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_item *refspecs;
  40         int refspec_nr;
  41         /* Transport options for fetch-pack/send-pack (should one of
  42          * those be invoked).
  43          */
  44         struct git_transport_options transport_options;
  45 };
  46
  47 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  48 {
  49         if (debug)
  50                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  51         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
  52                 die_errno("Full write to remote helper failed");
  53 }
  54
  55 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  56 {
  57         strbuf_reset(buffer);
  58         if (debug)
  59                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  60         if (strbuf_getline(buffer, helper) == EOF) {
  61                 if (debug)
  62                         fprintf(stderr, "Debug: Remote helper quit.\n");
  63                 return 1;
  64         }
  65
  66         if (debug)
  67                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  68         return 0;
  69 }
  70
  71 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  72 {
  73         return recvline_fh(helper->out, buffer);
  74 }
  75
  76 static void write_constant(int fd, const char *str)
  77 {
  78         if (debug)
  79                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  80         if (write_in_full(fd, str, strlen(str)) < 0)
  81                 die_errno("Full write to remote helper failed");
  82 }
  83
  84 static const char *remove_ext_force(const char *url)
  85 {
  86         if (url) {
  87                 const char *colon = strchr(url, ':');
  88                 if (colon && colon[1] == ':')
  89                         return colon + 2;
  90         }
  91         return url;
  92 }
  93
  94 static void do_take_over(struct transport *transport)
  95 {
  96         struct helper_data *data;
  97         data = (struct helper_data *)transport->data;
  98         transport_take_over(transport, data->helper);
  99         fclose(data->out);
 100         free(data);
 101 }
 102
 103 static void standard_options(struct transport *t);
 104
 105 static struct child_process *get_helper(struct transport *transport)
 106 {
 107         struct helper_data *data = transport->data;
 108         struct strbuf buf = STRBUF_INIT;
 109         struct child_process *helper;
 110         const char **refspecs = NULL;
 111         int refspec_nr = 0;
 112         int refspec_alloc = 0;
 113         int duped;
 114         int code;
 115
 116         if (data->helper)
 117                 return data->helper;
 118
 119         helper = xmalloc(sizeof(*helper));
 120         child_process_init(helper);
 121         helper->in = -1;
 122         helper->out = -1;
 123         helper->err = 0;
 124         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 125         argv_array_push(&helper->args, transport->remote->name);
 126         argv_array_push(&helper->args, remove_ext_force(transport->url));
 127         helper->git_cmd = 0;
 128         helper->silent_exec_failure = 1;
 129
 130         if (have_git_dir())
 131                 argv_array_pushf(&helper->env_array, "%s=%s",
 132                                  GIT_DIR_ENVIRONMENT, get_git_dir());
 133
 134         code = start_command(helper);
 135         if (code < 0 && errno == ENOENT)
 136                 die("Unable to find remote helper for '%s'", data->name);
 137         else if (code != 0)
 138                 exit(code);
 139
 140         data->helper = helper;
 141         data->no_disconnect_req = 0;
 142
 143         /*
 144          * Open the output as FILE* so strbuf_getline_*() family of
 145          * functions can be used.
 146          * Do this with duped fd because fclose() will close the fd,
 147          * and stuff like taking over will require the fd to remain.
 148          */
 149         duped = dup(helper->out);
 150         if (duped < 0)
 151                 die_errno("Can't dup helper output fd");
 152         data->out = xfdopen(duped, "r");
 153
 154         write_constant(helper->in, "capabilities\n");
 155
 156         while (1) {
 157                 const char *capname, *arg;
 158                 int mandatory = 0;
 159                 if (recvline(data, &buf))
 160                         exit(128);
 161
 162                 if (!*buf.buf)
 163                         break;
 164
 165                 if (*buf.buf == '*') {
 166                         capname = buf.buf + 1;
 167                         mandatory = 1;
 168                 } else
 169                         capname = buf.buf;
 170
 171                 if (debug)
 172                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 173                 if (!strcmp(capname, "fetch"))
 174                         data->fetch = 1;
 175                 else if (!strcmp(capname, "option"))
 176                         data->option = 1;
 177                 else if (!strcmp(capname, "push"))
 178                         data->push = 1;
 179                 else if (!strcmp(capname, "import"))
 180                         data->import = 1;
 181                 else if (!strcmp(capname, "bidi-import"))
 182                         data->bidi_import = 1;
 183                 else if (!strcmp(capname, "export"))
 184                         data->export = 1;
 185                 else if (!strcmp(capname, "check-connectivity"))
 186                         data->check_connectivity = 1;
 187                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 188                         ALLOC_GROW(refspecs,
 189                                    refspec_nr + 1,
 190                                    refspec_alloc);
 191                         refspecs[refspec_nr++] = xstrdup(arg);
 192                 } else if (!strcmp(capname, "connect")) {
 193                         data->connect = 1;
 194                 } else if (!strcmp(capname, "stateless-connect")) {
 195                         data->stateless_connect = 1;
 196                 } else if (!strcmp(capname, "signed-tags")) {
 197                         data->signed_tags = 1;
 198                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 199                         data->export_marks = xstrdup(arg);
 200                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 201                         data->import_marks = xstrdup(arg);
 202                 } else if (starts_with(capname, "no-private-update")) {
 203                         data->no_private_update = 1;
 204                 } else if (mandatory) {
 205                         die("Unknown mandatory capability %s. This remote "
 206                             "helper probably needs newer version of Git.",
 207                             capname);
 208                 }
 209         }
 210         if (refspecs) {
 211                 int i;
 212                 data->refspec_nr = refspec_nr;
 213                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 214                 for (i = 0; i < refspec_nr; i++)
 215                         free((char *)refspecs[i]);
 216                 free(refspecs);
 217         } else if (data->import || data->bidi_import || data->export) {
 218                 warning("This remote helper should implement refspec capability.");
 219         }
 220         strbuf_release(&buf);
 221         if (debug)
 222                 fprintf(stderr, "Debug: Capabilities complete.\n");
 223         standard_options(transport);
 224         return data->helper;
 225 }
 226
 227 static int disconnect_helper(struct transport *transport)
 228 {
 229         struct helper_data *data = transport->data;
 230         int res = 0;
 231
 232         if (data->helper) {
 233                 if (debug)
 234                         fprintf(stderr, "Debug: Disconnecting.\n");
 235                 if (!data->no_disconnect_req) {
 236                         /*
 237                          * Ignore write errors; there's nothing we can do,
 238                          * since we're about to close the pipe anyway. And the
 239                          * most likely error is EPIPE due to the helper dying
 240                          * to report an error itself.
 241                          */
 242                         sigchain_push(SIGPIPE, SIG_IGN);
 243                         xwrite(data->helper->in, "\n", 1);
 244                         sigchain_pop(SIGPIPE);
 245                 }
 246                 close(data->helper->in);
 247                 close(data->helper->out);
 248                 fclose(data->out);
 249                 res = finish_command(data->helper);
 250                 FREE_AND_NULL(data->helper);
 251         }
 252         return res;
 253 }
 254
 255 static const char *unsupported_options[] = {
 256         TRANS_OPT_UPLOADPACK,
 257         TRANS_OPT_RECEIVEPACK,
 258         TRANS_OPT_THIN,
 259         TRANS_OPT_KEEP
 260         };
 261
 262 static const char *boolean_options[] = {
 263         TRANS_OPT_THIN,
 264         TRANS_OPT_KEEP,
 265         TRANS_OPT_FOLLOWTAGS,
 266         TRANS_OPT_DEEPEN_RELATIVE
 267         };
 268
 269 static int strbuf_set_helper_option(struct helper_data *data,
 270                                     struct strbuf *buf)
 271 {
 272         int ret;
 273
 274         sendline(data, buf);
 275         if (recvline(data, buf))
 276                 exit(128);
 277
 278         if (!strcmp(buf->buf, "ok"))
 279                 ret = 0;
 280         else if (starts_with(buf->buf, "error"))
 281                 ret = -1;
 282         else if (!strcmp(buf->buf, "unsupported"))
 283                 ret = 1;
 284         else {
 285                 warning("%s unexpectedly said: '%s'", data->name, buf->buf);
 286                 ret = 1;
 287         }
 288         return ret;
 289 }
 290
 291 static int string_list_set_helper_option(struct helper_data *data,
 292                                          const char *name,
 293                                          struct string_list *list)
 294 {
 295         struct strbuf buf = STRBUF_INIT;
 296         int i, ret = 0;
 297
 298         for (i = 0; i < list->nr; i++) {
 299                 strbuf_addf(&buf, "option %s ", name);
 300                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 301                 strbuf_addch(&buf, '\n');
 302
 303                 if ((ret = strbuf_set_helper_option(data, &buf)))
 304                         break;
 305                 strbuf_reset(&buf);
 306         }
 307         strbuf_release(&buf);
 308         return ret;
 309 }
 310
 311 static int set_helper_option(struct transport *transport,
 312                           const char *name, const char *value)
 313 {
 314         struct helper_data *data = transport->data;
 315         struct strbuf buf = STRBUF_INIT;
 316         int i, ret, is_bool = 0;
 317
 318         get_helper(transport);
 319
 320         if (!data->option)
 321                 return 1;
 322
 323         if (!strcmp(name, "deepen-not"))
 324                 return string_list_set_helper_option(data, name,
 325                                                      (struct string_list *)value);
 326
 327         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 328                 if (!strcmp(name, unsupported_options[i]))
 329                         return 1;
 330         }
 331
 332         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 333                 if (!strcmp(name, boolean_options[i])) {
 334                         is_bool = 1;
 335                         break;
 336                 }
 337         }
 338
 339         strbuf_addf(&buf, "option %s ", name);
 340         if (is_bool)
 341                 strbuf_addstr(&buf, value ? "true" : "false");
 342         else
 343                 quote_c_style(value, &buf, NULL, 0);
 344         strbuf_addch(&buf, '\n');
 345
 346         ret = strbuf_set_helper_option(data, &buf);
 347         strbuf_release(&buf);
 348         return ret;
 349 }
 350
 351 static void standard_options(struct transport *t)
 352 {
 353         char buf[16];
 354         int v = t->verbose;
 355
 356         set_helper_option(t, "progress", t->progress ? "true" : "false");
 357
 358         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 359         set_helper_option(t, "verbosity", buf);
 360
 361         switch (t->family) {
 362         case TRANSPORT_FAMILY_ALL:
 363                 /*
 364                  * this is already the default,
 365                  * do not break old remote helpers by setting "all" here
 366                  */
 367                 break;
 368         case TRANSPORT_FAMILY_IPV4:
 369                 set_helper_option(t, "family", "ipv4");
 370                 break;
 371         case TRANSPORT_FAMILY_IPV6:
 372                 set_helper_option(t, "family", "ipv6");
 373                 break;
 374         }
 375 }
 376
 377 static int release_helper(struct transport *transport)
 378 {
 379         int res = 0;
 380         struct helper_data *data = transport->data;
 381         free_refspec(data->refspec_nr, data->refspecs);
 382         data->refspecs = NULL;
 383         res = disconnect_helper(transport);
 384         free(transport->data);
 385         return res;
 386 }
 387
 388 static int fetch_with_fetch(struct transport *transport,
 389                             int nr_heads, struct ref **to_fetch)
 390 {
 391         struct helper_data *data = transport->data;
 392         int i;
 393         struct strbuf buf = STRBUF_INIT;
 394
 395         for (i = 0; i < nr_heads; i++) {
 396                 const struct ref *posn = to_fetch[i];
 397                 if (posn->status & REF_STATUS_UPTODATE)
 398                         continue;
 399
 400                 strbuf_addf(&buf, "fetch %s %s\n",
 401                             oid_to_hex(&posn->old_oid),
 402                             posn->symref ? posn->symref : posn->name);
 403         }
 404
 405         strbuf_addch(&buf, '\n');
 406         sendline(data, &buf);
 407
 408         while (1) {
 409                 if (recvline(data, &buf))
 410                         exit(128);
 411
 412                 if (starts_with(buf.buf, "lock ")) {
 413                         const char *name = buf.buf + 5;
 414                         if (transport->pack_lockfile)
 415                                 warning("%s also locked %s", data->name, name);
 416                         else
 417                                 transport->pack_lockfile = xstrdup(name);
 418                 }
 419                 else if (data->check_connectivity &&
 420                          data->transport_options.check_self_contained_and_connected &&
 421                          !strcmp(buf.buf, "connectivity-ok"))
 422                         data->transport_options.self_contained_and_connected = 1;
 423                 else if (!buf.len)
 424                         break;
 425                 else
 426                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 427         }
 428         strbuf_release(&buf);
 429         return 0;
 430 }
 431
 432 static int get_importer(struct transport *transport, struct child_process *fastimport)
 433 {
 434         struct child_process *helper = get_helper(transport);
 435         struct helper_data *data = transport->data;
 436         int cat_blob_fd, code;
 437         child_process_init(fastimport);
 438         fastimport->in = helper->out;
 439         argv_array_push(&fastimport->args, "fast-import");
 440         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 441
 442         if (data->bidi_import) {
 443                 cat_blob_fd = xdup(helper->in);
 444                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 445         }
 446         fastimport->git_cmd = 1;
 447
 448         code = start_command(fastimport);
 449         return code;
 450 }
 451
 452 static int get_exporter(struct transport *transport,
 453                         struct child_process *fastexport,
 454                         struct string_list *revlist_args)
 455 {
 456         struct helper_data *data = transport->data;
 457         struct child_process *helper = get_helper(transport);
 458         int i;
 459
 460         child_process_init(fastexport);
 461
 462         /* we need to duplicate helper->in because we want to use it after
 463          * fastexport is done with it. */
 464         fastexport->out = dup(helper->in);
 465         argv_array_push(&fastexport->args, "fast-export");
 466         argv_array_push(&fastexport->args, "--use-done-feature");
 467         argv_array_push(&fastexport->args, data->signed_tags ?
 468                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 469         if (data->export_marks)
 470                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 471         if (data->import_marks)
 472                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 473
 474         for (i = 0; i < revlist_args->nr; i++)
 475                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 476
 477         fastexport->git_cmd = 1;
 478         return start_command(fastexport);
 479 }
 480
 481 static int fetch_with_import(struct transport *transport,
 482                              int nr_heads, struct ref **to_fetch)
 483 {
 484         struct child_process fastimport;
 485         struct helper_data *data = transport->data;
 486         int i;
 487         struct ref *posn;
 488         struct strbuf buf = STRBUF_INIT;
 489
 490         get_helper(transport);
 491
 492         if (get_importer(transport, &fastimport))
 493                 die("Couldn't run fast-import");
 494
 495         for (i = 0; i < nr_heads; i++) {
 496                 posn = to_fetch[i];
 497                 if (posn->status & REF_STATUS_UPTODATE)
 498                         continue;
 499
 500                 strbuf_addf(&buf, "import %s\n",
 501                             posn->symref ? posn->symref : posn->name);
 502                 sendline(data, &buf);
 503                 strbuf_reset(&buf);
 504         }
 505
 506         write_constant(data->helper->in, "\n");
 507         /*
 508          * remote-helpers that advertise the bidi-import capability are required to
 509          * buffer the complete batch of import commands until this newline before
 510          * sending data to fast-import.
 511          * These helpers read back data from fast-import on their stdin, which could
 512          * be mixed with import commands, otherwise.
 513          */
 514
 515         if (finish_command(&fastimport))
 516                 die("Error while running fast-import");
 517
 518         /*
 519          * The fast-import stream of a remote helper that advertises
 520          * the "refspec" capability writes to the refs named after the
 521          * right hand side of the first refspec matching each ref we
 522          * were fetching.
 523          *
 524          * (If no "refspec" capability was specified, for historical
 525          * reasons we default to the equivalent of *:*.)
 526          *
 527          * Store the result in to_fetch[i].old_sha1.  Callers such
 528          * as "git fetch" can use the value to write feedback to the
 529          * terminal, populate FETCH_HEAD, and determine what new value
 530          * should be written to peer_ref if the update is a
 531          * fast-forward or this is a forced update.
 532          */
 533         for (i = 0; i < nr_heads; i++) {
 534                 char *private, *name;
 535                 posn = to_fetch[i];
 536                 if (posn->status & REF_STATUS_UPTODATE)
 537                         continue;
 538                 name = posn->symref ? posn->symref : posn->name;
 539                 if (data->refspecs)
 540                         private = apply_refspecs(data->refspecs, data->refspec_nr, name);
 541                 else
 542                         private = xstrdup(name);
 543                 if (private) {
 544                         if (read_ref(private, &posn->old_oid) < 0)
 545                                 die("Could not read ref %s", private);
 546                         free(private);
 547                 }
 548         }
 549         strbuf_release(&buf);
 550         return 0;
 551 }
 552
 553 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 554 {
 555         struct helper_data *data = transport->data;
 556         int ret = 0;
 557         int duped;
 558         FILE *input;
 559         struct child_process *helper;
 560
 561         helper = get_helper(transport);
 562
 563         /*
 564          * Yes, dup the pipe another time, as we need unbuffered version
 565          * of input pipe as FILE*. fclose() closes the underlying fd and
 566          * stream buffering only can be changed before first I/O operation
 567          * on it.
 568          */
 569         duped = dup(helper->out);
 570         if (duped < 0)
 571                 die_errno("Can't dup helper output fd");
 572         input = xfdopen(duped, "r");
 573         setvbuf(input, NULL, _IONBF, 0);
 574
 575         sendline(data, cmdbuf);
 576         if (recvline_fh(input, cmdbuf))
 577                 exit(128);
 578
 579         if (!strcmp(cmdbuf->buf, "")) {
 580                 data->no_disconnect_req = 1;
 581                 if (debug)
 582                         fprintf(stderr, "Debug: Smart transport connection "
 583                                 "ready.\n");
 584                 ret = 1;
 585         } else if (!strcmp(cmdbuf->buf, "fallback")) {
 586                 if (debug)
 587                         fprintf(stderr, "Debug: Falling back to dumb "
 588                                 "transport.\n");
 589         } else {
 590                 die("Unknown response to connect: %s",
 591                         cmdbuf->buf);
 592         }
 593
 594         fclose(input);
 595         return ret;
 596 }
 597
 598 static int process_connect_service(struct transport *transport,
 599                                    const char *name, const char *exec)
 600 {
 601         struct helper_data *data = transport->data;
 602         struct strbuf cmdbuf = STRBUF_INIT;
 603         int ret = 0;
 604
 605         /*
 606          * Handle --upload-pack and friends. This is fire and forget...
 607          * just warn if it fails.
 608          */
 609         if (strcmp(name, exec)) {
 610                 int r = set_helper_option(transport, "servpath", exec);
 611                 if (r > 0)
 612                         warning("Setting remote service path not supported by protocol.");
 613                 else if (r < 0)
 614                         warning("Invalid remote service path.");
 615         }
 616
 617         if (data->connect) {
 618                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 619                 ret = run_connect(transport, &cmdbuf);
 620         } else if (data->stateless_connect &&
 621                    (get_protocol_version_config() == protocol_v2) &&
 622                    !strcmp("git-upload-pack", name)) {
 623                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 624                 ret = run_connect(transport, &cmdbuf);
 625                 if (ret)
 626                         transport->stateless_rpc = 1;
 627         }
 628
 629         strbuf_release(&cmdbuf);
 630         return ret;
 631 }
 632
 633 static int process_connect(struct transport *transport,
 634                                      int for_push)
 635 {
 636         struct helper_data *data = transport->data;
 637         const char *name;
 638         const char *exec;
 639
 640         name = for_push ? "git-receive-pack" : "git-upload-pack";
 641         if (for_push)
 642                 exec = data->transport_options.receivepack;
 643         else
 644                 exec = data->transport_options.uploadpack;
 645
 646         return process_connect_service(transport, name, exec);
 647 }
 648
 649 static int connect_helper(struct transport *transport, const char *name,
 650                    const char *exec, int fd[2])
 651 {
 652         struct helper_data *data = transport->data;
 653
 654         /* Get_helper so connect is inited. */
 655         get_helper(transport);
 656         if (!data->connect)
 657                 die("Operation not supported by protocol.");
 658
 659         if (!process_connect_service(transport, name, exec))
 660                 die("Can't connect to subservice %s.", name);
 661
 662         fd[0] = data->helper->out;
 663         fd[1] = data->helper->in;
 664         return 0;
 665 }
 666
 667 static int fetch(struct transport *transport,
 668                  int nr_heads, struct ref **to_fetch)
 669 {
 670         struct helper_data *data = transport->data;
 671         int i, count;
 672
 673         if (process_connect(transport, 0)) {
 674                 do_take_over(transport);
 675                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
 676         }
 677
 678         count = 0;
 679         for (i = 0; i < nr_heads; i++)
 680                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 681                         count++;
 682
 683         if (!count)
 684                 return 0;
 685
 686         if (data->check_connectivity &&
 687             data->transport_options.check_self_contained_and_connected)
 688                 set_helper_option(transport, "check-connectivity", "true");
 689
 690         if (transport->cloning)
 691                 set_helper_option(transport, "cloning", "true");
 692
 693         if (data->transport_options.update_shallow)
 694                 set_helper_option(transport, "update-shallow", "true");
 695
 696         if (data->transport_options.filter_options.choice)
 697                 set_helper_option(
 698                         transport, "filter",
 699                         data->transport_options.filter_options.filter_spec);
 700
 701         if (data->fetch)
 702                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 703
 704         if (data->import)
 705                 return fetch_with_import(transport, nr_heads, to_fetch);
 706
 707         return -1;
 708 }
 709
 710 static int push_update_ref_status(struct strbuf *buf,
 711                                    struct ref **ref,
 712                                    struct ref *remote_refs)
 713 {
 714         char *refname, *msg;
 715         int status, forced = 0;
 716
 717         if (starts_with(buf->buf, "ok ")) {
 718                 status = REF_STATUS_OK;
 719                 refname = buf->buf + 3;
 720         } else if (starts_with(buf->buf, "error ")) {
 721                 status = REF_STATUS_REMOTE_REJECT;
 722                 refname = buf->buf + 6;
 723         } else
 724                 die("expected ok/error, helper said '%s'", buf->buf);
 725
 726         msg = strchr(refname, ' ');
 727         if (msg) {
 728                 struct strbuf msg_buf = STRBUF_INIT;
 729                 const char *end;
 730
 731                 *msg++ = '\0';
 732                 if (!unquote_c_style(&msg_buf, msg, &end))
 733                         msg = strbuf_detach(&msg_buf, NULL);
 734                 else
 735                         msg = xstrdup(msg);
 736                 strbuf_release(&msg_buf);
 737
 738                 if (!strcmp(msg, "no match")) {
 739                         status = REF_STATUS_NONE;
 740                         FREE_AND_NULL(msg);
 741                 }
 742                 else if (!strcmp(msg, "up to date")) {
 743                         status = REF_STATUS_UPTODATE;
 744                         FREE_AND_NULL(msg);
 745                 }
 746                 else if (!strcmp(msg, "non-fast forward")) {
 747                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 748                         FREE_AND_NULL(msg);
 749                 }
 750                 else if (!strcmp(msg, "already exists")) {
 751                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 752                         FREE_AND_NULL(msg);
 753                 }
 754                 else if (!strcmp(msg, "fetch first")) {
 755                         status = REF_STATUS_REJECT_FETCH_FIRST;
 756                         FREE_AND_NULL(msg);
 757                 }
 758                 else if (!strcmp(msg, "needs force")) {
 759                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 760                         FREE_AND_NULL(msg);
 761                 }
 762                 else if (!strcmp(msg, "stale info")) {
 763                         status = REF_STATUS_REJECT_STALE;
 764                         FREE_AND_NULL(msg);
 765                 }
 766                 else if (!strcmp(msg, "forced update")) {
 767                         forced = 1;
 768                         FREE_AND_NULL(msg);
 769                 }
 770         }
 771
 772         if (*ref)
 773                 *ref = find_ref_by_name(*ref, refname);
 774         if (!*ref)
 775                 *ref = find_ref_by_name(remote_refs, refname);
 776         if (!*ref) {
 777                 warning("helper reported unexpected status of %s", refname);
 778                 return 1;
 779         }
 780
 781         if ((*ref)->status != REF_STATUS_NONE) {
 782                 /*
 783                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 784                  * status reported by the remote helper if the latter is 'no match'.
 785                  */
 786                 if (status == REF_STATUS_NONE)
 787                         return 1;
 788         }
 789
 790         (*ref)->status = status;
 791         (*ref)->forced_update |= forced;
 792         (*ref)->remote_status = msg;
 793         return !(status == REF_STATUS_OK);
 794 }
 795
 796 static int push_update_refs_status(struct helper_data *data,
 797                                     struct ref *remote_refs,
 798                                     int flags)
 799 {
 800         struct strbuf buf = STRBUF_INIT;
 801         struct ref *ref = remote_refs;
 802         int ret = 0;
 803
 804         for (;;) {
 805                 char *private;
 806
 807                 if (recvline(data, &buf)) {
 808                         ret = 1;
 809                         break;
 810                 }
 811
 812                 if (!buf.len)
 813                         break;
 814
 815                 if (push_update_ref_status(&buf, &ref, remote_refs))
 816                         continue;
 817
 818                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 819                         continue;
 820
 821                 /* propagate back the update to the remote namespace */
 822                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 823                 if (!private)
 824                         continue;
 825                 update_ref("update by helper", private, &ref->new_oid, NULL,
 826                            0, 0);
 827                 free(private);
 828         }
 829         strbuf_release(&buf);
 830         return ret;
 831 }
 832
 833 static void set_common_push_options(struct transport *transport,
 834                                    const char *name, int flags)
 835 {
 836         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 837                 if (set_helper_option(transport, "dry-run", "true") != 0)
 838                         die("helper %s does not support dry-run", name);
 839         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 840                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 841                         die("helper %s does not support --signed", name);
 842         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 843                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 844                         die("helper %s does not support --signed=if-asked", name);
 845         }
 846
 847         if (flags & TRANSPORT_PUSH_OPTIONS) {
 848                 struct string_list_item *item;
 849                 for_each_string_list_item(item, transport->push_options)
 850                         if (set_helper_option(transport, "push-option", item->string) != 0)
 851                                 die("helper %s does not support 'push-option'", name);
 852         }
 853 }
 854
 855 static int push_refs_with_push(struct transport *transport,
 856                                struct ref *remote_refs, int flags)
 857 {
 858         int force_all = flags & TRANSPORT_PUSH_FORCE;
 859         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 860         struct helper_data *data = transport->data;
 861         struct strbuf buf = STRBUF_INIT;
 862         struct ref *ref;
 863         struct string_list cas_options = STRING_LIST_INIT_DUP;
 864         struct string_list_item *cas_option;
 865
 866         get_helper(transport);
 867         if (!data->push)
 868                 return 1;
 869
 870         for (ref = remote_refs; ref; ref = ref->next) {
 871                 if (!ref->peer_ref && !mirror)
 872                         continue;
 873
 874                 /* Check for statuses set by set_ref_status_for_push() */
 875                 switch (ref->status) {
 876                 case REF_STATUS_REJECT_NONFASTFORWARD:
 877                 case REF_STATUS_REJECT_STALE:
 878                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 879                 case REF_STATUS_UPTODATE:
 880                         continue;
 881                 default:
 882                         ; /* do nothing */
 883                 }
 884
 885                 if (force_all)
 886                         ref->force = 1;
 887
 888                 strbuf_addstr(&buf, "push ");
 889                 if (!ref->deletion) {
 890                         if (ref->force)
 891                                 strbuf_addch(&buf, '+');
 892                         if (ref->peer_ref)
 893                                 strbuf_addstr(&buf, ref->peer_ref->name);
 894                         else
 895                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
 896                 }
 897                 strbuf_addch(&buf, ':');
 898                 strbuf_addstr(&buf, ref->name);
 899                 strbuf_addch(&buf, '\n');
 900
 901                 /*
 902                  * The "--force-with-lease" options without explicit
 903                  * values to expect have already been expanded into
 904                  * the ref->old_oid_expect[] field; we can ignore
 905                  * transport->smart_options->cas altogether and instead
 906                  * can enumerate them from the refs.
 907                  */
 908                 if (ref->expect_old_sha1) {
 909                         struct strbuf cas = STRBUF_INIT;
 910                         strbuf_addf(&cas, "%s:%s",
 911                                     ref->name, oid_to_hex(&ref->old_oid_expect));
 912                         string_list_append_nodup(&cas_options,
 913                                                  strbuf_detach(&cas, NULL));
 914                 }
 915         }
 916         if (buf.len == 0) {
 917                 string_list_clear(&cas_options, 0);
 918                 return 0;
 919         }
 920
 921         for_each_string_list_item(cas_option, &cas_options)
 922                 set_helper_option(transport, "cas", cas_option->string);
 923         set_common_push_options(transport, data->name, flags);
 924
 925         strbuf_addch(&buf, '\n');
 926         sendline(data, &buf);
 927         strbuf_release(&buf);
 928         string_list_clear(&cas_options, 0);
 929
 930         return push_update_refs_status(data, remote_refs, flags);
 931 }
 932
 933 static int push_refs_with_export(struct transport *transport,
 934                 struct ref *remote_refs, int flags)
 935 {
 936         struct ref *ref;
 937         struct child_process *helper, exporter;
 938         struct helper_data *data = transport->data;
 939         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 940         struct strbuf buf = STRBUF_INIT;
 941
 942         if (!data->refspecs)
 943                 die("remote-helper doesn't support push; refspec needed");
 944
 945         set_common_push_options(transport, data->name, flags);
 946         if (flags & TRANSPORT_PUSH_FORCE) {
 947                 if (set_helper_option(transport, "force", "true") != 0)
 948                         warning("helper %s does not support 'force'", data->name);
 949         }
 950
 951         helper = get_helper(transport);
 952
 953         write_constant(helper->in, "export\n");
 954
 955         for (ref = remote_refs; ref; ref = ref->next) {
 956                 char *private;
 957                 struct object_id oid;
 958
 959                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 960                 if (private && !get_oid(private, &oid)) {
 961                         strbuf_addf(&buf, "^%s", private);
 962                         string_list_append_nodup(&revlist_args,
 963                                                  strbuf_detach(&buf, NULL));
 964                         oidcpy(&ref->old_oid, &oid);
 965                 }
 966                 free(private);
 967
 968                 if (ref->peer_ref) {
 969                         if (strcmp(ref->name, ref->peer_ref->name)) {
 970                                 if (!ref->deletion) {
 971                                         const char *name;
 972                                         int flag;
 973
 974                                         /* Follow symbolic refs (mainly for HEAD). */
 975                                         name = resolve_ref_unsafe(ref->peer_ref->name,
 976                                                                   RESOLVE_REF_READING,
 977                                                                   &oid, &flag);
 978                                         if (!name || !(flag & REF_ISSYMREF))
 979                                                 name = ref->peer_ref->name;
 980
 981                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 982                                 } else
 983                                         strbuf_addf(&buf, ":%s", ref->name);
 984
 985                                 string_list_append(&revlist_args, "--refspec");
 986                                 string_list_append(&revlist_args, buf.buf);
 987                                 strbuf_release(&buf);
 988                         }
 989                         if (!ref->deletion)
 990                                 string_list_append(&revlist_args, ref->peer_ref->name);
 991                 }
 992         }
 993
 994         if (get_exporter(transport, &exporter, &revlist_args))
 995                 die("Couldn't run fast-export");
 996
 997         string_list_clear(&revlist_args, 1);
 998
 999         if (finish_command(&exporter))
1000                 die("Error while running fast-export");
1001         if (push_update_refs_status(data, remote_refs, flags))
1002                 return 1;
1003
1004         if (data->export_marks) {
1005                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
1006                 rename(buf.buf, data->export_marks);
1007                 strbuf_release(&buf);
1008         }
1009
1010         return 0;
1011 }
1012
1013 static int push_refs(struct transport *transport,
1014                 struct ref *remote_refs, int flags)
1015 {
1016         struct helper_data *data = transport->data;
1017
1018         if (process_connect(transport, 1)) {
1019                 do_take_over(transport);
1020                 return transport->vtable->push_refs(transport, remote_refs, flags);
1021         }
1022
1023         if (!remote_refs) {
1024                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
1025                         "Perhaps you should specify a branch such as 'master'.\n");
1026                 return 0;
1027         }
1028
1029         if (data->push)
1030                 return push_refs_with_push(transport, remote_refs, flags);
1031
1032         if (data->export)
1033                 return push_refs_with_export(transport, remote_refs, flags);
1034
1035         return -1;
1036 }
1037
1038
1039 static int has_attribute(const char *attrs, const char *attr) {
1040         int len;
1041         if (!attrs)
1042                 return 0;
1043
1044         len = strlen(attr);
1045         for (;;) {
1046                 const char *space = strchrnul(attrs, ' ');
1047                 if (len == space - attrs && !strncmp(attrs, attr, len))
1048                         return 1;
1049                 if (!*space)
1050                         return 0;
1051                 attrs = space + 1;
1052         }
1053 }
1054
1055 static struct ref *get_refs_list(struct transport *transport, int for_push,
1056                                  const struct argv_array *ref_prefixes)
1057 {
1058         struct helper_data *data = transport->data;
1059         struct child_process *helper;
1060         struct ref *ret = NULL;
1061         struct ref **tail = &ret;
1062         struct ref *posn;
1063         struct strbuf buf = STRBUF_INIT;
1064
1065         helper = get_helper(transport);
1066
1067         if (process_connect(transport, for_push)) {
1068                 do_take_over(transport);
1069                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1070         }
1071
1072         if (data->push && for_push)
1073                 write_str_in_full(helper->in, "list for-push\n");
1074         else
1075                 write_str_in_full(helper->in, "list\n");
1076
1077         while (1) {
1078                 char *eov, *eon;
1079                 if (recvline(data, &buf))
1080                         exit(128);
1081
1082                 if (!*buf.buf)
1083                         break;
1084
1085                 eov = strchr(buf.buf, ' ');
1086                 if (!eov)
1087                         die("Malformed response in ref list: %s", buf.buf);
1088                 eon = strchr(eov + 1, ' ');
1089                 *eov = '\0';
1090                 if (eon)
1091                         *eon = '\0';
1092                 *tail = alloc_ref(eov + 1);
1093                 if (buf.buf[0] == '@')
1094                         (*tail)->symref = xstrdup(buf.buf + 1);
1095                 else if (buf.buf[0] != '?')
1096                         get_oid_hex(buf.buf, &(*tail)->old_oid);
1097                 if (eon) {
1098                         if (has_attribute(eon + 1, "unchanged")) {
1099                                 (*tail)->status |= REF_STATUS_UPTODATE;
1100                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1101                                         die(_("Could not read ref %s"),
1102                                             (*tail)->name);
1103                         }
1104                 }
1105                 tail = &((*tail)->next);
1106         }
1107         if (debug)
1108                 fprintf(stderr, "Debug: Read ref listing.\n");
1109         strbuf_release(&buf);
1110
1111         for (posn = ret; posn; posn = posn->next)
1112                 resolve_remote_symref(posn, ret);
1113
1114         return ret;
1115 }
1116
1117 static struct transport_vtable vtable = {
1118         set_helper_option,
1119         get_refs_list,
1120         fetch,
1121         push_refs,
1122         connect_helper,
1123         release_helper
1124 };
1125
1126 int transport_helper_init(struct transport *transport, const char *name)
1127 {
1128         struct helper_data *data = xcalloc(1, sizeof(*data));
1129         data->name = name;
1130
1131         transport_check_allowed(name);
1132
1133         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1134                 debug = 1;
1135
1136         transport->data = data;
1137         transport->vtable = &vtable;
1138         transport->smart_options = &(data->transport_options);
1139         return 0;
1140 }
1141
1142 /*
1143  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1144  * buffer less), so attempt reads and writes with up to that size.
1145  */
1146 #define BUFFERSIZE 65536
1147 /* This should be enough to hold debugging message. */
1148 #define PBUFFERSIZE 8192
1149
1150 /* Print bidirectional transfer loop debug message. */
1151 __attribute__((format (printf, 1, 2)))
1152 static void transfer_debug(const char *fmt, ...)
1153 {
1154         /*
1155          * NEEDSWORK: This function is sometimes used from multiple threads, and
1156          * we end up using debug_enabled racily. That "should not matter" since
1157          * we always write the same value, but it's still wrong. This function
1158          * is listed in .tsan-suppressions for the time being.
1159          */
1160
1161         va_list args;
1162         char msgbuf[PBUFFERSIZE];
1163         static int debug_enabled = -1;
1164
1165         if (debug_enabled < 0)
1166                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1167         if (!debug_enabled)
1168                 return;
1169
1170         va_start(args, fmt);
1171         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1172         va_end(args);
1173         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1174 }
1175
1176 /* Stream state: More data may be coming in this direction. */
1177 #define SSTATE_TRANSFERRING 0
1178 /*
1179  * Stream state: No more data coming in this direction, flushing rest of
1180  * data.
1181  */
1182 #define SSTATE_FLUSHING 1
1183 /* Stream state: Transfer in this direction finished. */
1184 #define SSTATE_FINISHED 2
1185
1186 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1187 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1188 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1189
1190 /* Unidirectional transfer. */
1191 struct unidirectional_transfer {
1192         /* Source */
1193         int src;
1194         /* Destination */
1195         int dest;
1196         /* Is source socket? */
1197         int src_is_sock;
1198         /* Is destination socket? */
1199         int dest_is_sock;
1200         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1201         int state;
1202         /* Buffer. */
1203         char buf[BUFFERSIZE];
1204         /* Buffer used. */
1205         size_t bufuse;
1206         /* Name of source. */
1207         const char *src_name;
1208         /* Name of destination. */
1209         const char *dest_name;
1210 };
1211
1212 /* Closes the target (for writing) if transfer has finished. */
1213 static void udt_close_if_finished(struct unidirectional_transfer *t)
1214 {
1215         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1216                 t->state = SSTATE_FINISHED;
1217                 if (t->dest_is_sock)
1218                         shutdown(t->dest, SHUT_WR);
1219                 else
1220                         close(t->dest);
1221                 transfer_debug("Closed %s.", t->dest_name);
1222         }
1223 }
1224
1225 /*
1226  * Tries to read data from source into buffer. If buffer is full,
1227  * no data is read. Returns 0 on success, -1 on error.
1228  */
1229 static int udt_do_read(struct unidirectional_transfer *t)
1230 {
1231         ssize_t bytes;
1232
1233         if (t->bufuse == BUFFERSIZE)
1234                 return 0;       /* No space for more. */
1235
1236         transfer_debug("%s is readable", t->src_name);
1237         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1238         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1239                 errno != EINTR) {
1240                 error_errno("read(%s) failed", t->src_name);
1241                 return -1;
1242         } else if (bytes == 0) {
1243                 transfer_debug("%s EOF (with %i bytes in buffer)",
1244                         t->src_name, (int)t->bufuse);
1245                 t->state = SSTATE_FLUSHING;
1246         } else if (bytes > 0) {
1247                 t->bufuse += bytes;
1248                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1249                         (int)bytes, t->src_name, (int)t->bufuse);
1250         }
1251         return 0;
1252 }
1253
1254 /* Tries to write data from buffer into destination. If buffer is empty,
1255  * no data is written. Returns 0 on success, -1 on error.
1256  */
1257 static int udt_do_write(struct unidirectional_transfer *t)
1258 {
1259         ssize_t bytes;
1260
1261         if (t->bufuse == 0)
1262                 return 0;       /* Nothing to write. */
1263
1264         transfer_debug("%s is writable", t->dest_name);
1265         bytes = xwrite(t->dest, t->buf, t->bufuse);
1266         if (bytes < 0 && errno != EWOULDBLOCK) {
1267                 error_errno("write(%s) failed", t->dest_name);
1268                 return -1;
1269         } else if (bytes > 0) {
1270                 t->bufuse -= bytes;
1271                 if (t->bufuse)
1272                         memmove(t->buf, t->buf + bytes, t->bufuse);
1273                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1274                         (int)bytes, t->dest_name, (int)t->bufuse);
1275         }
1276         return 0;
1277 }
1278
1279
1280 /* State of bidirectional transfer loop. */
1281 struct bidirectional_transfer_state {
1282         /* Direction from program to git. */
1283         struct unidirectional_transfer ptg;
1284         /* Direction from git to program. */
1285         struct unidirectional_transfer gtp;
1286 };
1287
1288 static void *udt_copy_task_routine(void *udt)
1289 {
1290         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1291         while (t->state != SSTATE_FINISHED) {
1292                 if (STATE_NEEDS_READING(t->state))
1293                         if (udt_do_read(t))
1294                                 return NULL;
1295                 if (STATE_NEEDS_WRITING(t->state))
1296                         if (udt_do_write(t))
1297                                 return NULL;
1298                 if (STATE_NEEDS_CLOSING(t->state))
1299                         udt_close_if_finished(t);
1300         }
1301         return udt;     /* Just some non-NULL value. */
1302 }
1303
1304 #ifndef NO_PTHREADS
1305
1306 /*
1307  * Join thread, with appropriate errors on failure. Name is name for the
1308  * thread (for error messages). Returns 0 on success, 1 on failure.
1309  */
1310 static int tloop_join(pthread_t thread, const char *name)
1311 {
1312         int err;
1313         void *tret;
1314         err = pthread_join(thread, &tret);
1315         if (!tret) {
1316                 error("%s thread failed", name);
1317                 return 1;
1318         }
1319         if (err) {
1320                 error("%s thread failed to join: %s", name, strerror(err));
1321                 return 1;
1322         }
1323         return 0;
1324 }
1325
1326 /*
1327  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1328  * -1 on failure.
1329  */
1330 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1331 {
1332         pthread_t gtp_thread;
1333         pthread_t ptg_thread;
1334         int err;
1335         int ret = 0;
1336         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1337                 &s->gtp);
1338         if (err)
1339                 die("Can't start thread for copying data: %s", strerror(err));
1340         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1341                 &s->ptg);
1342         if (err)
1343                 die("Can't start thread for copying data: %s", strerror(err));
1344
1345         ret |= tloop_join(gtp_thread, "Git to program copy");
1346         ret |= tloop_join(ptg_thread, "Program to git copy");
1347         return ret;
1348 }
1349 #else
1350
1351 /* Close the source and target (for writing) for transfer. */
1352 static void udt_kill_transfer(struct unidirectional_transfer *t)
1353 {
1354         t->state = SSTATE_FINISHED;
1355         /*
1356          * Socket read end left open isn't a disaster if nobody
1357          * attempts to read from it (mingw compat headers do not
1358          * have SHUT_RD)...
1359          *
1360          * We can't fully close the socket since otherwise gtp
1361          * task would first close the socket it sends data to
1362          * while closing the ptg file descriptors.
1363          */
1364         if (!t->src_is_sock)
1365                 close(t->src);
1366         if (t->dest_is_sock)
1367                 shutdown(t->dest, SHUT_WR);
1368         else
1369                 close(t->dest);
1370 }
1371
1372 /*
1373  * Join process, with appropriate errors on failure. Name is name for the
1374  * process (for error messages). Returns 0 on success, 1 on failure.
1375  */
1376 static int tloop_join(pid_t pid, const char *name)
1377 {
1378         int tret;
1379         if (waitpid(pid, &tret, 0) < 0) {
1380                 error_errno("%s process failed to wait", name);
1381                 return 1;
1382         }
1383         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1384                 error("%s process failed", name);
1385                 return 1;
1386         }
1387         return 0;
1388 }
1389
1390 /*
1391  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1392  * -1 on failure.
1393  */
1394 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1395 {
1396         pid_t pid1, pid2;
1397         int ret = 0;
1398
1399         /* Fork thread #1: git to program. */
1400         pid1 = fork();
1401         if (pid1 < 0)
1402                 die_errno("Can't start thread for copying data");
1403         else if (pid1 == 0) {
1404                 udt_kill_transfer(&s->ptg);
1405                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1406         }
1407
1408         /* Fork thread #2: program to git. */
1409         pid2 = fork();
1410         if (pid2 < 0)
1411                 die_errno("Can't start thread for copying data");
1412         else if (pid2 == 0) {
1413                 udt_kill_transfer(&s->gtp);
1414                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1415         }
1416
1417         /*
1418          * Close both streams in parent as to not interfere with
1419          * end of file detection and wait for both tasks to finish.
1420          */
1421         udt_kill_transfer(&s->gtp);
1422         udt_kill_transfer(&s->ptg);
1423         ret |= tloop_join(pid1, "Git to program copy");
1424         ret |= tloop_join(pid2, "Program to git copy");
1425         return ret;
1426 }
1427 #endif
1428
1429 /*
1430  * Copies data from stdin to output and from input to stdout simultaneously.
1431  * Additionally filtering through given filter. If filter is NULL, uses
1432  * identity filter.
1433  */
1434 int bidirectional_transfer_loop(int input, int output)
1435 {
1436         struct bidirectional_transfer_state state;
1437
1438         /* Fill the state fields. */
1439         state.ptg.src = input;
1440         state.ptg.dest = 1;
1441         state.ptg.src_is_sock = (input == output);
1442         state.ptg.dest_is_sock = 0;
1443         state.ptg.state = SSTATE_TRANSFERRING;
1444         state.ptg.bufuse = 0;
1445         state.ptg.src_name = "remote input";
1446         state.ptg.dest_name = "stdout";
1447
1448         state.gtp.src = 0;
1449         state.gtp.dest = output;
1450         state.gtp.src_is_sock = 0;
1451         state.gtp.dest_is_sock = (input == output);
1452         state.gtp.state = SSTATE_TRANSFERRING;
1453         state.gtp.bufuse = 0;
1454         state.gtp.src_name = "stdin";
1455         state.gtp.dest_name = "remote output";
1456
1457         return tloop_spawnwait_tasks(&state);
1458 }