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 #include "sigchain.h"
  13
  14 static int debug;
  15
  16 struct helper_data {
  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         char *export_marks;
  28         char *import_marks;
  29         /* These go from remote name (as in "list") to private name */
  30         struct refspec *refspecs;
  31         int refspec_nr;
  32         /* Transport options for fetch-pack/send-pack (should one of
  33          * those be invoked).
  34          */
  35         struct git_transport_options transport_options;
  36 };
  37
  38 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  39 {
  40         if (debug)
  41                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  42         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  43                 != buffer->len)
  44                 die_errno("Full write to remote helper failed");
  45 }
  46
  47 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  48 {
  49         strbuf_reset(buffer);
  50         if (debug)
  51                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  52         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  53                 if (debug)
  54                         fprintf(stderr, "Debug: Remote helper quit.\n");
  55                 exit(128);
  56         }
  57
  58         if (debug)
  59                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  60         return 0;
  61 }
  62
  63 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  64 {
  65         return recvline_fh(helper->out, buffer);
  66 }
  67
  68 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  69 {
  70         sendline(helper, buffer);
  71         recvline(helper, buffer);
  72 }
  73
  74 static void write_constant(int fd, const char *str)
  75 {
  76         if (debug)
  77                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  78         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  79                 die_errno("Full write to remote helper failed");
  80 }
  81
  82 static const char *remove_ext_force(const char *url)
  83 {
  84         if (url) {
  85                 const char *colon = strchr(url, ':');
  86                 if (colon && colon[1] == ':')
  87                         return colon + 2;
  88         }
  89         return url;
  90 }
  91
  92 static void do_take_over(struct transport *transport)
  93 {
  94         struct helper_data *data;
  95         data = (struct helper_data *)transport->data;
  96         transport_take_over(transport, data->helper);
  97         fclose(data->out);
  98         free(data);
  99 }
 100
 101 static struct child_process *get_helper(struct transport *transport)
 102 {
 103         struct helper_data *data = transport->data;
 104         struct strbuf buf = STRBUF_INIT;
 105         struct child_process *helper;
 106         const char **refspecs = NULL;
 107         int refspec_nr = 0;
 108         int refspec_alloc = 0;
 109         int duped;
 110         int code;
 111         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 112         const char *helper_env[] = {
 113                 git_dir_buf,
 114                 NULL
 115         };
 116
 117
 118         if (data->helper)
 119                 return data->helper;
 120
 121         helper = xcalloc(1, sizeof(*helper));
 122         helper->in = -1;
 123         helper->out = -1;
 124         helper->err = 0;
 125         helper->argv = xcalloc(4, sizeof(*helper->argv));
 126         strbuf_addf(&buf, "git-remote-%s", data->name);
 127         helper->argv[0] = strbuf_detach(&buf, NULL);
 128         helper->argv[1] = transport->remote->name;
 129         helper->argv[2] = remove_ext_force(transport->url);
 130         helper->git_cmd = 0;
 131         helper->silent_exec_failure = 1;
 132
 133         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 134         helper->env = helper_env;
 135
 136         code = start_command(helper);
 137         if (code < 0 && errno == ENOENT)
 138                 die("Unable to find remote helper for '%s'", data->name);
 139         else if (code != 0)
 140                 exit(code);
 141
 142         data->helper = helper;
 143         data->no_disconnect_req = 0;
 144
 145         /*
 146          * Open the output as FILE* so strbuf_getline() can be used.
 147          * Do this with duped fd because fclose() will close the fd,
 148          * and stuff like taking over will require the fd to remain.
 149          */
 150         duped = dup(helper->out);
 151         if (duped < 0)
 152                 die_errno("Can't dup helper output fd");
 153         data->out = xfdopen(duped, "r");
 154
 155         write_constant(helper->in, "capabilities\n");
 156
 157         while (1) {
 158                 const char *capname;
 159                 int mandatory = 0;
 160                 recvline(data, &buf);
 161
 162                 if (!*buf.buf)
 163                         break;
 164
 165                 if (*buf.buf == '*') {
 166                         capname = buf.buf + 1;
 167                         mandatory = 1;
 168                 } else
 169                         capname = buf.buf;
 170
 171                 if (debug)
 172                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 173                 if (!strcmp(capname, "fetch"))
 174                         data->fetch = 1;
 175                 else if (!strcmp(capname, "option"))
 176                         data->option = 1;
 177                 else if (!strcmp(capname, "push"))
 178                         data->push = 1;
 179                 else if (!strcmp(capname, "import"))
 180                         data->import = 1;
 181                 else if (!strcmp(capname, "export"))
 182                         data->export = 1;
 183                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 184                         ALLOC_GROW(refspecs,
 185                                    refspec_nr + 1,
 186                                    refspec_alloc);
 187                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 188                 } else if (!strcmp(capname, "connect")) {
 189                         data->connect = 1;
 190                 } else if (!prefixcmp(capname, "export-marks ")) {
 191                         struct strbuf arg = STRBUF_INIT;
 192                         strbuf_addstr(&arg, "--export-marks=");
 193                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 194                         data->export_marks = strbuf_detach(&arg, NULL);
 195                 } else if (!prefixcmp(capname, "import-marks")) {
 196                         struct strbuf arg = STRBUF_INIT;
 197                         strbuf_addstr(&arg, "--import-marks=");
 198                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 199                         data->import_marks = strbuf_detach(&arg, NULL);
 200                 } else if (mandatory) {
 201                         die("Unknown mandatory capability %s. This remote "
 202                             "helper probably needs newer version of Git.",
 203                             capname);
 204                 }
 205         }
 206         if (refspecs) {
 207                 int i;
 208                 data->refspec_nr = refspec_nr;
 209                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 210                 for (i = 0; i < refspec_nr; i++) {
 211                         free((char *)refspecs[i]);
 212                 }
 213                 free(refspecs);
 214         }
 215         strbuf_release(&buf);
 216         if (debug)
 217                 fprintf(stderr, "Debug: Capabilities complete.\n");
 218         return data->helper;
 219 }
 220
 221 static int disconnect_helper(struct transport *transport)
 222 {
 223         struct helper_data *data = transport->data;
 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                         /*
 231                          * Ignore write errors; there's nothing we can do,
 232                          * since we're about to close the pipe anyway. And the
 233                          * most likely error is EPIPE due to the helper dying
 234                          * to report an error itself.
 235                          */
 236                         sigchain_push(SIGPIPE, SIG_IGN);
 237                         xwrite(data->helper->in, "\n", 1);
 238                         sigchain_pop(SIGPIPE);
 239                 }
 240                 close(data->helper->in);
 241                 close(data->helper->out);
 242                 fclose(data->out);
 243                 res = finish_command(data->helper);
 244                 free((char *)data->helper->argv[0]);
 245                 free(data->helper->argv);
 246                 free(data->helper);
 247                 data->helper = NULL;
 248         }
 249         return res;
 250 }
 251
 252 static const char *unsupported_options[] = {
 253         TRANS_OPT_UPLOADPACK,
 254         TRANS_OPT_RECEIVEPACK,
 255         TRANS_OPT_THIN,
 256         TRANS_OPT_KEEP
 257         };
 258 static const char *boolean_options[] = {
 259         TRANS_OPT_THIN,
 260         TRANS_OPT_KEEP,
 261         TRANS_OPT_FOLLOWTAGS
 262         };
 263
 264 static int set_helper_option(struct transport *transport,
 265                           const char *name, const char *value)
 266 {
 267         struct helper_data *data = transport->data;
 268         struct strbuf buf = STRBUF_INIT;
 269         int i, ret, is_bool = 0;
 270
 271         get_helper(transport);
 272
 273         if (!data->option)
 274                 return 1;
 275
 276         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 277                 if (!strcmp(name, unsupported_options[i]))
 278                         return 1;
 279         }
 280
 281         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 282                 if (!strcmp(name, boolean_options[i])) {
 283                         is_bool = 1;
 284                         break;
 285                 }
 286         }
 287
 288         strbuf_addf(&buf, "option %s ", name);
 289         if (is_bool)
 290                 strbuf_addstr(&buf, value ? "true" : "false");
 291         else
 292                 quote_c_style(value, &buf, NULL, 0);
 293         strbuf_addch(&buf, '\n');
 294
 295         xchgline(data, &buf);
 296
 297         if (!strcmp(buf.buf, "ok"))
 298                 ret = 0;
 299         else if (!prefixcmp(buf.buf, "error")) {
 300                 ret = -1;
 301         } else if (!strcmp(buf.buf, "unsupported"))
 302                 ret = 1;
 303         else {
 304                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 305                 ret = 1;
 306         }
 307         strbuf_release(&buf);
 308         return ret;
 309 }
 310
 311 static void standard_options(struct transport *t)
 312 {
 313         char buf[16];
 314         int n;
 315         int v = t->verbose;
 316
 317         set_helper_option(t, "progress", t->progress ? "true" : "false");
 318
 319         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 320         if (n >= sizeof(buf))
 321                 die("impossibly large verbosity value");
 322         set_helper_option(t, "verbosity", buf);
 323 }
 324
 325 static int release_helper(struct transport *transport)
 326 {
 327         int res = 0;
 328         struct helper_data *data = transport->data;
 329         free_refspec(data->refspec_nr, data->refspecs);
 330         data->refspecs = NULL;
 331         res = disconnect_helper(transport);
 332         free(transport->data);
 333         return res;
 334 }
 335
 336 static int fetch_with_fetch(struct transport *transport,
 337                             int nr_heads, struct ref **to_fetch)
 338 {
 339         struct helper_data *data = transport->data;
 340         int i;
 341         struct strbuf buf = STRBUF_INIT;
 342
 343         standard_options(transport);
 344
 345         for (i = 0; i < nr_heads; i++) {
 346                 const struct ref *posn = to_fetch[i];
 347                 if (posn->status & REF_STATUS_UPTODATE)
 348                         continue;
 349
 350                 strbuf_addf(&buf, "fetch %s %s\n",
 351                             sha1_to_hex(posn->old_sha1), posn->name);
 352         }
 353
 354         strbuf_addch(&buf, '\n');
 355         sendline(data, &buf);
 356
 357         while (1) {
 358                 recvline(data, &buf);
 359
 360                 if (!prefixcmp(buf.buf, "lock ")) {
 361                         const char *name = buf.buf + 5;
 362                         if (transport->pack_lockfile)
 363                                 warning("%s also locked %s", data->name, name);
 364                         else
 365                                 transport->pack_lockfile = xstrdup(name);
 366                 }
 367                 else if (!buf.len)
 368                         break;
 369                 else
 370                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 371         }
 372         strbuf_release(&buf);
 373         return 0;
 374 }
 375
 376 static int get_importer(struct transport *transport, struct child_process *fastimport)
 377 {
 378         struct child_process *helper = get_helper(transport);
 379         memset(fastimport, 0, sizeof(*fastimport));
 380         fastimport->in = helper->out;
 381         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 382         fastimport->argv[0] = "fast-import";
 383         fastimport->argv[1] = "--quiet";
 384
 385         fastimport->git_cmd = 1;
 386         return start_command(fastimport);
 387 }
 388
 389 static int get_exporter(struct transport *transport,
 390                         struct child_process *fastexport,
 391                         struct string_list *revlist_args)
 392 {
 393         struct helper_data *data = transport->data;
 394         struct child_process *helper = get_helper(transport);
 395         int argc = 0, i;
 396         memset(fastexport, 0, sizeof(*fastexport));
 397
 398         /* we need to duplicate helper->in because we want to use it after
 399          * fastexport is done with it. */
 400         fastexport->out = dup(helper->in);
 401         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
 402         fastexport->argv[argc++] = "fast-export";
 403         fastexport->argv[argc++] = "--use-done-feature";
 404         if (data->export_marks)
 405                 fastexport->argv[argc++] = data->export_marks;
 406         if (data->import_marks)
 407                 fastexport->argv[argc++] = data->import_marks;
 408
 409         for (i = 0; i < revlist_args->nr; i++)
 410                 fastexport->argv[argc++] = revlist_args->items[i].string;
 411
 412         fastexport->git_cmd = 1;
 413         return start_command(fastexport);
 414 }
 415
 416 static int fetch_with_import(struct transport *transport,
 417                              int nr_heads, struct ref **to_fetch)
 418 {
 419         struct child_process fastimport;
 420         struct helper_data *data = transport->data;
 421         int i;
 422         struct ref *posn;
 423         struct strbuf buf = STRBUF_INIT;
 424
 425         get_helper(transport);
 426
 427         if (get_importer(transport, &fastimport))
 428                 die("Couldn't run fast-import");
 429
 430         for (i = 0; i < nr_heads; i++) {
 431                 posn = to_fetch[i];
 432                 if (posn->status & REF_STATUS_UPTODATE)
 433                         continue;
 434
 435                 strbuf_addf(&buf, "import %s\n", posn->name);
 436                 sendline(data, &buf);
 437                 strbuf_reset(&buf);
 438         }
 439
 440         write_constant(data->helper->in, "\n");
 441
 442         if (finish_command(&fastimport))
 443                 die("Error while running fast-import");
 444         free(fastimport.argv);
 445         fastimport.argv = NULL;
 446
 447         /*
 448          * The fast-import stream of a remote helper that advertises
 449          * the "refspec" capability writes to the refs named after the
 450          * right hand side of the first refspec matching each ref we
 451          * were fetching.
 452          *
 453          * (If no "refspec" capability was specified, for historical
 454          * reasons we default to *:*.)
 455          *
 456          * Store the result in to_fetch[i].old_sha1.  Callers such
 457          * as "git fetch" can use the value to write feedback to the
 458          * terminal, populate FETCH_HEAD, and determine what new value
 459          * should be written to peer_ref if the update is a
 460          * fast-forward or this is a forced update.
 461          */
 462         for (i = 0; i < nr_heads; i++) {
 463                 char *private;
 464                 posn = to_fetch[i];
 465                 if (posn->status & REF_STATUS_UPTODATE)
 466                         continue;
 467                 if (data->refspecs)
 468                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 469                 else
 470                         private = xstrdup(posn->name);
 471                 if (private) {
 472                         read_ref(private, posn->old_sha1);
 473                         free(private);
 474                 }
 475         }
 476         strbuf_release(&buf);
 477         return 0;
 478 }
 479
 480 static int process_connect_service(struct transport *transport,
 481                                    const char *name, const char *exec)
 482 {
 483         struct helper_data *data = transport->data;
 484         struct strbuf cmdbuf = STRBUF_INIT;
 485         struct child_process *helper;
 486         int r, duped, ret = 0;
 487         FILE *input;
 488
 489         helper = get_helper(transport);
 490
 491         /*
 492          * Yes, dup the pipe another time, as we need unbuffered version
 493          * of input pipe as FILE*. fclose() closes the underlying fd and
 494          * stream buffering only can be changed before first I/O operation
 495          * on it.
 496          */
 497         duped = dup(helper->out);
 498         if (duped < 0)
 499                 die_errno("Can't dup helper output fd");
 500         input = xfdopen(duped, "r");
 501         setvbuf(input, NULL, _IONBF, 0);
 502
 503         /*
 504          * Handle --upload-pack and friends. This is fire and forget...
 505          * just warn if it fails.
 506          */
 507         if (strcmp(name, exec)) {
 508                 r = set_helper_option(transport, "servpath", exec);
 509                 if (r > 0)
 510                         warning("Setting remote service path not supported by protocol.");
 511                 else if (r < 0)
 512                         warning("Invalid remote service path.");
 513         }
 514
 515         if (data->connect)
 516                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 517         else
 518                 goto exit;
 519
 520         sendline(data, &cmdbuf);
 521         recvline_fh(input, &cmdbuf);
 522         if (!strcmp(cmdbuf.buf, "")) {
 523                 data->no_disconnect_req = 1;
 524                 if (debug)
 525                         fprintf(stderr, "Debug: Smart transport connection "
 526                                 "ready.\n");
 527                 ret = 1;
 528         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 529                 if (debug)
 530                         fprintf(stderr, "Debug: Falling back to dumb "
 531                                 "transport.\n");
 532         } else
 533                 die("Unknown response to connect: %s",
 534                         cmdbuf.buf);
 535
 536 exit:
 537         fclose(input);
 538         return ret;
 539 }
 540
 541 static int process_connect(struct transport *transport,
 542                                      int for_push)
 543 {
 544         struct helper_data *data = transport->data;
 545         const char *name;
 546         const char *exec;
 547
 548         name = for_push ? "git-receive-pack" : "git-upload-pack";
 549         if (for_push)
 550                 exec = data->transport_options.receivepack;
 551         else
 552                 exec = data->transport_options.uploadpack;
 553
 554         return process_connect_service(transport, name, exec);
 555 }
 556
 557 static int connect_helper(struct transport *transport, const char *name,
 558                    const char *exec, int fd[2])
 559 {
 560         struct helper_data *data = transport->data;
 561
 562         /* Get_helper so connect is inited. */
 563         get_helper(transport);
 564         if (!data->connect)
 565                 die("Operation not supported by protocol.");
 566
 567         if (!process_connect_service(transport, name, exec))
 568                 die("Can't connect to subservice %s.", name);
 569
 570         fd[0] = data->helper->out;
 571         fd[1] = data->helper->in;
 572         return 0;
 573 }
 574
 575 static int fetch(struct transport *transport,
 576                  int nr_heads, struct ref **to_fetch)
 577 {
 578         struct helper_data *data = transport->data;
 579         int i, count;
 580
 581         if (process_connect(transport, 0)) {
 582                 do_take_over(transport);
 583                 return transport->fetch(transport, nr_heads, to_fetch);
 584         }
 585
 586         count = 0;
 587         for (i = 0; i < nr_heads; i++)
 588                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 589                         count++;
 590
 591         if (!count)
 592                 return 0;
 593
 594         if (data->fetch)
 595                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 596
 597         if (data->import)
 598                 return fetch_with_import(transport, nr_heads, to_fetch);
 599
 600         return -1;
 601 }
 602
 603 static void push_update_ref_status(struct strbuf *buf,
 604                                    struct ref **ref,
 605                                    struct ref *remote_refs)
 606 {
 607         char *refname, *msg;
 608         int status;
 609
 610         if (!prefixcmp(buf->buf, "ok ")) {
 611                 status = REF_STATUS_OK;
 612                 refname = buf->buf + 3;
 613         } else if (!prefixcmp(buf->buf, "error ")) {
 614                 status = REF_STATUS_REMOTE_REJECT;
 615                 refname = buf->buf + 6;
 616         } else
 617                 die("expected ok/error, helper said '%s'", buf->buf);
 618
 619         msg = strchr(refname, ' ');
 620         if (msg) {
 621                 struct strbuf msg_buf = STRBUF_INIT;
 622                 const char *end;
 623
 624                 *msg++ = '\0';
 625                 if (!unquote_c_style(&msg_buf, msg, &end))
 626                         msg = strbuf_detach(&msg_buf, NULL);
 627                 else
 628                         msg = xstrdup(msg);
 629                 strbuf_release(&msg_buf);
 630
 631                 if (!strcmp(msg, "no match")) {
 632                         status = REF_STATUS_NONE;
 633                         free(msg);
 634                         msg = NULL;
 635                 }
 636                 else if (!strcmp(msg, "up to date")) {
 637                         status = REF_STATUS_UPTODATE;
 638                         free(msg);
 639                         msg = NULL;
 640                 }
 641                 else if (!strcmp(msg, "non-fast forward")) {
 642                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 643                         free(msg);
 644                         msg = NULL;
 645                 }
 646         }
 647
 648         if (*ref)
 649                 *ref = find_ref_by_name(*ref, refname);
 650         if (!*ref)
 651                 *ref = find_ref_by_name(remote_refs, refname);
 652         if (!*ref) {
 653                 warning("helper reported unexpected status of %s", refname);
 654                 return;
 655         }
 656
 657         if ((*ref)->status != REF_STATUS_NONE) {
 658                 /*
 659                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 660                  * status reported by the remote helper if the latter is 'no match'.
 661                  */
 662                 if (status == REF_STATUS_NONE)
 663                         return;
 664         }
 665
 666         (*ref)->status = status;
 667         (*ref)->remote_status = msg;
 668 }
 669
 670 static void push_update_refs_status(struct helper_data *data,
 671                                     struct ref *remote_refs)
 672 {
 673         struct strbuf buf = STRBUF_INIT;
 674         struct ref *ref = remote_refs;
 675         for (;;) {
 676                 recvline(data, &buf);
 677                 if (!buf.len)
 678                         break;
 679
 680                 push_update_ref_status(&buf, &ref, remote_refs);
 681         }
 682         strbuf_release(&buf);
 683 }
 684
 685 static int push_refs_with_push(struct transport *transport,
 686                 struct ref *remote_refs, int flags)
 687 {
 688         int force_all = flags & TRANSPORT_PUSH_FORCE;
 689         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 690         struct helper_data *data = transport->data;
 691         struct strbuf buf = STRBUF_INIT;
 692         struct ref *ref;
 693
 694         get_helper(transport);
 695         if (!data->push)
 696                 return 1;
 697
 698         for (ref = remote_refs; ref; ref = ref->next) {
 699                 if (!ref->peer_ref && !mirror)
 700                         continue;
 701
 702                 /* Check for statuses set by set_ref_status_for_push() */
 703                 switch (ref->status) {
 704                 case REF_STATUS_REJECT_NONFASTFORWARD:
 705                 case REF_STATUS_UPTODATE:
 706                         continue;
 707                 default:
 708                         ; /* do nothing */
 709                 }
 710
 711                 if (force_all)
 712                         ref->force = 1;
 713
 714                 strbuf_addstr(&buf, "push ");
 715                 if (!ref->deletion) {
 716                         if (ref->force)
 717                                 strbuf_addch(&buf, '+');
 718                         if (ref->peer_ref)
 719                                 strbuf_addstr(&buf, ref->peer_ref->name);
 720                         else
 721                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 722                 }
 723                 strbuf_addch(&buf, ':');
 724                 strbuf_addstr(&buf, ref->name);
 725                 strbuf_addch(&buf, '\n');
 726         }
 727         if (buf.len == 0)
 728                 return 0;
 729
 730         standard_options(transport);
 731
 732         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 733                 if (set_helper_option(transport, "dry-run", "true") != 0)
 734                         die("helper %s does not support dry-run", data->name);
 735         }
 736
 737         strbuf_addch(&buf, '\n');
 738         sendline(data, &buf);
 739         strbuf_release(&buf);
 740
 741         push_update_refs_status(data, remote_refs);
 742         return 0;
 743 }
 744
 745 static int push_refs_with_export(struct transport *transport,
 746                 struct ref *remote_refs, int flags)
 747 {
 748         struct ref *ref;
 749         struct child_process *helper, exporter;
 750         struct helper_data *data = transport->data;
 751         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 752         struct strbuf buf = STRBUF_INIT;
 753
 754         helper = get_helper(transport);
 755
 756         write_constant(helper->in, "export\n");
 757
 758         strbuf_reset(&buf);
 759
 760         for (ref = remote_refs; ref; ref = ref->next) {
 761                 char *private;
 762                 unsigned char sha1[20];
 763
 764                 if (!data->refspecs)
 765                         continue;
 766                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 767                 if (private && !get_sha1(private, sha1)) {
 768                         strbuf_addf(&buf, "^%s", private);
 769                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 770                 }
 771                 free(private);
 772
 773                 if (ref->deletion) {
 774                         die("remote-helpers do not support ref deletion");
 775                 }
 776
 777                 if (ref->peer_ref)
 778                         string_list_append(&revlist_args, ref->peer_ref->name);
 779
 780         }
 781
 782         if (get_exporter(transport, &exporter, &revlist_args))
 783                 die("Couldn't run fast-export");
 784
 785         if (finish_command(&exporter))
 786                 die("Error while running fast-export");
 787         push_update_refs_status(data, remote_refs);
 788         return 0;
 789 }
 790
 791 static int push_refs(struct transport *transport,
 792                 struct ref *remote_refs, int flags)
 793 {
 794         struct helper_data *data = transport->data;
 795
 796         if (process_connect(transport, 1)) {
 797                 do_take_over(transport);
 798                 return transport->push_refs(transport, remote_refs, flags);
 799         }
 800
 801         if (!remote_refs) {
 802                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 803                         "Perhaps you should specify a branch such as 'master'.\n");
 804                 return 0;
 805         }
 806
 807         if (data->push)
 808                 return push_refs_with_push(transport, remote_refs, flags);
 809
 810         if (data->export)
 811                 return push_refs_with_export(transport, remote_refs, flags);
 812
 813         return -1;
 814 }
 815
 816
 817 static int has_attribute(const char *attrs, const char *attr) {
 818         int len;
 819         if (!attrs)
 820                 return 0;
 821
 822         len = strlen(attr);
 823         for (;;) {
 824                 const char *space = strchrnul(attrs, ' ');
 825                 if (len == space - attrs && !strncmp(attrs, attr, len))
 826                         return 1;
 827                 if (!*space)
 828                         return 0;
 829                 attrs = space + 1;
 830         }
 831 }
 832
 833 static struct ref *get_refs_list(struct transport *transport, int for_push)
 834 {
 835         struct helper_data *data = transport->data;
 836         struct child_process *helper;
 837         struct ref *ret = NULL;
 838         struct ref **tail = &ret;
 839         struct ref *posn;
 840         struct strbuf buf = STRBUF_INIT;
 841
 842         helper = get_helper(transport);
 843
 844         if (process_connect(transport, for_push)) {
 845                 do_take_over(transport);
 846                 return transport->get_refs_list(transport, for_push);
 847         }
 848
 849         if (data->push && for_push)
 850                 write_str_in_full(helper->in, "list for-push\n");
 851         else
 852                 write_str_in_full(helper->in, "list\n");
 853
 854         while (1) {
 855                 char *eov, *eon;
 856                 recvline(data, &buf);
 857
 858                 if (!*buf.buf)
 859                         break;
 860
 861                 eov = strchr(buf.buf, ' ');
 862                 if (!eov)
 863                         die("Malformed response in ref list: %s", buf.buf);
 864                 eon = strchr(eov + 1, ' ');
 865                 *eov = '\0';
 866                 if (eon)
 867                         *eon = '\0';
 868                 *tail = alloc_ref(eov + 1);
 869                 if (buf.buf[0] == '@')
 870                         (*tail)->symref = xstrdup(buf.buf + 1);
 871                 else if (buf.buf[0] != '?')
 872                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 873                 if (eon) {
 874                         if (has_attribute(eon + 1, "unchanged")) {
 875                                 (*tail)->status |= REF_STATUS_UPTODATE;
 876                                 read_ref((*tail)->name, (*tail)->old_sha1);
 877                         }
 878                 }
 879                 tail = &((*tail)->next);
 880         }
 881         if (debug)
 882                 fprintf(stderr, "Debug: Read ref listing.\n");
 883         strbuf_release(&buf);
 884
 885         for (posn = ret; posn; posn = posn->next)
 886                 resolve_remote_symref(posn, ret);
 887
 888         return ret;
 889 }
 890
 891 int transport_helper_init(struct transport *transport, const char *name)
 892 {
 893         struct helper_data *data = xcalloc(sizeof(*data), 1);
 894         data->name = name;
 895
 896         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 897                 debug = 1;
 898
 899         transport->data = data;
 900         transport->set_option = set_helper_option;
 901         transport->get_refs_list = get_refs_list;
 902         transport->fetch = fetch;
 903         transport->push_refs = push_refs;
 904         transport->disconnect = release_helper;
 905         transport->connect = connect_helper;
 906         transport->smart_options = &(data->transport_options);
 907         return 0;
 908 }
 909
 910 /*
 911  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 912  * buffer less), so attempt reads and writes with up to that size.
 913  */
 914 #define BUFFERSIZE 65536
 915 /* This should be enough to hold debugging message. */
 916 #define PBUFFERSIZE 8192
 917
 918 /* Print bidirectional transfer loop debug message. */
 919 static void transfer_debug(const char *fmt, ...)
 920 {
 921         va_list args;
 922         char msgbuf[PBUFFERSIZE];
 923         static int debug_enabled = -1;
 924
 925         if (debug_enabled < 0)
 926                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 927         if (!debug_enabled)
 928                 return;
 929
 930         va_start(args, fmt);
 931         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 932         va_end(args);
 933         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 934 }
 935
 936 /* Stream state: More data may be coming in this direction. */
 937 #define SSTATE_TRANSFERING 0
 938 /*
 939  * Stream state: No more data coming in this direction, flushing rest of
 940  * data.
 941  */
 942 #define SSTATE_FLUSHING 1
 943 /* Stream state: Transfer in this direction finished. */
 944 #define SSTATE_FINISHED 2
 945
 946 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 947 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 948 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 949
 950 /* Unidirectional transfer. */
 951 struct unidirectional_transfer {
 952         /* Source */
 953         int src;
 954         /* Destination */
 955         int dest;
 956         /* Is source socket? */
 957         int src_is_sock;
 958         /* Is destination socket? */
 959         int dest_is_sock;
 960         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 961         int state;
 962         /* Buffer. */
 963         char buf[BUFFERSIZE];
 964         /* Buffer used. */
 965         size_t bufuse;
 966         /* Name of source. */
 967         const char *src_name;
 968         /* Name of destination. */
 969         const char *dest_name;
 970 };
 971
 972 /* Closes the target (for writing) if transfer has finished. */
 973 static void udt_close_if_finished(struct unidirectional_transfer *t)
 974 {
 975         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 976                 t->state = SSTATE_FINISHED;
 977                 if (t->dest_is_sock)
 978                         shutdown(t->dest, SHUT_WR);
 979                 else
 980                         close(t->dest);
 981                 transfer_debug("Closed %s.", t->dest_name);
 982         }
 983 }
 984
 985 /*
 986  * Tries to read read data from source into buffer. If buffer is full,
 987  * no data is read. Returns 0 on success, -1 on error.
 988  */
 989 static int udt_do_read(struct unidirectional_transfer *t)
 990 {
 991         ssize_t bytes;
 992
 993         if (t->bufuse == BUFFERSIZE)
 994                 return 0;       /* No space for more. */
 995
 996         transfer_debug("%s is readable", t->src_name);
 997         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 998         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 999                 errno != EINTR) {
1000                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1001                 return -1;
1002         } else if (bytes == 0) {
1003                 transfer_debug("%s EOF (with %i bytes in buffer)",
1004                         t->src_name, t->bufuse);
1005                 t->state = SSTATE_FLUSHING;
1006         } else if (bytes > 0) {
1007                 t->bufuse += bytes;
1008                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1009                         (int)bytes, t->src_name, (int)t->bufuse);
1010         }
1011         return 0;
1012 }
1013
1014 /* Tries to write data from buffer into destination. If buffer is empty,
1015  * no data is written. Returns 0 on success, -1 on error.
1016  */
1017 static int udt_do_write(struct unidirectional_transfer *t)
1018 {
1019         ssize_t bytes;
1020
1021         if (t->bufuse == 0)
1022                 return 0;       /* Nothing to write. */
1023
1024         transfer_debug("%s is writable", t->dest_name);
1025         bytes = write(t->dest, t->buf, t->bufuse);
1026         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1027                 errno != EINTR) {
1028                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1029                 return -1;
1030         } else if (bytes > 0) {
1031                 t->bufuse -= bytes;
1032                 if (t->bufuse)
1033                         memmove(t->buf, t->buf + bytes, t->bufuse);
1034                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1035                         (int)bytes, t->dest_name, (int)t->bufuse);
1036         }
1037         return 0;
1038 }
1039
1040
1041 /* State of bidirectional transfer loop. */
1042 struct bidirectional_transfer_state {
1043         /* Direction from program to git. */
1044         struct unidirectional_transfer ptg;
1045         /* Direction from git to program. */
1046         struct unidirectional_transfer gtp;
1047 };
1048
1049 static void *udt_copy_task_routine(void *udt)
1050 {
1051         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1052         while (t->state != SSTATE_FINISHED) {
1053                 if (STATE_NEEDS_READING(t->state))
1054                         if (udt_do_read(t))
1055                                 return NULL;
1056                 if (STATE_NEEDS_WRITING(t->state))
1057                         if (udt_do_write(t))
1058                                 return NULL;
1059                 if (STATE_NEEDS_CLOSING(t->state))
1060                         udt_close_if_finished(t);
1061         }
1062         return udt;     /* Just some non-NULL value. */
1063 }
1064
1065 #ifndef NO_PTHREADS
1066
1067 /*
1068  * Join thread, with apporiate errors on failure. Name is name for the
1069  * thread (for error messages). Returns 0 on success, 1 on failure.
1070  */
1071 static int tloop_join(pthread_t thread, const char *name)
1072 {
1073         int err;
1074         void *tret;
1075         err = pthread_join(thread, &tret);
1076         if (!tret) {
1077                 error("%s thread failed", name);
1078                 return 1;
1079         }
1080         if (err) {
1081                 error("%s thread failed to join: %s", name, strerror(err));
1082                 return 1;
1083         }
1084         return 0;
1085 }
1086
1087 /*
1088  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1089  * -1 on failure.
1090  */
1091 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1092 {
1093         pthread_t gtp_thread;
1094         pthread_t ptg_thread;
1095         int err;
1096         int ret = 0;
1097         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1098                 &s->gtp);
1099         if (err)
1100                 die("Can't start thread for copying data: %s", strerror(err));
1101         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1102                 &s->ptg);
1103         if (err)
1104                 die("Can't start thread for copying data: %s", strerror(err));
1105
1106         ret |= tloop_join(gtp_thread, "Git to program copy");
1107         ret |= tloop_join(ptg_thread, "Program to git copy");
1108         return ret;
1109 }
1110 #else
1111
1112 /* Close the source and target (for writing) for transfer. */
1113 static void udt_kill_transfer(struct unidirectional_transfer *t)
1114 {
1115         t->state = SSTATE_FINISHED;
1116         /*
1117          * Socket read end left open isn't a disaster if nobody
1118          * attempts to read from it (mingw compat headers do not
1119          * have SHUT_RD)...
1120          *
1121          * We can't fully close the socket since otherwise gtp
1122          * task would first close the socket it sends data to
1123          * while closing the ptg file descriptors.
1124          */
1125         if (!t->src_is_sock)
1126                 close(t->src);
1127         if (t->dest_is_sock)
1128                 shutdown(t->dest, SHUT_WR);
1129         else
1130                 close(t->dest);
1131 }
1132
1133 /*
1134  * Join process, with apporiate errors on failure. Name is name for the
1135  * process (for error messages). Returns 0 on success, 1 on failure.
1136  */
1137 static int tloop_join(pid_t pid, const char *name)
1138 {
1139         int tret;
1140         if (waitpid(pid, &tret, 0) < 0) {
1141                 error("%s process failed to wait: %s", name, strerror(errno));
1142                 return 1;
1143         }
1144         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1145                 error("%s process failed", name);
1146                 return 1;
1147         }
1148         return 0;
1149 }
1150
1151 /*
1152  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1153  * -1 on failure.
1154  */
1155 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1156 {
1157         pid_t pid1, pid2;
1158         int ret = 0;
1159
1160         /* Fork thread #1: git to program. */
1161         pid1 = fork();
1162         if (pid1 < 0)
1163                 die_errno("Can't start thread for copying data");
1164         else if (pid1 == 0) {
1165                 udt_kill_transfer(&s->ptg);
1166                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1167         }
1168
1169         /* Fork thread #2: program to git. */
1170         pid2 = fork();
1171         if (pid2 < 0)
1172                 die_errno("Can't start thread for copying data");
1173         else if (pid2 == 0) {
1174                 udt_kill_transfer(&s->gtp);
1175                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1176         }
1177
1178         /*
1179          * Close both streams in parent as to not interfere with
1180          * end of file detection and wait for both tasks to finish.
1181          */
1182         udt_kill_transfer(&s->gtp);
1183         udt_kill_transfer(&s->ptg);
1184         ret |= tloop_join(pid1, "Git to program copy");
1185         ret |= tloop_join(pid2, "Program to git copy");
1186         return ret;
1187 }
1188 #endif
1189
1190 /*
1191  * Copies data from stdin to output and from input to stdout simultaneously.
1192  * Additionally filtering through given filter. If filter is NULL, uses
1193  * identity filter.
1194  */
1195 int bidirectional_transfer_loop(int input, int output)
1196 {
1197         struct bidirectional_transfer_state state;
1198
1199         /* Fill the state fields. */
1200         state.ptg.src = input;
1201         state.ptg.dest = 1;
1202         state.ptg.src_is_sock = (input == output);
1203         state.ptg.dest_is_sock = 0;
1204         state.ptg.state = SSTATE_TRANSFERING;
1205         state.ptg.bufuse = 0;
1206         state.ptg.src_name = "remote input";
1207         state.ptg.dest_name = "stdout";
1208
1209         state.gtp.src = 0;
1210         state.gtp.dest = output;
1211         state.gtp.src_is_sock = 0;
1212         state.gtp.dest_is_sock = (input == output);
1213         state.gtp.state = SSTATE_TRANSFERING;
1214         state.gtp.bufuse = 0;
1215         state.gtp.src_name = "stdin";
1216         state.gtp.dest_name = "remote output";
1217
1218         return tloop_spawnwait_tasks(&state);
1219 }