builtin/init-db.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7 #include "config.h"
   8 #include "refs.h"
   9 #include "builtin.h"
  10 #include "exec-cmd.h"
  11 #include "parse-options.h"
  12 #include "worktree.h"
  13
  14 #ifndef DEFAULT_GIT_TEMPLATE_DIR
  15 #define DEFAULT_GIT_TEMPLATE_DIR "/usr/share/git-core/templates"
  16 #endif
  17
  18 #ifdef NO_TRUSTABLE_FILEMODE
  19 #define TEST_FILEMODE 0
  20 #else
  21 #define TEST_FILEMODE 1
  22 #endif
  23
  24 #define GIT_DEFAULT_HASH_ENVIRONMENT "GIT_DEFAULT_HASH"
  25
  26 static int init_is_bare_repository = 0;
  27 static int init_shared_repository = -1;
  28 static const char *init_db_template_dir;
  29
  30 static void copy_templates_1(struct strbuf *path, struct strbuf *template_path,
  31                              DIR *dir)
  32 {
  33         size_t path_baselen = path->len;
  34         size_t template_baselen = template_path->len;
  35         struct dirent *de;
  36
  37         /* Note: if ".git/hooks" file exists in the repository being
  38          * re-initialized, /etc/core-git/templates/hooks/update would
  39          * cause "git init" to fail here.  I think this is sane but
  40          * it means that the set of templates we ship by default, along
  41          * with the way the namespace under .git/ is organized, should
  42          * be really carefully chosen.
  43          */
  44         safe_create_dir(path->buf, 1);
  45         while ((de = readdir(dir)) != NULL) {
  46                 struct stat st_git, st_template;
  47                 int exists = 0;
  48
  49                 strbuf_setlen(path, path_baselen);
  50                 strbuf_setlen(template_path, template_baselen);
  51
  52                 if (de->d_name[0] == '.')
  53                         continue;
  54                 strbuf_addstr(path, de->d_name);
  55                 strbuf_addstr(template_path, de->d_name);
  56                 if (lstat(path->buf, &st_git)) {
  57                         if (errno != ENOENT)
  58                                 die_errno(_("cannot stat '%s'"), path->buf);
  59                 }
  60                 else
  61                         exists = 1;
  62
  63                 if (lstat(template_path->buf, &st_template))
  64                         die_errno(_("cannot stat template '%s'"), template_path->buf);
  65
  66                 if (S_ISDIR(st_template.st_mode)) {
  67                         DIR *subdir = opendir(template_path->buf);
  68                         if (!subdir)
  69                                 die_errno(_("cannot opendir '%s'"), template_path->buf);
  70                         strbuf_addch(path, '/');
  71                         strbuf_addch(template_path, '/');
  72                         copy_templates_1(path, template_path, subdir);
  73                         closedir(subdir);
  74                 }
  75                 else if (exists)
  76                         continue;
  77                 else if (S_ISLNK(st_template.st_mode)) {
  78                         struct strbuf lnk = STRBUF_INIT;
  79                         if (strbuf_readlink(&lnk, template_path->buf,
  80                                             st_template.st_size) < 0)
  81                                 die_errno(_("cannot readlink '%s'"), template_path->buf);
  82                         if (symlink(lnk.buf, path->buf))
  83                                 die_errno(_("cannot symlink '%s' '%s'"),
  84                                           lnk.buf, path->buf);
  85                         strbuf_release(&lnk);
  86                 }
  87                 else if (S_ISREG(st_template.st_mode)) {
  88                         if (copy_file(path->buf, template_path->buf, st_template.st_mode))
  89                                 die_errno(_("cannot copy '%s' to '%s'"),
  90                                           template_path->buf, path->buf);
  91                 }
  92                 else
  93                         error(_("ignoring template %s"), template_path->buf);
  94         }
  95 }
  96
  97 static void copy_templates(const char *template_dir)
  98 {
  99         struct strbuf path = STRBUF_INIT;
 100         struct strbuf template_path = STRBUF_INIT;
 101         size_t template_len;
 102         struct repository_format template_format = REPOSITORY_FORMAT_INIT;
 103         struct strbuf err = STRBUF_INIT;
 104         DIR *dir;
 105         char *to_free = NULL;
 106
 107         if (!template_dir)
 108                 template_dir = getenv(TEMPLATE_DIR_ENVIRONMENT);
 109         if (!template_dir)
 110                 template_dir = init_db_template_dir;
 111         if (!template_dir)
 112                 template_dir = to_free = system_path(DEFAULT_GIT_TEMPLATE_DIR);
 113         if (!template_dir[0]) {
 114                 free(to_free);
 115                 return;
 116         }
 117
 118         strbuf_addstr(&template_path, template_dir);
 119         strbuf_complete(&template_path, '/');
 120         template_len = template_path.len;
 121
 122         dir = opendir(template_path.buf);
 123         if (!dir) {
 124                 warning(_("templates not found in %s"), template_dir);
 125                 goto free_return;
 126         }
 127
 128         /* Make sure that template is from the correct vintage */
 129         strbuf_addstr(&template_path, "config");
 130         read_repository_format(&template_format, template_path.buf);
 131         strbuf_setlen(&template_path, template_len);
 132
 133         /*
 134          * No mention of version at all is OK, but anything else should be
 135          * verified.
 136          */
 137         if (template_format.version >= 0 &&
 138             verify_repository_format(&template_format, &err) < 0) {
 139                 warning(_("not copying templates from '%s': %s"),
 140                           template_dir, err.buf);
 141                 strbuf_release(&err);
 142                 goto close_free_return;
 143         }
 144
 145         strbuf_addstr(&path, get_git_common_dir());
 146         strbuf_complete(&path, '/');
 147         copy_templates_1(&path, &template_path, dir);
 148 close_free_return:
 149         closedir(dir);
 150 free_return:
 151         free(to_free);
 152         strbuf_release(&path);
 153         strbuf_release(&template_path);
 154         clear_repository_format(&template_format);
 155 }
 156
 157 static int git_init_db_config(const char *k, const char *v, void *cb)
 158 {
 159         if (!strcmp(k, "init.templatedir"))
 160                 return git_config_pathname(&init_db_template_dir, k, v);
 161
 162         if (starts_with(k, "core."))
 163                 return platform_core_config(k, v, cb);
 164
 165         return 0;
 166 }
 167
 168 /*
 169  * If the git_dir is not directly inside the working tree, then git will not
 170  * find it by default, and we need to set the worktree explicitly.
 171  */
 172 static int needs_work_tree_config(const char *git_dir, const char *work_tree)
 173 {
 174         if (!strcmp(work_tree, "/") && !strcmp(git_dir, "/.git"))
 175                 return 0;
 176         if (skip_prefix(git_dir, work_tree, &git_dir) &&
 177             !strcmp(git_dir, "/.git"))
 178                 return 0;
 179         return 1;
 180 }
 181
 182 void initialize_repository_version(int hash_algo, int reinit)
 183 {
 184         char repo_version_string[10];
 185         int repo_version = GIT_REPO_VERSION;
 186
 187         if (hash_algo != GIT_HASH_SHA1)
 188                 repo_version = GIT_REPO_VERSION_READ;
 189
 190         /* This forces creation of new config file */
 191         xsnprintf(repo_version_string, sizeof(repo_version_string),
 192                   "%d", repo_version);
 193         git_config_set("core.repositoryformatversion", repo_version_string);
 194
 195         if (hash_algo != GIT_HASH_SHA1)
 196                 git_config_set("extensions.objectformat",
 197                                hash_algos[hash_algo].name);
 198         else if (reinit)
 199                 git_config_set_gently("extensions.objectformat", NULL);
 200 }
 201
 202 static int create_default_files(const char *template_path,
 203                                 const char *original_git_dir,
 204                                 const char *initial_branch,
 205                                 const struct repository_format *fmt,
 206                                 int quiet)
 207 {
 208         struct stat st1;
 209         struct strbuf buf = STRBUF_INIT;
 210         char *path;
 211         char junk[2];
 212         int reinit;
 213         int filemode;
 214         struct strbuf err = STRBUF_INIT;
 215
 216         /* Just look for `init.templatedir` */
 217         init_db_template_dir = NULL; /* re-set in case it was set before */
 218         git_config(git_init_db_config, NULL);
 219
 220         /*
 221          * First copy the templates -- we might have the default
 222          * config file there, in which case we would want to read
 223          * from it after installing.
 224          *
 225          * Before reading that config, we also need to clear out any cached
 226          * values (since we've just potentially changed what's available on
 227          * disk).
 228          */
 229         copy_templates(template_path);
 230         git_config_clear();
 231         reset_shared_repository();
 232         git_config(git_default_config, NULL);
 233
 234         /*
 235          * We must make sure command-line options continue to override any
 236          * values we might have just re-read from the config.
 237          */
 238         is_bare_repository_cfg = init_is_bare_repository;
 239         if (init_shared_repository != -1)
 240                 set_shared_repository(init_shared_repository);
 241
 242         /*
 243          * We would have created the above under user's umask -- under
 244          * shared-repository settings, we would need to fix them up.
 245          */
 246         if (get_shared_repository()) {
 247                 adjust_shared_perm(get_git_dir());
 248         }
 249
 250         /*
 251          * We need to create a "refs" dir in any case so that older
 252          * versions of git can tell that this is a repository.
 253          */
 254         safe_create_dir(git_path("refs"), 1);
 255         adjust_shared_perm(git_path("refs"));
 256
 257         if (refs_init_db(&err))
 258                 die("failed to set up refs db: %s", err.buf);
 259
 260         /*
 261          * Point the HEAD symref to the initial branch with if HEAD does
 262          * not yet exist.
 263          */
 264         path = git_path_buf(&buf, "HEAD");
 265         reinit = (!access(path, R_OK)
 266                   || readlink(path, junk, sizeof(junk)-1) != -1);
 267         if (!reinit) {
 268                 char *ref;
 269
 270                 if (!initial_branch)
 271                         initial_branch = git_default_branch_name(quiet);
 272
 273                 ref = xstrfmt("refs/heads/%s", initial_branch);
 274                 if (check_refname_format(ref, 0) < 0)
 275                         die(_("invalid initial branch name: '%s'"),
 276                             initial_branch);
 277
 278                 if (create_symref("HEAD", ref, NULL) < 0)
 279                         exit(1);
 280                 free(ref);
 281         }
 282
 283         initialize_repository_version(fmt->hash_algo, 0);
 284
 285         /* Check filemode trustability */
 286         path = git_path_buf(&buf, "config");
 287         filemode = TEST_FILEMODE;
 288         if (TEST_FILEMODE && !lstat(path, &st1)) {
 289                 struct stat st2;
 290                 filemode = (!chmod(path, st1.st_mode ^ S_IXUSR) &&
 291                                 !lstat(path, &st2) &&
 292                                 st1.st_mode != st2.st_mode &&
 293                                 !chmod(path, st1.st_mode));
 294                 if (filemode && !reinit && (st1.st_mode & S_IXUSR))
 295                         filemode = 0;
 296         }
 297         git_config_set("core.filemode", filemode ? "true" : "false");
 298
 299         if (is_bare_repository())
 300                 git_config_set("core.bare", "true");
 301         else {
 302                 const char *work_tree = get_git_work_tree();
 303                 git_config_set("core.bare", "false");
 304                 /* allow template config file to override the default */
 305                 if (log_all_ref_updates == LOG_REFS_UNSET)
 306                         git_config_set("core.logallrefupdates", "true");
 307                 if (needs_work_tree_config(original_git_dir, work_tree))
 308                         git_config_set("core.worktree", work_tree);
 309         }
 310
 311         if (!reinit) {
 312                 /* Check if symlink is supported in the work tree */
 313                 path = git_path_buf(&buf, "tXXXXXX");
 314                 if (!close(xmkstemp(path)) &&
 315                     !unlink(path) &&
 316                     !symlink("testing", path) &&
 317                     !lstat(path, &st1) &&
 318                     S_ISLNK(st1.st_mode))
 319                         unlink(path); /* good */
 320                 else
 321                         git_config_set("core.symlinks", "false");
 322
 323                 /* Check if the filesystem is case-insensitive */
 324                 path = git_path_buf(&buf, "CoNfIg");
 325                 if (!access(path, F_OK))
 326                         git_config_set("core.ignorecase", "true");
 327                 probe_utf8_pathname_composition();
 328         }
 329
 330         strbuf_release(&buf);
 331         return reinit;
 332 }
 333
 334 static void create_object_directory(void)
 335 {
 336         struct strbuf path = STRBUF_INIT;
 337         size_t baselen;
 338
 339         strbuf_addstr(&path, get_object_directory());
 340         baselen = path.len;
 341
 342         safe_create_dir(path.buf, 1);
 343
 344         strbuf_setlen(&path, baselen);
 345         strbuf_addstr(&path, "/pack");
 346         safe_create_dir(path.buf, 1);
 347
 348         strbuf_setlen(&path, baselen);
 349         strbuf_addstr(&path, "/info");
 350         safe_create_dir(path.buf, 1);
 351
 352         strbuf_release(&path);
 353 }
 354
 355 static void separate_git_dir(const char *git_dir, const char *git_link)
 356 {
 357         struct stat st;
 358
 359         if (!stat(git_link, &st)) {
 360                 const char *src;
 361
 362                 if (S_ISREG(st.st_mode))
 363                         src = read_gitfile(git_link);
 364                 else if (S_ISDIR(st.st_mode))
 365                         src = git_link;
 366                 else
 367                         die(_("unable to handle file type %d"), (int)st.st_mode);
 368
 369                 if (rename(src, git_dir))
 370                         die_errno(_("unable to move %s to %s"), src, git_dir);
 371                 repair_worktrees(NULL, NULL);
 372         }
 373
 374         write_file(git_link, "gitdir: %s", git_dir);
 375 }
 376
 377 static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash)
 378 {
 379         const char *env = getenv(GIT_DEFAULT_HASH_ENVIRONMENT);
 380         /*
 381          * If we already have an initialized repo, don't allow the user to
 382          * specify a different algorithm, as that could cause corruption.
 383          * Otherwise, if the user has specified one on the command line, use it.
 384          */
 385         if (repo_fmt->version >= 0 && hash != GIT_HASH_UNKNOWN && hash != repo_fmt->hash_algo)
 386                 die(_("attempt to reinitialize repository with different hash"));
 387         else if (hash != GIT_HASH_UNKNOWN)
 388                 repo_fmt->hash_algo = hash;
 389         else if (env) {
 390                 int env_algo = hash_algo_by_name(env);
 391                 if (env_algo == GIT_HASH_UNKNOWN)
 392                         die(_("unknown hash algorithm '%s'"), env);
 393                 repo_fmt->hash_algo = env_algo;
 394         }
 395 }
 396
 397 int init_db(const char *git_dir, const char *real_git_dir,
 398             const char *template_dir, int hash, const char *initial_branch,
 399             unsigned int flags)
 400 {
 401         int reinit;
 402         int exist_ok = flags & INIT_DB_EXIST_OK;
 403         char *original_git_dir = real_pathdup(git_dir, 1);
 404         struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
 405
 406         if (real_git_dir) {
 407                 struct stat st;
 408
 409                 if (!exist_ok && !stat(git_dir, &st))
 410                         die(_("%s already exists"), git_dir);
 411
 412                 if (!exist_ok && !stat(real_git_dir, &st))
 413                         die(_("%s already exists"), real_git_dir);
 414
 415                 set_git_dir(real_git_dir, 1);
 416                 git_dir = get_git_dir();
 417                 separate_git_dir(git_dir, original_git_dir);
 418         }
 419         else {
 420                 set_git_dir(git_dir, 1);
 421                 git_dir = get_git_dir();
 422         }
 423         startup_info->have_repository = 1;
 424
 425         /* Just look for `core.hidedotfiles` */
 426         git_config(git_init_db_config, NULL);
 427
 428         safe_create_dir(git_dir, 0);
 429
 430         init_is_bare_repository = is_bare_repository();
 431
 432         /* Check to see if the repository version is right.
 433          * Note that a newly created repository does not have
 434          * config file, so this will not fail.  What we are catching
 435          * is an attempt to reinitialize new repository with an old tool.
 436          */
 437         check_repository_format(&repo_fmt);
 438
 439         validate_hash_algorithm(&repo_fmt, hash);
 440
 441         reinit = create_default_files(template_dir, original_git_dir,
 442                                       initial_branch, &repo_fmt,
 443                                       flags & INIT_DB_QUIET);
 444         if (reinit && initial_branch)
 445                 warning(_("re-init: ignored --initial-branch=%s"),
 446                         initial_branch);
 447
 448         create_object_directory();
 449
 450         if (get_shared_repository()) {
 451                 char buf[10];
 452                 /* We do not spell "group" and such, so that
 453                  * the configuration can be read by older version
 454                  * of git. Note, we use octal numbers for new share modes,
 455                  * and compatibility values for PERM_GROUP and
 456                  * PERM_EVERYBODY.
 457                  */
 458                 if (get_shared_repository() < 0)
 459                         /* force to the mode value */
 460                         xsnprintf(buf, sizeof(buf), "0%o", -get_shared_repository());
 461                 else if (get_shared_repository() == PERM_GROUP)
 462                         xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_GROUP);
 463                 else if (get_shared_repository() == PERM_EVERYBODY)
 464                         xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_EVERYBODY);
 465                 else
 466                         BUG("invalid value for shared_repository");
 467                 git_config_set("core.sharedrepository", buf);
 468                 git_config_set("receive.denyNonFastforwards", "true");
 469         }
 470
 471         if (!(flags & INIT_DB_QUIET)) {
 472                 int len = strlen(git_dir);
 473
 474                 if (reinit)
 475                         printf(get_shared_repository()
 476                                ? _("Reinitialized existing shared Git repository in %s%s\n")
 477                                : _("Reinitialized existing Git repository in %s%s\n"),
 478                                git_dir, len && git_dir[len-1] != '/' ? "/" : "");
 479                 else
 480                         printf(get_shared_repository()
 481                                ? _("Initialized empty shared Git repository in %s%s\n")
 482                                : _("Initialized empty Git repository in %s%s\n"),
 483                                git_dir, len && git_dir[len-1] != '/' ? "/" : "");
 484         }
 485
 486         free(original_git_dir);
 487         return 0;
 488 }
 489
 490 static int guess_repository_type(const char *git_dir)
 491 {
 492         const char *slash;
 493         char *cwd;
 494         int cwd_is_git_dir;
 495
 496         /*
 497          * "GIT_DIR=. git init" is always bare.
 498          * "GIT_DIR=`pwd` git init" too.
 499          */
 500         if (!strcmp(".", git_dir))
 501                 return 1;
 502         cwd = xgetcwd();
 503         cwd_is_git_dir = !strcmp(git_dir, cwd);
 504         free(cwd);
 505         if (cwd_is_git_dir)
 506                 return 1;
 507         /*
 508          * "GIT_DIR=.git or GIT_DIR=something/.git is usually not.
 509          */
 510         if (!strcmp(git_dir, ".git"))
 511                 return 0;
 512         slash = strrchr(git_dir, '/');
 513         if (slash && !strcmp(slash, "/.git"))
 514                 return 0;
 515
 516         /*
 517          * Otherwise it is often bare.  At this point
 518          * we are just guessing.
 519          */
 520         return 1;
 521 }
 522
 523 static int shared_callback(const struct option *opt, const char *arg, int unset)
 524 {
 525         BUG_ON_OPT_NEG(unset);
 526         *((int *) opt->value) = (arg) ? git_config_perm("arg", arg) : PERM_GROUP;
 527         return 0;
 528 }
 529
 530 static const char *const init_db_usage[] = {
 531         N_("git init [-q | --quiet] [--bare] [--template=<template-directory>] [--shared[=<permissions>]] [<directory>]"),
 532         NULL
 533 };
 534
 535 /*
 536  * If you want to, you can share the DB area with any number of branches.
 537  * That has advantages: you can save space by sharing all the SHA1 objects.
 538  * On the other hand, it might just make lookup slower and messier. You
 539  * be the judge.  The default case is to have one DB per managed directory.
 540  */
 541 int cmd_init_db(int argc, const char **argv, const char *prefix)
 542 {
 543         const char *git_dir;
 544         const char *real_git_dir = NULL;
 545         const char *work_tree;
 546         const char *template_dir = NULL;
 547         unsigned int flags = 0;
 548         const char *object_format = NULL;
 549         const char *initial_branch = NULL;
 550         int hash_algo = GIT_HASH_UNKNOWN;
 551         const struct option init_db_options[] = {
 552                 OPT_STRING(0, "template", &template_dir, N_("template-directory"),
 553                                 N_("directory from which templates will be used")),
 554                 OPT_SET_INT(0, "bare", &is_bare_repository_cfg,
 555                                 N_("create a bare repository"), 1),
 556                 { OPTION_CALLBACK, 0, "shared", &init_shared_repository,
 557                         N_("permissions"),
 558                         N_("specify that the git repository is to be shared amongst several users"),
 559                         PARSE_OPT_OPTARG | PARSE_OPT_NONEG, shared_callback, 0},
 560                 OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
 561                 OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
 562                            N_("separate git dir from working tree")),
 563                 OPT_STRING('b', "initial-branch", &initial_branch, N_("name"),
 564                            N_("override the name of the initial branch")),
 565                 OPT_STRING(0, "object-format", &object_format, N_("hash"),
 566                            N_("specify the hash algorithm to use")),
 567                 OPT_END()
 568         };
 569
 570         argc = parse_options(argc, argv, prefix, init_db_options, init_db_usage, 0);
 571
 572         if (real_git_dir && is_bare_repository_cfg == 1)
 573                 die(_("--separate-git-dir and --bare are mutually exclusive"));
 574
 575         if (real_git_dir && !is_absolute_path(real_git_dir))
 576                 real_git_dir = real_pathdup(real_git_dir, 1);
 577
 578         if (template_dir && *template_dir && !is_absolute_path(template_dir))
 579                 template_dir = absolute_pathdup(template_dir);
 580
 581         if (argc == 1) {
 582                 int mkdir_tried = 0;
 583         retry:
 584                 if (chdir(argv[0]) < 0) {
 585                         if (!mkdir_tried) {
 586                                 int saved;
 587                                 /*
 588                                  * At this point we haven't read any configuration,
 589                                  * and we know shared_repository should always be 0;
 590                                  * but just in case we play safe.
 591                                  */
 592                                 saved = get_shared_repository();
 593                                 set_shared_repository(0);
 594                                 switch (safe_create_leading_directories_const(argv[0])) {
 595                                 case SCLD_OK:
 596                                 case SCLD_PERMS:
 597                                         break;
 598                                 case SCLD_EXISTS:
 599                                         errno = EEXIST;
 600                                         /* fallthru */
 601                                 default:
 602                                         die_errno(_("cannot mkdir %s"), argv[0]);
 603                                         break;
 604                                 }
 605                                 set_shared_repository(saved);
 606                                 if (mkdir(argv[0], 0777) < 0)
 607                                         die_errno(_("cannot mkdir %s"), argv[0]);
 608                                 mkdir_tried = 1;
 609                                 goto retry;
 610                         }
 611                         die_errno(_("cannot chdir to %s"), argv[0]);
 612                 }
 613         } else if (0 < argc) {
 614                 usage(init_db_usage[0]);
 615         }
 616         if (is_bare_repository_cfg == 1) {
 617                 char *cwd = xgetcwd();
 618                 setenv(GIT_DIR_ENVIRONMENT, cwd, argc > 0);
 619                 free(cwd);
 620         }
 621
 622         if (object_format) {
 623                 hash_algo = hash_algo_by_name(object_format);
 624                 if (hash_algo == GIT_HASH_UNKNOWN)
 625                         die(_("unknown hash algorithm '%s'"), object_format);
 626         }
 627
 628         if (init_shared_repository != -1)
 629                 set_shared_repository(init_shared_repository);
 630
 631         /*
 632          * GIT_WORK_TREE makes sense only in conjunction with GIT_DIR
 633          * without --bare.  Catch the error early.
 634          */
 635         git_dir = xstrdup_or_null(getenv(GIT_DIR_ENVIRONMENT));
 636         work_tree = xstrdup_or_null(getenv(GIT_WORK_TREE_ENVIRONMENT));
 637         if ((!git_dir || is_bare_repository_cfg == 1) && work_tree)
 638                 die(_("%s (or --work-tree=<directory>) not allowed without "
 639                           "specifying %s (or --git-dir=<directory>)"),
 640                     GIT_WORK_TREE_ENVIRONMENT,
 641                     GIT_DIR_ENVIRONMENT);
 642
 643         /*
 644          * Set up the default .git directory contents
 645          */
 646         if (!git_dir)
 647                 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
 648
 649         /*
 650          * When --separate-git-dir is used inside a linked worktree, take
 651          * care to ensure that the common .git/ directory is relocated, not
 652          * the worktree-specific .git/worktrees/<id>/ directory.
 653          */
 654         if (real_git_dir) {
 655                 int err;
 656                 const char *p;
 657                 struct strbuf sb = STRBUF_INIT;
 658
 659                 p = read_gitfile_gently(git_dir, &err);
 660                 if (p && get_common_dir(&sb, p)) {
 661                         struct strbuf mainwt = STRBUF_INIT;
 662
 663                         strbuf_addbuf(&mainwt, &sb);
 664                         strbuf_strip_suffix(&mainwt, "/.git");
 665                         if (chdir(mainwt.buf) < 0)
 666                                 die_errno(_("cannot chdir to %s"), mainwt.buf);
 667                         strbuf_release(&mainwt);
 668                         git_dir = strbuf_detach(&sb, NULL);
 669                 }
 670                 strbuf_release(&sb);
 671         }
 672
 673         if (is_bare_repository_cfg < 0)
 674                 is_bare_repository_cfg = guess_repository_type(git_dir);
 675
 676         if (!is_bare_repository_cfg) {
 677                 const char *git_dir_parent = strrchr(git_dir, '/');
 678                 if (git_dir_parent) {
 679                         char *rel = xstrndup(git_dir, git_dir_parent - git_dir);
 680                         git_work_tree_cfg = real_pathdup(rel, 1);
 681                         free(rel);
 682                 }
 683                 if (!git_work_tree_cfg)
 684                         git_work_tree_cfg = xgetcwd();
 685                 if (work_tree)
 686                         set_git_work_tree(work_tree);
 687                 else
 688                         set_git_work_tree(git_work_tree_cfg);
 689                 if (access(get_git_work_tree(), X_OK))
 690                         die_errno (_("Cannot access work tree '%s'"),
 691                                    get_git_work_tree());
 692         }
 693         else {
 694                 if (real_git_dir)
 695                         die(_("--separate-git-dir incompatible with bare repository"));
 696                 if (work_tree)
 697                         set_git_work_tree(work_tree);
 698         }
 699
 700         UNLEAK(real_git_dir);
 701         UNLEAK(git_dir);
 702         UNLEAK(work_tree);
 703
 704         flags |= INIT_DB_EXIST_OK;
 705         return init_db(git_dir, real_git_dir, template_dir, hash_algo,
 706                        initial_branch, flags);
 707 }