upload-pack.c

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