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 static struct whitespace_rule {
 250         const char *rule_name;
 251         unsigned rule_bits;
 252 } whitespace_rule_names[] = {
 253         { "trailing-space", WS_TRAILING_SPACE },
 254         { "space-before-tab", WS_SPACE_BEFORE_TAB },
 255 };
 256
 257 static unsigned parse_whitespace_rule(const char *string)
 258 {
 259         unsigned rule = WS_DEFAULT_RULE;
 260
 261         while (string) {
 262                 int i;
 263                 size_t len;
 264                 const char *ep;
 265                 int negated = 0;
 266
 267                 string = string + strspn(string, ", \t\n\r");
 268                 ep = strchr(string, ',');
 269                 if (!ep)
 270                         len = strlen(string);
 271                 else
 272                         len = ep - string;
 273
 274                 if (*string == '-') {
 275                         negated = 1;
 276                         string++;
 277                         len--;
 278                 }
 279                 if (!len)
 280                         break;
 281                 for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++) {
 282                         if (strncmp(whitespace_rule_names[i].rule_name,
 283                                     string, len))
 284                                 continue;
 285                         if (negated)
 286                                 rule &= ~whitespace_rule_names[i].rule_bits;
 287                         else
 288                                 rule |= whitespace_rule_names[i].rule_bits;
 289                         break;
 290                 }
 291                 string = ep;
 292         }
 293         return rule;
 294 }
 295
 296 int git_parse_long(const char *value, long *ret)
 297 {
 298         if (value && *value) {
 299                 char *end;
 300                 long val = strtol(value, &end, 0);
 301                 *ret = val * get_unit_factor(end);
 302                 return 1;
 303         }
 304         return 0;
 305 }
 306
 307 int git_parse_ulong(const char *value, unsigned long *ret)
 308 {
 309         if (value && *value) {
 310                 char *end;
 311                 unsigned long val = strtoul(value, &end, 0);
 312                 *ret = val * get_unit_factor(end);
 313                 return 1;
 314         }
 315         return 0;
 316 }
 317
 318 int git_config_int(const char *name, const char *value)
 319 {
 320         long ret;
 321         if (!git_parse_long(value, &ret))
 322                 die("bad config value for '%s' in %s", name, config_file_name);
 323         return ret;
 324 }
 325
 326 unsigned long git_config_ulong(const char *name, const char *value)
 327 {
 328         unsigned long ret;
 329         if (!git_parse_ulong(value, &ret))
 330                 die("bad config value for '%s' in %s", name, config_file_name);
 331         return ret;
 332 }
 333
 334 int git_config_bool(const char *name, const char *value)
 335 {
 336         if (!value)
 337                 return 1;
 338         if (!*value)
 339                 return 0;
 340         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 341                 return 1;
 342         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 343                 return 0;
 344         return git_config_int(name, value) != 0;
 345 }
 346
 347 int git_default_config(const char *var, const char *value)
 348 {
 349         /* This needs a better name */
 350         if (!strcmp(var, "core.filemode")) {
 351                 trust_executable_bit = git_config_bool(var, value);
 352                 return 0;
 353         }
 354
 355         if (!strcmp(var, "core.quotepath")) {
 356                 quote_path_fully = git_config_bool(var, value);
 357                 return 0;
 358         }
 359
 360         if (!strcmp(var, "core.symlinks")) {
 361                 has_symlinks = git_config_bool(var, value);
 362                 return 0;
 363         }
 364
 365         if (!strcmp(var, "core.bare")) {
 366                 is_bare_repository_cfg = git_config_bool(var, value);
 367                 return 0;
 368         }
 369
 370         if (!strcmp(var, "core.ignorestat")) {
 371                 assume_unchanged = git_config_bool(var, value);
 372                 return 0;
 373         }
 374
 375         if (!strcmp(var, "core.prefersymlinkrefs")) {
 376                 prefer_symlink_refs = git_config_bool(var, value);
 377                 return 0;
 378         }
 379
 380         if (!strcmp(var, "core.logallrefupdates")) {
 381                 log_all_ref_updates = git_config_bool(var, value);
 382                 return 0;
 383         }
 384
 385         if (!strcmp(var, "core.warnambiguousrefs")) {
 386                 warn_ambiguous_refs = git_config_bool(var, value);
 387                 return 0;
 388         }
 389
 390         if (!strcmp(var, "core.loosecompression")) {
 391                 int level = git_config_int(var, value);
 392                 if (level == -1)
 393                         level = Z_DEFAULT_COMPRESSION;
 394                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 395                         die("bad zlib compression level %d", level);
 396                 zlib_compression_level = level;
 397                 zlib_compression_seen = 1;
 398                 return 0;
 399         }
 400
 401         if (!strcmp(var, "core.compression")) {
 402                 int level = git_config_int(var, value);
 403                 if (level == -1)
 404                         level = Z_DEFAULT_COMPRESSION;
 405                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 406                         die("bad zlib compression level %d", level);
 407                 core_compression_level = level;
 408                 core_compression_seen = 1;
 409                 if (!zlib_compression_seen)
 410                         zlib_compression_level = level;
 411                 return 0;
 412         }
 413
 414         if (!strcmp(var, "core.packedgitwindowsize")) {
 415                 int pgsz_x2 = getpagesize() * 2;
 416                 packed_git_window_size = git_config_int(var, value);
 417
 418                 /* This value must be multiple of (pagesize * 2) */
 419                 packed_git_window_size /= pgsz_x2;
 420                 if (packed_git_window_size < 1)
 421                         packed_git_window_size = 1;
 422                 packed_git_window_size *= pgsz_x2;
 423                 return 0;
 424         }
 425
 426         if (!strcmp(var, "core.packedgitlimit")) {
 427                 packed_git_limit = git_config_int(var, value);
 428                 return 0;
 429         }
 430
 431         if (!strcmp(var, "core.deltabasecachelimit")) {
 432                 delta_base_cache_limit = git_config_int(var, value);
 433                 return 0;
 434         }
 435
 436         if (!strcmp(var, "core.autocrlf")) {
 437                 if (value && !strcasecmp(value, "input")) {
 438                         auto_crlf = -1;
 439                         return 0;
 440                 }
 441                 auto_crlf = git_config_bool(var, value);
 442                 return 0;
 443         }
 444
 445         if (!strcmp(var, "user.name")) {
 446                 strlcpy(git_default_name, value, sizeof(git_default_name));
 447                 return 0;
 448         }
 449
 450         if (!strcmp(var, "user.email")) {
 451                 strlcpy(git_default_email, value, sizeof(git_default_email));
 452                 return 0;
 453         }
 454
 455         if (!strcmp(var, "i18n.commitencoding")) {
 456                 git_commit_encoding = xstrdup(value);
 457                 return 0;
 458         }
 459
 460         if (!strcmp(var, "i18n.logoutputencoding")) {
 461                 git_log_output_encoding = xstrdup(value);
 462                 return 0;
 463         }
 464
 465
 466         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 467                 pager_use_color = git_config_bool(var,value);
 468                 return 0;
 469         }
 470
 471         if (!strcmp(var, "core.pager")) {
 472                 pager_program = xstrdup(value);
 473                 return 0;
 474         }
 475
 476         if (!strcmp(var, "core.editor")) {
 477                 editor_program = xstrdup(value);
 478                 return 0;
 479         }
 480
 481         if (!strcmp(var, "core.whitespace")) {
 482                 whitespace_rule = parse_whitespace_rule(value);
 483                 return 0;
 484         }
 485
 486         /* Add other config variables here and to Documentation/config.txt. */
 487         return 0;
 488 }
 489
 490 int git_config_from_file(config_fn_t fn, const char *filename)
 491 {
 492         int ret;
 493         FILE *f = fopen(filename, "r");
 494
 495         ret = -1;
 496         if (f) {
 497                 config_file = f;
 498                 config_file_name = filename;
 499                 config_linenr = 1;
 500                 ret = git_parse_file(fn);
 501                 fclose(f);
 502                 config_file_name = NULL;
 503         }
 504         return ret;
 505 }
 506
 507 int git_config(config_fn_t fn)
 508 {
 509         int ret = 0;
 510         char *repo_config = NULL;
 511         const char *home = NULL, *filename;
 512
 513         /* $GIT_CONFIG makes git read _only_ the given config file,
 514          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 515          * global config file, the same way it would the per-repository
 516          * config file otherwise. */
 517         filename = getenv(CONFIG_ENVIRONMENT);
 518         if (!filename) {
 519                 if (!access(ETC_GITCONFIG, R_OK))
 520                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 521                 home = getenv("HOME");
 522                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 523                 if (!filename)
 524                         filename = repo_config = xstrdup(git_path("config"));
 525         }
 526
 527         if (home) {
 528                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 529                 if (!access(user_config, R_OK))
 530                         ret = git_config_from_file(fn, user_config);
 531                 free(user_config);
 532         }
 533
 534         ret += git_config_from_file(fn, filename);
 535         free(repo_config);
 536         return ret;
 537 }
 538
 539 /*
 540  * Find all the stuff for git_config_set() below.
 541  */
 542
 543 #define MAX_MATCHES 512
 544
 545 static struct {
 546         int baselen;
 547         char* key;
 548         int do_not_match;
 549         regex_t* value_regex;
 550         int multi_replace;
 551         size_t offset[MAX_MATCHES];
 552         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 553         int seen;
 554 } store;
 555
 556 static int matches(const char* key, const char* value)
 557 {
 558         return !strcmp(key, store.key) &&
 559                 (store.value_regex == NULL ||
 560                  (store.do_not_match ^
 561                   !regexec(store.value_regex, value, 0, NULL, 0)));
 562 }
 563
 564 static int store_aux(const char* key, const char* value)
 565 {
 566         const char *ep;
 567         size_t section_len;
 568
 569         switch (store.state) {
 570         case KEY_SEEN:
 571                 if (matches(key, value)) {
 572                         if (store.seen == 1 && store.multi_replace == 0) {
 573                                 fprintf(stderr,
 574                                         "Warning: %s has multiple values\n",
 575                                         key);
 576                         } else if (store.seen >= MAX_MATCHES) {
 577                                 fprintf(stderr, "Too many matches\n");
 578                                 return 1;
 579                         }
 580
 581                         store.offset[store.seen] = ftell(config_file);
 582                         store.seen++;
 583                 }
 584                 break;
 585         case SECTION_SEEN:
 586                 /*
 587                  * What we are looking for is in store.key (both
 588                  * section and var), and its section part is baselen
 589                  * long.  We found key (again, both section and var).
 590                  * We would want to know if this key is in the same
 591                  * section as what we are looking for.  We already
 592                  * know we are in the same section as what should
 593                  * hold store.key.
 594                  */
 595                 ep = strrchr(key, '.');
 596                 section_len = ep - key;
 597
 598                 if ((section_len != store.baselen) ||
 599                     memcmp(key, store.key, section_len+1)) {
 600                         store.state = SECTION_END_SEEN;
 601                         break;
 602                 }
 603
 604                 /*
 605                  * Do not increment matches: this is no match, but we
 606                  * just made sure we are in the desired section.
 607                  */
 608                 store.offset[store.seen] = ftell(config_file);
 609                 /* fallthru */
 610         case SECTION_END_SEEN:
 611         case START:
 612                 if (matches(key, value)) {
 613                         store.offset[store.seen] = ftell(config_file);
 614                         store.state = KEY_SEEN;
 615                         store.seen++;
 616                 } else {
 617                         if (strrchr(key, '.') - key == store.baselen &&
 618                               !strncmp(key, store.key, store.baselen)) {
 619                                         store.state = SECTION_SEEN;
 620                                         store.offset[store.seen] = ftell(config_file);
 621                         }
 622                 }
 623         }
 624         return 0;
 625 }
 626
 627 static int write_error(void)
 628 {
 629         fprintf(stderr, "Failed to write new configuration file\n");
 630
 631         /* Same error code as "failed to rename". */
 632         return 4;
 633 }
 634
 635 static int store_write_section(int fd, const char* key)
 636 {
 637         const char *dot = strchr(key, '.');
 638         int len1 = store.baselen, len2 = -1;
 639
 640         dot = strchr(key, '.');
 641         if (dot) {
 642                 int dotlen = dot - key;
 643                 if (dotlen < len1) {
 644                         len2 = len1 - dotlen - 1;
 645                         len1 = dotlen;
 646                 }
 647         }
 648
 649         if (write_in_full(fd, "[", 1) != 1 ||
 650             write_in_full(fd, key, len1) != len1)
 651                 return 0;
 652         if (len2 >= 0) {
 653                 if (write_in_full(fd, " \"", 2) != 2)
 654                         return 0;
 655                 while (--len2 >= 0) {
 656                         unsigned char c = *++dot;
 657                         if (c == '"')
 658                                 if (write_in_full(fd, "\\", 1) != 1)
 659                                         return 0;
 660                         if (write_in_full(fd, &c, 1) != 1)
 661                                 return 0;
 662                 }
 663                 if (write_in_full(fd, "\"", 1) != 1)
 664                         return 0;
 665         }
 666         if (write_in_full(fd, "]\n", 2) != 2)
 667                 return 0;
 668
 669         return 1;
 670 }
 671
 672 static int store_write_pair(int fd, const char* key, const char* value)
 673 {
 674         int i;
 675         int length = strlen(key+store.baselen+1);
 676         int quote = 0;
 677
 678         /* Check to see if the value needs to be quoted. */
 679         if (value[0] == ' ')
 680                 quote = 1;
 681         for (i = 0; value[i]; i++)
 682                 if (value[i] == ';' || value[i] == '#')
 683                         quote = 1;
 684         if (value[i-1] == ' ')
 685                 quote = 1;
 686
 687         if (write_in_full(fd, "\t", 1) != 1 ||
 688             write_in_full(fd, key+store.baselen+1, length) != length ||
 689             write_in_full(fd, " = ", 3) != 3)
 690                 return 0;
 691         if (quote && write_in_full(fd, "\"", 1) != 1)
 692                 return 0;
 693         for (i = 0; value[i]; i++)
 694                 switch (value[i]) {
 695                 case '\n':
 696                         if (write_in_full(fd, "\\n", 2) != 2)
 697                                 return 0;
 698                         break;
 699                 case '\t':
 700                         if (write_in_full(fd, "\\t", 2) != 2)
 701                                 return 0;
 702                         break;
 703                 case '"':
 704                 case '\\':
 705                         if (write_in_full(fd, "\\", 1) != 1)
 706                                 return 0;
 707                 default:
 708                         if (write_in_full(fd, value+i, 1) != 1)
 709                                 return 0;
 710                         break;
 711                 }
 712         if (quote && write_in_full(fd, "\"", 1) != 1)
 713                 return 0;
 714         if (write_in_full(fd, "\n", 1) != 1)
 715                 return 0;
 716         return 1;
 717 }
 718
 719 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 720         size_t offset_, int* found_bracket)
 721 {
 722         size_t equal_offset = size, bracket_offset = size;
 723         ssize_t offset;
 724
 725         for (offset = offset_-2; offset > 0
 726                         && contents[offset] != '\n'; offset--)
 727                 switch (contents[offset]) {
 728                         case '=': equal_offset = offset; break;
 729                         case ']': bracket_offset = offset; break;
 730                 }
 731         if (bracket_offset < equal_offset) {
 732                 *found_bracket = 1;
 733                 offset = bracket_offset+1;
 734         } else
 735                 offset++;
 736
 737         return offset;
 738 }
 739
 740 int git_config_set(const char* key, const char* value)
 741 {
 742         return git_config_set_multivar(key, value, NULL, 0);
 743 }
 744
 745 /*
 746  * If value==NULL, unset in (remove from) config,
 747  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 748  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 749  *     else all matching key/values (regardless how many) are removed,
 750  *     before the new pair is written.
 751  *
 752  * Returns 0 on success.
 753  *
 754  * This function does this:
 755  *
 756  * - it locks the config file by creating ".git/config.lock"
 757  *
 758  * - it then parses the config using store_aux() as validator to find
 759  *   the position on the key/value pair to replace. If it is to be unset,
 760  *   it must be found exactly once.
 761  *
 762  * - the config file is mmap()ed and the part before the match (if any) is
 763  *   written to the lock file, then the changed part and the rest.
 764  *
 765  * - the config file is removed and the lock file rename()d to it.
 766  *
 767  */
 768 int git_config_set_multivar(const char* key, const char* value,
 769         const char* value_regex, int multi_replace)
 770 {
 771         int i, dot;
 772         int fd = -1, in_fd;
 773         int ret;
 774         char* config_filename;
 775         struct lock_file *lock = NULL;
 776         const char* last_dot = strrchr(key, '.');
 777
 778         config_filename = getenv(CONFIG_ENVIRONMENT);
 779         if (!config_filename) {
 780                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 781                 if (!config_filename)
 782                         config_filename  = git_path("config");
 783         }
 784         config_filename = xstrdup(config_filename);
 785
 786         /*
 787          * Since "key" actually contains the section name and the real
 788          * key name separated by a dot, we have to know where the dot is.
 789          */
 790
 791         if (last_dot == NULL) {
 792                 fprintf(stderr, "key does not contain a section: %s\n", key);
 793                 ret = 2;
 794                 goto out_free;
 795         }
 796         store.baselen = last_dot - key;
 797
 798         store.multi_replace = multi_replace;
 799
 800         /*
 801          * Validate the key and while at it, lower case it for matching.
 802          */
 803         store.key = xmalloc(strlen(key) + 1);
 804         dot = 0;
 805         for (i = 0; key[i]; i++) {
 806                 unsigned char c = key[i];
 807                 if (c == '.')
 808                         dot = 1;
 809                 /* Leave the extended basename untouched.. */
 810                 if (!dot || i > store.baselen) {
 811                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 812                                 fprintf(stderr, "invalid key: %s\n", key);
 813                                 free(store.key);
 814                                 ret = 1;
 815                                 goto out_free;
 816                         }
 817                         c = tolower(c);
 818                 } else if (c == '\n') {
 819                         fprintf(stderr, "invalid key (newline): %s\n", key);
 820                         free(store.key);
 821                         ret = 1;
 822                         goto out_free;
 823                 }
 824                 store.key[i] = c;
 825         }
 826         store.key[i] = 0;
 827
 828         /*
 829          * The lock serves a purpose in addition to locking: the new
 830          * contents of .git/config will be written into it.
 831          */
 832         lock = xcalloc(sizeof(struct lock_file), 1);
 833         fd = hold_lock_file_for_update(lock, config_filename, 0);
 834         if (fd < 0) {
 835                 fprintf(stderr, "could not lock config file\n");
 836                 free(store.key);
 837                 ret = -1;
 838                 goto out_free;
 839         }
 840
 841         /*
 842          * If .git/config does not exist yet, write a minimal version.
 843          */
 844         in_fd = open(config_filename, O_RDONLY);
 845         if ( in_fd < 0 ) {
 846                 free(store.key);
 847
 848                 if ( ENOENT != errno ) {
 849                         error("opening %s: %s", config_filename,
 850                               strerror(errno));
 851                         ret = 3; /* same as "invalid config file" */
 852                         goto out_free;
 853                 }
 854                 /* if nothing to unset, error out */
 855                 if (value == NULL) {
 856                         ret = 5;
 857                         goto out_free;
 858                 }
 859
 860                 store.key = (char*)key;
 861                 if (!store_write_section(fd, key) ||
 862                     !store_write_pair(fd, key, value))
 863                         goto write_err_out;
 864         } else {
 865                 struct stat st;
 866                 char* contents;
 867                 size_t contents_sz, copy_begin, copy_end;
 868                 int i, new_line = 0;
 869
 870                 if (value_regex == NULL)
 871                         store.value_regex = NULL;
 872                 else {
 873                         if (value_regex[0] == '!') {
 874                                 store.do_not_match = 1;
 875                                 value_regex++;
 876                         } else
 877                                 store.do_not_match = 0;
 878
 879                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 880                         if (regcomp(store.value_regex, value_regex,
 881                                         REG_EXTENDED)) {
 882                                 fprintf(stderr, "Invalid pattern: %s\n",
 883                                         value_regex);
 884                                 free(store.value_regex);
 885                                 ret = 6;
 886                                 goto out_free;
 887                         }
 888                 }
 889
 890                 store.offset[0] = 0;
 891                 store.state = START;
 892                 store.seen = 0;
 893
 894                 /*
 895                  * After this, store.offset will contain the *end* offset
 896                  * of the last match, or remain at 0 if no match was found.
 897                  * As a side effect, we make sure to transform only a valid
 898                  * existing config file.
 899                  */
 900                 if (git_config_from_file(store_aux, config_filename)) {
 901                         fprintf(stderr, "invalid config file\n");
 902                         free(store.key);
 903                         if (store.value_regex != NULL) {
 904                                 regfree(store.value_regex);
 905                                 free(store.value_regex);
 906                         }
 907                         ret = 3;
 908                         goto out_free;
 909                 }
 910
 911                 free(store.key);
 912                 if (store.value_regex != NULL) {
 913                         regfree(store.value_regex);
 914                         free(store.value_regex);
 915                 }
 916
 917                 /* if nothing to unset, or too many matches, error out */
 918                 if ((store.seen == 0 && value == NULL) ||
 919                                 (store.seen > 1 && multi_replace == 0)) {
 920                         ret = 5;
 921                         goto out_free;
 922                 }
 923
 924                 fstat(in_fd, &st);
 925                 contents_sz = xsize_t(st.st_size);
 926                 contents = xmmap(NULL, contents_sz, PROT_READ,
 927                         MAP_PRIVATE, in_fd, 0);
 928                 close(in_fd);
 929
 930                 if (store.seen == 0)
 931                         store.seen = 1;
 932
 933                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 934                         if (store.offset[i] == 0) {
 935                                 store.offset[i] = copy_end = contents_sz;
 936                         } else if (store.state != KEY_SEEN) {
 937                                 copy_end = store.offset[i];
 938                         } else
 939                                 copy_end = find_beginning_of_line(
 940                                         contents, contents_sz,
 941                                         store.offset[i]-2, &new_line);
 942
 943                         /* write the first part of the config */
 944                         if (copy_end > copy_begin) {
 945                                 if (write_in_full(fd, contents + copy_begin,
 946                                                   copy_end - copy_begin) <
 947                                     copy_end - copy_begin)
 948                                         goto write_err_out;
 949                                 if (new_line &&
 950                                     write_in_full(fd, "\n", 1) != 1)
 951                                         goto write_err_out;
 952                         }
 953                         copy_begin = store.offset[i];
 954                 }
 955
 956                 /* write the pair (value == NULL means unset) */
 957                 if (value != NULL) {
 958                         if (store.state == START) {
 959                                 if (!store_write_section(fd, key))
 960                                         goto write_err_out;
 961                         }
 962                         if (!store_write_pair(fd, key, value))
 963                                 goto write_err_out;
 964                 }
 965
 966                 /* write the rest of the config */
 967                 if (copy_begin < contents_sz)
 968                         if (write_in_full(fd, contents + copy_begin,
 969                                           contents_sz - copy_begin) <
 970                             contents_sz - copy_begin)
 971                                 goto write_err_out;
 972
 973                 munmap(contents, contents_sz);
 974         }
 975
 976         if (close(fd) || commit_lock_file(lock) < 0) {
 977                 fprintf(stderr, "Cannot commit config file!\n");
 978                 ret = 4;
 979                 goto out_free;
 980         }
 981
 982         /* fd is closed, so don't try to close it below. */
 983         fd = -1;
 984         /*
 985          * lock is committed, so don't try to roll it back below.
 986          * NOTE: Since lockfile.c keeps a linked list of all created
 987          * lock_file structures, it isn't safe to free(lock).  It's
 988          * better to just leave it hanging around.
 989          */
 990         lock = NULL;
 991         ret = 0;
 992
 993 out_free:
 994         if (0 <= fd)
 995                 close(fd);
 996         if (lock)
 997                 rollback_lock_file(lock);
 998         free(config_filename);
 999         return ret;
1000
1001 write_err_out:
1002         ret = write_error();
1003         goto out_free;
1004
1005 }
1006
1007 static int section_name_match (const char *buf, const char *name)
1008 {
1009         int i = 0, j = 0, dot = 0;
1010         for (; buf[i] && buf[i] != ']'; i++) {
1011                 if (!dot && isspace(buf[i])) {
1012                         dot = 1;
1013                         if (name[j++] != '.')
1014                                 break;
1015                         for (i++; isspace(buf[i]); i++)
1016                                 ; /* do nothing */
1017                         if (buf[i] != '"')
1018                                 break;
1019                         continue;
1020                 }
1021                 if (buf[i] == '\\' && dot)
1022                         i++;
1023                 else if (buf[i] == '"' && dot) {
1024                         for (i++; isspace(buf[i]); i++)
1025                                 ; /* do_nothing */
1026                         break;
1027                 }
1028                 if (buf[i] != name[j++])
1029                         break;
1030         }
1031         return (buf[i] == ']' && name[j] == 0);
1032 }
1033
1034 /* if new_name == NULL, the section is removed instead */
1035 int git_config_rename_section(const char *old_name, const char *new_name)
1036 {
1037         int ret = 0, remove = 0;
1038         char *config_filename;
1039         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1040         int out_fd;
1041         char buf[1024];
1042
1043         config_filename = getenv(CONFIG_ENVIRONMENT);
1044         if (!config_filename) {
1045                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1046                 if (!config_filename)
1047                         config_filename  = git_path("config");
1048         }
1049         config_filename = xstrdup(config_filename);
1050         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1051         if (out_fd < 0) {
1052                 ret = error("Could not lock config file!");
1053                 goto out;
1054         }
1055
1056         if (!(config_file = fopen(config_filename, "rb"))) {
1057                 /* no config file means nothing to rename, no error */
1058                 goto unlock_and_out;
1059         }
1060
1061         while (fgets(buf, sizeof(buf), config_file)) {
1062                 int i;
1063                 int length;
1064                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1065                         ; /* do nothing */
1066                 if (buf[i] == '[') {
1067                         /* it's a section */
1068                         if (section_name_match (&buf[i+1], old_name)) {
1069                                 ret++;
1070                                 if (new_name == NULL) {
1071                                         remove = 1;
1072                                         continue;
1073                                 }
1074                                 store.baselen = strlen(new_name);
1075                                 if (!store_write_section(out_fd, new_name)) {
1076                                         ret = write_error();
1077                                         goto out;
1078                                 }
1079                                 continue;
1080                         }
1081                         remove = 0;
1082                 }
1083                 if (remove)
1084                         continue;
1085                 length = strlen(buf);
1086                 if (write_in_full(out_fd, buf, length) != length) {
1087                         ret = write_error();
1088                         goto out;
1089                 }
1090         }
1091         fclose(config_file);
1092  unlock_and_out:
1093         if (close(out_fd) || commit_lock_file(lock) < 0)
1094                         ret = error("Cannot commit config file!");
1095  out:
1096         free(config_filename);
1097         return ret;
1098 }