git.oblomov.eu Git - git/blob - transport-helper.c

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "quote.h"
   9 #include "remote.h"
  10 #include "string-list.h"
  11 #include "thread-utils.h"
  12
  13 static int debug;
  14
  15 struct helper_data
  16 {
  17         const char *name;
  18         struct child_process *helper;
  19         FILE *out;
  20         unsigned fetch : 1,
  21                 import : 1,
  22                 export : 1,
  23                 option : 1,
  24                 push : 1,
  25                 connect : 1,
  26                 no_disconnect_req : 1;
  27         /* These go from remote name (as in "list") to private name */
  28         struct refspec *refspecs;
  29         int refspec_nr;
  30         /* Transport options for fetch-pack/send-pack (should one of
  31          * those be invoked).
  32          */
  33         struct git_transport_options transport_options;
  34 };
  35
  36 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  37 {
  38         if (debug)
  39                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  40         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  41                 != buffer->len)
  42                 die_errno("Full write to remote helper failed");
  43 }
  44
  45 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  46 {
  47         strbuf_reset(buffer);
  48         if (debug)
  49                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  50         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  51                 if (debug)
  52                         fprintf(stderr, "Debug: Remote helper quit.\n");
  53                 exit(128);
  54         }
  55
  56         if (debug)
  57                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  58         return 0;
  59 }
  60
  61 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  62 {
  63         return recvline_fh(helper->out, buffer);
  64 }
  65
  66 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  67 {
  68         sendline(helper, buffer);
  69         recvline(helper, buffer);
  70 }
  71
  72 static void write_constant(int fd, const char *str)
  73 {
  74         if (debug)
  75                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  76         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  77                 die_errno("Full write to remote helper failed");
  78 }
  79
  80 const char *remove_ext_force(const char *url)
  81 {
  82         if (url) {
  83                 const char *colon = strchr(url, ':');
  84                 if (colon && colon[1] == ':')
  85                         return colon + 2;
  86         }
  87         return url;
  88 }
  89
  90 static void do_take_over(struct transport *transport)
  91 {
  92         struct helper_data *data;
  93         data = (struct helper_data *)transport->data;
  94         transport_take_over(transport, data->helper);
  95         fclose(data->out);
  96         free(data);
  97 }
  98
  99 static struct child_process *get_helper(struct transport *transport)
 100 {
 101         struct helper_data *data = transport->data;
 102         struct strbuf buf = STRBUF_INIT;
 103         struct child_process *helper;
 104         const char **refspecs = NULL;
 105         int refspec_nr = 0;
 106         int refspec_alloc = 0;
 107         int duped;
 108         int code;
 109
 110         if (data->helper)
 111                 return data->helper;
 112
 113         helper = xcalloc(1, sizeof(*helper));
 114         helper->in = -1;
 115         helper->out = -1;
 116         helper->err = 0;
 117         helper->argv = xcalloc(4, sizeof(*helper->argv));
 118         strbuf_addf(&buf, "git-remote-%s", data->name);
 119         helper->argv[0] = strbuf_detach(&buf, NULL);
 120         helper->argv[1] = transport->remote->name;
 121         helper->argv[2] = remove_ext_force(transport->url);
 122         helper->git_cmd = 0;
 123         helper->silent_exec_failure = 1;
 124         code = start_command(helper);
 125         if (code < 0 && errno == ENOENT)
 126                 die("Unable to find remote helper for '%s'", data->name);
 127         else if (code != 0)
 128                 exit(code);
 129
 130         data->helper = helper;
 131         data->no_disconnect_req = 0;
 132
 133         /*
 134          * Open the output as FILE* so strbuf_getline() can be used.
 135          * Do this with duped fd because fclose() will close the fd,
 136          * and stuff like taking over will require the fd to remain.
 137          */
 138         duped = dup(helper->out);
 139         if (duped < 0)
 140                 die_errno("Can't dup helper output fd");
 141         data->out = xfdopen(duped, "r");
 142
 143         write_constant(helper->in, "capabilities\n");
 144
 145         while (1) {
 146                 const char *capname;
 147                 int mandatory = 0;
 148                 recvline(data, &buf);
 149
 150                 if (!*buf.buf)
 151                         break;
 152
 153                 if (*buf.buf == '*') {
 154                         capname = buf.buf + 1;
 155                         mandatory = 1;
 156                 } else
 157                         capname = buf.buf;
 158
 159                 if (debug)
 160                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 161                 if (!strcmp(capname, "fetch"))
 162                         data->fetch = 1;
 163                 else if (!strcmp(capname, "option"))
 164                         data->option = 1;
 165                 else if (!strcmp(capname, "push"))
 166                         data->push = 1;
 167                 else if (!strcmp(capname, "import"))
 168                         data->import = 1;
 169                 else if (!strcmp(capname, "export"))
 170                         data->export = 1;
 171                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 172                         ALLOC_GROW(refspecs,
 173                                    refspec_nr + 1,
 174                                    refspec_alloc);
 175                         refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
 176                 } else if (!strcmp(capname, "connect")) {
 177                         data->connect = 1;
 178                 } else if (!strcmp(buf.buf, "gitdir")) {
 179                         struct strbuf gitdir = STRBUF_INIT;
 180                         strbuf_addf(&gitdir, "gitdir %s\n", get_git_dir());
 181                         sendline(data, &gitdir);
 182                         strbuf_release(&gitdir);
 183                 } else if (mandatory) {
 184                         die("Unknown mandatory capability %s. This remote "
 185                             "helper probably needs newer version of Git.\n",
 186                             capname);
 187                 }
 188         }
 189         if (refspecs) {
 190                 int i;
 191                 data->refspec_nr = refspec_nr;
 192                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 193                 for (i = 0; i < refspec_nr; i++) {
 194                         free((char *)refspecs[i]);
 195                 }
 196                 free(refspecs);
 197         }
 198         strbuf_release(&buf);
 199         if (debug)
 200                 fprintf(stderr, "Debug: Capabilities complete.\n");
 201         return data->helper;
 202 }
 203
 204 static int disconnect_helper(struct transport *transport)
 205 {
 206         struct helper_data *data = transport->data;
 207         struct strbuf buf = STRBUF_INIT;
 208
 209         if (data->helper) {
 210                 if (debug)
 211                         fprintf(stderr, "Debug: Disconnecting.\n");
 212                 if (!data->no_disconnect_req) {
 213                         strbuf_addf(&buf, "\n");
 214                         sendline(data, &buf);
 215                 }
 216                 close(data->helper->in);
 217                 close(data->helper->out);
 218                 fclose(data->out);
 219                 finish_command(data->helper);
 220                 free((char *)data->helper->argv[0]);
 221                 free(data->helper->argv);
 222                 free(data->helper);
 223                 data->helper = NULL;
 224         }
 225         return 0;
 226 }
 227
 228 static const char *unsupported_options[] = {
 229         TRANS_OPT_UPLOADPACK,
 230         TRANS_OPT_RECEIVEPACK,
 231         TRANS_OPT_THIN,
 232         TRANS_OPT_KEEP
 233         };
 234 static const char *boolean_options[] = {
 235         TRANS_OPT_THIN,
 236         TRANS_OPT_KEEP,
 237         TRANS_OPT_FOLLOWTAGS
 238         };
 239
 240 static int set_helper_option(struct transport *transport,
 241                           const char *name, const char *value)
 242 {
 243         struct helper_data *data = transport->data;
 244         struct strbuf buf = STRBUF_INIT;
 245         int i, ret, is_bool = 0;
 246
 247         get_helper(transport);
 248
 249         if (!data->option)
 250                 return 1;
 251
 252         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 253                 if (!strcmp(name, unsupported_options[i]))
 254                         return 1;
 255         }
 256
 257         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 258                 if (!strcmp(name, boolean_options[i])) {
 259                         is_bool = 1;
 260                         break;
 261                 }
 262         }
 263
 264         strbuf_addf(&buf, "option %s ", name);
 265         if (is_bool)
 266                 strbuf_addstr(&buf, value ? "true" : "false");
 267         else
 268                 quote_c_style(value, &buf, NULL, 0);
 269         strbuf_addch(&buf, '\n');
 270
 271         xchgline(data, &buf);
 272
 273         if (!strcmp(buf.buf, "ok"))
 274                 ret = 0;
 275         else if (!prefixcmp(buf.buf, "error")) {
 276                 ret = -1;
 277         } else if (!strcmp(buf.buf, "unsupported"))
 278                 ret = 1;
 279         else {
 280                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 281                 ret = 1;
 282         }
 283         strbuf_release(&buf);
 284         return ret;
 285 }
 286
 287 static void standard_options(struct transport *t)
 288 {
 289         char buf[16];
 290         int n;
 291         int v = t->verbose;
 292
 293         set_helper_option(t, "progress", t->progress ? "true" : "false");
 294
 295         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 296         if (n >= sizeof(buf))
 297                 die("impossibly large verbosity value");
 298         set_helper_option(t, "verbosity", buf);
 299 }
 300
 301 static int release_helper(struct transport *transport)
 302 {
 303         struct helper_data *data = transport->data;
 304         free_refspec(data->refspec_nr, data->refspecs);
 305         data->refspecs = NULL;
 306         disconnect_helper(transport);
 307         free(transport->data);
 308         return 0;
 309 }
 310
 311 static int fetch_with_fetch(struct transport *transport,
 312                             int nr_heads, struct ref **to_fetch)
 313 {
 314         struct helper_data *data = transport->data;
 315         int i;
 316         struct strbuf buf = STRBUF_INIT;
 317
 318         standard_options(transport);
 319
 320         for (i = 0; i < nr_heads; i++) {
 321                 const struct ref *posn = to_fetch[i];
 322                 if (posn->status & REF_STATUS_UPTODATE)
 323                         continue;
 324
 325                 strbuf_addf(&buf, "fetch %s %s\n",
 326                             sha1_to_hex(posn->old_sha1), posn->name);
 327         }
 328
 329         strbuf_addch(&buf, '\n');
 330         sendline(data, &buf);
 331
 332         while (1) {
 333                 recvline(data, &buf);
 334
 335                 if (!prefixcmp(buf.buf, "lock ")) {
 336                         const char *name = buf.buf + 5;
 337                         if (transport->pack_lockfile)
 338                                 warning("%s also locked %s", data->name, name);
 339                         else
 340                                 transport->pack_lockfile = xstrdup(name);
 341                 }
 342                 else if (!buf.len)
 343                         break;
 344                 else
 345                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 346         }
 347         strbuf_release(&buf);
 348         return 0;
 349 }
 350
 351 static int get_importer(struct transport *transport, struct child_process *fastimport)
 352 {
 353         struct child_process *helper = get_helper(transport);
 354         memset(fastimport, 0, sizeof(*fastimport));
 355         fastimport->in = helper->out;
 356         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 357         fastimport->argv[0] = "fast-import";
 358         fastimport->argv[1] = "--quiet";
 359
 360         fastimport->git_cmd = 1;
 361         return start_command(fastimport);
 362 }
 363
 364 static int get_exporter(struct transport *transport,
 365                         struct child_process *fastexport,
 366                         const char *export_marks,
 367                         const char *import_marks,
 368                         struct string_list *revlist_args)
 369 {
 370         struct child_process *helper = get_helper(transport);
 371         int argc = 0, i;
 372         memset(fastexport, 0, sizeof(*fastexport));
 373
 374         /* we need to duplicate helper->in because we want to use it after
 375          * fastexport is done with it. */
 376         fastexport->out = dup(helper->in);
 377         fastexport->argv = xcalloc(4 + revlist_args->nr, sizeof(*fastexport->argv));
 378         fastexport->argv[argc++] = "fast-export";
 379         if (export_marks)
 380                 fastexport->argv[argc++] = export_marks;
 381         if (import_marks)
 382                 fastexport->argv[argc++] = import_marks;
 383
 384         for (i = 0; i < revlist_args->nr; i++)
 385                 fastexport->argv[argc++] = revlist_args->items[i].string;
 386
 387         fastexport->git_cmd = 1;
 388         return start_command(fastexport);
 389 }
 390
 391 static int fetch_with_import(struct transport *transport,
 392                              int nr_heads, struct ref **to_fetch)
 393 {
 394         struct child_process fastimport;
 395         struct helper_data *data = transport->data;
 396         int i;
 397         struct ref *posn;
 398         struct strbuf buf = STRBUF_INIT;
 399
 400         get_helper(transport);
 401
 402         if (get_importer(transport, &fastimport))
 403                 die("Couldn't run fast-import");
 404
 405         for (i = 0; i < nr_heads; i++) {
 406                 posn = to_fetch[i];
 407                 if (posn->status & REF_STATUS_UPTODATE)
 408                         continue;
 409
 410                 strbuf_addf(&buf, "import %s\n", posn->name);
 411                 sendline(data, &buf);
 412                 strbuf_reset(&buf);
 413         }
 414         disconnect_helper(transport);
 415         finish_command(&fastimport);
 416         free(fastimport.argv);
 417         fastimport.argv = NULL;
 418
 419         for (i = 0; i < nr_heads; i++) {
 420                 char *private;
 421                 posn = to_fetch[i];
 422                 if (posn->status & REF_STATUS_UPTODATE)
 423                         continue;
 424                 if (data->refspecs)
 425                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 426                 else
 427                         private = strdup(posn->name);
 428                 read_ref(private, posn->old_sha1);
 429                 free(private);
 430         }
 431         strbuf_release(&buf);
 432         return 0;
 433 }
 434
 435 static int process_connect_service(struct transport *transport,
 436                                    const char *name, const char *exec)
 437 {
 438         struct helper_data *data = transport->data;
 439         struct strbuf cmdbuf = STRBUF_INIT;
 440         struct child_process *helper;
 441         int r, duped, ret = 0;
 442         FILE *input;
 443
 444         helper = get_helper(transport);
 445
 446         /*
 447          * Yes, dup the pipe another time, as we need unbuffered version
 448          * of input pipe as FILE*. fclose() closes the underlying fd and
 449          * stream buffering only can be changed before first I/O operation
 450          * on it.
 451          */
 452         duped = dup(helper->out);
 453         if (duped < 0)
 454                 die_errno("Can't dup helper output fd");
 455         input = xfdopen(duped, "r");
 456         setvbuf(input, NULL, _IONBF, 0);
 457
 458         /*
 459          * Handle --upload-pack and friends. This is fire and forget...
 460          * just warn if it fails.
 461          */
 462         if (strcmp(name, exec)) {
 463                 r = set_helper_option(transport, "servpath", exec);
 464                 if (r > 0)
 465                         warning("Setting remote service path not supported by protocol.");
 466                 else if (r < 0)
 467                         warning("Invalid remote service path.");
 468         }
 469
 470         if (data->connect)
 471                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 472         else
 473                 goto exit;
 474
 475         sendline(data, &cmdbuf);
 476         recvline_fh(input, &cmdbuf);
 477         if (!strcmp(cmdbuf.buf, "")) {
 478                 data->no_disconnect_req = 1;
 479                 if (debug)
 480                         fprintf(stderr, "Debug: Smart transport connection "
 481                                 "ready.\n");
 482                 ret = 1;
 483         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 484                 if (debug)
 485                         fprintf(stderr, "Debug: Falling back to dumb "
 486                                 "transport.\n");
 487         } else
 488                 die("Unknown response to connect: %s",
 489                         cmdbuf.buf);
 490
 491 exit:
 492         fclose(input);
 493         return ret;
 494 }
 495
 496 static int process_connect(struct transport *transport,
 497                                      int for_push)
 498 {
 499         struct helper_data *data = transport->data;
 500         const char *name;
 501         const char *exec;
 502
 503         name = for_push ? "git-receive-pack" : "git-upload-pack";
 504         if (for_push)
 505                 exec = data->transport_options.receivepack;
 506         else
 507                 exec = data->transport_options.uploadpack;
 508
 509         return process_connect_service(transport, name, exec);
 510 }
 511
 512 static int connect_helper(struct transport *transport, const char *name,
 513                    const char *exec, int fd[2])
 514 {
 515         struct helper_data *data = transport->data;
 516
 517         /* Get_helper so connect is inited. */
 518         get_helper(transport);
 519         if (!data->connect)
 520                 die("Operation not supported by protocol.");
 521
 522         if (!process_connect_service(transport, name, exec))
 523                 die("Can't connect to subservice %s.", name);
 524
 525         fd[0] = data->helper->out;
 526         fd[1] = data->helper->in;
 527         return 0;
 528 }
 529
 530 static int fetch(struct transport *transport,
 531                  int nr_heads, struct ref **to_fetch)
 532 {
 533         struct helper_data *data = transport->data;
 534         int i, count;
 535
 536         if (process_connect(transport, 0)) {
 537                 do_take_over(transport);
 538                 return transport->fetch(transport, nr_heads, to_fetch);
 539         }
 540
 541         count = 0;
 542         for (i = 0; i < nr_heads; i++)
 543                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 544                         count++;
 545
 546         if (!count)
 547                 return 0;
 548
 549         if (data->fetch)
 550                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 551
 552         if (data->import)
 553                 return fetch_with_import(transport, nr_heads, to_fetch);
 554
 555         return -1;
 556 }
 557
 558 static int push_refs_with_push(struct transport *transport,
 559                 struct ref *remote_refs, int flags)
 560 {
 561         int force_all = flags & TRANSPORT_PUSH_FORCE;
 562         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 563         struct helper_data *data = transport->data;
 564         struct strbuf buf = STRBUF_INIT;
 565         struct child_process *helper;
 566         struct ref *ref;
 567
 568         helper = get_helper(transport);
 569         if (!data->push)
 570                 return 1;
 571
 572         for (ref = remote_refs; ref; ref = ref->next) {
 573                 if (!ref->peer_ref && !mirror)
 574                         continue;
 575
 576                 /* Check for statuses set by set_ref_status_for_push() */
 577                 switch (ref->status) {
 578                 case REF_STATUS_REJECT_NONFASTFORWARD:
 579                 case REF_STATUS_UPTODATE:
 580                         continue;
 581                 default:
 582                         ; /* do nothing */
 583                 }
 584
 585                 if (force_all)
 586                         ref->force = 1;
 587
 588                 strbuf_addstr(&buf, "push ");
 589                 if (!ref->deletion) {
 590                         if (ref->force)
 591                                 strbuf_addch(&buf, '+');
 592                         if (ref->peer_ref)
 593                                 strbuf_addstr(&buf, ref->peer_ref->name);
 594                         else
 595                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 596                 }
 597                 strbuf_addch(&buf, ':');
 598                 strbuf_addstr(&buf, ref->name);
 599                 strbuf_addch(&buf, '\n');
 600         }
 601         if (buf.len == 0)
 602                 return 0;
 603
 604         standard_options(transport);
 605
 606         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 607                 if (set_helper_option(transport, "dry-run", "true") != 0)
 608                         die("helper %s does not support dry-run", data->name);
 609         }
 610
 611         strbuf_addch(&buf, '\n');
 612         sendline(data, &buf);
 613
 614         ref = remote_refs;
 615         while (1) {
 616                 char *refname, *msg;
 617                 int status;
 618
 619                 recvline(data, &buf);
 620                 if (!buf.len)
 621                         break;
 622
 623                 if (!prefixcmp(buf.buf, "ok ")) {
 624                         status = REF_STATUS_OK;
 625                         refname = buf.buf + 3;
 626                 } else if (!prefixcmp(buf.buf, "error ")) {
 627                         status = REF_STATUS_REMOTE_REJECT;
 628                         refname = buf.buf + 6;
 629                 } else
 630                         die("expected ok/error, helper said '%s'\n", buf.buf);
 631
 632                 msg = strchr(refname, ' ');
 633                 if (msg) {
 634                         struct strbuf msg_buf = STRBUF_INIT;
 635                         const char *end;
 636
 637                         *msg++ = '\0';
 638                         if (!unquote_c_style(&msg_buf, msg, &end))
 639                                 msg = strbuf_detach(&msg_buf, NULL);
 640                         else
 641                                 msg = xstrdup(msg);
 642                         strbuf_release(&msg_buf);
 643
 644                         if (!strcmp(msg, "no match")) {
 645                                 status = REF_STATUS_NONE;
 646                                 free(msg);
 647                                 msg = NULL;
 648                         }
 649                         else if (!strcmp(msg, "up to date")) {
 650                                 status = REF_STATUS_UPTODATE;
 651                                 free(msg);
 652                                 msg = NULL;
 653                         }
 654                         else if (!strcmp(msg, "non-fast forward")) {
 655                                 status = REF_STATUS_REJECT_NONFASTFORWARD;
 656                                 free(msg);
 657                                 msg = NULL;
 658                         }
 659                 }
 660
 661                 if (ref)
 662                         ref = find_ref_by_name(ref, refname);
 663                 if (!ref)
 664                         ref = find_ref_by_name(remote_refs, refname);
 665                 if (!ref) {
 666                         warning("helper reported unexpected status of %s", refname);
 667                         continue;
 668                 }
 669
 670                 if (ref->status != REF_STATUS_NONE) {
 671                         /*
 672                          * Earlier, the ref was marked not to be pushed, so ignore the ref
 673                          * status reported by the remote helper if the latter is 'no match'.
 674                          */
 675                         if (status == REF_STATUS_NONE)
 676                                 continue;
 677                 }
 678
 679                 ref->status = status;
 680                 ref->remote_status = msg;
 681         }
 682         strbuf_release(&buf);
 683         return 0;
 684 }
 685
 686 static int push_refs_with_export(struct transport *transport,
 687                 struct ref *remote_refs, int flags)
 688 {
 689         struct ref *ref;
 690         struct child_process *helper, exporter;
 691         struct helper_data *data = transport->data;
 692         char *export_marks = NULL, *import_marks = NULL;
 693         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 694         struct strbuf buf = STRBUF_INIT;
 695
 696         helper = get_helper(transport);
 697
 698         write_constant(helper->in, "export\n");
 699
 700         recvline(data, &buf);
 701         if (debug)
 702                 fprintf(stderr, "Debug: Got export_marks '%s'\n", buf.buf);
 703         if (buf.len) {
 704                 struct strbuf arg = STRBUF_INIT;
 705                 strbuf_addstr(&arg, "--export-marks=");
 706                 strbuf_addbuf(&arg, &buf);
 707                 export_marks = strbuf_detach(&arg, NULL);
 708         }
 709
 710         recvline(data, &buf);
 711         if (debug)
 712                 fprintf(stderr, "Debug: Got import_marks '%s'\n", buf.buf);
 713         if (buf.len) {
 714                 struct strbuf arg = STRBUF_INIT;
 715                 strbuf_addstr(&arg, "--import-marks=");
 716                 strbuf_addbuf(&arg, &buf);
 717                 import_marks = strbuf_detach(&arg, NULL);
 718         }
 719
 720         strbuf_reset(&buf);
 721
 722         for (ref = remote_refs; ref; ref = ref->next) {
 723                 char *private;
 724                 unsigned char sha1[20];
 725
 726                 if (!data->refspecs)
 727                         continue;
 728                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 729                 if (private && !get_sha1(private, sha1)) {
 730                         strbuf_addf(&buf, "^%s", private);
 731                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 732                 }
 733
 734                 string_list_append(&revlist_args, ref->name);
 735
 736         }
 737
 738         if (get_exporter(transport, &exporter,
 739                          export_marks, import_marks, &revlist_args))
 740                 die("Couldn't run fast-export");
 741
 742         data->no_disconnect_req = 1;
 743         finish_command(&exporter);
 744         disconnect_helper(transport);
 745         return 0;
 746 }
 747
 748 static int push_refs(struct transport *transport,
 749                 struct ref *remote_refs, int flags)
 750 {
 751         struct helper_data *data = transport->data;
 752
 753         if (process_connect(transport, 1)) {
 754                 do_take_over(transport);
 755                 return transport->push_refs(transport, remote_refs, flags);
 756         }
 757
 758         if (!remote_refs) {
 759                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 760                         "Perhaps you should specify a branch such as 'master'.\n");
 761                 return 0;
 762         }
 763
 764         if (data->push)
 765                 return push_refs_with_push(transport, remote_refs, flags);
 766
 767         if (data->export)
 768                 return push_refs_with_export(transport, remote_refs, flags);
 769
 770         return -1;
 771 }
 772
 773
 774 static int has_attribute(const char *attrs, const char *attr) {
 775         int len;
 776         if (!attrs)
 777                 return 0;
 778
 779         len = strlen(attr);
 780         for (;;) {
 781                 const char *space = strchrnul(attrs, ' ');
 782                 if (len == space - attrs && !strncmp(attrs, attr, len))
 783                         return 1;
 784                 if (!*space)
 785                         return 0;
 786                 attrs = space + 1;
 787         }
 788 }
 789
 790 static struct ref *get_refs_list(struct transport *transport, int for_push)
 791 {
 792         struct helper_data *data = transport->data;
 793         struct child_process *helper;
 794         struct ref *ret = NULL;
 795         struct ref **tail = &ret;
 796         struct ref *posn;
 797         struct strbuf buf = STRBUF_INIT;
 798
 799         helper = get_helper(transport);
 800
 801         if (process_connect(transport, for_push)) {
 802                 do_take_over(transport);
 803                 return transport->get_refs_list(transport, for_push);
 804         }
 805
 806         if (data->push && for_push)
 807                 write_str_in_full(helper->in, "list for-push\n");
 808         else
 809                 write_str_in_full(helper->in, "list\n");
 810
 811         while (1) {
 812                 char *eov, *eon;
 813                 recvline(data, &buf);
 814
 815                 if (!*buf.buf)
 816                         break;
 817
 818                 eov = strchr(buf.buf, ' ');
 819                 if (!eov)
 820                         die("Malformed response in ref list: %s", buf.buf);
 821                 eon = strchr(eov + 1, ' ');
 822                 *eov = '\0';
 823                 if (eon)
 824                         *eon = '\0';
 825                 *tail = alloc_ref(eov + 1);
 826                 if (buf.buf[0] == '@')
 827                         (*tail)->symref = xstrdup(buf.buf + 1);
 828                 else if (buf.buf[0] != '?')
 829                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 830                 if (eon) {
 831                         if (has_attribute(eon + 1, "unchanged")) {
 832                                 (*tail)->status |= REF_STATUS_UPTODATE;
 833                                 read_ref((*tail)->name, (*tail)->old_sha1);
 834                         }
 835                 }
 836                 tail = &((*tail)->next);
 837         }
 838         if (debug)
 839                 fprintf(stderr, "Debug: Read ref listing.\n");
 840         strbuf_release(&buf);
 841
 842         for (posn = ret; posn; posn = posn->next)
 843                 resolve_remote_symref(posn, ret);
 844
 845         return ret;
 846 }
 847
 848 int transport_helper_init(struct transport *transport, const char *name)
 849 {
 850         struct helper_data *data = xcalloc(sizeof(*data), 1);
 851         data->name = name;
 852
 853         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 854                 debug = 1;
 855
 856         transport->data = data;
 857         transport->set_option = set_helper_option;
 858         transport->get_refs_list = get_refs_list;
 859         transport->fetch = fetch;
 860         transport->push_refs = push_refs;
 861         transport->disconnect = release_helper;
 862         transport->connect = connect_helper;
 863         transport->smart_options = &(data->transport_options);
 864         return 0;
 865 }
 866
 867 /*
 868  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 869  * buffer less), so attempt reads and writes with up to that size.
 870  */
 871 #define BUFFERSIZE 65536
 872 /* This should be enough to hold debugging message. */
 873 #define PBUFFERSIZE 8192
 874
 875 /* Print bidirectional transfer loop debug message. */
 876 static void transfer_debug(const char *fmt, ...)
 877 {
 878         va_list args;
 879         char msgbuf[PBUFFERSIZE];
 880         static int debug_enabled = -1;
 881
 882         if (debug_enabled < 0)
 883                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 884         if (!debug_enabled)
 885                 return;
 886
 887         va_start(args, fmt);
 888         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 889         va_end(args);
 890         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 891 }
 892
 893 /* Stream state: More data may be coming in this direction. */
 894 #define SSTATE_TRANSFERING 0
 895 /*
 896  * Stream state: No more data coming in this direction, flushing rest of
 897  * data.
 898  */
 899 #define SSTATE_FLUSHING 1
 900 /* Stream state: Transfer in this direction finished. */
 901 #define SSTATE_FINISHED 2
 902
 903 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 904 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 905 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 906
 907 /* Unidirectional transfer. */
 908 struct unidirectional_transfer {
 909         /* Source */
 910         int src;
 911         /* Destination */
 912         int dest;
 913         /* Is source socket? */
 914         int src_is_sock;
 915         /* Is destination socket? */
 916         int dest_is_sock;
 917         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 918         int state;
 919         /* Buffer. */
 920         char buf[BUFFERSIZE];
 921         /* Buffer used. */
 922         size_t bufuse;
 923         /* Name of source. */
 924         const char *src_name;
 925         /* Name of destination. */
 926         const char *dest_name;
 927 };
 928
 929 /* Closes the target (for writing) if transfer has finished. */
 930 static void udt_close_if_finished(struct unidirectional_transfer *t)
 931 {
 932         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 933                 t->state = SSTATE_FINISHED;
 934                 if (t->dest_is_sock)
 935                         shutdown(t->dest, SHUT_WR);
 936                 else
 937                         close(t->dest);
 938                 transfer_debug("Closed %s.", t->dest_name);
 939         }
 940 }
 941
 942 /*
 943  * Tries to read read data from source into buffer. If buffer is full,
 944  * no data is read. Returns 0 on success, -1 on error.
 945  */
 946 static int udt_do_read(struct unidirectional_transfer *t)
 947 {
 948         ssize_t bytes;
 949
 950         if (t->bufuse == BUFFERSIZE)
 951                 return 0;       /* No space for more. */
 952
 953         transfer_debug("%s is readable", t->src_name);
 954         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 955         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 956                 errno != EINTR) {
 957                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 958                 return -1;
 959         } else if (bytes == 0) {
 960                 transfer_debug("%s EOF (with %i bytes in buffer)",
 961                         t->src_name, t->bufuse);
 962                 t->state = SSTATE_FLUSHING;
 963         } else if (bytes > 0) {
 964                 t->bufuse += bytes;
 965                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 966                         (int)bytes, t->src_name, (int)t->bufuse);
 967         }
 968         return 0;
 969 }
 970
 971 /* Tries to write data from buffer into destination. If buffer is empty,
 972  * no data is written. Returns 0 on success, -1 on error.
 973  */
 974 static int udt_do_write(struct unidirectional_transfer *t)
 975 {
 976         size_t bytes;
 977
 978         if (t->bufuse == 0)
 979                 return 0;       /* Nothing to write. */
 980
 981         transfer_debug("%s is writable", t->dest_name);
 982         bytes = write(t->dest, t->buf, t->bufuse);
 983         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 984                 errno != EINTR) {
 985                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
 986                 return -1;
 987         } else if (bytes > 0) {
 988                 t->bufuse -= bytes;
 989                 if (t->bufuse)
 990                         memmove(t->buf, t->buf + bytes, t->bufuse);
 991                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
 992                         (int)bytes, t->dest_name, (int)t->bufuse);
 993         }
 994         return 0;
 995 }
 996
 997
 998 /* State of bidirectional transfer loop. */
 999 struct bidirectional_transfer_state {
1000         /* Direction from program to git. */
1001         struct unidirectional_transfer ptg;
1002         /* Direction from git to program. */
1003         struct unidirectional_transfer gtp;
1004 };
1005
1006 static void *udt_copy_task_routine(void *udt)
1007 {
1008         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1009         while (t->state != SSTATE_FINISHED) {
1010                 if (STATE_NEEDS_READING(t->state))
1011                         if (udt_do_read(t))
1012                                 return NULL;
1013                 if (STATE_NEEDS_WRITING(t->state))
1014                         if (udt_do_write(t))
1015                                 return NULL;
1016                 if (STATE_NEEDS_CLOSING(t->state))
1017                         udt_close_if_finished(t);
1018         }
1019         return udt;     /* Just some non-NULL value. */
1020 }
1021
1022 #ifndef NO_PTHREADS
1023
1024 /*
1025  * Join thread, with apporiate errors on failure. Name is name for the
1026  * thread (for error messages). Returns 0 on success, 1 on failure.
1027  */
1028 static int tloop_join(pthread_t thread, const char *name)
1029 {
1030         int err;
1031         void *tret;
1032         err = pthread_join(thread, &tret);
1033         if (!tret) {
1034                 error("%s thread failed", name);
1035                 return 1;
1036         }
1037         if (err) {
1038                 error("%s thread failed to join: %s", name, strerror(err));
1039                 return 1;
1040         }
1041         return 0;
1042 }
1043
1044 /*
1045  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1046  * -1 on failure.
1047  */
1048 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1049 {
1050         pthread_t gtp_thread;
1051         pthread_t ptg_thread;
1052         int err;
1053         int ret = 0;
1054         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1055                 &s->gtp);
1056         if (err)
1057                 die("Can't start thread for copying data: %s", strerror(err));
1058         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1059                 &s->ptg);
1060         if (err)
1061                 die("Can't start thread for copying data: %s", strerror(err));
1062
1063         ret |= tloop_join(gtp_thread, "Git to program copy");
1064         ret |= tloop_join(ptg_thread, "Program to git copy");
1065         return ret;
1066 }
1067 #else
1068
1069 /* Close the source and target (for writing) for transfer. */
1070 static void udt_kill_transfer(struct unidirectional_transfer *t)
1071 {
1072         t->state = SSTATE_FINISHED;
1073         /*
1074          * Socket read end left open isn't a disaster if nobody
1075          * attempts to read from it (mingw compat headers do not
1076          * have SHUT_RD)...
1077          *
1078          * We can't fully close the socket since otherwise gtp
1079          * task would first close the socket it sends data to
1080          * while closing the ptg file descriptors.
1081          */
1082         if (!t->src_is_sock)
1083                 close(t->src);
1084         if (t->dest_is_sock)
1085                 shutdown(t->dest, SHUT_WR);
1086         else
1087                 close(t->dest);
1088 }
1089
1090 /*
1091  * Join process, with apporiate errors on failure. Name is name for the
1092  * process (for error messages). Returns 0 on success, 1 on failure.
1093  */
1094 static int tloop_join(pid_t pid, const char *name)
1095 {
1096         int tret;
1097         if (waitpid(pid, &tret, 0) < 0) {
1098                 error("%s process failed to wait: %s", name, strerror(errno));
1099                 return 1;
1100         }
1101         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1102                 error("%s process failed", name);
1103                 return 1;
1104         }
1105         return 0;
1106 }
1107
1108 /*
1109  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1110  * -1 on failure.
1111  */
1112 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1113 {
1114         pid_t pid1, pid2;
1115         int ret = 0;
1116
1117         /* Fork thread #1: git to program. */
1118         pid1 = fork();
1119         if (pid1 < 0)
1120                 die_errno("Can't start thread for copying data");
1121         else if (pid1 == 0) {
1122                 udt_kill_transfer(&s->ptg);
1123                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1124         }
1125
1126         /* Fork thread #2: program to git. */
1127         pid2 = fork();
1128         if (pid2 < 0)
1129                 die_errno("Can't start thread for copying data");
1130         else if (pid2 == 0) {
1131                 udt_kill_transfer(&s->gtp);
1132                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1133         }
1134
1135         /*
1136          * Close both streams in parent as to not interfere with
1137          * end of file detection and wait for both tasks to finish.
1138          */
1139         udt_kill_transfer(&s->gtp);
1140         udt_kill_transfer(&s->ptg);
1141         ret |= tloop_join(pid1, "Git to program copy");
1142         ret |= tloop_join(pid2, "Program to git copy");
1143         return ret;
1144 }
1145 #endif
1146
1147 /*
1148  * Copies data from stdin to output and from input to stdout simultaneously.
1149  * Additionally filtering through given filter. If filter is NULL, uses
1150  * identity filter.
1151  */
1152 int bidirectional_transfer_loop(int input, int output)
1153 {
1154         struct bidirectional_transfer_state state;
1155
1156         /* Fill the state fields. */
1157         state.ptg.src = input;
1158         state.ptg.dest = 1;
1159         state.ptg.src_is_sock = (input == output);
1160         state.ptg.dest_is_sock = 0;
1161         state.ptg.state = SSTATE_TRANSFERING;
1162         state.ptg.bufuse = 0;
1163         state.ptg.src_name = "remote input";
1164         state.ptg.dest_name = "stdout";
1165
1166         state.gtp.src = 0;
1167         state.gtp.dest = output;
1168         state.gtp.src_is_sock = 0;
1169         state.gtp.dest_is_sock = (input == output);
1170         state.gtp.state = SSTATE_TRANSFERING;
1171         state.gtp.bufuse = 0;
1172         state.gtp.src_name = "stdin";
1173         state.gtp.dest_name = "remote output";
1174
1175         return tloop_spawnwait_tasks(&state);
1176 }