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.symlinks")) {
 273                 has_symlinks = git_config_bool(var, value);
 274                 return 0;
 275         }
 276
 277         if (!strcmp(var, "core.bare")) {
 278                 is_bare_repository_cfg = git_config_bool(var, value);
 279                 return 0;
 280         }
 281
 282         if (!strcmp(var, "core.ignorestat")) {
 283                 assume_unchanged = git_config_bool(var, value);
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "core.prefersymlinkrefs")) {
 288                 prefer_symlink_refs = git_config_bool(var, value);
 289                 return 0;
 290         }
 291
 292         if (!strcmp(var, "core.logallrefupdates")) {
 293                 log_all_ref_updates = git_config_bool(var, value);
 294                 return 0;
 295         }
 296
 297         if (!strcmp(var, "core.warnambiguousrefs")) {
 298                 warn_ambiguous_refs = git_config_bool(var, value);
 299                 return 0;
 300         }
 301
 302         if (!strcmp(var, "core.legacyheaders")) {
 303                 use_legacy_headers = git_config_bool(var, value);
 304                 return 0;
 305         }
 306
 307         if (!strcmp(var, "core.compression")) {
 308                 int level = git_config_int(var, value);
 309                 if (level == -1)
 310                         level = Z_DEFAULT_COMPRESSION;
 311                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 312                         die("bad zlib compression level %d", level);
 313                 zlib_compression_level = level;
 314                 return 0;
 315         }
 316
 317         if (!strcmp(var, "core.packedgitwindowsize")) {
 318                 int pgsz_x2 = getpagesize() * 2;
 319                 packed_git_window_size = git_config_int(var, value);
 320
 321                 /* This value must be multiple of (pagesize * 2) */
 322                 packed_git_window_size /= pgsz_x2;
 323                 if (packed_git_window_size < 1)
 324                         packed_git_window_size = 1;
 325                 packed_git_window_size *= pgsz_x2;
 326                 return 0;
 327         }
 328
 329         if (!strcmp(var, "core.packedgitlimit")) {
 330                 packed_git_limit = git_config_int(var, value);
 331                 return 0;
 332         }
 333
 334         if (!strcmp(var, "core.autocrlf")) {
 335                 if (value && !strcasecmp(value, "input")) {
 336                         auto_crlf = -1;
 337                         return 0;
 338                 }
 339                 auto_crlf = git_config_bool(var, value);
 340                 return 0;
 341         }
 342
 343         if (!strcmp(var, "user.name")) {
 344                 strlcpy(git_default_name, value, sizeof(git_default_name));
 345                 return 0;
 346         }
 347
 348         if (!strcmp(var, "user.email")) {
 349                 strlcpy(git_default_email, value, sizeof(git_default_email));
 350                 return 0;
 351         }
 352
 353         if (!strcmp(var, "i18n.commitencoding")) {
 354                 git_commit_encoding = strdup(value);
 355                 return 0;
 356         }
 357
 358         if (!strcmp(var, "i18n.logoutputencoding")) {
 359                 git_log_output_encoding = strdup(value);
 360                 return 0;
 361         }
 362
 363
 364         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 365                 pager_use_color = git_config_bool(var,value);
 366                 return 0;
 367         }
 368
 369         /* Add other config variables here and to Documentation/config.txt. */
 370         return 0;
 371 }
 372
 373 int git_config_from_file(config_fn_t fn, const char *filename)
 374 {
 375         int ret;
 376         FILE *f = fopen(filename, "r");
 377
 378         ret = -1;
 379         if (f) {
 380                 config_file = f;
 381                 config_file_name = filename;
 382                 config_linenr = 1;
 383                 ret = git_parse_file(fn);
 384                 fclose(f);
 385                 config_file_name = NULL;
 386         }
 387         return ret;
 388 }
 389
 390 int git_config(config_fn_t fn)
 391 {
 392         int ret = 0;
 393         char *repo_config = NULL;
 394         const char *home = NULL, *filename;
 395
 396         /* $GIT_CONFIG makes git read _only_ the given config file,
 397          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 398          * global config file, the same way it would the per-repository
 399          * config file otherwise. */
 400         filename = getenv(CONFIG_ENVIRONMENT);
 401         if (!filename) {
 402                 if (!access(ETC_GITCONFIG, R_OK))
 403                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 404                 home = getenv("HOME");
 405                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 406                 if (!filename)
 407                         filename = repo_config = xstrdup(git_path("config"));
 408         }
 409
 410         if (home) {
 411                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 412                 if (!access(user_config, R_OK))
 413                         ret = git_config_from_file(fn, user_config);
 414                 free(user_config);
 415         }
 416
 417         ret += git_config_from_file(fn, filename);
 418         free(repo_config);
 419         return ret;
 420 }
 421
 422 /*
 423  * Find all the stuff for git_config_set() below.
 424  */
 425
 426 #define MAX_MATCHES 512
 427
 428 static struct {
 429         int baselen;
 430         char* key;
 431         int do_not_match;
 432         regex_t* value_regex;
 433         int multi_replace;
 434         size_t offset[MAX_MATCHES];
 435         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 436         int seen;
 437 } store;
 438
 439 static int matches(const char* key, const char* value)
 440 {
 441         return !strcmp(key, store.key) &&
 442                 (store.value_regex == NULL ||
 443                  (store.do_not_match ^
 444                   !regexec(store.value_regex, value, 0, NULL, 0)));
 445 }
 446
 447 static int store_aux(const char* key, const char* value)
 448 {
 449         switch (store.state) {
 450         case KEY_SEEN:
 451                 if (matches(key, value)) {
 452                         if (store.seen == 1 && store.multi_replace == 0) {
 453                                 fprintf(stderr,
 454                                         "Warning: %s has multiple values\n",
 455                                         key);
 456                         } else if (store.seen >= MAX_MATCHES) {
 457                                 fprintf(stderr, "Too many matches\n");
 458                                 return 1;
 459                         }
 460
 461                         store.offset[store.seen] = ftell(config_file);
 462                         store.seen++;
 463                 }
 464                 break;
 465         case SECTION_SEEN:
 466                 if (strncmp(key, store.key, store.baselen+1)) {
 467                         store.state = SECTION_END_SEEN;
 468                         break;
 469                 } else
 470                         /* do not increment matches: this is no match */
 471                         store.offset[store.seen] = ftell(config_file);
 472                 /* fallthru */
 473         case SECTION_END_SEEN:
 474         case START:
 475                 if (matches(key, value)) {
 476                         store.offset[store.seen] = ftell(config_file);
 477                         store.state = KEY_SEEN;
 478                         store.seen++;
 479                 } else {
 480                         if (strrchr(key, '.') - key == store.baselen &&
 481                               !strncmp(key, store.key, store.baselen)) {
 482                                         store.state = SECTION_SEEN;
 483                                         store.offset[store.seen] = ftell(config_file);
 484                         }
 485                 }
 486         }
 487         return 0;
 488 }
 489
 490 static int write_error()
 491 {
 492         fprintf(stderr, "Failed to write new configuration file\n");
 493
 494         /* Same error code as "failed to rename". */
 495         return 4;
 496 }
 497
 498 static int store_write_section(int fd, const char* key)
 499 {
 500         const char *dot = strchr(key, '.');
 501         int len1 = store.baselen, len2 = -1;
 502
 503         dot = strchr(key, '.');
 504         if (dot) {
 505                 int dotlen = dot - key;
 506                 if (dotlen < len1) {
 507                         len2 = len1 - dotlen - 1;
 508                         len1 = dotlen;
 509                 }
 510         }
 511
 512         if (write_in_full(fd, "[", 1) != 1 ||
 513             write_in_full(fd, key, len1) != len1)
 514                 return 0;
 515         if (len2 >= 0) {
 516                 if (write_in_full(fd, " \"", 2) != 2)
 517                         return 0;
 518                 while (--len2 >= 0) {
 519                         unsigned char c = *++dot;
 520                         if (c == '"')
 521                                 if (write_in_full(fd, "\\", 1) != 1)
 522                                         return 0;
 523                         if (write_in_full(fd, &c, 1) != 1)
 524                                 return 0;
 525                 }
 526                 if (write_in_full(fd, "\"", 1) != 1)
 527                         return 0;
 528         }
 529         if (write_in_full(fd, "]\n", 2) != 2)
 530                 return 0;
 531
 532         return 1;
 533 }
 534
 535 static int store_write_pair(int fd, const char* key, const char* value)
 536 {
 537         int i;
 538         int length = strlen(key+store.baselen+1);
 539         int quote = 0;
 540
 541         /* Check to see if the value needs to be quoted. */
 542         if (value[0] == ' ')
 543                 quote = 1;
 544         for (i = 0; value[i]; i++)
 545                 if (value[i] == ';' || value[i] == '#')
 546                         quote = 1;
 547         if (value[i-1] == ' ')
 548                 quote = 1;
 549
 550         if (write_in_full(fd, "\t", 1) != 1 ||
 551             write_in_full(fd, key+store.baselen+1, length) != length ||
 552             write_in_full(fd, " = ", 3) != 3)
 553                 return 0;
 554         if (quote && write_in_full(fd, "\"", 1) != 1)
 555                 return 0;
 556         for (i = 0; value[i]; i++)
 557                 switch (value[i]) {
 558                 case '\n':
 559                         if (write_in_full(fd, "\\n", 2) != 2)
 560                                 return 0;
 561                         break;
 562                 case '\t':
 563                         if (write_in_full(fd, "\\t", 2) != 2)
 564                                 return 0;
 565                         break;
 566                 case '"':
 567                 case '\\':
 568                         if (write_in_full(fd, "\\", 1) != 1)
 569                                 return 0;
 570                 default:
 571                         if (write_in_full(fd, value+i, 1) != 1)
 572                                 return 0;
 573                         break;
 574                 }
 575         if (quote && write_in_full(fd, "\"", 1) != 1)
 576                 return 0;
 577         if (write_in_full(fd, "\n", 1) != 1)
 578                 return 0;
 579         return 1;
 580 }
 581
 582 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 583         size_t offset_, int* found_bracket)
 584 {
 585         size_t equal_offset = size, bracket_offset = size;
 586         ssize_t offset;
 587
 588         for (offset = offset_-2; offset > 0
 589                         && contents[offset] != '\n'; offset--)
 590                 switch (contents[offset]) {
 591                         case '=': equal_offset = offset; break;
 592                         case ']': bracket_offset = offset; break;
 593                 }
 594         if (bracket_offset < equal_offset) {
 595                 *found_bracket = 1;
 596                 offset = bracket_offset+1;
 597         } else
 598                 offset++;
 599
 600         return offset;
 601 }
 602
 603 int git_config_set(const char* key, const char* value)
 604 {
 605         return git_config_set_multivar(key, value, NULL, 0);
 606 }
 607
 608 /*
 609  * If value==NULL, unset in (remove from) config,
 610  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 611  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 612  *     else all matching key/values (regardless how many) are removed,
 613  *     before the new pair is written.
 614  *
 615  * Returns 0 on success.
 616  *
 617  * This function does this:
 618  *
 619  * - it locks the config file by creating ".git/config.lock"
 620  *
 621  * - it then parses the config using store_aux() as validator to find
 622  *   the position on the key/value pair to replace. If it is to be unset,
 623  *   it must be found exactly once.
 624  *
 625  * - the config file is mmap()ed and the part before the match (if any) is
 626  *   written to the lock file, then the changed part and the rest.
 627  *
 628  * - the config file is removed and the lock file rename()d to it.
 629  *
 630  */
 631 int git_config_set_multivar(const char* key, const char* value,
 632         const char* value_regex, int multi_replace)
 633 {
 634         int i, dot;
 635         int fd = -1, in_fd;
 636         int ret;
 637         char* config_filename;
 638         char* lock_file;
 639         const char* last_dot = strrchr(key, '.');
 640
 641         config_filename = getenv(CONFIG_ENVIRONMENT);
 642         if (!config_filename) {
 643                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 644                 if (!config_filename)
 645                         config_filename  = git_path("config");
 646         }
 647         config_filename = xstrdup(config_filename);
 648         lock_file = xstrdup(mkpath("%s.lock", config_filename));
 649
 650         /*
 651          * Since "key" actually contains the section name and the real
 652          * key name separated by a dot, we have to know where the dot is.
 653          */
 654
 655         if (last_dot == NULL) {
 656                 fprintf(stderr, "key does not contain a section: %s\n", key);
 657                 ret = 2;
 658                 goto out_free;
 659         }
 660         store.baselen = last_dot - key;
 661
 662         store.multi_replace = multi_replace;
 663
 664         /*
 665          * Validate the key and while at it, lower case it for matching.
 666          */
 667         store.key = xmalloc(strlen(key) + 1);
 668         dot = 0;
 669         for (i = 0; key[i]; i++) {
 670                 unsigned char c = key[i];
 671                 if (c == '.')
 672                         dot = 1;
 673                 /* Leave the extended basename untouched.. */
 674                 if (!dot || i > store.baselen) {
 675                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 676                                 fprintf(stderr, "invalid key: %s\n", key);
 677                                 free(store.key);
 678                                 ret = 1;
 679                                 goto out_free;
 680                         }
 681                         c = tolower(c);
 682                 } else if (c == '\n') {
 683                         fprintf(stderr, "invalid key (newline): %s\n", key);
 684                         free(store.key);
 685                         ret = 1;
 686                         goto out_free;
 687                 }
 688                 store.key[i] = c;
 689         }
 690         store.key[i] = 0;
 691
 692         /*
 693          * The lock_file serves a purpose in addition to locking: the new
 694          * contents of .git/config will be written into it.
 695          */
 696         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 697         if (fd < 0 || adjust_shared_perm(lock_file)) {
 698                 fprintf(stderr, "could not lock config file\n");
 699                 free(store.key);
 700                 ret = -1;
 701                 goto out_free;
 702         }
 703
 704         /*
 705          * If .git/config does not exist yet, write a minimal version.
 706          */
 707         in_fd = open(config_filename, O_RDONLY);
 708         if ( in_fd < 0 ) {
 709                 free(store.key);
 710
 711                 if ( ENOENT != errno ) {
 712                         error("opening %s: %s", config_filename,
 713                               strerror(errno));
 714                         ret = 3; /* same as "invalid config file" */
 715                         goto out_free;
 716                 }
 717                 /* if nothing to unset, error out */
 718                 if (value == NULL) {
 719                         ret = 5;
 720                         goto out_free;
 721                 }
 722
 723                 store.key = (char*)key;
 724                 if (!store_write_section(fd, key) ||
 725                     !store_write_pair(fd, key, value))
 726                         goto write_err_out;
 727         } else {
 728                 struct stat st;
 729                 char* contents;
 730                 size_t contents_sz, copy_begin, copy_end;
 731                 int i, new_line = 0;
 732
 733                 if (value_regex == NULL)
 734                         store.value_regex = NULL;
 735                 else {
 736                         if (value_regex[0] == '!') {
 737                                 store.do_not_match = 1;
 738                                 value_regex++;
 739                         } else
 740                                 store.do_not_match = 0;
 741
 742                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 743                         if (regcomp(store.value_regex, value_regex,
 744                                         REG_EXTENDED)) {
 745                                 fprintf(stderr, "Invalid pattern: %s\n",
 746                                         value_regex);
 747                                 free(store.value_regex);
 748                                 ret = 6;
 749                                 goto out_free;
 750                         }
 751                 }
 752
 753                 store.offset[0] = 0;
 754                 store.state = START;
 755                 store.seen = 0;
 756
 757                 /*
 758                  * After this, store.offset will contain the *end* offset
 759                  * of the last match, or remain at 0 if no match was found.
 760                  * As a side effect, we make sure to transform only a valid
 761                  * existing config file.
 762                  */
 763                 if (git_config_from_file(store_aux, config_filename)) {
 764                         fprintf(stderr, "invalid config file\n");
 765                         free(store.key);
 766                         if (store.value_regex != NULL) {
 767                                 regfree(store.value_regex);
 768                                 free(store.value_regex);
 769                         }
 770                         ret = 3;
 771                         goto out_free;
 772                 }
 773
 774                 free(store.key);
 775                 if (store.value_regex != NULL) {
 776                         regfree(store.value_regex);
 777                         free(store.value_regex);
 778                 }
 779
 780                 /* if nothing to unset, or too many matches, error out */
 781                 if ((store.seen == 0 && value == NULL) ||
 782                                 (store.seen > 1 && multi_replace == 0)) {
 783                         ret = 5;
 784                         goto out_free;
 785                 }
 786
 787                 fstat(in_fd, &st);
 788                 contents_sz = xsize_t(st.st_size);
 789                 contents = xmmap(NULL, contents_sz, PROT_READ,
 790                         MAP_PRIVATE, in_fd, 0);
 791                 close(in_fd);
 792
 793                 if (store.seen == 0)
 794                         store.seen = 1;
 795
 796                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 797                         if (store.offset[i] == 0) {
 798                                 store.offset[i] = copy_end = contents_sz;
 799                         } else if (store.state != KEY_SEEN) {
 800                                 copy_end = store.offset[i];
 801                         } else
 802                                 copy_end = find_beginning_of_line(
 803                                         contents, contents_sz,
 804                                         store.offset[i]-2, &new_line);
 805
 806                         /* write the first part of the config */
 807                         if (copy_end > copy_begin) {
 808                                 if (write_in_full(fd, contents + copy_begin,
 809                                                   copy_end - copy_begin) <
 810                                     copy_end - copy_begin)
 811                                         goto write_err_out;
 812                                 if (new_line &&
 813                                     write_in_full(fd, "\n", 1) != 1)
 814                                         goto write_err_out;
 815                         }
 816                         copy_begin = store.offset[i];
 817                 }
 818
 819                 /* write the pair (value == NULL means unset) */
 820                 if (value != NULL) {
 821                         if (store.state == START) {
 822                                 if (!store_write_section(fd, key))
 823                                         goto write_err_out;
 824                         }
 825                         if (!store_write_pair(fd, key, value))
 826                                 goto write_err_out;
 827                 }
 828
 829                 /* write the rest of the config */
 830                 if (copy_begin < contents_sz)
 831                         if (write_in_full(fd, contents + copy_begin,
 832                                           contents_sz - copy_begin) <
 833                             contents_sz - copy_begin)
 834                                 goto write_err_out;
 835
 836                 munmap(contents, contents_sz);
 837                 unlink(config_filename);
 838         }
 839
 840         if (rename(lock_file, config_filename) < 0) {
 841                 fprintf(stderr, "Could not rename the lock file?\n");
 842                 ret = 4;
 843                 goto out_free;
 844         }
 845
 846         ret = 0;
 847
 848 out_free:
 849         if (0 <= fd)
 850                 close(fd);
 851         free(config_filename);
 852         if (lock_file) {
 853                 unlink(lock_file);
 854                 free(lock_file);
 855         }
 856         return ret;
 857
 858 write_err_out:
 859         ret = write_error();
 860         goto out_free;
 861
 862 }
 863
 864 static int section_name_match (const char *buf, const char *name)
 865 {
 866         int i = 0, j = 0, dot = 0;
 867         for (; buf[i] && buf[i] != ']'; i++) {
 868                 if (!dot && isspace(buf[i])) {
 869                         dot = 1;
 870                         if (name[j++] != '.')
 871                                 break;
 872                         for (i++; isspace(buf[i]); i++)
 873                                 ; /* do nothing */
 874                         if (buf[i] != '"')
 875                                 break;
 876                         continue;
 877                 }
 878                 if (buf[i] == '\\' && dot)
 879                         i++;
 880                 else if (buf[i] == '"' && dot) {
 881                         for (i++; isspace(buf[i]); i++)
 882                                 ; /* do_nothing */
 883                         break;
 884                 }
 885                 if (buf[i] != name[j++])
 886                         break;
 887         }
 888         return (buf[i] == ']' && name[j] == 0);
 889 }
 890
 891 /* if new_name == NULL, the section is removed instead */
 892 int git_config_rename_section(const char *old_name, const char *new_name)
 893 {
 894         int ret = 0, remove = 0;
 895         char *config_filename;
 896         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 897         int out_fd;
 898         char buf[1024];
 899
 900         config_filename = getenv(CONFIG_ENVIRONMENT);
 901         if (!config_filename) {
 902                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 903                 if (!config_filename)
 904                         config_filename  = git_path("config");
 905         }
 906         config_filename = xstrdup(config_filename);
 907         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 908         if (out_fd < 0) {
 909                 ret = error("Could not lock config file!");
 910                 goto out;
 911         }
 912
 913         if (!(config_file = fopen(config_filename, "rb"))) {
 914                 ret = error("Could not open config file!");
 915                 goto out;
 916         }
 917
 918         while (fgets(buf, sizeof(buf), config_file)) {
 919                 int i;
 920                 int length;
 921                 for (i = 0; buf[i] && isspace(buf[i]); i++)
 922                         ; /* do nothing */
 923                 if (buf[i] == '[') {
 924                         /* it's a section */
 925                         if (section_name_match (&buf[i+1], old_name)) {
 926                                 ret++;
 927                                 if (new_name == NULL) {
 928                                         remove = 1;
 929                                         continue;
 930                                 }
 931                                 store.baselen = strlen(new_name);
 932                                 if (!store_write_section(out_fd, new_name)) {
 933                                         ret = write_error();
 934                                         goto out;
 935                                 }
 936                                 continue;
 937                         }
 938                         remove = 0;
 939                 }
 940                 if (remove)
 941                         continue;
 942                 length = strlen(buf);
 943                 if (write_in_full(out_fd, buf, length) != length) {
 944                         ret = write_error();
 945                         goto out;
 946                 }
 947         }
 948         fclose(config_file);
 949         if (close(out_fd) || commit_lock_file(lock) < 0)
 950                         ret = error("Cannot commit config file!");
 951  out:
 952         free(config_filename);
 953         return ret;
 954 }
 955