76a872297e507f7580c0c24a8b307f4d8188e21e
   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
  13static int get_st_mode_bits(const char *path, int *mode)
  14{
  15        struct stat st;
  16        if (lstat(path, &st) < 0)
  17                return -1;
  18        *mode = st.st_mode;
  19        return 0;
  20}
  21
  22static char bad_path[] = "/bad-path/";
  23
  24static struct strbuf *get_pathname(void)
  25{
  26        static struct strbuf pathname_array[4] = {
  27                STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
  28        };
  29        static int index;
  30        struct strbuf *sb = &pathname_array[index];
  31        index = (index + 1) % ARRAY_SIZE(pathname_array);
  32        strbuf_reset(sb);
  33        return sb;
  34}
  35
  36static char *cleanup_path(char *path)
  37{
  38        /* Clean it up */
  39        if (!memcmp(path, "./", 2)) {
  40                path += 2;
  41                while (*path == '/')
  42                        path++;
  43        }
  44        return path;
  45}
  46
  47static void strbuf_cleanup_path(struct strbuf *sb)
  48{
  49        char *path = cleanup_path(sb->buf);
  50        if (path > sb->buf)
  51                strbuf_remove(sb, 0, path - sb->buf);
  52}
  53
  54char *mksnpath(char *buf, size_t n, const char *fmt, ...)
  55{
  56        va_list args;
  57        unsigned len;
  58
  59        va_start(args, fmt);
  60        len = vsnprintf(buf, n, fmt, args);
  61        va_end(args);
  62        if (len >= n) {
  63                strlcpy(buf, bad_path, n);
  64                return buf;
  65        }
  66        return cleanup_path(buf);
  67}
  68
  69static int dir_prefix(const char *buf, const char *dir)
  70{
  71        int len = strlen(dir);
  72        return !strncmp(buf, dir, len) &&
  73                (is_dir_sep(buf[len]) || buf[len] == '\0');
  74}
  75
  76/* $buf =~ m|$dir/+$file| but without regex */
  77static int is_dir_file(const char *buf, const char *dir, const char *file)
  78{
  79        int len = strlen(dir);
  80        if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
  81                return 0;
  82        while (is_dir_sep(buf[len]))
  83                len++;
  84        return !strcmp(buf + len, file);
  85}
  86
  87static void replace_dir(struct strbuf *buf, int len, const char *newdir)
  88{
  89        int newlen = strlen(newdir);
  90        int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
  91                !is_dir_sep(newdir[newlen - 1]);
  92        if (need_sep)
  93                len--;   /* keep one char, to be replaced with '/'  */
  94        strbuf_splice(buf, 0, len, newdir, newlen);
  95        if (need_sep)
  96                buf->buf[newlen] = '/';
  97}
  98
  99struct common_dir {
 100        /* Not considered garbage for report_linked_checkout_garbage */
 101        unsigned ignore_garbage:1;
 102        unsigned is_dir:1;
 103        /* Not common even though its parent is */
 104        unsigned exclude:1;
 105        const char *dirname;
 106};
 107
 108static struct common_dir common_list[] = {
 109        { 0, 1, 0, "branches" },
 110        { 0, 1, 0, "hooks" },
 111        { 0, 1, 0, "info" },
 112        { 0, 0, 1, "info/sparse-checkout" },
 113        { 1, 1, 0, "logs" },
 114        { 1, 1, 1, "logs/HEAD" },
 115        { 0, 1, 1, "logs/refs/bisect" },
 116        { 0, 1, 0, "lost-found" },
 117        { 0, 1, 0, "objects" },
 118        { 0, 1, 0, "refs" },
 119        { 0, 1, 1, "refs/bisect" },
 120        { 0, 1, 0, "remotes" },
 121        { 0, 1, 0, "worktrees" },
 122        { 0, 1, 0, "rr-cache" },
 123        { 0, 1, 0, "svn" },
 124        { 0, 0, 0, "config" },
 125        { 1, 0, 0, "gc.pid" },
 126        { 0, 0, 0, "packed-refs" },
 127        { 0, 0, 0, "shallow" },
 128        { 0, 0, 0, NULL }
 129};
 130
 131/*
 132 * A compressed trie.  A trie node consists of zero or more characters that
 133 * are common to all elements with this prefix, optionally followed by some
 134 * children.  If value is not NULL, the trie node is a terminal node.
 135 *
 136 * For example, consider the following set of strings:
 137 * abc
 138 * def
 139 * definite
 140 * definition
 141 *
 142 * The trie would look like:
 143 * root: len = 0, children a and d non-NULL, value = NULL.
 144 *    a: len = 2, contents = bc, value = (data for "abc")
 145 *    d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
 146 *       i: len = 3, contents = nit, children e and i non-NULL, value = NULL
 147 *           e: len = 0, children all NULL, value = (data for "definite")
 148 *           i: len = 2, contents = on, children all NULL,
 149 *              value = (data for "definition")
 150 */
 151struct trie {
 152        struct trie *children[256];
 153        int len;
 154        char *contents;
 155        void *value;
 156};
 157
 158static struct trie *make_trie_node(const char *key, void *value)
 159{
 160        struct trie *new_node = xcalloc(1, sizeof(*new_node));
 161        new_node->len = strlen(key);
 162        if (new_node->len) {
 163                new_node->contents = xmalloc(new_node->len);
 164                memcpy(new_node->contents, key, new_node->len);
 165        }
 166        new_node->value = value;
 167        return new_node;
 168}
 169
 170/*
 171 * Add a key/value pair to a trie.  The key is assumed to be \0-terminated.
 172 * If there was an existing value for this key, return it.
 173 */
 174static void *add_to_trie(struct trie *root, const char *key, void *value)
 175{
 176        struct trie *child;
 177        void *old;
 178        int i;
 179
 180        if (!*key) {
 181                /* we have reached the end of the key */
 182                old = root->value;
 183                root->value = value;
 184                return old;
 185        }
 186
 187        for (i = 0; i < root->len; i++) {
 188                if (root->contents[i] == key[i])
 189                        continue;
 190
 191                /*
 192                 * Split this node: child will contain this node's
 193                 * existing children.
 194                 */
 195                child = malloc(sizeof(*child));
 196                memcpy(child->children, root->children, sizeof(root->children));
 197
 198                child->len = root->len - i - 1;
 199                if (child->len) {
 200                        child->contents = xstrndup(root->contents + i + 1,
 201                                                   child->len);
 202                }
 203                child->value = root->value;
 204                root->value = NULL;
 205                root->len = i;
 206
 207                memset(root->children, 0, sizeof(root->children));
 208                root->children[(unsigned char)root->contents[i]] = child;
 209
 210                /* This is the newly-added child. */
 211                root->children[(unsigned char)key[i]] =
 212                        make_trie_node(key + i + 1, value);
 213                return NULL;
 214        }
 215
 216        /* We have matched the entire compressed section */
 217        if (key[i]) {
 218                child = root->children[(unsigned char)key[root->len]];
 219                if (child) {
 220                        return add_to_trie(child, key + root->len + 1, value);
 221                } else {
 222                        child = make_trie_node(key + root->len + 1, value);
 223                        root->children[(unsigned char)key[root->len]] = child;
 224                        return NULL;
 225                }
 226        }
 227
 228        old = root->value;
 229        root->value = value;
 230        return old;
 231}
 232
 233typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
 234
 235/*
 236 * Search a trie for some key.  Find the longest /-or-\0-terminated
 237 * prefix of the key for which the trie contains a value.  Call fn
 238 * with the unmatched portion of the key and the found value, and
 239 * return its return value.  If there is no such prefix, return -1.
 240 *
 241 * The key is partially normalized: consecutive slashes are skipped.
 242 *
 243 * For example, consider the trie containing only [refs,
 244 * refs/worktree] (both with values).
 245 *
 246 * | key             | unmatched  | val from node | return value |
 247 * |-----------------|------------|---------------|--------------|
 248 * | a               | not called | n/a           | -1           |
 249 * | refs            | \0         | refs          | as per fn    |
 250 * | refs/           | /          | refs          | as per fn    |
 251 * | refs/w          | /w         | refs          | as per fn    |
 252 * | refs/worktree   | \0         | refs/worktree | as per fn    |
 253 * | refs/worktree/  | /          | refs/worktree | as per fn    |
 254 * | refs/worktree/a | /a         | refs/worktree | as per fn    |
 255 * |-----------------|------------|---------------|--------------|
 256 *
 257 */
 258static int trie_find(struct trie *root, const char *key, match_fn fn,
 259                     void *baton)
 260{
 261        int i;
 262        int result;
 263        struct trie *child;
 264
 265        if (!*key) {
 266                /* we have reached the end of the key */
 267                if (root->value && !root->len)
 268                        return fn(key, root->value, baton);
 269                else
 270                        return -1;
 271        }
 272
 273        for (i = 0; i < root->len; i++) {
 274                /* Partial path normalization: skip consecutive slashes. */
 275                if (key[i] == '/' && key[i+1] == '/') {
 276                        key++;
 277                        continue;
 278                }
 279                if (root->contents[i] != key[i])
 280                        return -1;
 281        }
 282
 283        /* Matched the entire compressed section */
 284        key += i;
 285        if (!*key)
 286                /* End of key */
 287                return fn(key, root->value, baton);
 288
 289        /* Partial path normalization: skip consecutive slashes */
 290        while (key[0] == '/' && key[1] == '/')
 291                key++;
 292
 293        child = root->children[(unsigned char)*key];
 294        if (child)
 295                result = trie_find(child, key + 1, fn, baton);
 296        else
 297                result = -1;
 298
 299        if (result >= 0 || (*key != '/' && *key != 0))
 300                return result;
 301        if (root->value)
 302                return fn(key, root->value, baton);
 303        else
 304                return -1;
 305}
 306
 307static struct trie common_trie;
 308static int common_trie_done_setup;
 309
 310static void init_common_trie(void)
 311{
 312        struct common_dir *p;
 313
 314        if (common_trie_done_setup)
 315                return;
 316
 317        for (p = common_list; p->dirname; p++)
 318                add_to_trie(&common_trie, p->dirname, p);
 319
 320        common_trie_done_setup = 1;
 321}
 322
 323/*
 324 * Helper function for update_common_dir: returns 1 if the dir
 325 * prefix is common.
 326 */
 327static int check_common(const char *unmatched, void *value, void *baton)
 328{
 329        struct common_dir *dir = value;
 330
 331        if (!dir)
 332                return 0;
 333
 334        if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
 335                return !dir->exclude;
 336
 337        if (!dir->is_dir && unmatched[0] == 0)
 338                return !dir->exclude;
 339
 340        return 0;
 341}
 342
 343static void update_common_dir(struct strbuf *buf, int git_dir_len,
 344                              const char *common_dir)
 345{
 346        char *base = buf->buf + git_dir_len;
 347        init_common_trie();
 348        if (trie_find(&common_trie, base, check_common, NULL) > 0)
 349                replace_dir(buf, git_dir_len, common_dir);
 350}
 351
 352void report_linked_checkout_garbage(void)
 353{
 354        struct strbuf sb = STRBUF_INIT;
 355        const struct common_dir *p;
 356        int len;
 357
 358        if (!the_repository->different_commondir)
 359                return;
 360        strbuf_addf(&sb, "%s/", get_git_dir());
 361        len = sb.len;
 362        for (p = common_list; p->dirname; p++) {
 363                const char *path = p->dirname;
 364                if (p->ignore_garbage)
 365                        continue;
 366                strbuf_setlen(&sb, len);
 367                strbuf_addstr(&sb, path);
 368                if (file_exists(sb.buf))
 369                        report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
 370        }
 371        strbuf_release(&sb);
 372}
 373
 374static void adjust_git_path(const struct repository *repo,
 375                            struct strbuf *buf, int git_dir_len)
 376{
 377        const char *base = buf->buf + git_dir_len;
 378        if (is_dir_file(base, "info", "grafts"))
 379                strbuf_splice(buf, 0, buf->len,
 380                              repo->graft_file, strlen(repo->graft_file));
 381        else if (!strcmp(base, "index"))
 382                strbuf_splice(buf, 0, buf->len,
 383                              repo->index_file, strlen(repo->index_file));
 384        else if (dir_prefix(base, "objects"))
 385                replace_dir(buf, git_dir_len + 7, repo->objectdir);
 386        else if (git_hooks_path && dir_prefix(base, "hooks"))
 387                replace_dir(buf, git_dir_len + 5, git_hooks_path);
 388        else if (repo->different_commondir)
 389                update_common_dir(buf, git_dir_len, repo->commondir);
 390}
 391
 392static void strbuf_worktree_gitdir(struct strbuf *buf,
 393                                   const struct repository *repo,
 394                                   const struct worktree *wt)
 395{
 396        if (!wt)
 397                strbuf_addstr(buf, repo->gitdir);
 398        else if (!wt->id)
 399                strbuf_addstr(buf, repo->commondir);
 400        else
 401                strbuf_git_common_path(buf, repo, "worktrees/%s", wt->id);
 402}
 403
 404static void do_git_path(const struct repository *repo,
 405                        const struct worktree *wt, struct strbuf *buf,
 406                        const char *fmt, va_list args)
 407{
 408        int gitdir_len;
 409        strbuf_worktree_gitdir(buf, repo, wt);
 410        if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 411                strbuf_addch(buf, '/');
 412        gitdir_len = buf->len;
 413        strbuf_vaddf(buf, fmt, args);
 414        adjust_git_path(repo, buf, gitdir_len);
 415        strbuf_cleanup_path(buf);
 416}
 417
 418char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
 419{
 420        va_list args;
 421        strbuf_reset(buf);
 422        va_start(args, fmt);
 423        do_git_path(the_repository, NULL, buf, fmt, args);
 424        va_end(args);
 425        return buf->buf;
 426}
 427
 428void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 429{
 430        va_list args;
 431        va_start(args, fmt);
 432        do_git_path(the_repository, NULL, sb, fmt, args);
 433        va_end(args);
 434}
 435
 436const char *git_path(const char *fmt, ...)
 437{
 438        struct strbuf *pathname = get_pathname();
 439        va_list args;
 440        va_start(args, fmt);
 441        do_git_path(the_repository, NULL, pathname, fmt, args);
 442        va_end(args);
 443        return pathname->buf;
 444}
 445
 446char *git_pathdup(const char *fmt, ...)
 447{
 448        struct strbuf path = STRBUF_INIT;
 449        va_list args;
 450        va_start(args, fmt);
 451        do_git_path(the_repository, NULL, &path, fmt, args);
 452        va_end(args);
 453        return strbuf_detach(&path, NULL);
 454}
 455
 456char *mkpathdup(const char *fmt, ...)
 457{
 458        struct strbuf sb = STRBUF_INIT;
 459        va_list args;
 460        va_start(args, fmt);
 461        strbuf_vaddf(&sb, fmt, args);
 462        va_end(args);
 463        strbuf_cleanup_path(&sb);
 464        return strbuf_detach(&sb, NULL);
 465}
 466
 467const char *mkpath(const char *fmt, ...)
 468{
 469        va_list args;
 470        struct strbuf *pathname = get_pathname();
 471        va_start(args, fmt);
 472        strbuf_vaddf(pathname, fmt, args);
 473        va_end(args);
 474        return cleanup_path(pathname->buf);
 475}
 476
 477const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 478{
 479        struct strbuf *pathname = get_pathname();
 480        va_list args;
 481        va_start(args, fmt);
 482        do_git_path(the_repository, wt, pathname, fmt, args);
 483        va_end(args);
 484        return pathname->buf;
 485}
 486
 487/* Returns 0 on success, negative on failure. */
 488static int do_submodule_path(struct strbuf *buf, const char *path,
 489                             const char *fmt, va_list args)
 490{
 491        struct strbuf git_submodule_common_dir = STRBUF_INIT;
 492        struct strbuf git_submodule_dir = STRBUF_INIT;
 493        int ret;
 494
 495        ret = submodule_to_gitdir(&git_submodule_dir, path);
 496        if (ret)
 497                goto cleanup;
 498
 499        strbuf_complete(&git_submodule_dir, '/');
 500        strbuf_addbuf(buf, &git_submodule_dir);
 501        strbuf_vaddf(buf, fmt, args);
 502
 503        if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
 504                update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
 505
 506        strbuf_cleanup_path(buf);
 507
 508cleanup:
 509        strbuf_release(&git_submodule_dir);
 510        strbuf_release(&git_submodule_common_dir);
 511        return ret;
 512}
 513
 514char *git_pathdup_submodule(const char *path, const char *fmt, ...)
 515{
 516        int err;
 517        va_list args;
 518        struct strbuf buf = STRBUF_INIT;
 519        va_start(args, fmt);
 520        err = do_submodule_path(&buf, path, fmt, args);
 521        va_end(args);
 522        if (err) {
 523                strbuf_release(&buf);
 524                return NULL;
 525        }
 526        return strbuf_detach(&buf, NULL);
 527}
 528
 529int strbuf_git_path_submodule(struct strbuf *buf, const char *path,
 530                              const char *fmt, ...)
 531{
 532        int err;
 533        va_list args;
 534        va_start(args, fmt);
 535        err = do_submodule_path(buf, path, fmt, args);
 536        va_end(args);
 537
 538        return err;
 539}
 540
 541static void do_git_common_path(const struct repository *repo,
 542                               struct strbuf *buf,
 543                               const char *fmt,
 544                               va_list args)
 545{
 546        strbuf_addstr(buf, repo->commondir);
 547        if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 548                strbuf_addch(buf, '/');
 549        strbuf_vaddf(buf, fmt, args);
 550        strbuf_cleanup_path(buf);
 551}
 552
 553const char *git_common_path(const char *fmt, ...)
 554{
 555        struct strbuf *pathname = get_pathname();
 556        va_list args;
 557        va_start(args, fmt);
 558        do_git_common_path(the_repository, pathname, fmt, args);
 559        va_end(args);
 560        return pathname->buf;
 561}
 562
 563void strbuf_git_common_path(struct strbuf *sb,
 564                            const struct repository *repo,
 565                            const char *fmt, ...)
 566{
 567        va_list args;
 568        va_start(args, fmt);
 569        do_git_common_path(repo, sb, fmt, args);
 570        va_end(args);
 571}
 572
 573int validate_headref(const char *path)
 574{
 575        struct stat st;
 576        char *buf, buffer[256];
 577        unsigned char sha1[20];
 578        int fd;
 579        ssize_t len;
 580
 581        if (lstat(path, &st) < 0)
 582                return -1;
 583
 584        /* Make sure it is a "refs/.." symlink */
 585        if (S_ISLNK(st.st_mode)) {
 586                len = readlink(path, buffer, sizeof(buffer)-1);
 587                if (len >= 5 && !memcmp("refs/", buffer, 5))
 588                        return 0;
 589                return -1;
 590        }
 591
 592        /*
 593         * Anything else, just open it and try to see if it is a symbolic ref.
 594         */
 595        fd = open(path, O_RDONLY);
 596        if (fd < 0)
 597                return -1;
 598        len = read_in_full(fd, buffer, sizeof(buffer)-1);
 599        close(fd);
 600
 601        /*
 602         * Is it a symbolic ref?
 603         */
 604        if (len < 4)
 605                return -1;
 606        if (!memcmp("ref:", buffer, 4)) {
 607                buf = buffer + 4;
 608                len -= 4;
 609                while (len && isspace(*buf))
 610                        buf++, len--;
 611                if (len >= 5 && !memcmp("refs/", buf, 5))
 612                        return 0;
 613        }
 614
 615        /*
 616         * Is this a detached HEAD?
 617         */
 618        if (!get_sha1_hex(buffer, sha1))
 619                return 0;
 620
 621        return -1;
 622}
 623
 624static struct passwd *getpw_str(const char *username, size_t len)
 625{
 626        struct passwd *pw;
 627        char *username_z = xmemdupz(username, len);
 628        pw = getpwnam(username_z);
 629        free(username_z);
 630        return pw;
 631}
 632
 633/*
 634 * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
 635 * then it is a newly allocated string. Returns NULL on getpw failure or
 636 * if path is NULL.
 637 *
 638 * If real_home is true, real_path($HOME) is used in the expansion.
 639 */
 640char *expand_user_path(const char *path, int real_home)
 641{
 642        struct strbuf user_path = STRBUF_INIT;
 643        const char *to_copy = path;
 644
 645        if (path == NULL)
 646                goto return_null;
 647        if (path[0] == '~') {
 648                const char *first_slash = strchrnul(path, '/');
 649                const char *username = path + 1;
 650                size_t username_len = first_slash - username;
 651                if (username_len == 0) {
 652                        const char *home = getenv("HOME");
 653                        if (!home)
 654                                goto return_null;
 655                        if (real_home)
 656                                strbuf_addstr(&user_path, real_path(home));
 657                        else
 658                                strbuf_addstr(&user_path, home);
 659#ifdef GIT_WINDOWS_NATIVE
 660                        convert_slashes(user_path.buf);
 661#endif
 662                } else {
 663                        struct passwd *pw = getpw_str(username, username_len);
 664                        if (!pw)
 665                                goto return_null;
 666                        strbuf_addstr(&user_path, pw->pw_dir);
 667                }
 668                to_copy = first_slash;
 669        }
 670        strbuf_addstr(&user_path, to_copy);
 671        return strbuf_detach(&user_path, NULL);
 672return_null:
 673        strbuf_release(&user_path);
 674        return NULL;
 675}
 676
 677/*
 678 * First, one directory to try is determined by the following algorithm.
 679 *
 680 * (0) If "strict" is given, the path is used as given and no DWIM is
 681 *     done. Otherwise:
 682 * (1) "~/path" to mean path under the running user's home directory;
 683 * (2) "~user/path" to mean path under named user's home directory;
 684 * (3) "relative/path" to mean cwd relative directory; or
 685 * (4) "/absolute/path" to mean absolute directory.
 686 *
 687 * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
 688 * in this order. We select the first one that is a valid git repository, and
 689 * chdir() to it. If none match, or we fail to chdir, we return NULL.
 690 *
 691 * If all goes well, we return the directory we used to chdir() (but
 692 * before ~user is expanded), avoiding getcwd() resolving symbolic
 693 * links.  User relative paths are also returned as they are given,
 694 * except DWIM suffixing.
 695 */
 696const char *enter_repo(const char *path, int strict)
 697{
 698        static struct strbuf validated_path = STRBUF_INIT;
 699        static struct strbuf used_path = STRBUF_INIT;
 700
 701        if (!path)
 702                return NULL;
 703
 704        if (!strict) {
 705                static const char *suffix[] = {
 706                        "/.git", "", ".git/.git", ".git", NULL,
 707                };
 708                const char *gitfile;
 709                int len = strlen(path);
 710                int i;
 711                while ((1 < len) && (path[len-1] == '/'))
 712                        len--;
 713
 714                /*
 715                 * We can handle arbitrary-sized buffers, but this remains as a
 716                 * sanity check on untrusted input.
 717                 */
 718                if (PATH_MAX <= len)
 719                        return NULL;
 720
 721                strbuf_reset(&used_path);
 722                strbuf_reset(&validated_path);
 723                strbuf_add(&used_path, path, len);
 724                strbuf_add(&validated_path, path, len);
 725
 726                if (used_path.buf[0] == '~') {
 727                        char *newpath = expand_user_path(used_path.buf, 0);
 728                        if (!newpath)
 729                                return NULL;
 730                        strbuf_attach(&used_path, newpath, strlen(newpath),
 731                                      strlen(newpath));
 732                }
 733                for (i = 0; suffix[i]; i++) {
 734                        struct stat st;
 735                        size_t baselen = used_path.len;
 736                        strbuf_addstr(&used_path, suffix[i]);
 737                        if (!stat(used_path.buf, &st) &&
 738                            (S_ISREG(st.st_mode) ||
 739                            (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
 740                                strbuf_addstr(&validated_path, suffix[i]);
 741                                break;
 742                        }
 743                        strbuf_setlen(&used_path, baselen);
 744                }
 745                if (!suffix[i])
 746                        return NULL;
 747                gitfile = read_gitfile(used_path.buf);
 748                if (gitfile) {
 749                        strbuf_reset(&used_path);
 750                        strbuf_addstr(&used_path, gitfile);
 751                }
 752                if (chdir(used_path.buf))
 753                        return NULL;
 754                path = validated_path.buf;
 755        }
 756        else {
 757                const char *gitfile = read_gitfile(path);
 758                if (gitfile)
 759                        path = gitfile;
 760                if (chdir(path))
 761                        return NULL;
 762        }
 763
 764        if (is_git_directory(".")) {
 765                set_git_dir(".");
 766                check_repository_format();
 767                return path;
 768        }
 769
 770        return NULL;
 771}
 772
 773static int calc_shared_perm(int mode)
 774{
 775        int tweak;
 776
 777        if (get_shared_repository() < 0)
 778                tweak = -get_shared_repository();
 779        else
 780                tweak = get_shared_repository();
 781
 782        if (!(mode & S_IWUSR))
 783                tweak &= ~0222;
 784        if (mode & S_IXUSR)
 785                /* Copy read bits to execute bits */
 786                tweak |= (tweak & 0444) >> 2;
 787        if (get_shared_repository() < 0)
 788                mode = (mode & ~0777) | tweak;
 789        else
 790                mode |= tweak;
 791
 792        return mode;
 793}
 794
 795
 796int adjust_shared_perm(const char *path)
 797{
 798        int old_mode, new_mode;
 799
 800        if (!get_shared_repository())
 801                return 0;
 802        if (get_st_mode_bits(path, &old_mode) < 0)
 803                return -1;
 804
 805        new_mode = calc_shared_perm(old_mode);
 806        if (S_ISDIR(old_mode)) {
 807                /* Copy read bits to execute bits */
 808                new_mode |= (new_mode & 0444) >> 2;
 809                new_mode |= FORCE_DIR_SET_GID;
 810        }
 811
 812        if (((old_mode ^ new_mode) & ~S_IFMT) &&
 813                        chmod(path, (new_mode & ~S_IFMT)) < 0)
 814                return -2;
 815        return 0;
 816}
 817
 818void safe_create_dir(const char *dir, int share)
 819{
 820        if (mkdir(dir, 0777) < 0) {
 821                if (errno != EEXIST) {
 822                        perror(dir);
 823                        exit(1);
 824                }
 825        }
 826        else if (share && adjust_shared_perm(dir))
 827                die(_("Could not make %s writable by group"), dir);
 828}
 829
 830static int have_same_root(const char *path1, const char *path2)
 831{
 832        int is_abs1, is_abs2;
 833
 834        is_abs1 = is_absolute_path(path1);
 835        is_abs2 = is_absolute_path(path2);
 836        return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
 837               (!is_abs1 && !is_abs2);
 838}
 839
 840/*
 841 * Give path as relative to prefix.
 842 *
 843 * The strbuf may or may not be used, so do not assume it contains the
 844 * returned path.
 845 */
 846const char *relative_path(const char *in, const char *prefix,
 847                          struct strbuf *sb)
 848{
 849        int in_len = in ? strlen(in) : 0;
 850        int prefix_len = prefix ? strlen(prefix) : 0;
 851        int in_off = 0;
 852        int prefix_off = 0;
 853        int i = 0, j = 0;
 854
 855        if (!in_len)
 856                return "./";
 857        else if (!prefix_len)
 858                return in;
 859
 860        if (have_same_root(in, prefix))
 861                /* bypass dos_drive, for "c:" is identical to "C:" */
 862                i = j = has_dos_drive_prefix(in);
 863        else {
 864                return in;
 865        }
 866
 867        while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
 868                if (is_dir_sep(prefix[i])) {
 869                        while (is_dir_sep(prefix[i]))
 870                                i++;
 871                        while (is_dir_sep(in[j]))
 872                                j++;
 873                        prefix_off = i;
 874                        in_off = j;
 875                } else {
 876                        i++;
 877                        j++;
 878                }
 879        }
 880
 881        if (
 882            /* "prefix" seems like prefix of "in" */
 883            i >= prefix_len &&
 884            /*
 885             * but "/foo" is not a prefix of "/foobar"
 886             * (i.e. prefix not end with '/')
 887             */
 888            prefix_off < prefix_len) {
 889                if (j >= in_len) {
 890                        /* in="/a/b", prefix="/a/b" */
 891                        in_off = in_len;
 892                } else if (is_dir_sep(in[j])) {
 893                        /* in="/a/b/c", prefix="/a/b" */
 894                        while (is_dir_sep(in[j]))
 895                                j++;
 896                        in_off = j;
 897                } else {
 898                        /* in="/a/bbb/c", prefix="/a/b" */
 899                        i = prefix_off;
 900                }
 901        } else if (
 902                   /* "in" is short than "prefix" */
 903                   j >= in_len &&
 904                   /* "in" not end with '/' */
 905                   in_off < in_len) {
 906                if (is_dir_sep(prefix[i])) {
 907                        /* in="/a/b", prefix="/a/b/c/" */
 908                        while (is_dir_sep(prefix[i]))
 909                                i++;
 910                        in_off = in_len;
 911                }
 912        }
 913        in += in_off;
 914        in_len -= in_off;
 915
 916        if (i >= prefix_len) {
 917                if (!in_len)
 918                        return "./";
 919                else
 920                        return in;
 921        }
 922
 923        strbuf_reset(sb);
 924        strbuf_grow(sb, in_len);
 925
 926        while (i < prefix_len) {
 927                if (is_dir_sep(prefix[i])) {
 928                        strbuf_addstr(sb, "../");
 929                        while (is_dir_sep(prefix[i]))
 930                                i++;
 931                        continue;
 932                }
 933                i++;
 934        }
 935        if (!is_dir_sep(prefix[prefix_len - 1]))
 936                strbuf_addstr(sb, "../");
 937
 938        strbuf_addstr(sb, in);
 939
 940        return sb->buf;
 941}
 942
 943/*
 944 * A simpler implementation of relative_path
 945 *
 946 * Get relative path by removing "prefix" from "in". This function
 947 * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
 948 * to increase performance when traversing the path to work_tree.
 949 */
 950const char *remove_leading_path(const char *in, const char *prefix)
 951{
 952        static struct strbuf buf = STRBUF_INIT;
 953        int i = 0, j = 0;
 954
 955        if (!prefix || !prefix[0])
 956                return in;
 957        while (prefix[i]) {
 958                if (is_dir_sep(prefix[i])) {
 959                        if (!is_dir_sep(in[j]))
 960                                return in;
 961                        while (is_dir_sep(prefix[i]))
 962                                i++;
 963                        while (is_dir_sep(in[j]))
 964                                j++;
 965                        continue;
 966                } else if (in[j] != prefix[i]) {
 967                        return in;
 968                }
 969                i++;
 970                j++;
 971        }
 972        if (
 973            /* "/foo" is a prefix of "/foo" */
 974            in[j] &&
 975            /* "/foo" is not a prefix of "/foobar" */
 976            !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
 977           )
 978                return in;
 979        while (is_dir_sep(in[j]))
 980                j++;
 981
 982        strbuf_reset(&buf);
 983        if (!in[j])
 984                strbuf_addstr(&buf, ".");
 985        else
 986                strbuf_addstr(&buf, in + j);
 987        return buf.buf;
 988}
 989
 990/*
 991 * It is okay if dst == src, but they should not overlap otherwise.
 992 *
 993 * Performs the following normalizations on src, storing the result in dst:
 994 * - Ensures that components are separated by '/' (Windows only)
 995 * - Squashes sequences of '/' except "//server/share" on Windows
 996 * - Removes "." components.
 997 * - Removes ".." components, and the components the precede them.
 998 * Returns failure (non-zero) if a ".." component appears as first path
 999 * component anytime during the normalization. Otherwise, returns success (0).
1000 *
1001 * Note that this function is purely textual.  It does not follow symlinks,
1002 * verify the existence of the path, or make any system calls.
1003 *
1004 * prefix_len != NULL is for a specific case of prefix_pathspec():
1005 * assume that src == dst and src[0..prefix_len-1] is already
1006 * normalized, any time "../" eats up to the prefix_len part,
1007 * prefix_len is reduced. In the end prefix_len is the remaining
1008 * prefix that has not been overridden by user pathspec.
1009 *
1010 * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
1011 * For everything but the root folder itself, the normalized path should not
1012 * end with a '/', then the callers need to be fixed up accordingly.
1013 *
1014 */
1015int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
1016{
1017        char *dst0;
1018        const char *end;
1019
1020        /*
1021         * Copy initial part of absolute path: "/", "C:/", "//server/share/".
1022         */
1023        end = src + offset_1st_component(src);
1024        while (src < end) {
1025                char c = *src++;
1026                if (is_dir_sep(c))
1027                        c = '/';
1028                *dst++ = c;
1029        }
1030        dst0 = dst;
1031
1032        while (is_dir_sep(*src))
1033                src++;
1034
1035        for (;;) {
1036                char c = *src;
1037
1038                /*
1039                 * A path component that begins with . could be
1040                 * special:
1041                 * (1) "." and ends   -- ignore and terminate.
1042                 * (2) "./"           -- ignore them, eat slash and continue.
1043                 * (3) ".." and ends  -- strip one and terminate.
1044                 * (4) "../"          -- strip one, eat slash and continue.
1045                 */
1046                if (c == '.') {
1047                        if (!src[1]) {
1048                                /* (1) */
1049                                src++;
1050                        } else if (is_dir_sep(src[1])) {
1051                                /* (2) */
1052                                src += 2;
1053                                while (is_dir_sep(*src))
1054                                        src++;
1055                                continue;
1056                        } else if (src[1] == '.') {
1057                                if (!src[2]) {
1058                                        /* (3) */
1059                                        src += 2;
1060                                        goto up_one;
1061                                } else if (is_dir_sep(src[2])) {
1062                                        /* (4) */
1063                                        src += 3;
1064                                        while (is_dir_sep(*src))
1065                                                src++;
1066                                        goto up_one;
1067                                }
1068                        }
1069                }
1070
1071                /* copy up to the next '/', and eat all '/' */
1072                while ((c = *src++) != '\0' && !is_dir_sep(c))
1073                        *dst++ = c;
1074                if (is_dir_sep(c)) {
1075                        *dst++ = '/';
1076                        while (is_dir_sep(c))
1077                                c = *src++;
1078                        src--;
1079                } else if (!c)
1080                        break;
1081                continue;
1082
1083        up_one:
1084                /*
1085                 * dst0..dst is prefix portion, and dst[-1] is '/';
1086                 * go up one level.
1087                 */
1088                dst--;  /* go to trailing '/' */
1089                if (dst <= dst0)
1090                        return -1;
1091                /* Windows: dst[-1] cannot be backslash anymore */
1092                while (dst0 < dst && dst[-1] != '/')
1093                        dst--;
1094                if (prefix_len && *prefix_len > dst - dst0)
1095                        *prefix_len = dst - dst0;
1096        }
1097        *dst = '\0';
1098        return 0;
1099}
1100
1101int normalize_path_copy(char *dst, const char *src)
1102{
1103        return normalize_path_copy_len(dst, src, NULL);
1104}
1105
1106/*
1107 * path = Canonical absolute path
1108 * prefixes = string_list containing normalized, absolute paths without
1109 * trailing slashes (except for the root directory, which is denoted by "/").
1110 *
1111 * Determines, for each path in prefixes, whether the "prefix"
1112 * is an ancestor directory of path.  Returns the length of the longest
1113 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1114 * is an ancestor.  (Note that this means 0 is returned if prefixes is
1115 * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1116 * are not considered to be their own ancestors.  path must be in a
1117 * canonical form: empty components, or "." or ".." components are not
1118 * allowed.
1119 */
1120int longest_ancestor_length(const char *path, struct string_list *prefixes)
1121{
1122        int i, max_len = -1;
1123
1124        if (!strcmp(path, "/"))
1125                return -1;
1126
1127        for (i = 0; i < prefixes->nr; i++) {
1128                const char *ceil = prefixes->items[i].string;
1129                int len = strlen(ceil);
1130
1131                if (len == 1 && ceil[0] == '/')
1132                        len = 0; /* root matches anything, with length 0 */
1133                else if (!strncmp(path, ceil, len) && path[len] == '/')
1134                        ; /* match of length len */
1135                else
1136                        continue; /* no match */
1137
1138                if (len > max_len)
1139                        max_len = len;
1140        }
1141
1142        return max_len;
1143}
1144
1145/* strip arbitrary amount of directory separators at end of path */
1146static inline int chomp_trailing_dir_sep(const char *path, int len)
1147{
1148        while (len && is_dir_sep(path[len - 1]))
1149                len--;
1150        return len;
1151}
1152
1153/*
1154 * If path ends with suffix (complete path components), returns the
1155 * part before suffix (sans trailing directory separators).
1156 * Otherwise returns NULL.
1157 */
1158char *strip_path_suffix(const char *path, const char *suffix)
1159{
1160        int path_len = strlen(path), suffix_len = strlen(suffix);
1161
1162        while (suffix_len) {
1163                if (!path_len)
1164                        return NULL;
1165
1166                if (is_dir_sep(path[path_len - 1])) {
1167                        if (!is_dir_sep(suffix[suffix_len - 1]))
1168                                return NULL;
1169                        path_len = chomp_trailing_dir_sep(path, path_len);
1170                        suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
1171                }
1172                else if (path[--path_len] != suffix[--suffix_len])
1173                        return NULL;
1174        }
1175
1176        if (path_len && !is_dir_sep(path[path_len - 1]))
1177                return NULL;
1178        return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
1179}
1180
1181int daemon_avoid_alias(const char *p)
1182{
1183        int sl, ndot;
1184
1185        /*
1186         * This resurrects the belts and suspenders paranoia check by HPA
1187         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
1188         * does not do getcwd() based path canonicalization.
1189         *
1190         * sl becomes true immediately after seeing '/' and continues to
1191         * be true as long as dots continue after that without intervening
1192         * non-dot character.
1193         */
1194        if (!p || (*p != '/' && *p != '~'))
1195                return -1;
1196        sl = 1; ndot = 0;
1197        p++;
1198
1199        while (1) {
1200                char ch = *p++;
1201                if (sl) {
1202                        if (ch == '.')
1203                                ndot++;
1204                        else if (ch == '/') {
1205                                if (ndot < 3)
1206                                        /* reject //, /./ and /../ */
1207                                        return -1;
1208                                ndot = 0;
1209                        }
1210                        else if (ch == 0) {
1211                                if (0 < ndot && ndot < 3)
1212                                        /* reject /.$ and /..$ */
1213                                        return -1;
1214                                return 0;
1215                        }
1216                        else
1217                                sl = ndot = 0;
1218                }
1219                else if (ch == 0)
1220                        return 0;
1221                else if (ch == '/') {
1222                        sl = 1;
1223                        ndot = 0;
1224                }
1225        }
1226}
1227
1228static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
1229{
1230        if (len < skip)
1231                return 0;
1232        len -= skip;
1233        path += skip;
1234        while (len-- > 0) {
1235                char c = *(path++);
1236                if (c != ' ' && c != '.')
1237                        return 0;
1238        }
1239        return 1;
1240}
1241
1242int is_ntfs_dotgit(const char *name)
1243{
1244        int len;
1245
1246        for (len = 0; ; len++)
1247                if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
1248                        if (only_spaces_and_periods(name, len, 4) &&
1249                                        !strncasecmp(name, ".git", 4))
1250                                return 1;
1251                        if (only_spaces_and_periods(name, len, 5) &&
1252                                        !strncasecmp(name, "git~1", 5))
1253                                return 1;
1254                        if (name[len] != '\\')
1255                                return 0;
1256                        name += len + 1;
1257                        len = -1;
1258                }
1259}
1260
1261char *xdg_config_home(const char *filename)
1262{
1263        const char *home, *config_home;
1264
1265        assert(filename);
1266        config_home = getenv("XDG_CONFIG_HOME");
1267        if (config_home && *config_home)
1268                return mkpathdup("%s/git/%s", config_home, filename);
1269
1270        home = getenv("HOME");
1271        if (home)
1272                return mkpathdup("%s/.config/git/%s", home, filename);
1273        return NULL;
1274}
1275
1276char *xdg_cache_home(const char *filename)
1277{
1278        const char *home, *cache_home;
1279
1280        assert(filename);
1281        cache_home = getenv("XDG_CACHE_HOME");
1282        if (cache_home && *cache_home)
1283                return mkpathdup("%s/git/%s", cache_home, filename);
1284
1285        home = getenv("HOME");
1286        if (home)
1287                return mkpathdup("%s/.cache/git/%s", home, filename);
1288        return NULL;
1289}
1290
1291GIT_PATH_FUNC(git_path_cherry_pick_head, "CHERRY_PICK_HEAD")
1292GIT_PATH_FUNC(git_path_revert_head, "REVERT_HEAD")
1293GIT_PATH_FUNC(git_path_squash_msg, "SQUASH_MSG")
1294GIT_PATH_FUNC(git_path_merge_msg, "MERGE_MSG")
1295GIT_PATH_FUNC(git_path_merge_rr, "MERGE_RR")
1296GIT_PATH_FUNC(git_path_merge_mode, "MERGE_MODE")
1297GIT_PATH_FUNC(git_path_merge_head, "MERGE_HEAD")
1298GIT_PATH_FUNC(git_path_fetch_head, "FETCH_HEAD")
1299GIT_PATH_FUNC(git_path_shallow, "shallow")