Andrew's git / gitweb.git / config.c
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config.con commit Propagate cache error internal to refresh_cache() via parameter. (ec0cc70)
   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.deltabasecachelimit")) {
 335                delta_base_cache_limit = git_config_int(var, value);
 336                return 0;
 337        }
 338
 339        if (!strcmp(var, "core.autocrlf")) {
 340                if (value && !strcasecmp(value, "input")) {
 341                        auto_crlf = -1;
 342                        return 0;
 343                }
 344                auto_crlf = git_config_bool(var, value);
 345                return 0;
 346        }
 347
 348        if (!strcmp(var, "user.name")) {
 349                strlcpy(git_default_name, value, sizeof(git_default_name));
 350                return 0;
 351        }
 352
 353        if (!strcmp(var, "user.email")) {
 354                strlcpy(git_default_email, value, sizeof(git_default_email));
 355                return 0;
 356        }
 357
 358        if (!strcmp(var, "i18n.commitencoding")) {
 359                git_commit_encoding = xstrdup(value);
 360                return 0;
 361        }
 362
 363        if (!strcmp(var, "i18n.logoutputencoding")) {
 364                git_log_output_encoding = xstrdup(value);
 365                return 0;
 366        }
 367
 368
 369        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 370                pager_use_color = git_config_bool(var,value);
 371                return 0;
 372        }
 373
 374        /* Add other config variables here and to Documentation/config.txt. */
 375        return 0;
 376}
 377
 378int git_config_from_file(config_fn_t fn, const char *filename)
 379{
 380        int ret;
 381        FILE *f = fopen(filename, "r");
 382
 383        ret = -1;
 384        if (f) {
 385                config_file = f;
 386                config_file_name = filename;
 387                config_linenr = 1;
 388                ret = git_parse_file(fn);
 389                fclose(f);
 390                config_file_name = NULL;
 391        }
 392        return ret;
 393}
 394
 395int git_config(config_fn_t fn)
 396{
 397        int ret = 0;
 398        char *repo_config = NULL;
 399        const char *home = NULL, *filename;
 400
 401        /* $GIT_CONFIG makes git read _only_ the given config file,
 402         * $GIT_CONFIG_LOCAL will make it process it in addition to the
 403         * global config file, the same way it would the per-repository
 404         * config file otherwise. */
 405        filename = getenv(CONFIG_ENVIRONMENT);
 406        if (!filename) {
 407                if (!access(ETC_GITCONFIG, R_OK))
 408                        ret += git_config_from_file(fn, ETC_GITCONFIG);
 409                home = getenv("HOME");
 410                filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 411                if (!filename)
 412                        filename = repo_config = xstrdup(git_path("config"));
 413        }
 414
 415        if (home) {
 416                char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 417                if (!access(user_config, R_OK))
 418                        ret = git_config_from_file(fn, user_config);
 419                free(user_config);
 420        }
 421
 422        ret += git_config_from_file(fn, filename);
 423        free(repo_config);
 424        return ret;
 425}
 426
 427/*
 428 * Find all the stuff for git_config_set() below.
 429 */
 430
 431#define MAX_MATCHES 512
 432
 433static struct {
 434        int baselen;
 435        char* key;
 436        int do_not_match;
 437        regex_t* value_regex;
 438        int multi_replace;
 439        size_t offset[MAX_MATCHES];
 440        enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 441        int seen;
 442} store;
 443
 444static int matches(const char* key, const char* value)
 445{
 446        return !strcmp(key, store.key) &&
 447                (store.value_regex == NULL ||
 448                 (store.do_not_match ^
 449                  !regexec(store.value_regex, value, 0, NULL, 0)));
 450}
 451
 452static int store_aux(const char* key, const char* value)
 453{
 454        switch (store.state) {
 455        case KEY_SEEN:
 456                if (matches(key, value)) {
 457                        if (store.seen == 1 && store.multi_replace == 0) {
 458                                fprintf(stderr,
 459                                        "Warning: %s has multiple values\n",
 460                                        key);
 461                        } else if (store.seen >= MAX_MATCHES) {
 462                                fprintf(stderr, "Too many matches\n");
 463                                return 1;
 464                        }
 465
 466                        store.offset[store.seen] = ftell(config_file);
 467                        store.seen++;
 468                }
 469                break;
 470        case SECTION_SEEN:
 471                if (strncmp(key, store.key, store.baselen+1)) {
 472                        store.state = SECTION_END_SEEN;
 473                        break;
 474                } else
 475                        /* do not increment matches: this is no match */
 476                        store.offset[store.seen] = ftell(config_file);
 477                /* fallthru */
 478        case SECTION_END_SEEN:
 479        case START:
 480                if (matches(key, value)) {
 481                        store.offset[store.seen] = ftell(config_file);
 482                        store.state = KEY_SEEN;
 483                        store.seen++;
 484                } else {
 485                        if (strrchr(key, '.') - key == store.baselen &&
 486                              !strncmp(key, store.key, store.baselen)) {
 487                                        store.state = SECTION_SEEN;
 488                                        store.offset[store.seen] = ftell(config_file);
 489                        }
 490                }
 491        }
 492        return 0;
 493}
 494
 495static int write_error()
 496{
 497        fprintf(stderr, "Failed to write new configuration file\n");
 498
 499        /* Same error code as "failed to rename". */
 500        return 4;
 501}
 502
 503static int store_write_section(int fd, const char* key)
 504{
 505        const char *dot = strchr(key, '.');
 506        int len1 = store.baselen, len2 = -1;
 507
 508        dot = strchr(key, '.');
 509        if (dot) {
 510                int dotlen = dot - key;
 511                if (dotlen < len1) {
 512                        len2 = len1 - dotlen - 1;
 513                        len1 = dotlen;
 514                }
 515        }
 516
 517        if (write_in_full(fd, "[", 1) != 1 ||
 518            write_in_full(fd, key, len1) != len1)
 519                return 0;
 520        if (len2 >= 0) {
 521                if (write_in_full(fd, " \"", 2) != 2)
 522                        return 0;
 523                while (--len2 >= 0) {
 524                        unsigned char c = *++dot;
 525                        if (c == '"')
 526                                if (write_in_full(fd, "\\", 1) != 1)
 527                                        return 0;
 528                        if (write_in_full(fd, &c, 1) != 1)
 529                                return 0;
 530                }
 531                if (write_in_full(fd, "\"", 1) != 1)
 532                        return 0;
 533        }
 534        if (write_in_full(fd, "]\n", 2) != 2)
 535                return 0;
 536
 537        return 1;
 538}
 539
 540static int store_write_pair(int fd, const char* key, const char* value)
 541{
 542        int i;
 543        int length = strlen(key+store.baselen+1);
 544        int quote = 0;
 545
 546        /* Check to see if the value needs to be quoted. */
 547        if (value[0] == ' ')
 548                quote = 1;
 549        for (i = 0; value[i]; i++)
 550                if (value[i] == ';' || value[i] == '#')
 551                        quote = 1;
 552        if (value[i-1] == ' ')
 553                quote = 1;
 554
 555        if (write_in_full(fd, "\t", 1) != 1 ||
 556            write_in_full(fd, key+store.baselen+1, length) != length ||
 557            write_in_full(fd, " = ", 3) != 3)
 558                return 0;
 559        if (quote && write_in_full(fd, "\"", 1) != 1)
 560                return 0;
 561        for (i = 0; value[i]; i++)
 562                switch (value[i]) {
 563                case '\n':
 564                        if (write_in_full(fd, "\\n", 2) != 2)
 565                                return 0;
 566                        break;
 567                case '\t':
 568                        if (write_in_full(fd, "\\t", 2) != 2)
 569                                return 0;
 570                        break;
 571                case '"':
 572                case '\\':
 573                        if (write_in_full(fd, "\\", 1) != 1)
 574                                return 0;
 575                default:
 576                        if (write_in_full(fd, value+i, 1) != 1)
 577                                return 0;
 578                        break;
 579                }
 580        if (quote && write_in_full(fd, "\"", 1) != 1)
 581                return 0;
 582        if (write_in_full(fd, "\n", 1) != 1)
 583                return 0;
 584        return 1;
 585}
 586
 587static ssize_t find_beginning_of_line(const char* contents, size_t size,
 588        size_t offset_, int* found_bracket)
 589{
 590        size_t equal_offset = size, bracket_offset = size;
 591        ssize_t offset;
 592
 593        for (offset = offset_-2; offset > 0 
 594                        && contents[offset] != '\n'; offset--)
 595                switch (contents[offset]) {
 596                        case '=': equal_offset = offset; break;
 597                        case ']': bracket_offset = offset; break;
 598                }
 599        if (bracket_offset < equal_offset) {
 600                *found_bracket = 1;
 601                offset = bracket_offset+1;
 602        } else
 603                offset++;
 604
 605        return offset;
 606}
 607
 608int git_config_set(const char* key, const char* value)
 609{
 610        return git_config_set_multivar(key, value, NULL, 0);
 611}
 612
 613/*
 614 * If value==NULL, unset in (remove from) config,
 615 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 616 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 617 *     else all matching key/values (regardless how many) are removed,
 618 *     before the new pair is written.
 619 *
 620 * Returns 0 on success.
 621 *
 622 * This function does this:
 623 *
 624 * - it locks the config file by creating ".git/config.lock"
 625 *
 626 * - it then parses the config using store_aux() as validator to find
 627 *   the position on the key/value pair to replace. If it is to be unset,
 628 *   it must be found exactly once.
 629 *
 630 * - the config file is mmap()ed and the part before the match (if any) is
 631 *   written to the lock file, then the changed part and the rest.
 632 *
 633 * - the config file is removed and the lock file rename()d to it.
 634 *
 635 */
 636int git_config_set_multivar(const char* key, const char* value,
 637        const char* value_regex, int multi_replace)
 638{
 639        int i, dot;
 640        int fd = -1, in_fd;
 641        int ret;
 642        char* config_filename;
 643        char* lock_file;
 644        const char* last_dot = strrchr(key, '.');
 645
 646        config_filename = getenv(CONFIG_ENVIRONMENT);
 647        if (!config_filename) {
 648                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 649                if (!config_filename)
 650                        config_filename  = git_path("config");
 651        }
 652        config_filename = xstrdup(config_filename);
 653        lock_file = xstrdup(mkpath("%s.lock", config_filename));
 654
 655        /*
 656         * Since "key" actually contains the section name and the real
 657         * key name separated by a dot, we have to know where the dot is.
 658         */
 659
 660        if (last_dot == NULL) {
 661                fprintf(stderr, "key does not contain a section: %s\n", key);
 662                ret = 2;
 663                goto out_free;
 664        }
 665        store.baselen = last_dot - key;
 666
 667        store.multi_replace = multi_replace;
 668
 669        /*
 670         * Validate the key and while at it, lower case it for matching.
 671         */
 672        store.key = xmalloc(strlen(key) + 1);
 673        dot = 0;
 674        for (i = 0; key[i]; i++) {
 675                unsigned char c = key[i];
 676                if (c == '.')
 677                        dot = 1;
 678                /* Leave the extended basename untouched.. */
 679                if (!dot || i > store.baselen) {
 680                        if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 681                                fprintf(stderr, "invalid key: %s\n", key);
 682                                free(store.key);
 683                                ret = 1;
 684                                goto out_free;
 685                        }
 686                        c = tolower(c);
 687                } else if (c == '\n') {
 688                        fprintf(stderr, "invalid key (newline): %s\n", key);
 689                        free(store.key);
 690                        ret = 1;
 691                        goto out_free;
 692                }
 693                store.key[i] = c;
 694        }
 695        store.key[i] = 0;
 696
 697        /*
 698         * The lock_file serves a purpose in addition to locking: the new
 699         * contents of .git/config will be written into it.
 700         */
 701        fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 702        if (fd < 0 || adjust_shared_perm(lock_file)) {
 703                fprintf(stderr, "could not lock config file\n");
 704                free(store.key);
 705                ret = -1;
 706                goto out_free;
 707        }
 708
 709        /*
 710         * If .git/config does not exist yet, write a minimal version.
 711         */
 712        in_fd = open(config_filename, O_RDONLY);
 713        if ( in_fd < 0 ) {
 714                free(store.key);
 715
 716                if ( ENOENT != errno ) {
 717                        error("opening %s: %s", config_filename,
 718                              strerror(errno));
 719                        ret = 3; /* same as "invalid config file" */
 720                        goto out_free;
 721                }
 722                /* if nothing to unset, error out */
 723                if (value == NULL) {
 724                        ret = 5;
 725                        goto out_free;
 726                }
 727
 728                store.key = (char*)key;
 729                if (!store_write_section(fd, key) ||
 730                    !store_write_pair(fd, key, value))
 731                        goto write_err_out;
 732        } else {
 733                struct stat st;
 734                char* contents;
 735                size_t contents_sz, copy_begin, copy_end;
 736                int i, new_line = 0;
 737
 738                if (value_regex == NULL)
 739                        store.value_regex = NULL;
 740                else {
 741                        if (value_regex[0] == '!') {
 742                                store.do_not_match = 1;
 743                                value_regex++;
 744                        } else
 745                                store.do_not_match = 0;
 746
 747                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 748                        if (regcomp(store.value_regex, value_regex,
 749                                        REG_EXTENDED)) {
 750                                fprintf(stderr, "Invalid pattern: %s\n",
 751                                        value_regex);
 752                                free(store.value_regex);
 753                                ret = 6;
 754                                goto out_free;
 755                        }
 756                }
 757
 758                store.offset[0] = 0;
 759                store.state = START;
 760                store.seen = 0;
 761
 762                /*
 763                 * After this, store.offset will contain the *end* offset
 764                 * of the last match, or remain at 0 if no match was found.
 765                 * As a side effect, we make sure to transform only a valid
 766                 * existing config file.
 767                 */
 768                if (git_config_from_file(store_aux, config_filename)) {
 769                        fprintf(stderr, "invalid config file\n");
 770                        free(store.key);
 771                        if (store.value_regex != NULL) {
 772                                regfree(store.value_regex);
 773                                free(store.value_regex);
 774                        }
 775                        ret = 3;
 776                        goto out_free;
 777                }
 778
 779                free(store.key);
 780                if (store.value_regex != NULL) {
 781                        regfree(store.value_regex);
 782                        free(store.value_regex);
 783                }
 784
 785                /* if nothing to unset, or too many matches, error out */
 786                if ((store.seen == 0 && value == NULL) ||
 787                                (store.seen > 1 && multi_replace == 0)) {
 788                        ret = 5;
 789                        goto out_free;
 790                }
 791
 792                fstat(in_fd, &st);
 793                contents_sz = xsize_t(st.st_size);
 794                contents = xmmap(NULL, contents_sz, PROT_READ,
 795                        MAP_PRIVATE, in_fd, 0);
 796                close(in_fd);
 797
 798                if (store.seen == 0)
 799                        store.seen = 1;
 800
 801                for (i = 0, copy_begin = 0; i < store.seen; i++) {
 802                        if (store.offset[i] == 0) {
 803                                store.offset[i] = copy_end = contents_sz;
 804                        } else if (store.state != KEY_SEEN) {
 805                                copy_end = store.offset[i];
 806                        } else
 807                                copy_end = find_beginning_of_line(
 808                                        contents, contents_sz,
 809                                        store.offset[i]-2, &new_line);
 810
 811                        /* write the first part of the config */
 812                        if (copy_end > copy_begin) {
 813                                if (write_in_full(fd, contents + copy_begin,
 814                                                  copy_end - copy_begin) <
 815                                    copy_end - copy_begin)
 816                                        goto write_err_out;
 817                                if (new_line &&
 818                                    write_in_full(fd, "\n", 1) != 1)
 819                                        goto write_err_out;
 820                        }
 821                        copy_begin = store.offset[i];
 822                }
 823
 824                /* write the pair (value == NULL means unset) */
 825                if (value != NULL) {
 826                        if (store.state == START) {
 827                                if (!store_write_section(fd, key))
 828                                        goto write_err_out;
 829                        }
 830                        if (!store_write_pair(fd, key, value))
 831                                goto write_err_out;
 832                }
 833
 834                /* write the rest of the config */
 835                if (copy_begin < contents_sz)
 836                        if (write_in_full(fd, contents + copy_begin,
 837                                          contents_sz - copy_begin) <
 838                            contents_sz - copy_begin)
 839                                goto write_err_out;
 840
 841                munmap(contents, contents_sz);
 842                unlink(config_filename);
 843        }
 844
 845        if (rename(lock_file, config_filename) < 0) {
 846                fprintf(stderr, "Could not rename the lock file?\n");
 847                ret = 4;
 848                goto out_free;
 849        }
 850
 851        ret = 0;
 852
 853out_free:
 854        if (0 <= fd)
 855                close(fd);
 856        free(config_filename);
 857        if (lock_file) {
 858                unlink(lock_file);
 859                free(lock_file);
 860        }
 861        return ret;
 862
 863write_err_out:
 864        ret = write_error();
 865        goto out_free;
 866
 867}
 868
 869static int section_name_match (const char *buf, const char *name)
 870{
 871        int i = 0, j = 0, dot = 0;
 872        for (; buf[i] && buf[i] != ']'; i++) {
 873                if (!dot && isspace(buf[i])) {
 874                        dot = 1;
 875                        if (name[j++] != '.')
 876                                break;
 877                        for (i++; isspace(buf[i]); i++)
 878                                ; /* do nothing */
 879                        if (buf[i] != '"')
 880                                break;
 881                        continue;
 882                }
 883                if (buf[i] == '\\' && dot)
 884                        i++;
 885                else if (buf[i] == '"' && dot) {
 886                        for (i++; isspace(buf[i]); i++)
 887                                ; /* do_nothing */
 888                        break;
 889                }
 890                if (buf[i] != name[j++])
 891                        break;
 892        }
 893        return (buf[i] == ']' && name[j] == 0);
 894}
 895
 896/* if new_name == NULL, the section is removed instead */
 897int git_config_rename_section(const char *old_name, const char *new_name)
 898{
 899        int ret = 0, remove = 0;
 900        char *config_filename;
 901        struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
 902        int out_fd;
 903        char buf[1024];
 904
 905        config_filename = getenv(CONFIG_ENVIRONMENT);
 906        if (!config_filename) {
 907                config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 908                if (!config_filename)
 909                        config_filename  = git_path("config");
 910        }
 911        config_filename = xstrdup(config_filename);
 912        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 913        if (out_fd < 0) {
 914                ret = error("Could not lock config file!");
 915                goto out;
 916        }
 917
 918        if (!(config_file = fopen(config_filename, "rb"))) {
 919                ret = error("Could not open config file!");
 920                goto out;
 921        }
 922
 923        while (fgets(buf, sizeof(buf), config_file)) {
 924                int i;
 925                int length;
 926                for (i = 0; buf[i] && isspace(buf[i]); i++)
 927                        ; /* do nothing */
 928                if (buf[i] == '[') {
 929                        /* it's a section */
 930                        if (section_name_match (&buf[i+1], old_name)) {
 931                                ret++;
 932                                if (new_name == NULL) {
 933                                        remove = 1;
 934                                        continue;
 935                                }
 936                                store.baselen = strlen(new_name);
 937                                if (!store_write_section(out_fd, new_name)) {
 938                                        ret = write_error();
 939                                        goto out;
 940                                }
 941                                continue;
 942                        }
 943                        remove = 0;
 944                }
 945                if (remove)
 946                        continue;
 947                length = strlen(buf);
 948                if (write_in_full(out_fd, buf, length) != length) {
 949                        ret = write_error();
 950                        goto out;
 951                }
 952        }
 953        fclose(config_file);
 954        if (close(out_fd) || commit_lock_file(lock) < 0)
 955                        ret = error("Cannot commit config file!");
 956 out:
 957        free(config_filename);
 958        return ret;
 959}
 960