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 "quote.h"
   9 #include "remote.h"
  10 #include "string-list.h"
  11 #include "thread-utils.h"
  12
  13 static int debug;
  14
  15 struct helper_data {
  16         const char *name;
  17         struct child_process *helper;
  18         FILE *out;
  19         unsigned fetch : 1,
  20                 import : 1,
  21                 export : 1,
  22                 option : 1,
  23                 push : 1,
  24                 connect : 1,
  25                 no_disconnect_req : 1;
  26         /* These go from remote name (as in "list") to private name */
  27         struct refspec *refspecs;
  28         int refspec_nr;
  29         /* Transport options for fetch-pack/send-pack (should one of
  30          * those be invoked).
  31          */
  32         struct git_transport_options transport_options;
  33 };
  34
  35 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  36 {
  37         if (debug)
  38                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  39         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  40                 != buffer->len)
  41                 die_errno("Full write to remote helper failed");
  42 }
  43
  44 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  45 {
  46         strbuf_reset(buffer);
  47         if (debug)
  48                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  49         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  50                 if (debug)
  51                         fprintf(stderr, "Debug: Remote helper quit.\n");
  52                 exit(128);
  53         }
  54
  55         if (debug)
  56                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  57         return 0;
  58 }
  59
  60 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  61 {
  62         return recvline_fh(helper->out, buffer);
  63 }
  64
  65 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  66 {
  67         sendline(helper, buffer);
  68         recvline(helper, buffer);
  69 }
  70
  71 static void write_constant(int fd, const char *str)
  72 {
  73         if (debug)
  74                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  75         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  76                 die_errno("Full write to remote helper failed");
  77 }
  78
  79 static const char *remove_ext_force(const char *url)
  80 {
  81         if (url) {
  82                 const char *colon = strchr(url, ':');
  83                 if (colon && colon[1] == ':')
  84                         return colon + 2;
  85         }
  86         return url;
  87 }
  88
  89 static void do_take_over(struct transport *transport)
  90 {
  91         struct helper_data *data;
  92         data = (struct helper_data *)transport->data;
  93         transport_take_over(transport, data->helper);
  94         fclose(data->out);
  95         free(data);
  96 }
  97
  98 static struct child_process *get_helper(struct transport *transport)
  99 {
 100         struct helper_data *data = transport->data;
 101         struct strbuf buf = STRBUF_INIT;
 102         struct child_process *helper;
 103         const char **refspecs = NULL;
 104         int refspec_nr = 0;
 105         int refspec_alloc = 0;
 106         int duped;
 107         int code;
 108
 109         if (data->helper)
 110                 return data->helper;
 111
 112         helper = xcalloc(1, sizeof(*helper));
 113         helper->in = -1;
 114         helper->out = -1;
 115         helper->err = 0;
 116         helper->argv = xcalloc(4, sizeof(*helper->argv));
 117         strbuf_addf(&buf, "git-remote-%s", data->name);
 118         helper->argv[0] = strbuf_detach(&buf, NULL);
 119         helper->argv[1] = transport->remote->name;
 120         helper->argv[2] = remove_ext_force(transport->url);
 121         helper->git_cmd = 0;
 122         helper->silent_exec_failure = 1;
 123         code = start_command(helper);
 124         if (code < 0 && errno == ENOENT)
 125                 die("Unable to find remote helper for '%s'", data->name);
 126         else if (code != 0)
 127                 exit(code);
 128
 129         data->helper = helper;
 130         data->no_disconnect_req = 0;
 131
 132         /*
 133          * Open the output as FILE* so strbuf_getline() can be used.
 134          * Do this with duped fd because fclose() will close the fd,
 135          * and stuff like taking over will require the fd to remain.
 136          */
 137         duped = dup(helper->out);
 138         if (duped < 0)
 139                 die_errno("Can't dup helper output fd");
 140         data->out = xfdopen(duped, "r");
 141
 142         write_constant(helper->in, "capabilities\n");
 143
 144         while (1) {
 145                 const char *capname;
 146                 int mandatory = 0;
 147                 recvline(data, &buf);
 148
 149                 if (!*buf.buf)
 150                         break;
 151
 152                 if (*buf.buf == '*') {
 153                         capname = buf.buf + 1;
 154                         mandatory = 1;
 155                 } else
 156                         capname = buf.buf;
 157
 158                 if (debug)
 159                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 160                 if (!strcmp(capname, "fetch"))
 161                         data->fetch = 1;
 162                 else if (!strcmp(capname, "option"))
 163                         data->option = 1;
 164                 else if (!strcmp(capname, "push"))
 165                         data->push = 1;
 166                 else if (!strcmp(capname, "import"))
 167                         data->import = 1;
 168                 else if (!strcmp(capname, "export"))
 169                         data->export = 1;
 170                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 171                         ALLOC_GROW(refspecs,
 172                                    refspec_nr + 1,
 173                                    refspec_alloc);
 174                         refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
 175                 } else if (!strcmp(capname, "connect")) {
 176                         data->connect = 1;
 177                 } else if (!strcmp(buf.buf, "gitdir")) {
 178                         struct strbuf gitdir = STRBUF_INIT;
 179                         strbuf_addf(&gitdir, "gitdir %s\n", get_git_dir());
 180                         sendline(data, &gitdir);
 181                         strbuf_release(&gitdir);
 182                 } else if (mandatory) {
 183                         die("Unknown mandatory capability %s. This remote "
 184                             "helper probably needs newer version of Git.\n",
 185                             capname);
 186                 }
 187         }
 188         if (refspecs) {
 189                 int i;
 190                 data->refspec_nr = refspec_nr;
 191                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 192                 for (i = 0; i < refspec_nr; i++) {
 193                         free((char *)refspecs[i]);
 194                 }
 195                 free(refspecs);
 196         }
 197         strbuf_release(&buf);
 198         if (debug)
 199                 fprintf(stderr, "Debug: Capabilities complete.\n");
 200         return data->helper;
 201 }
 202
 203 static int disconnect_helper(struct transport *transport)
 204 {
 205         struct helper_data *data = transport->data;
 206         struct strbuf buf = STRBUF_INIT;
 207
 208         if (data->helper) {
 209                 if (debug)
 210                         fprintf(stderr, "Debug: Disconnecting.\n");
 211                 if (!data->no_disconnect_req) {
 212                         strbuf_addf(&buf, "\n");
 213                         sendline(data, &buf);
 214                 }
 215                 close(data->helper->in);
 216                 close(data->helper->out);
 217                 fclose(data->out);
 218                 finish_command(data->helper);
 219                 free((char *)data->helper->argv[0]);
 220                 free(data->helper->argv);
 221                 free(data->helper);
 222                 data->helper = NULL;
 223         }
 224         return 0;
 225 }
 226
 227 static const char *unsupported_options[] = {
 228         TRANS_OPT_UPLOADPACK,
 229         TRANS_OPT_RECEIVEPACK,
 230         TRANS_OPT_THIN,
 231         TRANS_OPT_KEEP
 232         };
 233 static const char *boolean_options[] = {
 234         TRANS_OPT_THIN,
 235         TRANS_OPT_KEEP,
 236         TRANS_OPT_FOLLOWTAGS
 237         };
 238
 239 static int set_helper_option(struct transport *transport,
 240                           const char *name, const char *value)
 241 {
 242         struct helper_data *data = transport->data;
 243         struct strbuf buf = STRBUF_INIT;
 244         int i, ret, is_bool = 0;
 245
 246         get_helper(transport);
 247
 248         if (!data->option)
 249                 return 1;
 250
 251         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 252                 if (!strcmp(name, unsupported_options[i]))
 253                         return 1;
 254         }
 255
 256         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 257                 if (!strcmp(name, boolean_options[i])) {
 258                         is_bool = 1;
 259                         break;
 260                 }
 261         }
 262
 263         strbuf_addf(&buf, "option %s ", name);
 264         if (is_bool)
 265                 strbuf_addstr(&buf, value ? "true" : "false");
 266         else
 267                 quote_c_style(value, &buf, NULL, 0);
 268         strbuf_addch(&buf, '\n');
 269
 270         xchgline(data, &buf);
 271
 272         if (!strcmp(buf.buf, "ok"))
 273                 ret = 0;
 274         else if (!prefixcmp(buf.buf, "error")) {
 275                 ret = -1;
 276         } else if (!strcmp(buf.buf, "unsupported"))
 277                 ret = 1;
 278         else {
 279                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 280                 ret = 1;
 281         }
 282         strbuf_release(&buf);
 283         return ret;
 284 }
 285
 286 static void standard_options(struct transport *t)
 287 {
 288         char buf[16];
 289         int n;
 290         int v = t->verbose;
 291
 292         set_helper_option(t, "progress", t->progress ? "true" : "false");
 293
 294         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 295         if (n >= sizeof(buf))
 296                 die("impossibly large verbosity value");
 297         set_helper_option(t, "verbosity", buf);
 298 }
 299
 300 static int release_helper(struct transport *transport)
 301 {
 302         struct helper_data *data = transport->data;
 303         free_refspec(data->refspec_nr, data->refspecs);
 304         data->refspecs = NULL;
 305         disconnect_helper(transport);
 306         free(transport->data);
 307         return 0;
 308 }
 309
 310 static int fetch_with_fetch(struct transport *transport,
 311                             int nr_heads, struct ref **to_fetch)
 312 {
 313         struct helper_data *data = transport->data;
 314         int i;
 315         struct strbuf buf = STRBUF_INIT;
 316
 317         standard_options(transport);
 318
 319         for (i = 0; i < nr_heads; i++) {
 320                 const struct ref *posn = to_fetch[i];
 321                 if (posn->status & REF_STATUS_UPTODATE)
 322                         continue;
 323
 324                 strbuf_addf(&buf, "fetch %s %s\n",
 325                             sha1_to_hex(posn->old_sha1), posn->name);
 326         }
 327
 328         strbuf_addch(&buf, '\n');
 329         sendline(data, &buf);
 330
 331         while (1) {
 332                 recvline(data, &buf);
 333
 334                 if (!prefixcmp(buf.buf, "lock ")) {
 335                         const char *name = buf.buf + 5;
 336                         if (transport->pack_lockfile)
 337                                 warning("%s also locked %s", data->name, name);
 338                         else
 339                                 transport->pack_lockfile = xstrdup(name);
 340                 }
 341                 else if (!buf.len)
 342                         break;
 343                 else
 344                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 345         }
 346         strbuf_release(&buf);
 347         return 0;
 348 }
 349
 350 static int get_importer(struct transport *transport, struct child_process *fastimport)
 351 {
 352         struct child_process *helper = get_helper(transport);
 353         memset(fastimport, 0, sizeof(*fastimport));
 354         fastimport->in = helper->out;
 355         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 356         fastimport->argv[0] = "fast-import";
 357         fastimport->argv[1] = "--quiet";
 358
 359         fastimport->git_cmd = 1;
 360         return start_command(fastimport);
 361 }
 362
 363 static int get_exporter(struct transport *transport,
 364                         struct child_process *fastexport,
 365                         const char *export_marks,
 366                         const char *import_marks,
 367                         struct string_list *revlist_args)
 368 {
 369         struct child_process *helper = get_helper(transport);
 370         int argc = 0, i;
 371         memset(fastexport, 0, sizeof(*fastexport));
 372
 373         /* we need to duplicate helper->in because we want to use it after
 374          * fastexport is done with it. */
 375         fastexport->out = dup(helper->in);
 376         fastexport->argv = xcalloc(4 + revlist_args->nr, sizeof(*fastexport->argv));
 377         fastexport->argv[argc++] = "fast-export";
 378         if (export_marks)
 379                 fastexport->argv[argc++] = export_marks;
 380         if (import_marks)
 381                 fastexport->argv[argc++] = import_marks;
 382
 383         for (i = 0; i < revlist_args->nr; i++)
 384                 fastexport->argv[argc++] = revlist_args->items[i].string;
 385
 386         fastexport->git_cmd = 1;
 387         return start_command(fastexport);
 388 }
 389
 390 static int fetch_with_import(struct transport *transport,
 391                              int nr_heads, struct ref **to_fetch)
 392 {
 393         struct child_process fastimport;
 394         struct helper_data *data = transport->data;
 395         int i;
 396         struct ref *posn;
 397         struct strbuf buf = STRBUF_INIT;
 398
 399         get_helper(transport);
 400
 401         if (get_importer(transport, &fastimport))
 402                 die("Couldn't run fast-import");
 403
 404         for (i = 0; i < nr_heads; i++) {
 405                 posn = to_fetch[i];
 406                 if (posn->status & REF_STATUS_UPTODATE)
 407                         continue;
 408
 409                 strbuf_addf(&buf, "import %s\n", posn->name);
 410                 sendline(data, &buf);
 411                 strbuf_reset(&buf);
 412         }
 413         disconnect_helper(transport);
 414         finish_command(&fastimport);
 415         free(fastimport.argv);
 416         fastimport.argv = NULL;
 417
 418         for (i = 0; i < nr_heads; i++) {
 419                 char *private;
 420                 posn = to_fetch[i];
 421                 if (posn->status & REF_STATUS_UPTODATE)
 422                         continue;
 423                 if (data->refspecs)
 424                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 425                 else
 426                         private = strdup(posn->name);
 427                 read_ref(private, posn->old_sha1);
 428                 free(private);
 429         }
 430         strbuf_release(&buf);
 431         return 0;
 432 }
 433
 434 static int process_connect_service(struct transport *transport,
 435                                    const char *name, const char *exec)
 436 {
 437         struct helper_data *data = transport->data;
 438         struct strbuf cmdbuf = STRBUF_INIT;
 439         struct child_process *helper;
 440         int r, duped, ret = 0;
 441         FILE *input;
 442
 443         helper = get_helper(transport);
 444
 445         /*
 446          * Yes, dup the pipe another time, as we need unbuffered version
 447          * of input pipe as FILE*. fclose() closes the underlying fd and
 448          * stream buffering only can be changed before first I/O operation
 449          * on it.
 450          */
 451         duped = dup(helper->out);
 452         if (duped < 0)
 453                 die_errno("Can't dup helper output fd");
 454         input = xfdopen(duped, "r");
 455         setvbuf(input, NULL, _IONBF, 0);
 456
 457         /*
 458          * Handle --upload-pack and friends. This is fire and forget...
 459          * just warn if it fails.
 460          */
 461         if (strcmp(name, exec)) {
 462                 r = set_helper_option(transport, "servpath", exec);
 463                 if (r > 0)
 464                         warning("Setting remote service path not supported by protocol.");
 465                 else if (r < 0)
 466                         warning("Invalid remote service path.");
 467         }
 468
 469         if (data->connect)
 470                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 471         else
 472                 goto exit;
 473
 474         sendline(data, &cmdbuf);
 475         recvline_fh(input, &cmdbuf);
 476         if (!strcmp(cmdbuf.buf, "")) {
 477                 data->no_disconnect_req = 1;
 478                 if (debug)
 479                         fprintf(stderr, "Debug: Smart transport connection "
 480                                 "ready.\n");
 481                 ret = 1;
 482         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 483                 if (debug)
 484                         fprintf(stderr, "Debug: Falling back to dumb "
 485                                 "transport.\n");
 486         } else
 487                 die("Unknown response to connect: %s",
 488                         cmdbuf.buf);
 489
 490 exit:
 491         fclose(input);
 492         return ret;
 493 }
 494
 495 static int process_connect(struct transport *transport,
 496                                      int for_push)
 497 {
 498         struct helper_data *data = transport->data;
 499         const char *name;
 500         const char *exec;
 501
 502         name = for_push ? "git-receive-pack" : "git-upload-pack";
 503         if (for_push)
 504                 exec = data->transport_options.receivepack;
 505         else
 506                 exec = data->transport_options.uploadpack;
 507
 508         return process_connect_service(transport, name, exec);
 509 }
 510
 511 static int connect_helper(struct transport *transport, const char *name,
 512                    const char *exec, int fd[2])
 513 {
 514         struct helper_data *data = transport->data;
 515
 516         /* Get_helper so connect is inited. */
 517         get_helper(transport);
 518         if (!data->connect)
 519                 die("Operation not supported by protocol.");
 520
 521         if (!process_connect_service(transport, name, exec))
 522                 die("Can't connect to subservice %s.", name);
 523
 524         fd[0] = data->helper->out;
 525         fd[1] = data->helper->in;
 526         return 0;
 527 }
 528
 529 static int fetch(struct transport *transport,
 530                  int nr_heads, struct ref **to_fetch)
 531 {
 532         struct helper_data *data = transport->data;
 533         int i, count;
 534
 535         if (process_connect(transport, 0)) {
 536                 do_take_over(transport);
 537                 return transport->fetch(transport, nr_heads, to_fetch);
 538         }
 539
 540         count = 0;
 541         for (i = 0; i < nr_heads; i++)
 542                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 543                         count++;
 544
 545         if (!count)
 546                 return 0;
 547
 548         if (data->fetch)
 549                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 550
 551         if (data->import)
 552                 return fetch_with_import(transport, nr_heads, to_fetch);
 553
 554         return -1;
 555 }
 556
 557 static int push_refs_with_push(struct transport *transport,
 558                 struct ref *remote_refs, int flags)
 559 {
 560         int force_all = flags & TRANSPORT_PUSH_FORCE;
 561         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 562         struct helper_data *data = transport->data;
 563         struct strbuf buf = STRBUF_INIT;
 564         struct child_process *helper;
 565         struct ref *ref;
 566
 567         helper = get_helper(transport);
 568         if (!data->push)
 569                 return 1;
 570
 571         for (ref = remote_refs; ref; ref = ref->next) {
 572                 if (!ref->peer_ref && !mirror)
 573                         continue;
 574
 575                 /* Check for statuses set by set_ref_status_for_push() */
 576                 switch (ref->status) {
 577                 case REF_STATUS_REJECT_NONFASTFORWARD:
 578                 case REF_STATUS_UPTODATE:
 579                         continue;
 580                 default:
 581                         ; /* do nothing */
 582                 }
 583
 584                 if (force_all)
 585                         ref->force = 1;
 586
 587                 strbuf_addstr(&buf, "push ");
 588                 if (!ref->deletion) {
 589                         if (ref->force)
 590                                 strbuf_addch(&buf, '+');
 591                         if (ref->peer_ref)
 592                                 strbuf_addstr(&buf, ref->peer_ref->name);
 593                         else
 594                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 595                 }
 596                 strbuf_addch(&buf, ':');
 597                 strbuf_addstr(&buf, ref->name);
 598                 strbuf_addch(&buf, '\n');
 599         }
 600         if (buf.len == 0)
 601                 return 0;
 602
 603         standard_options(transport);
 604
 605         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 606                 if (set_helper_option(transport, "dry-run", "true") != 0)
 607                         die("helper %s does not support dry-run", data->name);
 608         }
 609
 610         strbuf_addch(&buf, '\n');
 611         sendline(data, &buf);
 612
 613         ref = remote_refs;
 614         while (1) {
 615                 char *refname, *msg;
 616                 int status;
 617
 618                 recvline(data, &buf);
 619                 if (!buf.len)
 620                         break;
 621
 622                 if (!prefixcmp(buf.buf, "ok ")) {
 623                         status = REF_STATUS_OK;
 624                         refname = buf.buf + 3;
 625                 } else if (!prefixcmp(buf.buf, "error ")) {
 626                         status = REF_STATUS_REMOTE_REJECT;
 627                         refname = buf.buf + 6;
 628                 } else
 629                         die("expected ok/error, helper said '%s'\n", buf.buf);
 630
 631                 msg = strchr(refname, ' ');
 632                 if (msg) {
 633                         struct strbuf msg_buf = STRBUF_INIT;
 634                         const char *end;
 635
 636                         *msg++ = '\0';
 637                         if (!unquote_c_style(&msg_buf, msg, &end))
 638                                 msg = strbuf_detach(&msg_buf, NULL);
 639                         else
 640                                 msg = xstrdup(msg);
 641                         strbuf_release(&msg_buf);
 642
 643                         if (!strcmp(msg, "no match")) {
 644                                 status = REF_STATUS_NONE;
 645                                 free(msg);
 646                                 msg = NULL;
 647                         }
 648                         else if (!strcmp(msg, "up to date")) {
 649                                 status = REF_STATUS_UPTODATE;
 650                                 free(msg);
 651                                 msg = NULL;
 652                         }
 653                         else if (!strcmp(msg, "non-fast forward")) {
 654                                 status = REF_STATUS_REJECT_NONFASTFORWARD;
 655                                 free(msg);
 656                                 msg = NULL;
 657                         }
 658                 }
 659
 660                 if (ref)
 661                         ref = find_ref_by_name(ref, refname);
 662                 if (!ref)
 663                         ref = find_ref_by_name(remote_refs, refname);
 664                 if (!ref) {
 665                         warning("helper reported unexpected status of %s", refname);
 666                         continue;
 667                 }
 668
 669                 if (ref->status != REF_STATUS_NONE) {
 670                         /*
 671                          * Earlier, the ref was marked not to be pushed, so ignore the ref
 672                          * status reported by the remote helper if the latter is 'no match'.
 673                          */
 674                         if (status == REF_STATUS_NONE)
 675                                 continue;
 676                 }
 677
 678                 ref->status = status;
 679                 ref->remote_status = msg;
 680         }
 681         strbuf_release(&buf);
 682         return 0;
 683 }
 684
 685 static int push_refs_with_export(struct transport *transport,
 686                 struct ref *remote_refs, int flags)
 687 {
 688         struct ref *ref;
 689         struct child_process *helper, exporter;
 690         struct helper_data *data = transport->data;
 691         char *export_marks = NULL, *import_marks = NULL;
 692         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 693         struct strbuf buf = STRBUF_INIT;
 694
 695         helper = get_helper(transport);
 696
 697         write_constant(helper->in, "export\n");
 698
 699         recvline(data, &buf);
 700         if (debug)
 701                 fprintf(stderr, "Debug: Got export_marks '%s'\n", buf.buf);
 702         if (buf.len) {
 703                 struct strbuf arg = STRBUF_INIT;
 704                 strbuf_addstr(&arg, "--export-marks=");
 705                 strbuf_addbuf(&arg, &buf);
 706                 export_marks = strbuf_detach(&arg, NULL);
 707         }
 708
 709         recvline(data, &buf);
 710         if (debug)
 711                 fprintf(stderr, "Debug: Got import_marks '%s'\n", buf.buf);
 712         if (buf.len) {
 713                 struct strbuf arg = STRBUF_INIT;
 714                 strbuf_addstr(&arg, "--import-marks=");
 715                 strbuf_addbuf(&arg, &buf);
 716                 import_marks = strbuf_detach(&arg, NULL);
 717         }
 718
 719         strbuf_reset(&buf);
 720
 721         for (ref = remote_refs; ref; ref = ref->next) {
 722                 char *private;
 723                 unsigned char sha1[20];
 724
 725                 if (!data->refspecs)
 726                         continue;
 727                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 728                 if (private && !get_sha1(private, sha1)) {
 729                         strbuf_addf(&buf, "^%s", private);
 730                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 731                 }
 732
 733                 string_list_append(&revlist_args, ref->name);
 734
 735         }
 736
 737         if (get_exporter(transport, &exporter,
 738                          export_marks, import_marks, &revlist_args))
 739                 die("Couldn't run fast-export");
 740
 741         data->no_disconnect_req = 1;
 742         finish_command(&exporter);
 743         disconnect_helper(transport);
 744         return 0;
 745 }
 746
 747 static int push_refs(struct transport *transport,
 748                 struct ref *remote_refs, int flags)
 749 {
 750         struct helper_data *data = transport->data;
 751
 752         if (process_connect(transport, 1)) {
 753                 do_take_over(transport);
 754                 return transport->push_refs(transport, remote_refs, flags);
 755         }
 756
 757         if (!remote_refs) {
 758                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 759                         "Perhaps you should specify a branch such as 'master'.\n");
 760                 return 0;
 761         }
 762
 763         if (data->push)
 764                 return push_refs_with_push(transport, remote_refs, flags);
 765
 766         if (data->export)
 767                 return push_refs_with_export(transport, remote_refs, flags);
 768
 769         return -1;
 770 }
 771
 772
 773 static int has_attribute(const char *attrs, const char *attr) {
 774         int len;
 775         if (!attrs)
 776                 return 0;
 777
 778         len = strlen(attr);
 779         for (;;) {
 780                 const char *space = strchrnul(attrs, ' ');
 781                 if (len == space - attrs && !strncmp(attrs, attr, len))
 782                         return 1;
 783                 if (!*space)
 784                         return 0;
 785                 attrs = space + 1;
 786         }
 787 }
 788
 789 static struct ref *get_refs_list(struct transport *transport, int for_push)
 790 {
 791         struct helper_data *data = transport->data;
 792         struct child_process *helper;
 793         struct ref *ret = NULL;
 794         struct ref **tail = &ret;
 795         struct ref *posn;
 796         struct strbuf buf = STRBUF_INIT;
 797
 798         helper = get_helper(transport);
 799
 800         if (process_connect(transport, for_push)) {
 801                 do_take_over(transport);
 802                 return transport->get_refs_list(transport, for_push);
 803         }
 804
 805         if (data->push && for_push)
 806                 write_str_in_full(helper->in, "list for-push\n");
 807         else
 808                 write_str_in_full(helper->in, "list\n");
 809
 810         while (1) {
 811                 char *eov, *eon;
 812                 recvline(data, &buf);
 813
 814                 if (!*buf.buf)
 815                         break;
 816
 817                 eov = strchr(buf.buf, ' ');
 818                 if (!eov)
 819                         die("Malformed response in ref list: %s", buf.buf);
 820                 eon = strchr(eov + 1, ' ');
 821                 *eov = '\0';
 822                 if (eon)
 823                         *eon = '\0';
 824                 *tail = alloc_ref(eov + 1);
 825                 if (buf.buf[0] == '@')
 826                         (*tail)->symref = xstrdup(buf.buf + 1);
 827                 else if (buf.buf[0] != '?')
 828                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 829                 if (eon) {
 830                         if (has_attribute(eon + 1, "unchanged")) {
 831                                 (*tail)->status |= REF_STATUS_UPTODATE;
 832                                 read_ref((*tail)->name, (*tail)->old_sha1);
 833                         }
 834                 }
 835                 tail = &((*tail)->next);
 836         }
 837         if (debug)
 838                 fprintf(stderr, "Debug: Read ref listing.\n");
 839         strbuf_release(&buf);
 840
 841         for (posn = ret; posn; posn = posn->next)
 842                 resolve_remote_symref(posn, ret);
 843
 844         return ret;
 845 }
 846
 847 int transport_helper_init(struct transport *transport, const char *name)
 848 {
 849         struct helper_data *data = xcalloc(sizeof(*data), 1);
 850         data->name = name;
 851
 852         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 853                 debug = 1;
 854
 855         transport->data = data;
 856         transport->set_option = set_helper_option;
 857         transport->get_refs_list = get_refs_list;
 858         transport->fetch = fetch;
 859         transport->push_refs = push_refs;
 860         transport->disconnect = release_helper;
 861         transport->connect = connect_helper;
 862         transport->smart_options = &(data->transport_options);
 863         return 0;
 864 }
 865
 866 /*
 867  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 868  * buffer less), so attempt reads and writes with up to that size.
 869  */
 870 #define BUFFERSIZE 65536
 871 /* This should be enough to hold debugging message. */
 872 #define PBUFFERSIZE 8192
 873
 874 /* Print bidirectional transfer loop debug message. */
 875 static void transfer_debug(const char *fmt, ...)
 876 {
 877         va_list args;
 878         char msgbuf[PBUFFERSIZE];
 879         static int debug_enabled = -1;
 880
 881         if (debug_enabled < 0)
 882                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 883         if (!debug_enabled)
 884                 return;
 885
 886         va_start(args, fmt);
 887         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 888         va_end(args);
 889         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 890 }
 891
 892 /* Stream state: More data may be coming in this direction. */
 893 #define SSTATE_TRANSFERING 0
 894 /*
 895  * Stream state: No more data coming in this direction, flushing rest of
 896  * data.
 897  */
 898 #define SSTATE_FLUSHING 1
 899 /* Stream state: Transfer in this direction finished. */
 900 #define SSTATE_FINISHED 2
 901
 902 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 903 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 904 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 905
 906 /* Unidirectional transfer. */
 907 struct unidirectional_transfer {
 908         /* Source */
 909         int src;
 910         /* Destination */
 911         int dest;
 912         /* Is source socket? */
 913         int src_is_sock;
 914         /* Is destination socket? */
 915         int dest_is_sock;
 916         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 917         int state;
 918         /* Buffer. */
 919         char buf[BUFFERSIZE];
 920         /* Buffer used. */
 921         size_t bufuse;
 922         /* Name of source. */
 923         const char *src_name;
 924         /* Name of destination. */
 925         const char *dest_name;
 926 };
 927
 928 /* Closes the target (for writing) if transfer has finished. */
 929 static void udt_close_if_finished(struct unidirectional_transfer *t)
 930 {
 931         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 932                 t->state = SSTATE_FINISHED;
 933                 if (t->dest_is_sock)
 934                         shutdown(t->dest, SHUT_WR);
 935                 else
 936                         close(t->dest);
 937                 transfer_debug("Closed %s.", t->dest_name);
 938         }
 939 }
 940
 941 /*
 942  * Tries to read read data from source into buffer. If buffer is full,
 943  * no data is read. Returns 0 on success, -1 on error.
 944  */
 945 static int udt_do_read(struct unidirectional_transfer *t)
 946 {
 947         ssize_t bytes;
 948
 949         if (t->bufuse == BUFFERSIZE)
 950                 return 0;       /* No space for more. */
 951
 952         transfer_debug("%s is readable", t->src_name);
 953         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 954         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 955                 errno != EINTR) {
 956                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 957                 return -1;
 958         } else if (bytes == 0) {
 959                 transfer_debug("%s EOF (with %i bytes in buffer)",
 960                         t->src_name, t->bufuse);
 961                 t->state = SSTATE_FLUSHING;
 962         } else if (bytes > 0) {
 963                 t->bufuse += bytes;
 964                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 965                         (int)bytes, t->src_name, (int)t->bufuse);
 966         }
 967         return 0;
 968 }
 969
 970 /* Tries to write data from buffer into destination. If buffer is empty,
 971  * no data is written. Returns 0 on success, -1 on error.
 972  */
 973 static int udt_do_write(struct unidirectional_transfer *t)
 974 {
 975         ssize_t bytes;
 976
 977         if (t->bufuse == 0)
 978                 return 0;       /* Nothing to write. */
 979
 980         transfer_debug("%s is writable", t->dest_name);
 981         bytes = write(t->dest, t->buf, t->bufuse);
 982         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 983                 errno != EINTR) {
 984                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
 985                 return -1;
 986         } else if (bytes > 0) {
 987                 t->bufuse -= bytes;
 988                 if (t->bufuse)
 989                         memmove(t->buf, t->buf + bytes, t->bufuse);
 990                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
 991                         (int)bytes, t->dest_name, (int)t->bufuse);
 992         }
 993         return 0;
 994 }
 995
 996
 997 /* State of bidirectional transfer loop. */
 998 struct bidirectional_transfer_state {
 999         /* Direction from program to git. */
1000         struct unidirectional_transfer ptg;
1001         /* Direction from git to program. */
1002         struct unidirectional_transfer gtp;
1003 };
1004
1005 static void *udt_copy_task_routine(void *udt)
1006 {
1007         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1008         while (t->state != SSTATE_FINISHED) {
1009                 if (STATE_NEEDS_READING(t->state))
1010                         if (udt_do_read(t))
1011                                 return NULL;
1012                 if (STATE_NEEDS_WRITING(t->state))
1013                         if (udt_do_write(t))
1014                                 return NULL;
1015                 if (STATE_NEEDS_CLOSING(t->state))
1016                         udt_close_if_finished(t);
1017         }
1018         return udt;     /* Just some non-NULL value. */
1019 }
1020
1021 #ifndef NO_PTHREADS
1022
1023 /*
1024  * Join thread, with apporiate errors on failure. Name is name for the
1025  * thread (for error messages). Returns 0 on success, 1 on failure.
1026  */
1027 static int tloop_join(pthread_t thread, const char *name)
1028 {
1029         int err;
1030         void *tret;
1031         err = pthread_join(thread, &tret);
1032         if (!tret) {
1033                 error("%s thread failed", name);
1034                 return 1;
1035         }
1036         if (err) {
1037                 error("%s thread failed to join: %s", name, strerror(err));
1038                 return 1;
1039         }
1040         return 0;
1041 }
1042
1043 /*
1044  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1045  * -1 on failure.
1046  */
1047 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1048 {
1049         pthread_t gtp_thread;
1050         pthread_t ptg_thread;
1051         int err;
1052         int ret = 0;
1053         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1054                 &s->gtp);
1055         if (err)
1056                 die("Can't start thread for copying data: %s", strerror(err));
1057         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1058                 &s->ptg);
1059         if (err)
1060                 die("Can't start thread for copying data: %s", strerror(err));
1061
1062         ret |= tloop_join(gtp_thread, "Git to program copy");
1063         ret |= tloop_join(ptg_thread, "Program to git copy");
1064         return ret;
1065 }
1066 #else
1067
1068 /* Close the source and target (for writing) for transfer. */
1069 static void udt_kill_transfer(struct unidirectional_transfer *t)
1070 {
1071         t->state = SSTATE_FINISHED;
1072         /*
1073          * Socket read end left open isn't a disaster if nobody
1074          * attempts to read from it (mingw compat headers do not
1075          * have SHUT_RD)...
1076          *
1077          * We can't fully close the socket since otherwise gtp
1078          * task would first close the socket it sends data to
1079          * while closing the ptg file descriptors.
1080          */
1081         if (!t->src_is_sock)
1082                 close(t->src);
1083         if (t->dest_is_sock)
1084                 shutdown(t->dest, SHUT_WR);
1085         else
1086                 close(t->dest);
1087 }
1088
1089 /*
1090  * Join process, with apporiate errors on failure. Name is name for the
1091  * process (for error messages). Returns 0 on success, 1 on failure.
1092  */
1093 static int tloop_join(pid_t pid, const char *name)
1094 {
1095         int tret;
1096         if (waitpid(pid, &tret, 0) < 0) {
1097                 error("%s process failed to wait: %s", name, strerror(errno));
1098                 return 1;
1099         }
1100         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1101                 error("%s process failed", name);
1102                 return 1;
1103         }
1104         return 0;
1105 }
1106
1107 /*
1108  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1109  * -1 on failure.
1110  */
1111 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1112 {
1113         pid_t pid1, pid2;
1114         int ret = 0;
1115
1116         /* Fork thread #1: git to program. */
1117         pid1 = fork();
1118         if (pid1 < 0)
1119                 die_errno("Can't start thread for copying data");
1120         else if (pid1 == 0) {
1121                 udt_kill_transfer(&s->ptg);
1122                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1123         }
1124
1125         /* Fork thread #2: program to git. */
1126         pid2 = fork();
1127         if (pid2 < 0)
1128                 die_errno("Can't start thread for copying data");
1129         else if (pid2 == 0) {
1130                 udt_kill_transfer(&s->gtp);
1131                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1132         }
1133
1134         /*
1135          * Close both streams in parent as to not interfere with
1136          * end of file detection and wait for both tasks to finish.
1137          */
1138         udt_kill_transfer(&s->gtp);
1139         udt_kill_transfer(&s->ptg);
1140         ret |= tloop_join(pid1, "Git to program copy");
1141         ret |= tloop_join(pid2, "Program to git copy");
1142         return ret;
1143 }
1144 #endif
1145
1146 /*
1147  * Copies data from stdin to output and from input to stdout simultaneously.
1148  * Additionally filtering through given filter. If filter is NULL, uses
1149  * identity filter.
1150  */
1151 int bidirectional_transfer_loop(int input, int output)
1152 {
1153         struct bidirectional_transfer_state state;
1154
1155         /* Fill the state fields. */
1156         state.ptg.src = input;
1157         state.ptg.dest = 1;
1158         state.ptg.src_is_sock = (input == output);
1159         state.ptg.dest_is_sock = 0;
1160         state.ptg.state = SSTATE_TRANSFERING;
1161         state.ptg.bufuse = 0;
1162         state.ptg.src_name = "remote input";
1163         state.ptg.dest_name = "stdout";
1164
1165         state.gtp.src = 0;
1166         state.gtp.dest = output;
1167         state.gtp.src_is_sock = 0;
1168         state.gtp.dest_is_sock = (input == output);
1169         state.gtp.state = SSTATE_TRANSFERING;
1170         state.gtp.bufuse = 0;
1171         state.gtp.src_name = "stdin";
1172         state.gtp.dest_name = "remote output";
1173
1174         return tloop_spawnwait_tasks(&state);
1175 }