config_file.c 40.5 KB
Newer Older
1
/*
Edward Thomson committed
2
 * Copyright (C) the libgit2 contributors. All rights reserved.
3
 *
Vicent Marti committed
4 5
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
6 7 8 9
 */

#include "common.h"
#include "config.h"
10
#include "filebuf.h"
11
#include "sysdir.h"
12
#include "buffer.h"
13
#include "buf_text.h"
14
#include "git2/config.h"
15
#include "git2/sys/config.h"
16
#include "git2/types.h"
17
#include "strmap.h"
18
#include "array.h"
19

20
#include <ctype.h>
21 22
#include <sys/types.h>
#include <regex.h>
23

24
GIT__USE_STRMAP;
25

26 27
typedef struct cvar_t {
	struct cvar_t *next;
28
	git_config_entry *entry;
29
	bool included; /* whether this is part of [include] */
30
} cvar_t;
31

32
typedef struct git_config_file_iter {
33
	git_config_iterator parent;
34
	git_strmap_iter iter;
35
	cvar_t* next_var;
36 37
} git_config_file_iter;

38 39
/* Max depth for [include] directives */
#define MAX_INCLUDE_DEPTH 10
40

41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
#define CVAR_LIST_HEAD(list) ((list)->head)

#define CVAR_LIST_TAIL(list) ((list)->tail)

#define CVAR_LIST_NEXT(var) ((var)->next)

#define CVAR_LIST_EMPTY(list) ((list)->head == NULL)

#define CVAR_LIST_APPEND(list, var) do {\
	if (CVAR_LIST_EMPTY(list)) {\
		CVAR_LIST_HEAD(list) = CVAR_LIST_TAIL(list) = var;\
	} else {\
		CVAR_LIST_NEXT(CVAR_LIST_TAIL(list)) = var;\
		CVAR_LIST_TAIL(list) = var;\
	}\
} while(0)

#define CVAR_LIST_REMOVE_HEAD(list) do {\
	CVAR_LIST_HEAD(list) = CVAR_LIST_NEXT(CVAR_LIST_HEAD(list));\
} while(0)

#define CVAR_LIST_REMOVE_AFTER(var) do {\
	CVAR_LIST_NEXT(var) = CVAR_LIST_NEXT(CVAR_LIST_NEXT(var));\
} while(0)

#define CVAR_LIST_FOREACH(list, iter)\
	for ((iter) = CVAR_LIST_HEAD(list);\
		 (iter) != NULL;\
		 (iter) = CVAR_LIST_NEXT(iter))

/*
 * Inspired by the FreeBSD functions
 */
#define CVAR_LIST_FOREACH_SAFE(start, iter, tmp)\
	for ((iter) = CVAR_LIST_HEAD(vars);\
		 (iter) && (((tmp) = CVAR_LIST_NEXT(iter) || 1));\
		 (iter) = (tmp))

79
struct reader {
80 81
	time_t file_mtime;
	size_t file_size;
82 83 84 85 86 87 88
	char *file_path;
	git_buf buffer;
	char *read_ptr;
	int line_number;
	int eof;
};

89
typedef struct {
90
	git_atomic refcount;
91
	git_strmap *values;
92 93 94 95 96 97 98
} refcounted_strmap;

typedef struct {
	git_config_backend parent;
	/* mutex to coordinate accessing the values */
	git_mutex values_mutex;
	refcounted_strmap *values;
99
	int readonly;
100 101 102 103 104 105
} diskfile_header;

typedef struct {
	diskfile_header header;

	git_config_level_t level;
106

107
	git_array_t(struct reader) readers;
108

109
	char  *file_path;
110
} diskfile_backend;
111

112 113 114 115 116 117
typedef struct {
	diskfile_header header;

	diskfile_backend *snapshot_from;
} diskfile_readonly_backend;

118
static int config_parse(git_strmap *values, diskfile_backend *cfg_file, struct reader *reader, git_config_level_t level, int depth);
119
static int parse_variable(struct reader *reader, char **var_name, char **var_value);
120
static int config_write(diskfile_backend *cfg, const char *key, const regex_t *preg, const char *value);
121
static char *escape_value(const char *ptr);
122

123
int git_config_file__snapshot(git_config_backend **out, diskfile_backend *in);
124
static int config_snapshot(git_config_backend **out, git_config_backend *in);
125

126
static void set_parse_error(struct reader *reader, int col, const char *error_str)
127 128
{
	giterr_set(GITERR_CONFIG, "Failed to parse config file: %s (in %s:%d, column %d)",
129
		error_str, reader->file_path, reader->line_number, col);
130 131
}

132 133 134 135 136 137
static int config_error_readonly(void)
{
	giterr_set(GITERR_CONFIG, "this backend is read-only");
	return -1;
}

138
static void cvar_free(cvar_t *var)
139 140 141 142
{
	if (var == NULL)
		return;

143 144 145
	git__free((char*)var->entry->name);
	git__free((char *)var->entry->value);
	git__free(var->entry);
146
	git__free(var);
147 148
}

149 150 151 152 153 154 155 156 157 158 159 160
int git_config_file_normalize_section(char *start, char *end)
{
	char *scan;

	if (start == end)
		return GIT_EINVALIDSPEC;

	/* Validate and downcase range */
	for (scan = start; *scan; ++scan) {
		if (end && scan >= end)
			break;
		if (isalnum(*scan))
Linquize committed
161
			*scan = (char)tolower(*scan);
162 163 164 165 166 167 168 169 170 171
		else if (*scan != '-' || scan == start)
			return GIT_EINVALIDSPEC;
	}

	if (scan == start)
		return GIT_EINVALIDSPEC;

	return 0;
}

172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195
/* Add or append the new config option */
static int append_entry(git_strmap *values, cvar_t *var)
{
	git_strmap_iter pos;
	cvar_t *existing;
	int error = 0;

	pos = git_strmap_lookup_index(values, var->entry->name);
	if (!git_strmap_valid_index(values, pos)) {
		git_strmap_insert(values, var->entry->name, var, error);
	} else {
		existing = git_strmap_value_at(values, pos);
		while (existing->next != NULL) {
			existing = existing->next;
		}
		existing->next = var;
	}

	if (error > 0)
		error = 0;

	return error;
}

196
static void free_vars(git_strmap *values)
197
{
198
	cvar_t *var = NULL;
199

200 201
	if (values == NULL)
		return;
202

203
	git_strmap_foreach_value(values, var,
204 205 206 207 208
		while (var != NULL) {
			cvar_t *next = CVAR_LIST_NEXT(var);
			cvar_free(var);
			var = next;
		});
209

210
	git_strmap_free(values);
211 212
}

213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249
static void refcounted_strmap_free(refcounted_strmap *map)
{
	if (!map)
		return;

	if (git_atomic_dec(&map->refcount) != 0)
		return;

	free_vars(map->values);
	git__free(map);
}

/**
 * Take the current values map from the backend and increase its
 * refcount. This is its own function to make sure we use the mutex to
 * avoid the map pointer from changing under us.
 */
static refcounted_strmap *refcounted_strmap_take(diskfile_header *h)
{
	refcounted_strmap *map;

	git_mutex_lock(&h->values_mutex);

	map = h->values;
	git_atomic_inc(&map->refcount);

	git_mutex_unlock(&h->values_mutex);

	return map;
}

static int refcounted_strmap_alloc(refcounted_strmap **out)
{
	refcounted_strmap *map;
	int error;

	map = git__calloc(1, sizeof(refcounted_strmap));
250
	GITERR_CHECK_ALLOC(map);
251 252

	git_atomic_set(&map->refcount, 1);
253 254

	if ((error = git_strmap_alloc(&map->values)) < 0)
255
		git__free(map);
256 257
	else
		*out = map;
258 259 260 261

	return error;
}

262
static int config_open(git_config_backend *cfg, git_config_level_t level)
263
{
264
	int res;
265
	struct reader *reader;
266
	diskfile_backend *b = (diskfile_backend *)cfg;
267

268 269
	b->level = level;

270
	if ((res = refcounted_strmap_alloc(&b->header.values)) < 0)
271
		return res;
272

273 274
	git_array_init(b->readers);
	reader = git_array_alloc(b->readers);
275
	if (!reader) {
276
		refcounted_strmap_free(b->header.values);
277 278
		return -1;
	}
279 280 281 282 283 284
	memset(reader, 0, sizeof(struct reader));

	reader->file_path = git__strdup(b->file_path);
	GITERR_CHECK_ALLOC(reader->file_path);

	git_buf_init(&reader->buffer, 0);
285
	res = git_futils_readbuffer_updated(
286
		&reader->buffer, b->file_path, &reader->file_mtime, &reader->file_size, NULL);
287

288
	/* It's fine if the file doesn't exist */
289 290 291
	if (res == GIT_ENOTFOUND)
		return 0;

292 293
	if (res < 0 || (res = config_parse(b->header.values->values, b, reader, level, 0)) < 0) {
		refcounted_strmap_free(b->header.values);
294
		b->header.values = NULL;
295
	}
296

297
	reader = git_array_get(b->readers, 0);
298
	git_buf_free(&reader->buffer);
299

300 301 302
	return res;
}

303 304 305
/* The meat of the refresh, as we want to use it in different places */
static int config__refresh(git_config_backend *cfg)
{
306
	refcounted_strmap *values = NULL, *tmp;
307 308 309 310
	diskfile_backend *b = (diskfile_backend *)cfg;
	struct reader *reader = NULL;
	int error = 0;

311
	if ((error = refcounted_strmap_alloc(&values)) < 0)
312 313 314
		goto out;

	reader = git_array_get(b->readers, git_array_size(b->readers) - 1);
315
	GITERR_CHECK_ALLOC(reader);
316

317
	if ((error = config_parse(values->values, b, reader, b->level, 0)) < 0)
318 319
		goto out;

320 321 322 323 324 325 326
	git_mutex_lock(&b->header.values_mutex);

	tmp = b->header.values;
	b->header.values = values;
	values = tmp;

	git_mutex_unlock(&b->header.values_mutex);
327 328

out:
329
	refcounted_strmap_free(values);
330 331
	if (reader)
		git_buf_free(&reader->buffer);
332 333 334
	return error;
}

Ben Straub committed
335
static int config_refresh(git_config_backend *cfg)
336
{
337
	int error = 0, updated = 0, any_updated = 0;
338
	diskfile_backend *b = (diskfile_backend *)cfg;
339
	struct reader *reader = NULL;
340
	uint32_t i;
341

342 343
	for (i = 0; i < git_array_size(b->readers); i++) {
		reader = git_array_get(b->readers, i);
344
		error = git_futils_readbuffer_updated(
345 346
			&reader->buffer, reader->file_path,
			&reader->file_mtime, &reader->file_size, &updated);
347

348 349
		if (error < 0 && error != GIT_ENOTFOUND)
			return error;
350 351 352 353 354 355

		if (updated)
			any_updated = 1;
	}

	if (!any_updated)
356
		return (error == GIT_ENOTFOUND) ? 0 : error;
357

358
	return config__refresh(cfg);
359 360
}

Ben Straub committed
361
static void backend_free(git_config_backend *_backend)
362
{
363
	diskfile_backend *backend = (diskfile_backend *)_backend;
364
	uint32_t i;
365 366 367 368

	if (backend == NULL)
		return;

369 370 371 372 373 374
	for (i = 0; i < git_array_size(backend->readers); i++) {
		struct reader *r = git_array_get(backend->readers, i);
		git__free(r->file_path);
	}
	git_array_clear(backend->readers);

375
	git__free(backend->file_path);
376
	refcounted_strmap_free(backend->header.values);
377
	git_mutex_free(&backend->header.values_mutex);
378
	git__free(backend);
379 380
}

381
static void config_iterator_free(
382
	git_config_iterator* iter)
383
{
384
	iter->backend->free(iter->backend);
385 386
	git__free(iter);
}
387

388
static int config_iterator_next(
389
	git_config_entry **entry,
390
	git_config_iterator *iter)
391
{
392
	git_config_file_iter *it = (git_config_file_iter *) iter;
393
	diskfile_header *h = (diskfile_header *) it->parent.backend;
394
	git_strmap *values = h->values->values;
395
	int err = 0;
396
	cvar_t * var;
397

398
	if (it->next_var == NULL) {
399
		err = git_strmap_next((void**) &var, &(it->iter), values);
400
	} else {
401
		var = it->next_var;
402
	}
403

404
	if (err < 0) {
405
		it->next_var = NULL;
406
		return err;
407
	}
408

409
	*entry = var->entry;
410
	it->next_var = CVAR_LIST_NEXT(var);
411

412 413
	return 0;
}
414

415 416 417 418
static int config_iterator_new(
	git_config_iterator **iter,
	struct git_config_backend* backend)
{
419 420 421 422 423
	diskfile_header *h;
	git_config_file_iter *it;
	git_config_backend *snapshot;
	diskfile_backend *b = (diskfile_backend *) backend;
	int error;
424

425 426 427 428 429 430 431
	if ((error = config_snapshot(&snapshot, backend)) < 0)
		return error;

	if ((error = snapshot->open(snapshot, b->level)) < 0)
		return error;

	it = git__calloc(1, sizeof(git_config_file_iter));
432 433
	GITERR_CHECK_ALLOC(it);

434 435
	h = (diskfile_header *)snapshot;

436 437 438
	/* strmap_begin() is currently a macro returning 0 */
	GIT_UNUSED(h);

439
	it->parent.backend = snapshot;
440
	it->iter = git_strmap_begin(h->values);
441 442 443 444 445
	it->next_var = NULL;

	it->parent.next = config_iterator_next;
	it->parent.free = config_iterator_free;
	*iter = (git_config_iterator *) it;
446 447

	return 0;
448 449
}

Ben Straub committed
450
static int config_set(git_config_backend *cfg, const char *name, const char *value)
451
{
452
	diskfile_backend *b = (diskfile_backend *)cfg;
453 454
	refcounted_strmap *map;
	git_strmap *values;
455
	char *key, *esc_value = NULL;
456
	khiter_t pos;
457
	int rval, ret;
458

459
	if ((rval = git_config__normalize_name(name, &key)) < 0)
460
		return rval;
461

462 463 464
	map = refcounted_strmap_take(&b->header);
	values = map->values;

465
	/*
466 467
	 * Try to find it in the existing values and update it if it
	 * only has one value.
468
	 */
469 470 471
	pos = git_strmap_lookup_index(values, key);
	if (git_strmap_valid_index(values, pos)) {
		cvar_t *existing = git_strmap_value_at(values, pos);
Russell Belfer committed
472

473 474
		if (existing->next != NULL) {
			giterr_set(GITERR_CONFIG, "Multivar incompatible with simple set");
475 476
			ret = -1;
			goto out;
477
		}
478

Russell Belfer committed
479
		/* don't update if old and new values already match */
480
		if ((!existing->entry->value && !value) ||
481 482
			(existing->entry->value && value &&
			 !strcmp(existing->entry->value, value))) {
483 484
			ret = 0;
			goto out;
485
		}
486 487
	}

488
	/* No early returns due to sanity checks, let's write it out and refresh */
489

490
	if (value) {
491 492
		esc_value = escape_value(value);
		GITERR_CHECK_ALLOC(esc_value);
493 494
	}

495 496
	if ((ret = config_write(b, key, NULL, esc_value)) < 0)
		goto out;
497

498
	ret = config_refresh(cfg);
499

500
out:
501
	refcounted_strmap_free(map);
502 503 504
	git__free(esc_value);
	git__free(key);
	return ret;
505 506 507 508 509
}

/*
 * Internal function that actually gets the value in string form
 */
510
static int config_get(git_config_backend *cfg, const char *key, const git_config_entry **out)
511
{
512
	diskfile_header *h = (diskfile_header *)cfg;
513
	refcounted_strmap *map;
514 515
	git_strmap *values;
	khiter_t pos;
516
	cvar_t *var;
517 518 519 520 521
	int error;

	if (!h->readonly && ((error = config_refresh(cfg)) < 0))
		return error;

522 523 524
	map = refcounted_strmap_take(h);
	values = map->values;

525
	pos = git_strmap_lookup_index(values, key);
526

527
	/* no error message; the config system will write one */
528 529
	if (!git_strmap_valid_index(values, pos)) {
		refcounted_strmap_free(map);
530
		return GIT_ENOTFOUND;
531
	}
532

533
	var = git_strmap_value_at(values, pos);
534 535 536
	while (var->next)
		var = var->next;

537
	refcounted_strmap_free(map);
538
	*out = var->entry;
539
	return 0;
540 541
}

542
static int config_set_multivar(
Ben Straub committed
543
	git_config_backend *cfg, const char *name, const char *regexp, const char *value)
544 545
{
	diskfile_backend *b = (diskfile_backend *)cfg;
546 547
	refcounted_strmap *map;
	git_strmap *values;
548 549
	char *key;
	regex_t preg;
550
	int result;
551
	khiter_t pos;
552

553
	assert(regexp);
554

555
	if ((result = git_config__normalize_name(name, &key)) < 0)
556
		return result;
557

558 559 560
	map = refcounted_strmap_take(&b->header);
	values = b->header.values->values;

561 562
	pos = git_strmap_lookup_index(values, key);
	if (!git_strmap_valid_index(values, pos)) {
563 564
		/* If we don't have it, behave like a normal set */
		result = config_set(cfg, name, value);
565
		refcounted_strmap_free(map);
566
		git__free(key);
567
		return result;
568
	}
569

570 571 572
	result = regcomp(&preg, regexp, REG_EXTENDED);
	if (result < 0) {
		giterr_set_regex(&preg, result);
573 574
		result = -1;
		goto out;
575
	}
576

577 578 579
	/* If we do have it, set call config_write() and reload */
	if ((result = config_write(b, key, &preg, value)) < 0)
		goto out;
580

581
	result = config_refresh(cfg);
582

583
out:
584
	refcounted_strmap_free(map);
585
	git__free(key);
586
	regfree(&preg);
587 588

	return result;
589 590
}

Ben Straub committed
591
static int config_delete(git_config_backend *cfg, const char *name)
592
{
593
	cvar_t *var;
594
	diskfile_backend *b = (diskfile_backend *)cfg;
595
	refcounted_strmap *map;	git_strmap *values;
596
	char *key;
597
	int result;
598
	khiter_t pos;
599

600
	if ((result = git_config__normalize_name(name, &key)) < 0)
601
		return result;
602

603 604 605
	map = refcounted_strmap_take(&b->header);
	values = b->header.values->values;

606
	pos = git_strmap_lookup_index(values, key);
607
	git__free(key);
608

609
	if (!git_strmap_valid_index(values, pos)) {
610
		refcounted_strmap_free(map);
611
		giterr_set(GITERR_CONFIG, "Could not find key '%s' to delete", name);
612
		return GIT_ENOTFOUND;
613
	}
614

615
	var = git_strmap_value_at(values, pos);
616
	refcounted_strmap_free(map);
617

618 619 620 621
	if (var->next != NULL) {
		giterr_set(GITERR_CONFIG, "Cannot delete multivar with a single delete");
		return -1;
	}
622

623 624
	if ((result = config_write(b, var->entry->name, NULL, NULL)) < 0)
		return result;
625

626
	return config_refresh(cfg);
627 628
}

629 630 631
static int config_delete_multivar(git_config_backend *cfg, const char *name, const char *regexp)
{
	diskfile_backend *b = (diskfile_backend *)cfg;
632 633
	refcounted_strmap *map;
	git_strmap *values;
634 635 636 637 638 639 640 641
	char *key;
	regex_t preg;
	int result;
	khiter_t pos;

	if ((result = git_config__normalize_name(name, &key)) < 0)
		return result;

642 643 644
	map = refcounted_strmap_take(&b->header);
	values = b->header.values->values;

645
	pos = git_strmap_lookup_index(values, key);
646

647
	if (!git_strmap_valid_index(values, pos)) {
648
		refcounted_strmap_free(map);
649
		git__free(key);
650
		giterr_set(GITERR_CONFIG, "Could not find key '%s' to delete", name);
651 652 653
		return GIT_ENOTFOUND;
	}

654 655
	refcounted_strmap_free(map);

656 657 658
	result = regcomp(&preg, regexp, REG_EXTENDED);
	if (result < 0) {
		giterr_set_regex(&preg, result);
659 660
		result = -1;
		goto out;
661 662
	}

663 664
	if ((result = config_write(b, key, &preg, NULL)) < 0)
		goto out;
665

666
	result = config_refresh(cfg);
667

668
out:
669
	git__free(key);
670
	regfree(&preg);
671 672 673
	return result;
}

674 675 676 677 678 679 680
static int config_snapshot(git_config_backend **out, git_config_backend *in)
{
	diskfile_backend *b = (diskfile_backend *) in;

	return git_config_file__snapshot(out, b);
}

Ben Straub committed
681
int git_config_file__ondisk(git_config_backend **out, const char *path)
682
{
683
	diskfile_backend *backend;
684

685
	backend = git__calloc(1, sizeof(diskfile_backend));
686
	GITERR_CHECK_ALLOC(backend);
687

688
	backend->header.parent.version = GIT_CONFIG_BACKEND_VERSION;
689
	git_mutex_init(&backend->header.values_mutex);
690 691

	backend->file_path = git__strdup(path);
692
	GITERR_CHECK_ALLOC(backend->file_path);
693

694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760
	backend->header.parent.open = config_open;
	backend->header.parent.get = config_get;
	backend->header.parent.set = config_set;
	backend->header.parent.set_multivar = config_set_multivar;
	backend->header.parent.del = config_delete;
	backend->header.parent.del_multivar = config_delete_multivar;
	backend->header.parent.iterator = config_iterator_new;
	backend->header.parent.refresh = config_refresh;
	backend->header.parent.snapshot = config_snapshot;
	backend->header.parent.free = backend_free;

	*out = (git_config_backend *)backend;

	return 0;
}

static int config_set_readonly(git_config_backend *cfg, const char *name, const char *value)
{
	GIT_UNUSED(cfg);
	GIT_UNUSED(name);
	GIT_UNUSED(value);

	return config_error_readonly();
}

static int config_set_multivar_readonly(
	git_config_backend *cfg, const char *name, const char *regexp, const char *value)
{
	GIT_UNUSED(cfg);
	GIT_UNUSED(name);
	GIT_UNUSED(regexp);
	GIT_UNUSED(value);

	return config_error_readonly();
}

static int config_delete_multivar_readonly(git_config_backend *cfg, const char *name, const char *regexp)
{
	GIT_UNUSED(cfg);
	GIT_UNUSED(name);
	GIT_UNUSED(regexp);

	return config_error_readonly();
}

static int config_delete_readonly(git_config_backend *cfg, const char *name)
{
	GIT_UNUSED(cfg);
	GIT_UNUSED(name);

	return config_error_readonly();
}

static int config_refresh_readonly(git_config_backend *cfg)
{
	GIT_UNUSED(cfg);

	return config_error_readonly();
}

static void backend_readonly_free(git_config_backend *_backend)
{
	diskfile_backend *backend = (diskfile_backend *)_backend;

	if (backend == NULL)
		return;

761
	refcounted_strmap_free(backend->header.values);
762
	git_mutex_free(&backend->header.values_mutex);
763 764 765 766 767 768 769
	git__free(backend);
}

static int config_readonly_open(git_config_backend *cfg, git_config_level_t level)
{
	diskfile_readonly_backend *b = (diskfile_readonly_backend *) cfg;
	diskfile_backend *src = b->snapshot_from;
770
	refcounted_strmap *src_map;
771 772 773 774

	/* We're just copying data, don't care about the level */
	GIT_UNUSED(level);

775
	src_map = refcounted_strmap_take(&src->header);
776
	b->header.values = src_map;
777

778
	return 0;
779 780 781 782 783 784 785 786 787 788
}

int git_config_file__snapshot(git_config_backend **out, diskfile_backend *in)
{
	diskfile_readonly_backend *backend;

	backend = git__calloc(1, sizeof(diskfile_readonly_backend));
	GITERR_CHECK_ALLOC(backend);

	backend->header.parent.version = GIT_CONFIG_BACKEND_VERSION;
789
	git_mutex_init(&backend->header.values_mutex);
790 791 792

	backend->snapshot_from = in;

793
	backend->header.readonly = 1;
794 795 796 797 798 799 800 801 802 803
	backend->header.parent.version = GIT_CONFIG_BACKEND_VERSION;
	backend->header.parent.open = config_readonly_open;
	backend->header.parent.get = config_get;
	backend->header.parent.set = config_set_readonly;
	backend->header.parent.set_multivar = config_set_multivar_readonly;
	backend->header.parent.del = config_delete_readonly;
	backend->header.parent.del_multivar = config_delete_multivar_readonly;
	backend->header.parent.iterator = config_iterator_new;
	backend->header.parent.refresh = config_refresh_readonly;
	backend->header.parent.free = backend_readonly_free;
804

Ben Straub committed
805
	*out = (git_config_backend *)backend;
806

807
	return 0;
808 809
}

810
static int reader_getchar_raw(struct reader *reader)
811 812 813
{
	int c;

814
	c = *reader->read_ptr++;
815 816 817 818 819

	/*
	Win 32 line breaks: if we find a \r\n sequence,
	return only the \n as a newline
	*/
820 821
	if (c == '\r' && *reader->read_ptr == '\n') {
		reader->read_ptr++;
822 823 824 825
		c = '\n';
	}

	if (c == '\n')
826
		reader->line_number++;
827 828

	if (c == 0) {
829
		reader->eof = 1;
830 831 832 833 834 835 836 837 838
		c = '\n';
	}

	return c;
}

#define SKIP_WHITESPACE (1 << 1)
#define SKIP_COMMENTS (1 << 2)

839
static int reader_getchar(struct reader *reader, int flags)
840 841 842 843 844
{
	const int skip_whitespace = (flags & SKIP_WHITESPACE);
	const int skip_comments = (flags & SKIP_COMMENTS);
	int c;

845
	assert(reader->read_ptr);
846

847 848 849 850
	do {
		c = reader_getchar_raw(reader);
	} while (skip_whitespace && git__isspace(c) &&
	       !reader->eof);
851 852

	if (skip_comments && (c == '#' || c == ';')) {
853 854 855
		do {
			c = reader_getchar_raw(reader);
		} while (c != '\n');
856 857 858 859 860 861 862 863
	}

	return c;
}

/*
 * Read the next char, but don't move the reading pointer.
 */
864
static int reader_peek(struct reader *reader, int flags)
865 866 867 868 869
{
	void *old_read_ptr;
	int old_lineno, old_eof;
	int ret;

870
	assert(reader->read_ptr);
871

872 873 874
	old_read_ptr = reader->read_ptr;
	old_lineno = reader->line_number;
	old_eof = reader->eof;
875

876
	ret = reader_getchar(reader, flags);
877

878 879 880
	reader->read_ptr = old_read_ptr;
	reader->line_number = old_lineno;
	reader->eof = old_eof;
881 882 883 884 885 886 887

	return ret;
}

/*
 * Read and consume a line, returning it in newly-allocated memory.
 */
888
static char *reader_readline(struct reader *reader, bool skip_whitespace)
889 890 891
{
	char *line = NULL;
	char *line_src, *line_end;
892
	size_t line_len;
893

894
	line_src = reader->read_ptr;
895

896 897
	if (skip_whitespace) {
		/* Skip empty empty lines */
898
		while (git__isspace(*line_src))
899 900
			++line_src;
	}
901

902
	line_end = strchr(line_src, '\n');
903

904
	/* no newline at EOF */
905 906 907
	if (line_end == NULL)
		line_end = strchr(line_src, 0);

908
	line_len = line_end - line_src;
909

910
	line = git__malloc(line_len + 1);
911 912 913
	if (line == NULL)
		return NULL;

914
	memcpy(line, line_src, line_len);
915

916
	do line[line_len] = '\0';
917
	while (line_len-- > 0 && git__isspace(line[line_len]));
918 919 920 921 922

	if (*line_end == '\n')
		line_end++;

	if (*line_end == '\0')
923
		reader->eof = 1;
924

925 926
	reader->line_number++;
	reader->read_ptr = line_end;
927 928 929 930 931 932 933

	return line;
}

/*
 * Consume a line, without storing it anywhere
 */
934
static void reader_consume_line(struct reader *reader)
935 936 937
{
	char *line_start, *line_end;

938
	line_start = reader->read_ptr;
939 940 941 942 943 944 945 946 947 948
	line_end = strchr(line_start, '\n');
	/* No newline at EOF */
	if(line_end == NULL){
		line_end = strchr(line_start, '\0');
	}

	if (*line_end == '\n')
		line_end++;

	if (*line_end == '\0')
949
		reader->eof = 1;
950

951 952
	reader->line_number++;
	reader->read_ptr = line_end;
953 954
}

955
GIT_INLINE(int) config_keychar(int c)
956 957 958 959
{
	return isalnum(c) || c == '-';
}

960
static int parse_section_header_ext(struct reader *reader, const char *line, const char *base_name, char **section_name)
961
{
962 963 964
	int c, rpos;
	char *first_quote, *last_quote;
	git_buf buf = GIT_BUF_INIT;
965 966 967 968 969 970 971 972 973
	/*
	 * base_name is what came before the space. We should be at the
	 * first quotation mark, except for now, line isn't being kept in
	 * sync so we only really use it to calculate the length.
	 */

	first_quote = strchr(line, '"');
	last_quote = strrchr(line, '"');

974
	if (last_quote - first_quote == 0) {
975
		set_parse_error(reader, 0, "Missing closing quotation mark in section header");
976 977
		return -1;
	}
978

979 980
	git_buf_grow(&buf, strlen(base_name) + last_quote - first_quote + 2);
	git_buf_printf(&buf, "%s.", base_name);
981 982 983 984

	rpos = 0;

	line = first_quote;
985
	c = line[++rpos];
986 987 988 989 990 991

	/*
	 * At the end of each iteration, whatever is stored in c will be
	 * added to the string. In case of error, jump to out
	 */
	do {
992

993
		switch (c) {
994
		case 0:
995
			set_parse_error(reader, 0, "Unexpected end-of-line in section header");
996 997 998
			git_buf_free(&buf);
			return -1;

999
		case '"':
1000
			goto end_parse;
1001

1002
		case '\\':
1003
			c = line[++rpos];
1004

1005 1006
			if (c == 0) {
				set_parse_error(reader, rpos, "Unexpected end-of-line in section header");
1007 1008
				git_buf_free(&buf);
				return -1;
1009
			}
1010

1011 1012 1013 1014
		default:
			break;
		}

Linquize committed
1015
		git_buf_putc(&buf, (char)c);
1016 1017 1018 1019 1020 1021 1022 1023 1024
		c = line[++rpos];
	} while (line + rpos < last_quote);

end_parse:
	if (line[rpos] != '"' || line[rpos + 1] != ']') {
		set_parse_error(reader, rpos, "Unexpected text after closing quotes");
		git_buf_free(&buf);
		return -1;
	}
1025

1026 1027
	*section_name = git_buf_detach(&buf);
	return 0;
1028 1029
}

1030
static int parse_section_header(struct reader *reader, char **section_out)
1031 1032 1033
{
	char *name, *name_end;
	int name_length, c, pos;
1034
	int result;
1035 1036
	char *line;

1037
	line = reader_readline(reader, true);
1038
	if (line == NULL)
1039
		return -1;
1040 1041

	/* find the end of the variable's name */
1042
	name_end = strrchr(line, ']');
schu committed
1043
	if (name_end == NULL) {
1044
		git__free(line);
1045
		set_parse_error(reader, 0, "Missing ']' in section header");
1046
		return -1;
schu committed
1047
	}
1048 1049

	name = (char *)git__malloc((size_t)(name_end - line) + 1);
1050
	GITERR_CHECK_ALLOC(name);
1051 1052 1053 1054 1055 1056

	name_length = 0;
	pos = 0;

	/* Make sure we were given a section header */
	c = line[pos++];
1057
	assert(c == '[');
1058 1059 1060 1061

	c = line[pos++];

	do {
1062
		if (git__isspace(c)){
1063
			name[name_length] = '\0';
1064
			result = parse_section_header_ext(reader, line, name, section_out);
1065 1066
			git__free(line);
			git__free(name);
1067
			return result;
1068 1069 1070
		}

		if (!config_keychar(c) && c != '.') {
1071
			set_parse_error(reader, pos, "Unexpected character in header");
1072
			goto fail_parse;
1073 1074
		}

1075
		name[name_length++] = (char) tolower(c);
1076 1077 1078

	} while ((c = line[pos++]) != ']');

schu committed
1079
	if (line[pos - 1] != ']') {
1080
		set_parse_error(reader, pos, "Unexpected end of file");
1081
		goto fail_parse;
schu committed
1082
	}
1083

1084
	git__free(line);
1085 1086

	name[name_length] = 0;
1087 1088
	*section_out = name;

1089 1090 1091
	return 0;

fail_parse:
1092 1093
	git__free(line);
	git__free(name);
1094
	return -1;
1095 1096
}

1097
static int skip_bom(struct reader *reader)
1098
{
1099 1100
	git_bom_t bom;
	int bom_offset = git_buf_text_detect_bom(&bom,
1101
		&reader->buffer, reader->read_ptr - reader->buffer.ptr);
1102

1103
	if (bom == GIT_BOM_UTF8)
1104
		reader->read_ptr += bom_offset;
1105

1106
	/* TODO: reference implementation is pretty stupid with BoM */
1107

1108
	return 0;
1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149
}

/*
	(* basic types *)
	digit = "0".."9"
	integer = digit { digit }
	alphabet = "a".."z" + "A" .. "Z"

	section_char = alphabet | "." | "-"
	extension_char = (* any character except newline *)
	any_char = (* any character *)
	variable_char = "alphabet" | "-"


	(* actual grammar *)
	config = { section }

	section = header { definition }

	header = "[" section [subsection | subsection_ext] "]"

	subsection = "." section
	subsection_ext = "\"" extension "\""

	section = section_char { section_char }
	extension = extension_char { extension_char }

	definition = variable_name ["=" variable_value] "\n"

	variable_name = variable_char { variable_char }
	variable_value = string | boolean | integer

	string = quoted_string | plain_string
	quoted_string = "\"" plain_string "\""
	plain_string = { any_char }

	boolean = boolean_true | boolean_false
	boolean_true = "yes" | "1" | "true" | "on"
	boolean_false = "no" | "0" | "false" | "off"
*/

1150
static int strip_comments(char *line, int in_quotes)
1151
{
1152
	int quote_count = in_quotes;
1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
	char *ptr;

	for (ptr = line; *ptr; ++ptr) {
		if (ptr[0] == '"' && ptr > line && ptr[-1] != '\\')
			quote_count++;

		if ((ptr[0] == ';' || ptr[0] == '#') && (quote_count % 2) == 0) {
			ptr[0] = '\0';
			break;
		}
	}

1165
	/* skip any space at the end */
1166
	while (ptr > line && git__isspace(ptr[-1])) {
1167
		ptr--;
1168
	}
1169 1170 1171
	ptr[0] = '\0';

	return quote_count;
1172 1173
}

1174 1175 1176 1177
static int included_path(git_buf *out, const char *dir, const char *path)
{
	/* From the user's home */
	if (path[0] == '~' && path[1] == '/')
1178
		return git_sysdir_find_global_file(out, &path[1]);
1179 1180 1181 1182

	return git_path_join_unrooted(out, path, dir, NULL);
}

1183
static int config_parse(git_strmap *values, diskfile_backend *cfg_file, struct reader *reader, git_config_level_t level, int depth)
1184
{
1185
	int c;
1186 1187 1188
	char *current_section = NULL;
	char *var_name;
	char *var_value;
1189
	cvar_t *var;
1190
	git_buf buf = GIT_BUF_INIT;
1191
	int result = 0;
1192
	uint32_t reader_idx;
1193

1194 1195 1196 1197
	if (depth >= MAX_INCLUDE_DEPTH) {
		giterr_set(GITERR_CONFIG, "Maximum config include depth reached");
		return -1;
	}
1198

1199
	reader_idx = git_array_size(cfg_file->readers) - 1;
1200
	/* Initialize the reading position */
1201 1202
	reader->read_ptr = reader->buffer.ptr;
	reader->eof = 0;
1203

1204
	/* If the file is empty, there's nothing for us to do */
1205
	if (*reader->read_ptr == '\0')
1206
		return 0;
1207

1208
	skip_bom(reader);
1209

1210
	while (result == 0 && !reader->eof) {
1211

1212
		c = reader_peek(reader, SKIP_WHITESPACE);
1213 1214

		switch (c) {
1215
		case '\n': /* EOF when peeking, set EOF in the reader to exit the loop */
1216
			reader->eof = 1;
1217 1218 1219
			break;

		case '[': /* section header, new section begins */
1220
			git__free(current_section);
1221
			current_section = NULL;
1222
			result = parse_section_header(reader, &current_section);
1223 1224 1225 1226
			break;

		case ';':
		case '#':
1227
			reader_consume_line(reader);
1228 1229 1230
			break;

		default: /* assume variable declaration */
1231
			result = parse_variable(reader, &var_name, &var_value);
1232
			if (result < 0)
1233 1234
				break;

1235
			var = git__malloc(sizeof(cvar_t));
1236
			GITERR_CHECK_ALLOC(var);
1237
			memset(var, 0x0, sizeof(cvar_t));
1238 1239 1240
			var->entry = git__malloc(sizeof(git_config_entry));
			GITERR_CHECK_ALLOC(var->entry);
			memset(var->entry, 0x0, sizeof(git_config_entry));
1241

1242 1243 1244 1245
			git__strtolower(var_name);
			git_buf_printf(&buf, "%s.%s", current_section, var_name);
			git__free(var_name);

1246 1247
			if (git_buf_oom(&buf)) {
				git__free(var_value);
1248
				return -1;
1249
			}
1250

1251 1252 1253
			var->entry->name = git_buf_detach(&buf);
			var->entry->value = var_value;
			var->entry->level = level;
1254
			var->included = !!depth;
1255

1256 1257 1258 1259

			if ((result = append_entry(values, var)) < 0)
				break;
			else
1260
				result = 0;
1261

1262
			/* Add or append the new config option */
1263
			if (!git__strcmp(var->entry->name, "include.path")) {
1264
				struct reader *r;
1265 1266
				git_buf path = GIT_BUF_INIT;
				char *dir;
1267
				uint32_t index;
1268

1269
				r = git_array_alloc(cfg_file->readers);
1270 1271
				/* The reader may have been reallocated */
				reader = git_array_get(cfg_file->readers, reader_idx);
1272
				memset(r, 0, sizeof(struct reader));
1273 1274 1275
				if ((result = git_path_dirname_r(&path, reader->file_path)) < 0)
					break;

1276 1277
				/* We need to know out index in the array, as the next config_parse call may realloc */
				index = git_array_size(cfg_file->readers) - 1;
1278 1279 1280 1281 1282 1283 1284
				dir = git_buf_detach(&path);
				result = included_path(&path, dir, var->entry->value);
				git__free(dir);

				if (result < 0)
					break;

1285 1286 1287 1288
				r->file_path = git_buf_detach(&path);
				git_buf_init(&r->buffer, 0);
				if ((result = git_futils_readbuffer_updated(&r->buffer, r->file_path, &r->file_mtime,
									    &r->file_size, NULL)) < 0)
1289 1290
					break;

1291
				result = config_parse(values, cfg_file, r, level, depth+1);
1292
				r = git_array_get(cfg_file->readers, index);
1293
				git_buf_free(&r->buffer);
1294 1295 1296 1297 1298

				if (result < 0)
					break;
			}

1299 1300 1301 1302
			break;
		}
	}

1303
	git__free(current_section);
1304
	return result;
1305 1306
}

1307
static int write_section(git_filebuf *file, const char *key)
1308
{
1309
	int result;
1310
	const char *dot;
1311
	git_buf buf = GIT_BUF_INIT;
1312

1313
	/* All of this just for [section "subsection"] */
1314
	dot = strchr(key, '.');
1315
	git_buf_putc(&buf, '[');
1316
	if (dot == NULL) {
1317
		git_buf_puts(&buf, key);
1318
	} else {
1319
		char *escaped;
1320
		git_buf_put(&buf, key, dot - key);
1321 1322 1323 1324
		escaped = escape_value(dot + 1);
		GITERR_CHECK_ALLOC(escaped);
		git_buf_printf(&buf, " \"%s\"", escaped);
		git__free(escaped);
1325 1326
	}
	git_buf_puts(&buf, "]\n");
1327

1328
	if (git_buf_oom(&buf))
1329
		return -1;
1330

1331
	result = git_filebuf_write(file, git_buf_cstr(&buf), buf.size);
1332
	git_buf_free(&buf);
1333

1334
	return result;
1335 1336
}

Vicent Marti committed
1337
static const char *quotes_for_value(const char *value)
1338
{
Vicent Marti committed
1339 1340 1341 1342 1343 1344
	const char *ptr;

	if (value[0] == ' ' || value[0] == '\0')
		return "\"";

	for (ptr = value; *ptr; ++ptr) {
1345
		if (*ptr == ';' || *ptr == '#')
Vicent Marti committed
1346
			return "\"";
1347 1348
	}

Vicent Marti committed
1349 1350 1351 1352
	if (ptr[-1] == ' ')
		return "\"";

	return "";
1353 1354
}

1355 1356 1357
/*
 * This is pretty much the parsing, except we write out anything we don't have
 */
1358
static int config_write(diskfile_backend *cfg, const char *key, const regex_t *preg, const char* value)
1359
{
1360 1361
	int result, c;
	int section_matches = 0, last_section_matched = 0, preg_replaced = 0, write_trailer = 0;
1362
	const char *pre_end = NULL, *post_start = NULL, *data_start, *write_start;
1363
	char *current_section = NULL, *section, *name, *ldot;
1364
	git_filebuf file = GIT_FILEBUF_INIT;
1365
	struct reader *reader = git_array_get(cfg->readers, 0);
1366 1367

	/* We need to read in our own config file */
1368
	result = git_futils_readbuffer(&reader->buffer, cfg->file_path);
1369 1370

	/* Initialise the reading position */
1371
	if (result == GIT_ENOTFOUND) {
1372 1373
		reader->read_ptr = NULL;
		reader->eof = 1;
1374
		data_start = NULL;
1375
		git_buf_clear(&reader->buffer);
1376
	} else if (result == 0) {
1377 1378 1379
		reader->read_ptr = reader->buffer.ptr;
		reader->eof = 0;
		data_start = reader->read_ptr;
1380 1381
	} else {
		return -1; /* OS error when reading the file */
1382
	}
1383

1384 1385
	write_start = data_start;

1386
	/* Lock the file */
nulltoken committed
1387 1388 1389 1390 1391
	if ((result = git_filebuf_open(
		&file, cfg->file_path, 0, GIT_CONFIG_FILE_MODE)) < 0) {
			git_buf_free(&reader->buffer);
			return result;
	}
1392

1393
	skip_bom(reader);
1394 1395 1396
	ldot = strrchr(key, '.');
	name = ldot + 1;
	section = git__strndup(key, ldot - key);
1397

1398 1399
	while (!reader->eof) {
		c = reader_peek(reader, SKIP_WHITESPACE);
1400

1401
		if (c == '\0') { /* We've arrived at the end of the file */
1402 1403
			break;

1404
		} else if (c == '[') { /* section header, new section begins */
1405 1406 1407 1408 1409 1410 1411
			/*
			 * We set both positions to the current one in case we
			 * need to add a variable to the end of a section. In that
			 * case, we want both variables to point just before the
			 * new section. If we actually want to replace it, the
			 * default case will take care of updating them.
			 */
1412
			pre_end = post_start = reader->read_ptr;
1413 1414

			git__free(current_section);
1415
			current_section = NULL;
1416
			if (parse_section_header(reader, &current_section) < 0)
1417
				goto rewrite_fail;
1418 1419 1420

			/* Keep track of when it stops matching */
			last_section_matched = section_matches;
1421
			section_matches = !strcmp(current_section, section);
1422
		}
1423

1424
		else if (c == ';' || c == '#') {
1425
			reader_consume_line(reader);
1426
		}
1427

1428
		else {
1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440
			/*
			 * If the section doesn't match, but the last section did,
			 * it means we need to add a variable (so skip the line
			 * otherwise). If both the section and name match, we need
			 * to overwrite the variable (so skip the line
			 * otherwise). pre_end needs to be updated each time so we
			 * don't loose that information, but we only need to
			 * update post_start if we're going to use it in this
			 * iteration.
			 */
			if (!section_matches) {
				if (!last_section_matched) {
1441
					reader_consume_line(reader);
1442
					continue;
1443 1444
				}
			} else {
1445 1446
				int has_matched = 0;
				char *var_name, *var_value;
1447

1448 1449
				pre_end = reader->read_ptr;
				if (parse_variable(reader, &var_name, &var_value) < 0)
1450
					goto rewrite_fail;
1451

1452 1453 1454
				/* First try to match the name of the variable */
				if (strcasecmp(name, var_name) == 0)
					has_matched = 1;
1455

1456 1457 1458 1459
				/* If the name matches, and we have a regex to match the
				 * value, try to match it */
				if (has_matched && preg != NULL)
					has_matched = (regexec(preg, var_value, 0, NULL, 0) == 0);
1460

1461 1462
				git__free(var_name);
				git__free(var_value);
1463

1464 1465 1466
				/* if there is no match, keep going */
				if (!has_matched)
					continue;
1467

1468
				post_start = reader->read_ptr;
1469 1470
			}

1471 1472
			/* We've found the variable we wanted to change, so
			 * write anything up to it */
1473
			git_filebuf_write(&file, write_start, pre_end - write_start);
1474
			preg_replaced = 1;
1475

1476 1477 1478
			/* Then replace the variable. If the value is NULL, it
			 * means we want to delete it, so don't write anything. */
			if (value != NULL) {
Vicent Marti committed
1479 1480
				const char *q = quotes_for_value(value);
				git_filebuf_printf(&file, "\t%s = %s%s%s\n", name, q, value, q);
1481 1482
			}

1483 1484 1485 1486 1487 1488 1489
			/*
			 * If we have a multivar, we should keep looking for entries,
			 * but only if we're in the right section. Otherwise we'll end up
			 * looping on the edge of a matching and a non-matching section.
			 */
			if (section_matches && preg != NULL) {
				write_start = post_start;
1490 1491 1492
				continue;
			}

1493 1494
			write_trailer = 1;
			break; /* break from the loop */
1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506
		}
	}

	/*
	 * Being here can mean that
	 *
	 * 1) our section is the last one in the file and we're
	 * adding a variable
	 *
	 * 2) we didn't find a section for us so we need to create it
	 * ourselves.
	 *
1507 1508 1509 1510 1511 1512
	 * 3) we're setting a multivar with a regex, which means we
	 * continue to search for matching values
	 *
	 * In the last case, if we've already replaced a value, we
	 * want to write the rest of the file. Otherwise we need to write
	 * out the whole file and then the new variable.
1513
	 */
1514 1515
	if (write_trailer) {
		/* Write out rest of the file */
1516
		git_filebuf_write(&file, post_start, reader->buffer.size - (post_start - data_start));
1517 1518
	} else {
		if (preg_replaced) {
1519
			git_filebuf_printf(&file, "\n%s", write_start);
1520
		} else {
Vicent Marti committed
1521 1522
			const char *q;

1523
			git_filebuf_write(&file, reader->buffer.ptr, reader->buffer.size);
1524

1525 1526 1527
			if (reader->buffer.size > 0 && *(reader->buffer.ptr + reader->buffer.size - 1) != '\n')
				git_filebuf_write(&file, "\n", 1);

1528 1529 1530 1531 1532 1533 1534 1535 1536
			/* And now if we just need to add a variable */
			if (!section_matches && write_section(&file, section) < 0)
				goto rewrite_fail;

			/* Sanity check: if we are here, and value is NULL, that means that somebody
			 * touched the config file after our intial read. We should probably assert()
			 * this, but instead we'll handle it gracefully with an error. */
			if (value == NULL) {
				giterr_set(GITERR_CONFIG,
1537
					"race condition when writing a config file (a cvar has been removed)");
1538 1539
				goto rewrite_fail;
			}
1540

1541
			/* If we are here, there is at least a section line */
Vicent Marti committed
1542 1543
			q = quotes_for_value(value);
			git_filebuf_printf(&file, "\t%s = %s%s%s\n", name, q, value, q);
1544
		}
1545 1546
	}

1547 1548
	git__free(section);
	git__free(current_section);
1549

1550
	/* refresh stats - if this errors, then commit will error too */
1551
	(void)git_filebuf_stats(&reader->file_mtime, &reader->file_size, &file);
1552

1553
	result = git_filebuf_commit(&file);
1554
	git_buf_free(&reader->buffer);
1555

1556
	return result;
1557

1558
rewrite_fail:
1559
	git__free(section);
1560
	git__free(current_section);
1561

1562
	git_filebuf_cleanup(&file);
1563
	git_buf_free(&reader->buffer);
1564
	return -1;
1565 1566
}

1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
static const char *escapes = "ntb\"\\";
static const char *escaped = "\n\t\b\"\\";

/* Escape the values to write them to the file */
static char *escape_value(const char *ptr)
{
	git_buf buf = GIT_BUF_INIT;
	size_t len;
	const char *esc;

	assert(ptr);

	len = strlen(ptr);
1580 1581 1582
	if (!len)
		return git__calloc(1, sizeof(char));

1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602
	git_buf_grow(&buf, len);

	while (*ptr != '\0') {
		if ((esc = strchr(escaped, *ptr)) != NULL) {
			git_buf_putc(&buf, '\\');
			git_buf_putc(&buf, escapes[esc - escaped]);
		} else {
			git_buf_putc(&buf, *ptr);
		}
		ptr++;
	}

	if (git_buf_oom(&buf)) {
		git_buf_free(&buf);
		return NULL;
	}

	return git_buf_detach(&buf);
}

1603 1604
/* '\"' -> '"' etc */
static char *fixup_line(const char *ptr, int quote_count)
1605
{
1606 1607 1608 1609 1610
	char *str = git__malloc(strlen(ptr) + 1);
	char *out = str, *esc;

	if (str == NULL)
		return NULL;
1611

1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640
	while (*ptr != '\0') {
		if (*ptr == '"') {
			quote_count++;
		} else if (*ptr != '\\') {
			*out++ = *ptr;
		} else {
			/* backslash, check the next char */
			ptr++;
			/* if we're at the end, it's a multiline, so keep the backslash */
			if (*ptr == '\0') {
				*out++ = '\\';
				goto out;
			}
			if ((esc = strchr(escapes, *ptr)) != NULL) {
				*out++ = escaped[esc - escapes];
			} else {
				git__free(str);
				giterr_set(GITERR_CONFIG, "Invalid escape at %s", ptr);
				return NULL;
			}
		}
		ptr++;
	}

out:
	*out = '\0';

	return str;
}
1641 1642 1643

static int is_multiline_var(const char *str)
{
1644
	int count = 0;
1645
	const char *end = str + strlen(str);
1646 1647 1648 1649 1650 1651
	while (end > str && end[-1] == '\\') {
		count++;
		end--;
	}

	/* An odd number means last backslash wasn't escaped, so it's multiline */
1652
	return count & 1;
1653 1654
}

1655
static int parse_multiline_variable(struct reader *reader, git_buf *value, int in_quotes)
1656
{
1657 1658
	char *line = NULL, *proc_line = NULL;
	int quote_count;
1659 1660

	/* Check that the next line exists */
1661
	line = reader_readline(reader, false);
1662
	if (line == NULL)
1663
		return -1;
1664 1665 1666

	/* We've reached the end of the file, there is input missing */
	if (line[0] == '\0') {
1667
		set_parse_error(reader, 0, "Unexpected end of file while parsing multine var");
1668 1669
		git__free(line);
		return -1;
1670 1671
	}

1672
	quote_count = strip_comments(line, !!in_quotes);
1673 1674 1675

	/* If it was just a comment, pretend it didn't exist */
	if (line[0] == '\0') {
1676
		git__free(line);
1677
		return parse_multiline_variable(reader, value, quote_count);
1678
		/* TODO: unbounded recursion. This **could** be exploitable */
1679 1680
	}

1681 1682 1683 1684
	/* Drop the continuation character '\': to closely follow the UNIX
	 * standard, this character **has** to be last one in the buf, with
	 * no whitespace after it */
	assert(is_multiline_var(value->ptr));
1685
	git_buf_shorten(value, 1);
1686

1687 1688 1689 1690
	proc_line = fixup_line(line, in_quotes);
	if (proc_line == NULL) {
		git__free(line);
		return -1;
1691
	}
1692
	/* add this line to the multiline var */
1693
	git_buf_puts(value, proc_line);
1694
	git__free(line);
1695
	git__free(proc_line);
1696 1697

	/*
1698 1699
	 * If we need to continue reading the next line, let's just
	 * keep putting stuff in the buffer
1700
	 */
1701
	if (is_multiline_var(value->ptr))
1702
		return parse_multiline_variable(reader, value, quote_count);
1703

1704
	return 0;
1705 1706
}

1707
static int parse_variable(struct reader *reader, char **var_name, char **var_value)
1708 1709 1710 1711
{
	const char *var_end = NULL;
	const char *value_start = NULL;
	char *line;
1712
	int quote_count;
1713

1714
	line = reader_readline(reader, true);
1715
	if (line == NULL)
1716
		return -1;
1717

1718
	quote_count = strip_comments(line, 0);
1719 1720 1721 1722 1723 1724 1725 1726

	var_end = strchr(line, '=');

	if (var_end == NULL)
		var_end = strchr(line, '\0');
	else
		value_start = var_end + 1;

Russell Belfer committed
1727
	do var_end--;
1728
	while (var_end>line && git__isspace(*var_end));
1729

1730 1731
	*var_name = git__strndup(line, var_end - line + 1);
	GITERR_CHECK_ALLOC(*var_name);
1732

1733 1734
	/* If there is no value, boolean true is assumed */
	*var_value = NULL;
1735 1736 1737 1738 1739

	/*
	 * Now, let's try to parse the value
	 */
	if (value_start != NULL) {
1740
		while (git__isspace(value_start[0]))
1741 1742 1743
			value_start++;

		if (is_multiline_var(value_start)) {
1744
			git_buf multi_value = GIT_BUF_INIT;
1745 1746 1747
			char *proc_line = fixup_line(value_start, 0);
			GITERR_CHECK_ALLOC(proc_line);
			git_buf_puts(&multi_value, proc_line);
1748
			git__free(proc_line);
1749
			if (parse_multiline_variable(reader, &multi_value, quote_count) < 0 || git_buf_oom(&multi_value)) {
1750
				git__free(*var_name);
1751 1752 1753
				git__free(line);
				git_buf_free(&multi_value);
				return -1;
1754
			}
1755

1756
			*var_value = git_buf_detach(&multi_value);
1757

1758 1759
		}
		else if (value_start[0] != '\0') {
1760
			*var_value = fixup_line(value_start, 0);
1761
			GITERR_CHECK_ALLOC(*var_value);
1762 1763 1764
		} else { /* equals sign but missing rhs */
			*var_value = git__strdup("");
			GITERR_CHECK_ALLOC(*var_value);
1765 1766 1767
		}
	}

1768
	git__free(line);
1769
	return 0;
1770
}