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

   1 #include "cache.h"
   2 #include "transport.h"
   3 #include "quote.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "quote.h"
   9 #include "remote.h"
  10 #include "string-list.h"
  11 #include "thread-utils.h"
  12 #include "sigchain.h"
  13 #include "argv-array.h"
  14 #include "refs.h"
  15
  16 static int debug;
  17
  18 struct helper_data {
  19         const char *name;
  20         struct child_process *helper;
  21         FILE *out;
  22         unsigned fetch : 1,
  23                 import : 1,
  24                 bidi_import : 1,
  25                 export : 1,
  26                 option : 1,
  27                 push : 1,
  28                 connect : 1,
  29                 signed_tags : 1,
  30                 check_connectivity : 1,
  31                 no_disconnect_req : 1,
  32                 no_private_update : 1;
  33         char *export_marks;
  34         char *import_marks;
  35         /* These go from remote name (as in "list") to private name */
  36         struct refspec *refspecs;
  37         int refspec_nr;
  38         /* Transport options for fetch-pack/send-pack (should one of
  39          * those be invoked).
  40          */
  41         struct git_transport_options transport_options;
  42 };
  43
  44 static void sendline(struct helper_data *helper, struct strbuf *buffer)
  45 {
  46         if (debug)
  47                 fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  48         if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  49                 != buffer->len)
  50                 die_errno("Full write to remote helper failed");
  51 }
  52
  53 static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  54 {
  55         strbuf_reset(buffer);
  56         if (debug)
  57                 fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  58         if (strbuf_getline(buffer, helper, '\n') == EOF) {
  59                 if (debug)
  60                         fprintf(stderr, "Debug: Remote helper quit.\n");
  61                 return 1;
  62         }
  63
  64         if (debug)
  65                 fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  66         return 0;
  67 }
  68
  69 static int recvline(struct helper_data *helper, struct strbuf *buffer)
  70 {
  71         return recvline_fh(helper->out, buffer, helper->name);
  72 }
  73
  74 static void write_constant(int fd, const char *str)
  75 {
  76         if (debug)
  77                 fprintf(stderr, "Debug: Remote helper: -> %s", str);
  78         if (write_in_full(fd, str, strlen(str)) != strlen(str))
  79                 die_errno("Full write to remote helper failed");
  80 }
  81
  82 static const char *remove_ext_force(const char *url)
  83 {
  84         if (url) {
  85                 const char *colon = strchr(url, ':');
  86                 if (colon && colon[1] == ':')
  87                         return colon + 2;
  88         }
  89         return url;
  90 }
  91
  92 static void do_take_over(struct transport *transport)
  93 {
  94         struct helper_data *data;
  95         data = (struct helper_data *)transport->data;
  96         transport_take_over(transport, data->helper);
  97         fclose(data->out);
  98         free(data);
  99 }
 100
 101 static struct child_process *get_helper(struct transport *transport)
 102 {
 103         struct helper_data *data = transport->data;
 104         struct argv_array argv = ARGV_ARRAY_INIT;
 105         struct strbuf buf = STRBUF_INIT;
 106         struct child_process *helper;
 107         const char **refspecs = NULL;
 108         int refspec_nr = 0;
 109         int refspec_alloc = 0;
 110         int duped;
 111         int code;
 112         char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 113         const char *helper_env[] = {
 114                 git_dir_buf,
 115                 NULL
 116         };
 117
 118
 119         if (data->helper)
 120                 return data->helper;
 121
 122         helper = xcalloc(1, sizeof(*helper));
 123         helper->in = -1;
 124         helper->out = -1;
 125         helper->err = 0;
 126         argv_array_pushf(&argv, "git-remote-%s", data->name);
 127         argv_array_push(&argv, transport->remote->name);
 128         argv_array_push(&argv, remove_ext_force(transport->url));
 129         helper->argv = argv_array_detach(&argv, NULL);
 130         helper->git_cmd = 0;
 131         helper->silent_exec_failure = 1;
 132
 133         snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 134         helper->env = helper_env;
 135
 136         code = start_command(helper);
 137         if (code < 0 && errno == ENOENT)
 138                 die("Unable to find remote helper for '%s'", data->name);
 139         else if (code != 0)
 140                 exit(code);
 141
 142         data->helper = helper;
 143         data->no_disconnect_req = 0;
 144
 145         /*
 146          * Open the output as FILE* so strbuf_getline() can be used.
 147          * Do this with duped fd because fclose() will close the fd,
 148          * and stuff like taking over will require the fd to remain.
 149          */
 150         duped = dup(helper->out);
 151         if (duped < 0)
 152                 die_errno("Can't dup helper output fd");
 153         data->out = xfdopen(duped, "r");
 154
 155         write_constant(helper->in, "capabilities\n");
 156
 157         while (1) {
 158                 const char *capname;
 159                 int mandatory = 0;
 160                 if (recvline(data, &buf))
 161                         exit(128);
 162
 163                 if (!*buf.buf)
 164                         break;
 165
 166                 if (*buf.buf == '*') {
 167                         capname = buf.buf + 1;
 168                         mandatory = 1;
 169                 } else
 170                         capname = buf.buf;
 171
 172                 if (debug)
 173                         fprintf(stderr, "Debug: Got cap %s\n", capname);
 174                 if (!strcmp(capname, "fetch"))
 175                         data->fetch = 1;
 176                 else if (!strcmp(capname, "option"))
 177                         data->option = 1;
 178                 else if (!strcmp(capname, "push"))
 179                         data->push = 1;
 180                 else if (!strcmp(capname, "import"))
 181                         data->import = 1;
 182                 else if (!strcmp(capname, "bidi-import"))
 183                         data->bidi_import = 1;
 184                 else if (!strcmp(capname, "export"))
 185                         data->export = 1;
 186                 else if (!strcmp(capname, "check-connectivity"))
 187                         data->check_connectivity = 1;
 188                 else if (!data->refspecs && starts_with(capname, "refspec ")) {
 189                         ALLOC_GROW(refspecs,
 190                                    refspec_nr + 1,
 191                                    refspec_alloc);
 192                         refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 193                 } else if (!strcmp(capname, "connect")) {
 194                         data->connect = 1;
 195                 } else if (!strcmp(capname, "signed-tags")) {
 196                         data->signed_tags = 1;
 197                 } else if (starts_with(capname, "export-marks ")) {
 198                         data->export_marks = xstrdup(capname + strlen("export-marks "));
 199                 } else if (starts_with(capname, "import-marks")) {
 200                         data->import_marks = xstrdup(capname + strlen("import-marks "));
 201                 } else if (starts_with(capname, "no-private-update")) {
 202                         data->no_private_update = 1;
 203                 } else if (mandatory) {
 204                         die("Unknown mandatory capability %s. This remote "
 205                             "helper probably needs newer version of Git.",
 206                             capname);
 207                 }
 208         }
 209         if (refspecs) {
 210                 int i;
 211                 data->refspec_nr = refspec_nr;
 212                 data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 213                 for (i = 0; i < refspec_nr; i++)
 214                         free((char *)refspecs[i]);
 215                 free(refspecs);
 216         } else if (data->import || data->bidi_import || data->export) {
 217                 warning("This remote helper should implement refspec capability.");
 218         }
 219         strbuf_release(&buf);
 220         if (debug)
 221                 fprintf(stderr, "Debug: Capabilities complete.\n");
 222         return data->helper;
 223 }
 224
 225 static int disconnect_helper(struct transport *transport)
 226 {
 227         struct helper_data *data = transport->data;
 228         int res = 0;
 229
 230         if (data->helper) {
 231                 if (debug)
 232                         fprintf(stderr, "Debug: Disconnecting.\n");
 233                 if (!data->no_disconnect_req) {
 234                         /*
 235                          * Ignore write errors; there's nothing we can do,
 236                          * since we're about to close the pipe anyway. And the
 237                          * most likely error is EPIPE due to the helper dying
 238                          * to report an error itself.
 239                          */
 240                         sigchain_push(SIGPIPE, SIG_IGN);
 241                         xwrite(data->helper->in, "\n", 1);
 242                         sigchain_pop(SIGPIPE);
 243                 }
 244                 close(data->helper->in);
 245                 close(data->helper->out);
 246                 fclose(data->out);
 247                 res = finish_command(data->helper);
 248                 argv_array_free_detached(data->helper->argv);
 249                 free(data->helper);
 250                 data->helper = NULL;
 251         }
 252         return res;
 253 }
 254
 255 static const char *unsupported_options[] = {
 256         TRANS_OPT_UPLOADPACK,
 257         TRANS_OPT_RECEIVEPACK,
 258         TRANS_OPT_THIN,
 259         TRANS_OPT_KEEP
 260         };
 261
 262 static const char *boolean_options[] = {
 263         TRANS_OPT_THIN,
 264         TRANS_OPT_KEEP,
 265         TRANS_OPT_FOLLOWTAGS
 266         };
 267
 268 static int set_helper_option(struct transport *transport,
 269                           const char *name, const char *value)
 270 {
 271         struct helper_data *data = transport->data;
 272         struct strbuf buf = STRBUF_INIT;
 273         int i, ret, is_bool = 0;
 274
 275         get_helper(transport);
 276
 277         if (!data->option)
 278                 return 1;
 279
 280         for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 281                 if (!strcmp(name, unsupported_options[i]))
 282                         return 1;
 283         }
 284
 285         for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 286                 if (!strcmp(name, boolean_options[i])) {
 287                         is_bool = 1;
 288                         break;
 289                 }
 290         }
 291
 292         strbuf_addf(&buf, "option %s ", name);
 293         if (is_bool)
 294                 strbuf_addstr(&buf, value ? "true" : "false");
 295         else
 296                 quote_c_style(value, &buf, NULL, 0);
 297         strbuf_addch(&buf, '\n');
 298
 299         sendline(data, &buf);
 300         if (recvline(data, &buf))
 301                 exit(128);
 302
 303         if (!strcmp(buf.buf, "ok"))
 304                 ret = 0;
 305         else if (starts_with(buf.buf, "error")) {
 306                 ret = -1;
 307         } else if (!strcmp(buf.buf, "unsupported"))
 308                 ret = 1;
 309         else {
 310                 warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 311                 ret = 1;
 312         }
 313         strbuf_release(&buf);
 314         return ret;
 315 }
 316
 317 static void standard_options(struct transport *t)
 318 {
 319         char buf[16];
 320         int n;
 321         int v = t->verbose;
 322
 323         set_helper_option(t, "progress", t->progress ? "true" : "false");
 324
 325         n = snprintf(buf, sizeof(buf), "%d", v + 1);
 326         if (n >= sizeof(buf))
 327                 die("impossibly large verbosity value");
 328         set_helper_option(t, "verbosity", buf);
 329 }
 330
 331 static int release_helper(struct transport *transport)
 332 {
 333         int res = 0;
 334         struct helper_data *data = transport->data;
 335         free_refspec(data->refspec_nr, data->refspecs);
 336         data->refspecs = NULL;
 337         res = disconnect_helper(transport);
 338         free(transport->data);
 339         return res;
 340 }
 341
 342 static int fetch_with_fetch(struct transport *transport,
 343                             int nr_heads, struct ref **to_fetch)
 344 {
 345         struct helper_data *data = transport->data;
 346         int i;
 347         struct strbuf buf = STRBUF_INIT;
 348
 349         standard_options(transport);
 350         if (data->check_connectivity &&
 351             data->transport_options.check_self_contained_and_connected)
 352                 set_helper_option(transport, "check-connectivity", "true");
 353
 354         if (transport->cloning)
 355                 set_helper_option(transport, "cloning", "true");
 356
 357         if (data->transport_options.update_shallow)
 358                 set_helper_option(transport, "update-shallow", "true");
 359
 360         for (i = 0; i < nr_heads; i++) {
 361                 const struct ref *posn = to_fetch[i];
 362                 if (posn->status & REF_STATUS_UPTODATE)
 363                         continue;
 364
 365                 strbuf_addf(&buf, "fetch %s %s\n",
 366                             sha1_to_hex(posn->old_sha1), posn->name);
 367         }
 368
 369         strbuf_addch(&buf, '\n');
 370         sendline(data, &buf);
 371
 372         while (1) {
 373                 if (recvline(data, &buf))
 374                         exit(128);
 375
 376                 if (starts_with(buf.buf, "lock ")) {
 377                         const char *name = buf.buf + 5;
 378                         if (transport->pack_lockfile)
 379                                 warning("%s also locked %s", data->name, name);
 380                         else
 381                                 transport->pack_lockfile = xstrdup(name);
 382                 }
 383                 else if (data->check_connectivity &&
 384                          data->transport_options.check_self_contained_and_connected &&
 385                          !strcmp(buf.buf, "connectivity-ok"))
 386                         data->transport_options.self_contained_and_connected = 1;
 387                 else if (!buf.len)
 388                         break;
 389                 else
 390                         warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 391         }
 392         strbuf_release(&buf);
 393         return 0;
 394 }
 395
 396 static int get_importer(struct transport *transport, struct child_process *fastimport)
 397 {
 398         struct child_process *helper = get_helper(transport);
 399         struct helper_data *data = transport->data;
 400         struct argv_array argv = ARGV_ARRAY_INIT;
 401         int cat_blob_fd, code;
 402         memset(fastimport, 0, sizeof(*fastimport));
 403         fastimport->in = helper->out;
 404         argv_array_push(&argv, "fast-import");
 405         argv_array_push(&argv, debug ? "--stats" : "--quiet");
 406
 407         if (data->bidi_import) {
 408                 cat_blob_fd = xdup(helper->in);
 409                 argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 410         }
 411         fastimport->argv = argv.argv;
 412         fastimport->git_cmd = 1;
 413
 414         code = start_command(fastimport);
 415         return code;
 416 }
 417
 418 static int get_exporter(struct transport *transport,
 419                         struct child_process *fastexport,
 420                         struct string_list *revlist_args)
 421 {
 422         struct helper_data *data = transport->data;
 423         struct child_process *helper = get_helper(transport);
 424         int argc = 0, i;
 425         memset(fastexport, 0, sizeof(*fastexport));
 426         struct strbuf tmp = STRBUF_INIT;
 427
 428         /* we need to duplicate helper->in because we want to use it after
 429          * fastexport is done with it. */
 430         fastexport->out = dup(helper->in);
 431         fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
 432         fastexport->argv[argc++] = "fast-export";
 433         fastexport->argv[argc++] = "--use-done-feature";
 434         fastexport->argv[argc++] = data->signed_tags ?
 435                 "--signed-tags=verbatim" : "--signed-tags=warn-strip";
 436         if (data->export_marks) {
 437                 strbuf_addf(&tmp, "--export-marks=%s.tmp", data->export_marks);
 438                 fastexport->argv[argc++] = strbuf_detach(&tmp, NULL);
 439         }
 440         if (data->import_marks) {
 441                 strbuf_addf(&tmp, "--import-marks=%s", data->import_marks);
 442                 fastexport->argv[argc++] = strbuf_detach(&tmp, NULL);
 443         }
 444
 445         for (i = 0; i < revlist_args->nr; i++)
 446                 fastexport->argv[argc++] = revlist_args->items[i].string;
 447
 448         fastexport->git_cmd = 1;
 449         return start_command(fastexport);
 450 }
 451
 452 static int fetch_with_import(struct transport *transport,
 453                              int nr_heads, struct ref **to_fetch)
 454 {
 455         struct child_process fastimport;
 456         struct helper_data *data = transport->data;
 457         int i;
 458         struct ref *posn;
 459         struct strbuf buf = STRBUF_INIT;
 460
 461         get_helper(transport);
 462
 463         if (get_importer(transport, &fastimport))
 464                 die("Couldn't run fast-import");
 465
 466         for (i = 0; i < nr_heads; i++) {
 467                 posn = to_fetch[i];
 468                 if (posn->status & REF_STATUS_UPTODATE)
 469                         continue;
 470
 471                 strbuf_addf(&buf, "import %s\n", posn->name);
 472                 sendline(data, &buf);
 473                 strbuf_reset(&buf);
 474         }
 475
 476         write_constant(data->helper->in, "\n");
 477         /*
 478          * remote-helpers that advertise the bidi-import capability are required to
 479          * buffer the complete batch of import commands until this newline before
 480          * sending data to fast-import.
 481          * These helpers read back data from fast-import on their stdin, which could
 482          * be mixed with import commands, otherwise.
 483          */
 484
 485         if (finish_command(&fastimport))
 486                 die("Error while running fast-import");
 487         argv_array_free_detached(fastimport.argv);
 488
 489         /*
 490          * The fast-import stream of a remote helper that advertises
 491          * the "refspec" capability writes to the refs named after the
 492          * right hand side of the first refspec matching each ref we
 493          * were fetching.
 494          *
 495          * (If no "refspec" capability was specified, for historical
 496          * reasons we default to the equivalent of *:*.)
 497          *
 498          * Store the result in to_fetch[i].old_sha1.  Callers such
 499          * as "git fetch" can use the value to write feedback to the
 500          * terminal, populate FETCH_HEAD, and determine what new value
 501          * should be written to peer_ref if the update is a
 502          * fast-forward or this is a forced update.
 503          */
 504         for (i = 0; i < nr_heads; i++) {
 505                 char *private;
 506                 posn = to_fetch[i];
 507                 if (posn->status & REF_STATUS_UPTODATE)
 508                         continue;
 509                 if (data->refspecs)
 510                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 511                 else
 512                         private = xstrdup(posn->name);
 513                 if (private) {
 514                         read_ref(private, posn->old_sha1);
 515                         free(private);
 516                 }
 517         }
 518         strbuf_release(&buf);
 519         return 0;
 520 }
 521
 522 static int process_connect_service(struct transport *transport,
 523                                    const char *name, const char *exec)
 524 {
 525         struct helper_data *data = transport->data;
 526         struct strbuf cmdbuf = STRBUF_INIT;
 527         struct child_process *helper;
 528         int r, duped, ret = 0;
 529         FILE *input;
 530
 531         helper = get_helper(transport);
 532
 533         /*
 534          * Yes, dup the pipe another time, as we need unbuffered version
 535          * of input pipe as FILE*. fclose() closes the underlying fd and
 536          * stream buffering only can be changed before first I/O operation
 537          * on it.
 538          */
 539         duped = dup(helper->out);
 540         if (duped < 0)
 541                 die_errno("Can't dup helper output fd");
 542         input = xfdopen(duped, "r");
 543         setvbuf(input, NULL, _IONBF, 0);
 544
 545         /*
 546          * Handle --upload-pack and friends. This is fire and forget...
 547          * just warn if it fails.
 548          */
 549         if (strcmp(name, exec)) {
 550                 r = set_helper_option(transport, "servpath", exec);
 551                 if (r > 0)
 552                         warning("Setting remote service path not supported by protocol.");
 553                 else if (r < 0)
 554                         warning("Invalid remote service path.");
 555         }
 556
 557         if (data->connect)
 558                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 559         else
 560                 goto exit;
 561
 562         sendline(data, &cmdbuf);
 563         if (recvline_fh(input, &cmdbuf, name))
 564                 exit(128);
 565
 566         if (!strcmp(cmdbuf.buf, "")) {
 567                 data->no_disconnect_req = 1;
 568                 if (debug)
 569                         fprintf(stderr, "Debug: Smart transport connection "
 570                                 "ready.\n");
 571                 ret = 1;
 572         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 573                 if (debug)
 574                         fprintf(stderr, "Debug: Falling back to dumb "
 575                                 "transport.\n");
 576         } else
 577                 die("Unknown response to connect: %s",
 578                         cmdbuf.buf);
 579
 580 exit:
 581         fclose(input);
 582         return ret;
 583 }
 584
 585 static int process_connect(struct transport *transport,
 586                                      int for_push)
 587 {
 588         struct helper_data *data = transport->data;
 589         const char *name;
 590         const char *exec;
 591
 592         name = for_push ? "git-receive-pack" : "git-upload-pack";
 593         if (for_push)
 594                 exec = data->transport_options.receivepack;
 595         else
 596                 exec = data->transport_options.uploadpack;
 597
 598         return process_connect_service(transport, name, exec);
 599 }
 600
 601 static int connect_helper(struct transport *transport, const char *name,
 602                    const char *exec, int fd[2])
 603 {
 604         struct helper_data *data = transport->data;
 605
 606         /* Get_helper so connect is inited. */
 607         get_helper(transport);
 608         if (!data->connect)
 609                 die("Operation not supported by protocol.");
 610
 611         if (!process_connect_service(transport, name, exec))
 612                 die("Can't connect to subservice %s.", name);
 613
 614         fd[0] = data->helper->out;
 615         fd[1] = data->helper->in;
 616         return 0;
 617 }
 618
 619 static int fetch(struct transport *transport,
 620                  int nr_heads, struct ref **to_fetch)
 621 {
 622         struct helper_data *data = transport->data;
 623         int i, count;
 624
 625         if (process_connect(transport, 0)) {
 626                 do_take_over(transport);
 627                 return transport->fetch(transport, nr_heads, to_fetch);
 628         }
 629
 630         count = 0;
 631         for (i = 0; i < nr_heads; i++)
 632                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 633                         count++;
 634
 635         if (!count)
 636                 return 0;
 637
 638         if (data->fetch)
 639                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 640
 641         if (data->import)
 642                 return fetch_with_import(transport, nr_heads, to_fetch);
 643
 644         return -1;
 645 }
 646
 647 static int push_update_ref_status(struct strbuf *buf,
 648                                    struct ref **ref,
 649                                    struct ref *remote_refs)
 650 {
 651         char *refname, *msg;
 652         int status, forced = 0;
 653
 654         if (starts_with(buf->buf, "ok ")) {
 655                 status = REF_STATUS_OK;
 656                 refname = buf->buf + 3;
 657         } else if (starts_with(buf->buf, "error ")) {
 658                 status = REF_STATUS_REMOTE_REJECT;
 659                 refname = buf->buf + 6;
 660         } else
 661                 die("expected ok/error, helper said '%s'", buf->buf);
 662
 663         msg = strchr(refname, ' ');
 664         if (msg) {
 665                 struct strbuf msg_buf = STRBUF_INIT;
 666                 const char *end;
 667
 668                 *msg++ = '\0';
 669                 if (!unquote_c_style(&msg_buf, msg, &end))
 670                         msg = strbuf_detach(&msg_buf, NULL);
 671                 else
 672                         msg = xstrdup(msg);
 673                 strbuf_release(&msg_buf);
 674
 675                 if (!strcmp(msg, "no match")) {
 676                         status = REF_STATUS_NONE;
 677                         free(msg);
 678                         msg = NULL;
 679                 }
 680                 else if (!strcmp(msg, "up to date")) {
 681                         status = REF_STATUS_UPTODATE;
 682                         free(msg);
 683                         msg = NULL;
 684                 }
 685                 else if (!strcmp(msg, "non-fast forward")) {
 686                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 687                         free(msg);
 688                         msg = NULL;
 689                 }
 690                 else if (!strcmp(msg, "already exists")) {
 691                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 692                         free(msg);
 693                         msg = NULL;
 694                 }
 695                 else if (!strcmp(msg, "fetch first")) {
 696                         status = REF_STATUS_REJECT_FETCH_FIRST;
 697                         free(msg);
 698                         msg = NULL;
 699                 }
 700                 else if (!strcmp(msg, "needs force")) {
 701                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 702                         free(msg);
 703                         msg = NULL;
 704                 }
 705                 else if (!strcmp(msg, "stale info")) {
 706                         status = REF_STATUS_REJECT_STALE;
 707                         free(msg);
 708                         msg = NULL;
 709                 }
 710                 else if (!strcmp(msg, "forced update")) {
 711                         forced = 1;
 712                         free(msg);
 713                         msg = NULL;
 714                 }
 715         }
 716
 717         if (*ref)
 718                 *ref = find_ref_by_name(*ref, refname);
 719         if (!*ref)
 720                 *ref = find_ref_by_name(remote_refs, refname);
 721         if (!*ref) {
 722                 warning("helper reported unexpected status of %s", refname);
 723                 return 1;
 724         }
 725
 726         if ((*ref)->status != REF_STATUS_NONE) {
 727                 /*
 728                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 729                  * status reported by the remote helper if the latter is 'no match'.
 730                  */
 731                 if (status == REF_STATUS_NONE)
 732                         return 1;
 733         }
 734
 735         (*ref)->status = status;
 736         (*ref)->forced_update |= forced;
 737         (*ref)->remote_status = msg;
 738         return !(status == REF_STATUS_OK);
 739 }
 740
 741 static int push_update_refs_status(struct helper_data *data,
 742                                     struct ref *remote_refs,
 743                                     int flags)
 744 {
 745         struct strbuf buf = STRBUF_INIT;
 746         struct ref *ref = remote_refs;
 747         int ret = 0;
 748
 749         for (;;) {
 750                 char *private;
 751
 752                 if (recvline(data, &buf)) {
 753                         ret = 1;
 754                         break;
 755                 }
 756
 757                 if (!buf.len)
 758                         break;
 759
 760                 if (push_update_ref_status(&buf, &ref, remote_refs))
 761                         continue;
 762
 763                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 764                         continue;
 765
 766                 /* propagate back the update to the remote namespace */
 767                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 768                 if (!private)
 769                         continue;
 770                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 771                 free(private);
 772         }
 773         strbuf_release(&buf);
 774         return ret;
 775 }
 776
 777 static int push_refs_with_push(struct transport *transport,
 778                                struct ref *remote_refs, int flags)
 779 {
 780         int force_all = flags & TRANSPORT_PUSH_FORCE;
 781         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 782         struct helper_data *data = transport->data;
 783         struct strbuf buf = STRBUF_INIT;
 784         struct ref *ref;
 785         struct string_list cas_options = STRING_LIST_INIT_DUP;
 786         struct string_list_item *cas_option;
 787
 788         get_helper(transport);
 789         if (!data->push)
 790                 return 1;
 791
 792         for (ref = remote_refs; ref; ref = ref->next) {
 793                 if (!ref->peer_ref && !mirror)
 794                         continue;
 795
 796                 /* Check for statuses set by set_ref_status_for_push() */
 797                 switch (ref->status) {
 798                 case REF_STATUS_REJECT_NONFASTFORWARD:
 799                 case REF_STATUS_REJECT_STALE:
 800                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 801                 case REF_STATUS_UPTODATE:
 802                         continue;
 803                 default:
 804                         ; /* do nothing */
 805                 }
 806
 807                 if (force_all)
 808                         ref->force = 1;
 809
 810                 strbuf_addstr(&buf, "push ");
 811                 if (!ref->deletion) {
 812                         if (ref->force)
 813                                 strbuf_addch(&buf, '+');
 814                         if (ref->peer_ref)
 815                                 strbuf_addstr(&buf, ref->peer_ref->name);
 816                         else
 817                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 818                 }
 819                 strbuf_addch(&buf, ':');
 820                 strbuf_addstr(&buf, ref->name);
 821                 strbuf_addch(&buf, '\n');
 822
 823                 /*
 824                  * The "--force-with-lease" options without explicit
 825                  * values to expect have already been expanded into
 826                  * the ref->old_sha1_expect[] field; we can ignore
 827                  * transport->smart_options->cas altogether and instead
 828                  * can enumerate them from the refs.
 829                  */
 830                 if (ref->expect_old_sha1) {
 831                         struct strbuf cas = STRBUF_INIT;
 832                         strbuf_addf(&cas, "%s:%s",
 833                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 834                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 835                 }
 836         }
 837         if (buf.len == 0) {
 838                 string_list_clear(&cas_options, 0);
 839                 return 0;
 840         }
 841
 842         standard_options(transport);
 843         for_each_string_list_item(cas_option, &cas_options)
 844                 set_helper_option(transport, "cas", cas_option->string);
 845
 846         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 847                 if (set_helper_option(transport, "dry-run", "true") != 0)
 848                         die("helper %s does not support dry-run", data->name);
 849         }
 850
 851         strbuf_addch(&buf, '\n');
 852         sendline(data, &buf);
 853         strbuf_release(&buf);
 854
 855         return push_update_refs_status(data, remote_refs, flags);
 856 }
 857
 858 static int push_refs_with_export(struct transport *transport,
 859                 struct ref *remote_refs, int flags)
 860 {
 861         struct ref *ref;
 862         struct child_process *helper, exporter;
 863         struct helper_data *data = transport->data;
 864         struct string_list revlist_args = STRING_LIST_INIT_DUP;
 865         struct strbuf buf = STRBUF_INIT;
 866
 867         if (!data->refspecs)
 868                 die("remote-helper doesn't support push; refspec needed");
 869
 870         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 871                 if (set_helper_option(transport, "dry-run", "true") != 0)
 872                         die("helper %s does not support dry-run", data->name);
 873         }
 874
 875         if (flags & TRANSPORT_PUSH_FORCE) {
 876                 if (set_helper_option(transport, "force", "true") != 0)
 877                         warning("helper %s does not support 'force'", data->name);
 878         }
 879
 880         helper = get_helper(transport);
 881
 882         write_constant(helper->in, "export\n");
 883
 884         for (ref = remote_refs; ref; ref = ref->next) {
 885                 char *private;
 886                 unsigned char sha1[20];
 887
 888                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 889                 if (private && !get_sha1(private, sha1)) {
 890                         strbuf_addf(&buf, "^%s", private);
 891                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 892                         hashcpy(ref->old_sha1, sha1);
 893                 }
 894                 free(private);
 895
 896                 if (ref->peer_ref) {
 897                         if (strcmp(ref->name, ref->peer_ref->name)) {
 898                                 if (!ref->deletion) {
 899                                         const char *name;
 900                                         int flag;
 901
 902                                         /* Follow symbolic refs (mainly for HEAD). */
 903                                         name = resolve_ref_unsafe(ref->peer_ref->name, sha1, 1, &flag);
 904                                         if (!name || !(flag & REF_ISSYMREF))
 905                                                 name = ref->peer_ref->name;
 906
 907                                         strbuf_addf(&buf, "%s:%s", name, ref->name);
 908                                 } else
 909                                         strbuf_addf(&buf, ":%s", ref->name);
 910
 911                                 string_list_append(&revlist_args, "--refspec");
 912                                 string_list_append(&revlist_args, buf.buf);
 913                                 strbuf_release(&buf);
 914                         }
 915                         if (!ref->deletion)
 916                                 string_list_append(&revlist_args, ref->peer_ref->name);
 917                 }
 918         }
 919
 920         if (get_exporter(transport, &exporter, &revlist_args))
 921                 die("Couldn't run fast-export");
 922
 923         string_list_clear(&revlist_args, 1);
 924
 925         if (finish_command(&exporter))
 926                 die("Error while running fast-export");
 927         if (push_update_refs_status(data, remote_refs, flags))
 928                 return 1;
 929
 930         if (data->export_marks) {
 931                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 932                 rename(buf.buf, data->export_marks);
 933                 strbuf_release(&buf);
 934         }
 935
 936         return 0;
 937 }
 938
 939 static int push_refs(struct transport *transport,
 940                 struct ref *remote_refs, int flags)
 941 {
 942         struct helper_data *data = transport->data;
 943
 944         if (process_connect(transport, 1)) {
 945                 do_take_over(transport);
 946                 return transport->push_refs(transport, remote_refs, flags);
 947         }
 948
 949         if (!remote_refs) {
 950                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 951                         "Perhaps you should specify a branch such as 'master'.\n");
 952                 return 0;
 953         }
 954
 955         if (data->push)
 956                 return push_refs_with_push(transport, remote_refs, flags);
 957
 958         if (data->export)
 959                 return push_refs_with_export(transport, remote_refs, flags);
 960
 961         return -1;
 962 }
 963
 964
 965 static int has_attribute(const char *attrs, const char *attr) {
 966         int len;
 967         if (!attrs)
 968                 return 0;
 969
 970         len = strlen(attr);
 971         for (;;) {
 972                 const char *space = strchrnul(attrs, ' ');
 973                 if (len == space - attrs && !strncmp(attrs, attr, len))
 974                         return 1;
 975                 if (!*space)
 976                         return 0;
 977                 attrs = space + 1;
 978         }
 979 }
 980
 981 static struct ref *get_refs_list(struct transport *transport, int for_push)
 982 {
 983         struct helper_data *data = transport->data;
 984         struct child_process *helper;
 985         struct ref *ret = NULL;
 986         struct ref **tail = &ret;
 987         struct ref *posn;
 988         struct strbuf buf = STRBUF_INIT;
 989
 990         helper = get_helper(transport);
 991
 992         if (process_connect(transport, for_push)) {
 993                 do_take_over(transport);
 994                 return transport->get_refs_list(transport, for_push);
 995         }
 996
 997         if (data->push && for_push)
 998                 write_str_in_full(helper->in, "list for-push\n");
 999         else
1000                 write_str_in_full(helper->in, "list\n");
1001
1002         while (1) {
1003                 char *eov, *eon;
1004                 if (recvline(data, &buf))
1005                         exit(128);
1006
1007                 if (!*buf.buf)
1008                         break;
1009
1010                 eov = strchr(buf.buf, ' ');
1011                 if (!eov)
1012                         die("Malformed response in ref list: %s", buf.buf);
1013                 eon = strchr(eov + 1, ' ');
1014                 *eov = '\0';
1015                 if (eon)
1016                         *eon = '\0';
1017                 *tail = alloc_ref(eov + 1);
1018                 if (buf.buf[0] == '@')
1019                         (*tail)->symref = xstrdup(buf.buf + 1);
1020                 else if (buf.buf[0] != '?')
1021                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1022                 if (eon) {
1023                         if (has_attribute(eon + 1, "unchanged")) {
1024                                 (*tail)->status |= REF_STATUS_UPTODATE;
1025                                 read_ref((*tail)->name, (*tail)->old_sha1);
1026                         }
1027                 }
1028                 tail = &((*tail)->next);
1029         }
1030         if (debug)
1031                 fprintf(stderr, "Debug: Read ref listing.\n");
1032         strbuf_release(&buf);
1033
1034         for (posn = ret; posn; posn = posn->next)
1035                 resolve_remote_symref(posn, ret);
1036
1037         return ret;
1038 }
1039
1040 int transport_helper_init(struct transport *transport, const char *name)
1041 {
1042         struct helper_data *data = xcalloc(sizeof(*data), 1);
1043         data->name = name;
1044
1045         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1046                 debug = 1;
1047
1048         transport->data = data;
1049         transport->set_option = set_helper_option;
1050         transport->get_refs_list = get_refs_list;
1051         transport->fetch = fetch;
1052         transport->push_refs = push_refs;
1053         transport->disconnect = release_helper;
1054         transport->connect = connect_helper;
1055         transport->smart_options = &(data->transport_options);
1056         return 0;
1057 }
1058
1059 /*
1060  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1061  * buffer less), so attempt reads and writes with up to that size.
1062  */
1063 #define BUFFERSIZE 65536
1064 /* This should be enough to hold debugging message. */
1065 #define PBUFFERSIZE 8192
1066
1067 /* Print bidirectional transfer loop debug message. */
1068 __attribute__((format (printf, 1, 2)))
1069 static void transfer_debug(const char *fmt, ...)
1070 {
1071         va_list args;
1072         char msgbuf[PBUFFERSIZE];
1073         static int debug_enabled = -1;
1074
1075         if (debug_enabled < 0)
1076                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1077         if (!debug_enabled)
1078                 return;
1079
1080         va_start(args, fmt);
1081         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1082         va_end(args);
1083         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1084 }
1085
1086 /* Stream state: More data may be coming in this direction. */
1087 #define SSTATE_TRANSFERING 0
1088 /*
1089  * Stream state: No more data coming in this direction, flushing rest of
1090  * data.
1091  */
1092 #define SSTATE_FLUSHING 1
1093 /* Stream state: Transfer in this direction finished. */
1094 #define SSTATE_FINISHED 2
1095
1096 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1097 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1098 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1099
1100 /* Unidirectional transfer. */
1101 struct unidirectional_transfer {
1102         /* Source */
1103         int src;
1104         /* Destination */
1105         int dest;
1106         /* Is source socket? */
1107         int src_is_sock;
1108         /* Is destination socket? */
1109         int dest_is_sock;
1110         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1111         int state;
1112         /* Buffer. */
1113         char buf[BUFFERSIZE];
1114         /* Buffer used. */
1115         size_t bufuse;
1116         /* Name of source. */
1117         const char *src_name;
1118         /* Name of destination. */
1119         const char *dest_name;
1120 };
1121
1122 /* Closes the target (for writing) if transfer has finished. */
1123 static void udt_close_if_finished(struct unidirectional_transfer *t)
1124 {
1125         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1126                 t->state = SSTATE_FINISHED;
1127                 if (t->dest_is_sock)
1128                         shutdown(t->dest, SHUT_WR);
1129                 else
1130                         close(t->dest);
1131                 transfer_debug("Closed %s.", t->dest_name);
1132         }
1133 }
1134
1135 /*
1136  * Tries to read read data from source into buffer. If buffer is full,
1137  * no data is read. Returns 0 on success, -1 on error.
1138  */
1139 static int udt_do_read(struct unidirectional_transfer *t)
1140 {
1141         ssize_t bytes;
1142
1143         if (t->bufuse == BUFFERSIZE)
1144                 return 0;       /* No space for more. */
1145
1146         transfer_debug("%s is readable", t->src_name);
1147         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1148         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1149                 errno != EINTR) {
1150                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1151                 return -1;
1152         } else if (bytes == 0) {
1153                 transfer_debug("%s EOF (with %i bytes in buffer)",
1154                         t->src_name, (int)t->bufuse);
1155                 t->state = SSTATE_FLUSHING;
1156         } else if (bytes > 0) {
1157                 t->bufuse += bytes;
1158                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1159                         (int)bytes, t->src_name, (int)t->bufuse);
1160         }
1161         return 0;
1162 }
1163
1164 /* Tries to write data from buffer into destination. If buffer is empty,
1165  * no data is written. Returns 0 on success, -1 on error.
1166  */
1167 static int udt_do_write(struct unidirectional_transfer *t)
1168 {
1169         ssize_t bytes;
1170
1171         if (t->bufuse == 0)
1172                 return 0;       /* Nothing to write. */
1173
1174         transfer_debug("%s is writable", t->dest_name);
1175         bytes = xwrite(t->dest, t->buf, t->bufuse);
1176         if (bytes < 0 && errno != EWOULDBLOCK) {
1177                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1178                 return -1;
1179         } else if (bytes > 0) {
1180                 t->bufuse -= bytes;
1181                 if (t->bufuse)
1182                         memmove(t->buf, t->buf + bytes, t->bufuse);
1183                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1184                         (int)bytes, t->dest_name, (int)t->bufuse);
1185         }
1186         return 0;
1187 }
1188
1189
1190 /* State of bidirectional transfer loop. */
1191 struct bidirectional_transfer_state {
1192         /* Direction from program to git. */
1193         struct unidirectional_transfer ptg;
1194         /* Direction from git to program. */
1195         struct unidirectional_transfer gtp;
1196 };
1197
1198 static void *udt_copy_task_routine(void *udt)
1199 {
1200         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1201         while (t->state != SSTATE_FINISHED) {
1202                 if (STATE_NEEDS_READING(t->state))
1203                         if (udt_do_read(t))
1204                                 return NULL;
1205                 if (STATE_NEEDS_WRITING(t->state))
1206                         if (udt_do_write(t))
1207                                 return NULL;
1208                 if (STATE_NEEDS_CLOSING(t->state))
1209                         udt_close_if_finished(t);
1210         }
1211         return udt;     /* Just some non-NULL value. */
1212 }
1213
1214 #ifndef NO_PTHREADS
1215
1216 /*
1217  * Join thread, with appropriate errors on failure. Name is name for the
1218  * thread (for error messages). Returns 0 on success, 1 on failure.
1219  */
1220 static int tloop_join(pthread_t thread, const char *name)
1221 {
1222         int err;
1223         void *tret;
1224         err = pthread_join(thread, &tret);
1225         if (!tret) {
1226                 error("%s thread failed", name);
1227                 return 1;
1228         }
1229         if (err) {
1230                 error("%s thread failed to join: %s", name, strerror(err));
1231                 return 1;
1232         }
1233         return 0;
1234 }
1235
1236 /*
1237  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1238  * -1 on failure.
1239  */
1240 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1241 {
1242         pthread_t gtp_thread;
1243         pthread_t ptg_thread;
1244         int err;
1245         int ret = 0;
1246         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1247                 &s->gtp);
1248         if (err)
1249                 die("Can't start thread for copying data: %s", strerror(err));
1250         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1251                 &s->ptg);
1252         if (err)
1253                 die("Can't start thread for copying data: %s", strerror(err));
1254
1255         ret |= tloop_join(gtp_thread, "Git to program copy");
1256         ret |= tloop_join(ptg_thread, "Program to git copy");
1257         return ret;
1258 }
1259 #else
1260
1261 /* Close the source and target (for writing) for transfer. */
1262 static void udt_kill_transfer(struct unidirectional_transfer *t)
1263 {
1264         t->state = SSTATE_FINISHED;
1265         /*
1266          * Socket read end left open isn't a disaster if nobody
1267          * attempts to read from it (mingw compat headers do not
1268          * have SHUT_RD)...
1269          *
1270          * We can't fully close the socket since otherwise gtp
1271          * task would first close the socket it sends data to
1272          * while closing the ptg file descriptors.
1273          */
1274         if (!t->src_is_sock)
1275                 close(t->src);
1276         if (t->dest_is_sock)
1277                 shutdown(t->dest, SHUT_WR);
1278         else
1279                 close(t->dest);
1280 }
1281
1282 /*
1283  * Join process, with appropriate errors on failure. Name is name for the
1284  * process (for error messages). Returns 0 on success, 1 on failure.
1285  */
1286 static int tloop_join(pid_t pid, const char *name)
1287 {
1288         int tret;
1289         if (waitpid(pid, &tret, 0) < 0) {
1290                 error("%s process failed to wait: %s", name, strerror(errno));
1291                 return 1;
1292         }
1293         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1294                 error("%s process failed", name);
1295                 return 1;
1296         }
1297         return 0;
1298 }
1299
1300 /*
1301  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1302  * -1 on failure.
1303  */
1304 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1305 {
1306         pid_t pid1, pid2;
1307         int ret = 0;
1308
1309         /* Fork thread #1: git to program. */
1310         pid1 = fork();
1311         if (pid1 < 0)
1312                 die_errno("Can't start thread for copying data");
1313         else if (pid1 == 0) {
1314                 udt_kill_transfer(&s->ptg);
1315                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1316         }
1317
1318         /* Fork thread #2: program to git. */
1319         pid2 = fork();
1320         if (pid2 < 0)
1321                 die_errno("Can't start thread for copying data");
1322         else if (pid2 == 0) {
1323                 udt_kill_transfer(&s->gtp);
1324                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1325         }
1326
1327         /*
1328          * Close both streams in parent as to not interfere with
1329          * end of file detection and wait for both tasks to finish.
1330          */
1331         udt_kill_transfer(&s->gtp);
1332         udt_kill_transfer(&s->ptg);
1333         ret |= tloop_join(pid1, "Git to program copy");
1334         ret |= tloop_join(pid2, "Program to git copy");
1335         return ret;
1336 }
1337 #endif
1338
1339 /*
1340  * Copies data from stdin to output and from input to stdout simultaneously.
1341  * Additionally filtering through given filter. If filter is NULL, uses
1342  * identity filter.
1343  */
1344 int bidirectional_transfer_loop(int input, int output)
1345 {
1346         struct bidirectional_transfer_state state;
1347
1348         /* Fill the state fields. */
1349         state.ptg.src = input;
1350         state.ptg.dest = 1;
1351         state.ptg.src_is_sock = (input == output);
1352         state.ptg.dest_is_sock = 0;
1353         state.ptg.state = SSTATE_TRANSFERING;
1354         state.ptg.bufuse = 0;
1355         state.ptg.src_name = "remote input";
1356         state.ptg.dest_name = "stdout";
1357
1358         state.gtp.src = 0;
1359         state.gtp.dest = output;
1360         state.gtp.src_is_sock = 0;
1361         state.gtp.dest_is_sock = (input == output);
1362         state.gtp.state = SSTATE_TRANSFERING;
1363         state.gtp.bufuse = 0;
1364         state.gtp.src_name = "stdin";
1365         state.gtp.dest_name = "remote output";
1366
1367         return tloop_spawnwait_tasks(&state);
1368 }