builtin/fetch-pack.c

   1 #include "builtin.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 fetch_pack_args args = {
  24         /* .uploadpack = */ "git-upload-pack",
  25 };
  26
  27 static const char fetch_pack_usage[] =
  28 "git fetch-pack [--all] [--stdin] [--quiet|-q] [--keep|-k] [--thin] "
  29 "[--include-tag] [--upload-pack=<git-upload-pack>] [--depth=<n>] "
  30 "[--no-progress] [-v] [<host>:]<directory> [<refs>...]";
  31
  32 #define COMPLETE        (1U << 0)
  33 #define COMMON          (1U << 1)
  34 #define COMMON_REF      (1U << 2)
  35 #define SEEN            (1U << 3)
  36 #define POPPED          (1U << 4)
  37
  38 static int marked;
  39
  40 /*
  41  * After sending this many "have"s if we do not get any new ACK , we
  42  * give up traversing our history.
  43  */
  44 #define MAX_IN_VAIN 256
  45
  46 static struct commit_list *rev_list;
  47 static int non_common_revs, multi_ack, use_sideband;
  48
  49 static void rev_list_push(struct commit *commit, int mark)
  50 {
  51         if (!(commit->object.flags & mark)) {
  52                 commit->object.flags |= mark;
  53
  54                 if (!(commit->object.parsed))
  55                         if (parse_commit(commit))
  56                                 return;
  57
  58                 commit_list_insert_by_date(commit, &rev_list);
  59
  60                 if (!(commit->object.flags & COMMON))
  61                         non_common_revs++;
  62         }
  63 }
  64
  65 static int rev_list_insert_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  66 {
  67         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  68
  69         if (o && o->type == OBJ_COMMIT)
  70                 rev_list_push((struct commit *)o, SEEN);
  71
  72         return 0;
  73 }
  74
  75 static int clear_marks(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  76 {
  77         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  78
  79         if (o && o->type == OBJ_COMMIT)
  80                 clear_commit_marks((struct commit *)o,
  81                                    COMMON | COMMON_REF | SEEN | POPPED);
  82         return 0;
  83 }
  84
  85 /*
  86    This function marks a rev and its ancestors as common.
  87    In some cases, it is desirable to mark only the ancestors (for example
  88    when only the server does not yet know that they are common).
  89 */
  90
  91 static void mark_common(struct commit *commit,
  92                 int ancestors_only, int dont_parse)
  93 {
  94         if (commit != NULL && !(commit->object.flags & COMMON)) {
  95                 struct object *o = (struct object *)commit;
  96
  97                 if (!ancestors_only)
  98                         o->flags |= COMMON;
  99
 100                 if (!(o->flags & SEEN))
 101                         rev_list_push(commit, SEEN);
 102                 else {
 103                         struct commit_list *parents;
 104
 105                         if (!ancestors_only && !(o->flags & POPPED))
 106                                 non_common_revs--;
 107                         if (!o->parsed && !dont_parse)
 108                                 if (parse_commit(commit))
 109                                         return;
 110
 111                         for (parents = commit->parents;
 112                                         parents;
 113                                         parents = parents->next)
 114                                 mark_common(parents->item, 0, dont_parse);
 115                 }
 116         }
 117 }
 118
 119 /*
 120   Get the next rev to send, ignoring the common.
 121 */
 122
 123 static const unsigned char *get_rev(void)
 124 {
 125         struct commit *commit = NULL;
 126
 127         while (commit == NULL) {
 128                 unsigned int mark;
 129                 struct commit_list *parents;
 130
 131                 if (rev_list == NULL || non_common_revs == 0)
 132                         return NULL;
 133
 134                 commit = rev_list->item;
 135                 if (!commit->object.parsed)
 136                         parse_commit(commit);
 137                 parents = commit->parents;
 138
 139                 commit->object.flags |= POPPED;
 140                 if (!(commit->object.flags & COMMON))
 141                         non_common_revs--;
 142
 143                 if (commit->object.flags & COMMON) {
 144                         /* do not send "have", and ignore ancestors */
 145                         commit = NULL;
 146                         mark = COMMON | SEEN;
 147                 } else if (commit->object.flags & COMMON_REF)
 148                         /* send "have", and ignore ancestors */
 149                         mark = COMMON | SEEN;
 150                 else
 151                         /* send "have", also for its ancestors */
 152                         mark = SEEN;
 153
 154                 while (parents) {
 155                         if (!(parents->item->object.flags & SEEN))
 156                                 rev_list_push(parents->item, mark);
 157                         if (mark & COMMON)
 158                                 mark_common(parents->item, 1, 0);
 159                         parents = parents->next;
 160                 }
 161
 162                 rev_list = rev_list->next;
 163         }
 164
 165         return commit->object.sha1;
 166 }
 167
 168 enum ack_type {
 169         NAK = 0,
 170         ACK,
 171         ACK_continue,
 172         ACK_common,
 173         ACK_ready
 174 };
 175
 176 static void consume_shallow_list(int fd)
 177 {
 178         if (args.stateless_rpc && args.depth > 0) {
 179                 /* If we sent a depth we will get back "duplicate"
 180                  * shallow and unshallow commands every time there
 181                  * is a block of have lines exchanged.
 182                  */
 183                 char line[1000];
 184                 while (packet_read_line(fd, line, sizeof(line))) {
 185                         if (!prefixcmp(line, "shallow "))
 186                                 continue;
 187                         if (!prefixcmp(line, "unshallow "))
 188                                 continue;
 189                         die("git fetch-pack: expected shallow list");
 190                 }
 191         }
 192 }
 193
 194 struct write_shallow_data {
 195         struct strbuf *out;
 196         int use_pack_protocol;
 197         int count;
 198 };
 199
 200 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 201 {
 202         struct write_shallow_data *data = cb_data;
 203         const char *hex = sha1_to_hex(graft->sha1);
 204         data->count++;
 205         if (data->use_pack_protocol)
 206                 packet_buf_write(data->out, "shallow %s", hex);
 207         else {
 208                 strbuf_addstr(data->out, hex);
 209                 strbuf_addch(data->out, '\n');
 210         }
 211         return 0;
 212 }
 213
 214 static int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
 215 {
 216         struct write_shallow_data data;
 217         data.out = out;
 218         data.use_pack_protocol = use_pack_protocol;
 219         data.count = 0;
 220         for_each_commit_graft(write_one_shallow, &data);
 221         return data.count;
 222 }
 223
 224 static enum ack_type get_ack(int fd, unsigned char *result_sha1)
 225 {
 226         static char line[1000];
 227         int len = packet_read_line(fd, line, sizeof(line));
 228
 229         if (!len)
 230                 die("git fetch-pack: expected ACK/NAK, got EOF");
 231         if (line[len-1] == '\n')
 232                 line[--len] = 0;
 233         if (!strcmp(line, "NAK"))
 234                 return NAK;
 235         if (!prefixcmp(line, "ACK ")) {
 236                 if (!get_sha1_hex(line+4, result_sha1)) {
 237                         if (strstr(line+45, "continue"))
 238                                 return ACK_continue;
 239                         if (strstr(line+45, "common"))
 240                                 return ACK_common;
 241                         if (strstr(line+45, "ready"))
 242                                 return ACK_ready;
 243                         return ACK;
 244                 }
 245         }
 246         die("git fetch_pack: expected ACK/NAK, got '%s'", line);
 247 }
 248
 249 static void send_request(int fd, struct strbuf *buf)
 250 {
 251         if (args.stateless_rpc) {
 252                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 253                 packet_flush(fd);
 254         } else
 255                 safe_write(fd, buf->buf, buf->len);
 256 }
 257
 258 static void insert_one_alternate_ref(const struct ref *ref, void *unused)
 259 {
 260         rev_list_insert_ref(NULL, ref->old_sha1, 0, NULL);
 261 }
 262
 263 #define INITIAL_FLUSH 16
 264 #define PIPESAFE_FLUSH 32
 265 #define LARGE_FLUSH 1024
 266
 267 static int next_flush(int count)
 268 {
 269         int flush_limit = args.stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
 270
 271         if (count < flush_limit)
 272                 count <<= 1;
 273         else
 274                 count += flush_limit;
 275         return count;
 276 }
 277
 278 static int find_common(int fd[2], unsigned char *result_sha1,
 279                        struct ref *refs)
 280 {
 281         int fetching;
 282         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 283         const unsigned char *sha1;
 284         unsigned in_vain = 0;
 285         int got_continue = 0;
 286         int got_ready = 0;
 287         struct strbuf req_buf = STRBUF_INIT;
 288         size_t state_len = 0;
 289
 290         if (args.stateless_rpc && multi_ack == 1)
 291                 die("--stateless-rpc requires multi_ack_detailed");
 292         if (marked)
 293                 for_each_ref(clear_marks, NULL);
 294         marked = 1;
 295
 296         for_each_ref(rev_list_insert_ref, NULL);
 297         for_each_alternate_ref(insert_one_alternate_ref, NULL);
 298
 299         fetching = 0;
 300         for ( ; refs ; refs = refs->next) {
 301                 unsigned char *remote = refs->old_sha1;
 302                 const char *remote_hex;
 303                 struct object *o;
 304
 305                 /*
 306                  * If that object is complete (i.e. it is an ancestor of a
 307                  * local ref), we tell them we have it but do not have to
 308                  * tell them about its ancestors, which they already know
 309                  * about.
 310                  *
 311                  * We use lookup_object here because we are only
 312                  * interested in the case we *know* the object is
 313                  * reachable and we have already scanned it.
 314                  */
 315                 if (((o = lookup_object(remote)) != NULL) &&
 316                                 (o->flags & COMPLETE)) {
 317                         continue;
 318                 }
 319
 320                 remote_hex = sha1_to_hex(remote);
 321                 if (!fetching) {
 322                         struct strbuf c = STRBUF_INIT;
 323                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 324                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 325                         if (no_done)            strbuf_addstr(&c, " no-done");
 326                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 327                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 328                         if (args.use_thin_pack) strbuf_addstr(&c, " thin-pack");
 329                         if (args.no_progress)   strbuf_addstr(&c, " no-progress");
 330                         if (args.include_tag)   strbuf_addstr(&c, " include-tag");
 331                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 332                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 333                                                             git_user_agent_sanitized());
 334                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 335                         strbuf_release(&c);
 336                 } else
 337                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 338                 fetching++;
 339         }
 340
 341         if (!fetching) {
 342                 strbuf_release(&req_buf);
 343                 packet_flush(fd[1]);
 344                 return 1;
 345         }
 346
 347         if (is_repository_shallow())
 348                 write_shallow_commits(&req_buf, 1);
 349         if (args.depth > 0)
 350                 packet_buf_write(&req_buf, "deepen %d", args.depth);
 351         packet_buf_flush(&req_buf);
 352         state_len = req_buf.len;
 353
 354         if (args.depth > 0) {
 355                 char line[1024];
 356                 unsigned char sha1[20];
 357
 358                 send_request(fd[1], &req_buf);
 359                 while (packet_read_line(fd[0], line, sizeof(line))) {
 360                         if (!prefixcmp(line, "shallow ")) {
 361                                 if (get_sha1_hex(line + 8, sha1))
 362                                         die("invalid shallow line: %s", line);
 363                                 register_shallow(sha1);
 364                                 continue;
 365                         }
 366                         if (!prefixcmp(line, "unshallow ")) {
 367                                 if (get_sha1_hex(line + 10, sha1))
 368                                         die("invalid unshallow line: %s", line);
 369                                 if (!lookup_object(sha1))
 370                                         die("object not found: %s", line);
 371                                 /* make sure that it is parsed as shallow */
 372                                 if (!parse_object(sha1))
 373                                         die("error in object: %s", line);
 374                                 if (unregister_shallow(sha1))
 375                                         die("no shallow found: %s", line);
 376                                 continue;
 377                         }
 378                         die("expected shallow/unshallow, got %s", line);
 379                 }
 380         } else if (!args.stateless_rpc)
 381                 send_request(fd[1], &req_buf);
 382
 383         if (!args.stateless_rpc) {
 384                 /* If we aren't using the stateless-rpc interface
 385                  * we don't need to retain the headers.
 386                  */
 387                 strbuf_setlen(&req_buf, 0);
 388                 state_len = 0;
 389         }
 390
 391         flushes = 0;
 392         retval = -1;
 393         while ((sha1 = get_rev())) {
 394                 packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
 395                 if (args.verbose)
 396                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 397                 in_vain++;
 398                 if (flush_at <= ++count) {
 399                         int ack;
 400
 401                         packet_buf_flush(&req_buf);
 402                         send_request(fd[1], &req_buf);
 403                         strbuf_setlen(&req_buf, state_len);
 404                         flushes++;
 405                         flush_at = next_flush(count);
 406
 407                         /*
 408                          * We keep one window "ahead" of the other side, and
 409                          * will wait for an ACK only on the next one
 410                          */
 411                         if (!args.stateless_rpc && count == INITIAL_FLUSH)
 412                                 continue;
 413
 414                         consume_shallow_list(fd[0]);
 415                         do {
 416                                 ack = get_ack(fd[0], result_sha1);
 417                                 if (args.verbose && ack)
 418                                         fprintf(stderr, "got ack %d %s\n", ack,
 419                                                         sha1_to_hex(result_sha1));
 420                                 switch (ack) {
 421                                 case ACK:
 422                                         flushes = 0;
 423                                         multi_ack = 0;
 424                                         retval = 0;
 425                                         goto done;
 426                                 case ACK_common:
 427                                 case ACK_ready:
 428                                 case ACK_continue: {
 429                                         struct commit *commit =
 430                                                 lookup_commit(result_sha1);
 431                                         if (!commit)
 432                                                 die("invalid commit %s", sha1_to_hex(result_sha1));
 433                                         if (args.stateless_rpc
 434                                          && ack == ACK_common
 435                                          && !(commit->object.flags & COMMON)) {
 436                                                 /* We need to replay the have for this object
 437                                                  * on the next RPC request so the peer knows
 438                                                  * it is in common with us.
 439                                                  */
 440                                                 const char *hex = sha1_to_hex(result_sha1);
 441                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 442                                                 state_len = req_buf.len;
 443                                         }
 444                                         mark_common(commit, 0, 1);
 445                                         retval = 0;
 446                                         in_vain = 0;
 447                                         got_continue = 1;
 448                                         if (ack == ACK_ready) {
 449                                                 rev_list = NULL;
 450                                                 got_ready = 1;
 451                                         }
 452                                         break;
 453                                         }
 454                                 }
 455                         } while (ack);
 456                         flushes--;
 457                         if (got_continue && MAX_IN_VAIN < in_vain) {
 458                                 if (args.verbose)
 459                                         fprintf(stderr, "giving up\n");
 460                                 break; /* give up */
 461                         }
 462                 }
 463         }
 464 done:
 465         if (!got_ready || !no_done) {
 466                 packet_buf_write(&req_buf, "done\n");
 467                 send_request(fd[1], &req_buf);
 468         }
 469         if (args.verbose)
 470                 fprintf(stderr, "done\n");
 471         if (retval != 0) {
 472                 multi_ack = 0;
 473                 flushes++;
 474         }
 475         strbuf_release(&req_buf);
 476
 477         consume_shallow_list(fd[0]);
 478         while (flushes || multi_ack) {
 479                 int ack = get_ack(fd[0], result_sha1);
 480                 if (ack) {
 481                         if (args.verbose)
 482                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 483                                         sha1_to_hex(result_sha1));
 484                         if (ack == ACK)
 485                                 return 0;
 486                         multi_ack = 1;
 487                         continue;
 488                 }
 489                 flushes--;
 490         }
 491         /* it is no error to fetch into a completely empty repo */
 492         return count ? retval : 0;
 493 }
 494
 495 static struct commit_list *complete;
 496
 497 static int mark_complete(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 498 {
 499         struct object *o = parse_object(sha1);
 500
 501         while (o && o->type == OBJ_TAG) {
 502                 struct tag *t = (struct tag *) o;
 503                 if (!t->tagged)
 504                         break; /* broken repository */
 505                 o->flags |= COMPLETE;
 506                 o = parse_object(t->tagged->sha1);
 507         }
 508         if (o && o->type == OBJ_COMMIT) {
 509                 struct commit *commit = (struct commit *)o;
 510                 if (!(commit->object.flags & COMPLETE)) {
 511                         commit->object.flags |= COMPLETE;
 512                         commit_list_insert_by_date(commit, &complete);
 513                 }
 514         }
 515         return 0;
 516 }
 517
 518 static void mark_recent_complete_commits(unsigned long cutoff)
 519 {
 520         while (complete && cutoff <= complete->item->date) {
 521                 if (args.verbose)
 522                         fprintf(stderr, "Marking %s as complete\n",
 523                                 sha1_to_hex(complete->item->object.sha1));
 524                 pop_most_recent_commit(&complete, COMPLETE);
 525         }
 526 }
 527
 528 static void filter_refs(struct ref **refs, int nr_match, char **match)
 529 {
 530         struct ref **return_refs;
 531         struct ref *newlist = NULL;
 532         struct ref **newtail = &newlist;
 533         struct ref *ref, *next;
 534         struct ref *fastarray[32];
 535         int match_pos;
 536
 537         if (nr_match && !args.fetch_all) {
 538                 if (ARRAY_SIZE(fastarray) < nr_match)
 539                         return_refs = xcalloc(nr_match, sizeof(struct ref *));
 540                 else {
 541                         return_refs = fastarray;
 542                         memset(return_refs, 0, sizeof(struct ref *) * nr_match);
 543                 }
 544         }
 545         else
 546                 return_refs = NULL;
 547
 548         match_pos = 0;
 549         for (ref = *refs; ref; ref = next) {
 550                 next = ref->next;
 551                 if (!memcmp(ref->name, "refs/", 5) &&
 552                     check_refname_format(ref->name + 5, 0))
 553                         ; /* trash */
 554                 else if (args.fetch_all &&
 555                          (!args.depth || prefixcmp(ref->name, "refs/tags/") )) {
 556                         *newtail = ref;
 557                         ref->next = NULL;
 558                         newtail = &ref->next;
 559                         continue;
 560                 }
 561                 else {
 562                         int cmp = -1;
 563                         while (match_pos < nr_match) {
 564                                 cmp = strcmp(ref->name, match[match_pos]);
 565                                 if (cmp < 0) /* definitely do not have it */
 566                                         break;
 567                                 else if (cmp == 0) { /* definitely have it */
 568                                         match[match_pos][0] = '\0';
 569                                         return_refs[match_pos] = ref;
 570                                         break;
 571                                 }
 572                                 else /* might have it; keep looking */
 573                                         match_pos++;
 574                         }
 575                         if (!cmp)
 576                                 continue; /* we will link it later */
 577                 }
 578                 free(ref);
 579         }
 580
 581         if (!args.fetch_all) {
 582                 int i;
 583                 for (i = 0; i < nr_match; i++) {
 584                         ref = return_refs[i];
 585                         if (ref) {
 586                                 *newtail = ref;
 587                                 ref->next = NULL;
 588                                 newtail = &ref->next;
 589                         }
 590                 }
 591                 if (return_refs != fastarray)
 592                         free(return_refs);
 593         }
 594         *refs = newlist;
 595 }
 596
 597 static void mark_alternate_complete(const struct ref *ref, void *unused)
 598 {
 599         mark_complete(NULL, ref->old_sha1, 0, NULL);
 600 }
 601
 602 static int everything_local(struct ref **refs, int nr_match, char **match)
 603 {
 604         struct ref *ref;
 605         int retval;
 606         unsigned long cutoff = 0;
 607
 608         save_commit_buffer = 0;
 609
 610         for (ref = *refs; ref; ref = ref->next) {
 611                 struct object *o;
 612
 613                 o = parse_object(ref->old_sha1);
 614                 if (!o)
 615                         continue;
 616
 617                 /* We already have it -- which may mean that we were
 618                  * in sync with the other side at some time after
 619                  * that (it is OK if we guess wrong here).
 620                  */
 621                 if (o->type == OBJ_COMMIT) {
 622                         struct commit *commit = (struct commit *)o;
 623                         if (!cutoff || cutoff < commit->date)
 624                                 cutoff = commit->date;
 625                 }
 626         }
 627
 628         if (!args.depth) {
 629                 for_each_ref(mark_complete, NULL);
 630                 for_each_alternate_ref(mark_alternate_complete, NULL);
 631                 if (cutoff)
 632                         mark_recent_complete_commits(cutoff);
 633         }
 634
 635         /*
 636          * Mark all complete remote refs as common refs.
 637          * Don't mark them common yet; the server has to be told so first.
 638          */
 639         for (ref = *refs; ref; ref = ref->next) {
 640                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 641                                              NULL, 0);
 642
 643                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 644                         continue;
 645
 646                 if (!(o->flags & SEEN)) {
 647                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 648
 649                         mark_common((struct commit *)o, 1, 1);
 650                 }
 651         }
 652
 653         filter_refs(refs, nr_match, match);
 654
 655         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 656                 const unsigned char *remote = ref->old_sha1;
 657                 unsigned char local[20];
 658                 struct object *o;
 659
 660                 o = lookup_object(remote);
 661                 if (!o || !(o->flags & COMPLETE)) {
 662                         retval = 0;
 663                         if (!args.verbose)
 664                                 continue;
 665                         fprintf(stderr,
 666                                 "want %s (%s)\n", sha1_to_hex(remote),
 667                                 ref->name);
 668                         continue;
 669                 }
 670
 671                 hashcpy(ref->new_sha1, local);
 672                 if (!args.verbose)
 673                         continue;
 674                 fprintf(stderr,
 675                         "already have %s (%s)\n", sha1_to_hex(remote),
 676                         ref->name);
 677         }
 678         return retval;
 679 }
 680
 681 static int sideband_demux(int in, int out, void *data)
 682 {
 683         int *xd = data;
 684
 685         int ret = recv_sideband("fetch-pack", xd[0], out);
 686         close(out);
 687         return ret;
 688 }
 689
 690 static int get_pack(int xd[2], char **pack_lockfile)
 691 {
 692         struct async demux;
 693         const char *argv[20];
 694         char keep_arg[256];
 695         char hdr_arg[256];
 696         const char **av;
 697         int do_keep = args.keep_pack;
 698         struct child_process cmd;
 699
 700         memset(&demux, 0, sizeof(demux));
 701         if (use_sideband) {
 702                 /* xd[] is talking with upload-pack; subprocess reads from
 703                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 704                  * through demux->out.
 705                  */
 706                 demux.proc = sideband_demux;
 707                 demux.data = xd;
 708                 demux.out = -1;
 709                 if (start_async(&demux))
 710                         die("fetch-pack: unable to fork off sideband"
 711                             " demultiplexer");
 712         }
 713         else
 714                 demux.out = xd[0];
 715
 716         memset(&cmd, 0, sizeof(cmd));
 717         cmd.argv = argv;
 718         av = argv;
 719         *hdr_arg = 0;
 720         if (!args.keep_pack && unpack_limit) {
 721                 struct pack_header header;
 722
 723                 if (read_pack_header(demux.out, &header))
 724                         die("protocol error: bad pack header");
 725                 snprintf(hdr_arg, sizeof(hdr_arg),
 726                          "--pack_header=%"PRIu32",%"PRIu32,
 727                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 728                 if (ntohl(header.hdr_entries) < unpack_limit)
 729                         do_keep = 0;
 730                 else
 731                         do_keep = 1;
 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 struct ref *do_fetch_pack(int fd[2],
 783                 const struct ref *orig_ref,
 784                 int nr_match,
 785                 char **match,
 786                 char **pack_lockfile)
 787 {
 788         struct ref *ref = copy_ref_list(orig_ref);
 789         unsigned char sha1[20];
 790         const char *agent_feature;
 791         int agent_len;
 792
 793         sort_ref_list(&ref, ref_compare_name);
 794
 795         if (is_repository_shallow() && !server_supports("shallow"))
 796                 die("Server does not support shallow clients");
 797         if (server_supports("multi_ack_detailed")) {
 798                 if (args.verbose)
 799                         fprintf(stderr, "Server supports multi_ack_detailed\n");
 800                 multi_ack = 2;
 801                 if (server_supports("no-done")) {
 802                         if (args.verbose)
 803                                 fprintf(stderr, "Server supports no-done\n");
 804                         if (args.stateless_rpc)
 805                                 no_done = 1;
 806                 }
 807         }
 808         else if (server_supports("multi_ack")) {
 809                 if (args.verbose)
 810                         fprintf(stderr, "Server supports multi_ack\n");
 811                 multi_ack = 1;
 812         }
 813         if (server_supports("side-band-64k")) {
 814                 if (args.verbose)
 815                         fprintf(stderr, "Server supports side-band-64k\n");
 816                 use_sideband = 2;
 817         }
 818         else if (server_supports("side-band")) {
 819                 if (args.verbose)
 820                         fprintf(stderr, "Server supports side-band\n");
 821                 use_sideband = 1;
 822         }
 823         if (!server_supports("thin-pack"))
 824                 args.use_thin_pack = 0;
 825         if (!server_supports("no-progress"))
 826                 args.no_progress = 0;
 827         if (!server_supports("include-tag"))
 828                 args.include_tag = 0;
 829         if (server_supports("ofs-delta")) {
 830                 if (args.verbose)
 831                         fprintf(stderr, "Server supports ofs-delta\n");
 832         } else
 833                 prefer_ofs_delta = 0;
 834
 835         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 836                 agent_supported = 1;
 837                 if (args.verbose && agent_len)
 838                         fprintf(stderr, "Server version is %.*s\n",
 839                                 agent_len, agent_feature);
 840         }
 841
 842         if (everything_local(&ref, nr_match, match)) {
 843                 packet_flush(fd[1]);
 844                 goto all_done;
 845         }
 846         if (find_common(fd, sha1, ref) < 0)
 847                 if (!args.keep_pack)
 848                         /* When cloning, it is not unusual to have
 849                          * no common commit.
 850                          */
 851                         warning("no common commits");
 852
 853         if (args.stateless_rpc)
 854                 packet_flush(fd[1]);
 855         if (get_pack(fd, pack_lockfile))
 856                 die("git fetch-pack: fetch failed.");
 857
 858  all_done:
 859         return ref;
 860 }
 861
 862 static int remove_duplicates(int nr_heads, char **heads)
 863 {
 864         int src, dst;
 865
 866         if (!nr_heads)
 867                 return 0;
 868
 869         for (src = dst = 1; src < nr_heads; src++)
 870                 if (strcmp(heads[src], heads[dst-1]))
 871                         heads[dst++] = heads[src];
 872         return dst;
 873 }
 874
 875 static int fetch_pack_config(const char *var, const char *value, void *cb)
 876 {
 877         if (strcmp(var, "fetch.unpacklimit") == 0) {
 878                 fetch_unpack_limit = git_config_int(var, value);
 879                 return 0;
 880         }
 881
 882         if (strcmp(var, "transfer.unpacklimit") == 0) {
 883                 transfer_unpack_limit = git_config_int(var, value);
 884                 return 0;
 885         }
 886
 887         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 888                 prefer_ofs_delta = git_config_bool(var, value);
 889                 return 0;
 890         }
 891
 892         if (!strcmp(var, "fetch.fsckobjects")) {
 893                 fetch_fsck_objects = git_config_bool(var, value);
 894                 return 0;
 895         }
 896
 897         if (!strcmp(var, "transfer.fsckobjects")) {
 898                 transfer_fsck_objects = git_config_bool(var, value);
 899                 return 0;
 900         }
 901
 902         return git_default_config(var, value, cb);
 903 }
 904
 905 static struct lock_file lock;
 906
 907 static void fetch_pack_setup(void)
 908 {
 909         static int did_setup;
 910         if (did_setup)
 911                 return;
 912         git_config(fetch_pack_config, NULL);
 913         if (0 <= transfer_unpack_limit)
 914                 unpack_limit = transfer_unpack_limit;
 915         else if (0 <= fetch_unpack_limit)
 916                 unpack_limit = fetch_unpack_limit;
 917         did_setup = 1;
 918 }
 919
 920 int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 921 {
 922         int i, ret;
 923         struct ref *ref = NULL;
 924         const char *dest = NULL;
 925         int alloc_heads = 0, nr_heads = 0;
 926         char **heads = NULL;
 927         int fd[2];
 928         char *pack_lockfile = NULL;
 929         char **pack_lockfile_ptr = NULL;
 930         struct child_process *conn;
 931
 932         packet_trace_identity("fetch-pack");
 933
 934         for (i = 1; i < argc && *argv[i] == '-'; i++) {
 935                 const char *arg = argv[i];
 936
 937                 if (!prefixcmp(arg, "--upload-pack=")) {
 938                         args.uploadpack = arg + 14;
 939                         continue;
 940                 }
 941                 if (!prefixcmp(arg, "--exec=")) {
 942                         args.uploadpack = arg + 7;
 943                         continue;
 944                 }
 945                 if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
 946                         args.quiet = 1;
 947                         continue;
 948                 }
 949                 if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
 950                         args.lock_pack = args.keep_pack;
 951                         args.keep_pack = 1;
 952                         continue;
 953                 }
 954                 if (!strcmp("--thin", arg)) {
 955                         args.use_thin_pack = 1;
 956                         continue;
 957                 }
 958                 if (!strcmp("--include-tag", arg)) {
 959                         args.include_tag = 1;
 960                         continue;
 961                 }
 962                 if (!strcmp("--all", arg)) {
 963                         args.fetch_all = 1;
 964                         continue;
 965                 }
 966                 if (!strcmp("--stdin", arg)) {
 967                         args.stdin_refs = 1;
 968                         continue;
 969                 }
 970                 if (!strcmp("-v", arg)) {
 971                         args.verbose = 1;
 972                         continue;
 973                 }
 974                 if (!prefixcmp(arg, "--depth=")) {
 975                         args.depth = strtol(arg + 8, NULL, 0);
 976                         continue;
 977                 }
 978                 if (!strcmp("--no-progress", arg)) {
 979                         args.no_progress = 1;
 980                         continue;
 981                 }
 982                 if (!strcmp("--stateless-rpc", arg)) {
 983                         args.stateless_rpc = 1;
 984                         continue;
 985                 }
 986                 if (!strcmp("--lock-pack", arg)) {
 987                         args.lock_pack = 1;
 988                         pack_lockfile_ptr = &pack_lockfile;
 989                         continue;
 990                 }
 991                 usage(fetch_pack_usage);
 992         }
 993
 994         if (i < argc)
 995                 dest = argv[i++];
 996         else
 997                 usage(fetch_pack_usage);
 998
 999         /*
1000          * Copy refs from cmdline to growable list, then append any
1001          * refs from the standard input:
1002          */
1003         ALLOC_GROW(heads, argc - i, alloc_heads);
1004         for (; i < argc; i++)
1005                 heads[nr_heads++] = xstrdup(argv[i]);
1006         if (args.stdin_refs) {
1007                 if (args.stateless_rpc) {
1008                         /* in stateless RPC mode we use pkt-line to read
1009                          * from stdin, until we get a flush packet
1010                          */
1011                         static char line[1000];
1012                         for (;;) {
1013                                 int n = packet_read_line(0, line, sizeof(line));
1014                                 if (!n)
1015                                         break;
1016                                 if (line[n-1] == '\n')
1017                                         n--;
1018                                 ALLOC_GROW(heads, nr_heads + 1, alloc_heads);
1019                                 heads[nr_heads++] = xmemdupz(line, n);
1020                         }
1021                 }
1022                 else {
1023                         /* read from stdin one ref per line, until EOF */
1024                         struct strbuf line = STRBUF_INIT;
1025                         while (strbuf_getline(&line, stdin, '\n') != EOF) {
1026                                 ALLOC_GROW(heads, nr_heads + 1, alloc_heads);
1027                                 heads[nr_heads++] = strbuf_detach(&line, NULL);
1028                         }
1029                         strbuf_release(&line);
1030                 }
1031         }
1032
1033         if (args.stateless_rpc) {
1034                 conn = NULL;
1035                 fd[0] = 0;
1036                 fd[1] = 1;
1037         } else {
1038                 conn = git_connect(fd, dest, args.uploadpack,
1039                                    args.verbose ? CONNECT_VERBOSE : 0);
1040         }
1041
1042         get_remote_heads(fd[0], &ref, 0, NULL);
1043
1044         ref = fetch_pack(&args, fd, conn, ref, dest,
1045                 nr_heads, heads, pack_lockfile_ptr);
1046         if (pack_lockfile) {
1047                 printf("lock %s\n", pack_lockfile);
1048                 fflush(stdout);
1049         }
1050         close(fd[0]);
1051         close(fd[1]);
1052         if (finish_connect(conn))
1053                 ref = NULL;
1054         ret = !ref;
1055
1056         if (!ret && nr_heads) {
1057                 /* If the heads to pull were given, we should have
1058                  * consumed all of them by matching the remote.
1059                  * Otherwise, 'git fetch remote no-such-ref' would
1060                  * silently succeed without issuing an error.
1061                  */
1062                 for (i = 0; i < nr_heads; i++)
1063                         if (heads[i] && heads[i][0]) {
1064                                 error("no such remote ref %s", heads[i]);
1065                                 ret = 1;
1066                         }
1067         }
1068         while (ref) {
1069                 printf("%s %s\n",
1070                        sha1_to_hex(ref->old_sha1), ref->name);
1071                 ref = ref->next;
1072         }
1073
1074         return ret;
1075 }
1076
1077 static int compare_heads(const void *a, const void *b)
1078 {
1079         return strcmp(*(const char **)a, *(const char **)b);
1080 }
1081
1082 struct ref *fetch_pack(struct fetch_pack_args *my_args,
1083                        int fd[], struct child_process *conn,
1084                        const struct ref *ref,
1085                 const char *dest,
1086                 int nr_heads,
1087                 char **heads,
1088                 char **pack_lockfile)
1089 {
1090         struct stat st;
1091         struct ref *ref_cpy;
1092
1093         fetch_pack_setup();
1094         if (&args != my_args)
1095                 memcpy(&args, my_args, sizeof(args));
1096         if (args.depth > 0) {
1097                 if (stat(git_path("shallow"), &st))
1098                         st.st_mtime = 0;
1099         }
1100
1101         if (heads && nr_heads) {
1102                 qsort(heads, nr_heads, sizeof(*heads), compare_heads);
1103                 nr_heads = remove_duplicates(nr_heads, heads);
1104         }
1105
1106         if (!ref) {
1107                 packet_flush(fd[1]);
1108                 die("no matching remote head");
1109         }
1110         ref_cpy = do_fetch_pack(fd, ref, nr_heads, heads, pack_lockfile);
1111
1112         if (args.depth > 0) {
1113                 struct cache_time mtime;
1114                 struct strbuf sb = STRBUF_INIT;
1115                 char *shallow = git_path("shallow");
1116                 int fd;
1117
1118                 mtime.sec = st.st_mtime;
1119                 mtime.nsec = ST_MTIME_NSEC(st);
1120                 if (stat(shallow, &st)) {
1121                         if (mtime.sec)
1122                                 die("shallow file was removed during fetch");
1123                 } else if (st.st_mtime != mtime.sec
1124 #ifdef USE_NSEC
1125                                 || ST_MTIME_NSEC(st) != mtime.nsec
1126 #endif
1127                           )
1128                         die("shallow file was changed during fetch");
1129
1130                 fd = hold_lock_file_for_update(&lock, shallow,
1131                                                LOCK_DIE_ON_ERROR);
1132                 if (!write_shallow_commits(&sb, 0)
1133                  || write_in_full(fd, sb.buf, sb.len) != sb.len) {
1134                         unlink_or_warn(shallow);
1135                         rollback_lock_file(&lock);
1136                 } else {
1137                         commit_lock_file(&lock);
1138                 }
1139                 strbuf_release(&sb);
1140         }
1141
1142         reprepare_packed_git();
1143         return ref_cpy;
1144 }