path.c

   1 /*
   2  * Utilities for paths and pathnames
   3  */
   4 #include "cache.h"
   5 #include "strbuf.h"
   6 #include "string-list.h"
   7 #include "dir.h"
   8
   9 static int get_st_mode_bits(const char *path, int *mode)
  10 {
  11         struct stat st;
  12         if (lstat(path, &st) < 0)
  13                 return -1;
  14         *mode = st.st_mode;
  15         return 0;
  16 }
  17
  18 static char bad_path[] = "/bad-path/";
  19
  20 static struct strbuf *get_pathname(void)
  21 {
  22         static struct strbuf pathname_array[4] = {
  23                 STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
  24         };
  25         static int index;
  26         struct strbuf *sb = &pathname_array[3 & ++index];
  27         strbuf_reset(sb);
  28         return sb;
  29 }
  30
  31 static char *cleanup_path(char *path)
  32 {
  33         /* Clean it up */
  34         if (!memcmp(path, "./", 2)) {
  35                 path += 2;
  36                 while (*path == '/')
  37                         path++;
  38         }
  39         return path;
  40 }
  41
  42 static void strbuf_cleanup_path(struct strbuf *sb)
  43 {
  44         char *path = cleanup_path(sb->buf);
  45         if (path > sb->buf)
  46                 strbuf_remove(sb, 0, path - sb->buf);
  47 }
  48
  49 char *mksnpath(char *buf, size_t n, const char *fmt, ...)
  50 {
  51         va_list args;
  52         unsigned len;
  53
  54         va_start(args, fmt);
  55         len = vsnprintf(buf, n, fmt, args);
  56         va_end(args);
  57         if (len >= n) {
  58                 strlcpy(buf, bad_path, n);
  59                 return buf;
  60         }
  61         return cleanup_path(buf);
  62 }
  63
  64 static int dir_prefix(const char *buf, const char *dir)
  65 {
  66         int len = strlen(dir);
  67         return !strncmp(buf, dir, len) &&
  68                 (is_dir_sep(buf[len]) || buf[len] == '\0');
  69 }
  70
  71 /* $buf =~ m|$dir/+$file| but without regex */
  72 static int is_dir_file(const char *buf, const char *dir, const char *file)
  73 {
  74         int len = strlen(dir);
  75         if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
  76                 return 0;
  77         while (is_dir_sep(buf[len]))
  78                 len++;
  79         return !strcmp(buf + len, file);
  80 }
  81
  82 static void replace_dir(struct strbuf *buf, int len, const char *newdir)
  83 {
  84         int newlen = strlen(newdir);
  85         int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
  86                 !is_dir_sep(newdir[newlen - 1]);
  87         if (need_sep)
  88                 len--;   /* keep one char, to be replaced with '/'  */
  89         strbuf_splice(buf, 0, len, newdir, newlen);
  90         if (need_sep)
  91                 buf->buf[newlen] = '/';
  92 }
  93
  94 struct common_dir {
  95         /* Not considered garbage for report_linked_checkout_garbage */
  96         unsigned ignore_garbage:1;
  97         unsigned is_dir:1;
  98         /* Not common even though its parent is */
  99         unsigned exclude:1;
 100         const char *dirname;
 101 };
 102
 103 static struct common_dir common_list[] = {
 104         { 0, 1, 0, "branches" },
 105         { 0, 1, 0, "hooks" },
 106         { 0, 1, 0, "info" },
 107         { 0, 0, 1, "info/sparse-checkout" },
 108         { 1, 1, 0, "logs" },
 109         { 1, 1, 1, "logs/HEAD" },
 110         { 0, 1, 1, "logs/refs/bisect" },
 111         { 0, 1, 0, "lost-found" },
 112         { 0, 1, 0, "objects" },
 113         { 0, 1, 0, "refs" },
 114         { 0, 1, 1, "refs/bisect" },
 115         { 0, 1, 0, "remotes" },
 116         { 0, 1, 0, "worktrees" },
 117         { 0, 1, 0, "rr-cache" },
 118         { 0, 1, 0, "svn" },
 119         { 0, 0, 0, "config" },
 120         { 1, 0, 0, "gc.pid" },
 121         { 0, 0, 0, "packed-refs" },
 122         { 0, 0, 0, "shallow" },
 123         { 0, 0, 0, NULL }
 124 };
 125
 126 /*
 127  * A compressed trie.  A trie node consists of zero or more characters that
 128  * are common to all elements with this prefix, optionally followed by some
 129  * children.  If value is not NULL, the trie node is a terminal node.
 130  *
 131  * For example, consider the following set of strings:
 132  * abc
 133  * def
 134  * definite
 135  * definition
 136  *
 137  * The trie would look look like:
 138  * root: len = 0, children a and d non-NULL, value = NULL.
 139  *    a: len = 2, contents = bc, value = (data for "abc")
 140  *    d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
 141  *       i: len = 3, contents = nit, children e and i non-NULL, value = NULL
 142  *           e: len = 0, children all NULL, value = (data for "definite")
 143  *           i: len = 2, contents = on, children all NULL,
 144  *              value = (data for "definition")
 145  */
 146 struct trie {
 147         struct trie *children[256];
 148         int len;
 149         char *contents;
 150         void *value;
 151 };
 152
 153 static struct trie *make_trie_node(const char *key, void *value)
 154 {
 155         struct trie *new_node = xcalloc(1, sizeof(*new_node));
 156         new_node->len = strlen(key);
 157         if (new_node->len) {
 158                 new_node->contents = xmalloc(new_node->len);
 159                 memcpy(new_node->contents, key, new_node->len);
 160         }
 161         new_node->value = value;
 162         return new_node;
 163 }
 164
 165 /*
 166  * Add a key/value pair to a trie.  The key is assumed to be \0-terminated.
 167  * If there was an existing value for this key, return it.
 168  */
 169 static void *add_to_trie(struct trie *root, const char *key, void *value)
 170 {
 171         struct trie *child;
 172         void *old;
 173         int i;
 174
 175         if (!*key) {
 176                 /* we have reached the end of the key */
 177                 old = root->value;
 178                 root->value = value;
 179                 return old;
 180         }
 181
 182         for (i = 0; i < root->len; i++) {
 183                 if (root->contents[i] == key[i])
 184                         continue;
 185
 186                 /*
 187                  * Split this node: child will contain this node's
 188                  * existing children.
 189                  */
 190                 child = malloc(sizeof(*child));
 191                 memcpy(child->children, root->children, sizeof(root->children));
 192
 193                 child->len = root->len - i - 1;
 194                 if (child->len) {
 195                         child->contents = xstrndup(root->contents + i + 1,
 196                                                    child->len);
 197                 }
 198                 child->value = root->value;
 199                 root->value = NULL;
 200                 root->len = i;
 201
 202                 memset(root->children, 0, sizeof(root->children));
 203                 root->children[(unsigned char)root->contents[i]] = child;
 204
 205                 /* This is the newly-added child. */
 206                 root->children[(unsigned char)key[i]] =
 207                         make_trie_node(key + i + 1, value);
 208                 return NULL;
 209         }
 210
 211         /* We have matched the entire compressed section */
 212         if (key[i]) {
 213                 child = root->children[(unsigned char)key[root->len]];
 214                 if (child) {
 215                         return add_to_trie(child, key + root->len + 1, value);
 216                 } else {
 217                         child = make_trie_node(key + root->len + 1, value);
 218                         root->children[(unsigned char)key[root->len]] = child;
 219                         return NULL;
 220                 }
 221         }
 222
 223         old = root->value;
 224         root->value = value;
 225         return old;
 226 }
 227
 228 typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
 229
 230 /*
 231  * Search a trie for some key.  Find the longest /-or-\0-terminated
 232  * prefix of the key for which the trie contains a value.  Call fn
 233  * with the unmatched portion of the key and the found value, and
 234  * return its return value.  If there is no such prefix, return -1.
 235  *
 236  * The key is partially normalized: consecutive slashes are skipped.
 237  *
 238  * For example, consider the trie containing only [refs,
 239  * refs/worktree] (both with values).
 240  *
 241  * | key             | unmatched  | val from node | return value |
 242  * |-----------------|------------|---------------|--------------|
 243  * | a               | not called | n/a           | -1           |
 244  * | refs            | \0         | refs          | as per fn    |
 245  * | refs/           | /          | refs          | as per fn    |
 246  * | refs/w          | /w         | refs          | as per fn    |
 247  * | refs/worktree   | \0         | refs/worktree | as per fn    |
 248  * | refs/worktree/  | /          | refs/worktree | as per fn    |
 249  * | refs/worktree/a | /a         | refs/worktree | as per fn    |
 250  * |-----------------|------------|---------------|--------------|
 251  *
 252  */
 253 static int trie_find(struct trie *root, const char *key, match_fn fn,
 254                      void *baton)
 255 {
 256         int i;
 257         int result;
 258         struct trie *child;
 259
 260         if (!*key) {
 261                 /* we have reached the end of the key */
 262                 if (root->value && !root->len)
 263                         return fn(key, root->value, baton);
 264                 else
 265                         return -1;
 266         }
 267
 268         for (i = 0; i < root->len; i++) {
 269                 /* Partial path normalization: skip consecutive slashes. */
 270                 if (key[i] == '/' && key[i+1] == '/') {
 271                         key++;
 272                         continue;
 273                 }
 274                 if (root->contents[i] != key[i])
 275                         return -1;
 276         }
 277
 278         /* Matched the entire compressed section */
 279         key += i;
 280         if (!*key)
 281                 /* End of key */
 282                 return fn(key, root->value, baton);
 283
 284         /* Partial path normalization: skip consecutive slashes */
 285         while (key[0] == '/' && key[1] == '/')
 286                 key++;
 287
 288         child = root->children[(unsigned char)*key];
 289         if (child)
 290                 result = trie_find(child, key + 1, fn, baton);
 291         else
 292                 result = -1;
 293
 294         if (result >= 0 || (*key != '/' && *key != 0))
 295                 return result;
 296         if (root->value)
 297                 return fn(key, root->value, baton);
 298         else
 299                 return -1;
 300 }
 301
 302 static struct trie common_trie;
 303 static int common_trie_done_setup;
 304
 305 static void init_common_trie(void)
 306 {
 307         struct common_dir *p;
 308
 309         if (common_trie_done_setup)
 310                 return;
 311
 312         for (p = common_list; p->dirname; p++)
 313                 add_to_trie(&common_trie, p->dirname, p);
 314
 315         common_trie_done_setup = 1;
 316 }
 317
 318 /*
 319  * Helper function for update_common_dir: returns 1 if the dir
 320  * prefix is common.
 321  */
 322 static int check_common(const char *unmatched, void *value, void *baton)
 323 {
 324         struct common_dir *dir = value;
 325
 326         if (!dir)
 327                 return 0;
 328
 329         if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
 330                 return !dir->exclude;
 331
 332         if (!dir->is_dir && unmatched[0] == 0)
 333                 return !dir->exclude;
 334
 335         return 0;
 336 }
 337
 338 static void update_common_dir(struct strbuf *buf, int git_dir_len,
 339                               const char *common_dir)
 340 {
 341         char *base = buf->buf + git_dir_len;
 342         init_common_trie();
 343         if (!common_dir)
 344                 common_dir = get_git_common_dir();
 345         if (trie_find(&common_trie, base, check_common, NULL) > 0)
 346                 replace_dir(buf, git_dir_len, common_dir);
 347 }
 348
 349 void report_linked_checkout_garbage(void)
 350 {
 351         struct strbuf sb = STRBUF_INIT;
 352         const struct common_dir *p;
 353         int len;
 354
 355         if (!git_common_dir_env)
 356                 return;
 357         strbuf_addf(&sb, "%s/", get_git_dir());
 358         len = sb.len;
 359         for (p = common_list; p->dirname; p++) {
 360                 const char *path = p->dirname;
 361                 if (p->ignore_garbage)
 362                         continue;
 363                 strbuf_setlen(&sb, len);
 364                 strbuf_addstr(&sb, path);
 365                 if (file_exists(sb.buf))
 366                         report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
 367         }
 368         strbuf_release(&sb);
 369 }
 370
 371 static void adjust_git_path(struct strbuf *buf, int git_dir_len)
 372 {
 373         const char *base = buf->buf + git_dir_len;
 374         if (git_graft_env && is_dir_file(base, "info", "grafts"))
 375                 strbuf_splice(buf, 0, buf->len,
 376                               get_graft_file(), strlen(get_graft_file()));
 377         else if (git_index_env && !strcmp(base, "index"))
 378                 strbuf_splice(buf, 0, buf->len,
 379                               get_index_file(), strlen(get_index_file()));
 380         else if (git_db_env && dir_prefix(base, "objects"))
 381                 replace_dir(buf, git_dir_len + 7, get_object_directory());
 382         else if (git_hooks_path && dir_prefix(base, "hooks"))
 383                 replace_dir(buf, git_dir_len + 5, git_hooks_path);
 384         else if (git_common_dir_env)
 385                 update_common_dir(buf, git_dir_len, NULL);
 386 }
 387
 388 static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
 389 {
 390         int gitdir_len;
 391         strbuf_addstr(buf, get_git_dir());
 392         if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 393                 strbuf_addch(buf, '/');
 394         gitdir_len = buf->len;
 395         strbuf_vaddf(buf, fmt, args);
 396         adjust_git_path(buf, gitdir_len);
 397         strbuf_cleanup_path(buf);
 398 }
 399
 400 char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
 401 {
 402         va_list args;
 403         strbuf_reset(buf);
 404         va_start(args, fmt);
 405         do_git_path(buf, fmt, args);
 406         va_end(args);
 407         return buf->buf;
 408 }
 409
 410 void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 411 {
 412         va_list args;
 413         va_start(args, fmt);
 414         do_git_path(sb, fmt, args);
 415         va_end(args);
 416 }
 417
 418 const char *git_path(const char *fmt, ...)
 419 {
 420         struct strbuf *pathname = get_pathname();
 421         va_list args;
 422         va_start(args, fmt);
 423         do_git_path(pathname, fmt, args);
 424         va_end(args);
 425         return pathname->buf;
 426 }
 427
 428 char *git_pathdup(const char *fmt, ...)
 429 {
 430         struct strbuf path = STRBUF_INIT;
 431         va_list args;
 432         va_start(args, fmt);
 433         do_git_path(&path, fmt, args);
 434         va_end(args);
 435         return strbuf_detach(&path, NULL);
 436 }
 437
 438 char *mkpathdup(const char *fmt, ...)
 439 {
 440         struct strbuf sb = STRBUF_INIT;
 441         va_list args;
 442         va_start(args, fmt);
 443         strbuf_vaddf(&sb, fmt, args);
 444         va_end(args);
 445         strbuf_cleanup_path(&sb);
 446         return strbuf_detach(&sb, NULL);
 447 }
 448
 449 const char *mkpath(const char *fmt, ...)
 450 {
 451         va_list args;
 452         struct strbuf *pathname = get_pathname();
 453         va_start(args, fmt);
 454         strbuf_vaddf(pathname, fmt, args);
 455         va_end(args);
 456         return cleanup_path(pathname->buf);
 457 }
 458
 459 static void do_submodule_path(struct strbuf *buf, const char *path,
 460                               const char *fmt, va_list args)
 461 {
 462         const char *git_dir;
 463         struct strbuf git_submodule_common_dir = STRBUF_INIT;
 464         struct strbuf git_submodule_dir = STRBUF_INIT;
 465
 466         strbuf_addstr(buf, path);
 467         strbuf_complete(buf, '/');
 468         strbuf_addstr(buf, ".git");
 469
 470         git_dir = read_gitfile(buf->buf);
 471         if (git_dir) {
 472                 strbuf_reset(buf);
 473                 strbuf_addstr(buf, git_dir);
 474         }
 475         strbuf_addch(buf, '/');
 476         strbuf_addstr(&git_submodule_dir, buf->buf);
 477
 478         strbuf_vaddf(buf, fmt, args);
 479
 480         if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
 481                 update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
 482
 483         strbuf_cleanup_path(buf);
 484
 485         strbuf_release(&git_submodule_dir);
 486         strbuf_release(&git_submodule_common_dir);
 487 }
 488
 489 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
 490 {
 491         va_list args;
 492         struct strbuf buf = STRBUF_INIT;
 493         va_start(args, fmt);
 494         do_submodule_path(&buf, path, fmt, args);
 495         va_end(args);
 496         return strbuf_detach(&buf, NULL);
 497 }
 498
 499 void strbuf_git_path_submodule(struct strbuf *buf, const char *path,
 500                                const char *fmt, ...)
 501 {
 502         va_list args;
 503         va_start(args, fmt);
 504         do_submodule_path(buf, path, fmt, args);
 505         va_end(args);
 506 }
 507
 508 int validate_headref(const char *path)
 509 {
 510         struct stat st;
 511         char *buf, buffer[256];
 512         unsigned char sha1[20];
 513         int fd;
 514         ssize_t len;
 515
 516         if (lstat(path, &st) < 0)
 517                 return -1;
 518
 519         /* Make sure it is a "refs/.." symlink */
 520         if (S_ISLNK(st.st_mode)) {
 521                 len = readlink(path, buffer, sizeof(buffer)-1);
 522                 if (len >= 5 && !memcmp("refs/", buffer, 5))
 523                         return 0;
 524                 return -1;
 525         }
 526
 527         /*
 528          * Anything else, just open it and try to see if it is a symbolic ref.
 529          */
 530         fd = open(path, O_RDONLY);
 531         if (fd < 0)
 532                 return -1;
 533         len = read_in_full(fd, buffer, sizeof(buffer)-1);
 534         close(fd);
 535
 536         /*
 537          * Is it a symbolic ref?
 538          */
 539         if (len < 4)
 540                 return -1;
 541         if (!memcmp("ref:", buffer, 4)) {
 542                 buf = buffer + 4;
 543                 len -= 4;
 544                 while (len && isspace(*buf))
 545                         buf++, len--;
 546                 if (len >= 5 && !memcmp("refs/", buf, 5))
 547                         return 0;
 548         }
 549
 550         /*
 551          * Is this a detached HEAD?
 552          */
 553         if (!get_sha1_hex(buffer, sha1))
 554                 return 0;
 555
 556         return -1;
 557 }
 558
 559 static struct passwd *getpw_str(const char *username, size_t len)
 560 {
 561         struct passwd *pw;
 562         char *username_z = xmemdupz(username, len);
 563         pw = getpwnam(username_z);
 564         free(username_z);
 565         return pw;
 566 }
 567
 568 /*
 569  * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
 570  * then it is a newly allocated string. Returns NULL on getpw failure or
 571  * if path is NULL.
 572  */
 573 char *expand_user_path(const char *path)
 574 {
 575         struct strbuf user_path = STRBUF_INIT;
 576         const char *to_copy = path;
 577
 578         if (path == NULL)
 579                 goto return_null;
 580         if (path[0] == '~') {
 581                 const char *first_slash = strchrnul(path, '/');
 582                 const char *username = path + 1;
 583                 size_t username_len = first_slash - username;
 584                 if (username_len == 0) {
 585                         const char *home = getenv("HOME");
 586                         if (!home)
 587                                 goto return_null;
 588                         strbuf_addstr(&user_path, home);
 589 #ifdef GIT_WINDOWS_NATIVE
 590                         convert_slashes(user_path.buf);
 591 #endif
 592                 } else {
 593                         struct passwd *pw = getpw_str(username, username_len);
 594                         if (!pw)
 595                                 goto return_null;
 596                         strbuf_addstr(&user_path, pw->pw_dir);
 597                 }
 598                 to_copy = first_slash;
 599         }
 600         strbuf_addstr(&user_path, to_copy);
 601         return strbuf_detach(&user_path, NULL);
 602 return_null:
 603         strbuf_release(&user_path);
 604         return NULL;
 605 }
 606
 607 /*
 608  * First, one directory to try is determined by the following algorithm.
 609  *
 610  * (0) If "strict" is given, the path is used as given and no DWIM is
 611  *     done. Otherwise:
 612  * (1) "~/path" to mean path under the running user's home directory;
 613  * (2) "~user/path" to mean path under named user's home directory;
 614  * (3) "relative/path" to mean cwd relative directory; or
 615  * (4) "/absolute/path" to mean absolute directory.
 616  *
 617  * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
 618  * in this order. We select the first one that is a valid git repository, and
 619  * chdir() to it. If none match, or we fail to chdir, we return NULL.
 620  *
 621  * If all goes well, we return the directory we used to chdir() (but
 622  * before ~user is expanded), avoiding getcwd() resolving symbolic
 623  * links.  User relative paths are also returned as they are given,
 624  * except DWIM suffixing.
 625  */
 626 const char *enter_repo(const char *path, int strict)
 627 {
 628         static struct strbuf validated_path = STRBUF_INIT;
 629         static struct strbuf used_path = STRBUF_INIT;
 630
 631         if (!path)
 632                 return NULL;
 633
 634         if (!strict) {
 635                 static const char *suffix[] = {
 636                         "/.git", "", ".git/.git", ".git", NULL,
 637                 };
 638                 const char *gitfile;
 639                 int len = strlen(path);
 640                 int i;
 641                 while ((1 < len) && (path[len-1] == '/'))
 642                         len--;
 643
 644                 /*
 645                  * We can handle arbitrary-sized buffers, but this remains as a
 646                  * sanity check on untrusted input.
 647                  */
 648                 if (PATH_MAX <= len)
 649                         return NULL;
 650
 651                 strbuf_reset(&used_path);
 652                 strbuf_reset(&validated_path);
 653                 strbuf_add(&used_path, path, len);
 654                 strbuf_add(&validated_path, path, len);
 655
 656                 if (used_path.buf[0] == '~') {
 657                         char *newpath = expand_user_path(used_path.buf);
 658                         if (!newpath)
 659                                 return NULL;
 660                         strbuf_attach(&used_path, newpath, strlen(newpath),
 661                                       strlen(newpath));
 662                 }
 663                 for (i = 0; suffix[i]; i++) {
 664                         struct stat st;
 665                         size_t baselen = used_path.len;
 666                         strbuf_addstr(&used_path, suffix[i]);
 667                         if (!stat(used_path.buf, &st) &&
 668                             (S_ISREG(st.st_mode) ||
 669                             (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
 670                                 strbuf_addstr(&validated_path, suffix[i]);
 671                                 break;
 672                         }
 673                         strbuf_setlen(&used_path, baselen);
 674                 }
 675                 if (!suffix[i])
 676                         return NULL;
 677                 gitfile = read_gitfile(used_path.buf);
 678                 if (gitfile) {
 679                         strbuf_reset(&used_path);
 680                         strbuf_addstr(&used_path, gitfile);
 681                 }
 682                 if (chdir(used_path.buf))
 683                         return NULL;
 684                 path = validated_path.buf;
 685         }
 686         else {
 687                 const char *gitfile = read_gitfile(path);
 688                 if (gitfile)
 689                         path = gitfile;
 690                 if (chdir(path))
 691                         return NULL;
 692         }
 693
 694         if (is_git_directory(".")) {
 695                 set_git_dir(".");
 696                 check_repository_format();
 697                 return path;
 698         }
 699
 700         return NULL;
 701 }
 702
 703 static int calc_shared_perm(int mode)
 704 {
 705         int tweak;
 706
 707         if (shared_repository < 0)
 708                 tweak = -shared_repository;
 709         else
 710                 tweak = shared_repository;
 711
 712         if (!(mode & S_IWUSR))
 713                 tweak &= ~0222;
 714         if (mode & S_IXUSR)
 715                 /* Copy read bits to execute bits */
 716                 tweak |= (tweak & 0444) >> 2;
 717         if (shared_repository < 0)
 718                 mode = (mode & ~0777) | tweak;
 719         else
 720                 mode |= tweak;
 721
 722         return mode;
 723 }
 724
 725
 726 int adjust_shared_perm(const char *path)
 727 {
 728         int old_mode, new_mode;
 729
 730         if (!shared_repository)
 731                 return 0;
 732         if (get_st_mode_bits(path, &old_mode) < 0)
 733                 return -1;
 734
 735         new_mode = calc_shared_perm(old_mode);
 736         if (S_ISDIR(old_mode)) {
 737                 /* Copy read bits to execute bits */
 738                 new_mode |= (new_mode & 0444) >> 2;
 739                 new_mode |= FORCE_DIR_SET_GID;
 740         }
 741
 742         if (((old_mode ^ new_mode) & ~S_IFMT) &&
 743                         chmod(path, (new_mode & ~S_IFMT)) < 0)
 744                 return -2;
 745         return 0;
 746 }
 747
 748 void safe_create_dir(const char *dir, int share)
 749 {
 750         if (mkdir(dir, 0777) < 0) {
 751                 if (errno != EEXIST) {
 752                         perror(dir);
 753                         exit(1);
 754                 }
 755         }
 756         else if (share && adjust_shared_perm(dir))
 757                 die(_("Could not make %s writable by group"), dir);
 758 }
 759
 760 static int have_same_root(const char *path1, const char *path2)
 761 {
 762         int is_abs1, is_abs2;
 763
 764         is_abs1 = is_absolute_path(path1);
 765         is_abs2 = is_absolute_path(path2);
 766         return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
 767                (!is_abs1 && !is_abs2);
 768 }
 769
 770 /*
 771  * Give path as relative to prefix.
 772  *
 773  * The strbuf may or may not be used, so do not assume it contains the
 774  * returned path.
 775  */
 776 const char *relative_path(const char *in, const char *prefix,
 777                           struct strbuf *sb)
 778 {
 779         int in_len = in ? strlen(in) : 0;
 780         int prefix_len = prefix ? strlen(prefix) : 0;
 781         int in_off = 0;
 782         int prefix_off = 0;
 783         int i = 0, j = 0;
 784
 785         if (!in_len)
 786                 return "./";
 787         else if (!prefix_len)
 788                 return in;
 789
 790         if (have_same_root(in, prefix))
 791                 /* bypass dos_drive, for "c:" is identical to "C:" */
 792                 i = j = has_dos_drive_prefix(in);
 793         else {
 794                 return in;
 795         }
 796
 797         while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
 798                 if (is_dir_sep(prefix[i])) {
 799                         while (is_dir_sep(prefix[i]))
 800                                 i++;
 801                         while (is_dir_sep(in[j]))
 802                                 j++;
 803                         prefix_off = i;
 804                         in_off = j;
 805                 } else {
 806                         i++;
 807                         j++;
 808                 }
 809         }
 810
 811         if (
 812             /* "prefix" seems like prefix of "in" */
 813             i >= prefix_len &&
 814             /*
 815              * but "/foo" is not a prefix of "/foobar"
 816              * (i.e. prefix not end with '/')
 817              */
 818             prefix_off < prefix_len) {
 819                 if (j >= in_len) {
 820                         /* in="/a/b", prefix="/a/b" */
 821                         in_off = in_len;
 822                 } else if (is_dir_sep(in[j])) {
 823                         /* in="/a/b/c", prefix="/a/b" */
 824                         while (is_dir_sep(in[j]))
 825                                 j++;
 826                         in_off = j;
 827                 } else {
 828                         /* in="/a/bbb/c", prefix="/a/b" */
 829                         i = prefix_off;
 830                 }
 831         } else if (
 832                    /* "in" is short than "prefix" */
 833                    j >= in_len &&
 834                    /* "in" not end with '/' */
 835                    in_off < in_len) {
 836                 if (is_dir_sep(prefix[i])) {
 837                         /* in="/a/b", prefix="/a/b/c/" */
 838                         while (is_dir_sep(prefix[i]))
 839                                 i++;
 840                         in_off = in_len;
 841                 }
 842         }
 843         in += in_off;
 844         in_len -= in_off;
 845
 846         if (i >= prefix_len) {
 847                 if (!in_len)
 848                         return "./";
 849                 else
 850                         return in;
 851         }
 852
 853         strbuf_reset(sb);
 854         strbuf_grow(sb, in_len);
 855
 856         while (i < prefix_len) {
 857                 if (is_dir_sep(prefix[i])) {
 858                         strbuf_addstr(sb, "../");
 859                         while (is_dir_sep(prefix[i]))
 860                                 i++;
 861                         continue;
 862                 }
 863                 i++;
 864         }
 865         if (!is_dir_sep(prefix[prefix_len - 1]))
 866                 strbuf_addstr(sb, "../");
 867
 868         strbuf_addstr(sb, in);
 869
 870         return sb->buf;
 871 }
 872
 873 /*
 874  * A simpler implementation of relative_path
 875  *
 876  * Get relative path by removing "prefix" from "in". This function
 877  * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
 878  * to increase performance when traversing the path to work_tree.
 879  */
 880 const char *remove_leading_path(const char *in, const char *prefix)
 881 {
 882         static struct strbuf buf = STRBUF_INIT;
 883         int i = 0, j = 0;
 884
 885         if (!prefix || !prefix[0])
 886                 return in;
 887         while (prefix[i]) {
 888                 if (is_dir_sep(prefix[i])) {
 889                         if (!is_dir_sep(in[j]))
 890                                 return in;
 891                         while (is_dir_sep(prefix[i]))
 892                                 i++;
 893                         while (is_dir_sep(in[j]))
 894                                 j++;
 895                         continue;
 896                 } else if (in[j] != prefix[i]) {
 897                         return in;
 898                 }
 899                 i++;
 900                 j++;
 901         }
 902         if (
 903             /* "/foo" is a prefix of "/foo" */
 904             in[j] &&
 905             /* "/foo" is not a prefix of "/foobar" */
 906             !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
 907            )
 908                 return in;
 909         while (is_dir_sep(in[j]))
 910                 j++;
 911
 912         strbuf_reset(&buf);
 913         if (!in[j])
 914                 strbuf_addstr(&buf, ".");
 915         else
 916                 strbuf_addstr(&buf, in + j);
 917         return buf.buf;
 918 }
 919
 920 /*
 921  * It is okay if dst == src, but they should not overlap otherwise.
 922  *
 923  * Performs the following normalizations on src, storing the result in dst:
 924  * - Ensures that components are separated by '/' (Windows only)
 925  * - Squashes sequences of '/'.
 926  * - Removes "." components.
 927  * - Removes ".." components, and the components the precede them.
 928  * Returns failure (non-zero) if a ".." component appears as first path
 929  * component anytime during the normalization. Otherwise, returns success (0).
 930  *
 931  * Note that this function is purely textual.  It does not follow symlinks,
 932  * verify the existence of the path, or make any system calls.
 933  *
 934  * prefix_len != NULL is for a specific case of prefix_pathspec():
 935  * assume that src == dst and src[0..prefix_len-1] is already
 936  * normalized, any time "../" eats up to the prefix_len part,
 937  * prefix_len is reduced. In the end prefix_len is the remaining
 938  * prefix that has not been overridden by user pathspec.
 939  *
 940  * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
 941  * For everything but the root folder itself, the normalized path should not
 942  * end with a '/', then the callers need to be fixed up accordingly.
 943  *
 944  */
 945 int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
 946 {
 947         char *dst0;
 948         int i;
 949
 950         for (i = has_dos_drive_prefix(src); i > 0; i--)
 951                 *dst++ = *src++;
 952         dst0 = dst;
 953
 954         if (is_dir_sep(*src)) {
 955                 *dst++ = '/';
 956                 while (is_dir_sep(*src))
 957                         src++;
 958         }
 959
 960         for (;;) {
 961                 char c = *src;
 962
 963                 /*
 964                  * A path component that begins with . could be
 965                  * special:
 966                  * (1) "." and ends   -- ignore and terminate.
 967                  * (2) "./"           -- ignore them, eat slash and continue.
 968                  * (3) ".." and ends  -- strip one and terminate.
 969                  * (4) "../"          -- strip one, eat slash and continue.
 970                  */
 971                 if (c == '.') {
 972                         if (!src[1]) {
 973                                 /* (1) */
 974                                 src++;
 975                         } else if (is_dir_sep(src[1])) {
 976                                 /* (2) */
 977                                 src += 2;
 978                                 while (is_dir_sep(*src))
 979                                         src++;
 980                                 continue;
 981                         } else if (src[1] == '.') {
 982                                 if (!src[2]) {
 983                                         /* (3) */
 984                                         src += 2;
 985                                         goto up_one;
 986                                 } else if (is_dir_sep(src[2])) {
 987                                         /* (4) */
 988                                         src += 3;
 989                                         while (is_dir_sep(*src))
 990                                                 src++;
 991                                         goto up_one;
 992                                 }
 993                         }
 994                 }
 995
 996                 /* copy up to the next '/', and eat all '/' */
 997                 while ((c = *src++) != '\0' && !is_dir_sep(c))
 998                         *dst++ = c;
 999                 if (is_dir_sep(c)) {
1000                         *dst++ = '/';
1001                         while (is_dir_sep(c))
1002                                 c = *src++;
1003                         src--;
1004                 } else if (!c)
1005                         break;
1006                 continue;
1007
1008         up_one:
1009                 /*
1010                  * dst0..dst is prefix portion, and dst[-1] is '/';
1011                  * go up one level.
1012                  */
1013                 dst--;  /* go to trailing '/' */
1014                 if (dst <= dst0)
1015                         return -1;
1016                 /* Windows: dst[-1] cannot be backslash anymore */
1017                 while (dst0 < dst && dst[-1] != '/')
1018                         dst--;
1019                 if (prefix_len && *prefix_len > dst - dst0)
1020                         *prefix_len = dst - dst0;
1021         }
1022         *dst = '\0';
1023         return 0;
1024 }
1025
1026 int normalize_path_copy(char *dst, const char *src)
1027 {
1028         return normalize_path_copy_len(dst, src, NULL);
1029 }
1030
1031 /*
1032  * path = Canonical absolute path
1033  * prefixes = string_list containing normalized, absolute paths without
1034  * trailing slashes (except for the root directory, which is denoted by "/").
1035  *
1036  * Determines, for each path in prefixes, whether the "prefix"
1037  * is an ancestor directory of path.  Returns the length of the longest
1038  * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1039  * is an ancestor.  (Note that this means 0 is returned if prefixes is
1040  * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1041  * are not considered to be their own ancestors.  path must be in a
1042  * canonical form: empty components, or "." or ".." components are not
1043  * allowed.
1044  */
1045 int longest_ancestor_length(const char *path, struct string_list *prefixes)
1046 {
1047         int i, max_len = -1;
1048
1049         if (!strcmp(path, "/"))
1050                 return -1;
1051
1052         for (i = 0; i < prefixes->nr; i++) {
1053                 const char *ceil = prefixes->items[i].string;
1054                 int len = strlen(ceil);
1055
1056                 if (len == 1 && ceil[0] == '/')
1057                         len = 0; /* root matches anything, with length 0 */
1058                 else if (!strncmp(path, ceil, len) && path[len] == '/')
1059                         ; /* match of length len */
1060                 else
1061                         continue; /* no match */
1062
1063                 if (len > max_len)
1064                         max_len = len;
1065         }
1066
1067         return max_len;
1068 }
1069
1070 /* strip arbitrary amount of directory separators at end of path */
1071 static inline int chomp_trailing_dir_sep(const char *path, int len)
1072 {
1073         while (len && is_dir_sep(path[len - 1]))
1074                 len--;
1075         return len;
1076 }
1077
1078 /*
1079  * If path ends with suffix (complete path components), returns the
1080  * part before suffix (sans trailing directory separators).
1081  * Otherwise returns NULL.
1082  */
1083 char *strip_path_suffix(const char *path, const char *suffix)
1084 {
1085         int path_len = strlen(path), suffix_len = strlen(suffix);
1086
1087         while (suffix_len) {
1088                 if (!path_len)
1089                         return NULL;
1090
1091                 if (is_dir_sep(path[path_len - 1])) {
1092                         if (!is_dir_sep(suffix[suffix_len - 1]))
1093                                 return NULL;
1094                         path_len = chomp_trailing_dir_sep(path, path_len);
1095                         suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
1096                 }
1097                 else if (path[--path_len] != suffix[--suffix_len])
1098                         return NULL;
1099         }
1100
1101         if (path_len && !is_dir_sep(path[path_len - 1]))
1102                 return NULL;
1103         return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
1104 }
1105
1106 int daemon_avoid_alias(const char *p)
1107 {
1108         int sl, ndot;
1109
1110         /*
1111          * This resurrects the belts and suspenders paranoia check by HPA
1112          * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
1113          * does not do getcwd() based path canonicalization.
1114          *
1115          * sl becomes true immediately after seeing '/' and continues to
1116          * be true as long as dots continue after that without intervening
1117          * non-dot character.
1118          */
1119         if (!p || (*p != '/' && *p != '~'))
1120                 return -1;
1121         sl = 1; ndot = 0;
1122         p++;
1123
1124         while (1) {
1125                 char ch = *p++;
1126                 if (sl) {
1127                         if (ch == '.')
1128                                 ndot++;
1129                         else if (ch == '/') {
1130                                 if (ndot < 3)
1131                                         /* reject //, /./ and /../ */
1132                                         return -1;
1133                                 ndot = 0;
1134                         }
1135                         else if (ch == 0) {
1136                                 if (0 < ndot && ndot < 3)
1137                                         /* reject /.$ and /..$ */
1138                                         return -1;
1139                                 return 0;
1140                         }
1141                         else
1142                                 sl = ndot = 0;
1143                 }
1144                 else if (ch == 0)
1145                         return 0;
1146                 else if (ch == '/') {
1147                         sl = 1;
1148                         ndot = 0;
1149                 }
1150         }
1151 }
1152
1153 static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
1154 {
1155         if (len < skip)
1156                 return 0;
1157         len -= skip;
1158         path += skip;
1159         while (len-- > 0) {
1160                 char c = *(path++);
1161                 if (c != ' ' && c != '.')
1162                         return 0;
1163         }
1164         return 1;
1165 }
1166
1167 int is_ntfs_dotgit(const char *name)
1168 {
1169         int len;
1170
1171         for (len = 0; ; len++)
1172                 if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
1173                         if (only_spaces_and_periods(name, len, 4) &&
1174                                         !strncasecmp(name, ".git", 4))
1175                                 return 1;
1176                         if (only_spaces_and_periods(name, len, 5) &&
1177                                         !strncasecmp(name, "git~1", 5))
1178                                 return 1;
1179                         if (name[len] != '\\')
1180                                 return 0;
1181                         name += len + 1;
1182                         len = -1;
1183                 }
1184 }
1185
1186 char *xdg_config_home(const char *filename)
1187 {
1188         const char *home, *config_home;
1189
1190         assert(filename);
1191         config_home = getenv("XDG_CONFIG_HOME");
1192         if (config_home && *config_home)
1193                 return mkpathdup("%s/git/%s", config_home, filename);
1194
1195         home = getenv("HOME");
1196         if (home)
1197                 return mkpathdup("%s/.config/git/%s", home, filename);
1198         return NULL;
1199 }
1200
1201 GIT_PATH_FUNC(git_path_cherry_pick_head, "CHERRY_PICK_HEAD")
1202 GIT_PATH_FUNC(git_path_revert_head, "REVERT_HEAD")
1203 GIT_PATH_FUNC(git_path_squash_msg, "SQUASH_MSG")
1204 GIT_PATH_FUNC(git_path_merge_msg, "MERGE_MSG")
1205 GIT_PATH_FUNC(git_path_merge_rr, "MERGE_RR")
1206 GIT_PATH_FUNC(git_path_merge_mode, "MERGE_MODE")
1207 GIT_PATH_FUNC(git_path_merge_head, "MERGE_HEAD")
1208 GIT_PATH_FUNC(git_path_fetch_head, "FETCH_HEAD")
1209 GIT_PATH_FUNC(git_path_shallow, "shallow")