config: add 'git_config_string' to refactor string config variables.
[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 config_file_eof;
17 static int zlib_compression_seen;
18
19 static int get_next_char(void)
20 {
21         int c;
22         FILE *f;
23
24         c = '\n';
25         if ((f = config_file) != NULL) {
26                 c = fgetc(f);
27                 if (c == '\r') {
28                         /* DOS like systems */
29                         c = fgetc(f);
30                         if (c != '\n') {
31                                 ungetc(c, f);
32                                 c = '\r';
33                         }
34                 }
35                 if (c == '\n')
36                         config_linenr++;
37                 if (c == EOF) {
38                         config_file_eof = 1;
39                         c = '\n';
40                 }
41         }
42         return c;
43 }
44
45 static char *parse_value(void)
46 {
47         static char value[1024];
48         int quote = 0, comment = 0, len = 0, space = 0;
49
50         for (;;) {
51                 int c = get_next_char();
52                 if (len >= sizeof(value))
53                         return NULL;
54                 if (c == '\n') {
55                         if (quote)
56                                 return NULL;
57                         value[len] = 0;
58                         return value;
59                 }
60                 if (comment)
61                         continue;
62                 if (isspace(c) && !quote) {
63                         space = 1;
64                         continue;
65                 }
66                 if (!quote) {
67                         if (c == ';' || c == '#') {
68                                 comment = 1;
69                                 continue;
70                         }
71                 }
72                 if (space) {
73                         if (len)
74                                 value[len++] = ' ';
75                         space = 0;
76                 }
77                 if (c == '\\') {
78                         c = get_next_char();
79                         switch (c) {
80                         case '\n':
81                                 continue;
82                         case 't':
83                                 c = '\t';
84                                 break;
85                         case 'b':
86                                 c = '\b';
87                                 break;
88                         case 'n':
89                                 c = '\n';
90                                 break;
91                         /* Some characters escape as themselves */
92                         case '\\': case '"':
93                                 break;
94                         /* Reject unknown escape sequences */
95                         default:
96                                 return NULL;
97                         }
98                         value[len++] = c;
99                         continue;
100                 }
101                 if (c == '"') {
102                         quote = 1-quote;
103                         continue;
104                 }
105                 value[len++] = c;
106         }
107 }
108
109 static inline int iskeychar(int c)
110 {
111         return isalnum(c) || c == '-';
112 }
113
114 static int get_value(config_fn_t fn, char *name, unsigned int len)
115 {
116         int c;
117         char *value;
118
119         /* Get the full name */
120         for (;;) {
121                 c = get_next_char();
122                 if (config_file_eof)
123                         break;
124                 if (!iskeychar(c))
125                         break;
126                 name[len++] = tolower(c);
127                 if (len >= MAXNAME)
128                         return -1;
129         }
130         name[len] = 0;
131         while (c == ' ' || c == '\t')
132                 c = get_next_char();
133
134         value = NULL;
135         if (c != '\n') {
136                 if (c != '=')
137                         return -1;
138                 value = parse_value();
139                 if (!value)
140                         return -1;
141         }
142         return fn(name, value);
143 }
144
145 static int get_extended_base_var(char *name, int baselen, int c)
146 {
147         do {
148                 if (c == '\n')
149                         return -1;
150                 c = get_next_char();
151         } while (isspace(c));
152
153         /* We require the format to be '[base "extension"]' */
154         if (c != '"')
155                 return -1;
156         name[baselen++] = '.';
157
158         for (;;) {
159                 int c = get_next_char();
160                 if (c == '\n')
161                         return -1;
162                 if (c == '"')
163                         break;
164                 if (c == '\\') {
165                         c = get_next_char();
166                         if (c == '\n')
167                                 return -1;
168                 }
169                 name[baselen++] = c;
170                 if (baselen > MAXNAME / 2)
171                         return -1;
172         }
173
174         /* Final ']' */
175         if (get_next_char() != ']')
176                 return -1;
177         return baselen;
178 }
179
180 static int get_base_var(char *name)
181 {
182         int baselen = 0;
183
184         for (;;) {
185                 int c = get_next_char();
186                 if (config_file_eof)
187                         return -1;
188                 if (c == ']')
189                         return baselen;
190                 if (isspace(c))
191                         return get_extended_base_var(name, baselen, c);
192                 if (!iskeychar(c) && c != '.')
193                         return -1;
194                 if (baselen > MAXNAME / 2)
195                         return -1;
196                 name[baselen++] = tolower(c);
197         }
198 }
199
200 static int git_parse_file(config_fn_t fn)
201 {
202         int comment = 0;
203         int baselen = 0;
204         static char var[MAXNAME];
205
206         for (;;) {
207                 int c = get_next_char();
208                 if (c == '\n') {
209                         if (config_file_eof)
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_config_string(const char **dest, const char *var, const char *value)
313 {
314         if (!value)
315                 return config_error_nonbool(var);
316         *dest = xstrdup(value);
317         return 0;
318 }
319
320 int git_default_config(const char *var, const char *value)
321 {
322         /* This needs a better name */
323         if (!strcmp(var, "core.filemode")) {
324                 trust_executable_bit = git_config_bool(var, value);
325                 return 0;
326         }
327
328         if (!strcmp(var, "core.quotepath")) {
329                 quote_path_fully = git_config_bool(var, value);
330                 return 0;
331         }
332
333         if (!strcmp(var, "core.symlinks")) {
334                 has_symlinks = git_config_bool(var, value);
335                 return 0;
336         }
337
338         if (!strcmp(var, "core.bare")) {
339                 is_bare_repository_cfg = git_config_bool(var, value);
340                 return 0;
341         }
342
343         if (!strcmp(var, "core.ignorestat")) {
344                 assume_unchanged = git_config_bool(var, value);
345                 return 0;
346         }
347
348         if (!strcmp(var, "core.prefersymlinkrefs")) {
349                 prefer_symlink_refs = git_config_bool(var, value);
350                 return 0;
351         }
352
353         if (!strcmp(var, "core.logallrefupdates")) {
354                 log_all_ref_updates = git_config_bool(var, value);
355                 return 0;
356         }
357
358         if (!strcmp(var, "core.warnambiguousrefs")) {
359                 warn_ambiguous_refs = git_config_bool(var, value);
360                 return 0;
361         }
362
363         if (!strcmp(var, "core.loosecompression")) {
364                 int level = git_config_int(var, value);
365                 if (level == -1)
366                         level = Z_DEFAULT_COMPRESSION;
367                 else if (level < 0 || level > Z_BEST_COMPRESSION)
368                         die("bad zlib compression level %d", level);
369                 zlib_compression_level = level;
370                 zlib_compression_seen = 1;
371                 return 0;
372         }
373
374         if (!strcmp(var, "core.compression")) {
375                 int level = git_config_int(var, value);
376                 if (level == -1)
377                         level = Z_DEFAULT_COMPRESSION;
378                 else if (level < 0 || level > Z_BEST_COMPRESSION)
379                         die("bad zlib compression level %d", level);
380                 core_compression_level = level;
381                 core_compression_seen = 1;
382                 if (!zlib_compression_seen)
383                         zlib_compression_level = level;
384                 return 0;
385         }
386
387         if (!strcmp(var, "core.packedgitwindowsize")) {
388                 int pgsz_x2 = getpagesize() * 2;
389                 packed_git_window_size = git_config_int(var, value);
390
391                 /* This value must be multiple of (pagesize * 2) */
392                 packed_git_window_size /= pgsz_x2;
393                 if (packed_git_window_size < 1)
394                         packed_git_window_size = 1;
395                 packed_git_window_size *= pgsz_x2;
396                 return 0;
397         }
398
399         if (!strcmp(var, "core.packedgitlimit")) {
400                 packed_git_limit = git_config_int(var, value);
401                 return 0;
402         }
403
404         if (!strcmp(var, "core.deltabasecachelimit")) {
405                 delta_base_cache_limit = git_config_int(var, value);
406                 return 0;
407         }
408
409         if (!strcmp(var, "core.autocrlf")) {
410                 if (value && !strcasecmp(value, "input")) {
411                         auto_crlf = -1;
412                         return 0;
413                 }
414                 auto_crlf = git_config_bool(var, value);
415                 return 0;
416         }
417
418         if (!strcmp(var, "user.name")) {
419                 if (!value)
420                         return config_error_nonbool(var);
421                 strlcpy(git_default_name, value, sizeof(git_default_name));
422                 return 0;
423         }
424
425         if (!strcmp(var, "user.email")) {
426                 if (!value)
427                         return config_error_nonbool(var);
428                 strlcpy(git_default_email, value, sizeof(git_default_email));
429                 return 0;
430         }
431
432         if (!strcmp(var, "i18n.commitencoding"))
433                 return git_config_string(&git_commit_encoding, var, value);
434
435         if (!strcmp(var, "i18n.logoutputencoding"))
436                 return git_config_string(&git_log_output_encoding, var, value);
437
438         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
439                 pager_use_color = git_config_bool(var,value);
440                 return 0;
441         }
442
443         if (!strcmp(var, "core.pager")) {
444                 if (!value)
445                         return config_error_nonbool(var);
446                 pager_program = xstrdup(value);
447                 return 0;
448         }
449
450         if (!strcmp(var, "core.editor")) {
451                 if (!value)
452                         return config_error_nonbool(var);
453                 editor_program = xstrdup(value);
454                 return 0;
455         }
456
457         if (!strcmp(var, "core.excludesfile")) {
458                 if (!value)
459                         return config_error_nonbool(var);
460                 excludes_file = xstrdup(value);
461                 return 0;
462         }
463
464         if (!strcmp(var, "core.whitespace")) {
465                 if (!value)
466                         return config_error_nonbool(var);
467                 whitespace_rule_cfg = parse_whitespace_rule(value);
468                 return 0;
469         }
470
471         /* Add other config variables here and to Documentation/config.txt. */
472         return 0;
473 }
474
475 int git_config_from_file(config_fn_t fn, const char *filename)
476 {
477         int ret;
478         FILE *f = fopen(filename, "r");
479
480         ret = -1;
481         if (f) {
482                 config_file = f;
483                 config_file_name = filename;
484                 config_linenr = 1;
485                 config_file_eof = 0;
486                 ret = git_parse_file(fn);
487                 fclose(f);
488                 config_file_name = NULL;
489         }
490         return ret;
491 }
492
493 const char *git_etc_gitconfig(void)
494 {
495         static const char *system_wide;
496         if (!system_wide) {
497                 system_wide = ETC_GITCONFIG;
498                 if (!is_absolute_path(system_wide)) {
499                         /* interpret path relative to exec-dir */
500                         const char *exec_path = git_exec_path();
501                         system_wide = prefix_path(exec_path, strlen(exec_path),
502                                                 system_wide);
503                 }
504         }
505         return system_wide;
506 }
507
508 int git_config(config_fn_t fn)
509 {
510         int ret = 0;
511         char *repo_config = NULL;
512         const char *home = NULL, *filename;
513
514         /* $GIT_CONFIG makes git read _only_ the given config file,
515          * $GIT_CONFIG_LOCAL will make it process it in addition to the
516          * global config file, the same way it would the per-repository
517          * config file otherwise. */
518         filename = getenv(CONFIG_ENVIRONMENT);
519         if (!filename) {
520                 if (!access(git_etc_gitconfig(), R_OK))
521                         ret += git_config_from_file(fn, git_etc_gitconfig());
522                 home = getenv("HOME");
523                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
524                 if (!filename)
525                         filename = repo_config = xstrdup(git_path("config"));
526         }
527
528         if (home) {
529                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
530                 if (!access(user_config, R_OK))
531                         ret = git_config_from_file(fn, user_config);
532                 free(user_config);
533         }
534
535         ret += git_config_from_file(fn, filename);
536         free(repo_config);
537         return ret;
538 }
539
540 /*
541  * Find all the stuff for git_config_set() below.
542  */
543
544 #define MAX_MATCHES 512
545
546 static struct {
547         int baselen;
548         char* key;
549         int do_not_match;
550         regex_t* value_regex;
551         int multi_replace;
552         size_t offset[MAX_MATCHES];
553         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
554         int seen;
555 } store;
556
557 static int matches(const char* key, const char* value)
558 {
559         return !strcmp(key, store.key) &&
560                 (store.value_regex == NULL ||
561                  (store.do_not_match ^
562                   !regexec(store.value_regex, value, 0, NULL, 0)));
563 }
564
565 static int store_aux(const char* key, const char* value)
566 {
567         const char *ep;
568         size_t section_len;
569
570         switch (store.state) {
571         case KEY_SEEN:
572                 if (matches(key, value)) {
573                         if (store.seen == 1 && store.multi_replace == 0) {
574                                 fprintf(stderr,
575                                         "Warning: %s has multiple values\n",
576                                         key);
577                         } else if (store.seen >= MAX_MATCHES) {
578                                 fprintf(stderr, "Too many matches\n");
579                                 return 1;
580                         }
581
582                         store.offset[store.seen] = ftell(config_file);
583                         store.seen++;
584                 }
585                 break;
586         case SECTION_SEEN:
587                 /*
588                  * What we are looking for is in store.key (both
589                  * section and var), and its section part is baselen
590                  * long.  We found key (again, both section and var).
591                  * We would want to know if this key is in the same
592                  * section as what we are looking for.  We already
593                  * know we are in the same section as what should
594                  * hold store.key.
595                  */
596                 ep = strrchr(key, '.');
597                 section_len = ep - key;
598
599                 if ((section_len != store.baselen) ||
600                     memcmp(key, store.key, section_len+1)) {
601                         store.state = SECTION_END_SEEN;
602                         break;
603                 }
604
605                 /*
606                  * Do not increment matches: this is no match, but we
607                  * just made sure we are in the desired section.
608                  */
609                 store.offset[store.seen] = ftell(config_file);
610                 /* fallthru */
611         case SECTION_END_SEEN:
612         case START:
613                 if (matches(key, value)) {
614                         store.offset[store.seen] = ftell(config_file);
615                         store.state = KEY_SEEN;
616                         store.seen++;
617                 } else {
618                         if (strrchr(key, '.') - key == store.baselen &&
619                               !strncmp(key, store.key, store.baselen)) {
620                                         store.state = SECTION_SEEN;
621                                         store.offset[store.seen] = ftell(config_file);
622                         }
623                 }
624         }
625         return 0;
626 }
627
628 static int write_error(void)
629 {
630         fprintf(stderr, "Failed to write new configuration file\n");
631
632         /* Same error code as "failed to rename". */
633         return 4;
634 }
635
636 static int store_write_section(int fd, const char* key)
637 {
638         const char *dot;
639         int i, success;
640         struct strbuf sb;
641
642         strbuf_init(&sb, 0);
643         dot = memchr(key, '.', store.baselen);
644         if (dot) {
645                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
646                 for (i = dot - key + 1; i < store.baselen; i++) {
647                         if (key[i] == '"')
648                                 strbuf_addch(&sb, '\\');
649                         strbuf_addch(&sb, key[i]);
650                 }
651                 strbuf_addstr(&sb, "\"]\n");
652         } else {
653                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
654         }
655
656         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
657         strbuf_release(&sb);
658
659         return success;
660 }
661
662 static int store_write_pair(int fd, const char* key, const char* value)
663 {
664         int i, success;
665         int length = strlen(key + store.baselen + 1);
666         const char *quote = "";
667         struct strbuf sb;
668
669         /*
670          * Check to see if the value needs to be surrounded with a dq pair.
671          * Note that problematic characters are always backslash-quoted; this
672          * check is about not losing leading or trailing SP and strings that
673          * follow beginning-of-comment characters (i.e. ';' and '#') by the
674          * configuration parser.
675          */
676         if (value[0] == ' ')
677                 quote = "\"";
678         for (i = 0; value[i]; i++)
679                 if (value[i] == ';' || value[i] == '#')
680                         quote = "\"";
681         if (i && value[i - 1] == ' ')
682                 quote = "\"";
683
684         strbuf_init(&sb, 0);
685         strbuf_addf(&sb, "\t%.*s = %s",
686                     length, key + store.baselen + 1, quote);
687
688         for (i = 0; value[i]; i++)
689                 switch (value[i]) {
690                 case '\n':
691                         strbuf_addstr(&sb, "\\n");
692                         break;
693                 case '\t':
694                         strbuf_addstr(&sb, "\\t");
695                         break;
696                 case '"':
697                 case '\\':
698                         strbuf_addch(&sb, '\\');
699                 default:
700                         strbuf_addch(&sb, value[i]);
701                         break;
702                 }
703         strbuf_addf(&sb, "%s\n", quote);
704
705         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
706         strbuf_release(&sb);
707
708         return success;
709 }
710
711 static ssize_t find_beginning_of_line(const char* contents, size_t size,
712         size_t offset_, int* found_bracket)
713 {
714         size_t equal_offset = size, bracket_offset = size;
715         ssize_t offset;
716
717 contline:
718         for (offset = offset_-2; offset > 0
719                         && contents[offset] != '\n'; offset--)
720                 switch (contents[offset]) {
721                         case '=': equal_offset = offset; break;
722                         case ']': bracket_offset = offset; break;
723                 }
724         if (offset > 0 && contents[offset-1] == '\\') {
725                 offset_ = offset;
726                 goto contline;
727         }
728         if (bracket_offset < equal_offset) {
729                 *found_bracket = 1;
730                 offset = bracket_offset+1;
731         } else
732                 offset++;
733
734         return offset;
735 }
736
737 int git_config_set(const char* key, const char* value)
738 {
739         return git_config_set_multivar(key, value, NULL, 0);
740 }
741
742 /*
743  * If value==NULL, unset in (remove from) config,
744  * if value_regex!=NULL, disregard key/value pairs where value does not match.
745  * if multi_replace==0, nothing, or only one matching key/value is replaced,
746  *     else all matching key/values (regardless how many) are removed,
747  *     before the new pair is written.
748  *
749  * Returns 0 on success.
750  *
751  * This function does this:
752  *
753  * - it locks the config file by creating ".git/config.lock"
754  *
755  * - it then parses the config using store_aux() as validator to find
756  *   the position on the key/value pair to replace. If it is to be unset,
757  *   it must be found exactly once.
758  *
759  * - the config file is mmap()ed and the part before the match (if any) is
760  *   written to the lock file, then the changed part and the rest.
761  *
762  * - the config file is removed and the lock file rename()d to it.
763  *
764  */
765 int git_config_set_multivar(const char* key, const char* value,
766         const char* value_regex, int multi_replace)
767 {
768         int i, dot;
769         int fd = -1, in_fd;
770         int ret;
771         char* config_filename;
772         struct lock_file *lock = NULL;
773         const char* last_dot = strrchr(key, '.');
774
775         config_filename = getenv(CONFIG_ENVIRONMENT);
776         if (!config_filename) {
777                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
778                 if (!config_filename)
779                         config_filename  = git_path("config");
780         }
781         config_filename = xstrdup(config_filename);
782
783         /*
784          * Since "key" actually contains the section name and the real
785          * key name separated by a dot, we have to know where the dot is.
786          */
787
788         if (last_dot == NULL) {
789                 fprintf(stderr, "key does not contain a section: %s\n", key);
790                 ret = 2;
791                 goto out_free;
792         }
793         store.baselen = last_dot - key;
794
795         store.multi_replace = multi_replace;
796
797         /*
798          * Validate the key and while at it, lower case it for matching.
799          */
800         store.key = xmalloc(strlen(key) + 1);
801         dot = 0;
802         for (i = 0; key[i]; i++) {
803                 unsigned char c = key[i];
804                 if (c == '.')
805                         dot = 1;
806                 /* Leave the extended basename untouched.. */
807                 if (!dot || i > store.baselen) {
808                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
809                                 fprintf(stderr, "invalid key: %s\n", key);
810                                 free(store.key);
811                                 ret = 1;
812                                 goto out_free;
813                         }
814                         c = tolower(c);
815                 } else if (c == '\n') {
816                         fprintf(stderr, "invalid key (newline): %s\n", key);
817                         free(store.key);
818                         ret = 1;
819                         goto out_free;
820                 }
821                 store.key[i] = c;
822         }
823         store.key[i] = 0;
824
825         /*
826          * The lock serves a purpose in addition to locking: the new
827          * contents of .git/config will be written into it.
828          */
829         lock = xcalloc(sizeof(struct lock_file), 1);
830         fd = hold_lock_file_for_update(lock, config_filename, 0);
831         if (fd < 0) {
832                 fprintf(stderr, "could not lock config file\n");
833                 free(store.key);
834                 ret = -1;
835                 goto out_free;
836         }
837
838         /*
839          * If .git/config does not exist yet, write a minimal version.
840          */
841         in_fd = open(config_filename, O_RDONLY);
842         if ( in_fd < 0 ) {
843                 free(store.key);
844
845                 if ( ENOENT != errno ) {
846                         error("opening %s: %s", config_filename,
847                               strerror(errno));
848                         ret = 3; /* same as "invalid config file" */
849                         goto out_free;
850                 }
851                 /* if nothing to unset, error out */
852                 if (value == NULL) {
853                         ret = 5;
854                         goto out_free;
855                 }
856
857                 store.key = (char*)key;
858                 if (!store_write_section(fd, key) ||
859                     !store_write_pair(fd, key, value))
860                         goto write_err_out;
861         } else {
862                 struct stat st;
863                 char* contents;
864                 size_t contents_sz, copy_begin, copy_end;
865                 int i, new_line = 0;
866
867                 if (value_regex == NULL)
868                         store.value_regex = NULL;
869                 else {
870                         if (value_regex[0] == '!') {
871                                 store.do_not_match = 1;
872                                 value_regex++;
873                         } else
874                                 store.do_not_match = 0;
875
876                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
877                         if (regcomp(store.value_regex, value_regex,
878                                         REG_EXTENDED)) {
879                                 fprintf(stderr, "Invalid pattern: %s\n",
880                                         value_regex);
881                                 free(store.value_regex);
882                                 ret = 6;
883                                 goto out_free;
884                         }
885                 }
886
887                 store.offset[0] = 0;
888                 store.state = START;
889                 store.seen = 0;
890
891                 /*
892                  * After this, store.offset will contain the *end* offset
893                  * of the last match, or remain at 0 if no match was found.
894                  * As a side effect, we make sure to transform only a valid
895                  * existing config file.
896                  */
897                 if (git_config_from_file(store_aux, config_filename)) {
898                         fprintf(stderr, "invalid config file\n");
899                         free(store.key);
900                         if (store.value_regex != NULL) {
901                                 regfree(store.value_regex);
902                                 free(store.value_regex);
903                         }
904                         ret = 3;
905                         goto out_free;
906                 }
907
908                 free(store.key);
909                 if (store.value_regex != NULL) {
910                         regfree(store.value_regex);
911                         free(store.value_regex);
912                 }
913
914                 /* if nothing to unset, or too many matches, error out */
915                 if ((store.seen == 0 && value == NULL) ||
916                                 (store.seen > 1 && multi_replace == 0)) {
917                         ret = 5;
918                         goto out_free;
919                 }
920
921                 fstat(in_fd, &st);
922                 contents_sz = xsize_t(st.st_size);
923                 contents = xmmap(NULL, contents_sz, PROT_READ,
924                         MAP_PRIVATE, in_fd, 0);
925                 close(in_fd);
926
927                 if (store.seen == 0)
928                         store.seen = 1;
929
930                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
931                         if (store.offset[i] == 0) {
932                                 store.offset[i] = copy_end = contents_sz;
933                         } else if (store.state != KEY_SEEN) {
934                                 copy_end = store.offset[i];
935                         } else
936                                 copy_end = find_beginning_of_line(
937                                         contents, contents_sz,
938                                         store.offset[i]-2, &new_line);
939
940                         if (copy_end > 0 && contents[copy_end-1] != '\n')
941                                 new_line = 1;
942
943                         /* write the first part of the config */
944                         if (copy_end > copy_begin) {
945                                 if (write_in_full(fd, contents + copy_begin,
946                                                   copy_end - copy_begin) <
947                                     copy_end - copy_begin)
948                                         goto write_err_out;
949                                 if (new_line &&
950                                     write_in_full(fd, "\n", 1) != 1)
951                                         goto write_err_out;
952                         }
953                         copy_begin = store.offset[i];
954                 }
955
956                 /* write the pair (value == NULL means unset) */
957                 if (value != NULL) {
958                         if (store.state == START) {
959                                 if (!store_write_section(fd, key))
960                                         goto write_err_out;
961                         }
962                         if (!store_write_pair(fd, key, value))
963                                 goto write_err_out;
964                 }
965
966                 /* write the rest of the config */
967                 if (copy_begin < contents_sz)
968                         if (write_in_full(fd, contents + copy_begin,
969                                           contents_sz - copy_begin) <
970                             contents_sz - copy_begin)
971                                 goto write_err_out;
972
973                 munmap(contents, contents_sz);
974         }
975
976         if (commit_lock_file(lock) < 0) {
977                 fprintf(stderr, "Cannot commit config file!\n");
978                 ret = 4;
979                 goto out_free;
980         }
981
982         /*
983          * lock is committed, so don't try to roll it back below.
984          * NOTE: Since lockfile.c keeps a linked list of all created
985          * lock_file structures, it isn't safe to free(lock).  It's
986          * better to just leave it hanging around.
987          */
988         lock = NULL;
989         ret = 0;
990
991 out_free:
992         if (lock)
993                 rollback_lock_file(lock);
994         free(config_filename);
995         return ret;
996
997 write_err_out:
998         ret = write_error();
999         goto out_free;
1000
1001 }
1002
1003 static int section_name_match (const char *buf, const char *name)
1004 {
1005         int i = 0, j = 0, dot = 0;
1006         for (; buf[i] && buf[i] != ']'; i++) {
1007                 if (!dot && isspace(buf[i])) {
1008                         dot = 1;
1009                         if (name[j++] != '.')
1010                                 break;
1011                         for (i++; isspace(buf[i]); i++)
1012                                 ; /* do nothing */
1013                         if (buf[i] != '"')
1014                                 break;
1015                         continue;
1016                 }
1017                 if (buf[i] == '\\' && dot)
1018                         i++;
1019                 else if (buf[i] == '"' && dot) {
1020                         for (i++; isspace(buf[i]); i++)
1021                                 ; /* do_nothing */
1022                         break;
1023                 }
1024                 if (buf[i] != name[j++])
1025                         break;
1026         }
1027         return (buf[i] == ']' && name[j] == 0);
1028 }
1029
1030 /* if new_name == NULL, the section is removed instead */
1031 int git_config_rename_section(const char *old_name, const char *new_name)
1032 {
1033         int ret = 0, remove = 0;
1034         char *config_filename;
1035         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1036         int out_fd;
1037         char buf[1024];
1038
1039         config_filename = getenv(CONFIG_ENVIRONMENT);
1040         if (!config_filename) {
1041                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1042                 if (!config_filename)
1043                         config_filename  = git_path("config");
1044         }
1045         config_filename = xstrdup(config_filename);
1046         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1047         if (out_fd < 0) {
1048                 ret = error("Could not lock config file!");
1049                 goto out;
1050         }
1051
1052         if (!(config_file = fopen(config_filename, "rb"))) {
1053                 /* no config file means nothing to rename, no error */
1054                 goto unlock_and_out;
1055         }
1056
1057         while (fgets(buf, sizeof(buf), config_file)) {
1058                 int i;
1059                 int length;
1060                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1061                         ; /* do nothing */
1062                 if (buf[i] == '[') {
1063                         /* it's a section */
1064                         if (section_name_match (&buf[i+1], old_name)) {
1065                                 ret++;
1066                                 if (new_name == NULL) {
1067                                         remove = 1;
1068                                         continue;
1069                                 }
1070                                 store.baselen = strlen(new_name);
1071                                 if (!store_write_section(out_fd, new_name)) {
1072                                         ret = write_error();
1073                                         goto out;
1074                                 }
1075                                 continue;
1076                         }
1077                         remove = 0;
1078                 }
1079                 if (remove)
1080                         continue;
1081                 length = strlen(buf);
1082                 if (write_in_full(out_fd, buf, length) != length) {
1083                         ret = write_error();
1084                         goto out;
1085                 }
1086         }
1087         fclose(config_file);
1088  unlock_and_out:
1089         if (commit_lock_file(lock) < 0)
1090                         ret = error("Cannot commit config file!");
1091  out:
1092         free(config_filename);
1093         return ret;
1094 }
1095
1096 /*
1097  * Call this to report error for your variable that should not
1098  * get a boolean value (i.e. "[my] var" means "true").
1099  */
1100 int config_error_nonbool(const char *var)
1101 {
1102         return error("Missing value for '%s'", var);
1103 }