Andrew's git / gitweb.git / config.c
?
config.con commit fix doc typos (a5d86f7)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 * Copyright (C) Johannes Schindelin, 2005
   6 *
   7 */
   8#include "cache.h"
   9#include "exec_cmd.h"
  10
  11#define MAXNAME (256)
  12
  13static FILE *config_file;
  14static const char *config_file_name;
  15static int config_linenr;
  16static int config_file_eof;
  17static int zlib_compression_seen;
  18
  19static int get_next_char(void)
  20{
  21        int c;
  22        FILE *f;
  23
  24        c = '\n';
  25        if ((f = config_file) != NULL) {
  26                c = fgetc(f);
  27                if (c == '\r') {
  28                        /* DOS like systems */
  29                        c = fgetc(f);
  30                        if (c != '\n') {
  31                                ungetc(c, f);
  32                                c = '\r';
  33                        }
  34                }
  35                if (c == '\n')
  36                        config_linenr++;
  37                if (c == EOF) {
  38                        config_file_eof = 1;
  39                        c = '\n';
  40                }
  41        }
  42        return c;
  43}
  44
  45static char *parse_value(void)
  46{
  47        static char value[1024];
  48        int quote = 0, comment = 0, len = 0, space = 0;
  49
  50        for (;;) {
  51                int c = get_next_char();
  52                if (len >= sizeof(value))
  53                        return NULL;
  54                if (c == '\n') {
  55                        if (quote)
  56                                return NULL;
  57                        value[len] = 0;
  58                        return value;
  59                }
  60                if (comment)
  61                        continue;
  62                if (isspace(c) && !quote) {
  63                        space = 1;
  64                        continue;
  65                }
  66                if (!quote) {
  67                        if (c == ';' || c == '#') {
  68                                comment = 1;
  69                                continue;
  70                        }
  71                }
  72                if (space) {
  73                        if (len)
  74                                value[len++] = ' ';
  75                        space = 0;
  76                }
  77                if (c == '\\') {
  78                        c = get_next_char();
  79                        switch (c) {
  80                        case '\n':
  81                                continue;
  82                        case 't':
  83                                c = '\t';
  84                                break;
  85                        case 'b':
  86                                c = '\b';
  87                                break;
  88                        case 'n':
  89                                c = '\n';
  90                                break;
  91                        /* Some characters escape as themselves */
  92                        case '\\': case '"':
  93                                break;
  94                        /* Reject unknown escape sequences */
  95                        default:
  96                                return NULL;
  97                        }
  98                        value[len++] = c;
  99                        continue;
 100                }
 101                if (c == '"') {
 102                        quote = 1-quote;
 103                        continue;
 104                }
 105                value[len++] = c;
 106        }
 107}
 108
 109static inline int iskeychar(int c)
 110{
 111        return isalnum(c) || c == '-';
 112}
 113
 114static int get_value(config_fn_t fn, char *name, unsigned int len)
 115{
 116        int c;
 117        char *value;
 118
 119        /* Get the full name */
 120        for (;;) {
 121                c = get_next_char();
 122                if (config_file_eof)
 123                        break;
 124                if (!iskeychar(c))
 125                        break;
 126                name[len++] = tolower(c);
 127                if (len >= MAXNAME)
 128                        return -1;
 129        }
 130        name[len] = 0;
 131        while (c == ' ' || c == '\t')
 132                c = get_next_char();
 133
 134        value = NULL;
 135        if (c != '\n') {
 136                if (c != '=')
 137                        return -1;
 138                value = parse_value();
 139                if (!value)
 140                        return -1;
 141        }
 142        return fn(name, value);
 143}
 144
 145static int get_extended_base_var(char *name, int baselen, int c)
 146{
 147        do {
 148                if (c == '\n')
 149                        return -1;
 150                c = get_next_char();
 151        } while (isspace(c));
 152
 153        /* We require the format to be '[base "extension"]' */
 154        if (c != '"')
 155                return -1;
 156        name[baselen++] = '.';
 157
 158        for (;;) {
 159                int c = get_next_char();
 160                if (c == '\n')
 161                        return -1;
 162                if (c == '"')
 163                        break;
 164                if (c == '\\') {
 165                        c = get_next_char();
 166                        if (c == '\n')
 167                                return -1;
 168                }
 169                name[baselen++] = c;
 170                if (baselen > MAXNAME / 2)
 171                        return -1;
 172        }
 173
 174        /* Final ']' */
 175        if (get_next_char() != ']')
 176                return -1;
 177        return baselen;
 178}
 179
 180static int get_base_var(char *name)
 181{
 182        int baselen = 0;
 183
 184        for (;;) {
 185                int c = get_next_char();
 186                if (config_file_eof)
 187                        return -1;
 188                if (c == ']')
 189                        return baselen;
 190                if (isspace(c))
 191                        return get_extended_base_var(name, baselen, c);
 192                if (!iskeychar(c) && c != '.')
 193                        return -1;
 194                if (baselen > MAXNAME / 2)
 195                        return -1;
 196                name[baselen++] = tolower(c);
 197        }
 198}
 199
 200static int git_parse_file(config_fn_t fn)
 201{
 202        int comment = 0;
 203        int baselen = 0;
 204        static char var[MAXNAME];
 205
 206        for (;;) {
 207                int c = get_next_char();
 208                if (c == '\n') {
 209                        if (config_file_eof)
 210                                return 0;
 211                        comment = 0;
 212                        continue;
 213                }
 214                if (comment || isspace(c))
 215                        continue;
 216                if (c == '#' || c == ';') {
 217                        comment = 1;
 218                        continue;
 219                }
 220                if (c == '[') {
 221                        baselen = get_base_var(var);
 222                        if (baselen <= 0)
 223                                break;
 224                        var[baselen++] = '.';
 225                        var[baselen] = 0;
 226                        continue;
 227                }
 228                if (!isalpha(c))
 229                        break;
 230                var[baselen] = tolower(c);
 231                if (get_value(fn, var, baselen+1) < 0)
 232                        break;
 233        }
 234        die("bad config file line %d in %s", config_linenr, config_file_name);
 235}
 236
 237static int parse_unit_factor(const char *end, unsigned long *val)
 238{
 239        if (!*end)
 240                return 1;
 241        else if (!strcasecmp(end, "k")) {
 242                *val *= 1024;
 243                return 1;
 244        }
 245        else if (!strcasecmp(end, "m")) {
 246                *val *= 1024 * 1024;
 247                return 1;
 248        }
 249        else if (!strcasecmp(end, "g")) {
 250                *val *= 1024 * 1024 * 1024;
 251                return 1;
 252        }
 253        return 0;
 254}
 255
 256int git_parse_long(const char *value, long *ret)
 257{
 258        if (value && *value) {
 259                char *end;
 260                long val = strtol(value, &end, 0);
 261                unsigned long factor = 1;
 262                if (!parse_unit_factor(end, &factor))
 263                        return 0;
 264                *ret = val * factor;
 265                return 1;
 266        }
 267        return 0;
 268}
 269
 270int git_parse_ulong(const char *value, unsigned long *ret)
 271{
 272        if (value && *value) {
 273                char *end;
 274                unsigned long val = strtoul(value, &end, 0);
 275                if (!parse_unit_factor(end, &val))
 276                        return 0;
 277                *ret = val;
 278                return 1;
 279        }
 280        return 0;
 281}
 282
 283int git_config_int(const char *name, const char *value)
 284{
 285        long ret;
 286        if (!git_parse_long(value, &ret))
 287                die("bad config value for '%s' in %s", name, config_file_name);
 288        return ret;
 289}
 290
 291unsigned long git_config_ulong(const char *name, const char *value)
 292{
 293        unsigned long ret;
 294        if (!git_parse_ulong(value, &ret))
 295                die("bad config value for '%s' in %s", name, config_file_name);
 296        return ret;
 297}
 298
 299int git_config_bool(const char *name, const char *value)
 300{
 301        if (!value)
 302                return 1;
 303        if (!*value)
 304                return 0;
 305        if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 306                return 1;
 307        if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 308                return 0;
 309        return git_config_int(name, value) != 0;
 310}
 311
 312int git_default_config(const char *var, const char *value)
 313{
 314        /* This needs a better name */
 315        if (!strcmp(var, "core.filemode")) {
 316                trust_executable_bit = git_config_bool(var, value);
 317                return 0;
 318        }
 319
 320        if (!strcmp(var, "core.quotepath")) {
 321                quote_path_fully = git_config_bool(var, value);
 322                return 0;
 323        }
 324
 325        if (!strcmp(var, "core.symlinks")) {
 326                has_symlinks = git_config_bool(var, value);
 327                return 0;
 328        }
 329
 330        if (!strcmp(var, "core.bare")) {
 331                is_bare_repository_cfg = git_config_bool(var, value);
 332                return 0;
 333        }
 334
 335        if (!strcmp(var, "core.ignorestat")) {
 336                assume_unchanged = git_config_bool(var, value);
 337                return 0;
 338        }
 339
 340        if (!strcmp(var, "core.prefersymlinkrefs")) {
 341                prefer_symlink_refs = git_config_bool(var, value);
 342                return 0;
 343        }
 344
 345        if (!strcmp(var, "core.logallrefupdates")) {
 346                log_all_ref_updates = git_config_bool(var, value);
 347                return 0;
 348        }
 349
 350        if (!strcmp(var, "core.warnambiguousrefs")) {
 351                warn_ambiguous_refs = git_config_bool(var, value);
 352                return 0;
 353        }
 354
 355        if (!strcmp(var, "core.loosecompression")) {
 356                int level = git_config_int(var, value);
 357                if (level == -1)
 358                        level = Z_DEFAULT_COMPRESSION;
 359                else if (level < 0 || level > Z_BEST_COMPRESSION)
 360                        die("bad zlib compression level %d", level);
 361                zlib_compression_level = level;
 362                zlib_compression_seen = 1;
 363                return 0;
 364        }
 365
 366        if (!strcmp(var, "core.compression")) {
 367                int level = git_config_int(var, value);
 368                if (level == -1)
 369                        level = Z_DEFAULT_COMPRESSION;
 370                else if (level < 0 || level > Z_BEST_COMPRESSION)
 371                        die("bad zlib compression level %d", level);
 372                core_compression_level = level;
 373                core_compression_seen = 1;
 374                if (!zlib_compression_seen)
 375                        zlib_compression_level = level;
 376                return 0;
 377        }
 378
 379        if (!strcmp(var, "core.packedgitwindowsize")) {
 380                int pgsz_x2 = getpagesize() * 2;
 381                packed_git_window_size = git_config_int(var, value);
 382
 383                /* This value must be multiple of (pagesize * 2) */
 384                packed_git_window_size /= pgsz_x2;
 385                if (packed_git_window_size < 1)
 386                        packed_git_window_size = 1;
 387                packed_git_window_size *= pgsz_x2;
 388                return 0;
 389        }
 390
 391        if (!strcmp(var, "core.packedgitlimit")) {
 392                packed_git_limit = git_config_int(var, value);
 393                return 0;
 394        }
 395
 396        if (!strcmp(var, "core.deltabasecachelimit")) {
 397                delta_base_cache_limit = git_config_int(var, value);
 398                return 0;
 399        }
 400
 401        if (!strcmp(var, "core.autocrlf")) {
 402                if (value && !strcasecmp(value, "input")) {
 403                        auto_crlf = -1;
 404                        return 0;
 405                }
 406                auto_crlf = git_config_bool(var, value);
 407                return 0;
 408        }
 409
 410        if (!strcmp(var, "user.name")) {
 411                strlcpy(git_default_name, value, sizeof(git_default_name));
 412                return 0;
 413        }
 414
 415        if (!strcmp(var, "user.email")) {
 416                strlcpy(git_default_email, value, sizeof(git_default_email));
 417                return 0;
 418        }
 419
 420        if (!strcmp(var, "i18n.commitencoding")) {
 421                git_commit_encoding = xstrdup(value);
 422                return 0;
 423        }
 424
 425        if (!strcmp(var, "i18n.logoutputencoding")) {
 426                git_log_output_encoding = xstrdup(value);
 427                return 0;
 428        }
 429
 430
 431        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 432                pager_use_color = git_config_bool(var,value);
 433                return 0;
 434        }
 435
 436        if (!strcmp(var, "core.pager")) {
 437                pager_program = xstrdup(value);
 438                return 0;
 439        }
 440
 441        if (!strcmp(var, "core.editor")) {
 442                editor_program = xstrdup(value);
 443                return 0;
 444        }
 445
 446        if (!strcmp(var, "core.excludesfile")) {
 447                if (!value)
 448                        die("core.excludesfile without value");
 449                excludes_file = xstrdup(value);
 450                return 0;
 451        }
 452
 453        if (!strcmp(var, "core.whitespace")) {
 454                whitespace_rule_cfg = parse_whitespace_rule(value);
 455                return 0;
 456        }
 457
 458        /* Add other config variables here and to Documentation/config.txt. */
 459        return 0;
 460}
 461
 462int git_config_from_file(config_fn_t fn, const char *filename)
 463{
 464        int ret;
 465        FILE *f = fopen(filename, "r");
 466
 467        ret = -1;
 468        if (f) {
 469                config_file = f;
 470                config_file_name = filename;
 471                config_linenr = 1;
 472                config_file_eof = 0;
 473                ret = git_parse_file(fn);
 474                fclose(f);
 475                config_file_name = NULL;
 476        }
 477        return ret;
 478}
 479
 480const char *git_etc_gitconfig(void)
 481{
 482        static const char *system_wide;
 483        if (!system_wide) {
 484                system_wide = ETC_GITCONFIG;
 485                if (!is_absolute_path(system_wide)) {
 486                        /* interpret path relative to exec-dir */
 487                        const char *exec_path = git_exec_path();
 488                        system_wide = prefix_path(exec_path, strlen(exec_path),
 489                                                system_wide);
 490                }
 491        }
 492        return system_wide;
 493}
 494
 495int git_config(config_fn_t fn)
 496{
 497        int ret = 0;
 498        char *repo_config = NULL;
 499        const char *home = NULL, *filename;
 500
 501        /* $GIT_CONFIG makes git read _only_ the given config file,
 502         * $GIT_CONFIG_LOCAL will make it process it in addition to the
 503         * global config file, the same way it would the per-repository
 504         * config file otherwise. */
 505        filename = getenv(CONFIG_ENVIRONMENT);
 506        if (!filename) {
 507                if (!access(git_etc_gitconfig(), R_OK))
 508                        ret += git_config_from_file(fn, git_etc_gitconfig());
 509                home = getenv("HOME");
 510                filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 511                if (!filename)
 512                        filename = repo_config = xstrdup(git_path("config"));
 513        }
 514
 515        if (home) {
 516                char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 517                if (!access(user_config, R_OK))
 518                        ret = git_config_from_file(fn, user_config);
 519                free(user_config);
 520        }
 521
 522        ret += git_config_from_file(fn, filename);
 523        free(repo_config);
 524        return ret;
 525}
 526
 527/*
 528 * Find all the stuff for git_config_set() below.
 529 */
 530
 531#define MAX_MATCHES 512
 532
 533static struct {
 534        int baselen;
 535        char* key;
 536        int do_not_match;
 537        regex_t* value_regex;
 538        int multi_replace;
 539        size_t offset[MAX_MATCHES];
 540        enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 541        int seen;
 542} store;
 543
 544static int matches(const char* key, const char* value)
 545{
 546        return !strcmp(key, store.key) &&
 547                (store.value_regex == NULL ||
 548                 (store.do_not_match ^
 549                  !regexec(store.value_regex, value, 0, NULL, 0)));
 550}
 551
 552static int store_aux(const char* key, const char* value)
 553{
 554        const char *ep;
 555        size_t section_len;
 556
 557        switch (store.state) {
 558        case KEY_SEEN:
 559                if (matches(key, value)) {
 560                        if (store.seen == 1 && store.multi_replace == 0) {
 561                                fprintf(stderr,
 562                                        "Warning: %s has multiple values\n",
 563                                        key);
 564                        } else if (store.seen >= MAX_MATCHES) {
 565                                fprintf(stderr, "Too many matches\n");
 566                                return 1;
 567                        }
 568
 569                        store.offset[store.seen] = ftell(config_file);
 570                        store.seen++;
 571                }
 572                break;
 573        case SECTION_SEEN:
 574                /*
 575                 * What we are looking for is in store.key (both
 576                 * section and var), and its section part is baselen
 577                 * long.  We found key (again, both section and var).
 578                 * We would want to know if this key is in the same
 579                 * section as what we are looking for.  We already
 580                 * know we are in the same section as what should
 581                 * hold store.key.
 582                 */
 583                ep = strrchr(key, '.');
 584                section_len = ep - key;
 585
 586                if ((section_len != store.baselen) ||
 587                    memcmp(key, store.key, section_len+1)) {
 588                        store.state = SECTION_END_SEEN;
 589                        break;
 590                }
 591
 592                /*
 593                 * Do not increment matches: this is no match, but we
 594                 * just made sure we are in the desired section.
 595                 */
 596                store.offset[store.seen] = ftell(config_file);
 597                /* fallthru */
 598        case SECTION_END_SEEN:
 599        case START:
 600                if (matches(key, value)) {
 601                        store.offset[store.seen] = ftell(config_file);
 602                        store.state = KEY_SEEN;
 603                        store.seen++;
 604                } else {
 605                        if (strrchr(key, '.') - key == store.baselen &&
 606                              !strncmp(key, store.key, store.baselen)) {
 607                                        store.state = SECTION_SEEN;
 608                                        store.offset[store.seen] = ftell(config_file);
 609                        }
 610                }
 611        }
 612        return 0;
 613}
 614
 615static int write_error(void)
 616{
 617        fprintf(stderr, "Failed to write new configuration file\n");
 618
 619        /* Same error code as "failed to rename". */
 620        return 4;
 621}
 622
 623static int store_write_section(int fd, const char* key)
 624{
 625        const char *dot;
 626        int i, success;
 627        struct strbuf sb;
 628
 629        strbuf_init(&sb, 0);
 630        dot = memchr(key, '.', store.baselen);
 631        if (dot) {
 632                strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 633                for (i = dot - key + 1; i < store.baselen; i++) {
 634                        if (key[i] == '"')
 635                                strbuf_addch(&sb, '\\');
 636                        strbuf_addch(&sb, key[i]);
 637                }
 638                strbuf_addstr(&sb, "\"]\n");
 639        } else {
 640                strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 641        }
 642
 643        success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 644        strbuf_release(&sb);
 645
 646        return success;
 647}
 648
 649static int store_write_pair(int fd, const char* key, const char* value)
 650{
 651        int i, success;
 652        int length = strlen(key + store.baselen + 1);
 653        const char *quote = "";
 654        struct strbuf sb;
 655
 656        /*
 657         * Check to see if the value needs to be surrounded with a dq pair.
 658         * Note that problematic characters are always backslash-quoted; this
 659         * check is about not losing leading or trailing SP and strings that
 660         * follow beginning-of-comment characters (i.e. ';' and '#') by the
 661         * configuration parser.
 662         */
 663        if (value[0] == ' ')
 664                quote = "\"";
 665        for (i = 0; value[i]; i++)
 666                if (value[i] == ';' || value[i] == '#')
 667                        quote = "\"";
 668        if (i && value[i - 1] == ' ')
 669                quote = "\"";
 670
 671        strbuf_init(&sb, 0);
 672        strbuf_addf(&sb, "\t%.*s = %s",
 673                    length, key + store.baselen + 1, quote);
 674
 675        for (i = 0; value[i]; i++)
 676                switch (value[i]) {
 677                case '\n':
 678                        strbuf_addstr(&sb, "\\n");
 679                        break;
 680                case '\t':
 681                        strbuf_addstr(&sb, "\\t");
 682                        break;
 683                case '"':
 684                case '\\':
 685                        strbuf_addch(&sb, '\\');
 686                default:
 687                        strbuf_addch(&sb, value[i]);
 688                        break;
 689                }
 690        strbuf_addf(&sb, "%s\n", quote);
 691
 692        success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 693        strbuf_release(&sb);
 694
 695        return success;
 696}
 697
 698static ssize_t find_beginning_of_line(const char* contents, size_t size,
 699        size_t offset_, int* found_bracket)
 700{
 701        size_t equal_offset = size, bracket_offset = size;
 702        ssize_t offset;
 703
 704        for (offset = offset_-2; offset > 0
 705                        && contents[offset] != '\n'; offset--)
 706                switch (contents[offset]) {
 707                        case '=': equal_offset = offset; break;
 708                        case ']': bracket_offset = offset; break;
 709                }
 710        if (bracket_offset < equal_offset) {
 711                *found_bracket = 1;
 712                offset = bracket_offset+1;
 713        } else
 714                offset++;
 715
 716        return offset;
 717}
 718
 719int git_config_set(const char* key, const char* value)
 720{
 721        return git_config_set_multivar(key, value, NULL, 0);
 722}
 723
 724/*
 725 * If value==NULL, unset in (remove from) config,
 726 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 727 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 728 *     else all matching key/values (regardless how many) are removed,
 729 *     before the new pair is written.
 730 *
 731 * Returns 0 on success.
 732 *
 733 * This function does this:
 734 *
 735 * - it locks the config file by creating ".git/config.lock"
 736 *
 737 * - it then parses the config using store_aux() as validator to find
 738 *   the position on the key/value pair to replace. If it is to be unset,
 739 *   it must be found exactly once.
 740 *
 741 * - the config file is mmap()ed and the part before the match (if any) is
 742 *   written to the lock file, then the changed part and the rest.
 743 *
 744 * - the config file is removed and the lock file rename()d to it.
 745 *
 746 */
 747int git_config_set_multivar(const char* key, const char* value,
 748        const char* value_regex, int multi_replace)
 749{
 750        int i, dot;
 751        int fd = -1, in_fd;
 752        int ret;
 753        char* config_filename;
 754        struct lock_file *lock = NULL;
 755        const char* last_dot = strrchr(key, '.');
 756
 757        config_filename = getenv(CONFIG_ENVIRONMENT);
 758        if (!config_filename) {
 759                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 760                if (!config_filename)
 761                        config_filename  = git_path("config");
 762        }
 763        config_filename = xstrdup(config_filename);
 764
 765        /*
 766         * Since "key" actually contains the section name and the real
 767         * key name separated by a dot, we have to know where the dot is.
 768         */
 769
 770        if (last_dot == NULL) {
 771                fprintf(stderr, "key does not contain a section: %s\n", key);
 772                ret = 2;
 773                goto out_free;
 774        }
 775        store.baselen = last_dot - key;
 776
 777        store.multi_replace = multi_replace;
 778
 779        /*
 780         * Validate the key and while at it, lower case it for matching.
 781         */
 782        store.key = xmalloc(strlen(key) + 1);
 783        dot = 0;
 784        for (i = 0; key[i]; i++) {
 785                unsigned char c = key[i];
 786                if (c == '.')
 787                        dot = 1;
 788                /* Leave the extended basename untouched.. */
 789                if (!dot || i > store.baselen) {
 790                        if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 791                                fprintf(stderr, "invalid key: %s\n", key);
 792                                free(store.key);
 793                                ret = 1;
 794                                goto out_free;
 795                        }
 796                        c = tolower(c);
 797                } else if (c == '\n') {
 798                        fprintf(stderr, "invalid key (newline): %s\n", key);
 799                        free(store.key);
 800                        ret = 1;
 801                        goto out_free;
 802                }
 803                store.key[i] = c;
 804        }
 805        store.key[i] = 0;
 806
 807        /*
 808         * The lock serves a purpose in addition to locking: the new
 809         * contents of .git/config will be written into it.
 810         */
 811        lock = xcalloc(sizeof(struct lock_file), 1);
 812        fd = hold_lock_file_for_update(lock, config_filename, 0);
 813        if (fd < 0) {
 814                fprintf(stderr, "could not lock config file\n");
 815                free(store.key);
 816                ret = -1;
 817                goto out_free;
 818        }
 819
 820        /*
 821         * If .git/config does not exist yet, write a minimal version.
 822         */
 823        in_fd = open(config_filename, O_RDONLY);
 824        if ( in_fd < 0 ) {
 825                free(store.key);
 826
 827                if ( ENOENT != errno ) {
 828                        error("opening %s: %s", config_filename,
 829                              strerror(errno));
 830                        ret = 3; /* same as "invalid config file" */
 831                        goto out_free;
 832                }
 833                /* if nothing to unset, error out */
 834                if (value == NULL) {
 835                        ret = 5;
 836                        goto out_free;
 837                }
 838
 839                store.key = (char*)key;
 840                if (!store_write_section(fd, key) ||
 841                    !store_write_pair(fd, key, value))
 842                        goto write_err_out;
 843        } else {
 844                struct stat st;
 845                char* contents;
 846                size_t contents_sz, copy_begin, copy_end;
 847                int i, new_line = 0;
 848
 849                if (value_regex == NULL)
 850                        store.value_regex = NULL;
 851                else {
 852                        if (value_regex[0] == '!') {
 853                                store.do_not_match = 1;
 854                                value_regex++;
 855                        } else
 856                                store.do_not_match = 0;
 857
 858                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 859                        if (regcomp(store.value_regex, value_regex,
 860                                        REG_EXTENDED)) {
 861                                fprintf(stderr, "Invalid pattern: %s\n",
 862                                        value_regex);
 863                                free(store.value_regex);
 864                                ret = 6;
 865                                goto out_free;
 866                        }
 867                }
 868
 869                store.offset[0] = 0;
 870                store.state = START;
 871                store.seen = 0;
 872
 873                /*
 874                 * After this, store.offset will contain the *end* offset
 875                 * of the last match, or remain at 0 if no match was found.
 876                 * As a side effect, we make sure to transform only a valid
 877                 * existing config file.
 878                 */
 879                if (git_config_from_file(store_aux, config_filename)) {
 880                        fprintf(stderr, "invalid config file\n");
 881                        free(store.key);
 882                        if (store.value_regex != NULL) {
 883                                regfree(store.value_regex);
 884                                free(store.value_regex);
 885                        }
 886                        ret = 3;
 887                        goto out_free;
 888                }
 889
 890                free(store.key);
 891                if (store.value_regex != NULL) {
 892                        regfree(store.value_regex);
 893                        free(store.value_regex);
 894                }
 895
 896                /* if nothing to unset, or too many matches, error out */
 897                if ((store.seen == 0 && value == NULL) ||
 898                                (store.seen > 1 && multi_replace == 0)) {
 899                        ret = 5;
 900                        goto out_free;
 901                }
 902
 903                fstat(in_fd, &st);
 904                contents_sz = xsize_t(st.st_size);
 905                contents = xmmap(NULL, contents_sz, PROT_READ,
 906                        MAP_PRIVATE, in_fd, 0);
 907                close(in_fd);
 908
 909                if (store.seen == 0)
 910                        store.seen = 1;
 911
 912                for (i = 0, copy_begin = 0; i < store.seen; i++) {
 913                        if (store.offset[i] == 0) {
 914                                store.offset[i] = copy_end = contents_sz;
 915                        } else if (store.state != KEY_SEEN) {
 916                                copy_end = store.offset[i];
 917                        } else
 918                                copy_end = find_beginning_of_line(
 919                                        contents, contents_sz,
 920                                        store.offset[i]-2, &new_line);
 921
 922                        if (copy_end > 0 && contents[copy_end-1] != '\n')
 923                                new_line = 1;
 924
 925                        /* write the first part of the config */
 926                        if (copy_end > copy_begin) {
 927                                if (write_in_full(fd, contents + copy_begin,
 928                                                  copy_end - copy_begin) <
 929                                    copy_end - copy_begin)
 930                                        goto write_err_out;
 931                                if (new_line &&
 932                                    write_in_full(fd, "\n", 1) != 1)
 933                                        goto write_err_out;
 934                        }
 935                        copy_begin = store.offset[i];
 936                }
 937
 938                /* write the pair (value == NULL means unset) */
 939                if (value != NULL) {
 940                        if (store.state == START) {
 941                                if (!store_write_section(fd, key))
 942                                        goto write_err_out;
 943                        }
 944                        if (!store_write_pair(fd, key, value))
 945                                goto write_err_out;
 946                }
 947
 948                /* write the rest of the config */
 949                if (copy_begin < contents_sz)
 950                        if (write_in_full(fd, contents + copy_begin,
 951                                          contents_sz - copy_begin) <
 952                            contents_sz - copy_begin)
 953                                goto write_err_out;
 954
 955                munmap(contents, contents_sz);
 956        }
 957
 958        if (commit_lock_file(lock) < 0) {
 959                fprintf(stderr, "Cannot commit config file!\n");
 960                ret = 4;
 961                goto out_free;
 962        }
 963
 964        /*
 965         * lock is committed, so don't try to roll it back below.
 966         * NOTE: Since lockfile.c keeps a linked list of all created
 967         * lock_file structures, it isn't safe to free(lock).  It's
 968         * better to just leave it hanging around.
 969         */
 970        lock = NULL;
 971        ret = 0;
 972
 973out_free:
 974        if (lock)
 975                rollback_lock_file(lock);
 976        free(config_filename);
 977        return ret;
 978
 979write_err_out:
 980        ret = write_error();
 981        goto out_free;
 982
 983}
 984
 985static int section_name_match (const char *buf, const char *name)
 986{
 987        int i = 0, j = 0, dot = 0;
 988        for (; buf[i] && buf[i] != ']'; i++) {
 989                if (!dot && isspace(buf[i])) {
 990                        dot = 1;
 991                        if (name[j++] != '.')
 992                                break;
 993                        for (i++; isspace(buf[i]); i++)
 994                                ; /* do nothing */
 995                        if (buf[i] != '"')
 996                                break;
 997                        continue;
 998                }
 999                if (buf[i] == '\\' && dot)
1000                        i++;
1001                else if (buf[i] == '"' && dot) {
1002                        for (i++; isspace(buf[i]); i++)
1003                                ; /* do_nothing */
1004                        break;
1005                }
1006                if (buf[i] != name[j++])
1007                        break;
1008        }
1009        return (buf[i] == ']' && name[j] == 0);
1010}
1011
1012/* if new_name == NULL, the section is removed instead */
1013int git_config_rename_section(const char *old_name, const char *new_name)
1014{
1015        int ret = 0, remove = 0;
1016        char *config_filename;
1017        struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1018        int out_fd;
1019        char buf[1024];
1020
1021        config_filename = getenv(CONFIG_ENVIRONMENT);
1022        if (!config_filename) {
1023                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1024                if (!config_filename)
1025                        config_filename  = git_path("config");
1026        }
1027        config_filename = xstrdup(config_filename);
1028        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1029        if (out_fd < 0) {
1030                ret = error("Could not lock config file!");
1031                goto out;
1032        }
1033
1034        if (!(config_file = fopen(config_filename, "rb"))) {
1035                /* no config file means nothing to rename, no error */
1036                goto unlock_and_out;
1037        }
1038
1039        while (fgets(buf, sizeof(buf), config_file)) {
1040                int i;
1041                int length;
1042                for (i = 0; buf[i] && isspace(buf[i]); i++)
1043                        ; /* do nothing */
1044                if (buf[i] == '[') {
1045                        /* it's a section */
1046                        if (section_name_match (&buf[i+1], old_name)) {
1047                                ret++;
1048                                if (new_name == NULL) {
1049                                        remove = 1;
1050                                        continue;
1051                                }
1052                                store.baselen = strlen(new_name);
1053                                if (!store_write_section(out_fd, new_name)) {
1054                                        ret = write_error();
1055                                        goto out;
1056                                }
1057                                continue;
1058                        }
1059                        remove = 0;
1060                }
1061                if (remove)
1062                        continue;
1063                length = strlen(buf);
1064                if (write_in_full(out_fd, buf, length) != length) {
1065                        ret = write_error();
1066                        goto out;
1067                }
1068        }
1069        fclose(config_file);
1070 unlock_and_out:
1071        if (commit_lock_file(lock) < 0)
1072                        ret = error("Cannot commit config file!");
1073 out:
1074        free(config_filename);
1075        return ret;
1076}