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
  24 #define COMPLETE        (1U << 0)
  25 #define COMMON          (1U << 1)
  26 #define COMMON_REF      (1U << 2)
  27 #define SEEN            (1U << 3)
  28 #define POPPED          (1U << 4)
  29
  30 static int marked;
  31
  32 /*
  33  * After sending this many "have"s if we do not get any new ACK , we
  34  * give up traversing our history.
  35  */
  36 #define MAX_IN_VAIN 256
  37
  38 static struct commit_list *rev_list;
  39 static int non_common_revs, multi_ack, use_sideband, allow_tip_sha1_in_want;
  40
  41 static void rev_list_push(struct commit *commit, int mark)
  42 {
  43         if (!(commit->object.flags & mark)) {
  44                 commit->object.flags |= mark;
  45
  46                 if (!(commit->object.parsed))
  47                         if (parse_commit(commit))
  48                                 return;
  49
  50                 commit_list_insert_by_date(commit, &rev_list);
  51
  52                 if (!(commit->object.flags & COMMON))
  53                         non_common_revs++;
  54         }
  55 }
  56
  57 static int rev_list_insert_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  58 {
  59         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  60
  61         if (o && o->type == OBJ_COMMIT)
  62                 rev_list_push((struct commit *)o, SEEN);
  63
  64         return 0;
  65 }
  66
  67 static int clear_marks(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  68 {
  69         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  70
  71         if (o && o->type == OBJ_COMMIT)
  72                 clear_commit_marks((struct commit *)o,
  73                                    COMMON | COMMON_REF | SEEN | POPPED);
  74         return 0;
  75 }
  76
  77 /*
  78    This function marks a rev and its ancestors as common.
  79    In some cases, it is desirable to mark only the ancestors (for example
  80    when only the server does not yet know that they are common).
  81 */
  82
  83 static void mark_common(struct commit *commit,
  84                 int ancestors_only, int dont_parse)
  85 {
  86         if (commit != NULL && !(commit->object.flags & COMMON)) {
  87                 struct object *o = (struct object *)commit;
  88
  89                 if (!ancestors_only)
  90                         o->flags |= COMMON;
  91
  92                 if (!(o->flags & SEEN))
  93                         rev_list_push(commit, SEEN);
  94                 else {
  95                         struct commit_list *parents;
  96
  97                         if (!ancestors_only && !(o->flags & POPPED))
  98                                 non_common_revs--;
  99                         if (!o->parsed && !dont_parse)
 100                                 if (parse_commit(commit))
 101                                         return;
 102
 103                         for (parents = commit->parents;
 104                                         parents;
 105                                         parents = parents->next)
 106                                 mark_common(parents->item, 0, dont_parse);
 107                 }
 108         }
 109 }
 110
 111 /*
 112   Get the next rev to send, ignoring the common.
 113 */
 114
 115 static const unsigned char *get_rev(void)
 116 {
 117         struct commit *commit = NULL;
 118
 119         while (commit == NULL) {
 120                 unsigned int mark;
 121                 struct commit_list *parents;
 122
 123                 if (rev_list == NULL || non_common_revs == 0)
 124                         return NULL;
 125
 126                 commit = rev_list->item;
 127                 if (!commit->object.parsed)
 128                         parse_commit(commit);
 129                 parents = commit->parents;
 130
 131                 commit->object.flags |= POPPED;
 132                 if (!(commit->object.flags & COMMON))
 133                         non_common_revs--;
 134
 135                 if (commit->object.flags & COMMON) {
 136                         /* do not send "have", and ignore ancestors */
 137                         commit = NULL;
 138                         mark = COMMON | SEEN;
 139                 } else if (commit->object.flags & COMMON_REF)
 140                         /* send "have", and ignore ancestors */
 141                         mark = COMMON | SEEN;
 142                 else
 143                         /* send "have", also for its ancestors */
 144                         mark = SEEN;
 145
 146                 while (parents) {
 147                         if (!(parents->item->object.flags & SEEN))
 148                                 rev_list_push(parents->item, mark);
 149                         if (mark & COMMON)
 150                                 mark_common(parents->item, 1, 0);
 151                         parents = parents->next;
 152                 }
 153
 154                 rev_list = rev_list->next;
 155         }
 156
 157         return commit->object.sha1;
 158 }
 159
 160 enum ack_type {
 161         NAK = 0,
 162         ACK,
 163         ACK_continue,
 164         ACK_common,
 165         ACK_ready
 166 };
 167
 168 static void consume_shallow_list(struct fetch_pack_args *args, int fd)
 169 {
 170         if (args->stateless_rpc && args->depth > 0) {
 171                 /* If we sent a depth we will get back "duplicate"
 172                  * shallow and unshallow commands every time there
 173                  * is a block of have lines exchanged.
 174                  */
 175                 char line[1000];
 176                 while (packet_read_line(fd, line, sizeof(line))) {
 177                         if (!prefixcmp(line, "shallow "))
 178                                 continue;
 179                         if (!prefixcmp(line, "unshallow "))
 180                                 continue;
 181                         die("git fetch-pack: expected shallow list");
 182                 }
 183         }
 184 }
 185
 186 struct write_shallow_data {
 187         struct strbuf *out;
 188         int use_pack_protocol;
 189         int count;
 190 };
 191
 192 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 193 {
 194         struct write_shallow_data *data = cb_data;
 195         const char *hex = sha1_to_hex(graft->sha1);
 196         data->count++;
 197         if (data->use_pack_protocol)
 198                 packet_buf_write(data->out, "shallow %s", hex);
 199         else {
 200                 strbuf_addstr(data->out, hex);
 201                 strbuf_addch(data->out, '\n');
 202         }
 203         return 0;
 204 }
 205
 206 static int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
 207 {
 208         struct write_shallow_data data;
 209         data.out = out;
 210         data.use_pack_protocol = use_pack_protocol;
 211         data.count = 0;
 212         for_each_commit_graft(write_one_shallow, &data);
 213         return data.count;
 214 }
 215
 216 static enum ack_type get_ack(int fd, unsigned char *result_sha1)
 217 {
 218         static char line[1000];
 219         int len = packet_read_line(fd, line, sizeof(line));
 220
 221         if (!len)
 222                 die("git fetch-pack: expected ACK/NAK, got EOF");
 223         if (line[len-1] == '\n')
 224                 line[--len] = 0;
 225         if (!strcmp(line, "NAK"))
 226                 return NAK;
 227         if (!prefixcmp(line, "ACK ")) {
 228                 if (!get_sha1_hex(line+4, result_sha1)) {
 229                         if (strstr(line+45, "continue"))
 230                                 return ACK_continue;
 231                         if (strstr(line+45, "common"))
 232                                 return ACK_common;
 233                         if (strstr(line+45, "ready"))
 234                                 return ACK_ready;
 235                         return ACK;
 236                 }
 237         }
 238         die("git fetch_pack: expected ACK/NAK, got '%s'", line);
 239 }
 240
 241 static void send_request(struct fetch_pack_args *args,
 242                          int fd, struct strbuf *buf)
 243 {
 244         if (args->stateless_rpc) {
 245                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 246                 packet_flush(fd);
 247         } else
 248                 safe_write(fd, buf->buf, buf->len);
 249 }
 250
 251 static void insert_one_alternate_ref(const struct ref *ref, void *unused)
 252 {
 253         rev_list_insert_ref(NULL, ref->old_sha1, 0, NULL);
 254 }
 255
 256 #define INITIAL_FLUSH 16
 257 #define PIPESAFE_FLUSH 32
 258 #define LARGE_FLUSH 1024
 259
 260 static int next_flush(struct fetch_pack_args *args, int count)
 261 {
 262         int flush_limit = args->stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
 263
 264         if (count < flush_limit)
 265                 count <<= 1;
 266         else
 267                 count += flush_limit;
 268         return count;
 269 }
 270
 271 static int find_common(struct fetch_pack_args *args,
 272                        int fd[2], unsigned char *result_sha1,
 273                        struct ref *refs)
 274 {
 275         int fetching;
 276         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 277         const unsigned char *sha1;
 278         unsigned in_vain = 0;
 279         int got_continue = 0;
 280         int got_ready = 0;
 281         struct strbuf req_buf = STRBUF_INIT;
 282         size_t state_len = 0;
 283
 284         if (args->stateless_rpc && multi_ack == 1)
 285                 die("--stateless-rpc requires multi_ack_detailed");
 286         if (marked)
 287                 for_each_ref(clear_marks, NULL);
 288         marked = 1;
 289
 290         for_each_ref(rev_list_insert_ref, NULL);
 291         for_each_alternate_ref(insert_one_alternate_ref, NULL);
 292
 293         fetching = 0;
 294         for ( ; refs ; refs = refs->next) {
 295                 unsigned char *remote = refs->old_sha1;
 296                 const char *remote_hex;
 297                 struct object *o;
 298
 299                 /*
 300                  * If that object is complete (i.e. it is an ancestor of a
 301                  * local ref), we tell them we have it but do not have to
 302                  * tell them about its ancestors, which they already know
 303                  * about.
 304                  *
 305                  * We use lookup_object here because we are only
 306                  * interested in the case we *know* the object is
 307                  * reachable and we have already scanned it.
 308                  */
 309                 if (((o = lookup_object(remote)) != NULL) &&
 310                                 (o->flags & COMPLETE)) {
 311                         continue;
 312                 }
 313
 314                 remote_hex = sha1_to_hex(remote);
 315                 if (!fetching) {
 316                         struct strbuf c = STRBUF_INIT;
 317                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 318                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 319                         if (no_done)            strbuf_addstr(&c, " no-done");
 320                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 321                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 322                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 323                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 324                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 325                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 326                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 327                                                             git_user_agent_sanitized());
 328                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 329                         strbuf_release(&c);
 330                 } else
 331                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 332                 fetching++;
 333         }
 334
 335         if (!fetching) {
 336                 strbuf_release(&req_buf);
 337                 packet_flush(fd[1]);
 338                 return 1;
 339         }
 340
 341         if (is_repository_shallow())
 342                 write_shallow_commits(&req_buf, 1);
 343         if (args->depth > 0)
 344                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 345         packet_buf_flush(&req_buf);
 346         state_len = req_buf.len;
 347
 348         if (args->depth > 0) {
 349                 char line[1024];
 350                 unsigned char sha1[20];
 351
 352                 send_request(args, fd[1], &req_buf);
 353                 while (packet_read_line(fd[0], line, sizeof(line))) {
 354                         if (!prefixcmp(line, "shallow ")) {
 355                                 if (get_sha1_hex(line + 8, sha1))
 356                                         die("invalid shallow line: %s", line);
 357                                 register_shallow(sha1);
 358                                 continue;
 359                         }
 360                         if (!prefixcmp(line, "unshallow ")) {
 361                                 if (get_sha1_hex(line + 10, sha1))
 362                                         die("invalid unshallow line: %s", line);
 363                                 if (!lookup_object(sha1))
 364                                         die("object not found: %s", line);
 365                                 /* make sure that it is parsed as shallow */
 366                                 if (!parse_object(sha1))
 367                                         die("error in object: %s", line);
 368                                 if (unregister_shallow(sha1))
 369                                         die("no shallow found: %s", line);
 370                                 continue;
 371                         }
 372                         die("expected shallow/unshallow, got %s", line);
 373                 }
 374         } else if (!args->stateless_rpc)
 375                 send_request(args, fd[1], &req_buf);
 376
 377         if (!args->stateless_rpc) {
 378                 /* If we aren't using the stateless-rpc interface
 379                  * we don't need to retain the headers.
 380                  */
 381                 strbuf_setlen(&req_buf, 0);
 382                 state_len = 0;
 383         }
 384
 385         flushes = 0;
 386         retval = -1;
 387         while ((sha1 = get_rev())) {
 388                 packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
 389                 if (args->verbose)
 390                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 391                 in_vain++;
 392                 if (flush_at <= ++count) {
 393                         int ack;
 394
 395                         packet_buf_flush(&req_buf);
 396                         send_request(args, fd[1], &req_buf);
 397                         strbuf_setlen(&req_buf, state_len);
 398                         flushes++;
 399                         flush_at = next_flush(args, count);
 400
 401                         /*
 402                          * We keep one window "ahead" of the other side, and
 403                          * will wait for an ACK only on the next one
 404                          */
 405                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 406                                 continue;
 407
 408                         consume_shallow_list(args, fd[0]);
 409                         do {
 410                                 ack = get_ack(fd[0], result_sha1);
 411                                 if (args->verbose && ack)
 412                                         fprintf(stderr, "got ack %d %s\n", ack,
 413                                                         sha1_to_hex(result_sha1));
 414                                 switch (ack) {
 415                                 case ACK:
 416                                         flushes = 0;
 417                                         multi_ack = 0;
 418                                         retval = 0;
 419                                         goto done;
 420                                 case ACK_common:
 421                                 case ACK_ready:
 422                                 case ACK_continue: {
 423                                         struct commit *commit =
 424                                                 lookup_commit(result_sha1);
 425                                         if (!commit)
 426                                                 die("invalid commit %s", sha1_to_hex(result_sha1));
 427                                         if (args->stateless_rpc
 428                                          && ack == ACK_common
 429                                          && !(commit->object.flags & COMMON)) {
 430                                                 /* We need to replay the have for this object
 431                                                  * on the next RPC request so the peer knows
 432                                                  * it is in common with us.
 433                                                  */
 434                                                 const char *hex = sha1_to_hex(result_sha1);
 435                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 436                                                 state_len = req_buf.len;
 437                                         }
 438                                         mark_common(commit, 0, 1);
 439                                         retval = 0;
 440                                         in_vain = 0;
 441                                         got_continue = 1;
 442                                         if (ack == ACK_ready) {
 443                                                 rev_list = NULL;
 444                                                 got_ready = 1;
 445                                         }
 446                                         break;
 447                                         }
 448                                 }
 449                         } while (ack);
 450                         flushes--;
 451                         if (got_continue && MAX_IN_VAIN < in_vain) {
 452                                 if (args->verbose)
 453                                         fprintf(stderr, "giving up\n");
 454                                 break; /* give up */
 455                         }
 456                 }
 457         }
 458 done:
 459         if (!got_ready || !no_done) {
 460                 packet_buf_write(&req_buf, "done\n");
 461                 send_request(args, fd[1], &req_buf);
 462         }
 463         if (args->verbose)
 464                 fprintf(stderr, "done\n");
 465         if (retval != 0) {
 466                 multi_ack = 0;
 467                 flushes++;
 468         }
 469         strbuf_release(&req_buf);
 470
 471         consume_shallow_list(args, fd[0]);
 472         while (flushes || multi_ack) {
 473                 int ack = get_ack(fd[0], result_sha1);
 474                 if (ack) {
 475                         if (args->verbose)
 476                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 477                                         sha1_to_hex(result_sha1));
 478                         if (ack == ACK)
 479                                 return 0;
 480                         multi_ack = 1;
 481                         continue;
 482                 }
 483                 flushes--;
 484         }
 485         /* it is no error to fetch into a completely empty repo */
 486         return count ? retval : 0;
 487 }
 488
 489 static struct commit_list *complete;
 490
 491 static int mark_complete(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 492 {
 493         struct object *o = parse_object(sha1);
 494
 495         while (o && o->type == OBJ_TAG) {
 496                 struct tag *t = (struct tag *) o;
 497                 if (!t->tagged)
 498                         break; /* broken repository */
 499                 o->flags |= COMPLETE;
 500                 o = parse_object(t->tagged->sha1);
 501         }
 502         if (o && o->type == OBJ_COMMIT) {
 503                 struct commit *commit = (struct commit *)o;
 504                 if (!(commit->object.flags & COMPLETE)) {
 505                         commit->object.flags |= COMPLETE;
 506                         commit_list_insert_by_date(commit, &complete);
 507                 }
 508         }
 509         return 0;
 510 }
 511
 512 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 513                                          unsigned long cutoff)
 514 {
 515         while (complete && cutoff <= complete->item->date) {
 516                 if (args->verbose)
 517                         fprintf(stderr, "Marking %s as complete\n",
 518                                 sha1_to_hex(complete->item->object.sha1));
 519                 pop_most_recent_commit(&complete, COMPLETE);
 520         }
 521 }
 522
 523 static void filter_refs(struct fetch_pack_args *args,
 524                         struct ref **refs,
 525                         struct ref **sought, int nr_sought)
 526 {
 527         struct ref *newlist = NULL;
 528         struct ref **newtail = &newlist;
 529         struct ref *ref, *next;
 530         int i;
 531
 532         i = 0;
 533         for (ref = *refs; ref; ref = next) {
 534                 int keep = 0;
 535                 next = ref->next;
 536
 537                 if (!memcmp(ref->name, "refs/", 5) &&
 538                     check_refname_format(ref->name + 5, 0))
 539                         ; /* trash */
 540                 else {
 541                         while (i < nr_sought) {
 542                                 int cmp = strcmp(ref->name, sought[i]->name);
 543                                 if (cmp < 0)
 544                                         break; /* definitely do not have it */
 545                                 else if (cmp == 0) {
 546                                         keep = 1; /* definitely have it */
 547                                         sought[i]->matched = 1;
 548                                 }
 549                                 i++;
 550                         }
 551                 }
 552
 553                 if (!keep && args->fetch_all &&
 554                     (!args->depth || prefixcmp(ref->name, "refs/tags/")))
 555                         keep = 1;
 556
 557                 if (keep) {
 558                         *newtail = ref;
 559                         ref->next = NULL;
 560                         newtail = &ref->next;
 561                 } else {
 562                         free(ref);
 563                 }
 564         }
 565
 566         /* Append unmatched requests to the list */
 567         if (allow_tip_sha1_in_want) {
 568                 for (i = 0; i < nr_sought; i++) {
 569                         ref = sought[i];
 570                         if (ref->matched)
 571                                 continue;
 572                         if (get_sha1_hex(ref->name, ref->old_sha1))
 573                                 continue;
 574
 575                         ref->matched = 1;
 576                         *newtail = ref;
 577                         ref->next = NULL;
 578                         newtail = &ref->next;
 579                 }
 580         }
 581         *refs = newlist;
 582 }
 583
 584 static void mark_alternate_complete(const struct ref *ref, void *unused)
 585 {
 586         mark_complete(NULL, ref->old_sha1, 0, NULL);
 587 }
 588
 589 static int everything_local(struct fetch_pack_args *args,
 590                             struct ref **refs,
 591                             struct ref **sought, int nr_sought)
 592 {
 593         struct ref *ref;
 594         int retval;
 595         unsigned long cutoff = 0;
 596
 597         save_commit_buffer = 0;
 598
 599         for (ref = *refs; ref; ref = ref->next) {
 600                 struct object *o;
 601
 602                 o = parse_object(ref->old_sha1);
 603                 if (!o)
 604                         continue;
 605
 606                 /* We already have it -- which may mean that we were
 607                  * in sync with the other side at some time after
 608                  * that (it is OK if we guess wrong here).
 609                  */
 610                 if (o->type == OBJ_COMMIT) {
 611                         struct commit *commit = (struct commit *)o;
 612                         if (!cutoff || cutoff < commit->date)
 613                                 cutoff = commit->date;
 614                 }
 615         }
 616
 617         if (!args->depth) {
 618                 for_each_ref(mark_complete, NULL);
 619                 for_each_alternate_ref(mark_alternate_complete, NULL);
 620                 if (cutoff)
 621                         mark_recent_complete_commits(args, cutoff);
 622         }
 623
 624         /*
 625          * Mark all complete remote refs as common refs.
 626          * Don't mark them common yet; the server has to be told so first.
 627          */
 628         for (ref = *refs; ref; ref = ref->next) {
 629                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 630                                              NULL, 0);
 631
 632                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 633                         continue;
 634
 635                 if (!(o->flags & SEEN)) {
 636                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 637
 638                         mark_common((struct commit *)o, 1, 1);
 639                 }
 640         }
 641
 642         filter_refs(args, refs, sought, nr_sought);
 643
 644         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 645                 const unsigned char *remote = ref->old_sha1;
 646                 unsigned char local[20];
 647                 struct object *o;
 648
 649                 o = lookup_object(remote);
 650                 if (!o || !(o->flags & COMPLETE)) {
 651                         retval = 0;
 652                         if (!args->verbose)
 653                                 continue;
 654                         fprintf(stderr,
 655                                 "want %s (%s)\n", sha1_to_hex(remote),
 656                                 ref->name);
 657                         continue;
 658                 }
 659
 660                 hashcpy(ref->new_sha1, local);
 661                 if (!args->verbose)
 662                         continue;
 663                 fprintf(stderr,
 664                         "already have %s (%s)\n", sha1_to_hex(remote),
 665                         ref->name);
 666         }
 667         return retval;
 668 }
 669
 670 static int sideband_demux(int in, int out, void *data)
 671 {
 672         int *xd = data;
 673
 674         int ret = recv_sideband("fetch-pack", xd[0], out);
 675         close(out);
 676         return ret;
 677 }
 678
 679 static int get_pack(struct fetch_pack_args *args,
 680                     int xd[2], char **pack_lockfile)
 681 {
 682         struct async demux;
 683         const char *argv[20];
 684         char keep_arg[256];
 685         char hdr_arg[256];
 686         const char **av;
 687         int do_keep = args->keep_pack;
 688         struct child_process cmd;
 689
 690         memset(&demux, 0, sizeof(demux));
 691         if (use_sideband) {
 692                 /* xd[] is talking with upload-pack; subprocess reads from
 693                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 694                  * through demux->out.
 695                  */
 696                 demux.proc = sideband_demux;
 697                 demux.data = xd;
 698                 demux.out = -1;
 699                 if (start_async(&demux))
 700                         die("fetch-pack: unable to fork off sideband"
 701                             " demultiplexer");
 702         }
 703         else
 704                 demux.out = xd[0];
 705
 706         memset(&cmd, 0, sizeof(cmd));
 707         cmd.argv = argv;
 708         av = argv;
 709         *hdr_arg = 0;
 710         if (!args->keep_pack && unpack_limit) {
 711                 struct pack_header header;
 712
 713                 if (read_pack_header(demux.out, &header))
 714                         die("protocol error: bad pack header");
 715                 snprintf(hdr_arg, sizeof(hdr_arg),
 716                          "--pack_header=%"PRIu32",%"PRIu32,
 717                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 718                 if (ntohl(header.hdr_entries) < unpack_limit)
 719                         do_keep = 0;
 720                 else
 721                         do_keep = 1;
 722         }
 723
 724         if (do_keep) {
 725                 if (pack_lockfile)
 726                         cmd.out = -1;
 727                 *av++ = "index-pack";
 728                 *av++ = "--stdin";
 729                 if (!args->quiet && !args->no_progress)
 730                         *av++ = "-v";
 731                 if (args->use_thin_pack)
 732                         *av++ = "--fix-thin";
 733                 if (args->lock_pack || unpack_limit) {
 734                         int s = sprintf(keep_arg,
 735                                         "--keep=fetch-pack %"PRIuMAX " on ", (uintmax_t) getpid());
 736                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 737                                 strcpy(keep_arg + s, "localhost");
 738                         *av++ = keep_arg;
 739                 }
 740         }
 741         else {
 742                 *av++ = "unpack-objects";
 743                 if (args->quiet || args->no_progress)
 744                         *av++ = "-q";
 745         }
 746         if (*hdr_arg)
 747                 *av++ = hdr_arg;
 748         if (fetch_fsck_objects >= 0
 749             ? fetch_fsck_objects
 750             : transfer_fsck_objects >= 0
 751             ? transfer_fsck_objects
 752             : 0)
 753                 *av++ = "--strict";
 754         *av++ = NULL;
 755
 756         cmd.in = demux.out;
 757         cmd.git_cmd = 1;
 758         if (start_command(&cmd))
 759                 die("fetch-pack: unable to fork off %s", argv[0]);
 760         if (do_keep && pack_lockfile) {
 761                 *pack_lockfile = index_pack_lockfile(cmd.out);
 762                 close(cmd.out);
 763         }
 764
 765         if (finish_command(&cmd))
 766                 die("%s failed", argv[0]);
 767         if (use_sideband && finish_async(&demux))
 768                 die("error in sideband demultiplexer");
 769         return 0;
 770 }
 771
 772 static int cmp_ref_by_name(const void *a_, const void *b_)
 773 {
 774         const struct ref *a = *((const struct ref **)a_);
 775         const struct ref *b = *((const struct ref **)b_);
 776         return strcmp(a->name, b->name);
 777 }
 778
 779 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 780                                  int fd[2],
 781                                  const struct ref *orig_ref,
 782                                  struct ref **sought, int nr_sought,
 783                                  char **pack_lockfile)
 784 {
 785         struct ref *ref = copy_ref_list(orig_ref);
 786         unsigned char sha1[20];
 787         const char *agent_feature;
 788         int agent_len;
 789
 790         sort_ref_list(&ref, ref_compare_name);
 791         qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
 792
 793         if (is_repository_shallow() && !server_supports("shallow"))
 794                 die("Server does not support shallow clients");
 795         if (server_supports("multi_ack_detailed")) {
 796                 if (args->verbose)
 797                         fprintf(stderr, "Server supports multi_ack_detailed\n");
 798                 multi_ack = 2;
 799                 if (server_supports("no-done")) {
 800                         if (args->verbose)
 801                                 fprintf(stderr, "Server supports no-done\n");
 802                         if (args->stateless_rpc)
 803                                 no_done = 1;
 804                 }
 805         }
 806         else if (server_supports("multi_ack")) {
 807                 if (args->verbose)
 808                         fprintf(stderr, "Server supports multi_ack\n");
 809                 multi_ack = 1;
 810         }
 811         if (server_supports("side-band-64k")) {
 812                 if (args->verbose)
 813                         fprintf(stderr, "Server supports side-band-64k\n");
 814                 use_sideband = 2;
 815         }
 816         else if (server_supports("side-band")) {
 817                 if (args->verbose)
 818                         fprintf(stderr, "Server supports side-band\n");
 819                 use_sideband = 1;
 820         }
 821         if (server_supports("allow-tip-sha1-in-want")) {
 822                 if (args->verbose)
 823                         fprintf(stderr, "Server supports allow-tip-sha1-in-want\n");
 824                 allow_tip_sha1_in_want = 1;
 825         }
 826         if (!server_supports("thin-pack"))
 827                 args->use_thin_pack = 0;
 828         if (!server_supports("no-progress"))
 829                 args->no_progress = 0;
 830         if (!server_supports("include-tag"))
 831                 args->include_tag = 0;
 832         if (server_supports("ofs-delta")) {
 833                 if (args->verbose)
 834                         fprintf(stderr, "Server supports ofs-delta\n");
 835         } else
 836                 prefer_ofs_delta = 0;
 837
 838         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 839                 agent_supported = 1;
 840                 if (args->verbose && agent_len)
 841                         fprintf(stderr, "Server version is %.*s\n",
 842                                 agent_len, agent_feature);
 843         }
 844
 845         if (everything_local(args, &ref, sought, nr_sought)) {
 846                 packet_flush(fd[1]);
 847                 goto all_done;
 848         }
 849         if (find_common(args, fd, sha1, ref) < 0)
 850                 if (!args->keep_pack)
 851                         /* When cloning, it is not unusual to have
 852                          * no common commit.
 853                          */
 854                         warning("no common commits");
 855
 856         if (args->stateless_rpc)
 857                 packet_flush(fd[1]);
 858         if (get_pack(args, fd, pack_lockfile))
 859                 die("git fetch-pack: fetch failed.");
 860
 861  all_done:
 862         return ref;
 863 }
 864
 865 static int fetch_pack_config(const char *var, const char *value, void *cb)
 866 {
 867         if (strcmp(var, "fetch.unpacklimit") == 0) {
 868                 fetch_unpack_limit = git_config_int(var, value);
 869                 return 0;
 870         }
 871
 872         if (strcmp(var, "transfer.unpacklimit") == 0) {
 873                 transfer_unpack_limit = git_config_int(var, value);
 874                 return 0;
 875         }
 876
 877         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 878                 prefer_ofs_delta = git_config_bool(var, value);
 879                 return 0;
 880         }
 881
 882         if (!strcmp(var, "fetch.fsckobjects")) {
 883                 fetch_fsck_objects = git_config_bool(var, value);
 884                 return 0;
 885         }
 886
 887         if (!strcmp(var, "transfer.fsckobjects")) {
 888                 transfer_fsck_objects = git_config_bool(var, value);
 889                 return 0;
 890         }
 891
 892         return git_default_config(var, value, cb);
 893 }
 894
 895 static void fetch_pack_setup(void)
 896 {
 897         static int did_setup;
 898         if (did_setup)
 899                 return;
 900         git_config(fetch_pack_config, NULL);
 901         if (0 <= transfer_unpack_limit)
 902                 unpack_limit = transfer_unpack_limit;
 903         else if (0 <= fetch_unpack_limit)
 904                 unpack_limit = fetch_unpack_limit;
 905         did_setup = 1;
 906 }
 907
 908 static int remove_duplicates_in_refs(struct ref **ref, int nr)
 909 {
 910         struct string_list names = STRING_LIST_INIT_NODUP;
 911         int src, dst;
 912
 913         for (src = dst = 0; src < nr; src++) {
 914                 struct string_list_item *item;
 915                 item = string_list_insert(&names, ref[src]->name);
 916                 if (item->util)
 917                         continue; /* already have it */
 918                 item->util = ref[src];
 919                 if (src != dst)
 920                         ref[dst] = ref[src];
 921                 dst++;
 922         }
 923         for (src = dst; src < nr; src++)
 924                 ref[src] = NULL;
 925         string_list_clear(&names, 0);
 926         return dst;
 927 }
 928
 929 struct ref *fetch_pack(struct fetch_pack_args *args,
 930                        int fd[], struct child_process *conn,
 931                        const struct ref *ref,
 932                        const char *dest,
 933                        struct ref **sought, int nr_sought,
 934                        char **pack_lockfile)
 935 {
 936         struct stat st;
 937         struct ref *ref_cpy;
 938
 939         fetch_pack_setup();
 940         if (args->depth > 0) {
 941                 if (stat(git_path("shallow"), &st))
 942                         st.st_mtime = 0;
 943         }
 944
 945         if (nr_sought)
 946                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
 947
 948         if (!ref) {
 949                 packet_flush(fd[1]);
 950                 die("no matching remote head");
 951         }
 952         ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought, pack_lockfile);
 953
 954         if (args->depth > 0) {
 955                 static struct lock_file lock;
 956                 struct cache_time mtime;
 957                 struct strbuf sb = STRBUF_INIT;
 958                 char *shallow = git_path("shallow");
 959                 int fd;
 960
 961                 mtime.sec = st.st_mtime;
 962                 mtime.nsec = ST_MTIME_NSEC(st);
 963                 if (stat(shallow, &st)) {
 964                         if (mtime.sec)
 965                                 die("shallow file was removed during fetch");
 966                 } else if (st.st_mtime != mtime.sec
 967 #ifdef USE_NSEC
 968                                 || ST_MTIME_NSEC(st) != mtime.nsec
 969 #endif
 970                           )
 971                         die("shallow file was changed during fetch");
 972
 973                 fd = hold_lock_file_for_update(&lock, shallow,
 974                                                LOCK_DIE_ON_ERROR);
 975                 if (!write_shallow_commits(&sb, 0)
 976                  || write_in_full(fd, sb.buf, sb.len) != sb.len) {
 977                         unlink_or_warn(shallow);
 978                         rollback_lock_file(&lock);
 979                 } else {
 980                         commit_lock_file(&lock);
 981                 }
 982                 strbuf_release(&sb);
 983         }
 984
 985         reprepare_packed_git();
 986         return ref_cpy;
 987 }