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 "tag.h"
   8 #include "object.h"
   9 #include "commit.h"
  10 #include "exec_cmd.h"
  11
  12 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  13
  14 /* bits #0..7 in revision.h, #8..10 in commit.c */
  15 #define THEY_HAVE       (1u << 11)
  16 #define OUR_REF         (1u << 12)
  17 #define WANTED          (1u << 13)
  18 #define COMMON_KNOWN    (1u << 14)
  19 #define REACHABLE       (1u << 15)
  20
  21 static unsigned long oldest_have = 0;
  22
  23 static int multi_ack = 0, nr_our_refs = 0;
  24 static int use_thin_pack = 0;
  25 static struct object_array have_obj;
  26 static struct object_array want_obj;
  27 static unsigned int timeout = 0;
  28 static int use_sideband = 0;
  29
  30 static void reset_timeout(void)
  31 {
  32         alarm(timeout);
  33 }
  34
  35 static int strip(char *line, int len)
  36 {
  37         if (len && line[len-1] == '\n')
  38                 line[--len] = 0;
  39         return len;
  40 }
  41
  42 #define PACKET_MAX 1000
  43 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  44 {
  45         ssize_t ssz;
  46         const char *p;
  47
  48         if (!data) {
  49                 if (!use_sideband)
  50                         return 0;
  51                 packet_flush(1);
  52         }
  53
  54         if (!use_sideband) {
  55                 if (fd == 3)
  56                         /* emergency quit */
  57                         fd = 2;
  58                 if (fd == 2) {
  59                         xwrite(fd, data, sz);
  60                         return sz;
  61                 }
  62                 return safe_write(fd, data, sz);
  63         }
  64         p = data;
  65         ssz = sz;
  66         while (sz) {
  67                 unsigned n;
  68                 char hdr[5];
  69
  70                 n = sz;
  71                 if (PACKET_MAX - 5 < n)
  72                         n = PACKET_MAX - 5;
  73                 sprintf(hdr, "%04x", n + 5);
  74                 hdr[4] = fd;
  75                 safe_write(1, hdr, 5);
  76                 safe_write(1, p, n);
  77                 p += n;
  78                 sz -= n;
  79         }
  80         return ssz;
  81 }
  82
  83 static void create_pack_file(void)
  84 {
  85         /* Pipes between rev-list to pack-objects, pack-objects to us
  86          * and pack-objects error stream for progress bar.
  87          */
  88         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
  89         pid_t pid_rev_list, pid_pack_objects;
  90         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
  91         char data[8193], progress[128];
  92         char abort_msg[] = "aborting due to possible repository "
  93                 "corruption on the remote side.";
  94         int buffered = -1;
  95
  96         if (pipe(lp_pipe) < 0)
  97                 die("git-upload-pack: unable to create pipe");
  98         pid_rev_list = fork();
  99         if (pid_rev_list < 0)
 100                 die("git-upload-pack: unable to fork git-rev-list");
 101
 102         if (!pid_rev_list) {
 103                 int i;
 104                 int args;
 105                 const char **argv;
 106                 const char **p;
 107                 char *buf;
 108
 109                 if (create_full_pack) {
 110                         args = 10;
 111                         use_thin_pack = 0; /* no point doing it */
 112                 }
 113                 else
 114                         args = have_obj.nr + want_obj.nr + 5;
 115                 p = xmalloc(args * sizeof(char *));
 116                 argv = (const char **) p;
 117                 buf = xmalloc(args * 45);
 118
 119                 dup2(lp_pipe[1], 1);
 120                 close(0);
 121                 close(lp_pipe[0]);
 122                 close(lp_pipe[1]);
 123                 *p++ = "rev-list";
 124                 *p++ = use_thin_pack ? "--objects-edge" : "--objects";
 125                 if (create_full_pack)
 126                         *p++ = "--all";
 127                 else {
 128                         for (i = 0; i < want_obj.nr; i++) {
 129                                 struct object *o = want_obj.objects[i].item;
 130                                 *p++ = buf;
 131                                 memcpy(buf, sha1_to_hex(o->sha1), 41);
 132                                 buf += 41;
 133                         }
 134                 }
 135                 if (!create_full_pack)
 136                         for (i = 0; i < have_obj.nr; i++) {
 137                                 struct object *o = have_obj.objects[i].item;
 138                                 *p++ = buf;
 139                                 *buf++ = '^';
 140                                 memcpy(buf, sha1_to_hex(o->sha1), 41);
 141                                 buf += 41;
 142                         }
 143                 *p++ = NULL;
 144                 execv_git_cmd(argv);
 145                 die("git-upload-pack: unable to exec git-rev-list");
 146         }
 147
 148         if (pipe(pu_pipe) < 0)
 149                 die("git-upload-pack: unable to create pipe");
 150         if (pipe(pe_pipe) < 0)
 151                 die("git-upload-pack: unable to create pipe");
 152         pid_pack_objects = fork();
 153         if (pid_pack_objects < 0) {
 154                 /* daemon sets things up to ignore TERM */
 155                 kill(pid_rev_list, SIGKILL);
 156                 die("git-upload-pack: unable to fork git-pack-objects");
 157         }
 158         if (!pid_pack_objects) {
 159                 dup2(lp_pipe[0], 0);
 160                 dup2(pu_pipe[1], 1);
 161                 dup2(pe_pipe[1], 2);
 162
 163                 close(lp_pipe[0]);
 164                 close(lp_pipe[1]);
 165                 close(pu_pipe[0]);
 166                 close(pu_pipe[1]);
 167                 close(pe_pipe[0]);
 168                 close(pe_pipe[1]);
 169                 execl_git_cmd("pack-objects", "--stdout", "--progress", NULL);
 170                 kill(pid_rev_list, SIGKILL);
 171                 die("git-upload-pack: unable to exec git-pack-objects");
 172         }
 173
 174         close(lp_pipe[0]);
 175         close(lp_pipe[1]);
 176
 177         /* We read from pe_pipe[0] to capture stderr output for
 178          * progress bar, and pu_pipe[0] to capture the pack data.
 179          */
 180         close(pe_pipe[1]);
 181         close(pu_pipe[1]);
 182
 183         while (1) {
 184                 const char *who;
 185                 struct pollfd pfd[2];
 186                 pid_t pid;
 187                 int status;
 188                 ssize_t sz;
 189                 int pe, pu, pollsize;
 190
 191                 reset_timeout();
 192
 193                 pollsize = 0;
 194                 pe = pu = -1;
 195
 196                 if (0 <= pu_pipe[0]) {
 197                         pfd[pollsize].fd = pu_pipe[0];
 198                         pfd[pollsize].events = POLLIN;
 199                         pu = pollsize;
 200                         pollsize++;
 201                 }
 202                 if (0 <= pe_pipe[0]) {
 203                         pfd[pollsize].fd = pe_pipe[0];
 204                         pfd[pollsize].events = POLLIN;
 205                         pe = pollsize;
 206                         pollsize++;
 207                 }
 208
 209                 if (pollsize) {
 210                         if (poll(pfd, pollsize, -1) < 0) {
 211                                 if (errno != EINTR) {
 212                                         error("poll failed, resuming: %s",
 213                                               strerror(errno));
 214                                         sleep(1);
 215                                 }
 216                                 continue;
 217                         }
 218                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 219                                 /* Data ready; we keep the last byte
 220                                  * to ourselves in case we detect
 221                                  * broken rev-list, so that we can
 222                                  * leave the stream corrupted.  This
 223                                  * is unfortunate -- unpack-objects
 224                                  * would happily accept a valid pack
 225                                  * data with trailing garbage, so
 226                                  * appending garbage after we pass all
 227                                  * the pack data is not good enough to
 228                                  * signal breakage to downstream.
 229                                  */
 230                                 char *cp = data;
 231                                 ssize_t outsz = 0;
 232                                 if (0 <= buffered) {
 233                                         *cp++ = buffered;
 234                                         outsz++;
 235                                 }
 236                                 sz = read(pu_pipe[0], cp,
 237                                           sizeof(data) - outsz);
 238                                 if (0 < sz)
 239                                                 ;
 240                                 else if (sz == 0) {
 241                                         close(pu_pipe[0]);
 242                                         pu_pipe[0] = -1;
 243                                 }
 244                                 else
 245                                         goto fail;
 246                                 sz += outsz;
 247                                 if (1 < sz) {
 248                                         buffered = data[sz-1] & 0xFF;
 249                                         sz--;
 250                                 }
 251                                 else
 252                                         buffered = -1;
 253                                 sz = send_client_data(1, data, sz);
 254                                 if (sz < 0)
 255                                         goto fail;
 256                         }
 257                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 258                                 /* Status ready; we ship that in the side-band
 259                                  * or dump to the standard error.
 260                                  */
 261                                 sz = read(pe_pipe[0], progress,
 262                                           sizeof(progress));
 263                                 if (0 < sz)
 264                                         send_client_data(2, progress, sz);
 265                                 else if (sz == 0) {
 266                                         close(pe_pipe[0]);
 267                                         pe_pipe[0] = -1;
 268                                 }
 269                                 else
 270                                         goto fail;
 271                         }
 272                 }
 273
 274                 /* See if the children are still there */
 275                 if (pid_rev_list || pid_pack_objects) {
 276                         pid = waitpid(-1, &status, WNOHANG);
 277                         if (!pid)
 278                                 continue;
 279                         who = ((pid == pid_rev_list) ? "git-rev-list" :
 280                                (pid == pid_pack_objects) ? "git-pack-objects" :
 281                                NULL);
 282                         if (!who) {
 283                                 if (pid < 0) {
 284                                         error("git-upload-pack: %s",
 285                                               strerror(errno));
 286                                         goto fail;
 287                                 }
 288                                 error("git-upload-pack: we weren't "
 289                                       "waiting for %d", pid);
 290                                 continue;
 291                         }
 292                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 293                                 error("git-upload-pack: %s died with error.",
 294                                       who);
 295                                 goto fail;
 296                         }
 297                         if (pid == pid_rev_list)
 298                                 pid_rev_list = 0;
 299                         if (pid == pid_pack_objects)
 300                                 pid_pack_objects = 0;
 301                         if (pid_rev_list || pid_pack_objects)
 302                                 continue;
 303                 }
 304
 305                 /* both died happily */
 306                 if (pollsize)
 307                         continue;
 308
 309                 /* flush the data */
 310                 if (0 <= buffered) {
 311                         data[0] = buffered;
 312                         sz = send_client_data(1, data, 1);
 313                         if (sz < 0)
 314                                 goto fail;
 315                         fprintf(stderr, "flushed.\n");
 316                 }
 317                 send_client_data(1, NULL, 0);
 318                 return;
 319         }
 320  fail:
 321         if (pid_pack_objects)
 322                 kill(pid_pack_objects, SIGKILL);
 323         if (pid_rev_list)
 324                 kill(pid_rev_list, SIGKILL);
 325         send_client_data(3, abort_msg, sizeof(abort_msg));
 326         die("git-upload-pack: %s", abort_msg);
 327 }
 328
 329 static int got_sha1(char *hex, unsigned char *sha1)
 330 {
 331         struct object *o;
 332         int we_knew_they_have = 0;
 333
 334         if (get_sha1_hex(hex, sha1))
 335                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 336         if (!has_sha1_file(sha1))
 337                 return -1;
 338
 339         o = lookup_object(sha1);
 340         if (!(o && o->parsed))
 341                 o = parse_object(sha1);
 342         if (!o)
 343                 die("oops (%s)", sha1_to_hex(sha1));
 344         if (o->type == OBJ_COMMIT) {
 345                 struct commit_list *parents;
 346                 struct commit *commit = (struct commit *)o;
 347                 if (o->flags & THEY_HAVE)
 348                         we_knew_they_have = 1;
 349                 else
 350                         o->flags |= THEY_HAVE;
 351                 if (!oldest_have || (commit->date < oldest_have))
 352                         oldest_have = commit->date;
 353                 for (parents = commit->parents;
 354                      parents;
 355                      parents = parents->next)
 356                         parents->item->object.flags |= THEY_HAVE;
 357         }
 358         if (!we_knew_they_have) {
 359                 add_object_array(o, NULL, &have_obj);
 360                 return 1;
 361         }
 362         return 0;
 363 }
 364
 365 static int reachable(struct commit *want)
 366 {
 367         struct commit_list *work = NULL;
 368
 369         insert_by_date(want, &work);
 370         while (work) {
 371                 struct commit_list *list = work->next;
 372                 struct commit *commit = work->item;
 373                 free(work);
 374                 work = list;
 375
 376                 if (commit->object.flags & THEY_HAVE) {
 377                         want->object.flags |= COMMON_KNOWN;
 378                         break;
 379                 }
 380                 if (!commit->object.parsed)
 381                         parse_object(commit->object.sha1);
 382                 if (commit->object.flags & REACHABLE)
 383                         continue;
 384                 commit->object.flags |= REACHABLE;
 385                 if (commit->date < oldest_have)
 386                         continue;
 387                 for (list = commit->parents; list; list = list->next) {
 388                         struct commit *parent = list->item;
 389                         if (!(parent->object.flags & REACHABLE))
 390                                 insert_by_date(parent, &work);
 391                 }
 392         }
 393         want->object.flags |= REACHABLE;
 394         clear_commit_marks(want, REACHABLE);
 395         free_commit_list(work);
 396         return (want->object.flags & COMMON_KNOWN);
 397 }
 398
 399 static int ok_to_give_up(void)
 400 {
 401         int i;
 402
 403         if (!have_obj.nr)
 404                 return 0;
 405
 406         for (i = 0; i < want_obj.nr; i++) {
 407                 struct object *want = want_obj.objects[i].item;
 408
 409                 if (want->flags & COMMON_KNOWN)
 410                         continue;
 411                 want = deref_tag(want, "a want line", 0);
 412                 if (!want || want->type != OBJ_COMMIT) {
 413                         /* no way to tell if this is reachable by
 414                          * looking at the ancestry chain alone, so
 415                          * leave a note to ourselves not to worry about
 416                          * this object anymore.
 417                          */
 418                         want_obj.objects[i].item->flags |= COMMON_KNOWN;
 419                         continue;
 420                 }
 421                 if (!reachable((struct commit *)want))
 422                         return 0;
 423         }
 424         return 1;
 425 }
 426
 427 static int get_common_commits(void)
 428 {
 429         static char line[1000];
 430         unsigned char sha1[20];
 431         char hex[41], last_hex[41];
 432         int len;
 433
 434         track_object_refs = 0;
 435         save_commit_buffer = 0;
 436
 437         for(;;) {
 438                 len = packet_read_line(0, line, sizeof(line));
 439                 reset_timeout();
 440
 441                 if (!len) {
 442                         if (have_obj.nr == 0 || multi_ack)
 443                                 packet_write(1, "NAK\n");
 444                         continue;
 445                 }
 446                 len = strip(line, len);
 447                 if (!strncmp(line, "have ", 5)) {
 448                         switch (got_sha1(line+5, sha1)) {
 449                         case -1: /* they have what we do not */
 450                                 if (multi_ack && ok_to_give_up())
 451                                         packet_write(1, "ACK %s continue\n",
 452                                                      sha1_to_hex(sha1));
 453                                 break;
 454                         default:
 455                                 memcpy(hex, sha1_to_hex(sha1), 41);
 456                                 if (multi_ack) {
 457                                         const char *msg = "ACK %s continue\n";
 458                                         packet_write(1, msg, hex);
 459                                         memcpy(last_hex, hex, 41);
 460                                 }
 461                                 else if (have_obj.nr == 1)
 462                                         packet_write(1, "ACK %s\n", hex);
 463                                 break;
 464                         }
 465                         continue;
 466                 }
 467                 if (!strcmp(line, "done")) {
 468                         if (have_obj.nr > 0) {
 469                                 if (multi_ack)
 470                                         packet_write(1, "ACK %s\n", last_hex);
 471                                 return 0;
 472                         }
 473                         packet_write(1, "NAK\n");
 474                         return -1;
 475                 }
 476                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 477         }
 478 }
 479
 480 static void receive_needs(void)
 481 {
 482         static char line[1000];
 483         int len;
 484
 485         for (;;) {
 486                 struct object *o;
 487                 unsigned char sha1_buf[20];
 488                 len = packet_read_line(0, line, sizeof(line));
 489                 reset_timeout();
 490                 if (!len)
 491                         return;
 492
 493                 if (strncmp("want ", line, 5) ||
 494                     get_sha1_hex(line+5, sha1_buf))
 495                         die("git-upload-pack: protocol error, "
 496                             "expected to get sha, not '%s'", line);
 497                 if (strstr(line+45, "multi_ack"))
 498                         multi_ack = 1;
 499                 if (strstr(line+45, "thin-pack"))
 500                         use_thin_pack = 1;
 501                 if (strstr(line+45, "side-band"))
 502                         use_sideband = 1;
 503
 504                 /* We have sent all our refs already, and the other end
 505                  * should have chosen out of them; otherwise they are
 506                  * asking for nonsense.
 507                  *
 508                  * Hmph.  We may later want to allow "want" line that
 509                  * asks for something like "master~10" (symbolic)...
 510                  * would it make sense?  I don't know.
 511                  */
 512                 o = lookup_object(sha1_buf);
 513                 if (!o || !(o->flags & OUR_REF))
 514                         die("git-upload-pack: not our ref %s", line+5);
 515                 if (!(o->flags & WANTED)) {
 516                         o->flags |= WANTED;
 517                         add_object_array(o, NULL, &want_obj);
 518                 }
 519         }
 520 }
 521
 522 static int send_ref(const char *refname, const unsigned char *sha1)
 523 {
 524         static const char *capabilities = "multi_ack thin-pack side-band";
 525         struct object *o = parse_object(sha1);
 526
 527         if (!o)
 528                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 529
 530         if (capabilities)
 531                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 532                         0, capabilities);
 533         else
 534                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 535         capabilities = NULL;
 536         if (!(o->flags & OUR_REF)) {
 537                 o->flags |= OUR_REF;
 538                 nr_our_refs++;
 539         }
 540         if (o->type == OBJ_TAG) {
 541                 o = deref_tag(o, refname, 0);
 542                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 543         }
 544         return 0;
 545 }
 546
 547 static int upload_pack(void)
 548 {
 549         reset_timeout();
 550         head_ref(send_ref);
 551         for_each_ref(send_ref);
 552         packet_flush(1);
 553         receive_needs();
 554         if (!want_obj.nr)
 555                 return 0;
 556         get_common_commits();
 557         create_pack_file();
 558         return 0;
 559 }
 560
 561 int main(int argc, char **argv)
 562 {
 563         char *dir;
 564         int i;
 565         int strict = 0;
 566
 567         for (i = 1; i < argc; i++) {
 568                 char *arg = argv[i];
 569
 570                 if (arg[0] != '-')
 571                         break;
 572                 if (!strcmp(arg, "--strict")) {
 573                         strict = 1;
 574                         continue;
 575                 }
 576                 if (!strncmp(arg, "--timeout=", 10)) {
 577                         timeout = atoi(arg+10);
 578                         continue;
 579                 }
 580                 if (!strcmp(arg, "--")) {
 581                         i++;
 582                         break;
 583                 }
 584         }
 585
 586         if (i != argc-1)
 587                 usage(upload_pack_usage);
 588         dir = argv[i];
 589
 590         if (!enter_repo(dir, strict))
 591                 die("'%s': unable to chdir or not a git archive", dir);
 592
 593         upload_pack();
 594         return 0;
 595 }