266         }
1267         return 0;
1268 }
1269
1270
1271 /* State of bidirectional transfer loop. */
1272 struct bidirectional_transfer_state {
1273         /* Direction from program to git. */
1274         struct unidirectional_transfer ptg;
1275         /* Direction from git to program. */
1276         struct unidirectional_transfer gtp;
1277 };
1278
1279 static void *udt_copy_task_routine(void *udt)
1280 {
1281         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1282         while (t->state != SSTATE_FINISHED) {
1283                 if (STATE_NEEDS_READING(t->state))
1284                         if (udt_do_read(t))
1285                                 return NULL;
1286                 if (STATE_NEEDS_WRITING(t->state))
1287                         if (udt_do_write(t))
1288                                 return NULL;
1289                 if (STATE_NEEDS_CLOSING(t->state))
1290                         udt_close_if_finished(t);
1291         }
1292         return udt;     /* Just some non-NULL value. */
1293 }
1294
1295 #ifndef NO_PTHREADS
1296
1297 /*
1298  * Join thread, with appropriate errors on failure. Name is name for the
1299  * thread (for error messages). Returns 0 on success, 1 on failure.
1300  */
1301 static int tloop_join(pthread_t thread, const char *name)
1302 {
1303         int err;
1304         void *tret;
1305         err = pthread_join(thread, &tret);
1306         if (!tret) {
1307                 error("%s thread failed", name);
1308                 return 1;
1309         }
1310         if (err) {
1311                 error("%s thread failed to join: %s", name, strerror(err));
1312                 return 1;
1313         }
1314         return 0;
1315 }
1316
1317 /*
1318  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1319  * -1 on failure.
1320  */
1321 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1322 {
1323         pthread_t gtp_thread;
1324         pthread_t ptg_thread;
1325         int err;
1326         int ret = 0;
1327         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1328                 &s->gtp);
1329         if (err)
1330                 die("Can't start thread for copying data: %s", strerror(err));
1331         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1332                 &s->ptg);
1333         if (err)
1334                 die("Can't start thread for copying data: %s", strerror(err));
1335
1336         ret |= tloop_join(gtp_thread, "Git to program copy");
1337         ret |= tloop_join(ptg_thread, "Program to git copy");
1338         return ret;
1339 }
1340 #else
1341
1342 /* Close the source and target (for writing) for transfer. */
1343 static void udt_kill_transfer(struct unidirectional_transfer *t)
1344 {
1345         t->state = SSTATE_FINISHED;
1346         /*
1347          * Socket read end left open isn't a disaster if nobody
1348          * attempts to read from it (mingw compat headers do not
1349          * have SHUT_RD)...
1350          *
1351          * We can't fully close the socket since otherwise gtp
1352          * task would first close the socket it sends data to
1353          * while closing the ptg file descriptors.
1354          */
1355         if (!t->src_is_sock)
1356                 close(t->src);
1357         if (t->dest_is_sock)
1358                 shutdown(t->dest, SHUT_WR);
1359         else
1360                 close(t->dest);
1361 }
1362
1363 /*
1364  * Join process, with appropriate errors on failure. Name is name for the
1365  * process (for error messages). Returns 0 on success, 1 on failure.
1366  */
1367 static int tloop_join(pid_t pid, const char *name)
1368 {
1369         int tret;
1370         if (waitpid(pid, &tret, 0) < 0) {
1371                 error_errno("%s process failed to wait", name);
1372                 return 1;
1373         }
1374         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1375                 error("%s process failed", name);
1376                 return 1;
1377         }
1378         return 0;
1379 }
1380
1381 /*
1382  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1383  * -1 on failure.
1384  */
1385 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1386 {
1387         pid_t pid1, pid2;
1388         int ret = 0;
1389
1390         /* Fork thread #1: git to program. */
1391         pid1 = fork();
1392         if (pid1 < 0)
1393                 die_errno("Can't start thread for copying data");
1394         else if (pid1 == 0) {
1395                 udt_kill_transfer(&s->ptg);
1396                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1397         }
1398
1399         /* Fork thread #2: program to git. */
1400         pid2 = fork();
1401         if (pid2 < 0)
1402                 die_errno("Can't start thread for copying data");
1403         else if (pid2 == 0) {
1404                 udt_kill_transfer(&s->gtp);
1405                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1406         }
1407
1408         /*
1409          * Close both streams in parent as to not interfere with
1410          * end of file detection and wait for both tasks to finish.
1411          */
1412         udt_kill_transfer(&s->gtp);
1413         udt_kill_transfer(&s->ptg);
1414         ret |= tloop_join(pid1, "Git to program copy");
1415         ret |= tloop_join(pid2, "Program to git copy");
1416         return ret;
1417 }
1418 #endif
1419
1420 /*
1421  * Copies data from stdin to output and from input to stdout simultaneously.
1422  * Additionally filtering through given filter. If filter is NULL, uses
1423  * identity filter.
1424  */
1425 int bidirectional_transfer_loop(int input, int output)
1426 {
1427         struct bidirectional_transfer_state state;
1428
1429         /* Fill the state fields. */
1430         state.ptg.src = input;
1431         state.ptg.dest = 1;
1432         state.ptg.src_is_sock = (input == output);
1433         state.ptg.dest_is_sock = 0;
1434         state.ptg.state = SSTATE_TRANSFERRING;
1435         state.ptg.bufuse = 0;
1436         state.ptg.src_name = "remote input";
1437         state.ptg.dest_name = "stdout";
1438
1439         state.gtp.src = 0;
1440         state.gtp.dest = output;
1441         state.gtp.src_is_sock = 0;
1442         state.gtp.dest_is_sock = (input == output);
1443         state.gtp.state = SSTATE_TRANSFERRING;
1444         state.gtp.bufuse = 0;
1445         state.gtp.src_name = "stdin";
1446         state.gtp.dest_name = "remote output";
1447
1448         return tloop_spawnwait_tasks(&state);
1449 }