upload-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "sideband.h"
   5 #include "tag.h"
   6 #include "object.h"
   7 #include "commit.h"
   8 #include "exec_cmd.h"
   9 #include "diff.h"
  10 #include "revision.h"
  11 #include "list-objects.h"
  12
  13 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  14
  15 /* bits #0..7 in revision.h, #8..10 in commit.c */
  16 #define THEY_HAVE       (1u << 11)
  17 #define OUR_REF         (1u << 12)
  18 #define WANTED          (1u << 13)
  19 #define COMMON_KNOWN    (1u << 14)
  20 #define REACHABLE       (1u << 15)
  21
  22 #define SHALLOW         (1u << 16)
  23 #define NOT_SHALLOW     (1u << 17)
  24 #define CLIENT_SHALLOW  (1u << 18)
  25
  26 static unsigned long oldest_have;
  27
  28 static int multi_ack, nr_our_refs;
  29 static int use_thin_pack, use_ofs_delta, no_progress;
  30 static struct object_array have_obj;
  31 static struct object_array want_obj;
  32 static unsigned int timeout;
  33 /* 0 for no sideband,
  34  * otherwise maximum packet size (up to 65520 bytes).
  35  */
  36 static int use_sideband;
  37
  38 static void reset_timeout(void)
  39 {
  40         alarm(timeout);
  41 }
  42
  43 static int strip(char *line, int len)
  44 {
  45         if (len && line[len-1] == '\n')
  46                 line[--len] = 0;
  47         return len;
  48 }
  49
  50 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  51 {
  52         if (use_sideband)
  53                 return send_sideband(1, fd, data, sz, use_sideband);
  54         if (fd == 3)
  55                 /* emergency quit */
  56                 fd = 2;
  57         if (fd == 2) {
  58                 /* XXX: are we happy to lose stuff here? */
  59                 xwrite(fd, data, sz);
  60                 return sz;
  61         }
  62         return safe_write(fd, data, sz);
  63 }
  64
  65 FILE *pack_pipe = NULL;
  66 static void show_commit(struct commit *commit)
  67 {
  68         if (commit->object.flags & BOUNDARY)
  69                 fputc('-', pack_pipe);
  70         if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
  71                 die("broken output pipe");
  72         fputc('\n', pack_pipe);
  73         fflush(pack_pipe);
  74         free(commit->buffer);
  75         commit->buffer = NULL;
  76 }
  77
  78 static void show_object(struct object_array_entry *p)
  79 {
  80         /* An object with name "foo\n0000000..." can be used to
  81          * confuse downstream git-pack-objects very badly.
  82          */
  83         const char *ep = strchr(p->name, '\n');
  84         if (ep) {
  85                 fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(p->item->sha1),
  86                        (int) (ep - p->name),
  87                        p->name);
  88         }
  89         else
  90                 fprintf(pack_pipe, "%s %s\n",
  91                                 sha1_to_hex(p->item->sha1), p->name);
  92 }
  93
  94 static void show_edge(struct commit *commit)
  95 {
  96         fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
  97 }
  98
  99 static void create_pack_file(void)
 100 {
 101         /* Pipes between rev-list to pack-objects, pack-objects to us
 102          * and pack-objects error stream for progress bar.
 103          */
 104         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
 105         pid_t pid_rev_list, pid_pack_objects;
 106         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
 107         char data[8193], progress[128];
 108         char abort_msg[] = "aborting due to possible repository "
 109                 "corruption on the remote side.";
 110         int buffered = -1;
 111
 112         if (pipe(lp_pipe) < 0)
 113                 die("git-upload-pack: unable to create pipe");
 114         pid_rev_list = fork();
 115         if (pid_rev_list < 0)
 116                 die("git-upload-pack: unable to fork git-rev-list");
 117
 118         if (!pid_rev_list) {
 119                 int i;
 120                 struct rev_info revs;
 121
 122                 pack_pipe = fdopen(lp_pipe[1], "w");
 123
 124                 if (create_full_pack)
 125                         use_thin_pack = 0; /* no point doing it */
 126                 init_revisions(&revs, NULL);
 127                 revs.tag_objects = 1;
 128                 revs.tree_objects = 1;
 129                 revs.blob_objects = 1;
 130                 if (use_thin_pack)
 131                         revs.edge_hint = 1;
 132
 133                 if (create_full_pack) {
 134                         const char *args[] = {"rev-list", "--all", NULL};
 135                         setup_revisions(2, args, &revs, NULL);
 136                 } else {
 137                         for (i = 0; i < want_obj.nr; i++) {
 138                                 struct object *o = want_obj.objects[i].item;
 139                                 /* why??? */
 140                                 o->flags &= ~UNINTERESTING;
 141                                 add_pending_object(&revs, o, NULL);
 142                         }
 143                         for (i = 0; i < have_obj.nr; i++) {
 144                                 struct object *o = have_obj.objects[i].item;
 145                                 o->flags |= UNINTERESTING;
 146                                 add_pending_object(&revs, o, NULL);
 147                         }
 148                         setup_revisions(0, NULL, &revs, NULL);
 149                 }
 150                 prepare_revision_walk(&revs);
 151                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
 152                 traverse_commit_list(&revs, show_commit, show_object);
 153                 exit(0);
 154         }
 155
 156         if (pipe(pu_pipe) < 0)
 157                 die("git-upload-pack: unable to create pipe");
 158         if (pipe(pe_pipe) < 0)
 159                 die("git-upload-pack: unable to create pipe");
 160         pid_pack_objects = fork();
 161         if (pid_pack_objects < 0) {
 162                 /* daemon sets things up to ignore TERM */
 163                 kill(pid_rev_list, SIGKILL);
 164                 die("git-upload-pack: unable to fork git-pack-objects");
 165         }
 166         if (!pid_pack_objects) {
 167                 const char *argv[10];
 168                 int i = 0;
 169
 170                 dup2(lp_pipe[0], 0);
 171                 dup2(pu_pipe[1], 1);
 172                 dup2(pe_pipe[1], 2);
 173
 174                 close(lp_pipe[0]);
 175                 close(lp_pipe[1]);
 176                 close(pu_pipe[0]);
 177                 close(pu_pipe[1]);
 178                 close(pe_pipe[0]);
 179                 close(pe_pipe[1]);
 180
 181                 argv[i++] = "pack-objects";
 182                 argv[i++] = "--stdout";
 183                 if (!no_progress)
 184                         argv[i++] = "--progress";
 185                 if (use_ofs_delta)
 186                         argv[i++] = "--delta-base-offset";
 187                 argv[i++] = NULL;
 188
 189                 execv_git_cmd(argv);
 190                 kill(pid_rev_list, SIGKILL);
 191                 die("git-upload-pack: unable to exec git-pack-objects");
 192         }
 193
 194         close(lp_pipe[0]);
 195         close(lp_pipe[1]);
 196
 197         /* We read from pe_pipe[0] to capture stderr output for
 198          * progress bar, and pu_pipe[0] to capture the pack data.
 199          */
 200         close(pe_pipe[1]);
 201         close(pu_pipe[1]);
 202
 203         while (1) {
 204                 const char *who;
 205                 struct pollfd pfd[2];
 206                 pid_t pid;
 207                 int status;
 208                 ssize_t sz;
 209                 int pe, pu, pollsize;
 210
 211                 reset_timeout();
 212
 213                 pollsize = 0;
 214                 pe = pu = -1;
 215
 216                 if (0 <= pu_pipe[0]) {
 217                         pfd[pollsize].fd = pu_pipe[0];
 218                         pfd[pollsize].events = POLLIN;
 219                         pu = pollsize;
 220                         pollsize++;
 221                 }
 222                 if (0 <= pe_pipe[0]) {
 223                         pfd[pollsize].fd = pe_pipe[0];
 224                         pfd[pollsize].events = POLLIN;
 225                         pe = pollsize;
 226                         pollsize++;
 227                 }
 228
 229                 if (pollsize) {
 230                         if (poll(pfd, pollsize, -1) < 0) {
 231                                 if (errno != EINTR) {
 232                                         error("poll failed, resuming: %s",
 233                                               strerror(errno));
 234                                         sleep(1);
 235                                 }
 236                                 continue;
 237                         }
 238                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 239                                 /* Data ready; we keep the last byte
 240                                  * to ourselves in case we detect
 241                                  * broken rev-list, so that we can
 242                                  * leave the stream corrupted.  This
 243                                  * is unfortunate -- unpack-objects
 244                                  * would happily accept a valid pack
 245                                  * data with trailing garbage, so
 246                                  * appending garbage after we pass all
 247                                  * the pack data is not good enough to
 248                                  * signal breakage to downstream.
 249                                  */
 250                                 char *cp = data;
 251                                 ssize_t outsz = 0;
 252                                 if (0 <= buffered) {
 253                                         *cp++ = buffered;
 254                                         outsz++;
 255                                 }
 256                                 sz = xread(pu_pipe[0], cp,
 257                                           sizeof(data) - outsz);
 258                                 if (0 < sz)
 259                                                 ;
 260                                 else if (sz == 0) {
 261                                         close(pu_pipe[0]);
 262                                         pu_pipe[0] = -1;
 263                                 }
 264                                 else
 265                                         goto fail;
 266                                 sz += outsz;
 267                                 if (1 < sz) {
 268                                         buffered = data[sz-1] & 0xFF;
 269                                         sz--;
 270                                 }
 271                                 else
 272                                         buffered = -1;
 273                                 sz = send_client_data(1, data, sz);
 274                                 if (sz < 0)
 275                                         goto fail;
 276                         }
 277                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 278                                 /* Status ready; we ship that in the side-band
 279                                  * or dump to the standard error.
 280                                  */
 281                                 sz = xread(pe_pipe[0], progress,
 282                                           sizeof(progress));
 283                                 if (0 < sz)
 284                                         send_client_data(2, progress, sz);
 285                                 else if (sz == 0) {
 286                                         close(pe_pipe[0]);
 287                                         pe_pipe[0] = -1;
 288                                 }
 289                                 else
 290                                         goto fail;
 291                         }
 292                 }
 293
 294                 /* See if the children are still there */
 295                 if (pid_rev_list || pid_pack_objects) {
 296                         pid = waitpid(-1, &status, WNOHANG);
 297                         if (!pid)
 298                                 continue;
 299                         who = ((pid == pid_rev_list) ? "git-rev-list" :
 300                                (pid == pid_pack_objects) ? "git-pack-objects" :
 301                                NULL);
 302                         if (!who) {
 303                                 if (pid < 0) {
 304                                         error("git-upload-pack: %s",
 305                                               strerror(errno));
 306                                         goto fail;
 307                                 }
 308                                 error("git-upload-pack: we weren't "
 309                                       "waiting for %d", pid);
 310                                 continue;
 311                         }
 312                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 313                                 error("git-upload-pack: %s died with error.",
 314                                       who);
 315                                 goto fail;
 316                         }
 317                         if (pid == pid_rev_list)
 318                                 pid_rev_list = 0;
 319                         if (pid == pid_pack_objects)
 320                                 pid_pack_objects = 0;
 321                         if (pid_rev_list || pid_pack_objects)
 322                                 continue;
 323                 }
 324
 325                 /* both died happily */
 326                 if (pollsize)
 327                         continue;
 328
 329                 /* flush the data */
 330                 if (0 <= buffered) {
 331                         data[0] = buffered;
 332                         sz = send_client_data(1, data, 1);
 333                         if (sz < 0)
 334                                 goto fail;
 335                         fprintf(stderr, "flushed.\n");
 336                 }
 337                 if (use_sideband)
 338                         packet_flush(1);
 339                 return;
 340         }
 341  fail:
 342         if (pid_pack_objects)
 343                 kill(pid_pack_objects, SIGKILL);
 344         if (pid_rev_list)
 345                 kill(pid_rev_list, SIGKILL);
 346         send_client_data(3, abort_msg, sizeof(abort_msg));
 347         die("git-upload-pack: %s", abort_msg);
 348 }
 349
 350 static int got_sha1(char *hex, unsigned char *sha1)
 351 {
 352         struct object *o;
 353         int we_knew_they_have = 0;
 354
 355         if (get_sha1_hex(hex, sha1))
 356                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 357         if (!has_sha1_file(sha1))
 358                 return -1;
 359
 360         o = lookup_object(sha1);
 361         if (!(o && o->parsed))
 362                 o = parse_object(sha1);
 363         if (!o)
 364                 die("oops (%s)", sha1_to_hex(sha1));
 365         if (o->type == OBJ_COMMIT) {
 366                 struct commit_list *parents;
 367                 struct commit *commit = (struct commit *)o;
 368                 if (o->flags & THEY_HAVE)
 369                         we_knew_they_have = 1;
 370                 else
 371                         o->flags |= THEY_HAVE;
 372                 if (!oldest_have || (commit->date < oldest_have))
 373                         oldest_have = commit->date;
 374                 for (parents = commit->parents;
 375                      parents;
 376                      parents = parents->next)
 377                         parents->item->object.flags |= THEY_HAVE;
 378         }
 379         if (!we_knew_they_have) {
 380                 add_object_array(o, NULL, &have_obj);
 381                 return 1;
 382         }
 383         return 0;
 384 }
 385
 386 static int reachable(struct commit *want)
 387 {
 388         struct commit_list *work = NULL;
 389
 390         insert_by_date(want, &work);
 391         while (work) {
 392                 struct commit_list *list = work->next;
 393                 struct commit *commit = work->item;
 394                 free(work);
 395                 work = list;
 396
 397                 if (commit->object.flags & THEY_HAVE) {
 398                         want->object.flags |= COMMON_KNOWN;
 399                         break;
 400                 }
 401                 if (!commit->object.parsed)
 402                         parse_object(commit->object.sha1);
 403                 if (commit->object.flags & REACHABLE)
 404                         continue;
 405                 commit->object.flags |= REACHABLE;
 406                 if (commit->date < oldest_have)
 407                         continue;
 408                 for (list = commit->parents; list; list = list->next) {
 409                         struct commit *parent = list->item;
 410                         if (!(parent->object.flags & REACHABLE))
 411                                 insert_by_date(parent, &work);
 412                 }
 413         }
 414         want->object.flags |= REACHABLE;
 415         clear_commit_marks(want, REACHABLE);
 416         free_commit_list(work);
 417         return (want->object.flags & COMMON_KNOWN);
 418 }
 419
 420 static int ok_to_give_up(void)
 421 {
 422         int i;
 423
 424         if (!have_obj.nr)
 425                 return 0;
 426
 427         for (i = 0; i < want_obj.nr; i++) {
 428                 struct object *want = want_obj.objects[i].item;
 429
 430                 if (want->flags & COMMON_KNOWN)
 431                         continue;
 432                 want = deref_tag(want, "a want line", 0);
 433                 if (!want || want->type != OBJ_COMMIT) {
 434                         /* no way to tell if this is reachable by
 435                          * looking at the ancestry chain alone, so
 436                          * leave a note to ourselves not to worry about
 437                          * this object anymore.
 438                          */
 439                         want_obj.objects[i].item->flags |= COMMON_KNOWN;
 440                         continue;
 441                 }
 442                 if (!reachable((struct commit *)want))
 443                         return 0;
 444         }
 445         return 1;
 446 }
 447
 448 static int get_common_commits(void)
 449 {
 450         static char line[1000];
 451         unsigned char sha1[20];
 452         char hex[41], last_hex[41];
 453         int len;
 454
 455         track_object_refs = 0;
 456         save_commit_buffer = 0;
 457
 458         for(;;) {
 459                 len = packet_read_line(0, line, sizeof(line));
 460                 reset_timeout();
 461
 462                 if (!len) {
 463                         if (have_obj.nr == 0 || multi_ack)
 464                                 packet_write(1, "NAK\n");
 465                         continue;
 466                 }
 467                 len = strip(line, len);
 468                 if (!prefixcmp(line, "have ")) {
 469                         switch (got_sha1(line+5, sha1)) {
 470                         case -1: /* they have what we do not */
 471                                 if (multi_ack && ok_to_give_up())
 472                                         packet_write(1, "ACK %s continue\n",
 473                                                      sha1_to_hex(sha1));
 474                                 break;
 475                         default:
 476                                 memcpy(hex, sha1_to_hex(sha1), 41);
 477                                 if (multi_ack) {
 478                                         const char *msg = "ACK %s continue\n";
 479                                         packet_write(1, msg, hex);
 480                                         memcpy(last_hex, hex, 41);
 481                                 }
 482                                 else if (have_obj.nr == 1)
 483                                         packet_write(1, "ACK %s\n", hex);
 484                                 break;
 485                         }
 486                         continue;
 487                 }
 488                 if (!strcmp(line, "done")) {
 489                         if (have_obj.nr > 0) {
 490                                 if (multi_ack)
 491                                         packet_write(1, "ACK %s\n", last_hex);
 492                                 return 0;
 493                         }
 494                         packet_write(1, "NAK\n");
 495                         return -1;
 496                 }
 497                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 498         }
 499 }
 500
 501 static void receive_needs(void)
 502 {
 503         struct object_array shallows = {0, 0, NULL};
 504         static char line[1000];
 505         int len, depth = 0;
 506
 507         for (;;) {
 508                 struct object *o;
 509                 unsigned char sha1_buf[20];
 510                 len = packet_read_line(0, line, sizeof(line));
 511                 reset_timeout();
 512                 if (!len)
 513                         break;
 514
 515                 if (!prefixcmp(line, "shallow ")) {
 516                         unsigned char sha1[20];
 517                         struct object *object;
 518                         use_thin_pack = 0;
 519                         if (get_sha1(line + 8, sha1))
 520                                 die("invalid shallow line: %s", line);
 521                         object = parse_object(sha1);
 522                         if (!object)
 523                                 die("did not find object for %s", line);
 524                         object->flags |= CLIENT_SHALLOW;
 525                         add_object_array(object, NULL, &shallows);
 526                         continue;
 527                 }
 528                 if (!prefixcmp(line, "deepen ")) {
 529                         char *end;
 530                         use_thin_pack = 0;
 531                         depth = strtol(line + 7, &end, 0);
 532                         if (end == line + 7 || depth <= 0)
 533                                 die("Invalid deepen: %s", line);
 534                         continue;
 535                 }
 536                 if (prefixcmp(line, "want ") ||
 537                     get_sha1_hex(line+5, sha1_buf))
 538                         die("git-upload-pack: protocol error, "
 539                             "expected to get sha, not '%s'", line);
 540                 if (strstr(line+45, "multi_ack"))
 541                         multi_ack = 1;
 542                 if (strstr(line+45, "thin-pack"))
 543                         use_thin_pack = 1;
 544                 if (strstr(line+45, "ofs-delta"))
 545                         use_ofs_delta = 1;
 546                 if (strstr(line+45, "side-band-64k"))
 547                         use_sideband = LARGE_PACKET_MAX;
 548                 else if (strstr(line+45, "side-band"))
 549                         use_sideband = DEFAULT_PACKET_MAX;
 550                 if (strstr(line+45, "no-progress"))
 551                         no_progress = 1;
 552
 553                 /* We have sent all our refs already, and the other end
 554                  * should have chosen out of them; otherwise they are
 555                  * asking for nonsense.
 556                  *
 557                  * Hmph.  We may later want to allow "want" line that
 558                  * asks for something like "master~10" (symbolic)...
 559                  * would it make sense?  I don't know.
 560                  */
 561                 o = lookup_object(sha1_buf);
 562                 if (!o || !(o->flags & OUR_REF))
 563                         die("git-upload-pack: not our ref %s", line+5);
 564                 if (!(o->flags & WANTED)) {
 565                         o->flags |= WANTED;
 566                         add_object_array(o, NULL, &want_obj);
 567                 }
 568         }
 569         if (depth == 0 && shallows.nr == 0)
 570                 return;
 571         if (depth > 0) {
 572                 struct commit_list *result, *backup;
 573                 int i;
 574                 backup = result = get_shallow_commits(&want_obj, depth,
 575                         SHALLOW, NOT_SHALLOW);
 576                 while (result) {
 577                         struct object *object = &result->item->object;
 578                         if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
 579                                 packet_write(1, "shallow %s",
 580                                                 sha1_to_hex(object->sha1));
 581                                 register_shallow(object->sha1);
 582                         }
 583                         result = result->next;
 584                 }
 585                 free_commit_list(backup);
 586                 for (i = 0; i < shallows.nr; i++) {
 587                         struct object *object = shallows.objects[i].item;
 588                         if (object->flags & NOT_SHALLOW) {
 589                                 struct commit_list *parents;
 590                                 packet_write(1, "unshallow %s",
 591                                         sha1_to_hex(object->sha1));
 592                                 object->flags &= ~CLIENT_SHALLOW;
 593                                 /* make sure the real parents are parsed */
 594                                 unregister_shallow(object->sha1);
 595                                 object->parsed = 0;
 596                                 parse_commit((struct commit *)object);
 597                                 parents = ((struct commit *)object)->parents;
 598                                 while (parents) {
 599                                         add_object_array(&parents->item->object,
 600                                                         NULL, &want_obj);
 601                                         parents = parents->next;
 602                                 }
 603                         }
 604                         /* make sure commit traversal conforms to client */
 605                         register_shallow(object->sha1);
 606                 }
 607                 packet_flush(1);
 608         } else
 609                 if (shallows.nr > 0) {
 610                         int i;
 611                         for (i = 0; i < shallows.nr; i++)
 612                                 register_shallow(shallows.objects[i].item->sha1);
 613                 }
 614         free(shallows.objects);
 615 }
 616
 617 static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 618 {
 619         static const char *capabilities = "multi_ack thin-pack side-band"
 620                 " side-band-64k ofs-delta shallow no-progress";
 621         struct object *o = parse_object(sha1);
 622
 623         if (!o)
 624                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 625
 626         if (capabilities)
 627                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 628                         0, capabilities);
 629         else
 630                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 631         capabilities = NULL;
 632         if (!(o->flags & OUR_REF)) {
 633                 o->flags |= OUR_REF;
 634                 nr_our_refs++;
 635         }
 636         if (o->type == OBJ_TAG) {
 637                 o = deref_tag(o, refname, 0);
 638                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 639         }
 640         return 0;
 641 }
 642
 643 static void upload_pack(void)
 644 {
 645         reset_timeout();
 646         head_ref(send_ref, NULL);
 647         for_each_ref(send_ref, NULL);
 648         packet_flush(1);
 649         receive_needs();
 650         if (want_obj.nr) {
 651                 get_common_commits();
 652                 create_pack_file();
 653         }
 654 }
 655
 656 int main(int argc, char **argv)
 657 {
 658         char *dir;
 659         int i;
 660         int strict = 0;
 661
 662         for (i = 1; i < argc; i++) {
 663                 char *arg = argv[i];
 664
 665                 if (arg[0] != '-')
 666                         break;
 667                 if (!strcmp(arg, "--strict")) {
 668                         strict = 1;
 669                         continue;
 670                 }
 671                 if (!prefixcmp(arg, "--timeout=")) {
 672                         timeout = atoi(arg+10);
 673                         continue;
 674                 }
 675                 if (!strcmp(arg, "--")) {
 676                         i++;
 677                         break;
 678                 }
 679         }
 680
 681         if (i != argc-1)
 682                 usage(upload_pack_usage);
 683         dir = argv[i];
 684
 685         if (!enter_repo(dir, strict))
 686                 die("'%s': unable to chdir or not a git archive", dir);
 687         if (is_repository_shallow())
 688                 die("attempt to fetch/clone from a shallow repository");
 689         upload_pack();
 690         return 0;
 691 }