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         char *export_marks;
  27         char *import_marks;
  28         /* These go from remote name (as in "list") to private name */
  29         struct refspec *refspecs;
  30         int refspec_nr;
  31         /* Transport options for fetch-pack/send-pack (should one of
  32          * those be invoked).
  33          */
  34         struct git_transport_options transport_options;
  35 };
  36
  37 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  38 {
  39         if (debug)
  40                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  41         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  42                 != buffer->len)
  43                 die_errno("Full write to remote helper failed");
  44 }
  45
  46 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  47 {
  48         strbuf_reset(buffer);
  49         if (debug)
  50                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  51         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  52                 if (debug)
  53                         fprintf(stderr, "Debug: Remote helper quit.\n");
  54                 exit(128);
  55         }
  56
  57         if (debug)
  58                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  59         return 0;
  60 }
  61
  62 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  63 {
  64         return recvline_fh(helper->out, buffer);
  65 }
  66
  67 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  68 {
  69         sendline(helper, buffer);
  70         recvline(helper, buffer);
  71 }
  72
  73 static void write_constant(int fd, const char *str)
  74 {
  75         if (debug)
  76                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  77         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  78                 die_errno("Full write to remote helper failed");
  79 }
  80
  81 static const char *remove_ext_force(const char *url)
  82 {
  83         if (url) {
  84                 const char *colon = strchr(url, ':');
  85                 if (colon && colon[1] == ':')
  86                         return colon + 2;
  87         }
  88         return url;
  89 }
  90
  91 static void do_take_over(struct transport *transport)
  92 {
  93         struct helper_data *data;
  94         data = (struct helper_data *)transport->data;
  95         transport_take_over(transport, data->helper);
  96         fclose(data->out);
  97         free(data);
  98 }
  99
 100 static struct child_process *get_helper(struct transport *transport)
 101 {
 102         struct helper_data *data = transport->data;
 103         struct strbuf buf = STRBUF_INIT;
 104         struct child_process *helper;
 105         const char **refspecs = NULL;
 106         int refspec_nr = 0;
 107         int refspec_alloc = 0;
 108         int duped;
 109         int code;
 110         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 111         const char *helper_env[] = {
 112                 git_dir_buf,
 113                 NULL
 114         };
 115
 116
 117         if (data->helper)
 118                 return data->helper;
 119
 120         helper = xcalloc(1, sizeof(*helper));
 121         helper->in = -1;
 122         helper->out = -1;
 123         helper->err = 0;
 124         helper->argv = xcalloc(4, sizeof(*helper->argv));
 125         strbuf_addf(&buf, "git-remote-%s", data->name);
 126         helper->argv[0] = strbuf_detach(&buf, NULL);
 127         helper->argv[1] = transport->remote->name;
 128         helper->argv[2] = remove_ext_force(transport->url);
 129         helper->git_cmd = 0;
 130         helper->silent_exec_failure = 1;
 131
 132         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 133         helper->env = helper_env;
 134
 135         code = start_command(helper);
 136         if (code < 0 && errno == ENOENT)
 137                 die("Unable to find remote helper for '%s'", data->name);
 138         else if (code != 0)
 139                 exit(code);
 140
 141         data->helper = helper;
 142         data->no_disconnect_req = 0;
 143
 144         /*
 145          * Open the output as FILE* so strbuf_getline() can be used.
 146          * Do this with duped fd because fclose() will close the fd,
 147          * and stuff like taking over will require the fd to remain.
 148          */
 149         duped = dup(helper->out);
 150         if (duped < 0)
 151                 die_errno("Can't dup helper output fd");
 152         data->out = xfdopen(duped, "r");
 153
 154         write_constant(helper->in, "capabilities\n");
 155
 156         while (1) {
 157                 const char *capname;
 158                 int mandatory = 0;
 159                 recvline(data, &buf);
 160
 161                 if (!*buf.buf)
 162                         break;
 163
 164                 if (*buf.buf == '*') {
 165                         capname = buf.buf + 1;
 166                         mandatory = 1;
 167                 } else
 168                         capname = buf.buf;
 169
 170                 if (debug)
 171                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 172                 if (!strcmp(capname, "fetch"))
 173                         data->fetch = 1;
 174                 else if (!strcmp(capname, "option"))
 175                         data->option = 1;
 176                 else if (!strcmp(capname, "push"))
 177                         data->push = 1;
 178                 else if (!strcmp(capname, "import"))
 179                         data->import = 1;
 180                 else if (!strcmp(capname, "export"))
 181                         data->export = 1;
 182                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 183                         ALLOC_GROW(refspecs,
 184                                    refspec_nr + 1,
 185                                    refspec_alloc);
 186                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 187                 } else if (!strcmp(capname, "connect")) {
 188                         data->connect = 1;
 189                 } else if (!prefixcmp(capname, "export-marks ")) {
 190                         struct strbuf arg = STRBUF_INIT;
 191                         strbuf_addstr(&arg, "--export-marks=");
 192                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 193                         data->export_marks = strbuf_detach(&arg, NULL);
 194                 } else if (!prefixcmp(capname, "import-marks")) {
 195                         struct strbuf arg = STRBUF_INIT;
 196                         strbuf_addstr(&arg, "--import-marks=");
 197                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 198                         data->import_marks = strbuf_detach(&arg, NULL);
 199                 } else if (mandatory) {
 200                         die("Unknown mandatory capability %s. This remote "
 201                             "helper probably needs newer version of Git.\n",
 202                             capname);
 203                 }
 204         }
 205         if (refspecs) {
 206                 int i;
 207                 data->refspec_nr = refspec_nr;
 208                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 209                 for (i = 0; i < refspec_nr; i++) {
 210                         free((char *)refspecs[i]);
 211                 }
 212                 free(refspecs);
 213         }
 214         strbuf_release(&buf);
 215         if (debug)
 216                 fprintf(stderr, "Debug: Capabilities complete.\n");
 217         return data->helper;
 218 }
 219
 220 static int disconnect_helper(struct transport *transport)
 221 {
 222         struct helper_data *data = transport->data;
 223         struct strbuf buf = STRBUF_INIT;
 224         int res = 0;
 225
 226         if (data->helper) {
 227                 if (debug)
 228                         fprintf(stderr, "Debug: Disconnecting.\n");
 229                 if (!data->no_disconnect_req) {
 230                         strbuf_addf(&buf, "\n");
 231                         sendline(data, &buf);
 232                 }
 233                 close(data->helper->in);
 234                 close(data->helper->out);
 235                 fclose(data->out);
 236                 res = finish_command(data->helper);
 237                 free((char *)data->helper->argv[0]);
 238                 free(data->helper->argv);
 239                 free(data->helper);
 240                 data->helper = NULL;
 241         }
 242         return res;
 243 }
 244
 245 static const char *unsupported_options[] = {
 246         TRANS_OPT_UPLOADPACK,
 247         TRANS_OPT_RECEIVEPACK,
 248         TRANS_OPT_THIN,
 249         TRANS_OPT_KEEP
 250         };
 251 static const char *boolean_options[] = {
 252         TRANS_OPT_THIN,
 253         TRANS_OPT_KEEP,
 254         TRANS_OPT_FOLLOWTAGS
 255         };
 256
 257 static int set_helper_option(struct transport *transport,
 258                           const char *name, const char *value)
 259 {
 260         struct helper_data *data = transport->data;
 261         struct strbuf buf = STRBUF_INIT;
 262         int i, ret, is_bool = 0;
 263
 264         get_helper(transport);
 265
 266         if (!data->option)
 267                 return 1;
 268
 269         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 270                 if (!strcmp(name, unsupported_options[i]))
 271                         return 1;
 272         }
 273
 274         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 275                 if (!strcmp(name, boolean_options[i])) {
 276                         is_bool = 1;
 277                         break;
 278                 }
 279         }
 280
 281         strbuf_addf(&buf, "option %s ", name);
 282         if (is_bool)
 283                 strbuf_addstr(&buf, value ? "true" : "false");
 284         else
 285                 quote_c_style(value, &buf, NULL, 0);
 286         strbuf_addch(&buf, '\n');
 287
 288         xchgline(data, &buf);
 289
 290         if (!strcmp(buf.buf, "ok"))
 291                 ret = 0;
 292         else if (!prefixcmp(buf.buf, "error")) {
 293                 ret = -1;
 294         } else if (!strcmp(buf.buf, "unsupported"))
 295                 ret = 1;
 296         else {
 297                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 298                 ret = 1;
 299         }
 300         strbuf_release(&buf);
 301         return ret;
 302 }
 303
 304 static void standard_options(struct transport *t)
 305 {
 306         char buf[16];
 307         int n;
 308         int v = t->verbose;
 309
 310         set_helper_option(t, "progress", t->progress ? "true" : "false");
 311
 312         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 313         if (n >= sizeof(buf))
 314                 die("impossibly large verbosity value");
 315         set_helper_option(t, "verbosity", buf);
 316 }
 317
 318 static int release_helper(struct transport *transport)
 319 {
 320         int res = 0;
 321         struct helper_data *data = transport->data;
 322         free_refspec(data->refspec_nr, data->refspecs);
 323         data->refspecs = NULL;
 324         res = disconnect_helper(transport);
 325         free(transport->data);
 326         return res;
 327 }
 328
 329 static int fetch_with_fetch(struct transport *transport,
 330                             int nr_heads, struct ref **to_fetch)
 331 {
 332         struct helper_data *data = transport->data;
 333         int i;
 334         struct strbuf buf = STRBUF_INIT;
 335
 336         standard_options(transport);
 337
 338         for (i = 0; i < nr_heads; i++) {
 339                 const struct ref *posn = to_fetch[i];
 340                 if (posn->status & REF_STATUS_UPTODATE)
 341                         continue;
 342
 343                 strbuf_addf(&buf, "fetch %s %s\n",
 344                             sha1_to_hex(posn->old_sha1), posn->name);
 345         }
 346
 347         strbuf_addch(&buf, '\n');
 348         sendline(data, &buf);
 349
 350         while (1) {
 351                 recvline(data, &buf);
 352
 353                 if (!prefixcmp(buf.buf, "lock ")) {
 354                         const char *name = buf.buf + 5;
 355                         if (transport->pack_lockfile)
 356                                 warning("%s also locked %s", data->name, name);
 357                         else
 358                                 transport->pack_lockfile = xstrdup(name);
 359                 }
 360                 else if (!buf.len)
 361                         break;
 362                 else
 363                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 364         }
 365         strbuf_release(&buf);
 366         return 0;
 367 }
 368
 369 static int get_importer(struct transport *transport, struct child_process *fastimport)
 370 {
 371         struct child_process *helper = get_helper(transport);
 372         memset(fastimport, 0, sizeof(*fastimport));
 373         fastimport->in = helper->out;
 374         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 375         fastimport->argv[0] = "fast-import";
 376         fastimport->argv[1] = "--quiet";
 377
 378         fastimport->git_cmd = 1;
 379         return start_command(fastimport);
 380 }
 381
 382 static int get_exporter(struct transport *transport,
 383                         struct child_process *fastexport,
 384                         struct string_list *revlist_args)
 385 {
 386         struct helper_data *data = transport->data;
 387         struct child_process *helper = get_helper(transport);
 388         int argc = 0, i;
 389         memset(fastexport, 0, sizeof(*fastexport));
 390
 391         /* we need to duplicate helper->in because we want to use it after
 392          * fastexport is done with it. */
 393         fastexport->out = dup(helper->in);
 394         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
 395         fastexport->argv[argc++] = "fast-export";
 396         fastexport->argv[argc++] = "--use-done-feature";
 397         if (data->export_marks)
 398                 fastexport->argv[argc++] = data->export_marks;
 399         if (data->import_marks)
 400                 fastexport->argv[argc++] = data->import_marks;
 401
 402         for (i = 0; i < revlist_args->nr; i++)
 403                 fastexport->argv[argc++] = revlist_args->items[i].string;
 404
 405         fastexport->git_cmd = 1;
 406         return start_command(fastexport);
 407 }
 408
 409 static int fetch_with_import(struct transport *transport,
 410                              int nr_heads, struct ref **to_fetch)
 411 {
 412         struct child_process fastimport;
 413         struct helper_data *data = transport->data;
 414         int i;
 415         struct ref *posn;
 416         struct strbuf buf = STRBUF_INIT;
 417
 418         get_helper(transport);
 419
 420         if (get_importer(transport, &fastimport))
 421                 die("Couldn't run fast-import");
 422
 423         for (i = 0; i < nr_heads; i++) {
 424                 posn = to_fetch[i];
 425                 if (posn->status & REF_STATUS_UPTODATE)
 426                         continue;
 427
 428                 strbuf_addf(&buf, "import %s\n", posn->name);
 429                 sendline(data, &buf);
 430                 strbuf_reset(&buf);
 431         }
 432
 433         write_constant(data->helper->in, "\n");
 434
 435         if (finish_command(&fastimport))
 436                 die("Error while running fast-import");
 437         free(fastimport.argv);
 438         fastimport.argv = NULL;
 439
 440         for (i = 0; i < nr_heads; i++) {
 441                 char *private;
 442                 posn = to_fetch[i];
 443                 if (posn->status & REF_STATUS_UPTODATE)
 444                         continue;
 445                 if (data->refspecs)
 446                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 447                 else
 448                         private = xstrdup(posn->name);
 449                 if (private) {
 450                         read_ref(private, posn->old_sha1);
 451                         free(private);
 452                 }
 453         }
 454         strbuf_release(&buf);
 455         return 0;
 456 }
 457
 458 static int process_connect_service(struct transport *transport,
 459                                    const char *name, const char *exec)
 460 {
 461         struct helper_data *data = transport->data;
 462         struct strbuf cmdbuf = STRBUF_INIT;
 463         struct child_process *helper;
 464         int r, duped, ret = 0;
 465         FILE *input;
 466
 467         helper = get_helper(transport);
 468
 469         /*
 470          * Yes, dup the pipe another time, as we need unbuffered version
 471          * of input pipe as FILE*. fclose() closes the underlying fd and
 472          * stream buffering only can be changed before first I/O operation
 473          * on it.
 474          */
 475         duped = dup(helper->out);
 476         if (duped < 0)
 477                 die_errno("Can't dup helper output fd");
 478         input = xfdopen(duped, "r");
 479         setvbuf(input, NULL, _IONBF, 0);
 480
 481         /*
 482          * Handle --upload-pack and friends. This is fire and forget...
 483          * just warn if it fails.
 484          */
 485         if (strcmp(name, exec)) {
 486                 r = set_helper_option(transport, "servpath", exec);
 487                 if (r > 0)
 488                         warning("Setting remote service path not supported by protocol.");
 489                 else if (r < 0)
 490                         warning("Invalid remote service path.");
 491         }
 492
 493         if (data->connect)
 494                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 495         else
 496                 goto exit;
 497
 498         sendline(data, &cmdbuf);
 499         recvline_fh(input, &cmdbuf);
 500         if (!strcmp(cmdbuf.buf, "")) {
 501                 data->no_disconnect_req = 1;
 502                 if (debug)
 503                         fprintf(stderr, "Debug: Smart transport connection "
 504                                 "ready.\n");
 505                 ret = 1;
 506         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 507                 if (debug)
 508                         fprintf(stderr, "Debug: Falling back to dumb "
 509                                 "transport.\n");
 510         } else
 511                 die("Unknown response to connect: %s",
 512                         cmdbuf.buf);
 513
 514 exit:
 515         fclose(input);
 516         return ret;
 517 }
 518
 519 static int process_connect(struct transport *transport,
 520                                      int for_push)
 521 {
 522         struct helper_data *data = transport->data;
 523         const char *name;
 524         const char *exec;
 525
 526         name = for_push ? "git-receive-pack" : "git-upload-pack";
 527         if (for_push)
 528                 exec = data->transport_options.receivepack;
 529         else
 530                 exec = data->transport_options.uploadpack;
 531
 532         return process_connect_service(transport, name, exec);
 533 }
 534
 535 static int connect_helper(struct transport *transport, const char *name,
 536                    const char *exec, int fd[2])
 537 {
 538         struct helper_data *data = transport->data;
 539
 540         /* Get_helper so connect is inited. */
 541         get_helper(transport);
 542         if (!data->connect)
 543                 die("Operation not supported by protocol.");
 544
 545         if (!process_connect_service(transport, name, exec))
 546                 die("Can't connect to subservice %s.", name);
 547
 548         fd[0] = data->helper->out;
 549         fd[1] = data->helper->in;
 550         return 0;
 551 }
 552
 553 static int fetch(struct transport *transport,
 554                  int nr_heads, struct ref **to_fetch)
 555 {
 556         struct helper_data *data = transport->data;
 557         int i, count;
 558
 559         if (process_connect(transport, 0)) {
 560                 do_take_over(transport);
 561                 return transport->fetch(transport, nr_heads, to_fetch);
 562         }
 563
 564         count = 0;
 565         for (i = 0; i < nr_heads; i++)
 566                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 567                         count++;
 568
 569         if (!count)
 570                 return 0;
 571
 572         if (data->fetch)
 573                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 574
 575         if (data->import)
 576                 return fetch_with_import(transport, nr_heads, to_fetch);
 577
 578         return -1;
 579 }
 580
 581 static void push_update_ref_status(struct strbuf *buf,
 582                                    struct ref **ref,
 583                                    struct ref *remote_refs)
 584 {
 585         char *refname, *msg;
 586         int status;
 587
 588         if (!prefixcmp(buf->buf, "ok ")) {
 589                 status = REF_STATUS_OK;
 590                 refname = buf->buf + 3;
 591         } else if (!prefixcmp(buf->buf, "error ")) {
 592                 status = REF_STATUS_REMOTE_REJECT;
 593                 refname = buf->buf + 6;
 594         } else
 595                 die("expected ok/error, helper said '%s'\n", buf->buf);
 596
 597         msg = strchr(refname, ' ');
 598         if (msg) {
 599                 struct strbuf msg_buf = STRBUF_INIT;
 600                 const char *end;
 601
 602                 *msg++ = '\0';
 603                 if (!unquote_c_style(&msg_buf, msg, &end))
 604                         msg = strbuf_detach(&msg_buf, NULL);
 605                 else
 606                         msg = xstrdup(msg);
 607                 strbuf_release(&msg_buf);
 608
 609                 if (!strcmp(msg, "no match")) {
 610                         status = REF_STATUS_NONE;
 611                         free(msg);
 612                         msg = NULL;
 613                 }
 614                 else if (!strcmp(msg, "up to date")) {
 615                         status = REF_STATUS_UPTODATE;
 616                         free(msg);
 617                         msg = NULL;
 618                 }
 619                 else if (!strcmp(msg, "non-fast forward")) {
 620                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 621                         free(msg);
 622                         msg = NULL;
 623                 }
 624         }
 625
 626         if (*ref)
 627                 *ref = find_ref_by_name(*ref, refname);
 628         if (!*ref)
 629                 *ref = find_ref_by_name(remote_refs, refname);
 630         if (!*ref) {
 631                 warning("helper reported unexpected status of %s", refname);
 632                 return;
 633         }
 634
 635         if ((*ref)->status != REF_STATUS_NONE) {
 636                 /*
 637                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 638                  * status reported by the remote helper if the latter is 'no match'.
 639                  */
 640                 if (status == REF_STATUS_NONE)
 641                         return;
 642         }
 643
 644         (*ref)->status = status;
 645         (*ref)->remote_status = msg;
 646 }
 647
 648 static void push_update_refs_status(struct helper_data *data,
 649                                     struct ref *remote_refs)
 650 {
 651         struct strbuf buf = STRBUF_INIT;
 652         struct ref *ref = remote_refs;
 653         for (;;) {
 654                 recvline(data, &buf);
 655                 if (!buf.len)
 656                         break;
 657
 658                 push_update_ref_status(&buf, &ref, remote_refs);
 659         }
 660         strbuf_release(&buf);
 661 }
 662
 663 static int push_refs_with_push(struct transport *transport,
 664                 struct ref *remote_refs, int flags)
 665 {
 666         int force_all = flags & TRANSPORT_PUSH_FORCE;
 667         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 668         struct helper_data *data = transport->data;
 669         struct strbuf buf = STRBUF_INIT;
 670         struct ref *ref;
 671
 672         get_helper(transport);
 673         if (!data->push)
 674                 return 1;
 675
 676         for (ref = remote_refs; ref; ref = ref->next) {
 677                 if (!ref->peer_ref && !mirror)
 678                         continue;
 679
 680                 /* Check for statuses set by set_ref_status_for_push() */
 681                 switch (ref->status) {
 682                 case REF_STATUS_REJECT_NONFASTFORWARD:
 683                 case REF_STATUS_UPTODATE:
 684                         continue;
 685                 default:
 686                         ; /* do nothing */
 687                 }
 688
 689                 if (force_all)
 690                         ref->force = 1;
 691
 692                 strbuf_addstr(&buf, "push ");
 693                 if (!ref->deletion) {
 694                         if (ref->force)
 695                                 strbuf_addch(&buf, '+');
 696                         if (ref->peer_ref)
 697                                 strbuf_addstr(&buf, ref->peer_ref->name);
 698                         else
 699                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 700                 }
 701                 strbuf_addch(&buf, ':');
 702                 strbuf_addstr(&buf, ref->name);
 703                 strbuf_addch(&buf, '\n');
 704         }
 705         if (buf.len == 0)
 706                 return 0;
 707
 708         standard_options(transport);
 709
 710         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 711                 if (set_helper_option(transport, "dry-run", "true") != 0)
 712                         die("helper %s does not support dry-run", data->name);
 713         }
 714
 715         strbuf_addch(&buf, '\n');
 716         sendline(data, &buf);
 717         strbuf_release(&buf);
 718
 719         push_update_refs_status(data, remote_refs);
 720         return 0;
 721 }
 722
 723 static int push_refs_with_export(struct transport *transport,
 724                 struct ref *remote_refs, int flags)
 725 {
 726         struct ref *ref;
 727         struct child_process *helper, exporter;
 728         struct helper_data *data = transport->data;
 729         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 730         struct strbuf buf = STRBUF_INIT;
 731
 732         helper = get_helper(transport);
 733
 734         write_constant(helper->in, "export\n");
 735
 736         strbuf_reset(&buf);
 737
 738         for (ref = remote_refs; ref; ref = ref->next) {
 739                 char *private;
 740                 unsigned char sha1[20];
 741
 742                 if (!data->refspecs)
 743                         continue;
 744                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 745                 if (private && !get_sha1(private, sha1)) {
 746                         strbuf_addf(&buf, "^%s", private);
 747                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 748                 }
 749                 free(private);
 750
 751                 if (ref->deletion) {
 752                         die("remote-helpers do not support ref deletion");
 753                 }
 754
 755                 if (ref->peer_ref)
 756                         string_list_append(&revlist_args, ref->peer_ref->name);
 757
 758         }
 759
 760         if (get_exporter(transport, &exporter, &revlist_args))
 761                 die("Couldn't run fast-export");
 762
 763         if (finish_command(&exporter))
 764                 die("Error while running fast-export");
 765         push_update_refs_status(data, remote_refs);
 766         return 0;
 767 }
 768
 769 static int push_refs(struct transport *transport,
 770                 struct ref *remote_refs, int flags)
 771 {
 772         struct helper_data *data = transport->data;
 773
 774         if (process_connect(transport, 1)) {
 775                 do_take_over(transport);
 776                 return transport->push_refs(transport, remote_refs, flags);
 777         }
 778
 779         if (!remote_refs) {
 780                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 781                         "Perhaps you should specify a branch such as 'master'.\n");
 782                 return 0;
 783         }
 784
 785         if (data->push)
 786                 return push_refs_with_push(transport, remote_refs, flags);
 787
 788         if (data->export)
 789                 return push_refs_with_export(transport, remote_refs, flags);
 790
 791         return -1;
 792 }
 793
 794
 795 static int has_attribute(const char *attrs, const char *attr) {
 796         int len;
 797         if (!attrs)
 798                 return 0;
 799
 800         len = strlen(attr);
 801         for (;;) {
 802                 const char *space = strchrnul(attrs, ' ');
 803                 if (len == space - attrs && !strncmp(attrs, attr, len))
 804                         return 1;
 805                 if (!*space)
 806                         return 0;
 807                 attrs = space + 1;
 808         }
 809 }
 810
 811 static struct ref *get_refs_list(struct transport *transport, int for_push)
 812 {
 813         struct helper_data *data = transport->data;
 814         struct child_process *helper;
 815         struct ref *ret = NULL;
 816         struct ref **tail = &ret;
 817         struct ref *posn;
 818         struct strbuf buf = STRBUF_INIT;
 819
 820         helper = get_helper(transport);
 821
 822         if (process_connect(transport, for_push)) {
 823                 do_take_over(transport);
 824                 return transport->get_refs_list(transport, for_push);
 825         }
 826
 827         if (data->push && for_push)
 828                 write_str_in_full(helper->in, "list for-push\n");
 829         else
 830                 write_str_in_full(helper->in, "list\n");
 831
 832         while (1) {
 833                 char *eov, *eon;
 834                 recvline(data, &buf);
 835
 836                 if (!*buf.buf)
 837                         break;
 838
 839                 eov = strchr(buf.buf, ' ');
 840                 if (!eov)
 841                         die("Malformed response in ref list: %s", buf.buf);
 842                 eon = strchr(eov + 1, ' ');
 843                 *eov = '\0';
 844                 if (eon)
 845                         *eon = '\0';
 846                 *tail = alloc_ref(eov + 1);
 847                 if (buf.buf[0] == '@')
 848                         (*tail)->symref = xstrdup(buf.buf + 1);
 849                 else if (buf.buf[0] != '?')
 850                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 851                 if (eon) {
 852                         if (has_attribute(eon + 1, "unchanged")) {
 853                                 (*tail)->status |= REF_STATUS_UPTODATE;
 854                                 read_ref((*tail)->name, (*tail)->old_sha1);
 855                         }
 856                 }
 857                 tail = &((*tail)->next);
 858         }
 859         if (debug)
 860                 fprintf(stderr, "Debug: Read ref listing.\n");
 861         strbuf_release(&buf);
 862
 863         for (posn = ret; posn; posn = posn->next)
 864                 resolve_remote_symref(posn, ret);
 865
 866         return ret;
 867 }
 868
 869 int transport_helper_init(struct transport *transport, const char *name)
 870 {
 871         struct helper_data *data = xcalloc(sizeof(*data), 1);
 872         data->name = name;
 873
 874         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 875                 debug = 1;
 876
 877         transport->data = data;
 878         transport->set_option = set_helper_option;
 879         transport->get_refs_list = get_refs_list;
 880         transport->fetch = fetch;
 881         transport->push_refs = push_refs;
 882         transport->disconnect = release_helper;
 883         transport->connect = connect_helper;
 884         transport->smart_options = &(data->transport_options);
 885         return 0;
 886 }
 887
 888 /*
 889  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 890  * buffer less), so attempt reads and writes with up to that size.
 891  */
 892 #define BUFFERSIZE 65536
 893 /* This should be enough to hold debugging message. */
 894 #define PBUFFERSIZE 8192
 895
 896 /* Print bidirectional transfer loop debug message. */
 897 static void transfer_debug(const char *fmt, ...)
 898 {
 899         va_list args;
 900         char msgbuf[PBUFFERSIZE];
 901         static int debug_enabled = -1;
 902
 903         if (debug_enabled < 0)
 904                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 905         if (!debug_enabled)
 906                 return;
 907
 908         va_start(args, fmt);
 909         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 910         va_end(args);
 911         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 912 }
 913
 914 /* Stream state: More data may be coming in this direction. */
 915 #define SSTATE_TRANSFERING 0
 916 /*
 917  * Stream state: No more data coming in this direction, flushing rest of
 918  * data.
 919  */
 920 #define SSTATE_FLUSHING 1
 921 /* Stream state: Transfer in this direction finished. */
 922 #define SSTATE_FINISHED 2
 923
 924 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 925 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 926 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 927
 928 /* Unidirectional transfer. */
 929 struct unidirectional_transfer {
 930         /* Source */
 931         int src;
 932         /* Destination */
 933         int dest;
 934         /* Is source socket? */
 935         int src_is_sock;
 936         /* Is destination socket? */
 937         int dest_is_sock;
 938         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 939         int state;
 940         /* Buffer. */
 941         char buf[BUFFERSIZE];
 942         /* Buffer used. */
 943         size_t bufuse;
 944         /* Name of source. */
 945         const char *src_name;
 946         /* Name of destination. */
 947         const char *dest_name;
 948 };
 949
 950 /* Closes the target (for writing) if transfer has finished. */
 951 static void udt_close_if_finished(struct unidirectional_transfer *t)
 952 {
 953         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 954                 t->state = SSTATE_FINISHED;
 955                 if (t->dest_is_sock)
 956                         shutdown(t->dest, SHUT_WR);
 957                 else
 958                         close(t->dest);
 959                 transfer_debug("Closed %s.", t->dest_name);
 960         }
 961 }
 962
 963 /*
 964  * Tries to read read data from source into buffer. If buffer is full,
 965  * no data is read. Returns 0 on success, -1 on error.
 966  */
 967 static int udt_do_read(struct unidirectional_transfer *t)
 968 {
 969         ssize_t bytes;
 970
 971         if (t->bufuse == BUFFERSIZE)
 972                 return 0;       /* No space for more. */
 973
 974         transfer_debug("%s is readable", t->src_name);
 975         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 976         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 977                 errno != EINTR) {
 978                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 979                 return -1;
 980         } else if (bytes == 0) {
 981                 transfer_debug("%s EOF (with %i bytes in buffer)",
 982                         t->src_name, t->bufuse);
 983                 t->state = SSTATE_FLUSHING;
 984         } else if (bytes > 0) {
 985                 t->bufuse += bytes;
 986                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 987                         (int)bytes, t->src_name, (int)t->bufuse);
 988         }
 989         return 0;
 990 }
 991
 992 /* Tries to write data from buffer into destination. If buffer is empty,
 993  * no data is written. Returns 0 on success, -1 on error.
 994  */
 995 static int udt_do_write(struct unidirectional_transfer *t)
 996 {
 997         ssize_t bytes;
 998
 999         if (t->bufuse == 0)
1000                 return 0;       /* Nothing to write. */
1001
1002         transfer_debug("%s is writable", t->dest_name);
1003         bytes = write(t->dest, t->buf, t->bufuse);
1004         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1005                 errno != EINTR) {
1006                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1007                 return -1;
1008         } else if (bytes > 0) {
1009                 t->bufuse -= bytes;
1010                 if (t->bufuse)
1011                         memmove(t->buf, t->buf + bytes, t->bufuse);
1012                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1013                         (int)bytes, t->dest_name, (int)t->bufuse);
1014         }
1015         return 0;
1016 }
1017
1018
1019 /* State of bidirectional transfer loop. */
1020 struct bidirectional_transfer_state {
1021         /* Direction from program to git. */
1022         struct unidirectional_transfer ptg;
1023         /* Direction from git to program. */
1024         struct unidirectional_transfer gtp;
1025 };
1026
1027 static void *udt_copy_task_routine(void *udt)
1028 {
1029         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1030         while (t->state != SSTATE_FINISHED) {
1031                 if (STATE_NEEDS_READING(t->state))
1032                         if (udt_do_read(t))
1033                                 return NULL;
1034                 if (STATE_NEEDS_WRITING(t->state))
1035                         if (udt_do_write(t))
1036                                 return NULL;
1037                 if (STATE_NEEDS_CLOSING(t->state))
1038                         udt_close_if_finished(t);
1039         }
1040         return udt;     /* Just some non-NULL value. */
1041 }
1042
1043 #ifndef NO_PTHREADS
1044
1045 /*
1046  * Join thread, with apporiate errors on failure. Name is name for the
1047  * thread (for error messages). Returns 0 on success, 1 on failure.
1048  */
1049 static int tloop_join(pthread_t thread, const char *name)
1050 {
1051         int err;
1052         void *tret;
1053         err = pthread_join(thread, &tret);
1054         if (!tret) {
1055                 error("%s thread failed", name);
1056                 return 1;
1057         }
1058         if (err) {
1059                 error("%s thread failed to join: %s", name, strerror(err));
1060                 return 1;
1061         }
1062         return 0;
1063 }
1064
1065 /*
1066  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1067  * -1 on failure.
1068  */
1069 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1070 {
1071         pthread_t gtp_thread;
1072         pthread_t ptg_thread;
1073         int err;
1074         int ret = 0;
1075         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1076                 &s->gtp);
1077         if (err)
1078                 die("Can't start thread for copying data: %s", strerror(err));
1079         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1080                 &s->ptg);
1081         if (err)
1082                 die("Can't start thread for copying data: %s", strerror(err));
1083
1084         ret |= tloop_join(gtp_thread, "Git to program copy");
1085         ret |= tloop_join(ptg_thread, "Program to git copy");
1086         return ret;
1087 }
1088 #else
1089
1090 /* Close the source and target (for writing) for transfer. */
1091 static void udt_kill_transfer(struct unidirectional_transfer *t)
1092 {
1093         t->state = SSTATE_FINISHED;
1094         /*
1095          * Socket read end left open isn't a disaster if nobody
1096          * attempts to read from it (mingw compat headers do not
1097          * have SHUT_RD)...
1098          *
1099          * We can't fully close the socket since otherwise gtp
1100          * task would first close the socket it sends data to
1101          * while closing the ptg file descriptors.
1102          */
1103         if (!t->src_is_sock)
1104                 close(t->src);
1105         if (t->dest_is_sock)
1106                 shutdown(t->dest, SHUT_WR);
1107         else
1108                 close(t->dest);
1109 }
1110
1111 /*
1112  * Join process, with apporiate errors on failure. Name is name for the
1113  * process (for error messages). Returns 0 on success, 1 on failure.
1114  */
1115 static int tloop_join(pid_t pid, const char *name)
1116 {
1117         int tret;
1118         if (waitpid(pid, &tret, 0) < 0) {
1119                 error("%s process failed to wait: %s", name, strerror(errno));
1120                 return 1;
1121         }
1122         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1123                 error("%s process failed", name);
1124                 return 1;
1125         }
1126         return 0;
1127 }
1128
1129 /*
1130  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1131  * -1 on failure.
1132  */
1133 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1134 {
1135         pid_t pid1, pid2;
1136         int ret = 0;
1137
1138         /* Fork thread #1: git to program. */
1139         pid1 = fork();
1140         if (pid1 < 0)
1141                 die_errno("Can't start thread for copying data");
1142         else if (pid1 == 0) {
1143                 udt_kill_transfer(&s->ptg);
1144                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1145         }
1146
1147         /* Fork thread #2: program to git. */
1148         pid2 = fork();
1149         if (pid2 < 0)
1150                 die_errno("Can't start thread for copying data");
1151         else if (pid2 == 0) {
1152                 udt_kill_transfer(&s->gtp);
1153                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1154         }
1155
1156         /*
1157          * Close both streams in parent as to not interfere with
1158          * end of file detection and wait for both tasks to finish.
1159          */
1160         udt_kill_transfer(&s->gtp);
1161         udt_kill_transfer(&s->ptg);
1162         ret |= tloop_join(pid1, "Git to program copy");
1163         ret |= tloop_join(pid2, "Program to git copy");
1164         return ret;
1165 }
1166 #endif
1167
1168 /*
1169  * Copies data from stdin to output and from input to stdout simultaneously.
1170  * Additionally filtering through given filter. If filter is NULL, uses
1171  * identity filter.
1172  */
1173 int bidirectional_transfer_loop(int input, int output)
1174 {
1175         struct bidirectional_transfer_state state;
1176
1177         /* Fill the state fields. */
1178         state.ptg.src = input;
1179         state.ptg.dest = 1;
1180         state.ptg.src_is_sock = (input == output);
1181         state.ptg.dest_is_sock = 0;
1182         state.ptg.state = SSTATE_TRANSFERING;
1183         state.ptg.bufuse = 0;
1184         state.ptg.src_name = "remote input";
1185         state.ptg.dest_name = "stdout";
1186
1187         state.gtp.src = 0;
1188         state.gtp.dest = output;
1189         state.gtp.src_is_sock = 0;
1190         state.gtp.dest_is_sock = (input == output);
1191         state.gtp.state = SSTATE_TRANSFERING;
1192         state.gtp.bufuse = 0;
1193         state.gtp.src_name = "stdin";
1194         state.gtp.dest_name = "remote output";
1195
1196         return tloop_spawnwait_tasks(&state);
1197 }