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
  15 static int debug;
  16
  17 struct helper_data {
  18         const char *name;
  19         struct child_process *helper;
  20         FILE *out;
  21         unsigned fetch : 1,
  22                 import : 1,
  23                 bidi_import : 1,
  24                 export : 1,
  25                 option : 1,
  26                 push : 1,
  27                 connect : 1,
  28                 signed_tags : 1,
  29                 check_connectivity : 1,
  30                 no_disconnect_req : 1,
  31                 no_private_update : 1;
  32         char *export_marks;
  33         char *import_marks;
  34         /* These go from remote name (as in "list") to private name */
  35         struct refspec *refspecs;
  36         int refspec_nr;
  37         /* Transport options for fetch-pack/send-pack (should one of
  38          * those be invoked).
  39          */
  40         struct git_transport_options transport_options;
  41 };
  42
  43 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  44 {
  45         if (debug)
  46                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  47         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  48                 != buffer->len)
  49                 die_errno("Full write to remote helper failed");
  50 }
  51
  52 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  53 {
  54         strbuf_reset(buffer);
  55         if (debug)
  56                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  57         if (strbuf_getline(buffer, helper) == EOF) {
  58                 if (debug)
  59                         fprintf(stderr, "Debug: Remote helper quit.\n");
  60                 return 1;
  61         }
  62
  63         if (debug)
  64                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  65         return 0;
  66 }
  67
  68 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  69 {
  70         return recvline_fh(helper->out, buffer, helper->name);
  71 }
  72
  73 static void write_constant(int fd, const char *str)
  74 {
  75         if (debug)
  76                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  77         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  78                 die_errno("Full write to remote helper failed");
  79 }
  80
  81 static const char *remove_ext_force(const char *url)
  82 {
  83         if (url) {
  84                 const char *colon = strchr(url, ':');
  85                 if (colon && colon[1] == ':')
  86                         return colon + 2;
  87         }
  88         return url;
  89 }
  90
  91 static void do_take_over(struct transport *transport)
  92 {
  93         struct helper_data *data;
  94         data = (struct helper_data *)transport->data;
  95         transport_take_over(transport, data->helper);
  96         fclose(data->out);
  97         free(data);
  98 }
  99
 100 static void standard_options(struct transport *t);
 101
 102 static struct child_process *get_helper(struct transport *transport)
 103 {
 104         struct helper_data *data = transport->data;
 105         struct strbuf buf = STRBUF_INIT;
 106         struct child_process *helper;
 107         const char **refspecs = NULL;
 108         int refspec_nr = 0;
 109         int refspec_alloc = 0;
 110         int duped;
 111         int code;
 112
 113         if (data->helper)
 114                 return data->helper;
 115
 116         helper = xmalloc(sizeof(*helper));
 117         child_process_init(helper);
 118         helper->in = -1;
 119         helper->out = -1;
 120         helper->err = 0;
 121         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 122         argv_array_push(&helper->args, transport->remote->name);
 123         argv_array_push(&helper->args, remove_ext_force(transport->url));
 124         helper->git_cmd = 0;
 125         helper->silent_exec_failure = 1;
 126
 127         if (have_git_dir())
 128                 argv_array_pushf(&helper->env_array, "%s=%s",
 129                                  GIT_DIR_ENVIRONMENT, get_git_dir());
 130
 131         code = start_command(helper);
 132         if (code < 0 && errno == ENOENT)
 133                 die("Unable to find remote helper for '%s'", data->name);
 134         else if (code != 0)
 135                 exit(code);
 136
 137         data->helper = helper;
 138         data->no_disconnect_req = 0;
 139
 140         /*
 141          * Open the output as FILE* so strbuf_getline_*() family of
 142          * functions can be used.
 143          * Do this with duped fd because fclose() will close the fd,
 144          * and stuff like taking over will require the fd to remain.
 145          */
 146         duped = dup(helper->out);
 147         if (duped < 0)
 148                 die_errno("Can't dup helper output fd");
 149         data->out = xfdopen(duped, "r");
 150
 151         write_constant(helper->in, "capabilities\n");
 152
 153         while (1) {
 154                 const char *capname, *arg;
 155                 int mandatory = 0;
 156                 if (recvline(data, &buf))
 157                         exit(128);
 158
 159                 if (!*buf.buf)
 160                         break;
 161
 162                 if (*buf.buf == '*') {
 163                         capname = buf.buf + 1;
 164                         mandatory = 1;
 165                 } else
 166                         capname = buf.buf;
 167
 168                 if (debug)
 169                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 170                 if (!strcmp(capname, "fetch"))
 171                         data->fetch = 1;
 172                 else if (!strcmp(capname, "option"))
 173                         data->option = 1;
 174                 else if (!strcmp(capname, "push"))
 175                         data->push = 1;
 176                 else if (!strcmp(capname, "import"))
 177                         data->import = 1;
 178                 else if (!strcmp(capname, "bidi-import"))
 179                         data->bidi_import = 1;
 180                 else if (!strcmp(capname, "export"))
 181                         data->export = 1;
 182                 else if (!strcmp(capname, "check-connectivity"))
 183                         data->check_connectivity = 1;
 184                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 185                         ALLOC_GROW(refspecs,
 186                                    refspec_nr + 1,
 187                                    refspec_alloc);
 188                         refspecs[refspec_nr++] = xstrdup(arg);
 189                 } else if (!strcmp(capname, "connect")) {
 190                         data->connect = 1;
 191                 } else if (!strcmp(capname, "signed-tags")) {
 192                         data->signed_tags = 1;
 193                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 194                         data->export_marks = xstrdup(arg);
 195                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 196                         data->import_marks = xstrdup(arg);
 197                 } else if (starts_with(capname, "no-private-update")) {
 198                         data->no_private_update = 1;
 199                 } else if (mandatory) {
 200                         die("Unknown mandatory capability %s. This remote "
 201                             "helper probably needs newer version of Git.",
 202                             capname);
 203                 }
 204         }
 205         if (refspecs) {
 206                 int i;
 207                 data->refspec_nr = refspec_nr;
 208                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 209                 for (i = 0; i < refspec_nr; i++)
 210                         free((char *)refspecs[i]);
 211                 free(refspecs);
 212         } else if (data->import || data->bidi_import || data->export) {
 213                 warning("This remote helper should implement refspec capability.");
 214         }
 215         strbuf_release(&buf);
 216         if (debug)
 217                 fprintf(stderr, "Debug: Capabilities complete.\n");
 218         standard_options(transport);
 219         return data->helper;
 220 }
 221
 222 static int disconnect_helper(struct transport *transport)
 223 {
 224         struct helper_data *data = transport->data;
 225         int res = 0;
 226
 227         if (data->helper) {
 228                 if (debug)
 229                         fprintf(stderr, "Debug: Disconnecting.\n");
 230                 if (!data->no_disconnect_req) {
 231                         /*
 232                          * Ignore write errors; there's nothing we can do,
 233                          * since we're about to close the pipe anyway. And the
 234                          * most likely error is EPIPE due to the helper dying
 235                          * to report an error itself.
 236                          */
 237                         sigchain_push(SIGPIPE, SIG_IGN);
 238                         xwrite(data->helper->in, "\n", 1);
 239                         sigchain_pop(SIGPIPE);
 240                 }
 241                 close(data->helper->in);
 242                 close(data->helper->out);
 243                 fclose(data->out);
 244                 res = finish_command(data->helper);
 245                 FREE_AND_NULL(data->helper);
 246         }
 247         return res;
 248 }
 249
 250 static const char *unsupported_options[] = {
 251         TRANS_OPT_UPLOADPACK,
 252         TRANS_OPT_RECEIVEPACK,
 253         TRANS_OPT_THIN,
 254         TRANS_OPT_KEEP
 255         };
 256
 257 static const char *boolean_options[] = {
 258         TRANS_OPT_THIN,
 259         TRANS_OPT_KEEP,
 260         TRANS_OPT_FOLLOWTAGS,
 261         TRANS_OPT_DEEPEN_RELATIVE
 262         };
 263
 264 static int strbuf_set_helper_option(struct helper_data *data,
 265                                     struct strbuf *buf)
 266 {
 267         int ret;
 268
 269         sendline(data, buf);
 270         if (recvline(data, buf))
 271                 exit(128);
 272
 273         if (!strcmp(buf->buf, "ok"))
 274                 ret = 0;
 275         else if (starts_with(buf->buf, "error"))
 276                 ret = -1;
 277         else if (!strcmp(buf->buf, "unsupported"))
 278                 ret = 1;
 279         else {
 280                 warning("%s unexpectedly said: '%s'", data->name, buf->buf);
 281                 ret = 1;
 282         }
 283         return ret;
 284 }
 285
 286 static int string_list_set_helper_option(struct helper_data *data,
 287                                          const char *name,
 288                                          struct string_list *list)
 289 {
 290         struct strbuf buf = STRBUF_INIT;
 291         int i, ret = 0;
 292
 293         for (i = 0; i < list->nr; i++) {
 294                 strbuf_addf(&buf, "option %s ", name);
 295                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 296                 strbuf_addch(&buf, '\n');
 297
 298                 if ((ret = strbuf_set_helper_option(data, &buf)))
 299                         break;
 300                 strbuf_reset(&buf);
 301         }
 302         strbuf_release(&buf);
 303         return ret;
 304 }
 305
 306 static int set_helper_option(struct transport *transport,
 307                           const char *name, const char *value)
 308 {
 309         struct helper_data *data = transport->data;
 310         struct strbuf buf = STRBUF_INIT;
 311         int i, ret, is_bool = 0;
 312
 313         get_helper(transport);
 314
 315         if (!data->option)
 316                 return 1;
 317
 318         if (!strcmp(name, "deepen-not"))
 319                 return string_list_set_helper_option(data, name,
 320                                                      (struct string_list *)value);
 321
 322         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 323                 if (!strcmp(name, unsupported_options[i]))
 324                         return 1;
 325         }
 326
 327         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 328                 if (!strcmp(name, boolean_options[i])) {
 329                         is_bool = 1;
 330                         break;
 331                 }
 332         }
 333
 334         strbuf_addf(&buf, "option %s ", name);
 335         if (is_bool)
 336                 strbuf_addstr(&buf, value ? "true" : "false");
 337         else
 338                 quote_c_style(value, &buf, NULL, 0);
 339         strbuf_addch(&buf, '\n');
 340
 341         ret = strbuf_set_helper_option(data, &buf);
 342         strbuf_release(&buf);
 343         return ret;
 344 }
 345
 346 static void standard_options(struct transport *t)
 347 {
 348         char buf[16];
 349         int v = t->verbose;
 350
 351         set_helper_option(t, "progress", t->progress ? "true" : "false");
 352
 353         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 354         set_helper_option(t, "verbosity", buf);
 355
 356         switch (t->family) {
 357         case TRANSPORT_FAMILY_ALL:
 358                 /*
 359                  * this is already the default,
 360                  * do not break old remote helpers by setting "all" here
 361                  */
 362                 break;
 363         case TRANSPORT_FAMILY_IPV4:
 364                 set_helper_option(t, "family", "ipv4");
 365                 break;
 366         case TRANSPORT_FAMILY_IPV6:
 367                 set_helper_option(t, "family", "ipv6");
 368                 break;
 369         }
 370 }
 371
 372 static int release_helper(struct transport *transport)
 373 {
 374         int res = 0;
 375         struct helper_data *data = transport->data;
 376         free_refspec(data->refspec_nr, data->refspecs);
 377         data->refspecs = NULL;
 378         res = disconnect_helper(transport);
 379         free(transport->data);
 380         return res;
 381 }
 382
 383 static int fetch_with_fetch(struct transport *transport,
 384                             int nr_heads, struct ref **to_fetch)
 385 {
 386         struct helper_data *data = transport->data;
 387         int i;
 388         struct strbuf buf = STRBUF_INIT;
 389
 390         for (i = 0; i < nr_heads; i++) {
 391                 const struct ref *posn = to_fetch[i];
 392                 if (posn->status & REF_STATUS_UPTODATE)
 393                         continue;
 394
 395                 strbuf_addf(&buf, "fetch %s %s\n",
 396                             oid_to_hex(&posn->old_oid),
 397                             posn->symref ? posn->symref : posn->name);
 398         }
 399
 400         strbuf_addch(&buf, '\n');
 401         sendline(data, &buf);
 402
 403         while (1) {
 404                 if (recvline(data, &buf))
 405                         exit(128);
 406
 407                 if (starts_with(buf.buf, "lock ")) {
 408                         const char *name = buf.buf + 5;
 409                         if (transport->pack_lockfile)
 410                                 warning("%s also locked %s", data->name, name);
 411                         else
 412                                 transport->pack_lockfile = xstrdup(name);
 413                 }
 414                 else if (data->check_connectivity &&
 415                          data->transport_options.check_self_contained_and_connected &&
 416                          !strcmp(buf.buf, "connectivity-ok"))
 417                         data->transport_options.self_contained_and_connected = 1;
 418                 else if (!buf.len)
 419                         break;
 420                 else
 421                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 422         }
 423         strbuf_release(&buf);
 424         return 0;
 425 }
 426
 427 static int get_importer(struct transport *transport, struct child_process *fastimport)
 428 {
 429         struct child_process *helper = get_helper(transport);
 430         struct helper_data *data = transport->data;
 431         int cat_blob_fd, code;
 432         child_process_init(fastimport);
 433         fastimport->in = helper->out;
 434         argv_array_push(&fastimport->args, "fast-import");
 435         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 436
 437         if (data->bidi_import) {
 438                 cat_blob_fd = xdup(helper->in);
 439                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 440         }
 441         fastimport->git_cmd = 1;
 442
 443         code = start_command(fastimport);
 444         return code;
 445 }
 446
 447 static int get_exporter(struct transport *transport,
 448                         struct child_process *fastexport,
 449                         struct string_list *revlist_args)
 450 {
 451         struct helper_data *data = transport->data;
 452         struct child_process *helper = get_helper(transport);
 453         int i;
 454
 455         child_process_init(fastexport);
 456
 457         /* we need to duplicate helper->in because we want to use it after
 458          * fastexport is done with it. */
 459         fastexport->out = dup(helper->in);
 460         argv_array_push(&fastexport->args, "fast-export");
 461         argv_array_push(&fastexport->args, "--use-done-feature");
 462         argv_array_push(&fastexport->args, data->signed_tags ?
 463                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 464         if (data->export_marks)
 465                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 466         if (data->import_marks)
 467                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 468
 469         for (i = 0; i < revlist_args->nr; i++)
 470                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 471
 472         fastexport->git_cmd = 1;
 473         return start_command(fastexport);
 474 }
 475
 476 static int fetch_with_import(struct transport *transport,
 477                              int nr_heads, struct ref **to_fetch)
 478 {
 479         struct child_process fastimport;
 480         struct helper_data *data = transport->data;
 481         int i;
 482         struct ref *posn;
 483         struct strbuf buf = STRBUF_INIT;
 484
 485         get_helper(transport);
 486
 487         if (get_importer(transport, &fastimport))
 488                 die("Couldn't run fast-import");
 489
 490         for (i = 0; i < nr_heads; i++) {
 491                 posn = to_fetch[i];
 492                 if (posn->status & REF_STATUS_UPTODATE)
 493                         continue;
 494
 495                 strbuf_addf(&buf, "import %s\n",
 496                             posn->symref ? posn->symref : posn->name);
 497                 sendline(data, &buf);
 498                 strbuf_reset(&buf);
 499         }
 500
 501         write_constant(data->helper->in, "\n");
 502         /*
 503          * remote-helpers that advertise the bidi-import capability are required to
 504          * buffer the complete batch of import commands until this newline before
 505          * sending data to fast-import.
 506          * These helpers read back data from fast-import on their stdin, which could
 507          * be mixed with import commands, otherwise.
 508          */
 509
 510         if (finish_command(&fastimport))
 511                 die("Error while running fast-import");
 512
 513         /*
 514          * The fast-import stream of a remote helper that advertises
 515          * the "refspec" capability writes to the refs named after the
 516          * right hand side of the first refspec matching each ref we
 517          * were fetching.
 518          *
 519          * (If no "refspec" capability was specified, for historical
 520          * reasons we default to the equivalent of *:*.)
 521          *
 522          * Store the result in to_fetch[i].old_sha1.  Callers such
 523          * as "git fetch" can use the value to write feedback to the
 524          * terminal, populate FETCH_HEAD, and determine what new value
 525          * should be written to peer_ref if the update is a
 526          * fast-forward or this is a forced update.
 527          */
 528         for (i = 0; i < nr_heads; i++) {
 529                 char *private, *name;
 530                 posn = to_fetch[i];
 531                 if (posn->status & REF_STATUS_UPTODATE)
 532                         continue;
 533                 name = posn->symref ? posn->symref : posn->name;
 534                 if (data->refspecs)
 535                         private = apply_refspecs(data->refspecs, data->refspec_nr, name);
 536                 else
 537                         private = xstrdup(name);
 538                 if (private) {
 539                         if (read_ref(private, posn->old_oid.hash) < 0)
 540                                 die("Could not read ref %s", private);
 541                         free(private);
 542                 }
 543         }
 544         strbuf_release(&buf);
 545         return 0;
 546 }
 547
 548 static int process_connect_service(struct transport *transport,
 549                                    const char *name, const char *exec)
 550 {
 551         struct helper_data *data = transport->data;
 552         struct strbuf cmdbuf = STRBUF_INIT;
 553         struct child_process *helper;
 554         int r, duped, ret = 0;
 555         FILE *input;
 556
 557         helper = get_helper(transport);
 558
 559         /*
 560          * Yes, dup the pipe another time, as we need unbuffered version
 561          * of input pipe as FILE*. fclose() closes the underlying fd and
 562          * stream buffering only can be changed before first I/O operation
 563          * on it.
 564          */
 565         duped = dup(helper->out);
 566         if (duped < 0)
 567                 die_errno("Can't dup helper output fd");
 568         input = xfdopen(duped, "r");
 569         setvbuf(input, NULL, _IONBF, 0);
 570
 571         /*
 572          * Handle --upload-pack and friends. This is fire and forget...
 573          * just warn if it fails.
 574          */
 575         if (strcmp(name, exec)) {
 576                 r = set_helper_option(transport, "servpath", exec);
 577                 if (r > 0)
 578                         warning("Setting remote service path not supported by protocol.");
 579                 else if (r < 0)
 580                         warning("Invalid remote service path.");
 581         }
 582
 583         if (data->connect)
 584                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 585         else
 586                 goto exit;
 587
 588         sendline(data, &cmdbuf);
 589         if (recvline_fh(input, &cmdbuf, name))
 590                 exit(128);
 591
 592         if (!strcmp(cmdbuf.buf, "")) {
 593                 data->no_disconnect_req = 1;
 594                 if (debug)
 595                         fprintf(stderr, "Debug: Smart transport connection "
 596                                 "ready.\n");
 597                 ret = 1;
 598         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 599                 if (debug)
 600                         fprintf(stderr, "Debug: Falling back to dumb "
 601                                 "transport.\n");
 602         } else
 603                 die("Unknown response to connect: %s",
 604                         cmdbuf.buf);
 605
 606 exit:
 607         fclose(input);
 608         return ret;
 609 }
 610
 611 static int process_connect(struct transport *transport,
 612                                      int for_push)
 613 {
 614         struct helper_data *data = transport->data;
 615         const char *name;
 616         const char *exec;
 617
 618         name = for_push ? "git-receive-pack" : "git-upload-pack";
 619         if (for_push)
 620                 exec = data->transport_options.receivepack;
 621         else
 622                 exec = data->transport_options.uploadpack;
 623
 624         return process_connect_service(transport, name, exec);
 625 }
 626
 627 static int connect_helper(struct transport *transport, const char *name,
 628                    const char *exec, int fd[2])
 629 {
 630         struct helper_data *data = transport->data;
 631
 632         /* Get_helper so connect is inited. */
 633         get_helper(transport);
 634         if (!data->connect)
 635                 die("Operation not supported by protocol.");
 636
 637         if (!process_connect_service(transport, name, exec))
 638                 die("Can't connect to subservice %s.", name);
 639
 640         fd[0] = data->helper->out;
 641         fd[1] = data->helper->in;
 642         return 0;
 643 }
 644
 645 static int fetch(struct transport *transport,
 646                  int nr_heads, struct ref **to_fetch)
 647 {
 648         struct helper_data *data = transport->data;
 649         int i, count;
 650
 651         if (process_connect(transport, 0)) {
 652                 do_take_over(transport);
 653                 return transport->fetch(transport, nr_heads, to_fetch);
 654         }
 655
 656         count = 0;
 657         for (i = 0; i < nr_heads; i++)
 658                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 659                         count++;
 660
 661         if (!count)
 662                 return 0;
 663
 664         if (data->check_connectivity &&
 665             data->transport_options.check_self_contained_and_connected)
 666                 set_helper_option(transport, "check-connectivity", "true");
 667
 668         if (transport->cloning)
 669                 set_helper_option(transport, "cloning", "true");
 670
 671         if (data->transport_options.update_shallow)
 672                 set_helper_option(transport, "update-shallow", "true");
 673
 674         if (data->fetch)
 675                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 676
 677         if (data->import)
 678                 return fetch_with_import(transport, nr_heads, to_fetch);
 679
 680         return -1;
 681 }
 682
 683 static int push_update_ref_status(struct strbuf *buf,
 684                                    struct ref **ref,
 685                                    struct ref *remote_refs)
 686 {
 687         char *refname, *msg;
 688         int status, forced = 0;
 689
 690         if (starts_with(buf->buf, "ok ")) {
 691                 status = REF_STATUS_OK;
 692                 refname = buf->buf + 3;
 693         } else if (starts_with(buf->buf, "error ")) {
 694                 status = REF_STATUS_REMOTE_REJECT;
 695                 refname = buf->buf + 6;
 696         } else
 697                 die("expected ok/error, helper said '%s'", buf->buf);
 698
 699         msg = strchr(refname, ' ');
 700         if (msg) {
 701                 struct strbuf msg_buf = STRBUF_INIT;
 702                 const char *end;
 703
 704                 *msg++ = '\0';
 705                 if (!unquote_c_style(&msg_buf, msg, &end))
 706                         msg = strbuf_detach(&msg_buf, NULL);
 707                 else
 708                         msg = xstrdup(msg);
 709                 strbuf_release(&msg_buf);
 710
 711                 if (!strcmp(msg, "no match")) {
 712                         status = REF_STATUS_NONE;
 713                         FREE_AND_NULL(msg);
 714                 }
 715                 else if (!strcmp(msg, "up to date")) {
 716                         status = REF_STATUS_UPTODATE;
 717                         FREE_AND_NULL(msg);
 718                 }
 719                 else if (!strcmp(msg, "non-fast forward")) {
 720                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 721                         FREE_AND_NULL(msg);
 722                 }
 723                 else if (!strcmp(msg, "already exists")) {
 724                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 725                         FREE_AND_NULL(msg);
 726                 }
 727                 else if (!strcmp(msg, "fetch first")) {
 728                         status = REF_STATUS_REJECT_FETCH_FIRST;
 729                         FREE_AND_NULL(msg);
 730                 }
 731                 else if (!strcmp(msg, "needs force")) {
 732                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 733                         FREE_AND_NULL(msg);
 734                 }
 735                 else if (!strcmp(msg, "stale info")) {
 736                         status = REF_STATUS_REJECT_STALE;
 737                         FREE_AND_NULL(msg);
 738                 }
 739                 else if (!strcmp(msg, "forced update")) {
 740                         forced = 1;
 741                         FREE_AND_NULL(msg);
 742                 }
 743         }
 744
 745         if (*ref)
 746                 *ref = find_ref_by_name(*ref, refname);
 747         if (!*ref)
 748                 *ref = find_ref_by_name(remote_refs, refname);
 749         if (!*ref) {
 750                 warning("helper reported unexpected status of %s", refname);
 751                 return 1;
 752         }
 753
 754         if ((*ref)->status != REF_STATUS_NONE) {
 755                 /*
 756                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 757                  * status reported by the remote helper if the latter is 'no match'.
 758                  */
 759                 if (status == REF_STATUS_NONE)
 760                         return 1;
 761         }
 762
 763         (*ref)->status = status;
 764         (*ref)->forced_update |= forced;
 765         (*ref)->remote_status = msg;
 766         return !(status == REF_STATUS_OK);
 767 }
 768
 769 static int push_update_refs_status(struct helper_data *data,
 770                                     struct ref *remote_refs,
 771                                     int flags)
 772 {
 773         struct strbuf buf = STRBUF_INIT;
 774         struct ref *ref = remote_refs;
 775         int ret = 0;
 776
 777         for (;;) {
 778                 char *private;
 779
 780                 if (recvline(data, &buf)) {
 781                         ret = 1;
 782                         break;
 783                 }
 784
 785                 if (!buf.len)
 786                         break;
 787
 788                 if (push_update_ref_status(&buf, &ref, remote_refs))
 789                         continue;
 790
 791                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 792                         continue;
 793
 794                 /* propagate back the update to the remote namespace */
 795                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 796                 if (!private)
 797                         continue;
 798                 update_ref("update by helper", private, ref->new_oid.hash, NULL, 0, 0);
 799                 free(private);
 800         }
 801         strbuf_release(&buf);
 802         return ret;
 803 }
 804
 805 static void set_common_push_options(struct transport *transport,
 806                                    const char *name, int flags)
 807 {
 808         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 809                 if (set_helper_option(transport, "dry-run", "true") != 0)
 810                         die("helper %s does not support dry-run", name);
 811         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 812                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 813                         die("helper %s does not support --signed", name);
 814         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 815                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 816                         die("helper %s does not support --signed=if-asked", name);
 817         }
 818
 819         if (flags & TRANSPORT_PUSH_OPTIONS) {
 820                 struct string_list_item *item;
 821                 for_each_string_list_item(item, transport->push_options)
 822                         if (set_helper_option(transport, "push-option", item->string) != 0)
 823                                 die("helper %s does not support 'push-option'", name);
 824         }
 825 }
 826
 827 static int push_refs_with_push(struct transport *transport,
 828                                struct ref *remote_refs, int flags)
 829 {
 830         int force_all = flags & TRANSPORT_PUSH_FORCE;
 831         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 832         struct helper_data *data = transport->data;
 833         struct strbuf buf = STRBUF_INIT;
 834         struct ref *ref;
 835         struct string_list cas_options = STRING_LIST_INIT_DUP;
 836         struct string_list_item *cas_option;
 837
 838         get_helper(transport);
 839         if (!data->push)
 840                 return 1;
 841
 842         for (ref = remote_refs; ref; ref = ref->next) {
 843                 if (!ref->peer_ref && !mirror)
 844                         continue;
 845
 846                 /* Check for statuses set by set_ref_status_for_push() */
 847                 switch (ref->status) {
 848                 case REF_STATUS_REJECT_NONFASTFORWARD:
 849                 case REF_STATUS_REJECT_STALE:
 850                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 851                 case REF_STATUS_UPTODATE:
 852                         continue;
 853                 default:
 854                         ; /* do nothing */
 855                 }
 856
 857                 if (force_all)
 858                         ref->force = 1;
 859
 860                 strbuf_addstr(&buf, "push ");
 861                 if (!ref->deletion) {
 862                         if (ref->force)
 863                                 strbuf_addch(&buf, '+');
 864                         if (ref->peer_ref)
 865                                 strbuf_addstr(&buf, ref->peer_ref->name);
 866                         else
 867                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 868                 }
 869                 strbuf_addch(&buf, ':');
 870                 strbuf_addstr(&buf, ref->name);
 871                 strbuf_addch(&buf, '\n');
 872
 873                 /*
 874                  * The "--force-with-lease" options without explicit
 875                  * values to expect have already been expanded into
 876                  * the ref->old_oid_expect[] field; we can ignore
 877                  * transport->smart_options->cas altogether and instead
 878                  * can enumerate them from the refs.
 879                  */
 880                 if (ref->expect_old_sha1) {
 881                         struct strbuf cas = STRBUF_INIT;
 882                         strbuf_addf(&cas, "%s:%s",
 883                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 884                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 885                 }
 886         }
 887         if (buf.len == 0) {
 888                 string_list_clear(&cas_options, 0);
 889                 return 0;
 890         }
 891
 892         for_each_string_list_item(cas_option, &cas_options)
 893                 set_helper_option(transport, "cas", cas_option->string);
 894         set_common_push_options(transport, data->name, flags);
 895
 896         strbuf_addch(&buf, '\n');
 897         sendline(data, &buf);
 898         strbuf_release(&buf);
 899
 900         return push_update_refs_status(data, remote_refs, flags);
 901 }
 902
 903 static int push_refs_with_export(struct transport *transport,
 904                 struct ref *remote_refs, int flags)
 905 {
 906         struct ref *ref;
 907         struct child_process *helper, exporter;
 908         struct helper_data *data = transport->data;
 909         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 910         struct strbuf buf = STRBUF_INIT;
 911
 912         if (!data->refspecs)
 913                 die("remote-helper doesn't support push; refspec needed");
 914
 915         set_common_push_options(transport, data->name, flags);
 916         if (flags & TRANSPORT_PUSH_FORCE) {
 917                 if (set_helper_option(transport, "force", "true") != 0)
 918                         warning("helper %s does not support 'force'", data->name);
 919         }
 920
 921         helper = get_helper(transport);
 922
 923         write_constant(helper->in, "export\n");
 924
 925         for (ref = remote_refs; ref; ref = ref->next) {
 926                 char *private;
 927                 struct object_id oid;
 928
 929                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 930                 if (private && !get_sha1(private, oid.hash)) {
 931                         strbuf_addf(&buf, "^%s", private);
 932                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 933                         oidcpy(&ref->old_oid, &oid);
 934                 }
 935                 free(private);
 936
 937                 if (ref->peer_ref) {
 938                         if (strcmp(ref->name, ref->peer_ref->name)) {
 939                                 if (!ref->deletion) {
 940                                         const char *name;
 941                                         int flag;
 942
 943                                         /* Follow symbolic refs (mainly for HEAD). */
 944                                         name = resolve_ref_unsafe(
 945                                                  ref->peer_ref->name,
 946                                                  RESOLVE_REF_READING,
 947                                                  oid.hash, &flag);
 948                                         if (!name || !(flag & REF_ISSYMREF))
 949                                                 name = ref->peer_ref->name;
 950
 951                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 952                                 } else
 953                                         strbuf_addf(&buf, ":%s", ref->name);
 954
 955                                 string_list_append(&revlist_args, "--refspec");
 956                                 string_list_append(&revlist_args, buf.buf);
 957                                 strbuf_release(&buf);
 958                         }
 959                         if (!ref->deletion)
 960                                 string_list_append(&revlist_args, ref->peer_ref->name);
 961                 }
 962         }
 963
 964         if (get_exporter(transport, &exporter, &revlist_args))
 965                 die("Couldn't run fast-export");
 966
 967         string_list_clear(&revlist_args, 1);
 968
 969         if (finish_command(&exporter))
 970                 die("Error while running fast-export");
 971         if (push_update_refs_status(data, remote_refs, flags))
 972                 return 1;
 973
 974         if (data->export_marks) {
 975                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 976                 rename(buf.buf, data->export_marks);
 977                 strbuf_release(&buf);
 978         }
 979
 980         return 0;
 981 }
 982
 983 static int push_refs(struct transport *transport,
 984                 struct ref *remote_refs, int flags)
 985 {
 986         struct helper_data *data = transport->data;
 987
 988         if (process_connect(transport, 1)) {
 989                 do_take_over(transport);
 990                 return transport->push_refs(transport, remote_refs, flags);
 991         }
 992
 993         if (!remote_refs) {
 994                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 995                         "Perhaps you should specify a branch such as 'master'.\n");
 996                 return 0;
 997         }
 998
 999         if (data->push)
1000                 return push_refs_with_push(transport, remote_refs, flags);
1001
1002         if (data->export)
1003                 return push_refs_with_export(transport, remote_refs, flags);
1004
1005         return -1;
1006 }
1007
1008
1009 static int has_attribute(const char *attrs, const char *attr) {
1010         int len;
1011         if (!attrs)
1012                 return 0;
1013
1014         len = strlen(attr);
1015         for (;;) {
1016                 const char *space = strchrnul(attrs, ' ');
1017                 if (len == space - attrs && !strncmp(attrs, attr, len))
1018                         return 1;
1019                 if (!*space)
1020                         return 0;
1021                 attrs = space + 1;
1022         }
1023 }
1024
1025 static struct ref *get_refs_list(struct transport *transport, int for_push)
1026 {
1027         struct helper_data *data = transport->data;
1028         struct child_process *helper;
1029         struct ref *ret = NULL;
1030         struct ref **tail = &ret;
1031         struct ref *posn;
1032         struct strbuf buf = STRBUF_INIT;
1033
1034         helper = get_helper(transport);
1035
1036         if (process_connect(transport, for_push)) {
1037                 do_take_over(transport);
1038                 return transport->get_refs_list(transport, for_push);
1039         }
1040
1041         if (data->push && for_push)
1042                 write_str_in_full(helper->in, "list for-push\n");
1043         else
1044                 write_str_in_full(helper->in, "list\n");
1045
1046         while (1) {
1047                 char *eov, *eon;
1048                 if (recvline(data, &buf))
1049                         exit(128);
1050
1051                 if (!*buf.buf)
1052                         break;
1053
1054                 eov = strchr(buf.buf, ' ');
1055                 if (!eov)
1056                         die("Malformed response in ref list: %s", buf.buf);
1057                 eon = strchr(eov + 1, ' ');
1058                 *eov = '\0';
1059                 if (eon)
1060                         *eon = '\0';
1061                 *tail = alloc_ref(eov + 1);
1062                 if (buf.buf[0] == '@')
1063                         (*tail)->symref = xstrdup(buf.buf + 1);
1064                 else if (buf.buf[0] != '?')
1065                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1066                 if (eon) {
1067                         if (has_attribute(eon + 1, "unchanged")) {
1068                                 (*tail)->status |= REF_STATUS_UPTODATE;
1069                                 if (read_ref((*tail)->name,
1070                                              (*tail)->old_oid.hash) < 0)
1071                                         die(_("Could not read ref %s"),
1072                                             (*tail)->name);
1073                         }
1074                 }
1075                 tail = &((*tail)->next);
1076         }
1077         if (debug)
1078                 fprintf(stderr, "Debug: Read ref listing.\n");
1079         strbuf_release(&buf);
1080
1081         for (posn = ret; posn; posn = posn->next)
1082                 resolve_remote_symref(posn, ret);
1083
1084         return ret;
1085 }
1086
1087 int transport_helper_init(struct transport *transport, const char *name)
1088 {
1089         struct helper_data *data = xcalloc(1, sizeof(*data));
1090         data->name = name;
1091
1092         transport_check_allowed(name);
1093
1094         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1095                 debug = 1;
1096
1097         transport->data = data;
1098         transport->set_option = set_helper_option;
1099         transport->get_refs_list = get_refs_list;
1100         transport->fetch = fetch;
1101         transport->push_refs = push_refs;
1102         transport->disconnect = release_helper;
1103         transport->connect = connect_helper;
1104         transport->smart_options = &(data->transport_options);
1105         return 0;
1106 }
1107
1108 /*
1109  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1110  * buffer less), so attempt reads and writes with up to that size.
1111  */
1112 #define BUFFERSIZE 65536
1113 /* This should be enough to hold debugging message. */
1114 #define PBUFFERSIZE 8192
1115
1116 /* Print bidirectional transfer loop debug message. */
1117 __attribute__((format (printf, 1, 2)))
1118 static void transfer_debug(const char *fmt, ...)
1119 {
1120         va_list args;
1121         char msgbuf[PBUFFERSIZE];
1122         static int debug_enabled = -1;
1123
1124         if (debug_enabled < 0)
1125                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1126         if (!debug_enabled)
1127                 return;
1128
1129         va_start(args, fmt);
1130         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1131         va_end(args);
1132         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1133 }
1134
1135 /* Stream state: More data may be coming in this direction. */
1136 #define SSTATE_TRANSFERRING 0
1137 /*
1138  * Stream state: No more data coming in this direction, flushing rest of
1139  * data.
1140  */
1141 #define SSTATE_FLUSHING 1
1142 /* Stream state: Transfer in this direction finished. */
1143 #define SSTATE_FINISHED 2
1144
1145 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1146 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1147 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1148
1149 /* Unidirectional transfer. */
1150 struct unidirectional_transfer {
1151         /* Source */
1152         int src;
1153         /* Destination */
1154         int dest;
1155         /* Is source socket? */
1156         int src_is_sock;
1157         /* Is destination socket? */
1158         int dest_is_sock;
1159         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1160         int state;
1161         /* Buffer. */
1162         char buf[BUFFERSIZE];
1163         /* Buffer used. */
1164         size_t bufuse;
1165         /* Name of source. */
1166         const char *src_name;
1167         /* Name of destination. */
1168         const char *dest_name;
1169 };
1170
1171 /* Closes the target (for writing) if transfer has finished. */
1172 static void udt_close_if_finished(struct unidirectional_transfer *t)
1173 {
1174         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1175                 t->state = SSTATE_FINISHED;
1176                 if (t->dest_is_sock)
1177                         shutdown(t->dest, SHUT_WR);
1178                 else
1179                         close(t->dest);
1180                 transfer_debug("Closed %s.", t->dest_name);
1181         }
1182 }
1183
1184 /*
1185  * Tries to read data from source into buffer. If buffer is full,
1186  * no data is read. Returns 0 on success, -1 on error.
1187  */
1188 static int udt_do_read(struct unidirectional_transfer *t)
1189 {
1190         ssize_t bytes;
1191
1192         if (t->bufuse == BUFFERSIZE)
1193                 return 0;       /* No space for more. */
1194
1195         transfer_debug("%s is readable", t->src_name);
1196         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1197         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1198                 errno != EINTR) {
1199                 error_errno("read(%s) failed", t->src_name);
1200                 return -1;
1201         } else if (bytes == 0) {
1202                 transfer_debug("%s EOF (with %i bytes in buffer)",
1203                         t->src_name, (int)t->bufuse);
1204                 t->state = SSTATE_FLUSHING;
1205         } else if (bytes > 0) {
1206                 t->bufuse += bytes;
1207                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1208                         (int)bytes, t->src_name, (int)t->bufuse);
1209         }
1210         return 0;
1211 }
1212
1213 /* Tries to write data from buffer into destination. If buffer is empty,
1214  * no data is written. Returns 0 on success, -1 on error.
1215  */
1216 static int udt_do_write(struct unidirectional_transfer *t)
1217 {
1218         ssize_t bytes;
1219
1220         if (t->bufuse == 0)
1221                 return 0;       /* Nothing to write. */
1222
1223         transfer_debug("%s is writable", t->dest_name);
1224         bytes = xwrite(t->dest, t->buf, t->bufuse);
1225         if (bytes < 0 && errno != EWOULDBLOCK) {
1226                 error_errno("write(%s) failed", t->dest_name);
1227                 return -1;
1228         } else if (bytes > 0) {
1229                 t->bufuse -= bytes;
1230                 if (t->bufuse)
1231                         memmove(t->buf, t->buf + bytes, t->bufuse);
1232                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1233                         (int)bytes, t->dest_name, (int)t->bufuse);
1234         }
1235         return 0;
1236 }
1237
1238
1239 /* State of bidirectional transfer loop. */
1240 struct bidirectional_transfer_state {
1241         /* Direction from program to git. */
1242         struct unidirectional_transfer ptg;
1243         /* Direction from git to program. */
1244         struct unidirectional_transfer gtp;
1245 };
1246
1247 static void *udt_copy_task_routine(void *udt)
1248 {
1249         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1250         while (t->state != SSTATE_FINISHED) {
1251                 if (STATE_NEEDS_READING(t->state))
1252                         if (udt_do_read(t))
1253                                 return NULL;
1254                 if (STATE_NEEDS_WRITING(t->state))
1255                         if (udt_do_write(t))
1256                                 return NULL;
1257                 if (STATE_NEEDS_CLOSING(t->state))
1258                         udt_close_if_finished(t);
1259         }
1260         return udt;     /* Just some non-NULL value. */
1261 }
1262
1263 #ifndef NO_PTHREADS
1264
1265 /*
1266  * Join thread, with appropriate errors on failure. Name is name for the
1267  * thread (for error messages). Returns 0 on success, 1 on failure.
1268  */
1269 static int tloop_join(pthread_t thread, const char *name)
1270 {
1271         int err;
1272         void *tret;
1273         err = pthread_join(thread, &tret);
1274         if (!tret) {
1275                 error("%s thread failed", name);
1276                 return 1;
1277         }
1278         if (err) {
1279                 error("%s thread failed to join: %s", name, strerror(err));
1280                 return 1;
1281         }
1282         return 0;
1283 }
1284
1285 /*
1286  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1287  * -1 on failure.
1288  */
1289 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1290 {
1291         pthread_t gtp_thread;
1292         pthread_t ptg_thread;
1293         int err;
1294         int ret = 0;
1295         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1296                 &s->gtp);
1297         if (err)
1298                 die("Can't start thread for copying data: %s", strerror(err));
1299         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1300                 &s->ptg);
1301         if (err)
1302                 die("Can't start thread for copying data: %s", strerror(err));
1303
1304         ret |= tloop_join(gtp_thread, "Git to program copy");
1305         ret |= tloop_join(ptg_thread, "Program to git copy");
1306         return ret;
1307 }
1308 #else
1309
1310 /* Close the source and target (for writing) for transfer. */
1311 static void udt_kill_transfer(struct unidirectional_transfer *t)
1312 {
1313         t->state = SSTATE_FINISHED;
1314         /*
1315          * Socket read end left open isn't a disaster if nobody
1316          * attempts to read from it (mingw compat headers do not
1317          * have SHUT_RD)...
1318          *
1319          * We can't fully close the socket since otherwise gtp
1320          * task would first close the socket it sends data to
1321          * while closing the ptg file descriptors.
1322          */
1323         if (!t->src_is_sock)
1324                 close(t->src);
1325         if (t->dest_is_sock)
1326                 shutdown(t->dest, SHUT_WR);
1327         else
1328                 close(t->dest);
1329 }
1330
1331 /*
1332  * Join process, with appropriate errors on failure. Name is name for the
1333  * process (for error messages). Returns 0 on success, 1 on failure.
1334  */
1335 static int tloop_join(pid_t pid, const char *name)
1336 {
1337         int tret;
1338         if (waitpid(pid, &tret, 0) < 0) {
1339                 error_errno("%s process failed to wait", name);
1340                 return 1;
1341         }
1342         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1343                 error("%s process failed", name);
1344                 return 1;
1345         }
1346         return 0;
1347 }
1348
1349 /*
1350  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1351  * -1 on failure.
1352  */
1353 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1354 {
1355         pid_t pid1, pid2;
1356         int ret = 0;
1357
1358         /* Fork thread #1: git to program. */
1359         pid1 = fork();
1360         if (pid1 < 0)
1361                 die_errno("Can't start thread for copying data");
1362         else if (pid1 == 0) {
1363                 udt_kill_transfer(&s->ptg);
1364                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1365         }
1366
1367         /* Fork thread #2: program to git. */
1368         pid2 = fork();
1369         if (pid2 < 0)
1370                 die_errno("Can't start thread for copying data");
1371         else if (pid2 == 0) {
1372                 udt_kill_transfer(&s->gtp);
1373                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1374         }
1375
1376         /*
1377          * Close both streams in parent as to not interfere with
1378          * end of file detection and wait for both tasks to finish.
1379          */
1380         udt_kill_transfer(&s->gtp);
1381         udt_kill_transfer(&s->ptg);
1382         ret |= tloop_join(pid1, "Git to program copy");
1383         ret |= tloop_join(pid2, "Program to git copy");
1384         return ret;
1385 }
1386 #endif
1387
1388 /*
1389  * Copies data from stdin to output and from input to stdout simultaneously.
1390  * Additionally filtering through given filter. If filter is NULL, uses
1391  * identity filter.
1392  */
1393 int bidirectional_transfer_loop(int input, int output)
1394 {
1395         struct bidirectional_transfer_state state;
1396
1397         /* Fill the state fields. */
1398         state.ptg.src = input;
1399         state.ptg.dest = 1;
1400         state.ptg.src_is_sock = (input == output);
1401         state.ptg.dest_is_sock = 0;
1402         state.ptg.state = SSTATE_TRANSFERRING;
1403         state.ptg.bufuse = 0;
1404         state.ptg.src_name = "remote input";
1405         state.ptg.dest_name = "stdout";
1406
1407         state.gtp.src = 0;
1408         state.gtp.dest = output;
1409         state.gtp.src_is_sock = 0;
1410         state.gtp.dest_is_sock = (input == output);
1411         state.gtp.state = SSTATE_TRANSFERRING;
1412         state.gtp.bufuse = 0;
1413         state.gtp.src_name = "stdin";
1414         state.gtp.dest_name = "remote output";
1415
1416         return tloop_spawnwait_tasks(&state);
1417 }