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 strbuf buf = STRBUF_INIT;
 105         struct child_process *helper;
 106         const char **refspecs = NULL;
 107         int refspec_nr = 0;
 108         int refspec_alloc = 0;
 109         int duped;
 110         int code;
 111         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 112         const char *helper_env[] = {
 113                 git_dir_buf,
 114                 NULL
 115         };
 116
 117
 118         if (data->helper)
 119                 return data->helper;
 120
 121         helper = xcalloc(1, sizeof(*helper));
 122         helper->in = -1;
 123         helper->out = -1;
 124         helper->err = 0;
 125         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 126         argv_array_push(&helper->args, transport->remote->name);
 127         argv_array_push(&helper->args, remove_ext_force(transport->url));
 128         helper->git_cmd = 0;
 129         helper->silent_exec_failure = 1;
 130
 131         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 132         helper->env = helper_env;
 133
 134         code = start_command(helper);
 135         if (code < 0 && errno == ENOENT)
 136                 die("Unable to find remote helper for '%s'", data->name);
 137         else if (code != 0)
 138                 exit(code);
 139
 140         data->helper = helper;
 141         data->no_disconnect_req = 0;
 142
 143         /*
 144          * Open the output as FILE* so strbuf_getline() can be used.
 145          * Do this with duped fd because fclose() will close the fd,
 146          * and stuff like taking over will require the fd to remain.
 147          */
 148         duped = dup(helper->out);
 149         if (duped < 0)
 150                 die_errno("Can't dup helper output fd");
 151         data->out = xfdopen(duped, "r");
 152
 153         write_constant(helper->in, "capabilities\n");
 154
 155         while (1) {
 156                 const char *capname, *arg;
 157                 int mandatory = 0;
 158                 if (recvline(data, &buf))
 159                         exit(128);
 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, "bidi-import"))
 181                         data->bidi_import = 1;
 182                 else if (!strcmp(capname, "export"))
 183                         data->export = 1;
 184                 else if (!strcmp(capname, "check-connectivity"))
 185                         data->check_connectivity = 1;
 186                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 187                         ALLOC_GROW(refspecs,
 188                                    refspec_nr + 1,
 189                                    refspec_alloc);
 190                         refspecs[refspec_nr++] = xstrdup(arg);
 191                 } else if (!strcmp(capname, "connect")) {
 192                         data->connect = 1;
 193                 } else if (!strcmp(capname, "signed-tags")) {
 194                         data->signed_tags = 1;
 195                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 196                         data->export_marks = xstrdup(arg);
 197                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 198                         data->import_marks = xstrdup(arg);
 199                 } else if (starts_with(capname, "no-private-update")) {
 200                         data->no_private_update = 1;
 201                 } else if (mandatory) {
 202                         die("Unknown mandatory capability %s. This remote "
 203                             "helper probably needs newer version of Git.",
 204                             capname);
 205                 }
 206         }
 207         if (refspecs) {
 208                 int i;
 209                 data->refspec_nr = refspec_nr;
 210                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 211                 for (i = 0; i < refspec_nr; i++)
 212                         free((char *)refspecs[i]);
 213                 free(refspecs);
 214         } else if (data->import || data->bidi_import || data->export) {
 215                 warning("This remote helper should implement refspec capability.");
 216         }
 217         strbuf_release(&buf);
 218         if (debug)
 219                 fprintf(stderr, "Debug: Capabilities complete.\n");
 220         return data->helper;
 221 }
 222
 223 static int disconnect_helper(struct transport *transport)
 224 {
 225         struct helper_data *data = transport->data;
 226         int res = 0;
 227
 228         if (data->helper) {
 229                 if (debug)
 230                         fprintf(stderr, "Debug: Disconnecting.\n");
 231                 if (!data->no_disconnect_req) {
 232                         /*
 233                          * Ignore write errors; there's nothing we can do,
 234                          * since we're about to close the pipe anyway. And the
 235                          * most likely error is EPIPE due to the helper dying
 236                          * to report an error itself.
 237                          */
 238                         sigchain_push(SIGPIPE, SIG_IGN);
 239                         xwrite(data->helper->in, "\n", 1);
 240                         sigchain_pop(SIGPIPE);
 241                 }
 242                 close(data->helper->in);
 243                 close(data->helper->out);
 244                 fclose(data->out);
 245                 res = finish_command(data->helper);
 246                 free(data->helper);
 247                 data->helper = NULL;
 248         }
 249         return res;
 250 }
 251
 252 static const char *unsupported_options[] = {
 253         TRANS_OPT_UPLOADPACK,
 254         TRANS_OPT_RECEIVEPACK,
 255         TRANS_OPT_THIN,
 256         TRANS_OPT_KEEP
 257         };
 258
 259 static const char *boolean_options[] = {
 260         TRANS_OPT_THIN,
 261         TRANS_OPT_KEEP,
 262         TRANS_OPT_FOLLOWTAGS
 263         };
 264
 265 static int set_helper_option(struct transport *transport,
 266                           const char *name, const char *value)
 267 {
 268         struct helper_data *data = transport->data;
 269         struct strbuf buf = STRBUF_INIT;
 270         int i, ret, is_bool = 0;
 271
 272         get_helper(transport);
 273
 274         if (!data->option)
 275                 return 1;
 276
 277         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 278                 if (!strcmp(name, unsupported_options[i]))
 279                         return 1;
 280         }
 281
 282         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 283                 if (!strcmp(name, boolean_options[i])) {
 284                         is_bool = 1;
 285                         break;
 286                 }
 287         }
 288
 289         strbuf_addf(&buf, "option %s ", name);
 290         if (is_bool)
 291                 strbuf_addstr(&buf, value ? "true" : "false");
 292         else
 293                 quote_c_style(value, &buf, NULL, 0);
 294         strbuf_addch(&buf, '\n');
 295
 296         sendline(data, &buf);
 297         if (recvline(data, &buf))
 298                 exit(128);
 299
 300         if (!strcmp(buf.buf, "ok"))
 301                 ret = 0;
 302         else if (starts_with(buf.buf, "error")) {
 303                 ret = -1;
 304         } else if (!strcmp(buf.buf, "unsupported"))
 305                 ret = 1;
 306         else {
 307                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 308                 ret = 1;
 309         }
 310         strbuf_release(&buf);
 311         return ret;
 312 }
 313
 314 static void standard_options(struct transport *t)
 315 {
 316         char buf[16];
 317         int n;
 318         int v = t->verbose;
 319
 320         set_helper_option(t, "progress", t->progress ? "true" : "false");
 321
 322         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 323         if (n >= sizeof(buf))
 324                 die("impossibly large verbosity value");
 325         set_helper_option(t, "verbosity", buf);
 326 }
 327
 328 static int release_helper(struct transport *transport)
 329 {
 330         int res = 0;
 331         struct helper_data *data = transport->data;
 332         free_refspec(data->refspec_nr, data->refspecs);
 333         data->refspecs = NULL;
 334         res = disconnect_helper(transport);
 335         free(transport->data);
 336         return res;
 337 }
 338
 339 static int fetch_with_fetch(struct transport *transport,
 340                             int nr_heads, struct ref **to_fetch)
 341 {
 342         struct helper_data *data = transport->data;
 343         int i;
 344         struct strbuf buf = STRBUF_INIT;
 345
 346         standard_options(transport);
 347         if (data->check_connectivity &&
 348             data->transport_options.check_self_contained_and_connected)
 349                 set_helper_option(transport, "check-connectivity", "true");
 350
 351         if (transport->cloning)
 352                 set_helper_option(transport, "cloning", "true");
 353
 354         if (data->transport_options.update_shallow)
 355                 set_helper_option(transport, "update-shallow", "true");
 356
 357         for (i = 0; i < nr_heads; i++) {
 358                 const struct ref *posn = to_fetch[i];
 359                 if (posn->status & REF_STATUS_UPTODATE)
 360                         continue;
 361
 362                 strbuf_addf(&buf, "fetch %s %s\n",
 363                             sha1_to_hex(posn->old_sha1), posn->name);
 364         }
 365
 366         strbuf_addch(&buf, '\n');
 367         sendline(data, &buf);
 368
 369         while (1) {
 370                 if (recvline(data, &buf))
 371                         exit(128);
 372
 373                 if (starts_with(buf.buf, "lock ")) {
 374                         const char *name = buf.buf + 5;
 375                         if (transport->pack_lockfile)
 376                                 warning("%s also locked %s", data->name, name);
 377                         else
 378                                 transport->pack_lockfile = xstrdup(name);
 379                 }
 380                 else if (data->check_connectivity &&
 381                          data->transport_options.check_self_contained_and_connected &&
 382                          !strcmp(buf.buf, "connectivity-ok"))
 383                         data->transport_options.self_contained_and_connected = 1;
 384                 else if (!buf.len)
 385                         break;
 386                 else
 387                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 388         }
 389         strbuf_release(&buf);
 390         return 0;
 391 }
 392
 393 static int get_importer(struct transport *transport, struct child_process *fastimport)
 394 {
 395         struct child_process *helper = get_helper(transport);
 396         struct helper_data *data = transport->data;
 397         int cat_blob_fd, code;
 398         memset(fastimport, 0, sizeof(*fastimport));
 399         fastimport->in = helper->out;
 400         argv_array_push(&fastimport->args, "fast-import");
 401         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 402
 403         if (data->bidi_import) {
 404                 cat_blob_fd = xdup(helper->in);
 405                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 406         }
 407         fastimport->git_cmd = 1;
 408
 409         code = start_command(fastimport);
 410         return code;
 411 }
 412
 413 static int get_exporter(struct transport *transport,
 414                         struct child_process *fastexport,
 415                         struct string_list *revlist_args)
 416 {
 417         struct helper_data *data = transport->data;
 418         struct child_process *helper = get_helper(transport);
 419         int i;
 420
 421         memset(fastexport, 0, sizeof(*fastexport));
 422
 423         /* we need to duplicate helper->in because we want to use it after
 424          * fastexport is done with it. */
 425         fastexport->out = dup(helper->in);
 426         argv_array_push(&fastexport->args, "fast-export");
 427         argv_array_push(&fastexport->args, "--use-done-feature");
 428         argv_array_push(&fastexport->args, data->signed_tags ?
 429                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 430         if (data->export_marks)
 431                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 432         if (data->import_marks)
 433                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 434
 435         for (i = 0; i < revlist_args->nr; i++)
 436                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 437
 438         fastexport->git_cmd = 1;
 439         return start_command(fastexport);
 440 }
 441
 442 static int fetch_with_import(struct transport *transport,
 443                              int nr_heads, struct ref **to_fetch)
 444 {
 445         struct child_process fastimport;
 446         struct helper_data *data = transport->data;
 447         int i;
 448         struct ref *posn;
 449         struct strbuf buf = STRBUF_INIT;
 450
 451         get_helper(transport);
 452
 453         if (get_importer(transport, &fastimport))
 454                 die("Couldn't run fast-import");
 455
 456         for (i = 0; i < nr_heads; i++) {
 457                 posn = to_fetch[i];
 458                 if (posn->status & REF_STATUS_UPTODATE)
 459                         continue;
 460
 461                 strbuf_addf(&buf, "import %s\n", posn->name);
 462                 sendline(data, &buf);
 463                 strbuf_reset(&buf);
 464         }
 465
 466         write_constant(data->helper->in, "\n");
 467         /*
 468          * remote-helpers that advertise the bidi-import capability are required to
 469          * buffer the complete batch of import commands until this newline before
 470          * sending data to fast-import.
 471          * These helpers read back data from fast-import on their stdin, which could
 472          * be mixed with import commands, otherwise.
 473          */
 474
 475         if (finish_command(&fastimport))
 476                 die("Error while running fast-import");
 477
 478         /*
 479          * The fast-import stream of a remote helper that advertises
 480          * the "refspec" capability writes to the refs named after the
 481          * right hand side of the first refspec matching each ref we
 482          * were fetching.
 483          *
 484          * (If no "refspec" capability was specified, for historical
 485          * reasons we default to the equivalent of *:*.)
 486          *
 487          * Store the result in to_fetch[i].old_sha1.  Callers such
 488          * as "git fetch" can use the value to write feedback to the
 489          * terminal, populate FETCH_HEAD, and determine what new value
 490          * should be written to peer_ref if the update is a
 491          * fast-forward or this is a forced update.
 492          */
 493         for (i = 0; i < nr_heads; i++) {
 494                 char *private;
 495                 posn = to_fetch[i];
 496                 if (posn->status & REF_STATUS_UPTODATE)
 497                         continue;
 498                 if (data->refspecs)
 499                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 500                 else
 501                         private = xstrdup(posn->name);
 502                 if (private) {
 503                         read_ref(private, posn->old_sha1);
 504                         free(private);
 505                 }
 506         }
 507         strbuf_release(&buf);
 508         return 0;
 509 }
 510
 511 static int process_connect_service(struct transport *transport,
 512                                    const char *name, const char *exec)
 513 {
 514         struct helper_data *data = transport->data;
 515         struct strbuf cmdbuf = STRBUF_INIT;
 516         struct child_process *helper;
 517         int r, duped, ret = 0;
 518         FILE *input;
 519
 520         helper = get_helper(transport);
 521
 522         /*
 523          * Yes, dup the pipe another time, as we need unbuffered version
 524          * of input pipe as FILE*. fclose() closes the underlying fd and
 525          * stream buffering only can be changed before first I/O operation
 526          * on it.
 527          */
 528         duped = dup(helper->out);
 529         if (duped < 0)
 530                 die_errno("Can't dup helper output fd");
 531         input = xfdopen(duped, "r");
 532         setvbuf(input, NULL, _IONBF, 0);
 533
 534         /*
 535          * Handle --upload-pack and friends. This is fire and forget...
 536          * just warn if it fails.
 537          */
 538         if (strcmp(name, exec)) {
 539                 r = set_helper_option(transport, "servpath", exec);
 540                 if (r > 0)
 541                         warning("Setting remote service path not supported by protocol.");
 542                 else if (r < 0)
 543                         warning("Invalid remote service path.");
 544         }
 545
 546         if (data->connect)
 547                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 548         else
 549                 goto exit;
 550
 551         sendline(data, &cmdbuf);
 552         if (recvline_fh(input, &cmdbuf, name))
 553                 exit(128);
 554
 555         if (!strcmp(cmdbuf.buf, "")) {
 556                 data->no_disconnect_req = 1;
 557                 if (debug)
 558                         fprintf(stderr, "Debug: Smart transport connection "
 559                                 "ready.\n");
 560                 ret = 1;
 561         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 562                 if (debug)
 563                         fprintf(stderr, "Debug: Falling back to dumb "
 564                                 "transport.\n");
 565         } else
 566                 die("Unknown response to connect: %s",
 567                         cmdbuf.buf);
 568
 569 exit:
 570         fclose(input);
 571         return ret;
 572 }
 573
 574 static int process_connect(struct transport *transport,
 575                                      int for_push)
 576 {
 577         struct helper_data *data = transport->data;
 578         const char *name;
 579         const char *exec;
 580
 581         name = for_push ? "git-receive-pack" : "git-upload-pack";
 582         if (for_push)
 583                 exec = data->transport_options.receivepack;
 584         else
 585                 exec = data->transport_options.uploadpack;
 586
 587         return process_connect_service(transport, name, exec);
 588 }
 589
 590 static int connect_helper(struct transport *transport, const char *name,
 591                    const char *exec, int fd[2])
 592 {
 593         struct helper_data *data = transport->data;
 594
 595         /* Get_helper so connect is inited. */
 596         get_helper(transport);
 597         if (!data->connect)
 598                 die("Operation not supported by protocol.");
 599
 600         if (!process_connect_service(transport, name, exec))
 601                 die("Can't connect to subservice %s.", name);
 602
 603         fd[0] = data->helper->out;
 604         fd[1] = data->helper->in;
 605         return 0;
 606 }
 607
 608 static int fetch(struct transport *transport,
 609                  int nr_heads, struct ref **to_fetch)
 610 {
 611         struct helper_data *data = transport->data;
 612         int i, count;
 613
 614         if (process_connect(transport, 0)) {
 615                 do_take_over(transport);
 616                 return transport->fetch(transport, nr_heads, to_fetch);
 617         }
 618
 619         count = 0;
 620         for (i = 0; i < nr_heads; i++)
 621                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 622                         count++;
 623
 624         if (!count)
 625                 return 0;
 626
 627         if (data->fetch)
 628                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 629
 630         if (data->import)
 631                 return fetch_with_import(transport, nr_heads, to_fetch);
 632
 633         return -1;
 634 }
 635
 636 static int push_update_ref_status(struct strbuf *buf,
 637                                    struct ref **ref,
 638                                    struct ref *remote_refs)
 639 {
 640         char *refname, *msg;
 641         int status, forced = 0;
 642
 643         if (starts_with(buf->buf, "ok ")) {
 644                 status = REF_STATUS_OK;
 645                 refname = buf->buf + 3;
 646         } else if (starts_with(buf->buf, "error ")) {
 647                 status = REF_STATUS_REMOTE_REJECT;
 648                 refname = buf->buf + 6;
 649         } else
 650                 die("expected ok/error, helper said '%s'", buf->buf);
 651
 652         msg = strchr(refname, ' ');
 653         if (msg) {
 654                 struct strbuf msg_buf = STRBUF_INIT;
 655                 const char *end;
 656
 657                 *msg++ = '\0';
 658                 if (!unquote_c_style(&msg_buf, msg, &end))
 659                         msg = strbuf_detach(&msg_buf, NULL);
 660                 else
 661                         msg = xstrdup(msg);
 662                 strbuf_release(&msg_buf);
 663
 664                 if (!strcmp(msg, "no match")) {
 665                         status = REF_STATUS_NONE;
 666                         free(msg);
 667                         msg = NULL;
 668                 }
 669                 else if (!strcmp(msg, "up to date")) {
 670                         status = REF_STATUS_UPTODATE;
 671                         free(msg);
 672                         msg = NULL;
 673                 }
 674                 else if (!strcmp(msg, "non-fast forward")) {
 675                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 676                         free(msg);
 677                         msg = NULL;
 678                 }
 679                 else if (!strcmp(msg, "already exists")) {
 680                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 681                         free(msg);
 682                         msg = NULL;
 683                 }
 684                 else if (!strcmp(msg, "fetch first")) {
 685                         status = REF_STATUS_REJECT_FETCH_FIRST;
 686                         free(msg);
 687                         msg = NULL;
 688                 }
 689                 else if (!strcmp(msg, "needs force")) {
 690                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 691                         free(msg);
 692                         msg = NULL;
 693                 }
 694                 else if (!strcmp(msg, "stale info")) {
 695                         status = REF_STATUS_REJECT_STALE;
 696                         free(msg);
 697                         msg = NULL;
 698                 }
 699                 else if (!strcmp(msg, "forced update")) {
 700                         forced = 1;
 701                         free(msg);
 702                         msg = NULL;
 703                 }
 704         }
 705
 706         if (*ref)
 707                 *ref = find_ref_by_name(*ref, refname);
 708         if (!*ref)
 709                 *ref = find_ref_by_name(remote_refs, refname);
 710         if (!*ref) {
 711                 warning("helper reported unexpected status of %s", refname);
 712                 return 1;
 713         }
 714
 715         if ((*ref)->status != REF_STATUS_NONE) {
 716                 /*
 717                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 718                  * status reported by the remote helper if the latter is 'no match'.
 719                  */
 720                 if (status == REF_STATUS_NONE)
 721                         return 1;
 722         }
 723
 724         (*ref)->status = status;
 725         (*ref)->forced_update |= forced;
 726         (*ref)->remote_status = msg;
 727         return !(status == REF_STATUS_OK);
 728 }
 729
 730 static int push_update_refs_status(struct helper_data *data,
 731                                     struct ref *remote_refs,
 732                                     int flags)
 733 {
 734         struct strbuf buf = STRBUF_INIT;
 735         struct ref *ref = remote_refs;
 736         int ret = 0;
 737
 738         for (;;) {
 739                 char *private;
 740
 741                 if (recvline(data, &buf)) {
 742                         ret = 1;
 743                         break;
 744                 }
 745
 746                 if (!buf.len)
 747                         break;
 748
 749                 if (push_update_ref_status(&buf, &ref, remote_refs))
 750                         continue;
 751
 752                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 753                         continue;
 754
 755                 /* propagate back the update to the remote namespace */
 756                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 757                 if (!private)
 758                         continue;
 759                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 760                 free(private);
 761         }
 762         strbuf_release(&buf);
 763         return ret;
 764 }
 765
 766 static int push_refs_with_push(struct transport *transport,
 767                                struct ref *remote_refs, int flags)
 768 {
 769         int force_all = flags & TRANSPORT_PUSH_FORCE;
 770         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 771         struct helper_data *data = transport->data;
 772         struct strbuf buf = STRBUF_INIT;
 773         struct ref *ref;
 774         struct string_list cas_options = STRING_LIST_INIT_DUP;
 775         struct string_list_item *cas_option;
 776
 777         get_helper(transport);
 778         if (!data->push)
 779                 return 1;
 780
 781         for (ref = remote_refs; ref; ref = ref->next) {
 782                 if (!ref->peer_ref && !mirror)
 783                         continue;
 784
 785                 /* Check for statuses set by set_ref_status_for_push() */
 786                 switch (ref->status) {
 787                 case REF_STATUS_REJECT_NONFASTFORWARD:
 788                 case REF_STATUS_REJECT_STALE:
 789                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 790                 case REF_STATUS_UPTODATE:
 791                         continue;
 792                 default:
 793                         ; /* do nothing */
 794                 }
 795
 796                 if (force_all)
 797                         ref->force = 1;
 798
 799                 strbuf_addstr(&buf, "push ");
 800                 if (!ref->deletion) {
 801                         if (ref->force)
 802                                 strbuf_addch(&buf, '+');
 803                         if (ref->peer_ref)
 804                                 strbuf_addstr(&buf, ref->peer_ref->name);
 805                         else
 806                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 807                 }
 808                 strbuf_addch(&buf, ':');
 809                 strbuf_addstr(&buf, ref->name);
 810                 strbuf_addch(&buf, '\n');
 811
 812                 /*
 813                  * The "--force-with-lease" options without explicit
 814                  * values to expect have already been expanded into
 815                  * the ref->old_sha1_expect[] field; we can ignore
 816                  * transport->smart_options->cas altogether and instead
 817                  * can enumerate them from the refs.
 818                  */
 819                 if (ref->expect_old_sha1) {
 820                         struct strbuf cas = STRBUF_INIT;
 821                         strbuf_addf(&cas, "%s:%s",
 822                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 823                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 824                 }
 825         }
 826         if (buf.len == 0) {
 827                 string_list_clear(&cas_options, 0);
 828                 return 0;
 829         }
 830
 831         standard_options(transport);
 832         for_each_string_list_item(cas_option, &cas_options)
 833                 set_helper_option(transport, "cas", cas_option->string);
 834
 835         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 836                 if (set_helper_option(transport, "dry-run", "true") != 0)
 837                         die("helper %s does not support dry-run", data->name);
 838         }
 839
 840         strbuf_addch(&buf, '\n');
 841         sendline(data, &buf);
 842         strbuf_release(&buf);
 843
 844         return push_update_refs_status(data, remote_refs, flags);
 845 }
 846
 847 static int push_refs_with_export(struct transport *transport,
 848                 struct ref *remote_refs, int flags)
 849 {
 850         struct ref *ref;
 851         struct child_process *helper, exporter;
 852         struct helper_data *data = transport->data;
 853         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 854         struct strbuf buf = STRBUF_INIT;
 855
 856         if (!data->refspecs)
 857                 die("remote-helper doesn't support push; refspec needed");
 858
 859         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 860                 if (set_helper_option(transport, "dry-run", "true") != 0)
 861                         die("helper %s does not support dry-run", data->name);
 862         }
 863
 864         if (flags & TRANSPORT_PUSH_FORCE) {
 865                 if (set_helper_option(transport, "force", "true") != 0)
 866                         warning("helper %s does not support 'force'", data->name);
 867         }
 868
 869         helper = get_helper(transport);
 870
 871         write_constant(helper->in, "export\n");
 872
 873         for (ref = remote_refs; ref; ref = ref->next) {
 874                 char *private;
 875                 unsigned char sha1[20];
 876
 877                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 878                 if (private && !get_sha1(private, sha1)) {
 879                         strbuf_addf(&buf, "^%s", private);
 880                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 881                         hashcpy(ref->old_sha1, sha1);
 882                 }
 883                 free(private);
 884
 885                 if (ref->peer_ref) {
 886                         if (strcmp(ref->name, ref->peer_ref->name)) {
 887                                 if (!ref->deletion) {
 888                                         const char *name;
 889                                         int flag;
 890
 891                                         /* Follow symbolic refs (mainly for HEAD). */
 892                                         name = resolve_ref_unsafe(ref->peer_ref->name, sha1, 1, &flag);
 893                                         if (!name || !(flag & REF_ISSYMREF))
 894                                                 name = ref->peer_ref->name;
 895
 896                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 897                                 } else
 898                                         strbuf_addf(&buf, ":%s", ref->name);
 899
 900                                 string_list_append(&revlist_args, "--refspec");
 901                                 string_list_append(&revlist_args, buf.buf);
 902                                 strbuf_release(&buf);
 903                         }
 904                         if (!ref->deletion)
 905                                 string_list_append(&revlist_args, ref->peer_ref->name);
 906                 }
 907         }
 908
 909         if (get_exporter(transport, &exporter, &revlist_args))
 910                 die("Couldn't run fast-export");
 911
 912         string_list_clear(&revlist_args, 1);
 913
 914         if (finish_command(&exporter))
 915                 die("Error while running fast-export");
 916         if (push_update_refs_status(data, remote_refs, flags))
 917                 return 1;
 918
 919         if (data->export_marks) {
 920                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 921                 rename(buf.buf, data->export_marks);
 922                 strbuf_release(&buf);
 923         }
 924
 925         return 0;
 926 }
 927
 928 static int push_refs(struct transport *transport,
 929                 struct ref *remote_refs, int flags)
 930 {
 931         struct helper_data *data = transport->data;
 932
 933         if (process_connect(transport, 1)) {
 934                 do_take_over(transport);
 935                 return transport->push_refs(transport, remote_refs, flags);
 936         }
 937
 938         if (!remote_refs) {
 939                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 940                         "Perhaps you should specify a branch such as 'master'.\n");
 941                 return 0;
 942         }
 943
 944         if (data->push)
 945                 return push_refs_with_push(transport, remote_refs, flags);
 946
 947         if (data->export)
 948                 return push_refs_with_export(transport, remote_refs, flags);
 949
 950         return -1;
 951 }
 952
 953
 954 static int has_attribute(const char *attrs, const char *attr) {
 955         int len;
 956         if (!attrs)
 957                 return 0;
 958
 959         len = strlen(attr);
 960         for (;;) {
 961                 const char *space = strchrnul(attrs, ' ');
 962                 if (len == space - attrs && !strncmp(attrs, attr, len))
 963                         return 1;
 964                 if (!*space)
 965                         return 0;
 966                 attrs = space + 1;
 967         }
 968 }
 969
 970 static struct ref *get_refs_list(struct transport *transport, int for_push)
 971 {
 972         struct helper_data *data = transport->data;
 973         struct child_process *helper;
 974         struct ref *ret = NULL;
 975         struct ref **tail = &ret;
 976         struct ref *posn;
 977         struct strbuf buf = STRBUF_INIT;
 978
 979         helper = get_helper(transport);
 980
 981         if (process_connect(transport, for_push)) {
 982                 do_take_over(transport);
 983                 return transport->get_refs_list(transport, for_push);
 984         }
 985
 986         if (data->push && for_push)
 987                 write_str_in_full(helper->in, "list for-push\n");
 988         else
 989                 write_str_in_full(helper->in, "list\n");
 990
 991         while (1) {
 992                 char *eov, *eon;
 993                 if (recvline(data, &buf))
 994                         exit(128);
 995
 996                 if (!*buf.buf)
 997                         break;
 998
 999                 eov = strchr(buf.buf, ' ');
1000                 if (!eov)
1001                         die("Malformed response in ref list: %s", buf.buf);
1002                 eon = strchr(eov + 1, ' ');
1003                 *eov = '\0';
1004                 if (eon)
1005                         *eon = '\0';
1006                 *tail = alloc_ref(eov + 1);
1007                 if (buf.buf[0] == '@')
1008                         (*tail)->symref = xstrdup(buf.buf + 1);
1009                 else if (buf.buf[0] != '?')
1010                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1011                 if (eon) {
1012                         if (has_attribute(eon + 1, "unchanged")) {
1013                                 (*tail)->status |= REF_STATUS_UPTODATE;
1014                                 read_ref((*tail)->name, (*tail)->old_sha1);
1015                         }
1016                 }
1017                 tail = &((*tail)->next);
1018         }
1019         if (debug)
1020                 fprintf(stderr, "Debug: Read ref listing.\n");
1021         strbuf_release(&buf);
1022
1023         for (posn = ret; posn; posn = posn->next)
1024                 resolve_remote_symref(posn, ret);
1025
1026         return ret;
1027 }
1028
1029 int transport_helper_init(struct transport *transport, const char *name)
1030 {
1031         struct helper_data *data = xcalloc(1, sizeof(*data));
1032         data->name = name;
1033
1034         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1035                 debug = 1;
1036
1037         transport->data = data;
1038         transport->set_option = set_helper_option;
1039         transport->get_refs_list = get_refs_list;
1040         transport->fetch = fetch;
1041         transport->push_refs = push_refs;
1042         transport->disconnect = release_helper;
1043         transport->connect = connect_helper;
1044         transport->smart_options = &(data->transport_options);
1045         return 0;
1046 }
1047
1048 /*
1049  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1050  * buffer less), so attempt reads and writes with up to that size.
1051  */
1052 #define BUFFERSIZE 65536
1053 /* This should be enough to hold debugging message. */
1054 #define PBUFFERSIZE 8192
1055
1056 /* Print bidirectional transfer loop debug message. */
1057 __attribute__((format (printf, 1, 2)))
1058 static void transfer_debug(const char *fmt, ...)
1059 {
1060         va_list args;
1061         char msgbuf[PBUFFERSIZE];
1062         static int debug_enabled = -1;
1063
1064         if (debug_enabled < 0)
1065                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1066         if (!debug_enabled)
1067                 return;
1068
1069         va_start(args, fmt);
1070         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1071         va_end(args);
1072         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1073 }
1074
1075 /* Stream state: More data may be coming in this direction. */
1076 #define SSTATE_TRANSFERING 0
1077 /*
1078  * Stream state: No more data coming in this direction, flushing rest of
1079  * data.
1080  */
1081 #define SSTATE_FLUSHING 1
1082 /* Stream state: Transfer in this direction finished. */
1083 #define SSTATE_FINISHED 2
1084
1085 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1086 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1087 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1088
1089 /* Unidirectional transfer. */
1090 struct unidirectional_transfer {
1091         /* Source */
1092         int src;
1093         /* Destination */
1094         int dest;
1095         /* Is source socket? */
1096         int src_is_sock;
1097         /* Is destination socket? */
1098         int dest_is_sock;
1099         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1100         int state;
1101         /* Buffer. */
1102         char buf[BUFFERSIZE];
1103         /* Buffer used. */
1104         size_t bufuse;
1105         /* Name of source. */
1106         const char *src_name;
1107         /* Name of destination. */
1108         const char *dest_name;
1109 };
1110
1111 /* Closes the target (for writing) if transfer has finished. */
1112 static void udt_close_if_finished(struct unidirectional_transfer *t)
1113 {
1114         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1115                 t->state = SSTATE_FINISHED;
1116                 if (t->dest_is_sock)
1117                         shutdown(t->dest, SHUT_WR);
1118                 else
1119                         close(t->dest);
1120                 transfer_debug("Closed %s.", t->dest_name);
1121         }
1122 }
1123
1124 /*
1125  * Tries to read read data from source into buffer. If buffer is full,
1126  * no data is read. Returns 0 on success, -1 on error.
1127  */
1128 static int udt_do_read(struct unidirectional_transfer *t)
1129 {
1130         ssize_t bytes;
1131
1132         if (t->bufuse == BUFFERSIZE)
1133                 return 0;       /* No space for more. */
1134
1135         transfer_debug("%s is readable", t->src_name);
1136         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1137         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1138                 errno != EINTR) {
1139                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1140                 return -1;
1141         } else if (bytes == 0) {
1142                 transfer_debug("%s EOF (with %i bytes in buffer)",
1143                         t->src_name, (int)t->bufuse);
1144                 t->state = SSTATE_FLUSHING;
1145         } else if (bytes > 0) {
1146                 t->bufuse += bytes;
1147                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1148                         (int)bytes, t->src_name, (int)t->bufuse);
1149         }
1150         return 0;
1151 }
1152
1153 /* Tries to write data from buffer into destination. If buffer is empty,
1154  * no data is written. Returns 0 on success, -1 on error.
1155  */
1156 static int udt_do_write(struct unidirectional_transfer *t)
1157 {
1158         ssize_t bytes;
1159
1160         if (t->bufuse == 0)
1161                 return 0;       /* Nothing to write. */
1162
1163         transfer_debug("%s is writable", t->dest_name);
1164         bytes = xwrite(t->dest, t->buf, t->bufuse);
1165         if (bytes < 0 && errno != EWOULDBLOCK) {
1166                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1167                 return -1;
1168         } else if (bytes > 0) {
1169                 t->bufuse -= bytes;
1170                 if (t->bufuse)
1171                         memmove(t->buf, t->buf + bytes, t->bufuse);
1172                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1173                         (int)bytes, t->dest_name, (int)t->bufuse);
1174         }
1175         return 0;
1176 }
1177
1178
1179 /* State of bidirectional transfer loop. */
1180 struct bidirectional_transfer_state {
1181         /* Direction from program to git. */
1182         struct unidirectional_transfer ptg;
1183         /* Direction from git to program. */
1184         struct unidirectional_transfer gtp;
1185 };
1186
1187 static void *udt_copy_task_routine(void *udt)
1188 {
1189         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1190         while (t->state != SSTATE_FINISHED) {
1191                 if (STATE_NEEDS_READING(t->state))
1192                         if (udt_do_read(t))
1193                                 return NULL;
1194                 if (STATE_NEEDS_WRITING(t->state))
1195                         if (udt_do_write(t))
1196                                 return NULL;
1197                 if (STATE_NEEDS_CLOSING(t->state))
1198                         udt_close_if_finished(t);
1199         }
1200         return udt;     /* Just some non-NULL value. */
1201 }
1202
1203 #ifndef NO_PTHREADS
1204
1205 /*
1206  * Join thread, with appropriate errors on failure. Name is name for the
1207  * thread (for error messages). Returns 0 on success, 1 on failure.
1208  */
1209 static int tloop_join(pthread_t thread, const char *name)
1210 {
1211         int err;
1212         void *tret;
1213         err = pthread_join(thread, &tret);
1214         if (!tret) {
1215                 error("%s thread failed", name);
1216                 return 1;
1217         }
1218         if (err) {
1219                 error("%s thread failed to join: %s", name, strerror(err));
1220                 return 1;
1221         }
1222         return 0;
1223 }
1224
1225 /*
1226  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1227  * -1 on failure.
1228  */
1229 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1230 {
1231         pthread_t gtp_thread;
1232         pthread_t ptg_thread;
1233         int err;
1234         int ret = 0;
1235         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1236                 &s->gtp);
1237         if (err)
1238                 die("Can't start thread for copying data: %s", strerror(err));
1239         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1240                 &s->ptg);
1241         if (err)
1242                 die("Can't start thread for copying data: %s", strerror(err));
1243
1244         ret |= tloop_join(gtp_thread, "Git to program copy");
1245         ret |= tloop_join(ptg_thread, "Program to git copy");
1246         return ret;
1247 }
1248 #else
1249
1250 /* Close the source and target (for writing) for transfer. */
1251 static void udt_kill_transfer(struct unidirectional_transfer *t)
1252 {
1253         t->state = SSTATE_FINISHED;
1254         /*
1255          * Socket read end left open isn't a disaster if nobody
1256          * attempts to read from it (mingw compat headers do not
1257          * have SHUT_RD)...
1258          *
1259          * We can't fully close the socket since otherwise gtp
1260          * task would first close the socket it sends data to
1261          * while closing the ptg file descriptors.
1262          */
1263         if (!t->src_is_sock)
1264                 close(t->src);
1265         if (t->dest_is_sock)
1266                 shutdown(t->dest, SHUT_WR);
1267         else
1268                 close(t->dest);
1269 }
1270
1271 /*
1272  * Join process, with appropriate errors on failure. Name is name for the
1273  * process (for error messages). Returns 0 on success, 1 on failure.
1274  */
1275 static int tloop_join(pid_t pid, const char *name)
1276 {
1277         int tret;
1278         if (waitpid(pid, &tret, 0) < 0) {
1279                 error("%s process failed to wait: %s", name, strerror(errno));
1280                 return 1;
1281         }
1282         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1283                 error("%s process failed", name);
1284                 return 1;
1285         }
1286         return 0;
1287 }
1288
1289 /*
1290  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1291  * -1 on failure.
1292  */
1293 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1294 {
1295         pid_t pid1, pid2;
1296         int ret = 0;
1297
1298         /* Fork thread #1: git to program. */
1299         pid1 = fork();
1300         if (pid1 < 0)
1301                 die_errno("Can't start thread for copying data");
1302         else if (pid1 == 0) {
1303                 udt_kill_transfer(&s->ptg);
1304                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1305         }
1306
1307         /* Fork thread #2: program to git. */
1308         pid2 = fork();
1309         if (pid2 < 0)
1310                 die_errno("Can't start thread for copying data");
1311         else if (pid2 == 0) {
1312                 udt_kill_transfer(&s->gtp);
1313                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1314         }
1315
1316         /*
1317          * Close both streams in parent as to not interfere with
1318          * end of file detection and wait for both tasks to finish.
1319          */
1320         udt_kill_transfer(&s->gtp);
1321         udt_kill_transfer(&s->ptg);
1322         ret |= tloop_join(pid1, "Git to program copy");
1323         ret |= tloop_join(pid2, "Program to git copy");
1324         return ret;
1325 }
1326 #endif
1327
1328 /*
1329  * Copies data from stdin to output and from input to stdout simultaneously.
1330  * Additionally filtering through given filter. If filter is NULL, uses
1331  * identity filter.
1332  */
1333 int bidirectional_transfer_loop(int input, int output)
1334 {
1335         struct bidirectional_transfer_state state;
1336
1337         /* Fill the state fields. */
1338         state.ptg.src = input;
1339         state.ptg.dest = 1;
1340         state.ptg.src_is_sock = (input == output);
1341         state.ptg.dest_is_sock = 0;
1342         state.ptg.state = SSTATE_TRANSFERING;
1343         state.ptg.bufuse = 0;
1344         state.ptg.src_name = "remote input";
1345         state.ptg.dest_name = "stdout";
1346
1347         state.gtp.src = 0;
1348         state.gtp.dest = output;
1349         state.gtp.src_is_sock = 0;
1350         state.gtp.dest_is_sock = (input == output);
1351         state.gtp.state = SSTATE_TRANSFERING;
1352         state.gtp.bufuse = 0;
1353         state.gtp.src_name = "stdin";
1354         state.gtp.dest_name = "remote output";
1355
1356         return tloop_spawnwait_tasks(&state);
1357 }