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 config_file_eof;
  17 static int zlib_compression_seen;
  18
  19 static int get_next_char(void)
  20 {
  21         int c;
  22         FILE *f;
  23
  24         c = '\n';
  25         if ((f = config_file) != NULL) {
  26                 c = fgetc(f);
  27                 if (c == '\r') {
  28                         /* DOS like systems */
  29                         c = fgetc(f);
  30                         if (c != '\n') {
  31                                 ungetc(c, f);
  32                                 c = '\r';
  33                         }
  34                 }
  35                 if (c == '\n')
  36                         config_linenr++;
  37                 if (c == EOF) {
  38                         config_file_eof = 1;
  39                         c = '\n';
  40                 }
  41         }
  42         return c;
  43 }
  44
  45 static char *parse_value(void)
  46 {
  47         static char value[1024];
  48         int quote = 0, comment = 0, len = 0, space = 0;
  49
  50         for (;;) {
  51                 int c = get_next_char();
  52                 if (len >= sizeof(value))
  53                         return NULL;
  54                 if (c == '\n') {
  55                         if (quote)
  56                                 return NULL;
  57                         value[len] = 0;
  58                         return value;
  59                 }
  60                 if (comment)
  61                         continue;
  62                 if (isspace(c) && !quote) {
  63                         space = 1;
  64                         continue;
  65                 }
  66                 if (!quote) {
  67                         if (c == ';' || c == '#') {
  68                                 comment = 1;
  69                                 continue;
  70                         }
  71                 }
  72                 if (space) {
  73                         if (len)
  74                                 value[len++] = ' ';
  75                         space = 0;
  76                 }
  77                 if (c == '\\') {
  78                         c = get_next_char();
  79                         switch (c) {
  80                         case '\n':
  81                                 continue;
  82                         case 't':
  83                                 c = '\t';
  84                                 break;
  85                         case 'b':
  86                                 c = '\b';
  87                                 break;
  88                         case 'n':
  89                                 c = '\n';
  90                                 break;
  91                         /* Some characters escape as themselves */
  92                         case '\\': case '"':
  93                                 break;
  94                         /* Reject unknown escape sequences */
  95                         default:
  96                                 return NULL;
  97                         }
  98                         value[len++] = c;
  99                         continue;
 100                 }
 101                 if (c == '"') {
 102                         quote = 1-quote;
 103                         continue;
 104                 }
 105                 value[len++] = c;
 106         }
 107 }
 108
 109 static inline int iskeychar(int c)
 110 {
 111         return isalnum(c) || c == '-';
 112 }
 113
 114 static int get_value(config_fn_t fn, char *name, unsigned int len)
 115 {
 116         int c;
 117         char *value;
 118
 119         /* Get the full name */
 120         for (;;) {
 121                 c = get_next_char();
 122                 if (config_file_eof)
 123                         break;
 124                 if (!iskeychar(c))
 125                         break;
 126                 name[len++] = tolower(c);
 127                 if (len >= MAXNAME)
 128                         return -1;
 129         }
 130         name[len] = 0;
 131         while (c == ' ' || c == '\t')
 132                 c = get_next_char();
 133
 134         value = NULL;
 135         if (c != '\n') {
 136                 if (c != '=')
 137                         return -1;
 138                 value = parse_value();
 139                 if (!value)
 140                         return -1;
 141         }
 142         return fn(name, value);
 143 }
 144
 145 static int get_extended_base_var(char *name, int baselen, int c)
 146 {
 147         do {
 148                 if (c == '\n')
 149                         return -1;
 150                 c = get_next_char();
 151         } while (isspace(c));
 152
 153         /* We require the format to be '[base "extension"]' */
 154         if (c != '"')
 155                 return -1;
 156         name[baselen++] = '.';
 157
 158         for (;;) {
 159                 int c = get_next_char();
 160                 if (c == '\n')
 161                         return -1;
 162                 if (c == '"')
 163                         break;
 164                 if (c == '\\') {
 165                         c = get_next_char();
 166                         if (c == '\n')
 167                                 return -1;
 168                 }
 169                 name[baselen++] = c;
 170                 if (baselen > MAXNAME / 2)
 171                         return -1;
 172         }
 173
 174         /* Final ']' */
 175         if (get_next_char() != ']')
 176                 return -1;
 177         return baselen;
 178 }
 179
 180 static int get_base_var(char *name)
 181 {
 182         int baselen = 0;
 183
 184         for (;;) {
 185                 int c = get_next_char();
 186                 if (config_file_eof)
 187                         return -1;
 188                 if (c == ']')
 189                         return baselen;
 190                 if (isspace(c))
 191                         return get_extended_base_var(name, baselen, c);
 192                 if (!iskeychar(c) && c != '.')
 193                         return -1;
 194                 if (baselen > MAXNAME / 2)
 195                         return -1;
 196                 name[baselen++] = tolower(c);
 197         }
 198 }
 199
 200 static int git_parse_file(config_fn_t fn)
 201 {
 202         int comment = 0;
 203         int baselen = 0;
 204         static char var[MAXNAME];
 205
 206         for (;;) {
 207                 int c = get_next_char();
 208                 if (c == '\n') {
 209                         if (config_file_eof)
 210                                 return 0;
 211                         comment = 0;
 212                         continue;
 213                 }
 214                 if (comment || isspace(c))
 215                         continue;
 216                 if (c == '#' || c == ';') {
 217                         comment = 1;
 218                         continue;
 219                 }
 220                 if (c == '[') {
 221                         baselen = get_base_var(var);
 222                         if (baselen <= 0)
 223                                 break;
 224                         var[baselen++] = '.';
 225                         var[baselen] = 0;
 226                         continue;
 227                 }
 228                 if (!isalpha(c))
 229                         break;
 230                 var[baselen] = tolower(c);
 231                 if (get_value(fn, var, baselen+1) < 0)
 232                         break;
 233         }
 234         die("bad config file line %d in %s", config_linenr, config_file_name);
 235 }
 236
 237 static int parse_unit_factor(const char *end, unsigned long *val)
 238 {
 239         if (!*end)
 240                 return 1;
 241         else if (!strcasecmp(end, "k")) {
 242                 *val *= 1024;
 243                 return 1;
 244         }
 245         else if (!strcasecmp(end, "m")) {
 246                 *val *= 1024 * 1024;
 247                 return 1;
 248         }
 249         else if (!strcasecmp(end, "g")) {
 250                 *val *= 1024 * 1024 * 1024;
 251                 return 1;
 252         }
 253         return 0;
 254 }
 255
 256 int git_parse_long(const char *value, long *ret)
 257 {
 258         if (value && *value) {
 259                 char *end;
 260                 long val = strtol(value, &end, 0);
 261                 unsigned long factor = 1;
 262                 if (!parse_unit_factor(end, &factor))
 263                         return 0;
 264                 *ret = val * factor;
 265                 return 1;
 266         }
 267         return 0;
 268 }
 269
 270 int git_parse_ulong(const char *value, unsigned long *ret)
 271 {
 272         if (value && *value) {
 273                 char *end;
 274                 unsigned long val = strtoul(value, &end, 0);
 275                 if (!parse_unit_factor(end, &val))
 276                         return 0;
 277                 *ret = val;
 278                 return 1;
 279         }
 280         return 0;
 281 }
 282
 283 int git_config_int(const char *name, const char *value)
 284 {
 285         long ret;
 286         if (!git_parse_long(value, &ret))
 287                 die("bad config value for '%s' in %s", name, config_file_name);
 288         return ret;
 289 }
 290
 291 unsigned long git_config_ulong(const char *name, const char *value)
 292 {
 293         unsigned long ret;
 294         if (!git_parse_ulong(value, &ret))
 295                 die("bad config value for '%s' in %s", name, config_file_name);
 296         return ret;
 297 }
 298
 299 int git_config_bool(const char *name, const char *value)
 300 {
 301         if (!value)
 302                 return 1;
 303         if (!*value)
 304                 return 0;
 305         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 306                 return 1;
 307         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 308                 return 0;
 309         return git_config_int(name, value) != 0;
 310 }
 311
 312 int git_config_string(const char **dest, const char *var, const char *value)
 313 {
 314         if (!value)
 315                 return config_error_nonbool(var);
 316         *dest = xstrdup(value);
 317         return 0;
 318 }
 319
 320 int git_default_config(const char *var, const char *value)
 321 {
 322         /* This needs a better name */
 323         if (!strcmp(var, "core.filemode")) {
 324                 trust_executable_bit = git_config_bool(var, value);
 325                 return 0;
 326         }
 327
 328         if (!strcmp(var, "core.quotepath")) {
 329                 quote_path_fully = git_config_bool(var, value);
 330                 return 0;
 331         }
 332
 333         if (!strcmp(var, "core.symlinks")) {
 334                 has_symlinks = git_config_bool(var, value);
 335                 return 0;
 336         }
 337
 338         if (!strcmp(var, "core.bare")) {
 339                 is_bare_repository_cfg = git_config_bool(var, value);
 340                 return 0;
 341         }
 342
 343         if (!strcmp(var, "core.ignorestat")) {
 344                 assume_unchanged = git_config_bool(var, value);
 345                 return 0;
 346         }
 347
 348         if (!strcmp(var, "core.prefersymlinkrefs")) {
 349                 prefer_symlink_refs = git_config_bool(var, value);
 350                 return 0;
 351         }
 352
 353         if (!strcmp(var, "core.logallrefupdates")) {
 354                 log_all_ref_updates = git_config_bool(var, value);
 355                 return 0;
 356         }
 357
 358         if (!strcmp(var, "core.warnambiguousrefs")) {
 359                 warn_ambiguous_refs = git_config_bool(var, value);
 360                 return 0;
 361         }
 362
 363         if (!strcmp(var, "core.loosecompression")) {
 364                 int level = git_config_int(var, value);
 365                 if (level == -1)
 366                         level = Z_DEFAULT_COMPRESSION;
 367                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 368                         die("bad zlib compression level %d", level);
 369                 zlib_compression_level = level;
 370                 zlib_compression_seen = 1;
 371                 return 0;
 372         }
 373
 374         if (!strcmp(var, "core.compression")) {
 375                 int level = git_config_int(var, value);
 376                 if (level == -1)
 377                         level = Z_DEFAULT_COMPRESSION;
 378                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 379                         die("bad zlib compression level %d", level);
 380                 core_compression_level = level;
 381                 core_compression_seen = 1;
 382                 if (!zlib_compression_seen)
 383                         zlib_compression_level = level;
 384                 return 0;
 385         }
 386
 387         if (!strcmp(var, "core.packedgitwindowsize")) {
 388                 int pgsz_x2 = getpagesize() * 2;
 389                 packed_git_window_size = git_config_int(var, value);
 390
 391                 /* This value must be multiple of (pagesize * 2) */
 392                 packed_git_window_size /= pgsz_x2;
 393                 if (packed_git_window_size < 1)
 394                         packed_git_window_size = 1;
 395                 packed_git_window_size *= pgsz_x2;
 396                 return 0;
 397         }
 398
 399         if (!strcmp(var, "core.packedgitlimit")) {
 400                 packed_git_limit = git_config_int(var, value);
 401                 return 0;
 402         }
 403
 404         if (!strcmp(var, "core.deltabasecachelimit")) {
 405                 delta_base_cache_limit = git_config_int(var, value);
 406                 return 0;
 407         }
 408
 409         if (!strcmp(var, "core.autocrlf")) {
 410                 if (value && !strcasecmp(value, "input")) {
 411                         auto_crlf = -1;
 412                         return 0;
 413                 }
 414                 auto_crlf = git_config_bool(var, value);
 415                 return 0;
 416         }
 417
 418         if (!strcmp(var, "user.name")) {
 419                 if (!value)
 420                         return config_error_nonbool(var);
 421                 strlcpy(git_default_name, value, sizeof(git_default_name));
 422                 return 0;
 423         }
 424
 425         if (!strcmp(var, "user.email")) {
 426                 if (!value)
 427                         return config_error_nonbool(var);
 428                 strlcpy(git_default_email, value, sizeof(git_default_email));
 429                 return 0;
 430         }
 431
 432         if (!strcmp(var, "i18n.commitencoding"))
 433                 return git_config_string(&git_commit_encoding, var, value);
 434
 435         if (!strcmp(var, "i18n.logoutputencoding"))
 436                 return git_config_string(&git_log_output_encoding, var, value);
 437
 438         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 439                 pager_use_color = git_config_bool(var,value);
 440                 return 0;
 441         }
 442
 443         if (!strcmp(var, "core.pager"))
 444                 return git_config_string(&pager_program, var, value);
 445
 446         if (!strcmp(var, "core.editor"))
 447                 return git_config_string(&editor_program, var, value);
 448
 449         if (!strcmp(var, "core.excludesfile"))
 450                 return git_config_string(&excludes_file, var, value);
 451
 452         if (!strcmp(var, "core.whitespace")) {
 453                 if (!value)
 454                         return config_error_nonbool(var);
 455                 whitespace_rule_cfg = parse_whitespace_rule(value);
 456                 return 0;
 457         }
 458
 459         /* Add other config variables here and to Documentation/config.txt. */
 460         return 0;
 461 }
 462
 463 int git_config_from_file(config_fn_t fn, const char *filename)
 464 {
 465         int ret;
 466         FILE *f = fopen(filename, "r");
 467
 468         ret = -1;
 469         if (f) {
 470                 config_file = f;
 471                 config_file_name = filename;
 472                 config_linenr = 1;
 473                 config_file_eof = 0;
 474                 ret = git_parse_file(fn);
 475                 fclose(f);
 476                 config_file_name = NULL;
 477         }
 478         return ret;
 479 }
 480
 481 const char *git_etc_gitconfig(void)
 482 {
 483         static const char *system_wide;
 484         if (!system_wide) {
 485                 system_wide = ETC_GITCONFIG;
 486                 if (!is_absolute_path(system_wide)) {
 487                         /* interpret path relative to exec-dir */
 488                         struct strbuf d = STRBUF_INIT;
 489                         strbuf_addf(&d, "%s/%s", git_exec_path(), system_wide);
 490                         system_wide = strbuf_detach(&d, NULL);
 491                 }
 492         }
 493         return system_wide;
 494 }
 495
 496 int git_config(config_fn_t fn)
 497 {
 498         int ret = 0;
 499         char *repo_config = NULL;
 500         const char *home = NULL, *filename;
 501
 502         /* $GIT_CONFIG makes git read _only_ the given config file,
 503          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 504          * global config file, the same way it would the per-repository
 505          * config file otherwise. */
 506         filename = getenv(CONFIG_ENVIRONMENT);
 507         if (!filename) {
 508                 if (!access(git_etc_gitconfig(), R_OK))
 509                         ret += git_config_from_file(fn, git_etc_gitconfig());
 510                 home = getenv("HOME");
 511                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 512                 if (!filename)
 513                         filename = repo_config = xstrdup(git_path("config"));
 514         }
 515
 516         if (home) {
 517                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 518                 if (!access(user_config, R_OK))
 519                         ret = git_config_from_file(fn, user_config);
 520                 free(user_config);
 521         }
 522
 523         ret += git_config_from_file(fn, filename);
 524         free(repo_config);
 525         return ret;
 526 }
 527
 528 /*
 529  * Find all the stuff for git_config_set() below.
 530  */
 531
 532 #define MAX_MATCHES 512
 533
 534 static struct {
 535         int baselen;
 536         char* key;
 537         int do_not_match;
 538         regex_t* value_regex;
 539         int multi_replace;
 540         size_t offset[MAX_MATCHES];
 541         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 542         int seen;
 543 } store;
 544
 545 static int matches(const char* key, const char* value)
 546 {
 547         return !strcmp(key, store.key) &&
 548                 (store.value_regex == NULL ||
 549                  (store.do_not_match ^
 550                   !regexec(store.value_regex, value, 0, NULL, 0)));
 551 }
 552
 553 static int store_aux(const char* key, const char* value)
 554 {
 555         const char *ep;
 556         size_t section_len;
 557
 558         switch (store.state) {
 559         case KEY_SEEN:
 560                 if (matches(key, value)) {
 561                         if (store.seen == 1 && store.multi_replace == 0) {
 562                                 fprintf(stderr,
 563                                         "Warning: %s has multiple values\n",
 564                                         key);
 565                         } else if (store.seen >= MAX_MATCHES) {
 566                                 fprintf(stderr, "Too many matches\n");
 567                                 return 1;
 568                         }
 569
 570                         store.offset[store.seen] = ftell(config_file);
 571                         store.seen++;
 572                 }
 573                 break;
 574         case SECTION_SEEN:
 575                 /*
 576                  * What we are looking for is in store.key (both
 577                  * section and var), and its section part is baselen
 578                  * long.  We found key (again, both section and var).
 579                  * We would want to know if this key is in the same
 580                  * section as what we are looking for.  We already
 581                  * know we are in the same section as what should
 582                  * hold store.key.
 583                  */
 584                 ep = strrchr(key, '.');
 585                 section_len = ep - key;
 586
 587                 if ((section_len != store.baselen) ||
 588                     memcmp(key, store.key, section_len+1)) {
 589                         store.state = SECTION_END_SEEN;
 590                         break;
 591                 }
 592
 593                 /*
 594                  * Do not increment matches: this is no match, but we
 595                  * just made sure we are in the desired section.
 596                  */
 597                 store.offset[store.seen] = ftell(config_file);
 598                 /* fallthru */
 599         case SECTION_END_SEEN:
 600         case START:
 601                 if (matches(key, value)) {
 602                         store.offset[store.seen] = ftell(config_file);
 603                         store.state = KEY_SEEN;
 604                         store.seen++;
 605                 } else {
 606                         if (strrchr(key, '.') - key == store.baselen &&
 607                               !strncmp(key, store.key, store.baselen)) {
 608                                         store.state = SECTION_SEEN;
 609                                         store.offset[store.seen] = ftell(config_file);
 610                         }
 611                 }
 612         }
 613         return 0;
 614 }
 615
 616 static int write_error(void)
 617 {
 618         fprintf(stderr, "Failed to write new configuration file\n");
 619
 620         /* Same error code as "failed to rename". */
 621         return 4;
 622 }
 623
 624 static int store_write_section(int fd, const char* key)
 625 {
 626         const char *dot;
 627         int i, success;
 628         struct strbuf sb;
 629
 630         strbuf_init(&sb, 0);
 631         dot = memchr(key, '.', store.baselen);
 632         if (dot) {
 633                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 634                 for (i = dot - key + 1; i < store.baselen; i++) {
 635                         if (key[i] == '"')
 636                                 strbuf_addch(&sb, '\\');
 637                         strbuf_addch(&sb, key[i]);
 638                 }
 639                 strbuf_addstr(&sb, "\"]\n");
 640         } else {
 641                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 642         }
 643
 644         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 645         strbuf_release(&sb);
 646
 647         return success;
 648 }
 649
 650 static int store_write_pair(int fd, const char* key, const char* value)
 651 {
 652         int i, success;
 653         int length = strlen(key + store.baselen + 1);
 654         const char *quote = "";
 655         struct strbuf sb;
 656
 657         /*
 658          * Check to see if the value needs to be surrounded with a dq pair.
 659          * Note that problematic characters are always backslash-quoted; this
 660          * check is about not losing leading or trailing SP and strings that
 661          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 662          * configuration parser.
 663          */
 664         if (value[0] == ' ')
 665                 quote = "\"";
 666         for (i = 0; value[i]; i++)
 667                 if (value[i] == ';' || value[i] == '#')
 668                         quote = "\"";
 669         if (i && value[i - 1] == ' ')
 670                 quote = "\"";
 671
 672         strbuf_init(&sb, 0);
 673         strbuf_addf(&sb, "\t%.*s = %s",
 674                     length, key + store.baselen + 1, quote);
 675
 676         for (i = 0; value[i]; i++)
 677                 switch (value[i]) {
 678                 case '\n':
 679                         strbuf_addstr(&sb, "\\n");
 680                         break;
 681                 case '\t':
 682                         strbuf_addstr(&sb, "\\t");
 683                         break;
 684                 case '"':
 685                 case '\\':
 686                         strbuf_addch(&sb, '\\');
 687                 default:
 688                         strbuf_addch(&sb, value[i]);
 689                         break;
 690                 }
 691         strbuf_addf(&sb, "%s\n", quote);
 692
 693         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 694         strbuf_release(&sb);
 695
 696         return success;
 697 }
 698
 699 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 700         size_t offset_, int* found_bracket)
 701 {
 702         size_t equal_offset = size, bracket_offset = size;
 703         ssize_t offset;
 704
 705 contline:
 706         for (offset = offset_-2; offset > 0
 707                         && contents[offset] != '\n'; offset--)
 708                 switch (contents[offset]) {
 709                         case '=': equal_offset = offset; break;
 710                         case ']': bracket_offset = offset; break;
 711                 }
 712         if (offset > 0 && contents[offset-1] == '\\') {
 713                 offset_ = offset;
 714                 goto contline;
 715         }
 716         if (bracket_offset < equal_offset) {
 717                 *found_bracket = 1;
 718                 offset = bracket_offset+1;
 719         } else
 720                 offset++;
 721
 722         return offset;
 723 }
 724
 725 int git_config_set(const char* key, const char* value)
 726 {
 727         return git_config_set_multivar(key, value, NULL, 0);
 728 }
 729
 730 /*
 731  * If value==NULL, unset in (remove from) config,
 732  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 733  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 734  *     else all matching key/values (regardless how many) are removed,
 735  *     before the new pair is written.
 736  *
 737  * Returns 0 on success.
 738  *
 739  * This function does this:
 740  *
 741  * - it locks the config file by creating ".git/config.lock"
 742  *
 743  * - it then parses the config using store_aux() as validator to find
 744  *   the position on the key/value pair to replace. If it is to be unset,
 745  *   it must be found exactly once.
 746  *
 747  * - the config file is mmap()ed and the part before the match (if any) is
 748  *   written to the lock file, then the changed part and the rest.
 749  *
 750  * - the config file is removed and the lock file rename()d to it.
 751  *
 752  */
 753 int git_config_set_multivar(const char* key, const char* value,
 754         const char* value_regex, int multi_replace)
 755 {
 756         int i, dot;
 757         int fd = -1, in_fd;
 758         int ret;
 759         char* config_filename;
 760         struct lock_file *lock = NULL;
 761         const char* last_dot = strrchr(key, '.');
 762
 763         config_filename = getenv(CONFIG_ENVIRONMENT);
 764         if (!config_filename) {
 765                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 766                 if (!config_filename)
 767                         config_filename  = git_path("config");
 768         }
 769         config_filename = xstrdup(config_filename);
 770
 771         /*
 772          * Since "key" actually contains the section name and the real
 773          * key name separated by a dot, we have to know where the dot is.
 774          */
 775
 776         if (last_dot == NULL) {
 777                 fprintf(stderr, "key does not contain a section: %s\n", key);
 778                 ret = 2;
 779                 goto out_free;
 780         }
 781         store.baselen = last_dot - key;
 782
 783         store.multi_replace = multi_replace;
 784
 785         /*
 786          * Validate the key and while at it, lower case it for matching.
 787          */
 788         store.key = xmalloc(strlen(key) + 1);
 789         dot = 0;
 790         for (i = 0; key[i]; i++) {
 791                 unsigned char c = key[i];
 792                 if (c == '.')
 793                         dot = 1;
 794                 /* Leave the extended basename untouched.. */
 795                 if (!dot || i > store.baselen) {
 796                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 797                                 fprintf(stderr, "invalid key: %s\n", key);
 798                                 free(store.key);
 799                                 ret = 1;
 800                                 goto out_free;
 801                         }
 802                         c = tolower(c);
 803                 } else if (c == '\n') {
 804                         fprintf(stderr, "invalid key (newline): %s\n", key);
 805                         free(store.key);
 806                         ret = 1;
 807                         goto out_free;
 808                 }
 809                 store.key[i] = c;
 810         }
 811         store.key[i] = 0;
 812
 813         /*
 814          * The lock serves a purpose in addition to locking: the new
 815          * contents of .git/config will be written into it.
 816          */
 817         lock = xcalloc(sizeof(struct lock_file), 1);
 818         fd = hold_lock_file_for_update(lock, config_filename, 0);
 819         if (fd < 0) {
 820                 fprintf(stderr, "could not lock config file\n");
 821                 free(store.key);
 822                 ret = -1;
 823                 goto out_free;
 824         }
 825
 826         /*
 827          * If .git/config does not exist yet, write a minimal version.
 828          */
 829         in_fd = open(config_filename, O_RDONLY);
 830         if ( in_fd < 0 ) {
 831                 free(store.key);
 832
 833                 if ( ENOENT != errno ) {
 834                         error("opening %s: %s", config_filename,
 835                               strerror(errno));
 836                         ret = 3; /* same as "invalid config file" */
 837                         goto out_free;
 838                 }
 839                 /* if nothing to unset, error out */
 840                 if (value == NULL) {
 841                         ret = 5;
 842                         goto out_free;
 843                 }
 844
 845                 store.key = (char*)key;
 846                 if (!store_write_section(fd, key) ||
 847                     !store_write_pair(fd, key, value))
 848                         goto write_err_out;
 849         } else {
 850                 struct stat st;
 851                 char* contents;
 852                 size_t contents_sz, copy_begin, copy_end;
 853                 int i, new_line = 0;
 854
 855                 if (value_regex == NULL)
 856                         store.value_regex = NULL;
 857                 else {
 858                         if (value_regex[0] == '!') {
 859                                 store.do_not_match = 1;
 860                                 value_regex++;
 861                         } else
 862                                 store.do_not_match = 0;
 863
 864                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 865                         if (regcomp(store.value_regex, value_regex,
 866                                         REG_EXTENDED)) {
 867                                 fprintf(stderr, "Invalid pattern: %s\n",
 868                                         value_regex);
 869                                 free(store.value_regex);
 870                                 ret = 6;
 871                                 goto out_free;
 872                         }
 873                 }
 874
 875                 store.offset[0] = 0;
 876                 store.state = START;
 877                 store.seen = 0;
 878
 879                 /*
 880                  * After this, store.offset will contain the *end* offset
 881                  * of the last match, or remain at 0 if no match was found.
 882                  * As a side effect, we make sure to transform only a valid
 883                  * existing config file.
 884                  */
 885                 if (git_config_from_file(store_aux, config_filename)) {
 886                         fprintf(stderr, "invalid config file\n");
 887                         free(store.key);
 888                         if (store.value_regex != NULL) {
 889                                 regfree(store.value_regex);
 890                                 free(store.value_regex);
 891                         }
 892                         ret = 3;
 893                         goto out_free;
 894                 }
 895
 896                 free(store.key);
 897                 if (store.value_regex != NULL) {
 898                         regfree(store.value_regex);
 899                         free(store.value_regex);
 900                 }
 901
 902                 /* if nothing to unset, or too many matches, error out */
 903                 if ((store.seen == 0 && value == NULL) ||
 904                                 (store.seen > 1 && multi_replace == 0)) {
 905                         ret = 5;
 906                         goto out_free;
 907                 }
 908
 909                 fstat(in_fd, &st);
 910                 contents_sz = xsize_t(st.st_size);
 911                 contents = xmmap(NULL, contents_sz, PROT_READ,
 912                         MAP_PRIVATE, in_fd, 0);
 913                 close(in_fd);
 914
 915                 if (store.seen == 0)
 916                         store.seen = 1;
 917
 918                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 919                         if (store.offset[i] == 0) {
 920                                 store.offset[i] = copy_end = contents_sz;
 921                         } else if (store.state != KEY_SEEN) {
 922                                 copy_end = store.offset[i];
 923                         } else
 924                                 copy_end = find_beginning_of_line(
 925                                         contents, contents_sz,
 926                                         store.offset[i]-2, &new_line);
 927
 928                         if (copy_end > 0 && contents[copy_end-1] != '\n')
 929                                 new_line = 1;
 930
 931                         /* write the first part of the config */
 932                         if (copy_end > copy_begin) {
 933                                 if (write_in_full(fd, contents + copy_begin,
 934                                                   copy_end - copy_begin) <
 935                                     copy_end - copy_begin)
 936                                         goto write_err_out;
 937                                 if (new_line &&
 938                                     write_in_full(fd, "\n", 1) != 1)
 939                                         goto write_err_out;
 940                         }
 941                         copy_begin = store.offset[i];
 942                 }
 943
 944                 /* write the pair (value == NULL means unset) */
 945                 if (value != NULL) {
 946                         if (store.state == START) {
 947                                 if (!store_write_section(fd, key))
 948                                         goto write_err_out;
 949                         }
 950                         if (!store_write_pair(fd, key, value))
 951                                 goto write_err_out;
 952                 }
 953
 954                 /* write the rest of the config */
 955                 if (copy_begin < contents_sz)
 956                         if (write_in_full(fd, contents + copy_begin,
 957                                           contents_sz - copy_begin) <
 958                             contents_sz - copy_begin)
 959                                 goto write_err_out;
 960
 961                 munmap(contents, contents_sz);
 962         }
 963
 964         if (commit_lock_file(lock) < 0) {
 965                 fprintf(stderr, "Cannot commit config file!\n");
 966                 ret = 4;
 967                 goto out_free;
 968         }
 969
 970         /*
 971          * lock is committed, so don't try to roll it back below.
 972          * NOTE: Since lockfile.c keeps a linked list of all created
 973          * lock_file structures, it isn't safe to free(lock).  It's
 974          * better to just leave it hanging around.
 975          */
 976         lock = NULL;
 977         ret = 0;
 978
 979 out_free:
 980         if (lock)
 981                 rollback_lock_file(lock);
 982         free(config_filename);
 983         return ret;
 984
 985 write_err_out:
 986         ret = write_error();
 987         goto out_free;
 988
 989 }
 990
 991 static int section_name_match (const char *buf, const char *name)
 992 {
 993         int i = 0, j = 0, dot = 0;
 994         for (; buf[i] && buf[i] != ']'; i++) {
 995                 if (!dot && isspace(buf[i])) {
 996                         dot = 1;
 997                         if (name[j++] != '.')
 998                                 break;
 999                         for (i++; isspace(buf[i]); i++)
1000                                 ; /* do nothing */
1001                         if (buf[i] != '"')
1002                                 break;
1003                         continue;
1004                 }
1005                 if (buf[i] == '\\' && dot)
1006                         i++;
1007                 else if (buf[i] == '"' && dot) {
1008                         for (i++; isspace(buf[i]); i++)
1009                                 ; /* do_nothing */
1010                         break;
1011                 }
1012                 if (buf[i] != name[j++])
1013                         break;
1014         }
1015         return (buf[i] == ']' && name[j] == 0);
1016 }
1017
1018 /* if new_name == NULL, the section is removed instead */
1019 int git_config_rename_section(const char *old_name, const char *new_name)
1020 {
1021         int ret = 0, remove = 0;
1022         char *config_filename;
1023         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1024         int out_fd;
1025         char buf[1024];
1026
1027         config_filename = getenv(CONFIG_ENVIRONMENT);
1028         if (!config_filename) {
1029                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1030                 if (!config_filename)
1031                         config_filename  = git_path("config");
1032         }
1033         config_filename = xstrdup(config_filename);
1034         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1035         if (out_fd < 0) {
1036                 ret = error("Could not lock config file!");
1037                 goto out;
1038         }
1039
1040         if (!(config_file = fopen(config_filename, "rb"))) {
1041                 /* no config file means nothing to rename, no error */
1042                 goto unlock_and_out;
1043         }
1044
1045         while (fgets(buf, sizeof(buf), config_file)) {
1046                 int i;
1047                 int length;
1048                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1049                         ; /* do nothing */
1050                 if (buf[i] == '[') {
1051                         /* it's a section */
1052                         if (section_name_match (&buf[i+1], old_name)) {
1053                                 ret++;
1054                                 if (new_name == NULL) {
1055                                         remove = 1;
1056                                         continue;
1057                                 }
1058                                 store.baselen = strlen(new_name);
1059                                 if (!store_write_section(out_fd, new_name)) {
1060                                         ret = write_error();
1061                                         goto out;
1062                                 }
1063                                 continue;
1064                         }
1065                         remove = 0;
1066                 }
1067                 if (remove)
1068                         continue;
1069                 length = strlen(buf);
1070                 if (write_in_full(out_fd, buf, length) != length) {
1071                         ret = write_error();
1072                         goto out;
1073                 }
1074         }
1075         fclose(config_file);
1076  unlock_and_out:
1077         if (commit_lock_file(lock) < 0)
1078                         ret = error("Cannot commit config file!");
1079  out:
1080         free(config_filename);
1081         return ret;
1082 }
1083
1084 /*
1085  * Call this to report error for your variable that should not
1086  * get a boolean value (i.e. "[my] var" means "true").
1087  */
1088 int config_error_nonbool(const char *var)
1089 {
1090         return error("Missing value for '%s'", var);
1091 }