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