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 && starts_with(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 (starts_with(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 (starts_with(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 (starts_with(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
 273 static const char *boolean_options[] = {
 274         TRANS_OPT_THIN,
 275         TRANS_OPT_KEEP,
 276         TRANS_OPT_FOLLOWTAGS
 277         };
 278
 279 static int set_helper_option(struct transport *transport,
 280                           const char *name, const char *value)
 281 {
 282         struct helper_data *data = transport->data;
 283         struct strbuf buf = STRBUF_INIT;
 284         int i, ret, is_bool = 0;
 285
 286         get_helper(transport);
 287
 288         if (!data->option)
 289                 return 1;
 290
 291         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 292                 if (!strcmp(name, unsupported_options[i]))
 293                         return 1;
 294         }
 295
 296         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 297                 if (!strcmp(name, boolean_options[i])) {
 298                         is_bool = 1;
 299                         break;
 300                 }
 301         }
 302
 303         strbuf_addf(&buf, "option %s ", name);
 304         if (is_bool)
 305                 strbuf_addstr(&buf, value ? "true" : "false");
 306         else
 307                 quote_c_style(value, &buf, NULL, 0);
 308         strbuf_addch(&buf, '\n');
 309
 310         xchgline(data, &buf);
 311
 312         if (!strcmp(buf.buf, "ok"))
 313                 ret = 0;
 314         else if (starts_with(buf.buf, "error")) {
 315                 ret = -1;
 316         } else if (!strcmp(buf.buf, "unsupported"))
 317                 ret = 1;
 318         else {
 319                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 320                 ret = 1;
 321         }
 322         strbuf_release(&buf);
 323         return ret;
 324 }
 325
 326 static void standard_options(struct transport *t)
 327 {
 328         char buf[16];
 329         int n;
 330         int v = t->verbose;
 331
 332         set_helper_option(t, "progress", t->progress ? "true" : "false");
 333
 334         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 335         if (n >= sizeof(buf))
 336                 die("impossibly large verbosity value");
 337         set_helper_option(t, "verbosity", buf);
 338 }
 339
 340 static int release_helper(struct transport *transport)
 341 {
 342         int res = 0;
 343         struct helper_data *data = transport->data;
 344         free_refspec(data->refspec_nr, data->refspecs);
 345         data->refspecs = NULL;
 346         res = disconnect_helper(transport);
 347         free(transport->data);
 348         return res;
 349 }
 350
 351 static int fetch_with_fetch(struct transport *transport,
 352                             int nr_heads, struct ref **to_fetch)
 353 {
 354         struct helper_data *data = transport->data;
 355         int i;
 356         struct strbuf buf = STRBUF_INIT;
 357
 358         standard_options(transport);
 359         if (data->check_connectivity &&
 360             data->transport_options.check_self_contained_and_connected)
 361                 set_helper_option(transport, "check-connectivity", "true");
 362
 363         if (transport->cloning)
 364                 set_helper_option(transport, "cloning", "true");
 365
 366         if (data->transport_options.update_shallow)
 367                 set_helper_option(transport, "update-shallow", "true");
 368
 369         for (i = 0; i < nr_heads; i++) {
 370                 const struct ref *posn = to_fetch[i];
 371                 if (posn->status & REF_STATUS_UPTODATE)
 372                         continue;
 373
 374                 strbuf_addf(&buf, "fetch %s %s\n",
 375                             sha1_to_hex(posn->old_sha1), posn->name);
 376         }
 377
 378         strbuf_addch(&buf, '\n');
 379         sendline(data, &buf);
 380
 381         while (1) {
 382                 recvline(data, &buf);
 383
 384                 if (starts_with(buf.buf, "lock ")) {
 385                         const char *name = buf.buf + 5;
 386                         if (transport->pack_lockfile)
 387                                 warning("%s also locked %s", data->name, name);
 388                         else
 389                                 transport->pack_lockfile = xstrdup(name);
 390                 }
 391                 else if (data->check_connectivity &&
 392                          data->transport_options.check_self_contained_and_connected &&
 393                          !strcmp(buf.buf, "connectivity-ok"))
 394                         data->transport_options.self_contained_and_connected = 1;
 395                 else if (!buf.len)
 396                         break;
 397                 else
 398                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 399         }
 400         strbuf_release(&buf);
 401         return 0;
 402 }
 403
 404 static int get_importer(struct transport *transport, struct child_process *fastimport)
 405 {
 406         struct child_process *helper = get_helper(transport);
 407         struct helper_data *data = transport->data;
 408         struct argv_array argv = ARGV_ARRAY_INIT;
 409         int cat_blob_fd, code;
 410         memset(fastimport, 0, sizeof(*fastimport));
 411         fastimport->in = helper->out;
 412         argv_array_push(&argv, "fast-import");
 413         argv_array_push(&argv, debug ? "--stats" : "--quiet");
 414
 415         if (data->bidi_import) {
 416                 cat_blob_fd = xdup(helper->in);
 417                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 418         }
 419         fastimport->argv = argv.argv;
 420         fastimport->git_cmd = 1;
 421
 422         code = start_command(fastimport);
 423         return code;
 424 }
 425
 426 static int get_exporter(struct transport *transport,
 427                         struct child_process *fastexport,
 428                         struct string_list *revlist_args)
 429 {
 430         struct helper_data *data = transport->data;
 431         struct child_process *helper = get_helper(transport);
 432         int argc = 0, i;
 433         memset(fastexport, 0, sizeof(*fastexport));
 434
 435         /* we need to duplicate helper->in because we want to use it after
 436          * fastexport is done with it. */
 437         fastexport->out = dup(helper->in);
 438         fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
 439         fastexport->argv[argc++] = "fast-export";
 440         fastexport->argv[argc++] = "--use-done-feature";
 441         fastexport->argv[argc++] = data->signed_tags ?
 442                 "--signed-tags=verbatim" : "--signed-tags=warn-strip";
 443         if (data->export_marks)
 444                 fastexport->argv[argc++] = data->export_marks;
 445         if (data->import_marks)
 446                 fastexport->argv[argc++] = data->import_marks;
 447
 448         for (i = 0; i < revlist_args->nr; i++)
 449                 fastexport->argv[argc++] = revlist_args->items[i].string;
 450
 451         fastexport->git_cmd = 1;
 452         return start_command(fastexport);
 453 }
 454
 455 static int fetch_with_import(struct transport *transport,
 456                              int nr_heads, struct ref **to_fetch)
 457 {
 458         struct child_process fastimport;
 459         struct helper_data *data = transport->data;
 460         int i;
 461         struct ref *posn;
 462         struct strbuf buf = STRBUF_INIT;
 463
 464         get_helper(transport);
 465
 466         if (get_importer(transport, &fastimport))
 467                 die("Couldn't run fast-import");
 468
 469         for (i = 0; i < nr_heads; i++) {
 470                 posn = to_fetch[i];
 471                 if (posn->status & REF_STATUS_UPTODATE)
 472                         continue;
 473
 474                 strbuf_addf(&buf, "import %s\n", posn->name);
 475                 sendline(data, &buf);
 476                 strbuf_reset(&buf);
 477         }
 478
 479         write_constant(data->helper->in, "\n");
 480         /*
 481          * remote-helpers that advertise the bidi-import capability are required to
 482          * buffer the complete batch of import commands until this newline before
 483          * sending data to fast-import.
 484          * These helpers read back data from fast-import on their stdin, which could
 485          * be mixed with import commands, otherwise.
 486          */
 487
 488         if (finish_command(&fastimport))
 489                 die("Error while running fast-import");
 490         argv_array_free_detached(fastimport.argv);
 491
 492         /*
 493          * The fast-import stream of a remote helper that advertises
 494          * the "refspec" capability writes to the refs named after the
 495          * right hand side of the first refspec matching each ref we
 496          * were fetching.
 497          *
 498          * (If no "refspec" capability was specified, for historical
 499          * reasons we default to the equivalent of *:*.)
 500          *
 501          * Store the result in to_fetch[i].old_sha1.  Callers such
 502          * as "git fetch" can use the value to write feedback to the
 503          * terminal, populate FETCH_HEAD, and determine what new value
 504          * should be written to peer_ref if the update is a
 505          * fast-forward or this is a forced update.
 506          */
 507         for (i = 0; i < nr_heads; i++) {
 508                 char *private;
 509                 posn = to_fetch[i];
 510                 if (posn->status & REF_STATUS_UPTODATE)
 511                         continue;
 512                 if (data->refspecs)
 513                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 514                 else
 515                         private = xstrdup(posn->name);
 516                 if (private) {
 517                         read_ref(private, posn->old_sha1);
 518                         free(private);
 519                 }
 520         }
 521         strbuf_release(&buf);
 522         return 0;
 523 }
 524
 525 static int process_connect_service(struct transport *transport,
 526                                    const char *name, const char *exec)
 527 {
 528         struct helper_data *data = transport->data;
 529         struct strbuf cmdbuf = STRBUF_INIT;
 530         struct child_process *helper;
 531         int r, duped, ret = 0;
 532         FILE *input;
 533
 534         helper = get_helper(transport);
 535
 536         /*
 537          * Yes, dup the pipe another time, as we need unbuffered version
 538          * of input pipe as FILE*. fclose() closes the underlying fd and
 539          * stream buffering only can be changed before first I/O operation
 540          * on it.
 541          */
 542         duped = dup(helper->out);
 543         if (duped < 0)
 544                 die_errno("Can't dup helper output fd");
 545         input = xfdopen(duped, "r");
 546         setvbuf(input, NULL, _IONBF, 0);
 547
 548         /*
 549          * Handle --upload-pack and friends. This is fire and forget...
 550          * just warn if it fails.
 551          */
 552         if (strcmp(name, exec)) {
 553                 r = set_helper_option(transport, "servpath", exec);
 554                 if (r > 0)
 555                         warning("Setting remote service path not supported by protocol.");
 556                 else if (r < 0)
 557                         warning("Invalid remote service path.");
 558         }
 559
 560         if (data->connect)
 561                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 562         else
 563                 goto exit;
 564
 565         sendline(data, &cmdbuf);
 566         recvline_fh(input, &cmdbuf, name);
 567         if (!strcmp(cmdbuf.buf, "")) {
 568                 data->no_disconnect_req = 1;
 569                 if (debug)
 570                         fprintf(stderr, "Debug: Smart transport connection "
 571                                 "ready.\n");
 572                 ret = 1;
 573         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 574                 if (debug)
 575                         fprintf(stderr, "Debug: Falling back to dumb "
 576                                 "transport.\n");
 577         } else
 578                 die("Unknown response to connect: %s",
 579                         cmdbuf.buf);
 580
 581 exit:
 582         fclose(input);
 583         return ret;
 584 }
 585
 586 static int process_connect(struct transport *transport,
 587                                      int for_push)
 588 {
 589         struct helper_data *data = transport->data;
 590         const char *name;
 591         const char *exec;
 592
 593         name = for_push ? "git-receive-pack" : "git-upload-pack";
 594         if (for_push)
 595                 exec = data->transport_options.receivepack;
 596         else
 597                 exec = data->transport_options.uploadpack;
 598
 599         return process_connect_service(transport, name, exec);
 600 }
 601
 602 static int connect_helper(struct transport *transport, const char *name,
 603                    const char *exec, int fd[2])
 604 {
 605         struct helper_data *data = transport->data;
 606
 607         /* Get_helper so connect is inited. */
 608         get_helper(transport);
 609         if (!data->connect)
 610                 die("Operation not supported by protocol.");
 611
 612         if (!process_connect_service(transport, name, exec))
 613                 die("Can't connect to subservice %s.", name);
 614
 615         fd[0] = data->helper->out;
 616         fd[1] = data->helper->in;
 617         return 0;
 618 }
 619
 620 static int fetch(struct transport *transport,
 621                  int nr_heads, struct ref **to_fetch)
 622 {
 623         struct helper_data *data = transport->data;
 624         int i, count;
 625
 626         if (process_connect(transport, 0)) {
 627                 do_take_over(transport);
 628                 return transport->fetch(transport, nr_heads, to_fetch);
 629         }
 630
 631         count = 0;
 632         for (i = 0; i < nr_heads; i++)
 633                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 634                         count++;
 635
 636         if (!count)
 637                 return 0;
 638
 639         if (data->fetch)
 640                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 641
 642         if (data->import)
 643                 return fetch_with_import(transport, nr_heads, to_fetch);
 644
 645         return -1;
 646 }
 647
 648 static int push_update_ref_status(struct strbuf *buf,
 649                                    struct ref **ref,
 650                                    struct ref *remote_refs)
 651 {
 652         char *refname, *msg;
 653         int status, forced = 0;
 654
 655         if (starts_with(buf->buf, "ok ")) {
 656                 status = REF_STATUS_OK;
 657                 refname = buf->buf + 3;
 658         } else if (starts_with(buf->buf, "error ")) {
 659                 status = REF_STATUS_REMOTE_REJECT;
 660                 refname = buf->buf + 6;
 661         } else
 662                 die("expected ok/error, helper said '%s'", buf->buf);
 663
 664         msg = strchr(refname, ' ');
 665         if (msg) {
 666                 struct strbuf msg_buf = STRBUF_INIT;
 667                 const char *end;
 668
 669                 *msg++ = '\0';
 670                 if (!unquote_c_style(&msg_buf, msg, &end))
 671                         msg = strbuf_detach(&msg_buf, NULL);
 672                 else
 673                         msg = xstrdup(msg);
 674                 strbuf_release(&msg_buf);
 675
 676                 if (!strcmp(msg, "no match")) {
 677                         status = REF_STATUS_NONE;
 678                         free(msg);
 679                         msg = NULL;
 680                 }
 681                 else if (!strcmp(msg, "up to date")) {
 682                         status = REF_STATUS_UPTODATE;
 683                         free(msg);
 684                         msg = NULL;
 685                 }
 686                 else if (!strcmp(msg, "non-fast forward")) {
 687                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 688                         free(msg);
 689                         msg = NULL;
 690                 }
 691                 else if (!strcmp(msg, "already exists")) {
 692                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 693                         free(msg);
 694                         msg = NULL;
 695                 }
 696                 else if (!strcmp(msg, "fetch first")) {
 697                         status = REF_STATUS_REJECT_FETCH_FIRST;
 698                         free(msg);
 699                         msg = NULL;
 700                 }
 701                 else if (!strcmp(msg, "needs force")) {
 702                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 703                         free(msg);
 704                         msg = NULL;
 705                 }
 706                 else if (!strcmp(msg, "stale info")) {
 707                         status = REF_STATUS_REJECT_STALE;
 708                         free(msg);
 709                         msg = NULL;
 710                 }
 711                 else if (!strcmp(msg, "forced update")) {
 712                         forced = 1;
 713                         free(msg);
 714                         msg = NULL;
 715                 }
 716         }
 717
 718         if (*ref)
 719                 *ref = find_ref_by_name(*ref, refname);
 720         if (!*ref)
 721                 *ref = find_ref_by_name(remote_refs, refname);
 722         if (!*ref) {
 723                 warning("helper reported unexpected status of %s", refname);
 724                 return 1;
 725         }
 726
 727         if ((*ref)->status != REF_STATUS_NONE) {
 728                 /*
 729                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 730                  * status reported by the remote helper if the latter is 'no match'.
 731                  */
 732                 if (status == REF_STATUS_NONE)
 733                         return 1;
 734         }
 735
 736         (*ref)->status = status;
 737         (*ref)->forced_update |= forced;
 738         (*ref)->remote_status = msg;
 739         return !(status == REF_STATUS_OK);
 740 }
 741
 742 static void push_update_refs_status(struct helper_data *data,
 743                                     struct ref *remote_refs,
 744                                     int flags)
 745 {
 746         struct strbuf buf = STRBUF_INIT;
 747         struct ref *ref = remote_refs;
 748         for (;;) {
 749                 char *private;
 750
 751                 recvline(data, &buf);
 752                 if (!buf.len)
 753                         break;
 754
 755                 if (push_update_ref_status(&buf, &ref, remote_refs))
 756                         continue;
 757
 758                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 759                         continue;
 760
 761                 /* propagate back the update to the remote namespace */
 762                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 763                 if (!private)
 764                         continue;
 765                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 766                 free(private);
 767         }
 768         strbuf_release(&buf);
 769 }
 770
 771 static int push_refs_with_push(struct transport *transport,
 772                                struct ref *remote_refs, int flags)
 773 {
 774         int force_all = flags & TRANSPORT_PUSH_FORCE;
 775         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 776         struct helper_data *data = transport->data;
 777         struct strbuf buf = STRBUF_INIT;
 778         struct ref *ref;
 779         struct string_list cas_options = STRING_LIST_INIT_DUP;
 780         struct string_list_item *cas_option;
 781
 782         get_helper(transport);
 783         if (!data->push)
 784                 return 1;
 785
 786         for (ref = remote_refs; ref; ref = ref->next) {
 787                 if (!ref->peer_ref && !mirror)
 788                         continue;
 789
 790                 /* Check for statuses set by set_ref_status_for_push() */
 791                 switch (ref->status) {
 792                 case REF_STATUS_REJECT_NONFASTFORWARD:
 793                 case REF_STATUS_REJECT_STALE:
 794                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 795                 case REF_STATUS_UPTODATE:
 796                         continue;
 797                 default:
 798                         ; /* do nothing */
 799                 }
 800
 801                 if (force_all)
 802                         ref->force = 1;
 803
 804                 strbuf_addstr(&buf, "push ");
 805                 if (!ref->deletion) {
 806                         if (ref->force)
 807                                 strbuf_addch(&buf, '+');
 808                         if (ref->peer_ref)
 809                                 strbuf_addstr(&buf, ref->peer_ref->name);
 810                         else
 811                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 812                 }
 813                 strbuf_addch(&buf, ':');
 814                 strbuf_addstr(&buf, ref->name);
 815                 strbuf_addch(&buf, '\n');
 816
 817                 /*
 818                  * The "--force-with-lease" options without explicit
 819                  * values to expect have already been expanded into
 820                  * the ref->old_sha1_expect[] field; we can ignore
 821                  * transport->smart_options->cas altogether and instead
 822                  * can enumerate them from the refs.
 823                  */
 824                 if (ref->expect_old_sha1) {
 825                         struct strbuf cas = STRBUF_INIT;
 826                         strbuf_addf(&cas, "%s:%s",
 827                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 828                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 829                 }
 830         }
 831         if (buf.len == 0) {
 832                 string_list_clear(&cas_options, 0);
 833                 return 0;
 834         }
 835
 836         standard_options(transport);
 837         for_each_string_list_item(cas_option, &cas_options)
 838                 set_helper_option(transport, "cas", cas_option->string);
 839
 840         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 841                 if (set_helper_option(transport, "dry-run", "true") != 0)
 842                         die("helper %s does not support dry-run", data->name);
 843         }
 844
 845         strbuf_addch(&buf, '\n');
 846         sendline(data, &buf);
 847         strbuf_release(&buf);
 848
 849         push_update_refs_status(data, remote_refs, flags);
 850         return 0;
 851 }
 852
 853 static int push_refs_with_export(struct transport *transport,
 854                 struct ref *remote_refs, int flags)
 855 {
 856         struct ref *ref;
 857         struct child_process *helper, exporter;
 858         struct helper_data *data = transport->data;
 859         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 860         struct strbuf buf = STRBUF_INIT;
 861
 862         if (!data->refspecs)
 863                 die("remote-helper doesn't support push; refspec needed");
 864
 865         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 866                 if (set_helper_option(transport, "dry-run", "true") != 0)
 867                         die("helper %s does not support dry-run", data->name);
 868         }
 869
 870         if (flags & TRANSPORT_PUSH_FORCE) {
 871                 if (set_helper_option(transport, "force", "true") != 0)
 872                         warning("helper %s does not support 'force'", data->name);
 873         }
 874
 875         helper = get_helper(transport);
 876
 877         write_constant(helper->in, "export\n");
 878
 879         strbuf_reset(&buf);
 880
 881         for (ref = remote_refs; ref; ref = ref->next) {
 882                 char *private;
 883                 unsigned char sha1[20];
 884
 885                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 886                 if (private && !get_sha1(private, sha1)) {
 887                         strbuf_addf(&buf, "^%s", private);
 888                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 889                         hashcpy(ref->old_sha1, sha1);
 890                 }
 891                 free(private);
 892
 893                 if (ref->peer_ref) {
 894                         if (strcmp(ref->name, ref->peer_ref->name)) {
 895                                 struct strbuf buf = STRBUF_INIT;
 896
 897                                 if (!ref->deletion) {
 898                                         const char *name;
 899                                         int flag;
 900
 901                                         /* Follow symbolic refs (mainly for HEAD). */
 902                                         name = resolve_ref_unsafe(ref->peer_ref->name, sha1, 1, &flag);
 903                                         if (!name || !(flag & REF_ISSYMREF))
 904                                                 name = ref->peer_ref->name;
 905
 906                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 907                                 } else
 908                                         strbuf_addf(&buf, ":%s", ref->name);
 909
 910                                 string_list_append(&revlist_args, "--refspec");
 911                                 string_list_append(&revlist_args, buf.buf);
 912                                 strbuf_release(&buf);
 913                         }
 914                         if (!ref->deletion)
 915                                 string_list_append(&revlist_args, ref->peer_ref->name);
 916                 }
 917         }
 918
 919         if (get_exporter(transport, &exporter, &revlist_args))
 920                 die("Couldn't run fast-export");
 921
 922         string_list_clear(&revlist_args, 1);
 923
 924         if (finish_command(&exporter))
 925                 die("Error while running fast-export");
 926         push_update_refs_status(data, remote_refs, flags);
 927         return 0;
 928 }
 929
 930 static int push_refs(struct transport *transport,
 931                 struct ref *remote_refs, int flags)
 932 {
 933         struct helper_data *data = transport->data;
 934
 935         if (process_connect(transport, 1)) {
 936                 do_take_over(transport);
 937                 return transport->push_refs(transport, remote_refs, flags);
 938         }
 939
 940         if (!remote_refs) {
 941                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 942                         "Perhaps you should specify a branch such as 'master'.\n");
 943                 return 0;
 944         }
 945
 946         if (data->push)
 947                 return push_refs_with_push(transport, remote_refs, flags);
 948
 949         if (data->export)
 950                 return push_refs_with_export(transport, remote_refs, flags);
 951
 952         return -1;
 953 }
 954
 955
 956 static int has_attribute(const char *attrs, const char *attr) {
 957         int len;
 958         if (!attrs)
 959                 return 0;
 960
 961         len = strlen(attr);
 962         for (;;) {
 963                 const char *space = strchrnul(attrs, ' ');
 964                 if (len == space - attrs && !strncmp(attrs, attr, len))
 965                         return 1;
 966                 if (!*space)
 967                         return 0;
 968                 attrs = space + 1;
 969         }
 970 }
 971
 972 static struct ref *get_refs_list(struct transport *transport, int for_push)
 973 {
 974         struct helper_data *data = transport->data;
 975         struct child_process *helper;
 976         struct ref *ret = NULL;
 977         struct ref **tail = &ret;
 978         struct ref *posn;
 979         struct strbuf buf = STRBUF_INIT;
 980
 981         helper = get_helper(transport);
 982
 983         if (process_connect(transport, for_push)) {
 984                 do_take_over(transport);
 985                 return transport->get_refs_list(transport, for_push);
 986         }
 987
 988         if (data->push && for_push)
 989                 write_str_in_full(helper->in, "list for-push\n");
 990         else
 991                 write_str_in_full(helper->in, "list\n");
 992
 993         while (1) {
 994                 char *eov, *eon;
 995                 recvline(data, &buf);
 996
 997                 if (!*buf.buf)
 998                         break;
 999
1000                 eov = strchr(buf.buf, ' ');
1001                 if (!eov)
1002                         die("Malformed response in ref list: %s", buf.buf);
1003                 eon = strchr(eov + 1, ' ');
1004                 *eov = '\0';
1005                 if (eon)
1006                         *eon = '\0';
1007                 *tail = alloc_ref(eov + 1);
1008                 if (buf.buf[0] == '@')
1009                         (*tail)->symref = xstrdup(buf.buf + 1);
1010                 else if (buf.buf[0] != '?')
1011                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1012                 if (eon) {
1013                         if (has_attribute(eon + 1, "unchanged")) {
1014                                 (*tail)->status |= REF_STATUS_UPTODATE;
1015                                 read_ref((*tail)->name, (*tail)->old_sha1);
1016                         }
1017                 }
1018                 tail = &((*tail)->next);
1019         }
1020         if (debug)
1021                 fprintf(stderr, "Debug: Read ref listing.\n");
1022         strbuf_release(&buf);
1023
1024         for (posn = ret; posn; posn = posn->next)
1025                 resolve_remote_symref(posn, ret);
1026
1027         return ret;
1028 }
1029
1030 int transport_helper_init(struct transport *transport, const char *name)
1031 {
1032         struct helper_data *data = xcalloc(sizeof(*data), 1);
1033         data->name = name;
1034
1035         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1036                 debug = 1;
1037
1038         transport->data = data;
1039         transport->set_option = set_helper_option;
1040         transport->get_refs_list = get_refs_list;
1041         transport->fetch = fetch;
1042         transport->push_refs = push_refs;
1043         transport->disconnect = release_helper;
1044         transport->connect = connect_helper;
1045         transport->smart_options = &(data->transport_options);
1046         return 0;
1047 }
1048
1049 /*
1050  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1051  * buffer less), so attempt reads and writes with up to that size.
1052  */
1053 #define BUFFERSIZE 65536
1054 /* This should be enough to hold debugging message. */
1055 #define PBUFFERSIZE 8192
1056
1057 /* Print bidirectional transfer loop debug message. */
1058 __attribute__((format (printf, 1, 2)))
1059 static void transfer_debug(const char *fmt, ...)
1060 {
1061         va_list args;
1062         char msgbuf[PBUFFERSIZE];
1063         static int debug_enabled = -1;
1064
1065         if (debug_enabled < 0)
1066                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1067         if (!debug_enabled)
1068                 return;
1069
1070         va_start(args, fmt);
1071         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1072         va_end(args);
1073         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1074 }
1075
1076 /* Stream state: More data may be coming in this direction. */
1077 #define SSTATE_TRANSFERING 0
1078 /*
1079  * Stream state: No more data coming in this direction, flushing rest of
1080  * data.
1081  */
1082 #define SSTATE_FLUSHING 1
1083 /* Stream state: Transfer in this direction finished. */
1084 #define SSTATE_FINISHED 2
1085
1086 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1087 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1088 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1089
1090 /* Unidirectional transfer. */
1091 struct unidirectional_transfer {
1092         /* Source */
1093         int src;
1094         /* Destination */
1095         int dest;
1096         /* Is source socket? */
1097         int src_is_sock;
1098         /* Is destination socket? */
1099         int dest_is_sock;
1100         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1101         int state;
1102         /* Buffer. */
1103         char buf[BUFFERSIZE];
1104         /* Buffer used. */
1105         size_t bufuse;
1106         /* Name of source. */
1107         const char *src_name;
1108         /* Name of destination. */
1109         const char *dest_name;
1110 };
1111
1112 /* Closes the target (for writing) if transfer has finished. */
1113 static void udt_close_if_finished(struct unidirectional_transfer *t)
1114 {
1115         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1116                 t->state = SSTATE_FINISHED;
1117                 if (t->dest_is_sock)
1118                         shutdown(t->dest, SHUT_WR);
1119                 else
1120                         close(t->dest);
1121                 transfer_debug("Closed %s.", t->dest_name);
1122         }
1123 }
1124
1125 /*
1126  * Tries to read read data from source into buffer. If buffer is full,
1127  * no data is read. Returns 0 on success, -1 on error.
1128  */
1129 static int udt_do_read(struct unidirectional_transfer *t)
1130 {
1131         ssize_t bytes;
1132
1133         if (t->bufuse == BUFFERSIZE)
1134                 return 0;       /* No space for more. */
1135
1136         transfer_debug("%s is readable", t->src_name);
1137         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1138         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1139                 errno != EINTR) {
1140                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1141                 return -1;
1142         } else if (bytes == 0) {
1143                 transfer_debug("%s EOF (with %i bytes in buffer)",
1144                         t->src_name, (int)t->bufuse);
1145                 t->state = SSTATE_FLUSHING;
1146         } else if (bytes > 0) {
1147                 t->bufuse += bytes;
1148                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1149                         (int)bytes, t->src_name, (int)t->bufuse);
1150         }
1151         return 0;
1152 }
1153
1154 /* Tries to write data from buffer into destination. If buffer is empty,
1155  * no data is written. Returns 0 on success, -1 on error.
1156  */
1157 static int udt_do_write(struct unidirectional_transfer *t)
1158 {
1159         ssize_t bytes;
1160
1161         if (t->bufuse == 0)
1162                 return 0;       /* Nothing to write. */
1163
1164         transfer_debug("%s is writable", t->dest_name);
1165         bytes = xwrite(t->dest, t->buf, t->bufuse);
1166         if (bytes < 0 && errno != EWOULDBLOCK) {
1167                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1168                 return -1;
1169         } else if (bytes > 0) {
1170                 t->bufuse -= bytes;
1171                 if (t->bufuse)
1172                         memmove(t->buf, t->buf + bytes, t->bufuse);
1173                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1174                         (int)bytes, t->dest_name, (int)t->bufuse);
1175         }
1176         return 0;
1177 }
1178
1179
1180 /* State of bidirectional transfer loop. */
1181 struct bidirectional_transfer_state {
1182         /* Direction from program to git. */
1183         struct unidirectional_transfer ptg;
1184         /* Direction from git to program. */
1185         struct unidirectional_transfer gtp;
1186 };
1187
1188 static void *udt_copy_task_routine(void *udt)
1189 {
1190         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1191         while (t->state != SSTATE_FINISHED) {
1192                 if (STATE_NEEDS_READING(t->state))
1193                         if (udt_do_read(t))
1194                                 return NULL;
1195                 if (STATE_NEEDS_WRITING(t->state))
1196                         if (udt_do_write(t))
1197                                 return NULL;
1198                 if (STATE_NEEDS_CLOSING(t->state))
1199                         udt_close_if_finished(t);
1200         }
1201         return udt;     /* Just some non-NULL value. */
1202 }
1203
1204 #ifndef NO_PTHREADS
1205
1206 /*
1207  * Join thread, with appropriate errors on failure. Name is name for the
1208  * thread (for error messages). Returns 0 on success, 1 on failure.
1209  */
1210 static int tloop_join(pthread_t thread, const char *name)
1211 {
1212         int err;
1213         void *tret;
1214         err = pthread_join(thread, &tret);
1215         if (!tret) {
1216                 error("%s thread failed", name);
1217                 return 1;
1218         }
1219         if (err) {
1220                 error("%s thread failed to join: %s", name, strerror(err));
1221                 return 1;
1222         }
1223         return 0;
1224 }
1225
1226 /*
1227  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1228  * -1 on failure.
1229  */
1230 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1231 {
1232         pthread_t gtp_thread;
1233         pthread_t ptg_thread;
1234         int err;
1235         int ret = 0;
1236         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1237                 &s->gtp);
1238         if (err)
1239                 die("Can't start thread for copying data: %s", strerror(err));
1240         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1241                 &s->ptg);
1242         if (err)
1243                 die("Can't start thread for copying data: %s", strerror(err));
1244
1245         ret |= tloop_join(gtp_thread, "Git to program copy");
1246         ret |= tloop_join(ptg_thread, "Program to git copy");
1247         return ret;
1248 }
1249 #else
1250
1251 /* Close the source and target (for writing) for transfer. */
1252 static void udt_kill_transfer(struct unidirectional_transfer *t)
1253 {
1254         t->state = SSTATE_FINISHED;
1255         /*
1256          * Socket read end left open isn't a disaster if nobody
1257          * attempts to read from it (mingw compat headers do not
1258          * have SHUT_RD)...
1259          *
1260          * We can't fully close the socket since otherwise gtp
1261          * task would first close the socket it sends data to
1262          * while closing the ptg file descriptors.
1263          */
1264         if (!t->src_is_sock)
1265                 close(t->src);
1266         if (t->dest_is_sock)
1267                 shutdown(t->dest, SHUT_WR);
1268         else
1269                 close(t->dest);
1270 }
1271
1272 /*
1273  * Join process, with appropriate errors on failure. Name is name for the
1274  * process (for error messages). Returns 0 on success, 1 on failure.
1275  */
1276 static int tloop_join(pid_t pid, const char *name)
1277 {
1278         int tret;
1279         if (waitpid(pid, &tret, 0) < 0) {
1280                 error("%s process failed to wait: %s", name, strerror(errno));
1281                 return 1;
1282         }
1283         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1284                 error("%s process failed", name);
1285                 return 1;
1286         }
1287         return 0;
1288 }
1289
1290 /*
1291  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1292  * -1 on failure.
1293  */
1294 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1295 {
1296         pid_t pid1, pid2;
1297         int ret = 0;
1298
1299         /* Fork thread #1: git to program. */
1300         pid1 = fork();
1301         if (pid1 < 0)
1302                 die_errno("Can't start thread for copying data");
1303         else if (pid1 == 0) {
1304                 udt_kill_transfer(&s->ptg);
1305                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1306         }
1307
1308         /* Fork thread #2: program to git. */
1309         pid2 = fork();
1310         if (pid2 < 0)
1311                 die_errno("Can't start thread for copying data");
1312         else if (pid2 == 0) {
1313                 udt_kill_transfer(&s->gtp);
1314                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1315         }
1316
1317         /*
1318          * Close both streams in parent as to not interfere with
1319          * end of file detection and wait for both tasks to finish.
1320          */
1321         udt_kill_transfer(&s->gtp);
1322         udt_kill_transfer(&s->ptg);
1323         ret |= tloop_join(pid1, "Git to program copy");
1324         ret |= tloop_join(pid2, "Program to git copy");
1325         return ret;
1326 }
1327 #endif
1328
1329 /*
1330  * Copies data from stdin to output and from input to stdout simultaneously.
1331  * Additionally filtering through given filter. If filter is NULL, uses
1332  * identity filter.
1333  */
1334 int bidirectional_transfer_loop(int input, int output)
1335 {
1336         struct bidirectional_transfer_state state;
1337
1338         /* Fill the state fields. */
1339         state.ptg.src = input;
1340         state.ptg.dest = 1;
1341         state.ptg.src_is_sock = (input == output);
1342         state.ptg.dest_is_sock = 0;
1343         state.ptg.state = SSTATE_TRANSFERING;
1344         state.ptg.bufuse = 0;
1345         state.ptg.src_name = "remote input";
1346         state.ptg.dest_name = "stdout";
1347
1348         state.gtp.src = 0;
1349         state.gtp.dest = output;
1350         state.gtp.src_is_sock = 0;
1351         state.gtp.dest_is_sock = (input == output);
1352         state.gtp.state = SSTATE_TRANSFERING;
1353         state.gtp.bufuse = 0;
1354         state.gtp.src_name = "stdin";
1355         state.gtp.dest_name = "remote output";
1356
1357         return tloop_spawnwait_tasks(&state);
1358 }