transport-helper.c

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