git

1
/*
2
 * Utilities for paths and pathnames
3
 */
4

5
#include "git-compat-util.h"
6
#include "abspath.h"
7
#include "environment.h"
8
#include "gettext.h"
9
#include "repository.h"
10
#include "strbuf.h"
11
#include "string-list.h"
12
#include "dir.h"
13
#include "worktree.h"
14
#include "setup.h"
15
#include "submodule-config.h"
16
#include "path.h"
17
#include "packfile.h"
18
#include "object-store-ll.h"
19
#include "lockfile.h"
20
#include "exec-cmd.h"
21

22
static int get_st_mode_bits(const char *path, int *mode)
23
{
24
	struct stat st;
25
	if (lstat(path, &st) < 0)
26
		return -1;
27
	*mode = st.st_mode;
28
	return 0;
29
}
30

31
struct strbuf *get_pathname(void)
32
{
33
	static struct strbuf pathname_array[4] = {
34
		STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
35
	};
36
	static int index;
37
	struct strbuf *sb = &pathname_array[index];
38
	index = (index + 1) % ARRAY_SIZE(pathname_array);
39
	strbuf_reset(sb);
40
	return sb;
41
}
42

43
static const char *cleanup_path(const char *path)
44
{
45
	/* Clean it up */
46
	if (skip_prefix(path, "./", &path)) {
47
		while (*path == '/')
48
			path++;
49
	}
50
	return path;
51
}
52

53
static void strbuf_cleanup_path(struct strbuf *sb)
54
{
55
	const char *path = cleanup_path(sb->buf);
56
	if (path > sb->buf)
57
		strbuf_remove(sb, 0, path - sb->buf);
58
}
59

60
static int dir_prefix(const char *buf, const char *dir)
61
{
62
	int len = strlen(dir);
63
	return !strncmp(buf, dir, len) &&
64
		(is_dir_sep(buf[len]) || buf[len] == '\0');
65
}
66

67
/* $buf =~ m|$dir/+$file| but without regex */
68
static int is_dir_file(const char *buf, const char *dir, const char *file)
69
{
70
	int len = strlen(dir);
71
	if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
72
		return 0;
73
	while (is_dir_sep(buf[len]))
74
		len++;
75
	return !strcmp(buf + len, file);
76
}
77

78
static void replace_dir(struct strbuf *buf, int len, const char *newdir)
79
{
80
	int newlen = strlen(newdir);
81
	int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
82
		!is_dir_sep(newdir[newlen - 1]);
83
	if (need_sep)
84
		len--;	 /* keep one char, to be replaced with '/'  */
85
	strbuf_splice(buf, 0, len, newdir, newlen);
86
	if (need_sep)
87
		buf->buf[newlen] = '/';
88
}
89

90
struct common_dir {
91
	/* Not considered garbage for report_linked_checkout_garbage */
92
	unsigned ignore_garbage:1;
93
	unsigned is_dir:1;
94
	/* Belongs to the common dir, though it may contain paths that don't */
95
	unsigned is_common:1;
96
	const char *path;
97
};
98

99
static struct common_dir common_list[] = {
100
	{ 0, 1, 1, "branches" },
101
	{ 0, 1, 1, "common" },
102
	{ 0, 1, 1, "hooks" },
103
	{ 0, 1, 1, "info" },
104
	{ 0, 0, 0, "info/sparse-checkout" },
105
	{ 1, 1, 1, "logs" },
106
	{ 1, 0, 0, "logs/HEAD" },
107
	{ 0, 1, 0, "logs/refs/bisect" },
108
	{ 0, 1, 0, "logs/refs/rewritten" },
109
	{ 0, 1, 0, "logs/refs/worktree" },
110
	{ 0, 1, 1, "lost-found" },
111
	{ 0, 1, 1, "objects" },
112
	{ 0, 1, 1, "refs" },
113
	{ 0, 1, 0, "refs/bisect" },
114
	{ 0, 1, 0, "refs/rewritten" },
115
	{ 0, 1, 0, "refs/worktree" },
116
	{ 0, 1, 1, "remotes" },
117
	{ 0, 1, 1, "worktrees" },
118
	{ 0, 1, 1, "rr-cache" },
119
	{ 0, 1, 1, "svn" },
120
	{ 0, 0, 1, "config" },
121
	{ 1, 0, 1, "gc.pid" },
122
	{ 0, 0, 1, "packed-refs" },
123
	{ 0, 0, 1, "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
 */
147
struct trie {
148
	struct trie *children[256];
149
	int len;
150
	char *contents;
151
	void *value;
152
};
153

154
static 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
 */
170
static 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 = xmalloc(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

229
typedef int (*match_fn)(const char *unmatched, void *value, 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.  If there is
234
 * no such prefix, return -1.  Otherwise call fn with the unmatched
235
 * portion of the key and the found value.  If fn returns 0 or
236
 * positive, then return its return value.  If fn returns negative,
237
 * then call fn with the next-longest /-terminated prefix of the key
238
 * (i.e. a parent directory) for which the trie contains a value, and
239
 * handle its return value the same way.  If there is no shorter
240
 * /-terminated prefix with a value left, then return the negative
241
 * return value of the most recent fn invocation.
242
 *
243
 * The key is partially normalized: consecutive slashes are skipped.
244
 *
245
 * For example, consider the trie containing only [logs,
246
 * logs/refs/bisect], both with values, but not logs/refs.
247
 *
248
 * | key                | unmatched      | prefix to node   | return value |
249
 * |--------------------|----------------|------------------|--------------|
250
 * | a                  | not called     | n/a              | -1           |
251
 * | logstore           | not called     | n/a              | -1           |
252
 * | logs               | \0             | logs             | as per fn    |
253
 * | logs/              | /              | logs             | as per fn    |
254
 * | logs/refs          | /refs          | logs             | as per fn    |
255
 * | logs/refs/         | /refs/         | logs             | as per fn    |
256
 * | logs/refs/b        | /refs/b        | logs             | as per fn    |
257
 * | logs/refs/bisected | /refs/bisected | logs             | as per fn    |
258
 * | logs/refs/bisect   | \0             | logs/refs/bisect | as per fn    |
259
 * | logs/refs/bisect/  | /              | logs/refs/bisect | as per fn    |
260
 * | logs/refs/bisect/a | /a             | logs/refs/bisect | as per fn    |
261
 * | (If fn in the previous line returns -1, then fn is called once more:) |
262
 * | logs/refs/bisect/a | /refs/bisect/a | logs             | as per fn    |
263
 * |--------------------|----------------|------------------|--------------|
264
 */
265
static int trie_find(struct trie *root, const char *key, match_fn fn,
266
		     void *baton)
267
{
268
	int i;
269
	int result;
270
	struct trie *child;
271

272
	if (!*key) {
273
		/* we have reached the end of the key */
274
		if (root->value && !root->len)
275
			return fn(key, root->value, baton);
276
		else
277
			return -1;
278
	}
279

280
	for (i = 0; i < root->len; i++) {
281
		/* Partial path normalization: skip consecutive slashes. */
282
		if (key[i] == '/' && key[i+1] == '/') {
283
			key++;
284
			continue;
285
		}
286
		if (root->contents[i] != key[i])
287
			return -1;
288
	}
289

290
	/* Matched the entire compressed section */
291
	key += i;
292
	if (!*key) {
293
		/* End of key */
294
		if (root->value)
295
			return fn(key, root->value, baton);
296
		else
297
			return -1;
298
	}
299

300
	/* Partial path normalization: skip consecutive slashes */
301
	while (key[0] == '/' && key[1] == '/')
302
		key++;
303

304
	child = root->children[(unsigned char)*key];
305
	if (child)
306
		result = trie_find(child, key + 1, fn, baton);
307
	else
308
		result = -1;
309

310
	if (result >= 0 || (*key != '/' && *key != 0))
311
		return result;
312
	if (root->value)
313
		return fn(key, root->value, baton);
314
	else
315
		return -1;
316
}
317

318
static struct trie common_trie;
319
static int common_trie_done_setup;
320

321
static void init_common_trie(void)
322
{
323
	struct common_dir *p;
324

325
	if (common_trie_done_setup)
326
		return;
327

328
	for (p = common_list; p->path; p++)
329
		add_to_trie(&common_trie, p->path, p);
330

331
	common_trie_done_setup = 1;
332
}
333

334
/*
335
 * Helper function for update_common_dir: returns 1 if the dir
336
 * prefix is common.
337
 */
338
static int check_common(const char *unmatched, void *value,
339
			void *baton UNUSED)
340
{
341
	struct common_dir *dir = value;
342

343
	if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
344
		return dir->is_common;
345

346
	if (!dir->is_dir && unmatched[0] == 0)
347
		return dir->is_common;
348

349
	return 0;
350
}
351

352
static void update_common_dir(struct strbuf *buf, int git_dir_len,
353
			      const char *common_dir)
354
{
355
	char *base = buf->buf + git_dir_len;
356
	int has_lock_suffix = strbuf_strip_suffix(buf, LOCK_SUFFIX);
357

358
	init_common_trie();
359
	if (trie_find(&common_trie, base, check_common, NULL) > 0)
360
		replace_dir(buf, git_dir_len, common_dir);
361

362
	if (has_lock_suffix)
363
		strbuf_addstr(buf, LOCK_SUFFIX);
364
}
365

366
void report_linked_checkout_garbage(struct repository *r)
367
{
368
	struct strbuf sb = STRBUF_INIT;
369
	const struct common_dir *p;
370
	int len;
371

372
	if (!r->different_commondir)
373
		return;
374
	strbuf_addf(&sb, "%s/", r->gitdir);
375
	len = sb.len;
376
	for (p = common_list; p->path; p++) {
377
		const char *path = p->path;
378
		if (p->ignore_garbage)
379
			continue;
380
		strbuf_setlen(&sb, len);
381
		strbuf_addstr(&sb, path);
382
		if (file_exists(sb.buf))
383
			report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
384
	}
385
	strbuf_release(&sb);
386
}
387

388
static void adjust_git_path(const struct repository *repo,
389
			    struct strbuf *buf, int git_dir_len)
390
{
391
	const char *base = buf->buf + git_dir_len;
392
	if (is_dir_file(base, "info", "grafts"))
393
		strbuf_splice(buf, 0, buf->len,
394
			      repo->graft_file, strlen(repo->graft_file));
395
	else if (!strcmp(base, "index"))
396
		strbuf_splice(buf, 0, buf->len,
397
			      repo->index_file, strlen(repo->index_file));
398
	else if (dir_prefix(base, "objects"))
399
		replace_dir(buf, git_dir_len + 7, repo->objects->odb->path);
400
	else if (git_hooks_path && dir_prefix(base, "hooks"))
401
		replace_dir(buf, git_dir_len + 5, git_hooks_path);
402
	else if (repo->different_commondir)
403
		update_common_dir(buf, git_dir_len, repo->commondir);
404
}
405

406
static void strbuf_worktree_gitdir(struct strbuf *buf,
407
				   const struct repository *repo,
408
				   const struct worktree *wt)
409
{
410
	if (!wt)
411
		strbuf_addstr(buf, repo->gitdir);
412
	else if (!wt->id)
413
		strbuf_addstr(buf, repo->commondir);
414
	else
415
		strbuf_git_common_path(buf, repo, "worktrees/%s", wt->id);
416
}
417

418
void repo_git_pathv(const struct repository *repo,
419
		    const struct worktree *wt, struct strbuf *buf,
420
		    const char *fmt, va_list args)
421
{
422
	int gitdir_len;
423
	strbuf_worktree_gitdir(buf, repo, wt);
424
	if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
425
		strbuf_addch(buf, '/');
426
	gitdir_len = buf->len;
427
	strbuf_vaddf(buf, fmt, args);
428
	if (!wt)
429
		adjust_git_path(repo, buf, gitdir_len);
430
	strbuf_cleanup_path(buf);
431
}
432

433
char *repo_git_path(const struct repository *repo,
434
		    const char *fmt, ...)
435
{
436
	struct strbuf path = STRBUF_INIT;
437
	va_list args;
438
	va_start(args, fmt);
439
	repo_git_pathv(repo, NULL, &path, fmt, args);
440
	va_end(args);
441
	return strbuf_detach(&path, NULL);
442
}
443

444
void strbuf_repo_git_path(struct strbuf *sb,
445
			  const struct repository *repo,
446
			  const char *fmt, ...)
447
{
448
	va_list args;
449
	va_start(args, fmt);
450
	repo_git_pathv(repo, NULL, sb, fmt, args);
451
	va_end(args);
452
}
453

454
char *mkpathdup(const char *fmt, ...)
455
{
456
	struct strbuf sb = STRBUF_INIT;
457
	va_list args;
458
	va_start(args, fmt);
459
	strbuf_vaddf(&sb, fmt, args);
460
	va_end(args);
461
	strbuf_cleanup_path(&sb);
462
	return strbuf_detach(&sb, NULL);
463
}
464

465
const char *mkpath(const char *fmt, ...)
466
{
467
	va_list args;
468
	struct strbuf *pathname = get_pathname();
469
	va_start(args, fmt);
470
	strbuf_vaddf(pathname, fmt, args);
471
	va_end(args);
472
	return cleanup_path(pathname->buf);
473
}
474

475
const char *worktree_git_path(struct repository *r,
476
			      const struct worktree *wt, const char *fmt, ...)
477
{
478
	struct strbuf *pathname = get_pathname();
479
	va_list args;
480

481
	if (wt && wt->repo != r)
482
		BUG("worktree not connected to expected repository");
483

484
	va_start(args, fmt);
485
	repo_git_pathv(r, wt, pathname, fmt, args);
486
	va_end(args);
487
	return pathname->buf;
488
}
489

490
static void do_worktree_path(const struct repository *repo,
491
			     struct strbuf *buf,
492
			     const char *fmt, va_list args)
493
{
494
	strbuf_addstr(buf, repo->worktree);
495
	if(buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
496
		strbuf_addch(buf, '/');
497

498
	strbuf_vaddf(buf, fmt, args);
499
	strbuf_cleanup_path(buf);
500
}
501

502
char *repo_worktree_path(const struct repository *repo, const char *fmt, ...)
503
{
504
	struct strbuf path = STRBUF_INIT;
505
	va_list args;
506

507
	if (!repo->worktree)
508
		return NULL;
509

510
	va_start(args, fmt);
511
	do_worktree_path(repo, &path, fmt, args);
512
	va_end(args);
513

514
	return strbuf_detach(&path, NULL);
515
}
516

517
void strbuf_repo_worktree_path(struct strbuf *sb,
518
			       const struct repository *repo,
519
			       const char *fmt, ...)
520
{
521
	va_list args;
522

523
	if (!repo->worktree)
524
		return;
525

526
	va_start(args, fmt);
527
	do_worktree_path(repo, sb, fmt, args);
528
	va_end(args);
529
}
530

531
/* Returns 0 on success, negative on failure. */
532
static int do_submodule_path(struct strbuf *buf, const char *path,
533
			     const char *fmt, va_list args)
534
{
535
	struct strbuf git_submodule_common_dir = STRBUF_INIT;
536
	struct strbuf git_submodule_dir = STRBUF_INIT;
537
	int ret;
538

539
	ret = submodule_to_gitdir(&git_submodule_dir, path);
540
	if (ret)
541
		goto cleanup;
542

543
	strbuf_complete(&git_submodule_dir, '/');
544
	strbuf_addbuf(buf, &git_submodule_dir);
545
	strbuf_vaddf(buf, fmt, args);
546

547
	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
548
		update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
549

550
	strbuf_cleanup_path(buf);
551

552
cleanup:
553
	strbuf_release(&git_submodule_dir);
554
	strbuf_release(&git_submodule_common_dir);
555
	return ret;
556
}
557

558
char *git_pathdup_submodule(const char *path, const char *fmt, ...)
559
{
560
	int err;
561
	va_list args;
562
	struct strbuf buf = STRBUF_INIT;
563
	va_start(args, fmt);
564
	err = do_submodule_path(&buf, path, fmt, args);
565
	va_end(args);
566
	if (err) {
567
		strbuf_release(&buf);
568
		return NULL;
569
	}
570
	return strbuf_detach(&buf, NULL);
571
}
572

573
int strbuf_git_path_submodule(struct strbuf *buf, const char *path,
574
			      const char *fmt, ...)
575
{
576
	int err;
577
	va_list args;
578
	va_start(args, fmt);
579
	err = do_submodule_path(buf, path, fmt, args);
580
	va_end(args);
581

582
	return err;
583
}
584

585
void repo_common_pathv(const struct repository *repo,
586
		       struct strbuf *sb,
587
		       const char *fmt,
588
		       va_list args)
589
{
590
	strbuf_addstr(sb, repo->commondir);
591
	if (sb->len && !is_dir_sep(sb->buf[sb->len - 1]))
592
		strbuf_addch(sb, '/');
593
	strbuf_vaddf(sb, fmt, args);
594
	strbuf_cleanup_path(sb);
595
}
596

597
void strbuf_git_common_path(struct strbuf *sb,
598
			    const struct repository *repo,
599
			    const char *fmt, ...)
600
{
601
	va_list args;
602
	va_start(args, fmt);
603
	repo_common_pathv(repo, sb, fmt, args);
604
	va_end(args);
605
}
606

607
static struct passwd *getpw_str(const char *username, size_t len)
608
{
609
	struct passwd *pw;
610
	char *username_z = xmemdupz(username, len);
611
	pw = getpwnam(username_z);
612
	free(username_z);
613
	return pw;
614
}
615

616
/*
617
 * Return a string with ~ and ~user expanded via getpw*. Returns NULL on getpw
618
 * failure or if path is NULL.
619
 *
620
 * If real_home is true, strbuf_realpath($HOME) is used in the `~/` expansion.
621
 *
622
 * If the path starts with `%(prefix)/`, the remainder is interpreted as
623
 * relative to where Git is installed, and expanded to the absolute path.
624
 */
625
char *interpolate_path(const char *path, int real_home)
626
{
627
	struct strbuf user_path = STRBUF_INIT;
628
	const char *to_copy = path;
629

630
	if (!path)
631
		goto return_null;
632

633
	if (skip_prefix(path, "%(prefix)/", &path))
634
		return system_path(path);
635

636
	if (path[0] == '~') {
637
		const char *first_slash = strchrnul(path, '/');
638
		const char *username = path + 1;
639
		size_t username_len = first_slash - username;
640
		if (username_len == 0) {
641
			const char *home = getenv("HOME");
642
			if (!home)
643
				goto return_null;
644
			if (real_home)
645
				strbuf_add_real_path(&user_path, home);
646
			else
647
				strbuf_addstr(&user_path, home);
648
#ifdef GIT_WINDOWS_NATIVE
649
			convert_slashes(user_path.buf);
650
#endif
651
		} else {
652
			struct passwd *pw = getpw_str(username, username_len);
653
			if (!pw)
654
				goto return_null;
655
			strbuf_addstr(&user_path, pw->pw_dir);
656
		}
657
		to_copy = first_slash;
658
	}
659
	strbuf_addstr(&user_path, to_copy);
660
	return strbuf_detach(&user_path, NULL);
661
return_null:
662
	strbuf_release(&user_path);
663
	return NULL;
664
}
665

666
/*
667
 * First, one directory to try is determined by the following algorithm.
668
 *
669
 * (0) If "strict" is given, the path is used as given and no DWIM is
670
 *     done. Otherwise:
671
 * (1) "~/path" to mean path under the running user's home directory;
672
 * (2) "~user/path" to mean path under named user's home directory;
673
 * (3) "relative/path" to mean cwd relative directory; or
674
 * (4) "/absolute/path" to mean absolute directory.
675
 *
676
 * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
677
 * in this order. We select the first one that is a valid git repository, and
678
 * chdir() to it. If none match, or we fail to chdir, we return NULL.
679
 *
680
 * If all goes well, we return the directory we used to chdir() (but
681
 * before ~user is expanded), avoiding getcwd() resolving symbolic
682
 * links.  User relative paths are also returned as they are given,
683
 * except DWIM suffixing.
684
 */
685
const char *enter_repo(const char *path, int strict)
686
{
687
	static struct strbuf validated_path = STRBUF_INIT;
688
	static struct strbuf used_path = STRBUF_INIT;
689

690
	if (!path)
691
		return NULL;
692

693
	if (!strict) {
694
		static const char *suffix[] = {
695
			"/.git", "", ".git/.git", ".git", NULL,
696
		};
697
		const char *gitfile;
698
		int len = strlen(path);
699
		int i;
700
		while ((1 < len) && (path[len-1] == '/'))
701
			len--;
702

703
		/*
704
		 * We can handle arbitrary-sized buffers, but this remains as a
705
		 * sanity check on untrusted input.
706
		 */
707
		if (PATH_MAX <= len)
708
			return NULL;
709

710
		strbuf_reset(&used_path);
711
		strbuf_reset(&validated_path);
712
		strbuf_add(&used_path, path, len);
713
		strbuf_add(&validated_path, path, len);
714

715
		if (used_path.buf[0] == '~') {
716
			char *newpath = interpolate_path(used_path.buf, 0);
717
			if (!newpath)
718
				return NULL;
719
			strbuf_attach(&used_path, newpath, strlen(newpath),
720
				      strlen(newpath));
721
		}
722
		for (i = 0; suffix[i]; i++) {
723
			struct stat st;
724
			size_t baselen = used_path.len;
725
			strbuf_addstr(&used_path, suffix[i]);
726
			if (!stat(used_path.buf, &st) &&
727
			    (S_ISREG(st.st_mode) ||
728
			    (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
729
				strbuf_addstr(&validated_path, suffix[i]);
730
				break;
731
			}
732
			strbuf_setlen(&used_path, baselen);
733
		}
734
		if (!suffix[i])
735
			return NULL;
736
		gitfile = read_gitfile(used_path.buf);
737
		die_upon_dubious_ownership(gitfile, NULL, used_path.buf);
738
		if (gitfile) {
739
			strbuf_reset(&used_path);
740
			strbuf_addstr(&used_path, gitfile);
741
		}
742
		if (chdir(used_path.buf))
743
			return NULL;
744
		path = validated_path.buf;
745
	}
746
	else {
747
		const char *gitfile = read_gitfile(path);
748
		die_upon_dubious_ownership(gitfile, NULL, path);
749
		if (gitfile)
750
			path = gitfile;
751
		if (chdir(path))
752
			return NULL;
753
	}
754

755
	if (is_git_directory(".")) {
756
		set_git_dir(".", 0);
757
		check_repository_format(NULL);
758
		return path;
759
	}
760

761
	return NULL;
762
}
763

764
int calc_shared_perm(int mode)
765
{
766
	int tweak;
767

768
	if (get_shared_repository() < 0)
769
		tweak = -get_shared_repository();
770
	else
771
		tweak = get_shared_repository();
772

773
	if (!(mode & S_IWUSR))
774
		tweak &= ~0222;
775
	if (mode & S_IXUSR)
776
		/* Copy read bits to execute bits */
777
		tweak |= (tweak & 0444) >> 2;
778
	if (get_shared_repository() < 0)
779
		mode = (mode & ~0777) | tweak;
780
	else
781
		mode |= tweak;
782

783
	return mode;
784
}
785

786

787
int adjust_shared_perm(const char *path)
788
{
789
	int old_mode, new_mode;
790

791
	if (!get_shared_repository())
792
		return 0;
793
	if (get_st_mode_bits(path, &old_mode) < 0)
794
		return -1;
795

796
	new_mode = calc_shared_perm(old_mode);
797
	if (S_ISDIR(old_mode)) {
798
		/* Copy read bits to execute bits */
799
		new_mode |= (new_mode & 0444) >> 2;
800

801
		/*
802
		 * g+s matters only if any extra access is granted
803
		 * based on group membership.
804
		 */
805
		if (FORCE_DIR_SET_GID && (new_mode & 060))
806
			new_mode |= FORCE_DIR_SET_GID;
807
	}
808

809
	if (((old_mode ^ new_mode) & ~S_IFMT) &&
810
			chmod(path, (new_mode & ~S_IFMT)) < 0)
811
		return -2;
812
	return 0;
813
}
814

815
void safe_create_dir(const char *dir, int share)
816
{
817
	if (mkdir(dir, 0777) < 0) {
818
		if (errno != EEXIST) {
819
			perror(dir);
820
			exit(1);
821
		}
822
	}
823
	else if (share && adjust_shared_perm(dir))
824
		die(_("Could not make %s writable by group"), dir);
825
}
826

827
static int have_same_root(const char *path1, const char *path2)
828
{
829
	int is_abs1, is_abs2;
830

831
	is_abs1 = is_absolute_path(path1);
832
	is_abs2 = is_absolute_path(path2);
833
	return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
834
	       (!is_abs1 && !is_abs2);
835
}
836

837
/*
838
 * Give path as relative to prefix.
839
 *
840
 * The strbuf may or may not be used, so do not assume it contains the
841
 * returned path.
842
 */
843
const char *relative_path(const char *in, const char *prefix,
844
			  struct strbuf *sb)
845
{
846
	int in_len = in ? strlen(in) : 0;
847
	int prefix_len = prefix ? strlen(prefix) : 0;
848
	int in_off = 0;
849
	int prefix_off = 0;
850
	int i = 0, j = 0;
851

852
	if (!in_len)
853
		return "./";
854
	else if (!prefix_len)
855
		return in;
856

857
	if (have_same_root(in, prefix))
858
		/* bypass dos_drive, for "c:" is identical to "C:" */
859
		i = j = has_dos_drive_prefix(in);
860
	else {
861
		return in;
862
	}
863

864
	while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
865
		if (is_dir_sep(prefix[i])) {
866
			while (is_dir_sep(prefix[i]))
867
				i++;
868
			while (is_dir_sep(in[j]))
869
				j++;
870
			prefix_off = i;
871
			in_off = j;
872
		} else {
873
			i++;
874
			j++;
875
		}
876
	}
877

878
	if (
879
	    /* "prefix" seems like prefix of "in" */
880
	    i >= prefix_len &&
881
	    /*
882
	     * but "/foo" is not a prefix of "/foobar"
883
	     * (i.e. prefix not end with '/')
884
	     */
885
	    prefix_off < prefix_len) {
886
		if (j >= in_len) {
887
			/* in="/a/b", prefix="/a/b" */
888
			in_off = in_len;
889
		} else if (is_dir_sep(in[j])) {
890
			/* in="/a/b/c", prefix="/a/b" */
891
			while (is_dir_sep(in[j]))
892
				j++;
893
			in_off = j;
894
		} else {
895
			/* in="/a/bbb/c", prefix="/a/b" */
896
			i = prefix_off;
897
		}
898
	} else if (
899
		   /* "in" is short than "prefix" */
900
		   j >= in_len &&
901
		   /* "in" not end with '/' */
902
		   in_off < in_len) {
903
		if (is_dir_sep(prefix[i])) {
904
			/* in="/a/b", prefix="/a/b/c/" */
905
			while (is_dir_sep(prefix[i]))
906
				i++;
907
			in_off = in_len;
908
		}
909
	}
910
	in += in_off;
911
	in_len -= in_off;
912

913
	if (i >= prefix_len) {
914
		if (!in_len)
915
			return "./";
916
		else
917
			return in;
918
	}
919

920
	strbuf_reset(sb);
921
	strbuf_grow(sb, in_len);
922

923
	while (i < prefix_len) {
924
		if (is_dir_sep(prefix[i])) {
925
			strbuf_addstr(sb, "../");
926
			while (is_dir_sep(prefix[i]))
927
				i++;
928
			continue;
929
		}
930
		i++;
931
	}
932
	if (!is_dir_sep(prefix[prefix_len - 1]))
933
		strbuf_addstr(sb, "../");
934

935
	strbuf_addstr(sb, in);
936

937
	return sb->buf;
938
}
939

940
/*
941
 * A simpler implementation of relative_path
942
 *
943
 * Get relative path by removing "prefix" from "in". This function
944
 * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
945
 * to increase performance when traversing the path to work_tree.
946
 */
947
const char *remove_leading_path(const char *in, const char *prefix)
948
{
949
	static struct strbuf buf = STRBUF_INIT;
950
	int i = 0, j = 0;
951

952
	if (!prefix || !prefix[0])
953
		return in;
954
	while (prefix[i]) {
955
		if (is_dir_sep(prefix[i])) {
956
			if (!is_dir_sep(in[j]))
957
				return in;
958
			while (is_dir_sep(prefix[i]))
959
				i++;
960
			while (is_dir_sep(in[j]))
961
				j++;
962
			continue;
963
		} else if (in[j] != prefix[i]) {
964
			return in;
965
		}
966
		i++;
967
		j++;
968
	}
969
	if (
970
	    /* "/foo" is a prefix of "/foo" */
971
	    in[j] &&
972
	    /* "/foo" is not a prefix of "/foobar" */
973
	    !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
974
	   )
975
		return in;
976
	while (is_dir_sep(in[j]))
977
		j++;
978

979
	strbuf_reset(&buf);
980
	if (!in[j])
981
		strbuf_addstr(&buf, ".");
982
	else
983
		strbuf_addstr(&buf, in + j);
984
	return buf.buf;
985
}
986

987
/*
988
 * It is okay if dst == src, but they should not overlap otherwise.
989
 * The "dst" buffer must be at least as long as "src"; normalizing may shrink
990
 * the size of the path, but will never grow it.
991
 *
992
 * Performs the following normalizations on src, storing the result in dst:
993
 * - Ensures that components are separated by '/' (Windows only)
994
 * - Squashes sequences of '/' except "//server/share" on Windows
995
 * - Removes "." components.
996
 * - Removes ".." components, and the components the precede them.
997
 * Returns failure (non-zero) if a ".." component appears as first path
998
 * component anytime during the normalization. Otherwise, returns success (0).
999
 *
1000
 * Note that this function is purely textual.  It does not follow symlinks,
1001
 * verify the existence of the path, or make any system calls.
1002
 *
1003
 * prefix_len != NULL is for a specific case of prefix_pathspec():
1004
 * assume that src == dst and src[0..prefix_len-1] is already
1005
 * normalized, any time "../" eats up to the prefix_len part,
1006
 * prefix_len is reduced. In the end prefix_len is the remaining
1007
 * prefix that has not been overridden by user pathspec.
1008
 *
1009
 * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
1010
 * For everything but the root folder itself, the normalized path should not
1011
 * end with a '/', then the callers need to be fixed up accordingly.
1012
 *
1013
 */
1014
int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
1015
{
1016
	char *dst0;
1017
	const char *end;
1018

1019
	/*
1020
	 * Copy initial part of absolute path: "/", "C:/", "//server/share/".
1021
	 */
1022
	end = src + offset_1st_component(src);
1023
	while (src < end) {
1024
		char c = *src++;
1025
		if (is_dir_sep(c))
1026
			c = '/';
1027
		*dst++ = c;
1028
	}
1029
	dst0 = dst;
1030

1031
	while (is_dir_sep(*src))
1032
		src++;
1033

1034
	for (;;) {
1035
		char c = *src;
1036

1037
		/*
1038
		 * A path component that begins with . could be
1039
		 * special:
1040
		 * (1) "." and ends   -- ignore and terminate.
1041
		 * (2) "./"           -- ignore them, eat slash and continue.
1042
		 * (3) ".." and ends  -- strip one and terminate.
1043
		 * (4) "../"          -- strip one, eat slash and continue.
1044
		 */
1045
		if (c == '.') {
1046
			if (!src[1]) {
1047
				/* (1) */
1048
				src++;
1049
			} else if (is_dir_sep(src[1])) {
1050
				/* (2) */
1051
				src += 2;
1052
				while (is_dir_sep(*src))
1053
					src++;
1054
				continue;
1055
			} else if (src[1] == '.') {
1056
				if (!src[2]) {
1057
					/* (3) */
1058
					src += 2;
1059
					goto up_one;
1060
				} else if (is_dir_sep(src[2])) {
1061
					/* (4) */
1062
					src += 3;
1063
					while (is_dir_sep(*src))
1064
						src++;
1065
					goto up_one;
1066
				}
1067
			}
1068
		}
1069

1070
		/* copy up to the next '/', and eat all '/' */
1071
		while ((c = *src++) != '\0' && !is_dir_sep(c))
1072
			*dst++ = c;
1073
		if (is_dir_sep(c)) {
1074
			*dst++ = '/';
1075
			while (is_dir_sep(c))
1076
				c = *src++;
1077
			src--;
1078
		} else if (!c)
1079
			break;
1080
		continue;
1081

1082
	up_one:
1083
		/*
1084
		 * dst0..dst is prefix portion, and dst[-1] is '/';
1085
		 * go up one level.
1086
		 */
1087
		dst--;	/* go to trailing '/' */
1088
		if (dst <= dst0)
1089
			return -1;
1090
		/* Windows: dst[-1] cannot be backslash anymore */
1091
		while (dst0 < dst && dst[-1] != '/')
1092
			dst--;
1093
		if (prefix_len && *prefix_len > dst - dst0)
1094
			*prefix_len = dst - dst0;
1095
	}
1096
	*dst = '\0';
1097
	return 0;
1098
}
1099

1100
int normalize_path_copy(char *dst, const char *src)
1101
{
1102
	return normalize_path_copy_len(dst, src, NULL);
1103
}
1104

1105
int strbuf_normalize_path(struct strbuf *src)
1106
{
1107
	struct strbuf dst = STRBUF_INIT;
1108

1109
	strbuf_grow(&dst, src->len);
1110
	if (normalize_path_copy(dst.buf, src->buf) < 0) {
1111
		strbuf_release(&dst);
1112
		return -1;
1113
	}
1114

1115
	/*
1116
	 * normalize_path does not tell us the new length, so we have to
1117
	 * compute it by looking for the new NUL it placed
1118
	 */
1119
	strbuf_setlen(&dst, strlen(dst.buf));
1120
	strbuf_swap(src, &dst);
1121
	strbuf_release(&dst);
1122
	return 0;
1123
}
1124

1125
/*
1126
 * path = Canonical absolute path
1127
 * prefixes = string_list containing normalized, absolute paths without
1128
 * trailing slashes (except for the root directory, which is denoted by "/").
1129
 *
1130
 * Determines, for each path in prefixes, whether the "prefix"
1131
 * is an ancestor directory of path.  Returns the length of the longest
1132
 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1133
 * is an ancestor.  (Note that this means 0 is returned if prefixes is
1134
 * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1135
 * are not considered to be their own ancestors.  path must be in a
1136
 * canonical form: empty components, or "." or ".." components are not
1137
 * allowed.
1138
 */
1139
int longest_ancestor_length(const char *path, struct string_list *prefixes)
1140
{
1141
	int i, max_len = -1;
1142

1143
	if (!strcmp(path, "/"))
1144
		return -1;
1145

1146
	for (i = 0; i < prefixes->nr; i++) {
1147
		const char *ceil = prefixes->items[i].string;
1148
		int len = strlen(ceil);
1149

1150
		/*
1151
		 * For root directories (`/`, `C:/`, `//server/share/`)
1152
		 * adjust the length to exclude the trailing slash.
1153
		 */
1154
		if (len > 0 && ceil[len - 1] == '/')
1155
			len--;
1156

1157
		if (strncmp(path, ceil, len) ||
1158
		    path[len] != '/' || !path[len + 1])
1159
			continue; /* no match */
1160

1161
		if (len > max_len)
1162
			max_len = len;
1163
	}
1164

1165
	return max_len;
1166
}
1167

1168
/* strip arbitrary amount of directory separators at end of path */
1169
static inline int chomp_trailing_dir_sep(const char *path, int len)
1170
{
1171
	while (len && is_dir_sep(path[len - 1]))
1172
		len--;
1173
	return len;
1174
}
1175

1176
/*
1177
 * If path ends with suffix (complete path components), returns the offset of
1178
 * the last character in the path before the suffix (sans trailing directory
1179
 * separators), and -1 otherwise.
1180
 */
1181
static ssize_t stripped_path_suffix_offset(const char *path, const char *suffix)
1182
{
1183
	int path_len = strlen(path), suffix_len = strlen(suffix);
1184

1185
	while (suffix_len) {
1186
		if (!path_len)
1187
			return -1;
1188

1189
		if (is_dir_sep(path[path_len - 1])) {
1190
			if (!is_dir_sep(suffix[suffix_len - 1]))
1191
				return -1;
1192
			path_len = chomp_trailing_dir_sep(path, path_len);
1193
			suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
1194
		}
1195
		else if (path[--path_len] != suffix[--suffix_len])
1196
			return -1;
1197
	}
1198

1199
	if (path_len && !is_dir_sep(path[path_len - 1]))
1200
		return -1;
1201
	return chomp_trailing_dir_sep(path, path_len);
1202
}
1203

1204
/*
1205
 * Returns true if the path ends with components, considering only complete path
1206
 * components, and false otherwise.
1207
 */
1208
int ends_with_path_components(const char *path, const char *components)
1209
{
1210
	return stripped_path_suffix_offset(path, components) != -1;
1211
}
1212

1213
/*
1214
 * If path ends with suffix (complete path components), returns the
1215
 * part before suffix (sans trailing directory separators).
1216
 * Otherwise returns NULL.
1217
 */
1218
char *strip_path_suffix(const char *path, const char *suffix)
1219
{
1220
	ssize_t offset = stripped_path_suffix_offset(path, suffix);
1221

1222
	return offset == -1 ? NULL : xstrndup(path, offset);
1223
}
1224

1225
int daemon_avoid_alias(const char *p)
1226
{
1227
	int sl, ndot;
1228

1229
	/*
1230
	 * This resurrects the belts and suspenders paranoia check by HPA
1231
	 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
1232
	 * does not do getcwd() based path canonicalization.
1233
	 *
1234
	 * sl becomes true immediately after seeing '/' and continues to
1235
	 * be true as long as dots continue after that without intervening
1236
	 * non-dot character.
1237
	 */
1238
	if (!p || (*p != '/' && *p != '~'))
1239
		return -1;
1240
	sl = 1; ndot = 0;
1241
	p++;
1242

1243
	while (1) {
1244
		char ch = *p++;
1245
		if (sl) {
1246
			if (ch == '.')
1247
				ndot++;
1248
			else if (ch == '/') {
1249
				if (ndot < 3)
1250
					/* reject //, /./ and /../ */
1251
					return -1;
1252
				ndot = 0;
1253
			}
1254
			else if (ch == 0) {
1255
				if (0 < ndot && ndot < 3)
1256
					/* reject /.$ and /..$ */
1257
					return -1;
1258
				return 0;
1259
			}
1260
			else
1261
				sl = ndot = 0;
1262
		}
1263
		else if (ch == 0)
1264
			return 0;
1265
		else if (ch == '/') {
1266
			sl = 1;
1267
			ndot = 0;
1268
		}
1269
	}
1270
}
1271

1272
/*
1273
 * On NTFS, we need to be careful to disallow certain synonyms of the `.git/`
1274
 * directory:
1275
 *
1276
 * - For historical reasons, file names that end in spaces or periods are
1277
 *   automatically trimmed. Therefore, `.git . . ./` is a valid way to refer
1278
 *   to `.git/`.
1279
 *
1280
 * - For other historical reasons, file names that do not conform to the 8.3
1281
 *   format (up to eight characters for the basename, three for the file
1282
 *   extension, certain characters not allowed such as `+`, etc) are associated
1283
 *   with a so-called "short name", at least on the `C:` drive by default.
1284
 *   Which means that `git~1/` is a valid way to refer to `.git/`.
1285
 *
1286
 *   Note: Technically, `.git/` could receive the short name `git~2` if the
1287
 *   short name `git~1` were already used. In Git, however, we guarantee that
1288
 *   `.git` is the first item in a directory, therefore it will be associated
1289
 *   with the short name `git~1` (unless short names are disabled).
1290
 *
1291
 * - For yet other historical reasons, NTFS supports so-called "Alternate Data
1292
 *   Streams", i.e. metadata associated with a given file, referred to via
1293
 *   `<filename>:<stream-name>:<stream-type>`. There exists a default stream
1294
 *   type for directories, allowing `.git/` to be accessed via
1295
 *   `.git::$INDEX_ALLOCATION/`.
1296
 *
1297
 * When this function returns 1, it indicates that the specified file/directory
1298
 * name refers to a `.git` file or directory, or to any of these synonyms, and
1299
 * Git should therefore not track it.
1300
 *
1301
 * For performance reasons, _all_ Alternate Data Streams of `.git/` are
1302
 * forbidden, not just `::$INDEX_ALLOCATION`.
1303
 *
1304
 * This function is intended to be used by `git fsck` even on platforms where
1305
 * the backslash is a regular filename character, therefore it needs to handle
1306
 * backlash characters in the provided `name` specially: they are interpreted
1307
 * as directory separators.
1308
 */
1309
int is_ntfs_dotgit(const char *name)
1310
{
1311
	char c;
1312

1313
	/*
1314
	 * Note that when we don't find `.git` or `git~1` we end up with `name`
1315
	 * advanced partway through the string. That's okay, though, as we
1316
	 * return immediately in those cases, without looking at `name` any
1317
	 * further.
1318
	 */
1319
	c = *(name++);
1320
	if (c == '.') {
1321
		/* .git */
1322
		if (((c = *(name++)) != 'g' && c != 'G') ||
1323
		    ((c = *(name++)) != 'i' && c != 'I') ||
1324
		    ((c = *(name++)) != 't' && c != 'T'))
1325
			return 0;
1326
	} else if (c == 'g' || c == 'G') {
1327
		/* git ~1 */
1328
		if (((c = *(name++)) != 'i' && c != 'I') ||
1329
		    ((c = *(name++)) != 't' && c != 'T') ||
1330
		    *(name++) != '~' ||
1331
		    *(name++) != '1')
1332
			return 0;
1333
	} else
1334
		return 0;
1335

1336
	for (;;) {
1337
		c = *(name++);
1338
		if (!c || is_xplatform_dir_sep(c) || c == ':')
1339
			return 1;
1340
		if (c != '.' && c != ' ')
1341
			return 0;
1342
	}
1343
}
1344

1345
static int is_ntfs_dot_generic(const char *name,
1346
			       const char *dotgit_name,
1347
			       size_t len,
1348
			       const char *dotgit_ntfs_shortname_prefix)
1349
{
1350
	int saw_tilde;
1351
	size_t i;
1352

1353
	if ((name[0] == '.' && !strncasecmp(name + 1, dotgit_name, len))) {
1354
		i = len + 1;
1355
only_spaces_and_periods:
1356
		for (;;) {
1357
			char c = name[i++];
1358
			if (!c || c == ':')
1359
				return 1;
1360
			if (c != ' ' && c != '.')
1361
				return 0;
1362
		}
1363
	}
1364

1365
	/*
1366
	 * Is it a regular NTFS short name, i.e. shortened to 6 characters,
1367
	 * followed by ~1, ... ~4?
1368
	 */
1369
	if (!strncasecmp(name, dotgit_name, 6) && name[6] == '~' &&
1370
	    name[7] >= '1' && name[7] <= '4') {
1371
		i = 8;
1372
		goto only_spaces_and_periods;
1373
	}
1374

1375
	/*
1376
	 * Is it a fall-back NTFS short name (for details, see
1377
	 * https://en.wikipedia.org/wiki/8.3_filename?
1378
	 */
1379
	for (i = 0, saw_tilde = 0; i < 8; i++)
1380
		if (name[i] == '\0')
1381
			return 0;
1382
		else if (saw_tilde) {
1383
			if (name[i] < '0' || name[i] > '9')
1384
				return 0;
1385
		} else if (name[i] == '~') {
1386
			if (name[++i] < '1' || name[i] > '9')
1387
				return 0;
1388
			saw_tilde = 1;
1389
		} else if (i >= 6)
1390
			return 0;
1391
		else if (name[i] & 0x80) {
1392
			/*
1393
			 * We know our needles contain only ASCII, so we clamp
1394
			 * here to make the results of tolower() sane.
1395
			 */
1396
			return 0;
1397
		} else if (tolower(name[i]) != dotgit_ntfs_shortname_prefix[i])
1398
			return 0;
1399

1400
	goto only_spaces_and_periods;
1401
}
1402

1403
/*
1404
 * Inline helper to make sure compiler resolves strlen() on literals at
1405
 * compile time.
1406
 */
1407
static inline int is_ntfs_dot_str(const char *name, const char *dotgit_name,
1408
				  const char *dotgit_ntfs_shortname_prefix)
1409
{
1410
	return is_ntfs_dot_generic(name, dotgit_name, strlen(dotgit_name),
1411
				   dotgit_ntfs_shortname_prefix);
1412
}
1413

1414
int is_ntfs_dotgitmodules(const char *name)
1415
{
1416
	return is_ntfs_dot_str(name, "gitmodules", "gi7eba");
1417
}
1418

1419
int is_ntfs_dotgitignore(const char *name)
1420
{
1421
	return is_ntfs_dot_str(name, "gitignore", "gi250a");
1422
}
1423

1424
int is_ntfs_dotgitattributes(const char *name)
1425
{
1426
	return is_ntfs_dot_str(name, "gitattributes", "gi7d29");
1427
}
1428

1429
int is_ntfs_dotmailmap(const char *name)
1430
{
1431
	return is_ntfs_dot_str(name, "mailmap", "maba30");
1432
}
1433

1434
int looks_like_command_line_option(const char *str)
1435
{
1436
	return str && str[0] == '-';
1437
}
1438

1439
char *xdg_config_home_for(const char *subdir, const char *filename)
1440
{
1441
	const char *home, *config_home;
1442

1443
	assert(subdir);
1444
	assert(filename);
1445
	config_home = getenv("XDG_CONFIG_HOME");
1446
	if (config_home && *config_home)
1447
		return mkpathdup("%s/%s/%s", config_home, subdir, filename);
1448

1449
	home = getenv("HOME");
1450
	if (home)
1451
		return mkpathdup("%s/.config/%s/%s", home, subdir, filename);
1452

1453
	return NULL;
1454
}
1455

1456
char *xdg_config_home(const char *filename)
1457
{
1458
	return xdg_config_home_for("git", filename);
1459
}
1460

1461
char *xdg_cache_home(const char *filename)
1462
{
1463
	const char *home, *cache_home;
1464

1465
	assert(filename);
1466
	cache_home = getenv("XDG_CACHE_HOME");
1467
	if (cache_home && *cache_home)
1468
		return mkpathdup("%s/git/%s", cache_home, filename);
1469

1470
	home = getenv("HOME");
1471
	if (home)
1472
		return mkpathdup("%s/.cache/git/%s", home, filename);
1473
	return NULL;
1474
}
1475

1476
REPO_GIT_PATH_FUNC(squash_msg, "SQUASH_MSG")
1477
REPO_GIT_PATH_FUNC(merge_msg, "MERGE_MSG")
1478
REPO_GIT_PATH_FUNC(merge_rr, "MERGE_RR")
1479
REPO_GIT_PATH_FUNC(merge_mode, "MERGE_MODE")
1480
REPO_GIT_PATH_FUNC(merge_head, "MERGE_HEAD")
1481
REPO_GIT_PATH_FUNC(fetch_head, "FETCH_HEAD")
1482
REPO_GIT_PATH_FUNC(shallow, "shallow")
1483