git.oblomov.eu Git - git/blob - 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 "connect.h"
  12 #include "transport.h"
  13 #include "string-list.h"
  14 #include "sha1-array.h"
  15 #include "connected.h"
  16 #include "argv-array.h"
  17 #include "version.h"
  18
  19 static const char receive_pack_usage[] = "git receive-pack <git-dir>";
  20
  21 enum deny_action {
  22         DENY_UNCONFIGURED,
  23         DENY_IGNORE,
  24         DENY_WARN,
  25         DENY_REFUSE
  26 };
  27
  28 static int deny_deletes;
  29 static int deny_non_fast_forwards;
  30 static enum deny_action deny_current_branch = DENY_UNCONFIGURED;
  31 static enum deny_action deny_delete_current = DENY_UNCONFIGURED;
  32 static int receive_fsck_objects = -1;
  33 static int transfer_fsck_objects = -1;
  34 static int receive_unpack_limit = -1;
  35 static int transfer_unpack_limit = -1;
  36 static int unpack_limit = 100;
  37 static int report_status;
  38 static int use_sideband;
  39 static int quiet;
  40 static int prefer_ofs_delta = 1;
  41 static int auto_update_server_info;
  42 static int auto_gc = 1;
  43 static int fix_thin = 1;
  44 static const char *head_name;
  45 static void *head_name_to_free;
  46 static int sent_capabilities;
  47 static int shallow_update;
  48 static const char *alt_shallow_file;
  49
  50 static enum deny_action parse_deny_action(const char *var, const char *value)
  51 {
  52         if (value) {
  53                 if (!strcasecmp(value, "ignore"))
  54                         return DENY_IGNORE;
  55                 if (!strcasecmp(value, "warn"))
  56                         return DENY_WARN;
  57                 if (!strcasecmp(value, "refuse"))
  58                         return DENY_REFUSE;
  59         }
  60         if (git_config_bool(var, value))
  61                 return DENY_REFUSE;
  62         return DENY_IGNORE;
  63 }
  64
  65 static int receive_pack_config(const char *var, const char *value, void *cb)
  66 {
  67         int status = parse_hide_refs_config(var, value, "receive");
  68
  69         if (status)
  70                 return status;
  71
  72         if (strcmp(var, "receive.denydeletes") == 0) {
  73                 deny_deletes = git_config_bool(var, value);
  74                 return 0;
  75         }
  76
  77         if (strcmp(var, "receive.denynonfastforwards") == 0) {
  78                 deny_non_fast_forwards = git_config_bool(var, value);
  79                 return 0;
  80         }
  81
  82         if (strcmp(var, "receive.unpacklimit") == 0) {
  83                 receive_unpack_limit = git_config_int(var, value);
  84                 return 0;
  85         }
  86
  87         if (strcmp(var, "transfer.unpacklimit") == 0) {
  88                 transfer_unpack_limit = git_config_int(var, value);
  89                 return 0;
  90         }
  91
  92         if (strcmp(var, "receive.fsckobjects") == 0) {
  93                 receive_fsck_objects = git_config_bool(var, value);
  94                 return 0;
  95         }
  96
  97         if (strcmp(var, "transfer.fsckobjects") == 0) {
  98                 transfer_fsck_objects = git_config_bool(var, value);
  99                 return 0;
 100         }
 101
 102         if (!strcmp(var, "receive.denycurrentbranch")) {
 103                 deny_current_branch = parse_deny_action(var, value);
 104                 return 0;
 105         }
 106
 107         if (strcmp(var, "receive.denydeletecurrent") == 0) {
 108                 deny_delete_current = parse_deny_action(var, value);
 109                 return 0;
 110         }
 111
 112         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 113                 prefer_ofs_delta = git_config_bool(var, value);
 114                 return 0;
 115         }
 116
 117         if (strcmp(var, "receive.updateserverinfo") == 0) {
 118                 auto_update_server_info = git_config_bool(var, value);
 119                 return 0;
 120         }
 121
 122         if (strcmp(var, "receive.autogc") == 0) {
 123                 auto_gc = git_config_bool(var, value);
 124                 return 0;
 125         }
 126
 127         if (strcmp(var, "receive.shallowupdate") == 0) {
 128                 shallow_update = git_config_bool(var, value);
 129                 return 0;
 130         }
 131
 132         return git_default_config(var, value, cb);
 133 }
 134
 135 static void show_ref(const char *path, const unsigned char *sha1)
 136 {
 137         if (ref_is_hidden(path))
 138                 return;
 139
 140         if (sent_capabilities)
 141                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
 142         else
 143                 packet_write(1, "%s %s%c%s%s agent=%s\n",
 144                              sha1_to_hex(sha1), path, 0,
 145                              " report-status delete-refs side-band-64k quiet",
 146                              prefer_ofs_delta ? " ofs-delta" : "",
 147                              git_user_agent_sanitized());
 148         sent_capabilities = 1;
 149 }
 150
 151 static int show_ref_cb(const char *path, const unsigned char *sha1, int flag, void *unused)
 152 {
 153         path = strip_namespace(path);
 154         /*
 155          * Advertise refs outside our current namespace as ".have"
 156          * refs, so that the client can use them to minimize data
 157          * transfer but will otherwise ignore them. This happens to
 158          * cover ".have" that are thrown in by add_one_alternate_ref()
 159          * to mark histories that are complete in our alternates as
 160          * well.
 161          */
 162         if (!path)
 163                 path = ".have";
 164         show_ref(path, sha1);
 165         return 0;
 166 }
 167
 168 static void show_one_alternate_sha1(const unsigned char sha1[20], void *unused)
 169 {
 170         show_ref(".have", sha1);
 171 }
 172
 173 static void collect_one_alternate_ref(const struct ref *ref, void *data)
 174 {
 175         struct sha1_array *sa = data;
 176         sha1_array_append(sa, ref->old_sha1);
 177 }
 178
 179 static void write_head_info(void)
 180 {
 181         struct sha1_array sa = SHA1_ARRAY_INIT;
 182         for_each_alternate_ref(collect_one_alternate_ref, &sa);
 183         sha1_array_for_each_unique(&sa, show_one_alternate_sha1, NULL);
 184         sha1_array_clear(&sa);
 185         for_each_ref(show_ref_cb, NULL);
 186         if (!sent_capabilities)
 187                 show_ref("capabilities^{}", null_sha1);
 188
 189         advertise_shallow_grafts(1);
 190
 191         /* EOF */
 192         packet_flush(1);
 193 }
 194
 195 struct command {
 196         struct command *next;
 197         const char *error_string;
 198         unsigned int skip_update:1,
 199                      did_not_exist:1;
 200         int index;
 201         unsigned char old_sha1[20];
 202         unsigned char new_sha1[20];
 203         char ref_name[FLEX_ARRAY]; /* more */
 204 };
 205
 206 static void rp_error(const char *err, ...) __attribute__((format (printf, 1, 2)));
 207 static void rp_warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
 208
 209 static void report_message(const char *prefix, const char *err, va_list params)
 210 {
 211         int sz = strlen(prefix);
 212         char msg[4096];
 213
 214         strncpy(msg, prefix, sz);
 215         sz += vsnprintf(msg + sz, sizeof(msg) - sz, err, params);
 216         if (sz > (sizeof(msg) - 1))
 217                 sz = sizeof(msg) - 1;
 218         msg[sz++] = '\n';
 219
 220         if (use_sideband)
 221                 send_sideband(1, 2, msg, sz, use_sideband);
 222         else
 223                 xwrite(2, msg, sz);
 224 }
 225
 226 static void rp_warning(const char *err, ...)
 227 {
 228         va_list params;
 229         va_start(params, err);
 230         report_message("warning: ", err, params);
 231         va_end(params);
 232 }
 233
 234 static void rp_error(const char *err, ...)
 235 {
 236         va_list params;
 237         va_start(params, err);
 238         report_message("error: ", err, params);
 239         va_end(params);
 240 }
 241
 242 static int copy_to_sideband(int in, int out, void *arg)
 243 {
 244         char data[128];
 245         while (1) {
 246                 ssize_t sz = xread(in, data, sizeof(data));
 247                 if (sz <= 0)
 248                         break;
 249                 send_sideband(1, 2, data, sz, use_sideband);
 250         }
 251         close(in);
 252         return 0;
 253 }
 254
 255 typedef int (*feed_fn)(void *, const char **, size_t *);
 256 static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state)
 257 {
 258         struct child_process proc;
 259         struct async muxer;
 260         const char *argv[2];
 261         int code;
 262
 263         argv[0] = find_hook(hook_name);
 264         if (!argv[0])
 265                 return 0;
 266
 267         argv[1] = NULL;
 268
 269         memset(&proc, 0, sizeof(proc));
 270         proc.argv = argv;
 271         proc.in = -1;
 272         proc.stdout_to_stderr = 1;
 273
 274         if (use_sideband) {
 275                 memset(&muxer, 0, sizeof(muxer));
 276                 muxer.proc = copy_to_sideband;
 277                 muxer.in = -1;
 278                 code = start_async(&muxer);
 279                 if (code)
 280                         return code;
 281                 proc.err = muxer.in;
 282         }
 283
 284         code = start_command(&proc);
 285         if (code) {
 286                 if (use_sideband)
 287                         finish_async(&muxer);
 288                 return code;
 289         }
 290
 291         while (1) {
 292                 const char *buf;
 293                 size_t n;
 294                 if (feed(feed_state, &buf, &n))
 295                         break;
 296                 if (write_in_full(proc.in, buf, n) != n)
 297                         break;
 298         }
 299         close(proc.in);
 300         if (use_sideband)
 301                 finish_async(&muxer);
 302         return finish_command(&proc);
 303 }
 304
 305 struct receive_hook_feed_state {
 306         struct command *cmd;
 307         int skip_broken;
 308         struct strbuf buf;
 309 };
 310
 311 static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
 312 {
 313         struct receive_hook_feed_state *state = state_;
 314         struct command *cmd = state->cmd;
 315
 316         while (cmd &&
 317                state->skip_broken && (cmd->error_string || cmd->did_not_exist))
 318                 cmd = cmd->next;
 319         if (!cmd)
 320                 return -1; /* EOF */
 321         strbuf_reset(&state->buf);
 322         strbuf_addf(&state->buf, "%s %s %s\n",
 323                     sha1_to_hex(cmd->old_sha1), sha1_to_hex(cmd->new_sha1),
 324                     cmd->ref_name);
 325         state->cmd = cmd->next;
 326         if (bufp) {
 327                 *bufp = state->buf.buf;
 328                 *sizep = state->buf.len;
 329         }
 330         return 0;
 331 }
 332
 333 static int run_receive_hook(struct command *commands, const char *hook_name,
 334                             int skip_broken)
 335 {
 336         struct receive_hook_feed_state state;
 337         int status;
 338
 339         strbuf_init(&state.buf, 0);
 340         state.cmd = commands;
 341         state.skip_broken = skip_broken;
 342         if (feed_receive_hook(&state, NULL, NULL))
 343                 return 0;
 344         state.cmd = commands;
 345         status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
 346         strbuf_release(&state.buf);
 347         return status;
 348 }
 349
 350 static int run_update_hook(struct command *cmd)
 351 {
 352         const char *argv[5];
 353         struct child_process proc;
 354         int code;
 355
 356         argv[0] = find_hook("update");
 357         if (!argv[0])
 358                 return 0;
 359
 360         argv[1] = cmd->ref_name;
 361         argv[2] = sha1_to_hex(cmd->old_sha1);
 362         argv[3] = sha1_to_hex(cmd->new_sha1);
 363         argv[4] = NULL;
 364
 365         memset(&proc, 0, sizeof(proc));
 366         proc.no_stdin = 1;
 367         proc.stdout_to_stderr = 1;
 368         proc.err = use_sideband ? -1 : 0;
 369         proc.argv = argv;
 370
 371         code = start_command(&proc);
 372         if (code)
 373                 return code;
 374         if (use_sideband)
 375                 copy_to_sideband(proc.err, -1, NULL);
 376         return finish_command(&proc);
 377 }
 378
 379 static int is_ref_checked_out(const char *ref)
 380 {
 381         if (is_bare_repository())
 382                 return 0;
 383
 384         if (!head_name)
 385                 return 0;
 386         return !strcmp(head_name, ref);
 387 }
 388
 389 static char *refuse_unconfigured_deny_msg[] = {
 390         "By default, updating the current branch in a non-bare repository",
 391         "is denied, because it will make the index and work tree inconsistent",
 392         "with what you pushed, and will require 'git reset --hard' to match",
 393         "the work tree to HEAD.",
 394         "",
 395         "You can set 'receive.denyCurrentBranch' configuration variable to",
 396         "'ignore' or 'warn' in the remote repository to allow pushing into",
 397         "its current branch; however, this is not recommended unless you",
 398         "arranged to update its work tree to match what you pushed in some",
 399         "other way.",
 400         "",
 401         "To squelch this message and still keep the default behaviour, set",
 402         "'receive.denyCurrentBranch' configuration variable to 'refuse'."
 403 };
 404
 405 static void refuse_unconfigured_deny(void)
 406 {
 407         int i;
 408         for (i = 0; i < ARRAY_SIZE(refuse_unconfigured_deny_msg); i++)
 409                 rp_error("%s", refuse_unconfigured_deny_msg[i]);
 410 }
 411
 412 static char *refuse_unconfigured_deny_delete_current_msg[] = {
 413         "By default, deleting the current branch is denied, because the next",
 414         "'git clone' won't result in any file checked out, causing confusion.",
 415         "",
 416         "You can set 'receive.denyDeleteCurrent' configuration variable to",
 417         "'warn' or 'ignore' in the remote repository to allow deleting the",
 418         "current branch, with or without a warning message.",
 419         "",
 420         "To squelch this message, you can set it to 'refuse'."
 421 };
 422
 423 static void refuse_unconfigured_deny_delete_current(void)
 424 {
 425         int i;
 426         for (i = 0;
 427              i < ARRAY_SIZE(refuse_unconfigured_deny_delete_current_msg);
 428              i++)
 429                 rp_error("%s", refuse_unconfigured_deny_delete_current_msg[i]);
 430 }
 431
 432 static int command_singleton_iterator(void *cb_data, unsigned char sha1[20]);
 433 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 434 {
 435         static struct lock_file shallow_lock;
 436         struct sha1_array extra = SHA1_ARRAY_INIT;
 437         const char *alt_file;
 438         uint32_t mask = 1 << (cmd->index % 32);
 439         int i;
 440
 441         trace_printf_key("GIT_TRACE_SHALLOW",
 442                          "shallow: update_shallow_ref %s\n", cmd->ref_name);
 443         for (i = 0; i < si->shallow->nr; i++)
 444                 if (si->used_shallow[i] &&
 445                     (si->used_shallow[i][cmd->index / 32] & mask) &&
 446                     !delayed_reachability_test(si, i))
 447                         sha1_array_append(&extra, si->shallow->sha1[i]);
 448
 449         setup_alternate_shallow(&shallow_lock, &alt_file, &extra);
 450         if (check_shallow_connected(command_singleton_iterator,
 451                                     0, cmd, alt_file)) {
 452                 rollback_lock_file(&shallow_lock);
 453                 sha1_array_clear(&extra);
 454                 return -1;
 455         }
 456
 457         commit_lock_file(&shallow_lock);
 458
 459         /*
 460          * Make sure setup_alternate_shallow() for the next ref does
 461          * not lose these new roots..
 462          */
 463         for (i = 0; i < extra.nr; i++)
 464                 register_shallow(extra.sha1[i]);
 465
 466         si->shallow_ref[cmd->index] = 0;
 467         sha1_array_clear(&extra);
 468         return 0;
 469 }
 470
 471 static const char *update(struct command *cmd, struct shallow_info *si)
 472 {
 473         const char *name = cmd->ref_name;
 474         struct strbuf namespaced_name_buf = STRBUF_INIT;
 475         const char *namespaced_name;
 476         unsigned char *old_sha1 = cmd->old_sha1;
 477         unsigned char *new_sha1 = cmd->new_sha1;
 478         struct ref_lock *lock;
 479
 480         /* only refs/... are allowed */
 481         if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
 482                 rp_error("refusing to create funny ref '%s' remotely", name);
 483                 return "funny refname";
 484         }
 485
 486         strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
 487         namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
 488
 489         if (is_ref_checked_out(namespaced_name)) {
 490                 switch (deny_current_branch) {
 491                 case DENY_IGNORE:
 492                         break;
 493                 case DENY_WARN:
 494                         rp_warning("updating the current branch");
 495                         break;
 496                 case DENY_REFUSE:
 497                 case DENY_UNCONFIGURED:
 498                         rp_error("refusing to update checked out branch: %s", name);
 499                         if (deny_current_branch == DENY_UNCONFIGURED)
 500                                 refuse_unconfigured_deny();
 501                         return "branch is currently checked out";
 502                 }
 503         }
 504
 505         if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
 506                 error("unpack should have generated %s, "
 507                       "but I can't find it!", sha1_to_hex(new_sha1));
 508                 return "bad pack";
 509         }
 510
 511         if (!is_null_sha1(old_sha1) && is_null_sha1(new_sha1)) {
 512                 if (deny_deletes && starts_with(name, "refs/heads/")) {
 513                         rp_error("denying ref deletion for %s", name);
 514                         return "deletion prohibited";
 515                 }
 516
 517                 if (!strcmp(namespaced_name, head_name)) {
 518                         switch (deny_delete_current) {
 519                         case DENY_IGNORE:
 520                                 break;
 521                         case DENY_WARN:
 522                                 rp_warning("deleting the current branch");
 523                                 break;
 524                         case DENY_REFUSE:
 525                         case DENY_UNCONFIGURED:
 526                                 if (deny_delete_current == DENY_UNCONFIGURED)
 527                                         refuse_unconfigured_deny_delete_current();
 528                                 rp_error("refusing to delete the current branch: %s", name);
 529                                 return "deletion of the current branch prohibited";
 530                         }
 531                 }
 532         }
 533
 534         if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
 535             !is_null_sha1(old_sha1) &&
 536             starts_with(name, "refs/heads/")) {
 537                 struct object *old_object, *new_object;
 538                 struct commit *old_commit, *new_commit;
 539
 540                 old_object = parse_object(old_sha1);
 541                 new_object = parse_object(new_sha1);
 542
 543                 if (!old_object || !new_object ||
 544                     old_object->type != OBJ_COMMIT ||
 545                     new_object->type != OBJ_COMMIT) {
 546                         error("bad sha1 objects for %s", name);
 547                         return "bad ref";
 548                 }
 549                 old_commit = (struct commit *)old_object;
 550                 new_commit = (struct commit *)new_object;
 551                 if (!in_merge_bases(old_commit, new_commit)) {
 552                         rp_error("denying non-fast-forward %s"
 553                                  " (you should pull first)", name);
 554                         return "non-fast-forward";
 555                 }
 556         }
 557         if (run_update_hook(cmd)) {
 558                 rp_error("hook declined to update %s", name);
 559                 return "hook declined";
 560         }
 561
 562         if (is_null_sha1(new_sha1)) {
 563                 if (!parse_object(old_sha1)) {
 564                         old_sha1 = NULL;
 565                         if (ref_exists(name)) {
 566                                 rp_warning("Allowing deletion of corrupt ref.");
 567                         } else {
 568                                 rp_warning("Deleting a non-existent ref.");
 569                                 cmd->did_not_exist = 1;
 570                         }
 571                 }
 572                 if (delete_ref(namespaced_name, old_sha1, 0)) {
 573                         rp_error("failed to delete %s", name);
 574                         return "failed to delete";
 575                 }
 576                 return NULL; /* good */
 577         }
 578         else {
 579                 if (shallow_update && si->shallow_ref[cmd->index] &&
 580                     update_shallow_ref(cmd, si))
 581                         return "shallow error";
 582
 583                 lock = lock_any_ref_for_update(namespaced_name, old_sha1,
 584                                                0, NULL);
 585                 if (!lock) {
 586                         rp_error("failed to lock %s", name);
 587                         return "failed to lock";
 588                 }
 589                 if (write_ref_sha1(lock, new_sha1, "push")) {
 590                         return "failed to write"; /* error() already called */
 591                 }
 592                 return NULL; /* good */
 593         }
 594 }
 595
 596 static void run_update_post_hook(struct command *commands)
 597 {
 598         struct command *cmd;
 599         int argc;
 600         const char **argv;
 601         struct child_process proc;
 602         char *hook;
 603
 604         hook = find_hook("post-update");
 605         for (argc = 0, cmd = commands; cmd; cmd = cmd->next) {
 606                 if (cmd->error_string || cmd->did_not_exist)
 607                         continue;
 608                 argc++;
 609         }
 610         if (!argc || !hook)
 611                 return;
 612
 613         argv = xmalloc(sizeof(*argv) * (2 + argc));
 614         argv[0] = hook;
 615
 616         for (argc = 1, cmd = commands; cmd; cmd = cmd->next) {
 617                 char *p;
 618                 if (cmd->error_string || cmd->did_not_exist)
 619                         continue;
 620                 p = xmalloc(strlen(cmd->ref_name) + 1);
 621                 strcpy(p, cmd->ref_name);
 622                 argv[argc] = p;
 623                 argc++;
 624         }
 625         argv[argc] = NULL;
 626
 627         memset(&proc, 0, sizeof(proc));
 628         proc.no_stdin = 1;
 629         proc.stdout_to_stderr = 1;
 630         proc.err = use_sideband ? -1 : 0;
 631         proc.argv = argv;
 632
 633         if (!start_command(&proc)) {
 634                 if (use_sideband)
 635                         copy_to_sideband(proc.err, -1, NULL);
 636                 finish_command(&proc);
 637         }
 638 }
 639
 640 static void check_aliased_update(struct command *cmd, struct string_list *list)
 641 {
 642         struct strbuf buf = STRBUF_INIT;
 643         const char *dst_name;
 644         struct string_list_item *item;
 645         struct command *dst_cmd;
 646         unsigned char sha1[20];
 647         char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41];
 648         int flag;
 649
 650         strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
 651         dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
 652         strbuf_release(&buf);
 653
 654         if (!(flag & REF_ISSYMREF))
 655                 return;
 656
 657         dst_name = strip_namespace(dst_name);
 658         if (!dst_name) {
 659                 rp_error("refusing update to broken symref '%s'", cmd->ref_name);
 660                 cmd->skip_update = 1;
 661                 cmd->error_string = "broken symref";
 662                 return;
 663         }
 664
 665         if ((item = string_list_lookup(list, dst_name)) == NULL)
 666                 return;
 667
 668         cmd->skip_update = 1;
 669
 670         dst_cmd = (struct command *) item->util;
 671
 672         if (!hashcmp(cmd->old_sha1, dst_cmd->old_sha1) &&
 673             !hashcmp(cmd->new_sha1, dst_cmd->new_sha1))
 674                 return;
 675
 676         dst_cmd->skip_update = 1;
 677
 678         strcpy(cmd_oldh, find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV));
 679         strcpy(cmd_newh, find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV));
 680         strcpy(dst_oldh, find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV));
 681         strcpy(dst_newh, find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV));
 682         rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
 683                  " its target '%s' (%s..%s)",
 684                  cmd->ref_name, cmd_oldh, cmd_newh,
 685                  dst_cmd->ref_name, dst_oldh, dst_newh);
 686
 687         cmd->error_string = dst_cmd->error_string =
 688                 "inconsistent aliased update";
 689 }
 690
 691 static void check_aliased_updates(struct command *commands)
 692 {
 693         struct command *cmd;
 694         struct string_list ref_list = STRING_LIST_INIT_NODUP;
 695
 696         for (cmd = commands; cmd; cmd = cmd->next) {
 697                 struct string_list_item *item =
 698                         string_list_append(&ref_list, cmd->ref_name);
 699                 item->util = (void *)cmd;
 700         }
 701         sort_string_list(&ref_list);
 702
 703         for (cmd = commands; cmd; cmd = cmd->next) {
 704                 if (!cmd->error_string)
 705                         check_aliased_update(cmd, &ref_list);
 706         }
 707
 708         string_list_clear(&ref_list, 0);
 709 }
 710
 711 static int command_singleton_iterator(void *cb_data, unsigned char sha1[20])
 712 {
 713         struct command **cmd_list = cb_data;
 714         struct command *cmd = *cmd_list;
 715
 716         if (!cmd || is_null_sha1(cmd->new_sha1))
 717                 return -1; /* end of list */
 718         *cmd_list = NULL; /* this returns only one */
 719         hashcpy(sha1, cmd->new_sha1);
 720         return 0;
 721 }
 722
 723 static void set_connectivity_errors(struct command *commands,
 724                                     struct shallow_info *si)
 725 {
 726         struct command *cmd;
 727
 728         for (cmd = commands; cmd; cmd = cmd->next) {
 729                 struct command *singleton = cmd;
 730                 if (shallow_update && si->shallow_ref[cmd->index])
 731                         /* to be checked in update_shallow_ref() */
 732                         continue;
 733                 if (!check_everything_connected(command_singleton_iterator,
 734                                                 0, &singleton))
 735                         continue;
 736                 cmd->error_string = "missing necessary objects";
 737         }
 738 }
 739
 740 struct iterate_data {
 741         struct command *cmds;
 742         struct shallow_info *si;
 743 };
 744
 745 static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
 746 {
 747         struct iterate_data *data = cb_data;
 748         struct command **cmd_list = &data->cmds;
 749         struct command *cmd = *cmd_list;
 750
 751         for (; cmd; cmd = cmd->next) {
 752                 if (shallow_update && data->si->shallow_ref[cmd->index])
 753                         /* to be checked in update_shallow_ref() */
 754                         continue;
 755                 if (!is_null_sha1(cmd->new_sha1) && !cmd->skip_update) {
 756                         hashcpy(sha1, cmd->new_sha1);
 757                         *cmd_list = cmd->next;
 758                         return 0;
 759                 }
 760         }
 761         *cmd_list = NULL;
 762         return -1; /* end of list */
 763 }
 764
 765 static void reject_updates_to_hidden(struct command *commands)
 766 {
 767         struct command *cmd;
 768
 769         for (cmd = commands; cmd; cmd = cmd->next) {
 770                 if (cmd->error_string || !ref_is_hidden(cmd->ref_name))
 771                         continue;
 772                 if (is_null_sha1(cmd->new_sha1))
 773                         cmd->error_string = "deny deleting a hidden ref";
 774                 else
 775                         cmd->error_string = "deny updating a hidden ref";
 776         }
 777 }
 778
 779 static void execute_commands(struct command *commands,
 780                              const char *unpacker_error,
 781                              struct shallow_info *si)
 782 {
 783         int checked_connectivity;
 784         struct command *cmd;
 785         unsigned char sha1[20];
 786         struct iterate_data data;
 787
 788         if (unpacker_error) {
 789                 for (cmd = commands; cmd; cmd = cmd->next)
 790                         cmd->error_string = "unpacker error";
 791                 return;
 792         }
 793
 794         data.cmds = commands;
 795         data.si = si;
 796         if (check_everything_connected(iterate_receive_command_list, 0, &data))
 797                 set_connectivity_errors(commands, si);
 798
 799         reject_updates_to_hidden(commands);
 800
 801         if (run_receive_hook(commands, "pre-receive", 0)) {
 802                 for (cmd = commands; cmd; cmd = cmd->next) {
 803                         if (!cmd->error_string)
 804                                 cmd->error_string = "pre-receive hook declined";
 805                 }
 806                 return;
 807         }
 808
 809         check_aliased_updates(commands);
 810
 811         free(head_name_to_free);
 812         head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
 813
 814         checked_connectivity = 1;
 815         for (cmd = commands; cmd; cmd = cmd->next) {
 816                 if (cmd->error_string)
 817                         continue;
 818
 819                 if (cmd->skip_update)
 820                         continue;
 821
 822                 cmd->error_string = update(cmd, si);
 823                 if (shallow_update && !cmd->error_string &&
 824                     si->shallow_ref[cmd->index]) {
 825                         error("BUG: connectivity check has not been run on ref %s",
 826                               cmd->ref_name);
 827                         checked_connectivity = 0;
 828                 }
 829         }
 830
 831         if (shallow_update) {
 832                 if (!checked_connectivity)
 833                         error("BUG: run 'git fsck' for safety.\n"
 834                               "If there are errors, try to remove "
 835                               "the reported refs above");
 836                 if (alt_shallow_file && *alt_shallow_file)
 837                         unlink(alt_shallow_file);
 838         }
 839 }
 840
 841 static struct command *read_head_info(struct sha1_array *shallow)
 842 {
 843         struct command *commands = NULL;
 844         struct command **p = &commands;
 845         for (;;) {
 846                 char *line;
 847                 unsigned char old_sha1[20], new_sha1[20];
 848                 struct command *cmd;
 849                 char *refname;
 850                 int len, reflen;
 851
 852                 line = packet_read_line(0, &len);
 853                 if (!line)
 854                         break;
 855
 856                 if (len == 48 && starts_with(line, "shallow ")) {
 857                         if (get_sha1_hex(line + 8, old_sha1))
 858                                 die("protocol error: expected shallow sha, got '%s'", line + 8);
 859                         sha1_array_append(shallow, old_sha1);
 860                         continue;
 861                 }
 862
 863                 if (len < 83 ||
 864                     line[40] != ' ' ||
 865                     line[81] != ' ' ||
 866                     get_sha1_hex(line, old_sha1) ||
 867                     get_sha1_hex(line + 41, new_sha1))
 868                         die("protocol error: expected old/new/ref, got '%s'",
 869                             line);
 870
 871                 refname = line + 82;
 872                 reflen = strlen(refname);
 873                 if (reflen + 82 < len) {
 874                         const char *feature_list = refname + reflen + 1;
 875                         if (parse_feature_request(feature_list, "report-status"))
 876                                 report_status = 1;
 877                         if (parse_feature_request(feature_list, "side-band-64k"))
 878                                 use_sideband = LARGE_PACKET_MAX;
 879                         if (parse_feature_request(feature_list, "quiet"))
 880                                 quiet = 1;
 881                 }
 882                 cmd = xcalloc(1, sizeof(struct command) + len - 80);
 883                 hashcpy(cmd->old_sha1, old_sha1);
 884                 hashcpy(cmd->new_sha1, new_sha1);
 885                 memcpy(cmd->ref_name, line + 82, len - 81);
 886                 *p = cmd;
 887                 p = &cmd->next;
 888         }
 889         return commands;
 890 }
 891
 892 static const char *parse_pack_header(struct pack_header *hdr)
 893 {
 894         switch (read_pack_header(0, hdr)) {
 895         case PH_ERROR_EOF:
 896                 return "eof before pack header was fully read";
 897
 898         case PH_ERROR_PACK_SIGNATURE:
 899                 return "protocol error (pack signature mismatch detected)";
 900
 901         case PH_ERROR_PROTOCOL:
 902                 return "protocol error (pack version unsupported)";
 903
 904         default:
 905                 return "unknown error in parse_pack_header";
 906
 907         case 0:
 908                 return NULL;
 909         }
 910 }
 911
 912 static const char *pack_lockfile;
 913
 914 static const char *unpack(int err_fd, struct shallow_info *si)
 915 {
 916         struct pack_header hdr;
 917         struct argv_array av = ARGV_ARRAY_INIT;
 918         const char *hdr_err;
 919         int status;
 920         char hdr_arg[38];
 921         struct child_process child;
 922         int fsck_objects = (receive_fsck_objects >= 0
 923                             ? receive_fsck_objects
 924                             : transfer_fsck_objects >= 0
 925                             ? transfer_fsck_objects
 926                             : 0);
 927
 928         hdr_err = parse_pack_header(&hdr);
 929         if (hdr_err) {
 930                 if (err_fd > 0)
 931                         close(err_fd);
 932                 return hdr_err;
 933         }
 934         snprintf(hdr_arg, sizeof(hdr_arg),
 935                         "--pack_header=%"PRIu32",%"PRIu32,
 936                         ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
 937
 938         if (si->nr_ours || si->nr_theirs) {
 939                 alt_shallow_file = setup_temporary_shallow(si->shallow);
 940                 argv_array_pushl(&av, "--shallow-file", alt_shallow_file, NULL);
 941         }
 942
 943         memset(&child, 0, sizeof(child));
 944         if (ntohl(hdr.hdr_entries) < unpack_limit) {
 945                 argv_array_pushl(&av, "unpack-objects", hdr_arg, NULL);
 946                 if (quiet)
 947                         argv_array_push(&av, "-q");
 948                 if (fsck_objects)
 949                         argv_array_push(&av, "--strict");
 950                 child.argv = av.argv;
 951                 child.no_stdout = 1;
 952                 child.err = err_fd;
 953                 child.git_cmd = 1;
 954                 status = run_command(&child);
 955                 if (status)
 956                         return "unpack-objects abnormal exit";
 957         } else {
 958                 int s;
 959                 char keep_arg[256];
 960
 961                 s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
 962                 if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 963                         strcpy(keep_arg + s, "localhost");
 964
 965                 argv_array_pushl(&av, "index-pack",
 966                                  "--stdin", hdr_arg, keep_arg, NULL);
 967                 if (fsck_objects)
 968                         argv_array_push(&av, "--strict");
 969                 if (fix_thin)
 970                         argv_array_push(&av, "--fix-thin");
 971                 child.argv = av.argv;
 972                 child.out = -1;
 973                 child.err = err_fd;
 974                 child.git_cmd = 1;
 975                 status = start_command(&child);
 976                 if (status)
 977                         return "index-pack fork failed";
 978                 pack_lockfile = index_pack_lockfile(child.out);
 979                 close(child.out);
 980                 status = finish_command(&child);
 981                 if (status)
 982                         return "index-pack abnormal exit";
 983                 reprepare_packed_git();
 984         }
 985         return NULL;
 986 }
 987
 988 static const char *unpack_with_sideband(struct shallow_info *si)
 989 {
 990         struct async muxer;
 991         const char *ret;
 992
 993         if (!use_sideband)
 994                 return unpack(0, si);
 995
 996         memset(&muxer, 0, sizeof(muxer));
 997         muxer.proc = copy_to_sideband;
 998         muxer.in = -1;
 999         if (start_async(&muxer))
1000                 return NULL;
1001
1002         ret = unpack(muxer.in, si);
1003
1004         finish_async(&muxer);
1005         return ret;
1006 }
1007
1008 static void prepare_shallow_update(struct command *commands,
1009                                    struct shallow_info *si)
1010 {
1011         int i, j, k, bitmap_size = (si->ref->nr + 31) / 32;
1012
1013         si->used_shallow = xmalloc(sizeof(*si->used_shallow) *
1014                                    si->shallow->nr);
1015         assign_shallow_commits_to_refs(si, si->used_shallow, NULL);
1016
1017         si->need_reachability_test =
1018                 xcalloc(si->shallow->nr, sizeof(*si->need_reachability_test));
1019         si->reachable =
1020                 xcalloc(si->shallow->nr, sizeof(*si->reachable));
1021         si->shallow_ref = xcalloc(si->ref->nr, sizeof(*si->shallow_ref));
1022
1023         for (i = 0; i < si->nr_ours; i++)
1024                 si->need_reachability_test[si->ours[i]] = 1;
1025
1026         for (i = 0; i < si->shallow->nr; i++) {
1027                 if (!si->used_shallow[i])
1028                         continue;
1029                 for (j = 0; j < bitmap_size; j++) {
1030                         if (!si->used_shallow[i][j])
1031                                 continue;
1032                         si->need_reachability_test[i]++;
1033                         for (k = 0; k < 32; k++)
1034                                 if (si->used_shallow[i][j] & (1 << k))
1035                                         si->shallow_ref[j * 32 + k]++;
1036                 }
1037
1038                 /*
1039                  * true for those associated with some refs and belong
1040                  * in "ours" list aka "step 7 not done yet"
1041                  */
1042                 si->need_reachability_test[i] =
1043                         si->need_reachability_test[i] > 1;
1044         }
1045
1046         /*
1047          * keep hooks happy by forcing a temporary shallow file via
1048          * env variable because we can't add --shallow-file to every
1049          * command. check_everything_connected() will be done with
1050          * true .git/shallow though.
1051          */
1052         setenv(GIT_SHALLOW_FILE_ENVIRONMENT, alt_shallow_file, 1);
1053 }
1054
1055 static void update_shallow_info(struct command *commands,
1056                                 struct shallow_info *si,
1057                                 struct sha1_array *ref)
1058 {
1059         struct command *cmd;
1060         int *ref_status;
1061         remove_nonexistent_theirs_shallow(si);
1062         if (!si->nr_ours && !si->nr_theirs) {
1063                 shallow_update = 0;
1064                 return;
1065         }
1066
1067         for (cmd = commands; cmd; cmd = cmd->next) {
1068                 if (is_null_sha1(cmd->new_sha1))
1069                         continue;
1070                 sha1_array_append(ref, cmd->new_sha1);
1071                 cmd->index = ref->nr - 1;
1072         }
1073         si->ref = ref;
1074
1075         if (shallow_update) {
1076                 prepare_shallow_update(commands, si);
1077                 return;
1078         }
1079
1080         ref_status = xmalloc(sizeof(*ref_status) * ref->nr);
1081         assign_shallow_commits_to_refs(si, NULL, ref_status);
1082         for (cmd = commands; cmd; cmd = cmd->next) {
1083                 if (is_null_sha1(cmd->new_sha1))
1084                         continue;
1085                 if (ref_status[cmd->index]) {
1086                         cmd->error_string = "shallow update not allowed";
1087                         cmd->skip_update = 1;
1088                 }
1089         }
1090         if (alt_shallow_file && *alt_shallow_file) {
1091                 unlink(alt_shallow_file);
1092                 alt_shallow_file = NULL;
1093         }
1094         free(ref_status);
1095 }
1096
1097 static void report(struct command *commands, const char *unpack_status)
1098 {
1099         struct command *cmd;
1100         struct strbuf buf = STRBUF_INIT;
1101
1102         packet_buf_write(&buf, "unpack %s\n",
1103                          unpack_status ? unpack_status : "ok");
1104         for (cmd = commands; cmd; cmd = cmd->next) {
1105                 if (!cmd->error_string)
1106                         packet_buf_write(&buf, "ok %s\n",
1107                                          cmd->ref_name);
1108                 else
1109                         packet_buf_write(&buf, "ng %s %s\n",
1110                                          cmd->ref_name, cmd->error_string);
1111         }
1112         packet_buf_flush(&buf);
1113
1114         if (use_sideband)
1115                 send_sideband(1, 1, buf.buf, buf.len, use_sideband);
1116         else
1117                 write_or_die(1, buf.buf, buf.len);
1118         strbuf_release(&buf);
1119 }
1120
1121 static int delete_only(struct command *commands)
1122 {
1123         struct command *cmd;
1124         for (cmd = commands; cmd; cmd = cmd->next) {
1125                 if (!is_null_sha1(cmd->new_sha1))
1126                         return 0;
1127         }
1128         return 1;
1129 }
1130
1131 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
1132 {
1133         int advertise_refs = 0;
1134         int stateless_rpc = 0;
1135         int i;
1136         char *dir = NULL;
1137         struct command *commands;
1138         struct sha1_array shallow = SHA1_ARRAY_INIT;
1139         struct sha1_array ref = SHA1_ARRAY_INIT;
1140         struct shallow_info si;
1141
1142         packet_trace_identity("receive-pack");
1143
1144         argv++;
1145         for (i = 1; i < argc; i++) {
1146                 const char *arg = *argv++;
1147
1148                 if (*arg == '-') {
1149                         if (!strcmp(arg, "--quiet")) {
1150                                 quiet = 1;
1151                                 continue;
1152                         }
1153
1154                         if (!strcmp(arg, "--advertise-refs")) {
1155                                 advertise_refs = 1;
1156                                 continue;
1157                         }
1158                         if (!strcmp(arg, "--stateless-rpc")) {
1159                                 stateless_rpc = 1;
1160                                 continue;
1161                         }
1162                         if (!strcmp(arg, "--reject-thin-pack-for-testing")) {
1163                                 fix_thin = 0;
1164                                 continue;
1165                         }
1166
1167                         usage(receive_pack_usage);
1168                 }
1169                 if (dir)
1170                         usage(receive_pack_usage);
1171                 dir = xstrdup(arg);
1172         }
1173         if (!dir)
1174                 usage(receive_pack_usage);
1175
1176         setup_path();
1177
1178         if (!enter_repo(dir, 0))
1179                 die("'%s' does not appear to be a git repository", dir);
1180
1181         git_config(receive_pack_config, NULL);
1182
1183         if (0 <= transfer_unpack_limit)
1184                 unpack_limit = transfer_unpack_limit;
1185         else if (0 <= receive_unpack_limit)
1186                 unpack_limit = receive_unpack_limit;
1187
1188         if (advertise_refs || !stateless_rpc) {
1189                 write_head_info();
1190         }
1191         if (advertise_refs)
1192                 return 0;
1193
1194         if ((commands = read_head_info(&shallow)) != NULL) {
1195                 const char *unpack_status = NULL;
1196
1197                 prepare_shallow_info(&si, &shallow);
1198                 if (!si.nr_ours && !si.nr_theirs)
1199                         shallow_update = 0;
1200                 if (!delete_only(commands)) {
1201                         unpack_status = unpack_with_sideband(&si);
1202                         update_shallow_info(commands, &si, &ref);
1203                 }
1204                 execute_commands(commands, unpack_status, &si);
1205                 if (pack_lockfile)
1206                         unlink_or_warn(pack_lockfile);
1207                 if (report_status)
1208                         report(commands, unpack_status);
1209                 run_receive_hook(commands, "post-receive", 1);
1210                 run_update_post_hook(commands);
1211                 if (auto_gc) {
1212                         const char *argv_gc_auto[] = {
1213                                 "gc", "--auto", "--quiet", NULL,
1214                         };
1215                         int opt = RUN_GIT_CMD | RUN_COMMAND_STDOUT_TO_STDERR;
1216                         run_command_v_opt(argv_gc_auto, opt);
1217                 }
1218                 if (auto_update_server_info)
1219                         update_server_info(0);
1220                 clear_shallow_info(&si);
1221         }
1222         if (use_sideband)
1223                 packet_flush(1);
1224         sha1_array_clear(&shallow);
1225         sha1_array_clear(&ref);
1226         return 0;
1227 }