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         if (!strcmp(var, "core.editor")) {
 430                 editor_program = xstrdup(value);
 431                 return 0;
 432         }
 433
 434         /* Add other config variables here and to Documentation/config.txt. */
 435         return 0;
 436 }
 437
 438 int git_config_from_file(config_fn_t fn, const char *filename)
 439 {
 440         int ret;
 441         FILE *f = fopen(filename, "r");
 442
 443         ret = -1;
 444         if (f) {
 445                 config_file = f;
 446                 config_file_name = filename;
 447                 config_linenr = 1;
 448                 ret = git_parse_file(fn);
 449                 fclose(f);
 450                 config_file_name = NULL;
 451         }
 452         return ret;
 453 }
 454
 455 int git_config(config_fn_t fn)
 456 {
 457         int ret = 0;
 458         char *repo_config = NULL;
 459         const char *home = NULL, *filename;
 460
 461         /* $GIT_CONFIG makes git read _only_ the given config file,
 462          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 463          * global config file, the same way it would the per-repository
 464          * config file otherwise. */
 465         filename = getenv(CONFIG_ENVIRONMENT);
 466         if (!filename) {
 467                 if (!access(ETC_GITCONFIG, R_OK))
 468                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 469                 home = getenv("HOME");
 470                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 471                 if (!filename)
 472                         filename = repo_config = xstrdup(git_path("config"));
 473         }
 474
 475         if (home) {
 476                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 477                 if (!access(user_config, R_OK))
 478                         ret = git_config_from_file(fn, user_config);
 479                 free(user_config);
 480         }
 481
 482         ret += git_config_from_file(fn, filename);
 483         free(repo_config);
 484         return ret;
 485 }
 486
 487 /*
 488  * Find all the stuff for git_config_set() below.
 489  */
 490
 491 #define MAX_MATCHES 512
 492
 493 static struct {
 494         int baselen;
 495         char* key;
 496         int do_not_match;
 497         regex_t* value_regex;
 498         int multi_replace;
 499         size_t offset[MAX_MATCHES];
 500         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 501         int seen;
 502 } store;
 503
 504 static int matches(const char* key, const char* value)
 505 {
 506         return !strcmp(key, store.key) &&
 507                 (store.value_regex == NULL ||
 508                  (store.do_not_match ^
 509                   !regexec(store.value_regex, value, 0, NULL, 0)));
 510 }
 511
 512 static int store_aux(const char* key, const char* value)
 513 {
 514         const char *ep;
 515         size_t section_len;
 516
 517         switch (store.state) {
 518         case KEY_SEEN:
 519                 if (matches(key, value)) {
 520                         if (store.seen == 1 && store.multi_replace == 0) {
 521                                 fprintf(stderr,
 522                                         "Warning: %s has multiple values\n",
 523                                         key);
 524                         } else if (store.seen >= MAX_MATCHES) {
 525                                 fprintf(stderr, "Too many matches\n");
 526                                 return 1;
 527                         }
 528
 529                         store.offset[store.seen] = ftell(config_file);
 530                         store.seen++;
 531                 }
 532                 break;
 533         case SECTION_SEEN:
 534                 /*
 535                  * What we are looking for is in store.key (both
 536                  * section and var), and its section part is baselen
 537                  * long.  We found key (again, both section and var).
 538                  * We would want to know if this key is in the same
 539                  * section as what we are looking for.  We already
 540                  * know we are in the same section as what should
 541                  * hold store.key.
 542                  */
 543                 ep = strrchr(key, '.');
 544                 section_len = ep - key;
 545
 546                 if ((section_len != store.baselen) ||
 547                     memcmp(key, store.key, section_len+1)) {
 548                         store.state = SECTION_END_SEEN;
 549                         break;
 550                 }
 551
 552                 /*
 553                  * Do not increment matches: this is no match, but we
 554                  * just made sure we are in the desired section.
 555                  */
 556                 store.offset[store.seen] = ftell(config_file);
 557                 /* fallthru */
 558         case SECTION_END_SEEN:
 559         case START:
 560                 if (matches(key, value)) {
 561                         store.offset[store.seen] = ftell(config_file);
 562                         store.state = KEY_SEEN;
 563                         store.seen++;
 564                 } else {
 565                         if (strrchr(key, '.') - key == store.baselen &&
 566                               !strncmp(key, store.key, store.baselen)) {
 567                                         store.state = SECTION_SEEN;
 568                                         store.offset[store.seen] = ftell(config_file);
 569                         }
 570                 }
 571         }
 572         return 0;
 573 }
 574
 575 static int write_error(void)
 576 {
 577         fprintf(stderr, "Failed to write new configuration file\n");
 578
 579         /* Same error code as "failed to rename". */
 580         return 4;
 581 }
 582
 583 static int store_write_section(int fd, const char* key)
 584 {
 585         const char *dot = strchr(key, '.');
 586         int len1 = store.baselen, len2 = -1;
 587
 588         dot = strchr(key, '.');
 589         if (dot) {
 590                 int dotlen = dot - key;
 591                 if (dotlen < len1) {
 592                         len2 = len1 - dotlen - 1;
 593                         len1 = dotlen;
 594                 }
 595         }
 596
 597         if (write_in_full(fd, "[", 1) != 1 ||
 598             write_in_full(fd, key, len1) != len1)
 599                 return 0;
 600         if (len2 >= 0) {
 601                 if (write_in_full(fd, " \"", 2) != 2)
 602                         return 0;
 603                 while (--len2 >= 0) {
 604                         unsigned char c = *++dot;
 605                         if (c == '"')
 606                                 if (write_in_full(fd, "\\", 1) != 1)
 607                                         return 0;
 608                         if (write_in_full(fd, &c, 1) != 1)
 609                                 return 0;
 610                 }
 611                 if (write_in_full(fd, "\"", 1) != 1)
 612                         return 0;
 613         }
 614         if (write_in_full(fd, "]\n", 2) != 2)
 615                 return 0;
 616
 617         return 1;
 618 }
 619
 620 static int store_write_pair(int fd, const char* key, const char* value)
 621 {
 622         int i;
 623         int length = strlen(key+store.baselen+1);
 624         int quote = 0;
 625
 626         /* Check to see if the value needs to be quoted. */
 627         if (value[0] == ' ')
 628                 quote = 1;
 629         for (i = 0; value[i]; i++)
 630                 if (value[i] == ';' || value[i] == '#')
 631                         quote = 1;
 632         if (value[i-1] == ' ')
 633                 quote = 1;
 634
 635         if (write_in_full(fd, "\t", 1) != 1 ||
 636             write_in_full(fd, key+store.baselen+1, length) != length ||
 637             write_in_full(fd, " = ", 3) != 3)
 638                 return 0;
 639         if (quote && write_in_full(fd, "\"", 1) != 1)
 640                 return 0;
 641         for (i = 0; value[i]; i++)
 642                 switch (value[i]) {
 643                 case '\n':
 644                         if (write_in_full(fd, "\\n", 2) != 2)
 645                                 return 0;
 646                         break;
 647                 case '\t':
 648                         if (write_in_full(fd, "\\t", 2) != 2)
 649                                 return 0;
 650                         break;
 651                 case '"':
 652                 case '\\':
 653                         if (write_in_full(fd, "\\", 1) != 1)
 654                                 return 0;
 655                 default:
 656                         if (write_in_full(fd, value+i, 1) != 1)
 657                                 return 0;
 658                         break;
 659                 }
 660         if (quote && write_in_full(fd, "\"", 1) != 1)
 661                 return 0;
 662         if (write_in_full(fd, "\n", 1) != 1)
 663                 return 0;
 664         return 1;
 665 }
 666
 667 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 668         size_t offset_, int* found_bracket)
 669 {
 670         size_t equal_offset = size, bracket_offset = size;
 671         ssize_t offset;
 672
 673         for (offset = offset_-2; offset > 0
 674                         && contents[offset] != '\n'; offset--)
 675                 switch (contents[offset]) {
 676                         case '=': equal_offset = offset; break;
 677                         case ']': bracket_offset = offset; break;
 678                 }
 679         if (bracket_offset < equal_offset) {
 680                 *found_bracket = 1;
 681                 offset = bracket_offset+1;
 682         } else
 683                 offset++;
 684
 685         return offset;
 686 }
 687
 688 int git_config_set(const char* key, const char* value)
 689 {
 690         return git_config_set_multivar(key, value, NULL, 0);
 691 }
 692
 693 /*
 694  * If value==NULL, unset in (remove from) config,
 695  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 696  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 697  *     else all matching key/values (regardless how many) are removed,
 698  *     before the new pair is written.
 699  *
 700  * Returns 0 on success.
 701  *
 702  * This function does this:
 703  *
 704  * - it locks the config file by creating ".git/config.lock"
 705  *
 706  * - it then parses the config using store_aux() as validator to find
 707  *   the position on the key/value pair to replace. If it is to be unset,
 708  *   it must be found exactly once.
 709  *
 710  * - the config file is mmap()ed and the part before the match (if any) is
 711  *   written to the lock file, then the changed part and the rest.
 712  *
 713  * - the config file is removed and the lock file rename()d to it.
 714  *
 715  */
 716 int git_config_set_multivar(const char* key, const char* value,
 717         const char* value_regex, int multi_replace)
 718 {
 719         int i, dot;
 720         int fd = -1, in_fd;
 721         int ret;
 722         char* config_filename;
 723         struct lock_file *lock = NULL;
 724         const char* last_dot = strrchr(key, '.');
 725
 726         config_filename = getenv(CONFIG_ENVIRONMENT);
 727         if (!config_filename) {
 728                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 729                 if (!config_filename)
 730                         config_filename  = git_path("config");
 731         }
 732         config_filename = xstrdup(config_filename);
 733
 734         /*
 735          * Since "key" actually contains the section name and the real
 736          * key name separated by a dot, we have to know where the dot is.
 737          */
 738
 739         if (last_dot == NULL) {
 740                 fprintf(stderr, "key does not contain a section: %s\n", key);
 741                 ret = 2;
 742                 goto out_free;
 743         }
 744         store.baselen = last_dot - key;
 745
 746         store.multi_replace = multi_replace;
 747
 748         /*
 749          * Validate the key and while at it, lower case it for matching.
 750          */
 751         store.key = xmalloc(strlen(key) + 1);
 752         dot = 0;
 753         for (i = 0; key[i]; i++) {
 754                 unsigned char c = key[i];
 755                 if (c == '.')
 756                         dot = 1;
 757                 /* Leave the extended basename untouched.. */
 758                 if (!dot || i > store.baselen) {
 759                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 760                                 fprintf(stderr, "invalid key: %s\n", key);
 761                                 free(store.key);
 762                                 ret = 1;
 763                                 goto out_free;
 764                         }
 765                         c = tolower(c);
 766                 } else if (c == '\n') {
 767                         fprintf(stderr, "invalid key (newline): %s\n", key);
 768                         free(store.key);
 769                         ret = 1;
 770                         goto out_free;
 771                 }
 772                 store.key[i] = c;
 773         }
 774         store.key[i] = 0;
 775
 776         /*
 777          * The lock serves a purpose in addition to locking: the new
 778          * contents of .git/config will be written into it.
 779          */
 780         lock = xcalloc(sizeof(struct lock_file), 1);
 781         fd = hold_lock_file_for_update(lock, config_filename, 0);
 782         if (fd < 0) {
 783                 fprintf(stderr, "could not lock config file\n");
 784                 free(store.key);
 785                 ret = -1;
 786                 goto out_free;
 787         }
 788
 789         /*
 790          * If .git/config does not exist yet, write a minimal version.
 791          */
 792         in_fd = open(config_filename, O_RDONLY);
 793         if ( in_fd < 0 ) {
 794                 free(store.key);
 795
 796                 if ( ENOENT != errno ) {
 797                         error("opening %s: %s", config_filename,
 798                               strerror(errno));
 799                         ret = 3; /* same as "invalid config file" */
 800                         goto out_free;
 801                 }
 802                 /* if nothing to unset, error out */
 803                 if (value == NULL) {
 804                         ret = 5;
 805                         goto out_free;
 806                 }
 807
 808                 store.key = (char*)key;
 809                 if (!store_write_section(fd, key) ||
 810                     !store_write_pair(fd, key, value))
 811                         goto write_err_out;
 812         } else {
 813                 struct stat st;
 814                 char* contents;
 815                 size_t contents_sz, copy_begin, copy_end;
 816                 int i, new_line = 0;
 817
 818                 if (value_regex == NULL)
 819                         store.value_regex = NULL;
 820                 else {
 821                         if (value_regex[0] == '!') {
 822                                 store.do_not_match = 1;
 823                                 value_regex++;
 824                         } else
 825                                 store.do_not_match = 0;
 826
 827                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 828                         if (regcomp(store.value_regex, value_regex,
 829                                         REG_EXTENDED)) {
 830                                 fprintf(stderr, "Invalid pattern: %s\n",
 831                                         value_regex);
 832                                 free(store.value_regex);
 833                                 ret = 6;
 834                                 goto out_free;
 835                         }
 836                 }
 837
 838                 store.offset[0] = 0;
 839                 store.state = START;
 840                 store.seen = 0;
 841
 842                 /*
 843                  * After this, store.offset will contain the *end* offset
 844                  * of the last match, or remain at 0 if no match was found.
 845                  * As a side effect, we make sure to transform only a valid
 846                  * existing config file.
 847                  */
 848                 if (git_config_from_file(store_aux, config_filename)) {
 849                         fprintf(stderr, "invalid config file\n");
 850                         free(store.key);
 851                         if (store.value_regex != NULL) {
 852                                 regfree(store.value_regex);
 853                                 free(store.value_regex);
 854                         }
 855                         ret = 3;
 856                         goto out_free;
 857                 }
 858
 859                 free(store.key);
 860                 if (store.value_regex != NULL) {
 861                         regfree(store.value_regex);
 862                         free(store.value_regex);
 863                 }
 864
 865                 /* if nothing to unset, or too many matches, error out */
 866                 if ((store.seen == 0 && value == NULL) ||
 867                                 (store.seen > 1 && multi_replace == 0)) {
 868                         ret = 5;
 869                         goto out_free;
 870                 }
 871
 872                 fstat(in_fd, &st);
 873                 contents_sz = xsize_t(st.st_size);
 874                 contents = xmmap(NULL, contents_sz, PROT_READ,
 875                         MAP_PRIVATE, in_fd, 0);
 876                 close(in_fd);
 877
 878                 if (store.seen == 0)
 879                         store.seen = 1;
 880
 881                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 882                         if (store.offset[i] == 0) {
 883                                 store.offset[i] = copy_end = contents_sz;
 884                         } else if (store.state != KEY_SEEN) {
 885                                 copy_end = store.offset[i];
 886                         } else
 887                                 copy_end = find_beginning_of_line(
 888                                         contents, contents_sz,
 889                                         store.offset[i]-2, &new_line);
 890
 891                         /* write the first part of the config */
 892                         if (copy_end > copy_begin) {
 893                                 if (write_in_full(fd, contents + copy_begin,
 894                                                   copy_end - copy_begin) <
 895                                     copy_end - copy_begin)
 896                                         goto write_err_out;
 897                                 if (new_line &&
 898                                     write_in_full(fd, "\n", 1) != 1)
 899                                         goto write_err_out;
 900                         }
 901                         copy_begin = store.offset[i];
 902                 }
 903
 904                 /* write the pair (value == NULL means unset) */
 905                 if (value != NULL) {
 906                         if (store.state == START) {
 907                                 if (!store_write_section(fd, key))
 908                                         goto write_err_out;
 909                         }
 910                         if (!store_write_pair(fd, key, value))
 911                                 goto write_err_out;
 912                 }
 913
 914                 /* write the rest of the config */
 915                 if (copy_begin < contents_sz)
 916                         if (write_in_full(fd, contents + copy_begin,
 917                                           contents_sz - copy_begin) <
 918                             contents_sz - copy_begin)
 919                                 goto write_err_out;
 920
 921                 munmap(contents, contents_sz);
 922         }
 923
 924         if (close(fd) || commit_lock_file(lock) < 0) {
 925                 fprintf(stderr, "Cannot commit config file!\n");
 926                 ret = 4;
 927                 goto out_free;
 928         }
 929
 930         /* fd is closed, so don't try to close it below. */
 931         fd = -1;
 932         /*
 933          * lock is committed, so don't try to roll it back below.
 934          * NOTE: Since lockfile.c keeps a linked list of all created
 935          * lock_file structures, it isn't safe to free(lock).  It's
 936          * better to just leave it hanging around.
 937          */
 938         lock = NULL;
 939         ret = 0;
 940
 941 out_free:
 942         if (0 <= fd)
 943                 close(fd);
 944         if (lock)
 945                 rollback_lock_file(lock);
 946         free(config_filename);
 947         return ret;
 948
 949 write_err_out:
 950         ret = write_error();
 951         goto out_free;
 952
 953 }
 954
 955 static int section_name_match (const char *buf, const char *name)
 956 {
 957         int i = 0, j = 0, dot = 0;
 958         for (; buf[i] && buf[i] != ']'; i++) {
 959                 if (!dot && isspace(buf[i])) {
 960                         dot = 1;
 961                         if (name[j++] != '.')
 962                                 break;
 963                         for (i++; isspace(buf[i]); i++)
 964                                 ; /* do nothing */
 965                         if (buf[i] != '"')
 966                                 break;
 967                         continue;
 968                 }
 969                 if (buf[i] == '\\' && dot)
 970                         i++;
 971                 else if (buf[i] == '"' && dot) {
 972                         for (i++; isspace(buf[i]); i++)
 973                                 ; /* do_nothing */
 974                         break;
 975                 }
 976                 if (buf[i] != name[j++])
 977                         break;
 978         }
 979         return (buf[i] == ']' && name[j] == 0);
 980 }
 981
 982 /* if new_name == NULL, the section is removed instead */
 983 int git_config_rename_section(const char *old_name, const char *new_name)
 984 {
 985         int ret = 0, remove = 0;
 986         char *config_filename;
 987         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 988         int out_fd;
 989         char buf[1024];
 990
 991         config_filename = getenv(CONFIG_ENVIRONMENT);
 992         if (!config_filename) {
 993                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 994                 if (!config_filename)
 995                         config_filename  = git_path("config");
 996         }
 997         config_filename = xstrdup(config_filename);
 998         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 999         if (out_fd < 0) {
1000                 ret = error("Could not lock config file!");
1001                 goto out;
1002         }
1003
1004         if (!(config_file = fopen(config_filename, "rb"))) {
1005                 /* no config file means nothing to rename, no error */
1006                 goto unlock_and_out;
1007         }
1008
1009         while (fgets(buf, sizeof(buf), config_file)) {
1010                 int i;
1011                 int length;
1012                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1013                         ; /* do nothing */
1014                 if (buf[i] == '[') {
1015                         /* it's a section */
1016                         if (section_name_match (&buf[i+1], old_name)) {
1017                                 ret++;
1018                                 if (new_name == NULL) {
1019                                         remove = 1;
1020                                         continue;
1021                                 }
1022                                 store.baselen = strlen(new_name);
1023                                 if (!store_write_section(out_fd, new_name)) {
1024                                         ret = write_error();
1025                                         goto out;
1026                                 }
1027                                 continue;
1028                         }
1029                         remove = 0;
1030                 }
1031                 if (remove)
1032                         continue;
1033                 length = strlen(buf);
1034                 if (write_in_full(out_fd, buf, length) != length) {
1035                         ret = write_error();
1036                         goto out;
1037                 }
1038         }
1039         fclose(config_file);
1040  unlock_and_out:
1041         if (close(out_fd) || commit_lock_file(lock) < 0)
1042                         ret = error("Cannot commit config file!");
1043  out:
1044         free(config_filename);
1045         return ret;
1046 }