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
  13 static int debug;
  14
  15 struct helper_data {
  16         const char *name;
  17         struct child_process *helper;
  18         FILE *out;
  19         unsigned fetch : 1,
  20                 import : 1,
  21                 export : 1,
  22                 option : 1,
  23                 push : 1,
  24                 connect : 1,
  25                 no_disconnect_req : 1;
  26         char *export_marks;
  27         char *import_marks;
  28         /* These go from remote name (as in "list") to private name */
  29         struct refspec *refspecs;
  30         int refspec_nr;
  31         /* Transport options for fetch-pack/send-pack (should one of
  32          * those be invoked).
  33          */
  34         struct git_transport_options transport_options;
  35 };
  36
  37 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  38 {
  39         if (debug)
  40                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  41         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  42                 != buffer->len)
  43                 die_errno("Full write to remote helper failed");
  44 }
  45
  46 static int recvline_fh(FILE *helper, struct strbuf *buffer)
  47 {
  48         strbuf_reset(buffer);
  49         if (debug)
  50                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  51         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  52                 if (debug)
  53                         fprintf(stderr, "Debug: Remote helper quit.\n");
  54                 exit(128);
  55         }
  56
  57         if (debug)
  58                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  59         return 0;
  60 }
  61
  62 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  63 {
  64         return recvline_fh(helper->out, buffer);
  65 }
  66
  67 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  68 {
  69         sendline(helper, buffer);
  70         recvline(helper, buffer);
  71 }
  72
  73 static void write_constant(int fd, const char *str)
  74 {
  75         if (debug)
  76                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  77         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  78                 die_errno("Full write to remote helper failed");
  79 }
  80
  81 static const char *remove_ext_force(const char *url)
  82 {
  83         if (url) {
  84                 const char *colon = strchr(url, ':');
  85                 if (colon && colon[1] == ':')
  86                         return colon + 2;
  87         }
  88         return url;
  89 }
  90
  91 static void do_take_over(struct transport *transport)
  92 {
  93         struct helper_data *data;
  94         data = (struct helper_data *)transport->data;
  95         transport_take_over(transport, data->helper);
  96         fclose(data->out);
  97         free(data);
  98 }
  99
 100 static struct child_process *get_helper(struct transport *transport)
 101 {
 102         struct helper_data *data = transport->data;
 103         struct strbuf buf = STRBUF_INIT;
 104         struct child_process *helper;
 105         const char **refspecs = NULL;
 106         int refspec_nr = 0;
 107         int refspec_alloc = 0;
 108         int duped;
 109         int code;
 110         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 111         const char *helper_env[] = {
 112                 git_dir_buf,
 113                 NULL
 114         };
 115
 116
 117         if (data->helper)
 118                 return data->helper;
 119
 120         helper = xcalloc(1, sizeof(*helper));
 121         helper->in = -1;
 122         helper->out = -1;
 123         helper->err = 0;
 124         helper->argv = xcalloc(4, sizeof(*helper->argv));
 125         strbuf_addf(&buf, "git-remote-%s", data->name);
 126         helper->argv[0] = strbuf_detach(&buf, NULL);
 127         helper->argv[1] = transport->remote->name;
 128         helper->argv[2] = remove_ext_force(transport->url);
 129         helper->git_cmd = 0;
 130         helper->silent_exec_failure = 1;
 131
 132         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 133         helper->env = helper_env;
 134
 135         code = start_command(helper);
 136         if (code < 0 && errno == ENOENT)
 137                 die("Unable to find remote helper for '%s'", data->name);
 138         else if (code != 0)
 139                 exit(code);
 140
 141         data->helper = helper;
 142         data->no_disconnect_req = 0;
 143
 144         /*
 145          * Open the output as FILE* so strbuf_getline() can be used.
 146          * Do this with duped fd because fclose() will close the fd,
 147          * and stuff like taking over will require the fd to remain.
 148          */
 149         duped = dup(helper->out);
 150         if (duped < 0)
 151                 die_errno("Can't dup helper output fd");
 152         data->out = xfdopen(duped, "r");
 153
 154         write_constant(helper->in, "capabilities\n");
 155
 156         while (1) {
 157                 const char *capname;
 158                 int mandatory = 0;
 159                 recvline(data, &buf);
 160
 161                 if (!*buf.buf)
 162                         break;
 163
 164                 if (*buf.buf == '*') {
 165                         capname = buf.buf + 1;
 166                         mandatory = 1;
 167                 } else
 168                         capname = buf.buf;
 169
 170                 if (debug)
 171                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 172                 if (!strcmp(capname, "fetch"))
 173                         data->fetch = 1;
 174                 else if (!strcmp(capname, "option"))
 175                         data->option = 1;
 176                 else if (!strcmp(capname, "push"))
 177                         data->push = 1;
 178                 else if (!strcmp(capname, "import"))
 179                         data->import = 1;
 180                 else if (!strcmp(capname, "export"))
 181                         data->export = 1;
 182                 else if (!data->refspecs && !prefixcmp(capname, "refspec ")) {
 183                         ALLOC_GROW(refspecs,
 184                                    refspec_nr + 1,
 185                                    refspec_alloc);
 186                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 187                 } else if (!strcmp(capname, "connect")) {
 188                         data->connect = 1;
 189                 } else if (!prefixcmp(capname, "export-marks ")) {
 190                         struct strbuf arg = STRBUF_INIT;
 191                         strbuf_addstr(&arg, "--export-marks=");
 192                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 193                         data->export_marks = strbuf_detach(&arg, NULL);
 194                 } else if (!prefixcmp(capname, "import-marks")) {
 195                         struct strbuf arg = STRBUF_INIT;
 196                         strbuf_addstr(&arg, "--import-marks=");
 197                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 198                         data->import_marks = strbuf_detach(&arg, NULL);
 199                 } else if (mandatory) {
 200                         die("Unknown mandatory capability %s. This remote "
 201                             "helper probably needs newer version of Git.\n",
 202                             capname);
 203                 }
 204         }
 205         if (refspecs) {
 206                 int i;
 207                 data->refspec_nr = refspec_nr;
 208                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 209                 for (i = 0; i < refspec_nr; i++) {
 210                         free((char *)refspecs[i]);
 211                 }
 212                 free(refspecs);
 213         }
 214         strbuf_release(&buf);
 215         if (debug)
 216                 fprintf(stderr, "Debug: Capabilities complete.\n");
 217         return data->helper;
 218 }
 219
 220 static int disconnect_helper(struct transport *transport)
 221 {
 222         struct helper_data *data = transport->data;
 223         struct strbuf buf = STRBUF_INIT;
 224         int res = 0;
 225
 226         if (data->helper) {
 227                 if (debug)
 228                         fprintf(stderr, "Debug: Disconnecting.\n");
 229                 if (!data->no_disconnect_req) {
 230                         strbuf_addf(&buf, "\n");
 231                         sendline(data, &buf);
 232                 }
 233                 close(data->helper->in);
 234                 close(data->helper->out);
 235                 fclose(data->out);
 236                 res = finish_command(data->helper);
 237                 free((char *)data->helper->argv[0]);
 238                 free(data->helper->argv);
 239                 free(data->helper);
 240                 data->helper = NULL;
 241         }
 242         return res;
 243 }
 244
 245 static const char *unsupported_options[] = {
 246         TRANS_OPT_UPLOADPACK,
 247         TRANS_OPT_RECEIVEPACK,
 248         TRANS_OPT_THIN,
 249         TRANS_OPT_KEEP
 250         };
 251 static const char *boolean_options[] = {
 252         TRANS_OPT_THIN,
 253         TRANS_OPT_KEEP,
 254         TRANS_OPT_FOLLOWTAGS
 255         };
 256
 257 static int set_helper_option(struct transport *transport,
 258                           const char *name, const char *value)
 259 {
 260         struct helper_data *data = transport->data;
 261         struct strbuf buf = STRBUF_INIT;
 262         int i, ret, is_bool = 0;
 263
 264         get_helper(transport);
 265
 266         if (!data->option)
 267                 return 1;
 268
 269         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 270                 if (!strcmp(name, unsupported_options[i]))
 271                         return 1;
 272         }
 273
 274         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 275                 if (!strcmp(name, boolean_options[i])) {
 276                         is_bool = 1;
 277                         break;
 278                 }
 279         }
 280
 281         strbuf_addf(&buf, "option %s ", name);
 282         if (is_bool)
 283                 strbuf_addstr(&buf, value ? "true" : "false");
 284         else
 285                 quote_c_style(value, &buf, NULL, 0);
 286         strbuf_addch(&buf, '\n');
 287
 288         xchgline(data, &buf);
 289
 290         if (!strcmp(buf.buf, "ok"))
 291                 ret = 0;
 292         else if (!prefixcmp(buf.buf, "error")) {
 293                 ret = -1;
 294         } else if (!strcmp(buf.buf, "unsupported"))
 295                 ret = 1;
 296         else {
 297                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 298                 ret = 1;
 299         }
 300         strbuf_release(&buf);
 301         return ret;
 302 }
 303
 304 static void standard_options(struct transport *t)
 305 {
 306         char buf[16];
 307         int n;
 308         int v = t->verbose;
 309
 310         set_helper_option(t, "progress", t->progress ? "true" : "false");
 311
 312         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 313         if (n >= sizeof(buf))
 314                 die("impossibly large verbosity value");
 315         set_helper_option(t, "verbosity", buf);
 316 }
 317
 318 static int release_helper(struct transport *transport)
 319 {
 320         int res = 0;
 321         struct helper_data *data = transport->data;
 322         free_refspec(data->refspec_nr, data->refspecs);
 323         data->refspecs = NULL;
 324         res = disconnect_helper(transport);
 325         free(transport->data);
 326         return res;
 327 }
 328
 329 static int fetch_with_fetch(struct transport *transport,
 330                             int nr_heads, struct ref **to_fetch)
 331 {
 332         struct helper_data *data = transport->data;
 333         int i;
 334         struct strbuf buf = STRBUF_INIT;
 335
 336         standard_options(transport);
 337
 338         for (i = 0; i < nr_heads; i++) {
 339                 const struct ref *posn = to_fetch[i];
 340                 if (posn->status & REF_STATUS_UPTODATE)
 341                         continue;
 342
 343                 strbuf_addf(&buf, "fetch %s %s\n",
 344                             sha1_to_hex(posn->old_sha1), posn->name);
 345         }
 346
 347         strbuf_addch(&buf, '\n');
 348         sendline(data, &buf);
 349
 350         while (1) {
 351                 recvline(data, &buf);
 352
 353                 if (!prefixcmp(buf.buf, "lock ")) {
 354                         const char *name = buf.buf + 5;
 355                         if (transport->pack_lockfile)
 356                                 warning("%s also locked %s", data->name, name);
 357                         else
 358                                 transport->pack_lockfile = xstrdup(name);
 359                 }
 360                 else if (!buf.len)
 361                         break;
 362                 else
 363                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 364         }
 365         strbuf_release(&buf);
 366         return 0;
 367 }
 368
 369 static int get_importer(struct transport *transport, struct child_process *fastimport)
 370 {
 371         struct child_process *helper = get_helper(transport);
 372         memset(fastimport, 0, sizeof(*fastimport));
 373         fastimport->in = helper->out;
 374         fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
 375         fastimport->argv[0] = "fast-import";
 376         fastimport->argv[1] = "--quiet";
 377
 378         fastimport->git_cmd = 1;
 379         return start_command(fastimport);
 380 }
 381
 382 static int get_exporter(struct transport *transport,
 383                         struct child_process *fastexport,
 384                         struct string_list *revlist_args)
 385 {
 386         struct helper_data *data = transport->data;
 387         struct child_process *helper = get_helper(transport);
 388         int argc = 0, i;
 389         memset(fastexport, 0, sizeof(*fastexport));
 390
 391         /* we need to duplicate helper->in because we want to use it after
 392          * fastexport is done with it. */
 393         fastexport->out = dup(helper->in);
 394         fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
 395         fastexport->argv[argc++] = "fast-export";
 396         fastexport->argv[argc++] = "--use-done-feature";
 397         if (data->export_marks)
 398                 fastexport->argv[argc++] = data->export_marks;
 399         if (data->import_marks)
 400                 fastexport->argv[argc++] = data->import_marks;
 401
 402         for (i = 0; i < revlist_args->nr; i++)
 403                 fastexport->argv[argc++] = revlist_args->items[i].string;
 404
 405         fastexport->git_cmd = 1;
 406         return start_command(fastexport);
 407 }
 408
 409 static int fetch_with_import(struct transport *transport,
 410                              int nr_heads, struct ref **to_fetch)
 411 {
 412         struct child_process fastimport;
 413         struct helper_data *data = transport->data;
 414         int i;
 415         struct ref *posn;
 416         struct strbuf buf = STRBUF_INIT;
 417
 418         get_helper(transport);
 419
 420         if (get_importer(transport, &fastimport))
 421                 die("Couldn't run fast-import");
 422
 423         for (i = 0; i < nr_heads; i++) {
 424                 posn = to_fetch[i];
 425                 if (posn->status & REF_STATUS_UPTODATE)
 426                         continue;
 427
 428                 strbuf_addf(&buf, "import %s\n", posn->name);
 429                 sendline(data, &buf);
 430                 strbuf_reset(&buf);
 431         }
 432
 433         write_constant(data->helper->in, "\n");
 434
 435         if (finish_command(&fastimport))
 436                 die("Error while running fast-import");
 437         free(fastimport.argv);
 438         fastimport.argv = NULL;
 439
 440         for (i = 0; i < nr_heads; i++) {
 441                 char *private;
 442                 posn = to_fetch[i];
 443                 if (posn->status & REF_STATUS_UPTODATE)
 444                         continue;
 445                 if (data->refspecs)
 446                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 447                 else
 448                         private = xstrdup(posn->name);
 449                 read_ref(private, posn->old_sha1);
 450                 free(private);
 451         }
 452         strbuf_release(&buf);
 453         return 0;
 454 }
 455
 456 static int process_connect_service(struct transport *transport,
 457                                    const char *name, const char *exec)
 458 {
 459         struct helper_data *data = transport->data;
 460         struct strbuf cmdbuf = STRBUF_INIT;
 461         struct child_process *helper;
 462         int r, duped, ret = 0;
 463         FILE *input;
 464
 465         helper = get_helper(transport);
 466
 467         /*
 468          * Yes, dup the pipe another time, as we need unbuffered version
 469          * of input pipe as FILE*. fclose() closes the underlying fd and
 470          * stream buffering only can be changed before first I/O operation
 471          * on it.
 472          */
 473         duped = dup(helper->out);
 474         if (duped < 0)
 475                 die_errno("Can't dup helper output fd");
 476         input = xfdopen(duped, "r");
 477         setvbuf(input, NULL, _IONBF, 0);
 478
 479         /*
 480          * Handle --upload-pack and friends. This is fire and forget...
 481          * just warn if it fails.
 482          */
 483         if (strcmp(name, exec)) {
 484                 r = set_helper_option(transport, "servpath", exec);
 485                 if (r > 0)
 486                         warning("Setting remote service path not supported by protocol.");
 487                 else if (r < 0)
 488                         warning("Invalid remote service path.");
 489         }
 490
 491         if (data->connect)
 492                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 493         else
 494                 goto exit;
 495
 496         sendline(data, &cmdbuf);
 497         recvline_fh(input, &cmdbuf);
 498         if (!strcmp(cmdbuf.buf, "")) {
 499                 data->no_disconnect_req = 1;
 500                 if (debug)
 501                         fprintf(stderr, "Debug: Smart transport connection "
 502                                 "ready.\n");
 503                 ret = 1;
 504         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 505                 if (debug)
 506                         fprintf(stderr, "Debug: Falling back to dumb "
 507                                 "transport.\n");
 508         } else
 509                 die("Unknown response to connect: %s",
 510                         cmdbuf.buf);
 511
 512 exit:
 513         fclose(input);
 514         return ret;
 515 }
 516
 517 static int process_connect(struct transport *transport,
 518                                      int for_push)
 519 {
 520         struct helper_data *data = transport->data;
 521         const char *name;
 522         const char *exec;
 523
 524         name = for_push ? "git-receive-pack" : "git-upload-pack";
 525         if (for_push)
 526                 exec = data->transport_options.receivepack;
 527         else
 528                 exec = data->transport_options.uploadpack;
 529
 530         return process_connect_service(transport, name, exec);
 531 }
 532
 533 static int connect_helper(struct transport *transport, const char *name,
 534                    const char *exec, int fd[2])
 535 {
 536         struct helper_data *data = transport->data;
 537
 538         /* Get_helper so connect is inited. */
 539         get_helper(transport);
 540         if (!data->connect)
 541                 die("Operation not supported by protocol.");
 542
 543         if (!process_connect_service(transport, name, exec))
 544                 die("Can't connect to subservice %s.", name);
 545
 546         fd[0] = data->helper->out;
 547         fd[1] = data->helper->in;
 548         return 0;
 549 }
 550
 551 static int fetch(struct transport *transport,
 552                  int nr_heads, struct ref **to_fetch)
 553 {
 554         struct helper_data *data = transport->data;
 555         int i, count;
 556
 557         if (process_connect(transport, 0)) {
 558                 do_take_over(transport);
 559                 return transport->fetch(transport, nr_heads, to_fetch);
 560         }
 561
 562         count = 0;
 563         for (i = 0; i < nr_heads; i++)
 564                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 565                         count++;
 566
 567         if (!count)
 568                 return 0;
 569
 570         if (data->fetch)
 571                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 572
 573         if (data->import)
 574                 return fetch_with_import(transport, nr_heads, to_fetch);
 575
 576         return -1;
 577 }
 578
 579 static void push_update_ref_status(struct strbuf *buf,
 580                                    struct ref **ref,
 581                                    struct ref *remote_refs)
 582 {
 583         char *refname, *msg;
 584         int status;
 585
 586         if (!prefixcmp(buf->buf, "ok ")) {
 587                 status = REF_STATUS_OK;
 588                 refname = buf->buf + 3;
 589         } else if (!prefixcmp(buf->buf, "error ")) {
 590                 status = REF_STATUS_REMOTE_REJECT;
 591                 refname = buf->buf + 6;
 592         } else
 593                 die("expected ok/error, helper said '%s'\n", buf->buf);
 594
 595         msg = strchr(refname, ' ');
 596         if (msg) {
 597                 struct strbuf msg_buf = STRBUF_INIT;
 598                 const char *end;
 599
 600                 *msg++ = '\0';
 601                 if (!unquote_c_style(&msg_buf, msg, &end))
 602                         msg = strbuf_detach(&msg_buf, NULL);
 603                 else
 604                         msg = xstrdup(msg);
 605                 strbuf_release(&msg_buf);
 606
 607                 if (!strcmp(msg, "no match")) {
 608                         status = REF_STATUS_NONE;
 609                         free(msg);
 610                         msg = NULL;
 611                 }
 612                 else if (!strcmp(msg, "up to date")) {
 613                         status = REF_STATUS_UPTODATE;
 614                         free(msg);
 615                         msg = NULL;
 616                 }
 617                 else if (!strcmp(msg, "non-fast forward")) {
 618                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 619                         free(msg);
 620                         msg = NULL;
 621                 }
 622         }
 623
 624         if (*ref)
 625                 *ref = find_ref_by_name(*ref, refname);
 626         if (!*ref)
 627                 *ref = find_ref_by_name(remote_refs, refname);
 628         if (!*ref) {
 629                 warning("helper reported unexpected status of %s", refname);
 630                 return;
 631         }
 632
 633         if ((*ref)->status != REF_STATUS_NONE) {
 634                 /*
 635                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 636                  * status reported by the remote helper if the latter is 'no match'.
 637                  */
 638                 if (status == REF_STATUS_NONE)
 639                         return;
 640         }
 641
 642         (*ref)->status = status;
 643         (*ref)->remote_status = msg;
 644 }
 645
 646 static void push_update_refs_status(struct helper_data *data,
 647                                     struct ref *remote_refs)
 648 {
 649         struct strbuf buf = STRBUF_INIT;
 650         struct ref *ref = remote_refs;
 651         for (;;) {
 652                 recvline(data, &buf);
 653                 if (!buf.len)
 654                         break;
 655
 656                 push_update_ref_status(&buf, &ref, remote_refs);
 657         }
 658         strbuf_release(&buf);
 659 }
 660
 661 static int push_refs_with_push(struct transport *transport,
 662                 struct ref *remote_refs, int flags)
 663 {
 664         int force_all = flags & TRANSPORT_PUSH_FORCE;
 665         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 666         struct helper_data *data = transport->data;
 667         struct strbuf buf = STRBUF_INIT;
 668         struct ref *ref;
 669
 670         get_helper(transport);
 671         if (!data->push)
 672                 return 1;
 673
 674         for (ref = remote_refs; ref; ref = ref->next) {
 675                 if (!ref->peer_ref && !mirror)
 676                         continue;
 677
 678                 /* Check for statuses set by set_ref_status_for_push() */
 679                 switch (ref->status) {
 680                 case REF_STATUS_REJECT_NONFASTFORWARD:
 681                 case REF_STATUS_UPTODATE:
 682                         continue;
 683                 default:
 684                         ; /* do nothing */
 685                 }
 686
 687                 if (force_all)
 688                         ref->force = 1;
 689
 690                 strbuf_addstr(&buf, "push ");
 691                 if (!ref->deletion) {
 692                         if (ref->force)
 693                                 strbuf_addch(&buf, '+');
 694                         if (ref->peer_ref)
 695                                 strbuf_addstr(&buf, ref->peer_ref->name);
 696                         else
 697                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 698                 }
 699                 strbuf_addch(&buf, ':');
 700                 strbuf_addstr(&buf, ref->name);
 701                 strbuf_addch(&buf, '\n');
 702         }
 703         if (buf.len == 0)
 704                 return 0;
 705
 706         standard_options(transport);
 707
 708         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 709                 if (set_helper_option(transport, "dry-run", "true") != 0)
 710                         die("helper %s does not support dry-run", data->name);
 711         }
 712
 713         strbuf_addch(&buf, '\n');
 714         sendline(data, &buf);
 715         strbuf_release(&buf);
 716
 717         push_update_refs_status(data, remote_refs);
 718         return 0;
 719 }
 720
 721 static int push_refs_with_export(struct transport *transport,
 722                 struct ref *remote_refs, int flags)
 723 {
 724         struct ref *ref;
 725         struct child_process *helper, exporter;
 726         struct helper_data *data = transport->data;
 727         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 728         struct strbuf buf = STRBUF_INIT;
 729
 730         helper = get_helper(transport);
 731
 732         write_constant(helper->in, "export\n");
 733
 734         strbuf_reset(&buf);
 735
 736         for (ref = remote_refs; ref; ref = ref->next) {
 737                 char *private;
 738                 unsigned char sha1[20];
 739
 740                 if (!data->refspecs)
 741                         continue;
 742                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 743                 if (private && !get_sha1(private, sha1)) {
 744                         strbuf_addf(&buf, "^%s", private);
 745                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 746                 }
 747                 free(private);
 748
 749                 if (ref->deletion) {
 750                         die("remote-helpers do not support ref deletion");
 751                 }
 752
 753                 if (ref->peer_ref)
 754                         string_list_append(&revlist_args, ref->peer_ref->name);
 755
 756         }
 757
 758         if (get_exporter(transport, &exporter, &revlist_args))
 759                 die("Couldn't run fast-export");
 760
 761         if (finish_command(&exporter))
 762                 die("Error while running fast-export");
 763         push_update_refs_status(data, remote_refs);
 764         return 0;
 765 }
 766
 767 static int push_refs(struct transport *transport,
 768                 struct ref *remote_refs, int flags)
 769 {
 770         struct helper_data *data = transport->data;
 771
 772         if (process_connect(transport, 1)) {
 773                 do_take_over(transport);
 774                 return transport->push_refs(transport, remote_refs, flags);
 775         }
 776
 777         if (!remote_refs) {
 778                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 779                         "Perhaps you should specify a branch such as 'master'.\n");
 780                 return 0;
 781         }
 782
 783         if (data->push)
 784                 return push_refs_with_push(transport, remote_refs, flags);
 785
 786         if (data->export)
 787                 return push_refs_with_export(transport, remote_refs, flags);
 788
 789         return -1;
 790 }
 791
 792
 793 static int has_attribute(const char *attrs, const char *attr) {
 794         int len;
 795         if (!attrs)
 796                 return 0;
 797
 798         len = strlen(attr);
 799         for (;;) {
 800                 const char *space = strchrnul(attrs, ' ');
 801                 if (len == space - attrs && !strncmp(attrs, attr, len))
 802                         return 1;
 803                 if (!*space)
 804                         return 0;
 805                 attrs = space + 1;
 806         }
 807 }
 808
 809 static struct ref *get_refs_list(struct transport *transport, int for_push)
 810 {
 811         struct helper_data *data = transport->data;
 812         struct child_process *helper;
 813         struct ref *ret = NULL;
 814         struct ref **tail = &ret;
 815         struct ref *posn;
 816         struct strbuf buf = STRBUF_INIT;
 817
 818         helper = get_helper(transport);
 819
 820         if (process_connect(transport, for_push)) {
 821                 do_take_over(transport);
 822                 return transport->get_refs_list(transport, for_push);
 823         }
 824
 825         if (data->push && for_push)
 826                 write_str_in_full(helper->in, "list for-push\n");
 827         else
 828                 write_str_in_full(helper->in, "list\n");
 829
 830         while (1) {
 831                 char *eov, *eon;
 832                 recvline(data, &buf);
 833
 834                 if (!*buf.buf)
 835                         break;
 836
 837                 eov = strchr(buf.buf, ' ');
 838                 if (!eov)
 839                         die("Malformed response in ref list: %s", buf.buf);
 840                 eon = strchr(eov + 1, ' ');
 841                 *eov = '\0';
 842                 if (eon)
 843                         *eon = '\0';
 844                 *tail = alloc_ref(eov + 1);
 845                 if (buf.buf[0] == '@')
 846                         (*tail)->symref = xstrdup(buf.buf + 1);
 847                 else if (buf.buf[0] != '?')
 848                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 849                 if (eon) {
 850                         if (has_attribute(eon + 1, "unchanged")) {
 851                                 (*tail)->status |= REF_STATUS_UPTODATE;
 852                                 read_ref((*tail)->name, (*tail)->old_sha1);
 853                         }
 854                 }
 855                 tail = &((*tail)->next);
 856         }
 857         if (debug)
 858                 fprintf(stderr, "Debug: Read ref listing.\n");
 859         strbuf_release(&buf);
 860
 861         for (posn = ret; posn; posn = posn->next)
 862                 resolve_remote_symref(posn, ret);
 863
 864         return ret;
 865 }
 866
 867 int transport_helper_init(struct transport *transport, const char *name)
 868 {
 869         struct helper_data *data = xcalloc(sizeof(*data), 1);
 870         data->name = name;
 871
 872         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
 873                 debug = 1;
 874
 875         transport->data = data;
 876         transport->set_option = set_helper_option;
 877         transport->get_refs_list = get_refs_list;
 878         transport->fetch = fetch;
 879         transport->push_refs = push_refs;
 880         transport->disconnect = release_helper;
 881         transport->connect = connect_helper;
 882         transport->smart_options = &(data->transport_options);
 883         return 0;
 884 }
 885
 886 /*
 887  * Linux pipes can buffer 65536 bytes at once (and most platforms can
 888  * buffer less), so attempt reads and writes with up to that size.
 889  */
 890 #define BUFFERSIZE 65536
 891 /* This should be enough to hold debugging message. */
 892 #define PBUFFERSIZE 8192
 893
 894 /* Print bidirectional transfer loop debug message. */
 895 static void transfer_debug(const char *fmt, ...)
 896 {
 897         va_list args;
 898         char msgbuf[PBUFFERSIZE];
 899         static int debug_enabled = -1;
 900
 901         if (debug_enabled < 0)
 902                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
 903         if (!debug_enabled)
 904                 return;
 905
 906         va_start(args, fmt);
 907         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
 908         va_end(args);
 909         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
 910 }
 911
 912 /* Stream state: More data may be coming in this direction. */
 913 #define SSTATE_TRANSFERING 0
 914 /*
 915  * Stream state: No more data coming in this direction, flushing rest of
 916  * data.
 917  */
 918 #define SSTATE_FLUSHING 1
 919 /* Stream state: Transfer in this direction finished. */
 920 #define SSTATE_FINISHED 2
 921
 922 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
 923 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
 924 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
 925
 926 /* Unidirectional transfer. */
 927 struct unidirectional_transfer {
 928         /* Source */
 929         int src;
 930         /* Destination */
 931         int dest;
 932         /* Is source socket? */
 933         int src_is_sock;
 934         /* Is destination socket? */
 935         int dest_is_sock;
 936         /* Transfer state (TRANSFERING/FLUSHING/FINISHED) */
 937         int state;
 938         /* Buffer. */
 939         char buf[BUFFERSIZE];
 940         /* Buffer used. */
 941         size_t bufuse;
 942         /* Name of source. */
 943         const char *src_name;
 944         /* Name of destination. */
 945         const char *dest_name;
 946 };
 947
 948 /* Closes the target (for writing) if transfer has finished. */
 949 static void udt_close_if_finished(struct unidirectional_transfer *t)
 950 {
 951         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
 952                 t->state = SSTATE_FINISHED;
 953                 if (t->dest_is_sock)
 954                         shutdown(t->dest, SHUT_WR);
 955                 else
 956                         close(t->dest);
 957                 transfer_debug("Closed %s.", t->dest_name);
 958         }
 959 }
 960
 961 /*
 962  * Tries to read read data from source into buffer. If buffer is full,
 963  * no data is read. Returns 0 on success, -1 on error.
 964  */
 965 static int udt_do_read(struct unidirectional_transfer *t)
 966 {
 967         ssize_t bytes;
 968
 969         if (t->bufuse == BUFFERSIZE)
 970                 return 0;       /* No space for more. */
 971
 972         transfer_debug("%s is readable", t->src_name);
 973         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
 974         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
 975                 errno != EINTR) {
 976                 error("read(%s) failed: %s", t->src_name, strerror(errno));
 977                 return -1;
 978         } else if (bytes == 0) {
 979                 transfer_debug("%s EOF (with %i bytes in buffer)",
 980                         t->src_name, t->bufuse);
 981                 t->state = SSTATE_FLUSHING;
 982         } else if (bytes > 0) {
 983                 t->bufuse += bytes;
 984                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
 985                         (int)bytes, t->src_name, (int)t->bufuse);
 986         }
 987         return 0;
 988 }
 989
 990 /* Tries to write data from buffer into destination. If buffer is empty,
 991  * no data is written. Returns 0 on success, -1 on error.
 992  */
 993 static int udt_do_write(struct unidirectional_transfer *t)
 994 {
 995         ssize_t bytes;
 996
 997         if (t->bufuse == 0)
 998                 return 0;       /* Nothing to write. */
 999
1000         transfer_debug("%s is writable", t->dest_name);
1001         bytes = write(t->dest, t->buf, t->bufuse);
1002         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1003                 errno != EINTR) {
1004                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1005                 return -1;
1006         } else if (bytes > 0) {
1007                 t->bufuse -= bytes;
1008                 if (t->bufuse)
1009                         memmove(t->buf, t->buf + bytes, t->bufuse);
1010                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1011                         (int)bytes, t->dest_name, (int)t->bufuse);
1012         }
1013         return 0;
1014 }
1015
1016
1017 /* State of bidirectional transfer loop. */
1018 struct bidirectional_transfer_state {
1019         /* Direction from program to git. */
1020         struct unidirectional_transfer ptg;
1021         /* Direction from git to program. */
1022         struct unidirectional_transfer gtp;
1023 };
1024
1025 static void *udt_copy_task_routine(void *udt)
1026 {
1027         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1028         while (t->state != SSTATE_FINISHED) {
1029                 if (STATE_NEEDS_READING(t->state))
1030                         if (udt_do_read(t))
1031                                 return NULL;
1032                 if (STATE_NEEDS_WRITING(t->state))
1033                         if (udt_do_write(t))
1034                                 return NULL;
1035                 if (STATE_NEEDS_CLOSING(t->state))
1036                         udt_close_if_finished(t);
1037         }
1038         return udt;     /* Just some non-NULL value. */
1039 }
1040
1041 #ifndef NO_PTHREADS
1042
1043 /*
1044  * Join thread, with apporiate errors on failure. Name is name for the
1045  * thread (for error messages). Returns 0 on success, 1 on failure.
1046  */
1047 static int tloop_join(pthread_t thread, const char *name)
1048 {
1049         int err;
1050         void *tret;
1051         err = pthread_join(thread, &tret);
1052         if (!tret) {
1053                 error("%s thread failed", name);
1054                 return 1;
1055         }
1056         if (err) {
1057                 error("%s thread failed to join: %s", name, strerror(err));
1058                 return 1;
1059         }
1060         return 0;
1061 }
1062
1063 /*
1064  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1065  * -1 on failure.
1066  */
1067 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1068 {
1069         pthread_t gtp_thread;
1070         pthread_t ptg_thread;
1071         int err;
1072         int ret = 0;
1073         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1074                 &s->gtp);
1075         if (err)
1076                 die("Can't start thread for copying data: %s", strerror(err));
1077         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1078                 &s->ptg);
1079         if (err)
1080                 die("Can't start thread for copying data: %s", strerror(err));
1081
1082         ret |= tloop_join(gtp_thread, "Git to program copy");
1083         ret |= tloop_join(ptg_thread, "Program to git copy");
1084         return ret;
1085 }
1086 #else
1087
1088 /* Close the source and target (for writing) for transfer. */
1089 static void udt_kill_transfer(struct unidirectional_transfer *t)
1090 {
1091         t->state = SSTATE_FINISHED;
1092         /*
1093          * Socket read end left open isn't a disaster if nobody
1094          * attempts to read from it (mingw compat headers do not
1095          * have SHUT_RD)...
1096          *
1097          * We can't fully close the socket since otherwise gtp
1098          * task would first close the socket it sends data to
1099          * while closing the ptg file descriptors.
1100          */
1101         if (!t->src_is_sock)
1102                 close(t->src);
1103         if (t->dest_is_sock)
1104                 shutdown(t->dest, SHUT_WR);
1105         else
1106                 close(t->dest);
1107 }
1108
1109 /*
1110  * Join process, with apporiate errors on failure. Name is name for the
1111  * process (for error messages). Returns 0 on success, 1 on failure.
1112  */
1113 static int tloop_join(pid_t pid, const char *name)
1114 {
1115         int tret;
1116         if (waitpid(pid, &tret, 0) < 0) {
1117                 error("%s process failed to wait: %s", name, strerror(errno));
1118                 return 1;
1119         }
1120         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1121                 error("%s process failed", name);
1122                 return 1;
1123         }
1124         return 0;
1125 }
1126
1127 /*
1128  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1129  * -1 on failure.
1130  */
1131 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1132 {
1133         pid_t pid1, pid2;
1134         int ret = 0;
1135
1136         /* Fork thread #1: git to program. */
1137         pid1 = fork();
1138         if (pid1 < 0)
1139                 die_errno("Can't start thread for copying data");
1140         else if (pid1 == 0) {
1141                 udt_kill_transfer(&s->ptg);
1142                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1143         }
1144
1145         /* Fork thread #2: program to git. */
1146         pid2 = fork();
1147         if (pid2 < 0)
1148                 die_errno("Can't start thread for copying data");
1149         else if (pid2 == 0) {
1150                 udt_kill_transfer(&s->gtp);
1151                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1152         }
1153
1154         /*
1155          * Close both streams in parent as to not interfere with
1156          * end of file detection and wait for both tasks to finish.
1157          */
1158         udt_kill_transfer(&s->gtp);
1159         udt_kill_transfer(&s->ptg);
1160         ret |= tloop_join(pid1, "Git to program copy");
1161         ret |= tloop_join(pid2, "Program to git copy");
1162         return ret;
1163 }
1164 #endif
1165
1166 /*
1167  * Copies data from stdin to output and from input to stdout simultaneously.
1168  * Additionally filtering through given filter. If filter is NULL, uses
1169  * identity filter.
1170  */
1171 int bidirectional_transfer_loop(int input, int output)
1172 {
1173         struct bidirectional_transfer_state state;
1174
1175         /* Fill the state fields. */
1176         state.ptg.src = input;
1177         state.ptg.dest = 1;
1178         state.ptg.src_is_sock = (input == output);
1179         state.ptg.dest_is_sock = 0;
1180         state.ptg.state = SSTATE_TRANSFERING;
1181         state.ptg.bufuse = 0;
1182         state.ptg.src_name = "remote input";
1183         state.ptg.dest_name = "stdout";
1184
1185         state.gtp.src = 0;
1186         state.gtp.dest = output;
1187         state.gtp.src_is_sock = 0;
1188         state.gtp.dest_is_sock = (input == output);
1189         state.gtp.state = SSTATE_TRANSFERING;
1190         state.gtp.bufuse = 0;
1191         state.gtp.src_name = "stdin";
1192         state.gtp.dest_name = "remote output";
1193
1194         return tloop_spawnwait_tasks(&state);
1195 }