git.oblomov.eu Git - git/blob - 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.bare")) {
 273                 is_bare_repository_cfg = git_config_bool(var, value);
 274                 return 0;
 275         }
 276
 277         if (!strcmp(var, "core.ignorestat")) {
 278                 assume_unchanged = git_config_bool(var, value);
 279                 return 0;
 280         }
 281
 282         if (!strcmp(var, "core.prefersymlinkrefs")) {
 283                 prefer_symlink_refs = git_config_bool(var, value);
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "core.logallrefupdates")) {
 288                 log_all_ref_updates = git_config_bool(var, value);
 289                 return 0;
 290         }
 291
 292         if (!strcmp(var, "core.warnambiguousrefs")) {
 293                 warn_ambiguous_refs = git_config_bool(var, value);
 294                 return 0;
 295         }
 296
 297         if (!strcmp(var, "core.legacyheaders")) {
 298                 use_legacy_headers = git_config_bool(var, value);
 299                 return 0;
 300         }
 301
 302         if (!strcmp(var, "core.compression")) {
 303                 int level = git_config_int(var, value);
 304                 if (level == -1)
 305                         level = Z_DEFAULT_COMPRESSION;
 306                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 307                         die("bad zlib compression level %d", level);
 308                 zlib_compression_level = level;
 309                 return 0;
 310         }
 311
 312         if (!strcmp(var, "core.packedgitwindowsize")) {
 313                 int pgsz_x2 = getpagesize() * 2;
 314                 packed_git_window_size = git_config_int(var, value);
 315
 316                 /* This value must be multiple of (pagesize * 2) */
 317                 packed_git_window_size /= pgsz_x2;
 318                 if (packed_git_window_size < 1)
 319                         packed_git_window_size = 1;
 320                 packed_git_window_size *= pgsz_x2;
 321                 return 0;
 322         }
 323
 324         if (!strcmp(var, "core.packedgitlimit")) {
 325                 packed_git_limit = git_config_int(var, value);
 326                 return 0;
 327         }
 328
 329         if (!strcmp(var, "core.autocrlf")) {
 330                 if (value && !strcasecmp(value, "input")) {
 331                         auto_crlf = -1;
 332                         return 0;
 333                 }
 334                 auto_crlf = git_config_bool(var, value);
 335                 return 0;
 336         }
 337
 338         if (!strcmp(var, "user.name")) {
 339                 strlcpy(git_default_name, value, sizeof(git_default_name));
 340                 return 0;
 341         }
 342
 343         if (!strcmp(var, "user.email")) {
 344                 strlcpy(git_default_email, value, sizeof(git_default_email));
 345                 return 0;
 346         }
 347
 348         if (!strcmp(var, "i18n.commitencoding")) {
 349                 git_commit_encoding = strdup(value);
 350                 return 0;
 351         }
 352
 353         if (!strcmp(var, "i18n.logoutputencoding")) {
 354                 git_log_output_encoding = strdup(value);
 355                 return 0;
 356         }
 357
 358
 359         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 360                 pager_use_color = git_config_bool(var,value);
 361                 return 0;
 362         }
 363
 364         /* Add other config variables here and to Documentation/config.txt. */
 365         return 0;
 366 }
 367
 368 int git_config_from_file(config_fn_t fn, const char *filename)
 369 {
 370         int ret;
 371         FILE *f = fopen(filename, "r");
 372
 373         ret = -1;
 374         if (f) {
 375                 config_file = f;
 376                 config_file_name = filename;
 377                 config_linenr = 1;
 378                 ret = git_parse_file(fn);
 379                 fclose(f);
 380                 config_file_name = NULL;
 381         }
 382         return ret;
 383 }
 384
 385 int git_config(config_fn_t fn)
 386 {
 387         int ret = 0;
 388         char *repo_config = NULL;
 389         const char *home = NULL, *filename;
 390
 391         /* $GIT_CONFIG makes git read _only_ the given config file,
 392          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 393          * global config file, the same way it would the per-repository
 394          * config file otherwise. */
 395         filename = getenv(CONFIG_ENVIRONMENT);
 396         if (!filename) {
 397                 if (!access(ETC_GITCONFIG, R_OK))
 398                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 399                 home = getenv("HOME");
 400                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 401                 if (!filename)
 402                         filename = repo_config = xstrdup(git_path("config"));
 403         }
 404
 405         if (home) {
 406                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 407                 if (!access(user_config, R_OK))
 408                         ret = git_config_from_file(fn, user_config);
 409                 free(user_config);
 410         }
 411
 412         ret += git_config_from_file(fn, filename);
 413         free(repo_config);
 414         return ret;
 415 }
 416
 417 /*
 418  * Find all the stuff for git_config_set() below.
 419  */
 420
 421 #define MAX_MATCHES 512
 422
 423 static struct {
 424         int baselen;
 425         char* key;
 426         int do_not_match;
 427         regex_t* value_regex;
 428         int multi_replace;
 429         off_t offset[MAX_MATCHES];
 430         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 431         int seen;
 432 } store;
 433
 434 static int matches(const char* key, const char* value)
 435 {
 436         return !strcmp(key, store.key) &&
 437                 (store.value_regex == NULL ||
 438                  (store.do_not_match ^
 439                   !regexec(store.value_regex, value, 0, NULL, 0)));
 440 }
 441
 442 static int store_aux(const char* key, const char* value)
 443 {
 444         switch (store.state) {
 445         case KEY_SEEN:
 446                 if (matches(key, value)) {
 447                         if (store.seen == 1 && store.multi_replace == 0) {
 448                                 fprintf(stderr,
 449                                         "Warning: %s has multiple values\n",
 450                                         key);
 451                         } else if (store.seen >= MAX_MATCHES) {
 452                                 fprintf(stderr, "Too many matches\n");
 453                                 return 1;
 454                         }
 455
 456                         store.offset[store.seen] = ftell(config_file);
 457                         store.seen++;
 458                 }
 459                 break;
 460         case SECTION_SEEN:
 461                 if (strncmp(key, store.key, store.baselen+1)) {
 462                         store.state = SECTION_END_SEEN;
 463                         break;
 464                 } else
 465                         /* do not increment matches: this is no match */
 466                         store.offset[store.seen] = ftell(config_file);
 467                 /* fallthru */
 468         case SECTION_END_SEEN:
 469         case START:
 470                 if (matches(key, value)) {
 471                         store.offset[store.seen] = ftell(config_file);
 472                         store.state = KEY_SEEN;
 473                         store.seen++;
 474                 } else {
 475                         if (strrchr(key, '.') - key == store.baselen &&
 476                               !strncmp(key, store.key, store.baselen)) {
 477                                         store.state = SECTION_SEEN;
 478                                         store.offset[store.seen] = ftell(config_file);
 479                         }
 480                 }
 481         }
 482         return 0;
 483 }
 484
 485 static int write_error()
 486 {
 487         fprintf(stderr, "Failed to write new configuration file\n");
 488
 489         /* Same error code as "failed to rename". */
 490         return 4;
 491 }
 492
 493 static int store_write_section(int fd, const char* key)
 494 {
 495         const char *dot = strchr(key, '.');
 496         int len1 = store.baselen, len2 = -1;
 497
 498         dot = strchr(key, '.');
 499         if (dot) {
 500                 int dotlen = dot - key;
 501                 if (dotlen < len1) {
 502                         len2 = len1 - dotlen - 1;
 503                         len1 = dotlen;
 504                 }
 505         }
 506
 507         if (write_in_full(fd, "[", 1) != 1 ||
 508             write_in_full(fd, key, len1) != len1)
 509                 return 0;
 510         if (len2 >= 0) {
 511                 if (write_in_full(fd, " \"", 2) != 2)
 512                         return 0;
 513                 while (--len2 >= 0) {
 514                         unsigned char c = *++dot;
 515                         if (c == '"')
 516                                 if (write_in_full(fd, "\\", 1) != 1)
 517                                         return 0;
 518                         if (write_in_full(fd, &c, 1) != 1)
 519                                 return 0;
 520                 }
 521                 if (write_in_full(fd, "\"", 1) != 1)
 522                         return 0;
 523         }
 524         if (write_in_full(fd, "]\n", 2) != 2)
 525                 return 0;
 526
 527         return 1;
 528 }
 529
 530 static int store_write_pair(int fd, const char* key, const char* value)
 531 {
 532         int i;
 533         int length = strlen(key+store.baselen+1);
 534         int quote = 0;
 535
 536         /* Check to see if the value needs to be quoted. */
 537         if (value[0] == ' ')
 538                 quote = 1;
 539         for (i = 0; value[i]; i++)
 540                 if (value[i] == ';' || value[i] == '#')
 541                         quote = 1;
 542         if (value[i-1] == ' ')
 543                 quote = 1;
 544
 545         if (write_in_full(fd, "\t", 1) != 1 ||
 546             write_in_full(fd, key+store.baselen+1, length) != length ||
 547             write_in_full(fd, " = ", 3) != 3)
 548                 return 0;
 549         if (quote && write_in_full(fd, "\"", 1) != 1)
 550                 return 0;
 551         for (i = 0; value[i]; i++)
 552                 switch (value[i]) {
 553                 case '\n':
 554                         if (write_in_full(fd, "\\n", 2) != 2)
 555                                 return 0;
 556                         break;
 557                 case '\t':
 558                         if (write_in_full(fd, "\\t", 2) != 2)
 559                                 return 0;
 560                         break;
 561                 case '"':
 562                 case '\\':
 563                         if (write_in_full(fd, "\\", 1) != 1)
 564                                 return 0;
 565                 default:
 566                         if (write_in_full(fd, value+i, 1) != 1)
 567                                 return 0;
 568                         break;
 569                 }
 570         if (quote && write_in_full(fd, "\"", 1) != 1)
 571                 return 0;
 572         if (write_in_full(fd, "\n", 1) != 1)
 573                 return 0;
 574         return 1;
 575 }
 576
 577 static int find_beginning_of_line(const char* contents, int size,
 578         int offset_, int* found_bracket)
 579 {
 580         int equal_offset = size, bracket_offset = size;
 581         int offset;
 582
 583         for (offset = offset_-2; offset > 0
 584                         && contents[offset] != '\n'; offset--)
 585                 switch (contents[offset]) {
 586                         case '=': equal_offset = offset; break;
 587                         case ']': bracket_offset = offset; break;
 588                 }
 589         if (bracket_offset < equal_offset) {
 590                 *found_bracket = 1;
 591                 offset = bracket_offset+1;
 592         } else
 593                 offset++;
 594
 595         return offset;
 596 }
 597
 598 int git_config_set(const char* key, const char* value)
 599 {
 600         return git_config_set_multivar(key, value, NULL, 0);
 601 }
 602
 603 /*
 604  * If value==NULL, unset in (remove from) config,
 605  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 606  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 607  *     else all matching key/values (regardless how many) are removed,
 608  *     before the new pair is written.
 609  *
 610  * Returns 0 on success.
 611  *
 612  * This function does this:
 613  *
 614  * - it locks the config file by creating ".git/config.lock"
 615  *
 616  * - it then parses the config using store_aux() as validator to find
 617  *   the position on the key/value pair to replace. If it is to be unset,
 618  *   it must be found exactly once.
 619  *
 620  * - the config file is mmap()ed and the part before the match (if any) is
 621  *   written to the lock file, then the changed part and the rest.
 622  *
 623  * - the config file is removed and the lock file rename()d to it.
 624  *
 625  */
 626 int git_config_set_multivar(const char* key, const char* value,
 627         const char* value_regex, int multi_replace)
 628 {
 629         int i, dot;
 630         int fd = -1, in_fd;
 631         int ret;
 632         char* config_filename;
 633         char* lock_file;
 634         const char* last_dot = strrchr(key, '.');
 635
 636         config_filename = getenv(CONFIG_ENVIRONMENT);
 637         if (!config_filename) {
 638                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 639                 if (!config_filename)
 640                         config_filename  = git_path("config");
 641         }
 642         config_filename = xstrdup(config_filename);
 643         lock_file = xstrdup(mkpath("%s.lock", config_filename));
 644
 645         /*
 646          * Since "key" actually contains the section name and the real
 647          * key name separated by a dot, we have to know where the dot is.
 648          */
 649
 650         if (last_dot == NULL) {
 651                 fprintf(stderr, "key does not contain a section: %s\n", key);
 652                 ret = 2;
 653                 goto out_free;
 654         }
 655         store.baselen = last_dot - key;
 656
 657         store.multi_replace = multi_replace;
 658
 659         /*
 660          * Validate the key and while at it, lower case it for matching.
 661          */
 662         store.key = xmalloc(strlen(key) + 1);
 663         dot = 0;
 664         for (i = 0; key[i]; i++) {
 665                 unsigned char c = key[i];
 666                 if (c == '.')
 667                         dot = 1;
 668                 /* Leave the extended basename untouched.. */
 669                 if (!dot || i > store.baselen) {
 670                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 671                                 fprintf(stderr, "invalid key: %s\n", key);
 672                                 free(store.key);
 673                                 ret = 1;
 674                                 goto out_free;
 675                         }
 676                         c = tolower(c);
 677                 } else if (c == '\n') {
 678                         fprintf(stderr, "invalid key (newline): %s\n", key);
 679                         free(store.key);
 680                         ret = 1;
 681                         goto out_free;
 682                 }
 683                 store.key[i] = c;
 684         }
 685         store.key[i] = 0;
 686
 687         /*
 688          * The lock_file serves a purpose in addition to locking: the new
 689          * contents of .git/config will be written into it.
 690          */
 691         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 692         if (fd < 0 || adjust_shared_perm(lock_file)) {
 693                 fprintf(stderr, "could not lock config file\n");
 694                 free(store.key);
 695                 ret = -1;
 696                 goto out_free;
 697         }
 698
 699         /*
 700          * If .git/config does not exist yet, write a minimal version.
 701          */
 702         in_fd = open(config_filename, O_RDONLY);
 703         if ( in_fd < 0 ) {
 704                 free(store.key);
 705
 706                 if ( ENOENT != errno ) {
 707                         error("opening %s: %s", config_filename,
 708                               strerror(errno));
 709                         ret = 3; /* same as "invalid config file" */
 710                         goto out_free;
 711                 }
 712                 /* if nothing to unset, error out */
 713                 if (value == NULL) {
 714                         ret = 5;
 715                         goto out_free;
 716                 }
 717
 718                 store.key = (char*)key;
 719                 if (!store_write_section(fd, key) ||
 720                     !store_write_pair(fd, key, value))
 721                         goto write_err_out;
 722         } else {
 723                 struct stat st;
 724                 char* contents;
 725                 int i, copy_begin, copy_end, new_line = 0;
 726
 727                 if (value_regex == NULL)
 728                         store.value_regex = NULL;
 729                 else {
 730                         if (value_regex[0] == '!') {
 731                                 store.do_not_match = 1;
 732                                 value_regex++;
 733                         } else
 734                                 store.do_not_match = 0;
 735
 736                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 737                         if (regcomp(store.value_regex, value_regex,
 738                                         REG_EXTENDED)) {
 739                                 fprintf(stderr, "Invalid pattern: %s\n",
 740                                         value_regex);
 741                                 free(store.value_regex);
 742                                 ret = 6;
 743                                 goto out_free;
 744                         }
 745                 }
 746
 747                 store.offset[0] = 0;
 748                 store.state = START;
 749                 store.seen = 0;
 750
 751                 /*
 752                  * After this, store.offset will contain the *end* offset
 753                  * of the last match, or remain at 0 if no match was found.
 754                  * As a side effect, we make sure to transform only a valid
 755                  * existing config file.
 756                  */
 757                 if (git_config_from_file(store_aux, config_filename)) {
 758                         fprintf(stderr, "invalid config file\n");
 759                         free(store.key);
 760                         if (store.value_regex != NULL) {
 761                                 regfree(store.value_regex);
 762                                 free(store.value_regex);
 763                         }
 764                         ret = 3;
 765                         goto out_free;
 766                 }
 767
 768                 free(store.key);
 769                 if (store.value_regex != NULL) {
 770                         regfree(store.value_regex);
 771                         free(store.value_regex);
 772                 }
 773
 774                 /* if nothing to unset, or too many matches, error out */
 775                 if ((store.seen == 0 && value == NULL) ||
 776                                 (store.seen > 1 && multi_replace == 0)) {
 777                         ret = 5;
 778                         goto out_free;
 779                 }
 780
 781                 fstat(in_fd, &st);
 782                 contents = xmmap(NULL, st.st_size, PROT_READ,
 783                         MAP_PRIVATE, in_fd, 0);
 784                 close(in_fd);
 785
 786                 if (store.seen == 0)
 787                         store.seen = 1;
 788
 789                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 790                         if (store.offset[i] == 0) {
 791                                 store.offset[i] = copy_end = st.st_size;
 792                         } else if (store.state != KEY_SEEN) {
 793                                 copy_end = store.offset[i];
 794                         } else
 795                                 copy_end = find_beginning_of_line(
 796                                         contents, st.st_size,
 797                                         store.offset[i]-2, &new_line);
 798
 799                         /* write the first part of the config */
 800                         if (copy_end > copy_begin) {
 801                                 if (write_in_full(fd, contents + copy_begin,
 802                                                   copy_end - copy_begin) <
 803                                     copy_end - copy_begin)
 804                                         goto write_err_out;
 805                                 if (new_line &&
 806                                     write_in_full(fd, "\n", 1) != 1)
 807                                         goto write_err_out;
 808                         }
 809                         copy_begin = store.offset[i];
 810                 }
 811
 812                 /* write the pair (value == NULL means unset) */
 813                 if (value != NULL) {
 814                         if (store.state == START) {
 815                                 if (!store_write_section(fd, key))
 816                                         goto write_err_out;
 817                         }
 818                         if (!store_write_pair(fd, key, value))
 819                                 goto write_err_out;
 820                 }
 821
 822                 /* write the rest of the config */
 823                 if (copy_begin < st.st_size)
 824                         if (write_in_full(fd, contents + copy_begin,
 825                                           st.st_size - copy_begin) <
 826                             st.st_size - copy_begin)
 827                                 goto write_err_out;
 828
 829                 munmap(contents, st.st_size);
 830                 unlink(config_filename);
 831         }
 832
 833         if (rename(lock_file, config_filename) < 0) {
 834                 fprintf(stderr, "Could not rename the lock file?\n");
 835                 ret = 4;
 836                 goto out_free;
 837         }
 838
 839         ret = 0;
 840
 841 out_free:
 842         if (0 <= fd)
 843                 close(fd);
 844         free(config_filename);
 845         if (lock_file) {
 846                 unlink(lock_file);
 847                 free(lock_file);
 848         }
 849         return ret;
 850
 851 write_err_out:
 852         ret = write_error();
 853         goto out_free;
 854
 855 }
 856
 857 int git_config_rename_section(const char *old_name, const char *new_name)
 858 {
 859         int ret = 0;
 860         char *config_filename;
 861         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 862         int out_fd;
 863         char buf[1024];
 864
 865         config_filename = getenv(CONFIG_ENVIRONMENT);
 866         if (!config_filename) {
 867                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 868                 if (!config_filename)
 869                         config_filename  = git_path("config");
 870         }
 871         config_filename = xstrdup(config_filename);
 872         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 873         if (out_fd < 0) {
 874                 ret = error("Could not lock config file!");
 875                 goto out;
 876         }
 877
 878         if (!(config_file = fopen(config_filename, "rb"))) {
 879                 ret = error("Could not open config file!");
 880                 goto out;
 881         }
 882
 883         while (fgets(buf, sizeof(buf), config_file)) {
 884                 int i;
 885                 int length;
 886                 for (i = 0; buf[i] && isspace(buf[i]); i++)
 887                         ; /* do nothing */
 888                 if (buf[i] == '[') {
 889                         /* it's a section */
 890                         int j = 0, dot = 0;
 891                         for (i++; buf[i] && buf[i] != ']'; i++) {
 892                                 if (!dot && isspace(buf[i])) {
 893                                         dot = 1;
 894                                         if (old_name[j++] != '.')
 895                                                 break;
 896                                         for (i++; isspace(buf[i]); i++)
 897                                                 ; /* do nothing */
 898                                         if (buf[i] != '"')
 899                                                 break;
 900                                         continue;
 901                                 }
 902                                 if (buf[i] == '\\' && dot)
 903                                         i++;
 904                                 else if (buf[i] == '"' && dot) {
 905                                         for (i++; isspace(buf[i]); i++)
 906                                                 ; /* do_nothing */
 907                                         break;
 908                                 }
 909                                 if (buf[i] != old_name[j++])
 910                                         break;
 911                         }
 912                         if (buf[i] == ']' && old_name[j] == 0) {
 913                                 /* old_name matches */
 914                                 ret++;
 915                                 store.baselen = strlen(new_name);
 916                                 if (!store_write_section(out_fd, new_name)) {
 917                                         ret = write_error();
 918                                         goto out;
 919                                 }
 920                                 continue;
 921                         }
 922                 }
 923                 length = strlen(buf);
 924                 if (write_in_full(out_fd, buf, length) != length) {
 925                         ret = write_error();
 926                         goto out;
 927                 }
 928         }
 929         fclose(config_file);
 930         if (close(out_fd) || commit_lock_file(lock) < 0)
 931                         ret = error("Cannot commit config file!");
 932  out:
 933         free(config_filename);
 934         return ret;
 935 }
 936