config: add test cases for empty value and no value 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_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                 config_file_eof = 0;
473                 ret = git_parse_file(fn);
474                 fclose(f);
475                 config_file_name = NULL;
476         }
477         return ret;
478 }
479
480 const char *git_etc_gitconfig(void)
481 {
482         static const char *system_wide;
483         if (!system_wide) {
484                 system_wide = ETC_GITCONFIG;
485                 if (!is_absolute_path(system_wide)) {
486                         /* interpret path relative to exec-dir */
487                         struct strbuf d = STRBUF_INIT;
488                         strbuf_addf(&d, "%s/%s", git_exec_path(), system_wide);
489                         system_wide = strbuf_detach(&d, NULL);
490                 }
491         }
492         return system_wide;
493 }
494
495 int git_config(config_fn_t fn)
496 {
497         int ret = 0;
498         char *repo_config = NULL;
499         const char *home = NULL, *filename;
500
501         /* $GIT_CONFIG makes git read _only_ the given config file,
502          * $GIT_CONFIG_LOCAL will make it process it in addition to the
503          * global config file, the same way it would the per-repository
504          * config file otherwise. */
505         filename = getenv(CONFIG_ENVIRONMENT);
506         if (!filename) {
507                 if (!access(git_etc_gitconfig(), R_OK))
508                         ret += git_config_from_file(fn, git_etc_gitconfig());
509                 home = getenv("HOME");
510                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
511                 if (!filename)
512                         filename = repo_config = xstrdup(git_path("config"));
513         }
514
515         if (home) {
516                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
517                 if (!access(user_config, R_OK))
518                         ret = git_config_from_file(fn, user_config);
519                 free(user_config);
520         }
521
522         ret += git_config_from_file(fn, filename);
523         free(repo_config);
524         return ret;
525 }
526
527 /*
528  * Find all the stuff for git_config_set() below.
529  */
530
531 #define MAX_MATCHES 512
532
533 static struct {
534         int baselen;
535         char* key;
536         int do_not_match;
537         regex_t* value_regex;
538         int multi_replace;
539         size_t offset[MAX_MATCHES];
540         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
541         int seen;
542 } store;
543
544 static int matches(const char* key, const char* value)
545 {
546         return !strcmp(key, store.key) &&
547                 (store.value_regex == NULL ||
548                  (store.do_not_match ^
549                   !regexec(store.value_regex, value, 0, NULL, 0)));
550 }
551
552 static int store_aux(const char* key, const char* value)
553 {
554         const char *ep;
555         size_t section_len;
556
557         switch (store.state) {
558         case KEY_SEEN:
559                 if (matches(key, value)) {
560                         if (store.seen == 1 && store.multi_replace == 0) {
561                                 fprintf(stderr,
562                                         "Warning: %s has multiple values\n",
563                                         key);
564                         } else if (store.seen >= MAX_MATCHES) {
565                                 fprintf(stderr, "Too many matches\n");
566                                 return 1;
567                         }
568
569                         store.offset[store.seen] = ftell(config_file);
570                         store.seen++;
571                 }
572                 break;
573         case SECTION_SEEN:
574                 /*
575                  * What we are looking for is in store.key (both
576                  * section and var), and its section part is baselen
577                  * long.  We found key (again, both section and var).
578                  * We would want to know if this key is in the same
579                  * section as what we are looking for.  We already
580                  * know we are in the same section as what should
581                  * hold store.key.
582                  */
583                 ep = strrchr(key, '.');
584                 section_len = ep - key;
585
586                 if ((section_len != store.baselen) ||
587                     memcmp(key, store.key, section_len+1)) {
588                         store.state = SECTION_END_SEEN;
589                         break;
590                 }
591
592                 /*
593                  * Do not increment matches: this is no match, but we
594                  * just made sure we are in the desired section.
595                  */
596                 store.offset[store.seen] = ftell(config_file);
597                 /* fallthru */
598         case SECTION_END_SEEN:
599         case START:
600                 if (matches(key, value)) {
601                         store.offset[store.seen] = ftell(config_file);
602                         store.state = KEY_SEEN;
603                         store.seen++;
604                 } else {
605                         if (strrchr(key, '.') - key == store.baselen &&
606                               !strncmp(key, store.key, store.baselen)) {
607                                         store.state = SECTION_SEEN;
608                                         store.offset[store.seen] = ftell(config_file);
609                         }
610                 }
611         }
612         return 0;
613 }
614
615 static int write_error(void)
616 {
617         fprintf(stderr, "Failed to write new configuration file\n");
618
619         /* Same error code as "failed to rename". */
620         return 4;
621 }
622
623 static int store_write_section(int fd, const char* key)
624 {
625         const char *dot;
626         int i, success;
627         struct strbuf sb;
628
629         strbuf_init(&sb, 0);
630         dot = memchr(key, '.', store.baselen);
631         if (dot) {
632                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
633                 for (i = dot - key + 1; i < store.baselen; i++) {
634                         if (key[i] == '"')
635                                 strbuf_addch(&sb, '\\');
636                         strbuf_addch(&sb, key[i]);
637                 }
638                 strbuf_addstr(&sb, "\"]\n");
639         } else {
640                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
641         }
642
643         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
644         strbuf_release(&sb);
645
646         return success;
647 }
648
649 static int store_write_pair(int fd, const char* key, const char* value)
650 {
651         int i, success;
652         int length = strlen(key + store.baselen + 1);
653         const char *quote = "";
654         struct strbuf sb;
655
656         /*
657          * Check to see if the value needs to be surrounded with a dq pair.
658          * Note that problematic characters are always backslash-quoted; this
659          * check is about not losing leading or trailing SP and strings that
660          * follow beginning-of-comment characters (i.e. ';' and '#') by the
661          * configuration parser.
662          */
663         if (value[0] == ' ')
664                 quote = "\"";
665         for (i = 0; value[i]; i++)
666                 if (value[i] == ';' || value[i] == '#')
667                         quote = "\"";
668         if (i && value[i - 1] == ' ')
669                 quote = "\"";
670
671         strbuf_init(&sb, 0);
672         strbuf_addf(&sb, "\t%.*s = %s",
673                     length, key + store.baselen + 1, quote);
674
675         for (i = 0; value[i]; i++)
676                 switch (value[i]) {
677                 case '\n':
678                         strbuf_addstr(&sb, "\\n");
679                         break;
680                 case '\t':
681                         strbuf_addstr(&sb, "\\t");
682                         break;
683                 case '"':
684                 case '\\':
685                         strbuf_addch(&sb, '\\');
686                 default:
687                         strbuf_addch(&sb, value[i]);
688                         break;
689                 }
690         strbuf_addf(&sb, "%s\n", quote);
691
692         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
693         strbuf_release(&sb);
694
695         return success;
696 }
697
698 static ssize_t find_beginning_of_line(const char* contents, size_t size,
699         size_t offset_, int* found_bracket)
700 {
701         size_t equal_offset = size, bracket_offset = size;
702         ssize_t offset;
703
704         for (offset = offset_-2; offset > 0
705                         && contents[offset] != '\n'; offset--)
706                 switch (contents[offset]) {
707                         case '=': equal_offset = offset; break;
708                         case ']': bracket_offset = offset; break;
709                 }
710         if (bracket_offset < equal_offset) {
711                 *found_bracket = 1;
712                 offset = bracket_offset+1;
713         } else
714                 offset++;
715
716         return offset;
717 }
718
719 int git_config_set(const char* key, const char* value)
720 {
721         return git_config_set_multivar(key, value, NULL, 0);
722 }
723
724 /*
725  * If value==NULL, unset in (remove from) config,
726  * if value_regex!=NULL, disregard key/value pairs where value does not match.
727  * if multi_replace==0, nothing, or only one matching key/value is replaced,
728  *     else all matching key/values (regardless how many) are removed,
729  *     before the new pair is written.
730  *
731  * Returns 0 on success.
732  *
733  * This function does this:
734  *
735  * - it locks the config file by creating ".git/config.lock"
736  *
737  * - it then parses the config using store_aux() as validator to find
738  *   the position on the key/value pair to replace. If it is to be unset,
739  *   it must be found exactly once.
740  *
741  * - the config file is mmap()ed and the part before the match (if any) is
742  *   written to the lock file, then the changed part and the rest.
743  *
744  * - the config file is removed and the lock file rename()d to it.
745  *
746  */
747 int git_config_set_multivar(const char* key, const char* value,
748         const char* value_regex, int multi_replace)
749 {
750         int i, dot;
751         int fd = -1, in_fd;
752         int ret;
753         char* config_filename;
754         struct lock_file *lock = NULL;
755         const char* last_dot = strrchr(key, '.');
756
757         config_filename = getenv(CONFIG_ENVIRONMENT);
758         if (!config_filename) {
759                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
760                 if (!config_filename)
761                         config_filename  = git_path("config");
762         }
763         config_filename = xstrdup(config_filename);
764
765         /*
766          * Since "key" actually contains the section name and the real
767          * key name separated by a dot, we have to know where the dot is.
768          */
769
770         if (last_dot == NULL) {
771                 fprintf(stderr, "key does not contain a section: %s\n", key);
772                 ret = 2;
773                 goto out_free;
774         }
775         store.baselen = last_dot - key;
776
777         store.multi_replace = multi_replace;
778
779         /*
780          * Validate the key and while at it, lower case it for matching.
781          */
782         store.key = xmalloc(strlen(key) + 1);
783         dot = 0;
784         for (i = 0; key[i]; i++) {
785                 unsigned char c = key[i];
786                 if (c == '.')
787                         dot = 1;
788                 /* Leave the extended basename untouched.. */
789                 if (!dot || i > store.baselen) {
790                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
791                                 fprintf(stderr, "invalid key: %s\n", key);
792                                 free(store.key);
793                                 ret = 1;
794                                 goto out_free;
795                         }
796                         c = tolower(c);
797                 } else if (c == '\n') {
798                         fprintf(stderr, "invalid key (newline): %s\n", key);
799                         free(store.key);
800                         ret = 1;
801                         goto out_free;
802                 }
803                 store.key[i] = c;
804         }
805         store.key[i] = 0;
806
807         /*
808          * The lock serves a purpose in addition to locking: the new
809          * contents of .git/config will be written into it.
810          */
811         lock = xcalloc(sizeof(struct lock_file), 1);
812         fd = hold_lock_file_for_update(lock, config_filename, 0);
813         if (fd < 0) {
814                 fprintf(stderr, "could not lock config file\n");
815                 free(store.key);
816                 ret = -1;
817                 goto out_free;
818         }
819
820         /*
821          * If .git/config does not exist yet, write a minimal version.
822          */
823         in_fd = open(config_filename, O_RDONLY);
824         if ( in_fd < 0 ) {
825                 free(store.key);
826
827                 if ( ENOENT != errno ) {
828                         error("opening %s: %s", config_filename,
829                               strerror(errno));
830                         ret = 3; /* same as "invalid config file" */
831                         goto out_free;
832                 }
833                 /* if nothing to unset, error out */
834                 if (value == NULL) {
835                         ret = 5;
836                         goto out_free;
837                 }
838
839                 store.key = (char*)key;
840                 if (!store_write_section(fd, key) ||
841                     !store_write_pair(fd, key, value))
842                         goto write_err_out;
843         } else {
844                 struct stat st;
845                 char* contents;
846                 size_t contents_sz, copy_begin, copy_end;
847                 int i, new_line = 0;
848
849                 if (value_regex == NULL)
850                         store.value_regex = NULL;
851                 else {
852                         if (value_regex[0] == '!') {
853                                 store.do_not_match = 1;
854                                 value_regex++;
855                         } else
856                                 store.do_not_match = 0;
857
858                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
859                         if (regcomp(store.value_regex, value_regex,
860                                         REG_EXTENDED)) {
861                                 fprintf(stderr, "Invalid pattern: %s\n",
862                                         value_regex);
863                                 free(store.value_regex);
864                                 ret = 6;
865                                 goto out_free;
866                         }
867                 }
868
869                 store.offset[0] = 0;
870                 store.state = START;
871                 store.seen = 0;
872
873                 /*
874                  * After this, store.offset will contain the *end* offset
875                  * of the last match, or remain at 0 if no match was found.
876                  * As a side effect, we make sure to transform only a valid
877                  * existing config file.
878                  */
879                 if (git_config_from_file(store_aux, config_filename)) {
880                         fprintf(stderr, "invalid config file\n");
881                         free(store.key);
882                         if (store.value_regex != NULL) {
883                                 regfree(store.value_regex);
884                                 free(store.value_regex);
885                         }
886                         ret = 3;
887                         goto out_free;
888                 }
889
890                 free(store.key);
891                 if (store.value_regex != NULL) {
892                         regfree(store.value_regex);
893                         free(store.value_regex);
894                 }
895
896                 /* if nothing to unset, or too many matches, error out */
897                 if ((store.seen == 0 && value == NULL) ||
898                                 (store.seen > 1 && multi_replace == 0)) {
899                         ret = 5;
900                         goto out_free;
901                 }
902
903                 fstat(in_fd, &st);
904                 contents_sz = xsize_t(st.st_size);
905                 contents = xmmap(NULL, contents_sz, PROT_READ,
906                         MAP_PRIVATE, in_fd, 0);
907                 close(in_fd);
908
909                 if (store.seen == 0)
910                         store.seen = 1;
911
912                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
913                         if (store.offset[i] == 0) {
914                                 store.offset[i] = copy_end = contents_sz;
915                         } else if (store.state != KEY_SEEN) {
916                                 copy_end = store.offset[i];
917                         } else
918                                 copy_end = find_beginning_of_line(
919                                         contents, contents_sz,
920                                         store.offset[i]-2, &new_line);
921
922                         if (copy_end > 0 && contents[copy_end-1] != '\n')
923                                 new_line = 1;
924
925                         /* write the first part of the config */
926                         if (copy_end > copy_begin) {
927                                 if (write_in_full(fd, contents + copy_begin,
928                                                   copy_end - copy_begin) <
929                                     copy_end - copy_begin)
930                                         goto write_err_out;
931                                 if (new_line &&
932                                     write_in_full(fd, "\n", 1) != 1)
933                                         goto write_err_out;
934                         }
935                         copy_begin = store.offset[i];
936                 }
937
938                 /* write the pair (value == NULL means unset) */
939                 if (value != NULL) {
940                         if (store.state == START) {
941                                 if (!store_write_section(fd, key))
942                                         goto write_err_out;
943                         }
944                         if (!store_write_pair(fd, key, value))
945                                 goto write_err_out;
946                 }
947
948                 /* write the rest of the config */
949                 if (copy_begin < contents_sz)
950                         if (write_in_full(fd, contents + copy_begin,
951                                           contents_sz - copy_begin) <
952                             contents_sz - copy_begin)
953                                 goto write_err_out;
954
955                 munmap(contents, contents_sz);
956         }
957
958         if (commit_lock_file(lock) < 0) {
959                 fprintf(stderr, "Cannot commit config file!\n");
960                 ret = 4;
961                 goto out_free;
962         }
963
964         /*
965          * lock is committed, so don't try to roll it back below.
966          * NOTE: Since lockfile.c keeps a linked list of all created
967          * lock_file structures, it isn't safe to free(lock).  It's
968          * better to just leave it hanging around.
969          */
970         lock = NULL;
971         ret = 0;
972
973 out_free:
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 (commit_lock_file(lock) < 0)
1072                         ret = error("Cannot commit config file!");
1073  out:
1074         free(config_filename);
1075         return ret;
1076 }