transport-helper.con commit Merge branch 'fc/remote-hg' (c8c82b1)
   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
  15static int debug;
  16
  17struct 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
  41static 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
  50static 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
  66static int recvline(struct helper_data *helper, struct strbuf *buffer)
  67{
  68        return recvline_fh(helper->out, buffer);
  69}
  70
  71static void xchgline(struct helper_data *helper, struct strbuf *buffer)
  72{
  73        sendline(helper, buffer);
  74        recvline(helper, buffer);
  75}
  76
  77static 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
  85static 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
  95static 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
 104static 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                }
 220                free(refspecs);
 221        }
 222        strbuf_release(&buf);
 223        if (debug)
 224                fprintf(stderr, "Debug: Capabilities complete.\n");
 225        return data->helper;
 226}
 227
 228static int disconnect_helper(struct transport *transport)
 229{
 230        struct helper_data *data = transport->data;
 231        int res = 0;
 232
 233        if (data->helper) {
 234                if (debug)
 235                        fprintf(stderr, "Debug: Disconnecting.\n");
 236                if (!data->no_disconnect_req) {
 237                        /*
 238                         * Ignore write errors; there's nothing we can do,
 239                         * since we're about to close the pipe anyway. And the
 240                         * most likely error is EPIPE due to the helper dying
 241                         * to report an error itself.
 242                         */
 243                        sigchain_push(SIGPIPE, SIG_IGN);
 244                        xwrite(data->helper->in, "\n", 1);
 245                        sigchain_pop(SIGPIPE);
 246                }
 247                close(data->helper->in);
 248                close(data->helper->out);
 249                fclose(data->out);
 250                res = finish_command(data->helper);
 251                argv_array_free_detached(data->helper->argv);
 252                free(data->helper);
 253                data->helper = NULL;
 254        }
 255        return res;
 256}
 257
 258static const char *unsupported_options[] = {
 259        TRANS_OPT_UPLOADPACK,
 260        TRANS_OPT_RECEIVEPACK,
 261        TRANS_OPT_THIN,
 262        TRANS_OPT_KEEP
 263        };
 264static const char *boolean_options[] = {
 265        TRANS_OPT_THIN,
 266        TRANS_OPT_KEEP,
 267        TRANS_OPT_FOLLOWTAGS
 268        };
 269
 270static int set_helper_option(struct transport *transport,
 271                          const char *name, const char *value)
 272{
 273        struct helper_data *data = transport->data;
 274        struct strbuf buf = STRBUF_INIT;
 275        int i, ret, is_bool = 0;
 276
 277        get_helper(transport);
 278
 279        if (!data->option)
 280                return 1;
 281
 282        for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 283                if (!strcmp(name, unsupported_options[i]))
 284                        return 1;
 285        }
 286
 287        for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 288                if (!strcmp(name, boolean_options[i])) {
 289                        is_bool = 1;
 290                        break;
 291                }
 292        }
 293
 294        strbuf_addf(&buf, "option %s ", name);
 295        if (is_bool)
 296                strbuf_addstr(&buf, value ? "true" : "false");
 297        else
 298                quote_c_style(value, &buf, NULL, 0);
 299        strbuf_addch(&buf, '\n');
 300
 301        xchgline(data, &buf);
 302
 303        if (!strcmp(buf.buf, "ok"))
 304                ret = 0;
 305        else if (!prefixcmp(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
 317static 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
 331static 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
 342static 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
 351        for (i = 0; i < nr_heads; i++) {
 352                const struct ref *posn = to_fetch[i];
 353                if (posn->status & REF_STATUS_UPTODATE)
 354                        continue;
 355
 356                strbuf_addf(&buf, "fetch %s %s\n",
 357                            sha1_to_hex(posn->old_sha1), posn->name);
 358        }
 359
 360        strbuf_addch(&buf, '\n');
 361        sendline(data, &buf);
 362
 363        while (1) {
 364                recvline(data, &buf);
 365
 366                if (!prefixcmp(buf.buf, "lock ")) {
 367                        const char *name = buf.buf + 5;
 368                        if (transport->pack_lockfile)
 369                                warning("%s also locked %s", data->name, name);
 370                        else
 371                                transport->pack_lockfile = xstrdup(name);
 372                }
 373                else if (!buf.len)
 374                        break;
 375                else
 376                        warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 377        }
 378        strbuf_release(&buf);
 379        return 0;
 380}
 381
 382static int get_importer(struct transport *transport, struct child_process *fastimport)
 383{
 384        struct child_process *helper = get_helper(transport);
 385        struct helper_data *data = transport->data;
 386        struct argv_array argv = ARGV_ARRAY_INIT;
 387        int cat_blob_fd, code;
 388        memset(fastimport, 0, sizeof(*fastimport));
 389        fastimport->in = helper->out;
 390        argv_array_push(&argv, "fast-import");
 391        argv_array_push(&argv, debug ? "--stats" : "--quiet");
 392
 393        if (data->bidi_import) {
 394                cat_blob_fd = xdup(helper->in);
 395                argv_array_pushf(&argv, "--cat-blob-fd=%d", cat_blob_fd);
 396        }
 397        fastimport->argv = argv.argv;
 398        fastimport->git_cmd = 1;
 399
 400        code = start_command(fastimport);
 401        return code;
 402}
 403
 404static int get_exporter(struct transport *transport,
 405                        struct child_process *fastexport,
 406                        struct string_list *revlist_args)
 407{
 408        struct helper_data *data = transport->data;
 409        struct child_process *helper = get_helper(transport);
 410        int argc = 0, i;
 411        memset(fastexport, 0, sizeof(*fastexport));
 412
 413        /* we need to duplicate helper->in because we want to use it after
 414         * fastexport is done with it. */
 415        fastexport->out = dup(helper->in);
 416        fastexport->argv = xcalloc(6 + revlist_args->nr, sizeof(*fastexport->argv));
 417        fastexport->argv[argc++] = "fast-export";
 418        fastexport->argv[argc++] = "--use-done-feature";
 419        fastexport->argv[argc++] = data->signed_tags ?
 420                "--signed-tags=verbatim" : "--signed-tags=warn-strip";
 421        if (data->export_marks)
 422                fastexport->argv[argc++] = data->export_marks;
 423        if (data->import_marks)
 424                fastexport->argv[argc++] = data->import_marks;
 425
 426        for (i = 0; i < revlist_args->nr; i++)
 427                fastexport->argv[argc++] = revlist_args->items[i].string;
 428
 429        fastexport->git_cmd = 1;
 430        return start_command(fastexport);
 431}
 432
 433static int fetch_with_import(struct transport *transport,
 434                             int nr_heads, struct ref **to_fetch)
 435{
 436        struct child_process fastimport;
 437        struct helper_data *data = transport->data;
 438        int i;
 439        struct ref *posn;
 440        struct strbuf buf = STRBUF_INIT;
 441
 442        get_helper(transport);
 443
 444        if (get_importer(transport, &fastimport))
 445                die("Couldn't run fast-import");
 446
 447        for (i = 0; i < nr_heads; i++) {
 448                posn = to_fetch[i];
 449                if (posn->status & REF_STATUS_UPTODATE)
 450                        continue;
 451
 452                strbuf_addf(&buf, "import %s\n", posn->name);
 453                sendline(data, &buf);
 454                strbuf_reset(&buf);
 455        }
 456
 457        write_constant(data->helper->in, "\n");
 458        /*
 459         * remote-helpers that advertise the bidi-import capability are required to
 460         * buffer the complete batch of import commands until this newline before
 461         * sending data to fast-import.
 462         * These helpers read back data from fast-import on their stdin, which could
 463         * be mixed with import commands, otherwise.
 464         */
 465
 466        if (finish_command(&fastimport))
 467                die("Error while running fast-import");
 468        argv_array_free_detached(fastimport.argv);
 469
 470        /*
 471         * The fast-import stream of a remote helper that advertises
 472         * the "refspec" capability writes to the refs named after the
 473         * right hand side of the first refspec matching each ref we
 474         * were fetching.
 475         *
 476         * (If no "refspec" capability was specified, for historical
 477         * reasons we default to *:*.)
 478         *
 479         * Store the result in to_fetch[i].old_sha1.  Callers such
 480         * as "git fetch" can use the value to write feedback to the
 481         * terminal, populate FETCH_HEAD, and determine what new value
 482         * should be written to peer_ref if the update is a
 483         * fast-forward or this is a forced update.
 484         */
 485        for (i = 0; i < nr_heads; i++) {
 486                char *private;
 487                posn = to_fetch[i];
 488                if (posn->status & REF_STATUS_UPTODATE)
 489                        continue;
 490                if (data->refspecs)
 491                        private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 492                else
 493                        private = xstrdup(posn->name);
 494                if (private) {
 495                        read_ref(private, posn->old_sha1);
 496                        free(private);
 497                }
 498        }
 499        strbuf_release(&buf);
 500        return 0;
 501}
 502
 503static int process_connect_service(struct transport *transport,
 504                                   const char *name, const char *exec)
 505{
 506        struct helper_data *data = transport->data;
 507        struct strbuf cmdbuf = STRBUF_INIT;
 508        struct child_process *helper;
 509        int r, duped, ret = 0;
 510        FILE *input;
 511
 512        helper = get_helper(transport);
 513
 514        /*
 515         * Yes, dup the pipe another time, as we need unbuffered version
 516         * of input pipe as FILE*. fclose() closes the underlying fd and
 517         * stream buffering only can be changed before first I/O operation
 518         * on it.
 519         */
 520        duped = dup(helper->out);
 521        if (duped < 0)
 522                die_errno("Can't dup helper output fd");
 523        input = xfdopen(duped, "r");
 524        setvbuf(input, NULL, _IONBF, 0);
 525
 526        /*
 527         * Handle --upload-pack and friends. This is fire and forget...
 528         * just warn if it fails.
 529         */
 530        if (strcmp(name, exec)) {
 531                r = set_helper_option(transport, "servpath", exec);
 532                if (r > 0)
 533                        warning("Setting remote service path not supported by protocol.");
 534                else if (r < 0)
 535                        warning("Invalid remote service path.");
 536        }
 537
 538        if (data->connect)
 539                strbuf_addf(&cmdbuf, "connect %s\n", name);
 540        else
 541                goto exit;
 542
 543        sendline(data, &cmdbuf);
 544        recvline_fh(input, &cmdbuf);
 545        if (!strcmp(cmdbuf.buf, "")) {
 546                data->no_disconnect_req = 1;
 547                if (debug)
 548                        fprintf(stderr, "Debug: Smart transport connection "
 549                                "ready.\n");
 550                ret = 1;
 551        } else if (!strcmp(cmdbuf.buf, "fallback")) {
 552                if (debug)
 553                        fprintf(stderr, "Debug: Falling back to dumb "
 554                                "transport.\n");
 555        } else
 556                die("Unknown response to connect: %s",
 557                        cmdbuf.buf);
 558
 559exit:
 560        fclose(input);
 561        return ret;
 562}
 563
 564static int process_connect(struct transport *transport,
 565                                     int for_push)
 566{
 567        struct helper_data *data = transport->data;
 568        const char *name;
 569        const char *exec;
 570
 571        name = for_push ? "git-receive-pack" : "git-upload-pack";
 572        if (for_push)
 573                exec = data->transport_options.receivepack;
 574        else
 575                exec = data->transport_options.uploadpack;
 576
 577        return process_connect_service(transport, name, exec);
 578}
 579
 580static int connect_helper(struct transport *transport, const char *name,
 581                   const char *exec, int fd[2])
 582{
 583        struct helper_data *data = transport->data;
 584
 585        /* Get_helper so connect is inited. */
 586        get_helper(transport);
 587        if (!data->connect)
 588                die("Operation not supported by protocol.");
 589
 590        if (!process_connect_service(transport, name, exec))
 591                die("Can't connect to subservice %s.", name);
 592
 593        fd[0] = data->helper->out;
 594        fd[1] = data->helper->in;
 595        return 0;
 596}
 597
 598static int fetch(struct transport *transport,
 599                 int nr_heads, struct ref **to_fetch)
 600{
 601        struct helper_data *data = transport->data;
 602        int i, count;
 603
 604        if (process_connect(transport, 0)) {
 605                do_take_over(transport);
 606                return transport->fetch(transport, nr_heads, to_fetch);
 607        }
 608
 609        count = 0;
 610        for (i = 0; i < nr_heads; i++)
 611                if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 612                        count++;
 613
 614        if (!count)
 615                return 0;
 616
 617        if (data->fetch)
 618                return fetch_with_fetch(transport, nr_heads, to_fetch);
 619
 620        if (data->import)
 621                return fetch_with_import(transport, nr_heads, to_fetch);
 622
 623        return -1;
 624}
 625
 626static void push_update_ref_status(struct strbuf *buf,
 627                                   struct ref **ref,
 628                                   struct ref *remote_refs)
 629{
 630        char *refname, *msg;
 631        int status;
 632
 633        if (!prefixcmp(buf->buf, "ok ")) {
 634                status = REF_STATUS_OK;
 635                refname = buf->buf + 3;
 636        } else if (!prefixcmp(buf->buf, "error ")) {
 637                status = REF_STATUS_REMOTE_REJECT;
 638                refname = buf->buf + 6;
 639        } else
 640                die("expected ok/error, helper said '%s'", buf->buf);
 641
 642        msg = strchr(refname, ' ');
 643        if (msg) {
 644                struct strbuf msg_buf = STRBUF_INIT;
 645                const char *end;
 646
 647                *msg++ = '\0';
 648                if (!unquote_c_style(&msg_buf, msg, &end))
 649                        msg = strbuf_detach(&msg_buf, NULL);
 650                else
 651                        msg = xstrdup(msg);
 652                strbuf_release(&msg_buf);
 653
 654                if (!strcmp(msg, "no match")) {
 655                        status = REF_STATUS_NONE;
 656                        free(msg);
 657                        msg = NULL;
 658                }
 659                else if (!strcmp(msg, "up to date")) {
 660                        status = REF_STATUS_UPTODATE;
 661                        free(msg);
 662                        msg = NULL;
 663                }
 664                else if (!strcmp(msg, "non-fast forward")) {
 665                        status = REF_STATUS_REJECT_NONFASTFORWARD;
 666                        free(msg);
 667                        msg = NULL;
 668                }
 669                else if (!strcmp(msg, "already exists")) {
 670                        status = REF_STATUS_REJECT_ALREADY_EXISTS;
 671                        free(msg);
 672                        msg = NULL;
 673                }
 674                else if (!strcmp(msg, "fetch first")) {
 675                        status = REF_STATUS_REJECT_FETCH_FIRST;
 676                        free(msg);
 677                        msg = NULL;
 678                }
 679                else if (!strcmp(msg, "needs force")) {
 680                        status = REF_STATUS_REJECT_NEEDS_FORCE;
 681                        free(msg);
 682                        msg = NULL;
 683                }
 684        }
 685
 686        if (*ref)
 687                *ref = find_ref_by_name(*ref, refname);
 688        if (!*ref)
 689                *ref = find_ref_by_name(remote_refs, refname);
 690        if (!*ref) {
 691                warning("helper reported unexpected status of %s", refname);
 692                return;
 693        }
 694
 695        if ((*ref)->status != REF_STATUS_NONE) {
 696                /*
 697                 * Earlier, the ref was marked not to be pushed, so ignore the ref
 698                 * status reported by the remote helper if the latter is 'no match'.
 699                 */
 700                if (status == REF_STATUS_NONE)
 701                        return;
 702        }
 703
 704        (*ref)->status = status;
 705        (*ref)->remote_status = msg;
 706}
 707
 708static void push_update_refs_status(struct helper_data *data,
 709                                    struct ref *remote_refs)
 710{
 711        struct strbuf buf = STRBUF_INIT;
 712        struct ref *ref = remote_refs;
 713        for (;;) {
 714                recvline(data, &buf);
 715                if (!buf.len)
 716                        break;
 717
 718                push_update_ref_status(&buf, &ref, remote_refs);
 719        }
 720        strbuf_release(&buf);
 721}
 722
 723static int push_refs_with_push(struct transport *transport,
 724                struct ref *remote_refs, int flags)
 725{
 726        int force_all = flags & TRANSPORT_PUSH_FORCE;
 727        int mirror = flags & TRANSPORT_PUSH_MIRROR;
 728        struct helper_data *data = transport->data;
 729        struct strbuf buf = STRBUF_INIT;
 730        struct ref *ref;
 731
 732        get_helper(transport);
 733        if (!data->push)
 734                return 1;
 735
 736        for (ref = remote_refs; ref; ref = ref->next) {
 737                if (!ref->peer_ref && !mirror)
 738                        continue;
 739
 740                /* Check for statuses set by set_ref_status_for_push() */
 741                switch (ref->status) {
 742                case REF_STATUS_REJECT_NONFASTFORWARD:
 743                case REF_STATUS_REJECT_ALREADY_EXISTS:
 744                case REF_STATUS_UPTODATE:
 745                        continue;
 746                default:
 747                        ; /* do nothing */
 748                }
 749
 750                if (force_all)
 751                        ref->force = 1;
 752
 753                strbuf_addstr(&buf, "push ");
 754                if (!ref->deletion) {
 755                        if (ref->force)
 756                                strbuf_addch(&buf, '+');
 757                        if (ref->peer_ref)
 758                                strbuf_addstr(&buf, ref->peer_ref->name);
 759                        else
 760                                strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 761                }
 762                strbuf_addch(&buf, ':');
 763                strbuf_addstr(&buf, ref->name);
 764                strbuf_addch(&buf, '\n');
 765        }
 766        if (buf.len == 0)
 767                return 0;
 768
 769        standard_options(transport);
 770
 771        if (flags & TRANSPORT_PUSH_DRY_RUN) {
 772                if (set_helper_option(transport, "dry-run", "true") != 0)
 773                        die("helper %s does not support dry-run", data->name);
 774        }
 775
 776        strbuf_addch(&buf, '\n');
 777        sendline(data, &buf);
 778        strbuf_release(&buf);
 779
 780        push_update_refs_status(data, remote_refs);
 781        return 0;
 782}
 783
 784static int push_refs_with_export(struct transport *transport,
 785                struct ref *remote_refs, int flags)
 786{
 787        struct ref *ref;
 788        struct child_process *helper, exporter;
 789        struct helper_data *data = transport->data;
 790        struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 791        struct strbuf buf = STRBUF_INIT;
 792
 793        helper = get_helper(transport);
 794
 795        write_constant(helper->in, "export\n");
 796
 797        strbuf_reset(&buf);
 798
 799        for (ref = remote_refs; ref; ref = ref->next) {
 800                char *private;
 801                unsigned char sha1[20];
 802
 803                if (!data->refspecs)
 804                        continue;
 805                private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 806                if (private && !get_sha1(private, sha1)) {
 807                        strbuf_addf(&buf, "^%s", private);
 808                        string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 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
 830static 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
 856static 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
 872static 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
 930int 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. */
 958static 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. */
 990struct 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. */
1012static 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 */
1028static 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 */
1056static 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. */
1081struct 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
1088static 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 */
1110static 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 */
1130static 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. */
1152static 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 */
1176static 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 */
1194static 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 */
1234int 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}