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 "remote.h"
   9 #include "string-list.h"
  10 #include "thread-utils.h"
  11 #include "sigchain.h"
  12 #include "argv-array.h"
  13 #include "refs.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                 check_connectivity : 1,
  30                 no_disconnect_req : 1,
  31                 no_private_update : 1;
  32         char *export_marks;
  33         char *import_marks;
  34         /* These go from remote name (as in "list") to private name */
  35         struct refspec *refspecs;
  36         int refspec_nr;
  37         /* Transport options for fetch-pack/send-pack (should one of
  38          * those be invoked).
  39          */
  40         struct git_transport_options transport_options;
  41 };
  42
  43 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  44 {
  45         if (debug)
  46                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  47         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  48                 != buffer->len)
  49                 die_errno("Full write to remote helper failed");
  50 }
  51
  52 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  53 {
  54         strbuf_reset(buffer);
  55         if (debug)
  56                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  57         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  58                 if (debug)
  59                         fprintf(stderr, "Debug: Remote helper quit.\n");
  60                 return 1;
  61         }
  62
  63         if (debug)
  64                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  65         return 0;
  66 }
  67
  68 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  69 {
  70         return recvline_fh(helper->out, buffer, helper->name);
  71 }
  72
  73 static void write_constant(int fd, const char *str)
  74 {
  75         if (debug)
  76                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  77         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  78                 die_errno("Full write to remote helper failed");
  79 }
  80
  81 static const char *remove_ext_force(const char *url)
  82 {
  83         if (url) {
  84                 const char *colon = strchr(url, ':');
  85                 if (colon && colon[1] == ':')
  86                         return colon + 2;
  87         }
  88         return url;
  89 }
  90
  91 static void do_take_over(struct transport *transport)
  92 {
  93         struct helper_data *data;
  94         data = (struct helper_data *)transport->data;
  95         transport_take_over(transport, data->helper);
  96         fclose(data->out);
  97         free(data);
  98 }
  99
 100 static void standard_options(struct transport *t);
 101
 102 static struct child_process *get_helper(struct transport *transport)
 103 {
 104         struct helper_data *data = transport->data;
 105         struct strbuf buf = STRBUF_INIT;
 106         struct child_process *helper;
 107         const char **refspecs = NULL;
 108         int refspec_nr = 0;
 109         int refspec_alloc = 0;
 110         int duped;
 111         int code;
 112
 113         if (data->helper)
 114                 return data->helper;
 115
 116         helper = xmalloc(sizeof(*helper));
 117         child_process_init(helper);
 118         helper->in = -1;
 119         helper->out = -1;
 120         helper->err = 0;
 121         argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 122         argv_array_push(&helper->args, transport->remote->name);
 123         argv_array_push(&helper->args, remove_ext_force(transport->url));
 124         helper->git_cmd = 0;
 125         helper->silent_exec_failure = 1;
 126
 127         argv_array_pushf(&helper->env_array, "%s=%s", GIT_DIR_ENVIRONMENT,
 128                          get_git_dir());
 129
 130         code = start_command(helper);
 131         if (code < 0 && errno == ENOENT)
 132                 die("Unable to find remote helper for '%s'", data->name);
 133         else if (code != 0)
 134                 exit(code);
 135
 136         data->helper = helper;
 137         data->no_disconnect_req = 0;
 138
 139         /*
 140          * Open the output as FILE* so strbuf_getline() can be used.
 141          * Do this with duped fd because fclose() will close the fd,
 142          * and stuff like taking over will require the fd to remain.
 143          */
 144         duped = dup(helper->out);
 145         if (duped < 0)
 146                 die_errno("Can't dup helper output fd");
 147         data->out = xfdopen(duped, "r");
 148
 149         write_constant(helper->in, "capabilities\n");
 150
 151         while (1) {
 152                 const char *capname, *arg;
 153                 int mandatory = 0;
 154                 if (recvline(data, &buf))
 155                         exit(128);
 156
 157                 if (!*buf.buf)
 158                         break;
 159
 160                 if (*buf.buf == '*') {
 161                         capname = buf.buf + 1;
 162                         mandatory = 1;
 163                 } else
 164                         capname = buf.buf;
 165
 166                 if (debug)
 167                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 168                 if (!strcmp(capname, "fetch"))
 169                         data->fetch = 1;
 170                 else if (!strcmp(capname, "option"))
 171                         data->option = 1;
 172                 else if (!strcmp(capname, "push"))
 173                         data->push = 1;
 174                 else if (!strcmp(capname, "import"))
 175                         data->import = 1;
 176                 else if (!strcmp(capname, "bidi-import"))
 177                         data->bidi_import = 1;
 178                 else if (!strcmp(capname, "export"))
 179                         data->export = 1;
 180                 else if (!strcmp(capname, "check-connectivity"))
 181                         data->check_connectivity = 1;
 182                 else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 183                         ALLOC_GROW(refspecs,
 184                                    refspec_nr + 1,
 185                                    refspec_alloc);
 186                         refspecs[refspec_nr++] = xstrdup(arg);
 187                 } else if (!strcmp(capname, "connect")) {
 188                         data->connect = 1;
 189                 } else if (!strcmp(capname, "signed-tags")) {
 190                         data->signed_tags = 1;
 191                 } else if (skip_prefix(capname, "export-marks ", &arg)) {
 192                         data->export_marks = xstrdup(arg);
 193                 } else if (skip_prefix(capname, "import-marks ", &arg)) {
 194                         data->import_marks = xstrdup(arg);
 195                 } else if (starts_with(capname, "no-private-update")) {
 196                         data->no_private_update = 1;
 197                 } else if (mandatory) {
 198                         die("Unknown mandatory capability %s. This remote "
 199                             "helper probably needs newer version of Git.",
 200                             capname);
 201                 }
 202         }
 203         if (refspecs) {
 204                 int i;
 205                 data->refspec_nr = refspec_nr;
 206                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 207                 for (i = 0; i < refspec_nr; i++)
 208                         free((char *)refspecs[i]);
 209                 free(refspecs);
 210         } else if (data->import || data->bidi_import || data->export) {
 211                 warning("This remote helper should implement refspec capability.");
 212         }
 213         strbuf_release(&buf);
 214         if (debug)
 215                 fprintf(stderr, "Debug: Capabilities complete.\n");
 216         standard_options(transport);
 217         return data->helper;
 218 }
 219
 220 static int disconnect_helper(struct transport *transport)
 221 {
 222         struct helper_data *data = transport->data;
 223         int res = 0;
 224
 225         if (data->helper) {
 226                 if (debug)
 227                         fprintf(stderr, "Debug: Disconnecting.\n");
 228                 if (!data->no_disconnect_req) {
 229                         /*
 230                          * Ignore write errors; there's nothing we can do,
 231                          * since we're about to close the pipe anyway. And the
 232                          * most likely error is EPIPE due to the helper dying
 233                          * to report an error itself.
 234                          */
 235                         sigchain_push(SIGPIPE, SIG_IGN);
 236                         xwrite(data->helper->in, "\n", 1);
 237                         sigchain_pop(SIGPIPE);
 238                 }
 239                 close(data->helper->in);
 240                 close(data->helper->out);
 241                 fclose(data->out);
 242                 res = finish_command(data->helper);
 243                 free(data->helper);
 244                 data->helper = NULL;
 245         }
 246         return res;
 247 }
 248
 249 static const char *unsupported_options[] = {
 250         TRANS_OPT_UPLOADPACK,
 251         TRANS_OPT_RECEIVEPACK,
 252         TRANS_OPT_THIN,
 253         TRANS_OPT_KEEP
 254         };
 255
 256 static const char *boolean_options[] = {
 257         TRANS_OPT_THIN,
 258         TRANS_OPT_KEEP,
 259         TRANS_OPT_FOLLOWTAGS,
 260         TRANS_OPT_PUSH_CERT
 261         };
 262
 263 static int set_helper_option(struct transport *transport,
 264                           const char *name, const char *value)
 265 {
 266         struct helper_data *data = transport->data;
 267         struct strbuf buf = STRBUF_INIT;
 268         int i, ret, is_bool = 0;
 269
 270         get_helper(transport);
 271
 272         if (!data->option)
 273                 return 1;
 274
 275         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 276                 if (!strcmp(name, unsupported_options[i]))
 277                         return 1;
 278         }
 279
 280         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 281                 if (!strcmp(name, boolean_options[i])) {
 282                         is_bool = 1;
 283                         break;
 284                 }
 285         }
 286
 287         strbuf_addf(&buf, "option %s ", name);
 288         if (is_bool)
 289                 strbuf_addstr(&buf, value ? "true" : "false");
 290         else
 291                 quote_c_style(value, &buf, NULL, 0);
 292         strbuf_addch(&buf, '\n');
 293
 294         sendline(data, &buf);
 295         if (recvline(data, &buf))
 296                 exit(128);
 297
 298         if (!strcmp(buf.buf, "ok"))
 299                 ret = 0;
 300         else if (starts_with(buf.buf, "error")) {
 301                 ret = -1;
 302         } else if (!strcmp(buf.buf, "unsupported"))
 303                 ret = 1;
 304         else {
 305                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 306                 ret = 1;
 307         }
 308         strbuf_release(&buf);
 309         return ret;
 310 }
 311
 312 static void standard_options(struct transport *t)
 313 {
 314         char buf[16];
 315         int n;
 316         int v = t->verbose;
 317
 318         set_helper_option(t, "progress", t->progress ? "true" : "false");
 319
 320         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 321         if (n >= sizeof(buf))
 322                 die("impossibly large verbosity value");
 323         set_helper_option(t, "verbosity", buf);
 324 }
 325
 326 static int release_helper(struct transport *transport)
 327 {
 328         int res = 0;
 329         struct helper_data *data = transport->data;
 330         free_refspec(data->refspec_nr, data->refspecs);
 331         data->refspecs = NULL;
 332         res = disconnect_helper(transport);
 333         free(transport->data);
 334         return res;
 335 }
 336
 337 static int fetch_with_fetch(struct transport *transport,
 338                             int nr_heads, struct ref **to_fetch)
 339 {
 340         struct helper_data *data = transport->data;
 341         int i;
 342         struct strbuf buf = STRBUF_INIT;
 343
 344         for (i = 0; i < nr_heads; i++) {
 345                 const struct ref *posn = to_fetch[i];
 346                 if (posn->status & REF_STATUS_UPTODATE)
 347                         continue;
 348
 349                 strbuf_addf(&buf, "fetch %s %s\n",
 350                             sha1_to_hex(posn->old_sha1),
 351                             posn->symref ? posn->symref : posn->name);
 352         }
 353
 354         strbuf_addch(&buf, '\n');
 355         sendline(data, &buf);
 356
 357         while (1) {
 358                 if (recvline(data, &buf))
 359                         exit(128);
 360
 361                 if (starts_with(buf.buf, "lock ")) {
 362                         const char *name = buf.buf + 5;
 363                         if (transport->pack_lockfile)
 364                                 warning("%s also locked %s", data->name, name);
 365                         else
 366                                 transport->pack_lockfile = xstrdup(name);
 367                 }
 368                 else if (data->check_connectivity &&
 369                          data->transport_options.check_self_contained_and_connected &&
 370                          !strcmp(buf.buf, "connectivity-ok"))
 371                         data->transport_options.self_contained_and_connected = 1;
 372                 else if (!buf.len)
 373                         break;
 374                 else
 375                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 376         }
 377         strbuf_release(&buf);
 378         return 0;
 379 }
 380
 381 static int get_importer(struct transport *transport, struct child_process *fastimport)
 382 {
 383         struct child_process *helper = get_helper(transport);
 384         struct helper_data *data = transport->data;
 385         int cat_blob_fd, code;
 386         child_process_init(fastimport);
 387         fastimport->in = helper->out;
 388         argv_array_push(&fastimport->args, "fast-import");
 389         argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 390
 391         if (data->bidi_import) {
 392                 cat_blob_fd = xdup(helper->in);
 393                 argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 394         }
 395         fastimport->git_cmd = 1;
 396
 397         code = start_command(fastimport);
 398         return code;
 399 }
 400
 401 static int get_exporter(struct transport *transport,
 402                         struct child_process *fastexport,
 403                         struct string_list *revlist_args)
 404 {
 405         struct helper_data *data = transport->data;
 406         struct child_process *helper = get_helper(transport);
 407         int i;
 408
 409         child_process_init(fastexport);
 410
 411         /* we need to duplicate helper->in because we want to use it after
 412          * fastexport is done with it. */
 413         fastexport->out = dup(helper->in);
 414         argv_array_push(&fastexport->args, "fast-export");
 415         argv_array_push(&fastexport->args, "--use-done-feature");
 416         argv_array_push(&fastexport->args, data->signed_tags ?
 417                 "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 418         if (data->export_marks)
 419                 argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 420         if (data->import_marks)
 421                 argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 422
 423         for (i = 0; i < revlist_args->nr; i++)
 424                 argv_array_push(&fastexport->args, revlist_args->items[i].string);
 425
 426         fastexport->git_cmd = 1;
 427         return start_command(fastexport);
 428 }
 429
 430 static int fetch_with_import(struct transport *transport,
 431                              int nr_heads, struct ref **to_fetch)
 432 {
 433         struct child_process fastimport;
 434         struct helper_data *data = transport->data;
 435         int i;
 436         struct ref *posn;
 437         struct strbuf buf = STRBUF_INIT;
 438
 439         get_helper(transport);
 440
 441         if (get_importer(transport, &fastimport))
 442                 die("Couldn't run fast-import");
 443
 444         for (i = 0; i < nr_heads; i++) {
 445                 posn = to_fetch[i];
 446                 if (posn->status & REF_STATUS_UPTODATE)
 447                         continue;
 448
 449                 strbuf_addf(&buf, "import %s\n",
 450                             posn->symref ? posn->symref : posn->name);
 451                 sendline(data, &buf);
 452                 strbuf_reset(&buf);
 453         }
 454
 455         write_constant(data->helper->in, "\n");
 456         /*
 457          * remote-helpers that advertise the bidi-import capability are required to
 458          * buffer the complete batch of import commands until this newline before
 459          * sending data to fast-import.
 460          * These helpers read back data from fast-import on their stdin, which could
 461          * be mixed with import commands, otherwise.
 462          */
 463
 464         if (finish_command(&fastimport))
 465                 die("Error while running fast-import");
 466
 467         /*
 468          * The fast-import stream of a remote helper that advertises
 469          * the "refspec" capability writes to the refs named after the
 470          * right hand side of the first refspec matching each ref we
 471          * were fetching.
 472          *
 473          * (If no "refspec" capability was specified, for historical
 474          * reasons we default to the equivalent of *:*.)
 475          *
 476          * Store the result in to_fetch[i].old_sha1.  Callers such
 477          * as "git fetch" can use the value to write feedback to the
 478          * terminal, populate FETCH_HEAD, and determine what new value
 479          * should be written to peer_ref if the update is a
 480          * fast-forward or this is a forced update.
 481          */
 482         for (i = 0; i < nr_heads; i++) {
 483                 char *private, *name;
 484                 posn = to_fetch[i];
 485                 if (posn->status & REF_STATUS_UPTODATE)
 486                         continue;
 487                 name = posn->symref ? posn->symref : posn->name;
 488                 if (data->refspecs)
 489                         private = apply_refspecs(data->refspecs, data->refspec_nr, name);
 490                 else
 491                         private = xstrdup(name);
 492                 if (private) {
 493                         read_ref(private, posn->old_sha1);
 494                         free(private);
 495                 }
 496         }
 497         strbuf_release(&buf);
 498         return 0;
 499 }
 500
 501 static int process_connect_service(struct transport *transport,
 502                                    const char *name, const char *exec)
 503 {
 504         struct helper_data *data = transport->data;
 505         struct strbuf cmdbuf = STRBUF_INIT;
 506         struct child_process *helper;
 507         int r, duped, ret = 0;
 508         FILE *input;
 509
 510         helper = get_helper(transport);
 511
 512         /*
 513          * Yes, dup the pipe another time, as we need unbuffered version
 514          * of input pipe as FILE*. fclose() closes the underlying fd and
 515          * stream buffering only can be changed before first I/O operation
 516          * on it.
 517          */
 518         duped = dup(helper->out);
 519         if (duped < 0)
 520                 die_errno("Can't dup helper output fd");
 521         input = xfdopen(duped, "r");
 522         setvbuf(input, NULL, _IONBF, 0);
 523
 524         /*
 525          * Handle --upload-pack and friends. This is fire and forget...
 526          * just warn if it fails.
 527          */
 528         if (strcmp(name, exec)) {
 529                 r = set_helper_option(transport, "servpath", exec);
 530                 if (r > 0)
 531                         warning("Setting remote service path not supported by protocol.");
 532                 else if (r < 0)
 533                         warning("Invalid remote service path.");
 534         }
 535
 536         if (data->connect)
 537                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 538         else
 539                 goto exit;
 540
 541         sendline(data, &cmdbuf);
 542         if (recvline_fh(input, &cmdbuf, name))
 543                 exit(128);
 544
 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->check_connectivity &&
 618             data->transport_options.check_self_contained_and_connected)
 619                 set_helper_option(transport, "check-connectivity", "true");
 620
 621         if (transport->cloning)
 622                 set_helper_option(transport, "cloning", "true");
 623
 624         if (data->transport_options.update_shallow)
 625                 set_helper_option(transport, "update-shallow", "true");
 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         for_each_string_list_item(cas_option, &cas_options)
 832                 set_helper_option(transport, "cas", cas_option->string);
 833
 834         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 835                 if (set_helper_option(transport, "dry-run", "true") != 0)
 836                         die("helper %s does not support dry-run", data->name);
 837         } else if (flags & TRANSPORT_PUSH_CERT) {
 838                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 839                         die("helper %s does not support --signed", data->name);
 840         }
 841
 842         strbuf_addch(&buf, '\n');
 843         sendline(data, &buf);
 844         strbuf_release(&buf);
 845
 846         return push_update_refs_status(data, remote_refs, flags);
 847 }
 848
 849 static int push_refs_with_export(struct transport *transport,
 850                 struct ref *remote_refs, int flags)
 851 {
 852         struct ref *ref;
 853         struct child_process *helper, exporter;
 854         struct helper_data *data = transport->data;
 855         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 856         struct strbuf buf = STRBUF_INIT;
 857
 858         if (!data->refspecs)
 859                 die("remote-helper doesn't support push; refspec needed");
 860
 861         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 862                 if (set_helper_option(transport, "dry-run", "true") != 0)
 863                         die("helper %s does not support dry-run", data->name);
 864         } else if (flags & TRANSPORT_PUSH_CERT) {
 865                 if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
 866                         die("helper %s does not support --signed", data->name);
 867         }
 868
 869         if (flags & TRANSPORT_PUSH_FORCE) {
 870                 if (set_helper_option(transport, "force", "true") != 0)
 871                         warning("helper %s does not support 'force'", data->name);
 872         }
 873
 874         helper = get_helper(transport);
 875
 876         write_constant(helper->in, "export\n");
 877
 878         for (ref = remote_refs; ref; ref = ref->next) {
 879                 char *private;
 880                 unsigned char sha1[20];
 881
 882                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 883                 if (private && !get_sha1(private, sha1)) {
 884                         strbuf_addf(&buf, "^%s", private);
 885                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 886                         hashcpy(ref->old_sha1, sha1);
 887                 }
 888                 free(private);
 889
 890                 if (ref->peer_ref) {
 891                         if (strcmp(ref->name, ref->peer_ref->name)) {
 892                                 if (!ref->deletion) {
 893                                         const char *name;
 894                                         int flag;
 895
 896                                         /* Follow symbolic refs (mainly for HEAD). */
 897                                         name = resolve_ref_unsafe(
 898                                                  ref->peer_ref->name,
 899                                                  RESOLVE_REF_READING,
 900                                                  sha1, &flag);
 901                                         if (!name || !(flag & REF_ISSYMREF))
 902                                                 name = ref->peer_ref->name;
 903
 904                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 905                                 } else
 906                                         strbuf_addf(&buf, ":%s", ref->name);
 907
 908                                 string_list_append(&revlist_args, "--refspec");
 909                                 string_list_append(&revlist_args, buf.buf);
 910                                 strbuf_release(&buf);
 911                         }
 912                         if (!ref->deletion)
 913                                 string_list_append(&revlist_args, ref->peer_ref->name);
 914                 }
 915         }
 916
 917         if (get_exporter(transport, &exporter, &revlist_args))
 918                 die("Couldn't run fast-export");
 919
 920         string_list_clear(&revlist_args, 1);
 921
 922         if (finish_command(&exporter))
 923                 die("Error while running fast-export");
 924         if (push_update_refs_status(data, remote_refs, flags))
 925                 return 1;
 926
 927         if (data->export_marks) {
 928                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 929                 rename(buf.buf, data->export_marks);
 930                 strbuf_release(&buf);
 931         }
 932
 933         return 0;
 934 }
 935
 936 static int push_refs(struct transport *transport,
 937                 struct ref *remote_refs, int flags)
 938 {
 939         struct helper_data *data = transport->data;
 940
 941         if (process_connect(transport, 1)) {
 942                 do_take_over(transport);
 943                 return transport->push_refs(transport, remote_refs, flags);
 944         }
 945
 946         if (!remote_refs) {
 947                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 948                         "Perhaps you should specify a branch such as 'master'.\n");
 949                 return 0;
 950         }
 951
 952         if (data->push)
 953                 return push_refs_with_push(transport, remote_refs, flags);
 954
 955         if (data->export)
 956                 return push_refs_with_export(transport, remote_refs, flags);
 957
 958         return -1;
 959 }
 960
 961
 962 static int has_attribute(const char *attrs, const char *attr) {
 963         int len;
 964         if (!attrs)
 965                 return 0;
 966
 967         len = strlen(attr);
 968         for (;;) {
 969                 const char *space = strchrnul(attrs, ' ');
 970                 if (len == space - attrs && !strncmp(attrs, attr, len))
 971                         return 1;
 972                 if (!*space)
 973                         return 0;
 974                 attrs = space + 1;
 975         }
 976 }
 977
 978 static struct ref *get_refs_list(struct transport *transport, int for_push)
 979 {
 980         struct helper_data *data = transport->data;
 981         struct child_process *helper;
 982         struct ref *ret = NULL;
 983         struct ref **tail = &ret;
 984         struct ref *posn;
 985         struct strbuf buf = STRBUF_INIT;
 986
 987         helper = get_helper(transport);
 988
 989         if (process_connect(transport, for_push)) {
 990                 do_take_over(transport);
 991                 return transport->get_refs_list(transport, for_push);
 992         }
 993
 994         if (data->push && for_push)
 995                 write_str_in_full(helper->in, "list for-push\n");
 996         else
 997                 write_str_in_full(helper->in, "list\n");
 998
 999         while (1) {
1000                 char *eov, *eon;
1001                 if (recvline(data, &buf))
1002                         exit(128);
1003
1004                 if (!*buf.buf)
1005                         break;
1006
1007                 eov = strchr(buf.buf, ' ');
1008                 if (!eov)
1009                         die("Malformed response in ref list: %s", buf.buf);
1010                 eon = strchr(eov + 1, ' ');
1011                 *eov = '\0';
1012                 if (eon)
1013                         *eon = '\0';
1014                 *tail = alloc_ref(eov + 1);
1015                 if (buf.buf[0] == '@')
1016                         (*tail)->symref = xstrdup(buf.buf + 1);
1017                 else if (buf.buf[0] != '?')
1018                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1019                 if (eon) {
1020                         if (has_attribute(eon + 1, "unchanged")) {
1021                                 (*tail)->status |= REF_STATUS_UPTODATE;
1022                                 read_ref((*tail)->name, (*tail)->old_sha1);
1023                         }
1024                 }
1025                 tail = &((*tail)->next);
1026         }
1027         if (debug)
1028                 fprintf(stderr, "Debug: Read ref listing.\n");
1029         strbuf_release(&buf);
1030
1031         for (posn = ret; posn; posn = posn->next)
1032                 resolve_remote_symref(posn, ret);
1033
1034         return ret;
1035 }
1036
1037 int transport_helper_init(struct transport *transport, const char *name)
1038 {
1039         struct helper_data *data = xcalloc(1, sizeof(*data));
1040         data->name = name;
1041
1042         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1043                 debug = 1;
1044
1045         transport->data = data;
1046         transport->set_option = set_helper_option;
1047         transport->get_refs_list = get_refs_list;
1048         transport->fetch = fetch;
1049         transport->push_refs = push_refs;
1050         transport->disconnect = release_helper;
1051         transport->connect = connect_helper;
1052         transport->smart_options = &(data->transport_options);
1053         return 0;
1054 }
1055
1056 /*
1057  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1058  * buffer less), so attempt reads and writes with up to that size.
1059  */
1060 #define BUFFERSIZE 65536
1061 /* This should be enough to hold debugging message. */
1062 #define PBUFFERSIZE 8192
1063
1064 /* Print bidirectional transfer loop debug message. */
1065 __attribute__((format (printf, 1, 2)))
1066 static void transfer_debug(const char *fmt, ...)
1067 {
1068         va_list args;
1069         char msgbuf[PBUFFERSIZE];
1070         static int debug_enabled = -1;
1071
1072         if (debug_enabled < 0)
1073                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1074         if (!debug_enabled)
1075                 return;
1076
1077         va_start(args, fmt);
1078         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1079         va_end(args);
1080         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1081 }
1082
1083 /* Stream state: More data may be coming in this direction. */
1084 #define SSTATE_TRANSFERING 0
1085 /*
1086  * Stream state: No more data coming in this direction, flushing rest of
1087  * data.
1088  */
1089 #define SSTATE_FLUSHING 1
1090 /* Stream state: Transfer in this direction finished. */
1091 #define SSTATE_FINISHED 2
1092
1093 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1094 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1095 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1096
1097 /* Unidirectional transfer. */
1098 struct unidirectional_transfer {
1099         /* Source */
1100         int src;
1101         /* Destination */
1102         int dest;
1103         /* Is source socket? */
1104         int src_is_sock;
1105         /* Is destination socket? */
1106         int dest_is_sock;
1107         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1108         int state;
1109         /* Buffer. */
1110         char buf[BUFFERSIZE];
1111         /* Buffer used. */
1112         size_t bufuse;
1113         /* Name of source. */
1114         const char *src_name;
1115         /* Name of destination. */
1116         const char *dest_name;
1117 };
1118
1119 /* Closes the target (for writing) if transfer has finished. */
1120 static void udt_close_if_finished(struct unidirectional_transfer *t)
1121 {
1122         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1123                 t->state = SSTATE_FINISHED;
1124                 if (t->dest_is_sock)
1125                         shutdown(t->dest, SHUT_WR);
1126                 else
1127                         close(t->dest);
1128                 transfer_debug("Closed %s.", t->dest_name);
1129         }
1130 }
1131
1132 /*
1133  * Tries to read read data from source into buffer. If buffer is full,
1134  * no data is read. Returns 0 on success, -1 on error.
1135  */
1136 static int udt_do_read(struct unidirectional_transfer *t)
1137 {
1138         ssize_t bytes;
1139
1140         if (t->bufuse == BUFFERSIZE)
1141                 return 0;       /* No space for more. */
1142
1143         transfer_debug("%s is readable", t->src_name);
1144         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1145         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1146                 errno != EINTR) {
1147                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1148                 return -1;
1149         } else if (bytes == 0) {
1150                 transfer_debug("%s EOF (with %i bytes in buffer)",
1151                         t->src_name, (int)t->bufuse);
1152                 t->state = SSTATE_FLUSHING;
1153         } else if (bytes > 0) {
1154                 t->bufuse += bytes;
1155                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1156                         (int)bytes, t->src_name, (int)t->bufuse);
1157         }
1158         return 0;
1159 }
1160
1161 /* Tries to write data from buffer into destination. If buffer is empty,
1162  * no data is written. Returns 0 on success, -1 on error.
1163  */
1164 static int udt_do_write(struct unidirectional_transfer *t)
1165 {
1166         ssize_t bytes;
1167
1168         if (t->bufuse == 0)
1169                 return 0;       /* Nothing to write. */
1170
1171         transfer_debug("%s is writable", t->dest_name);
1172         bytes = xwrite(t->dest, t->buf, t->bufuse);
1173         if (bytes < 0 && errno != EWOULDBLOCK) {
1174                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1175                 return -1;
1176         } else if (bytes > 0) {
1177                 t->bufuse -= bytes;
1178                 if (t->bufuse)
1179                         memmove(t->buf, t->buf + bytes, t->bufuse);
1180                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1181                         (int)bytes, t->dest_name, (int)t->bufuse);
1182         }
1183         return 0;
1184 }
1185
1186
1187 /* State of bidirectional transfer loop. */
1188 struct bidirectional_transfer_state {
1189         /* Direction from program to git. */
1190         struct unidirectional_transfer ptg;
1191         /* Direction from git to program. */
1192         struct unidirectional_transfer gtp;
1193 };
1194
1195 static void *udt_copy_task_routine(void *udt)
1196 {
1197         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1198         while (t->state != SSTATE_FINISHED) {
1199                 if (STATE_NEEDS_READING(t->state))
1200                         if (udt_do_read(t))
1201                                 return NULL;
1202                 if (STATE_NEEDS_WRITING(t->state))
1203                         if (udt_do_write(t))
1204                                 return NULL;
1205                 if (STATE_NEEDS_CLOSING(t->state))
1206                         udt_close_if_finished(t);
1207         }
1208         return udt;     /* Just some non-NULL value. */
1209 }
1210
1211 #ifndef NO_PTHREADS
1212
1213 /*
1214  * Join thread, with appropriate errors on failure. Name is name for the
1215  * thread (for error messages). Returns 0 on success, 1 on failure.
1216  */
1217 static int tloop_join(pthread_t thread, const char *name)
1218 {
1219         int err;
1220         void *tret;
1221         err = pthread_join(thread, &tret);
1222         if (!tret) {
1223                 error("%s thread failed", name);
1224                 return 1;
1225         }
1226         if (err) {
1227                 error("%s thread failed to join: %s", name, strerror(err));
1228                 return 1;
1229         }
1230         return 0;
1231 }
1232
1233 /*
1234  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1235  * -1 on failure.
1236  */
1237 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1238 {
1239         pthread_t gtp_thread;
1240         pthread_t ptg_thread;
1241         int err;
1242         int ret = 0;
1243         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1244                 &s->gtp);
1245         if (err)
1246                 die("Can't start thread for copying data: %s", strerror(err));
1247         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1248                 &s->ptg);
1249         if (err)
1250                 die("Can't start thread for copying data: %s", strerror(err));
1251
1252         ret |= tloop_join(gtp_thread, "Git to program copy");
1253         ret |= tloop_join(ptg_thread, "Program to git copy");
1254         return ret;
1255 }
1256 #else
1257
1258 /* Close the source and target (for writing) for transfer. */
1259 static void udt_kill_transfer(struct unidirectional_transfer *t)
1260 {
1261         t->state = SSTATE_FINISHED;
1262         /*
1263          * Socket read end left open isn't a disaster if nobody
1264          * attempts to read from it (mingw compat headers do not
1265          * have SHUT_RD)...
1266          *
1267          * We can't fully close the socket since otherwise gtp
1268          * task would first close the socket it sends data to
1269          * while closing the ptg file descriptors.
1270          */
1271         if (!t->src_is_sock)
1272                 close(t->src);
1273         if (t->dest_is_sock)
1274                 shutdown(t->dest, SHUT_WR);
1275         else
1276                 close(t->dest);
1277 }
1278
1279 /*
1280  * Join process, with appropriate errors on failure. Name is name for the
1281  * process (for error messages). Returns 0 on success, 1 on failure.
1282  */
1283 static int tloop_join(pid_t pid, const char *name)
1284 {
1285         int tret;
1286         if (waitpid(pid, &tret, 0) < 0) {
1287                 error("%s process failed to wait: %s", name, strerror(errno));
1288                 return 1;
1289         }
1290         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1291                 error("%s process failed", name);
1292                 return 1;
1293         }
1294         return 0;
1295 }
1296
1297 /*
1298  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1299  * -1 on failure.
1300  */
1301 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1302 {
1303         pid_t pid1, pid2;
1304         int ret = 0;
1305
1306         /* Fork thread #1: git to program. */
1307         pid1 = fork();
1308         if (pid1 < 0)
1309                 die_errno("Can't start thread for copying data");
1310         else if (pid1 == 0) {
1311                 udt_kill_transfer(&s->ptg);
1312                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1313         }
1314
1315         /* Fork thread #2: program to git. */
1316         pid2 = fork();
1317         if (pid2 < 0)
1318                 die_errno("Can't start thread for copying data");
1319         else if (pid2 == 0) {
1320                 udt_kill_transfer(&s->gtp);
1321                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1322         }
1323
1324         /*
1325          * Close both streams in parent as to not interfere with
1326          * end of file detection and wait for both tasks to finish.
1327          */
1328         udt_kill_transfer(&s->gtp);
1329         udt_kill_transfer(&s->ptg);
1330         ret |= tloop_join(pid1, "Git to program copy");
1331         ret |= tloop_join(pid2, "Program to git copy");
1332         return ret;
1333 }
1334 #endif
1335
1336 /*
1337  * Copies data from stdin to output and from input to stdout simultaneously.
1338  * Additionally filtering through given filter. If filter is NULL, uses
1339  * identity filter.
1340  */
1341 int bidirectional_transfer_loop(int input, int output)
1342 {
1343         struct bidirectional_transfer_state state;
1344
1345         /* Fill the state fields. */
1346         state.ptg.src = input;
1347         state.ptg.dest = 1;
1348         state.ptg.src_is_sock = (input == output);
1349         state.ptg.dest_is_sock = 0;
1350         state.ptg.state = SSTATE_TRANSFERING;
1351         state.ptg.bufuse = 0;
1352         state.ptg.src_name = "remote input";
1353         state.ptg.dest_name = "stdout";
1354
1355         state.gtp.src = 0;
1356         state.gtp.dest = output;
1357         state.gtp.src_is_sock = 0;
1358         state.gtp.dest_is_sock = (input == output);
1359         state.gtp.state = SSTATE_TRANSFERING;
1360         state.gtp.bufuse = 0;
1361         state.gtp.src_name = "stdin";
1362         state.gtp.dest_name = "remote output";
1363
1364         return tloop_spawnwait_tasks(&state);
1365 }