transport-helper.con commit stylefix: asterisks stick to the variable, not the type (24d36f1)
   1#include "cache.h"
   2#include "transport.h"
   3#include "quote.h"
   4#include "run-command.h"
   5#include "commit.h"
   6#include "diff.h"
   7#include "revision.h"
   8#include "quote.h"
   9#include "remote.h"
  10#include "string-list.h"
  11#include "thread-utils.h"
  12#include "sigchain.h"
  13#include "argv-array.h"
  14#include "refs.h"
  15
  16static int debug;
  17
  18struct helper_data {
  19        const char *name;
  20        struct child_process *helper;
  21        FILE *out;
  22        unsigned fetch : 1,
  23                import : 1,
  24                bidi_import : 1,
  25                export : 1,
  26                option : 1,
  27                push : 1,
  28                connect : 1,
  29                signed_tags : 1,
  30                check_connectivity : 1,
  31                no_disconnect_req : 1,
  32                no_private_update : 1;
  33        char *export_marks;
  34        char *import_marks;
  35        /* These go from remote name (as in "list") to private name */
  36        struct refspec *refspecs;
  37        int refspec_nr;
  38        /* Transport options for fetch-pack/send-pack (should one of
  39         * those be invoked).
  40         */
  41        struct git_transport_options transport_options;
  42};
  43
  44static void sendline(struct helper_data *helper, struct strbuf *buffer)
  45{
  46        if (debug)
  47                fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
  48        if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
  49                != buffer->len)
  50                die_errno("Full write to remote helper failed");
  51}
  52
  53static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
  54{
  55        strbuf_reset(buffer);
  56        if (debug)
  57                fprintf(stderr, "Debug: Remote helper: Waiting...\n");
  58        if (strbuf_getline(buffer, helper, '\n') == EOF) {
  59                if (debug)
  60                        fprintf(stderr, "Debug: Remote helper quit.\n");
  61                return 1;
  62        }
  63
  64        if (debug)
  65                fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
  66        return 0;
  67}
  68
  69static int recvline(struct helper_data *helper, struct strbuf *buffer)
  70{
  71        return recvline_fh(helper->out, buffer, helper->name);
  72}
  73
  74static void write_constant(int fd, const char *str)
  75{
  76        if (debug)
  77                fprintf(stderr, "Debug: Remote helper: -> %s", str);
  78        if (write_in_full(fd, str, strlen(str)) != strlen(str))
  79                die_errno("Full write to remote helper failed");
  80}
  81
  82static const char *remove_ext_force(const char *url)
  83{
  84        if (url) {
  85                const char *colon = strchr(url, ':');
  86                if (colon && colon[1] == ':')
  87                        return colon + 2;
  88        }
  89        return url;
  90}
  91
  92static void do_take_over(struct transport *transport)
  93{
  94        struct helper_data *data;
  95        data = (struct helper_data *)transport->data;
  96        transport_take_over(transport, data->helper);
  97        fclose(data->out);
  98        free(data);
  99}
 100
 101static struct child_process *get_helper(struct transport *transport)
 102{
 103        struct helper_data *data = transport->data;
 104        struct strbuf buf = STRBUF_INIT;
 105        struct child_process *helper;
 106        const char **refspecs = NULL;
 107        int refspec_nr = 0;
 108        int refspec_alloc = 0;
 109        int duped;
 110        int code;
 111        char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
 112        const char *helper_env[] = {
 113                git_dir_buf,
 114                NULL
 115        };
 116
 117
 118        if (data->helper)
 119                return data->helper;
 120
 121        helper = xcalloc(1, sizeof(*helper));
 122        helper->in = -1;
 123        helper->out = -1;
 124        helper->err = 0;
 125        argv_array_pushf(&helper->args, "git-remote-%s", data->name);
 126        argv_array_push(&helper->args, transport->remote->name);
 127        argv_array_push(&helper->args, remove_ext_force(transport->url));
 128        helper->git_cmd = 0;
 129        helper->silent_exec_failure = 1;
 130
 131        snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
 132        helper->env = helper_env;
 133
 134        code = start_command(helper);
 135        if (code < 0 && errno == ENOENT)
 136                die("Unable to find remote helper for '%s'", data->name);
 137        else if (code != 0)
 138                exit(code);
 139
 140        data->helper = helper;
 141        data->no_disconnect_req = 0;
 142
 143        /*
 144         * Open the output as FILE* so strbuf_getline() can be used.
 145         * Do this with duped fd because fclose() will close the fd,
 146         * and stuff like taking over will require the fd to remain.
 147         */
 148        duped = dup(helper->out);
 149        if (duped < 0)
 150                die_errno("Can't dup helper output fd");
 151        data->out = xfdopen(duped, "r");
 152
 153        write_constant(helper->in, "capabilities\n");
 154
 155        while (1) {
 156                const char *capname, *arg;
 157                int mandatory = 0;
 158                if (recvline(data, &buf))
 159                        exit(128);
 160
 161                if (!*buf.buf)
 162                        break;
 163
 164                if (*buf.buf == '*') {
 165                        capname = buf.buf + 1;
 166                        mandatory = 1;
 167                } else
 168                        capname = buf.buf;
 169
 170                if (debug)
 171                        fprintf(stderr, "Debug: Got cap %s\n", capname);
 172                if (!strcmp(capname, "fetch"))
 173                        data->fetch = 1;
 174                else if (!strcmp(capname, "option"))
 175                        data->option = 1;
 176                else if (!strcmp(capname, "push"))
 177                        data->push = 1;
 178                else if (!strcmp(capname, "import"))
 179                        data->import = 1;
 180                else if (!strcmp(capname, "bidi-import"))
 181                        data->bidi_import = 1;
 182                else if (!strcmp(capname, "export"))
 183                        data->export = 1;
 184                else if (!strcmp(capname, "check-connectivity"))
 185                        data->check_connectivity = 1;
 186                else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
 187                        ALLOC_GROW(refspecs,
 188                                   refspec_nr + 1,
 189                                   refspec_alloc);
 190                        refspecs[refspec_nr++] = xstrdup(arg);
 191                } else if (!strcmp(capname, "connect")) {
 192                        data->connect = 1;
 193                } else if (!strcmp(capname, "signed-tags")) {
 194                        data->signed_tags = 1;
 195                } else if (skip_prefix(capname, "export-marks ", &arg)) {
 196                        data->export_marks = xstrdup(arg);
 197                } else if (skip_prefix(capname, "import-marks ", &arg)) {
 198                        data->import_marks = xstrdup(arg);
 199                } else if (starts_with(capname, "no-private-update")) {
 200                        data->no_private_update = 1;
 201                } else if (mandatory) {
 202                        die("Unknown mandatory capability %s. This remote "
 203                            "helper probably needs newer version of Git.",
 204                            capname);
 205                }
 206        }
 207        if (refspecs) {
 208                int i;
 209                data->refspec_nr = refspec_nr;
 210                data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 211                for (i = 0; i < refspec_nr; i++)
 212                        free((char *)refspecs[i]);
 213                free(refspecs);
 214        } else if (data->import || data->bidi_import || data->export) {
 215                warning("This remote helper should implement refspec capability.");
 216        }
 217        strbuf_release(&buf);
 218        if (debug)
 219                fprintf(stderr, "Debug: Capabilities complete.\n");
 220        return data->helper;
 221}
 222
 223static int disconnect_helper(struct transport *transport)
 224{
 225        struct helper_data *data = transport->data;
 226        int res = 0;
 227
 228        if (data->helper) {
 229                if (debug)
 230                        fprintf(stderr, "Debug: Disconnecting.\n");
 231                if (!data->no_disconnect_req) {
 232                        /*
 233                         * Ignore write errors; there's nothing we can do,
 234                         * since we're about to close the pipe anyway. And the
 235                         * most likely error is EPIPE due to the helper dying
 236                         * to report an error itself.
 237                         */
 238                        sigchain_push(SIGPIPE, SIG_IGN);
 239                        xwrite(data->helper->in, "\n", 1);
 240                        sigchain_pop(SIGPIPE);
 241                }
 242                close(data->helper->in);
 243                close(data->helper->out);
 244                fclose(data->out);
 245                res = finish_command(data->helper);
 246                free(data->helper);
 247                data->helper = NULL;
 248        }
 249        return res;
 250}
 251
 252static const char *unsupported_options[] = {
 253        TRANS_OPT_UPLOADPACK,
 254        TRANS_OPT_RECEIVEPACK,
 255        TRANS_OPT_THIN,
 256        TRANS_OPT_KEEP
 257        };
 258
 259static const char *boolean_options[] = {
 260        TRANS_OPT_THIN,
 261        TRANS_OPT_KEEP,
 262        TRANS_OPT_FOLLOWTAGS
 263        };
 264
 265static int set_helper_option(struct transport *transport,
 266                          const char *name, const char *value)
 267{
 268        struct helper_data *data = transport->data;
 269        struct strbuf buf = STRBUF_INIT;
 270        int i, ret, is_bool = 0;
 271
 272        get_helper(transport);
 273
 274        if (!data->option)
 275                return 1;
 276
 277        for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
 278                if (!strcmp(name, unsupported_options[i]))
 279                        return 1;
 280        }
 281
 282        for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
 283                if (!strcmp(name, boolean_options[i])) {
 284                        is_bool = 1;
 285                        break;
 286                }
 287        }
 288
 289        strbuf_addf(&buf, "option %s ", name);
 290        if (is_bool)
 291                strbuf_addstr(&buf, value ? "true" : "false");
 292        else
 293                quote_c_style(value, &buf, NULL, 0);
 294        strbuf_addch(&buf, '\n');
 295
 296        sendline(data, &buf);
 297        if (recvline(data, &buf))
 298                exit(128);
 299
 300        if (!strcmp(buf.buf, "ok"))
 301                ret = 0;
 302        else if (starts_with(buf.buf, "error")) {
 303                ret = -1;
 304        } else if (!strcmp(buf.buf, "unsupported"))
 305                ret = 1;
 306        else {
 307                warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 308                ret = 1;
 309        }
 310        strbuf_release(&buf);
 311        return ret;
 312}
 313
 314static void standard_options(struct transport *t)
 315{
 316        char buf[16];
 317        int n;
 318        int v = t->verbose;
 319
 320        set_helper_option(t, "progress", t->progress ? "true" : "false");
 321
 322        n = snprintf(buf, sizeof(buf), "%d", v + 1);
 323        if (n >= sizeof(buf))
 324                die("impossibly large verbosity value");
 325        set_helper_option(t, "verbosity", buf);
 326}
 327
 328static int release_helper(struct transport *transport)
 329{
 330        int res = 0;
 331        struct helper_data *data = transport->data;
 332        free_refspec(data->refspec_nr, data->refspecs);
 333        data->refspecs = NULL;
 334        res = disconnect_helper(transport);
 335        free(transport->data);
 336        return res;
 337}
 338
 339static int fetch_with_fetch(struct transport *transport,
 340                            int nr_heads, struct ref **to_fetch)
 341{
 342        struct helper_data *data = transport->data;
 343        int i;
 344        struct strbuf buf = STRBUF_INIT;
 345
 346        standard_options(transport);
 347        if (data->check_connectivity &&
 348            data->transport_options.check_self_contained_and_connected)
 349                set_helper_option(transport, "check-connectivity", "true");
 350
 351        if (transport->cloning)
 352                set_helper_option(transport, "cloning", "true");
 353
 354        if (data->transport_options.update_shallow)
 355                set_helper_option(transport, "update-shallow", "true");
 356
 357        for (i = 0; i < nr_heads; i++) {
 358                const struct ref *posn = to_fetch[i];
 359                if (posn->status & REF_STATUS_UPTODATE)
 360                        continue;
 361
 362                strbuf_addf(&buf, "fetch %s %s\n",
 363                            sha1_to_hex(posn->old_sha1), posn->name);
 364        }
 365
 366        strbuf_addch(&buf, '\n');
 367        sendline(data, &buf);
 368
 369        while (1) {
 370                if (recvline(data, &buf))
 371                        exit(128);
 372
 373                if (starts_with(buf.buf, "lock ")) {
 374                        const char *name = buf.buf + 5;
 375                        if (transport->pack_lockfile)
 376                                warning("%s also locked %s", data->name, name);
 377                        else
 378                                transport->pack_lockfile = xstrdup(name);
 379                }
 380                else if (data->check_connectivity &&
 381                         data->transport_options.check_self_contained_and_connected &&
 382                         !strcmp(buf.buf, "connectivity-ok"))
 383                        data->transport_options.self_contained_and_connected = 1;
 384                else if (!buf.len)
 385                        break;
 386                else
 387                        warning("%s unexpectedly said: '%s'", data->name, buf.buf);
 388        }
 389        strbuf_release(&buf);
 390        return 0;
 391}
 392
 393static int get_importer(struct transport *transport, struct child_process *fastimport)
 394{
 395        struct child_process *helper = get_helper(transport);
 396        struct helper_data *data = transport->data;
 397        int cat_blob_fd, code;
 398        memset(fastimport, 0, sizeof(*fastimport));
 399        fastimport->in = helper->out;
 400        argv_array_push(&fastimport->args, "fast-import");
 401        argv_array_push(&fastimport->args, debug ? "--stats" : "--quiet");
 402
 403        if (data->bidi_import) {
 404                cat_blob_fd = xdup(helper->in);
 405                argv_array_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
 406        }
 407        fastimport->git_cmd = 1;
 408
 409        code = start_command(fastimport);
 410        return code;
 411}
 412
 413static int get_exporter(struct transport *transport,
 414                        struct child_process *fastexport,
 415                        struct string_list *revlist_args)
 416{
 417        struct helper_data *data = transport->data;
 418        struct child_process *helper = get_helper(transport);
 419        int i;
 420
 421        memset(fastexport, 0, sizeof(*fastexport));
 422
 423        /* we need to duplicate helper->in because we want to use it after
 424         * fastexport is done with it. */
 425        fastexport->out = dup(helper->in);
 426        argv_array_push(&fastexport->args, "fast-export");
 427        argv_array_push(&fastexport->args, "--use-done-feature");
 428        argv_array_push(&fastexport->args, data->signed_tags ?
 429                "--signed-tags=verbatim" : "--signed-tags=warn-strip");
 430        if (data->export_marks)
 431                argv_array_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
 432        if (data->import_marks)
 433                argv_array_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);
 434
 435        for (i = 0; i < revlist_args->nr; i++)
 436                argv_array_push(&fastexport->args, revlist_args->items[i].string);
 437
 438        fastexport->git_cmd = 1;
 439        return start_command(fastexport);
 440}
 441
 442static int fetch_with_import(struct transport *transport,
 443                             int nr_heads, struct ref **to_fetch)
 444{
 445        struct child_process fastimport;
 446        struct helper_data *data = transport->data;
 447        int i;
 448        struct ref *posn;
 449        struct strbuf buf = STRBUF_INIT;
 450
 451        get_helper(transport);
 452
 453        if (get_importer(transport, &fastimport))
 454                die("Couldn't run fast-import");
 455
 456        for (i = 0; i < nr_heads; i++) {
 457                posn = to_fetch[i];
 458                if (posn->status & REF_STATUS_UPTODATE)
 459                        continue;
 460
 461                strbuf_addf(&buf, "import %s\n", posn->name);
 462                sendline(data, &buf);
 463                strbuf_reset(&buf);
 464        }
 465
 466        write_constant(data->helper->in, "\n");
 467        /*
 468         * remote-helpers that advertise the bidi-import capability are required to
 469         * buffer the complete batch of import commands until this newline before
 470         * sending data to fast-import.
 471         * These helpers read back data from fast-import on their stdin, which could
 472         * be mixed with import commands, otherwise.
 473         */
 474
 475        if (finish_command(&fastimport))
 476                die("Error while running fast-import");
 477
 478        /*
 479         * The fast-import stream of a remote helper that advertises
 480         * the "refspec" capability writes to the refs named after the
 481         * right hand side of the first refspec matching each ref we
 482         * were fetching.
 483         *
 484         * (If no "refspec" capability was specified, for historical
 485         * reasons we default to the equivalent of *:*.)
 486         *
 487         * Store the result in to_fetch[i].old_sha1.  Callers such
 488         * as "git fetch" can use the value to write feedback to the
 489         * terminal, populate FETCH_HEAD, and determine what new value
 490         * should be written to peer_ref if the update is a
 491         * fast-forward or this is a forced update.
 492         */
 493        for (i = 0; i < nr_heads; i++) {
 494                char *private;
 495                posn = to_fetch[i];
 496                if (posn->status & REF_STATUS_UPTODATE)
 497                        continue;
 498                if (data->refspecs)
 499                        private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 500                else
 501                        private = xstrdup(posn->name);
 502                if (private) {
 503                        read_ref(private, posn->old_sha1);
 504                        free(private);
 505                }
 506        }
 507        strbuf_release(&buf);
 508        return 0;
 509}
 510
 511static int process_connect_service(struct transport *transport,
 512                                   const char *name, const char *exec)
 513{
 514        struct helper_data *data = transport->data;
 515        struct strbuf cmdbuf = STRBUF_INIT;
 516        struct child_process *helper;
 517        int r, duped, ret = 0;
 518        FILE *input;
 519
 520        helper = get_helper(transport);
 521
 522        /*
 523         * Yes, dup the pipe another time, as we need unbuffered version
 524         * of input pipe as FILE*. fclose() closes the underlying fd and
 525         * stream buffering only can be changed before first I/O operation
 526         * on it.
 527         */
 528        duped = dup(helper->out);
 529        if (duped < 0)
 530                die_errno("Can't dup helper output fd");
 531        input = xfdopen(duped, "r");
 532        setvbuf(input, NULL, _IONBF, 0);
 533
 534        /*
 535         * Handle --upload-pack and friends. This is fire and forget...
 536         * just warn if it fails.
 537         */
 538        if (strcmp(name, exec)) {
 539                r = set_helper_option(transport, "servpath", exec);
 540                if (r > 0)
 541                        warning("Setting remote service path not supported by protocol.");
 542                else if (r < 0)
 543                        warning("Invalid remote service path.");
 544        }
 545
 546        if (data->connect)
 547                strbuf_addf(&cmdbuf, "connect %s\n", name);
 548        else
 549                goto exit;
 550
 551        sendline(data, &cmdbuf);
 552        if (recvline_fh(input, &cmdbuf, name))
 553                exit(128);
 554
 555        if (!strcmp(cmdbuf.buf, "")) {
 556                data->no_disconnect_req = 1;
 557                if (debug)
 558                        fprintf(stderr, "Debug: Smart transport connection "
 559                                "ready.\n");
 560                ret = 1;
 561        } else if (!strcmp(cmdbuf.buf, "fallback")) {
 562                if (debug)
 563                        fprintf(stderr, "Debug: Falling back to dumb "
 564                                "transport.\n");
 565        } else
 566                die("Unknown response to connect: %s",
 567                        cmdbuf.buf);
 568
 569exit:
 570        fclose(input);
 571        return ret;
 572}
 573
 574static int process_connect(struct transport *transport,
 575                                     int for_push)
 576{
 577        struct helper_data *data = transport->data;
 578        const char *name;
 579        const char *exec;
 580
 581        name = for_push ? "git-receive-pack" : "git-upload-pack";
 582        if (for_push)
 583                exec = data->transport_options.receivepack;
 584        else
 585                exec = data->transport_options.uploadpack;
 586
 587        return process_connect_service(transport, name, exec);
 588}
 589
 590static int connect_helper(struct transport *transport, const char *name,
 591                   const char *exec, int fd[2])
 592{
 593        struct helper_data *data = transport->data;
 594
 595        /* Get_helper so connect is inited. */
 596        get_helper(transport);
 597        if (!data->connect)
 598                die("Operation not supported by protocol.");
 599
 600        if (!process_connect_service(transport, name, exec))
 601                die("Can't connect to subservice %s.", name);
 602
 603        fd[0] = data->helper->out;
 604        fd[1] = data->helper->in;
 605        return 0;
 606}
 607
 608static int fetch(struct transport *transport,
 609                 int nr_heads, struct ref **to_fetch)
 610{
 611        struct helper_data *data = transport->data;
 612        int i, count;
 613
 614        if (process_connect(transport, 0)) {
 615                do_take_over(transport);
 616                return transport->fetch(transport, nr_heads, to_fetch);
 617        }
 618
 619        count = 0;
 620        for (i = 0; i < nr_heads; i++)
 621                if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
 622                        count++;
 623
 624        if (!count)
 625                return 0;
 626
 627        if (data->fetch)
 628                return fetch_with_fetch(transport, nr_heads, to_fetch);
 629
 630        if (data->import)
 631                return fetch_with_import(transport, nr_heads, to_fetch);
 632
 633        return -1;
 634}
 635
 636static int push_update_ref_status(struct strbuf *buf,
 637                                   struct ref **ref,
 638                                   struct ref *remote_refs)
 639{
 640        char *refname, *msg;
 641        int status, forced = 0;
 642
 643        if (starts_with(buf->buf, "ok ")) {
 644                status = REF_STATUS_OK;
 645                refname = buf->buf + 3;
 646        } else if (starts_with(buf->buf, "error ")) {
 647                status = REF_STATUS_REMOTE_REJECT;
 648                refname = buf->buf + 6;
 649        } else
 650                die("expected ok/error, helper said '%s'", buf->buf);
 651
 652        msg = strchr(refname, ' ');
 653        if (msg) {
 654                struct strbuf msg_buf = STRBUF_INIT;
 655                const char *end;
 656
 657                *msg++ = '\0';
 658                if (!unquote_c_style(&msg_buf, msg, &end))
 659                        msg = strbuf_detach(&msg_buf, NULL);
 660                else
 661                        msg = xstrdup(msg);
 662                strbuf_release(&msg_buf);
 663
 664                if (!strcmp(msg, "no match")) {
 665                        status = REF_STATUS_NONE;
 666                        free(msg);
 667                        msg = NULL;
 668                }
 669                else if (!strcmp(msg, "up to date")) {
 670                        status = REF_STATUS_UPTODATE;
 671                        free(msg);
 672                        msg = NULL;
 673                }
 674                else if (!strcmp(msg, "non-fast forward")) {
 675                        status = REF_STATUS_REJECT_NONFASTFORWARD;
 676                        free(msg);
 677                        msg = NULL;
 678                }
 679                else if (!strcmp(msg, "already exists")) {
 680                        status = REF_STATUS_REJECT_ALREADY_EXISTS;
 681                        free(msg);
 682                        msg = NULL;
 683                }
 684                else if (!strcmp(msg, "fetch first")) {
 685                        status = REF_STATUS_REJECT_FETCH_FIRST;
 686                        free(msg);
 687                        msg = NULL;
 688                }
 689                else if (!strcmp(msg, "needs force")) {
 690                        status = REF_STATUS_REJECT_NEEDS_FORCE;
 691                        free(msg);
 692                        msg = NULL;
 693                }
 694                else if (!strcmp(msg, "stale info")) {
 695                        status = REF_STATUS_REJECT_STALE;
 696                        free(msg);
 697                        msg = NULL;
 698                }
 699                else if (!strcmp(msg, "forced update")) {
 700                        forced = 1;
 701                        free(msg);
 702                        msg = NULL;
 703                }
 704        }
 705
 706        if (*ref)
 707                *ref = find_ref_by_name(*ref, refname);
 708        if (!*ref)
 709                *ref = find_ref_by_name(remote_refs, refname);
 710        if (!*ref) {
 711                warning("helper reported unexpected status of %s", refname);
 712                return 1;
 713        }
 714
 715        if ((*ref)->status != REF_STATUS_NONE) {
 716                /*
 717                 * Earlier, the ref was marked not to be pushed, so ignore the ref
 718                 * status reported by the remote helper if the latter is 'no match'.
 719                 */
 720                if (status == REF_STATUS_NONE)
 721                        return 1;
 722        }
 723
 724        (*ref)->status = status;
 725        (*ref)->forced_update |= forced;
 726        (*ref)->remote_status = msg;
 727        return !(status == REF_STATUS_OK);
 728}
 729
 730static int push_update_refs_status(struct helper_data *data,
 731                                    struct ref *remote_refs,
 732                                    int flags)
 733{
 734        struct strbuf buf = STRBUF_INIT;
 735        struct ref *ref = remote_refs;
 736        int ret = 0;
 737
 738        for (;;) {
 739                char *private;
 740
 741                if (recvline(data, &buf)) {
 742                        ret = 1;
 743                        break;
 744                }
 745
 746                if (!buf.len)
 747                        break;
 748
 749                if (push_update_ref_status(&buf, &ref, remote_refs))
 750                        continue;
 751
 752                if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
 753                        continue;
 754
 755                /* propagate back the update to the remote namespace */
 756                private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 757                if (!private)
 758                        continue;
 759                update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
 760                free(private);
 761        }
 762        strbuf_release(&buf);
 763        return ret;
 764}
 765
 766static int push_refs_with_push(struct transport *transport,
 767                               struct ref *remote_refs, int flags)
 768{
 769        int force_all = flags & TRANSPORT_PUSH_FORCE;
 770        int mirror = flags & TRANSPORT_PUSH_MIRROR;
 771        struct helper_data *data = transport->data;
 772        struct strbuf buf = STRBUF_INIT;
 773        struct ref *ref;
 774        struct string_list cas_options = STRING_LIST_INIT_DUP;
 775        struct string_list_item *cas_option;
 776
 777        get_helper(transport);
 778        if (!data->push)
 779                return 1;
 780
 781        for (ref = remote_refs; ref; ref = ref->next) {
 782                if (!ref->peer_ref && !mirror)
 783                        continue;
 784
 785                /* Check for statuses set by set_ref_status_for_push() */
 786                switch (ref->status) {
 787                case REF_STATUS_REJECT_NONFASTFORWARD:
 788                case REF_STATUS_REJECT_STALE:
 789                case REF_STATUS_REJECT_ALREADY_EXISTS:
 790                case REF_STATUS_UPTODATE:
 791                        continue;
 792                default:
 793                        ; /* do nothing */
 794                }
 795
 796                if (force_all)
 797                        ref->force = 1;
 798
 799                strbuf_addstr(&buf, "push ");
 800                if (!ref->deletion) {
 801                        if (ref->force)
 802                                strbuf_addch(&buf, '+');
 803                        if (ref->peer_ref)
 804                                strbuf_addstr(&buf, ref->peer_ref->name);
 805                        else
 806                                strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
 807                }
 808                strbuf_addch(&buf, ':');
 809                strbuf_addstr(&buf, ref->name);
 810                strbuf_addch(&buf, '\n');
 811
 812                /*
 813                 * The "--force-with-lease" options without explicit
 814                 * values to expect have already been expanded into
 815                 * the ref->old_sha1_expect[] field; we can ignore
 816                 * transport->smart_options->cas altogether and instead
 817                 * can enumerate them from the refs.
 818                 */
 819                if (ref->expect_old_sha1) {
 820                        struct strbuf cas = STRBUF_INIT;
 821                        strbuf_addf(&cas, "%s:%s",
 822                                    ref->name, sha1_to_hex(ref->old_sha1_expect));
 823                        string_list_append(&cas_options, strbuf_detach(&cas, NULL));
 824                }
 825        }
 826        if (buf.len == 0) {
 827                string_list_clear(&cas_options, 0);
 828                return 0;
 829        }
 830
 831        standard_options(transport);
 832        for_each_string_list_item(cas_option, &cas_options)
 833                set_helper_option(transport, "cas", cas_option->string);
 834
 835        if (flags & TRANSPORT_PUSH_DRY_RUN) {
 836                if (set_helper_option(transport, "dry-run", "true") != 0)
 837                        die("helper %s does not support dry-run", data->name);
 838        }
 839
 840        strbuf_addch(&buf, '\n');
 841        sendline(data, &buf);
 842        strbuf_release(&buf);
 843
 844        return push_update_refs_status(data, remote_refs, flags);
 845}
 846
 847static int push_refs_with_export(struct transport *transport,
 848                struct ref *remote_refs, int flags)
 849{
 850        struct ref *ref;
 851        struct child_process *helper, exporter;
 852        struct helper_data *data = transport->data;
 853        struct string_list revlist_args = STRING_LIST_INIT_DUP;
 854        struct strbuf buf = STRBUF_INIT;
 855
 856        if (!data->refspecs)
 857                die("remote-helper doesn't support push; refspec needed");
 858
 859        if (flags & TRANSPORT_PUSH_DRY_RUN) {
 860                if (set_helper_option(transport, "dry-run", "true") != 0)
 861                        die("helper %s does not support dry-run", data->name);
 862        }
 863
 864        if (flags & TRANSPORT_PUSH_FORCE) {
 865                if (set_helper_option(transport, "force", "true") != 0)
 866                        warning("helper %s does not support 'force'", data->name);
 867        }
 868
 869        helper = get_helper(transport);
 870
 871        write_constant(helper->in, "export\n");
 872
 873        for (ref = remote_refs; ref; ref = ref->next) {
 874                char *private;
 875                unsigned char sha1[20];
 876
 877                private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 878                if (private && !get_sha1(private, sha1)) {
 879                        strbuf_addf(&buf, "^%s", private);
 880                        string_list_append(&revlist_args, strbuf_detach(&buf, NULL));
 881                        hashcpy(ref->old_sha1, sha1);
 882                }
 883                free(private);
 884
 885                if (ref->peer_ref) {
 886                        if (strcmp(ref->name, ref->peer_ref->name)) {
 887                                if (!ref->deletion) {
 888                                        const char *name;
 889                                        int flag;
 890
 891                                        /* Follow symbolic refs (mainly for HEAD). */
 892                                        name = resolve_ref_unsafe(ref->peer_ref->name, sha1, 1, &flag);
 893                                        if (!name || !(flag & REF_ISSYMREF))
 894                                                name = ref->peer_ref->name;
 895
 896                                        strbuf_addf(&buf, "%s:%s", name, ref->name);
 897                                } else
 898                                        strbuf_addf(&buf, ":%s", ref->name);
 899
 900                                string_list_append(&revlist_args, "--refspec");
 901                                string_list_append(&revlist_args, buf.buf);
 902                                strbuf_release(&buf);
 903                        }
 904                        if (!ref->deletion)
 905                                string_list_append(&revlist_args, ref->peer_ref->name);
 906                }
 907        }
 908
 909        if (get_exporter(transport, &exporter, &revlist_args))
 910                die("Couldn't run fast-export");
 911
 912        string_list_clear(&revlist_args, 1);
 913
 914        if (finish_command(&exporter))
 915                die("Error while running fast-export");
 916        if (push_update_refs_status(data, remote_refs, flags))
 917                return 1;
 918
 919        if (data->export_marks) {
 920                strbuf_addf(&buf, "%s.tmp", data->export_marks);
 921                rename(buf.buf, data->export_marks);
 922                strbuf_release(&buf);
 923        }
 924
 925        return 0;
 926}
 927
 928static int push_refs(struct transport *transport,
 929                struct ref *remote_refs, int flags)
 930{
 931        struct helper_data *data = transport->data;
 932
 933        if (process_connect(transport, 1)) {
 934                do_take_over(transport);
 935                return transport->push_refs(transport, remote_refs, flags);
 936        }
 937
 938        if (!remote_refs) {
 939                fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 940                        "Perhaps you should specify a branch such as 'master'.\n");
 941                return 0;
 942        }
 943
 944        if (data->push)
 945                return push_refs_with_push(transport, remote_refs, flags);
 946
 947        if (data->export)
 948                return push_refs_with_export(transport, remote_refs, flags);
 949
 950        return -1;
 951}
 952
 953
 954static int has_attribute(const char *attrs, const char *attr) {
 955        int len;
 956        if (!attrs)
 957                return 0;
 958
 959        len = strlen(attr);
 960        for (;;) {
 961                const char *space = strchrnul(attrs, ' ');
 962                if (len == space - attrs && !strncmp(attrs, attr, len))
 963                        return 1;
 964                if (!*space)
 965                        return 0;
 966                attrs = space + 1;
 967        }
 968}
 969
 970static struct ref *get_refs_list(struct transport *transport, int for_push)
 971{
 972        struct helper_data *data = transport->data;
 973        struct child_process *helper;
 974        struct ref *ret = NULL;
 975        struct ref **tail = &ret;
 976        struct ref *posn;
 977        struct strbuf buf = STRBUF_INIT;
 978
 979        helper = get_helper(transport);
 980
 981        if (process_connect(transport, for_push)) {
 982                do_take_over(transport);
 983                return transport->get_refs_list(transport, for_push);
 984        }
 985
 986        if (data->push && for_push)
 987                write_str_in_full(helper->in, "list for-push\n");
 988        else
 989                write_str_in_full(helper->in, "list\n");
 990
 991        while (1) {
 992                char *eov, *eon;
 993                if (recvline(data, &buf))
 994                        exit(128);
 995
 996                if (!*buf.buf)
 997                        break;
 998
 999                eov = strchr(buf.buf, ' ');
1000                if (!eov)
1001                        die("Malformed response in ref list: %s", buf.buf);
1002                eon = strchr(eov + 1, ' ');
1003                *eov = '\0';
1004                if (eon)
1005                        *eon = '\0';
1006                *tail = alloc_ref(eov + 1);
1007                if (buf.buf[0] == '@')
1008                        (*tail)->symref = xstrdup(buf.buf + 1);
1009                else if (buf.buf[0] != '?')
1010                        get_sha1_hex(buf.buf, (*tail)->old_sha1);
1011                if (eon) {
1012                        if (has_attribute(eon + 1, "unchanged")) {
1013                                (*tail)->status |= REF_STATUS_UPTODATE;
1014                                read_ref((*tail)->name, (*tail)->old_sha1);
1015                        }
1016                }
1017                tail = &((*tail)->next);
1018        }
1019        if (debug)
1020                fprintf(stderr, "Debug: Read ref listing.\n");
1021        strbuf_release(&buf);
1022
1023        for (posn = ret; posn; posn = posn->next)
1024                resolve_remote_symref(posn, ret);
1025
1026        return ret;
1027}
1028
1029int transport_helper_init(struct transport *transport, const char *name)
1030{
1031        struct helper_data *data = xcalloc(1, sizeof(*data));
1032        data->name = name;
1033
1034        if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
1035                debug = 1;
1036
1037        transport->data = data;
1038        transport->set_option = set_helper_option;
1039        transport->get_refs_list = get_refs_list;
1040        transport->fetch = fetch;
1041        transport->push_refs = push_refs;
1042        transport->disconnect = release_helper;
1043        transport->connect = connect_helper;
1044        transport->smart_options = &(data->transport_options);
1045        return 0;
1046}
1047
1048/*
1049 * Linux pipes can buffer 65536 bytes at once (and most platforms can
1050 * buffer less), so attempt reads and writes with up to that size.
1051 */
1052#define BUFFERSIZE 65536
1053/* This should be enough to hold debugging message. */
1054#define PBUFFERSIZE 8192
1055
1056/* Print bidirectional transfer loop debug message. */
1057__attribute__((format (printf, 1, 2)))
1058static void transfer_debug(const char *fmt, ...)
1059{
1060        va_list args;
1061        char msgbuf[PBUFFERSIZE];
1062        static int debug_enabled = -1;
1063
1064        if (debug_enabled < 0)
1065                debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
1066        if (!debug_enabled)
1067                return;
1068
1069        va_start(args, fmt);
1070        vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
1071        va_end(args);
1072        fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
1073}
1074
1075/* Stream state: More data may be coming in this direction. */
1076#define SSTATE_TRANSFERING 0
1077/*
1078 * Stream state: No more data coming in this direction, flushing rest of
1079 * data.
1080 */
1081#define SSTATE_FLUSHING 1
1082/* Stream state: Transfer in this direction finished. */
1083#define SSTATE_FINISHED 2
1084
1085#define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERING)
1086#define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
1087#define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)
1088
1089/* Unidirectional transfer. */
1090struct unidirectional_transfer {
1091        /* Source */
1092        int src;
1093        /* Destination */
1094        int dest;
1095        /* Is source socket? */
1096        int src_is_sock;
1097        /* Is destination socket? */
1098        int dest_is_sock;
1099        /* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
1100        int state;
1101        /* Buffer. */
1102        char buf[BUFFERSIZE];
1103        /* Buffer used. */
1104        size_t bufuse;
1105        /* Name of source. */
1106        const char *src_name;
1107        /* Name of destination. */
1108        const char *dest_name;
1109};
1110
1111/* Closes the target (for writing) if transfer has finished. */
1112static void udt_close_if_finished(struct unidirectional_transfer *t)
1113{
1114        if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
1115                t->state = SSTATE_FINISHED;
1116                if (t->dest_is_sock)
1117                        shutdown(t->dest, SHUT_WR);
1118                else
1119                        close(t->dest);
1120                transfer_debug("Closed %s.", t->dest_name);
1121        }
1122}
1123
1124/*
1125 * Tries to read read data from source into buffer. If buffer is full,
1126 * no data is read. Returns 0 on success, -1 on error.
1127 */
1128static int udt_do_read(struct unidirectional_transfer *t)
1129{
1130        ssize_t bytes;
1131
1132        if (t->bufuse == BUFFERSIZE)
1133                return 0;       /* No space for more. */
1134
1135        transfer_debug("%s is readable", t->src_name);
1136        bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
1137        if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
1138                errno != EINTR) {
1139                error("read(%s) failed: %s", t->src_name, strerror(errno));
1140                return -1;
1141        } else if (bytes == 0) {
1142                transfer_debug("%s EOF (with %i bytes in buffer)",
1143                        t->src_name, (int)t->bufuse);
1144                t->state = SSTATE_FLUSHING;
1145        } else if (bytes > 0) {
1146                t->bufuse += bytes;
1147                transfer_debug("Read %i bytes from %s (buffer now at %i)",
1148                        (int)bytes, t->src_name, (int)t->bufuse);
1149        }
1150        return 0;
1151}
1152
1153/* Tries to write data from buffer into destination. If buffer is empty,
1154 * no data is written. Returns 0 on success, -1 on error.
1155 */
1156static int udt_do_write(struct unidirectional_transfer *t)
1157{
1158        ssize_t bytes;
1159
1160        if (t->bufuse == 0)
1161                return 0;       /* Nothing to write. */
1162
1163        transfer_debug("%s is writable", t->dest_name);
1164        bytes = xwrite(t->dest, t->buf, t->bufuse);
1165        if (bytes < 0 && errno != EWOULDBLOCK) {
1166                error("write(%s) failed: %s", t->dest_name, strerror(errno));
1167                return -1;
1168        } else if (bytes > 0) {
1169                t->bufuse -= bytes;
1170                if (t->bufuse)
1171                        memmove(t->buf, t->buf + bytes, t->bufuse);
1172                transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
1173                        (int)bytes, t->dest_name, (int)t->bufuse);
1174        }
1175        return 0;
1176}
1177
1178
1179/* State of bidirectional transfer loop. */
1180struct bidirectional_transfer_state {
1181        /* Direction from program to git. */
1182        struct unidirectional_transfer ptg;
1183        /* Direction from git to program. */
1184        struct unidirectional_transfer gtp;
1185};
1186
1187static void *udt_copy_task_routine(void *udt)
1188{
1189        struct unidirectional_transfer *t = (struct unidirectional_transfer *)udt;
1190        while (t->state != SSTATE_FINISHED) {
1191                if (STATE_NEEDS_READING(t->state))
1192                        if (udt_do_read(t))
1193                                return NULL;
1194                if (STATE_NEEDS_WRITING(t->state))
1195                        if (udt_do_write(t))
1196                                return NULL;
1197                if (STATE_NEEDS_CLOSING(t->state))
1198                        udt_close_if_finished(t);
1199        }
1200        return udt;     /* Just some non-NULL value. */
1201}
1202
1203#ifndef NO_PTHREADS
1204
1205/*
1206 * Join thread, with appropriate errors on failure. Name is name for the
1207 * thread (for error messages). Returns 0 on success, 1 on failure.
1208 */
1209static int tloop_join(pthread_t thread, const char *name)
1210{
1211        int err;
1212        void *tret;
1213        err = pthread_join(thread, &tret);
1214        if (!tret) {
1215                error("%s thread failed", name);
1216                return 1;
1217        }
1218        if (err) {
1219                error("%s thread failed to join: %s", name, strerror(err));
1220                return 1;
1221        }
1222        return 0;
1223}
1224
1225/*
1226 * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1227 * -1 on failure.
1228 */
1229static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1230{
1231        pthread_t gtp_thread;
1232        pthread_t ptg_thread;
1233        int err;
1234        int ret = 0;
1235        err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
1236                &s->gtp);
1237        if (err)
1238                die("Can't start thread for copying data: %s", strerror(err));
1239        err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
1240                &s->ptg);
1241        if (err)
1242                die("Can't start thread for copying data: %s", strerror(err));
1243
1244        ret |= tloop_join(gtp_thread, "Git to program copy");
1245        ret |= tloop_join(ptg_thread, "Program to git copy");
1246        return ret;
1247}
1248#else
1249
1250/* Close the source and target (for writing) for transfer. */
1251static void udt_kill_transfer(struct unidirectional_transfer *t)
1252{
1253        t->state = SSTATE_FINISHED;
1254        /*
1255         * Socket read end left open isn't a disaster if nobody
1256         * attempts to read from it (mingw compat headers do not
1257         * have SHUT_RD)...
1258         *
1259         * We can't fully close the socket since otherwise gtp
1260         * task would first close the socket it sends data to
1261         * while closing the ptg file descriptors.
1262         */
1263        if (!t->src_is_sock)
1264                close(t->src);
1265        if (t->dest_is_sock)
1266                shutdown(t->dest, SHUT_WR);
1267        else
1268                close(t->dest);
1269}
1270
1271/*
1272 * Join process, with appropriate errors on failure. Name is name for the
1273 * process (for error messages). Returns 0 on success, 1 on failure.
1274 */
1275static int tloop_join(pid_t pid, const char *name)
1276{
1277        int tret;
1278        if (waitpid(pid, &tret, 0) < 0) {
1279                error("%s process failed to wait: %s", name, strerror(errno));
1280                return 1;
1281        }
1282        if (!WIFEXITED(tret) || WEXITSTATUS(tret)) {
1283                error("%s process failed", name);
1284                return 1;
1285        }
1286        return 0;
1287}
1288
1289/*
1290 * Spawn the transfer tasks and then wait for them. Returns 0 on success,
1291 * -1 on failure.
1292 */
1293static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
1294{
1295        pid_t pid1, pid2;
1296        int ret = 0;
1297
1298        /* Fork thread #1: git to program. */
1299        pid1 = fork();
1300        if (pid1 < 0)
1301                die_errno("Can't start thread for copying data");
1302        else if (pid1 == 0) {
1303                udt_kill_transfer(&s->ptg);
1304                exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
1305        }
1306
1307        /* Fork thread #2: program to git. */
1308        pid2 = fork();
1309        if (pid2 < 0)
1310                die_errno("Can't start thread for copying data");
1311        else if (pid2 == 0) {
1312                udt_kill_transfer(&s->gtp);
1313                exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
1314        }
1315
1316        /*
1317         * Close both streams in parent as to not interfere with
1318         * end of file detection and wait for both tasks to finish.
1319         */
1320        udt_kill_transfer(&s->gtp);
1321        udt_kill_transfer(&s->ptg);
1322        ret |= tloop_join(pid1, "Git to program copy");
1323        ret |= tloop_join(pid2, "Program to git copy");
1324        return ret;
1325}
1326#endif
1327
1328/*
1329 * Copies data from stdin to output and from input to stdout simultaneously.
1330 * Additionally filtering through given filter. If filter is NULL, uses
1331 * identity filter.
1332 */
1333int bidirectional_transfer_loop(int input, int output)
1334{
1335        struct bidirectional_transfer_state state;
1336
1337        /* Fill the state fields. */
1338        state.ptg.src = input;
1339        state.ptg.dest = 1;
1340        state.ptg.src_is_sock = (input == output);
1341        state.ptg.dest_is_sock = 0;
1342        state.ptg.state = SSTATE_TRANSFERING;
1343        state.ptg.bufuse = 0;
1344        state.ptg.src_name = "remote input";
1345        state.ptg.dest_name = "stdout";
1346
1347        state.gtp.src = 0;
1348        state.gtp.dest = output;
1349        state.gtp.src_is_sock = 0;
1350        state.gtp.dest_is_sock = (input == output);
1351        state.gtp.state = SSTATE_TRANSFERING;
1352        state.gtp.bufuse = 0;
1353        state.gtp.src_name = "stdin";
1354        state.gtp.dest_name = "remote output";
1355
1356        return tloop_spawnwait_tasks(&state);
1357}