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 #include "sigchain.h"
  13 #include "argv-array.h"
  14
  15 static int debug;
  16
  17 struct helper_data {
  18         const char *name;
  19         struct child_process *helper;
  20         FILE *out;
  21         unsigned fetch : 1,
  22                 import : 1,
  23                 bidi_import : 1,
  24                 export : 1,
  25                 option : 1,
  26                 push : 1,
  27                 connect : 1,
  28                 no_disconnect_req : 1;
  29         char *export_marks;
  30         char *import_marks;
  31         /* These go from remote name (as in "list") to private name */
  32         struct refspec *refspecs;
  33         int refspec_nr;
  34         /* Transport options for fetch-pack/send-pack (should one of
  35          * those be invoked).
  36          */
  37         struct git_transport_options transport_options;
  38 };
  39
  40 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  41 {
  42         if (debug)
  43                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  44         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  45                 != buffer->len)
  46                 die_errno("Full write to remote helper failed");
  47 }
  48
  49 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  50 {
  51         strbuf_reset(buffer);
  52         if (debug)
  53                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  54         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  55                 if (debug)
  56                         fprintf(stderr, "Debug: Remote helper quit.\n");
  57                 exit(128);
  58         }
  59
  60         if (debug)
  61                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  62         return 0;
  63 }
  64
  65 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  66 {
  67         return recvline_fh(helper->out, buffer);
  68 }
  69
  70 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  71 {
  72         sendline(helper, buffer);
  73         recvline(helper, buffer);
  74 }
  75
  76 static void write_constant(int fd, const char *str)
  77 {
  78         if (debug)
  79                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  80         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  81                 die_errno("Full write to remote helper failed");
  82 }
  83
  84 static const char *remove_ext_force(const char *url)
  85 {
  86         if (url) {
  87                 const char *colon = strchr(url, ':');
  88                 if (colon && colon[1] == ':')
  89                         return colon + 2;
  90         }
  91         return url;
  92 }
  93
  94 static void do_take_over(struct transport *transport)
  95 {
  96         struct helper_data *data;
  97         data = (struct helper_data *)transport->data;
  98         transport_take_over(transport, data->helper);
  99         fclose(data->out);
 100         free(data);
 101 }
 102
 103 static struct child_process *get_helper(struct transport *transport)
 104 {
 105         struct helper_data *data = transport->data;
 106         struct argv_array argv = ARGV_ARRAY_INIT;
 107         struct strbuf buf = STRBUF_INIT;
 108         struct child_process *helper;
 109         const char **refspecs = NULL;
 110         int refspec_nr = 0;
 111         int refspec_alloc = 0;
 112         int duped;
 113         int code;
 114         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 115         const char *helper_env[] = {
 116                 git_dir_buf,
 117                 NULL
 118         };
 119
 120
 121         if (data->helper)
 122                 return data->helper;
 123
 124         helper = xcalloc(1, sizeof(*helper));
 125         helper->in = -1;
 126         helper->out = -1;
 127         helper->err = 0;
 128         argv_array_pushf(&argv, "git-remote-%s", data->name);
 129         argv_array_push(&argv, transport->remote->name);
 130         argv_array_push(&argv, remove_ext_force(transport->url));
 131         helper->argv = argv_array_detach(&argv, NULL);
 132         helper->git_cmd = 0;
 133         helper->silent_exec_failure = 1;
 134
 135         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 136         helper->env = helper_env;
 137
 138         code = start_command(helper);
 139         if (code < 0 && errno == ENOENT)
 140                 die("Unable to find remote helper for '%s'", data->name);
 141         else if (code != 0)
 142                 exit(code);
 143
 144         data->helper = helper;
 145         data->no_disconnect_req = 0;
 146
 147         /*
 148          * Open the output as FILE* so strbuf_getline() can be used.
 149          * Do this with duped fd because fclose() will close the fd,
 150          * and stuff like taking over will require the fd to remain.
 151          */
 152         duped = dup(helper->out);
 153         if (duped < 0)
 154                 die_errno("Can't dup helper output fd");
 155         data->out = xfdopen(duped, "r");
 156
 157         write_constant(helper->in, "capabilities\n");
 158
 159         while (1) {
 160                 const char *capname;
 161                 int mandatory = 0;
 162                 recvline(data, &buf);
 163
 164                 if (!*buf.buf)
 165                         break;
 166
 167                 if (*buf.buf == '*') {
 168                         capname = buf.buf + 1;
 169                         mandatory = 1;
 170                 } else
 171                         capname = buf.buf;
 172
 173                 if (debug)
 174                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 175                 if (!strcmp(capname, "fetch"))
 176                         data->fetch = 1;
 177                 else if (!strcmp(capname, "option"))
 178                         data->option = 1;
 179                 else if (!strcmp(capname, "push"))
 180                         data->push = 1;
 181                 else if (!strcmp(capname, "import"))
 182                         data->import = 1;
 183                 else if (!strcmp(capname, "bidi-import"))
 184                         data->bidi_import = 1;
 185                 else if (!strcmp(capname, "export"))
 186                         data->export = 1;
 187                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 188                         ALLOC_GROW(refspecs,
 189                                    refspec_nr + 1,
 190                                    refspec_alloc);
 191                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 192                 } else if (!strcmp(capname, "connect")) {
 193                         data->connect = 1;
 194                 } else if (!prefixcmp(capname, "export-marks ")) {
 195                         struct strbuf arg = STRBUF_INIT;
 196                         strbuf_addstr(&arg, "--export-marks=");
 197                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 198                         data->export_marks = strbuf_detach(&arg, NULL);
 199                 } else if (!prefixcmp(capname, "import-marks")) {
 200                         struct strbuf arg = STRBUF_INIT;
 201                         strbuf_addstr(&arg, "--import-marks=");
 202                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 203                         data->import_marks = strbuf_detach(&arg, NULL);
 204                 } else if (mandatory) {
 205                         die("Unknown mandatory capability %s. This remote "
 206                             "helper probably needs newer version of Git.",
 207                             capname);
 208                 }
 209         }
 210         if (refspecs) {
 211                 int i;
 212                 data->refspec_nr = refspec_nr;
 213                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 214                 for (i = 0; i < refspec_nr; i++) {
 215                         free((char *)refspecs[i]);
 216                 }
 217                 free(refspecs);
 218         }
 219         strbuf_release(&buf);
 220         if (debug)
 221                 fprintf(stderr, "Debug: Capabilities complete.\n");
 222         return data->helper;
 223 }
 224
 225 static int disconnect_helper(struct transport *transport)
 226 {
 227         struct helper_data *data = transport->data;
 228         int res = 0;
 229
 230         if (data->helper) {
 231                 if (debug)
 232                         fprintf(stderr, "Debug: Disconnecting.\n");
 233                 if (!data->no_disconnect_req) {
 234                         /*
 235                          * Ignore write errors; there's nothing we can do,
 236                          * since we're about to close the pipe anyway. And the
 237                          * most likely error is EPIPE due to the helper dying
 238                          * to report an error itself.
 239                          */
 240                         sigchain_push(SIGPIPE, SIG_IGN);
 241                         xwrite(data->helper->in, "\n", 1);
 242                         sigchain_pop(SIGPIPE);
 243                 }
 244                 close(data->helper->in);
 245                 close(data->helper->out);
 246                 fclose(data->out);
 247                 res = finish_command(data->helper);
 248                 argv_array_free_detached(data->helper->argv);
 249                 free(data->helper);
 250                 data->helper = NULL;
 251         }
 252         return res;
 253 }
 254
 255 static const char *unsupported_options[] = {
 256         TRANS_OPT_UPLOADPACK,
 257         TRANS_OPT_RECEIVEPACK,
 258         TRANS_OPT_THIN,
 259         TRANS_OPT_KEEP
 260         };
 261 static const char *boolean_options[] = {
 262         TRANS_OPT_THIN,
 263         TRANS_OPT_KEEP,
 264         TRANS_OPT_FOLLOWTAGS
 265         };
 266
 267 static int set_helper_option(struct transport *transport,
 268                           const char *name, const char *value)
 269 {
 270         struct helper_data *data = transport->data;
 271         struct strbuf buf = STRBUF_INIT;
 272         int i, ret, is_bool = 0;
 273
 274         get_helper(transport);
 275
 276         if (!data->option)
 277                 return 1;
 278
 279         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 280                 if (!strcmp(name, unsupported_options[i]))
 281                         return 1;
 282         }
 283
 284         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 285                 if (!strcmp(name, boolean_options[i])) {
 286                         is_bool = 1;
 287                         break;
 288                 }
 289         }
 290
 291         strbuf_addf(&buf, "option %s ", name);
 292         if (is_bool)
 293                 strbuf_addstr(&buf, value ? "true" : "false");
 294         else
 295                 quote_c_style(value, &buf, NULL, 0);
 296         strbuf_addch(&buf, '\n');
 297
 298         xchgline(data, &buf);
 299
 300         if (!strcmp(buf.buf, "ok"))
 301                 ret = 0;
 302         else if (!prefixcmp(buf.buf, "error")) {
 303                 ret = -1;
 304         } else if (!strcmp(buf.buf, "unsupported"))
 305                 ret = 1;
 306         else {
 307                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 308                 ret = 1;
 309         }
 310         strbuf_release(&buf);
 311         return ret;
 312 }
 313
 314 static void standard_options(struct transport *t)
 315 {
 316         char buf[16];
 317         int n;
 318         int v = t->verbose;
 319
 320         set_helper_option(t, "progress", t->progress ? "true" : "false");
 321
 322         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 323         if (n >= sizeof(buf))
 324                 die("impossibly large verbosity value");
 325         set_helper_option(t, "verbosity", buf);
 326 }
 327
 328 static int release_helper(struct transport *transport)
 329 {
 330         int res = 0;
 331         struct helper_data *data = transport->data;
 332         free_refspec(data->refspec_nr, data->refspecs);
 333         data->refspecs = NULL;
 334         res = disconnect_helper(transport);
 335         free(transport->data);
 336         return res;
 337 }
 338
 339 static int fetch_with_fetch(struct transport *transport,
 340                             int nr_heads, struct ref **to_fetch)
 341 {
 342         struct helper_data *data = transport->data;
 343         int i;
 344         struct strbuf buf = STRBUF_INIT;
 345
 346         standard_options(transport);
 347
 348         for (i = 0; i < nr_heads; i++) {
 349                 const struct ref *posn = to_fetch[i];
 350                 if (posn->status & REF_STATUS_UPTODATE)
 351                         continue;
 352
 353                 strbuf_addf(&buf, "fetch %s %s\n",
 354                             sha1_to_hex(posn->old_sha1), posn->name);
 355         }
 356
 357         strbuf_addch(&buf, '\n');
 358         sendline(data, &buf);
 359
 360         while (1) {
 361                 recvline(data, &buf);
 362
 363                 if (!prefixcmp(buf.buf, "lock ")) {
 364                         const char *name = buf.buf + 5;
 365                         if (transport->pack_lockfile)
 366                                 warning("%s also locked %s", data->name, name);
 367                         else
 368                                 transport->pack_lockfile = xstrdup(name);
 369                 }
 370                 else if (!buf.len)
 371                         break;
 372                 else
 373                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 374         }
 375         strbuf_release(&buf);
 376         return 0;
 377 }
 378
 379 static int get_importer(struct transport *transport, struct child_process *fastimport)
 380 {
 381         struct child_process *helper = get_helper(transport);
 382         struct helper_data *data = transport->data;
 383         struct argv_array argv = ARGV_ARRAY_INIT;
 384         int cat_blob_fd, code;
 385         memset(fastimport, 0, sizeof(*fastimport));
 386         fastimport->in = helper->out;
 387         argv_array_push(&argv, "fast-import");
 388         argv_array_push(&argv, debug ? "--stats" : "--quiet");
 389
 390         if (data->bidi_import) {
 391                 cat_blob_fd = xdup(helper->in);
 392                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 393         }
 394         fastimport->argv = argv.argv;
 395         fastimport->git_cmd = 1;
 396
 397         code = start_command(fastimport);
 398         return code;
 399 }
 400
 401 static int get_exporter(struct transport *transport,
 402                         struct child_process *fastexport,
 403                         struct string_list *revlist_args)
 404 {
 405         struct helper_data *data = transport->data;
 406         struct child_process *helper = get_helper(transport);
 407         int argc = 0, i;
 408         memset(fastexport, 0, sizeof(*fastexport));
 409
 410         /* we need to duplicate helper->in because we want to use it after
 411          * fastexport is done with it. */
 412         fastexport->out = dup(helper->in);
 413         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
 414         fastexport->argv[argc++] = "fast-export";
 415         fastexport->argv[argc++] = "--use-done-feature";
 416         if (data->export_marks)
 417                 fastexport->argv[argc++] = data->export_marks;
 418         if (data->import_marks)
 419                 fastexport->argv[argc++] = data->import_marks;
 420
 421         for (i = 0; i < revlist_args->nr; i++)
 422                 fastexport->argv[argc++] = revlist_args->items[i].string;
 423
 424         fastexport->git_cmd = 1;
 425         return start_command(fastexport);
 426 }
 427
 428 static int fetch_with_import(struct transport *transport,
 429                              int nr_heads, struct ref **to_fetch)
 430 {
 431         struct child_process fastimport;
 432         struct helper_data *data = transport->data;
 433         int i;
 434         struct ref *posn;
 435         struct strbuf buf = STRBUF_INIT;
 436
 437         get_helper(transport);
 438
 439         if (get_importer(transport, &fastimport))
 440                 die("Couldn't run fast-import");
 441
 442         for (i = 0; i < nr_heads; i++) {
 443                 posn = to_fetch[i];
 444                 if (posn->status & REF_STATUS_UPTODATE)
 445                         continue;
 446
 447                 strbuf_addf(&buf, "import %s\n", posn->name);
 448                 sendline(data, &buf);
 449                 strbuf_reset(&buf);
 450         }
 451
 452         write_constant(data->helper->in, "\n");
 453         /*
 454          * remote-helpers that advertise the bidi-import capability are required to
 455          * buffer the complete batch of import commands until this newline before
 456          * sending data to fast-import.
 457          * These helpers read back data from fast-import on their stdin, which could
 458          * be mixed with import commands, otherwise.
 459          */
 460
 461         if (finish_command(&fastimport))
 462                 die("Error while running fast-import");
 463         argv_array_free_detached(fastimport.argv);
 464
 465         /*
 466          * The fast-import stream of a remote helper that advertises
 467          * the "refspec" capability writes to the refs named after the
 468          * right hand side of the first refspec matching each ref we
 469          * were fetching.
 470          *
 471          * (If no "refspec" capability was specified, for historical
 472          * reasons we default to *:*.)
 473          *
 474          * Store the result in to_fetch[i].old_sha1.  Callers such
 475          * as "git fetch" can use the value to write feedback to the
 476          * terminal, populate FETCH_HEAD, and determine what new value
 477          * should be written to peer_ref if the update is a
 478          * fast-forward or this is a forced update.
 479          */
 480         for (i = 0; i < nr_heads; i++) {
 481                 char *private;
 482                 posn = to_fetch[i];
 483                 if (posn->status & REF_STATUS_UPTODATE)
 484                         continue;
 485                 if (data->refspecs)
 486                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 487                 else
 488                         private = xstrdup(posn->name);
 489                 if (private) {
 490                         read_ref(private, posn->old_sha1);
 491                         free(private);
 492                 }
 493         }
 494         strbuf_release(&buf);
 495         return 0;
 496 }
 497
 498 static int process_connect_service(struct transport *transport,
 499                                    const char *name, const char *exec)
 500 {
 501         struct helper_data *data = transport->data;
 502         struct strbuf cmdbuf = STRBUF_INIT;
 503         struct child_process *helper;
 504         int r, duped, ret = 0;
 505         FILE *input;
 506
 507         helper = get_helper(transport);
 508
 509         /*
 510          * Yes, dup the pipe another time, as we need unbuffered version
 511          * of input pipe as FILE*. fclose() closes the underlying fd and
 512          * stream buffering only can be changed before first I/O operation
 513          * on it.
 514          */
 515         duped = dup(helper->out);
 516         if (duped < 0)
 517                 die_errno("Can't dup helper output fd");
 518         input = xfdopen(duped, "r");
 519         setvbuf(input, NULL, _IONBF, 0);
 520
 521         /*
 522          * Handle --upload-pack and friends. This is fire and forget...
 523          * just warn if it fails.
 524          */
 525         if (strcmp(name, exec)) {
 526                 r = set_helper_option(transport, "servpath", exec);
 527                 if (r > 0)
 528                         warning("Setting remote service path not supported by protocol.");
 529                 else if (r < 0)
 530                         warning("Invalid remote service path.");
 531         }
 532
 533         if (data->connect)
 534                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 535         else
 536                 goto exit;
 537
 538         sendline(data, &cmdbuf);
 539         recvline_fh(input, &cmdbuf);
 540         if (!strcmp(cmdbuf.buf, "")) {
 541                 data->no_disconnect_req = 1;
 542                 if (debug)
 543                         fprintf(stderr, "Debug: Smart transport connection "
 544                                 "ready.\n");
 545                 ret = 1;
 546         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 547                 if (debug)
 548                         fprintf(stderr, "Debug: Falling back to dumb "
 549                                 "transport.\n");
 550         } else
 551                 die("Unknown response to connect: %s",
 552                         cmdbuf.buf);
 553
 554 exit:
 555         fclose(input);
 556         return ret;
 557 }
 558
 559 static int process_connect(struct transport *transport,
 560                                      int for_push)
 561 {
 562         struct helper_data *data = transport->data;
 563         const char *name;
 564         const char *exec;
 565
 566         name = for_push ? "git-receive-pack" : "git-upload-pack";
 567         if (for_push)
 568                 exec = data->transport_options.receivepack;
 569         else
 570                 exec = data->transport_options.uploadpack;
 571
 572         return process_connect_service(transport, name, exec);
 573 }
 574
 575 static int connect_helper(struct transport *transport, const char *name,
 576                    const char *exec, int fd[2])
 577 {
 578         struct helper_data *data = transport->data;
 579
 580         /* Get_helper so connect is inited. */
 581         get_helper(transport);
 582         if (!data->connect)
 583                 die("Operation not supported by protocol.");
 584
 585         if (!process_connect_service(transport, name, exec))
 586                 die("Can't connect to subservice %s.", name);
 587
 588         fd[0] = data->helper->out;
 589         fd[1] = data->helper->in;
 590         return 0;
 591 }
 592
 593 static int fetch(struct transport *transport,
 594                  int nr_heads, struct ref **to_fetch)
 595 {
 596         struct helper_data *data = transport->data;
 597         int i, count;
 598
 599         if (process_connect(transport, 0)) {
 600                 do_take_over(transport);
 601                 return transport->fetch(transport, nr_heads, to_fetch);
 602         }
 603
 604         count = 0;
 605         for (i = 0; i < nr_heads; i++)
 606                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 607                         count++;
 608
 609         if (!count)
 610                 return 0;
 611
 612         if (data->fetch)
 613                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 614
 615         if (data->import)
 616                 return fetch_with_import(transport, nr_heads, to_fetch);
 617
 618         return -1;
 619 }
 620
 621 static void push_update_ref_status(struct strbuf *buf,
 622                                    struct ref **ref,
 623                                    struct ref *remote_refs)
 624 {
 625         char *refname, *msg;
 626         int status;
 627
 628         if (!prefixcmp(buf->buf, "ok ")) {
 629                 status = REF_STATUS_OK;
 630                 refname = buf->buf + 3;
 631         } else if (!prefixcmp(buf->buf, "error ")) {
 632                 status = REF_STATUS_REMOTE_REJECT;
 633                 refname = buf->buf + 6;
 634         } else
 635                 die("expected ok/error, helper said '%s'", buf->buf);
 636
 637         msg = strchr(refname, ' ');
 638         if (msg) {
 639                 struct strbuf msg_buf = STRBUF_INIT;
 640                 const char *end;
 641
 642                 *msg++ = '\0';
 643                 if (!unquote_c_style(&msg_buf, msg, &end))
 644                         msg = strbuf_detach(&msg_buf, NULL);
 645                 else
 646                         msg = xstrdup(msg);
 647                 strbuf_release(&msg_buf);
 648
 649                 if (!strcmp(msg, "no match")) {
 650                         status = REF_STATUS_NONE;
 651                         free(msg);
 652                         msg = NULL;
 653                 }
 654                 else if (!strcmp(msg, "up to date")) {
 655                         status = REF_STATUS_UPTODATE;
 656                         free(msg);
 657                         msg = NULL;
 658                 }
 659                 else if (!strcmp(msg, "non-fast forward")) {
 660                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 661                         free(msg);
 662                         msg = NULL;
 663                 }
 664                 else if (!strcmp(msg, "already exists")) {
 665                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 666                         free(msg);
 667                         msg = NULL;
 668                 }
 669         }
 670
 671         if (*ref)
 672                 *ref = find_ref_by_name(*ref, refname);
 673         if (!*ref)
 674                 *ref = find_ref_by_name(remote_refs, refname);
 675         if (!*ref) {
 676                 warning("helper reported unexpected status of %s", refname);
 677                 return;
 678         }
 679
 680         if ((*ref)->status != REF_STATUS_NONE) {
 681                 /*
 682                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 683                  * status reported by the remote helper if the latter is 'no match'.
 684                  */
 685                 if (status == REF_STATUS_NONE)
 686                         return;
 687         }
 688
 689         (*ref)->status = status;
 690         (*ref)->remote_status = msg;
 691 }
 692
 693 static void push_update_refs_status(struct helper_data *data,
 694                                     struct ref *remote_refs)
 695 {
 696         struct strbuf buf = STRBUF_INIT;
 697         struct ref *ref = remote_refs;
 698         for (;;) {
 699                 recvline(data, &buf);
 700                 if (!buf.len)
 701                         break;
 702
 703                 push_update_ref_status(&buf, &ref, remote_refs);
 704         }
 705         strbuf_release(&buf);
 706 }
 707
 708 static int push_refs_with_push(struct transport *transport,
 709                 struct ref *remote_refs, int flags)
 710 {
 711         int force_all = flags & TRANSPORT_PUSH_FORCE;
 712         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 713         struct helper_data *data = transport->data;
 714         struct strbuf buf = STRBUF_INIT;
 715         struct ref *ref;
 716
 717         get_helper(transport);
 718         if (!data->push)
 719                 return 1;
 720
 721         for (ref = remote_refs; ref; ref = ref->next) {
 722                 if (!ref->peer_ref && !mirror)
 723                         continue;
 724
 725                 /* Check for statuses set by set_ref_status_for_push() */
 726                 switch (ref->status) {
 727                 case REF_STATUS_REJECT_NONFASTFORWARD:
 728                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 729                 case REF_STATUS_UPTODATE:
 730                         continue;
 731                 default:
 732                         ; /* do nothing */
 733                 }
 734
 735                 if (force_all)
 736                         ref->force = 1;
 737
 738                 strbuf_addstr(&buf, "push ");
 739                 if (!ref->deletion) {
 740                         if (ref->force)
 741                                 strbuf_addch(&buf, '+');
 742                         if (ref->peer_ref)
 743                                 strbuf_addstr(&buf, ref->peer_ref->name);
 744                         else
 745                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 746                 }
 747                 strbuf_addch(&buf, ':');
 748                 strbuf_addstr(&buf, ref->name);
 749                 strbuf_addch(&buf, '\n');
 750         }
 751         if (buf.len == 0)
 752                 return 0;
 753
 754         standard_options(transport);
 755
 756         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 757                 if (set_helper_option(transport, "dry-run", "true") != 0)
 758                         die("helper %s does not support dry-run", data->name);
 759         }
 760
 761         strbuf_addch(&buf, '\n');
 762         sendline(data, &buf);
 763         strbuf_release(&buf);
 764
 765         push_update_refs_status(data, remote_refs);
 766         return 0;
 767 }
 768
 769 static int push_refs_with_export(struct transport *transport,
 770                 struct ref *remote_refs, int flags)
 771 {
 772         struct ref *ref;
 773         struct child_process *helper, exporter;
 774         struct helper_data *data = transport->data;
 775         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 776         struct strbuf buf = STRBUF_INIT;
 777
 778         helper = get_helper(transport);
 779
 780         write_constant(helper->in, "export\n");
 781
 782         strbuf_reset(&buf);
 783
 784         for (ref = remote_refs; ref; ref = ref->next) {
 785                 char *private;
 786                 unsigned char sha1[20];
 787
 788                 if (!data->refspecs)
 789                         continue;
 790                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 791                 if (private && !get_sha1(private, sha1)) {
 792                         strbuf_addf(&buf, "^%s", private);
 793                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 794                 }
 795                 free(private);
 796
 797                 if (ref->deletion) {
 798                         die("remote-helpers do not support ref deletion");
 799                 }
 800
 801                 if (ref->peer_ref)
 802                         string_list_append(&revlist_args, ref->peer_ref->name);
 803
 804         }
 805
 806         if (get_exporter(transport, &exporter, &revlist_args))
 807                 die("Couldn't run fast-export");
 808
 809         if (finish_command(&exporter))
 810                 die("Error while running fast-export");
 811         push_update_refs_status(data, remote_refs);
 812         return 0;
 813 }
 814
 815 static int push_refs(struct transport *transport,
 816                 struct ref *remote_refs, int flags)
 817 {
 818         struct helper_data *data = transport->data;
 819
 820         if (process_connect(transport, 1)) {
 821                 do_take_over(transport);
 822                 return transport->push_refs(transport, remote_refs, flags);
 823         }
 824
 825         if (!remote_refs) {
 826                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 827                         "Perhaps you should specify a branch such as 'master'.\n");
 828                 return 0;
 829         }
 830
 831         if (data->push)
 832                 return push_refs_with_push(transport, remote_refs, flags);
 833
 834         if (data->export)
 835                 return push_refs_with_export(transport, remote_refs, flags);
 836
 837         return -1;
 838 }
 839
 840
 841 static int has_attribute(const char *attrs, const char *attr) {
 842         int len;
 843         if (!attrs)
 844                 return 0;
 845
 846         len = strlen(attr);
 847         for (;;) {
 848                 const char *space = strchrnul(attrs, ' ');
 849                 if (len == space - attrs && !strncmp(attrs, attr, len))
 850                         return 1;
 851                 if (!*space)
 852                         return 0;
 853                 attrs = space + 1;
 854         }
 855 }
 856
 857 static struct ref *get_refs_list(struct transport *transport, int for_push)
 858 {
 859         struct helper_data *data = transport->data;
 860         struct child_process *helper;
 861         struct ref *ret = NULL;
 862         struct ref **tail = &ret;
 863         struct ref *posn;
 864         struct strbuf buf = STRBUF_INIT;
 865
 866         helper = get_helper(transport);
 867
 868         if (process_connect(transport, for_push)) {
 869                 do_take_over(transport);
 870                 return transport->get_refs_list(transport, for_push);
 871         }
 872
 873         if (data->push && for_push)
 874                 write_str_in_full(helper->in, "list for-push\n");
 875         else
 876                 write_str_in_full(helper->in, "list\n");
 877
 878         while (1) {
 879                 char *eov, *eon;
 880                 recvline(data, &buf);
 881
 882                 if (!*buf.buf)
 883                         break;
 884
 885                 eov = strchr(buf.buf, ' ');
 886                 if (!eov)
 887                         die("Malformed response in ref list: %s", buf.buf);
 888                 eon = strchr(eov + 1, ' ');
 889                 *eov = '\0';
 890                 if (eon)
 891                         *eon = '\0';
 892                 *tail = alloc_ref(eov + 1);
 893                 if (buf.buf[0] == '@')
 894                         (*tail)->symref = xstrdup(buf.buf + 1);
 895                 else if (buf.buf[0] != '?')
 896                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 897                 if (eon) {
 898                         if (has_attribute(eon + 1, "unchanged")) {
 899                                 (*tail)->status |= REF_STATUS_UPTODATE;
 900                                 read_ref((*tail)->name, (*tail)->old_sha1);
 901                         }
 902                 }
 903                 tail = &((*tail)->next);
 904         }
 905         if (debug)
 906                 fprintf(stderr, "Debug: Read ref listing.\n");
 907         strbuf_release(&buf);
 908
 909         for (posn = ret; posn; posn = posn->next)
 910                 resolve_remote_symref(posn, ret);
 911
 912         return ret;
 913 }
 914
 915 int transport_helper_init(struct transport *transport, const char *name)
 916 {
 917         struct helper_data *data = xcalloc(sizeof(*data), 1);
 918         data->name = name;
 919
 920         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 921                 debug = 1;
 922
 923         transport->data = data;
 924         transport->set_option = set_helper_option;
 925         transport->get_refs_list = get_refs_list;
 926         transport->fetch = fetch;
 927         transport->push_refs = push_refs;
 928         transport->disconnect = release_helper;
 929         transport->connect = connect_helper;
 930         transport->smart_options = &(data->transport_options);
 931         return 0;
 932 }
 933
 934 /*
 935  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 936  * buffer less), so attempt reads and writes with up to that size.
 937  */
 938 #define BUFFERSIZE 65536
 939 /* This should be enough to hold debugging message. */
 940 #define PBUFFERSIZE 8192
 941
 942 /* Print bidirectional transfer loop debug message. */
 943 static void transfer_debug(const char *fmt, ...)
 944 {
 945         va_list args;
 946         char msgbuf[PBUFFERSIZE];
 947         static int debug_enabled = -1;
 948
 949         if (debug_enabled < 0)
 950                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 951         if (!debug_enabled)
 952                 return;
 953
 954         va_start(args, fmt);
 955         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 956         va_end(args);
 957         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 958 }
 959
 960 /* Stream state: More data may be coming in this direction. */
 961 #define SSTATE_TRANSFERING 0
 962 /*
 963  * Stream state: No more data coming in this direction, flushing rest of
 964  * data.
 965  */
 966 #define SSTATE_FLUSHING 1
 967 /* Stream state: Transfer in this direction finished. */
 968 #define SSTATE_FINISHED 2
 969
 970 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 971 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 972 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 973
 974 /* Unidirectional transfer. */
 975 struct unidirectional_transfer {
 976         /* Source */
 977         int src;
 978         /* Destination */
 979         int dest;
 980         /* Is source socket? */
 981         int src_is_sock;
 982         /* Is destination socket? */
 983         int dest_is_sock;
 984         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 985         int state;
 986         /* Buffer. */
 987         char buf[BUFFERSIZE];
 988         /* Buffer used. */
 989         size_t bufuse;
 990         /* Name of source. */
 991         const char *src_name;
 992         /* Name of destination. */
 993         const char *dest_name;
 994 };
 995
 996 /* Closes the target (for writing) if transfer has finished. */
 997 static void udt_close_if_finished(struct unidirectional_transfer *t)
 998 {
 999         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1000                 t->state = SSTATE_FINISHED;
1001                 if (t->dest_is_sock)
1002                         shutdown(t->dest, SHUT_WR);
1003                 else
1004                         close(t->dest);
1005                 transfer_debug("Closed %s.", t->dest_name);
1006         }
1007 }
1008
1009 /*
1010  * Tries to read read data from source into buffer. If buffer is full,
1011  * no data is read. Returns 0 on success, -1 on error.
1012  */
1013 static int udt_do_read(struct unidirectional_transfer *t)
1014 {
1015         ssize_t bytes;
1016
1017         if (t->bufuse == BUFFERSIZE)
1018                 return 0;       /* No space for more. */
1019
1020         transfer_debug("%s is readable", t->src_name);
1021         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1022         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1023                 errno != EINTR) {
1024                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1025                 return -1;
1026         } else if (bytes == 0) {
1027                 transfer_debug("%s EOF (with %i bytes in buffer)",
1028                         t->src_name, t->bufuse);
1029                 t->state = SSTATE_FLUSHING;
1030         } else if (bytes > 0) {
1031                 t->bufuse += bytes;
1032                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1033                         (int)bytes, t->src_name, (int)t->bufuse);
1034         }
1035         return 0;
1036 }
1037
1038 /* Tries to write data from buffer into destination. If buffer is empty,
1039  * no data is written. Returns 0 on success, -1 on error.
1040  */
1041 static int udt_do_write(struct unidirectional_transfer *t)
1042 {
1043         ssize_t bytes;
1044
1045         if (t->bufuse == 0)
1046                 return 0;       /* Nothing to write. */
1047
1048         transfer_debug("%s is writable", t->dest_name);
1049         bytes = write(t->dest, t->buf, t->bufuse);
1050         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1051                 errno != EINTR) {
1052                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1053                 return -1;
1054         } else if (bytes > 0) {
1055                 t->bufuse -= bytes;
1056                 if (t->bufuse)
1057                         memmove(t->buf, t->buf + bytes, t->bufuse);
1058                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1059                         (int)bytes, t->dest_name, (int)t->bufuse);
1060         }
1061         return 0;
1062 }
1063
1064
1065 /* State of bidirectional transfer loop. */
1066 struct bidirectional_transfer_state {
1067         /* Direction from program to git. */
1068         struct unidirectional_transfer ptg;
1069         /* Direction from git to program. */
1070         struct unidirectional_transfer gtp;
1071 };
1072
1073 static void *udt_copy_task_routine(void *udt)
1074 {
1075         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1076         while (t->state != SSTATE_FINISHED) {
1077                 if (STATE_NEEDS_READING(t->state))
1078                         if (udt_do_read(t))
1079                                 return NULL;
1080                 if (STATE_NEEDS_WRITING(t->state))
1081                         if (udt_do_write(t))
1082                                 return NULL;
1083                 if (STATE_NEEDS_CLOSING(t->state))
1084                         udt_close_if_finished(t);
1085         }
1086         return udt;     /* Just some non-NULL value. */
1087 }
1088
1089 #ifndef NO_PTHREADS
1090
1091 /*
1092  * Join thread, with apporiate errors on failure. Name is name for the
1093  * thread (for error messages). Returns 0 on success, 1 on failure.
1094  */
1095 static int tloop_join(pthread_t thread, const char *name)
1096 {
1097         int err;
1098         void *tret;
1099         err = pthread_join(thread, &tret);
1100         if (!tret) {
1101                 error("%s thread failed", name);
1102                 return 1;
1103         }
1104         if (err) {
1105                 error("%s thread failed to join: %s", name, strerror(err));
1106                 return 1;
1107         }
1108         return 0;
1109 }
1110
1111 /*
1112  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1113  * -1 on failure.
1114  */
1115 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1116 {
1117         pthread_t gtp_thread;
1118         pthread_t ptg_thread;
1119         int err;
1120         int ret = 0;
1121         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1122                 &s->gtp);
1123         if (err)
1124                 die("Can't start thread for copying data: %s", strerror(err));
1125         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1126                 &s->ptg);
1127         if (err)
1128                 die("Can't start thread for copying data: %s", strerror(err));
1129
1130         ret |= tloop_join(gtp_thread, "Git to program copy");
1131         ret |= tloop_join(ptg_thread, "Program to git copy");
1132         return ret;
1133 }
1134 #else
1135
1136 /* Close the source and target (for writing) for transfer. */
1137 static void udt_kill_transfer(struct unidirectional_transfer *t)
1138 {
1139         t->state = SSTATE_FINISHED;
1140         /*
1141          * Socket read end left open isn't a disaster if nobody
1142          * attempts to read from it (mingw compat headers do not
1143          * have SHUT_RD)...
1144          *
1145          * We can't fully close the socket since otherwise gtp
1146          * task would first close the socket it sends data to
1147          * while closing the ptg file descriptors.
1148          */
1149         if (!t->src_is_sock)
1150                 close(t->src);
1151         if (t->dest_is_sock)
1152                 shutdown(t->dest, SHUT_WR);
1153         else
1154                 close(t->dest);
1155 }
1156
1157 /*
1158  * Join process, with apporiate errors on failure. Name is name for the
1159  * process (for error messages). Returns 0 on success, 1 on failure.
1160  */
1161 static int tloop_join(pid_t pid, const char *name)
1162 {
1163         int tret;
1164         if (waitpid(pid, &tret, 0) < 0) {
1165                 error("%s process failed to wait: %s", name, strerror(errno));
1166                 return 1;
1167         }
1168         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1169                 error("%s process failed", name);
1170                 return 1;
1171         }
1172         return 0;
1173 }
1174
1175 /*
1176  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1177  * -1 on failure.
1178  */
1179 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1180 {
1181         pid_t pid1, pid2;
1182         int ret = 0;
1183
1184         /* Fork thread #1: git to program. */
1185         pid1 = fork();
1186         if (pid1 < 0)
1187                 die_errno("Can't start thread for copying data");
1188         else if (pid1 == 0) {
1189                 udt_kill_transfer(&s->ptg);
1190                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1191         }
1192
1193         /* Fork thread #2: program to git. */
1194         pid2 = fork();
1195         if (pid2 < 0)
1196                 die_errno("Can't start thread for copying data");
1197         else if (pid2 == 0) {
1198                 udt_kill_transfer(&s->gtp);
1199                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1200         }
1201
1202         /*
1203          * Close both streams in parent as to not interfere with
1204          * end of file detection and wait for both tasks to finish.
1205          */
1206         udt_kill_transfer(&s->gtp);
1207         udt_kill_transfer(&s->ptg);
1208         ret |= tloop_join(pid1, "Git to program copy");
1209         ret |= tloop_join(pid2, "Program to git copy");
1210         return ret;
1211 }
1212 #endif
1213
1214 /*
1215  * Copies data from stdin to output and from input to stdout simultaneously.
1216  * Additionally filtering through given filter. If filter is NULL, uses
1217  * identity filter.
1218  */
1219 int bidirectional_transfer_loop(int input, int output)
1220 {
1221         struct bidirectional_transfer_state state;
1222
1223         /* Fill the state fields. */
1224         state.ptg.src = input;
1225         state.ptg.dest = 1;
1226         state.ptg.src_is_sock = (input == output);
1227         state.ptg.dest_is_sock = 0;
1228         state.ptg.state = SSTATE_TRANSFERING;
1229         state.ptg.bufuse = 0;
1230         state.ptg.src_name = "remote input";
1231         state.ptg.dest_name = "stdout";
1232
1233         state.gtp.src = 0;
1234         state.gtp.dest = output;
1235         state.gtp.src_is_sock = 0;
1236         state.gtp.dest_is_sock = (input == output);
1237         state.gtp.state = SSTATE_TRANSFERING;
1238         state.gtp.bufuse = 0;
1239         state.gtp.src_name = "stdin";
1240         state.gtp.dest_name = "remote output";
1241
1242         return tloop_spawnwait_tasks(&state);
1243 }