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         { "indent-with-non-tab", WS_INDENT_WITH_NON_TAB },
 256 };
 257
 258 static unsigned parse_whitespace_rule(const char *string)
 259 {
 260         unsigned rule = WS_DEFAULT_RULE;
 261
 262         while (string) {
 263                 int i;
 264                 size_t len;
 265                 const char *ep;
 266                 int negated = 0;
 267
 268                 string = string + strspn(string, ", \t\n\r");
 269                 ep = strchr(string, ',');
 270                 if (!ep)
 271                         len = strlen(string);
 272                 else
 273                         len = ep - string;
 274
 275                 if (*string == '-') {
 276                         negated = 1;
 277                         string++;
 278                         len--;
 279                 }
 280                 if (!len)
 281                         break;
 282                 for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++) {
 283                         if (strncmp(whitespace_rule_names[i].rule_name,
 284                                     string, len))
 285                                 continue;
 286                         if (negated)
 287                                 rule &= ~whitespace_rule_names[i].rule_bits;
 288                         else
 289                                 rule |= whitespace_rule_names[i].rule_bits;
 290                         break;
 291                 }
 292                 string = ep;
 293         }
 294         return rule;
 295 }
 296
 297 int git_parse_long(const char *value, long *ret)
 298 {
 299         if (value && *value) {
 300                 char *end;
 301                 long val = strtol(value, &end, 0);
 302                 *ret = val * get_unit_factor(end);
 303                 return 1;
 304         }
 305         return 0;
 306 }
 307
 308 int git_parse_ulong(const char *value, unsigned long *ret)
 309 {
 310         if (value && *value) {
 311                 char *end;
 312                 unsigned long val = strtoul(value, &end, 0);
 313                 *ret = val * get_unit_factor(end);
 314                 return 1;
 315         }
 316         return 0;
 317 }
 318
 319 int git_config_int(const char *name, const char *value)
 320 {
 321         long ret;
 322         if (!git_parse_long(value, &ret))
 323                 die("bad config value for '%s' in %s", name, config_file_name);
 324         return ret;
 325 }
 326
 327 unsigned long git_config_ulong(const char *name, const char *value)
 328 {
 329         unsigned long ret;
 330         if (!git_parse_ulong(value, &ret))
 331                 die("bad config value for '%s' in %s", name, config_file_name);
 332         return ret;
 333 }
 334
 335 int git_config_bool(const char *name, const char *value)
 336 {
 337         if (!value)
 338                 return 1;
 339         if (!*value)
 340                 return 0;
 341         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 342                 return 1;
 343         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 344                 return 0;
 345         return git_config_int(name, value) != 0;
 346 }
 347
 348 int git_default_config(const char *var, const char *value)
 349 {
 350         /* This needs a better name */
 351         if (!strcmp(var, "core.filemode")) {
 352                 trust_executable_bit = git_config_bool(var, value);
 353                 return 0;
 354         }
 355
 356         if (!strcmp(var, "core.quotepath")) {
 357                 quote_path_fully = git_config_bool(var, value);
 358                 return 0;
 359         }
 360
 361         if (!strcmp(var, "core.symlinks")) {
 362                 has_symlinks = git_config_bool(var, value);
 363                 return 0;
 364         }
 365
 366         if (!strcmp(var, "core.bare")) {
 367                 is_bare_repository_cfg = git_config_bool(var, value);
 368                 return 0;
 369         }
 370
 371         if (!strcmp(var, "core.ignorestat")) {
 372                 assume_unchanged = git_config_bool(var, value);
 373                 return 0;
 374         }
 375
 376         if (!strcmp(var, "core.prefersymlinkrefs")) {
 377                 prefer_symlink_refs = git_config_bool(var, value);
 378                 return 0;
 379         }
 380
 381         if (!strcmp(var, "core.logallrefupdates")) {
 382                 log_all_ref_updates = git_config_bool(var, value);
 383                 return 0;
 384         }
 385
 386         if (!strcmp(var, "core.warnambiguousrefs")) {
 387                 warn_ambiguous_refs = git_config_bool(var, value);
 388                 return 0;
 389         }
 390
 391         if (!strcmp(var, "core.loosecompression")) {
 392                 int level = git_config_int(var, value);
 393                 if (level == -1)
 394                         level = Z_DEFAULT_COMPRESSION;
 395                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 396                         die("bad zlib compression level %d", level);
 397                 zlib_compression_level = level;
 398                 zlib_compression_seen = 1;
 399                 return 0;
 400         }
 401
 402         if (!strcmp(var, "core.compression")) {
 403                 int level = git_config_int(var, value);
 404                 if (level == -1)
 405                         level = Z_DEFAULT_COMPRESSION;
 406                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 407                         die("bad zlib compression level %d", level);
 408                 core_compression_level = level;
 409                 core_compression_seen = 1;
 410                 if (!zlib_compression_seen)
 411                         zlib_compression_level = level;
 412                 return 0;
 413         }
 414
 415         if (!strcmp(var, "core.packedgitwindowsize")) {
 416                 int pgsz_x2 = getpagesize() * 2;
 417                 packed_git_window_size = git_config_int(var, value);
 418
 419                 /* This value must be multiple of (pagesize * 2) */
 420                 packed_git_window_size /= pgsz_x2;
 421                 if (packed_git_window_size < 1)
 422                         packed_git_window_size = 1;
 423                 packed_git_window_size *= pgsz_x2;
 424                 return 0;
 425         }
 426
 427         if (!strcmp(var, "core.packedgitlimit")) {
 428                 packed_git_limit = git_config_int(var, value);
 429                 return 0;
 430         }
 431
 432         if (!strcmp(var, "core.deltabasecachelimit")) {
 433                 delta_base_cache_limit = git_config_int(var, value);
 434                 return 0;
 435         }
 436
 437         if (!strcmp(var, "core.autocrlf")) {
 438                 if (value && !strcasecmp(value, "input")) {
 439                         auto_crlf = -1;
 440                         return 0;
 441                 }
 442                 auto_crlf = git_config_bool(var, value);
 443                 return 0;
 444         }
 445
 446         if (!strcmp(var, "user.name")) {
 447                 strlcpy(git_default_name, value, sizeof(git_default_name));
 448                 return 0;
 449         }
 450
 451         if (!strcmp(var, "user.email")) {
 452                 strlcpy(git_default_email, value, sizeof(git_default_email));
 453                 return 0;
 454         }
 455
 456         if (!strcmp(var, "i18n.commitencoding")) {
 457                 git_commit_encoding = xstrdup(value);
 458                 return 0;
 459         }
 460
 461         if (!strcmp(var, "i18n.logoutputencoding")) {
 462                 git_log_output_encoding = xstrdup(value);
 463                 return 0;
 464         }
 465
 466
 467         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 468                 pager_use_color = git_config_bool(var,value);
 469                 return 0;
 470         }
 471
 472         if (!strcmp(var, "core.pager")) {
 473                 pager_program = xstrdup(value);
 474                 return 0;
 475         }
 476
 477         if (!strcmp(var, "core.editor")) {
 478                 editor_program = xstrdup(value);
 479                 return 0;
 480         }
 481
 482         if (!strcmp(var, "core.whitespace")) {
 483                 whitespace_rule = parse_whitespace_rule(value);
 484                 return 0;
 485         }
 486
 487         /* Add other config variables here and to Documentation/config.txt. */
 488         return 0;
 489 }
 490
 491 int git_config_from_file(config_fn_t fn, const char *filename)
 492 {
 493         int ret;
 494         FILE *f = fopen(filename, "r");
 495
 496         ret = -1;
 497         if (f) {
 498                 config_file = f;
 499                 config_file_name = filename;
 500                 config_linenr = 1;
 501                 ret = git_parse_file(fn);
 502                 fclose(f);
 503                 config_file_name = NULL;
 504         }
 505         return ret;
 506 }
 507
 508 int git_config(config_fn_t fn)
 509 {
 510         int ret = 0;
 511         char *repo_config = NULL;
 512         const char *home = NULL, *filename;
 513
 514         /* $GIT_CONFIG makes git read _only_ the given config file,
 515          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 516          * global config file, the same way it would the per-repository
 517          * config file otherwise. */
 518         filename = getenv(CONFIG_ENVIRONMENT);
 519         if (!filename) {
 520                 if (!access(ETC_GITCONFIG, R_OK))
 521                         ret += git_config_from_file(fn, ETC_GITCONFIG);
 522                 home = getenv("HOME");
 523                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 524                 if (!filename)
 525                         filename = repo_config = xstrdup(git_path("config"));
 526         }
 527
 528         if (home) {
 529                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 530                 if (!access(user_config, R_OK))
 531                         ret = git_config_from_file(fn, user_config);
 532                 free(user_config);
 533         }
 534
 535         ret += git_config_from_file(fn, filename);
 536         free(repo_config);
 537         return ret;
 538 }
 539
 540 /*
 541  * Find all the stuff for git_config_set() below.
 542  */
 543
 544 #define MAX_MATCHES 512
 545
 546 static struct {
 547         int baselen;
 548         char* key;
 549         int do_not_match;
 550         regex_t* value_regex;
 551         int multi_replace;
 552         size_t offset[MAX_MATCHES];
 553         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 554         int seen;
 555 } store;
 556
 557 static int matches(const char* key, const char* value)
 558 {
 559         return !strcmp(key, store.key) &&
 560                 (store.value_regex == NULL ||
 561                  (store.do_not_match ^
 562                   !regexec(store.value_regex, value, 0, NULL, 0)));
 563 }
 564
 565 static int store_aux(const char* key, const char* value)
 566 {
 567         const char *ep;
 568         size_t section_len;
 569
 570         switch (store.state) {
 571         case KEY_SEEN:
 572                 if (matches(key, value)) {
 573                         if (store.seen == 1 && store.multi_replace == 0) {
 574                                 fprintf(stderr,
 575                                         "Warning: %s has multiple values\n",
 576                                         key);
 577                         } else if (store.seen >= MAX_MATCHES) {
 578                                 fprintf(stderr, "Too many matches\n");
 579                                 return 1;
 580                         }
 581
 582                         store.offset[store.seen] = ftell(config_file);
 583                         store.seen++;
 584                 }
 585                 break;
 586         case SECTION_SEEN:
 587                 /*
 588                  * What we are looking for is in store.key (both
 589                  * section and var), and its section part is baselen
 590                  * long.  We found key (again, both section and var).
 591                  * We would want to know if this key is in the same
 592                  * section as what we are looking for.  We already
 593                  * know we are in the same section as what should
 594                  * hold store.key.
 595                  */
 596                 ep = strrchr(key, '.');
 597                 section_len = ep - key;
 598
 599                 if ((section_len != store.baselen) ||
 600                     memcmp(key, store.key, section_len+1)) {
 601                         store.state = SECTION_END_SEEN;
 602                         break;
 603                 }
 604
 605                 /*
 606                  * Do not increment matches: this is no match, but we
 607                  * just made sure we are in the desired section.
 608                  */
 609                 store.offset[store.seen] = ftell(config_file);
 610                 /* fallthru */
 611         case SECTION_END_SEEN:
 612         case START:
 613                 if (matches(key, value)) {
 614                         store.offset[store.seen] = ftell(config_file);
 615                         store.state = KEY_SEEN;
 616                         store.seen++;
 617                 } else {
 618                         if (strrchr(key, '.') - key == store.baselen &&
 619                               !strncmp(key, store.key, store.baselen)) {
 620                                         store.state = SECTION_SEEN;
 621                                         store.offset[store.seen] = ftell(config_file);
 622                         }
 623                 }
 624         }
 625         return 0;
 626 }
 627
 628 static int write_error(void)
 629 {
 630         fprintf(stderr, "Failed to write new configuration file\n");
 631
 632         /* Same error code as "failed to rename". */
 633         return 4;
 634 }
 635
 636 static int store_write_section(int fd, const char* key)
 637 {
 638         const char *dot = strchr(key, '.');
 639         int len1 = store.baselen, len2 = -1;
 640
 641         dot = strchr(key, '.');
 642         if (dot) {
 643                 int dotlen = dot - key;
 644                 if (dotlen < len1) {
 645                         len2 = len1 - dotlen - 1;
 646                         len1 = dotlen;
 647                 }
 648         }
 649
 650         if (write_in_full(fd, "[", 1) != 1 ||
 651             write_in_full(fd, key, len1) != len1)
 652                 return 0;
 653         if (len2 >= 0) {
 654                 if (write_in_full(fd, " \"", 2) != 2)
 655                         return 0;
 656                 while (--len2 >= 0) {
 657                         unsigned char c = *++dot;
 658                         if (c == '"')
 659                                 if (write_in_full(fd, "\\", 1) != 1)
 660                                         return 0;
 661                         if (write_in_full(fd, &c, 1) != 1)
 662                                 return 0;
 663                 }
 664                 if (write_in_full(fd, "\"", 1) != 1)
 665                         return 0;
 666         }
 667         if (write_in_full(fd, "]\n", 2) != 2)
 668                 return 0;
 669
 670         return 1;
 671 }
 672
 673 static int store_write_pair(int fd, const char* key, const char* value)
 674 {
 675         int i;
 676         int length = strlen(key+store.baselen+1);
 677         int quote = 0;
 678
 679         /* Check to see if the value needs to be quoted. */
 680         if (value[0] == ' ')
 681                 quote = 1;
 682         for (i = 0; value[i]; i++)
 683                 if (value[i] == ';' || value[i] == '#')
 684                         quote = 1;
 685         if (value[i-1] == ' ')
 686                 quote = 1;
 687
 688         if (write_in_full(fd, "\t", 1) != 1 ||
 689             write_in_full(fd, key+store.baselen+1, length) != length ||
 690             write_in_full(fd, " = ", 3) != 3)
 691                 return 0;
 692         if (quote && write_in_full(fd, "\"", 1) != 1)
 693                 return 0;
 694         for (i = 0; value[i]; i++)
 695                 switch (value[i]) {
 696                 case '\n':
 697                         if (write_in_full(fd, "\\n", 2) != 2)
 698                                 return 0;
 699                         break;
 700                 case '\t':
 701                         if (write_in_full(fd, "\\t", 2) != 2)
 702                                 return 0;
 703                         break;
 704                 case '"':
 705                 case '\\':
 706                         if (write_in_full(fd, "\\", 1) != 1)
 707                                 return 0;
 708                 default:
 709                         if (write_in_full(fd, value+i, 1) != 1)
 710                                 return 0;
 711                         break;
 712                 }
 713         if (quote && write_in_full(fd, "\"", 1) != 1)
 714                 return 0;
 715         if (write_in_full(fd, "\n", 1) != 1)
 716                 return 0;
 717         return 1;
 718 }
 719
 720 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 721         size_t offset_, int* found_bracket)
 722 {
 723         size_t equal_offset = size, bracket_offset = size;
 724         ssize_t offset;
 725
 726         for (offset = offset_-2; offset > 0
 727                         && contents[offset] != '\n'; offset--)
 728                 switch (contents[offset]) {
 729                         case '=': equal_offset = offset; break;
 730                         case ']': bracket_offset = offset; break;
 731                 }
 732         if (bracket_offset < equal_offset) {
 733                 *found_bracket = 1;
 734                 offset = bracket_offset+1;
 735         } else
 736                 offset++;
 737
 738         return offset;
 739 }
 740
 741 int git_config_set(const char* key, const char* value)
 742 {
 743         return git_config_set_multivar(key, value, NULL, 0);
 744 }
 745
 746 /*
 747  * If value==NULL, unset in (remove from) config,
 748  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 749  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 750  *     else all matching key/values (regardless how many) are removed,
 751  *     before the new pair is written.
 752  *
 753  * Returns 0 on success.
 754  *
 755  * This function does this:
 756  *
 757  * - it locks the config file by creating ".git/config.lock"
 758  *
 759  * - it then parses the config using store_aux() as validator to find
 760  *   the position on the key/value pair to replace. If it is to be unset,
 761  *   it must be found exactly once.
 762  *
 763  * - the config file is mmap()ed and the part before the match (if any) is
 764  *   written to the lock file, then the changed part and the rest.
 765  *
 766  * - the config file is removed and the lock file rename()d to it.
 767  *
 768  */
 769 int git_config_set_multivar(const char* key, const char* value,
 770         const char* value_regex, int multi_replace)
 771 {
 772         int i, dot;
 773         int fd = -1, in_fd;
 774         int ret;
 775         char* config_filename;
 776         struct lock_file *lock = NULL;
 777         const char* last_dot = strrchr(key, '.');
 778
 779         config_filename = getenv(CONFIG_ENVIRONMENT);
 780         if (!config_filename) {
 781                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 782                 if (!config_filename)
 783                         config_filename  = git_path("config");
 784         }
 785         config_filename = xstrdup(config_filename);
 786
 787         /*
 788          * Since "key" actually contains the section name and the real
 789          * key name separated by a dot, we have to know where the dot is.
 790          */
 791
 792         if (last_dot == NULL) {
 793                 fprintf(stderr, "key does not contain a section: %s\n", key);
 794                 ret = 2;
 795                 goto out_free;
 796         }
 797         store.baselen = last_dot - key;
 798
 799         store.multi_replace = multi_replace;
 800
 801         /*
 802          * Validate the key and while at it, lower case it for matching.
 803          */
 804         store.key = xmalloc(strlen(key) + 1);
 805         dot = 0;
 806         for (i = 0; key[i]; i++) {
 807                 unsigned char c = key[i];
 808                 if (c == '.')
 809                         dot = 1;
 810                 /* Leave the extended basename untouched.. */
 811                 if (!dot || i > store.baselen) {
 812                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 813                                 fprintf(stderr, "invalid key: %s\n", key);
 814                                 free(store.key);
 815                                 ret = 1;
 816                                 goto out_free;
 817                         }
 818                         c = tolower(c);
 819                 } else if (c == '\n') {
 820                         fprintf(stderr, "invalid key (newline): %s\n", key);
 821                         free(store.key);
 822                         ret = 1;
 823                         goto out_free;
 824                 }
 825                 store.key[i] = c;
 826         }
 827         store.key[i] = 0;
 828
 829         /*
 830          * The lock serves a purpose in addition to locking: the new
 831          * contents of .git/config will be written into it.
 832          */
 833         lock = xcalloc(sizeof(struct lock_file), 1);
 834         fd = hold_lock_file_for_update(lock, config_filename, 0);
 835         if (fd < 0) {
 836                 fprintf(stderr, "could not lock config file\n");
 837                 free(store.key);
 838                 ret = -1;
 839                 goto out_free;
 840         }
 841
 842         /*
 843          * If .git/config does not exist yet, write a minimal version.
 844          */
 845         in_fd = open(config_filename, O_RDONLY);
 846         if ( in_fd < 0 ) {
 847                 free(store.key);
 848
 849                 if ( ENOENT != errno ) {
 850                         error("opening %s: %s", config_filename,
 851                               strerror(errno));
 852                         ret = 3; /* same as "invalid config file" */
 853                         goto out_free;
 854                 }
 855                 /* if nothing to unset, error out */
 856                 if (value == NULL) {
 857                         ret = 5;
 858                         goto out_free;
 859                 }
 860
 861                 store.key = (char*)key;
 862                 if (!store_write_section(fd, key) ||
 863                     !store_write_pair(fd, key, value))
 864                         goto write_err_out;
 865         } else {
 866                 struct stat st;
 867                 char* contents;
 868                 size_t contents_sz, copy_begin, copy_end;
 869                 int i, new_line = 0;
 870
 871                 if (value_regex == NULL)
 872                         store.value_regex = NULL;
 873                 else {
 874                         if (value_regex[0] == '!') {
 875                                 store.do_not_match = 1;
 876                                 value_regex++;
 877                         } else
 878                                 store.do_not_match = 0;
 879
 880                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 881                         if (regcomp(store.value_regex, value_regex,
 882                                         REG_EXTENDED)) {
 883                                 fprintf(stderr, "Invalid pattern: %s\n",
 884                                         value_regex);
 885                                 free(store.value_regex);
 886                                 ret = 6;
 887                                 goto out_free;
 888                         }
 889                 }
 890
 891                 store.offset[0] = 0;
 892                 store.state = START;
 893                 store.seen = 0;
 894
 895                 /*
 896                  * After this, store.offset will contain the *end* offset
 897                  * of the last match, or remain at 0 if no match was found.
 898                  * As a side effect, we make sure to transform only a valid
 899                  * existing config file.
 900                  */
 901                 if (git_config_from_file(store_aux, config_filename)) {
 902                         fprintf(stderr, "invalid config file\n");
 903                         free(store.key);
 904                         if (store.value_regex != NULL) {
 905                                 regfree(store.value_regex);
 906                                 free(store.value_regex);
 907                         }
 908                         ret = 3;
 909                         goto out_free;
 910                 }
 911
 912                 free(store.key);
 913                 if (store.value_regex != NULL) {
 914                         regfree(store.value_regex);
 915                         free(store.value_regex);
 916                 }
 917
 918                 /* if nothing to unset, or too many matches, error out */
 919                 if ((store.seen == 0 && value == NULL) ||
 920                                 (store.seen > 1 && multi_replace == 0)) {
 921                         ret = 5;
 922                         goto out_free;
 923                 }
 924
 925                 fstat(in_fd, &st);
 926                 contents_sz = xsize_t(st.st_size);
 927                 contents = xmmap(NULL, contents_sz, PROT_READ,
 928                         MAP_PRIVATE, in_fd, 0);
 929                 close(in_fd);
 930
 931                 if (store.seen == 0)
 932                         store.seen = 1;
 933
 934                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 935                         if (store.offset[i] == 0) {
 936                                 store.offset[i] = copy_end = contents_sz;
 937                         } else if (store.state != KEY_SEEN) {
 938                                 copy_end = store.offset[i];
 939                         } else
 940                                 copy_end = find_beginning_of_line(
 941                                         contents, contents_sz,
 942                                         store.offset[i]-2, &new_line);
 943
 944                         /* write the first part of the config */
 945                         if (copy_end > copy_begin) {
 946                                 if (write_in_full(fd, contents + copy_begin,
 947                                                   copy_end - copy_begin) <
 948                                     copy_end - copy_begin)
 949                                         goto write_err_out;
 950                                 if (new_line &&
 951                                     write_in_full(fd, "\n", 1) != 1)
 952                                         goto write_err_out;
 953                         }
 954                         copy_begin = store.offset[i];
 955                 }
 956
 957                 /* write the pair (value == NULL means unset) */
 958                 if (value != NULL) {
 959                         if (store.state == START) {
 960                                 if (!store_write_section(fd, key))
 961                                         goto write_err_out;
 962                         }
 963                         if (!store_write_pair(fd, key, value))
 964                                 goto write_err_out;
 965                 }
 966
 967                 /* write the rest of the config */
 968                 if (copy_begin < contents_sz)
 969                         if (write_in_full(fd, contents + copy_begin,
 970                                           contents_sz - copy_begin) <
 971                             contents_sz - copy_begin)
 972                                 goto write_err_out;
 973
 974                 munmap(contents, contents_sz);
 975         }
 976
 977         if (close(fd) || commit_lock_file(lock) < 0) {
 978                 fprintf(stderr, "Cannot commit config file!\n");
 979                 ret = 4;
 980                 goto out_free;
 981         }
 982
 983         /* fd is closed, so don't try to close it below. */
 984         fd = -1;
 985         /*
 986          * lock is committed, so don't try to roll it back below.
 987          * NOTE: Since lockfile.c keeps a linked list of all created
 988          * lock_file structures, it isn't safe to free(lock).  It's
 989          * better to just leave it hanging around.
 990          */
 991         lock = NULL;
 992         ret = 0;
 993
 994 out_free:
 995         if (0 <= fd)
 996                 close(fd);
 997         if (lock)
 998                 rollback_lock_file(lock);
 999         free(config_filename);
1000         return ret;
1001
1002 write_err_out:
1003         ret = write_error();
1004         goto out_free;
1005
1006 }
1007
1008 static int section_name_match (const char *buf, const char *name)
1009 {
1010         int i = 0, j = 0, dot = 0;
1011         for (; buf[i] && buf[i] != ']'; i++) {
1012                 if (!dot && isspace(buf[i])) {
1013                         dot = 1;
1014                         if (name[j++] != '.')
1015                                 break;
1016                         for (i++; isspace(buf[i]); i++)
1017                                 ; /* do nothing */
1018                         if (buf[i] != '"')
1019                                 break;
1020                         continue;
1021                 }
1022                 if (buf[i] == '\\' && dot)
1023                         i++;
1024                 else if (buf[i] == '"' && dot) {
1025                         for (i++; isspace(buf[i]); i++)
1026                                 ; /* do_nothing */
1027                         break;
1028                 }
1029                 if (buf[i] != name[j++])
1030                         break;
1031         }
1032         return (buf[i] == ']' && name[j] == 0);
1033 }
1034
1035 /* if new_name == NULL, the section is removed instead */
1036 int git_config_rename_section(const char *old_name, const char *new_name)
1037 {
1038         int ret = 0, remove = 0;
1039         char *config_filename;
1040         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1041         int out_fd;
1042         char buf[1024];
1043
1044         config_filename = getenv(CONFIG_ENVIRONMENT);
1045         if (!config_filename) {
1046                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1047                 if (!config_filename)
1048                         config_filename  = git_path("config");
1049         }
1050         config_filename = xstrdup(config_filename);
1051         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1052         if (out_fd < 0) {
1053                 ret = error("Could not lock config file!");
1054                 goto out;
1055         }
1056
1057         if (!(config_file = fopen(config_filename, "rb"))) {
1058                 /* no config file means nothing to rename, no error */
1059                 goto unlock_and_out;
1060         }
1061
1062         while (fgets(buf, sizeof(buf), config_file)) {
1063                 int i;
1064                 int length;
1065                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1066                         ; /* do nothing */
1067                 if (buf[i] == '[') {
1068                         /* it's a section */
1069                         if (section_name_match (&buf[i+1], old_name)) {
1070                                 ret++;
1071                                 if (new_name == NULL) {
1072                                         remove = 1;
1073                                         continue;
1074                                 }
1075                                 store.baselen = strlen(new_name);
1076                                 if (!store_write_section(out_fd, new_name)) {
1077                                         ret = write_error();
1078                                         goto out;
1079                                 }
1080                                 continue;
1081                         }
1082                         remove = 0;
1083                 }
1084                 if (remove)
1085                         continue;
1086                 length = strlen(buf);
1087                 if (write_in_full(out_fd, buf, length) != length) {
1088                         ret = write_error();
1089                         goto out;
1090                 }
1091         }
1092         fclose(config_file);
1093  unlock_and_out:
1094         if (close(out_fd) || commit_lock_file(lock) < 0)
1095                         ret = error("Cannot commit config file!");
1096  out:
1097         free(config_filename);
1098         return ret;
1099 }