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 zlib_compression_seen;
  16
  17 static int get_next_char(void)
  18 {
  19         int c;
  20         FILE *f;
  21
  22         c = '\n';
  23         if ((f = config_file) != NULL) {
  24                 c = fgetc(f);
  25                 if (c == '\r') {
  26                         /* DOS like systems */
  27                         c = fgetc(f);
  28                         if (c != '\n') {
  29                                 ungetc(c, f);
  30                                 c = '\r';
  31                         }
  32                 }
  33                 if (c == '\n')
  34                         config_linenr++;
  35                 if (c == EOF) {
  36                         config_file = NULL;
  37                         c = '\n';
  38                 }
  39         }
  40         return c;
  41 }
  42
  43 static char *parse_value(void)
  44 {
  45         static char value[1024];
  46         int quote = 0, comment = 0, len = 0, space = 0;
  47
  48         for (;;) {
  49                 int c = get_next_char();
  50                 if (len >= sizeof(value))
  51                         return NULL;
  52                 if (c == '\n') {
  53                         if (quote)
  54                                 return NULL;
  55                         value[len] = 0;
  56                         return value;
  57                 }
  58                 if (comment)
  59                         continue;
  60                 if (isspace(c) && !quote) {
  61                         space = 1;
  62                         continue;
  63                 }
  64                 if (!quote) {
  65                         if (c == ';' || c == '#') {
  66                                 comment = 1;
  67                                 continue;
  68                         }
  69                 }
  70                 if (space) {
  71                         if (len)
  72                                 value[len++] = ' ';
  73                         space = 0;
  74                 }
  75                 if (c == '\\') {
  76                         c = get_next_char();
  77                         switch (c) {
  78                         case '\n':
  79                                 continue;
  80                         case 't':
  81                                 c = '\t';
  82                                 break;
  83                         case 'b':
  84                                 c = '\b';
  85                                 break;
  86                         case 'n':
  87                                 c = '\n';
  88                                 break;
  89                         /* Some characters escape as themselves */
  90                         case '\\': case '"':
  91                                 break;
  92                         /* Reject unknown escape sequences */
  93                         default:
  94                                 return NULL;
  95                         }
  96                         value[len++] = c;
  97                         continue;
  98                 }
  99                 if (c == '"') {
 100                         quote = 1-quote;
 101                         continue;
 102                 }
 103                 value[len++] = c;
 104         }
 105 }
 106
 107 static inline int iskeychar(int c)
 108 {
 109         return isalnum(c) || c == '-';
 110 }
 111
 112 static int get_value(config_fn_t fn, char *name, unsigned int len)
 113 {
 114         int c;
 115         char *value;
 116
 117         /* Get the full name */
 118         for (;;) {
 119                 c = get_next_char();
 120                 if (c == EOF)
 121                         break;
 122                 if (!iskeychar(c))
 123                         break;
 124                 name[len++] = tolower(c);
 125                 if (len >= MAXNAME)
 126                         return -1;
 127         }
 128         name[len] = 0;
 129         while (c == ' ' || c == '\t')
 130                 c = get_next_char();
 131
 132         value = NULL;
 133         if (c != '\n') {
 134                 if (c != '=')
 135                         return -1;
 136                 value = parse_value();
 137                 if (!value)
 138                         return -1;
 139         }
 140         return fn(name, value);
 141 }
 142
 143 static int get_extended_base_var(char *name, int baselen, int c)
 144 {
 145         do {
 146                 if (c == '\n')
 147                         return -1;
 148                 c = get_next_char();
 149         } while (isspace(c));
 150
 151         /* We require the format to be '[base "extension"]' */
 152         if (c != '"')
 153                 return -1;
 154         name[baselen++] = '.';
 155
 156         for (;;) {
 157                 int c = get_next_char();
 158                 if (c == '\n')
 159                         return -1;
 160                 if (c == '"')
 161                         break;
 162                 if (c == '\\') {
 163                         c = get_next_char();
 164                         if (c == '\n')
 165                                 return -1;
 166                 }
 167                 name[baselen++] = c;
 168                 if (baselen > MAXNAME / 2)
 169                         return -1;
 170         }
 171
 172         /* Final ']' */
 173         if (get_next_char() != ']')
 174                 return -1;
 175         return baselen;
 176 }
 177
 178 static int get_base_var(char *name)
 179 {
 180         int baselen = 0;
 181
 182         for (;;) {
 183                 int c = get_next_char();
 184                 if (c == EOF)
 185                         return -1;
 186                 if (c == ']')
 187                         return baselen;
 188                 if (isspace(c))
 189                         return get_extended_base_var(name, baselen, c);
 190                 if (!iskeychar(c) && c != '.')
 191                         return -1;
 192                 if (baselen > MAXNAME / 2)
 193                         return -1;
 194                 name[baselen++] = tolower(c);
 195         }
 196 }
 197
 198 static int git_parse_file(config_fn_t fn)
 199 {
 200         int comment = 0;
 201         int baselen = 0;
 202         static char var[MAXNAME];
 203
 204         for (;;) {
 205                 int c = get_next_char();
 206                 if (c == '\n') {
 207                         /* EOF? */
 208                         if (!config_file)
 209                                 return 0;
 210                         comment = 0;
 211                         continue;
 212                 }
 213                 if (comment || isspace(c))
 214                         continue;
 215                 if (c == '#' || c == ';') {
 216                         comment = 1;
 217                         continue;
 218                 }
 219                 if (c == '[') {
 220                         baselen = get_base_var(var);
 221                         if (baselen <= 0)
 222                                 break;
 223                         var[baselen++] = '.';
 224                         var[baselen] = 0;
 225                         continue;
 226                 }
 227                 if (!isalpha(c))
 228                         break;
 229                 var[baselen] = tolower(c);
 230                 if (get_value(fn, var, baselen+1) < 0)
 231                         break;
 232         }
 233         die("bad config file line %d in %s", config_linenr, config_file_name);
 234 }
 235
 236 int git_config_int(const char *name, const char *value)
 237 {
 238         if (value && *value) {
 239                 char *end;
 240                 int val = strtol(value, &end, 0);
 241                 if (!*end)
 242                         return val;
 243                 if (!strcasecmp(end, "k"))
 244                         return val * 1024;
 245                 if (!strcasecmp(end, "m"))
 246                         return val * 1024 * 1024;
 247                 if (!strcasecmp(end, "g"))
 248                         return val * 1024 * 1024 * 1024;
 249         }
 250         die("bad config value for '%s' in %s", name, config_file_name);
 251 }
 252
 253 int git_config_bool(const char *name, const char *value)
 254 {
 255         if (!value)
 256                 return 1;
 257         if (!*value)
 258                 return 0;
 259         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 260                 return 1;
 261         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 262                 return 0;
 263         return git_config_int(name, value) != 0;
 264 }
 265
 266 int git_default_config(const char *var, const char *value)
 267 {
 268         /* This needs a better name */
 269         if (!strcmp(var, "core.filemode")) {
 270                 trust_executable_bit = git_config_bool(var, value);
 271                 return 0;
 272         }
 273
 274         if (!strcmp(var, "core.symlinks")) {
 275                 has_symlinks = git_config_bool(var, value);
 276                 return 0;
 277         }
 278
 279         if (!strcmp(var, "core.bare")) {
 280                 is_bare_repository_cfg = git_config_bool(var, value);
 281                 return 0;
 282         }
 283
 284         if (!strcmp(var, "core.ignorestat")) {
 285                 assume_unchanged = git_config_bool(var, value);
 286                 return 0;
 287         }
 288
 289         if (!strcmp(var, "core.prefersymlinkrefs")) {
 290                 prefer_symlink_refs = git_config_bool(var, value);
 291                 return 0;
 292         }
 293
 294         if (!strcmp(var, "core.logallrefupdates")) {
 295                 log_all_ref_updates = git_config_bool(var, value);
 296                 return 0;
 297         }
 298
 299         if (!strcmp(var, "core.warnambiguousrefs")) {
 300                 warn_ambiguous_refs = git_config_bool(var, value);
 301                 return 0;
 302         }
 303
 304         if (!strcmp(var, "core.loosecompression")) {
 305                 int level = git_config_int(var, value);
 306                 if (level == -1)
 307                         level = Z_DEFAULT_COMPRESSION;
 308                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 309                         die("bad zlib compression level %d", level);
 310                 zlib_compression_level = level;
 311                 zlib_compression_seen = 1;
 312                 return 0;
 313         }
 314
 315         if (!strcmp(var, "core.compression")) {
 316                 int level = git_config_int(var, value);
 317                 if (level == -1)
 318                         level = Z_DEFAULT_COMPRESSION;
 319                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 320                         die("bad zlib compression level %d", level);
 321                 core_compression_level = level;
 322                 core_compression_seen = 1;
 323                 if (!zlib_compression_seen)
 324                         zlib_compression_level = level;
 325                 return 0;
 326         }
 327
 328         if (!strcmp(var, "core.packedgitwindowsize")) {
 329                 int pgsz_x2 = getpagesize() * 2;
 330                 packed_git_window_size = git_config_int(var, value);
 331
 332                 /* This value must be multiple of (pagesize * 2) */
 333                 packed_git_window_size /= pgsz_x2;
 334                 if (packed_git_window_size < 1)
 335                         packed_git_window_size = 1;
 336                 packed_git_window_size *= pgsz_x2;
 337                 return 0;
 338         }
 339
 340         if (!strcmp(var, "core.packedgitlimit")) {
 341                 packed_git_limit = git_config_int(var, value);
 342                 return 0;
 343         }
 344
 345         if (!strcmp(var, "core.deltabasecachelimit")) {
 346                 delta_base_cache_limit = git_config_int(var, value);
 347                 return 0;
 348         }
 349
 350         if (!strcmp(var, "core.autocrlf")) {
 351                 if (value && !strcasecmp(value, "input")) {
 352                         auto_crlf = -1;
 353                         return 0;
 354                 }
 355                 auto_crlf = git_config_bool(var, value);
 356                 return 0;
 357         }
 358
 359         if (!strcmp(var, "user.name")) {
 360                 strlcpy(git_default_name, value, sizeof(git_default_name));
 361                 return 0;
 362         }
 363
 364         if (!strcmp(var, "user.email")) {
 365                 strlcpy(git_default_email, value, sizeof(git_default_email));
 366                 return 0;
 367         }
 368
 369         if (!strcmp(var, "i18n.commitencoding")) {
 370                 git_commit_encoding = xstrdup(value);
 371                 return 0;
 372         }
 373
 374         if (!strcmp(var, "i18n.logoutputencoding")) {
 375                 git_log_output_encoding = xstrdup(value);
 376                 return 0;
 377         }
 378
 379
 380         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 381                 pager_use_color = git_config_bool(var,value);
 382                 return 0;
 383         }
 384
 385         /* Add other config variables here and to Documentation/config.txt. */
 386         return 0;
 387 }
 388
 389 int git_config_from_file(config_fn_t fn, const char *filename)
 390 {
 391         int ret;
 392         FILE *f = fopen(filename, "r");
 393
 394         ret = -1;
 395         if (f) {
 396                 config_file = f;
 397                 config_file_name = filename;
 398                 config_linenr = 1;
 399                 ret = git_parse_file(fn);
 400                 fclose(f);
 401                 config_file_name = NULL;
 402         }
 403         return ret;
 404 }
 405
 406 int git_config(config_fn_t fn)
 407 {
 408         int ret = 0;
 409         char *repo_config = NULL;
 410         const char *home = NULL, *filename;
 411
 412         /* $GIT_CONFIG makes git read _only_ the given config file,
 413          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 414          * global config file, the same way it would the per-repository
 415          * config file otherwise. */
 416         filename = getenv(CONFIG_ENVIRONMENT);
 417         if (!filename) {
 418                 if (!access(ETC_GITCONFIG, R_OK))
 419                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 420                 home = getenv("HOME");
 421                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 422                 if (!filename)
 423                         filename = repo_config = xstrdup(git_path("config"));
 424         }
 425
 426         if (home) {
 427                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 428                 if (!access(user_config, R_OK))
 429                         ret = git_config_from_file(fn, user_config);
 430                 free(user_config);
 431         }
 432
 433         ret += git_config_from_file(fn, filename);
 434         free(repo_config);
 435         return ret;
 436 }
 437
 438 /*
 439  * Find all the stuff for git_config_set() below.
 440  */
 441
 442 #define MAX_MATCHES 512
 443
 444 static struct {
 445         int baselen;
 446         char* key;
 447         int do_not_match;
 448         regex_t* value_regex;
 449         int multi_replace;
 450         size_t offset[MAX_MATCHES];
 451         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 452         int seen;
 453 } store;
 454
 455 static int matches(const char* key, const char* value)
 456 {
 457         return !strcmp(key, store.key) &&
 458                 (store.value_regex == NULL ||
 459                  (store.do_not_match ^
 460                   !regexec(store.value_regex, value, 0, NULL, 0)));
 461 }
 462
 463 static int store_aux(const char* key, const char* value)
 464 {
 465         const char *ep;
 466         size_t section_len;
 467
 468         switch (store.state) {
 469         case KEY_SEEN:
 470                 if (matches(key, value)) {
 471                         if (store.seen == 1 && store.multi_replace == 0) {
 472                                 fprintf(stderr,
 473                                         "Warning: %s has multiple values\n",
 474                                         key);
 475                         } else if (store.seen >= MAX_MATCHES) {
 476                                 fprintf(stderr, "Too many matches\n");
 477                                 return 1;
 478                         }
 479
 480                         store.offset[store.seen] = ftell(config_file);
 481                         store.seen++;
 482                 }
 483                 break;
 484         case SECTION_SEEN:
 485                 /*
 486                  * What we are looking for is in store.key (both
 487                  * section and var), and its section part is baselen
 488                  * long.  We found key (again, both section and var).
 489                  * We would want to know if this key is in the same
 490                  * section as what we are looking for.  We already
 491                  * know we are in the same section as what should
 492                  * hold store.key.
 493                  */
 494                 ep = strrchr(key, '.');
 495                 section_len = ep - key;
 496
 497                 if ((section_len != store.baselen) ||
 498                     memcmp(key, store.key, section_len+1)) {
 499                         store.state = SECTION_END_SEEN;
 500                         break;
 501                 }
 502
 503                 /*
 504                  * Do not increment matches: this is no match, but we
 505                  * just made sure we are in the desired section.
 506                  */
 507                 store.offset[store.seen] = ftell(config_file);
 508                 /* fallthru */
 509         case SECTION_END_SEEN:
 510         case START:
 511                 if (matches(key, value)) {
 512                         store.offset[store.seen] = ftell(config_file);
 513                         store.state = KEY_SEEN;
 514                         store.seen++;
 515                 } else {
 516                         if (strrchr(key, '.') - key == store.baselen &&
 517                               !strncmp(key, store.key, store.baselen)) {
 518                                         store.state = SECTION_SEEN;
 519                                         store.offset[store.seen] = ftell(config_file);
 520                         }
 521                 }
 522         }
 523         return 0;
 524 }
 525
 526 static int write_error()
 527 {
 528         fprintf(stderr, "Failed to write new configuration file\n");
 529
 530         /* Same error code as "failed to rename". */
 531         return 4;
 532 }
 533
 534 static int store_write_section(int fd, const char* key)
 535 {
 536         const char *dot = strchr(key, '.');
 537         int len1 = store.baselen, len2 = -1;
 538
 539         dot = strchr(key, '.');
 540         if (dot) {
 541                 int dotlen = dot - key;
 542                 if (dotlen < len1) {
 543                         len2 = len1 - dotlen - 1;
 544                         len1 = dotlen;
 545                 }
 546         }
 547
 548         if (write_in_full(fd, "[", 1) != 1 ||
 549             write_in_full(fd, key, len1) != len1)
 550                 return 0;
 551         if (len2 >= 0) {
 552                 if (write_in_full(fd, " \"", 2) != 2)
 553                         return 0;
 554                 while (--len2 >= 0) {
 555                         unsigned char c = *++dot;
 556                         if (c == '"')
 557                                 if (write_in_full(fd, "\\", 1) != 1)
 558                                         return 0;
 559                         if (write_in_full(fd, &c, 1) != 1)
 560                                 return 0;
 561                 }
 562                 if (write_in_full(fd, "\"", 1) != 1)
 563                         return 0;
 564         }
 565         if (write_in_full(fd, "]\n", 2) != 2)
 566                 return 0;
 567
 568         return 1;
 569 }
 570
 571 static int store_write_pair(int fd, const char* key, const char* value)
 572 {
 573         int i;
 574         int length = strlen(key+store.baselen+1);
 575         int quote = 0;
 576
 577         /* Check to see if the value needs to be quoted. */
 578         if (value[0] == ' ')
 579                 quote = 1;
 580         for (i = 0; value[i]; i++)
 581                 if (value[i] == ';' || value[i] == '#')
 582                         quote = 1;
 583         if (value[i-1] == ' ')
 584                 quote = 1;
 585
 586         if (write_in_full(fd, "\t", 1) != 1 ||
 587             write_in_full(fd, key+store.baselen+1, length) != length ||
 588             write_in_full(fd, " = ", 3) != 3)
 589                 return 0;
 590         if (quote && write_in_full(fd, "\"", 1) != 1)
 591                 return 0;
 592         for (i = 0; value[i]; i++)
 593                 switch (value[i]) {
 594                 case '\n':
 595                         if (write_in_full(fd, "\\n", 2) != 2)
 596                                 return 0;
 597                         break;
 598                 case '\t':
 599                         if (write_in_full(fd, "\\t", 2) != 2)
 600                                 return 0;
 601                         break;
 602                 case '"':
 603                 case '\\':
 604                         if (write_in_full(fd, "\\", 1) != 1)
 605                                 return 0;
 606                 default:
 607                         if (write_in_full(fd, value+i, 1) != 1)
 608                                 return 0;
 609                         break;
 610                 }
 611         if (quote && write_in_full(fd, "\"", 1) != 1)
 612                 return 0;
 613         if (write_in_full(fd, "\n", 1) != 1)
 614                 return 0;
 615         return 1;
 616 }
 617
 618 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 619         size_t offset_, int* found_bracket)
 620 {
 621         size_t equal_offset = size, bracket_offset = size;
 622         ssize_t offset;
 623
 624         for (offset = offset_-2; offset > 0
 625                         && contents[offset] != '\n'; offset--)
 626                 switch (contents[offset]) {
 627                         case '=': equal_offset = offset; break;
 628                         case ']': bracket_offset = offset; break;
 629                 }
 630         if (bracket_offset < equal_offset) {
 631                 *found_bracket = 1;
 632                 offset = bracket_offset+1;
 633         } else
 634                 offset++;
 635
 636         return offset;
 637 }
 638
 639 int git_config_set(const char* key, const char* value)
 640 {
 641         return git_config_set_multivar(key, value, NULL, 0);
 642 }
 643
 644 /*
 645  * If value==NULL, unset in (remove from) config,
 646  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 647  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 648  *     else all matching key/values (regardless how many) are removed,
 649  *     before the new pair is written.
 650  *
 651  * Returns 0 on success.
 652  *
 653  * This function does this:
 654  *
 655  * - it locks the config file by creating ".git/config.lock"
 656  *
 657  * - it then parses the config using store_aux() as validator to find
 658  *   the position on the key/value pair to replace. If it is to be unset,
 659  *   it must be found exactly once.
 660  *
 661  * - the config file is mmap()ed and the part before the match (if any) is
 662  *   written to the lock file, then the changed part and the rest.
 663  *
 664  * - the config file is removed and the lock file rename()d to it.
 665  *
 666  */
 667 int git_config_set_multivar(const char* key, const char* value,
 668         const char* value_regex, int multi_replace)
 669 {
 670         int i, dot;
 671         int fd = -1, in_fd;
 672         int ret;
 673         char* config_filename;
 674         char* lock_file;
 675         const char* last_dot = strrchr(key, '.');
 676
 677         config_filename = getenv(CONFIG_ENVIRONMENT);
 678         if (!config_filename) {
 679                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 680                 if (!config_filename)
 681                         config_filename  = git_path("config");
 682         }
 683         config_filename = xstrdup(config_filename);
 684         lock_file = xstrdup(mkpath("%s.lock", config_filename));
 685
 686         /*
 687          * Since "key" actually contains the section name and the real
 688          * key name separated by a dot, we have to know where the dot is.
 689          */
 690
 691         if (last_dot == NULL) {
 692                 fprintf(stderr, "key does not contain a section: %s\n", key);
 693                 ret = 2;
 694                 goto out_free;
 695         }
 696         store.baselen = last_dot - key;
 697
 698         store.multi_replace = multi_replace;
 699
 700         /*
 701          * Validate the key and while at it, lower case it for matching.
 702          */
 703         store.key = xmalloc(strlen(key) + 1);
 704         dot = 0;
 705         for (i = 0; key[i]; i++) {
 706                 unsigned char c = key[i];
 707                 if (c == '.')
 708                         dot = 1;
 709                 /* Leave the extended basename untouched.. */
 710                 if (!dot || i > store.baselen) {
 711                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 712                                 fprintf(stderr, "invalid key: %s\n", key);
 713                                 free(store.key);
 714                                 ret = 1;
 715                                 goto out_free;
 716                         }
 717                         c = tolower(c);
 718                 } else if (c == '\n') {
 719                         fprintf(stderr, "invalid key (newline): %s\n", key);
 720                         free(store.key);
 721                         ret = 1;
 722                         goto out_free;
 723                 }
 724                 store.key[i] = c;
 725         }
 726         store.key[i] = 0;
 727
 728         /*
 729          * The lock_file serves a purpose in addition to locking: the new
 730          * contents of .git/config will be written into it.
 731          */
 732         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 733         if (fd < 0 || adjust_shared_perm(lock_file)) {
 734                 fprintf(stderr, "could not lock config file\n");
 735                 free(store.key);
 736                 ret = -1;
 737                 goto out_free;
 738         }
 739
 740         /*
 741          * If .git/config does not exist yet, write a minimal version.
 742          */
 743         in_fd = open(config_filename, O_RDONLY);
 744         if ( in_fd < 0 ) {
 745                 free(store.key);
 746
 747                 if ( ENOENT != errno ) {
 748                         error("opening %s: %s", config_filename,
 749                               strerror(errno));
 750                         ret = 3; /* same as "invalid config file" */
 751                         goto out_free;
 752                 }
 753                 /* if nothing to unset, error out */
 754                 if (value == NULL) {
 755                         ret = 5;
 756                         goto out_free;
 757                 }
 758
 759                 store.key = (char*)key;
 760                 if (!store_write_section(fd, key) ||
 761                     !store_write_pair(fd, key, value))
 762                         goto write_err_out;
 763         } else {
 764                 struct stat st;
 765                 char* contents;
 766                 size_t contents_sz, copy_begin, copy_end;
 767                 int i, new_line = 0;
 768
 769                 if (value_regex == NULL)
 770                         store.value_regex = NULL;
 771                 else {
 772                         if (value_regex[0] == '!') {
 773                                 store.do_not_match = 1;
 774                                 value_regex++;
 775                         } else
 776                                 store.do_not_match = 0;
 777
 778                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 779                         if (regcomp(store.value_regex, value_regex,
 780                                         REG_EXTENDED)) {
 781                                 fprintf(stderr, "Invalid pattern: %s\n",
 782                                         value_regex);
 783                                 free(store.value_regex);
 784                                 ret = 6;
 785                                 goto out_free;
 786                         }
 787                 }
 788
 789                 store.offset[0] = 0;
 790                 store.state = START;
 791                 store.seen = 0;
 792
 793                 /*
 794                  * After this, store.offset will contain the *end* offset
 795                  * of the last match, or remain at 0 if no match was found.
 796                  * As a side effect, we make sure to transform only a valid
 797                  * existing config file.
 798                  */
 799                 if (git_config_from_file(store_aux, config_filename)) {
 800                         fprintf(stderr, "invalid config file\n");
 801                         free(store.key);
 802                         if (store.value_regex != NULL) {
 803                                 regfree(store.value_regex);
 804                                 free(store.value_regex);
 805                         }
 806                         ret = 3;
 807                         goto out_free;
 808                 }
 809
 810                 free(store.key);
 811                 if (store.value_regex != NULL) {
 812                         regfree(store.value_regex);
 813                         free(store.value_regex);
 814                 }
 815
 816                 /* if nothing to unset, or too many matches, error out */
 817                 if ((store.seen == 0 && value == NULL) ||
 818                                 (store.seen > 1 && multi_replace == 0)) {
 819                         ret = 5;
 820                         goto out_free;
 821                 }
 822
 823                 fstat(in_fd, &st);
 824                 contents_sz = xsize_t(st.st_size);
 825                 contents = xmmap(NULL, contents_sz, PROT_READ,
 826                         MAP_PRIVATE, in_fd, 0);
 827                 close(in_fd);
 828
 829                 if (store.seen == 0)
 830                         store.seen = 1;
 831
 832                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 833                         if (store.offset[i] == 0) {
 834                                 store.offset[i] = copy_end = contents_sz;
 835                         } else if (store.state != KEY_SEEN) {
 836                                 copy_end = store.offset[i];
 837                         } else
 838                                 copy_end = find_beginning_of_line(
 839                                         contents, contents_sz,
 840                                         store.offset[i]-2, &new_line);
 841
 842                         /* write the first part of the config */
 843                         if (copy_end > copy_begin) {
 844                                 if (write_in_full(fd, contents + copy_begin,
 845                                                   copy_end - copy_begin) <
 846                                     copy_end - copy_begin)
 847                                         goto write_err_out;
 848                                 if (new_line &&
 849                                     write_in_full(fd, "\n", 1) != 1)
 850                                         goto write_err_out;
 851                         }
 852                         copy_begin = store.offset[i];
 853                 }
 854
 855                 /* write the pair (value == NULL means unset) */
 856                 if (value != NULL) {
 857                         if (store.state == START) {
 858                                 if (!store_write_section(fd, key))
 859                                         goto write_err_out;
 860                         }
 861                         if (!store_write_pair(fd, key, value))
 862                                 goto write_err_out;
 863                 }
 864
 865                 /* write the rest of the config */
 866                 if (copy_begin < contents_sz)
 867                         if (write_in_full(fd, contents + copy_begin,
 868                                           contents_sz - copy_begin) <
 869                             contents_sz - copy_begin)
 870                                 goto write_err_out;
 871
 872                 munmap(contents, contents_sz);
 873                 unlink(config_filename);
 874         }
 875
 876         if (rename(lock_file, config_filename) < 0) {
 877                 fprintf(stderr, "Could not rename the lock file?\n");
 878                 ret = 4;
 879                 goto out_free;
 880         }
 881
 882         ret = 0;
 883
 884 out_free:
 885         if (0 <= fd)
 886                 close(fd);
 887         free(config_filename);
 888         if (lock_file) {
 889                 unlink(lock_file);
 890                 free(lock_file);
 891         }
 892         return ret;
 893
 894 write_err_out:
 895         ret = write_error();
 896         goto out_free;
 897
 898 }
 899
 900 static int section_name_match (const char *buf, const char *name)
 901 {
 902         int i = 0, j = 0, dot = 0;
 903         for (; buf[i] && buf[i] != ']'; i++) {
 904                 if (!dot && isspace(buf[i])) {
 905                         dot = 1;
 906                         if (name[j++] != '.')
 907                                 break;
 908                         for (i++; isspace(buf[i]); i++)
 909                                 ; /* do nothing */
 910                         if (buf[i] != '"')
 911                                 break;
 912                         continue;
 913                 }
 914                 if (buf[i] == '\\' && dot)
 915                         i++;
 916                 else if (buf[i] == '"' && dot) {
 917                         for (i++; isspace(buf[i]); i++)
 918                                 ; /* do_nothing */
 919                         break;
 920                 }
 921                 if (buf[i] != name[j++])
 922                         break;
 923         }
 924         return (buf[i] == ']' && name[j] == 0);
 925 }
 926
 927 /* if new_name == NULL, the section is removed instead */
 928 int git_config_rename_section(const char *old_name, const char *new_name)
 929 {
 930         int ret = 0, remove = 0;
 931         char *config_filename;
 932         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 933         int out_fd;
 934         char buf[1024];
 935
 936         config_filename = getenv(CONFIG_ENVIRONMENT);
 937         if (!config_filename) {
 938                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 939                 if (!config_filename)
 940                         config_filename  = git_path("config");
 941         }
 942         config_filename = xstrdup(config_filename);
 943         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 944         if (out_fd < 0) {
 945                 ret = error("Could not lock config file!");
 946                 goto out;
 947         }
 948
 949         if (!(config_file = fopen(config_filename, "rb"))) {
 950                 /* no config file means nothing to rename, no error */
 951                 goto unlock_and_out;
 952         }
 953
 954         while (fgets(buf, sizeof(buf), config_file)) {
 955                 int i;
 956                 int length;
 957                 for (i = 0; buf[i] && isspace(buf[i]); i++)
 958                         ; /* do nothing */
 959                 if (buf[i] == '[') {
 960                         /* it's a section */
 961                         if (section_name_match (&buf[i+1], old_name)) {
 962                                 ret++;
 963                                 if (new_name == NULL) {
 964                                         remove = 1;
 965                                         continue;
 966                                 }
 967                                 store.baselen = strlen(new_name);
 968                                 if (!store_write_section(out_fd, new_name)) {
 969                                         ret = write_error();
 970                                         goto out;
 971                                 }
 972                                 continue;
 973                         }
 974                         remove = 0;
 975                 }
 976                 if (remove)
 977                         continue;
 978                 length = strlen(buf);
 979                 if (write_in_full(out_fd, buf, length) != length) {
 980                         ret = write_error();
 981                         goto out;
 982                 }
 983         }
 984         fclose(config_file);
 985  unlock_and_out:
 986         if (close(out_fd) || commit_lock_file(lock) < 0)
 987                         ret = error("Cannot commit config file!");
 988  out:
 989         free(config_filename);
 990         return ret;
 991 }