config.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  * Copyright (C) Johannes Schindelin, 2005
   6  *
   7  */
   8 #include "cache.h"
   9
  10 #define MAXNAME (256)
  11
  12 static FILE *config_file;
  13 static const char *config_file_name;
  14 static int config_linenr;
  15 static int get_next_char(void)
  16 {
  17         int c;
  18         FILE *f;
  19
  20         c = '\n';
  21         if ((f = config_file) != NULL) {
  22                 c = fgetc(f);
  23                 if (c == '\r') {
  24                         /* DOS like systems */
  25                         c = fgetc(f);
  26                         if (c != '\n') {
  27                                 ungetc(c, f);
  28                                 c = '\r';
  29                         }
  30                 }
  31                 if (c == '\n')
  32                         config_linenr++;
  33                 if (c == EOF) {
  34                         config_file = NULL;
  35                         c = '\n';
  36                 }
  37         }
  38         return c;
  39 }
  40
  41 static char *parse_value(void)
  42 {
  43         static char value[1024];
  44         int quote = 0, comment = 0, len = 0, space = 0;
  45
  46         for (;;) {
  47                 int c = get_next_char();
  48                 if (len >= sizeof(value))
  49                         return NULL;
  50                 if (c == '\n') {
  51                         if (quote)
  52                                 return NULL;
  53                         value[len] = 0;
  54                         return value;
  55                 }
  56                 if (comment)
  57                         continue;
  58                 if (isspace(c) && !quote) {
  59                         space = 1;
  60                         continue;
  61                 }
  62                 if (!quote) {
  63                         if (c == ';' || c == '#') {
  64                                 comment = 1;
  65                                 continue;
  66                         }
  67                 }
  68                 if (space) {
  69                         if (len)
  70                                 value[len++] = ' ';
  71                         space = 0;
  72                 }
  73                 if (c == '\\') {
  74                         c = get_next_char();
  75                         switch (c) {
  76                         case '\n':
  77                                 continue;
  78                         case 't':
  79                                 c = '\t';
  80                                 break;
  81                         case 'b':
  82                                 c = '\b';
  83                                 break;
  84                         case 'n':
  85                                 c = '\n';
  86                                 break;
  87                         /* Some characters escape as themselves */
  88                         case '\\': case '"':
  89                                 break;
  90                         /* Reject unknown escape sequences */
  91                         default:
  92                                 return NULL;
  93                         }
  94                         value[len++] = c;
  95                         continue;
  96                 }
  97                 if (c == '"') {
  98                         quote = 1-quote;
  99                         continue;
 100                 }
 101                 value[len++] = c;
 102         }
 103 }
 104
 105 static inline int iskeychar(int c)
 106 {
 107         return isalnum(c) || c == '-';
 108 }
 109
 110 static int get_value(config_fn_t fn, char *name, unsigned int len)
 111 {
 112         int c;
 113         char *value;
 114
 115         /* Get the full name */
 116         for (;;) {
 117                 c = get_next_char();
 118                 if (c == EOF)
 119                         break;
 120                 if (!iskeychar(c))
 121                         break;
 122                 name[len++] = tolower(c);
 123                 if (len >= MAXNAME)
 124                         return -1;
 125         }
 126         name[len] = 0;
 127         while (c == ' ' || c == '\t')
 128                 c = get_next_char();
 129
 130         value = NULL;
 131         if (c != '\n') {
 132                 if (c != '=')
 133                         return -1;
 134                 value = parse_value();
 135                 if (!value)
 136                         return -1;
 137         }
 138         return fn(name, value);
 139 }
 140
 141 static int get_extended_base_var(char *name, int baselen, int c)
 142 {
 143         do {
 144                 if (c == '\n')
 145                         return -1;
 146                 c = get_next_char();
 147         } while (isspace(c));
 148
 149         /* We require the format to be '[base "extension"]' */
 150         if (c != '"')
 151                 return -1;
 152         name[baselen++] = '.';
 153
 154         for (;;) {
 155                 int c = get_next_char();
 156                 if (c == '\n')
 157                         return -1;
 158                 if (c == '"')
 159                         break;
 160                 if (c == '\\') {
 161                         c = get_next_char();
 162                         if (c == '\n')
 163                                 return -1;
 164                 }
 165                 name[baselen++] = c;
 166                 if (baselen > MAXNAME / 2)
 167                         return -1;
 168         }
 169
 170         /* Final ']' */
 171         if (get_next_char() != ']')
 172                 return -1;
 173         return baselen;
 174 }
 175
 176 static int get_base_var(char *name)
 177 {
 178         int baselen = 0;
 179
 180         for (;;) {
 181                 int c = get_next_char();
 182                 if (c == EOF)
 183                         return -1;
 184                 if (c == ']')
 185                         return baselen;
 186                 if (isspace(c))
 187                         return get_extended_base_var(name, baselen, c);
 188                 if (!iskeychar(c) && c != '.')
 189                         return -1;
 190                 if (baselen > MAXNAME / 2)
 191                         return -1;
 192                 name[baselen++] = tolower(c);
 193         }
 194 }
 195
 196 static int git_parse_file(config_fn_t fn)
 197 {
 198         int comment = 0;
 199         int baselen = 0;
 200         static char var[MAXNAME];
 201
 202         for (;;) {
 203                 int c = get_next_char();
 204                 if (c == '\n') {
 205                         /* EOF? */
 206                         if (!config_file)
 207                                 return 0;
 208                         comment = 0;
 209                         continue;
 210                 }
 211                 if (comment || isspace(c))
 212                         continue;
 213                 if (c == '#' || c == ';') {
 214                         comment = 1;
 215                         continue;
 216                 }
 217                 if (c == '[') {
 218                         baselen = get_base_var(var);
 219                         if (baselen <= 0)
 220                                 break;
 221                         var[baselen++] = '.';
 222                         var[baselen] = 0;
 223                         continue;
 224                 }
 225                 if (!isalpha(c))
 226                         break;
 227                 var[baselen] = tolower(c);
 228                 if (get_value(fn, var, baselen+1) < 0)
 229                         break;
 230         }
 231         die("bad config file line %d in %s", config_linenr, config_file_name);
 232 }
 233
 234 int git_config_int(const char *name, const char *value)
 235 {
 236         if (value && *value) {
 237                 char *end;
 238                 int val = strtol(value, &end, 0);
 239                 if (!*end)
 240                         return val;
 241                 if (!strcasecmp(end, "k"))
 242                         return val * 1024;
 243                 if (!strcasecmp(end, "m"))
 244                         return val * 1024 * 1024;
 245                 if (!strcasecmp(end, "g"))
 246                         return val * 1024 * 1024 * 1024;
 247         }
 248         die("bad config value for '%s' in %s", name, config_file_name);
 249 }
 250
 251 int git_config_bool(const char *name, const char *value)
 252 {
 253         if (!value)
 254                 return 1;
 255         if (!*value)
 256                 return 0;
 257         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 258                 return 1;
 259         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 260                 return 0;
 261         return git_config_int(name, value) != 0;
 262 }
 263
 264 int git_default_config(const char *var, const char *value)
 265 {
 266         /* This needs a better name */
 267         if (!strcmp(var, "core.filemode")) {
 268                 trust_executable_bit = git_config_bool(var, value);
 269                 return 0;
 270         }
 271
 272         if (!strcmp(var, "core.ignorestat")) {
 273                 assume_unchanged = git_config_bool(var, value);
 274                 return 0;
 275         }
 276
 277         if (!strcmp(var, "core.prefersymlinkrefs")) {
 278                 prefer_symlink_refs = git_config_bool(var, value);
 279                 return 0;
 280         }
 281
 282         if (!strcmp(var, "core.logallrefupdates")) {
 283                 log_all_ref_updates = git_config_bool(var, value);
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "core.warnambiguousrefs")) {
 288                 warn_ambiguous_refs = git_config_bool(var, value);
 289                 return 0;
 290         }
 291
 292         if (!strcmp(var, "core.legacyheaders")) {
 293                 use_legacy_headers = git_config_bool(var, value);
 294                 return 0;
 295         }
 296
 297         if (!strcmp(var, "core.compression")) {
 298                 int level = git_config_int(var, value);
 299                 if (level == -1)
 300                         level = Z_DEFAULT_COMPRESSION;
 301                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 302                         die("bad zlib compression level %d", level);
 303                 zlib_compression_level = level;
 304                 return 0;
 305         }
 306
 307         if (!strcmp(var, "core.packedgitwindowsize")) {
 308                 int pgsz = getpagesize();
 309                 packed_git_window_size = git_config_int(var, value);
 310                 packed_git_window_size /= pgsz;
 311                 if (packed_git_window_size < 2)
 312                         packed_git_window_size = 2;
 313                 packed_git_window_size *= pgsz;
 314                 return 0;
 315         }
 316
 317         if (!strcmp(var, "core.packedgitlimit")) {
 318                 packed_git_limit = git_config_int(var, value);
 319                 return 0;
 320         }
 321
 322         if (!strcmp(var, "user.name")) {
 323                 strlcpy(git_default_name, value, sizeof(git_default_name));
 324                 return 0;
 325         }
 326
 327         if (!strcmp(var, "user.email")) {
 328                 strlcpy(git_default_email, value, sizeof(git_default_email));
 329                 return 0;
 330         }
 331
 332         if (!strcmp(var, "i18n.commitencoding")) {
 333                 git_commit_encoding = strdup(value);
 334                 return 0;
 335         }
 336
 337         if (!strcmp(var, "i18n.logoutputencoding")) {
 338                 git_log_output_encoding = strdup(value);
 339                 return 0;
 340         }
 341
 342
 343         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 344                 pager_use_color = git_config_bool(var,value);
 345                 return 0;
 346         }
 347
 348         /* Add other config variables here and to Documentation/config.txt. */
 349         return 0;
 350 }
 351
 352 int git_config_from_file(config_fn_t fn, const char *filename)
 353 {
 354         int ret;
 355         FILE *f = fopen(filename, "r");
 356
 357         ret = -1;
 358         if (f) {
 359                 config_file = f;
 360                 config_file_name = filename;
 361                 config_linenr = 1;
 362                 ret = git_parse_file(fn);
 363                 fclose(f);
 364                 config_file_name = NULL;
 365         }
 366         return ret;
 367 }
 368
 369 int git_config(config_fn_t fn)
 370 {
 371         int ret = 0;
 372         char *repo_config = NULL;
 373         const char *home = NULL, *filename;
 374
 375         /* $GIT_CONFIG makes git read _only_ the given config file,
 376          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 377          * global config file, the same way it would the per-repository
 378          * config file otherwise. */
 379         filename = getenv(CONFIG_ENVIRONMENT);
 380         if (!filename) {
 381                 home = getenv("HOME");
 382                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 383                 if (!filename)
 384                         filename = repo_config = xstrdup(git_path("config"));
 385         }
 386
 387         if (home) {
 388                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 389                 if (!access(user_config, R_OK))
 390                         ret = git_config_from_file(fn, user_config);
 391                 free(user_config);
 392         }
 393
 394         ret += git_config_from_file(fn, filename);
 395         free(repo_config);
 396         return ret;
 397 }
 398
 399 /*
 400  * Find all the stuff for git_config_set() below.
 401  */
 402
 403 #define MAX_MATCHES 512
 404
 405 static struct {
 406         int baselen;
 407         char* key;
 408         int do_not_match;
 409         regex_t* value_regex;
 410         int multi_replace;
 411         off_t offset[MAX_MATCHES];
 412         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 413         int seen;
 414 } store;
 415
 416 static int matches(const char* key, const char* value)
 417 {
 418         return !strcmp(key, store.key) &&
 419                 (store.value_regex == NULL ||
 420                  (store.do_not_match ^
 421                   !regexec(store.value_regex, value, 0, NULL, 0)));
 422 }
 423
 424 static int store_aux(const char* key, const char* value)
 425 {
 426         switch (store.state) {
 427         case KEY_SEEN:
 428                 if (matches(key, value)) {
 429                         if (store.seen == 1 && store.multi_replace == 0) {
 430                                 fprintf(stderr,
 431                                         "Warning: %s has multiple values\n",
 432                                         key);
 433                         } else if (store.seen >= MAX_MATCHES) {
 434                                 fprintf(stderr, "Too many matches\n");
 435                                 return 1;
 436                         }
 437
 438                         store.offset[store.seen] = ftell(config_file);
 439                         store.seen++;
 440                 }
 441                 break;
 442         case SECTION_SEEN:
 443                 if (strncmp(key, store.key, store.baselen+1)) {
 444                         store.state = SECTION_END_SEEN;
 445                         break;
 446                 } else
 447                         /* do not increment matches: this is no match */
 448                         store.offset[store.seen] = ftell(config_file);
 449                 /* fallthru */
 450         case SECTION_END_SEEN:
 451         case START:
 452                 if (matches(key, value)) {
 453                         store.offset[store.seen] = ftell(config_file);
 454                         store.state = KEY_SEEN;
 455                         store.seen++;
 456                 } else {
 457                         if (strrchr(key, '.') - key == store.baselen &&
 458                               !strncmp(key, store.key, store.baselen)) {
 459                                         store.state = SECTION_SEEN;
 460                                         store.offset[store.seen] = ftell(config_file);
 461                         }
 462                 }
 463         }
 464         return 0;
 465 }
 466
 467 static int write_error()
 468 {
 469         fprintf(stderr, "Failed to write new configuration file\n");
 470
 471         /* Same error code as "failed to rename". */
 472         return 4;
 473 }
 474
 475 static int store_write_section(int fd, const char* key)
 476 {
 477         const char *dot = strchr(key, '.');
 478         int len1 = store.baselen, len2 = -1;
 479
 480         dot = strchr(key, '.');
 481         if (dot) {
 482                 int dotlen = dot - key;
 483                 if (dotlen < len1) {
 484                         len2 = len1 - dotlen - 1;
 485                         len1 = dotlen;
 486                 }
 487         }
 488
 489         if (write_in_full(fd, "[", 1) != 1 ||
 490             write_in_full(fd, key, len1) != len1)
 491                 return 0;
 492         if (len2 >= 0) {
 493                 if (write_in_full(fd, " \"", 2) != 2)
 494                         return 0;
 495                 while (--len2 >= 0) {
 496                         unsigned char c = *++dot;
 497                         if (c == '"')
 498                                 if (write_in_full(fd, "\\", 1) != 1)
 499                                         return 0;
 500                         if (write_in_full(fd, &c, 1) != 1)
 501                                 return 0;
 502                 }
 503                 if (write_in_full(fd, "\"", 1) != 1)
 504                         return 0;
 505         }
 506         if (write_in_full(fd, "]\n", 2) != 2)
 507                 return 0;
 508
 509         return 1;
 510 }
 511
 512 static int store_write_pair(int fd, const char* key, const char* value)
 513 {
 514         int i;
 515         int length = strlen(key+store.baselen+1);
 516
 517         if (write_in_full(fd, "\t", 1) != 1 ||
 518             write_in_full(fd, key+store.baselen+1, length) != length ||
 519             write_in_full(fd, " = ", 3) != 3)
 520                 return 0;
 521         for (i = 0; value[i]; i++)
 522                 switch (value[i]) {
 523                 case '\n':
 524                         if (write_in_full(fd, "\\n", 2) != 2)
 525                                 return 0;
 526                         break;
 527                 case '\t':
 528                         if (write_in_full(fd, "\\t", 2) != 2)
 529                                 return 0;
 530                         break;
 531                 case '"':
 532                 case '\\':
 533                         if (write_in_full(fd, "\\", 1) != 1)
 534                                 return 0;
 535                 default:
 536                         if (write_in_full(fd, value+i, 1) != 1)
 537                                 return 0;
 538                         break;
 539                 }
 540         if (write_in_full(fd, "\n", 1) != 1)
 541                 return 0;
 542         return 1;
 543 }
 544
 545 static int find_beginning_of_line(const char* contents, int size,
 546         int offset_, int* found_bracket)
 547 {
 548         int equal_offset = size, bracket_offset = size;
 549         int offset;
 550
 551         for (offset = offset_-2; offset > 0
 552                         && contents[offset] != '\n'; offset--)
 553                 switch (contents[offset]) {
 554                         case '=': equal_offset = offset; break;
 555                         case ']': bracket_offset = offset; break;
 556                 }
 557         if (bracket_offset < equal_offset) {
 558                 *found_bracket = 1;
 559                 offset = bracket_offset+1;
 560         } else
 561                 offset++;
 562
 563         return offset;
 564 }
 565
 566 int git_config_set(const char* key, const char* value)
 567 {
 568         return git_config_set_multivar(key, value, NULL, 0);
 569 }
 570
 571 /*
 572  * If value==NULL, unset in (remove from) config,
 573  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 574  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 575  *     else all matching key/values (regardless how many) are removed,
 576  *     before the new pair is written.
 577  *
 578  * Returns 0 on success.
 579  *
 580  * This function does this:
 581  *
 582  * - it locks the config file by creating ".git/config.lock"
 583  *
 584  * - it then parses the config using store_aux() as validator to find
 585  *   the position on the key/value pair to replace. If it is to be unset,
 586  *   it must be found exactly once.
 587  *
 588  * - the config file is mmap()ed and the part before the match (if any) is
 589  *   written to the lock file, then the changed part and the rest.
 590  *
 591  * - the config file is removed and the lock file rename()d to it.
 592  *
 593  */
 594 int git_config_set_multivar(const char* key, const char* value,
 595         const char* value_regex, int multi_replace)
 596 {
 597         int i, dot;
 598         int fd = -1, in_fd;
 599         int ret;
 600         char* config_filename;
 601         char* lock_file;
 602         const char* last_dot = strrchr(key, '.');
 603
 604         config_filename = getenv(CONFIG_ENVIRONMENT);
 605         if (!config_filename) {
 606                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 607                 if (!config_filename)
 608                         config_filename  = git_path("config");
 609         }
 610         config_filename = xstrdup(config_filename);
 611         lock_file = xstrdup(mkpath("%s.lock", config_filename));
 612
 613         /*
 614          * Since "key" actually contains the section name and the real
 615          * key name separated by a dot, we have to know where the dot is.
 616          */
 617
 618         if (last_dot == NULL) {
 619                 fprintf(stderr, "key does not contain a section: %s\n", key);
 620                 ret = 2;
 621                 goto out_free;
 622         }
 623         store.baselen = last_dot - key;
 624
 625         store.multi_replace = multi_replace;
 626
 627         /*
 628          * Validate the key and while at it, lower case it for matching.
 629          */
 630         store.key = xmalloc(strlen(key) + 1);
 631         dot = 0;
 632         for (i = 0; key[i]; i++) {
 633                 unsigned char c = key[i];
 634                 if (c == '.')
 635                         dot = 1;
 636                 /* Leave the extended basename untouched.. */
 637                 if (!dot || i > store.baselen) {
 638                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 639                                 fprintf(stderr, "invalid key: %s\n", key);
 640                                 free(store.key);
 641                                 ret = 1;
 642                                 goto out_free;
 643                         }
 644                         c = tolower(c);
 645                 }
 646                 store.key[i] = c;
 647         }
 648         store.key[i] = 0;
 649
 650         /*
 651          * The lock_file serves a purpose in addition to locking: the new
 652          * contents of .git/config will be written into it.
 653          */
 654         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 655         if (fd < 0 || adjust_shared_perm(lock_file)) {
 656                 fprintf(stderr, "could not lock config file\n");
 657                 free(store.key);
 658                 ret = -1;
 659                 goto out_free;
 660         }
 661
 662         /*
 663          * If .git/config does not exist yet, write a minimal version.
 664          */
 665         in_fd = open(config_filename, O_RDONLY);
 666         if ( in_fd < 0 ) {
 667                 free(store.key);
 668
 669                 if ( ENOENT != errno ) {
 670                         error("opening %s: %s", config_filename,
 671                               strerror(errno));
 672                         ret = 3; /* same as "invalid config file" */
 673                         goto out_free;
 674                 }
 675                 /* if nothing to unset, error out */
 676                 if (value == NULL) {
 677                         ret = 5;
 678                         goto out_free;
 679                 }
 680
 681                 store.key = (char*)key;
 682                 if (!store_write_section(fd, key) ||
 683                     !store_write_pair(fd, key, value)) {
 684                         ret = write_error();
 685                         goto out_free;
 686                 }
 687         } else{
 688                 struct stat st;
 689                 char* contents;
 690                 int i, copy_begin, copy_end, new_line = 0;
 691
 692                 if (value_regex == NULL)
 693                         store.value_regex = NULL;
 694                 else {
 695                         if (value_regex[0] == '!') {
 696                                 store.do_not_match = 1;
 697                                 value_regex++;
 698                         } else
 699                                 store.do_not_match = 0;
 700
 701                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 702                         if (regcomp(store.value_regex, value_regex,
 703                                         REG_EXTENDED)) {
 704                                 fprintf(stderr, "Invalid pattern: %s\n",
 705                                         value_regex);
 706                                 free(store.value_regex);
 707                                 ret = 6;
 708                                 goto out_free;
 709                         }
 710                 }
 711
 712                 store.offset[0] = 0;
 713                 store.state = START;
 714                 store.seen = 0;
 715
 716                 /*
 717                  * After this, store.offset will contain the *end* offset
 718                  * of the last match, or remain at 0 if no match was found.
 719                  * As a side effect, we make sure to transform only a valid
 720                  * existing config file.
 721                  */
 722                 if (git_config_from_file(store_aux, config_filename)) {
 723                         fprintf(stderr, "invalid config file\n");
 724                         free(store.key);
 725                         if (store.value_regex != NULL) {
 726                                 regfree(store.value_regex);
 727                                 free(store.value_regex);
 728                         }
 729                         ret = 3;
 730                         goto out_free;
 731                 }
 732
 733                 free(store.key);
 734                 if (store.value_regex != NULL) {
 735                         regfree(store.value_regex);
 736                         free(store.value_regex);
 737                 }
 738
 739                 /* if nothing to unset, or too many matches, error out */
 740                 if ((store.seen == 0 && value == NULL) ||
 741                                 (store.seen > 1 && multi_replace == 0)) {
 742                         ret = 5;
 743                         goto out_free;
 744                 }
 745
 746                 fstat(in_fd, &st);
 747                 contents = xmmap(NULL, st.st_size, PROT_READ,
 748                         MAP_PRIVATE, in_fd, 0);
 749                 close(in_fd);
 750
 751                 if (store.seen == 0)
 752                         store.seen = 1;
 753
 754                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 755                         if (store.offset[i] == 0) {
 756                                 store.offset[i] = copy_end = st.st_size;
 757                         } else if (store.state != KEY_SEEN) {
 758                                 copy_end = store.offset[i];
 759                         } else
 760                                 copy_end = find_beginning_of_line(
 761                                         contents, st.st_size,
 762                                         store.offset[i]-2, &new_line);
 763
 764                         /* write the first part of the config */
 765                         if (copy_end > copy_begin) {
 766                                 write_in_full(fd, contents + copy_begin,
 767                                 copy_end - copy_begin);
 768                                 if (new_line)
 769                                         write_in_full(fd, "\n", 1);
 770                         }
 771                         copy_begin = store.offset[i];
 772                 }
 773
 774                 /* write the pair (value == NULL means unset) */
 775                 if (value != NULL) {
 776                         if (store.state == START)
 777                                 if (!store_write_section(fd, key)) {
 778                                         ret = write_error();
 779                                         goto out_free;
 780                                 }
 781                         if (!store_write_pair(fd, key, value)) {
 782                                 ret = write_error();
 783                                 goto out_free;
 784                         }
 785                 }
 786
 787                 /* write the rest of the config */
 788                 if (copy_begin < st.st_size)
 789                         write_in_full(fd, contents + copy_begin,
 790                                 st.st_size - copy_begin);
 791
 792                 munmap(contents, st.st_size);
 793                 unlink(config_filename);
 794         }
 795
 796         if (rename(lock_file, config_filename) < 0) {
 797                 fprintf(stderr, "Could not rename the lock file?\n");
 798                 ret = 4;
 799                 goto out_free;
 800         }
 801
 802         ret = 0;
 803
 804 out_free:
 805         if (0 <= fd)
 806                 close(fd);
 807         free(config_filename);
 808         if (lock_file) {
 809                 unlink(lock_file);
 810                 free(lock_file);
 811         }
 812         return ret;
 813 }
 814
 815 int git_config_rename_section(const char *old_name, const char *new_name)
 816 {
 817         int ret = 0;
 818         char *config_filename;
 819         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 820         int out_fd;
 821         char buf[1024];
 822
 823         config_filename = getenv(CONFIG_ENVIRONMENT);
 824         if (!config_filename) {
 825                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 826                 if (!config_filename)
 827                         config_filename  = git_path("config");
 828         }
 829         config_filename = xstrdup(config_filename);
 830         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 831         if (out_fd < 0) {
 832                 ret = error("Could not lock config file!");
 833                 goto out;
 834         }
 835
 836         if (!(config_file = fopen(config_filename, "rb"))) {
 837                 ret = error("Could not open config file!");
 838                 goto out;
 839         }
 840
 841         while (fgets(buf, sizeof(buf), config_file)) {
 842                 int i;
 843                 int length;
 844                 for (i = 0; buf[i] && isspace(buf[i]); i++)
 845                         ; /* do nothing */
 846                 if (buf[i] == '[') {
 847                         /* it's a section */
 848                         int j = 0, dot = 0;
 849                         for (i++; buf[i] && buf[i] != ']'; i++) {
 850                                 if (!dot && isspace(buf[i])) {
 851                                         dot = 1;
 852                                         if (old_name[j++] != '.')
 853                                                 break;
 854                                         for (i++; isspace(buf[i]); i++)
 855                                                 ; /* do nothing */
 856                                         if (buf[i] != '"')
 857                                                 break;
 858                                         continue;
 859                                 }
 860                                 if (buf[i] == '\\' && dot)
 861                                         i++;
 862                                 else if (buf[i] == '"' && dot) {
 863                                         for (i++; isspace(buf[i]); i++)
 864                                                 ; /* do_nothing */
 865                                         break;
 866                                 }
 867                                 if (buf[i] != old_name[j++])
 868                                         break;
 869                         }
 870                         if (buf[i] == ']') {
 871                                 /* old_name matches */
 872                                 ret++;
 873                                 store.baselen = strlen(new_name);
 874                                 if (!store_write_section(out_fd, new_name)) {
 875                                         ret = write_error();
 876                                         goto out;
 877                                 }
 878                                 continue;
 879                         }
 880                 }
 881                 length = strlen(buf);
 882                 if (write_in_full(out_fd, buf, length) != length) {
 883                         ret = write_error();
 884                         goto out;
 885                 }
 886         }
 887         fclose(config_file);
 888         if (close(out_fd) || commit_lock_file(lock) < 0)
 889                         ret = error("Cannot commit config file!");
 890  out:
 891         free(config_filename);
 892         return ret;
 893 }
 894