receive-pack.c

   1 #include "cache.h"
   2 #include "pack.h"
   3 #include "refs.h"
   4 #include "pkt-line.h"
   5 #include "run-command.h"
   6 #include "exec_cmd.h"
   7 #include "commit.h"
   8 #include "object.h"
   9
  10 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
  11
  12 static int deny_non_fast_forwards = 0;
  13 static int receive_fsck_objects;
  14 static int receive_unpack_limit = -1;
  15 static int transfer_unpack_limit = -1;
  16 static int unpack_limit = 100;
  17 static int report_status;
  18
  19 static char capabilities[] = " report-status delete-refs tellme-more ";
  20 static int capabilities_sent;
  21
  22 static int receive_pack_config(const char *var, const char *value)
  23 {
  24         if (strcmp(var, "receive.denynonfastforwards") == 0) {
  25                 deny_non_fast_forwards = git_config_bool(var, value);
  26                 return 0;
  27         }
  28
  29         if (strcmp(var, "receive.unpacklimit") == 0) {
  30                 receive_unpack_limit = git_config_int(var, value);
  31                 return 0;
  32         }
  33
  34         if (strcmp(var, "transfer.unpacklimit") == 0) {
  35                 transfer_unpack_limit = git_config_int(var, value);
  36                 return 0;
  37         }
  38
  39         if (strcmp(var, "receive.fsckobjects") == 0) {
  40                 receive_fsck_objects = git_config_bool(var, value);
  41                 return 0;
  42         }
  43
  44         return git_default_config(var, value);
  45 }
  46
  47 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
  48 {
  49         if (capabilities_sent)
  50                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
  51         else
  52                 packet_write(1, "%s %s%c%s\n",
  53                              sha1_to_hex(sha1), path, 0, capabilities);
  54         capabilities_sent = 1;
  55         return 0;
  56 }
  57
  58 static void write_head_info(void)
  59 {
  60         for_each_ref(show_ref, NULL);
  61         if (!capabilities_sent)
  62                 show_ref("capabilities^{}", null_sha1, 0, NULL);
  63
  64 }
  65
  66 struct command {
  67         struct command *next;
  68         const char *error_string;
  69         unsigned char old_sha1[20];
  70         unsigned char new_sha1[20];
  71         char ref_name[FLEX_ARRAY]; /* more */
  72 };
  73
  74 static struct command *commands;
  75
  76 static const char pre_receive_hook[] = "hooks/pre-receive";
  77 static const char post_receive_hook[] = "hooks/post-receive";
  78
  79 static int hook_status(int code, const char *hook_name)
  80 {
  81         switch (code) {
  82         case 0:
  83                 return 0;
  84         case -ERR_RUN_COMMAND_FORK:
  85                 return error("hook fork failed");
  86         case -ERR_RUN_COMMAND_EXEC:
  87                 return error("hook execute failed");
  88         case -ERR_RUN_COMMAND_PIPE:
  89                 return error("hook pipe failed");
  90         case -ERR_RUN_COMMAND_WAITPID:
  91                 return error("waitpid failed");
  92         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
  93                 return error("waitpid is confused");
  94         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
  95                 return error("%s died of signal", hook_name);
  96         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
  97                 return error("%s died strangely", hook_name);
  98         default:
  99                 error("%s exited with error code %d", hook_name, -code);
 100                 return -code;
 101         }
 102 }
 103
 104 static int run_hook(const char *hook_name)
 105 {
 106         static char buf[sizeof(commands->old_sha1) * 2 + PATH_MAX + 4];
 107         struct command *cmd;
 108         struct child_process proc;
 109         const char *argv[2];
 110         int have_input = 0, code;
 111
 112         for (cmd = commands; !have_input && cmd; cmd = cmd->next) {
 113                 if (!cmd->error_string)
 114                         have_input = 1;
 115         }
 116
 117         if (!have_input || access(hook_name, X_OK) < 0)
 118                 return 0;
 119
 120         argv[0] = hook_name;
 121         argv[1] = NULL;
 122
 123         memset(&proc, 0, sizeof(proc));
 124         proc.argv = argv;
 125         proc.in = -1;
 126         proc.stdout_to_stderr = 1;
 127
 128         code = start_command(&proc);
 129         if (code)
 130                 return hook_status(code, hook_name);
 131         for (cmd = commands; cmd; cmd = cmd->next) {
 132                 if (!cmd->error_string) {
 133                         size_t n = snprintf(buf, sizeof(buf), "%s %s %s\n",
 134                                 sha1_to_hex(cmd->old_sha1),
 135                                 sha1_to_hex(cmd->new_sha1),
 136                                 cmd->ref_name);
 137                         if (write_in_full(proc.in, buf, n) != n)
 138                                 break;
 139                 }
 140         }
 141         close(proc.in);
 142         return hook_status(finish_command(&proc), hook_name);
 143 }
 144
 145 static int run_update_hook(struct command *cmd)
 146 {
 147         static const char update_hook[] = "hooks/update";
 148         struct child_process proc;
 149         const char *argv[5];
 150
 151         if (access(update_hook, X_OK) < 0)
 152                 return 0;
 153
 154         argv[0] = update_hook;
 155         argv[1] = cmd->ref_name;
 156         argv[2] = sha1_to_hex(cmd->old_sha1);
 157         argv[3] = sha1_to_hex(cmd->new_sha1);
 158         argv[4] = NULL;
 159
 160         memset(&proc, 0, sizeof(proc));
 161         proc.argv = argv;
 162         proc.no_stdin = 1;
 163         proc.stdout_to_stderr = 1;
 164
 165         return hook_status(run_command(&proc), update_hook);
 166 }
 167
 168 static const char *update(struct command *cmd)
 169 {
 170         const char *name = cmd->ref_name;
 171         unsigned char *old_sha1 = cmd->old_sha1;
 172         unsigned char *new_sha1 = cmd->new_sha1;
 173         struct ref_lock *lock;
 174
 175         /* only refs/... are allowed */
 176         if (prefixcmp(name, "refs/") || check_ref_format(name + 5)) {
 177                 error("refusing to create funny ref '%s' remotely", name);
 178                 return "funny refname";
 179         }
 180
 181         if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
 182                 error("unpack should have generated %s, "
 183                       "but I can't find it!", sha1_to_hex(new_sha1));
 184                 return "bad pack";
 185         }
 186         if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
 187             !is_null_sha1(old_sha1) &&
 188             !prefixcmp(name, "refs/heads/")) {
 189                 struct object *old_object, *new_object;
 190                 struct commit *old_commit, *new_commit;
 191                 struct commit_list *bases, *ent;
 192
 193                 old_object = parse_object(old_sha1);
 194                 new_object = parse_object(new_sha1);
 195
 196                 if (!old_object || !new_object ||
 197                     old_object->type != OBJ_COMMIT ||
 198                     new_object->type != OBJ_COMMIT) {
 199                         error("bad sha1 objects for %s", name);
 200                         return "bad ref";
 201                 }
 202                 old_commit = (struct commit *)old_object;
 203                 new_commit = (struct commit *)new_object;
 204                 bases = get_merge_bases(old_commit, new_commit, 1);
 205                 for (ent = bases; ent; ent = ent->next)
 206                         if (!hashcmp(old_sha1, ent->item->object.sha1))
 207                                 break;
 208                 free_commit_list(bases);
 209                 if (!ent) {
 210                         error("denying non-fast forward %s"
 211                               " (you should pull first)", name);
 212                         return "non-fast forward";
 213                 }
 214         }
 215         if (run_update_hook(cmd)) {
 216                 error("hook declined to update %s", name);
 217                 return "hook declined";
 218         }
 219
 220         if (is_null_sha1(new_sha1)) {
 221                 if (!parse_object(old_sha1)) {
 222                         warning ("Allowing deletion of corrupt ref.");
 223                         old_sha1 = NULL;
 224                 }
 225                 if (delete_ref(name, old_sha1)) {
 226                         error("failed to delete %s", name);
 227                         return "failed to delete";
 228                 }
 229                 return NULL; /* good */
 230         }
 231         else {
 232                 lock = lock_any_ref_for_update(name, old_sha1, 0);
 233                 if (!lock) {
 234                         error("failed to lock %s", name);
 235                         return "failed to lock";
 236                 }
 237                 if (write_ref_sha1(lock, new_sha1, "push")) {
 238                         return "failed to write"; /* error() already called */
 239                 }
 240                 return NULL; /* good */
 241         }
 242 }
 243
 244 static char update_post_hook[] = "hooks/post-update";
 245
 246 static void run_update_post_hook(struct command *cmd)
 247 {
 248         struct command *cmd_p;
 249         int argc;
 250         const char **argv;
 251
 252         for (argc = 0, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 253                 if (cmd_p->error_string)
 254                         continue;
 255                 argc++;
 256         }
 257         if (!argc || access(update_post_hook, X_OK) < 0)
 258                 return;
 259         argv = xmalloc(sizeof(*argv) * (2 + argc));
 260         argv[0] = update_post_hook;
 261
 262         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 263                 char *p;
 264                 if (cmd_p->error_string)
 265                         continue;
 266                 p = xmalloc(strlen(cmd_p->ref_name) + 1);
 267                 strcpy(p, cmd_p->ref_name);
 268                 argv[argc] = p;
 269                 argc++;
 270         }
 271         argv[argc] = NULL;
 272         run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
 273                 | RUN_COMMAND_STDOUT_TO_STDERR);
 274 }
 275
 276 static void execute_commands(const char *unpacker_error)
 277 {
 278         struct command *cmd = commands;
 279
 280         if (unpacker_error) {
 281                 while (cmd) {
 282                         cmd->error_string = "n/a (unpacker error)";
 283                         cmd = cmd->next;
 284                 }
 285                 return;
 286         }
 287
 288         if (run_hook(pre_receive_hook)) {
 289                 while (cmd) {
 290                         cmd->error_string = "pre-receive hook declined";
 291                         cmd = cmd->next;
 292                 }
 293                 return;
 294         }
 295
 296         while (cmd) {
 297                 cmd->error_string = update(cmd);
 298                 cmd = cmd->next;
 299         }
 300 }
 301
 302 static int parse_tellme_more(char *line, int len, struct commit_list **list)
 303 {
 304         unsigned char sha1[20];
 305         struct commit *c;
 306
 307         if (52 <= len &&
 308             !strncmp(line, "tellme-more ", 12) &&
 309             !get_sha1_hex(line + 12, sha1)) {
 310                 c = lookup_commit_reference_gently(sha1, 1);
 311                 if (c)
 312                         commit_list_insert(c, list);
 313                 return 1;
 314         }
 315         return 0;
 316 }
 317
 318 static void read_head_info(struct commit_list **tellme_more)
 319 {
 320         struct command **p = &commands;
 321         for (;;) {
 322                 static char line[1000];
 323                 unsigned char old_sha1[20], new_sha1[20];
 324                 struct command *cmd;
 325                 char *refname;
 326                 int len, reflen;
 327
 328                 len = packet_read_line(0, line, sizeof(line));
 329                 if (!len)
 330                         break;
 331                 if (line[len-1] == '\n')
 332                         line[--len] = 0;
 333                 if (parse_tellme_more(line, len, tellme_more))
 334                         continue;
 335                 if (len < 83 ||
 336                     line[40] != ' ' ||
 337                     line[81] != ' ' ||
 338                     get_sha1_hex(line, old_sha1) ||
 339                     get_sha1_hex(line + 41, new_sha1))
 340                         die("protocol error: expected old/new/ref, got '%s'",
 341                             line);
 342
 343                 refname = line + 82;
 344                 reflen = strlen(refname);
 345                 if (reflen + 82 < len) {
 346                         if (strstr(refname + reflen + 1, "report-status"))
 347                                 report_status = 1;
 348                 }
 349                 cmd = xmalloc(sizeof(struct command) + len - 80);
 350                 hashcpy(cmd->old_sha1, old_sha1);
 351                 hashcpy(cmd->new_sha1, new_sha1);
 352                 memcpy(cmd->ref_name, line + 82, len - 81);
 353                 cmd->error_string = NULL;
 354                 cmd->next = NULL;
 355                 *p = cmd;
 356                 p = &cmd->next;
 357         }
 358 }
 359
 360 static void sender_wants_more(struct commit_list **tellme_more)
 361 {
 362         char line[1024];
 363         int len;
 364
 365         while (1) {
 366                 len = packet_read_line(0, line, sizeof(line));
 367                 if (!len)
 368                         return;
 369                 if (line[len-1] == '\n')
 370                         line[--len] = '\0';
 371                 if (parse_tellme_more(line, len, tellme_more))
 372                         continue;
 373                 /* ignore other responses for future extension */
 374         }
 375 }
 376
 377 #define SHOWN_TO_SENDER (1<<20)
 378 static struct commit_list **add_parents(struct commit *commit, struct commit_list **tail, int round)
 379 {
 380         struct commit_list *parents = commit->parents;
 381
 382         /*
 383          * In round N, we will send one commit for every (N+1)^2
 384          * commits in single parent chain to optimize for very stale
 385          * pushers.
 386          */
 387         round *= round;
 388         while (round--) {
 389                 if (!parents || (parents && parents->next))
 390                         break; /* do not skip merges */
 391                 commit = parents->item;
 392                 if (parse_commit(commit))
 393                         return tail; /* oops */
 394                 if (!commit->parents)
 395                         break; /* do not skip root */
 396                 /*
 397                  * Before skipping this commit, mark it so that
 398                  * later clear_commit_marks() can clear its ancestors.
 399                  */
 400                 commit->object.flags |= SHOWN_TO_SENDER;
 401                 parents = commit->parents;
 402         }
 403
 404         while (parents) {
 405                 commit = parents->item;
 406                 parents = parents->next;
 407                 if (commit->object.flags & SHOWN_TO_SENDER)
 408                         continue;
 409                 if (parse_commit(commit))
 410                         continue;
 411                 tail = &commit_list_insert(commit, tail)->next;
 412         }
 413         return tail;
 414 }
 415
 416 #define BATCH 20
 417 static void send_ancestors(struct commit *commit, int round)
 418 {
 419         struct commit_list *list = NULL;
 420         struct commit_list **tail = &list;
 421         int count = 0;
 422
 423         tail = &commit_list_insert(commit, tail)->next;
 424         while (list && count < BATCH) {
 425                 struct commit_list *elem = list;
 426                 struct commit *c = elem->item;
 427
 428                 list = list->next;
 429                 free(elem);
 430                 if (!list)
 431                         tail = &list;
 432
 433                 if (c->object.flags & SHOWN_TO_SENDER)
 434                         continue;
 435                 if (parse_commit(c))
 436                         continue;
 437                 c->object.flags |= SHOWN_TO_SENDER;
 438                 if (c != commit) {
 439                         packet_write(1, "%s %s\n",
 440                                      sha1_to_hex(c->object.sha1),
 441                                      sha1_to_hex(commit->object.sha1));
 442                         count++;
 443                 }
 444                 tail = add_parents(c, tail, round);
 445         }
 446         clear_commit_marks(commit, SHOWN_TO_SENDER);
 447         free_commit_list(list);
 448 }
 449
 450 #define MAX_ROUND 5
 451 static void exchange_history(struct commit_list *list)
 452 {
 453         int round = 0;
 454
 455         while (list) {
 456                 while (list) {
 457                         struct commit_list *elem = list;
 458                         struct commit *commit = elem->item;
 459
 460                         list = list->next;
 461                         free(elem);
 462
 463                         /*
 464                          * The sender does not know about commit and asks its
 465                          * ancestors to be sent.
 466                          */
 467                         if (parse_commit(commit))
 468                                 continue;
 469
 470                         send_ancestors(commit, round);
 471                 }
 472                 packet_flush(1); /* have you heard enough? */
 473
 474                 sender_wants_more(&list);
 475                 round++;
 476                 if (MAX_ROUND < round) {
 477                         while (list) {
 478                                 /* sorry, no more */
 479                                 packet_flush(1);
 480                                 free_commit_list(list);
 481                                 list = NULL;
 482                                 /* wait until the other end gives up */
 483                                 sender_wants_more(&list);
 484                         }
 485                         break;
 486                 }
 487         }
 488 }
 489
 490 static const char *parse_pack_header(struct pack_header *hdr)
 491 {
 492         switch (read_pack_header(0, hdr)) {
 493         case PH_ERROR_EOF:
 494                 return "eof before pack header was fully read";
 495
 496         case PH_ERROR_PACK_SIGNATURE:
 497                 return "protocol error (pack signature mismatch detected)";
 498
 499         case PH_ERROR_PROTOCOL:
 500                 return "protocol error (pack version unsupported)";
 501
 502         default:
 503                 return "unknown error in parse_pack_header";
 504
 505         case 0:
 506                 return NULL;
 507         }
 508 }
 509
 510 static const char *pack_lockfile;
 511
 512 static const char *unpack(void)
 513 {
 514         struct pack_header hdr;
 515         const char *hdr_err;
 516         char hdr_arg[38];
 517
 518         hdr_err = parse_pack_header(&hdr);
 519         if (hdr_err)
 520                 return hdr_err;
 521         snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
 522                         ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
 523
 524         if (ntohl(hdr.hdr_entries) < unpack_limit) {
 525                 int code, i = 0;
 526                 const char *unpacker[4];
 527                 unpacker[i++] = "unpack-objects";
 528                 if (receive_fsck_objects)
 529                         unpacker[i++] = "--strict";
 530                 unpacker[i++] = hdr_arg;
 531                 unpacker[i++] = NULL;
 532                 code = run_command_v_opt(unpacker, RUN_GIT_CMD);
 533                 switch (code) {
 534                 case 0:
 535                         return NULL;
 536                 case -ERR_RUN_COMMAND_FORK:
 537                         return "unpack fork failed";
 538                 case -ERR_RUN_COMMAND_EXEC:
 539                         return "unpack execute failed";
 540                 case -ERR_RUN_COMMAND_WAITPID:
 541                         return "waitpid failed";
 542                 case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
 543                         return "waitpid is confused";
 544                 case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
 545                         return "unpacker died of signal";
 546                 case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
 547                         return "unpacker died strangely";
 548                 default:
 549                         return "unpacker exited with error code";
 550                 }
 551         } else {
 552                 const char *keeper[7];
 553                 int s, status, i = 0;
 554                 char keep_arg[256];
 555                 struct child_process ip;
 556
 557                 s = sprintf(keep_arg, "--keep=receive-pack %i on ", getpid());
 558                 if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 559                         strcpy(keep_arg + s, "localhost");
 560
 561                 keeper[i++] = "index-pack";
 562                 keeper[i++] = "--stdin";
 563                 if (receive_fsck_objects)
 564                         keeper[i++] = "--strict";
 565                 keeper[i++] = "--fix-thin";
 566                 keeper[i++] = hdr_arg;
 567                 keeper[i++] = keep_arg;
 568                 keeper[i++] = NULL;
 569                 memset(&ip, 0, sizeof(ip));
 570                 ip.argv = keeper;
 571                 ip.out = -1;
 572                 ip.git_cmd = 1;
 573                 if (start_command(&ip))
 574                         return "index-pack fork failed";
 575                 pack_lockfile = index_pack_lockfile(ip.out);
 576                 close(ip.out);
 577                 status = finish_command(&ip);
 578                 if (!status) {
 579                         reprepare_packed_git();
 580                         return NULL;
 581                 }
 582                 return "index-pack abnormal exit";
 583         }
 584 }
 585
 586 static void report(const char *unpack_status)
 587 {
 588         struct command *cmd;
 589         packet_write(1, "unpack %s\n",
 590                      unpack_status ? unpack_status : "ok");
 591         for (cmd = commands; cmd; cmd = cmd->next) {
 592                 if (!cmd->error_string)
 593                         packet_write(1, "ok %s\n",
 594                                      cmd->ref_name);
 595                 else
 596                         packet_write(1, "ng %s %s\n",
 597                                      cmd->ref_name, cmd->error_string);
 598         }
 599         packet_flush(1);
 600 }
 601
 602 static int delete_only(struct command *cmd)
 603 {
 604         while (cmd) {
 605                 if (!is_null_sha1(cmd->new_sha1))
 606                         return 0;
 607                 cmd = cmd->next;
 608         }
 609         return 1;
 610 }
 611
 612 int main(int argc, char **argv)
 613 {
 614         int i;
 615         char *dir = NULL;
 616         struct commit_list *tellme_more = NULL;
 617
 618         argv++;
 619         for (i = 1; i < argc; i++) {
 620                 char *arg = *argv++;
 621
 622                 if (*arg == '-') {
 623                         /* Do flag handling here */
 624                         usage(receive_pack_usage);
 625                 }
 626                 if (dir)
 627                         usage(receive_pack_usage);
 628                 dir = arg;
 629         }
 630         if (!dir)
 631                 usage(receive_pack_usage);
 632
 633         setup_path(NULL);
 634
 635         if (!enter_repo(dir, 0))
 636                 die("'%s': unable to chdir or not a git archive", dir);
 637
 638         if (is_repository_shallow())
 639                 die("attempt to push into a shallow repository");
 640
 641         git_config(receive_pack_config);
 642
 643         if (0 <= transfer_unpack_limit)
 644                 unpack_limit = transfer_unpack_limit;
 645         else if (0 <= receive_unpack_limit)
 646                 unpack_limit = receive_unpack_limit;
 647
 648         write_head_info();
 649
 650         /* EOF */
 651         packet_flush(1);
 652
 653         read_head_info(&tellme_more);
 654
 655         if (tellme_more)
 656                 exchange_history(tellme_more);
 657
 658         if (commands) {
 659                 const char *unpack_status = NULL;
 660
 661                 if (!delete_only(commands))
 662                         unpack_status = unpack();
 663                 execute_commands(unpack_status);
 664                 if (pack_lockfile)
 665                         unlink(pack_lockfile);
 666                 if (report_status)
 667                         report(unpack_status);
 668                 run_hook(post_receive_hook);
 669                 run_update_post_hook(commands);
 670         }
 671         return 0;
 672 }