Andrew's git / gitweb.git / config.c
?
config.con commit Evil Merge branch 'jc/status' (early part) into js/diff-ni (efdfd6c)
   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 get_next_char(void)
  16{
  17        int c;
  18        FILE *f;
  19
  20        c = '\n';
  21        if ((f = config_file) != NULL) {
  22                c = fgetc(f);
  23                if (c == '\r') {
  24                        /* DOS like systems */
  25                        c = fgetc(f);
  26                        if (c != '\n') {
  27                                ungetc(c, f);
  28                                c = '\r';
  29                        }
  30                }
  31                if (c == '\n')
  32                        config_linenr++;
  33                if (c == EOF) {
  34                        config_file = NULL;
  35                        c = '\n';
  36                }
  37        }
  38        return c;
  39}
  40
  41static char *parse_value(void)
  42{
  43        static char value[1024];
  44        int quote = 0, comment = 0, len = 0, space = 0;
  45
  46        for (;;) {
  47                int c = get_next_char();
  48                if (len >= sizeof(value))
  49                        return NULL;
  50                if (c == '\n') {
  51                        if (quote)
  52                                return NULL;
  53                        value[len] = 0;
  54                        return value;
  55                }
  56                if (comment)
  57                        continue;
  58                if (isspace(c) && !quote) {
  59                        space = 1;
  60                        continue;
  61                }
  62                if (!quote) {
  63                        if (c == ';' || c == '#') {
  64                                comment = 1;
  65                                continue;
  66                        }
  67                }
  68                if (space) {
  69                        if (len)
  70                                value[len++] = ' ';
  71                        space = 0;
  72                }
  73                if (c == '\\') {
  74                        c = get_next_char();
  75                        switch (c) {
  76                        case '\n':
  77                                continue;
  78                        case 't':
  79                                c = '\t';
  80                                break;
  81                        case 'b':
  82                                c = '\b';
  83                                break;
  84                        case 'n':
  85                                c = '\n';
  86                                break;
  87                        /* Some characters escape as themselves */
  88                        case '\\': case '"':
  89                                break;
  90                        /* Reject unknown escape sequences */
  91                        default:
  92                                return NULL;
  93                        }
  94                        value[len++] = c;
  95                        continue;
  96                }
  97                if (c == '"') {
  98                        quote = 1-quote;
  99                        continue;
 100                }
 101                value[len++] = c;
 102        }
 103}
 104
 105static inline int iskeychar(int c)
 106{
 107        return isalnum(c) || c == '-';
 108}
 109
 110static int get_value(config_fn_t fn, char *name, unsigned int len)
 111{
 112        int c;
 113        char *value;
 114
 115        /* Get the full name */
 116        for (;;) {
 117                c = get_next_char();
 118                if (c == EOF)
 119                        break;
 120                if (!iskeychar(c))
 121                        break;
 122                name[len++] = tolower(c);
 123                if (len >= MAXNAME)
 124                        return -1;
 125        }
 126        name[len] = 0;
 127        while (c == ' ' || c == '\t')
 128                c = get_next_char();
 129
 130        value = NULL;
 131        if (c != '\n') {
 132                if (c != '=')
 133                        return -1;
 134                value = parse_value();
 135                if (!value)
 136                        return -1;
 137        }
 138        return fn(name, value);
 139}
 140
 141static int get_extended_base_var(char *name, int baselen, int c)
 142{
 143        do {
 144                if (c == '\n')
 145                        return -1;
 146                c = get_next_char();
 147        } while (isspace(c));
 148
 149        /* We require the format to be '[base "extension"]' */
 150        if (c != '"')
 151                return -1;
 152        name[baselen++] = '.';
 153
 154        for (;;) {
 155                int c = get_next_char();
 156                if (c == '\n')
 157                        return -1;
 158                if (c == '"')
 159                        break;
 160                if (c == '\\') {
 161                        c = get_next_char();
 162                        if (c == '\n')
 163                                return -1;
 164                }
 165                name[baselen++] = c;
 166                if (baselen > MAXNAME / 2)
 167                        return -1;
 168        }
 169
 170        /* Final ']' */
 171        if (get_next_char() != ']')
 172                return -1;
 173        return baselen;
 174}
 175
 176static int get_base_var(char *name)
 177{
 178        int baselen = 0;
 179
 180        for (;;) {
 181                int c = get_next_char();
 182                if (c == EOF)
 183                        return -1;
 184                if (c == ']')
 185                        return baselen;
 186                if (isspace(c))
 187                        return get_extended_base_var(name, baselen, c);
 188                if (!iskeychar(c) && c != '.')
 189                        return -1;
 190                if (baselen > MAXNAME / 2)
 191                        return -1;
 192                name[baselen++] = tolower(c);
 193        }
 194}
 195
 196static int git_parse_file(config_fn_t fn)
 197{
 198        int comment = 0;
 199        int baselen = 0;
 200        static char var[MAXNAME];
 201
 202        for (;;) {
 203                int c = get_next_char();
 204                if (c == '\n') {
 205                        /* EOF? */
 206                        if (!config_file)
 207                                return 0;
 208                        comment = 0;
 209                        continue;
 210                }
 211                if (comment || isspace(c))
 212                        continue;
 213                if (c == '#' || c == ';') {
 214                        comment = 1;
 215                        continue;
 216                }
 217                if (c == '[') {
 218                        baselen = get_base_var(var);
 219                        if (baselen <= 0)
 220                                break;
 221                        var[baselen++] = '.';
 222                        var[baselen] = 0;
 223                        continue;
 224                }
 225                if (!isalpha(c))
 226                        break;
 227                var[baselen] = tolower(c);
 228                if (get_value(fn, var, baselen+1) < 0)
 229                        break;
 230        }
 231        die("bad config file line %d in %s", config_linenr, config_file_name);
 232}
 233
 234int git_config_int(const char *name, const char *value)
 235{
 236        if (value && *value) {
 237                char *end;
 238                int val = strtol(value, &end, 0);
 239                if (!*end)
 240                        return val;
 241                if (!strcasecmp(end, "k"))
 242                        return val * 1024;
 243                if (!strcasecmp(end, "m"))
 244                        return val * 1024 * 1024;
 245                if (!strcasecmp(end, "g"))
 246                        return val * 1024 * 1024 * 1024;
 247        }
 248        die("bad config value for '%s' in %s", name, config_file_name);
 249}
 250
 251int git_config_bool(const char *name, const char *value)
 252{
 253        if (!value)
 254                return 1;
 255        if (!*value)
 256                return 0;
 257        if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 258                return 1;
 259        if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 260                return 0;
 261        return git_config_int(name, value) != 0;
 262}
 263
 264int git_default_config(const char *var, const char *value)
 265{
 266        /* This needs a better name */
 267        if (!strcmp(var, "core.filemode")) {
 268                trust_executable_bit = git_config_bool(var, value);
 269                return 0;
 270        }
 271
 272        if (!strcmp(var, "core.bare")) {
 273                is_bare_repository_cfg = git_config_bool(var, value);
 274                return 0;
 275        }
 276
 277        if (!strcmp(var, "core.ignorestat")) {
 278                assume_unchanged = git_config_bool(var, value);
 279                return 0;
 280        }
 281
 282        if (!strcmp(var, "core.prefersymlinkrefs")) {
 283                prefer_symlink_refs = git_config_bool(var, value);
 284                return 0;
 285        }
 286
 287        if (!strcmp(var, "core.logallrefupdates")) {
 288                log_all_ref_updates = git_config_bool(var, value);
 289                return 0;
 290        }
 291
 292        if (!strcmp(var, "core.warnambiguousrefs")) {
 293                warn_ambiguous_refs = git_config_bool(var, value);
 294                return 0;
 295        }
 296
 297        if (!strcmp(var, "core.legacyheaders")) {
 298                use_legacy_headers = git_config_bool(var, value);
 299                return 0;
 300        }
 301
 302        if (!strcmp(var, "core.compression")) {
 303                int level = git_config_int(var, value);
 304                if (level == -1)
 305                        level = Z_DEFAULT_COMPRESSION;
 306                else if (level < 0 || level > Z_BEST_COMPRESSION)
 307                        die("bad zlib compression level %d", level);
 308                zlib_compression_level = level;
 309                return 0;
 310        }
 311
 312        if (!strcmp(var, "core.packedgitwindowsize")) {
 313                int pgsz_x2 = getpagesize() * 2;
 314                packed_git_window_size = git_config_int(var, value);
 315
 316                /* This value must be multiple of (pagesize * 2) */
 317                packed_git_window_size /= pgsz_x2;
 318                if (packed_git_window_size < 1)
 319                        packed_git_window_size = 1;
 320                packed_git_window_size *= pgsz_x2;
 321                return 0;
 322        }
 323
 324        if (!strcmp(var, "core.packedgitlimit")) {
 325                packed_git_limit = git_config_int(var, value);
 326                return 0;
 327        }
 328
 329        if (!strcmp(var, "user.name")) {
 330                strlcpy(git_default_name, value, sizeof(git_default_name));
 331                return 0;
 332        }
 333
 334        if (!strcmp(var, "user.email")) {
 335                strlcpy(git_default_email, value, sizeof(git_default_email));
 336                return 0;
 337        }
 338
 339        if (!strcmp(var, "i18n.commitencoding")) {
 340                git_commit_encoding = strdup(value);
 341                return 0;
 342        }
 343
 344        if (!strcmp(var, "i18n.logoutputencoding")) {
 345                git_log_output_encoding = strdup(value);
 346                return 0;
 347        }
 348
 349
 350        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 351                pager_use_color = git_config_bool(var,value);
 352                return 0;
 353        }
 354
 355        /* Add other config variables here and to Documentation/config.txt. */
 356        return 0;
 357}
 358
 359int git_config_from_file(config_fn_t fn, const char *filename)
 360{
 361        int ret;
 362        FILE *f = fopen(filename, "r");
 363
 364        ret = -1;
 365        if (f) {
 366                config_file = f;
 367                config_file_name = filename;
 368                config_linenr = 1;
 369                ret = git_parse_file(fn);
 370                fclose(f);
 371                config_file_name = NULL;
 372        }
 373        return ret;
 374}
 375
 376int git_config(config_fn_t fn)
 377{
 378        int ret = 0;
 379        char *repo_config = NULL;
 380        const char *home = NULL, *filename;
 381
 382        /* $GIT_CONFIG makes git read _only_ the given config file,
 383         * $GIT_CONFIG_LOCAL will make it process it in addition to the
 384         * global config file, the same way it would the per-repository
 385         * config file otherwise. */
 386        filename = getenv(CONFIG_ENVIRONMENT);
 387        if (!filename) {
 388                home = getenv("HOME");
 389                filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 390                if (!filename)
 391                        filename = repo_config = xstrdup(git_path("config"));
 392        }
 393
 394        if (home) {
 395                char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 396                if (!access(user_config, R_OK))
 397                        ret = git_config_from_file(fn, user_config);
 398                free(user_config);
 399        }
 400
 401        ret += git_config_from_file(fn, filename);
 402        free(repo_config);
 403        return ret;
 404}
 405
 406/*
 407 * Find all the stuff for git_config_set() below.
 408 */
 409
 410#define MAX_MATCHES 512
 411
 412static struct {
 413        int baselen;
 414        char* key;
 415        int do_not_match;
 416        regex_t* value_regex;
 417        int multi_replace;
 418        off_t offset[MAX_MATCHES];
 419        enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 420        int seen;
 421} store;
 422
 423static int matches(const char* key, const char* value)
 424{
 425        return !strcmp(key, store.key) &&
 426                (store.value_regex == NULL ||
 427                 (store.do_not_match ^
 428                  !regexec(store.value_regex, value, 0, NULL, 0)));
 429}
 430
 431static int store_aux(const char* key, const char* value)
 432{
 433        switch (store.state) {
 434        case KEY_SEEN:
 435                if (matches(key, value)) {
 436                        if (store.seen == 1 && store.multi_replace == 0) {
 437                                fprintf(stderr,
 438                                        "Warning: %s has multiple values\n",
 439                                        key);
 440                        } else if (store.seen >= MAX_MATCHES) {
 441                                fprintf(stderr, "Too many matches\n");
 442                                return 1;
 443                        }
 444
 445                        store.offset[store.seen] = ftell(config_file);
 446                        store.seen++;
 447                }
 448                break;
 449        case SECTION_SEEN:
 450                if (strncmp(key, store.key, store.baselen+1)) {
 451                        store.state = SECTION_END_SEEN;
 452                        break;
 453                } else
 454                        /* do not increment matches: this is no match */
 455                        store.offset[store.seen] = ftell(config_file);
 456                /* fallthru */
 457        case SECTION_END_SEEN:
 458        case START:
 459                if (matches(key, value)) {
 460                        store.offset[store.seen] = ftell(config_file);
 461                        store.state = KEY_SEEN;
 462                        store.seen++;
 463                } else {
 464                        if (strrchr(key, '.') - key == store.baselen &&
 465                              !strncmp(key, store.key, store.baselen)) {
 466                                        store.state = SECTION_SEEN;
 467                                        store.offset[store.seen] = ftell(config_file);
 468                        }
 469                }
 470        }
 471        return 0;
 472}
 473
 474static int write_error()
 475{
 476        fprintf(stderr, "Failed to write new configuration file\n");
 477
 478        /* Same error code as "failed to rename". */
 479        return 4;
 480}
 481
 482static int store_write_section(int fd, const char* key)
 483{
 484        const char *dot = strchr(key, '.');
 485        int len1 = store.baselen, len2 = -1;
 486
 487        dot = strchr(key, '.');
 488        if (dot) {
 489                int dotlen = dot - key;
 490                if (dotlen < len1) {
 491                        len2 = len1 - dotlen - 1;
 492                        len1 = dotlen;
 493                }
 494        }
 495
 496        if (write_in_full(fd, "[", 1) != 1 ||
 497            write_in_full(fd, key, len1) != len1)
 498                return 0;
 499        if (len2 >= 0) {
 500                if (write_in_full(fd, " \"", 2) != 2)
 501                        return 0;
 502                while (--len2 >= 0) {
 503                        unsigned char c = *++dot;
 504                        if (c == '"')
 505                                if (write_in_full(fd, "\\", 1) != 1)
 506                                        return 0;
 507                        if (write_in_full(fd, &c, 1) != 1)
 508                                return 0;
 509                }
 510                if (write_in_full(fd, "\"", 1) != 1)
 511                        return 0;
 512        }
 513        if (write_in_full(fd, "]\n", 2) != 2)
 514                return 0;
 515
 516        return 1;
 517}
 518
 519static int store_write_pair(int fd, const char* key, const char* value)
 520{
 521        int i;
 522        int length = strlen(key+store.baselen+1);
 523        int quote = 0;
 524
 525        /* Check to see if the value needs to be quoted. */
 526        if (value[0] == ' ')
 527                quote = 1;
 528        for (i = 0; value[i]; i++)
 529                if (value[i] == ';' || value[i] == '#')
 530                        quote = 1;
 531        if (value[i-1] == ' ')
 532                quote = 1;
 533
 534        if (write_in_full(fd, "\t", 1) != 1 ||
 535            write_in_full(fd, key+store.baselen+1, length) != length ||
 536            write_in_full(fd, " = ", 3) != 3)
 537                return 0;
 538        if (quote && write_in_full(fd, "\"", 1) != 1)
 539                return 0;
 540        for (i = 0; value[i]; i++)
 541                switch (value[i]) {
 542                case '\n':
 543                        if (write_in_full(fd, "\\n", 2) != 2)
 544                                return 0;
 545                        break;
 546                case '\t':
 547                        if (write_in_full(fd, "\\t", 2) != 2)
 548                                return 0;
 549                        break;
 550                case '"':
 551                case '\\':
 552                        if (write_in_full(fd, "\\", 1) != 1)
 553                                return 0;
 554                default:
 555                        if (write_in_full(fd, value+i, 1) != 1)
 556                                return 0;
 557                        break;
 558                }
 559        if (quote && write_in_full(fd, "\"", 1) != 1)
 560                return 0;
 561        if (write_in_full(fd, "\n", 1) != 1)
 562                return 0;
 563        return 1;
 564}
 565
 566static int find_beginning_of_line(const char* contents, int size,
 567        int offset_, int* found_bracket)
 568{
 569        int equal_offset = size, bracket_offset = size;
 570        int offset;
 571
 572        for (offset = offset_-2; offset > 0 
 573                        && contents[offset] != '\n'; offset--)
 574                switch (contents[offset]) {
 575                        case '=': equal_offset = offset; break;
 576                        case ']': bracket_offset = offset; break;
 577                }
 578        if (bracket_offset < equal_offset) {
 579                *found_bracket = 1;
 580                offset = bracket_offset+1;
 581        } else
 582                offset++;
 583
 584        return offset;
 585}
 586
 587int git_config_set(const char* key, const char* value)
 588{
 589        return git_config_set_multivar(key, value, NULL, 0);
 590}
 591
 592/*
 593 * If value==NULL, unset in (remove from) config,
 594 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 595 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 596 *     else all matching key/values (regardless how many) are removed,
 597 *     before the new pair is written.
 598 *
 599 * Returns 0 on success.
 600 *
 601 * This function does this:
 602 *
 603 * - it locks the config file by creating ".git/config.lock"
 604 *
 605 * - it then parses the config using store_aux() as validator to find
 606 *   the position on the key/value pair to replace. If it is to be unset,
 607 *   it must be found exactly once.
 608 *
 609 * - the config file is mmap()ed and the part before the match (if any) is
 610 *   written to the lock file, then the changed part and the rest.
 611 *
 612 * - the config file is removed and the lock file rename()d to it.
 613 *
 614 */
 615int git_config_set_multivar(const char* key, const char* value,
 616        const char* value_regex, int multi_replace)
 617{
 618        int i, dot;
 619        int fd = -1, in_fd;
 620        int ret;
 621        char* config_filename;
 622        char* lock_file;
 623        const char* last_dot = strrchr(key, '.');
 624
 625        config_filename = getenv(CONFIG_ENVIRONMENT);
 626        if (!config_filename) {
 627                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 628                if (!config_filename)
 629                        config_filename  = git_path("config");
 630        }
 631        config_filename = xstrdup(config_filename);
 632        lock_file = xstrdup(mkpath("%s.lock", config_filename));
 633
 634        /*
 635         * Since "key" actually contains the section name and the real
 636         * key name separated by a dot, we have to know where the dot is.
 637         */
 638
 639        if (last_dot == NULL) {
 640                fprintf(stderr, "key does not contain a section: %s\n", key);
 641                ret = 2;
 642                goto out_free;
 643        }
 644        store.baselen = last_dot - key;
 645
 646        store.multi_replace = multi_replace;
 647
 648        /*
 649         * Validate the key and while at it, lower case it for matching.
 650         */
 651        store.key = xmalloc(strlen(key) + 1);
 652        dot = 0;
 653        for (i = 0; key[i]; i++) {
 654                unsigned char c = key[i];
 655                if (c == '.')
 656                        dot = 1;
 657                /* Leave the extended basename untouched.. */
 658                if (!dot || i > store.baselen) {
 659                        if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 660                                fprintf(stderr, "invalid key: %s\n", key);
 661                                free(store.key);
 662                                ret = 1;
 663                                goto out_free;
 664                        }
 665                        c = tolower(c);
 666                } else if (c == '\n') {
 667                        fprintf(stderr, "invalid key (newline): %s\n", key);
 668                        free(store.key);
 669                        ret = 1;
 670                        goto out_free;
 671                }
 672                store.key[i] = c;
 673        }
 674        store.key[i] = 0;
 675
 676        /*
 677         * The lock_file serves a purpose in addition to locking: the new
 678         * contents of .git/config will be written into it.
 679         */
 680        fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 681        if (fd < 0 || adjust_shared_perm(lock_file)) {
 682                fprintf(stderr, "could not lock config file\n");
 683                free(store.key);
 684                ret = -1;
 685                goto out_free;
 686        }
 687
 688        /*
 689         * If .git/config does not exist yet, write a minimal version.
 690         */
 691        in_fd = open(config_filename, O_RDONLY);
 692        if ( in_fd < 0 ) {
 693                free(store.key);
 694
 695                if ( ENOENT != errno ) {
 696                        error("opening %s: %s", config_filename,
 697                              strerror(errno));
 698                        ret = 3; /* same as "invalid config file" */
 699                        goto out_free;
 700                }
 701                /* if nothing to unset, error out */
 702                if (value == NULL) {
 703                        ret = 5;
 704                        goto out_free;
 705                }
 706
 707                store.key = (char*)key;
 708                if (!store_write_section(fd, key) ||
 709                    !store_write_pair(fd, key, value))
 710                        goto write_err_out;
 711        } else {
 712                struct stat st;
 713                char* contents;
 714                int i, copy_begin, copy_end, new_line = 0;
 715
 716                if (value_regex == NULL)
 717                        store.value_regex = NULL;
 718                else {
 719                        if (value_regex[0] == '!') {
 720                                store.do_not_match = 1;
 721                                value_regex++;
 722                        } else
 723                                store.do_not_match = 0;
 724
 725                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 726                        if (regcomp(store.value_regex, value_regex,
 727                                        REG_EXTENDED)) {
 728                                fprintf(stderr, "Invalid pattern: %s\n",
 729                                        value_regex);
 730                                free(store.value_regex);
 731                                ret = 6;
 732                                goto out_free;
 733                        }
 734                }
 735
 736                store.offset[0] = 0;
 737                store.state = START;
 738                store.seen = 0;
 739
 740                /*
 741                 * After this, store.offset will contain the *end* offset
 742                 * of the last match, or remain at 0 if no match was found.
 743                 * As a side effect, we make sure to transform only a valid
 744                 * existing config file.
 745                 */
 746                if (git_config_from_file(store_aux, config_filename)) {
 747                        fprintf(stderr, "invalid config file\n");
 748                        free(store.key);
 749                        if (store.value_regex != NULL) {
 750                                regfree(store.value_regex);
 751                                free(store.value_regex);
 752                        }
 753                        ret = 3;
 754                        goto out_free;
 755                }
 756
 757                free(store.key);
 758                if (store.value_regex != NULL) {
 759                        regfree(store.value_regex);
 760                        free(store.value_regex);
 761                }
 762
 763                /* if nothing to unset, or too many matches, error out */
 764                if ((store.seen == 0 && value == NULL) ||
 765                                (store.seen > 1 && multi_replace == 0)) {
 766                        ret = 5;
 767                        goto out_free;
 768                }
 769
 770                fstat(in_fd, &st);
 771                contents = xmmap(NULL, st.st_size, PROT_READ,
 772                        MAP_PRIVATE, in_fd, 0);
 773                close(in_fd);
 774
 775                if (store.seen == 0)
 776                        store.seen = 1;
 777
 778                for (i = 0, copy_begin = 0; i < store.seen; i++) {
 779                        if (store.offset[i] == 0) {
 780                                store.offset[i] = copy_end = st.st_size;
 781                        } else if (store.state != KEY_SEEN) {
 782                                copy_end = store.offset[i];
 783                        } else
 784                                copy_end = find_beginning_of_line(
 785                                        contents, st.st_size,
 786                                        store.offset[i]-2, &new_line);
 787
 788                        /* write the first part of the config */
 789                        if (copy_end > copy_begin) {
 790                                if (write_in_full(fd, contents + copy_begin,
 791                                                  copy_end - copy_begin) <
 792                                    copy_end - copy_begin)
 793                                        goto write_err_out;
 794                                if (new_line &&
 795                                    write_in_full(fd, "\n", 1) != 1)
 796                                        goto write_err_out;
 797                        }
 798                        copy_begin = store.offset[i];
 799                }
 800
 801                /* write the pair (value == NULL means unset) */
 802                if (value != NULL) {
 803                        if (store.state == START) {
 804                                if (!store_write_section(fd, key))
 805                                        goto write_err_out;
 806                        }
 807                        if (!store_write_pair(fd, key, value))
 808                                goto write_err_out;
 809                }
 810
 811                /* write the rest of the config */
 812                if (copy_begin < st.st_size)
 813                        if (write_in_full(fd, contents + copy_begin,
 814                                          st.st_size - copy_begin) <
 815                            st.st_size - copy_begin)
 816                                goto write_err_out;
 817
 818                munmap(contents, st.st_size);
 819                unlink(config_filename);
 820        }
 821
 822        if (rename(lock_file, config_filename) < 0) {
 823                fprintf(stderr, "Could not rename the lock file?\n");
 824                ret = 4;
 825                goto out_free;
 826        }
 827
 828        ret = 0;
 829
 830out_free:
 831        if (0 <= fd)
 832                close(fd);
 833        free(config_filename);
 834        if (lock_file) {
 835                unlink(lock_file);
 836                free(lock_file);
 837        }
 838        return ret;
 839
 840write_err_out:
 841        ret = write_error();
 842        goto out_free;
 843
 844}
 845
 846int git_config_rename_section(const char *old_name, const char *new_name)
 847{
 848        int ret = 0;
 849        char *config_filename;
 850        struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 851        int out_fd;
 852        char buf[1024];
 853
 854        config_filename = getenv(CONFIG_ENVIRONMENT);
 855        if (!config_filename) {
 856                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 857                if (!config_filename)
 858                        config_filename  = git_path("config");
 859        }
 860        config_filename = xstrdup(config_filename);
 861        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 862        if (out_fd < 0) {
 863                ret = error("Could not lock config file!");
 864                goto out;
 865        }
 866
 867        if (!(config_file = fopen(config_filename, "rb"))) {
 868                ret = error("Could not open config file!");
 869                goto out;
 870        }
 871
 872        while (fgets(buf, sizeof(buf), config_file)) {
 873                int i;
 874                int length;
 875                for (i = 0; buf[i] && isspace(buf[i]); i++)
 876                        ; /* do nothing */
 877                if (buf[i] == '[') {
 878                        /* it's a section */
 879                        int j = 0, dot = 0;
 880                        for (i++; buf[i] && buf[i] != ']'; i++) {
 881                                if (!dot && isspace(buf[i])) {
 882                                        dot = 1;
 883                                        if (old_name[j++] != '.')
 884                                                break;
 885                                        for (i++; isspace(buf[i]); i++)
 886                                                ; /* do nothing */
 887                                        if (buf[i] != '"')
 888                                                break;
 889                                        continue;
 890                                }
 891                                if (buf[i] == '\\' && dot)
 892                                        i++;
 893                                else if (buf[i] == '"' && dot) {
 894                                        for (i++; isspace(buf[i]); i++)
 895                                                ; /* do_nothing */
 896                                        break;
 897                                }
 898                                if (buf[i] != old_name[j++])
 899                                        break;
 900                        }
 901                        if (buf[i] == ']' && old_name[j] == 0) {
 902                                /* old_name matches */
 903                                ret++;
 904                                store.baselen = strlen(new_name);
 905                                if (!store_write_section(out_fd, new_name)) {
 906                                        ret = write_error();
 907                                        goto out;
 908                                }
 909                                continue;
 910                        }
 911                }
 912                length = strlen(buf);
 913                if (write_in_full(out_fd, buf, length) != length) {
 914                        ret = write_error();
 915                        goto out;
 916                }
 917        }
 918        fclose(config_file);
 919        if (close(out_fd) || commit_lock_file(lock) < 0)
 920                        ret = error("Cannot commit config file!");
 921 out:
 922        free(config_filename);
 923        return ret;
 924}
 925