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         return 0;
 136 }
 137
 138 static void create_pack_file(void)
 139 {
 140         struct async rev_list;
 141         struct child_process pack_objects;
 142         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
 143         char data[8193], progress[128];
 144         char abort_msg[] = "aborting due to possible repository "
 145                 "corruption on the remote side.";
 146         int buffered = -1;
 147         const char *argv[10];
 148         int arg = 0;
 149
 150         rev_list.proc = do_rev_list;
 151         /* .data is just a boolean: any non-NULL value will do */
 152         rev_list.data = create_full_pack ? &rev_list : NULL;
 153         if (start_async(&rev_list))
 154                 die("git-upload-pack: unable to fork git-rev-list");
 155
 156         argv[arg++] = "pack-objects";
 157         argv[arg++] = "--stdout";
 158         if (!no_progress)
 159                 argv[arg++] = "--progress";
 160         if (use_ofs_delta)
 161                 argv[arg++] = "--delta-base-offset";
 162         argv[arg++] = NULL;
 163
 164         memset(&pack_objects, 0, sizeof(pack_objects));
 165         pack_objects.in = rev_list.out; /* start_command closes it */
 166         pack_objects.out = -1;
 167         pack_objects.err = -1;
 168         pack_objects.git_cmd = 1;
 169         pack_objects.argv = argv;
 170
 171         if (start_command(&pack_objects)) {
 172                 /* daemon sets things up to ignore TERM */
 173                 kill(rev_list.pid, SIGKILL);
 174                 die("git-upload-pack: unable to fork git-pack-objects");
 175         }
 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                 const char *who;
 183                 struct pollfd pfd[2];
 184                 pid_t pid;
 185                 int status;
 186                 ssize_t sz;
 187                 int pe, pu, pollsize;
 188
 189                 reset_timeout();
 190
 191                 pollsize = 0;
 192                 pe = pu = -1;
 193
 194                 if (0 <= pack_objects.out) {
 195                         pfd[pollsize].fd = pack_objects.out;
 196                         pfd[pollsize].events = POLLIN;
 197                         pu = pollsize;
 198                         pollsize++;
 199                 }
 200                 if (0 <= pack_objects.err) {
 201                         pfd[pollsize].fd = pack_objects.err;
 202                         pfd[pollsize].events = POLLIN;
 203                         pe = pollsize;
 204                         pollsize++;
 205                 }
 206
 207                 if (pollsize) {
 208                         if (poll(pfd, pollsize, -1) < 0) {
 209                                 if (errno != EINTR) {
 210                                         error("poll failed, resuming: %s",
 211                                               strerror(errno));
 212                                         sleep(1);
 213                                 }
 214                                 continue;
 215                         }
 216                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 217                                 /* Data ready; we keep the last byte
 218                                  * to ourselves in case we detect
 219                                  * broken rev-list, so that we can
 220                                  * leave the stream corrupted.  This
 221                                  * is unfortunate -- unpack-objects
 222                                  * would happily accept a valid pack
 223                                  * data with trailing garbage, so
 224                                  * appending garbage after we pass all
 225                                  * the pack data is not good enough to
 226                                  * signal breakage to downstream.
 227                                  */
 228                                 char *cp = data;
 229                                 ssize_t outsz = 0;
 230                                 if (0 <= buffered) {
 231                                         *cp++ = buffered;
 232                                         outsz++;
 233                                 }
 234                                 sz = xread(pack_objects.out, cp,
 235                                           sizeof(data) - outsz);
 236                                 if (0 < sz)
 237                                                 ;
 238                                 else if (sz == 0) {
 239                                         close(pack_objects.out);
 240                                         pack_objects.out = -1;
 241                                 }
 242                                 else
 243                                         goto fail;
 244                                 sz += outsz;
 245                                 if (1 < sz) {
 246                                         buffered = data[sz-1] & 0xFF;
 247                                         sz--;
 248                                 }
 249                                 else
 250                                         buffered = -1;
 251                                 sz = send_client_data(1, data, sz);
 252                                 if (sz < 0)
 253                                         goto fail;
 254                         }
 255                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 256                                 /* Status ready; we ship that in the side-band
 257                                  * or dump to the standard error.
 258                                  */
 259                                 sz = xread(pack_objects.err, progress,
 260                                           sizeof(progress));
 261                                 if (0 < sz)
 262                                         send_client_data(2, progress, sz);
 263                                 else if (sz == 0) {
 264                                         close(pack_objects.err);
 265                                         pack_objects.err = -1;
 266                                 }
 267                                 else
 268                                         goto fail;
 269                         }
 270                 }
 271
 272                 /* See if the children are still there */
 273                 if (rev_list.pid || pack_objects.pid) {
 274                         pid = waitpid(-1, &status, WNOHANG);
 275                         if (!pid)
 276                                 continue;
 277                         who = ((pid == rev_list.pid) ? "git-rev-list" :
 278                                (pid == pack_objects.pid) ? "git-pack-objects" :
 279                                NULL);
 280                         if (!who) {
 281                                 if (pid < 0) {
 282                                         error("git-upload-pack: %s",
 283                                               strerror(errno));
 284                                         goto fail;
 285                                 }
 286                                 error("git-upload-pack: we weren't "
 287                                       "waiting for %d", pid);
 288                                 continue;
 289                         }
 290                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 291                                 error("git-upload-pack: %s died with error.",
 292                                       who);
 293                                 goto fail;
 294                         }
 295                         if (pid == rev_list.pid)
 296                                 rev_list.pid = 0;
 297                         if (pid == pack_objects.pid)
 298                                 pack_objects.pid = 0;
 299                         if (rev_list.pid || pack_objects.pid)
 300                                 continue;
 301                 }
 302
 303                 /* both died happily */
 304                 if (pollsize)
 305                         continue;
 306
 307                 /* flush the data */
 308                 if (0 <= buffered) {
 309                         data[0] = buffered;
 310                         sz = send_client_data(1, data, 1);
 311                         if (sz < 0)
 312                                 goto fail;
 313                         fprintf(stderr, "flushed.\n");
 314                 }
 315                 if (use_sideband)
 316                         packet_flush(1);
 317                 return;
 318         }
 319  fail:
 320         if (pack_objects.pid)
 321                 kill(pack_objects.pid, SIGKILL);
 322         if (rev_list.pid)
 323                 kill(rev_list.pid, SIGKILL);
 324         send_client_data(3, abort_msg, sizeof(abort_msg));
 325         die("git-upload-pack: %s", abort_msg);
 326 }
 327
 328 static int got_sha1(char *hex, unsigned char *sha1)
 329 {
 330         struct object *o;
 331         int we_knew_they_have = 0;
 332
 333         if (get_sha1_hex(hex, sha1))
 334                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 335         if (!has_sha1_file(sha1))
 336                 return -1;
 337
 338         o = lookup_object(sha1);
 339         if (!(o && o->parsed))
 340                 o = parse_object(sha1);
 341         if (!o)
 342                 die("oops (%s)", sha1_to_hex(sha1));
 343         if (o->type == OBJ_COMMIT) {
 344                 struct commit_list *parents;
 345                 struct commit *commit = (struct commit *)o;
 346                 if (o->flags & THEY_HAVE)
 347                         we_knew_they_have = 1;
 348                 else
 349                         o->flags |= THEY_HAVE;
 350                 if (!oldest_have || (commit->date < oldest_have))
 351                         oldest_have = commit->date;
 352                 for (parents = commit->parents;
 353                      parents;
 354                      parents = parents->next)
 355                         parents->item->object.flags |= THEY_HAVE;
 356         }
 357         if (!we_knew_they_have) {
 358                 add_object_array(o, NULL, &have_obj);
 359                 return 1;
 360         }
 361         return 0;
 362 }
 363
 364 static int reachable(struct commit *want)
 365 {
 366         struct commit_list *work = NULL;
 367
 368         insert_by_date(want, &work);
 369         while (work) {
 370                 struct commit_list *list = work->next;
 371                 struct commit *commit = work->item;
 372                 free(work);
 373                 work = list;
 374
 375                 if (commit->object.flags & THEY_HAVE) {
 376                         want->object.flags |= COMMON_KNOWN;
 377                         break;
 378                 }
 379                 if (!commit->object.parsed)
 380                         parse_object(commit->object.sha1);
 381                 if (commit->object.flags & REACHABLE)
 382                         continue;
 383                 commit->object.flags |= REACHABLE;
 384                 if (commit->date < oldest_have)
 385                         continue;
 386                 for (list = commit->parents; list; list = list->next) {
 387                         struct commit *parent = list->item;
 388                         if (!(parent->object.flags & REACHABLE))
 389                                 insert_by_date(parent, &work);
 390                 }
 391         }
 392         want->object.flags |= REACHABLE;
 393         clear_commit_marks(want, REACHABLE);
 394         free_commit_list(work);
 395         return (want->object.flags & COMMON_KNOWN);
 396 }
 397
 398 static int ok_to_give_up(void)
 399 {
 400         int i;
 401
 402         if (!have_obj.nr)
 403                 return 0;
 404
 405         for (i = 0; i < want_obj.nr; i++) {
 406                 struct object *want = want_obj.objects[i].item;
 407
 408                 if (want->flags & COMMON_KNOWN)
 409                         continue;
 410                 want = deref_tag(want, "a want line", 0);
 411                 if (!want || want->type != OBJ_COMMIT) {
 412                         /* no way to tell if this is reachable by
 413                          * looking at the ancestry chain alone, so
 414                          * leave a note to ourselves not to worry about
 415                          * this object anymore.
 416                          */
 417                         want_obj.objects[i].item->flags |= COMMON_KNOWN;
 418                         continue;
 419                 }
 420                 if (!reachable((struct commit *)want))
 421                         return 0;
 422         }
 423         return 1;
 424 }
 425
 426 static int get_common_commits(void)
 427 {
 428         static char line[1000];
 429         unsigned char sha1[20];
 430         char hex[41], last_hex[41];
 431         int len;
 432
 433         track_object_refs = 0;
 434         save_commit_buffer = 0;
 435
 436         for(;;) {
 437                 len = packet_read_line(0, line, sizeof(line));
 438                 reset_timeout();
 439
 440                 if (!len) {
 441                         if (have_obj.nr == 0 || multi_ack)
 442                                 packet_write(1, "NAK\n");
 443                         continue;
 444                 }
 445                 len = strip(line, len);
 446                 if (!prefixcmp(line, "have ")) {
 447                         switch (got_sha1(line+5, sha1)) {
 448                         case -1: /* they have what we do not */
 449                                 if (multi_ack && ok_to_give_up())
 450                                         packet_write(1, "ACK %s continue\n",
 451                                                      sha1_to_hex(sha1));
 452                                 break;
 453                         default:
 454                                 memcpy(hex, sha1_to_hex(sha1), 41);
 455                                 if (multi_ack) {
 456                                         const char *msg = "ACK %s continue\n";
 457                                         packet_write(1, msg, hex);
 458                                         memcpy(last_hex, hex, 41);
 459                                 }
 460                                 else if (have_obj.nr == 1)
 461                                         packet_write(1, "ACK %s\n", hex);
 462                                 break;
 463                         }
 464                         continue;
 465                 }
 466                 if (!strcmp(line, "done")) {
 467                         if (have_obj.nr > 0) {
 468                                 if (multi_ack)
 469                                         packet_write(1, "ACK %s\n", last_hex);
 470                                 return 0;
 471                         }
 472                         packet_write(1, "NAK\n");
 473                         return -1;
 474                 }
 475                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 476         }
 477 }
 478
 479 static void receive_needs(void)
 480 {
 481         struct object_array shallows = {0, 0, NULL};
 482         static char line[1000];
 483         int len, depth = 0;
 484
 485         for (;;) {
 486                 struct object *o;
 487                 unsigned char sha1_buf[20];
 488                 len = packet_read_line(0, line, sizeof(line));
 489                 reset_timeout();
 490                 if (!len)
 491                         break;
 492
 493                 if (!prefixcmp(line, "shallow ")) {
 494                         unsigned char sha1[20];
 495                         struct object *object;
 496                         use_thin_pack = 0;
 497                         if (get_sha1(line + 8, sha1))
 498                                 die("invalid shallow line: %s", line);
 499                         object = parse_object(sha1);
 500                         if (!object)
 501                                 die("did not find object for %s", line);
 502                         object->flags |= CLIENT_SHALLOW;
 503                         add_object_array(object, NULL, &shallows);
 504                         continue;
 505                 }
 506                 if (!prefixcmp(line, "deepen ")) {
 507                         char *end;
 508                         use_thin_pack = 0;
 509                         depth = strtol(line + 7, &end, 0);
 510                         if (end == line + 7 || depth <= 0)
 511                                 die("Invalid deepen: %s", line);
 512                         continue;
 513                 }
 514                 if (prefixcmp(line, "want ") ||
 515                     get_sha1_hex(line+5, sha1_buf))
 516                         die("git-upload-pack: protocol error, "
 517                             "expected to get sha, not '%s'", line);
 518                 if (strstr(line+45, "multi_ack"))
 519                         multi_ack = 1;
 520                 if (strstr(line+45, "thin-pack"))
 521                         use_thin_pack = 1;
 522                 if (strstr(line+45, "ofs-delta"))
 523                         use_ofs_delta = 1;
 524                 if (strstr(line+45, "side-band-64k"))
 525                         use_sideband = LARGE_PACKET_MAX;
 526                 else if (strstr(line+45, "side-band"))
 527                         use_sideband = DEFAULT_PACKET_MAX;
 528                 if (strstr(line+45, "no-progress"))
 529                         no_progress = 1;
 530
 531                 /* We have sent all our refs already, and the other end
 532                  * should have chosen out of them; otherwise they are
 533                  * asking for nonsense.
 534                  *
 535                  * Hmph.  We may later want to allow "want" line that
 536                  * asks for something like "master~10" (symbolic)...
 537                  * would it make sense?  I don't know.
 538                  */
 539                 o = lookup_object(sha1_buf);
 540                 if (!o || !(o->flags & OUR_REF))
 541                         die("git-upload-pack: not our ref %s", line+5);
 542                 if (!(o->flags & WANTED)) {
 543                         o->flags |= WANTED;
 544                         add_object_array(o, NULL, &want_obj);
 545                 }
 546         }
 547         if (depth == 0 && shallows.nr == 0)
 548                 return;
 549         if (depth > 0) {
 550                 struct commit_list *result, *backup;
 551                 int i;
 552                 backup = result = get_shallow_commits(&want_obj, depth,
 553                         SHALLOW, NOT_SHALLOW);
 554                 while (result) {
 555                         struct object *object = &result->item->object;
 556                         if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
 557                                 packet_write(1, "shallow %s",
 558                                                 sha1_to_hex(object->sha1));
 559                                 register_shallow(object->sha1);
 560                         }
 561                         result = result->next;
 562                 }
 563                 free_commit_list(backup);
 564                 for (i = 0; i < shallows.nr; i++) {
 565                         struct object *object = shallows.objects[i].item;
 566                         if (object->flags & NOT_SHALLOW) {
 567                                 struct commit_list *parents;
 568                                 packet_write(1, "unshallow %s",
 569                                         sha1_to_hex(object->sha1));
 570                                 object->flags &= ~CLIENT_SHALLOW;
 571                                 /* make sure the real parents are parsed */
 572                                 unregister_shallow(object->sha1);
 573                                 object->parsed = 0;
 574                                 parse_commit((struct commit *)object);
 575                                 parents = ((struct commit *)object)->parents;
 576                                 while (parents) {
 577                                         add_object_array(&parents->item->object,
 578                                                         NULL, &want_obj);
 579                                         parents = parents->next;
 580                                 }
 581                         }
 582                         /* make sure commit traversal conforms to client */
 583                         register_shallow(object->sha1);
 584                 }
 585                 packet_flush(1);
 586         } else
 587                 if (shallows.nr > 0) {
 588                         int i;
 589                         for (i = 0; i < shallows.nr; i++)
 590                                 register_shallow(shallows.objects[i].item->sha1);
 591                 }
 592         free(shallows.objects);
 593 }
 594
 595 static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 596 {
 597         static const char *capabilities = "multi_ack thin-pack side-band"
 598                 " side-band-64k ofs-delta shallow no-progress";
 599         struct object *o = parse_object(sha1);
 600
 601         if (!o)
 602                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 603
 604         if (capabilities)
 605                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 606                         0, capabilities);
 607         else
 608                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 609         capabilities = NULL;
 610         if (!(o->flags & OUR_REF)) {
 611                 o->flags |= OUR_REF;
 612                 nr_our_refs++;
 613         }
 614         if (o->type == OBJ_TAG) {
 615                 o = deref_tag(o, refname, 0);
 616                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 617         }
 618         return 0;
 619 }
 620
 621 static void upload_pack(void)
 622 {
 623         reset_timeout();
 624         head_ref(send_ref, NULL);
 625         for_each_ref(send_ref, NULL);
 626         packet_flush(1);
 627         receive_needs();
 628         if (want_obj.nr) {
 629                 get_common_commits();
 630                 create_pack_file();
 631         }
 632 }
 633
 634 int main(int argc, char **argv)
 635 {
 636         char *dir;
 637         int i;
 638         int strict = 0;
 639
 640         for (i = 1; i < argc; i++) {
 641                 char *arg = argv[i];
 642
 643                 if (arg[0] != '-')
 644                         break;
 645                 if (!strcmp(arg, "--strict")) {
 646                         strict = 1;
 647                         continue;
 648                 }
 649                 if (!prefixcmp(arg, "--timeout=")) {
 650                         timeout = atoi(arg+10);
 651                         continue;
 652                 }
 653                 if (!strcmp(arg, "--")) {
 654                         i++;
 655                         break;
 656                 }
 657         }
 658
 659         if (i != argc-1)
 660                 usage(upload_pack_usage);
 661         dir = argv[i];
 662
 663         if (!enter_repo(dir, strict))
 664                 die("'%s': unable to chdir or not a git archive", dir);
 665         if (is_repository_shallow())
 666                 die("attempt to fetch/clone from a shallow repository");
 667         upload_pack();
 668         return 0;
 669 }