summaryrefslogtreecommitdiff
path: root/config.c
blob: 4e1f0c22862b8c8605dbbf3a83ec4e87d9059513 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
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
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
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
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 * Copyright (C) Johannes Schindelin, 2005
 *
 */
#include "cache.h"
#include <regex.h>

#define MAXNAME (256)

static FILE *config_file;
static const char *config_file_name;
static int config_linenr;
static int get_next_char(void)
{
	int c;
	FILE *f;

	c = '\n';
	if ((f = config_file) != NULL) {
		c = fgetc(f);
		if (c == '\r') {
			/* DOS like systems */
			c = fgetc(f);
			if (c != '\n') {
				ungetc(c, f);
				c = '\r';
			}
		}
		if (c == '\n')
			config_linenr++;
		if (c == EOF) {
			config_file = NULL;
			c = '\n';
		}
	}
	return c;
}

static char *parse_value(void)
{
	static char value[1024];
	int quote = 0, comment = 0, len = 0, space = 0;

	for (;;) {
		int c = get_next_char();
		if (len >= sizeof(value))
			return NULL;
		if (c == '\n') {
			if (quote)
				return NULL;
			value[len] = 0;
			return value;
		}
		if (comment)
			continue;
		if (isspace(c) && !quote) {
			space = 1;
			continue;
		}
		if (space) {
			if (len)
				value[len++] = ' ';
			space = 0;
		}
		if (c == '\\') {
			c = get_next_char();
			switch (c) {
			case '\n':
				continue;
			case 't':
				c = '\t';
				break;
			case 'b':
				c = '\b';
				break;
			case 'n':
				c = '\n';
				break;
			/* Some characters escape as themselves */
			case '\\': case '"':
				break;
			/* Reject unknown escape sequences */
			default:
				return NULL;
			}
			value[len++] = c;
			continue;
		}
		if (c == '"') {
			quote = 1-quote;
			continue;
		}
		if (!quote) {
			if (c == ';' || c == '#') {
				comment = 1;
				continue;
			}
		}
		value[len++] = c;
	}
}

static int get_value(config_fn_t fn, char *name, unsigned int len)
{
	int c;
	char *value;

	/* Get the full name */
	for (;;) {
		c = get_next_char();
		if (c == EOF)
			break;
		if (!isalnum(c))
			break;
		name[len++] = tolower(c);
		if (len >= MAXNAME)
			return -1;
	}
	name[len] = 0;
	while (c == ' ' || c == '\t')
		c = get_next_char();

	value = NULL;
	if (c != '\n') {
		if (c != '=')
			return -1;
		value = parse_value();
		if (!value)
			return -1;
	}
	return fn(name, value);
}

static int get_base_var(char *name)
{
	int baselen = 0;

	for (;;) {
		int c = get_next_char();
		if (c == EOF)
			return -1;
		if (c == ']')
			return baselen;
		if (!isalnum(c) && c != '.')
			return -1;
		if (baselen > MAXNAME / 2)
			return -1;
		name[baselen++] = tolower(c);
	}
}

static int git_parse_file(config_fn_t fn)
{
	int comment = 0;
	int baselen = 0;
	static char var[MAXNAME];

	for (;;) {
		int c = get_next_char();
		if (c == '\n') {
			/* EOF? */
			if (!config_file)
				return 0;
			comment = 0;
			continue;
		}
		if (comment || isspace(c))
			continue;
		if (c == '#' || c == ';') {
			comment = 1;
			continue;
		}
		if (c == '[') {
			baselen = get_base_var(var);
			if (baselen <= 0)
				break;
			var[baselen++] = '.';
			var[baselen] = 0;
			continue;
		}
		if (!isalpha(c))
			break;
		var[baselen] = tolower(c);
		if (get_value(fn, var, baselen+1) < 0)
			break;
	}
	die("bad config file line %d in %s", config_linenr, config_file_name);
}

int git_config_int(const char *name, const char *value)
{
	if (value && *value) {
		char *end;
		int val = strtol(value, &end, 0);
		if (!*end)
			return val;
	}
	die("bad config value for '%s' in %s", name, config_file_name);
}

int git_config_bool(const char *name, const char *value)
{
	if (!value)
		return 1;
	if (!*value)
		return 0;
	if (!strcasecmp(value, "true"))
		return 1;
	if (!strcasecmp(value, "false"))
		return 0;
	return git_config_int(name, value) != 0;
}

int git_default_config(const char *var, const char *value)
{
	/* This needs a better name */
	if (!strcmp(var, "core.filemode")) {
		trust_executable_bit = git_config_bool(var, value);
		return 0;
	}

	if (!strcmp(var, "core.ignorestat")) {
		assume_unchanged = git_config_bool(var, value);
		return 0;
	}

	if (!strcmp(var, "core.symrefsonly")) {
		only_use_symrefs = git_config_bool(var, value);
		return 0;
	}

	if (!strcmp(var, "core.warnambiguousrefs")) {
		warn_ambiguous_refs = git_config_bool(var, value);
		return 0;
	}

	if (!strcmp(var, "user.name")) {
		strncpy(git_default_name, value, sizeof(git_default_name));
		return 0;
	}

	if (!strcmp(var, "user.email")) {
		strncpy(git_default_email, value, sizeof(git_default_email));
		return 0;
	}

	if (!strcmp(var, "i18n.commitencoding")) {
		strncpy(git_commit_encoding, value, sizeof(git_commit_encoding));
		return 0;
	}

	/* Add other config variables here and to Documentation/config.txt. */
	return 0;
}

int git_config_from_file(config_fn_t fn, const char *filename)
{
	int ret;
	FILE *f = fopen(filename, "r");

	ret = -1;
	if (f) {
		config_file = f;
		config_file_name = filename;
		config_linenr = 1;
		ret = git_parse_file(fn);
		fclose(f);
		config_file_name = NULL;
	}
	return ret;
}

int git_config(config_fn_t fn)
{
	return git_config_from_file(fn, git_path("config"));
}

/*
 * Find all the stuff for git_config_set() below.
 */

#define MAX_MATCHES 512

static struct {
	int baselen;
	char* key;
	int do_not_match;
	regex_t* value_regex;
	int multi_replace;
	off_t offset[MAX_MATCHES];
	enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
	int seen;
} store;

static int matches(const char* key, const char* value)
{
	return !strcmp(key, store.key) &&
		(store.value_regex == NULL ||
		 (store.do_not_match ^
		  !regexec(store.value_regex, value, 0, NULL, 0)));
}

static int store_aux(const char* key, const char* value)
{
	switch (store.state) {
	case KEY_SEEN:
		if (matches(key, value)) {
			if (store.seen == 1 && store.multi_replace == 0) {
				fprintf(stderr,
					"Warning: %s has multiple values\n",
					key);
			} else if (store.seen >= MAX_MATCHES) {
				fprintf(stderr, "Too many matches\n");
				return 1;
			}

			store.offset[store.seen] = ftell(config_file);
			store.seen++;
		}
		break;
	case SECTION_SEEN:
		if (strncmp(key, store.key, store.baselen+1)) {
			store.state = SECTION_END_SEEN;
			break;
		} else
			/* do not increment matches: this is no match */
			store.offset[store.seen] = ftell(config_file);
		/* fallthru */
	case SECTION_END_SEEN:
	case START:
		if (matches(key, value)) {
			store.offset[store.seen] = ftell(config_file);
			store.state = KEY_SEEN;
			store.seen++;
		} else if(!strncmp(key, store.key, store.baselen))
			store.state = SECTION_SEEN;
	}
	return 0;
}

static void store_write_section(int fd, const char* key)
{
	write(fd, "[", 1);
	write(fd, key, store.baselen);
	write(fd, "]\n", 2);
}

static void store_write_pair(int fd, const char* key, const char* value)
{
	int i;

	write(fd, "\t", 1);
	write(fd, key+store.baselen+1,
		strlen(key+store.baselen+1));
	write(fd, " = ", 3);
	for (i = 0; value[i]; i++)
		switch (value[i]) {
		case '\n': write(fd, "\\n", 2); break;
		case '\t': write(fd, "\\t", 2); break;
		case '"': case '\\': write(fd, "\\", 1);
		default: write(fd, value+i, 1);
	}
	write(fd, "\n", 1);
}

static int find_beginning_of_line(const char* contents, int size,
	int offset_, int* found_bracket)
{
	int equal_offset = size, bracket_offset = size;
	int offset;

	for (offset = offset_-2; offset > 0 
			&& contents[offset] != '\n'; offset--)
		switch (contents[offset]) {
			case '=': equal_offset = offset; break;
			case ']': bracket_offset = offset; break;
		}
	if (bracket_offset < equal_offset) {
		*found_bracket = 1;
		offset = bracket_offset+1;
	} else
		offset++;

	return offset;
}

int git_config_set(const char* key, const char* value)
{
	return git_config_set_multivar(key, value, NULL, 0);
}

/*
 * If value==NULL, unset in (remove from) config,
 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 *     else all matching key/values (regardless how many) are removed,
 *     before the new pair is written.
 *
 * Returns 0 on success.
 *
 * This function does this:
 *
 * - it locks the config file by creating ".git/config.lock"
 *
 * - it then parses the config using store_aux() as validator to find
 *   the position on the key/value pair to replace. If it is to be unset,
 *   it must be found exactly once.
 *
 * - the config file is mmap()ed and the part before the match (if any) is
 *   written to the lock file, then the changed part and the rest.
 *
 * - the config file is removed and the lock file rename()d to it.
 *
 */
int git_config_set_multivar(const char* key, const char* value,
	const char* value_regex, int multi_replace)
{
	int i;
	int fd, in_fd;
	int ret;
	char* config_filename = strdup(git_path("config"));
	char* lock_file = strdup(git_path("config.lock"));
	const char* last_dot = strrchr(key, '.');

	/*
	 * Since "key" actually contains the section name and the real
	 * key name separated by a dot, we have to know where the dot is.
	 */

	if (last_dot == NULL) {
		fprintf(stderr, "key does not contain a section: %s\n", key);
		ret = 2;
		goto out_free;
	}
	store.baselen = last_dot - key;

	store.multi_replace = multi_replace;

	/*
	 * Validate the key and while at it, lower case it for matching.
	 */
	store.key = (char*)malloc(strlen(key)+1);
	for (i = 0; key[i]; i++)
		if (i != store.baselen &&
				((!isalnum(key[i]) && key[i] != '.') ||
				 (i == store.baselen+1 && !isalpha(key[i])))) {
			fprintf(stderr, "invalid key: %s\n", key);
			free(store.key);
			ret = 1;
			goto out_free;
		} else
			store.key[i] = tolower(key[i]);
	store.key[i] = 0;

	/*
	 * The lock_file serves a purpose in addition to locking: the new
	 * contents of .git/config will be written into it.
	 */
	fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
	if (fd < 0) {
		fprintf(stderr, "could not lock config file\n");
		free(store.key);
		ret = -1;
		goto out_free;
	}

	/*
	 * If .git/config does not exist yet, write a minimal version.
	 */
	in_fd = open(config_filename, O_RDONLY);
	if ( in_fd < 0 ) {
		free(store.key);

		if ( ENOENT != errno ) {
			error("opening %s: %s", config_filename,
			      strerror(errno));
			close(fd);
			unlink(lock_file);
			ret = 3; /* same as "invalid config file" */
			goto out_free;
		}
		/* if nothing to unset, error out */
		if (value == NULL) {
			close(fd);
			unlink(lock_file);
			ret = 5;
			goto out_free;
		}

		store.key = (char*)key;
		store_write_section(fd, key);
		store_write_pair(fd, key, value);
	} else{
		struct stat st;
		char* contents;
		int i, copy_begin, copy_end, new_line = 0;

		if (value_regex == NULL)
			store.value_regex = NULL;
		else {
			if (value_regex[0] == '!') {
				store.do_not_match = 1;
				value_regex++;
			} else
				store.do_not_match = 0;

			store.value_regex = (regex_t*)malloc(sizeof(regex_t));
			if (regcomp(store.value_regex, value_regex,
					REG_EXTENDED)) {
				fprintf(stderr, "Invalid pattern: %s\n",
					value_regex);
				free(store.value_regex);
				ret = 6;
				goto out_free;
			}
		}

		store.offset[0] = 0;
		store.state = START;
		store.seen = 0;

		/*
		 * After this, store.offset will contain the *end* offset
		 * of the last match, or remain at 0 if no match was found.
		 * As a side effect, we make sure to transform only a valid
		 * existing config file.
		 */
		if (git_config(store_aux)) {
			fprintf(stderr, "invalid config file\n");
			free(store.key);
			if (store.value_regex != NULL) {
				regfree(store.value_regex);
				free(store.value_regex);
			}
			ret = 3;
			goto out_free;
		}

		free(store.key);
		if (store.value_regex != NULL) {
			regfree(store.value_regex);
			free(store.value_regex);
		}

		/* if nothing to unset, or too many matches, error out */
		if ((store.seen == 0 && value == NULL) ||
				(store.seen > 1 && multi_replace == 0)) {
			close(fd);
			unlink(lock_file);
			ret = 5;
			goto out_free;
		}

		fstat(in_fd, &st);
		contents = mmap(NULL, st.st_size, PROT_READ,
			MAP_PRIVATE, in_fd, 0);
		close(in_fd);

		if (store.seen == 0)
			store.seen = 1;

		for (i = 0, copy_begin = 0; i < store.seen; i++) {
			if (store.offset[i] == 0) {
				store.offset[i] = copy_end = st.st_size;
			} else if (store.state != KEY_SEEN) {
				copy_end = store.offset[i];
			} else
				copy_end = find_beginning_of_line(
					contents, st.st_size,
					store.offset[i]-2, &new_line);

			/* write the first part of the config */
			if (copy_end > copy_begin) {
				write(fd, contents + copy_begin,
				copy_end - copy_begin);
				if (new_line)
					write(fd, "\n", 1);
			}
			copy_begin = store.offset[i];
		}

		/* write the pair (value == NULL means unset) */
		if (value != NULL) {
			if (store.state == START)
				store_write_section(fd, key);
			store_write_pair(fd, key, value);
		}

		/* write the rest of the config */
		if (copy_begin < st.st_size)
			write(fd, contents + copy_begin,
				st.st_size - copy_begin);

		munmap(contents, st.st_size);
		unlink(config_filename);
	}

	close(fd);

	if (rename(lock_file, config_filename) < 0) {
		fprintf(stderr, "Could not rename the lock file?\n");
		ret = 4;
		goto out_free;
	}

	ret = 0;

out_free:
	if (config_filename)
		free(config_filename);
	if (lock_file)
		free(lock_file);
	return ret;
}