git.oblomov.eu Git - git/blob - fetch-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6 #include "exec_cmd.h"
   7 #include "pack.h"
   8 #include "sideband.h"
   9 #include "fetch-pack.h"
  10 #include "remote.h"
  11 #include "run-command.h"
  12 #include "transport.h"
  13 #include "version.h"
  14
  15 static int transfer_unpack_limit = -1;
  16 static int fetch_unpack_limit = -1;
  17 static int unpack_limit = 100;
  18 static int prefer_ofs_delta = 1;
  19 static int no_done;
  20 static int fetch_fsck_objects = -1;
  21 static int transfer_fsck_objects = -1;
  22 static int agent_supported;
  23 static struct lock_file shallow_lock;
  24 static const char *alternate_shallow_file;
  25
  26 #define COMPLETE        (1U << 0)
  27 #define COMMON          (1U << 1)
  28 #define COMMON_REF      (1U << 2)
  29 #define SEEN            (1U << 3)
  30 #define POPPED          (1U << 4)
  31
  32 static int marked;
  33
  34 /*
  35  * After sending this many "have"s if we do not get any new ACK , we
  36  * give up traversing our history.
  37  */
  38 #define MAX_IN_VAIN 256
  39
  40 static struct commit_list *rev_list;
  41 static int non_common_revs, multi_ack, use_sideband, allow_tip_sha1_in_want;
  42
  43 static void rev_list_push(struct commit *commit, int mark)
  44 {
  45         if (!(commit->object.flags & mark)) {
  46                 commit->object.flags |= mark;
  47
  48                 if (!(commit->object.parsed))
  49                         if (parse_commit(commit))
  50                                 return;
  51
  52                 commit_list_insert_by_date(commit, &rev_list);
  53
  54                 if (!(commit->object.flags & COMMON))
  55                         non_common_revs++;
  56         }
  57 }
  58
  59 static int rev_list_insert_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  60 {
  61         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  62
  63         if (o && o->type == OBJ_COMMIT)
  64                 rev_list_push((struct commit *)o, SEEN);
  65
  66         return 0;
  67 }
  68
  69 static int clear_marks(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  70 {
  71         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  72
  73         if (o && o->type == OBJ_COMMIT)
  74                 clear_commit_marks((struct commit *)o,
  75                                    COMMON | COMMON_REF | SEEN | POPPED);
  76         return 0;
  77 }
  78
  79 /*
  80    This function marks a rev and its ancestors as common.
  81    In some cases, it is desirable to mark only the ancestors (for example
  82    when only the server does not yet know that they are common).
  83 */
  84
  85 static void mark_common(struct commit *commit,
  86                 int ancestors_only, int dont_parse)
  87 {
  88         if (commit != NULL && !(commit->object.flags & COMMON)) {
  89                 struct object *o = (struct object *)commit;
  90
  91                 if (!ancestors_only)
  92                         o->flags |= COMMON;
  93
  94                 if (!(o->flags & SEEN))
  95                         rev_list_push(commit, SEEN);
  96                 else {
  97                         struct commit_list *parents;
  98
  99                         if (!ancestors_only && !(o->flags & POPPED))
 100                                 non_common_revs--;
 101                         if (!o->parsed && !dont_parse)
 102                                 if (parse_commit(commit))
 103                                         return;
 104
 105                         for (parents = commit->parents;
 106                                         parents;
 107                                         parents = parents->next)
 108                                 mark_common(parents->item, 0, dont_parse);
 109                 }
 110         }
 111 }
 112
 113 /*
 114   Get the next rev to send, ignoring the common.
 115 */
 116
 117 static const unsigned char *get_rev(void)
 118 {
 119         struct commit *commit = NULL;
 120
 121         while (commit == NULL) {
 122                 unsigned int mark;
 123                 struct commit_list *parents;
 124
 125                 if (rev_list == NULL || non_common_revs == 0)
 126                         return NULL;
 127
 128                 commit = rev_list->item;
 129                 if (!commit->object.parsed)
 130                         parse_commit(commit);
 131                 parents = commit->parents;
 132
 133                 commit->object.flags |= POPPED;
 134                 if (!(commit->object.flags & COMMON))
 135                         non_common_revs--;
 136
 137                 if (commit->object.flags & COMMON) {
 138                         /* do not send "have", and ignore ancestors */
 139                         commit = NULL;
 140                         mark = COMMON | SEEN;
 141                 } else if (commit->object.flags & COMMON_REF)
 142                         /* send "have", and ignore ancestors */
 143                         mark = COMMON | SEEN;
 144                 else
 145                         /* send "have", also for its ancestors */
 146                         mark = SEEN;
 147
 148                 while (parents) {
 149                         if (!(parents->item->object.flags & SEEN))
 150                                 rev_list_push(parents->item, mark);
 151                         if (mark & COMMON)
 152                                 mark_common(parents->item, 1, 0);
 153                         parents = parents->next;
 154                 }
 155
 156                 rev_list = rev_list->next;
 157         }
 158
 159         return commit->object.sha1;
 160 }
 161
 162 enum ack_type {
 163         NAK = 0,
 164         ACK,
 165         ACK_continue,
 166         ACK_common,
 167         ACK_ready
 168 };
 169
 170 static void consume_shallow_list(struct fetch_pack_args *args, int fd)
 171 {
 172         if (args->stateless_rpc && args->depth > 0) {
 173                 /* If we sent a depth we will get back "duplicate"
 174                  * shallow and unshallow commands every time there
 175                  * is a block of have lines exchanged.
 176                  */
 177                 char *line;
 178                 while ((line = packet_read_line(fd, NULL))) {
 179                         if (!prefixcmp(line, "shallow "))
 180                                 continue;
 181                         if (!prefixcmp(line, "unshallow "))
 182                                 continue;
 183                         die("git fetch-pack: expected shallow list");
 184                 }
 185         }
 186 }
 187
 188 struct write_shallow_data {
 189         struct strbuf *out;
 190         int use_pack_protocol;
 191         int count;
 192 };
 193
 194 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 195 {
 196         struct write_shallow_data *data = cb_data;
 197         const char *hex = sha1_to_hex(graft->sha1);
 198         data->count++;
 199         if (data->use_pack_protocol)
 200                 packet_buf_write(data->out, "shallow %s", hex);
 201         else {
 202                 strbuf_addstr(data->out, hex);
 203                 strbuf_addch(data->out, '\n');
 204         }
 205         return 0;
 206 }
 207
 208 static int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
 209 {
 210         struct write_shallow_data data;
 211         data.out = out;
 212         data.use_pack_protocol = use_pack_protocol;
 213         data.count = 0;
 214         for_each_commit_graft(write_one_shallow, &data);
 215         return data.count;
 216 }
 217
 218 static enum ack_type get_ack(int fd, unsigned char *result_sha1)
 219 {
 220         int len;
 221         char *line = packet_read_line(fd, &len);
 222
 223         if (!len)
 224                 die("git fetch-pack: expected ACK/NAK, got EOF");
 225         if (!strcmp(line, "NAK"))
 226                 return NAK;
 227         if (!prefixcmp(line, "ACK ")) {
 228                 if (!get_sha1_hex(line+4, result_sha1)) {
 229                         if (len < 45)
 230                                 return ACK;
 231                         if (strstr(line+45, "continue"))
 232                                 return ACK_continue;
 233                         if (strstr(line+45, "common"))
 234                                 return ACK_common;
 235                         if (strstr(line+45, "ready"))
 236                                 return ACK_ready;
 237                         return ACK;
 238                 }
 239         }
 240         die("git fetch_pack: expected ACK/NAK, got '%s'", line);
 241 }
 242
 243 static void send_request(struct fetch_pack_args *args,
 244                          int fd, struct strbuf *buf)
 245 {
 246         if (args->stateless_rpc) {
 247                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 248                 packet_flush(fd);
 249         } else
 250                 write_or_die(fd, buf->buf, buf->len);
 251 }
 252
 253 static void insert_one_alternate_ref(const struct ref *ref, void *unused)
 254 {
 255         rev_list_insert_ref(NULL, ref->old_sha1, 0, NULL);
 256 }
 257
 258 #define INITIAL_FLUSH 16
 259 #define PIPESAFE_FLUSH 32
 260 #define LARGE_FLUSH 1024
 261
 262 static int next_flush(struct fetch_pack_args *args, int count)
 263 {
 264         int flush_limit = args->stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
 265
 266         if (count < flush_limit)
 267                 count <<= 1;
 268         else
 269                 count += flush_limit;
 270         return count;
 271 }
 272
 273 static int find_common(struct fetch_pack_args *args,
 274                        int fd[2], unsigned char *result_sha1,
 275                        struct ref *refs)
 276 {
 277         int fetching;
 278         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 279         const unsigned char *sha1;
 280         unsigned in_vain = 0;
 281         int got_continue = 0;
 282         int got_ready = 0;
 283         struct strbuf req_buf = STRBUF_INIT;
 284         size_t state_len = 0;
 285
 286         if (args->stateless_rpc && multi_ack == 1)
 287                 die("--stateless-rpc requires multi_ack_detailed");
 288         if (marked)
 289                 for_each_ref(clear_marks, NULL);
 290         marked = 1;
 291
 292         for_each_ref(rev_list_insert_ref, NULL);
 293         for_each_alternate_ref(insert_one_alternate_ref, NULL);
 294
 295         fetching = 0;
 296         for ( ; refs ; refs = refs->next) {
 297                 unsigned char *remote = refs->old_sha1;
 298                 const char *remote_hex;
 299                 struct object *o;
 300
 301                 /*
 302                  * If that object is complete (i.e. it is an ancestor of a
 303                  * local ref), we tell them we have it but do not have to
 304                  * tell them about its ancestors, which they already know
 305                  * about.
 306                  *
 307                  * We use lookup_object here because we are only
 308                  * interested in the case we *know* the object is
 309                  * reachable and we have already scanned it.
 310                  */
 311                 if (((o = lookup_object(remote)) != NULL) &&
 312                                 (o->flags & COMPLETE)) {
 313                         continue;
 314                 }
 315
 316                 remote_hex = sha1_to_hex(remote);
 317                 if (!fetching) {
 318                         struct strbuf c = STRBUF_INIT;
 319                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 320                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 321                         if (no_done)            strbuf_addstr(&c, " no-done");
 322                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 323                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 324                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 325                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 326                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 327                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 328                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 329                                                             git_user_agent_sanitized());
 330                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 331                         strbuf_release(&c);
 332                 } else
 333                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 334                 fetching++;
 335         }
 336
 337         if (!fetching) {
 338                 strbuf_release(&req_buf);
 339                 packet_flush(fd[1]);
 340                 return 1;
 341         }
 342
 343         if (is_repository_shallow())
 344                 write_shallow_commits(&req_buf, 1);
 345         if (args->depth > 0)
 346                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 347         packet_buf_flush(&req_buf);
 348         state_len = req_buf.len;
 349
 350         if (args->depth > 0) {
 351                 char *line;
 352                 unsigned char sha1[20];
 353
 354                 send_request(args, fd[1], &req_buf);
 355                 while ((line = packet_read_line(fd[0], NULL))) {
 356                         if (!prefixcmp(line, "shallow ")) {
 357                                 if (get_sha1_hex(line + 8, sha1))
 358                                         die("invalid shallow line: %s", line);
 359                                 register_shallow(sha1);
 360                                 continue;
 361                         }
 362                         if (!prefixcmp(line, "unshallow ")) {
 363                                 if (get_sha1_hex(line + 10, sha1))
 364                                         die("invalid unshallow line: %s", line);
 365                                 if (!lookup_object(sha1))
 366                                         die("object not found: %s", line);
 367                                 /* make sure that it is parsed as shallow */
 368                                 if (!parse_object(sha1))
 369                                         die("error in object: %s", line);
 370                                 if (unregister_shallow(sha1))
 371                                         die("no shallow found: %s", line);
 372                                 continue;
 373                         }
 374                         die("expected shallow/unshallow, got %s", line);
 375                 }
 376         } else if (!args->stateless_rpc)
 377                 send_request(args, fd[1], &req_buf);
 378
 379         if (!args->stateless_rpc) {
 380                 /* If we aren't using the stateless-rpc interface
 381                  * we don't need to retain the headers.
 382                  */
 383                 strbuf_setlen(&req_buf, 0);
 384                 state_len = 0;
 385         }
 386
 387         flushes = 0;
 388         retval = -1;
 389         while ((sha1 = get_rev())) {
 390                 packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
 391                 if (args->verbose)
 392                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 393                 in_vain++;
 394                 if (flush_at <= ++count) {
 395                         int ack;
 396
 397                         packet_buf_flush(&req_buf);
 398                         send_request(args, fd[1], &req_buf);
 399                         strbuf_setlen(&req_buf, state_len);
 400                         flushes++;
 401                         flush_at = next_flush(args, count);
 402
 403                         /*
 404                          * We keep one window "ahead" of the other side, and
 405                          * will wait for an ACK only on the next one
 406                          */
 407                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 408                                 continue;
 409
 410                         consume_shallow_list(args, fd[0]);
 411                         do {
 412                                 ack = get_ack(fd[0], result_sha1);
 413                                 if (args->verbose && ack)
 414                                         fprintf(stderr, "got ack %d %s\n", ack,
 415                                                         sha1_to_hex(result_sha1));
 416                                 switch (ack) {
 417                                 case ACK:
 418                                         flushes = 0;
 419                                         multi_ack = 0;
 420                                         retval = 0;
 421                                         goto done;
 422                                 case ACK_common:
 423                                 case ACK_ready:
 424                                 case ACK_continue: {
 425                                         struct commit *commit =
 426                                                 lookup_commit(result_sha1);
 427                                         if (!commit)
 428                                                 die("invalid commit %s", sha1_to_hex(result_sha1));
 429                                         if (args->stateless_rpc
 430                                          && ack == ACK_common
 431                                          && !(commit->object.flags & COMMON)) {
 432                                                 /* We need to replay the have for this object
 433                                                  * on the next RPC request so the peer knows
 434                                                  * it is in common with us.
 435                                                  */
 436                                                 const char *hex = sha1_to_hex(result_sha1);
 437                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 438                                                 state_len = req_buf.len;
 439                                         }
 440                                         mark_common(commit, 0, 1);
 441                                         retval = 0;
 442                                         in_vain = 0;
 443                                         got_continue = 1;
 444                                         if (ack == ACK_ready) {
 445                                                 rev_list = NULL;
 446                                                 got_ready = 1;
 447                                         }
 448                                         break;
 449                                         }
 450                                 }
 451                         } while (ack);
 452                         flushes--;
 453                         if (got_continue && MAX_IN_VAIN < in_vain) {
 454                                 if (args->verbose)
 455                                         fprintf(stderr, "giving up\n");
 456                                 break; /* give up */
 457                         }
 458                 }
 459         }
 460 done:
 461         if (!got_ready || !no_done) {
 462                 packet_buf_write(&req_buf, "done\n");
 463                 send_request(args, fd[1], &req_buf);
 464         }
 465         if (args->verbose)
 466                 fprintf(stderr, "done\n");
 467         if (retval != 0) {
 468                 multi_ack = 0;
 469                 flushes++;
 470         }
 471         strbuf_release(&req_buf);
 472
 473         consume_shallow_list(args, fd[0]);
 474         while (flushes || multi_ack) {
 475                 int ack = get_ack(fd[0], result_sha1);
 476                 if (ack) {
 477                         if (args->verbose)
 478                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 479                                         sha1_to_hex(result_sha1));
 480                         if (ack == ACK)
 481                                 return 0;
 482                         multi_ack = 1;
 483                         continue;
 484                 }
 485                 flushes--;
 486         }
 487         /* it is no error to fetch into a completely empty repo */
 488         return count ? retval : 0;
 489 }
 490
 491 static struct commit_list *complete;
 492
 493 static int mark_complete(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 494 {
 495         struct object *o = parse_object(sha1);
 496
 497         while (o && o->type == OBJ_TAG) {
 498                 struct tag *t = (struct tag *) o;
 499                 if (!t->tagged)
 500                         break; /* broken repository */
 501                 o->flags |= COMPLETE;
 502                 o = parse_object(t->tagged->sha1);
 503         }
 504         if (o && o->type == OBJ_COMMIT) {
 505                 struct commit *commit = (struct commit *)o;
 506                 if (!(commit->object.flags & COMPLETE)) {
 507                         commit->object.flags |= COMPLETE;
 508                         commit_list_insert_by_date(commit, &complete);
 509                 }
 510         }
 511         return 0;
 512 }
 513
 514 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 515                                          unsigned long cutoff)
 516 {
 517         while (complete && cutoff <= complete->item->date) {
 518                 if (args->verbose)
 519                         fprintf(stderr, "Marking %s as complete\n",
 520                                 sha1_to_hex(complete->item->object.sha1));
 521                 pop_most_recent_commit(&complete, COMPLETE);
 522         }
 523 }
 524
 525 static void filter_refs(struct fetch_pack_args *args,
 526                         struct ref **refs,
 527                         struct ref **sought, int nr_sought)
 528 {
 529         struct ref *newlist = NULL;
 530         struct ref **newtail = &newlist;
 531         struct ref *ref, *next;
 532         int i;
 533
 534         i = 0;
 535         for (ref = *refs; ref; ref = next) {
 536                 int keep = 0;
 537                 next = ref->next;
 538
 539                 if (!memcmp(ref->name, "refs/", 5) &&
 540                     check_refname_format(ref->name + 5, 0))
 541                         ; /* trash */
 542                 else {
 543                         while (i < nr_sought) {
 544                                 int cmp = strcmp(ref->name, sought[i]->name);
 545                                 if (cmp < 0)
 546                                         break; /* definitely do not have it */
 547                                 else if (cmp == 0) {
 548                                         keep = 1; /* definitely have it */
 549                                         sought[i]->matched = 1;
 550                                 }
 551                                 i++;
 552                         }
 553                 }
 554
 555                 if (!keep && args->fetch_all &&
 556                     (!args->depth || prefixcmp(ref->name, "refs/tags/")))
 557                         keep = 1;
 558
 559                 if (keep) {
 560                         *newtail = ref;
 561                         ref->next = NULL;
 562                         newtail = &ref->next;
 563                 } else {
 564                         free(ref);
 565                 }
 566         }
 567
 568         /* Append unmatched requests to the list */
 569         if (allow_tip_sha1_in_want) {
 570                 for (i = 0; i < nr_sought; i++) {
 571                         ref = sought[i];
 572                         if (ref->matched)
 573                                 continue;
 574                         if (get_sha1_hex(ref->name, ref->old_sha1))
 575                                 continue;
 576
 577                         ref->matched = 1;
 578                         *newtail = ref;
 579                         ref->next = NULL;
 580                         newtail = &ref->next;
 581                 }
 582         }
 583         *refs = newlist;
 584 }
 585
 586 static void mark_alternate_complete(const struct ref *ref, void *unused)
 587 {
 588         mark_complete(NULL, ref->old_sha1, 0, NULL);
 589 }
 590
 591 static int everything_local(struct fetch_pack_args *args,
 592                             struct ref **refs,
 593                             struct ref **sought, int nr_sought)
 594 {
 595         struct ref *ref;
 596         int retval;
 597         unsigned long cutoff = 0;
 598
 599         save_commit_buffer = 0;
 600
 601         for (ref = *refs; ref; ref = ref->next) {
 602                 struct object *o;
 603
 604                 if (!has_sha1_file(ref->old_sha1))
 605                         continue;
 606
 607                 o = parse_object(ref->old_sha1);
 608                 if (!o)
 609                         continue;
 610
 611                 /* We already have it -- which may mean that we were
 612                  * in sync with the other side at some time after
 613                  * that (it is OK if we guess wrong here).
 614                  */
 615                 if (o->type == OBJ_COMMIT) {
 616                         struct commit *commit = (struct commit *)o;
 617                         if (!cutoff || cutoff < commit->date)
 618                                 cutoff = commit->date;
 619                 }
 620         }
 621
 622         if (!args->depth) {
 623                 for_each_ref(mark_complete, NULL);
 624                 for_each_alternate_ref(mark_alternate_complete, NULL);
 625                 if (cutoff)
 626                         mark_recent_complete_commits(args, cutoff);
 627         }
 628
 629         /*
 630          * Mark all complete remote refs as common refs.
 631          * Don't mark them common yet; the server has to be told so first.
 632          */
 633         for (ref = *refs; ref; ref = ref->next) {
 634                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 635                                              NULL, 0);
 636
 637                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 638                         continue;
 639
 640                 if (!(o->flags & SEEN)) {
 641                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 642
 643                         mark_common((struct commit *)o, 1, 1);
 644                 }
 645         }
 646
 647         filter_refs(args, refs, sought, nr_sought);
 648
 649         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 650                 const unsigned char *remote = ref->old_sha1;
 651                 unsigned char local[20];
 652                 struct object *o;
 653
 654                 o = lookup_object(remote);
 655                 if (!o || !(o->flags & COMPLETE)) {
 656                         retval = 0;
 657                         if (!args->verbose)
 658                                 continue;
 659                         fprintf(stderr,
 660                                 "want %s (%s)\n", sha1_to_hex(remote),
 661                                 ref->name);
 662                         continue;
 663                 }
 664
 665                 hashcpy(ref->new_sha1, local);
 666                 if (!args->verbose)
 667                         continue;
 668                 fprintf(stderr,
 669                         "already have %s (%s)\n", sha1_to_hex(remote),
 670                         ref->name);
 671         }
 672         return retval;
 673 }
 674
 675 static int sideband_demux(int in, int out, void *data)
 676 {
 677         int *xd = data;
 678
 679         int ret = recv_sideband("fetch-pack", xd[0], out);
 680         close(out);
 681         return ret;
 682 }
 683
 684 static int get_pack(struct fetch_pack_args *args,
 685                     int xd[2], char **pack_lockfile)
 686 {
 687         struct async demux;
 688         const char *argv[22];
 689         char keep_arg[256];
 690         char hdr_arg[256];
 691         const char **av;
 692         int do_keep = args->keep_pack;
 693         struct child_process cmd;
 694
 695         memset(&demux, 0, sizeof(demux));
 696         if (use_sideband) {
 697                 /* xd[] is talking with upload-pack; subprocess reads from
 698                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 699                  * through demux->out.
 700                  */
 701                 demux.proc = sideband_demux;
 702                 demux.data = xd;
 703                 demux.out = -1;
 704                 if (start_async(&demux))
 705                         die("fetch-pack: unable to fork off sideband"
 706                             " demultiplexer");
 707         }
 708         else
 709                 demux.out = xd[0];
 710
 711         memset(&cmd, 0, sizeof(cmd));
 712         cmd.argv = argv;
 713         av = argv;
 714         *hdr_arg = 0;
 715         if (!args->keep_pack && unpack_limit) {
 716                 struct pack_header header;
 717
 718                 if (read_pack_header(demux.out, &header))
 719                         die("protocol error: bad pack header");
 720                 snprintf(hdr_arg, sizeof(hdr_arg),
 721                          "--pack_header=%"PRIu32",%"PRIu32,
 722                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 723                 if (ntohl(header.hdr_entries) < unpack_limit)
 724                         do_keep = 0;
 725                 else
 726                         do_keep = 1;
 727         }
 728
 729         if (alternate_shallow_file) {
 730                 *av++ = "--shallow-file";
 731                 *av++ = alternate_shallow_file;
 732         }
 733
 734         if (do_keep) {
 735                 if (pack_lockfile)
 736                         cmd.out = -1;
 737                 *av++ = "index-pack";
 738                 *av++ = "--stdin";
 739                 if (!args->quiet && !args->no_progress)
 740                         *av++ = "-v";
 741                 if (args->use_thin_pack)
 742                         *av++ = "--fix-thin";
 743                 if (args->lock_pack || unpack_limit) {
 744                         int s = sprintf(keep_arg,
 745                                         "--keep=fetch-pack %"PRIuMAX " on ", (uintmax_t) getpid());
 746                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 747                                 strcpy(keep_arg + s, "localhost");
 748                         *av++ = keep_arg;
 749                 }
 750         }
 751         else {
 752                 *av++ = "unpack-objects";
 753                 if (args->quiet || args->no_progress)
 754                         *av++ = "-q";
 755         }
 756         if (*hdr_arg)
 757                 *av++ = hdr_arg;
 758         if (fetch_fsck_objects >= 0
 759             ? fetch_fsck_objects
 760             : transfer_fsck_objects >= 0
 761             ? transfer_fsck_objects
 762             : 0)
 763                 *av++ = "--strict";
 764         *av++ = NULL;
 765
 766         cmd.in = demux.out;
 767         cmd.git_cmd = 1;
 768         if (start_command(&cmd))
 769                 die("fetch-pack: unable to fork off %s", argv[0]);
 770         if (do_keep && pack_lockfile) {
 771                 *pack_lockfile = index_pack_lockfile(cmd.out);
 772                 close(cmd.out);
 773         }
 774
 775         if (finish_command(&cmd))
 776                 die("%s failed", argv[0]);
 777         if (use_sideband && finish_async(&demux))
 778                 die("error in sideband demultiplexer");
 779         return 0;
 780 }
 781
 782 static int cmp_ref_by_name(const void *a_, const void *b_)
 783 {
 784         const struct ref *a = *((const struct ref **)a_);
 785         const struct ref *b = *((const struct ref **)b_);
 786         return strcmp(a->name, b->name);
 787 }
 788
 789 static void setup_alternate_shallow(void)
 790 {
 791         struct strbuf sb = STRBUF_INIT;
 792         int fd;
 793
 794         check_shallow_file_for_update();
 795         fd = hold_lock_file_for_update(&shallow_lock, git_path("shallow"),
 796                                        LOCK_DIE_ON_ERROR);
 797         if (write_shallow_commits(&sb, 0)) {
 798                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 799                         die_errno("failed to write to %s", shallow_lock.filename);
 800                 alternate_shallow_file = shallow_lock.filename;
 801         } else
 802                 /*
 803                  * is_repository_shallow() sees empty string as "no
 804                  * shallow file".
 805                  */
 806                 alternate_shallow_file = "";
 807         strbuf_release(&sb);
 808 }
 809
 810 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 811                                  int fd[2],
 812                                  const struct ref *orig_ref,
 813                                  struct ref **sought, int nr_sought,
 814                                  char **pack_lockfile)
 815 {
 816         struct ref *ref = copy_ref_list(orig_ref);
 817         unsigned char sha1[20];
 818         const char *agent_feature;
 819         int agent_len;
 820
 821         sort_ref_list(&ref, ref_compare_name);
 822         qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
 823
 824         if (is_repository_shallow() && !server_supports("shallow"))
 825                 die("Server does not support shallow clients");
 826         if (server_supports("multi_ack_detailed")) {
 827                 if (args->verbose)
 828                         fprintf(stderr, "Server supports multi_ack_detailed\n");
 829                 multi_ack = 2;
 830                 if (server_supports("no-done")) {
 831                         if (args->verbose)
 832                                 fprintf(stderr, "Server supports no-done\n");
 833                         if (args->stateless_rpc)
 834                                 no_done = 1;
 835                 }
 836         }
 837         else if (server_supports("multi_ack")) {
 838                 if (args->verbose)
 839                         fprintf(stderr, "Server supports multi_ack\n");
 840                 multi_ack = 1;
 841         }
 842         if (server_supports("side-band-64k")) {
 843                 if (args->verbose)
 844                         fprintf(stderr, "Server supports side-band-64k\n");
 845                 use_sideband = 2;
 846         }
 847         else if (server_supports("side-band")) {
 848                 if (args->verbose)
 849                         fprintf(stderr, "Server supports side-band\n");
 850                 use_sideband = 1;
 851         }
 852         if (server_supports("allow-tip-sha1-in-want")) {
 853                 if (args->verbose)
 854                         fprintf(stderr, "Server supports allow-tip-sha1-in-want\n");
 855                 allow_tip_sha1_in_want = 1;
 856         }
 857         if (!server_supports("thin-pack"))
 858                 args->use_thin_pack = 0;
 859         if (!server_supports("no-progress"))
 860                 args->no_progress = 0;
 861         if (!server_supports("include-tag"))
 862                 args->include_tag = 0;
 863         if (server_supports("ofs-delta")) {
 864                 if (args->verbose)
 865                         fprintf(stderr, "Server supports ofs-delta\n");
 866         } else
 867                 prefer_ofs_delta = 0;
 868
 869         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 870                 agent_supported = 1;
 871                 if (args->verbose && agent_len)
 872                         fprintf(stderr, "Server version is %.*s\n",
 873                                 agent_len, agent_feature);
 874         }
 875
 876         if (everything_local(args, &ref, sought, nr_sought)) {
 877                 packet_flush(fd[1]);
 878                 goto all_done;
 879         }
 880         if (find_common(args, fd, sha1, ref) < 0)
 881                 if (!args->keep_pack)
 882                         /* When cloning, it is not unusual to have
 883                          * no common commit.
 884                          */
 885                         warning("no common commits");
 886
 887         if (args->stateless_rpc)
 888                 packet_flush(fd[1]);
 889         if (args->depth > 0)
 890                 setup_alternate_shallow();
 891         if (get_pack(args, fd, pack_lockfile))
 892                 die("git fetch-pack: fetch failed.");
 893
 894  all_done:
 895         return ref;
 896 }
 897
 898 static int fetch_pack_config(const char *var, const char *value, void *cb)
 899 {
 900         if (strcmp(var, "fetch.unpacklimit") == 0) {
 901                 fetch_unpack_limit = git_config_int(var, value);
 902                 return 0;
 903         }
 904
 905         if (strcmp(var, "transfer.unpacklimit") == 0) {
 906                 transfer_unpack_limit = git_config_int(var, value);
 907                 return 0;
 908         }
 909
 910         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 911                 prefer_ofs_delta = git_config_bool(var, value);
 912                 return 0;
 913         }
 914
 915         if (!strcmp(var, "fetch.fsckobjects")) {
 916                 fetch_fsck_objects = git_config_bool(var, value);
 917                 return 0;
 918         }
 919
 920         if (!strcmp(var, "transfer.fsckobjects")) {
 921                 transfer_fsck_objects = git_config_bool(var, value);
 922                 return 0;
 923         }
 924
 925         return git_default_config(var, value, cb);
 926 }
 927
 928 static void fetch_pack_setup(void)
 929 {
 930         static int did_setup;
 931         if (did_setup)
 932                 return;
 933         git_config(fetch_pack_config, NULL);
 934         if (0 <= transfer_unpack_limit)
 935                 unpack_limit = transfer_unpack_limit;
 936         else if (0 <= fetch_unpack_limit)
 937                 unpack_limit = fetch_unpack_limit;
 938         did_setup = 1;
 939 }
 940
 941 static int remove_duplicates_in_refs(struct ref **ref, int nr)
 942 {
 943         struct string_list names = STRING_LIST_INIT_NODUP;
 944         int src, dst;
 945
 946         for (src = dst = 0; src < nr; src++) {
 947                 struct string_list_item *item;
 948                 item = string_list_insert(&names, ref[src]->name);
 949                 if (item->util)
 950                         continue; /* already have it */
 951                 item->util = ref[src];
 952                 if (src != dst)
 953                         ref[dst] = ref[src];
 954                 dst++;
 955         }
 956         for (src = dst; src < nr; src++)
 957                 ref[src] = NULL;
 958         string_list_clear(&names, 0);
 959         return dst;
 960 }
 961
 962 struct ref *fetch_pack(struct fetch_pack_args *args,
 963                        int fd[], struct child_process *conn,
 964                        const struct ref *ref,
 965                        const char *dest,
 966                        struct ref **sought, int nr_sought,
 967                        char **pack_lockfile)
 968 {
 969         struct ref *ref_cpy;
 970
 971         fetch_pack_setup();
 972         if (nr_sought)
 973                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
 974
 975         if (!ref) {
 976                 packet_flush(fd[1]);
 977                 die("no matching remote head");
 978         }
 979         ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought, pack_lockfile);
 980
 981         if (alternate_shallow_file) {
 982                 if (*alternate_shallow_file == '\0') { /* --unshallow */
 983                         unlink_or_warn(git_path("shallow"));
 984                         rollback_lock_file(&shallow_lock);
 985                 } else
 986                         commit_lock_file(&shallow_lock);
 987         }
 988
 989         reprepare_packed_git();
 990         return ref_cpy;
 991 }