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 static unsigned long get_unit_factor(const char *end)
 237 {
 238         if (!*end)
 239                 return 1;
 240         else if (!strcasecmp(end, "k"))
 241                 return 1024;
 242         else if (!strcasecmp(end, "m"))
 243                 return 1024 * 1024;
 244         else if (!strcasecmp(end, "g"))
 245                 return 1024 * 1024 * 1024;
 246         die("unknown unit: '%s'", end);
 247 }
 248
 249 int git_parse_long(const char *value, long *ret)
 250 {
 251         if (value && *value) {
 252                 char *end;
 253                 long val = strtol(value, &end, 0);
 254                 *ret = val * get_unit_factor(end);
 255                 return 1;
 256         }
 257         return 0;
 258 }
 259
 260 int git_parse_ulong(const char *value, unsigned long *ret)
 261 {
 262         if (value && *value) {
 263                 char *end;
 264                 unsigned long val = strtoul(value, &end, 0);
 265                 *ret = val * get_unit_factor(end);
 266                 return 1;
 267         }
 268         return 0;
 269 }
 270
 271 int git_config_int(const char *name, const char *value)
 272 {
 273         long ret;
 274         if (!git_parse_long(value, &ret))
 275                 die("bad config value for '%s' in %s", name, config_file_name);
 276         return ret;
 277 }
 278
 279 unsigned long git_config_ulong(const char *name, const char *value)
 280 {
 281         unsigned long ret;
 282         if (!git_parse_ulong(value, &ret))
 283                 die("bad config value for '%s' in %s", name, config_file_name);
 284         return ret;
 285 }
 286
 287 int git_config_bool(const char *name, const char *value)
 288 {
 289         if (!value)
 290                 return 1;
 291         if (!*value)
 292                 return 0;
 293         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 294                 return 1;
 295         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 296                 return 0;
 297         return git_config_int(name, value) != 0;
 298 }
 299
 300 int git_default_config(const char *var, const char *value)
 301 {
 302         /* This needs a better name */
 303         if (!strcmp(var, "core.filemode")) {
 304                 trust_executable_bit = git_config_bool(var, value);
 305                 return 0;
 306         }
 307
 308         if (!strcmp(var, "core.quotepath")) {
 309                 quote_path_fully = git_config_bool(var, value);
 310                 return 0;
 311         }
 312
 313         if (!strcmp(var, "core.symlinks")) {
 314                 has_symlinks = git_config_bool(var, value);
 315                 return 0;
 316         }
 317
 318         if (!strcmp(var, "core.bare")) {
 319                 is_bare_repository_cfg = git_config_bool(var, value);
 320                 return 0;
 321         }
 322
 323         if (!strcmp(var, "core.ignorestat")) {
 324                 assume_unchanged = git_config_bool(var, value);
 325                 return 0;
 326         }
 327
 328         if (!strcmp(var, "core.prefersymlinkrefs")) {
 329                 prefer_symlink_refs = git_config_bool(var, value);
 330                 return 0;
 331         }
 332
 333         if (!strcmp(var, "core.logallrefupdates")) {
 334                 log_all_ref_updates = git_config_bool(var, value);
 335                 return 0;
 336         }
 337
 338         if (!strcmp(var, "core.warnambiguousrefs")) {
 339                 warn_ambiguous_refs = git_config_bool(var, value);
 340                 return 0;
 341         }
 342
 343         if (!strcmp(var, "core.loosecompression")) {
 344                 int level = git_config_int(var, value);
 345                 if (level == -1)
 346                         level = Z_DEFAULT_COMPRESSION;
 347                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 348                         die("bad zlib compression level %d", level);
 349                 zlib_compression_level = level;
 350                 zlib_compression_seen = 1;
 351                 return 0;
 352         }
 353
 354         if (!strcmp(var, "core.compression")) {
 355                 int level = git_config_int(var, value);
 356                 if (level == -1)
 357                         level = Z_DEFAULT_COMPRESSION;
 358                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 359                         die("bad zlib compression level %d", level);
 360                 core_compression_level = level;
 361                 core_compression_seen = 1;
 362                 if (!zlib_compression_seen)
 363                         zlib_compression_level = level;
 364                 return 0;
 365         }
 366
 367         if (!strcmp(var, "core.packedgitwindowsize")) {
 368                 int pgsz_x2 = getpagesize() * 2;
 369                 packed_git_window_size = git_config_int(var, value);
 370
 371                 /* This value must be multiple of (pagesize * 2) */
 372                 packed_git_window_size /= pgsz_x2;
 373                 if (packed_git_window_size < 1)
 374                         packed_git_window_size = 1;
 375                 packed_git_window_size *= pgsz_x2;
 376                 return 0;
 377         }
 378
 379         if (!strcmp(var, "core.packedgitlimit")) {
 380                 packed_git_limit = git_config_int(var, value);
 381                 return 0;
 382         }
 383
 384         if (!strcmp(var, "core.deltabasecachelimit")) {
 385                 delta_base_cache_limit = git_config_int(var, value);
 386                 return 0;
 387         }
 388
 389         if (!strcmp(var, "core.autocrlf")) {
 390                 if (value && !strcasecmp(value, "input")) {
 391                         auto_crlf = -1;
 392                         return 0;
 393                 }
 394                 auto_crlf = git_config_bool(var, value);
 395                 return 0;
 396         }
 397
 398         if (!strcmp(var, "user.name")) {
 399                 strlcpy(git_default_name, value, sizeof(git_default_name));
 400                 return 0;
 401         }
 402
 403         if (!strcmp(var, "user.email")) {
 404                 strlcpy(git_default_email, value, sizeof(git_default_email));
 405                 return 0;
 406         }
 407
 408         if (!strcmp(var, "i18n.commitencoding")) {
 409                 git_commit_encoding = xstrdup(value);
 410                 return 0;
 411         }
 412
 413         if (!strcmp(var, "i18n.logoutputencoding")) {
 414                 git_log_output_encoding = xstrdup(value);
 415                 return 0;
 416         }
 417
 418
 419         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 420                 pager_use_color = git_config_bool(var,value);
 421                 return 0;
 422         }
 423
 424         if (!strcmp(var, "core.pager")) {
 425                 pager_program = xstrdup(value);
 426                 return 0;
 427         }
 428
 429         /* Add other config variables here and to Documentation/config.txt. */
 430         return 0;
 431 }
 432
 433 int git_config_from_file(config_fn_t fn, const char *filename)
 434 {
 435         int ret;
 436         FILE *f = fopen(filename, "r");
 437
 438         ret = -1;
 439         if (f) {
 440                 config_file = f;
 441                 config_file_name = filename;
 442                 config_linenr = 1;
 443                 ret = git_parse_file(fn);
 444                 fclose(f);
 445                 config_file_name = NULL;
 446         }
 447         return ret;
 448 }
 449
 450 int git_config(config_fn_t fn)
 451 {
 452         int ret = 0;
 453         char *repo_config = NULL;
 454         const char *home = NULL, *filename;
 455
 456         /* $GIT_CONFIG makes git read _only_ the given config file,
 457          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 458          * global config file, the same way it would the per-repository
 459          * config file otherwise. */
 460         filename = getenv(CONFIG_ENVIRONMENT);
 461         if (!filename) {
 462                 if (!access(ETC_GITCONFIG, R_OK))
 463                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 464                 home = getenv("HOME");
 465                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 466                 if (!filename)
 467                         filename = repo_config = xstrdup(git_path("config"));
 468         }
 469
 470         if (home) {
 471                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 472                 if (!access(user_config, R_OK))
 473                         ret = git_config_from_file(fn, user_config);
 474                 free(user_config);
 475         }
 476
 477         ret += git_config_from_file(fn, filename);
 478         free(repo_config);
 479         return ret;
 480 }
 481
 482 /*
 483  * Find all the stuff for git_config_set() below.
 484  */
 485
 486 #define MAX_MATCHES 512
 487
 488 static struct {
 489         int baselen;
 490         char* key;
 491         int do_not_match;
 492         regex_t* value_regex;
 493         int multi_replace;
 494         size_t offset[MAX_MATCHES];
 495         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 496         int seen;
 497 } store;
 498
 499 static int matches(const char* key, const char* value)
 500 {
 501         return !strcmp(key, store.key) &&
 502                 (store.value_regex == NULL ||
 503                  (store.do_not_match ^
 504                   !regexec(store.value_regex, value, 0, NULL, 0)));
 505 }
 506
 507 static int store_aux(const char* key, const char* value)
 508 {
 509         const char *ep;
 510         size_t section_len;
 511
 512         switch (store.state) {
 513         case KEY_SEEN:
 514                 if (matches(key, value)) {
 515                         if (store.seen == 1 && store.multi_replace == 0) {
 516                                 fprintf(stderr,
 517                                         "Warning: %s has multiple values\n",
 518                                         key);
 519                         } else if (store.seen >= MAX_MATCHES) {
 520                                 fprintf(stderr, "Too many matches\n");
 521                                 return 1;
 522                         }
 523
 524                         store.offset[store.seen] = ftell(config_file);
 525                         store.seen++;
 526                 }
 527                 break;
 528         case SECTION_SEEN:
 529                 /*
 530                  * What we are looking for is in store.key (both
 531                  * section and var), and its section part is baselen
 532                  * long.  We found key (again, both section and var).
 533                  * We would want to know if this key is in the same
 534                  * section as what we are looking for.  We already
 535                  * know we are in the same section as what should
 536                  * hold store.key.
 537                  */
 538                 ep = strrchr(key, '.');
 539                 section_len = ep - key;
 540
 541                 if ((section_len != store.baselen) ||
 542                     memcmp(key, store.key, section_len+1)) {
 543                         store.state = SECTION_END_SEEN;
 544                         break;
 545                 }
 546
 547                 /*
 548                  * Do not increment matches: this is no match, but we
 549                  * just made sure we are in the desired section.
 550                  */
 551                 store.offset[store.seen] = ftell(config_file);
 552                 /* fallthru */
 553         case SECTION_END_SEEN:
 554         case START:
 555                 if (matches(key, value)) {
 556                         store.offset[store.seen] = ftell(config_file);
 557                         store.state = KEY_SEEN;
 558                         store.seen++;
 559                 } else {
 560                         if (strrchr(key, '.') - key == store.baselen &&
 561                               !strncmp(key, store.key, store.baselen)) {
 562                                         store.state = SECTION_SEEN;
 563                                         store.offset[store.seen] = ftell(config_file);
 564                         }
 565                 }
 566         }
 567         return 0;
 568 }
 569
 570 static int write_error(void)
 571 {
 572         fprintf(stderr, "Failed to write new configuration file\n");
 573
 574         /* Same error code as "failed to rename". */
 575         return 4;
 576 }
 577
 578 static int store_write_section(int fd, const char* key)
 579 {
 580         const char *dot = strchr(key, '.');
 581         int len1 = store.baselen, len2 = -1;
 582
 583         dot = strchr(key, '.');
 584         if (dot) {
 585                 int dotlen = dot - key;
 586                 if (dotlen < len1) {
 587                         len2 = len1 - dotlen - 1;
 588                         len1 = dotlen;
 589                 }
 590         }
 591
 592         if (write_in_full(fd, "[", 1) != 1 ||
 593             write_in_full(fd, key, len1) != len1)
 594                 return 0;
 595         if (len2 >= 0) {
 596                 if (write_in_full(fd, " \"", 2) != 2)
 597                         return 0;
 598                 while (--len2 >= 0) {
 599                         unsigned char c = *++dot;
 600                         if (c == '"')
 601                                 if (write_in_full(fd, "\\", 1) != 1)
 602                                         return 0;
 603                         if (write_in_full(fd, &c, 1) != 1)
 604                                 return 0;
 605                 }
 606                 if (write_in_full(fd, "\"", 1) != 1)
 607                         return 0;
 608         }
 609         if (write_in_full(fd, "]\n", 2) != 2)
 610                 return 0;
 611
 612         return 1;
 613 }
 614
 615 static int store_write_pair(int fd, const char* key, const char* value)
 616 {
 617         int i;
 618         int length = strlen(key+store.baselen+1);
 619         int quote = 0;
 620
 621         /* Check to see if the value needs to be quoted. */
 622         if (value[0] == ' ')
 623                 quote = 1;
 624         for (i = 0; value[i]; i++)
 625                 if (value[i] == ';' || value[i] == '#')
 626                         quote = 1;
 627         if (value[i-1] == ' ')
 628                 quote = 1;
 629
 630         if (write_in_full(fd, "\t", 1) != 1 ||
 631             write_in_full(fd, key+store.baselen+1, length) != length ||
 632             write_in_full(fd, " = ", 3) != 3)
 633                 return 0;
 634         if (quote && write_in_full(fd, "\"", 1) != 1)
 635                 return 0;
 636         for (i = 0; value[i]; i++)
 637                 switch (value[i]) {
 638                 case '\n':
 639                         if (write_in_full(fd, "\\n", 2) != 2)
 640                                 return 0;
 641                         break;
 642                 case '\t':
 643                         if (write_in_full(fd, "\\t", 2) != 2)
 644                                 return 0;
 645                         break;
 646                 case '"':
 647                 case '\\':
 648                         if (write_in_full(fd, "\\", 1) != 1)
 649                                 return 0;
 650                 default:
 651                         if (write_in_full(fd, value+i, 1) != 1)
 652                                 return 0;
 653                         break;
 654                 }
 655         if (quote && write_in_full(fd, "\"", 1) != 1)
 656                 return 0;
 657         if (write_in_full(fd, "\n", 1) != 1)
 658                 return 0;
 659         return 1;
 660 }
 661
 662 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 663         size_t offset_, int* found_bracket)
 664 {
 665         size_t equal_offset = size, bracket_offset = size;
 666         ssize_t offset;
 667
 668         for (offset = offset_-2; offset > 0
 669                         && contents[offset] != '\n'; offset--)
 670                 switch (contents[offset]) {
 671                         case '=': equal_offset = offset; break;
 672                         case ']': bracket_offset = offset; break;
 673                 }
 674         if (bracket_offset < equal_offset) {
 675                 *found_bracket = 1;
 676                 offset = bracket_offset+1;
 677         } else
 678                 offset++;
 679
 680         return offset;
 681 }
 682
 683 int git_config_set(const char* key, const char* value)
 684 {
 685         return git_config_set_multivar(key, value, NULL, 0);
 686 }
 687
 688 /*
 689  * If value==NULL, unset in (remove from) config,
 690  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 691  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 692  *     else all matching key/values (regardless how many) are removed,
 693  *     before the new pair is written.
 694  *
 695  * Returns 0 on success.
 696  *
 697  * This function does this:
 698  *
 699  * - it locks the config file by creating ".git/config.lock"
 700  *
 701  * - it then parses the config using store_aux() as validator to find
 702  *   the position on the key/value pair to replace. If it is to be unset,
 703  *   it must be found exactly once.
 704  *
 705  * - the config file is mmap()ed and the part before the match (if any) is
 706  *   written to the lock file, then the changed part and the rest.
 707  *
 708  * - the config file is removed and the lock file rename()d to it.
 709  *
 710  */
 711 int git_config_set_multivar(const char* key, const char* value,
 712         const char* value_regex, int multi_replace)
 713 {
 714         int i, dot;
 715         int fd = -1, in_fd;
 716         int ret;
 717         char* config_filename;
 718         struct lock_file *lock = NULL;
 719         const char* last_dot = strrchr(key, '.');
 720
 721         config_filename = getenv(CONFIG_ENVIRONMENT);
 722         if (!config_filename) {
 723                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 724                 if (!config_filename)
 725                         config_filename  = git_path("config");
 726         }
 727         config_filename = xstrdup(config_filename);
 728
 729         /*
 730          * Since "key" actually contains the section name and the real
 731          * key name separated by a dot, we have to know where the dot is.
 732          */
 733
 734         if (last_dot == NULL) {
 735                 fprintf(stderr, "key does not contain a section: %s\n", key);
 736                 ret = 2;
 737                 goto out_free;
 738         }
 739         store.baselen = last_dot - key;
 740
 741         store.multi_replace = multi_replace;
 742
 743         /*
 744          * Validate the key and while at it, lower case it for matching.
 745          */
 746         store.key = xmalloc(strlen(key) + 1);
 747         dot = 0;
 748         for (i = 0; key[i]; i++) {
 749                 unsigned char c = key[i];
 750                 if (c == '.')
 751                         dot = 1;
 752                 /* Leave the extended basename untouched.. */
 753                 if (!dot || i > store.baselen) {
 754                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 755                                 fprintf(stderr, "invalid key: %s\n", key);
 756                                 free(store.key);
 757                                 ret = 1;
 758                                 goto out_free;
 759                         }
 760                         c = tolower(c);
 761                 } else if (c == '\n') {
 762                         fprintf(stderr, "invalid key (newline): %s\n", key);
 763                         free(store.key);
 764                         ret = 1;
 765                         goto out_free;
 766                 }
 767                 store.key[i] = c;
 768         }
 769         store.key[i] = 0;
 770
 771         /*
 772          * The lock serves a purpose in addition to locking: the new
 773          * contents of .git/config will be written into it.
 774          */
 775         lock = xcalloc(sizeof(struct lock_file), 1);
 776         fd = hold_lock_file_for_update(lock, config_filename, 0);
 777         if (fd < 0) {
 778                 fprintf(stderr, "could not lock config file\n");
 779                 free(store.key);
 780                 ret = -1;
 781                 goto out_free;
 782         }
 783
 784         /*
 785          * If .git/config does not exist yet, write a minimal version.
 786          */
 787         in_fd = open(config_filename, O_RDONLY);
 788         if ( in_fd < 0 ) {
 789                 free(store.key);
 790
 791                 if ( ENOENT != errno ) {
 792                         error("opening %s: %s", config_filename,
 793                               strerror(errno));
 794                         ret = 3; /* same as "invalid config file" */
 795                         goto out_free;
 796                 }
 797                 /* if nothing to unset, error out */
 798                 if (value == NULL) {
 799                         ret = 5;
 800                         goto out_free;
 801                 }
 802
 803                 store.key = (char*)key;
 804                 if (!store_write_section(fd, key) ||
 805                     !store_write_pair(fd, key, value))
 806                         goto write_err_out;
 807         } else {
 808                 struct stat st;
 809                 char* contents;
 810                 size_t contents_sz, copy_begin, copy_end;
 811                 int i, new_line = 0;
 812
 813                 if (value_regex == NULL)
 814                         store.value_regex = NULL;
 815                 else {
 816                         if (value_regex[0] == '!') {
 817                                 store.do_not_match = 1;
 818                                 value_regex++;
 819                         } else
 820                                 store.do_not_match = 0;
 821
 822                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 823                         if (regcomp(store.value_regex, value_regex,
 824                                         REG_EXTENDED)) {
 825                                 fprintf(stderr, "Invalid pattern: %s\n",
 826                                         value_regex);
 827                                 free(store.value_regex);
 828                                 ret = 6;
 829                                 goto out_free;
 830                         }
 831                 }
 832
 833                 store.offset[0] = 0;
 834                 store.state = START;
 835                 store.seen = 0;
 836
 837                 /*
 838                  * After this, store.offset will contain the *end* offset
 839                  * of the last match, or remain at 0 if no match was found.
 840                  * As a side effect, we make sure to transform only a valid
 841                  * existing config file.
 842                  */
 843                 if (git_config_from_file(store_aux, config_filename)) {
 844                         fprintf(stderr, "invalid config file\n");
 845                         free(store.key);
 846                         if (store.value_regex != NULL) {
 847                                 regfree(store.value_regex);
 848                                 free(store.value_regex);
 849                         }
 850                         ret = 3;
 851                         goto out_free;
 852                 }
 853
 854                 free(store.key);
 855                 if (store.value_regex != NULL) {
 856                         regfree(store.value_regex);
 857                         free(store.value_regex);
 858                 }
 859
 860                 /* if nothing to unset, or too many matches, error out */
 861                 if ((store.seen == 0 && value == NULL) ||
 862                                 (store.seen > 1 && multi_replace == 0)) {
 863                         ret = 5;
 864                         goto out_free;
 865                 }
 866
 867                 fstat(in_fd, &st);
 868                 contents_sz = xsize_t(st.st_size);
 869                 contents = xmmap(NULL, contents_sz, PROT_READ,
 870                         MAP_PRIVATE, in_fd, 0);
 871                 close(in_fd);
 872
 873                 if (store.seen == 0)
 874                         store.seen = 1;
 875
 876                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 877                         if (store.offset[i] == 0) {
 878                                 store.offset[i] = copy_end = contents_sz;
 879                         } else if (store.state != KEY_SEEN) {
 880                                 copy_end = store.offset[i];
 881                         } else
 882                                 copy_end = find_beginning_of_line(
 883                                         contents, contents_sz,
 884                                         store.offset[i]-2, &new_line);
 885
 886                         /* write the first part of the config */
 887                         if (copy_end > copy_begin) {
 888                                 if (write_in_full(fd, contents + copy_begin,
 889                                                   copy_end - copy_begin) <
 890                                     copy_end - copy_begin)
 891                                         goto write_err_out;
 892                                 if (new_line &&
 893                                     write_in_full(fd, "\n", 1) != 1)
 894                                         goto write_err_out;
 895                         }
 896                         copy_begin = store.offset[i];
 897                 }
 898
 899                 /* write the pair (value == NULL means unset) */
 900                 if (value != NULL) {
 901                         if (store.state == START) {
 902                                 if (!store_write_section(fd, key))
 903                                         goto write_err_out;
 904                         }
 905                         if (!store_write_pair(fd, key, value))
 906                                 goto write_err_out;
 907                 }
 908
 909                 /* write the rest of the config */
 910                 if (copy_begin < contents_sz)
 911                         if (write_in_full(fd, contents + copy_begin,
 912                                           contents_sz - copy_begin) <
 913                             contents_sz - copy_begin)
 914                                 goto write_err_out;
 915
 916                 munmap(contents, contents_sz);
 917         }
 918
 919         if (close(fd) || commit_lock_file(lock) < 0) {
 920                 fprintf(stderr, "Cannot commit config file!\n");
 921                 ret = 4;
 922                 goto out_free;
 923         }
 924
 925         /* fd is closed, so don't try to close it below. */
 926         fd = -1;
 927         /*
 928          * lock is committed, so don't try to roll it back below.
 929          * NOTE: Since lockfile.c keeps a linked list of all created
 930          * lock_file structures, it isn't safe to free(lock).  It's
 931          * better to just leave it hanging around.
 932          */
 933         lock = NULL;
 934         ret = 0;
 935
 936 out_free:
 937         if (0 <= fd)
 938                 close(fd);
 939         if (lock)
 940                 rollback_lock_file(lock);
 941         free(config_filename);
 942         return ret;
 943
 944 write_err_out:
 945         ret = write_error();
 946         goto out_free;
 947
 948 }
 949
 950 static int section_name_match (const char *buf, const char *name)
 951 {
 952         int i = 0, j = 0, dot = 0;
 953         for (; buf[i] && buf[i] != ']'; i++) {
 954                 if (!dot && isspace(buf[i])) {
 955                         dot = 1;
 956                         if (name[j++] != '.')
 957                                 break;
 958                         for (i++; isspace(buf[i]); i++)
 959                                 ; /* do nothing */
 960                         if (buf[i] != '"')
 961                                 break;
 962                         continue;
 963                 }
 964                 if (buf[i] == '\\' && dot)
 965                         i++;
 966                 else if (buf[i] == '"' && dot) {
 967                         for (i++; isspace(buf[i]); i++)
 968                                 ; /* do_nothing */
 969                         break;
 970                 }
 971                 if (buf[i] != name[j++])
 972                         break;
 973         }
 974         return (buf[i] == ']' && name[j] == 0);
 975 }
 976
 977 /* if new_name == NULL, the section is removed instead */
 978 int git_config_rename_section(const char *old_name, const char *new_name)
 979 {
 980         int ret = 0, remove = 0;
 981         char *config_filename;
 982         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 983         int out_fd;
 984         char buf[1024];
 985
 986         config_filename = getenv(CONFIG_ENVIRONMENT);
 987         if (!config_filename) {
 988                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 989                 if (!config_filename)
 990                         config_filename  = git_path("config");
 991         }
 992         config_filename = xstrdup(config_filename);
 993         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 994         if (out_fd < 0) {
 995                 ret = error("Could not lock config file!");
 996                 goto out;
 997         }
 998
 999         if (!(config_file = fopen(config_filename, "rb"))) {
1000                 /* no config file means nothing to rename, no error */
1001                 goto unlock_and_out;
1002         }
1003
1004         while (fgets(buf, sizeof(buf), config_file)) {
1005                 int i;
1006                 int length;
1007                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1008                         ; /* do nothing */
1009                 if (buf[i] == '[') {
1010                         /* it's a section */
1011                         if (section_name_match (&buf[i+1], old_name)) {
1012                                 ret++;
1013                                 if (new_name == NULL) {
1014                                         remove = 1;
1015                                         continue;
1016                                 }
1017                                 store.baselen = strlen(new_name);
1018                                 if (!store_write_section(out_fd, new_name)) {
1019                                         ret = write_error();
1020                                         goto out;
1021                                 }
1022                                 continue;
1023                         }
1024                         remove = 0;
1025                 }
1026                 if (remove)
1027                         continue;
1028                 length = strlen(buf);
1029                 if (write_in_full(out_fd, buf, length) != length) {
1030                         ret = write_error();
1031                         goto out;
1032                 }
1033         }
1034         fclose(config_file);
1035  unlock_and_out:
1036         if (close(out_fd) || commit_lock_file(lock) < 0)
1037                         ret = error("Cannot commit config file!");
1038  out:
1039         free(config_filename);
1040         return ret;
1041 }