path.con commit Merge branch 'jk/t4205-cleanup' (4d7f59a)
   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#include "worktree.h"
   9
  10static int get_st_mode_bits(const char *path, int *mode)
  11{
  12        struct stat st;
  13        if (lstat(path, &st) < 0)
  14                return -1;
  15        *mode = st.st_mode;
  16        return 0;
  17}
  18
  19static char bad_path[] = "/bad-path/";
  20
  21static struct strbuf *get_pathname(void)
  22{
  23        static struct strbuf pathname_array[4] = {
  24                STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
  25        };
  26        static int index;
  27        struct strbuf *sb = &pathname_array[3 & ++index];
  28        strbuf_reset(sb);
  29        return sb;
  30}
  31
  32static char *cleanup_path(char *path)
  33{
  34        /* Clean it up */
  35        if (!memcmp(path, "./", 2)) {
  36                path += 2;
  37                while (*path == '/')
  38                        path++;
  39        }
  40        return path;
  41}
  42
  43static void strbuf_cleanup_path(struct strbuf *sb)
  44{
  45        char *path = cleanup_path(sb->buf);
  46        if (path > sb->buf)
  47                strbuf_remove(sb, 0, path - sb->buf);
  48}
  49
  50char *mksnpath(char *buf, size_t n, const char *fmt, ...)
  51{
  52        va_list args;
  53        unsigned len;
  54
  55        va_start(args, fmt);
  56        len = vsnprintf(buf, n, fmt, args);
  57        va_end(args);
  58        if (len >= n) {
  59                strlcpy(buf, bad_path, n);
  60                return buf;
  61        }
  62        return cleanup_path(buf);
  63}
  64
  65static int dir_prefix(const char *buf, const char *dir)
  66{
  67        int len = strlen(dir);
  68        return !strncmp(buf, dir, len) &&
  69                (is_dir_sep(buf[len]) || buf[len] == '\0');
  70}
  71
  72/* $buf =~ m|$dir/+$file| but without regex */
  73static int is_dir_file(const char *buf, const char *dir, const char *file)
  74{
  75        int len = strlen(dir);
  76        if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
  77                return 0;
  78        while (is_dir_sep(buf[len]))
  79                len++;
  80        return !strcmp(buf + len, file);
  81}
  82
  83static void replace_dir(struct strbuf *buf, int len, const char *newdir)
  84{
  85        int newlen = strlen(newdir);
  86        int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
  87                !is_dir_sep(newdir[newlen - 1]);
  88        if (need_sep)
  89                len--;   /* keep one char, to be replaced with '/'  */
  90        strbuf_splice(buf, 0, len, newdir, newlen);
  91        if (need_sep)
  92                buf->buf[newlen] = '/';
  93}
  94
  95struct common_dir {
  96        /* Not considered garbage for report_linked_checkout_garbage */
  97        unsigned ignore_garbage:1;
  98        unsigned is_dir:1;
  99        /* Not common even though its parent is */
 100        unsigned exclude:1;
 101        const char *dirname;
 102};
 103
 104static struct common_dir common_list[] = {
 105        { 0, 1, 0, "branches" },
 106        { 0, 1, 0, "hooks" },
 107        { 0, 1, 0, "info" },
 108        { 0, 0, 1, "info/sparse-checkout" },
 109        { 1, 1, 0, "logs" },
 110        { 1, 1, 1, "logs/HEAD" },
 111        { 0, 1, 1, "logs/refs/bisect" },
 112        { 0, 1, 0, "lost-found" },
 113        { 0, 1, 0, "objects" },
 114        { 0, 1, 0, "refs" },
 115        { 0, 1, 1, "refs/bisect" },
 116        { 0, 1, 0, "remotes" },
 117        { 0, 1, 0, "worktrees" },
 118        { 0, 1, 0, "rr-cache" },
 119        { 0, 1, 0, "svn" },
 120        { 0, 0, 0, "config" },
 121        { 1, 0, 0, "gc.pid" },
 122        { 0, 0, 0, "packed-refs" },
 123        { 0, 0, 0, "shallow" },
 124        { 0, 0, 0, NULL }
 125};
 126
 127/*
 128 * A compressed trie.  A trie node consists of zero or more characters that
 129 * are common to all elements with this prefix, optionally followed by some
 130 * children.  If value is not NULL, the trie node is a terminal node.
 131 *
 132 * For example, consider the following set of strings:
 133 * abc
 134 * def
 135 * definite
 136 * definition
 137 *
 138 * The trie would look like:
 139 * root: len = 0, children a and d non-NULL, value = NULL.
 140 *    a: len = 2, contents = bc, value = (data for "abc")
 141 *    d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
 142 *       i: len = 3, contents = nit, children e and i non-NULL, value = NULL
 143 *           e: len = 0, children all NULL, value = (data for "definite")
 144 *           i: len = 2, contents = on, children all NULL,
 145 *              value = (data for "definition")
 146 */
 147struct trie {
 148        struct trie *children[256];
 149        int len;
 150        char *contents;
 151        void *value;
 152};
 153
 154static struct trie *make_trie_node(const char *key, void *value)
 155{
 156        struct trie *new_node = xcalloc(1, sizeof(*new_node));
 157        new_node->len = strlen(key);
 158        if (new_node->len) {
 159                new_node->contents = xmalloc(new_node->len);
 160                memcpy(new_node->contents, key, new_node->len);
 161        }
 162        new_node->value = value;
 163        return new_node;
 164}
 165
 166/*
 167 * Add a key/value pair to a trie.  The key is assumed to be \0-terminated.
 168 * If there was an existing value for this key, return it.
 169 */
 170static void *add_to_trie(struct trie *root, const char *key, void *value)
 171{
 172        struct trie *child;
 173        void *old;
 174        int i;
 175
 176        if (!*key) {
 177                /* we have reached the end of the key */
 178                old = root->value;
 179                root->value = value;
 180                return old;
 181        }
 182
 183        for (i = 0; i < root->len; i++) {
 184                if (root->contents[i] == key[i])
 185                        continue;
 186
 187                /*
 188                 * Split this node: child will contain this node's
 189                 * existing children.
 190                 */
 191                child = malloc(sizeof(*child));
 192                memcpy(child->children, root->children, sizeof(root->children));
 193
 194                child->len = root->len - i - 1;
 195                if (child->len) {
 196                        child->contents = xstrndup(root->contents + i + 1,
 197                                                   child->len);
 198                }
 199                child->value = root->value;
 200                root->value = NULL;
 201                root->len = i;
 202
 203                memset(root->children, 0, sizeof(root->children));
 204                root->children[(unsigned char)root->contents[i]] = child;
 205
 206                /* This is the newly-added child. */
 207                root->children[(unsigned char)key[i]] =
 208                        make_trie_node(key + i + 1, value);
 209                return NULL;
 210        }
 211
 212        /* We have matched the entire compressed section */
 213        if (key[i]) {
 214                child = root->children[(unsigned char)key[root->len]];
 215                if (child) {
 216                        return add_to_trie(child, key + root->len + 1, value);
 217                } else {
 218                        child = make_trie_node(key + root->len + 1, value);
 219                        root->children[(unsigned char)key[root->len]] = child;
 220                        return NULL;
 221                }
 222        }
 223
 224        old = root->value;
 225        root->value = value;
 226        return old;
 227}
 228
 229typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
 230
 231/*
 232 * Search a trie for some key.  Find the longest /-or-\0-terminated
 233 * prefix of the key for which the trie contains a value.  Call fn
 234 * with the unmatched portion of the key and the found value, and
 235 * return its return value.  If there is no such prefix, return -1.
 236 *
 237 * The key is partially normalized: consecutive slashes are skipped.
 238 *
 239 * For example, consider the trie containing only [refs,
 240 * refs/worktree] (both with values).
 241 *
 242 * | key             | unmatched  | val from node | return value |
 243 * |-----------------|------------|---------------|--------------|
 244 * | a               | not called | n/a           | -1           |
 245 * | refs            | \0         | refs          | as per fn    |
 246 * | refs/           | /          | refs          | as per fn    |
 247 * | refs/w          | /w         | refs          | as per fn    |
 248 * | refs/worktree   | \0         | refs/worktree | as per fn    |
 249 * | refs/worktree/  | /          | refs/worktree | as per fn    |
 250 * | refs/worktree/a | /a         | refs/worktree | as per fn    |
 251 * |-----------------|------------|---------------|--------------|
 252 *
 253 */
 254static int trie_find(struct trie *root, const char *key, match_fn fn,
 255                     void *baton)
 256{
 257        int i;
 258        int result;
 259        struct trie *child;
 260
 261        if (!*key) {
 262                /* we have reached the end of the key */
 263                if (root->value && !root->len)
 264                        return fn(key, root->value, baton);
 265                else
 266                        return -1;
 267        }
 268
 269        for (i = 0; i < root->len; i++) {
 270                /* Partial path normalization: skip consecutive slashes. */
 271                if (key[i] == '/' && key[i+1] == '/') {
 272                        key++;
 273                        continue;
 274                }
 275                if (root->contents[i] != key[i])
 276                        return -1;
 277        }
 278
 279        /* Matched the entire compressed section */
 280        key += i;
 281        if (!*key)
 282                /* End of key */
 283                return fn(key, root->value, baton);
 284
 285        /* Partial path normalization: skip consecutive slashes */
 286        while (key[0] == '/' && key[1] == '/')
 287                key++;
 288
 289        child = root->children[(unsigned char)*key];
 290        if (child)
 291                result = trie_find(child, key + 1, fn, baton);
 292        else
 293                result = -1;
 294
 295        if (result >= 0 || (*key != '/' && *key != 0))
 296                return result;
 297        if (root->value)
 298                return fn(key, root->value, baton);
 299        else
 300                return -1;
 301}
 302
 303static struct trie common_trie;
 304static int common_trie_done_setup;
 305
 306static void init_common_trie(void)
 307{
 308        struct common_dir *p;
 309
 310        if (common_trie_done_setup)
 311                return;
 312
 313        for (p = common_list; p->dirname; p++)
 314                add_to_trie(&common_trie, p->dirname, p);
 315
 316        common_trie_done_setup = 1;
 317}
 318
 319/*
 320 * Helper function for update_common_dir: returns 1 if the dir
 321 * prefix is common.
 322 */
 323static int check_common(const char *unmatched, void *value, void *baton)
 324{
 325        struct common_dir *dir = value;
 326
 327        if (!dir)
 328                return 0;
 329
 330        if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
 331                return !dir->exclude;
 332
 333        if (!dir->is_dir && unmatched[0] == 0)
 334                return !dir->exclude;
 335
 336        return 0;
 337}
 338
 339static void update_common_dir(struct strbuf *buf, int git_dir_len,
 340                              const char *common_dir)
 341{
 342        char *base = buf->buf + git_dir_len;
 343        init_common_trie();
 344        if (!common_dir)
 345                common_dir = get_git_common_dir();
 346        if (trie_find(&common_trie, base, check_common, NULL) > 0)
 347                replace_dir(buf, git_dir_len, common_dir);
 348}
 349
 350void report_linked_checkout_garbage(void)
 351{
 352        struct strbuf sb = STRBUF_INIT;
 353        const struct common_dir *p;
 354        int len;
 355
 356        if (!git_common_dir_env)
 357                return;
 358        strbuf_addf(&sb, "%s/", get_git_dir());
 359        len = sb.len;
 360        for (p = common_list; p->dirname; p++) {
 361                const char *path = p->dirname;
 362                if (p->ignore_garbage)
 363                        continue;
 364                strbuf_setlen(&sb, len);
 365                strbuf_addstr(&sb, path);
 366                if (file_exists(sb.buf))
 367                        report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
 368        }
 369        strbuf_release(&sb);
 370}
 371
 372static void adjust_git_path(struct strbuf *buf, int git_dir_len)
 373{
 374        const char *base = buf->buf + git_dir_len;
 375        if (git_graft_env && is_dir_file(base, "info", "grafts"))
 376                strbuf_splice(buf, 0, buf->len,
 377                              get_graft_file(), strlen(get_graft_file()));
 378        else if (git_index_env && !strcmp(base, "index"))
 379                strbuf_splice(buf, 0, buf->len,
 380                              get_index_file(), strlen(get_index_file()));
 381        else if (git_db_env && dir_prefix(base, "objects"))
 382                replace_dir(buf, git_dir_len + 7, get_object_directory());
 383        else if (git_common_dir_env)
 384                update_common_dir(buf, git_dir_len, NULL);
 385}
 386
 387static void do_git_path(const struct worktree *wt, struct strbuf *buf,
 388                        const char *fmt, va_list args)
 389{
 390        int gitdir_len;
 391        strbuf_addstr(buf, get_worktree_git_dir(wt));
 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
 400char *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(NULL, buf, fmt, args);
 406        va_end(args);
 407        return buf->buf;
 408}
 409
 410void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 411{
 412        va_list args;
 413        va_start(args, fmt);
 414        do_git_path(NULL, sb, fmt, args);
 415        va_end(args);
 416}
 417
 418const 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(NULL, pathname, fmt, args);
 424        va_end(args);
 425        return pathname->buf;
 426}
 427
 428char *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(NULL, &path, fmt, args);
 434        va_end(args);
 435        return strbuf_detach(&path, NULL);
 436}
 437
 438char *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
 449const 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
 459const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 460{
 461        struct strbuf *pathname = get_pathname();
 462        va_list args;
 463        va_start(args, fmt);
 464        do_git_path(wt, pathname, fmt, args);
 465        va_end(args);
 466        return pathname->buf;
 467}
 468
 469static void do_submodule_path(struct strbuf *buf, const char *path,
 470                              const char *fmt, va_list args)
 471{
 472        const char *git_dir;
 473        struct strbuf git_submodule_common_dir = STRBUF_INIT;
 474        struct strbuf git_submodule_dir = STRBUF_INIT;
 475
 476        strbuf_addstr(buf, path);
 477        strbuf_complete(buf, '/');
 478        strbuf_addstr(buf, ".git");
 479
 480        git_dir = read_gitfile(buf->buf);
 481        if (git_dir) {
 482                strbuf_reset(buf);
 483                strbuf_addstr(buf, git_dir);
 484        }
 485        strbuf_addch(buf, '/');
 486        strbuf_addbuf(&git_submodule_dir, buf);
 487
 488        strbuf_vaddf(buf, fmt, args);
 489
 490        if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
 491                update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
 492
 493        strbuf_cleanup_path(buf);
 494
 495        strbuf_release(&git_submodule_dir);
 496        strbuf_release(&git_submodule_common_dir);
 497}
 498
 499char *git_pathdup_submodule(const char *path, const char *fmt, ...)
 500{
 501        va_list args;
 502        struct strbuf buf = STRBUF_INIT;
 503        va_start(args, fmt);
 504        do_submodule_path(&buf, path, fmt, args);
 505        va_end(args);
 506        return strbuf_detach(&buf, NULL);
 507}
 508
 509void strbuf_git_path_submodule(struct strbuf *buf, const char *path,
 510                               const char *fmt, ...)
 511{
 512        va_list args;
 513        va_start(args, fmt);
 514        do_submodule_path(buf, path, fmt, args);
 515        va_end(args);
 516}
 517
 518static void do_git_common_path(struct strbuf *buf,
 519                               const char *fmt,
 520                               va_list args)
 521{
 522        strbuf_addstr(buf, get_git_common_dir());
 523        if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 524                strbuf_addch(buf, '/');
 525        strbuf_vaddf(buf, fmt, args);
 526        strbuf_cleanup_path(buf);
 527}
 528
 529const char *git_common_path(const char *fmt, ...)
 530{
 531        struct strbuf *pathname = get_pathname();
 532        va_list args;
 533        va_start(args, fmt);
 534        do_git_common_path(pathname, fmt, args);
 535        va_end(args);
 536        return pathname->buf;
 537}
 538
 539void strbuf_git_common_path(struct strbuf *sb, const char *fmt, ...)
 540{
 541        va_list args;
 542        va_start(args, fmt);
 543        do_git_common_path(sb, fmt, args);
 544        va_end(args);
 545}
 546
 547int validate_headref(const char *path)
 548{
 549        struct stat st;
 550        char *buf, buffer[256];
 551        unsigned char sha1[20];
 552        int fd;
 553        ssize_t len;
 554
 555        if (lstat(path, &st) < 0)
 556                return -1;
 557
 558        /* Make sure it is a "refs/.." symlink */
 559        if (S_ISLNK(st.st_mode)) {
 560                len = readlink(path, buffer, sizeof(buffer)-1);
 561                if (len >= 5 && !memcmp("refs/", buffer, 5))
 562                        return 0;
 563                return -1;
 564        }
 565
 566        /*
 567         * Anything else, just open it and try to see if it is a symbolic ref.
 568         */
 569        fd = open(path, O_RDONLY);
 570        if (fd < 0)
 571                return -1;
 572        len = read_in_full(fd, buffer, sizeof(buffer)-1);
 573        close(fd);
 574
 575        /*
 576         * Is it a symbolic ref?
 577         */
 578        if (len < 4)
 579                return -1;
 580        if (!memcmp("ref:", buffer, 4)) {
 581                buf = buffer + 4;
 582                len -= 4;
 583                while (len && isspace(*buf))
 584                        buf++, len--;
 585                if (len >= 5 && !memcmp("refs/", buf, 5))
 586                        return 0;
 587        }
 588
 589        /*
 590         * Is this a detached HEAD?
 591         */
 592        if (!get_sha1_hex(buffer, sha1))
 593                return 0;
 594
 595        return -1;
 596}
 597
 598static struct passwd *getpw_str(const char *username, size_t len)
 599{
 600        struct passwd *pw;
 601        char *username_z = xmemdupz(username, len);
 602        pw = getpwnam(username_z);
 603        free(username_z);
 604        return pw;
 605}
 606
 607/*
 608 * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
 609 * then it is a newly allocated string. Returns NULL on getpw failure or
 610 * if path is NULL.
 611 */
 612char *expand_user_path(const char *path)
 613{
 614        struct strbuf user_path = STRBUF_INIT;
 615        const char *to_copy = path;
 616
 617        if (path == NULL)
 618                goto return_null;
 619        if (path[0] == '~') {
 620                const char *first_slash = strchrnul(path, '/');
 621                const char *username = path + 1;
 622                size_t username_len = first_slash - username;
 623                if (username_len == 0) {
 624                        const char *home = getenv("HOME");
 625                        if (!home)
 626                                goto return_null;
 627                        strbuf_addstr(&user_path, home);
 628#ifdef GIT_WINDOWS_NATIVE
 629                        convert_slashes(user_path.buf);
 630#endif
 631                } else {
 632                        struct passwd *pw = getpw_str(username, username_len);
 633                        if (!pw)
 634                                goto return_null;
 635                        strbuf_addstr(&user_path, pw->pw_dir);
 636                }
 637                to_copy = first_slash;
 638        }
 639        strbuf_addstr(&user_path, to_copy);
 640        return strbuf_detach(&user_path, NULL);
 641return_null:
 642        strbuf_release(&user_path);
 643        return NULL;
 644}
 645
 646/*
 647 * First, one directory to try is determined by the following algorithm.
 648 *
 649 * (0) If "strict" is given, the path is used as given and no DWIM is
 650 *     done. Otherwise:
 651 * (1) "~/path" to mean path under the running user's home directory;
 652 * (2) "~user/path" to mean path under named user's home directory;
 653 * (3) "relative/path" to mean cwd relative directory; or
 654 * (4) "/absolute/path" to mean absolute directory.
 655 *
 656 * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
 657 * in this order. We select the first one that is a valid git repository, and
 658 * chdir() to it. If none match, or we fail to chdir, we return NULL.
 659 *
 660 * If all goes well, we return the directory we used to chdir() (but
 661 * before ~user is expanded), avoiding getcwd() resolving symbolic
 662 * links.  User relative paths are also returned as they are given,
 663 * except DWIM suffixing.
 664 */
 665const char *enter_repo(const char *path, int strict)
 666{
 667        static struct strbuf validated_path = STRBUF_INIT;
 668        static struct strbuf used_path = STRBUF_INIT;
 669
 670        if (!path)
 671                return NULL;
 672
 673        if (!strict) {
 674                static const char *suffix[] = {
 675                        "/.git", "", ".git/.git", ".git", NULL,
 676                };
 677                const char *gitfile;
 678                int len = strlen(path);
 679                int i;
 680                while ((1 < len) && (path[len-1] == '/'))
 681                        len--;
 682
 683                /*
 684                 * We can handle arbitrary-sized buffers, but this remains as a
 685                 * sanity check on untrusted input.
 686                 */
 687                if (PATH_MAX <= len)
 688                        return NULL;
 689
 690                strbuf_reset(&used_path);
 691                strbuf_reset(&validated_path);
 692                strbuf_add(&used_path, path, len);
 693                strbuf_add(&validated_path, path, len);
 694
 695                if (used_path.buf[0] == '~') {
 696                        char *newpath = expand_user_path(used_path.buf);
 697                        if (!newpath)
 698                                return NULL;
 699                        strbuf_attach(&used_path, newpath, strlen(newpath),
 700                                      strlen(newpath));
 701                }
 702                for (i = 0; suffix[i]; i++) {
 703                        struct stat st;
 704                        size_t baselen = used_path.len;
 705                        strbuf_addstr(&used_path, suffix[i]);
 706                        if (!stat(used_path.buf, &st) &&
 707                            (S_ISREG(st.st_mode) ||
 708                            (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
 709                                strbuf_addstr(&validated_path, suffix[i]);
 710                                break;
 711                        }
 712                        strbuf_setlen(&used_path, baselen);
 713                }
 714                if (!suffix[i])
 715                        return NULL;
 716                gitfile = read_gitfile(used_path.buf);
 717                if (gitfile) {
 718                        strbuf_reset(&used_path);
 719                        strbuf_addstr(&used_path, gitfile);
 720                }
 721                if (chdir(used_path.buf))
 722                        return NULL;
 723                path = validated_path.buf;
 724        }
 725        else {
 726                const char *gitfile = read_gitfile(path);
 727                if (gitfile)
 728                        path = gitfile;
 729                if (chdir(path))
 730                        return NULL;
 731        }
 732
 733        if (is_git_directory(".")) {
 734                set_git_dir(".");
 735                check_repository_format();
 736                return path;
 737        }
 738
 739        return NULL;
 740}
 741
 742static int calc_shared_perm(int mode)
 743{
 744        int tweak;
 745
 746        if (get_shared_repository() < 0)
 747                tweak = -get_shared_repository();
 748        else
 749                tweak = get_shared_repository();
 750
 751        if (!(mode & S_IWUSR))
 752                tweak &= ~0222;
 753        if (mode & S_IXUSR)
 754                /* Copy read bits to execute bits */
 755                tweak |= (tweak & 0444) >> 2;
 756        if (get_shared_repository() < 0)
 757                mode = (mode & ~0777) | tweak;
 758        else
 759                mode |= tweak;
 760
 761        return mode;
 762}
 763
 764
 765int adjust_shared_perm(const char *path)
 766{
 767        int old_mode, new_mode;
 768
 769        if (!get_shared_repository())
 770                return 0;
 771        if (get_st_mode_bits(path, &old_mode) < 0)
 772                return -1;
 773
 774        new_mode = calc_shared_perm(old_mode);
 775        if (S_ISDIR(old_mode)) {
 776                /* Copy read bits to execute bits */
 777                new_mode |= (new_mode & 0444) >> 2;
 778                new_mode |= FORCE_DIR_SET_GID;
 779        }
 780
 781        if (((old_mode ^ new_mode) & ~S_IFMT) &&
 782                        chmod(path, (new_mode & ~S_IFMT)) < 0)
 783                return -2;
 784        return 0;
 785}
 786
 787void safe_create_dir(const char *dir, int share)
 788{
 789        if (mkdir(dir, 0777) < 0) {
 790                if (errno != EEXIST) {
 791                        perror(dir);
 792                        exit(1);
 793                }
 794        }
 795        else if (share && adjust_shared_perm(dir))
 796                die(_("Could not make %s writable by group"), dir);
 797}
 798
 799static int have_same_root(const char *path1, const char *path2)
 800{
 801        int is_abs1, is_abs2;
 802
 803        is_abs1 = is_absolute_path(path1);
 804        is_abs2 = is_absolute_path(path2);
 805        return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
 806               (!is_abs1 && !is_abs2);
 807}
 808
 809/*
 810 * Give path as relative to prefix.
 811 *
 812 * The strbuf may or may not be used, so do not assume it contains the
 813 * returned path.
 814 */
 815const char *relative_path(const char *in, const char *prefix,
 816                          struct strbuf *sb)
 817{
 818        int in_len = in ? strlen(in) : 0;
 819        int prefix_len = prefix ? strlen(prefix) : 0;
 820        int in_off = 0;
 821        int prefix_off = 0;
 822        int i = 0, j = 0;
 823
 824        if (!in_len)
 825                return "./";
 826        else if (!prefix_len)
 827                return in;
 828
 829        if (have_same_root(in, prefix))
 830                /* bypass dos_drive, for "c:" is identical to "C:" */
 831                i = j = has_dos_drive_prefix(in);
 832        else {
 833                return in;
 834        }
 835
 836        while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
 837                if (is_dir_sep(prefix[i])) {
 838                        while (is_dir_sep(prefix[i]))
 839                                i++;
 840                        while (is_dir_sep(in[j]))
 841                                j++;
 842                        prefix_off = i;
 843                        in_off = j;
 844                } else {
 845                        i++;
 846                        j++;
 847                }
 848        }
 849
 850        if (
 851            /* "prefix" seems like prefix of "in" */
 852            i >= prefix_len &&
 853            /*
 854             * but "/foo" is not a prefix of "/foobar"
 855             * (i.e. prefix not end with '/')
 856             */
 857            prefix_off < prefix_len) {
 858                if (j >= in_len) {
 859                        /* in="/a/b", prefix="/a/b" */
 860                        in_off = in_len;
 861                } else if (is_dir_sep(in[j])) {
 862                        /* in="/a/b/c", prefix="/a/b" */
 863                        while (is_dir_sep(in[j]))
 864                                j++;
 865                        in_off = j;
 866                } else {
 867                        /* in="/a/bbb/c", prefix="/a/b" */
 868                        i = prefix_off;
 869                }
 870        } else if (
 871                   /* "in" is short than "prefix" */
 872                   j >= in_len &&
 873                   /* "in" not end with '/' */
 874                   in_off < in_len) {
 875                if (is_dir_sep(prefix[i])) {
 876                        /* in="/a/b", prefix="/a/b/c/" */
 877                        while (is_dir_sep(prefix[i]))
 878                                i++;
 879                        in_off = in_len;
 880                }
 881        }
 882        in += in_off;
 883        in_len -= in_off;
 884
 885        if (i >= prefix_len) {
 886                if (!in_len)
 887                        return "./";
 888                else
 889                        return in;
 890        }
 891
 892        strbuf_reset(sb);
 893        strbuf_grow(sb, in_len);
 894
 895        while (i < prefix_len) {
 896                if (is_dir_sep(prefix[i])) {
 897                        strbuf_addstr(sb, "../");
 898                        while (is_dir_sep(prefix[i]))
 899                                i++;
 900                        continue;
 901                }
 902                i++;
 903        }
 904        if (!is_dir_sep(prefix[prefix_len - 1]))
 905                strbuf_addstr(sb, "../");
 906
 907        strbuf_addstr(sb, in);
 908
 909        return sb->buf;
 910}
 911
 912/*
 913 * A simpler implementation of relative_path
 914 *
 915 * Get relative path by removing "prefix" from "in". This function
 916 * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
 917 * to increase performance when traversing the path to work_tree.
 918 */
 919const char *remove_leading_path(const char *in, const char *prefix)
 920{
 921        static struct strbuf buf = STRBUF_INIT;
 922        int i = 0, j = 0;
 923
 924        if (!prefix || !prefix[0])
 925                return in;
 926        while (prefix[i]) {
 927                if (is_dir_sep(prefix[i])) {
 928                        if (!is_dir_sep(in[j]))
 929                                return in;
 930                        while (is_dir_sep(prefix[i]))
 931                                i++;
 932                        while (is_dir_sep(in[j]))
 933                                j++;
 934                        continue;
 935                } else if (in[j] != prefix[i]) {
 936                        return in;
 937                }
 938                i++;
 939                j++;
 940        }
 941        if (
 942            /* "/foo" is a prefix of "/foo" */
 943            in[j] &&
 944            /* "/foo" is not a prefix of "/foobar" */
 945            !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
 946           )
 947                return in;
 948        while (is_dir_sep(in[j]))
 949                j++;
 950
 951        strbuf_reset(&buf);
 952        if (!in[j])
 953                strbuf_addstr(&buf, ".");
 954        else
 955                strbuf_addstr(&buf, in + j);
 956        return buf.buf;
 957}
 958
 959/*
 960 * It is okay if dst == src, but they should not overlap otherwise.
 961 *
 962 * Performs the following normalizations on src, storing the result in dst:
 963 * - Ensures that components are separated by '/' (Windows only)
 964 * - Squashes sequences of '/'.
 965 * - Removes "." components.
 966 * - Removes ".." components, and the components the precede them.
 967 * Returns failure (non-zero) if a ".." component appears as first path
 968 * component anytime during the normalization. Otherwise, returns success (0).
 969 *
 970 * Note that this function is purely textual.  It does not follow symlinks,
 971 * verify the existence of the path, or make any system calls.
 972 *
 973 * prefix_len != NULL is for a specific case of prefix_pathspec():
 974 * assume that src == dst and src[0..prefix_len-1] is already
 975 * normalized, any time "../" eats up to the prefix_len part,
 976 * prefix_len is reduced. In the end prefix_len is the remaining
 977 * prefix that has not been overridden by user pathspec.
 978 *
 979 * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
 980 * For everything but the root folder itself, the normalized path should not
 981 * end with a '/', then the callers need to be fixed up accordingly.
 982 *
 983 */
 984int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
 985{
 986        char *dst0;
 987        int i;
 988
 989        for (i = has_dos_drive_prefix(src); i > 0; i--)
 990                *dst++ = *src++;
 991        dst0 = dst;
 992
 993        if (is_dir_sep(*src)) {
 994                *dst++ = '/';
 995                while (is_dir_sep(*src))
 996                        src++;
 997        }
 998
 999        for (;;) {
1000                char c = *src;
1001
1002                /*
1003                 * A path component that begins with . could be
1004                 * special:
1005                 * (1) "." and ends   -- ignore and terminate.
1006                 * (2) "./"           -- ignore them, eat slash and continue.
1007                 * (3) ".." and ends  -- strip one and terminate.
1008                 * (4) "../"          -- strip one, eat slash and continue.
1009                 */
1010                if (c == '.') {
1011                        if (!src[1]) {
1012                                /* (1) */
1013                                src++;
1014                        } else if (is_dir_sep(src[1])) {
1015                                /* (2) */
1016                                src += 2;
1017                                while (is_dir_sep(*src))
1018                                        src++;
1019                                continue;
1020                        } else if (src[1] == '.') {
1021                                if (!src[2]) {
1022                                        /* (3) */
1023                                        src += 2;
1024                                        goto up_one;
1025                                } else if (is_dir_sep(src[2])) {
1026                                        /* (4) */
1027                                        src += 3;
1028                                        while (is_dir_sep(*src))
1029                                                src++;
1030                                        goto up_one;
1031                                }
1032                        }
1033                }
1034
1035                /* copy up to the next '/', and eat all '/' */
1036                while ((c = *src++) != '\0' && !is_dir_sep(c))
1037                        *dst++ = c;
1038                if (is_dir_sep(c)) {
1039                        *dst++ = '/';
1040                        while (is_dir_sep(c))
1041                                c = *src++;
1042                        src--;
1043                } else if (!c)
1044                        break;
1045                continue;
1046
1047        up_one:
1048                /*
1049                 * dst0..dst is prefix portion, and dst[-1] is '/';
1050                 * go up one level.
1051                 */
1052                dst--;  /* go to trailing '/' */
1053                if (dst <= dst0)
1054                        return -1;
1055                /* Windows: dst[-1] cannot be backslash anymore */
1056                while (dst0 < dst && dst[-1] != '/')
1057                        dst--;
1058                if (prefix_len && *prefix_len > dst - dst0)
1059                        *prefix_len = dst - dst0;
1060        }
1061        *dst = '\0';
1062        return 0;
1063}
1064
1065int normalize_path_copy(char *dst, const char *src)
1066{
1067        return normalize_path_copy_len(dst, src, NULL);
1068}
1069
1070/*
1071 * path = Canonical absolute path
1072 * prefixes = string_list containing normalized, absolute paths without
1073 * trailing slashes (except for the root directory, which is denoted by "/").
1074 *
1075 * Determines, for each path in prefixes, whether the "prefix"
1076 * is an ancestor directory of path.  Returns the length of the longest
1077 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1078 * is an ancestor.  (Note that this means 0 is returned if prefixes is
1079 * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1080 * are not considered to be their own ancestors.  path must be in a
1081 * canonical form: empty components, or "." or ".." components are not
1082 * allowed.
1083 */
1084int longest_ancestor_length(const char *path, struct string_list *prefixes)
1085{
1086        int i, max_len = -1;
1087
1088        if (!strcmp(path, "/"))
1089                return -1;
1090
1091        for (i = 0; i < prefixes->nr; i++) {
1092                const char *ceil = prefixes->items[i].string;
1093                int len = strlen(ceil);
1094
1095                if (len == 1 && ceil[0] == '/')
1096                        len = 0; /* root matches anything, with length 0 */
1097                else if (!strncmp(path, ceil, len) && path[len] == '/')
1098                        ; /* match of length len */
1099                else
1100                        continue; /* no match */
1101
1102                if (len > max_len)
1103                        max_len = len;
1104        }
1105
1106        return max_len;
1107}
1108
1109/* strip arbitrary amount of directory separators at end of path */
1110static inline int chomp_trailing_dir_sep(const char *path, int len)
1111{
1112        while (len && is_dir_sep(path[len - 1]))
1113                len--;
1114        return len;
1115}
1116
1117/*
1118 * If path ends with suffix (complete path components), returns the
1119 * part before suffix (sans trailing directory separators).
1120 * Otherwise returns NULL.
1121 */
1122char *strip_path_suffix(const char *path, const char *suffix)
1123{
1124        int path_len = strlen(path), suffix_len = strlen(suffix);
1125
1126        while (suffix_len) {
1127                if (!path_len)
1128                        return NULL;
1129
1130                if (is_dir_sep(path[path_len - 1])) {
1131                        if (!is_dir_sep(suffix[suffix_len - 1]))
1132                                return NULL;
1133                        path_len = chomp_trailing_dir_sep(path, path_len);
1134                        suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
1135                }
1136                else if (path[--path_len] != suffix[--suffix_len])
1137                        return NULL;
1138        }
1139
1140        if (path_len && !is_dir_sep(path[path_len - 1]))
1141                return NULL;
1142        return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
1143}
1144
1145int daemon_avoid_alias(const char *p)
1146{
1147        int sl, ndot;
1148
1149        /*
1150         * This resurrects the belts and suspenders paranoia check by HPA
1151         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
1152         * does not do getcwd() based path canonicalization.
1153         *
1154         * sl becomes true immediately after seeing '/' and continues to
1155         * be true as long as dots continue after that without intervening
1156         * non-dot character.
1157         */
1158        if (!p || (*p != '/' && *p != '~'))
1159                return -1;
1160        sl = 1; ndot = 0;
1161        p++;
1162
1163        while (1) {
1164                char ch = *p++;
1165                if (sl) {
1166                        if (ch == '.')
1167                                ndot++;
1168                        else if (ch == '/') {
1169                                if (ndot < 3)
1170                                        /* reject //, /./ and /../ */
1171                                        return -1;
1172                                ndot = 0;
1173                        }
1174                        else if (ch == 0) {
1175                                if (0 < ndot && ndot < 3)
1176                                        /* reject /.$ and /..$ */
1177                                        return -1;
1178                                return 0;
1179                        }
1180                        else
1181                                sl = ndot = 0;
1182                }
1183                else if (ch == 0)
1184                        return 0;
1185                else if (ch == '/') {
1186                        sl = 1;
1187                        ndot = 0;
1188                }
1189        }
1190}
1191
1192static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
1193{
1194        if (len < skip)
1195                return 0;
1196        len -= skip;
1197        path += skip;
1198        while (len-- > 0) {
1199                char c = *(path++);
1200                if (c != ' ' && c != '.')
1201                        return 0;
1202        }
1203        return 1;
1204}
1205
1206int is_ntfs_dotgit(const char *name)
1207{
1208        int len;
1209
1210        for (len = 0; ; len++)
1211                if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
1212                        if (only_spaces_and_periods(name, len, 4) &&
1213                                        !strncasecmp(name, ".git", 4))
1214                                return 1;
1215                        if (only_spaces_and_periods(name, len, 5) &&
1216                                        !strncasecmp(name, "git~1", 5))
1217                                return 1;
1218                        if (name[len] != '\\')
1219                                return 0;
1220                        name += len + 1;
1221                        len = -1;
1222                }
1223}
1224
1225char *xdg_config_home(const char *filename)
1226{
1227        const char *home, *config_home;
1228
1229        assert(filename);
1230        config_home = getenv("XDG_CONFIG_HOME");
1231        if (config_home && *config_home)
1232                return mkpathdup("%s/git/%s", config_home, filename);
1233
1234        home = getenv("HOME");
1235        if (home)
1236                return mkpathdup("%s/.config/git/%s", home, filename);
1237        return NULL;
1238}
1239
1240GIT_PATH_FUNC(git_path_cherry_pick_head, "CHERRY_PICK_HEAD")
1241GIT_PATH_FUNC(git_path_revert_head, "REVERT_HEAD")
1242GIT_PATH_FUNC(git_path_squash_msg, "SQUASH_MSG")
1243GIT_PATH_FUNC(git_path_merge_msg, "MERGE_MSG")
1244GIT_PATH_FUNC(git_path_merge_rr, "MERGE_RR")
1245GIT_PATH_FUNC(git_path_merge_mode, "MERGE_MODE")
1246GIT_PATH_FUNC(git_path_merge_head, "MERGE_HEAD")
1247GIT_PATH_FUNC(git_path_fetch_head, "FETCH_HEAD")
1248GIT_PATH_FUNC(git_path_shallow, "shallow")