builtin/receive-pack.c

   1 #include "builtin.h"
   2 #include "lockfile.h"
   3 #include "pack.h"
   4 #include "refs.h"
   5 #include "pkt-line.h"
   6 #include "sideband.h"
   7 #include "run-command.h"
   8 #include "exec_cmd.h"
   9 #include "commit.h"
  10 #include "object.h"
  11 #include "remote.h"
  12 #include "connect.h"
  13 #include "transport.h"
  14 #include "string-list.h"
  15 #include "sha1-array.h"
  16 #include "connected.h"
  17 #include "argv-array.h"
  18 #include "version.h"
  19 #include "tag.h"
  20 #include "gpg-interface.h"
  21 #include "sigchain.h"
  22 #include "fsck.h"
  23 #include "tmp-objdir.h"
  24 #include "oidset.h"
  25
  26 static const char * const receive_pack_usage[] = {
  27         N_("git receive-pack <git-dir>"),
  28         NULL
  29 };
  30
  31 enum deny_action {
  32         DENY_UNCONFIGURED,
  33         DENY_IGNORE,
  34         DENY_WARN,
  35         DENY_REFUSE,
  36         DENY_UPDATE_INSTEAD
  37 };
  38
  39 static int deny_deletes;
  40 static int deny_non_fast_forwards;
  41 static enum deny_action deny_current_branch = DENY_UNCONFIGURED;
  42 static enum deny_action deny_delete_current = DENY_UNCONFIGURED;
  43 static int receive_fsck_objects = -1;
  44 static int transfer_fsck_objects = -1;
  45 static struct strbuf fsck_msg_types = STRBUF_INIT;
  46 static int receive_unpack_limit = -1;
  47 static int transfer_unpack_limit = -1;
  48 static int advertise_atomic_push = 1;
  49 static int advertise_push_options;
  50 static int unpack_limit = 100;
  51 static off_t max_input_size;
  52 static int report_status;
  53 static int use_sideband;
  54 static int use_atomic;
  55 static int use_push_options;
  56 static int quiet;
  57 static int prefer_ofs_delta = 1;
  58 static int auto_update_server_info;
  59 static int auto_gc = 1;
  60 static int reject_thin;
  61 static int stateless_rpc;
  62 static const char *service_dir;
  63 static const char *head_name;
  64 static void *head_name_to_free;
  65 static int sent_capabilities;
  66 static int shallow_update;
  67 static const char *alt_shallow_file;
  68 static struct strbuf push_cert = STRBUF_INIT;
  69 static unsigned char push_cert_sha1[20];
  70 static struct signature_check sigcheck;
  71 static const char *push_cert_nonce;
  72 static const char *cert_nonce_seed;
  73
  74 static const char *NONCE_UNSOLICITED = "UNSOLICITED";
  75 static const char *NONCE_BAD = "BAD";
  76 static const char *NONCE_MISSING = "MISSING";
  77 static const char *NONCE_OK = "OK";
  78 static const char *NONCE_SLOP = "SLOP";
  79 static const char *nonce_status;
  80 static long nonce_stamp_slop;
  81 static timestamp_t nonce_stamp_slop_limit;
  82 static struct ref_transaction *transaction;
  83
  84 static enum {
  85         KEEPALIVE_NEVER = 0,
  86         KEEPALIVE_AFTER_NUL,
  87         KEEPALIVE_ALWAYS
  88 } use_keepalive;
  89 static int keepalive_in_sec = 5;
  90
  91 static struct tmp_objdir *tmp_objdir;
  92
  93 static enum deny_action parse_deny_action(const char *var, const char *value)
  94 {
  95         if (value) {
  96                 if (!strcasecmp(value, "ignore"))
  97                         return DENY_IGNORE;
  98                 if (!strcasecmp(value, "warn"))
  99                         return DENY_WARN;
 100                 if (!strcasecmp(value, "refuse"))
 101                         return DENY_REFUSE;
 102                 if (!strcasecmp(value, "updateinstead"))
 103                         return DENY_UPDATE_INSTEAD;
 104         }
 105         if (git_config_bool(var, value))
 106                 return DENY_REFUSE;
 107         return DENY_IGNORE;
 108 }
 109
 110 static int receive_pack_config(const char *var, const char *value, void *cb)
 111 {
 112         int status = parse_hide_refs_config(var, value, "receive");
 113
 114         if (status)
 115                 return status;
 116
 117         if (strcmp(var, "receive.denydeletes") == 0) {
 118                 deny_deletes = git_config_bool(var, value);
 119                 return 0;
 120         }
 121
 122         if (strcmp(var, "receive.denynonfastforwards") == 0) {
 123                 deny_non_fast_forwards = git_config_bool(var, value);
 124                 return 0;
 125         }
 126
 127         if (strcmp(var, "receive.unpacklimit") == 0) {
 128                 receive_unpack_limit = git_config_int(var, value);
 129                 return 0;
 130         }
 131
 132         if (strcmp(var, "transfer.unpacklimit") == 0) {
 133                 transfer_unpack_limit = git_config_int(var, value);
 134                 return 0;
 135         }
 136
 137         if (strcmp(var, "receive.fsck.skiplist") == 0) {
 138                 const char *path;
 139
 140                 if (git_config_pathname(&path, var, value))
 141                         return 1;
 142                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
 143                         fsck_msg_types.len ? ',' : '=', path);
 144                 free((char *)path);
 145                 return 0;
 146         }
 147
 148         if (skip_prefix(var, "receive.fsck.", &var)) {
 149                 if (is_valid_msg_type(var, value))
 150                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
 151                                 fsck_msg_types.len ? ',' : '=', var, value);
 152                 else
 153                         warning("Skipping unknown msg id '%s'", var);
 154                 return 0;
 155         }
 156
 157         if (strcmp(var, "receive.fsckobjects") == 0) {
 158                 receive_fsck_objects = git_config_bool(var, value);
 159                 return 0;
 160         }
 161
 162         if (strcmp(var, "transfer.fsckobjects") == 0) {
 163                 transfer_fsck_objects = git_config_bool(var, value);
 164                 return 0;
 165         }
 166
 167         if (!strcmp(var, "receive.denycurrentbranch")) {
 168                 deny_current_branch = parse_deny_action(var, value);
 169                 return 0;
 170         }
 171
 172         if (strcmp(var, "receive.denydeletecurrent") == 0) {
 173                 deny_delete_current = parse_deny_action(var, value);
 174                 return 0;
 175         }
 176
 177         if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 178                 prefer_ofs_delta = git_config_bool(var, value);
 179                 return 0;
 180         }
 181
 182         if (strcmp(var, "receive.updateserverinfo") == 0) {
 183                 auto_update_server_info = git_config_bool(var, value);
 184                 return 0;
 185         }
 186
 187         if (strcmp(var, "receive.autogc") == 0) {
 188                 auto_gc = git_config_bool(var, value);
 189                 return 0;
 190         }
 191
 192         if (strcmp(var, "receive.shallowupdate") == 0) {
 193                 shallow_update = git_config_bool(var, value);
 194                 return 0;
 195         }
 196
 197         if (strcmp(var, "receive.certnonceseed") == 0)
 198                 return git_config_string(&cert_nonce_seed, var, value);
 199
 200         if (strcmp(var, "receive.certnonceslop") == 0) {
 201                 nonce_stamp_slop_limit = git_config_ulong(var, value);
 202                 return 0;
 203         }
 204
 205         if (strcmp(var, "receive.advertiseatomic") == 0) {
 206                 advertise_atomic_push = git_config_bool(var, value);
 207                 return 0;
 208         }
 209
 210         if (strcmp(var, "receive.advertisepushoptions") == 0) {
 211                 advertise_push_options = git_config_bool(var, value);
 212                 return 0;
 213         }
 214
 215         if (strcmp(var, "receive.keepalive") == 0) {
 216                 keepalive_in_sec = git_config_int(var, value);
 217                 return 0;
 218         }
 219
 220         if (strcmp(var, "receive.maxinputsize") == 0) {
 221                 max_input_size = git_config_int64(var, value);
 222                 return 0;
 223         }
 224
 225         return git_default_config(var, value, cb);
 226 }
 227
 228 static void show_ref(const char *path, const struct object_id *oid)
 229 {
 230         if (sent_capabilities) {
 231                 packet_write_fmt(1, "%s %s\n", oid_to_hex(oid), path);
 232         } else {
 233                 struct strbuf cap = STRBUF_INIT;
 234
 235                 strbuf_addstr(&cap,
 236                               "report-status delete-refs side-band-64k quiet");
 237                 if (advertise_atomic_push)
 238                         strbuf_addstr(&cap, " atomic");
 239                 if (prefer_ofs_delta)
 240                         strbuf_addstr(&cap, " ofs-delta");
 241                 if (push_cert_nonce)
 242                         strbuf_addf(&cap, " push-cert=%s", push_cert_nonce);
 243                 if (advertise_push_options)
 244                         strbuf_addstr(&cap, " push-options");
 245                 strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
 246                 packet_write_fmt(1, "%s %s%c%s\n",
 247                              oid_to_hex(oid), path, 0, cap.buf);
 248                 strbuf_release(&cap);
 249                 sent_capabilities = 1;
 250         }
 251 }
 252
 253 static int show_ref_cb(const char *path_full, const struct object_id *oid,
 254                        int flag, void *data)
 255 {
 256         struct oidset *seen = data;
 257         const char *path = strip_namespace(path_full);
 258
 259         if (ref_is_hidden(path, path_full))
 260                 return 0;
 261
 262         /*
 263          * Advertise refs outside our current namespace as ".have"
 264          * refs, so that the client can use them to minimize data
 265          * transfer but will otherwise ignore them.
 266          */
 267         if (!path) {
 268                 if (oidset_insert(seen, oid))
 269                         return 0;
 270                 path = ".have";
 271         } else {
 272                 oidset_insert(seen, oid);
 273         }
 274         show_ref(path, oid);
 275         return 0;
 276 }
 277
 278 static void show_one_alternate_ref(const char *refname,
 279                                    const struct object_id *oid,
 280                                    void *data)
 281 {
 282         struct oidset *seen = data;
 283
 284         if (oidset_insert(seen, oid))
 285                 return;
 286
 287         show_ref(".have", oid);
 288 }
 289
 290 static void write_head_info(void)
 291 {
 292         static struct oidset seen = OIDSET_INIT;
 293
 294         for_each_ref(show_ref_cb, &seen);
 295         for_each_alternate_ref(show_one_alternate_ref, &seen);
 296         oidset_clear(&seen);
 297         if (!sent_capabilities)
 298                 show_ref("capabilities^{}", &null_oid);
 299
 300         advertise_shallow_grafts(1);
 301
 302         /* EOF */
 303         packet_flush(1);
 304 }
 305
 306 struct command {
 307         struct command *next;
 308         const char *error_string;
 309         unsigned int skip_update:1,
 310                      did_not_exist:1;
 311         int index;
 312         struct object_id old_oid;
 313         struct object_id new_oid;
 314         char ref_name[FLEX_ARRAY]; /* more */
 315 };
 316
 317 static void rp_error(const char *err, ...) __attribute__((format (printf, 1, 2)));
 318 static void rp_warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
 319
 320 static void report_message(const char *prefix, const char *err, va_list params)
 321 {
 322         int sz;
 323         char msg[4096];
 324
 325         sz = xsnprintf(msg, sizeof(msg), "%s", prefix);
 326         sz += vsnprintf(msg + sz, sizeof(msg) - sz, err, params);
 327         if (sz > (sizeof(msg) - 1))
 328                 sz = sizeof(msg) - 1;
 329         msg[sz++] = '\n';
 330
 331         if (use_sideband)
 332                 send_sideband(1, 2, msg, sz, use_sideband);
 333         else
 334                 xwrite(2, msg, sz);
 335 }
 336
 337 static void rp_warning(const char *err, ...)
 338 {
 339         va_list params;
 340         va_start(params, err);
 341         report_message("warning: ", err, params);
 342         va_end(params);
 343 }
 344
 345 static void rp_error(const char *err, ...)
 346 {
 347         va_list params;
 348         va_start(params, err);
 349         report_message("error: ", err, params);
 350         va_end(params);
 351 }
 352
 353 static int copy_to_sideband(int in, int out, void *arg)
 354 {
 355         char data[128];
 356         int keepalive_active = 0;
 357
 358         if (keepalive_in_sec <= 0)
 359                 use_keepalive = KEEPALIVE_NEVER;
 360         if (use_keepalive == KEEPALIVE_ALWAYS)
 361                 keepalive_active = 1;
 362
 363         while (1) {
 364                 ssize_t sz;
 365
 366                 if (keepalive_active) {
 367                         struct pollfd pfd;
 368                         int ret;
 369
 370                         pfd.fd = in;
 371                         pfd.events = POLLIN;
 372                         ret = poll(&pfd, 1, 1000 * keepalive_in_sec);
 373
 374                         if (ret < 0) {
 375                                 if (errno == EINTR)
 376                                         continue;
 377                                 else
 378                                         break;
 379                         } else if (ret == 0) {
 380                                 /* no data; send a keepalive packet */
 381                                 static const char buf[] = "0005\1";
 382                                 write_or_die(1, buf, sizeof(buf) - 1);
 383                                 continue;
 384                         } /* else there is actual data to read */
 385                 }
 386
 387                 sz = xread(in, data, sizeof(data));
 388                 if (sz <= 0)
 389                         break;
 390
 391                 if (use_keepalive == KEEPALIVE_AFTER_NUL && !keepalive_active) {
 392                         const char *p = memchr(data, '\0', sz);
 393                         if (p) {
 394                                 /*
 395                                  * The NUL tells us to start sending keepalives. Make
 396                                  * sure we send any other data we read along
 397                                  * with it.
 398                                  */
 399                                 keepalive_active = 1;
 400                                 send_sideband(1, 2, data, p - data, use_sideband);
 401                                 send_sideband(1, 2, p + 1, sz - (p - data + 1), use_sideband);
 402                                 continue;
 403                         }
 404                 }
 405
 406                 /*
 407                  * Either we're not looking for a NUL signal, or we didn't see
 408                  * it yet; just pass along the data.
 409                  */
 410                 send_sideband(1, 2, data, sz, use_sideband);
 411         }
 412         close(in);
 413         return 0;
 414 }
 415
 416 #define HMAC_BLOCK_SIZE 64
 417
 418 static void hmac_sha1(unsigned char *out,
 419                       const char *key_in, size_t key_len,
 420                       const char *text, size_t text_len)
 421 {
 422         unsigned char key[HMAC_BLOCK_SIZE];
 423         unsigned char k_ipad[HMAC_BLOCK_SIZE];
 424         unsigned char k_opad[HMAC_BLOCK_SIZE];
 425         int i;
 426         git_SHA_CTX ctx;
 427
 428         /* RFC 2104 2. (1) */
 429         memset(key, '\0', HMAC_BLOCK_SIZE);
 430         if (HMAC_BLOCK_SIZE < key_len) {
 431                 git_SHA1_Init(&ctx);
 432                 git_SHA1_Update(&ctx, key_in, key_len);
 433                 git_SHA1_Final(key, &ctx);
 434         } else {
 435                 memcpy(key, key_in, key_len);
 436         }
 437
 438         /* RFC 2104 2. (2) & (5) */
 439         for (i = 0; i < sizeof(key); i++) {
 440                 k_ipad[i] = key[i] ^ 0x36;
 441                 k_opad[i] = key[i] ^ 0x5c;
 442         }
 443
 444         /* RFC 2104 2. (3) & (4) */
 445         git_SHA1_Init(&ctx);
 446         git_SHA1_Update(&ctx, k_ipad, sizeof(k_ipad));
 447         git_SHA1_Update(&ctx, text, text_len);
 448         git_SHA1_Final(out, &ctx);
 449
 450         /* RFC 2104 2. (6) & (7) */
 451         git_SHA1_Init(&ctx);
 452         git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));
 453         git_SHA1_Update(&ctx, out, 20);
 454         git_SHA1_Final(out, &ctx);
 455 }
 456
 457 static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
 458 {
 459         struct strbuf buf = STRBUF_INIT;
 460         unsigned char sha1[20];
 461
 462         strbuf_addf(&buf, "%s:%"PRItime, path, stamp);
 463         hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;
 464         strbuf_release(&buf);
 465
 466         /* RFC 2104 5. HMAC-SHA1-80 */
 467         strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1));
 468         return strbuf_detach(&buf, NULL);
 469 }
 470
 471 /*
 472  * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
 473  * after dropping "_commit" from its name and possibly moving it out
 474  * of commit.c
 475  */
 476 static char *find_header(const char *msg, size_t len, const char *key,
 477                          const char **next_line)
 478 {
 479         int key_len = strlen(key);
 480         const char *line = msg;
 481
 482         while (line && line < msg + len) {
 483                 const char *eol = strchrnul(line, '\n');
 484
 485                 if ((msg + len <= eol) || line == eol)
 486                         return NULL;
 487                 if (line + key_len < eol &&
 488                     !memcmp(line, key, key_len) && line[key_len] == ' ') {
 489                         int offset = key_len + 1;
 490                         if (next_line)
 491                                 *next_line = *eol ? eol + 1 : eol;
 492                         return xmemdupz(line + offset, (eol - line) - offset);
 493                 }
 494                 line = *eol ? eol + 1 : NULL;
 495         }
 496         return NULL;
 497 }
 498
 499 static const char *check_nonce(const char *buf, size_t len)
 500 {
 501         char *nonce = find_header(buf, len, "nonce", NULL);
 502         timestamp_t stamp, ostamp;
 503         char *bohmac, *expect = NULL;
 504         const char *retval = NONCE_BAD;
 505
 506         if (!nonce) {
 507                 retval = NONCE_MISSING;
 508                 goto leave;
 509         } else if (!push_cert_nonce) {
 510                 retval = NONCE_UNSOLICITED;
 511                 goto leave;
 512         } else if (!strcmp(push_cert_nonce, nonce)) {
 513                 retval = NONCE_OK;
 514                 goto leave;
 515         }
 516
 517         if (!stateless_rpc) {
 518                 /* returned nonce MUST match what we gave out earlier */
 519                 retval = NONCE_BAD;
 520                 goto leave;
 521         }
 522
 523         /*
 524          * In stateless mode, we may be receiving a nonce issued by
 525          * another instance of the server that serving the same
 526          * repository, and the timestamps may not match, but the
 527          * nonce-seed and dir should match, so we can recompute and
 528          * report the time slop.
 529          *
 530          * In addition, when a nonce issued by another instance has
 531          * timestamp within receive.certnonceslop seconds, we pretend
 532          * as if we issued that nonce when reporting to the hook.
 533          */
 534
 535         /* nonce is concat(<seconds-since-epoch>, "-", <hmac>) */
 536         if (*nonce <= '0' || '9' < *nonce) {
 537                 retval = NONCE_BAD;
 538                 goto leave;
 539         }
 540         stamp = parse_timestamp(nonce, &bohmac, 10);
 541         if (bohmac == nonce || bohmac[0] != '-') {
 542                 retval = NONCE_BAD;
 543                 goto leave;
 544         }
 545
 546         expect = prepare_push_cert_nonce(service_dir, stamp);
 547         if (strcmp(expect, nonce)) {
 548                 /* Not what we would have signed earlier */
 549                 retval = NONCE_BAD;
 550                 goto leave;
 551         }
 552
 553         /*
 554          * By how many seconds is this nonce stale?  Negative value
 555          * would mean it was issued by another server with its clock
 556          * skewed in the future.
 557          */
 558         ostamp = parse_timestamp(push_cert_nonce, NULL, 10);
 559         nonce_stamp_slop = (long)ostamp - (long)stamp;
 560
 561         if (nonce_stamp_slop_limit &&
 562             labs(nonce_stamp_slop) <= nonce_stamp_slop_limit) {
 563                 /*
 564                  * Pretend as if the received nonce (which passes the
 565                  * HMAC check, so it is not a forged by third-party)
 566                  * is what we issued.
 567                  */
 568                 free((void *)push_cert_nonce);
 569                 push_cert_nonce = xstrdup(nonce);
 570                 retval = NONCE_OK;
 571         } else {
 572                 retval = NONCE_SLOP;
 573         }
 574
 575 leave:
 576         free(nonce);
 577         free(expect);
 578         return retval;
 579 }
 580
 581 /*
 582  * Return 1 if there is no push_cert or if the push options in push_cert are
 583  * the same as those in the argument; 0 otherwise.
 584  */
 585 static int check_cert_push_options(const struct string_list *push_options)
 586 {
 587         const char *buf = push_cert.buf;
 588         int len = push_cert.len;
 589
 590         char *option;
 591         const char *next_line;
 592         int options_seen = 0;
 593
 594         int retval = 1;
 595
 596         if (!len)
 597                 return 1;
 598
 599         while ((option = find_header(buf, len, "push-option", &next_line))) {
 600                 len -= (next_line - buf);
 601                 buf = next_line;
 602                 options_seen++;
 603                 if (options_seen > push_options->nr
 604                     || strcmp(option,
 605                               push_options->items[options_seen - 1].string)) {
 606                         retval = 0;
 607                         goto leave;
 608                 }
 609                 free(option);
 610         }
 611
 612         if (options_seen != push_options->nr)
 613                 retval = 0;
 614
 615 leave:
 616         free(option);
 617         return retval;
 618 }
 619
 620 static void prepare_push_cert_sha1(struct child_process *proc)
 621 {
 622         static int already_done;
 623
 624         if (!push_cert.len)
 625                 return;
 626
 627         if (!already_done) {
 628                 struct strbuf gpg_output = STRBUF_INIT;
 629                 struct strbuf gpg_status = STRBUF_INIT;
 630                 int bogs /* beginning_of_gpg_sig */;
 631
 632                 already_done = 1;
 633                 if (write_sha1_file(push_cert.buf, push_cert.len, "blob", push_cert_sha1))
 634                         hashclr(push_cert_sha1);
 635
 636                 memset(&sigcheck, '\0', sizeof(sigcheck));
 637                 sigcheck.result = 'N';
 638
 639                 bogs = parse_signature(push_cert.buf, push_cert.len);
 640                 if (verify_signed_buffer(push_cert.buf, bogs,
 641                                          push_cert.buf + bogs, push_cert.len - bogs,
 642                                          &gpg_output, &gpg_status) < 0) {
 643                         ; /* error running gpg */
 644                 } else {
 645                         sigcheck.payload = push_cert.buf;
 646                         sigcheck.gpg_output = gpg_output.buf;
 647                         sigcheck.gpg_status = gpg_status.buf;
 648                         parse_gpg_output(&sigcheck);
 649                 }
 650
 651                 strbuf_release(&gpg_output);
 652                 strbuf_release(&gpg_status);
 653                 nonce_status = check_nonce(push_cert.buf, bogs);
 654         }
 655         if (!is_null_sha1(push_cert_sha1)) {
 656                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT=%s",
 657                                  sha1_to_hex(push_cert_sha1));
 658                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_SIGNER=%s",
 659                                  sigcheck.signer ? sigcheck.signer : "");
 660                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_KEY=%s",
 661                                  sigcheck.key ? sigcheck.key : "");
 662                 argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_STATUS=%c",
 663                                  sigcheck.result);
 664                 if (push_cert_nonce) {
 665                         argv_array_pushf(&proc->env_array,
 666                                          "GIT_PUSH_CERT_NONCE=%s",
 667                                          push_cert_nonce);
 668                         argv_array_pushf(&proc->env_array,
 669                                          "GIT_PUSH_CERT_NONCE_STATUS=%s",
 670                                          nonce_status);
 671                         if (nonce_status == NONCE_SLOP)
 672                                 argv_array_pushf(&proc->env_array,
 673                                                  "GIT_PUSH_CERT_NONCE_SLOP=%ld",
 674                                                  nonce_stamp_slop);
 675                 }
 676         }
 677 }
 678
 679 struct receive_hook_feed_state {
 680         struct command *cmd;
 681         int skip_broken;
 682         struct strbuf buf;
 683         const struct string_list *push_options;
 684 };
 685
 686 typedef int (*feed_fn)(void *, const char **, size_t *);
 687 static int run_and_feed_hook(const char *hook_name, feed_fn feed,
 688                              struct receive_hook_feed_state *feed_state)
 689 {
 690         struct child_process proc = CHILD_PROCESS_INIT;
 691         struct async muxer;
 692         const char *argv[2];
 693         int code;
 694
 695         argv[0] = find_hook(hook_name);
 696         if (!argv[0])
 697                 return 0;
 698
 699         argv[1] = NULL;
 700
 701         proc.argv = argv;
 702         proc.in = -1;
 703         proc.stdout_to_stderr = 1;
 704         if (feed_state->push_options) {
 705                 int i;
 706                 for (i = 0; i < feed_state->push_options->nr; i++)
 707                         argv_array_pushf(&proc.env_array,
 708                                 "GIT_PUSH_OPTION_%d=%s", i,
 709                                 feed_state->push_options->items[i].string);
 710                 argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT=%d",
 711                                  feed_state->push_options->nr);
 712         } else
 713                 argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT");
 714
 715         if (tmp_objdir)
 716                 argv_array_pushv(&proc.env_array, tmp_objdir_env(tmp_objdir));
 717
 718         if (use_sideband) {
 719                 memset(&muxer, 0, sizeof(muxer));
 720                 muxer.proc = copy_to_sideband;
 721                 muxer.in = -1;
 722                 code = start_async(&muxer);
 723                 if (code)
 724                         return code;
 725                 proc.err = muxer.in;
 726         }
 727
 728         prepare_push_cert_sha1(&proc);
 729
 730         code = start_command(&proc);
 731         if (code) {
 732                 if (use_sideband)
 733                         finish_async(&muxer);
 734                 return code;
 735         }
 736
 737         sigchain_push(SIGPIPE, SIG_IGN);
 738
 739         while (1) {
 740                 const char *buf;
 741                 size_t n;
 742                 if (feed(feed_state, &buf, &n))
 743                         break;
 744                 if (write_in_full(proc.in, buf, n) != n)
 745                         break;
 746         }
 747         close(proc.in);
 748         if (use_sideband)
 749                 finish_async(&muxer);
 750
 751         sigchain_pop(SIGPIPE);
 752
 753         return finish_command(&proc);
 754 }
 755
 756 static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
 757 {
 758         struct receive_hook_feed_state *state = state_;
 759         struct command *cmd = state->cmd;
 760
 761         while (cmd &&
 762                state->skip_broken && (cmd->error_string || cmd->did_not_exist))
 763                 cmd = cmd->next;
 764         if (!cmd)
 765                 return -1; /* EOF */
 766         strbuf_reset(&state->buf);
 767         strbuf_addf(&state->buf, "%s %s %s\n",
 768                     oid_to_hex(&cmd->old_oid), oid_to_hex(&cmd->new_oid),
 769                     cmd->ref_name);
 770         state->cmd = cmd->next;
 771         if (bufp) {
 772                 *bufp = state->buf.buf;
 773                 *sizep = state->buf.len;
 774         }
 775         return 0;
 776 }
 777
 778 static int run_receive_hook(struct command *commands,
 779                             const char *hook_name,
 780                             int skip_broken,
 781                             const struct string_list *push_options)
 782 {
 783         struct receive_hook_feed_state state;
 784         int status;
 785
 786         strbuf_init(&state.buf, 0);
 787         state.cmd = commands;
 788         state.skip_broken = skip_broken;
 789         if (feed_receive_hook(&state, NULL, NULL))
 790                 return 0;
 791         state.cmd = commands;
 792         state.push_options = push_options;
 793         status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
 794         strbuf_release(&state.buf);
 795         return status;
 796 }
 797
 798 static int run_update_hook(struct command *cmd)
 799 {
 800         const char *argv[5];
 801         struct child_process proc = CHILD_PROCESS_INIT;
 802         int code;
 803
 804         argv[0] = find_hook("update");
 805         if (!argv[0])
 806                 return 0;
 807
 808         argv[1] = cmd->ref_name;
 809         argv[2] = oid_to_hex(&cmd->old_oid);
 810         argv[3] = oid_to_hex(&cmd->new_oid);
 811         argv[4] = NULL;
 812
 813         proc.no_stdin = 1;
 814         proc.stdout_to_stderr = 1;
 815         proc.err = use_sideband ? -1 : 0;
 816         proc.argv = argv;
 817
 818         code = start_command(&proc);
 819         if (code)
 820                 return code;
 821         if (use_sideband)
 822                 copy_to_sideband(proc.err, -1, NULL);
 823         return finish_command(&proc);
 824 }
 825
 826 static int is_ref_checked_out(const char *ref)
 827 {
 828         if (is_bare_repository())
 829                 return 0;
 830
 831         if (!head_name)
 832                 return 0;
 833         return !strcmp(head_name, ref);
 834 }
 835
 836 static char *refuse_unconfigured_deny_msg =
 837         N_("By default, updating the current branch in a non-bare repository\n"
 838            "is denied, because it will make the index and work tree inconsistent\n"
 839            "with what you pushed, and will require 'git reset --hard' to match\n"
 840            "the work tree to HEAD.\n"
 841            "\n"
 842            "You can set the 'receive.denyCurrentBranch' configuration variable\n"
 843            "to 'ignore' or 'warn' in the remote repository to allow pushing into\n"
 844            "its current branch; however, this is not recommended unless you\n"
 845            "arranged to update its work tree to match what you pushed in some\n"
 846            "other way.\n"
 847            "\n"
 848            "To squelch this message and still keep the default behaviour, set\n"
 849            "'receive.denyCurrentBranch' configuration variable to 'refuse'.");
 850
 851 static void refuse_unconfigured_deny(void)
 852 {
 853         rp_error("%s", _(refuse_unconfigured_deny_msg));
 854 }
 855
 856 static char *refuse_unconfigured_deny_delete_current_msg =
 857         N_("By default, deleting the current branch is denied, because the next\n"
 858            "'git clone' won't result in any file checked out, causing confusion.\n"
 859            "\n"
 860            "You can set 'receive.denyDeleteCurrent' configuration variable to\n"
 861            "'warn' or 'ignore' in the remote repository to allow deleting the\n"
 862            "current branch, with or without a warning message.\n"
 863            "\n"
 864            "To squelch this message, you can set it to 'refuse'.");
 865
 866 static void refuse_unconfigured_deny_delete_current(void)
 867 {
 868         rp_error("%s", _(refuse_unconfigured_deny_delete_current_msg));
 869 }
 870
 871 static int command_singleton_iterator(void *cb_data, unsigned char sha1[20]);
 872 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 873 {
 874         static struct lock_file shallow_lock;
 875         struct oid_array extra = OID_ARRAY_INIT;
 876         struct check_connected_options opt = CHECK_CONNECTED_INIT;
 877         uint32_t mask = 1 << (cmd->index % 32);
 878         int i;
 879
 880         trace_printf_key(&trace_shallow,
 881                          "shallow: update_shallow_ref %s\n", cmd->ref_name);
 882         for (i = 0; i < si->shallow->nr; i++)
 883                 if (si->used_shallow[i] &&
 884                     (si->used_shallow[i][cmd->index / 32] & mask) &&
 885                     !delayed_reachability_test(si, i))
 886                         oid_array_append(&extra, &si->shallow->oid[i]);
 887
 888         opt.env = tmp_objdir_env(tmp_objdir);
 889         setup_alternate_shallow(&shallow_lock, &opt.shallow_file, &extra);
 890         if (check_connected(command_singleton_iterator, cmd, &opt)) {
 891                 rollback_lock_file(&shallow_lock);
 892                 oid_array_clear(&extra);
 893                 return -1;
 894         }
 895
 896         commit_lock_file(&shallow_lock);
 897
 898         /*
 899          * Make sure setup_alternate_shallow() for the next ref does
 900          * not lose these new roots..
 901          */
 902         for (i = 0; i < extra.nr; i++)
 903                 register_shallow(extra.oid[i].hash);
 904
 905         si->shallow_ref[cmd->index] = 0;
 906         oid_array_clear(&extra);
 907         return 0;
 908 }
 909
 910 /*
 911  * NEEDSWORK: we should consolidate various implementions of "are we
 912  * on an unborn branch?" test into one, and make the unified one more
 913  * robust. !get_sha1() based check used here and elsewhere would not
 914  * allow us to tell an unborn branch from corrupt ref, for example.
 915  * For the purpose of fixing "deploy-to-update does not work when
 916  * pushing into an empty repository" issue, this should suffice for
 917  * now.
 918  */
 919 static int head_has_history(void)
 920 {
 921         unsigned char sha1[20];
 922
 923         return !get_sha1("HEAD", sha1);
 924 }
 925
 926 static const char *push_to_deploy(unsigned char *sha1,
 927                                   struct argv_array *env,
 928                                   const char *work_tree)
 929 {
 930         const char *update_refresh[] = {
 931                 "update-index", "-q", "--ignore-submodules", "--refresh", NULL
 932         };
 933         const char *diff_files[] = {
 934                 "diff-files", "--quiet", "--ignore-submodules", "--", NULL
 935         };
 936         const char *diff_index[] = {
 937                 "diff-index", "--quiet", "--cached", "--ignore-submodules",
 938                 NULL, "--", NULL
 939         };
 940         const char *read_tree[] = {
 941                 "read-tree", "-u", "-m", NULL, NULL
 942         };
 943         struct child_process child = CHILD_PROCESS_INIT;
 944
 945         child.argv = update_refresh;
 946         child.env = env->argv;
 947         child.dir = work_tree;
 948         child.no_stdin = 1;
 949         child.stdout_to_stderr = 1;
 950         child.git_cmd = 1;
 951         if (run_command(&child))
 952                 return "Up-to-date check failed";
 953
 954         /* run_command() does not clean up completely; reinitialize */
 955         child_process_init(&child);
 956         child.argv = diff_files;
 957         child.env = env->argv;
 958         child.dir = work_tree;
 959         child.no_stdin = 1;
 960         child.stdout_to_stderr = 1;
 961         child.git_cmd = 1;
 962         if (run_command(&child))
 963                 return "Working directory has unstaged changes";
 964
 965         /* diff-index with either HEAD or an empty tree */
 966         diff_index[4] = head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX;
 967
 968         child_process_init(&child);
 969         child.argv = diff_index;
 970         child.env = env->argv;
 971         child.no_stdin = 1;
 972         child.no_stdout = 1;
 973         child.stdout_to_stderr = 0;
 974         child.git_cmd = 1;
 975         if (run_command(&child))
 976                 return "Working directory has staged changes";
 977
 978         read_tree[3] = sha1_to_hex(sha1);
 979         child_process_init(&child);
 980         child.argv = read_tree;
 981         child.env = env->argv;
 982         child.dir = work_tree;
 983         child.no_stdin = 1;
 984         child.no_stdout = 1;
 985         child.stdout_to_stderr = 0;
 986         child.git_cmd = 1;
 987         if (run_command(&child))
 988                 return "Could not update working tree to new HEAD";
 989
 990         return NULL;
 991 }
 992
 993 static const char *push_to_checkout_hook = "push-to-checkout";
 994
 995 static const char *push_to_checkout(unsigned char *sha1,
 996                                     struct argv_array *env,
 997                                     const char *work_tree)
 998 {
 999         argv_array_pushf(env, "GIT_WORK_TREE=%s", absolute_path(work_tree));
1000         if (run_hook_le(env->argv, push_to_checkout_hook,
1001                         sha1_to_hex(sha1), NULL))
1002                 return "push-to-checkout hook declined";
1003         else
1004                 return NULL;
1005 }
1006
1007 static const char *update_worktree(unsigned char *sha1)
1008 {
1009         const char *retval;
1010         const char *work_tree = git_work_tree_cfg ? git_work_tree_cfg : "..";
1011         struct argv_array env = ARGV_ARRAY_INIT;
1012
1013         if (is_bare_repository())
1014                 return "denyCurrentBranch = updateInstead needs a worktree";
1015
1016         argv_array_pushf(&env, "GIT_DIR=%s", absolute_path(get_git_dir()));
1017
1018         if (!find_hook(push_to_checkout_hook))
1019                 retval = push_to_deploy(sha1, &env, work_tree);
1020         else
1021                 retval = push_to_checkout(sha1, &env, work_tree);
1022
1023         argv_array_clear(&env);
1024         return retval;
1025 }
1026
1027 static const char *update(struct command *cmd, struct shallow_info *si)
1028 {
1029         const char *name = cmd->ref_name;
1030         struct strbuf namespaced_name_buf = STRBUF_INIT;
1031         const char *namespaced_name, *ret;
1032         struct object_id *old_oid = &cmd->old_oid;
1033         struct object_id *new_oid = &cmd->new_oid;
1034
1035         /* only refs/... are allowed */
1036         if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
1037                 rp_error("refusing to create funny ref '%s' remotely", name);
1038                 return "funny refname";
1039         }
1040
1041         strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
1042         namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
1043
1044         if (is_ref_checked_out(namespaced_name)) {
1045                 switch (deny_current_branch) {
1046                 case DENY_IGNORE:
1047                         break;
1048                 case DENY_WARN:
1049                         rp_warning("updating the current branch");
1050                         break;
1051                 case DENY_REFUSE:
1052                 case DENY_UNCONFIGURED:
1053                         rp_error("refusing to update checked out branch: %s", name);
1054                         if (deny_current_branch == DENY_UNCONFIGURED)
1055                                 refuse_unconfigured_deny();
1056                         return "branch is currently checked out";
1057                 case DENY_UPDATE_INSTEAD:
1058                         ret = update_worktree(new_oid->hash);
1059                         if (ret)
1060                                 return ret;
1061                         break;
1062                 }
1063         }
1064
1065         if (!is_null_oid(new_oid) && !has_object_file(new_oid)) {
1066                 error("unpack should have generated %s, "
1067                       "but I can't find it!", oid_to_hex(new_oid));
1068                 return "bad pack";
1069         }
1070
1071         if (!is_null_oid(old_oid) && is_null_oid(new_oid)) {
1072                 if (deny_deletes && starts_with(name, "refs/heads/")) {
1073                         rp_error("denying ref deletion for %s", name);
1074                         return "deletion prohibited";
1075                 }
1076
1077                 if (head_name && !strcmp(namespaced_name, head_name)) {
1078                         switch (deny_delete_current) {
1079                         case DENY_IGNORE:
1080                                 break;
1081                         case DENY_WARN:
1082                                 rp_warning("deleting the current branch");
1083                                 break;
1084                         case DENY_REFUSE:
1085                         case DENY_UNCONFIGURED:
1086                         case DENY_UPDATE_INSTEAD:
1087                                 if (deny_delete_current == DENY_UNCONFIGURED)
1088                                         refuse_unconfigured_deny_delete_current();
1089                                 rp_error("refusing to delete the current branch: %s", name);
1090                                 return "deletion of the current branch prohibited";
1091                         default:
1092                                 return "Invalid denyDeleteCurrent setting";
1093                         }
1094                 }
1095         }
1096
1097         if (deny_non_fast_forwards && !is_null_oid(new_oid) &&
1098             !is_null_oid(old_oid) &&
1099             starts_with(name, "refs/heads/")) {
1100                 struct object *old_object, *new_object;
1101                 struct commit *old_commit, *new_commit;
1102
1103                 old_object = parse_object(old_oid->hash);
1104                 new_object = parse_object(new_oid->hash);
1105
1106                 if (!old_object || !new_object ||
1107                     old_object->type != OBJ_COMMIT ||
1108                     new_object->type != OBJ_COMMIT) {
1109                         error("bad sha1 objects for %s", name);
1110                         return "bad ref";
1111                 }
1112                 old_commit = (struct commit *)old_object;
1113                 new_commit = (struct commit *)new_object;
1114                 if (!in_merge_bases(old_commit, new_commit)) {
1115                         rp_error("denying non-fast-forward %s"
1116                                  " (you should pull first)", name);
1117                         return "non-fast-forward";
1118                 }
1119         }
1120         if (run_update_hook(cmd)) {
1121                 rp_error("hook declined to update %s", name);
1122                 return "hook declined";
1123         }
1124
1125         if (is_null_oid(new_oid)) {
1126                 struct strbuf err = STRBUF_INIT;
1127                 if (!parse_object(old_oid->hash)) {
1128                         old_oid = NULL;
1129                         if (ref_exists(name)) {
1130                                 rp_warning("Allowing deletion of corrupt ref.");
1131                         } else {
1132                                 rp_warning("Deleting a non-existent ref.");
1133                                 cmd->did_not_exist = 1;
1134                         }
1135                 }
1136                 if (ref_transaction_delete(transaction,
1137                                            namespaced_name,
1138                                            old_oid->hash,
1139                                            0, "push", &err)) {
1140                         rp_error("%s", err.buf);
1141                         strbuf_release(&err);
1142                         return "failed to delete";
1143                 }
1144                 strbuf_release(&err);
1145                 return NULL; /* good */
1146         }
1147         else {
1148                 struct strbuf err = STRBUF_INIT;
1149                 if (shallow_update && si->shallow_ref[cmd->index] &&
1150                     update_shallow_ref(cmd, si))
1151                         return "shallow error";
1152
1153                 if (ref_transaction_update(transaction,
1154                                            namespaced_name,
1155                                            new_oid->hash, old_oid->hash,
1156                                            0, "push",
1157                                            &err)) {
1158                         rp_error("%s", err.buf);
1159                         strbuf_release(&err);
1160
1161                         return "failed to update ref";
1162                 }
1163                 strbuf_release(&err);
1164
1165                 return NULL; /* good */
1166         }
1167 }
1168
1169 static void run_update_post_hook(struct command *commands)
1170 {
1171         struct command *cmd;
1172         struct child_process proc = CHILD_PROCESS_INIT;
1173         const char *hook;
1174
1175         hook = find_hook("post-update");
1176         if (!hook)
1177                 return;
1178
1179         for (cmd = commands; cmd; cmd = cmd->next) {
1180                 if (cmd->error_string || cmd->did_not_exist)
1181                         continue;
1182                 if (!proc.args.argc)
1183                         argv_array_push(&proc.args, hook);
1184                 argv_array_push(&proc.args, cmd->ref_name);
1185         }
1186         if (!proc.args.argc)
1187                 return;
1188
1189         proc.no_stdin = 1;
1190         proc.stdout_to_stderr = 1;
1191         proc.err = use_sideband ? -1 : 0;
1192
1193         if (!start_command(&proc)) {
1194                 if (use_sideband)
1195                         copy_to_sideband(proc.err, -1, NULL);
1196                 finish_command(&proc);
1197         }
1198 }
1199
1200 static void check_aliased_update(struct command *cmd, struct string_list *list)
1201 {
1202         struct strbuf buf = STRBUF_INIT;
1203         const char *dst_name;
1204         struct string_list_item *item;
1205         struct command *dst_cmd;
1206         unsigned char sha1[GIT_MAX_RAWSZ];
1207         int flag;
1208
1209         strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
1210         dst_name = resolve_ref_unsafe(buf.buf, 0, sha1, &flag);
1211         strbuf_release(&buf);
1212
1213         if (!(flag & REF_ISSYMREF))
1214                 return;
1215
1216         if (!dst_name) {
1217                 rp_error("refusing update to broken symref '%s'", cmd->ref_name);
1218                 cmd->skip_update = 1;
1219                 cmd->error_string = "broken symref";
1220                 return;
1221         }
1222         dst_name = strip_namespace(dst_name);
1223
1224         if ((item = string_list_lookup(list, dst_name)) == NULL)
1225                 return;
1226
1227         cmd->skip_update = 1;
1228
1229         dst_cmd = (struct command *) item->util;
1230
1231         if (!oidcmp(&cmd->old_oid, &dst_cmd->old_oid) &&
1232             !oidcmp(&cmd->new_oid, &dst_cmd->new_oid))
1233                 return;
1234
1235         dst_cmd->skip_update = 1;
1236
1237         rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
1238                  " its target '%s' (%s..%s)",
1239                  cmd->ref_name,
1240                  find_unique_abbrev(cmd->old_oid.hash, DEFAULT_ABBREV),
1241                  find_unique_abbrev(cmd->new_oid.hash, DEFAULT_ABBREV),
1242                  dst_cmd->ref_name,
1243                  find_unique_abbrev(dst_cmd->old_oid.hash, DEFAULT_ABBREV),
1244                  find_unique_abbrev(dst_cmd->new_oid.hash, DEFAULT_ABBREV));
1245
1246         cmd->error_string = dst_cmd->error_string =
1247                 "inconsistent aliased update";
1248 }
1249
1250 static void check_aliased_updates(struct command *commands)
1251 {
1252         struct command *cmd;
1253         struct string_list ref_list = STRING_LIST_INIT_NODUP;
1254
1255         for (cmd = commands; cmd; cmd = cmd->next) {
1256                 struct string_list_item *item =
1257                         string_list_append(&ref_list, cmd->ref_name);
1258                 item->util = (void *)cmd;
1259         }
1260         string_list_sort(&ref_list);
1261
1262         for (cmd = commands; cmd; cmd = cmd->next) {
1263                 if (!cmd->error_string)
1264                         check_aliased_update(cmd, &ref_list);
1265         }
1266
1267         string_list_clear(&ref_list, 0);
1268 }
1269
1270 static int command_singleton_iterator(void *cb_data, unsigned char sha1[20])
1271 {
1272         struct command **cmd_list = cb_data;
1273         struct command *cmd = *cmd_list;
1274
1275         if (!cmd || is_null_oid(&cmd->new_oid))
1276                 return -1; /* end of list */
1277         *cmd_list = NULL; /* this returns only one */
1278         hashcpy(sha1, cmd->new_oid.hash);
1279         return 0;
1280 }
1281
1282 static void set_connectivity_errors(struct command *commands,
1283                                     struct shallow_info *si)
1284 {
1285         struct command *cmd;
1286
1287         for (cmd = commands; cmd; cmd = cmd->next) {
1288                 struct command *singleton = cmd;
1289                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1290
1291                 if (shallow_update && si->shallow_ref[cmd->index])
1292                         /* to be checked in update_shallow_ref() */
1293                         continue;
1294
1295                 opt.env = tmp_objdir_env(tmp_objdir);
1296                 if (!check_connected(command_singleton_iterator, &singleton,
1297                                      &opt))
1298                         continue;
1299
1300                 cmd->error_string = "missing necessary objects";
1301         }
1302 }
1303
1304 struct iterate_data {
1305         struct command *cmds;
1306         struct shallow_info *si;
1307 };
1308
1309 static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
1310 {
1311         struct iterate_data *data = cb_data;
1312         struct command **cmd_list = &data->cmds;
1313         struct command *cmd = *cmd_list;
1314
1315         for (; cmd; cmd = cmd->next) {
1316                 if (shallow_update && data->si->shallow_ref[cmd->index])
1317                         /* to be checked in update_shallow_ref() */
1318                         continue;
1319                 if (!is_null_oid(&cmd->new_oid) && !cmd->skip_update) {
1320                         hashcpy(sha1, cmd->new_oid.hash);
1321                         *cmd_list = cmd->next;
1322                         return 0;
1323                 }
1324         }
1325         *cmd_list = NULL;
1326         return -1; /* end of list */
1327 }
1328
1329 static void reject_updates_to_hidden(struct command *commands)
1330 {
1331         struct strbuf refname_full = STRBUF_INIT;
1332         size_t prefix_len;
1333         struct command *cmd;
1334
1335         strbuf_addstr(&refname_full, get_git_namespace());
1336         prefix_len = refname_full.len;
1337
1338         for (cmd = commands; cmd; cmd = cmd->next) {
1339                 if (cmd->error_string)
1340                         continue;
1341
1342                 strbuf_setlen(&refname_full, prefix_len);
1343                 strbuf_addstr(&refname_full, cmd->ref_name);
1344
1345                 if (!ref_is_hidden(cmd->ref_name, refname_full.buf))
1346                         continue;
1347                 if (is_null_oid(&cmd->new_oid))
1348                         cmd->error_string = "deny deleting a hidden ref";
1349                 else
1350                         cmd->error_string = "deny updating a hidden ref";
1351         }
1352
1353         strbuf_release(&refname_full);
1354 }
1355
1356 static int should_process_cmd(struct command *cmd)
1357 {
1358         return !cmd->error_string && !cmd->skip_update;
1359 }
1360
1361 static void warn_if_skipped_connectivity_check(struct command *commands,
1362                                                struct shallow_info *si)
1363 {
1364         struct command *cmd;
1365         int checked_connectivity = 1;
1366
1367         for (cmd = commands; cmd; cmd = cmd->next) {
1368                 if (should_process_cmd(cmd) && si->shallow_ref[cmd->index]) {
1369                         error("BUG: connectivity check has not been run on ref %s",
1370                               cmd->ref_name);
1371                         checked_connectivity = 0;
1372                 }
1373         }
1374         if (!checked_connectivity)
1375                 die("BUG: connectivity check skipped???");
1376 }
1377
1378 static void execute_commands_non_atomic(struct command *commands,
1379                                         struct shallow_info *si)
1380 {
1381         struct command *cmd;
1382         struct strbuf err = STRBUF_INIT;
1383
1384         for (cmd = commands; cmd; cmd = cmd->next) {
1385                 if (!should_process_cmd(cmd))
1386                         continue;
1387
1388                 transaction = ref_transaction_begin(&err);
1389                 if (!transaction) {
1390                         rp_error("%s", err.buf);
1391                         strbuf_reset(&err);
1392                         cmd->error_string = "transaction failed to start";
1393                         continue;
1394                 }
1395
1396                 cmd->error_string = update(cmd, si);
1397
1398                 if (!cmd->error_string
1399                     && ref_transaction_commit(transaction, &err)) {
1400                         rp_error("%s", err.buf);
1401                         strbuf_reset(&err);
1402                         cmd->error_string = "failed to update ref";
1403                 }
1404                 ref_transaction_free(transaction);
1405         }
1406         strbuf_release(&err);
1407 }
1408
1409 static void execute_commands_atomic(struct command *commands,
1410                                         struct shallow_info *si)
1411 {
1412         struct command *cmd;
1413         struct strbuf err = STRBUF_INIT;
1414         const char *reported_error = "atomic push failure";
1415
1416         transaction = ref_transaction_begin(&err);
1417         if (!transaction) {
1418                 rp_error("%s", err.buf);
1419                 strbuf_reset(&err);
1420                 reported_error = "transaction failed to start";
1421                 goto failure;
1422         }
1423
1424         for (cmd = commands; cmd; cmd = cmd->next) {
1425                 if (!should_process_cmd(cmd))
1426                         continue;
1427
1428                 cmd->error_string = update(cmd, si);
1429
1430                 if (cmd->error_string)
1431                         goto failure;
1432         }
1433
1434         if (ref_transaction_commit(transaction, &err)) {
1435                 rp_error("%s", err.buf);
1436                 reported_error = "atomic transaction failed";
1437                 goto failure;
1438         }
1439         goto cleanup;
1440
1441 failure:
1442         for (cmd = commands; cmd; cmd = cmd->next)
1443                 if (!cmd->error_string)
1444                         cmd->error_string = reported_error;
1445
1446 cleanup:
1447         ref_transaction_free(transaction);
1448         strbuf_release(&err);
1449 }
1450
1451 static void execute_commands(struct command *commands,
1452                              const char *unpacker_error,
1453                              struct shallow_info *si,
1454                              const struct string_list *push_options)
1455 {
1456         struct check_connected_options opt = CHECK_CONNECTED_INIT;
1457         struct command *cmd;
1458         struct object_id oid;
1459         struct iterate_data data;
1460         struct async muxer;
1461         int err_fd = 0;
1462
1463         if (unpacker_error) {
1464                 for (cmd = commands; cmd; cmd = cmd->next)
1465                         cmd->error_string = "unpacker error";
1466                 return;
1467         }
1468
1469         if (use_sideband) {
1470                 memset(&muxer, 0, sizeof(muxer));
1471                 muxer.proc = copy_to_sideband;
1472                 muxer.in = -1;
1473                 if (!start_async(&muxer))
1474                         err_fd = muxer.in;
1475                 /* ...else, continue without relaying sideband */
1476         }
1477
1478         data.cmds = commands;
1479         data.si = si;
1480         opt.err_fd = err_fd;
1481         opt.progress = err_fd && !quiet;
1482         opt.env = tmp_objdir_env(tmp_objdir);
1483         if (check_connected(iterate_receive_command_list, &data, &opt))
1484                 set_connectivity_errors(commands, si);
1485
1486         if (use_sideband)
1487                 finish_async(&muxer);
1488
1489         reject_updates_to_hidden(commands);
1490
1491         if (run_receive_hook(commands, "pre-receive", 0, push_options)) {
1492                 for (cmd = commands; cmd; cmd = cmd->next) {
1493                         if (!cmd->error_string)
1494                                 cmd->error_string = "pre-receive hook declined";
1495                 }
1496                 return;
1497         }
1498
1499         /*
1500          * Now we'll start writing out refs, which means the objects need
1501          * to be in their final positions so that other processes can see them.
1502          */
1503         if (tmp_objdir_migrate(tmp_objdir) < 0) {
1504                 for (cmd = commands; cmd; cmd = cmd->next) {
1505                         if (!cmd->error_string)
1506                                 cmd->error_string = "unable to migrate objects to permanent storage";
1507                 }
1508                 return;
1509         }
1510         tmp_objdir = NULL;
1511
1512         check_aliased_updates(commands);
1513
1514         free(head_name_to_free);
1515         head_name = head_name_to_free = resolve_refdup("HEAD", 0, oid.hash, NULL);
1516
1517         if (use_atomic)
1518                 execute_commands_atomic(commands, si);
1519         else
1520                 execute_commands_non_atomic(commands, si);
1521
1522         if (shallow_update)
1523                 warn_if_skipped_connectivity_check(commands, si);
1524 }
1525
1526 static struct command **queue_command(struct command **tail,
1527                                       const char *line,
1528                                       int linelen)
1529 {
1530         struct object_id old_oid, new_oid;
1531         struct command *cmd;
1532         const char *refname;
1533         int reflen;
1534         const char *p;
1535
1536         if (parse_oid_hex(line, &old_oid, &p) ||
1537             *p++ != ' ' ||
1538             parse_oid_hex(p, &new_oid, &p) ||
1539             *p++ != ' ')
1540                 die("protocol error: expected old/new/ref, got '%s'", line);
1541
1542         refname = p;
1543         reflen = linelen - (p - line);
1544         FLEX_ALLOC_MEM(cmd, ref_name, refname, reflen);
1545         oidcpy(&cmd->old_oid, &old_oid);
1546         oidcpy(&cmd->new_oid, &new_oid);
1547         *tail = cmd;
1548         return &cmd->next;
1549 }
1550
1551 static void queue_commands_from_cert(struct command **tail,
1552                                      struct strbuf *push_cert)
1553 {
1554         const char *boc, *eoc;
1555
1556         if (*tail)
1557                 die("protocol error: got both push certificate and unsigned commands");
1558
1559         boc = strstr(push_cert->buf, "\n\n");
1560         if (!boc)
1561                 die("malformed push certificate %.*s", 100, push_cert->buf);
1562         else
1563                 boc += 2;
1564         eoc = push_cert->buf + parse_signature(push_cert->buf, push_cert->len);
1565
1566         while (boc < eoc) {
1567                 const char *eol = memchr(boc, '\n', eoc - boc);
1568                 tail = queue_command(tail, boc, eol ? eol - boc : eoc - boc);
1569                 boc = eol ? eol + 1 : eoc;
1570         }
1571 }
1572
1573 static struct command *read_head_info(struct oid_array *shallow)
1574 {
1575         struct command *commands = NULL;
1576         struct command **p = &commands;
1577         for (;;) {
1578                 char *line;
1579                 int len, linelen;
1580
1581                 line = packet_read_line(0, &len);
1582                 if (!line)
1583                         break;
1584
1585                 if (len > 8 && starts_with(line, "shallow ")) {
1586                         struct object_id oid;
1587                         if (get_oid_hex(line + 8, &oid))
1588                                 die("protocol error: expected shallow sha, got '%s'",
1589                                     line + 8);
1590                         oid_array_append(shallow, &oid);
1591                         continue;
1592                 }
1593
1594                 linelen = strlen(line);
1595                 if (linelen < len) {
1596                         const char *feature_list = line + linelen + 1;
1597                         if (parse_feature_request(feature_list, "report-status"))
1598                                 report_status = 1;
1599                         if (parse_feature_request(feature_list, "side-band-64k"))
1600                                 use_sideband = LARGE_PACKET_MAX;
1601                         if (parse_feature_request(feature_list, "quiet"))
1602                                 quiet = 1;
1603                         if (advertise_atomic_push
1604                             && parse_feature_request(feature_list, "atomic"))
1605                                 use_atomic = 1;
1606                         if (advertise_push_options
1607                             && parse_feature_request(feature_list, "push-options"))
1608                                 use_push_options = 1;
1609                 }
1610
1611                 if (!strcmp(line, "push-cert")) {
1612                         int true_flush = 0;
1613                         char certbuf[1024];
1614
1615                         for (;;) {
1616                                 len = packet_read(0, NULL, NULL,
1617                                                   certbuf, sizeof(certbuf), 0);
1618                                 if (!len) {
1619                                         true_flush = 1;
1620                                         break;
1621                                 }
1622                                 if (!strcmp(certbuf, "push-cert-end\n"))
1623                                         break; /* end of cert */
1624                                 strbuf_addstr(&push_cert, certbuf);
1625                         }
1626
1627                         if (true_flush)
1628                                 break;
1629                         continue;
1630                 }
1631
1632                 p = queue_command(p, line, linelen);
1633         }
1634
1635         if (push_cert.len)
1636                 queue_commands_from_cert(p, &push_cert);
1637
1638         return commands;
1639 }
1640
1641 static void read_push_options(struct string_list *options)
1642 {
1643         while (1) {
1644                 char *line;
1645                 int len;
1646
1647                 line = packet_read_line(0, &len);
1648
1649                 if (!line)
1650                         break;
1651
1652                 string_list_append(options, line);
1653         }
1654 }
1655
1656 static const char *parse_pack_header(struct pack_header *hdr)
1657 {
1658         switch (read_pack_header(0, hdr)) {
1659         case PH_ERROR_EOF:
1660                 return "eof before pack header was fully read";
1661
1662         case PH_ERROR_PACK_SIGNATURE:
1663                 return "protocol error (pack signature mismatch detected)";
1664
1665         case PH_ERROR_PROTOCOL:
1666                 return "protocol error (pack version unsupported)";
1667
1668         default:
1669                 return "unknown error in parse_pack_header";
1670
1671         case 0:
1672                 return NULL;
1673         }
1674 }
1675
1676 static const char *pack_lockfile;
1677
1678 static void push_header_arg(struct argv_array *args, struct pack_header *hdr)
1679 {
1680         argv_array_pushf(args, "--pack_header=%"PRIu32",%"PRIu32,
1681                         ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
1682 }
1683
1684 static const char *unpack(int err_fd, struct shallow_info *si)
1685 {
1686         struct pack_header hdr;
1687         const char *hdr_err;
1688         int status;
1689         struct child_process child = CHILD_PROCESS_INIT;
1690         int fsck_objects = (receive_fsck_objects >= 0
1691                             ? receive_fsck_objects
1692                             : transfer_fsck_objects >= 0
1693                             ? transfer_fsck_objects
1694                             : 0);
1695
1696         hdr_err = parse_pack_header(&hdr);
1697         if (hdr_err) {
1698                 if (err_fd > 0)
1699                         close(err_fd);
1700                 return hdr_err;
1701         }
1702
1703         if (si->nr_ours || si->nr_theirs) {
1704                 alt_shallow_file = setup_temporary_shallow(si->shallow);
1705                 argv_array_push(&child.args, "--shallow-file");
1706                 argv_array_push(&child.args, alt_shallow_file);
1707         }
1708
1709         tmp_objdir = tmp_objdir_create();
1710         if (!tmp_objdir) {
1711                 if (err_fd > 0)
1712                         close(err_fd);
1713                 return "unable to create temporary object directory";
1714         }
1715         child.env = tmp_objdir_env(tmp_objdir);
1716
1717         /*
1718          * Normally we just pass the tmp_objdir environment to the child
1719          * processes that do the heavy lifting, but we may need to see these
1720          * objects ourselves to set up shallow information.
1721          */
1722         tmp_objdir_add_as_alternate(tmp_objdir);
1723
1724         if (ntohl(hdr.hdr_entries) < unpack_limit) {
1725                 argv_array_push(&child.args, "unpack-objects");
1726                 push_header_arg(&child.args, &hdr);
1727                 if (quiet)
1728                         argv_array_push(&child.args, "-q");
1729                 if (fsck_objects)
1730                         argv_array_pushf(&child.args, "--strict%s",
1731                                 fsck_msg_types.buf);
1732                 if (max_input_size)
1733                         argv_array_pushf(&child.args, "--max-input-size=%"PRIuMAX,
1734                                 (uintmax_t)max_input_size);
1735                 child.no_stdout = 1;
1736                 child.err = err_fd;
1737                 child.git_cmd = 1;
1738                 status = run_command(&child);
1739                 if (status)
1740                         return "unpack-objects abnormal exit";
1741         } else {
1742                 char hostname[HOST_NAME_MAX + 1];
1743
1744                 argv_array_pushl(&child.args, "index-pack", "--stdin", NULL);
1745                 push_header_arg(&child.args, &hdr);
1746
1747                 if (xgethostname(hostname, sizeof(hostname)))
1748                         xsnprintf(hostname, sizeof(hostname), "localhost");
1749                 argv_array_pushf(&child.args,
1750                                  "--keep=receive-pack %"PRIuMAX" on %s",
1751                                  (uintmax_t)getpid(),
1752                                  hostname);
1753
1754                 if (!quiet && err_fd)
1755                         argv_array_push(&child.args, "--show-resolving-progress");
1756                 if (use_sideband)
1757                         argv_array_push(&child.args, "--report-end-of-input");
1758                 if (fsck_objects)
1759                         argv_array_pushf(&child.args, "--strict%s",
1760                                 fsck_msg_types.buf);
1761                 if (!reject_thin)
1762                         argv_array_push(&child.args, "--fix-thin");
1763                 if (max_input_size)
1764                         argv_array_pushf(&child.args, "--max-input-size=%"PRIuMAX,
1765                                 (uintmax_t)max_input_size);
1766                 child.out = -1;
1767                 child.err = err_fd;
1768                 child.git_cmd = 1;
1769                 status = start_command(&child);
1770                 if (status)
1771                         return "index-pack fork failed";
1772                 pack_lockfile = index_pack_lockfile(child.out);
1773                 close(child.out);
1774                 status = finish_command(&child);
1775                 if (status)
1776                         return "index-pack abnormal exit";
1777                 reprepare_packed_git();
1778         }
1779         return NULL;
1780 }
1781
1782 static const char *unpack_with_sideband(struct shallow_info *si)
1783 {
1784         struct async muxer;
1785         const char *ret;
1786
1787         if (!use_sideband)
1788                 return unpack(0, si);
1789
1790         use_keepalive = KEEPALIVE_AFTER_NUL;
1791         memset(&muxer, 0, sizeof(muxer));
1792         muxer.proc = copy_to_sideband;
1793         muxer.in = -1;
1794         if (start_async(&muxer))
1795                 return NULL;
1796
1797         ret = unpack(muxer.in, si);
1798
1799         finish_async(&muxer);
1800         return ret;
1801 }
1802
1803 static void prepare_shallow_update(struct command *commands,
1804                                    struct shallow_info *si)
1805 {
1806         int i, j, k, bitmap_size = (si->ref->nr + 31) / 32;
1807
1808         ALLOC_ARRAY(si->used_shallow, si->shallow->nr);
1809         assign_shallow_commits_to_refs(si, si->used_shallow, NULL);
1810
1811         si->need_reachability_test =
1812                 xcalloc(si->shallow->nr, sizeof(*si->need_reachability_test));
1813         si->reachable =
1814                 xcalloc(si->shallow->nr, sizeof(*si->reachable));
1815         si->shallow_ref = xcalloc(si->ref->nr, sizeof(*si->shallow_ref));
1816
1817         for (i = 0; i < si->nr_ours; i++)
1818                 si->need_reachability_test[si->ours[i]] = 1;
1819
1820         for (i = 0; i < si->shallow->nr; i++) {
1821                 if (!si->used_shallow[i])
1822                         continue;
1823                 for (j = 0; j < bitmap_size; j++) {
1824                         if (!si->used_shallow[i][j])
1825                                 continue;
1826                         si->need_reachability_test[i]++;
1827                         for (k = 0; k < 32; k++)
1828                                 if (si->used_shallow[i][j] & (1U << k))
1829                                         si->shallow_ref[j * 32 + k]++;
1830                 }
1831
1832                 /*
1833                  * true for those associated with some refs and belong
1834                  * in "ours" list aka "step 7 not done yet"
1835                  */
1836                 si->need_reachability_test[i] =
1837                         si->need_reachability_test[i] > 1;
1838         }
1839
1840         /*
1841          * keep hooks happy by forcing a temporary shallow file via
1842          * env variable because we can't add --shallow-file to every
1843          * command. check_everything_connected() will be done with
1844          * true .git/shallow though.
1845          */
1846         setenv(GIT_SHALLOW_FILE_ENVIRONMENT, alt_shallow_file, 1);
1847 }
1848
1849 static void update_shallow_info(struct command *commands,
1850                                 struct shallow_info *si,
1851                                 struct oid_array *ref)
1852 {
1853         struct command *cmd;
1854         int *ref_status;
1855         remove_nonexistent_theirs_shallow(si);
1856         if (!si->nr_ours && !si->nr_theirs) {
1857                 shallow_update = 0;
1858                 return;
1859         }
1860
1861         for (cmd = commands; cmd; cmd = cmd->next) {
1862                 if (is_null_oid(&cmd->new_oid))
1863                         continue;
1864                 oid_array_append(ref, &cmd->new_oid);
1865                 cmd->index = ref->nr - 1;
1866         }
1867         si->ref = ref;
1868
1869         if (shallow_update) {
1870                 prepare_shallow_update(commands, si);
1871                 return;
1872         }
1873
1874         ALLOC_ARRAY(ref_status, ref->nr);
1875         assign_shallow_commits_to_refs(si, NULL, ref_status);
1876         for (cmd = commands; cmd; cmd = cmd->next) {
1877                 if (is_null_oid(&cmd->new_oid))
1878                         continue;
1879                 if (ref_status[cmd->index]) {
1880                         cmd->error_string = "shallow update not allowed";
1881                         cmd->skip_update = 1;
1882                 }
1883         }
1884         free(ref_status);
1885 }
1886
1887 static void report(struct command *commands, const char *unpack_status)
1888 {
1889         struct command *cmd;
1890         struct strbuf buf = STRBUF_INIT;
1891
1892         packet_buf_write(&buf, "unpack %s\n",
1893                          unpack_status ? unpack_status : "ok");
1894         for (cmd = commands; cmd; cmd = cmd->next) {
1895                 if (!cmd->error_string)
1896                         packet_buf_write(&buf, "ok %s\n",
1897                                          cmd->ref_name);
1898                 else
1899                         packet_buf_write(&buf, "ng %s %s\n",
1900                                          cmd->ref_name, cmd->error_string);
1901         }
1902         packet_buf_flush(&buf);
1903
1904         if (use_sideband)
1905                 send_sideband(1, 1, buf.buf, buf.len, use_sideband);
1906         else
1907                 write_or_die(1, buf.buf, buf.len);
1908         strbuf_release(&buf);
1909 }
1910
1911 static int delete_only(struct command *commands)
1912 {
1913         struct command *cmd;
1914         for (cmd = commands; cmd; cmd = cmd->next) {
1915                 if (!is_null_oid(&cmd->new_oid))
1916                         return 0;
1917         }
1918         return 1;
1919 }
1920
1921 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
1922 {
1923         int advertise_refs = 0;
1924         struct command *commands;
1925         struct oid_array shallow = OID_ARRAY_INIT;
1926         struct oid_array ref = OID_ARRAY_INIT;
1927         struct shallow_info si;
1928
1929         struct option options[] = {
1930                 OPT__QUIET(&quiet, N_("quiet")),
1931                 OPT_HIDDEN_BOOL(0, "stateless-rpc", &stateless_rpc, NULL),
1932                 OPT_HIDDEN_BOOL(0, "advertise-refs", &advertise_refs, NULL),
1933                 OPT_HIDDEN_BOOL(0, "reject-thin-pack-for-testing", &reject_thin, NULL),
1934                 OPT_END()
1935         };
1936
1937         packet_trace_identity("receive-pack");
1938
1939         argc = parse_options(argc, argv, prefix, options, receive_pack_usage, 0);
1940
1941         if (argc > 1)
1942                 usage_msg_opt(_("Too many arguments."), receive_pack_usage, options);
1943         if (argc == 0)
1944                 usage_msg_opt(_("You must specify a directory."), receive_pack_usage, options);
1945
1946         service_dir = argv[0];
1947
1948         setup_path();
1949
1950         if (!enter_repo(service_dir, 0))
1951                 die("'%s' does not appear to be a git repository", service_dir);
1952
1953         git_config(receive_pack_config, NULL);
1954         if (cert_nonce_seed)
1955                 push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL));
1956
1957         if (0 <= transfer_unpack_limit)
1958                 unpack_limit = transfer_unpack_limit;
1959         else if (0 <= receive_unpack_limit)
1960                 unpack_limit = receive_unpack_limit;
1961
1962         if (advertise_refs || !stateless_rpc) {
1963                 write_head_info();
1964         }
1965         if (advertise_refs)
1966                 return 0;
1967
1968         if ((commands = read_head_info(&shallow)) != NULL) {
1969                 const char *unpack_status = NULL;
1970                 struct string_list push_options = STRING_LIST_INIT_DUP;
1971
1972                 if (use_push_options)
1973                         read_push_options(&push_options);
1974                 if (!check_cert_push_options(&push_options)) {
1975                         struct command *cmd;
1976                         for (cmd = commands; cmd; cmd = cmd->next)
1977                                 cmd->error_string = "inconsistent push options";
1978                 }
1979
1980                 prepare_shallow_info(&si, &shallow);
1981                 if (!si.nr_ours && !si.nr_theirs)
1982                         shallow_update = 0;
1983                 if (!delete_only(commands)) {
1984                         unpack_status = unpack_with_sideband(&si);
1985                         update_shallow_info(commands, &si, &ref);
1986                 }
1987                 use_keepalive = KEEPALIVE_ALWAYS;
1988                 execute_commands(commands, unpack_status, &si,
1989                                  &push_options);
1990                 if (pack_lockfile)
1991                         unlink_or_warn(pack_lockfile);
1992                 if (report_status)
1993                         report(commands, unpack_status);
1994                 run_receive_hook(commands, "post-receive", 1,
1995                                  &push_options);
1996                 run_update_post_hook(commands);
1997                 string_list_clear(&push_options, 0);
1998                 if (auto_gc) {
1999                         const char *argv_gc_auto[] = {
2000                                 "gc", "--auto", "--quiet", NULL,
2001                         };
2002                         struct child_process proc = CHILD_PROCESS_INIT;
2003
2004                         proc.no_stdin = 1;
2005                         proc.stdout_to_stderr = 1;
2006                         proc.err = use_sideband ? -1 : 0;
2007                         proc.git_cmd = 1;
2008                         proc.argv = argv_gc_auto;
2009
2010                         close_all_packs();
2011                         if (!start_command(&proc)) {
2012                                 if (use_sideband)
2013                                         copy_to_sideband(proc.err, -1, NULL);
2014                                 finish_command(&proc);
2015                         }
2016                 }
2017                 if (auto_update_server_info)
2018                         update_server_info(0);
2019                 clear_shallow_info(&si);
2020         }
2021         if (use_sideband)
2022                 packet_flush(1);
2023         oid_array_clear(&shallow);
2024         oid_array_clear(&ref);
2025         free((void *)push_cert_nonce);
2026         return 0;
2027 }