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         helper->trace2_child_class = helper->args.argv[0]; /* "remote-<name>" */
 131
 132         code = start_command(helper);
 133         if (code < 0 && errno == ENOENT)
 134                 die(_("unable to find remote helper for '%s'"), data->name);
 135         else if (code != 0)
 136                 exit(code);
 137
 138         data->helper = helper;
 139         data->no_disconnect_req = 0;
 140         refspec_init(&data->rs, REFSPEC_FETCH);
 141
 142         /*
 143          * Open the output as FILE* so strbuf_getline_*() family of
 144          * functions can be used.
 145          * Do this with duped fd because fclose() will close the fd,
 146          * and stuff like taking over will require the fd to remain.
 147          */
 148         duped = dup(helper->out);
 149         if (duped < 0)
 150                 die_errno(_("can't dup helper output fd"));
 151         data->out = xfdopen(duped, "r");
 152
 153         write_constant(helper->in, "capabilities\n");
 154
 155         while (1) {
 156                 const char *capname, *arg;
 157                 int mandatory = 0;
 158                 if (recvline(data, &buf))
 159                         exit(128);
 160
 161                 if (!*buf.buf)
 162                         break;
 163
 164                 if (*buf.buf == '*') {
 165                         capname = buf.buf + 1;
 166                         mandatory = 1;
 167                 } else
 168                         capname = buf.buf;
 169
 170                 if (debug)
 171                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 172                 if (!strcmp(capname, "fetch"))
 173                         data->fetch = 1;
 174                 else if (!strcmp(capname, "option"))
 175                         data->option = 1;
 176                 else if (!strcmp(capname, "push"))
 177                         data->push = 1;
 178                 else if (!strcmp(capname, "import"))
 179                         data->import = 1;
 180                 else if (!strcmp(capname, "bidi-import"))
 181                         data->bidi_import = 1;
 182                 else if (!strcmp(capname, "export"))
 183                         data->export = 1;
 184                 else if (!strcmp(capname, "check-connectivity"))
 185                         data->check_connectivity = 1;
 186                 else if (skip_prefix(capname, "refspec ", &arg)) {
 187                         refspec_append(&data->rs, arg);
 188                 } else if (!strcmp(capname, "connect")) {
 189                         data->connect = 1;
 190                 } else if (!strcmp(capname, "stateless-connect")) {
 191                         data->stateless_connect = 1;
 192                 } else if (!strcmp(capname, "signed-tags")) {
 193                         data->signed_tags = 1;
 194                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 195                         data->export_marks = xstrdup(arg);
 196                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 197                         data->import_marks = xstrdup(arg);
 198                 } else if (starts_with(capname, "no-private-update")) {
 199                         data->no_private_update = 1;
 200                 } else if (mandatory) {
 201                         die(_("unknown mandatory capability %s; this remote "
 202                               "helper probably needs newer version of Git"),
 203                             capname);
 204                 }
 205         }
 206         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
 207                 warning(_("this remote helper should implement refspec capability"));
 208         }
 209         strbuf_release(&buf);
 210         if (debug)
 211                 fprintf(stderr, "Debug: Capabilities complete.\n");
 212         standard_options(transport);
 213         return data->helper;
 214 }
 215
 216 static int disconnect_helper(struct transport *transport)
 217 {
 218         struct helper_data *data = transport->data;
 219         int res = 0;
 220
 221         if (data->helper) {
 222                 if (debug)
 223                         fprintf(stderr, "Debug: Disconnecting.\n");
 224                 if (!data->no_disconnect_req) {
 225                         /*
 226                          * Ignore write errors; there's nothing we can do,
 227                          * since we're about to close the pipe anyway. And the
 228                          * most likely error is EPIPE due to the helper dying
 229                          * to report an error itself.
 230                          */
 231                         sigchain_push(SIGPIPE, SIG_IGN);
 232                         xwrite(data->helper->in, "\n", 1);
 233                         sigchain_pop(SIGPIPE);
 234                 }
 235                 close(data->helper->in);
 236                 close(data->helper->out);
 237                 fclose(data->out);
 238                 res = finish_command(data->helper);
 239                 FREE_AND_NULL(data->helper);
 240         }
 241         return res;
 242 }
 243
 244 static const char *unsupported_options[] = {
 245         TRANS_OPT_UPLOADPACK,
 246         TRANS_OPT_RECEIVEPACK,
 247         TRANS_OPT_THIN,
 248         TRANS_OPT_KEEP
 249         };
 250
 251 static const char *boolean_options[] = {
 252         TRANS_OPT_THIN,
 253         TRANS_OPT_KEEP,
 254         TRANS_OPT_FOLLOWTAGS,
 255         TRANS_OPT_DEEPEN_RELATIVE
 256         };
 257
 258 static int strbuf_set_helper_option(struct helper_data *data,
 259                                     struct strbuf *buf)
 260 {
 261         int ret;
 262
 263         sendline(data, buf);
 264         if (recvline(data, buf))
 265                 exit(128);
 266
 267         if (!strcmp(buf->buf, "ok"))
 268                 ret = 0;
 269         else if (starts_with(buf->buf, "error"))
 270                 ret = -1;
 271         else if (!strcmp(buf->buf, "unsupported"))
 272                 ret = 1;
 273         else {
 274                 warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
 275                 ret = 1;
 276         }
 277         return ret;
 278 }
 279
 280 static int string_list_set_helper_option(struct helper_data *data,
 281                                          const char *name,
 282                                          struct string_list *list)
 283 {
 284         struct strbuf buf = STRBUF_INIT;
 285         int i, ret = 0;
 286
 287         for (i = 0; i < list->nr; i++) {
 288                 strbuf_addf(&buf, "option %s ", name);
 289                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 290                 strbuf_addch(&buf, '\n');
 291
 292                 if ((ret = strbuf_set_helper_option(data, &buf)))
 293                         break;
 294                 strbuf_reset(&buf);
 295         }
 296         strbuf_release(&buf);
 297         return ret;
 298 }
 299
 300 static int set_helper_option(struct transport *transport,
 301                           const char *name, const char *value)
 302 {
 303         struct helper_data *data = transport->data;
 304         struct strbuf buf = STRBUF_INIT;
 305         int i, ret, is_bool = 0;
 306
 307         get_helper(transport);
 308
 309         if (!data->option)
 310                 return 1;
 311
 312         if (!strcmp(name, "deepen-not"))
 313                 return string_list_set_helper_option(data, name,
 314                                                      (struct string_list *)value);
 315
 316         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 317                 if (!strcmp(name, unsupported_options[i]))
 318                         return 1;
 319         }
 320
 321         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 322                 if (!strcmp(name, boolean_options[i])) {
 323                         is_bool = 1;
 324                         break;
 325                 }
 326         }
 327
 328         strbuf_addf(&buf, "option %s ", name);
 329         if (is_bool)
 330                 strbuf_addstr(&buf, value ? "true" : "false");
 331         else
 332                 quote_c_style(value, &buf, NULL, 0);
 333         strbuf_addch(&buf, '\n');
 334
 335         ret = strbuf_set_helper_option(data, &buf);
 336         strbuf_release(&buf);
 337         return ret;
 338 }
 339
 340 static void standard_options(struct transport *t)
 341 {
 342         char buf[16];
 343         int v = t->verbose;
 344
 345         set_helper_option(t, "progress", t->progress ? "true" : "false");
 346
 347         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 348         set_helper_option(t, "verbosity", buf);
 349
 350         switch (t->family) {
 351         case TRANSPORT_FAMILY_ALL:
 352                 /*
 353                  * this is already the default,
 354                  * do not break old remote helpers by setting "all" here
 355                  */
 356                 break;
 357         case TRANSPORT_FAMILY_IPV4:
 358                 set_helper_option(t, "family", "ipv4");
 359                 break;
 360         case TRANSPORT_FAMILY_IPV6:
 361                 set_helper_option(t, "family", "ipv6");
 362                 break;
 363         }
 364 }
 365
 366 static int release_helper(struct transport *transport)
 367 {
 368         int res = 0;
 369         struct helper_data *data = transport->data;
 370         refspec_clear(&data->rs);
 371         res = disconnect_helper(transport);
 372         free(transport->data);
 373         return res;
 374 }
 375
 376 static int fetch_with_fetch(struct transport *transport,
 377                             int nr_heads, struct ref **to_fetch)
 378 {
 379         struct helper_data *data = transport->data;
 380         int i;
 381         struct strbuf buf = STRBUF_INIT;
 382
 383         for (i = 0; i < nr_heads; i++) {
 384                 const struct ref *posn = to_fetch[i];
 385                 if (posn->status & REF_STATUS_UPTODATE)
 386                         continue;
 387
 388                 strbuf_addf(&buf, "fetch %s %s\n",
 389                             oid_to_hex(&posn->old_oid),
 390                             posn->symref ? posn->symref : posn->name);
 391         }
 392
 393         strbuf_addch(&buf, '\n');
 394         sendline(data, &buf);
 395
 396         while (1) {
 397                 if (recvline(data, &buf))
 398                         exit(128);
 399
 400                 if (starts_with(buf.buf, "lock ")) {
 401                         const char *name = buf.buf + 5;
 402                         if (transport->pack_lockfile)
 403                                 warning(_("%s also locked %s"), data->name, name);
 404                         else
 405                                 transport->pack_lockfile = xstrdup(name);
 406                 }
 407                 else if (data->check_connectivity &&
 408                          data->transport_options.check_self_contained_and_connected &&
 409                          !strcmp(buf.buf, "connectivity-ok"))
 410                         data->transport_options.self_contained_and_connected = 1;
 411                 else if (!buf.len)
 412                         break;
 413                 else
 414                         warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
 415         }
 416         strbuf_release(&buf);
 417         return 0;
 418 }
 419
 420 static int get_importer(struct transport *transport, struct child_process *fastimport)
 421 {
 422         struct child_process *helper = get_helper(transport);
 423         struct helper_data *data = transport->data;
 424         int cat_blob_fd, code;
 425         child_process_init(fastimport);
 426         fastimport->in = xdup(helper->out);
 427         argv_array_push(&fastimport->args, "fast-import");
 428         argv_array_push(&fastimport->args, "--allow-unsafe-features");
 429         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 430
 431         if (data->bidi_import) {
 432                 cat_blob_fd = xdup(helper->in);
 433                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 434         }
 435         fastimport->git_cmd = 1;
 436
 437         code = start_command(fastimport);
 438         return code;
 439 }
 440
 441 static int get_exporter(struct transport *transport,
 442                         struct child_process *fastexport,
 443                         struct string_list *revlist_args)
 444 {
 445         struct helper_data *data = transport->data;
 446         struct child_process *helper = get_helper(transport);
 447         int i;
 448
 449         child_process_init(fastexport);
 450
 451         /* we need to duplicate helper->in because we want to use it after
 452          * fastexport is done with it. */
 453         fastexport->out = dup(helper->in);
 454         argv_array_push(&fastexport->args, "fast-export");
 455         argv_array_push(&fastexport->args, "--use-done-feature");
 456         argv_array_push(&fastexport->args, data->signed_tags ?
 457                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 458         if (data->export_marks)
 459                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 460         if (data->import_marks)
 461                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 462
 463         for (i = 0; i < revlist_args->nr; i++)
 464                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 465
 466         fastexport->git_cmd = 1;
 467         return start_command(fastexport);
 468 }
 469
 470 static int fetch_with_import(struct transport *transport,
 471                              int nr_heads, struct ref **to_fetch)
 472 {
 473         struct child_process fastimport;
 474         struct helper_data *data = transport->data;
 475         int i;
 476         struct ref *posn;
 477         struct strbuf buf = STRBUF_INIT;
 478
 479         get_helper(transport);
 480
 481         if (get_importer(transport, &fastimport))
 482                 die(_("couldn't run fast-import"));
 483
 484         for (i = 0; i < nr_heads; i++) {
 485                 posn = to_fetch[i];
 486                 if (posn->status & REF_STATUS_UPTODATE)
 487                         continue;
 488
 489                 strbuf_addf(&buf, "import %s\n",
 490                             posn->symref ? posn->symref : posn->name);
 491                 sendline(data, &buf);
 492                 strbuf_reset(&buf);
 493         }
 494
 495         write_constant(data->helper->in, "\n");
 496         /*
 497          * remote-helpers that advertise the bidi-import capability are required to
 498          * buffer the complete batch of import commands until this newline before
 499          * sending data to fast-import.
 500          * These helpers read back data from fast-import on their stdin, which could
 501          * be mixed with import commands, otherwise.
 502          */
 503
 504         if (finish_command(&fastimport))
 505                 die(_("error while running fast-import"));
 506
 507         /*
 508          * The fast-import stream of a remote helper that advertises
 509          * the "refspec" capability writes to the refs named after the
 510          * right hand side of the first refspec matching each ref we
 511          * were fetching.
 512          *
 513          * (If no "refspec" capability was specified, for historical
 514          * reasons we default to the equivalent of *:*.)
 515          *
 516          * Store the result in to_fetch[i].old_sha1.  Callers such
 517          * as "git fetch" can use the value to write feedback to the
 518          * terminal, populate FETCH_HEAD, and determine what new value
 519          * should be written to peer_ref if the update is a
 520          * fast-forward or this is a forced update.
 521          */
 522         for (i = 0; i < nr_heads; i++) {
 523                 char *private, *name;
 524                 posn = to_fetch[i];
 525                 if (posn->status & REF_STATUS_UPTODATE)
 526                         continue;
 527                 name = posn->symref ? posn->symref : posn->name;
 528                 if (data->rs.nr)
 529                         private = apply_refspecs(&data->rs, name);
 530                 else
 531                         private = xstrdup(name);
 532                 if (private) {
 533                         if (read_ref(private, &posn->old_oid) < 0)
 534                                 die(_("could not read ref %s"), private);
 535                         free(private);
 536                 }
 537         }
 538         strbuf_release(&buf);
 539         return 0;
 540 }
 541
 542 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 543 {
 544         struct helper_data *data = transport->data;
 545         int ret = 0;
 546         int duped;
 547         FILE *input;
 548         struct child_process *helper;
 549
 550         helper = get_helper(transport);
 551
 552         /*
 553          * Yes, dup the pipe another time, as we need unbuffered version
 554          * of input pipe as FILE*. fclose() closes the underlying fd and
 555          * stream buffering only can be changed before first I/O operation
 556          * on it.
 557          */
 558         duped = dup(helper->out);
 559         if (duped < 0)
 560                 die_errno(_("can't dup helper output fd"));
 561         input = xfdopen(duped, "r");
 562         setvbuf(input, NULL, _IONBF, 0);
 563
 564         sendline(data, cmdbuf);
 565         if (recvline_fh(input, cmdbuf))
 566                 exit(128);
 567
 568         if (!strcmp(cmdbuf->buf, "")) {
 569                 data->no_disconnect_req = 1;
 570                 if (debug)
 571                         fprintf(stderr, "Debug: Smart transport connection "
 572                                 "ready.\n");
 573                 ret = 1;
 574         } else if (!strcmp(cmdbuf->buf, "fallback")) {
 575                 if (debug)
 576                         fprintf(stderr, "Debug: Falling back to dumb "
 577                                 "transport.\n");
 578         } else {
 579                 die(_("unknown response to connect: %s"),
 580                     cmdbuf->buf);
 581         }
 582
 583         fclose(input);
 584         return ret;
 585 }
 586
 587 static int process_connect_service(struct transport *transport,
 588                                    const char *name, const char *exec)
 589 {
 590         struct helper_data *data = transport->data;
 591         struct strbuf cmdbuf = STRBUF_INIT;
 592         int ret = 0;
 593
 594         /*
 595          * Handle --upload-pack and friends. This is fire and forget...
 596          * just warn if it fails.
 597          */
 598         if (strcmp(name, exec)) {
 599                 int r = set_helper_option(transport, "servpath", exec);
 600                 if (r > 0)
 601                         warning(_("setting remote service path not supported by protocol"));
 602                 else if (r < 0)
 603                         warning(_("invalid remote service path"));
 604         }
 605
 606         if (data->connect) {
 607                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 608                 ret = run_connect(transport, &cmdbuf);
 609         } else if (data->stateless_connect &&
 610                    (get_protocol_version_config() == protocol_v2) &&
 611                    !strcmp("git-upload-pack", name)) {
 612                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 613                 ret = run_connect(transport, &cmdbuf);
 614                 if (ret)
 615                         transport->stateless_rpc = 1;
 616         }
 617
 618         strbuf_release(&cmdbuf);
 619         return ret;
 620 }
 621
 622 static int process_connect(struct transport *transport,
 623                                      int for_push)
 624 {
 625         struct helper_data *data = transport->data;
 626         const char *name;
 627         const char *exec;
 628
 629         name = for_push ? "git-receive-pack" : "git-upload-pack";
 630         if (for_push)
 631                 exec = data->transport_options.receivepack;
 632         else
 633                 exec = data->transport_options.uploadpack;
 634
 635         return process_connect_service(transport, name, exec);
 636 }
 637
 638 static int connect_helper(struct transport *transport, const char *name,
 639                    const char *exec, int fd[2])
 640 {
 641         struct helper_data *data = transport->data;
 642
 643         /* Get_helper so connect is inited. */
 644         get_helper(transport);
 645         if (!data->connect)
 646                 die(_("operation not supported by protocol"));
 647
 648         if (!process_connect_service(transport, name, exec))
 649                 die(_("can't connect to subservice %s"), name);
 650
 651         fd[0] = data->helper->out;
 652         fd[1] = data->helper->in;
 653         return 0;
 654 }
 655
 656 static int fetch(struct transport *transport,
 657                  int nr_heads, struct ref **to_fetch)
 658 {
 659         struct helper_data *data = transport->data;
 660         int i, count;
 661
 662         if (process_connect(transport, 0)) {
 663                 do_take_over(transport);
 664                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
 665         }
 666
 667         count = 0;
 668         for (i = 0; i < nr_heads; i++)
 669                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 670                         count++;
 671
 672         if (!count)
 673                 return 0;
 674
 675         if (data->check_connectivity &&
 676             data->transport_options.check_self_contained_and_connected)
 677                 set_helper_option(transport, "check-connectivity", "true");
 678
 679         if (transport->cloning)
 680                 set_helper_option(transport, "cloning", "true");
 681
 682         if (data->transport_options.update_shallow)
 683                 set_helper_option(transport, "update-shallow", "true");
 684
 685         if (data->transport_options.filter_options.choice) {
 686                 struct strbuf expanded_filter_spec = STRBUF_INIT;
 687                 expand_list_objects_filter_spec(
 688                         &data->transport_options.filter_options,
 689                         &expanded_filter_spec);
 690                 set_helper_option(transport, "filter",
 691                                   expanded_filter_spec.buf);
 692                 strbuf_release(&expanded_filter_spec);
 693         }
 694
 695         if (data->transport_options.negotiation_tips)
 696                 warning("Ignoring --negotiation-tip because the protocol does not support it.");
 697
 698         if (data->fetch)
 699                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 700
 701         if (data->import)
 702                 return fetch_with_import(transport, nr_heads, to_fetch);
 703
 704         return -1;
 705 }
 706
 707 static int push_update_ref_status(struct strbuf *buf,
 708                                    struct ref **ref,
 709                                    struct ref *remote_refs)
 710 {
 711         char *refname, *msg;
 712         int status, forced = 0;
 713
 714         if (starts_with(buf->buf, "ok ")) {
 715                 status = REF_STATUS_OK;
 716                 refname = buf->buf + 3;
 717         } else if (starts_with(buf->buf, "error ")) {
 718                 status = REF_STATUS_REMOTE_REJECT;
 719                 refname = buf->buf + 6;
 720         } else
 721                 die(_("expected ok/error, helper said '%s'"), buf->buf);
 722
 723         msg = strchr(refname, ' ');
 724         if (msg) {
 725                 struct strbuf msg_buf = STRBUF_INIT;
 726                 const char *end;
 727
 728                 *msg++ = '\0';
 729                 if (!unquote_c_style(&msg_buf, msg, &end))
 730                         msg = strbuf_detach(&msg_buf, NULL);
 731                 else
 732                         msg = xstrdup(msg);
 733                 strbuf_release(&msg_buf);
 734
 735                 if (!strcmp(msg, "no match")) {
 736                         status = REF_STATUS_NONE;
 737                         FREE_AND_NULL(msg);
 738                 }
 739                 else if (!strcmp(msg, "up to date")) {
 740                         status = REF_STATUS_UPTODATE;
 741                         FREE_AND_NULL(msg);
 742                 }
 743                 else if (!strcmp(msg, "non-fast forward")) {
 744                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 745                         FREE_AND_NULL(msg);
 746                 }
 747                 else if (!strcmp(msg, "already exists")) {
 748                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 749                         FREE_AND_NULL(msg);
 750                 }
 751                 else if (!strcmp(msg, "fetch first")) {
 752                         status = REF_STATUS_REJECT_FETCH_FIRST;
 753                         FREE_AND_NULL(msg);
 754                 }
 755                 else if (!strcmp(msg, "needs force")) {
 756                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 757                         FREE_AND_NULL(msg);
 758                 }
 759                 else if (!strcmp(msg, "stale info")) {
 760                         status = REF_STATUS_REJECT_STALE;
 761                         FREE_AND_NULL(msg);
 762                 }
 763                 else if (!strcmp(msg, "forced update")) {
 764                         forced = 1;
 765                         FREE_AND_NULL(msg);
 766                 }
 767         }
 768
 769         if (*ref)
 770                 *ref = find_ref_by_name(*ref, refname);
 771         if (!*ref)
 772                 *ref = find_ref_by_name(remote_refs, refname);
 773         if (!*ref) {
 774                 warning(_("helper reported unexpected status of %s"), refname);
 775                 return 1;
 776         }
 777
 778         if ((*ref)->status != REF_STATUS_NONE) {
 779                 /*
 780                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 781                  * status reported by the remote helper if the latter is 'no match'.
 782                  */
 783                 if (status == REF_STATUS_NONE)
 784                         return 1;
 785         }
 786
 787         (*ref)->status = status;
 788         (*ref)->forced_update |= forced;
 789         (*ref)->remote_status = msg;
 790         return !(status == REF_STATUS_OK);
 791 }
 792
 793 static int push_update_refs_status(struct helper_data *data,
 794                                     struct ref *remote_refs,
 795                                     int flags)
 796 {
 797         struct strbuf buf = STRBUF_INIT;
 798         struct ref *ref = remote_refs;
 799         int ret = 0;
 800
 801         for (;;) {
 802                 char *private;
 803
 804                 if (recvline(data, &buf)) {
 805                         ret = 1;
 806                         break;
 807                 }
 808
 809                 if (!buf.len)
 810                         break;
 811
 812                 if (push_update_ref_status(&buf, &ref, remote_refs))
 813                         continue;
 814
 815                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
 816                         continue;
 817
 818                 /* propagate back the update to the remote namespace */
 819                 private = apply_refspecs(&data->rs, ref->name);
 820                 if (!private)
 821                         continue;
 822                 update_ref("update by helper", private, &ref->new_oid, NULL,
 823                            0, 0);
 824                 free(private);
 825         }
 826         strbuf_release(&buf);
 827         return ret;
 828 }
 829
 830 static void set_common_push_options(struct transport *transport,
 831                                    const char *name, int flags)
 832 {
 833         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 834                 if (set_helper_option(transport, "dry-run", "true") != 0)
 835                         die(_("helper %s does not support dry-run"), name);
 836         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 837                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 838                         die(_("helper %s does not support --signed"), name);
 839         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 840                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 841                         die(_("helper %s does not support --signed=if-asked"), name);
 842         }
 843
 844         if (flags & TRANSPORT_PUSH_OPTIONS) {
 845                 struct string_list_item *item;
 846                 for_each_string_list_item(item, transport->push_options)
 847                         if (set_helper_option(transport, "push-option", item->string) != 0)
 848                                 die(_("helper %s does not support 'push-option'"), name);
 849         }
 850 }
 851
 852 static int push_refs_with_push(struct transport *transport,
 853                                struct ref *remote_refs, int flags)
 854 {
 855         int force_all = flags & TRANSPORT_PUSH_FORCE;
 856         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 857         int atomic = flags & TRANSPORT_PUSH_ATOMIC;
 858         struct helper_data *data = transport->data;
 859         struct strbuf buf = STRBUF_INIT;
 860         struct ref *ref;
 861         struct string_list cas_options = STRING_LIST_INIT_DUP;
 862         struct string_list_item *cas_option;
 863
 864         get_helper(transport);
 865         if (!data->push)
 866                 return 1;
 867
 868         for (ref = remote_refs; ref; ref = ref->next) {
 869                 if (!ref->peer_ref && !mirror)
 870                         continue;
 871
 872                 /* Check for statuses set by set_ref_status_for_push() */
 873                 switch (ref->status) {
 874                 case REF_STATUS_REJECT_NONFASTFORWARD:
 875                 case REF_STATUS_REJECT_STALE:
 876                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 877                         if (atomic) {
 878                                 string_list_clear(&cas_options, 0);
 879                                 return 0;
 880                         } else
 881                                 continue;
 882                 case REF_STATUS_UPTODATE:
 883                         continue;
 884                 default:
 885                         ; /* do nothing */
 886                 }
 887
 888                 if (force_all)
 889                         ref->force = 1;
 890
 891                 strbuf_addstr(&buf, "push ");
 892                 if (!ref->deletion) {
 893                         if (ref->force)
 894                                 strbuf_addch(&buf, '+');
 895                         if (ref->peer_ref)
 896                                 strbuf_addstr(&buf, ref->peer_ref->name);
 897                         else
 898                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 899                 }
 900                 strbuf_addch(&buf, ':');
 901                 strbuf_addstr(&buf, ref->name);
 902                 strbuf_addch(&buf, '\n');
 903
 904                 /*
 905                  * The "--force-with-lease" options without explicit
 906                  * values to expect have already been expanded into
 907                  * the ref->old_oid_expect[] field; we can ignore
 908                  * transport->smart_options->cas altogether and instead
 909                  * can enumerate them from the refs.
 910                  */
 911                 if (ref->expect_old_sha1) {
 912                         struct strbuf cas = STRBUF_INIT;
 913                         strbuf_addf(&cas, "%s:%s",
 914                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 915                         string_list_append_nodup(&cas_options,
 916                                                  strbuf_detach(&cas, NULL));
 917                 }
 918         }
 919         if (buf.len == 0) {
 920                 string_list_clear(&cas_options, 0);
 921                 return 0;
 922         }
 923
 924         for_each_string_list_item(cas_option, &cas_options)
 925                 set_helper_option(transport, "cas", cas_option->string);
 926         set_common_push_options(transport, data->name, flags);
 927
 928         strbuf_addch(&buf, '\n');
 929         sendline(data, &buf);
 930         strbuf_release(&buf);
 931         string_list_clear(&cas_options, 0);
 932
 933         return push_update_refs_status(data, remote_refs, flags);
 934 }
 935
 936 static int push_refs_with_export(struct transport *transport,
 937                 struct ref *remote_refs, int flags)
 938 {
 939         struct ref *ref;
 940         struct child_process *helper, exporter;
 941         struct helper_data *data = transport->data;
 942         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 943         struct strbuf buf = STRBUF_INIT;
 944
 945         if (!data->rs.nr)
 946                 die(_("remote-helper doesn't support push; refspec needed"));
 947
 948         set_common_push_options(transport, data->name, flags);
 949         if (flags & TRANSPORT_PUSH_FORCE) {
 950                 if (set_helper_option(transport, "force", "true") != 0)
 951                         warning(_("helper %s does not support 'force'"), data->name);
 952         }
 953
 954         helper = get_helper(transport);
 955
 956         write_constant(helper->in, "export\n");
 957
 958         for (ref = remote_refs; ref; ref = ref->next) {
 959                 char *private;
 960                 struct object_id oid;
 961
 962                 private = apply_refspecs(&data->rs, ref->name);
 963                 if (private && !get_oid(private, &oid)) {
 964                         strbuf_addf(&buf, "^%s", private);
 965                         string_list_append_nodup(&revlist_args,
 966                                                  strbuf_detach(&buf, NULL));
 967                         oidcpy(&ref->old_oid, &oid);
 968                 }
 969                 free(private);
 970
 971                 if (ref->peer_ref) {
 972                         if (strcmp(ref->name, ref->peer_ref->name)) {
 973                                 if (!ref->deletion) {
 974                                         const char *name;
 975                                         int flag;
 976
 977                                         /* Follow symbolic refs (mainly for HEAD). */
 978                                         name = resolve_ref_unsafe(ref->peer_ref->name,
 979                                                                   RESOLVE_REF_READING,
 980                                                                   &oid, &flag);
 981                                         if (!name || !(flag & REF_ISSYMREF))
 982                                                 name = ref->peer_ref->name;
 983
 984                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 985                                 } else
 986                                         strbuf_addf(&buf, ":%s", ref->name);
 987
 988                                 string_list_append(&revlist_args, "--refspec");
 989                                 string_list_append(&revlist_args, buf.buf);
 990                                 strbuf_release(&buf);
 991                         }
 992                         if (!ref->deletion)
 993                                 string_list_append(&revlist_args, ref->peer_ref->name);
 994                 }
 995         }
 996
 997         if (get_exporter(transport, &exporter, &revlist_args))
 998                 die(_("couldn't run fast-export"));
 999
1000         string_list_clear(&revlist_args, 1);
1001
1002         if (finish_command(&exporter))
1003                 die(_("error while running fast-export"));
1004         if (push_update_refs_status(data, remote_refs, flags))
1005                 return 1;
1006
1007         if (data->export_marks) {
1008                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
1009                 rename(buf.buf, data->export_marks);
1010                 strbuf_release(&buf);
1011         }
1012
1013         return 0;
1014 }
1015
1016 static int push_refs(struct transport *transport,
1017                 struct ref *remote_refs, int flags)
1018 {
1019         struct helper_data *data = transport->data;
1020
1021         if (process_connect(transport, 1)) {
1022                 do_take_over(transport);
1023                 return transport->vtable->push_refs(transport, remote_refs, flags);
1024         }
1025
1026         if (!remote_refs) {
1027                 fprintf(stderr,
1028                         _("No refs in common and none specified; doing nothing.\n"
1029                           "Perhaps you should specify a branch such as 'master'.\n"));
1030                 return 0;
1031         }
1032
1033         if (data->push)
1034                 return push_refs_with_push(transport, remote_refs, flags);
1035
1036         if (data->export)
1037                 return push_refs_with_export(transport, remote_refs, flags);
1038
1039         return -1;
1040 }
1041
1042
1043 static int has_attribute(const char *attrs, const char *attr)
1044 {
1045         int len;
1046         if (!attrs)
1047                 return 0;
1048
1049         len = strlen(attr);
1050         for (;;) {
1051                 const char *space = strchrnul(attrs, ' ');
1052                 if (len == space - attrs && !strncmp(attrs, attr, len))
1053                         return 1;
1054                 if (!*space)
1055                         return 0;
1056                 attrs = space + 1;
1057         }
1058 }
1059
1060 static struct ref *get_refs_list(struct transport *transport, int for_push,
1061                                  const struct argv_array *ref_prefixes)
1062 {
1063         struct helper_data *data = transport->data;
1064         struct child_process *helper;
1065         struct ref *ret = NULL;
1066         struct ref **tail = &ret;
1067         struct ref *posn;
1068         struct strbuf buf = STRBUF_INIT;
1069
1070         helper = get_helper(transport);
1071
1072         if (process_connect(transport, for_push)) {
1073                 do_take_over(transport);
1074                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1075         }
1076
1077         if (data->push && for_push)
1078                 write_str_in_full(helper->in, "list for-push\n");
1079         else
1080                 write_str_in_full(helper->in, "list\n");
1081
1082         while (1) {
1083                 char *eov, *eon;
1084                 if (recvline(data, &buf))
1085                         exit(128);
1086
1087                 if (!*buf.buf)
1088                         break;
1089
1090                 eov = strchr(buf.buf, ' ');
1091                 if (!eov)
1092                         die(_("malformed response in ref list: %s"), buf.buf);
1093                 eon = strchr(eov + 1, ' ');
1094                 *eov = '\0';
1095                 if (eon)
1096                         *eon = '\0';
1097                 *tail = alloc_ref(eov + 1);
1098                 if (buf.buf[0] == '@')
1099                         (*tail)->symref = xstrdup(buf.buf + 1);
1100                 else if (buf.buf[0] != '?')
1101                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1102                 if (eon) {
1103                         if (has_attribute(eon + 1, "unchanged")) {
1104                                 (*tail)->status |= REF_STATUS_UPTODATE;
1105                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1106                                         die(_("could not read ref %s"),
1107                                             (*tail)->name);
1108                         }
1109                 }
1110                 tail = &((*tail)->next);
1111         }
1112         if (debug)
1113                 fprintf(stderr, "Debug: Read ref listing.\n");
1114         strbuf_release(&buf);
1115
1116         for (posn = ret; posn; posn = posn->next)
1117                 resolve_remote_symref(posn, ret);
1118
1119         return ret;
1120 }
1121
1122 static struct transport_vtable vtable = {
1123         0,
1124         set_helper_option,
1125         get_refs_list,
1126         fetch,
1127         push_refs,
1128         connect_helper,
1129         release_helper
1130 };
1131
1132 int transport_helper_init(struct transport *transport, const char *name)
1133 {
1134         struct helper_data *data = xcalloc(1, sizeof(*data));
1135         data->name = name;
1136
1137         transport_check_allowed(name);
1138
1139         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1140                 debug = 1;
1141
1142         transport->data = data;
1143         transport->vtable = &vtable;
1144         transport->smart_options = &(data->transport_options);
1145         return 0;
1146 }
1147
1148 /*
1149  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1150  * buffer less), so attempt reads and writes with up to that size.
1151  */
1152 #define BUFFERSIZE 65536
1153 /* This should be enough to hold debugging message. */
1154 #define PBUFFERSIZE 8192
1155
1156 /* Print bidirectional transfer loop debug message. */
1157 __attribute__((format (printf, 1, 2)))
1158 static void transfer_debug(const char *fmt, ...)
1159 {
1160         /*
1161          * NEEDSWORK: This function is sometimes used from multiple threads, and
1162          * we end up using debug_enabled racily. That "should not matter" since
1163          * we always write the same value, but it's still wrong. This function
1164          * is listed in .tsan-suppressions for the time being.
1165          */
1166
1167         va_list args;
1168         char msgbuf[PBUFFERSIZE];
1169         static int debug_enabled = -1;
1170
1171         if (debug_enabled < 0)
1172                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1173         if (!debug_enabled)
1174                 return;
1175
1176         va_start(args, fmt);
1177         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1178         va_end(args);
1179         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1180 }
1181
1182 /* Stream state: More data may be coming in this direction. */
1183 #define SSTATE_TRANSFERRING 0
1184 /*
1185  * Stream state: No more data coming in this direction, flushing rest of
1186  * data.
1187  */
1188 #define SSTATE_FLUSHING 1
1189 /* Stream state: Transfer in this direction finished. */
1190 #define SSTATE_FINISHED 2
1191
1192 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1193 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1194 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1195
1196 /* Unidirectional transfer. */
1197 struct unidirectional_transfer {
1198         /* Source */
1199         int src;
1200         /* Destination */
1201         int dest;
1202         /* Is source socket? */
1203         int src_is_sock;
1204         /* Is destination socket? */
1205         int dest_is_sock;
1206         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1207         int state;
1208         /* Buffer. */
1209         char buf[BUFFERSIZE];
1210         /* Buffer used. */
1211         size_t bufuse;
1212         /* Name of source. */
1213         const char *src_name;
1214         /* Name of destination. */
1215         const char *dest_name;
1216 };
1217
1218 /* Closes the target (for writing) if transfer has finished. */
1219 static void udt_close_if_finished(struct unidirectional_transfer *t)
1220 {
1221         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1222                 t->state = SSTATE_FINISHED;
1223                 if (t->dest_is_sock)
1224                         shutdown(t->dest, SHUT_WR);
1225                 else
1226                         close(t->dest);
1227                 transfer_debug("Closed %s.", t->dest_name);
1228         }
1229 }
1230
1231 /*
1232  * Tries to read data from source into buffer. If buffer is full,
1233  * no data is read. Returns 0 on success, -1 on error.
1234  */
1235 static int udt_do_read(struct unidirectional_transfer *t)
1236 {
1237         ssize_t bytes;
1238
1239         if (t->bufuse == BUFFERSIZE)
1240                 return 0;       /* No space for more. */
1241
1242         transfer_debug("%s is readable", t->src_name);
1243         bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1244         if (bytes < 0) {
1245                 error_errno(_("read(%s) failed"), t->src_name);
1246                 return -1;
1247         } else if (bytes == 0) {
1248                 transfer_debug("%s EOF (with %i bytes in buffer)",
1249                         t->src_name, (int)t->bufuse);
1250                 t->state = SSTATE_FLUSHING;
1251         } else if (bytes > 0) {
1252                 t->bufuse += bytes;
1253                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1254                         (int)bytes, t->src_name, (int)t->bufuse);
1255         }
1256         return 0;
1257 }
1258
1259 /* Tries to write data from buffer into destination. If buffer is empty,
1260  * no data is written. Returns 0 on success, -1 on error.
1261  */
1262 static int udt_do_write(struct unidirectional_transfer *t)
1263 {
1264         ssize_t bytes;
1265
1266         if (t->bufuse == 0)
1267                 return 0;       /* Nothing to write. */
1268
1269         transfer_debug("%s is writable", t->dest_name);
1270         bytes = xwrite(t->dest, t->buf, t->bufuse);
1271         if (bytes < 0) {
1272                 error_errno(_("write(%s) failed"), t->dest_name);
1273                 return -1;
1274         } else if (bytes > 0) {
1275                 t->bufuse -= bytes;
1276                 if (t->bufuse)
1277                         memmove(t->buf, t->buf + bytes, t->bufuse);
1278                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1279                         (int)bytes, t->dest_name, (int)t->bufuse);
1280         }
1281         return 0;
1282 }
1283
1284
1285 /* State of bidirectional transfer loop. */
1286 struct bidirectional_transfer_state {
1287         /* Direction from program to git. */
1288         struct unidirectional_transfer ptg;
1289         /* Direction from git to program. */
1290         struct unidirectional_transfer gtp;
1291 };
1292
1293 static void *udt_copy_task_routine(void *udt)
1294 {
1295         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1296         while (t->state != SSTATE_FINISHED) {
1297                 if (STATE_NEEDS_READING(t->state))
1298                         if (udt_do_read(t))
1299                                 return NULL;
1300                 if (STATE_NEEDS_WRITING(t->state))
1301                         if (udt_do_write(t))
1302                                 return NULL;
1303                 if (STATE_NEEDS_CLOSING(t->state))
1304                         udt_close_if_finished(t);
1305         }
1306         return udt;     /* Just some non-NULL value. */
1307 }
1308
1309 #ifndef NO_PTHREADS
1310
1311 /*
1312  * Join thread, with appropriate errors on failure. Name is name for the
1313  * thread (for error messages). Returns 0 on success, 1 on failure.
1314  */
1315 static int tloop_join(pthread_t thread, const char *name)
1316 {
1317         int err;
1318         void *tret;
1319         err = pthread_join(thread, &tret);
1320         if (!tret) {
1321                 error(_("%s thread failed"), name);
1322                 return 1;
1323         }
1324         if (err) {
1325                 error(_("%s thread failed to join: %s"), name, strerror(err));
1326                 return 1;
1327         }
1328         return 0;
1329 }
1330
1331 /*
1332  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1333  * -1 on failure.
1334  */
1335 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1336 {
1337         pthread_t gtp_thread;
1338         pthread_t ptg_thread;
1339         int err;
1340         int ret = 0;
1341         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1342                 &s->gtp);
1343         if (err)
1344                 die(_("can't start thread for copying data: %s"), strerror(err));
1345         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1346                 &s->ptg);
1347         if (err)
1348                 die(_("can't start thread for copying data: %s"), strerror(err));
1349
1350         ret |= tloop_join(gtp_thread, "Git to program copy");
1351         ret |= tloop_join(ptg_thread, "Program to git copy");
1352         return ret;
1353 }
1354 #else
1355
1356 /* Close the source and target (for writing) for transfer. */
1357 static void udt_kill_transfer(struct unidirectional_transfer *t)
1358 {
1359         t->state = SSTATE_FINISHED;
1360         /*
1361          * Socket read end left open isn't a disaster if nobody
1362          * attempts to read from it (mingw compat headers do not
1363          * have SHUT_RD)...
1364          *
1365          * We can't fully close the socket since otherwise gtp
1366          * task would first close the socket it sends data to
1367          * while closing the ptg file descriptors.
1368          */
1369         if (!t->src_is_sock)
1370                 close(t->src);
1371         if (t->dest_is_sock)
1372                 shutdown(t->dest, SHUT_WR);
1373         else
1374                 close(t->dest);
1375 }
1376
1377 /*
1378  * Join process, with appropriate errors on failure. Name is name for the
1379  * process (for error messages). Returns 0 on success, 1 on failure.
1380  */
1381 static int tloop_join(pid_t pid, const char *name)
1382 {
1383         int tret;
1384         if (waitpid(pid, &tret, 0) < 0) {
1385                 error_errno(_("%s process failed to wait"), name);
1386                 return 1;
1387         }
1388         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1389                 error(_("%s process failed"), name);
1390                 return 1;
1391         }
1392         return 0;
1393 }
1394
1395 /*
1396  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1397  * -1 on failure.
1398  */
1399 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1400 {
1401         pid_t pid1, pid2;
1402         int ret = 0;
1403
1404         /* Fork thread #1: git to program. */
1405         pid1 = fork();
1406         if (pid1 < 0)
1407                 die_errno(_("can't start thread for copying data"));
1408         else if (pid1 == 0) {
1409                 udt_kill_transfer(&s->ptg);
1410                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1411         }
1412
1413         /* Fork thread #2: program to git. */
1414         pid2 = fork();
1415         if (pid2 < 0)
1416                 die_errno(_("can't start thread for copying data"));
1417         else if (pid2 == 0) {
1418                 udt_kill_transfer(&s->gtp);
1419                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1420         }
1421
1422         /*
1423          * Close both streams in parent as to not interfere with
1424          * end of file detection and wait for both tasks to finish.
1425          */
1426         udt_kill_transfer(&s->gtp);
1427         udt_kill_transfer(&s->ptg);
1428         ret |= tloop_join(pid1, "Git to program copy");
1429         ret |= tloop_join(pid2, "Program to git copy");
1430         return ret;
1431 }
1432 #endif
1433
1434 /*
1435  * Copies data from stdin to output and from input to stdout simultaneously.
1436  * Additionally filtering through given filter. If filter is NULL, uses
1437  * identity filter.
1438  */
1439 int bidirectional_transfer_loop(int input, int output)
1440 {
1441         struct bidirectional_transfer_state state;
1442
1443         /* Fill the state fields. */
1444         state.ptg.src = input;
1445         state.ptg.dest = 1;
1446         state.ptg.src_is_sock = (input == output);
1447         state.ptg.dest_is_sock = 0;
1448         state.ptg.state = SSTATE_TRANSFERRING;
1449         state.ptg.bufuse = 0;
1450         state.ptg.src_name = "remote input";
1451         state.ptg.dest_name = "stdout";
1452
1453         state.gtp.src = 0;
1454         state.gtp.dest = output;
1455         state.gtp.src_is_sock = 0;
1456         state.gtp.dest_is_sock = (input == output);
1457         state.gtp.state = SSTATE_TRANSFERRING;
1458         state.gtp.bufuse = 0;
1459         state.gtp.src_name = "stdin";
1460         state.gtp.dest_name = "remote output";
1461
1462         return tloop_spawnwait_tasks(&state);
1463 }