path.con commit contrib/subtree: Make testing easier (43cce5c)
   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
   9static int get_st_mode_bits(const char *path, int *mode)
  10{
  11        struct stat st;
  12        if (lstat(path, &st) < 0)
  13                return -1;
  14        *mode = st.st_mode;
  15        return 0;
  16}
  17
  18static char bad_path[] = "/bad-path/";
  19
  20static struct strbuf *get_pathname(void)
  21{
  22        static struct strbuf pathname_array[4] = {
  23                STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
  24        };
  25        static int index;
  26        struct strbuf *sb = &pathname_array[3 & ++index];
  27        strbuf_reset(sb);
  28        return sb;
  29}
  30
  31static char *cleanup_path(char *path)
  32{
  33        /* Clean it up */
  34        if (!memcmp(path, "./", 2)) {
  35                path += 2;
  36                while (*path == '/')
  37                        path++;
  38        }
  39        return path;
  40}
  41
  42static void strbuf_cleanup_path(struct strbuf *sb)
  43{
  44        char *path = cleanup_path(sb->buf);
  45        if (path > sb->buf)
  46                strbuf_remove(sb, 0, path - sb->buf);
  47}
  48
  49char *mksnpath(char *buf, size_t n, const char *fmt, ...)
  50{
  51        va_list args;
  52        unsigned len;
  53
  54        va_start(args, fmt);
  55        len = vsnprintf(buf, n, fmt, args);
  56        va_end(args);
  57        if (len >= n) {
  58                strlcpy(buf, bad_path, n);
  59                return buf;
  60        }
  61        return cleanup_path(buf);
  62}
  63
  64static int dir_prefix(const char *buf, const char *dir)
  65{
  66        int len = strlen(dir);
  67        return !strncmp(buf, dir, len) &&
  68                (is_dir_sep(buf[len]) || buf[len] == '\0');
  69}
  70
  71/* $buf =~ m|$dir/+$file| but without regex */
  72static int is_dir_file(const char *buf, const char *dir, const char *file)
  73{
  74        int len = strlen(dir);
  75        if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
  76                return 0;
  77        while (is_dir_sep(buf[len]))
  78                len++;
  79        return !strcmp(buf + len, file);
  80}
  81
  82static void replace_dir(struct strbuf *buf, int len, const char *newdir)
  83{
  84        int newlen = strlen(newdir);
  85        int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
  86                !is_dir_sep(newdir[newlen - 1]);
  87        if (need_sep)
  88                len--;   /* keep one char, to be replaced with '/'  */
  89        strbuf_splice(buf, 0, len, newdir, newlen);
  90        if (need_sep)
  91                buf->buf[newlen] = '/';
  92}
  93
  94struct common_dir {
  95        /* Not considered garbage for report_linked_checkout_garbage */
  96        unsigned ignore_garbage:1;
  97        unsigned is_dir:1;
  98        /* Not common even though its parent is */
  99        unsigned exclude:1;
 100        const char *dirname;
 101};
 102
 103static struct common_dir common_list[] = {
 104        { 0, 1, 0, "branches" },
 105        { 0, 1, 0, "hooks" },
 106        { 0, 1, 0, "info" },
 107        { 0, 0, 1, "info/sparse-checkout" },
 108        { 1, 1, 0, "logs" },
 109        { 1, 1, 1, "logs/HEAD" },
 110        { 0, 1, 1, "logs/refs/bisect" },
 111        { 0, 1, 0, "lost-found" },
 112        { 0, 1, 0, "objects" },
 113        { 0, 1, 0, "refs" },
 114        { 0, 1, 1, "refs/bisect" },
 115        { 0, 1, 0, "remotes" },
 116        { 0, 1, 0, "worktrees" },
 117        { 0, 1, 0, "rr-cache" },
 118        { 0, 1, 0, "svn" },
 119        { 0, 0, 0, "config" },
 120        { 1, 0, 0, "gc.pid" },
 121        { 0, 0, 0, "packed-refs" },
 122        { 0, 0, 0, "shallow" },
 123        { 0, 0, 0, NULL }
 124};
 125
 126/*
 127 * A compressed trie.  A trie node consists of zero or more characters that
 128 * are common to all elements with this prefix, optionally followed by some
 129 * children.  If value is not NULL, the trie node is a terminal node.
 130 *
 131 * For example, consider the following set of strings:
 132 * abc
 133 * def
 134 * definite
 135 * definition
 136 *
 137 * The trie would look look like:
 138 * root: len = 0, children a and d non-NULL, value = NULL.
 139 *    a: len = 2, contents = bc, value = (data for "abc")
 140 *    d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
 141 *       i: len = 3, contents = nit, children e and i non-NULL, value = NULL
 142 *           e: len = 0, children all NULL, value = (data for "definite")
 143 *           i: len = 2, contents = on, children all NULL,
 144 *              value = (data for "definition")
 145 */
 146struct trie {
 147        struct trie *children[256];
 148        int len;
 149        char *contents;
 150        void *value;
 151};
 152
 153static struct trie *make_trie_node(const char *key, void *value)
 154{
 155        struct trie *new_node = xcalloc(1, sizeof(*new_node));
 156        new_node->len = strlen(key);
 157        if (new_node->len) {
 158                new_node->contents = xmalloc(new_node->len);
 159                memcpy(new_node->contents, key, new_node->len);
 160        }
 161        new_node->value = value;
 162        return new_node;
 163}
 164
 165/*
 166 * Add a key/value pair to a trie.  The key is assumed to be \0-terminated.
 167 * If there was an existing value for this key, return it.
 168 */
 169static void *add_to_trie(struct trie *root, const char *key, void *value)
 170{
 171        struct trie *child;
 172        void *old;
 173        int i;
 174
 175        if (!*key) {
 176                /* we have reached the end of the key */
 177                old = root->value;
 178                root->value = value;
 179                return old;
 180        }
 181
 182        for (i = 0; i < root->len; i++) {
 183                if (root->contents[i] == key[i])
 184                        continue;
 185
 186                /*
 187                 * Split this node: child will contain this node's
 188                 * existing children.
 189                 */
 190                child = malloc(sizeof(*child));
 191                memcpy(child->children, root->children, sizeof(root->children));
 192
 193                child->len = root->len - i - 1;
 194                if (child->len) {
 195                        child->contents = xstrndup(root->contents + i + 1,
 196                                                   child->len);
 197                }
 198                child->value = root->value;
 199                root->value = NULL;
 200                root->len = i;
 201
 202                memset(root->children, 0, sizeof(root->children));
 203                root->children[(unsigned char)root->contents[i]] = child;
 204
 205                /* This is the newly-added child. */
 206                root->children[(unsigned char)key[i]] =
 207                        make_trie_node(key + i + 1, value);
 208                return NULL;
 209        }
 210
 211        /* We have matched the entire compressed section */
 212        if (key[i]) {
 213                child = root->children[(unsigned char)key[root->len]];
 214                if (child) {
 215                        return add_to_trie(child, key + root->len + 1, value);
 216                } else {
 217                        child = make_trie_node(key + root->len + 1, value);
 218                        root->children[(unsigned char)key[root->len]] = child;
 219                        return NULL;
 220                }
 221        }
 222
 223        old = root->value;
 224        root->value = value;
 225        return old;
 226}
 227
 228typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
 229
 230/*
 231 * Search a trie for some key.  Find the longest /-or-\0-terminated
 232 * prefix of the key for which the trie contains a value.  Call fn
 233 * with the unmatched portion of the key and the found value, and
 234 * return its return value.  If there is no such prefix, return -1.
 235 *
 236 * The key is partially normalized: consecutive slashes are skipped.
 237 *
 238 * For example, consider the trie containing only [refs,
 239 * refs/worktree] (both with values).
 240 *
 241 * | key             | unmatched  | val from node | return value |
 242 * |-----------------|------------|---------------|--------------|
 243 * | a               | not called | n/a           | -1           |
 244 * | refs            | \0         | refs          | as per fn    |
 245 * | refs/           | /          | refs          | as per fn    |
 246 * | refs/w          | /w         | refs          | as per fn    |
 247 * | refs/worktree   | \0         | refs/worktree | as per fn    |
 248 * | refs/worktree/  | /          | refs/worktree | as per fn    |
 249 * | refs/worktree/a | /a         | refs/worktree | as per fn    |
 250 * |-----------------|------------|---------------|--------------|
 251 *
 252 */
 253static int trie_find(struct trie *root, const char *key, match_fn fn,
 254                     void *baton)
 255{
 256        int i;
 257        int result;
 258        struct trie *child;
 259
 260        if (!*key) {
 261                /* we have reached the end of the key */
 262                if (root->value && !root->len)
 263                        return fn(key, root->value, baton);
 264                else
 265                        return -1;
 266        }
 267
 268        for (i = 0; i < root->len; i++) {
 269                /* Partial path normalization: skip consecutive slashes. */
 270                if (key[i] == '/' && key[i+1] == '/') {
 271                        key++;
 272                        continue;
 273                }
 274                if (root->contents[i] != key[i])
 275                        return -1;
 276        }
 277
 278        /* Matched the entire compressed section */
 279        key += i;
 280        if (!*key)
 281                /* End of key */
 282                return fn(key, root->value, baton);
 283
 284        /* Partial path normalization: skip consecutive slashes */
 285        while (key[0] == '/' && key[1] == '/')
 286                key++;
 287
 288        child = root->children[(unsigned char)*key];
 289        if (child)
 290                result = trie_find(child, key + 1, fn, baton);
 291        else
 292                result = -1;
 293
 294        if (result >= 0 || (*key != '/' && *key != 0))
 295                return result;
 296        if (root->value)
 297                return fn(key, root->value, baton);
 298        else
 299                return -1;
 300}
 301
 302static struct trie common_trie;
 303static int common_trie_done_setup;
 304
 305static void init_common_trie(void)
 306{
 307        struct common_dir *p;
 308
 309        if (common_trie_done_setup)
 310                return;
 311
 312        for (p = common_list; p->dirname; p++)
 313                add_to_trie(&common_trie, p->dirname, p);
 314
 315        common_trie_done_setup = 1;
 316}
 317
 318/*
 319 * Helper function for update_common_dir: returns 1 if the dir
 320 * prefix is common.
 321 */
 322static int check_common(const char *unmatched, void *value, void *baton)
 323{
 324        struct common_dir *dir = value;
 325
 326        if (!dir)
 327                return 0;
 328
 329        if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
 330                return !dir->exclude;
 331
 332        if (!dir->is_dir && unmatched[0] == 0)
 333                return !dir->exclude;
 334
 335        return 0;
 336}
 337
 338static void update_common_dir(struct strbuf *buf, int git_dir_len,
 339                              const char *common_dir)
 340{
 341        char *base = buf->buf + git_dir_len;
 342        init_common_trie();
 343        if (!common_dir)
 344                common_dir = get_git_common_dir();
 345        if (trie_find(&common_trie, base, check_common, NULL) > 0)
 346                replace_dir(buf, git_dir_len, common_dir);
 347}
 348
 349void report_linked_checkout_garbage(void)
 350{
 351        struct strbuf sb = STRBUF_INIT;
 352        const struct common_dir *p;
 353        int len;
 354
 355        if (!git_common_dir_env)
 356                return;
 357        strbuf_addf(&sb, "%s/", get_git_dir());
 358        len = sb.len;
 359        for (p = common_list; p->dirname; p++) {
 360                const char *path = p->dirname;
 361                if (p->ignore_garbage)
 362                        continue;
 363                strbuf_setlen(&sb, len);
 364                strbuf_addstr(&sb, path);
 365                if (file_exists(sb.buf))
 366                        report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
 367        }
 368        strbuf_release(&sb);
 369}
 370
 371static void adjust_git_path(struct strbuf *buf, int git_dir_len)
 372{
 373        const char *base = buf->buf + git_dir_len;
 374        if (git_graft_env && is_dir_file(base, "info", "grafts"))
 375                strbuf_splice(buf, 0, buf->len,
 376                              get_graft_file(), strlen(get_graft_file()));
 377        else if (git_index_env && !strcmp(base, "index"))
 378                strbuf_splice(buf, 0, buf->len,
 379                              get_index_file(), strlen(get_index_file()));
 380        else if (git_db_env && dir_prefix(base, "objects"))
 381                replace_dir(buf, git_dir_len + 7, get_object_directory());
 382        else if (git_common_dir_env)
 383                update_common_dir(buf, git_dir_len, NULL);
 384}
 385
 386static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
 387{
 388        int gitdir_len;
 389        strbuf_addstr(buf, get_git_dir());
 390        if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
 391                strbuf_addch(buf, '/');
 392        gitdir_len = buf->len;
 393        strbuf_vaddf(buf, fmt, args);
 394        adjust_git_path(buf, gitdir_len);
 395        strbuf_cleanup_path(buf);
 396}
 397
 398char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
 399{
 400        va_list args;
 401        strbuf_reset(buf);
 402        va_start(args, fmt);
 403        do_git_path(buf, fmt, args);
 404        va_end(args);
 405        return buf->buf;
 406}
 407
 408void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 409{
 410        va_list args;
 411        va_start(args, fmt);
 412        do_git_path(sb, fmt, args);
 413        va_end(args);
 414}
 415
 416const char *git_path(const char *fmt, ...)
 417{
 418        struct strbuf *pathname = get_pathname();
 419        va_list args;
 420        va_start(args, fmt);
 421        do_git_path(pathname, fmt, args);
 422        va_end(args);
 423        return pathname->buf;
 424}
 425
 426char *git_pathdup(const char *fmt, ...)
 427{
 428        struct strbuf path = STRBUF_INIT;
 429        va_list args;
 430        va_start(args, fmt);
 431        do_git_path(&path, fmt, args);
 432        va_end(args);
 433        return strbuf_detach(&path, NULL);
 434}
 435
 436char *mkpathdup(const char *fmt, ...)
 437{
 438        struct strbuf sb = STRBUF_INIT;
 439        va_list args;
 440        va_start(args, fmt);
 441        strbuf_vaddf(&sb, fmt, args);
 442        va_end(args);
 443        strbuf_cleanup_path(&sb);
 444        return strbuf_detach(&sb, NULL);
 445}
 446
 447const char *mkpath(const char *fmt, ...)
 448{
 449        va_list args;
 450        struct strbuf *pathname = get_pathname();
 451        va_start(args, fmt);
 452        strbuf_vaddf(pathname, fmt, args);
 453        va_end(args);
 454        return cleanup_path(pathname->buf);
 455}
 456
 457static void do_submodule_path(struct strbuf *buf, const char *path,
 458                              const char *fmt, va_list args)
 459{
 460        const char *git_dir;
 461        struct strbuf git_submodule_common_dir = STRBUF_INIT;
 462        struct strbuf git_submodule_dir = STRBUF_INIT;
 463
 464        strbuf_addstr(buf, path);
 465        strbuf_complete(buf, '/');
 466        strbuf_addstr(buf, ".git");
 467
 468        git_dir = read_gitfile(buf->buf);
 469        if (git_dir) {
 470                strbuf_reset(buf);
 471                strbuf_addstr(buf, git_dir);
 472        }
 473        strbuf_addch(buf, '/');
 474        strbuf_addstr(&git_submodule_dir, buf->buf);
 475
 476        strbuf_vaddf(buf, fmt, args);
 477
 478        if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
 479                update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
 480
 481        strbuf_cleanup_path(buf);
 482
 483        strbuf_release(&git_submodule_dir);
 484        strbuf_release(&git_submodule_common_dir);
 485}
 486
 487char *git_pathdup_submodule(const char *path, const char *fmt, ...)
 488{
 489        va_list args;
 490        struct strbuf buf = STRBUF_INIT;
 491        va_start(args, fmt);
 492        do_submodule_path(&buf, path, fmt, args);
 493        va_end(args);
 494        return strbuf_detach(&buf, NULL);
 495}
 496
 497void strbuf_git_path_submodule(struct strbuf *buf, const char *path,
 498                               const char *fmt, ...)
 499{
 500        va_list args;
 501        va_start(args, fmt);
 502        do_submodule_path(buf, path, fmt, args);
 503        va_end(args);
 504}
 505
 506int validate_headref(const char *path)
 507{
 508        struct stat st;
 509        char *buf, buffer[256];
 510        unsigned char sha1[20];
 511        int fd;
 512        ssize_t len;
 513
 514        if (lstat(path, &st) < 0)
 515                return -1;
 516
 517        /* Make sure it is a "refs/.." symlink */
 518        if (S_ISLNK(st.st_mode)) {
 519                len = readlink(path, buffer, sizeof(buffer)-1);
 520                if (len >= 5 && !memcmp("refs/", buffer, 5))
 521                        return 0;
 522                return -1;
 523        }
 524
 525        /*
 526         * Anything else, just open it and try to see if it is a symbolic ref.
 527         */
 528        fd = open(path, O_RDONLY);
 529        if (fd < 0)
 530                return -1;
 531        len = read_in_full(fd, buffer, sizeof(buffer)-1);
 532        close(fd);
 533
 534        /*
 535         * Is it a symbolic ref?
 536         */
 537        if (len < 4)
 538                return -1;
 539        if (!memcmp("ref:", buffer, 4)) {
 540                buf = buffer + 4;
 541                len -= 4;
 542                while (len && isspace(*buf))
 543                        buf++, len--;
 544                if (len >= 5 && !memcmp("refs/", buf, 5))
 545                        return 0;
 546        }
 547
 548        /*
 549         * Is this a detached HEAD?
 550         */
 551        if (!get_sha1_hex(buffer, sha1))
 552                return 0;
 553
 554        return -1;
 555}
 556
 557static struct passwd *getpw_str(const char *username, size_t len)
 558{
 559        struct passwd *pw;
 560        char *username_z = xmemdupz(username, len);
 561        pw = getpwnam(username_z);
 562        free(username_z);
 563        return pw;
 564}
 565
 566/*
 567 * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
 568 * then it is a newly allocated string. Returns NULL on getpw failure or
 569 * if path is NULL.
 570 */
 571char *expand_user_path(const char *path)
 572{
 573        struct strbuf user_path = STRBUF_INIT;
 574        const char *to_copy = path;
 575
 576        if (path == NULL)
 577                goto return_null;
 578        if (path[0] == '~') {
 579                const char *first_slash = strchrnul(path, '/');
 580                const char *username = path + 1;
 581                size_t username_len = first_slash - username;
 582                if (username_len == 0) {
 583                        const char *home = getenv("HOME");
 584                        if (!home)
 585                                goto return_null;
 586                        strbuf_addstr(&user_path, home);
 587                } else {
 588                        struct passwd *pw = getpw_str(username, username_len);
 589                        if (!pw)
 590                                goto return_null;
 591                        strbuf_addstr(&user_path, pw->pw_dir);
 592                }
 593                to_copy = first_slash;
 594        }
 595        strbuf_addstr(&user_path, to_copy);
 596        return strbuf_detach(&user_path, NULL);
 597return_null:
 598        strbuf_release(&user_path);
 599        return NULL;
 600}
 601
 602/*
 603 * First, one directory to try is determined by the following algorithm.
 604 *
 605 * (0) If "strict" is given, the path is used as given and no DWIM is
 606 *     done. Otherwise:
 607 * (1) "~/path" to mean path under the running user's home directory;
 608 * (2) "~user/path" to mean path under named user's home directory;
 609 * (3) "relative/path" to mean cwd relative directory; or
 610 * (4) "/absolute/path" to mean absolute directory.
 611 *
 612 * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
 613 * in this order. We select the first one that is a valid git repository, and
 614 * chdir() to it. If none match, or we fail to chdir, we return NULL.
 615 *
 616 * If all goes well, we return the directory we used to chdir() (but
 617 * before ~user is expanded), avoiding getcwd() resolving symbolic
 618 * links.  User relative paths are also returned as they are given,
 619 * except DWIM suffixing.
 620 */
 621const char *enter_repo(const char *path, int strict)
 622{
 623        static struct strbuf validated_path = STRBUF_INIT;
 624        static struct strbuf used_path = STRBUF_INIT;
 625
 626        if (!path)
 627                return NULL;
 628
 629        if (!strict) {
 630                static const char *suffix[] = {
 631                        "/.git", "", ".git/.git", ".git", NULL,
 632                };
 633                const char *gitfile;
 634                int len = strlen(path);
 635                int i;
 636                while ((1 < len) && (path[len-1] == '/'))
 637                        len--;
 638
 639                /*
 640                 * We can handle arbitrary-sized buffers, but this remains as a
 641                 * sanity check on untrusted input.
 642                 */
 643                if (PATH_MAX <= len)
 644                        return NULL;
 645
 646                strbuf_reset(&used_path);
 647                strbuf_reset(&validated_path);
 648                strbuf_add(&used_path, path, len);
 649                strbuf_add(&validated_path, path, len);
 650
 651                if (used_path.buf[0] == '~') {
 652                        char *newpath = expand_user_path(used_path.buf);
 653                        if (!newpath)
 654                                return NULL;
 655                        strbuf_attach(&used_path, newpath, strlen(newpath),
 656                                      strlen(newpath));
 657                }
 658                for (i = 0; suffix[i]; i++) {
 659                        struct stat st;
 660                        size_t baselen = used_path.len;
 661                        strbuf_addstr(&used_path, suffix[i]);
 662                        if (!stat(used_path.buf, &st) &&
 663                            (S_ISREG(st.st_mode) ||
 664                            (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
 665                                strbuf_addstr(&validated_path, suffix[i]);
 666                                break;
 667                        }
 668                        strbuf_setlen(&used_path, baselen);
 669                }
 670                if (!suffix[i])
 671                        return NULL;
 672                gitfile = read_gitfile(used_path.buf);
 673                if (gitfile) {
 674                        strbuf_reset(&used_path);
 675                        strbuf_addstr(&used_path, gitfile);
 676                }
 677                if (chdir(used_path.buf))
 678                        return NULL;
 679                path = validated_path.buf;
 680        }
 681        else {
 682                const char *gitfile = read_gitfile(path);
 683                if (gitfile)
 684                        path = gitfile;
 685                if (chdir(path))
 686                        return NULL;
 687        }
 688
 689        if (is_git_directory(".")) {
 690                set_git_dir(".");
 691                check_repository_format();
 692                return path;
 693        }
 694
 695        return NULL;
 696}
 697
 698static int calc_shared_perm(int mode)
 699{
 700        int tweak;
 701
 702        if (shared_repository < 0)
 703                tweak = -shared_repository;
 704        else
 705                tweak = shared_repository;
 706
 707        if (!(mode & S_IWUSR))
 708                tweak &= ~0222;
 709        if (mode & S_IXUSR)
 710                /* Copy read bits to execute bits */
 711                tweak |= (tweak & 0444) >> 2;
 712        if (shared_repository < 0)
 713                mode = (mode & ~0777) | tweak;
 714        else
 715                mode |= tweak;
 716
 717        return mode;
 718}
 719
 720
 721int adjust_shared_perm(const char *path)
 722{
 723        int old_mode, new_mode;
 724
 725        if (!shared_repository)
 726                return 0;
 727        if (get_st_mode_bits(path, &old_mode) < 0)
 728                return -1;
 729
 730        new_mode = calc_shared_perm(old_mode);
 731        if (S_ISDIR(old_mode)) {
 732                /* Copy read bits to execute bits */
 733                new_mode |= (new_mode & 0444) >> 2;
 734                new_mode |= FORCE_DIR_SET_GID;
 735        }
 736
 737        if (((old_mode ^ new_mode) & ~S_IFMT) &&
 738                        chmod(path, (new_mode & ~S_IFMT)) < 0)
 739                return -2;
 740        return 0;
 741}
 742
 743void safe_create_dir(const char *dir, int share)
 744{
 745        if (mkdir(dir, 0777) < 0) {
 746                if (errno != EEXIST) {
 747                        perror(dir);
 748                        exit(1);
 749                }
 750        }
 751        else if (share && adjust_shared_perm(dir))
 752                die(_("Could not make %s writable by group"), dir);
 753}
 754
 755static int have_same_root(const char *path1, const char *path2)
 756{
 757        int is_abs1, is_abs2;
 758
 759        is_abs1 = is_absolute_path(path1);
 760        is_abs2 = is_absolute_path(path2);
 761        return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
 762               (!is_abs1 && !is_abs2);
 763}
 764
 765/*
 766 * Give path as relative to prefix.
 767 *
 768 * The strbuf may or may not be used, so do not assume it contains the
 769 * returned path.
 770 */
 771const char *relative_path(const char *in, const char *prefix,
 772                          struct strbuf *sb)
 773{
 774        int in_len = in ? strlen(in) : 0;
 775        int prefix_len = prefix ? strlen(prefix) : 0;
 776        int in_off = 0;
 777        int prefix_off = 0;
 778        int i = 0, j = 0;
 779
 780        if (!in_len)
 781                return "./";
 782        else if (!prefix_len)
 783                return in;
 784
 785        if (have_same_root(in, prefix)) {
 786                /* bypass dos_drive, for "c:" is identical to "C:" */
 787                if (has_dos_drive_prefix(in)) {
 788                        i = 2;
 789                        j = 2;
 790                }
 791        } else {
 792                return in;
 793        }
 794
 795        while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
 796                if (is_dir_sep(prefix[i])) {
 797                        while (is_dir_sep(prefix[i]))
 798                                i++;
 799                        while (is_dir_sep(in[j]))
 800                                j++;
 801                        prefix_off = i;
 802                        in_off = j;
 803                } else {
 804                        i++;
 805                        j++;
 806                }
 807        }
 808
 809        if (
 810            /* "prefix" seems like prefix of "in" */
 811            i >= prefix_len &&
 812            /*
 813             * but "/foo" is not a prefix of "/foobar"
 814             * (i.e. prefix not end with '/')
 815             */
 816            prefix_off < prefix_len) {
 817                if (j >= in_len) {
 818                        /* in="/a/b", prefix="/a/b" */
 819                        in_off = in_len;
 820                } else if (is_dir_sep(in[j])) {
 821                        /* in="/a/b/c", prefix="/a/b" */
 822                        while (is_dir_sep(in[j]))
 823                                j++;
 824                        in_off = j;
 825                } else {
 826                        /* in="/a/bbb/c", prefix="/a/b" */
 827                        i = prefix_off;
 828                }
 829        } else if (
 830                   /* "in" is short than "prefix" */
 831                   j >= in_len &&
 832                   /* "in" not end with '/' */
 833                   in_off < in_len) {
 834                if (is_dir_sep(prefix[i])) {
 835                        /* in="/a/b", prefix="/a/b/c/" */
 836                        while (is_dir_sep(prefix[i]))
 837                                i++;
 838                        in_off = in_len;
 839                }
 840        }
 841        in += in_off;
 842        in_len -= in_off;
 843
 844        if (i >= prefix_len) {
 845                if (!in_len)
 846                        return "./";
 847                else
 848                        return in;
 849        }
 850
 851        strbuf_reset(sb);
 852        strbuf_grow(sb, in_len);
 853
 854        while (i < prefix_len) {
 855                if (is_dir_sep(prefix[i])) {
 856                        strbuf_addstr(sb, "../");
 857                        while (is_dir_sep(prefix[i]))
 858                                i++;
 859                        continue;
 860                }
 861                i++;
 862        }
 863        if (!is_dir_sep(prefix[prefix_len - 1]))
 864                strbuf_addstr(sb, "../");
 865
 866        strbuf_addstr(sb, in);
 867
 868        return sb->buf;
 869}
 870
 871/*
 872 * A simpler implementation of relative_path
 873 *
 874 * Get relative path by removing "prefix" from "in". This function
 875 * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
 876 * to increase performance when traversing the path to work_tree.
 877 */
 878const char *remove_leading_path(const char *in, const char *prefix)
 879{
 880        static struct strbuf buf = STRBUF_INIT;
 881        int i = 0, j = 0;
 882
 883        if (!prefix || !prefix[0])
 884                return in;
 885        while (prefix[i]) {
 886                if (is_dir_sep(prefix[i])) {
 887                        if (!is_dir_sep(in[j]))
 888                                return in;
 889                        while (is_dir_sep(prefix[i]))
 890                                i++;
 891                        while (is_dir_sep(in[j]))
 892                                j++;
 893                        continue;
 894                } else if (in[j] != prefix[i]) {
 895                        return in;
 896                }
 897                i++;
 898                j++;
 899        }
 900        if (
 901            /* "/foo" is a prefix of "/foo" */
 902            in[j] &&
 903            /* "/foo" is not a prefix of "/foobar" */
 904            !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
 905           )
 906                return in;
 907        while (is_dir_sep(in[j]))
 908                j++;
 909
 910        strbuf_reset(&buf);
 911        if (!in[j])
 912                strbuf_addstr(&buf, ".");
 913        else
 914                strbuf_addstr(&buf, in + j);
 915        return buf.buf;
 916}
 917
 918/*
 919 * It is okay if dst == src, but they should not overlap otherwise.
 920 *
 921 * Performs the following normalizations on src, storing the result in dst:
 922 * - Ensures that components are separated by '/' (Windows only)
 923 * - Squashes sequences of '/'.
 924 * - Removes "." components.
 925 * - Removes ".." components, and the components the precede them.
 926 * Returns failure (non-zero) if a ".." component appears as first path
 927 * component anytime during the normalization. Otherwise, returns success (0).
 928 *
 929 * Note that this function is purely textual.  It does not follow symlinks,
 930 * verify the existence of the path, or make any system calls.
 931 *
 932 * prefix_len != NULL is for a specific case of prefix_pathspec():
 933 * assume that src == dst and src[0..prefix_len-1] is already
 934 * normalized, any time "../" eats up to the prefix_len part,
 935 * prefix_len is reduced. In the end prefix_len is the remaining
 936 * prefix that has not been overridden by user pathspec.
 937 *
 938 * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
 939 * For everything but the root folder itself, the normalized path should not
 940 * end with a '/', then the callers need to be fixed up accordingly.
 941 *
 942 */
 943int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
 944{
 945        char *dst0;
 946
 947        if (has_dos_drive_prefix(src)) {
 948                *dst++ = *src++;
 949                *dst++ = *src++;
 950        }
 951        dst0 = dst;
 952
 953        if (is_dir_sep(*src)) {
 954                *dst++ = '/';
 955                while (is_dir_sep(*src))
 956                        src++;
 957        }
 958
 959        for (;;) {
 960                char c = *src;
 961
 962                /*
 963                 * A path component that begins with . could be
 964                 * special:
 965                 * (1) "." and ends   -- ignore and terminate.
 966                 * (2) "./"           -- ignore them, eat slash and continue.
 967                 * (3) ".." and ends  -- strip one and terminate.
 968                 * (4) "../"          -- strip one, eat slash and continue.
 969                 */
 970                if (c == '.') {
 971                        if (!src[1]) {
 972                                /* (1) */
 973                                src++;
 974                        } else if (is_dir_sep(src[1])) {
 975                                /* (2) */
 976                                src += 2;
 977                                while (is_dir_sep(*src))
 978                                        src++;
 979                                continue;
 980                        } else if (src[1] == '.') {
 981                                if (!src[2]) {
 982                                        /* (3) */
 983                                        src += 2;
 984                                        goto up_one;
 985                                } else if (is_dir_sep(src[2])) {
 986                                        /* (4) */
 987                                        src += 3;
 988                                        while (is_dir_sep(*src))
 989                                                src++;
 990                                        goto up_one;
 991                                }
 992                        }
 993                }
 994
 995                /* copy up to the next '/', and eat all '/' */
 996                while ((c = *src++) != '\0' && !is_dir_sep(c))
 997                        *dst++ = c;
 998                if (is_dir_sep(c)) {
 999                        *dst++ = '/';
1000                        while (is_dir_sep(c))
1001                                c = *src++;
1002                        src--;
1003                } else if (!c)
1004                        break;
1005                continue;
1006
1007        up_one:
1008                /*
1009                 * dst0..dst is prefix portion, and dst[-1] is '/';
1010                 * go up one level.
1011                 */
1012                dst--;  /* go to trailing '/' */
1013                if (dst <= dst0)
1014                        return -1;
1015                /* Windows: dst[-1] cannot be backslash anymore */
1016                while (dst0 < dst && dst[-1] != '/')
1017                        dst--;
1018                if (prefix_len && *prefix_len > dst - dst0)
1019                        *prefix_len = dst - dst0;
1020        }
1021        *dst = '\0';
1022        return 0;
1023}
1024
1025int normalize_path_copy(char *dst, const char *src)
1026{
1027        return normalize_path_copy_len(dst, src, NULL);
1028}
1029
1030/*
1031 * path = Canonical absolute path
1032 * prefixes = string_list containing normalized, absolute paths without
1033 * trailing slashes (except for the root directory, which is denoted by "/").
1034 *
1035 * Determines, for each path in prefixes, whether the "prefix"
1036 * is an ancestor directory of path.  Returns the length of the longest
1037 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1038 * is an ancestor.  (Note that this means 0 is returned if prefixes is
1039 * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1040 * are not considered to be their own ancestors.  path must be in a
1041 * canonical form: empty components, or "." or ".." components are not
1042 * allowed.
1043 */
1044int longest_ancestor_length(const char *path, struct string_list *prefixes)
1045{
1046        int i, max_len = -1;
1047
1048        if (!strcmp(path, "/"))
1049                return -1;
1050
1051        for (i = 0; i < prefixes->nr; i++) {
1052                const char *ceil = prefixes->items[i].string;
1053                int len = strlen(ceil);
1054
1055                if (len == 1 && ceil[0] == '/')
1056                        len = 0; /* root matches anything, with length 0 */
1057                else if (!strncmp(path, ceil, len) && path[len] == '/')
1058                        ; /* match of length len */
1059                else
1060                        continue; /* no match */
1061
1062                if (len > max_len)
1063                        max_len = len;
1064        }
1065
1066        return max_len;
1067}
1068
1069/* strip arbitrary amount of directory separators at end of path */
1070static inline int chomp_trailing_dir_sep(const char *path, int len)
1071{
1072        while (len && is_dir_sep(path[len - 1]))
1073                len--;
1074        return len;
1075}
1076
1077/*
1078 * If path ends with suffix (complete path components), returns the
1079 * part before suffix (sans trailing directory separators).
1080 * Otherwise returns NULL.
1081 */
1082char *strip_path_suffix(const char *path, const char *suffix)
1083{
1084        int path_len = strlen(path), suffix_len = strlen(suffix);
1085
1086        while (suffix_len) {
1087                if (!path_len)
1088                        return NULL;
1089
1090                if (is_dir_sep(path[path_len - 1])) {
1091                        if (!is_dir_sep(suffix[suffix_len - 1]))
1092                                return NULL;
1093                        path_len = chomp_trailing_dir_sep(path, path_len);
1094                        suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
1095                }
1096                else if (path[--path_len] != suffix[--suffix_len])
1097                        return NULL;
1098        }
1099
1100        if (path_len && !is_dir_sep(path[path_len - 1]))
1101                return NULL;
1102        return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
1103}
1104
1105int daemon_avoid_alias(const char *p)
1106{
1107        int sl, ndot;
1108
1109        /*
1110         * This resurrects the belts and suspenders paranoia check by HPA
1111         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
1112         * does not do getcwd() based path canonicalization.
1113         *
1114         * sl becomes true immediately after seeing '/' and continues to
1115         * be true as long as dots continue after that without intervening
1116         * non-dot character.
1117         */
1118        if (!p || (*p != '/' && *p != '~'))
1119                return -1;
1120        sl = 1; ndot = 0;
1121        p++;
1122
1123        while (1) {
1124                char ch = *p++;
1125                if (sl) {
1126                        if (ch == '.')
1127                                ndot++;
1128                        else if (ch == '/') {
1129                                if (ndot < 3)
1130                                        /* reject //, /./ and /../ */
1131                                        return -1;
1132                                ndot = 0;
1133                        }
1134                        else if (ch == 0) {
1135                                if (0 < ndot && ndot < 3)
1136                                        /* reject /.$ and /..$ */
1137                                        return -1;
1138                                return 0;
1139                        }
1140                        else
1141                                sl = ndot = 0;
1142                }
1143                else if (ch == 0)
1144                        return 0;
1145                else if (ch == '/') {
1146                        sl = 1;
1147                        ndot = 0;
1148                }
1149        }
1150}
1151
1152static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
1153{
1154        if (len < skip)
1155                return 0;
1156        len -= skip;
1157        path += skip;
1158        while (len-- > 0) {
1159                char c = *(path++);
1160                if (c != ' ' && c != '.')
1161                        return 0;
1162        }
1163        return 1;
1164}
1165
1166int is_ntfs_dotgit(const char *name)
1167{
1168        int len;
1169
1170        for (len = 0; ; len++)
1171                if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
1172                        if (only_spaces_and_periods(name, len, 4) &&
1173                                        !strncasecmp(name, ".git", 4))
1174                                return 1;
1175                        if (only_spaces_and_periods(name, len, 5) &&
1176                                        !strncasecmp(name, "git~1", 5))
1177                                return 1;
1178                        if (name[len] != '\\')
1179                                return 0;
1180                        name += len + 1;
1181                        len = -1;
1182                }
1183}
1184
1185char *xdg_config_home(const char *filename)
1186{
1187        const char *home, *config_home;
1188
1189        assert(filename);
1190        config_home = getenv("XDG_CONFIG_HOME");
1191        if (config_home && *config_home)
1192                return mkpathdup("%s/git/%s", config_home, filename);
1193
1194        home = getenv("HOME");
1195        if (home)
1196                return mkpathdup("%s/.config/git/%s", home, filename);
1197        return NULL;
1198}
1199
1200GIT_PATH_FUNC(git_path_cherry_pick_head, "CHERRY_PICK_HEAD")
1201GIT_PATH_FUNC(git_path_revert_head, "REVERT_HEAD")
1202GIT_PATH_FUNC(git_path_squash_msg, "SQUASH_MSG")
1203GIT_PATH_FUNC(git_path_merge_msg, "MERGE_MSG")
1204GIT_PATH_FUNC(git_path_merge_rr, "MERGE_RR")
1205GIT_PATH_FUNC(git_path_merge_mode, "MERGE_MODE")
1206GIT_PATH_FUNC(git_path_merge_head, "MERGE_HEAD")
1207GIT_PATH_FUNC(git_path_fetch_head, "FETCH_HEAD")
1208GIT_PATH_FUNC(git_path_shallow, "shallow")