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                 no_disconnect_req : 1;
  31         char *export_marks;
  32         char *import_marks;
  33         /* These go from remote name (as in "list") to private name */
  34         struct refspec *refspecs;
  35         int refspec_nr;
  36         /* Transport options for fetch-pack/send-pack (should one of
  37          * those be invoked).
  38          */
  39         struct git_transport_options transport_options;
  40 };
  41
  42 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  43 {
  44         if (debug)
  45                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  46         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  47                 != buffer->len)
  48                 die_errno("Full write to remote helper failed");
  49 }
  50
  51 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  52 {
  53         strbuf_reset(buffer);
  54         if (debug)
  55                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  56         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  57                 if (debug)
  58                         fprintf(stderr, "Debug: Remote helper quit.\n");
  59                 die("Reading from helper 'git-remote-%s' failed", name);
  60         }
  61
  62         if (debug)
  63                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  64         return 0;
  65 }
  66
  67 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  68 {
  69         return recvline_fh(helper->out, buffer, helper->name);
  70 }
  71
  72 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  73 {
  74         sendline(helper, buffer);
  75         recvline(helper, buffer);
  76 }
  77
  78 static void write_constant(int fd, const char *str)
  79 {
  80         if (debug)
  81                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  82         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  83                 die_errno("Full write to remote helper failed");
  84 }
  85
  86 static const char *remove_ext_force(const char *url)
  87 {
  88         if (url) {
  89                 const char *colon = strchr(url, ':');
  90                 if (colon && colon[1] == ':')
  91                         return colon + 2;
  92         }
  93         return url;
  94 }
  95
  96 static void do_take_over(struct transport *transport)
  97 {
  98         struct helper_data *data;
  99         data = (struct helper_data *)transport->data;
 100         transport_take_over(transport, data->helper);
 101         fclose(data->out);
 102         free(data);
 103 }
 104
 105 static struct child_process *get_helper(struct transport *transport)
 106 {
 107         struct helper_data *data = transport->data;
 108         struct argv_array argv = ARGV_ARRAY_INIT;
 109         struct strbuf buf = STRBUF_INIT;
 110         struct child_process *helper;
 111         const char **refspecs = NULL;
 112         int refspec_nr = 0;
 113         int refspec_alloc = 0;
 114         int duped;
 115         int code;
 116         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 117         const char *helper_env[] = {
 118                 git_dir_buf,
 119                 NULL
 120         };
 121
 122
 123         if (data->helper)
 124                 return data->helper;
 125
 126         helper = xcalloc(1, sizeof(*helper));
 127         helper->in = -1;
 128         helper->out = -1;
 129         helper->err = 0;
 130         argv_array_pushf(&argv, "git-remote-%s", data->name);
 131         argv_array_push(&argv, transport->remote->name);
 132         argv_array_push(&argv, remove_ext_force(transport->url));
 133         helper->argv = argv_array_detach(&argv, NULL);
 134         helper->git_cmd = 0;
 135         helper->silent_exec_failure = 1;
 136
 137         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 138         helper->env = helper_env;
 139
 140         code = start_command(helper);
 141         if (code < 0 && errno == ENOENT)
 142                 die("Unable to find remote helper for '%s'", data->name);
 143         else if (code != 0)
 144                 exit(code);
 145
 146         data->helper = helper;
 147         data->no_disconnect_req = 0;
 148
 149         /*
 150          * Open the output as FILE* so strbuf_getline() can be used.
 151          * Do this with duped fd because fclose() will close the fd,
 152          * and stuff like taking over will require the fd to remain.
 153          */
 154         duped = dup(helper->out);
 155         if (duped < 0)
 156                 die_errno("Can't dup helper output fd");
 157         data->out = xfdopen(duped, "r");
 158
 159         write_constant(helper->in, "capabilities\n");
 160
 161         while (1) {
 162                 const char *capname;
 163                 int mandatory = 0;
 164                 recvline(data, &buf);
 165
 166                 if (!*buf.buf)
 167                         break;
 168
 169                 if (*buf.buf == '*') {
 170                         capname = buf.buf + 1;
 171                         mandatory = 1;
 172                 } else
 173                         capname = buf.buf;
 174
 175                 if (debug)
 176                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 177                 if (!strcmp(capname, "fetch"))
 178                         data->fetch = 1;
 179                 else if (!strcmp(capname, "option"))
 180                         data->option = 1;
 181                 else if (!strcmp(capname, "push"))
 182                         data->push = 1;
 183                 else if (!strcmp(capname, "import"))
 184                         data->import = 1;
 185                 else if (!strcmp(capname, "bidi-import"))
 186                         data->bidi_import = 1;
 187                 else if (!strcmp(capname, "export"))
 188                         data->export = 1;
 189                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 190                         ALLOC_GROW(refspecs,
 191                                    refspec_nr + 1,
 192                                    refspec_alloc);
 193                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 194                 } else if (!strcmp(capname, "connect")) {
 195                         data->connect = 1;
 196                 } else if (!strcmp(capname, "signed-tags")) {
 197                         data->signed_tags = 1;
 198                 } else if (!prefixcmp(capname, "export-marks ")) {
 199                         struct strbuf arg = STRBUF_INIT;
 200                         strbuf_addstr(&arg, "--export-marks=");
 201                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 202                         data->export_marks = strbuf_detach(&arg, NULL);
 203                 } else if (!prefixcmp(capname, "import-marks")) {
 204                         struct strbuf arg = STRBUF_INIT;
 205                         strbuf_addstr(&arg, "--import-marks=");
 206                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 207                         data->import_marks = strbuf_detach(&arg, NULL);
 208                 } else if (mandatory) {
 209                         die("Unknown mandatory capability %s. This remote "
 210                             "helper probably needs newer version of Git.",
 211                             capname);
 212                 }
 213         }
 214         if (refspecs) {
 215                 int i;
 216                 data->refspec_nr = refspec_nr;
 217                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 218                 for (i = 0; i < refspec_nr; i++)
 219                         free((char *)refspecs[i]);
 220                 free(refspecs);
 221         } else if (data->import || data->bidi_import || data->export) {
 222                 warning("This remote helper should implement refspec capability.");
 223         }
 224         strbuf_release(&buf);
 225         if (debug)
 226                 fprintf(stderr, "Debug: Capabilities complete.\n");
 227         return data->helper;
 228 }
 229
 230 static int disconnect_helper(struct transport *transport)
 231 {
 232         struct helper_data *data = transport->data;
 233         int res = 0;
 234
 235         if (data->helper) {
 236                 if (debug)
 237                         fprintf(stderr, "Debug: Disconnecting.\n");
 238                 if (!data->no_disconnect_req) {
 239                         /*
 240                          * Ignore write errors; there's nothing we can do,
 241                          * since we're about to close the pipe anyway. And the
 242                          * most likely error is EPIPE due to the helper dying
 243                          * to report an error itself.
 244                          */
 245                         sigchain_push(SIGPIPE, SIG_IGN);
 246                         xwrite(data->helper->in, "\n", 1);
 247                         sigchain_pop(SIGPIPE);
 248                 }
 249                 close(data->helper->in);
 250                 close(data->helper->out);
 251                 fclose(data->out);
 252                 res = finish_command(data->helper);
 253                 argv_array_free_detached(data->helper->argv);
 254                 free(data->helper);
 255                 data->helper = NULL;
 256         }
 257         return res;
 258 }
 259
 260 static const char *unsupported_options[] = {
 261         TRANS_OPT_UPLOADPACK,
 262         TRANS_OPT_RECEIVEPACK,
 263         TRANS_OPT_THIN,
 264         TRANS_OPT_KEEP
 265         };
 266 static const char *boolean_options[] = {
 267         TRANS_OPT_THIN,
 268         TRANS_OPT_KEEP,
 269         TRANS_OPT_FOLLOWTAGS
 270         };
 271
 272 static int set_helper_option(struct transport *transport,
 273                           const char *name, const char *value)
 274 {
 275         struct helper_data *data = transport->data;
 276         struct strbuf buf = STRBUF_INIT;
 277         int i, ret, is_bool = 0;
 278
 279         get_helper(transport);
 280
 281         if (!data->option)
 282                 return 1;
 283
 284         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 285                 if (!strcmp(name, unsupported_options[i]))
 286                         return 1;
 287         }
 288
 289         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 290                 if (!strcmp(name, boolean_options[i])) {
 291                         is_bool = 1;
 292                         break;
 293                 }
 294         }
 295
 296         strbuf_addf(&buf, "option %s ", name);
 297         if (is_bool)
 298                 strbuf_addstr(&buf, value ? "true" : "false");
 299         else
 300                 quote_c_style(value, &buf, NULL, 0);
 301         strbuf_addch(&buf, '\n');
 302
 303         xchgline(data, &buf);
 304
 305         if (!strcmp(buf.buf, "ok"))
 306                 ret = 0;
 307         else if (!prefixcmp(buf.buf, "error")) {
 308                 ret = -1;
 309         } else if (!strcmp(buf.buf, "unsupported"))
 310                 ret = 1;
 311         else {
 312                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 313                 ret = 1;
 314         }
 315         strbuf_release(&buf);
 316         return ret;
 317 }
 318
 319 static void standard_options(struct transport *t)
 320 {
 321         char buf[16];
 322         int n;
 323         int v = t->verbose;
 324
 325         set_helper_option(t, "progress", t->progress ? "true" : "false");
 326
 327         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 328         if (n >= sizeof(buf))
 329                 die("impossibly large verbosity value");
 330         set_helper_option(t, "verbosity", buf);
 331 }
 332
 333 static int release_helper(struct transport *transport)
 334 {
 335         int res = 0;
 336         struct helper_data *data = transport->data;
 337         free_refspec(data->refspec_nr, data->refspecs);
 338         data->refspecs = NULL;
 339         res = disconnect_helper(transport);
 340         free(transport->data);
 341         return res;
 342 }
 343
 344 static int fetch_with_fetch(struct transport *transport,
 345                             int nr_heads, struct ref **to_fetch)
 346 {
 347         struct helper_data *data = transport->data;
 348         int i;
 349         struct strbuf buf = STRBUF_INIT;
 350
 351         standard_options(transport);
 352
 353         for (i = 0; i < nr_heads; i++) {
 354                 const struct ref *posn = to_fetch[i];
 355                 if (posn->status & REF_STATUS_UPTODATE)
 356                         continue;
 357
 358                 strbuf_addf(&buf, "fetch %s %s\n",
 359                             sha1_to_hex(posn->old_sha1), posn->name);
 360         }
 361
 362         strbuf_addch(&buf, '\n');
 363         sendline(data, &buf);
 364
 365         while (1) {
 366                 recvline(data, &buf);
 367
 368                 if (!prefixcmp(buf.buf, "lock ")) {
 369                         const char *name = buf.buf + 5;
 370                         if (transport->pack_lockfile)
 371                                 warning("%s also locked %s", data->name, name);
 372                         else
 373                                 transport->pack_lockfile = xstrdup(name);
 374                 }
 375                 else if (!buf.len)
 376                         break;
 377                 else
 378                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 379         }
 380         strbuf_release(&buf);
 381         return 0;
 382 }
 383
 384 static int get_importer(struct transport *transport, struct child_process *fastimport)
 385 {
 386         struct child_process *helper = get_helper(transport);
 387         struct helper_data *data = transport->data;
 388         struct argv_array argv = ARGV_ARRAY_INIT;
 389         int cat_blob_fd, code;
 390         memset(fastimport, 0, sizeof(*fastimport));
 391         fastimport->in = helper->out;
 392         argv_array_push(&argv, "fast-import");
 393         argv_array_push(&argv, debug ? "--stats" : "--quiet");
 394
 395         if (data->bidi_import) {
 396                 cat_blob_fd = xdup(helper->in);
 397                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 398         }
 399         fastimport->argv = argv.argv;
 400         fastimport->git_cmd = 1;
 401
 402         code = start_command(fastimport);
 403         return code;
 404 }
 405
 406 static int get_exporter(struct transport *transport,
 407                         struct child_process *fastexport,
 408                         struct string_list *revlist_args)
 409 {
 410         struct helper_data *data = transport->data;
 411         struct child_process *helper = get_helper(transport);
 412         int argc = 0, i;
 413         memset(fastexport, 0, sizeof(*fastexport));
 414
 415         /* we need to duplicate helper->in because we want to use it after
 416          * fastexport is done with it. */
 417         fastexport->out = dup(helper->in);
 418         fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
 419         fastexport->argv[argc++] = "fast-export";
 420         fastexport->argv[argc++] = "--use-done-feature";
 421         fastexport->argv[argc++] = data->signed_tags ?
 422                 "--signed-tags=verbatim" : "--signed-tags=warn-strip";
 423         if (data->export_marks)
 424                 fastexport->argv[argc++] = data->export_marks;
 425         if (data->import_marks)
 426                 fastexport->argv[argc++] = data->import_marks;
 427
 428         for (i = 0; i < revlist_args->nr; i++)
 429                 fastexport->argv[argc++] = revlist_args->items[i].string;
 430
 431         fastexport->git_cmd = 1;
 432         return start_command(fastexport);
 433 }
 434
 435 static int fetch_with_import(struct transport *transport,
 436                              int nr_heads, struct ref **to_fetch)
 437 {
 438         struct child_process fastimport;
 439         struct helper_data *data = transport->data;
 440         int i;
 441         struct ref *posn;
 442         struct strbuf buf = STRBUF_INIT;
 443
 444         get_helper(transport);
 445
 446         if (get_importer(transport, &fastimport))
 447                 die("Couldn't run fast-import");
 448
 449         for (i = 0; i < nr_heads; i++) {
 450                 posn = to_fetch[i];
 451                 if (posn->status & REF_STATUS_UPTODATE)
 452                         continue;
 453
 454                 strbuf_addf(&buf, "import %s\n", posn->name);
 455                 sendline(data, &buf);
 456                 strbuf_reset(&buf);
 457         }
 458
 459         write_constant(data->helper->in, "\n");
 460         /*
 461          * remote-helpers that advertise the bidi-import capability are required to
 462          * buffer the complete batch of import commands until this newline before
 463          * sending data to fast-import.
 464          * These helpers read back data from fast-import on their stdin, which could
 465          * be mixed with import commands, otherwise.
 466          */
 467
 468         if (finish_command(&fastimport))
 469                 die("Error while running fast-import");
 470         argv_array_free_detached(fastimport.argv);
 471
 472         /*
 473          * The fast-import stream of a remote helper that advertises
 474          * the "refspec" capability writes to the refs named after the
 475          * right hand side of the first refspec matching each ref we
 476          * were fetching.
 477          *
 478          * (If no "refspec" capability was specified, for historical
 479          * reasons we default to the equivalent of *:*.)
 480          *
 481          * Store the result in to_fetch[i].old_sha1.  Callers such
 482          * as "git fetch" can use the value to write feedback to the
 483          * terminal, populate FETCH_HEAD, and determine what new value
 484          * should be written to peer_ref if the update is a
 485          * fast-forward or this is a forced update.
 486          */
 487         for (i = 0; i < nr_heads; i++) {
 488                 char *private;
 489                 posn = to_fetch[i];
 490                 if (posn->status & REF_STATUS_UPTODATE)
 491                         continue;
 492                 if (data->refspecs)
 493                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 494                 else
 495                         private = xstrdup(posn->name);
 496                 if (private) {
 497                         read_ref(private, posn->old_sha1);
 498                         free(private);
 499                 }
 500         }
 501         strbuf_release(&buf);
 502         return 0;
 503 }
 504
 505 static int process_connect_service(struct transport *transport,
 506                                    const char *name, const char *exec)
 507 {
 508         struct helper_data *data = transport->data;
 509         struct strbuf cmdbuf = STRBUF_INIT;
 510         struct child_process *helper;
 511         int r, duped, ret = 0;
 512         FILE *input;
 513
 514         helper = get_helper(transport);
 515
 516         /*
 517          * Yes, dup the pipe another time, as we need unbuffered version
 518          * of input pipe as FILE*. fclose() closes the underlying fd and
 519          * stream buffering only can be changed before first I/O operation
 520          * on it.
 521          */
 522         duped = dup(helper->out);
 523         if (duped < 0)
 524                 die_errno("Can't dup helper output fd");
 525         input = xfdopen(duped, "r");
 526         setvbuf(input, NULL, _IONBF, 0);
 527
 528         /*
 529          * Handle --upload-pack and friends. This is fire and forget...
 530          * just warn if it fails.
 531          */
 532         if (strcmp(name, exec)) {
 533                 r = set_helper_option(transport, "servpath", exec);
 534                 if (r > 0)
 535                         warning("Setting remote service path not supported by protocol.");
 536                 else if (r < 0)
 537                         warning("Invalid remote service path.");
 538         }
 539
 540         if (data->connect)
 541                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 542         else
 543                 goto exit;
 544
 545         sendline(data, &cmdbuf);
 546         recvline_fh(input, &cmdbuf, name);
 547         if (!strcmp(cmdbuf.buf, "")) {
 548                 data->no_disconnect_req = 1;
 549                 if (debug)
 550                         fprintf(stderr, "Debug: Smart transport connection "
 551                                 "ready.\n");
 552                 ret = 1;
 553         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 554                 if (debug)
 555                         fprintf(stderr, "Debug: Falling back to dumb "
 556                                 "transport.\n");
 557         } else
 558                 die("Unknown response to connect: %s",
 559                         cmdbuf.buf);
 560
 561 exit:
 562         fclose(input);
 563         return ret;
 564 }
 565
 566 static int process_connect(struct transport *transport,
 567                                      int for_push)
 568 {
 569         struct helper_data *data = transport->data;
 570         const char *name;
 571         const char *exec;
 572
 573         name = for_push ? "git-receive-pack" : "git-upload-pack";
 574         if (for_push)
 575                 exec = data->transport_options.receivepack;
 576         else
 577                 exec = data->transport_options.uploadpack;
 578
 579         return process_connect_service(transport, name, exec);
 580 }
 581
 582 static int connect_helper(struct transport *transport, const char *name,
 583                    const char *exec, int fd[2])
 584 {
 585         struct helper_data *data = transport->data;
 586
 587         /* Get_helper so connect is inited. */
 588         get_helper(transport);
 589         if (!data->connect)
 590                 die("Operation not supported by protocol.");
 591
 592         if (!process_connect_service(transport, name, exec))
 593                 die("Can't connect to subservice %s.", name);
 594
 595         fd[0] = data->helper->out;
 596         fd[1] = data->helper->in;
 597         return 0;
 598 }
 599
 600 static int fetch(struct transport *transport,
 601                  int nr_heads, struct ref **to_fetch)
 602 {
 603         struct helper_data *data = transport->data;
 604         int i, count;
 605
 606         if (process_connect(transport, 0)) {
 607                 do_take_over(transport);
 608                 return transport->fetch(transport, nr_heads, to_fetch);
 609         }
 610
 611         count = 0;
 612         for (i = 0; i < nr_heads; i++)
 613                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 614                         count++;
 615
 616         if (!count)
 617                 return 0;
 618
 619         if (data->fetch)
 620                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 621
 622         if (data->import)
 623                 return fetch_with_import(transport, nr_heads, to_fetch);
 624
 625         return -1;
 626 }
 627
 628 static int push_update_ref_status(struct strbuf *buf,
 629                                    struct ref **ref,
 630                                    struct ref *remote_refs)
 631 {
 632         char *refname, *msg;
 633         int status;
 634
 635         if (!prefixcmp(buf->buf, "ok ")) {
 636                 status = REF_STATUS_OK;
 637                 refname = buf->buf + 3;
 638         } else if (!prefixcmp(buf->buf, "error ")) {
 639                 status = REF_STATUS_REMOTE_REJECT;
 640                 refname = buf->buf + 6;
 641         } else
 642                 die("expected ok/error, helper said '%s'", buf->buf);
 643
 644         msg = strchr(refname, ' ');
 645         if (msg) {
 646                 struct strbuf msg_buf = STRBUF_INIT;
 647                 const char *end;
 648
 649                 *msg++ = '\0';
 650                 if (!unquote_c_style(&msg_buf, msg, &end))
 651                         msg = strbuf_detach(&msg_buf, NULL);
 652                 else
 653                         msg = xstrdup(msg);
 654                 strbuf_release(&msg_buf);
 655
 656                 if (!strcmp(msg, "no match")) {
 657                         status = REF_STATUS_NONE;
 658                         free(msg);
 659                         msg = NULL;
 660                 }
 661                 else if (!strcmp(msg, "up to date")) {
 662                         status = REF_STATUS_UPTODATE;
 663                         free(msg);
 664                         msg = NULL;
 665                 }
 666                 else if (!strcmp(msg, "non-fast forward")) {
 667                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 668                         free(msg);
 669                         msg = NULL;
 670                 }
 671                 else if (!strcmp(msg, "already exists")) {
 672                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 673                         free(msg);
 674                         msg = NULL;
 675                 }
 676                 else if (!strcmp(msg, "fetch first")) {
 677                         status = REF_STATUS_REJECT_FETCH_FIRST;
 678                         free(msg);
 679                         msg = NULL;
 680                 }
 681                 else if (!strcmp(msg, "needs force")) {
 682                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 683                         free(msg);
 684                         msg = NULL;
 685                 }
 686         }
 687
 688         if (*ref)
 689                 *ref = find_ref_by_name(*ref, refname);
 690         if (!*ref)
 691                 *ref = find_ref_by_name(remote_refs, refname);
 692         if (!*ref) {
 693                 warning("helper reported unexpected status of %s", refname);
 694                 return 1;
 695         }
 696
 697         if ((*ref)->status != REF_STATUS_NONE) {
 698                 /*
 699                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 700                  * status reported by the remote helper if the latter is 'no match'.
 701                  */
 702                 if (status == REF_STATUS_NONE)
 703                         return 1;
 704         }
 705
 706         (*ref)->status = status;
 707         (*ref)->remote_status = msg;
 708         return !(status == REF_STATUS_OK);
 709 }
 710
 711 static void push_update_refs_status(struct helper_data *data,
 712                                     struct ref *remote_refs)
 713 {
 714         struct strbuf buf = STRBUF_INIT;
 715         struct ref *ref = remote_refs;
 716         for (;;) {
 717                 char *private;
 718
 719                 recvline(data, &buf);
 720                 if (!buf.len)
 721                         break;
 722
 723                 if (push_update_ref_status(&buf, &ref, remote_refs))
 724                         continue;
 725
 726                 if (!data->refspecs)
 727                         continue;
 728
 729                 /* propagate back the update to the remote namespace */
 730                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 731                 if (!private)
 732                         continue;
 733                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 734                 free(private);
 735         }
 736         strbuf_release(&buf);
 737 }
 738
 739 static int push_refs_with_push(struct transport *transport,
 740                 struct ref *remote_refs, int flags)
 741 {
 742         int force_all = flags & TRANSPORT_PUSH_FORCE;
 743         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 744         struct helper_data *data = transport->data;
 745         struct strbuf buf = STRBUF_INIT;
 746         struct ref *ref;
 747
 748         get_helper(transport);
 749         if (!data->push)
 750                 return 1;
 751
 752         for (ref = remote_refs; ref; ref = ref->next) {
 753                 if (!ref->peer_ref && !mirror)
 754                         continue;
 755
 756                 /* Check for statuses set by set_ref_status_for_push() */
 757                 switch (ref->status) {
 758                 case REF_STATUS_REJECT_NONFASTFORWARD:
 759                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 760                 case REF_STATUS_UPTODATE:
 761                         continue;
 762                 default:
 763                         ; /* do nothing */
 764                 }
 765
 766                 if (force_all)
 767                         ref->force = 1;
 768
 769                 strbuf_addstr(&buf, "push ");
 770                 if (!ref->deletion) {
 771                         if (ref->force)
 772                                 strbuf_addch(&buf, '+');
 773                         if (ref->peer_ref)
 774                                 strbuf_addstr(&buf, ref->peer_ref->name);
 775                         else
 776                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 777                 }
 778                 strbuf_addch(&buf, ':');
 779                 strbuf_addstr(&buf, ref->name);
 780                 strbuf_addch(&buf, '\n');
 781         }
 782         if (buf.len == 0)
 783                 return 0;
 784
 785         standard_options(transport);
 786
 787         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 788                 if (set_helper_option(transport, "dry-run", "true") != 0)
 789                         die("helper %s does not support dry-run", data->name);
 790         }
 791
 792         strbuf_addch(&buf, '\n');
 793         sendline(data, &buf);
 794         strbuf_release(&buf);
 795
 796         push_update_refs_status(data, remote_refs);
 797         return 0;
 798 }
 799
 800 static int push_refs_with_export(struct transport *transport,
 801                 struct ref *remote_refs, int flags)
 802 {
 803         struct ref *ref;
 804         struct child_process *helper, exporter;
 805         struct helper_data *data = transport->data;
 806         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 807         struct strbuf buf = STRBUF_INIT;
 808
 809         if (!data->refspecs)
 810                 die("remote-helper doesn't support push; refspec needed");
 811
 812         helper = get_helper(transport);
 813
 814         write_constant(helper->in, "export\n");
 815
 816         strbuf_reset(&buf);
 817
 818         for (ref = remote_refs; ref; ref = ref->next) {
 819                 char *private;
 820                 unsigned char sha1[20];
 821
 822                 if (ref->deletion)
 823                         die("remote-helpers do not support ref deletion");
 824
 825                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 826                 if (private && !get_sha1(private, sha1)) {
 827                         strbuf_addf(&buf, "^%s", private);
 828                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 829                         hashcpy(ref->old_sha1, sha1);
 830                 }
 831                 free(private);
 832
 833                 if (ref->peer_ref)
 834                         string_list_append(&revlist_args, ref->peer_ref->name);
 835         }
 836
 837         if (get_exporter(transport, &exporter, &revlist_args))
 838                 die("Couldn't run fast-export");
 839
 840         if (finish_command(&exporter))
 841                 die("Error while running fast-export");
 842         push_update_refs_status(data, remote_refs);
 843         return 0;
 844 }
 845
 846 static int push_refs(struct transport *transport,
 847                 struct ref *remote_refs, int flags)
 848 {
 849         struct helper_data *data = transport->data;
 850
 851         if (process_connect(transport, 1)) {
 852                 do_take_over(transport);
 853                 return transport->push_refs(transport, remote_refs, flags);
 854         }
 855
 856         if (!remote_refs) {
 857                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 858                         "Perhaps you should specify a branch such as 'master'.\n");
 859                 return 0;
 860         }
 861
 862         if (data->push)
 863                 return push_refs_with_push(transport, remote_refs, flags);
 864
 865         if (data->export)
 866                 return push_refs_with_export(transport, remote_refs, flags);
 867
 868         return -1;
 869 }
 870
 871
 872 static int has_attribute(const char *attrs, const char *attr) {
 873         int len;
 874         if (!attrs)
 875                 return 0;
 876
 877         len = strlen(attr);
 878         for (;;) {
 879                 const char *space = strchrnul(attrs, ' ');
 880                 if (len == space - attrs && !strncmp(attrs, attr, len))
 881                         return 1;
 882                 if (!*space)
 883                         return 0;
 884                 attrs = space + 1;
 885         }
 886 }
 887
 888 static struct ref *get_refs_list(struct transport *transport, int for_push)
 889 {
 890         struct helper_data *data = transport->data;
 891         struct child_process *helper;
 892         struct ref *ret = NULL;
 893         struct ref **tail = &ret;
 894         struct ref *posn;
 895         struct strbuf buf = STRBUF_INIT;
 896
 897         helper = get_helper(transport);
 898
 899         if (process_connect(transport, for_push)) {
 900                 do_take_over(transport);
 901                 return transport->get_refs_list(transport, for_push);
 902         }
 903
 904         if (data->push && for_push)
 905                 write_str_in_full(helper->in, "list for-push\n");
 906         else
 907                 write_str_in_full(helper->in, "list\n");
 908
 909         while (1) {
 910                 char *eov, *eon;
 911                 recvline(data, &buf);
 912
 913                 if (!*buf.buf)
 914                         break;
 915
 916                 eov = strchr(buf.buf, ' ');
 917                 if (!eov)
 918                         die("Malformed response in ref list: %s", buf.buf);
 919                 eon = strchr(eov + 1, ' ');
 920                 *eov = '\0';
 921                 if (eon)
 922                         *eon = '\0';
 923                 *tail = alloc_ref(eov + 1);
 924                 if (buf.buf[0] == '@')
 925                         (*tail)->symref = xstrdup(buf.buf + 1);
 926                 else if (buf.buf[0] != '?')
 927                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 928                 if (eon) {
 929                         if (has_attribute(eon + 1, "unchanged")) {
 930                                 (*tail)->status |= REF_STATUS_UPTODATE;
 931                                 read_ref((*tail)->name, (*tail)->old_sha1);
 932                         }
 933                 }
 934                 tail = &((*tail)->next);
 935         }
 936         if (debug)
 937                 fprintf(stderr, "Debug: Read ref listing.\n");
 938         strbuf_release(&buf);
 939
 940         for (posn = ret; posn; posn = posn->next)
 941                 resolve_remote_symref(posn, ret);
 942
 943         return ret;
 944 }
 945
 946 int transport_helper_init(struct transport *transport, const char *name)
 947 {
 948         struct helper_data *data = xcalloc(sizeof(*data), 1);
 949         data->name = name;
 950
 951         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 952                 debug = 1;
 953
 954         transport->data = data;
 955         transport->set_option = set_helper_option;
 956         transport->get_refs_list = get_refs_list;
 957         transport->fetch = fetch;
 958         transport->push_refs = push_refs;
 959         transport->disconnect = release_helper;
 960         transport->connect = connect_helper;
 961         transport->smart_options = &(data->transport_options);
 962         return 0;
 963 }
 964
 965 /*
 966  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 967  * buffer less), so attempt reads and writes with up to that size.
 968  */
 969 #define BUFFERSIZE 65536
 970 /* This should be enough to hold debugging message. */
 971 #define PBUFFERSIZE 8192
 972
 973 /* Print bidirectional transfer loop debug message. */
 974 static void transfer_debug(const char *fmt, ...)
 975 {
 976         va_list args;
 977         char msgbuf[PBUFFERSIZE];
 978         static int debug_enabled = -1;
 979
 980         if (debug_enabled < 0)
 981                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 982         if (!debug_enabled)
 983                 return;
 984
 985         va_start(args, fmt);
 986         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 987         va_end(args);
 988         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 989 }
 990
 991 /* Stream state: More data may be coming in this direction. */
 992 #define SSTATE_TRANSFERING 0
 993 /*
 994  * Stream state: No more data coming in this direction, flushing rest of
 995  * data.
 996  */
 997 #define SSTATE_FLUSHING 1
 998 /* Stream state: Transfer in this direction finished. */
 999 #define SSTATE_FINISHED 2
1000
1001 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1002 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1003 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1004
1005 /* Unidirectional transfer. */
1006 struct unidirectional_transfer {
1007         /* Source */
1008         int src;
1009         /* Destination */
1010         int dest;
1011         /* Is source socket? */
1012         int src_is_sock;
1013         /* Is destination socket? */
1014         int dest_is_sock;
1015         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1016         int state;
1017         /* Buffer. */
1018         char buf[BUFFERSIZE];
1019         /* Buffer used. */
1020         size_t bufuse;
1021         /* Name of source. */
1022         const char *src_name;
1023         /* Name of destination. */
1024         const char *dest_name;
1025 };
1026
1027 /* Closes the target (for writing) if transfer has finished. */
1028 static void udt_close_if_finished(struct unidirectional_transfer *t)
1029 {
1030         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1031                 t->state = SSTATE_FINISHED;
1032                 if (t->dest_is_sock)
1033                         shutdown(t->dest, SHUT_WR);
1034                 else
1035                         close(t->dest);
1036                 transfer_debug("Closed %s.", t->dest_name);
1037         }
1038 }
1039
1040 /*
1041  * Tries to read read data from source into buffer. If buffer is full,
1042  * no data is read. Returns 0 on success, -1 on error.
1043  */
1044 static int udt_do_read(struct unidirectional_transfer *t)
1045 {
1046         ssize_t bytes;
1047
1048         if (t->bufuse == BUFFERSIZE)
1049                 return 0;       /* No space for more. */
1050
1051         transfer_debug("%s is readable", t->src_name);
1052         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1053         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1054                 errno != EINTR) {
1055                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1056                 return -1;
1057         } else if (bytes == 0) {
1058                 transfer_debug("%s EOF (with %i bytes in buffer)",
1059                         t->src_name, t->bufuse);
1060                 t->state = SSTATE_FLUSHING;
1061         } else if (bytes > 0) {
1062                 t->bufuse += bytes;
1063                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1064                         (int)bytes, t->src_name, (int)t->bufuse);
1065         }
1066         return 0;
1067 }
1068
1069 /* Tries to write data from buffer into destination. If buffer is empty,
1070  * no data is written. Returns 0 on success, -1 on error.
1071  */
1072 static int udt_do_write(struct unidirectional_transfer *t)
1073 {
1074         ssize_t bytes;
1075
1076         if (t->bufuse == 0)
1077                 return 0;       /* Nothing to write. */
1078
1079         transfer_debug("%s is writable", t->dest_name);
1080         bytes = write(t->dest, t->buf, t->bufuse);
1081         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1082                 errno != EINTR) {
1083                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1084                 return -1;
1085         } else if (bytes > 0) {
1086                 t->bufuse -= bytes;
1087                 if (t->bufuse)
1088                         memmove(t->buf, t->buf + bytes, t->bufuse);
1089                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1090                         (int)bytes, t->dest_name, (int)t->bufuse);
1091         }
1092         return 0;
1093 }
1094
1095
1096 /* State of bidirectional transfer loop. */
1097 struct bidirectional_transfer_state {
1098         /* Direction from program to git. */
1099         struct unidirectional_transfer ptg;
1100         /* Direction from git to program. */
1101         struct unidirectional_transfer gtp;
1102 };
1103
1104 static void *udt_copy_task_routine(void *udt)
1105 {
1106         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1107         while (t->state != SSTATE_FINISHED) {
1108                 if (STATE_NEEDS_READING(t->state))
1109                         if (udt_do_read(t))
1110                                 return NULL;
1111                 if (STATE_NEEDS_WRITING(t->state))
1112                         if (udt_do_write(t))
1113                                 return NULL;
1114                 if (STATE_NEEDS_CLOSING(t->state))
1115                         udt_close_if_finished(t);
1116         }
1117         return udt;     /* Just some non-NULL value. */
1118 }
1119
1120 #ifndef NO_PTHREADS
1121
1122 /*
1123  * Join thread, with apporiate errors on failure. Name is name for the
1124  * thread (for error messages). Returns 0 on success, 1 on failure.
1125  */
1126 static int tloop_join(pthread_t thread, const char *name)
1127 {
1128         int err;
1129         void *tret;
1130         err = pthread_join(thread, &tret);
1131         if (!tret) {
1132                 error("%s thread failed", name);
1133                 return 1;
1134         }
1135         if (err) {
1136                 error("%s thread failed to join: %s", name, strerror(err));
1137                 return 1;
1138         }
1139         return 0;
1140 }
1141
1142 /*
1143  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1144  * -1 on failure.
1145  */
1146 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1147 {
1148         pthread_t gtp_thread;
1149         pthread_t ptg_thread;
1150         int err;
1151         int ret = 0;
1152         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1153                 &s->gtp);
1154         if (err)
1155                 die("Can't start thread for copying data: %s", strerror(err));
1156         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1157                 &s->ptg);
1158         if (err)
1159                 die("Can't start thread for copying data: %s", strerror(err));
1160
1161         ret |= tloop_join(gtp_thread, "Git to program copy");
1162         ret |= tloop_join(ptg_thread, "Program to git copy");
1163         return ret;
1164 }
1165 #else
1166
1167 /* Close the source and target (for writing) for transfer. */
1168 static void udt_kill_transfer(struct unidirectional_transfer *t)
1169 {
1170         t->state = SSTATE_FINISHED;
1171         /*
1172          * Socket read end left open isn't a disaster if nobody
1173          * attempts to read from it (mingw compat headers do not
1174          * have SHUT_RD)...
1175          *
1176          * We can't fully close the socket since otherwise gtp
1177          * task would first close the socket it sends data to
1178          * while closing the ptg file descriptors.
1179          */
1180         if (!t->src_is_sock)
1181                 close(t->src);
1182         if (t->dest_is_sock)
1183                 shutdown(t->dest, SHUT_WR);
1184         else
1185                 close(t->dest);
1186 }
1187
1188 /*
1189  * Join process, with apporiate errors on failure. Name is name for the
1190  * process (for error messages). Returns 0 on success, 1 on failure.
1191  */
1192 static int tloop_join(pid_t pid, const char *name)
1193 {
1194         int tret;
1195         if (waitpid(pid, &tret, 0) < 0) {
1196                 error("%s process failed to wait: %s", name, strerror(errno));
1197                 return 1;
1198         }
1199         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1200                 error("%s process failed", name);
1201                 return 1;
1202         }
1203         return 0;
1204 }
1205
1206 /*
1207  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1208  * -1 on failure.
1209  */
1210 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1211 {
1212         pid_t pid1, pid2;
1213         int ret = 0;
1214
1215         /* Fork thread #1: git to program. */
1216         pid1 = fork();
1217         if (pid1 < 0)
1218                 die_errno("Can't start thread for copying data");
1219         else if (pid1 == 0) {
1220                 udt_kill_transfer(&s->ptg);
1221                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1222         }
1223
1224         /* Fork thread #2: program to git. */
1225         pid2 = fork();
1226         if (pid2 < 0)
1227                 die_errno("Can't start thread for copying data");
1228         else if (pid2 == 0) {
1229                 udt_kill_transfer(&s->gtp);
1230                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1231         }
1232
1233         /*
1234          * Close both streams in parent as to not interfere with
1235          * end of file detection and wait for both tasks to finish.
1236          */
1237         udt_kill_transfer(&s->gtp);
1238         udt_kill_transfer(&s->ptg);
1239         ret |= tloop_join(pid1, "Git to program copy");
1240         ret |= tloop_join(pid2, "Program to git copy");
1241         return ret;
1242 }
1243 #endif
1244
1245 /*
1246  * Copies data from stdin to output and from input to stdout simultaneously.
1247  * Additionally filtering through given filter. If filter is NULL, uses
1248  * identity filter.
1249  */
1250 int bidirectional_transfer_loop(int input, int output)
1251 {
1252         struct bidirectional_transfer_state state;
1253
1254         /* Fill the state fields. */
1255         state.ptg.src = input;
1256         state.ptg.dest = 1;
1257         state.ptg.src_is_sock = (input == output);
1258         state.ptg.dest_is_sock = 0;
1259         state.ptg.state = SSTATE_TRANSFERING;
1260         state.ptg.bufuse = 0;
1261         state.ptg.src_name = "remote input";
1262         state.ptg.dest_name = "stdout";
1263
1264         state.gtp.src = 0;
1265         state.gtp.dest = output;
1266         state.gtp.src_is_sock = 0;
1267         state.gtp.dest_is_sock = (input == output);
1268         state.gtp.state = SSTATE_TRANSFERING;
1269         state.gtp.bufuse = 0;
1270         state.gtp.src_name = "stdin";
1271         state.gtp.dest_name = "remote output";
1272
1273         return tloop_spawnwait_tasks(&state);
1274 }