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, use_include_tag;
  31 static int no_progress;
  32 static struct object_array have_obj;
  33 static struct object_array want_obj;
  34 static unsigned int timeout;
  35 /* 0 for no sideband,
  36  * otherwise maximum packet size (up to 65520 bytes).
  37  */
  38 static int use_sideband;
  39 static int debug_fd;
  40
  41 static void reset_timeout(void)
  42 {
  43         alarm(timeout);
  44 }
  45
  46 static int strip(char *line, int len)
  47 {
  48         if (len && line[len-1] == '\n')
  49                 line[--len] = 0;
  50         return len;
  51 }
  52
  53 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  54 {
  55         if (use_sideband)
  56                 return send_sideband(1, fd, data, sz, use_sideband);
  57         if (fd == 3)
  58                 /* emergency quit */
  59                 fd = 2;
  60         if (fd == 2) {
  61                 /* XXX: are we happy to lose stuff here? */
  62                 xwrite(fd, data, sz);
  63                 return sz;
  64         }
  65         return safe_write(fd, data, sz);
  66 }
  67
  68 static FILE *pack_pipe = NULL;
  69 static void show_commit(struct commit *commit)
  70 {
  71         if (commit->object.flags & BOUNDARY)
  72                 fputc('-', pack_pipe);
  73         if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
  74                 die("broken output pipe");
  75         fputc('\n', pack_pipe);
  76         fflush(pack_pipe);
  77         free(commit->buffer);
  78         commit->buffer = NULL;
  79 }
  80
  81 static void show_object(struct object_array_entry *p)
  82 {
  83         /* An object with name "foo\n0000000..." can be used to
  84          * confuse downstream git-pack-objects very badly.
  85          */
  86         const char *ep = strchr(p->name, '\n');
  87         if (ep) {
  88                 fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(p->item->sha1),
  89                        (int) (ep - p->name),
  90                        p->name);
  91         }
  92         else
  93                 fprintf(pack_pipe, "%s %s\n",
  94                                 sha1_to_hex(p->item->sha1), p->name);
  95 }
  96
  97 static void show_edge(struct commit *commit)
  98 {
  99         fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
 100 }
 101
 102 static int do_rev_list(int fd, void *create_full_pack)
 103 {
 104         int i;
 105         struct rev_info revs;
 106
 107         pack_pipe = fdopen(fd, "w");
 108         if (create_full_pack)
 109                 use_thin_pack = 0; /* no point doing it */
 110         init_revisions(&revs, NULL);
 111         revs.tag_objects = 1;
 112         revs.tree_objects = 1;
 113         revs.blob_objects = 1;
 114         if (use_thin_pack)
 115                 revs.edge_hint = 1;
 116
 117         if (create_full_pack) {
 118                 const char *args[] = {"rev-list", "--all", NULL};
 119                 setup_revisions(2, args, &revs, NULL);
 120         } else {
 121                 for (i = 0; i < want_obj.nr; i++) {
 122                         struct object *o = want_obj.objects[i].item;
 123                         /* why??? */
 124                         o->flags &= ~UNINTERESTING;
 125                         add_pending_object(&revs, o, NULL);
 126                 }
 127                 for (i = 0; i < have_obj.nr; i++) {
 128                         struct object *o = have_obj.objects[i].item;
 129                         o->flags |= UNINTERESTING;
 130                         add_pending_object(&revs, o, NULL);
 131                 }
 132                 setup_revisions(0, NULL, &revs, NULL);
 133         }
 134         if (prepare_revision_walk(&revs))
 135                 die("revision walk setup failed");
 136         mark_edges_uninteresting(revs.commits, &revs, show_edge);
 137         traverse_commit_list(&revs, show_commit, show_object);
 138         return 0;
 139 }
 140
 141 static void create_pack_file(void)
 142 {
 143         struct async rev_list;
 144         struct child_process pack_objects;
 145         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
 146         char data[8193], progress[128];
 147         char abort_msg[] = "aborting due to possible repository "
 148                 "corruption on the remote side.";
 149         int buffered = -1;
 150         ssize_t sz;
 151         const char *argv[10];
 152         int arg = 0;
 153
 154         rev_list.proc = do_rev_list;
 155         /* .data is just a boolean: any non-NULL value will do */
 156         rev_list.data = create_full_pack ? &rev_list : NULL;
 157         if (start_async(&rev_list))
 158                 die("git-upload-pack: unable to fork git-rev-list");
 159
 160         argv[arg++] = "pack-objects";
 161         argv[arg++] = "--stdout";
 162         if (!no_progress)
 163                 argv[arg++] = "--progress";
 164         if (use_ofs_delta)
 165                 argv[arg++] = "--delta-base-offset";
 166         if (use_include_tag)
 167                 argv[arg++] = "--include-tag";
 168         argv[arg++] = NULL;
 169
 170         memset(&pack_objects, 0, sizeof(pack_objects));
 171         pack_objects.in = rev_list.out; /* start_command closes it */
 172         pack_objects.out = -1;
 173         pack_objects.err = -1;
 174         pack_objects.git_cmd = 1;
 175         pack_objects.argv = argv;
 176
 177         if (start_command(&pack_objects))
 178                 die("git-upload-pack: unable to fork git-pack-objects");
 179
 180         /* We read from pack_objects.err to capture stderr output for
 181          * progress bar, and pack_objects.out to capture the pack data.
 182          */
 183
 184         while (1) {
 185                 struct pollfd pfd[2];
 186                 int pe, pu, pollsize;
 187
 188                 reset_timeout();
 189
 190                 pollsize = 0;
 191                 pe = pu = -1;
 192
 193                 if (0 <= pack_objects.out) {
 194                         pfd[pollsize].fd = pack_objects.out;
 195                         pfd[pollsize].events = POLLIN;
 196                         pu = pollsize;
 197                         pollsize++;
 198                 }
 199                 if (0 <= pack_objects.err) {
 200                         pfd[pollsize].fd = pack_objects.err;
 201                         pfd[pollsize].events = POLLIN;
 202                         pe = pollsize;
 203                         pollsize++;
 204                 }
 205
 206                 if (!pollsize)
 207                         break;
 208
 209                 if (poll(pfd, pollsize, -1) < 0) {
 210                         if (errno != EINTR) {
 211                                 error("poll failed, resuming: %s",
 212                                       strerror(errno));
 213                                 sleep(1);
 214                         }
 215                         continue;
 216                 }
 217                 if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 218                         /* Data ready; we keep the last byte to ourselves
 219                          * in case we detect broken rev-list, so that we
 220                          * can leave the stream corrupted.  This is
 221                          * unfortunate -- unpack-objects would happily
 222                          * accept a valid packdata with trailing garbage,
 223                          * so appending garbage after we pass all the
 224                          * pack data is not good enough to signal
 225                          * breakage to downstream.
 226                          */
 227                         char *cp = data;
 228                         ssize_t outsz = 0;
 229                         if (0 <= buffered) {
 230                                 *cp++ = buffered;
 231                                 outsz++;
 232                         }
 233                         sz = xread(pack_objects.out, cp,
 234                                   sizeof(data) - outsz);
 235                         if (0 < sz)
 236                                         ;
 237                         else if (sz == 0) {
 238                                 close(pack_objects.out);
 239                                 pack_objects.out = -1;
 240                         }
 241                         else
 242                                 goto fail;
 243                         sz += outsz;
 244                         if (1 < sz) {
 245                                 buffered = data[sz-1] & 0xFF;
 246                                 sz--;
 247                         }
 248                         else
 249                                 buffered = -1;
 250                         sz = send_client_data(1, data, sz);
 251                         if (sz < 0)
 252                                 goto fail;
 253                 }
 254                 if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 255                         /* Status ready; we ship that in the side-band
 256                          * or dump to the standard error.
 257                          */
 258                         sz = xread(pack_objects.err, progress,
 259                                   sizeof(progress));
 260                         if (0 < sz)
 261                                 send_client_data(2, progress, sz);
 262                         else if (sz == 0) {
 263                                 close(pack_objects.err);
 264                                 pack_objects.err = -1;
 265                         }
 266                         else
 267                                 goto fail;
 268                 }
 269         }
 270
 271         if (finish_command(&pack_objects)) {
 272                 error("git-upload-pack: git-pack-objects died with error.");
 273                 goto fail;
 274         }
 275         if (finish_async(&rev_list))
 276                 goto fail;      /* error was already reported */
 277
 278         /* flush the data */
 279         if (0 <= buffered) {
 280                 data[0] = buffered;
 281                 sz = send_client_data(1, data, 1);
 282                 if (sz < 0)
 283                         goto fail;
 284                 fprintf(stderr, "flushed.\n");
 285         }
 286         if (use_sideband)
 287                 packet_flush(1);
 288         return;
 289
 290  fail:
 291         send_client_data(3, abort_msg, sizeof(abort_msg));
 292         die("git-upload-pack: %s", abort_msg);
 293 }
 294
 295 static int got_sha1(char *hex, unsigned char *sha1)
 296 {
 297         struct object *o;
 298         int we_knew_they_have = 0;
 299
 300         if (get_sha1_hex(hex, sha1))
 301                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 302         if (!has_sha1_file(sha1))
 303                 return -1;
 304
 305         o = lookup_object(sha1);
 306         if (!(o && o->parsed))
 307                 o = parse_object(sha1);
 308         if (!o)
 309                 die("oops (%s)", sha1_to_hex(sha1));
 310         if (o->type == OBJ_COMMIT) {
 311                 struct commit_list *parents;
 312                 struct commit *commit = (struct commit *)o;
 313                 if (o->flags & THEY_HAVE)
 314                         we_knew_they_have = 1;
 315                 else
 316                         o->flags |= THEY_HAVE;
 317                 if (!oldest_have || (commit->date < oldest_have))
 318                         oldest_have = commit->date;
 319                 for (parents = commit->parents;
 320                      parents;
 321                      parents = parents->next)
 322                         parents->item->object.flags |= THEY_HAVE;
 323         }
 324         if (!we_knew_they_have) {
 325                 add_object_array(o, NULL, &have_obj);
 326                 return 1;
 327         }
 328         return 0;
 329 }
 330
 331 static int reachable(struct commit *want)
 332 {
 333         struct commit_list *work = NULL;
 334
 335         insert_by_date(want, &work);
 336         while (work) {
 337                 struct commit_list *list = work->next;
 338                 struct commit *commit = work->item;
 339                 free(work);
 340                 work = list;
 341
 342                 if (commit->object.flags & THEY_HAVE) {
 343                         want->object.flags |= COMMON_KNOWN;
 344                         break;
 345                 }
 346                 if (!commit->object.parsed)
 347                         parse_object(commit->object.sha1);
 348                 if (commit->object.flags & REACHABLE)
 349                         continue;
 350                 commit->object.flags |= REACHABLE;
 351                 if (commit->date < oldest_have)
 352                         continue;
 353                 for (list = commit->parents; list; list = list->next) {
 354                         struct commit *parent = list->item;
 355                         if (!(parent->object.flags & REACHABLE))
 356                                 insert_by_date(parent, &work);
 357                 }
 358         }
 359         want->object.flags |= REACHABLE;
 360         clear_commit_marks(want, REACHABLE);
 361         free_commit_list(work);
 362         return (want->object.flags & COMMON_KNOWN);
 363 }
 364
 365 static int ok_to_give_up(void)
 366 {
 367         int i;
 368
 369         if (!have_obj.nr)
 370                 return 0;
 371
 372         for (i = 0; i < want_obj.nr; i++) {
 373                 struct object *want = want_obj.objects[i].item;
 374
 375                 if (want->flags & COMMON_KNOWN)
 376                         continue;
 377                 want = deref_tag(want, "a want line", 0);
 378                 if (!want || want->type != OBJ_COMMIT) {
 379                         /* no way to tell if this is reachable by
 380                          * looking at the ancestry chain alone, so
 381                          * leave a note to ourselves not to worry about
 382                          * this object anymore.
 383                          */
 384                         want_obj.objects[i].item->flags |= COMMON_KNOWN;
 385                         continue;
 386                 }
 387                 if (!reachable((struct commit *)want))
 388                         return 0;
 389         }
 390         return 1;
 391 }
 392
 393 static int get_common_commits(void)
 394 {
 395         static char line[1000];
 396         unsigned char sha1[20];
 397         char hex[41], last_hex[41];
 398         int len;
 399
 400         save_commit_buffer = 0;
 401
 402         for(;;) {
 403                 len = packet_read_line(0, line, sizeof(line));
 404                 reset_timeout();
 405
 406                 if (!len) {
 407                         if (have_obj.nr == 0 || multi_ack)
 408                                 packet_write(1, "NAK\n");
 409                         continue;
 410                 }
 411                 len = strip(line, len);
 412                 if (!prefixcmp(line, "have ")) {
 413                         switch (got_sha1(line+5, sha1)) {
 414                         case -1: /* they have what we do not */
 415                                 if (multi_ack && ok_to_give_up())
 416                                         packet_write(1, "ACK %s continue\n",
 417                                                      sha1_to_hex(sha1));
 418                                 break;
 419                         default:
 420                                 memcpy(hex, sha1_to_hex(sha1), 41);
 421                                 if (multi_ack) {
 422                                         const char *msg = "ACK %s continue\n";
 423                                         packet_write(1, msg, hex);
 424                                         memcpy(last_hex, hex, 41);
 425                                 }
 426                                 else if (have_obj.nr == 1)
 427                                         packet_write(1, "ACK %s\n", hex);
 428                                 break;
 429                         }
 430                         continue;
 431                 }
 432                 if (!strcmp(line, "done")) {
 433                         if (have_obj.nr > 0) {
 434                                 if (multi_ack)
 435                                         packet_write(1, "ACK %s\n", last_hex);
 436                                 return 0;
 437                         }
 438                         packet_write(1, "NAK\n");
 439                         return -1;
 440                 }
 441                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 442         }
 443 }
 444
 445 static void receive_needs(void)
 446 {
 447         struct object_array shallows = {0, 0, NULL};
 448         static char line[1000];
 449         int len, depth = 0;
 450
 451         if (debug_fd)
 452                 write_in_full(debug_fd, "#S\n", 3);
 453         for (;;) {
 454                 struct object *o;
 455                 unsigned char sha1_buf[20];
 456                 len = packet_read_line(0, line, sizeof(line));
 457                 reset_timeout();
 458                 if (!len)
 459                         break;
 460                 if (debug_fd)
 461                         write_in_full(debug_fd, line, len);
 462
 463                 if (!prefixcmp(line, "shallow ")) {
 464                         unsigned char sha1[20];
 465                         struct object *object;
 466                         use_thin_pack = 0;
 467                         if (get_sha1(line + 8, sha1))
 468                                 die("invalid shallow line: %s", line);
 469                         object = parse_object(sha1);
 470                         if (!object)
 471                                 die("did not find object for %s", line);
 472                         object->flags |= CLIENT_SHALLOW;
 473                         add_object_array(object, NULL, &shallows);
 474                         continue;
 475                 }
 476                 if (!prefixcmp(line, "deepen ")) {
 477                         char *end;
 478                         use_thin_pack = 0;
 479                         depth = strtol(line + 7, &end, 0);
 480                         if (end == line + 7 || depth <= 0)
 481                                 die("Invalid deepen: %s", line);
 482                         continue;
 483                 }
 484                 if (prefixcmp(line, "want ") ||
 485                     get_sha1_hex(line+5, sha1_buf))
 486                         die("git-upload-pack: protocol error, "
 487                             "expected to get sha, not '%s'", line);
 488                 if (strstr(line+45, "multi_ack"))
 489                         multi_ack = 1;
 490                 if (strstr(line+45, "thin-pack"))
 491                         use_thin_pack = 1;
 492                 if (strstr(line+45, "ofs-delta"))
 493                         use_ofs_delta = 1;
 494                 if (strstr(line+45, "side-band-64k"))
 495                         use_sideband = LARGE_PACKET_MAX;
 496                 else if (strstr(line+45, "side-band"))
 497                         use_sideband = DEFAULT_PACKET_MAX;
 498                 if (strstr(line+45, "no-progress"))
 499                         no_progress = 1;
 500                 if (strstr(line+45, "include-tag"))
 501                         use_include_tag = 1;
 502
 503                 /* We have sent all our refs already, and the other end
 504                  * should have chosen out of them; otherwise they are
 505                  * asking for nonsense.
 506                  *
 507                  * Hmph.  We may later want to allow "want" line that
 508                  * asks for something like "master~10" (symbolic)...
 509                  * would it make sense?  I don't know.
 510                  */
 511                 o = lookup_object(sha1_buf);
 512                 if (!o || !(o->flags & OUR_REF))
 513                         die("git-upload-pack: not our ref %s", line+5);
 514                 if (!(o->flags & WANTED)) {
 515                         o->flags |= WANTED;
 516                         add_object_array(o, NULL, &want_obj);
 517                 }
 518         }
 519         if (debug_fd)
 520                 write_in_full(debug_fd, "#E\n", 3);
 521         if (depth == 0 && shallows.nr == 0)
 522                 return;
 523         if (depth > 0) {
 524                 struct commit_list *result, *backup;
 525                 int i;
 526                 backup = result = get_shallow_commits(&want_obj, depth,
 527                         SHALLOW, NOT_SHALLOW);
 528                 while (result) {
 529                         struct object *object = &result->item->object;
 530                         if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
 531                                 packet_write(1, "shallow %s",
 532                                                 sha1_to_hex(object->sha1));
 533                                 register_shallow(object->sha1);
 534                         }
 535                         result = result->next;
 536                 }
 537                 free_commit_list(backup);
 538                 for (i = 0; i < shallows.nr; i++) {
 539                         struct object *object = shallows.objects[i].item;
 540                         if (object->flags & NOT_SHALLOW) {
 541                                 struct commit_list *parents;
 542                                 packet_write(1, "unshallow %s",
 543                                         sha1_to_hex(object->sha1));
 544                                 object->flags &= ~CLIENT_SHALLOW;
 545                                 /* make sure the real parents are parsed */
 546                                 unregister_shallow(object->sha1);
 547                                 object->parsed = 0;
 548                                 if (parse_commit((struct commit *)object))
 549                                         die("invalid commit");
 550                                 parents = ((struct commit *)object)->parents;
 551                                 while (parents) {
 552                                         add_object_array(&parents->item->object,
 553                                                         NULL, &want_obj);
 554                                         parents = parents->next;
 555                                 }
 556                         }
 557                         /* make sure commit traversal conforms to client */
 558                         register_shallow(object->sha1);
 559                 }
 560                 packet_flush(1);
 561         } else
 562                 if (shallows.nr > 0) {
 563                         int i;
 564                         for (i = 0; i < shallows.nr; i++)
 565                                 register_shallow(shallows.objects[i].item->sha1);
 566                 }
 567         free(shallows.objects);
 568 }
 569
 570 static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 571 {
 572         static const char *capabilities = "multi_ack thin-pack side-band"
 573                 " side-band-64k ofs-delta shallow no-progress"
 574                 " include-tag";
 575         struct object *o = parse_object(sha1);
 576
 577         if (!o)
 578                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 579
 580         if (capabilities)
 581                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 582                         0, capabilities);
 583         else
 584                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 585         capabilities = NULL;
 586         if (!(o->flags & OUR_REF)) {
 587                 o->flags |= OUR_REF;
 588                 nr_our_refs++;
 589         }
 590         if (o->type == OBJ_TAG) {
 591                 o = deref_tag(o, refname, 0);
 592                 if (o)
 593                         packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 594         }
 595         return 0;
 596 }
 597
 598 static void upload_pack(void)
 599 {
 600         reset_timeout();
 601         head_ref(send_ref, NULL);
 602         for_each_ref(send_ref, NULL);
 603         packet_flush(1);
 604         receive_needs();
 605         if (want_obj.nr) {
 606                 get_common_commits();
 607                 create_pack_file();
 608         }
 609 }
 610
 611 int main(int argc, char **argv)
 612 {
 613         char *dir;
 614         int i;
 615         int strict = 0;
 616
 617         for (i = 1; i < argc; i++) {
 618                 char *arg = argv[i];
 619
 620                 if (arg[0] != '-')
 621                         break;
 622                 if (!strcmp(arg, "--strict")) {
 623                         strict = 1;
 624                         continue;
 625                 }
 626                 if (!prefixcmp(arg, "--timeout=")) {
 627                         timeout = atoi(arg+10);
 628                         continue;
 629                 }
 630                 if (!strcmp(arg, "--")) {
 631                         i++;
 632                         break;
 633                 }
 634         }
 635
 636         if (i != argc-1)
 637                 usage(upload_pack_usage);
 638
 639         setup_path(NULL);
 640
 641         dir = argv[i];
 642
 643         if (!enter_repo(dir, strict))
 644                 die("'%s': unable to chdir or not a git archive", dir);
 645         if (is_repository_shallow())
 646                 die("attempt to fetch/clone from a shallow repository");
 647         if (getenv("GIT_DEBUG_SEND_PACK"))
 648                 debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));
 649         upload_pack();
 650         return 0;
 651 }