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 struct child_process *get_helper(struct transport *transport)
 101 {
 102         struct helper_data *data = transport->data;
 103         struct strbuf buf = STRBUF_INIT;
 104         struct child_process *helper;
 105         const char **refspecs = NULL;
 106         int refspec_nr = 0;
 107         int refspec_alloc = 0;
 108         int duped;
 109         int code;
 110
 111         if (data->helper)
 112                 return data->helper;
 113
 114         helper = xmalloc(sizeof(*helper));
 115         child_process_init(helper);
 116         helper->in = -1;
 117         helper->out = -1;
 118         helper->err = 0;
 119         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 120         argv_array_push(&helper->args, transport->remote->name);
 121         argv_array_push(&helper->args, remove_ext_force(transport->url));
 122         helper->git_cmd = 0;
 123         helper->silent_exec_failure = 1;
 124
 125         argv_array_pushf(&helper->env_array, "%s=%s", GIT_DIR_ENVIRONMENT,
 126                          get_git_dir());
 127
 128         code = start_command(helper);
 129         if (code < 0 && errno == ENOENT)
 130                 die("Unable to find remote helper for '%s'", data->name);
 131         else if (code != 0)
 132                 exit(code);
 133
 134         data->helper = helper;
 135         data->no_disconnect_req = 0;
 136
 137         /*
 138          * Open the output as FILE* so strbuf_getline() can be used.
 139          * Do this with duped fd because fclose() will close the fd,
 140          * and stuff like taking over will require the fd to remain.
 141          */
 142         duped = dup(helper->out);
 143         if (duped < 0)
 144                 die_errno("Can't dup helper output fd");
 145         data->out = xfdopen(duped, "r");
 146
 147         write_constant(helper->in, "capabilities\n");
 148
 149         while (1) {
 150                 const char *capname, *arg;
 151                 int mandatory = 0;
 152                 if (recvline(data, &buf))
 153                         exit(128);
 154
 155                 if (!*buf.buf)
 156                         break;
 157
 158                 if (*buf.buf == '*') {
 159                         capname = buf.buf + 1;
 160                         mandatory = 1;
 161                 } else
 162                         capname = buf.buf;
 163
 164                 if (debug)
 165                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 166                 if (!strcmp(capname, "fetch"))
 167                         data->fetch = 1;
 168                 else if (!strcmp(capname, "option"))
 169                         data->option = 1;
 170                 else if (!strcmp(capname, "push"))
 171                         data->push = 1;
 172                 else if (!strcmp(capname, "import"))
 173                         data->import = 1;
 174                 else if (!strcmp(capname, "bidi-import"))
 175                         data->bidi_import = 1;
 176                 else if (!strcmp(capname, "export"))
 177                         data->export = 1;
 178                 else if (!strcmp(capname, "check-connectivity"))
 179                         data->check_connectivity = 1;
 180                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 181                         ALLOC_GROW(refspecs,
 182                                    refspec_nr + 1,
 183                                    refspec_alloc);
 184                         refspecs[refspec_nr++] = xstrdup(arg);
 185                 } else if (!strcmp(capname, "connect")) {
 186                         data->connect = 1;
 187                 } else if (!strcmp(capname, "signed-tags")) {
 188                         data->signed_tags = 1;
 189                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 190                         data->export_marks = xstrdup(arg);
 191                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 192                         data->import_marks = xstrdup(arg);
 193                 } else if (starts_with(capname, "no-private-update")) {
 194                         data->no_private_update = 1;
 195                 } else if (mandatory) {
 196                         die("Unknown mandatory capability %s. This remote "
 197                             "helper probably needs newer version of Git.",
 198                             capname);
 199                 }
 200         }
 201         if (refspecs) {
 202                 int i;
 203                 data->refspec_nr = refspec_nr;
 204                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 205                 for (i = 0; i < refspec_nr; i++)
 206                         free((char *)refspecs[i]);
 207                 free(refspecs);
 208         } else if (data->import || data->bidi_import || data->export) {
 209                 warning("This remote helper should implement refspec capability.");
 210         }
 211         strbuf_release(&buf);
 212         if (debug)
 213                 fprintf(stderr, "Debug: Capabilities complete.\n");
 214         return data->helper;
 215 }
 216
 217 static int disconnect_helper(struct transport *transport)
 218 {
 219         struct helper_data *data = transport->data;
 220         int res = 0;
 221
 222         if (data->helper) {
 223                 if (debug)
 224                         fprintf(stderr, "Debug: Disconnecting.\n");
 225                 if (!data->no_disconnect_req) {
 226                         /*
 227                          * Ignore write errors; there's nothing we can do,
 228                          * since we're about to close the pipe anyway. And the
 229                          * most likely error is EPIPE due to the helper dying
 230                          * to report an error itself.
 231                          */
 232                         sigchain_push(SIGPIPE, SIG_IGN);
 233                         xwrite(data->helper->in, "\n", 1);
 234                         sigchain_pop(SIGPIPE);
 235                 }
 236                 close(data->helper->in);
 237                 close(data->helper->out);
 238                 fclose(data->out);
 239                 res = finish_command(data->helper);
 240                 free(data->helper);
 241                 data->helper = NULL;
 242         }
 243         return res;
 244 }
 245
 246 static const char *unsupported_options[] = {
 247         TRANS_OPT_UPLOADPACK,
 248         TRANS_OPT_RECEIVEPACK,
 249         TRANS_OPT_THIN,
 250         TRANS_OPT_KEEP
 251         };
 252
 253 static const char *boolean_options[] = {
 254         TRANS_OPT_THIN,
 255         TRANS_OPT_KEEP,
 256         TRANS_OPT_FOLLOWTAGS,
 257         TRANS_OPT_PUSH_CERT
 258         };
 259
 260 static int set_helper_option(struct transport *transport,
 261                           const char *name, const char *value)
 262 {
 263         struct helper_data *data = transport->data;
 264         struct strbuf buf = STRBUF_INIT;
 265         int i, ret, is_bool = 0;
 266
 267         get_helper(transport);
 268
 269         if (!data->option)
 270                 return 1;
 271
 272         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 273                 if (!strcmp(name, unsupported_options[i]))
 274                         return 1;
 275         }
 276
 277         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 278                 if (!strcmp(name, boolean_options[i])) {
 279                         is_bool = 1;
 280                         break;
 281                 }
 282         }
 283
 284         strbuf_addf(&buf, "option %s ", name);
 285         if (is_bool)
 286                 strbuf_addstr(&buf, value ? "true" : "false");
 287         else
 288                 quote_c_style(value, &buf, NULL, 0);
 289         strbuf_addch(&buf, '\n');
 290
 291         sendline(data, &buf);
 292         if (recvline(data, &buf))
 293                 exit(128);
 294
 295         if (!strcmp(buf.buf, "ok"))
 296                 ret = 0;
 297         else if (starts_with(buf.buf, "error")) {
 298                 ret = -1;
 299         } else if (!strcmp(buf.buf, "unsupported"))
 300                 ret = 1;
 301         else {
 302                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 303                 ret = 1;
 304         }
 305         strbuf_release(&buf);
 306         return ret;
 307 }
 308
 309 static void standard_options(struct transport *t)
 310 {
 311         char buf[16];
 312         int n;
 313         int v = t->verbose;
 314
 315         set_helper_option(t, "progress", t->progress ? "true" : "false");
 316
 317         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 318         if (n >= sizeof(buf))
 319                 die("impossibly large verbosity value");
 320         set_helper_option(t, "verbosity", buf);
 321 }
 322
 323 static int release_helper(struct transport *transport)
 324 {
 325         int res = 0;
 326         struct helper_data *data = transport->data;
 327         free_refspec(data->refspec_nr, data->refspecs);
 328         data->refspecs = NULL;
 329         res = disconnect_helper(transport);
 330         free(transport->data);
 331         return res;
 332 }
 333
 334 static int fetch_with_fetch(struct transport *transport,
 335                             int nr_heads, struct ref **to_fetch)
 336 {
 337         struct helper_data *data = transport->data;
 338         int i;
 339         struct strbuf buf = STRBUF_INIT;
 340
 341         standard_options(transport);
 342         if (data->check_connectivity &&
 343             data->transport_options.check_self_contained_and_connected)
 344                 set_helper_option(transport, "check-connectivity", "true");
 345
 346         if (transport->cloning)
 347                 set_helper_option(transport, "cloning", "true");
 348
 349         if (data->transport_options.update_shallow)
 350                 set_helper_option(transport, "update-shallow", "true");
 351
 352         for (i = 0; i < nr_heads; i++) {
 353                 const struct ref *posn = to_fetch[i];
 354                 if (posn->status & REF_STATUS_UPTODATE)
 355                         continue;
 356
 357                 strbuf_addf(&buf, "fetch %s %s\n",
 358                             sha1_to_hex(posn->old_sha1),
 359                             posn->symref ? posn->symref : posn->name);
 360         }
 361
 362         strbuf_addch(&buf, '\n');
 363         sendline(data, &buf);
 364
 365         while (1) {
 366                 if (recvline(data, &buf))
 367                         exit(128);
 368
 369                 if (starts_with(buf.buf, "lock ")) {
 370                         const char *name = buf.buf + 5;
 371                         if (transport->pack_lockfile)
 372                                 warning("%s also locked %s", data->name, name);
 373                         else
 374                                 transport->pack_lockfile = xstrdup(name);
 375                 }
 376                 else if (data->check_connectivity &&
 377                          data->transport_options.check_self_contained_and_connected &&
 378                          !strcmp(buf.buf, "connectivity-ok"))
 379                         data->transport_options.self_contained_and_connected = 1;
 380                 else if (!buf.len)
 381                         break;
 382                 else
 383                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 384         }
 385         strbuf_release(&buf);
 386         return 0;
 387 }
 388
 389 static int get_importer(struct transport *transport, struct child_process *fastimport)
 390 {
 391         struct child_process *helper = get_helper(transport);
 392         struct helper_data *data = transport->data;
 393         int cat_blob_fd, code;
 394         child_process_init(fastimport);
 395         fastimport->in = helper->out;
 396         argv_array_push(&fastimport->args, "fast-import");
 397         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 398
 399         if (data->bidi_import) {
 400                 cat_blob_fd = xdup(helper->in);
 401                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 402         }
 403         fastimport->git_cmd = 1;
 404
 405         code = start_command(fastimport);
 406         return code;
 407 }
 408
 409 static int get_exporter(struct transport *transport,
 410                         struct child_process *fastexport,
 411                         struct string_list *revlist_args)
 412 {
 413         struct helper_data *data = transport->data;
 414         struct child_process *helper = get_helper(transport);
 415         int i;
 416
 417         child_process_init(fastexport);
 418
 419         /* we need to duplicate helper->in because we want to use it after
 420          * fastexport is done with it. */
 421         fastexport->out = dup(helper->in);
 422         argv_array_push(&fastexport->args, "fast-export");
 423         argv_array_push(&fastexport->args, "--use-done-feature");
 424         argv_array_push(&fastexport->args, data->signed_tags ?
 425                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 426         if (data->export_marks)
 427                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 428         if (data->import_marks)
 429                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 430
 431         for (i = 0; i < revlist_args->nr; i++)
 432                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 433
 434         fastexport->git_cmd = 1;
 435         return start_command(fastexport);
 436 }
 437
 438 static int fetch_with_import(struct transport *transport,
 439                              int nr_heads, struct ref **to_fetch)
 440 {
 441         struct child_process fastimport;
 442         struct helper_data *data = transport->data;
 443         int i;
 444         struct ref *posn;
 445         struct strbuf buf = STRBUF_INIT;
 446
 447         get_helper(transport);
 448
 449         if (get_importer(transport, &fastimport))
 450                 die("Couldn't run fast-import");
 451
 452         for (i = 0; i < nr_heads; i++) {
 453                 posn = to_fetch[i];
 454                 if (posn->status & REF_STATUS_UPTODATE)
 455                         continue;
 456
 457                 strbuf_addf(&buf, "import %s\n",
 458                             posn->symref ? posn->symref : posn->name);
 459                 sendline(data, &buf);
 460                 strbuf_reset(&buf);
 461         }
 462
 463         write_constant(data->helper->in, "\n");
 464         /*
 465          * remote-helpers that advertise the bidi-import capability are required to
 466          * buffer the complete batch of import commands until this newline before
 467          * sending data to fast-import.
 468          * These helpers read back data from fast-import on their stdin, which could
 469          * be mixed with import commands, otherwise.
 470          */
 471
 472         if (finish_command(&fastimport))
 473                 die("Error while running fast-import");
 474
 475         /*
 476          * The fast-import stream of a remote helper that advertises
 477          * the "refspec" capability writes to the refs named after the
 478          * right hand side of the first refspec matching each ref we
 479          * were fetching.
 480          *
 481          * (If no "refspec" capability was specified, for historical
 482          * reasons we default to the equivalent of *:*.)
 483          *
 484          * Store the result in to_fetch[i].old_sha1.  Callers such
 485          * as "git fetch" can use the value to write feedback to the
 486          * terminal, populate FETCH_HEAD, and determine what new value
 487          * should be written to peer_ref if the update is a
 488          * fast-forward or this is a forced update.
 489          */
 490         for (i = 0; i < nr_heads; i++) {
 491                 char *private, *name;
 492                 posn = to_fetch[i];
 493                 if (posn->status & REF_STATUS_UPTODATE)
 494                         continue;
 495                 name = posn->symref ? posn->symref : posn->name;
 496                 if (data->refspecs)
 497                         private = apply_refspecs(data->refspecs, data->refspec_nr, name);
 498                 else
 499                         private = xstrdup(name);
 500                 if (private) {
 501                         read_ref(private, posn->old_sha1);
 502                         free(private);
 503                 }
 504         }
 505         strbuf_release(&buf);
 506         return 0;
 507 }
 508
 509 static int process_connect_service(struct transport *transport,
 510                                    const char *name, const char *exec)
 511 {
 512         struct helper_data *data = transport->data;
 513         struct strbuf cmdbuf = STRBUF_INIT;
 514         struct child_process *helper;
 515         int r, duped, ret = 0;
 516         FILE *input;
 517
 518         helper = get_helper(transport);
 519
 520         /*
 521          * Yes, dup the pipe another time, as we need unbuffered version
 522          * of input pipe as FILE*. fclose() closes the underlying fd and
 523          * stream buffering only can be changed before first I/O operation
 524          * on it.
 525          */
 526         duped = dup(helper->out);
 527         if (duped < 0)
 528                 die_errno("Can't dup helper output fd");
 529         input = xfdopen(duped, "r");
 530         setvbuf(input, NULL, _IONBF, 0);
 531
 532         /*
 533          * Handle --upload-pack and friends. This is fire and forget...
 534          * just warn if it fails.
 535          */
 536         if (strcmp(name, exec)) {
 537                 r = set_helper_option(transport, "servpath", exec);
 538                 if (r > 0)
 539                         warning("Setting remote service path not supported by protocol.");
 540                 else if (r < 0)
 541                         warning("Invalid remote service path.");
 542         }
 543
 544         if (data->connect)
 545                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 546         else
 547                 goto exit;
 548
 549         sendline(data, &cmdbuf);
 550         if (recvline_fh(input, &cmdbuf, name))
 551                 exit(128);
 552
 553         if (!strcmp(cmdbuf.buf, "")) {
 554                 data->no_disconnect_req = 1;
 555                 if (debug)
 556                         fprintf(stderr, "Debug: Smart transport connection "
 557                                 "ready.\n");
 558                 ret = 1;
 559         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 560                 if (debug)
 561                         fprintf(stderr, "Debug: Falling back to dumb "
 562                                 "transport.\n");
 563         } else
 564                 die("Unknown response to connect: %s",
 565                         cmdbuf.buf);
 566
 567 exit:
 568         fclose(input);
 569         return ret;
 570 }
 571
 572 static int process_connect(struct transport *transport,
 573                                      int for_push)
 574 {
 575         struct helper_data *data = transport->data;
 576         const char *name;
 577         const char *exec;
 578
 579         name = for_push ? "git-receive-pack" : "git-upload-pack";
 580         if (for_push)
 581                 exec = data->transport_options.receivepack;
 582         else
 583                 exec = data->transport_options.uploadpack;
 584
 585         return process_connect_service(transport, name, exec);
 586 }
 587
 588 static int connect_helper(struct transport *transport, const char *name,
 589                    const char *exec, int fd[2])
 590 {
 591         struct helper_data *data = transport->data;
 592
 593         /* Get_helper so connect is inited. */
 594         get_helper(transport);
 595         if (!data->connect)
 596                 die("Operation not supported by protocol.");
 597
 598         if (!process_connect_service(transport, name, exec))
 599                 die("Can't connect to subservice %s.", name);
 600
 601         fd[0] = data->helper->out;
 602         fd[1] = data->helper->in;
 603         return 0;
 604 }
 605
 606 static int fetch(struct transport *transport,
 607                  int nr_heads, struct ref **to_fetch)
 608 {
 609         struct helper_data *data = transport->data;
 610         int i, count;
 611
 612         if (process_connect(transport, 0)) {
 613                 do_take_over(transport);
 614                 return transport->fetch(transport, nr_heads, to_fetch);
 615         }
 616
 617         count = 0;
 618         for (i = 0; i < nr_heads; i++)
 619                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 620                         count++;
 621
 622         if (!count)
 623                 return 0;
 624
 625         if (data->fetch)
 626                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 627
 628         if (data->import)
 629                 return fetch_with_import(transport, nr_heads, to_fetch);
 630
 631         return -1;
 632 }
 633
 634 static int push_update_ref_status(struct strbuf *buf,
 635                                    struct ref **ref,
 636                                    struct ref *remote_refs)
 637 {
 638         char *refname, *msg;
 639         int status, forced = 0;
 640
 641         if (starts_with(buf->buf, "ok ")) {
 642                 status = REF_STATUS_OK;
 643                 refname = buf->buf + 3;
 644         } else if (starts_with(buf->buf, "error ")) {
 645                 status = REF_STATUS_REMOTE_REJECT;
 646                 refname = buf->buf + 6;
 647         } else
 648                 die("expected ok/error, helper said '%s'", buf->buf);
 649
 650         msg = strchr(refname, ' ');
 651         if (msg) {
 652                 struct strbuf msg_buf = STRBUF_INIT;
 653                 const char *end;
 654
 655                 *msg++ = '\0';
 656                 if (!unquote_c_style(&msg_buf, msg, &end))
 657                         msg = strbuf_detach(&msg_buf, NULL);
 658                 else
 659                         msg = xstrdup(msg);
 660                 strbuf_release(&msg_buf);
 661
 662                 if (!strcmp(msg, "no match")) {
 663                         status = REF_STATUS_NONE;
 664                         free(msg);
 665                         msg = NULL;
 666                 }
 667                 else if (!strcmp(msg, "up to date")) {
 668                         status = REF_STATUS_UPTODATE;
 669                         free(msg);
 670                         msg = NULL;
 671                 }
 672                 else if (!strcmp(msg, "non-fast forward")) {
 673                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 674                         free(msg);
 675                         msg = NULL;
 676                 }
 677                 else if (!strcmp(msg, "already exists")) {
 678                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 679                         free(msg);
 680                         msg = NULL;
 681                 }
 682                 else if (!strcmp(msg, "fetch first")) {
 683                         status = REF_STATUS_REJECT_FETCH_FIRST;
 684                         free(msg);
 685                         msg = NULL;
 686                 }
 687                 else if (!strcmp(msg, "needs force")) {
 688                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 689                         free(msg);
 690                         msg = NULL;
 691                 }
 692                 else if (!strcmp(msg, "stale info")) {
 693                         status = REF_STATUS_REJECT_STALE;
 694                         free(msg);
 695                         msg = NULL;
 696                 }
 697                 else if (!strcmp(msg, "forced update")) {
 698                         forced = 1;
 699                         free(msg);
 700                         msg = NULL;
 701                 }
 702         }
 703
 704         if (*ref)
 705                 *ref = find_ref_by_name(*ref, refname);
 706         if (!*ref)
 707                 *ref = find_ref_by_name(remote_refs, refname);
 708         if (!*ref) {
 709                 warning("helper reported unexpected status of %s", refname);
 710                 return 1;
 711         }
 712
 713         if ((*ref)->status != REF_STATUS_NONE) {
 714                 /*
 715                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 716                  * status reported by the remote helper if the latter is 'no match'.
 717                  */
 718                 if (status == REF_STATUS_NONE)
 719                         return 1;
 720         }
 721
 722         (*ref)->status = status;
 723         (*ref)->forced_update |= forced;
 724         (*ref)->remote_status = msg;
 725         return !(status == REF_STATUS_OK);
 726 }
 727
 728 static int push_update_refs_status(struct helper_data *data,
 729                                     struct ref *remote_refs,
 730                                     int flags)
 731 {
 732         struct strbuf buf = STRBUF_INIT;
 733         struct ref *ref = remote_refs;
 734         int ret = 0;
 735
 736         for (;;) {
 737                 char *private;
 738
 739                 if (recvline(data, &buf)) {
 740                         ret = 1;
 741                         break;
 742                 }
 743
 744                 if (!buf.len)
 745                         break;
 746
 747                 if (push_update_ref_status(&buf, &ref, remote_refs))
 748                         continue;
 749
 750                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 751                         continue;
 752
 753                 /* propagate back the update to the remote namespace */
 754                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 755                 if (!private)
 756                         continue;
 757                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 758                 free(private);
 759         }
 760         strbuf_release(&buf);
 761         return ret;
 762 }
 763
 764 static int push_refs_with_push(struct transport *transport,
 765                                struct ref *remote_refs, int flags)
 766 {
 767         int force_all = flags & TRANSPORT_PUSH_FORCE;
 768         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 769         struct helper_data *data = transport->data;
 770         struct strbuf buf = STRBUF_INIT;
 771         struct ref *ref;
 772         struct string_list cas_options = STRING_LIST_INIT_DUP;
 773         struct string_list_item *cas_option;
 774
 775         get_helper(transport);
 776         if (!data->push)
 777                 return 1;
 778
 779         for (ref = remote_refs; ref; ref = ref->next) {
 780                 if (!ref->peer_ref && !mirror)
 781                         continue;
 782
 783                 /* Check for statuses set by set_ref_status_for_push() */
 784                 switch (ref->status) {
 785                 case REF_STATUS_REJECT_NONFASTFORWARD:
 786                 case REF_STATUS_REJECT_STALE:
 787                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 788                 case REF_STATUS_UPTODATE:
 789                         continue;
 790                 default:
 791                         ; /* do nothing */
 792                 }
 793
 794                 if (force_all)
 795                         ref->force = 1;
 796
 797                 strbuf_addstr(&buf, "push ");
 798                 if (!ref->deletion) {
 799                         if (ref->force)
 800                                 strbuf_addch(&buf, '+');
 801                         if (ref->peer_ref)
 802                                 strbuf_addstr(&buf, ref->peer_ref->name);
 803                         else
 804                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 805                 }
 806                 strbuf_addch(&buf, ':');
 807                 strbuf_addstr(&buf, ref->name);
 808                 strbuf_addch(&buf, '\n');
 809
 810                 /*
 811                  * The "--force-with-lease" options without explicit
 812                  * values to expect have already been expanded into
 813                  * the ref->old_sha1_expect[] field; we can ignore
 814                  * transport->smart_options->cas altogether and instead
 815                  * can enumerate them from the refs.
 816                  */
 817                 if (ref->expect_old_sha1) {
 818                         struct strbuf cas = STRBUF_INIT;
 819                         strbuf_addf(&cas, "%s:%s",
 820                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 821                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 822                 }
 823         }
 824         if (buf.len == 0) {
 825                 string_list_clear(&cas_options, 0);
 826                 return 0;
 827         }
 828
 829         standard_options(transport);
 830         for_each_string_list_item(cas_option, &cas_options)
 831                 set_helper_option(transport, "cas", cas_option->string);
 832
 833         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 834                 if (set_helper_option(transport, "dry-run", "true") != 0)
 835                         die("helper %s does not support dry-run", data->name);
 836         } else if (flags & TRANSPORT_PUSH_CERT) {
 837                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 838                         die("helper %s does not support --signed", 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         } else if (flags & TRANSPORT_PUSH_CERT) {
 864                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 865                         die("helper %s does not support --signed", data->name);
 866         }
 867
 868         if (flags & TRANSPORT_PUSH_FORCE) {
 869                 if (set_helper_option(transport, "force", "true") != 0)
 870                         warning("helper %s does not support 'force'", data->name);
 871         }
 872
 873         helper = get_helper(transport);
 874
 875         write_constant(helper->in, "export\n");
 876
 877         for (ref = remote_refs; ref; ref = ref->next) {
 878                 char *private;
 879                 unsigned char sha1[20];
 880
 881                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 882                 if (private && !get_sha1(private, sha1)) {
 883                         strbuf_addf(&buf, "^%s", private);
 884                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 885                         hashcpy(ref->old_sha1, sha1);
 886                 }
 887                 free(private);
 888
 889                 if (ref->peer_ref) {
 890                         if (strcmp(ref->name, ref->peer_ref->name)) {
 891                                 if (!ref->deletion) {
 892                                         const char *name;
 893                                         int flag;
 894
 895                                         /* Follow symbolic refs (mainly for HEAD). */
 896                                         name = resolve_ref_unsafe(
 897                                                  ref->peer_ref->name,
 898                                                  RESOLVE_REF_READING,
 899                                                  sha1, &flag);
 900                                         if (!name || !(flag & REF_ISSYMREF))
 901                                                 name = ref->peer_ref->name;
 902
 903                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 904                                 } else
 905                                         strbuf_addf(&buf, ":%s", ref->name);
 906
 907                                 string_list_append(&revlist_args, "--refspec");
 908                                 string_list_append(&revlist_args, buf.buf);
 909                                 strbuf_release(&buf);
 910                         }
 911                         if (!ref->deletion)
 912                                 string_list_append(&revlist_args, ref->peer_ref->name);
 913                 }
 914         }
 915
 916         if (get_exporter(transport, &exporter, &revlist_args))
 917                 die("Couldn't run fast-export");
 918
 919         string_list_clear(&revlist_args, 1);
 920
 921         if (finish_command(&exporter))
 922                 die("Error while running fast-export");
 923         if (push_update_refs_status(data, remote_refs, flags))
 924                 return 1;
 925
 926         if (data->export_marks) {
 927                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 928                 rename(buf.buf, data->export_marks);
 929                 strbuf_release(&buf);
 930         }
 931
 932         return 0;
 933 }
 934
 935 static int push_refs(struct transport *transport,
 936                 struct ref *remote_refs, int flags)
 937 {
 938         struct helper_data *data = transport->data;
 939
 940         if (process_connect(transport, 1)) {
 941                 do_take_over(transport);
 942                 return transport->push_refs(transport, remote_refs, flags);
 943         }
 944
 945         if (!remote_refs) {
 946                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 947                         "Perhaps you should specify a branch such as 'master'.\n");
 948                 return 0;
 949         }
 950
 951         if (data->push)
 952                 return push_refs_with_push(transport, remote_refs, flags);
 953
 954         if (data->export)
 955                 return push_refs_with_export(transport, remote_refs, flags);
 956
 957         return -1;
 958 }
 959
 960
 961 static int has_attribute(const char *attrs, const char *attr) {
 962         int len;
 963         if (!attrs)
 964                 return 0;
 965
 966         len = strlen(attr);
 967         for (;;) {
 968                 const char *space = strchrnul(attrs, ' ');
 969                 if (len == space - attrs && !strncmp(attrs, attr, len))
 970                         return 1;
 971                 if (!*space)
 972                         return 0;
 973                 attrs = space + 1;
 974         }
 975 }
 976
 977 static struct ref *get_refs_list(struct transport *transport, int for_push)
 978 {
 979         struct helper_data *data = transport->data;
 980         struct child_process *helper;
 981         struct ref *ret = NULL;
 982         struct ref **tail = &ret;
 983         struct ref *posn;
 984         struct strbuf buf = STRBUF_INIT;
 985
 986         helper = get_helper(transport);
 987
 988         if (process_connect(transport, for_push)) {
 989                 do_take_over(transport);
 990                 return transport->get_refs_list(transport, for_push);
 991         }
 992
 993         if (data->push && for_push)
 994                 write_str_in_full(helper->in, "list for-push\n");
 995         else
 996                 write_str_in_full(helper->in, "list\n");
 997
 998         while (1) {
 999                 char *eov, *eon;
1000                 if (recvline(data, &buf))
1001                         exit(128);
1002
1003                 if (!*buf.buf)
1004                         break;
1005
1006                 eov = strchr(buf.buf, ' ');
1007                 if (!eov)
1008                         die("Malformed response in ref list: %s", buf.buf);
1009                 eon = strchr(eov + 1, ' ');
1010                 *eov = '\0';
1011                 if (eon)
1012                         *eon = '\0';
1013                 *tail = alloc_ref(eov + 1);
1014                 if (buf.buf[0] == '@')
1015                         (*tail)->symref = xstrdup(buf.buf + 1);
1016                 else if (buf.buf[0] != '?')
1017                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1018                 if (eon) {
1019                         if (has_attribute(eon + 1, "unchanged")) {
1020                                 (*tail)->status |= REF_STATUS_UPTODATE;
1021                                 read_ref((*tail)->name, (*tail)->old_sha1);
1022                         }
1023                 }
1024                 tail = &((*tail)->next);
1025         }
1026         if (debug)
1027                 fprintf(stderr, "Debug: Read ref listing.\n");
1028         strbuf_release(&buf);
1029
1030         for (posn = ret; posn; posn = posn->next)
1031                 resolve_remote_symref(posn, ret);
1032
1033         return ret;
1034 }
1035
1036 int transport_helper_init(struct transport *transport, const char *name)
1037 {
1038         struct helper_data *data = xcalloc(1, sizeof(*data));
1039         data->name = name;
1040
1041         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1042                 debug = 1;
1043
1044         transport->data = data;
1045         transport->set_option = set_helper_option;
1046         transport->get_refs_list = get_refs_list;
1047         transport->fetch = fetch;
1048         transport->push_refs = push_refs;
1049         transport->disconnect = release_helper;
1050         transport->connect = connect_helper;
1051         transport->smart_options = &(data->transport_options);
1052         return 0;
1053 }
1054
1055 /*
1056  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1057  * buffer less), so attempt reads and writes with up to that size.
1058  */
1059 #define BUFFERSIZE 65536
1060 /* This should be enough to hold debugging message. */
1061 #define PBUFFERSIZE 8192
1062
1063 /* Print bidirectional transfer loop debug message. */
1064 __attribute__((format (printf, 1, 2)))
1065 static void transfer_debug(const char *fmt, ...)
1066 {
1067         va_list args;
1068         char msgbuf[PBUFFERSIZE];
1069         static int debug_enabled = -1;
1070
1071         if (debug_enabled < 0)
1072                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1073         if (!debug_enabled)
1074                 return;
1075
1076         va_start(args, fmt);
1077         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1078         va_end(args);
1079         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1080 }
1081
1082 /* Stream state: More data may be coming in this direction. */
1083 #define SSTATE_TRANSFERING 0
1084 /*
1085  * Stream state: No more data coming in this direction, flushing rest of
1086  * data.
1087  */
1088 #define SSTATE_FLUSHING 1
1089 /* Stream state: Transfer in this direction finished. */
1090 #define SSTATE_FINISHED 2
1091
1092 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1093 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1094 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1095
1096 /* Unidirectional transfer. */
1097 struct unidirectional_transfer {
1098         /* Source */
1099         int src;
1100         /* Destination */
1101         int dest;
1102         /* Is source socket? */
1103         int src_is_sock;
1104         /* Is destination socket? */
1105         int dest_is_sock;
1106         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1107         int state;
1108         /* Buffer. */
1109         char buf[BUFFERSIZE];
1110         /* Buffer used. */
1111         size_t bufuse;
1112         /* Name of source. */
1113         const char *src_name;
1114         /* Name of destination. */
1115         const char *dest_name;
1116 };
1117
1118 /* Closes the target (for writing) if transfer has finished. */
1119 static void udt_close_if_finished(struct unidirectional_transfer *t)
1120 {
1121         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1122                 t->state = SSTATE_FINISHED;
1123                 if (t->dest_is_sock)
1124                         shutdown(t->dest, SHUT_WR);
1125                 else
1126                         close(t->dest);
1127                 transfer_debug("Closed %s.", t->dest_name);
1128         }
1129 }
1130
1131 /*
1132  * Tries to read read data from source into buffer. If buffer is full,
1133  * no data is read. Returns 0 on success, -1 on error.
1134  */
1135 static int udt_do_read(struct unidirectional_transfer *t)
1136 {
1137         ssize_t bytes;
1138
1139         if (t->bufuse == BUFFERSIZE)
1140                 return 0;       /* No space for more. */
1141
1142         transfer_debug("%s is readable", t->src_name);
1143         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1144         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1145                 errno != EINTR) {
1146                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1147                 return -1;
1148         } else if (bytes == 0) {
1149                 transfer_debug("%s EOF (with %i bytes in buffer)",
1150                         t->src_name, (int)t->bufuse);
1151                 t->state = SSTATE_FLUSHING;
1152         } else if (bytes > 0) {
1153                 t->bufuse += bytes;
1154                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1155                         (int)bytes, t->src_name, (int)t->bufuse);
1156         }
1157         return 0;
1158 }
1159
1160 /* Tries to write data from buffer into destination. If buffer is empty,
1161  * no data is written. Returns 0 on success, -1 on error.
1162  */
1163 static int udt_do_write(struct unidirectional_transfer *t)
1164 {
1165         ssize_t bytes;
1166
1167         if (t->bufuse == 0)
1168                 return 0;       /* Nothing to write. */
1169
1170         transfer_debug("%s is writable", t->dest_name);
1171         bytes = xwrite(t->dest, t->buf, t->bufuse);
1172         if (bytes < 0 && errno != EWOULDBLOCK) {
1173                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1174                 return -1;
1175         } else if (bytes > 0) {
1176                 t->bufuse -= bytes;
1177                 if (t->bufuse)
1178                         memmove(t->buf, t->buf + bytes, t->bufuse);
1179                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1180                         (int)bytes, t->dest_name, (int)t->bufuse);
1181         }
1182         return 0;
1183 }
1184
1185
1186 /* State of bidirectional transfer loop. */
1187 struct bidirectional_transfer_state {
1188         /* Direction from program to git. */
1189         struct unidirectional_transfer ptg;
1190         /* Direction from git to program. */
1191         struct unidirectional_transfer gtp;
1192 };
1193
1194 static void *udt_copy_task_routine(void *udt)
1195 {
1196         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1197         while (t->state != SSTATE_FINISHED) {
1198                 if (STATE_NEEDS_READING(t->state))
1199                         if (udt_do_read(t))
1200                                 return NULL;
1201                 if (STATE_NEEDS_WRITING(t->state))
1202                         if (udt_do_write(t))
1203                                 return NULL;
1204                 if (STATE_NEEDS_CLOSING(t->state))
1205                         udt_close_if_finished(t);
1206         }
1207         return udt;     /* Just some non-NULL value. */
1208 }
1209
1210 #ifndef NO_PTHREADS
1211
1212 /*
1213  * Join thread, with appropriate errors on failure. Name is name for the
1214  * thread (for error messages). Returns 0 on success, 1 on failure.
1215  */
1216 static int tloop_join(pthread_t thread, const char *name)
1217 {
1218         int err;
1219         void *tret;
1220         err = pthread_join(thread, &tret);
1221         if (!tret) {
1222                 error("%s thread failed", name);
1223                 return 1;
1224         }
1225         if (err) {
1226                 error("%s thread failed to join: %s", name, strerror(err));
1227                 return 1;
1228         }
1229         return 0;
1230 }
1231
1232 /*
1233  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1234  * -1 on failure.
1235  */
1236 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1237 {
1238         pthread_t gtp_thread;
1239         pthread_t ptg_thread;
1240         int err;
1241         int ret = 0;
1242         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1243                 &s->gtp);
1244         if (err)
1245                 die("Can't start thread for copying data: %s", strerror(err));
1246         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1247                 &s->ptg);
1248         if (err)
1249                 die("Can't start thread for copying data: %s", strerror(err));
1250
1251         ret |= tloop_join(gtp_thread, "Git to program copy");
1252         ret |= tloop_join(ptg_thread, "Program to git copy");
1253         return ret;
1254 }
1255 #else
1256
1257 /* Close the source and target (for writing) for transfer. */
1258 static void udt_kill_transfer(struct unidirectional_transfer *t)
1259 {
1260         t->state = SSTATE_FINISHED;
1261         /*
1262          * Socket read end left open isn't a disaster if nobody
1263          * attempts to read from it (mingw compat headers do not
1264          * have SHUT_RD)...
1265          *
1266          * We can't fully close the socket since otherwise gtp
1267          * task would first close the socket it sends data to
1268          * while closing the ptg file descriptors.
1269          */
1270         if (!t->src_is_sock)
1271                 close(t->src);
1272         if (t->dest_is_sock)
1273                 shutdown(t->dest, SHUT_WR);
1274         else
1275                 close(t->dest);
1276 }
1277
1278 /*
1279  * Join process, with appropriate errors on failure. Name is name for the
1280  * process (for error messages). Returns 0 on success, 1 on failure.
1281  */
1282 static int tloop_join(pid_t pid, const char *name)
1283 {
1284         int tret;
1285         if (waitpid(pid, &tret, 0) < 0) {
1286                 error("%s process failed to wait: %s", name, strerror(errno));
1287                 return 1;
1288         }
1289         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1290                 error("%s process failed", name);
1291                 return 1;
1292         }
1293         return 0;
1294 }
1295
1296 /*
1297  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1298  * -1 on failure.
1299  */
1300 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1301 {
1302         pid_t pid1, pid2;
1303         int ret = 0;
1304
1305         /* Fork thread #1: git to program. */
1306         pid1 = fork();
1307         if (pid1 < 0)
1308                 die_errno("Can't start thread for copying data");
1309         else if (pid1 == 0) {
1310                 udt_kill_transfer(&s->ptg);
1311                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1312         }
1313
1314         /* Fork thread #2: program to git. */
1315         pid2 = fork();
1316         if (pid2 < 0)
1317                 die_errno("Can't start thread for copying data");
1318         else if (pid2 == 0) {
1319                 udt_kill_transfer(&s->gtp);
1320                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1321         }
1322
1323         /*
1324          * Close both streams in parent as to not interfere with
1325          * end of file detection and wait for both tasks to finish.
1326          */
1327         udt_kill_transfer(&s->gtp);
1328         udt_kill_transfer(&s->ptg);
1329         ret |= tloop_join(pid1, "Git to program copy");
1330         ret |= tloop_join(pid2, "Program to git copy");
1331         return ret;
1332 }
1333 #endif
1334
1335 /*
1336  * Copies data from stdin to output and from input to stdout simultaneously.
1337  * Additionally filtering through given filter. If filter is NULL, uses
1338  * identity filter.
1339  */
1340 int bidirectional_transfer_loop(int input, int output)
1341 {
1342         struct bidirectional_transfer_state state;
1343
1344         /* Fill the state fields. */
1345         state.ptg.src = input;
1346         state.ptg.dest = 1;
1347         state.ptg.src_is_sock = (input == output);
1348         state.ptg.dest_is_sock = 0;
1349         state.ptg.state = SSTATE_TRANSFERING;
1350         state.ptg.bufuse = 0;
1351         state.ptg.src_name = "remote input";
1352         state.ptg.dest_name = "stdout";
1353
1354         state.gtp.src = 0;
1355         state.gtp.dest = output;
1356         state.gtp.src_is_sock = 0;
1357         state.gtp.dest_is_sock = (input == output);
1358         state.gtp.state = SSTATE_TRANSFERING;
1359         state.gtp.bufuse = 0;
1360         state.gtp.src_name = "stdin";
1361         state.gtp.dest_name = "remote output";
1362
1363         return tloop_spawnwait_tasks(&state);
1364 }