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 #include "refs.h"
  15
  16 static int debug;
  17
  18 struct helper_data {
  19         const char *name;
  20         struct child_process *helper;
  21         FILE *out;
  22         unsigned fetch : 1,
  23                 import : 1,
  24                 bidi_import : 1,
  25                 export : 1,
  26                 option : 1,
  27                 push : 1,
  28                 connect : 1,
  29                 signed_tags : 1,
  30                 check_connectivity : 1,
  31                 no_disconnect_req : 1,
  32                 no_private_update : 1;
  33         char *export_marks;
  34         char *import_marks;
  35         /* These go from remote name (as in "list") to private name */
  36         struct refspec *refspecs;
  37         int refspec_nr;
  38         /* Transport options for fetch-pack/send-pack (should one of
  39          * those be invoked).
  40          */
  41         struct git_transport_options transport_options;
  42 };
  43
  44 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  45 {
  46         if (debug)
  47                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  48         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  49                 != buffer->len)
  50                 die_errno("Full write to remote helper failed");
  51 }
  52
  53 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  54 {
  55         strbuf_reset(buffer);
  56         if (debug)
  57                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  58         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  59                 if (debug)
  60                         fprintf(stderr, "Debug: Remote helper quit.\n");
  61                 return 1;
  62         }
  63
  64         if (debug)
  65                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  66         return 0;
  67 }
  68
  69 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  70 {
  71         return recvline_fh(helper->out, buffer, helper->name);
  72 }
  73
  74 static void write_constant(int fd, const char *str)
  75 {
  76         if (debug)
  77                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  78         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  79                 die_errno("Full write to remote helper failed");
  80 }
  81
  82 static const char *remove_ext_force(const char *url)
  83 {
  84         if (url) {
  85                 const char *colon = strchr(url, ':');
  86                 if (colon && colon[1] == ':')
  87                         return colon + 2;
  88         }
  89         return url;
  90 }
  91
  92 static void do_take_over(struct transport *transport)
  93 {
  94         struct helper_data *data;
  95         data = (struct helper_data *)transport->data;
  96         transport_take_over(transport, data->helper);
  97         fclose(data->out);
  98         free(data);
  99 }
 100
 101 static struct child_process *get_helper(struct transport *transport)
 102 {
 103         struct helper_data *data = transport->data;
 104         struct strbuf buf = STRBUF_INIT;
 105         struct child_process *helper;
 106         const char **refspecs = NULL;
 107         int refspec_nr = 0;
 108         int refspec_alloc = 0;
 109         int duped;
 110         int code;
 111         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 112         const char *helper_env[] = {
 113                 git_dir_buf,
 114                 NULL
 115         };
 116
 117
 118         if (data->helper)
 119                 return data->helper;
 120
 121         helper = xmalloc(sizeof(*helper));
 122         child_process_init(helper);
 123         helper->in = -1;
 124         helper->out = -1;
 125         helper->err = 0;
 126         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 127         argv_array_push(&helper->args, transport->remote->name);
 128         argv_array_push(&helper->args, remove_ext_force(transport->url));
 129         helper->git_cmd = 0;
 130         helper->silent_exec_failure = 1;
 131
 132         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 133         helper->env = helper_env;
 134
 135         code = start_command(helper);
 136         if (code < 0 && errno == ENOENT)
 137                 die("Unable to find remote helper for '%s'", data->name);
 138         else if (code != 0)
 139                 exit(code);
 140
 141         data->helper = helper;
 142         data->no_disconnect_req = 0;
 143
 144         /*
 145          * Open the output as FILE* so strbuf_getline() can be used.
 146          * Do this with duped fd because fclose() will close the fd,
 147          * and stuff like taking over will require the fd to remain.
 148          */
 149         duped = dup(helper->out);
 150         if (duped < 0)
 151                 die_errno("Can't dup helper output fd");
 152         data->out = xfdopen(duped, "r");
 153
 154         write_constant(helper->in, "capabilities\n");
 155
 156         while (1) {
 157                 const char *capname, *arg;
 158                 int mandatory = 0;
 159                 if (recvline(data, &buf))
 160                         exit(128);
 161
 162                 if (!*buf.buf)
 163                         break;
 164
 165                 if (*buf.buf == '*') {
 166                         capname = buf.buf + 1;
 167                         mandatory = 1;
 168                 } else
 169                         capname = buf.buf;
 170
 171                 if (debug)
 172                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 173                 if (!strcmp(capname, "fetch"))
 174                         data->fetch = 1;
 175                 else if (!strcmp(capname, "option"))
 176                         data->option = 1;
 177                 else if (!strcmp(capname, "push"))
 178                         data->push = 1;
 179                 else if (!strcmp(capname, "import"))
 180                         data->import = 1;
 181                 else if (!strcmp(capname, "bidi-import"))
 182                         data->bidi_import = 1;
 183                 else if (!strcmp(capname, "export"))
 184                         data->export = 1;
 185                 else if (!strcmp(capname, "check-connectivity"))
 186                         data->check_connectivity = 1;
 187                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 188                         ALLOC_GROW(refspecs,
 189                                    refspec_nr + 1,
 190                                    refspec_alloc);
 191                         refspecs[refspec_nr++] = xstrdup(arg);
 192                 } else if (!strcmp(capname, "connect")) {
 193                         data->connect = 1;
 194                 } else if (!strcmp(capname, "signed-tags")) {
 195                         data->signed_tags = 1;
 196                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 197                         data->export_marks = xstrdup(arg);
 198                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 199                         data->import_marks = xstrdup(arg);
 200                 } else if (starts_with(capname, "no-private-update")) {
 201                         data->no_private_update = 1;
 202                 } else if (mandatory) {
 203                         die("Unknown mandatory capability %s. This remote "
 204                             "helper probably needs newer version of Git.",
 205                             capname);
 206                 }
 207         }
 208         if (refspecs) {
 209                 int i;
 210                 data->refspec_nr = refspec_nr;
 211                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 212                 for (i = 0; i < refspec_nr; i++)
 213                         free((char *)refspecs[i]);
 214                 free(refspecs);
 215         } else if (data->import || data->bidi_import || data->export) {
 216                 warning("This remote helper should implement refspec capability.");
 217         }
 218         strbuf_release(&buf);
 219         if (debug)
 220                 fprintf(stderr, "Debug: Capabilities complete.\n");
 221         return data->helper;
 222 }
 223
 224 static int disconnect_helper(struct transport *transport)
 225 {
 226         struct helper_data *data = transport->data;
 227         int res = 0;
 228
 229         if (data->helper) {
 230                 if (debug)
 231                         fprintf(stderr, "Debug: Disconnecting.\n");
 232                 if (!data->no_disconnect_req) {
 233                         /*
 234                          * Ignore write errors; there's nothing we can do,
 235                          * since we're about to close the pipe anyway. And the
 236                          * most likely error is EPIPE due to the helper dying
 237                          * to report an error itself.
 238                          */
 239                         sigchain_push(SIGPIPE, SIG_IGN);
 240                         xwrite(data->helper->in, "\n", 1);
 241                         sigchain_pop(SIGPIPE);
 242                 }
 243                 close(data->helper->in);
 244                 close(data->helper->out);
 245                 fclose(data->out);
 246                 res = finish_command(data->helper);
 247                 free(data->helper);
 248                 data->helper = NULL;
 249         }
 250         return res;
 251 }
 252
 253 static const char *unsupported_options[] = {
 254         TRANS_OPT_UPLOADPACK,
 255         TRANS_OPT_RECEIVEPACK,
 256         TRANS_OPT_THIN,
 257         TRANS_OPT_KEEP
 258         };
 259
 260 static const char *boolean_options[] = {
 261         TRANS_OPT_THIN,
 262         TRANS_OPT_KEEP,
 263         TRANS_OPT_FOLLOWTAGS
 264         };
 265
 266 static int set_helper_option(struct transport *transport,
 267                           const char *name, const char *value)
 268 {
 269         struct helper_data *data = transport->data;
 270         struct strbuf buf = STRBUF_INIT;
 271         int i, ret, is_bool = 0;
 272
 273         get_helper(transport);
 274
 275         if (!data->option)
 276                 return 1;
 277
 278         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 279                 if (!strcmp(name, unsupported_options[i]))
 280                         return 1;
 281         }
 282
 283         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 284                 if (!strcmp(name, boolean_options[i])) {
 285                         is_bool = 1;
 286                         break;
 287                 }
 288         }
 289
 290         strbuf_addf(&buf, "option %s ", name);
 291         if (is_bool)
 292                 strbuf_addstr(&buf, value ? "true" : "false");
 293         else
 294                 quote_c_style(value, &buf, NULL, 0);
 295         strbuf_addch(&buf, '\n');
 296
 297         sendline(data, &buf);
 298         if (recvline(data, &buf))
 299                 exit(128);
 300
 301         if (!strcmp(buf.buf, "ok"))
 302                 ret = 0;
 303         else if (starts_with(buf.buf, "error")) {
 304                 ret = -1;
 305         } else if (!strcmp(buf.buf, "unsupported"))
 306                 ret = 1;
 307         else {
 308                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 309                 ret = 1;
 310         }
 311         strbuf_release(&buf);
 312         return ret;
 313 }
 314
 315 static void standard_options(struct transport *t)
 316 {
 317         char buf[16];
 318         int n;
 319         int v = t->verbose;
 320
 321         set_helper_option(t, "progress", t->progress ? "true" : "false");
 322
 323         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 324         if (n >= sizeof(buf))
 325                 die("impossibly large verbosity value");
 326         set_helper_option(t, "verbosity", buf);
 327 }
 328
 329 static int release_helper(struct transport *transport)
 330 {
 331         int res = 0;
 332         struct helper_data *data = transport->data;
 333         free_refspec(data->refspec_nr, data->refspecs);
 334         data->refspecs = NULL;
 335         res = disconnect_helper(transport);
 336         free(transport->data);
 337         return res;
 338 }
 339
 340 static int fetch_with_fetch(struct transport *transport,
 341                             int nr_heads, struct ref **to_fetch)
 342 {
 343         struct helper_data *data = transport->data;
 344         int i;
 345         struct strbuf buf = STRBUF_INIT;
 346
 347         standard_options(transport);
 348         if (data->check_connectivity &&
 349             data->transport_options.check_self_contained_and_connected)
 350                 set_helper_option(transport, "check-connectivity", "true");
 351
 352         if (transport->cloning)
 353                 set_helper_option(transport, "cloning", "true");
 354
 355         if (data->transport_options.update_shallow)
 356                 set_helper_option(transport, "update-shallow", "true");
 357
 358         for (i = 0; i < nr_heads; i++) {
 359                 const struct ref *posn = to_fetch[i];
 360                 if (posn->status & REF_STATUS_UPTODATE)
 361                         continue;
 362
 363                 strbuf_addf(&buf, "fetch %s %s\n",
 364                             sha1_to_hex(posn->old_sha1), posn->name);
 365         }
 366
 367         strbuf_addch(&buf, '\n');
 368         sendline(data, &buf);
 369
 370         while (1) {
 371                 if (recvline(data, &buf))
 372                         exit(128);
 373
 374                 if (starts_with(buf.buf, "lock ")) {
 375                         const char *name = buf.buf + 5;
 376                         if (transport->pack_lockfile)
 377                                 warning("%s also locked %s", data->name, name);
 378                         else
 379                                 transport->pack_lockfile = xstrdup(name);
 380                 }
 381                 else if (data->check_connectivity &&
 382                          data->transport_options.check_self_contained_and_connected &&
 383                          !strcmp(buf.buf, "connectivity-ok"))
 384                         data->transport_options.self_contained_and_connected = 1;
 385                 else if (!buf.len)
 386                         break;
 387                 else
 388                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 389         }
 390         strbuf_release(&buf);
 391         return 0;
 392 }
 393
 394 static int get_importer(struct transport *transport, struct child_process *fastimport)
 395 {
 396         struct child_process *helper = get_helper(transport);
 397         struct helper_data *data = transport->data;
 398         int cat_blob_fd, code;
 399         child_process_init(fastimport);
 400         fastimport->in = helper->out;
 401         argv_array_push(&fastimport->args, "fast-import");
 402         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 403
 404         if (data->bidi_import) {
 405                 cat_blob_fd = xdup(helper->in);
 406                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 407         }
 408         fastimport->git_cmd = 1;
 409
 410         code = start_command(fastimport);
 411         return code;
 412 }
 413
 414 static int get_exporter(struct transport *transport,
 415                         struct child_process *fastexport,
 416                         struct string_list *revlist_args)
 417 {
 418         struct helper_data *data = transport->data;
 419         struct child_process *helper = get_helper(transport);
 420         int i;
 421
 422         memset(fastexport, 0, sizeof(*fastexport));
 423
 424         /* we need to duplicate helper->in because we want to use it after
 425          * fastexport is done with it. */
 426         fastexport->out = dup(helper->in);
 427         argv_array_push(&fastexport->args, "fast-export");
 428         argv_array_push(&fastexport->args, "--use-done-feature");
 429         argv_array_push(&fastexport->args, data->signed_tags ?
 430                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 431         if (data->export_marks)
 432                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 433         if (data->import_marks)
 434                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 435
 436         for (i = 0; i < revlist_args->nr; i++)
 437                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 438
 439         fastexport->git_cmd = 1;
 440         return start_command(fastexport);
 441 }
 442
 443 static int fetch_with_import(struct transport *transport,
 444                              int nr_heads, struct ref **to_fetch)
 445 {
 446         struct child_process fastimport;
 447         struct helper_data *data = transport->data;
 448         int i;
 449         struct ref *posn;
 450         struct strbuf buf = STRBUF_INIT;
 451
 452         get_helper(transport);
 453
 454         if (get_importer(transport, &fastimport))
 455                 die("Couldn't run fast-import");
 456
 457         for (i = 0; i < nr_heads; i++) {
 458                 posn = to_fetch[i];
 459                 if (posn->status & REF_STATUS_UPTODATE)
 460                         continue;
 461
 462                 strbuf_addf(&buf, "import %s\n", posn->name);
 463                 sendline(data, &buf);
 464                 strbuf_reset(&buf);
 465         }
 466
 467         write_constant(data->helper->in, "\n");
 468         /*
 469          * remote-helpers that advertise the bidi-import capability are required to
 470          * buffer the complete batch of import commands until this newline before
 471          * sending data to fast-import.
 472          * These helpers read back data from fast-import on their stdin, which could
 473          * be mixed with import commands, otherwise.
 474          */
 475
 476         if (finish_command(&fastimport))
 477                 die("Error while running fast-import");
 478
 479         /*
 480          * The fast-import stream of a remote helper that advertises
 481          * the "refspec" capability writes to the refs named after the
 482          * right hand side of the first refspec matching each ref we
 483          * were fetching.
 484          *
 485          * (If no "refspec" capability was specified, for historical
 486          * reasons we default to the equivalent of *:*.)
 487          *
 488          * Store the result in to_fetch[i].old_sha1.  Callers such
 489          * as "git fetch" can use the value to write feedback to the
 490          * terminal, populate FETCH_HEAD, and determine what new value
 491          * should be written to peer_ref if the update is a
 492          * fast-forward or this is a forced update.
 493          */
 494         for (i = 0; i < nr_heads; i++) {
 495                 char *private;
 496                 posn = to_fetch[i];
 497                 if (posn->status & REF_STATUS_UPTODATE)
 498                         continue;
 499                 if (data->refspecs)
 500                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 501                 else
 502                         private = xstrdup(posn->name);
 503                 if (private) {
 504                         read_ref(private, posn->old_sha1);
 505                         free(private);
 506                 }
 507         }
 508         strbuf_release(&buf);
 509         return 0;
 510 }
 511
 512 static int process_connect_service(struct transport *transport,
 513                                    const char *name, const char *exec)
 514 {
 515         struct helper_data *data = transport->data;
 516         struct strbuf cmdbuf = STRBUF_INIT;
 517         struct child_process *helper;
 518         int r, duped, ret = 0;
 519         FILE *input;
 520
 521         helper = get_helper(transport);
 522
 523         /*
 524          * Yes, dup the pipe another time, as we need unbuffered version
 525          * of input pipe as FILE*. fclose() closes the underlying fd and
 526          * stream buffering only can be changed before first I/O operation
 527          * on it.
 528          */
 529         duped = dup(helper->out);
 530         if (duped < 0)
 531                 die_errno("Can't dup helper output fd");
 532         input = xfdopen(duped, "r");
 533         setvbuf(input, NULL, _IONBF, 0);
 534
 535         /*
 536          * Handle --upload-pack and friends. This is fire and forget...
 537          * just warn if it fails.
 538          */
 539         if (strcmp(name, exec)) {
 540                 r = set_helper_option(transport, "servpath", exec);
 541                 if (r > 0)
 542                         warning("Setting remote service path not supported by protocol.");
 543                 else if (r < 0)
 544                         warning("Invalid remote service path.");
 545         }
 546
 547         if (data->connect)
 548                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 549         else
 550                 goto exit;
 551
 552         sendline(data, &cmdbuf);
 553         if (recvline_fh(input, &cmdbuf, name))
 554                 exit(128);
 555
 556         if (!strcmp(cmdbuf.buf, "")) {
 557                 data->no_disconnect_req = 1;
 558                 if (debug)
 559                         fprintf(stderr, "Debug: Smart transport connection "
 560                                 "ready.\n");
 561                 ret = 1;
 562         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 563                 if (debug)
 564                         fprintf(stderr, "Debug: Falling back to dumb "
 565                                 "transport.\n");
 566         } else
 567                 die("Unknown response to connect: %s",
 568                         cmdbuf.buf);
 569
 570 exit:
 571         fclose(input);
 572         return ret;
 573 }
 574
 575 static int process_connect(struct transport *transport,
 576                                      int for_push)
 577 {
 578         struct helper_data *data = transport->data;
 579         const char *name;
 580         const char *exec;
 581
 582         name = for_push ? "git-receive-pack" : "git-upload-pack";
 583         if (for_push)
 584                 exec = data->transport_options.receivepack;
 585         else
 586                 exec = data->transport_options.uploadpack;
 587
 588         return process_connect_service(transport, name, exec);
 589 }
 590
 591 static int connect_helper(struct transport *transport, const char *name,
 592                    const char *exec, int fd[2])
 593 {
 594         struct helper_data *data = transport->data;
 595
 596         /* Get_helper so connect is inited. */
 597         get_helper(transport);
 598         if (!data->connect)
 599                 die("Operation not supported by protocol.");
 600
 601         if (!process_connect_service(transport, name, exec))
 602                 die("Can't connect to subservice %s.", name);
 603
 604         fd[0] = data->helper->out;
 605         fd[1] = data->helper->in;
 606         return 0;
 607 }
 608
 609 static int fetch(struct transport *transport,
 610                  int nr_heads, struct ref **to_fetch)
 611 {
 612         struct helper_data *data = transport->data;
 613         int i, count;
 614
 615         if (process_connect(transport, 0)) {
 616                 do_take_over(transport);
 617                 return transport->fetch(transport, nr_heads, to_fetch);
 618         }
 619
 620         count = 0;
 621         for (i = 0; i < nr_heads; i++)
 622                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 623                         count++;
 624
 625         if (!count)
 626                 return 0;
 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         standard_options(transport);
 833         for_each_string_list_item(cas_option, &cas_options)
 834                 set_helper_option(transport, "cas", cas_option->string);
 835
 836         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 837                 if (set_helper_option(transport, "dry-run", "true") != 0)
 838                         die("helper %s does not support dry-run", data->name);
 839         }
 840
 841         strbuf_addch(&buf, '\n');
 842         sendline(data, &buf);
 843         strbuf_release(&buf);
 844
 845         return push_update_refs_status(data, remote_refs, flags);
 846 }
 847
 848 static int push_refs_with_export(struct transport *transport,
 849                 struct ref *remote_refs, int flags)
 850 {
 851         struct ref *ref;
 852         struct child_process *helper, exporter;
 853         struct helper_data *data = transport->data;
 854         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 855         struct strbuf buf = STRBUF_INIT;
 856
 857         if (!data->refspecs)
 858                 die("remote-helper doesn't support push; refspec needed");
 859
 860         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 861                 if (set_helper_option(transport, "dry-run", "true") != 0)
 862                         die("helper %s does not support dry-run", data->name);
 863         }
 864
 865         if (flags & TRANSPORT_PUSH_FORCE) {
 866                 if (set_helper_option(transport, "force", "true") != 0)
 867                         warning("helper %s does not support 'force'", data->name);
 868         }
 869
 870         helper = get_helper(transport);
 871
 872         write_constant(helper->in, "export\n");
 873
 874         for (ref = remote_refs; ref; ref = ref->next) {
 875                 char *private;
 876                 unsigned char sha1[20];
 877
 878                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 879                 if (private && !get_sha1(private, sha1)) {
 880                         strbuf_addf(&buf, "^%s", private);
 881                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 882                         hashcpy(ref->old_sha1, sha1);
 883                 }
 884                 free(private);
 885
 886                 if (ref->peer_ref) {
 887                         if (strcmp(ref->name, ref->peer_ref->name)) {
 888                                 if (!ref->deletion) {
 889                                         const char *name;
 890                                         int flag;
 891
 892                                         /* Follow symbolic refs (mainly for HEAD). */
 893                                         name = resolve_ref_unsafe(ref->peer_ref->name, sha1, 1, &flag);
 894                                         if (!name || !(flag & REF_ISSYMREF))
 895                                                 name = ref->peer_ref->name;
 896
 897                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 898                                 } else
 899                                         strbuf_addf(&buf, ":%s", ref->name);
 900
 901                                 string_list_append(&revlist_args, "--refspec");
 902                                 string_list_append(&revlist_args, buf.buf);
 903                                 strbuf_release(&buf);
 904                         }
 905                         if (!ref->deletion)
 906                                 string_list_append(&revlist_args, ref->peer_ref->name);
 907                 }
 908         }
 909
 910         if (get_exporter(transport, &exporter, &revlist_args))
 911                 die("Couldn't run fast-export");
 912
 913         string_list_clear(&revlist_args, 1);
 914
 915         if (finish_command(&exporter))
 916                 die("Error while running fast-export");
 917         if (push_update_refs_status(data, remote_refs, flags))
 918                 return 1;
 919
 920         if (data->export_marks) {
 921                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 922                 rename(buf.buf, data->export_marks);
 923                 strbuf_release(&buf);
 924         }
 925
 926         return 0;
 927 }
 928
 929 static int push_refs(struct transport *transport,
 930                 struct ref *remote_refs, int flags)
 931 {
 932         struct helper_data *data = transport->data;
 933
 934         if (process_connect(transport, 1)) {
 935                 do_take_over(transport);
 936                 return transport->push_refs(transport, remote_refs, flags);
 937         }
 938
 939         if (!remote_refs) {
 940                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 941                         "Perhaps you should specify a branch such as 'master'.\n");
 942                 return 0;
 943         }
 944
 945         if (data->push)
 946                 return push_refs_with_push(transport, remote_refs, flags);
 947
 948         if (data->export)
 949                 return push_refs_with_export(transport, remote_refs, flags);
 950
 951         return -1;
 952 }
 953
 954
 955 static int has_attribute(const char *attrs, const char *attr) {
 956         int len;
 957         if (!attrs)
 958                 return 0;
 959
 960         len = strlen(attr);
 961         for (;;) {
 962                 const char *space = strchrnul(attrs, ' ');
 963                 if (len == space - attrs && !strncmp(attrs, attr, len))
 964                         return 1;
 965                 if (!*space)
 966                         return 0;
 967                 attrs = space + 1;
 968         }
 969 }
 970
 971 static struct ref *get_refs_list(struct transport *transport, int for_push)
 972 {
 973         struct helper_data *data = transport->data;
 974         struct child_process *helper;
 975         struct ref *ret = NULL;
 976         struct ref **tail = &ret;
 977         struct ref *posn;
 978         struct strbuf buf = STRBUF_INIT;
 979
 980         helper = get_helper(transport);
 981
 982         if (process_connect(transport, for_push)) {
 983                 do_take_over(transport);
 984                 return transport->get_refs_list(transport, for_push);
 985         }
 986
 987         if (data->push && for_push)
 988                 write_str_in_full(helper->in, "list for-push\n");
 989         else
 990                 write_str_in_full(helper->in, "list\n");
 991
 992         while (1) {
 993                 char *eov, *eon;
 994                 if (recvline(data, &buf))
 995                         exit(128);
 996
 997                 if (!*buf.buf)
 998                         break;
 999
1000                 eov = strchr(buf.buf, ' ');
1001                 if (!eov)
1002                         die("Malformed response in ref list: %s", buf.buf);
1003                 eon = strchr(eov + 1, ' ');
1004                 *eov = '\0';
1005                 if (eon)
1006                         *eon = '\0';
1007                 *tail = alloc_ref(eov + 1);
1008                 if (buf.buf[0] == '@')
1009                         (*tail)->symref = xstrdup(buf.buf + 1);
1010                 else if (buf.buf[0] != '?')
1011                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1012                 if (eon) {
1013                         if (has_attribute(eon + 1, "unchanged")) {
1014                                 (*tail)->status |= REF_STATUS_UPTODATE;
1015                                 read_ref((*tail)->name, (*tail)->old_sha1);
1016                         }
1017                 }
1018                 tail = &((*tail)->next);
1019         }
1020         if (debug)
1021                 fprintf(stderr, "Debug: Read ref listing.\n");
1022         strbuf_release(&buf);
1023
1024         for (posn = ret; posn; posn = posn->next)
1025                 resolve_remote_symref(posn, ret);
1026
1027         return ret;
1028 }
1029
1030 int transport_helper_init(struct transport *transport, const char *name)
1031 {
1032         struct helper_data *data = xcalloc(1, sizeof(*data));
1033         data->name = name;
1034
1035         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1036                 debug = 1;
1037
1038         transport->data = data;
1039         transport->set_option = set_helper_option;
1040         transport->get_refs_list = get_refs_list;
1041         transport->fetch = fetch;
1042         transport->push_refs = push_refs;
1043         transport->disconnect = release_helper;
1044         transport->connect = connect_helper;
1045         transport->smart_options = &(data->transport_options);
1046         return 0;
1047 }
1048
1049 /*
1050  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1051  * buffer less), so attempt reads and writes with up to that size.
1052  */
1053 #define BUFFERSIZE 65536
1054 /* This should be enough to hold debugging message. */
1055 #define PBUFFERSIZE 8192
1056
1057 /* Print bidirectional transfer loop debug message. */
1058 __attribute__((format (printf, 1, 2)))
1059 static void transfer_debug(const char *fmt, ...)
1060 {
1061         va_list args;
1062         char msgbuf[PBUFFERSIZE];
1063         static int debug_enabled = -1;
1064
1065         if (debug_enabled < 0)
1066                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1067         if (!debug_enabled)
1068                 return;
1069
1070         va_start(args, fmt);
1071         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1072         va_end(args);
1073         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1074 }
1075
1076 /* Stream state: More data may be coming in this direction. */
1077 #define SSTATE_TRANSFERING 0
1078 /*
1079  * Stream state: No more data coming in this direction, flushing rest of
1080  * data.
1081  */
1082 #define SSTATE_FLUSHING 1
1083 /* Stream state: Transfer in this direction finished. */
1084 #define SSTATE_FINISHED 2
1085
1086 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1087 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1088 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1089
1090 /* Unidirectional transfer. */
1091 struct unidirectional_transfer {
1092         /* Source */
1093         int src;
1094         /* Destination */
1095         int dest;
1096         /* Is source socket? */
1097         int src_is_sock;
1098         /* Is destination socket? */
1099         int dest_is_sock;
1100         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1101         int state;
1102         /* Buffer. */
1103         char buf[BUFFERSIZE];
1104         /* Buffer used. */
1105         size_t bufuse;
1106         /* Name of source. */
1107         const char *src_name;
1108         /* Name of destination. */
1109         const char *dest_name;
1110 };
1111
1112 /* Closes the target (for writing) if transfer has finished. */
1113 static void udt_close_if_finished(struct unidirectional_transfer *t)
1114 {
1115         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1116                 t->state = SSTATE_FINISHED;
1117                 if (t->dest_is_sock)
1118                         shutdown(t->dest, SHUT_WR);
1119                 else
1120                         close(t->dest);
1121                 transfer_debug("Closed %s.", t->dest_name);
1122         }
1123 }
1124
1125 /*
1126  * Tries to read read data from source into buffer. If buffer is full,
1127  * no data is read. Returns 0 on success, -1 on error.
1128  */
1129 static int udt_do_read(struct unidirectional_transfer *t)
1130 {
1131         ssize_t bytes;
1132
1133         if (t->bufuse == BUFFERSIZE)
1134                 return 0;       /* No space for more. */
1135
1136         transfer_debug("%s is readable", t->src_name);
1137         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1138         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1139                 errno != EINTR) {
1140                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1141                 return -1;
1142         } else if (bytes == 0) {
1143                 transfer_debug("%s EOF (with %i bytes in buffer)",
1144                         t->src_name, (int)t->bufuse);
1145                 t->state = SSTATE_FLUSHING;
1146         } else if (bytes > 0) {
1147                 t->bufuse += bytes;
1148                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1149                         (int)bytes, t->src_name, (int)t->bufuse);
1150         }
1151         return 0;
1152 }
1153
1154 /* Tries to write data from buffer into destination. If buffer is empty,
1155  * no data is written. Returns 0 on success, -1 on error.
1156  */
1157 static int udt_do_write(struct unidirectional_transfer *t)
1158 {
1159         ssize_t bytes;
1160
1161         if (t->bufuse == 0)
1162                 return 0;       /* Nothing to write. */
1163
1164         transfer_debug("%s is writable", t->dest_name);
1165         bytes = xwrite(t->dest, t->buf, t->bufuse);
1166         if (bytes < 0 && errno != EWOULDBLOCK) {
1167                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1168                 return -1;
1169         } else if (bytes > 0) {
1170                 t->bufuse -= bytes;
1171                 if (t->bufuse)
1172                         memmove(t->buf, t->buf + bytes, t->bufuse);
1173                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1174                         (int)bytes, t->dest_name, (int)t->bufuse);
1175         }
1176         return 0;
1177 }
1178
1179
1180 /* State of bidirectional transfer loop. */
1181 struct bidirectional_transfer_state {
1182         /* Direction from program to git. */
1183         struct unidirectional_transfer ptg;
1184         /* Direction from git to program. */
1185         struct unidirectional_transfer gtp;
1186 };
1187
1188 static void *udt_copy_task_routine(void *udt)
1189 {
1190         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1191         while (t->state != SSTATE_FINISHED) {
1192                 if (STATE_NEEDS_READING(t->state))
1193                         if (udt_do_read(t))
1194                                 return NULL;
1195                 if (STATE_NEEDS_WRITING(t->state))
1196                         if (udt_do_write(t))
1197                                 return NULL;
1198                 if (STATE_NEEDS_CLOSING(t->state))
1199                         udt_close_if_finished(t);
1200         }
1201         return udt;     /* Just some non-NULL value. */
1202 }
1203
1204 #ifndef NO_PTHREADS
1205
1206 /*
1207  * Join thread, with appropriate errors on failure. Name is name for the
1208  * thread (for error messages). Returns 0 on success, 1 on failure.
1209  */
1210 static int tloop_join(pthread_t thread, const char *name)
1211 {
1212         int err;
1213         void *tret;
1214         err = pthread_join(thread, &tret);
1215         if (!tret) {
1216                 error("%s thread failed", name);
1217                 return 1;
1218         }
1219         if (err) {
1220                 error("%s thread failed to join: %s", name, strerror(err));
1221                 return 1;
1222         }
1223         return 0;
1224 }
1225
1226 /*
1227  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1228  * -1 on failure.
1229  */
1230 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1231 {
1232         pthread_t gtp_thread;
1233         pthread_t ptg_thread;
1234         int err;
1235         int ret = 0;
1236         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1237                 &s->gtp);
1238         if (err)
1239                 die("Can't start thread for copying data: %s", strerror(err));
1240         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1241                 &s->ptg);
1242         if (err)
1243                 die("Can't start thread for copying data: %s", strerror(err));
1244
1245         ret |= tloop_join(gtp_thread, "Git to program copy");
1246         ret |= tloop_join(ptg_thread, "Program to git copy");
1247         return ret;
1248 }
1249 #else
1250
1251 /* Close the source and target (for writing) for transfer. */
1252 static void udt_kill_transfer(struct unidirectional_transfer *t)
1253 {
1254         t->state = SSTATE_FINISHED;
1255         /*
1256          * Socket read end left open isn't a disaster if nobody
1257          * attempts to read from it (mingw compat headers do not
1258          * have SHUT_RD)...
1259          *
1260          * We can't fully close the socket since otherwise gtp
1261          * task would first close the socket it sends data to
1262          * while closing the ptg file descriptors.
1263          */
1264         if (!t->src_is_sock)
1265                 close(t->src);
1266         if (t->dest_is_sock)
1267                 shutdown(t->dest, SHUT_WR);
1268         else
1269                 close(t->dest);
1270 }
1271
1272 /*
1273  * Join process, with appropriate errors on failure. Name is name for the
1274  * process (for error messages). Returns 0 on success, 1 on failure.
1275  */
1276 static int tloop_join(pid_t pid, const char *name)
1277 {
1278         int tret;
1279         if (waitpid(pid, &tret, 0) < 0) {
1280                 error("%s process failed to wait: %s", name, strerror(errno));
1281                 return 1;
1282         }
1283         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1284                 error("%s process failed", name);
1285                 return 1;
1286         }
1287         return 0;
1288 }
1289
1290 /*
1291  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1292  * -1 on failure.
1293  */
1294 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1295 {
1296         pid_t pid1, pid2;
1297         int ret = 0;
1298
1299         /* Fork thread #1: git to program. */
1300         pid1 = fork();
1301         if (pid1 < 0)
1302                 die_errno("Can't start thread for copying data");
1303         else if (pid1 == 0) {
1304                 udt_kill_transfer(&s->ptg);
1305                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1306         }
1307
1308         /* Fork thread #2: program to git. */
1309         pid2 = fork();
1310         if (pid2 < 0)
1311                 die_errno("Can't start thread for copying data");
1312         else if (pid2 == 0) {
1313                 udt_kill_transfer(&s->gtp);
1314                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1315         }
1316
1317         /*
1318          * Close both streams in parent as to not interfere with
1319          * end of file detection and wait for both tasks to finish.
1320          */
1321         udt_kill_transfer(&s->gtp);
1322         udt_kill_transfer(&s->ptg);
1323         ret |= tloop_join(pid1, "Git to program copy");
1324         ret |= tloop_join(pid2, "Program to git copy");
1325         return ret;
1326 }
1327 #endif
1328
1329 /*
1330  * Copies data from stdin to output and from input to stdout simultaneously.
1331  * Additionally filtering through given filter. If filter is NULL, uses
1332  * identity filter.
1333  */
1334 int bidirectional_transfer_loop(int input, int output)
1335 {
1336         struct bidirectional_transfer_state state;
1337
1338         /* Fill the state fields. */
1339         state.ptg.src = input;
1340         state.ptg.dest = 1;
1341         state.ptg.src_is_sock = (input == output);
1342         state.ptg.dest_is_sock = 0;
1343         state.ptg.state = SSTATE_TRANSFERING;
1344         state.ptg.bufuse = 0;
1345         state.ptg.src_name = "remote input";
1346         state.ptg.dest_name = "stdout";
1347
1348         state.gtp.src = 0;
1349         state.gtp.dest = output;
1350         state.gtp.src_is_sock = 0;
1351         state.gtp.dest_is_sock = (input == output);
1352         state.gtp.state = SSTATE_TRANSFERING;
1353         state.gtp.bufuse = 0;
1354         state.gtp.src_name = "stdin";
1355         state.gtp.dest_name = "remote output";
1356
1357         return tloop_spawnwait_tasks(&state);
1358 }