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         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 109         const char *helper_env[] = {
 110                 git_dir_buf,
 111                 NULL
 112         };
 113
 114
 115         if (data->helper)
 116                 return data->helper;
 117
 118         helper = xcalloc(1, sizeof(*helper));
 119         helper->in = -1;
 120         helper->out = -1;
 121         helper->err = 0;
 122         helper->argv = xcalloc(4, sizeof(*helper->argv));
 123         strbuf_addf(&buf, "git-remote-%s", data->name);
 124         helper->argv[0] = strbuf_detach(&buf, NULL);
 125         helper->argv[1] = transport->remote->name;
 126         helper->argv[2] = remove_ext_force(transport->url);
 127         helper->git_cmd = 0;
 128         helper->silent_exec_failure = 1;
 129
 130         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 131         helper->env = helper_env;
 132
 133         code = start_command(helper);
 134         if (code < 0 && errno == ENOENT)
 135                 die("Unable to find remote helper for '%s'", data->name);
 136         else if (code != 0)
 137                 exit(code);
 138
 139         data->helper = helper;
 140         data->no_disconnect_req = 0;
 141
 142         /*
 143          * Open the output as FILE* so strbuf_getline() can be used.
 144          * Do this with duped fd because fclose() will close the fd,
 145          * and stuff like taking over will require the fd to remain.
 146          */
 147         duped = dup(helper->out);
 148         if (duped < 0)
 149                 die_errno("Can't dup helper output fd");
 150         data->out = xfdopen(duped, "r");
 151
 152         write_constant(helper->in, "capabilities\n");
 153
 154         while (1) {
 155                 const char *capname;
 156                 int mandatory = 0;
 157                 recvline(data, &buf);
 158
 159                 if (!*buf.buf)
 160                         break;
 161
 162                 if (*buf.buf == '*') {
 163                         capname = buf.buf + 1;
 164                         mandatory = 1;
 165                 } else
 166                         capname = buf.buf;
 167
 168                 if (debug)
 169                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 170                 if (!strcmp(capname, "fetch"))
 171                         data->fetch = 1;
 172                 else if (!strcmp(capname, "option"))
 173                         data->option = 1;
 174                 else if (!strcmp(capname, "push"))
 175                         data->push = 1;
 176                 else if (!strcmp(capname, "import"))
 177                         data->import = 1;
 178                 else if (!strcmp(capname, "export"))
 179                         data->export = 1;
 180                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 181                         ALLOC_GROW(refspecs,
 182                                    refspec_nr + 1,
 183                                    refspec_alloc);
 184                         refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
 185                 } else if (!strcmp(capname, "connect")) {
 186                         data->connect = 1;
 187                 } else if (mandatory) {
 188                         die("Unknown mandatory capability %s. This remote "
 189                             "helper probably needs newer version of Git.\n",
 190                             capname);
 191                 }
 192         }
 193         if (refspecs) {
 194                 int i;
 195                 data->refspec_nr = refspec_nr;
 196                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 197                 for (i = 0; i < refspec_nr; i++) {
 198                         free((char *)refspecs[i]);
 199                 }
 200                 free(refspecs);
 201         }
 202         strbuf_release(&buf);
 203         if (debug)
 204                 fprintf(stderr, "Debug: Capabilities complete.\n");
 205         return data->helper;
 206 }
 207
 208 static int disconnect_helper(struct transport *transport)
 209 {
 210         struct helper_data *data = transport->data;
 211         struct strbuf buf = STRBUF_INIT;
 212
 213         if (data->helper) {
 214                 if (debug)
 215                         fprintf(stderr, "Debug: Disconnecting.\n");
 216                 if (!data->no_disconnect_req) {
 217                         strbuf_addf(&buf, "\n");
 218                         sendline(data, &buf);
 219                 }
 220                 close(data->helper->in);
 221                 close(data->helper->out);
 222                 fclose(data->out);
 223                 finish_command(data->helper);
 224                 free((char *)data->helper->argv[0]);
 225                 free(data->helper->argv);
 226                 free(data->helper);
 227                 data->helper = NULL;
 228         }
 229         return 0;
 230 }
 231
 232 static const char *unsupported_options[] = {
 233         TRANS_OPT_UPLOADPACK,
 234         TRANS_OPT_RECEIVEPACK,
 235         TRANS_OPT_THIN,
 236         TRANS_OPT_KEEP
 237         };
 238 static const char *boolean_options[] = {
 239         TRANS_OPT_THIN,
 240         TRANS_OPT_KEEP,
 241         TRANS_OPT_FOLLOWTAGS
 242         };
 243
 244 static int set_helper_option(struct transport *transport,
 245                           const char *name, const char *value)
 246 {
 247         struct helper_data *data = transport->data;
 248         struct strbuf buf = STRBUF_INIT;
 249         int i, ret, is_bool = 0;
 250
 251         get_helper(transport);
 252
 253         if (!data->option)
 254                 return 1;
 255
 256         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 257                 if (!strcmp(name, unsupported_options[i]))
 258                         return 1;
 259         }
 260
 261         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 262                 if (!strcmp(name, boolean_options[i])) {
 263                         is_bool = 1;
 264                         break;
 265                 }
 266         }
 267
 268         strbuf_addf(&buf, "option %s ", name);
 269         if (is_bool)
 270                 strbuf_addstr(&buf, value ? "true" : "false");
 271         else
 272                 quote_c_style(value, &buf, NULL, 0);
 273         strbuf_addch(&buf, '\n');
 274
 275         xchgline(data, &buf);
 276
 277         if (!strcmp(buf.buf, "ok"))
 278                 ret = 0;
 279         else if (!prefixcmp(buf.buf, "error")) {
 280                 ret = -1;
 281         } else if (!strcmp(buf.buf, "unsupported"))
 282                 ret = 1;
 283         else {
 284                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 285                 ret = 1;
 286         }
 287         strbuf_release(&buf);
 288         return ret;
 289 }
 290
 291 static void standard_options(struct transport *t)
 292 {
 293         char buf[16];
 294         int n;
 295         int v = t->verbose;
 296
 297         set_helper_option(t, "progress", t->progress ? "true" : "false");
 298
 299         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 300         if (n >= sizeof(buf))
 301                 die("impossibly large verbosity value");
 302         set_helper_option(t, "verbosity", buf);
 303 }
 304
 305 static int release_helper(struct transport *transport)
 306 {
 307         struct helper_data *data = transport->data;
 308         free_refspec(data->refspec_nr, data->refspecs);
 309         data->refspecs = NULL;
 310         disconnect_helper(transport);
 311         free(transport->data);
 312         return 0;
 313 }
 314
 315 static int fetch_with_fetch(struct transport *transport,
 316                             int nr_heads, struct ref **to_fetch)
 317 {
 318         struct helper_data *data = transport->data;
 319         int i;
 320         struct strbuf buf = STRBUF_INIT;
 321
 322         standard_options(transport);
 323
 324         for (i = 0; i < nr_heads; i++) {
 325                 const struct ref *posn = to_fetch[i];
 326                 if (posn->status & REF_STATUS_UPTODATE)
 327                         continue;
 328
 329                 strbuf_addf(&buf, "fetch %s %s\n",
 330                             sha1_to_hex(posn->old_sha1), posn->name);
 331         }
 332
 333         strbuf_addch(&buf, '\n');
 334         sendline(data, &buf);
 335
 336         while (1) {
 337                 recvline(data, &buf);
 338
 339                 if (!prefixcmp(buf.buf, "lock ")) {
 340                         const char *name = buf.buf + 5;
 341                         if (transport->pack_lockfile)
 342                                 warning("%s also locked %s", data->name, name);
 343                         else
 344                                 transport->pack_lockfile = xstrdup(name);
 345                 }
 346                 else if (!buf.len)
 347                         break;
 348                 else
 349                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 350         }
 351         strbuf_release(&buf);
 352         return 0;
 353 }
 354
 355 static int get_importer(struct transport *transport, struct child_process *fastimport)
 356 {
 357         struct child_process *helper = get_helper(transport);
 358         memset(fastimport, 0, sizeof(*fastimport));
 359         fastimport->in = helper->out;
 360         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 361         fastimport->argv[0] = "fast-import";
 362         fastimport->argv[1] = "--quiet";
 363
 364         fastimport->git_cmd = 1;
 365         return start_command(fastimport);
 366 }
 367
 368 static int get_exporter(struct transport *transport,
 369                         struct child_process *fastexport,
 370                         const char *export_marks,
 371                         const char *import_marks,
 372                         struct string_list *revlist_args)
 373 {
 374         struct child_process *helper = get_helper(transport);
 375         int argc = 0, i;
 376         memset(fastexport, 0, sizeof(*fastexport));
 377
 378         /* we need to duplicate helper->in because we want to use it after
 379          * fastexport is done with it. */
 380         fastexport->out = dup(helper->in);
 381         fastexport->argv = xcalloc(4 + revlist_args->nr, sizeof(*fastexport->argv));
 382         fastexport->argv[argc++] = "fast-export";
 383         if (export_marks)
 384                 fastexport->argv[argc++] = export_marks;
 385         if (import_marks)
 386                 fastexport->argv[argc++] = import_marks;
 387
 388         for (i = 0; i < revlist_args->nr; i++)
 389                 fastexport->argv[argc++] = revlist_args->items[i].string;
 390
 391         fastexport->git_cmd = 1;
 392         return start_command(fastexport);
 393 }
 394
 395 static int fetch_with_import(struct transport *transport,
 396                              int nr_heads, struct ref **to_fetch)
 397 {
 398         struct child_process fastimport;
 399         struct helper_data *data = transport->data;
 400         int i;
 401         struct ref *posn;
 402         struct strbuf buf = STRBUF_INIT;
 403
 404         get_helper(transport);
 405
 406         if (get_importer(transport, &fastimport))
 407                 die("Couldn't run fast-import");
 408
 409         for (i = 0; i < nr_heads; i++) {
 410                 posn = to_fetch[i];
 411                 if (posn->status & REF_STATUS_UPTODATE)
 412                         continue;
 413
 414                 strbuf_addf(&buf, "import %s\n", posn->name);
 415                 sendline(data, &buf);
 416                 strbuf_reset(&buf);
 417         }
 418         disconnect_helper(transport);
 419         finish_command(&fastimport);
 420         free(fastimport.argv);
 421         fastimport.argv = NULL;
 422
 423         for (i = 0; i < nr_heads; i++) {
 424                 char *private;
 425                 posn = to_fetch[i];
 426                 if (posn->status & REF_STATUS_UPTODATE)
 427                         continue;
 428                 if (data->refspecs)
 429                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 430                 else
 431                         private = strdup(posn->name);
 432                 read_ref(private, posn->old_sha1);
 433                 free(private);
 434         }
 435         strbuf_release(&buf);
 436         return 0;
 437 }
 438
 439 static int process_connect_service(struct transport *transport,
 440                                    const char *name, const char *exec)
 441 {
 442         struct helper_data *data = transport->data;
 443         struct strbuf cmdbuf = STRBUF_INIT;
 444         struct child_process *helper;
 445         int r, duped, ret = 0;
 446         FILE *input;
 447
 448         helper = get_helper(transport);
 449
 450         /*
 451          * Yes, dup the pipe another time, as we need unbuffered version
 452          * of input pipe as FILE*. fclose() closes the underlying fd and
 453          * stream buffering only can be changed before first I/O operation
 454          * on it.
 455          */
 456         duped = dup(helper->out);
 457         if (duped < 0)
 458                 die_errno("Can't dup helper output fd");
 459         input = xfdopen(duped, "r");
 460         setvbuf(input, NULL, _IONBF, 0);
 461
 462         /*
 463          * Handle --upload-pack and friends. This is fire and forget...
 464          * just warn if it fails.
 465          */
 466         if (strcmp(name, exec)) {
 467                 r = set_helper_option(transport, "servpath", exec);
 468                 if (r > 0)
 469                         warning("Setting remote service path not supported by protocol.");
 470                 else if (r < 0)
 471                         warning("Invalid remote service path.");
 472         }
 473
 474         if (data->connect)
 475                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 476         else
 477                 goto exit;
 478
 479         sendline(data, &cmdbuf);
 480         recvline_fh(input, &cmdbuf);
 481         if (!strcmp(cmdbuf.buf, "")) {
 482                 data->no_disconnect_req = 1;
 483                 if (debug)
 484                         fprintf(stderr, "Debug: Smart transport connection "
 485                                 "ready.\n");
 486                 ret = 1;
 487         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 488                 if (debug)
 489                         fprintf(stderr, "Debug: Falling back to dumb "
 490                                 "transport.\n");
 491         } else
 492                 die("Unknown response to connect: %s",
 493                         cmdbuf.buf);
 494
 495 exit:
 496         fclose(input);
 497         return ret;
 498 }
 499
 500 static int process_connect(struct transport *transport,
 501                                      int for_push)
 502 {
 503         struct helper_data *data = transport->data;
 504         const char *name;
 505         const char *exec;
 506
 507         name = for_push ? "git-receive-pack" : "git-upload-pack";
 508         if (for_push)
 509                 exec = data->transport_options.receivepack;
 510         else
 511                 exec = data->transport_options.uploadpack;
 512
 513         return process_connect_service(transport, name, exec);
 514 }
 515
 516 static int connect_helper(struct transport *transport, const char *name,
 517                    const char *exec, int fd[2])
 518 {
 519         struct helper_data *data = transport->data;
 520
 521         /* Get_helper so connect is inited. */
 522         get_helper(transport);
 523         if (!data->connect)
 524                 die("Operation not supported by protocol.");
 525
 526         if (!process_connect_service(transport, name, exec))
 527                 die("Can't connect to subservice %s.", name);
 528
 529         fd[0] = data->helper->out;
 530         fd[1] = data->helper->in;
 531         return 0;
 532 }
 533
 534 static int fetch(struct transport *transport,
 535                  int nr_heads, struct ref **to_fetch)
 536 {
 537         struct helper_data *data = transport->data;
 538         int i, count;
 539
 540         if (process_connect(transport, 0)) {
 541                 do_take_over(transport);
 542                 return transport->fetch(transport, nr_heads, to_fetch);
 543         }
 544
 545         count = 0;
 546         for (i = 0; i < nr_heads; i++)
 547                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 548                         count++;
 549
 550         if (!count)
 551                 return 0;
 552
 553         if (data->fetch)
 554                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 555
 556         if (data->import)
 557                 return fetch_with_import(transport, nr_heads, to_fetch);
 558
 559         return -1;
 560 }
 561
 562 static int push_refs_with_push(struct transport *transport,
 563                 struct ref *remote_refs, int flags)
 564 {
 565         int force_all = flags & TRANSPORT_PUSH_FORCE;
 566         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 567         struct helper_data *data = transport->data;
 568         struct strbuf buf = STRBUF_INIT;
 569         struct ref *ref;
 570
 571         get_helper(transport);
 572         if (!data->push)
 573                 return 1;
 574
 575         for (ref = remote_refs; ref; ref = ref->next) {
 576                 if (!ref->peer_ref && !mirror)
 577                         continue;
 578
 579                 /* Check for statuses set by set_ref_status_for_push() */
 580                 switch (ref->status) {
 581                 case REF_STATUS_REJECT_NONFASTFORWARD:
 582                 case REF_STATUS_UPTODATE:
 583                         continue;
 584                 default:
 585                         ; /* do nothing */
 586                 }
 587
 588                 if (force_all)
 589                         ref->force = 1;
 590
 591                 strbuf_addstr(&buf, "push ");
 592                 if (!ref->deletion) {
 593                         if (ref->force)
 594                                 strbuf_addch(&buf, '+');
 595                         if (ref->peer_ref)
 596                                 strbuf_addstr(&buf, ref->peer_ref->name);
 597                         else
 598                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 599                 }
 600                 strbuf_addch(&buf, ':');
 601                 strbuf_addstr(&buf, ref->name);
 602                 strbuf_addch(&buf, '\n');
 603         }
 604         if (buf.len == 0)
 605                 return 0;
 606
 607         standard_options(transport);
 608
 609         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 610                 if (set_helper_option(transport, "dry-run", "true") != 0)
 611                         die("helper %s does not support dry-run", data->name);
 612         }
 613
 614         strbuf_addch(&buf, '\n');
 615         sendline(data, &buf);
 616
 617         ref = remote_refs;
 618         while (1) {
 619                 char *refname, *msg;
 620                 int status;
 621
 622                 recvline(data, &buf);
 623                 if (!buf.len)
 624                         break;
 625
 626                 if (!prefixcmp(buf.buf, "ok ")) {
 627                         status = REF_STATUS_OK;
 628                         refname = buf.buf + 3;
 629                 } else if (!prefixcmp(buf.buf, "error ")) {
 630                         status = REF_STATUS_REMOTE_REJECT;
 631                         refname = buf.buf + 6;
 632                 } else
 633                         die("expected ok/error, helper said '%s'\n", buf.buf);
 634
 635                 msg = strchr(refname, ' ');
 636                 if (msg) {
 637                         struct strbuf msg_buf = STRBUF_INIT;
 638                         const char *end;
 639
 640                         *msg++ = '\0';
 641                         if (!unquote_c_style(&msg_buf, msg, &end))
 642                                 msg = strbuf_detach(&msg_buf, NULL);
 643                         else
 644                                 msg = xstrdup(msg);
 645                         strbuf_release(&msg_buf);
 646
 647                         if (!strcmp(msg, "no match")) {
 648                                 status = REF_STATUS_NONE;
 649                                 free(msg);
 650                                 msg = NULL;
 651                         }
 652                         else if (!strcmp(msg, "up to date")) {
 653                                 status = REF_STATUS_UPTODATE;
 654                                 free(msg);
 655                                 msg = NULL;
 656                         }
 657                         else if (!strcmp(msg, "non-fast forward")) {
 658                                 status = REF_STATUS_REJECT_NONFASTFORWARD;
 659                                 free(msg);
 660                                 msg = NULL;
 661                         }
 662                 }
 663
 664                 if (ref)
 665                         ref = find_ref_by_name(ref, refname);
 666                 if (!ref)
 667                         ref = find_ref_by_name(remote_refs, refname);
 668                 if (!ref) {
 669                         warning("helper reported unexpected status of %s", refname);
 670                         continue;
 671                 }
 672
 673                 if (ref->status != REF_STATUS_NONE) {
 674                         /*
 675                          * Earlier, the ref was marked not to be pushed, so ignore the ref
 676                          * status reported by the remote helper if the latter is 'no match'.
 677                          */
 678                         if (status == REF_STATUS_NONE)
 679                                 continue;
 680                 }
 681
 682                 ref->status = status;
 683                 ref->remote_status = msg;
 684         }
 685         strbuf_release(&buf);
 686         return 0;
 687 }
 688
 689 static int push_refs_with_export(struct transport *transport,
 690                 struct ref *remote_refs, int flags)
 691 {
 692         struct ref *ref;
 693         struct child_process *helper, exporter;
 694         struct helper_data *data = transport->data;
 695         char *export_marks = NULL, *import_marks = NULL;
 696         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 697         struct strbuf buf = STRBUF_INIT;
 698
 699         helper = get_helper(transport);
 700
 701         write_constant(helper->in, "export\n");
 702
 703         recvline(data, &buf);
 704         if (debug)
 705                 fprintf(stderr, "Debug: Got export_marks '%s'\n", buf.buf);
 706         if (buf.len) {
 707                 struct strbuf arg = STRBUF_INIT;
 708                 strbuf_addstr(&arg, "--export-marks=");
 709                 strbuf_addbuf(&arg, &buf);
 710                 export_marks = strbuf_detach(&arg, NULL);
 711         }
 712
 713         recvline(data, &buf);
 714         if (debug)
 715                 fprintf(stderr, "Debug: Got import_marks '%s'\n", buf.buf);
 716         if (buf.len) {
 717                 struct strbuf arg = STRBUF_INIT;
 718                 strbuf_addstr(&arg, "--import-marks=");
 719                 strbuf_addbuf(&arg, &buf);
 720                 import_marks = strbuf_detach(&arg, NULL);
 721         }
 722
 723         strbuf_reset(&buf);
 724
 725         for (ref = remote_refs; ref; ref = ref->next) {
 726                 char *private;
 727                 unsigned char sha1[20];
 728
 729                 if (!data->refspecs)
 730                         continue;
 731                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 732                 if (private && !get_sha1(private, sha1)) {
 733                         strbuf_addf(&buf, "^%s", private);
 734                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 735                 }
 736                 free(private);
 737
 738                 if (ref->peer_ref)
 739                         string_list_append(&revlist_args, ref->peer_ref->name);
 740
 741         }
 742
 743         if (get_exporter(transport, &exporter,
 744                          export_marks, import_marks, &revlist_args))
 745                 die("Couldn't run fast-export");
 746
 747         data->no_disconnect_req = 1;
 748         finish_command(&exporter);
 749         disconnect_helper(transport);
 750         return 0;
 751 }
 752
 753 static int push_refs(struct transport *transport,
 754                 struct ref *remote_refs, int flags)
 755 {
 756         struct helper_data *data = transport->data;
 757
 758         if (process_connect(transport, 1)) {
 759                 do_take_over(transport);
 760                 return transport->push_refs(transport, remote_refs, flags);
 761         }
 762
 763         if (!remote_refs) {
 764                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 765                         "Perhaps you should specify a branch such as 'master'.\n");
 766                 return 0;
 767         }
 768
 769         if (data->push)
 770                 return push_refs_with_push(transport, remote_refs, flags);
 771
 772         if (data->export)
 773                 return push_refs_with_export(transport, remote_refs, flags);
 774
 775         return -1;
 776 }
 777
 778
 779 static int has_attribute(const char *attrs, const char *attr) {
 780         int len;
 781         if (!attrs)
 782                 return 0;
 783
 784         len = strlen(attr);
 785         for (;;) {
 786                 const char *space = strchrnul(attrs, ' ');
 787                 if (len == space - attrs && !strncmp(attrs, attr, len))
 788                         return 1;
 789                 if (!*space)
 790                         return 0;
 791                 attrs = space + 1;
 792         }
 793 }
 794
 795 static struct ref *get_refs_list(struct transport *transport, int for_push)
 796 {
 797         struct helper_data *data = transport->data;
 798         struct child_process *helper;
 799         struct ref *ret = NULL;
 800         struct ref **tail = &ret;
 801         struct ref *posn;
 802         struct strbuf buf = STRBUF_INIT;
 803
 804         helper = get_helper(transport);
 805
 806         if (process_connect(transport, for_push)) {
 807                 do_take_over(transport);
 808                 return transport->get_refs_list(transport, for_push);
 809         }
 810
 811         if (data->push && for_push)
 812                 write_str_in_full(helper->in, "list for-push\n");
 813         else
 814                 write_str_in_full(helper->in, "list\n");
 815
 816         while (1) {
 817                 char *eov, *eon;
 818                 recvline(data, &buf);
 819
 820                 if (!*buf.buf)
 821                         break;
 822
 823                 eov = strchr(buf.buf, ' ');
 824                 if (!eov)
 825                         die("Malformed response in ref list: %s", buf.buf);
 826                 eon = strchr(eov + 1, ' ');
 827                 *eov = '\0';
 828                 if (eon)
 829                         *eon = '\0';
 830                 *tail = alloc_ref(eov + 1);
 831                 if (buf.buf[0] == '@')
 832                         (*tail)->symref = xstrdup(buf.buf + 1);
 833                 else if (buf.buf[0] != '?')
 834                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 835                 if (eon) {
 836                         if (has_attribute(eon + 1, "unchanged")) {
 837                                 (*tail)->status |= REF_STATUS_UPTODATE;
 838                                 read_ref((*tail)->name, (*tail)->old_sha1);
 839                         }
 840                 }
 841                 tail = &((*tail)->next);
 842         }
 843         if (debug)
 844                 fprintf(stderr, "Debug: Read ref listing.\n");
 845         strbuf_release(&buf);
 846
 847         for (posn = ret; posn; posn = posn->next)
 848                 resolve_remote_symref(posn, ret);
 849
 850         return ret;
 851 }
 852
 853 int transport_helper_init(struct transport *transport, const char *name)
 854 {
 855         struct helper_data *data = xcalloc(sizeof(*data), 1);
 856         data->name = name;
 857
 858         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 859                 debug = 1;
 860
 861         transport->data = data;
 862         transport->set_option = set_helper_option;
 863         transport->get_refs_list = get_refs_list;
 864         transport->fetch = fetch;
 865         transport->push_refs = push_refs;
 866         transport->disconnect = release_helper;
 867         transport->connect = connect_helper;
 868         transport->smart_options = &(data->transport_options);
 869         return 0;
 870 }
 871
 872 /*
 873  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 874  * buffer less), so attempt reads and writes with up to that size.
 875  */
 876 #define BUFFERSIZE 65536
 877 /* This should be enough to hold debugging message. */
 878 #define PBUFFERSIZE 8192
 879
 880 /* Print bidirectional transfer loop debug message. */
 881 static void transfer_debug(const char *fmt, ...)
 882 {
 883         va_list args;
 884         char msgbuf[PBUFFERSIZE];
 885         static int debug_enabled = -1;
 886
 887         if (debug_enabled < 0)
 888                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 889         if (!debug_enabled)
 890                 return;
 891
 892         va_start(args, fmt);
 893         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 894         va_end(args);
 895         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 896 }
 897
 898 /* Stream state: More data may be coming in this direction. */
 899 #define SSTATE_TRANSFERING 0
 900 /*
 901  * Stream state: No more data coming in this direction, flushing rest of
 902  * data.
 903  */
 904 #define SSTATE_FLUSHING 1
 905 /* Stream state: Transfer in this direction finished. */
 906 #define SSTATE_FINISHED 2
 907
 908 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 909 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 910 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 911
 912 /* Unidirectional transfer. */
 913 struct unidirectional_transfer {
 914         /* Source */
 915         int src;
 916         /* Destination */
 917         int dest;
 918         /* Is source socket? */
 919         int src_is_sock;
 920         /* Is destination socket? */
 921         int dest_is_sock;
 922         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 923         int state;
 924         /* Buffer. */
 925         char buf[BUFFERSIZE];
 926         /* Buffer used. */
 927         size_t bufuse;
 928         /* Name of source. */
 929         const char *src_name;
 930         /* Name of destination. */
 931         const char *dest_name;
 932 };
 933
 934 /* Closes the target (for writing) if transfer has finished. */
 935 static void udt_close_if_finished(struct unidirectional_transfer *t)
 936 {
 937         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 938                 t->state = SSTATE_FINISHED;
 939                 if (t->dest_is_sock)
 940                         shutdown(t->dest, SHUT_WR);
 941                 else
 942                         close(t->dest);
 943                 transfer_debug("Closed %s.", t->dest_name);
 944         }
 945 }
 946
 947 /*
 948  * Tries to read read data from source into buffer. If buffer is full,
 949  * no data is read. Returns 0 on success, -1 on error.
 950  */
 951 static int udt_do_read(struct unidirectional_transfer *t)
 952 {
 953         ssize_t bytes;
 954
 955         if (t->bufuse == BUFFERSIZE)
 956                 return 0;       /* No space for more. */
 957
 958         transfer_debug("%s is readable", t->src_name);
 959         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 960         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 961                 errno != EINTR) {
 962                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 963                 return -1;
 964         } else if (bytes == 0) {
 965                 transfer_debug("%s EOF (with %i bytes in buffer)",
 966                         t->src_name, t->bufuse);
 967                 t->state = SSTATE_FLUSHING;
 968         } else if (bytes > 0) {
 969                 t->bufuse += bytes;
 970                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 971                         (int)bytes, t->src_name, (int)t->bufuse);
 972         }
 973         return 0;
 974 }
 975
 976 /* Tries to write data from buffer into destination. If buffer is empty,
 977  * no data is written. Returns 0 on success, -1 on error.
 978  */
 979 static int udt_do_write(struct unidirectional_transfer *t)
 980 {
 981         ssize_t bytes;
 982
 983         if (t->bufuse == 0)
 984                 return 0;       /* Nothing to write. */
 985
 986         transfer_debug("%s is writable", t->dest_name);
 987         bytes = write(t->dest, t->buf, t->bufuse);
 988         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 989                 errno != EINTR) {
 990                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
 991                 return -1;
 992         } else if (bytes > 0) {
 993                 t->bufuse -= bytes;
 994                 if (t->bufuse)
 995                         memmove(t->buf, t->buf + bytes, t->bufuse);
 996                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
 997                         (int)bytes, t->dest_name, (int)t->bufuse);
 998         }
 999         return 0;
1000 }
1001
1002
1003 /* State of bidirectional transfer loop. */
1004 struct bidirectional_transfer_state {
1005         /* Direction from program to git. */
1006         struct unidirectional_transfer ptg;
1007         /* Direction from git to program. */
1008         struct unidirectional_transfer gtp;
1009 };
1010
1011 static void *udt_copy_task_routine(void *udt)
1012 {
1013         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1014         while (t->state != SSTATE_FINISHED) {
1015                 if (STATE_NEEDS_READING(t->state))
1016                         if (udt_do_read(t))
1017                                 return NULL;
1018                 if (STATE_NEEDS_WRITING(t->state))
1019                         if (udt_do_write(t))
1020                                 return NULL;
1021                 if (STATE_NEEDS_CLOSING(t->state))
1022                         udt_close_if_finished(t);
1023         }
1024         return udt;     /* Just some non-NULL value. */
1025 }
1026
1027 #ifndef NO_PTHREADS
1028
1029 /*
1030  * Join thread, with apporiate errors on failure. Name is name for the
1031  * thread (for error messages). Returns 0 on success, 1 on failure.
1032  */
1033 static int tloop_join(pthread_t thread, const char *name)
1034 {
1035         int err;
1036         void *tret;
1037         err = pthread_join(thread, &tret);
1038         if (!tret) {
1039                 error("%s thread failed", name);
1040                 return 1;
1041         }
1042         if (err) {
1043                 error("%s thread failed to join: %s", name, strerror(err));
1044                 return 1;
1045         }
1046         return 0;
1047 }
1048
1049 /*
1050  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1051  * -1 on failure.
1052  */
1053 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1054 {
1055         pthread_t gtp_thread;
1056         pthread_t ptg_thread;
1057         int err;
1058         int ret = 0;
1059         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1060                 &s->gtp);
1061         if (err)
1062                 die("Can't start thread for copying data: %s", strerror(err));
1063         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1064                 &s->ptg);
1065         if (err)
1066                 die("Can't start thread for copying data: %s", strerror(err));
1067
1068         ret |= tloop_join(gtp_thread, "Git to program copy");
1069         ret |= tloop_join(ptg_thread, "Program to git copy");
1070         return ret;
1071 }
1072 #else
1073
1074 /* Close the source and target (for writing) for transfer. */
1075 static void udt_kill_transfer(struct unidirectional_transfer *t)
1076 {
1077         t->state = SSTATE_FINISHED;
1078         /*
1079          * Socket read end left open isn't a disaster if nobody
1080          * attempts to read from it (mingw compat headers do not
1081          * have SHUT_RD)...
1082          *
1083          * We can't fully close the socket since otherwise gtp
1084          * task would first close the socket it sends data to
1085          * while closing the ptg file descriptors.
1086          */
1087         if (!t->src_is_sock)
1088                 close(t->src);
1089         if (t->dest_is_sock)
1090                 shutdown(t->dest, SHUT_WR);
1091         else
1092                 close(t->dest);
1093 }
1094
1095 /*
1096  * Join process, with apporiate errors on failure. Name is name for the
1097  * process (for error messages). Returns 0 on success, 1 on failure.
1098  */
1099 static int tloop_join(pid_t pid, const char *name)
1100 {
1101         int tret;
1102         if (waitpid(pid, &tret, 0) < 0) {
1103                 error("%s process failed to wait: %s", name, strerror(errno));
1104                 return 1;
1105         }
1106         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1107                 error("%s process failed", name);
1108                 return 1;
1109         }
1110         return 0;
1111 }
1112
1113 /*
1114  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1115  * -1 on failure.
1116  */
1117 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1118 {
1119         pid_t pid1, pid2;
1120         int ret = 0;
1121
1122         /* Fork thread #1: git to program. */
1123         pid1 = fork();
1124         if (pid1 < 0)
1125                 die_errno("Can't start thread for copying data");
1126         else if (pid1 == 0) {
1127                 udt_kill_transfer(&s->ptg);
1128                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1129         }
1130
1131         /* Fork thread #2: program to git. */
1132         pid2 = fork();
1133         if (pid2 < 0)
1134                 die_errno("Can't start thread for copying data");
1135         else if (pid2 == 0) {
1136                 udt_kill_transfer(&s->gtp);
1137                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1138         }
1139
1140         /*
1141          * Close both streams in parent as to not interfere with
1142          * end of file detection and wait for both tasks to finish.
1143          */
1144         udt_kill_transfer(&s->gtp);
1145         udt_kill_transfer(&s->ptg);
1146         ret |= tloop_join(pid1, "Git to program copy");
1147         ret |= tloop_join(pid2, "Program to git copy");
1148         return ret;
1149 }
1150 #endif
1151
1152 /*
1153  * Copies data from stdin to output and from input to stdout simultaneously.
1154  * Additionally filtering through given filter. If filter is NULL, uses
1155  * identity filter.
1156  */
1157 int bidirectional_transfer_loop(int input, int output)
1158 {
1159         struct bidirectional_transfer_state state;
1160
1161         /* Fill the state fields. */
1162         state.ptg.src = input;
1163         state.ptg.dest = 1;
1164         state.ptg.src_is_sock = (input == output);
1165         state.ptg.dest_is_sock = 0;
1166         state.ptg.state = SSTATE_TRANSFERING;
1167         state.ptg.bufuse = 0;
1168         state.ptg.src_name = "remote input";
1169         state.ptg.dest_name = "stdout";
1170
1171         state.gtp.src = 0;
1172         state.gtp.dest = output;
1173         state.gtp.src_is_sock = 0;
1174         state.gtp.dest_is_sock = (input == output);
1175         state.gtp.state = SSTATE_TRANSFERING;
1176         state.gtp.bufuse = 0;
1177         state.gtp.src_name = "stdin";
1178         state.gtp.dest_name = "remote output";
1179
1180         return tloop_spawnwait_tasks(&state);
1181 }