Merge branch 'maint' of git://repo.or.cz/git/fastimport into 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 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.symlinks")) {
273                 has_symlinks = git_config_bool(var, value);
274                 return 0;
275         }
276
277         if (!strcmp(var, "core.bare")) {
278                 is_bare_repository_cfg = git_config_bool(var, value);
279                 return 0;
280         }
281
282         if (!strcmp(var, "core.ignorestat")) {
283                 assume_unchanged = git_config_bool(var, value);
284                 return 0;
285         }
286
287         if (!strcmp(var, "core.prefersymlinkrefs")) {
288                 prefer_symlink_refs = git_config_bool(var, value);
289                 return 0;
290         }
291
292         if (!strcmp(var, "core.logallrefupdates")) {
293                 log_all_ref_updates = git_config_bool(var, value);
294                 return 0;
295         }
296
297         if (!strcmp(var, "core.warnambiguousrefs")) {
298                 warn_ambiguous_refs = git_config_bool(var, value);
299                 return 0;
300         }
301
302         if (!strcmp(var, "core.legacyheaders")) {
303                 use_legacy_headers = git_config_bool(var, value);
304                 return 0;
305         }
306
307         if (!strcmp(var, "core.compression")) {
308                 int level = git_config_int(var, value);
309                 if (level == -1)
310                         level = Z_DEFAULT_COMPRESSION;
311                 else if (level < 0 || level > Z_BEST_COMPRESSION)
312                         die("bad zlib compression level %d", level);
313                 zlib_compression_level = level;
314                 return 0;
315         }
316
317         if (!strcmp(var, "core.packedgitwindowsize")) {
318                 int pgsz_x2 = getpagesize() * 2;
319                 packed_git_window_size = git_config_int(var, value);
320
321                 /* This value must be multiple of (pagesize * 2) */
322                 packed_git_window_size /= pgsz_x2;
323                 if (packed_git_window_size < 1)
324                         packed_git_window_size = 1;
325                 packed_git_window_size *= pgsz_x2;
326                 return 0;
327         }
328
329         if (!strcmp(var, "core.packedgitlimit")) {
330                 packed_git_limit = git_config_int(var, value);
331                 return 0;
332         }
333
334         if (!strcmp(var, "core.deltabasecachelimit")) {
335                 delta_base_cache_limit = git_config_int(var, value);
336                 return 0;
337         }
338
339         if (!strcmp(var, "core.autocrlf")) {
340                 if (value && !strcasecmp(value, "input")) {
341                         auto_crlf = -1;
342                         return 0;
343                 }
344                 auto_crlf = git_config_bool(var, value);
345                 return 0;
346         }
347
348         if (!strcmp(var, "user.name")) {
349                 strlcpy(git_default_name, value, sizeof(git_default_name));
350                 return 0;
351         }
352
353         if (!strcmp(var, "user.email")) {
354                 strlcpy(git_default_email, value, sizeof(git_default_email));
355                 return 0;
356         }
357
358         if (!strcmp(var, "i18n.commitencoding")) {
359                 git_commit_encoding = xstrdup(value);
360                 return 0;
361         }
362
363         if (!strcmp(var, "i18n.logoutputencoding")) {
364                 git_log_output_encoding = xstrdup(value);
365                 return 0;
366         }
367
368
369         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
370                 pager_use_color = git_config_bool(var,value);
371                 return 0;
372         }
373
374         /* Add other config variables here and to Documentation/config.txt. */
375         return 0;
376 }
377
378 int git_config_from_file(config_fn_t fn, const char *filename)
379 {
380         int ret;
381         FILE *f = fopen(filename, "r");
382
383         ret = -1;
384         if (f) {
385                 config_file = f;
386                 config_file_name = filename;
387                 config_linenr = 1;
388                 ret = git_parse_file(fn);
389                 fclose(f);
390                 config_file_name = NULL;
391         }
392         return ret;
393 }
394
395 int git_config(config_fn_t fn)
396 {
397         int ret = 0;
398         char *repo_config = NULL;
399         const char *home = NULL, *filename;
400
401         /* $GIT_CONFIG makes git read _only_ the given config file,
402          * $GIT_CONFIG_LOCAL will make it process it in addition to the
403          * global config file, the same way it would the per-repository
404          * config file otherwise. */
405         filename = getenv(CONFIG_ENVIRONMENT);
406         if (!filename) {
407                 if (!access(ETC_GITCONFIG, R_OK))
408                         ret += git_config_from_file(fn, ETC_GITCONFIG);
409                 home = getenv("HOME");
410                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
411                 if (!filename)
412                         filename = repo_config = xstrdup(git_path("config"));
413         }
414
415         if (home) {
416                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
417                 if (!access(user_config, R_OK))
418                         ret = git_config_from_file(fn, user_config);
419                 free(user_config);
420         }
421
422         ret += git_config_from_file(fn, filename);
423         free(repo_config);
424         return ret;
425 }
426
427 /*
428  * Find all the stuff for git_config_set() below.
429  */
430
431 #define MAX_MATCHES 512
432
433 static struct {
434         int baselen;
435         char* key;
436         int do_not_match;
437         regex_t* value_regex;
438         int multi_replace;
439         size_t offset[MAX_MATCHES];
440         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
441         int seen;
442 } store;
443
444 static int matches(const char* key, const char* value)
445 {
446         return !strcmp(key, store.key) &&
447                 (store.value_regex == NULL ||
448                  (store.do_not_match ^
449                   !regexec(store.value_regex, value, 0, NULL, 0)));
450 }
451
452 static int store_aux(const char* key, const char* value)
453 {
454         const char *ep;
455         size_t section_len;
456
457         switch (store.state) {
458         case KEY_SEEN:
459                 if (matches(key, value)) {
460                         if (store.seen == 1 && store.multi_replace == 0) {
461                                 fprintf(stderr,
462                                         "Warning: %s has multiple values\n",
463                                         key);
464                         } else if (store.seen >= MAX_MATCHES) {
465                                 fprintf(stderr, "Too many matches\n");
466                                 return 1;
467                         }
468
469                         store.offset[store.seen] = ftell(config_file);
470                         store.seen++;
471                 }
472                 break;
473         case SECTION_SEEN:
474                 /*
475                  * What we are looking for is in store.key (both
476                  * section and var), and its section part is baselen
477                  * long.  We found key (again, both section and var).
478                  * We would want to know if this key is in the same
479                  * section as what we are looking for.  We already
480                  * know we are in the same section as what should
481                  * hold store.key.
482                  */
483                 ep = strrchr(key, '.');
484                 section_len = ep - key;
485
486                 if ((section_len != store.baselen) ||
487                     memcmp(key, store.key, section_len+1)) {
488                         store.state = SECTION_END_SEEN;
489                         break;
490                 }
491
492                 /*
493                  * Do not increment matches: this is no match, but we
494                  * just made sure we are in the desired section.
495                  */
496                 store.offset[store.seen] = ftell(config_file);
497                 /* fallthru */
498         case SECTION_END_SEEN:
499         case START:
500                 if (matches(key, value)) {
501                         store.offset[store.seen] = ftell(config_file);
502                         store.state = KEY_SEEN;
503                         store.seen++;
504                 } else {
505                         if (strrchr(key, '.') - key == store.baselen &&
506                               !strncmp(key, store.key, store.baselen)) {
507                                         store.state = SECTION_SEEN;
508                                         store.offset[store.seen] = ftell(config_file);
509                         }
510                 }
511         }
512         return 0;
513 }
514
515 static int write_error()
516 {
517         fprintf(stderr, "Failed to write new configuration file\n");
518
519         /* Same error code as "failed to rename". */
520         return 4;
521 }
522
523 static int store_write_section(int fd, const char* key)
524 {
525         const char *dot = strchr(key, '.');
526         int len1 = store.baselen, len2 = -1;
527
528         dot = strchr(key, '.');
529         if (dot) {
530                 int dotlen = dot - key;
531                 if (dotlen < len1) {
532                         len2 = len1 - dotlen - 1;
533                         len1 = dotlen;
534                 }
535         }
536
537         if (write_in_full(fd, "[", 1) != 1 ||
538             write_in_full(fd, key, len1) != len1)
539                 return 0;
540         if (len2 >= 0) {
541                 if (write_in_full(fd, " \"", 2) != 2)
542                         return 0;
543                 while (--len2 >= 0) {
544                         unsigned char c = *++dot;
545                         if (c == '"')
546                                 if (write_in_full(fd, "\\", 1) != 1)
547                                         return 0;
548                         if (write_in_full(fd, &c, 1) != 1)
549                                 return 0;
550                 }
551                 if (write_in_full(fd, "\"", 1) != 1)
552                         return 0;
553         }
554         if (write_in_full(fd, "]\n", 2) != 2)
555                 return 0;
556
557         return 1;
558 }
559
560 static int store_write_pair(int fd, const char* key, const char* value)
561 {
562         int i;
563         int length = strlen(key+store.baselen+1);
564         int quote = 0;
565
566         /* Check to see if the value needs to be quoted. */
567         if (value[0] == ' ')
568                 quote = 1;
569         for (i = 0; value[i]; i++)
570                 if (value[i] == ';' || value[i] == '#')
571                         quote = 1;
572         if (value[i-1] == ' ')
573                 quote = 1;
574
575         if (write_in_full(fd, "\t", 1) != 1 ||
576             write_in_full(fd, key+store.baselen+1, length) != length ||
577             write_in_full(fd, " = ", 3) != 3)
578                 return 0;
579         if (quote && write_in_full(fd, "\"", 1) != 1)
580                 return 0;
581         for (i = 0; value[i]; i++)
582                 switch (value[i]) {
583                 case '\n':
584                         if (write_in_full(fd, "\\n", 2) != 2)
585                                 return 0;
586                         break;
587                 case '\t':
588                         if (write_in_full(fd, "\\t", 2) != 2)
589                                 return 0;
590                         break;
591                 case '"':
592                 case '\\':
593                         if (write_in_full(fd, "\\", 1) != 1)
594                                 return 0;
595                 default:
596                         if (write_in_full(fd, value+i, 1) != 1)
597                                 return 0;
598                         break;
599                 }
600         if (quote && write_in_full(fd, "\"", 1) != 1)
601                 return 0;
602         if (write_in_full(fd, "\n", 1) != 1)
603                 return 0;
604         return 1;
605 }
606
607 static ssize_t find_beginning_of_line(const char* contents, size_t size,
608         size_t offset_, int* found_bracket)
609 {
610         size_t equal_offset = size, bracket_offset = size;
611         ssize_t offset;
612
613         for (offset = offset_-2; offset > 0 
614                         && contents[offset] != '\n'; offset--)
615                 switch (contents[offset]) {
616                         case '=': equal_offset = offset; break;
617                         case ']': bracket_offset = offset; break;
618                 }
619         if (bracket_offset < equal_offset) {
620                 *found_bracket = 1;
621                 offset = bracket_offset+1;
622         } else
623                 offset++;
624
625         return offset;
626 }
627
628 int git_config_set(const char* key, const char* value)
629 {
630         return git_config_set_multivar(key, value, NULL, 0);
631 }
632
633 /*
634  * If value==NULL, unset in (remove from) config,
635  * if value_regex!=NULL, disregard key/value pairs where value does not match.
636  * if multi_replace==0, nothing, or only one matching key/value is replaced,
637  *     else all matching key/values (regardless how many) are removed,
638  *     before the new pair is written.
639  *
640  * Returns 0 on success.
641  *
642  * This function does this:
643  *
644  * - it locks the config file by creating ".git/config.lock"
645  *
646  * - it then parses the config using store_aux() as validator to find
647  *   the position on the key/value pair to replace. If it is to be unset,
648  *   it must be found exactly once.
649  *
650  * - the config file is mmap()ed and the part before the match (if any) is
651  *   written to the lock file, then the changed part and the rest.
652  *
653  * - the config file is removed and the lock file rename()d to it.
654  *
655  */
656 int git_config_set_multivar(const char* key, const char* value,
657         const char* value_regex, int multi_replace)
658 {
659         int i, dot;
660         int fd = -1, in_fd;
661         int ret;
662         char* config_filename;
663         char* lock_file;
664         const char* last_dot = strrchr(key, '.');
665
666         config_filename = getenv(CONFIG_ENVIRONMENT);
667         if (!config_filename) {
668                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
669                 if (!config_filename)
670                         config_filename  = git_path("config");
671         }
672         config_filename = xstrdup(config_filename);
673         lock_file = xstrdup(mkpath("%s.lock", config_filename));
674
675         /*
676          * Since "key" actually contains the section name and the real
677          * key name separated by a dot, we have to know where the dot is.
678          */
679
680         if (last_dot == NULL) {
681                 fprintf(stderr, "key does not contain a section: %s\n", key);
682                 ret = 2;
683                 goto out_free;
684         }
685         store.baselen = last_dot - key;
686
687         store.multi_replace = multi_replace;
688
689         /*
690          * Validate the key and while at it, lower case it for matching.
691          */
692         store.key = xmalloc(strlen(key) + 1);
693         dot = 0;
694         for (i = 0; key[i]; i++) {
695                 unsigned char c = key[i];
696                 if (c == '.')
697                         dot = 1;
698                 /* Leave the extended basename untouched.. */
699                 if (!dot || i > store.baselen) {
700                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
701                                 fprintf(stderr, "invalid key: %s\n", key);
702                                 free(store.key);
703                                 ret = 1;
704                                 goto out_free;
705                         }
706                         c = tolower(c);
707                 } else if (c == '\n') {
708                         fprintf(stderr, "invalid key (newline): %s\n", key);
709                         free(store.key);
710                         ret = 1;
711                         goto out_free;
712                 }
713                 store.key[i] = c;
714         }
715         store.key[i] = 0;
716
717         /*
718          * The lock_file serves a purpose in addition to locking: the new
719          * contents of .git/config will be written into it.
720          */
721         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
722         if (fd < 0 || adjust_shared_perm(lock_file)) {
723                 fprintf(stderr, "could not lock config file\n");
724                 free(store.key);
725                 ret = -1;
726                 goto out_free;
727         }
728
729         /*
730          * If .git/config does not exist yet, write a minimal version.
731          */
732         in_fd = open(config_filename, O_RDONLY);
733         if ( in_fd < 0 ) {
734                 free(store.key);
735
736                 if ( ENOENT != errno ) {
737                         error("opening %s: %s", config_filename,
738                               strerror(errno));
739                         ret = 3; /* same as "invalid config file" */
740                         goto out_free;
741                 }
742                 /* if nothing to unset, error out */
743                 if (value == NULL) {
744                         ret = 5;
745                         goto out_free;
746                 }
747
748                 store.key = (char*)key;
749                 if (!store_write_section(fd, key) ||
750                     !store_write_pair(fd, key, value))
751                         goto write_err_out;
752         } else {
753                 struct stat st;
754                 char* contents;
755                 size_t contents_sz, copy_begin, copy_end;
756                 int i, new_line = 0;
757
758                 if (value_regex == NULL)
759                         store.value_regex = NULL;
760                 else {
761                         if (value_regex[0] == '!') {
762                                 store.do_not_match = 1;
763                                 value_regex++;
764                         } else
765                                 store.do_not_match = 0;
766
767                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
768                         if (regcomp(store.value_regex, value_regex,
769                                         REG_EXTENDED)) {
770                                 fprintf(stderr, "Invalid pattern: %s\n",
771                                         value_regex);
772                                 free(store.value_regex);
773                                 ret = 6;
774                                 goto out_free;
775                         }
776                 }
777
778                 store.offset[0] = 0;
779                 store.state = START;
780                 store.seen = 0;
781
782                 /*
783                  * After this, store.offset will contain the *end* offset
784                  * of the last match, or remain at 0 if no match was found.
785                  * As a side effect, we make sure to transform only a valid
786                  * existing config file.
787                  */
788                 if (git_config_from_file(store_aux, config_filename)) {
789                         fprintf(stderr, "invalid config file\n");
790                         free(store.key);
791                         if (store.value_regex != NULL) {
792                                 regfree(store.value_regex);
793                                 free(store.value_regex);
794                         }
795                         ret = 3;
796                         goto out_free;
797                 }
798
799                 free(store.key);
800                 if (store.value_regex != NULL) {
801                         regfree(store.value_regex);
802                         free(store.value_regex);
803                 }
804
805                 /* if nothing to unset, or too many matches, error out */
806                 if ((store.seen == 0 && value == NULL) ||
807                                 (store.seen > 1 && multi_replace == 0)) {
808                         ret = 5;
809                         goto out_free;
810                 }
811
812                 fstat(in_fd, &st);
813                 contents_sz = xsize_t(st.st_size);
814                 contents = xmmap(NULL, contents_sz, PROT_READ,
815                         MAP_PRIVATE, in_fd, 0);
816                 close(in_fd);
817
818                 if (store.seen == 0)
819                         store.seen = 1;
820
821                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
822                         if (store.offset[i] == 0) {
823                                 store.offset[i] = copy_end = contents_sz;
824                         } else if (store.state != KEY_SEEN) {
825                                 copy_end = store.offset[i];
826                         } else
827                                 copy_end = find_beginning_of_line(
828                                         contents, contents_sz,
829                                         store.offset[i]-2, &new_line);
830
831                         /* write the first part of the config */
832                         if (copy_end > copy_begin) {
833                                 if (write_in_full(fd, contents + copy_begin,
834                                                   copy_end - copy_begin) <
835                                     copy_end - copy_begin)
836                                         goto write_err_out;
837                                 if (new_line &&
838                                     write_in_full(fd, "\n", 1) != 1)
839                                         goto write_err_out;
840                         }
841                         copy_begin = store.offset[i];
842                 }
843
844                 /* write the pair (value == NULL means unset) */
845                 if (value != NULL) {
846                         if (store.state == START) {
847                                 if (!store_write_section(fd, key))
848                                         goto write_err_out;
849                         }
850                         if (!store_write_pair(fd, key, value))
851                                 goto write_err_out;
852                 }
853
854                 /* write the rest of the config */
855                 if (copy_begin < contents_sz)
856                         if (write_in_full(fd, contents + copy_begin,
857                                           contents_sz - copy_begin) <
858                             contents_sz - copy_begin)
859                                 goto write_err_out;
860
861                 munmap(contents, contents_sz);
862                 unlink(config_filename);
863         }
864
865         if (rename(lock_file, config_filename) < 0) {
866                 fprintf(stderr, "Could not rename the lock file?\n");
867                 ret = 4;
868                 goto out_free;
869         }
870
871         ret = 0;
872
873 out_free:
874         if (0 <= fd)
875                 close(fd);
876         free(config_filename);
877         if (lock_file) {
878                 unlink(lock_file);
879                 free(lock_file);
880         }
881         return ret;
882
883 write_err_out:
884         ret = write_error();
885         goto out_free;
886
887 }
888
889 static int section_name_match (const char *buf, const char *name)
890 {
891         int i = 0, j = 0, dot = 0;
892         for (; buf[i] && buf[i] != ']'; i++) {
893                 if (!dot && isspace(buf[i])) {
894                         dot = 1;
895                         if (name[j++] != '.')
896                                 break;
897                         for (i++; isspace(buf[i]); i++)
898                                 ; /* do nothing */
899                         if (buf[i] != '"')
900                                 break;
901                         continue;
902                 }
903                 if (buf[i] == '\\' && dot)
904                         i++;
905                 else if (buf[i] == '"' && dot) {
906                         for (i++; isspace(buf[i]); i++)
907                                 ; /* do_nothing */
908                         break;
909                 }
910                 if (buf[i] != name[j++])
911                         break;
912         }
913         return (buf[i] == ']' && name[j] == 0);
914 }
915
916 /* if new_name == NULL, the section is removed instead */
917 int git_config_rename_section(const char *old_name, const char *new_name)
918 {
919         int ret = 0, remove = 0;
920         char *config_filename;
921         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
922         int out_fd;
923         char buf[1024];
924
925         config_filename = getenv(CONFIG_ENVIRONMENT);
926         if (!config_filename) {
927                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
928                 if (!config_filename)
929                         config_filename  = git_path("config");
930         }
931         config_filename = xstrdup(config_filename);
932         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
933         if (out_fd < 0) {
934                 ret = error("Could not lock config file!");
935                 goto out;
936         }
937
938         if (!(config_file = fopen(config_filename, "rb"))) {
939                 /* no config file means nothing to rename, no error */
940                 goto unlock_and_out;
941         }
942
943         while (fgets(buf, sizeof(buf), config_file)) {
944                 int i;
945                 int length;
946                 for (i = 0; buf[i] && isspace(buf[i]); i++)
947                         ; /* do nothing */
948                 if (buf[i] == '[') {
949                         /* it's a section */
950                         if (section_name_match (&buf[i+1], old_name)) {
951                                 ret++;
952                                 if (new_name == NULL) {
953                                         remove = 1;
954                                         continue;
955                                 }
956                                 store.baselen = strlen(new_name);
957                                 if (!store_write_section(out_fd, new_name)) {
958                                         ret = write_error();
959                                         goto out;
960                                 }
961                                 continue;
962                         }
963                         remove = 0;
964                 }
965                 if (remove)
966                         continue;
967                 length = strlen(buf);
968                 if (write_in_full(out_fd, buf, length) != length) {
969                         ret = write_error();
970                         goto out;
971                 }
972         }
973         fclose(config_file);
974  unlock_and_out:
975         if (close(out_fd) || commit_lock_file(lock) < 0)
976                         ret = error("Cannot commit config file!");
977  out:
978         free(config_filename);
979         return ret;
980 }
981