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