Merge branch 'rs/pretty-safety'
[git] / config.c
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  * Copyright (C) Johannes Schindelin, 2005
6  *
7  */
8 #include "cache.h"
9 #include "exec_cmd.h"
10
11 #define MAXNAME (256)
12
13 static FILE *config_file;
14 static const char *config_file_name;
15 static int config_linenr;
16 static int zlib_compression_seen;
17
18 static int get_next_char(void)
19 {
20         int c;
21         FILE *f;
22
23         c = '\n';
24         if ((f = config_file) != NULL) {
25                 c = fgetc(f);
26                 if (c == '\r') {
27                         /* DOS like systems */
28                         c = fgetc(f);
29                         if (c != '\n') {
30                                 ungetc(c, f);
31                                 c = '\r';
32                         }
33                 }
34                 if (c == '\n')
35                         config_linenr++;
36                 if (c == EOF) {
37                         config_file = NULL;
38                         c = '\n';
39                 }
40         }
41         return c;
42 }
43
44 static char *parse_value(void)
45 {
46         static char value[1024];
47         int quote = 0, comment = 0, len = 0, space = 0;
48
49         for (;;) {
50                 int c = get_next_char();
51                 if (len >= sizeof(value))
52                         return NULL;
53                 if (c == '\n') {
54                         if (quote)
55                                 return NULL;
56                         value[len] = 0;
57                         return value;
58                 }
59                 if (comment)
60                         continue;
61                 if (isspace(c) && !quote) {
62                         space = 1;
63                         continue;
64                 }
65                 if (!quote) {
66                         if (c == ';' || c == '#') {
67                                 comment = 1;
68                                 continue;
69                         }
70                 }
71                 if (space) {
72                         if (len)
73                                 value[len++] = ' ';
74                         space = 0;
75                 }
76                 if (c == '\\') {
77                         c = get_next_char();
78                         switch (c) {
79                         case '\n':
80                                 continue;
81                         case 't':
82                                 c = '\t';
83                                 break;
84                         case 'b':
85                                 c = '\b';
86                                 break;
87                         case 'n':
88                                 c = '\n';
89                                 break;
90                         /* Some characters escape as themselves */
91                         case '\\': case '"':
92                                 break;
93                         /* Reject unknown escape sequences */
94                         default:
95                                 return NULL;
96                         }
97                         value[len++] = c;
98                         continue;
99                 }
100                 if (c == '"') {
101                         quote = 1-quote;
102                         continue;
103                 }
104                 value[len++] = c;
105         }
106 }
107
108 static inline int iskeychar(int c)
109 {
110         return isalnum(c) || c == '-';
111 }
112
113 static int get_value(config_fn_t fn, char *name, unsigned int len)
114 {
115         int c;
116         char *value;
117
118         /* Get the full name */
119         for (;;) {
120                 c = get_next_char();
121                 if (c == EOF)
122                         break;
123                 if (!iskeychar(c))
124                         break;
125                 name[len++] = tolower(c);
126                 if (len >= MAXNAME)
127                         return -1;
128         }
129         name[len] = 0;
130         while (c == ' ' || c == '\t')
131                 c = get_next_char();
132
133         value = NULL;
134         if (c != '\n') {
135                 if (c != '=')
136                         return -1;
137                 value = parse_value();
138                 if (!value)
139                         return -1;
140         }
141         return fn(name, value);
142 }
143
144 static int get_extended_base_var(char *name, int baselen, int c)
145 {
146         do {
147                 if (c == '\n')
148                         return -1;
149                 c = get_next_char();
150         } while (isspace(c));
151
152         /* We require the format to be '[base "extension"]' */
153         if (c != '"')
154                 return -1;
155         name[baselen++] = '.';
156
157         for (;;) {
158                 int c = get_next_char();
159                 if (c == '\n')
160                         return -1;
161                 if (c == '"')
162                         break;
163                 if (c == '\\') {
164                         c = get_next_char();
165                         if (c == '\n')
166                                 return -1;
167                 }
168                 name[baselen++] = c;
169                 if (baselen > MAXNAME / 2)
170                         return -1;
171         }
172
173         /* Final ']' */
174         if (get_next_char() != ']')
175                 return -1;
176         return baselen;
177 }
178
179 static int get_base_var(char *name)
180 {
181         int baselen = 0;
182
183         for (;;) {
184                 int c = get_next_char();
185                 if (c == EOF)
186                         return -1;
187                 if (c == ']')
188                         return baselen;
189                 if (isspace(c))
190                         return get_extended_base_var(name, baselen, c);
191                 if (!iskeychar(c) && c != '.')
192                         return -1;
193                 if (baselen > MAXNAME / 2)
194                         return -1;
195                 name[baselen++] = tolower(c);
196         }
197 }
198
199 static int git_parse_file(config_fn_t fn)
200 {
201         int comment = 0;
202         int baselen = 0;
203         static char var[MAXNAME];
204
205         for (;;) {
206                 int c = get_next_char();
207                 if (c == '\n') {
208                         /* EOF? */
209                         if (!config_file)
210                                 return 0;
211                         comment = 0;
212                         continue;
213                 }
214                 if (comment || isspace(c))
215                         continue;
216                 if (c == '#' || c == ';') {
217                         comment = 1;
218                         continue;
219                 }
220                 if (c == '[') {
221                         baselen = get_base_var(var);
222                         if (baselen <= 0)
223                                 break;
224                         var[baselen++] = '.';
225                         var[baselen] = 0;
226                         continue;
227                 }
228                 if (!isalpha(c))
229                         break;
230                 var[baselen] = tolower(c);
231                 if (get_value(fn, var, baselen+1) < 0)
232                         break;
233         }
234         die("bad config file line %d in %s", config_linenr, config_file_name);
235 }
236
237 static int parse_unit_factor(const char *end, unsigned long *val)
238 {
239         if (!*end)
240                 return 1;
241         else if (!strcasecmp(end, "k")) {
242                 *val *= 1024;
243                 return 1;
244         }
245         else if (!strcasecmp(end, "m")) {
246                 *val *= 1024 * 1024;
247                 return 1;
248         }
249         else if (!strcasecmp(end, "g")) {
250                 *val *= 1024 * 1024 * 1024;
251                 return 1;
252         }
253         return 0;
254 }
255
256 int git_parse_long(const char *value, long *ret)
257 {
258         if (value && *value) {
259                 char *end;
260                 long val = strtol(value, &end, 0);
261                 unsigned long factor = 1;
262                 if (!parse_unit_factor(end, &factor))
263                         return 0;
264                 *ret = val * factor;
265                 return 1;
266         }
267         return 0;
268 }
269
270 int git_parse_ulong(const char *value, unsigned long *ret)
271 {
272         if (value && *value) {
273                 char *end;
274                 unsigned long val = strtoul(value, &end, 0);
275                 if (!parse_unit_factor(end, &val))
276                         return 0;
277                 *ret = val;
278                 return 1;
279         }
280         return 0;
281 }
282
283 int git_config_int(const char *name, const char *value)
284 {
285         long ret;
286         if (!git_parse_long(value, &ret))
287                 die("bad config value for '%s' in %s", name, config_file_name);
288         return ret;
289 }
290
291 unsigned long git_config_ulong(const char *name, const char *value)
292 {
293         unsigned long ret;
294         if (!git_parse_ulong(value, &ret))
295                 die("bad config value for '%s' in %s", name, config_file_name);
296         return ret;
297 }
298
299 int git_config_bool(const char *name, const char *value)
300 {
301         if (!value)
302                 return 1;
303         if (!*value)
304                 return 0;
305         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
306                 return 1;
307         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
308                 return 0;
309         return git_config_int(name, value) != 0;
310 }
311
312 int git_default_config(const char *var, const char *value)
313 {
314         /* This needs a better name */
315         if (!strcmp(var, "core.filemode")) {
316                 trust_executable_bit = git_config_bool(var, value);
317                 return 0;
318         }
319
320         if (!strcmp(var, "core.quotepath")) {
321                 quote_path_fully = git_config_bool(var, value);
322                 return 0;
323         }
324
325         if (!strcmp(var, "core.symlinks")) {
326                 has_symlinks = git_config_bool(var, value);
327                 return 0;
328         }
329
330         if (!strcmp(var, "core.bare")) {
331                 is_bare_repository_cfg = git_config_bool(var, value);
332                 return 0;
333         }
334
335         if (!strcmp(var, "core.ignorestat")) {
336                 assume_unchanged = git_config_bool(var, value);
337                 return 0;
338         }
339
340         if (!strcmp(var, "core.prefersymlinkrefs")) {
341                 prefer_symlink_refs = git_config_bool(var, value);
342                 return 0;
343         }
344
345         if (!strcmp(var, "core.logallrefupdates")) {
346                 log_all_ref_updates = git_config_bool(var, value);
347                 return 0;
348         }
349
350         if (!strcmp(var, "core.warnambiguousrefs")) {
351                 warn_ambiguous_refs = git_config_bool(var, value);
352                 return 0;
353         }
354
355         if (!strcmp(var, "core.loosecompression")) {
356                 int level = git_config_int(var, value);
357                 if (level == -1)
358                         level = Z_DEFAULT_COMPRESSION;
359                 else if (level < 0 || level > Z_BEST_COMPRESSION)
360                         die("bad zlib compression level %d", level);
361                 zlib_compression_level = level;
362                 zlib_compression_seen = 1;
363                 return 0;
364         }
365
366         if (!strcmp(var, "core.compression")) {
367                 int level = git_config_int(var, value);
368                 if (level == -1)
369                         level = Z_DEFAULT_COMPRESSION;
370                 else if (level < 0 || level > Z_BEST_COMPRESSION)
371                         die("bad zlib compression level %d", level);
372                 core_compression_level = level;
373                 core_compression_seen = 1;
374                 if (!zlib_compression_seen)
375                         zlib_compression_level = level;
376                 return 0;
377         }
378
379         if (!strcmp(var, "core.packedgitwindowsize")) {
380                 int pgsz_x2 = getpagesize() * 2;
381                 packed_git_window_size = git_config_int(var, value);
382
383                 /* This value must be multiple of (pagesize * 2) */
384                 packed_git_window_size /= pgsz_x2;
385                 if (packed_git_window_size < 1)
386                         packed_git_window_size = 1;
387                 packed_git_window_size *= pgsz_x2;
388                 return 0;
389         }
390
391         if (!strcmp(var, "core.packedgitlimit")) {
392                 packed_git_limit = git_config_int(var, value);
393                 return 0;
394         }
395
396         if (!strcmp(var, "core.deltabasecachelimit")) {
397                 delta_base_cache_limit = git_config_int(var, value);
398                 return 0;
399         }
400
401         if (!strcmp(var, "core.autocrlf")) {
402                 if (value && !strcasecmp(value, "input")) {
403                         auto_crlf = -1;
404                         return 0;
405                 }
406                 auto_crlf = git_config_bool(var, value);
407                 return 0;
408         }
409
410         if (!strcmp(var, "user.name")) {
411                 strlcpy(git_default_name, value, sizeof(git_default_name));
412                 return 0;
413         }
414
415         if (!strcmp(var, "user.email")) {
416                 strlcpy(git_default_email, value, sizeof(git_default_email));
417                 return 0;
418         }
419
420         if (!strcmp(var, "i18n.commitencoding")) {
421                 git_commit_encoding = xstrdup(value);
422                 return 0;
423         }
424
425         if (!strcmp(var, "i18n.logoutputencoding")) {
426                 git_log_output_encoding = xstrdup(value);
427                 return 0;
428         }
429
430
431         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
432                 pager_use_color = git_config_bool(var,value);
433                 return 0;
434         }
435
436         if (!strcmp(var, "core.pager")) {
437                 pager_program = xstrdup(value);
438                 return 0;
439         }
440
441         if (!strcmp(var, "core.editor")) {
442                 editor_program = xstrdup(value);
443                 return 0;
444         }
445
446         if (!strcmp(var, "core.excludesfile")) {
447                 if (!value)
448                         die("core.excludesfile without value");
449                 excludes_file = xstrdup(value);
450                 return 0;
451         }
452
453         if (!strcmp(var, "core.whitespace")) {
454                 whitespace_rule_cfg = parse_whitespace_rule(value);
455                 return 0;
456         }
457
458         /* Add other config variables here and to Documentation/config.txt. */
459         return 0;
460 }
461
462 int git_config_from_file(config_fn_t fn, const char *filename)
463 {
464         int ret;
465         FILE *f = fopen(filename, "r");
466
467         ret = -1;
468         if (f) {
469                 config_file = f;
470                 config_file_name = filename;
471                 config_linenr = 1;
472                 ret = git_parse_file(fn);
473                 fclose(f);
474                 config_file_name = NULL;
475         }
476         return ret;
477 }
478
479 const char *git_etc_gitconfig(void)
480 {
481         static const char *system_wide;
482         if (!system_wide) {
483                 system_wide = ETC_GITCONFIG;
484                 if (!is_absolute_path(system_wide)) {
485                         /* interpret path relative to exec-dir */
486                         const char *exec_path = git_exec_path();
487                         system_wide = prefix_path(exec_path, strlen(exec_path),
488                                                 system_wide);
489                 }
490         }
491         return system_wide;
492 }
493
494 int git_config(config_fn_t fn)
495 {
496         int ret = 0;
497         char *repo_config = NULL;
498         const char *home = NULL, *filename;
499
500         /* $GIT_CONFIG makes git read _only_ the given config file,
501          * $GIT_CONFIG_LOCAL will make it process it in addition to the
502          * global config file, the same way it would the per-repository
503          * config file otherwise. */
504         filename = getenv(CONFIG_ENVIRONMENT);
505         if (!filename) {
506                 if (!access(git_etc_gitconfig(), R_OK))
507                         ret += git_config_from_file(fn, git_etc_gitconfig());
508                 home = getenv("HOME");
509                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
510                 if (!filename)
511                         filename = repo_config = xstrdup(git_path("config"));
512         }
513
514         if (home) {
515                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
516                 if (!access(user_config, R_OK))
517                         ret = git_config_from_file(fn, user_config);
518                 free(user_config);
519         }
520
521         ret += git_config_from_file(fn, filename);
522         free(repo_config);
523         return ret;
524 }
525
526 /*
527  * Find all the stuff for git_config_set() below.
528  */
529
530 #define MAX_MATCHES 512
531
532 static struct {
533         int baselen;
534         char* key;
535         int do_not_match;
536         regex_t* value_regex;
537         int multi_replace;
538         size_t offset[MAX_MATCHES];
539         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
540         int seen;
541 } store;
542
543 static int matches(const char* key, const char* value)
544 {
545         return !strcmp(key, store.key) &&
546                 (store.value_regex == NULL ||
547                  (store.do_not_match ^
548                   !regexec(store.value_regex, value, 0, NULL, 0)));
549 }
550
551 static int store_aux(const char* key, const char* value)
552 {
553         const char *ep;
554         size_t section_len;
555
556         switch (store.state) {
557         case KEY_SEEN:
558                 if (matches(key, value)) {
559                         if (store.seen == 1 && store.multi_replace == 0) {
560                                 fprintf(stderr,
561                                         "Warning: %s has multiple values\n",
562                                         key);
563                         } else if (store.seen >= MAX_MATCHES) {
564                                 fprintf(stderr, "Too many matches\n");
565                                 return 1;
566                         }
567
568                         store.offset[store.seen] = ftell(config_file);
569                         store.seen++;
570                 }
571                 break;
572         case SECTION_SEEN:
573                 /*
574                  * What we are looking for is in store.key (both
575                  * section and var), and its section part is baselen
576                  * long.  We found key (again, both section and var).
577                  * We would want to know if this key is in the same
578                  * section as what we are looking for.  We already
579                  * know we are in the same section as what should
580                  * hold store.key.
581                  */
582                 ep = strrchr(key, '.');
583                 section_len = ep - key;
584
585                 if ((section_len != store.baselen) ||
586                     memcmp(key, store.key, section_len+1)) {
587                         store.state = SECTION_END_SEEN;
588                         break;
589                 }
590
591                 /*
592                  * Do not increment matches: this is no match, but we
593                  * just made sure we are in the desired section.
594                  */
595                 store.offset[store.seen] = ftell(config_file);
596                 /* fallthru */
597         case SECTION_END_SEEN:
598         case START:
599                 if (matches(key, value)) {
600                         store.offset[store.seen] = ftell(config_file);
601                         store.state = KEY_SEEN;
602                         store.seen++;
603                 } else {
604                         if (strrchr(key, '.') - key == store.baselen &&
605                               !strncmp(key, store.key, store.baselen)) {
606                                         store.state = SECTION_SEEN;
607                                         store.offset[store.seen] = ftell(config_file);
608                         }
609                 }
610         }
611         return 0;
612 }
613
614 static int write_error(void)
615 {
616         fprintf(stderr, "Failed to write new configuration file\n");
617
618         /* Same error code as "failed to rename". */
619         return 4;
620 }
621
622 static int store_write_section(int fd, const char* key)
623 {
624         const char *dot;
625         int i, success;
626         struct strbuf sb;
627
628         strbuf_init(&sb, 0);
629         dot = memchr(key, '.', store.baselen);
630         if (dot) {
631                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
632                 for (i = dot - key + 1; i < store.baselen; i++) {
633                         if (key[i] == '"')
634                                 strbuf_addch(&sb, '\\');
635                         strbuf_addch(&sb, key[i]);
636                 }
637                 strbuf_addstr(&sb, "\"]\n");
638         } else {
639                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
640         }
641
642         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
643         strbuf_release(&sb);
644
645         return success;
646 }
647
648 static int store_write_pair(int fd, const char* key, const char* value)
649 {
650         int i, success;
651         int length = strlen(key + store.baselen + 1);
652         const char *quote = "";
653         struct strbuf sb;
654
655         /*
656          * Check to see if the value needs to be surrounded with a dq pair.
657          * Note that problematic characters are always backslash-quoted; this
658          * check is about not losing leading or trailing SP and strings that
659          * follow beginning-of-comment characters (i.e. ';' and '#') by the
660          * configuration parser.
661          */
662         if (value[0] == ' ')
663                 quote = "\"";
664         for (i = 0; value[i]; i++)
665                 if (value[i] == ';' || value[i] == '#')
666                         quote = "\"";
667         if (i && value[i - 1] == ' ')
668                 quote = "\"";
669
670         strbuf_init(&sb, 0);
671         strbuf_addf(&sb, "\t%.*s = %s",
672                     length, key + store.baselen + 1, quote);
673
674         for (i = 0; value[i]; i++)
675                 switch (value[i]) {
676                 case '\n':
677                         strbuf_addstr(&sb, "\\n");
678                         break;
679                 case '\t':
680                         strbuf_addstr(&sb, "\\t");
681                         break;
682                 case '"':
683                 case '\\':
684                         strbuf_addch(&sb, '\\');
685                 default:
686                         strbuf_addch(&sb, value[i]);
687                         break;
688                 }
689         strbuf_addf(&sb, "%s\n", quote);
690
691         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
692         strbuf_release(&sb);
693
694         return success;
695 }
696
697 static ssize_t find_beginning_of_line(const char* contents, size_t size,
698         size_t offset_, int* found_bracket)
699 {
700         size_t equal_offset = size, bracket_offset = size;
701         ssize_t offset;
702
703         for (offset = offset_-2; offset > 0
704                         && contents[offset] != '\n'; offset--)
705                 switch (contents[offset]) {
706                         case '=': equal_offset = offset; break;
707                         case ']': bracket_offset = offset; break;
708                 }
709         if (bracket_offset < equal_offset) {
710                 *found_bracket = 1;
711                 offset = bracket_offset+1;
712         } else
713                 offset++;
714
715         return offset;
716 }
717
718 int git_config_set(const char* key, const char* value)
719 {
720         return git_config_set_multivar(key, value, NULL, 0);
721 }
722
723 /*
724  * If value==NULL, unset in (remove from) config,
725  * if value_regex!=NULL, disregard key/value pairs where value does not match.
726  * if multi_replace==0, nothing, or only one matching key/value is replaced,
727  *     else all matching key/values (regardless how many) are removed,
728  *     before the new pair is written.
729  *
730  * Returns 0 on success.
731  *
732  * This function does this:
733  *
734  * - it locks the config file by creating ".git/config.lock"
735  *
736  * - it then parses the config using store_aux() as validator to find
737  *   the position on the key/value pair to replace. If it is to be unset,
738  *   it must be found exactly once.
739  *
740  * - the config file is mmap()ed and the part before the match (if any) is
741  *   written to the lock file, then the changed part and the rest.
742  *
743  * - the config file is removed and the lock file rename()d to it.
744  *
745  */
746 int git_config_set_multivar(const char* key, const char* value,
747         const char* value_regex, int multi_replace)
748 {
749         int i, dot;
750         int fd = -1, in_fd;
751         int ret;
752         char* config_filename;
753         struct lock_file *lock = NULL;
754         const char* last_dot = strrchr(key, '.');
755
756         config_filename = getenv(CONFIG_ENVIRONMENT);
757         if (!config_filename) {
758                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
759                 if (!config_filename)
760                         config_filename  = git_path("config");
761         }
762         config_filename = xstrdup(config_filename);
763
764         /*
765          * Since "key" actually contains the section name and the real
766          * key name separated by a dot, we have to know where the dot is.
767          */
768
769         if (last_dot == NULL) {
770                 fprintf(stderr, "key does not contain a section: %s\n", key);
771                 ret = 2;
772                 goto out_free;
773         }
774         store.baselen = last_dot - key;
775
776         store.multi_replace = multi_replace;
777
778         /*
779          * Validate the key and while at it, lower case it for matching.
780          */
781         store.key = xmalloc(strlen(key) + 1);
782         dot = 0;
783         for (i = 0; key[i]; i++) {
784                 unsigned char c = key[i];
785                 if (c == '.')
786                         dot = 1;
787                 /* Leave the extended basename untouched.. */
788                 if (!dot || i > store.baselen) {
789                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
790                                 fprintf(stderr, "invalid key: %s\n", key);
791                                 free(store.key);
792                                 ret = 1;
793                                 goto out_free;
794                         }
795                         c = tolower(c);
796                 } else if (c == '\n') {
797                         fprintf(stderr, "invalid key (newline): %s\n", key);
798                         free(store.key);
799                         ret = 1;
800                         goto out_free;
801                 }
802                 store.key[i] = c;
803         }
804         store.key[i] = 0;
805
806         /*
807          * The lock serves a purpose in addition to locking: the new
808          * contents of .git/config will be written into it.
809          */
810         lock = xcalloc(sizeof(struct lock_file), 1);
811         fd = hold_lock_file_for_update(lock, config_filename, 0);
812         if (fd < 0) {
813                 fprintf(stderr, "could not lock config file\n");
814                 free(store.key);
815                 ret = -1;
816                 goto out_free;
817         }
818
819         /*
820          * If .git/config does not exist yet, write a minimal version.
821          */
822         in_fd = open(config_filename, O_RDONLY);
823         if ( in_fd < 0 ) {
824                 free(store.key);
825
826                 if ( ENOENT != errno ) {
827                         error("opening %s: %s", config_filename,
828                               strerror(errno));
829                         ret = 3; /* same as "invalid config file" */
830                         goto out_free;
831                 }
832                 /* if nothing to unset, error out */
833                 if (value == NULL) {
834                         ret = 5;
835                         goto out_free;
836                 }
837
838                 store.key = (char*)key;
839                 if (!store_write_section(fd, key) ||
840                     !store_write_pair(fd, key, value))
841                         goto write_err_out;
842         } else {
843                 struct stat st;
844                 char* contents;
845                 size_t contents_sz, copy_begin, copy_end;
846                 int i, new_line = 0;
847
848                 if (value_regex == NULL)
849                         store.value_regex = NULL;
850                 else {
851                         if (value_regex[0] == '!') {
852                                 store.do_not_match = 1;
853                                 value_regex++;
854                         } else
855                                 store.do_not_match = 0;
856
857                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
858                         if (regcomp(store.value_regex, value_regex,
859                                         REG_EXTENDED)) {
860                                 fprintf(stderr, "Invalid pattern: %s\n",
861                                         value_regex);
862                                 free(store.value_regex);
863                                 ret = 6;
864                                 goto out_free;
865                         }
866                 }
867
868                 store.offset[0] = 0;
869                 store.state = START;
870                 store.seen = 0;
871
872                 /*
873                  * After this, store.offset will contain the *end* offset
874                  * of the last match, or remain at 0 if no match was found.
875                  * As a side effect, we make sure to transform only a valid
876                  * existing config file.
877                  */
878                 if (git_config_from_file(store_aux, config_filename)) {
879                         fprintf(stderr, "invalid config file\n");
880                         free(store.key);
881                         if (store.value_regex != NULL) {
882                                 regfree(store.value_regex);
883                                 free(store.value_regex);
884                         }
885                         ret = 3;
886                         goto out_free;
887                 }
888
889                 free(store.key);
890                 if (store.value_regex != NULL) {
891                         regfree(store.value_regex);
892                         free(store.value_regex);
893                 }
894
895                 /* if nothing to unset, or too many matches, error out */
896                 if ((store.seen == 0 && value == NULL) ||
897                                 (store.seen > 1 && multi_replace == 0)) {
898                         ret = 5;
899                         goto out_free;
900                 }
901
902                 fstat(in_fd, &st);
903                 contents_sz = xsize_t(st.st_size);
904                 contents = xmmap(NULL, contents_sz, PROT_READ,
905                         MAP_PRIVATE, in_fd, 0);
906                 close(in_fd);
907
908                 if (store.seen == 0)
909                         store.seen = 1;
910
911                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
912                         if (store.offset[i] == 0) {
913                                 store.offset[i] = copy_end = contents_sz;
914                         } else if (store.state != KEY_SEEN) {
915                                 copy_end = store.offset[i];
916                         } else
917                                 copy_end = find_beginning_of_line(
918                                         contents, contents_sz,
919                                         store.offset[i]-2, &new_line);
920
921                         /* write the first part of the config */
922                         if (copy_end > copy_begin) {
923                                 if (write_in_full(fd, contents + copy_begin,
924                                                   copy_end - copy_begin) <
925                                     copy_end - copy_begin)
926                                         goto write_err_out;
927                                 if (new_line &&
928                                     write_in_full(fd, "\n", 1) != 1)
929                                         goto write_err_out;
930                         }
931                         copy_begin = store.offset[i];
932                 }
933
934                 /* write the pair (value == NULL means unset) */
935                 if (value != NULL) {
936                         if (store.state == START) {
937                                 if (!store_write_section(fd, key))
938                                         goto write_err_out;
939                         }
940                         if (!store_write_pair(fd, key, value))
941                                 goto write_err_out;
942                 }
943
944                 /* write the rest of the config */
945                 if (copy_begin < contents_sz)
946                         if (write_in_full(fd, contents + copy_begin,
947                                           contents_sz - copy_begin) <
948                             contents_sz - copy_begin)
949                                 goto write_err_out;
950
951                 munmap(contents, contents_sz);
952         }
953
954         if (close(fd) || commit_lock_file(lock) < 0) {
955                 fprintf(stderr, "Cannot commit config file!\n");
956                 ret = 4;
957                 goto out_free;
958         }
959
960         /* fd is closed, so don't try to close it below. */
961         fd = -1;
962         /*
963          * lock is committed, so don't try to roll it back below.
964          * NOTE: Since lockfile.c keeps a linked list of all created
965          * lock_file structures, it isn't safe to free(lock).  It's
966          * better to just leave it hanging around.
967          */
968         lock = NULL;
969         ret = 0;
970
971 out_free:
972         if (0 <= fd)
973                 close(fd);
974         if (lock)
975                 rollback_lock_file(lock);
976         free(config_filename);
977         return ret;
978
979 write_err_out:
980         ret = write_error();
981         goto out_free;
982
983 }
984
985 static int section_name_match (const char *buf, const char *name)
986 {
987         int i = 0, j = 0, dot = 0;
988         for (; buf[i] && buf[i] != ']'; i++) {
989                 if (!dot && isspace(buf[i])) {
990                         dot = 1;
991                         if (name[j++] != '.')
992                                 break;
993                         for (i++; isspace(buf[i]); i++)
994                                 ; /* do nothing */
995                         if (buf[i] != '"')
996                                 break;
997                         continue;
998                 }
999                 if (buf[i] == '\\' && dot)
1000                         i++;
1001                 else if (buf[i] == '"' && dot) {
1002                         for (i++; isspace(buf[i]); i++)
1003                                 ; /* do_nothing */
1004                         break;
1005                 }
1006                 if (buf[i] != name[j++])
1007                         break;
1008         }
1009         return (buf[i] == ']' && name[j] == 0);
1010 }
1011
1012 /* if new_name == NULL, the section is removed instead */
1013 int git_config_rename_section(const char *old_name, const char *new_name)
1014 {
1015         int ret = 0, remove = 0;
1016         char *config_filename;
1017         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1018         int out_fd;
1019         char buf[1024];
1020
1021         config_filename = getenv(CONFIG_ENVIRONMENT);
1022         if (!config_filename) {
1023                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1024                 if (!config_filename)
1025                         config_filename  = git_path("config");
1026         }
1027         config_filename = xstrdup(config_filename);
1028         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1029         if (out_fd < 0) {
1030                 ret = error("Could not lock config file!");
1031                 goto out;
1032         }
1033
1034         if (!(config_file = fopen(config_filename, "rb"))) {
1035                 /* no config file means nothing to rename, no error */
1036                 goto unlock_and_out;
1037         }
1038
1039         while (fgets(buf, sizeof(buf), config_file)) {
1040                 int i;
1041                 int length;
1042                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1043                         ; /* do nothing */
1044                 if (buf[i] == '[') {
1045                         /* it's a section */
1046                         if (section_name_match (&buf[i+1], old_name)) {
1047                                 ret++;
1048                                 if (new_name == NULL) {
1049                                         remove = 1;
1050                                         continue;
1051                                 }
1052                                 store.baselen = strlen(new_name);
1053                                 if (!store_write_section(out_fd, new_name)) {
1054                                         ret = write_error();
1055                                         goto out;
1056                                 }
1057                                 continue;
1058                         }
1059                         remove = 0;
1060                 }
1061                 if (remove)
1062                         continue;
1063                 length = strlen(buf);
1064                 if (write_in_full(out_fd, buf, length) != length) {
1065                         ret = write_error();
1066                         goto out;
1067                 }
1068         }
1069         fclose(config_file);
1070  unlock_and_out:
1071         if (close(out_fd) || commit_lock_file(lock) < 0)
1072                         ret = error("Cannot commit config file!");
1073  out:
1074         free(config_filename);
1075         return ret;
1076 }