path.c

   1 /*
   2  * Utilities for paths and pathnames
   3  */
   4 #include "cache.h"
   5 #include "repository.h"
   6 #include "strbuf.h"
   7 #include "string-list.h"
   8 #include "dir.h"
   9 #include "worktree.h"
  10 #include "submodule-config.h"
  11 #include "path.h"
  12 #include "packfile.h"
  13 #include "object-store.h"
  14
  15 static int get_st_mode_bits(const char *path, int *mode)
  16 {
  17         struct stat st;
  18         if (lstat(path, &st) < 0)
  19                 return -1;
  20         *mode = st.st_mode;
  21         return 0;
  22 }
  23
  24 static char bad_path[] = "/bad-path/";
  25
  26 static struct strbuf *get_pathname(void)
  27 {
  28         static struct strbuf pathname_array[4] = {
  29                 STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
  30         };
  31         static int index;
  32         struct strbuf *sb = &pathname_array[index];
  33         index = (index + 1) % ARRAY_SIZE(pathname_array);
  34         strbuf_reset(sb);
  35         return sb;
  36 }
  37
  38 static const char *cleanup_path(const char *path)
  39 {
  40         /* Clean it up */
  41         if (skip_prefix(path, "./", &path)) {
  42                 while (*path == '/')
  43                         path++;
  44         }
  45         return path;
  46 }
  47
  48 static void strbuf_cleanup_path(struct strbuf *sb)
  49 {
  50         const char *path = cleanup_path(sb->buf);
  51         if (path > sb->buf)
  52                 strbuf_remove(sb, 0, path - sb->buf);
  53 }
  54
  55 char *mksnpath(char *buf, size_t n, const char *fmt, ...)
  56 {
  57         va_list args;
  58         unsigned len;
  59
  60         va_start(args, fmt);
  61         len = vsnprintf(buf, n, fmt, args);
  62         va_end(args);
  63         if (len >= n) {
  64                 strlcpy(buf, bad_path, n);
  65                 return buf;
  66         }
  67         return (char *)cleanup_path(buf);
  68 }
  69
  70 static int dir_prefix(const char *buf, const char *dir)
  71 {
  72         int len = strlen(dir);
  73         return !strncmp(buf, dir, len) &&
  74                 (is_dir_sep(buf[len]) || buf[len] == '\0');
  75 }
  76
  77 /* $buf =~ m|$dir/+$file| but without regex */
  78 static int is_dir_file(const char *buf, const char *dir, const char *file)
  79 {
  80         int len = strlen(dir);
  81         if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
  82                 return 0;
  83         while (is_dir_sep(buf[len]))
  84                 len++;
  85         return !strcmp(buf + len, file);
  86 }
  87
  88 static void replace_dir(struct strbuf *buf, int len, const char *newdir)
  89 {
  90         int newlen = strlen(newdir);
  91         int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
  92                 !is_dir_sep(newdir[newlen - 1]);
  93         if (need_sep)
  94                 len--;   /* keep one char, to be replaced with '/'  */
  95         strbuf_splice(buf, 0, len, newdir, newlen);
  96         if (need_sep)
  97                 buf->buf[newlen] = '/';
  98 }
  99
 100 struct common_dir {
 101         /* Not considered garbage for report_linked_checkout_garbage */
 102         unsigned ignore_garbage:1;
 103         unsigned is_dir:1;
 104         /* Not common even though its parent is */
 105         unsigned exclude:1;
 106         const char *dirname;
 107 };
 108
 109 static struct common_dir common_list[] = {
 110         { 0, 1, 0, "branches" },
 111         { 0, 1, 0, "common" },
 112         { 0, 1, 0, "hooks" },
 113         { 0, 1, 0, "info" },
 114         { 0, 0, 1, "info/sparse-checkout" },
 115         { 1, 1, 0, "logs" },
 116         { 1, 1, 1, "logs/HEAD" },
 117         { 0, 1, 1, "logs/refs/bisect" },
 118         { 0, 1, 0, "lost-found" },
 119         { 0, 1, 0, "objects" },
 120         { 0, 1, 0, "refs" },
 121         { 0, 1, 1, "refs/bisect" },
 122         { 0, 1, 1, "refs/worktree" },
 123         { 0, 1, 0, "remotes" },
 124         { 0, 1, 0, "worktrees" },
 125         { 0, 1, 0, "rr-cache" },
 126         { 0, 1, 0, "svn" },
 127         { 0, 0, 0, "config" },
 128         { 1, 0, 0, "gc.pid" },
 129         { 0, 0, 0, "packed-refs" },
 130         { 0, 0, 0, "shallow" },
 131         { 0, 0, 0, NULL }
 132 };
 133
 134 /*
 135  * A compressed trie.  A trie node consists of zero or more characters that
 136  * are common to all elements with this prefix, optionally followed by some
 137  * children.  If value is not NULL, the trie node is a terminal node.
 138  *
 139  * For example, consider the following set of strings:
 140  * abc
 141  * def
 142  * definite
 143  * definition
 144  *
 145  * The trie would look like:
 146  * root: len = 0, children a and d non-NULL, value = NULL.
 147  *    a: len = 2, contents = bc, value = (data for "abc")
 148  *    d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
 149  *       i: len = 3, contents = nit, children e and i non-NULL, value = NULL
 150  *           e: len = 0, children all NULL, value = (data for "definite")
 151  *           i: len = 2, contents = on, children all NULL,
 152  *              value = (data for "definition")
 153  */
 154 struct trie {
 155         struct trie *children[256];
 156         int len;
 157         char *contents;
 158         void *value;
 159 };
 160
 161 static struct trie *make_trie_node(const char *key, void *value)
 162 {
 163         struct trie *new_node = xcalloc(1, sizeof(*new_node));
 164         new_node->len = strlen(key);
 165         if (new_node->len) {
 166                 new_node->contents = xmalloc(new_node->len);
 167                 memcpy(new_node->contents, key, new_node->len);
 168         }
 169         new_node->value = value;
 170         return new_node;
 171 }
 172
 173 /*
 174  * Add a key/value pair to a trie.  The key is assumed to be \0-terminated.
 175  * If there was an existing value for this key, return it.
 176  */
 177 static void *add_to_trie(struct trie *root, const char *key, void *value)
 178 {
 179         struct trie *child;
 180         void *old;
 181         int i;
 182
 183         if (!*key) {
 184                 /* we have reached the end of the key */
 185                 old = root->value;
 186                 root->value = value;
 187                 return old;
 188         }
 189
 190         for (i = 0; i < root->len; i++) {
 191                 if (root->contents[i] == key[i])
 192                         continue;
 193
 194                 /*
 195                  * Split this node: child will contain this node's
 196                  * existing children.
 197                  */
 198                 child = xmalloc(sizeof(*child));
 199                 memcpy(child->children, root->children, sizeof(root->children));
 200
 201                 child->len = root->len - i - 1;
 202                 if (child->len) {
 203                         child->contents = xstrndup(root->contents + i + 1,
 204                                                    child->len);
 205                 }
 206                 child->value = root->value;
 207                 root->value = NULL;
 208                 root->len = i;
 209
 210                 memset(root->children, 0, sizeof(root->children));
 211                 root->children[(unsigned char)root->contents[i]] = child;
 212
 213                 /* This is the newly-added child. */
 214                 root->children[(unsigned char)key[i]] =
 215                         make_trie_node(key + i + 1, value);
 216                 return NULL;
 217         }
 218
 219         /* We have matched the entire compressed section */
 220         if (key[i]) {
 221                 child = root->children[(unsigned char)key[root->len]];
 222                 if (child) {
 223                         return add_to_trie(child, key + root->len + 1, value);
 224                 } else {
 225                         child = make_trie_node(key + root->len + 1, value);
 226                         root->children[(unsigned char)key[root->len]] = child;
 227                         return NULL;
 228                 }
 229         }
 230
 231         old = root->value;
 232         root->value = value;
 233         return old;
 234 }
 235
 236 typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
 237
 238 /*
 239  * Search a trie for some key.  Find the longest /-or-\0-terminated
 240  * prefix of the key for which the trie contains a value.  Call fn
 241  * with the unmatched portion of the key and the found value, and
 242  * return its return value.  If there is no such prefix, return -1.
 243  *
 244  * The key is partially normalized: consecutive slashes are skipped.
 245  *
 246  * For example, consider the trie containing only [refs,
 247  * refs/worktree] (both with values).
 248  *
 249  * | key             | unmatched  | val from node | return value |
 250  * |-----------------|------------|---------------|--------------|
 251  * | a               | not called | n/a           | -1           |
 252  * | refs            | \0         | refs          | as per fn    |
 253  * | refs/           | /          | refs          | as per fn    |
 254  * | refs/w          | /w         | refs          | as per fn    |
 255  * | refs/worktree   | \0         | refs/worktree | as per fn    |
 256  * | refs/worktree/  | /          | refs/worktree | as per fn    |
 257  * | refs/worktree/a | /a         | refs/worktree | as per fn    |
 258  * |-----------------|------------|---------------|--------------|
 259  *
 260  */
 261 static int trie_find(struct trie *root, const char *key, match_fn fn,
 262                      void *baton)
 263 {
 264         int i;
 265         int result;
 266         struct trie *child;
 267
 268         if (!*key) {
 269                 /* we have reached the end of the key */
 270                 if (root->value && !root->len)
 271                         return fn(key, root->value, baton);
 272                 else
 273                         return -1;
 274         }
 275
 276         for (i = 0; i < root->len; i++) {
 277                 /* Partial path normalization: skip consecutive slashes. */
 278                 if (key[i] == '/' && key[i+1] == '/') {
 279                         key++;
 280                         continue;
 281                 }
 282                 if (root->contents[i] != key[i])
 283                         return -1;
 284         }
 285
 286         /* Matched the entire compressed section */
 287         key += i;
 288         if (!*key)
 289                 /* End of key */
 290                 return fn(key, root->value, baton);
 291
 292         /* Partial path normalization: skip consecutive slashes */
 293         while (key[0] == '/' && key[1] == '/')
 294                 key++;
 295
 296         child = root->children[(unsigned char)*key];
 297         if (child)
 298                 result = trie_find(child, key + 1, fn, baton);
 299         else
 300                 result = -1;
 301
 302         if (result >= 0 || (*key != '/' && *key != 0))
 303                 return result;
 304         if (root->value)
 305                 return fn(key, root->value, baton);
 306         else
 307                 return -1;
 308 }
 309
 310 static struct trie common_trie;
 311 static int common_trie_done_setup;
 312
 313 static void init_common_trie(void)
 314 {
 315         struct common_dir *p;
 316
 317         if (common_trie_done_setup)
 318                 return;
 319
 320         for (p = common_list; p->dirname; p++)
 321                 add_to_trie(&common_trie, p->dirname, p);
 322
 323         common_trie_done_setup = 1;
 324 }
 325
 326 /*
 327  * Helper function for update_common_dir: returns 1 if the dir
 328  * prefix is common.
 329  */
 330 static int check_common(const char *unmatched, void *value, void *baton)
 331 {
 332         struct common_dir *dir = value;
 333
 334         if (!dir)
 335                 return 0;
 336
 337         if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
 338                 return !dir->exclude;
 339
 340         if (!dir->is_dir && unmatched[0] == 0)
 341                 return !dir->exclude;
 342
 343         return 0;
 344 }
 345
 346 static void update_common_dir(struct strbuf *buf, int git_dir_len,
 347                               const char *common_dir)
 348 {
 349         char *base = buf->buf + git_dir_len;
 350         init_common_trie();
 351         if (trie_find(&common_trie, base, check_common, NULL) > 0)
 352                 replace_dir(buf, git_dir_len, common_dir);
 353 }
 354
 355 void report_linked_checkout_garbage(void)
 356 {
 357         struct strbuf sb = STRBUF_INIT;
 358         const struct common_dir *p;
 359         int len;
 360
 361         if (!the_repository->different_commondir)
 362                 return;
 363         strbuf_addf(&sb, "%s/", get_git_dir());
 364         len = sb.len;
 365         for (p = common_list; p->dirname; p++) {
 366                 const char *path = p->dirname;
 367                 if (p->ignore_garbage)
 368                         continue;
 369                 strbuf_setlen(&sb, len);
 370                 strbuf_addstr(&sb, path);
 371                 if (file_exists(sb.buf))
 372                         report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
 373         }
 374         strbuf_release(&sb);
 375 }
 376
 377 static void adjust_git_path(const struct repository *repo,
 378                             struct strbuf *buf, int git_dir_len)
 379 {
 380         const char *base = buf->buf + git_dir_len;
 381         if (is_dir_file(base, "info", "grafts"))
 382                 strbuf_splice(buf, 0, buf->len,
 383                               repo->graft_file, strlen(repo->graft_file));
 384         else if (!strcmp(base, "index"))
 385                 strbuf_splice(buf, 0, buf->len,
 386                               repo->index_file, strlen(repo->index_file));
 387         else if (dir_prefix(base, "objects"))
 388                 replace_dir(buf, git_dir_len + 7, repo->objects->odb->path);
 389         else if (git_hooks_path && dir_prefix(base, "hooks"))
 390                 replace_dir(buf, git_dir_len + 5, git_hooks_path);
 391         else if (repo->different_commondir)
 392                 update_common_dir(buf, git_dir_len, repo->commondir);
 393 }
 394
 395 static void strbuf_worktree_gitdir(struct strbuf *buf,
 396                                    const struct repository *repo,
 397                                    const struct worktree *wt)
 398 {
 399         if (!wt)
 400                 strbuf_addstr(buf, repo->gitdir);
 401         else if (!wt->id)
 402                 strbuf_addstr(buf, repo->commondir);
 403         else
 404                 strbuf_git_common_path(buf, repo, "worktrees/%s", wt->id);
 405 }
 406
 407 static void do_git_path(const struct repository *repo,
 408                         const struct worktree *wt, struct strbuf *buf,
 409                         const char *fmt, va_list args)
 410 {
 411         int gitdir_len;
 412         strbuf_worktree_gitdir(buf, repo, wt);
 413         if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 414                 strbuf_addch(buf, '/');
 415         gitdir_len = buf->len;
 416         strbuf_vaddf(buf, fmt, args);
 417         if (!wt)
 418                 adjust_git_path(repo, buf, gitdir_len);
 419         strbuf_cleanup_path(buf);
 420 }
 421
 422 char *repo_git_path(const struct repository *repo,
 423                     const char *fmt, ...)
 424 {
 425         struct strbuf path = STRBUF_INIT;
 426         va_list args;
 427         va_start(args, fmt);
 428         do_git_path(repo, NULL, &path, fmt, args);
 429         va_end(args);
 430         return strbuf_detach(&path, NULL);
 431 }
 432
 433 void strbuf_repo_git_path(struct strbuf *sb,
 434                           const struct repository *repo,
 435                           const char *fmt, ...)
 436 {
 437         va_list args;
 438         va_start(args, fmt);
 439         do_git_path(repo, NULL, sb, fmt, args);
 440         va_end(args);
 441 }
 442
 443 char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
 444 {
 445         va_list args;
 446         strbuf_reset(buf);
 447         va_start(args, fmt);
 448         do_git_path(the_repository, NULL, buf, fmt, args);
 449         va_end(args);
 450         return buf->buf;
 451 }
 452
 453 void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 454 {
 455         va_list args;
 456         va_start(args, fmt);
 457         do_git_path(the_repository, NULL, sb, fmt, args);
 458         va_end(args);
 459 }
 460
 461 const char *git_path(const char *fmt, ...)
 462 {
 463         struct strbuf *pathname = get_pathname();
 464         va_list args;
 465         va_start(args, fmt);
 466         do_git_path(the_repository, NULL, pathname, fmt, args);
 467         va_end(args);
 468         return pathname->buf;
 469 }
 470
 471 char *git_pathdup(const char *fmt, ...)
 472 {
 473         struct strbuf path = STRBUF_INIT;
 474         va_list args;
 475         va_start(args, fmt);
 476         do_git_path(the_repository, NULL, &path, fmt, args);
 477         va_end(args);
 478         return strbuf_detach(&path, NULL);
 479 }
 480
 481 char *mkpathdup(const char *fmt, ...)
 482 {
 483         struct strbuf sb = STRBUF_INIT;
 484         va_list args;
 485         va_start(args, fmt);
 486         strbuf_vaddf(&sb, fmt, args);
 487         va_end(args);
 488         strbuf_cleanup_path(&sb);
 489         return strbuf_detach(&sb, NULL);
 490 }
 491
 492 const char *mkpath(const char *fmt, ...)
 493 {
 494         va_list args;
 495         struct strbuf *pathname = get_pathname();
 496         va_start(args, fmt);
 497         strbuf_vaddf(pathname, fmt, args);
 498         va_end(args);
 499         return cleanup_path(pathname->buf);
 500 }
 501
 502 const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 503 {
 504         struct strbuf *pathname = get_pathname();
 505         va_list args;
 506         va_start(args, fmt);
 507         do_git_path(the_repository, wt, pathname, fmt, args);
 508         va_end(args);
 509         return pathname->buf;
 510 }
 511
 512 static void do_worktree_path(const struct repository *repo,
 513                              struct strbuf *buf,
 514                              const char *fmt, va_list args)
 515 {
 516         strbuf_addstr(buf, repo->worktree);
 517         if(buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 518                 strbuf_addch(buf, '/');
 519
 520         strbuf_vaddf(buf, fmt, args);
 521         strbuf_cleanup_path(buf);
 522 }
 523
 524 char *repo_worktree_path(const struct repository *repo, const char *fmt, ...)
 525 {
 526         struct strbuf path = STRBUF_INIT;
 527         va_list args;
 528
 529         if (!repo->worktree)
 530                 return NULL;
 531
 532         va_start(args, fmt);
 533         do_worktree_path(repo, &path, fmt, args);
 534         va_end(args);
 535
 536         return strbuf_detach(&path, NULL);
 537 }
 538
 539 void strbuf_repo_worktree_path(struct strbuf *sb,
 540                                const struct repository *repo,
 541                                const char *fmt, ...)
 542 {
 543         va_list args;
 544
 545         if (!repo->worktree)
 546                 return;
 547
 548         va_start(args, fmt);
 549         do_worktree_path(repo, sb, fmt, args);
 550         va_end(args);
 551 }
 552
 553 /* Returns 0 on success, negative on failure. */
 554 static int do_submodule_path(struct strbuf *buf, const char *path,
 555                              const char *fmt, va_list args)
 556 {
 557         struct strbuf git_submodule_common_dir = STRBUF_INIT;
 558         struct strbuf git_submodule_dir = STRBUF_INIT;
 559         int ret;
 560
 561         ret = submodule_to_gitdir(&git_submodule_dir, path);
 562         if (ret)
 563                 goto cleanup;
 564
 565         strbuf_complete(&git_submodule_dir, '/');
 566         strbuf_addbuf(buf, &git_submodule_dir);
 567         strbuf_vaddf(buf, fmt, args);
 568
 569         if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
 570                 update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
 571
 572         strbuf_cleanup_path(buf);
 573
 574 cleanup:
 575         strbuf_release(&git_submodule_dir);
 576         strbuf_release(&git_submodule_common_dir);
 577         return ret;
 578 }
 579
 580 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
 581 {
 582         int err;
 583         va_list args;
 584         struct strbuf buf = STRBUF_INIT;
 585         va_start(args, fmt);
 586         err = do_submodule_path(&buf, path, fmt, args);
 587         va_end(args);
 588         if (err) {
 589                 strbuf_release(&buf);
 590                 return NULL;
 591         }
 592         return strbuf_detach(&buf, NULL);
 593 }
 594
 595 int strbuf_git_path_submodule(struct strbuf *buf, const char *path,
 596                               const char *fmt, ...)
 597 {
 598         int err;
 599         va_list args;
 600         va_start(args, fmt);
 601         err = do_submodule_path(buf, path, fmt, args);
 602         va_end(args);
 603
 604         return err;
 605 }
 606
 607 static void do_git_common_path(const struct repository *repo,
 608                                struct strbuf *buf,
 609                                const char *fmt,
 610                                va_list args)
 611 {
 612         strbuf_addstr(buf, repo->commondir);
 613         if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 614                 strbuf_addch(buf, '/');
 615         strbuf_vaddf(buf, fmt, args);
 616         strbuf_cleanup_path(buf);
 617 }
 618
 619 const char *git_common_path(const char *fmt, ...)
 620 {
 621         struct strbuf *pathname = get_pathname();
 622         va_list args;
 623         va_start(args, fmt);
 624         do_git_common_path(the_repository, pathname, fmt, args);
 625         va_end(args);
 626         return pathname->buf;
 627 }
 628
 629 void strbuf_git_common_path(struct strbuf *sb,
 630                             const struct repository *repo,
 631                             const char *fmt, ...)
 632 {
 633         va_list args;
 634         va_start(args, fmt);
 635         do_git_common_path(repo, sb, fmt, args);
 636         va_end(args);
 637 }
 638
 639 int validate_headref(const char *path)
 640 {
 641         struct stat st;
 642         char buffer[256];
 643         const char *refname;
 644         struct object_id oid;
 645         int fd;
 646         ssize_t len;
 647
 648         if (lstat(path, &st) < 0)
 649                 return -1;
 650
 651         /* Make sure it is a "refs/.." symlink */
 652         if (S_ISLNK(st.st_mode)) {
 653                 len = readlink(path, buffer, sizeof(buffer)-1);
 654                 if (len >= 5 && !memcmp("refs/", buffer, 5))
 655                         return 0;
 656                 return -1;
 657         }
 658
 659         /*
 660          * Anything else, just open it and try to see if it is a symbolic ref.
 661          */
 662         fd = open(path, O_RDONLY);
 663         if (fd < 0)
 664                 return -1;
 665         len = read_in_full(fd, buffer, sizeof(buffer)-1);
 666         close(fd);
 667
 668         if (len < 0)
 669                 return -1;
 670         buffer[len] = '\0';
 671
 672         /*
 673          * Is it a symbolic ref?
 674          */
 675         if (skip_prefix(buffer, "ref:", &refname)) {
 676                 while (isspace(*refname))
 677                         refname++;
 678                 if (starts_with(refname, "refs/"))
 679                         return 0;
 680         }
 681
 682         /*
 683          * Is this a detached HEAD?
 684          */
 685         if (!get_oid_hex(buffer, &oid))
 686                 return 0;
 687
 688         return -1;
 689 }
 690
 691 static struct passwd *getpw_str(const char *username, size_t len)
 692 {
 693         struct passwd *pw;
 694         char *username_z = xmemdupz(username, len);
 695         pw = getpwnam(username_z);
 696         free(username_z);
 697         return pw;
 698 }
 699
 700 /*
 701  * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
 702  * then it is a newly allocated string. Returns NULL on getpw failure or
 703  * if path is NULL.
 704  *
 705  * If real_home is true, real_path($HOME) is used in the expansion.
 706  */
 707 char *expand_user_path(const char *path, int real_home)
 708 {
 709         struct strbuf user_path = STRBUF_INIT;
 710         const char *to_copy = path;
 711
 712         if (path == NULL)
 713                 goto return_null;
 714         if (path[0] == '~') {
 715                 const char *first_slash = strchrnul(path, '/');
 716                 const char *username = path + 1;
 717                 size_t username_len = first_slash - username;
 718                 if (username_len == 0) {
 719                         const char *home = getenv("HOME");
 720                         if (!home)
 721                                 goto return_null;
 722                         if (real_home)
 723                                 strbuf_add_real_path(&user_path, home);
 724                         else
 725                                 strbuf_addstr(&user_path, home);
 726 #ifdef GIT_WINDOWS_NATIVE
 727                         convert_slashes(user_path.buf);
 728 #endif
 729                 } else {
 730                         struct passwd *pw = getpw_str(username, username_len);
 731                         if (!pw)
 732                                 goto return_null;
 733                         strbuf_addstr(&user_path, pw->pw_dir);
 734                 }
 735                 to_copy = first_slash;
 736         }
 737         strbuf_addstr(&user_path, to_copy);
 738         return strbuf_detach(&user_path, NULL);
 739 return_null:
 740         strbuf_release(&user_path);
 741         return NULL;
 742 }
 743
 744 /*
 745  * First, one directory to try is determined by the following algorithm.
 746  *
 747  * (0) If "strict" is given, the path is used as given and no DWIM is
 748  *     done. Otherwise:
 749  * (1) "~/path" to mean path under the running user's home directory;
 750  * (2) "~user/path" to mean path under named user's home directory;
 751  * (3) "relative/path" to mean cwd relative directory; or
 752  * (4) "/absolute/path" to mean absolute directory.
 753  *
 754  * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
 755  * in this order. We select the first one that is a valid git repository, and
 756  * chdir() to it. If none match, or we fail to chdir, we return NULL.
 757  *
 758  * If all goes well, we return the directory we used to chdir() (but
 759  * before ~user is expanded), avoiding getcwd() resolving symbolic
 760  * links.  User relative paths are also returned as they are given,
 761  * except DWIM suffixing.
 762  */
 763 const char *enter_repo(const char *path, int strict)
 764 {
 765         static struct strbuf validated_path = STRBUF_INIT;
 766         static struct strbuf used_path = STRBUF_INIT;
 767
 768         if (!path)
 769                 return NULL;
 770
 771         if (!strict) {
 772                 static const char *suffix[] = {
 773                         "/.git", "", ".git/.git", ".git", NULL,
 774                 };
 775                 const char *gitfile;
 776                 int len = strlen(path);
 777                 int i;
 778                 while ((1 < len) && (path[len-1] == '/'))
 779                         len--;
 780
 781                 /*
 782                  * We can handle arbitrary-sized buffers, but this remains as a
 783                  * sanity check on untrusted input.
 784                  */
 785                 if (PATH_MAX <= len)
 786                         return NULL;
 787
 788                 strbuf_reset(&used_path);
 789                 strbuf_reset(&validated_path);
 790                 strbuf_add(&used_path, path, len);
 791                 strbuf_add(&validated_path, path, len);
 792
 793                 if (used_path.buf[0] == '~') {
 794                         char *newpath = expand_user_path(used_path.buf, 0);
 795                         if (!newpath)
 796                                 return NULL;
 797                         strbuf_attach(&used_path, newpath, strlen(newpath),
 798                                       strlen(newpath));
 799                 }
 800                 for (i = 0; suffix[i]; i++) {
 801                         struct stat st;
 802                         size_t baselen = used_path.len;
 803                         strbuf_addstr(&used_path, suffix[i]);
 804                         if (!stat(used_path.buf, &st) &&
 805                             (S_ISREG(st.st_mode) ||
 806                             (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
 807                                 strbuf_addstr(&validated_path, suffix[i]);
 808                                 break;
 809                         }
 810                         strbuf_setlen(&used_path, baselen);
 811                 }
 812                 if (!suffix[i])
 813                         return NULL;
 814                 gitfile = read_gitfile(used_path.buf);
 815                 if (gitfile) {
 816                         strbuf_reset(&used_path);
 817                         strbuf_addstr(&used_path, gitfile);
 818                 }
 819                 if (chdir(used_path.buf))
 820                         return NULL;
 821                 path = validated_path.buf;
 822         }
 823         else {
 824                 const char *gitfile = read_gitfile(path);
 825                 if (gitfile)
 826                         path = gitfile;
 827                 if (chdir(path))
 828                         return NULL;
 829         }
 830
 831         if (is_git_directory(".")) {
 832                 set_git_dir(".");
 833                 check_repository_format();
 834                 return path;
 835         }
 836
 837         return NULL;
 838 }
 839
 840 static int calc_shared_perm(int mode)
 841 {
 842         int tweak;
 843
 844         if (get_shared_repository() < 0)
 845                 tweak = -get_shared_repository();
 846         else
 847                 tweak = get_shared_repository();
 848
 849         if (!(mode & S_IWUSR))
 850                 tweak &= ~0222;
 851         if (mode & S_IXUSR)
 852                 /* Copy read bits to execute bits */
 853                 tweak |= (tweak & 0444) >> 2;
 854         if (get_shared_repository() < 0)
 855                 mode = (mode & ~0777) | tweak;
 856         else
 857                 mode |= tweak;
 858
 859         return mode;
 860 }
 861
 862
 863 int adjust_shared_perm(const char *path)
 864 {
 865         int old_mode, new_mode;
 866
 867         if (!get_shared_repository())
 868                 return 0;
 869         if (get_st_mode_bits(path, &old_mode) < 0)
 870                 return -1;
 871
 872         new_mode = calc_shared_perm(old_mode);
 873         if (S_ISDIR(old_mode)) {
 874                 /* Copy read bits to execute bits */
 875                 new_mode |= (new_mode & 0444) >> 2;
 876                 new_mode |= FORCE_DIR_SET_GID;
 877         }
 878
 879         if (((old_mode ^ new_mode) & ~S_IFMT) &&
 880                         chmod(path, (new_mode & ~S_IFMT)) < 0)
 881                 return -2;
 882         return 0;
 883 }
 884
 885 void safe_create_dir(const char *dir, int share)
 886 {
 887         if (mkdir(dir, 0777) < 0) {
 888                 if (errno != EEXIST) {
 889                         perror(dir);
 890                         exit(1);
 891                 }
 892         }
 893         else if (share && adjust_shared_perm(dir))
 894                 die(_("Could not make %s writable by group"), dir);
 895 }
 896
 897 static int have_same_root(const char *path1, const char *path2)
 898 {
 899         int is_abs1, is_abs2;
 900
 901         is_abs1 = is_absolute_path(path1);
 902         is_abs2 = is_absolute_path(path2);
 903         return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
 904                (!is_abs1 && !is_abs2);
 905 }
 906
 907 /*
 908  * Give path as relative to prefix.
 909  *
 910  * The strbuf may or may not be used, so do not assume it contains the
 911  * returned path.
 912  */
 913 const char *relative_path(const char *in, const char *prefix,
 914                           struct strbuf *sb)
 915 {
 916         int in_len = in ? strlen(in) : 0;
 917         int prefix_len = prefix ? strlen(prefix) : 0;
 918         int in_off = 0;
 919         int prefix_off = 0;
 920         int i = 0, j = 0;
 921
 922         if (!in_len)
 923                 return "./";
 924         else if (!prefix_len)
 925                 return in;
 926
 927         if (have_same_root(in, prefix))
 928                 /* bypass dos_drive, for "c:" is identical to "C:" */
 929                 i = j = has_dos_drive_prefix(in);
 930         else {
 931                 return in;
 932         }
 933
 934         while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
 935                 if (is_dir_sep(prefix[i])) {
 936                         while (is_dir_sep(prefix[i]))
 937                                 i++;
 938                         while (is_dir_sep(in[j]))
 939                                 j++;
 940                         prefix_off = i;
 941                         in_off = j;
 942                 } else {
 943                         i++;
 944                         j++;
 945                 }
 946         }
 947
 948         if (
 949             /* "prefix" seems like prefix of "in" */
 950             i >= prefix_len &&
 951             /*
 952              * but "/foo" is not a prefix of "/foobar"
 953              * (i.e. prefix not end with '/')
 954              */
 955             prefix_off < prefix_len) {
 956                 if (j >= in_len) {
 957                         /* in="/a/b", prefix="/a/b" */
 958                         in_off = in_len;
 959                 } else if (is_dir_sep(in[j])) {
 960                         /* in="/a/b/c", prefix="/a/b" */
 961                         while (is_dir_sep(in[j]))
 962                                 j++;
 963                         in_off = j;
 964                 } else {
 965                         /* in="/a/bbb/c", prefix="/a/b" */
 966                         i = prefix_off;
 967                 }
 968         } else if (
 969                    /* "in" is short than "prefix" */
 970                    j >= in_len &&
 971                    /* "in" not end with '/' */
 972                    in_off < in_len) {
 973                 if (is_dir_sep(prefix[i])) {
 974                         /* in="/a/b", prefix="/a/b/c/" */
 975                         while (is_dir_sep(prefix[i]))
 976                                 i++;
 977                         in_off = in_len;
 978                 }
 979         }
 980         in += in_off;
 981         in_len -= in_off;
 982
 983         if (i >= prefix_len) {
 984                 if (!in_len)
 985                         return "./";
 986                 else
 987                         return in;
 988         }
 989
 990         strbuf_reset(sb);
 991         strbuf_grow(sb, in_len);
 992
 993         while (i < prefix_len) {
 994                 if (is_dir_sep(prefix[i])) {
 995                         strbuf_addstr(sb, "../");
 996                         while (is_dir_sep(prefix[i]))
 997                                 i++;
 998                         continue;
 999                 }
1000                 i++;
1001         }
1002         if (!is_dir_sep(prefix[prefix_len - 1]))
1003                 strbuf_addstr(sb, "../");
1004
1005         strbuf_addstr(sb, in);
1006
1007         return sb->buf;
1008 }
1009
1010 /*
1011  * A simpler implementation of relative_path
1012  *
1013  * Get relative path by removing "prefix" from "in". This function
1014  * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
1015  * to increase performance when traversing the path to work_tree.
1016  */
1017 const char *remove_leading_path(const char *in, const char *prefix)
1018 {
1019         static struct strbuf buf = STRBUF_INIT;
1020         int i = 0, j = 0;
1021
1022         if (!prefix || !prefix[0])
1023                 return in;
1024         while (prefix[i]) {
1025                 if (is_dir_sep(prefix[i])) {
1026                         if (!is_dir_sep(in[j]))
1027                                 return in;
1028                         while (is_dir_sep(prefix[i]))
1029                                 i++;
1030                         while (is_dir_sep(in[j]))
1031                                 j++;
1032                         continue;
1033                 } else if (in[j] != prefix[i]) {
1034                         return in;
1035                 }
1036                 i++;
1037                 j++;
1038         }
1039         if (
1040             /* "/foo" is a prefix of "/foo" */
1041             in[j] &&
1042             /* "/foo" is not a prefix of "/foobar" */
1043             !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
1044            )
1045                 return in;
1046         while (is_dir_sep(in[j]))
1047                 j++;
1048
1049         strbuf_reset(&buf);
1050         if (!in[j])
1051                 strbuf_addstr(&buf, ".");
1052         else
1053                 strbuf_addstr(&buf, in + j);
1054         return buf.buf;
1055 }
1056
1057 /*
1058  * It is okay if dst == src, but they should not overlap otherwise.
1059  *
1060  * Performs the following normalizations on src, storing the result in dst:
1061  * - Ensures that components are separated by '/' (Windows only)
1062  * - Squashes sequences of '/' except "//server/share" on Windows
1063  * - Removes "." components.
1064  * - Removes ".." components, and the components the precede them.
1065  * Returns failure (non-zero) if a ".." component appears as first path
1066  * component anytime during the normalization. Otherwise, returns success (0).
1067  *
1068  * Note that this function is purely textual.  It does not follow symlinks,
1069  * verify the existence of the path, or make any system calls.
1070  *
1071  * prefix_len != NULL is for a specific case of prefix_pathspec():
1072  * assume that src == dst and src[0..prefix_len-1] is already
1073  * normalized, any time "../" eats up to the prefix_len part,
1074  * prefix_len is reduced. In the end prefix_len is the remaining
1075  * prefix that has not been overridden by user pathspec.
1076  *
1077  * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
1078  * For everything but the root folder itself, the normalized path should not
1079  * end with a '/', then the callers need to be fixed up accordingly.
1080  *
1081  */
1082 int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
1083 {
1084         char *dst0;
1085         const char *end;
1086
1087         /*
1088          * Copy initial part of absolute path: "/", "C:/", "//server/share/".
1089          */
1090         end = src + offset_1st_component(src);
1091         while (src < end) {
1092                 char c = *src++;
1093                 if (is_dir_sep(c))
1094                         c = '/';
1095                 *dst++ = c;
1096         }
1097         dst0 = dst;
1098
1099         while (is_dir_sep(*src))
1100                 src++;
1101
1102         for (;;) {
1103                 char c = *src;
1104
1105                 /*
1106                  * A path component that begins with . could be
1107                  * special:
1108                  * (1) "." and ends   -- ignore and terminate.
1109                  * (2) "./"           -- ignore them, eat slash and continue.
1110                  * (3) ".." and ends  -- strip one and terminate.
1111                  * (4) "../"          -- strip one, eat slash and continue.
1112                  */
1113                 if (c == '.') {
1114                         if (!src[1]) {
1115                                 /* (1) */
1116                                 src++;
1117                         } else if (is_dir_sep(src[1])) {
1118                                 /* (2) */
1119                                 src += 2;
1120                                 while (is_dir_sep(*src))
1121                                         src++;
1122                                 continue;
1123                         } else if (src[1] == '.') {
1124                                 if (!src[2]) {
1125                                         /* (3) */
1126                                         src += 2;
1127                                         goto up_one;
1128                                 } else if (is_dir_sep(src[2])) {
1129                                         /* (4) */
1130                                         src += 3;
1131                                         while (is_dir_sep(*src))
1132                                                 src++;
1133                                         goto up_one;
1134                                 }
1135                         }
1136                 }
1137
1138                 /* copy up to the next '/', and eat all '/' */
1139                 while ((c = *src++) != '\0' && !is_dir_sep(c))
1140                         *dst++ = c;
1141                 if (is_dir_sep(c)) {
1142                         *dst++ = '/';
1143                         while (is_dir_sep(c))
1144                                 c = *src++;
1145                         src--;
1146                 } else if (!c)
1147                         break;
1148                 continue;
1149
1150         up_one:
1151                 /*
1152                  * dst0..dst is prefix portion, and dst[-1] is '/';
1153                  * go up one level.
1154                  */
1155                 dst--;  /* go to trailing '/' */
1156                 if (dst <= dst0)
1157                         return -1;
1158                 /* Windows: dst[-1] cannot be backslash anymore */
1159                 while (dst0 < dst && dst[-1] != '/')
1160                         dst--;
1161                 if (prefix_len && *prefix_len > dst - dst0)
1162                         *prefix_len = dst - dst0;
1163         }
1164         *dst = '\0';
1165         return 0;
1166 }
1167
1168 int normalize_path_copy(char *dst, const char *src)
1169 {
1170         return normalize_path_copy_len(dst, src, NULL);
1171 }
1172
1173 /*
1174  * path = Canonical absolute path
1175  * prefixes = string_list containing normalized, absolute paths without
1176  * trailing slashes (except for the root directory, which is denoted by "/").
1177  *
1178  * Determines, for each path in prefixes, whether the "prefix"
1179  * is an ancestor directory of path.  Returns the length of the longest
1180  * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1181  * is an ancestor.  (Note that this means 0 is returned if prefixes is
1182  * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1183  * are not considered to be their own ancestors.  path must be in a
1184  * canonical form: empty components, or "." or ".." components are not
1185  * allowed.
1186  */
1187 int longest_ancestor_length(const char *path, struct string_list *prefixes)
1188 {
1189         int i, max_len = -1;
1190
1191         if (!strcmp(path, "/"))
1192                 return -1;
1193
1194         for (i = 0; i < prefixes->nr; i++) {
1195                 const char *ceil = prefixes->items[i].string;
1196                 int len = strlen(ceil);
1197
1198                 if (len == 1 && ceil[0] == '/')
1199                         len = 0; /* root matches anything, with length 0 */
1200                 else if (!strncmp(path, ceil, len) && path[len] == '/')
1201                         ; /* match of length len */
1202                 else
1203                         continue; /* no match */
1204
1205                 if (len > max_len)
1206                         max_len = len;
1207         }
1208
1209         return max_len;
1210 }
1211
1212 /* strip arbitrary amount of directory separators at end of path */
1213 static inline int chomp_trailing_dir_sep(const char *path, int len)
1214 {
1215         while (len && is_dir_sep(path[len - 1]))
1216                 len--;
1217         return len;
1218 }
1219
1220 /*
1221  * If path ends with suffix (complete path components), returns the
1222  * part before suffix (sans trailing directory separators).
1223  * Otherwise returns NULL.
1224  */
1225 char *strip_path_suffix(const char *path, const char *suffix)
1226 {
1227         int path_len = strlen(path), suffix_len = strlen(suffix);
1228
1229         while (suffix_len) {
1230                 if (!path_len)
1231                         return NULL;
1232
1233                 if (is_dir_sep(path[path_len - 1])) {
1234                         if (!is_dir_sep(suffix[suffix_len - 1]))
1235                                 return NULL;
1236                         path_len = chomp_trailing_dir_sep(path, path_len);
1237                         suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
1238                 }
1239                 else if (path[--path_len] != suffix[--suffix_len])
1240                         return NULL;
1241         }
1242
1243         if (path_len && !is_dir_sep(path[path_len - 1]))
1244                 return NULL;
1245         return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
1246 }
1247
1248 int daemon_avoid_alias(const char *p)
1249 {
1250         int sl, ndot;
1251
1252         /*
1253          * This resurrects the belts and suspenders paranoia check by HPA
1254          * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
1255          * does not do getcwd() based path canonicalization.
1256          *
1257          * sl becomes true immediately after seeing '/' and continues to
1258          * be true as long as dots continue after that without intervening
1259          * non-dot character.
1260          */
1261         if (!p || (*p != '/' && *p != '~'))
1262                 return -1;
1263         sl = 1; ndot = 0;
1264         p++;
1265
1266         while (1) {
1267                 char ch = *p++;
1268                 if (sl) {
1269                         if (ch == '.')
1270                                 ndot++;
1271                         else if (ch == '/') {
1272                                 if (ndot < 3)
1273                                         /* reject //, /./ and /../ */
1274                                         return -1;
1275                                 ndot = 0;
1276                         }
1277                         else if (ch == 0) {
1278                                 if (0 < ndot && ndot < 3)
1279                                         /* reject /.$ and /..$ */
1280                                         return -1;
1281                                 return 0;
1282                         }
1283                         else
1284                                 sl = ndot = 0;
1285                 }
1286                 else if (ch == 0)
1287                         return 0;
1288                 else if (ch == '/') {
1289                         sl = 1;
1290                         ndot = 0;
1291                 }
1292         }
1293 }
1294
1295 static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
1296 {
1297         if (len < skip)
1298                 return 0;
1299         len -= skip;
1300         path += skip;
1301         while (len-- > 0) {
1302                 char c = *(path++);
1303                 if (c != ' ' && c != '.')
1304                         return 0;
1305         }
1306         return 1;
1307 }
1308
1309 int is_ntfs_dotgit(const char *name)
1310 {
1311         size_t len;
1312
1313         for (len = 0; ; len++)
1314                 if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
1315                         if (only_spaces_and_periods(name, len, 4) &&
1316                                         !strncasecmp(name, ".git", 4))
1317                                 return 1;
1318                         if (only_spaces_and_periods(name, len, 5) &&
1319                                         !strncasecmp(name, "git~1", 5))
1320                                 return 1;
1321                         if (name[len] != '\\')
1322                                 return 0;
1323                         name += len + 1;
1324                         len = -1;
1325                 }
1326 }
1327
1328 static int is_ntfs_dot_generic(const char *name,
1329                                const char *dotgit_name,
1330                                size_t len,
1331                                const char *dotgit_ntfs_shortname_prefix)
1332 {
1333         int saw_tilde;
1334         size_t i;
1335
1336         if ((name[0] == '.' && !strncasecmp(name + 1, dotgit_name, len))) {
1337                 i = len + 1;
1338 only_spaces_and_periods:
1339                 for (;;) {
1340                         char c = name[i++];
1341                         if (!c)
1342                                 return 1;
1343                         if (c != ' ' && c != '.')
1344                                 return 0;
1345                 }
1346         }
1347
1348         /*
1349          * Is it a regular NTFS short name, i.e. shortened to 6 characters,
1350          * followed by ~1, ... ~4?
1351          */
1352         if (!strncasecmp(name, dotgit_name, 6) && name[6] == '~' &&
1353             name[7] >= '1' && name[7] <= '4') {
1354                 i = 8;
1355                 goto only_spaces_and_periods;
1356         }
1357
1358         /*
1359          * Is it a fall-back NTFS short name (for details, see
1360          * https://en.wikipedia.org/wiki/8.3_filename?
1361          */
1362         for (i = 0, saw_tilde = 0; i < 8; i++)
1363                 if (name[i] == '\0')
1364                         return 0;
1365                 else if (saw_tilde) {
1366                         if (name[i] < '0' || name[i] > '9')
1367                                 return 0;
1368                 } else if (name[i] == '~') {
1369                         if (name[++i] < '1' || name[i] > '9')
1370                                 return 0;
1371                         saw_tilde = 1;
1372                 } else if (i >= 6)
1373                         return 0;
1374                 else if (name[i] & 0x80) {
1375                         /*
1376                          * We know our needles contain only ASCII, so we clamp
1377                          * here to make the results of tolower() sane.
1378                          */
1379                         return 0;
1380                 } else if (tolower(name[i]) != dotgit_ntfs_shortname_prefix[i])
1381                         return 0;
1382
1383         goto only_spaces_and_periods;
1384 }
1385
1386 /*
1387  * Inline helper to make sure compiler resolves strlen() on literals at
1388  * compile time.
1389  */
1390 static inline int is_ntfs_dot_str(const char *name, const char *dotgit_name,
1391                                   const char *dotgit_ntfs_shortname_prefix)
1392 {
1393         return is_ntfs_dot_generic(name, dotgit_name, strlen(dotgit_name),
1394                                    dotgit_ntfs_shortname_prefix);
1395 }
1396
1397 int is_ntfs_dotgitmodules(const char *name)
1398 {
1399         return is_ntfs_dot_str(name, "gitmodules", "gi7eba");
1400 }
1401
1402 int is_ntfs_dotgitignore(const char *name)
1403 {
1404         return is_ntfs_dot_str(name, "gitignore", "gi250a");
1405 }
1406
1407 int is_ntfs_dotgitattributes(const char *name)
1408 {
1409         return is_ntfs_dot_str(name, "gitattributes", "gi7d29");
1410 }
1411
1412 int looks_like_command_line_option(const char *str)
1413 {
1414         return str && str[0] == '-';
1415 }
1416
1417 char *xdg_config_home(const char *filename)
1418 {
1419         const char *home, *config_home;
1420
1421         assert(filename);
1422         config_home = getenv("XDG_CONFIG_HOME");
1423         if (config_home && *config_home)
1424                 return mkpathdup("%s/git/%s", config_home, filename);
1425
1426         home = getenv("HOME");
1427         if (home)
1428                 return mkpathdup("%s/.config/git/%s", home, filename);
1429         return NULL;
1430 }
1431
1432 char *xdg_cache_home(const char *filename)
1433 {
1434         const char *home, *cache_home;
1435
1436         assert(filename);
1437         cache_home = getenv("XDG_CACHE_HOME");
1438         if (cache_home && *cache_home)
1439                 return mkpathdup("%s/git/%s", cache_home, filename);
1440
1441         home = getenv("HOME");
1442         if (home)
1443                 return mkpathdup("%s/.cache/git/%s", home, filename);
1444         return NULL;
1445 }
1446
1447 REPO_GIT_PATH_FUNC(cherry_pick_head, "CHERRY_PICK_HEAD")
1448 REPO_GIT_PATH_FUNC(revert_head, "REVERT_HEAD")
1449 REPO_GIT_PATH_FUNC(squash_msg, "SQUASH_MSG")
1450 REPO_GIT_PATH_FUNC(merge_msg, "MERGE_MSG")
1451 REPO_GIT_PATH_FUNC(merge_rr, "MERGE_RR")
1452 REPO_GIT_PATH_FUNC(merge_mode, "MERGE_MODE")
1453 REPO_GIT_PATH_FUNC(merge_head, "MERGE_HEAD")
1454 REPO_GIT_PATH_FUNC(fetch_head, "FETCH_HEAD")
1455 REPO_GIT_PATH_FUNC(shallow, "shallow")