Introduce new config option for mmap limit.
[git] / config.c
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  * Copyright (C) Johannes Schindelin, 2005
6  *
7  */
8 #include "cache.h"
9
10 #define MAXNAME (256)
11
12 static FILE *config_file;
13 static const char *config_file_name;
14 static int config_linenr;
15 static int get_next_char(void)
16 {
17         int c;
18         FILE *f;
19
20         c = '\n';
21         if ((f = config_file) != NULL) {
22                 c = fgetc(f);
23                 if (c == '\r') {
24                         /* DOS like systems */
25                         c = fgetc(f);
26                         if (c != '\n') {
27                                 ungetc(c, f);
28                                 c = '\r';
29                         }
30                 }
31                 if (c == '\n')
32                         config_linenr++;
33                 if (c == EOF) {
34                         config_file = NULL;
35                         c = '\n';
36                 }
37         }
38         return c;
39 }
40
41 static char *parse_value(void)
42 {
43         static char value[1024];
44         int quote = 0, comment = 0, len = 0, space = 0;
45
46         for (;;) {
47                 int c = get_next_char();
48                 if (len >= sizeof(value))
49                         return NULL;
50                 if (c == '\n') {
51                         if (quote)
52                                 return NULL;
53                         value[len] = 0;
54                         return value;
55                 }
56                 if (comment)
57                         continue;
58                 if (isspace(c) && !quote) {
59                         space = 1;
60                         continue;
61                 }
62                 if (!quote) {
63                         if (c == ';' || c == '#') {
64                                 comment = 1;
65                                 continue;
66                         }
67                 }
68                 if (space) {
69                         if (len)
70                                 value[len++] = ' ';
71                         space = 0;
72                 }
73                 if (c == '\\') {
74                         c = get_next_char();
75                         switch (c) {
76                         case '\n':
77                                 continue;
78                         case 't':
79                                 c = '\t';
80                                 break;
81                         case 'b':
82                                 c = '\b';
83                                 break;
84                         case 'n':
85                                 c = '\n';
86                                 break;
87                         /* Some characters escape as themselves */
88                         case '\\': case '"':
89                                 break;
90                         /* Reject unknown escape sequences */
91                         default:
92                                 return NULL;
93                         }
94                         value[len++] = c;
95                         continue;
96                 }
97                 if (c == '"') {
98                         quote = 1-quote;
99                         continue;
100                 }
101                 value[len++] = c;
102         }
103 }
104
105 static inline int iskeychar(int c)
106 {
107         return isalnum(c) || c == '-';
108 }
109
110 static int get_value(config_fn_t fn, char *name, unsigned int len)
111 {
112         int c;
113         char *value;
114
115         /* Get the full name */
116         for (;;) {
117                 c = get_next_char();
118                 if (c == EOF)
119                         break;
120                 if (!iskeychar(c))
121                         break;
122                 name[len++] = tolower(c);
123                 if (len >= MAXNAME)
124                         return -1;
125         }
126         name[len] = 0;
127         while (c == ' ' || c == '\t')
128                 c = get_next_char();
129
130         value = NULL;
131         if (c != '\n') {
132                 if (c != '=')
133                         return -1;
134                 value = parse_value();
135                 if (!value)
136                         return -1;
137         }
138         return fn(name, value);
139 }
140
141 static int get_extended_base_var(char *name, int baselen, int c)
142 {
143         do {
144                 if (c == '\n')
145                         return -1;
146                 c = get_next_char();
147         } while (isspace(c));
148
149         /* We require the format to be '[base "extension"]' */
150         if (c != '"')
151                 return -1;
152         name[baselen++] = '.';
153
154         for (;;) {
155                 int c = get_next_char();
156                 if (c == '\n')
157                         return -1;
158                 if (c == '"')
159                         break;
160                 if (c == '\\') {
161                         c = get_next_char();
162                         if (c == '\n')
163                                 return -1;
164                 }
165                 name[baselen++] = c;
166                 if (baselen > MAXNAME / 2)
167                         return -1;
168         }
169
170         /* Final ']' */
171         if (get_next_char() != ']')
172                 return -1;
173         return baselen;
174 }
175
176 static int get_base_var(char *name)
177 {
178         int baselen = 0;
179
180         for (;;) {
181                 int c = get_next_char();
182                 if (c == EOF)
183                         return -1;
184                 if (c == ']')
185                         return baselen;
186                 if (isspace(c))
187                         return get_extended_base_var(name, baselen, c);
188                 if (!iskeychar(c) && c != '.')
189                         return -1;
190                 if (baselen > MAXNAME / 2)
191                         return -1;
192                 name[baselen++] = tolower(c);
193         }
194 }
195
196 static int git_parse_file(config_fn_t fn)
197 {
198         int comment = 0;
199         int baselen = 0;
200         static char var[MAXNAME];
201
202         for (;;) {
203                 int c = get_next_char();
204                 if (c == '\n') {
205                         /* EOF? */
206                         if (!config_file)
207                                 return 0;
208                         comment = 0;
209                         continue;
210                 }
211                 if (comment || isspace(c))
212                         continue;
213                 if (c == '#' || c == ';') {
214                         comment = 1;
215                         continue;
216                 }
217                 if (c == '[') {
218                         baselen = get_base_var(var);
219                         if (baselen <= 0)
220                                 break;
221                         var[baselen++] = '.';
222                         var[baselen] = 0;
223                         continue;
224                 }
225                 if (!isalpha(c))
226                         break;
227                 var[baselen] = tolower(c);
228                 if (get_value(fn, var, baselen+1) < 0)
229                         break;
230         }
231         die("bad config file line %d in %s", config_linenr, config_file_name);
232 }
233
234 int git_config_int(const char *name, const char *value)
235 {
236         if (value && *value) {
237                 char *end;
238                 int val = strtol(value, &end, 0);
239                 if (!*end)
240                         return val;
241         }
242         die("bad config value for '%s' in %s", name, config_file_name);
243 }
244
245 int git_config_bool(const char *name, const char *value)
246 {
247         if (!value)
248                 return 1;
249         if (!*value)
250                 return 0;
251         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
252                 return 1;
253         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
254                 return 0;
255         return git_config_int(name, value) != 0;
256 }
257
258 int git_default_config(const char *var, const char *value)
259 {
260         /* This needs a better name */
261         if (!strcmp(var, "core.filemode")) {
262                 trust_executable_bit = git_config_bool(var, value);
263                 return 0;
264         }
265
266         if (!strcmp(var, "core.ignorestat")) {
267                 assume_unchanged = git_config_bool(var, value);
268                 return 0;
269         }
270
271         if (!strcmp(var, "core.prefersymlinkrefs")) {
272                 prefer_symlink_refs = git_config_bool(var, value);
273                 return 0;
274         }
275
276         if (!strcmp(var, "core.logallrefupdates")) {
277                 log_all_ref_updates = git_config_bool(var, value);
278                 return 0;
279         }
280
281         if (!strcmp(var, "core.warnambiguousrefs")) {
282                 warn_ambiguous_refs = git_config_bool(var, value);
283                 return 0;
284         }
285
286         if (!strcmp(var, "core.legacyheaders")) {
287                 use_legacy_headers = git_config_bool(var, value);
288                 return 0;
289         }
290
291         if (!strcmp(var, "core.compression")) {
292                 int level = git_config_int(var, value);
293                 if (level == -1)
294                         level = Z_DEFAULT_COMPRESSION;
295                 else if (level < 0 || level > Z_BEST_COMPRESSION)
296                         die("bad zlib compression level %d", level);
297                 zlib_compression_level = level;
298                 return 0;
299         }
300
301         if (!strcmp(var, "core.packedgitlimit")) {
302                 packed_git_limit = git_config_int(var, value);
303                 return 0;
304         }
305
306         if (!strcmp(var, "user.name")) {
307                 strlcpy(git_default_name, value, sizeof(git_default_name));
308                 return 0;
309         }
310
311         if (!strcmp(var, "user.email")) {
312                 strlcpy(git_default_email, value, sizeof(git_default_email));
313                 return 0;
314         }
315
316         if (!strcmp(var, "i18n.commitencoding")) {
317                 git_commit_encoding = strdup(value);
318                 return 0;
319         }
320
321         if (!strcmp(var, "i18n.logoutputencoding")) {
322                 git_log_output_encoding = strdup(value);
323                 return 0;
324         }
325
326
327         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
328                 pager_use_color = git_config_bool(var,value);
329                 return 0;
330         }
331
332         /* Add other config variables here and to Documentation/config.txt. */
333         return 0;
334 }
335
336 int git_config_from_file(config_fn_t fn, const char *filename)
337 {
338         int ret;
339         FILE *f = fopen(filename, "r");
340
341         ret = -1;
342         if (f) {
343                 config_file = f;
344                 config_file_name = filename;
345                 config_linenr = 1;
346                 ret = git_parse_file(fn);
347                 fclose(f);
348                 config_file_name = NULL;
349         }
350         return ret;
351 }
352
353 int git_config(config_fn_t fn)
354 {
355         int ret = 0;
356         char *repo_config = NULL;
357         const char *home = NULL, *filename;
358
359         /* $GIT_CONFIG makes git read _only_ the given config file,
360          * $GIT_CONFIG_LOCAL will make it process it in addition to the
361          * global config file, the same way it would the per-repository
362          * config file otherwise. */
363         filename = getenv(CONFIG_ENVIRONMENT);
364         if (!filename) {
365                 home = getenv("HOME");
366                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
367                 if (!filename)
368                         filename = repo_config = xstrdup(git_path("config"));
369         }
370
371         if (home) {
372                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
373                 if (!access(user_config, R_OK))
374                         ret = git_config_from_file(fn, user_config);
375                 free(user_config);
376         }
377
378         ret += git_config_from_file(fn, filename);
379         free(repo_config);
380         return ret;
381 }
382
383 /*
384  * Find all the stuff for git_config_set() below.
385  */
386
387 #define MAX_MATCHES 512
388
389 static struct {
390         int baselen;
391         char* key;
392         int do_not_match;
393         regex_t* value_regex;
394         int multi_replace;
395         off_t offset[MAX_MATCHES];
396         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
397         int seen;
398 } store;
399
400 static int matches(const char* key, const char* value)
401 {
402         return !strcmp(key, store.key) &&
403                 (store.value_regex == NULL ||
404                  (store.do_not_match ^
405                   !regexec(store.value_regex, value, 0, NULL, 0)));
406 }
407
408 static int store_aux(const char* key, const char* value)
409 {
410         switch (store.state) {
411         case KEY_SEEN:
412                 if (matches(key, value)) {
413                         if (store.seen == 1 && store.multi_replace == 0) {
414                                 fprintf(stderr,
415                                         "Warning: %s has multiple values\n",
416                                         key);
417                         } else if (store.seen >= MAX_MATCHES) {
418                                 fprintf(stderr, "Too many matches\n");
419                                 return 1;
420                         }
421
422                         store.offset[store.seen] = ftell(config_file);
423                         store.seen++;
424                 }
425                 break;
426         case SECTION_SEEN:
427                 if (strncmp(key, store.key, store.baselen+1)) {
428                         store.state = SECTION_END_SEEN;
429                         break;
430                 } else
431                         /* do not increment matches: this is no match */
432                         store.offset[store.seen] = ftell(config_file);
433                 /* fallthru */
434         case SECTION_END_SEEN:
435         case START:
436                 if (matches(key, value)) {
437                         store.offset[store.seen] = ftell(config_file);
438                         store.state = KEY_SEEN;
439                         store.seen++;
440                 } else {
441                         if (strrchr(key, '.') - key == store.baselen &&
442                               !strncmp(key, store.key, store.baselen)) {
443                                         store.state = SECTION_SEEN;
444                                         store.offset[store.seen] = ftell(config_file);
445                         }
446                 }
447         }
448         return 0;
449 }
450
451 static void store_write_section(int fd, const char* key)
452 {
453         const char *dot = strchr(key, '.');
454         int len1 = store.baselen, len2 = -1;
455
456         dot = strchr(key, '.');
457         if (dot) {
458                 int dotlen = dot - key;
459                 if (dotlen < len1) {
460                         len2 = len1 - dotlen - 1;
461                         len1 = dotlen;
462                 }
463         }
464
465         write(fd, "[", 1);
466         write(fd, key, len1);
467         if (len2 >= 0) {
468                 write(fd, " \"", 2);
469                 while (--len2 >= 0) {
470                         unsigned char c = *++dot;
471                         if (c == '"')
472                                 write(fd, "\\", 1);
473                         write(fd, &c, 1);
474                 }
475                 write(fd, "\"", 1);
476         }
477         write(fd, "]\n", 2);
478 }
479
480 static void store_write_pair(int fd, const char* key, const char* value)
481 {
482         int i;
483
484         write(fd, "\t", 1);
485         write(fd, key+store.baselen+1,
486                 strlen(key+store.baselen+1));
487         write(fd, " = ", 3);
488         for (i = 0; value[i]; i++)
489                 switch (value[i]) {
490                 case '\n': write(fd, "\\n", 2); break;
491                 case '\t': write(fd, "\\t", 2); break;
492                 case '"': case '\\': write(fd, "\\", 1);
493                 default: write(fd, value+i, 1);
494         }
495         write(fd, "\n", 1);
496 }
497
498 static int find_beginning_of_line(const char* contents, int size,
499         int offset_, int* found_bracket)
500 {
501         int equal_offset = size, bracket_offset = size;
502         int offset;
503
504         for (offset = offset_-2; offset > 0 
505                         && contents[offset] != '\n'; offset--)
506                 switch (contents[offset]) {
507                         case '=': equal_offset = offset; break;
508                         case ']': bracket_offset = offset; break;
509                 }
510         if (bracket_offset < equal_offset) {
511                 *found_bracket = 1;
512                 offset = bracket_offset+1;
513         } else
514                 offset++;
515
516         return offset;
517 }
518
519 int git_config_set(const char* key, const char* value)
520 {
521         return git_config_set_multivar(key, value, NULL, 0);
522 }
523
524 /*
525  * If value==NULL, unset in (remove from) config,
526  * if value_regex!=NULL, disregard key/value pairs where value does not match.
527  * if multi_replace==0, nothing, or only one matching key/value is replaced,
528  *     else all matching key/values (regardless how many) are removed,
529  *     before the new pair is written.
530  *
531  * Returns 0 on success.
532  *
533  * This function does this:
534  *
535  * - it locks the config file by creating ".git/config.lock"
536  *
537  * - it then parses the config using store_aux() as validator to find
538  *   the position on the key/value pair to replace. If it is to be unset,
539  *   it must be found exactly once.
540  *
541  * - the config file is mmap()ed and the part before the match (if any) is
542  *   written to the lock file, then the changed part and the rest.
543  *
544  * - the config file is removed and the lock file rename()d to it.
545  *
546  */
547 int git_config_set_multivar(const char* key, const char* value,
548         const char* value_regex, int multi_replace)
549 {
550         int i, dot;
551         int fd = -1, in_fd;
552         int ret;
553         char* config_filename;
554         char* lock_file;
555         const char* last_dot = strrchr(key, '.');
556
557         config_filename = getenv(CONFIG_ENVIRONMENT);
558         if (!config_filename) {
559                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
560                 if (!config_filename)
561                         config_filename  = git_path("config");
562         }
563         config_filename = xstrdup(config_filename);
564         lock_file = xstrdup(mkpath("%s.lock", config_filename));
565
566         /*
567          * Since "key" actually contains the section name and the real
568          * key name separated by a dot, we have to know where the dot is.
569          */
570
571         if (last_dot == NULL) {
572                 fprintf(stderr, "key does not contain a section: %s\n", key);
573                 ret = 2;
574                 goto out_free;
575         }
576         store.baselen = last_dot - key;
577
578         store.multi_replace = multi_replace;
579
580         /*
581          * Validate the key and while at it, lower case it for matching.
582          */
583         store.key = xmalloc(strlen(key) + 1);
584         dot = 0;
585         for (i = 0; key[i]; i++) {
586                 unsigned char c = key[i];
587                 if (c == '.')
588                         dot = 1;
589                 /* Leave the extended basename untouched.. */
590                 if (!dot || i > store.baselen) {
591                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
592                                 fprintf(stderr, "invalid key: %s\n", key);
593                                 free(store.key);
594                                 ret = 1;
595                                 goto out_free;
596                         }
597                         c = tolower(c);
598                 }
599                 store.key[i] = c;
600         }
601         store.key[i] = 0;
602
603         /*
604          * The lock_file serves a purpose in addition to locking: the new
605          * contents of .git/config will be written into it.
606          */
607         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
608         if (fd < 0 || adjust_shared_perm(lock_file)) {
609                 fprintf(stderr, "could not lock config file\n");
610                 free(store.key);
611                 ret = -1;
612                 goto out_free;
613         }
614
615         /*
616          * If .git/config does not exist yet, write a minimal version.
617          */
618         in_fd = open(config_filename, O_RDONLY);
619         if ( in_fd < 0 ) {
620                 free(store.key);
621
622                 if ( ENOENT != errno ) {
623                         error("opening %s: %s", config_filename,
624                               strerror(errno));
625                         ret = 3; /* same as "invalid config file" */
626                         goto out_free;
627                 }
628                 /* if nothing to unset, error out */
629                 if (value == NULL) {
630                         ret = 5;
631                         goto out_free;
632                 }
633
634                 store.key = (char*)key;
635                 store_write_section(fd, key);
636                 store_write_pair(fd, key, value);
637         } else{
638                 struct stat st;
639                 char* contents;
640                 int i, copy_begin, copy_end, new_line = 0;
641
642                 if (value_regex == NULL)
643                         store.value_regex = NULL;
644                 else {
645                         if (value_regex[0] == '!') {
646                                 store.do_not_match = 1;
647                                 value_regex++;
648                         } else
649                                 store.do_not_match = 0;
650
651                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
652                         if (regcomp(store.value_regex, value_regex,
653                                         REG_EXTENDED)) {
654                                 fprintf(stderr, "Invalid pattern: %s\n",
655                                         value_regex);
656                                 free(store.value_regex);
657                                 ret = 6;
658                                 goto out_free;
659                         }
660                 }
661
662                 store.offset[0] = 0;
663                 store.state = START;
664                 store.seen = 0;
665
666                 /*
667                  * After this, store.offset will contain the *end* offset
668                  * of the last match, or remain at 0 if no match was found.
669                  * As a side effect, we make sure to transform only a valid
670                  * existing config file.
671                  */
672                 if (git_config_from_file(store_aux, config_filename)) {
673                         fprintf(stderr, "invalid config file\n");
674                         free(store.key);
675                         if (store.value_regex != NULL) {
676                                 regfree(store.value_regex);
677                                 free(store.value_regex);
678                         }
679                         ret = 3;
680                         goto out_free;
681                 }
682
683                 free(store.key);
684                 if (store.value_regex != NULL) {
685                         regfree(store.value_regex);
686                         free(store.value_regex);
687                 }
688
689                 /* if nothing to unset, or too many matches, error out */
690                 if ((store.seen == 0 && value == NULL) ||
691                                 (store.seen > 1 && multi_replace == 0)) {
692                         ret = 5;
693                         goto out_free;
694                 }
695
696                 fstat(in_fd, &st);
697                 contents = mmap(NULL, st.st_size, PROT_READ,
698                         MAP_PRIVATE, in_fd, 0);
699                 close(in_fd);
700
701                 if (store.seen == 0)
702                         store.seen = 1;
703
704                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
705                         if (store.offset[i] == 0) {
706                                 store.offset[i] = copy_end = st.st_size;
707                         } else if (store.state != KEY_SEEN) {
708                                 copy_end = store.offset[i];
709                         } else
710                                 copy_end = find_beginning_of_line(
711                                         contents, st.st_size,
712                                         store.offset[i]-2, &new_line);
713
714                         /* write the first part of the config */
715                         if (copy_end > copy_begin) {
716                                 write(fd, contents + copy_begin,
717                                 copy_end - copy_begin);
718                                 if (new_line)
719                                         write(fd, "\n", 1);
720                         }
721                         copy_begin = store.offset[i];
722                 }
723
724                 /* write the pair (value == NULL means unset) */
725                 if (value != NULL) {
726                         if (store.state == START)
727                                 store_write_section(fd, key);
728                         store_write_pair(fd, key, value);
729                 }
730
731                 /* write the rest of the config */
732                 if (copy_begin < st.st_size)
733                         write(fd, contents + copy_begin,
734                                 st.st_size - copy_begin);
735
736                 munmap(contents, st.st_size);
737                 unlink(config_filename);
738         }
739
740         if (rename(lock_file, config_filename) < 0) {
741                 fprintf(stderr, "Could not rename the lock file?\n");
742                 ret = 4;
743                 goto out_free;
744         }
745
746         ret = 0;
747
748 out_free:
749         if (0 <= fd)
750                 close(fd);
751         free(config_filename);
752         if (lock_file) {
753                 unlink(lock_file);
754                 free(lock_file);
755         }
756         return ret;
757 }
758
759 int git_config_rename_section(const char *old_name, const char *new_name)
760 {
761         int ret = 0;
762         char *config_filename;
763         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
764         int out_fd;
765         char buf[1024];
766
767         config_filename = getenv(CONFIG_ENVIRONMENT);
768         if (!config_filename) {
769                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
770                 if (!config_filename)
771                         config_filename  = git_path("config");
772         }
773         config_filename = xstrdup(config_filename);
774         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
775         if (out_fd < 0) {
776                 ret = error("Could not lock config file!");
777                 goto out;
778         }
779
780         if (!(config_file = fopen(config_filename, "rb"))) {
781                 ret = error("Could not open config file!");
782                 goto out;
783         }
784
785         while (fgets(buf, sizeof(buf), config_file)) {
786                 int i;
787                 for (i = 0; buf[i] && isspace(buf[i]); i++)
788                         ; /* do nothing */
789                 if (buf[i] == '[') {
790                         /* it's a section */
791                         int j = 0, dot = 0;
792                         for (i++; buf[i] && buf[i] != ']'; i++) {
793                                 if (!dot && isspace(buf[i])) {
794                                         dot = 1;
795                                         if (old_name[j++] != '.')
796                                                 break;
797                                         for (i++; isspace(buf[i]); i++)
798                                                 ; /* do nothing */
799                                         if (buf[i] != '"')
800                                                 break;
801                                         continue;
802                                 }
803                                 if (buf[i] == '\\' && dot)
804                                         i++;
805                                 else if (buf[i] == '"' && dot) {
806                                         for (i++; isspace(buf[i]); i++)
807                                                 ; /* do_nothing */
808                                         break;
809                                 }
810                                 if (buf[i] != old_name[j++])
811                                         break;
812                         }
813                         if (buf[i] == ']') {
814                                 /* old_name matches */
815                                 ret++;
816                                 store.baselen = strlen(new_name);
817                                 store_write_section(out_fd, new_name);
818                                 continue;
819                         }
820                 }
821                 write(out_fd, buf, strlen(buf));
822         }
823         fclose(config_file);
824         if (close(out_fd) || commit_lock_file(lock) < 0)
825                 ret = error("Cannot commit config file!");
826  out:
827         free(config_filename);
828         return ret;
829 }
830