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         int res = 0;
 213
 214         if (data->helper) {
 215                 if (debug)
 216                         fprintf(stderr, "Debug: Disconnecting.\n");
 217                 if (!data->no_disconnect_req) {
 218                         strbuf_addf(&buf, "\n");
 219                         sendline(data, &buf);
 220                 }
 221                 close(data->helper->in);
 222                 close(data->helper->out);
 223                 fclose(data->out);
 224                 res = finish_command(data->helper);
 225                 free((char *)data->helper->argv[0]);
 226                 free(data->helper->argv);
 227                 free(data->helper);
 228                 data->helper = NULL;
 229         }
 230         return res;
 231 }
 232
 233 static const char *unsupported_options[] = {
 234         TRANS_OPT_UPLOADPACK,
 235         TRANS_OPT_RECEIVEPACK,
 236         TRANS_OPT_THIN,
 237         TRANS_OPT_KEEP
 238         };
 239 static const char *boolean_options[] = {
 240         TRANS_OPT_THIN,
 241         TRANS_OPT_KEEP,
 242         TRANS_OPT_FOLLOWTAGS
 243         };
 244
 245 static int set_helper_option(struct transport *transport,
 246                           const char *name, const char *value)
 247 {
 248         struct helper_data *data = transport->data;
 249         struct strbuf buf = STRBUF_INIT;
 250         int i, ret, is_bool = 0;
 251
 252         get_helper(transport);
 253
 254         if (!data->option)
 255                 return 1;
 256
 257         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 258                 if (!strcmp(name, unsupported_options[i]))
 259                         return 1;
 260         }
 261
 262         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 263                 if (!strcmp(name, boolean_options[i])) {
 264                         is_bool = 1;
 265                         break;
 266                 }
 267         }
 268
 269         strbuf_addf(&buf, "option %s ", name);
 270         if (is_bool)
 271                 strbuf_addstr(&buf, value ? "true" : "false");
 272         else
 273                 quote_c_style(value, &buf, NULL, 0);
 274         strbuf_addch(&buf, '\n');
 275
 276         xchgline(data, &buf);
 277
 278         if (!strcmp(buf.buf, "ok"))
 279                 ret = 0;
 280         else if (!prefixcmp(buf.buf, "error")) {
 281                 ret = -1;
 282         } else if (!strcmp(buf.buf, "unsupported"))
 283                 ret = 1;
 284         else {
 285                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 286                 ret = 1;
 287         }
 288         strbuf_release(&buf);
 289         return ret;
 290 }
 291
 292 static void standard_options(struct transport *t)
 293 {
 294         char buf[16];
 295         int n;
 296         int v = t->verbose;
 297
 298         set_helper_option(t, "progress", t->progress ? "true" : "false");
 299
 300         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 301         if (n >= sizeof(buf))
 302                 die("impossibly large verbosity value");
 303         set_helper_option(t, "verbosity", buf);
 304 }
 305
 306 static int release_helper(struct transport *transport)
 307 {
 308         int res = 0;
 309         struct helper_data *data = transport->data;
 310         free_refspec(data->refspec_nr, data->refspecs);
 311         data->refspecs = NULL;
 312         res = disconnect_helper(transport);
 313         free(transport->data);
 314         return res;
 315 }
 316
 317 static int fetch_with_fetch(struct transport *transport,
 318                             int nr_heads, struct ref **to_fetch)
 319 {
 320         struct helper_data *data = transport->data;
 321         int i;
 322         struct strbuf buf = STRBUF_INIT;
 323
 324         standard_options(transport);
 325
 326         for (i = 0; i < nr_heads; i++) {
 327                 const struct ref *posn = to_fetch[i];
 328                 if (posn->status & REF_STATUS_UPTODATE)
 329                         continue;
 330
 331                 strbuf_addf(&buf, "fetch %s %s\n",
 332                             sha1_to_hex(posn->old_sha1), posn->name);
 333         }
 334
 335         strbuf_addch(&buf, '\n');
 336         sendline(data, &buf);
 337
 338         while (1) {
 339                 recvline(data, &buf);
 340
 341                 if (!prefixcmp(buf.buf, "lock ")) {
 342                         const char *name = buf.buf + 5;
 343                         if (transport->pack_lockfile)
 344                                 warning("%s also locked %s", data->name, name);
 345                         else
 346                                 transport->pack_lockfile = xstrdup(name);
 347                 }
 348                 else if (!buf.len)
 349                         break;
 350                 else
 351                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 352         }
 353         strbuf_release(&buf);
 354         return 0;
 355 }
 356
 357 static int get_importer(struct transport *transport, struct child_process *fastimport)
 358 {
 359         struct child_process *helper = get_helper(transport);
 360         memset(fastimport, 0, sizeof(*fastimport));
 361         fastimport->in = helper->out;
 362         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 363         fastimport->argv[0] = "fast-import";
 364         fastimport->argv[1] = "--quiet";
 365
 366         fastimport->git_cmd = 1;
 367         return start_command(fastimport);
 368 }
 369
 370 static int get_exporter(struct transport *transport,
 371                         struct child_process *fastexport,
 372                         const char *export_marks,
 373                         const char *import_marks,
 374                         struct string_list *revlist_args)
 375 {
 376         struct child_process *helper = get_helper(transport);
 377         int argc = 0, i;
 378         memset(fastexport, 0, sizeof(*fastexport));
 379
 380         /* we need to duplicate helper->in because we want to use it after
 381          * fastexport is done with it. */
 382         fastexport->out = dup(helper->in);
 383         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
 384         fastexport->argv[argc++] = "fast-export";
 385         fastexport->argv[argc++] = "--use-done-feature";
 386         if (export_marks)
 387                 fastexport->argv[argc++] = export_marks;
 388         if (import_marks)
 389                 fastexport->argv[argc++] = import_marks;
 390
 391         for (i = 0; i < revlist_args->nr; i++)
 392                 fastexport->argv[argc++] = revlist_args->items[i].string;
 393
 394         fastexport->git_cmd = 1;
 395         return start_command(fastexport);
 396 }
 397
 398 static int fetch_with_import(struct transport *transport,
 399                              int nr_heads, struct ref **to_fetch)
 400 {
 401         struct child_process fastimport;
 402         struct helper_data *data = transport->data;
 403         int i;
 404         struct ref *posn;
 405         struct strbuf buf = STRBUF_INIT;
 406
 407         get_helper(transport);
 408
 409         if (get_importer(transport, &fastimport))
 410                 die("Couldn't run fast-import");
 411
 412         for (i = 0; i < nr_heads; i++) {
 413                 posn = to_fetch[i];
 414                 if (posn->status & REF_STATUS_UPTODATE)
 415                         continue;
 416
 417                 strbuf_addf(&buf, "import %s\n", posn->name);
 418                 sendline(data, &buf);
 419                 strbuf_reset(&buf);
 420         }
 421         if (finish_command(&fastimport))
 422                 die("Error while running fast-import");
 423         free(fastimport.argv);
 424         fastimport.argv = NULL;
 425
 426         for (i = 0; i < nr_heads; i++) {
 427                 char *private;
 428                 posn = to_fetch[i];
 429                 if (posn->status & REF_STATUS_UPTODATE)
 430                         continue;
 431                 if (data->refspecs)
 432                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 433                 else
 434                         private = strdup(posn->name);
 435                 read_ref(private, posn->old_sha1);
 436                 free(private);
 437         }
 438         strbuf_release(&buf);
 439         return 0;
 440 }
 441
 442 static int process_connect_service(struct transport *transport,
 443                                    const char *name, const char *exec)
 444 {
 445         struct helper_data *data = transport->data;
 446         struct strbuf cmdbuf = STRBUF_INIT;
 447         struct child_process *helper;
 448         int r, duped, ret = 0;
 449         FILE *input;
 450
 451         helper = get_helper(transport);
 452
 453         /*
 454          * Yes, dup the pipe another time, as we need unbuffered version
 455          * of input pipe as FILE*. fclose() closes the underlying fd and
 456          * stream buffering only can be changed before first I/O operation
 457          * on it.
 458          */
 459         duped = dup(helper->out);
 460         if (duped < 0)
 461                 die_errno("Can't dup helper output fd");
 462         input = xfdopen(duped, "r");
 463         setvbuf(input, NULL, _IONBF, 0);
 464
 465         /*
 466          * Handle --upload-pack and friends. This is fire and forget...
 467          * just warn if it fails.
 468          */
 469         if (strcmp(name, exec)) {
 470                 r = set_helper_option(transport, "servpath", exec);
 471                 if (r > 0)
 472                         warning("Setting remote service path not supported by protocol.");
 473                 else if (r < 0)
 474                         warning("Invalid remote service path.");
 475         }
 476
 477         if (data->connect)
 478                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 479         else
 480                 goto exit;
 481
 482         sendline(data, &cmdbuf);
 483         recvline_fh(input, &cmdbuf);
 484         if (!strcmp(cmdbuf.buf, "")) {
 485                 data->no_disconnect_req = 1;
 486                 if (debug)
 487                         fprintf(stderr, "Debug: Smart transport connection "
 488                                 "ready.\n");
 489                 ret = 1;
 490         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 491                 if (debug)
 492                         fprintf(stderr, "Debug: Falling back to dumb "
 493                                 "transport.\n");
 494         } else
 495                 die("Unknown response to connect: %s",
 496                         cmdbuf.buf);
 497
 498 exit:
 499         fclose(input);
 500         return ret;
 501 }
 502
 503 static int process_connect(struct transport *transport,
 504                                      int for_push)
 505 {
 506         struct helper_data *data = transport->data;
 507         const char *name;
 508         const char *exec;
 509
 510         name = for_push ? "git-receive-pack" : "git-upload-pack";
 511         if (for_push)
 512                 exec = data->transport_options.receivepack;
 513         else
 514                 exec = data->transport_options.uploadpack;
 515
 516         return process_connect_service(transport, name, exec);
 517 }
 518
 519 static int connect_helper(struct transport *transport, const char *name,
 520                    const char *exec, int fd[2])
 521 {
 522         struct helper_data *data = transport->data;
 523
 524         /* Get_helper so connect is inited. */
 525         get_helper(transport);
 526         if (!data->connect)
 527                 die("Operation not supported by protocol.");
 528
 529         if (!process_connect_service(transport, name, exec))
 530                 die("Can't connect to subservice %s.", name);
 531
 532         fd[0] = data->helper->out;
 533         fd[1] = data->helper->in;
 534         return 0;
 535 }
 536
 537 static int fetch(struct transport *transport,
 538                  int nr_heads, struct ref **to_fetch)
 539 {
 540         struct helper_data *data = transport->data;
 541         int i, count;
 542
 543         if (process_connect(transport, 0)) {
 544                 do_take_over(transport);
 545                 return transport->fetch(transport, nr_heads, to_fetch);
 546         }
 547
 548         count = 0;
 549         for (i = 0; i < nr_heads; i++)
 550                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 551                         count++;
 552
 553         if (!count)
 554                 return 0;
 555
 556         if (data->fetch)
 557                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 558
 559         if (data->import)
 560                 return fetch_with_import(transport, nr_heads, to_fetch);
 561
 562         return -1;
 563 }
 564
 565 static void push_update_ref_status(struct strbuf *buf,
 566                                    struct ref **ref,
 567                                    struct ref *remote_refs)
 568 {
 569         char *refname, *msg;
 570         int status;
 571
 572         if (!prefixcmp(buf->buf, "ok ")) {
 573                 status = REF_STATUS_OK;
 574                 refname = buf->buf + 3;
 575         } else if (!prefixcmp(buf->buf, "error ")) {
 576                 status = REF_STATUS_REMOTE_REJECT;
 577                 refname = buf->buf + 6;
 578         } else
 579                 die("expected ok/error, helper said '%s'\n", buf->buf);
 580
 581         msg = strchr(refname, ' ');
 582         if (msg) {
 583                 struct strbuf msg_buf = STRBUF_INIT;
 584                 const char *end;
 585
 586                 *msg++ = '\0';
 587                 if (!unquote_c_style(&msg_buf, msg, &end))
 588                         msg = strbuf_detach(&msg_buf, NULL);
 589                 else
 590                         msg = xstrdup(msg);
 591                 strbuf_release(&msg_buf);
 592
 593                 if (!strcmp(msg, "no match")) {
 594                         status = REF_STATUS_NONE;
 595                         free(msg);
 596                         msg = NULL;
 597                 }
 598                 else if (!strcmp(msg, "up to date")) {
 599                         status = REF_STATUS_UPTODATE;
 600                         free(msg);
 601                         msg = NULL;
 602                 }
 603                 else if (!strcmp(msg, "non-fast forward")) {
 604                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 605                         free(msg);
 606                         msg = NULL;
 607                 }
 608         }
 609
 610         if (*ref)
 611                 *ref = find_ref_by_name(*ref, refname);
 612         if (!*ref)
 613                 *ref = find_ref_by_name(remote_refs, refname);
 614         if (!*ref) {
 615                 warning("helper reported unexpected status of %s", refname);
 616                 return;
 617         }
 618
 619         if ((*ref)->status != REF_STATUS_NONE) {
 620                 /*
 621                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 622                  * status reported by the remote helper if the latter is 'no match'.
 623                  */
 624                 if (status == REF_STATUS_NONE)
 625                         return;
 626         }
 627
 628         (*ref)->status = status;
 629         (*ref)->remote_status = msg;
 630 }
 631
 632 static void push_update_refs_status(struct helper_data *data,
 633                                     struct ref *remote_refs)
 634 {
 635         struct strbuf buf = STRBUF_INIT;
 636         struct ref *ref = remote_refs;
 637         for (;;) {
 638                 recvline(data, &buf);
 639                 if (!buf.len)
 640                         break;
 641
 642                 push_update_ref_status(&buf, &ref, remote_refs);
 643         }
 644         strbuf_release(&buf);
 645 }
 646
 647 static int push_refs_with_push(struct transport *transport,
 648                 struct ref *remote_refs, int flags)
 649 {
 650         int force_all = flags & TRANSPORT_PUSH_FORCE;
 651         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 652         struct helper_data *data = transport->data;
 653         struct strbuf buf = STRBUF_INIT;
 654         struct ref *ref;
 655
 656         get_helper(transport);
 657         if (!data->push)
 658                 return 1;
 659
 660         for (ref = remote_refs; ref; ref = ref->next) {
 661                 if (!ref->peer_ref && !mirror)
 662                         continue;
 663
 664                 /* Check for statuses set by set_ref_status_for_push() */
 665                 switch (ref->status) {
 666                 case REF_STATUS_REJECT_NONFASTFORWARD:
 667                 case REF_STATUS_UPTODATE:
 668                         continue;
 669                 default:
 670                         ; /* do nothing */
 671                 }
 672
 673                 if (force_all)
 674                         ref->force = 1;
 675
 676                 strbuf_addstr(&buf, "push ");
 677                 if (!ref->deletion) {
 678                         if (ref->force)
 679                                 strbuf_addch(&buf, '+');
 680                         if (ref->peer_ref)
 681                                 strbuf_addstr(&buf, ref->peer_ref->name);
 682                         else
 683                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 684                 }
 685                 strbuf_addch(&buf, ':');
 686                 strbuf_addstr(&buf, ref->name);
 687                 strbuf_addch(&buf, '\n');
 688         }
 689         if (buf.len == 0)
 690                 return 0;
 691
 692         standard_options(transport);
 693
 694         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 695                 if (set_helper_option(transport, "dry-run", "true") != 0)
 696                         die("helper %s does not support dry-run", data->name);
 697         }
 698
 699         strbuf_addch(&buf, '\n');
 700         sendline(data, &buf);
 701         strbuf_release(&buf);
 702
 703         push_update_refs_status(data, remote_refs);
 704         return 0;
 705 }
 706
 707 static int push_refs_with_export(struct transport *transport,
 708                 struct ref *remote_refs, int flags)
 709 {
 710         struct ref *ref;
 711         struct child_process *helper, exporter;
 712         struct helper_data *data = transport->data;
 713         char *export_marks = NULL, *import_marks = NULL;
 714         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 715         struct strbuf buf = STRBUF_INIT;
 716
 717         helper = get_helper(transport);
 718
 719         write_constant(helper->in, "export\n");
 720
 721         recvline(data, &buf);
 722         if (debug)
 723                 fprintf(stderr, "Debug: Got export_marks '%s'\n", buf.buf);
 724         if (buf.len) {
 725                 struct strbuf arg = STRBUF_INIT;
 726                 strbuf_addstr(&arg, "--export-marks=");
 727                 strbuf_addbuf(&arg, &buf);
 728                 export_marks = strbuf_detach(&arg, NULL);
 729         }
 730
 731         recvline(data, &buf);
 732         if (debug)
 733                 fprintf(stderr, "Debug: Got import_marks '%s'\n", buf.buf);
 734         if (buf.len) {
 735                 struct strbuf arg = STRBUF_INIT;
 736                 strbuf_addstr(&arg, "--import-marks=");
 737                 strbuf_addbuf(&arg, &buf);
 738                 import_marks = strbuf_detach(&arg, NULL);
 739         }
 740
 741         strbuf_reset(&buf);
 742
 743         for (ref = remote_refs; ref; ref = ref->next) {
 744                 char *private;
 745                 unsigned char sha1[20];
 746
 747                 if (!data->refspecs)
 748                         continue;
 749                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 750                 if (private && !get_sha1(private, sha1)) {
 751                         strbuf_addf(&buf, "^%s", private);
 752                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 753                 }
 754                 free(private);
 755
 756                 if (ref->peer_ref)
 757                         string_list_append(&revlist_args, ref->peer_ref->name);
 758
 759         }
 760
 761         if (get_exporter(transport, &exporter,
 762                          export_marks, import_marks, &revlist_args))
 763                 die("Couldn't run fast-export");
 764
 765         if (finish_command(&exporter))
 766                 die("Error while running fast-export");
 767         return 0;
 768 }
 769
 770 static int push_refs(struct transport *transport,
 771                 struct ref *remote_refs, int flags)
 772 {
 773         struct helper_data *data = transport->data;
 774
 775         if (process_connect(transport, 1)) {
 776                 do_take_over(transport);
 777                 return transport->push_refs(transport, remote_refs, flags);
 778         }
 779
 780         if (!remote_refs) {
 781                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 782                         "Perhaps you should specify a branch such as 'master'.\n");
 783                 return 0;
 784         }
 785
 786         if (data->push)
 787                 return push_refs_with_push(transport, remote_refs, flags);
 788
 789         if (data->export)
 790                 return push_refs_with_export(transport, remote_refs, flags);
 791
 792         return -1;
 793 }
 794
 795
 796 static int has_attribute(const char *attrs, const char *attr) {
 797         int len;
 798         if (!attrs)
 799                 return 0;
 800
 801         len = strlen(attr);
 802         for (;;) {
 803                 const char *space = strchrnul(attrs, ' ');
 804                 if (len == space - attrs && !strncmp(attrs, attr, len))
 805                         return 1;
 806                 if (!*space)
 807                         return 0;
 808                 attrs = space + 1;
 809         }
 810 }
 811
 812 static struct ref *get_refs_list(struct transport *transport, int for_push)
 813 {
 814         struct helper_data *data = transport->data;
 815         struct child_process *helper;
 816         struct ref *ret = NULL;
 817         struct ref **tail = &ret;
 818         struct ref *posn;
 819         struct strbuf buf = STRBUF_INIT;
 820
 821         helper = get_helper(transport);
 822
 823         if (process_connect(transport, for_push)) {
 824                 do_take_over(transport);
 825                 return transport->get_refs_list(transport, for_push);
 826         }
 827
 828         if (data->push && for_push)
 829                 write_str_in_full(helper->in, "list for-push\n");
 830         else
 831                 write_str_in_full(helper->in, "list\n");
 832
 833         while (1) {
 834                 char *eov, *eon;
 835                 recvline(data, &buf);
 836
 837                 if (!*buf.buf)
 838                         break;
 839
 840                 eov = strchr(buf.buf, ' ');
 841                 if (!eov)
 842                         die("Malformed response in ref list: %s", buf.buf);
 843                 eon = strchr(eov + 1, ' ');
 844                 *eov = '\0';
 845                 if (eon)
 846                         *eon = '\0';
 847                 *tail = alloc_ref(eov + 1);
 848                 if (buf.buf[0] == '@')
 849                         (*tail)->symref = xstrdup(buf.buf + 1);
 850                 else if (buf.buf[0] != '?')
 851                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 852                 if (eon) {
 853                         if (has_attribute(eon + 1, "unchanged")) {
 854                                 (*tail)->status |= REF_STATUS_UPTODATE;
 855                                 read_ref((*tail)->name, (*tail)->old_sha1);
 856                         }
 857                 }
 858                 tail = &((*tail)->next);
 859         }
 860         if (debug)
 861                 fprintf(stderr, "Debug: Read ref listing.\n");
 862         strbuf_release(&buf);
 863
 864         for (posn = ret; posn; posn = posn->next)
 865                 resolve_remote_symref(posn, ret);
 866
 867         return ret;
 868 }
 869
 870 int transport_helper_init(struct transport *transport, const char *name)
 871 {
 872         struct helper_data *data = xcalloc(sizeof(*data), 1);
 873         data->name = name;
 874
 875         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 876                 debug = 1;
 877
 878         transport->data = data;
 879         transport->set_option = set_helper_option;
 880         transport->get_refs_list = get_refs_list;
 881         transport->fetch = fetch;
 882         transport->push_refs = push_refs;
 883         transport->disconnect = release_helper;
 884         transport->connect = connect_helper;
 885         transport->smart_options = &(data->transport_options);
 886         return 0;
 887 }
 888
 889 /*
 890  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 891  * buffer less), so attempt reads and writes with up to that size.
 892  */
 893 #define BUFFERSIZE 65536
 894 /* This should be enough to hold debugging message. */
 895 #define PBUFFERSIZE 8192
 896
 897 /* Print bidirectional transfer loop debug message. */
 898 static void transfer_debug(const char *fmt, ...)
 899 {
 900         va_list args;
 901         char msgbuf[PBUFFERSIZE];
 902         static int debug_enabled = -1;
 903
 904         if (debug_enabled < 0)
 905                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 906         if (!debug_enabled)
 907                 return;
 908
 909         va_start(args, fmt);
 910         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 911         va_end(args);
 912         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 913 }
 914
 915 /* Stream state: More data may be coming in this direction. */
 916 #define SSTATE_TRANSFERING 0
 917 /*
 918  * Stream state: No more data coming in this direction, flushing rest of
 919  * data.
 920  */
 921 #define SSTATE_FLUSHING 1
 922 /* Stream state: Transfer in this direction finished. */
 923 #define SSTATE_FINISHED 2
 924
 925 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 926 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 927 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 928
 929 /* Unidirectional transfer. */
 930 struct unidirectional_transfer {
 931         /* Source */
 932         int src;
 933         /* Destination */
 934         int dest;
 935         /* Is source socket? */
 936         int src_is_sock;
 937         /* Is destination socket? */
 938         int dest_is_sock;
 939         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 940         int state;
 941         /* Buffer. */
 942         char buf[BUFFERSIZE];
 943         /* Buffer used. */
 944         size_t bufuse;
 945         /* Name of source. */
 946         const char *src_name;
 947         /* Name of destination. */
 948         const char *dest_name;
 949 };
 950
 951 /* Closes the target (for writing) if transfer has finished. */
 952 static void udt_close_if_finished(struct unidirectional_transfer *t)
 953 {
 954         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 955                 t->state = SSTATE_FINISHED;
 956                 if (t->dest_is_sock)
 957                         shutdown(t->dest, SHUT_WR);
 958                 else
 959                         close(t->dest);
 960                 transfer_debug("Closed %s.", t->dest_name);
 961         }
 962 }
 963
 964 /*
 965  * Tries to read read data from source into buffer. If buffer is full,
 966  * no data is read. Returns 0 on success, -1 on error.
 967  */
 968 static int udt_do_read(struct unidirectional_transfer *t)
 969 {
 970         ssize_t bytes;
 971
 972         if (t->bufuse == BUFFERSIZE)
 973                 return 0;       /* No space for more. */
 974
 975         transfer_debug("%s is readable", t->src_name);
 976         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 977         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 978                 errno != EINTR) {
 979                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 980                 return -1;
 981         } else if (bytes == 0) {
 982                 transfer_debug("%s EOF (with %i bytes in buffer)",
 983                         t->src_name, t->bufuse);
 984                 t->state = SSTATE_FLUSHING;
 985         } else if (bytes > 0) {
 986                 t->bufuse += bytes;
 987                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 988                         (int)bytes, t->src_name, (int)t->bufuse);
 989         }
 990         return 0;
 991 }
 992
 993 /* Tries to write data from buffer into destination. If buffer is empty,
 994  * no data is written. Returns 0 on success, -1 on error.
 995  */
 996 static int udt_do_write(struct unidirectional_transfer *t)
 997 {
 998         ssize_t bytes;
 999
1000         if (t->bufuse == 0)
1001                 return 0;       /* Nothing to write. */
1002
1003         transfer_debug("%s is writable", t->dest_name);
1004         bytes = write(t->dest, t->buf, t->bufuse);
1005         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1006                 errno != EINTR) {
1007                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1008                 return -1;
1009         } else if (bytes > 0) {
1010                 t->bufuse -= bytes;
1011                 if (t->bufuse)
1012                         memmove(t->buf, t->buf + bytes, t->bufuse);
1013                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1014                         (int)bytes, t->dest_name, (int)t->bufuse);
1015         }
1016         return 0;
1017 }
1018
1019
1020 /* State of bidirectional transfer loop. */
1021 struct bidirectional_transfer_state {
1022         /* Direction from program to git. */
1023         struct unidirectional_transfer ptg;
1024         /* Direction from git to program. */
1025         struct unidirectional_transfer gtp;
1026 };
1027
1028 static void *udt_copy_task_routine(void *udt)
1029 {
1030         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1031         while (t->state != SSTATE_FINISHED) {
1032                 if (STATE_NEEDS_READING(t->state))
1033                         if (udt_do_read(t))
1034                                 return NULL;
1035                 if (STATE_NEEDS_WRITING(t->state))
1036                         if (udt_do_write(t))
1037                                 return NULL;
1038                 if (STATE_NEEDS_CLOSING(t->state))
1039                         udt_close_if_finished(t);
1040         }
1041         return udt;     /* Just some non-NULL value. */
1042 }
1043
1044 #ifndef NO_PTHREADS
1045
1046 /*
1047  * Join thread, with apporiate errors on failure. Name is name for the
1048  * thread (for error messages). Returns 0 on success, 1 on failure.
1049  */
1050 static int tloop_join(pthread_t thread, const char *name)
1051 {
1052         int err;
1053         void *tret;
1054         err = pthread_join(thread, &tret);
1055         if (!tret) {
1056                 error("%s thread failed", name);
1057                 return 1;
1058         }
1059         if (err) {
1060                 error("%s thread failed to join: %s", name, strerror(err));
1061                 return 1;
1062         }
1063         return 0;
1064 }
1065
1066 /*
1067  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1068  * -1 on failure.
1069  */
1070 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1071 {
1072         pthread_t gtp_thread;
1073         pthread_t ptg_thread;
1074         int err;
1075         int ret = 0;
1076         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1077                 &s->gtp);
1078         if (err)
1079                 die("Can't start thread for copying data: %s", strerror(err));
1080         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1081                 &s->ptg);
1082         if (err)
1083                 die("Can't start thread for copying data: %s", strerror(err));
1084
1085         ret |= tloop_join(gtp_thread, "Git to program copy");
1086         ret |= tloop_join(ptg_thread, "Program to git copy");
1087         return ret;
1088 }
1089 #else
1090
1091 /* Close the source and target (for writing) for transfer. */
1092 static void udt_kill_transfer(struct unidirectional_transfer *t)
1093 {
1094         t->state = SSTATE_FINISHED;
1095         /*
1096          * Socket read end left open isn't a disaster if nobody
1097          * attempts to read from it (mingw compat headers do not
1098          * have SHUT_RD)...
1099          *
1100          * We can't fully close the socket since otherwise gtp
1101          * task would first close the socket it sends data to
1102          * while closing the ptg file descriptors.
1103          */
1104         if (!t->src_is_sock)
1105                 close(t->src);
1106         if (t->dest_is_sock)
1107                 shutdown(t->dest, SHUT_WR);
1108         else
1109                 close(t->dest);
1110 }
1111
1112 /*
1113  * Join process, with apporiate errors on failure. Name is name for the
1114  * process (for error messages). Returns 0 on success, 1 on failure.
1115  */
1116 static int tloop_join(pid_t pid, const char *name)
1117 {
1118         int tret;
1119         if (waitpid(pid, &tret, 0) < 0) {
1120                 error("%s process failed to wait: %s", name, strerror(errno));
1121                 return 1;
1122         }
1123         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1124                 error("%s process failed", name);
1125                 return 1;
1126         }
1127         return 0;
1128 }
1129
1130 /*
1131  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1132  * -1 on failure.
1133  */
1134 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1135 {
1136         pid_t pid1, pid2;
1137         int ret = 0;
1138
1139         /* Fork thread #1: git to program. */
1140         pid1 = fork();
1141         if (pid1 < 0)
1142                 die_errno("Can't start thread for copying data");
1143         else if (pid1 == 0) {
1144                 udt_kill_transfer(&s->ptg);
1145                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1146         }
1147
1148         /* Fork thread #2: program to git. */
1149         pid2 = fork();
1150         if (pid2 < 0)
1151                 die_errno("Can't start thread for copying data");
1152         else if (pid2 == 0) {
1153                 udt_kill_transfer(&s->gtp);
1154                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1155         }
1156
1157         /*
1158          * Close both streams in parent as to not interfere with
1159          * end of file detection and wait for both tasks to finish.
1160          */
1161         udt_kill_transfer(&s->gtp);
1162         udt_kill_transfer(&s->ptg);
1163         ret |= tloop_join(pid1, "Git to program copy");
1164         ret |= tloop_join(pid2, "Program to git copy");
1165         return ret;
1166 }
1167 #endif
1168
1169 /*
1170  * Copies data from stdin to output and from input to stdout simultaneously.
1171  * Additionally filtering through given filter. If filter is NULL, uses
1172  * identity filter.
1173  */
1174 int bidirectional_transfer_loop(int input, int output)
1175 {
1176         struct bidirectional_transfer_state state;
1177
1178         /* Fill the state fields. */
1179         state.ptg.src = input;
1180         state.ptg.dest = 1;
1181         state.ptg.src_is_sock = (input == output);
1182         state.ptg.dest_is_sock = 0;
1183         state.ptg.state = SSTATE_TRANSFERING;
1184         state.ptg.bufuse = 0;
1185         state.ptg.src_name = "remote input";
1186         state.ptg.dest_name = "stdout";
1187
1188         state.gtp.src = 0;
1189         state.gtp.dest = output;
1190         state.gtp.src_is_sock = 0;
1191         state.gtp.dest_is_sock = (input == output);
1192         state.gtp.state = SSTATE_TRANSFERING;
1193         state.gtp.bufuse = 0;
1194         state.gtp.src_name = "stdin";
1195         state.gtp.dest_name = "remote output";
1196
1197         return tloop_spawnwait_tasks(&state);
1198 }