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 "remote.h"
   9 #include "string-list.h"
  10 #include "thread-utils.h"
  11 #include "sigchain.h"
  12 #include "argv-array.h"
  13 #include "refs.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                 signed_tags : 1,
  29                 check_connectivity : 1,
  30                 no_disconnect_req : 1,
  31                 no_private_update : 1;
  32         char *export_marks;
  33         char *import_marks;
  34         /* These go from remote name (as in "list") to private name */
  35         struct refspec *refspecs;
  36         int refspec_nr;
  37         /* Transport options for fetch-pack/send-pack (should one of
  38          * those be invoked).
  39          */
  40         struct git_transport_options transport_options;
  41 };
  42
  43 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  44 {
  45         if (debug)
  46                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  47         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  48                 != buffer->len)
  49                 die_errno("Full write to remote helper failed");
  50 }
  51
  52 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  53 {
  54         strbuf_reset(buffer);
  55         if (debug)
  56                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  57         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  58                 if (debug)
  59                         fprintf(stderr, "Debug: Remote helper quit.\n");
  60                 return 1;
  61         }
  62
  63         if (debug)
  64                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  65         return 0;
  66 }
  67
  68 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  69 {
  70         return recvline_fh(helper->out, buffer, helper->name);
  71 }
  72
  73 static void write_constant(int fd, const char *str)
  74 {
  75         if (debug)
  76                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  77         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  78                 die_errno("Full write to remote helper failed");
  79 }
  80
  81 static const char *remove_ext_force(const char *url)
  82 {
  83         if (url) {
  84                 const char *colon = strchr(url, ':');
  85                 if (colon && colon[1] == ':')
  86                         return colon + 2;
  87         }
  88         return url;
  89 }
  90
  91 static void do_take_over(struct transport *transport)
  92 {
  93         struct helper_data *data;
  94         data = (struct helper_data *)transport->data;
  95         transport_take_over(transport, data->helper);
  96         fclose(data->out);
  97         free(data);
  98 }
  99
 100 static void standard_options(struct transport *t);
 101
 102 static struct child_process *get_helper(struct transport *transport)
 103 {
 104         struct helper_data *data = transport->data;
 105         struct strbuf buf = STRBUF_INIT;
 106         struct child_process *helper;
 107         const char **refspecs = NULL;
 108         int refspec_nr = 0;
 109         int refspec_alloc = 0;
 110         int duped;
 111         int code;
 112
 113         if (data->helper)
 114                 return data->helper;
 115
 116         helper = xmalloc(sizeof(*helper));
 117         child_process_init(helper);
 118         helper->in = -1;
 119         helper->out = -1;
 120         helper->err = 0;
 121         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 122         argv_array_push(&helper->args, transport->remote->name);
 123         argv_array_push(&helper->args, remove_ext_force(transport->url));
 124         helper->git_cmd = 0;
 125         helper->silent_exec_failure = 1;
 126
 127         argv_array_pushf(&helper->env_array, "%s=%s", GIT_DIR_ENVIRONMENT,
 128                          get_git_dir());
 129
 130         code = start_command(helper);
 131         if (code < 0 && errno == ENOENT)
 132                 die("Unable to find remote helper for '%s'", data->name);
 133         else if (code != 0)
 134                 exit(code);
 135
 136         data->helper = helper;
 137         data->no_disconnect_req = 0;
 138
 139         /*
 140          * Open the output as FILE* so strbuf_getline() can be used.
 141          * Do this with duped fd because fclose() will close the fd,
 142          * and stuff like taking over will require the fd to remain.
 143          */
 144         duped = dup(helper->out);
 145         if (duped < 0)
 146                 die_errno("Can't dup helper output fd");
 147         data->out = xfdopen(duped, "r");
 148
 149         write_constant(helper->in, "capabilities\n");
 150
 151         while (1) {
 152                 const char *capname, *arg;
 153                 int mandatory = 0;
 154                 if (recvline(data, &buf))
 155                         exit(128);
 156
 157                 if (!*buf.buf)
 158                         break;
 159
 160                 if (*buf.buf == '*') {
 161                         capname = buf.buf + 1;
 162                         mandatory = 1;
 163                 } else
 164                         capname = buf.buf;
 165
 166                 if (debug)
 167                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 168                 if (!strcmp(capname, "fetch"))
 169                         data->fetch = 1;
 170                 else if (!strcmp(capname, "option"))
 171                         data->option = 1;
 172                 else if (!strcmp(capname, "push"))
 173                         data->push = 1;
 174                 else if (!strcmp(capname, "import"))
 175                         data->import = 1;
 176                 else if (!strcmp(capname, "bidi-import"))
 177                         data->bidi_import = 1;
 178                 else if (!strcmp(capname, "export"))
 179                         data->export = 1;
 180                 else if (!strcmp(capname, "check-connectivity"))
 181                         data->check_connectivity = 1;
 182                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 183                         ALLOC_GROW(refspecs,
 184                                    refspec_nr + 1,
 185                                    refspec_alloc);
 186                         refspecs[refspec_nr++] = xstrdup(arg);
 187                 } else if (!strcmp(capname, "connect")) {
 188                         data->connect = 1;
 189                 } else if (!strcmp(capname, "signed-tags")) {
 190                         data->signed_tags = 1;
 191                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 192                         data->export_marks = xstrdup(arg);
 193                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 194                         data->import_marks = xstrdup(arg);
 195                 } else if (starts_with(capname, "no-private-update")) {
 196                         data->no_private_update = 1;
 197                 } else if (mandatory) {
 198                         die("Unknown mandatory capability %s. This remote "
 199                             "helper probably needs newer version of Git.",
 200                             capname);
 201                 }
 202         }
 203         if (refspecs) {
 204                 int i;
 205                 data->refspec_nr = refspec_nr;
 206                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 207                 for (i = 0; i < refspec_nr; i++)
 208                         free((char *)refspecs[i]);
 209                 free(refspecs);
 210         } else if (data->import || data->bidi_import || data->export) {
 211                 warning("This remote helper should implement refspec capability.");
 212         }
 213         strbuf_release(&buf);
 214         if (debug)
 215                 fprintf(stderr, "Debug: Capabilities complete.\n");
 216         standard_options(transport);
 217         return data->helper;
 218 }
 219
 220 static int disconnect_helper(struct transport *transport)
 221 {
 222         struct helper_data *data = transport->data;
 223         int res = 0;
 224
 225         if (data->helper) {
 226                 if (debug)
 227                         fprintf(stderr, "Debug: Disconnecting.\n");
 228                 if (!data->no_disconnect_req) {
 229                         /*
 230                          * Ignore write errors; there's nothing we can do,
 231                          * since we're about to close the pipe anyway. And the
 232                          * most likely error is EPIPE due to the helper dying
 233                          * to report an error itself.
 234                          */
 235                         sigchain_push(SIGPIPE, SIG_IGN);
 236                         xwrite(data->helper->in, "\n", 1);
 237                         sigchain_pop(SIGPIPE);
 238                 }
 239                 close(data->helper->in);
 240                 close(data->helper->out);
 241                 fclose(data->out);
 242                 res = finish_command(data->helper);
 243                 free(data->helper);
 244                 data->helper = NULL;
 245         }
 246         return res;
 247 }
 248
 249 static const char *unsupported_options[] = {
 250         TRANS_OPT_UPLOADPACK,
 251         TRANS_OPT_RECEIVEPACK,
 252         TRANS_OPT_THIN,
 253         TRANS_OPT_KEEP
 254         };
 255
 256 static const char *boolean_options[] = {
 257         TRANS_OPT_THIN,
 258         TRANS_OPT_KEEP,
 259         TRANS_OPT_FOLLOWTAGS,
 260         TRANS_OPT_PUSH_CERT
 261         };
 262
 263 static int set_helper_option(struct transport *transport,
 264                           const char *name, const char *value)
 265 {
 266         struct helper_data *data = transport->data;
 267         struct strbuf buf = STRBUF_INIT;
 268         int i, ret, is_bool = 0;
 269
 270         get_helper(transport);
 271
 272         if (!data->option)
 273                 return 1;
 274
 275         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 276                 if (!strcmp(name, unsupported_options[i]))
 277                         return 1;
 278         }
 279
 280         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 281                 if (!strcmp(name, boolean_options[i])) {
 282                         is_bool = 1;
 283                         break;
 284                 }
 285         }
 286
 287         strbuf_addf(&buf, "option %s ", name);
 288         if (is_bool)
 289                 strbuf_addstr(&buf, value ? "true" : "false");
 290         else
 291                 quote_c_style(value, &buf, NULL, 0);
 292         strbuf_addch(&buf, '\n');
 293
 294         sendline(data, &buf);
 295         if (recvline(data, &buf))
 296                 exit(128);
 297
 298         if (!strcmp(buf.buf, "ok"))
 299                 ret = 0;
 300         else if (starts_with(buf.buf, "error")) {
 301                 ret = -1;
 302         } else if (!strcmp(buf.buf, "unsupported"))
 303                 ret = 1;
 304         else {
 305                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 306                 ret = 1;
 307         }
 308         strbuf_release(&buf);
 309         return ret;
 310 }
 311
 312 static void standard_options(struct transport *t)
 313 {
 314         char buf[16];
 315         int n;
 316         int v = t->verbose;
 317
 318         set_helper_option(t, "progress", t->progress ? "true" : "false");
 319
 320         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 321         if (n >= sizeof(buf))
 322                 die("impossibly large verbosity value");
 323         set_helper_option(t, "verbosity", buf);
 324 }
 325
 326 static int release_helper(struct transport *transport)
 327 {
 328         int res = 0;
 329         struct helper_data *data = transport->data;
 330         free_refspec(data->refspec_nr, data->refspecs);
 331         data->refspecs = NULL;
 332         res = disconnect_helper(transport);
 333         free(transport->data);
 334         return res;
 335 }
 336
 337 static int fetch_with_fetch(struct transport *transport,
 338                             int nr_heads, struct ref **to_fetch)
 339 {
 340         struct helper_data *data = transport->data;
 341         int i;
 342         struct strbuf buf = STRBUF_INIT;
 343
 344         for (i = 0; i < nr_heads; i++) {
 345                 const struct ref *posn = to_fetch[i];
 346                 if (posn->status & REF_STATUS_UPTODATE)
 347                         continue;
 348
 349                 strbuf_addf(&buf, "fetch %s %s\n",
 350                             sha1_to_hex(posn->old_sha1),
 351                             posn->symref ? posn->symref : posn->name);
 352         }
 353
 354         strbuf_addch(&buf, '\n');
 355         sendline(data, &buf);
 356
 357         while (1) {
 358                 if (recvline(data, &buf))
 359                         exit(128);
 360
 361                 if (starts_with(buf.buf, "lock ")) {
 362                         const char *name = buf.buf + 5;
 363                         if (transport->pack_lockfile)
 364                                 warning("%s also locked %s", data->name, name);
 365                         else
 366                                 transport->pack_lockfile = xstrdup(name);
 367                 }
 368                 else if (data->check_connectivity &&
 369                          data->transport_options.check_self_contained_and_connected &&
 370                          !strcmp(buf.buf, "connectivity-ok"))
 371                         data->transport_options.self_contained_and_connected = 1;
 372                 else if (!buf.len)
 373                         break;
 374                 else
 375                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 376         }
 377         strbuf_release(&buf);
 378         return 0;
 379 }
 380
 381 static int get_importer(struct transport *transport, struct child_process *fastimport)
 382 {
 383         struct child_process *helper = get_helper(transport);
 384         struct helper_data *data = transport->data;
 385         int cat_blob_fd, code;
 386         child_process_init(fastimport);
 387         fastimport->in = helper->out;
 388         argv_array_push(&fastimport->args, "fast-import");
 389         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 390
 391         if (data->bidi_import) {
 392                 cat_blob_fd = xdup(helper->in);
 393                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 394         }
 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 i;
 408
 409         child_process_init(fastexport);
 410
 411         /* we need to duplicate helper->in because we want to use it after
 412          * fastexport is done with it. */
 413         fastexport->out = dup(helper->in);
 414         argv_array_push(&fastexport->args, "fast-export");
 415         argv_array_push(&fastexport->args, "--use-done-feature");
 416         argv_array_push(&fastexport->args, data->signed_tags ?
 417                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 418         if (data->export_marks)
 419                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 420         if (data->import_marks)
 421                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 422
 423         for (i = 0; i < revlist_args->nr; i++)
 424                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 425
 426         fastexport->git_cmd = 1;
 427         return start_command(fastexport);
 428 }
 429
 430 static int fetch_with_import(struct transport *transport,
 431                              int nr_heads, struct ref **to_fetch)
 432 {
 433         struct child_process fastimport;
 434         struct helper_data *data = transport->data;
 435         int i;
 436         struct ref *posn;
 437         struct strbuf buf = STRBUF_INIT;
 438
 439         get_helper(transport);
 440
 441         if (get_importer(transport, &fastimport))
 442                 die("Couldn't run fast-import");
 443
 444         for (i = 0; i < nr_heads; i++) {
 445                 posn = to_fetch[i];
 446                 if (posn->status & REF_STATUS_UPTODATE)
 447                         continue;
 448
 449                 strbuf_addf(&buf, "import %s\n",
 450                             posn->symref ? posn->symref : posn->name);
 451                 sendline(data, &buf);
 452                 strbuf_reset(&buf);
 453         }
 454
 455         write_constant(data->helper->in, "\n");
 456         /*
 457          * remote-helpers that advertise the bidi-import capability are required to
 458          * buffer the complete batch of import commands until this newline before
 459          * sending data to fast-import.
 460          * These helpers read back data from fast-import on their stdin, which could
 461          * be mixed with import commands, otherwise.
 462          */
 463
 464         if (finish_command(&fastimport))
 465                 die("Error while running fast-import");
 466
 467         /*
 468          * The fast-import stream of a remote helper that advertises
 469          * the "refspec" capability writes to the refs named after the
 470          * right hand side of the first refspec matching each ref we
 471          * were fetching.
 472          *
 473          * (If no "refspec" capability was specified, for historical
 474          * reasons we default to the equivalent of *:*.)
 475          *
 476          * Store the result in to_fetch[i].old_sha1.  Callers such
 477          * as "git fetch" can use the value to write feedback to the
 478          * terminal, populate FETCH_HEAD, and determine what new value
 479          * should be written to peer_ref if the update is a
 480          * fast-forward or this is a forced update.
 481          */
 482         for (i = 0; i < nr_heads; i++) {
 483                 char *private, *name;
 484                 posn = to_fetch[i];
 485                 if (posn->status & REF_STATUS_UPTODATE)
 486                         continue;
 487                 name = posn->symref ? posn->symref : posn->name;
 488                 if (data->refspecs)
 489                         private = apply_refspecs(data->refspecs, data->refspec_nr, name);
 490                 else
 491                         private = xstrdup(name);
 492                 if (private) {
 493                         if (read_ref(private, posn->old_sha1) < 0)
 494                                 die("Could not read ref %s", private);
 495                         free(private);
 496                 }
 497         }
 498         strbuf_release(&buf);
 499         return 0;
 500 }
 501
 502 static int process_connect_service(struct transport *transport,
 503                                    const char *name, const char *exec)
 504 {
 505         struct helper_data *data = transport->data;
 506         struct strbuf cmdbuf = STRBUF_INIT;
 507         struct child_process *helper;
 508         int r, duped, ret = 0;
 509         FILE *input;
 510
 511         helper = get_helper(transport);
 512
 513         /*
 514          * Yes, dup the pipe another time, as we need unbuffered version
 515          * of input pipe as FILE*. fclose() closes the underlying fd and
 516          * stream buffering only can be changed before first I/O operation
 517          * on it.
 518          */
 519         duped = dup(helper->out);
 520         if (duped < 0)
 521                 die_errno("Can't dup helper output fd");
 522         input = xfdopen(duped, "r");
 523         setvbuf(input, NULL, _IONBF, 0);
 524
 525         /*
 526          * Handle --upload-pack and friends. This is fire and forget...
 527          * just warn if it fails.
 528          */
 529         if (strcmp(name, exec)) {
 530                 r = set_helper_option(transport, "servpath", exec);
 531                 if (r > 0)
 532                         warning("Setting remote service path not supported by protocol.");
 533                 else if (r < 0)
 534                         warning("Invalid remote service path.");
 535         }
 536
 537         if (data->connect)
 538                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 539         else
 540                 goto exit;
 541
 542         sendline(data, &cmdbuf);
 543         if (recvline_fh(input, &cmdbuf, name))
 544                 exit(128);
 545
 546         if (!strcmp(cmdbuf.buf, "")) {
 547                 data->no_disconnect_req = 1;
 548                 if (debug)
 549                         fprintf(stderr, "Debug: Smart transport connection "
 550                                 "ready.\n");
 551                 ret = 1;
 552         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 553                 if (debug)
 554                         fprintf(stderr, "Debug: Falling back to dumb "
 555                                 "transport.\n");
 556         } else
 557                 die("Unknown response to connect: %s",
 558                         cmdbuf.buf);
 559
 560 exit:
 561         fclose(input);
 562         return ret;
 563 }
 564
 565 static int process_connect(struct transport *transport,
 566                                      int for_push)
 567 {
 568         struct helper_data *data = transport->data;
 569         const char *name;
 570         const char *exec;
 571
 572         name = for_push ? "git-receive-pack" : "git-upload-pack";
 573         if (for_push)
 574                 exec = data->transport_options.receivepack;
 575         else
 576                 exec = data->transport_options.uploadpack;
 577
 578         return process_connect_service(transport, name, exec);
 579 }
 580
 581 static int connect_helper(struct transport *transport, const char *name,
 582                    const char *exec, int fd[2])
 583 {
 584         struct helper_data *data = transport->data;
 585
 586         /* Get_helper so connect is inited. */
 587         get_helper(transport);
 588         if (!data->connect)
 589                 die("Operation not supported by protocol.");
 590
 591         if (!process_connect_service(transport, name, exec))
 592                 die("Can't connect to subservice %s.", name);
 593
 594         fd[0] = data->helper->out;
 595         fd[1] = data->helper->in;
 596         return 0;
 597 }
 598
 599 static int fetch(struct transport *transport,
 600                  int nr_heads, struct ref **to_fetch)
 601 {
 602         struct helper_data *data = transport->data;
 603         int i, count;
 604
 605         if (process_connect(transport, 0)) {
 606                 do_take_over(transport);
 607                 return transport->fetch(transport, nr_heads, to_fetch);
 608         }
 609
 610         count = 0;
 611         for (i = 0; i < nr_heads; i++)
 612                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 613                         count++;
 614
 615         if (!count)
 616                 return 0;
 617
 618         if (data->check_connectivity &&
 619             data->transport_options.check_self_contained_and_connected)
 620                 set_helper_option(transport, "check-connectivity", "true");
 621
 622         if (transport->cloning)
 623                 set_helper_option(transport, "cloning", "true");
 624
 625         if (data->transport_options.update_shallow)
 626                 set_helper_option(transport, "update-shallow", "true");
 627
 628         if (data->fetch)
 629                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 630
 631         if (data->import)
 632                 return fetch_with_import(transport, nr_heads, to_fetch);
 633
 634         return -1;
 635 }
 636
 637 static int push_update_ref_status(struct strbuf *buf,
 638                                    struct ref **ref,
 639                                    struct ref *remote_refs)
 640 {
 641         char *refname, *msg;
 642         int status, forced = 0;
 643
 644         if (starts_with(buf->buf, "ok ")) {
 645                 status = REF_STATUS_OK;
 646                 refname = buf->buf + 3;
 647         } else if (starts_with(buf->buf, "error ")) {
 648                 status = REF_STATUS_REMOTE_REJECT;
 649                 refname = buf->buf + 6;
 650         } else
 651                 die("expected ok/error, helper said '%s'", buf->buf);
 652
 653         msg = strchr(refname, ' ');
 654         if (msg) {
 655                 struct strbuf msg_buf = STRBUF_INIT;
 656                 const char *end;
 657
 658                 *msg++ = '\0';
 659                 if (!unquote_c_style(&msg_buf, msg, &end))
 660                         msg = strbuf_detach(&msg_buf, NULL);
 661                 else
 662                         msg = xstrdup(msg);
 663                 strbuf_release(&msg_buf);
 664
 665                 if (!strcmp(msg, "no match")) {
 666                         status = REF_STATUS_NONE;
 667                         free(msg);
 668                         msg = NULL;
 669                 }
 670                 else if (!strcmp(msg, "up to date")) {
 671                         status = REF_STATUS_UPTODATE;
 672                         free(msg);
 673                         msg = NULL;
 674                 }
 675                 else if (!strcmp(msg, "non-fast forward")) {
 676                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 677                         free(msg);
 678                         msg = NULL;
 679                 }
 680                 else if (!strcmp(msg, "already exists")) {
 681                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 682                         free(msg);
 683                         msg = NULL;
 684                 }
 685                 else if (!strcmp(msg, "fetch first")) {
 686                         status = REF_STATUS_REJECT_FETCH_FIRST;
 687                         free(msg);
 688                         msg = NULL;
 689                 }
 690                 else if (!strcmp(msg, "needs force")) {
 691                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 692                         free(msg);
 693                         msg = NULL;
 694                 }
 695                 else if (!strcmp(msg, "stale info")) {
 696                         status = REF_STATUS_REJECT_STALE;
 697                         free(msg);
 698                         msg = NULL;
 699                 }
 700                 else if (!strcmp(msg, "forced update")) {
 701                         forced = 1;
 702                         free(msg);
 703                         msg = NULL;
 704                 }
 705         }
 706
 707         if (*ref)
 708                 *ref = find_ref_by_name(*ref, refname);
 709         if (!*ref)
 710                 *ref = find_ref_by_name(remote_refs, refname);
 711         if (!*ref) {
 712                 warning("helper reported unexpected status of %s", refname);
 713                 return 1;
 714         }
 715
 716         if ((*ref)->status != REF_STATUS_NONE) {
 717                 /*
 718                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 719                  * status reported by the remote helper if the latter is 'no match'.
 720                  */
 721                 if (status == REF_STATUS_NONE)
 722                         return 1;
 723         }
 724
 725         (*ref)->status = status;
 726         (*ref)->forced_update |= forced;
 727         (*ref)->remote_status = msg;
 728         return !(status == REF_STATUS_OK);
 729 }
 730
 731 static int push_update_refs_status(struct helper_data *data,
 732                                     struct ref *remote_refs,
 733                                     int flags)
 734 {
 735         struct strbuf buf = STRBUF_INIT;
 736         struct ref *ref = remote_refs;
 737         int ret = 0;
 738
 739         for (;;) {
 740                 char *private;
 741
 742                 if (recvline(data, &buf)) {
 743                         ret = 1;
 744                         break;
 745                 }
 746
 747                 if (!buf.len)
 748                         break;
 749
 750                 if (push_update_ref_status(&buf, &ref, remote_refs))
 751                         continue;
 752
 753                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 754                         continue;
 755
 756                 /* propagate back the update to the remote namespace */
 757                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 758                 if (!private)
 759                         continue;
 760                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 761                 free(private);
 762         }
 763         strbuf_release(&buf);
 764         return ret;
 765 }
 766
 767 static int push_refs_with_push(struct transport *transport,
 768                                struct ref *remote_refs, int flags)
 769 {
 770         int force_all = flags & TRANSPORT_PUSH_FORCE;
 771         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 772         struct helper_data *data = transport->data;
 773         struct strbuf buf = STRBUF_INIT;
 774         struct ref *ref;
 775         struct string_list cas_options = STRING_LIST_INIT_DUP;
 776         struct string_list_item *cas_option;
 777
 778         get_helper(transport);
 779         if (!data->push)
 780                 return 1;
 781
 782         for (ref = remote_refs; ref; ref = ref->next) {
 783                 if (!ref->peer_ref && !mirror)
 784                         continue;
 785
 786                 /* Check for statuses set by set_ref_status_for_push() */
 787                 switch (ref->status) {
 788                 case REF_STATUS_REJECT_NONFASTFORWARD:
 789                 case REF_STATUS_REJECT_STALE:
 790                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 791                 case REF_STATUS_UPTODATE:
 792                         continue;
 793                 default:
 794                         ; /* do nothing */
 795                 }
 796
 797                 if (force_all)
 798                         ref->force = 1;
 799
 800                 strbuf_addstr(&buf, "push ");
 801                 if (!ref->deletion) {
 802                         if (ref->force)
 803                                 strbuf_addch(&buf, '+');
 804                         if (ref->peer_ref)
 805                                 strbuf_addstr(&buf, ref->peer_ref->name);
 806                         else
 807                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 808                 }
 809                 strbuf_addch(&buf, ':');
 810                 strbuf_addstr(&buf, ref->name);
 811                 strbuf_addch(&buf, '\n');
 812
 813                 /*
 814                  * The "--force-with-lease" options without explicit
 815                  * values to expect have already been expanded into
 816                  * the ref->old_sha1_expect[] field; we can ignore
 817                  * transport->smart_options->cas altogether and instead
 818                  * can enumerate them from the refs.
 819                  */
 820                 if (ref->expect_old_sha1) {
 821                         struct strbuf cas = STRBUF_INIT;
 822                         strbuf_addf(&cas, "%s:%s",
 823                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 824                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 825                 }
 826         }
 827         if (buf.len == 0) {
 828                 string_list_clear(&cas_options, 0);
 829                 return 0;
 830         }
 831
 832         for_each_string_list_item(cas_option, &cas_options)
 833                 set_helper_option(transport, "cas", cas_option->string);
 834
 835         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 836                 if (set_helper_option(transport, "dry-run", "true") != 0)
 837                         die("helper %s does not support dry-run", data->name);
 838         } else if (flags & TRANSPORT_PUSH_CERT) {
 839                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 840                         die("helper %s does not support --signed", data->name);
 841         }
 842
 843         strbuf_addch(&buf, '\n');
 844         sendline(data, &buf);
 845         strbuf_release(&buf);
 846
 847         return push_update_refs_status(data, remote_refs, flags);
 848 }
 849
 850 static int push_refs_with_export(struct transport *transport,
 851                 struct ref *remote_refs, int flags)
 852 {
 853         struct ref *ref;
 854         struct child_process *helper, exporter;
 855         struct helper_data *data = transport->data;
 856         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 857         struct strbuf buf = STRBUF_INIT;
 858
 859         if (!data->refspecs)
 860                 die("remote-helper doesn't support push; refspec needed");
 861
 862         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 863                 if (set_helper_option(transport, "dry-run", "true") != 0)
 864                         die("helper %s does not support dry-run", data->name);
 865         } else if (flags & TRANSPORT_PUSH_CERT) {
 866                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 867                         die("helper %s does not support --signed", data->name);
 868         }
 869
 870         if (flags & TRANSPORT_PUSH_FORCE) {
 871                 if (set_helper_option(transport, "force", "true") != 0)
 872                         warning("helper %s does not support 'force'", data->name);
 873         }
 874
 875         helper = get_helper(transport);
 876
 877         write_constant(helper->in, "export\n");
 878
 879         for (ref = remote_refs; ref; ref = ref->next) {
 880                 char *private;
 881                 unsigned char sha1[20];
 882
 883                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 884                 if (private && !get_sha1(private, sha1)) {
 885                         strbuf_addf(&buf, "^%s", private);
 886                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 887                         hashcpy(ref->old_sha1, sha1);
 888                 }
 889                 free(private);
 890
 891                 if (ref->peer_ref) {
 892                         if (strcmp(ref->name, ref->peer_ref->name)) {
 893                                 if (!ref->deletion) {
 894                                         const char *name;
 895                                         int flag;
 896
 897                                         /* Follow symbolic refs (mainly for HEAD). */
 898                                         name = resolve_ref_unsafe(
 899                                                  ref->peer_ref->name,
 900                                                  RESOLVE_REF_READING,
 901                                                  sha1, &flag);
 902                                         if (!name || !(flag & REF_ISSYMREF))
 903                                                 name = ref->peer_ref->name;
 904
 905                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 906                                 } else
 907                                         strbuf_addf(&buf, ":%s", ref->name);
 908
 909                                 string_list_append(&revlist_args, "--refspec");
 910                                 string_list_append(&revlist_args, buf.buf);
 911                                 strbuf_release(&buf);
 912                         }
 913                         if (!ref->deletion)
 914                                 string_list_append(&revlist_args, ref->peer_ref->name);
 915                 }
 916         }
 917
 918         if (get_exporter(transport, &exporter, &revlist_args))
 919                 die("Couldn't run fast-export");
 920
 921         string_list_clear(&revlist_args, 1);
 922
 923         if (finish_command(&exporter))
 924                 die("Error while running fast-export");
 925         if (push_update_refs_status(data, remote_refs, flags))
 926                 return 1;
 927
 928         if (data->export_marks) {
 929                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 930                 rename(buf.buf, data->export_marks);
 931                 strbuf_release(&buf);
 932         }
 933
 934         return 0;
 935 }
 936
 937 static int push_refs(struct transport *transport,
 938                 struct ref *remote_refs, int flags)
 939 {
 940         struct helper_data *data = transport->data;
 941
 942         if (process_connect(transport, 1)) {
 943                 do_take_over(transport);
 944                 return transport->push_refs(transport, remote_refs, flags);
 945         }
 946
 947         if (!remote_refs) {
 948                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 949                         "Perhaps you should specify a branch such as 'master'.\n");
 950                 return 0;
 951         }
 952
 953         if (data->push)
 954                 return push_refs_with_push(transport, remote_refs, flags);
 955
 956         if (data->export)
 957                 return push_refs_with_export(transport, remote_refs, flags);
 958
 959         return -1;
 960 }
 961
 962
 963 static int has_attribute(const char *attrs, const char *attr) {
 964         int len;
 965         if (!attrs)
 966                 return 0;
 967
 968         len = strlen(attr);
 969         for (;;) {
 970                 const char *space = strchrnul(attrs, ' ');
 971                 if (len == space - attrs && !strncmp(attrs, attr, len))
 972                         return 1;
 973                 if (!*space)
 974                         return 0;
 975                 attrs = space + 1;
 976         }
 977 }
 978
 979 static struct ref *get_refs_list(struct transport *transport, int for_push)
 980 {
 981         struct helper_data *data = transport->data;
 982         struct child_process *helper;
 983         struct ref *ret = NULL;
 984         struct ref **tail = &ret;
 985         struct ref *posn;
 986         struct strbuf buf = STRBUF_INIT;
 987
 988         helper = get_helper(transport);
 989
 990         if (process_connect(transport, for_push)) {
 991                 do_take_over(transport);
 992                 return transport->get_refs_list(transport, for_push);
 993         }
 994
 995         if (data->push && for_push)
 996                 write_str_in_full(helper->in, "list for-push\n");
 997         else
 998                 write_str_in_full(helper->in, "list\n");
 999
1000         while (1) {
1001                 char *eov, *eon;
1002                 if (recvline(data, &buf))
1003                         exit(128);
1004
1005                 if (!*buf.buf)
1006                         break;
1007
1008                 eov = strchr(buf.buf, ' ');
1009                 if (!eov)
1010                         die("Malformed response in ref list: %s", buf.buf);
1011                 eon = strchr(eov + 1, ' ');
1012                 *eov = '\0';
1013                 if (eon)
1014                         *eon = '\0';
1015                 *tail = alloc_ref(eov + 1);
1016                 if (buf.buf[0] == '@')
1017                         (*tail)->symref = xstrdup(buf.buf + 1);
1018                 else if (buf.buf[0] != '?')
1019                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1020                 if (eon) {
1021                         if (has_attribute(eon + 1, "unchanged")) {
1022                                 (*tail)->status |= REF_STATUS_UPTODATE;
1023                                 if (read_ref((*tail)->name,
1024                                              (*tail)->old_sha1) < 0)
1025                                         die(N_("Could not read ref %s"),
1026                                             (*tail)->name);
1027                         }
1028                 }
1029                 tail = &((*tail)->next);
1030         }
1031         if (debug)
1032                 fprintf(stderr, "Debug: Read ref listing.\n");
1033         strbuf_release(&buf);
1034
1035         for (posn = ret; posn; posn = posn->next)
1036                 resolve_remote_symref(posn, ret);
1037
1038         return ret;
1039 }
1040
1041 int transport_helper_init(struct transport *transport, const char *name)
1042 {
1043         struct helper_data *data = xcalloc(1, sizeof(*data));
1044         data->name = name;
1045
1046         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1047                 debug = 1;
1048
1049         transport->data = data;
1050         transport->set_option = set_helper_option;
1051         transport->get_refs_list = get_refs_list;
1052         transport->fetch = fetch;
1053         transport->push_refs = push_refs;
1054         transport->disconnect = release_helper;
1055         transport->connect = connect_helper;
1056         transport->smart_options = &(data->transport_options);
1057         return 0;
1058 }
1059
1060 /*
1061  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1062  * buffer less), so attempt reads and writes with up to that size.
1063  */
1064 #define BUFFERSIZE 65536
1065 /* This should be enough to hold debugging message. */
1066 #define PBUFFERSIZE 8192
1067
1068 /* Print bidirectional transfer loop debug message. */
1069 __attribute__((format (printf, 1, 2)))
1070 static void transfer_debug(const char *fmt, ...)
1071 {
1072         va_list args;
1073         char msgbuf[PBUFFERSIZE];
1074         static int debug_enabled = -1;
1075
1076         if (debug_enabled < 0)
1077                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1078         if (!debug_enabled)
1079                 return;
1080
1081         va_start(args, fmt);
1082         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1083         va_end(args);
1084         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1085 }
1086
1087 /* Stream state: More data may be coming in this direction. */
1088 #define SSTATE_TRANSFERING 0
1089 /*
1090  * Stream state: No more data coming in this direction, flushing rest of
1091  * data.
1092  */
1093 #define SSTATE_FLUSHING 1
1094 /* Stream state: Transfer in this direction finished. */
1095 #define SSTATE_FINISHED 2
1096
1097 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1098 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1099 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1100
1101 /* Unidirectional transfer. */
1102 struct unidirectional_transfer {
1103         /* Source */
1104         int src;
1105         /* Destination */
1106         int dest;
1107         /* Is source socket? */
1108         int src_is_sock;
1109         /* Is destination socket? */
1110         int dest_is_sock;
1111         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1112         int state;
1113         /* Buffer. */
1114         char buf[BUFFERSIZE];
1115         /* Buffer used. */
1116         size_t bufuse;
1117         /* Name of source. */
1118         const char *src_name;
1119         /* Name of destination. */
1120         const char *dest_name;
1121 };
1122
1123 /* Closes the target (for writing) if transfer has finished. */
1124 static void udt_close_if_finished(struct unidirectional_transfer *t)
1125 {
1126         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1127                 t->state = SSTATE_FINISHED;
1128                 if (t->dest_is_sock)
1129                         shutdown(t->dest, SHUT_WR);
1130                 else
1131                         close(t->dest);
1132                 transfer_debug("Closed %s.", t->dest_name);
1133         }
1134 }
1135
1136 /*
1137  * Tries to read read data from source into buffer. If buffer is full,
1138  * no data is read. Returns 0 on success, -1 on error.
1139  */
1140 static int udt_do_read(struct unidirectional_transfer *t)
1141 {
1142         ssize_t bytes;
1143
1144         if (t->bufuse == BUFFERSIZE)
1145                 return 0;       /* No space for more. */
1146
1147         transfer_debug("%s is readable", t->src_name);
1148         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1149         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1150                 errno != EINTR) {
1151                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1152                 return -1;
1153         } else if (bytes == 0) {
1154                 transfer_debug("%s EOF (with %i bytes in buffer)",
1155                         t->src_name, (int)t->bufuse);
1156                 t->state = SSTATE_FLUSHING;
1157         } else if (bytes > 0) {
1158                 t->bufuse += bytes;
1159                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1160                         (int)bytes, t->src_name, (int)t->bufuse);
1161         }
1162         return 0;
1163 }
1164
1165 /* Tries to write data from buffer into destination. If buffer is empty,
1166  * no data is written. Returns 0 on success, -1 on error.
1167  */
1168 static int udt_do_write(struct unidirectional_transfer *t)
1169 {
1170         ssize_t bytes;
1171
1172         if (t->bufuse == 0)
1173                 return 0;       /* Nothing to write. */
1174
1175         transfer_debug("%s is writable", t->dest_name);
1176         bytes = xwrite(t->dest, t->buf, t->bufuse);
1177         if (bytes < 0 && errno != EWOULDBLOCK) {
1178                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1179                 return -1;
1180         } else if (bytes > 0) {
1181                 t->bufuse -= bytes;
1182                 if (t->bufuse)
1183                         memmove(t->buf, t->buf + bytes, t->bufuse);
1184                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1185                         (int)bytes, t->dest_name, (int)t->bufuse);
1186         }
1187         return 0;
1188 }
1189
1190
1191 /* State of bidirectional transfer loop. */
1192 struct bidirectional_transfer_state {
1193         /* Direction from program to git. */
1194         struct unidirectional_transfer ptg;
1195         /* Direction from git to program. */
1196         struct unidirectional_transfer gtp;
1197 };
1198
1199 static void *udt_copy_task_routine(void *udt)
1200 {
1201         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1202         while (t->state != SSTATE_FINISHED) {
1203                 if (STATE_NEEDS_READING(t->state))
1204                         if (udt_do_read(t))
1205                                 return NULL;
1206                 if (STATE_NEEDS_WRITING(t->state))
1207                         if (udt_do_write(t))
1208                                 return NULL;
1209                 if (STATE_NEEDS_CLOSING(t->state))
1210                         udt_close_if_finished(t);
1211         }
1212         return udt;     /* Just some non-NULL value. */
1213 }
1214
1215 #ifndef NO_PTHREADS
1216
1217 /*
1218  * Join thread, with appropriate errors on failure. Name is name for the
1219  * thread (for error messages). Returns 0 on success, 1 on failure.
1220  */
1221 static int tloop_join(pthread_t thread, const char *name)
1222 {
1223         int err;
1224         void *tret;
1225         err = pthread_join(thread, &tret);
1226         if (!tret) {
1227                 error("%s thread failed", name);
1228                 return 1;
1229         }
1230         if (err) {
1231                 error("%s thread failed to join: %s", name, strerror(err));
1232                 return 1;
1233         }
1234         return 0;
1235 }
1236
1237 /*
1238  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1239  * -1 on failure.
1240  */
1241 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1242 {
1243         pthread_t gtp_thread;
1244         pthread_t ptg_thread;
1245         int err;
1246         int ret = 0;
1247         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1248                 &s->gtp);
1249         if (err)
1250                 die("Can't start thread for copying data: %s", strerror(err));
1251         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1252                 &s->ptg);
1253         if (err)
1254                 die("Can't start thread for copying data: %s", strerror(err));
1255
1256         ret |= tloop_join(gtp_thread, "Git to program copy");
1257         ret |= tloop_join(ptg_thread, "Program to git copy");
1258         return ret;
1259 }
1260 #else
1261
1262 /* Close the source and target (for writing) for transfer. */
1263 static void udt_kill_transfer(struct unidirectional_transfer *t)
1264 {
1265         t->state = SSTATE_FINISHED;
1266         /*
1267          * Socket read end left open isn't a disaster if nobody
1268          * attempts to read from it (mingw compat headers do not
1269          * have SHUT_RD)...
1270          *
1271          * We can't fully close the socket since otherwise gtp
1272          * task would first close the socket it sends data to
1273          * while closing the ptg file descriptors.
1274          */
1275         if (!t->src_is_sock)
1276                 close(t->src);
1277         if (t->dest_is_sock)
1278                 shutdown(t->dest, SHUT_WR);
1279         else
1280                 close(t->dest);
1281 }
1282
1283 /*
1284  * Join process, with appropriate errors on failure. Name is name for the
1285  * process (for error messages). Returns 0 on success, 1 on failure.
1286  */
1287 static int tloop_join(pid_t pid, const char *name)
1288 {
1289         int tret;
1290         if (waitpid(pid, &tret, 0) < 0) {
1291                 error("%s process failed to wait: %s", name, strerror(errno));
1292                 return 1;
1293         }
1294         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1295                 error("%s process failed", name);
1296                 return 1;
1297         }
1298         return 0;
1299 }
1300
1301 /*
1302  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1303  * -1 on failure.
1304  */
1305 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1306 {
1307         pid_t pid1, pid2;
1308         int ret = 0;
1309
1310         /* Fork thread #1: git to program. */
1311         pid1 = fork();
1312         if (pid1 < 0)
1313                 die_errno("Can't start thread for copying data");
1314         else if (pid1 == 0) {
1315                 udt_kill_transfer(&s->ptg);
1316                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1317         }
1318
1319         /* Fork thread #2: program to git. */
1320         pid2 = fork();
1321         if (pid2 < 0)
1322                 die_errno("Can't start thread for copying data");
1323         else if (pid2 == 0) {
1324                 udt_kill_transfer(&s->gtp);
1325                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1326         }
1327
1328         /*
1329          * Close both streams in parent as to not interfere with
1330          * end of file detection and wait for both tasks to finish.
1331          */
1332         udt_kill_transfer(&s->gtp);
1333         udt_kill_transfer(&s->ptg);
1334         ret |= tloop_join(pid1, "Git to program copy");
1335         ret |= tloop_join(pid2, "Program to git copy");
1336         return ret;
1337 }
1338 #endif
1339
1340 /*
1341  * Copies data from stdin to output and from input to stdout simultaneously.
1342  * Additionally filtering through given filter. If filter is NULL, uses
1343  * identity filter.
1344  */
1345 int bidirectional_transfer_loop(int input, int output)
1346 {
1347         struct bidirectional_transfer_state state;
1348
1349         /* Fill the state fields. */
1350         state.ptg.src = input;
1351         state.ptg.dest = 1;
1352         state.ptg.src_is_sock = (input == output);
1353         state.ptg.dest_is_sock = 0;
1354         state.ptg.state = SSTATE_TRANSFERING;
1355         state.ptg.bufuse = 0;
1356         state.ptg.src_name = "remote input";
1357         state.ptg.dest_name = "stdout";
1358
1359         state.gtp.src = 0;
1360         state.gtp.dest = output;
1361         state.gtp.src_is_sock = 0;
1362         state.gtp.dest_is_sock = (input == output);
1363         state.gtp.state = SSTATE_TRANSFERING;
1364         state.gtp.bufuse = 0;
1365         state.gtp.src_name = "stdin";
1366         state.gtp.dest_name = "remote output";
1367
1368         return tloop_spawnwait_tasks(&state);
1369 }