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 #include "exec_cmd.h"
  10
  11 #define MAXNAME (256)
  12
  13 static FILE *config_file;
  14 static const char *config_file_name;
  15 static int config_linenr;
  16 static int get_next_char(void)
  17 {
  18         int c;
  19         FILE *f;
  20
  21         c = '\n';
  22         if ((f = config_file) != NULL) {
  23                 c = fgetc(f);
  24                 if (c == '\r') {
  25                         /* DOS like systems */
  26                         c = fgetc(f);
  27                         if (c != '\n') {
  28                                 ungetc(c, f);
  29                                 c = '\r';
  30                         }
  31                 }
  32                 if (c == '\n')
  33                         config_linenr++;
  34                 if (c == EOF) {
  35                         config_file = NULL;
  36                         c = '\n';
  37                 }
  38         }
  39         return c;
  40 }
  41
  42 static char *parse_value(void)
  43 {
  44         static char value[1024];
  45         int quote = 0, comment = 0, len = 0, space = 0;
  46
  47         for (;;) {
  48                 int c = get_next_char();
  49                 if (len >= sizeof(value))
  50                         return NULL;
  51                 if (c == '\n') {
  52                         if (quote)
  53                                 return NULL;
  54                         value[len] = 0;
  55                         return value;
  56                 }
  57                 if (comment)
  58                         continue;
  59                 if (isspace(c) && !quote) {
  60                         space = 1;
  61                         continue;
  62                 }
  63                 if (!quote) {
  64                         if (c == ';' || c == '#') {
  65                                 comment = 1;
  66                                 continue;
  67                         }
  68                 }
  69                 if (space) {
  70                         if (len)
  71                                 value[len++] = ' ';
  72                         space = 0;
  73                 }
  74                 if (c == '\\') {
  75                         c = get_next_char();
  76                         switch (c) {
  77                         case '\n':
  78                                 continue;
  79                         case 't':
  80                                 c = '\t';
  81                                 break;
  82                         case 'b':
  83                                 c = '\b';
  84                                 break;
  85                         case 'n':
  86                                 c = '\n';
  87                                 break;
  88                         /* Some characters escape as themselves */
  89                         case '\\': case '"':
  90                                 break;
  91                         /* Reject unknown escape sequences */
  92                         default:
  93                                 return NULL;
  94                         }
  95                         value[len++] = c;
  96                         continue;
  97                 }
  98                 if (c == '"') {
  99                         quote = 1-quote;
 100                         continue;
 101                 }
 102                 value[len++] = c;
 103         }
 104 }
 105
 106 static inline int iskeychar(int c)
 107 {
 108         return isalnum(c) || c == '-';
 109 }
 110
 111 static int get_value(config_fn_t fn, char *name, unsigned int len)
 112 {
 113         int c;
 114         char *value;
 115
 116         /* Get the full name */
 117         for (;;) {
 118                 c = get_next_char();
 119                 if (c == EOF)
 120                         break;
 121                 if (!iskeychar(c))
 122                         break;
 123                 name[len++] = tolower(c);
 124                 if (len >= MAXNAME)
 125                         return -1;
 126         }
 127         name[len] = 0;
 128         while (c == ' ' || c == '\t')
 129                 c = get_next_char();
 130
 131         value = NULL;
 132         if (c != '\n') {
 133                 if (c != '=')
 134                         return -1;
 135                 value = parse_value();
 136                 if (!value)
 137                         return -1;
 138         }
 139         return fn(name, value);
 140 }
 141
 142 static int get_extended_base_var(char *name, int baselen, int c)
 143 {
 144         do {
 145                 if (c == '\n')
 146                         return -1;
 147                 c = get_next_char();
 148         } while (isspace(c));
 149
 150         /* We require the format to be '[base "extension"]' */
 151         if (c != '"')
 152                 return -1;
 153         name[baselen++] = '.';
 154
 155         for (;;) {
 156                 int c = get_next_char();
 157                 if (c == '\n')
 158                         return -1;
 159                 if (c == '"')
 160                         break;
 161                 if (c == '\\') {
 162                         c = get_next_char();
 163                         if (c == '\n')
 164                                 return -1;
 165                 }
 166                 name[baselen++] = c;
 167                 if (baselen > MAXNAME / 2)
 168                         return -1;
 169         }
 170
 171         /* Final ']' */
 172         if (get_next_char() != ']')
 173                 return -1;
 174         return baselen;
 175 }
 176
 177 static int get_base_var(char *name)
 178 {
 179         int baselen = 0;
 180
 181         for (;;) {
 182                 int c = get_next_char();
 183                 if (c == EOF)
 184                         return -1;
 185                 if (c == ']')
 186                         return baselen;
 187                 if (isspace(c))
 188                         return get_extended_base_var(name, baselen, c);
 189                 if (!iskeychar(c) && c != '.')
 190                         return -1;
 191                 if (baselen > MAXNAME / 2)
 192                         return -1;
 193                 name[baselen++] = tolower(c);
 194         }
 195 }
 196
 197 static int git_parse_file(config_fn_t fn)
 198 {
 199         int comment = 0;
 200         int baselen = 0;
 201         static char var[MAXNAME];
 202
 203         for (;;) {
 204                 int c = get_next_char();
 205                 if (c == '\n') {
 206                         /* EOF? */
 207                         if (!config_file)
 208                                 return 0;
 209                         comment = 0;
 210                         continue;
 211                 }
 212                 if (comment || isspace(c))
 213                         continue;
 214                 if (c == '#' || c == ';') {
 215                         comment = 1;
 216                         continue;
 217                 }
 218                 if (c == '[') {
 219                         baselen = get_base_var(var);
 220                         if (baselen <= 0)
 221                                 break;
 222                         var[baselen++] = '.';
 223                         var[baselen] = 0;
 224                         continue;
 225                 }
 226                 if (!isalpha(c))
 227                         break;
 228                 var[baselen] = tolower(c);
 229                 if (get_value(fn, var, baselen+1) < 0)
 230                         break;
 231         }
 232         die("bad config file line %d in %s", config_linenr, config_file_name);
 233 }
 234
 235 int git_config_int(const char *name, const char *value)
 236 {
 237         if (value && *value) {
 238                 char *end;
 239                 int val = strtol(value, &end, 0);
 240                 if (!*end)
 241                         return val;
 242                 if (!strcasecmp(end, "k"))
 243                         return val * 1024;
 244                 if (!strcasecmp(end, "m"))
 245                         return val * 1024 * 1024;
 246                 if (!strcasecmp(end, "g"))
 247                         return val * 1024 * 1024 * 1024;
 248         }
 249         die("bad config value for '%s' in %s", name, config_file_name);
 250 }
 251
 252 int git_config_bool(const char *name, const char *value)
 253 {
 254         if (!value)
 255                 return 1;
 256         if (!*value)
 257                 return 0;
 258         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 259                 return 1;
 260         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 261                 return 0;
 262         return git_config_int(name, value) != 0;
 263 }
 264
 265 int git_default_config(const char *var, const char *value)
 266 {
 267         /* This needs a better name */
 268         if (!strcmp(var, "core.filemode")) {
 269                 trust_executable_bit = git_config_bool(var, value);
 270                 return 0;
 271         }
 272
 273         if (!strcmp(var, "core.symlinks")) {
 274                 has_symlinks = git_config_bool(var, value);
 275                 return 0;
 276         }
 277
 278         if (!strcmp(var, "core.bare")) {
 279                 is_bare_repository_cfg = git_config_bool(var, value);
 280                 return 0;
 281         }
 282
 283         if (!strcmp(var, "core.ignorestat")) {
 284                 assume_unchanged = git_config_bool(var, value);
 285                 return 0;
 286         }
 287
 288         if (!strcmp(var, "core.prefersymlinkrefs")) {
 289                 prefer_symlink_refs = git_config_bool(var, value);
 290                 return 0;
 291         }
 292
 293         if (!strcmp(var, "core.logallrefupdates")) {
 294                 log_all_ref_updates = git_config_bool(var, value);
 295                 return 0;
 296         }
 297
 298         if (!strcmp(var, "core.warnambiguousrefs")) {
 299                 warn_ambiguous_refs = git_config_bool(var, value);
 300                 return 0;
 301         }
 302
 303         if (!strcmp(var, "core.legacyheaders")) {
 304                 use_legacy_headers = git_config_bool(var, value);
 305                 return 0;
 306         }
 307
 308         if (!strcmp(var, "core.compression")) {
 309                 int level = git_config_int(var, value);
 310                 if (level == -1)
 311                         level = Z_DEFAULT_COMPRESSION;
 312                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 313                         die("bad zlib compression level %d", level);
 314                 zlib_compression_level = level;
 315                 return 0;
 316         }
 317
 318         if (!strcmp(var, "core.packedgitwindowsize")) {
 319                 int pgsz_x2 = getpagesize() * 2;
 320                 packed_git_window_size = git_config_int(var, value);
 321
 322                 /* This value must be multiple of (pagesize * 2) */
 323                 packed_git_window_size /= pgsz_x2;
 324                 if (packed_git_window_size < 1)
 325                         packed_git_window_size = 1;
 326                 packed_git_window_size *= pgsz_x2;
 327                 return 0;
 328         }
 329
 330         if (!strcmp(var, "core.packedgitlimit")) {
 331                 packed_git_limit = git_config_int(var, value);
 332                 return 0;
 333         }
 334
 335         if (!strcmp(var, "core.deltabasecachelimit")) {
 336                 delta_base_cache_limit = git_config_int(var, value);
 337                 return 0;
 338         }
 339
 340         if (!strcmp(var, "core.autocrlf")) {
 341                 if (value && !strcasecmp(value, "input")) {
 342                         auto_crlf = -1;
 343                         return 0;
 344                 }
 345                 auto_crlf = git_config_bool(var, value);
 346                 return 0;
 347         }
 348
 349         if (!strcmp(var, "user.name")) {
 350                 strlcpy(git_default_name, value, sizeof(git_default_name));
 351                 return 0;
 352         }
 353
 354         if (!strcmp(var, "user.email")) {
 355                 strlcpy(git_default_email, value, sizeof(git_default_email));
 356                 return 0;
 357         }
 358
 359         if (!strcmp(var, "i18n.commitencoding")) {
 360                 git_commit_encoding = xstrdup(value);
 361                 return 0;
 362         }
 363
 364         if (!strcmp(var, "i18n.logoutputencoding")) {
 365                 git_log_output_encoding = xstrdup(value);
 366                 return 0;
 367         }
 368
 369
 370         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 371                 pager_use_color = git_config_bool(var,value);
 372                 return 0;
 373         }
 374
 375         /* Add other config variables here and to Documentation/config.txt. */
 376         return 0;
 377 }
 378
 379 int git_config_from_file(config_fn_t fn, const char *filename)
 380 {
 381         int ret;
 382         FILE *f = fopen(filename, "r");
 383
 384         ret = -1;
 385         if (f) {
 386                 config_file = f;
 387                 config_file_name = filename;
 388                 config_linenr = 1;
 389                 ret = git_parse_file(fn);
 390                 fclose(f);
 391                 config_file_name = NULL;
 392         }
 393         return ret;
 394 }
 395
 396 const char *git_etc_gitconfig(void)
 397 {
 398         return ETC_GITCONFIG;
 399 }
 400
 401 int git_config(config_fn_t fn)
 402 {
 403         int ret = 0;
 404         char *repo_config = NULL;
 405         const char *home = NULL, *filename;
 406
 407         /* $GIT_CONFIG makes git read _only_ the given config file,
 408          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 409          * global config file, the same way it would the per-repository
 410          * config file otherwise. */
 411         filename = getenv(CONFIG_ENVIRONMENT);
 412         if (!filename) {
 413                 if (!access(git_etc_gitconfig(), R_OK))
 414                         ret += git_config_from_file(fn, git_etc_gitconfig());
 415                 home = getenv("HOME");
 416                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 417                 if (!filename)
 418                         filename = repo_config = xstrdup(git_path("config"));
 419         }
 420
 421         if (home) {
 422                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 423                 if (!access(user_config, R_OK))
 424                         ret = git_config_from_file(fn, user_config);
 425                 free(user_config);
 426         }
 427
 428         ret += git_config_from_file(fn, filename);
 429         free(repo_config);
 430         return ret;
 431 }
 432
 433 /*
 434  * Find all the stuff for git_config_set() below.
 435  */
 436
 437 #define MAX_MATCHES 512
 438
 439 static struct {
 440         int baselen;
 441         char* key;
 442         int do_not_match;
 443         regex_t* value_regex;
 444         int multi_replace;
 445         size_t offset[MAX_MATCHES];
 446         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 447         int seen;
 448 } store;
 449
 450 static int matches(const char* key, const char* value)
 451 {
 452         return !strcmp(key, store.key) &&
 453                 (store.value_regex == NULL ||
 454                  (store.do_not_match ^
 455                   !regexec(store.value_regex, value, 0, NULL, 0)));
 456 }
 457
 458 static int store_aux(const char* key, const char* value)
 459 {
 460         const char *ep;
 461         size_t section_len;
 462
 463         switch (store.state) {
 464         case KEY_SEEN:
 465                 if (matches(key, value)) {
 466                         if (store.seen == 1 && store.multi_replace == 0) {
 467                                 fprintf(stderr,
 468                                         "Warning: %s has multiple values\n",
 469                                         key);
 470                         } else if (store.seen >= MAX_MATCHES) {
 471                                 fprintf(stderr, "Too many matches\n");
 472                                 return 1;
 473                         }
 474
 475                         store.offset[store.seen] = ftell(config_file);
 476                         store.seen++;
 477                 }
 478                 break;
 479         case SECTION_SEEN:
 480                 /*
 481                  * What we are looking for is in store.key (both
 482                  * section and var), and its section part is baselen
 483                  * long.  We found key (again, both section and var).
 484                  * We would want to know if this key is in the same
 485                  * section as what we are looking for.  We already
 486                  * know we are in the same section as what should
 487                  * hold store.key.
 488                  */
 489                 ep = strrchr(key, '.');
 490                 section_len = ep - key;
 491
 492                 if ((section_len != store.baselen) ||
 493                     memcmp(key, store.key, section_len+1)) {
 494                         store.state = SECTION_END_SEEN;
 495                         break;
 496                 }
 497
 498                 /*
 499                  * Do not increment matches: this is no match, but we
 500                  * just made sure we are in the desired section.
 501                  */
 502                 store.offset[store.seen] = ftell(config_file);
 503                 /* fallthru */
 504         case SECTION_END_SEEN:
 505         case START:
 506                 if (matches(key, value)) {
 507                         store.offset[store.seen] = ftell(config_file);
 508                         store.state = KEY_SEEN;
 509                         store.seen++;
 510                 } else {
 511                         if (strrchr(key, '.') - key == store.baselen &&
 512                               !strncmp(key, store.key, store.baselen)) {
 513                                         store.state = SECTION_SEEN;
 514                                         store.offset[store.seen] = ftell(config_file);
 515                         }
 516                 }
 517         }
 518         return 0;
 519 }
 520
 521 static int write_error()
 522 {
 523         fprintf(stderr, "Failed to write new configuration file\n");
 524
 525         /* Same error code as "failed to rename". */
 526         return 4;
 527 }
 528
 529 static int store_write_section(int fd, const char* key)
 530 {
 531         const char *dot = strchr(key, '.');
 532         int len1 = store.baselen, len2 = -1;
 533
 534         dot = strchr(key, '.');
 535         if (dot) {
 536                 int dotlen = dot - key;
 537                 if (dotlen < len1) {
 538                         len2 = len1 - dotlen - 1;
 539                         len1 = dotlen;
 540                 }
 541         }
 542
 543         if (write_in_full(fd, "[", 1) != 1 ||
 544             write_in_full(fd, key, len1) != len1)
 545                 return 0;
 546         if (len2 >= 0) {
 547                 if (write_in_full(fd, " \"", 2) != 2)
 548                         return 0;
 549                 while (--len2 >= 0) {
 550                         unsigned char c = *++dot;
 551                         if (c == '"')
 552                                 if (write_in_full(fd, "\\", 1) != 1)
 553                                         return 0;
 554                         if (write_in_full(fd, &c, 1) != 1)
 555                                 return 0;
 556                 }
 557                 if (write_in_full(fd, "\"", 1) != 1)
 558                         return 0;
 559         }
 560         if (write_in_full(fd, "]\n", 2) != 2)
 561                 return 0;
 562
 563         return 1;
 564 }
 565
 566 static int store_write_pair(int fd, const char* key, const char* value)
 567 {
 568         int i;
 569         int length = strlen(key+store.baselen+1);
 570         int quote = 0;
 571
 572         /* Check to see if the value needs to be quoted. */
 573         if (value[0] == ' ')
 574                 quote = 1;
 575         for (i = 0; value[i]; i++)
 576                 if (value[i] == ';' || value[i] == '#')
 577                         quote = 1;
 578         if (value[i-1] == ' ')
 579                 quote = 1;
 580
 581         if (write_in_full(fd, "\t", 1) != 1 ||
 582             write_in_full(fd, key+store.baselen+1, length) != length ||
 583             write_in_full(fd, " = ", 3) != 3)
 584                 return 0;
 585         if (quote && write_in_full(fd, "\"", 1) != 1)
 586                 return 0;
 587         for (i = 0; value[i]; i++)
 588                 switch (value[i]) {
 589                 case '\n':
 590                         if (write_in_full(fd, "\\n", 2) != 2)
 591                                 return 0;
 592                         break;
 593                 case '\t':
 594                         if (write_in_full(fd, "\\t", 2) != 2)
 595                                 return 0;
 596                         break;
 597                 case '"':
 598                 case '\\':
 599                         if (write_in_full(fd, "\\", 1) != 1)
 600                                 return 0;
 601                 default:
 602                         if (write_in_full(fd, value+i, 1) != 1)
 603                                 return 0;
 604                         break;
 605                 }
 606         if (quote && write_in_full(fd, "\"", 1) != 1)
 607                 return 0;
 608         if (write_in_full(fd, "\n", 1) != 1)
 609                 return 0;
 610         return 1;
 611 }
 612
 613 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 614         size_t offset_, int* found_bracket)
 615 {
 616         size_t equal_offset = size, bracket_offset = size;
 617         ssize_t offset;
 618
 619         for (offset = offset_-2; offset > 0
 620                         && contents[offset] != '\n'; offset--)
 621                 switch (contents[offset]) {
 622                         case '=': equal_offset = offset; break;
 623                         case ']': bracket_offset = offset; break;
 624                 }
 625         if (bracket_offset < equal_offset) {
 626                 *found_bracket = 1;
 627                 offset = bracket_offset+1;
 628         } else
 629                 offset++;
 630
 631         return offset;
 632 }
 633
 634 int git_config_set(const char* key, const char* value)
 635 {
 636         return git_config_set_multivar(key, value, NULL, 0);
 637 }
 638
 639 /*
 640  * If value==NULL, unset in (remove from) config,
 641  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 642  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 643  *     else all matching key/values (regardless how many) are removed,
 644  *     before the new pair is written.
 645  *
 646  * Returns 0 on success.
 647  *
 648  * This function does this:
 649  *
 650  * - it locks the config file by creating ".git/config.lock"
 651  *
 652  * - it then parses the config using store_aux() as validator to find
 653  *   the position on the key/value pair to replace. If it is to be unset,
 654  *   it must be found exactly once.
 655  *
 656  * - the config file is mmap()ed and the part before the match (if any) is
 657  *   written to the lock file, then the changed part and the rest.
 658  *
 659  * - the config file is removed and the lock file rename()d to it.
 660  *
 661  */
 662 int git_config_set_multivar(const char* key, const char* value,
 663         const char* value_regex, int multi_replace)
 664 {
 665         int i, dot;
 666         int fd = -1, in_fd;
 667         int ret;
 668         char* config_filename;
 669         char* lock_file;
 670         const char* last_dot = strrchr(key, '.');
 671
 672         config_filename = getenv(CONFIG_ENVIRONMENT);
 673         if (!config_filename) {
 674                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 675                 if (!config_filename)
 676                         config_filename  = git_path("config");
 677         }
 678         config_filename = xstrdup(config_filename);
 679         lock_file = xstrdup(mkpath("%s.lock", config_filename));
 680
 681         /*
 682          * Since "key" actually contains the section name and the real
 683          * key name separated by a dot, we have to know where the dot is.
 684          */
 685
 686         if (last_dot == NULL) {
 687                 fprintf(stderr, "key does not contain a section: %s\n", key);
 688                 ret = 2;
 689                 goto out_free;
 690         }
 691         store.baselen = last_dot - key;
 692
 693         store.multi_replace = multi_replace;
 694
 695         /*
 696          * Validate the key and while at it, lower case it for matching.
 697          */
 698         store.key = xmalloc(strlen(key) + 1);
 699         dot = 0;
 700         for (i = 0; key[i]; i++) {
 701                 unsigned char c = key[i];
 702                 if (c == '.')
 703                         dot = 1;
 704                 /* Leave the extended basename untouched.. */
 705                 if (!dot || i > store.baselen) {
 706                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 707                                 fprintf(stderr, "invalid key: %s\n", key);
 708                                 free(store.key);
 709                                 ret = 1;
 710                                 goto out_free;
 711                         }
 712                         c = tolower(c);
 713                 } else if (c == '\n') {
 714                         fprintf(stderr, "invalid key (newline): %s\n", key);
 715                         free(store.key);
 716                         ret = 1;
 717                         goto out_free;
 718                 }
 719                 store.key[i] = c;
 720         }
 721         store.key[i] = 0;
 722
 723         /*
 724          * The lock_file serves a purpose in addition to locking: the new
 725          * contents of .git/config will be written into it.
 726          */
 727         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 728         if (fd < 0 || adjust_shared_perm(lock_file)) {
 729                 fprintf(stderr, "could not lock config file\n");
 730                 free(store.key);
 731                 ret = -1;
 732                 goto out_free;
 733         }
 734
 735         /*
 736          * If .git/config does not exist yet, write a minimal version.
 737          */
 738         in_fd = open(config_filename, O_RDONLY);
 739         if ( in_fd < 0 ) {
 740                 free(store.key);
 741
 742                 if ( ENOENT != errno ) {
 743                         error("opening %s: %s", config_filename,
 744                               strerror(errno));
 745                         ret = 3; /* same as "invalid config file" */
 746                         goto out_free;
 747                 }
 748                 /* if nothing to unset, error out */
 749                 if (value == NULL) {
 750                         ret = 5;
 751                         goto out_free;
 752                 }
 753
 754                 store.key = (char*)key;
 755                 if (!store_write_section(fd, key) ||
 756                     !store_write_pair(fd, key, value))
 757                         goto write_err_out;
 758         } else {
 759                 struct stat st;
 760                 char* contents;
 761                 size_t contents_sz, copy_begin, copy_end;
 762                 int i, new_line = 0;
 763
 764                 if (value_regex == NULL)
 765                         store.value_regex = NULL;
 766                 else {
 767                         if (value_regex[0] == '!') {
 768                                 store.do_not_match = 1;
 769                                 value_regex++;
 770                         } else
 771                                 store.do_not_match = 0;
 772
 773                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 774                         if (regcomp(store.value_regex, value_regex,
 775                                         REG_EXTENDED)) {
 776                                 fprintf(stderr, "Invalid pattern: %s\n",
 777                                         value_regex);
 778                                 free(store.value_regex);
 779                                 ret = 6;
 780                                 goto out_free;
 781                         }
 782                 }
 783
 784                 store.offset[0] = 0;
 785                 store.state = START;
 786                 store.seen = 0;
 787
 788                 /*
 789                  * After this, store.offset will contain the *end* offset
 790                  * of the last match, or remain at 0 if no match was found.
 791                  * As a side effect, we make sure to transform only a valid
 792                  * existing config file.
 793                  */
 794                 if (git_config_from_file(store_aux, config_filename)) {
 795                         fprintf(stderr, "invalid config file\n");
 796                         free(store.key);
 797                         if (store.value_regex != NULL) {
 798                                 regfree(store.value_regex);
 799                                 free(store.value_regex);
 800                         }
 801                         ret = 3;
 802                         goto out_free;
 803                 }
 804
 805                 free(store.key);
 806                 if (store.value_regex != NULL) {
 807                         regfree(store.value_regex);
 808                         free(store.value_regex);
 809                 }
 810
 811                 /* if nothing to unset, or too many matches, error out */
 812                 if ((store.seen == 0 && value == NULL) ||
 813                                 (store.seen > 1 && multi_replace == 0)) {
 814                         ret = 5;
 815                         goto out_free;
 816                 }
 817
 818                 fstat(in_fd, &st);
 819                 contents_sz = xsize_t(st.st_size);
 820                 contents = xmmap(NULL, contents_sz, PROT_READ,
 821                         MAP_PRIVATE, in_fd, 0);
 822                 close(in_fd);
 823
 824                 if (store.seen == 0)
 825                         store.seen = 1;
 826
 827                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 828                         if (store.offset[i] == 0) {
 829                                 store.offset[i] = copy_end = contents_sz;
 830                         } else if (store.state != KEY_SEEN) {
 831                                 copy_end = store.offset[i];
 832                         } else
 833                                 copy_end = find_beginning_of_line(
 834                                         contents, contents_sz,
 835                                         store.offset[i]-2, &new_line);
 836
 837                         /* write the first part of the config */
 838                         if (copy_end > copy_begin) {
 839                                 if (write_in_full(fd, contents + copy_begin,
 840                                                   copy_end - copy_begin) <
 841                                     copy_end - copy_begin)
 842                                         goto write_err_out;
 843                                 if (new_line &&
 844                                     write_in_full(fd, "\n", 1) != 1)
 845                                         goto write_err_out;
 846                         }
 847                         copy_begin = store.offset[i];
 848                 }
 849
 850                 /* write the pair (value == NULL means unset) */
 851                 if (value != NULL) {
 852                         if (store.state == START) {
 853                                 if (!store_write_section(fd, key))
 854                                         goto write_err_out;
 855                         }
 856                         if (!store_write_pair(fd, key, value))
 857                                 goto write_err_out;
 858                 }
 859
 860                 /* write the rest of the config */
 861                 if (copy_begin < contents_sz)
 862                         if (write_in_full(fd, contents + copy_begin,
 863                                           contents_sz - copy_begin) <
 864                             contents_sz - copy_begin)
 865                                 goto write_err_out;
 866
 867                 munmap(contents, contents_sz);
 868                 unlink(config_filename);
 869         }
 870
 871         close(fd);
 872         fd = -1;
 873         if (rename(lock_file, config_filename) < 0) {
 874                 fprintf(stderr, "Could not rename the lock file?\n");
 875                 ret = 4;
 876                 goto out_free;
 877         }
 878
 879         ret = 0;
 880
 881 out_free:
 882         if (0 <= fd)
 883                 close(fd);
 884         free(config_filename);
 885         if (lock_file) {
 886                 unlink(lock_file);
 887                 free(lock_file);
 888         }
 889         return ret;
 890
 891 write_err_out:
 892         ret = write_error();
 893         goto out_free;
 894
 895 }
 896
 897 static int section_name_match (const char *buf, const char *name)
 898 {
 899         int i = 0, j = 0, dot = 0;
 900         for (; buf[i] && buf[i] != ']'; i++) {
 901                 if (!dot && isspace(buf[i])) {
 902                         dot = 1;
 903                         if (name[j++] != '.')
 904                                 break;
 905                         for (i++; isspace(buf[i]); i++)
 906                                 ; /* do nothing */
 907                         if (buf[i] != '"')
 908                                 break;
 909                         continue;
 910                 }
 911                 if (buf[i] == '\\' && dot)
 912                         i++;
 913                 else if (buf[i] == '"' && dot) {
 914                         for (i++; isspace(buf[i]); i++)
 915                                 ; /* do_nothing */
 916                         break;
 917                 }
 918                 if (buf[i] != name[j++])
 919                         break;
 920         }
 921         return (buf[i] == ']' && name[j] == 0);
 922 }
 923
 924 /* if new_name == NULL, the section is removed instead */
 925 int git_config_rename_section(const char *old_name, const char *new_name)
 926 {
 927         int ret = 0, remove = 0;
 928         char *config_filename;
 929         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 930         int out_fd;
 931         char buf[1024];
 932
 933         config_filename = getenv(CONFIG_ENVIRONMENT);
 934         if (!config_filename) {
 935                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 936                 if (!config_filename)
 937                         config_filename  = git_path("config");
 938         }
 939         config_filename = xstrdup(config_filename);
 940         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 941         if (out_fd < 0) {
 942                 ret = error("Could not lock config file!");
 943                 goto out;
 944         }
 945
 946         if (!(config_file = fopen(config_filename, "rb"))) {
 947                 /* no config file means nothing to rename, no error */
 948                 goto unlock_and_out;
 949         }
 950
 951         while (fgets(buf, sizeof(buf), config_file)) {
 952                 int i;
 953                 int length;
 954                 for (i = 0; buf[i] && isspace(buf[i]); i++)
 955                         ; /* do nothing */
 956                 if (buf[i] == '[') {
 957                         /* it's a section */
 958                         if (section_name_match (&buf[i+1], old_name)) {
 959                                 ret++;
 960                                 if (new_name == NULL) {
 961                                         remove = 1;
 962                                         continue;
 963                                 }
 964                                 store.baselen = strlen(new_name);
 965                                 if (!store_write_section(out_fd, new_name)) {
 966                                         ret = write_error();
 967                                         goto out;
 968                                 }
 969                                 continue;
 970                         }
 971                         remove = 0;
 972                 }
 973                 if (remove)
 974                         continue;
 975                 length = strlen(buf);
 976                 if (write_in_full(out_fd, buf, length) != length) {
 977                         ret = write_error();
 978                         goto out;
 979                 }
 980         }
 981         fclose(config_file);
 982  unlock_and_out:
 983         if (close(out_fd) || commit_lock_file(lock) < 0)
 984                         ret = error("Cannot commit config file!");
 985  out:
 986         free(config_filename);
 987         return ret;
 988 }
 989