git.oblomov.eu Git - git/blob - transport-helper.c

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "quote.h"
   9 #include "remote.h"
  10 #include "string-list.h"
  11 #include "thread-utils.h"
  12 #include "sigchain.h"
  13 #include "argv-array.h"
  14 #include "refs.h"
  15
  16 static int debug;
  17
  18 struct helper_data {
  19         const char *name;
  20         struct child_process *helper;
  21         FILE *out;
  22         unsigned fetch : 1,
  23                 import : 1,
  24                 bidi_import : 1,
  25                 export : 1,
  26                 option : 1,
  27                 push : 1,
  28                 connect : 1,
  29                 signed_tags : 1,
  30                 check_connectivity : 1,
  31                 no_disconnect_req : 1,
  32                 no_private_update : 1;
  33         char *export_marks;
  34         char *import_marks;
  35         /* These go from remote name (as in "list") to private name */
  36         struct refspec *refspecs;
  37         int refspec_nr;
  38         /* Transport options for fetch-pack/send-pack (should one of
  39          * those be invoked).
  40          */
  41         struct git_transport_options transport_options;
  42 };
  43
  44 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  45 {
  46         if (debug)
  47                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  48         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  49                 != buffer->len)
  50                 die_errno("Full write to remote helper failed");
  51 }
  52
  53 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  54 {
  55         strbuf_reset(buffer);
  56         if (debug)
  57                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  58         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  59                 if (debug)
  60                         fprintf(stderr, "Debug: Remote helper quit.\n");
  61                 return 1;
  62         }
  63
  64         if (debug)
  65                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  66         return 0;
  67 }
  68
  69 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  70 {
  71         return recvline_fh(helper->out, buffer, helper->name);
  72 }
  73
  74 static void write_constant(int fd, const char *str)
  75 {
  76         if (debug)
  77                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  78         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  79                 die_errno("Full write to remote helper failed");
  80 }
  81
  82 static const char *remove_ext_force(const char *url)
  83 {
  84         if (url) {
  85                 const char *colon = strchr(url, ':');
  86                 if (colon && colon[1] == ':')
  87                         return colon + 2;
  88         }
  89         return url;
  90 }
  91
  92 static void do_take_over(struct transport *transport)
  93 {
  94         struct helper_data *data;
  95         data = (struct helper_data *)transport->data;
  96         transport_take_over(transport, data->helper);
  97         fclose(data->out);
  98         free(data);
  99 }
 100
 101 static struct child_process *get_helper(struct transport *transport)
 102 {
 103         struct helper_data *data = transport->data;
 104         struct argv_array argv = ARGV_ARRAY_INIT;
 105         struct strbuf buf = STRBUF_INIT;
 106         struct child_process *helper;
 107         const char **refspecs = NULL;
 108         int refspec_nr = 0;
 109         int refspec_alloc = 0;
 110         int duped;
 111         int code;
 112         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 113         const char *helper_env[] = {
 114                 git_dir_buf,
 115                 NULL
 116         };
 117
 118
 119         if (data->helper)
 120                 return data->helper;
 121
 122         helper = xcalloc(1, sizeof(*helper));
 123         helper->in = -1;
 124         helper->out = -1;
 125         helper->err = 0;
 126         argv_array_pushf(&argv, "git-remote-%s", data->name);
 127         argv_array_push(&argv, transport->remote->name);
 128         argv_array_push(&argv, remove_ext_force(transport->url));
 129         helper->argv = argv_array_detach(&argv, NULL);
 130         helper->git_cmd = 0;
 131         helper->silent_exec_failure = 1;
 132
 133         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 134         helper->env = helper_env;
 135
 136         code = start_command(helper);
 137         if (code < 0 && errno == ENOENT)
 138                 die("Unable to find remote helper for '%s'", data->name);
 139         else if (code != 0)
 140                 exit(code);
 141
 142         data->helper = helper;
 143         data->no_disconnect_req = 0;
 144
 145         /*
 146          * Open the output as FILE* so strbuf_getline() can be used.
 147          * Do this with duped fd because fclose() will close the fd,
 148          * and stuff like taking over will require the fd to remain.
 149          */
 150         duped = dup(helper->out);
 151         if (duped < 0)
 152                 die_errno("Can't dup helper output fd");
 153         data->out = xfdopen(duped, "r");
 154
 155         write_constant(helper->in, "capabilities\n");
 156
 157         while (1) {
 158                 const char *capname;
 159                 int mandatory = 0;
 160                 if (recvline(data, &buf))
 161                         exit(128);
 162
 163                 if (!*buf.buf)
 164                         break;
 165
 166                 if (*buf.buf == '*') {
 167                         capname = buf.buf + 1;
 168                         mandatory = 1;
 169                 } else
 170                         capname = buf.buf;
 171
 172                 if (debug)
 173                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 174                 if (!strcmp(capname, "fetch"))
 175                         data->fetch = 1;
 176                 else if (!strcmp(capname, "option"))
 177                         data->option = 1;
 178                 else if (!strcmp(capname, "push"))
 179                         data->push = 1;
 180                 else if (!strcmp(capname, "import"))
 181                         data->import = 1;
 182                 else if (!strcmp(capname, "bidi-import"))
 183                         data->bidi_import = 1;
 184                 else if (!strcmp(capname, "export"))
 185                         data->export = 1;
 186                 else if (!strcmp(capname, "check-connectivity"))
 187                         data->check_connectivity = 1;
 188                 else if (!data->refspecs && starts_with(capname, "refspec ")) {
 189                         ALLOC_GROW(refspecs,
 190                                    refspec_nr + 1,
 191                                    refspec_alloc);
 192                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 193                 } else if (!strcmp(capname, "connect")) {
 194                         data->connect = 1;
 195                 } else if (!strcmp(capname, "signed-tags")) {
 196                         data->signed_tags = 1;
 197                 } else if (starts_with(capname, "export-marks ")) {
 198                         struct strbuf arg = STRBUF_INIT;
 199                         strbuf_addstr(&arg, "--export-marks=");
 200                         strbuf_addstr(&arg, capname + strlen("export-marks "));
 201                         data->export_marks = strbuf_detach(&arg, NULL);
 202                 } else if (starts_with(capname, "import-marks")) {
 203                         struct strbuf arg = STRBUF_INIT;
 204                         strbuf_addstr(&arg, "--import-marks=");
 205                         strbuf_addstr(&arg, capname + strlen("import-marks "));
 206                         data->import_marks = strbuf_detach(&arg, NULL);
 207                 } else if (starts_with(capname, "no-private-update")) {
 208                         data->no_private_update = 1;
 209                 } else if (mandatory) {
 210                         die("Unknown mandatory capability %s. This remote "
 211                             "helper probably needs newer version of Git.",
 212                             capname);
 213                 }
 214         }
 215         if (refspecs) {
 216                 int i;
 217                 data->refspec_nr = refspec_nr;
 218                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 219                 for (i = 0; i < refspec_nr; i++)
 220                         free((char *)refspecs[i]);
 221                 free(refspecs);
 222         } else if (data->import || data->bidi_import || data->export) {
 223                 warning("This remote helper should implement refspec capability.");
 224         }
 225         strbuf_release(&buf);
 226         if (debug)
 227                 fprintf(stderr, "Debug: Capabilities complete.\n");
 228         return data->helper;
 229 }
 230
 231 static int disconnect_helper(struct transport *transport)
 232 {
 233         struct helper_data *data = transport->data;
 234         int res = 0;
 235
 236         if (data->helper) {
 237                 if (debug)
 238                         fprintf(stderr, "Debug: Disconnecting.\n");
 239                 if (!data->no_disconnect_req) {
 240                         /*
 241                          * Ignore write errors; there's nothing we can do,
 242                          * since we're about to close the pipe anyway. And the
 243                          * most likely error is EPIPE due to the helper dying
 244                          * to report an error itself.
 245                          */
 246                         sigchain_push(SIGPIPE, SIG_IGN);
 247                         xwrite(data->helper->in, "\n", 1);
 248                         sigchain_pop(SIGPIPE);
 249                 }
 250                 close(data->helper->in);
 251                 close(data->helper->out);
 252                 fclose(data->out);
 253                 res = finish_command(data->helper);
 254                 argv_array_free_detached(data->helper->argv);
 255                 free(data->helper);
 256                 data->helper = NULL;
 257         }
 258         return res;
 259 }
 260
 261 static const char *unsupported_options[] = {
 262         TRANS_OPT_UPLOADPACK,
 263         TRANS_OPT_RECEIVEPACK,
 264         TRANS_OPT_THIN,
 265         TRANS_OPT_KEEP
 266         };
 267
 268 static const char *boolean_options[] = {
 269         TRANS_OPT_THIN,
 270         TRANS_OPT_KEEP,
 271         TRANS_OPT_FOLLOWTAGS
 272         };
 273
 274 static int set_helper_option(struct transport *transport,
 275                           const char *name, const char *value)
 276 {
 277         struct helper_data *data = transport->data;
 278         struct strbuf buf = STRBUF_INIT;
 279         int i, ret, is_bool = 0;
 280
 281         get_helper(transport);
 282
 283         if (!data->option)
 284                 return 1;
 285
 286         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 287                 if (!strcmp(name, unsupported_options[i]))
 288                         return 1;
 289         }
 290
 291         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 292                 if (!strcmp(name, boolean_options[i])) {
 293                         is_bool = 1;
 294                         break;
 295                 }
 296         }
 297
 298         strbuf_addf(&buf, "option %s ", name);
 299         if (is_bool)
 300                 strbuf_addstr(&buf, value ? "true" : "false");
 301         else
 302                 quote_c_style(value, &buf, NULL, 0);
 303         strbuf_addch(&buf, '\n');
 304
 305         sendline(data, &buf);
 306         if (recvline(data, &buf))
 307                 exit(128);
 308
 309         if (!strcmp(buf.buf, "ok"))
 310                 ret = 0;
 311         else if (starts_with(buf.buf, "error")) {
 312                 ret = -1;
 313         } else if (!strcmp(buf.buf, "unsupported"))
 314                 ret = 1;
 315         else {
 316                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 317                 ret = 1;
 318         }
 319         strbuf_release(&buf);
 320         return ret;
 321 }
 322
 323 static void standard_options(struct transport *t)
 324 {
 325         char buf[16];
 326         int n;
 327         int v = t->verbose;
 328
 329         set_helper_option(t, "progress", t->progress ? "true" : "false");
 330
 331         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 332         if (n >= sizeof(buf))
 333                 die("impossibly large verbosity value");
 334         set_helper_option(t, "verbosity", buf);
 335 }
 336
 337 static int release_helper(struct transport *transport)
 338 {
 339         int res = 0;
 340         struct helper_data *data = transport->data;
 341         free_refspec(data->refspec_nr, data->refspecs);
 342         data->refspecs = NULL;
 343         res = disconnect_helper(transport);
 344         free(transport->data);
 345         return res;
 346 }
 347
 348 static int fetch_with_fetch(struct transport *transport,
 349                             int nr_heads, struct ref **to_fetch)
 350 {
 351         struct helper_data *data = transport->data;
 352         int i;
 353         struct strbuf buf = STRBUF_INIT;
 354
 355         standard_options(transport);
 356         if (data->check_connectivity &&
 357             data->transport_options.check_self_contained_and_connected)
 358                 set_helper_option(transport, "check-connectivity", "true");
 359
 360         if (transport->cloning)
 361                 set_helper_option(transport, "cloning", "true");
 362
 363         if (data->transport_options.update_shallow)
 364                 set_helper_option(transport, "update-shallow", "true");
 365
 366         for (i = 0; i < nr_heads; i++) {
 367                 const struct ref *posn = to_fetch[i];
 368                 if (posn->status & REF_STATUS_UPTODATE)
 369                         continue;
 370
 371                 strbuf_addf(&buf, "fetch %s %s\n",
 372                             sha1_to_hex(posn->old_sha1), posn->name);
 373         }
 374
 375         strbuf_addch(&buf, '\n');
 376         sendline(data, &buf);
 377
 378         while (1) {
 379                 if (recvline(data, &buf))
 380                         exit(128);
 381
 382                 if (starts_with(buf.buf, "lock ")) {
 383                         const char *name = buf.buf + 5;
 384                         if (transport->pack_lockfile)
 385                                 warning("%s also locked %s", data->name, name);
 386                         else
 387                                 transport->pack_lockfile = xstrdup(name);
 388                 }
 389                 else if (data->check_connectivity &&
 390                          data->transport_options.check_self_contained_and_connected &&
 391                          !strcmp(buf.buf, "connectivity-ok"))
 392                         data->transport_options.self_contained_and_connected = 1;
 393                 else if (!buf.len)
 394                         break;
 395                 else
 396                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 397         }
 398         strbuf_release(&buf);
 399         return 0;
 400 }
 401
 402 static int get_importer(struct transport *transport, struct child_process *fastimport)
 403 {
 404         struct child_process *helper = get_helper(transport);
 405         struct helper_data *data = transport->data;
 406         struct argv_array argv = ARGV_ARRAY_INIT;
 407         int cat_blob_fd, code;
 408         memset(fastimport, 0, sizeof(*fastimport));
 409         fastimport->in = helper->out;
 410         argv_array_push(&argv, "fast-import");
 411         argv_array_push(&argv, debug ? "--stats" : "--quiet");
 412
 413         if (data->bidi_import) {
 414                 cat_blob_fd = xdup(helper->in);
 415                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 416         }
 417         fastimport->argv = argv.argv;
 418         fastimport->git_cmd = 1;
 419
 420         code = start_command(fastimport);
 421         return code;
 422 }
 423
 424 static int get_exporter(struct transport *transport,
 425                         struct child_process *fastexport,
 426                         struct string_list *revlist_args)
 427 {
 428         struct helper_data *data = transport->data;
 429         struct child_process *helper = get_helper(transport);
 430         int argc = 0, i;
 431         memset(fastexport, 0, sizeof(*fastexport));
 432
 433         /* we need to duplicate helper->in because we want to use it after
 434          * fastexport is done with it. */
 435         fastexport->out = dup(helper->in);
 436         fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
 437         fastexport->argv[argc++] = "fast-export";
 438         fastexport->argv[argc++] = "--use-done-feature";
 439         fastexport->argv[argc++] = data->signed_tags ?
 440                 "--signed-tags=verbatim" : "--signed-tags=warn-strip";
 441         if (data->export_marks)
 442                 fastexport->argv[argc++] = data->export_marks;
 443         if (data->import_marks)
 444                 fastexport->argv[argc++] = data->import_marks;
 445
 446         for (i = 0; i < revlist_args->nr; i++)
 447                 fastexport->argv[argc++] = revlist_args->items[i].string;
 448
 449         fastexport->git_cmd = 1;
 450         return start_command(fastexport);
 451 }
 452
 453 static int fetch_with_import(struct transport *transport,
 454                              int nr_heads, struct ref **to_fetch)
 455 {
 456         struct child_process fastimport;
 457         struct helper_data *data = transport->data;
 458         int i;
 459         struct ref *posn;
 460         struct strbuf buf = STRBUF_INIT;
 461
 462         get_helper(transport);
 463
 464         if (get_importer(transport, &fastimport))
 465                 die("Couldn't run fast-import");
 466
 467         for (i = 0; i < nr_heads; i++) {
 468                 posn = to_fetch[i];
 469                 if (posn->status & REF_STATUS_UPTODATE)
 470                         continue;
 471
 472                 strbuf_addf(&buf, "import %s\n", posn->name);
 473                 sendline(data, &buf);
 474                 strbuf_reset(&buf);
 475         }
 476
 477         write_constant(data->helper->in, "\n");
 478         /*
 479          * remote-helpers that advertise the bidi-import capability are required to
 480          * buffer the complete batch of import commands until this newline before
 481          * sending data to fast-import.
 482          * These helpers read back data from fast-import on their stdin, which could
 483          * be mixed with import commands, otherwise.
 484          */
 485
 486         if (finish_command(&fastimport))
 487                 die("Error while running fast-import");
 488         argv_array_free_detached(fastimport.argv);
 489
 490         /*
 491          * The fast-import stream of a remote helper that advertises
 492          * the "refspec" capability writes to the refs named after the
 493          * right hand side of the first refspec matching each ref we
 494          * were fetching.
 495          *
 496          * (If no "refspec" capability was specified, for historical
 497          * reasons we default to the equivalent of *:*.)
 498          *
 499          * Store the result in to_fetch[i].old_sha1.  Callers such
 500          * as "git fetch" can use the value to write feedback to the
 501          * terminal, populate FETCH_HEAD, and determine what new value
 502          * should be written to peer_ref if the update is a
 503          * fast-forward or this is a forced update.
 504          */
 505         for (i = 0; i < nr_heads; i++) {
 506                 char *private;
 507                 posn = to_fetch[i];
 508                 if (posn->status & REF_STATUS_UPTODATE)
 509                         continue;
 510                 if (data->refspecs)
 511                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 512                 else
 513                         private = xstrdup(posn->name);
 514                 if (private) {
 515                         read_ref(private, posn->old_sha1);
 516                         free(private);
 517                 }
 518         }
 519         strbuf_release(&buf);
 520         return 0;
 521 }
 522
 523 static int process_connect_service(struct transport *transport,
 524                                    const char *name, const char *exec)
 525 {
 526         struct helper_data *data = transport->data;
 527         struct strbuf cmdbuf = STRBUF_INIT;
 528         struct child_process *helper;
 529         int r, duped, ret = 0;
 530         FILE *input;
 531
 532         helper = get_helper(transport);
 533
 534         /*
 535          * Yes, dup the pipe another time, as we need unbuffered version
 536          * of input pipe as FILE*. fclose() closes the underlying fd and
 537          * stream buffering only can be changed before first I/O operation
 538          * on it.
 539          */
 540         duped = dup(helper->out);
 541         if (duped < 0)
 542                 die_errno("Can't dup helper output fd");
 543         input = xfdopen(duped, "r");
 544         setvbuf(input, NULL, _IONBF, 0);
 545
 546         /*
 547          * Handle --upload-pack and friends. This is fire and forget...
 548          * just warn if it fails.
 549          */
 550         if (strcmp(name, exec)) {
 551                 r = set_helper_option(transport, "servpath", exec);
 552                 if (r > 0)
 553                         warning("Setting remote service path not supported by protocol.");
 554                 else if (r < 0)
 555                         warning("Invalid remote service path.");
 556         }
 557
 558         if (data->connect)
 559                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 560         else
 561                 goto exit;
 562
 563         sendline(data, &cmdbuf);
 564         if (recvline_fh(input, &cmdbuf, name))
 565                 exit(128);
 566
 567         if (!strcmp(cmdbuf.buf, "")) {
 568                 data->no_disconnect_req = 1;
 569                 if (debug)
 570                         fprintf(stderr, "Debug: Smart transport connection "
 571                                 "ready.\n");
 572                 ret = 1;
 573         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 574                 if (debug)
 575                         fprintf(stderr, "Debug: Falling back to dumb "
 576                                 "transport.\n");
 577         } else
 578                 die("Unknown response to connect: %s",
 579                         cmdbuf.buf);
 580
 581 exit:
 582         fclose(input);
 583         return ret;
 584 }
 585
 586 static int process_connect(struct transport *transport,
 587                                      int for_push)
 588 {
 589         struct helper_data *data = transport->data;
 590         const char *name;
 591         const char *exec;
 592
 593         name = for_push ? "git-receive-pack" : "git-upload-pack";
 594         if (for_push)
 595                 exec = data->transport_options.receivepack;
 596         else
 597                 exec = data->transport_options.uploadpack;
 598
 599         return process_connect_service(transport, name, exec);
 600 }
 601
 602 static int connect_helper(struct transport *transport, const char *name,
 603                    const char *exec, int fd[2])
 604 {
 605         struct helper_data *data = transport->data;
 606
 607         /* Get_helper so connect is inited. */
 608         get_helper(transport);
 609         if (!data->connect)
 610                 die("Operation not supported by protocol.");
 611
 612         if (!process_connect_service(transport, name, exec))
 613                 die("Can't connect to subservice %s.", name);
 614
 615         fd[0] = data->helper->out;
 616         fd[1] = data->helper->in;
 617         return 0;
 618 }
 619
 620 static int fetch(struct transport *transport,
 621                  int nr_heads, struct ref **to_fetch)
 622 {
 623         struct helper_data *data = transport->data;
 624         int i, count;
 625
 626         if (process_connect(transport, 0)) {
 627                 do_take_over(transport);
 628                 return transport->fetch(transport, nr_heads, to_fetch);
 629         }
 630
 631         count = 0;
 632         for (i = 0; i < nr_heads; i++)
 633                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 634                         count++;
 635
 636         if (!count)
 637                 return 0;
 638
 639         if (data->fetch)
 640                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 641
 642         if (data->import)
 643                 return fetch_with_import(transport, nr_heads, to_fetch);
 644
 645         return -1;
 646 }
 647
 648 static int push_update_ref_status(struct strbuf *buf,
 649                                    struct ref **ref,
 650                                    struct ref *remote_refs)
 651 {
 652         char *refname, *msg;
 653         int status, forced = 0;
 654
 655         if (starts_with(buf->buf, "ok ")) {
 656                 status = REF_STATUS_OK;
 657                 refname = buf->buf + 3;
 658         } else if (starts_with(buf->buf, "error ")) {
 659                 status = REF_STATUS_REMOTE_REJECT;
 660                 refname = buf->buf + 6;
 661         } else
 662                 die("expected ok/error, helper said '%s'", buf->buf);
 663
 664         msg = strchr(refname, ' ');
 665         if (msg) {
 666                 struct strbuf msg_buf = STRBUF_INIT;
 667                 const char *end;
 668
 669                 *msg++ = '\0';
 670                 if (!unquote_c_style(&msg_buf, msg, &end))
 671                         msg = strbuf_detach(&msg_buf, NULL);
 672                 else
 673                         msg = xstrdup(msg);
 674                 strbuf_release(&msg_buf);
 675
 676                 if (!strcmp(msg, "no match")) {
 677                         status = REF_STATUS_NONE;
 678                         free(msg);
 679                         msg = NULL;
 680                 }
 681                 else if (!strcmp(msg, "up to date")) {
 682                         status = REF_STATUS_UPTODATE;
 683                         free(msg);
 684                         msg = NULL;
 685                 }
 686                 else if (!strcmp(msg, "non-fast forward")) {
 687                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 688                         free(msg);
 689                         msg = NULL;
 690                 }
 691                 else if (!strcmp(msg, "already exists")) {
 692                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 693                         free(msg);
 694                         msg = NULL;
 695                 }
 696                 else if (!strcmp(msg, "fetch first")) {
 697                         status = REF_STATUS_REJECT_FETCH_FIRST;
 698                         free(msg);
 699                         msg = NULL;
 700                 }
 701                 else if (!strcmp(msg, "needs force")) {
 702                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 703                         free(msg);
 704                         msg = NULL;
 705                 }
 706                 else if (!strcmp(msg, "stale info")) {
 707                         status = REF_STATUS_REJECT_STALE;
 708                         free(msg);
 709                         msg = NULL;
 710                 }
 711                 else if (!strcmp(msg, "forced update")) {
 712                         forced = 1;
 713                         free(msg);
 714                         msg = NULL;
 715                 }
 716         }
 717
 718         if (*ref)
 719                 *ref = find_ref_by_name(*ref, refname);
 720         if (!*ref)
 721                 *ref = find_ref_by_name(remote_refs, refname);
 722         if (!*ref) {
 723                 warning("helper reported unexpected status of %s", refname);
 724                 return 1;
 725         }
 726
 727         if ((*ref)->status != REF_STATUS_NONE) {
 728                 /*
 729                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 730                  * status reported by the remote helper if the latter is 'no match'.
 731                  */
 732                 if (status == REF_STATUS_NONE)
 733                         return 1;
 734         }
 735
 736         (*ref)->status = status;
 737         (*ref)->forced_update |= forced;
 738         (*ref)->remote_status = msg;
 739         return !(status == REF_STATUS_OK);
 740 }
 741
 742 static void push_update_refs_status(struct helper_data *data,
 743                                     struct ref *remote_refs,
 744                                     int flags)
 745 {
 746         struct strbuf buf = STRBUF_INIT;
 747         struct ref *ref = remote_refs;
 748         for (;;) {
 749                 char *private;
 750
 751                 if (recvline(data, &buf))
 752                         exit(128);
 753                 if (!buf.len)
 754                         break;
 755
 756                 if (push_update_ref_status(&buf, &ref, remote_refs))
 757                         continue;
 758
 759                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 760                         continue;
 761
 762                 /* propagate back the update to the remote namespace */
 763                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 764                 if (!private)
 765                         continue;
 766                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 767                 free(private);
 768         }
 769         strbuf_release(&buf);
 770 }
 771
 772 static int push_refs_with_push(struct transport *transport,
 773                                struct ref *remote_refs, int flags)
 774 {
 775         int force_all = flags & TRANSPORT_PUSH_FORCE;
 776         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 777         struct helper_data *data = transport->data;
 778         struct strbuf buf = STRBUF_INIT;
 779         struct ref *ref;
 780         struct string_list cas_options = STRING_LIST_INIT_DUP;
 781         struct string_list_item *cas_option;
 782
 783         get_helper(transport);
 784         if (!data->push)
 785                 return 1;
 786
 787         for (ref = remote_refs; ref; ref = ref->next) {
 788                 if (!ref->peer_ref && !mirror)
 789                         continue;
 790
 791                 /* Check for statuses set by set_ref_status_for_push() */
 792                 switch (ref->status) {
 793                 case REF_STATUS_REJECT_NONFASTFORWARD:
 794                 case REF_STATUS_REJECT_STALE:
 795                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 796                 case REF_STATUS_UPTODATE:
 797                         continue;
 798                 default:
 799                         ; /* do nothing */
 800                 }
 801
 802                 if (force_all)
 803                         ref->force = 1;
 804
 805                 strbuf_addstr(&buf, "push ");
 806                 if (!ref->deletion) {
 807                         if (ref->force)
 808                                 strbuf_addch(&buf, '+');
 809                         if (ref->peer_ref)
 810                                 strbuf_addstr(&buf, ref->peer_ref->name);
 811                         else
 812                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 813                 }
 814                 strbuf_addch(&buf, ':');
 815                 strbuf_addstr(&buf, ref->name);
 816                 strbuf_addch(&buf, '\n');
 817
 818                 /*
 819                  * The "--force-with-lease" options without explicit
 820                  * values to expect have already been expanded into
 821                  * the ref->old_sha1_expect[] field; we can ignore
 822                  * transport->smart_options->cas altogether and instead
 823                  * can enumerate them from the refs.
 824                  */
 825                 if (ref->expect_old_sha1) {
 826                         struct strbuf cas = STRBUF_INIT;
 827                         strbuf_addf(&cas, "%s:%s",
 828                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 829                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 830                 }
 831         }
 832         if (buf.len == 0) {
 833                 string_list_clear(&cas_options, 0);
 834                 return 0;
 835         }
 836
 837         standard_options(transport);
 838         for_each_string_list_item(cas_option, &cas_options)
 839                 set_helper_option(transport, "cas", cas_option->string);
 840
 841         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 842                 if (set_helper_option(transport, "dry-run", "true") != 0)
 843                         die("helper %s does not support dry-run", data->name);
 844         }
 845
 846         strbuf_addch(&buf, '\n');
 847         sendline(data, &buf);
 848         strbuf_release(&buf);
 849
 850         push_update_refs_status(data, remote_refs, flags);
 851         return 0;
 852 }
 853
 854 static int push_refs_with_export(struct transport *transport,
 855                 struct ref *remote_refs, int flags)
 856 {
 857         struct ref *ref;
 858         struct child_process *helper, exporter;
 859         struct helper_data *data = transport->data;
 860         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 861         struct strbuf buf = STRBUF_INIT;
 862
 863         if (!data->refspecs)
 864                 die("remote-helper doesn't support push; refspec needed");
 865
 866         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 867                 if (set_helper_option(transport, "dry-run", "true") != 0)
 868                         die("helper %s does not support dry-run", data->name);
 869         }
 870
 871         if (flags & TRANSPORT_PUSH_FORCE) {
 872                 if (set_helper_option(transport, "force", "true") != 0)
 873                         warning("helper %s does not support 'force'", data->name);
 874         }
 875
 876         helper = get_helper(transport);
 877
 878         write_constant(helper->in, "export\n");
 879
 880         strbuf_reset(&buf);
 881
 882         for (ref = remote_refs; ref; ref = ref->next) {
 883                 char *private;
 884                 unsigned char sha1[20];
 885
 886                 if (ref->deletion)
 887                         die("remote-helpers do not support ref deletion");
 888
 889                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 890                 if (private && !get_sha1(private, sha1)) {
 891                         strbuf_addf(&buf, "^%s", private);
 892                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 893                         hashcpy(ref->old_sha1, sha1);
 894                 }
 895                 free(private);
 896
 897                 if (ref->peer_ref) {
 898                         if (strcmp(ref->peer_ref->name, ref->name))
 899                                 die("remote-helpers do not support old:new syntax");
 900                         string_list_append(&revlist_args, ref->peer_ref->name);
 901                 }
 902         }
 903
 904         if (get_exporter(transport, &exporter, &revlist_args))
 905                 die("Couldn't run fast-export");
 906
 907         if (finish_command(&exporter))
 908                 die("Error while running fast-export");
 909         push_update_refs_status(data, remote_refs, flags);
 910         return 0;
 911 }
 912
 913 static int push_refs(struct transport *transport,
 914                 struct ref *remote_refs, int flags)
 915 {
 916         struct helper_data *data = transport->data;
 917
 918         if (process_connect(transport, 1)) {
 919                 do_take_over(transport);
 920                 return transport->push_refs(transport, remote_refs, flags);
 921         }
 922
 923         if (!remote_refs) {
 924                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 925                         "Perhaps you should specify a branch such as 'master'.\n");
 926                 return 0;
 927         }
 928
 929         if (data->push)
 930                 return push_refs_with_push(transport, remote_refs, flags);
 931
 932         if (data->export)
 933                 return push_refs_with_export(transport, remote_refs, flags);
 934
 935         return -1;
 936 }
 937
 938
 939 static int has_attribute(const char *attrs, const char *attr) {
 940         int len;
 941         if (!attrs)
 942                 return 0;
 943
 944         len = strlen(attr);
 945         for (;;) {
 946                 const char *space = strchrnul(attrs, ' ');
 947                 if (len == space - attrs && !strncmp(attrs, attr, len))
 948                         return 1;
 949                 if (!*space)
 950                         return 0;
 951                 attrs = space + 1;
 952         }
 953 }
 954
 955 static struct ref *get_refs_list(struct transport *transport, int for_push)
 956 {
 957         struct helper_data *data = transport->data;
 958         struct child_process *helper;
 959         struct ref *ret = NULL;
 960         struct ref **tail = &ret;
 961         struct ref *posn;
 962         struct strbuf buf = STRBUF_INIT;
 963
 964         helper = get_helper(transport);
 965
 966         if (process_connect(transport, for_push)) {
 967                 do_take_over(transport);
 968                 return transport->get_refs_list(transport, for_push);
 969         }
 970
 971         if (data->push && for_push)
 972                 write_str_in_full(helper->in, "list for-push\n");
 973         else
 974                 write_str_in_full(helper->in, "list\n");
 975
 976         while (1) {
 977                 char *eov, *eon;
 978                 if (recvline(data, &buf))
 979                         exit(128);
 980
 981                 if (!*buf.buf)
 982                         break;
 983
 984                 eov = strchr(buf.buf, ' ');
 985                 if (!eov)
 986                         die("Malformed response in ref list: %s", buf.buf);
 987                 eon = strchr(eov + 1, ' ');
 988                 *eov = '\0';
 989                 if (eon)
 990                         *eon = '\0';
 991                 *tail = alloc_ref(eov + 1);
 992                 if (buf.buf[0] == '@')
 993                         (*tail)->symref = xstrdup(buf.buf + 1);
 994                 else if (buf.buf[0] != '?')
 995                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
 996                 if (eon) {
 997                         if (has_attribute(eon + 1, "unchanged")) {
 998                                 (*tail)->status |= REF_STATUS_UPTODATE;
 999                                 read_ref((*tail)->name, (*tail)->old_sha1);
1000                         }
1001                 }
1002                 tail = &((*tail)->next);
1003         }
1004         if (debug)
1005                 fprintf(stderr, "Debug: Read ref listing.\n");
1006         strbuf_release(&buf);
1007
1008         for (posn = ret; posn; posn = posn->next)
1009                 resolve_remote_symref(posn, ret);
1010
1011         return ret;
1012 }
1013
1014 int transport_helper_init(struct transport *transport, const char *name)
1015 {
1016         struct helper_data *data = xcalloc(sizeof(*data), 1);
1017         data->name = name;
1018
1019         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1020                 debug = 1;
1021
1022         transport->data = data;
1023         transport->set_option = set_helper_option;
1024         transport->get_refs_list = get_refs_list;
1025         transport->fetch = fetch;
1026         transport->push_refs = push_refs;
1027         transport->disconnect = release_helper;
1028         transport->connect = connect_helper;
1029         transport->smart_options = &(data->transport_options);
1030         return 0;
1031 }
1032
1033 /*
1034  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1035  * buffer less), so attempt reads and writes with up to that size.
1036  */
1037 #define BUFFERSIZE 65536
1038 /* This should be enough to hold debugging message. */
1039 #define PBUFFERSIZE 8192
1040
1041 /* Print bidirectional transfer loop debug message. */
1042 __attribute__((format (printf, 1, 2)))
1043 static void transfer_debug(const char *fmt, ...)
1044 {
1045         va_list args;
1046         char msgbuf[PBUFFERSIZE];
1047         static int debug_enabled = -1;
1048
1049         if (debug_enabled < 0)
1050                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1051         if (!debug_enabled)
1052                 return;
1053
1054         va_start(args, fmt);
1055         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1056         va_end(args);
1057         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1058 }
1059
1060 /* Stream state: More data may be coming in this direction. */
1061 #define SSTATE_TRANSFERING 0
1062 /*
1063  * Stream state: No more data coming in this direction, flushing rest of
1064  * data.
1065  */
1066 #define SSTATE_FLUSHING 1
1067 /* Stream state: Transfer in this direction finished. */
1068 #define SSTATE_FINISHED 2
1069
1070 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1071 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1072 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1073
1074 /* Unidirectional transfer. */
1075 struct unidirectional_transfer {
1076         /* Source */
1077         int src;
1078         /* Destination */
1079         int dest;
1080         /* Is source socket? */
1081         int src_is_sock;
1082         /* Is destination socket? */
1083         int dest_is_sock;
1084         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1085         int state;
1086         /* Buffer. */
1087         char buf[BUFFERSIZE];
1088         /* Buffer used. */
1089         size_t bufuse;
1090         /* Name of source. */
1091         const char *src_name;
1092         /* Name of destination. */
1093         const char *dest_name;
1094 };
1095
1096 /* Closes the target (for writing) if transfer has finished. */
1097 static void udt_close_if_finished(struct unidirectional_transfer *t)
1098 {
1099         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1100                 t->state = SSTATE_FINISHED;
1101                 if (t->dest_is_sock)
1102                         shutdown(t->dest, SHUT_WR);
1103                 else
1104                         close(t->dest);
1105                 transfer_debug("Closed %s.", t->dest_name);
1106         }
1107 }
1108
1109 /*
1110  * Tries to read read data from source into buffer. If buffer is full,
1111  * no data is read. Returns 0 on success, -1 on error.
1112  */
1113 static int udt_do_read(struct unidirectional_transfer *t)
1114 {
1115         ssize_t bytes;
1116
1117         if (t->bufuse == BUFFERSIZE)
1118                 return 0;       /* No space for more. */
1119
1120         transfer_debug("%s is readable", t->src_name);
1121         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1122         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1123                 errno != EINTR) {
1124                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1125                 return -1;
1126         } else if (bytes == 0) {
1127                 transfer_debug("%s EOF (with %i bytes in buffer)",
1128                         t->src_name, (int)t->bufuse);
1129                 t->state = SSTATE_FLUSHING;
1130         } else if (bytes > 0) {
1131                 t->bufuse += bytes;
1132                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1133                         (int)bytes, t->src_name, (int)t->bufuse);
1134         }
1135         return 0;
1136 }
1137
1138 /* Tries to write data from buffer into destination. If buffer is empty,
1139  * no data is written. Returns 0 on success, -1 on error.
1140  */
1141 static int udt_do_write(struct unidirectional_transfer *t)
1142 {
1143         ssize_t bytes;
1144
1145         if (t->bufuse == 0)
1146                 return 0;       /* Nothing to write. */
1147
1148         transfer_debug("%s is writable", t->dest_name);
1149         bytes = xwrite(t->dest, t->buf, t->bufuse);
1150         if (bytes < 0 && errno != EWOULDBLOCK) {
1151                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1152                 return -1;
1153         } else if (bytes > 0) {
1154                 t->bufuse -= bytes;
1155                 if (t->bufuse)
1156                         memmove(t->buf, t->buf + bytes, t->bufuse);
1157                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1158                         (int)bytes, t->dest_name, (int)t->bufuse);
1159         }
1160         return 0;
1161 }
1162
1163
1164 /* State of bidirectional transfer loop. */
1165 struct bidirectional_transfer_state {
1166         /* Direction from program to git. */
1167         struct unidirectional_transfer ptg;
1168         /* Direction from git to program. */
1169         struct unidirectional_transfer gtp;
1170 };
1171
1172 static void *udt_copy_task_routine(void *udt)
1173 {
1174         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1175         while (t->state != SSTATE_FINISHED) {
1176                 if (STATE_NEEDS_READING(t->state))
1177                         if (udt_do_read(t))
1178                                 return NULL;
1179                 if (STATE_NEEDS_WRITING(t->state))
1180                         if (udt_do_write(t))
1181                                 return NULL;
1182                 if (STATE_NEEDS_CLOSING(t->state))
1183                         udt_close_if_finished(t);
1184         }
1185         return udt;     /* Just some non-NULL value. */
1186 }
1187
1188 #ifndef NO_PTHREADS
1189
1190 /*
1191  * Join thread, with appropriate errors on failure. Name is name for the
1192  * thread (for error messages). Returns 0 on success, 1 on failure.
1193  */
1194 static int tloop_join(pthread_t thread, const char *name)
1195 {
1196         int err;
1197         void *tret;
1198         err = pthread_join(thread, &tret);
1199         if (!tret) {
1200                 error("%s thread failed", name);
1201                 return 1;
1202         }
1203         if (err) {
1204                 error("%s thread failed to join: %s", name, strerror(err));
1205                 return 1;
1206         }
1207         return 0;
1208 }
1209
1210 /*
1211  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1212  * -1 on failure.
1213  */
1214 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1215 {
1216         pthread_t gtp_thread;
1217         pthread_t ptg_thread;
1218         int err;
1219         int ret = 0;
1220         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1221                 &s->gtp);
1222         if (err)
1223                 die("Can't start thread for copying data: %s", strerror(err));
1224         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1225                 &s->ptg);
1226         if (err)
1227                 die("Can't start thread for copying data: %s", strerror(err));
1228
1229         ret |= tloop_join(gtp_thread, "Git to program copy");
1230         ret |= tloop_join(ptg_thread, "Program to git copy");
1231         return ret;
1232 }
1233 #else
1234
1235 /* Close the source and target (for writing) for transfer. */
1236 static void udt_kill_transfer(struct unidirectional_transfer *t)
1237 {
1238         t->state = SSTATE_FINISHED;
1239         /*
1240          * Socket read end left open isn't a disaster if nobody
1241          * attempts to read from it (mingw compat headers do not
1242          * have SHUT_RD)...
1243          *
1244          * We can't fully close the socket since otherwise gtp
1245          * task would first close the socket it sends data to
1246          * while closing the ptg file descriptors.
1247          */
1248         if (!t->src_is_sock)
1249                 close(t->src);
1250         if (t->dest_is_sock)
1251                 shutdown(t->dest, SHUT_WR);
1252         else
1253                 close(t->dest);
1254 }
1255
1256 /*
1257  * Join process, with appropriate errors on failure. Name is name for the
1258  * process (for error messages). Returns 0 on success, 1 on failure.
1259  */
1260 static int tloop_join(pid_t pid, const char *name)
1261 {
1262         int tret;
1263         if (waitpid(pid, &tret, 0) < 0) {
1264                 error("%s process failed to wait: %s", name, strerror(errno));
1265                 return 1;
1266         }
1267         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1268                 error("%s process failed", name);
1269                 return 1;
1270         }
1271         return 0;
1272 }
1273
1274 /*
1275  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1276  * -1 on failure.
1277  */
1278 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1279 {
1280         pid_t pid1, pid2;
1281         int ret = 0;
1282
1283         /* Fork thread #1: git to program. */
1284         pid1 = fork();
1285         if (pid1 < 0)
1286                 die_errno("Can't start thread for copying data");
1287         else if (pid1 == 0) {
1288                 udt_kill_transfer(&s->ptg);
1289                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1290         }
1291
1292         /* Fork thread #2: program to git. */
1293         pid2 = fork();
1294         if (pid2 < 0)
1295                 die_errno("Can't start thread for copying data");
1296         else if (pid2 == 0) {
1297                 udt_kill_transfer(&s->gtp);
1298                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1299         }
1300
1301         /*
1302          * Close both streams in parent as to not interfere with
1303          * end of file detection and wait for both tasks to finish.
1304          */
1305         udt_kill_transfer(&s->gtp);
1306         udt_kill_transfer(&s->ptg);
1307         ret |= tloop_join(pid1, "Git to program copy");
1308         ret |= tloop_join(pid2, "Program to git copy");
1309         return ret;
1310 }
1311 #endif
1312
1313 /*
1314  * Copies data from stdin to output and from input to stdout simultaneously.
1315  * Additionally filtering through given filter. If filter is NULL, uses
1316  * identity filter.
1317  */
1318 int bidirectional_transfer_loop(int input, int output)
1319 {
1320         struct bidirectional_transfer_state state;
1321
1322         /* Fill the state fields. */
1323         state.ptg.src = input;
1324         state.ptg.dest = 1;
1325         state.ptg.src_is_sock = (input == output);
1326         state.ptg.dest_is_sock = 0;
1327         state.ptg.state = SSTATE_TRANSFERING;
1328         state.ptg.bufuse = 0;
1329         state.ptg.src_name = "remote input";
1330         state.ptg.dest_name = "stdout";
1331
1332         state.gtp.src = 0;
1333         state.gtp.dest = output;
1334         state.gtp.src_is_sock = 0;
1335         state.gtp.dest_is_sock = (input == output);
1336         state.gtp.state = SSTATE_TRANSFERING;
1337         state.gtp.bufuse = 0;
1338         state.gtp.src_name = "stdin";
1339         state.gtp.dest_name = "remote output";
1340
1341         return tloop_spawnwait_tasks(&state);
1342 }