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.quotepath")) {
 275                 quote_path_fully = git_config_bool(var, value);
 276                 return 0;
 277         }
 278
 279         if (!strcmp(var, "core.symlinks")) {
 280                 has_symlinks = git_config_bool(var, value);
 281                 return 0;
 282         }
 283
 284         if (!strcmp(var, "core.bare")) {
 285                 is_bare_repository_cfg = git_config_bool(var, value);
 286                 return 0;
 287         }
 288
 289         if (!strcmp(var, "core.ignorestat")) {
 290                 assume_unchanged = git_config_bool(var, value);
 291                 return 0;
 292         }
 293
 294         if (!strcmp(var, "core.prefersymlinkrefs")) {
 295                 prefer_symlink_refs = git_config_bool(var, value);
 296                 return 0;
 297         }
 298
 299         if (!strcmp(var, "core.logallrefupdates")) {
 300                 log_all_ref_updates = git_config_bool(var, value);
 301                 return 0;
 302         }
 303
 304         if (!strcmp(var, "core.warnambiguousrefs")) {
 305                 warn_ambiguous_refs = git_config_bool(var, value);
 306                 return 0;
 307         }
 308
 309         if (!strcmp(var, "core.loosecompression")) {
 310                 int level = git_config_int(var, value);
 311                 if (level == -1)
 312                         level = Z_DEFAULT_COMPRESSION;
 313                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 314                         die("bad zlib compression level %d", level);
 315                 zlib_compression_level = level;
 316                 zlib_compression_seen = 1;
 317                 return 0;
 318         }
 319
 320         if (!strcmp(var, "core.compression")) {
 321                 int level = git_config_int(var, value);
 322                 if (level == -1)
 323                         level = Z_DEFAULT_COMPRESSION;
 324                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 325                         die("bad zlib compression level %d", level);
 326                 core_compression_level = level;
 327                 core_compression_seen = 1;
 328                 if (!zlib_compression_seen)
 329                         zlib_compression_level = level;
 330                 return 0;
 331         }
 332
 333         if (!strcmp(var, "core.packedgitwindowsize")) {
 334                 int pgsz_x2 = getpagesize() * 2;
 335                 packed_git_window_size = git_config_int(var, value);
 336
 337                 /* This value must be multiple of (pagesize * 2) */
 338                 packed_git_window_size /= pgsz_x2;
 339                 if (packed_git_window_size < 1)
 340                         packed_git_window_size = 1;
 341                 packed_git_window_size *= pgsz_x2;
 342                 return 0;
 343         }
 344
 345         if (!strcmp(var, "core.packedgitlimit")) {
 346                 packed_git_limit = git_config_int(var, value);
 347                 return 0;
 348         }
 349
 350         if (!strcmp(var, "core.deltabasecachelimit")) {
 351                 delta_base_cache_limit = git_config_int(var, value);
 352                 return 0;
 353         }
 354
 355         if (!strcmp(var, "core.autocrlf")) {
 356                 if (value && !strcasecmp(value, "input")) {
 357                         auto_crlf = -1;
 358                         return 0;
 359                 }
 360                 auto_crlf = git_config_bool(var, value);
 361                 return 0;
 362         }
 363
 364         if (!strcmp(var, "user.name")) {
 365                 strlcpy(git_default_name, value, sizeof(git_default_name));
 366                 return 0;
 367         }
 368
 369         if (!strcmp(var, "user.email")) {
 370                 strlcpy(git_default_email, value, sizeof(git_default_email));
 371                 return 0;
 372         }
 373
 374         if (!strcmp(var, "i18n.commitencoding")) {
 375                 git_commit_encoding = xstrdup(value);
 376                 return 0;
 377         }
 378
 379         if (!strcmp(var, "i18n.logoutputencoding")) {
 380                 git_log_output_encoding = xstrdup(value);
 381                 return 0;
 382         }
 383
 384
 385         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 386                 pager_use_color = git_config_bool(var,value);
 387                 return 0;
 388         }
 389
 390         /* Add other config variables here and to Documentation/config.txt. */
 391         return 0;
 392 }
 393
 394 int git_config_from_file(config_fn_t fn, const char *filename)
 395 {
 396         int ret;
 397         FILE *f = fopen(filename, "r");
 398
 399         ret = -1;
 400         if (f) {
 401                 config_file = f;
 402                 config_file_name = filename;
 403                 config_linenr = 1;
 404                 ret = git_parse_file(fn);
 405                 fclose(f);
 406                 config_file_name = NULL;
 407         }
 408         return ret;
 409 }
 410
 411 int git_config(config_fn_t fn)
 412 {
 413         int ret = 0;
 414         char *repo_config = NULL;
 415         const char *home = NULL, *filename;
 416
 417         /* $GIT_CONFIG makes git read _only_ the given config file,
 418          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 419          * global config file, the same way it would the per-repository
 420          * config file otherwise. */
 421         filename = getenv(CONFIG_ENVIRONMENT);
 422         if (!filename) {
 423                 if (!access(ETC_GITCONFIG, R_OK))
 424                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 425                 home = getenv("HOME");
 426                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 427                 if (!filename)
 428                         filename = repo_config = xstrdup(git_path("config"));
 429         }
 430
 431         if (home) {
 432                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 433                 if (!access(user_config, R_OK))
 434                         ret = git_config_from_file(fn, user_config);
 435                 free(user_config);
 436         }
 437
 438         ret += git_config_from_file(fn, filename);
 439         free(repo_config);
 440         return ret;
 441 }
 442
 443 /*
 444  * Find all the stuff for git_config_set() below.
 445  */
 446
 447 #define MAX_MATCHES 512
 448
 449 static struct {
 450         int baselen;
 451         char* key;
 452         int do_not_match;
 453         regex_t* value_regex;
 454         int multi_replace;
 455         size_t offset[MAX_MATCHES];
 456         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 457         int seen;
 458 } store;
 459
 460 static int matches(const char* key, const char* value)
 461 {
 462         return !strcmp(key, store.key) &&
 463                 (store.value_regex == NULL ||
 464                  (store.do_not_match ^
 465                   !regexec(store.value_regex, value, 0, NULL, 0)));
 466 }
 467
 468 static int store_aux(const char* key, const char* value)
 469 {
 470         const char *ep;
 471         size_t section_len;
 472
 473         switch (store.state) {
 474         case KEY_SEEN:
 475                 if (matches(key, value)) {
 476                         if (store.seen == 1 && store.multi_replace == 0) {
 477                                 fprintf(stderr,
 478                                         "Warning: %s has multiple values\n",
 479                                         key);
 480                         } else if (store.seen >= MAX_MATCHES) {
 481                                 fprintf(stderr, "Too many matches\n");
 482                                 return 1;
 483                         }
 484
 485                         store.offset[store.seen] = ftell(config_file);
 486                         store.seen++;
 487                 }
 488                 break;
 489         case SECTION_SEEN:
 490                 /*
 491                  * What we are looking for is in store.key (both
 492                  * section and var), and its section part is baselen
 493                  * long.  We found key (again, both section and var).
 494                  * We would want to know if this key is in the same
 495                  * section as what we are looking for.  We already
 496                  * know we are in the same section as what should
 497                  * hold store.key.
 498                  */
 499                 ep = strrchr(key, '.');
 500                 section_len = ep - key;
 501
 502                 if ((section_len != store.baselen) ||
 503                     memcmp(key, store.key, section_len+1)) {
 504                         store.state = SECTION_END_SEEN;
 505                         break;
 506                 }
 507
 508                 /*
 509                  * Do not increment matches: this is no match, but we
 510                  * just made sure we are in the desired section.
 511                  */
 512                 store.offset[store.seen] = ftell(config_file);
 513                 /* fallthru */
 514         case SECTION_END_SEEN:
 515         case START:
 516                 if (matches(key, value)) {
 517                         store.offset[store.seen] = ftell(config_file);
 518                         store.state = KEY_SEEN;
 519                         store.seen++;
 520                 } else {
 521                         if (strrchr(key, '.') - key == store.baselen &&
 522                               !strncmp(key, store.key, store.baselen)) {
 523                                         store.state = SECTION_SEEN;
 524                                         store.offset[store.seen] = ftell(config_file);
 525                         }
 526                 }
 527         }
 528         return 0;
 529 }
 530
 531 static int write_error(void)
 532 {
 533         fprintf(stderr, "Failed to write new configuration file\n");
 534
 535         /* Same error code as "failed to rename". */
 536         return 4;
 537 }
 538
 539 static int store_write_section(int fd, const char* key)
 540 {
 541         const char *dot = strchr(key, '.');
 542         int len1 = store.baselen, len2 = -1;
 543
 544         dot = strchr(key, '.');
 545         if (dot) {
 546                 int dotlen = dot - key;
 547                 if (dotlen < len1) {
 548                         len2 = len1 - dotlen - 1;
 549                         len1 = dotlen;
 550                 }
 551         }
 552
 553         if (write_in_full(fd, "[", 1) != 1 ||
 554             write_in_full(fd, key, len1) != len1)
 555                 return 0;
 556         if (len2 >= 0) {
 557                 if (write_in_full(fd, " \"", 2) != 2)
 558                         return 0;
 559                 while (--len2 >= 0) {
 560                         unsigned char c = *++dot;
 561                         if (c == '"')
 562                                 if (write_in_full(fd, "\\", 1) != 1)
 563                                         return 0;
 564                         if (write_in_full(fd, &c, 1) != 1)
 565                                 return 0;
 566                 }
 567                 if (write_in_full(fd, "\"", 1) != 1)
 568                         return 0;
 569         }
 570         if (write_in_full(fd, "]\n", 2) != 2)
 571                 return 0;
 572
 573         return 1;
 574 }
 575
 576 static int store_write_pair(int fd, const char* key, const char* value)
 577 {
 578         int i;
 579         int length = strlen(key+store.baselen+1);
 580         int quote = 0;
 581
 582         /* Check to see if the value needs to be quoted. */
 583         if (value[0] == ' ')
 584                 quote = 1;
 585         for (i = 0; value[i]; i++)
 586                 if (value[i] == ';' || value[i] == '#')
 587                         quote = 1;
 588         if (value[i-1] == ' ')
 589                 quote = 1;
 590
 591         if (write_in_full(fd, "\t", 1) != 1 ||
 592             write_in_full(fd, key+store.baselen+1, length) != length ||
 593             write_in_full(fd, " = ", 3) != 3)
 594                 return 0;
 595         if (quote && write_in_full(fd, "\"", 1) != 1)
 596                 return 0;
 597         for (i = 0; value[i]; i++)
 598                 switch (value[i]) {
 599                 case '\n':
 600                         if (write_in_full(fd, "\\n", 2) != 2)
 601                                 return 0;
 602                         break;
 603                 case '\t':
 604                         if (write_in_full(fd, "\\t", 2) != 2)
 605                                 return 0;
 606                         break;
 607                 case '"':
 608                 case '\\':
 609                         if (write_in_full(fd, "\\", 1) != 1)
 610                                 return 0;
 611                 default:
 612                         if (write_in_full(fd, value+i, 1) != 1)
 613                                 return 0;
 614                         break;
 615                 }
 616         if (quote && write_in_full(fd, "\"", 1) != 1)
 617                 return 0;
 618         if (write_in_full(fd, "\n", 1) != 1)
 619                 return 0;
 620         return 1;
 621 }
 622
 623 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 624         size_t offset_, int* found_bracket)
 625 {
 626         size_t equal_offset = size, bracket_offset = size;
 627         ssize_t offset;
 628
 629         for (offset = offset_-2; offset > 0
 630                         && contents[offset] != '\n'; offset--)
 631                 switch (contents[offset]) {
 632                         case '=': equal_offset = offset; break;
 633                         case ']': bracket_offset = offset; break;
 634                 }
 635         if (bracket_offset < equal_offset) {
 636                 *found_bracket = 1;
 637                 offset = bracket_offset+1;
 638         } else
 639                 offset++;
 640
 641         return offset;
 642 }
 643
 644 int git_config_set(const char* key, const char* value)
 645 {
 646         return git_config_set_multivar(key, value, NULL, 0);
 647 }
 648
 649 /*
 650  * If value==NULL, unset in (remove from) config,
 651  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 652  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 653  *     else all matching key/values (regardless how many) are removed,
 654  *     before the new pair is written.
 655  *
 656  * Returns 0 on success.
 657  *
 658  * This function does this:
 659  *
 660  * - it locks the config file by creating ".git/config.lock"
 661  *
 662  * - it then parses the config using store_aux() as validator to find
 663  *   the position on the key/value pair to replace. If it is to be unset,
 664  *   it must be found exactly once.
 665  *
 666  * - the config file is mmap()ed and the part before the match (if any) is
 667  *   written to the lock file, then the changed part and the rest.
 668  *
 669  * - the config file is removed and the lock file rename()d to it.
 670  *
 671  */
 672 int git_config_set_multivar(const char* key, const char* value,
 673         const char* value_regex, int multi_replace)
 674 {
 675         int i, dot;
 676         int fd = -1, in_fd;
 677         int ret;
 678         char* config_filename;
 679         char* lock_file;
 680         const char* last_dot = strrchr(key, '.');
 681
 682         config_filename = getenv(CONFIG_ENVIRONMENT);
 683         if (!config_filename) {
 684                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 685                 if (!config_filename)
 686                         config_filename  = git_path("config");
 687         }
 688         config_filename = xstrdup(config_filename);
 689         lock_file = xstrdup(mkpath("%s.lock", config_filename));
 690
 691         /*
 692          * Since "key" actually contains the section name and the real
 693          * key name separated by a dot, we have to know where the dot is.
 694          */
 695
 696         if (last_dot == NULL) {
 697                 fprintf(stderr, "key does not contain a section: %s\n", key);
 698                 ret = 2;
 699                 goto out_free;
 700         }
 701         store.baselen = last_dot - key;
 702
 703         store.multi_replace = multi_replace;
 704
 705         /*
 706          * Validate the key and while at it, lower case it for matching.
 707          */
 708         store.key = xmalloc(strlen(key) + 1);
 709         dot = 0;
 710         for (i = 0; key[i]; i++) {
 711                 unsigned char c = key[i];
 712                 if (c == '.')
 713                         dot = 1;
 714                 /* Leave the extended basename untouched.. */
 715                 if (!dot || i > store.baselen) {
 716                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 717                                 fprintf(stderr, "invalid key: %s\n", key);
 718                                 free(store.key);
 719                                 ret = 1;
 720                                 goto out_free;
 721                         }
 722                         c = tolower(c);
 723                 } else if (c == '\n') {
 724                         fprintf(stderr, "invalid key (newline): %s\n", key);
 725                         free(store.key);
 726                         ret = 1;
 727                         goto out_free;
 728                 }
 729                 store.key[i] = c;
 730         }
 731         store.key[i] = 0;
 732
 733         /*
 734          * The lock_file serves a purpose in addition to locking: the new
 735          * contents of .git/config will be written into it.
 736          */
 737         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 738         if (fd < 0 || adjust_shared_perm(lock_file)) {
 739                 fprintf(stderr, "could not lock config file\n");
 740                 free(store.key);
 741                 ret = -1;
 742                 goto out_free;
 743         }
 744
 745         /*
 746          * If .git/config does not exist yet, write a minimal version.
 747          */
 748         in_fd = open(config_filename, O_RDONLY);
 749         if ( in_fd < 0 ) {
 750                 free(store.key);
 751
 752                 if ( ENOENT != errno ) {
 753                         error("opening %s: %s", config_filename,
 754                               strerror(errno));
 755                         ret = 3; /* same as "invalid config file" */
 756                         goto out_free;
 757                 }
 758                 /* if nothing to unset, error out */
 759                 if (value == NULL) {
 760                         ret = 5;
 761                         goto out_free;
 762                 }
 763
 764                 store.key = (char*)key;
 765                 if (!store_write_section(fd, key) ||
 766                     !store_write_pair(fd, key, value))
 767                         goto write_err_out;
 768         } else {
 769                 struct stat st;
 770                 char* contents;
 771                 size_t contents_sz, copy_begin, copy_end;
 772                 int i, new_line = 0;
 773
 774                 if (value_regex == NULL)
 775                         store.value_regex = NULL;
 776                 else {
 777                         if (value_regex[0] == '!') {
 778                                 store.do_not_match = 1;
 779                                 value_regex++;
 780                         } else
 781                                 store.do_not_match = 0;
 782
 783                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 784                         if (regcomp(store.value_regex, value_regex,
 785                                         REG_EXTENDED)) {
 786                                 fprintf(stderr, "Invalid pattern: %s\n",
 787                                         value_regex);
 788                                 free(store.value_regex);
 789                                 ret = 6;
 790                                 goto out_free;
 791                         }
 792                 }
 793
 794                 store.offset[0] = 0;
 795                 store.state = START;
 796                 store.seen = 0;
 797
 798                 /*
 799                  * After this, store.offset will contain the *end* offset
 800                  * of the last match, or remain at 0 if no match was found.
 801                  * As a side effect, we make sure to transform only a valid
 802                  * existing config file.
 803                  */
 804                 if (git_config_from_file(store_aux, config_filename)) {
 805                         fprintf(stderr, "invalid config file\n");
 806                         free(store.key);
 807                         if (store.value_regex != NULL) {
 808                                 regfree(store.value_regex);
 809                                 free(store.value_regex);
 810                         }
 811                         ret = 3;
 812                         goto out_free;
 813                 }
 814
 815                 free(store.key);
 816                 if (store.value_regex != NULL) {
 817                         regfree(store.value_regex);
 818                         free(store.value_regex);
 819                 }
 820
 821                 /* if nothing to unset, or too many matches, error out */
 822                 if ((store.seen == 0 && value == NULL) ||
 823                                 (store.seen > 1 && multi_replace == 0)) {
 824                         ret = 5;
 825                         goto out_free;
 826                 }
 827
 828                 fstat(in_fd, &st);
 829                 contents_sz = xsize_t(st.st_size);
 830                 contents = xmmap(NULL, contents_sz, PROT_READ,
 831                         MAP_PRIVATE, in_fd, 0);
 832                 close(in_fd);
 833
 834                 if (store.seen == 0)
 835                         store.seen = 1;
 836
 837                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 838                         if (store.offset[i] == 0) {
 839                                 store.offset[i] = copy_end = contents_sz;
 840                         } else if (store.state != KEY_SEEN) {
 841                                 copy_end = store.offset[i];
 842                         } else
 843                                 copy_end = find_beginning_of_line(
 844                                         contents, contents_sz,
 845                                         store.offset[i]-2, &new_line);
 846
 847                         /* write the first part of the config */
 848                         if (copy_end > copy_begin) {
 849                                 if (write_in_full(fd, contents + copy_begin,
 850                                                   copy_end - copy_begin) <
 851                                     copy_end - copy_begin)
 852                                         goto write_err_out;
 853                                 if (new_line &&
 854                                     write_in_full(fd, "\n", 1) != 1)
 855                                         goto write_err_out;
 856                         }
 857                         copy_begin = store.offset[i];
 858                 }
 859
 860                 /* write the pair (value == NULL means unset) */
 861                 if (value != NULL) {
 862                         if (store.state == START) {
 863                                 if (!store_write_section(fd, key))
 864                                         goto write_err_out;
 865                         }
 866                         if (!store_write_pair(fd, key, value))
 867                                 goto write_err_out;
 868                 }
 869
 870                 /* write the rest of the config */
 871                 if (copy_begin < contents_sz)
 872                         if (write_in_full(fd, contents + copy_begin,
 873                                           contents_sz - copy_begin) <
 874                             contents_sz - copy_begin)
 875                                 goto write_err_out;
 876
 877                 munmap(contents, contents_sz);
 878                 unlink(config_filename);
 879         }
 880
 881         if (rename(lock_file, config_filename) < 0) {
 882                 fprintf(stderr, "Could not rename the lock file?\n");
 883                 ret = 4;
 884                 goto out_free;
 885         }
 886
 887         ret = 0;
 888
 889 out_free:
 890         if (0 <= fd)
 891                 close(fd);
 892         free(config_filename);
 893         if (lock_file) {
 894                 unlink(lock_file);
 895                 free(lock_file);
 896         }
 897         return ret;
 898
 899 write_err_out:
 900         ret = write_error();
 901         goto out_free;
 902
 903 }
 904
 905 static int section_name_match (const char *buf, const char *name)
 906 {
 907         int i = 0, j = 0, dot = 0;
 908         for (; buf[i] && buf[i] != ']'; i++) {
 909                 if (!dot && isspace(buf[i])) {
 910                         dot = 1;
 911                         if (name[j++] != '.')
 912                                 break;
 913                         for (i++; isspace(buf[i]); i++)
 914                                 ; /* do nothing */
 915                         if (buf[i] != '"')
 916                                 break;
 917                         continue;
 918                 }
 919                 if (buf[i] == '\\' && dot)
 920                         i++;
 921                 else if (buf[i] == '"' && dot) {
 922                         for (i++; isspace(buf[i]); i++)
 923                                 ; /* do_nothing */
 924                         break;
 925                 }
 926                 if (buf[i] != name[j++])
 927                         break;
 928         }
 929         return (buf[i] == ']' && name[j] == 0);
 930 }
 931
 932 /* if new_name == NULL, the section is removed instead */
 933 int git_config_rename_section(const char *old_name, const char *new_name)
 934 {
 935         int ret = 0, remove = 0;
 936         char *config_filename;
 937         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 938         int out_fd;
 939         char buf[1024];
 940
 941         config_filename = getenv(CONFIG_ENVIRONMENT);
 942         if (!config_filename) {
 943                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 944                 if (!config_filename)
 945                         config_filename  = git_path("config");
 946         }
 947         config_filename = xstrdup(config_filename);
 948         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 949         if (out_fd < 0) {
 950                 ret = error("Could not lock config file!");
 951                 goto out;
 952         }
 953
 954         if (!(config_file = fopen(config_filename, "rb"))) {
 955                 /* no config file means nothing to rename, no error */
 956                 goto unlock_and_out;
 957         }
 958
 959         while (fgets(buf, sizeof(buf), config_file)) {
 960                 int i;
 961                 int length;
 962                 for (i = 0; buf[i] && isspace(buf[i]); i++)
 963                         ; /* do nothing */
 964                 if (buf[i] == '[') {
 965                         /* it's a section */
 966                         if (section_name_match (&buf[i+1], old_name)) {
 967                                 ret++;
 968                                 if (new_name == NULL) {
 969                                         remove = 1;
 970                                         continue;
 971                                 }
 972                                 store.baselen = strlen(new_name);
 973                                 if (!store_write_section(out_fd, new_name)) {
 974                                         ret = write_error();
 975                                         goto out;
 976                                 }
 977                                 continue;
 978                         }
 979                         remove = 0;
 980                 }
 981                 if (remove)
 982                         continue;
 983                 length = strlen(buf);
 984                 if (write_in_full(out_fd, buf, length) != length) {
 985                         ret = write_error();
 986                         goto out;
 987                 }
 988         }
 989         fclose(config_file);
 990  unlock_and_out:
 991         if (close(out_fd) || commit_lock_file(lock) < 0)
 992                         ret = error("Cannot commit config file!");
 993  out:
 994         free(config_filename);
 995         return ret;
 996 }