Andrew's git / gitweb.git / config.c
?
config.con commit remote.c: "git-push frotz" should update what matches at the source. (1ed10b8)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 * Copyright (C) Johannes Schindelin, 2005
   6 *
   7 */
   8#include "cache.h"
   9
  10#define MAXNAME (256)
  11
  12static FILE *config_file;
  13static const char *config_file_name;
  14static int config_linenr;
  15static int zlib_compression_seen;
  16
  17static int get_next_char(void)
  18{
  19        int c;
  20        FILE *f;
  21
  22        c = '\n';
  23        if ((f = config_file) != NULL) {
  24                c = fgetc(f);
  25                if (c == '\r') {
  26                        /* DOS like systems */
  27                        c = fgetc(f);
  28                        if (c != '\n') {
  29                                ungetc(c, f);
  30                                c = '\r';
  31                        }
  32                }
  33                if (c == '\n')
  34                        config_linenr++;
  35                if (c == EOF) {
  36                        config_file = NULL;
  37                        c = '\n';
  38                }
  39        }
  40        return c;
  41}
  42
  43static char *parse_value(void)
  44{
  45        static char value[1024];
  46        int quote = 0, comment = 0, len = 0, space = 0;
  47
  48        for (;;) {
  49                int c = get_next_char();
  50                if (len >= sizeof(value))
  51                        return NULL;
  52                if (c == '\n') {
  53                        if (quote)
  54                                return NULL;
  55                        value[len] = 0;
  56                        return value;
  57                }
  58                if (comment)
  59                        continue;
  60                if (isspace(c) && !quote) {
  61                        space = 1;
  62                        continue;
  63                }
  64                if (!quote) {
  65                        if (c == ';' || c == '#') {
  66                                comment = 1;
  67                                continue;
  68                        }
  69                }
  70                if (space) {
  71                        if (len)
  72                                value[len++] = ' ';
  73                        space = 0;
  74                }
  75                if (c == '\\') {
  76                        c = get_next_char();
  77                        switch (c) {
  78                        case '\n':
  79                                continue;
  80                        case 't':
  81                                c = '\t';
  82                                break;
  83                        case 'b':
  84                                c = '\b';
  85                                break;
  86                        case 'n':
  87                                c = '\n';
  88                                break;
  89                        /* Some characters escape as themselves */
  90                        case '\\': case '"':
  91                                break;
  92                        /* Reject unknown escape sequences */
  93                        default:
  94                                return NULL;
  95                        }
  96                        value[len++] = c;
  97                        continue;
  98                }
  99                if (c == '"') {
 100                        quote = 1-quote;
 101                        continue;
 102                }
 103                value[len++] = c;
 104        }
 105}
 106
 107static inline int iskeychar(int c)
 108{
 109        return isalnum(c) || c == '-';
 110}
 111
 112static int get_value(config_fn_t fn, char *name, unsigned int len)
 113{
 114        int c;
 115        char *value;
 116
 117        /* Get the full name */
 118        for (;;) {
 119                c = get_next_char();
 120                if (c == EOF)
 121                        break;
 122                if (!iskeychar(c))
 123                        break;
 124                name[len++] = tolower(c);
 125                if (len >= MAXNAME)
 126                        return -1;
 127        }
 128        name[len] = 0;
 129        while (c == ' ' || c == '\t')
 130                c = get_next_char();
 131
 132        value = NULL;
 133        if (c != '\n') {
 134                if (c != '=')
 135                        return -1;
 136                value = parse_value();
 137                if (!value)
 138                        return -1;
 139        }
 140        return fn(name, value);
 141}
 142
 143static int get_extended_base_var(char *name, int baselen, int c)
 144{
 145        do {
 146                if (c == '\n')
 147                        return -1;
 148                c = get_next_char();
 149        } while (isspace(c));
 150
 151        /* We require the format to be '[base "extension"]' */
 152        if (c != '"')
 153                return -1;
 154        name[baselen++] = '.';
 155
 156        for (;;) {
 157                int c = get_next_char();
 158                if (c == '\n')
 159                        return -1;
 160                if (c == '"')
 161                        break;
 162                if (c == '\\') {
 163                        c = get_next_char();
 164                        if (c == '\n')
 165                                return -1;
 166                }
 167                name[baselen++] = c;
 168                if (baselen > MAXNAME / 2)
 169                        return -1;
 170        }
 171
 172        /* Final ']' */
 173        if (get_next_char() != ']')
 174                return -1;
 175        return baselen;
 176}
 177
 178static int get_base_var(char *name)
 179{
 180        int baselen = 0;
 181
 182        for (;;) {
 183                int c = get_next_char();
 184                if (c == EOF)
 185                        return -1;
 186                if (c == ']')
 187                        return baselen;
 188                if (isspace(c))
 189                        return get_extended_base_var(name, baselen, c);
 190                if (!iskeychar(c) && c != '.')
 191                        return -1;
 192                if (baselen > MAXNAME / 2)
 193                        return -1;
 194                name[baselen++] = tolower(c);
 195        }
 196}
 197
 198static int git_parse_file(config_fn_t fn)
 199{
 200        int comment = 0;
 201        int baselen = 0;
 202        static char var[MAXNAME];
 203
 204        for (;;) {
 205                int c = get_next_char();
 206                if (c == '\n') {
 207                        /* EOF? */
 208                        if (!config_file)
 209                                return 0;
 210                        comment = 0;
 211                        continue;
 212                }
 213                if (comment || isspace(c))
 214                        continue;
 215                if (c == '#' || c == ';') {
 216                        comment = 1;
 217                        continue;
 218                }
 219                if (c == '[') {
 220                        baselen = get_base_var(var);
 221                        if (baselen <= 0)
 222                                break;
 223                        var[baselen++] = '.';
 224                        var[baselen] = 0;
 225                        continue;
 226                }
 227                if (!isalpha(c))
 228                        break;
 229                var[baselen] = tolower(c);
 230                if (get_value(fn, var, baselen+1) < 0)
 231                        break;
 232        }
 233        die("bad config file line %d in %s", config_linenr, config_file_name);
 234}
 235
 236int git_config_int(const char *name, const char *value)
 237{
 238        if (value && *value) {
 239                char *end;
 240                int val = strtol(value, &end, 0);
 241                if (!*end)
 242                        return val;
 243                if (!strcasecmp(end, "k"))
 244                        return val * 1024;
 245                if (!strcasecmp(end, "m"))
 246                        return val * 1024 * 1024;
 247                if (!strcasecmp(end, "g"))
 248                        return val * 1024 * 1024 * 1024;
 249        }
 250        die("bad config value for '%s' in %s", name, config_file_name);
 251}
 252
 253int git_config_bool(const char *name, const char *value)
 254{
 255        if (!value)
 256                return 1;
 257        if (!*value)
 258                return 0;
 259        if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 260                return 1;
 261        if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 262                return 0;
 263        return git_config_int(name, value) != 0;
 264}
 265
 266int git_default_config(const char *var, const char *value)
 267{
 268        /* This needs a better name */
 269        if (!strcmp(var, "core.filemode")) {
 270                trust_executable_bit = git_config_bool(var, value);
 271                return 0;
 272        }
 273
 274        if (!strcmp(var, "core.symlinks")) {
 275                has_symlinks = git_config_bool(var, value);
 276                return 0;
 277        }
 278
 279        if (!strcmp(var, "core.bare")) {
 280                is_bare_repository_cfg = git_config_bool(var, value);
 281                return 0;
 282        }
 283
 284        if (!strcmp(var, "core.ignorestat")) {
 285                assume_unchanged = git_config_bool(var, value);
 286                return 0;
 287        }
 288
 289        if (!strcmp(var, "core.prefersymlinkrefs")) {
 290                prefer_symlink_refs = git_config_bool(var, value);
 291                return 0;
 292        }
 293
 294        if (!strcmp(var, "core.logallrefupdates")) {
 295                log_all_ref_updates = git_config_bool(var, value);
 296                return 0;
 297        }
 298
 299        if (!strcmp(var, "core.warnambiguousrefs")) {
 300                warn_ambiguous_refs = git_config_bool(var, value);
 301                return 0;
 302        }
 303
 304        if (!strcmp(var, "core.loosecompression")) {
 305                int level = git_config_int(var, value);
 306                if (level == -1)
 307                        level = Z_DEFAULT_COMPRESSION;
 308                else if (level < 0 || level > Z_BEST_COMPRESSION)
 309                        die("bad zlib compression level %d", level);
 310                zlib_compression_level = level;
 311                zlib_compression_seen = 1;
 312                return 0;
 313        }
 314
 315        if (!strcmp(var, "core.compression")) {
 316                int level = git_config_int(var, value);
 317                if (level == -1)
 318                        level = Z_DEFAULT_COMPRESSION;
 319                else if (level < 0 || level > Z_BEST_COMPRESSION)
 320                        die("bad zlib compression level %d", level);
 321                core_compression_level = level;
 322                core_compression_seen = 1;
 323                if (!zlib_compression_seen)
 324                        zlib_compression_level = level;
 325                return 0;
 326        }
 327
 328        if (!strcmp(var, "core.packedgitwindowsize")) {
 329                int pgsz_x2 = getpagesize() * 2;
 330                packed_git_window_size = git_config_int(var, value);
 331
 332                /* This value must be multiple of (pagesize * 2) */
 333                packed_git_window_size /= pgsz_x2;
 334                if (packed_git_window_size < 1)
 335                        packed_git_window_size = 1;
 336                packed_git_window_size *= pgsz_x2;
 337                return 0;
 338        }
 339
 340        if (!strcmp(var, "core.packedgitlimit")) {
 341                packed_git_limit = git_config_int(var, value);
 342                return 0;
 343        }
 344
 345        if (!strcmp(var, "core.deltabasecachelimit")) {
 346                delta_base_cache_limit = git_config_int(var, value);
 347                return 0;
 348        }
 349
 350        if (!strcmp(var, "core.autocrlf")) {
 351                if (value && !strcasecmp(value, "input")) {
 352                        auto_crlf = -1;
 353                        return 0;
 354                }
 355                auto_crlf = git_config_bool(var, value);
 356                return 0;
 357        }
 358
 359        if (!strcmp(var, "user.name")) {
 360                strlcpy(git_default_name, value, sizeof(git_default_name));
 361                return 0;
 362        }
 363
 364        if (!strcmp(var, "user.email")) {
 365                strlcpy(git_default_email, value, sizeof(git_default_email));
 366                return 0;
 367        }
 368
 369        if (!strcmp(var, "i18n.commitencoding")) {
 370                git_commit_encoding = xstrdup(value);
 371                return 0;
 372        }
 373
 374        if (!strcmp(var, "i18n.logoutputencoding")) {
 375                git_log_output_encoding = xstrdup(value);
 376                return 0;
 377        }
 378
 379
 380        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 381                pager_use_color = git_config_bool(var,value);
 382                return 0;
 383        }
 384
 385        /* Add other config variables here and to Documentation/config.txt. */
 386        return 0;
 387}
 388
 389int git_config_from_file(config_fn_t fn, const char *filename)
 390{
 391        int ret;
 392        FILE *f = fopen(filename, "r");
 393
 394        ret = -1;
 395        if (f) {
 396                config_file = f;
 397                config_file_name = filename;
 398                config_linenr = 1;
 399                ret = git_parse_file(fn);
 400                fclose(f);
 401                config_file_name = NULL;
 402        }
 403        return ret;
 404}
 405
 406int git_config(config_fn_t fn)
 407{
 408        int ret = 0;
 409        char *repo_config = NULL;
 410        const char *home = NULL, *filename;
 411
 412        /* $GIT_CONFIG makes git read _only_ the given config file,
 413         * $GIT_CONFIG_LOCAL will make it process it in addition to the
 414         * global config file, the same way it would the per-repository
 415         * config file otherwise. */
 416        filename = getenv(CONFIG_ENVIRONMENT);
 417        if (!filename) {
 418                if (!access(ETC_GITCONFIG, R_OK))
 419                        ret += git_config_from_file(fn, ETC_GITCONFIG);
 420                home = getenv("HOME");
 421                filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 422                if (!filename)
 423                        filename = repo_config = xstrdup(git_path("config"));
 424        }
 425
 426        if (home) {
 427                char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 428                if (!access(user_config, R_OK))
 429                        ret = git_config_from_file(fn, user_config);
 430                free(user_config);
 431        }
 432
 433        ret += git_config_from_file(fn, filename);
 434        free(repo_config);
 435        return ret;
 436}
 437
 438/*
 439 * Find all the stuff for git_config_set() below.
 440 */
 441
 442#define MAX_MATCHES 512
 443
 444static struct {
 445        int baselen;
 446        char* key;
 447        int do_not_match;
 448        regex_t* value_regex;
 449        int multi_replace;
 450        size_t offset[MAX_MATCHES];
 451        enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 452        int seen;
 453} store;
 454
 455static int matches(const char* key, const char* value)
 456{
 457        return !strcmp(key, store.key) &&
 458                (store.value_regex == NULL ||
 459                 (store.do_not_match ^
 460                  !regexec(store.value_regex, value, 0, NULL, 0)));
 461}
 462
 463static int store_aux(const char* key, const char* value)
 464{
 465        const char *ep;
 466        size_t section_len;
 467
 468        switch (store.state) {
 469        case KEY_SEEN:
 470                if (matches(key, value)) {
 471                        if (store.seen == 1 && store.multi_replace == 0) {
 472                                fprintf(stderr,
 473                                        "Warning: %s has multiple values\n",
 474                                        key);
 475                        } else if (store.seen >= MAX_MATCHES) {
 476                                fprintf(stderr, "Too many matches\n");
 477                                return 1;
 478                        }
 479
 480                        store.offset[store.seen] = ftell(config_file);
 481                        store.seen++;
 482                }
 483                break;
 484        case SECTION_SEEN:
 485                /*
 486                 * What we are looking for is in store.key (both
 487                 * section and var), and its section part is baselen
 488                 * long.  We found key (again, both section and var).
 489                 * We would want to know if this key is in the same
 490                 * section as what we are looking for.  We already
 491                 * know we are in the same section as what should
 492                 * hold store.key.
 493                 */
 494                ep = strrchr(key, '.');
 495                section_len = ep - key;
 496
 497                if ((section_len != store.baselen) ||
 498                    memcmp(key, store.key, section_len+1)) {
 499                        store.state = SECTION_END_SEEN;
 500                        break;
 501                }
 502
 503                /*
 504                 * Do not increment matches: this is no match, but we
 505                 * just made sure we are in the desired section.
 506                 */
 507                store.offset[store.seen] = ftell(config_file);
 508                /* fallthru */
 509        case SECTION_END_SEEN:
 510        case START:
 511                if (matches(key, value)) {
 512                        store.offset[store.seen] = ftell(config_file);
 513                        store.state = KEY_SEEN;
 514                        store.seen++;
 515                } else {
 516                        if (strrchr(key, '.') - key == store.baselen &&
 517                              !strncmp(key, store.key, store.baselen)) {
 518                                        store.state = SECTION_SEEN;
 519                                        store.offset[store.seen] = ftell(config_file);
 520                        }
 521                }
 522        }
 523        return 0;
 524}
 525
 526static int write_error()
 527{
 528        fprintf(stderr, "Failed to write new configuration file\n");
 529
 530        /* Same error code as "failed to rename". */
 531        return 4;
 532}
 533
 534static int store_write_section(int fd, const char* key)
 535{
 536        const char *dot = strchr(key, '.');
 537        int len1 = store.baselen, len2 = -1;
 538
 539        dot = strchr(key, '.');
 540        if (dot) {
 541                int dotlen = dot - key;
 542                if (dotlen < len1) {
 543                        len2 = len1 - dotlen - 1;
 544                        len1 = dotlen;
 545                }
 546        }
 547
 548        if (write_in_full(fd, "[", 1) != 1 ||
 549            write_in_full(fd, key, len1) != len1)
 550                return 0;
 551        if (len2 >= 0) {
 552                if (write_in_full(fd, " \"", 2) != 2)
 553                        return 0;
 554                while (--len2 >= 0) {
 555                        unsigned char c = *++dot;
 556                        if (c == '"')
 557                                if (write_in_full(fd, "\\", 1) != 1)
 558                                        return 0;
 559                        if (write_in_full(fd, &c, 1) != 1)
 560                                return 0;
 561                }
 562                if (write_in_full(fd, "\"", 1) != 1)
 563                        return 0;
 564        }
 565        if (write_in_full(fd, "]\n", 2) != 2)
 566                return 0;
 567
 568        return 1;
 569}
 570
 571static int store_write_pair(int fd, const char* key, const char* value)
 572{
 573        int i;
 574        int length = strlen(key+store.baselen+1);
 575        int quote = 0;
 576
 577        /* Check to see if the value needs to be quoted. */
 578        if (value[0] == ' ')
 579                quote = 1;
 580        for (i = 0; value[i]; i++)
 581                if (value[i] == ';' || value[i] == '#')
 582                        quote = 1;
 583        if (value[i-1] == ' ')
 584                quote = 1;
 585
 586        if (write_in_full(fd, "\t", 1) != 1 ||
 587            write_in_full(fd, key+store.baselen+1, length) != length ||
 588            write_in_full(fd, " = ", 3) != 3)
 589                return 0;
 590        if (quote && write_in_full(fd, "\"", 1) != 1)
 591                return 0;
 592        for (i = 0; value[i]; i++)
 593                switch (value[i]) {
 594                case '\n':
 595                        if (write_in_full(fd, "\\n", 2) != 2)
 596                                return 0;
 597                        break;
 598                case '\t':
 599                        if (write_in_full(fd, "\\t", 2) != 2)
 600                                return 0;
 601                        break;
 602                case '"':
 603                case '\\':
 604                        if (write_in_full(fd, "\\", 1) != 1)
 605                                return 0;
 606                default:
 607                        if (write_in_full(fd, value+i, 1) != 1)
 608                                return 0;
 609                        break;
 610                }
 611        if (quote && write_in_full(fd, "\"", 1) != 1)
 612                return 0;
 613        if (write_in_full(fd, "\n", 1) != 1)
 614                return 0;
 615        return 1;
 616}
 617
 618static ssize_t find_beginning_of_line(const char* contents, size_t size,
 619        size_t offset_, int* found_bracket)
 620{
 621        size_t equal_offset = size, bracket_offset = size;
 622        ssize_t offset;
 623
 624        for (offset = offset_-2; offset > 0
 625                        && contents[offset] != '\n'; offset--)
 626                switch (contents[offset]) {
 627                        case '=': equal_offset = offset; break;
 628                        case ']': bracket_offset = offset; break;
 629                }
 630        if (bracket_offset < equal_offset) {
 631                *found_bracket = 1;
 632                offset = bracket_offset+1;
 633        } else
 634                offset++;
 635
 636        return offset;
 637}
 638
 639int git_config_set(const char* key, const char* value)
 640{
 641        return git_config_set_multivar(key, value, NULL, 0);
 642}
 643
 644/*
 645 * If value==NULL, unset in (remove from) config,
 646 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 647 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 648 *     else all matching key/values (regardless how many) are removed,
 649 *     before the new pair is written.
 650 *
 651 * Returns 0 on success.
 652 *
 653 * This function does this:
 654 *
 655 * - it locks the config file by creating ".git/config.lock"
 656 *
 657 * - it then parses the config using store_aux() as validator to find
 658 *   the position on the key/value pair to replace. If it is to be unset,
 659 *   it must be found exactly once.
 660 *
 661 * - the config file is mmap()ed and the part before the match (if any) is
 662 *   written to the lock file, then the changed part and the rest.
 663 *
 664 * - the config file is removed and the lock file rename()d to it.
 665 *
 666 */
 667int git_config_set_multivar(const char* key, const char* value,
 668        const char* value_regex, int multi_replace)
 669{
 670        int i, dot;
 671        int fd = -1, in_fd;
 672        int ret;
 673        char* config_filename;
 674        char* lock_file;
 675        const char* last_dot = strrchr(key, '.');
 676
 677        config_filename = getenv(CONFIG_ENVIRONMENT);
 678        if (!config_filename) {
 679                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 680                if (!config_filename)
 681                        config_filename  = git_path("config");
 682        }
 683        config_filename = xstrdup(config_filename);
 684        lock_file = xstrdup(mkpath("%s.lock", config_filename));
 685
 686        /*
 687         * Since "key" actually contains the section name and the real
 688         * key name separated by a dot, we have to know where the dot is.
 689         */
 690
 691        if (last_dot == NULL) {
 692                fprintf(stderr, "key does not contain a section: %s\n", key);
 693                ret = 2;
 694                goto out_free;
 695        }
 696        store.baselen = last_dot - key;
 697
 698        store.multi_replace = multi_replace;
 699
 700        /*
 701         * Validate the key and while at it, lower case it for matching.
 702         */
 703        store.key = xmalloc(strlen(key) + 1);
 704        dot = 0;
 705        for (i = 0; key[i]; i++) {
 706                unsigned char c = key[i];
 707                if (c == '.')
 708                        dot = 1;
 709                /* Leave the extended basename untouched.. */
 710                if (!dot || i > store.baselen) {
 711                        if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 712                                fprintf(stderr, "invalid key: %s\n", key);
 713                                free(store.key);
 714                                ret = 1;
 715                                goto out_free;
 716                        }
 717                        c = tolower(c);
 718                } else if (c == '\n') {
 719                        fprintf(stderr, "invalid key (newline): %s\n", key);
 720                        free(store.key);
 721                        ret = 1;
 722                        goto out_free;
 723                }
 724                store.key[i] = c;
 725        }
 726        store.key[i] = 0;
 727
 728        /*
 729         * The lock_file serves a purpose in addition to locking: the new
 730         * contents of .git/config will be written into it.
 731         */
 732        fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 733        if (fd < 0 || adjust_shared_perm(lock_file)) {
 734                fprintf(stderr, "could not lock config file\n");
 735                free(store.key);
 736                ret = -1;
 737                goto out_free;
 738        }
 739
 740        /*
 741         * If .git/config does not exist yet, write a minimal version.
 742         */
 743        in_fd = open(config_filename, O_RDONLY);
 744        if ( in_fd < 0 ) {
 745                free(store.key);
 746
 747                if ( ENOENT != errno ) {
 748                        error("opening %s: %s", config_filename,
 749                              strerror(errno));
 750                        ret = 3; /* same as "invalid config file" */
 751                        goto out_free;
 752                }
 753                /* if nothing to unset, error out */
 754                if (value == NULL) {
 755                        ret = 5;
 756                        goto out_free;
 757                }
 758
 759                store.key = (char*)key;
 760                if (!store_write_section(fd, key) ||
 761                    !store_write_pair(fd, key, value))
 762                        goto write_err_out;
 763        } else {
 764                struct stat st;
 765                char* contents;
 766                size_t contents_sz, copy_begin, copy_end;
 767                int i, new_line = 0;
 768
 769                if (value_regex == NULL)
 770                        store.value_regex = NULL;
 771                else {
 772                        if (value_regex[0] == '!') {
 773                                store.do_not_match = 1;
 774                                value_regex++;
 775                        } else
 776                                store.do_not_match = 0;
 777
 778                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 779                        if (regcomp(store.value_regex, value_regex,
 780                                        REG_EXTENDED)) {
 781                                fprintf(stderr, "Invalid pattern: %s\n",
 782                                        value_regex);
 783                                free(store.value_regex);
 784                                ret = 6;
 785                                goto out_free;
 786                        }
 787                }
 788
 789                store.offset[0] = 0;
 790                store.state = START;
 791                store.seen = 0;
 792
 793                /*
 794                 * After this, store.offset will contain the *end* offset
 795                 * of the last match, or remain at 0 if no match was found.
 796                 * As a side effect, we make sure to transform only a valid
 797                 * existing config file.
 798                 */
 799                if (git_config_from_file(store_aux, config_filename)) {
 800                        fprintf(stderr, "invalid config file\n");
 801                        free(store.key);
 802                        if (store.value_regex != NULL) {
 803                                regfree(store.value_regex);
 804                                free(store.value_regex);
 805                        }
 806                        ret = 3;
 807                        goto out_free;
 808                }
 809
 810                free(store.key);
 811                if (store.value_regex != NULL) {
 812                        regfree(store.value_regex);
 813                        free(store.value_regex);
 814                }
 815
 816                /* if nothing to unset, or too many matches, error out */
 817                if ((store.seen == 0 && value == NULL) ||
 818                                (store.seen > 1 && multi_replace == 0)) {
 819                        ret = 5;
 820                        goto out_free;
 821                }
 822
 823                fstat(in_fd, &st);
 824                contents_sz = xsize_t(st.st_size);
 825                contents = xmmap(NULL, contents_sz, PROT_READ,
 826                        MAP_PRIVATE, in_fd, 0);
 827                close(in_fd);
 828
 829                if (store.seen == 0)
 830                        store.seen = 1;
 831
 832                for (i = 0, copy_begin = 0; i < store.seen; i++) {
 833                        if (store.offset[i] == 0) {
 834                                store.offset[i] = copy_end = contents_sz;
 835                        } else if (store.state != KEY_SEEN) {
 836                                copy_end = store.offset[i];
 837                        } else
 838                                copy_end = find_beginning_of_line(
 839                                        contents, contents_sz,
 840                                        store.offset[i]-2, &new_line);
 841
 842                        /* write the first part of the config */
 843                        if (copy_end > copy_begin) {
 844                                if (write_in_full(fd, contents + copy_begin,
 845                                                  copy_end - copy_begin) <
 846                                    copy_end - copy_begin)
 847                                        goto write_err_out;
 848                                if (new_line &&
 849                                    write_in_full(fd, "\n", 1) != 1)
 850                                        goto write_err_out;
 851                        }
 852                        copy_begin = store.offset[i];
 853                }
 854
 855                /* write the pair (value == NULL means unset) */
 856                if (value != NULL) {
 857                        if (store.state == START) {
 858                                if (!store_write_section(fd, key))
 859                                        goto write_err_out;
 860                        }
 861                        if (!store_write_pair(fd, key, value))
 862                                goto write_err_out;
 863                }
 864
 865                /* write the rest of the config */
 866                if (copy_begin < contents_sz)
 867                        if (write_in_full(fd, contents + copy_begin,
 868                                          contents_sz - copy_begin) <
 869                            contents_sz - copy_begin)
 870                                goto write_err_out;
 871
 872                munmap(contents, contents_sz);
 873                unlink(config_filename);
 874        }
 875
 876        if (rename(lock_file, config_filename) < 0) {
 877                fprintf(stderr, "Could not rename the lock file?\n");
 878                ret = 4;
 879                goto out_free;
 880        }
 881
 882        ret = 0;
 883
 884out_free:
 885        if (0 <= fd)
 886                close(fd);
 887        free(config_filename);
 888        if (lock_file) {
 889                unlink(lock_file);
 890                free(lock_file);
 891        }
 892        return ret;
 893
 894write_err_out:
 895        ret = write_error();
 896        goto out_free;
 897
 898}
 899
 900static int section_name_match (const char *buf, const char *name)
 901{
 902        int i = 0, j = 0, dot = 0;
 903        for (; buf[i] && buf[i] != ']'; i++) {
 904                if (!dot && isspace(buf[i])) {
 905                        dot = 1;
 906                        if (name[j++] != '.')
 907                                break;
 908                        for (i++; isspace(buf[i]); i++)
 909                                ; /* do nothing */
 910                        if (buf[i] != '"')
 911                                break;
 912                        continue;
 913                }
 914                if (buf[i] == '\\' && dot)
 915                        i++;
 916                else if (buf[i] == '"' && dot) {
 917                        for (i++; isspace(buf[i]); i++)
 918                                ; /* do_nothing */
 919                        break;
 920                }
 921                if (buf[i] != name[j++])
 922                        break;
 923        }
 924        return (buf[i] == ']' && name[j] == 0);
 925}
 926
 927/* if new_name == NULL, the section is removed instead */
 928int git_config_rename_section(const char *old_name, const char *new_name)
 929{
 930        int ret = 0, remove = 0;
 931        char *config_filename;
 932        struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 933        int out_fd;
 934        char buf[1024];
 935
 936        config_filename = getenv(CONFIG_ENVIRONMENT);
 937        if (!config_filename) {
 938                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 939                if (!config_filename)
 940                        config_filename  = git_path("config");
 941        }
 942        config_filename = xstrdup(config_filename);
 943        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 944        if (out_fd < 0) {
 945                ret = error("Could not lock config file!");
 946                goto out;
 947        }
 948
 949        if (!(config_file = fopen(config_filename, "rb"))) {
 950                /* no config file means nothing to rename, no error */
 951                goto unlock_and_out;
 952        }
 953
 954        while (fgets(buf, sizeof(buf), config_file)) {
 955                int i;
 956                int length;
 957                for (i = 0; buf[i] && isspace(buf[i]); i++)
 958                        ; /* do nothing */
 959                if (buf[i] == '[') {
 960                        /* it's a section */
 961                        if (section_name_match (&buf[i+1], old_name)) {
 962                                ret++;
 963                                if (new_name == NULL) {
 964                                        remove = 1;
 965                                        continue;
 966                                }
 967                                store.baselen = strlen(new_name);
 968                                if (!store_write_section(out_fd, new_name)) {
 969                                        ret = write_error();
 970                                        goto out;
 971                                }
 972                                continue;
 973                        }
 974                        remove = 0;
 975                }
 976                if (remove)
 977                        continue;
 978                length = strlen(buf);
 979                if (write_in_full(out_fd, buf, length) != length) {
 980                        ret = write_error();
 981                        goto out;
 982                }
 983        }
 984        fclose(config_file);
 985 unlock_and_out:
 986        if (close(out_fd) || commit_lock_file(lock) < 0)
 987                        ret = error("Cannot commit config file!");
 988 out:
 989        free(config_filename);
 990        return ret;
 991}