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 static void die_bad_config(const char *name)
 284 {
 285         if (config_file_name)
 286                 die("bad config value for '%s' in %s", name, config_file_name);
 287         die("bad config value for '%s'", name);
 288 }
 289
 290 int git_config_int(const char *name, const char *value)
 291 {
 292         long ret;
 293         if (!git_parse_long(value, &ret))
 294                 die_bad_config(name);
 295         return ret;
 296 }
 297
 298 unsigned long git_config_ulong(const char *name, const char *value)
 299 {
 300         unsigned long ret;
 301         if (!git_parse_ulong(value, &ret))
 302                 die_bad_config(name);
 303         return ret;
 304 }
 305
 306 int git_config_bool(const char *name, const char *value)
 307 {
 308         if (!value)
 309                 return 1;
 310         if (!*value)
 311                 return 0;
 312         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 313                 return 1;
 314         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 315                 return 0;
 316         return git_config_int(name, value) != 0;
 317 }
 318
 319 int git_config_string(const char **dest, const char *var, const char *value)
 320 {
 321         if (!value)
 322                 return config_error_nonbool(var);
 323         *dest = xstrdup(value);
 324         return 0;
 325 }
 326
 327 int git_default_config(const char *var, const char *value)
 328 {
 329         /* This needs a better name */
 330         if (!strcmp(var, "core.filemode")) {
 331                 trust_executable_bit = git_config_bool(var, value);
 332                 return 0;
 333         }
 334
 335         if (!strcmp(var, "core.quotepath")) {
 336                 quote_path_fully = git_config_bool(var, value);
 337                 return 0;
 338         }
 339
 340         if (!strcmp(var, "core.symlinks")) {
 341                 has_symlinks = git_config_bool(var, value);
 342                 return 0;
 343         }
 344
 345         if (!strcmp(var, "core.bare")) {
 346                 is_bare_repository_cfg = git_config_bool(var, value);
 347                 return 0;
 348         }
 349
 350         if (!strcmp(var, "core.ignorestat")) {
 351                 assume_unchanged = git_config_bool(var, value);
 352                 return 0;
 353         }
 354
 355         if (!strcmp(var, "core.prefersymlinkrefs")) {
 356                 prefer_symlink_refs = git_config_bool(var, value);
 357                 return 0;
 358         }
 359
 360         if (!strcmp(var, "core.logallrefupdates")) {
 361                 log_all_ref_updates = git_config_bool(var, value);
 362                 return 0;
 363         }
 364
 365         if (!strcmp(var, "core.warnambiguousrefs")) {
 366                 warn_ambiguous_refs = git_config_bool(var, value);
 367                 return 0;
 368         }
 369
 370         if (!strcmp(var, "core.loosecompression")) {
 371                 int level = git_config_int(var, value);
 372                 if (level == -1)
 373                         level = Z_DEFAULT_COMPRESSION;
 374                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 375                         die("bad zlib compression level %d", level);
 376                 zlib_compression_level = level;
 377                 zlib_compression_seen = 1;
 378                 return 0;
 379         }
 380
 381         if (!strcmp(var, "core.compression")) {
 382                 int level = git_config_int(var, value);
 383                 if (level == -1)
 384                         level = Z_DEFAULT_COMPRESSION;
 385                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 386                         die("bad zlib compression level %d", level);
 387                 core_compression_level = level;
 388                 core_compression_seen = 1;
 389                 if (!zlib_compression_seen)
 390                         zlib_compression_level = level;
 391                 return 0;
 392         }
 393
 394         if (!strcmp(var, "core.packedgitwindowsize")) {
 395                 int pgsz_x2 = getpagesize() * 2;
 396                 packed_git_window_size = git_config_int(var, value);
 397
 398                 /* This value must be multiple of (pagesize * 2) */
 399                 packed_git_window_size /= pgsz_x2;
 400                 if (packed_git_window_size < 1)
 401                         packed_git_window_size = 1;
 402                 packed_git_window_size *= pgsz_x2;
 403                 return 0;
 404         }
 405
 406         if (!strcmp(var, "core.packedgitlimit")) {
 407                 packed_git_limit = git_config_int(var, value);
 408                 return 0;
 409         }
 410
 411         if (!strcmp(var, "core.deltabasecachelimit")) {
 412                 delta_base_cache_limit = git_config_int(var, value);
 413                 return 0;
 414         }
 415
 416         if (!strcmp(var, "core.autocrlf")) {
 417                 if (value && !strcasecmp(value, "input")) {
 418                         auto_crlf = -1;
 419                         return 0;
 420                 }
 421                 auto_crlf = git_config_bool(var, value);
 422                 return 0;
 423         }
 424
 425         if (!strcmp(var, "core.safecrlf")) {
 426                 if (value && !strcasecmp(value, "warn")) {
 427                         safe_crlf = SAFE_CRLF_WARN;
 428                         return 0;
 429                 }
 430                 safe_crlf = git_config_bool(var, value);
 431                 return 0;
 432         }
 433
 434         if (!strcmp(var, "user.name")) {
 435                 if (!value)
 436                         return config_error_nonbool(var);
 437                 strlcpy(git_default_name, value, sizeof(git_default_name));
 438                 return 0;
 439         }
 440
 441         if (!strcmp(var, "user.email")) {
 442                 if (!value)
 443                         return config_error_nonbool(var);
 444                 strlcpy(git_default_email, value, sizeof(git_default_email));
 445                 return 0;
 446         }
 447
 448         if (!strcmp(var, "i18n.commitencoding"))
 449                 return git_config_string(&git_commit_encoding, var, value);
 450
 451         if (!strcmp(var, "i18n.logoutputencoding"))
 452                 return git_config_string(&git_log_output_encoding, var, value);
 453
 454         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 455                 pager_use_color = git_config_bool(var,value);
 456                 return 0;
 457         }
 458
 459         if (!strcmp(var, "core.pager"))
 460                 return git_config_string(&pager_program, var, value);
 461
 462         if (!strcmp(var, "core.editor"))
 463                 return git_config_string(&editor_program, var, value);
 464
 465         if (!strcmp(var, "core.excludesfile"))
 466                 return git_config_string(&excludes_file, var, value);
 467
 468         if (!strcmp(var, "core.whitespace")) {
 469                 if (!value)
 470                         return config_error_nonbool(var);
 471                 whitespace_rule_cfg = parse_whitespace_rule(value);
 472                 return 0;
 473         }
 474
 475         /* Add other config variables here and to Documentation/config.txt. */
 476         return 0;
 477 }
 478
 479 int git_config_from_file(config_fn_t fn, const char *filename)
 480 {
 481         int ret;
 482         FILE *f = fopen(filename, "r");
 483
 484         ret = -1;
 485         if (f) {
 486                 config_file = f;
 487                 config_file_name = filename;
 488                 config_linenr = 1;
 489                 config_file_eof = 0;
 490                 ret = git_parse_file(fn);
 491                 fclose(f);
 492                 config_file_name = NULL;
 493         }
 494         return ret;
 495 }
 496
 497 const char *git_etc_gitconfig(void)
 498 {
 499         static const char *system_wide;
 500         if (!system_wide) {
 501                 system_wide = ETC_GITCONFIG;
 502                 if (!is_absolute_path(system_wide)) {
 503                         /* interpret path relative to exec-dir */
 504                         struct strbuf d = STRBUF_INIT;
 505                         strbuf_addf(&d, "%s/%s", git_exec_path(), system_wide);
 506                         system_wide = strbuf_detach(&d, NULL);
 507                 }
 508         }
 509         return system_wide;
 510 }
 511
 512 int git_env_bool(const char *k, int def)
 513 {
 514         const char *v = getenv(k);
 515         return v ? git_config_bool(k, v) : def;
 516 }
 517
 518 int git_config_system(void)
 519 {
 520         return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
 521 }
 522
 523 int git_config_global(void)
 524 {
 525         return !git_env_bool("GIT_CONFIG_NOGLOBAL", 0);
 526 }
 527
 528 int git_config(config_fn_t fn)
 529 {
 530         int ret = 0;
 531         char *repo_config = NULL;
 532         const char *home = NULL, *filename;
 533
 534         /* $GIT_CONFIG makes git read _only_ the given config file,
 535          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 536          * global config file, the same way it would the per-repository
 537          * config file otherwise. */
 538         filename = getenv(CONFIG_ENVIRONMENT);
 539         if (!filename) {
 540                 if (git_config_system() && !access(git_etc_gitconfig(), R_OK))
 541                         ret += git_config_from_file(fn, git_etc_gitconfig());
 542                 home = getenv("HOME");
 543                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 544                 if (!filename)
 545                         filename = repo_config = xstrdup(git_path("config"));
 546         }
 547
 548         if (git_config_global() && home) {
 549                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 550                 if (!access(user_config, R_OK))
 551                         ret = git_config_from_file(fn, user_config);
 552                 free(user_config);
 553         }
 554
 555         ret += git_config_from_file(fn, filename);
 556         free(repo_config);
 557         return ret;
 558 }
 559
 560 /*
 561  * Find all the stuff for git_config_set() below.
 562  */
 563
 564 #define MAX_MATCHES 512
 565
 566 static struct {
 567         int baselen;
 568         char* key;
 569         int do_not_match;
 570         regex_t* value_regex;
 571         int multi_replace;
 572         size_t offset[MAX_MATCHES];
 573         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 574         int seen;
 575 } store;
 576
 577 static int matches(const char* key, const char* value)
 578 {
 579         return !strcmp(key, store.key) &&
 580                 (store.value_regex == NULL ||
 581                  (store.do_not_match ^
 582                   !regexec(store.value_regex, value, 0, NULL, 0)));
 583 }
 584
 585 static int store_aux(const char* key, const char* value)
 586 {
 587         const char *ep;
 588         size_t section_len;
 589
 590         switch (store.state) {
 591         case KEY_SEEN:
 592                 if (matches(key, value)) {
 593                         if (store.seen == 1 && store.multi_replace == 0) {
 594                                 fprintf(stderr,
 595                                         "Warning: %s has multiple values\n",
 596                                         key);
 597                         } else if (store.seen >= MAX_MATCHES) {
 598                                 fprintf(stderr, "Too many matches\n");
 599                                 return 1;
 600                         }
 601
 602                         store.offset[store.seen] = ftell(config_file);
 603                         store.seen++;
 604                 }
 605                 break;
 606         case SECTION_SEEN:
 607                 /*
 608                  * What we are looking for is in store.key (both
 609                  * section and var), and its section part is baselen
 610                  * long.  We found key (again, both section and var).
 611                  * We would want to know if this key is in the same
 612                  * section as what we are looking for.  We already
 613                  * know we are in the same section as what should
 614                  * hold store.key.
 615                  */
 616                 ep = strrchr(key, '.');
 617                 section_len = ep - key;
 618
 619                 if ((section_len != store.baselen) ||
 620                     memcmp(key, store.key, section_len+1)) {
 621                         store.state = SECTION_END_SEEN;
 622                         break;
 623                 }
 624
 625                 /*
 626                  * Do not increment matches: this is no match, but we
 627                  * just made sure we are in the desired section.
 628                  */
 629                 store.offset[store.seen] = ftell(config_file);
 630                 /* fallthru */
 631         case SECTION_END_SEEN:
 632         case START:
 633                 if (matches(key, value)) {
 634                         store.offset[store.seen] = ftell(config_file);
 635                         store.state = KEY_SEEN;
 636                         store.seen++;
 637                 } else {
 638                         if (strrchr(key, '.') - key == store.baselen &&
 639                               !strncmp(key, store.key, store.baselen)) {
 640                                         store.state = SECTION_SEEN;
 641                                         store.offset[store.seen] = ftell(config_file);
 642                         }
 643                 }
 644         }
 645         return 0;
 646 }
 647
 648 static int write_error(void)
 649 {
 650         fprintf(stderr, "Failed to write new configuration file\n");
 651
 652         /* Same error code as "failed to rename". */
 653         return 4;
 654 }
 655
 656 static int store_write_section(int fd, const char* key)
 657 {
 658         const char *dot;
 659         int i, success;
 660         struct strbuf sb;
 661
 662         strbuf_init(&sb, 0);
 663         dot = memchr(key, '.', store.baselen);
 664         if (dot) {
 665                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 666                 for (i = dot - key + 1; i < store.baselen; i++) {
 667                         if (key[i] == '"')
 668                                 strbuf_addch(&sb, '\\');
 669                         strbuf_addch(&sb, key[i]);
 670                 }
 671                 strbuf_addstr(&sb, "\"]\n");
 672         } else {
 673                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 674         }
 675
 676         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 677         strbuf_release(&sb);
 678
 679         return success;
 680 }
 681
 682 static int store_write_pair(int fd, const char* key, const char* value)
 683 {
 684         int i, success;
 685         int length = strlen(key + store.baselen + 1);
 686         const char *quote = "";
 687         struct strbuf sb;
 688
 689         /*
 690          * Check to see if the value needs to be surrounded with a dq pair.
 691          * Note that problematic characters are always backslash-quoted; this
 692          * check is about not losing leading or trailing SP and strings that
 693          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 694          * configuration parser.
 695          */
 696         if (value[0] == ' ')
 697                 quote = "\"";
 698         for (i = 0; value[i]; i++)
 699                 if (value[i] == ';' || value[i] == '#')
 700                         quote = "\"";
 701         if (i && value[i - 1] == ' ')
 702                 quote = "\"";
 703
 704         strbuf_init(&sb, 0);
 705         strbuf_addf(&sb, "\t%.*s = %s",
 706                     length, key + store.baselen + 1, quote);
 707
 708         for (i = 0; value[i]; i++)
 709                 switch (value[i]) {
 710                 case '\n':
 711                         strbuf_addstr(&sb, "\\n");
 712                         break;
 713                 case '\t':
 714                         strbuf_addstr(&sb, "\\t");
 715                         break;
 716                 case '"':
 717                 case '\\':
 718                         strbuf_addch(&sb, '\\');
 719                 default:
 720                         strbuf_addch(&sb, value[i]);
 721                         break;
 722                 }
 723         strbuf_addf(&sb, "%s\n", quote);
 724
 725         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 726         strbuf_release(&sb);
 727
 728         return success;
 729 }
 730
 731 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 732         size_t offset_, int* found_bracket)
 733 {
 734         size_t equal_offset = size, bracket_offset = size;
 735         ssize_t offset;
 736
 737 contline:
 738         for (offset = offset_-2; offset > 0
 739                         && contents[offset] != '\n'; offset--)
 740                 switch (contents[offset]) {
 741                         case '=': equal_offset = offset; break;
 742                         case ']': bracket_offset = offset; break;
 743                 }
 744         if (offset > 0 && contents[offset-1] == '\\') {
 745                 offset_ = offset;
 746                 goto contline;
 747         }
 748         if (bracket_offset < equal_offset) {
 749                 *found_bracket = 1;
 750                 offset = bracket_offset+1;
 751         } else
 752                 offset++;
 753
 754         return offset;
 755 }
 756
 757 int git_config_set(const char* key, const char* value)
 758 {
 759         return git_config_set_multivar(key, value, NULL, 0);
 760 }
 761
 762 /*
 763  * If value==NULL, unset in (remove from) config,
 764  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 765  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 766  *     else all matching key/values (regardless how many) are removed,
 767  *     before the new pair is written.
 768  *
 769  * Returns 0 on success.
 770  *
 771  * This function does this:
 772  *
 773  * - it locks the config file by creating ".git/config.lock"
 774  *
 775  * - it then parses the config using store_aux() as validator to find
 776  *   the position on the key/value pair to replace. If it is to be unset,
 777  *   it must be found exactly once.
 778  *
 779  * - the config file is mmap()ed and the part before the match (if any) is
 780  *   written to the lock file, then the changed part and the rest.
 781  *
 782  * - the config file is removed and the lock file rename()d to it.
 783  *
 784  */
 785 int git_config_set_multivar(const char* key, const char* value,
 786         const char* value_regex, int multi_replace)
 787 {
 788         int i, dot;
 789         int fd = -1, in_fd;
 790         int ret;
 791         char* config_filename;
 792         struct lock_file *lock = NULL;
 793         const char* last_dot = strrchr(key, '.');
 794
 795         config_filename = getenv(CONFIG_ENVIRONMENT);
 796         if (!config_filename) {
 797                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 798                 if (!config_filename)
 799                         config_filename  = git_path("config");
 800         }
 801         config_filename = xstrdup(config_filename);
 802
 803         /*
 804          * Since "key" actually contains the section name and the real
 805          * key name separated by a dot, we have to know where the dot is.
 806          */
 807
 808         if (last_dot == NULL) {
 809                 fprintf(stderr, "key does not contain a section: %s\n", key);
 810                 ret = 2;
 811                 goto out_free;
 812         }
 813         store.baselen = last_dot - key;
 814
 815         store.multi_replace = multi_replace;
 816
 817         /*
 818          * Validate the key and while at it, lower case it for matching.
 819          */
 820         store.key = xmalloc(strlen(key) + 1);
 821         dot = 0;
 822         for (i = 0; key[i]; i++) {
 823                 unsigned char c = key[i];
 824                 if (c == '.')
 825                         dot = 1;
 826                 /* Leave the extended basename untouched.. */
 827                 if (!dot || i > store.baselen) {
 828                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 829                                 fprintf(stderr, "invalid key: %s\n", key);
 830                                 free(store.key);
 831                                 ret = 1;
 832                                 goto out_free;
 833                         }
 834                         c = tolower(c);
 835                 } else if (c == '\n') {
 836                         fprintf(stderr, "invalid key (newline): %s\n", key);
 837                         free(store.key);
 838                         ret = 1;
 839                         goto out_free;
 840                 }
 841                 store.key[i] = c;
 842         }
 843         store.key[i] = 0;
 844
 845         /*
 846          * The lock serves a purpose in addition to locking: the new
 847          * contents of .git/config will be written into it.
 848          */
 849         lock = xcalloc(sizeof(struct lock_file), 1);
 850         fd = hold_lock_file_for_update(lock, config_filename, 0);
 851         if (fd < 0) {
 852                 fprintf(stderr, "could not lock config file\n");
 853                 free(store.key);
 854                 ret = -1;
 855                 goto out_free;
 856         }
 857
 858         /*
 859          * If .git/config does not exist yet, write a minimal version.
 860          */
 861         in_fd = open(config_filename, O_RDONLY);
 862         if ( in_fd < 0 ) {
 863                 free(store.key);
 864
 865                 if ( ENOENT != errno ) {
 866                         error("opening %s: %s", config_filename,
 867                               strerror(errno));
 868                         ret = 3; /* same as "invalid config file" */
 869                         goto out_free;
 870                 }
 871                 /* if nothing to unset, error out */
 872                 if (value == NULL) {
 873                         ret = 5;
 874                         goto out_free;
 875                 }
 876
 877                 store.key = (char*)key;
 878                 if (!store_write_section(fd, key) ||
 879                     !store_write_pair(fd, key, value))
 880                         goto write_err_out;
 881         } else {
 882                 struct stat st;
 883                 char* contents;
 884                 size_t contents_sz, copy_begin, copy_end;
 885                 int i, new_line = 0;
 886
 887                 if (value_regex == NULL)
 888                         store.value_regex = NULL;
 889                 else {
 890                         if (value_regex[0] == '!') {
 891                                 store.do_not_match = 1;
 892                                 value_regex++;
 893                         } else
 894                                 store.do_not_match = 0;
 895
 896                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 897                         if (regcomp(store.value_regex, value_regex,
 898                                         REG_EXTENDED)) {
 899                                 fprintf(stderr, "Invalid pattern: %s\n",
 900                                         value_regex);
 901                                 free(store.value_regex);
 902                                 ret = 6;
 903                                 goto out_free;
 904                         }
 905                 }
 906
 907                 store.offset[0] = 0;
 908                 store.state = START;
 909                 store.seen = 0;
 910
 911                 /*
 912                  * After this, store.offset will contain the *end* offset
 913                  * of the last match, or remain at 0 if no match was found.
 914                  * As a side effect, we make sure to transform only a valid
 915                  * existing config file.
 916                  */
 917                 if (git_config_from_file(store_aux, config_filename)) {
 918                         fprintf(stderr, "invalid config file\n");
 919                         free(store.key);
 920                         if (store.value_regex != NULL) {
 921                                 regfree(store.value_regex);
 922                                 free(store.value_regex);
 923                         }
 924                         ret = 3;
 925                         goto out_free;
 926                 }
 927
 928                 free(store.key);
 929                 if (store.value_regex != NULL) {
 930                         regfree(store.value_regex);
 931                         free(store.value_regex);
 932                 }
 933
 934                 /* if nothing to unset, or too many matches, error out */
 935                 if ((store.seen == 0 && value == NULL) ||
 936                                 (store.seen > 1 && multi_replace == 0)) {
 937                         ret = 5;
 938                         goto out_free;
 939                 }
 940
 941                 fstat(in_fd, &st);
 942                 contents_sz = xsize_t(st.st_size);
 943                 contents = xmmap(NULL, contents_sz, PROT_READ,
 944                         MAP_PRIVATE, in_fd, 0);
 945                 close(in_fd);
 946
 947                 if (store.seen == 0)
 948                         store.seen = 1;
 949
 950                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 951                         if (store.offset[i] == 0) {
 952                                 store.offset[i] = copy_end = contents_sz;
 953                         } else if (store.state != KEY_SEEN) {
 954                                 copy_end = store.offset[i];
 955                         } else
 956                                 copy_end = find_beginning_of_line(
 957                                         contents, contents_sz,
 958                                         store.offset[i]-2, &new_line);
 959
 960                         if (copy_end > 0 && contents[copy_end-1] != '\n')
 961                                 new_line = 1;
 962
 963                         /* write the first part of the config */
 964                         if (copy_end > copy_begin) {
 965                                 if (write_in_full(fd, contents + copy_begin,
 966                                                   copy_end - copy_begin) <
 967                                     copy_end - copy_begin)
 968                                         goto write_err_out;
 969                                 if (new_line &&
 970                                     write_in_full(fd, "\n", 1) != 1)
 971                                         goto write_err_out;
 972                         }
 973                         copy_begin = store.offset[i];
 974                 }
 975
 976                 /* write the pair (value == NULL means unset) */
 977                 if (value != NULL) {
 978                         if (store.state == START) {
 979                                 if (!store_write_section(fd, key))
 980                                         goto write_err_out;
 981                         }
 982                         if (!store_write_pair(fd, key, value))
 983                                 goto write_err_out;
 984                 }
 985
 986                 /* write the rest of the config */
 987                 if (copy_begin < contents_sz)
 988                         if (write_in_full(fd, contents + copy_begin,
 989                                           contents_sz - copy_begin) <
 990                             contents_sz - copy_begin)
 991                                 goto write_err_out;
 992
 993                 munmap(contents, contents_sz);
 994         }
 995
 996         if (commit_lock_file(lock) < 0) {
 997                 fprintf(stderr, "Cannot commit config file!\n");
 998                 ret = 4;
 999                 goto out_free;
1000         }
1001
1002         /*
1003          * lock is committed, so don't try to roll it back below.
1004          * NOTE: Since lockfile.c keeps a linked list of all created
1005          * lock_file structures, it isn't safe to free(lock).  It's
1006          * better to just leave it hanging around.
1007          */
1008         lock = NULL;
1009         ret = 0;
1010
1011 out_free:
1012         if (lock)
1013                 rollback_lock_file(lock);
1014         free(config_filename);
1015         return ret;
1016
1017 write_err_out:
1018         ret = write_error();
1019         goto out_free;
1020
1021 }
1022
1023 static int section_name_match (const char *buf, const char *name)
1024 {
1025         int i = 0, j = 0, dot = 0;
1026         for (; buf[i] && buf[i] != ']'; i++) {
1027                 if (!dot && isspace(buf[i])) {
1028                         dot = 1;
1029                         if (name[j++] != '.')
1030                                 break;
1031                         for (i++; isspace(buf[i]); i++)
1032                                 ; /* do nothing */
1033                         if (buf[i] != '"')
1034                                 break;
1035                         continue;
1036                 }
1037                 if (buf[i] == '\\' && dot)
1038                         i++;
1039                 else if (buf[i] == '"' && dot) {
1040                         for (i++; isspace(buf[i]); i++)
1041                                 ; /* do_nothing */
1042                         break;
1043                 }
1044                 if (buf[i] != name[j++])
1045                         break;
1046         }
1047         return (buf[i] == ']' && name[j] == 0);
1048 }
1049
1050 /* if new_name == NULL, the section is removed instead */
1051 int git_config_rename_section(const char *old_name, const char *new_name)
1052 {
1053         int ret = 0, remove = 0;
1054         char *config_filename;
1055         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1056         int out_fd;
1057         char buf[1024];
1058
1059         config_filename = getenv(CONFIG_ENVIRONMENT);
1060         if (!config_filename) {
1061                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1062                 if (!config_filename)
1063                         config_filename  = git_path("config");
1064         }
1065         config_filename = xstrdup(config_filename);
1066         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1067         if (out_fd < 0) {
1068                 ret = error("Could not lock config file!");
1069                 goto out;
1070         }
1071
1072         if (!(config_file = fopen(config_filename, "rb"))) {
1073                 /* no config file means nothing to rename, no error */
1074                 goto unlock_and_out;
1075         }
1076
1077         while (fgets(buf, sizeof(buf), config_file)) {
1078                 int i;
1079                 int length;
1080                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1081                         ; /* do nothing */
1082                 if (buf[i] == '[') {
1083                         /* it's a section */
1084                         if (section_name_match (&buf[i+1], old_name)) {
1085                                 ret++;
1086                                 if (new_name == NULL) {
1087                                         remove = 1;
1088                                         continue;
1089                                 }
1090                                 store.baselen = strlen(new_name);
1091                                 if (!store_write_section(out_fd, new_name)) {
1092                                         ret = write_error();
1093                                         goto out;
1094                                 }
1095                                 continue;
1096                         }
1097                         remove = 0;
1098                 }
1099                 if (remove)
1100                         continue;
1101                 length = strlen(buf);
1102                 if (write_in_full(out_fd, buf, length) != length) {
1103                         ret = write_error();
1104                         goto out;
1105                 }
1106         }
1107         fclose(config_file);
1108  unlock_and_out:
1109         if (commit_lock_file(lock) < 0)
1110                         ret = error("Cannot commit config file!");
1111  out:
1112         free(config_filename);
1113         return ret;
1114 }
1115
1116 /*
1117  * Call this to report error for your variable that should not
1118  * get a boolean value (i.e. "[my] var" means "true").
1119  */
1120 int config_error_nonbool(const char *var)
1121 {
1122         return error("Missing value for '%s'", var);
1123 }