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, void *data, 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, data);
 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, void *data)
 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, data, 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_or_int(const char *name, const char *value, int *is_bool)
 307 {
 308         *is_bool = 1;
 309         if (!value)
 310                 return 1;
 311         if (!*value)
 312                 return 0;
 313         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 314                 return 1;
 315         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 316                 return 0;
 317         *is_bool = 0;
 318         return git_config_int(name, value);
 319 }
 320
 321 int git_config_bool(const char *name, const char *value)
 322 {
 323         int discard;
 324         return !!git_config_bool_or_int(name, value, &discard);
 325 }
 326
 327 int git_config_string(const char **dest, const char *var, const char *value)
 328 {
 329         if (!value)
 330                 return config_error_nonbool(var);
 331         *dest = xstrdup(value);
 332         return 0;
 333 }
 334
 335 static int git_default_core_config(const char *var, const char *value)
 336 {
 337         /* This needs a better name */
 338         if (!strcmp(var, "core.filemode")) {
 339                 trust_executable_bit = git_config_bool(var, value);
 340                 return 0;
 341         }
 342
 343         if (!strcmp(var, "core.quotepath")) {
 344                 quote_path_fully = git_config_bool(var, value);
 345                 return 0;
 346         }
 347
 348         if (!strcmp(var, "core.symlinks")) {
 349                 has_symlinks = git_config_bool(var, value);
 350                 return 0;
 351         }
 352
 353         if (!strcmp(var, "core.ignorecase")) {
 354                 ignore_case = git_config_bool(var, value);
 355                 return 0;
 356         }
 357
 358         if (!strcmp(var, "core.bare")) {
 359                 is_bare_repository_cfg = git_config_bool(var, value);
 360                 return 0;
 361         }
 362
 363         if (!strcmp(var, "core.ignorestat")) {
 364                 assume_unchanged = git_config_bool(var, value);
 365                 return 0;
 366         }
 367
 368         if (!strcmp(var, "core.prefersymlinkrefs")) {
 369                 prefer_symlink_refs = git_config_bool(var, value);
 370                 return 0;
 371         }
 372
 373         if (!strcmp(var, "core.logallrefupdates")) {
 374                 log_all_ref_updates = git_config_bool(var, value);
 375                 return 0;
 376         }
 377
 378         if (!strcmp(var, "core.warnambiguousrefs")) {
 379                 warn_ambiguous_refs = git_config_bool(var, value);
 380                 return 0;
 381         }
 382
 383         if (!strcmp(var, "core.loosecompression")) {
 384                 int level = git_config_int(var, value);
 385                 if (level == -1)
 386                         level = Z_DEFAULT_COMPRESSION;
 387                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 388                         die("bad zlib compression level %d", level);
 389                 zlib_compression_level = level;
 390                 zlib_compression_seen = 1;
 391                 return 0;
 392         }
 393
 394         if (!strcmp(var, "core.compression")) {
 395                 int level = git_config_int(var, value);
 396                 if (level == -1)
 397                         level = Z_DEFAULT_COMPRESSION;
 398                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 399                         die("bad zlib compression level %d", level);
 400                 core_compression_level = level;
 401                 core_compression_seen = 1;
 402                 if (!zlib_compression_seen)
 403                         zlib_compression_level = level;
 404                 return 0;
 405         }
 406
 407         if (!strcmp(var, "core.packedgitwindowsize")) {
 408                 int pgsz_x2 = getpagesize() * 2;
 409                 packed_git_window_size = git_config_int(var, value);
 410
 411                 /* This value must be multiple of (pagesize * 2) */
 412                 packed_git_window_size /= pgsz_x2;
 413                 if (packed_git_window_size < 1)
 414                         packed_git_window_size = 1;
 415                 packed_git_window_size *= pgsz_x2;
 416                 return 0;
 417         }
 418
 419         if (!strcmp(var, "core.packedgitlimit")) {
 420                 packed_git_limit = git_config_int(var, value);
 421                 return 0;
 422         }
 423
 424         if (!strcmp(var, "core.deltabasecachelimit")) {
 425                 delta_base_cache_limit = git_config_int(var, value);
 426                 return 0;
 427         }
 428
 429         if (!strcmp(var, "core.autocrlf")) {
 430                 if (value && !strcasecmp(value, "input")) {
 431                         auto_crlf = -1;
 432                         return 0;
 433                 }
 434                 auto_crlf = git_config_bool(var, value);
 435                 return 0;
 436         }
 437
 438         if (!strcmp(var, "core.safecrlf")) {
 439                 if (value && !strcasecmp(value, "warn")) {
 440                         safe_crlf = SAFE_CRLF_WARN;
 441                         return 0;
 442                 }
 443                 safe_crlf = git_config_bool(var, value);
 444                 return 0;
 445         }
 446
 447         if (!strcmp(var, "core.pager"))
 448                 return git_config_string(&pager_program, var, value);
 449
 450         if (!strcmp(var, "core.editor"))
 451                 return git_config_string(&editor_program, var, value);
 452
 453         if (!strcmp(var, "core.excludesfile"))
 454                 return git_config_string(&excludes_file, var, value);
 455
 456         if (!strcmp(var, "core.whitespace")) {
 457                 if (!value)
 458                         return config_error_nonbool(var);
 459                 whitespace_rule_cfg = parse_whitespace_rule(value);
 460                 return 0;
 461         }
 462
 463         /* Add other config variables here and to Documentation/config.txt. */
 464         return 0;
 465 }
 466
 467 int git_default_config(const char *var, const char *value, void *dummy)
 468 {
 469         if (!prefixcmp(var, "core."))
 470                 return git_default_core_config(var, value);
 471
 472         if (!strcmp(var, "user.name")) {
 473                 if (!value)
 474                         return config_error_nonbool(var);
 475                 strlcpy(git_default_name, value, sizeof(git_default_name));
 476                 if (git_default_email[0])
 477                         user_ident_explicitly_given = 1;
 478                 return 0;
 479         }
 480
 481         if (!strcmp(var, "user.email")) {
 482                 if (!value)
 483                         return config_error_nonbool(var);
 484                 strlcpy(git_default_email, value, sizeof(git_default_email));
 485                 if (git_default_name[0])
 486                         user_ident_explicitly_given = 1;
 487                 return 0;
 488         }
 489
 490         if (!strcmp(var, "i18n.commitencoding"))
 491                 return git_config_string(&git_commit_encoding, var, value);
 492
 493         if (!strcmp(var, "i18n.logoutputencoding"))
 494                 return git_config_string(&git_log_output_encoding, var, value);
 495
 496         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 497                 pager_use_color = git_config_bool(var,value);
 498                 return 0;
 499         }
 500
 501         if (!strcmp(var, "branch.autosetupmerge")) {
 502                 if (value && !strcasecmp(value, "always")) {
 503                         git_branch_track = BRANCH_TRACK_ALWAYS;
 504                         return 0;
 505                 }
 506                 git_branch_track = git_config_bool(var, value);
 507                 return 0;
 508         }
 509         if (!strcmp(var, "branch.autosetuprebase")) {
 510                 if (!value)
 511                         return config_error_nonbool(var);
 512                 else if (!strcmp(value, "never"))
 513                         autorebase = AUTOREBASE_NEVER;
 514                 else if (!strcmp(value, "local"))
 515                         autorebase = AUTOREBASE_LOCAL;
 516                 else if (!strcmp(value, "remote"))
 517                         autorebase = AUTOREBASE_REMOTE;
 518                 else if (!strcmp(value, "always"))
 519                         autorebase = AUTOREBASE_ALWAYS;
 520                 else
 521                         return error("Malformed value for %s", var);
 522                 return 0;
 523         }
 524
 525         /* Add other config variables here and to Documentation/config.txt. */
 526         return 0;
 527 }
 528
 529 int git_config_from_file(config_fn_t fn, const char *filename, void *data)
 530 {
 531         int ret;
 532         FILE *f = fopen(filename, "r");
 533
 534         ret = -1;
 535         if (f) {
 536                 config_file = f;
 537                 config_file_name = filename;
 538                 config_linenr = 1;
 539                 config_file_eof = 0;
 540                 ret = git_parse_file(fn, data);
 541                 fclose(f);
 542                 config_file_name = NULL;
 543         }
 544         return ret;
 545 }
 546
 547 const char *git_etc_gitconfig(void)
 548 {
 549         static const char *system_wide;
 550         if (!system_wide) {
 551                 system_wide = ETC_GITCONFIG;
 552                 if (!is_absolute_path(system_wide)) {
 553                         /* interpret path relative to exec-dir */
 554                         struct strbuf d = STRBUF_INIT;
 555                         strbuf_addf(&d, "%s/%s", git_exec_path(), system_wide);
 556                         system_wide = strbuf_detach(&d, NULL);
 557                 }
 558         }
 559         return system_wide;
 560 }
 561
 562 int git_env_bool(const char *k, int def)
 563 {
 564         const char *v = getenv(k);
 565         return v ? git_config_bool(k, v) : def;
 566 }
 567
 568 int git_config_system(void)
 569 {
 570         return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
 571 }
 572
 573 int git_config_global(void)
 574 {
 575         return !git_env_bool("GIT_CONFIG_NOGLOBAL", 0);
 576 }
 577
 578 int git_config(config_fn_t fn, void *data)
 579 {
 580         int ret = 0;
 581         char *repo_config = NULL;
 582         const char *home = NULL, *filename;
 583
 584         /* $GIT_CONFIG makes git read _only_ the given config file,
 585          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 586          * global config file, the same way it would the per-repository
 587          * config file otherwise. */
 588         filename = getenv(CONFIG_ENVIRONMENT);
 589         if (!filename) {
 590                 if (git_config_system() && !access(git_etc_gitconfig(), R_OK))
 591                         ret += git_config_from_file(fn, git_etc_gitconfig(),
 592                                 data);
 593                 home = getenv("HOME");
 594                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 595                 if (!filename)
 596                         filename = repo_config = xstrdup(git_path("config"));
 597         }
 598
 599         if (git_config_global() && home) {
 600                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 601                 if (!access(user_config, R_OK))
 602                         ret = git_config_from_file(fn, user_config, data);
 603                 free(user_config);
 604         }
 605
 606         ret += git_config_from_file(fn, filename, data);
 607         free(repo_config);
 608         return ret;
 609 }
 610
 611 /*
 612  * Find all the stuff for git_config_set() below.
 613  */
 614
 615 #define MAX_MATCHES 512
 616
 617 static struct {
 618         int baselen;
 619         char* key;
 620         int do_not_match;
 621         regex_t* value_regex;
 622         int multi_replace;
 623         size_t offset[MAX_MATCHES];
 624         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 625         int seen;
 626 } store;
 627
 628 static int matches(const char* key, const char* value)
 629 {
 630         return !strcmp(key, store.key) &&
 631                 (store.value_regex == NULL ||
 632                  (store.do_not_match ^
 633                   !regexec(store.value_regex, value, 0, NULL, 0)));
 634 }
 635
 636 static int store_aux(const char* key, const char* value, void *cb)
 637 {
 638         const char *ep;
 639         size_t section_len;
 640
 641         switch (store.state) {
 642         case KEY_SEEN:
 643                 if (matches(key, value)) {
 644                         if (store.seen == 1 && store.multi_replace == 0) {
 645                                 warning("%s has multiple values", key);
 646                         } else if (store.seen >= MAX_MATCHES) {
 647                                 error("too many matches for %s", key);
 648                                 return 1;
 649                         }
 650
 651                         store.offset[store.seen] = ftell(config_file);
 652                         store.seen++;
 653                 }
 654                 break;
 655         case SECTION_SEEN:
 656                 /*
 657                  * What we are looking for is in store.key (both
 658                  * section and var), and its section part is baselen
 659                  * long.  We found key (again, both section and var).
 660                  * We would want to know if this key is in the same
 661                  * section as what we are looking for.  We already
 662                  * know we are in the same section as what should
 663                  * hold store.key.
 664                  */
 665                 ep = strrchr(key, '.');
 666                 section_len = ep - key;
 667
 668                 if ((section_len != store.baselen) ||
 669                     memcmp(key, store.key, section_len+1)) {
 670                         store.state = SECTION_END_SEEN;
 671                         break;
 672                 }
 673
 674                 /*
 675                  * Do not increment matches: this is no match, but we
 676                  * just made sure we are in the desired section.
 677                  */
 678                 store.offset[store.seen] = ftell(config_file);
 679                 /* fallthru */
 680         case SECTION_END_SEEN:
 681         case START:
 682                 if (matches(key, value)) {
 683                         store.offset[store.seen] = ftell(config_file);
 684                         store.state = KEY_SEEN;
 685                         store.seen++;
 686                 } else {
 687                         if (strrchr(key, '.') - key == store.baselen &&
 688                               !strncmp(key, store.key, store.baselen)) {
 689                                         store.state = SECTION_SEEN;
 690                                         store.offset[store.seen] = ftell(config_file);
 691                         }
 692                 }
 693         }
 694         return 0;
 695 }
 696
 697 static int write_error(const char *filename)
 698 {
 699         error("failed to write new configuration file %s", filename);
 700
 701         /* Same error code as "failed to rename". */
 702         return 4;
 703 }
 704
 705 static int store_write_section(int fd, const char* key)
 706 {
 707         const char *dot;
 708         int i, success;
 709         struct strbuf sb;
 710
 711         strbuf_init(&sb, 0);
 712         dot = memchr(key, '.', store.baselen);
 713         if (dot) {
 714                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 715                 for (i = dot - key + 1; i < store.baselen; i++) {
 716                         if (key[i] == '"' || key[i] == '\\')
 717                                 strbuf_addch(&sb, '\\');
 718                         strbuf_addch(&sb, key[i]);
 719                 }
 720                 strbuf_addstr(&sb, "\"]\n");
 721         } else {
 722                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 723         }
 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 int store_write_pair(int fd, const char* key, const char* value)
 732 {
 733         int i, success;
 734         int length = strlen(key + store.baselen + 1);
 735         const char *quote = "";
 736         struct strbuf sb;
 737
 738         /*
 739          * Check to see if the value needs to be surrounded with a dq pair.
 740          * Note that problematic characters are always backslash-quoted; this
 741          * check is about not losing leading or trailing SP and strings that
 742          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 743          * configuration parser.
 744          */
 745         if (value[0] == ' ')
 746                 quote = "\"";
 747         for (i = 0; value[i]; i++)
 748                 if (value[i] == ';' || value[i] == '#')
 749                         quote = "\"";
 750         if (i && value[i - 1] == ' ')
 751                 quote = "\"";
 752
 753         strbuf_init(&sb, 0);
 754         strbuf_addf(&sb, "\t%.*s = %s",
 755                     length, key + store.baselen + 1, quote);
 756
 757         for (i = 0; value[i]; i++)
 758                 switch (value[i]) {
 759                 case '\n':
 760                         strbuf_addstr(&sb, "\\n");
 761                         break;
 762                 case '\t':
 763                         strbuf_addstr(&sb, "\\t");
 764                         break;
 765                 case '"':
 766                 case '\\':
 767                         strbuf_addch(&sb, '\\');
 768                 default:
 769                         strbuf_addch(&sb, value[i]);
 770                         break;
 771                 }
 772         strbuf_addf(&sb, "%s\n", quote);
 773
 774         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 775         strbuf_release(&sb);
 776
 777         return success;
 778 }
 779
 780 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 781         size_t offset_, int* found_bracket)
 782 {
 783         size_t equal_offset = size, bracket_offset = size;
 784         ssize_t offset;
 785
 786 contline:
 787         for (offset = offset_-2; offset > 0
 788                         && contents[offset] != '\n'; offset--)
 789                 switch (contents[offset]) {
 790                         case '=': equal_offset = offset; break;
 791                         case ']': bracket_offset = offset; break;
 792                 }
 793         if (offset > 0 && contents[offset-1] == '\\') {
 794                 offset_ = offset;
 795                 goto contline;
 796         }
 797         if (bracket_offset < equal_offset) {
 798                 *found_bracket = 1;
 799                 offset = bracket_offset+1;
 800         } else
 801                 offset++;
 802
 803         return offset;
 804 }
 805
 806 int git_config_set(const char* key, const char* value)
 807 {
 808         return git_config_set_multivar(key, value, NULL, 0);
 809 }
 810
 811 /*
 812  * If value==NULL, unset in (remove from) config,
 813  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 814  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 815  *     else all matching key/values (regardless how many) are removed,
 816  *     before the new pair is written.
 817  *
 818  * Returns 0 on success.
 819  *
 820  * This function does this:
 821  *
 822  * - it locks the config file by creating ".git/config.lock"
 823  *
 824  * - it then parses the config using store_aux() as validator to find
 825  *   the position on the key/value pair to replace. If it is to be unset,
 826  *   it must be found exactly once.
 827  *
 828  * - the config file is mmap()ed and the part before the match (if any) is
 829  *   written to the lock file, then the changed part and the rest.
 830  *
 831  * - the config file is removed and the lock file rename()d to it.
 832  *
 833  */
 834 int git_config_set_multivar(const char* key, const char* value,
 835         const char* value_regex, int multi_replace)
 836 {
 837         int i, dot;
 838         int fd = -1, in_fd;
 839         int ret;
 840         char* config_filename;
 841         struct lock_file *lock = NULL;
 842         const char* last_dot = strrchr(key, '.');
 843
 844         config_filename = getenv(CONFIG_ENVIRONMENT);
 845         if (!config_filename) {
 846                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 847                 if (!config_filename)
 848                         config_filename  = git_path("config");
 849         }
 850         config_filename = xstrdup(config_filename);
 851
 852         /*
 853          * Since "key" actually contains the section name and the real
 854          * key name separated by a dot, we have to know where the dot is.
 855          */
 856
 857         if (last_dot == NULL) {
 858                 error("key does not contain a section: %s", key);
 859                 ret = 2;
 860                 goto out_free;
 861         }
 862         store.baselen = last_dot - key;
 863
 864         store.multi_replace = multi_replace;
 865
 866         /*
 867          * Validate the key and while at it, lower case it for matching.
 868          */
 869         store.key = xmalloc(strlen(key) + 1);
 870         dot = 0;
 871         for (i = 0; key[i]; i++) {
 872                 unsigned char c = key[i];
 873                 if (c == '.')
 874                         dot = 1;
 875                 /* Leave the extended basename untouched.. */
 876                 if (!dot || i > store.baselen) {
 877                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 878                                 error("invalid key: %s", key);
 879                                 free(store.key);
 880                                 ret = 1;
 881                                 goto out_free;
 882                         }
 883                         c = tolower(c);
 884                 } else if (c == '\n') {
 885                         error("invalid key (newline): %s", key);
 886                         free(store.key);
 887                         ret = 1;
 888                         goto out_free;
 889                 }
 890                 store.key[i] = c;
 891         }
 892         store.key[i] = 0;
 893
 894         /*
 895          * The lock serves a purpose in addition to locking: the new
 896          * contents of .git/config will be written into it.
 897          */
 898         lock = xcalloc(sizeof(struct lock_file), 1);
 899         fd = hold_lock_file_for_update(lock, config_filename, 0);
 900         if (fd < 0) {
 901                 error("could not lock config file %s", config_filename);
 902                 free(store.key);
 903                 ret = -1;
 904                 goto out_free;
 905         }
 906
 907         /*
 908          * If .git/config does not exist yet, write a minimal version.
 909          */
 910         in_fd = open(config_filename, O_RDONLY);
 911         if ( in_fd < 0 ) {
 912                 free(store.key);
 913
 914                 if ( ENOENT != errno ) {
 915                         error("opening %s: %s", config_filename,
 916                               strerror(errno));
 917                         ret = 3; /* same as "invalid config file" */
 918                         goto out_free;
 919                 }
 920                 /* if nothing to unset, error out */
 921                 if (value == NULL) {
 922                         ret = 5;
 923                         goto out_free;
 924                 }
 925
 926                 store.key = (char*)key;
 927                 if (!store_write_section(fd, key) ||
 928                     !store_write_pair(fd, key, value))
 929                         goto write_err_out;
 930         } else {
 931                 struct stat st;
 932                 char* contents;
 933                 size_t contents_sz, copy_begin, copy_end;
 934                 int i, new_line = 0;
 935
 936                 if (value_regex == NULL)
 937                         store.value_regex = NULL;
 938                 else {
 939                         if (value_regex[0] == '!') {
 940                                 store.do_not_match = 1;
 941                                 value_regex++;
 942                         } else
 943                                 store.do_not_match = 0;
 944
 945                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 946                         if (regcomp(store.value_regex, value_regex,
 947                                         REG_EXTENDED)) {
 948                                 error("invalid pattern: %s", value_regex);
 949                                 free(store.value_regex);
 950                                 ret = 6;
 951                                 goto out_free;
 952                         }
 953                 }
 954
 955                 store.offset[0] = 0;
 956                 store.state = START;
 957                 store.seen = 0;
 958
 959                 /*
 960                  * After this, store.offset will contain the *end* offset
 961                  * of the last match, or remain at 0 if no match was found.
 962                  * As a side effect, we make sure to transform only a valid
 963                  * existing config file.
 964                  */
 965                 if (git_config_from_file(store_aux, config_filename, NULL)) {
 966                         error("invalid config file %s", config_filename);
 967                         free(store.key);
 968                         if (store.value_regex != NULL) {
 969                                 regfree(store.value_regex);
 970                                 free(store.value_regex);
 971                         }
 972                         ret = 3;
 973                         goto out_free;
 974                 }
 975
 976                 free(store.key);
 977                 if (store.value_regex != NULL) {
 978                         regfree(store.value_regex);
 979                         free(store.value_regex);
 980                 }
 981
 982                 /* if nothing to unset, or too many matches, error out */
 983                 if ((store.seen == 0 && value == NULL) ||
 984                                 (store.seen > 1 && multi_replace == 0)) {
 985                         ret = 5;
 986                         goto out_free;
 987                 }
 988
 989                 fstat(in_fd, &st);
 990                 contents_sz = xsize_t(st.st_size);
 991                 contents = xmmap(NULL, contents_sz, PROT_READ,
 992                         MAP_PRIVATE, in_fd, 0);
 993                 close(in_fd);
 994
 995                 if (store.seen == 0)
 996                         store.seen = 1;
 997
 998                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 999                         if (store.offset[i] == 0) {
1000                                 store.offset[i] = copy_end = contents_sz;
1001                         } else if (store.state != KEY_SEEN) {
1002                                 copy_end = store.offset[i];
1003                         } else
1004                                 copy_end = find_beginning_of_line(
1005                                         contents, contents_sz,
1006                                         store.offset[i]-2, &new_line);
1007
1008                         if (copy_end > 0 && contents[copy_end-1] != '\n')
1009                                 new_line = 1;
1010
1011                         /* write the first part of the config */
1012                         if (copy_end > copy_begin) {
1013                                 if (write_in_full(fd, contents + copy_begin,
1014                                                   copy_end - copy_begin) <
1015                                     copy_end - copy_begin)
1016                                         goto write_err_out;
1017                                 if (new_line &&
1018                                     write_in_full(fd, "\n", 1) != 1)
1019                                         goto write_err_out;
1020                         }
1021                         copy_begin = store.offset[i];
1022                 }
1023
1024                 /* write the pair (value == NULL means unset) */
1025                 if (value != NULL) {
1026                         if (store.state == START) {
1027                                 if (!store_write_section(fd, key))
1028                                         goto write_err_out;
1029                         }
1030                         if (!store_write_pair(fd, key, value))
1031                                 goto write_err_out;
1032                 }
1033
1034                 /* write the rest of the config */
1035                 if (copy_begin < contents_sz)
1036                         if (write_in_full(fd, contents + copy_begin,
1037                                           contents_sz - copy_begin) <
1038                             contents_sz - copy_begin)
1039                                 goto write_err_out;
1040
1041                 munmap(contents, contents_sz);
1042         }
1043
1044         if (commit_lock_file(lock) < 0) {
1045                 error("could not commit config file %s", config_filename);
1046                 ret = 4;
1047                 goto out_free;
1048         }
1049
1050         /*
1051          * lock is committed, so don't try to roll it back below.
1052          * NOTE: Since lockfile.c keeps a linked list of all created
1053          * lock_file structures, it isn't safe to free(lock).  It's
1054          * better to just leave it hanging around.
1055          */
1056         lock = NULL;
1057         ret = 0;
1058
1059 out_free:
1060         if (lock)
1061                 rollback_lock_file(lock);
1062         free(config_filename);
1063         return ret;
1064
1065 write_err_out:
1066         ret = write_error(lock->filename);
1067         goto out_free;
1068
1069 }
1070
1071 static int section_name_match (const char *buf, const char *name)
1072 {
1073         int i = 0, j = 0, dot = 0;
1074         for (; buf[i] && buf[i] != ']'; i++) {
1075                 if (!dot && isspace(buf[i])) {
1076                         dot = 1;
1077                         if (name[j++] != '.')
1078                                 break;
1079                         for (i++; isspace(buf[i]); i++)
1080                                 ; /* do nothing */
1081                         if (buf[i] != '"')
1082                                 break;
1083                         continue;
1084                 }
1085                 if (buf[i] == '\\' && dot)
1086                         i++;
1087                 else if (buf[i] == '"' && dot) {
1088                         for (i++; isspace(buf[i]); i++)
1089                                 ; /* do_nothing */
1090                         break;
1091                 }
1092                 if (buf[i] != name[j++])
1093                         break;
1094         }
1095         return (buf[i] == ']' && name[j] == 0);
1096 }
1097
1098 /* if new_name == NULL, the section is removed instead */
1099 int git_config_rename_section(const char *old_name, const char *new_name)
1100 {
1101         int ret = 0, remove = 0;
1102         char *config_filename;
1103         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1104         int out_fd;
1105         char buf[1024];
1106
1107         config_filename = getenv(CONFIG_ENVIRONMENT);
1108         if (!config_filename) {
1109                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1110                 if (!config_filename)
1111                         config_filename  = git_path("config");
1112         }
1113         config_filename = xstrdup(config_filename);
1114         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1115         if (out_fd < 0) {
1116                 ret = error("could not lock config file %s", config_filename);
1117                 goto out;
1118         }
1119
1120         if (!(config_file = fopen(config_filename, "rb"))) {
1121                 /* no config file means nothing to rename, no error */
1122                 goto unlock_and_out;
1123         }
1124
1125         while (fgets(buf, sizeof(buf), config_file)) {
1126                 int i;
1127                 int length;
1128                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1129                         ; /* do nothing */
1130                 if (buf[i] == '[') {
1131                         /* it's a section */
1132                         if (section_name_match (&buf[i+1], old_name)) {
1133                                 ret++;
1134                                 if (new_name == NULL) {
1135                                         remove = 1;
1136                                         continue;
1137                                 }
1138                                 store.baselen = strlen(new_name);
1139                                 if (!store_write_section(out_fd, new_name)) {
1140                                         ret = write_error(lock->filename);
1141                                         goto out;
1142                                 }
1143                                 continue;
1144                         }
1145                         remove = 0;
1146                 }
1147                 if (remove)
1148                         continue;
1149                 length = strlen(buf);
1150                 if (write_in_full(out_fd, buf, length) != length) {
1151                         ret = write_error(lock->filename);
1152                         goto out;
1153                 }
1154         }
1155         fclose(config_file);
1156  unlock_and_out:
1157         if (commit_lock_file(lock) < 0)
1158                 ret = error("could not commit config file %s", config_filename);
1159  out:
1160         free(config_filename);
1161         return ret;
1162 }
1163
1164 /*
1165  * Call this to report error for your variable that should not
1166  * get a boolean value (i.e. "[my] var" means "true").
1167  */
1168 int config_error_nonbool(const char *var)
1169 {
1170         return error("Missing value for '%s'", var);
1171 }