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         struct strbuf tmp = STRBUF_INIT;
 426
 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                 strbuf_addf(&tmp, "--export-marks=%s.tmp", data->export_marks);
 439                 fastexport->argv[argc++] = strbuf_detach(&tmp, NULL);
 440         }
 441         if (data->import_marks) {
 442                 strbuf_addf(&tmp, "--import-marks=%s", data->import_marks);
 443                 fastexport->argv[argc++] = strbuf_detach(&tmp, NULL);
 444         }
 445
 446         for (i = 0; i < revlist_args->nr; i++)
 447                 fastexport->argv[argc++] = revlist_args->items[i].string;
 448
 449         fastexport->git_cmd = 1;
 450         return start_command(fastexport);
 451 }
 452
 453 static int fetch_with_import(struct transport *transport,
 454                              int nr_heads, struct ref **to_fetch)
 455 {
 456         struct child_process fastimport;
 457         struct helper_data *data = transport->data;
 458         int i;
 459         struct ref *posn;
 460         struct strbuf buf = STRBUF_INIT;
 461
 462         get_helper(transport);
 463
 464         if (get_importer(transport, &fastimport))
 465                 die("Couldn't run fast-import");
 466
 467         for (i = 0; i < nr_heads; i++) {
 468                 posn = to_fetch[i];
 469                 if (posn->status & REF_STATUS_UPTODATE)
 470                         continue;
 471
 472                 strbuf_addf(&buf, "import %s\n", posn->name);
 473                 sendline(data, &buf);
 474                 strbuf_reset(&buf);
 475         }
 476
 477         write_constant(data->helper->in, "\n");
 478         /*
 479          * remote-helpers that advertise the bidi-import capability are required to
 480          * buffer the complete batch of import commands until this newline before
 481          * sending data to fast-import.
 482          * These helpers read back data from fast-import on their stdin, which could
 483          * be mixed with import commands, otherwise.
 484          */
 485
 486         if (finish_command(&fastimport))
 487                 die("Error while running fast-import");
 488         argv_array_free_detached(fastimport.argv);
 489
 490         /*
 491          * The fast-import stream of a remote helper that advertises
 492          * the "refspec" capability writes to the refs named after the
 493          * right hand side of the first refspec matching each ref we
 494          * were fetching.
 495          *
 496          * (If no "refspec" capability was specified, for historical
 497          * reasons we default to the equivalent of *:*.)
 498          *
 499          * Store the result in to_fetch[i].old_sha1.  Callers such
 500          * as "git fetch" can use the value to write feedback to the
 501          * terminal, populate FETCH_HEAD, and determine what new value
 502          * should be written to peer_ref if the update is a
 503          * fast-forward or this is a forced update.
 504          */
 505         for (i = 0; i < nr_heads; i++) {
 506                 char *private;
 507                 posn = to_fetch[i];
 508                 if (posn->status & REF_STATUS_UPTODATE)
 509                         continue;
 510                 if (data->refspecs)
 511                         private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 512                 else
 513                         private = xstrdup(posn->name);
 514                 if (private) {
 515                         read_ref(private, posn->old_sha1);
 516                         free(private);
 517                 }
 518         }
 519         strbuf_release(&buf);
 520         return 0;
 521 }
 522
 523 static int process_connect_service(struct transport *transport,
 524                                    const char *name, const char *exec)
 525 {
 526         struct helper_data *data = transport->data;
 527         struct strbuf cmdbuf = STRBUF_INIT;
 528         struct child_process *helper;
 529         int r, duped, ret = 0;
 530         FILE *input;
 531
 532         helper = get_helper(transport);
 533
 534         /*
 535          * Yes, dup the pipe another time, as we need unbuffered version
 536          * of input pipe as FILE*. fclose() closes the underlying fd and
 537          * stream buffering only can be changed before first I/O operation
 538          * on it.
 539          */
 540         duped = dup(helper->out);
 541         if (duped < 0)
 542                 die_errno("Can't dup helper output fd");
 543         input = xfdopen(duped, "r");
 544         setvbuf(input, NULL, _IONBF, 0);
 545
 546         /*
 547          * Handle --upload-pack and friends. This is fire and forget...
 548          * just warn if it fails.
 549          */
 550         if (strcmp(name, exec)) {
 551                 r = set_helper_option(transport, "servpath", exec);
 552                 if (r > 0)
 553                         warning("Setting remote service path not supported by protocol.");
 554                 else if (r < 0)
 555                         warning("Invalid remote service path.");
 556         }
 557
 558         if (data->connect)
 559                 strbuf_addf(&cmdbuf, "connect %s\n", name);
 560         else
 561                 goto exit;
 562
 563         sendline(data, &cmdbuf);
 564         if (recvline_fh(input, &cmdbuf, name))
 565                 exit(128);
 566
 567         if (!strcmp(cmdbuf.buf, "")) {
 568                 data->no_disconnect_req = 1;
 569                 if (debug)
 570                         fprintf(stderr, "Debug: Smart transport connection "
 571                                 "ready.\n");
 572                 ret = 1;
 573         } else if (!strcmp(cmdbuf.buf, "fallback")) {
 574                 if (debug)
 575                         fprintf(stderr, "Debug: Falling back to dumb "
 576                                 "transport.\n");
 577         } else
 578                 die("Unknown response to connect: %s",
 579                         cmdbuf.buf);
 580
 581 exit:
 582         fclose(input);
 583         return ret;
 584 }
 585
 586 static int process_connect(struct transport *transport,
 587                                      int for_push)
 588 {
 589         struct helper_data *data = transport->data;
 590         const char *name;
 591         const char *exec;
 592
 593         name = for_push ? "git-receive-pack" : "git-upload-pack";
 594         if (for_push)
 595                 exec = data->transport_options.receivepack;
 596         else
 597                 exec = data->transport_options.uploadpack;
 598
 599         return process_connect_service(transport, name, exec);
 600 }
 601
 602 static int connect_helper(struct transport *transport, const char *name,
 603                    const char *exec, int fd[2])
 604 {
 605         struct helper_data *data = transport->data;
 606
 607         /* Get_helper so connect is inited. */
 608         get_helper(transport);
 609         if (!data->connect)
 610                 die("Operation not supported by protocol.");
 611
 612         if (!process_connect_service(transport, name, exec))
 613                 die("Can't connect to subservice %s.", name);
 614
 615         fd[0] = data->helper->out;
 616         fd[1] = data->helper->in;
 617         return 0;
 618 }
 619
 620 static int fetch(struct transport *transport,
 621                  int nr_heads, struct ref **to_fetch)
 622 {
 623         struct helper_data *data = transport->data;
 624         int i, count;
 625
 626         if (process_connect(transport, 0)) {
 627                 do_take_over(transport);
 628                 return transport->fetch(transport, nr_heads, to_fetch);
 629         }
 630
 631         count = 0;
 632         for (i = 0; i < nr_heads; i++)
 633                 if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 634                         count++;
 635
 636         if (!count)
 637                 return 0;
 638
 639         if (data->fetch)
 640                 return fetch_with_fetch(transport, nr_heads, to_fetch);
 641
 642         if (data->import)
 643                 return fetch_with_import(transport, nr_heads, to_fetch);
 644
 645         return -1;
 646 }
 647
 648 static int push_update_ref_status(struct strbuf *buf,
 649                                    struct ref **ref,
 650                                    struct ref *remote_refs)
 651 {
 652         char *refname, *msg;
 653         int status, forced = 0;
 654
 655         if (starts_with(buf->buf, "ok ")) {
 656                 status = REF_STATUS_OK;
 657                 refname = buf->buf + 3;
 658         } else if (starts_with(buf->buf, "error ")) {
 659                 status = REF_STATUS_REMOTE_REJECT;
 660                 refname = buf->buf + 6;
 661         } else
 662                 die("expected ok/error, helper said '%s'", buf->buf);
 663
 664         msg = strchr(refname, ' ');
 665         if (msg) {
 666                 struct strbuf msg_buf = STRBUF_INIT;
 667                 const char *end;
 668
 669                 *msg++ = '\0';
 670                 if (!unquote_c_style(&msg_buf, msg, &end))
 671                         msg = strbuf_detach(&msg_buf, NULL);
 672                 else
 673                         msg = xstrdup(msg);
 674                 strbuf_release(&msg_buf);
 675
 676                 if (!strcmp(msg, "no match")) {
 677                         status = REF_STATUS_NONE;
 678                         free(msg);
 679                         msg = NULL;
 680                 }
 681                 else if (!strcmp(msg, "up to date")) {
 682                         status = REF_STATUS_UPTODATE;
 683                         free(msg);
 684                         msg = NULL;
 685                 }
 686                 else if (!strcmp(msg, "non-fast forward")) {
 687                         status = REF_STATUS_REJECT_NONFASTFORWARD;
 688                         free(msg);
 689                         msg = NULL;
 690                 }
 691                 else if (!strcmp(msg, "already exists")) {
 692                         status = REF_STATUS_REJECT_ALREADY_EXISTS;
 693                         free(msg);
 694                         msg = NULL;
 695                 }
 696                 else if (!strcmp(msg, "fetch first")) {
 697                         status = REF_STATUS_REJECT_FETCH_FIRST;
 698                         free(msg);
 699                         msg = NULL;
 700                 }
 701                 else if (!strcmp(msg, "needs force")) {
 702                         status = REF_STATUS_REJECT_NEEDS_FORCE;
 703                         free(msg);
 704                         msg = NULL;
 705                 }
 706                 else if (!strcmp(msg, "stale info")) {
 707                         status = REF_STATUS_REJECT_STALE;
 708                         free(msg);
 709                         msg = NULL;
 710                 }
 711                 else if (!strcmp(msg, "forced update")) {
 712                         forced = 1;
 713                         free(msg);
 714                         msg = NULL;
 715                 }
 716         }
 717
 718         if (*ref)
 719                 *ref = find_ref_by_name(*ref, refname);
 720         if (!*ref)
 721                 *ref = find_ref_by_name(remote_refs, refname);
 722         if (!*ref) {
 723                 warning("helper reported unexpected status of %s", refname);
 724                 return 1;
 725         }
 726
 727         if ((*ref)->status != REF_STATUS_NONE) {
 728                 /*
 729                  * Earlier, the ref was marked not to be pushed, so ignore the ref
 730                  * status reported by the remote helper if the latter is 'no match'.
 731                  */
 732                 if (status == REF_STATUS_NONE)
 733                         return 1;
 734         }
 735
 736         (*ref)->status = status;
 737         (*ref)->forced_update |= forced;
 738         (*ref)->remote_status = msg;
 739         return !(status == REF_STATUS_OK);
 740 }
 741
 742 static int push_update_refs_status(struct helper_data *data,
 743                                     struct ref *remote_refs,
 744                                     int flags)
 745 {
 746         struct strbuf buf = STRBUF_INIT;
 747         struct ref *ref = remote_refs;
 748         int ret = 0;
 749
 750         for (;;) {
 751                 char *private;
 752
 753                 if (recvline(data, &buf)) {
 754                         ret = 1;
 755                         break;
 756                 }
 757
 758                 if (!buf.len)
 759                         break;
 760
 761                 if (push_update_ref_status(&buf, &ref, remote_refs))
 762                         continue;
 763
 764                 if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 765                         continue;
 766
 767                 /* propagate back the update to the remote namespace */
 768                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 769                 if (!private)
 770                         continue;
 771                 update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 772                 free(private);
 773         }
 774         strbuf_release(&buf);
 775         return ret;
 776 }
 777
 778 static int push_refs_with_push(struct transport *transport,
 779                                struct ref *remote_refs, int flags)
 780 {
 781         int force_all = flags & TRANSPORT_PUSH_FORCE;
 782         int mirror = flags & TRANSPORT_PUSH_MIRROR;
 783         struct helper_data *data = transport->data;
 784         struct strbuf buf = STRBUF_INIT;
 785         struct ref *ref;
 786         struct string_list cas_options = STRING_LIST_INIT_DUP;
 787         struct string_list_item *cas_option;
 788
 789         get_helper(transport);
 790         if (!data->push)
 791                 return 1;
 792
 793         for (ref = remote_refs; ref; ref = ref->next) {
 794                 if (!ref->peer_ref && !mirror)
 795                         continue;
 796
 797                 /* Check for statuses set by set_ref_status_for_push() */
 798                 switch (ref->status) {
 799                 case REF_STATUS_REJECT_NONFASTFORWARD:
 800                 case REF_STATUS_REJECT_STALE:
 801                 case REF_STATUS_REJECT_ALREADY_EXISTS:
 802                 case REF_STATUS_UPTODATE:
 803                         continue;
 804                 default:
 805                         ; /* do nothing */
 806                 }
 807
 808                 if (force_all)
 809                         ref->force = 1;
 810
 811                 strbuf_addstr(&buf, "push ");
 812                 if (!ref->deletion) {
 813                         if (ref->force)
 814                                 strbuf_addch(&buf, '+');
 815                         if (ref->peer_ref)
 816                                 strbuf_addstr(&buf, ref->peer_ref->name);
 817                         else
 818                                 strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 819                 }
 820                 strbuf_addch(&buf, ':');
 821                 strbuf_addstr(&buf, ref->name);
 822                 strbuf_addch(&buf, '\n');
 823
 824                 /*
 825                  * The "--force-with-lease" options without explicit
 826                  * values to expect have already been expanded into
 827                  * the ref->old_sha1_expect[] field; we can ignore
 828                  * transport->smart_options->cas altogether and instead
 829                  * can enumerate them from the refs.
 830                  */
 831                 if (ref->expect_old_sha1) {
 832                         struct strbuf cas = STRBUF_INIT;
 833                         strbuf_addf(&cas, "%s:%s",
 834                                     ref->name, sha1_to_hex(ref->old_sha1_expect));
 835                         string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 836                 }
 837         }
 838         if (buf.len == 0) {
 839                 string_list_clear(&cas_options, 0);
 840                 return 0;
 841         }
 842
 843         standard_options(transport);
 844         for_each_string_list_item(cas_option, &cas_options)
 845                 set_helper_option(transport, "cas", cas_option->string);
 846
 847         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 848                 if (set_helper_option(transport, "dry-run", "true") != 0)
 849                         die("helper %s does not support dry-run", data->name);
 850         }
 851
 852         strbuf_addch(&buf, '\n');
 853         sendline(data, &buf);
 854         strbuf_release(&buf);
 855
 856         return push_update_refs_status(data, remote_refs, flags);
 857 }
 858
 859 static int push_refs_with_export(struct transport *transport,
 860                 struct ref *remote_refs, int flags)
 861 {
 862         struct ref *ref;
 863         struct child_process *helper, exporter;
 864         struct helper_data *data = transport->data;
 865         struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 866         struct strbuf buf = STRBUF_INIT;
 867
 868         if (!data->refspecs)
 869                 die("remote-helper doesn't support push; refspec needed");
 870
 871         if (flags & TRANSPORT_PUSH_DRY_RUN) {
 872                 if (set_helper_option(transport, "dry-run", "true") != 0)
 873                         die("helper %s does not support dry-run", data->name);
 874         }
 875
 876         if (flags & TRANSPORT_PUSH_FORCE) {
 877                 if (set_helper_option(transport, "force", "true") != 0)
 878                         warning("helper %s does not support 'force'", data->name);
 879         }
 880
 881         helper = get_helper(transport);
 882
 883         write_constant(helper->in, "export\n");
 884
 885         strbuf_reset(&buf);
 886
 887         for (ref = remote_refs; ref; ref = ref->next) {
 888                 char *private;
 889                 unsigned char sha1[20];
 890
 891                 if (ref->deletion)
 892                         die("remote-helpers do not support ref deletion");
 893
 894                 private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 895                 if (private && !get_sha1(private, sha1)) {
 896                         strbuf_addf(&buf, "^%s", private);
 897                         string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 898                         hashcpy(ref->old_sha1, sha1);
 899                 }
 900                 free(private);
 901
 902                 if (ref->peer_ref) {
 903                         if (strcmp(ref->peer_ref->name, ref->name))
 904                                 die("remote-helpers do not support old:new syntax");
 905                         string_list_append(&revlist_args, ref->peer_ref->name);
 906                 }
 907         }
 908
 909         if (get_exporter(transport, &exporter, &revlist_args))
 910                 die("Couldn't run fast-export");
 911
 912         if (finish_command(&exporter))
 913                 die("Error while running fast-export");
 914         if (push_update_refs_status(data, remote_refs, flags))
 915                 return 1;
 916
 917         if (data->export_marks) {
 918                 strbuf_addf(&buf, "%s.tmp", data->export_marks);
 919                 rename(buf.buf, data->export_marks);
 920                 strbuf_release(&buf);
 921         }
 922
 923         return 0;
 924 }
 925
 926 static int push_refs(struct transport *transport,
 927                 struct ref *remote_refs, int flags)
 928 {
 929         struct helper_data *data = transport->data;
 930
 931         if (process_connect(transport, 1)) {
 932                 do_take_over(transport);
 933                 return transport->push_refs(transport, remote_refs, flags);
 934         }
 935
 936         if (!remote_refs) {
 937                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 938                         "Perhaps you should specify a branch such as 'master'.\n");
 939                 return 0;
 940         }
 941
 942         if (data->push)
 943                 return push_refs_with_push(transport, remote_refs, flags);
 944
 945         if (data->export)
 946                 return push_refs_with_export(transport, remote_refs, flags);
 947
 948         return -1;
 949 }
 950
 951
 952 static int has_attribute(const char *attrs, const char *attr) {
 953         int len;
 954         if (!attrs)
 955                 return 0;
 956
 957         len = strlen(attr);
 958         for (;;) {
 959                 const char *space = strchrnul(attrs, ' ');
 960                 if (len == space - attrs && !strncmp(attrs, attr, len))
 961                         return 1;
 962                 if (!*space)
 963                         return 0;
 964                 attrs = space + 1;
 965         }
 966 }
 967
 968 static struct ref *get_refs_list(struct transport *transport, int for_push)
 969 {
 970         struct helper_data *data = transport->data;
 971         struct child_process *helper;
 972         struct ref *ret = NULL;
 973         struct ref **tail = &ret;
 974         struct ref *posn;
 975         struct strbuf buf = STRBUF_INIT;
 976
 977         helper = get_helper(transport);
 978
 979         if (process_connect(transport, for_push)) {
 980                 do_take_over(transport);
 981                 return transport->get_refs_list(transport, for_push);
 982         }
 983
 984         if (data->push && for_push)
 985                 write_str_in_full(helper->in, "list for-push\n");
 986         else
 987                 write_str_in_full(helper->in, "list\n");
 988
 989         while (1) {
 990                 char *eov, *eon;
 991                 if (recvline(data, &buf))
 992                         exit(128);
 993
 994                 if (!*buf.buf)
 995                         break;
 996
 997                 eov = strchr(buf.buf, ' ');
 998                 if (!eov)
 999                         die("Malformed response in ref list: %s", buf.buf);
1000                 eon = strchr(eov + 1, ' ');
1001                 *eov = '\0';
1002                 if (eon)
1003                         *eon = '\0';
1004                 *tail = alloc_ref(eov + 1);
1005                 if (buf.buf[0] == '@')
1006                         (*tail)->symref = xstrdup(buf.buf + 1);
1007                 else if (buf.buf[0] != '?')
1008                         get_sha1_hex(buf.buf, (*tail)->old_sha1);
1009                 if (eon) {
1010                         if (has_attribute(eon + 1, "unchanged")) {
1011                                 (*tail)->status |= REF_STATUS_UPTODATE;
1012                                 read_ref((*tail)->name, (*tail)->old_sha1);
1013                         }
1014                 }
1015                 tail = &((*tail)->next);
1016         }
1017         if (debug)
1018                 fprintf(stderr, "Debug: Read ref listing.\n");
1019         strbuf_release(&buf);
1020
1021         for (posn = ret; posn; posn = posn->next)
1022                 resolve_remote_symref(posn, ret);
1023
1024         return ret;
1025 }
1026
1027 int transport_helper_init(struct transport *transport, const char *name)
1028 {
1029         struct helper_data *data = xcalloc(sizeof(*data), 1);
1030         data->name = name;
1031
1032         if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1033                 debug = 1;
1034
1035         transport->data = data;
1036         transport->set_option = set_helper_option;
1037         transport->get_refs_list = get_refs_list;
1038         transport->fetch = fetch;
1039         transport->push_refs = push_refs;
1040         transport->disconnect = release_helper;
1041         transport->connect = connect_helper;
1042         transport->smart_options = &(data->transport_options);
1043         return 0;
1044 }
1045
1046 /*
1047  * Linux pipes can buffer 65536 bytes at once (and most platforms can
1048  * buffer less), so attempt reads and writes with up to that size.
1049  */
1050 #define BUFFERSIZE 65536
1051 /* This should be enough to hold debugging message. */
1052 #define PBUFFERSIZE 8192
1053
1054 /* Print bidirectional transfer loop debug message. */
1055 __attribute__((format (printf, 1, 2)))
1056 static void transfer_debug(const char *fmt, ...)
1057 {
1058         va_list args;
1059         char msgbuf[PBUFFERSIZE];
1060         static int debug_enabled = -1;
1061
1062         if (debug_enabled < 0)
1063                 debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1064         if (!debug_enabled)
1065                 return;
1066
1067         va_start(args, fmt);
1068         vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1069         va_end(args);
1070         fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1071 }
1072
1073 /* Stream state: More data may be coming in this direction. */
1074 #define SSTATE_TRANSFERING 0
1075 /*
1076  * Stream state: No more data coming in this direction, flushing rest of
1077  * data.
1078  */
1079 #define SSTATE_FLUSHING 1
1080 /* Stream state: Transfer in this direction finished. */
1081 #define SSTATE_FINISHED 2
1082
1083 #define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1084 #define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1085 #define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1086
1087 /* Unidirectional transfer. */
1088 struct unidirectional_transfer {
1089         /* Source */
1090         int src;
1091         /* Destination */
1092         int dest;
1093         /* Is source socket? */
1094         int src_is_sock;
1095         /* Is destination socket? */
1096         int dest_is_sock;
1097         /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1098         int state;
1099         /* Buffer. */
1100         char buf[BUFFERSIZE];
1101         /* Buffer used. */
1102         size_t bufuse;
1103         /* Name of source. */
1104         const char *src_name;
1105         /* Name of destination. */
1106         const char *dest_name;
1107 };
1108
1109 /* Closes the target (for writing) if transfer has finished. */
1110 static void udt_close_if_finished(struct unidirectional_transfer *t)
1111 {
1112         if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1113                 t->state = SSTATE_FINISHED;
1114                 if (t->dest_is_sock)
1115                         shutdown(t->dest, SHUT_WR);
1116                 else
1117                         close(t->dest);
1118                 transfer_debug("Closed %s.", t->dest_name);
1119         }
1120 }
1121
1122 /*
1123  * Tries to read read data from source into buffer. If buffer is full,
1124  * no data is read. Returns 0 on success, -1 on error.
1125  */
1126 static int udt_do_read(struct unidirectional_transfer *t)
1127 {
1128         ssize_t bytes;
1129
1130         if (t->bufuse == BUFFERSIZE)
1131                 return 0;       /* No space for more. */
1132
1133         transfer_debug("%s is readable", t->src_name);
1134         bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1135         if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1136                 errno != EINTR) {
1137                 error("read(%s) failed: %s", t->src_name, strerror(errno));
1138                 return -1;
1139         } else if (bytes == 0) {
1140                 transfer_debug("%s EOF (with %i bytes in buffer)",
1141                         t->src_name, (int)t->bufuse);
1142                 t->state = SSTATE_FLUSHING;
1143         } else if (bytes > 0) {
1144                 t->bufuse += bytes;
1145                 transfer_debug("Read %i bytes from %s (buffer now at %i)",
1146                         (int)bytes, t->src_name, (int)t->bufuse);
1147         }
1148         return 0;
1149 }
1150
1151 /* Tries to write data from buffer into destination. If buffer is empty,
1152  * no data is written. Returns 0 on success, -1 on error.
1153  */
1154 static int udt_do_write(struct unidirectional_transfer *t)
1155 {
1156         ssize_t bytes;
1157
1158         if (t->bufuse == 0)
1159                 return 0;       /* Nothing to write. */
1160
1161         transfer_debug("%s is writable", t->dest_name);
1162         bytes = xwrite(t->dest, t->buf, t->bufuse);
1163         if (bytes < 0 && errno != EWOULDBLOCK) {
1164                 error("write(%s) failed: %s", t->dest_name, strerror(errno));
1165                 return -1;
1166         } else if (bytes > 0) {
1167                 t->bufuse -= bytes;
1168                 if (t->bufuse)
1169                         memmove(t->buf, t->buf + bytes, t->bufuse);
1170                 transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1171                         (int)bytes, t->dest_name, (int)t->bufuse);
1172         }
1173         return 0;
1174 }
1175
1176
1177 /* State of bidirectional transfer loop. */
1178 struct bidirectional_transfer_state {
1179         /* Direction from program to git. */
1180         struct unidirectional_transfer ptg;
1181         /* Direction from git to program. */
1182         struct unidirectional_transfer gtp;
1183 };
1184
1185 static void *udt_copy_task_routine(void *udt)
1186 {
1187         struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1188         while (t->state != SSTATE_FINISHED) {
1189                 if (STATE_NEEDS_READING(t->state))
1190                         if (udt_do_read(t))
1191                                 return NULL;
1192                 if (STATE_NEEDS_WRITING(t->state))
1193                         if (udt_do_write(t))
1194                                 return NULL;
1195                 if (STATE_NEEDS_CLOSING(t->state))
1196                         udt_close_if_finished(t);
1197         }
1198         return udt;     /* Just some non-NULL value. */
1199 }
1200
1201 #ifndef NO_PTHREADS
1202
1203 /*
1204  * Join thread, with appropriate errors on failure. Name is name for the
1205  * thread (for error messages). Returns 0 on success, 1 on failure.
1206  */
1207 static int tloop_join(pthread_t thread, const char *name)
1208 {
1209         int err;
1210         void *tret;
1211         err = pthread_join(thread, &tret);
1212         if (!tret) {
1213                 error("%s thread failed", name);
1214                 return 1;
1215         }
1216         if (err) {
1217                 error("%s thread failed to join: %s", name, strerror(err));
1218                 return 1;
1219         }
1220         return 0;
1221 }
1222
1223 /*
1224  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1225  * -1 on failure.
1226  */
1227 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1228 {
1229         pthread_t gtp_thread;
1230         pthread_t ptg_thread;
1231         int err;
1232         int ret = 0;
1233         err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1234                 &s->gtp);
1235         if (err)
1236                 die("Can't start thread for copying data: %s", strerror(err));
1237         err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1238                 &s->ptg);
1239         if (err)
1240                 die("Can't start thread for copying data: %s", strerror(err));
1241
1242         ret |= tloop_join(gtp_thread, "Git to program copy");
1243         ret |= tloop_join(ptg_thread, "Program to git copy");
1244         return ret;
1245 }
1246 #else
1247
1248 /* Close the source and target (for writing) for transfer. */
1249 static void udt_kill_transfer(struct unidirectional_transfer *t)
1250 {
1251         t->state = SSTATE_FINISHED;
1252         /*
1253          * Socket read end left open isn't a disaster if nobody
1254          * attempts to read from it (mingw compat headers do not
1255          * have SHUT_RD)...
1256          *
1257          * We can't fully close the socket since otherwise gtp
1258          * task would first close the socket it sends data to
1259          * while closing the ptg file descriptors.
1260          */
1261         if (!t->src_is_sock)
1262                 close(t->src);
1263         if (t->dest_is_sock)
1264                 shutdown(t->dest, SHUT_WR);
1265         else
1266                 close(t->dest);
1267 }
1268
1269 /*
1270  * Join process, with appropriate errors on failure. Name is name for the
1271  * process (for error messages). Returns 0 on success, 1 on failure.
1272  */
1273 static int tloop_join(pid_t pid, const char *name)
1274 {
1275         int tret;
1276         if (waitpid(pid, &tret, 0) < 0) {
1277                 error("%s process failed to wait: %s", name, strerror(errno));
1278                 return 1;
1279         }
1280         if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1281                 error("%s process failed", name);
1282                 return 1;
1283         }
1284         return 0;
1285 }
1286
1287 /*
1288  * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1289  * -1 on failure.
1290  */
1291 static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1292 {
1293         pid_t pid1, pid2;
1294         int ret = 0;
1295
1296         /* Fork thread #1: git to program. */
1297         pid1 = fork();
1298         if (pid1 < 0)
1299                 die_errno("Can't start thread for copying data");
1300         else if (pid1 == 0) {
1301                 udt_kill_transfer(&s->ptg);
1302                 exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1303         }
1304
1305         /* Fork thread #2: program to git. */
1306         pid2 = fork();
1307         if (pid2 < 0)
1308                 die_errno("Can't start thread for copying data");
1309         else if (pid2 == 0) {
1310                 udt_kill_transfer(&s->gtp);
1311                 exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1312         }
1313
1314         /*
1315          * Close both streams in parent as to not interfere with
1316          * end of file detection and wait for both tasks to finish.
1317          */
1318         udt_kill_transfer(&s->gtp);
1319         udt_kill_transfer(&s->ptg);
1320         ret |= tloop_join(pid1, "Git to program copy");
1321         ret |= tloop_join(pid2, "Program to git copy");
1322         return ret;
1323 }
1324 #endif
1325
1326 /*
1327  * Copies data from stdin to output and from input to stdout simultaneously.
1328  * Additionally filtering through given filter. If filter is NULL, uses
1329  * identity filter.
1330  */
1331 int bidirectional_transfer_loop(int input, int output)
1332 {
1333         struct bidirectional_transfer_state state;
1334
1335         /* Fill the state fields. */
1336         state.ptg.src = input;
1337         state.ptg.dest = 1;
1338         state.ptg.src_is_sock = (input == output);
1339         state.ptg.dest_is_sock = 0;
1340         state.ptg.state = SSTATE_TRANSFERING;
1341         state.ptg.bufuse = 0;
1342         state.ptg.src_name = "remote input";
1343         state.ptg.dest_name = "stdout";
1344
1345         state.gtp.src = 0;
1346         state.gtp.dest = output;
1347         state.gtp.src_is_sock = 0;
1348         state.gtp.dest_is_sock = (input == output);
1349         state.gtp.state = SSTATE_TRANSFERING;
1350         state.gtp.bufuse = 0;
1351         state.gtp.src_name = "stdin";
1352         state.gtp.dest_name = "remote output";
1353
1354         return tloop_spawnwait_tasks(&state);
1355 }