upload-pack.c

   1 #include <signal.h>
   2 #include <sys/wait.h>
   3 #include <sys/poll.h>
   4 #include "cache.h"
   5 #include "refs.h"
   6 #include "pkt-line.h"
   7 #include "sideband.h"
   8 #include "tag.h"
   9 #include "object.h"
  10 #include "commit.h"
  11 #include "exec_cmd.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "list-objects.h"
  15
  16 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  17
  18 /* bits #0..7 in revision.h, #8..10 in commit.c */
  19 #define THEY_HAVE       (1u << 11)
  20 #define OUR_REF         (1u << 12)
  21 #define WANTED          (1u << 13)
  22 #define COMMON_KNOWN    (1u << 14)
  23 #define REACHABLE       (1u << 15)
  24
  25 static unsigned long oldest_have;
  26
  27 static int multi_ack, nr_our_refs;
  28 static int use_thin_pack, use_ofs_delta;
  29 static struct object_array have_obj;
  30 static struct object_array want_obj;
  31 static unsigned int timeout;
  32 /* 0 for no sideband,
  33  * otherwise maximum packet size (up to 65520 bytes).
  34  */
  35 static int use_sideband;
  36
  37 static void reset_timeout(void)
  38 {
  39         alarm(timeout);
  40 }
  41
  42 static int strip(char *line, int len)
  43 {
  44         if (len && line[len-1] == '\n')
  45                 line[--len] = 0;
  46         return len;
  47 }
  48
  49 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  50 {
  51         if (use_sideband)
  52                 return send_sideband(1, fd, data, sz, use_sideband);
  53         if (fd == 3)
  54                 /* emergency quit */
  55                 fd = 2;
  56         if (fd == 2) {
  57                 xwrite(fd, data, sz);
  58                 return sz;
  59         }
  60         return safe_write(fd, data, sz);
  61 }
  62
  63 FILE *pack_pipe = NULL;
  64 static void show_commit(struct commit *commit)
  65 {
  66         if (commit->object.flags & BOUNDARY)
  67                 fputc('-', pack_pipe);
  68         if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
  69                 die("broken output pipe");
  70         fputc('\n', pack_pipe);
  71         fflush(pack_pipe);
  72         free(commit->buffer);
  73         commit->buffer = NULL;
  74 }
  75
  76 static void show_object(struct object_array_entry *p)
  77 {
  78         /* An object with name "foo\n0000000..." can be used to
  79          * confuse downstream git-pack-objects very badly.
  80          */
  81         const char *ep = strchr(p->name, '\n');
  82         if (ep) {
  83                 fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(p->item->sha1),
  84                        (int) (ep - p->name),
  85                        p->name);
  86         }
  87         else
  88                 fprintf(pack_pipe, "%s %s\n",
  89                                 sha1_to_hex(p->item->sha1), p->name);
  90 }
  91
  92 static void show_edge(struct commit *commit)
  93 {
  94         fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
  95 }
  96
  97 static void create_pack_file(void)
  98 {
  99         /* Pipes between rev-list to pack-objects, pack-objects to us
 100          * and pack-objects error stream for progress bar.
 101          */
 102         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
 103         pid_t pid_rev_list, pid_pack_objects;
 104         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
 105         char data[8193], progress[128];
 106         char abort_msg[] = "aborting due to possible repository "
 107                 "corruption on the remote side.";
 108         int buffered = -1;
 109
 110         if (pipe(lp_pipe) < 0)
 111                 die("git-upload-pack: unable to create pipe");
 112         pid_rev_list = fork();
 113         if (pid_rev_list < 0)
 114                 die("git-upload-pack: unable to fork git-rev-list");
 115
 116         if (!pid_rev_list) {
 117                 int i;
 118                 struct rev_info revs;
 119
 120                 pack_pipe = fdopen(lp_pipe[1], "w");
 121
 122                 if (create_full_pack)
 123                         use_thin_pack = 0; /* no point doing it */
 124                 init_revisions(&revs, NULL);
 125                 revs.tag_objects = 1;
 126                 revs.tree_objects = 1;
 127                 revs.blob_objects = 1;
 128                 if (use_thin_pack)
 129                         revs.edge_hint = 1;
 130
 131                 if (create_full_pack) {
 132                         const char *args[] = {"rev-list", "--all", NULL};
 133                         setup_revisions(2, args, &revs, NULL);
 134                 } else {
 135                         for (i = 0; i < want_obj.nr; i++) {
 136                                 struct object *o = want_obj.objects[i].item;
 137                                 add_pending_object(&revs, o, NULL);
 138                         }
 139                         for (i = 0; i < have_obj.nr; i++) {
 140                                 struct object *o = have_obj.objects[i].item;
 141                                 o->flags |= UNINTERESTING;
 142                                 add_pending_object(&revs, o, NULL);
 143                         }
 144                         setup_revisions(0, NULL, &revs, NULL);
 145                 }
 146                 prepare_revision_walk(&revs);
 147                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
 148                 traverse_commit_list(&revs, show_commit, show_object);
 149                 exit(0);
 150         }
 151
 152         if (pipe(pu_pipe) < 0)
 153                 die("git-upload-pack: unable to create pipe");
 154         if (pipe(pe_pipe) < 0)
 155                 die("git-upload-pack: unable to create pipe");
 156         pid_pack_objects = fork();
 157         if (pid_pack_objects < 0) {
 158                 /* daemon sets things up to ignore TERM */
 159                 kill(pid_rev_list, SIGKILL);
 160                 die("git-upload-pack: unable to fork git-pack-objects");
 161         }
 162         if (!pid_pack_objects) {
 163                 dup2(lp_pipe[0], 0);
 164                 dup2(pu_pipe[1], 1);
 165                 dup2(pe_pipe[1], 2);
 166
 167                 close(lp_pipe[0]);
 168                 close(lp_pipe[1]);
 169                 close(pu_pipe[0]);
 170                 close(pu_pipe[1]);
 171                 close(pe_pipe[0]);
 172                 close(pe_pipe[1]);
 173                 execl_git_cmd("pack-objects", "--stdout", "--progress",
 174                               use_ofs_delta ? "--delta-base-offset" : NULL,
 175                               NULL);
 176                 kill(pid_rev_list, SIGKILL);
 177                 die("git-upload-pack: unable to exec git-pack-objects");
 178         }
 179
 180         close(lp_pipe[0]);
 181         close(lp_pipe[1]);
 182
 183         /* We read from pe_pipe[0] to capture stderr output for
 184          * progress bar, and pu_pipe[0] to capture the pack data.
 185          */
 186         close(pe_pipe[1]);
 187         close(pu_pipe[1]);
 188
 189         while (1) {
 190                 const char *who;
 191                 struct pollfd pfd[2];
 192                 pid_t pid;
 193                 int status;
 194                 ssize_t sz;
 195                 int pe, pu, pollsize;
 196
 197                 reset_timeout();
 198
 199                 pollsize = 0;
 200                 pe = pu = -1;
 201
 202                 if (0 <= pu_pipe[0]) {
 203                         pfd[pollsize].fd = pu_pipe[0];
 204                         pfd[pollsize].events = POLLIN;
 205                         pu = pollsize;
 206                         pollsize++;
 207                 }
 208                 if (0 <= pe_pipe[0]) {
 209                         pfd[pollsize].fd = pe_pipe[0];
 210                         pfd[pollsize].events = POLLIN;
 211                         pe = pollsize;
 212                         pollsize++;
 213                 }
 214
 215                 if (pollsize) {
 216                         if (poll(pfd, pollsize, -1) < 0) {
 217                                 if (errno != EINTR) {
 218                                         error("poll failed, resuming: %s",
 219                                               strerror(errno));
 220                                         sleep(1);
 221                                 }
 222                                 continue;
 223                         }
 224                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 225                                 /* Data ready; we keep the last byte
 226                                  * to ourselves in case we detect
 227                                  * broken rev-list, so that we can
 228                                  * leave the stream corrupted.  This
 229                                  * is unfortunate -- unpack-objects
 230                                  * would happily accept a valid pack
 231                                  * data with trailing garbage, so
 232                                  * appending garbage after we pass all
 233                                  * the pack data is not good enough to
 234                                  * signal breakage to downstream.
 235                                  */
 236                                 char *cp = data;
 237                                 ssize_t outsz = 0;
 238                                 if (0 <= buffered) {
 239                                         *cp++ = buffered;
 240                                         outsz++;
 241                                 }
 242                                 sz = read(pu_pipe[0], cp,
 243                                           sizeof(data) - outsz);
 244                                 if (0 < sz)
 245                                                 ;
 246                                 else if (sz == 0) {
 247                                         close(pu_pipe[0]);
 248                                         pu_pipe[0] = -1;
 249                                 }
 250                                 else
 251                                         goto fail;
 252                                 sz += outsz;
 253                                 if (1 < sz) {
 254                                         buffered = data[sz-1] & 0xFF;
 255                                         sz--;
 256                                 }
 257                                 else
 258                                         buffered = -1;
 259                                 sz = send_client_data(1, data, sz);
 260                                 if (sz < 0)
 261                                         goto fail;
 262                         }
 263                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 264                                 /* Status ready; we ship that in the side-band
 265                                  * or dump to the standard error.
 266                                  */
 267                                 sz = read(pe_pipe[0], progress,
 268                                           sizeof(progress));
 269                                 if (0 < sz)
 270                                         send_client_data(2, progress, sz);
 271                                 else if (sz == 0) {
 272                                         close(pe_pipe[0]);
 273                                         pe_pipe[0] = -1;
 274                                 }
 275                                 else
 276                                         goto fail;
 277                         }
 278                 }
 279
 280                 /* See if the children are still there */
 281                 if (pid_rev_list || pid_pack_objects) {
 282                         pid = waitpid(-1, &status, WNOHANG);
 283                         if (!pid)
 284                                 continue;
 285                         who = ((pid == pid_rev_list) ? "git-rev-list" :
 286                                (pid == pid_pack_objects) ? "git-pack-objects" :
 287                                NULL);
 288                         if (!who) {
 289                                 if (pid < 0) {
 290                                         error("git-upload-pack: %s",
 291                                               strerror(errno));
 292                                         goto fail;
 293                                 }
 294                                 error("git-upload-pack: we weren't "
 295                                       "waiting for %d", pid);
 296                                 continue;
 297                         }
 298                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 299                                 error("git-upload-pack: %s died with error.",
 300                                       who);
 301                                 goto fail;
 302                         }
 303                         if (pid == pid_rev_list)
 304                                 pid_rev_list = 0;
 305                         if (pid == pid_pack_objects)
 306                                 pid_pack_objects = 0;
 307                         if (pid_rev_list || pid_pack_objects)
 308                                 continue;
 309                 }
 310
 311                 /* both died happily */
 312                 if (pollsize)
 313                         continue;
 314
 315                 /* flush the data */
 316                 if (0 <= buffered) {
 317                         data[0] = buffered;
 318                         sz = send_client_data(1, data, 1);
 319                         if (sz < 0)
 320                                 goto fail;
 321                         fprintf(stderr, "flushed.\n");
 322                 }
 323                 if (use_sideband)
 324                         packet_flush(1);
 325                 return;
 326         }
 327  fail:
 328         if (pid_pack_objects)
 329                 kill(pid_pack_objects, SIGKILL);
 330         if (pid_rev_list)
 331                 kill(pid_rev_list, SIGKILL);
 332         send_client_data(3, abort_msg, sizeof(abort_msg));
 333         die("git-upload-pack: %s", abort_msg);
 334 }
 335
 336 static int got_sha1(char *hex, unsigned char *sha1)
 337 {
 338         struct object *o;
 339         int we_knew_they_have = 0;
 340
 341         if (get_sha1_hex(hex, sha1))
 342                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 343         if (!has_sha1_file(sha1))
 344                 return -1;
 345
 346         o = lookup_object(sha1);
 347         if (!(o && o->parsed))
 348                 o = parse_object(sha1);
 349         if (!o)
 350                 die("oops (%s)", sha1_to_hex(sha1));
 351         if (o->type == OBJ_COMMIT) {
 352                 struct commit_list *parents;
 353                 struct commit *commit = (struct commit *)o;
 354                 if (o->flags & THEY_HAVE)
 355                         we_knew_they_have = 1;
 356                 else
 357                         o->flags |= THEY_HAVE;
 358                 if (!oldest_have || (commit->date < oldest_have))
 359                         oldest_have = commit->date;
 360                 for (parents = commit->parents;
 361                      parents;
 362                      parents = parents->next)
 363                         parents->item->object.flags |= THEY_HAVE;
 364         }
 365         if (!we_knew_they_have) {
 366                 add_object_array(o, NULL, &have_obj);
 367                 return 1;
 368         }
 369         return 0;
 370 }
 371
 372 static int reachable(struct commit *want)
 373 {
 374         struct commit_list *work = NULL;
 375
 376         insert_by_date(want, &work);
 377         while (work) {
 378                 struct commit_list *list = work->next;
 379                 struct commit *commit = work->item;
 380                 free(work);
 381                 work = list;
 382
 383                 if (commit->object.flags & THEY_HAVE) {
 384                         want->object.flags |= COMMON_KNOWN;
 385                         break;
 386                 }
 387                 if (!commit->object.parsed)
 388                         parse_object(commit->object.sha1);
 389                 if (commit->object.flags & REACHABLE)
 390                         continue;
 391                 commit->object.flags |= REACHABLE;
 392                 if (commit->date < oldest_have)
 393                         continue;
 394                 for (list = commit->parents; list; list = list->next) {
 395                         struct commit *parent = list->item;
 396                         if (!(parent->object.flags & REACHABLE))
 397                                 insert_by_date(parent, &work);
 398                 }
 399         }
 400         want->object.flags |= REACHABLE;
 401         clear_commit_marks(want, REACHABLE);
 402         free_commit_list(work);
 403         return (want->object.flags & COMMON_KNOWN);
 404 }
 405
 406 static int ok_to_give_up(void)
 407 {
 408         int i;
 409
 410         if (!have_obj.nr)
 411                 return 0;
 412
 413         for (i = 0; i < want_obj.nr; i++) {
 414                 struct object *want = want_obj.objects[i].item;
 415
 416                 if (want->flags & COMMON_KNOWN)
 417                         continue;
 418                 want = deref_tag(want, "a want line", 0);
 419                 if (!want || want->type != OBJ_COMMIT) {
 420                         /* no way to tell if this is reachable by
 421                          * looking at the ancestry chain alone, so
 422                          * leave a note to ourselves not to worry about
 423                          * this object anymore.
 424                          */
 425                         want_obj.objects[i].item->flags |= COMMON_KNOWN;
 426                         continue;
 427                 }
 428                 if (!reachable((struct commit *)want))
 429                         return 0;
 430         }
 431         return 1;
 432 }
 433
 434 static int get_common_commits(void)
 435 {
 436         static char line[1000];
 437         unsigned char sha1[20];
 438         char hex[41], last_hex[41];
 439         int len;
 440
 441         track_object_refs = 0;
 442         save_commit_buffer = 0;
 443
 444         for(;;) {
 445                 len = packet_read_line(0, line, sizeof(line));
 446                 reset_timeout();
 447
 448                 if (!len) {
 449                         if (have_obj.nr == 0 || multi_ack)
 450                                 packet_write(1, "NAK\n");
 451                         continue;
 452                 }
 453                 len = strip(line, len);
 454                 if (!strncmp(line, "have ", 5)) {
 455                         switch (got_sha1(line+5, sha1)) {
 456                         case -1: /* they have what we do not */
 457                                 if (multi_ack && ok_to_give_up())
 458                                         packet_write(1, "ACK %s continue\n",
 459                                                      sha1_to_hex(sha1));
 460                                 break;
 461                         default:
 462                                 memcpy(hex, sha1_to_hex(sha1), 41);
 463                                 if (multi_ack) {
 464                                         const char *msg = "ACK %s continue\n";
 465                                         packet_write(1, msg, hex);
 466                                         memcpy(last_hex, hex, 41);
 467                                 }
 468                                 else if (have_obj.nr == 1)
 469                                         packet_write(1, "ACK %s\n", hex);
 470                                 break;
 471                         }
 472                         continue;
 473                 }
 474                 if (!strcmp(line, "done")) {
 475                         if (have_obj.nr > 0) {
 476                                 if (multi_ack)
 477                                         packet_write(1, "ACK %s\n", last_hex);
 478                                 return 0;
 479                         }
 480                         packet_write(1, "NAK\n");
 481                         return -1;
 482                 }
 483                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 484         }
 485 }
 486
 487 static void receive_needs(void)
 488 {
 489         struct object_array shallows = {0, 0, NULL};
 490         static char line[1000];
 491         int len;
 492
 493         for (;;) {
 494                 struct object *o;
 495                 unsigned char sha1_buf[20];
 496                 len = packet_read_line(0, line, sizeof(line));
 497                 reset_timeout();
 498                 if (!len)
 499                         break;
 500
 501                 if (!strncmp("shallow ", line, 8)) {
 502                         unsigned char sha1[20];
 503                         struct object *object;
 504                         if (get_sha1(line + 8, sha1))
 505                                 die("invalid shallow line: %s", line);
 506                         object = parse_object(sha1);
 507                         if (!object)
 508                                 die("did not find object for %s", line);
 509                         add_object_array(object, NULL, &shallows);
 510                         continue;
 511                 }
 512                 if (strncmp("want ", line, 5) ||
 513                     get_sha1_hex(line+5, sha1_buf))
 514                         die("git-upload-pack: protocol error, "
 515                             "expected to get sha, not '%s'", line);
 516                 if (strstr(line+45, "multi_ack"))
 517                         multi_ack = 1;
 518                 if (strstr(line+45, "thin-pack"))
 519                         use_thin_pack = 1;
 520                 if (strstr(line+45, "ofs-delta"))
 521                         use_ofs_delta = 1;
 522                 if (strstr(line+45, "side-band-64k"))
 523                         use_sideband = LARGE_PACKET_MAX;
 524                 else if (strstr(line+45, "side-band"))
 525                         use_sideband = DEFAULT_PACKET_MAX;
 526
 527                 /* We have sent all our refs already, and the other end
 528                  * should have chosen out of them; otherwise they are
 529                  * asking for nonsense.
 530                  *
 531                  * Hmph.  We may later want to allow "want" line that
 532                  * asks for something like "master~10" (symbolic)...
 533                  * would it make sense?  I don't know.
 534                  */
 535                 o = lookup_object(sha1_buf);
 536                 if (!o || !(o->flags & OUR_REF))
 537                         die("git-upload-pack: not our ref %s", line+5);
 538                 if (!(o->flags & WANTED)) {
 539                         o->flags |= WANTED;
 540                         add_object_array(o, NULL, &want_obj);
 541                 }
 542         }
 543         if (shallows.nr > 0) {
 544                 int i;
 545                 for (i = 0; i < shallows.nr; i++)
 546                         register_shallow(shallows.objects[i].item->sha1);
 547         }
 548 }
 549
 550 static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 551 {
 552         static const char *capabilities = "multi_ack thin-pack side-band"
 553                 " side-band-64k ofs-delta shallow";
 554         struct object *o = parse_object(sha1);
 555
 556         if (!o)
 557                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 558
 559         if (capabilities)
 560                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 561                         0, capabilities);
 562         else
 563                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 564         capabilities = NULL;
 565         if (!(o->flags & OUR_REF)) {
 566                 o->flags |= OUR_REF;
 567                 nr_our_refs++;
 568         }
 569         if (o->type == OBJ_TAG) {
 570                 o = deref_tag(o, refname, 0);
 571                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 572         }
 573         return 0;
 574 }
 575
 576 static void upload_pack(void)
 577 {
 578         reset_timeout();
 579         head_ref(send_ref, NULL);
 580         for_each_ref(send_ref, NULL);
 581         packet_flush(1);
 582         receive_needs();
 583         if (want_obj.nr) {
 584                 get_common_commits();
 585                 create_pack_file();
 586         }
 587 }
 588
 589 int main(int argc, char **argv)
 590 {
 591         char *dir;
 592         int i;
 593         int strict = 0;
 594
 595         for (i = 1; i < argc; i++) {
 596                 char *arg = argv[i];
 597
 598                 if (arg[0] != '-')
 599                         break;
 600                 if (!strcmp(arg, "--strict")) {
 601                         strict = 1;
 602                         continue;
 603                 }
 604                 if (!strncmp(arg, "--timeout=", 10)) {
 605                         timeout = atoi(arg+10);
 606                         continue;
 607                 }
 608                 if (!strcmp(arg, "--")) {
 609                         i++;
 610                         break;
 611                 }
 612         }
 613
 614         if (i != argc-1)
 615                 usage(upload_pack_usage);
 616         dir = argv[i];
 617
 618         if (!enter_repo(dir, strict))
 619                 die("'%s': unable to chdir or not a git archive", dir);
 620
 621         upload_pack();
 622         return 0;
 623 }