builtin/receive-pack.c

   1 #include "builtin.h"
   2 #include "pack.h"
   3 #include "refs.h"
   4 #include "pkt-line.h"
   5 #include "sideband.h"
   6 #include "run-command.h"
   7 #include "exec_cmd.h"
   8 #include "commit.h"
   9 #include "object.h"
  10 #include "remote.h"
  11 #include "transport.h"
  12 #include "string-list.h"
  13 #include "sha1-array.h"
  14 #include "connected.h"
  15
  16 static const char receive_pack_usage[] = "git receive-pack <git-dir>";
  17
  18 enum deny_action {
  19         DENY_UNCONFIGURED,
  20         DENY_IGNORE,
  21         DENY_WARN,
  22         DENY_REFUSE
  23 };
  24
  25 static int deny_deletes;
  26 static int deny_non_fast_forwards;
  27 static enum deny_action deny_current_branch = DENY_UNCONFIGURED;
  28 static enum deny_action deny_delete_current = DENY_UNCONFIGURED;
  29 static int receive_fsck_objects = -1;
  30 static int transfer_fsck_objects = -1;
  31 static int receive_unpack_limit = -1;
  32 static int transfer_unpack_limit = -1;
  33 static int unpack_limit = 100;
  34 static int report_status;
  35 static int use_sideband;
  36 static int prefer_ofs_delta = 1;
  37 static int auto_update_server_info;
  38 static int auto_gc = 1;
  39 static const char *head_name;
  40 static int sent_capabilities;
  41
  42 static enum deny_action parse_deny_action(const char *var, const char *value)
  43 {
  44         if (value) {
  45                 if (!strcasecmp(value, "ignore"))
  46                         return DENY_IGNORE;
  47                 if (!strcasecmp(value, "warn"))
  48                         return DENY_WARN;
  49                 if (!strcasecmp(value, "refuse"))
  50                         return DENY_REFUSE;
  51         }
  52         if (git_config_bool(var, value))
  53                 return DENY_REFUSE;
  54         return DENY_IGNORE;
  55 }
  56
  57 static int receive_pack_config(const char *var, const char *value, void *cb)
  58 {
  59         if (strcmp(var, "receive.denydeletes") == 0) {
  60                 deny_deletes = git_config_bool(var, value);
  61                 return 0;
  62         }
  63
  64         if (strcmp(var, "receive.denynonfastforwards") == 0) {
  65                 deny_non_fast_forwards = git_config_bool(var, value);
  66                 return 0;
  67         }
  68
  69         if (strcmp(var, "receive.unpacklimit") == 0) {
  70                 receive_unpack_limit = git_config_int(var, value);
  71                 return 0;
  72         }
  73
  74         if (strcmp(var, "transfer.unpacklimit") == 0) {
  75                 transfer_unpack_limit = git_config_int(var, value);
  76                 return 0;
  77         }
  78
  79         if (strcmp(var, "receive.fsckobjects") == 0) {
  80                 receive_fsck_objects = git_config_bool(var, value);
  81                 return 0;
  82         }
  83
  84         if (strcmp(var, "transfer.fsckobjects") == 0) {
  85                 transfer_fsck_objects = git_config_bool(var, value);
  86                 return 0;
  87         }
  88
  89         if (!strcmp(var, "receive.denycurrentbranch")) {
  90                 deny_current_branch = parse_deny_action(var, value);
  91                 return 0;
  92         }
  93
  94         if (strcmp(var, "receive.denydeletecurrent") == 0) {
  95                 deny_delete_current = parse_deny_action(var, value);
  96                 return 0;
  97         }
  98
  99         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 100                 prefer_ofs_delta = git_config_bool(var, value);
 101                 return 0;
 102         }
 103
 104         if (strcmp(var, "receive.updateserverinfo") == 0) {
 105                 auto_update_server_info = git_config_bool(var, value);
 106                 return 0;
 107         }
 108
 109         if (strcmp(var, "receive.autogc") == 0) {
 110                 auto_gc = git_config_bool(var, value);
 111                 return 0;
 112         }
 113
 114         return git_default_config(var, value, cb);
 115 }
 116
 117 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 118 {
 119         if (sent_capabilities)
 120                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
 121         else
 122                 packet_write(1, "%s %s%c%s%s\n",
 123                              sha1_to_hex(sha1), path, 0,
 124                              " report-status delete-refs side-band-64k",
 125                              prefer_ofs_delta ? " ofs-delta" : "");
 126         sent_capabilities = 1;
 127         return 0;
 128 }
 129
 130 static int show_ref_cb(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 131 {
 132         path = strip_namespace(path);
 133         /*
 134          * Advertise refs outside our current namespace as ".have"
 135          * refs, so that the client can use them to minimize data
 136          * transfer but will otherwise ignore them. This happens to
 137          * cover ".have" that are thrown in by add_one_alternate_ref()
 138          * to mark histories that are complete in our alternates as
 139          * well.
 140          */
 141         if (!path)
 142                 path = ".have";
 143         return show_ref(path, sha1, flag, cb_data);
 144 }
 145
 146 static void write_head_info(void)
 147 {
 148         for_each_ref(show_ref_cb, NULL);
 149         if (!sent_capabilities)
 150                 show_ref("capabilities^{}", null_sha1, 0, NULL);
 151
 152 }
 153
 154 struct command {
 155         struct command *next;
 156         const char *error_string;
 157         unsigned int skip_update:1,
 158                      did_not_exist:1;
 159         unsigned char old_sha1[20];
 160         unsigned char new_sha1[20];
 161         char ref_name[FLEX_ARRAY]; /* more */
 162 };
 163
 164 static const char pre_receive_hook[] = "hooks/pre-receive";
 165 static const char post_receive_hook[] = "hooks/post-receive";
 166
 167 static void rp_error(const char *err, ...) __attribute__((format (printf, 1, 2)));
 168 static void rp_warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
 169
 170 static void report_message(const char *prefix, const char *err, va_list params)
 171 {
 172         int sz = strlen(prefix);
 173         char msg[4096];
 174
 175         strncpy(msg, prefix, sz);
 176         sz += vsnprintf(msg + sz, sizeof(msg) - sz, err, params);
 177         if (sz > (sizeof(msg) - 1))
 178                 sz = sizeof(msg) - 1;
 179         msg[sz++] = '\n';
 180
 181         if (use_sideband)
 182                 send_sideband(1, 2, msg, sz, use_sideband);
 183         else
 184                 xwrite(2, msg, sz);
 185 }
 186
 187 static void rp_warning(const char *err, ...)
 188 {
 189         va_list params;
 190         va_start(params, err);
 191         report_message("warning: ", err, params);
 192         va_end(params);
 193 }
 194
 195 static void rp_error(const char *err, ...)
 196 {
 197         va_list params;
 198         va_start(params, err);
 199         report_message("error: ", err, params);
 200         va_end(params);
 201 }
 202
 203 static int copy_to_sideband(int in, int out, void *arg)
 204 {
 205         char data[128];
 206         while (1) {
 207                 ssize_t sz = xread(in, data, sizeof(data));
 208                 if (sz <= 0)
 209                         break;
 210                 send_sideband(1, 2, data, sz, use_sideband);
 211         }
 212         close(in);
 213         return 0;
 214 }
 215
 216 typedef int (*feed_fn)(void *, const char **, size_t *);
 217 static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state)
 218 {
 219         struct child_process proc;
 220         struct async muxer;
 221         const char *argv[2];
 222         int code;
 223
 224         if (access(hook_name, X_OK) < 0)
 225                 return 0;
 226
 227         argv[0] = hook_name;
 228         argv[1] = NULL;
 229
 230         memset(&proc, 0, sizeof(proc));
 231         proc.argv = argv;
 232         proc.in = -1;
 233         proc.stdout_to_stderr = 1;
 234
 235         if (use_sideband) {
 236                 memset(&muxer, 0, sizeof(muxer));
 237                 muxer.proc = copy_to_sideband;
 238                 muxer.in = -1;
 239                 code = start_async(&muxer);
 240                 if (code)
 241                         return code;
 242                 proc.err = muxer.in;
 243         }
 244
 245         code = start_command(&proc);
 246         if (code) {
 247                 if (use_sideband)
 248                         finish_async(&muxer);
 249                 return code;
 250         }
 251
 252         while (1) {
 253                 const char *buf;
 254                 size_t n;
 255                 if (feed(feed_state, &buf, &n))
 256                         break;
 257                 if (write_in_full(proc.in, buf, n) != n)
 258                         break;
 259         }
 260         close(proc.in);
 261         if (use_sideband)
 262                 finish_async(&muxer);
 263         return finish_command(&proc);
 264 }
 265
 266 struct receive_hook_feed_state {
 267         struct command *cmd;
 268         int skip_broken;
 269         struct strbuf buf;
 270 };
 271
 272 static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
 273 {
 274         struct receive_hook_feed_state *state = state_;
 275         struct command *cmd = state->cmd;
 276
 277         while (cmd &&
 278                state->skip_broken && (cmd->error_string || cmd->did_not_exist))
 279                 cmd = cmd->next;
 280         if (!cmd)
 281                 return -1; /* EOF */
 282         strbuf_reset(&state->buf);
 283         strbuf_addf(&state->buf, "%s %s %s\n",
 284                     sha1_to_hex(cmd->old_sha1), sha1_to_hex(cmd->new_sha1),
 285                     cmd->ref_name);
 286         state->cmd = cmd->next;
 287         if (bufp) {
 288                 *bufp = state->buf.buf;
 289                 *sizep = state->buf.len;
 290         }
 291         return 0;
 292 }
 293
 294 static int run_receive_hook(struct command *commands, const char *hook_name,
 295                             int skip_broken)
 296 {
 297         struct receive_hook_feed_state state;
 298         int status;
 299
 300         strbuf_init(&state.buf, 0);
 301         state.cmd = commands;
 302         state.skip_broken = skip_broken;
 303         if (feed_receive_hook(&state, NULL, NULL))
 304                 return 0;
 305         state.cmd = commands;
 306         status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
 307         strbuf_release(&state.buf);
 308         return status;
 309 }
 310
 311 static int run_update_hook(struct command *cmd)
 312 {
 313         static const char update_hook[] = "hooks/update";
 314         const char *argv[5];
 315         struct child_process proc;
 316         int code;
 317
 318         if (access(update_hook, X_OK) < 0)
 319                 return 0;
 320
 321         argv[0] = update_hook;
 322         argv[1] = cmd->ref_name;
 323         argv[2] = sha1_to_hex(cmd->old_sha1);
 324         argv[3] = sha1_to_hex(cmd->new_sha1);
 325         argv[4] = NULL;
 326
 327         memset(&proc, 0, sizeof(proc));
 328         proc.no_stdin = 1;
 329         proc.stdout_to_stderr = 1;
 330         proc.err = use_sideband ? -1 : 0;
 331         proc.argv = argv;
 332
 333         code = start_command(&proc);
 334         if (code)
 335                 return code;
 336         if (use_sideband)
 337                 copy_to_sideband(proc.err, -1, NULL);
 338         return finish_command(&proc);
 339 }
 340
 341 static int is_ref_checked_out(const char *ref)
 342 {
 343         if (is_bare_repository())
 344                 return 0;
 345
 346         if (!head_name)
 347                 return 0;
 348         return !strcmp(head_name, ref);
 349 }
 350
 351 static char *refuse_unconfigured_deny_msg[] = {
 352         "By default, updating the current branch in a non-bare repository",
 353         "is denied, because it will make the index and work tree inconsistent",
 354         "with what you pushed, and will require 'git reset --hard' to match",
 355         "the work tree to HEAD.",
 356         "",
 357         "You can set 'receive.denyCurrentBranch' configuration variable to",
 358         "'ignore' or 'warn' in the remote repository to allow pushing into",
 359         "its current branch; however, this is not recommended unless you",
 360         "arranged to update its work tree to match what you pushed in some",
 361         "other way.",
 362         "",
 363         "To squelch this message and still keep the default behaviour, set",
 364         "'receive.denyCurrentBranch' configuration variable to 'refuse'."
 365 };
 366
 367 static void refuse_unconfigured_deny(void)
 368 {
 369         int i;
 370         for (i = 0; i < ARRAY_SIZE(refuse_unconfigured_deny_msg); i++)
 371                 rp_error("%s", refuse_unconfigured_deny_msg[i]);
 372 }
 373
 374 static char *refuse_unconfigured_deny_delete_current_msg[] = {
 375         "By default, deleting the current branch is denied, because the next",
 376         "'git clone' won't result in any file checked out, causing confusion.",
 377         "",
 378         "You can set 'receive.denyDeleteCurrent' configuration variable to",
 379         "'warn' or 'ignore' in the remote repository to allow deleting the",
 380         "current branch, with or without a warning message.",
 381         "",
 382         "To squelch this message, you can set it to 'refuse'."
 383 };
 384
 385 static void refuse_unconfigured_deny_delete_current(void)
 386 {
 387         int i;
 388         for (i = 0;
 389              i < ARRAY_SIZE(refuse_unconfigured_deny_delete_current_msg);
 390              i++)
 391                 rp_error("%s", refuse_unconfigured_deny_delete_current_msg[i]);
 392 }
 393
 394 static const char *update(struct command *cmd)
 395 {
 396         const char *name = cmd->ref_name;
 397         struct strbuf namespaced_name_buf = STRBUF_INIT;
 398         const char *namespaced_name;
 399         unsigned char *old_sha1 = cmd->old_sha1;
 400         unsigned char *new_sha1 = cmd->new_sha1;
 401         struct ref_lock *lock;
 402
 403         /* only refs/... are allowed */
 404         if (prefixcmp(name, "refs/") || check_refname_format(name + 5, 0)) {
 405                 rp_error("refusing to create funny ref '%s' remotely", name);
 406                 return "funny refname";
 407         }
 408
 409         strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
 410         namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
 411
 412         if (is_ref_checked_out(namespaced_name)) {
 413                 switch (deny_current_branch) {
 414                 case DENY_IGNORE:
 415                         break;
 416                 case DENY_WARN:
 417                         rp_warning("updating the current branch");
 418                         break;
 419                 case DENY_REFUSE:
 420                 case DENY_UNCONFIGURED:
 421                         rp_error("refusing to update checked out branch: %s", name);
 422                         if (deny_current_branch == DENY_UNCONFIGURED)
 423                                 refuse_unconfigured_deny();
 424                         return "branch is currently checked out";
 425                 }
 426         }
 427
 428         if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
 429                 error("unpack should have generated %s, "
 430                       "but I can't find it!", sha1_to_hex(new_sha1));
 431                 return "bad pack";
 432         }
 433
 434         if (!is_null_sha1(old_sha1) && is_null_sha1(new_sha1)) {
 435                 if (deny_deletes && !prefixcmp(name, "refs/heads/")) {
 436                         rp_error("denying ref deletion for %s", name);
 437                         return "deletion prohibited";
 438                 }
 439
 440                 if (!strcmp(namespaced_name, head_name)) {
 441                         switch (deny_delete_current) {
 442                         case DENY_IGNORE:
 443                                 break;
 444                         case DENY_WARN:
 445                                 rp_warning("deleting the current branch");
 446                                 break;
 447                         case DENY_REFUSE:
 448                         case DENY_UNCONFIGURED:
 449                                 if (deny_delete_current == DENY_UNCONFIGURED)
 450                                         refuse_unconfigured_deny_delete_current();
 451                                 rp_error("refusing to delete the current branch: %s", name);
 452                                 return "deletion of the current branch prohibited";
 453                         }
 454                 }
 455         }
 456
 457         if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
 458             !is_null_sha1(old_sha1) &&
 459             !prefixcmp(name, "refs/heads/")) {
 460                 struct object *old_object, *new_object;
 461                 struct commit *old_commit, *new_commit;
 462                 struct commit_list *bases, *ent;
 463
 464                 old_object = parse_object(old_sha1);
 465                 new_object = parse_object(new_sha1);
 466
 467                 if (!old_object || !new_object ||
 468                     old_object->type != OBJ_COMMIT ||
 469                     new_object->type != OBJ_COMMIT) {
 470                         error("bad sha1 objects for %s", name);
 471                         return "bad ref";
 472                 }
 473                 old_commit = (struct commit *)old_object;
 474                 new_commit = (struct commit *)new_object;
 475                 bases = get_merge_bases(old_commit, new_commit, 1);
 476                 for (ent = bases; ent; ent = ent->next)
 477                         if (!hashcmp(old_sha1, ent->item->object.sha1))
 478                                 break;
 479                 free_commit_list(bases);
 480                 if (!ent) {
 481                         rp_error("denying non-fast-forward %s"
 482                                  " (you should pull first)", name);
 483                         return "non-fast-forward";
 484                 }
 485         }
 486         if (run_update_hook(cmd)) {
 487                 rp_error("hook declined to update %s", name);
 488                 return "hook declined";
 489         }
 490
 491         if (is_null_sha1(new_sha1)) {
 492                 if (!parse_object(old_sha1)) {
 493                         old_sha1 = NULL;
 494                         if (ref_exists(name)) {
 495                                 rp_warning("Allowing deletion of corrupt ref.");
 496                         } else {
 497                                 rp_warning("Deleting a non-existent ref.");
 498                                 cmd->did_not_exist = 1;
 499                         }
 500                 }
 501                 if (delete_ref(namespaced_name, old_sha1, 0)) {
 502                         rp_error("failed to delete %s", name);
 503                         return "failed to delete";
 504                 }
 505                 return NULL; /* good */
 506         }
 507         else {
 508                 lock = lock_any_ref_for_update(namespaced_name, old_sha1, 0);
 509                 if (!lock) {
 510                         rp_error("failed to lock %s", name);
 511                         return "failed to lock";
 512                 }
 513                 if (write_ref_sha1(lock, new_sha1, "push")) {
 514                         return "failed to write"; /* error() already called */
 515                 }
 516                 return NULL; /* good */
 517         }
 518 }
 519
 520 static char update_post_hook[] = "hooks/post-update";
 521
 522 static void run_update_post_hook(struct command *commands)
 523 {
 524         struct command *cmd;
 525         int argc;
 526         const char **argv;
 527         struct child_process proc;
 528
 529         for (argc = 0, cmd = commands; cmd; cmd = cmd->next) {
 530                 if (cmd->error_string || cmd->did_not_exist)
 531                         continue;
 532                 argc++;
 533         }
 534         if (!argc || access(update_post_hook, X_OK) < 0)
 535                 return;
 536         argv = xmalloc(sizeof(*argv) * (2 + argc));
 537         argv[0] = update_post_hook;
 538
 539         for (argc = 1, cmd = commands; cmd; cmd = cmd->next) {
 540                 char *p;
 541                 if (cmd->error_string || cmd->did_not_exist)
 542                         continue;
 543                 p = xmalloc(strlen(cmd->ref_name) + 1);
 544                 strcpy(p, cmd->ref_name);
 545                 argv[argc] = p;
 546                 argc++;
 547         }
 548         argv[argc] = NULL;
 549
 550         memset(&proc, 0, sizeof(proc));
 551         proc.no_stdin = 1;
 552         proc.stdout_to_stderr = 1;
 553         proc.err = use_sideband ? -1 : 0;
 554         proc.argv = argv;
 555
 556         if (!start_command(&proc)) {
 557                 if (use_sideband)
 558                         copy_to_sideband(proc.err, -1, NULL);
 559                 finish_command(&proc);
 560         }
 561 }
 562
 563 static void check_aliased_update(struct command *cmd, struct string_list *list)
 564 {
 565         struct strbuf buf = STRBUF_INIT;
 566         const char *dst_name;
 567         struct string_list_item *item;
 568         struct command *dst_cmd;
 569         unsigned char sha1[20];
 570         char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41];
 571         int flag;
 572
 573         strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
 574         dst_name = resolve_ref(buf.buf, sha1, 0, &flag);
 575         strbuf_release(&buf);
 576
 577         if (!(flag & REF_ISSYMREF))
 578                 return;
 579
 580         dst_name = strip_namespace(dst_name);
 581         if (!dst_name) {
 582                 rp_error("refusing update to broken symref '%s'", cmd->ref_name);
 583                 cmd->skip_update = 1;
 584                 cmd->error_string = "broken symref";
 585                 return;
 586         }
 587
 588         if ((item = string_list_lookup(list, dst_name)) == NULL)
 589                 return;
 590
 591         cmd->skip_update = 1;
 592
 593         dst_cmd = (struct command *) item->util;
 594
 595         if (!hashcmp(cmd->old_sha1, dst_cmd->old_sha1) &&
 596             !hashcmp(cmd->new_sha1, dst_cmd->new_sha1))
 597                 return;
 598
 599         dst_cmd->skip_update = 1;
 600
 601         strcpy(cmd_oldh, find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV));
 602         strcpy(cmd_newh, find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV));
 603         strcpy(dst_oldh, find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV));
 604         strcpy(dst_newh, find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV));
 605         rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
 606                  " its target '%s' (%s..%s)",
 607                  cmd->ref_name, cmd_oldh, cmd_newh,
 608                  dst_cmd->ref_name, dst_oldh, dst_newh);
 609
 610         cmd->error_string = dst_cmd->error_string =
 611                 "inconsistent aliased update";
 612 }
 613
 614 static void check_aliased_updates(struct command *commands)
 615 {
 616         struct command *cmd;
 617         struct string_list ref_list = STRING_LIST_INIT_NODUP;
 618
 619         for (cmd = commands; cmd; cmd = cmd->next) {
 620                 struct string_list_item *item =
 621                         string_list_append(&ref_list, cmd->ref_name);
 622                 item->util = (void *)cmd;
 623         }
 624         sort_string_list(&ref_list);
 625
 626         for (cmd = commands; cmd; cmd = cmd->next)
 627                 check_aliased_update(cmd, &ref_list);
 628
 629         string_list_clear(&ref_list, 0);
 630 }
 631
 632 static int command_singleton_iterator(void *cb_data, unsigned char sha1[20])
 633 {
 634         struct command **cmd_list = cb_data;
 635         struct command *cmd = *cmd_list;
 636
 637         if (!cmd || is_null_sha1(cmd->new_sha1))
 638                 return -1; /* end of list */
 639         *cmd_list = NULL; /* this returns only one */
 640         hashcpy(sha1, cmd->new_sha1);
 641         return 0;
 642 }
 643
 644 static void set_connectivity_errors(struct command *commands)
 645 {
 646         struct command *cmd;
 647
 648         for (cmd = commands; cmd; cmd = cmd->next) {
 649                 struct command *singleton = cmd;
 650                 if (!check_everything_connected(command_singleton_iterator,
 651                                                 0, &singleton))
 652                         continue;
 653                 cmd->error_string = "missing necessary objects";
 654         }
 655 }
 656
 657 static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
 658 {
 659         struct command **cmd_list = cb_data;
 660         struct command *cmd = *cmd_list;
 661
 662         while (cmd) {
 663                 if (!is_null_sha1(cmd->new_sha1)) {
 664                         hashcpy(sha1, cmd->new_sha1);
 665                         *cmd_list = cmd->next;
 666                         return 0;
 667                 }
 668                 cmd = cmd->next;
 669         }
 670         *cmd_list = NULL;
 671         return -1; /* end of list */
 672 }
 673
 674 static void execute_commands(struct command *commands, const char *unpacker_error)
 675 {
 676         struct command *cmd;
 677         unsigned char sha1[20];
 678
 679         if (unpacker_error) {
 680                 for (cmd = commands; cmd; cmd = cmd->next)
 681                         cmd->error_string = "n/a (unpacker error)";
 682                 return;
 683         }
 684
 685         cmd = commands;
 686         if (check_everything_connected(iterate_receive_command_list,
 687                                        0, &cmd))
 688                 set_connectivity_errors(commands);
 689
 690         if (run_receive_hook(commands, pre_receive_hook, 0)) {
 691                 for (cmd = commands; cmd; cmd = cmd->next)
 692                         cmd->error_string = "pre-receive hook declined";
 693                 return;
 694         }
 695
 696         check_aliased_updates(commands);
 697
 698         head_name = resolve_ref("HEAD", sha1, 0, NULL);
 699
 700         for (cmd = commands; cmd; cmd = cmd->next)
 701                 if (!cmd->skip_update)
 702                         cmd->error_string = update(cmd);
 703 }
 704
 705 static struct command *read_head_info(void)
 706 {
 707         struct command *commands = NULL;
 708         struct command **p = &commands;
 709         for (;;) {
 710                 static char line[1000];
 711                 unsigned char old_sha1[20], new_sha1[20];
 712                 struct command *cmd;
 713                 char *refname;
 714                 int len, reflen;
 715
 716                 len = packet_read_line(0, line, sizeof(line));
 717                 if (!len)
 718                         break;
 719                 if (line[len-1] == '\n')
 720                         line[--len] = 0;
 721                 if (len < 83 ||
 722                     line[40] != ' ' ||
 723                     line[81] != ' ' ||
 724                     get_sha1_hex(line, old_sha1) ||
 725                     get_sha1_hex(line + 41, new_sha1))
 726                         die("protocol error: expected old/new/ref, got '%s'",
 727                             line);
 728
 729                 refname = line + 82;
 730                 reflen = strlen(refname);
 731                 if (reflen + 82 < len) {
 732                         if (strstr(refname + reflen + 1, "report-status"))
 733                                 report_status = 1;
 734                         if (strstr(refname + reflen + 1, "side-band-64k"))
 735                                 use_sideband = LARGE_PACKET_MAX;
 736                 }
 737                 cmd = xcalloc(1, sizeof(struct command) + len - 80);
 738                 hashcpy(cmd->old_sha1, old_sha1);
 739                 hashcpy(cmd->new_sha1, new_sha1);
 740                 memcpy(cmd->ref_name, line + 82, len - 81);
 741                 *p = cmd;
 742                 p = &cmd->next;
 743         }
 744         return commands;
 745 }
 746
 747 static const char *parse_pack_header(struct pack_header *hdr)
 748 {
 749         switch (read_pack_header(0, hdr)) {
 750         case PH_ERROR_EOF:
 751                 return "eof before pack header was fully read";
 752
 753         case PH_ERROR_PACK_SIGNATURE:
 754                 return "protocol error (pack signature mismatch detected)";
 755
 756         case PH_ERROR_PROTOCOL:
 757                 return "protocol error (pack version unsupported)";
 758
 759         default:
 760                 return "unknown error in parse_pack_header";
 761
 762         case 0:
 763                 return NULL;
 764         }
 765 }
 766
 767 static const char *pack_lockfile;
 768
 769 static const char *unpack(void)
 770 {
 771         struct pack_header hdr;
 772         const char *hdr_err;
 773         char hdr_arg[38];
 774         int fsck_objects = (receive_fsck_objects >= 0
 775                             ? receive_fsck_objects
 776                             : transfer_fsck_objects >= 0
 777                             ? transfer_fsck_objects
 778                             : 0);
 779
 780         hdr_err = parse_pack_header(&hdr);
 781         if (hdr_err)
 782                 return hdr_err;
 783         snprintf(hdr_arg, sizeof(hdr_arg),
 784                         "--pack_header=%"PRIu32",%"PRIu32,
 785                         ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
 786
 787         if (ntohl(hdr.hdr_entries) < unpack_limit) {
 788                 int code, i = 0;
 789                 const char *unpacker[4];
 790                 unpacker[i++] = "unpack-objects";
 791                 if (fsck_objects)
 792                         unpacker[i++] = "--strict";
 793                 unpacker[i++] = hdr_arg;
 794                 unpacker[i++] = NULL;
 795                 code = run_command_v_opt(unpacker, RUN_GIT_CMD);
 796                 if (!code)
 797                         return NULL;
 798                 return "unpack-objects abnormal exit";
 799         } else {
 800                 const char *keeper[7];
 801                 int s, status, i = 0;
 802                 char keep_arg[256];
 803                 struct child_process ip;
 804
 805                 s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
 806                 if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 807                         strcpy(keep_arg + s, "localhost");
 808
 809                 keeper[i++] = "index-pack";
 810                 keeper[i++] = "--stdin";
 811                 if (fsck_objects)
 812                         keeper[i++] = "--strict";
 813                 keeper[i++] = "--fix-thin";
 814                 keeper[i++] = hdr_arg;
 815                 keeper[i++] = keep_arg;
 816                 keeper[i++] = NULL;
 817                 memset(&ip, 0, sizeof(ip));
 818                 ip.argv = keeper;
 819                 ip.out = -1;
 820                 ip.git_cmd = 1;
 821                 status = start_command(&ip);
 822                 if (status) {
 823                         return "index-pack fork failed";
 824                 }
 825                 pack_lockfile = index_pack_lockfile(ip.out);
 826                 close(ip.out);
 827                 status = finish_command(&ip);
 828                 if (!status) {
 829                         reprepare_packed_git();
 830                         return NULL;
 831                 }
 832                 return "index-pack abnormal exit";
 833         }
 834 }
 835
 836 static void report(struct command *commands, const char *unpack_status)
 837 {
 838         struct command *cmd;
 839         struct strbuf buf = STRBUF_INIT;
 840
 841         packet_buf_write(&buf, "unpack %s\n",
 842                          unpack_status ? unpack_status : "ok");
 843         for (cmd = commands; cmd; cmd = cmd->next) {
 844                 if (!cmd->error_string)
 845                         packet_buf_write(&buf, "ok %s\n",
 846                                          cmd->ref_name);
 847                 else
 848                         packet_buf_write(&buf, "ng %s %s\n",
 849                                          cmd->ref_name, cmd->error_string);
 850         }
 851         packet_buf_flush(&buf);
 852
 853         if (use_sideband)
 854                 send_sideband(1, 1, buf.buf, buf.len, use_sideband);
 855         else
 856                 safe_write(1, buf.buf, buf.len);
 857         strbuf_release(&buf);
 858 }
 859
 860 static int delete_only(struct command *commands)
 861 {
 862         struct command *cmd;
 863         for (cmd = commands; cmd; cmd = cmd->next) {
 864                 if (!is_null_sha1(cmd->new_sha1))
 865                         return 0;
 866         }
 867         return 1;
 868 }
 869
 870 static void add_one_alternate_sha1(const unsigned char sha1[20], void *unused)
 871 {
 872         add_extra_ref(".have", sha1, 0);
 873 }
 874
 875 static void collect_one_alternate_ref(const struct ref *ref, void *data)
 876 {
 877         struct sha1_array *sa = data;
 878         sha1_array_append(sa, ref->old_sha1);
 879 }
 880
 881 static void add_alternate_refs(void)
 882 {
 883         struct sha1_array sa = SHA1_ARRAY_INIT;
 884         for_each_alternate_ref(collect_one_alternate_ref, &sa);
 885         sha1_array_for_each_unique(&sa, add_one_alternate_sha1, NULL);
 886         sha1_array_clear(&sa);
 887 }
 888
 889 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 890 {
 891         int advertise_refs = 0;
 892         int stateless_rpc = 0;
 893         int i;
 894         char *dir = NULL;
 895         struct command *commands;
 896
 897         packet_trace_identity("receive-pack");
 898
 899         argv++;
 900         for (i = 1; i < argc; i++) {
 901                 const char *arg = *argv++;
 902
 903                 if (*arg == '-') {
 904                         if (!strcmp(arg, "--advertise-refs")) {
 905                                 advertise_refs = 1;
 906                                 continue;
 907                         }
 908                         if (!strcmp(arg, "--stateless-rpc")) {
 909                                 stateless_rpc = 1;
 910                                 continue;
 911                         }
 912
 913                         usage(receive_pack_usage);
 914                 }
 915                 if (dir)
 916                         usage(receive_pack_usage);
 917                 dir = xstrdup(arg);
 918         }
 919         if (!dir)
 920                 usage(receive_pack_usage);
 921
 922         setup_path();
 923
 924         if (!enter_repo(dir, 0))
 925                 die("'%s' does not appear to be a git repository", dir);
 926
 927         if (is_repository_shallow())
 928                 die("attempt to push into a shallow repository");
 929
 930         git_config(receive_pack_config, NULL);
 931
 932         if (0 <= transfer_unpack_limit)
 933                 unpack_limit = transfer_unpack_limit;
 934         else if (0 <= receive_unpack_limit)
 935                 unpack_limit = receive_unpack_limit;
 936
 937         if (advertise_refs || !stateless_rpc) {
 938                 add_alternate_refs();
 939                 write_head_info();
 940                 clear_extra_refs();
 941
 942                 /* EOF */
 943                 packet_flush(1);
 944         }
 945         if (advertise_refs)
 946                 return 0;
 947
 948         if ((commands = read_head_info()) != NULL) {
 949                 const char *unpack_status = NULL;
 950
 951                 if (!delete_only(commands))
 952                         unpack_status = unpack();
 953                 execute_commands(commands, unpack_status);
 954                 if (pack_lockfile)
 955                         unlink_or_warn(pack_lockfile);
 956                 if (report_status)
 957                         report(commands, unpack_status);
 958                 run_receive_hook(commands, post_receive_hook, 1);
 959                 run_update_post_hook(commands);
 960                 if (auto_gc) {
 961                         const char *argv_gc_auto[] = {
 962                                 "gc", "--auto", "--quiet", NULL,
 963                         };
 964                         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 965                 }
 966                 if (auto_update_server_info)
 967                         update_server_info(0);
 968         }
 969         if (use_sideband)
 970                 packet_flush(1);
 971         return 0;
 972 }