config.con commit Merge branch 'maint' (7f09ac4)
   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.symlinks")) {
 273                has_symlinks = git_config_bool(var, value);
 274                return 0;
 275        }
 276
 277        if (!strcmp(var, "core.bare")) {
 278                is_bare_repository_cfg = git_config_bool(var, value);
 279                return 0;
 280        }
 281
 282        if (!strcmp(var, "core.ignorestat")) {
 283                assume_unchanged = git_config_bool(var, value);
 284                return 0;
 285        }
 286
 287        if (!strcmp(var, "core.prefersymlinkrefs")) {
 288                prefer_symlink_refs = git_config_bool(var, value);
 289                return 0;
 290        }
 291
 292        if (!strcmp(var, "core.logallrefupdates")) {
 293                log_all_ref_updates = git_config_bool(var, value);
 294                return 0;
 295        }
 296
 297        if (!strcmp(var, "core.warnambiguousrefs")) {
 298                warn_ambiguous_refs = git_config_bool(var, value);
 299                return 0;
 300        }
 301
 302        if (!strcmp(var, "core.legacyheaders")) {
 303                use_legacy_headers = git_config_bool(var, value);
 304                return 0;
 305        }
 306
 307        if (!strcmp(var, "core.compression")) {
 308                int level = git_config_int(var, value);
 309                if (level == -1)
 310                        level = Z_DEFAULT_COMPRESSION;
 311                else if (level < 0 || level > Z_BEST_COMPRESSION)
 312                        die("bad zlib compression level %d", level);
 313                zlib_compression_level = level;
 314                return 0;
 315        }
 316
 317        if (!strcmp(var, "core.packedgitwindowsize")) {
 318                int pgsz_x2 = getpagesize() * 2;
 319                packed_git_window_size = git_config_int(var, value);
 320
 321                /* This value must be multiple of (pagesize * 2) */
 322                packed_git_window_size /= pgsz_x2;
 323                if (packed_git_window_size < 1)
 324                        packed_git_window_size = 1;
 325                packed_git_window_size *= pgsz_x2;
 326                return 0;
 327        }
 328
 329        if (!strcmp(var, "core.packedgitlimit")) {
 330                packed_git_limit = git_config_int(var, value);
 331                return 0;
 332        }
 333
 334        if (!strcmp(var, "core.autocrlf")) {
 335                if (value && !strcasecmp(value, "input")) {
 336                        auto_crlf = -1;
 337                        return 0;
 338                }
 339                auto_crlf = git_config_bool(var, value);
 340                return 0;
 341        }
 342
 343        if (!strcmp(var, "user.name")) {
 344                strlcpy(git_default_name, value, sizeof(git_default_name));
 345                return 0;
 346        }
 347
 348        if (!strcmp(var, "user.email")) {
 349                strlcpy(git_default_email, value, sizeof(git_default_email));
 350                return 0;
 351        }
 352
 353        if (!strcmp(var, "i18n.commitencoding")) {
 354                git_commit_encoding = strdup(value);
 355                return 0;
 356        }
 357
 358        if (!strcmp(var, "i18n.logoutputencoding")) {
 359                git_log_output_encoding = strdup(value);
 360                return 0;
 361        }
 362
 363
 364        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 365                pager_use_color = git_config_bool(var,value);
 366                return 0;
 367        }
 368
 369        /* Add other config variables here and to Documentation/config.txt. */
 370        return 0;
 371}
 372
 373int git_config_from_file(config_fn_t fn, const char *filename)
 374{
 375        int ret;
 376        FILE *f = fopen(filename, "r");
 377
 378        ret = -1;
 379        if (f) {
 380                config_file = f;
 381                config_file_name = filename;
 382                config_linenr = 1;
 383                ret = git_parse_file(fn);
 384                fclose(f);
 385                config_file_name = NULL;
 386        }
 387        return ret;
 388}
 389
 390int git_config(config_fn_t fn)
 391{
 392        int ret = 0;
 393        char *repo_config = NULL;
 394        const char *home = NULL, *filename;
 395
 396        /* $GIT_CONFIG makes git read _only_ the given config file,
 397         * $GIT_CONFIG_LOCAL will make it process it in addition to the
 398         * global config file, the same way it would the per-repository
 399         * config file otherwise. */
 400        filename = getenv(CONFIG_ENVIRONMENT);
 401        if (!filename) {
 402                if (!access(ETC_GITCONFIG, R_OK))
 403                        ret += git_config_from_file(fn, ETC_GITCONFIG);
 404                home = getenv("HOME");
 405                filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 406                if (!filename)
 407                        filename = repo_config = xstrdup(git_path("config"));
 408        }
 409
 410        if (home) {
 411                char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 412                if (!access(user_config, R_OK))
 413                        ret = git_config_from_file(fn, user_config);
 414                free(user_config);
 415        }
 416
 417        ret += git_config_from_file(fn, filename);
 418        free(repo_config);
 419        return ret;
 420}
 421
 422/*
 423 * Find all the stuff for git_config_set() below.
 424 */
 425
 426#define MAX_MATCHES 512
 427
 428static struct {
 429        int baselen;
 430        char* key;
 431        int do_not_match;
 432        regex_t* value_regex;
 433        int multi_replace;
 434        size_t offset[MAX_MATCHES];
 435        enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 436        int seen;
 437} store;
 438
 439static int matches(const char* key, const char* value)
 440{
 441        return !strcmp(key, store.key) &&
 442                (store.value_regex == NULL ||
 443                 (store.do_not_match ^
 444                  !regexec(store.value_regex, value, 0, NULL, 0)));
 445}
 446
 447static int store_aux(const char* key, const char* value)
 448{
 449        switch (store.state) {
 450        case KEY_SEEN:
 451                if (matches(key, value)) {
 452                        if (store.seen == 1 && store.multi_replace == 0) {
 453                                fprintf(stderr,
 454                                        "Warning: %s has multiple values\n",
 455                                        key);
 456                        } else if (store.seen >= MAX_MATCHES) {
 457                                fprintf(stderr, "Too many matches\n");
 458                                return 1;
 459                        }
 460
 461                        store.offset[store.seen] = ftell(config_file);
 462                        store.seen++;
 463                }
 464                break;
 465        case SECTION_SEEN:
 466                if (strncmp(key, store.key, store.baselen+1)) {
 467                        store.state = SECTION_END_SEEN;
 468                        break;
 469                } else
 470                        /* do not increment matches: this is no match */
 471                        store.offset[store.seen] = ftell(config_file);
 472                /* fallthru */
 473        case SECTION_END_SEEN:
 474        case START:
 475                if (matches(key, value)) {
 476                        store.offset[store.seen] = ftell(config_file);
 477                        store.state = KEY_SEEN;
 478                        store.seen++;
 479                } else {
 480                        if (strrchr(key, '.') - key == store.baselen &&
 481                              !strncmp(key, store.key, store.baselen)) {
 482                                        store.state = SECTION_SEEN;
 483                                        store.offset[store.seen] = ftell(config_file);
 484                        }
 485                }
 486        }
 487        return 0;
 488}
 489
 490static int write_error()
 491{
 492        fprintf(stderr, "Failed to write new configuration file\n");
 493
 494        /* Same error code as "failed to rename". */
 495        return 4;
 496}
 497
 498static int store_write_section(int fd, const char* key)
 499{
 500        const char *dot = strchr(key, '.');
 501        int len1 = store.baselen, len2 = -1;
 502
 503        dot = strchr(key, '.');
 504        if (dot) {
 505                int dotlen = dot - key;
 506                if (dotlen < len1) {
 507                        len2 = len1 - dotlen - 1;
 508                        len1 = dotlen;
 509                }
 510        }
 511
 512        if (write_in_full(fd, "[", 1) != 1 ||
 513            write_in_full(fd, key, len1) != len1)
 514                return 0;
 515        if (len2 >= 0) {
 516                if (write_in_full(fd, " \"", 2) != 2)
 517                        return 0;
 518                while (--len2 >= 0) {
 519                        unsigned char c = *++dot;
 520                        if (c == '"')
 521                                if (write_in_full(fd, "\\", 1) != 1)
 522                                        return 0;
 523                        if (write_in_full(fd, &c, 1) != 1)
 524                                return 0;
 525                }
 526                if (write_in_full(fd, "\"", 1) != 1)
 527                        return 0;
 528        }
 529        if (write_in_full(fd, "]\n", 2) != 2)
 530                return 0;
 531
 532        return 1;
 533}
 534
 535static int store_write_pair(int fd, const char* key, const char* value)
 536{
 537        int i;
 538        int length = strlen(key+store.baselen+1);
 539        int quote = 0;
 540
 541        /* Check to see if the value needs to be quoted. */
 542        if (value[0] == ' ')
 543                quote = 1;
 544        for (i = 0; value[i]; i++)
 545                if (value[i] == ';' || value[i] == '#')
 546                        quote = 1;
 547        if (value[i-1] == ' ')
 548                quote = 1;
 549
 550        if (write_in_full(fd, "\t", 1) != 1 ||
 551            write_in_full(fd, key+store.baselen+1, length) != length ||
 552            write_in_full(fd, " = ", 3) != 3)
 553                return 0;
 554        if (quote && write_in_full(fd, "\"", 1) != 1)
 555                return 0;
 556        for (i = 0; value[i]; i++)
 557                switch (value[i]) {
 558                case '\n':
 559                        if (write_in_full(fd, "\\n", 2) != 2)
 560                                return 0;
 561                        break;
 562                case '\t':
 563                        if (write_in_full(fd, "\\t", 2) != 2)
 564                                return 0;
 565                        break;
 566                case '"':
 567                case '\\':
 568                        if (write_in_full(fd, "\\", 1) != 1)
 569                                return 0;
 570                default:
 571                        if (write_in_full(fd, value+i, 1) != 1)
 572                                return 0;
 573                        break;
 574                }
 575        if (quote && write_in_full(fd, "\"", 1) != 1)
 576                return 0;
 577        if (write_in_full(fd, "\n", 1) != 1)
 578                return 0;
 579        return 1;
 580}
 581
 582static ssize_t find_beginning_of_line(const char* contents, size_t size,
 583        size_t offset_, int* found_bracket)
 584{
 585        size_t equal_offset = size, bracket_offset = size;
 586        ssize_t offset;
 587
 588        for (offset = offset_-2; offset > 0 
 589                        && contents[offset] != '\n'; offset--)
 590                switch (contents[offset]) {
 591                        case '=': equal_offset = offset; break;
 592                        case ']': bracket_offset = offset; break;
 593                }
 594        if (bracket_offset < equal_offset) {
 595                *found_bracket = 1;
 596                offset = bracket_offset+1;
 597        } else
 598                offset++;
 599
 600        return offset;
 601}
 602
 603int git_config_set(const char* key, const char* value)
 604{
 605        return git_config_set_multivar(key, value, NULL, 0);
 606}
 607
 608/*
 609 * If value==NULL, unset in (remove from) config,
 610 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 611 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 612 *     else all matching key/values (regardless how many) are removed,
 613 *     before the new pair is written.
 614 *
 615 * Returns 0 on success.
 616 *
 617 * This function does this:
 618 *
 619 * - it locks the config file by creating ".git/config.lock"
 620 *
 621 * - it then parses the config using store_aux() as validator to find
 622 *   the position on the key/value pair to replace. If it is to be unset,
 623 *   it must be found exactly once.
 624 *
 625 * - the config file is mmap()ed and the part before the match (if any) is
 626 *   written to the lock file, then the changed part and the rest.
 627 *
 628 * - the config file is removed and the lock file rename()d to it.
 629 *
 630 */
 631int git_config_set_multivar(const char* key, const char* value,
 632        const char* value_regex, int multi_replace)
 633{
 634        int i, dot;
 635        int fd = -1, in_fd;
 636        int ret;
 637        char* config_filename;
 638        char* lock_file;
 639        const char* last_dot = strrchr(key, '.');
 640
 641        config_filename = getenv(CONFIG_ENVIRONMENT);
 642        if (!config_filename) {
 643                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 644                if (!config_filename)
 645                        config_filename  = git_path("config");
 646        }
 647        config_filename = xstrdup(config_filename);
 648        lock_file = xstrdup(mkpath("%s.lock", config_filename));
 649
 650        /*
 651         * Since "key" actually contains the section name and the real
 652         * key name separated by a dot, we have to know where the dot is.
 653         */
 654
 655        if (last_dot == NULL) {
 656                fprintf(stderr, "key does not contain a section: %s\n", key);
 657                ret = 2;
 658                goto out_free;
 659        }
 660        store.baselen = last_dot - key;
 661
 662        store.multi_replace = multi_replace;
 663
 664        /*
 665         * Validate the key and while at it, lower case it for matching.
 666         */
 667        store.key = xmalloc(strlen(key) + 1);
 668        dot = 0;
 669        for (i = 0; key[i]; i++) {
 670                unsigned char c = key[i];
 671                if (c == '.')
 672                        dot = 1;
 673                /* Leave the extended basename untouched.. */
 674                if (!dot || i > store.baselen) {
 675                        if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 676                                fprintf(stderr, "invalid key: %s\n", key);
 677                                free(store.key);
 678                                ret = 1;
 679                                goto out_free;
 680                        }
 681                        c = tolower(c);
 682                } else if (c == '\n') {
 683                        fprintf(stderr, "invalid key (newline): %s\n", key);
 684                        free(store.key);
 685                        ret = 1;
 686                        goto out_free;
 687                }
 688                store.key[i] = c;
 689        }
 690        store.key[i] = 0;
 691
 692        /*
 693         * The lock_file serves a purpose in addition to locking: the new
 694         * contents of .git/config will be written into it.
 695         */
 696        fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 697        if (fd < 0 || adjust_shared_perm(lock_file)) {
 698                fprintf(stderr, "could not lock config file\n");
 699                free(store.key);
 700                ret = -1;
 701                goto out_free;
 702        }
 703
 704        /*
 705         * If .git/config does not exist yet, write a minimal version.
 706         */
 707        in_fd = open(config_filename, O_RDONLY);
 708        if ( in_fd < 0 ) {
 709                free(store.key);
 710
 711                if ( ENOENT != errno ) {
 712                        error("opening %s: %s", config_filename,
 713                              strerror(errno));
 714                        ret = 3; /* same as "invalid config file" */
 715                        goto out_free;
 716                }
 717                /* if nothing to unset, error out */
 718                if (value == NULL) {
 719                        ret = 5;
 720                        goto out_free;
 721                }
 722
 723                store.key = (char*)key;
 724                if (!store_write_section(fd, key) ||
 725                    !store_write_pair(fd, key, value))
 726                        goto write_err_out;
 727        } else {
 728                struct stat st;
 729                char* contents;
 730                size_t contents_sz, copy_begin, copy_end;
 731                int i, new_line = 0;
 732
 733                if (value_regex == NULL)
 734                        store.value_regex = NULL;
 735                else {
 736                        if (value_regex[0] == '!') {
 737                                store.do_not_match = 1;
 738                                value_regex++;
 739                        } else
 740                                store.do_not_match = 0;
 741
 742                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 743                        if (regcomp(store.value_regex, value_regex,
 744                                        REG_EXTENDED)) {
 745                                fprintf(stderr, "Invalid pattern: %s\n",
 746                                        value_regex);
 747                                free(store.value_regex);
 748                                ret = 6;
 749                                goto out_free;
 750                        }
 751                }
 752
 753                store.offset[0] = 0;
 754                store.state = START;
 755                store.seen = 0;
 756
 757                /*
 758                 * After this, store.offset will contain the *end* offset
 759                 * of the last match, or remain at 0 if no match was found.
 760                 * As a side effect, we make sure to transform only a valid
 761                 * existing config file.
 762                 */
 763                if (git_config_from_file(store_aux, config_filename)) {
 764                        fprintf(stderr, "invalid config file\n");
 765                        free(store.key);
 766                        if (store.value_regex != NULL) {
 767                                regfree(store.value_regex);
 768                                free(store.value_regex);
 769                        }
 770                        ret = 3;
 771                        goto out_free;
 772                }
 773
 774                free(store.key);
 775                if (store.value_regex != NULL) {
 776                        regfree(store.value_regex);
 777                        free(store.value_regex);
 778                }
 779
 780                /* if nothing to unset, or too many matches, error out */
 781                if ((store.seen == 0 && value == NULL) ||
 782                                (store.seen > 1 && multi_replace == 0)) {
 783                        ret = 5;
 784                        goto out_free;
 785                }
 786
 787                fstat(in_fd, &st);
 788                contents_sz = xsize_t(st.st_size);
 789                contents = xmmap(NULL, contents_sz, PROT_READ,
 790                        MAP_PRIVATE, in_fd, 0);
 791                close(in_fd);
 792
 793                if (store.seen == 0)
 794                        store.seen = 1;
 795
 796                for (i = 0, copy_begin = 0; i < store.seen; i++) {
 797                        if (store.offset[i] == 0) {
 798                                store.offset[i] = copy_end = contents_sz;
 799                        } else if (store.state != KEY_SEEN) {
 800                                copy_end = store.offset[i];
 801                        } else
 802                                copy_end = find_beginning_of_line(
 803                                        contents, contents_sz,
 804                                        store.offset[i]-2, &new_line);
 805
 806                        /* write the first part of the config */
 807                        if (copy_end > copy_begin) {
 808                                if (write_in_full(fd, contents + copy_begin,
 809                                                  copy_end - copy_begin) <
 810                                    copy_end - copy_begin)
 811                                        goto write_err_out;
 812                                if (new_line &&
 813                                    write_in_full(fd, "\n", 1) != 1)
 814                                        goto write_err_out;
 815                        }
 816                        copy_begin = store.offset[i];
 817                }
 818
 819                /* write the pair (value == NULL means unset) */
 820                if (value != NULL) {
 821                        if (store.state == START) {
 822                                if (!store_write_section(fd, key))
 823                                        goto write_err_out;
 824                        }
 825                        if (!store_write_pair(fd, key, value))
 826                                goto write_err_out;
 827                }
 828
 829                /* write the rest of the config */
 830                if (copy_begin < contents_sz)
 831                        if (write_in_full(fd, contents + copy_begin,
 832                                          contents_sz - copy_begin) <
 833                            contents_sz - copy_begin)
 834                                goto write_err_out;
 835
 836                munmap(contents, contents_sz);
 837                unlink(config_filename);
 838        }
 839
 840        if (rename(lock_file, config_filename) < 0) {
 841                fprintf(stderr, "Could not rename the lock file?\n");
 842                ret = 4;
 843                goto out_free;
 844        }
 845
 846        ret = 0;
 847
 848out_free:
 849        if (0 <= fd)
 850                close(fd);
 851        free(config_filename);
 852        if (lock_file) {
 853                unlink(lock_file);
 854                free(lock_file);
 855        }
 856        return ret;
 857
 858write_err_out:
 859        ret = write_error();
 860        goto out_free;
 861
 862}
 863
 864static int section_name_match (const char *buf, const char *name)
 865{
 866        int i = 0, j = 0, dot = 0;
 867        for (; buf[i] && buf[i] != ']'; i++) {
 868                if (!dot && isspace(buf[i])) {
 869                        dot = 1;
 870                        if (name[j++] != '.')
 871                                break;
 872                        for (i++; isspace(buf[i]); i++)
 873                                ; /* do nothing */
 874                        if (buf[i] != '"')
 875                                break;
 876                        continue;
 877                }
 878                if (buf[i] == '\\' && dot)
 879                        i++;
 880                else if (buf[i] == '"' && dot) {
 881                        for (i++; isspace(buf[i]); i++)
 882                                ; /* do_nothing */
 883                        break;
 884                }
 885                if (buf[i] != name[j++])
 886                        break;
 887        }
 888        return (buf[i] == ']' && name[j] == 0);
 889}
 890
 891/* if new_name == NULL, the section is removed instead */
 892int git_config_rename_section(const char *old_name, const char *new_name)
 893{
 894        int ret = 0, remove = 0;
 895        char *config_filename;
 896        struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 897        int out_fd;
 898        char buf[1024];
 899
 900        config_filename = getenv(CONFIG_ENVIRONMENT);
 901        if (!config_filename) {
 902                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 903                if (!config_filename)
 904                        config_filename  = git_path("config");
 905        }
 906        config_filename = xstrdup(config_filename);
 907        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 908        if (out_fd < 0) {
 909                ret = error("Could not lock config file!");
 910                goto out;
 911        }
 912
 913        if (!(config_file = fopen(config_filename, "rb"))) {
 914                ret = error("Could not open config file!");
 915                goto out;
 916        }
 917
 918        while (fgets(buf, sizeof(buf), config_file)) {
 919                int i;
 920                int length;
 921                for (i = 0; buf[i] && isspace(buf[i]); i++)
 922                        ; /* do nothing */
 923                if (buf[i] == '[') {
 924                        /* it's a section */
 925                        if (section_name_match (&buf[i+1], old_name)) {
 926                                ret++;
 927                                if (new_name == NULL) {
 928                                        remove = 1;
 929                                        continue;
 930                                }
 931                                store.baselen = strlen(new_name);
 932                                if (!store_write_section(out_fd, new_name)) {
 933                                        ret = write_error();
 934                                        goto out;
 935                                }
 936                                continue;
 937                        }
 938                        remove = 0;
 939                }
 940                if (remove)
 941                        continue;
 942                length = strlen(buf);
 943                if (write_in_full(out_fd, buf, length) != length) {
 944                        ret = write_error();
 945                        goto out;
 946                }
 947        }
 948        fclose(config_file);
 949        if (close(out_fd) || commit_lock_file(lock) < 0)
 950                        ret = error("Cannot commit config file!");
 951 out:
 952        free(config_filename);
 953        return ret;
 954}
 955