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                 exit(128);
  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 xchgline(struct helper_data *helper, struct strbuf *buffer)
  75 {
  76         sendline(helper, buffer);
  77         recvline(helper, buffer);
  78 }
  79
  80 static void write_constant(int fd, const char *str)
  81 {
  82         if (debug)
  83                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  84         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  85                 die_errno("Full write to remote helper failed");
  86 }
  87
  88 static const char *remove_ext_force(const char *url)
  89 {
  90         if (url) {
  91                 const char *colon = strchr(url, ':');
  92                 if (colon && colon[1] == ':')
  93                         return colon + 2;
  94         }
  95         return url;
  96 }
  97
  98 static void do_take_over(struct transport *transport)
  99 {
 100         struct helper_data *data;
 101         data = (struct helper_data *)transport->data;
 102         transport_take_over(transport, data->helper);
 103         fclose(data->out);
 104         free(data);
 105 }
 106
 107 static struct child_process *get_helper(struct transport *transport)
 108 {
 109         struct helper_data *data = transport->data;
 110         struct argv_array argv = ARGV_ARRAY_INIT;
 111         struct strbuf buf = STRBUF_INIT;
 112         struct child_process *helper;
 113         const char **refspecs = NULL;
 114         int refspec_nr = 0;
 115         int refspec_alloc = 0;
 116         int duped;
 117         int code;
 118         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 119         const char *helper_env[] = {
 120                 git_dir_buf,
 121                 NULL
 122         };
 123
 124
 125         if (data->helper)
 126                 return data->helper;
 127
 128         helper = xcalloc(1, sizeof(*helper));
 129         helper->in = -1;
 130         helper->out = -1;
 131         helper->err = 0;
 132         argv_array_pushf(&argv, "git-remote-%s", data->name);
 133         argv_array_push(&argv, transport->remote->name);
 134         argv_array_push(&argv, remove_ext_force(transport->url));
 135         helper->argv = argv_array_detach(&argv, NULL);
 136         helper->git_cmd = 0;
 137         helper->silent_exec_failure = 1;
 138
 139         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 140         helper->env = helper_env;
 141
 142         code = start_command(helper);
 143         if (code < 0 && errno == ENOENT)
 144                 die("Unable to find remote helper for '%s'", data->name);
 145         else if (code != 0)
 146                 exit(code);
 147
 148         data->helper = helper;
 149         data->no_disconnect_req = 0;
 150
 151         /*
 152          * Open the output as FILE* so strbuf_getline() can be used.
 153          * Do this with duped fd because fclose() will close the fd,
 154          * and stuff like taking over will require the fd to remain.
 155          */
 156         duped = dup(helper->out);
 157         if (duped < 0)
 158                 die_errno("Can't dup helper output fd");
 159         data->out = xfdopen(duped, "r");
 160
 161         write_constant(helper->in, "capabilities\n");
 162
 163         while (1) {
 164                 const char *capname;
 165                 int mandatory = 0;
 166                 recvline(data, &buf);
 167
 168                 if (!*buf.buf)
 169                         break;
 170
 171                 if (*buf.buf == '*') {
 172                         capname = buf.buf + 1;
 173                         mandatory = 1;
 174                 } else
 175                         capname = buf.buf;
 176
 177                 if (debug)
 178                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 179                 if (!strcmp(capname, "fetch"))
 180                         data->fetch = 1;
 181                 else if (!strcmp(capname, "option"))
 182                         data->option = 1;
 183                 else if (!strcmp(capname, "push"))
 184                         data->push = 1;
 185                 else if (!strcmp(capname, "import"))
 186                         data->import = 1;
 187                 else if (!strcmp(capname, "bidi-import"))
 188                         data->bidi_import = 1;
 189                 else if (!strcmp(capname, "export"))
 190                         data->export = 1;
 191                 else if (!strcmp(capname, "check-connectivity"))
 192                         data->check_connectivity = 1;
 193                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 194                         ALLOC_GROW(refspecs,
 195                                    refspec_nr + 1,
 196                                    refspec_alloc);
 197                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 198                 } else if (!strcmp(capname, "connect")) {
 199                         data->connect = 1;
 200                 } else if (!strcmp(capname, "signed-tags")) {
 201                         data->signed_tags = 1;
 202                 } else if (!prefixcmp(capname, "export-marks ")) {
 203                         struct strbuf arg = STRBUF_INIT;
 204                         strbuf_addstr(&arg, "--export-marks=");
 205                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 206                         data->export_marks = strbuf_detach(&arg, NULL);
 207                 } else if (!prefixcmp(capname, "import-marks")) {
 208                         struct strbuf arg = STRBUF_INIT;
 209                         strbuf_addstr(&arg, "--import-marks=");
 210                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 211                         data->import_marks = strbuf_detach(&arg, NULL);
 212                 } else if (!prefixcmp(capname, "no-private-update")) {
 213                         data->no_private_update = 1;
 214                 } else if (mandatory) {
 215                         die("Unknown mandatory capability %s. This remote "
 216                             "helper probably needs newer version of Git.",
 217                             capname);
 218                 }
 219         }
 220         if (refspecs) {
 221                 int i;
 222                 data->refspec_nr = refspec_nr;
 223                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 224                 for (i = 0; i < refspec_nr; i++)
 225                         free((char *)refspecs[i]);
 226                 free(refspecs);
 227         } else if (data->import || data->bidi_import || data->export) {
 228                 warning("This remote helper should implement refspec capability.");
 229         }
 230         strbuf_release(&buf);
 231         if (debug)
 232                 fprintf(stderr, "Debug: Capabilities complete.\n");
 233         return data->helper;
 234 }
 235
 236 static int disconnect_helper(struct transport *transport)
 237 {
 238         struct helper_data *data = transport->data;
 239         int res = 0;
 240
 241         if (data->helper) {
 242                 if (debug)
 243                         fprintf(stderr, "Debug: Disconnecting.\n");
 244                 if (!data->no_disconnect_req) {
 245                         /*
 246                          * Ignore write errors; there's nothing we can do,
 247                          * since we're about to close the pipe anyway. And the
 248                          * most likely error is EPIPE due to the helper dying
 249                          * to report an error itself.
 250                          */
 251                         sigchain_push(SIGPIPE, SIG_IGN);
 252                         xwrite(data->helper->in, "\n", 1);
 253                         sigchain_pop(SIGPIPE);
 254                 }
 255                 close(data->helper->in);
 256                 close(data->helper->out);
 257                 fclose(data->out);
 258                 res = finish_command(data->helper);
 259                 argv_array_free_detached(data->helper->argv);
 260                 free(data->helper);
 261                 data->helper = NULL;
 262         }
 263         return res;
 264 }
 265
 266 static const char *unsupported_options[] = {
 267         TRANS_OPT_UPLOADPACK,
 268         TRANS_OPT_RECEIVEPACK,
 269         TRANS_OPT_THIN,
 270         TRANS_OPT_KEEP
 271         };
 272 static const char *boolean_options[] = {
 273         TRANS_OPT_THIN,
 274         TRANS_OPT_KEEP,
 275         TRANS_OPT_FOLLOWTAGS
 276         };
 277
 278 static int set_helper_option(struct transport *transport,
 279                           const char *name, const char *value)
 280 {
 281         struct helper_data *data = transport->data;
 282         struct strbuf buf = STRBUF_INIT;
 283         int i, ret, is_bool = 0;
 284
 285         get_helper(transport);
 286
 287         if (!data->option)
 288                 return 1;
 289
 290         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 291                 if (!strcmp(name, unsupported_options[i]))
 292                         return 1;
 293         }
 294
 295         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 296                 if (!strcmp(name, boolean_options[i])) {
 297                         is_bool = 1;
 298                         break;
 299                 }
 300         }
 301
 302         strbuf_addf(&buf, "option %s ", name);
 303         if (is_bool)
 304                 strbuf_addstr(&buf, value ? "true" : "false");
 305         else
 306                 quote_c_style(value, &buf, NULL, 0);
 307         strbuf_addch(&buf, '\n');
 308
 309         xchgline(data, &buf);
 310
 311         if (!strcmp(buf.buf, "ok"))
 312                 ret = 0;
 313         else if (!prefixcmp(buf.buf, "error")) {
 314                 ret = -1;
 315         } else if (!strcmp(buf.buf, "unsupported"))
 316                 ret = 1;
 317         else {
 318                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 319                 ret = 1;
 320         }
 321         strbuf_release(&buf);
 322         return ret;
 323 }
 324
 325 static void standard_options(struct transport *t)
 326 {
 327         char buf[16];
 328         int n;
 329         int v = t->verbose;
 330
 331         set_helper_option(t, "progress", t->progress ? "true" : "false");
 332
 333         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 334         if (n >= sizeof(buf))
 335                 die("impossibly large verbosity value");
 336         set_helper_option(t, "verbosity", buf);
 337 }
 338
 339 static int release_helper(struct transport *transport)
 340 {
 341         int res = 0;
 342         struct helper_data *data = transport->data;
 343         free_refspec(data->refspec_nr, data->refspecs);
 344         data->refspecs = NULL;
 345         res = disconnect_helper(transport);
 346         free(transport->data);
 347         return res;
 348 }
 349
 350 static int fetch_with_fetch(struct transport *transport,
 351                             int nr_heads, struct ref **to_fetch)
 352 {
 353         struct helper_data *data = transport->data;
 354         int i;
 355         struct strbuf buf = STRBUF_INIT;
 356
 357         standard_options(transport);
 358         if (data->check_connectivity &&
 359             data->transport_options.check_self_contained_and_connected)
 360                 set_helper_option(transport, "check-connectivity", "true");
 361
 362         for (i = 0; i < nr_heads; i++) {
 363                 const struct ref *posn = to_fetch[i];
 364                 if (posn->status & REF_STATUS_UPTODATE)
 365                         continue;
 366
 367                 strbuf_addf(&buf, "fetch %s %s\n",
 368                             sha1_to_hex(posn->old_sha1), posn->name);
 369         }
 370
 371         strbuf_addch(&buf, '\n');
 372         sendline(data, &buf);
 373
 374         while (1) {
 375                 recvline(data, &buf);
 376
 377                 if (!prefixcmp(buf.buf, "lock ")) {
 378                         const char *name = buf.buf + 5;
 379                         if (transport->pack_lockfile)
 380                                 warning("%s also locked %s", data->name, name);
 381                         else
 382                                 transport->pack_lockfile = xstrdup(name);
 383                 }
 384                 else if (data->check_connectivity &&
 385                          data->transport_options.check_self_contained_and_connected &&
 386                          !strcmp(buf.buf, "connectivity-ok"))
 387                         data->transport_options.self_contained_and_connected = 1;
 388                 else if (!buf.len)
 389                         break;
 390                 else
 391                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 392         }
 393         strbuf_release(&buf);
 394         return 0;
 395 }
 396
 397 static int get_importer(struct transport *transport, struct child_process *fastimport)
 398 {
 399         struct child_process *helper = get_helper(transport);
 400         struct helper_data *data = transport->data;
 401         struct argv_array argv = ARGV_ARRAY_INIT;
 402         int cat_blob_fd, code;
 403         memset(fastimport, 0, sizeof(*fastimport));
 404         fastimport->in = helper->out;
 405         argv_array_push(&argv, "fast-import");
 406         argv_array_push(&argv, debug ? "--stats" : "--quiet");
 407
 408         if (data->bidi_import) {
 409                 cat_blob_fd = xdup(helper->in);
 410                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 411         }
 412         fastimport->argv = argv.argv;
 413         fastimport->git_cmd = 1;
 414
 415         code = start_command(fastimport);
 416         return code;
 417 }
 418
 419 static int get_exporter(struct transport *transport,
 420                         struct child_process *fastexport,
 421                         struct string_list *revlist_args)
 422 {
 423         struct helper_data *data = transport->data;
 424         struct child_process *helper = get_helper(transport);
 425         int argc = 0, i;
 426         memset(fastexport, 0, sizeof(*fastexport));
 427
 428         /* we need to duplicate helper->in because we want to use it after
 429          * fastexport is done with it. */
 430         fastexport->out = dup(helper->in);
 431         fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
 432         fastexport->argv[argc++] = "fast-export";
 433         fastexport->argv[argc++] = "--use-done-feature";
 434         fastexport->argv[argc++] = data->signed_tags ?
 435                 "--signed-tags=verbatim" : "--signed-tags=warn-strip";
 436         if (data->export_marks)
 437                 fastexport->argv[argc++] = data->export_marks;
 438         if (data->import_marks)
 439                 fastexport->argv[argc++] = data->import_marks;
 440
 441         for (i = 0; i < revlist_args->nr; i++)
 442                 fastexport->argv[argc++] = revlist_args->items[i].string;
 443
 444         fastexport->git_cmd = 1;
 445         return start_command(fastexport);
 446 }
 447
 448 static int fetch_with_import(struct transport *transport,
 449                              int nr_heads, struct ref **to_fetch)
 450 {
 451         struct child_process fastimport;
 452         struct helper_data *data = transport->data;
 453         int i;
 454         struct ref *posn;
 455         struct strbuf buf = STRBUF_INIT;
 456
 457         get_helper(transport);
 458
 459         if (get_importer(transport, &fastimport))
 460                 die("Couldn't run fast-import");
 461
 462         for (i = 0; i < nr_heads; i++) {
 463                 posn = to_fetch[i];
 464                 if (posn->status & REF_STATUS_UPTODATE)
 465                         continue;
 466
 467                 strbuf_addf(&buf, "import %s\n", posn->name);
 468                 sendline(data, &buf);
 469                 strbuf_reset(&buf);
 470         }
 471
 472         write_constant(data->helper->in, "\n");
 473         /*
 474          * remote-helpers that advertise the bidi-import capability are required to
 475          * buffer the complete batch of import commands until this newline before
 476          * sending data to fast-import.
 477          * These helpers read back data from fast-import on their stdin, which could
 478          * be mixed with import commands, otherwise.
 479          */
 480
 481         if (finish_command(&fastimport))
 482                 die("Error while running fast-import");
 483         argv_array_free_detached(fastimport.argv);
 484
 485         /*
 486          * The fast-import stream of a remote helper that advertises
 487          * the "refspec" capability writes to the refs named after the
 488          * right hand side of the first refspec matching each ref we
 489          * were fetching.
 490          *
 491          * (If no "refspec" capability was specified, for historical
 492          * reasons we default to the equivalent of *:*.)
 493          *
 494          * Store the result in to_fetch[i].old_sha1.  Callers such
 495          * as "git fetch" can use the value to write feedback to the
 496          * terminal, populate FETCH_HEAD, and determine what new value
 497          * should be written to peer_ref if the update is a
 498          * fast-forward or this is a forced update.
 499          */
 500         for (i = 0; i < nr_heads; i++) {
 501                 char *private;
 502                 posn = to_fetch[i];
 503                 if (posn->status & REF_STATUS_UPTODATE)
 504                         continue;
 505                 if (data->refspecs)
 506                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 507                 else
 508                         private = xstrdup(posn->name);
 509                 if (private) {
 510                         read_ref(private, posn->old_sha1);
 511                         free(private);
 512                 }
 513         }
 514         strbuf_release(&buf);
 515         return 0;
 516 }
 517
 518 static int process_connect_service(struct transport *transport,
 519                                    const char *name, const char *exec)
 520 {
 521         struct helper_data *data = transport->data;
 522         struct strbuf cmdbuf = STRBUF_INIT;
 523         struct child_process *helper;
 524         int r, duped, ret = 0;
 525         FILE *input;
 526
 527         helper = get_helper(transport);
 528
 529         /*
 530          * Yes, dup the pipe another time, as we need unbuffered version
 531          * of input pipe as FILE*. fclose() closes the underlying fd and
 532          * stream buffering only can be changed before first I/O operation
 533          * on it.
 534          */
 535         duped = dup(helper->out);
 536         if (duped < 0)
 537                 die_errno("Can't dup helper output fd");
 538         input = xfdopen(duped, "r");
 539         setvbuf(input, NULL, _IONBF, 0);
 540
 541         /*
 542          * Handle --upload-pack and friends. This is fire and forget...
 543          * just warn if it fails.
 544          */
 545         if (strcmp(name, exec)) {
 546                 r = set_helper_option(transport, "servpath", exec);
 547                 if (r > 0)
 548                         warning("Setting remote service path not supported by protocol.");
 549                 else if (r < 0)
 550                         warning("Invalid remote service path.");
 551         }
 552
 553         if (data->connect)
 554                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 555         else
 556                 goto exit;
 557
 558         sendline(data, &cmdbuf);
 559         recvline_fh(input, &cmdbuf, name);
 560         if (!strcmp(cmdbuf.buf, "")) {
 561                 data->no_disconnect_req = 1;
 562                 if (debug)
 563                         fprintf(stderr, "Debug: Smart transport connection "
 564                                 "ready.\n");
 565                 ret = 1;
 566         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 567                 if (debug)
 568                         fprintf(stderr, "Debug: Falling back to dumb "
 569                                 "transport.\n");
 570         } else
 571                 die("Unknown response to connect: %s",
 572                         cmdbuf.buf);
 573
 574 exit:
 575         fclose(input);
 576         return ret;
 577 }
 578
 579 static int process_connect(struct transport *transport,
 580                                      int for_push)
 581 {
 582         struct helper_data *data = transport->data;
 583         const char *name;
 584         const char *exec;
 585
 586         name = for_push ? "git-receive-pack" : "git-upload-pack";
 587         if (for_push)
 588                 exec = data->transport_options.receivepack;
 589         else
 590                 exec = data->transport_options.uploadpack;
 591
 592         return process_connect_service(transport, name, exec);
 593 }
 594
 595 static int connect_helper(struct transport *transport, const char *name,
 596                    const char *exec, int fd[2])
 597 {
 598         struct helper_data *data = transport->data;
 599
 600         /* Get_helper so connect is inited. */
 601         get_helper(transport);
 602         if (!data->connect)
 603                 die("Operation not supported by protocol.");
 604
 605         if (!process_connect_service(transport, name, exec))
 606                 die("Can't connect to subservice %s.", name);
 607
 608         fd[0] = data->helper->out;
 609         fd[1] = data->helper->in;
 610         return 0;
 611 }
 612
 613 static int fetch(struct transport *transport,
 614                  int nr_heads, struct ref **to_fetch)
 615 {
 616         struct helper_data *data = transport->data;
 617         int i, count;
 618
 619         if (process_connect(transport, 0)) {
 620                 do_take_over(transport);
 621                 return transport->fetch(transport, nr_heads, to_fetch);
 622         }
 623
 624         count = 0;
 625         for (i = 0; i < nr_heads; i++)
 626                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 627                         count++;
 628
 629         if (!count)
 630                 return 0;
 631
 632         if (data->fetch)
 633                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 634
 635         if (data->import)
 636                 return fetch_with_import(transport, nr_heads, to_fetch);
 637
 638         return -1;
 639 }
 640
 641 static int push_update_ref_status(struct strbuf *buf,
 642                                    struct ref **ref,
 643                                    struct ref *remote_refs)
 644 {
 645         char *refname, *msg;
 646         int status;
 647
 648         if (!prefixcmp(buf->buf, "ok ")) {
 649                 status = REF_STATUS_OK;
 650                 refname = buf->buf + 3;
 651         } else if (!prefixcmp(buf->buf, "error ")) {
 652                 status = REF_STATUS_REMOTE_REJECT;
 653                 refname = buf->buf + 6;
 654         } else
 655                 die("expected ok/error, helper said '%s'", buf->buf);
 656
 657         msg = strchr(refname, ' ');
 658         if (msg) {
 659                 struct strbuf msg_buf = STRBUF_INIT;
 660                 const char *end;
 661
 662                 *msg++ = '\0';
 663                 if (!unquote_c_style(&msg_buf, msg, &end))
 664                         msg = strbuf_detach(&msg_buf, NULL);
 665                 else
 666                         msg = xstrdup(msg);
 667                 strbuf_release(&msg_buf);
 668
 669                 if (!strcmp(msg, "no match")) {
 670                         status = REF_STATUS_NONE;
 671                         free(msg);
 672                         msg = NULL;
 673                 }
 674                 else if (!strcmp(msg, "up to date")) {
 675                         status = REF_STATUS_UPTODATE;
 676                         free(msg);
 677                         msg = NULL;
 678                 }
 679                 else if (!strcmp(msg, "non-fast forward")) {
 680                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 681                         free(msg);
 682                         msg = NULL;
 683                 }
 684                 else if (!strcmp(msg, "already exists")) {
 685                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 686                         free(msg);
 687                         msg = NULL;
 688                 }
 689                 else if (!strcmp(msg, "fetch first")) {
 690                         status = REF_STATUS_REJECT_FETCH_FIRST;
 691                         free(msg);
 692                         msg = NULL;
 693                 }
 694                 else if (!strcmp(msg, "needs force")) {
 695                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 696                         free(msg);
 697                         msg = NULL;
 698                 }
 699                 else if (!strcmp(msg, "stale info")) {
 700                         status = REF_STATUS_REJECT_STALE;
 701                         free(msg);
 702                         msg = NULL;
 703                 }
 704         }
 705
 706         if (*ref)
 707                 *ref = find_ref_by_name(*ref, refname);
 708         if (!*ref)
 709                 *ref = find_ref_by_name(remote_refs, refname);
 710         if (!*ref) {
 711                 warning("helper reported unexpected status of %s", refname);
 712                 return 1;
 713         }
 714
 715         if ((*ref)->status != REF_STATUS_NONE) {
 716                 /*
 717                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 718                  * status reported by the remote helper if the latter is 'no match'.
 719                  */
 720                 if (status == REF_STATUS_NONE)
 721                         return 1;
 722         }
 723
 724         (*ref)->status = status;
 725         (*ref)->remote_status = msg;
 726         return !(status == REF_STATUS_OK);
 727 }
 728
 729 static void push_update_refs_status(struct helper_data *data,
 730                                     struct ref *remote_refs)
 731 {
 732         struct strbuf buf = STRBUF_INIT;
 733         struct ref *ref = remote_refs;
 734         for (;;) {
 735                 char *private;
 736
 737                 recvline(data, &buf);
 738                 if (!buf.len)
 739                         break;
 740
 741                 if (push_update_ref_status(&buf, &ref, remote_refs))
 742                         continue;
 743
 744                 if (!data->refspecs || data->no_private_update)
 745                         continue;
 746
 747                 /* propagate back the update to the remote namespace */
 748                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 749                 if (!private)
 750                         continue;
 751                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 752                 free(private);
 753         }
 754         strbuf_release(&buf);
 755 }
 756
 757 static int push_refs_with_push(struct transport *transport,
 758                                struct ref *remote_refs, int flags)
 759 {
 760         int force_all = flags & TRANSPORT_PUSH_FORCE;
 761         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 762         struct helper_data *data = transport->data;
 763         struct strbuf buf = STRBUF_INIT;
 764         struct ref *ref;
 765         struct string_list cas_options = STRING_LIST_INIT_DUP;
 766         struct string_list_item *cas_option;
 767
 768         get_helper(transport);
 769         if (!data->push)
 770                 return 1;
 771
 772         for (ref = remote_refs; ref; ref = ref->next) {
 773                 if (!ref->peer_ref && !mirror)
 774                         continue;
 775
 776                 /* Check for statuses set by set_ref_status_for_push() */
 777                 switch (ref->status) {
 778                 case REF_STATUS_REJECT_NONFASTFORWARD:
 779                 case REF_STATUS_REJECT_STALE:
 780                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 781                 case REF_STATUS_UPTODATE:
 782                         continue;
 783                 default:
 784                         ; /* do nothing */
 785                 }
 786
 787                 if (force_all)
 788                         ref->force = 1;
 789
 790                 strbuf_addstr(&buf, "push ");
 791                 if (!ref->deletion) {
 792                         if (ref->force)
 793                                 strbuf_addch(&buf, '+');
 794                         if (ref->peer_ref)
 795                                 strbuf_addstr(&buf, ref->peer_ref->name);
 796                         else
 797                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 798                 }
 799                 strbuf_addch(&buf, ':');
 800                 strbuf_addstr(&buf, ref->name);
 801                 strbuf_addch(&buf, '\n');
 802
 803                 /*
 804                  * The "--force-with-lease" options without explicit
 805                  * values to expect have already been expanded into
 806                  * the ref->old_sha1_expect[] field; we can ignore
 807                  * transport->smart_options->cas altogether and instead
 808                  * can enumerate them from the refs.
 809                  */
 810                 if (ref->expect_old_sha1) {
 811                         struct strbuf cas = STRBUF_INIT;
 812                         strbuf_addf(&cas, "%s:%s",
 813                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 814                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 815                 }
 816         }
 817         if (buf.len == 0) {
 818                 string_list_clear(&cas_options, 0);
 819                 return 0;
 820         }
 821
 822         standard_options(transport);
 823         for_each_string_list_item(cas_option, &cas_options)
 824                 set_helper_option(transport, "cas", cas_option->string);
 825
 826         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 827                 if (set_helper_option(transport, "dry-run", "true") != 0)
 828                         die("helper %s does not support dry-run", data->name);
 829         }
 830
 831         strbuf_addch(&buf, '\n');
 832         sendline(data, &buf);
 833         strbuf_release(&buf);
 834
 835         push_update_refs_status(data, remote_refs);
 836         return 0;
 837 }
 838
 839 static int push_refs_with_export(struct transport *transport,
 840                 struct ref *remote_refs, int flags)
 841 {
 842         struct ref *ref;
 843         struct child_process *helper, exporter;
 844         struct helper_data *data = transport->data;
 845         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 846         struct strbuf buf = STRBUF_INIT;
 847
 848         if (!data->refspecs)
 849                 die("remote-helper doesn't support push; refspec needed");
 850
 851         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 852                 if (set_helper_option(transport, "dry-run", "true") != 0)
 853                         die("helper %s does not support dry-run", data->name);
 854         }
 855
 856         helper = get_helper(transport);
 857
 858         write_constant(helper->in, "export\n");
 859
 860         strbuf_reset(&buf);
 861
 862         for (ref = remote_refs; ref; ref = ref->next) {
 863                 char *private;
 864                 unsigned char sha1[20];
 865
 866                 if (ref->deletion)
 867                         die("remote-helpers do not support ref deletion");
 868
 869                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 870                 if (private && !get_sha1(private, sha1)) {
 871                         strbuf_addf(&buf, "^%s", private);
 872                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 873                         hashcpy(ref->old_sha1, sha1);
 874                 }
 875                 free(private);
 876
 877                 if (ref->deletion)
 878                         die("remote-helpers do not support ref deletion");
 879
 880                 if (ref->peer_ref) {
 881                         if (strcmp(ref->peer_ref->name, ref->name))
 882                                 die("remote-helpers do not support old:new syntax");
 883                         string_list_append(&revlist_args, ref->peer_ref->name);
 884                 }
 885         }
 886
 887         if (get_exporter(transport, &exporter, &revlist_args))
 888                 die("Couldn't run fast-export");
 889
 890         if (finish_command(&exporter))
 891                 die("Error while running fast-export");
 892         push_update_refs_status(data, remote_refs);
 893         return 0;
 894 }
 895
 896 static int push_refs(struct transport *transport,
 897                 struct ref *remote_refs, int flags)
 898 {
 899         struct helper_data *data = transport->data;
 900
 901         if (process_connect(transport, 1)) {
 902                 do_take_over(transport);
 903                 return transport->push_refs(transport, remote_refs, flags);
 904         }
 905
 906         if (!remote_refs) {
 907                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 908                         "Perhaps you should specify a branch such as 'master'.\n");
 909                 return 0;
 910         }
 911
 912         if (data->push)
 913                 return push_refs_with_push(transport, remote_refs, flags);
 914
 915         if (data->export)
 916                 return push_refs_with_export(transport, remote_refs, flags);
 917
 918         return -1;
 919 }
 920
 921
 922 static int has_attribute(const char *attrs, const char *attr) {
 923         int len;
 924         if (!attrs)
 925                 return 0;
 926
 927         len = strlen(attr);
 928         for (;;) {
 929                 const char *space = strchrnul(attrs, ' ');
 930                 if (len == space - attrs && !strncmp(attrs, attr, len))
 931                         return 1;
 932                 if (!*space)
 933                         return 0;
 934                 attrs = space + 1;
 935         }
 936 }
 937
 938 static struct ref *get_refs_list(struct transport *transport, int for_push)
 939 {
 940         struct helper_data *data = transport->data;
 941         struct child_process *helper;
 942         struct ref *ret = NULL;
 943         struct ref **tail = &ret;
 944         struct ref *posn;
 945         struct strbuf buf = STRBUF_INIT;
 946
 947         helper = get_helper(transport);
 948
 949         if (process_connect(transport, for_push)) {
 950                 do_take_over(transport);
 951                 return transport->get_refs_list(transport, for_push);
 952         }
 953
 954         if (data->push && for_push)
 955                 write_str_in_full(helper->in, "list for-push\n");
 956         else
 957                 write_str_in_full(helper->in, "list\n");
 958
 959         while (1) {
 960                 char *eov, *eon;
 961                 recvline(data, &buf);
 962
 963                 if (!*buf.buf)
 964                         break;
 965
 966                 eov = strchr(buf.buf, ' ');
 967                 if (!eov)
 968                         die("Malformed response in ref list: %s", buf.buf);
 969                 eon = strchr(eov + 1, ' ');
 970                 *eov = '\0';
 971                 if (eon)
 972                         *eon = '\0';
 973                 *tail = alloc_ref(eov + 1);
 974                 if (buf.buf[0] == '@')
 975                         (*tail)->symref = xstrdup(buf.buf + 1);
 976                 else if (buf.buf[0] != '?')
 977                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 978                 if (eon) {
 979                         if (has_attribute(eon + 1, "unchanged")) {
 980                                 (*tail)->status |= REF_STATUS_UPTODATE;
 981                                 read_ref((*tail)->name, (*tail)->old_sha1);
 982                         }
 983                 }
 984                 tail = &((*tail)->next);
 985         }
 986         if (debug)
 987                 fprintf(stderr, "Debug: Read ref listing.\n");
 988         strbuf_release(&buf);
 989
 990         for (posn = ret; posn; posn = posn->next)
 991                 resolve_remote_symref(posn, ret);
 992
 993         return ret;
 994 }
 995
 996 int transport_helper_init(struct transport *transport, const char *name)
 997 {
 998         struct helper_data *data = xcalloc(sizeof(*data), 1);
 999         data->name = name;
1000
1001         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1002                 debug = 1;
1003
1004         transport->data = data;
1005         transport->set_option = set_helper_option;
1006         transport->get_refs_list = get_refs_list;
1007         transport->fetch = fetch;
1008         transport->push_refs = push_refs;
1009         transport->disconnect = release_helper;
1010         transport->connect = connect_helper;
1011         transport->smart_options = &(data->transport_options);
1012         return 0;
1013 }
1014
1015 /*
1016  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1017  * buffer less), so attempt reads and writes with up to that size.
1018  */
1019 #define BUFFERSIZE 65536
1020 /* This should be enough to hold debugging message. */
1021 #define PBUFFERSIZE 8192
1022
1023 /* Print bidirectional transfer loop debug message. */
1024 __attribute__((format (printf, 1, 2)))
1025 static void transfer_debug(const char *fmt, ...)
1026 {
1027         va_list args;
1028         char msgbuf[PBUFFERSIZE];
1029         static int debug_enabled = -1;
1030
1031         if (debug_enabled < 0)
1032                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1033         if (!debug_enabled)
1034                 return;
1035
1036         va_start(args, fmt);
1037         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1038         va_end(args);
1039         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1040 }
1041
1042 /* Stream state: More data may be coming in this direction. */
1043 #define SSTATE_TRANSFERING 0
1044 /*
1045  * Stream state: No more data coming in this direction, flushing rest of
1046  * data.
1047  */
1048 #define SSTATE_FLUSHING 1
1049 /* Stream state: Transfer in this direction finished. */
1050 #define SSTATE_FINISHED 2
1051
1052 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1053 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1054 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1055
1056 /* Unidirectional transfer. */
1057 struct unidirectional_transfer {
1058         /* Source */
1059         int src;
1060         /* Destination */
1061         int dest;
1062         /* Is source socket? */
1063         int src_is_sock;
1064         /* Is destination socket? */
1065         int dest_is_sock;
1066         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1067         int state;
1068         /* Buffer. */
1069         char buf[BUFFERSIZE];
1070         /* Buffer used. */
1071         size_t bufuse;
1072         /* Name of source. */
1073         const char *src_name;
1074         /* Name of destination. */
1075         const char *dest_name;
1076 };
1077
1078 /* Closes the target (for writing) if transfer has finished. */
1079 static void udt_close_if_finished(struct unidirectional_transfer *t)
1080 {
1081         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1082                 t->state = SSTATE_FINISHED;
1083                 if (t->dest_is_sock)
1084                         shutdown(t->dest, SHUT_WR);
1085                 else
1086                         close(t->dest);
1087                 transfer_debug("Closed %s.", t->dest_name);
1088         }
1089 }
1090
1091 /*
1092  * Tries to read read data from source into buffer. If buffer is full,
1093  * no data is read. Returns 0 on success, -1 on error.
1094  */
1095 static int udt_do_read(struct unidirectional_transfer *t)
1096 {
1097         ssize_t bytes;
1098
1099         if (t->bufuse == BUFFERSIZE)
1100                 return 0;       /* No space for more. */
1101
1102         transfer_debug("%s is readable", t->src_name);
1103         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1104         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1105                 errno != EINTR) {
1106                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1107                 return -1;
1108         } else if (bytes == 0) {
1109                 transfer_debug("%s EOF (with %i bytes in buffer)",
1110                         t->src_name, (int)t->bufuse);
1111                 t->state = SSTATE_FLUSHING;
1112         } else if (bytes > 0) {
1113                 t->bufuse += bytes;
1114                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1115                         (int)bytes, t->src_name, (int)t->bufuse);
1116         }
1117         return 0;
1118 }
1119
1120 /* Tries to write data from buffer into destination. If buffer is empty,
1121  * no data is written. Returns 0 on success, -1 on error.
1122  */
1123 static int udt_do_write(struct unidirectional_transfer *t)
1124 {
1125         ssize_t bytes;
1126
1127         if (t->bufuse == 0)
1128                 return 0;       /* Nothing to write. */
1129
1130         transfer_debug("%s is writable", t->dest_name);
1131         bytes = write(t->dest, t->buf, t->bufuse);
1132         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1133                 errno != EINTR) {
1134                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1135                 return -1;
1136         } else if (bytes > 0) {
1137                 t->bufuse -= bytes;
1138                 if (t->bufuse)
1139                         memmove(t->buf, t->buf + bytes, t->bufuse);
1140                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1141                         (int)bytes, t->dest_name, (int)t->bufuse);
1142         }
1143         return 0;
1144 }
1145
1146
1147 /* State of bidirectional transfer loop. */
1148 struct bidirectional_transfer_state {
1149         /* Direction from program to git. */
1150         struct unidirectional_transfer ptg;
1151         /* Direction from git to program. */
1152         struct unidirectional_transfer gtp;
1153 };
1154
1155 static void *udt_copy_task_routine(void *udt)
1156 {
1157         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1158         while (t->state != SSTATE_FINISHED) {
1159                 if (STATE_NEEDS_READING(t->state))
1160                         if (udt_do_read(t))
1161                                 return NULL;
1162                 if (STATE_NEEDS_WRITING(t->state))
1163                         if (udt_do_write(t))
1164                                 return NULL;
1165                 if (STATE_NEEDS_CLOSING(t->state))
1166                         udt_close_if_finished(t);
1167         }
1168         return udt;     /* Just some non-NULL value. */
1169 }
1170
1171 #ifndef NO_PTHREADS
1172
1173 /*
1174  * Join thread, with appropriate errors on failure. Name is name for the
1175  * thread (for error messages). Returns 0 on success, 1 on failure.
1176  */
1177 static int tloop_join(pthread_t thread, const char *name)
1178 {
1179         int err;
1180         void *tret;
1181         err = pthread_join(thread, &tret);
1182         if (!tret) {
1183                 error("%s thread failed", name);
1184                 return 1;
1185         }
1186         if (err) {
1187                 error("%s thread failed to join: %s", name, strerror(err));
1188                 return 1;
1189         }
1190         return 0;
1191 }
1192
1193 /*
1194  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1195  * -1 on failure.
1196  */
1197 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1198 {
1199         pthread_t gtp_thread;
1200         pthread_t ptg_thread;
1201         int err;
1202         int ret = 0;
1203         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1204                 &s->gtp);
1205         if (err)
1206                 die("Can't start thread for copying data: %s", strerror(err));
1207         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1208                 &s->ptg);
1209         if (err)
1210                 die("Can't start thread for copying data: %s", strerror(err));
1211
1212         ret |= tloop_join(gtp_thread, "Git to program copy");
1213         ret |= tloop_join(ptg_thread, "Program to git copy");
1214         return ret;
1215 }
1216 #else
1217
1218 /* Close the source and target (for writing) for transfer. */
1219 static void udt_kill_transfer(struct unidirectional_transfer *t)
1220 {
1221         t->state = SSTATE_FINISHED;
1222         /*
1223          * Socket read end left open isn't a disaster if nobody
1224          * attempts to read from it (mingw compat headers do not
1225          * have SHUT_RD)...
1226          *
1227          * We can't fully close the socket since otherwise gtp
1228          * task would first close the socket it sends data to
1229          * while closing the ptg file descriptors.
1230          */
1231         if (!t->src_is_sock)
1232                 close(t->src);
1233         if (t->dest_is_sock)
1234                 shutdown(t->dest, SHUT_WR);
1235         else
1236                 close(t->dest);
1237 }
1238
1239 /*
1240  * Join process, with appropriate errors on failure. Name is name for the
1241  * process (for error messages). Returns 0 on success, 1 on failure.
1242  */
1243 static int tloop_join(pid_t pid, const char *name)
1244 {
1245         int tret;
1246         if (waitpid(pid, &tret, 0) < 0) {
1247                 error("%s process failed to wait: %s", name, strerror(errno));
1248                 return 1;
1249         }
1250         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1251                 error("%s process failed", name);
1252                 return 1;
1253         }
1254         return 0;
1255 }
1256
1257 /*
1258  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1259  * -1 on failure.
1260  */
1261 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1262 {
1263         pid_t pid1, pid2;
1264         int ret = 0;
1265
1266         /* Fork thread #1: git to program. */
1267         pid1 = fork();
1268         if (pid1 < 0)
1269                 die_errno("Can't start thread for copying data");
1270         else if (pid1 == 0) {
1271                 udt_kill_transfer(&s->ptg);
1272                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1273         }
1274
1275         /* Fork thread #2: program to git. */
1276         pid2 = fork();
1277         if (pid2 < 0)
1278                 die_errno("Can't start thread for copying data");
1279         else if (pid2 == 0) {
1280                 udt_kill_transfer(&s->gtp);
1281                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1282         }
1283
1284         /*
1285          * Close both streams in parent as to not interfere with
1286          * end of file detection and wait for both tasks to finish.
1287          */
1288         udt_kill_transfer(&s->gtp);
1289         udt_kill_transfer(&s->ptg);
1290         ret |= tloop_join(pid1, "Git to program copy");
1291         ret |= tloop_join(pid2, "Program to git copy");
1292         return ret;
1293 }
1294 #endif
1295
1296 /*
1297  * Copies data from stdin to output and from input to stdout simultaneously.
1298  * Additionally filtering through given filter. If filter is NULL, uses
1299  * identity filter.
1300  */
1301 int bidirectional_transfer_loop(int input, int output)
1302 {
1303         struct bidirectional_transfer_state state;
1304
1305         /* Fill the state fields. */
1306         state.ptg.src = input;
1307         state.ptg.dest = 1;
1308         state.ptg.src_is_sock = (input == output);
1309         state.ptg.dest_is_sock = 0;
1310         state.ptg.state = SSTATE_TRANSFERING;
1311         state.ptg.bufuse = 0;
1312         state.ptg.src_name = "remote input";
1313         state.ptg.dest_name = "stdout";
1314
1315         state.gtp.src = 0;
1316         state.gtp.dest = output;
1317         state.gtp.src_is_sock = 0;
1318         state.gtp.dest_is_sock = (input == output);
1319         state.gtp.state = SSTATE_TRANSFERING;
1320         state.gtp.bufuse = 0;
1321         state.gtp.src_name = "stdin";
1322         state.gtp.dest_name = "remote output";
1323
1324         return tloop_spawnwait_tasks(&state);
1325 }