Merge branch 'maint'
[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
10 #define MAXNAME (256)
11
12 static FILE *config_file;
13 static const char *config_file_name;
14 static int config_linenr;
15 static int zlib_compression_seen;
16
17 static int get_next_char(void)
18 {
19         int c;
20         FILE *f;
21
22         c = '\n';
23         if ((f = config_file) != NULL) {
24                 c = fgetc(f);
25                 if (c == '\r') {
26                         /* DOS like systems */
27                         c = fgetc(f);
28                         if (c != '\n') {
29                                 ungetc(c, f);
30                                 c = '\r';
31                         }
32                 }
33                 if (c == '\n')
34                         config_linenr++;
35                 if (c == EOF) {
36                         config_file = NULL;
37                         c = '\n';
38                 }
39         }
40         return c;
41 }
42
43 static char *parse_value(void)
44 {
45         static char value[1024];
46         int quote = 0, comment = 0, len = 0, space = 0;
47
48         for (;;) {
49                 int c = get_next_char();
50                 if (len >= sizeof(value))
51                         return NULL;
52                 if (c == '\n') {
53                         if (quote)
54                                 return NULL;
55                         value[len] = 0;
56                         return value;
57                 }
58                 if (comment)
59                         continue;
60                 if (isspace(c) && !quote) {
61                         space = 1;
62                         continue;
63                 }
64                 if (!quote) {
65                         if (c == ';' || c == '#') {
66                                 comment = 1;
67                                 continue;
68                         }
69                 }
70                 if (space) {
71                         if (len)
72                                 value[len++] = ' ';
73                         space = 0;
74                 }
75                 if (c == '\\') {
76                         c = get_next_char();
77                         switch (c) {
78                         case '\n':
79                                 continue;
80                         case 't':
81                                 c = '\t';
82                                 break;
83                         case 'b':
84                                 c = '\b';
85                                 break;
86                         case 'n':
87                                 c = '\n';
88                                 break;
89                         /* Some characters escape as themselves */
90                         case '\\': case '"':
91                                 break;
92                         /* Reject unknown escape sequences */
93                         default:
94                                 return NULL;
95                         }
96                         value[len++] = c;
97                         continue;
98                 }
99                 if (c == '"') {
100                         quote = 1-quote;
101                         continue;
102                 }
103                 value[len++] = c;
104         }
105 }
106
107 static inline int iskeychar(int c)
108 {
109         return isalnum(c) || c == '-';
110 }
111
112 static int get_value(config_fn_t fn, char *name, unsigned int len)
113 {
114         int c;
115         char *value;
116
117         /* Get the full name */
118         for (;;) {
119                 c = get_next_char();
120                 if (c == EOF)
121                         break;
122                 if (!iskeychar(c))
123                         break;
124                 name[len++] = tolower(c);
125                 if (len >= MAXNAME)
126                         return -1;
127         }
128         name[len] = 0;
129         while (c == ' ' || c == '\t')
130                 c = get_next_char();
131
132         value = NULL;
133         if (c != '\n') {
134                 if (c != '=')
135                         return -1;
136                 value = parse_value();
137                 if (!value)
138                         return -1;
139         }
140         return fn(name, value);
141 }
142
143 static int get_extended_base_var(char *name, int baselen, int c)
144 {
145         do {
146                 if (c == '\n')
147                         return -1;
148                 c = get_next_char();
149         } while (isspace(c));
150
151         /* We require the format to be '[base "extension"]' */
152         if (c != '"')
153                 return -1;
154         name[baselen++] = '.';
155
156         for (;;) {
157                 int c = get_next_char();
158                 if (c == '\n')
159                         return -1;
160                 if (c == '"')
161                         break;
162                 if (c == '\\') {
163                         c = get_next_char();
164                         if (c == '\n')
165                                 return -1;
166                 }
167                 name[baselen++] = c;
168                 if (baselen > MAXNAME / 2)
169                         return -1;
170         }
171
172         /* Final ']' */
173         if (get_next_char() != ']')
174                 return -1;
175         return baselen;
176 }
177
178 static int get_base_var(char *name)
179 {
180         int baselen = 0;
181
182         for (;;) {
183                 int c = get_next_char();
184                 if (c == EOF)
185                         return -1;
186                 if (c == ']')
187                         return baselen;
188                 if (isspace(c))
189                         return get_extended_base_var(name, baselen, c);
190                 if (!iskeychar(c) && c != '.')
191                         return -1;
192                 if (baselen > MAXNAME / 2)
193                         return -1;
194                 name[baselen++] = tolower(c);
195         }
196 }
197
198 static int git_parse_file(config_fn_t fn)
199 {
200         int comment = 0;
201         int baselen = 0;
202         static char var[MAXNAME];
203
204         for (;;) {
205                 int c = get_next_char();
206                 if (c == '\n') {
207                         /* EOF? */
208                         if (!config_file)
209                                 return 0;
210                         comment = 0;
211                         continue;
212                 }
213                 if (comment || isspace(c))
214                         continue;
215                 if (c == '#' || c == ';') {
216                         comment = 1;
217                         continue;
218                 }
219                 if (c == '[') {
220                         baselen = get_base_var(var);
221                         if (baselen <= 0)
222                                 break;
223                         var[baselen++] = '.';
224                         var[baselen] = 0;
225                         continue;
226                 }
227                 if (!isalpha(c))
228                         break;
229                 var[baselen] = tolower(c);
230                 if (get_value(fn, var, baselen+1) < 0)
231                         break;
232         }
233         die("bad config file line %d in %s", config_linenr, config_file_name);
234 }
235
236 int git_config_int(const char *name, const char *value)
237 {
238         if (value && *value) {
239                 char *end;
240                 int val = strtol(value, &end, 0);
241                 if (!*end)
242                         return val;
243                 if (!strcasecmp(end, "k"))
244                         return val * 1024;
245                 if (!strcasecmp(end, "m"))
246                         return val * 1024 * 1024;
247                 if (!strcasecmp(end, "g"))
248                         return val * 1024 * 1024 * 1024;
249         }
250         die("bad config value for '%s' in %s", name, config_file_name);
251 }
252
253 int git_config_bool(const char *name, const char *value)
254 {
255         if (!value)
256                 return 1;
257         if (!*value)
258                 return 0;
259         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
260                 return 1;
261         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
262                 return 0;
263         return git_config_int(name, value) != 0;
264 }
265
266 int git_default_config(const char *var, const char *value)
267 {
268         /* This needs a better name */
269         if (!strcmp(var, "core.filemode")) {
270                 trust_executable_bit = git_config_bool(var, value);
271                 return 0;
272         }
273
274         if (!strcmp(var, "core.symlinks")) {
275                 has_symlinks = git_config_bool(var, value);
276                 return 0;
277         }
278
279         if (!strcmp(var, "core.bare")) {
280                 is_bare_repository_cfg = git_config_bool(var, value);
281                 return 0;
282         }
283
284         if (!strcmp(var, "core.ignorestat")) {
285                 assume_unchanged = git_config_bool(var, value);
286                 return 0;
287         }
288
289         if (!strcmp(var, "core.prefersymlinkrefs")) {
290                 prefer_symlink_refs = git_config_bool(var, value);
291                 return 0;
292         }
293
294         if (!strcmp(var, "core.logallrefupdates")) {
295                 log_all_ref_updates = git_config_bool(var, value);
296                 return 0;
297         }
298
299         if (!strcmp(var, "core.warnambiguousrefs")) {
300                 warn_ambiguous_refs = git_config_bool(var, value);
301                 return 0;
302         }
303
304         if (!strcmp(var, "core.loosecompression")) {
305                 int level = git_config_int(var, value);
306                 if (level == -1)
307                         level = Z_DEFAULT_COMPRESSION;
308                 else if (level < 0 || level > Z_BEST_COMPRESSION)
309                         die("bad zlib compression level %d", level);
310                 zlib_compression_level = level;
311                 zlib_compression_seen = 1;
312                 return 0;
313         }
314
315         if (!strcmp(var, "core.compression")) {
316                 int level = git_config_int(var, value);
317                 if (level == -1)
318                         level = Z_DEFAULT_COMPRESSION;
319                 else if (level < 0 || level > Z_BEST_COMPRESSION)
320                         die("bad zlib compression level %d", level);
321                 core_compression_level = level;
322                 core_compression_seen = 1;
323                 if (!zlib_compression_seen)
324                         zlib_compression_level = level;
325                 return 0;
326         }
327
328         if (!strcmp(var, "core.packedgitwindowsize")) {
329                 int pgsz_x2 = getpagesize() * 2;
330                 packed_git_window_size = git_config_int(var, value);
331
332                 /* This value must be multiple of (pagesize * 2) */
333                 packed_git_window_size /= pgsz_x2;
334                 if (packed_git_window_size < 1)
335                         packed_git_window_size = 1;
336                 packed_git_window_size *= pgsz_x2;
337                 return 0;
338         }
339
340         if (!strcmp(var, "core.packedgitlimit")) {
341                 packed_git_limit = git_config_int(var, value);
342                 return 0;
343         }
344
345         if (!strcmp(var, "core.deltabasecachelimit")) {
346                 delta_base_cache_limit = git_config_int(var, value);
347                 return 0;
348         }
349
350         if (!strcmp(var, "core.autocrlf")) {
351                 if (value && !strcasecmp(value, "input")) {
352                         auto_crlf = -1;
353                         return 0;
354                 }
355                 auto_crlf = git_config_bool(var, value);
356                 return 0;
357         }
358
359         if (!strcmp(var, "user.name")) {
360                 strlcpy(git_default_name, value, sizeof(git_default_name));
361                 return 0;
362         }
363
364         if (!strcmp(var, "user.email")) {
365                 strlcpy(git_default_email, value, sizeof(git_default_email));
366                 return 0;
367         }
368
369         if (!strcmp(var, "i18n.commitencoding")) {
370                 git_commit_encoding = xstrdup(value);
371                 return 0;
372         }
373
374         if (!strcmp(var, "i18n.logoutputencoding")) {
375                 git_log_output_encoding = xstrdup(value);
376                 return 0;
377         }
378
379
380         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
381                 pager_use_color = git_config_bool(var,value);
382                 return 0;
383         }
384
385         /* Add other config variables here and to Documentation/config.txt. */
386         return 0;
387 }
388
389 int git_config_from_file(config_fn_t fn, const char *filename)
390 {
391         int ret;
392         FILE *f = fopen(filename, "r");
393
394         ret = -1;
395         if (f) {
396                 config_file = f;
397                 config_file_name = filename;
398                 config_linenr = 1;
399                 ret = git_parse_file(fn);
400                 fclose(f);
401                 config_file_name = NULL;
402         }
403         return ret;
404 }
405
406 int git_config(config_fn_t fn)
407 {
408         int ret = 0;
409         char *repo_config = NULL;
410         const char *home = NULL, *filename;
411
412         /* $GIT_CONFIG makes git read _only_ the given config file,
413          * $GIT_CONFIG_LOCAL will make it process it in addition to the
414          * global config file, the same way it would the per-repository
415          * config file otherwise. */
416         filename = getenv(CONFIG_ENVIRONMENT);
417         if (!filename) {
418                 if (!access(ETC_GITCONFIG, R_OK))
419                         ret += git_config_from_file(fn, ETC_GITCONFIG);
420                 home = getenv("HOME");
421                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
422                 if (!filename)
423                         filename = repo_config = xstrdup(git_path("config"));
424         }
425
426         if (home) {
427                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
428                 if (!access(user_config, R_OK))
429                         ret = git_config_from_file(fn, user_config);
430                 free(user_config);
431         }
432
433         ret += git_config_from_file(fn, filename);
434         free(repo_config);
435         return ret;
436 }
437
438 /*
439  * Find all the stuff for git_config_set() below.
440  */
441
442 #define MAX_MATCHES 512
443
444 static struct {
445         int baselen;
446         char* key;
447         int do_not_match;
448         regex_t* value_regex;
449         int multi_replace;
450         size_t offset[MAX_MATCHES];
451         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
452         int seen;
453 } store;
454
455 static int matches(const char* key, const char* value)
456 {
457         return !strcmp(key, store.key) &&
458                 (store.value_regex == NULL ||
459                  (store.do_not_match ^
460                   !regexec(store.value_regex, value, 0, NULL, 0)));
461 }
462
463 static int store_aux(const char* key, const char* value)
464 {
465         const char *ep;
466         size_t section_len;
467
468         switch (store.state) {
469         case KEY_SEEN:
470                 if (matches(key, value)) {
471                         if (store.seen == 1 && store.multi_replace == 0) {
472                                 fprintf(stderr,
473                                         "Warning: %s has multiple values\n",
474                                         key);
475                         } else if (store.seen >= MAX_MATCHES) {
476                                 fprintf(stderr, "Too many matches\n");
477                                 return 1;
478                         }
479
480                         store.offset[store.seen] = ftell(config_file);
481                         store.seen++;
482                 }
483                 break;
484         case SECTION_SEEN:
485                 /*
486                  * What we are looking for is in store.key (both
487                  * section and var), and its section part is baselen
488                  * long.  We found key (again, both section and var).
489                  * We would want to know if this key is in the same
490                  * section as what we are looking for.  We already
491                  * know we are in the same section as what should
492                  * hold store.key.
493                  */
494                 ep = strrchr(key, '.');
495                 section_len = ep - key;
496
497                 if ((section_len != store.baselen) ||
498                     memcmp(key, store.key, section_len+1)) {
499                         store.state = SECTION_END_SEEN;
500                         break;
501                 }
502
503                 /*
504                  * Do not increment matches: this is no match, but we
505                  * just made sure we are in the desired section.
506                  */
507                 store.offset[store.seen] = ftell(config_file);
508                 /* fallthru */
509         case SECTION_END_SEEN:
510         case START:
511                 if (matches(key, value)) {
512                         store.offset[store.seen] = ftell(config_file);
513                         store.state = KEY_SEEN;
514                         store.seen++;
515                 } else {
516                         if (strrchr(key, '.') - key == store.baselen &&
517                               !strncmp(key, store.key, store.baselen)) {
518                                         store.state = SECTION_SEEN;
519                                         store.offset[store.seen] = ftell(config_file);
520                         }
521                 }
522         }
523         return 0;
524 }
525
526 static int write_error()
527 {
528         fprintf(stderr, "Failed to write new configuration file\n");
529
530         /* Same error code as "failed to rename". */
531         return 4;
532 }
533
534 static int store_write_section(int fd, const char* key)
535 {
536         const char *dot = strchr(key, '.');
537         int len1 = store.baselen, len2 = -1;
538
539         dot = strchr(key, '.');
540         if (dot) {
541                 int dotlen = dot - key;
542                 if (dotlen < len1) {
543                         len2 = len1 - dotlen - 1;
544                         len1 = dotlen;
545                 }
546         }
547
548         if (write_in_full(fd, "[", 1) != 1 ||
549             write_in_full(fd, key, len1) != len1)
550                 return 0;
551         if (len2 >= 0) {
552                 if (write_in_full(fd, " \"", 2) != 2)
553                         return 0;
554                 while (--len2 >= 0) {
555                         unsigned char c = *++dot;
556                         if (c == '"')
557                                 if (write_in_full(fd, "\\", 1) != 1)
558                                         return 0;
559                         if (write_in_full(fd, &c, 1) != 1)
560                                 return 0;
561                 }
562                 if (write_in_full(fd, "\"", 1) != 1)
563                         return 0;
564         }
565         if (write_in_full(fd, "]\n", 2) != 2)
566                 return 0;
567
568         return 1;
569 }
570
571 static int store_write_pair(int fd, const char* key, const char* value)
572 {
573         int i;
574         int length = strlen(key+store.baselen+1);
575         int quote = 0;
576
577         /* Check to see if the value needs to be quoted. */
578         if (value[0] == ' ')
579                 quote = 1;
580         for (i = 0; value[i]; i++)
581                 if (value[i] == ';' || value[i] == '#')
582                         quote = 1;
583         if (value[i-1] == ' ')
584                 quote = 1;
585
586         if (write_in_full(fd, "\t", 1) != 1 ||
587             write_in_full(fd, key+store.baselen+1, length) != length ||
588             write_in_full(fd, " = ", 3) != 3)
589                 return 0;
590         if (quote && write_in_full(fd, "\"", 1) != 1)
591                 return 0;
592         for (i = 0; value[i]; i++)
593                 switch (value[i]) {
594                 case '\n':
595                         if (write_in_full(fd, "\\n", 2) != 2)
596                                 return 0;
597                         break;
598                 case '\t':
599                         if (write_in_full(fd, "\\t", 2) != 2)
600                                 return 0;
601                         break;
602                 case '"':
603                 case '\\':
604                         if (write_in_full(fd, "\\", 1) != 1)
605                                 return 0;
606                 default:
607                         if (write_in_full(fd, value+i, 1) != 1)
608                                 return 0;
609                         break;
610                 }
611         if (quote && write_in_full(fd, "\"", 1) != 1)
612                 return 0;
613         if (write_in_full(fd, "\n", 1) != 1)
614                 return 0;
615         return 1;
616 }
617
618 static ssize_t find_beginning_of_line(const char* contents, size_t size,
619         size_t offset_, int* found_bracket)
620 {
621         size_t equal_offset = size, bracket_offset = size;
622         ssize_t offset;
623
624         for (offset = offset_-2; offset > 0
625                         && contents[offset] != '\n'; offset--)
626                 switch (contents[offset]) {
627                         case '=': equal_offset = offset; break;
628                         case ']': bracket_offset = offset; break;
629                 }
630         if (bracket_offset < equal_offset) {
631                 *found_bracket = 1;
632                 offset = bracket_offset+1;
633         } else
634                 offset++;
635
636         return offset;
637 }
638
639 int git_config_set(const char* key, const char* value)
640 {
641         return git_config_set_multivar(key, value, NULL, 0);
642 }
643
644 /*
645  * If value==NULL, unset in (remove from) config,
646  * if value_regex!=NULL, disregard key/value pairs where value does not match.
647  * if multi_replace==0, nothing, or only one matching key/value is replaced,
648  *     else all matching key/values (regardless how many) are removed,
649  *     before the new pair is written.
650  *
651  * Returns 0 on success.
652  *
653  * This function does this:
654  *
655  * - it locks the config file by creating ".git/config.lock"
656  *
657  * - it then parses the config using store_aux() as validator to find
658  *   the position on the key/value pair to replace. If it is to be unset,
659  *   it must be found exactly once.
660  *
661  * - the config file is mmap()ed and the part before the match (if any) is
662  *   written to the lock file, then the changed part and the rest.
663  *
664  * - the config file is removed and the lock file rename()d to it.
665  *
666  */
667 int git_config_set_multivar(const char* key, const char* value,
668         const char* value_regex, int multi_replace)
669 {
670         int i, dot;
671         int fd = -1, in_fd;
672         int ret;
673         char* config_filename;
674         char* lock_file;
675         const char* last_dot = strrchr(key, '.');
676
677         config_filename = getenv(CONFIG_ENVIRONMENT);
678         if (!config_filename) {
679                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
680                 if (!config_filename)
681                         config_filename  = git_path("config");
682         }
683         config_filename = xstrdup(config_filename);
684         lock_file = xstrdup(mkpath("%s.lock", config_filename));
685
686         /*
687          * Since "key" actually contains the section name and the real
688          * key name separated by a dot, we have to know where the dot is.
689          */
690
691         if (last_dot == NULL) {
692                 fprintf(stderr, "key does not contain a section: %s\n", key);
693                 ret = 2;
694                 goto out_free;
695         }
696         store.baselen = last_dot - key;
697
698         store.multi_replace = multi_replace;
699
700         /*
701          * Validate the key and while at it, lower case it for matching.
702          */
703         store.key = xmalloc(strlen(key) + 1);
704         dot = 0;
705         for (i = 0; key[i]; i++) {
706                 unsigned char c = key[i];
707                 if (c == '.')
708                         dot = 1;
709                 /* Leave the extended basename untouched.. */
710                 if (!dot || i > store.baselen) {
711                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
712                                 fprintf(stderr, "invalid key: %s\n", key);
713                                 free(store.key);
714                                 ret = 1;
715                                 goto out_free;
716                         }
717                         c = tolower(c);
718                 } else if (c == '\n') {
719                         fprintf(stderr, "invalid key (newline): %s\n", key);
720                         free(store.key);
721                         ret = 1;
722                         goto out_free;
723                 }
724                 store.key[i] = c;
725         }
726         store.key[i] = 0;
727
728         /*
729          * The lock_file serves a purpose in addition to locking: the new
730          * contents of .git/config will be written into it.
731          */
732         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
733         if (fd < 0 || adjust_shared_perm(lock_file)) {
734                 fprintf(stderr, "could not lock config file\n");
735                 free(store.key);
736                 ret = -1;
737                 goto out_free;
738         }
739
740         /*
741          * If .git/config does not exist yet, write a minimal version.
742          */
743         in_fd = open(config_filename, O_RDONLY);
744         if ( in_fd < 0 ) {
745                 free(store.key);
746
747                 if ( ENOENT != errno ) {
748                         error("opening %s: %s", config_filename,
749                               strerror(errno));
750                         ret = 3; /* same as "invalid config file" */
751                         goto out_free;
752                 }
753                 /* if nothing to unset, error out */
754                 if (value == NULL) {
755                         ret = 5;
756                         goto out_free;
757                 }
758
759                 store.key = (char*)key;
760                 if (!store_write_section(fd, key) ||
761                     !store_write_pair(fd, key, value))
762                         goto write_err_out;
763         } else {
764                 struct stat st;
765                 char* contents;
766                 size_t contents_sz, copy_begin, copy_end;
767                 int i, new_line = 0;
768
769                 if (value_regex == NULL)
770                         store.value_regex = NULL;
771                 else {
772                         if (value_regex[0] == '!') {
773                                 store.do_not_match = 1;
774                                 value_regex++;
775                         } else
776                                 store.do_not_match = 0;
777
778                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
779                         if (regcomp(store.value_regex, value_regex,
780                                         REG_EXTENDED)) {
781                                 fprintf(stderr, "Invalid pattern: %s\n",
782                                         value_regex);
783                                 free(store.value_regex);
784                                 ret = 6;
785                                 goto out_free;
786                         }
787                 }
788
789                 store.offset[0] = 0;
790                 store.state = START;
791                 store.seen = 0;
792
793                 /*
794                  * After this, store.offset will contain the *end* offset
795                  * of the last match, or remain at 0 if no match was found.
796                  * As a side effect, we make sure to transform only a valid
797                  * existing config file.
798                  */
799                 if (git_config_from_file(store_aux, config_filename)) {
800                         fprintf(stderr, "invalid config file\n");
801                         free(store.key);
802                         if (store.value_regex != NULL) {
803                                 regfree(store.value_regex);
804                                 free(store.value_regex);
805                         }
806                         ret = 3;
807                         goto out_free;
808                 }
809
810                 free(store.key);
811                 if (store.value_regex != NULL) {
812                         regfree(store.value_regex);
813                         free(store.value_regex);
814                 }
815
816                 /* if nothing to unset, or too many matches, error out */
817                 if ((store.seen == 0 && value == NULL) ||
818                                 (store.seen > 1 && multi_replace == 0)) {
819                         ret = 5;
820                         goto out_free;
821                 }
822
823                 fstat(in_fd, &st);
824                 contents_sz = xsize_t(st.st_size);
825                 contents = xmmap(NULL, contents_sz, PROT_READ,
826                         MAP_PRIVATE, in_fd, 0);
827                 close(in_fd);
828
829                 if (store.seen == 0)
830                         store.seen = 1;
831
832                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
833                         if (store.offset[i] == 0) {
834                                 store.offset[i] = copy_end = contents_sz;
835                         } else if (store.state != KEY_SEEN) {
836                                 copy_end = store.offset[i];
837                         } else
838                                 copy_end = find_beginning_of_line(
839                                         contents, contents_sz,
840                                         store.offset[i]-2, &new_line);
841
842                         /* write the first part of the config */
843                         if (copy_end > copy_begin) {
844                                 if (write_in_full(fd, contents + copy_begin,
845                                                   copy_end - copy_begin) <
846                                     copy_end - copy_begin)
847                                         goto write_err_out;
848                                 if (new_line &&
849                                     write_in_full(fd, "\n", 1) != 1)
850                                         goto write_err_out;
851                         }
852                         copy_begin = store.offset[i];
853                 }
854
855                 /* write the pair (value == NULL means unset) */
856                 if (value != NULL) {
857                         if (store.state == START) {
858                                 if (!store_write_section(fd, key))
859                                         goto write_err_out;
860                         }
861                         if (!store_write_pair(fd, key, value))
862                                 goto write_err_out;
863                 }
864
865                 /* write the rest of the config */
866                 if (copy_begin < contents_sz)
867                         if (write_in_full(fd, contents + copy_begin,
868                                           contents_sz - copy_begin) <
869                             contents_sz - copy_begin)
870                                 goto write_err_out;
871
872                 munmap(contents, contents_sz);
873                 unlink(config_filename);
874         }
875
876         if (rename(lock_file, config_filename) < 0) {
877                 fprintf(stderr, "Could not rename the lock file?\n");
878                 ret = 4;
879                 goto out_free;
880         }
881
882         ret = 0;
883
884 out_free:
885         if (0 <= fd)
886                 close(fd);
887         free(config_filename);
888         if (lock_file) {
889                 unlink(lock_file);
890                 free(lock_file);
891         }
892         return ret;
893
894 write_err_out:
895         ret = write_error();
896         goto out_free;
897
898 }
899
900 static int section_name_match (const char *buf, const char *name)
901 {
902         int i = 0, j = 0, dot = 0;
903         for (; buf[i] && buf[i] != ']'; i++) {
904                 if (!dot && isspace(buf[i])) {
905                         dot = 1;
906                         if (name[j++] != '.')
907                                 break;
908                         for (i++; isspace(buf[i]); i++)
909                                 ; /* do nothing */
910                         if (buf[i] != '"')
911                                 break;
912                         continue;
913                 }
914                 if (buf[i] == '\\' && dot)
915                         i++;
916                 else if (buf[i] == '"' && dot) {
917                         for (i++; isspace(buf[i]); i++)
918                                 ; /* do_nothing */
919                         break;
920                 }
921                 if (buf[i] != name[j++])
922                         break;
923         }
924         return (buf[i] == ']' && name[j] == 0);
925 }
926
927 /* if new_name == NULL, the section is removed instead */
928 int git_config_rename_section(const char *old_name, const char *new_name)
929 {
930         int ret = 0, remove = 0;
931         char *config_filename;
932         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
933         int out_fd;
934         char buf[1024];
935
936         config_filename = getenv(CONFIG_ENVIRONMENT);
937         if (!config_filename) {
938                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
939                 if (!config_filename)
940                         config_filename  = git_path("config");
941         }
942         config_filename = xstrdup(config_filename);
943         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
944         if (out_fd < 0) {
945                 ret = error("Could not lock config file!");
946                 goto out;
947         }
948
949         if (!(config_file = fopen(config_filename, "rb"))) {
950                 /* no config file means nothing to rename, no error */
951                 goto unlock_and_out;
952         }
953
954         while (fgets(buf, sizeof(buf), config_file)) {
955                 int i;
956                 int length;
957                 for (i = 0; buf[i] && isspace(buf[i]); i++)
958                         ; /* do nothing */
959                 if (buf[i] == '[') {
960                         /* it's a section */
961                         if (section_name_match (&buf[i+1], old_name)) {
962                                 ret++;
963                                 if (new_name == NULL) {
964                                         remove = 1;
965                                         continue;
966                                 }
967                                 store.baselen = strlen(new_name);
968                                 if (!store_write_section(out_fd, new_name)) {
969                                         ret = write_error();
970                                         goto out;
971                                 }
972                                 continue;
973                         }
974                         remove = 0;
975                 }
976                 if (remove)
977                         continue;
978                 length = strlen(buf);
979                 if (write_in_full(out_fd, buf, length) != length) {
980                         ret = write_error();
981                         goto out;
982                 }
983         }
984         fclose(config_file);
985  unlock_and_out:
986         if (close(out_fd) || commit_lock_file(lock) < 0)
987                         ret = error("Cannot commit config file!");
988  out:
989         free(config_filename);
990         return ret;
991 }