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