transport-helper.c

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