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
  12 #ifndef NO_PTHREADS
  13 #include <pthread.h>
  14 #include "thread-utils.h"
  15 #endif
  16
  17 static int debug;
  18
  19 struct helper_data
  20 {
  21         const char *name;
  22         struct child_process *helper;
  23         FILE *out;
  24         unsigned fetch : 1,
  25                 import : 1,
  26                 export : 1,
  27                 option : 1,
  28                 push : 1,
  29                 connect : 1,
  30                 no_disconnect_req : 1;
  31         /* These go from remote name (as in "list") to private name */
  32         struct refspec *refspecs;
  33         int refspec_nr;
  34         /* Transport options for fetch-pack/send-pack (should one of
  35          * those be invoked).
  36          */
  37         struct git_transport_options transport_options;
  38 };
  39
  40 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  41 {
  42         if (debug)
  43                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  44         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  45                 != buffer->len)
  46                 die_errno("Full write to remote helper failed");
  47 }
  48
  49 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  50 {
  51         strbuf_reset(buffer);
  52         if (debug)
  53                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  54         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  55                 if (debug)
  56                         fprintf(stderr, "Debug: Remote helper quit.\n");
  57                 exit(128);
  58         }
  59
  60         if (debug)
  61                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  62         return 0;
  63 }
  64
  65 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  66 {
  67         return recvline_fh(helper->out, buffer);
  68 }
  69
  70 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  71 {
  72         sendline(helper, buffer);
  73         recvline(helper, buffer);
  74 }
  75
  76 static void write_constant(int fd, const char *str)
  77 {
  78         if (debug)
  79                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  80         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  81                 die_errno("Full write to remote helper failed");
  82 }
  83
  84 const char *remove_ext_force(const char *url)
  85 {
  86         if (url) {
  87                 const char *colon = strchr(url, ':');
  88                 if (colon && colon[1] == ':')
  89                         return colon + 2;
  90         }
  91         return url;
  92 }
  93
  94 static void do_take_over(struct transport *transport)
  95 {
  96         struct helper_data *data;
  97         data = (struct helper_data *)transport->data;
  98         transport_take_over(transport, data->helper);
  99         fclose(data->out);
 100         free(data);
 101 }
 102
 103 static struct child_process *get_helper(struct transport *transport)
 104 {
 105         struct helper_data *data = transport->data;
 106         struct strbuf buf = STRBUF_INIT;
 107         struct child_process *helper;
 108         const char **refspecs = NULL;
 109         int refspec_nr = 0;
 110         int refspec_alloc = 0;
 111         int duped;
 112         int code;
 113
 114         if (data->helper)
 115                 return data->helper;
 116
 117         helper = xcalloc(1, sizeof(*helper));
 118         helper->in = -1;
 119         helper->out = -1;
 120         helper->err = 0;
 121         helper->argv = xcalloc(4, sizeof(*helper->argv));
 122         strbuf_addf(&buf, "git-remote-%s", data->name);
 123         helper->argv[0] = strbuf_detach(&buf, NULL);
 124         helper->argv[1] = transport->remote->name;
 125         helper->argv[2] = remove_ext_force(transport->url);
 126         helper->git_cmd = 0;
 127         helper->silent_exec_failure = 1;
 128         code = start_command(helper);
 129         if (code < 0 && errno == ENOENT)
 130                 die("Unable to find remote helper for '%s'", data->name);
 131         else if (code != 0)
 132                 exit(code);
 133
 134         data->helper = helper;
 135         data->no_disconnect_req = 0;
 136
 137         /*
 138          * Open the output as FILE* so strbuf_getline() can be used.
 139          * Do this with duped fd because fclose() will close the fd,
 140          * and stuff like taking over will require the fd to remain.
 141          */
 142         duped = dup(helper->out);
 143         if (duped < 0)
 144                 die_errno("Can't dup helper output fd");
 145         data->out = xfdopen(duped, "r");
 146
 147         write_constant(helper->in, "capabilities\n");
 148
 149         while (1) {
 150                 const char *capname;
 151                 int mandatory = 0;
 152                 recvline(data, &buf);
 153
 154                 if (!*buf.buf)
 155                         break;
 156
 157                 if (*buf.buf == '*') {
 158                         capname = buf.buf + 1;
 159                         mandatory = 1;
 160                 } else
 161                         capname = buf.buf;
 162
 163                 if (debug)
 164                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 165                 if (!strcmp(capname, "fetch"))
 166                         data->fetch = 1;
 167                 else if (!strcmp(capname, "option"))
 168                         data->option = 1;
 169                 else if (!strcmp(capname, "push"))
 170                         data->push = 1;
 171                 else if (!strcmp(capname, "import"))
 172                         data->import = 1;
 173                 else if (!strcmp(capname, "export"))
 174                         data->export = 1;
 175                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 176                         ALLOC_GROW(refspecs,
 177                                    refspec_nr + 1,
 178                                    refspec_alloc);
 179                         refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
 180                 } else if (!strcmp(capname, "connect")) {
 181                         data->connect = 1;
 182                 } else if (!strcmp(buf.buf, "gitdir")) {
 183                         struct strbuf gitdir = STRBUF_INIT;
 184                         strbuf_addf(&gitdir, "gitdir %s\n", get_git_dir());
 185                         sendline(data, &gitdir);
 186                         strbuf_release(&gitdir);
 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 child_process *helper;
 570         struct ref *ref;
 571
 572         helper = get_helper(transport);
 573         if (!data->push)
 574                 return 1;
 575
 576         for (ref = remote_refs; ref; ref = ref->next) {
 577                 if (!ref->peer_ref && !mirror)
 578                         continue;
 579
 580                 /* Check for statuses set by set_ref_status_for_push() */
 581                 switch (ref->status) {
 582                 case REF_STATUS_REJECT_NONFASTFORWARD:
 583                 case REF_STATUS_UPTODATE:
 584                         continue;
 585                 default:
 586                         ; /* do nothing */
 587                 }
 588
 589                 if (force_all)
 590                         ref->force = 1;
 591
 592                 strbuf_addstr(&buf, "push ");
 593                 if (!ref->deletion) {
 594                         if (ref->force)
 595                                 strbuf_addch(&buf, '+');
 596                         if (ref->peer_ref)
 597                                 strbuf_addstr(&buf, ref->peer_ref->name);
 598                         else
 599                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 600                 }
 601                 strbuf_addch(&buf, ':');
 602                 strbuf_addstr(&buf, ref->name);
 603                 strbuf_addch(&buf, '\n');
 604         }
 605         if (buf.len == 0)
 606                 return 0;
 607
 608         standard_options(transport);
 609
 610         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 611                 if (set_helper_option(transport, "dry-run", "true") != 0)
 612                         die("helper %s does not support dry-run", data->name);
 613         }
 614
 615         strbuf_addch(&buf, '\n');
 616         sendline(data, &buf);
 617
 618         ref = remote_refs;
 619         while (1) {
 620                 char *refname, *msg;
 621                 int status;
 622
 623                 recvline(data, &buf);
 624                 if (!buf.len)
 625                         break;
 626
 627                 if (!prefixcmp(buf.buf, "ok ")) {
 628                         status = REF_STATUS_OK;
 629                         refname = buf.buf + 3;
 630                 } else if (!prefixcmp(buf.buf, "error ")) {
 631                         status = REF_STATUS_REMOTE_REJECT;
 632                         refname = buf.buf + 6;
 633                 } else
 634                         die("expected ok/error, helper said '%s'\n", buf.buf);
 635
 636                 msg = strchr(refname, ' ');
 637                 if (msg) {
 638                         struct strbuf msg_buf = STRBUF_INIT;
 639                         const char *end;
 640
 641                         *msg++ = '\0';
 642                         if (!unquote_c_style(&msg_buf, msg, &end))
 643                                 msg = strbuf_detach(&msg_buf, NULL);
 644                         else
 645                                 msg = xstrdup(msg);
 646                         strbuf_release(&msg_buf);
 647
 648                         if (!strcmp(msg, "no match")) {
 649                                 status = REF_STATUS_NONE;
 650                                 free(msg);
 651                                 msg = NULL;
 652                         }
 653                         else if (!strcmp(msg, "up to date")) {
 654                                 status = REF_STATUS_UPTODATE;
 655                                 free(msg);
 656                                 msg = NULL;
 657                         }
 658                         else if (!strcmp(msg, "non-fast forward")) {
 659                                 status = REF_STATUS_REJECT_NONFASTFORWARD;
 660                                 free(msg);
 661                                 msg = NULL;
 662                         }
 663                 }
 664
 665                 if (ref)
 666                         ref = find_ref_by_name(ref, refname);
 667                 if (!ref)
 668                         ref = find_ref_by_name(remote_refs, refname);
 669                 if (!ref) {
 670                         warning("helper reported unexpected status of %s", refname);
 671                         continue;
 672                 }
 673
 674                 if (ref->status != REF_STATUS_NONE) {
 675                         /*
 676                          * Earlier, the ref was marked not to be pushed, so ignore the ref
 677                          * status reported by the remote helper if the latter is 'no match'.
 678                          */
 679                         if (status == REF_STATUS_NONE)
 680                                 continue;
 681                 }
 682
 683                 ref->status = status;
 684                 ref->remote_status = msg;
 685         }
 686         strbuf_release(&buf);
 687         return 0;
 688 }
 689
 690 static int push_refs_with_export(struct transport *transport,
 691                 struct ref *remote_refs, int flags)
 692 {
 693         struct ref *ref;
 694         struct child_process *helper, exporter;
 695         struct helper_data *data = transport->data;
 696         char *export_marks = NULL, *import_marks = NULL;
 697         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 698         struct strbuf buf = STRBUF_INIT;
 699
 700         helper = get_helper(transport);
 701
 702         write_constant(helper->in, "export\n");
 703
 704         recvline(data, &buf);
 705         if (debug)
 706                 fprintf(stderr, "Debug: Got export_marks '%s'\n", buf.buf);
 707         if (buf.len) {
 708                 struct strbuf arg = STRBUF_INIT;
 709                 strbuf_addstr(&arg, "--export-marks=");
 710                 strbuf_addbuf(&arg, &buf);
 711                 export_marks = strbuf_detach(&arg, NULL);
 712         }
 713
 714         recvline(data, &buf);
 715         if (debug)
 716                 fprintf(stderr, "Debug: Got import_marks '%s'\n", buf.buf);
 717         if (buf.len) {
 718                 struct strbuf arg = STRBUF_INIT;
 719                 strbuf_addstr(&arg, "--import-marks=");
 720                 strbuf_addbuf(&arg, &buf);
 721                 import_marks = strbuf_detach(&arg, NULL);
 722         }
 723
 724         strbuf_reset(&buf);
 725
 726         for (ref = remote_refs; ref; ref = ref->next) {
 727                 char *private;
 728                 unsigned char sha1[20];
 729
 730                 if (!data->refspecs)
 731                         continue;
 732                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 733                 if (private && !get_sha1(private, sha1)) {
 734                         strbuf_addf(&buf, "^%s", private);
 735                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 736                 }
 737
 738                 string_list_append(&revlist_args, ref->name);
 739
 740         }
 741
 742         if (get_exporter(transport, &exporter,
 743                          export_marks, import_marks, &revlist_args))
 744                 die("Couldn't run fast-export");
 745
 746         data->no_disconnect_req = 1;
 747         finish_command(&exporter);
 748         disconnect_helper(transport);
 749         return 0;
 750 }
 751
 752 static int push_refs(struct transport *transport,
 753                 struct ref *remote_refs, int flags)
 754 {
 755         struct helper_data *data = transport->data;
 756
 757         if (process_connect(transport, 1)) {
 758                 do_take_over(transport);
 759                 return transport->push_refs(transport, remote_refs, flags);
 760         }
 761
 762         if (!remote_refs) {
 763                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 764                         "Perhaps you should specify a branch such as 'master'.\n");
 765                 return 0;
 766         }
 767
 768         if (data->push)
 769                 return push_refs_with_push(transport, remote_refs, flags);
 770
 771         if (data->export)
 772                 return push_refs_with_export(transport, remote_refs, flags);
 773
 774         return -1;
 775 }
 776
 777
 778 static int has_attribute(const char *attrs, const char *attr) {
 779         int len;
 780         if (!attrs)
 781                 return 0;
 782
 783         len = strlen(attr);
 784         for (;;) {
 785                 const char *space = strchrnul(attrs, ' ');
 786                 if (len == space - attrs && !strncmp(attrs, attr, len))
 787                         return 1;
 788                 if (!*space)
 789                         return 0;
 790                 attrs = space + 1;
 791         }
 792 }
 793
 794 static struct ref *get_refs_list(struct transport *transport, int for_push)
 795 {
 796         struct helper_data *data = transport->data;
 797         struct child_process *helper;
 798         struct ref *ret = NULL;
 799         struct ref **tail = &ret;
 800         struct ref *posn;
 801         struct strbuf buf = STRBUF_INIT;
 802
 803         helper = get_helper(transport);
 804
 805         if (process_connect(transport, for_push)) {
 806                 do_take_over(transport);
 807                 return transport->get_refs_list(transport, for_push);
 808         }
 809
 810         if (data->push && for_push)
 811                 write_str_in_full(helper->in, "list for-push\n");
 812         else
 813                 write_str_in_full(helper->in, "list\n");
 814
 815         while (1) {
 816                 char *eov, *eon;
 817                 recvline(data, &buf);
 818
 819                 if (!*buf.buf)
 820                         break;
 821
 822                 eov = strchr(buf.buf, ' ');
 823                 if (!eov)
 824                         die("Malformed response in ref list: %s", buf.buf);
 825                 eon = strchr(eov + 1, ' ');
 826                 *eov = '\0';
 827                 if (eon)
 828                         *eon = '\0';
 829                 *tail = alloc_ref(eov + 1);
 830                 if (buf.buf[0] == '@')
 831                         (*tail)->symref = xstrdup(buf.buf + 1);
 832                 else if (buf.buf[0] != '?')
 833                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 834                 if (eon) {
 835                         if (has_attribute(eon + 1, "unchanged")) {
 836                                 (*tail)->status |= REF_STATUS_UPTODATE;
 837                                 read_ref((*tail)->name, (*tail)->old_sha1);
 838                         }
 839                 }
 840                 tail = &((*tail)->next);
 841         }
 842         if (debug)
 843                 fprintf(stderr, "Debug: Read ref listing.\n");
 844         strbuf_release(&buf);
 845
 846         for (posn = ret; posn; posn = posn->next)
 847                 resolve_remote_symref(posn, ret);
 848
 849         return ret;
 850 }
 851
 852 int transport_helper_init(struct transport *transport, const char *name)
 853 {
 854         struct helper_data *data = xcalloc(sizeof(*data), 1);
 855         data->name = name;
 856
 857         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 858                 debug = 1;
 859
 860         transport->data = data;
 861         transport->set_option = set_helper_option;
 862         transport->get_refs_list = get_refs_list;
 863         transport->fetch = fetch;
 864         transport->push_refs = push_refs;
 865         transport->disconnect = release_helper;
 866         transport->connect = connect_helper;
 867         transport->smart_options = &(data->transport_options);
 868         return 0;
 869 }
 870
 871 /*
 872  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 873  * buffer less), so attempt reads and writes with up to that size.
 874  */
 875 #define BUFFERSIZE 65536
 876 /* This should be enough to hold debugging message. */
 877 #define PBUFFERSIZE 8192
 878
 879 /* Print bidirectional transfer loop debug message. */
 880 static void transfer_debug(const char *fmt, ...)
 881 {
 882         va_list args;
 883         char msgbuf[PBUFFERSIZE];
 884         static int debug_enabled = -1;
 885
 886         if (debug_enabled < 0)
 887                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 888         if (!debug_enabled)
 889                 return;
 890
 891         va_start(args, fmt);
 892         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 893         va_end(args);
 894         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 895 }
 896
 897 /* Stream state: More data may be coming in this direction. */
 898 #define SSTATE_TRANSFERING 0
 899 /*
 900  * Stream state: No more data coming in this direction, flushing rest of
 901  * data.
 902  */
 903 #define SSTATE_FLUSHING 1
 904 /* Stream state: Transfer in this direction finished. */
 905 #define SSTATE_FINISHED 2
 906
 907 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 908 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 909 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 910
 911 /* Unidirectional transfer. */
 912 struct unidirectional_transfer {
 913         /* Source */
 914         int src;
 915         /* Destination */
 916         int dest;
 917         /* Is source socket? */
 918         int src_is_sock;
 919         /* Is destination socket? */
 920         int dest_is_sock;
 921         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 922         int state;
 923         /* Buffer. */
 924         char buf[BUFFERSIZE];
 925         /* Buffer used. */
 926         size_t bufuse;
 927         /* Name of source. */
 928         const char *src_name;
 929         /* Name of destination. */
 930         const char *dest_name;
 931 };
 932
 933 /* Closes the target (for writing) if transfer has finished. */
 934 static void udt_close_if_finished(struct unidirectional_transfer *t)
 935 {
 936         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 937                 t->state = SSTATE_FINISHED;
 938                 if (t->dest_is_sock)
 939                         shutdown(t->dest, SHUT_WR);
 940                 else
 941                         close(t->dest);
 942                 transfer_debug("Closed %s.", t->dest_name);
 943         }
 944 }
 945
 946 /*
 947  * Tries to read read data from source into buffer. If buffer is full,
 948  * no data is read. Returns 0 on success, -1 on error.
 949  */
 950 static int udt_do_read(struct unidirectional_transfer *t)
 951 {
 952         ssize_t bytes;
 953
 954         if (t->bufuse == BUFFERSIZE)
 955                 return 0;       /* No space for more. */
 956
 957         transfer_debug("%s is readable", t->src_name);
 958         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 959         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 960                 errno != EINTR) {
 961                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 962                 return -1;
 963         } else if (bytes == 0) {
 964                 transfer_debug("%s EOF (with %i bytes in buffer)",
 965                         t->src_name, t->bufuse);
 966                 t->state = SSTATE_FLUSHING;
 967         } else if (bytes > 0) {
 968                 t->bufuse += bytes;
 969                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 970                         (int)bytes, t->src_name, (int)t->bufuse);
 971         }
 972         return 0;
 973 }
 974
 975 /* Tries to write data from buffer into destination. If buffer is empty,
 976  * no data is written. Returns 0 on success, -1 on error.
 977  */
 978 static int udt_do_write(struct unidirectional_transfer *t)
 979 {
 980         size_t bytes;
 981
 982         if (t->bufuse == 0)
 983                 return 0;       /* Nothing to write. */
 984
 985         transfer_debug("%s is writable", t->dest_name);
 986         bytes = write(t->dest, t->buf, t->bufuse);
 987         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 988                 errno != EINTR) {
 989                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
 990                 return -1;
 991         } else if (bytes > 0) {
 992                 t->bufuse -= bytes;
 993                 if (t->bufuse)
 994                         memmove(t->buf, t->buf + bytes, t->bufuse);
 995                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
 996                         (int)bytes, t->dest_name, (int)t->bufuse);
 997         }
 998         return 0;
 999 }
1000
1001
1002 /* State of bidirectional transfer loop. */
1003 struct bidirectional_transfer_state {
1004         /* Direction from program to git. */
1005         struct unidirectional_transfer ptg;
1006         /* Direction from git to program. */
1007         struct unidirectional_transfer gtp;
1008 };
1009
1010 static void *udt_copy_task_routine(void *udt)
1011 {
1012         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1013         while (t->state != SSTATE_FINISHED) {
1014                 if (STATE_NEEDS_READING(t->state))
1015                         if (udt_do_read(t))
1016                                 return NULL;
1017                 if (STATE_NEEDS_WRITING(t->state))
1018                         if (udt_do_write(t))
1019                                 return NULL;
1020                 if (STATE_NEEDS_CLOSING(t->state))
1021                         udt_close_if_finished(t);
1022         }
1023         return udt;     /* Just some non-NULL value. */
1024 }
1025
1026 #ifndef NO_PTHREADS
1027
1028 /*
1029  * Join thread, with apporiate errors on failure. Name is name for the
1030  * thread (for error messages). Returns 0 on success, 1 on failure.
1031  */
1032 static int tloop_join(pthread_t thread, const char *name)
1033 {
1034         int err;
1035         void *tret;
1036         err = pthread_join(thread, &tret);
1037         if (!tret) {
1038                 error("%s thread failed", name);
1039                 return 1;
1040         }
1041         if (err) {
1042                 error("%s thread failed to join: %s", name, strerror(err));
1043                 return 1;
1044         }
1045         return 0;
1046 }
1047
1048 /*
1049  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1050  * -1 on failure.
1051  */
1052 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1053 {
1054         pthread_t gtp_thread;
1055         pthread_t ptg_thread;
1056         int err;
1057         int ret = 0;
1058         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1059                 &s->gtp);
1060         if (err)
1061                 die("Can't start thread for copying data: %s", strerror(err));
1062         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1063                 &s->ptg);
1064         if (err)
1065                 die("Can't start thread for copying data: %s", strerror(err));
1066
1067         ret |= tloop_join(gtp_thread, "Git to program copy");
1068         ret |= tloop_join(ptg_thread, "Program to git copy");
1069         return ret;
1070 }
1071 #else
1072
1073 /* Close the source and target (for writing) for transfer. */
1074 static void udt_kill_transfer(struct unidirectional_transfer *t)
1075 {
1076         t->state = SSTATE_FINISHED;
1077         /*
1078          * Socket read end left open isn't a disaster if nobody
1079          * attempts to read from it (mingw compat headers do not
1080          * have SHUT_RD)...
1081          *
1082          * We can't fully close the socket since otherwise gtp
1083          * task would first close the socket it sends data to
1084          * while closing the ptg file descriptors.
1085          */
1086         if (!t->src_is_sock)
1087                 close(t->src);
1088         if (t->dest_is_sock)
1089                 shutdown(t->dest, SHUT_WR);
1090         else
1091                 close(t->dest);
1092 }
1093
1094 /*
1095  * Join process, with apporiate errors on failure. Name is name for the
1096  * process (for error messages). Returns 0 on success, 1 on failure.
1097  */
1098 static int tloop_join(pid_t pid, const char *name)
1099 {
1100         int tret;
1101         if (waitpid(pid, &tret, 0) < 0) {
1102                 error("%s process failed to wait: %s", name, strerror(errno));
1103                 return 1;
1104         }
1105         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1106                 error("%s process failed", name);
1107                 return 1;
1108         }
1109         return 0;
1110 }
1111
1112 /*
1113  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1114  * -1 on failure.
1115  */
1116 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1117 {
1118         pid_t pid1, pid2;
1119         int ret = 0;
1120
1121         /* Fork thread #1: git to program. */
1122         pid1 = fork();
1123         if (pid1 < 0)
1124                 die_errno("Can't start thread for copying data");
1125         else if (pid1 == 0) {
1126                 udt_kill_transfer(&s->ptg);
1127                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1128         }
1129
1130         /* Fork thread #2: program to git. */
1131         pid2 = fork();
1132         if (pid2 < 0)
1133                 die_errno("Can't start thread for copying data");
1134         else if (pid2 == 0) {
1135                 udt_kill_transfer(&s->gtp);
1136                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1137         }
1138
1139         /*
1140          * Close both streams in parent as to not interfere with
1141          * end of file detection and wait for both tasks to finish.
1142          */
1143         udt_kill_transfer(&s->gtp);
1144         udt_kill_transfer(&s->ptg);
1145         ret |= tloop_join(pid1, "Git to program copy");
1146         ret |= tloop_join(pid2, "Program to git copy");
1147         return ret;
1148 }
1149 #endif
1150
1151 /*
1152  * Copies data from stdin to output and from input to stdout simultaneously.
1153  * Additionally filtering through given filter. If filter is NULL, uses
1154  * identity filter.
1155  */
1156 int bidirectional_transfer_loop(int input, int output)
1157 {
1158         struct bidirectional_transfer_state state;
1159
1160         /* Fill the state fields. */
1161         state.ptg.src = input;
1162         state.ptg.dest = 1;
1163         state.ptg.src_is_sock = (input == output);
1164         state.ptg.dest_is_sock = 0;
1165         state.ptg.state = SSTATE_TRANSFERING;
1166         state.ptg.bufuse = 0;
1167         state.ptg.src_name = "remote input";
1168         state.ptg.dest_name = "stdout";
1169
1170         state.gtp.src = 0;
1171         state.gtp.dest = output;
1172         state.gtp.src_is_sock = 0;
1173         state.gtp.dest_is_sock = (input == output);
1174         state.gtp.state = SSTATE_TRANSFERING;
1175         state.gtp.bufuse = 0;
1176         state.gtp.src_name = "stdin";
1177         state.gtp.dest_name = "remote output";
1178
1179         return tloop_spawnwait_tasks(&state);
1180 }