core.prefersymlinkrefs: use symlinks for .git/HEAD
[git/git.git] / config.c
1 /*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 * Copyright (C) Johannes Schindelin, 2005
6 *
7 */
8 #include "cache.h"
9 #include <regex.h>
10
11 #define MAXNAME (256)
12
13 static FILE *config_file;
14 static const char *config_file_name;
15 static int config_linenr;
16 static int get_next_char(void)
17 {
18 int c;
19 FILE *f;
20
21 c = '\n';
22 if ((f = config_file) != NULL) {
23 c = fgetc(f);
24 if (c == '\r') {
25 /* DOS like systems */
26 c = fgetc(f);
27 if (c != '\n') {
28 ungetc(c, f);
29 c = '\r';
30 }
31 }
32 if (c == '\n')
33 config_linenr++;
34 if (c == EOF) {
35 config_file = NULL;
36 c = '\n';
37 }
38 }
39 return c;
40 }
41
42 static char *parse_value(void)
43 {
44 static char value[1024];
45 int quote = 0, comment = 0, len = 0, space = 0;
46
47 for (;;) {
48 int c = get_next_char();
49 if (len >= sizeof(value))
50 return NULL;
51 if (c == '\n') {
52 if (quote)
53 return NULL;
54 value[len] = 0;
55 return value;
56 }
57 if (comment)
58 continue;
59 if (isspace(c) && !quote) {
60 space = 1;
61 continue;
62 }
63 if (!quote) {
64 if (c == ';' || c == '#') {
65 comment = 1;
66 continue;
67 }
68 }
69 if (space) {
70 if (len)
71 value[len++] = ' ';
72 space = 0;
73 }
74 if (c == '\\') {
75 c = get_next_char();
76 switch (c) {
77 case '\n':
78 continue;
79 case 't':
80 c = '\t';
81 break;
82 case 'b':
83 c = '\b';
84 break;
85 case 'n':
86 c = '\n';
87 break;
88 /* Some characters escape as themselves */
89 case '\\': case '"':
90 break;
91 /* Reject unknown escape sequences */
92 default:
93 return NULL;
94 }
95 value[len++] = c;
96 continue;
97 }
98 if (c == '"') {
99 quote = 1-quote;
100 continue;
101 }
102 value[len++] = c;
103 }
104 }
105
106 static int get_value(config_fn_t fn, char *name, unsigned int len)
107 {
108 int c;
109 char *value;
110
111 /* Get the full name */
112 for (;;) {
113 c = get_next_char();
114 if (c == EOF)
115 break;
116 if (!isalnum(c))
117 break;
118 name[len++] = tolower(c);
119 if (len >= MAXNAME)
120 return -1;
121 }
122 name[len] = 0;
123 while (c == ' ' || c == '\t')
124 c = get_next_char();
125
126 value = NULL;
127 if (c != '\n') {
128 if (c != '=')
129 return -1;
130 value = parse_value();
131 if (!value)
132 return -1;
133 }
134 return fn(name, value);
135 }
136
137 static int get_base_var(char *name)
138 {
139 int baselen = 0;
140
141 for (;;) {
142 int c = get_next_char();
143 if (c == EOF)
144 return -1;
145 if (c == ']')
146 return baselen;
147 if (!isalnum(c) && c != '.')
148 return -1;
149 if (baselen > MAXNAME / 2)
150 return -1;
151 name[baselen++] = tolower(c);
152 }
153 }
154
155 static int git_parse_file(config_fn_t fn)
156 {
157 int comment = 0;
158 int baselen = 0;
159 static char var[MAXNAME];
160
161 for (;;) {
162 int c = get_next_char();
163 if (c == '\n') {
164 /* EOF? */
165 if (!config_file)
166 return 0;
167 comment = 0;
168 continue;
169 }
170 if (comment || isspace(c))
171 continue;
172 if (c == '#' || c == ';') {
173 comment = 1;
174 continue;
175 }
176 if (c == '[') {
177 baselen = get_base_var(var);
178 if (baselen <= 0)
179 break;
180 var[baselen++] = '.';
181 var[baselen] = 0;
182 continue;
183 }
184 if (!isalpha(c))
185 break;
186 var[baselen] = tolower(c);
187 if (get_value(fn, var, baselen+1) < 0)
188 break;
189 }
190 die("bad config file line %d in %s", config_linenr, config_file_name);
191 }
192
193 int git_config_int(const char *name, const char *value)
194 {
195 if (value && *value) {
196 char *end;
197 int val = strtol(value, &end, 0);
198 if (!*end)
199 return val;
200 }
201 die("bad config value for '%s' in %s", name, config_file_name);
202 }
203
204 int git_config_bool(const char *name, const char *value)
205 {
206 if (!value)
207 return 1;
208 if (!*value)
209 return 0;
210 if (!strcasecmp(value, "true"))
211 return 1;
212 if (!strcasecmp(value, "false"))
213 return 0;
214 return git_config_int(name, value) != 0;
215 }
216
217 int git_default_config(const char *var, const char *value)
218 {
219 /* This needs a better name */
220 if (!strcmp(var, "core.filemode")) {
221 trust_executable_bit = git_config_bool(var, value);
222 return 0;
223 }
224
225 if (!strcmp(var, "core.ignorestat")) {
226 assume_unchanged = git_config_bool(var, value);
227 return 0;
228 }
229
230 if (!strcmp(var, "core.prefersymlinkrefs")) {
231 prefer_symlink_refs = git_config_bool(var, value);
232 return 0;
233 }
234
235 if (!strcmp(var, "core.warnambiguousrefs")) {
236 warn_ambiguous_refs = git_config_bool(var, value);
237 return 0;
238 }
239
240 if (!strcmp(var, "user.name")) {
241 strncpy(git_default_name, value, sizeof(git_default_name));
242 return 0;
243 }
244
245 if (!strcmp(var, "user.email")) {
246 strncpy(git_default_email, value, sizeof(git_default_email));
247 return 0;
248 }
249
250 if (!strcmp(var, "i18n.commitencoding")) {
251 strncpy(git_commit_encoding, value, sizeof(git_commit_encoding));
252 return 0;
253 }
254
255 /* Add other config variables here and to Documentation/config.txt. */
256 return 0;
257 }
258
259 int git_config_from_file(config_fn_t fn, const char *filename)
260 {
261 int ret;
262 FILE *f = fopen(filename, "r");
263
264 ret = -1;
265 if (f) {
266 config_file = f;
267 config_file_name = filename;
268 config_linenr = 1;
269 ret = git_parse_file(fn);
270 fclose(f);
271 config_file_name = NULL;
272 }
273 return ret;
274 }
275
276 int git_config(config_fn_t fn)
277 {
278 return git_config_from_file(fn, git_path("config"));
279 }
280
281 /*
282 * Find all the stuff for git_config_set() below.
283 */
284
285 #define MAX_MATCHES 512
286
287 static struct {
288 int baselen;
289 char* key;
290 int do_not_match;
291 regex_t* value_regex;
292 int multi_replace;
293 off_t offset[MAX_MATCHES];
294 enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
295 int seen;
296 } store;
297
298 static int matches(const char* key, const char* value)
299 {
300 return !strcmp(key, store.key) &&
301 (store.value_regex == NULL ||
302 (store.do_not_match ^
303 !regexec(store.value_regex, value, 0, NULL, 0)));
304 }
305
306 static int store_aux(const char* key, const char* value)
307 {
308 switch (store.state) {
309 case KEY_SEEN:
310 if (matches(key, value)) {
311 if (store.seen == 1 && store.multi_replace == 0) {
312 fprintf(stderr,
313 "Warning: %s has multiple values\n",
314 key);
315 } else if (store.seen >= MAX_MATCHES) {
316 fprintf(stderr, "Too many matches\n");
317 return 1;
318 }
319
320 store.offset[store.seen] = ftell(config_file);
321 store.seen++;
322 }
323 break;
324 case SECTION_SEEN:
325 if (strncmp(key, store.key, store.baselen+1)) {
326 store.state = SECTION_END_SEEN;
327 break;
328 } else
329 /* do not increment matches: this is no match */
330 store.offset[store.seen] = ftell(config_file);
331 /* fallthru */
332 case SECTION_END_SEEN:
333 case START:
334 if (matches(key, value)) {
335 store.offset[store.seen] = ftell(config_file);
336 store.state = KEY_SEEN;
337 store.seen++;
338 } else if (strrchr(key, '.') - key == store.baselen &&
339 !strncmp(key, store.key, store.baselen))
340 store.state = SECTION_SEEN;
341 }
342 return 0;
343 }
344
345 static void store_write_section(int fd, const char* key)
346 {
347 write(fd, "[", 1);
348 write(fd, key, store.baselen);
349 write(fd, "]\n", 2);
350 }
351
352 static void store_write_pair(int fd, const char* key, const char* value)
353 {
354 int i;
355
356 write(fd, "\t", 1);
357 write(fd, key+store.baselen+1,
358 strlen(key+store.baselen+1));
359 write(fd, " = ", 3);
360 for (i = 0; value[i]; i++)
361 switch (value[i]) {
362 case '\n': write(fd, "\\n", 2); break;
363 case '\t': write(fd, "\\t", 2); break;
364 case '"': case '\\': write(fd, "\\", 1);
365 default: write(fd, value+i, 1);
366 }
367 write(fd, "\n", 1);
368 }
369
370 static int find_beginning_of_line(const char* contents, int size,
371 int offset_, int* found_bracket)
372 {
373 int equal_offset = size, bracket_offset = size;
374 int offset;
375
376 for (offset = offset_-2; offset > 0
377 && contents[offset] != '\n'; offset--)
378 switch (contents[offset]) {
379 case '=': equal_offset = offset; break;
380 case ']': bracket_offset = offset; break;
381 }
382 if (bracket_offset < equal_offset) {
383 *found_bracket = 1;
384 offset = bracket_offset+1;
385 } else
386 offset++;
387
388 return offset;
389 }
390
391 int git_config_set(const char* key, const char* value)
392 {
393 return git_config_set_multivar(key, value, NULL, 0);
394 }
395
396 /*
397 * If value==NULL, unset in (remove from) config,
398 * if value_regex!=NULL, disregard key/value pairs where value does not match.
399 * if multi_replace==0, nothing, or only one matching key/value is replaced,
400 * else all matching key/values (regardless how many) are removed,
401 * before the new pair is written.
402 *
403 * Returns 0 on success.
404 *
405 * This function does this:
406 *
407 * - it locks the config file by creating ".git/config.lock"
408 *
409 * - it then parses the config using store_aux() as validator to find
410 * the position on the key/value pair to replace. If it is to be unset,
411 * it must be found exactly once.
412 *
413 * - the config file is mmap()ed and the part before the match (if any) is
414 * written to the lock file, then the changed part and the rest.
415 *
416 * - the config file is removed and the lock file rename()d to it.
417 *
418 */
419 int git_config_set_multivar(const char* key, const char* value,
420 const char* value_regex, int multi_replace)
421 {
422 int i;
423 int fd, in_fd;
424 int ret;
425 char* config_filename = strdup(git_path("config"));
426 char* lock_file = strdup(git_path("config.lock"));
427 const char* last_dot = strrchr(key, '.');
428
429 /*
430 * Since "key" actually contains the section name and the real
431 * key name separated by a dot, we have to know where the dot is.
432 */
433
434 if (last_dot == NULL) {
435 fprintf(stderr, "key does not contain a section: %s\n", key);
436 ret = 2;
437 goto out_free;
438 }
439 store.baselen = last_dot - key;
440
441 store.multi_replace = multi_replace;
442
443 /*
444 * Validate the key and while at it, lower case it for matching.
445 */
446 store.key = (char*)malloc(strlen(key)+1);
447 for (i = 0; key[i]; i++)
448 if (i != store.baselen &&
449 ((!isalnum(key[i]) && key[i] != '.') ||
450 (i == store.baselen+1 && !isalpha(key[i])))) {
451 fprintf(stderr, "invalid key: %s\n", key);
452 free(store.key);
453 ret = 1;
454 goto out_free;
455 } else
456 store.key[i] = tolower(key[i]);
457 store.key[i] = 0;
458
459 /*
460 * The lock_file serves a purpose in addition to locking: the new
461 * contents of .git/config will be written into it.
462 */
463 fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
464 if (fd < 0) {
465 fprintf(stderr, "could not lock config file\n");
466 free(store.key);
467 ret = -1;
468 goto out_free;
469 }
470
471 /*
472 * If .git/config does not exist yet, write a minimal version.
473 */
474 in_fd = open(config_filename, O_RDONLY);
475 if ( in_fd < 0 ) {
476 free(store.key);
477
478 if ( ENOENT != errno ) {
479 error("opening %s: %s", config_filename,
480 strerror(errno));
481 close(fd);
482 unlink(lock_file);
483 ret = 3; /* same as "invalid config file" */
484 goto out_free;
485 }
486 /* if nothing to unset, error out */
487 if (value == NULL) {
488 close(fd);
489 unlink(lock_file);
490 ret = 5;
491 goto out_free;
492 }
493
494 store.key = (char*)key;
495 store_write_section(fd, key);
496 store_write_pair(fd, key, value);
497 } else{
498 struct stat st;
499 char* contents;
500 int i, copy_begin, copy_end, new_line = 0;
501
502 if (value_regex == NULL)
503 store.value_regex = NULL;
504 else {
505 if (value_regex[0] == '!') {
506 store.do_not_match = 1;
507 value_regex++;
508 } else
509 store.do_not_match = 0;
510
511 store.value_regex = (regex_t*)malloc(sizeof(regex_t));
512 if (regcomp(store.value_regex, value_regex,
513 REG_EXTENDED)) {
514 fprintf(stderr, "Invalid pattern: %s\n",
515 value_regex);
516 free(store.value_regex);
517 ret = 6;
518 goto out_free;
519 }
520 }
521
522 store.offset[0] = 0;
523 store.state = START;
524 store.seen = 0;
525
526 /*
527 * After this, store.offset will contain the *end* offset
528 * of the last match, or remain at 0 if no match was found.
529 * As a side effect, we make sure to transform only a valid
530 * existing config file.
531 */
532 if (git_config(store_aux)) {
533 fprintf(stderr, "invalid config file\n");
534 free(store.key);
535 if (store.value_regex != NULL) {
536 regfree(store.value_regex);
537 free(store.value_regex);
538 }
539 ret = 3;
540 goto out_free;
541 }
542
543 free(store.key);
544 if (store.value_regex != NULL) {
545 regfree(store.value_regex);
546 free(store.value_regex);
547 }
548
549 /* if nothing to unset, or too many matches, error out */
550 if ((store.seen == 0 && value == NULL) ||
551 (store.seen > 1 && multi_replace == 0)) {
552 close(fd);
553 unlink(lock_file);
554 ret = 5;
555 goto out_free;
556 }
557
558 fstat(in_fd, &st);
559 contents = mmap(NULL, st.st_size, PROT_READ,
560 MAP_PRIVATE, in_fd, 0);
561 close(in_fd);
562
563 if (store.seen == 0)
564 store.seen = 1;
565
566 for (i = 0, copy_begin = 0; i < store.seen; i++) {
567 if (store.offset[i] == 0) {
568 store.offset[i] = copy_end = st.st_size;
569 } else if (store.state != KEY_SEEN) {
570 copy_end = store.offset[i];
571 } else
572 copy_end = find_beginning_of_line(
573 contents, st.st_size,
574 store.offset[i]-2, &new_line);
575
576 /* write the first part of the config */
577 if (copy_end > copy_begin) {
578 write(fd, contents + copy_begin,
579 copy_end - copy_begin);
580 if (new_line)
581 write(fd, "\n", 1);
582 }
583 copy_begin = store.offset[i];
584 }
585
586 /* write the pair (value == NULL means unset) */
587 if (value != NULL) {
588 if (store.state == START)
589 store_write_section(fd, key);
590 store_write_pair(fd, key, value);
591 }
592
593 /* write the rest of the config */
594 if (copy_begin < st.st_size)
595 write(fd, contents + copy_begin,
596 st.st_size - copy_begin);
597
598 munmap(contents, st.st_size);
599 unlink(config_filename);
600 }
601
602 close(fd);
603
604 if (rename(lock_file, config_filename) < 0) {
605 fprintf(stderr, "Could not rename the lock file?\n");
606 ret = 4;
607 goto out_free;
608 }
609
610 ret = 0;
611
612 out_free:
613 if (config_filename)
614 free(config_filename);
615 if (lock_file)
616 free(lock_file);
617 return ret;
618 }
619
620