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