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 "strvec.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                 object_format : 1;
  37
  38         /*
  39          * As an optimization, the transport code may invoke fetch before
  40          * get_refs_list. If this happens, and if the transport helper doesn't
  41          * support connect or stateless_connect, we need to invoke
  42          * get_refs_list ourselves if we haven't already done so. Keep track of
  43          * whether we have invoked get_refs_list.
  44          */
  45         unsigned get_refs_list_called : 1;
  46
  47         char *export_marks;
  48         char *import_marks;
  49         /* These go from remote name (as in "list") to private name */
  50         struct refspec rs;
  51         /* Transport options for fetch-pack/send-pack (should one of
  52          * those be invoked).
  53          */
  54         struct git_transport_options transport_options;
  55 };
  56
  57 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  58 {
  59         if (debug)
  60                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  61         if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
  62                 die_errno(_("full write to remote helper failed"));
  63 }
  64
  65 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  66 {
  67         strbuf_reset(buffer);
  68         if (debug)
  69                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  70         if (strbuf_getline(buffer, helper) == EOF) {
  71                 if (debug)
  72                         fprintf(stderr, "Debug: Remote helper quit.\n");
  73                 return 1;
  74         }
  75
  76         if (debug)
  77                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  78         return 0;
  79 }
  80
  81 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  82 {
  83         return recvline_fh(helper->out, buffer);
  84 }
  85
  86 static void write_constant(int fd, const char *str)
  87 {
  88         if (debug)
  89                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  90         if (write_in_full(fd, str, strlen(str)) < 0)
  91                 die_errno(_("full write to remote helper failed"));
  92 }
  93
  94 static const char *remove_ext_force(const char *url)
  95 {
  96         if (url) {
  97                 const char *colon = strchr(url, ':');
  98                 if (colon && colon[1] == ':')
  99                         return colon + 2;
 100         }
 101         return url;
 102 }
 103
 104 static void do_take_over(struct transport *transport)
 105 {
 106         struct helper_data *data;
 107         data = (struct helper_data *)transport->data;
 108         transport_take_over(transport, data->helper);
 109         fclose(data->out);
 110         free(data);
 111 }
 112
 113 static void standard_options(struct transport *t);
 114
 115 static struct child_process *get_helper(struct transport *transport)
 116 {
 117         struct helper_data *data = transport->data;
 118         struct strbuf buf = STRBUF_INIT;
 119         struct child_process *helper;
 120         int duped;
 121         int code;
 122
 123         if (data->helper)
 124                 return data->helper;
 125
 126         helper = xmalloc(sizeof(*helper));
 127         child_process_init(helper);
 128         helper->in = -1;
 129         helper->out = -1;
 130         helper->err = 0;
 131         strvec_pushf(&helper->args, "remote-%s", data->name);
 132         strvec_push(&helper->args, transport->remote->name);
 133         strvec_push(&helper->args, remove_ext_force(transport->url));
 134         helper->git_cmd = 1;
 135         helper->silent_exec_failure = 1;
 136
 137         if (have_git_dir())
 138                 strvec_pushf(&helper->env_array, "%s=%s",
 139                              GIT_DIR_ENVIRONMENT, get_git_dir());
 140
 141         helper->trace2_child_class = helper->args.v[0]; /* "remote-<name>" */
 142
 143         code = start_command(helper);
 144         if (code < 0 && errno == ENOENT)
 145                 die(_("unable to find remote helper for '%s'"), data->name);
 146         else if (code != 0)
 147                 exit(code);
 148
 149         data->helper = helper;
 150         data->no_disconnect_req = 0;
 151         refspec_init(&data->rs, REFSPEC_FETCH);
 152
 153         /*
 154          * Open the output as FILE* so strbuf_getline_*() family of
 155          * functions can be used.
 156          * Do this with duped fd because fclose() will close the fd,
 157          * and stuff like taking over will require the fd to remain.
 158          */
 159         duped = dup(helper->out);
 160         if (duped < 0)
 161                 die_errno(_("can't dup helper output fd"));
 162         data->out = xfdopen(duped, "r");
 163
 164         write_constant(helper->in, "capabilities\n");
 165
 166         while (1) {
 167                 const char *capname, *arg;
 168                 int mandatory = 0;
 169                 if (recvline(data, &buf))
 170                         exit(128);
 171
 172                 if (!*buf.buf)
 173                         break;
 174
 175                 if (*buf.buf == '*') {
 176                         capname = buf.buf + 1;
 177                         mandatory = 1;
 178                 } else
 179                         capname = buf.buf;
 180
 181                 if (debug)
 182                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 183                 if (!strcmp(capname, "fetch"))
 184                         data->fetch = 1;
 185                 else if (!strcmp(capname, "option"))
 186                         data->option = 1;
 187                 else if (!strcmp(capname, "push"))
 188                         data->push = 1;
 189                 else if (!strcmp(capname, "import"))
 190                         data->import = 1;
 191                 else if (!strcmp(capname, "bidi-import"))
 192                         data->bidi_import = 1;
 193                 else if (!strcmp(capname, "export"))
 194                         data->export = 1;
 195                 else if (!strcmp(capname, "check-connectivity"))
 196                         data->check_connectivity = 1;
 197                 else if (skip_prefix(capname, "refspec ", &arg)) {
 198                         refspec_append(&data->rs, arg);
 199                 } else if (!strcmp(capname, "connect")) {
 200                         data->connect = 1;
 201                 } else if (!strcmp(capname, "stateless-connect")) {
 202                         data->stateless_connect = 1;
 203                 } else if (!strcmp(capname, "signed-tags")) {
 204                         data->signed_tags = 1;
 205                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 206                         data->export_marks = xstrdup(arg);
 207                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 208                         data->import_marks = xstrdup(arg);
 209                 } else if (starts_with(capname, "no-private-update")) {
 210                         data->no_private_update = 1;
 211                 } else if (starts_with(capname, "object-format")) {
 212                         data->object_format = 1;
 213                 } else if (mandatory) {
 214                         die(_("unknown mandatory capability %s; this remote "
 215                               "helper probably needs newer version of Git"),
 216                             capname);
 217                 }
 218         }
 219         if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
 220                 warning(_("this remote helper should implement refspec capability"));
 221         }
 222         strbuf_release(&buf);
 223         if (debug)
 224                 fprintf(stderr, "Debug: Capabilities complete.\n");
 225         standard_options(transport);
 226         return data->helper;
 227 }
 228
 229 static int disconnect_helper(struct transport *transport)
 230 {
 231         struct helper_data *data = transport->data;
 232         int res = 0;
 233
 234         if (data->helper) {
 235                 if (debug)
 236                         fprintf(stderr, "Debug: Disconnecting.\n");
 237                 if (!data->no_disconnect_req) {
 238                         /*
 239                          * Ignore write errors; there's nothing we can do,
 240                          * since we're about to close the pipe anyway. And the
 241                          * most likely error is EPIPE due to the helper dying
 242                          * to report an error itself.
 243                          */
 244                         sigchain_push(SIGPIPE, SIG_IGN);
 245                         xwrite(data->helper->in, "\n", 1);
 246                         sigchain_pop(SIGPIPE);
 247                 }
 248                 close(data->helper->in);
 249                 close(data->helper->out);
 250                 fclose(data->out);
 251                 res = finish_command(data->helper);
 252                 FREE_AND_NULL(data->helper);
 253         }
 254         return res;
 255 }
 256
 257 static const char *unsupported_options[] = {
 258         TRANS_OPT_UPLOADPACK,
 259         TRANS_OPT_RECEIVEPACK,
 260         TRANS_OPT_THIN,
 261         TRANS_OPT_KEEP
 262         };
 263
 264 static const char *boolean_options[] = {
 265         TRANS_OPT_THIN,
 266         TRANS_OPT_KEEP,
 267         TRANS_OPT_FOLLOWTAGS,
 268         TRANS_OPT_DEEPEN_RELATIVE
 269         };
 270
 271 static int strbuf_set_helper_option(struct helper_data *data,
 272                                     struct strbuf *buf)
 273 {
 274         int ret;
 275
 276         sendline(data, buf);
 277         if (recvline(data, buf))
 278                 exit(128);
 279
 280         if (!strcmp(buf->buf, "ok"))
 281                 ret = 0;
 282         else if (starts_with(buf->buf, "error"))
 283                 ret = -1;
 284         else if (!strcmp(buf->buf, "unsupported"))
 285                 ret = 1;
 286         else {
 287                 warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
 288                 ret = 1;
 289         }
 290         return ret;
 291 }
 292
 293 static int string_list_set_helper_option(struct helper_data *data,
 294                                          const char *name,
 295                                          struct string_list *list)
 296 {
 297         struct strbuf buf = STRBUF_INIT;
 298         int i, ret = 0;
 299
 300         for (i = 0; i < list->nr; i++) {
 301                 strbuf_addf(&buf, "option %s ", name);
 302                 quote_c_style(list->items[i].string, &buf, NULL, 0);
 303                 strbuf_addch(&buf, '\n');
 304
 305                 if ((ret = strbuf_set_helper_option(data, &buf)))
 306                         break;
 307                 strbuf_reset(&buf);
 308         }
 309         strbuf_release(&buf);
 310         return ret;
 311 }
 312
 313 static int set_helper_option(struct transport *transport,
 314                           const char *name, const char *value)
 315 {
 316         struct helper_data *data = transport->data;
 317         struct strbuf buf = STRBUF_INIT;
 318         int i, ret, is_bool = 0;
 319
 320         get_helper(transport);
 321
 322         if (!data->option)
 323                 return 1;
 324
 325         if (!strcmp(name, "deepen-not"))
 326                 return string_list_set_helper_option(data, name,
 327                                                      (struct string_list *)value);
 328
 329         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 330                 if (!strcmp(name, unsupported_options[i]))
 331                         return 1;
 332         }
 333
 334         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 335                 if (!strcmp(name, boolean_options[i])) {
 336                         is_bool = 1;
 337                         break;
 338                 }
 339         }
 340
 341         strbuf_addf(&buf, "option %s ", name);
 342         if (is_bool)
 343                 strbuf_addstr(&buf, value ? "true" : "false");
 344         else
 345                 quote_c_style(value, &buf, NULL, 0);
 346         strbuf_addch(&buf, '\n');
 347
 348         ret = strbuf_set_helper_option(data, &buf);
 349         strbuf_release(&buf);
 350         return ret;
 351 }
 352
 353 static void standard_options(struct transport *t)
 354 {
 355         char buf[16];
 356         int v = t->verbose;
 357
 358         set_helper_option(t, "progress", t->progress ? "true" : "false");
 359
 360         xsnprintf(buf, sizeof(buf), "%d", v + 1);
 361         set_helper_option(t, "verbosity", buf);
 362
 363         switch (t->family) {
 364         case TRANSPORT_FAMILY_ALL:
 365                 /*
 366                  * this is already the default,
 367                  * do not break old remote helpers by setting "all" here
 368                  */
 369                 break;
 370         case TRANSPORT_FAMILY_IPV4:
 371                 set_helper_option(t, "family", "ipv4");
 372                 break;
 373         case TRANSPORT_FAMILY_IPV6:
 374                 set_helper_option(t, "family", "ipv6");
 375                 break;
 376         }
 377 }
 378
 379 static int release_helper(struct transport *transport)
 380 {
 381         int res = 0;
 382         struct helper_data *data = transport->data;
 383         refspec_clear(&data->rs);
 384         res = disconnect_helper(transport);
 385         free(transport->data);
 386         return res;
 387 }
 388
 389 static int fetch_with_fetch(struct transport *transport,
 390                             int nr_heads, struct ref **to_fetch)
 391 {
 392         struct helper_data *data = transport->data;
 393         int i;
 394         struct strbuf buf = STRBUF_INIT;
 395
 396         for (i = 0; i < nr_heads; i++) {
 397                 const struct ref *posn = to_fetch[i];
 398                 if (posn->status & REF_STATUS_UPTODATE)
 399                         continue;
 400
 401                 strbuf_addf(&buf, "fetch %s %s\n",
 402                             oid_to_hex(&posn->old_oid),
 403                             posn->symref ? posn->symref : posn->name);
 404         }
 405
 406         strbuf_addch(&buf, '\n');
 407         sendline(data, &buf);
 408
 409         while (1) {
 410                 const char *name;
 411
 412                 if (recvline(data, &buf))
 413                         exit(128);
 414
 415                 if (skip_prefix(buf.buf, "lock ", &name)) {
 416                         if (transport->pack_lockfiles.nr)
 417                                 warning(_("%s also locked %s"), data->name, name);
 418                         else
 419                                 string_list_append(&transport->pack_lockfiles,
 420                                                    name);
 421                 }
 422                 else if (data->check_connectivity &&
 423                          data->transport_options.check_self_contained_and_connected &&
 424                          !strcmp(buf.buf, "connectivity-ok"))
 425                         data->transport_options.self_contained_and_connected = 1;
 426                 else if (!buf.len)
 427                         break;
 428                 else
 429                         warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
 430         }
 431         strbuf_release(&buf);
 432         return 0;
 433 }
 434
 435 static int get_importer(struct transport *transport, struct child_process *fastimport)
 436 {
 437         struct child_process *helper = get_helper(transport);
 438         struct helper_data *data = transport->data;
 439         int cat_blob_fd, code;
 440         child_process_init(fastimport);
 441         fastimport->in = xdup(helper->out);
 442         strvec_push(&fastimport->args, "fast-import");
 443         strvec_push(&fastimport->args, "--allow-unsafe-features");
 444         strvec_push(&fastimport->args, debug ? "--stats" : "--quiet");
 445
 446         if (data->bidi_import) {
 447                 cat_blob_fd = xdup(helper->in);
 448                 strvec_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 449         }
 450         fastimport->git_cmd = 1;
 451
 452         code = start_command(fastimport);
 453         return code;
 454 }
 455
 456 static int get_exporter(struct transport *transport,
 457                         struct child_process *fastexport,
 458                         struct string_list *revlist_args)
 459 {
 460         struct helper_data *data = transport->data;
 461         struct child_process *helper = get_helper(transport);
 462         int i;
 463
 464         child_process_init(fastexport);
 465
 466         /* we need to duplicate helper->in because we want to use it after
 467          * fastexport is done with it. */
 468         fastexport->out = dup(helper->in);
 469         strvec_push(&fastexport->args, "fast-export");
 470         strvec_push(&fastexport->args, "--use-done-feature");
 471         strvec_push(&fastexport->args, data->signed_tags ?
 472                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 473         if (data->export_marks)
 474                 strvec_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 475         if (data->import_marks)
 476                 strvec_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 477
 478         for (i = 0; i < revlist_args->nr; i++)
 479                 strvec_push(&fastexport->args, revlist_args->items[i].string);
 480
 481         fastexport->git_cmd = 1;
 482         return start_command(fastexport);
 483 }
 484
 485 static int fetch_with_import(struct transport *transport,
 486                              int nr_heads, struct ref **to_fetch)
 487 {
 488         struct child_process fastimport;
 489         struct helper_data *data = transport->data;
 490         int i;
 491         struct ref *posn;
 492         struct strbuf buf = STRBUF_INIT;
 493
 494         get_helper(transport);
 495
 496         if (get_importer(transport, &fastimport))
 497                 die(_("couldn't run fast-import"));
 498
 499         for (i = 0; i < nr_heads; i++) {
 500                 posn = to_fetch[i];
 501                 if (posn->status & REF_STATUS_UPTODATE)
 502                         continue;
 503
 504                 strbuf_addf(&buf, "import %s\n",
 505                             posn->symref ? posn->symref : posn->name);
 506                 sendline(data, &buf);
 507                 strbuf_reset(&buf);
 508         }
 509
 510         write_constant(data->helper->in, "\n");
 511         /*
 512          * remote-helpers that advertise the bidi-import capability are required to
 513          * buffer the complete batch of import commands until this newline before
 514          * sending data to fast-import.
 515          * These helpers read back data from fast-import on their stdin, which could
 516          * be mixed with import commands, otherwise.
 517          */
 518
 519         if (finish_command(&fastimport))
 520                 die(_("error while running fast-import"));
 521
 522         /*
 523          * The fast-import stream of a remote helper that advertises
 524          * the "refspec" capability writes to the refs named after the
 525          * right hand side of the first refspec matching each ref we
 526          * were fetching.
 527          *
 528          * (If no "refspec" capability was specified, for historical
 529          * reasons we default to the equivalent of *:*.)
 530          *
 531          * Store the result in to_fetch[i].old_sha1.  Callers such
 532          * as "git fetch" can use the value to write feedback to the
 533          * terminal, populate FETCH_HEAD, and determine what new value
 534          * should be written to peer_ref if the update is a
 535          * fast-forward or this is a forced update.
 536          */
 537         for (i = 0; i < nr_heads; i++) {
 538                 char *private, *name;
 539                 posn = to_fetch[i];
 540                 if (posn->status & REF_STATUS_UPTODATE)
 541                         continue;
 542                 name = posn->symref ? posn->symref : posn->name;
 543                 if (data->rs.nr)
 544                         private = apply_refspecs(&data->rs, name);
 545                 else
 546                         private = xstrdup(name);
 547                 if (private) {
 548                         if (read_ref(private, &posn->old_oid) < 0)
 549                                 die(_("could not read ref %s"), private);
 550                         free(private);
 551                 }
 552         }
 553         strbuf_release(&buf);
 554         return 0;
 555 }
 556
 557 static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 558 {
 559         struct helper_data *data = transport->data;
 560         int ret = 0;
 561         int duped;
 562         FILE *input;
 563         struct child_process *helper;
 564
 565         helper = get_helper(transport);
 566
 567         /*
 568          * Yes, dup the pipe another time, as we need unbuffered version
 569          * of input pipe as FILE*. fclose() closes the underlying fd and
 570          * stream buffering only can be changed before first I/O operation
 571          * on it.
 572          */
 573         duped = dup(helper->out);
 574         if (duped < 0)
 575                 die_errno(_("can't dup helper output fd"));
 576         input = xfdopen(duped, "r");
 577         setvbuf(input, NULL, _IONBF, 0);
 578
 579         sendline(data, cmdbuf);
 580         if (recvline_fh(input, cmdbuf))
 581                 exit(128);
 582
 583         if (!strcmp(cmdbuf->buf, "")) {
 584                 data->no_disconnect_req = 1;
 585                 if (debug)
 586                         fprintf(stderr, "Debug: Smart transport connection "
 587                                 "ready.\n");
 588                 ret = 1;
 589         } else if (!strcmp(cmdbuf->buf, "fallback")) {
 590                 if (debug)
 591                         fprintf(stderr, "Debug: Falling back to dumb "
 592                                 "transport.\n");
 593         } else {
 594                 die(_("unknown response to connect: %s"),
 595                     cmdbuf->buf);
 596         }
 597
 598         fclose(input);
 599         return ret;
 600 }
 601
 602 static int process_connect_service(struct transport *transport,
 603                                    const char *name, const char *exec)
 604 {
 605         struct helper_data *data = transport->data;
 606         struct strbuf cmdbuf = STRBUF_INIT;
 607         int ret = 0;
 608
 609         /*
 610          * Handle --upload-pack and friends. This is fire and forget...
 611          * just warn if it fails.
 612          */
 613         if (strcmp(name, exec)) {
 614                 int r = set_helper_option(transport, "servpath", exec);
 615                 if (r > 0)
 616                         warning(_("setting remote service path not supported by protocol"));
 617                 else if (r < 0)
 618                         warning(_("invalid remote service path"));
 619         }
 620
 621         if (data->connect) {
 622                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 623                 ret = run_connect(transport, &cmdbuf);
 624         } else if (data->stateless_connect &&
 625                    (get_protocol_version_config() == protocol_v2) &&
 626                    !strcmp("git-upload-pack", name)) {
 627                 strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
 628                 ret = run_connect(transport, &cmdbuf);
 629                 if (ret)
 630                         transport->stateless_rpc = 1;
 631         }
 632
 633         strbuf_release(&cmdbuf);
 634         return ret;
 635 }
 636
 637 static int process_connect(struct transport *transport,
 638                                      int for_push)
 639 {
 640         struct helper_data *data = transport->data;
 641         const char *name;
 642         const char *exec;
 643
 644         name = for_push ? "git-receive-pack" : "git-upload-pack";
 645         if (for_push)
 646                 exec = data->transport_options.receivepack;
 647         else
 648                 exec = data->transport_options.uploadpack;
 649
 650         return process_connect_service(transport, name, exec);
 651 }
 652
 653 static int connect_helper(struct transport *transport, const char *name,
 654                    const char *exec, int fd[2])
 655 {
 656         struct helper_data *data = transport->data;
 657
 658         /* Get_helper so connect is inited. */
 659         get_helper(transport);
 660         if (!data->connect)
 661                 die(_("operation not supported by protocol"));
 662
 663         if (!process_connect_service(transport, name, exec))
 664                 die(_("can't connect to subservice %s"), name);
 665
 666         fd[0] = data->helper->out;
 667         fd[1] = data->helper->in;
 668         return 0;
 669 }
 670
 671 static struct ref *get_refs_list_using_list(struct transport *transport,
 672                                             int for_push);
 673
 674 static int fetch(struct transport *transport,
 675                  int nr_heads, struct ref **to_fetch)
 676 {
 677         struct helper_data *data = transport->data;
 678         int i, count;
 679
 680         get_helper(transport);
 681
 682         if (process_connect(transport, 0)) {
 683                 do_take_over(transport);
 684                 return transport->vtable->fetch(transport, nr_heads, to_fetch);
 685         }
 686
 687         if (!data->get_refs_list_called)
 688                 get_refs_list_using_list(transport, 0);
 689
 690         count = 0;
 691         for (i = 0; i < nr_heads; i++)
 692                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 693                         count++;
 694
 695         if (!count)
 696                 return 0;
 697
 698         if (data->check_connectivity &&
 699             data->transport_options.check_self_contained_and_connected)
 700                 set_helper_option(transport, "check-connectivity", "true");
 701
 702         if (transport->cloning)
 703                 set_helper_option(transport, "cloning", "true");
 704
 705         if (data->transport_options.update_shallow)
 706                 set_helper_option(transport, "update-shallow", "true");
 707
 708         if (data->transport_options.filter_options.choice) {
 709                 const char *spec = expand_list_objects_filter_spec(
 710                         &data->transport_options.filter_options);
 711                 set_helper_option(transport, "filter", spec);
 712         }
 713
 714         if (data->transport_options.negotiation_tips)
 715                 warning("Ignoring --negotiation-tip because the protocol does not support it.");
 716
 717         if (data->fetch)
 718                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 719
 720         if (data->import)
 721                 return fetch_with_import(transport, nr_heads, to_fetch);
 722
 723         return -1;
 724 }
 725
 726 struct push_update_ref_state {
 727         struct ref *hint;
 728         struct ref_push_report *report;
 729         int new_report;
 730 };
 731
 732 static int push_update_ref_status(struct strbuf *buf,
 733                                    struct push_update_ref_state *state,
 734                                    struct ref *remote_refs)
 735 {
 736         char *refname, *msg;
 737         int status, forced = 0;
 738
 739         if (starts_with(buf->buf, "option ")) {
 740                 struct object_id old_oid, new_oid;
 741                 const char *key, *val;
 742                 char *p;
 743
 744                 if (!state->hint || !(state->report || state->new_report))
 745                         die(_("'option' without a matching 'ok/error' directive"));
 746                 if (state->new_report) {
 747                         if (!state->hint->report) {
 748                                 state->hint->report = xcalloc(1, sizeof(struct ref_push_report));
 749                                 state->report = state->hint->report;
 750                         } else {
 751                                 state->report = state->hint->report;
 752                                 while (state->report->next)
 753                                         state->report = state->report->next;
 754                                 state->report->next = xcalloc(1, sizeof(struct ref_push_report));
 755                                 state->report = state->report->next;
 756                         }
 757                         state->new_report = 0;
 758                 }
 759                 key = buf->buf + 7;
 760                 p = strchr(key, ' ');
 761                 if (p)
 762                         *p++ = '\0';
 763                 val = p;
 764                 if (!strcmp(key, "refname"))
 765                         state->report->ref_name = xstrdup_or_null(val);
 766                 else if (!strcmp(key, "old-oid") && val &&
 767                          !parse_oid_hex(val, &old_oid, &val))
 768                         state->report->old_oid = oiddup(&old_oid);
 769                 else if (!strcmp(key, "new-oid") && val &&
 770                          !parse_oid_hex(val, &new_oid, &val))
 771                         state->report->new_oid = oiddup(&new_oid);
 772                 else if (!strcmp(key, "forced-update"))
 773                         state->report->forced_update = 1;
 774                 /* Not update remote namespace again. */
 775                 return 1;
 776         }
 777
 778         state->report = NULL;
 779         state->new_report = 0;
 780
 781         if (starts_with(buf->buf, "ok ")) {
 782                 status = REF_STATUS_OK;
 783                 refname = buf->buf + 3;
 784         } else if (starts_with(buf->buf, "error ")) {
 785                 status = REF_STATUS_REMOTE_REJECT;
 786                 refname = buf->buf + 6;
 787         } else
 788                 die(_("expected ok/error, helper said '%s'"), buf->buf);
 789
 790         msg = strchr(refname, ' ');
 791         if (msg) {
 792                 struct strbuf msg_buf = STRBUF_INIT;
 793                 const char *end;
 794
 795                 *msg++ = '\0';
 796                 if (!unquote_c_style(&msg_buf, msg, &end))
 797                         msg = strbuf_detach(&msg_buf, NULL);
 798                 else
 799                         msg = xstrdup(msg);
 800                 strbuf_release(&msg_buf);
 801
 802                 if (!strcmp(msg, "no match")) {
 803                         status = REF_STATUS_NONE;
 804                         FREE_AND_NULL(msg);
 805                 }
 806                 else if (!strcmp(msg, "up to date")) {
 807                         status = REF_STATUS_UPTODATE;
 808                         FREE_AND_NULL(msg);
 809                 }
 810                 else if (!strcmp(msg, "non-fast forward")) {
 811                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 812                         FREE_AND_NULL(msg);
 813                 }
 814                 else if (!strcmp(msg, "already exists")) {
 815                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 816                         FREE_AND_NULL(msg);
 817                 }
 818                 else if (!strcmp(msg, "fetch first")) {
 819                         status = REF_STATUS_REJECT_FETCH_FIRST;
 820                         FREE_AND_NULL(msg);
 821                 }
 822                 else if (!strcmp(msg, "needs force")) {
 823                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 824                         FREE_AND_NULL(msg);
 825                 }
 826                 else if (!strcmp(msg, "stale info")) {
 827                         status = REF_STATUS_REJECT_STALE;
 828                         FREE_AND_NULL(msg);
 829                 }
 830                 else if (!strcmp(msg, "remote ref updated since checkout")) {
 831                         status = REF_STATUS_REJECT_REMOTE_UPDATED;
 832                         FREE_AND_NULL(msg);
 833                 }
 834                 else if (!strcmp(msg, "forced update")) {
 835                         forced = 1;
 836                         FREE_AND_NULL(msg);
 837                 }
 838         }
 839
 840         if (state->hint)
 841                 state->hint = find_ref_by_name(state->hint, refname);
 842         if (!state->hint)
 843                 state->hint = find_ref_by_name(remote_refs, refname);
 844         if (!state->hint) {
 845                 warning(_("helper reported unexpected status of %s"), refname);
 846                 return 1;
 847         }
 848
 849         if (state->hint->status != REF_STATUS_NONE) {
 850                 /*
 851                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 852                  * status reported by the remote helper if the latter is 'no match'.
 853                  */
 854                 if (status == REF_STATUS_NONE)
 855                         return 1;
 856         }
 857
 858         if (status == REF_STATUS_OK)
 859                 state->new_report = 1;
 860         state->hint->status = status;
 861         state->hint->forced_update |= forced;
 862         state->hint->remote_status = msg;
 863         return !(status == REF_STATUS_OK);
 864 }
 865
 866 static int push_update_refs_status(struct helper_data *data,
 867                                     struct ref *remote_refs,
 868                                     int flags)
 869 {
 870         struct ref *ref;
 871         struct ref_push_report *report;
 872         struct strbuf buf = STRBUF_INIT;
 873         struct push_update_ref_state state = { remote_refs, NULL, 0 };
 874
 875         for (;;) {
 876                 if (recvline(data, &buf)) {
 877                         strbuf_release(&buf);
 878                         return 1;
 879                 }
 880                 if (!buf.len)
 881                         break;
 882                 push_update_ref_status(&buf, &state, remote_refs);
 883         }
 884         strbuf_release(&buf);
 885
 886         if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
 887                 return 0;
 888
 889         /* propagate back the update to the remote namespace */
 890         for (ref = remote_refs; ref; ref = ref->next) {
 891                 char *private;
 892
 893                 if (ref->status != REF_STATUS_OK)
 894                         continue;
 895
 896                 if (!ref->report) {
 897                         private = apply_refspecs(&data->rs, ref->name);
 898                         if (!private)
 899                                 continue;
 900                         update_ref("update by helper", private, &(ref->new_oid),
 901                                    NULL, 0, 0);
 902                         free(private);
 903                 } else {
 904                         for (report = ref->report; report; report = report->next) {
 905                                 private = apply_refspecs(&data->rs,
 906                                                          report->ref_name
 907                                                          ? report->ref_name
 908                                                          : ref->name);
 909                                 if (!private)
 910                                         continue;
 911                                 update_ref("update by helper", private,
 912                                            report->new_oid
 913                                            ? report->new_oid
 914                                            : &(ref->new_oid),
 915                                            NULL, 0, 0);
 916                                 free(private);
 917                         }
 918                 }
 919         }
 920         return 0;
 921 }
 922
 923 static void set_common_push_options(struct transport *transport,
 924                                    const char *name, int flags)
 925 {
 926         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 927                 if (set_helper_option(transport, "dry-run", "true") != 0)
 928                         die(_("helper %s does not support dry-run"), name);
 929         } else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
 930                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 931                         die(_("helper %s does not support --signed"), name);
 932         } else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
 933                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
 934                         die(_("helper %s does not support --signed=if-asked"), name);
 935         }
 936
 937         if (flags & TRANSPORT_PUSH_ATOMIC)
 938                 if (set_helper_option(transport, TRANS_OPT_ATOMIC, "true") != 0)
 939                         die(_("helper %s does not support --atomic"), name);
 940
 941         if (flags & TRANSPORT_PUSH_FORCE_IF_INCLUDES)
 942                 if (set_helper_option(transport, TRANS_OPT_FORCE_IF_INCLUDES, "true") != 0)
 943                         die(_("helper %s does not support --%s"),
 944                             name, TRANS_OPT_FORCE_IF_INCLUDES);
 945
 946         if (flags & TRANSPORT_PUSH_OPTIONS) {
 947                 struct string_list_item *item;
 948                 for_each_string_list_item(item, transport->push_options)
 949                         if (set_helper_option(transport, "push-option", item->string) != 0)
 950                                 die(_("helper %s does not support 'push-option'"), name);
 951         }
 952 }
 953
 954 static int push_refs_with_push(struct transport *transport,
 955                                struct ref *remote_refs, int flags)
 956 {
 957         int force_all = flags & TRANSPORT_PUSH_FORCE;
 958         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 959         int atomic = flags & TRANSPORT_PUSH_ATOMIC;
 960         struct helper_data *data = transport->data;
 961         struct strbuf buf = STRBUF_INIT;
 962         struct ref *ref;
 963         struct string_list cas_options = STRING_LIST_INIT_DUP;
 964         struct string_list_item *cas_option;
 965
 966         get_helper(transport);
 967         if (!data->push)
 968                 return 1;
 969
 970         for (ref = remote_refs; ref; ref = ref->next) {
 971                 if (!ref->peer_ref && !mirror)
 972                         continue;
 973
 974                 /* Check for statuses set by set_ref_status_for_push() */
 975                 switch (ref->status) {
 976                 case REF_STATUS_REJECT_NONFASTFORWARD:
 977                 case REF_STATUS_REJECT_STALE:
 978                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 979                 case REF_STATUS_REJECT_REMOTE_UPDATED:
 980                         if (atomic) {
 981                                 reject_atomic_push(remote_refs, mirror);
 982                                 string_list_clear(&cas_options, 0);
 983                                 return 0;
 984                         } else
 985                                 continue;
 986                 case REF_STATUS_UPTODATE:
 987                         continue;
 988                 default:
 989                         ; /* do nothing */
 990                 }
 991
 992                 if (force_all)
 993                         ref->force = 1;
 994
 995                 strbuf_addstr(&buf, "push ");
 996                 if (!ref->deletion) {
 997                         if (ref->force)
 998                                 strbuf_addch(&buf, '+');
 999                         if (ref->peer_ref)
1000                                 strbuf_addstr(&buf, ref->peer_ref->name);
1001                         else
1002                                 strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
1003                 }
1004                 strbuf_addch(&buf, ':');
1005                 strbuf_addstr(&buf, ref->name);
1006                 strbuf_addch(&buf, '\n');
1007
1008                 /*
1009                  * The "--force-with-lease" options without explicit
1010                  * values to expect have already been expanded into
1011                  * the ref->old_oid_expect[] field; we can ignore
1012                  * transport->smart_options->cas altogether and instead
1013                  * can enumerate them from the refs.
1014                  */
1015                 if (ref->expect_old_sha1) {
1016                         struct strbuf cas = STRBUF_INIT;
1017                         strbuf_addf(&cas, "%s:%s",
1018                                     ref->name, oid_to_hex(&ref->old_oid_expect));
1019                         string_list_append_nodup(&cas_options,
1020                                                  strbuf_detach(&cas, NULL));
1021                 }
1022         }
1023         if (buf.len == 0) {
1024                 string_list_clear(&cas_options, 0);
1025                 return 0;
1026         }
1027
1028         for_each_string_list_item(cas_option, &cas_options)
1029                 set_helper_option(transport, "cas", cas_option->string);
1030         set_common_push_options(transport, data->name, flags);
1031
1032         strbuf_addch(&buf, '\n');
1033         sendline(data, &buf);
1034         strbuf_release(&buf);
1035         string_list_clear(&cas_options, 0);
1036
1037         return push_update_refs_status(data, remote_refs, flags);
1038 }
1039
1040 static int push_refs_with_export(struct transport *transport,
1041                 struct ref *remote_refs, int flags)
1042 {
1043         struct ref *ref;
1044         struct child_process *helper, exporter;
1045         struct helper_data *data = transport->data;
1046         struct string_list revlist_args = STRING_LIST_INIT_DUP;
1047         struct strbuf buf = STRBUF_INIT;
1048
1049         if (!data->rs.nr)
1050                 die(_("remote-helper doesn't support push; refspec needed"));
1051
1052         set_common_push_options(transport, data->name, flags);
1053         if (flags & TRANSPORT_PUSH_FORCE) {
1054                 if (set_helper_option(transport, "force", "true") != 0)
1055                         warning(_("helper %s does not support 'force'"), data->name);
1056         }
1057
1058         helper = get_helper(transport);
1059
1060         write_constant(helper->in, "export\n");
1061
1062         for (ref = remote_refs; ref; ref = ref->next) {
1063                 char *private;
1064                 struct object_id oid;
1065
1066                 private = apply_refspecs(&data->rs, ref->name);
1067                 if (private && !get_oid(private, &oid)) {
1068                         strbuf_addf(&buf, "^%s", private);
1069                         string_list_append_nodup(&revlist_args,
1070                                                  strbuf_detach(&buf, NULL));
1071                         oidcpy(&ref->old_oid, &oid);
1072                 }
1073                 free(private);
1074
1075                 if (ref->peer_ref) {
1076                         if (strcmp(ref->name, ref->peer_ref->name)) {
1077                                 if (!ref->deletion) {
1078                                         const char *name;
1079                                         int flag;
1080
1081                                         /* Follow symbolic refs (mainly for HEAD). */
1082                                         name = resolve_ref_unsafe(ref->peer_ref->name,
1083                                                                   RESOLVE_REF_READING,
1084                                                                   &oid, &flag);
1085                                         if (!name || !(flag & REF_ISSYMREF))
1086                                                 name = ref->peer_ref->name;
1087
1088                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
1089                                 } else
1090                                         strbuf_addf(&buf, ":%s", ref->name);
1091
1092                                 string_list_append(&revlist_args, "--refspec");
1093                                 string_list_append(&revlist_args, buf.buf);
1094                                 strbuf_release(&buf);
1095                         }
1096                         if (!ref->deletion)
1097                                 string_list_append(&revlist_args, ref->peer_ref->name);
1098                 }
1099         }
1100
1101         if (get_exporter(transport, &exporter, &revlist_args))
1102                 die(_("couldn't run fast-export"));
1103
1104         string_list_clear(&revlist_args, 1);
1105
1106         if (finish_command(&exporter))
1107                 die(_("error while running fast-export"));
1108         if (push_update_refs_status(data, remote_refs, flags))
1109                 return 1;
1110
1111         if (data->export_marks) {
1112                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
1113                 rename(buf.buf, data->export_marks);
1114                 strbuf_release(&buf);
1115         }
1116
1117         return 0;
1118 }
1119
1120 static int push_refs(struct transport *transport,
1121                 struct ref *remote_refs, int flags)
1122 {
1123         struct helper_data *data = transport->data;
1124
1125         if (process_connect(transport, 1)) {
1126                 do_take_over(transport);
1127                 return transport->vtable->push_refs(transport, remote_refs, flags);
1128         }
1129
1130         if (!remote_refs) {
1131                 fprintf(stderr,
1132                         _("No refs in common and none specified; doing nothing.\n"
1133                           "Perhaps you should specify a branch.\n"));
1134                 return 0;
1135         }
1136
1137         if (data->push)
1138                 return push_refs_with_push(transport, remote_refs, flags);
1139
1140         if (data->export)
1141                 return push_refs_with_export(transport, remote_refs, flags);
1142
1143         return -1;
1144 }
1145
1146
1147 static int has_attribute(const char *attrs, const char *attr)
1148 {
1149         int len;
1150         if (!attrs)
1151                 return 0;
1152
1153         len = strlen(attr);
1154         for (;;) {
1155                 const char *space = strchrnul(attrs, ' ');
1156                 if (len == space - attrs && !strncmp(attrs, attr, len))
1157                         return 1;
1158                 if (!*space)
1159                         return 0;
1160                 attrs = space + 1;
1161         }
1162 }
1163
1164 static struct ref *get_refs_list(struct transport *transport, int for_push,
1165                                  const struct strvec *ref_prefixes)
1166 {
1167         get_helper(transport);
1168
1169         if (process_connect(transport, for_push)) {
1170                 do_take_over(transport);
1171                 return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
1172         }
1173
1174         return get_refs_list_using_list(transport, for_push);
1175 }
1176
1177 static struct ref *get_refs_list_using_list(struct transport *transport,
1178                                             int for_push)
1179 {
1180         struct helper_data *data = transport->data;
1181         struct child_process *helper;
1182         struct ref *ret = NULL;
1183         struct ref **tail = &ret;
1184         struct ref *posn;
1185         struct strbuf buf = STRBUF_INIT;
1186
1187         data->get_refs_list_called = 1;
1188         helper = get_helper(transport);
1189
1190         if (data->object_format) {
1191                 write_str_in_full(helper->in, "option object-format\n");
1192                 if (recvline(data, &buf) || strcmp(buf.buf, "ok"))
1193                         exit(128);
1194         }
1195
1196         if (data->push && for_push)
1197                 write_str_in_full(helper->in, "list for-push\n");
1198         else
1199                 write_str_in_full(helper->in, "list\n");
1200
1201         while (1) {
1202                 char *eov, *eon;
1203                 if (recvline(data, &buf))
1204                         exit(128);
1205
1206                 if (!*buf.buf)
1207                         break;
1208                 else if (buf.buf[0] == ':') {
1209                         const char *value;
1210                         if (skip_prefix(buf.buf, ":object-format ", &value)) {
1211                                 int algo = hash_algo_by_name(value);
1212                                 if (algo == GIT_HASH_UNKNOWN)
1213                                         die(_("unsupported object format '%s'"),
1214                                             value);
1215                                 transport->hash_algo = &hash_algos[algo];
1216                         }
1217                         continue;
1218                 }
1219
1220                 eov = strchr(buf.buf, ' ');
1221                 if (!eov)
1222                         die(_("malformed response in ref list: %s"), buf.buf);
1223                 eon = strchr(eov + 1, ' ');
1224                 *eov = '\0';
1225                 if (eon)
1226                         *eon = '\0';
1227                 *tail = alloc_ref(eov + 1);
1228                 if (buf.buf[0] == '@')
1229                         (*tail)->symref = xstrdup(buf.buf + 1);
1230                 else if (buf.buf[0] != '?')
1231                         get_oid_hex_algop(buf.buf, &(*tail)->old_oid, transport->hash_algo);
1232                 if (eon) {
1233                         if (has_attribute(eon + 1, "unchanged")) {
1234                                 (*tail)->status |= REF_STATUS_UPTODATE;
1235                                 if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
1236                                         die(_("could not read ref %s"),
1237                                             (*tail)->name);
1238                         }
1239                 }
1240                 tail = &((*tail)->next);
1241         }
1242         if (debug)
1243                 fprintf(stderr, "Debug: Read ref listing.\n");
1244         strbuf_release(&buf);
1245
1246         for (posn = ret; posn; posn = posn->next)
1247                 resolve_remote_symref(posn, ret);
1248
1249         return ret;
1250 }
1251
1252 static struct transport_vtable vtable = {
1253         set_helper_option,
1254         get_refs_list,
1255         fetch,
1256         push_refs,
1257         connect_helper,
1258         release_helper
1259 };
1260
1261 int transport_helper_init(struct transport *transport, const char *name)
1262 {
1263         struct helper_data *data = xcalloc(1, sizeof(*data));
1264         data->name = name;
1265
1266         transport_check_allowed(name);
1267
1268         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1269                 debug = 1;
1270
1271         transport->data = data;
1272         transport->vtable = &vtable;
1273         transport->smart_options = &(data->transport_options);
1274         return 0;
1275 }
1276
1277 /*
1278  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1279  * buffer less), so attempt reads and writes with up to that size.
1280  */
1281 #define BUFFERSIZE 65536
1282 /* This should be enough to hold debugging message. */
1283 #define PBUFFERSIZE 8192
1284
1285 /* Print bidirectional transfer loop debug message. */
1286 __attribute__((format (printf, 1, 2)))
1287 static void transfer_debug(const char *fmt, ...)
1288 {
1289         /*
1290          * NEEDSWORK: This function is sometimes used from multiple threads, and
1291          * we end up using debug_enabled racily. That "should not matter" since
1292          * we always write the same value, but it's still wrong. This function
1293          * is listed in .tsan-suppressions for the time being.
1294          */
1295
1296         va_list args;
1297         char msgbuf[PBUFFERSIZE];
1298         static int debug_enabled = -1;
1299
1300         if (debug_enabled < 0)
1301                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1302         if (!debug_enabled)
1303                 return;
1304
1305         va_start(args, fmt);
1306         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1307         va_end(args);
1308         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1309 }
1310
1311 /* Stream state: More data may be coming in this direction. */
1312 #define SSTATE_TRANSFERRING 0
1313 /*
1314  * Stream state: No more data coming in this direction, flushing rest of
1315  * data.
1316  */
1317 #define SSTATE_FLUSHING 1
1318 /* Stream state: Transfer in this direction finished. */
1319 #define SSTATE_FINISHED 2
1320
1321 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
1322 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1323 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1324
1325 /* Unidirectional transfer. */
1326 struct unidirectional_transfer {
1327         /* Source */
1328         int src;
1329         /* Destination */
1330         int dest;
1331         /* Is source socket? */
1332         int src_is_sock;
1333         /* Is destination socket? */
1334         int dest_is_sock;
1335         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1336         int state;
1337         /* Buffer. */
1338         char buf[BUFFERSIZE];
1339         /* Buffer used. */
1340         size_t bufuse;
1341         /* Name of source. */
1342         const char *src_name;
1343         /* Name of destination. */
1344         const char *dest_name;
1345 };
1346
1347 /* Closes the target (for writing) if transfer has finished. */
1348 static void udt_close_if_finished(struct unidirectional_transfer *t)
1349 {
1350         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1351                 t->state = SSTATE_FINISHED;
1352                 if (t->dest_is_sock)
1353                         shutdown(t->dest, SHUT_WR);
1354                 else
1355                         close(t->dest);
1356                 transfer_debug("Closed %s.", t->dest_name);
1357         }
1358 }
1359
1360 /*
1361  * Tries to read data from source into buffer. If buffer is full,
1362  * no data is read. Returns 0 on success, -1 on error.
1363  */
1364 static int udt_do_read(struct unidirectional_transfer *t)
1365 {
1366         ssize_t bytes;
1367
1368         if (t->bufuse == BUFFERSIZE)
1369                 return 0;       /* No space for more. */
1370
1371         transfer_debug("%s is readable", t->src_name);
1372         bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1373         if (bytes < 0) {
1374                 error_errno(_("read(%s) failed"), t->src_name);
1375                 return -1;
1376         } else if (bytes == 0) {
1377                 transfer_debug("%s EOF (with %i bytes in buffer)",
1378                         t->src_name, (int)t->bufuse);
1379                 t->state = SSTATE_FLUSHING;
1380         } else if (bytes > 0) {
1381                 t->bufuse += bytes;
1382                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1383                         (int)bytes, t->src_name, (int)t->bufuse);
1384         }
1385         return 0;
1386 }
1387
1388 /* Tries to write data from buffer into destination. If buffer is empty,
1389  * no data is written. Returns 0 on success, -1 on error.
1390  */
1391 static int udt_do_write(struct unidirectional_transfer *t)
1392 {
1393         ssize_t bytes;
1394
1395         if (t->bufuse == 0)
1396                 return 0;       /* Nothing to write. */
1397
1398         transfer_debug("%s is writable", t->dest_name);
1399         bytes = xwrite(t->dest, t->buf, t->bufuse);
1400         if (bytes < 0) {
1401                 error_errno(_("write(%s) failed"), t->dest_name);
1402                 return -1;
1403         } else if (bytes > 0) {
1404                 t->bufuse -= bytes;
1405                 if (t->bufuse)
1406                         memmove(t->buf, t->buf + bytes, t->bufuse);
1407                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1408                         (int)bytes, t->dest_name, (int)t->bufuse);
1409         }
1410         return 0;
1411 }
1412
1413
1414 /* State of bidirectional transfer loop. */
1415 struct bidirectional_transfer_state {
1416         /* Direction from program to git. */
1417         struct unidirectional_transfer ptg;
1418         /* Direction from git to program. */
1419         struct unidirectional_transfer gtp;
1420 };
1421
1422 static void *udt_copy_task_routine(void *udt)
1423 {
1424         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1425         while (t->state != SSTATE_FINISHED) {
1426                 if (STATE_NEEDS_READING(t->state))
1427                         if (udt_do_read(t))
1428                                 return NULL;
1429                 if (STATE_NEEDS_WRITING(t->state))
1430                         if (udt_do_write(t))
1431                                 return NULL;
1432                 if (STATE_NEEDS_CLOSING(t->state))
1433                         udt_close_if_finished(t);
1434         }
1435         return udt;     /* Just some non-NULL value. */
1436 }
1437
1438 #ifndef NO_PTHREADS
1439
1440 /*
1441  * Join thread, with appropriate errors on failure. Name is name for the
1442  * thread (for error messages). Returns 0 on success, 1 on failure.
1443  */
1444 static int tloop_join(pthread_t thread, const char *name)
1445 {
1446         int err;
1447         void *tret;
1448         err = pthread_join(thread, &tret);
1449         if (!tret) {
1450                 error(_("%s thread failed"), name);
1451                 return 1;
1452         }
1453         if (err) {
1454                 error(_("%s thread failed to join: %s"), name, strerror(err));
1455                 return 1;
1456         }
1457         return 0;
1458 }
1459
1460 /*
1461  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1462  * -1 on failure.
1463  */
1464 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1465 {
1466         pthread_t gtp_thread;
1467         pthread_t ptg_thread;
1468         int err;
1469         int ret = 0;
1470         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1471                 &s->gtp);
1472         if (err)
1473                 die(_("can't start thread for copying data: %s"), strerror(err));
1474         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1475                 &s->ptg);
1476         if (err)
1477                 die(_("can't start thread for copying data: %s"), strerror(err));
1478
1479         ret |= tloop_join(gtp_thread, "Git to program copy");
1480         ret |= tloop_join(ptg_thread, "Program to git copy");
1481         return ret;
1482 }
1483 #else
1484
1485 /* Close the source and target (for writing) for transfer. */
1486 static void udt_kill_transfer(struct unidirectional_transfer *t)
1487 {
1488         t->state = SSTATE_FINISHED;
1489         /*
1490          * Socket read end left open isn't a disaster if nobody
1491          * attempts to read from it (mingw compat headers do not
1492          * have SHUT_RD)...
1493          *
1494          * We can't fully close the socket since otherwise gtp
1495          * task would first close the socket it sends data to
1496          * while closing the ptg file descriptors.
1497          */
1498         if (!t->src_is_sock)
1499                 close(t->src);
1500         if (t->dest_is_sock)
1501                 shutdown(t->dest, SHUT_WR);
1502         else
1503                 close(t->dest);
1504 }
1505
1506 /*
1507  * Join process, with appropriate errors on failure. Name is name for the
1508  * process (for error messages). Returns 0 on success, 1 on failure.
1509  */
1510 static int tloop_join(pid_t pid, const char *name)
1511 {
1512         int tret;
1513         if (waitpid(pid, &tret, 0) < 0) {
1514                 error_errno(_("%s process failed to wait"), name);
1515                 return 1;
1516         }
1517         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1518                 error(_("%s process failed"), name);
1519                 return 1;
1520         }
1521         return 0;
1522 }
1523
1524 /*
1525  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1526  * -1 on failure.
1527  */
1528 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1529 {
1530         pid_t pid1, pid2;
1531         int ret = 0;
1532
1533         /* Fork thread #1: git to program. */
1534         pid1 = fork();
1535         if (pid1 < 0)
1536                 die_errno(_("can't start thread for copying data"));
1537         else if (pid1 == 0) {
1538                 udt_kill_transfer(&s->ptg);
1539                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1540         }
1541
1542         /* Fork thread #2: program to git. */
1543         pid2 = fork();
1544         if (pid2 < 0)
1545                 die_errno(_("can't start thread for copying data"));
1546         else if (pid2 == 0) {
1547                 udt_kill_transfer(&s->gtp);
1548                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1549         }
1550
1551         /*
1552          * Close both streams in parent as to not interfere with
1553          * end of file detection and wait for both tasks to finish.
1554          */
1555         udt_kill_transfer(&s->gtp);
1556         udt_kill_transfer(&s->ptg);
1557         ret |= tloop_join(pid1, "Git to program copy");
1558         ret |= tloop_join(pid2, "Program to git copy");
1559         return ret;
1560 }
1561 #endif
1562
1563 /*
1564  * Copies data from stdin to output and from input to stdout simultaneously.
1565  * Additionally filtering through given filter. If filter is NULL, uses
1566  * identity filter.
1567  */
1568 int bidirectional_transfer_loop(int input, int output)
1569 {
1570         struct bidirectional_transfer_state state;
1571
1572         /* Fill the state fields. */
1573         state.ptg.src = input;
1574         state.ptg.dest = 1;
1575         state.ptg.src_is_sock = (input == output);
1576         state.ptg.dest_is_sock = 0;
1577         state.ptg.state = SSTATE_TRANSFERRING;
1578         state.ptg.bufuse = 0;
1579         state.ptg.src_name = "remote input";
1580         state.ptg.dest_name = "stdout";
1581
1582         state.gtp.src = 0;
1583         state.gtp.dest = output;
1584         state.gtp.src_is_sock = 0;
1585         state.gtp.dest_is_sock = (input == output);
1586         state.gtp.state = SSTATE_TRANSFERRING;
1587         state.gtp.bufuse = 0;
1588         state.gtp.src_name = "stdin";
1589         state.gtp.dest_name = "remote output";
1590
1591         return tloop_spawnwait_tasks(&state);
1592 }
1593
1594 void reject_atomic_push(struct ref *remote_refs, int mirror_mode)
1595 {
1596         struct ref *ref;
1597
1598         /* Mark other refs as failed */
1599         for (ref = remote_refs; ref; ref = ref->next) {
1600                 if (!ref->peer_ref && !mirror_mode)
1601                         continue;
1602
1603                 switch (ref->status) {
1604                 case REF_STATUS_NONE:
1605                 case REF_STATUS_OK:
1606                 case REF_STATUS_EXPECTING_REPORT:
1607                         ref->status = REF_STATUS_ATOMIC_PUSH_FAILED;
1608                         continue;
1609                 default:
1610                         break; /* do nothing */
1611                 }
1612         }
1613         return;
1614 }