Andrew's git / gitweb.git / config.c
?
config.con commit git-diff: turn on recursion by default (82cb8af)
   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
 236static unsigned long get_unit_factor(const char *end)
 237{
 238        if (!*end)
 239                return 1;
 240        else if (!strcasecmp(end, "k"))
 241                return 1024;
 242        else if (!strcasecmp(end, "m"))
 243                return 1024 * 1024;
 244        else if (!strcasecmp(end, "g"))
 245                return 1024 * 1024 * 1024;
 246        die("unknown unit: '%s'", end);
 247}
 248
 249int git_parse_long(const char *value, long *ret)
 250{
 251        if (value && *value) {
 252                char *end;
 253                long val = strtol(value, &end, 0);
 254                *ret = val * get_unit_factor(end);
 255                return 1;
 256        }
 257        return 0;
 258}
 259
 260int git_parse_ulong(const char *value, unsigned long *ret)
 261{
 262        if (value && *value) {
 263                char *end;
 264                unsigned long val = strtoul(value, &end, 0);
 265                *ret = val * get_unit_factor(end);
 266                return 1;
 267        }
 268        return 0;
 269}
 270
 271int git_config_int(const char *name, const char *value)
 272{
 273        long ret;
 274        if (!git_parse_long(value, &ret))
 275                die("bad config value for '%s' in %s", name, config_file_name);
 276        return ret;
 277}
 278
 279unsigned long git_config_ulong(const char *name, const char *value)
 280{
 281        unsigned long ret;
 282        if (!git_parse_ulong(value, &ret))
 283                die("bad config value for '%s' in %s", name, config_file_name);
 284        return ret;
 285}
 286
 287int git_config_bool(const char *name, const char *value)
 288{
 289        if (!value)
 290                return 1;
 291        if (!*value)
 292                return 0;
 293        if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 294                return 1;
 295        if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 296                return 0;
 297        return git_config_int(name, value) != 0;
 298}
 299
 300int git_default_config(const char *var, const char *value)
 301{
 302        /* This needs a better name */
 303        if (!strcmp(var, "core.filemode")) {
 304                trust_executable_bit = git_config_bool(var, value);
 305                return 0;
 306        }
 307
 308        if (!strcmp(var, "core.quotepath")) {
 309                quote_path_fully = git_config_bool(var, value);
 310                return 0;
 311        }
 312
 313        if (!strcmp(var, "core.symlinks")) {
 314                has_symlinks = git_config_bool(var, value);
 315                return 0;
 316        }
 317
 318        if (!strcmp(var, "core.bare")) {
 319                is_bare_repository_cfg = git_config_bool(var, value);
 320                return 0;
 321        }
 322
 323        if (!strcmp(var, "core.ignorestat")) {
 324                assume_unchanged = git_config_bool(var, value);
 325                return 0;
 326        }
 327
 328        if (!strcmp(var, "core.prefersymlinkrefs")) {
 329                prefer_symlink_refs = git_config_bool(var, value);
 330                return 0;
 331        }
 332
 333        if (!strcmp(var, "core.logallrefupdates")) {
 334                log_all_ref_updates = git_config_bool(var, value);
 335                return 0;
 336        }
 337
 338        if (!strcmp(var, "core.warnambiguousrefs")) {
 339                warn_ambiguous_refs = git_config_bool(var, value);
 340                return 0;
 341        }
 342
 343        if (!strcmp(var, "core.loosecompression")) {
 344                int level = git_config_int(var, value);
 345                if (level == -1)
 346                        level = Z_DEFAULT_COMPRESSION;
 347                else if (level < 0 || level > Z_BEST_COMPRESSION)
 348                        die("bad zlib compression level %d", level);
 349                zlib_compression_level = level;
 350                zlib_compression_seen = 1;
 351                return 0;
 352        }
 353
 354        if (!strcmp(var, "core.compression")) {
 355                int level = git_config_int(var, value);
 356                if (level == -1)
 357                        level = Z_DEFAULT_COMPRESSION;
 358                else if (level < 0 || level > Z_BEST_COMPRESSION)
 359                        die("bad zlib compression level %d", level);
 360                core_compression_level = level;
 361                core_compression_seen = 1;
 362                if (!zlib_compression_seen)
 363                        zlib_compression_level = level;
 364                return 0;
 365        }
 366
 367        if (!strcmp(var, "core.packedgitwindowsize")) {
 368                int pgsz_x2 = getpagesize() * 2;
 369                packed_git_window_size = git_config_int(var, value);
 370
 371                /* This value must be multiple of (pagesize * 2) */
 372                packed_git_window_size /= pgsz_x2;
 373                if (packed_git_window_size < 1)
 374                        packed_git_window_size = 1;
 375                packed_git_window_size *= pgsz_x2;
 376                return 0;
 377        }
 378
 379        if (!strcmp(var, "core.packedgitlimit")) {
 380                packed_git_limit = git_config_int(var, value);
 381                return 0;
 382        }
 383
 384        if (!strcmp(var, "core.deltabasecachelimit")) {
 385                delta_base_cache_limit = git_config_int(var, value);
 386                return 0;
 387        }
 388
 389        if (!strcmp(var, "core.autocrlf")) {
 390                if (value && !strcasecmp(value, "input")) {
 391                        auto_crlf = -1;
 392                        return 0;
 393                }
 394                auto_crlf = git_config_bool(var, value);
 395                return 0;
 396        }
 397
 398        if (!strcmp(var, "user.name")) {
 399                strlcpy(git_default_name, value, sizeof(git_default_name));
 400                return 0;
 401        }
 402
 403        if (!strcmp(var, "user.email")) {
 404                strlcpy(git_default_email, value, sizeof(git_default_email));
 405                return 0;
 406        }
 407
 408        if (!strcmp(var, "i18n.commitencoding")) {
 409                git_commit_encoding = xstrdup(value);
 410                return 0;
 411        }
 412
 413        if (!strcmp(var, "i18n.logoutputencoding")) {
 414                git_log_output_encoding = xstrdup(value);
 415                return 0;
 416        }
 417
 418
 419        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 420                pager_use_color = git_config_bool(var,value);
 421                return 0;
 422        }
 423
 424        if (!strcmp(var, "core.pager")) {
 425                pager_program = xstrdup(value);
 426                return 0;
 427        }
 428
 429        /* Add other config variables here and to Documentation/config.txt. */
 430        return 0;
 431}
 432
 433int git_config_from_file(config_fn_t fn, const char *filename)
 434{
 435        int ret;
 436        FILE *f = fopen(filename, "r");
 437
 438        ret = -1;
 439        if (f) {
 440                config_file = f;
 441                config_file_name = filename;
 442                config_linenr = 1;
 443                ret = git_parse_file(fn);
 444                fclose(f);
 445                config_file_name = NULL;
 446        }
 447        return ret;
 448}
 449
 450int git_config(config_fn_t fn)
 451{
 452        int ret = 0;
 453        char *repo_config = NULL;
 454        const char *home = NULL, *filename;
 455
 456        /* $GIT_CONFIG makes git read _only_ the given config file,
 457         * $GIT_CONFIG_LOCAL will make it process it in addition to the
 458         * global config file, the same way it would the per-repository
 459         * config file otherwise. */
 460        filename = getenv(CONFIG_ENVIRONMENT);
 461        if (!filename) {
 462                if (!access(ETC_GITCONFIG, R_OK))
 463                        ret += git_config_from_file(fn, ETC_GITCONFIG);
 464                home = getenv("HOME");
 465                filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 466                if (!filename)
 467                        filename = repo_config = xstrdup(git_path("config"));
 468        }
 469
 470        if (home) {
 471                char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 472                if (!access(user_config, R_OK))
 473                        ret = git_config_from_file(fn, user_config);
 474                free(user_config);
 475        }
 476
 477        ret += git_config_from_file(fn, filename);
 478        free(repo_config);
 479        return ret;
 480}
 481
 482/*
 483 * Find all the stuff for git_config_set() below.
 484 */
 485
 486#define MAX_MATCHES 512
 487
 488static struct {
 489        int baselen;
 490        char* key;
 491        int do_not_match;
 492        regex_t* value_regex;
 493        int multi_replace;
 494        size_t offset[MAX_MATCHES];
 495        enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 496        int seen;
 497} store;
 498
 499static int matches(const char* key, const char* value)
 500{
 501        return !strcmp(key, store.key) &&
 502                (store.value_regex == NULL ||
 503                 (store.do_not_match ^
 504                  !regexec(store.value_regex, value, 0, NULL, 0)));
 505}
 506
 507static int store_aux(const char* key, const char* value)
 508{
 509        const char *ep;
 510        size_t section_len;
 511
 512        switch (store.state) {
 513        case KEY_SEEN:
 514                if (matches(key, value)) {
 515                        if (store.seen == 1 && store.multi_replace == 0) {
 516                                fprintf(stderr,
 517                                        "Warning: %s has multiple values\n",
 518                                        key);
 519                        } else if (store.seen >= MAX_MATCHES) {
 520                                fprintf(stderr, "Too many matches\n");
 521                                return 1;
 522                        }
 523
 524                        store.offset[store.seen] = ftell(config_file);
 525                        store.seen++;
 526                }
 527                break;
 528        case SECTION_SEEN:
 529                /*
 530                 * What we are looking for is in store.key (both
 531                 * section and var), and its section part is baselen
 532                 * long.  We found key (again, both section and var).
 533                 * We would want to know if this key is in the same
 534                 * section as what we are looking for.  We already
 535                 * know we are in the same section as what should
 536                 * hold store.key.
 537                 */
 538                ep = strrchr(key, '.');
 539                section_len = ep - key;
 540
 541                if ((section_len != store.baselen) ||
 542                    memcmp(key, store.key, section_len+1)) {
 543                        store.state = SECTION_END_SEEN;
 544                        break;
 545                }
 546
 547                /*
 548                 * Do not increment matches: this is no match, but we
 549                 * just made sure we are in the desired section.
 550                 */
 551                store.offset[store.seen] = ftell(config_file);
 552                /* fallthru */
 553        case SECTION_END_SEEN:
 554        case START:
 555                if (matches(key, value)) {
 556                        store.offset[store.seen] = ftell(config_file);
 557                        store.state = KEY_SEEN;
 558                        store.seen++;
 559                } else {
 560                        if (strrchr(key, '.') - key == store.baselen &&
 561                              !strncmp(key, store.key, store.baselen)) {
 562                                        store.state = SECTION_SEEN;
 563                                        store.offset[store.seen] = ftell(config_file);
 564                        }
 565                }
 566        }
 567        return 0;
 568}
 569
 570static int write_error(void)
 571{
 572        fprintf(stderr, "Failed to write new configuration file\n");
 573
 574        /* Same error code as "failed to rename". */
 575        return 4;
 576}
 577
 578static int store_write_section(int fd, const char* key)
 579{
 580        const char *dot = strchr(key, '.');
 581        int len1 = store.baselen, len2 = -1;
 582
 583        dot = strchr(key, '.');
 584        if (dot) {
 585                int dotlen = dot - key;
 586                if (dotlen < len1) {
 587                        len2 = len1 - dotlen - 1;
 588                        len1 = dotlen;
 589                }
 590        }
 591
 592        if (write_in_full(fd, "[", 1) != 1 ||
 593            write_in_full(fd, key, len1) != len1)
 594                return 0;
 595        if (len2 >= 0) {
 596                if (write_in_full(fd, " \"", 2) != 2)
 597                        return 0;
 598                while (--len2 >= 0) {
 599                        unsigned char c = *++dot;
 600                        if (c == '"')
 601                                if (write_in_full(fd, "\\", 1) != 1)
 602                                        return 0;
 603                        if (write_in_full(fd, &c, 1) != 1)
 604                                return 0;
 605                }
 606                if (write_in_full(fd, "\"", 1) != 1)
 607                        return 0;
 608        }
 609        if (write_in_full(fd, "]\n", 2) != 2)
 610                return 0;
 611
 612        return 1;
 613}
 614
 615static int store_write_pair(int fd, const char* key, const char* value)
 616{
 617        int i;
 618        int length = strlen(key+store.baselen+1);
 619        int quote = 0;
 620
 621        /* Check to see if the value needs to be quoted. */
 622        if (value[0] == ' ')
 623                quote = 1;
 624        for (i = 0; value[i]; i++)
 625                if (value[i] == ';' || value[i] == '#')
 626                        quote = 1;
 627        if (value[i-1] == ' ')
 628                quote = 1;
 629
 630        if (write_in_full(fd, "\t", 1) != 1 ||
 631            write_in_full(fd, key+store.baselen+1, length) != length ||
 632            write_in_full(fd, " = ", 3) != 3)
 633                return 0;
 634        if (quote && write_in_full(fd, "\"", 1) != 1)
 635                return 0;
 636        for (i = 0; value[i]; i++)
 637                switch (value[i]) {
 638                case '\n':
 639                        if (write_in_full(fd, "\\n", 2) != 2)
 640                                return 0;
 641                        break;
 642                case '\t':
 643                        if (write_in_full(fd, "\\t", 2) != 2)
 644                                return 0;
 645                        break;
 646                case '"':
 647                case '\\':
 648                        if (write_in_full(fd, "\\", 1) != 1)
 649                                return 0;
 650                default:
 651                        if (write_in_full(fd, value+i, 1) != 1)
 652                                return 0;
 653                        break;
 654                }
 655        if (quote && write_in_full(fd, "\"", 1) != 1)
 656                return 0;
 657        if (write_in_full(fd, "\n", 1) != 1)
 658                return 0;
 659        return 1;
 660}
 661
 662static ssize_t find_beginning_of_line(const char* contents, size_t size,
 663        size_t offset_, int* found_bracket)
 664{
 665        size_t equal_offset = size, bracket_offset = size;
 666        ssize_t offset;
 667
 668        for (offset = offset_-2; offset > 0
 669                        && contents[offset] != '\n'; offset--)
 670                switch (contents[offset]) {
 671                        case '=': equal_offset = offset; break;
 672                        case ']': bracket_offset = offset; break;
 673                }
 674        if (bracket_offset < equal_offset) {
 675                *found_bracket = 1;
 676                offset = bracket_offset+1;
 677        } else
 678                offset++;
 679
 680        return offset;
 681}
 682
 683int git_config_set(const char* key, const char* value)
 684{
 685        return git_config_set_multivar(key, value, NULL, 0);
 686}
 687
 688/*
 689 * If value==NULL, unset in (remove from) config,
 690 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 691 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 692 *     else all matching key/values (regardless how many) are removed,
 693 *     before the new pair is written.
 694 *
 695 * Returns 0 on success.
 696 *
 697 * This function does this:
 698 *
 699 * - it locks the config file by creating ".git/config.lock"
 700 *
 701 * - it then parses the config using store_aux() as validator to find
 702 *   the position on the key/value pair to replace. If it is to be unset,
 703 *   it must be found exactly once.
 704 *
 705 * - the config file is mmap()ed and the part before the match (if any) is
 706 *   written to the lock file, then the changed part and the rest.
 707 *
 708 * - the config file is removed and the lock file rename()d to it.
 709 *
 710 */
 711int git_config_set_multivar(const char* key, const char* value,
 712        const char* value_regex, int multi_replace)
 713{
 714        int i, dot;
 715        int fd = -1, in_fd;
 716        int ret;
 717        char* config_filename;
 718        char* lock_file;
 719        const char* last_dot = strrchr(key, '.');
 720
 721        config_filename = getenv(CONFIG_ENVIRONMENT);
 722        if (!config_filename) {
 723                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 724                if (!config_filename)
 725                        config_filename  = git_path("config");
 726        }
 727        config_filename = xstrdup(config_filename);
 728        lock_file = xstrdup(mkpath("%s.lock", config_filename));
 729
 730        /*
 731         * Since "key" actually contains the section name and the real
 732         * key name separated by a dot, we have to know where the dot is.
 733         */
 734
 735        if (last_dot == NULL) {
 736                fprintf(stderr, "key does not contain a section: %s\n", key);
 737                ret = 2;
 738                goto out_free;
 739        }
 740        store.baselen = last_dot - key;
 741
 742        store.multi_replace = multi_replace;
 743
 744        /*
 745         * Validate the key and while at it, lower case it for matching.
 746         */
 747        store.key = xmalloc(strlen(key) + 1);
 748        dot = 0;
 749        for (i = 0; key[i]; i++) {
 750                unsigned char c = key[i];
 751                if (c == '.')
 752                        dot = 1;
 753                /* Leave the extended basename untouched.. */
 754                if (!dot || i > store.baselen) {
 755                        if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 756                                fprintf(stderr, "invalid key: %s\n", key);
 757                                free(store.key);
 758                                ret = 1;
 759                                goto out_free;
 760                        }
 761                        c = tolower(c);
 762                } else if (c == '\n') {
 763                        fprintf(stderr, "invalid key (newline): %s\n", key);
 764                        free(store.key);
 765                        ret = 1;
 766                        goto out_free;
 767                }
 768                store.key[i] = c;
 769        }
 770        store.key[i] = 0;
 771
 772        /*
 773         * The lock_file serves a purpose in addition to locking: the new
 774         * contents of .git/config will be written into it.
 775         */
 776        fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 777        if (fd < 0 || adjust_shared_perm(lock_file)) {
 778                fprintf(stderr, "could not lock config file\n");
 779                free(store.key);
 780                ret = -1;
 781                goto out_free;
 782        }
 783
 784        /*
 785         * If .git/config does not exist yet, write a minimal version.
 786         */
 787        in_fd = open(config_filename, O_RDONLY);
 788        if ( in_fd < 0 ) {
 789                free(store.key);
 790
 791                if ( ENOENT != errno ) {
 792                        error("opening %s: %s", config_filename,
 793                              strerror(errno));
 794                        ret = 3; /* same as "invalid config file" */
 795                        goto out_free;
 796                }
 797                /* if nothing to unset, error out */
 798                if (value == NULL) {
 799                        ret = 5;
 800                        goto out_free;
 801                }
 802
 803                store.key = (char*)key;
 804                if (!store_write_section(fd, key) ||
 805                    !store_write_pair(fd, key, value))
 806                        goto write_err_out;
 807        } else {
 808                struct stat st;
 809                char* contents;
 810                size_t contents_sz, copy_begin, copy_end;
 811                int i, new_line = 0;
 812
 813                if (value_regex == NULL)
 814                        store.value_regex = NULL;
 815                else {
 816                        if (value_regex[0] == '!') {
 817                                store.do_not_match = 1;
 818                                value_regex++;
 819                        } else
 820                                store.do_not_match = 0;
 821
 822                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 823                        if (regcomp(store.value_regex, value_regex,
 824                                        REG_EXTENDED)) {
 825                                fprintf(stderr, "Invalid pattern: %s\n",
 826                                        value_regex);
 827                                free(store.value_regex);
 828                                ret = 6;
 829                                goto out_free;
 830                        }
 831                }
 832
 833                store.offset[0] = 0;
 834                store.state = START;
 835                store.seen = 0;
 836
 837                /*
 838                 * After this, store.offset will contain the *end* offset
 839                 * of the last match, or remain at 0 if no match was found.
 840                 * As a side effect, we make sure to transform only a valid
 841                 * existing config file.
 842                 */
 843                if (git_config_from_file(store_aux, config_filename)) {
 844                        fprintf(stderr, "invalid config file\n");
 845                        free(store.key);
 846                        if (store.value_regex != NULL) {
 847                                regfree(store.value_regex);
 848                                free(store.value_regex);
 849                        }
 850                        ret = 3;
 851                        goto out_free;
 852                }
 853
 854                free(store.key);
 855                if (store.value_regex != NULL) {
 856                        regfree(store.value_regex);
 857                        free(store.value_regex);
 858                }
 859
 860                /* if nothing to unset, or too many matches, error out */
 861                if ((store.seen == 0 && value == NULL) ||
 862                                (store.seen > 1 && multi_replace == 0)) {
 863                        ret = 5;
 864                        goto out_free;
 865                }
 866
 867                fstat(in_fd, &st);
 868                contents_sz = xsize_t(st.st_size);
 869                contents = xmmap(NULL, contents_sz, PROT_READ,
 870                        MAP_PRIVATE, in_fd, 0);
 871                close(in_fd);
 872
 873                if (store.seen == 0)
 874                        store.seen = 1;
 875
 876                for (i = 0, copy_begin = 0; i < store.seen; i++) {
 877                        if (store.offset[i] == 0) {
 878                                store.offset[i] = copy_end = contents_sz;
 879                        } else if (store.state != KEY_SEEN) {
 880                                copy_end = store.offset[i];
 881                        } else
 882                                copy_end = find_beginning_of_line(
 883                                        contents, contents_sz,
 884                                        store.offset[i]-2, &new_line);
 885
 886                        /* write the first part of the config */
 887                        if (copy_end > copy_begin) {
 888                                if (write_in_full(fd, contents + copy_begin,
 889                                                  copy_end - copy_begin) <
 890                                    copy_end - copy_begin)
 891                                        goto write_err_out;
 892                                if (new_line &&
 893                                    write_in_full(fd, "\n", 1) != 1)
 894                                        goto write_err_out;
 895                        }
 896                        copy_begin = store.offset[i];
 897                }
 898
 899                /* write the pair (value == NULL means unset) */
 900                if (value != NULL) {
 901                        if (store.state == START) {
 902                                if (!store_write_section(fd, key))
 903                                        goto write_err_out;
 904                        }
 905                        if (!store_write_pair(fd, key, value))
 906                                goto write_err_out;
 907                }
 908
 909                /* write the rest of the config */
 910                if (copy_begin < contents_sz)
 911                        if (write_in_full(fd, contents + copy_begin,
 912                                          contents_sz - copy_begin) <
 913                            contents_sz - copy_begin)
 914                                goto write_err_out;
 915
 916                munmap(contents, contents_sz);
 917                unlink(config_filename);
 918        }
 919
 920        if (rename(lock_file, config_filename) < 0) {
 921                fprintf(stderr, "Could not rename the lock file?\n");
 922                ret = 4;
 923                goto out_free;
 924        }
 925
 926        ret = 0;
 927
 928out_free:
 929        if (0 <= fd)
 930                close(fd);
 931        free(config_filename);
 932        if (lock_file) {
 933                unlink(lock_file);
 934                free(lock_file);
 935        }
 936        return ret;
 937
 938write_err_out:
 939        ret = write_error();
 940        goto out_free;
 941
 942}
 943
 944static int section_name_match (const char *buf, const char *name)
 945{
 946        int i = 0, j = 0, dot = 0;
 947        for (; buf[i] && buf[i] != ']'; i++) {
 948                if (!dot && isspace(buf[i])) {
 949                        dot = 1;
 950                        if (name[j++] != '.')
 951                                break;
 952                        for (i++; isspace(buf[i]); i++)
 953                                ; /* do nothing */
 954                        if (buf[i] != '"')
 955                                break;
 956                        continue;
 957                }
 958                if (buf[i] == '\\' && dot)
 959                        i++;
 960                else if (buf[i] == '"' && dot) {
 961                        for (i++; isspace(buf[i]); i++)
 962                                ; /* do_nothing */
 963                        break;
 964                }
 965                if (buf[i] != name[j++])
 966                        break;
 967        }
 968        return (buf[i] == ']' && name[j] == 0);
 969}
 970
 971/* if new_name == NULL, the section is removed instead */
 972int git_config_rename_section(const char *old_name, const char *new_name)
 973{
 974        int ret = 0, remove = 0;
 975        char *config_filename;
 976        struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 977        int out_fd;
 978        char buf[1024];
 979
 980        config_filename = getenv(CONFIG_ENVIRONMENT);
 981        if (!config_filename) {
 982                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 983                if (!config_filename)
 984                        config_filename  = git_path("config");
 985        }
 986        config_filename = xstrdup(config_filename);
 987        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 988        if (out_fd < 0) {
 989                ret = error("Could not lock config file!");
 990                goto out;
 991        }
 992
 993        if (!(config_file = fopen(config_filename, "rb"))) {
 994                /* no config file means nothing to rename, no error */
 995                goto unlock_and_out;
 996        }
 997
 998        while (fgets(buf, sizeof(buf), config_file)) {
 999                int i;
1000                int length;
1001                for (i = 0; buf[i] && isspace(buf[i]); i++)
1002                        ; /* do nothing */
1003                if (buf[i] == '[') {
1004                        /* it's a section */
1005                        if (section_name_match (&buf[i+1], old_name)) {
1006                                ret++;
1007                                if (new_name == NULL) {
1008                                        remove = 1;
1009                                        continue;
1010                                }
1011                                store.baselen = strlen(new_name);
1012                                if (!store_write_section(out_fd, new_name)) {
1013                                        ret = write_error();
1014                                        goto out;
1015                                }
1016                                continue;
1017                        }
1018                        remove = 0;
1019                }
1020                if (remove)
1021                        continue;
1022                length = strlen(buf);
1023                if (write_in_full(out_fd, buf, length) != length) {
1024                        ret = write_error();
1025                        goto out;
1026                }
1027        }
1028        fclose(config_file);
1029 unlock_and_out:
1030        if (close(out_fd) || commit_lock_file(lock) < 0)
1031                        ret = error("Cannot commit config file!");
1032 out:
1033        free(config_filename);
1034        return ret;
1035}