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 zlib_compression_seen;
  17
  18 extern int getpagesize();
  19
  20 static int get_next_char(void)
  21 {
  22         int c;
  23         FILE *f;
  24
  25         c = '\n';
  26         if ((f = config_file) != NULL) {
  27                 c = fgetc(f);
  28                 if (c == '\r') {
  29                         /* DOS like systems */
  30                         c = fgetc(f);
  31                         if (c != '\n') {
  32                                 ungetc(c, f);
  33                                 c = '\r';
  34                         }
  35                 }
  36                 if (c == '\n')
  37                         config_linenr++;
  38                 if (c == EOF) {
  39                         config_file = NULL;
  40                         c = '\n';
  41                 }
  42         }
  43         return c;
  44 }
  45
  46 static char *parse_value(void)
  47 {
  48         static char value[1024];
  49         int quote = 0, comment = 0, len = 0, space = 0;
  50
  51         for (;;) {
  52                 int c = get_next_char();
  53                 if (len >= sizeof(value))
  54                         return NULL;
  55                 if (c == '\n') {
  56                         if (quote)
  57                                 return NULL;
  58                         value[len] = 0;
  59                         return value;
  60                 }
  61                 if (comment)
  62                         continue;
  63                 if (isspace(c) && !quote) {
  64                         space = 1;
  65                         continue;
  66                 }
  67                 if (!quote) {
  68                         if (c == ';' || c == '#') {
  69                                 comment = 1;
  70                                 continue;
  71                         }
  72                 }
  73                 if (space) {
  74                         if (len)
  75                                 value[len++] = ' ';
  76                         space = 0;
  77                 }
  78                 if (c == '\\') {
  79                         c = get_next_char();
  80                         switch (c) {
  81                         case '\n':
  82                                 continue;
  83                         case 't':
  84                                 c = '\t';
  85                                 break;
  86                         case 'b':
  87                                 c = '\b';
  88                                 break;
  89                         case 'n':
  90                                 c = '\n';
  91                                 break;
  92                         /* Some characters escape as themselves */
  93                         case '\\': case '"':
  94                                 break;
  95                         /* Reject unknown escape sequences */
  96                         default:
  97                                 return NULL;
  98                         }
  99                         value[len++] = c;
 100                         continue;
 101                 }
 102                 if (c == '"') {
 103                         quote = 1-quote;
 104                         continue;
 105                 }
 106                 value[len++] = c;
 107         }
 108 }
 109
 110 static inline int iskeychar(int c)
 111 {
 112         return isalnum(c) || c == '-';
 113 }
 114
 115 static int get_value(config_fn_t fn, char *name, unsigned int len)
 116 {
 117         int c;
 118         char *value;
 119
 120         /* Get the full name */
 121         for (;;) {
 122                 c = get_next_char();
 123                 if (c == EOF)
 124                         break;
 125                 if (!iskeychar(c))
 126                         break;
 127                 name[len++] = tolower(c);
 128                 if (len >= MAXNAME)
 129                         return -1;
 130         }
 131         name[len] = 0;
 132         while (c == ' ' || c == '\t')
 133                 c = get_next_char();
 134
 135         value = NULL;
 136         if (c != '\n') {
 137                 if (c != '=')
 138                         return -1;
 139                 value = parse_value();
 140                 if (!value)
 141                         return -1;
 142         }
 143         return fn(name, value);
 144 }
 145
 146 static int get_extended_base_var(char *name, int baselen, int c)
 147 {
 148         do {
 149                 if (c == '\n')
 150                         return -1;
 151                 c = get_next_char();
 152         } while (isspace(c));
 153
 154         /* We require the format to be '[base "extension"]' */
 155         if (c != '"')
 156                 return -1;
 157         name[baselen++] = '.';
 158
 159         for (;;) {
 160                 int c = get_next_char();
 161                 if (c == '\n')
 162                         return -1;
 163                 if (c == '"')
 164                         break;
 165                 if (c == '\\') {
 166                         c = get_next_char();
 167                         if (c == '\n')
 168                                 return -1;
 169                 }
 170                 name[baselen++] = c;
 171                 if (baselen > MAXNAME / 2)
 172                         return -1;
 173         }
 174
 175         /* Final ']' */
 176         if (get_next_char() != ']')
 177                 return -1;
 178         return baselen;
 179 }
 180
 181 static int get_base_var(char *name)
 182 {
 183         int baselen = 0;
 184
 185         for (;;) {
 186                 int c = get_next_char();
 187                 if (c == EOF)
 188                         return -1;
 189                 if (c == ']')
 190                         return baselen;
 191                 if (isspace(c))
 192                         return get_extended_base_var(name, baselen, c);
 193                 if (!iskeychar(c) && c != '.')
 194                         return -1;
 195                 if (baselen > MAXNAME / 2)
 196                         return -1;
 197                 name[baselen++] = tolower(c);
 198         }
 199 }
 200
 201 static int git_parse_file(config_fn_t fn)
 202 {
 203         int comment = 0;
 204         int baselen = 0;
 205         static char var[MAXNAME];
 206
 207         for (;;) {
 208                 int c = get_next_char();
 209                 if (c == '\n') {
 210                         /* EOF? */
 211                         if (!config_file)
 212                                 return 0;
 213                         comment = 0;
 214                         continue;
 215                 }
 216                 if (comment || isspace(c))
 217                         continue;
 218                 if (c == '#' || c == ';') {
 219                         comment = 1;
 220                         continue;
 221                 }
 222                 if (c == '[') {
 223                         baselen = get_base_var(var);
 224                         if (baselen <= 0)
 225                                 break;
 226                         var[baselen++] = '.';
 227                         var[baselen] = 0;
 228                         continue;
 229                 }
 230                 if (!isalpha(c))
 231                         break;
 232                 var[baselen] = tolower(c);
 233                 if (get_value(fn, var, baselen+1) < 0)
 234                         break;
 235         }
 236         die("bad config file line %d in %s", config_linenr, config_file_name);
 237 }
 238
 239 static unsigned long get_unit_factor(const char *end)
 240 {
 241         if (!*end)
 242                 return 1;
 243         else if (!strcasecmp(end, "k"))
 244                 return 1024;
 245         else if (!strcasecmp(end, "m"))
 246                 return 1024 * 1024;
 247         else if (!strcasecmp(end, "g"))
 248                 return 1024 * 1024 * 1024;
 249         die("unknown unit: '%s'", end);
 250 }
 251
 252 int git_parse_long(const char *value, long *ret)
 253 {
 254         if (value && *value) {
 255                 char *end;
 256                 long val = strtol(value, &end, 0);
 257                 *ret = val * get_unit_factor(end);
 258                 return 1;
 259         }
 260         return 0;
 261 }
 262
 263 int git_parse_ulong(const char *value, unsigned long *ret)
 264 {
 265         if (value && *value) {
 266                 char *end;
 267                 unsigned long val = strtoul(value, &end, 0);
 268                 *ret = val * get_unit_factor(end);
 269                 return 1;
 270         }
 271         return 0;
 272 }
 273
 274 int git_config_int(const char *name, const char *value)
 275 {
 276         long ret;
 277         if (!git_parse_long(value, &ret))
 278                 die("bad config value for '%s' in %s", name, config_file_name);
 279         return ret;
 280 }
 281
 282 unsigned long git_config_ulong(const char *name, const char *value)
 283 {
 284         unsigned long ret;
 285         if (!git_parse_ulong(value, &ret))
 286                 die("bad config value for '%s' in %s", name, config_file_name);
 287         return ret;
 288 }
 289
 290 int git_config_bool(const char *name, const char *value)
 291 {
 292         if (!value)
 293                 return 1;
 294         if (!*value)
 295                 return 0;
 296         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 297                 return 1;
 298         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 299                 return 0;
 300         return git_config_int(name, value) != 0;
 301 }
 302
 303 int git_default_config(const char *var, const char *value)
 304 {
 305         /* This needs a better name */
 306         if (!strcmp(var, "core.filemode")) {
 307                 trust_executable_bit = git_config_bool(var, value);
 308                 return 0;
 309         }
 310
 311         if (!strcmp(var, "core.quotepath")) {
 312                 quote_path_fully = git_config_bool(var, value);
 313                 return 0;
 314         }
 315
 316         if (!strcmp(var, "core.symlinks")) {
 317                 has_symlinks = git_config_bool(var, value);
 318                 return 0;
 319         }
 320
 321         if (!strcmp(var, "core.bare")) {
 322                 is_bare_repository_cfg = git_config_bool(var, value);
 323                 return 0;
 324         }
 325
 326         if (!strcmp(var, "core.ignorestat")) {
 327                 assume_unchanged = git_config_bool(var, value);
 328                 return 0;
 329         }
 330
 331         if (!strcmp(var, "core.prefersymlinkrefs")) {
 332                 prefer_symlink_refs = git_config_bool(var, value);
 333                 return 0;
 334         }
 335
 336         if (!strcmp(var, "core.logallrefupdates")) {
 337                 log_all_ref_updates = git_config_bool(var, value);
 338                 return 0;
 339         }
 340
 341         if (!strcmp(var, "core.warnambiguousrefs")) {
 342                 warn_ambiguous_refs = git_config_bool(var, value);
 343                 return 0;
 344         }
 345
 346         if (!strcmp(var, "core.loosecompression")) {
 347                 int level = git_config_int(var, value);
 348                 if (level == -1)
 349                         level = Z_DEFAULT_COMPRESSION;
 350                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 351                         die("bad zlib compression level %d", level);
 352                 zlib_compression_level = level;
 353                 zlib_compression_seen = 1;
 354                 return 0;
 355         }
 356
 357         if (!strcmp(var, "core.compression")) {
 358                 int level = git_config_int(var, value);
 359                 if (level == -1)
 360                         level = Z_DEFAULT_COMPRESSION;
 361                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 362                         die("bad zlib compression level %d", level);
 363                 core_compression_level = level;
 364                 core_compression_seen = 1;
 365                 if (!zlib_compression_seen)
 366                         zlib_compression_level = level;
 367                 return 0;
 368         }
 369
 370         if (!strcmp(var, "core.packedgitwindowsize")) {
 371                 int pgsz_x2 = getpagesize() * 2;
 372                 packed_git_window_size = git_config_int(var, value);
 373
 374                 /* This value must be multiple of (pagesize * 2) */
 375                 packed_git_window_size /= pgsz_x2;
 376                 if (packed_git_window_size < 1)
 377                         packed_git_window_size = 1;
 378                 packed_git_window_size *= pgsz_x2;
 379                 return 0;
 380         }
 381
 382         if (!strcmp(var, "core.packedgitlimit")) {
 383                 packed_git_limit = git_config_int(var, value);
 384                 return 0;
 385         }
 386
 387         if (!strcmp(var, "core.deltabasecachelimit")) {
 388                 delta_base_cache_limit = git_config_int(var, value);
 389                 return 0;
 390         }
 391
 392         if (!strcmp(var, "core.autocrlf")) {
 393                 if (value && !strcasecmp(value, "input")) {
 394                         auto_crlf = -1;
 395                         return 0;
 396                 }
 397                 auto_crlf = git_config_bool(var, value);
 398                 return 0;
 399         }
 400
 401         if (!strcmp(var, "user.name")) {
 402                 strlcpy(git_default_name, value, sizeof(git_default_name));
 403                 return 0;
 404         }
 405
 406         if (!strcmp(var, "user.email")) {
 407                 strlcpy(git_default_email, value, sizeof(git_default_email));
 408                 return 0;
 409         }
 410
 411         if (!strcmp(var, "i18n.commitencoding")) {
 412                 git_commit_encoding = xstrdup(value);
 413                 return 0;
 414         }
 415
 416         if (!strcmp(var, "i18n.logoutputencoding")) {
 417                 git_log_output_encoding = xstrdup(value);
 418                 return 0;
 419         }
 420
 421
 422         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 423                 pager_use_color = git_config_bool(var,value);
 424                 return 0;
 425         }
 426
 427         if (!strcmp(var, "core.pager")) {
 428                 pager_program = xstrdup(value);
 429                 return 0;
 430         }
 431
 432         if (!strcmp(var, "core.editor")) {
 433                 editor_program = xstrdup(value);
 434                 return 0;
 435         }
 436
 437         /* Add other config variables here and to Documentation/config.txt. */
 438         return 0;
 439 }
 440
 441 int git_config_from_file(config_fn_t fn, const char *filename)
 442 {
 443         int ret;
 444         FILE *f = fopen(filename, "r");
 445
 446         ret = 1;
 447         if (f) {
 448                 config_file = f;
 449                 config_file_name = filename;
 450                 config_linenr = 1;
 451                 ret = git_parse_file(fn);
 452                 fclose(f);
 453                 config_file_name = NULL;
 454         }
 455         return ret;
 456 }
 457
 458 const char *git_etc_gitconfig(void)
 459 {
 460         static const char *system_wide;
 461         if (!system_wide) {
 462                 system_wide = ETC_GITCONFIG;
 463                 /* interpret path relative to exec-dir */
 464                 if (system_wide[0] != '/' && system_wide[1] != ':') {
 465                         const char *exec_path = git_exec_path();
 466                         system_wide = prefix_path(exec_path, strlen(exec_path),
 467                                                 system_wide);
 468                 }
 469         }
 470         return system_wide;
 471 }
 472
 473 int git_config(config_fn_t fn)
 474 {
 475         int ret = 0;
 476         char *repo_config = NULL;
 477         const char *home = NULL, *filename;
 478
 479         /* $GIT_CONFIG makes git read _only_ the given config file,
 480          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 481          * global config file, the same way it would the per-repository
 482          * config file otherwise. */
 483         filename = getenv(CONFIG_ENVIRONMENT);
 484         if (!filename) {
 485                 if (!access(git_etc_gitconfig(), R_OK))
 486                         ret += git_config_from_file(fn, git_etc_gitconfig());
 487                 home = getenv("HOME");
 488                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 489                 if (!filename)
 490                         filename = repo_config = xstrdup(git_path("config"));
 491         }
 492
 493         if (home) {
 494                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 495                 if (!access(user_config, R_OK))
 496                         ret = git_config_from_file(fn, user_config);
 497                 free(user_config);
 498         }
 499
 500         ret += git_config_from_file(fn, filename);
 501         free(repo_config);
 502         return ret;
 503 }
 504
 505 /*
 506  * Find all the stuff for git_config_set() below.
 507  */
 508
 509 #define MAX_MATCHES 512
 510
 511 static struct {
 512         int baselen;
 513         char* key;
 514         int do_not_match;
 515         regex_t* value_regex;
 516         int multi_replace;
 517         size_t offset[MAX_MATCHES];
 518         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 519         int seen;
 520 } store;
 521
 522 static int matches(const char* key, const char* value)
 523 {
 524         return !strcmp(key, store.key) &&
 525                 (store.value_regex == NULL ||
 526                  (store.do_not_match ^
 527                   !regexec(store.value_regex, value, 0, NULL, 0)));
 528 }
 529
 530 static int store_aux(const char* key, const char* value)
 531 {
 532         const char *ep;
 533         size_t section_len;
 534
 535         switch (store.state) {
 536         case KEY_SEEN:
 537                 if (matches(key, value)) {
 538                         if (store.seen == 1 && store.multi_replace == 0) {
 539                                 fprintf(stderr,
 540                                         "Warning: %s has multiple values\n",
 541                                         key);
 542                         } else if (store.seen >= MAX_MATCHES) {
 543                                 fprintf(stderr, "Too many matches\n");
 544                                 return 1;
 545                         }
 546
 547                         store.offset[store.seen] = ftell(config_file);
 548                         store.seen++;
 549                 }
 550                 break;
 551         case SECTION_SEEN:
 552                 /*
 553                  * What we are looking for is in store.key (both
 554                  * section and var), and its section part is baselen
 555                  * long.  We found key (again, both section and var).
 556                  * We would want to know if this key is in the same
 557                  * section as what we are looking for.  We already
 558                  * know we are in the same section as what should
 559                  * hold store.key.
 560                  */
 561                 ep = strrchr(key, '.');
 562                 section_len = ep - key;
 563
 564                 if ((section_len != store.baselen) ||
 565                     memcmp(key, store.key, section_len+1)) {
 566                         store.state = SECTION_END_SEEN;
 567                         break;
 568                 }
 569
 570                 /*
 571                  * Do not increment matches: this is no match, but we
 572                  * just made sure we are in the desired section.
 573                  */
 574                 store.offset[store.seen] = ftell(config_file);
 575                 /* fallthru */
 576         case SECTION_END_SEEN:
 577         case START:
 578                 if (matches(key, value)) {
 579                         store.offset[store.seen] = ftell(config_file);
 580                         store.state = KEY_SEEN;
 581                         store.seen++;
 582                 } else {
 583                         if (strrchr(key, '.') - key == store.baselen &&
 584                               !strncmp(key, store.key, store.baselen)) {
 585                                         store.state = SECTION_SEEN;
 586                                         store.offset[store.seen] = ftell(config_file);
 587                         }
 588                 }
 589         }
 590         return 0;
 591 }
 592
 593 static int write_error(void)
 594 {
 595         fprintf(stderr, "Failed to write new configuration file\n");
 596
 597         /* Same error code as "failed to rename". */
 598         return 4;
 599 }
 600
 601 static int store_write_section(int fd, const char* key)
 602 {
 603         const char *dot = strchr(key, '.');
 604         int len1 = store.baselen, len2 = -1;
 605
 606         dot = strchr(key, '.');
 607         if (dot) {
 608                 int dotlen = dot - key;
 609                 if (dotlen < len1) {
 610                         len2 = len1 - dotlen - 1;
 611                         len1 = dotlen;
 612                 }
 613         }
 614
 615         if (write_in_full(fd, "[", 1) != 1 ||
 616             write_in_full(fd, key, len1) != len1)
 617                 return 0;
 618         if (len2 >= 0) {
 619                 if (write_in_full(fd, " \"", 2) != 2)
 620                         return 0;
 621                 while (--len2 >= 0) {
 622                         unsigned char c = *++dot;
 623                         if (c == '"')
 624                                 if (write_in_full(fd, "\\", 1) != 1)
 625                                         return 0;
 626                         if (write_in_full(fd, &c, 1) != 1)
 627                                 return 0;
 628                 }
 629                 if (write_in_full(fd, "\"", 1) != 1)
 630                         return 0;
 631         }
 632         if (write_in_full(fd, "]\n", 2) != 2)
 633                 return 0;
 634
 635         return 1;
 636 }
 637
 638 static int store_write_pair(int fd, const char* key, const char* value)
 639 {
 640         int i;
 641         int length = strlen(key+store.baselen+1);
 642         int quote = 0;
 643
 644         /* Check to see if the value needs to be quoted. */
 645         if (value[0] == ' ')
 646                 quote = 1;
 647         for (i = 0; value[i]; i++)
 648                 if (value[i] == ';' || value[i] == '#')
 649                         quote = 1;
 650         if (value[i-1] == ' ')
 651                 quote = 1;
 652
 653         if (write_in_full(fd, "\t", 1) != 1 ||
 654             write_in_full(fd, key+store.baselen+1, length) != length ||
 655             write_in_full(fd, " = ", 3) != 3)
 656                 return 0;
 657         if (quote && write_in_full(fd, "\"", 1) != 1)
 658                 return 0;
 659         for (i = 0; value[i]; i++)
 660                 switch (value[i]) {
 661                 case '\n':
 662                         if (write_in_full(fd, "\\n", 2) != 2)
 663                                 return 0;
 664                         break;
 665                 case '\t':
 666                         if (write_in_full(fd, "\\t", 2) != 2)
 667                                 return 0;
 668                         break;
 669                 case '"':
 670                 case '\\':
 671                         if (write_in_full(fd, "\\", 1) != 1)
 672                                 return 0;
 673                 default:
 674                         if (write_in_full(fd, value+i, 1) != 1)
 675                                 return 0;
 676                         break;
 677                 }
 678         if (quote && write_in_full(fd, "\"", 1) != 1)
 679                 return 0;
 680         if (write_in_full(fd, "\n", 1) != 1)
 681                 return 0;
 682         return 1;
 683 }
 684
 685 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 686         size_t offset_, int* found_bracket)
 687 {
 688         size_t equal_offset = size, bracket_offset = size;
 689         ssize_t offset;
 690
 691         for (offset = offset_-2; offset > 0
 692                         && contents[offset] != '\n'; offset--)
 693                 switch (contents[offset]) {
 694                         case '=': equal_offset = offset; break;
 695                         case ']': bracket_offset = offset; break;
 696                 }
 697         if (bracket_offset < equal_offset) {
 698                 *found_bracket = 1;
 699                 offset = bracket_offset+1;
 700         } else
 701                 offset++;
 702
 703         return offset;
 704 }
 705
 706 int git_config_set(const char* key, const char* value)
 707 {
 708         return git_config_set_multivar(key, value, NULL, 0);
 709 }
 710
 711 /*
 712  * If value==NULL, unset in (remove from) config,
 713  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 714  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 715  *     else all matching key/values (regardless how many) are removed,
 716  *     before the new pair is written.
 717  *
 718  * Returns 0 on success.
 719  *
 720  * This function does this:
 721  *
 722  * - it locks the config file by creating ".git/config.lock"
 723  *
 724  * - it then parses the config using store_aux() as validator to find
 725  *   the position on the key/value pair to replace. If it is to be unset,
 726  *   it must be found exactly once.
 727  *
 728  * - the config file is mmap()ed and the part before the match (if any) is
 729  *   written to the lock file, then the changed part and the rest.
 730  *
 731  * - the config file is removed and the lock file rename()d to it.
 732  *
 733  */
 734 int git_config_set_multivar(const char* key, const char* value,
 735         const char* value_regex, int multi_replace)
 736 {
 737         int i, dot;
 738         int fd = -1, in_fd;
 739         int ret;
 740         char* config_filename;
 741         struct lock_file *lock = NULL;
 742         const char* last_dot = strrchr(key, '.');
 743
 744         config_filename = getenv(CONFIG_ENVIRONMENT);
 745         if (!config_filename) {
 746                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 747                 if (!config_filename)
 748                         config_filename  = git_path("config");
 749         }
 750         config_filename = xstrdup(config_filename);
 751
 752         /*
 753          * Since "key" actually contains the section name and the real
 754          * key name separated by a dot, we have to know where the dot is.
 755          */
 756
 757         if (last_dot == NULL) {
 758                 fprintf(stderr, "key does not contain a section: %s\n", key);
 759                 ret = 2;
 760                 goto out_free;
 761         }
 762         store.baselen = last_dot - key;
 763
 764         store.multi_replace = multi_replace;
 765
 766         /*
 767          * Validate the key and while at it, lower case it for matching.
 768          */
 769         store.key = xmalloc(strlen(key) + 1);
 770         dot = 0;
 771         for (i = 0; key[i]; i++) {
 772                 unsigned char c = key[i];
 773                 if (c == '.')
 774                         dot = 1;
 775                 /* Leave the extended basename untouched.. */
 776                 if (!dot || i > store.baselen) {
 777                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 778                                 fprintf(stderr, "invalid key: %s\n", key);
 779                                 free(store.key);
 780                                 ret = 1;
 781                                 goto out_free;
 782                         }
 783                         c = tolower(c);
 784                 } else if (c == '\n') {
 785                         fprintf(stderr, "invalid key (newline): %s\n", key);
 786                         free(store.key);
 787                         ret = 1;
 788                         goto out_free;
 789                 }
 790                 store.key[i] = c;
 791         }
 792         store.key[i] = 0;
 793
 794         /*
 795          * The lock serves a purpose in addition to locking: the new
 796          * contents of .git/config will be written into it.
 797          */
 798         lock = xcalloc(sizeof(struct lock_file), 1);
 799         fd = hold_lock_file_for_update(lock, config_filename, 0);
 800         if (fd < 0) {
 801                 fprintf(stderr, "could not lock config file\n");
 802                 free(store.key);
 803                 ret = -1;
 804                 goto out_free;
 805         }
 806
 807         /*
 808          * If .git/config does not exist yet, write a minimal version.
 809          */
 810         in_fd = open(config_filename, O_RDONLY);
 811         if ( in_fd < 0 ) {
 812                 free(store.key);
 813
 814                 if ( ENOENT != errno ) {
 815                         error("opening %s: %s", config_filename,
 816                               strerror(errno));
 817                         ret = 3; /* same as "invalid config file" */
 818                         goto out_free;
 819                 }
 820                 /* if nothing to unset, error out */
 821                 if (value == NULL) {
 822                         ret = 5;
 823                         goto out_free;
 824                 }
 825
 826                 store.key = (char*)key;
 827                 if (!store_write_section(fd, key) ||
 828                     !store_write_pair(fd, key, value))
 829                         goto write_err_out;
 830         } else {
 831                 struct stat st;
 832                 char* contents;
 833                 size_t contents_sz, copy_begin, copy_end;
 834                 int i, new_line = 0;
 835
 836                 if (value_regex == NULL)
 837                         store.value_regex = NULL;
 838                 else {
 839                         if (value_regex[0] == '!') {
 840                                 store.do_not_match = 1;
 841                                 value_regex++;
 842                         } else
 843                                 store.do_not_match = 0;
 844
 845                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 846                         if (regcomp(store.value_regex, value_regex,
 847                                         REG_EXTENDED)) {
 848                                 fprintf(stderr, "Invalid pattern: %s\n",
 849                                         value_regex);
 850                                 free(store.value_regex);
 851                                 ret = 6;
 852                                 goto out_free;
 853                         }
 854                 }
 855
 856                 store.offset[0] = 0;
 857                 store.state = START;
 858                 store.seen = 0;
 859
 860                 /*
 861                  * After this, store.offset will contain the *end* offset
 862                  * of the last match, or remain at 0 if no match was found.
 863                  * As a side effect, we make sure to transform only a valid
 864                  * existing config file.
 865                  */
 866                 if (git_config_from_file(store_aux, config_filename)) {
 867                         fprintf(stderr, "invalid config file\n");
 868                         free(store.key);
 869                         if (store.value_regex != NULL) {
 870                                 regfree(store.value_regex);
 871                                 free(store.value_regex);
 872                         }
 873                         ret = 3;
 874                         goto out_free;
 875                 }
 876
 877                 free(store.key);
 878                 if (store.value_regex != NULL) {
 879                         regfree(store.value_regex);
 880                         free(store.value_regex);
 881                 }
 882
 883                 /* if nothing to unset, or too many matches, error out */
 884                 if ((store.seen == 0 && value == NULL) ||
 885                                 (store.seen > 1 && multi_replace == 0)) {
 886                         ret = 5;
 887                         goto out_free;
 888                 }
 889
 890                 fstat(in_fd, &st);
 891                 contents_sz = xsize_t(st.st_size);
 892                 contents = xmmap(NULL, contents_sz, PROT_READ,
 893                         MAP_PRIVATE, in_fd, 0);
 894                 close(in_fd);
 895
 896                 if (store.seen == 0)
 897                         store.seen = 1;
 898
 899                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 900                         if (store.offset[i] == 0) {
 901                                 store.offset[i] = copy_end = contents_sz;
 902                         } else if (store.state != KEY_SEEN) {
 903                                 copy_end = store.offset[i];
 904                         } else
 905                                 copy_end = find_beginning_of_line(
 906                                         contents, contents_sz,
 907                                         store.offset[i]-2, &new_line);
 908
 909                         /* write the first part of the config */
 910                         if (copy_end > copy_begin) {
 911                                 if (write_in_full(fd, contents + copy_begin,
 912                                                   copy_end - copy_begin) <
 913                                     copy_end - copy_begin)
 914                                         goto write_err_out;
 915                                 if (new_line &&
 916                                     write_in_full(fd, "\n", 1) != 1)
 917                                         goto write_err_out;
 918                         }
 919                         copy_begin = store.offset[i];
 920                 }
 921
 922                 /* write the pair (value == NULL means unset) */
 923                 if (value != NULL) {
 924                         if (store.state == START) {
 925                                 if (!store_write_section(fd, key))
 926                                         goto write_err_out;
 927                         }
 928                         if (!store_write_pair(fd, key, value))
 929                                 goto write_err_out;
 930                 }
 931
 932                 /* write the rest of the config */
 933                 if (copy_begin < contents_sz)
 934                         if (write_in_full(fd, contents + copy_begin,
 935                                           contents_sz - copy_begin) <
 936                             contents_sz - copy_begin)
 937                                 goto write_err_out;
 938
 939                 munmap(contents, contents_sz);
 940         }
 941
 942         if (close(fd) || commit_lock_file(lock) < 0) {
 943                 fprintf(stderr, "Cannot commit config file!\n");
 944                 fd =
 945                 ret = 4;
 946                 goto out_free;
 947         }
 948
 949         /* fd is closed, so don't try to close it below. */
 950         fd = -1;
 951         /*
 952          * lock is committed, so don't try to roll it back below.
 953          * NOTE: Since lockfile.c keeps a linked list of all created
 954          * lock_file structures, it isn't safe to free(lock).  It's
 955          * better to just leave it hanging around.
 956          */
 957         lock = NULL;
 958         ret = 0;
 959
 960 out_free:
 961         if (0 <= fd)
 962                 close(fd);
 963         if (lock)
 964                 rollback_lock_file(lock);
 965         free(config_filename);
 966         return ret;
 967
 968 write_err_out:
 969         ret = write_error();
 970         goto out_free;
 971
 972 }
 973
 974 static int section_name_match (const char *buf, const char *name)
 975 {
 976         int i = 0, j = 0, dot = 0;
 977         for (; buf[i] && buf[i] != ']'; i++) {
 978                 if (!dot && isspace(buf[i])) {
 979                         dot = 1;
 980                         if (name[j++] != '.')
 981                                 break;
 982                         for (i++; isspace(buf[i]); i++)
 983                                 ; /* do nothing */
 984                         if (buf[i] != '"')
 985                                 break;
 986                         continue;
 987                 }
 988                 if (buf[i] == '\\' && dot)
 989                         i++;
 990                 else if (buf[i] == '"' && dot) {
 991                         for (i++; isspace(buf[i]); i++)
 992                                 ; /* do_nothing */
 993                         break;
 994                 }
 995                 if (buf[i] != name[j++])
 996                         break;
 997         }
 998         return (buf[i] == ']' && name[j] == 0);
 999 }
1000
1001 /* if new_name == NULL, the section is removed instead */
1002 int git_config_rename_section(const char *old_name, const char *new_name)
1003 {
1004         int ret = 0, remove = 0;
1005         char *config_filename;
1006         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1007         int out_fd;
1008         char buf[1024];
1009
1010         config_filename = getenv(CONFIG_ENVIRONMENT);
1011         if (!config_filename) {
1012                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1013                 if (!config_filename)
1014                         config_filename  = git_path("config");
1015         }
1016         config_filename = xstrdup(config_filename);
1017         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1018         if (out_fd < 0) {
1019                 ret = error("Could not lock config file!");
1020                 goto out;
1021         }
1022
1023         if (!(config_file = fopen(config_filename, "rb"))) {
1024                 /* no config file means nothing to rename, no error */
1025                 goto unlock_and_out;
1026         }
1027
1028         while (fgets(buf, sizeof(buf), config_file)) {
1029                 int i;
1030                 int length;
1031                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1032                         ; /* do nothing */
1033                 if (buf[i] == '[') {
1034                         /* it's a section */
1035                         if (section_name_match (&buf[i+1], old_name)) {
1036                                 ret++;
1037                                 if (new_name == NULL) {
1038                                         remove = 1;
1039                                         continue;
1040                                 }
1041                                 store.baselen = strlen(new_name);
1042                                 if (!store_write_section(out_fd, new_name)) {
1043                                         ret = write_error();
1044                                         goto out;
1045                                 }
1046                                 continue;
1047                         }
1048                         remove = 0;
1049                 }
1050                 if (remove)
1051                         continue;
1052                 length = strlen(buf);
1053                 if (write_in_full(out_fd, buf, length) != length) {
1054                         ret = write_error();
1055                         goto out;
1056                 }
1057         }
1058         fclose(config_file);
1059  unlock_and_out:
1060         if (close(out_fd) || commit_lock_file(lock) < 0)
1061                         ret = error("Cannot commit config file!");
1062  out:
1063         free(config_filename);
1064         return ret;
1065 }